Graduation date: 1994

Integrated circuits manufactured in current technology consist of millions of transistors with dimensions shrinking into the nanometer range. These small transistors have quiescent (leakage) currents that are increasingly sensitive to process variations, which have increased the variation in good-chip quiescent current and consequently reduced the effectiveness of IDDQ testing. This research proposes the use of a multivariate statistical technique known as principal component analysis for the purpose of variance reduction. Outlier analysis is applied to the reduced leakage current values as well as the good chip leakage current estimate, to identify defective chips. The proposed idea is evaluated using IDDQ values from multiple wafers of an industrial chip fabricated in 130 nm technology. It is shown that the proposed method achieves significant variance reduction and identifies many outliers that escape identification by other established techniques. For example, it identifies many of the absolute outliers in bad neighborhoods, which are not detected by Nearest Neighbor Residual and Nearest Current Ratio. It also identifies many of the spatial outliers that pass when using Current Ratio. The proposed method also identifies both active and passive defects.

Noise variance estimator is very important in communication system which could control the transmission power and help system to reach the maximum capacity. But almost every kind of noise variance estimators assume that channel status is perfectly. Unfortunately the estimation error is always existence. This paper discuss that the maximum likelihood noise variance estimator (ML-NVE) in orthogonal frequency division multiplexing (OFDM) system with estimated channel. We take two kinds of the most popular channel estimation (CE) schemes Least Square (LS) and Modified-Least Square (MLS) as our consideration. And we investigate the situation that the ML-NVE suffered by carrier frequency offset (CFO) due to imperfect synchronization. As result we will show off the mean and variance of ML-NVE in those situations.

Thesis (Ph. D.)--University of Chicago, Dept. of Statistics, June 2001. / Includes bibliographical references. Also available on the Internet.

Electrical generating stations in arid regions produce saline water from their cooling systems. Coal fired plants generate fly ash which is recovered by smokestack scrubbers. This ash typically is disposed in large evaporation ponds, which leave vast ash beds and volumes of saline leachate. Restoration of vegetation and wildlife habitat on ash ponds and other impacted areas is complicated by a lack of high quality water for irrigation. I used saline water generated by plant operations to irrigate species of halophytes. These salt tolerant plants were used to revegetate ash ponds and other degraded sites at two generating stations. Once vegetation was established, it provided habitat for wildlife, forage for domestic ruminants, ornamental landscaping, controlled fugitive dust and reduced wastewater disposal costs. At the Four Corners Plant in New Mexico, 16 accessions of Atnplex canescens were tested in a common garden experiment irrigated with saline water recovered from a drainage system collecting leachate from the plant's ash ponds. Accessions from latitudes similar to Northern New Mexico grew faster and had a higher percentage of survival than accessions from more southern or northern locations. Accessions best adapted to an area would be preferable for revegetation projects. I also studied several species of halophytes (Atnplex canescens, A. lentiformis, Prosopis velutina and Paspalum distichum) planted at the Ocotillo Plant in Tempe, Arizona and irrigated with saline water from the cooling system. The vegetation had high survival and growth rates after transplanting. Ground cover increased from 5% to 60%. Surveys of wildlife were conducted pre and post-transplantion. Birds, rabbits and lizards were significantly more numerous in experimental planted areas than in untreated control plots. Rodent populations were not significantly different between treatments. Halophytes can be used to revegetate areas adjacent to electrical power plants and irrigated with saline waters that are normally discharged. Devoting saline water to revegetation irrigation is a cost effective method of disposal compared to evaporation ponds. Plantings attracted several forms of wildlife. Birds, rabbits and lizards specifically used the plants for food, cover and nesting. I developed an economic analysis which compares costs and benefits of restoration projects using halophytes irrigated with saline wastewater.

No description available.

This work involves numerical integration as well as mathematical integration techniques in computing the bivariate and trivariate normal probabilities. The probabilities have been computed and tabulated for desired ranges of the non-negative values of the random variables, and for some specific values of correlation coefficients, taking the size of the tables into consideration. Formulas, however, also been given to derive the probabilities for negative values of the random variables.Computer programs have also been developed and included to compute the probabilities so as to produce the above mentioned probability tables. These computer programs were run on DECSYSTEM-10.

Darbe nagrinėjame ėmimo planus, kurių priklausymo imčiai tikimybės yra dviejų komponenčių mišiniai. Pirmoji komponentė yra proporcinga papildoma informacija nusakytam populiacijos elemento dydžiui, o antroji yra vienoda visiems elementams. Ieškome tokių mišinių, kurie minimizuoja įvairių populiacijos sumos įvertinių dispersijas ir parodome kaip, naudojantis papildoma informacija, apytiksliai nustatyti optimalų mišinį. Pateikiame teorinius ir kompiuterinio modeliavimo rezultatus Poisson'o imtims, renkamoms iš populiacijų, kurios yra generuotos naudojant tiesinės regresijos modelį. / We consider sampling designs, where inclusion (to sample) probabilities are mixtures of two components. The first component is proportional to the size of a population unit (described by means of an auxiliary information available). The second component is the same for every unit. We look for mixtures that minimize variances of various estimators of the population total and show how auxiliary information could help to find an approximate location of such mixtures. We report theoretical and simulation results in the case of Poisson samples drawn from populations which are generated by a linear regression model.

No description available.

Thesis (Ph.D.) - Carleton University, 2002. / Includes bibliographical references (p. 215-222). Also available in electronic format on the Internet.