scispace - formally typeset
Search or ask a question

Showing papers on "Network traffic simulation published in 1985"



Journal Article
TL;DR: Moving traffic interference, which is represented by stochastic short-term lane blockages of varying duration and frequency, is shown to be a key determinant of the traffic character of an urban street network and of the behavior described by the two-fluid theory and verified operationally.
Abstract: Presented in this paper is a systematic exploration, using microscopic simulation, of the sensitivity of network-level traffic flow descriptors and relationships, particularly those of the two-fluid theory of town traffic, to network features, traffic control, and traffic-interfering urban activity levels. Moving traffic interference, which is represented by stochastic short-term lane blockages of varying duration and frequency, is shown to be a key determinant of the traffic character of an urban street network and of the behavior described by the two-fluid theory and verified operationally. In addition, the sensitivity of the two-fluid model parameters to a change in traffic control strategy, in this case the coordination of signals to achieve progression, is demonstrated. Furthermore, keeping the same network configuration, the effect of network topology on traffic flow is examined by changing the identical length of the links.

40 citations


Journal ArticleDOI
L. T. Wu1
01 Sep 1985
TL;DR: This paper analyzed one class of nonuniform traffic pattern referred to as “point-to-point” traffic that has particular significance to mixed voice, data, and video applications and found that even a single dedicated channel can significantly limit the throughput of the background uniform traffic.
Abstract: A model of Banyan networks is developed to account for their operational as well as topological characteristics. The model incorporates a description of the states of individual switching nodes and explicitly captures the interconnection patterns between stages. Accordingly, the performance of a network can be evaluated via an iterative procedure. Using the model, we analyzed one class of nonuniform traffic pattern referred to as “point-to-point” traffic that has particular significance to mixed voice, data, and video applications. The results obtained indicate that even a single dedicated channel (with point-to-point traffic) can significantly limit the throughput of the background uniform traffic. The paper concludes with several switch design strategies for switching point-to-point traffic using a self-routing switching network.

37 citations



Journal ArticleDOI
TL;DR: The performance (using analytical and simulation models) of a class of highly reliable double loop network architectures is presented, and the richer topology of double loop networks allows more sophisticated routing algorithms to be used.
Abstract: Single loop networks tend to become unreliable and suffer from poor performance when the number of nodes in the network becomes large. One approach to increasing reliability and improving performance is to use a double loop. In this paper, the performance (using analytical and simulation models) of a class of highly reliable double loop network architectures is presented. The richer topology of double loop networks allows more sophisticated routing algorithms to be used. Several routing algorithms are studied, including: fixed, adaptive to failure, and fully adaptive to failure and traffic load conditions.

25 citations


Proceedings ArticleDOI
15 Dec 1985
TL;DR: The binary tree and its X-tree variant are found to be especially attractive network configurations in simulation applications with simulation tasks assigned to nodes according to a model-frame/experiment- frame/output-frame trichotomy.
Abstract: Statistical considerations in simulating complex systems on a hierarchical network of low-cost microcomputers are discussed. Network configurations, allocation of computer tasks to nodes of the network, and assignment of simulation trials are examined. The binary tree and its X-tree variant are found to be especially attractive network configurations in simulation applications with simulation tasks assigned to nodes according to a model-frame/experiment-frame/output-frame trichotomy. Procedures for performing designed simulation experiments, including factor screening experiments, and for conducting variance reduction through manipulation of random number streams are presented.

23 citations


Proceedings ArticleDOI
01 Mar 1985
TL;DR: Three performance studies based on a prototype implementation of one parallel simulation algorithm are presented, examining the implementation's efficiency, the kind and amount of overhead for simulated events, and the feasibility of implementing the Chandy-Misra algorithm on a multiprocessor.
Abstract: Although evaluating a detailed discrete event simulation model of a large scale system can be computationally taxing, parallel simulation provides hope of reducing computation time to tractable levels. We present three performance studies based on a prototype implementation of one parallel simulation algorithm. The first examines the implementation's efficiency, the kind and amount of overhead for simulated events. The second study presents the results of an attempted vectorization of the prototype on a commercial vector processor. The final study reports the feasibility of implementing the Chandy-Misra algorithm on a multiprocessor.

