Thesis (Ph. D., Information and Computer Science)--University of California, Irvine, 1997. / Includes bibliographical references.

Thesis (MPh)--University of Melbourne, Dept. of Physics, 2010. / Typescript. Includes bibliographical references (p. 77-83)

by Michael Athans. / "November 30, 1978." Caption title. / Travel support provided in part by National Science Foundation Grant NSF/ENG77-07777

Στην εργασία αυτή μελετώνται τεχνικές διόρθωσης λαθών BCH κωδικοποίησης και η υλοποίηση τους με αρχιτεκτονικές VLSI. Στην αρχή γίνεται μία εισαγωγή στα Συστήματα Ψηφιακής Επικοινωνίας. Αυτή ακολουθείται από μία περιγραφή των μαθηματικών θεωρημάτων και ορισμών που χρησιμοποιούνται για την Διόρθωση Λαθών. Επίσης, παρουσιάζονται οι βασικές Τεχνικές Κωδικοποίησης, δίνοντας ιδιαίτερη έμφαση στην BCH Κωδικοποίηση. Στην συνέχεια παρουσιάζεται η πλατφόρμα εξομοίωσης στο MatLab, και οι συναρτήσεις που την υλοποιούν, για την μέτρηση BER διαφόρων BCH Κωδικών. Κάνοντας χρήση αυτής της πλατφόρμας γίνεται η σύγκριση μεταξύ non-binary και binary BCH Κωδίκων ίδιου code rate καθώς και non-binary BCH Κωδίκων διαφορετικών μηκών και code rate. Στο τελευταίο μέρος της εργασίας, προτείνεται μία γενική αρχιτεκτονική ενός non-binary BCH αποκωδικοποιητή. Βάσει αυτής της προτεινόμενης αρχιτεκτονικής περιγράφεται λεπτομερώς η υλοποίηση ενός αποκωδικοποιητή οκταδικού BCH Κώδικα μήκους 63 συμβόλων και διάστασης 48 συμβόλων με απόσταση σχεδίασης 4 συμβόλων. Τέλος, μετά την παρουσίαση των αποτελεσμάτων της υλοποίησης του συγκεκριμένου αποκωδικοποιητή σε FPGA πλατφόρμα ανάπτυξης, συνοψίζονται τα συμπεράσματα που προέκυψαν από την παραπάνω διαδικασία. / This dissertation refers to BCH error correction coding techniques and their implementation with VLSI architectures. At first, an introduction in the Digital Communications Systems takes place. This is followed by a description of mathematical theorems and definitions used for the error correction coding. In addition, basic coding techniques are presented emphasising in BCH Codes. The dissertation continues with the presentation of the MatLab simulation platform, as well as the functions that implement this, for the BER measurement of various BCH codes. Using this platform, a comparison is made between non binary and binary BCH codes of the same code rate as well as non binary BCH codes of different lengths and code rates. In the last part, a general architecture of a non binary BCH decoder is proposed. According to this architecture, an implementation of an octal BCH 63 symbols length, 48 symbol dimension and 4 symbols design distance code decoder, is described in depth. Finally, after the presentation of the implementation results of the described decoder in FPGA board, the conclusions that came up from the above procedure, are summarised.

