In this study, a novel counter-cross-flow run-around membrane energy exchanger (RAMEE) system was designed and tested in the laboratory. The RAMEE system consists of two (2) counter-cross-flow Liquid-to-Air Membrane Energy Exchangers (LAMEEs) to be located in the supply and exhaust air streams in the building Heating Ventilation and Air-Conditioning (HVAC) system. Inside each exchanger, a micro-porous membrane separates the air and liquid streams and allows transfer of the sensible and latent energy from the air stream to the liquid stream or vice-versa. The system exchanges sensible and latent energy between supply and exhaust air streams using a desiccant solution loop. The supply and exhaust air streams in the RAMEE can be located far apart from each other or adjacent to each other. The flexibility of non-adjacent ducting makes the RAMEE system a better alternative compared to available energy recovery systems for the retrofit of HVAC systems.<p> Two counter-cross-flow exchangers for the RAMEE system were designed based on an industry recommended standard which is to obtain a target overall system effectiveness of 65% for the RAMEE system at a face velocity of 2 m/s. The exchanger design was based on heat exchanger theory and counter-cross-flow design approach. An exchanger membrane surface aspect ratio (ratio of exchanger membrane surface height to exchanger length) of 1/9 and the desiccant solution entrance ratio (ratio of desiccant solution entrance length to exchanger length) of 1/24 were employed. Based on different heat transfer case studies, the energy transfer size of each exchanger was determined as 1800 mm x 200 mm x 86 mm. ProporeTM was used as the membrane material and Magnesium-Chloride solution was employed as the desiccant solution.<p> The RAMEE performance (sensible, latent and total effectiveness) was evaluated by testing the system in a run-around membrane energy exchanger test apparatus by varying the air stream and liquid solution-flow rates at standard summer and winter operating conditions. From the test data, the RAMEE effectiveness values were found to be sensitive to the air and solution flow rates. Maximum total effectiveness of 45% (summer condition) and 50% (winter condition) were measured at a face velocity ¡Ö 2 m/s. A comparison between the experimental and numerical results from the literature showed an average absolute discrepancy of 3% to 8% for the overall total system effectiveness. At a low number of heat transfer units, i.e. NTU = 4, the numerical and experimental results show agreement within 3% and at NTU = 12 the experimental data were 8% lower than the simulations. The counter-cross-flow RAMEE total system effectiveness were found to be 10% to 20% higher than those reported for a cross-flow RAMEE system by another researcher.<p> It is thought that discrepancies between experimental and predicted results (design and numerical effectiveness) may be due to the mal-distributed desiccant solution-flow, desiccant solution leakage, lower than expected water vapor permeability of the membrane, uncertainties in membrane properties (thickness and water vapor permeability) and heat loss/gain effects. Future research is needed to determine the exact cause of the discrepancies.

The principal focus of this thesis is the exploration of sparse structures in a variety of statistical modelling problems. While more comprehensive models can be useful to solve a larger number of problems, its calculation may be ill-posed in most practical instances because of the sparsity of informative features in the data. If this sparse structure can be exploited, the models can often be solved very efficiently. The thesis is composed of four projects. Firstly, feature sparsity is incorporated to improve the performance of support vector machines when there are a lot of noise features present. The second project is about an empirical study on how to construct an optimal cascade structure. The third project involves the design of a progressive, rate-distortionoptimized shape coder by combining zero-tree algorithm with beamlet structure. Finally, the longest run statistics is applied for the detection of a filamentary structure in twodimensional rectangular region. The fundamental ideas of the above projects are common — extract an efficient summary from a large amount of data. The main contributions of this work are to develop and implement novel techniques for the efficient solutions of several dicult problems that arise in statistical signal/image processing.

Computing the similarity of two strings or sequences is one of the most important fundamental in computer field, and it has been widely studied for several decades. In the last decade, it gained the researchers' attentions again because of the improvements of the hardware computation ability and the presence of huge amount of data in biotechnology. In this dissertation, we pay attention to computing the edit distance between two sequences where the block-edit operations are involved in addition to the character-edit operations. Previous researches show that this problem is NP-hard if recursive block moves are allowed. Since we are interested in solving the editing problems by the polynomial-time optimization algorithms, we consider the simplified version of the edit distance problem. We first focus on the longest common subsequence (LCS) of run-length encoded (RLE) strings, where the runs can be seen as a class of simplified blocks. Then, we apply constraints to the problem, i.e. to find the constrained LCS (CLCS) of RLE strings. Besides, we show that the problems which involve block-edit operations can still be solved by the polynomial-time optimization algorithms if some restrictions are applied. Let X and Y be two sequences of lengths n and m, respectively. Also, let N and M, be the numbers of runs in the corresponding RLE forms of X and Y, respectively. In this dissertation, first, we propose a simple algorithm for computing the LCS of X and Y in O(NM + min{ p_1, p_2 }) time, where p_1 and p_2 denote the numbers of elements in the bottom and right boundaries of the matched blocks, respectively. This new algorithm improves the previously known time bound O(min{nM, Nm}) and outperforms the time bounds O(NM log NM) or O((N+M+q) log (N+M+q)) for some cases, where q denotes the number of matched blocks. Next, we give an efficient algorithm for solving the CLCS problem, which is to find a common subsequences Z of X and Y such that a given constrained sequence P is a subsequence of Z and the length of Z is maximized. Suppose X, Y and P are all in RLE format, and the lengths of X, Y and P are n, m and r, respectively. Let N, M and R be the numbers of runs in X, Y, and P, respectively. We show that by RLE, the CLCS problem can be solved in O(NMr + min{q_1 r + q_4, q_2 r + q_5 }) time, where q_1 and q_2 denote the numbers of elements in the south and east boundaries of the partially matched blocks on the first layer, respectively, and q_4 and q_5 denote the numbers of elements of the west and north pillars in the bottom boundaries of all fully matched cuboids in the DP lattice, respectively. When the input strings have good compression ratios, our work obviously outperforms the previously known DP algorithms and the Hunt-Szymanski-like algorithms. Finally, we consider variations of the block edit distance problem that involve character insertions, character deletions, block copies and block deletions, for two given sequences X and Y. In this dissertation, three variations are defined with different measuring functions, which are P(EIS, C), P(EI, L) and P(EI, N). Then we show that with some preprocessing, the minimum block edit distances of these three variations can be obtained by dynamic programming in O(nm), O(nm log m) and O(nm^2) time, respectively, where n and m are the lengths of X and Y.

