VictorJuiz/thesis huggingface dataset:
Generalized singularity analysis of mechanisms

This thesis investigates a general class of mechanism configurations, usually referred to as kinematic singularities. The study of such configurations is of major practical and theoretical importance. Indeed, the kinematic properties of mechanisms change significantly in a singular configuration, and these changes can prove to be either beneficial or undesirable for different applications. On the other hand, the theoretic significance of singularities in mechanism theory is well-known and related to the fact that singular points play a prominent role in the theory of differentiable mappings. The central objective of this dissertation is to address the problems of mechanism singularity in a most general setting, namely, to consider arbitrary singular configurations of both non-redundant and redundant mechanisms with arbitrary kinematic chains, with a special emphasis on the study of mechanical devices with complex kinematic chains and non-serial, high-degree-of-freedom architectures. To this goal, a rigorous general mathematical definition of kinematic singularity for arbitrary mechanisms is introduced. This is achieved by means of a mathematical model of mechanism kinematics formulated in terms of differentiable mappings between manifolds. When the mathematical model is applied to the relationship between the joint and output velocities, a new unifying framework for the interpretation and classification of mechanism singularities is obtained. This framework, based on the newly introduced six singularity types, is applicable to arbitrary non-redundant as well as redundant mechanisms. Mathematical tools, such as singularity criteria and identification methods, are developed for the study of the singularity sets of both non-redundant and redundant systems with lower kinematic pairs.
Time-delayed control of flexible space structures

Time delays can be introduced inadvertently into flexible spacecraft control loops by computer processing delays or through direct ground control. They can adversely affect control system performance, leading at worst to instability. Their effect on the performance, or even the stability, of such closed-loop control systems is especially important for lightly damped vibratory systems. The stability boundaries of time-delayed rate and proportional feedback control of a lightly-damped single-degree-of-freedom harmonic oscillator are derived. Using a discrete-time system approximation, the stability analysis can be extended to more complicated systems. An experimental investigation of time delayed control is performed using the Daisy facility, a large space structures emulator. Limit cycles are found in the closed-loop experimental results for relatively modest time delays and instability is seen for time delays not much larger. Characterization of the free decay response of the Daisy facility produces a correlation between the magnitude of these limit cycles and the amount of actuator misalignment. Through simulations, it is found that the combination of time delay, sensor and actuator quantization, actuator dynamics, and actuator misalignment can produce limit cycle responses similar to those found experimentally.
Development of a structured approach for patient monitoring in the operating room

Patient monitoring in the operating room has become a topic of concern in recent years, in part because of the proliferation of technological devices of increasing complexity in the clinical work environment. Consequently, an increase in the cognitive demands of medical personnel is expected, potentially resulting in decreased clinical performance and increased patient risk. This thesis focused on structuring the work domain of the anaesthesiologist in the operating room, with the ultimate goal of defining the requirements for effective monitoring systems. Data were collected from literature reviews, discussions with anaesthesiologists, and operating room and simulator session observations. From this information, the work domain was structured and analyzed using various levels of abstraction and decomposition. The results indicated that this approach may be useful for interface design and training, because it provided a unified framework for representing the system as an invariant purpose-based structure for a constantly changing work environment.
Performance profile of children with learning disabilities and sensory integration dysfunction, an underlying constructional abilities deficit

There is a lack of specificity in describing the relationship between sensory integration deficits (SI) and learning disabilities (LD). A sample of children with both LD and SI dysfunction were divided into a low constructional abilities (LCA) group and a normal constructional abilities (NCA) group as measured by the Developmental Test of Visual Motor Integration (Beery, 1982) in order to determine if constructional deficits might identify a distinct profile in this population. The results showed that the NCA group performed better than the LCA group on measures of motor skill, attention, handwriting readiness, arithmetic and spelling readiness and sensory integrative functioning involving somatosensory and motor planning abilities. There were no group differences in visual-perception or language. The identification of different profiles among the groups suggests that a deficit in constructional abilities may be a distinguishing factor in characterizing the different strengths and weaknesses among children with LD and SI dysfunction.
Growing up happy, Aristotle's theory of moral education

