Dissertations / Theses: 'Autonomous distributed systems'

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Araguz, López Carles. "In pursuit of autonomous distributed satellite systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/668234.

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Satellite imagery has become an essential resource for environmental, humanitarian, and industrial endeavours. As a means to satisfy the requirements of new applications and user needs, novel Earth Observation (EO) systems are exploring the suitability of Distributed Satellite Systems (DSS) in which multiple observation assets concurrently sense the Earth. Given the temporal and spatial resolution requirements of EO products, DSS are often envisioned as large-scale systems with multiple sensing capabilities operating in a networked manner. Enabled by the consolidation of small satellite platforms and fostered by the emerging capabilities of distributed systems, these new architectures pose multiple design and operational challenges. Two of them are the main pillars of this research, namely, the conception of decision-support tools to assist the architecting process of a DSS, and the design of autonomous operational frameworks based on decentralised, on-board decision-making. The first part of this dissertation addresses the architecting of heterogeneous, networked DSS architectures that hybridise small satellite platforms with traditional EO assets. We present a generic design-oriented optimisation framework based on tradespace exploration methodologies. The goals of this framework are twofold: to select the most optimal constellation design; and to facilitate the identification of design trends, unfeasible regions, and tensions among architectural attributes. Oftentimes in EO DSS, system requirements and stakeholder preferences are not only articulated through functional attributes (i.e. resolution, revisit time, etc.) or monetary constraints, but also through qualitative traits such as flexibility, evolvability, robustness, or resiliency, amongst others. In line with that, the architecting framework defines a single figure of merit that aggregates quantitative attributes and qualitative ones-the so-called ilities of a system. With that, designers can steer the design of DSS both in terms of performance or cost, and in terms of their high-level characteristics. The application of this optimisation framework has been illustrated in two timely use-cases identified in the context of the EU-funded ONION project: a system that measures ocean and ice parameters in Polar regions to facilitate weather forecast and off-shore operations; and a system that provides agricultural variables crucial for global management of water stress, crop state, and draughts. The analysis of architectural features facilitated a comprehensive understanding of the functional and operational characteristics of DSS. With that, this thesis continues to delve into the design of DSS by focusing on one particular functional trait: autonomy. The minimisation of human-operator intervention has been traditionally sought in other space systems and can be especially critical for large-scale, structurally dynamic, heterogeneous DSS. In DSS, autonomy is expected to cope with the likely inability to operate very large-scale systems in a centralised manner, to improve the science return, and to leverage many of their emerging capabilities (e.g. tolerance to failures, adaptability to changing structures and user needs, responsiveness). We propose an autonomous operational framework that provides decentralised decision-making capabilities to DSS by means of local reasoning and individual resource allocation, and satellite-to-satellite interactions. In contrast to previous works, the autonomous decision-making framework is evaluated in this dissertation for generic constellation designs the goal of which is to minimise global revisit times. As part of the characterisation of our solution, we stressed the implications that autonomous operations can have upon satellite platforms with stringent resource constraints (e.g. power, memory, communications capabilities) and evaluated the behaviour of the solution for a large-scale DSS composed of 117 CubeSat-like satellite units.
La imatgeria per satèl·lit ha esdevingut un recurs essencial per assolir tasques ambientals, humanitàries o industrials. Per tal de satisfer els requeriments de les noves aplicacions i usuaris, els sistemes d’observació de la Terra (OT) estan explorant la idoneïtat dels Sistemes de Satèl·lit Distribuïts (SSD), on múltiples observatoris espacials mesuren el planeta simultàniament. Degut al les resolucions temporals i espacials requerides, els SSD sovint es conceben com sistemes de gran escala que operen en xarxa. Aquestes noves arquitectures promouen les capacitats emergents dels sistemes distribuïts i, tot i que són possibles gràcies a l’acceptació de les plataformes de satèl·lits petits, encara presenten molts reptes en quant al disseny i operacions. Dos d’ells són els pilars principals d’aquesta tesi, en concret, la concepció d’eines de suport a la presa de decisions pel disseny de SSD, i la definició d’operacions autònomes basades en gestió descentralitzada a bord dels satèl·lits. La primera part d’aquesta dissertació es centra en el disseny arquitectural de SSD heterogenis i en xarxa, imbricant tecnologies de petits satèl·lits amb actius tradicionals. Es presenta un entorn d’optimització orientat al disseny basat en metodologies d’exploració i comparació de solucions. Els objectius d’aquest entorn són: la selecció el disseny de constel·lació més òptim; i facilitar la identificació de tendències de disseny, regions d’incompatibilitat, i tensions entre atributs arquitecturals. Sovint en els SSD d’OT, els requeriments del sistema i l’expressió de prioritats no només s’articulen en quant als atributs funcionals o les restriccions monetàries, sinó també a través de les característiques qualitatives com la flexibilitat, l’evolucionabilitat, la robustesa, o la resiliència, entre d’altres. En línia amb això, l’entorn d’optimització defineix una única figura de mèrit que agrega rendiment, cost i atributs qualitatius. Així l’equip de disseny pot influir en les solucions del procés d’optimització tant en els aspectes quantitatius, com en les característiques dalt nivell. L’aplicació d’aquest entorn d’optimització s’il·lustra en dos casos d’ús actuals identificats en context del projecte europeu ONION: un sistema que mesura paràmetres de l’oceà i gel als pols per millorar la predicció meteorològica i les operacions marines; i un sistema que obté mesures agronòmiques vitals per la gestió global de l’aigua, l’estimació d’estat dels cultius, i la gestió de sequeres. L’anàlisi de propietats arquitecturals ha permès copsar de manera exhaustiva les característiques funcionals i operacionals d’aquests sistemes. Amb això, la tesi ha seguit aprofundint en el disseny de SSD centrant-se, particularment, en un tret funcional: l’autonomia. Minimitzar la intervenció de l’operador humà és comú en altres sistemes espacials i podria ser especialment crític pels SSD de gran escala, d’estructura dinàmica i heterogenis. En els SSD s’espera que l’autonomia solucioni la possible incapacitat d’operar sistemes de gran escala de forma centralitzada, que millori el retorn científic i que n’apuntali les seves propietats emergents (e.g. tolerància a errors, adaptabilitat a canvis estructural i de necessitats d’usuari, capacitat de resposta). Es proposa un sistema d’operacions autònomes que atorga la capacitat de gestionar els sistemes de forma descentralitzada, a través del raonament local, l’assignació individual de recursos, i les interaccions satèl·lit-a-satèl·lit. Al contrari que treballs anteriors, la presa de decisions autònoma s’avalua per constel·lacions que tenen com a objectius de missió la minimització del temps de revisita global.

