Recent attempts to improve science teaching and learning in Tanzania required teachers to adopt a learner-centred pedagogy. Although researchers widely acknowledge a lack of sustained success in science teachers' adoption of learner-centred pedagogy, the reasons for teachers' reluctance to adopt learner-centred pedagogy remain debated. Various contextual constraints, including resource shortages, overcrowded classrooms, ineffective teacher education, and high-stakes exams, render learner-centred pedagogy unsuccessful. However, in the Tanzanian context, teacher educators and researchers seem to overlook the critical role science teachers' beliefs about science knowledge, teaching, and learning play in their teaching practices. Thus, attempts to identify and address Tanzanian science teachers' deeply held beliefs are uncommon. Therefore, I interviewed six secondary school science teachers to explore their beliefs about science knowledge, teaching and learning and to show how these forms. I also observed their lessons to examine how the teachers' beliefs manifest in their classroom practices. The findings showed that teachers largely espoused ‘traditional beliefs' about science knowledge, teaching, and learning. They viewed science as a fixed body of discrete facts that mirrors natural phenomena. They believe the body of science knowledge is absolute and handed down by omniscient authorities, such as textbooks and teachers. The teachers consistently described teaching science as conveying textbook facts for students to accumulate and reproduce during exams. Social and contextual factors, including teachers' childhood, schooling, and training experiences, as well as the bureaucratic demands, paradoxical curriculum, and students' reticence reinforced these beliefs. Teachers' beliefs, though consistent with their teaching practices, were largely antithetical to the principles and practices of learner-centred pedagogy. Therefore, I propose that Tanzanian secondary school teachers consider their beliefs and the social and contextual conditions of the schools in adopting learner-centred pedagogy. They weigh their beliefs against the social and contextual conditions to decide how to teach. These results suggest that teacher educators and policy makers should seek to transform teachers' beliefs about science knowledge, teaching, and learning through learning trajectories that require teachers to articulate and interrogate their beliefs. Such attempts should consider the social, cultural, and material contexts of the schools in which teachers teach.

A 12-day nitrogen balance study was designed to determine the protein nutritive value of soy flour and soy protein isolate in human adults. By equalizing the essential amino acid patterns of the flour and the isolate, it was considered possible to measure any difference in nutritive value of the two protein sources. The subjects were 18 healthy women ranging in age from 20 to 25 years. A basal diet provided approximately 1.0 gram of nitrogen and 1400 kilocalories per person per day. The soy protein was incorporated into a low-protein yeast bread providing approximately 500 kilocalories per person per day. The following dietary treatments were used: 1. Basal diet plus 4.0 grams of nitrogen supplied by soy flour. 2. Basal diet plus 4.0 grams of nitrogen supplied by soy isolate. 3. Basal diet plus 3.09 grams of nitrogen supplied by soy isolate. Diet 3 was supplemented with amino acids to match the essential amino acid pattern of the isolate to that of the flour in diet 1. Diet 3 was further supplemented with nonessential nitrogen in the form of ammonium citrate in order to bring the total nitrogen level of the diet up to that of diets 1 and 2, The following data was collected for each dietary treatment: 1} Urinary nitrogen excretion; 2) fecal nitrogen excretion; 3) nitrogen intake based on an analysis of actual food intake. After a 7-day adjustment period to allow subjects to adjust to the low nitrogen intake, nitrogen retention was calculated from data collected during a 5-day experimental period. Nitrogen retentions for the three groups were: flour, -0.06; isolate, -0.30; and supplemented isolate, -0.21 grams of nitrogen per person per day. Analyses of variance showed no treatment effects on urinary or fecal nitrogen excretion or nitrogen retention. It was concluded that, under the conditions of this experiment, soy flour and soy protein isolate are equally well utilized by the human adult. / Ph. D.

