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The purpose of this dissertation is to find the channel capacity in optical fiber communication systems when incoherent detection is used with single (polarization filtering) and two-polarizations (no polarization filtering). Optical fiber systems employ photodetectors that convert optical intensity to electrical current. Bandpass vector fields may be represented by four orthogonal baseband components corresponding to two quadrature phases and two orthogonal polarizations. Intensity is proportional to the sum of the squares of these four components. In the case of a coherent receiver, a strong optical local oscillator (in phase and with same polarization as the signal) is added to the signal prior to the photodetector. This results in the removal of the quadrature phase and polarization components, and reduces to the one degree of freedom (DOF) case of signal plus local oscillator shot noise for which the Shannon channel capacity formula applies. Electrical noise following the photodetector may also be neglected if there is an optical amplifier before the photodetector in the receiver. The amplifier introduces amplified spontaneous emission noise containing both quadrature phase components and both polarizations (4 DOFs), but the 2 DOF case would result if a polarization filter were used. Although the 1 and 2 DOF cases are of less practical interest than the 4 DOF case, they provide useful benchmarks for comparing performance limits. We evaluate both spectral efficiency limits (bps/Hz) in the limit of high and low SNR for the 1,2 and 4 DOF cases and also find the power efficiency (minimum number of photons per bit) for each of these cases. It is shown that for high SNR the spectral efficiency is the same independent of the number of DOFs and that the half-Gaussian distribution is the optimum distribution. We are able to thus obtain a compact equation for spectral efficiency which behaves in a similar way to the Shannon capacity formula but with the SNR scaled by a constant. We also show that for low SNR the half-Gaussian distribution is not the optimum distribution as the slope of the mutual information changes with the square of SNR which would lead to the number of photons per bit becoming infinite in the limit of SNR going to zero. We use a modified half-Gaussian distribution which has a discrete component (an impulse function at the origin) and provide a simple proof that this distribution results in a mutual information that goes to zero linearly with SNR resulting in a minimum number of photons per bit. Furthermore, by increasing the magnitude of the discrete component at the origin, it is shown that the minimum number of photons per bit for the incoherent channel approaches that of the coherent channel. / Ph. D.

In contemporary downtown historic area renovation, conflicts between the new building and the environment always exist. To better solve the problem, a concept of Scene Container was introduced into the New Craig County Hall design, achieved by framing views from the new building towards historic scenery outside. Layered spaces with differing degrees of enclosure also help to build visual contact between new and old. / Master of Architecture

by Simon W.F. Tse. / Thesis (M.A.Ed.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 115-119.

This thesis will identify what career paths, advanced degrees, and supportive industries best enable engineers and other highly technical professionals to move past middle management layers into executive leadership. Specific questions to be addressed include: 1. Which technical degrees most often lead to CEO appointments? 2. Which industries offer the most advancement opportunities for technical degree graduates? 3. Which advanced degrees are most useful for ascension into CEO ranks? This research is specifically geared to extend the key learnings of the University of Texas at Austin Executive Engineering Management curriculum giving the reader foresight into what executive career paths are available for those with technical degrees. / text

Doctor of Philosophy / Department of Electrical and Computer Engineering / Balasubramaniam Natarajan / Dale E. Schinstock / In this dissertation, two applications related to vision-based localization and mapping are considered: (1) improving navigation system based satellite location estimates by using on-board camera images, and (2) deriving position information from video stream and using it to aid an auto-pilot of an unmanned aerial vehicle (UAV). In the first part of this dissertation, a method for analyzing a minimization process called bundle adjustment (BA) used in stereo imagery based 3D terrain reconstruction to refine estimates of camera poses (positions and orientations) is presented. In particular, imagery obtained with pushbroom cameras is of interest. This work proposes a method to identify cases in which BA does not work as intended, i.e., the cases in which the pose estimates returned by the BA are not more accurate than estimates provided by a satellite navigation systems due to the existence of degrees of freedom (DOF) in BA. Use of inaccurate pose estimates causes warping and scaling effects in the reconstructed terrain and prevents the terrain from being used in scientific analysis. Main contributions of this part of work include: 1) formulation of a method for detecting DOF in the BA; and 2) identifying that two camera geometries commonly used to obtain stereo imagery have DOF. Also, this part presents results demonstrating that avoidance of the DOF can give significant accuracy gains in aerial imagery. The second part of this dissertation proposes a vision based system for UAV navigation. This is a monocular vision based simultaneous localization and mapping (SLAM) system, which measures the position and orientation of the camera and builds a map of the environment using a video-stream from a single camera. This is different from common SLAM solutions that use sensors that measure depth, like LIDAR, stereoscopic cameras or depth cameras. The SLAM solution was built by significantly modifying and extending a recent open-source SLAM solution that is fundamentally different from a traditional approach to solving SLAM problem. The modifications made are those needed to provide the position measurements necessary for the navigation solution on a UAV while simultaneously building the map, all while maintaining control of the UAV. The main contributions of this part include: 1) extension of the map building algorithm to enable it to be used realistically while controlling a UAV and simultaneously building the map; 2) improved performance of the SLAM algorithm for lower camera frame rates; and 3) the first known demonstration of a monocular SLAM algorithm successfully controlling a UAV while simultaneously building the map. This work demonstrates that a fully autonomous UAV that uses monocular vision for navigation is feasible, and can be effective in Global Positioning System denied environments.