My thesis examines Aristotle's ethics, focusing on his theory of moral education and how it is influenced by his conception of moral excellence. Moral excellence is complex and requires that the parts of the soul be in good condition and in the right relation to each other. The excellent person achieves harmony of thought and desire, which enables him to act consistently for the sake of the noble. Aristotle's model of the acquisition of moral excellence is a developmental one in which the student gradually progresses toward excellence. The child is naturally oriented toward excellence, but his natural capacities must be guided by society and family in order for excellence to be achieved. Aristotle's views on the child's nature and development make nature, habit and teaching all necessary parts of the educational process. In my dissertation, I stress the importance of Aristotle's teleology and concept of nature for his program of moral education, the influence of family and the 'polis ' on the child's development, and the interdependence of character and intellectual development. Moral education occurs in two stages: initial habituation, which is found in the process of education discussed in the 'Politics', and final habituation, which is found in the lessons contained in the ethical works. The first stage of education exhibits a certain naturalness and relies on a positive starting point and a good social context. The educator uses the child's impulses toward pleasure and honor and his relationships with family and friends to guide development. Several types of instruction are employed during initial habituation, including musical training, play, imitation, tragedy and repetition of actions. Moral education requires intellectual training as well as habituation. In addition to helping him to acquire 'phronesis', philosophical justification of the nature of the best life (of the sort found in the ethical works) motivates the student to try to achieve excellence and helps him to perform those acts which will bring the non-rational part of his soul into good condition. This knowledge unifies the student's desires and enables him to consistently choose noble acts, to perform his function and to achieve moral excellence.
Exemplary mathematics teachers, subject conceptions and instructional practices

Theoretical links between conceptions of mathematics and teaching practice have been postulated and research exploring these conjectures has been conducted at the elementary school level and to a limited extent with selected secondary school mathematics topics. Studies have shown that instrumentalist images of mathematics are carried into transmissive modes of instruction, but the few teachers with social constructivist views have troubles bringing their visions to practice. This study involving two exemplary secondary school mathematics teachers, that is teachers who are working to implement mathematics education reform, extends this line of research, exploring: their conceptions of mathematics, teaching practices, and the struggles they experience in bringing subject images to the classroom. Qualitative methods were used to explore conceptions of mathematics and teaching practice. The teachers' subject images were examined through personal writing on the nature of mathematics, repertory grid technique, and the construction of concept maps, and interviews analysing these products. Participant observation was employed to gather data on mathematics teaching and lessons were analysed from a sociological and epistemological perspective. In two case studies, using alternating sections presenting subject image themes and narratives of related teaching, links are built between practice and epistemology. In this study, one teacher with a well developed social constructivist image of mathematics managed to struggle against pupil and administrative opposition and put his personal subject philosophy into practice. The second teacher, with a more mixed subject conception, one that was undergoing transition and reconstruction, had difficulties translating his epistemology into practice and when confronted with opposition turned to traditional transmissive modes of instruction. His emerging constructivist views showed through in activities provided beyond the core of his lessons. Obstacles that the two teachers faced in attempting to implement their personal philosophies are examined and sources of support are identified. For both teachers, links to university faculty that provided opportunities for mathematical explorations beyond the school curriculum were valuable. The development of the stronger teacher's more complete and consistent image was helped by a professional network that provided opportunities for discussion of philosophical matters.
Topographic regulation of nitrate-N export from catchments within an old-growth sugar maple forest in the Turkey Lakes Watershed, central Ontario, Canada

Nitrogen (N) saturation of Canada's forests is a potentially serious threat to the health and integrity of forested landscapes. To develop policies to protect our forests, policy-makers require from scientists a diagnosis of a forest's N saturation status for representative regions along N deposition gradients. A promising tool to assist in the diagnosis of N saturation lies in the catchment N export behavior. This tool assumes that the N deposition history is the causal factor for the N export behavior and that the behavior from a catchment can therefore be scaled to the region. The dissertation tests this assumption by establishing the natural variations in N export behavior among catchments within a region and by exploring the process controls that lead to these variations. Within the test region, the Turkey Lakes Watershed located in central Ontario, the range in catchment-specific export was ±25% the catchment-average export for dissolved organic N and ±50% for dissolved inorganic N, indicating substantial natural variations in N export. The dissertation hypothesized that topography controlled the N export behavior. Empirical analyses of the concentrations of N in discharge waters suggested that for nitrate-N, the dominant N species, export was regulated by a topographically-regulated flushing mechanism and that the range in flushing activities among the catchments was a significant contributor to the variations in the N export behavior. A hybrid modeling approach was adopted in which the processes identified in the empirical analysis as regulating N export behavior were simulated and correlated with observed N export behavior. Using the model, although two mechanisms for producing significant concentrations of nitrate-N in discharge waters became evident, a rapid flushing and a slow draining of N, flushing was clearly the dominant mechanism. The simulation analyses emphasized that for scientists to predict accurately the N export behavior, topographic influences on the interactive impacts of N formation and flushing activities must be considered. The implications of these research findings are that N export behavior is tightly linked with topography and that within any given regional context, topographic complexity may take precedent over the landscape or regional controls on nitrate-N export behavior.
Performance analysis of Ontario credit unions

