23,093 results for 2000

  • Calendar 2000

    Victoria University of Wellington (Wellington, N.Z.) (2000)

    Scholarly text
    Victoria University of Wellington

    Victoria University calendar for 2000.

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  • Kinectin participates in microtubule-dependent hormone secretion in pancreatic islet beta-cells

    Bai, Jizhong; Mon, Y; Krissansen, Geoffrey (2006)

    Journal article
    The University of Auckland Library

    We investigated roles of KNT and isoform KNTvd4 in the transport of amylin, insulin-containing secretory vesicles in RINm5F cells. Results suggest that both KNT and KNTvd4 participate in microtubule-dependent secretion of amylin in islet ??-cells.

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  • Correction: In Arroll B, Kenealy T, Kerse N.(2003) Do delayed prescriptions reduce antibiotic use in respiratory tract infections? A systematic review (Br J Gen Pract 2003; 53: 871???877)

    Arroll, Bruce; Kenealy, Timothy; Kerse, Ngaire (2004-02)

    Journal article
    The University of Auckland Library

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  • A technique for collecting and examining a large number of eggs

    Acosta, Monica L; Go??i, B (2000-07)

    Journal article
    The University of Auckland Library

    When examining egg hatchability in relation to the genetic background and age of the parental flies, it is necessary to examine a large number of eggs and also to minimize factors that may affect the egg hatchability. It is known that the availability of food affects the female fecundity (David et al., 1971), so it is important to keep the parental flies well fed during the egg collection period. In this communication, we present an easy way of manipulating flies and collecting their eggs without harassment. A disposable egg collection container made of a Blue MaxTM 50 ml polypropylene conical tube (30 mm diameter Falcon tubes, Becton Dickinson Labware) was adapted as follows: the tube is cut to its conical base and replaced by a ???soft drink??? plastic cap (only a few brands do not fit). The screw end of the tube is then sealed with a cotton or sponge cork. The plastic caps are partially filled with the agar-apple juice egg collection medium reported by N??sslein-Volhard and Wieschaus (1986) to which Methylene blue or another vital stain is added to improve the visualization of the eggs. A few grains of dry yeast are also added to the medium before its solidification in the caps. When applying the yeast in this way, the grains are deep in the solidifying medium and do not become viscose, still allowing the visualization of the eggs. The females can be kept well fed during the egg collection period since the plastic caps can be replaced daily or at shorter intervals. For the collection or replacement of the plastic caps, the flies are gently shaken into the cork end of the tube. The eggs can now be collected from the medium with a thin needle and further incubated on humid paper placed in a chamber at 25??C (Roberts, 1986). We found it useful to count the eggs directly in the caps, and further incubate the caps in a humid Tupperware chamber at 25??C. After 24 hours from the collection time, the eggs that have not hatched are examined under a stereomicroscope or microscope in a drop of Voltaleff oil to check the stage of death (N??sslein-Volhard and Wieschaus ,1986).

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  • Short- and long-term enzymatic regulation secondary to metabolic insult in the rat retina

    Acosta Etchebarne, Monica; Kalloniatis, Michael (2005-03)

    Journal article
    The University of Auckland Library

    Changes in oxygen and/or glucose availability may result in altered levels of ATP production and amino acid levels, and alteration in lactic acid production. However, under certain metabolic insults, the retina demonstrates considerable resilience and maintains ATP production, and/or retinal function. We wanted to investigate whether this resilience would be reflected in alterations in the activity of key enzymes of retinal metabolism, or enzymes associated with amino acid production that may supply their carbon skeleton for energy production. Enzymatic assays were conducted to determine the activity of key retinal metabolic enzymes total ATPase and Na+/K+-ATPase, aspartate aminotransferase and lactate dehydrogenase. In vitro anoxia led to an increase in retinal lactate dehydrogenase activity and to a decrease in retinal aspartate aminotransferase activity, without significant changes in Na+/K+-ATPase activity. In vivo inhibition of glutamine synthetase resulted in a short-term significant decrease in retinal aspartate aminotransferase activity. An increase in retinal aspartate aminotransferase and lactate dehydrogenase activities was accompanied by altered levels of amino acids in neurons and glia after partial inhibition of glial metabolism, implying that short- and long-term up- and down-regulation of key metabolic enzymes occurs to supply carbon skeletons for retinal metabolism. ATPase activity does not appear to fluctuate under the metabolic stresses employed in our experimental procedures.

