In an era of extreme competition and pursuit of economic success, the competition between corporations has extended to the integration of supply chain management in search of economic leverage over their competitors. Today, outsourcing is deemed as an integral part of supply chain management and increasing number of companies use outsourcing as vital elements in their business strategies. Companies having an established and cooperative supply chain will enhance their competitive strength. As a manufacturing company, outsourcing is closely tied with production management and treated as an extension of one's own manufacturing capacity. However, manufacturing companies are faced with unique outsourcing problems; such as manufacturing delays impacting and requiring rearrangement of one's own master production plan as well as resulting bottle necks caused by parts shortages and idle capacity while waiting for parts. This thesis focuses upon methods that can be taken both in-house and at the outside production provider to reduce the bottlenecks and avoid idle equipment capacity to assure the specification compliant parts are available in the right quantity at the right time to ensure the product throughput necessary to promote the company¡¦s competitive strength. This thesis incorporates the Thinking Process of Theory of Constrains in developing the proposed solutions to eliminate the undesirable effects and core conflicts associated with Outsourcing Subcontract Management at Aero Engine Factory of the Aerospace Industrial Development Corporation. The proposed Real Time Platform of Collaboration Manufacturing System principally includes the use of; Material Pre-release Notices, Daily Work Orders & Sequence Monitoring, Supplier Non-compliance Reports, E-technical Data & Drawings, E-receiving & Inspection, Supplier Performance Evaluations with TDD concept, Tooling & Fixture Borrowing, and Training & Certification. The proposed method has proven effective in reducing outsourcing cycle time by 32.71% and has improved the on time delivery rate from 84.32% to 93.81% and the date of late delivery from 1.24 to 0.22 in average from the study period between January 2009 through November 2009 according to data collected by Aero Engine Factory Outsourcing Team.

This work presents an alternative method for 3D bipedal gait design using independent controllers for the plane of motion frontal and sagittal. The use of virtual constraints to design a stable gait for the frontal system is fully developed and studied in this work and the resulting gait simulated. The results, although not definitive, are promising. / Esta tese apresenta um método alternativo de síntese de marcha bípede 3D usando controladores independentes projetados para os planos de movimento frontal e sagital. O uso de restrições virtuais no projeto de uma marcha estável para o plano frontal é completamente desenvolvido e estudado neste trabalho. A marcha resultante é simulada e os resultados, apesar de ainda não definitivos, são promissores.

Orientador: Ana Maria Pellegrini / Banca: Cynthia Yukiko Hiraga / Banca: José Angelo Barela / Resumo: A coordenação intermembros é exigida em inúmeras atividades motoras. Nestas atividades, os indivíduos precisam coordenar muitos componentes do corpo, mantendo relações entre eles e destes com o ambiente. Em um sistema dinâmico complexo, as relações entre as partes do sistema limitam ou influenciam o comportamento de outras partes, levando à emergência de padrões de coordenação. Crianças com Transtorno do Desenvolvimento da Coordenação (TDC) têm sido caracterizadas por apresentarem dificuldade em coordenar ritmicamente as partes do corpo em padrões específicos de coordenação intermembros. O presente estudo investigou a emergência e a estabilidade de padrões motores de crianças com TDC em uma tarefa rítmica de coordenação intermembros, analisando suas capacidades de sincronizar os deslocamentos dos membros superiores e inferiores em diferentes superfícies de apoio. Doze crianças com Desenvolvimento Típico (DT) e 12 crianças com TDC realizaram a tarefa de saltar e bater palma, durante 15 segundos, em duas superfícies: rígida (chão) e elástica (mini-trampolim). Foi solicitado à criança saltar e bater palma em quatro condições de coordenação: (i) de livre escolha do participante - Livre; (ii) batendo palma toda vez que os pés tocavam a superfície de apoio - Palma em Baixo; (iii) batendo palma toda vez que o corpo alcançava a máxima altura do salto - Palma em Cima; e (iv) batendo palma toda vez que os pés tocavam a superfície de apoio e toda vez que o corpo alcançava a máxima altura do salto - Duas Palmas. Quando a tarefa foi executada na condição Livre, os resultados mostraram que o padrão emergente das crianças com TDC foi diferente e mais variável na superfície mini-trampolim comparado com o das crianças com DT e com o delas mesmas na superfície chão. Além disso, na condição Palma em Baixo e Palma em Cima, as crianças... