ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A graphical investigation of error bounds for moment-based queueing approximations (1991)
    Springer
    Queueing systems 8 (1991), S. 295-312 
    Details
    ISSN: 1572-9443
    Keywords: Error bounds ; moment matching ; queueing approximations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Many approximations of queueing performance measures are based on moment matching. Empirical and theoretical results show that although approximations based on two moments are often accurate, two-moment approximations can be arbitrarily bad and sometimes three-moment approximations are far better. In this paper, we investigate graphically error bounds for two- and three-moment approximations of three performance measures forGI/M/ · type models. Our graphical analysis provides insight into the adequacy of two- and three-moment approximations as a function of standardized moments of the interarrival-time distribution. We also discuss how the behavior of these approximations varies with other model parameters and with the performance measure being approximated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02412257
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Descriptors of arrival-process burstiness with application to the discrete Markovian arrival process (1996)
    Springer
    Queueing systems 23 (1996), S. 107-130 
    Details
    ISSN: 1572-9443
    Keywords: Burstiness ; arrival process ; discrete Markovian arrival process ; matrix-analytic methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We use the concept of burstiness to propose new descriptors of arrival processes or, more generally, point or traffic processes. We say that the arrival process is in aburst when its interarrival times are less than or equal to some threshold value; during periods in which interarrival times are greater than the threshold value, the process is in agap. We propose to describe the arrival process in terms of the number of arrivals during a burst (gap) and the duration of a burst (gap). For the case of discrete-time Markovian arrival processes we derive the distribution of the number of arrivals during a burst (gap) and the mean duration of a burst (gap). We present numerical results to illustrate how our descriptors can be used to understand the behavior of an arrival process and the congestion it induces in a queueing system. We also report the results of an experiment which shows a statistical relationship between two of our descriptors and a measure of queueing congestion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01206553
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    An investigation of phase-distribution moment-matching algorithms for use in queueing models (1991)
    Springer
    Queueing systems 8 (1991), S. 129-147 
    Details
    ISSN: 1572-9443
    Keywords: Approximations ; moment matching ; queueing approximations ; error bounds ; phase distributions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Algorithms for matching moments to phase-type distributions are evaluated on the basis of their performance in their intended application, queueing models. The moment-matching algorithms under consideration match two moments to a hyperexponential distribution with balanced means and three moments to a mixture of two Erlang distributions of common order. These algorithms are used to approximate an interarrival-time distribution for a queueing model, and the accuracy of associated performance-measure approximations is then used to evaluate the moment-matching algorithms. Three performance measures are considered, and attention is focussed on the steady-state mean queue length (number in system) of theGI/M/1 queue. Performance-measure approximations are compared to three-moment bounds and performance-measure values arising from hypothetical approximated distributions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02412246
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Photopigment and receptor properties in Drosophila compound eye and ocellar receptors (1979)
    Springer
    European biophysics journal 5 (1979), S. 197-209 
    Details
    ISSN: 1432-1017
    Keywords: Visual pigments ; Invertebrate neurobiology ; Membrane biophysics ; Retina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract A review of the spectral sensitivity and the rhodopsin and metarhodopsin characteristics in three compound eye receptor types (R1–6, R7, and R8) and ocellar receptors is presented (Fig. 1). Photopigment properties were determined from measures of conversion efficiency. The photopigments of R1–6 were studied using in vivo microspectrophotometry in the deep pseudopupil of white-eyed flies. These studies yielded a refined estimate of the R1–6 metarhodopsin spectrum (Fig. 2). The quantum efficiency relative to the spectral sensitivity estimate of the rhodopsin spectrum was factored out. The quantum efficiency of rhodopsin is about 1.75 times that of metarhodopsin. The peak absorbance of metarhodopsin was estimated to be about 2.6 times that of rhodopsin. The mechanism of the two-peaked R1–6 spectral sensitivity and metarhodopsin spectrum is discussed in terms of evidence that there is only one rhodopsin in R1–6 and that vitamin A deprivation preferentially lowers ultraviolet sensitivity. The prolonged depolarizing afterpotential is reviewed from the standpoint of the internal transmitter hypothesis of visual excitation. A careful comparison of the intensity-responsivity for photopigment conversion and its adaptional consequences is made (Fig. 3).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535448
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Microspectrophotometry ofDrosophila visual pigments: Determinations of conversion efficiency in R1–6 receptors (1980)
