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In telecommunication, the series of mobile network exceptions is a processwhich exhibits surges and bursts. The bursty part is usually caused by systemmalfunction. Additionally, the mobile network exceptions are often timedependent. A model that successfully captures these aspects will make troubleshootingmuch easier for system engineers. The Hidden Markov Model(HMM) is a good candidate as it provides a mechanism to capture both thetime dependency and the random occurrence of bursts. This thesis focuses onan application of the HMM to mobile network exceptions, with a case study ofEricsson’s Dropped Call data. For estimation purposes, two methods of maximumlikelihood estimation for HMM, namely, EM algorithm and stochasticEM algorithm, are used.

This thesis is on quantum algorithms. It has three main themes: (1) quantum walk based search algorithms, (2) quantum rejection sampling, and (3) the Boolean function hidden shift problem. The first two parts deal with generic techniques for constructing quantum algorithms, and the last part is on quantum algorithms for a specific algebraic problem. In the first part of this thesis we show how certain types of random walk search algorithms can be transformed into quantum algorithms that search quadratically faster. More formally, given a random walk on a graph with an unknown set of marked vertices, we construct a quantum walk that finds a marked vertex in a number of steps that is quadratically smaller than the hitting time of the random walk. The main idea of our approach is to interpolate the random walk from one that does not stop when a marked vertex is found to one that stops. The quantum equivalent of this procedure drives the initial superposition over all vertices to a superposition over marked vertices. We present an adiabatic as well as a circuit version of our algorithm, and apply it to the spatial search problem on the 2D grid. In the second part we study a quantum version of the problem of resampling one probability distribution to another. More formally, given query access to a black box that produces a coherent superposition of unknown quantum states with given amplitudes, the problem is to prepare a coherent superposition of the same states with different specified amplitudes. Our main result is a tight characterization of the number of queries needed for this transformation. By utilizing the symmetries of the problem, we prove a lower bound using a hybrid argument and semidefinite programming. For the matching upper bound we construct a quantum algorithm that generalizes the rejection sampling method first formalized by von~Neumann in~1951. We describe quantum algorithms for the linear equations problem and quantum Metropolis sampling as applications of quantum rejection sampling. In the third part we consider a hidden shift problem for Boolean functions: given oracle access to f(x+s), where f(x) is a known Boolean function, determine the hidden shift s. We construct quantum algorithms for this problem using the "pretty good measurement" and quantum rejection sampling. Both algorithms use the Fourier transform and their complexity can be expressed in terms of the Fourier spectrum of f (in particular, in the second case it relates to "water-filling" of the spectrum). We also construct algorithms for variations of this problem where the task is to verify a given shift or extract only a single bit of information about it.

The chief focus of this study was on unearthing the antecedents of resilience in children on the street and street children in institutional care. This study was motivated by the desire to understand what made some street children function resiliently in spite of the individual, familial, environmental and wider community risk process that threaten resilience. I was alerted to the participants' resilience by the unexpected positive findings after they completed the Child and Youth Resilience Measure (CYRM). Twenty street children volunteered to take part in this study. Of the 20 participants who took part in this study, 14 were children on the street who still had contact with families and six resided at a shelter with no regular contact with their families. This was a mixed methods exploratory study in which I employed the Child and Youth resilience Measure (CYRM) to collect quantitative data from all the participants, and qualitative data via individual interviews and a focus group interview. I used the interviews to provide a deeper understanding of the antecedents of resilience identified in the CYRM. My findings from this study documented individual and environmental resilience processes that enabled the participants to function resiliently despite the harshness of streetism. Many of the resilience -promoting resources unearthed have not been linked to street children and previous studies on resilient street children have not noted all inter- and intrapersonal resources identified by the street children in my study. These resources included individual resources such as role models, assertiveness, regulating themselves socially, coping mechanisms, community - based resources such as access to education as well as cultural resources which include cultural groundedness and religion. These findings show that some street children are resilient and that they develop coping mechanisms reminiscent of hidden resilience that enable them to cope with streetism. The findings of this study have implications for practice especially asset-focused approaches to supporting street children. / Thesis (Ph.D. (Education))--North-West University, Vaal Triangle Campus, 2009.

The chief focus of this study was on unearthing the antecedents of resilience in children on the street and street children in institutional care. This study was motivated by the desire to understand what made some street children function resiliently in spite of the individual, familial, environmental and wider community risk process that threaten resilience. I was alerted to the participants' resilience by the unexpected positive findings after they completed the Child and Youth Resilience Measure (CYRM). Twenty street children volunteered to take part in this study. Of the 20 participants who took part in this study, 14 were children on the street who still had contact with families and six resided at a shelter with no regular contact with their families. This was a mixed methods exploratory study in which I employed the Child and Youth resilience Measure (CYRM) to collect quantitative data from all the participants, and qualitative data via individual interviews and a focus group interview. I used the interviews to provide a deeper understanding of the antecedents of resilience identified in the CYRM. My findings from this study documented individual and environmental resilience processes that enabled the participants to function resiliently despite the harshness of streetism. Many of the resilience -promoting resources unearthed have not been linked to street children and previous studies on resilient street children have not noted all inter- and intrapersonal resources identified by the street children in my study. These resources included individual resources such as role models, assertiveness, regulating themselves socially, coping mechanisms, community - based resources such as access to education as well as cultural resources which include cultural groundedness and religion. These findings show that some street children are resilient and that they develop coping mechanisms reminiscent of hidden resilience that enable them to cope with streetism. The findings of this study have implications for practice especially asset-focused approaches to supporting street children. / Thesis (Ph.D. (Education))--North-West University, Vaal Triangle Campus, 2009.

