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The sponsoring company which manufactures a range of construction equipment, required a study of the concrete industry. This necessitated a world wide survey of mixing equipment, concrete technology and the construction industry.

An inductance can be simulated for microelectronics applications using semiconductor elements (e.g., the "inductance diode"), using circuits containing amplifiers, or using gyrators. The last two methods are considered in this thesis. Several "amplifier methods" have appeared in the literature; these methods are classified into integrating- or differentiatiiig-type circuits, and a differentiating-type circuit is proposed which is believed to be new. Gyrator realization methods are tabulated and compared. An "active gyrator" ("AG") is proposed as a circuit element (it has unequal gyration resistances). The AG behaves much like a gyrator; it can be used to simulate inductance, and an analysis shows that it can be used to make isolators and circulators with a power gain. Methods of realizing an AG with amplifiers are investigated, and an analysis leads to seven 2-amplifier circuits. One of these AG circuits appears "best" for inductance simulation, and this one is investigated experimentally using a transistor circuit. An extensive bibliography of the inductance simulation and gyrator literature is presented. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis describes the design and instrumentation of an opaque contour-tracing scanner for studies in optical character recognition (OCR). Most previous OCR machines have attempted to recognize characters by mask matching, a technique which requires a large and expensive computer, and which is sensitive to small changes in type font. Contour tracing is a promising new approach to OCR. In contour tracing, the outside of the character is followed, and the resulting horizontal and vertical co-ordinates, X(t) and Y(t), of the scanning spot are processed for recognition. Although much additional research is required on both scanner design and processing algorithms, it is expected that an OCR device which uses a contour-tracing scanner will be significantly less expensive than existing multifont recognition machines. In this thesis, four possible contour-tracing scanners are proposed and evaluated on the basis of cost, complexity and availability of components. The design that was chosen for construction used an X-Y oscilloscope and a photomultiplier as a flying-spot scanner. In instrumenting this design, a digital-to-analogue converter, an up-down counter and many other special purpose logic circuits were designed and constructed. The scanner successfully contour traced Letraset characters, typewritten characters and handprinted characters. At the machines maximum speed, a character is completely traced in approximately 10 msec. Photographs of contour traces and the X(t) and Y(t) waveforms are included in the thesis. Although the present system will only trace two adjacent characters, proposed modifications to the system would enable an entire line of characters to be contour-traced. Included in the thesis are recommendations for further research on scanner design. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis is concerned with aspects of a theory of machine perception. It is shown that a comprehensive theory is emerging from research in computer vision, natural language understanding, cognitive psychology, and Artificial Intelligence programming language technology. A number of aspects of machine perception are characterized. Perception is a recognition process which composes new descriptions of sensory experience in terms of stored stereotypical knowledge of the world. Perception requires both a schema-based formalism for the representation of knowledge and a model of the processes necessary for performing search and deduction on that representation. As an approach towards the development of a theory of machine perception, a computational model of recognition is presented. The similarity of the model to formal mechanisms in parsing theory is discussed. The recognition model integrates top-down, hypothesis-driven search with bottom-up, data-driven search in hierarchical schemata representations. Heuristic procedural methods are associated with particular schemata as models to guide their recognition. Multiple methods may be applied concurrently in both top-down and bottom-up search modes. The implementation of the recognition model as an Artificial Intelligence programming language called MAYA is described. MAYA is a multiprocessing dialect of LISP that provides data structures for representing schemata networks and control structures for integrating top-down and bottom-up processing. A characteristic example from scene analysis, written in MAYA, is presented to illustrate the operation of the model and the utility of the programming language. A programming reference manual for MAYA is included. Finally, applications for both the recognition model and MAYA are discussed and some premising directions for future research proposed. / Science, Faculty of / Computer Science, Department of / Graduate

Forty-eight harvesting contractors over 13 state submitted data on cost and production over a period from 2003-2006. Within this group, 30 harvesting contractors submitted data for all four years in the study period. Discussions of logging development is presented in Chapter II focusing on labor and equipment. Data analysis focused on production estimates and cost information from a firm size and regional standpoint in Chapter IV. Analysis of consecutive data in Chapter V focused on shifts over time in labor, equipment and related cost categories. Contractors in the Coastal Plains were most numerous and demonstrated a distinct difference in sub-groups. Piedmont firms were second in number followed by Appalachian and Lake States firms. Consumables costs affected all firms most especially between 2004 and 2005. The number of medium sized firms dropped sharply in 2005 indicating attempts to either reduce operating costs or spread increased operating costs over higher production levels.

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