    Springer
    Journal of comparative physiology 140 (1980), S. 275-286 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We used microspectrophotometry, together with some associated electrophysiological measurements, to characterize the photopigments of R1–6 receptors in living, white-eyedDrosophila. Measurements were from the deep pseudopupil, an optical visualization of photopigment-containing rhabdomeres. Transmission changes associated with photointerconversion of rhodopsin (R480) and its stable metarhodopsin (M570) are easily seen (Fig. 1). Such transmission changes were measured to produce a difference specrum (Fig. 2); the isosbestic wavelength is about 502 nm. A photoequilibrium spectrum (Fig. 3), analyzed together with sensitivity data (Fig. 4a), was used to determine the fraction of M570 in photoequilibria established with various monochromatic wavelengths. From this, the quantum efficiency for M570 to R480 conversion relative to R480 to M570 efficiency was determined to be about 0.71. No dark regeneration of M570 to R480 occurred within a period of 60min (Fig. 4a, b). The extent of conversion related to incident energy was estimated as a function of wavelength (Figs. 5 and 6). These experiments yielded the photosensitivity spectrum of the visual pigment (Fig. 6). Assuming that the absorption spectrum of rhodopsin (R480) is the same as the sensitivity spectrum as determined by electrophysiology, this photosensitivity spectrum was used to derive the spectrum of metarhodopsin (M570) (Fig. 7). The maximal extinction of M570 is about 1.43 times the maximal extinction of R480. The spectra of both states of the photopigment fit the Ebrey-Honig nomogram in the long wavelength band. Both of the photosensitivity spectra, measured in the living eye, associated with R480 and M570 respectively have a major UV maximum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606268
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Estimating and simulating Poisson processes having trends or multiple periodicities (1997)
    Springer
    IIE transactions 29 (1997), S. 201-211 
    Details
    ISSN: 1573-9724
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We develop and evaluate procedures for estimating and simulating nonhomogeneous Poisson processes having an exponential rate function, where the exponent may include a polynomial component or some trigonometric components or both. Maximum likelihood estimates of the unknown continuous parameters of the rate function are obtained numerically, and the degree of the polynomial rate component is determined by a likelihood ratio test. The experimental performance evaluation for this estimation procedure involves applying the procedure to 100 independent replications of nine selected point processes that possess up to four trigonometric rate components together with a polynomial rate component whose degree ranges from zero to three. On each replication of each process, the fitting procedure is applied to estimate the parameters of the process; and then the corresponding estimates of the rate and mean-value functions are computed over the observation interval. Evaluation of the fitting procedure is based on plotted tolerance bands for the rate and mean-value functions together with summary statistics for the maximum and average absolute estimation errors in these functions computed over the observation interval. The experimental results provide substantial evidence of the numerical stability and usefulness of the fitting procedure in simulation applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018567028064
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Design of loading policies for a high-performance computer system (1997)
    Springer
    IIE transactions 29 (1997), S. 245-254 
    Details
    ISSN: 1573-9724
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We use a systematic simulation study of computer-system loading policies to design a loading policy for a high-performance system. Our results illustrate the performance advantages of ‘round-robin’ disciplines, the interference caused by finite memory, and how this interference can be mitigated by using carefully selected loading policies that exploit information about job resource requirements. Our choice of performance measures allows us to assess response-time predictability and fairness as well as overall efficiency. Using the insights obtained from our study, we introduce a new type of policy, the NEST policy, which is structured to employ the principles of good scheduling, while avoiding shortcomings of commonly used approaches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018575329881
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    facet.materialart.
    Unknown
    Photopigment and receptor properties in Drosophila compound eye and ocellar receptors (1979)
    Springer
    Details
    Publication Date: 1979-01-01
    Print ISSN: 0175-7571
    Electronic ISSN: 1432-1017
    Topics: Biology , Physics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Dendrimers Target the Ischemic Lesion in Rodent and Primate Models of Nonarteritic Anterior Ischemic Optic Neuropathy (2016)
    Public Library of Science
    Details
    Publication Date: 2016-04-29
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
    Published by Public Library of Science
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Incidence and antimicrobial susceptibility fingerprints of Plesiomonas shigelliodes isolates in water samples collected from some freshwater resources in Southwest Nigeria (2019)
    Elsevier
    Details
    Publication Date: 2019-05-01
    Print ISSN: 0048-9697
    Electronic ISSN: 1879-1026
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...