Graphical programming of simulation models in an object-oriented environment

Abstract

Graphical programming, which is used here to mean creation of simulation models graphically, has been used in conjunction with conventional simulation languages via block diagrams or activity networks. Its beneficial effects on model development in simulation have been generally accepted. However, none of these conventional simulation languages has reached a level of graphical programming that would impact the user's programming task substantially. Today, this is possible with the current software and hardware technology. An interactive incremental programming environment supported by a good graphical programming system that helps automatic model development, specification and verification would be greatly appreciated in modeling in general, but especially in simulation of complex real-life systems. Such a visual system could essentially be a conceptual framework for analysis of the problem at hand and become a means of communication among the people who are involved in development and management of systems. It can also be the friendly interface that forms a communication medium between the modeler and the computer for automatic programming.In this research paper, a prototype graphical programming methodology for modeling and automatic interpretation of simulation problems is developed in the object-oriented environment of the Smalltalk-80 language. The modeler uses a high-level graphical representation formalism based on the activity-cycle diagrams to define simulation models in an interactive mode. These activity-cycle diagrams can then be interpreted into the underlying programming language and executed automatically. Thus, the modeler does not have to know the underlying Smalltalk 80 language in order to use our prototype simulation system. The future expansions to this system will include a simulation object editor, a graphical output view system and a richer high-level concept base for modeling purpose.

Intuitive Simulation Modelling Using Object Oriented Constructs

“…what-if analyses) and Learning. Several researchers (Gordon and McNair (1987), Davis et al (1988), Glicksman (1988), Thomasma and Ulgen (1988), Tseng et al (1988) and Ozden (1991)) and indeed a few software packages such as XCELL+ (Conway and Maxwell 1987) and SIMFACTORY (Tumay 1987) have attempted to automate the model building process. All these implementations however were designed specifically for manufacturing environments and suffer from most of the shortcomings listed in the previous sections.…”

Um Módulo de Análise de Saídas para o ASiA

“…Um número considerável de ferramentas para simulação é encontrado na literatura [8EL87, RAC90,OZD91,FUN91,SWA95,8AN96]. Swain, em [SWA95] apresenta uma revisão de 54 sistemas de simulação, com custo variando de dezenas de milhares de dólares.…”

Extensão do ASiA para simulação de arquiteturas de computadores.

“…Nos ambientes de simulação automáticos, uma característica importante é a programação visual [OZD91]. Utilizando a programação visual o modelo de simulação é criado graficamente na tela.…”

“…A partir deste modelo, o programa de simulação é gerado automaticamente e o usuário interage com este programa fornecendo parâmetros. A saída é também gráfica e o usuário observa o comportamento do sistema através de gráficos ou animações [SHA92,OZD91,MEL85]. A programação visual é particularmente desejável e vantajosa uma vez que o homem pode manipular informações de um modo mais eficiente se estas forem apresentadas graficamente [SPO94].…”

“…A revisão bibliográfica revelou a existência de um número considerável de ferramentas para simulação [RAC90,OZD91,FUN91,SWA95]. Swain, em [SWA95] discute 54 sistemas de simulação, com custos variando de dezenas a milhares de dólares.…”