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Interlimb coordination is required in many motor activities. To perform these activities, people have to coordinate all body segments at the same time, keeping a relationship between segments and with the environment. In a complex dynamic system, the relationships between its parts limit or influence the behavior of other parts, so coordination patterns emerge. Children with Developmental Coordination Disorder (DCD) have been characterized by showing difficulty in rhythmically coordinate body segments, in specific interlimb coordination patterns. The purpose of this study was to investigate the emergency and stability of coordination patterns in children with DCD when they perform a rhythmic interlimb coordination task, analyzing their abilities to synchronize the movements of upper and lower limbs in two different surfaces. Twelve children with Typical Development (TD) and 12 children with DCD performed a jumping and clapping task during 15 seconds in two surfaces: rigid (on the floor) and elastic (on the mini-tramp). Children were required to clap while jumping (i) in their chosen pattern - Free; (ii) when the feet touched on the surface - Clapping-surface; (iii) when the body reached the maximum jumping height - Clapping-jumping; and (iv) when the feet touched the surface and when the body reached the maximum jumping height - Clapping-both. For the Free condition, the results showed that the DCD children emergent pattern was different and more variable on the mini-tramp than on the floor as compared with TD children coordination pattern. Furthermore, children with DCD were more variable in Clapping-surface and Clapping-jumping conditions compared with TD children. Clapping-jumping condition, characterized by relative phase of 180°, was more difficult for both DCD and TD children to perform than Clapping-surface condition, characterized by relative phase... (Complete abstract click electronic access below) / Mestre

Depuis l'invention du transistor dans les années 50, les performances des composants microélectroniques n'ont cessé de progresser, en passant notamment par l'augmentation de leur densité. Malheureusement, la miniaturisation des composants augmente les coûts de fabrication de façon prohibitive. Une solution, permettant d'accroître la densification et les fonctionnalités tout en limitant les coûts, passe par l'empilement des composants microélectroniques. Leurs connexions électriques s'effectuent alors à l'aide d'interconnexions verticales soudées au moyen d'un joint de brasure. Afin d'empêcher leurs ruptures lors des dilatations thermiques, les interconnexions sont protégées au moyen d'un polymère underfill. L'objectif de cette thèse est d'évaluer la faisabilité et la pertinence d'une nouvelle solution de remplissage par polymère, appelée wafer-level underfill (WLUF). L'écoulement de l'underfill durant l'étape d'assemblage des composants est modélisé afin de prédire les paramètres de scellement idéaux, permettant la formation des interconnexions électriques. Puis, l'intégration de nouveaux underfills, possédant des propriétés thermomécaniques différentes, pouvant affecter l'intégrité et le fonctionnement du dispositif, l'étude de la fiabilité du procédé WLUF et, par conséquent, l'évaluation de sa possibilité d'industrialisation est effectuée. / Since the invention of the transistor in the Fifties, performances of microelectronics components did not cease progressing thanks to their density increase. Unfortunately, miniaturization of components increases manufacturing costs in a prohibitory way. A solution, allowing densification and functionalization increase without costs rise, is microelectronics components stack. Their electrical connections are carried out using vertical interconnections welded by means of solder joints. In order to prevent their ruptures during thermal dilatations, interconnections are protected thanks to polymer underfill. The objective of this thesis is to evaluate the feasibility and the relevance of a new solution of polymer filling, called wafer-level underfill (WLUF). Flow of underfill during components assembly step is modeled in order to predict ideal bonding parameters, allowing electrical interconnections formation. Then, integration of new underfills, having different thermomechanical properties, being able to affect device integrity and functioning, the study of WLUF process reliability and, consequently, the evaluation of its industrialization possibility is carried out.