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  • The darker side of the moon: Satanic traditions in New Zealand as magick systems

    Latham, John (2001)

    Masters thesis
    Victoria University of Wellington

    When people discover the topic of my thesis they usually ask "Why Satanism?". In 1998 Satanism caught my attention when I was doing an undergraduate paper in sociology, the sociology of religion. Here I encountered several studies on the Satanic Ritual Abuse phenomena (SRA, also known as Satanic Panic and Satanism scare) See appendices for a brief history of SRA of the late 1980's and early 1990's in England, America, Australia and here in New Zealand. SRA evolved from accusations that satanic cults were involved in rituals where children were physically and sexually abused, and possibly killed. There were also reports that children were being bred for such practices. Both here and overseas cases were investigated by government agencies. The Peter Ellis case is perhaps the defining example of SRA in New Zealand. See appendices for an overview of this case In 1999,I noticed the census figures between 1986 and 1996 showed a growth of New Zealanders who identified as Satanist during the height of SRA scare, with the number rising nearly 400% (from 240 to 906). From this several questions arose: perhaps most importantly what is Satanism: why had this number grown: and how does one become a Satanist? As I began researching answers to these questions, I became aware of elements that were not apparent from the literature. Not all Satanism is about being evil and using black Magick. The spelling of Magick with a 'k' is to differentiate between religious Magick and show (illusional) magic. This is explained in more detail later. Some elements of Satanism link it closely with other Magick traditions. In this thesis I discuss two questions: what is Satanism in New Zealand and is there a relationship between Satanism and other Magick traditions in New Zealand?

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  • A Pure-Java Group Communication Framework

    Cook, Carl; Churcher, Neville (2003)

    Doctoral thesis
    University of Canterbury Library

    This report presents the caise.messaging group communication framework— a simple Java-based Api developed as the networking component for a collaborative software engineering architecture. The framework is intended to be used as the communication layer for any distributed and/or collaborative systems that have communication requirements beyond simple point-to-point networking, but do not require the services or overheads of fully-featured groupware toolkits. The caise.messaging framework allows groups of remote applications to communicate with each other in the most simple manner as possible. The result is an Api that makes every participating application appear local to the calling application, providing communication within the application group by way of conventional method calls. This report presents an overview of the caise.messaging framework, including a background on existing communication technologies, the motivation for a new framework, a summary of the caise.messaging architecture, illustrated examples of caise.messaging-based tools, and Api details.

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  • An Extensible Framework for Collaborative Software Engineering

    Cook, Carl; Churcher, Neville (2003)

    Doctoral thesis
    University of Canterbury Library

    The size, complexity and duration of typical software engineering projects means that teams of developers will work on them. However, with the exception of version control systems, the editors, diagrammers and other tools used will generally support only a single user. In this paper, we present an architecture for bringing to software engineering development environments the advantages of awareness of the presence, and the intentions and actions of others. Thus far, the applications of such facilities have been primarily in simple Computer Supported Collaborative Work (CSCW) tools, such as shared whiteboards, where the corresponding artifacts, unlike those of software engineering, are typically both simple and transient. We describe our implementation of the architecture and prototype tools and illustrate the benefits of providing support for real-time collaboration between developers located anywhere on the Internet. We also describe how our architecture, which is based on a parse tree representation of artifacts, may be extended readily to include new tools, languages, and notations or be customised to provide new awareness mechanisms.

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  • Inherited retinal degenerations

    Fletcher, EL; Acosta, Monica L; Kalloniatis, Michael (2009)

    Book item
    The University of Auckland Library

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  • Is there a temporal pattern in the occurrence of subarachnoid hemorrhage in the Southern Hemisphere? Pooled data From 3 large, population-based incidence studies in Australasia, 1981 to 1997

    Feigin, V; Anderson, CS; Anderson, NA; Broad, Joanna; Pledger, M; Bonita, R (2001)

