Experimental Evaluation of A Parallel Spectral Method for Run Length Control in Steady-State Simulation

. Distributed and parallel simulation has been a popular research topic in recent years. The research has primarily concentrated on correctness and speedup of distributed simulation. The statistical output analysis that is an essential part of simulating stochastic systems has attained only small attention. Parallel simulation is often mentioned as an attractive alternative for steady-state simulations. However, empirical results are not widely reported. We describe an implementation of an method that combines independent simultaneous replications and the spectral method. We also present experimental results are based on 12 simulation models executed in a network of Sun SPARCstations. CR Categories and Subject Descriptors: I.6.6 [Simulation and Modeling]: Simulation Output Analysis --- sequential estimation. I.6.8 [Simulation and Modeling]: Types of Simulation --- parallel. General Terms: Algorithms, Experimentation, Performance. Additional Key Words and Phrases: Parallel simulation..

Simulation Estimation of Dynamic Properties in Queueing Systems

In simulation studies the focus has traditionally been on time-independent characteristics of queueing systems, particularly on the steady-state mean. The systems, even if they are in stochastic equilibrium, have also timedependent or dynamic properties which are of great practical importance. Typically, the dynamic properties are related to the variation of traffic or load during some period of time. In this paper we propose a way to examine dynamic properties of queueing systems through simulation. Our approach is based on the following idea: The original traffic rates are classified into low and heavy values. The resulting binary sequence of indicators characterize the traffic level of the system. The variation in the traffic level is summarized through estimating the two histograms of level durations. The rationale of translating the problem into simultaneous estimation of two histograms is that the estimates for the cell proportions are based on cumulative statistics. Therefore, w..

Information Aspects of Services and Service Features in Intelligent Network Capability Set 1

. The concept of Intelligent Networks as specified in the current ITU-T Recommendations in Q.1200 Series presents a way of applying information processing technology in order to provide telecommunication services. The world-wide nature of telecommunication services requires that the systems are open distributed systems. We examined the services and service features described in ITU-T Capability Set 1 from the ODP information viewpoint. Key Words: Telecommunication, Intelligent Networks, Open Distributed Processing, Information Viewpoint. CR Classification: C.2.4, H.4.3, J.7 y This report is based on work done for Darfin-project (Project No 30018) funded by Telecom Finland. Information Aspects of Services and Service Features in IN CS-1 Contents 1 Introduction 1 2 Information Model for Telecommunication Services 2 3 Targeted Services 3 3.1 Abbreviated dialling (ABD) : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 3 3.2 Account card calling (ACC) : : : : : : : : :..

Symptoms of Self-Similarity in Measured Arrival Process of Ethernet Packets to A File Server

this paper we report our measurement study of the arrival process of Ethernet packets into a file server. Our primary finding is that the measured index of dispersion for counts does not provide reliable evidence for or against self-similarity. This conclusion is also supported by extensive simulations. ( Traffic measurements; Arrival process; Fractal Brownian motion; Markov modulated Poisson process; Model identification ) 1. Introductio

Run Length Control For Simultaneous Estimation Of Several Percentiles In Dependent Sequences

: Percentiles are convenient indices to describe simulation output data. A few percentiles are more informative than the mean and the standard deviation. However, percentiles are very seldom used in practice. The reason has been that percentile estimation is regarded as a cumbersome task. All previously reported methods estimate only a single percentile. In addition, they have been methods of fixed, predefined, run length. The method introduced in this paper does not have these limitations. It estimates several percentiles simultaneously without storing and sorting the output sequence. It also has a run length control mechanism, which terminates the simulation run, when the estimates are accurate enough. The relative half-width criterion, which is commonly used to control the accuracy of the simulated mean, is generalized to control the accuracy of multidimensional estimates. The proposed method dynamically approximates the inverse of the empirical cumulative distribution function by a..

Controlling The Precision Of Estimated Means In Interactive Simulation

The computing power of modern workstations has made it possible to simulate many queueing systems interactively. Recent development in simulation software has mainly concentrated on interactive facilities. Unfortunately the precision of estimates has widely been overlooked in interactive simulation. In this paper we propose a method for controlling the precisions of estimated means during an interactive simulation run. Since in a typical situation of interactive simulation the user is simultaneously interested in several means, we consider both the simultaneous precision and individual precisions of the estimated means. The method is based on the existing methods for estimating standard errors and on the Bonferroni inequality. The Bonferroni inequality is used to obtain a lower bound for the simultaneous precision. Key Words: Confidence estimation, Graphical user interface, Interactive simulation, Queueing network simulation, Run-length control, Sequential estimation, Simultaneous infe..

Approximating Response Time Distributions

: The response time is the most visible performance index to users of computer systems. End-users see individual response times, not the average. Therefore the distribution of response times is important in performance evaluation and capacity planning studies. However, the analytic results cannot be obtained in practical cases. A new method is proposed to approximate the response-time distribution. Unlike the previous methods the proposed one takes into account the service-time distributions and routing behaviour. The reported results indicate that the method provides reasonable approximations in many cases. 1 Introduction Queueing network modelling is a popular tool in the performance evaluation of computer systems. It has been successfully used in various applications of modelling computer systems. In most applications only the mean values of performance indices, such as mean device queue-lengths and the mean system response-time, have been considered. The increasing usage of comput..