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The Brigham Young University (BYU) Radio Astronomy group, in collaboration with Cornell University, the University of Massachusetts, and the National Radio Astronomy Observatory (NRAO), have in recent years developed and deployed PAF systems that demonstrated the advantages of PAFs for astronomy. However, these systems lacked the necessary bandwidth and acquisition times to be scientifically viable. This thesis outlines the development of a 20-MHz bandwidth system that can acquire for much longer periods of time and across much larger bandwidths than previous BYU systems. A report of the deployment of this system on the 305-meter reflector at the Arecibo Observatory in Puerto Rico is also summarized.The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is currently constructing a PAF-equipped synthesis imaging array named the Australian Square Kilometre Array Pathfinder (ASKAP) that offers great promise for widening FOVs and enhancing RFI mitigation techniques. Previous work in RFI mitigation has demonstrated effective cancellation for synthesis imaging arrays under the assumption that the processing bandwidth is narrowband and correlator dump times are short. However, these assumptions do not necessarily reflect real-world instrument limitations. This thesis explores simulated adaptive array cancellation algorithm effectiveness as applied on the ASKAP instrument given realistic bandwidths and correlator dump times. The results demonstrate that active RFI mitigation performed across long baselines is largely ineffectual.

本研究應用系統思考為基礎所發展出來的系統結構圖方法，結合電腦模擬活動，引導學生感知系統動態性及複雜性，設計自然科學教學方案進行教學；同時比較融入概念階層聯結為基礎的概念構圖方法教學、及一般教學的學生認知表現。具體而言，本研究目的為：在自然科學學習歷程中，結合環狀關聯的系統結構圖，及階層關聯的概念構圖方法，比較二圖形學習策略對學生成就測驗及知識結構的表現差異。 研究採多基線實驗研究法，以國小五年級學生樣本，共三個班級，100人，分列為對照組、系統結構圖策略組、及概念構圖策略組。以自編的複本測驗、實作評量檢核表，及應用路徑探測法(Pathfinder)，評估學生認知表現與知識結構。 結果發現，採用系統結構圖策略或概念構圖策略，均能增進學生認知表現，且記憶保留效果會優於不特別採用策略者，其知識結構的表現亦存在差異；而二種圖形式學習策略的各項認知表現之間，不存在任何差異；不同能力組別與不同學習策略間，具交互作用存在。 本研究證實，在學習歷程中，採用概念構圖策略或系統結構圖策略，將比採用一般教學方法，較能有效增進學生的學習表現及保留效果，其知識結構也會較接近專家表現。因此在教學歷程中，結合策略進行教學有其必要性。圖像式的思考及學習方法能有效協助學生學習。然而研究所取用的二種圖形策略的思考本質是不同的，一重視靜態架構、一重視動態因果變化，未來研究者可進一步探究造成改變的內在機制，及是否能真正轉化為習用的思考型態。 / The world of system and system thinking marks a shift from the more linear, analytic way of thinking that most people are used to. A system is a group of interacting, interrelated, or interdependent components that form a complex and unified whole. Systematic structure diagram is a useful tool to offer a glimpse into the complex systems behavior. Concept mapping, known as cognitive maps or organizers, semantic networks, or visual/graphic organizers, make use of figures, lines, arrows, and spatial configurations to show how content ideas and concepts are related. Concept mapping is described repeatedly in the literature as a tool that can support and enhance students’ learning in science classrooms. It is an important meta-cognitive tool in science education today. The research uses the experiment methodology of multiple baselines designs. In the study 100 students in 3 classes at grad 5 were studied to see the implications of the learning results. Assign the subjects to three groups, control group (n=34), Systematic structure diagramming group (n=33), and concept mapping group (n=33). The graphics oriented strategies, Systematic structure diagramming /concept mapping, were used in the teaching processes of the systematic structure diagramming group /concept mapping group. The researcher evaluated the performance of the subjects with duplicated-tests, checklists, and Pathfinder. The testing of the students was done in a pretest-posttests design using written tests. Data were analyzed in the use of three-factor repeated measures. The analysis of repeated measures showed a statistically significant difference in duplicated-tests and knowledge structures between control group and two experimental groups. There also exists an interaction between group and strategy. The result revealed that concept mapping may improve test scores of low-achieving students. This research verified that the learning performances, knowledge structures, organizations, and delayed memories of the subjects who belong to concept mapping strategy group and systematic structure diagramming strategy group were better than control group. The results indicated that, for improving students’ learning performances and retention effects, adapting concept mapping strategy and systematic structure diagramming strategy in the teaching processes may help students form a cognitive schema to assimilate and relate the information. Base on the results from this study, some recommendations educators were suggested.

The primary importance of trajectory reconstruction is to assess the accuracy of pre-flight predictions of the entry trajectory. While numerous entry systems have flown, often these systems are not adequately instrumented or the flight team not adequately funded to perform the statistical engineering reconstruction required to quantify performance and feed-forward lessons learned into future missions. As such, entry system performance and reliability levels remain unsubstantiated and improvement in aerothermodynamic and flight dynamics modeling remains data poor. The comparison is done in an effort to quantitatively and qualitatively compare Kalman filtering methods of reconstructing trajectories and atmospheric conditions from entry systems flight data. The first Kalman filter used is the extended Kalman filter. Extended Kalman filtering has been used extensively in trajectory reconstruction both for orbiting spacecraft and for planetary probes. The second Kalman filter is the unscented Kalman filter. Additionally, a technique for using collocation to reconstruct trajectories is formulated, and collocation's usefulness for trajectory simulation is demonstrated for entry, descent, and landing trajectories using a method developed here to deterministically find the state variables of the trajectory without nonlinear programming. Such an approach could allow one to utilize the same collocation trajectory design tools for the subsequent reconstruction.

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