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  • Articles  (115)
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  • Springer  (115)
  • American Geophysical Union
  • American Institute of Physics (AIP)
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  • 1
    Electronic Resource
    Electronic Resource
    Rehabilitation and replacement of water distribution system components considering uncertainties (1990)
    Springer
    Stochastic environmental research and risk assessment 4 (1990), S. 277-294 
    Details
    ISSN: 1436-3259
    Keywords: Water distribution ; optimization ; nonlinear programming ; integer programming ; chance constraints ; rehabilation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract This paper presents the mathematical development of an integer — nonlinear programming chance — constrained optimization model for the minimum cost rehabilitation/replacement of water distribution system components. Particular attention is given to the handling of uncertainties in the roughness factors and the loading conditions including both the random demand and preassure head requirements. The advantages of the proposed model include the ability to: 1) handle the optimal timing of rehabilitation/replacement for water distribution system components; 2) link a mixed-integer linear program solver, a nonlinear program solver, and a hydraulic simulator into an optimization framework; 3) handle the uncertainties of some of the variables; 4) incorporate various kinds of cost functions; and 5) handle multiple loading conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01544082
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  • 2
    Electronic Resource
    Electronic Resource
    Optimal schedule for cancer chemotherapy (1991)
    Springer
    Mathematical programming 52 (1991), S. 11-17 
    Details
    ISSN: 1436-4646
    Keywords: Modeling ; cancer ; optimization ; optimal control ; drug delivery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this paper we consider the problems of modeling the tumor growth and optimize the chemotherapy treatment. A biologically based model is used with the goal of solving an optimization problem involving discrete delivery of antineoplastic drugs. Our model is formulated via compartmental analysis in order to take into account the cell cycle. The cost functional measures not only the final size of the tumor but also the total amount of drug delivered. We propose an algorithm based on the discrete maximum principle to solve the optimal drug schedule problem. Our numerical results show nice interpretations from the medical point of view.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01582876
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  • 3
    Electronic Resource
    Electronic Resource
    Optimum-Simulation von Ernteprozessen (1994)
    Springer
    OR spectrum 15 (1994), S. 235-246 
    Details
    ISSN: 1436-6304
    Keywords: Simulation ; Optimierung ; Ernteprozeß ; Bedienungsprozeß ; räumliche Aspekte ; Einflußgröße ; Zielgröße ; Bewertungsprozeß ; Simulation ; optimization ; harvesting process ; operational process ; spacious aspects ; influence factor ; target value ; valuation process
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Abstract There is a wide range of possibilities for optimizing harvest process as transport-connected operations in a flow system. They are multi-stage operating process charakterized by a mixed arrangement of the operating elements. Above that, they have distinct spacious aspects. It is demonstrated which charakteristics of such processes have to be simulated by models, what target values should be determined in dependence on which influence factors and under which operational conditions. Furthermore it is elucidated how the valuation process for obtaining the desired information has to be shaped.
    Notes: Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses „Mähdrusch, Körnertransport und -abnahme“ — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01719455
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  • 4
    Electronic Resource
    Electronic Resource
    Obtaining minimum-correlation Latin Hypercube Sampling plans using an IP-based heuristic (1995)
    Springer
    OR spectrum 17 (1995), S. 139-148 
    Details
    ISSN: 1436-6304
    Keywords: Assignment problem ; computer models ; distribution sampling ; estimation ; integer programming ; large-scale modelling ; Latin hypercube ; optimization ; sampling ; sensitivity analysis ; Stichprobenverfahren ; Permutationsmatrizen ; implizite Funktionen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Zusammenfassung Lateinische Hyperwürfel Stichprobenverfahren (LHS) dienen dazu, in geeigneter Weise die Verteilungsfunktion (zumindest angenähert) der Funktionswerte einer komplexen (impliziten) Funktion, in Abhängigkeit ihrer Variablen werte, zu schätzen. Anwendungen finden sich in Modellen, in denen erforderliche Variablenumformungen nicht möglich sind und in denen die Zahl der Simulationsläufe aus zeitlichen Gründen gering zu halten oder fixiert ist. Es stellt sich die Frage, welche Werte in jedem Lauf den Variablen zuzuordnen sind. Herkömmliche Vorgehensweisen benutzen ausgefeilte, geschichtete Stichprobenverfahren, die jedoch Fehler bei der Bestimmung von Varianz und Kovarianz, aufgrund der Korrelation der Stichprobenpaare, beinhalten können. In dieser Arbeit wird eine Methode beschrieben, den absoluten Fehler zwischen dem tatsächlichen und dem korrelierenden Stichprobenpaar so klein wie möglich zu halten. Selbst für kleine Stichprobenumfänge können dabei schon optimale Pläne erzielt werden. Permutationsmatrizen haben die Eigenschaft, die Summe der Korrelationen zwischen Spaltenpaaren zu minimieren. Die vorgestellte Heuristik ist in der Lage, in allen getesteten Fällen das Optimum zu finden.
    Notes: Abstract The objective of Latin Hypercube Sampling is to determine an effective procedure for sampling from a (possibly correlated) multivariate population to estimate the distribution function (or at least a significant number of moments) of a complicated function of its variables. The typical application involves a computer-based model in which it is largely impossible to find a way (closed form or numerical) to do the necessary transformation of variables and where it is expensive to run in terms of computing resources and time. Classical approaches to hypercube sampling have used sophisticated stratified sampling techniques; but such sampling may provide incorrect measures of the output parameters' variances or covariances due to correlation between the sampling pairs. In this work, we offer a strategy which provides a sampling specification minimizing the sum of the absolute values of the pairwise differences between the true and sampled correlation pairs. We show that optimal plans can be obtained for even small sample sizes. We consider the characteristics of permutation matrices which minimize the sum of correlations between column pairs and then present an effective heuristic for solution. This heuristic generally finds plans which match the correlation structure exactly. When it does not, we provide a hybrid lagrangian/heuristic method, which empirically has found the optimal solution for all cases tested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01719258
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis of a self-scaling quasi-Newton method (1993)
    Springer
    Mathematical programming 61 (1993), S. 19-37 
    Details
    ISSN: 1436-4646
    Keywords: Self-scaling ; BFGS method ; quasi-Newton method ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We study the self-scaling BFGS method of Oren and Luenberger (1974) for solving unconstrained optimization problems. For general convex functions, we prove that the method is globally convergent with inexact line searches. We also show that the directions generated by the self-scaling BFGS method approach Newton's direction asymptotically. This would ensure superlinear convergence if, in addition, the search directions were well-scaled, but we show that this is not always the case. We find that the method has a major drawback: to achieve superlinear convergence it may be necessary to evaluate the function twice per iteration, even very near the solution. An example is constructed to show that the step-sizes required to achieve a superlinear rate converge to 2 and 0.5 alternately.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01582136
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  • 6
    Electronic Resource
    Electronic Resource
    Entropy principles in the prediction of water quality values at discontinued monitoring stations (1994)
    Springer
    Stochastic environmental research and risk assessment 8 (1994), S. 301-317 
    Details
    ISSN: 1436-3259
    Keywords: Change ; discontinued stations ; entropy ; networks ; optimization ; prediction ; unbiased ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A new methodology for predicting water quality values at discontinued water quality monitoring stations is proposed. The method is based upon the Principle of Maximum Entropy (POME) and provides unbiased predictions of water quality levels at upstream tributaries and on the mainstem of a river given observed changes in the distribution of the same water quality parameter at a downstream location. Changes in the values of water quality parameters which are known a priori to have occurred upstream, but which are not sufficiently large to account for all the observed change in the same water quality parameter at the downstream location are able to be incorporated in the method through the introduction of a new term in the basic entropy expression. Application of the procedure to water quality monitoring on the Mackenzie River in Queensland, Australia indicates the method has considerable potential for prediction of water quality at discontinued stations. The method also has potential for identifying the location of causes of observed changes in water quality at a downstream station.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01588759
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  • 7
    Electronic Resource
    Electronic Resource
    Cost-effective compliance with life safety codes (1996)
    Springer
    Fire technology 32 (1996), S. 291-296 
    Details
    ISSN: 1572-8099
    Keywords: Building codes ; building economics ; economic analysis ; fire safety ; health care facilities ; hospitals ; life safety codes ; linear programming ; mathematical programming ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract ALARM is personal computer software that helps building managers and fire safety engineers achieve cost-effective compliance with the widely used NFPA 101,Life Safety Code ®. The software currently supports health-care occupancy analysis. Through the equivalency provision of the code,ALARM implements a goal-oriented, or performance-based, approach to code compliance. The software generates a set of alternative code compliance strategies and their estimated construction costs. Engineering judgment is then applied to select the most appropriate code compliance strategy based on both cost and design considerations. The software offers a code-compliance optimizer, a comprehensive file manager, and a full-screen data editor. Since 1981, the optimization method used inALARM has been field-tested in 89 hospitals (17,898 beds). For this sample, the least-cost solution identified by the software was, on average, 41 percent less expensive than the prescriptive solution. This represents a potential cost savings of $2,116 per bed or more than $37 million. Future versions ofALARM could address other building occupancies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01037739
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  • 8
    Electronic Resource
    Electronic Resource
    Code Optimization Techniques in Embedded DSP Microprocessors (1998)
    Springer
    Design automation for embedded systems 3 (1998), S. 59-73 
    Details
    ISSN: 1572-8080
    Keywords: Code generation ; optimization ; digital signal processors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We address the problem of code optimization for embedded DSP microprocessors. Such processors (e.g., those in the TMS320 series) have highly irregular datapaths, and conventional code generation methods typically result in inefficient code. In this paper we formulate and solve some optimization problems that arise in code generation for processors with irregular datapaths. In addition to instruction scheduling and register allocation, we also formulate the accumulator spilling and mode selection problems that arise in DSP microprocessors. We present optimal and heuristic algorithms that determine an instruction schedule simultaneously optimizing accumulator spilling and mode selection. Experimental results are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008803430710
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  • 9
    Electronic Resource
    Electronic Resource
    Lazy techniques for fully expansive theorem proving (1993)
    Springer
    Formal methods in system design 3 (1993), S. 25-47 
    Details
    ISSN: 1572-8102
    Keywords: mechanical theorem proving ; primitive inference rules ; delayed computation ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The HOL system is afully expansive theorem prover: proofs generated in the system are composed of applications of the primitive inference rules of the underlying logic. One can have a high degree of confidence that such systems are sound, but they are far slower than theorem provers that exploit metatheoretic or derived properties. This paper presents techniques for postponing part of the computation so that the user of a fully expansive theorem prover can be more productive. The notions oflazy theorem andlazy conversion are introduced. These not only allow part of the computation to be delayed, but also permit nonlocal optimizations that are only possible because the primitive inferences are not performed immediately. The approach also opens the way to proof procedures that exploit metatheoretic properties without sacrificing security; the primitive inferences still have to be performed in order to generate a theorem, but during the proof development the user is free of the overheads they entail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01383983
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  • 10
    Electronic Resource
    Electronic Resource
    The achievable region method in the optimal control of queueing systems; formulations, bounds and policies (1995)
    Springer
    Queueing systems 21 (1995), S. 337-389 
    Details
    ISSN: 1572-9443
    Keywords: Queueing networks ; loss networks ; multiarmed bandits ; bounds ; policies ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We survey a new approach that the author and his co-workers have developed to formulate stochastic control problems (predominantly queueing systems) asmathematical programming problems. The central idea is to characterize the region of achievable performance in a stochastic control problem, i.e., find linear or nonlinear constraints on the performance vectors that all policies satisfy. We present linear and nonlinear relaxations of the performance space for the following problems: Indexable systems (multiclass single station queues and multiarmed bandit problems), restless bandit problems, polling systems, multiclass queueing and loss networks. These relaxations lead to bounds on the performance of an optimal policy. Using information from the relaxations we construct heuristic nearly optimal policies. The theme in the paper is the thesis that better formulations lead to deeper understanding and better solution methods. Overall the proposed approach for stochastic control problems parallels efforts of the mathematical programming community in the last twenty years to develop sharper formulations (polyhedral combinatorics and more recently nonlinear relaxations) and leads to new insights ranging from a complete characterization and new algorithms for indexable systems to tight lower bounds and nearly optimal algorithms for restless bandit problems, polling systems, multiclass queueing and loss networks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01149167
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  • 11
    Electronic Resource
    Electronic Resource
    Design of manufacturing systems using queueing models (1992)
    Springer
    Queueing systems 12 (1992), S. 135-213 
    Details
    ISSN: 1572-9443
    Keywords: Queueing networks ; manufacturing systems ; design ; optimization ; second order properties ; convexity ; supermodularity ; transposition increasingness ; Schur convexity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Design issues in various types of manufacturing systems such as flow lines, automatic transfer lines, job shops, flexible machining systems, flexible assembly systems and multiple cell systems are addressed in this paper. Approaches to resolving these design issues of these systems using queueing models are reviewed. In particular, we show how the structural properties that are recently derived for single and multiple stage queueing systems can be used effectively in the solution of certain design optimization problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01158638
