Orientador: Alexandre César Rodrigues da Silva / Banca: Ernandes Rocha de Oliveira / Banca: Erica Regina Marani Daruichi Machado / Banca: Evandro de Araujo Jardini / Banca: João Henrique Kleinschmidt / Resumo: Neste trabalho é proposta uma arquitetura para publicação e universalização do acesso a transdutores inteligentes. Foram realizadas algumas pesquisas específicas sobre plataformas embarcadas com suporte à pilha de protocolos TCP/IP, arquiteturas orientadas a serviços e tecnologias para o desenvolvimento de aplicações clientes. As pesquisas realizadas contribuíram para a definição da proposta de arquitetura orientada a serviços baseada em transdutores inteligentes RESTful, gateways de tradução de padrões e serviços de retaguarda operando em computação em nuvem. Também são apresentadas algumas implementações e resultados obtidos com o desenvolvimento de alguns mecanismos e aplicações sobre a arquitetura. Esta arquitetura possibilita a operação de transdutores inteligentes em alto nível de abstração como serviços / Abstract: This work proposes an architecture for publication and universal access to smart transducers. Some specific research has been done on embedded platforms with support for the TCP/IP, service-oriented architectures and technologies for the development of client applications. The surveys have contributed to the definition of the proposed service-oriented architecture based on RESTful smart transducers, translation gateways of standards and back-office services operating on cloud computing. Also shown are some implementations and results obtained with the development of some mechanisms and applications over the architecture. This architecture enables the operation of smart transducers at a high level of abstraction as services / Doutor

This thesis describes the design and development of both the hardware and software of an embedded, distributed control system using a LAN infrastructure for communication between nodes. The primary application of this system is for power monitoring and control at Rhodes University. Both the hardware and software have been developed to provide a modular and scalable system capable of growing and adapting to meet the changing demands placed on it. The software includes a custom written Internet Protocol stack for use in the embedded environment, with a small code footprint and low processing overheads. There is also Linux-based control software, which includes a web-based device management interface and graphical output. Problems specific to the application are discussed as well as their solutions, with particular attention to the constraints of an embedded system.

M.Sc. (Computer Science) / Artificial intelligence strives towards providing an autonomous mechanism by which the environments of humans may be affected beneficially. The steps taken towards this goal have been to create individual computer programs that solve small problems; however, larger world problems need to be addressed. Intelligence in computer systems cannot be seen as a single algorithm which solves all problems, but rather a set of distinctive algorithms which may be combined uniquely in order to achieve a particular goal. One field of application for artificial intelligence in service to humanity is robotics. Autonomous robotic entities are becoming more commonplace in society, making their behaviour an important topic of study. Machines capable of performing various activities in service of the human race are fundamentally important if they are to be trusted to perform activities which could affect the health or well-being of their creators. The aim of the following research is to present the autonomous two-level agent framework (ATAF), a framework for intelligent agents to operate within a robotic entity. The entity must be able to adapt to various environments and situations and react in a manner consistent with its environment.

Trusted platform modules (TPMs) are hardware modules that are bound to a computer's motherboard, that are being included in many desktops and laptops. Augmenting computers with these hardware modules adds powerful functionality in distributed settings, allowing us to reason about the security of these systems in new ways. In this dissertation, I study the functionality of TPMs from a theoretical as well as an experimental perspective. On the theoretical front, I leverage various features of TPMs to construct applications like random oracles that are impossible to implement in a standard model of computation. Apart from random oracles, I construct a new cryptographic primitive which is basically a non-interactive form of the standard cryptographic primitive of oblivious transfer. I apply this new primitive to secure mobile agent computations, where interaction between various entities is typically required to ensure security. I prove these constructions are secure using standard cryptographic techniques and assumptions. To test the practicability of these constructions and their applications, I performed an experimental study, both on an actual TPM and a software TPM simulator which has been enhanced to make it reflect timings from a real TPM. This allowed me to benchmark the performance of the applications and test the feasibility of the proposed extensions to standard TPMs. My tests also show that these constructions are practical.