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Miao, Xia Ph D. Massachusetts Institute of Technology. "Toward distributed control for autonomous electrical energy systems." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/128321.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2020
Cataloged from PDF of thesis.
Includes bibliographical references (pages 136-144).
In this thesis we study the problem of enabling autonomous electrical energy systems (AEESs) by means of distributed control. We first propose a modular modeling approach that represents a general electrical energy system (EES) as a negative feedback configuration comprising a planar electrical network subsystem and a subsystem of single-port components. The input-output specifications of all components are in terms of power and voltage. This mathematical modeling supports the basic physical functionality of balancing power supply and demand at the acceptable Quality of Service (QoS). These input-output specifications are met by the controllable components equipped with the newly proposed distributed control. We show that these controllers enable stable and feasible system-level closed-loop dynamics. Moreover, an interactive algorithm for autonomous adjustments of their controller set points based on the information exchange with neighboring components is introduced. This serves as a proof-of-concept illustration of how components adjust their power and voltage toward a system-level equilibrium. Such process is the basis for autonomous reconfigurable operation of small microgrids. As the first step toward scaling up the proposed concepts, we consider the problem of enhanced automatic generation control (E-AGC) for systems with highly dynamic load variations, including effects of intermittent renewable generation. Further work is needed to fully generalize this approach for control design of large-scale EES. In addition to theoretical results, we also report the results of several numerical and hardware tests. These show the effectiveness of the proposed approach in fairly complex scenarios, including unplanned large faults and hard-to-predict fast-varying power disturbances.
by Xia Miao.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

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Cliff, Oliver. "Information-theoretic Reasoning in Distributed and Autonomous Systems." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20512.

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The increasing prevalence of distributed and autonomous systems is transforming decision making in industries as diverse as agriculture, environmental monitoring, and healthcare. Despite significant efforts, challenges remain in robustly planning under uncertainty. In this thesis, we present a number of information-theoretic decision rules for improving the analysis and control of complex adaptive systems. We begin with the problem of quantifying the data storage (memory) and transfer (communication) within information processing systems. We develop an information-theoretic framework to study nonlinear interactions within cooperative and adversarial scenarios, solely from observations of each agent's dynamics. This framework is applied to simulations of robotic soccer games, where the measures reveal insights into team performance, including correlations of the information dynamics to the scoreline. We then study the communication between processes with latent nonlinear dynamics that are observed only through a filter. By using methods from differential topology, we show that the information-theoretic measures commonly used to infer communication in observed systems can also be used in certain partially observed systems. For robotic environmental monitoring, the quality of data depends on the placement of sensors. These locations can be improved by either better estimating the quality of future viewpoints or by a team of robots operating concurrently. By robustly handling the uncertainty of sensor model measurements, we are able to present the first end-to-end robotic system for autonomously tracking small dynamic animals, with a performance comparable to human trackers. We then solve the issue of coordinating multi-robot systems through distributed optimisation techniques. These allow us to develop non-myopic robot trajectories for these tasks and, importantly, show that these algorithms provide guarantees for convergence rates to the optimal payoff sequence.

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Athauda, Rukshan Indika. "Integration and querying of heterogeneous, autonomous, distributed database systems." FIU Digital Commons, 2000. http://digitalcommons.fiu.edu/etd/1332.

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Today, databases have become an integral part of information systems. In the past two decades, we have seen different database systems being developed independently and used in different applications domains. Today's interconnected networks and advanced applications, such as data warehousing, data mining & knowledge discovery and intelligent data access to information on the Web, have created a need for integrated access to such heterogeneous, autonomous, distributed database systems. Heterogeneous/multidatabase research has focused on this issue resulting in many different approaches. However, a single, generally accepted methodology in academia or industry has not emerged providing ubiquitous intelligent data access from heterogeneous, autonomous, distributed information sources. This thesis describes a heterogeneous database system being developed at Highperformance Database Research Center (HPDRC). A major impediment to ubiquitous deployment of multidatabase technology is the difficulty in resolving semantic heterogeneity. That is, identifying related information sources for integration and querying purposes. Our approach considers the semantics of the meta-data constructs in resolving this issue. The major contributions of the thesis work include: (i.) providing a scalable, easy-to-implement architecture for developing a heterogeneous multidatabase system, utilizing Semantic Binary Object-oriented Data Model (Sem-ODM) and Semantic SQL query language to capture the semantics of the data sources being integrated and to provide an easy-to-use query facility; (ii.) a methodology for semantic heterogeneity resolution by investigating into the extents of the meta-data constructs of component schemas. This methodology is shown to be correct, complete and unambiguous; (iii.) a semi-automated technique for identifying semantic relations, which is the basis of semantic knowledge for integration and querying, using shared ontologies for context-mediation; (iv.) resolutions for schematic conflicts and a language for defining global views from a set of component Sem-ODM schemas; (v.) design of a knowledge base for storing and manipulating meta-data and knowledge acquired during the integration process. This knowledge base acts as the interface between integration and query processing modules; (vi.) techniques for Semantic SQL query processing and optimization based on semantic knowledge in a heterogeneous database environment; and (vii.) a framework for intelligent computing and communication on the Internet applying the concepts of our work.

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Taylor, Philip Charles. "Distributed intelligent load control of autonomous renewable energy systems." Thesis, University of Manchester, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550559.