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  • 12
    Electronic Resource
    Electronic Resource
    Optimal budgetary and monetary policies under uncertainty: A stochastic control approach (1995)
    Springer
    Annals of operations research 58 (1995), S. 379-402 
    Details
    ISSN: 1572-9338
    Keywords: Optimal control ; stochastic control ; dynamic systems ; economics ; public-sector applications ; optimization ; budgetary policies ; monetary policy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract In this paper, we determine optimal budgetary and monetary policies for Austria using a small macroeconometric model. We use a Keynesian model of the Austrian economy, called FINPOL1, estimated by ordinary least squares, which relates the main objective variables of Austrian economic policies, such as the growth rate of real gross domestic product, the rate of unemployment, the rate of inflation, the balance of payments, and the ratio of the federal budget deficit to GDP, to fiscal and monetary policy instruments, namely expenditures and revenues of the federal budget and money supply. Optimal fiscal and monetary policies are calculated for the model under a quadratic objective function using the algorithm OPTCON for the optimum control of nonlinear stochastic dynamic systems. Several control experiments are performed in order to assess the influence of different kinds of uncertainty on optimal budgetary and monetary policies. Apart from deterministic optimization runs, different assumptions about parameter uncertainties are introduced; the results of these different stochastic optimum control experiments are compared and interpreted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02038862
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  • 13
    Electronic Resource
    Electronic Resource
    Derivatives of probability functions and some applications (1995)
    Springer
    Annals of operations research 56 (1995), S. 287-311 
    Details
    ISSN: 1572-9338
    Keywords: Probability functions ; gradient of integral ; sensitivity analysis ; optimization ; discrete event dynamic systems ; shut-down problem ; probabilistic risk analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract Probability functions depending upon parameters are represented as integrals over sets given by inequalities. New derivative formulas for the intergrals over a volume are considered. Derivatives are presented as sums of integrals over a volume and over a surface. Two examples are discussed: probability functions with linear constraints (random right-hand sides), and a dynamical shut-down problem with sensors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02031712
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  • 14
    Electronic Resource
    Electronic Resource
    Radio Link Frequency Assignment (1999)
    Springer
    Constraints 4 (1999), S. 79-89 
    Details
    ISSN: 1572-9354
    Keywords: benchmarks ; radio link frequency assignment ; constraint satisfaction ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The problem of radio frequency assignment is to provide communication channels from limited spectral resources whilst keeping to a minimum the interference suffered by those whishing to communicate in a given radio communication network. This problem is a combinatorial (NP-hard) optimization problem. In 1993, the CELAR (the French “Centre d'Electronique de l'Armement”) built a suite of simplified versions of Radio Link Frequency Assignment Problems (RLFAP) starting from data on a real network Roisnel93. Initially designed for assessing the performances of several Constraint Logic Programming languages, these benchmarks have been made available to the public in the framework of the European EUCLID project CALMA (Combinatorial Algorithms for Military Applications). These problems should look very attractive to the CSP community: the problem is simple to represent, all constraints are binary and involve finite domain variables. They nevertheless have some of the flavors of real problems (including large size and several optimization criteria). This paper gives essential facts about the CELAR instances and also introduces the GRAPH instances which were generated during the CALMA project.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009812409930
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  • 15
    Electronic Resource
    Electronic Resource
    Semiring-Based CSPs and Valued CSPs: Frameworks, Properties, and Comparison (1999)
    Springer
    Constraints 4 (1999), S. 199-240 
    Details
    ISSN: 1572-9354
    Keywords: overconstrained problems ; constraint satisfaction ; optimization ; soft constraint ; dynamic programming ; branch and bound ; complexity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper we describe and compare two frameworks for constraint solving where classical CSPs, fuzzy CSPs, weighted CSPs, partial constraint satisfaction, and others can be easily cast. One is based on a semiring, and the other one on a totally ordered commutative monoid. While comparing the two approaches, we show how to pass from one to the other one, and we discuss when this is possible. The two frameworks have been independently introduced in ijcai95,jacm and schiex-ijcai95.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026441215081
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  • 16
    Electronic Resource
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    Optimal multithreshold control for a BMAP/G/1 queue with N service modes (1998)
    Springer
    Queueing systems 30 (1998), S. 273-287 
    Details
    ISSN: 1572-9443
    Keywords: single server queue ; controlled service rate ; batch Markovian arrival process ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper deals with the problem of the optimal service rate control in the system with BMAP (Batch Markovian Arrival Process) arrival stream. An algorithm for the computation of the embedded stationary queue length distribution is developed. The procedure for the cost criteria calculation is elaborated for any fixed parameters of the multithreshold control policy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019121222439
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  • 17
    Electronic Resource
    Electronic Resource
    The shuttle dispatch problem with compound Poisson arrivals: Controls at two terminals (1990)
    Springer
    Queueing systems 6 (1990), S. 207-221 
    Details
    ISSN: 1572-9443
    Keywords: Batch service queues ; bulk arrival queueing systems ; stochastic control ; optimization ; mass-transit systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We consider the control of an infinite capacity shuttle which transports passengers between two terminals. The passengers arrive at each terminal according to a compound Poisson process and the travel time from one terminal to the other is a random variable following an arbitrary distribution. The following control limit policy is considered: dispatch the shuttle at terminali, at the instant that the total number of passengers waiting at terminali reaches or exceeds a predetermined control limitm i . The objective of this paper is to obtain the mean waiting time of an arbitrary passenger at each terminal for given control valuesm 1 andm 2. We also discuss a search procedure to obtain the optimal control values which minimize the total expected cost per unit time under a linear cost structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411474
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  • 18
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    Planar heliocentric roto-translatory motion of a spacecraft with a solar sail of complex shape (1995)
    Springer
    Celestial mechanics and dynamical astronomy 63 (1995), S. 255-269 
    Details
    ISSN: 1572-9478
    Keywords: Solar sail ; orbit-rotation coupling ; passive radiative orientation ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A complete treatment of the general motion of rotation and translation of a solar-sail spacecraft is proposed for the non-flat sail of complex shape. The planar heliocentric roto-translatory motion is considered, orbit-rotational coupling in the problem of altitude and orbital sail motion is investigated for the two-folding sail formed by two unequal reflective rectangular plates oriented at a right angle. The problem of orbit-rotational coupling is essentially a planar one: both sail plates are orthogonal to the orbital plane. The possibility of the non-controlled interplanetary transfer with such two-folding sail at its passive radiational orientation is established analytically from point of view of orbit-rotational coupling. Optimal geometric proportions of this sail are found at minimum-time interplanetary transfers.
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    URL: http://dx.doi.org/10.1007/BF00692290
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  • 19
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    The effect of delayed feedback information on network performance (1992)
    Springer
    Annals of operations research 36 (1992), S. 101-124 
    Details
    ISSN: 1572-9338
    Keywords: Computer networks ; feedback control ; flow control ; optimization ; routing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract The performance of a network subject to either state dependent or state independent flow control is investigated. In the state dependent case, the flow control policy is a function of the total number of packets for which the controller has not yet received an acknowledgment. In this case it is shown that the optimal flow control is a sliding window mechanism. The effect of the delayed feedback on the network performance as well as the size of the window are studied. The state independent optimal rate is also derived. The performance of the state dependent and state independent flow control policies are compared. Conditions for employing one of the two types of flow control policies for superior end-to-end network performance are discussed. All the results obtained are demonstrated using simple examples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02094326
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  • 20
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    Scheduling a two-machine robotic cell: A solvable case (1995)
    Springer
    Annals of operations research 57 (1995), S. 217-232 
    Details
    ISSN: 1572-9338
    Keywords: Scheduling ; robotic cell ; tandem machines ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract The paper deals with the scheduling of a robotic cell in which jobs are processed on two tandem machines. The job transportation between the machines is done by a transportation robot. The robotic cell has limitations on the intermediate space between the machines for storing the work-in-process. What complicates the scheduling problem is that the loading/unloading operation times are non-negligible. Given the total number of operationsn, an optimalO(n logn)-time algorithm is proposed together with the proof of optimality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02099699
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  • 21
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    A review of open queueing network models of manufacturing systems (1992)
    Springer
    Queueing systems 12 (1992), S. 95-133 
    Details
    ISSN: 1572-9443
    Keywords: Open queueing networks ; job shops ; approximation procedures ; parametric decomposition approach ; optimization ; Brownian control ; system design ; review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper we review open queueing network models of manufacturing systems. The paper consists of two parts. In the first part we discuss design and planning problems arising in manufacturing. In doing so we focus on those problems that are best addressed by queueing network models. In the second part of the paper we describe developments in queueing network methodology. We are primarily concerned with features such as general service times, deterministic product routings, and machine failures — features that are prevalent in manufacturing settings. Since these features have eluded exact analysis, approximation procedures have been proposed. In the second part of this paper we review the developments in approximation procedures and highlight the assumptions that underlie these approaches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01158637
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    A queueing system with random server capacity and multiple control (1993)
    Springer
    Queueing systems 14 (1993), S. 369-384 
    Details
    ISSN: 1572-9443
    Keywords: Queue ; state dependent parameters ; semi-Markov process ; modulated process ; Markov process ; semi-regenerative process ; ergodic theorems ; steady state distribution ; invariant probability measure ; idle period ; busy period ; input process ; output process ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The authors study queueing, input and output processes in a queueing system with bulk service and state dependent service delay. The input flow of customers, modulated by a semi-Markov process, is served by a single server that takes batches of a certain fixed size if available or waits until the queue accumulates enough customers for service. In the latter case, the batch taken for service is of random size dependent on the state of the system, while service duration depends both on the state of the system and on the batch size taken. The authors establish a necessary and sufficient condition for equilibrium of the system and obtain the following results: Explicit formulas for steady state distribution of the queueing process, intensity of the input and output processes, and mean values of idle and busy periods. They employ theory of semi-regenerative processes and illustrate the results by a number of examples. In one of them an optimization problem is discussed.
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    URL: http://dx.doi.org/10.1007/BF01158874
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    Using integer programming techniques for the solution of an experimental design problem (1995)
    Springer
    Annals of operations research 58 (1995), S. 243-260 
    Details
    ISSN: 1572-9338
    Keywords: Assignment problem ; computer models ; distribution sampling ; estimation ; integer programming ; large-scale modelling ; latin hypercube ; optimization ; sampling ; sensitivity analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract Latin hypercube sampling is often used to estimate the distribution function of a complicated function of many random variables. In so doing, it is typically necessary to choose a permutation matrix which minimizes the correlation among the cells in the hypercube layout. This problem can be formulated as a generalized, multi-dimensional assignment problem. For the two-dimensional case, we provide a polynomial algorithm. For higher dimensions, we offer effective heuristic and bounding procedures.
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    URL: http://dx.doi.org/10.1007/BF02032134
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    Inference Duality as a Basis for Sensitivity Analysis (1999)
    Springer
    Constraints 4 (1999), S. 101-112 
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    ISSN: 1572-9354
    Keywords: sensitivity analysis ; duality ; optimization ; inference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The constraint programming community has recently begun to address certain types of optimization problems. These problems tend to be discrete or to have discrete elements. Although sensitivity analysis is well developed for continuous problems, progress in this area for discrete problems has been limited. This paper proposes a general approach to sensitivity analysis that applies to both continuous and discrete problems. In the continuous case, particularly in linear programming, sensitivity analysis can be obtained by solving a dual problem. One way to broaden this result is to generalize the classical idea of a dual to that of an “inference dual,” which can be defined for any optimization problem. To solve the inference dual is to obtain a proof of the optimal value of the problem. Sensitivity analysis can be interpreted as an analysis of the role of each constraint in this proof. This paper shows that traditional sensitivity analysis for linear programming is a special case of this approach. It also illustrates how the approach can work out in a discrete problem by applying it to 0-1 linear programming (linear pseudo-boolean optimization).