Στην παρούσα διπλωματική εργασία μελετάται και παρουσιάζεται μια μεγάλη βιομηχανική μονάδα παραγωγής κεραμιδιών. Ειδική μελέτη εκπονείται για το βιομηχανικό φούρνο μεγάλης κλίμακας, για τον οποίο παρουσιάζονται μαθηματικά μοντέλα που εξομοιώνουν τη λειτουργία του. Ολόκληρη η παραγωγική διαδικασία εξομοιώνεται σε ένα τρισδιάστατο μοντέλο σε περιβάλλον SIMIO. Στη συνέχεια μελετάται η συμπεριφορά του μοντέλου σε διάφορες καταστάσεις λειτουργίας, εξάγονται συμπεράσματα από αυτό και δίνονται παραδείγματα της χρηστικότητας της συγκεκριμένης εξομοίωσης για βελτίωση σε θέματα που αφορούν την οργάνωση της παραγωγής. / In the present thesis a large industrial plant of tiles production is being studied and presented. Special study is prepared for the industrial large scale oven for whom are presented mathematical models which simulate its operation. The entire production process is simulated in a three-dimensional model in the environment of SIMIO. Then we study the behavior of the model in different modes, draw conclusions from it, and give examples of the utility of this simulation for improvement in matters concerning the organization of production.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Project management (PM) is a very important field in engineering as a whole. The management of most projects has become more complex in recent times, due to greater technical complexity and the requirement of diversified skills. The management of risks is a very important process to improve the performance of a project. This is due to the link between project risks and objectives. However, this aspect of PM becomes increasingly more difficult to manage with increasing project complexity. For these reasons a need exists for more efficient PM methods. This thesis had three objectives. The first was to understand the processes and principles of PM, systems engineering (SE) and risk management. This was achieved by doing a literature study on the three fields. The second objective was to identify areas of greater risk within the management of projects. The final objective was to develop an effective generic model that illustrates the integration of SE principles into PM, with the goal to reduce the identified risks. Five risks were identified during this research. They were considered to be the most important in project management. This was accomplished by means of a questionnaire that was sent out to experts in the industry. It was established from this investigation that the following five risks, in order of importance, pose the biggest threat to the success of a project: 1. Poorly defined requirements; 2. Poor communication; 3. Poor risk management; 4. Lack of customer involvement; and 5. Inaccurate estimates. These risks were addressed by integrating the principles of SE into PM. SE is an iterative process that needs a diverse set of people, with a variety of skills, to achieve customer requirements. Various SE approaches and strategies were developed throughout the years. They were investigated to obtain insight into which of them can be used to improve PM. The top-down iterative development principles of SE offer a great advantage, and therefore it was appropriate to integrate these principles into PM. A model was developed as part of this thesis to illustrate the integration of SE principles into PM, and the importance of risk management. The model was named “Project Management Integrated with Systems Engineering Principles Model”. This tool can be used by engineers and their project teams to enhance the management of projects. It is also a generic tool that can be used for any project. The final step of this research was the validation of the model. This was done by means of expert evaluation. The purpose of this validation was to test whether the objectives of the research were met, and if the model was valid in the sense of ease of use and usefulness. The final objective of the validation process was to determine if the integration of systems engineering (SE) principles into project management (PM) were successful, and if it will reduce risks in large scale projects. It was concluded from this evaluation that its objectives were met and that the model successfully demonstrated the integration of SE into PM to reduce risks in large scale projects. Several recommendations were made that may enhance this study. They main recommendations are: 1. Researching the impact of communication on projects, by using case studies. 2. SE principles are mainly used in the first two phases of the model. Further investigation of using SE principles in phase three may be researched. 3. Customer involvement may be used during changes in the project. For this reason it is recommended that future studies may include investigation of the impact the customer has on project changes and the change management process. 