Optimization and Simulation of Manufacturing Systems

Production planning and scheduling are critical in matters of cost reduction and performance improvement, crucial factors due to the highly competitive nature of today's industry. The technological development allowed the emergence of hybrid methods of optimization and simulation to perform the referred actions with better results.The proposed method consists in the interaction between a Linear Programming model and a simulation model, being the latter used as an evaluator of the solution proposed by the first. In the case of an impossible solution, the simulation results will serve as input to the LP model to adjust some parameters in an intent to produce more realistic results. The proposed methodology was applied to a case study concerning a make-to-order company, JPM Indústria.The expected results should prove the proposed method to outperform other commonly used methods, and be satisfactory in handling the case study's problems, namely its bottleneck situation. Moreover, the results should support the proposed method as a viable alternative for production planning and scheduling problems

Corpus-Based Machine Translation : A Study Case for the e-Government of Costa Rica Corpus-Based Machine Translation: A Study Case for the e-Government of Costa Rica

Esta investigación pretende estudiar el estado del arte en las tecnologías de la traducción automática. Se explorará la teoría fundamental de los sistemas estadísticos basados en frases (PB-SMT) y neuronales (NMT): su arquitectura y funcionamiento. Luego, nos concentraremos en un caso de estudio que pondrá a prueba la capacidad del traductor para aprovechar al máximo el potencial de estas tecnologías. Este caso de estudio incita al traductor a poner en práctica todos sus conocimientos y habilidades profesionales para llevar a cabo la preparación de datos, entrenamiento, evaluación y ajuste de los motores.This research paper aims to approach the state-of-the-art technologies in machine translation. Following an overview of the architecture and mechanisms underpinning PB-SMT and NMT systems, we will focus on a specific use-case that would attest the translator's agency at maximizing the cutting-edge potential of these technologies, particularly the PB-SMT's capacity. The use-case urges the translator to dig out of his/her toolbox the best practices possible to improve the translation output text by means of data preparation, training, assessment and refinement tasks

Optimisations de compilateur optimistes pour les systèmes réseaux

Cette thèse présente un ensemble de techniques qui permettent l’optimisation des performances des sysèmes réseaux modernes. Ces techniques reposent sur l’analyse et la transformation des programmes impliqués dans la mise en ´oeuvre des protocoles réseaux. La première de ces techniques fait appel à la spécialisation de programmes pour optimiser des piles de protocoles r´eseaux. La deuxième, que nous avons nomm´ee sp´ecialisation distante, permet à des systèmes embarqu´es limit´es en ressources de b´en´eficier de la sp´ecialisation de programmes en d´eportant à travers le r´eseau les op´erations de sp´ecialisation à une machine distante moins limit´ee. La troisième propose un nouvel allocateur de m´emoire qui optimise l’utilisation des caches mat´eriels faite par un serveur r´eseau. Enfin, la quatrième technique utilise l’analyse de programmes statiques pour int´egrer l’allocateur propos´e dans un serveur réseau existant. On appelle ces techniques optimisations compilateur parce qu’elles opèrent sur le flot des donn´ees et du controle dans des programmes en les transformant pour qu’ils fonctionnent plus efficacement.This dissertation describes techniques that can optimize the performance of modernday network systems. They are applied through the analysis and transformation of programs that implement network protocols. The first of these techniques involves the use of Program Specialization, a well-established code-optimization approach, to optimize network protocol stacks. The second, Remote Specialization makes specialization amenable to resource-limited embedded systems by deferring it over the network to a more capable system. The third technique revolves around a novel memory manager introduced in this thesis and optimizes a network server’s use of the underlying hardware caches. Finally, the fourth technique uses static analysis to integrate the proposed memory manager with an existing network server. All four techniques are implemented in a set of tools that can be used to automatically optimize network applications, and are referred to as compiler optimizations as they are based on program analysis and transformation

Clustering and recommendation techniques for access control policy management

Managing access control policies can be a daunting process, given the frequent policy decisions that need to be made, and the potentially large number of policy rules involved. Policy management includes, but is not limited to: policy optimization, configuration, and analysis. Such tasks require a deep understanding of the policy and its building compo- nents, especially in scenarios where it frequently changes and needs to adapt to different environments. Assisting both administrators and users in performing these tasks is impor- tant in avoiding policy misconfigurations and ill-informed policy decisions. We investigate a number of clustering and recommendation techniques, and implement a set of tools that assist administrators and users in managing their policies. First, we propose and imple- ment an optimization technique, based on policy clustering and adaptable rule ranking, to achieve optimal request evaluation performance. Second, we implement a policy analysis framework that simplifies and visualizes analysis results, based on a hierarchical cluster- ing algorithm. The framework utilizes a similarity-based model that provides a basis of risk analysis on newly introduced policy rules. In addition to administrators, we focus on regular individuals whom nowadays manage their own access control polices on a regular basis. Users are making frequent policy decisions, especially with the increasing popular- ity of social network sites, such as Facebook and Twitter. For example, users are required to allow/deny access to their private data on social sites each time they install a 3rd party application. To make matters worse, 3rd party access requests are mostly uncustomizable by the user. We propose a framework that allows users to customize their policy decisions on social sites, and provides a set of recommendations that assist users in making well- informed decisions. Finally, as the browser has become the main medium for the users online presence, we investigate the access control models for 3rd party browser extensions. Even though, extensions enrich the browsing experience of users, they could potentially represent a threat to their privacy. We propose and implement a framework that 1) monitors 3rd party extension accesses, 2) provides fine-grained permission controls, and 3) Provides detailed permission information to users in effort to increase their privacy aware- ness. To evaluate the framework we conducted a within-subjects user study and found the framework to effectively increase user awareness of requested permissions

