ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (2,802)
  • Springer  (2,802)
  • American Chemical Society
  • 1995-1999  (2,802)
  • 1996  (2,802)
  • Computer Science  (2,802)
Collection
  • Articles  (2,802)
Source
Keywords
Publisher
Years
  • 1995-1999  (2,802)
Year
Journal
Topic
  • 1
    Electronic Resource
    Electronic Resource
    The fractional greedy algorithm for data compression (1996)
    Springer
    Computing 56 (1996), S. 29-46 
    Details
    ISSN: 1436-5057
    Keywords: 94A15 ; Optimal and heuristic encoding ; shortest paths ; textual substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es werden Text-Komprimierungsprobleme behandelt, bei denen Teilworte durch Codeworte ersetzt werden, sodaß der ursprüngliche Text durch eine kürzere Codesequenz repräsentiert wird. Das geschieht mit Hilfe eines statischen Wörterbuchs. Wir führen eine neue effiziente on-line Heuristik ein, welche die lokale Komprimierungsrate maximiert. Von diesem fractional greedy Verfahren wird das Verhalten im schlechtesten Fall für verschiedene Typen von Wörterbüchern untersucht.
    Notes: Abstract Text-compression problems are considered where substrings are substitued by code-words according to a static dictionary such that the original text is encoded by a shorter code sequence. We introduce a new efficient on-line heuristic which locally maximizes the compaction ratio. The worst-case behaviour of this fractional greedy heuristic is investigated for several types of dictionaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238290
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A note on stability investigations for Rosenbrock-type methods for quasilinear-implicit differential equations (1996)
    Springer
    Computing 56 (1996), S. 47-59 
    Details
    ISSN: 1436-5057
    Keywords: 65 L 05 ; Rosenbrock-type methods ; quasilinear-implicit differential equations ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Bei der Lösung quasilinear-impliziter ODEs mittels Rosenbrock-Typ-Methoden können trotz guter Stabilitätseigenschaften (A- bzw. L-Stabilität) des Grundverfahrens Stabilitätsprobleme auftreten. Diese Schwierigkeiten sind auf Ungenauigkeiten bei der Berechnung künstlich eingeführter Komponenten (Überführung in DAEs) zurückzuführen. Die Arbeit untersucht die Ursachen für diese Effekte und zeigt Möglichkeiten, diese zu überwinden.
    Notes: Abstract The solution of quasilinear-implicit ODEs using Rosenbrock type methods may suffer from stability problems despite stability properties such as A-stability or L-stability, respectively. These problems are caused by inexact computation of artificial introduced components (transformation to DAE system). The paper investigates the source of the numerical difficulties and shows modifications to overcome them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238291
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Schwarz iterations for the efficient solution of screen problems with boundary elements (1996)
    Springer
    Computing 56 (1996), S. 61-85 
    Details
    ISSN: 1436-5057
    Keywords: 65N55 ; 65N38 ; Boundary integral equations ; domain decomposition ; Schwarz methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Es werden zwei Gebietszerlegungsalgorithmen für die numerische Behandlung von Randintegralgleichungen der ersten Art untersucht. Die Verfahren beruhen auf derh-Version der Galerkinmethode für Randelemente, auf die die multiplikative und die additive Schwarz-Methode angewandt werden. Für zweidimensionale Probleme wird gezeigt, daß die Konvergenzraten beider Methoden unabhängig von der Anzahl der Unbekannten sind. Numerische Resultate für einfache zweidimensionale und dreidimensionale Modellprobleme, die von der Laplace-Gleichung mit Dirichlet oder Neumann-Randbedingungen stammen, werden diskutiert. Eine Gebietszerlegungsstrategie für den Fall vieler Teilgebiete wird anhand eines dreidimensionalen Schirmproblems demonstriert.
    Notes: Abstract This paper investigates two domain decomposition algorithms for the numerical solution of boundary integral equations of the first kind. The schemes are based on theh-type boundary element Galerkin method to which the multiplicative and the additive Schwarz methods are applied. As for twodimensional problems, the rates of convergence of both methods are shown to be independent of the number of unknowns. Numerical results for standard model problems arising from Laplaces' equation with Dirichlet or Neumann boundary conditions in both two and three dimensions are discussed. A multidomain decomposition strategy is indicated by means of a screen problem in three dimensions, so as to obtain satisfactory experimental convergence rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238292
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Massively parallel methods for semiconductor device modelling (1996)
    Springer
    Computing 56 (1996), S. 1-27 
    Details
    ISSN: 1436-5057
    Keywords: 65F10 ; 65H10 ; 65N22 ; 65N30 ; 65N55 ; Semiconductor device ; drift-diffusion equations ; finite element methods ; Gummel's method ; preconditioned conjugate gradient methods ; Schur complement ; domain decomposition massively parallel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Diese Arbeit enthält die Beschreibung, Analyse und Implementierung eines parallelen iterativen Verfahrens zur Lösung der stationären Drift-Diffusions-Gleichung für ein zweidimensionales Halbleitermodell. Die Unbekannten unseres Modells sind das elektrostatische Potential und die Quasi-Fermi-Potentiale der Elektronen und Löcher. Unsere Diskretisierung verwendet die Finite-Element-Methode mit ‘mass limping’ für das elektrostatische Potential und hybride Elemente mit lokaler Stromerhaltung für die Kontinuitätsgleichung. Zur Lösung der entsprechenden nichtlinearen Gleichungen wird eine Version des Gummel-Algorithmus verwendet, der lediglich die Lösung positiv definiter, symmetrischer linearer Gleichungssysteme erfordert. Wir zeigen, daß diese Methode eine Konvergenzrate besitzt, die nur logarithmisch von der Schrittweite abhängt. Die (inneren) nichtlinearen Löser der elektrostatischen Potentialgleichung konvergieren gitterunabhängig quadratisch. Wir beschreiben auch eine Implementierung auf einem MasPar MP-1-Parallelrechner, wobei die auftretenden linearen Systeme mit einem vorkonditionierten cg-Verfahren approximiert werden. Gebietszerlegungsmethoden werden eingesetzt, um die notwendige Matrix-Vektor-Multiplikation zu parallelisieren und Vorkonditionierer dieser schlechtkonditionierten Systeme zu erstellen. Die vorkonditionierten linearen Löser haben ebenfalls eine Konvergenzrate, die logarithmisch vom Verhältnis Teilgebietsgröße zu Schrittweite abhängt und welche robust ist bezüglich stark variierenden Koeffizientenfunktionen des zugrundeliegenden elliptischen Operators. Experimente auf einem Parallelrechner werden diskutiert.
    Notes: Abstract In this paper we describe, analyse and implement a parallel iterative method for the solution of the steady-state drift diffusion equations governing the behaviour of a semiconductor device in two space dimensions. The unknowns in our model are the electrostatic potential and the electron and hole quasi-Fermi potentials. Our discretisation consists of a finite element method with mass lumping for the electrostatic potential equation and a hybrid finite element with local current conservation properties for the continuity equations. A version of Gummel's decoupling algorithm which only requires the solution of positive definite symmetric linear systems is used to solve the resulting nonlinear equations. We show that this method has an overall rate of convergence which only degrades logarithmically as the mesh is refined. Indeed the (inner) nonlinear solves of the electrostatic potential equation converge quadratically, with a mesh independent asymptotic constant. We also describe an implementation on a MasPar MP-1 data parallel machine, where the required linear systems are solved by the preconditioned conjugate gradient method. Domain decomposition methods are used to parallelise the required matrix-vector multiplications and to build preconditioners for these very poorly-conditioned systems. Our preconditioned linear solves also have a rate of convergence which degrades logarithmically as the grid is refined relative to subdomain size, and their performance is resilient to the severe layers which arise in the coefficients of the underlying elliptic operators. Parallel experiments are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238289
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Numerical integration formulas based on iterated cubic splines II (1996)
    Springer
    Computing 56 (1996), S. 87-93 
    Details
    ISSN: 1436-5057
    Keywords: 41A15 ; 65D30 ; Integration formulas ; iterated cubic splines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir erarbeiten eine Anwendung iterativer kubischer Splines auf die numerische Integrationsformeln. Wir geben einige numerische Beispiele, um den Nutzen unserer Methoden zu illustrieren.
    Notes: Abstract We consider an application of iterated cubic splines to numerical integration formulas. Some numerical examples are given to illustrate usefulness of our methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238293
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Randomized online algorithms for maximizing busy time interval scheduling (1996)
    Springer
    Computing 56 (1996), S. 95-104 
    Details
    ISSN: 1436-5057
    Keywords: 68M20 ; Probabilistic algorithm ; online scheduling ; interval ; busy time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir betrachten das Problem der Zuteilung von Aufgaben bestimmter Rechenzeit auf einem Rechner, um so seine Auslastung zu maximieren. Die Aufgabe besteht darin, einen probabilistischen Online-Algorithmus mit vernünftigem worst-case Performance-Verhältnis zu finden. Wir geben die Antwort auf ein offenes Problem von Lipton und Tompkins, das das bestmögliche Verhältnis betrifft. Weiter verallgemeinern wir ihre Ergebnisse auf einm-Maschinen-Analogon. Schließlich wird eine Variante des Problems analysiert, in dem der Rechner mit einem Zwischenspeicher für einen Job versehen ist.
    Notes: Abstract We consider the problem of scheduling tasks requiring certain processing times on one machine so that the busy time of the machine is maximized. The problem is to find a probabilistic online algorithm with reasonable worst case performance ratio. We answer an open problem of Lipton and Tompkins concerning the best possible ratio that can be achieved. Furthermore, we extend their results to anm-machine analogue. Finally, a variant of the problem is analyzed, in which the machine is provided with a buffer to store one job.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02309339
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    On a possible error of type II in statistical evaluation of pseudo-random number generators (1996)
    Springer
    Computing 56 (1996), S. 105-116 
    Details
    ISSN: 1436-5057
    Keywords: 65C10 ; 62M99 ; 62F03 ; Pseudo-random number generators ; statistical evaluation ; tests ; error of type II ; renewal process
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In einem früheren Artikel, vgl. [7], hat die erste Autorin Bewertungsmethoden von Pseudozufallsgeneratoren entwickelt, die auf Ideen der Computer-Simulation basieren. Dabei werden die Pseudozufallszahlen des getesteten Generators zur Modellierung gewisser Verteilungen herangezogen. Diese kann man mit theoretischen Verteilungen oder mit Verteilungen, die mittels wohlbekannter kanonischer Generatoren modelliert werden, vergleichen. Obige Methode kann aber versagen, falls wesentlich verschiedene Generatoren die Simulationen ausführen, welche mit Hilfe unserer einfachen Tests nicht auseinandergehalten werden können. In diesem Artikel werden Typen von kritischen Verteilungen konstruiert, die geometrisch bzw. arithmetisch gennant werden und durch bestimmte Bedingungen dargestellt werden. Es wird darauf hingewiesen, wie die Teilintervall-Methode, welche von den in [7] eingeführten Tests hergeleitet wird, zur Aufdeckung der kritischen Verteilungstype angewendet werden kann. In zusätczlichen Bemerkungen werden noch weitere Anwendungsaspekte unserer Bewertungsmethode betrachtet.