4. The model could be tested in the industry on an active project. This will greatly improve the validity of the model. / AFRIKAANSE OPSOMMING: Projekbestuur is ‘n baie belangrike veld in ingenieurswese as geheel. As gevolg van die toenemende tegniese kompleksiteit en die vereiste van verskillende vaardighede, het die bestuur van meeste projekte meer gekompliseerd geraak met tyd. Die bestuur van risiko’s is ‘n baie belangrike proses om die uitvoering van ‘n projek te verbeter. Hierdie aspek van projekbestuur het egter al hoe moeiliker geword om te bestuur. Dus hiervoor bestaan daar ‘n behoefte vir meer doeltreffende projekbestuur metodes. Hierdie tesis het drie doelwitte gehad. Die eerste doelwit was om die prosesse en beginsels van projekbestuur, stelsels ingenieurswese en risikobestuur te verstaan. Dit was bevredig deur ‘n literatuur studie wat gedoen is in die drie velde. Die tweede doelwit was gestel om die areas van groter risiko binne die bestuur van projekte te identifiseer. Die finale doelwit was die ontwilkkeling van ‘n effektiewe generiese model wat die integrasie van stelsels ingenieurswese beginsels binne projekbestuur demonstreer, met die doel om die geïdentifiseerde risiko’s te verminder. Vyf risiko’s, wat as die mees belangrikste in projekbestuur beskou word, was geïdentifiseer. Hierdie risiko’s was deur middel van ‘n vraelys, wat aan deskundiges in die industrie gestuur was, geïdentifiseer. Die risiko’s, gelys in volgorde van belangrikheid, was: 1. Swak bepaalde vereistes; 2. Swak kommunikasie; 3. Swak risiko bestuur; 4. Onnoukeurige skattings; en 5. Geen kliënt betrokkenheid. Vervolgens was hierdie risiko’s deur die integrasie van stelsels ingenieurswese beginsels in projekbestuur toegespreek. Stelsels ingenieurswese is ‘n herhalingsproses wat die kliënt se vereistes bevredig, deur gebruik te maak van ‘n diverse groep mense met ‘n verskeidenheid van vaardighede. Verskeie stelsels ingenieurswese benaderings en strategië is deur die jare ontwikkel. Hierdie benaderings en strategië was geondersoek om vas te stel watter van hulle toegepas kan word om projekbestuur te verbeter. Die “top-down” herhalende ontwikkeling beginsels van stelsels ingenieurswese bied ‘n groot voordeel, en dit was om hierdie rede toepaslik om dié beginsels in projekbestuur te integreer. ‘n Model was ontwikkel as deel van die navorsing om die integrasie van stelsels ingenieurswese beginsels binne projekbestuur te illustreer, asook die belangrikheid van risikobestuur. Die model is genoem “Project Management Integrated with Systems Engineering Principles Model”. Hierdie model kan deur ingenieurs en hul projekspanne gebruik word om die bestuur van projekte te versterk. Die finale stap van die navorsing was die evaluasie van die model. Dit was gedoen deur middel van deskundige evaluasie. Die validasie proses het twee doelwitte gehad. Die eerste doel was om te bepaal of die doelwitte van die ondersoek bereik was, asook om vas te stel of die model geldig was in die sin van gemak van gebruik en bruikbaarheid. Die tweede doel van die validasie proses was om te bepaal of die model suksesvol die integrasie van stelsels ingenieurswese binne projekbestuur gedemonstreer het, en of hierdie integrasie risiko’s in groot skaalse projekte sal verminder. Dit was afgelei van die evaluasie dat die model wel suksesvol die integrasie van stelsels ingenieurswese binne projekbestuur demonstreer om risiko’s in grootskaalse projekte te verminder. Verskeie aanbevelings was gemaak wat hierdie navorsing kan versterk in waarde. Die hoof aanbevelings was: 1. Die impak wat kommunikasie op projekte het kan geondersoek word deur middel van gevallestudies. 2. Stelsels ingenieurswese beginsels is hoofsaaklik gedurende die eerste twee fases van die model gebruik. Die gebruik van stelsels ingenieurswese beginsels in fase drie kan verder ondersoek word. 3. Kliënt betrokkenheid gedurende veranderinge in ‘n projek kan gebruik word. Om hierdie rede word dit aanbeveel dat verdere studies die kliënt se impak op projek veranderings en verandering in bestuursproses ondersoek word. 4. Die model kan getoets word in die industrie op ‘n aktiewe projek. Dit sal die geldigheid van die model grootliks verbeter.

abstract: K-Nearest-Neighbors (KNN) search is a fundamental problem in many application domains such as database and data mining, information retrieval, machine learning, pattern recognition and plagiarism detection. Locality sensitive hash (LSH) is so far the most practical approximate KNN search algorithm for high dimensional data. Algorithms such as Multi-Probe LSH and LSH-Forest improve upon the basic LSH algorithm by varying hash bucket size dynamically at query time, so these two algorithms can answer different KNN queries adaptively. However, these two algorithms need a data access post-processing step after candidates' collection in order to get the final answer to the KNN query. In this thesis, Multi-Probe LSH with data access post-processing (Multi-Probe LSH with DAPP) algorithm and LSH-Forest with data access post-processing (LSH-Forest with DAPP) algorithm are improved by replacing the costly data access post-processing (DAPP) step with a much faster histogram-based post-processing (HBPP). Two HBPP algorithms: LSH-Forest with HBPP and Multi- Probe LSH with HBPP are presented in this thesis, both of them achieve the three goals for KNN search in large scale high dimensional data set: high search quality, high time efficiency, high space efficiency. None of the previous KNN algorithms can achieve all three goals. More specifically, it is shown that HBPP algorithms can always achieve high search quality (as good as LSH-Forest with DAPP and Multi-Probe LSH with DAPP) with much less time cost (one to several orders of magnitude speedup) and same memory usage. It is also shown that with almost same time cost and memory usage, HBPP algorithms can always achieve better search quality than LSH-Forest with random pick (LSH-Forest with RP) and Multi-Probe LSH with random pick (Multi-Probe LSH with RP). Moreover, to achieve a very high search quality, Multi-Probe with HBPP is always a better choice than LSH-Forest with HBPP, regardless of the distribution, size and dimension number of the data set. / Dissertation/Thesis / M.S. Computer Science 2011