A performance management model for physical asset management

Thesis (MScEng)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Two fundamental aspects in modem business success are performance management and physical asset management. The current problem in the asset management environment is the lack of structured performance management, which is required to effectively control and enhance the dynamics of the asset and its life cycle. The result is ineffective assets with high life cycle costs, which will consequently influence the bottom line and return on investment, negatively. An Asset _eerformance Management Model (APM2 , pronounced A-P-M square) was developed. A sound theoretical foundation together with the experience of a leading asset management consultant resulted in the realization of a model that (i) gives a balanced view of asset performance, (ii) link asset performance to strategic business objectives, (iii) facilitates decision-making and problem solving, and (iv) enhances asset control and continuous improvement. The APM2 was developed by rese~ching and integrating five building blocks, which encompass the model requirements. The APM2 consists of two distinct components, namely: • the APM Reference Structure (APMRS), and • a range of APM Dockets. The APMRS is a basic structure that integrates the various building blocks into a framework for providing guidance and control, giving perspective on the entire model and explaining the high-level content of the model. It consists of five levels, each with a distinct focus: • Levell: Enterprise • Level2: Factory • Level3: Process Unit • Level4: Aggregate • Level5: Component The APM Dockets are a subset of the APMRS, where each level has a docket. These dockets are executable, unit-specific procedures, guiding and leading stakeholders towards improved asset performance. Also each of the five levels consists of six similar and inter-related elements. These elements are the foundation for each docket: lement 1: Stakeholders Element 2: Objectives Element 3: Measures Element 4: External Monitor & Targets Element 5: Responsibilities & Decision-Making Element 6: Control & Continuous Improvement Element 7 represents the link to the next level in the APM Reference Structure. • • • • • • Conclusively the APM2,s simplicity and understandability is realized through the APM Reference Structure, while the range of APM Dockets contribute to the practicality objective. The model has a strong theoretical foundation, but at the same time is generic, to be used in a wide range of industries. A leading asset management consultant plans to integrate the APM2 into their asset management program based on the thesis documentation. This application will test and validate the APM2 in practice. It is further recommended that an asset management program, with the associated APM2 , be used in conjunction with the Theory of Constraints and Total Productive Maintenance, because of obvious relationships. Further research is also suggested in relation with some of the experimental asset life cycle phases as well as certain financial considerations.AFRIKAANSE OPSOMMING: Twee fundamentele aspekte in hedendaagse besigheidsukses is prestasiebestuur and fisiese batebestuur. Die huidige probleem binne die batebestuursomgewing is die gebrek aan gestruktureerde prestasiebestuur, wat 'n vereiste is vir effektiewe beheer en verbeterings rondom die bate en sy lewensiklus. Die resultaat is oneffektiewe bates met hoë lewensikluskoste wat gevolglik wins en beleggingsopbrengs negatief beïnvloed. 'n Prestasiebestuur Model vir Bates (APM2, uitgespreek as A-P-M square) is ontwikkel. 'n Deeglike teoretiese fondasie tesame metdie ondervinding van vooraanstaande raadgewende batebestuurders, het die realisering van 'n model tot gevolg gehad, wat (i) bateprestasie gebalanseerd voorstel, (ii) bateprestasie met strategiese doelstellings verbind, (iii) besluitneming and probleemoplossing fasiliteer, en (iv) batekontrole en voortdurende verbetering bevorder. Die APM2 is ontwikkel deur middel van die identifisering en integrasie van vyf boustene wat die vereistes vir die modelomvat. Die APM2 bestaan onderskeidelik uit twee komponente, naamlik: • die APM Verwysingstruktuur (APMRS), en • 'n reeks APM Vouers. Die APMRS is 'n basiese struktuur wat die verskillende boustene binne 'n raamwerk integreer en sodoende leiding en beheer fasiliteer, die model as geheel in perspektief stel en die modelinhoud op hoë vlak verduidelik. Dit bestaan uit vyf vlakke, elk met 'n spesifieke fokus: • Vlak 1: Onderneming • Vlak2: Fabriek • Vlak 3: Proseseenheid • Vlak 4: Aggregaat • Vlak 5: Komponent Die APM Vouers is 'n subdeel van die APMRS, waar elke vlak 'n vouer het. Hierdie vouers is uitvoerbare, eenheid-spesifieke prosedures wat deelhebbers lei na beter bateprestasie. Ook bestaan elkeen van die vyf vlakke uit ses soortgelyke en inter-afhanklike elemente. Hierdie elemente is die fondasie vir elk van die vouers: • Element 1: Deelhebbers • Element 2: Doelwitte • Element 3: Metings • Element 4: Eksterne Monitering & Mikpunte • Element 5: Verantwoordelikhede & Besluitneming • Element 6: Kontrole & Voortdurende Verbetering • Element 7 stel die verbinding met die volgende vlak in die APM Verwysingstruktuur voor. Gevolglik word die eenvoud en verstaanbaarheid van die APM2 gerealiseer deur die APM Verwysingstruktuur, terwyl die reeks APM Vouers bydra tot die praktiese doelwit. Die model het 'n sterk teoretiese grondslag, maar terselfdertyd is dit generies, sodat dit in 'n wye spektrum van industrieë gebruik kan word. Gebaseer op die tesis dokumentasie beplan vooraanstaande raadgewende batebestuurders om die APM2 te integreer met hul batsbestuursprogram. Hierdie toepassing sal sodoende die APM2 in die praktyk toets en bekragtig. Dit word verder aanbeveel dat 'n batebestuursprogram, met die geassosieerde APM2, tesame met die Theory of Constraints en Total Productive Maintenance gebruik word, as gevolg van voor die hand liggende verwantskappe. Verdere navorsing word ook voorgestel in verband met die eksperimentele fases binne die batelewensiklus, asook rakende sekere finansiële oorwegings