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    URL: http://dx.doi.org/10.1023/A:1009838725226
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    Scheduling policies using marked/phantom slot algorithms (1995)
    Springer
    Queueing systems 20 (1995), S. 207-254 
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    ISSN: 1572-9443
    Keywords: Scheduling ; random polling ; optimization ; perturbation analysis ; Golden Ratio policy ; radio network
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We address the problem of schedulingM customer classes in a single-server system, with customers arriving in one ofN arrival streams, as it arises in scheduling transmissions in packet radio networks. In general,N≠M and a customer from some stream may join one of several classes. We consider a slotted time model where at each scheduling epoch the server (channel) is assigned to a particular class (transmission set) and can serve multiple customers (packets) simultaneously, one from every arrival stream (network node) that can belong to this class. The assignment is based on arandom polling policy: the current time slot is allocated to theith class with probability θi. Our objective is to determine the optimal probabilities by adjusting them on line so as to optimize some overall performance measure. We present an approach based on perturbation analysis techniques, where all customer arrival processes can be arbitrary, and no information about them is required. The basis of this approach is the development of two sensitivity estimators leading to amarked slot and aphantom slot algorithm. The algorithms determine the effect of removing/ adding service slots to an existing schedule on the mean customer waiting times by directly observing the system. The optimal slot assignment probabilities are then used to design adeterministic scheduling policy based on the Golden Ratio policy. Finally, several numerical results based on a simple optimization algorithm are included.
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    URL: http://dx.doi.org/10.1007/BF01158437
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    A note on logspace optimization (1995)
    Springer
    Computational complexity 5 (1995), S. 155-166 
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    ISSN: 1420-8954
    Keywords: Complexity classes ; nondeterministic logspace ; optimization ; iterated multiplication ; 68Q15 ; 68Q25
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We show that computing iterated multiplication of word matrices over {0,1}*, using the operations maximum and concatenation, is complete for the class optL of logspace optimization functions. The same problem for word matrices over {1}* is complete for the class FNL of nondeterministic logspace functions. Improving previously obtained results, we furthermore place the class optL in AC1, and characterize FNL by restricted logspace optimization functions.
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    URL: http://dx.doi.org/10.1007/BF01268143
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    A general descent framework for the monotone variational inequality problem (1993)
    Springer
    Mathematical programming 61 (1993), S. 281-300 
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    ISSN: 1436-4646
    Keywords: Variational inequalities ; descent methods ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We present a framework for descent algorithms that solve the monotone variational inequality problem VIP v which consists in finding a solutionv *∈Ω v satisfyings(v *)T(v−v *)⩾0, for allv∈Ω v. This unified framework includes, as special cases, some well known iterative methods and equivalent optimization formulations. A descent method is developed for an equivalent general optimization formulation and a proof of its convergence is given. Based on this unified logarithmic framework, we show that a variant of the descent method where each subproblem is only solved approximately is globally convergent under certain conditions.
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    URL: http://dx.doi.org/10.1007/BF01582152
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    Some implementation issues associated with multidimensional interval Newton methods (1991)
    Springer
    Computing 47 (1991), S. 29-42 
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    ISSN: 1436-5057
    Keywords: 65K05 ; Interval Newton method ; interval arithmetic ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Die Arbeit entwickelt ein optimales Intervall-Newton-Verfahren für Systeme von nichtlinearen Gleichungen, wie sie im Zusammenhang mit nichtlinearen Optimierungsaufgaben auftreten. Die Modifikationen des Intervall-Newton-Verfahrens in dieser Arbeit stellen numerisch wirkungsvolle Verbesserungen des allgemeinen Intervall-Newton-Verfahrens dar. In der Arbeit wird aufgezeigt, daß die Berechnung einer optimalen Schrittweite im Intervall-Newton-Verfahren notwendig ist, damit man die Generierung einer feiner werdenden Einschließungsfolge garantieren kann. Dieses Vorgehen wird als optimales Newton-Verfahren bezeichnet und für den mehrdimensionalen Fall implementiert. Die Arbeit zeigt dann die Verwendung des optimalen Intervall-Newton-Verfahrens als “feasible direction”-Verfahren im Zusammenhang mit Nichtnegativitätsbedingungen. In der Implementierung wird auch eine Technik der Matrizenzerlegung verwendet, die den Rechenaufwand für die Inverse der Hesseschen Matrix im Intervall-Newton-Verfahren vermindert. Das Vorgehen wird an mehreren Beispielen demonstriert, u.a. an Optimierungsaufgaben mit Störungen der Problemkoeffizienten. Die numerischen Ergebnisse bestätigen die Leistungsfähigkeit unserer Ansätze.
    Notes: Abstract This paper presents the development of an optimal interval Newton method for systems of nonlinear equations. The context of solving such systems of equations is that of optimization of nonlinear mathematical programs. The modifications of the interval Newton method presented in this paper provide computationally effective enhancements to the general interval Newton method. The paper demonstrates the need to compute an optimal step length in the interval Newton method in order to guarantee the generation of a sequence of improving solutions. This method is referred to as the optimal Newton method and is implemented in multiple dimensions. Secondly, the paper demonstrates the use of the optimal interval Newton method as a feasible direction method to deal with non-negativity constraints. Also, included in this implementation is the use of a matrix decomposition technique to reduce the computational effort required to compute the Hessian inverse in the interval Newton method. The methods are demonstrated on several problems. Included in these problems are mathematical programs with perturbations in the problem coefficients. The numerical results clearly demonstrate the effectiveness and efficiency of these approaches.
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    Optimal synthesis of three-revolute manipulators (1994)
    Springer
    Meccanica 29 (1994), S. 95-103 
    Details
    ISSN: 1572-9648
    Keywords: Synthesis ; optimization ; kinematics ; robotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Sommario In questo lavoro si propone e viene discusso un metodo di ottimizzazione applicato alla sintesi di manipolatori, aventi una catena cinematica aperta con tre coppie rotoidali, la cui struttura soddisfi ai requisiti di ingombro minimo e spazio di lavoro assegnato tramite limitazioni prefissate. Per la risoluzione del problema à stata utilizzata una tecnica di programmazione quadratica sequenziale, la cui efficacia è dimostrata tramite esempi.
    Notes: Abstract An optimization method is proposed and discussed in order to synthesize a three-revolute open chain manipulator whose structure can have minimum size encumbrance and a workspace with prescribed constraints. The sequential quadratic programming optimization technique used has been successfully applied to the formulated problem as illustrated in some examples.
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    The multiple-robot assembly plan problem (1993)
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    Journal of intelligent and robotic systems 7 (1993), S. 57-71 
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    ISSN: 1573-0409
    Keywords: Assembly ; planning ; multi-robot systems ; optimization ; task allocation ; cooperation ; kitting ; heuristics ; cell design ; m-traveling salesmen problem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In previous research, we defined, classified, and solved the robotic assembly plan problem for a single assembly robot. In this paper, we formulate this problem for the case of multiple, cooperating assembly robots. The problem now includes the allocation of assembly tasks among multiple robots.
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    URL: http://dx.doi.org/10.1007/BF01258212
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    Vector performance estimation for CRAY X-MP/Y-MP supercomputers (1992)
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    The journal of supercomputing 6 (1992), S. 49-70 
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    ISSN: 1573-0484
    Keywords: CRAY X-MP/Y-MP ; memory conflicts ; optimization ; performance estimation ; vectorization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Optimization of vector-intensive applications for the CRAY X-MP/Y-MP often requires arranging the operations to take full advantage of such architectural features as the memory system, independent memory ports, chaining, and independent functional units. Estimation of performance is not straightforward since many operations can occur concurrently. As a tool for making trades between vector algorithms, a method has been developed and used successfully at E-Systems Inc. to predict the execution time of a sequence of vector operations without resorting to actual code development. This method reduced our software development time, produced significantly more efficient code, and provided for a systematic approach to optimization. The performance estimation is generally accurate to within 10% and accounts for memory conflicts that result from fixed stride references.
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    Loop headers in λ-calculus or CPS (1994)
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    Higher-order and symbolic computation 7 (1994), S. 337-343 
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    ISSN: 1573-0557
    Keywords: compiler ; optimization ; loop header ; continuation-passing style ; lambda-calculus ; in-line expansion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The introduction of a “loop header” block facilitates the hoisting of loop-invariant code from a loop. In a λ-calculus intermediate representation, which has a notion of scope, this transformation is particularly useful. Loop headers with scope also solve a problem with in-line expansion of recursive functions or loops: if done naively, only the first iteration is inlined. A loop header can encapsulate the loop or recursion for better in-line expansion. This optimization improves performance by about 5% in Standard ML of New Jersey.
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    C for numerical computing (1991)
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    The journal of supercomputing 5 (1991), S. 31-48 
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    ISSN: 1573-0484
    Keywords: C language ; numerical computing ; Fortran ; data type ; floating point arithmetic ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The predominant programming language for numerical and scientific applications is Fortran, and super-computers are primarily used to run large-scale numerical and scientific applications. C is not widely used for numerical and scientific programming, yet C provides many desirable linguistic features not present in Fortran-77. Furthermore, the existence of a standard library and preprocessor eliminates the worst portability problems. A comparison of C and Fortran-77 shows several key deficiencies in C that reduce its desirability for some numerical problems. Some of these problems have already been addressed by the new ANSI standard for C, but others remain. C with a few extensions and modifications could be suitable for all numerical applications and could become more popular in supercomputing environments.
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    A massively parallel genetic algorithm for RNA secondary structure prediction (1994)
    Springer
    The journal of supercomputing 8 (1994), S. 195-207 
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    ISSN: 1573-0484
    Keywords: Genetic algorithms ; RNA structure prediction ; massively parallel ; dynamic programming ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We present a new method for predicting RNA secondary structure based on a genetic algorithm. The algorithm is designed to run on a massively parallel SIMD computer. Statistical analysis shows that the program performs well when compared to a dynamic programming algorithm used to solve the same problem. The program has also pointed out a long-standing simplification in the implementation of the original dynamic programming algorithm that sometimes causes it not to find the optimal secondary structure.
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    Does It Matter How Price Promotions Are Operationalized? (1997)
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    Marketing letters 8 (1997), S. 167-181 
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    ISSN: 1573-059X
    Keywords: price and promotion ; economics models ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract Does it matter if managers use an absolute amount or the relativepercentage discount when determining the optimal price and promotionalstrategy for a good? Intuitively, one might expect that the results ofboth models (deal amount and deal percentage) would be identical. Thisresearch shows that the deal-percentage model dominates the deal-amountmodel on three dimensions: (1) consumers pay more when an amount modelis used, (2) the seller has lower profits and different promotionalstrategies when an amount model is used, and (3) consumer behavior isunrealistically constrained by the amount model. This research showsthat whenever the seller offers a promotion in the deal-amount model,the net price paid by the consumer (regular price minus the deal) isalways higher than the net price in the deal-discount model. Thisresult implies that the ultimate price and promotional strategy (suchas depth of promotion, timing of promotions, and so on) prescribed bythe models are different. Additionally, this research shows that whenconsumers respond similarly in the models, the seller's profits arehigher in the deal-percentage model. This finding is a direct result ofthe higher net price in the deal-amount model. Finally, contrary toempirical findings in the marketing literature, the deal-amount modelrequires consumers to respond more strongly to price changes than topromotions (that is, the promotional elasticity plus one must be lessthan the magnitude of the price elasticity) for the optimal price to bepositive. The deal-percentage model does not place similar restrictionson consumer behavior.
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    Evolution by damage spreading in Kauffman model (1994)
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    Journal of statistical physics 74 (1994), S. 1293-1299 
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    ISSN: 1572-9613
    Keywords: Cellular automata ; critical phenomena ; optimization ; spin glass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In Kauffman's Boolean automata model on the square lattice, the Darwinian fitness of survival can be defined as the fraction of elements which do not change from one iteration to the next. Biological mutations are simulated by filpping one bit in the rule of one site. Selection of the fitter mutant then optimizes the whole lattice completely. This optimization is particularly effective near the critical point of the transition to chaos, but is in itself not a critical phenomenon. Also a two-dimensional spin glass can be optimized in this way.