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A number of load control techniques and technologies have already been developed for autonomous power systems but no single technique has been widely adopted. Many of these load control systems have been partially successful but have suffered from a number of limitations that were addressed as part of this project. This thesis describes the development of distributed intelligent load controllers designed to address the limitations of previous load control solutions. A self-tuning fuzzy controller was developed to improve the power quality and efficiency of autonomous renewable energy systems. A laboratory wind-diesel test rig was developed to aid the design and testing of the load controller hardware and software. Computer models of wind powered and wind-diesel powered networks were produced to enable the design and testing of distributed fuzzy load control algorithms. The load controllers were tested throughout the development process on four autonomous renewable energy systems: - A single phase 25kVA run of river micro-hydro system in Scotland - A wind only system in the UK, with a 60kW stall regulated wind turbine fitted with a synchronous generator - A 30kW micro-hydro system on the island of Rum in Scotland - A 93kW wind-diesel system at the Rutherford Appleton Laboratories in the UK which used a 45kW stall regulated wind turbine fitted with an induction generator. The site results were promising and showed that distributed intelligent load control is an effective technique for controlling autonomous renewable energy systems.

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Santos, Vasco Pedro dos Anjos e. "DSAAR: distributed software architecture for autonomous robots." Master's thesis, FCT - UNL, 2009. http://hdl.handle.net/10362/1913.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica
This dissertation presents a software architecture called the Distributed Software Architecture for Autonomous Robots (DSAAR), which is designed to provide the fast development and prototyping of multi-robot systems. The DSAAR building blocks allow engineers to focus on the behavioural model of robots and collectives. This architecture is of special interest in domains where several human, robot, and software agents have to interact continuously. Thus, fast prototyping and reusability is a must. DSAAR tries to cope with these requirements towards an advanced solution to the n-humans and m-robots problem with a set of design good practices and development tools. This dissertation will also focus on Human-Robot Interaction, mainly on the subject of teleoperation. In teleoperation human judgement is an integral part of the process, heavily influenced by the telemetry data received from the remote environment. So the speed in which commands are given and the telemetry data is received, is of crucial importance. Using the DSAAR architecture a teleoperation approach is proposed. This approach was designed to provide all entities present in the network a shared reality, where every entity is an information source in an approach similar to the distributed blackboard. This solution was designed to accomplish a real time response, as well as, the completest perception of the robots’ surroundings. Experimental results obtained with the physical robot suggest that the system is able to guarantee a close interaction between users and robot.

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Ferdowsi, Khosrowshahi Aidin. "Distributed Machine Learning for Autonomous and Secure Cyber-physical Systems." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/99466.

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Autonomous cyber-physical systems (CPSs) such as autonomous connected vehicles (ACVs), unmanned aerial vehicles (UAVs), critical infrastructure (CI), and the Internet of Things (IoT) will be essential to the functioning of our modern economies and societies. Therefore, maintaining the autonomy of CPSs as well as their stability, robustness, and security (SRS) in face of exogenous and disruptive events is a critical challenge. In particular, it is crucial for CPSs to be able to not only operate optimally in the vicinity of a normal state but to also be robust and secure so as to withstand potential failures, malfunctions, and intentional attacks. However, to evaluate and improve the SRS of CPSs one must overcome many technical challenges such as the unpredictable behavior of a CPS's cyber-physical environment, the vulnerability to various disruptive events, and the interdependency between CPSs. The primary goal of this dissertation is, thus, to develop novel foundational analytical tools, that weave together notions from machine learning, game theory, and control theory, in order to study, analyze, and optimize SRS of autonomous CPSs. Towards achieving this overarching goal, this dissertation led to several major contributions. First, a comprehensive control and learning framework was proposed to thwart cyber and physical attacks on ACV networks. This framework brings together new ideas from optimal control and reinforcement learning (RL) to derive a new optimal safe controller for ACVs in order to maximize the street traffic flow while minimizing the risk of accidents. Simulation results show that the proposed optimal safe controller outperforms the current state of the art controllers by maximizing the robustness of ACVs to physical attacks. Furthermore, using techniques from convex optimization and deep RL a joint trajectory and scheduling policy is proposed in UAV-assisted networks that aims at maintaining the freshness of ground node data at the UAV. The analytical and simulation results show that the proposed policy can outperform policies such discretized state RL and value-based methods in terms of maximizing the freshness of data. Second, in the IoT domain, a novel watermarking algorithm, based on long short term memory cells, is proposed for dynamic authentication of IoT signals. The proposed watermarking algorithm is coupled with a game-theoretic framework so as to enable efficient authentication in massive IoT systems. Simulation results show that using our approach, IoT messages can be transmitted from IoT devices with an almost 100% reliability. Next, a brainstorming generative adversarial network (BGAN) framework is proposed. It is shown that this framework can learn to generate real-looking data in a distributed fashion while preserving the privacy of agents (e.g. IoT devices, ACVs, etc). The analytical and simulation results show that the proposed BGAN architecture allows heterogeneous neural network designs for agents, works without reliance on a central controller, and has a lower communication over head compared to other state-of-the-art distributed architectures. Last, but not least, the SRS challenges of interdependent CI (ICI) are addressed. Novel game-theoretic frameworks are proposed that allow the ICI administrator to assign different protection levels on ICI components to maximizing the expected ICI security. The mixed-strategy Nash of the games are derived analytically. Simulation results coupled with theoretical analysis show that, using the proposed games, the administrator can maximize the security level in ICI components. In summary, this dissertation provided major contributions across the areas of CPSs, machine learning, game theory, and control theory with the goal of ensuring SRS across various domains such as autonomous vehicle networks, IoT systems, and ICIs. The proposed approaches provide the necessary fundamentals that can lay the foundations of SRS in CPSs and pave the way toward the practical deployment of autonomous CPSs and applications.
Doctor of Philosophy
In order to deliver innovative technological services to their residents, smart cities will rely on autonomous cyber-physical systems (CPSs) such as cars, drones, sensors, power grids, and other networks of digital devices. Maintaining stability, robustness, and security (SRS) of those smart city CPSs is essential for the functioning of our modern economies and societies. SRS can be defined as the ability of a CPS, such as an autonomous vehicular system, to operate without disruption in its quality of service. In order to guarantee SRS of CPSs one must overcome many technical challenges such as CPSs' vulnerability to various disruptive events such as natural disasters or cyber attacks, limited resources, scale, and interdependency. Such challenges must be considered for CPSs in order to design vehicles that are controlled autonomously and whose motion is robust against unpredictable events in their trajectory, to implement stable Internet of digital devices that work with a minimum communication delay, or to secure critical infrastructure to provide services such as electricity, gas, and water systems. The primary goal of this dissertation is, thus, to develop novel foundational analytical tools, that weave together notions from machine learning, game theory, and control theory, in order to study, analyze, and optimize SRS of autonomous CPSs which eventually will improve the quality of service provided by smart cities. To this end, various frameworks and effective algorithms are proposed in order to enhance the SRS of CPSs and pave the way toward the practical deployment of autonomous CPSs and applications. The results show that the developed solutions can enable a CPS to operate efficiently while maintaining its SRS. As such, the outcomes of this research can be used as a building block for the large deployment of smart city technologies that can be of immense benefit to tomorrow's societies.

