No description available.

The mine production schedule defines the sequence of extraction of selected mine units over the life of the mine, and consequentially establishes the ore supply and total material movement. This sequence should be optimized so as to maximize the overall discounted value of the project. Conventional schedule approaches are unable to incorporate grade uncertainty into the scheduling problem formulation and may lead to serious deviations from forecasted production targets. Stochastic mine production schedulers are considered to obtain more robust mine production schedule solutions. / The application of stochastic approaches to the mine production schedule problem is recent and additional testing is required to better understand these tools and to define the value of a stochastic solution as compared to the conventional result. Two stochastic schedulers are tested in a low-grade variability copper deposit, optimization parameters are discussed and their results compared with a conventional schedule. / The first method uses a stochastic combinatorial optimization approach based on simulated annealing to address the mine production schedule problem. The method aims for maximization of the net present value (NPV) of the project and minimization of deviations from the production targets. These objectives are attained by incorporating grade uncertainty into the mine production schedule problem formulation. The second method formulates the problem as a stochastic integer programming problem, in which the objective is the maximization of the projects' NPV and the minimization of production targets deviations. The model can also manage how the risk of deviating from the targets is distributed between production periods. / Both stochastic approaches were tested in a low-grade variability copper deposit. In both case studies, the value of a stochastic solution is demonstrated to be higher than the conventional one. This fact demonstrated the misleading results that a conventional schedule may produce and shows the importance of not ignoring the presence of uncertainty when defining the mine production schedule for a project.

No description available.

No description available.

Accurate, efficient and general computational techniques are developed to evaluate the scattering parameters of passive microstrip components composed of discontinuities in microstrip transmission lines on general two layer substrates with single and two level metallization. An open domain model is used. The Electric Field Integral Equation is examined and the Green's function for single and double layer dielectric substrates on a infinite ground plane are reviewed while emphasizing the important computational details to the model, including singularity of the kernel, evaluation of the Sommerfeld Integrals, and interpolation of the Green's functions. In order to model accurately complex circuit geometries, two dimensional currents are used. Different basis functions for expansion and for testing are chosen in order to make the computation more efficient and allow for structures having general shape in the moment method formulation. A transmission line current source is used to model the parameters are flowing in and circuit evaluated out of structure. Structures excitation and the scattering by calculating the currents each of the N-ports of the such as microstrip bends, microstrip crossovers of arbitrary angle, and coupled microstrip discontinuities are analyzed. To validate the model, results of some elementary structures are compared with published results of other models. / Graduation date: 1992

Thesis (Ph. D. - Geosciences)--University of Arizona. / Part of folded illustrative matter in pocket. Includes bibliographical references.

Thesis (Ph.D.) from the Dept. of Civil Engineering, University of Adelaide, 1979. / Typescript (photocopy).

Thesis (D.E.) - Dept. of Electrical Engineering, University of Adelaide.

Thesis (Ph.D.)--Curtin University of Technology. / Includes bibliographical references. Also available as an electronic version via the Internet.

Thesis, Ph.D., University of Hong Kong, 1979. / Also available in print.