The purpose of this study was to produce data and information that inform California Community College decision-makers of: (a) extent of variance in California's associate degree definitions and graduation requirements, and (b) perceptions of curricular leaders regarding the variances. Associate degree definitions and graduation requirements were compiled and analyzed from the 1997-98 catalogs for the 106 institutions. Degrees offered, number of general education units required, level of English and math required, transfer patterns, and general studies degree patterns were compiled in tables. The interpreted data from the catalog research were confirmed by the articulation officers. Chief Instructional Officers and Curriculum Chairs at each college were surveyed regarding the degree variations and graduation requirements. Were the differences considered problems or issues for the California Community College system? The catalog review findings indicated that a quarter of the colleges define the degrees in terms of purpose (transfer or occupational) while three-quarters define the degree by major or discipline. The minimum number of general education units required to earn an associate degree range from the legal minimum of 18 semester units to as many as 41 units. One-third of the colleges require freshman English composition while others accept a course one level below. Titles used for transfer general education programs are the same titles used for non-transfer or general studies programs at other colleges. The AA in Liberal Arts is comprised of transfer general education on some campuses, while it is a general studies degree on others. A majority of the leaders surveyed agreed that the California Community College system should work toward developing common definitions for associate degrees. The leaders supported offering the Associate of Applied Science degree. The study concluded that Associate degrees vary so significantly among the 106 campuses of the California Community College system that there is no common meaning to the degree. Associate degree definitions in California have no relationship to the definitions set by the American Association of Community Colleges. The study recommended that an Associate Degree Task Force be convened to study the issue and present recommendations to the California Community College Board of Governors. / Graduation date: 2000

The purpose of this study was to describe the transitions, support, and current activities of students who completed baccalaureate degrees after completing community college non-transfer degrees. The population was limited to students who earned an associate degree of Applied Science, Science, or General Studies from Oregon community colleges, and who completed a baccalaureate degree from Portland State University. A telephone questionnaire was used to collect descriptive data and anecdotal information. At the time of community college entry, only 15% of participants identified "transfer" as their reason for attendance, yet each participant in this study did go on to transfer and complete a baccalaureate degree. Half began their community college enrollment after age 22 and excluding previous post-secondary education experience took 6-10 years to complete their baccalaureate degree. At the time of this study, a surprising 33% were enrolled in graduate study. Examining the transitions in retrospect from baccalaureate degree completion, the participants relied upon faculty, family, and employment networks to complement their personal goal-strength. In addition, participants identified an initial reliance on student services for information, especially in maximizing credits used in transfer. However, more than half of the participants identified inconsistent information from services and therefore used their support network of faculty, family, and employment members to obtain information relating to academic success, transfer requirements, and degree completion. The study concluded that no educational program is necessarily terminal, that community colleges cannot configure programs that meet all learner needs, and that the availability and quality of information are catalysts for student goal-achievement. The principle implication of this research is that readily accessible and reliable information of the baccalaureate degree structure is essential to students in community college non-transfer associate degrees programs. / Graduation date: 1997