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Bordallo, Micó Alejandro. "Intention prediction for interactive navigation in distributed robotic systems." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28802.

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Modern applications of mobile robots require them to have the ability to safely and effectively navigate in human environments. New challenges arise when these robots must plan their motion in a human-aware fashion. Current methods addressing this problem have focused mainly on the activity forecasting aspect, aiming at improving predictions without considering the active nature of the interaction, i.e. the robot’s effect on the environment and consequent issues such as reciprocity. Furthermore, many methods rely on computationally expensive offline training of predictive models that may not be well suited to rapidly evolving dynamic environments. This thesis presents a novel approach for enabling autonomous robots to navigate socially in environments with humans. Following formulations of the inverse planning problem, agents reason about the intentions of other agents and make predictions about their future interactive motion. A technique is proposed to implement counterfactual reasoning over a parametrised set of light-weight reciprocal motion models, thus making it more tractable to maintain beliefs over the future trajectories of other agents towards plausible goals. The speed of inference and the effectiveness of the algorithms is demonstrated via physical robot experiments, where computationally constrained robots navigate amongst humans in a distributed multi-sensor setup, able to infer other agents’ intentions as fast as 100ms after the first observation. While intention inference is a key aspect of successful human-robot interaction, executing any task requires planning that takes into account the predicted goals and trajectories of other agents, e.g., pedestrians. It is well known that robots demonstrate unwanted behaviours, such as freezing or becoming sluggishly responsive, when placed in dynamic and cluttered environments, due to the way in which safety margins according to simple heuristics end up covering the entire feasible space of motion. The presented approach makes more refined predictions about future movement, which enables robots to find collision-free paths quickly and efficiently. This thesis describes a novel technique for generating "interactive costmaps", a representation of the planner’s costs and rewards across time and space, providing an autonomous robot with the information required to navigate socially given the estimate of other agents’ intentions. This multi-layered costmap deters the robot from obstructing while encouraging social navigation respectful of other agents’ activity. Results show that this approach minimises collisions and near-collisions, minimises travel times for agents, and importantly offers the same computational cost as the most common costmap alternatives for navigation. A key part of the practical deployment of such technologies is their ease of implementation and configuration. Since every use case and environment is different and distinct, the presented methods use online adaptation to learn parameters of the navigating agents during runtime. Furthermore, this thesis includes a novel technique for allocating tasks in distributed robotics systems, where a tool is provided to maximise the performance on any distributed setup by automatic parameter tuning. All of these methods are implemented in ROS and distributed as open-source. The ultimate aim is to provide an accessible and efficient framework that may be seamlessly deployed on modern robots, enabling widespread use of intention prediction for interactive navigation in distributed robotic systems.

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Richard, Mark G. "Cooperative control of distributed autonomous systems with applications to wireless sensor networks." Thesis, Monterey, Calif. : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Jun/09Jun%5FRichard.pdf.

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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2009.
Thesis Advisor(s): Lee, Deok Jin ; Kaminer, Issac I. "June 2009." Description based on title screen as viewed on 13 July 2009. Author(s) subject terms: Unmanned Aerial Vehicle, UAV, extremum seeking, simulink, high bandwidth communication links, SNR Model, coordinated control, cooperative control, decentralized control, wireless sensor network. Includes bibliographical references (p. 51). Also available in print.

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Hosseinimehr, Tahoura. "Power Management of Autonomous Microgrids with Distributed Generations and Energy Storage Systems." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59086.

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This thesis is mainly focused on the development of reliable power management strategics for islanded IVIGs. The main objectives of the proposed strategics are to provide accurate active and reactive power sharing, maintain system power balance, coordinate energy storage systems with distributed energy resources, enhance lifetime of the batteries by controlling their state of charge, and efficiently employ renewable energy sources such as photovoltaic (PV) systems in the lVIG, etc.

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Choi, Sungyun. "Autonomous state estimation and its application to the autonomous operation of the distribution system with distributed generations." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50250.

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The objective of this thesis is to propose guidelines for advanced operation, control, and protection of the restructured distribution system by designing the architecture and functionality for autonomous operation of the distribution system with DGs. The proposed architecture consists of (1) autonomous state estimation and (2) applications that enable autonomous operation; in particular, three applications are discussed: setting-less component protection, instant-by-instant management, and short-term operational planning. Key elements of the proposed approach have been verified: (1) the proposed autonomous state estimation has been experimentally tested using laboratory test systems and (2) the feasibility of the setting-less component protection has been tested with numerical simulations.

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Veelen, Martijn van. "Considerations on modeling for early detection of abnormalities in locally autonomous distributed systems." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/30031776X.

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Darr, Matthew John. "DEVELOPMENT AND EVALUATION OF A CONTROLLER AREA NETWORK BASED AUTONOMOUS VEHICLE." UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_theses/192.

