Les machines multicœurs actuelles utilisent une architecture à Accès Mémoire Non-Uniforme (Non-Uniform Memory Access - NUMA). Dans ces machines, les cœurs sont regroupés en nœuds. Chaque nœud possède son propre contrôleur mémoire et est relié aux autres nœuds via des liens d'interconnexion. Utiliser ces architectures à leur pleine capacité est difficile : il faut notamment veiller à éviter les accès distants (i.e., les accès d'un nœud vers un autre nœud) et la congestion sur les bus mémoire et les liens d'interconnexion. L'optimisation de performance sur une machine NUMA peut se faire de deux manières : en implantant des optimisations ad-hoc au sein des applications ou de manière automatique en utilisant des heuristiques. Cependant, les outils existants fournissent trop peu d'informations pour pouvoir implanter efficacement des optimisations et les heuristiques existantes ne permettent pas d'éviter les problèmes de congestion. Cette thèse résout ces deux problèmes. Dans un premier temps nous présentons MemProf, le premier outil d'analyse permettant d'implanter efficacement des optimisations NUMA au sein d'applications. Pour ce faire, MemProf construit des flots d'interactions entre threads et objets. Nous évaluons MemProf sur 3 machines NUMA et montrons que les optimisations trouvées grâce à MemProf permettent d'obtenir des gains de performance significatifs (jusqu'à 2.6x) et sont très simples à implanter (moins de 10 lignes de code). Dans un second temps, nous présentons Carrefour, un algorithme de gestion de la mémoire pour machines NUMA. Contrairement aux heuristiques existantes, Carrefour se concentre sur la réduction de la congestion sur les machines NUMA. Carrefour permet d'obtenir des gains de performance significatifs (jusqu'à 3.3x) et est toujours plus performant que les heuristiques existantes. / Modern multicore systems are based on a Non-Uniform Memory Access (NUMA) design. In a NUMA system, cores are grouped in a set of nodes. Each node has a memory controller and is interconnected with other nodes using high speed interconnect links. Efficiently exploiting such architectures is notoriously complex for programmers. Two key objectives on NUMA multicore machines are to limit as much as possible the number of remote memory accesses (i.e., accesses from a node to another node) and to avoid contention on memory controllers and interconnect links. These objectives can be achieved by implementing application-level optimizations or by implementing application-agnostic heuristics. However, in many cases, existing profilers do not provide enough information to help programmers implement application-level optimizations and existing application-agnostic heuristics fail to address contention issues. The contributions of this thesis are twofold. First we present MemProf, a profiler that allows programmers to choose and implement efficient application-level optimizations for NUMA systems. MemProf builds temporal flows of interactions between threads and objects, which help programmers understand why and which memory objects are accessed remotely. We evaluate MemProf on Linux on three different machines. We show how MemProf helps us choose and implement efficient optimizations, unlike existing profilers. These optimizations provide significant performance gains (up to 2.6x), while requiring very lightweight modifications (10 lines of code or less). Then we present Carrefour, an application-agnostic memory management algorithm. Contrarily to existing heuristics, Carrefour focuses on traffic contention on memory controllers and interconnect links. Carrefour provides significant performance gains (up to 3.3x) and always performs better than existing heuristics.

Neste trabalho desenvolvemos um método de controle e aquisição de dados, particularmente aplicado a medidas de correntes termoestimuladas (TSC), mas que podem ser estendidas a sistemas semelhantes. O sistema automatizado de medidas TSC em plataforma GUI, foi implementado de modo a realizar o controle da temperatura de uma estufa, de forma que seja possível gerar rampas lineares com taxas programáveis, e também a leitura de sinais analógicos referentes ao sistema, como corrente e temperatura, e processar os sinais obtendo como resultado curvas gráficas (sinais processados em função do tempo). Os resultados são armazenados e podem ser exibidos, ou impressos e transferidos para o padrão de arquivo de entrada de outros aplicativos. Os dados são obtidos em tempo real e o sistema utiliza conceitos da tecnologia GUI, onde provemos um estudo desta, gerando janelas com interação orientada a eventos e uma interface gráfica com o usuário bastante interativa. O sistema faz uso de microcomputador padrão IBM PC AT e utiliza o MS-Windows 3.1 como plataforma GUI (\"GraphicsUser Interface\"). / A method for control and data acquisition using GUI environment, applied to thermal and electrical measurements was developed. The method was specifically applied to thermal stimulated current (TSC), but it can be extended to similar systems. The GUI - based automated TSC system maked possible the accurate control of the oven temperature, at different heating rates. This system performs the data acquisition of analogic signals (current and temperature, for instance), and those signals are processed generating functions of time and/or temperature (TSC curves, for example). Stored results can be displayed, printed, as well as transferred to files, which are compatible to standard applicative for data treatment. Data are obtained in real time and the system uses GUI concepts, which are extensively studied in this work, generating events oriented windows and a user-friendly graphical interface. The system configuration consists of an IBM PC AT microcomputer and the MS-Windows 3.1 is used as the GUI environment.