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    Comparison of Extended Jacobian and Lagrange Multiplier Based Methods for Resolving Kinematic Redundancy (1997)
    Springer
    Journal of intelligent and robotic systems 19 (1997), S. 39-54 
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    ISSN: 1573-0409
    Keywords: extended Jacobian method ; Lagrange multiplier method ; kinematically redundant manipulators ; numerical efficiency ; optimization ; robotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Several methods have been proposed in the past for resolving the control of kinematically redundant manipulators by optimizing a secondary criterion. The extended Jacobian method constrains the gradient of this criterion to be in the null space of the Jacobian matrix, while the Lagrange multiplier method represents the gradient as being in the row space. In this paper, a numerically efficient form of the Lagrange multiplier method is presented and is compared analytically, computationally, and operationally to the extended Jacobian method. This paper also presents an improved method for tracking algorithmic singularities over previous work.
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    URL: http://dx.doi.org/10.1023/A:1007941331202
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    Probability-Based Weighting of Performance Criteria for Redundant Manipulators (1997)
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    Journal of intelligent and robotic systems 19 (1997), S. 89-103 
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    ISSN: 1573-0409
    Keywords: kinematics ; manipulator ; optimization ; performance criteria ; redundancy ; robot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A method to simultaneously optimize multiple performance criteria for a redundant manipulator is presented. Preferred formulation requirements for the criteria are discussed, and previously proposed normalization methods are examined. A statistically based variable weighting technique is developed and evaluated. A seven-degree-of-freedom Robotics Research Corporation manipulator is used as a test bed for the multiple criteria optimization scheme.
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    URL: http://dx.doi.org/10.1023/A:1007949601160
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    Learning Complex Tasks Using a Stepwise Approach (1999)
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    Journal of intelligent and robotic systems 24 (1999), S. 43-68 
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    ISSN: 1573-0409
    Keywords: learning robots ; system organization ; optimization ; physical equation ; look-ut table ; neural networks ; fuzzy controllers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper explores a stepwise learning approach based on a system's decomposition into functional subsystems. Two case studies are examined: a visually guided robot that learns to track a maneuvering object, and a robot that learns to use the information from a force sensor in order to put a peg into a hole. These two applications show the features and advantages of the proposed approach: i) the subsystems naturally arise as functional components of the hardware and software; ii) these subsystems are building blocks of the robot behavior and can be combined in several ways for performing various tasks; iii) this decomposition makes it easier to check the performances and detect the cause of a malfunction; iv) only those subsystems for which a satisfactory solution is not available need to be learned; v) the strategy proposed for coordinating the optimization of all subsystems ensures an improvement at the task-level; vi) the overall system's behavior is significantly improved by the stepwise learning approach.
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    Globally Optimal Trajectory Planning for Redundant Manipulators using State Space Augmentation Method (1997)
    Springer
    Journal of intelligent and robotic systems 19 (1997), S. 105-117 
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    ISSN: 1573-0409
    Keywords: optimization ; Pontryagin’s maximum principle ; redundant manipulators ; state-space augmentation ; trajectory planning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The off-line global trajectory planning for kinematically redundant manipulators is formulated as an optimization problem whose solution is obtained by applying the Pontryagin’s Maximum Principle. The state space augmentation method is developed to obtain a set of optimal joint trajectories corresponding to a singularity-free Cartesian path which avoids joint limits and conserves joint configuration in cyclic motion. Results of computer simulation conducted on a three-degree-of-freedom planar manipulator are presented and discussed.
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    Coordination and Control of Multi-fingered Robot Hands with Rolling and Sliding Contacts (1999)
    Springer
    Journal of intelligent and robotic systems 24 (1999), S. 125-149 
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    ISSN: 1573-0409
    Keywords: planning ; control ; multi-fingered robot hand ; optimization ; internal force ; simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper, the problem of controlling multi-fingered robot hands with rolling and sliding contacts is addressed. Several issues are explored. These issues involve the kinematic analysis and modeling, the dynamic analysis and control, and the coordination of a multi-fingered robot hand system. Based on a hand-object system in which the contacts are allowed to both roll and slide, a kinematic model is derived and analyzed. Also, the dynamic model of the hand-object system with relative motion contacts is studied. A control law is proposed to guarantee the asymptotic tracking of the object trajectory together with the desired rolling and/or sliding motions along the surface of the object. A planning approach is then introduced to minimize the contact forces so that the desired motion of the object and the relative motions between the fingers and the object can be achieved. Simulation results which support the theoretical development are presented.
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    Empirical learning using rule threshold optimization for detection of events in synthetic images (1990)
    Springer
    Machine learning 5 (1990), S. 427-450 
    Details
    ISSN: 0885-6125
    Keywords: Learning ; image interpretation ; detection ; optimization ; genetic algorithms ; thresholded rules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We have developed an expert system for interpretation of passive sonar images. A key component of the system is a group of event detection rules whose conditions consist of tests against thresholds. Due to the complexity, variability and clumpiness (i.e., tendency towards highly nonuniform distribution) of the data, tuning these thresholds for good performance under all conditions is a difficult task. We have implemented a procedure for learning rule thresholds whereby the detection capability of each rule continually improves as more and more data is played through the system. The learning procedure contains the following components: 1) a windowing mechanism that adds exceptions (i.e., false alarms and missed detections) into a training database of positive and negative examples and 2) a genetic algorithm to optimize the thresholds with respect to the training database. The genetic training algorithm allows the developer to explicitly choose an operating point on the Receiver Operating Characteristic (ROC) curve of a rule. Experiments have verified 1) the superiority of this automated approach to selecting rule thresholds over manual techniques and 2) the improvement of rule performance with experience.
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    Empirical Learning Using Rule Threshold Optimization for Detection of Events in Synthetic Images (1990)
    Springer
    Machine learning 5 (1990), S. 427-450 
    Details
    ISSN: 0885-6125
    Keywords: Learning ; image interpretation ; detection ; optimization ; genetic algorithms ; thresholded rules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We have developed an expert system for interpretation of passive sonar images. A key component of the system is a group of event detection rules whose conditions consist of tests against thresholds. Due to the complexity, variability and clumpiness (i.e., tendency towards highly nonuniform distribution) of the data, tuning these thresholds for good performance under all conditions is a difficult task. We have implemented a procedure for learning rule thresholds whereby the detection capability of each rule continually improves as more and more data is played through the system. The learning procedure contains the following components: 1) a windowing mechanism that adds exceptions (i.e., false alarms and missed detections) into a training database of positive and negative examples and 2) a genetic algorithm to optimize the thresholds with respect to the training database. The genetic training algorithm allows the developer to explicitly choose an operating point on the Receiver Operating Characteristic (ROC) curve of a rule. Experiments have verified 1) the superiority of this automated approach to selecting rule thresholds over manual techniques and 2) the improvement of rule performance with experience.
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    Statistical physics of fault patterns self-organized by repeated earthquakes (1994)
    Springer
    Pure and applied geophysics 142 (1994), S. 491-527 
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    ISSN: 1420-9136
    Keywords: Self-organization ; self-organized criticality ; random directed polymer ; fractals ; multi-fractals ; faults ; earthquakes ; competition ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract This work presents at attempt to model brittle ruptures and slips in a continental plate and its spontaneous organization by repeated earthquakes in terms of coarse-grained properties of the mechanical plate. A statistical physics model, which simulates anti-plane shear deformation of a thin plate with inhomogeneous elastic properties, is thus analyzed theoretically and numerically in order to study the spatio-temporal evolution of rupture patterns in response to a constant applied strain rate at its borders, mimicking the effect of neighboring plates. Rupture occurs when the local stress reaches a threshold value. Broken elements are instantaneously healed and retain the original material properties, enabling the occurrence of recurrent earthquakes. Extending previous works (Cowie et al., 1993;Miltenberger et al., 1993), we present a study of the most startling feature of this model which is that ruptures become strongly correlated in space and time leading to the spontaneous development of multifractal structures and gradually accumulate large displacements. The formation of the structures and the temporal variation of rupture activity is due to a complex interplay between the random structure, long-range elastic interactions and the threshold nature of rupture physics. The spontaneous formation of fractal fault structures by repeated earthquakes is mirrored at short times by the spatio-temporal chaotic dynamics of earthquakes, well-described by a Gutenberg-Richter power law. We also show that the fault structures can be understood as pure geometrical objects, namely minimal manifolds, which in two dimensions correspond to the random directed polymer (RDP) problem. This mapping allows us to use the results of many studies on the RDP in the field of statistical physics, where it is an exact result that the minimal random manifolds in 2D systems are self-affine with a roughness exponent 2/3. We also present results pertaining to the influence of the degree β of stress release per earthquake on the competition between faults. Our results provide a rigorous framework from which to initiate rationalization of many, reported fractal fault studies.
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    Lens Design: Global Optimization with Escape Function (1995)
    Springer
    Optical review 2 (1995), S. 463-470 
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    ISSN: 1349-9432
    Keywords: lens design ; optimization ; global optimization ; damped least squares method ; damping factor ; aberration ; merit function ; escape function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The technique of using the ‘escape function’ for global optimization in lens design is described. This includes how to identify two solutions as independent; the threshold value for this criterion can be chosen to determine how to explore local solutions—rough or fine. Choice of appropriate values for two parameters in the escape function is most important, since this will affect the efficiency of the automatic global optimization process. There are two problems, i.e. giving default values at the beginning of the design, and determining a default rule to change them when the escape is unsuccessful. The latter was solved by assuming a ‘saddle path’ as the best route to escape. An exact solution for the former was not found, but a hint for finding a second best solution is shown based on the statistical study of local minima.
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    URL: http://dx.doi.org/10.1007/s10043-995-0463-6
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    Lens Design: An Attempt to Use ‘Escape Function’ as a Tool in Global Optimization (1995)
    Springer
    Optical review 2 (1995), S. 47-51 
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    ISSN: 1349-9432
    Keywords: lens design ; optimization ; global optimization ; damped least squares method ; damping factor ; aberration ; merit function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In designing lenses with the damped least squares method, the solution obtained by optimization routine is a local minimum of the merit function. To get out of this and seek a different solution, we propose to use an ‘escape function’ as an additional operand of the lens system, to be controlled. Experiments were made on simple models of merit function and the advantage of this technique was ascertained. We also planted this algorithm into OSLO SIX (lens design software by Sinclair Optics) by means of CCL (C-compatible language) and applied it to actual lens design. Experiments convinced us that the method would be an effective tool for global optimization.
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    URL: http://dx.doi.org/10.1007/s10043-995-0047-5
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    Multiobjective fuzzy optimum design of antenna structures (1990)
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    Acta mechanica solida Sinica 3 (1990), S. 81-91 
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    ISSN: 0894-9166
    Keywords: fuzzy ; optimization ; application ; multiobjective ; antenna ; structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract On the basis of the recently proposed general fuzzy optimization [1–2], this paper investigates the multiobjective fuzzy optimum design of antenna structures, in which the weight objective, precision objective, lowest frequency objective and safety degree objective are included. This is a successful application of fuzzy optimization to large engineering structures.
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    URL: http://dx.doi.org/10.1007/BF02205626
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    An efficient genetic algorithm for large scale built-up structural optimization (1994)
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    Acta mechanica solida Sinica 7 (1994), S. 29-38 
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    ISSN: 0894-9166
    Keywords: optimization ; zigzag method ; GAs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract In this paper, a new zigzag method for plate structures and a genetic algorithm (GA) of dynamic source seed spaces are developed and a combination of them is used to deal with large scale built-up structural optimization. The new GA combined with the zigzag method can work efficiently when coping with large scale structural optimization included displacement and stress constraints. Examples show that this GA is robust and can be used for many complex structural optimization problems.