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Through the work of researchers and the development of commercially availableproducts, automated guidance has become a viable option for agricultural producers.Some of the limitations of commercially available technologies are that they onlyautomate one function of the agricultural vehicle and that the systems are proprietary toa single machine model.The objective of this project was to evaluate a controller area network (CAN bus)as the basis of an automated guidance system. The prototype system utilized severalmicrocontroller-driven nodes to act as control points along a system wide CAN bus.Messages were transferred to the steering, transmission, and hitch control nodes from atask computer. The task computer utilized global positioning system data to determinethe appropriate control commands.Infield testing demonstrated that each of the control nodes could be controlledsimultaneously over the CAN bus. Results showed that the task computer adequatelyapplied a feedback control model to the system and achieved guidance accuracy levelswell within the range sought. Testing also demonstrated the system's ability tocomplete normal field operations such as headland turning and implement control.

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Ibidunmoye, Olumuyiwa. "Performance anomaly detection and resolution for autonomous clouds." Doctoral thesis, Umeå universitet, Institutionen för datavetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-142033.

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Fundamental properties of cloud computing such as resource sharing and on-demand self-servicing is driving a growing adoption of the cloud for hosting both legacy and new application services. A consequence of this growth is that the increasing scale and complexity of the underlying cloud infrastructure as well as the fluctuating service workloads is inducing performance incidents at a higher frequency than ever before with far-reaching impact on revenue, reliability, and reputation. Hence, effectively managing performance incidents with emphasis on timely detection, diagnosis and resolution has thus become a necessity rather than luxury. While other aspects of cloud management such as monitoring and resource management are experiencing greater automation, automated management of performance incidents remains a major concern. Given the volume of operational data produced by cloud datacenters and services, this thesis focus on how data analytics techniques can be used in the aspect of cloud performance management. In particular, this work investigates techniques and models for automated performance anomaly detection and prevention in cloud environments. To familiarize with developments in the research area, we present the outcome of an extensive survey of existing research contributions addressing various aspects of performance problem management in diverse systems domains. We discuss the design and evaluation of analytics models and algorithms for detecting performance anomalies in real-time behaviour of cloud datacenter resources and hosted services at different resolutions. We also discuss the design of a semi-supervised machine learning approach for mitigating performance degradation by actively driving quality of service from undesirable states to a desired target state via incremental capacity optimization. The research methods used in this thesis include experiments on real virtualized testbeds to evaluate aspects of proposed techniques while other aspects are evaluated using performance traces from real-world datacenters. Insights and outcomes from this thesis can be used by both cloud and service operators to enhance the automation of performance problem detection, diagnosis and resolution. They also have the potential to spur further research in the area while being applicable in related domains such as Internet of Things (IoT), industrial sensors as well as in edge and mobile clouds.
Grundläggande egenskaper för datormoln såsom resursdelning och självbetjäning driver ett växande nyttjande av molnet för internettjänster. En följd av denna tillväxt är att den underliggande molninfrastrukturens ökande storlek och komplexitet samt fluktuerade arbetsbelastning orsakar prestandaincidenter med högre frekvens än någonsin tidigare. En konsekvens av detta blir omfattande inverkan på intäkter, tillförlitlighet och rykte för de som äger tjänsterna. Det har därför blivit viktigt att snabbt och effektivt hantera prestandaincidenter med avseende på upptäckt, diagnos och korrigering. Även om andra aspekter av resurshantering för datormoln, som övervakning och resursallokering, på senare tid automatiserats i allt högre grad så är automatiserad hantering av prestandaincidenter fortfarande ett stort problem. Denna avhandling fokuserar på hur prestandahanteringen i molndatacenter kan förbättras genom användning av dataanalystekniker på de stora datamängder som produceras i de system som monitorerar prestanda hos datorresurser och tjänster. I synnerhet undersöks tekniker och modeller för automatisk upptäckt och förebyggande av prestandaanomalier i datormoln. För att kartlägga utvecklingen inom forskningsområdet presenterar vi resultatet av en omfattande undersökning av befintliga forskningsbidrag som behandlar olika aspekter av hantering av prestandaproblem inom i relevanta tillämpningsområden. Vi diskuterar design och utvärdering av analysmodeller och algoritmer för att upptäcka prestandaanomalier i realtid hos resurser och tjänster. Vi diskuterar också utformningen av ett maskininlärningsbaserat tillvägagångssätt för att mildra prestandaförluster genom att aktivt driva tjänsternas kvalitet från oönskade tillstånd till ett önskat målläge genom inkrementell kapacitetoptimering. Forskningsmetoderna som används i denna avhandling innefattar experiment på verkliga virtualiserade testmiljöer för att utvärdera aspekter av föreslagna tekniker medan andra aspekter utvärderas med hjälp av belastningsmönster från verkliga datacenter. Insikter och resultat från denna avhandling kan användas av både moln- och tjänsteoperatörer för att bättre automatisera detekteringen av prestandaproblem, inklusive dess diagnos och korrigering. Resultaten har också potential att uppmuntra vidare forskning inom området samtidigt som de är användbara inom relaterade områden som internet-av-saker, industriella sensorer, och storskaligt distribuerade moln eller telekomnätverk.
Cloud Control
eSSENCE

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15

Rogovchenko, Olena. "Abstractions for time and resource conscious composition in the context of distributed autonomous robotic systems." Paris 6, 2010. http://www.theses.fr/2010PA066659.

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Le domaine de la conception et de l'implantation de robots autonomesest aujourd'hui en pleine révolution. Forte croissance de la demande,large spectre d'applications, et l'explosion de la puissance de calculembarquée s'accompagnent d'une forte complexification de laprogrammation de leurs architectures de contrôle. Dans ce contexte,une approche à base de composants doit permettre de construire plusrapidement des architectures de contrôle complexes présentant desgaranties de bon fonctionnement. Dans ce domaine, cet objectif seheurte à de nombreuses difficultés. Les modèles à composantscourants, qui capturent pour l'essentiel un comportement fonctionneln'explicitant que les interactions de type appel/résultat, ne peuventrendre compte de l'ensemble des besoins pour construire unearchitecture de contrôle. Trop de caractéristiques vitales, liées auxpropriétés temporelles des tâches et à l'utilisation des ressourcesphysiques, demeurent implicites dans ces modèles. Le but de cette thèse est de développer un modèle formel d'interfaces riches permettant de représenter de manière systématique toutes les contraintes du système des contraintes fonctionnelles du composant aux contraintes physiques sur les ressources. Ces interfaces riches sont ensuite utilisées pour construire des assemblages de composants à travers un ensemble d'opérateurs de composition.