The theoretical contributions of this work to DEA science includes the development of an algorithm to find 'all' the facets of a VRS DEA frontier. This enables the projection of inefficient units to the closest point on the efficient frontier, or with the 'minimum' sum of slacks. The proportion of full dimensional facets affects the degree of freedom for movement along the frontier. The dimensionality of any region of the frontier can be determined and is discussed. An efficiency measure is introduced for inefficient units, relative to their closest point on the frontier. This efficiency measure can also be used with any projection to the frontier, including the traditional input or output oriented radial projections. With radial projections, slack is accounted for in this measure, and the measure collapses to the traditional radial measures when there is no slack. The practical application part of this work is based on data from Credit Unions in Ontario. This is an important sector of the Financial Services Industry, with 1996 assets of $13.5 billion and 1.7 million members. The health of the Credit Union industry is monitored by a government agency, the Deposit Insurance Corporation of Ontario (DICO), the collaborating entity that provided data for this research. In this section DEA models are developed to detect weaknesses in Credit Unions so that potential financial failures can be predicted. DEA with a VRS frontier and input orientation is utilised to create various production models that are compared with each other, and with current models used by DICO. In total, fifteen models are constructed and compared with DICO's current z-score model. A simple equity/asset ratio is shown to provide as good a prediction of failure as any of the other models, and is not improved upon the z-score model. The best DEA model provides results comparable to the equity/asset ratio when the new slack adjusted efficiency score is used to measure efficiency, particularly for larger asset sizes. For each Credit Union, comparison is made with a peer group of efficient entities that the inefficient institution's management can emulate, in order to improve their performance.
Visual perception and visual motor skills at four years of age of neurologically normal, extremely low birth weight children with neonatal periventricular brain injury

The study examines the effects of periventricular brain insult on a group of extremely low birthweight (ELBW) infants at four years corrected age on measures of visual perception, memory, motor planning and visual spatial manipulation. The performance of 60 ELBW children, divided into three groups with varying degrees of periventricular brain insult, is compared to a group of 22 ELBW children without brain insult. The groups are comparable in terms of gestational age, birthweight, days ventilated, bronchopulmonary dysplagia, and size for gestational age. Visual motor integration was unimpaired in all children assessed regardless of brain insult status. Increasing frequency of deficits in the interpretation of visual spatial information and motor planning are associated with periventricular damage. This reaches statistical significance when the most severely affected children with periventricular leukomalacia or periventricular echoes are compared to the no insult preterm group. There is also a trend for difficulties on tasks involving visual perceptual information and memory to be associated with increasing severity of brain insult but, the differences are not statistically significant.
Investigating the truth effect in young and elderly consumers, the role of recognition and source memory

Repetition of advertising claims increases belief in those claims, this phenomenon, called the 'truth effect', is mediated by consumers' memory for the claims. Since memory is not a unitary phenomenon, memory for the item (i.e. the advertising claim) and memory for the source of the item (i.e. where the claim was encountered) may have a differential impact on the truth effect. This may be of particular importance as older adults often show memory deficits compared to younger adults, and may even be particularly poor in remembering source information. Fortunately, it is possible to minimize these memory deficits through cognitive support. Therefore, the questions addressed in this dissertation are: Do declines in memory make the elderly more vulnerable to the truth effect? Are there conditions under which age-related differences in the truth effect can be abolished? Experiment 1 assessed the level of memory impairment in the elderly as compared to the young, and its influence on the truth effect. The elderly were mom susceptible to the truth effect and this effect was mediated via their higher false-alarm rates and poorer source memory. Experiment 2 demonstrated that if one used imagery instructions at encoding, a form of cognitive support that ameliorates elderly item memory and source memory deficits, then the truth effect differences between the young and the elderly disappear. Taken together, these experiments showed that the elderly are more susceptible to truth effect due to poorer memory, and if their memory is enhanced using cognitive support, their susceptibilty to the truth effect can be overcome. Experiment 3 was designed to investigate the impact of source credibility on the truth rating of an item. While earlier research had suggested that source credibility influences truth ratings, it was not clear when the credible source exerts its influence--is it when one is exposed to an advertising claim (at encoding), or, when it is subsequently remembered (at retrieval), or, at both times? Experiment 3 showed that while the credibility of source at encoding as well as the source remembered at retrieval influenced truth ratings of a claim, the source at retrieval influenced truth ratings the most.
Teaching teachers to teach reading, a self-study