    Journal article
    The University of Auckland Library

    Background and Purpose???Publications on the temporal pattern of the occurrence of subarachnoid hemorrhage (SAH) have produced conflicting results. Variations between studies may relate to the relatively small numbers of SAH cases analyzed, including those in meta-analyses. Methods???We identified all cases of SAH from 3 well-designed population-based studies in Australia (Adelaide, Hobart, and Perth) and New Zealand (Auckland) during 3 periods between 1981 and 1997. The diagnosis of SAH was confirmed with CT, cerebral angiography, cerebrospinal fluid analysis, or autopsy in all cases. Information on the time of occurrence of each event was obtained. Risk ratios (RRs) and 95% CIs were calculated using Poisson regression, with age, sex, smoking status, and history of hypertension entered in the model as covariates. Results???A total of 783 cases of SAH were registered. Age- and sex-adjusted RRs of SAH occurrence were highest in the period between 6 AM and 12 MIDNIGHT (RR 3.2, 95% CI 2.4???4.3) and in winter and spring (RR 1.3, 95% CI 1.1???1.5; RR 1.3, 95% CI 1.1???1.5; respectively). No particular pattern of SAH occurrence was observed according to the day of the week. Restriction of the analyses to proved aneurysmal SAH did not substantially change the point estimates. Conclusions???Circadian and circaseptan (weekly) fluctuations of SAH occurrence in the southern hemisphere are similar to those in the northern hemisphere, but the occurrence of SAH in Australasia exhibits clear seasonal (winter and spring) peaks.

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  • Creatine transporter localization in developing and adult retina: Importance of creatine to retinal function

    Acosta Etchebarne, Monica; Kalloniatis, Michael; Christie, David (2005-09-12)

    Journal article
    The University of Auckland Library

    Creatine and phosphocreatine are required to maintain ATP needed for normal retinal function and development. The aim of the present study was to determine the distribution of the creatine transporter (CRT) to gain insight to how creatine is transported into the retina. An affinity-purified antibody raised against the CRT was applied to adult vertebrate retinas and to mouse retina during development. Confocal microscopy was used to identify the localization pattern as well as co-localization patterns with a range of retinal neurochemical markers. Strong labeling of the CRT was seen in the photoreceptor inner segments in all species studied and labeling of a variety of inner neuronal cells (amacrine, bipolar, and ganglion cells), the retinal nerve fibers and sites of creatine transport into the retina (retinal pigment epithelium, inner retinal blood vessels, and perivascular astrocytes). The CRT was not expressed in M??ller cells of any of the species studied. The lack of labeling of M??ller cells suggests that neurons are independent of this glial cell in accumulating creatine. During mouse retinal development, expression of the CRT progressively increased throughout the retina until approximately postnatal day 10, with a subsequent decrease. Comparison of the distribution patterns of the CRT in vascular and avascular vertebrate retinas and studies of the mouse retina during development indicate that creatine and phosphocreatine are important for ATP homeostasis.

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  • Early markers of retinal degeneration in rd/rd mice

    Acosta Etchebarne, Monica; Fletcher, EL; Azizoglu, Serap; Foster, LE; Farber, DB; Kalloniatis, Michael (2005-09-06)

    Journal article
    The University of Auckland Library

    PURPOSE: In the rd/rd mouse, the cell death of rod photoreceptors has been correlated to abnormal levels of the cyclic nucleotide cGMP within photoreceptors. Given that cGMP is required for opening of the cationic channels, there is the possibility that a high cGMP concentration would maintain these channels open, at a high energy cost for the retina. METHODS: We investigated whether cation channels were maintained in an open state in the rd/rd mouse retina by determining the labeling pattern of an organic cationic probe (agmatine, AGB) which selectively enters cells through open cationic channels. The metabolic activity of the rd/rd mice was measured by assaying lactate dehydrogenase (LDH) activity in several tissues and Na+/K+ ATPase activity was measured as a function of development and degeneration of the retina. RESULTS: AGB neuronal labeling showed a systematic increase consistent with the known neuronal functional maturation in the normal retina. There was a significant higher AGB labeling of photoreceptors in the rd/rd mouse retina from P6 supporting the possibility of open cationic channels from an early age. There were no changes in the LDH activity of tissues that contain PDE6 or that have a similar LDH distribution as the retina. However, LDH activity was significantly higher in the rd/rd mouse retina than in those of control mice from birth to P6, and it dramatically decreased from P9 as the photoreceptors degenerated. The predominant LDH isoenzyme changes and loss after degeneration appeared to be LDH5. ATPase activity increased with age, reaching adult levels by P16. Unlike LDH activity, there was no significant difference in Na+/K+ ATPase activity between control and rd/rd mice at any age examined. CONCLUSIONS: We conclude that AGB is a useful marker of photoreceptors destined to degenerate. We discard the possibility of a generalized metabolic effect in the rd/rd mice. However, the elevated LDH activity present before photoreceptor differentiation indicated altered retinal metabolic activity that could not be associated with open cationic channels alone. Therefore, altered metabolic activity as indicated by LDH measurements in the retina appeared to be the earliest sensitive sign of future photoreceptor dysfunction in the rd/rd mice.