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16

Morais, de Lima C. H. (Carlos Héracles). "Opportunistic resource and network management in autonomous packet access systems." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526201771.

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Abstract This thesis aims to evaluate networking aspects of autonomous packets access systems when dynamically and adaptively performing resource and network management. In this context, Quality of Service (QoS)-aware solutions for resource sharing and control (e.g., channel access, load control, interference management and routing techniques among others) in large-scale wireless networks are envisaged. We propose and investigate distributed coordination mechanisms for controlling the co-channel interference generated in multi-tier coexistence scenarios consisting of macrocells underlaid with short-range small cells. The rationale behind employing such mechanism is to opportunistically reuse resources without compromising ongoing transmissions on the overlaid macrocells, while still guaranteeing QoS in both tiers. To mitigate the resulting co-channel interference, the underlaid tiers of small cells use distributed mechanism that relies on minimal signaling exchange, e.g., the Time Division Duplexing (TDD)-underlay approach which is based on regular busy tones. Herein, stochastic geometry is used to model network deployments, while higherorder statistics through the cumulants concept is utilized to characterize the probability distribution of the aggregate interference at the tagged receiver. To conduct our studies, we consider a shadowed fading channel model incorporating log-normal shadowing and Nakagami-m fading. In addition, various network algorithms, such as power control and frequency (re)allocation, are included in the analytical framework. To evaluate the performance of the proposed solutions, we also derive closed-form expressions for the outage probability and average spectral efficiency with respect to the receiver of interest under various channel conditions and network configurations. Results show that the analytical framework matches well with numerical results obtained from Monte Carlo simulations, and that the coordination mechanisms substantially improve the performance of overlaid macrocell networks, while also benefiting small cells. In contrast to the uncoordinated Frequency Division Duplexing mode, the coordinated TDD-underlay solution shows a reduction in the outage probability, while the average spectral efficiency increases at high loads. Although more elaborated interference control techniques such as, downlink bitmap and distributed antennas systems become needed, when the density of uncoordinated small cells in the underlaid tier gets high
Tiivistelmä Tämä väitöskirja pyrkii arvioimaan autonomisia pakettikytkentäisiä järjestelmiä verkon näkökulmasta, kun resurssien ja verkon hallinta tapahtuu dynaamisesti ja adaptiivisesti. Tässä yhteydessä suunnitellaan QoS-tietoisia ratkaisuja resurssien jakamiseen ja hallintaan (esim. kanavan allokointi, kuorman hallinta, häiriön käsittely ja reititystekniikat) suuren skaalan langattomiin verkkoihin. Ehdotamme ja tutkimme hajautettuja koordinointimekanismeja monikanavien häiriöiden hallintaan monitasoisissa skenaarioissa, jotka koostuvat lyhyen kantaman soluista makrosoluissa. Peruste näille mekanismeille on resurssien opportunistinen uudelleenkäyttö tinkimättä käynnissä olevista lähetyksistä suuremmissa makrosoluissa, samalla kun QoS taataan molemman tason lähetyksissä. Pienentääkseen aiheutuvaa monikanavahäiriöitä, alemman tason pienet solut käyttävät hajautettua mekanismia, kuten esimerkiksi säännöllisiin varattu-ääniin perustuvaa Time Division Duplexing (TDD) - mekanismia, vähällä signaalien vaihdon määrällä. Stokastista geometriaa käytetään mallintamaan verkkoja, kun taas korkeamman tason tilastollista laskentaa kumulanttimenetelmän käsitteen kautta käytetään kuvaamaan kokonaishäiriön todennäköisyysjakaumaa merkityssä vastaanottimessa. Käsittelemme varjostuvaa ja häipyvää kanavamallia sisältäen log-normaalin varjostumisen ja Nakagamim häipymisen. Lisäksi sisällytämme analyyttiseen työhön monenlaisia verkkoalgoritmeja tehohallintaan ja taajuuden (uudelleen)allokointiin. Ehdotettujen ratkaisujen tehokkuuden arvioimiseksi johdamme myös suljetut muodot katkosten todennäköisyyksille ja keskimääräiselle spektrin käytön tehokkuudelle halutun vastaanottimen suhteen monissa kanavatiloissa ja verkon kokoonpanoissa. Tulokset osoittavat, että analyyttisen työn tulokset vastaavat hyvin Monte Carlo - simulaatioilla saatujen numeeristen tulosten kanssa ja että koordinointimekanismit parantavat makrosoluverkkojen tehokkuutta merkittävästi, samalla kun myös pienet solut hyötyvät. Toisin kuin koordinoimaton Frequency Division Duplexing -toimintatila, koordinoitu TDD-toimintatila pienentää katkosten todennäköisyyttä samalla kun keskimääräinen spektrin käytön tehokkuus kasvaa suurella kuormalla. Toisaalta kehittyneemät häiriönhallintatekniikat, kuten alalinkki bittikartta sekä hajautetut antennijärjestelmät, tulevat tarpeelliseksi, kun pienten koordinoimattomattomien solujen tiheys kasvaa alemmalla tasolla

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17

Van, Horne Chris. "Machine Vision and Autonomous Integration Into an Unmanned Aircraft System." International Foundation for Telemetering, 2013. http://hdl.handle.net/10150/579707.

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ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV
The University of Arizona's Aerial Robotics Club (ARC) sponsors the development of an unmanned aerial vehicle (UAV) able to compete in the annual Association for Unmanned Vehicle Systems International (AUVSI) Seafarer Chapter Student Unmanned Aerial Systems competition. Modern programming frameworks are utilized to develop a robust distributed imagery and telemetry pipeline as a backend for a mission operator user interface. This paper discusses the design changes made for the 2013 AUVSI competition including integrating low-latency first-person view, updates to the distributed task backend, and incremental and asynchronous updates the operator's user interface for real-time data analysis.