    Notes: Abstract In an earlier paper, cf. [7], the first author developed methods for evaluation of pseudo-random number generators based on ideas of computer simulation. More precisely, pseudo-random numbers of the tested generator are used to model certain distributions which can be compared with theoretical ones or with distributions modeled by means of well-known canonical generators. But this method can fail if essentially different generators produce simulations that cannot be distinguished by means of simple statistical tests developed in [7]. In the present paper two critical types of distributions, named geometric and arthmetic, are constructed that illustrate the circumstances above. Also it is shown how the subinterval method derived from the tests in [7] can serve to detect the described critical types of distributions. Additional aspects of old and new methods are shortly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02309340
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Further analysis of the local defect correction method (1996)
    Springer
    Computing 56 (1996), S. 117-139 
    Details
    ISSN: 1436-5057
    Keywords: 65N22 ; 65N50 ; Local defect correction ; fast adaptive composite grid method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir analysieren einen Spezialfall der lokalen Defektkorrektur-Methode (LDC) die in [4] eingeführt wurde. Wir beschränken uns auf Finite-Differenzen-Diskretisierungen elliptischer Randwertprobleme. Die lokale Defektkorrektur-Methode verwendet Diskretisierungen auf einem globalen uniformen groben Gitter und einem oder mehreren lokalen uniformen feinen Gittern zur Approximation der stetigen Lösung. Wir beweisen, daß diese LDC-Methode als iterative Methode zur Lösung einer zugehörigen Diskretisierung auf dem zusammengesetzten Gitter betrachtet werden kann. Dieses Resultat ermöglicht es, wichtige Eigenschaften der LDC-Methode zu erklären, z.B. in Bezug auf die Größenordnung des Diskretisierungsfehlers. Außerdem ermöglicht die Formulierung der LDC-Methode als iterativer Solver für ein gegebenes Problem auf dem zusammengesetzten Gitter den Beweis eines engen Zusammenhangs zwischen LDC und der “Fast adaptive grid (FAC)”-Methode aus [8–10].
    Notes: Abstract We analyze a special case of the Local Defect Correction (LDC) method introduced in [4]. We restrict ourselves to finite difference discretizations of elliptic boundary value problems. The LDC method uses the discretization on a uniform global coarse grid and on one or more uniform local fine grids for approximating the continuous solution. We prove that this LDC method can be seen as an iterative method for solving an underlying composite grid discretization. This result makes it possible to explain important properties of the LDC method, e.g. concerning the size of the discretization error. Furthermore, the formulation of LDC as an iterative solver for a given composite grid problem makes it possible to prove a close correspondence between LDC and the Fast Adaptive Composite grid (FAC) method from [8–10].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02309341
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Worst-Case analysis of the FFH algorithm for online variable-sized bin packing (1996)
    Springer
    Computing 56 (1996), S. 165-172 
    Details
    ISSN: 1436-5057
    Keywords: 90B35 ; 90C27 ; Combinatorial problems ; bin packing ; online algorithm ; worst-case analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir analysieren den von Kinnersley und Langston [5] vorgeschlagenen FFH-Algorithmus. Wir zeigen, daß der FFH Algorithmus eine scharfe Worst-Case Schranke von 1.7 hat und beantworten damit eine Frage in [5]. Variable Bingrößen werden ebenfalls betrachtet.
    Notes: Abstract We investigate and analyze the FFH algorithm proposed by Kinnersley and Langston [5]. We prove that the tight worst-case performance bound of FFH algorithm is 1.7, thereby answering a question in [5]. The case that bin sizes can be chosen is also considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02309343
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Parallel solvers for linear and nonlinear exterior magnetic field problems based upon coupled FE/BE Formulations (1996)
    Springer
    Computing 56 (1996), S. 237-258 
    Details
    ISSN: 1436-5057
    Keywords: 65N55 ; 65N30 ; 65N22 ; 65N38 ; 78A30 ; Nonlinear partial differential equations ; domain decomposition ; boundary element methods ; finite element methods ; coupling ; magnetic field calculations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In der vorliegenden Arbeit wird ein effizienter paralleler Algorithmus zur Lösung linearer und nichtlinearer Außenraumprobleme, wie sie z.B. in der Magnetostatik auftreten, beschrieben. Er basiert auf der Kopplung der Finite Elemente Methode mit der Galerkin-Randelementmethode mit Hilfe von Gebietszerlegungstechniken über eine einheitliche Variationsformulierung. Auf diese Weise können z.B. Magnetfeldprobleme mit der Sommerfeldschen Abstrahlbedingung vollständig modelliert werden. Die durch die Galerkin-Randelementmethode entstehende nichtsymmetrische Matrix wird in eine symmetrische indefinite Matrix transformiert, um Bramble/Pasciak's CG-Verfahren für indefinite Systeme anzuwenden. Zur Vorkonditionierung werden die neuesten Resultate auf dem Gebiet der Gebietszerlegungsmethoden genutzt. Numerische Resultate, die für zwei praktisch interessante Probleme, darunter ein nichtlineares, auf einem Mehrprozessorsystem erhalten wurden, werden diskutiert.
    Notes: Abstract An efficient parallel algorithm for solving linear and nonlinear exterior boundary value problems arising, e.g., in magnetostatics is presented. It is based upon the domaindecomposition-(DD)-coupling of Finite Element and Galerkin Boundary Element Methods which results in a unified variational formulation. In this way, e.g., magnetic field problems in an unbounded domain with Sommerfeld's radiation condition can be modelled correctly. The problem of a nonsymmetric system matrix due to Galerkin-BEM is overcome by transforming it into a symmetric but indefinite matrix and applying Bramble/Pasciak's CG for indefinite systems. For preconditioning, the main ideas of recent DD research are being applied. Test computations on a multiprocessor system were performed for two problems of practical interest including a nonlinear example.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238514
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    On a robust multigrid solver (1996)
    Springer
    Computing 56 (1996), S. 303-322 
    Details
    ISSN: 1436-5057
    Keywords: 65N20 ; 65N30 ; 65N55 ; Multigrid ; elliptic problems ; anisotropy ; convection-dominated
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir betrachten eine Zweigittermethode, die auf der Approximation des Schurkomplements basiert. Wir untersuchen die Abhängigkeit der Zweigitter-Konvergenzrate von bestimmten Parametern des Problems. Als Testprobleme wählen wir die rotierte anisotrope Diffusionsgleichung und die Konvektions-Diffusions-Gleichung. Mittels Fourieranalyse zeigen wir, daß die Zweigittermethode robust bezüglich Variationen in den relevanten Parametern des Problems ist. Als Mehrgittermethode verwenden wir einen üblichenW-Zyklus auf groben Gittern. Diese Mehrgittermethode hat dann dieselbe algorithmische Struktur wie eine Standard-Mehrgittermethode und ist effizient. Weiters erhalten wir bei Anwendung auf die zwei Testprobleme ebenso wie für die Zweigittermethode starke Robustheit bezüglich Variation der Problemparameter.
    Notes: Abstract We consider a two-grid method based on approximation of the Schur complement. We study the dependence of the two-grid convergence rate on certain problem parameters. As test problems we take the rotated anisotropic diffusion equation and the convection-diffusion equation. Using Fourier analysis we show that for both test problems the two-grid method is robust w.r.t. variation in the relevant problem parameters. For the multigrid method we use a standardW-cycle on coarse grids. This multigrid method then has the same algorithmic structure as a standard multigrid method and is fairly efficient. Moreover, when applied to the two test problems then, as in the two-grid method, we have a strong robustness w.r.t. variation of the problem parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238516
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    A wavelet Galerkin method for the stokes equations (1996)
    Springer
    Computing 56 (1996), S. 259-301 
    Details
    ISSN: 1436-5057
    Keywords: 15A12 ; 35Q30 ; 65N30 ; 41A17 ; 41A63 ; Saddle point problems ; LBB condition ; multiresolution analysis ; wavelets ; time dependent problems ; Schur complements ; preconditioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In dieser Arbeit werden Galerkin-Verfahren für das Stokes-Problem untersucht, die auf speziell angepaßten Multiresolution-Ansätzen beruhen. Insbesondere wird gezeigt, daß gewisse Konstruktionsprinzipien für Wavelets auf gleichförmigen Gittern für jede Raumdimension und beliebige gewünschte Exaktheitsordnung auf Parre von Ansatzräumen führen, die die Ladyšenskaja-Babuška-Brezzi-Bedingung erfüllen. Darüber hinaus ergeben sich auch im instationären Fall aus den entsprechenden stabilen Multiskalenzerlegungen effiziente Vorkonditionierer für die Schurkomplemente entsprechenden systemmatrizen. Die Ergebnisse werden anhand einiger konkreter Realisierungen und numerischer Tests illustriert.
    Notes: Abstract The purpose of this paper is to investigate Galerkin schemes for the Stokes equations based on a suitably adapted multiresolution analysis. In particular, it will be shown that techniques developed in connection with shift-invariant refinable spaces give rise to trial spaces of any desired degree of accuracy satisfying the Ladyšenskaja-Babuška-Brezzi condition for any spatial dimension. Moreover, in the time dependent case efficient preconditioners for the Schur complements of the discrete systems of equations can be based on corresponding stable multiscale decompositions. The results are illustrated by some concrete examples of adapted wavelets and corresponding numerical experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238515
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    PiecewiseC 1-shape-preserving Hermite interpolation (1996)
    Springer
    Computing 56 (1996), S. 323-341 
    Details
    ISSN: 1436-5057
    Keywords: 65D05 ; 65D07 ; 65D10 ; Piece wise Hermite interpolation ; shape preserving
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Ein lokaler Ansatz zur stückweisenC 1-Hermite-Interpolation wird vorgestellt. Die Interpolierende besteht aus zusammengesetzten kubischen und quadratischen Segmenten; sie erhält die Monotonie und/oder die Konvexität der Daten. Unter geeigneten Voraussetzungen approximier sie von vierter Ordnung.
    Notes: Abstract A local scheme for piecewiseC 1-Hermite interpolation is presented. The interpolant is obtained patching together cubic with quadratic polynomial segments; it is co-monotone and/or co-convex with the data. Under appropriate assumptions the method is fourth-order accurate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02253459
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    The exact region of stability for MacCormack scheme (1996)
    Springer
    Computing 56 (1996), S. 371-383 
    Details
    ISSN: 1436-5057
    Keywords: 65M10 ; Stability ; MacCormack scheme ; advection equation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir betrachten die zweidimensionale skalare Advektionsgleichung $$\frac{{\partial u}}{{\partial t}} = \hat a\frac{{\partial u}}{{\partial x}} + \hat b\frac{{\partial u}}{{\partial y}}$$ und zeigen, daß der Stabilitätsbereich des MacCormack-Schemasgenau durch $$\left( {\hat a\frac{{\Delta _t }}{{\Delta _x }}} \right)^{2/3} + \left( {\hat b\frac{{\Delta _t }}{{\Delta _x }}} \right)^{2/3} \leqslant 1$$ gegeben ist, wo Δ t , Δ x and δ y die Gitterabstände sind. Interessanterweise ist dieser Stabilitätsbereich identisch mit dem von Turkel für das Lax-Wendroff-Schema bestimmten Stabilitätsbereich.
