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Simulation Conference, 1991. Proceedings., Winter

Date 8-11 Dec. 1991

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  • 1991 Winter Simulation Conference Proceedings (Cat. No.91CH3050-2)

    Publication Year: 1991
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    Freely Available from IEEE
  • Interactive experiment planning to control knowledge-based simulation

    Publication Year: 1991 , Page(s): 1218 - 1227
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    The author presents an initial attempt to facilitate the design and execution of simulation experiments through the use of an interactive, opportunistic, hierarchical planner. The planner provides an orderly way to control the planning and execution of simulation experiments without overly restricting the user to a preestablished routine. In addition to planning the simulation and keeping track of its current state, the planner, through its graphical interface, can provide the simulator with a natural, coherent framework for its user interface. Examples are presented of the planner's graphical interface View full abstract»

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  • An axiomatic basis for general discrete-event modeling

    Publication Year: 1991 , Page(s): 1073 - 1082
    Cited by:  Papers (2)
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    The author proposes DMOD, a novel formulation of the discrete-event technique (DET). It enables the user to directly specify the causality relation between events. Thereby, model building is greatly simplified. DMOD also defines event occurrences in a logical manner, which makes it possible to build a framework for formulating and proving temporal properties. An implementation of both DMOD models and the reasoning framework is shown using the logic of definite clauses View full abstract»

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  • A framework for simulation design of flexible manufacturing systems

    Publication Year: 1991 , Page(s): 1106 - 1114
    Cited by:  Papers (1)
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    A framework is being developed for simulation-based design of flexible manufacturing systems. The framework integrates generation of assembly plans, design and configuration of the manufacturing facility and equipment, synthesis of task-oriented robot programs, and simulation of a manufacturing system. Each layer is briefly summarized, and a simulation case study of a system for electric motor assembly is presented View full abstract»

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  • Effective application of simulation in the life cycle of a manufacturing cell project

    Publication Year: 1991 , Page(s): 411 - 418
    Cited by:  Papers (1)
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    In a simulation of an automated floor panel fabrication cell (Boeing's Automated Floor Panel Workcell), it was shown how simulation can be used successfully throughout the system development life cycle. The authors present the role simulation played throughout the system life cycle, with special emphasis on fine-tuning cell operations and cell controller scheduling algorithms. With simulation, numerous options were tested without incurring large capital costs or disrupting operations. Simulation provided an excellent vehicle for reducing risks associated with implementation of a very complex costly system because it provided excellent overall system visibility, was effective in communicating concepts and designs, reduced design and development time, and significantly improved the quality of designs View full abstract»

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  • Simulation languages and database theory: some considerations from the entity-relationship model

    Publication Year: 1991 , Page(s): 1228 - 1235
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    Entity-relationship (ER) database modeling techniques are applied to discrete event simulation. The ER model provides a logical way to organize the data from a simulation run. When the output data are stored using this organization, a relational database can be used to make queries in a database language that should answer virtually any question about the simulation performance and facilitate the statistical analysis of the data. The ER modeling approach is contrasted with the models which are used in the simulation language SIMAN. This comparison provides insight into both approaches and suggests some modifications and additions to the SIMAN language which should improve its flexibility and make it more consistent with the ER theory View full abstract»

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  • Simultaneous parallel simulations of continuous time Markov chains at multiple parameter settings

    Publication Year: 1991 , Page(s): 602 - 607
    Cited by:  Papers (3)
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    The authors describe multi-PUCS (parallel uniformized continuous-time simulation), an approach based on uniformization for simultaneously running parallel simulation of CTMCs (continuous time Markov chains) at multiple parameter settings. In multi-PUCS, interprocessor communications messages are shared among the multiple simulations. The efficiency of multi-PUCS relative to another multiple parameter simulation approach, the consecutive strategy, was studied empirically through simulations of a large queuing network on a 16-node Intel iPSC/2. Generally speaking, if the parameter being varied is such that the external uniformization rates are unaffected, then multi-PUCS becomes (relatively) more efficient as the amount of interprocessor communications increases. However, the efficiency gains over the consecutive strategy were fairly modest when combining two parameter settings. Better performance can be achieved when more parameter settings are included. In addition, moderate positive correlation was induced using this approach View full abstract»

