This study explored the classroom learning environment in science among kindergarten students. In particular, I investigated both students' and their parents' perceptions of both preferred and actual learning environments. Additionally, I explored associations between student outcomes (achievement and attitudes toward science) and the nature of the classroom learning environment (as perceived by students and by their parents). The study involved the construction and validation of a learning environment questionnaire that was used by both parents and kindergarten students. Although the questionnaire was validated for use with five- and six-year-old kindergarten students, the same format was used for both parents and students. Prior learning environment studies (Fraser, 1998a) typically have involved the use of questionnaires neither by parents (with a notable exception being the recent study by Allen and Fraser, 2002) or by such young students. There is little doubt that, in just two decades, the field of classroom learning environment has progressed enormously (Fraser, 1998a) and that research involving qualitative methods and research involving quantitative methods each have made outstanding contributions to this overall progress (Tobin & Fraser, 1998). A historical look at the field of learning environments over the past few decades shows that a striking feature is the availability of a variety of economical, valid and widely applicable questionnaires for assessing student perceptions of classroom environments (Fraser, 1998b). This learning environment study is significant not only because it involves very young students (kindergarten) and their parents, but also a classroom learning environment questionnaire was developed and validated in Spanish, for both students and parents. / The design of the study involved a sample of 172 kindergarteners from six classes and 78 parents of the same students from the same six classes. The ethnic make-up for this group of 172 students was 11.8% White, 49% Black, 33.6% Hispanic, and 5.6% of other nationalities. The gender breakdown was 40.4% boys and 59.6% girls. Approximately 45% of the kindergarten student population was made up of English Speakers of Other Languages (ESOL) students. The instruments used included modified versions in English and Spanish of the What Is Happening In This Class (WIHIC)? questionnaire and of the Test of Science-Related Attitudes (TOSRA). A major finding of the study was that the modified version of the What Is Happening In This Class? (WIHIC) questionnaire in the English and Spanish languages displayed satisfactory factorial validity and internal consistency reliability when used with kindergarten students and their parents. Secondly, parents perceived a more favorable actual classroom environment than did kindergarten students, but students preferred a much more favorable classroom environment than did their parents. The magnitudes of differences between students and parents are greater for the preferred form than the actual form. Finally, statistically significant associations were found between kindergarten students' perceptions of the. classroom environment and the outcomes of achievement and attitudes to science.

Bibliography: leaves 282-296.

In this dissertation, multi-rate array (MRA) architecture and its synthesis are proposed and developed. Using multi-coordinate systems (MCS), a unified theory for mapping algorithms from their original algorithmic specifications onto multi-rate arrays is developed. A multi-rate array is a grid of processors in which each interconnection may have its own clock rate; operations with different complexities run at their own clock rate, thus increasing the throughput and efficiency. A class of algorithms named directional affine recurrence equations (DARE) is defined. The dependence space of a DARE can be decomposed into uniform and non-uniform subspaces. When projected along the non-uniform subspace, the resultant array structure is regular. Limitations and restrictions of this approach are investigated and a procedure for mapping DARE onto MRA is developed. To generalize this approach, synthesis theory is developed with initial specification as affine direct input output (ADIO) which aims at removing redundancies from algorithms. Most ADIO specifications are the original algorithmic specifications. A multi-coordinate systems (MCS) is used to present an algorithm's dependence structures. In a MCS system, the index spaces of the variables in an algorithm are defined relative to their own coordinate systems. Most traditionally considered irregular algorithms present regular dependence structures under MCS technique. Procedures are provided for transforming algorithms from original algorithmic specifications to their regular specifications. Multi-rate schedules and multi-rate timing functions are studied. The solution for multi-rate timing functions can be formulated as linear programming problems. Procedures are provided for mapping ADIOs onto multi-rate VLSI systems. Examples are provided to illustrate the synthesis of MRAs from DAREs and ADIOs. The first major contribution of this dissertation is the development of the concrete, executable MRA architectures. The second is the introduction of MCS system and its application in the development of the theory for synthesizing MRAs from original algorithmic specifications. / Graduation date: 1995