    Notes: Abstract Let the two dimensional scalar advection equation be given by $$\frac{{\partial u}}{{\partial t}} = \hat a\frac{{\partial u}}{{\partial x}} + \hat b\frac{{\partial u}}{{\partial y}}.$$ We prove that the stability region of the MacCormack scheme for this equation isexactly given by $$\left( {\hat a\frac{{\Delta _t }}{{\Delta _x }}} \right)^{2/3} + \left( {\hat b\frac{{\Delta _t }}{{\Delta _x }}} \right)^{2/3} \leqslant 1$$ where Δ t , Δ x and Δ y are the grid distances. It is interesting to note that the stability region is identical to the one for Lax-Wendroff scheme proved by Turkel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02253461
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    A parallel algorithm for solving special tridiagonal systems on ring networks (1996)
    Springer
    Computing 56 (1996), S. 385-395 
    Details
    ISSN: 1436-5057
    Keywords: 65F05 ; 15A23 ; nCUBE/2E multiprocessors ; matrix perturbation ; parallel algorithm ; performance ; ring network ; tridiagonal Toeplitz linear systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Wir betrachten die Lösung einer Klasse von speziellen tridiagonalen Gleichungssystemen, die schiefsymmetrische und Töplitz-Systeme einschließt, und geben einen schnellen, parallelen, Algorithmus dafür an. Bei Vorliegen von Diagonal-Dominanz benötigt unser paralleler Solver nur Kommunikation zwischen benachbarten Prozessoren auf einem Ring-Netzwerk. Eine Fehleranalyse wird angegeben. Einige experimentelle Resultate, die auf einem nCUBE/2E Gerät gewonnen wurden, zeigen das gute Verhalten unseres stabilen, parallelen Solvers.
    Notes: Abstract The solution of special linear, circulant-tridiagonal systems is considered. In this paper, a fast parallel algorithm for solving the special tridiagonal systems, which includes the skew-symmetric and tridiagonal-Toeplitz systems, is presented. Employing the diagonally dominant property, our parallel solver does need only local communications between adjacent processors on a ring network. An error analysis is also given. On the nCUBE/2E multiprocessors, some experimental results demonstrate the good performance of our stable parallel solver.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02253462
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Editorial (1996)
    Springer
    AI & society 10 (1996), S. 107-108 
    Details
    ISSN: 1435-5655
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01205276
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    The human-centred movement: The British context (1996)
    Springer
    AI & society 10 (1996), S. 109-126 
    Details
    ISSN: 1435-5655
    Keywords: Humann-centredness ; Human-machine symbiosis ; Information society ; Social innovation ; Rule-following ; Causality ; Human-purpose ; Subsidiarity ; Communitarianism ; Diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The cornerstone of the British human-centred tradition lies in the two notions, human machine symbiosis and socially useful technology. The contemporary tradition has its roots in the LUCAS PLAN of the 1970s and has recently been shaped by a number of European social and technological movements in Scandianvia, Germany, France, Ireland and Italy. The emergence of the information society places the human-centred debate in wider socio-economic and cultural contexts. The paper explores the shaping of the European dimension of the human-centred tradition and proposes a research agenda for social innovation for inclusive information society.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01205277
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Cognitive technology: A new deal in human computer interaction (1996)
    Springer
    AI & society 10 (1996), S. 219-225 
    Details
    ISSN: 1435-5655
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174599
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Design science 97 (1996)
    Springer
    AI & society 10 (1996), S. 199-217 
    Details
    ISSN: 1435-5655
    Keywords: Design ; Design science ; Human-centred systems ; Social shaping of technology ; Design education
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Design of information systems, on the one hand, is often dominated by pure technical considerations of performance, correctness or reliability. On the other hand, sociological analysis of the social impact of information technology is not transfered to operationalised design criteria and to practice. The paper discusses this contradiction and tries to overcome the gap between computer science and social sciences in design by analysing the history of design in architecture and fine arts as well as the approaches of contemporary design-oriented disciplines. Based on this analysis and on the broad discussion about human-centredness, foundations of a new Design Science are outlined. Consequences for the education of computer scientists and software designers are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01205282
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    An analysis of spoken language development among three intellectually disabled adults (1996)
    Springer
    AI & society 10 (1996), S. 259-272 
    Details
    ISSN: 1435-5655
    Keywords: Body movement ; Intellectual disability ; Verbo-tonal system ; Vibrotactile stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Although this study does not directly prove the effects of vibrotactile stimulation and body movements, it does try to exhibit some observable effects on production of connected speech among three intellectually disabled subjects. Analysis of the subjects' utterances seems to show a certain improvement in prosodic features such as rhythmic structures and Fo (fundamental frequency) movement. On the other hand, segmental features like articulation of vowels and consonants remained relatively unchanged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174602
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Cognitive technology and the pragmatics of impossible plans — A study in cognitive prosthetics (1996)
    Springer
    AI & society 10 (1996), S. 273-288 
    Details
    ISSN: 1435-5655
    Keywords: Cognitive ability ; Cognitive prosthetics ; Planning processes ; Pragmatics ; Relevance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Do AI programs just make it quicker and easier for humans to do what they can do already, or can the range of do-able things be extended? This paper suggests that cognitively-oriented technology can make it possible for humans to construct and carry out mental operations, which were previously impossible. Probable constraints upon possible human mental operations are identified and the impact of cognitive technology upon them is evaluated. It is argued that information technology functions as a cognitive prosthetic enhancing human intelligence and planning capabilities. Boundaries and constraints which Kant, Whorf, and many post-modernist theorists have seen as intrinsic to human cognition now cease to apply.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174603
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Pragmatics and presence (1996)
    Springer
    AI & society 10 (1996), S. 309-314 
    Details
    ISSN: 1435-5655
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper considers the potentially important role played by non-verbal communication in constraining pragmatic processing. Attention is paid to claims about the role of emotion in memory encoding and recall, its role in the formulation of plans and goals, and the creation of a shared emotional sense through various interpersonal processes. It is argued that ignoring these factors can lead to pragmatic theories which overestimate the processing demands facing the conversationalist, and that this overestimation will be problematic for any systems which seek to build on these theories in the future.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174606
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    The person-machine confrontation: Investigations into the pragmatics of dialogism (1996)
    Springer
    AI & society 10 (1996), S. 315-332 
    Details
    ISSN: 1435-5655
    Keywords: Communication ; Design ; Dialogism ; Human-Computer Interaction ; Pragmatics ; Reference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Erroneously attributing propositional attitudes (desires, beliefs...) to computational artefacts has become internationally commonplace in the public arena, especially amongst the new generation of non-initiated users. Technology for rendering machines “user-friendly” is often inspired by interpersonal human communication. This calls forth designers to conceptualise a major component of human intelligence: the sense ofcommunicability, and its logical consequences. The inherentincommunicability of machines subsequently causes a shift in design strategy. Though cataloguing components of bouts between person and machine with Speech Act Theory has been popular, I will endeavour to present thesine qua non for their insertion into a larger unit of discourse — their societal embodiment. I shall argue that the so-called “intelligence” of the artificial should to be seenas a purposeful act that is socially generated, because it comes of Man,for Man. Designership will provide the forum for evolving user requirements and interface renewal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174607
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Scandinavian human-centred systems design: Theoretical reflections and challenges (1996)
    Springer
    AI & society 10 (1996), S. 164-180 
    Details
    ISSN: 1435-5655
    Keywords: Human-centredness ; Scandinavian school ; Computer theory ; Research paradigms ; Complexity ; Communication ; Interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Currently there is a clear trend towards questioning the traditional sovereign human self which for two hundred years has had an undisputed central status within European culture and philosophy. This challenges the tradition of anthropocentrism which in a Scandinavian computer science context has had two theoretical foundations: the workoriented design theory represented by the Scandinavian participatory design philosophy, and the idea of the computer to a rather passive medium for human communication. The process, reducing the computer to a rather passive medium for human communication. The paper firstly examines these two theoretical anthropocentric positions. Secondly it outlines the trend towards challenging the status of the human self within different research contexts. This trend represents a challenge for Human-centred systems design. Finally, it discusses the new demands for conceptualising basic IT research phenomena created by this development, with particular focus on the issue of human-centredness as a systems design strategy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01205280
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    The human-centred information society: A community-based approach (1996)
    Springer
    AI & society 10 (1996), S. 181-198 
    Details
    ISSN: 1435-5655
    Keywords: Human-centred ; Information society ; Social cohesion ; Tripartite collaboration ; Democratic participation ; Community telecottages ; Community Teleservice Centres (CTSC)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The paper argues that the human-centred approach should be considered as an alternative to the techno-economic model of the EC information society. This alternative approach should be based on the principles of democratic participation of citizens and social cohesion. Using a community development based approach the paper introduces concepts of partnership, tripartite collaboration and universal participation. Having evaluated a human-centred approach to the information society this is then applied to the results of four case studies of Danish and Swedish community teleservice centres (CTSCs), and the subsequent lessons drawn.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01205281
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Verification of an active control system using temporal process algebra (1996)
    Springer
    Engineering with computers 12 (1996), S. 46-61 
    Details
    ISSN: 1435-5663
    Keywords: Active structural control ; Calculus of communicating systems (CCS) ; Concurrency workbench ; Modechart ; Real-time systems ; Simulation ; Temporal CCS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract In this paper we describe complementary approaches that can be used to ensure the reliability of real-time systems, such as those used in active structural control systems. These approaches include both model-checking and simulation, and are based on a temporal process algebra. We combine these formal methods with a high-level, graphical modeling technique, Modechart, to specify an active structural control system consisting of several processors. Timing requirements on the system are specified and verified with a combination of process algebraic models and modal logic, and various simulation concepts are described for debugging models and for gaining insight into system behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01200261
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Adaptive mesh refinement using piecewise-linear shape functions based on the blending function method (1996)
    Springer
    Engineering with computers 12 (1996), S. 84-93 
    Details
    ISSN: 1435-5663
    Keywords: Adaptive mesh refinement ; Finite element method ; Mesh generation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Use of quadrilateral elements for finite element mesh refinement can lead either to so-called ‘irregular’ meshes or the necessity of adjustments between finer and coarser parts of the mesh necessary. In the case of ‘irregular’ meshes, constraints have to be introduced in order to maintain continuity of the displacements. Introduction of finite elements based on blending function interpolation shape functions using piecewise boundary interpolation avoids these problems. This paper introduces an adaptive refinement procedure for these types of elements. The refinement is anh-method. Error estimation is performed using the Zienkiewicz-Zhu method. The refinement is controlled by a switching function representation. The method is applied to the plane stress problem. Numerical examples are given to show the efficiency of the methodology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01299394
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Parallel three-dimensional mesh generation on distributed memory MIMD computers (1996)
    Springer
    Engineering with computers 12 (1996), S. 94-106 
    Details
    ISSN: 1435-5663
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper discusses the development of an automatic mesh generation technique designed to operate effectively on multiple instruction multiple data (MIMD) parallel computers. The meshing approach is hierarchical, that is, model entities are meshed after their boundaries have been meshed. Focus is on the region meshing step. An octree is constructed to serve as a localization tool and for efficiency. The tree is also key to the efficient parallelization of the meshing process since it supports the distribution of load to processors. The parallel mesh generation procedure repartitions the domain to be meshed and applies on processor face removals until all face removals with local data have been performed. The portion of the domain to be meshed remaining is dynamically repartitioned at the octant level using an Inertial Recursive Bisection method and local face removals are reperformed. Migration of a terminal octant involves migration of the octant data and the octant's mesh faces and/or mesh regions. Results show relatively good speed-ups for parallel face removals on small numbers of processors. Once the three-dimensional mesh has been generated, mesh regions may be scattered across processors. Therefore, a final dynamic repartitioning step is applied at the region level to produce a partition ready for finite element analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01299395
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Adaptive finite element procedures in elasticity and plasticity (1996)
    Springer
    Engineering with computers 12 (1996), S. 120-141 
    Details
    ISSN: 1435-5663