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  • Reduced Complexity Decoding of Space Time Trellis Codes in the Frequency Selective Channel

    Turner, Jeremy (2005)

    Doctoral thesis
    University of Canterbury Library

    In this work a new iterative approach has been suggested for decoding Space Time Trellis Codes (STTCs) in the frequency selective Multiple Input Multiple Output (MIMO) channel. The objective of this thesis has been to investigate the performance of the approach and determine what parameters affect its performance. The proposed method uses the Partitioned Viterbi Algorithm (PVA) as an equalizer for the MIMO system. The equaliser provides soft outputs which are then used by a STTC decoder to estimate the transmitted data sequence. To reduce error propagation between the two Viterbi based algorithms, an interleaver is introduced. To further increase the performance, an iterative approach is used, where the decoded data sequence is re-encoded and used by the PVA to improve interference cancellation. This is similar in concept to turbo equalisation. Both the PVA equaliser and STTC decoder have been adapted to provide soft outputs using a Soft Output Viterbi Algorithm (SOVA). Simulations of a NT = 2 transmit antenna, NR = 2 receive antenna MIMO system have been performed for both 4PSK and 8PSK constellations. It is shown that the iterative procedure achieves a performance within 2.0dB of Maximum Likelihood (ML) decoding, at a FER of 10-2. However, the iterative approach suffers a small diversity loss. It is also shown that the complexity of the iterative approach is far lower than ML decoding. For example, a 16 state 4PSK STTC can be decoded using the iterative approach, with equal performance and less complexity, than a 4 state 4PSK with ML decoding. It is also shown that for a large diversity system (rNR>3), where is the rank of the STTC, that codes designed using the trace, or Euclidean distance criteria, suggested by Chen et.al. [10] are superior to the rank and determinant criteria used by Tarokh et.al. [59] and Baro et.al. [6]. Other factors investigated that affect the performance are the choice of interleaver, number of iterations, soft information and the size of the MIMO system. The use of a PVA or similar equaliser, coupled with an outer code could be used to increase the effective user bandwidth of the MIMO channel. Standard convolutional codes could be used with the equaliser to improve performance in an iterative approach. More research is required to investigate the performance and complexity of such an approach.

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  • University of Canterbury Technical Report: Approximating the Probability Distribution of OFDM Symbol Errors

    Clark, Alan; Smith, Peter; Taylor, Desmond (2005)

    Doctoral thesis
    University of Canterbury Library

    Given an N subcarrier orthogonal frequency division multiplexing (OFDM) system transmitting over a slow fading Rayleigh channel, the distribution of b, the exact number of received symbol errors, is Poisson binomial. Hence, N!/(N-b)!/b!, terms are required to calculate each probability for b=0,1,...,N. When N is large, as in most OFDM systems, the Poisson binomial distribution is often approximated by the Poisson distribution. We show that, for large N, the total variation distance between the approximation and the true distribution is lower and upper bounded by random variables with fully known probability density functions. The bounds on the total variation distance indicate that the distribution of OFDM symbol errors is well approximated by a Poisson distribution.