Fully cyclized, soluble phenylethynyl-terminated ether imide oligomers of 2.0-10.0 kg/mole (Mn) were prepared in high yield by the reaction of 2,2'-Bis[4-(3,4-dicarboxyphenoxy)phenyl]-propane dianhydride (Bisphenol- A Dianhydride, BPADA) with a stoichiometric excess of p-/m- phenylene diamine and phenylethynylphthalic anhydride (4-PEPA) endcapper. The lower (Mp) oligomers displayed attractive low melt viscosity properties, and were successfully processed via thermal curing at 350-380°C for 30-90 minutes. The 3.0 kg/mole oligomers had a cured glass transition temperature (Tg) of 267°C and produced tough, solvent-resistant films. Excellent adhesion values to surface treated titanium alloys were produced by single lap shear measurements. Resin infusion molding has been conducted that permitted low void graphite fabric composite panels to be prepared. The diamine monomer bis(m-aminophenyl) methyl phosphine oxide (DAMPO) was synthesized via nitration and the reduction of diphenyl methyl phosphine oxide. Rigorous purification of this monomer enabled it to be used for the synthesis of high molecular weight polyetherimides. Both thermoplastic materials and thermosetting systems endcapped with either phthalic or phenylethynylphthalic anhydride, respectively, have been produced. Major emphasis has been placed on polyimides derived from 2,2’- bis(4-(3,4-dicarboxyphenoxy) phenyl) propane dianhydride (BPADA). High molecular weight homo- and copolyimides based on BPADA/DAMPO exhibited glass transition temperature values in the range of 215-223°C, and were completely amorphous. They displayed higher modulus and tensile strength values than the polyetherimide control based on meta-phenylene diamine, and also generated high TGA char yields in air. Phenylethynyl crosslinkable materials were effectively cured at 380°C to produce solvent resistant networks that were ductile, and which also generated high char yields, suggesting their possible utilization in fire resistant matrix systems. / Ph. D.

This dissertation develops and applies new tools for distinguishing and disentangling high-frequency and low-frequency relationships among stationary economic time series. The new approach proposed here is a three-step procedure; the first step transforms the regression model in the time domain to a real-valued model in the frequency domain, which is functionally identical to an ordinary regression model, the only different being that "observations" of this model correspond to different frequencies rather than to different time periods. Consequently, in the second step, well established regression parameter stability tests are used to detect and assess the frequency dependence of relationships among economics time series. This new approach allows one to not only detect model misspecification of this type but also to correct it. In the third step, the results of the parameter stability across frequency tests is used to sensibly choose the best varying-parameter model in the frequency domain, which is then back-transformed to a time domain model and to be used for forecasting. The empirical example (using macroeconomic data) presented in this dissertation shows that the back-transformed model that allows varying parameter across frequencies significantly improves the forecasting performance of the misspecified fixed-parameter model. / Ph. D.

A human factors experiment was conducted to determine the effects of warning sound type, speaker location, and age on the ability to localize the direction of warning sounds in a passenger vehicle. The purpose of these warning sounds is to alert a driver of potential roadway hazards detected by an in-vehicle crash avoidance warning device. Auditory localization of the warning sound was investigated as a means of indicating hazard locations relative to the vehicle. Four dependent variables were measured— response time, decision time, accuracy, and azimuth—to assess the speed and accuracy of localizing six different warning sounds from each of sixteen speaker locations. The six warnings were found to be appropriate for crash avoidance warning applications through a previous study. The localization task was performed in the passenger compartment of a stationary 1995 Ford Taurus sedan. Subjects input their responses through a joystick. The results of the study suggest that the implementation of localized auditory crash avoidance warnings could be beneficial in the timely identification of hazard locations in the vehicle environment. People can quickly localize the general direction of warning sounds (= 1 s to 1.5 s); however, localization effectiveness depends on the proper choice of warning sound and speaker location. Otherwise, potentially serious problems can occur if poor choices are made. The study was successful in identifying sounds and speaker locations that performed best and provides recommendations for speaker placement for each of six potential hazard directions for the vehicle tested. / Master of Science

