A nonlinear programming technique is applied to the optimization of the thrust and lift control histories for missiles. The first problem considered is that of determining the thrust history which maximizes the range of a continuously-variable (non-pulsed) thrust rocket in horizontal lifting flight. The optimal control solution for this problem is developed. The problem is then approximated by a parameter optimization problem which is solved using a second-order, quasi-Newton method with constraint projection. The two solutions are found to compare well. This result allows confidence in the use of the nonlinear-programming technique to solve optimization problems in flight mechanics for which no analytical optimal-control solutions exist. Such a problem is to determine the thrust and lift histories which maximize the final velocity of a multiple-pulse missile. This problem is solved for both horizontal- and elevation-plane trajectories with and without final time constraints. The method is found to perform well in the solution of these optimization problems and to yield substantial improvements in performance over the nominal trajectories. / M.S.

While machine learning (ML) methods have achieved considerable success on several mainstream problems in vision and language modeling, they are still challenged by their lack of interpretable decision-making that is consistent with scientific knowledge, limiting their applicability for scientific discovery applications. Recently, a new field of machine learning that infuses domain knowledge into data-driven ML approaches, termed Knowledge-Guided Machine Learning (KGML), has gained traction to address the challenges of traditional ML. Nonetheless, the inner workings of KGML models and algorithms are still not fully understood, and a better comprehension of its advantages and pitfalls over a suite of scientific applications is yet to be realized. In this thesis, I first tackle the task of understanding the role KGML plays at shaping the outputs of a neural network, including its latent space, and how such influence could be harnessed to achieve desirable properties, including robustness, generalizability beyond training data, and capturing knowledge priors that are of importance to experts. Second, I use and further develop loss landscape visualization tools to better understand ML model optimization at the network parameter level. Such an understanding has proven to be effective at evaluating and diagnosing different model architectures and loss functions in the field of KGML, with potential applications to a broad class of ML problems. / Doctor of Philosophy / My research aims to address some of the major shortcomings of machine learning, namely its opaque decision-making process and the inadequate understanding of its inner workings when applied in scientific problems. In this thesis, I address some of these shortcomings by investigating the effect of supplementing the traditionally data-centric method with human knowledge. This includes developing visualization tools that make understanding such practice and further advancing it easier. Conducting this research is critical to achieving wider adoption of machine learning in scientific fields as it builds up the community's confidence not only in the accuracy of the framework's results, but also in its ability to provide satisfactory rationale.

Computed tomographic colonography(CTC), also called virtual colonoscopy, uses CT scanning and computer post-processing to create two dimensional images and three dimensional virtual views inside of the colon. Computer-aided polyp detection(CAPD) automatically detects colonic polyps and presents them to the user in either a first or second reader paradigm, with a goal reducing examination time while increasing the detection sensitivity. During colonoscopy, the endoscopists use the colonoscope inside of a patient's colon to target potential polyps and validate CAPD found ones. However, there is no direct information linking between CT images and the real-time optical colonoscopy(OC) video provided during the operation, thus endoscopists need to rely largely on their past experience to locate and remove polyps. The goal of this research project is to study the feasibility of developing an image guided colonoscopy(IGC) system that combines CTC images, real-time colonoscope position measurements, and video stream to validate and guide the removal of polyps found in CAPD. System would ease polyp level validation of CTC and improve the accuracy and efficiency of guiding the endoscopist to the target polyps. In this research project, a centerline based matching algorithm has been designed to estimate, in real time, the relative location of the colonoscope in the virtual colonoscopy environment. Furthermore, the feasibility of applying online simultaneous localization and mapping(SLAM) into CT image guided colonoscopy has been evaluated to further improve the performance of localizing and removing the pre-defined target polyps. A colon phantom is used to provide a testing setup to assess the performance of the proposed algorithms. / Master of Science