Made available in DSpace on 2014-06-11T19:22:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-17Bitstream added on 2014-06-13T19:08:25Z : No. of bitstreams: 1 ferracioli_mc_me_rcla.pdf: 395950 bytes, checksum: 238b3a5cfad916ec4fe2d5b841ccbae2 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A coordenação intermembros é exigida em inúmeras atividades motoras. Nestas atividades, os indivíduos precisam coordenar muitos componentes do corpo, mantendo relações entre eles e destes com o ambiente. Em um sistema dinâmico complexo, as relações entre as partes do sistema limitam ou influenciam o comportamento de outras partes, levando à emergência de padrões de coordenação. Crianças com Transtorno do Desenvolvimento da Coordenação (TDC) têm sido caracterizadas por apresentarem dificuldade em coordenar ritmicamente as partes do corpo em padrões específicos de coordenação intermembros. O presente estudo investigou a emergência e a estabilidade de padrões motores de crianças com TDC em uma tarefa rítmica de coordenação intermembros, analisando suas capacidades de sincronizar os deslocamentos dos membros superiores e inferiores em diferentes superfícies de apoio. Doze crianças com Desenvolvimento Típico (DT) e 12 crianças com TDC realizaram a tarefa de saltar e bater palma, durante 15 segundos, em duas superfícies: rígida (chão) e elástica (mini-trampolim). Foi solicitado à criança saltar e bater palma em quatro condições de coordenação: (i) de livre escolha do participante – Livre; (ii) batendo palma toda vez que os pés tocavam a superfície de apoio – Palma em Baixo; (iii) batendo palma toda vez que o corpo alcançava a máxima altura do salto – Palma em Cima; e (iv) batendo palma toda vez que os pés tocavam a superfície de apoio e toda vez que o corpo alcançava a máxima altura do salto – Duas Palmas. Quando a tarefa foi executada na condição Livre, os resultados mostraram que o padrão emergente das crianças com TDC foi diferente e mais variável na superfície mini-trampolim comparado com o das crianças com DT e com o delas mesmas na superfície chão. Além disso, na condição Palma em Baixo e Palma em Cima, as crianças... / Interlimb coordination is required in many motor activities. To perform these activities, people have to coordinate all body segments at the same time, keeping a relationship between segments and with the environment. In a complex dynamic system, the relationships between its parts limit or influence the behavior of other parts, so coordination patterns emerge. Children with Developmental Coordination Disorder (DCD) have been characterized by showing difficulty in rhythmically coordinate body segments, in specific interlimb coordination patterns. The purpose of this study was to investigate the emergency and stability of coordination patterns in children with DCD when they perform a rhythmic interlimb coordination task, analyzing their abilities to synchronize the movements of upper and lower limbs in two different surfaces. Twelve children with Typical Development (TD) and 12 children with DCD performed a jumping and clapping task during 15 seconds in two surfaces: rigid (on the floor) and elastic (on the mini-tramp). Children were required to clap while jumping (i) in their chosen pattern - Free; (ii) when the feet touched on the surface - Clapping-surface; (iii) when the body reached the maximum jumping height - Clapping-jumping; and (iv) when the feet touched the surface and when the body reached the maximum jumping height - Clapping-both. For the Free condition, the results showed that the DCD children emergent pattern was different and more variable on the mini-tramp than on the floor as compared with TD children coordination pattern. Furthermore, children with DCD were more variable in Clapping-surface and Clapping-jumping conditions compared with TD children. Clapping-jumping condition, characterized by relative phase of 180°, was more difficult for both DCD and TD children to perform than Clapping-surface condition, characterized by relative phase... (Complete abstract click electronic access below)

This master’s thesis analyses problems which are related to planning of orders in form of projects in custom manufacturing in a particular company. The basic for this work is the evaluation of analysis of actual planning of orders situation. On the basis of this analysis is proposed further recommendation for optimalization of project planning in custom Manufacturing whose creating was the main content this master’s thesis.