Esta tese tem como objetivo analisar as ações do Estado brasileiro na educação básica no período de 1995 a 2014. Para tanto, faço uso de uma política pública educacional – o Sistema de Avaliação da Educação Básica (Saeb) – como “janela” desta pesquisa. O uso de uma política educacional como “janela” implica no entendimento de que as políticas públicas estão inseparavelmente relacionadas ao Estado (AGUDELO, 2011; OSCAR OSZLAK; GUILLERMO O'DONNELL, 1995) e que só se pode definir como política pública a ação que tem o aval estatal (OSZLAK; O'DONNELL, 1995). A escolha do Saeb, por sua vez, esteve alicerçada em uma revisão bibliográfica que aponta que, a partir das reformas estatais dos anos de 1990, as avaliações ganharam centralidade no cenário brasileiro (HYPOLITO, 2008; PERONI, 2003; FREITAS, 2004; BONAMINO; SOUSA, 2012; SOUZA; OLIVEIRA, 2003; COELHO, 2008). Esta é a justificativa para fazer uso de uma política pública educacional que inclui avaliações de larga escala, pois entendo que, olhando para tais avaliações, posso ter um acesso privilegiado para identificar como o Estado age na educação básica. A revisão bibliográfica também apontou que as reformas estatais de 1990 no Brasil foram fortemente influenciadas pelo modelo gerencial. Assim, os pressupostos gerencialistas foram aqueles, centralmente, utilizados para o entendimento das mudanças ocorridas no Estado brasileiro na década de 1990. Como forma de entender o modelo gerencial, faço uso das contribuições dos autores John Clarke e Janet Newman – que estudaram as reformas gerenciais no contexto da Inglaterra. Apresento um breve panorama histórico dos contextos internacional e brasileiro, no qual trato sobre a reestruturação do Estado e as principais mudanças que passaram a existir em relação às políticas educacionais, examinando, de forma especial, a centralidade que ganharam as avaliações de larga escala na educação. Através da realização de entrevistas realistas (PAWSON; TILLEY, 2000) com pessoas ligadas a órgãos estatais e a instituições não-estatais – que têm exercido um importante papel nas discussões educacionais –, da análise de documentos e da teoria construída para a tese, realizei uma análise que levou em conta as lentes teóricas utilizadas ao longo do estudo – análise relacional (APPLE, 2006) e a abordagem estratégico-relacional (JESSOP, 2008) – e que permitiu inferir, de forma complexa, sobre como se caracterizam as ações do Estado brasileiro na educação básica no período de 1995 a 2014. Concluí que, apesar da existência de particularidades no âmbito estatal brasileiro, sendo o Estado ainda forte e bastante centralizado e caracterizado pelo patrimonialismo, coronelismo e populismo (FAORO, 2001), as avaliações de larga escala e os pressupostos gerenciais servem como importantes orientadores das ações do Estado na educação básica, o que corrobora o alerta de Clarke e Newman (1997) de que, apesar das contradições existentes no Estado, o gerencialismo possui, atualmente, primazia sobre outros modelos. / This dissertation aims to analyze the action of the Brazilian State in the context of basic education from 1995 to 2014. Therefore, I use a public educational policy – the Basic Education Assessment System – as a “window” of this research. The use of a educational policy as a “window” implies the understanding that public policies are inseparably related to the State (HYPOLITO, 2008; PERONI, 2003; FREITAS, 2004; BONAMINO; SOUSA, 2012; SOUZA; OLIVEIRA, 2003; COELHO, 2008) and also requires the understanding that a policy can only be set as public policy when it has the State guarantee (OSZLAK; O'DONNELL, 1995). The choice of the Basic Education Assessment System was based on the literature review that points out that evaluations gained centrality in the Brazilian context since the State reforms in the 1990s (HYPOLITO, 2008; PERONI, 2003; FREITAS, 2004; BONAMINO; SOUSA, 2012; SOUZA; OLIVEIRA, 2003; COELHO, 2008). This is the justification for using an educational policy that includes large-scale assessments; I understand that, when looking for such assessments, I can have a privileged access to identify how the State acts in basic education. The literature review also pointed out that in the 1990s the State reform in Brazil was strongly influenced by managerialism. Thus, managerial assumptions were used to understand the changes in the Brazilian State in the 1990s. In order to understand managerialism, I use the contributions from John Clarke and Janet Newman – who have studied managerial reforms in England’s context. I present a brief historical overview of both international and Brazilian contexts, in which I deal with