    Keywords: Discontinuous Galerkin ; Error estimation adaptivity ; Postprocessing ; Superconvergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The paper discusses error estimation and h-adaptive finite element procedures for elasticity and plasticity problems. For the spatial discretization error, an enhanced Superconvergent Patch Recovery (SPR) technique which improves the error estimation by including fulfillment of equilibrium and boundary conditions in the smoothing procedure is discussed. It is known that an accurate error estimation on an early stage of analysis results in a more rapid and optimal adaptive process. It is shown that node patches and element patches give similar quality of the postprocessed solution. For dynamic problems, a postprocessed type of error estimate and an adaptive procedure for the semidiscrete finite element method are discussed. It is shown that the procedure is able to update the spatial mesh and the time step size so that both spatial and time discretization errors are controlled within specified tolerances. A time-discontinuous Galerkin method for solving the second-order ordinary differential equations in structural dynamics is also presented. Many advantages of the new approach such as high order accuracy, possibility to filter effects of spurious modes and convenience to apply adaptive analysis are observed. For plasticity problems, some recent work that improved plastic strains and plastic localization is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01299397
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Two and three-quarter dimensional meshing facilitators (1996)
    Springer
    Engineering with computers 12 (1996), S. 144-154 
    Details
    ISSN: 1435-5663
    Keywords: Automatic mesh generation ; Mesh control ; Mapped meshing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract This paper presents generated enhancements for robust ‘two and three-quarter dimensional meshing’, including: (1) automated interval assignment by integer programming for submapped surfaces and volumes, (2) surface submapping, and (3) volume submapping. An introduction to the simplex method, an optimization technique of integer programming, is presented. Simplification of complex geometry is required for the formulation of the integer programming problem. A method of ‘i-j unfolding’ is defined which explains how irregular geometry can be realigned into a simplified form that is suitable for submap interval assignment solutions. Also presented is the processes by which submapping eliminates the decomposition of surface geometry, through a pseudodecomposition process, producing suitable mapped meshes. The process of submapping involves the creation of ‘interpolated virtual edges’, user defined ‘vertex types’ and ‘i-j-k space’ traversals. The creation of ‘interpolated virtual edges’ is the method by which submapping automatically subdivides surface geometry. The ‘interpolated virtual edge’ is formulated according to an interpolation scheme using the node discretization of curves on the surface. User defined ‘vertex types’ allow direct user control of surface decomposition and interval assignment by modifying ‘i-j-k space’ traversals. Volume submapping takes the geometry decomposition to a higher level by using ‘mapped virtual surfaces’ to eliminate decomposition of complex volumes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01198730
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Automatic, parallel and fault tolerant mesh generation from CAD (1996)
    Springer
    Engineering with computers 12 (1996), S. 178-185 
    Details
    ISSN: 1435-5663
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract HEXAR, a new software product developed at Cray Research, Inc., automatically generates good quality meshes directly from surface data produced by computeraided design (CAD) packages. The HEXAR automatic mesh generator is based on a proprietary and parallel algorithm that relies on pattern recognition, local mesh refinement and coarsening, and variational mesh smoothing techniques to create all-hexahedral volume meshes. HEXAR generates grids two to three orders of magnitude faster than current manual approaches. Although approximate by design, the resulting meshes have qualities acceptable by many commercial structural and CFD (computational fluid dynamics) software. HEXAR turns mesh generation into an automatic process for most commercial engineering applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01198733
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Progress in grid generation via the advancing front technique (1996)
    Springer
    Engineering with computers 12 (1996), S. 186-210 
    Details
    ISSN: 1435-5663
    Keywords: Finite elements ; Grid generation ; Tetrahedra ; Unstructured grids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract We describe recent extensions and improvements to the advancing front grid generation technique. These improvements target a range of applicability, speed and user friendliness. The range of applicability is enlarged by the ability to produce volumetric grids around thin surfaces (such as shells, membranes, fabrics or surfaces with cusps), the generation of high aspect ratio grids for Navier-Stokes applications, the generation of higher order triangular and tetrahedral elements, and the generation of quadrilateral and hexahedral elements. Speed improvements are the result of reduced search overheads, as well as vectorization and parallelization. User friendliness is enhanced by the ability to grid directly discrete data and simpler ways of specifying the desired element size and shape in space. Numerous examples are included that demonstrate the versatility and maturity that advancing front grid generators have achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01198734
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    The toughness of cubic graphs (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 17-22 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The toughness of a graphG is the minimum of|S|/k(G − S) over all setsS of vertices such thatk(G − S) ≥ 2. In this paper upper bounds on the toughness of a cubic graph are derived in terms of the independence number and coloring parameters. These are applied to cycle permutation graphs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858441
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    The Ramsey property for collections of sequences not containing all arithmetic progressions (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 149-161 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract A family ℬ of sequences has the Ramsey property if for every positive integerk, there exists a least positive integerf ℬ(k) such that for every 2-coloring of {1,2, ...,f ℬ(k)} there is a monochromatick-term member of ℬ. For fixed integersm 〉 1 and 0 ≤q 〈 m, let ℬq(m) be the collection of those increasing sequences of positive integers {x 1,..., xk} such thatx i+1 − xi ≡ q(modm) for 1 ≤i ≤ k − 1. Fort a fixed positive integer, denote byA t the collection of those arithmetic progressions having constant differencet. Landman and Long showed that for allm ≥ 2 and 1 ≤q 〈 m, ℬ q(m) does not have the Ramsey property, while ℬ q(m) ∪A m does. We extend these results to various finite unions of ℬ q(m) 's andA t 's. We show that for allm ≥ 2, $$ \cup $$ q=1 m−1 ℬq(m) does not have the Ramsey property. We give necessary and sufficient conditions for collections of the form ℬ q(m) ∪ ( $$ \cup $$ t ∈ T A t) to have the Ramsey property. We determine when collections of the form ℬa(m1) ∪ ℬb(m2) have the Ramsey property. We extend this to the study of arbitrary finite unions of ℬq(m)'s. In all cases considered for whichℬ has the Ramsey property, upper bounds are given forf ℬ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858450
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    On the isomorphisms and automorphism groups of circulants (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 179-187 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Denote byC n(S) the circulant graph (or digraph). LetM be a minimal generating element subset ofZ n, the cyclic group of integers modulon, and $$\tilde M = \{ m, - m|m \in M\} $$ In this paper, we discuss the problems about the automorphism group and isomorphisms ofC n(S). When M $$ \subseteq $$ S $$ \subseteq $$ $$\tilde M = \{ m, - m|m \in M\} $$ , we determine the automorphism group ofC n(S) and prove that for any T $$ \subseteq Z_n , C_n (S) \cong C_n (T)$$ if and only ifT = λS, whereλ is an integer relatively prime ton. The automorphism groups and isomorphisms of some other types of circulant graphs (or digraphs) are also considered. In the last section of this paper, we give a relation between the isomorphisms and the automorphism groups of circulants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858452
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Polynomial invariants of graphs II (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 189-198 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Negami and Kawagoe has already defined a polynomial $$\tilde f(G)$$ associated with each graphG as what discriminates graphs more finely than the polynomialf(G) defined by Negami and the Tutte polynomial. In this paper, we shall show that the polynomial $$\tilde f(G)$$ includes potentially the generating function counting the independent sets and the degree sequence of a graphG, which cannot be recognized fromf(G) in general, and discuss on $$\tilde f(T)$$ of treesT with observations by computer experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858453
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    On the chromatic uniqueness of the graphW(n, n − 2, k) (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 221-230 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract This paper shows that the graphW(n, n − 2, k) is chromatically unique for any even integern ≥ 6 and any integerk ≥ 1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858456
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Isoperimetric numbers of graph bundles (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 239-251 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The main aim of this paper is to give some upper and lower bounds for the isoperimetric numbers of graph coverings or graph bundles, with exact values in some special cases. In addition, we show that the isoperimetric number of any covering graph is not greater than that of the base graph. Mohar's theorem for the isoperimetric number of the cartesian product of a graph and a complete graph can be extended to a more general case: The isoperimetric numberi(G × K 2n) of the cartesian product of any graphG and a complete graphK 2n on even vertices is the minimum of the isoperimetric numberi(G) andn, and it is also a sharp lower bound of the isoperimetric numbers of all graph bundles over the graphG with fiberK 2n. Furthermore, ifn ≥ 2i(G) then the isoperimetric number of any graph bundle overG with fibreK n is equal to the isoperimetric numberi(G) ofG.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858458
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    On the connectivity of unit distance graphs (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 295-303 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract For a number fieldK $$ \subseteq $$ ℝ, consider the graphG(Kd), whose vertices are elements ofK d, with an edge between any two points at (Euclidean) distance 1. We show thatG(K2) is not connected whileG(Kd) is connected ford ≥ 5. We also give necessary and sufficient conditions for the connectedness ofG(K3) andG(K4).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858462
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Perfect matchings in regular bipartite graphs (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 327-331 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract P. Hall, [2], gave necessary and sufficient conditions for a bipartite graph to have a perfect matching. Koning, [3], proved that such a graph can be decomposed intok edge-disjoint perfect matchings if and only if it isk-regular. It immediately follows that in ak-regular bipartite graphG, the deletion of any setS of at mostk − 1 edges leaves intact one of those perfect matchings. However, it is not known what happens if we delete more thank − 1 edges. In this paper we give sufficient conditions so that by deleting a setS ofk + r edgesr ≥ 0, stillG − S has a perfect matching. Furthermore we prove that our result, in some sense, is best possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858465
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    A spatial unit-bar-framework which is rigid and triangle-free (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 341-344 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We present an infinitesimally rigid unit-bar-framework in 3-space which contains no triangle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858467
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Maximally non-hamiltonian graphs of girth 7 (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 361-371 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We describe a sufficient condition for graphs used in a construction of Thomassen (which yields hypohamiltonian graphs) to produce maximally non-hamiltonian (MNH) graphs as well. Then we show that the Coxeter graph fulfils this sufficient condition, and thus applying the Thomassen's construction to multiple copies of the Coxeter graph yields infinitely many MNH graphs with girth 7. So far, the Coxeter graph was the only known example of a MNH graph of girth 7; also no MNH graph of girth greater than 7 has been found yet. Finally, the Isaacs' flower snarksJ k for oddk ≥ 5 are shown to fulfil (for certain vertices) this sufficient condition as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858469
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    A family of multiply extended grids (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 283-293 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We construct an infinite family{Γ n}n=5 of finite connected graphsΓ n that are multiple extensions of the well-known “extended grid” discovered in [1] (which is isomorphic toΓ 5). The graphsΓ n are locallyΓ n−1 forn 〉 5, and have the following property: the automorphism groupG(n) ofΓ n permutes transitively the maximal cliques ofΓ n (which aren-cliques) and the stabilizer of somen-cliqueπ ofΓ n inG(n) inducesΣ n on the vertices ofπ. Furthermore we show that the clique complexes of the graphsΓ n are simply connected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858461
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    A finiteness theorem for maximal independent sets (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 321-326 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Denote bymi(G) the number of maximal independent sets ofG. This paper studies the setS(k) of all graphsG withmi(G) = k and without isolated vertices (exceptG ≅ K 1) or duplicated vertices. We determineS(1), S(2), andS(3) and prove that |V(G)| ≤ 2 k−1 +k − 2 for anyG inS(k) andk ≥ 2; consequently,S(k) is finite for anyk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858464
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    The minimum diameter of orientations of complete multipartite graphs (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 333-339 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Given a graphG, letB be the family of strong orientations ofG, and define A pair {p,q} of integers is called aco-pair if 1 ≤p ≤ q ≤ $$\left( {\mathop {\left\lfloor {\frac{1}{2}} \right\rfloor }\limits^p } \right)$$ . A multiset {p, q, r} of positive integers is called aco-triple if {p, q} and {p, r} are co-pairs. LetK(p1, p2,..., pn) denote the completen-partite graph havingp i vertices in theith partite set. In this paper, we show that if {p 1, p2,...,pn} can be partitioned into co-pairs whenn is even, and into co-pairs and a co-triple whenn is odd, thenε(K(p1, p2,..., pn)) = 2 provided that (n,p 1, p2, p3, p4) ≠ (4, 1, 1, 1, 1). This substantially extends a result of Gutin [3] and a result of Koh and Tan [4].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858466
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Minimal colorings for properly colored subgraphs (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 345-360 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We give conditions on the minimum numberk of colors, sufficient for the existence of given types of properly edge-colored subgraphs in ak-edge-colored complete graph. The types of subgraphs we study include families of internally pairwise vertex-disjoint paths with common endpoints, hamiltonian paths and hamiltonian cycles, cycles with a given lower bound of their length, spanning trees, stars, and cliques. Throughout the paper, related conjectures are proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858468
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    On long cycles in a 2-connected bipartite graph (1996)
    Springer