Although the significance of education is widely recognized, the content and regimentation of education is not often discussed in contemporary Japan. This thesis analyzed the Japanese education system from Meiji Restoration to today, revealing how the Japanese education system has molded citizens in favor of state power. The persistent system, which has produced citizen conformity, eventually created mindless self-censored citizens. As a result, because of the repeated education dogma, Japanese youths are desperately trying to be ideal Japanese citizens. Nevertheless, the ramifications of the education system in Japanese society, have led to the Hikikomori (or hidden youths) and high suicide rates. The findings of this thesis are based on the education guidelines from the Japanese education ministry and from interviews with various Japanese people. The conclusion is that if the Japanese education system keeps ousting the freedoms of students, the system may once again have a devastating effect on democracy as was seen in Japan in the 1930s. / Graduate

The maintenance of equipment has been an important issue for companies for many years. For systems with hidden or unrevealed failures (i.e., failures are not self-announcing), a common practice is to regularly inspect the system looking for such failures. Examples of these systems include protective devices, emergency devices, standby units, underwater devices etc. If no periodical inspection is scheduled, and a hidden failure has already occurred, severe consequences may result. Research on periodical inspection seeks to establish the optimal inspection interval (Failure Finding Interval) of systems to maximize availability and/or minimize expected cost. Research also focuses on important system parameters such as unavailability. Most research in this area considers non-negligible downtime due to repair/replacement but ignores the downtime caused by inspections. In many situations, however, inspection time is non-negligible. We address this gap by proposing an optimal failure finding interval (FFI) considering both non-negligible inspection time and repair/replacement time. A novel feature of this work is the development of models for both age-based and calendar-based inspection policies with random/constant inspection time and random/constant repair/replacement time. More specifically, we first study instantaneous availability for constant inspection and repair/replacement times. We start with the assumption of renewal of the system at each inspection. We then consider models with the assumption of renewal only after failure. We also develop limiting average availability models for random inspection and repair/replacement times, considering both age-based and calendar-based inspection policies. We optimize these availability models to obtain an optimal FFI in order to maximize the system’s availability. Finally, we develop several cost models for both age-based and calendar-based inspection policies with random inspection time and repair/replacement time. We formulate the model for constant inspection time and repair/replacement time as a special case. We investigate the optimization of cost models for each case to obtain optimal FFI in order to minimize the expected cost. The numerical examples and case study presented in the dissertation demonstrate the importance of considering non-negligible downtime due to inspection.

The maintenance of equipment has been an important issue for companies for many years. For systems with hidden or unrevealed failures (i.e., failures are not self-announcing), a common practice is to regularly inspect the system looking for such failures. Examples of these systems include protective devices, emergency devices, standby units, underwater devices etc. If no periodical inspection is scheduled, and a hidden failure has already occurred, severe consequences may result. Research on periodical inspection seeks to establish the optimal inspection interval (Failure Finding Interval) of systems to maximize availability and/or minimize expected cost. Research also focuses on important system parameters such as unavailability. Most research in this area considers non-negligible downtime due to repair/replacement but ignores the downtime caused by inspections. In many situations, however, inspection time is non-negligible. We address this gap by proposing an optimal failure finding interval (FFI) considering both non-negligible inspection time and repair/replacement time. A novel feature of this work is the development of models for both age-based and calendar-based inspection policies with random/constant inspection time and random/constant repair/replacement time. More specifically, we first study instantaneous availability for constant inspection and repair/replacement times. We start with the assumption of renewal of the system at each inspection. We then consider models with the assumption of renewal only after failure. We also develop limiting average availability models for random inspection and repair/replacement times, considering both age-based and calendar-based inspection policies. We optimize these availability models to obtain an optimal FFI in order to maximize the system’s availability. Finally, we develop several cost models for both age-based and calendar-based inspection policies with random inspection time and repair/replacement time. We formulate the model for constant inspection time and repair/replacement time as a special case. We investigate the optimization of cost models for each case to obtain optimal FFI in order to minimize the expected cost. The numerical examples and case study presented in the dissertation demonstrate the importance of considering non-negligible downtime due to inspection.

This thesis deals with scene level summarization of story-based videos. Two different approaches for story-based video summarization are investigated. The first approach probabilistically models the input video and identifies scene boundaries using the same model. The second approach models scenes and classifies scene types by evaluating likelihood values of these models. In both approaches, hidden Markov models are used as the probabilistic modeling tools. The first approach also exploits the relationship between video summarization and video production, which is briefly explained, by means of content types. Two content types are defined, dialog driven and action driven content, and the need to define such content types is emonstrated by simulations. Different content types use different hidden Markov models and features. The selected model segments input video as a whole. The second approach models scene types. Two types, dialog scene and action scene, are defined with different features and models. The system classifies fixed sized partitions of the video as either of the two scene types, and segments partitions separately according to their scene types. Performance of these two systems are compared against a iv deterministic video summarization method employing clustering based on visual properties and video structure related rules. Hidden Markov model based video summarization using content types enjoys the highest performance.