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18

Bakolas, Efstathios. "Optimal steering for kinematic vehicles with applications to spatially distributed agents." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42873.

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The recent technological advances in the field of autonomous vehicles have resulted in a growing impetus for researchers to improve the current framework of mission planning and execution within both the military and civilian contexts. Many recent efforts towards this direction emphasize the importance of replacing the so-called monolithic paradigm, where a mission is planned, monitored, and controlled by a unique global decision maker, with a network centric paradigm, where the same mission related tasks are performed by networks of interacting decision makers (autonomous vehicles). The interest in applications involving teams of autonomous vehicles is expected to significantly grow in the near future as new paradigms for their use are constantly being proposed for a diverse spectrum of real world applications. One promising approach to extend available techniques for addressing problems involving a single autonomous vehicle to those involving teams of autonomous vehicles is to use the concept of Voronoi diagram as a means for reducing the complexity of the multi-vehicle problem. In particular, the Voronoi diagram provides a spatial partition of the environment the team of vehicles operate in, where each element of this partition is associated with a unique vehicle from the team. The partition induces, in turn, a graph abstraction of the operating space that is in a one-to-one correspondence with the network abstraction of the team of autonomous vehicles; a fact that can provide both conceptual and analytical advantages during mission planning and execution. In this dissertation, we propose the use of a new class of Voronoi-like partitioning schemes with respect to state-dependent proximity (pseudo-) metrics rather than the Euclidean distance or other generalized distance functions, which are typically used in the literature. An important nuance here is that, in contrast to the Euclidean distance, state-dependent metrics can succinctly capture system theoretic features of each vehicle from the team (e.g., vehicle kinematics), as well as the environment-vehicle interactions, which are induced, for example, by local winds/currents. We subsequently illustrate how the proposed concept of state-dependent Voronoi-like partition can induce local control schemes for problems involving networks of spatially distributed autonomous vehicles by examining different application scenarios.

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19

Pini, Giovanni. "Towards autonomous task partitioning in swarm robotics: experiments with foraging robots." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209469.

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In this thesis, we propose an approach to achieve autonomous task partitioning in swarms of robots. Task partitioning is the process by which tasks are decomposed into sub-tasks and it is often an advantageous way of organizing work in groups of individuals. Therefore, it is interesting to study its application to swarm robotics, in which groups of robots are deployed to collectively carry out a mission. The capability of partitioning tasks autonomously can enhance the flexibility of swarm robotics systems because the robots can adapt the way they decompose and perform their work depending on specific environmental conditions and goals. So far, few studies have been presented on the topic of task partitioning in the context of swarm robotics. Additionally, in all the existing studies, there is no separation between the task partitioning methods and the behavior of the robots and often task partitioning relies on characteristics of the environments in which the robots operate.

This limits the applicability of these methods to the specific contexts for which they have been built. The work presented in this thesis represents the first steps towards a general framework for autonomous task partitioning in swarms of robots. We study task partitioning in foraging, since foraging abstracts practical real-world problems. The approach we propose in this thesis is therefore studied in experiments in which the goal is to achieve autonomous task partitioning in foraging. However, in the proposed approach, the task partitioning process relies upon general, task-independent concepts and we are therefore confident that it is applicable in other contexts. We identify two main capabilities that the robots should have: i) being capable of selecting whether to employ task partitioning and ii) defining the sub-tasks of a given task. We propose and study algorithms that endow a swarm of robots with these capabilities.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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20

Dürr, Hans-Bernd. "Distributed Positioning of Autonomous Mobile Sensors with Application to the Coverage Problem : A Game Theoretic Approach to Multi-Agent Systems." Thesis, KTH, Reglerteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105128.

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In this thesis, general problems are considered where a group of agents should autonomously position themselves in such a way that a global objective function is maximized, whereas each agent uses only the measurement of its own utility function. Specially constructed extremum seeking schemes for single and multi-agent systems are presented, where the agents have only access to the current value of their individual utility functions and do not know the analytical model of the global or local objectives. By using an approximative system that is calculated using a methodology based on Lie brackets, practical stability of an equilibrium point is proved for the single agent as well as for the multi-agent case. The motion dynamics of the agents are modeled as single integrators, double integrators and unicycles. A potential game approach is used in order to deduce conditions under which the whole group of agents converges to a region arbitrary close to the maximum of a global objective function, that coincides with the Nash equilibrium of the game. As an application of the proposed algorithms, the sensor coverage problem is introduced. In this problem, a group of autonomous sensors is meant to position themselves such that a certain region is covered optimally, in the sense that the amount of detected events appearing in this region, is maximized. The problem is interpreted as a potential game where individual utility functions for each sensor are constructed in a way suitable for the direct application of the proposed optimization methodology.

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21

Malvaut-Martiarena, Willy. "Vers une architecture pair-à-pair pour l'informatique dans le nuage." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENM044/document.

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Avec l'émergence de l'informatique dans les nuages, une nouvelle approche consiste à externaliser des tâches de calcul, de façon à réduire les coûts d'hébergement et à augmenter la flexibilité des systèmes. L'infrastructure actuelle des services permettant cette externalisation repose sur l'utilisation de centres de traitement de données centralisés, qui sont dédiés à l'approvisionnement de ressources de calcul. Dans cette thèse, nous étudions la possibilité de fournir de tels services en utilisant une infrastructure pair-à-pair, c'est-à-dire une infrastructure totalement décentralisée pouvant être déployée sur une fédération de noeuds de calcul hétérogénes et de provenances diverses. Nous nous focalisons sur le problème de l'allocation des noeuds et présentons Salute, un service d'allocation de noeuds, qui organise les noeuds en réseaux virtuels non-structurés et repose sur des mécanismes de prédiction de disponibilité pour assurer, avec une grande probabilité, que les requêtes d'allocation sont satisfaites dans le temps, malgré le dynamisme de l'environnement hôte. Pour ce faire, le service Salute repose sur la collaboration de plusieurs protocoles pair-à-pair appartenant à la catégorie des protocoles épidémiques. Afin de valider nos propositions, nous évaluons Salute en utilisant des traces provenant d'un échantillonnage de plusieurs systèmes pair-à-pair de référence
With the emergence of Cloud computing, a new trend is to externalize computing tasks in order to decrease costs and increase flexibility. Current Cloud infrastructures rely on the usage of large-scale centralized data centers, for computing resources provisioning. In this thesis, we study the possibility to provide a peer-to-peer based Cloud infrastructure, which is totally decentralized and can be deployed on any computing nodes federation. We focus on the nodes allocation problem and present Salute, a nodes allocation service that organizes nodes in unstructured overlay networks and relies on mechanisms to predict node availability in order to ensure, with high probability, that allocation requests will be satisfied over time, and this despite churn. Salute's implementation relies on the collaboration of several peer-to-peer protocols belonging to the category of epidemic protocols. To convey our claims, we evaluate Salute using real traces