the restructuring of the State and the major changes in relation to educational policies, examining, specially, the centrality of large-scale assessments in education. By conducting realistic interviews (PAWSON; TILLEY, 2000) with people linked to State agencies and non-state institutions – which have played an important role in educational discussions –, document analysis and the theory built in this dissertation, I carried out an analysis that took into account the theoretical lens used throughout the study – relational analysis (APPLE, 2006) and the strategic-relational approach (JESSOP, 2008) – which allowed me to infer, in a complex way, how the action of the Brazilian State in basic education from 1995 to 2014 is characterized. I concluded that, despite of the existence of peculiarities in the Brazilian State level, which means that the State is still strong and quite centralized and characterized by paternalism, “coronelismo” and populism (FAORO, 2001), large-scale assessments and managerial assumptions have served as important guides of the State's actions in basic education, which confirms the Clarke and Newman’s alert (1997) that, in spite of the existence of contradictions in the State, managerialism has primacy over other models nowadays.

This qualitative study examines the connections between teachers’ views of large-scale assessment and their classroom practice, based on a case study of Ontario teachers and the Ontario Education Quality and Accountability Office [EQAO] Grade 9 Applied Assessment of Mathematics. Large-scale assessments are a prominent aspect of the Ontario education system; given that they are also mandatory, it is imperative that their impact on teaching be documented. This study enriches the existing literature on the topic of the Grade 9 EQAO Assessment of Mathematics, and provides a more-recent portrayal of the teachers’ views of this assessment and the potential impact of these views on classroom teaching by highlighting teacher attitudes, concerns, and classroom practices.

The purpose of this thesis was to visualize the 1.7 billion stars released by the European Space Agency, as the second data release (DR2) of their Gaia mission, in the open source software OpenSpace with interactive framerates and also to be able to filter the data in real-time. An additional implementation goal was to streamline the data pipeline so that astronomers could use OpenSpace as a visualization tool in their research. An out-of-core rendering technique has been implemented where the data is streamed from disk during runtime. To be able to stream the data it first has to be read, sorted into an octree structure and then stored as binary files in a preprocess. The results of this report show that the entire DR2 dataset can be read from multiple files in a folder and stored as binary values in about seven hours. This step determines what values the user will be able to filter by and only has to be done once for a specific dataset. Then an octree can be created in about 5 to 60 minutes where the user can define if the stars should be filtered by any of the previously stored values. Only values used in the rendering will be stored in the octree. If the created octree can fit in the computer’s working memory then the entire octree will be loaded asynchronously on start-up otherwise only a binary file with the structure of the octree will be read during start-up while the actual star data will be streamed from disk during runtime. When the data have been loaded it is streamed to the GPU. Only stars that are visible are uploaded and the application also keeps track of which nodes that already have been uploaded to eliminate redundant updates. The inner nodes of the octree store the brightest stars in all its descendants as a level-of-detail cache that can be used when the nodes are small enough in screen space. The previous star rendering in OpenSpace has been improved by dividing the rendering phase into two passes. The first pass renders into a framebuffer object while the second pass then performs a tonemapping of the values. The rendering can be done either with billboard instancing or point splatting. The latter is generally the faster alternative. The user can also switch between using VBOs or SSBOs when updating the buffers. The latter is faster but requires OpenGL 4.3, which Apple products do not currently support. The rendering runs with interactive framerates for both flat and curved screen, such as domes/planetariums. The user can also switch dataset during render as well as render technique, buffer objects, color settings and many other properties. It is also possible to turn time on and see the stars move with their calculated space velocity, or transverse velocity if the star lacks radial velocity measurements. The calculations omits the gravitational rotation. The purpose of the thesis has been fulfilled as it is possible to fly through the entire DR2 dataset on a moderate desktop computer and filter the data in real-time. However, the main contribution of the project may be that the ground work has been laid in OpenSpace for astronomers to actually use it as a tool when visualizing their own datasets and also for continuing to explore the coming Gaia releases.