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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

A vegetable farm planning model for primary producers

Short, C. Cameron January 1977 (has links)
The objective of the thesis was to construct a deterministic single year, farm planning model that would enable vegetable producers to select an optimal farm plan from among alternative crops and crop production methods so as to maximize farm income consistent with technological and resource constraints and other goals. The model was to be readily adaptable to a wide range of commercial vegetable farmers in Canada but sufficiently flexible to be adaptable to the particular situation of a specific farm. A multiperiod linear programming model was built and validated through its application to a large commercial vegetable farm. The relevant theory of the firm was reviewed with special attention made to the theory's application to vegetable farms. The structure of a linear programming problem was discussed and related to the theory of the firm and vegetable farms. Special emphasis was placed on the problem of modeling the machinery used in vegetable production. The work of agricultural engineers was examined to determine the technological relationships involved in machine operation. Other crop budgeting models which involved the construction of similar planning models for a different sector of the agricultural community, especially the Purdue Crop Budgeting Models were reviewed. The model constructed was able to deal with machinery constraints by building a number of machine operating activities and tractor transfers so that the time constraint for a particular job would consist of any subset of the predefined set of time periods. Standard coefficients were prepared based on engineering formulae for fuel consumption and repair and maintenance costs for tractors. All inputs in the model except repair and maintenance costs were in physical units. This made it necessary to build several different types of purchasing or renting activities but facilitates the interpretation of data and the use of the model in a large number of different situations. The model was validated through its application to a large commercial vegetable farm in British Columbia. The model was run in simulation mode by forcing the model to follow the farm's 1974 crop plan and altering yields and prices to yields and prices that actually occured in that year. In this manner the reliability of the cost coefficients of the input data and the relationships between resources could be evaluated and compared with the results recorded in the farm's CANFARM records. The model was run in optimization mode with expected 1976 prices and yields to demonstrate the use of the model in selecting an optimal farm plan. A total of six plans were prepared based on alternate market and risk constraints and yields. These were compared with the plan selected by the farmer without the aid of the model. A detailed report on one of the farm plans v/as also prepared. / Land and Food Systems, Faculty of / Graduate

GPSSV simulation model of timber harvesting operations

Henkelman, Larry Allan January 1978 (has links)
This thesis provides a methodology for examining forest harvesting operations through simulation. The model is capable of simulating multiple landing, single dump logging configurations. Facility locations, equipment types and numbers, parameters, and functional relationships may be varied so that a wide range of west coast British Columbia logging operations can be represented. The model was written in General Purpose Simulation System V (GPSSV) language. A substantial saving in development cost is realized over a FORTRAN-based simulation. The model allows independent users to make modifications within the program in order to adapt to the particular operating rules and policies of their operations. Model formulation for this thesis is based on an actual west coast logging division. Verification of the model involves a three-stage approach. First, a set of hypotheses and postulates are constructed for the subsystems of the harvesting operation and, secondly, these are empirically tested. Historical data is compared to simulation results in order to confirm that particular subsystems adequately model the real system. Tactical considerations and experimental design regarding model execution are presented. It is shown that antithetic variates can be effectively used to reduce the variance of the mean of a response. An improved truck dispatching routine is developed with the objective of maximizing productivity, subject to the availability of yarding and trucking resources. This policy balances the objectives of minimizing truck travel time, truck delays at landings, and yarding stoppages due to timber "saturated" landings. In comparison with other dispatching policies, productivity can be increased from two to over ten percent. The dispatching algorithm has been programmed for a Hewlett-Packard 9830A desktop computing system. The dispatcher, utilizing radio communications with all of the landings and trucks, can theoretically be supplied with the optimum landing to which a truck should be dispatched. Some other practical applications of the timber harvesting simulation model are discussed. Flexibility in the model, in parameter initialization and the substitution of new relationships, allows the investigation of many features of forest resource planning and machine allocation and scheduling. The determination of equipment requirements for various configurations, the evaluation of new equipment and the comparison of different operating policies can be undertaken with the model. Another benefit derived from the development of the model is an increased understanding of the timber harvesting system which allows the design of better operating policies and greater control within the system. / Forestry, Faculty of / Graduate

Experimental designs for the optimization of statistical simulations /

Eldredge, David Leroy January 1968 (has links)
No description available.