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Sensor networks including opportunistic networks of sensor-equipped smartphones as well as networks of embedded sensors can enable a wide range of applications including environmental monitoring, smart grids, intelligent transportation, and healthcare. In most real-world applications, to meet end-user requirements, the network operator needs to define and update the sensors' tasks dynamically, such as updating the parameters for sensor data collection or updating the sensors' code. Tasking sensor networks is necessary to reduce the effort in programming sensor networks. However, it is challenging due to dynamics and scale in terms of number of nodes, number of tasks, and sensing regions of the networks. In addition, tasking sensor networks must also be efficient in terms of bandwidth, latency, energy consumption, and memory usage. This dissertation identifies and addresses the problems of scalability and efficiency in tasking sensor networks. The first challenge in tasking sensor networks is to define a mechanism that represents multiple tasks and sensor groups efficiently taking into account the heterogeneity and mobility of sensors deployed over a large geographical region. Another challenge in tasking sensor networks in general, and embedded sensor networks in particular, is to design protocols that can not only efficiently disseminate tasks but also maintain a consistent view of the task to be performed among inherently unreliable and resource-limited sensors. We believe that a scalable and efficient tasking framework can greatly benefit the development and deployment of sensor network applications. Our thesis is that decoupling the task specification from task implementation using a spatial two-dimensional (2D) representation of a tasking region such as maps enables scalable, efficient, and resource-adaptive tasking over heterogeneous mobile sensor networks. In addition, reducing overhead in detecting inconsistencies across nodes enables scalable and efficient task dissemination and maintenance. We present the design, implementation, and evaluation of Zoom, a multiresolution tasking framework that efficiently encapsulates multiple tasks and sensor groups for sensor networks deployed in a large geographical region. The key ideas in Zoom are (i) decoupling task specification and task implementation to support heterogeneity, (ii) using maps for representing spatial sensor groups and tasks to scale with the number of sensor groups and sensing regions, and (iii) using image encoding techniques to reduce the map size and provide adaptation to sensor platforms with different resource capabilities. We present the design, implementation, and evaluation of our protocol, DHV, which efficiently disseminates task content and ensures that all nodes have up-to-date task content in sensor networks. It achieves this by minimizing both the redundant information in each message and the number of transmitted messages in the networks. DHV has been included in the official distribution of TinyOS, a popular operating system for embedded sensor networks. As sensor networks continue to develop, they will evolve from dedicated and single-purpose systems to open and multi-purpose large scale systems. Nodes in the network will be retasked frequently to support multiple applications and multiple users. We believe that this work is an important step in enabling seamless interaction between users and sensor networks and to make sensor networks more widely adopted.

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Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Embedded computer systems form part of larger systems such as aircraft or chemical processing facilities. Although testing and debugging of such systems are difficult, reliability is often essential. Development of embedded software can be simplified by an environment that limits opportunities for making errors and provides facilities for detection of errors. We implemented a language and compiler that can serve as basis for such an experimental environment. Both are designed to make verification of implementations feasible. Correctness and safety were given highest priority, but without sacrificing efficiency wherever possible. The language is concurrent and includes measures for protecting the address spaces of concurrently running processes. This eliminates the need for expensive run-time memory protection and will benefit resource-strapped embedded systems. The target hardware is assumed to provide no special support for concurrency. The language is designed to be small, simple and intuitive, and to promote compile-time detection of errors. Facilities for abstraction, such as modules and abstract data types support implementation and testing of bigger systems. We have opted for model checking as verification technique, so our implementation language is similar in design to a modelling language for a widely used model checker. Because of this, the implementation code can be used as input for a model checker. However, since the compiler can still contain errors, there might be discrepancies between the implementation code written in our language and the executable code produced by the compiler. Therefore we are attempting to make verification of executable code feasible. To achieve this, our compiler generates code in a special format, comprising a transition system of uninterruptible actions. The actions limit the scheduling points present in processes and reduce the different interleavings of process code possible in a concurrent system. Requirements that conventional hardware places on this form of code are discussed, as well as how the format influences efficiency and responsiveness. / AFRIKAANSE OPSOMMING: Ingebedde rekenaarstelsels maak deel uit van groter stelsels soos vliegtuie of chemiese prosesseerfasiliteite. Hoewel toetsing en ontfouting van sulke stelsels moeilik is, is betroubaarheid dikwels onontbeerlik. Ontwikkeling van ingebedde sagteware kan makliker gemaak word met 'n ontwikkelingsomgewing wat geleenthede vir foutmaak beperk en fasiliteite vir foutbespeuring verskaf. Ons het 'n programmeertaal en vertaler geïmplementeer wat as basis kan dien vir so 'n eksperimentele omgewing. Beide is ontwerp om verifikasie van implementasies haalbaar te maak. Korrektheid en veiligheid het die hoogste prioriteit geniet, maar sonder om effektiwiteit prys te gee, waar moontlik. Die taal is gelyklopend en bevat maatreëls om die adresruimtes van gelyklopende prosesse te beskerm. Dit maak duur looptyd-geheuebeskerming onnodig, tot voordeel van ingebedde stelsels met 'n tekort aan hulpbronne. Daar word aangeneem dat die teikenhardeware geen spesiale ondersteuning vir gelyklopendheid bevat nie. Die programmeertaal is ontwerp om klein, eenvoudig en intuïtief te wees, en om vertaaltyd-opsporing van foute te bevorder. Fasiliteite vir abstraksie, byvoorbeeld modules en abstrakte datatipes, ondersteun implementering en toetsing van groter stelsels. Ons het modeltoetsing as verifikasietegniek gekies, dus is die ontwerp van ons programmeertaal soortgelyk aan dié van 'n modelleertaal vir 'n modeltoetser wat algemeen gebruik word. As gevolg hiervan kan die implementasiekode as toevoer vir 'n modeltoetser gebruik word. Omdat die vertaler egter steeds foute kan bevat, mag daar teenstrydighede bestaan tussen die implementasie geskryf in ons implementasietaal, en die uitvoerbare masjienkode wat deur die vertaler gelewer word. Daarom poog ons om verifikasie van die uitvoerbare masjienkode haalbaar te maak. Om hierdie doelwit te bereik, is ons vertaler ontwerp om 'n spesiale formaat masjienkode te genereer bestaande uit 'n oorgangstelsel wat ononderbreekbare (atomiese) aksies bevat. Die aksies beperk die skeduleerpunte in prosesse en verminder sodoende die aantal interpaginasies van proseskode wat moontlik is in 'n gelyklopende stelsel. Die vereistes wat konvensionele hardeware aan dié spesifieke formaat kode stel, word bespreek, asook hoe die formaat effektiwiteit en reageerbaarheid van die stelsel beïnvloed.