Ålö AB is a world-leading company in agricultural equipment. They sell and manufacture front loaders and implement solutions for tractors. The transport solution currently used in assembly is outdated and must be replaced in the near future. The purpose of the project was to carry out a preliminary investigation to provide increased knowledge for future decisions regarding the implementation of a new transport system. The investigation was conducted through a literature review and observation of the existing transport system. Additionally, a market survey of the transport systems has also been performed. The study is based on theories such as 5s and the Toyota Production system (TPS). In this report, five different transport solutions such as monorail, drag chain conveyor, and Automated Guided Vehicles, are compared with each other based on various aspects identified during the implementation process. Examples of these aspects include expansion possibilities, safety, and ergonomics. Each transport system was evaluated and compared in a table, scored on a scale of 1-5 based on these aspects. The two systems that were considered most suitable were selected for further comparison. The project was limited to addressing only the transport system itself, excluding layout proposals or logistics. The result indicate that an Automated Guided Vehicle system is the most optimal transport solution for the assembly line. Further work on the project should include a cost comparison of the different transport solutions, as well as a deeper analysis of their integration with existing systems. / Ålö AB är ett världsledande företag inom jordbruksredskap. De säljer och tillverkar frontlastare och redskapslösningar till traktorer. Transportlösningen som används på monteringen idag är gammal och måste bytas ut inom en snar framtid. Syftet med projektet var att genomföra en förundersökning som kan bidra med ökade kunskaper inför kommande beslut om implementering av ett nytt transportsystem. Genomförandet av undersökningen bygger på en litteraturstudie och observation av befintligt transportsystem. Även en marknadsundersökning över transportsystem har gjorts. Arbetet utgår från teorier som 5s och Toyota Production system. Fem olika transportlösningar, exempelvis monorail, drag chain conveyor och Automated Guided Vehicles, jämförs med varandra och diskuteras utifrån aspekter som tagits fram under genomförandet. Exempel på aspekterna är utbyggnadsmöjligheter, säkerhet och ergonomi. Aspekterna poängsattes på en skala 1–5. De två system som ansågs mest lämpade valdes ut för en vidare jämförelse. Projektet avgränsades till att endast behandla själva transportsystemet, inte layoutförslag eller logistik. Resultatet visar att ett Automated Guided Vehicle system är det mest optimala transportsystemet för monteringslinan. Fortsatt arbete med projektet borde inkludera en jämförelse av kostnaderna för de olika transportlösningarna. Samt en djupare analys av deras integrering med befintliga system.

Optimal intercept trajectories for a boost-sustain-coast medium-range air-to-air missile are synthesized using optimal control theory. Optimality in time/range/energy at intercept of a target is the main objective. Attainable sets and their boundaries are obtained and used to generate optimal intercept points in a three-dimensional scenario. A three-phase closed-loop guidance scheme is used to generate an efficient guidance law against a maneuvering target. In the present study, target maneuvers are restricted to the horizontal plane. An initial boost-phase with near-optimal guidance in the presence of active control constraints and thrust switches is simulated. Target maneuvers are neglected during this phase. A new method of gain evaluation is detailed. A midcourse guidance scheme with neighboring guidance, transversal comparisons, and chasing center-of-attainability of target to augment performance is studied. Modifications in terminal guidance using proportional navigation, such as chasing the center-of-attainability of target, altitude shaping, and drag-resolution schemes are used to attempt better performance at intercept. A composite guidance strategy using a combination of neighboring guidance and proportional navigation for the midcourse guidance is introduced. The excellent performance of this guidance strategy and the improvement in storage requirements for on-board use make it a very special scheme. / Ph. D.

O aumento no número de dispositivos móveis com crescente capacidade de processamento traz como incentivo o desenvolvimento de sistemas distribuídos que possam explorar estas novas tecnologias. Dentro dos sistemas distribuídos, os mecanismos que permitem a troca de dados entre os processos que o constituem, possuem um papel importante para o desempenho da aplicação. Uma abordagem interessante para implementar estes mecanismos é por meio do uso de middlewares. O middleware abstrai as funcionalidades básicas oferecidas pelo sistema operacional e hardware para oferecer serviços de alto nível aos desenvolvedores. Estes serviços permitem aos desenvolvedores se concentrarem somente na lógica interna de suas aplicações, reduzindo também seu custo de manutenção. Incentivado pela necessidade de um mecanismo que garantisse a troca de informações entre as unidades de um sistema autônomo para o gerenciamento de AGVs (Automated Guided Vehicle), desenvolvido pelo grupo de mecatrônica da Universidade de São Paulo, este trabalho propõe uma arquitetura de comunicação baseada em middlewares que é inspirada no paradigma de comunicação RMI (Remote Method Invocation) para suprir a troca de dados necessária por meio do conceito de objetos distribuídos. Para apresentar o uso da IDL (Interface Definition Language) disponibilizada pela arquitetura proposta, uma demonstração de como acrescentar novos serviços à arquitetura é descrita. Para avaliar o desempenho da arquitetura e analisar o comportamento dos serviços oferecidos, testes de tempo de resposta, throughput e disponibilidade foram realizados. Pode-se verificar que a arquitetura proposta, além de apresentar um desempenho satisfatório para a operação do sistema de AGVs, proporcionou uma estrutura que pode ser facilmente adaptada para futuras alterações no projeto sem modificar diretamente as definições da arquitetura de comunicação. / The increase in the process capacity of mobile devices has motivated the development of distributed applications that exploit new technologies. In distributed applications, the mechanisms that enable the exchange of data among the application processes play an important role in their performance. An interesting way to deal with such an exchange is to adopt middleware to handle communication. The middleware abstracts the functionalities provided by the underlying operational system and hardware and offers a set of high-level services, which assist developers in working directly with the logic of the application and reducing its maintenance costs. Motivated by the necessity of a mechanism that ensures the exchange of information among the units of an AGV (Automated Guided Vehicle) system designed by the University of São Paulo, this dissertation develops a communication architecture based on middleware. The architecture is inspired in the RMI (Remote Method Invocation) paradigm to enable the data exchange based on the concept of distributed objects. An IDL (Interface Definition Language) was conceived for the architecture and a demonstration of how new services can be added to the structure was conducted. To validate the performance of the proposed middleware and its services, tests of network response time, throughput and availability were carried out. The architecture showed a satisfactory performance for the operation of the AGV system and provided a structure that can be easily adapted for future changes in the project.