Investigation of a combined photographic and computer simulation technique for use in the study of isolated intersections /

Diewald, Walter Joseph January 1971 (has links)
No description available.

VLSI Multiple Microcomputer Technology Applied to Real-Time Simulators

Kotick, David M. 01 January 1983 (has links) (PDF)
VLSI technology, embodied in state of the art microprocessors and microcomputers, has implied a computer system architecture that offers the possibility for extensive standardization, modularity, and performance improvements that can significantly impact and reduce the lifetime costs of real-time simulators. This report discusses one such system. Both the hardware and software aspects of the system are examined.

Simulation of High Resolution Range and Separation Profiles Using a Stepped Frequency Radar Pulse

Fain, Howard. 01 January 1985 (has links) (PDF)
Single frequency pulse, linear frequency pulse, and stepped frequency pulse are a few of the radar pulse waveforms used to obtain target range information. Using a basic single frequency pulse limits the radar's range resolution by the pulse width, has excessive energy requirements, and is more vulnerable to jamming. With the use of frequency modulation the radar's range resolution can be greatly enhanced. This report deals with some of the issues involved in using stepped frequency pulse trains to obtain high resolution target range and range autocorrelation profiles. Radar returns from stepped frequency pulse trains may be coherently processed to obtain the range profile, or noncoherently processed to obtain the range autocorrelation (or separation) profile. The inverse discrete Fourier transform (DFT-1) of N coherently detected pulse returns from each range cell (where N is the number of pulses in the train) gives the high resolution range profile within that range cell. The DFT of the squared magnitudes of the pulse returns yields the autocorrelation of the range profile (the separation profile). Range resolution is determined by the total bandwidth of the pulse train. Using a Fast Fourier Transform (FFT) algorithm for the DFT a simulation of the radar system is implemented on the University of Central Florida, College of Engineering Research VAX 11/750 computer. This simulation computes and plots the range and separation profiles.

A computer-simulated model for the neuronal circuit mediating the tail-flip escape response in crayfish

Kumar, Pramathesh January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries

Simulation of polymer-deposition controlled trench etching in silicon

Sun, Chin-Yang, 1957- January 1988 (has links)
Reactive ion etching has been used to obtain anisotropic silicon trenches with small sidewall angles. This work demonstrates that the sidewall angle can be controlled by the wafer temperature and there exists an Arrhenius-type relationship among isotropic polymer deposition rate, thickness of polymer, and sidewall angle.

Simulation methods for optical disk drive functions.

DeVore, Scott Lawrence. January 1988 (has links)
Computer simulations of the optical servo functions of optical disk drives are developed and compared with experimental results. The focus control servo is investigated first, with emphasis on the astigmatic focus detection method. A paraxial ray trace, enhanced to allow tolerance studies of tilted and decentered surfaces, is used to calculate the size and orientation of an astigmatic blur on a quadrant photodetector as a function of focus error. The resulting irradiance distribution is integrated over the detector elements and processed to yield typical focus servo signals. A method for simulating generalized astigmatic focus systems, independent of a particular design, is also shown. The simulation results are used to derive normalized tolerance curves for detector misalignment and spot motion. Alignment diagnostics based on the servo signals are also presented. A wavefront aberration model is also developed and used to investigate the focus servo's performance in the presence of common aberrations. Simulations based on diffraction theory are used to investigate the radial tracking servo. Both scalar and vector diffraction theories are considered. The scalar theory is found to be adequate in most cases, while offering a large advantage in computational efficiency. A model for computing the signals detected by scanning the microscopic features of the disk is developed using the optical cross transfer function that describes the imaging characteristics of partially coherent systems. This model is used to investigate push-pull and three beam tracking. Aberrations, data patterns, detector misalignment, and pregroove profile are all examined for their effects on the servo signals. Crosstalk between the focus and tracking error detection is also briefly considered, and a possible extension of the radial tracking servo model to investigate this phenomenon is suggested.


Featherkile, B. Nadine, 1937- January 1986 (has links)
No description available.

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