Sallie V. Sheppard

Knowledge-based simulation model specification

A Knowledge-Based Model Construction (KBMC) system has been developed to automate the model construction phase of the simulation life cycle. The systems underlying rule base in corporates several types of knowledge. This includes domain knowledge that facilitates a structured interactive dialog for the acquisition of a complete model specification from a user. An executable discrete simulation model in SIMAN is automatically constructed by the system from this specification, utilizing model ing knowledge and SIMAN knowledge. We present an overview of the KBMC system and focus on the knowledge-based specifica tion method used in the KBMC system.

A graphical specification system for user-interface design

An environment for creating user interfaces for embedded systems, called the graphical specification system (GSS), is presented. GSS combines graphical and minimal low-level textual specification with a prototyping capability for rapid user-interface design and evaluation. It is part of a larger embedded systems project at Lockheed, called Express. The user interface components, display components, user-machine interaction, interface-application interaction, and executive component are discussed. Two scenarios, developed with GSS tool prototypes, demonstrate how some GSS tools function. One is the construction of a display with two pairs of gauges, one Cartesian and one polar. The other is the design of a display for submarine tracking.<<ETX>>

Graphical specification of user interfaces with behavior abstraction

The Application Display Generator (ADG) is a graphical environment for the design and implementation of embedded system user interfaces. It is a major component of the Graphical Specification Subsystem (GSS) in Lockheeds Express knowledge-based software development environment. ADG gives non-programmers simple and flexible methods for graphically specifying the presentation and behavior of embedded system user interfaces. In the ADG methodology arbitrary presentations are attached to abstract object behaviors. This approach makes it possible to provide unconstrained presentations, intelligent user support, rapid prototyping, and flexible facilities for composing complex objects.

Applying software engineering to simulation

Software engineering is a collection of techniques for developing and maintaining large programs. New techniques are necessary because techniques that work for small programs are inadequate for designing, coding, testing, and maintaining large systems. Although some software engineering techniques require special computerized tools, many are easy to apply and can be used by simulationists working in any environment. In particular, simula tionists can take advantage of chief programmer teams, structured walkthroughs, structured analysis and design, software develop ment systems, structured programming, standardized coding con ventions, and top-down testing.

Automatic development of parallel simulation models in ADA

This paper introduces MultiSim, a prototype, user-oriented tool specifically designed to automate the model development process for parallel simulation models. Targeted toward the simulationist and written in Ada for high transportability among different numbers of processors, MultiSim combines discrete-event simulation knowledge, parallel programming knowledge, and target language knowledge and represents this knowledge in frame-like constructs. Through user interaction, knowledge of the system to be modeled is abstracted and a parallel Ada simulation model is automatically generated based on the knowledge resident within MultiSim.

Automatic model synthesis: using automatic programming and expert systems techniques toward simulation modeling

A Knowledge-Based Model Construction (KBMC) system is described which has been developed to automate the model construction phase of the simulation life-cycle. The system utilizes a knowledge-based approach to automatic programming to build a simulation model and extends the knowledge-based approach to include model specification acquisition. The systems underlying rule base, implemented in the production system paradigm of OPS83, incorporates several types of knowledge. Domain knowledge is used in conjunction with simulation modeling knowledge to facilitate a structured interactive dialog for the acquisition of a complete model specification from a user. Modeling knowledge and target language (SIMAN) knowledge are then used to automatically construct an executable discrete simulation model from this specification. This paper presents an overview of the KBMC system and focuses on various issues involved in the conceptualization and implementation of such a system.

Two approaches to the implementation of a distributed simulation system

This paper describes two approaches to the implementation of distributed simulation currently being pursued at Texas A&M University. The first approach describes the design and the implementation of a distributed simulation system onto a Motorola 68000 based architecture. This approach involves transparently distributing the language support functions of an existing simulation language (GASP) onto multiple processors. The second approach discusses the implementation of simulation support software in a high level distributed processing language. This approach involves the distribution of portions of the simulation model which can be executed in parallel onto multiple processors by the model builder. The paper discusses the details of both the approaches and the current status of their implementation.

PULMONOLOGIST: A computer-based diagnosis system for pulmonary diseases

PULMONOLOGIST is a prototype expert system designed as a decision-making aid for physicians in providing accurate diagnosis and treatment of lung diseases. Disease information in the system has been encoded in the form of rules and schemata. The system has been developed using the expert system building tool ART (Automated Reasoning Tool) from Inference Corporation. This paper gives a brief introduction to the expert system concept, and includes a detailed description of the diagnosis system. This system will be tested against clinical data in future studies.

Graphical extensions for pseudo-code, PDLs, and source code

The control structure diagram (CSD) is a new graphical notation intended to increase the comprehensibility of software described or defined with pseudo-code, PDL, or source code. The CSD is a simple graphical extension to these textual representations that provides for the explicit depiction of the control constructs and control flow at all relevant levels of abstraction. The CSD is supported by a fully operational prototype editor which is presently configured for Pascal or pseudo-code that uses the keywords of Pascal.

ADA multitasking and the single source shortest path problem

Abstract This paper examines the implementation in ADA of several parallel algorithms for solving the single source shortest path problem. The algorithm favor certain parallel architectures: vector machine, tree machine, and a distributed processor environment. The paper gives ADA implementations of the algorithms that attempt to retain the preferential treatment to the particular hardware, and discusses whether with proper translation, preferential efficiency can be maintained.