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  • Measuring the user acceptance of generic manufacturing simulation models by review of modeling assumptions

    Publication Year: 1991 , Page(s): 419 - 427
    Cited by:  Papers (2)
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    A measure of user acceptance for generic discrete manufacturing models is introduced. This measure is based on review of modeling assumptions and computed as the percentage of assumptions that are acceptable to the user. The assumptions, which describe the modeling options that are available in generic models, give the user a detailed account of the capabilities and limitations of the generic models. The assumption review process and the user acceptance measure are implemented within the framework of an intelligent simulation environment. GUIDES, an expert system, guides the user through the review of assumptions and generates the user acceptance scores. It is concluded that, although certain modifications can be made in the generic models to eliminate some of the rejections concerning the assumptions, the model acceptance, in general, is fairly high (91.78%) View full abstract»

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  • An efficient and scalable parallel algorithm for discrete-event simulation

    Publication Year: 1991 , Page(s): 652 - 658
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    The authors describe a novel parallel algorithm for discrete-event simulation on an exclusive-read exclusive-write parallel random-access machine (EREW PRAM). This algorithm is based on a recently developed parallel data structure, namely the parallel heap, which, when used as a parallel event-queue, allows deletion of O(p) earliest messages and insertion of O(p) new messages each in O(log n) time, using p processors, where n is the number of messages scheduled. The proposed algorithm can simulate up to p independent messages in O(log n) time, thus achieving O(p ) speedup. The number of processors, p, can be optimally varied in the range 1⩽pn View full abstract»

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  • When is a satellite not a toaster? [satellite repair costs]

    Publication Year: 1991 , Page(s): 499 - 508
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    It is pointed out that automobiles are typically repaired, but inexpensive appliances are discarded at the first sign of trouble: they `cost too much to fix.' Comparing $50 M satellites with toasters may seem odd, but the analogy can be appropriate. It is suggested that the too-much-to-fix argument can be used in deciding whether to replace or to repair satellites. The authors investigate when cost considerations dictate using constellations of expendable satellites to be routinely replaced and discarded on failure, and when circumstances indicate using constellations of satellites to be repaired on-orbit by exchanging failed modules View full abstract»

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  • The robustness of separable queueing network models

    Publication Year: 1991 , Page(s): 661 - 668
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    Discrete event simulation is used to explore the robustness of queuing network models, a set of powerful analytical techniques for evaluating computer system performance. These techniques are shown to give good results even when some of the basic assumptions used to derive them are violated. It is also shown that simulation provides additional insights into computer system performance which are not available when using the mean value analysis characteristic of separable queuing network approaches View full abstract»

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  • Object oriented simulation tools necessary for a flexible batch process management architecture

    Publication Year: 1991 , Page(s): 323 - 330
    Cited by:  Patents (2)
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    Present an architecture for batch process management with particular emphasis on the simulation tools contained in the environment. Within the architecture are a suite of high-level tools that interface with a user to obtain a high level of batch processing flexibility. These high-level tools are being developed in a modular fashion. Two simulation assistants have been proposed for a complete batch process management architecture. These include a batch sequencing simulation assistant and a control specification simulation assistant. It is felt that these tools will significantly increase the batch process management life-cycle time and increase process plant flexibility View full abstract»

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  • Simulation of Fox River locks boat lift

    Publication Year: 1991 , Page(s): 802 - 808
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    The SLAM computer simulation model of the locks system on the lower Fox River was modified to represent the operation of a proposed boat lift at the Rapide Croche lock. This boat lift is needed due to construction of a barrier to prevent migration of sea lamprey into the Fox River and Wolf River basins. The barrier gas put in place prior to the 1988 navigation season by sealing the Rapide Croche lock. Since then only three end locks have been operated. Prior to the sea lamprey barrier, the entire system of sixteen locks had been operated every summer since 1856. Two alternatives have been proposed for the boat lift at Rapide Croche. The simulation model was used to investigate delay of boat traffic within the system for both alternatives View full abstract»

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  • A method for generating random cutting-tool requirement matrices for manufacturing systems simulation