This interpretive inquiry is an ongoing self-study about my learning to teach a preservice reading-education course. The aim of the inquiry is to understand the experience of learning to teach from the perspective of a beginning professor. The participants were myself and my students over the course of five years. The data include: my reflective journal as a beginning professor documenting a growing awareness of the context of teaching preservice reading-teachers; and the preservice students' journals and tape-recorded interviews documenting their experiences in learning to teach reading during the course, during the practicum following the course, and during their first year of teaching. Analysis of the data draws heavily on Russell's ("Returning to the physics classroom," 1995) conception of competing authorities and is discussed in the context of: (1) an examination of three early formative experiences in my learning to teach; (2) three letters addressed to my students concerning learning to teach reading and the problems posed by the practicum and the current state of reading instruction, and the substantive changes I have made in the teaching of this course. The study concludes with a discussion of projects that I have initiated to help my students develop a thorough understanding of teaching reading and a discussion of the tensions and dilemmas related to these projects.
Elafin inhibition of fibronectin synthesis and inflammatory cell proliferation, and reduction of post-cardiac transplant coronary arteriopathy and myocardial necrosis, in vitro and in vivo mechanisms

Post-cardiac transplant coronary arteriopathy, a major complication of long-term heart allograft survival has profound implications on the morbidity and mortality of cardiac transplant recipients. We assessed the functional impact of elastolytic activity on the development of coronary artery (CA) neointimal formation following cardiac transplantation and investigated the pathophysiological relationship between interleukin (IL)-1ß-induced CA smooth muscle cell (SMC) fibronectin (FN) synthesis and elevated levels of donor coronary artery serine elastolytic activity. The impact of elastolytic activity on post-cardiac transplant CA neointimal formation was assessed by intravenous administration of the specific human elastolytic inhibitor elafin in a rabbit heterotopic cardiac transplantation model. In this model, elafin inhibition of elastolytic activity was associated with both a marked reduction in the number and severity of allograft CA intimal lesions. Elastolytic inhibition also resulted in reduced vascular FN expression and inflammatory and SMC proliferation. These findings were associated with a marked reduction in myocardial necrosis, myocardial elastolytic activity, and inflammatory cell proliferation, never observed in our previous studies of allograft arteriopathy. Experiments using elafin and the non-selective serine proteinase inhibitor (PI) alpha1-PI (Ã1-PI), identified that elastolytic activity specifically modulated IL-1ß-induced porcine CA SMC FN synthesis, as these agents had no effect on other IL-1ß functions. Northern analyses provided evidence that elastase inhibitors reduced FN by a post-transcriptional mechanism. Elastase inhibitors also reduced IL-1ß-induced SMC elastase activity and increase in elastin derived peptides (EDP). This feature was inhibited completely by Ã1-PI, and modestly by elafin. The inhibitory effect of elafin was bypassed by human leukocyte elastase-generated porcine aortic EDP. These peptides synergized with IL-1ß in its FN-stimulatory effect further implicating these compounds in IL-1ß mediated FN synthesis. However, addition of these EDP could not overcome the inhibitory effect of Ã1-PI, implying an additional requirement for non-elastase serine proteinase activity. Our observations suggest that increased elastolytic activity induces FN production in allograft CA neointimal formation, contributes to myocardial necrosis, and modulates matrix proteins and growth factors involved in inflammatory and SMC proliferation. Endogenous EDP and non-elastase serine proteinases are required for IL-1ß-induction of SMC FN synthesis.