Dans cette thèse, on étudie des problèmes de propagation du chaos et de limite de champ moyen pour des modèles relatant le comportement collectif d'individus ou de particules. Particulièrement, on se place dans des cas où l'interaction entre ces individus/particules est discontinue. Le premier travail établit la propagation du chaos pour l'équation de Vlasov-Poisson-Fokker-Planck 1d. Plus précisément, on montre que la distribution des particules évoluant sur la droite des réels interagissant via la fonction signe, converge vers la solution de l'équation de VPFP 1d, en probabilité par des techniques de type grandes déviations, et en espérance par des techniques de loi des grands nombre. Dans le second travail, on étudie une variante du modèle de Cucker-Smale, où le noyau de communication est l'indicatrice d'un cône dont l'orientation dépend de la vitesse de l'individu. Une estimation de stabilité fort-faible en distance de M.K.W. est obtenue, qui implique la limite de champ moyen. Le troisième travail a consisté à introduire de la diffusion en vitesse dans le modèle précédemment cité. Cependant, il faut ajouter une diffusion tronquée afin de préserver un système dans lequel les vitesses restent uniformément bornées. Finalement, on étudie une variante de l'équation d'agrégation où l'interaction entre individus est donnée par un cône dont l'orientation dépend de la position de l'individu. Dans ce cas on peut seulement donner une estimation de stabilité fort-faible en distance $W_\infty$, et le modèle doit être posé dans un domaine borné dans le cas avec diffusion. / In this thesis, we study some propagation of chaos and mean field limit problems arising in modelisation of collective behavior of individuals or particles. Particularly, we set ourselves in the case where the interaction between the individuals/particles is discontinuous. The first work establihes the propagation of chaos for the 1d Vlasov-Poisson-Fokker-Planck equation. More precisely, we show that the distribution of particles evolving on the real line and interacting through the sign function converges to the solution of the 1d VPFP equation, in probability by large deviations-like techniques, and in expectation by law of large numbers-like techniques. In the second work, we study a variant of the Cucker-Smale, where the communication weight is the indicatrix function of a cone which orientation depends on the velocity of the individual. Some weak-strong stability estimate in M.K.W. distance is obtained for the limit equation, which implies the mean field limit. The third work consists in adding some diffusion in velocity to the model previously quoted. However one must add some truncated diffusion in order to preserve a system in which velocities remain unifomrly bounded. Finally we study a variant of the aggregation equation where the interaction between individuals is also given by a cone which orientation depends on the position of the individual. In this case we are only able to provide some weak-strong stability estimate in $W_\infty$ distance, and the problem must be set in a bounded domain for the case with diffusion.

The main aim of this thesis is identification of a new type of time-space constrain related to everyday life of young women aged 18 to 26 years. Semi-structured interviews and mental maps were recorded in the city parts Praha 15 and Petrovice with the aim to identify the perceptual barrier, whose temporal definition applies in particular to the evening hours and drkness. Space exposure of this barrier is registered through using the routine paths especially in avoiding certain places in night time. Dangerous places of this area were discussed too. Identified barrier women overcome by using special strategies - movement, mind and security, which works together in certain situations. Perception of sense of danger is factor, which influences quality of life, thereby should be a wide interest in this issue.

The present thesis deals with the study of vision techniques for the detection of human pose based on the analysis of a single image, as well as the tracking of these poses along a sequence of images. It is proposed to model the human pose by four kinematic chains that model the four articulated extremities. These kinematic chains and head remain attached to the body. The four kinematic chains are composed by three keypoints. Therefore, the model initially has a total of $14$ parts. In this thesis it is proposed to modify the technique called Deformable Parts Model (DPM), adding the depth channel. Initially, the DPM model was defined over three RGB channel images. While in this thesis it is proposed to work on images of four RGBD channels, so the proposed extension is called 4D-DPM. The experiments performed with 4D-DPM demonstrate an improvement in the accuracy of pose detection with respect to the initial DPM model, at the cost of increasing its computational cost when treating an additional channel. On the other hand, it is defined to reduce the previous computational cost by simplifying the model that defines the human pose. The idea is to reduce the number of variables to be detected with the 4D-DPM model, so that the suppressed variables can be calculated from the detected variables using inverse kinematics models based on dual quaternions. In addition, it is proposed to use a particle filter models to continue improving the accuracy of detection of human poses along a sequence of images. Considering the problem of detection and monitoring of human body pose along a video sequence, this thesis proposes the use of the following method. 