This dissertation studies the application of several event-driven control schemes in multi-agent systems. First, a new cooperative receding horizon (CRH) controller is designed and applied to a class of maximum reward collection problems. Target rewards are time-variant with finite deadlines and the environment contains uncertainties. The new methodology adapts an event-driven approach by optimizing the control for a planning horizon and updating it for a shorter action horizon. The proposed CRH controller addresses several issues including potential instabilities and oscillations. It also improves the estimated reward-to-go which enhances the overall performance of the controller. The other major contribution is that the originally infinite-dimensional feasible control set is reduced to a finite set at each time step which improves the computational cost of the controller. Second, a new event-driven methodology is studied for trajectory planning in multi-agent systems. A rigorous optimal control solution is employed using numerical solutions which turn out to be computationally infeasible in real time applications. The problem is then parameterized using several families of parametric trajectories. The solution to the parametric optimization relies on an unbiased estimate of the objective function's gradient obtained by the "Infinitesimal Perturbation Analysis" method. The premise of event-driven methods is that the events involved are observable so as to "excite" the underlying event-driven controller. However, it is not always obvious that these events actually take place under every feasible control in which case the controller may be useless. This issue of event excitation, which arises specially in multi-agent systems with a finite number of targets, is studied and addressed by introducing a novel performance measure which generates a potential field over the mission space. The effect of the new performance metric is demonstrated through simulation and analytical results.

This research examined the police-media relationship through an exploratory content analysis of news articles indexed as police brutality and/or deadly force published in six newspapers (The New York Times, Los Angeles Times, Chicago Tribune, St. Louis Post-Dispatch, Denver Post and USA Today) between August 9th, 2013 and August 9th, 2015. This timeframe was selected in order to determine whether significant differences exist between articles published in the year before the killing of Michael Brown in Ferguson, Missouri on August 9th, 2014 compared to those published in the year afterward. Specifically, this research examined whether and how news stories pre and post-Ferguson exhibited characteristics of Lawrence’s (2000) event-driven model of news production. Event-driven news stories are indicated by increased frequency of coverage and differences in the types of voices and views represented. Content analysis indicated significant increases in overall reporting on police brutality and deadly force were found in the year after the killing of Michael Brown compared to the year before. Also, there were increases in the types of voices and views associated with the event-driven model of news production (critical nonofficial voices and systematizing views) in the year after the killing of Brown compared to the year before. Finally, Critical Discourse Analysis (CDA) results indicated considerably different discourse construction in news stories indexed as police brutality or deadly force in the aftermath of Brown’s killing compared to similar articles published the year before. Specifically, racial categories are more emphasized and victims of police brutality and deadly force are constructed as more passive and sympathetic after Brown’s killing compared to the year before.

<p>Wireless Sensor nodes fall somewhere in between the single application devices that do</p><p>not need an operating system, and the more capable, general purpose devices with the</p><p>resources to run a traditional embedded operating system. Sensor node operating system</p><p>such as TinyOS, Contiki, MantisOS and SOS which is discussed in this paper exhibit</p><p>characteristics of both traditional embedded systems and general-purpose operating systems</p><p>providing a limited number of common services for application developers linking</p><p>software and hardware.</p><p>These common services typically include platform support, hardware management of sensors,</p><p>radios, and I/O buses and application construction etc. They also provide services</p><p>needed by applications which include task coordination, power management, adaptation</p><p>to resource constraints, and networking. The evaluation was concentrated on TinyOS</p><p>including an analysis on version 1.x and 2.x resource management and flexibility and its</p><p>operation with the other wireless sensor node operating systems.</p>

Wireless Sensor nodes fall somewhere in between the single application devices that do not need an operating system, and the more capable, general purpose devices with the resources to run a traditional embedded operating system. Sensor node operating system such as TinyOS, Contiki, MantisOS and SOS which is discussed in this paper exhibit characteristics of both traditional embedded systems and general-purpose operating systems providing a limited number of common services for application developers linking software and hardware. These common services typically include platform support, hardware management of sensors, radios, and I/O buses and application construction etc. They also provide services needed by applications which include task coordination, power management, adaptation to resource constraints, and networking. The evaluation was concentrated on TinyOS including an analysis on version 1.x and 2.x resource management and flexibility and its operation with the other wireless sensor node operating systems.

