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A popular electrical exploration method is controlled source audiomagnetotellurics (CSAMT). Although the CSAMT method has had practical sucess, the theory used in CSAMT interpretation remains limited. The controlled source in CSAMT is a grounded electric dipole placed as far as is practical from the survey area. When the source-receiver separation is large enough, source fields can be adequately modeled by a single plane wave and conventional magnetotelluric interpretation methods can be used. Quite often however, data collected at lower frequencies can not be interpreted with magnetotelluric algorithms. If the electrical distance between source and receiver is too small, mathematical models must explicitly include the dipolar nature of the source fields to accurately model the data. Models which include a dipole source are limited. Most interpretation of CSAMT data is based upon horizontally layered models. In this dissertation, the model of plane layers excited by an arbitrary source is extended to include the effects of lateral changes in layer thickness. The method developed for modeling undulating interfaces mimics nature more accurately than plane-layered models, while preserving the utility of quick evaluation and insight lost to more general numerical methods. While the main emphasis here is on CSAMT applications, the theoretical results are valid for any source type. Topographic effects are modeled for plane wave and magnetic dipole sources. The effects of relief in basement topography on the response of a horizontal loop-loop system are computed and compared with scale-model measurements. CSAMT field data which can not be adequately explained by plane-layered models are analyzed using models with variable layer thickness. The correctness of the theoretical development is verified by comparison with physical measurements. The utility of the theory is illustrated by application to problems which can not be explained by plane-layered models.

Electromagnetic shielding by thin, perfectly conducting, two dimensional cylindrical shells over a lossy earth is investigated. The temporal frequency response of the exterior field due to a line source within the shell is computed for a shell described by a three sided, rectilinear structure whose opening faces the earth. The formulation allows shells of arbitrary cross-sectional shape to be analyzed. The earth is modeled as a homogeneous half-space with a planar boundary and frequency dependent electromagnetic properties. Two solution techniques are presented. In the first, the induced current is obtained through a numerical solution of the electric field integral equation (EFIE) at many discrete frequencies. It is found that the applicability of this formulation is limited since in the case of effective shielding, fields calculated from the EFIE are very sensitive to numerical errors. In the second technique the EFIE is again solved for the currents induced on the shell. The induced currents are used to calculate the electric field in the aperture which is used to solve a combined-source integral equation (CSIE) for the external fields. It is found that the CSIE does not suffer from the numerical ill-conditioning that plagues the EFIE, and is well behaved at all frequencies. Numerical results are presented which indicate that the shell-earth combination is very effective in shielding the internal source. Interior modes are weakly transmitted to the interior for the case of a purely dielectric earth. For a lossy half-space the resonances of the closed shell are enhanced. The related topic of scattering by perfectly conducting objects over a lossy earth is addressed. Numerical formulations for the solution of the integral equations are presented which deal with several troublesome aspects of the problem, including the incorporation of the correct edge singularities.

The dissertation is a description of an analysis and a case study of an Optimization Stage for a Standard Cell oriented silicon compiler. Using the AHPL hardware description language, a complete representation hierarchy (functional, logic, and layout) is proposed for circuits defined at a Register Transfer level. The design of a new class of methods for layout analysis and optimization is based on this hierarchy. A layout evaluation method is based on the analysis of an activity graph derived from a circuit layout. The cost measure for such a graph is defined and used in evaluation of the necessary and sufficient conditions for design optimality (NSCDO). Iterations within the optimization process are controlled using a synthetic measure derived from these optimality conditions. A proposed layout optimization heuristic, derived from NSCDO, allows for better routing channel area utilization without compromising a circuit's timing performance. It is based on an analysis of the timing behavior modifications introduced by the various materials used as interconnectors resulting in an improvement of the load dependency of the output driving capabilities of cells. The dissertation contains an example of a quantitative analysis of a CMOS digital circuit. A system implementing some of the algorithms described above has been written in FORTRAN77.

This thesis describes a new test generating algorithm, depth-first algorithm. This algorithm detects the reconvergent fanout. The controllability and observability measures are included in this algorithm to guide the forward and consistency drives. The major objective of this research is to develop a test vector generatiang algorithm, which is modified from D-algorithm, and to link this algorithm with SCIRTSS programs. This depth-first algorithm is more accurate and more efficient than D-algorithm. Serveral circuits are tested under DF3 and SCR3 and the results are listed in this paper.

A defect detection algorithm applicable for periodic VLSI circuitry is presented in this thesis. Even though the algorithm is based on the reference comparison approach, the periodicity of the circuit eliminates the need for the so called "golden wafer." The suggested algorithm has demonstrated the ability to detect defects of small area (0.023% of the image area). In addition, the algorithm was 93% successful in defect detection and has a false alarm rate of 0.067 per inspected frame, based on testing 20 frames.

This thesis discusses the application of the bond graph modeling technique directly coded into the Dynamic Modeling Language (DYMOLA) for simulating a solar-heated house. Scientists throughout the years have investigated the exploitation of solar radiation for space heating. In this thesis, the physical behavior of such a system is modeled and simulated in a convenient, robust and fast manner. The bond graph modeling methodology has found widespread use in a wide range of systems. DYMOLA is a modeling language well suited to represent bond graphs. DYMOLA is a program generator that can map a topological system description, such as a bond graph, into a state-space description expressed in the form of a DESIRE simulation program.