This dissertation presents the exploration of two fiber optics techniques involving high power pulse laser delivery. The first research topic is "Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments", which uses the fiber delivered pulse laser for acoustic generation. The second research topic is "Fiber Optics Guided Laser Micromachining", which uses the fiber delivered pulse laser for material ablation. The objective of the first research topic is to develop a first-of-a-kind technology for remote fiber optic generation and detection of acoustic waves for structural health monitoring in harsh environments. Three different acoustic generation mechanisms were studied in detail, including laser induced plasma breakdown (LIB), Erbium-doped fiber laser absorption, and metal laser absorption. By comparing the performance of the acoustic generation units built based on these three mechanisms, the metal laser absorption method was selected to build a complete fiber optic structure health monitoring (FO-SHM) system. Based on the simulation results of elastic wave propagation and fiber Bragg grating acoustic pulse detection, an FO-SHM sensing system was designed and built. This system was first tested on an aluminum piece in the room temperature range and successfully demonstrated its capability of multi-parameter monitoring and multi-point sensing. With additional studies, the upgraded FO-SHM element was successfully demonstrated at high temperatures up to 600oC on P-91 high temperature steels. During the studies of high power pulse laser delivery, it was discovered that with proper laser-to-fiber coupling, the output laser from a multimode fiber can directly ablate materials around the fiber tip. Therefore, it is possible to use a fiber-guided laser beam instead of free space laser beams for micromachining, and this solves the aspect ratio limitation rooted in a traditional laser beam micromachining method. In this dissertation, this Guided Laser MicroMachining (GLMM) concept was developed and experimentally demonstrated by applying it to high aspect ratio micro-drilling. It was achieved that an aspect ratio of 40 on aluminum and an aspect ratio of 100 on PET, with a hole diameter less than 200 um. / PHD / This dissertation presents two research topics both related to high power laser and fiber optic. The first topic studies the application of using optical fiber and high power laser for ultrasonic non-destructive evaluation. The general idea is to use fiber optic to remotely generate and monitor ultrasonic waves on a workpiece. Due to the fact that there are no electronic components involved in the sensing part of the system, this system can work at high temperature and is unsusceptible to EMI. The second topic studies the usage of optical fiber in high aspect ratio micromachining. The key concept is to use a fiber tip and the output high power laser as a "drilling tip", which eliminate the aspect ratio limitation rooted in the traditional free-space laser micromachining method. With this concept and a demonstrative micromachining system, we achieved record-breaking aspect ratio on both aluminum and plastic.

Currently, many missile fire control systems use a three degree of freedom (3-DOF) trajectory model. The three degrees of freedom represent the linear motion of the missile in three dimensions. A 6-DOF model adds roll, pitch, and yaw, or angular motion in three dimensions to the first three degrees of freedom. Because more of the missile’s attributes are modeled, a 6-DOF model is more accurate than a 3-DOF model. For the same reason, a 3-DOF model is easier to develop and executes faster. Also, because a 3-DOF model ignores the seemingly random angular motion, the step sizes used to integrate 3-DOF models are larger. The goal of this project is to develop a 6-DOF re-entry model with the accuracy of a 6-DOF model with conventional equations of motion and computational speed at least comparable to the 3-DOF model. This can be achieved by transforming the equations that compute the effects of angular motion so that they are better conditioned. Essentially, this is done by fitting a sine wave to the oscillating state variables representing the orientation and angular rates, namely the quaternions and the angular velocity. This thesis shows the results of transforming the oscillating variables of the state vector. / Master of Science

The purpose of this research was to determine the feasibility of a laser-based positioning system as a primary navigation method. The system developed for this research consisted of an automated guided vehicle which navigated solely with the use of the laser-based positioning system in real-time. To date, there are no systems which can navigate a pre-defined path using such a positioning system. Some lessons were learned by the researcher, however, concerning the viability of this system in an industrial environment. The system should have had the following advantages over previous systems: 1) Greater range, 2) no prior structuring of environment, 3) real-time navigation, and 4) no reliance on dead-reckoning for navigation. The results showed that goals two through four had been met and are advantages of this system over current systems. The range of this system is limited, however, but it is believed that the next generation system should have greater range than the system used in this research. / Master of Science

A reduced order model describing the energy and heading angle dynamics of a scramjet missile is developed using a singular perturbation technique. The cruise analysis is briefly reviewed to determine the conditions at which the missile will cruise most efficiently. The turn and climb performance of the missile over the conditions of interest is then examined and a family of extremal trajectories is constructed which asymptotically approach the cruise at an intermediate altitude. / Master of Science

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.

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.

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