1. Camara calibration. RGBD image processing. Subtraction of the image background with the MSER method. 2. 4D-DPM: method used to detect the keypoints (variables of the pose model) within an image. 3. Particle filters: this type of filter is designed to track the keypoints over time and correct the data obtained by the sensor. 4. Inverse kinematic modeling: the control of kinematic chains is performed with the help of dual cuaternions in order to obtain the complete pose model of the human body. The overall contribution of this thesis is the proposal of the previous method that, combining the previous methods, is able to improve the accuracy in the detection and the follow up of the human body pose in a video sequence, also reducing its computational cost . This is possible due to the combination of the 4D-DPM method with the use of inverse kinematics techniques. The original DPM method should detect $14$ point of interest on an RGB image to estimate the human pose. However, the proposed method, where a point of interest for each limb is removed, must detect $10$ point of interest on an RGBD image. Subsequently, the eliminated $4$ point of interest are calculated by using inverse kinematics methods from the calculated $10$ point of interest. To solve the problem of inverse kinematics a dual quaternions methods is proposed for each of the $4$ kinematic chains that model the extremities of the skeleton of the human body. The particle filter is applied over the time sequence of the 10 points of interest of the posture model detected through the 4D-DPM method. To design these particle filters it is proposed to add the following restrictions to weight the particles generated: 1. Restrictions on joint limits. 2. Softness restrictions. 3. Collision detection. 4. Projection of poly-spheres / La presente tesis trata sobre el estudio de técnicas de visión para la detección de la postura del esqueleto del cuerpo humano basada en el análisis de una sola imagen, además del seguimiento de estas posturas a lo largo de una secuencia de imágenes. Se propone modelar la postura del esqueleto cuerpo humano mediante cuatro cadenas cinemáticas que modelan las cuatro extremidades articuladas. Estas cadenas cinemáticas y la cabeza permanecen unidas al cuerpo. Las cuatro cadenas cinemáticas se componen de tres puntos de interés. Por lo tanto, el modelo inicialmente dispone de un total de 14 puntos de interés. En esta tesis se propone modificar la técnica denominada Deformable Parts Model (DPM), añadiendo el canal de profundidad denominado ``Depth''. Inicialmente el modelo DPM se definió sobre imágenes de tres canales RGB. Mientras que en esta tesis se propone trabajar sobre imágenes de cuatro canales RGBD, por ello a la ampliación propuesta se le denomina 4D-DPM. Por otra parte, se propone reducir el coste computacional anterior simplificando el modelo que define la postura del cuerpo humano. La idea es reducir el número de variables a detectar con el modelo 4D-DPM, de tal manera que las variables suprimidas se puedan calcular a partir de las variables detectadas, utilizando modelos de cinemática inversa basados en cuaterniones duales. Los experimentos realizados demuestran que la combinación de estas dos técnicas permite, reduciendo el coste computacional del método original DPM, mejorar la precisión de la detección de postura debido a la información extra del canal de profundidad. Adicionalmente, se propone utilizar modelos de filtros de partículas para continuar mejorando la precisión de la detección de las posturas humanas a lo largo de una secuencia de imágenes. Atendiendo al problema de detección y seguimiento de las postura del esqueleto del cuerpo humano a lo largo de una secuencia de vídeo, esta tesis propone el uso del siguiente método. 1. Calibración de cámaras. Procesamiento de imágenes RGBD. Sustracción del fondo de la imagen con el método MSER. 2. 4D-DPM: método utilizado para detectar los puntos de interés (variables del modelo de postura) dentro de una imagen. 3. Filtros de partículas: se diseña este tipo de filtros para realizar el seguimiento de los puntos de interés a lo largo del tiempo y corregir los datos obtenidos por el sensor. 