    Graphs and combinatorics 12 (1996), S. 373-384 
    Details
    ISSN: 1435-5914
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Letk be an integer withk ≥ 2. LetG = (A, B; E) be a 2-connected bipartite graph. Supposed(x) + d(y) ≥ k + 1 for every pair of non-adjacent verticesx andy. ThenG contains a cycle of length at leastmin(2a, 2k) wherea = min(|A|,|B|), unlessG is one of some known exceptions. We conjecture that if|A| = |B| andd(x) + d(y) ≥ k + 1 for every pair of non-adjacent verticesx andy withx ∈ A andy ∈ B, thenG contains a cycle of length at leastmin(2a, 2k).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01858470
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Entropy CODEC from behavioral description based LSI-CAD for fully programmable image coding system (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 231-255 
    Details
    ISSN: 1572-8080
    Keywords: image coding ; JPEG ; Huffman coding ; arithmetic coding ; serial bit processing ; high-level design LSI-CAD ; FPGA ; logic synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Entropy coding, as used for lossless compression in image coding, is dominated by serial bit processing on variable wordlength data. Digital signal processors (DSPs), in which pipeline processors play a central role, fail to yield adequate performance for this kind of application. This paper proposes a new approach that fulfills the two requirements for bit processing, the dominant task in entropy coding: high-performance and functional flexibility. This approach is based on Amphibious logic combining a high-level design LSI-CAD system with a functionally reconfigurable Field Programmable Gate Array (FPGA). Functions are programmed via a behavioral description program in a high-level design LSI-CAD system. In order to show the effectiveness of the newly proposed Amphibious logic approach, we designed JPEG-type Huffman and arithmetic CODECs for encoding still images. A comparison with the results of the processing speeds of DSPs and general-purpose microprocessors proves that the Amphibious logic is indeed possible to attain the dual goals of high performance and programmability. The proposed approach can be used to augment a conventional DSP by allocating the functions of numerical processing and bit stream processing, as used in image coding algorithms, between DSPs and FPGAs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00133304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Condensed state spaces for symmetrical Coloured Petri Nets (1996)
    Springer
    Formal methods in system design 9 (1996), S. 7-40 
    Details
    ISSN: 1572-8102
    Keywords: state spaces ; symmetries ; coloured Petri nets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper deals with state spaces. A state space is a directed graph with a node for each reachable state and an arc for each possible state change. We describe how symmetries of the modelled system can be exploited to obtain much more succinct state space analysis. The symmetries induce equivalence classes of states and equivalence classes of state changes. It is then possible to construct a condensed state space where each node represents an equivalence class of states while each arc represents an equivalence class of state changes. Such a condensed state space is often much smaller than the full state space and it is also much faster to construct. Nevertheless, it is possible to use the condensed state space to verify the same kind of behavioural properties as the full state space. hence, we do not lose analytic power. We define state spaces and condensed state spaces for a language called Coloured Petri Nets (CP-nets). This language is in widespread use for the modelling and analysis of concurrent systems. However, our techniques are general and they can be used for many other kinds of labelled transition systems. The paper does not assume that the reader is familiar with CP-nets (or Petri nets in general)—although such knowledge will, of course, be a help. The first four sections of the paper introduce the basic concepts of CP-nets. The next three sections deal with state spaces, condensed state spaces and computer tools for state space analysis. Finally, there is a short conclusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00625967
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Exploiting symmetry in temporal logic model checking (1996)
    Springer
    Formal methods in system design 9 (1996), S. 77-104 
    Details
    ISSN: 1572-8102
    Keywords: model checking ; symmetry ; temporal-logic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In practice, finite state concurrent systems often exhibit considerable symmetry. We investigate techniques for reducing the complexity of temporal logic model checking in the presence of symmetry. In particular, we show that symmetry can frequently be used to reduce the size of the state space that must be explored during model checking. In the past, symmetry has been exploited in computing the set of reachable states of a system when the transition relation is represented explicitly [14, 11, 19]. However, this research did not consider arbitrary temporal properties or the complications that arise when BDDs are used in such procedures. We have formalized what it means for a finite state system to be symmetric and described techniques for reducing such systems when the transition relation is given explicitly in terms of states or symbolically as a BDD. Moreover, we have identified an important class of temporal logic formulas that are preserved under this reduction. Our paper also investigates the complexity of various critical steps, like the computation of the orbit relation, which arise when symmetry is used in this type of verification. Finally, we have tested our ideas on a simple cache-coherency protocol based on the IEEE Futurebus + standard.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00625969
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Regrouping parallel processes (1996)
    Springer
    Formal methods in system design 9 (1996), S. 263-302 
    Details
    ISSN: 1572-8102
    Keywords: correctness preserving transformation ; distributed system ; formal specification ; process algebra ; process network
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Two techniques are introduced for achieving semantics preserving transformations of process interconnection patterns described by algebraic parallel behaviour expressions. The semantic relation to be preserved is strong bisimulation equivalence. Convenient process network representations are identified as unique representatives of equivalence classes of parallel expressions. The first transformation technique is very simple, but can only be applied to a restricted class of expressions. The second technique is general, and achieves the desired process regrouping, whenever it exists, by inscribing the multi-arcs of the underlying process network into the binary syntax tree of a target expression pattern. The described transformation techniques have been implemented in the LOTOS Integrated Tool Environment (LITE) of ESPRIT Project LotoSphere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00122084
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Call for papers (1996)
    Springer
    Formal methods in system design 9 (1996), S. i 
    Details
    ISSN: 1572-8102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00122085
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    A proposal of an ATM wireless access system for tetherless multimedia services (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 335-347 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper proposes an ATM wireless access system for tetherless multimedia services. The proposed system is intended to provide ATM-based high-speed transmission capability for tetherless multimedia services by wireless media in private LAN/WAN environments as well as public environments. To enable high-speed transmission, this paper proposes the utilization of the SHF band taking advantage of its wide frequency spectrum availability. However, the propagation feature of the SHF band limits the wireless terminal mobility in the proposed system compared with current cellular phone systems. This paper discusses the concept and system architecture of the proposed ATM wireless access system, including its ATM transport based on ATM/TDMA conversion using a time stamp scheme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193265
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Better verification through symmetry (1996)
    Springer
    Formal methods in system design 9 (1996), S. 41-75 
    Details
    ISSN: 1572-8102
    Keywords: formal verification ; protocol verification ; hardware description language ; programming language design ; symmetry ; state reduction ; model checking ; cache coherance protocols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A fundamental difficulty in automatic formal verification of finite-state systems is thestate explosion problem—even relatively simple systems can produce very large state spaces, causing great difficulties for methods that rely on explicit state enumeration. We address the problem by exploiting structuralsymmetries in the description of the system to be verified. We make symmetries easy to detect by introducing a new data typescalarset, a finite and unordered set, to our description language. The operations on scalarsets are restricted so that states are guaranteed to have the same future behaviors, up to permutation of the elements of the scalarsets. Using the symmetries implied by scalarsets, a verifier can automatically generate a reduced state space, on the fly. We provide a proof of the soundness of the new symmetry-based verification algorithm based on a definition of the formal semantics of a simple description language with scalarsets. The algorithm has been implemented and evaluated on several realistic high-level designs. Memory requirements were reduced by amounts ranging from 83% to over 99%, with speedups ranging from 65% to 98%. Symmetry-based reduction leads to an alternative characterization ofdata independence: a protocol is data-independent if there is a scalarset type not used as an array index orfor loop index. In this case, symmetry-based reduction converts an infinite state space to a finite state space. Unlike other methods that exploit data independence in verification, this reduction occurs completely automatically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00625968
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    A unified signal transition graph model for asynchronous control circuit synthesis (1996)
    Springer
    Formal methods in system design 9 (1996), S. 139-188 
    Details
    ISSN: 1572-8102
    Keywords: asynchronous circuits ; specification ; hazards ; concurrency ; delay models ; speed-independence ; delay-insensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Characterization of the behavior of an asynchronous system depending on the delay of components and wires is a major task facing designers. Some of these delays are outside the designer's control, and in practice may have to be assumed unbounded. The existing literature offers a number of analysis and specification models, but lacks a unified framework to verify directly if the circuit specification admits a correct implementation under these hypotheses. Our aim is to fill exactly this gap, offering both low-level (analysis-oriented) and high-level (specification-oriented) models for asynchronous circuits and the environment where they operate, together with strong equivalence results between the properties at the two levels. One interesting side result is the precise characterization of classical static and dynamic hazards in terms of our model. Consequently the designer can check the specification and directly decide if the behavior of any implementation will depend, e.g., on the delays of the signals described by such specification. We also outline a design methodology based on our models, pointing out how they can be used to select appropriate high and low-level models depending on the desired characteristics of the system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00122081
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    The incorporation of testing into formal verification: Direct, modular, and hierarchical correctness degrees (1996)
    Springer
    Formal methods in system design 9 (1996), S. 235-261 
    Details
    ISSN: 1572-8102
    Keywords: testing ; verification ; modular ; hierarchical
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We describe a paradigm for the incorporation of software or hardware testing into formal verification and give some preliminary results. The “correctness degree” is essentially the fraction of computations of a program (or other computational description) that satisfy a given specification (this fraction can be weighted to account for a non-uniform distribution of inputs in the application environment.) We give some results about using test sets to establish correctness degrees, and we indicate how to find the correctness degree of a system composed of partially verified, partially tested modules. In addition we discuss how to combine probabilistic correctness results at different levels of abstraction in the computer hierarchy. We believe that this proposed methodology has the potential to help achieve rigorous estimates of correctness in cases that have proven elusive for pure verification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00122083
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    On the models for asynchronous circuit behaviour with OR causality (1996)
    Springer
    Formal methods in system design 9 (1996), S. 189-233 
    Details
    ISSN: 1572-8102
    Keywords: asynchronous circuits ; (AND and OR) causality ; causal logic nets ; change diagrams ; concurrency ; input-output automata ; modeling ; Petn nets ; signal transition graphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Asynchronous circuits behave like concurrent programs implemented in hardware logic. The processes in such circuits are synchronised in accordance with the dynamic logical and causal conditions between switching events. The classical paradigm, easily represented in most process-oriented languages for concurrent systems modelling, is AND causality, which is often associated with a rendez-vous synchronisation. In this paper we investigate a different, less known paradigm, called OR causality. This paradigm is however different from the classical MERGE paradigm, which is based on mutually exclusive events. Petri nets and Change Diagrams provide adequate modelling and circuit synthesis tools for the various OR causality types, yet they do not always bring the specifier to a unique decision about which modelling construct must be used for which type. We present a unified descriptive tool, called Causal Logic Net, which is graphically based on Petri net but has an explicit logic causality annotation for transitions. It is aimed as the least possible generalisation of Petri nets and Change Diagrams. The signal-transition interpretation of this tool is analogous to, but more powerful than, the well-known Signal Transition Graph. A number of examples demonstrate the usefulness of this model in the synthesis of asynchronous control circuits. It is shown that the extension of the basic, unconditional, firing rule with the one that depends upon the marking of the transition preconditions increases the descriptive power of the model to that of the Turing Machine model and allows the modelling of non-commutative state transition behaviour in a purely causal form.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00122082
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Amulti-channel model for initial and handoff accesses in a mobile computing environment (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 17-27 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The communication infrastructure of a mobile computing environment can be based on the structure of a cellular/microcellular telephone system or a PCS network. In such a system, the occurrence of handoffs cannot be avoided and when handoffs occur, wireless links held by mobile computers crossing cell boundaries may be forced to terminate. The probability that a handoff access request will result in forced termination has a significant effect on the performance of a mobile computing environment, as does the probability that an initial access request will be blocked. Although some research has been done on initial and handoff accesses in cellular/microcellular telephone systems and PCS networks, the analytical models used in this research are not appropriate for mobile computing, since unlike a telephone, a mobile computer may use several channels at once. In this paper, we develop an analytical model to study initial and handoff accesses in a mobile computing environment. The model is based on a multi-dimensional continuous time Markov chain. The accuracy of the model is verified by comparison with simulation results. We then use the model to find a practical approach to balancing the initial access blocking probability and avarage forced termination probability of a connection in a mobile computing network.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01342728