    Publication Year: 1991 , Page(s): 854 - 860
    Cited by:  Papers (1)
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    The authors describe a two-stage procedure for generating random cutting-tool requirement matrices (part type vs. tool type 0-1 incidence matrices) on the basis of expert opinions about the characteristics of such data. In the first stage, row-sums and column-sums of the tool requirement matrix are sampled from two user-specified multivariate normal distributions subject to the feasibility condition that the row- and column-sums yield the same grand total. In the second stage, the binary values of the matrix elements are determined by means of a heuristic. The resultant matrix reflects the desired characteristics, such as part type similarities and tool usage dependencies View full abstract»

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  • Impact of C-130 reliability and maintainability on future theater airlift system productivity

    Publication Year: 1991 , Page(s): 542 - 548
    Cited by:  Papers (2)
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    The US Air Force has been actively investigating the near-term acquisition of a new transport aircraft to provide improved intratheater airlift capability into the 21st century. The new transport aircraft will augment the current intratheater, or theater, airlift fleet, which is composed almost exclusively of C-130 aircraft. The new theater airlifter concept under consideration, referred to as the Enhanced Theater Airlifter, is to have reliability and maintainability attributes double that of a C-130E. The authors examine the impact of doubling the reliability and maintainability (R&M) of generic C-130 fleets on a future theater airlift system's productivity. Doubling the reliability and maintainability of the generic C-130 was shown to give statistically significant benefits. Specifically, doubling the C-130's R&M (1) increases its productivity by 6% in tons delivered and 4.5% in tons on time, (2) increases its responsiveness, and (3) increases fully mission capable rates 12%. Improvements to the C-130's reliability contribute more to increasing its productivity than do improvements to its maintainability View full abstract»

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  • Simulation model verification and validation

    Publication Year: 1991 , Page(s): 37 - 47
    Cited by:  Papers (13)  |  Patents (1)
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    Verification and validation of simulation models are discussed. The different approaches to deciding model validity are described; how model verification and validation relate to the model development process is specified; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; ways to document results are given; and a recommended validation procedure is presented View full abstract»

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  • On the performance of the immediate restart concurrency control policy

    Publication Year: 1991 , Page(s): 669 - 676
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    The authors study the performance of a concurrency control algorithm based on locking, called the immediate restart. Under this policy a transaction that fails in acquiring a lock is immediately absorbed (and replaced by another transaction to maintain the same multiprogramming level). The aborted transaction is attempted once again after some delay. The authors discuss the factors that influence the algorithm performance, namely data contention and resource contention. It is argued that selecting the appropriate delay is crucial to the performance of policy. A novel method for calculating the restart delay that takes into account the current state of system resources is proposed and shown to yield better performance than the traditional method which uses the running average of transaction response time under both uniform and nonuniform access View full abstract»

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  • Dynamic traffic flow planning for ATC and airspace user requirements

    Publication Year: 1991 , Page(s): 747 - 755
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    It is pointed out that airline deregulation and associated cost factors have increased the operational need for airspace users and providers of the air traffic control (ATC) service to define new methods of providing airspace operational improvements. Some of these improvements will result from the use of integrated traffic flow planning and management systems that dynamically adapt to the changing operational environment. The authors describe the development and application of new technology and concepts that meet the challenges of providing improved airspace utilization that is integrated with users' operational needs and ATC system capabilities. Examples of the use of simulation and modeling in the air transportation system that consists of the users and ATC providers are presented. It is pointed out that the ATC providers have as the primary objective safety followed by the optimal use of airspace resources. The users' system seeks to maximize operational efficiency, which translates to economic performance. A users' flight planning system only considers single aircraft in the planning. This points to the need for increased integration of the user and ATC systems from the system perspective. This translates to a total system objective of providing the best operational condition for an airspace user in the presence of competition between users for system resources View full abstract»

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  • Material handling requirements for a distribution center

    Publication Year: 1991 , Page(s): 396 - 401
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    The author describes a phased modeling approach used to evaluate material handling alternatives and operational changes for a high-volume food packaging, warehousing, and distribution plant. The goals of the project were to recommend methods for improving both throughput and storage capacity within the existing facility in order to accommodate anticipated increases in inventory and customer order volume. Detailed micro models were developed for the major material handling systems to examine different equipment configurations and operational procedures. Once the best alternatives were identified in each area of the facility, a macro model encompassing the entire distribution facility was developed. The macro model was used to evaluate throughput, material flow, material handling equipment utilization, and resource allocation View full abstract»

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  • An overview of derivative estimation