4. Modelado cinemático inverso: se realiza el control de cadenas cinemáticas con la ayuda de cuaterniones duales con el fin de obtener el modelo completo de la postura del esqueleto del cuerpo humano. La contribución global de esta tesis es la propuesta del método anterior que, combinando los métodos anteriores, es capaz de mejorar la precisión en la detección y el seguimiento de la postura del esqueleto del cuerpo humano en una secuencia de vídeo, reduciendo además su coste computacional. El método original DPM debe detectar 14 puntos de interés sobre una imagen RGB para estimar la postura de un cuerpo humano. Sin embargo, el método propuesto debe detectar 10 puntos de interés sobre una imagen RGBD. Posteriormente, los 4 puntos de interés eliminados se calculan mediante la utilización de métodos de cinemática inversa a partir de los 10 puntos de interés calculados. Para resolver el problema de la cinemática inversa se propone utilizar cuaterniones duales para cada una de las 4 cadenas cinemáticas que modelan las extremidades del esqueleto del cuerpo humano. El filtro de partículas se aplica sobre la secuencia temporal de los 10 puntos de interés del modelo de postura detectados a través del método 4D-DPM. Para diseñar estos filtros de partículas se propone añadir las siguientes restricciones, explicadas en la memoria, para ponderar las partículas generadas: 1. Restricciones en los límites de articulaciones. 2. Restricciones de suavidad. 3. Detección de colisiones. 4. Proyección de las poli-esferas. / La present tesi tracta sobre l'estudi de tècniques de visió per a la detecció de la postura de l'esquelet del cos humà basada en l'anàlisi d'una sola imatge, a més del seguiment d'estes postures al llarg d'una seqüència d'imatges. Es proposa modelar la postura de l'esquelet del cos humà per mitjà de quatre cadenes cinemàtiques que modelen les quatre extremitats articulades. Estes cadenes cinemàtiques i el cap romanen unides al cos. Les quatre cadenes cinemàtiques es componen de tres punts d'interés. Per tant, el model inicialment disposa d'un total de $14$ punts d'interés. En esta tesi es proposa modificar la tècnica denominada Deformable Parts Model (DPM) , afegint el canal de profunditat denominat ``Depth''. Inicialment el model DPM es va definir sobre imatges de tres canals RGB. Mentres que en esta tesi es proposa treballar sobre imatges de quatre canals RGBD, per això a l'ampliació proposada se la denomina 4D-DPM. D'altra banda, es proposa reduir el cost computacional anterior simplificant el model que definix la postura del cos humà. La idea és reduir el nombre de variables a detectar amb el model 4D-DPM, de tal manera que les variables suprimides es puguen calcular a partir de les variables detectades, utilitzant models de cinemàtica inversa basats en quaternions duals. Els experiments realitzats demostren que la combinació d'estes dos tècniques permet, reduint el cost computacional del mètode original DPM, millorar la precisió de la detecció de la postura degut a la informació extra del canal de profunditat. Addicionalment, es proposa utilitzar models de filtres de partícules per a continuar millorant la precisió de la detecció de les postures humanes al llarg d'una seqüència d'imatges. Atenent al problema de detecció i seguiment de les postura de l'esquelet del cos humà al llarg d'una seqüència de vídeo, esta tesi proposa l'ús del següent mètode. 1. Calibratge de càmeres. Processament d'imatges RGBD. Sostracció del fons de la imatge amb el mètode MSER. 2. 4D-DPM: mètode utilitzat per a detectar els punts d'interés (variables del model de postura) dins d'una imatge. 3. Filtres de partícules: es dissenya este tipus de filtres per a realitzar el seguiment dels punts d'interés al llarg del temps i corregir les dades obtingudes pel sensor. 4. Modelatge cinemàtic invers: es realitza el control de cadenes cinemàtiques amb l'ajuda de quaternions duals a fi d'obtindre el model complet de l'esquelet del cos humà. La contribució global d'esta tesi és la proposta del mètode anterior que, combinant els mètodes anteriors, és capaç de millorar la precisió en la detecció i el seguiment de la postura de l'esquelet del cos humà en una seqüència de vídeo, reduint a més el seu cost computacional. Açò és possible a causa de la combinació del mètode 4D-DPM amb la utilització de tècniques de cinemàtica inversa. El mètode original DPM ha de detectar 14 punts d'interés sobre una imatge RGB per a estimar la postura d'un cos humà. No obstant això, el mètode proposat ha de detectar 10 punts d'interés sobre una imatge RGBD. Posteriorment, els 4 punts d'interés eliminats es calculen per mitjà de la utilització de mètodes de cinemàtica inversa a partir dels 10 punts d'interés calculats. Per a resoldre el problema de la cinemàtica inversa es proposa utilitzar quaternions duals per a cada una de les 4 cadenes cinemàtiques que modelen les extremitats de l'esquelet del cos humà. El filtre de partícules s'aplica sobre la seqüència temporal dels 10 punts d'interés del model de postura detectats a través del mètode 4D-DPM. Per a dissenyar estos filtres de partícules es proposa afegir les següents restriccions per a ponderar les partícules generades: 1. Restriccions en els límits d'articulacions. 2. Restriccions de suavitat. 3. Detecció de col·lisions. 4. Projecció de les poli-esferes. / Martínez Bertí, E. (2017). SEGUIMIENTO DE PERSONAS APLICANDO RESTRICCIONES CINEMÁTICAS BASADAS EN MODELOS DE CUERPOS RÍGIDOS ARTICULADOS [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86159