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    A survey of routing techniques for mobile communications networks (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 89-104 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Mobile wireless networks pose interesting challenges for routing system design. To produce feasible routes in a mobile wireless network, a routing system must be able to accommodate roving users, changing network topology, and fluctuating link quality. We discuss the impact of node mobility and wireless communication on routing system design, and we survey the set of techniques employed in or proposed for routing in mobile wireless networks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193330
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    A class of mobile motion prediction algorithms for wireless mobile computing and communications (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 113-121 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper describes a class of novel mobile motion prediction algorithms for supporting global mobile data accessing. Traditionally, mobility and routing management includes functions to passively keep track of the location of the users/terminals and to maintain connections to the terminals belonging to the system. To maintain uninterrupted high-quality service for distributed applications, it is important that a mobile system be more intelligent and can anticipate the change of the location of its user. We propose an aggressive mobility and routing management scheme, called predictive mobility management. A class of mobile motion prediction algorithms predicts the “future” location of a mobile user according to the user's movement history, i.e., previous movement patterns. By combining this scheme with mobility agent functions, the service and user routing data are actually pre-connected and pre-assigned at the locations to which the user is moving. Thus, the user can immediately receive service or data with virtually the same efficiency as at the previous location, i.e., without encountering a large “data structure handover” delay before service or data is available.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193332
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Analysis of a mobile-assisted adaptive location management strategy (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 105-112 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Source messages intended for a mobile host can be routed in one of two ways. Either the source knows the direct route to the mobile host, and is informed of all location changes by the mobile host (informed routing), or the source directs messages to a home agent that forwards messages to the mobile host (triangle routing). When the rate at which the mobile host changes location and the rate at which messages are directed to the mobile host are known and fixed, we show that the optimal routing policy is described by a threshold rule that depends on the normalized differential cost of the routing techniques and the ratio of the source messaging to location update rates. Since thiscall to mobility ratio may not be knowna priori or may change slowly with time, we also derive an adaptive policy selection algorithm. The policy is derived from a maximum likelihood estimate of the call to mobility ratio based on observations of message arrivals and location changes. The algorithm is found to work well when there is a clear advantage to either triangle or informed routing. However, when the two routing schemes are relatively close in average cost, the algorithm performance is degraded by repeated policy reversals. For this reason, algorithms which use hysteresis and/or a preset preference (preference threshold) for one routing scheme or another were explored. It was found that neither hysteresis, nor preference threshold techniques alone performed well, but rather a combination of the two resulted in greatly improved performance for a wide range of values of the call to mobility ratio.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193331
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Challenges for nomadic computing: Mobility management and wireless communications (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 3-16 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper, we present several challenges and innovative approaches to support nomadic computing. The nomadic computing environment is characterized by mobile users that may be connected to the network via wired or wireless means, many of whom will maintain only intermittent connectivity with the network. Furthermore, those accessing the network via wireless links will contend with limitations of the wireless media. We consider three general techniques for addressing these challenges: (1) asymmetric design of applications and protocols, (2) the use of network-based proxies which perform complex functions on behalf of mobile users, and (3) the use of pre-fetching and caching of critical data. We examine how these techniques have been applied to several systems, and present results in an attempt to quantify their relative effectiveness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01342727
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Editorial (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 233-234 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193257
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Forward error control for MPEG-2 video transport in a wireless ATM LAN (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 245-257 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The possibility of providing multimedia services to mobile users has led to interest in designing broadband wireless networks that can guarantee quality of service for traffic flows. However, a fundamental problem in these networks is that severe losses may occur due to the random fading characteristics of the wireless channel. Error control algorithms which compensate for these losses are required in order to achieve reasonable loss rates. In this paper, the performance of error control based on forward error correction (FEC) for MPEG-2 video transmission in an indoor wireless ATM LAN is studied. A random bit error model and a multipath fading model are used to investigate the effect of errors on video transport. Combined source and channel coding techniques that employ single-layer and scalable MPEG-2 coding to combat channel errors are compared. Simulation results indicate that FEC-based error control in combination with 2-layer video coding techniques can lead to acceptable quality for indoor wireless ATM video.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193259
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Lossless handover for wireless ATM (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 299-312 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Handover is one of the key research topics for the emerging wireless ATM networks. This paper describes a handover mechanism for intra-switch handovers for wireless ATM. The handover procedure is simple enough to be implementable as a limited enhancement to ATM switch platforms for fixed network, yet provides low delay and lossless handover when used together with a suitable radio interface. The paper also reports on initial simulation result.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193263
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Probability models of microcell coverage (1996)
    Springer
    Wireless networks 2 (1996), S. 289-296 
    Details
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract Once a subscriber unit served by a microcell initiates a call, it must remain in the coverage area of the microcell long enough to complete call set up and hand-off functions. This restricts the minimum size attainable by a microcell. This paper derives the relationship between the microcell size, the call processing time, and the probability that a subscriber unit, initiating a call, will remain inside the microcell coverage area for at least the duration of call processing. Under simple assumptions, time spent in the coverage area of the microcellbefore andafter call initiation have the same cumulative density function, which is derived in this paper for traffic conditions encountered in highway and metropolitan settings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01262048
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    DS/CDMAM-ary orthogonal signalling in a shadowed Rayleigh channel for mobile communications (1996)
    Springer
    Wireless networks 2 (1996), S. 343-357 
    Details
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract In this paper a modified RAKE receiver is studied for a frequency selective mobile radio channel. The reverse link (Mobile to base station) is analysed, assuming lognormal shadowing and Rayleigh fading andK asynchronous users, withM orthogonal sequences per user. The analysis is based on the consideration of the quadrature components of the signal and noise, taking advantage of the multipath effects. The performance evaluation is carried out in terms of both the bit error rate and outage probability in order to qualify completely the proposed receiver. The positive results assure the possibility of applying this system in a microcellular mobile radio environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01262052
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    A comprehensive model for voice activity in conversational speech-development and application to performance analysis of new-generation wireless communication systems (1996)
    Springer
    Wireless networks 2 (1996), S. 359-367 
    Details
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract Proposed new wireless communication systems such as third generation cellular and PCN will utilize speech inferpolation, disconnecting the user from the spectral resource during pauses in speech in order to reduce radiated emissions and improve spectral efficiency. An accurate model of the on-off characteristics of conversational speech is thus necessary to analyze system performance, particularly if the system utilizes a time and/or frequency division multiple access technique. Previously developed speech activity models are deficient because they either do not reproduce short silent pauses of less than 200 ms. (representative of the silence gaps between syllables or words) or else they do not replicate the dynamics between the two conversing parties. Starting with the P.T. Brady model and developing appropriate modifications, this paper formulates a simple, accurate, comprehensive 8-state Markov model for voice activity in conversational speech. The new model can easily be incorporated into simulations or analyses assessing the performance of various new-generation wireless networks, thus improving the accuracy of the performance assessments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01262053
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Editorial (1996)
    Springer
    Wireless networks 2 (1996), S. 161-162 
    Details
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01201050
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    QoS provisioning in micro-cellular networks supporting multiple classes of traffic (1996)
    Springer
    Wireless networks 2 (1996), S. 195-203 
    Details
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract We introduce an adaptive call admission control mechanism for wireless/mobile networks supporting multiple classes of traffic, and discuss a number of resource sharing schemes which can be used to allocate wireless bandwidth to different classes of traffic. The adaptive call admission control reacts to changing new call arrival rates, and the resource sharing mechanism reacts to rapidly changing traffic conditions in every radio cell due to mobility of mobile users. In addition, we have provided an analytical methodology which shows that the combination of the call admission control and the resource sharing schemes guarantees a predefined quality-of-service to each class of traffic. One major advantage of our approach is that it can be performed in a distributed fashion removing any bottlenecks that might arise due to frequent invocation of network call control functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01201053
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Transmission of video telephony images over wireless channels (1996)
    Springer
    Wireless networks 2 (1996), S. 219-228 
    Details
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Notes: Abstract In this paper, the effects of digital transmission errors on H.263 codecs are analyzed and the transmission of H.263 coded video over a TDMA radio link is investigated. The impact of channel coding and interleaving on video transmission quality is simulated for different channel conditions. Fading on radio channels causes significant transmission errors and H.263 coded bit streams are very vulnerable to erros. Powerful Forward Error Correction (FEC) codes are therefore necessary to protect the data so that it can be successfully transmitted at acceptable signal power levels. FEC, however, imposes a high bandwidth overhead. In order to make best use of the available channel bandwidth and to alleviate the overall impact of errors on the video sequence, a twolayer data partitioning and unequal error protection scheme based on H.263 is also studied. The scheme can tolerate more transmission errors and leads to more graceful degradation in quality when the channel SNR decreases. In lossy environments, it can improve the video transmission quality at no extra bandwidth cost.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01201055
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Editorial (1996)
    Springer
    Wireless networks 2 (1996), S. 263-264 
    Details
    ISSN: 1572-8196
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01262045
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Message from the editors-in-chief (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 3-3 
    Details
    ISSN: 1572-8080
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00134681
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Embedded system design (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 5-50 
    Details
    ISSN: 1572-8080
    Keywords: System Design ; HW/SW codesign ; Video processing ; Automotive electronics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In the past decade the main engine of electronic design automation has been the widespread application of ASICs (Application Specific Integrated Circuits). Present technology supports complete systems on a chip, most often used as so-called embedded systems in an increasing number of applications. Embedded systems pose new design challenges which we believe will be the driving forces of design automation in the years to come. These include the design of electronic systems hardware, embedded software and hardware / software codesign. This paper explores the novel technical challenges in embedded system design and presents experiences and results of the work in this area using the CASTLE system. CASTLE supports the design of complex embedded systems and the design of the required tools. It provides a central design representation, Verilog, VHDL and C/C++ frontends, Hardware generation in VHDL and BLIF, a retargetable compiler backend and several analysis and visualization tools. Two design examples, video compression and a diesel injection control, illustrate the presented concepts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00134682
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    A co-synthesis approach to embedded system design automation (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 69-120 
    Details
    ISSN: 1572-8080