A direct liquid injection (DLI) metalorganic chemical vapor deposition (MOCVD) technique was devised to deposit ferroelectric lead zirconate titanate (PZT) films for the first time. By utilizing a cheap DLI precursor delivery system, the problems encountered in the conventional precursor delivery system by bubblers were eliminated. Highly uniform PZT films with a spatial variation in film composition of less than ± 3.0% were grown along a range of an 8 cm long substrate holder. The composition and thickness variation within 4 runs was less than ± 5% and ± 8%, respectively. The linear relationship between the composition in precursor solution and in PZT films makes the composition control very easy for the process of DLI-MOCVD preparation of PZT films. The growth temperature had the largest effect on various properties of deposited PZT films. PZT films with (111) orientation were easily deposited at a higher growth temperature while at a low growth temperature, PZT films with (001) orientation tended to form. The effect of annealing on the top electrodes was observed to have the hysterisis loop symmetric and to reduce the leakage current of PZT films. The present DLI-MOCVD grown PZT films showed good ferroelectric properties. Two-remanent polarization from 20 to 50 µC/cm² and two-coercive field from 60 to 100 Kv/cm can be easily obtained from these PZT films which have the thickness range from 300 nm to 1000 nm. The remanent polarization was affected by Lanthanum doping, which decreased from 25µC/cm² at 0% La doping to 12µC/cm² at 8% La doping. No obvious effects on the coercive field and the morphology were observed within these La doping ranges. The leakage current density of our PZT films was decreased as the growth temperature reduced. By reducing the growth temperature from 640°C to 590°C, the leakage current density was reduced one order of magnitude to 5 x 10⁻⁸ A/cm² at an electrical field of 100 Kv/cm. These films also showed high dielectric constants, about 700 for PLZT (4/34/66) and about 1200 for PLZT (4/55/45). The dissipation factors, tan 𝜕, for the above films were 0.023 and 0.03, respectively. The electrical fatigue of the typical PZT films showed 70% switched polarization remained after 10¹⁰ cycles. Surface etching by Ar ion bombardment and H-tetramethylheptadione or H(thd) was applied to get rid of possible PbO which is electrical conducting on the PZT films. No improvement on the leakage current of PZT films was observed. Lead excess from -25% to -10% in the precursor solution was found to produce the PZT films with the strongest (111) orientation and surface flatness. However the best electrical properties were only found in the lead concentration range of -10% to 10% in the precursor solution. PbO may not be the reason for the leakage current of the PZT films. Optical microscopy observation showed that gas phase reaction at higher growth temperature may be the reason for the leakage current of the PZT films. Both the leakage current and morphology were improved obviously by reducing the growth temperature. The non-homogeneous grains of the PZT films may be the other reason to lead the leakage current of our PZT films. Both stochiometry and non-stochiometry two-step-grown PZT films have shown significant improvement in the homogeneity of the grains of PZT films, which should have low leakage current. / Master of Science

The objectives of this dissertation are: (1) to examine the relationship between the accuracy and reliability of methods of estimating settlements of footings on sand and gravel, (2) to develop a procedure for estimating horizontal movements and rotations of footings without the need of determining soil modulus values, and (3) to develop a simple procedure for calculating movements of retaining walls due to the weight of backfill. The accuracy and reliability of twelve methods of estimating settlements of footings on sand and gravels were examined by comparing calculated settlements with the measured values. Eleven of the methods are based on Standard Penetration Test Results, while Schmertmann’s method is based on Cone Penetration Test Results. The study showed that methods which are more accurate tend to underestimate settlements about half of the time; while those which are more reliable (in the sense that they infrequently underestimate settlements) tend to be less accurate. The study also indicated that these methods of estimating settlements of footings on sands and gravels involve approximately the same relationship between accuracy and reliability, regardless of the approach that they use to calculate settlement. The results demonstrate that there is a tradeoff between accuracy and reliability. Any of the methods can be adjusted to achieve approximately the same combination of accuracy and reliability as other method. A simple procedure is presented to relate horizontal movements and rotations of footings to settlements. The procedure does not require the determination of soil modulus, and its accuracy and reliability can be assessed qualitatively by association with the method used to calculate the settlement. A simple procedure based on elastic theory was also developed to estimate movements of abutments and retaining walls due to the weight of backfill placed behind them. To avoid the inherent difficulty in determining the soil modulus, a procedure for relating these movements to the settlement of the wall was also developed. The new procedure was applied to a case history, and the calculated movements agree quite well with those calculated using the finite element method, and with field observations. / Ph. D.