Thesis (MSc) -- University of Stellenbosch, 2003. / ENGLISH ABSTRACT: A need for intelligent robotic machines is identified. Research and experiments have focussed on stable, or relatively stable, dynamic simulated systems to demonstrate the feasibility of embedding advanced AI into dynamic physical systems. This thesis presents an attempt to scale the techniques to a dynamically highly unstable system - the coordination of movements in a humanoid model. Environmental simulation, articulated systems and artificial intelligence methods are identified as three essential layers for a complete and unified approach to embedding AI into robotic machinery. The history of the physics subsystem for this project is discussed, leading to the adoption of the Open Dynamics Engine as the physics simulator of choice. An approach to articulated systems is presented along with the EBNF of a hierarchical articulated system that was used to describe the model. A revised form of evolution is presented and justified. An AI model that makes use of this new evolutionary paradigm is introduced. A variety of AI variants are defined and simulated. The results of these simulations are presented and analysed. Based on these results recommendations for future work are made. / AFRIKAANSE OPSOMMING: Die beheer van dinamiese masjiene, soos intelligente robotte, is tans beperk tot fisies stabilie - of relatief stabiele - sisteme. In hierdie tesis word die tegnieke van kunsmatige intelligensie (KI) toegepas op die kontrole en beheer van 'n dinamies hoogs onstabiele sisteem: 'n Humanoïede model. Fisiese simulasie, geartikuleerde sisteme en kunmatige intelligensie metodes word geïdentifiseer as drie noodsaaklike vereistes vir 'n volledige en eenvormige benadering tot KI beheer in robotte. Die implementasie van 'n fisiese simulator word beskryf, en 'n motivering vir die gebruik van die sogenaamde "Open Dynamics Engine" as fisiese simulator word gegee. 'n Benadering tot geartikuleerde sisteme word beskryf, tesame met die EBNF van 'n hierargiese geartikuleerde sisteem wat gebruik is om die model te beskryf. 'n Nuwe interpretasie vir evolusie word voorgestel, wat die basis vorm van 'n KI model wat in die tesis gebruik word. 'n Verskeidenheid van KI variasies word gedefineer en gesimuleer, en die resultate word beskryf en ontleed. Voorstelle vir verdere navorsing word gemaak.

Performance and power consumption are most important issues while designing embedded systems. Several studies have shown that cache memory consumes about 50% of the total power in these systems. Thus, the architecture of the cache governs both performance and power usage of embedded systems. A new N-way reconfigurable data cache is proposed especially for embedded systems. This thesis explores the issues and design considerations involved in designing a reconfigurable cache. The proposed reconfigurable data cache architecture can be configured as direct-mapped, two-way, or four-way set associative using a mode selector. The module has been designed and simulated in Xilinx ISE 9.1i and ModelSim SE 6.3e using the Verilog hardware description language.