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    An optimization framework for feature extraction (1991)
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    Machine vision and applications 4 (1991), S. 59-87 
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    ISSN: 1432-1769
    Keywords: optimization ; feature extraction ; minimal encoding ; generic models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper, we propose a unified optimization framework for feature extraction that lets us simultaneously take into account image data and semantic knowledge: We model objects using a language that specifies both photometric and geometric constraints and defines an information-theoretic objective function that measures the fit of the models to the data. We then treat the problem of finding objects as one of generating the optimal description of the image in terms of this language. We have validated our framework by performing extensive experiments on detecting objects in aerial imagery described by simple geometric constraints and have developed two algorithms for generating optimal descriptions. The first one starts with a rough sketch of a polygonal object and deforms the initial contour to maximize the objective function, thus finding object outlines. The second one automatically extracts complex rectilinear buildings from complex aerial images.
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    Adaptive mutation in genetic algorithms (2000)
    Springer
    Soft computing 4 (2000), S. 76-80 
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    ISSN: 1433-7479
    Keywords: Key words Genetic algorithms ; optimization ; numerical methods ; search methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract  In Genetic Algorithms mutation probability is usually assigned a constant value, therefore all chromosome have the same likelihood of mutation irrespective of their fitness. It is shown in this paper that making mutation a function of fitness produces a more efficient search. This function is such that the least significant bits are more likely to be mutated in high-fitness chromosomes, thus improving their accuracy, whereas low-fitness chromosomes have an increased probability of mutation, enhancing their role in the search. In this way, the chance of disrupting a high-fitness chromosome is decreased and the exploratory role of low-fitness chromosomes is best exploited. The implications of this new mutation scheme are assessed with the aid of numerical examples.
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    Computing a closest bifurcation instability in multidimensional parameter space (1993)
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    Journal of nonlinear science 3 (1993), S. 307-327 
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    ISSN: 1432-1467
    Keywords: bifurcation ; saddle node ; Hopf ; stability ; robustness ; optimization ; numerical methods ; transcritical ; pitchfork ; extended systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Summary Engineering and physical systems are often modeled as nonlinear differential equations with a vector λ of parameters and operated at a stable equilibrium. However, as the parameters λ vary from some nominal value λ0, the stability of the equilibrium can be lost in a saddle-node or Hopf bifurcation. The spatial relation in parameter space of λ0 to the critical set of parameters at which the stable equilibrium bifurcates determines the robustness of the system stability to parameter variations and is important in applications. We propose computing a parameter vector λ* at which the stable equilibrium bifurcates which is locally closest in parameter space to the nominal parameters λ0. Iterative and direct methods for computing these locally closest bifurcations are described. The methods are extensions of standard, one-parameter methods of computing bifurcations and are based on formulas for the normal vector to hypersurfaces of the bifurcation set. Conditions on the hypersurface curvature are given to ensure the local convergence of the iterative method and the regularity of solutions of the direct method. Formulas are derived for the curvature of the saddle node bifurcation set. The methods are extended to transcritical and pitchfork bifurcations and parametrized maps, and the sensitivity to λ0 of the distance to a closest bifurcation is derived. The application of the methods is illustrated by computing the proximity to the closest voltage collapse instability of a simple electric power system.
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    Optimizing environmental product life cycles (1997)
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    Environmental and resource economics 9 (1997), S. 199-224 
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    ISSN: 1573-1502
    Keywords: environmental policy ; pulp and paper ; life cycle ; optimization ; technology lock-in ; recycling ; geography of production ; environment-trade conflict
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract In this paper, we propose a methodology, based on materials accounting and operational research techniques, to assess different industry configurations according to their life cycle environmental impacts. Rather than evaluating a specific technology, our methodology searches for the feasible configuration with the minimum impact. This approach allows us to address some basic policy-relevant questions regarding technology choice, investment priorities, industrial structures, and international trade patterns. We demonstrate the methodology in the context of the European pulp and paper industry. We are able to show that current environmental policy's focus on maximizing recycling is optimal now, but that modest improvements in primary pulping technology may shift the optimal industry configuration away from recycling toward more primary pulping with incineration. We show that this will have significant implications for the amount and type of environmental damage, for the location of different stages in the production chain, and for trade between European member states. We caution policy makers that their single-minded focus on recycling may foreclose investment in technologies that could prove environmentally superior. Finally, we hint that member state governments may be fashioning their environmental policy positions at least in part on some of the trade and industrial implications we find.
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    A Computationally Convenient Diversity Measure: Theory and Application (1997)
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    Environmental and resource economics 9 (1997), S. 409-427 
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    ISSN: 1573-1502
    Keywords: structural diversity ; optimization ; resource management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract This paper introduces a computationally convenient measure of structural diversity based on absolute deviations between relative shares of individual groups forming a community. A conceptual framework is developed, some theoretical properties of the measure are derived, and its close relation to the Shannon index, a widely used diversity measure, is explored. The paper also presents an empirical application involving this measure where optimum harvesting strategies are determined under diversity constraints, and investigates the trade off between economic and environmental objectives for a mixed forest in Indonesia.
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    URL: http://dx.doi.org/10.1023/A:1026471929166
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    The optimal truncated low-dimensional dynamical systems based on flow databases (1996)
    Springer
    Acta mechanica Sinica 12 (1996), S. 104-116 
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    ISSN: 1614-3116
    Keywords: partial differential equation ; flow database ; optimization ; dynamical system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A new theory on the construction of optimal truncated Low-Dimensional Dynamical Systems (LDDSs) with different physical meanings has been developed. The physical properties of the optimal bases are reflected in the user-defined optimal conditions. Through the analysis of linear and nonlinear examples, it is shown that the LDDSs constructed by using the Proper Orthogonal Decomposition (POD) method are not the optimum. After comparing the errors of LDDSs based on the new theory, POD and Fourier methods, it is concluded that the LDDSs based on the new theory are optimally truncated and catch the desired physical properties of the systems.
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    Solving Irregular Econometric and Mathematical Optimization Problems with a Genetic Hybrid Algorithm (1999)
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    Computational economics 13 (1999), S. 103-115 
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    ISSN: 1572-9974
    Keywords: optimization ; econometric functions ; nonlinear programming ; evolutionary programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Economics
    Notes: Abstract In the present paper we apply a new Genetic Hybrid Algorithm (GHA) to globally minimize a representative set of ill-conditioned econometric/mathematical functions. The genetic algorithm was specifically designed for nonconvex mixed integer nonlinear programming problems and it can be successfully applied to both global and constrained optimization. In previous studies, we have demonstrated the efficiency of the GHA in solving complicated NLP, INLP and MINLP problems. The present study is a continuation of this research, now focusing on a set of highly irregular optimization problems. In this paper we discuss the genetic hybrid algorithm, the nonlinear problems to be solved and present the results of the empirical tests.
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    The Bioeconomics of Marine Sanctuaries (1999)
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    Journal of bioeconomics 1 (1999), S. 205-217 
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    ISSN: 1573-6989
    Keywords: economics ; fisheries ; optimization ; stochastic simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Economics
    Notes: Abstract Consider an offshore fishing grounds of size K. Suppose the grounds has been overfished to the point that net revenue has been driven to zero and the fishery is in open access equilibrium at (X∞, Y∞). A marine sanctuary, where fishing is prohibited, is then created. Suppose the marine sanctuary is of size K2 and that fishing is allowed on a smaller grounds, now of size K1, where K1 + K2 = K. In the first, deterministic, model, the present value of net revenue from the grounds-sanctuary system is maximized subject to migration (diffusion) of fish from the sanctuary to the grounds. The size of the sanctuary is varied, the system is re-optimized, and the populations levels, harvest, and value of the fishery is compared to the 'no-sanctuary' optimum, and the open access equilibrium. In the deterministic model, a marine sanctuary reduces the present value of the fishery relative to the 'ideal' of optimal management of the original grounds. In the second model net growth is subject to stochastic fluctuation. Simulation demonstrates the ability of a marine sanctuary to reduce the variation in biomass on the fishing grounds. Variance reduction in fishable biomass is examined for different-sized sanctuaries when net growth on the grounds and in the sanctuary fluctuate independently and when they are perfectly correlated. For the stochastic model of this paper, sanctuaries ranging in size from 60 to 40% of the original grounds (0.6 ≥ K2/K ≥ 0.4) had the ability to lower variation in fishable biomass compared to the no sanctuary case. For a sanctuary equal to or greater than 70% of the original grounds (K2 ≥ 0.7K), net revenue would be nonpositive and there would be no incentive to fish.
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    Survival of the Most Foolish of Fools: The Limits of Evolutionary Selection Theory (2000)
    Springer
    Journal of bioeconomics 2 (2000), S. 203-220 
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    ISSN: 1573-6989
    Keywords: productivity ; efficiency ; hysteresis ; path dependency ; rationality ; market selection ; natural selection ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Economics
    Notes: Abstract The paper investigates whether evolutionary selection, in nature or the market, ensures the survival of rational agents. It argues that once rationality appears, evolutionary selection can account for its diffusion—but cannot account for its appearance in the first place. This issue differs from the investigation of whether history matters. The issue of history or path-dependency focuses on whether evolutionary selection can favor the survival of the potentially most productive apparatus (in the biological or technological sense). To show this, the paper commences with the much-neglected difference between efficiency and productivity.
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    Approximation of the capillarity problem by an augmented lagrangian method (1996)
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    Numerical algorithms 12 (1996), S. 321-346 
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    ISSN: 1572-9265
    Keywords: Capillarity ; numerical approximation ; optimization ; 65Dxx ; 65Gxx ; 65K10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We propose an algorithm to compute an approximation of capillary surfaces in a gravitational field. This algorithm is based on a decomposition-coordination method by augmented lagrangians and the discretization is done using the finite element method. We study the convergence of the algorithm and the error of discretization for the axisymmetric case; some numerical results are given. This method can be generalized to a two-dimensional space.
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    A new approach to inverse problems of wave equations (1990)
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    Applied mathematics and mechanics 11 (1990), S. 1113-1117 
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    ISSN: 1573-2754
    Keywords: inverse problem ; wave equation ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract We introduce a multi-cost-functional method for solving inverse problems of wave equations. This method has its simplicity, efficiency and good physical interpretation. It has the advantage of being programmed for two- or three- (space) dimensional problems as well as for one-dimensional problems.
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    Modified quadratic hill-climbing with SAS/IML (1991)
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    Computational economics 4 (1991), S. 15-31 
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    ISSN: 1572-9974
    Keywords: Hill-climbing ; maximum likelihood estimation ; non-linear least squares ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Economics
    Notes: Abstract This article describes EZClimb, a set of SAS/IML steps useful in solving numerical optimization problems. The program uses the method of modified quadratic hill-climbing with either analytical or numerical derivatives to maximize a user-defined criterion function. Modified quadratic hill-climbing is one of the more powerful algorithms known for function optimization but is not widely available outside of the software package GQOPT. The efficacy of the SAS steps is illustrated using Rosenbrock's function, Savin and White's Box-Cox extended autoregressive model, and Klein's Model I.
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    Preliminary Optimal Geometric Modeling of Mechanical Components: A Multiobjective Approach (2000)
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    Journal of systems integration 10 (2000), S. 23-39 
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    ISSN: 1573-8787
    Keywords: computer-integrated design ; mechanical design ; engineering methodology ; CAD ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper a methodologyto improve the development of mechanical components during thefirst design phase is proposed. This phase is one of the mostimportant ones in order to build up a product meeting with consumers'approval. The approach is based on a preliminary geometric-structuralmodeling optimization of the component studied. This optimizationis of a multiobjective kind and it aims to obtain some meaningfulgoals to find feasible shapes of the component to design. Themaximization/minimization of the objective functions is performedby an evolutionary algorithm to accomplish a constrained optimizationusing discrete variables. The characteristics of the methodologyare pointed out in relation to the properties of the evolutionaryalgorithm implemented. The paper concludes with an applicationexample of the procedure. The case study is a car gearbox. Threeobjectives are simultaneously pursued: the lowest weight, thegreatest flexural and torsional stiffnesses.