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  • Lattice Codes and Generalized Minimum Distance Decoding for OFDM Systems

    Clark, Alan; Taylor, Desmond P. (2005)

    Doctoral thesis
    University of Canterbury Library

    Lattice coding of orthogonal frequency division multiplexing (OFDM) systems is considered. Mapping of multilevel construction lattices to OFDM blocks is shown, and a methodology for probabilistic analysis of multistage generalized minimum distance (GMD) decoding of the received OFDM blocks is derived. As a case study transmission of points from a 128-dimensional Barnes-Wall lattice is considered. Tight approximations to the system error rate are obtained and verified by simulation. It appears that GMD decoding of lattice encoded OFDM provides high coding gain at low complexity.

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  • ON AUTOMATED SEQUENTIAL STEADY-STATE SIMULATION

    Lee, Jong-Suk Ruth (2000)

    Doctoral thesis
    University of Canterbury Library

    The credibility of the final results from stochastic simulation has had limited discussion in the simulation literature so far. However, it is important that the final results from any simulations be credible. To achieve this, validation, which determines whether the conceptual simulation model is an accurate representation of the system under study, has to be done carefully. Additionally, a proper statistical analysis of simulation output data, including a confidence interval or other assessment of statistical errors, has to be conducted before any valid inferences or conclusions about the performance of simulated dynamic systems, such as for example telecommunication networks, are made. There are many other issues, such as choice of a good pseudo-random number generator, elimination of initialisation bias in steady-state simulations, and consideration of autocorrelations in collected observations, which have to be appropriately addressed for the final results to be credible. However, many of these issues are not trivial, particularly for simulation users who may not be experts in these areas. As a consequence, a fully-automated simulation package, which can control all important aspects of stochastic simulation, is needed. This dissertation focuses on the following contributions to such a package for steady-state simulation: properties of confidence intervals (CIs) used in coverage analysis, heuristic rules for improving the coverage of the final CIs in practical applications, automated sequential analysis of mean values by the method of regener- ABSTRACT ative cycles, automatic detection of the initial transient period for steady-state quantile estimation, and sequential steady-state quantile estimation with the automated detection of the length of initial transient period. One difficulty in obtaining precise estimates of a system using stochastic simulation can be the cost of the computing time needed to collect the large amount of output data required. Indeed there are situations, such as estimation of rare events, where, even assuming an appropriate statistical analysis procedure is available, the cost of collecting the number of observations needed by the analysis procedure can be prohibitively large. Fortunately, inexpensive computer network resources enable computationally intensive simulations by allowing us to run parallel and distributed simulations. Therefore, where possible, we extend the contributions to the distributed stochastic simulation scenario known as the Multiple Replications In Parallel (MRIP), in which multiple processors run their own independent replications of the simulated system but cooperate with central analysers that collect data to estimate the final results.

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  • An O(n 3 log log n/ log n) Time Algorithm for the All-Pairs Shortest Path Problem

    Takaoka, Tadao (2004)

    Doctoral thesis
    University of Canterbury Library

    We design a faster algorithm for the all-pairs shortest path problem under the conventional RAM model, based on distance matrix multiplication (DMM). Specifically we improve the best known time complexity of O(n 3 (log log n) 2/ log n) to O(n 3 log log n/ log n). As an application, we show the k-maximum subarray problem can be solved in O(kn 3 log log n/ log n) time for small k.

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  • An O(n 3 log log n/ log2 n) Time Algorithm for All Pairs Shortest Paths

    Han, Yijie; Takaoka, Tadao (2002)

    Doctoral thesis
    University of Canterbury Library

    Given an input directed graph G = (V, E), the all pairs shortest path problem (APSP) is to compute the shortest paths between all pairs of vertices of G assuming that edge costs are real values. The APSP problem is a fundamental problem in computer science and has received considerable attention. Early algorithms such as Floyd’s algorithm ([2], pp. 211-212) computes all pairs shortest paths in O(n 3 ) time, where n is the number of vertices of the graph. Improved results show that all pairs shortest paths can be computed in O(mn+n 2 log n) time [9], where m is the number of edges of the graph. Pettie showed [14] an algorithm with time complexity O(mn+n 2 log log n). See [15] for recent development. There are also results for all pairs shortest paths for graphs with integer weights[10, 16, 17, 21– 23]. Fredman gave the first subcubic algorithm [8] for all pairs shortest paths. His algorithm runs in O(n 3 (log log n/ log n) 1/3 ) time. Fredman’s algorithm can also run in O(n 2.5 ) time nonuniformly. Later Takaoka improved the upper bound for all pairs shortest paths to O(n 3 (log log n/ log n) 1/2 ) [19]. Dobosiewicz [7] gave an upper bound of O(n 3/(log n) 1/2 ) with extended operations such as normalization capability of floating point numbers in O(1) time. Earlier Han obtained an algorithm with time complexity O(n 3 (log log n/ log n) 5/7 ) [12]. Later Takaoka obtained an algorithm with time O(n 3 log log n/ log n) [20] and Zwick gave an algorithm with time O(n 3√ log log n/ log n) [24]. Chan gave an algorithm with time complexity of O(n 3/ log n) [6]. Chan’s algorithm does not use tabulation and bit-wise parallelism. His algorithm also runs on a pointer machine.

