Kevin J. Healy

Silk : a Java-based process simulation language

We discuss various aspects of the design, implementation, and use of Silk, a general purpose simulation language based on the Java programming language. Silk merges familiar process-oriented modeling structures with powerful object-oriented language features in an intelligent design that will encourage model simplicity and reusability. An important aspect of this design is the use of Java’s builtin support for multithreaded execution which is employed as a means to coordinate the concurrent entity flows in process-oriented simulations. We also demonstrate how the use of JavaBeans supports graphical assembly of Silk modeling components in software environments such as Symantec’s Visual Cafe, IBM‘s VisualAge, and Microsoft‘s J++. It is argued that a language such as Silk is essential to keeping simulation modeling on track with other revolutionary changes taking place in Internet-based computing.

Retrospective simulation response optimization

An approach to simulation response optimization in which a simulation experiment is run in such a manner as to generate optimal solutions is presented. Once the stochastic sample path of a simulation run has been generated, it is sometimes possible to retrospectively solve a deterministic optimization problem or a closely related problem. As demonstrated with some examples from communications and manufacturing, this approach can greatly simplify both the simulation experiment and the simulation model.<<ETX>>

The future of Java-based simulation

Java-based simulation presents a unique opportunity for revolutionary changes in the process of developing simulation models and in the mission of the simulation software firms that provide tools to support the model development process. Java enables a new vision of an industry populated by application-specific specialists who generate compatible and reusable simulation components. These object-oriented components can be developed using inexpensive, professional-quality Java development environments and executed using Internet browser software. This discussion is an overview of the features and future benefits of Java-based simulation. It is targeted at experienced simulation practitioners who understand the limitations of existing tools and the need for object-oriented, standardized and reusable modeling software.

Simulation optimization of (s,S) inventory systems

Various methods have been proposed to conduct simulation optimization for discrete event systems such as manufacturing systems and telecommunications systems. We consider a periodic review (s, S) inventory system and report on simulation experiments with two proposed techniques: a deterministic ‘(retrospective” approach and a gradient-based algorithm.

CINEMA tutorial

CINEMA is a general purpose, microcomputer based, animation system designed to work with the SIMAN simulation language. A sophisticated yet easy to use graphical interface allows users with little or no programming skills to build highly detailed animations of any SIMAN simulation model.

Animation design with Cinema

Cinema is a general purpose animation system designed to work with the SIMAN simulation language. A sophisticated yet easy to use graphical interface supports a variety of graphical functions that allow users with little or no programming skills to build realistic and useful animations.

Scheduling arrivals to a stochastic service mechanism

We consider the problem of scheduling the arrivals of a fixed number of customers to a stochastic service mechanism to minimize an expected cost associated with operating the system. We consider the special case of exponentially distributed service times and the problems in general associated with obtaining exact analytic solutions. For general service time distributions we obtain approximate numerical solutions using a stochastic version of gradient search employing Infinitesimal Perturbation Analysis estimates of the objective function gradient obtained via simulation.