O aumento no número de dispositivos móveis com crescente capacidade de processamento traz como incentivo o desenvolvimento de sistemas distribuídos que possam explorar estas novas tecnologias. Dentro dos sistemas distribuídos, os mecanismos que permitem a troca de dados entre os processos que o constituem, possuem um papel importante para o desempenho da aplicação. Uma abordagem interessante para implementar estes mecanismos é por meio do uso de middlewares. O middleware abstrai as funcionalidades básicas oferecidas pelo sistema operacional e hardware para oferecer serviços de alto nível aos desenvolvedores. Estes serviços permitem aos desenvolvedores se concentrarem somente na lógica interna de suas aplicações, reduzindo também seu custo de manutenção. Incentivado pela necessidade de um mecanismo que garantisse a troca de informações entre as unidades de um sistema autônomo para o gerenciamento de AGVs (Automated Guided Vehicle), desenvolvido pelo grupo de mecatrônica da Universidade de São Paulo, este trabalho propõe uma arquitetura de comunicação baseada em middlewares que é inspirada no paradigma de comunicação RMI (Remote Method Invocation) para suprir a troca de dados necessária por meio do conceito de objetos distribuídos. Para apresentar o uso da IDL (Interface Definition Language) disponibilizada pela arquitetura proposta, uma demonstração de como acrescentar novos serviços à arquitetura é descrita. Para avaliar o desempenho da arquitetura e analisar o comportamento dos serviços oferecidos, testes de tempo de resposta, throughput e disponibilidade foram realizados. Pode-se verificar que a arquitetura proposta, além de apresentar um desempenho satisfatório para a operação do sistema de AGVs, proporcionou uma estrutura que pode ser facilmente adaptada para futuras alterações no projeto sem modificar diretamente as definições da arquitetura de comunicação. / The increase in the process capacity of mobile devices has motivated the development of distributed applications that exploit new technologies. In distributed applications, the mechanisms that enable the exchange of data among the application processes play an important role in their performance. An interesting way to deal with such an exchange is to adopt middleware to handle communication. The middleware abstracts the functionalities provided by the underlying operational system and hardware and offers a set of high-level services, which assist developers in working directly with the logic of the application and reducing its maintenance costs. Motivated by the necessity of a mechanism that ensures the exchange of information among the units of an AGV (Automated Guided Vehicle) system designed by the University of São Paulo, this dissertation develops a communication architecture based on middleware. The architecture is inspired in the RMI (Remote Method Invocation) paradigm to enable the data exchange based on the concept of distributed objects. An IDL (Interface Definition Language) was conceived for the architecture and a demonstration of how new services can be added to the structure was conducted. To validate the performance of the proposed middleware and its services, tests of network response time, throughput and availability were carried out. The architecture showed a satisfactory performance for the operation of the AGV system and provided a structure that can be easily adapted for future changes in the project.