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    The FFT Moving Average (FFT-MA) Generator: An Efficient Numerical Method for Generating and Conditioning Gaussian Simulations (2000)
    Springer
    Mathematical geology 32 (2000), S. 701-723 
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    ISSN: 1573-8868
    Keywords: simulation ; nonlinear conditioning ; optimization ; FFT ; local perturbation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract A fast Fourier transform (FFT) moving average (FFT-MA) method for generating Gaussian stochastic processes is derived. Using discrete Fourier transforms makes the calculations easy and fast so that large random fields can be produced. On the other hand, the basic moving average frame allows us to uncouple the random numbers from the structural parameters (mean, variance, correlation length, ... ), but also to draw the randomness components in spatial domain. Such features impart great flexibility to the FFT-MA generator. For instance, changing only the random numbers gives distinct realizations all having the same covariance function. Similarly, several realizations can be built from the same random number set, but from different structural parameters. Integrating the FFT-MA generator into an optimization procedure provides a tool theoretically capable to determine the random numbers identifying the Gaussian field as well as the structural parameters from dynamic data. Moreover, all or only some of the random numbers can be perturbed so that realizations produced using the FFT-MA generator can be locally updated through an optimization process.
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    Mathematical Analysis and Optimization of Infiltration Processes (1998)
    Springer
    Journal of scientific computing 13 (1998), S. 303-321 
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    ISSN: 1573-7691
    Keywords: Infiltration processes ; optimization ; partial differential equations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A variety of infiltration techniques can be used to fabricate solid materials, particularly composites. In general these processes can be described with at least one time dependent partial differential equation describing the evolution of the solid phase, coupled to one or more partial differential equations describing mass transport through a porous structure. This paper presents a detailed mathematical analysis of a relatively simple set of equations which is used to describe chemical vapor infiltration. The results demonstrate that the process is controlled by only two parameters, α and β. The optimization problem associated with minimizing the infiltration time is also considered. Allowing α and β to vary with time leads to significant reductions in the infiltration time, compared with the conventional case where α and β are treated as constants.
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    Evolving Multilayer Perceptrons (2000)
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    Neural processing letters 12 (2000), S. 115-128 
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    ISSN: 1573-773X
    Keywords: evolutionary algorithms ; generalization ; learning ; neural networks ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper proposes a new version of a method (G-Prop, genetic backpropagation) that attempts to solve the problem of finding appropriate initial weights and learning parameters for a single hidden layer Multilayer Perceptron (MLP) by combining an evolutionary algorithm (EA) and backpropagation (BP). The EA selects the MLP initial weights, the learning rate and changes the number of neurons in the hidden layer through the application of specific genetic operators, one of which is BP training. The EA works on the initial weights and structure of the MLP, which is then trained using QuickProp; thus G-Prop combines the advantages of the global search performed by the EA over the MLP parameter space and the local search of the BP algorithm. The application of the G-Prop algorithm to several real-world and benchmark problems shows that MLPs evolved using G-Prop are smaller and achieve a higher level of generalization than other perceptron training algorithms, such as QuickPropagation or RPROP, and other evolutive algorithms. It also shows some improvement over previous versions of the algorithm.
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    Neural network for optimal steiner tree computation (1996)
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    Neural processing letters 3 (1996), S. 139-149 
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    ISSN: 1573-773X
    Keywords: Steiner tree ; neural networks ; Hopfield model ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Hopfield neural network model for finding the shortest path between two nodes in a graph was proposed recently in some literatures. In this paper, we present a modified version of Hopfield model to a more general problem of searching an optimal tree (least total cost tree) from a source node to a number of destination nodes in a graph. This problem is called Steiner tree in graph theory, where it is proved to be a NP-complete. Through computer simulations, it is shown that the proposed model could always find an optimal or near-optimal valid solution in various graphs.
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    The Racing Algorithm: Model Selection for Lazy Learners (1997)
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    Artificial intelligence review 11 (1997), S. 193-225 
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    ISSN: 1573-7462
    Keywords: lazy learning ; model selection ; cross validation ; optimization ; attribute selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Given a set of models and some training data, we would like to find the model that best describes the data. Finding the model with the lowest generalization error is a computationally expensive process, especially if the number of testing points is high or if the number of models is large. Optimization techniques such as hill climbing or genetic algorithms are helpful but can end up with a model that is arbitrarily worse than the best one or cannot be used because there is no distance metric on the space of discrete models. In this paper we develop a technique called “racing” that tests the set of models in parallel, quickly discards those models that are clearly inferior and concentrates the computational effort on differentiating among the better models. Racing is especially suitable for selecting among lazy learners since training requires negligible expense, and incremental testing using leave-one-out cross validation is efficient. We use racing to select among various lazy learning algorithms and to find relevant features in applications ranging from robot juggling to lesion detection in MRI scans.
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    Multicasting VP design methodology using simulated annealing in an ATM network (1996)
    Springer
    Journal of network and systems management 4 (1996), S. 133-153 
    Details
    ISSN: 1573-7705
    Keywords: High-speed network management ; ATM network management ; multipoint virtual paths design ; optimization ; simulated annealing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Multicast routing over semi-permanent VP (virtual path)s in an ATM (asynchronous transfer mode)-based B-ISDN (broadband integrated services digital network) determines a set of VPs connecting from a source node to destination nodes. The problem of finding the optimal constrained multicasting tree over the semi-permanent VPs in an ATM network is known to be NP (nondeterministic polynomial time)-complete. We develop an optimization methodology for searching a constrained multicast routing tree with minimum cost, using simulated annealing technique. We define the problem-dependent components such as state space and cost function, and refine the implementation-dependent factors including initial temperature and cooling schedule. The simulation results show that our optimization methodology demonstrates good behavior in terms of performance on a variety of graphs modeling the sample ATM networks.
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    URL: http://dx.doi.org/10.1007/BF02139131
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    A New Relaxation Procedure in the Hopfield Network for Solving Optimization Problems (1999)
    Springer
    Neural processing letters 10 (1999), S. 211-222 
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    ISSN: 1573-773X
    Keywords: constraint satisfaction ; Hopfield network ; neural networks ; optimization ; relaxation procedure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract When solving an optimization problem with a Hopfield network, a solution is obtained after the network is relaxed to an equilibrium state. The relaxation process is an important step in achieving a solution. In this paper, a new procedure for the relaxation process is proposed. In the new procedure, the amplified signal received by a neuron from other neurons is treated as the target value for its activation (output) value. The activation of a neuron is updated directly based on the difference between its current activation and the received target value, without using the updating of the input value as an intermediate step. A relaxation rate is applied to control the updating scale for a smooth relaxation process. The new procedure is evaluated and compared with the original procedure in the Hopfield network through simulations based on 200 randomly generated instances of the 10-city traveling salesman problem. The new procedure reduces the error rate by 34.6% and increases the percentage of valid tours by 194.6% as compared with the original procedure.
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    URL: http://dx.doi.org/10.1023/A:1018780424422
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    Training Reinforcement Neurocontrollers Using the Polytope Algorithm (1999)
    Springer
    Neural processing letters 9 (1999), S. 119-127 
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    ISSN: 1573-773X
    Keywords: reinforcement learning ; neurocontrol ; optimization ; polytope algorithm ; pole balancing ; genetic reinforcement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A new training algorithm is presented for delayed reinforcement learning problems that does not assume the existence of a critic model and employs the polytope optimization algorithm to adjust the weights of the action network so that a simple direct measure of the training performance is maximized. Experimental results from the application of the method to the pole balancing problem indicate improved training performance compared with critic-based and genetic reinforcement approaches.
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    URL: http://dx.doi.org/10.1023/A:1018669223478
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    Genetic Algorithms for Optimizing the Remediation of Contaminated Aquifer (2000)
    Springer
    Transport in porous media 41 (2000), S. 149-171 
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    ISSN: 1573-1634
    Keywords: hydrodynamic isolation ; plume ; remediation ; genetic algorithms ; optimization ; aquifer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Produced water constitutes a large amount of waste fluids during the production operation of an oil field. Underground injection for disposing the wastewater from hydrocarbon production is an engineering problem due to the possibility of leakage of injected pollutant material from receiving medium to a drinking water source. This paper describes a method for optimization of polluted aquifer remediation design using one of the artificial intelligence optimization methods, namely Genetic Algorithms (GAs). As a case study, the contaminated area was created by using a groundwater transport simulator, which is based on Method of Characteristics (MOC). Then, the developed computer program was run to find the optimum solution for remediation, and the solution yielded from the program was verified by using a groundwater simulator. The plume was captured and the concentration level of chloride ion within the aquifer was diminished by using extraction wells. The analytical model approach provided different alternatives for appropriate isolation of plume. GAs were used as an optimization technique for making a decision among the alternatives, by considering operation time, number of wells, pumping rate and drawdown as decision variables and constraints.
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    URL: http://dx.doi.org/10.1023/A:1006774101991
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    On Solving Aquifer Management Problems with Simulated Annealing Algorithms (1999)
    Springer
    Water resources management 13 (1999), S. 153-170 
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    ISSN: 1573-1650
    Keywords: Aquifer management ; infrastructure location ; least-cost design and operation ; optimization ; simulated annealing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract Aquifer systems play an essential role in meeting the ever increasing use of water for different purposes. Proper design and management of such systems should therefore be a very important matter of concern, not only to ensure that water will be available in adequate quantity (and quality) to satisfy demands but also to guarantee that this would be done in an optimal manner. This paper presents a model serving to define which water supply structures (especially pumping equipment and pipes) should be installed in order to minimize the sum of set-up costs and operation costs while satisfying demands, using a heuristic approach based on simulated annealing. Annealing algorithms are random local search optimization algorithms that allow, at least in theory and in probability, the determination of a global optimum of a (possibly constrained) function.
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    URL: http://dx.doi.org/10.1023/A:1008149626428
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    Model for real-time optimal flood control operation of a reservoir system (1990)
    Springer
    Water resources management 4 (1990), S. 21-46 
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    ISSN: 1573-1650
    Keywords: Flood control ; unsteady flow ; reservoir operation ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract A methodology and model have been developed for the real-time optimal flood operation of river-reservoir systems. This methodology is based upon combining a nonlinear programming model with a flood-routing simulation model within an optimal control framework. The generalized reduced gradient code GRG2 is used to perform the nonlinear optimization and the simulator is the U.S. National Wheather Service DWOPER code. Application of the model is illustrated through a case study of Lake Travis on the Lower Colorado River in Texas.
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    URL: http://dx.doi.org/10.1007/BF00429923
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    A sensitivity analysis and parametric study for the evaluation of the optimal management of a contaminated aquifer (1994)
    Springer
    Water resources management 8 (1994), S. 11-31 
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    ISSN: 1573-1650
    Keywords: Aquifer contamination ; groundwater quality management ; sensitivity analysis ; parametric study ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract A typical groundwater remedation problem is studied by using a combined simulation-optimization model. The management procedure employs groundwater flow and contaminant transport simulation models in conjunction with linear and quadratic programming techniques. The methodology is applied to the hydrodynamic control of a contaminant plume that has to be stabilized and removed by a system of pumping wells. The paper focuses mainly upon a sensitivity analysis to the aquifer transmissivity. The effect of changes in the transmissivities of a zoned aquifer upon the optimal solutions of the management problem is examined by considering the optimal pumping rates, the time to remediation and the pumped groundwater volume as the key output variables of the remediation strategies. In addition, the influence of the dispersivities and the imposed hydraulic gradient upon the same output variables is critically evaluated. The results of the study illustrate the need for uncertainty reduction in the knowledge of the hydrogeologic parameters.
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    URL: http://dx.doi.org/10.1007/BF00872277
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    Optimal allocation of surface water in regional water management (1994)
    Springer
    Water resources management 8 (1994), S. 137-153 
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    ISSN: 1573-1650
    Keywords: Regional water management ; surface water ; surface water supply capacity ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract Surface water is a scarce reource that is applied by various users for a variety of activities. The regulation of surface water use is an element of regional water management at various management levels. At each management level, the allocation of surface water supply capacity is a policy instrument. An optimization model has been formulated to support the evaluation of potential allocations at a particular management level. The model describes the allocation problem as a network, in which arcs represent waterways and nodes represent inlets and locations where there is a demand for surface water supply. The use of surface water for a specific activity at a specific node is referred to as an application, for example, for sprinkling, for use as cooling water, for dissolving effluent, and for conservation of environmental areas. The optimization model generates the optimal allocation of surface water and of surface water supply capacity. The operation of the model was demonstrated by a case study, where it was applied to maximize the expected revenues in agriculture (measured as value added).