    Keywords: Embedded system co-synthesis ; Constraint analysis ; Multithreading for embedded systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Embedded systems are targeted for specific applications under constraints on relative timing of their actions. For such systems, the use of pre-designed reprogrammable components such as microprocessors provides an effective way to reduce system cost by implementing part of the functionality as a program running on the processor. However, dedicated hardware is often necessary to achieve the requisite timing performance. Analysis of timing constraints is, therefore, key to determination of an efficient hardware-software implementation. In this paper, we present a methodology for embedded system design as a co-synthesis of interacting hardware and software components. We present a decomposition of the co-synthesis problem into sub-problems, that is useful in building a framework for embedded system CAD. In particular, we present operation-level timing constraints and develop the notion of satisfiability of constraints by a given implementation both in the deterministic and probabilistic sense. Constraint satisfiability analysis is then used to define hardware and software portions of functionality. We describe algorithms and techniques used in developing a practical co-synthesis framework, vulcan. Examples are presented to show the utility of our approach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00134684
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Codesign analysis of a computer graphics application (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 121-145 
    Details
    ISSN: 1572-8080
    Keywords: Codesign ; Analysis ; Speed-up ; Cosimulation ; Computer Graphics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper describes a codesign case study where a computer graphics application is examined with the intention to speed up its execution. The application is specified as a C program, and is characterized by the lack of a simple compute-intensive kernel. The hardware/software partitioning is based on information obtained from software profiling and the resulting design is validated through cosimulation. The achieved speed-up is estimated based on an analysis of profiling information from different sets of input data and various architectural options.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00134685
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    A case study in computer-aided co-design of embedded controllers (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 51-67 
    Details
    ISSN: 1572-8080
    Keywords: hardware/software co-design ; software synthesis ; hardware synthesis ; formal verification ; Finite ; State Machine representation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We present an application of the methodology and of the various software tools embedded in the POLIS co-design system. The application is in the realm of automotive electronics: a shock absorber controller, whose specification comes from an actual product. All aspects of the design process are closely examined, including high level language specification and automatic hardware and software synthesis. We analyze different software implementation styles, compare the results, and outline the future developments of our work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00134683
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Codesign of a parallel architecture and an optimizing compiler backend: SIN rete processing as a case study (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 147-176 
    Details
    ISSN: 1572-8080
    Keywords: programmable application-specific hardware ; mixed hardware/software implementation ; fine-grain parallelism ; performance/cost of operations ; application-specific code
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The move towards higher levels of abstraction in hardware design begins to blur the difference between hardware and software design. Nevertheless, the attractiveness of a software implementation is still defined by the much smaller abstraction gap between specification and implementation. Whereas, hardware design creates the possibility to exploit parallelism at a very fine level of granularity and thereby achieve tremendous performance gains with a moderate expenditure of hardware. This paper describes the joint design process leading to an ASIC chipset accelerating the execution of rulebased systems. The interaction between the algorithm used for software implementation and the parallel algorithm suited for hardware implementation is examined. An area efficient implementation of the programmable hardware was enabled by an application specific compiler backend. The heuristics applied by the optimising “code” generator are discussed quantitatively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00134686
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    A CoDesign case study with the MCSE methodology (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 183-212 
    Details
    ISSN: 1572-8080
    Keywords: Embedded systems ; system design methodolgy ; functional design ; CoDesign
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper, we describe the experiment of a CoDesign process to develop a communication system which needs to correctly mix hardware and software parts in order to satisfy the various required performances. The system design process is based on the MCSE methodology and we show its usefulness for CoDesign. CoDesign is shown as an enhancement of the implementation specification step of MCSE. System partitioning is the result of an interactive procedure based on performance and cost evaluations. The complete description of the implementation is obtained by transformations of the functional description: C or C++ for the software, VHDL for the hardware. The links between hardware and software are also synthesized. Such a procedure and associated tools aim at obtaining system prototypes in an efficient and incremental manner. The described example illustrates the benefit of the proposed method, the significance of the functional level and the specific part of a whole system for which CoDesign is appropriate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00133302
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    A survey on estimating the timing constraints of hard real-time systems (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 213-230 
    Details
    ISSN: 1572-8080
    Keywords: Real-time systems ; deadline estimation and characterisation ; timeliness of control services ; computer controlled systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A real-time computer system must interact with its environment in terms that are dictated by the occurrence of a significant event or simply by the passage of time. The computational activities triggered by these stimuli are expected to provide the correct results at the right time, since a real-time controller must meet the timing constraints that are dictated by its particular environment. If a computer controller fails to meet these time constraints, the controlled system may suffer a behavioural degradation from where, in some cases, a catastrophe can emerge. Thus, the correct estimation and handling of the timing constraints of a controlled system are central issues for the specification, development and test of a real-time computer controller, in a job that requires the scientific contribution of system engineers and real-time computer designers. In this paper we survey proposed solutions and concepts for estimating the timing constraints and the behavioural degradation of a controlled system when it suffers the impact of a timing failure. Although it is universally agreed that these are central issues for the development of predictable real-time controllers, this study shows that, except for a few cases, current literature does not place on them as much emphasis as one could expect. Moreover, a systematic method for evaluating the timing constraints of a controlled system does not seem to actually exist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00133303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Co-synthesis and co-simulation of control-dominated embedded systems (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 257-289 
    Details
    ISSN: 1572-8080
    Keywords: Control dominated systems ; hw-sw co-design ; application-specific software synthesis ; real-time process scheduling ; hw-sw cosimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper presents a methodology for hardware/software co-design with particular emphasis on the problems related to the concurrent simulation and synthesis of hardware and software parts of the overall system. The proposed approach aims at overcoming the problem of having two separate simulation environments by defining a VHDL-based modeling strategy for software execution, thus enabling the simulation of hardware and software modules within the same VHDL-based CAD framework. The proposed methodology is oriented towards the application field of control-dominated embedded systems implemented onto a single chip.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00133305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Lessons from the design of a PC-based private branch exchange (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 297-313 
    Details
    ISSN: 1572-8080
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We designed TigerSwitch, a digital private branch exchange (PBX) implemented on an IBM PC-compatible platform, as an experiment in embedded system design. A telephone switching system is an interesting example of embedded system co-design because it combines a rich functionality with deadlines ranging from seconds to tenths of a millisecond. This paper uses design decisions from TigerSwitch to illustrate the difficulties faced in the partitioning and allocation of a system specification into an architecture: the critical performance paths may not be obvious from the initial specification, and it is often difficult to obtain the performance data required to allocate functions in the architecture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209907
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Issues for low-power CAD tools: A system-level design study (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 315-332 
    Details
    ISSN: 1572-8080
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A case study in low-power system-level design is presented. We detail the design of a low-power embedded system, a touchscreen interface device for a personal computer. This device is designed to operate on excess power provided by unused RS232 communication lines. We focus on the design and measurement procedures used to reduce the power requirements of this system to less than 50 mW. Additionally, we highlight opportunities to use system-level design and analysis tools for low-power design and the obstacles that prevented using such tools in this design.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209908
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    CoWare—A design environment for heterogeneous hardware/software systems (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 357-386 
    Details
    ISSN: 1572-8080
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper addresses CoWare: an environment for design of heterogeneous systems on chip. These systems are heterogeneous both in terms of specification and implementation. CoWare is based on a communicating processes data-model which supports encapsulation and refinement and makes a strict separation between functional and communication behaviour. Encapsulation enables the reuse of existing specification and design environments (languages, simulators, compilers). Refinement provides for a consistent and integrated path from specification to implementation. The design steps that will be addressed include: system specification, simulation at various abstraction levels, data path synthesis, communication refinement and hardware/software co-design. A spread-spectrum based pager system serves to illuminate the design process in the CoWare environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209910
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Lower bounds on the iteration time and the initiation interval of functional pipelining and loop folding (1996)
    Springer
    Design automation for embedded systems 1 (1996), S. 333-355 
    Details
    ISSN: 1572-8080
    Keywords: High level synthesis ; performance estimation ; pipelined circuits and loop scheduling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The performance of pipelined datapath implementations is measured basically by three parameters: the clock cycle length, the initiation interval between successive iterations (inverse of the throughput) and the iteration time (turn-around time). In this paper we present a new method for computing performance bounds of pipelined implementations: • Given an iterative behavior, a set of resource constraints and a target initiation interval, we derive a lower bound on the iteration time achievable by any pipelined implementation. • Given an iterative behavior and a set of resource constraints, we derive a lower bound on the initiation interval achievable by any pipelined implementation. The method has a low complexity and it handles behavioral specifications containing loop statements with interiteration data dependency and timing constraints.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209909
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    On a class of optimal abstractions of finite-state machines (1996)
    Springer
    Formal methods in system design 8 (1996), S. 195-220 
    Details
    ISSN: 1572-8102
    Keywords: finite-state machine ; monitoring ; faults ; abstraction ; optimal partitioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Anabstraction A of an fsmM consists in partitioning its states, inputs, and outputs into groups, thus turning it into a non-deterministic fsmM A. For fixed sets of states, inputs, and outputs, and abstraction generally maps a number of machinesM defined on these sets into the sameM A. We would like to find anoptimal abstractionA * which minimizes this number, while lumping the states, inputs, and outputs into a specified number of classes. We extend these ideas to an fsmM operating in a random environment, and show that the abstraction results in a probabilistic fsm $$\mathcal{M}_A $$ . Thinking of changes inM's output map as resulting in machinesM≠MM, we want to find anA * that minimizes the number ofMM which are such that the transition probabilities of their abstracted version are identical to those of the specification machine $$\mathcal{M}_A $$ . SuchMM arise from statistically-undetectable output faults inM. Abstractions are directly applicable to the monitoring of a complex system by an observer for deviations from correct behavior (faults). Complex systems are usually accessible through restricted interfaces, which do not allow the observer to distinguish among all states, inputs, and outputs, thus rendering some faulty transitions undetectable. An optimal interface design will minimize the number of such undetectable faults. Assuming that only single-transition output faults occur inM, we show that each of the classes into which the abstraction lumps the outputs contributes a number of undetectable output faults. We then show that the problem of partitioning the outputs into a given number of classes that minimizes the maximum of these numbers is NP-complete. However, we give (a) an approximate minimization algorithm, running in time linear in the number of classes and quadratic in the number ofM's outputs, and (b) a lower bound on the minimum, computable in the same amount of time. The concept of optimal abstractions is illustrated by numerical results on combinational logic circuits that perform arithmetical operations. The results shed light on the trade-off between model simplification and the ability to detect erroneous behaviors in complex systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00709137
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Experiences with software specification and verification using LP, the Larch proof assistant (1996)
    Springer
    Formal methods in system design 8 (1996), S. 221-272 
    Details
    ISSN: 1572-8102