Multiple-Input Multiple-Output (MIMO) systems are viewed as the last available supply for the ever-growing demand on higher data rates in modern wireless communication systems. Smart exploitation of the traditional wireless resources (time-slots or bandwidth under the same transmit power level) has reached its saturation point. By making better use of the free space between the radio links, based on the multipath radio wave propagation, MIMO systems have shown significant capacity improvement with the same traditional wireless resources. In this multi-disciplinary research, we are exploring the link between the electromagnetic propagation and the information theory. Unlike the majority of recent research work, we model the propagation channel matrix between the transmit/receive elements in a deterministic manner under the Maxwellian framework. Having included the environment properties and the characteristics of the radiating elements, the deterministic approach provides a realistic assessment of the MIMO system performance in specific scenarios. The problem addressed in this research is the evaluation of the multi-antenna systems degrees of freedom (DOF) by employing all the available electromagnetic diversity resources (spatial, pattern and polarization). Based on a developed well-defined power independent dimensionality (PID) metric, we start by investigating the information-bearing potential of the collocated multi-polarization MIMO system. We study the hexapole system (exploiting both electric and magnetic fields in conveying independent information) and compare it to the tripole systems (exploiting the vectorial polarization diversity of one field only). We present numerical results for 3 deterministic scenarios: a canonical free-space (near and far field exact solution), a canonical perfect electric conductor (PEC) corridor using rigorous modal analysis, and a lossy-wall corridor using image ray tracing (IRT). Next, we provide deterministic results for the more interesting sampling problem of the electromagnetic vector fields: given a specific MIMO array size, what is the optimum number of packed multi-polarization antennas (i.e. multi-polarization 1D, 2D or 3D sampling) that yields the largest PID for a given environment and what is the estimate of this PID? Using a canonical case of multi-polarized arrays inside a multipath-rich PEC corridor, we show that the spatial frequency spectrum of the electromagnetic field governs the optimum PID of the site-specific scenario. The problem is analogous to the DOF determination of an essentially time-limited-band-limited 1D scalar function using the framework of the prolate spheroidal wave functions. We also present simulation results for the same sampling problem in a lossy-wall indoor environment using IRT.

Multiple-Input Multiple-Output (MIMO) systems are viewed as the last available supply for the ever-growing demand on higher data rates in modern wireless communication systems. Smart exploitation of the traditional wireless resources (time-slots or bandwidth under the same transmit power level) has reached its saturation point. By making better use of the free space between the radio links, based on the multipath radio wave propagation, MIMO systems have shown significant capacity improvement with the same traditional wireless resources. In this multi-disciplinary research, we are exploring the link between the electromagnetic propagation and the information theory. Unlike the majority of recent research work, we model the propagation channel matrix between the transmit/receive elements in a deterministic manner under the Maxwellian framework. Having included the environment properties and the characteristics of the radiating elements, the deterministic approach provides a realistic assessment of the MIMO system performance in specific scenarios. The problem addressed in this research is the evaluation of the multi-antenna systems degrees of freedom (DOF) by employing all the available electromagnetic diversity resources (spatial, pattern and polarization). Based on a developed well-defined power independent dimensionality (PID) metric, we start by investigating the information-bearing potential of the collocated multi-polarization MIMO system. We study the hexapole system (exploiting both electric and magnetic fields in conveying independent information) and compare it to the tripole systems (exploiting the vectorial polarization diversity of one field only). We present numerical results for 3 deterministic scenarios: a canonical free-space (near and far field exact solution), a canonical perfect electric conductor (PEC) corridor using rigorous modal analysis, and a lossy-wall corridor using image ray tracing (IRT). Next, we provide deterministic results for the more interesting sampling problem of the electromagnetic vector fields: given a specific MIMO array size, what is the optimum number of packed multi-polarization antennas (i.e. multi-polarization 1D, 2D or 3D sampling) that yields the largest PID for a given environment and what is the estimate of this PID? Using a canonical case of multi-polarized arrays inside a multipath-rich PEC corridor, we show that the spatial frequency spectrum of the electromagnetic field governs the optimum PID of the site-specific scenario. The problem is analogous to the DOF determination of an essentially time-limited-band-limited 1D scalar function using the framework of the prolate spheroidal wave functions. We also present simulation results for the same sampling problem in a lossy-wall indoor environment using IRT.