    Publication Year: 1991 , Page(s): 207 - 217
    Cited by:  Papers (13)
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    The author explains the main techniques for estimating derivatives by simulation and surveys the most recent developments in that area. In particular, he discusses perturbation analysis, likelihood ratios, weak derivatives, finite differences, and many of their variants. Some other approaches are also mentioned. The emphasis is on the relationships between the methods. For that purpose, they are presented in the same framework View full abstract»

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  • On improving pseudo-random number generators

    Publication Year: 1991 , Page(s): 1035 - 1042
    Cited by:  Papers (1)
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    The authors provide some theoretical justifications for the asymptotic uniformity and asymptotic independence of the combination generators without the usual assumption of independence of the generators. The theorems presented give a general method of transforming a possibly bad generator into a much better generator which will yield an asymptotically independent and uniformly distributed random sequence. An empirical study demonstrates that only a small number of terms is required in the author's asymptotic theory to achieve a much more uniform random sequence. As pointed out by S.K. Park and K.W. Miller (1988), some generators provided by certain computer systems may not be very random. Combining several generators into a single generator will provide some protection against the possibility of bad system-provided generators View full abstract»

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  • Parallel simulation of performance Petri nets: extending the domain of parallel simulation

    Publication Year: 1991 , Page(s): 564 - 573
    Cited by:  Papers (13)
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    The authors present a parallel simulation protocol for performance Petri nets (PPNs), nets in which transition firings take randomly selected amounts of time. This protocol is interesting for two reasons. First, application of standard conservative or optimistic parallel simulation to PPNs results in either unnecessarily low (possibly no) parallelism or simply fails to produce correct results. Thus, this protocol may be thought of as addressing a class of models not amenable to standard parallel simulation, with PPNs being a particular example. Second, PPNs are currently analyzed using numerical techniques that have time and space requirements exponential in the size of the net. Simulation, particularly parallel simulation, is thus a practical alternative analysis method for these models, as is shown by measurement of execution times. The authors introduce a technique called selective receive that loosens a fundamental rule of conservative parallel simulation by allowing model components to sometimes ignore certain of their input channels and thus to determine their local clock times based on only a subset of their potential inputs View full abstract»

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  • MTW: an empirical performance study

    Publication Year: 1991 , Page(s): 557 - 563
    Cited by:  Papers (4)  |  Patents (1)
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    The authors present some performance results for the Moving Time Window (MTW) parallel simulation control protocol: a scheduling paradigm for parallel discrete-event simulation. MTW supports both optimistic and conservative event execution models via a time window. The time window constrains simulation object asynchrony by temporally bounding the difference in local simulation time between objects. MTW also provides a hierarchy of synchronization alternatives aimed at reducing simulation execution time, while maintaining temporal integrity. The authors describe the MTW paradigm in some detail, proposing several initial hypotheses regarding MTW performance, and present experimental evidence to support these hypotheses View full abstract»

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  • Incorporating simulation into a design environment

    Publication Year: 1991 , Page(s): 1180 - 1186
    Cited by:  Papers (1)
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    The author describes a methodology that provides a simulation capability for certain kinds of software environments. The required simulation functions are partitioned into a number of well-defined functional roles that represent basic units from which discrete event simulation programs can be constructed. A novel approach to constructing modeling environments is used. To insulate the users from many of the software integration details, the environment uses explicit knowledge of its own structure to support the user in selecting and adapting the system components. The knowledge is in the form of wrappings, which are expert interfaces to the programs, tools, and other resources in the environment. This approach is a simple and powerful mechanism for making many different kinds of resources available to work together in an integrated way. The author defines the functional roles in an existing set of discrete event simulation support functions and describes wrappings for them. He also shows how ordinary differential equation solvers fit into the same framework View full abstract»

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  • Fault-tolerant distributed simulation

    Publication Year: 1991 , Page(s): 637 - 641
    Cited by:  Papers (1)
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    The author considers two kinds of problems that may appear in a distributed discrete-event simulation: the appearance of deadlocks due to unknown lookaheads and processor crashes. Both of the problems are solved by taking global snapshots of the distributed simulation efficiently. It is proved that the recorded global states of the distributed simulation are consistent and can thus be used by the deadlock breaking algorithm and for checkpointing View full abstract»

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