One of the commonly used simulation approaches is process orientation.
This is based on the use of nodes (or blocks) that perform functions in series. In
spite of the compactness and ease of learning that characterize process-based
simulation, many languages are somewhat complex, primarily the result of the large
number of nodes that users have to deal with and the considerable gulf between a
user's abstract notion of the model and the details required to implement it.
This paper describes a process-based simulation system that integrates
object-oriented programming, visual interactive simulation and graphical model
specification. Object-oriented programming techniques and simulation seem to be a
natural match. The process classes are represented as network blocks or network
nodes, and the process as a network diagram or directed graph. Arcs connect the
nodes and specify the next step in the process. Each block type has its own icon.
Developing an application model requires selecting a set of nodes, connecting them,
and specifying the parameters (such as activity durations and random number
streams) of the nodes through dialog boxes or inspection panels. Nodes have been
designed to accomplish the major requirements in simulation modeling, including
creation and termination of entities, attribute assignment, branching, queues and
resources, activity specification and statistics collection and display. Additional
system features include: statistics manipulation for steady state results, execution
trace utilities, and limited animation capabilities.
The system has been implemented for the NeXT programming environment
using Objective-C. The NeXT includes an extensive object-oriented user interface
library, relatively powerful hardware, and a modern multi-tasking and virtual
memory operating system. Objective-C allows object-oriented concepts such as
inheritance and subclassing while adding only a few constructs to that of the C
language.
The system modeling environment developed in this research enhances the
applicability and usability of high level modeling tools. The program also provides
a platform for further work on the distribution of the modeling process over several
cooperating, communicating applications. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37635 |
| Date | 14 January 1992 |
| Creators | McGregor, Donald R. |
| Contributors | Randhawa, Sabah |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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