7380263
Getting more from the data in a multinomial selection problem
We consider the problem of determining which of k simulated systems is most likely to be the best per former based on some objective performance measure. The standard experiment is to generate v in dependent vector observations (replications) across the k- systems. A classical multinomial selection pro cedure, BEM (Bechhofer, Elmaghraby, and Morse), prescribes a minimum number of replications so that the probability of correctly selecting the true best system meets or exceeds a prespecified probability. Assuming that larger is better, BEM selects as best the system having the largest value of the performance measure in more replications than any other. We propose using these same v replications across k systems to form vk pseudoreplications (no longer in dependent) that contain one observation from each system, and again select as best the system having the largest value of the performance measure in more pseudoreplications than any other. We expect that this new procedure, AVC (all vector comparisons), dominates BEM in the sense that AVC will never require more independent replications than DEM to meet a prespecified probability of correct selection. We present analytical and simulation results to show how AVC fares versus BEM for different underly ing distribution families, different numbers of populations and various values of v. We also present results for the closely related problem of estimating the probability that a specific system is the best.
8365397
Input modeling when simple models fail
A simulation model is composed of inputs and logic; the inputs represent the uncertainty or randomness in the system, while the logic determines how the system reacts to the uncertain elements. Simple input models, consisting of independent and identically distributed sequences of random variates from standard probability distributions, are included in every commercial simulation language. Software to fit these distributions to data is also available. In this tutorial we describe input models that are useful when simple models are not.
13902265
Simulation and the semantic Web
One of the missions of the semantic Web is to put more knowledge on the Web in an organized fashion and link it to other information and data sources. Three successively more capable languages are (or will soon be) provided for this: RDF, OWL, and SWRL. This paper makes a case for using all three for the domain of modeling and simulation. Based on experience developing the discrete-event modeling ontology (DeMO) some observations on the issues and challenges involved in creating such ontologies are presented. An approach for decomposing models into behavioral and observable parts, a la hidden Markov models, which can make ontologies smaller and easier to understand, is also discussed
6116918
Enhancing Web Services Description and Discovery to Facilitate Composition
Web services are in the midst of making the transition from being a promising technology to being widely used in the industry. However, most efforts to use Web services have been manual, thus slowing down the ever changing and dynamic businesses of today. In this paper, we contend that more expressive descriptions of Web services will lead to greater automation and thus provide more agility to businesses. We present the METEOR-S front-end tools for source code annotation and semantic Web service description generation. We also present WSDL-S, a language created for incorporating semantic descriptions in the industry wide accepted WSDL, by extending WSDL 2.0.
1650301
The spreadsheet interface: A basis for end user programming
16289956
Scenario management in Web-based simulation
Internet communications in general and the World-Wide Web specifically are revolutionizing the computer industry. Today, the Web is full of important documents and clever applets. Java applets and servlets are beginning to appear that provide useful and even mission critical applications. From the perspective of simulation, a future Web will be full of simulation models and large amounts of simulation-generated data. Many of the models will include two or three dimensional animation as well as virtual reality. Others will allow human interaction with simulation models to control or influence their execution no matter where the user is located in the world. Analysis of data from Web-based simulations involves greater degrees of freedom than traditional simulations. The number of simulation models available and the amount of simulation data are likely to be much greater. In order to assure the quality of data, the execution of models under a variety of scenarios should be well managed. Since the user community will also be larger, quality assurance should be delegated to agents responsible for defining scenarios and executing models. A major element of simulation analysis is the analysis of output data, which manages the execution of simulation models, in order to obtain statistical data of acceptable quality. Such data may be used to predict the performance of a single system, or to compare the performance of two or more alternative system designs using a single or multiple performance measures.
14285847
Finding a substrate for federated components on the Web
Recent developments in software component technology have renewed the promise of reusable software. Combining this with the possibilities of sharing simulation results and models using the Internet makes these new developments all the more important, particularly for Web-based simulation. Interoperability standards and data interchange standards (e.g., XML) help facilitate having simulation models interact with other simulation models as well as other information technology components. This paper examines newer component technologies such as Enterprise Java Beans (EJB) and Jini in a search for an ideal substrate for Web-based simulation. Components will need distributed capabilities as well as the ability to flexibly and dynamically join an existing group of interacting components (referred to as a federation).