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  • Matrix Multiplication and All Pairs Shortest Paths

    Takaoka, Tadao (2002)

    Doctoral thesis
    University of Canterbury Library

    The all pairs shortest path (APSP) problem is to compute shortest paths between all pairs of vertices of a directed graph with non-negative real numbers as edge costs. We focus on shortest distances between veritices, as shortest paths can be obtained with a slight increase of cost. Classically the APSP problem can be solved in cubic time of O(n 3 ). The problem here is to achieve a sub-cubic time for a graph with small integer costs. A directed graph is given by G = (V, E), where V = {1, · · · , n}, the set of vertices, and E is the set of edges. The cost of edge (i, j) ∈ E is denoted by dij. The (n, n)-matrix D is one whose (i, j) element is dij. We assume that dij ≥ 0 and dii = 0 for all i, j. If there is no edge from i to j, we let dij = ∞. The cost, or distance, of a path is the sum of costs of the edges in the path. The length of a path is the number of edges in the path. The shortest distance from vertex i to vertex j is the minimum cost over all paths from i to j, denoted by d ∗ ij. Let D∗ = {d ∗ ij}. We call n the size of the matrices. Let A and B are (n, n)-matrices. The three products are defined using the elements of A and B as follows: (1) Ordinary matrix product over a ring C = AB, (2) Boolean matrix product C = A · B, and (3) Distance matrix product C = A × B, where (1) cij = Xn k=1 aikbkj , (2) cij = _n k=1 aik ∧ bkj , (3) cij = min 1≤k≤n {aik + bkj}. The matrix C is called a product in each case; the computational process is called multiplication, such as distance matrix multiplication. In those three cases, k changes through the entire set {1, ..., n}. We define a partial matrix product of A and B by taking k in a subset I of V . In other words, a partial product is obtained by multiplying a vertically rectangular matrix, A(∗, I), whose columns are extracted from A corresponding to the set I, and similarly a horizontally rectangular matrix, B(I, ∗), extracted from B with rows corresponding to I. Intuitively I is the set of check points k, when we go from i to j. The best algorithm [3] computes (1) in O(n ω ) time, where ω = 2.376. We carry three decimal points. To compute (2), we can regard Boolean values 0 and 1 in A and B as integers

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  • MDRIP: A Hybrid Approach to Parallelisation of Discrete Event Simulation

    Chao, Daphne (2005)

    Doctoral thesis
    University of Canterbury Library

    The research project reported in this thesis considers Multiple Distributed Replications in Parallel (MDRIP), a hybrid approach to parallelisation of quantitative stochastic discrete-event simulation. Parallel Discrete-Event Simulation (PDES) generally covers distributed simulation or simulation with replicated trials. Distributed simulation requires model partitioning and synchronisation among submodels. Simulation with replicated trials can be executed on-line by applying Multiple Replications in Parallel (MRIP). MDRIP has been proposed for overcoming problems related to the large size of simulated models and their complexity, as well as with the problem of controlling the accuracy of the final simulation results. A survey of PDES investigates several primary issues which are directly related to the parallelisation of DES. A secondary issue related to implementation efficiency is also covered. Statistical analysis as a supporting issue is described. The AKAROA2 package is an implementation of making such supporting issue effortless. Existing solutions proposed for PDES have exclusively focused on collecting of output data during simulation and conducting analysis of these data when simulation is finished. Such off-line statistical analysis of output data offers no control of statistical errors of the final estimates. On-line control of statistical errors during simulation has been successfully implemented in

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