Interactive Virtual Debugger for GPSS/H

GPSS (General Purpose System Simulator) is a language, designed to aid the computer modeling and simulation of a wide variety of different real life systems. As with any other large programming project, debugging GPSS programs is unavoidable and often difficult. The present thesis describes an Interactive Visual Debugging System for GPSS/H which attempts to simplify the debugging task by allowing the programmer to observe the actual behavior of the model in simulated real time, while preserving all traditional interactive debugging tools - breakpoints, system traps, selective displays, etc. The present version of the Interactive Visual Debugger is developed for the UNIX operating system and is written in the ‘C’ programming language. The system can be readily used on all terminals capable of running the UNIX ‘curses’ library package. Because of its modular design, the system can be modified to accommodate additional terminal types, or to run under different operating systems

COuntywide Police Simulation System COPS

COuntywide Police Simulation System (COPS) is a model which simulates the receipt of police, fire, and emergency medical calls at a public safety communications center, with subsequent dispatch of law enforcement officers to police events. The model examines the interaction of exogenous variables, including the type of call, the frequency of calls, the number of telecommunicators on duty, the number of police cars in service, the deployment pattern of the officers, the number of cars to be dispatched, and the dispatch plan. By modifying the values that these variables can hold, the distribution of workload among police officers can be observed, response times and service times can be examined, and dispatching policies can be evaluated. Sensitivity analysis can be performed without disrupting the life-critical nature of the live operation. An interactive component permits the model to also be used as a training tool for police dispatchers. The thesis presents reasons why it is important to gain a better understanding of the delivery of police services. Major considerations in developing a model are explored, especially as they relate to the simulation of police activity. Programs which gather data on event generation times, telecommunicator service times, patrol-unit travel and service times, event waiting times, and the number of cars per call are detailed. A major portion of the thesis examines each module and entity used in the GPSS/H implementation of the simulation model. The important issue of validation is also addressed. Validation strategy, validation programs, and the construction of a benchmark are discussed. An evaluation of the success of the project is presented, with suggested areas for consideration and future research

GPSS Compiler/Simulator

As with any large software project, the first priority of this thesis is program correctness in the GPSS compiler and correct simulation statistics. Several distinct processes are gone through in the construction of any compiler/simulator: development of specifications, indication of the goals, design, implementation, evaluation, and maintenance. The specifications of the GPSS compiler/simulator were introduced in the thesis proposal. The VAX/VMS 11/750 will be the machine which this GPSS compiler/simulator uses because of the supported \u27C language, a Command Language Definition Utility, and accessibility by this author. The implementation language, \u27C, was chosen based on ease of readability, ease of understanding, the simple but powerful data structures in the language, and the language\u27s support of modularization. Three milestones were identified for this thesis project: the parser, the pseudo code generator, and the simulator. Many projects are started with only the end product in mind, but the goals which were identified constitute essential checkpoints to validate the integrity of the compiler/simulator. There were three distinct design phases due to the milestone identification. The parser design encompassed the initial modular design layout of the source code for the entire compiler, and the design of the symbol table. Design of the pseudo code language had two constraints imposed: the ease of representation of the GPSS language in twoaddress code and the ease of integration of the pseudo language into the parser. Last but by no means unimportant was the design of the simulator, which controls the order of events within a model. After each design phase described above was completed, the implementation or writing of the source code was accomplished. The parser, the pseudo code generator, and the simulator carried through the \u27C capabilities of modularization and readability. Evaluation of the compiler was accomplished at three points: after the implementation of the parser, after the implementation of the pseudo code generator, and after the implementation of the simulator. The milestones or checkpoints specified in the identification of goals were essential in verifying the integrity of the system. Although maintenance is not a part of this thesis, the design phase took into consideration the ease of adding functionality to the implemented subset of GPSS. This compiler/simulator could be used as a base from which a more sophisticated and current version of the GPSS language would immerge

Industrial simulation with animation

This thesis examines and evaluates the new simulation language PCModel. Prior to the arrival of PCModel, simulation via computer typically resulted in pages of statistics compiled over the duration of the simulation. PCModel\u27s approach is to simulate the model on the display before the user in real time. Additionally, user interaction is supported to allow changes to be made throughout the simulation run. The evaluation of PCModel is accomplished through inspection of a pair of examples already simulated in a conventional simulation language. The examples show the relative strong and weak points of the language, as well as demonstrating how PCModel is used --Abstract, page ii

Industrial Simulation with Animation

This thesis examines and evaluates the new simulation language PCModel. Prior to the arrival of PCModel, simulation via computer typically resulted in pages of statistics compiled over the duration of the simulation. PCModel\u27s approach is to simulate the model on the display before the user in real time. Additionally, user interaction is supported to allow changes to be made throughout the simulation run. The evaluation of PCModel is accomplished through inspection of a pair of examples already simulated in a conventional simulation language. The examples show the relative strong and weak points of the language, as well as demonstrating how PCModel is used

Construction time-cost model in Croatia

The paper deals with the applicability of the time-cost model for calculating the sustainable construction time for building projects in Croatia. In this model the time is expressed as a function of money in the project, while the specific constants K and B need to be determined. These constants depend on economic characteristics of the country or a larger area, therefore had to be separately calculated for a region with similar economic characteristics. The modelling of the constants was performed for two groups of building projects - the roads and residential and office multi-storey buildings. The obtained results have been analyzed and compared to the corresponding results from abroad

A critical evaluation and comparison of four manufacturing simulators using analytic hierarchy process

In the period of continuous change in global business environment, organizations, large and small, are finding it increasingly difficult to deal with, and adjust to the demands for such change. Simulation is a powerful tool for allowing designers imagine new systems and for enabling them to both quantify and to observe behaviour. Currently the market offers a variety of simulation software packages. Some are less expensive than others. Some are generic and can be used in a wide variety of application areas while others are more specific. Some have powerful features for modelling while others provide only basic features. Modelling approaches and strategies are different for different packages. Companies are seeking advice about the desirable features of software to manufacture simulation, depending on the purpose of its use. Because of this, the importance of an adequate approach to simulation software evaluation and comparison is apparent. This paper presents a critical evaluation of four widely used manufacturing simulators: NX-IDEAS, Star-CD, Micro Saint Sharp and ProModel. Following a review of research into simulation software evaluation, an evaluation and comparison of the above simulators is performed. This paper illustrates and assesses the role the Analytic Hierarchy Process (AHP) played in simulation software evaluation and selection. The main purpose of this evaluation and comparison is to discover the suitability of certain types of simulators for particular purposes

Graphical Programming of Simulation Models in an Object-Oriented Environment

Graphical programming has been used in conjunction with conventional simulation languages via block diagrams or activity networks. Its beneficial effects on programming and modeling in simulation have been accepted by everyone involved in these languages. However, none of these conventional techniques is truely interactive. Given the level of the current hardware and software technology, it is possible to design a very good graphical programming system which supports an interactive incremental programming style in specifications of simulation models. The benefit of such a visual system would go beyond the modeling phase of a simulation study and it might as well be realized in understanding the behavior of complex problems, in being a communication and training medium for the user and developers, and finally in presenting the simulation results. In this study, the graphical programming methodology has been investigated from the perspective of object-oriented simulation. The truely interactive and graphical orientation of some of the object-oriented languages (e.g., Smalltalk-80) has opened up new avenues of research in this very important topic. Today, the nature of this type of research will be not whether it can be done but how the known techniques should be combined to yield the highest benefit