I examine the firms with different hedging needs in their investment and financing strategy during the financial crisis in 2008. I define the hedging needs using the correlation between their cash flow and the industry Q. The firms with positive correlation between the cash flow and industry Q are defined as low hedging needs firms and the firms with negative correlation between the cash flow and industry Q are defined as high hedging needs firms. The low hedging needs firms have similar investment growth as high hedging needs firms before the crisis but significantly less investment growth during the crisis. However, the impact of financial crisis on firms with low hedging needs is smaller. Those firms efficiently respond to the decline of investment opportunity during crisis period by cutting capital expenditures since the capital expenditure in crisis are associated with lower profitability. And the empirical results support that there is a mix of supply shock and demand shock during financial crisis in 2008. / Tao, Xiaojue. / Thesis M.Phil. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 22-24). / Title from PDF title page (viewed on 11, October, 2016). / Tao, Xiaojue.

Open-source cloud platforms provide a feasible alternative of deploying cloud computing in low-cost commodity hardware and operating systems. To enhance the reliability of an open-source cloud, we design and implement CloudVS, a practical add-on system that enables version control for virtual machines (VMs). CloudVS targets a commodity cloud platform that has limited available resources. It exploits content similarities across different VM versions using redundancy elimination (RE), such that only non-redundant data chunks of a VM version are transmitted over the network and kept in persistent storage. Using RE as a building block, we propose a suite of performance adaptation mechanisms that make CloudVS amenable to different commodity settings. Specifically, we propose a tunable mechanism to balance the storage and disk seek overheads, as well as various I/O optimization techniques to minimize the interferences to other co-resident processes. We further exploit a higher degree of content similarity by applying RE to multiple VM images simultaneously, and support the copy-on-write image format. Using real-world VM snapshots, we experiment CloudVS in an open-source cloud testbed built on Eucalyptus. We demonstrate how CloudVS can be parameterized to balance the performance trade-offs between version control and normal VM operations. / 開源雲端平台為供低成本硬件及作業系統提供一個可行的替代方案。為了提高開源雲的可靠性，我們設計及實踐了CloudVS，一個針對虛擬機的實用版本控制系統。CloudVS針對有限資源的低成本硬件雲平台，利用內容相似性，在不同的虛擬機版本使用冗餘消除。這樣，在虛擬機版本數據中只有非冗餘的部分在網絡上傳輸，並保存在持久存儲。使用冗餘消除作為構建塊，我們提出了一套性能適應機制，使CloudVS適合於不同的低成本硬件配置。具體而言，我們提出了一種可調諧的機制來平衡存儲和磁盤尋道開銷，以及應用各種I/O優化技術去最大限度地減少對其他同時運行進程的干擾。我們應用冗餘消除多個虛擬機影像去進一步利用其內容相似度，同時，我們更進一步支持寫時複製格式。使用來自真實世界的虛擬機快照，我們嘗試在開放源碼的雲測試平台Eucalyptus中測試CloudVS。我們演示CloudVS如何可以參數化，以平衡版本控制和正常的虛擬機操作之間的性能取捨。 / Tang, Chung Pan. / Thesis M.Phil. Chinese University of Hong Kong 2013. / Includes bibliographical references (leaves 57-65). / Abstracts also in Chinese. / Title from PDF title page (viewed on 07, October, 2016). / Detailed summary in vernacular field only.