    Keywords: formal specification ; machine supported verification ; Larch ; formal methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We sketch a method for deduction-oriented software and system development. The method incorporates formal machine-supported specification and verification as activities in software and systems development. We describe experiences in applying this method. These experiences have been gained by using the LP, the Larch proof assistant, as a tool for a number of small and medium size case studies for the formal development of software and systems. LP is used for the verification of the development steps. These case studies include • quicksort • the majority vote problem • code generation by a compiler and its correctness • an interactive queue and its refinement into a network. The developments range over levels of requirement specifications, designs and abstract implementations. The main issues are questions of a development method and how to make good use of a formal tool like LP in a goal-directed way within the development. We further discuss the value of advanced specification techniques, most of which are deliberately not supported by LP and its notation, and their significance in development, Furthermore, we discuss issues of enhancement of a support system like LP and the value and the practicability of using formal techniques such as specification and verification in the development process in practice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00709138
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Topology-based tracking strategies for personal communication networks (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 49-56 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper explores tracking strategies for mobile users in personal communication networks which are based on thetopology of the cells. We introduce the notion oftopology-based strategies in a very general form. In particular, the known paging areas, overlapping paging areas, reporting centers, and distance-based strategies are covered by this notion. We then compare two topology-based strategies with the time-based strategy on the line and mesh cell topology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01342731
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Editorial (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 87-88 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193329
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Mobile ATM buffer capacity analysis (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 67-73 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper extends a stochastic theory for buffer fill distribution for multiple “on” and “off” sources to a mobile environment. Queue fill distribution is described by a set of differential equations assuming sources alternate asynchronously between exponentially distributed periods in “on” and “off” states. This paper includes the probabilities that mobile sources have links to a given queue. The sources represent mobile user nodes, and the queue represents the capacity of a switch. This paper presents a method of analysis which uses mobile parameters such as speed, call rates per unit area, cell area, and call duration and determines queue fill distribution at the ATM cell level. The analytic results are compared with simulation results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01342733
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Traffic-based performance comparison of mobile support strategies (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 57-65 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper presents performance comparison among five strategies for mobile support. The major facilities, that are required for a network protocol to support mobile hosts are location management and packet forwarding. Based on this observation, we consider five basic strategies which use distinct methods to achieve these facilities and compare their performance. These five strategies are Broadcast Notification (BN), Broadcast Forwarding (BF), Broadcast Query (BQ), Default Forwarding (DF), and Default Query (DQ). As a result of analytical evaluation and comparison, it is shown that under different network conditions, such as number of routers, network topology, migration/communication ratio, data/control packet size ratio, different strategies produce minimum network traffic. In short, DF and DQ show the best performance in network size scaling, while BF and BQ are efficient for frequent migration. On the other hand, BN is suitable for a small network which has hosts with infrequent migration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01342732
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    An architecture for mobile radio networks with dynamically changing topology using virtual subnets (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 75-86 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract An architecture adaptabie to dynamic topology changes in multi-hop mobile radio networks is described. The architecture partitions a mobile network into logically independent subnetworks. Network nodes are members of physical and virtual subnets and may change their affiliation with these subnets due to their mobility. Each node is allocated an address based on its current subnet affiliation. We observe-especially in large networks with random topology-that partitioning of the network may result in significantly more balanced load than in one large multi-hop network, an attribute that can significantly improve the network's performance. The architecture is highly fault-tolerant, has a relatively simple location updating and tracking scheme, and by virtue of its load balancing feature, typically achieves a network with relatively high throughput and low delay. The addressing method, logical topology, mobility management and routing procedure are described, and network performance is evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01342734
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Connection architecture and protocols to support efficient handoffs over an ATM/B-ISDN personal communications network (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 123-139 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The next generation personal communication network will likely internetwork wireless networks via the ATM/B-ISDN to enable ubiquitous broadband personal communication services. Support of user terminal mobility, particularly the capability for fast and seamless handoffs, over the ATM/B-ISDN is an expected requirement that is not currently met. We propose extensions to the ATM/B-ISDN user transport and signaling network architectures and signaling protocols to meet these requirements. The new architecture employs the Mobile Virtual Circuit (MVC), a dynamic connection tree in which routes are predetermined but not set up for potential handoff connections. During a handoff, associated signaling using source-routing with a new robust adaptation feature is employed for fast resource allocation to establish the handoff connection by distributed control. We also address the new problem of packet ordering synchronization to enable a seamless handoff. The connection tree reconfigures after each handoff to enable continuous support of successive handoffs. The proposed scheme optimizes handoff delay over the ATM/B-ISDN while minimizing unnecessary resource allocation, chances of handoff failure, and call processing load in the intelligent network, and the extensions are backward compatible to current ATM/B-ISDN standards and implementations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193333
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Crossover switch discovery for wireless ATM LANs (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 141-165 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The emergence of Wireless Local Area Networks (WLANs) has brought about the possibility of mobile computing. In order to maintain connectivity to Mobile Hosts (MHs), a handover mechanism is needed as MHs migrate from one Base Station's (BS) wireless cell to another. Current handover schemes are mainly catered for connectionless WLANs (example Mobile IP) which do not have the ability to support Quality of Service (QoS) for continuous media traffic. Hence, mobility for connection-oriented WLANs (example Wireless ATM) should be considered. The problem faced in a connection-oriented WLAN is the ability to provide a fast, efficient and continuous handover mechanism. Mechanisms that can meet most of these requirements are the Incremental and Multicast Based Re-establishment handover schemes. In particular, the incremental re-establishment scheme relies on the presence of a ‘Crossover Switch’ (CX) to establish the new partial circuits to the new BS. In this paper, five CX discovery schemes are proposed to compute and select the optimised new partial path such that both the set-up latency and network resource consumption associated with the handover are small. The proposed CX discovery schemes (Loose Select, Prior Path Knowledge, Prior Path Optimal, Distributed Hunt and Backward Tracking) are suitable for wireless ATM LANs employing either the centralised or distributed connection management approach with either distance-vector or link-state-like minimumhop routing schemes. Simulation results obtained from a trace-driven mobile network simulator on four different network topologies (Random, Star, Tree and Hierarchical Redundancy) reveal that the Prior Path Knowledge and Distributed Hunt discoveries outperform the other schemes in various aspects. Finally, using the IBM PARIS Gigabit Network as an example, we show how CX discovery is incorporated with routing, connection management and QoS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193334
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    An efficient routing protocol for wireless networks (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 183-197 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We present the Wireless Routing Protocol (WRP). In WRP, routing nodes communicate the distance and secondto-last hop for each destination. WRP reduces the number of cases in which a temporary routing loop can occur, which accounts for its fast convergence properties. A detailed proof of correctness is presented and its performance is compared by simulation with the performance of the distributed Bellman-Ford Algorithm (DBF), DUAL (a loop-free distance-vector algorithm) and an Ideal Link-state Algorithm (ILS), which represent the state of the art of internet routing. The simulation results indicate that WRP is the most efficient of the alternatives analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193336
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    A simple and efficient routing protocol for the UMTSA Access network (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 167-181 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper presents a simple network layer protocol that integrates routing and connectionless transfer of data in a wireless environment. The protocol is specifically geared towards supporting transfer of signalling in mobile networks based on a rooted tree topology. Exploiting the special characteristics of such a topology allows the specification of a very simple and processing efficient routing function. Using the routing function, a connectionless message transport service is implemented. The connectionless transport service is comparable to that of typical network layer protocols of existing data networks. The protocol has originally been specified to carry signalling messages in the control plane of mobile, cellular systems but has the potential to be used also in other environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193335
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Efficient solutions to multicast routing in communication networks (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 221-232 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract An important problem in both wireless and wired communication networks is to be able to efficiently multicst information to a group of network sites. Multicasting reduces the transmission overhead of both wireless and wired networks and the time it takes for all the nodes in the subset to receive the information. Since transmission bandwidth is a scarce commodity especially in wireless networks, efficient and near minimum-cost multicast algorithms are particularly useful in the wireless context. In this paper, we discuss methods of establishing efficient and near minimum-cost multicast routing in communication networks. In particular, we discuss an efficient implementation of a widely used multicast routing method which can construct a multicast tree with a cost no greater than twice the cost of an optimal tree. We also present two efficient multicast tree constructions for a general version of the multicast routing problem in which a network consists of different classes of nodes, where each class can have one or more nodes of the same characteristic which is different from the characteristics of nodes from other classes. Because of their efficient running times, these multicast routing methods are particularly useful in the mobile communication environments where topology changes will imply recomputation of the multicast trees. Furthermore, the proposed efficient and near minimum-cost multicast routing methods are particularly suited to the wireless communication environments, where transmission bandwidth is more scarce than wired communication environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193338
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    A multiple access scheme for multimedia traffic in wireless ATM (1996)
    Springer
    Mobile networks and applications 1 (1996), S. 259-272 
    Details
    ISSN: 1572-8153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper proposes a multiple access scheme for the forthcoming wireless ATM (Asynchronous Transfer Mode) system. Such ATM compatible wireless systems are motivated by the rapidly increasing demand for wireless extensions to broadband networks, which are expected to support mixed broadband services including Constant Bit Rate (CBR), Variable Bit Rate (VBR), and Available Bit Rate (ABR) traffic. Since these different traffics have very different performance requirements, the multiple access scheme design is very challenging. In this paper, we propose a multiple access scheme called Dynamic Time Division Multiple Access with Piggybacked Reservation (DTDMA/PR), attempting to achieve higher statistical multiplexing efficiency in the mixed VBR/CBR/ABR traffic scenario. The basic idea is to exploit two levels of reservation. The first level deals with the isochronous nature of CBR and VBR traffic and the bursty nature of ABR traffic by using the ALOHA reservation procedure. The second level exploits the piggybacked reservation approach to cope with the dynamic feature of VBR traffic in order to increase the multiplexing efficiency. An analytical model is also developed in this paper and verified by simulation. Numerical examples are given to gain some insight into the protocol itself.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193260
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Applying formal verification to the AAMP5 microprocessor: A case study in the industrial use of formal methods (1996)
    Springer
    Formal methods in system design 8 (1996), S. 153-188 
    Details
    ISSN: 1572-8102
    Keywords: formal methods ; formal verification ; microprocessor verification ; microcode verification ; hardware verification systems ; safety critical systems ; PVS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Formal specification combined with mechanical verification is a promising approach for achieving the extremely high levels of assurance required of safety-critical digital systems. However, many questions remain regarding their use in practice: Can these techniques scale up to industrial systems, where are they likely to be useful, and how should industry go about incorporating them into practice? This paper discusses a project undertaken to answer some of these questions, the formal verification of the microcode in the AAMP5 microprocessor. This project consisted of formally specifying in the PVS language a Rockwell proprietary microprocessor at both the instruction-set and register-transfer levels and using the PVS theorem prover to show the microcode correctly implemented the instruction-level specification for a representative subset of instructions. Notable aspects of this project include the use of a formal specification language by practicing hardware and software engineers, the integration of traditional inspections with formal specifications, and the use of a mechanical theorem prover to verify a portion of a commercial, pipelined microprocessor that was not explicitly designed for formal verification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00122419
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Editorial for special issue on symmetry in automatic verification (1996)
    Springer
    Formal methods in system design 9 (1996), S. 5-6 
    Details
    ISSN: 1572-8102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00625966
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...