16 citations


Journal Article
TL;DR: A stochastic discrete-event simulation model system for heterogeneous road traffic, which prevails on the Indian highway network, is presented and should be useful to decision makers for obtaining reliable data for investment analysis.
Abstract: A stochastic discrete-event simulation model system for heterogeneous road traffic, which prevails on the Indian highway network, is presented. The original Swedish Road Traffic Simulation Model system, designed for motorized traffic, has been generalized to cover heterogeneous traffic that includes slowmoving nonmotorized traffic. The model has also been extended for narrow roads and covers roadwidths from 3.75 to 13 m with different shoulder types and alignments in flat, rolling, and hilly terrains. Submodels for the basic desired speed, power-to-mass ratio, overtaking gap acceptance and yielding probability distributions, passing speeds, and fuel consumption rates have been calibrated with extensive field data for subsequent validation of the simulation model. The output of the model has been intended primarily (a) to furnish relevant vehicle operating data for appraisal of individual road projects, (b) to constitute background data for a relevant level of service concept, and (c) ultimately to provide a basis for an appropriate policy on geometric design of rural roads in general. The model has been programmed in SIMULA-67 language using Jackson Structured Programming concepts. The results of validation exercises have been convincing; the model should be useful to decision makers for obtaining reliable data for investment analysis.

12 citations


Proceedings ArticleDOI
15 Dec 1985
TL;DR: This study attempts to show that there are benefits of coordination for some combinations of side street turning traffic and how to obtain the optimal offsets from the simulation model.
Abstract: The traffic delay and signal timing offset of adjacent signalized intersections are studied by stochastic computer simulation. The emphasis is on the effect of turning movements on traffic signal coordination. Coordination synchronizes the flow of traffic through a sequence of signals in order to minimize delays and stops. It's application is traditionally restricted to major thoroughfares where turning movements from side streets are insignificant. This study attempts to show that there are benefits of coordination for some combinations of side street turning traffic and how to obtain the optimal offsets from the simulation model.

8 citations


01 Nov 1985
TL;DR: In this paper, the application of the diagonalization algorithm to solve a two-class network equilibrium problem with asymmetric link interactions was examined, and the main aspects of the algorithm's performance examined in this study are its convergence characteristics as well as the effectiveness of some streamlining strategies aimed at improving its computational performance.
Abstract: This report examines the application of the diagonalization algorithm to solve a two-class network equilibrium problem with asymmetric link interactions. The two classes that the traffic stream was divided into are passenger cars and trucks. Both traffic assignment rules, the User Equilibrium and System Optimum have been tested on three different networks. The third test network is a representation of the Texas highway network, thus providing a realistic case application. An important feature developed and implemented in this study is a special structure of the network, where every link was coded in a way to account for exclusive lanes of either category of vehicles as well as common lanes for all traffic. This structure provides a tool to evaluate the performance of a network under different types of improvements involving the separation of the different categories of vehicles in the traffic stream. The main aspects of the algorithm's performance examined in this study are its convergence characteristics as well as the effectiveness of some streamlining strategies aimed at improving its computational performance. Although convergence is not guaranteed, it was actually achieved in all the tests conducted, confirming the algorithm's appropriateness for this type of application. Furthermore, experience gained from the tests has identified powerful and relatively simple shortcuts for implementing the algorithm. Further research needed for implementation purposes is also discussed (A).

4 citations


Proceedings ArticleDOI
15 Dec 1985
TL;DR: This research addressed the performance characteristics of a computer-communication network that integrates both voice and data traffic on the backbone of the network using an event-driven FORTRAN simulation model based on a circuit-switched communications subnet.
Abstract: This research addressed the performance characteristics of a computer-communication network that integrates both voice and data traffic on the backbone of the network. Network performance was analyzed using an event-driven FORTRAN simulation model. The model was based on a circuit-switched communications subnet whose trunk lines carry both voice and data traffic simultaneously. A sizing and timing analysis is accomplished by collecting empirical performance data for a variety of system input parameter combinations. The data was analyzed to determine simulation running time needed to reach steady state and to size the input parameter ranges that correspond to feasible network performance.

01 Jan 1985
TL;DR: A generalized queueing model simulation of store-and-forward computer communication networks is developed and implemented using Simulation Language for Alternative Modeling (SLAM) and validated by comparison with published analytic models.
Abstract: A generalized queueing model simulation of store-and-forward computer communication networks is developed and implemented using Simulation Language for Alternative Modeling (SLAM). A baseline simulation model is validated by comparison with published analytic models. The baseline model is expanded to include an ACK/NAK data link protocol, four-level message precedence, finite queues and a response traffic scenario. Network performance, as indicated by average message delay and message throughput, is estimated using the simulation model.