People are increasingly recognizing how their health affects their quality of life, and health is most easily tracked through the use of wearable devices. The goal of this study is to detect and monitor human motion via gait analysis to provide information that will help people enhance their health. After reviewing a range of wearable health-tracking devices, the shoe has been chosen as one of the best device for observing human motion. / Most measurement systems currently used for motion and gait detection are disadvantaged in that they monitor and analyze motion in limited environments and not in real time. Hence, they cannot be used for long-term monitoring and detection. The design of a new, inexpensive, compact and lightweight shoe-integrated platform is elaborated in this thesis. The intelligent shoe system comprises a suite of sensors, a microprocessor board and a wireless communication module. This ideal platform requires no specialized equipment or lab setup, meaning data can be collected not only in the narrow confines of a research lab, but essentially anywhere, whether indoors or outdoors. / Our everyday lives are shaped by a wide variety of motions, some of which can cause injury. Injuries suffered due to falls account for a significant portion of accidents and immediate help should be provided. The intelligent shoe system offers an approach of detecting the user’s motion, especially the movement and direction of a fall. This study used principle component analysis (PCA) to decrease the number of sensors in the prototype (eight pairs) by half (four pairs), so as to reduce computational cost and enhance real-time performance. The resultant system can learn the patterns necessary to detect fall directions from abundant tilted-standing data instead of actual fall data. / Fatigue can result in an abnormal gait, making injury more probable. Hence, detecting fatigue is very important. Experiments have been conducted to determine the relationship between fatigue and gait, and the resultant data are used to analyze the relationship between force information and foot attitude. These findings can help a user detect fatigue and avoid injury. / People carry various kinds of loads in their daily lives, and long-term load-bearing activities can result in motion deformation. Another objective of this study is to determine a load-carrying approach that will decrease such deformation to a great extent. Resampling is used to partition the related data cycle by cycle. A support vector machine (SVM) is adopted to model a user’s normal walking gait and abnormal gaits without loads, which allows for the determination of whether a gait is normal when a load is carried. / To enhance overall health, exercise is commonly adopted, but many forms of exercise are dull. The proposed system’s shoe-computer interface not only helps people obtain detailed lower-body feedback, but can also be used to promote everyday exercise. People are analyzed while sitting for long periods in the workplace, and two interfaces are designed as a result: the shoe-keyboard, in which the feet are used to type words into a computer, and the shoe-write system, in which the foot is used like a hand to write on the ground, with the words displayed on the computer screen. Both of these applications use back-propagation (BP) networks to classify the motions involved. The shoe-keyboard is based on logical coding to map the motion-to-word relationship, and the shoe-write system incorporates an optical tracker to translate motion into information. / 人們現在越來越重視自己的生活質量，而健康方面是最為重要的。穿戴式設備是最好容易使用的檢測健康的設備。本文的目標是通過智能鞋，來檢測步態，對其進行分析和預測，已達到檢測和提高人們的健康水平的要求。 / 現在絕大多數的步態運動檢測系統都不是實時的且長時間工作的。在研究中，基於鞋子的智能系統被提出并得以實現，其具有便宜，緊湊，輕便等的優點。該系統包括壓力和加速度傳感器，處理芯片和無線傳輸模塊。這種設計將滿足日常步態信息的採集，并且把環境影響的因素放置最小，以達到室內室外都可長時間連續實時監測的要求。 / 在本論文中，對一系列日常生活的行為進行檢測和分類，尤其是最為危險的摔倒。本系統通過採用主成分分析，對已有的壓力傳感器進行的了分析，在保證了預測的準確性的前提下，將壓力傳感器由8對減少至4對，大大的降低了運算的次數，使得該系統實時性更好。同時本系統通過傾斜站立獲得的數據并應用于跌倒方向的檢測，並且有著良好的結果。 / 在本文中，對疲勞步態進行的分析，通過設計實驗，來區分不同疲勞程度下人們的步態。壓力信號較為明顯，同時加速度反映出每一步的劇烈程度。最終結果表明，壓力和加速度相輔相成，與疲勞程度的關係也很明顯，基於這種關係，本系統對疲勞程度進行了預測，通過壓力傳感器的信號，預測疲勞的程度，實驗結果也較為理想。 / 長時間的負責對身體的負擔很大，在本文中，著重的分析了在不同負重方式下，步態的變化，並且通過對比正常步態，採用支持向量機進行分類。在分類的過程中，通過重新採樣，將採集的數據轉變為一步為一組的數據，進行分類，最終得到的結果表明，平衡狀態下的負重是最好的。 / 對於健康而言，除了檢查受傷和疲勞，提升自身的身體素質也尤為重要。在本文中，介紹了兩種基於智能鞋的應用，在鍛煉下肢靈活度的同時，也避免了鍛煉的無聊。智能鞋鍵盤是通過腳踝的運動，基於一定的編碼方式，已達到在電腦上輸入文字的方式。智能鞋寫字系統是通過對下腳點的定位結合光電傳感器記錄位移，最終獲得文字輸入。應用BP神經網絡，對腳下點進行了分類，結合壓力傳感器和腿部建模，可以準確的區分30個的基本點的位置，從而獲得每筆的起點。最終完成寫字輸入。 / Tao, Yanbo. / Thesis Ph.D. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 134-141). / Abstracts also in Chinese. / Title from PDF title page (viewed on 12, October, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.