Thesis (MEd (Curriculum Studies)--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Given that the South African government intends to improve its literacy rates by implementing Guided Reading in the primary schools, teachers are challenged to give good quality Guided Reading instruction. This study evaluates how teachers understand and implement Guided Reading in Grade 1 and 2 at three public schools in the Western Cape. It discusses how Guided Reading can be a teaching context in which children learn to construct meaning independently from text. In addition, the study gives explanation on how to implement Guided Reading into classrooms. To gather data on teachers’ current understanding and implementation of Guided Reading, a Guided Reading Self-Assessment Inventory was used (Fountas & Pinnell 1996:283-285). Data were also drawn from observations of teachers during their Guided Reading instruction. Analysis of the abovementioned quantitative and qualitative research data, indicate that teachers have a superficial understanding of Guided Reading. The new policy requirements for Guided Reading appear to fail to offer teachers a sufficient explanation of Guided Reading. Without clear explanation of Guided Reading and practical support, it is expected that South African teachers will continue with their traditional reading instruction, because they do not fully understand the concept and value of Guided Reading. This study suggests that South African teachers struggle to implement Guided Reading in their classrooms, because they do not create Guided Reading groups based on ongoing assessment and they do not have access to leveled Guided Reading books. Without addressing these basic requirements, it is unlikely that Guided Reading will be implemented with any success in South African classrooms. An overriding conclusion is that Guided Reading instruction needs further research before it can be implemented correctly on a large scale in the primary schools of South Africa. / AFRIKAANSE OPSOMMING: Die Suid Afrikaanse regering se besluit om begeleide lees “Guided Reading” in primêre skole te implimenteer om gelettertheid te bevorder, plaas ‘n groot verantwoordelikheid op onderwysers om hierdie leesbenadering op die juiste manier aan te bied. Hierdie navorsing fokus op Graad 1- en 2- onderwysers se begrip en uitvoering van begeleide lees in drie publieke skole in die Wes-Kaap. Die studie poog om onderwysers bewus te maak dat begeleide lees ‘n raamwerk kan wees waarbinne kinders leer om met begrip te lees asook om hoe hierdie leesbenadering te implementeer. Om data in te samel oor die huidige stand van uitvoering van begeleidelees is gebruik gemaak van ‘n “Guided Reading Self-Assessment Inventory” (Fountas & Pinnell 1996:283-285). Waarnemings is ook gemaak van onderwysers se begeleide lees onderrig. Die analisering van die data dui op Suid Afrikaanse onderwysers se gebrekkige begrip van begeleide lees, tot ‘n mate as gevolg van onduidelike beleidsdokumente. Sonder duidelike instruksie en ondersteuning aan onderwysers is dit te verwagte dat hulle sal terugval op hul tradisionele onderrigmetodes, terwyl die volle waarde van begeleide lees hulle ontgaan. Die studie bevind dat onderwysers die leesbenadering nie korrek tot uitvoering kan bring nie omdat hulle nie hul kinders in groepe plaas aan die hand van deurlopende evaluering nie, maar ook weens ‘n tekort aan geskikte onderrigmateriaal. Die sukses van begeleide lees is onwaarskynlik indien hierdie tekorte nie aangespreek word nie. Die oorheersende slotsom van die studie is dat verdere navorsing in die onderrig van begeleide lees nodig is voordat dit op groot skaal ingestel kan word by alle primêre skole in Suid Afrika.

No description available.

Magnetic Resonance Imaging (MRI) provides unique advantages such as superior soft tissue contrast, true multiplanar imaging, variable contrast mechanisms, measurement of temperature changes, perfusion and diffusion, and no ionizing radiation. Despite considerable research efforts in the field of interventional MRI, numerous challenges remain including restricted access to the patient, high acoustic noise and a shortage of MRI-safe devices. Novel methods and devices are presented in this thesis with the primary objective of enabling effective MRI-guided interventions, particularly abdominal needle and common catheter-based endovascular interventions. Firstly, a set of MRI-safe devices (guidewires, micro guidewires, catheters and micro catheters) were developed with passive or inductively coupling resonant markers for MRI visualisation. Secondly, a method was implemented for wireless tracking and dynamic guidance of instruments. Thirdly, a framework of technologies was developed for in-room display, wireless MRI remote control and multi-user communication along with a dedicated user interface and imaging protocol. These implementations were assessed in regards to MRI-safety, performance and usability and evaluated for MRI-guided liver biopsies, balloon angioplasty procedures and also for mechanical thrombolysis. Flow phantoms, Thiel soft-embalmed human cadavers with partially re-established perfusion and a porcine model were used for in vitro, ex vivo and in vivo validation, respectively. The results demonstrate that these interventions are experimentally feasible and practical when using the presented developments: automated device tracking and equipment designed for MRI-guided interventions streamlined procedural workflow. Specifically, it was shown that fast and accurate needle placements along complex trajectories were feasible using a wireless interactive display and control device with a dedicated user interface for interventions. Moreover, safe and efficacious balloon angioplasties of the iliac artery were practical using the described framework of technologies along with a dedicated MRI protocol. Finally, it was demonstrated that these developments could be adapted and applied to MRI-guided endovascular mechanical thrombolysis of the middle cerebral artery. The technologies, described in this thesis have been shown to overcome many of the present limitations and should therefore be useful for enabling MRI-guided interventions while not further constraining the operating physician in an already complex environment. Nevertheless, it is acknowledged that many crucial issues remain to be solved in the field of iMRI and in the context of the presented research. In particular further device optimisations, improvements of the tracking implementation along with further in vivo evaluations are required before moving towards clinical evaluation. This thesis sets the groundwork for moving ahead with the eventual clinical realisation of optimised MRI-guided interventions.