Many analysts believe that problems in the U.S. housing market initiated the 2008–2010 global financial crisis. In this regard, the subprime mortgage crisis (SMC) shook the foundations of the financial industry by causing the failure of many iconic Wall Street investment banks and prominent depository institutions. This crisis stymied credit extension to households and businesses thus creating credit crunches and, ultimately, a global recession. This thesis specifically discusses the SMC and its components, causes, consequences and cures in relation to subprime mortgages, securitization, as well as data. In particular, the SMC has highlighted the fact that risk, credit ratings, profit and valuation as well as capital regulation are important banking considerations. With regard to risk, the thesis discusses credit (including counterparty), market (including interest rate, basis, prepayment, liquidity and price), tranching (including maturity mismatch and synthetic), operational (including house appraisal, valuation and compensation) and systemic (including maturity transformation) risks. The thesis introduces the IDIOM hypothesis that postulates that the SMC was largely caused by the intricacy and design of subprime agents, mortgage origination and securitization that led to information problems (loss, asymmetry and contagion), valuation opaqueness and ineffective risk mitigation. It also contains appropriate examples, discussions, timelines as well as appendices about the main results on the aforementioned topics. Numerous references point to the material not covered in the thesis, and indicate some avenues for further research. In the thesis, the primary subprime agents that we consider are house appraisers (HAs), mortgage brokers (MBs), mortgagors (MRs), servicers (SRs), SOR mortgage insurers (SOMIs), trustees, underwriters, credit rating agencies (CRAs), credit enhancement providers (CEPs) and monoline insurers (MLIs). Furthermore, the banks that we study are subprime interbank lenders (SILs), subprime originators (SORs), subprime dealer banks (SDBs) and their special purpose vehicles (SPVs) such as Wall Street investment banks and their special structures as well as subprime investing banks (SIBs). The main components of the SMC are MRs, the housing market, SDBs/hedge funds/money market funds/SIBs, the economy as well as the government (G) and central banks. Here, G either plays a regulatory or policymaking role. Most of the aforementioned agents and banks are assumed to be risk neutral with SOR being the exception since it can be risk (and regret) averse on occasion. The main aspects of the SMC - subprime mortgages, securitization, as well as data - that we cover in this thesis and the chapters in which they are found are outlined below. In Chapter 2, we discuss the dynamics of subprime SORs' risk and profit as well as their valuation under mortgage origination. In particular, we model subprime mortgages that are able to fully amortize, voluntarily prepay or default and construct a discrete–time model for SOR risk and profit incorporating costs of funds and mortgage insurance as well as mortgage losses. In addition, we show how high loan–to–value ratios due to declining housing prices curtailed the refinancing of subprime mortgages, while low ratios imply favorable house equity for subprime MRs. Chapter 3 investigates the securitization of subprime mortgages into structured mortgage products such as subprime residential mortgage–backed securities (RMBSs) and collateralized debt obligations (CDOs). In this regard, our discussions focus on information, risk and valuation as well as the role of capital under RMBSs and RMBS CDOs. Our research supports the view that incentives to monitor mortgages has been all but removed when changing from a traditional mortgage model to a subprime mortgage model. In the latter context, we provide formulas for IB's profit and valuation under RMBSs and RMBS CDOs. This is illustrated via several examples. Chapter 3 also explores the relationship between mortgage securitization and capital under Basel regulation and the SMC. This involves studying bank credit and capital under the Basel II paradigm where risk–weights vary. Further issues dealt with are the quantity and pricing of RMBSs, RMBS CDOs as well as capital under Basel regulation. Furthermore, we investigate subprime RMBSs and their rates with slack and holding constraints. Also, we examine the effect of SMC–induced credit rating shocks in future periods on subprime RMBSs and RMBS payout rates. A key problem is whether Basel capital regulation exacerbated the SMC. Very importantly, the thesis answers this question in the affirmative. Chapter 4 explores issues related to subprime data. In particular, we present mortgage and securitization level data and forge connections with the results presented in Chapters 2 and 3. The work presented in this thesis is based on 2 peer–reviewed chapters in books (see [99] and [104]), 2 peer–reviewed international journal articles (see [48] and [101]), and 2 peer–reviewed conference proceeding papers (see [102] and [103]). / Thesis (Ph.D. (Applied Mathematics))--North-West University, Potchefstroom Campus, 2011.