All physical copies are missing page 3 in this thesis. - McMaster Digitization Center / A computer simulation model was developed to simulate the receiving of raw materials at a dock for an integrated steel plant on the North shore of Lake Erie. The model was formulated to study queue build-up, berth waiting time and the effect of various unloading conditions on dock efficiency. A financial analysis, using present value techniques, was then applied to the model results in order to recommend an optimum berth staging plan under various economic conditions. Historical data on raw material receiving at Hilton Works, Hamilton, were collected and used to develop mathematical functions to describe the random nature of vessel arrivals and berth times. It was determined from this data that vessel arrivals are described by a Poisson distribution and berth times are described by an Erlang distribution. The computer model simulates the dock operation by generating random numbers according to these distributions (Monte Carlo Simulation.) Coal and ore vessel arrivals are merged and respective service times generated. Interferences occur and queues grow and diminish as the facility is simulated through the shipping seasons throughout its expected life. Various unloading rates and vessel tonnages are simulated for a single and double berth operation and the associated waiting times and queue lengths are recorded for each alternative. An economic analysis is performed on the alternatives using present value techniques. The economic analysis indicated that the optimum time to expand the dock to a double berth occurs at a tonnage level of 15 million (coal + ore). To reach this level unloading rates of 10,000 TPH for ore and 8,000 TPH for coal would have to be achieved with an average vessel tonnage of 39,000 metric tonnes. Reducing the unloading rates or average vessel tonnage would move forward the required construction of a double berth and would increase the present value for that alternative. This expansion date will also depend on future economic factors such as cost of capital and escalation rate. The other important conclusion drawn from the economic analysis was that the receiving facility should be expanded in minimum feasible increments because of uncertain economic conditions. This concept dictates that conveyors be installed at minimum capacity, i.e. -belt width and drive size, to handle the first stage tonnage only with provision in the equipment to increase capacity by replacing narrow belts with wider ones and adding additional drive units. The timing for the stages is predicted on several factors, such as: life of the initial belt, tonnage forecast, ship delay costs, and most importantly future economic conditions. For example, it would be advantageous to increase the unloading capacity with a wider belt at the time the initial belt is worn out. Belt and drive staging will take place before the expansion to a second berth in order to defer the capital investment as long as possible. The conveyor system for the second berth can be similarily staged. The study indicated that a good planning strategy would be to initially install a 1.8 m wide belt on 2.0 m wide machinery with 3-1,000 H.P. drives. This system would unload ore at approximately 7,000 t/hr. and coal at approximately 5,000 t/hr. This capability could be increased to 10,000 t/hr. for ore and approximately 8,000 t/hr: for coal by adding a 2.0 m wide belt and 1 -1,000 H.P. drive unit. These rates would be compatible with the expected unloading rates of the future fleet. The decision to increase capacity should be considered when the initial belt is worn out or when delay costs and future economics dictate expansion before that time. The study also indicated that it is poor strategy to design the second berth/conveyor system to be restricted to coal receiving only. The Computer simulation indicated ship delay time for the restricted berth to be approximately three times that for a system with capability to receive ore and coal equally at both berths on either conveyor and either stacker. It indicates that ore receiving is the most important capability and should not be restricted. Even though ore pellets unload more quickly the ore tonnage required is twice that for coal. Therefore, it is recommended to design a completely flexible system . with full provision for expansion to higher unloading rates and larger vessels (850 ft.) and with provision to unload equally from either berth to either conveyor and to have the ability to transfer material between converyors at the head end of the stacker conveyor. / Thesis / Master of Engineering (MEngr)

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The purpose of this study was to compare the effect of a computer simulation activity versus a hands-on activity on students' product creativity, originality, and usefulness. Fifty-eight middle school technology education students from Northern Virginia participated in the study. Subjects were randomly assigned to either a computer simulation or hands-on treatment group. The computer simulation group used a Lego-type brick simulator to construct creative products on the computer; whereas, the hands-on treatment group used real LEGO® bricks to construct their creative products. The hands-on groups' products were collected by the researcher and copied into the computer simulation program. Both groups' products were printed using a color printer. The printed products were evaluated by expert judges using a creative product semantic differential scale. This study showed that there was no significant difference in product creativity scores among the computer simulation and the hands-on treatment group. The null hypothesis was accepted. Findings suggested that it was possible to use a computer simulation activity in place of a hands-on activity and still maintain product creativity, originality, and usefulness. / Ph. D.

Two perspective-view electric wheelchair simulators were developed to enable therapists to prescribe electric wheelchair control interfaces better. The simulators may also be used to train clients to use control interfaces. One simulator presented the user with the visual perspective of sitting in a wheelchair. The other gave the visual perspective of being behind the wheelchair. The simulators were developed on a micro-computer to reduce their cost and promote more wide spread use in the rehabilitation fields. This study was to validate the wheelchair simulators by comparing user performance with the simulators to user performance with an actual wheelchair. Four disabled subjects and four able-bodied subjects navigated the simulators and an actual wheelchair through a similar course consisting of a path the width of the wheelchair. Performance measures relating to safety, such as RMS deviation from the path, number of crossings of the path boundaries, and maximum deviation per trial were obtained for both the simulations and the actual wheelchair driving task. Analyses of variance of these performance measures indicate that mean user performance with the simulators tended to be similar to mean user performance with the actual wheelchair. Correlational analyses suggest that performance with the simulators is predictive of relative performance with wheelchair in straight sections of the course. / Master of Science

To facilitate the design of efficient simulation experiments, Schruben and Margolin (1978) recommend a correlation induction strategy for orthogonally blockable experimental designs. The objective of such experiments is to estimate a general linear regression model on the basis of a quantitative response variable generated by the simulation model. Nozari, Arnold, and Pegden (1987) develop optimal statistical procedures for analyzing simulation experiments performed under the Schruben-Margolin correlation induction strategy. Formulas are given for parameter estimation, hypothesis testing, and confidence interval estimation. The validity of this statistical analysis procedure is contingent upon the presence of a pure error component in the response. The goal of this thesis is to provide an appropriate statistical analysis technique for simulation experiments conducted under the Schruben-Margolin correlation induction strategy in the absence of pure error, and to identify conditions under which the pure error component is absent. Often, in order to construct valid inferences on the responses from a simulation experiment, the technique used to execute the simulation experiment must be properly identified. For purposes of this research, the identification problem takes the form of ensuring that the hypothesized metamodel is appropriate for the number of random number streams used to induce correlations between responses across design points. / Master of Science

Functional level modeling techniques for modeling digital devices that vary in complexity from SSI to LSI are described in this thesis. The vehicle used for modeling is GSP, a general simulation program developed under Dr. J. R. Armstrong at Virginia Tech. These techniques have been used extensively for modeling various devices which include counters, RAMs, ROMs, microprocessor peripheral chips and CPUs. Processors modeled include the Intel 8080, the Zilog Z80 (single chip CPUs) and the Bendix BDX930 (MSI). / Master of Science

M.S.

No / A computer simulation based on a Monte-Carlo technique has been developed and used to investigate the influence of pellet size, dispersity, shape and aggregation on the filling of hard shell capsules. The simulations are in general agreement with experimental observations previously reported. The results also confirm recent findings that filling is a function of pellet shape and that above an aspect ratio value of 1.2 filling reproducibility is reduced. The methodology is simple and rapid in execution allowing many computer-based experiments to be performed with minimum effort.

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