The Weapon Target Assignment (WTA) problem is a fundamental problem arising in defense-related applications of operations research. This problem consists of optimally assigning n weapons to m targets so that the total expected survival value of the targets after all the engagements is minimum. The WTA problem can be formulated as a nonlinear integer programming problem and is known to be NP-complete. There do not exist any exact methods for the WTA problem which can solve even small size problems (for example, with 20 weapons and 20 targets). Though several heuristic methods have been proposed to solve the WTA problem, due to the absence of exact methods, no estimates are available on the quality of solutions produced by such heuristics. In this paper, we suggest linear programming, integer programming, and network flow based lower bounding methods using which we obtain several branch and bound algorithms for the WTA problem. We also propose a network flow based construction heuristic and a very large-scale neighborhood (VLSN) search algorithm. We present computational results of our algorithms which indicate that we can solve moderately large size instances (up to 80 weapons and 80 targets) of the WTA problem optimally and obtain almost optimal solutions of fairly large instances (up to 200 weapons and 200 targets) within a few seconds

M.S. / Computer Science & Engineering / Some biological aspects of neural interactions are presented and used as a basis for a computational model in the development of a new type of computer architecture. A VLSI microarchitecture is proposed that efficiently implements the neural-based computing methods. An analysis of the microarchitecture is presented to show that it is feasible using currently available VLSI technology. The performance expectations of the proposed system are analyzed and compared to conventional computer systems executing similar algorithms. The proposed system is shown to have comparatively attractive performance and cost/performance ratio characteristics. Some discussion is given on system level characteristics including initialization and learning.

M.S. / Computer Science / A general river routing algorithm is described. It is assumed that there is one layer available for routing and the terminals are on the boundaries of an arbitrarily shaped rectilinear routing region. All nets are two terminal nets. No crossover is permitted between nets. A minimum separation must be maintained between wires to prevent design rule violations. The separation and default width for all nets are obtained from a parameter file. A command line option permits the user to change the width. The algorithm assumes no grid on the routing plane. The number of corners in a given route is reduced by flipping corners.

We consider the uplink of a multicell multiuser single-input multiple-output system where the channel experiences both small and large-scale fading. The data detection is done by using the linear zero-forcing technique, assuming the base station (BS) has perfect channel state information of all users in its cell. We derive  new, exact analytical expressions for the uplink rate, symbol error rate, and outage probability per user, as well as alower bound on the achievable rate. This bound is very tight and becomes exact in the large-number-of-antennas limit. We further study the asymptotic system performance in the regimes of high signal-to-noise ratio (SNR), large number of antennas, and large number of users per cell. We show that at high SNRs, the system is interference-limited and hence, we cannot improve the system performance by increasing the transmit power of each user. Instead, by increasing the number of BS antennas, the effects of interference and noise can be reduced, thereby improving the system performance. We demonstrate that, with very large antenna arrays at the BS, the transmit power of each user can be made inversely proportional to the number of BS antennas while maintaining a desired quality-of-service. Numerical results are presented to verify our analysis.

The effective acyl flux between phospholipids and neutral lipids is critical for a high level of the biosynthesis of very long chain polyunsaturated fatty acids (VLCPUFAs) such as arachidonic acid (ARA,20:4-5,8,11,14), eicosapentaenoic acid (EPA, 20:5-5,8,11,14,17) and docosahexaenoic acid (DHA, 22:6-4,7,10,13,16,19) which are essential for human health and wellbeing. Three membrane-bound enzymes, phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), cholinephosphotransferase (CPT) and ethanolaminephosphotransferase (EPT) from VLCPUFA-producing fungi were selected as candidates for my thesis research based on the hypothesis that these enzymes play important roles in acyl trafficking between phosphatidylcholine (PCs) and diacylglycerols (DAGs) during the biosynthesis of VLCPUFAs. Two putative PDCT cDNAs (PiPDCT1 and PiPDCT2) were cloned from Phytophthora infestans which encode polypeptides with two conserved domains and about 15% of amino acid identity to an Arabidopsis PDCT. However, in vitro assays in yeast Saccharomyces cerevisiae showed they did not have any PDCT activity. Four putative CPT and EPT cDNAs (PiCPT1, PiCPT2, PiEPT and TaCPT) were cloned from P. infestans and Thraustochytrium aureum which encode proteins with a conserved CDP-alcohol phosphotransferase motif and 22% to 26% of amino acid identity to the yeast CPT. In vitro assays indicated PiCPT1 and TaCPT had CPT activity, PiEPT had EPT activity and PiCPT2 did not have either activity. Substrate specificity assays showed that all the three functional CPT and EPT preferred VLCPUFA-containing DAGs as substrates with PiCPT1 being the most specific towards ARA-DAG and DHA-DAG. Real-time qPCR analysis revealed that the expression of PiCPT1 was up-regulated in P. infestans fed with exogenous VLCPUFAs. These results lead us to conclude that PiCPT1 is a VLCPUFAs-specific CPT which may play an important role in shuffling VLCPUFAs from phospholipids to storage neutral lipids, would thus have potential use in metabolic engineering of VLCPUFAs in heterologous systems including oilseed crops.