No description available.

In this work, a method to choose the best run order for a given experimental design is proposed, for the simple linear regression model with MA errors. More specifically we investigate the best run order of an uniform design when errors follow a MA(1) or a subset MA(k) process where k is a positive integer. The correlation matrix P resulting from the errors is usually difficult to obtain a good estimate. Using the change of variance function(CVF) to see the relation of the uncorrelated and the serially correlated errors. Criterion proposed by Zhou (2001), we find the best run order of the uniform design on [-1,1] to minimize the robust criterion, |CVF|. We will display the permutation of a run order after rearrangement by our method and show how the structure is decomposed into three categories to solve the problem.

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Waterhammer is an unsteady hydraulic problem which is commonly found in closed conduits of hydropower plants, water distribution networks and liquid pipeline systems. Due to either a malfunction of the system or inadequate operation conditions, pipeline may collapse or burst erratically resulting in substantial damages, and human losses in some cases. In this thesis, time dependent flow situations in the penstocks of small hydropower plants are investigated. A software, HAMMER, that utilizes method of characteristics for solving nonlinear differential equations of transient flow is used in the study. In two case studies, various operation conditions such as load rejection, load acceptance and instant load rejection are studied. The parameters and situations affecting pressure and turbine speed rises are investigated. Computed and available measured values are found to be very close. Also, differences between waterhammer responses of the Francis and Pelton turbines are revealed. Finally, specific protective measures are suggested to either diminish and/or avoid the harmful effects of waterhammer problems in small hydropower plants.

Run-of-river type hydroelectrical power plants are the facilities that use only the available flow on the river without storing it to generate electrical energy. These kind of facilities are composed of structural components such as diversion weir, conveyance line, forebay, penstock and power house. In this thesis, a computer program called &ldquo / MiniHEPP Hydraulic Design&rdquo / is developed in order to perform the hydraulic design of run-of-river type hydropower plants. This program which runs under the Windows operating system, was developed in C# programming language. MiniHEPP Hydraulic Design is capable of performing hydraulic design of structural components of diversion weir with sidewise intake and overflow spillway, canal, forebay, and penstock. In addition, it can determine the optimum design discharge and penstock diameter of this type of hydropower plants.

Extant literature finds that long-term abnormal stock returns are generated by a strategy based on corporate governance index values (Gompers, Ishii, and Metrick 2003). The result is inconsistent with efficient markets and suggests that information about governance is not accurately reflected in market data. Control firm portfolios are used to mitigate model misspecification in measuring long-term abnormal returns. Using a number of different matching criteria and governance indices, no long-term abnormal returns are found to trading strategies based on corporate governance. The effect of a change in governance on firm value is mixed, but some support is found for poor governance destroying firm value. These results have a number of implications for practitioners, researchers, and policy makers.

In my dissertation, I explore the relationship between capital controls and the choice of the maturity structure of external debt in a general equilibrium setup, incorporating explicitly the role of international lenders. I look at specific types of capital controls which take the form of date-specific and maturity-specific reserve requirements on external borrowing. I consider two questions: How is the maturity structure of external debt determined in a world general equilibrium? What are the effects of date- and maturity-specific reserve requirements on the maturity structure of external debt? Can they prevent a bank run? I develop a simple Diamond-Dybvig-type model with three dates. In the low income countries, banks arise endogenously. There are two short-term bonds and one long-term bond offered by the domestic banks to international lenders. First I look at a simple model were international lending is modeled exogenously. I consider explicitly the maturity composition of capital inflows to a domestic economy. I show that the holdings of both short-term bonds are not differentiated according to date. Second, I consider international lending behavior explicitly. The world consists of two large open economies: one with high income and one with low income. The high income countries lend to low income countries. There exist multiple equilibria and some are characterized by relative price indeterminacy. Third, I discuss date-specific and maturity- specific reserve requirements. In my setup reserve requirements play the role of a tax and the role of providing liquidity for each bond at different dates. I show that they reduce the scope of indeterminacy. In some equilibria, I identify a case in which the reserve requirement rate on the long-term debt must be higher than that on the short-term debt for a tilt towards a longer maturity structure. Fourth, I introduce the possibility of an unexpected bank run. I show that some specific combination of date-and maturity-specific reserve requirements reduce the vulnerability to bank runs. With regard to the post-bank-run role of international lenders, I show that international lenders may still want to provide new short-term lending to the bank after the occurrence of a bank run.