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    URL: http://dx.doi.org/10.1007/BF00872433
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    Multiple-objective stochastic waste-load allocation (1992)
    Springer
    Water resources management 6 (1992), S. 117-133 
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    ISSN: 1573-1650
    Keywords: Waste-load allocation ; water-quality management ; multiple-objective analysis ; optimization ; uncertainty analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract The practice of waste-load allocation in water quality management involves several noncommensurate and conflicting objectives. In particular, the objectives considered in this multiobjective stochastic waste-load allocation study are (1) maximization of total waste discharge, (2) maximization of instream dissolved oxygen concentration, (3) minimization of difference in equity measures, and (4) maximization of reliability of water quality compliance. To demonstrate the analysis, the model was applied to an example involving six waste dischargers.
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    URL: http://dx.doi.org/10.1007/BF00872207
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    Genetic Algorithms for Optimal Operation of Soil Aquifer Treatment Systems (1998)
    Springer
    Water resources management 12 (1998), S. 375-396 
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    ISSN: 1573-1650
    Keywords: genetic algorithms ; groundwater recharge ; optimization ; soil aquifer treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract The genetic algorithm (GA) is a nonconventional search technique which is patterned after the biological processes of natural selection and evolution. It has the ability to search large and complex decision spaces and handle nonconvexities. In this paper, the genetic algorithm is investigated and applied to solve the optimal operation problem of soil aquifer treatment (SAT) systems. This problem involves finding optimal water application time and drying time which maximize infiltration for a predetermined starting influent rate of waste water and subject to various physical and operational constraints. A new scaling method is developed and some improvements on the evolution procedure are presented. A comprehensive GA–SAT computer model was developed and applied to an example SAT problem. The results are encouraging, when compared with using the successive approximation linear quadratic regulator algorithm. It was found that genetic algorithms are easy to program and interface with large complicated simulators.
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    URL: http://dx.doi.org/10.1023/A:1008030612068
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    A Planning Model for the Fuerte-Carrizo Irrigation System, Mexico (1997)
    Springer
    Water resources management 11 (1997), S. 165-184 
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    ISSN: 1573-1650
    Keywords: optimization ; linear programming ; simulation ; irrigation planning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract A methodology is presented for planning the operation of the Fuerte-Carrizo irrigation system in northwest Mexico. The system has two storage dams, two irrigation districts, and water transfer capabilities between both dams. The methodology uses a combination of linear programming (LP) and simulation. The LP model maximizes the net return of the farmers, subject to restrictions of the system, availability of water and land, and water transfer relationships. The simulation model is programmed as a microcomputer interactive package simulating the performance of the system. The methodology has proven to be a useful tool to assist those responsible for the operation of the irrigation system.
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    URL: http://dx.doi.org/10.1023/A:1007910530591
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    Multireservoir System Optimization using Fuzzy Mathematical Programming (2000)
    Springer
    Water resources management 14 (2000), S. 457-472 
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    ISSN: 1573-1650
    Keywords: fuzzy mathematical programming ; multireservoir system ; optimization ; steady state solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract For a multireservoir system, where the number of reservoirs islarge, the conventional modelling by classical stochastic dynamicprogramming (SDP) presents difficulty, due to the curse ofdimensionality inherent in the model solution. It takes a longtime to obtain a steady state policy and also it requires largeamount of computer storage space, which form drawbacks inapplication. An attempt is made to explore the concept of fuzzysets to provide a viable alternative in this context. Theapplication of fuzzy set theory to water resources systems isillustrated through the formulation of a fuzzy mathematicalprogramming model to a multireservoir system with a number ofupstream parallel reservoirs, and one downstream reservoir. Thestudy is aimed to minimize the sum of deviations of the irrigationwithdrawals from their target demands, on a monthly basis, over ayear. Uncertainty in reservoir inflows is considered by treatingthem as fuzzy sets. The model considers deterministic irrigationdemands. The model is applied to a three reservoir system in theUpper Cauvery River basin, South India. The model clearlydemonstrates that, use of fuzzy linear programming inmultireservoir system optimization presents a potentialalternative to get the steady state solution with a lot lesseffort than classical stochastic dynamic programming.
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    URL: http://dx.doi.org/10.1023/A:1011117918943
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    Two-step dynamic programming approach for optimal irrigation water allocation (1990)
    Springer
    Water resources management 4 (1990), S. 187-204 
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    ISSN: 1573-1650
    Keywords: Dynamic programming ; irrigation management ; optimization ; production function ; stochastic model ; water allocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract A two-step (deterministic and stochastic) dynamic programming approach has been introduced in this study to solve the complex problem of optimal water allocation in a run-of-the-river-type irrigation project. The complexity of a real-world situation is represented by incorporating in the optimization model the stochasticity of water supply and the nonlinearity of crop production functions. A nonlinear, dated, and multiplicative production function is transformed into a sequentially additive type to replace the usual method of creating an additional ‘state of the plant variable’ which only increases the dimension of the problem. As compared to the explicit stochastic dynamic programming which necessitates, along with its use, an enormous computational complexity due to the so-called ‘curse of dimensionality’, the present model can approximate the theoretical global optimum, at least for the present case study, with a dramatic reduction in computer processing time. It also eliminates the rigidity of the policy derived by the explicit approach, since it provides irrigation planners with alternative decision policies which incorporate intangibles and other nonengineering factors. The traditional method of fixing the cropping pattern based on deterministic estimates of a dependable water supply can likewise be evaluated by the use of the present model. The results of the model's application appear to be practically acceptable.
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    URL: http://dx.doi.org/10.1007/BF00431143
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    Selecting risk levels in chance-constrained reservoir operation modeling: A fuzzy set approach (1991)
    Springer
    Water resources management 4 (1991), S. 251-271 
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    ISSN: 1573-1650
    Keywords: Reservoir operation ; treatment of imprecision ; optimization ; satisficing ; fuzzy sets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract Many modifications, extensions, discussions, and evaluations of chance-constrained reservoir operating models have been reported in the technical literature. Lack of economic data and the fact that the establishment of acceptable risk levels in these types of models involves a human factor with all its vagueness of perception, subjectivity, and attitudes may not permit proper application of either reliability or multiobjective programming approaches. This paper presents a unique methodology for handling a practical problem of selecting risk levels in chance-constrained reservoir operation modeling. The proposed methodology is based on fuzzy set theory. Two types of fuzzy sets are used in the formulation of the reservoir long-term planning model, one for constraints and one for the objective function. An iterative solution algorithm for deriving an optimal decision using fuzzy set operations and the chance-constrained approach is developed and presented. A practical application of the approach demonstrates the feasibility and efficiency of both the proposed approach and its iterative search procedure for selecting risk levels in chance-constrained reservoir modeling.
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    URL: http://dx.doi.org/10.1007/BF00430340
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    Optimal allocation of water resources in large river basins: I. Theory (1995)
    Springer
    Water resources management 9 (1995), S. 39-51 
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    ISSN: 1573-1650
    Keywords: multiobjective ; optimization ; systems engineering ; water resources allocation ; Hierarchical dynamic programming ; subregion ; trunk stream ; basin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract The major purpose of this paper is to present the useful techniques in the optimal allocation of water resources (OAWR) and to demonstrate using water resources applications how these methods can be conveniently employed in practice for systematically studying both simple and complex water resources problems. Formal modelling techniques in multiobjective decision-making provide many benefits to professionals working in water resources and elsewhere. A new Large-system Hierarchical Dynamic Programming (LHDP) method to solve the model can be carried out to ascertain the consequences of meaningful parameter changes upon the optimal or compromise solution. As a case study, the techniques and methods are applied to the OAWR of the Yellow River Basin (YRB) of China. The next paper shares with the reader recent research results on the OAWRYRB.
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    URL: http://dx.doi.org/10.1007/BF00877388
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    Modeling complex reservoir geometries with multiple-point statistics (1996)
    Springer
    Mathematical geology 28 (1996), S. 895-907 
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    ISSN: 1573-8868
    Keywords: reservoir geometry ; multiple-point histogram ; geological accretion ; optimization ; flow responses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Large-scale reservoir architecture constitutes first-order reservoir heterogeneity and dietates to a large extent reservoir flow behavior. It also manifests geometric characteristics beyond the capability of traditional geostatistical models conditioned only on single-point and two-point statistics. Multiple-point statistics, as obtained by scanning a training image deemed representative of the actual reservoir, if reproduced properly provides stochastic models that better capture the essence of the heterogeneity. A “growth” algorithm, coupled with an optimization procedure, is proposed to reproduce target multiple-point histograms. The growth algorithm makes an analogy between geological accretion process and stochastic process and amounts to restricting the random path of sequential simulation at any given stage to a set of eligible nodes (immediately adjacent to a previously simulated node or sand grain). The proposed algorithm, combined with a multiple-grid approach, is shown to reproduce effectively the geometric essence of complex training images exhibiting long-range and curvilinear structures. Also, by avoiding a rigorous search for global minimum and accepting local minima, the proposed algorithm improves CPU time over traditional optimization procedures by several orders of magnitude. Average flow responses run on simulated realizations are shown to bracket correctly the reference responses of the training image.
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    URL: http://dx.doi.org/10.1007/BF02066007
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    Gradual Deformation and Iterative Calibration of Gaussian-Related Stochastic Models (2000)
    Springer
    Mathematical geology 32 (2000), S. 87-108 
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    ISSN: 1573-8868
    Keywords: heterogeneity ; geostatistics ; optimization ; inversion ; nonlinearity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract This paper describes a new method for gradually deforming realizations of Gaussian-related stochastic models while preserving their spatial variability. This method consists in building a stochastic process whose state space is the ensemble of the realizations of a spatial stochastic model. In particular, a stochastic process, built by combining independent Gaussian random functions, is proposed to perform the gradual deformation of realizations. Then, the gradual deformation algorithm is coupled with an optimization algorithm to calibrate realizations of stochastic models to nonlinear data. The method is applied to calibrate a continuous and a discrete synthetic permeability fields to well-test pressure data. The examples illustrate the efficiency of the proposed method. Furthermore, we present some extensions of this method (multidimensional gradual deformation, gradual deformation with respect to structural parameters, and local gradual deformation) that are useful in practice. Although the method described in this paper is operational only in the Gaussian framework (e.g., lognormal model, truncated Gaussian model, etc.), the idea of gradually deforming realizations through a stochastic process remains general and therefore promising even for calibrating non-Gaussian models.
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    URL: http://dx.doi.org/10.1023/A:1007506918588
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    The role of multi-objective optimization in negotiation and mediation support (1993)
    Springer
    Theory and decision 34 (1993), S. 201-214 
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    ISSN: 1573-7187
    Keywords: Negotiation ; multi-objective modeling ; optimization ; mediation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology , Economics
    Notes: Abstract The paper reviews the methodology of multi-objective modeling and optimization used in decision support based on computerized analytical models (as opposed to logical models used in expert systems) that represent expert knowledge in a given field. The essential aspects of this methodology relate to its flexibility: modeling and optimization methods are treated not as goals in themselves but as tools that help a sovereign user (an analyst or a decision maker) to interact with the model, to generate and analyze various decision options, to learn about possible outcomes of these decisions. Although the applications of such methods in negotiation and mediation support is scarce yet, their flexibility increases essentially the chances of such applications. Various aspects of negotiation and mediation methods related to multi-objective optimization and game theory are also reviewed. A possible application of the MCBARG system for supporting negotiation related to the acid rain problem is briefly summarized.
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    URL: http://dx.doi.org/10.1007/BF01075189
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    Genetic algorithms and scatter search: unsuspected potentials (1994)
    Springer
    Statistics and computing 4 (1994), S. 131-140 
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    ISSN: 1573-1375
    Keywords: Genetic algorithms ; scatter search ; optimization ; mathematical relaxation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract We provide a tutorial survey of connections between genetic algorithms and scatter search that have useful implications for developing new methods for optimization problems. The links between these approaches are rooted in principles underlying mathematical relaxations, which became inherited and extended by scatter search. Hybrid methods incorporating elements of genetic algorithms and scatter search are beginning to be explored in the literature, and we demonstrate that the opportunity exists to develop more advanced procedures that make fuller use of scatter search strategies and their recent extensions.