Background and aim: Persons sustaining different types of brain injury may experience difficulties with advanced mobility. Both persons with traumatic brain injury (TBI) and persons born with very low birth weight (VLBW) have similar brain abnormalities, such as reduced white matter and connectivity, and may thus experience similar mobility problems. However, few studies have assessed advanced motor abilities, and none have compared mobility functions in adult TBI and VLBW populations. Our aim was to investigate high level mobility functions in adults with TBI and VLBW adults compared to matched controls, and to compare high-level mobility in TBI and VLBW adults. Methods: Participants consisted of 22 subjects (mean age 22.9 ± 2.0 yrs) with chronic traumatic brain injury, and 35 subjects (mean age 22.5 ± 0.7 yrs) born preterm with birth weight (below 1500 grams). Two TBI participants were not able to complete all test items due to pain. The VLBW group included three subjects with cerebral palsy (CP). Each group was matched with its own control group, consisting of 24 subjects each from the same geographical area matched by age and sex. Mean age in the control group was 23.3 ± 1.8 yrs for TBI and 22.8 ± 0.5 yrs for VLBW. Advanced mobility functions were assessed by the High-level Mobility Assessment Tool (HiMAT), which consists of 13 timed mobility tasks, with a maximum total HiMAT score of 54. Results: Mean total HiMAT score in the TBI group was 47.0 ± 7.7 compared to 50.3 ± 3.9 for the controls (U=193, p=0.116). Three of 13 mobility tasks differed significantly from the control group: ‘walking’, ‘walk over obstacle’ and ‘bound non-affected leg’. When the two subjects who reported pain were excluded from the analysis, mean total HiMAT score was 48.9 ± 4.9 (U=193, p=0.264), with ‘walking’ and ‘walk over obstacle’ remaining significantly different from the control group. In the TBI group, nine (40.9%) participants performed at or below the 5th percentile compared to 6 (25%) of the TBI controls. Mean total HiMAT score in the VLBW group was 45.1 ± 7.8 compared to 49.9 ± 3.5 in its control group (U = 256, p=0.011). Five of the 13 mobility task scores were significantly different from the control group: ‘walking backwards’, ‘running’, ‘hop affected leg’, ‘bound affected leg’, and ‘bound non-affected leg’. When the three subjects with CP were excluded, mean total HiMAT score was 46.8 ± 5.5 in the VLBW group (U=256, p=0.033) and three mobility task scores remained significantly different from the controls: ‘walking backwards’, ‘hop affected leg’ and ‘bound non-affected leg’. In the VLBW group, 17 (48.6%) participants performed at or below the 5th percentile compared to 4 (16.7%) of the VLBW controls. When directly compared to the VLBW group, the TBI group had (OR 0.733, CI 0.249 – 2.154) lower risk for performing at or below the 5th percentile, although not significant. Conclusions: Compared to controls, adults with TBI had reduced high-level mobility in specific tasks. Adults born with VLBW had reduced overall high level mobility. Furthermore, the HiMAT seems to be a valuable tool for assessing high-level mobility in VLBW populations, and should be formally tested for further use. Keywords: High-level mobility, high-level mobility assessment tool, traumatic brain injury, very low birth weight

Sound propagation in very shallow water is one of the issues of the ocean acoustic. Because of close distance to the shore and short range to the bottom, the building of sound propagation model in shallow water is much more difficult than in deep water. Even though, the increasing needs of upper-sea construction engineering and near-shore surveillance make this subject more and more important. This study is to build a high sensitive underwater recording system, use it to collect data and to find out which parameters affect the sound propagation in very shallow water most. The study contains underwater recording system construction, shallow water recording experiment and comparison of OASES simulation results and the collective data. The system is constructed with two ITC6050C hydrophones and data acquisition devices. After several tests of reliability, the system is put in the sea area about 10 m depth. And the two hydrophones were moored 1 m above the bottom and 2.5 m below sea surface separately. The experiment use a moving fishing boat motor noise as sound source and the experimental results are shown as the spectrogram of sound field. The computer simulation uses OASES modules to simulate the experimental area and Pekeris waveguide propagation as the theoretical environment of very shallow water. By comparing the simulation results and the collective data ,the study finds out that the major parameters of sound propagation in the experimental area are the pressure sound speed and the depth of the sound source.