This document is a master’s thesis analyzing an automated fuel pump management system. In the first chapters we take a general overview of the system and the main problems that we will be facing during the planning and design phases of the project. Later we propose and analyze possible solutions for these problems. Technical system information is revealed in the later chapters. Functional and non functional requirements are discussed along with the main UML diagrams. The research phase of the thesis provides detailed system analysis and software quality reports which later are used to create proposed changes to the system. These changes are analyzed, designed and coded in the final - experimental part of the thesis. The main proposal is to convert the system architecture from flow driven to event driven. This change helps to solve several uncovered architectural problems as well as improve the general quality of the system. These changes are tested and analyzed in the experimental chapter of the thesis and finally the conclusions are made. The main conclusion is that the proposed architectural changes were chosen correctly. This is also supported by the experimental data.

This thesis focuses on measurement based software process improvement, especially improvement of requirements change management process. The literature on software measurement is investigated, software process improvement methodologies are studied and requirements change management metrics are examined. Requirements change management process at a private company working in the defense industry is observed and metrics obtained from various tools have been aggregated. Moreover, an improvement proposal, which also simplifies collecting metrics, is presented for the requirements change management process. A tool is developed for evaluating the performance of the improvement proposal using event driven simulation method.

Neste trabalho desenvolvemos um método de controle e aquisição de dados, particularmente aplicado a medidas de correntes termoestimuladas (TSC), mas que podem ser estendidas a sistemas semelhantes. O sistema automatizado de medidas TSC em plataforma GUI, foi implementado de modo a realizar o controle da temperatura de uma estufa, de forma que seja possível gerar rampas lineares com taxas programáveis, e também a leitura de sinais analógicos referentes ao sistema, como corrente e temperatura, e processar os sinais obtendo como resultado curvas gráficas (sinais processados em função do tempo). Os resultados são armazenados e podem ser exibidos, ou impressos e transferidos para o padrão de arquivo de entrada de outros aplicativos. Os dados são obtidos em tempo real e o sistema utiliza conceitos da tecnologia GUI, onde provemos um estudo desta, gerando janelas com interação orientada a eventos e uma interface gráfica com o usuário bastante interativa. O sistema faz uso de microcomputador padrão IBM PC AT e utiliza o MS-Windows 3.1 como plataforma GUI (\"GraphicsUser Interface\"). / A method for control and data acquisition using GUI environment, applied to thermal and electrical measurements was developed. The method was specifically applied to thermal stimulated current (TSC), but it can be extended to similar systems. The GUI - based automated TSC system maked possible the accurate control of the oven temperature, at different heating rates. This system performs the data acquisition of analogic signals (current and temperature, for instance), and those signals are processed generating functions of time and/or temperature (TSC curves, for example). Stored results can be displayed, printed, as well as transferred to files, which are compatible to standard applicative for data treatment. Data are obtained in real time and the system uses GUI concepts, which are extensively studied in this work, generating events oriented windows and a user-friendly graphical interface. The system configuration consists of an IBM PC AT microcomputer and the MS-Windows 3.1 is used as the GUI environment.

Existing database drivers use blocking socket I/O to exchange data with relational database management systems (RDBMS). To concurrently send multiple requests to a RDBMS with blocking database drivers, a separate thread must be used for each request. This approach has been used successfully for many years. However, we propose that using non-blocking socket I/O is faster and scales better under load. In this paper we introduce the Asynchronous Database Connectivity in Java (ADBCJ) framework. ADBCJ provides a common API for asynchronous RDBMS interaction. Various implementations of the ADBCJ API are used to show how utilizing non-blocking socket I/O is faster and scales better than using conventional database drivers and multiple threads for concurrency. Our experiments show a significant performance increase when using non- blocking socket I/O for asynchronous RDBMS access while using a minimal number of OS threads. Non-blocking socket I/O enables the ability to pipeline RDBMS requests which can improve performance significantly, especially over high latency networks. We also show the benefits of asynchronous database drivers on different web server architectures.