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    URL: http://dx.doi.org/10.1007/BF00175357
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    Automatic starting point selection for function optimization (1994)
    Springer
    Statistics and computing 4 (1994), S. 173-177 
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    ISSN: 1573-1375
    Keywords: Maximum likelihood ; mixture models ; simulated annealing ; optimization ; hybrid algorithm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Traditional (non-stochastic) iterative methods for optimizing functions with multiple optima require a good procedure for selecting starting points. This paper illustrates how the selection of starting points can be made automatically by using a method based upon simulated annealing. We present a hybrid algorithm, possessing the accuracy of traditional routines, whilst incorporating the reliability of annealing methods, and illustrate its performance for a particularly complex practical problem.
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    URL: http://dx.doi.org/10.1007/BF00142569
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    Some Remarks on the Equivalence between 2D and 3D Classical Snakes and Geodesic Active Contours (1999)
    Springer
    International journal of computer vision 34 (1999), S. 19-28 
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    ISSN: 1573-1405
    Keywords: geodesic active contours ; active surfaces ; Hamiltonian ; snakes ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Recently, Caselles et al. have shown the equivalence between a classical snake problem of Kass et al. and a geodesic active contour model. The PDE derived from the geodesic problem gives an evolution equation for active contours which is very powerfull for image segmentation since changes of topology are allowed using the level set implementation. However in Caselles' paper the equivalence with classical snake is only shown for 2D images and 1D curves, by using concepts of Hamiltonian theory which have no meanings for active surfaces. This paper propose to examine the notion of equivalence and to revisite Caselles et al. arguments. Then a notion equivalence is introduced and shown for classical snakes and geodesic active contours in the 2D (active contour) and 3D (active surface) case.
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    URL: http://dx.doi.org/10.1023/A:1008168219878
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    Optimizing Environmental Product Life Cycles (1997)
    Springer
    Environmental and resource economics 9 (1997), S. 199-224 
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    ISSN: 1573-1502
    Keywords: environmental policy ; pulp and paper ; life cycle ; optimization ; technology lock-in ; recycling ; geography of production ; environment-trade conflict
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract In this paper, we propose a methodology, based on materials accounting and operational research techniques, to assess different industry configurations according to their life cycle environmental impacts. Rather than evaluating a specific technology, our methodology searches for the feasible configuration with the minimum impact. This approach allows us to address some basic policy-relevant questions regarding technology choice, investment priorities, industrial structures, and international trade patterns. We demonstrate the methodology in the context of the European pulp and paper industry. We are able to show that current environmental policy's focus on maximizing recycling is optimal now, but that modest improvements in primary pulping technology may shift the optimal industry configuration away from recycling toward more primary pulping with incineration. We show that this will have significant implications for the amount and type of environmental damage, for the location of different stages in the production chain, and for trade between European member states. We caution policy makers that their single-minded focus on recycling may foreclose investment in technologies that could prove environmentally superior. Finally, we hint that member state governments may be fashioning their environmental policy positions at least in part on some of the trade and industrial implications we find.
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    URL: http://dx.doi.org/10.1023/A:1026423929606
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    Guided Local Search for Solving SAT and Weighted MAX-SAT Problems (2000)
    Springer
    Journal of automated reasoning 24 (2000), S. 205-223 
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    ISSN: 1573-0670
    Keywords: SAT problem ; local search ; meta-heuristics ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper, we show how Guided Local Search (GLS) can be applied to the SAT problem and show how the resulting algorithm can be naturally extended to solve the weighted MAX-SAT problem. GLS is a general, penalty-based meta-heuristic, which sits on top of local search algorithms to help guide them out of local minima. GLS has been shown to be successful in solving a number of practical real-life problems, such as the traveling salesman problem, BT"s workforce scheduling problem, the radio link frequency assignment problem, and the vehicle routing problem. We present empirical results of applying GLS to instances of the SAT problem from the DIMACS archive and also a small set of weighted MAX-SAT problem instances and compare them with the results of other local search algorithms for the SAT problem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006343127545
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    Optimal flood control in multireservoir cascade systems with deterministic inflow forecasts (1993)
    Springer
    Water resources management 7 (1993), S. 207-223 
    Details
    ISSN: 1573-1650
    Keywords: Flood control ; multireservoir systems ; optimization ; aggregation and disaggregation ; coordinated operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract This article presents the formal analysis of a problem of the optimal flood control in systems of serially connected multiple water reservoirs. It is assumed, that the basic goal is minimization of the peak flow measured at a point (cross-section) located downstream from all reservoirs and that inflows to the system are deterministic. A theorem expressing sufficient conditions of optimality for combinations of releases from the reservoirs is presented together with the relevant proof. The main features of the optimal combinations of controls are thoroughly explained. Afterwards, two methods of determining the optimal releases are presented. Finally, the results of the application of the proposed methodology to a small, four reservoir system are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01675304
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    Simple Daily Dynamic Adaptive Operation Rules for WaterResources Optimization (2000)
    Springer
    Water resources management 14 (2000), S. 349-368 
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    ISSN: 1573-1650
    Keywords: adaptive ; dynamic ; management ; optimization ; reservoir ; SCADA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract In large metropolitan areas of the world the operation andmanagement programs for water supply reservoirs play adominant role in economic, social and cultural growth anddevelopment. An unprecedented population increase inaddition to intensive migration from rural areas add extrapressure on the available limited natural resources suchas land, air and water. Although there are many optimizationtechniques including simple linear or dynamic programming whichmight also include chance constraints, they are rather sophisticated for layman operators who deal with the real timejoint operation of various reservoirs. Furthermore, these operation programs require data on daily basis on hydrologicvariable such as rainfall, runoff, evaporation and others which might not be available in sufficient amounts. It is, therefore, necessary to develop simple, dynamic and adaptiveoperation rules according to the special set up of thereservoirs for each city water resources. This article providesthe fundamentals of Istanbul city water-supply-reservoir operation rules suitable for the combination of already existing Supervised Control And DataAcquisition (SCADA) unit of the city. The operation rules are developed on daily basis under the worstpossible constraints to appear. The suggested model is namedSimple Adaptive Daily Dynamic Program (SADP which runs on the concept of critical duration with unpredictable rainfall-runoff, evaporation and infiltration properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011176407993
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    Numerical Study of Processes in the Cavity of the 170 GHz Gyrotron for ITER Operating at the TE25.10 Mode (2000)
    Springer
    International journal of infrared and millimeter waves 21 (2000), S. 1381-1395 
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    ISSN: 1572-9559
    Keywords: gyrotrons ; optimization ; mode competition ; start-up ; recovery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The opportunity of use of a TE25.10 operating mode for CW 170 GHz/1 MW gyrotron for ITER is estimated. Parameters are optimized to achieve maximum efficiency of the gyrotron with an acceptable Ohmic load on the cavity. The influence of unwanted mode conversion at the output of the resonator, mode competition, electron beam potential depression, ion compensation of the space charge and beam energy recovery is investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026448822363
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    Simultaneous Optimization as a Method to Establish Generalized Functional Forms for Empirical Equations of State (1998)
    Springer
    International journal of thermophysics 19 (1998), S. 491-500 
    Details
    ISSN: 1572-9567
    Keywords: equations of state ; optimization ; nonpolar fluids ; methane ; argon ; oxygen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new algorithm for the optimization of functional forms of empirical equations of state is presented which considers data sets of different substances simultaneously. In this way, functional forms for empirical equations of state can be developed which yield, on average, the best representation of the thermo-dynamic properties of all substances within larger groups of substances (e.g., “nonpolar” and “polar” substances). The new algorithm is being used to develop a new class of empirical equations of state which meet typical technical requirements on the accuracy of thermodynamic properties with only about 10 fittable coefficients. The first results for nonpolar fluids are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022573729698
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    A Note on Error Bounds for Convex and Nonconvex Programs (1999)
    Springer
    Computational optimization and applications 12 (1999), S. 41-51 
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    ISSN: 1573-2894
    Keywords: convex programming ; optimization ; duality ; error bounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Given a single feasible solution $$x_F $$ and a single infeasible solution $$x_I $$ of a mathematical program, we provide an upper bound to the optimal dual value. We assume that $$x_F $$ satisfies a weakened form of the Slater condition. We apply the bound to convex programs and we discuss its relation to Hoffman-like bounds. As a special case, we recover a bound due to Mangasarian [11] on the distance of a point to a convex set specified by inequalities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008659512824
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    Portfolio management with stable distributions (2000)
    Springer
    Mathematical methods of operations research 51 (2000), S. 341-352 
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    ISSN: 1432-5217
    Keywords: Key words: Stable ditributions ; portfolio management ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract. The aim of this short review is to outline the main directions of stable Paretian modeling in portfolio management.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001860050092
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    On quadratic hedging in continuous time (2000)
    Springer
    Mathematical methods of operations research 51 (2000), S. 315-339 
    Details
    ISSN: 1432-5217
    Keywords: Key words: Incomplete market ; quadratic hedging ; optimization ; semimartingales ; stochastic integrals ; Kunita-Watanabe projection ; L2-projection ; minimal martingale measure ; variance-optimal martingale measure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract. We review the main results in the theory of quadratic hedging in a general incomplete model of continuous trading with semimartingale price process. The objective is to hedge contingent claims by using portfolio strategies. We describe two types of criteria: the so-called (local) risk-minimization and the mean-variance approaches. From a mathematical viewpoint, these optimization problems lead to new variants of decomposition theorems in stochastic analysis.
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    URL: http://dx.doi.org/10.1007/s001860050091
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    Optimization of the take-off movement of ski jumping with the method of mathematical programming (1992)
    Springer
    Applied mathematics and mechanics 13 (1992), S. 669-674 
    Details
    ISSN: 1573-2754
    Keywords: mathematical programming ; optimization ; dynamics of systems of rigid bodies ; ski jumping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract This paper is based on the finite and dispersed data which were obtained from the experiments of the wind tunnel and of the force measurement and from the high-speed photography. It analyses and optimizes the take-off movement of ski jumping with the theory of dynamics of systems of rigid bodies and with the method of mathematical programming. The paper describes the optimal take-off movement of ski jumping. Furthermore, it presents an example and compares the result with those of other papers published at home and abroad. The comparison shows that our computation and optimization are reasonable and well-grounded.
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    URL: http://dx.doi.org/10.1007/BF02456091
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    The limiting stokes wave with finite water depth (1993)
    Springer
    Applied mathematics and mechanics 14 (1993), S. 887-889 
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    ISSN: 1573-2754
    Keywords: Stokes wave ; limiting wave ; optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract In this paper we extend the method developed in [1] for limiting Stokes wave of infinite water depth to cover the case of finite depth. The method has high efficiency and the result is accurate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02457484
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    Topology optimization design of continuum structures under stress and displacement constraints (2000)
    Springer
    Applied mathematics and mechanics 21 (2000), S. 19-26 
    Details
    ISSN: 1573-2754
    Keywords: structure ; optimization ; topology optimization ; modeling ; dual programming ; O223 ; TU323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Mathematics , Physics
    Notes: Abstract Topology optimization design of continuum structures that can take account of stress and displacement constraints simultaneously is difficult to solve at present. The main obstacle lies in that, the explicit function expressions between topological variables and stress or displacement constraints can not be obtained using homogenization method or variable density method. Furthermore, large quantities of design variables in the problem make it hard to deal with by the formal mathematical programming approach. In this paper, a smooth model of topology optimization for continuum structures is established which has weight objective considering stress and displacement constraints based on the independent-continuous topological variable concept and mapping transformation method proposed by Sui Yunkang and Yang Deqing. Moreover, the approximate, explicit expressions are given between topological variables and stress or displacement constraints. The problem is well solved by using dual programming approach, and the proposed element deletion criterion implements the inversion of topology variables from the discrete to the continuous. Numerical examples verify the validity of proposed method.
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    URL: http://dx.doi.org/10.1007/BF02458535
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    Convergence of the Nonmonotone Perry and Shanno Method for Optimization (2000)
    Springer
    Computational optimization and applications 16 (2000), S. 159-172 
    Details
    ISSN: 1573-2894
    Keywords: optimization ; conjugate gradient method ; global convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper a new nonmonotone conjugate gradient method is introduced, which can be regarded as a generalization of the Perry and Shanno memoryless quasi-Newton method. For convex objective functions, the proposed nonmonotone conjugate gradient method is proved to be globally convergent. Its global convergence for non-convex objective functions has also been studied. Numerical experiments indicate that it is able to efficiently solve large scale optmization problems.
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    URL: http://dx.doi.org/10.1023/A:1008753308646
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