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22

Laine, Rickard. "To drone, or not to drone : A qualitative study in how and when information from UxV should be distributed in rescue missions at sea." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167054.

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Swedish maritime rescue consists of a number of resources from various organizations that will work together and achieve a common goal, to save people in need. It turns out that information is a significant factor in maritime rescue missions. Whether you are rescuer at the accident scene or coordinating the rescue mission from the control center, information provides you better situation awareness and knowledge of the situation, which creates better conditions in order achieve the goal for the mission. Applying Unmanned Vehicles (UxV) for Swedish maritime rescue means another resource that can provide additional necessary information. In this study, several methods have been used to find out where in the mission information from UxVs can conceivably contribute. The study identifies three critical situations where there is a need for UxV. This result, in turn, leads to other questions, such as who should be the recipient of the new information and how it affects the information flow as a whole? Information visualization proves to be an important factor in this. Where you can help the recipient of the information in their work with the help of clear and easily understood visualization without affecting the flow or coordination in their work.

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23

Santos, Frederico Miguel do Céu Marques dos. "Architecture for real-time coordination of multiple autonomous mobile units." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13969.

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Doutoramento em Engenharia Electrotécnica
Interest on using teams of mobile robots has been growing, due to their potential to cooperate for diverse purposes, such as rescue, de-mining, surveillance or even games such as robotic soccer. These applications require a real-time middleware and wireless communication protocol that can support an efficient and timely fusion of the perception data from different robots as well as the development of coordinated behaviours. Coordinating several autonomous robots towards achieving a common goal is currently a topic of high interest, which can be found in many application domains. Despite these different application domains, the technical problem of building an infrastructure to support the integration of the distributed perception and subsequent coordinated action is similar. This problem becomes tougher with stronger system dynamics, e.g., when the robots move faster or interact with fast objects, leading to tighter real-time constraints. This thesis work addressed computing architectures and wireless communication protocols to support efficient information sharing and coordination strategies taking into account the real-time nature of robot activities. The thesis makes two main claims. Firstly, we claim that despite the use of a wireless communication protocol that includes arbitration mechanisms, the self-organization of the team communications in a dynamic round that also accounts for variable team membership, effectively reduces collisions within the team, independently of its current composition, significantly improving the quality of the communications. We will validate this claim in terms of packet losses and communication latency. We show how such self-organization of the communications can be achieved in an efficient way with the Reconfigurable and Adaptive TDMA protocol. Secondly, we claim that the development of distributed perception, cooperation and coordinated action for teams of mobile robots can be simplified by using a shared memory middleware that replicates in each cooperating robot all necessary remote data, the Real-Time Database (RTDB) middleware. These remote data copies, which are updated in the background by the selforganizing communications protocol, are extended with age information automatically computed by the middleware and are locally accessible through fast primitives. We validate our claim showing a parsimonious use of the communication medium, improved timing information with respect to the shared data and the simplicity of use and effectiveness of the proposed middleware shown in several use cases, reinforced with a reasonable impact in the Middle Size League of RoboCup.
O interesse na utilização de equipas multi-robô tem vindo a crescer, devido ao seu potencial para cooperarem na resolução de vários problemas, tais como salvamento, desminagem, vigilância e até futebol robótico. Estas aplicações requerem uma infraestrutura de comunicação sem fios, em tempo real, suportando a fusão eficiente e atempada dos dados sensoriais de diferentes robôs bem como o desenvolvimento de comportamentos coordenados. A coordenação de vários robôs autónomos com vista a um dado objectivo é actualmente um tópico que suscita grande interesse, e que pode ser encontrado em muitos domínios de aplicação. Apesar das diferenças entre domínios de aplicação, o problema técnico de construir uma infraestrutura para suportar a integração da percepção distribuída e das acções coordenadas é similar. O problema torna-se mais difícil à medida que o dinamismo dos robôs se acentua, por exemplo, no caso de se moverem mais rápido, ou de interagirem com objectos que se movimentam rapidamente, dando origem a restrições de tempo-real mais apertadas. Este trabalho centrou-se no desenvolvimento de arquitecturas computacionais e protocolos de comunicação sem fios para suporte à partilha de informação e à realização de acções coordenadas, levando em consideração as restrições de tempo-real. A tese apresenta duas afirmações principais. Em primeiro lugar, apesar do uso de um protocolo de comunicação sem fios que inclui mecanismos de arbitragem, a auto-organização das comunicações reduz as colisões na equipa, independentemente da sua composição em cada momento. Esta afirmação é validada em termos de perda de pacotes e latência da comunicação. Mostra-se também como a auto-organização das comunicações pode ser atingida através da utilização de um protocolo TDMA reconfigurável e adaptável sem sincronização de relógio. A segunda afirmação propõe a utilização de um sistema de memória partilhada, com replicação nos diferentes robôs, para suportar o desenvolvimento de mecanismos de percepção distribuída, fusão sensorial, cooperação e coordenação numa equipa de robôs. O sistema concreto que foi desenvolvido é designado como Base de Dados de Tempo Real (RTDB). Os dados remotos, que são actualizados de forma transparente pelo sistema de comunicações auto-organizado, são estendidos com a respectiva idade e são disponibilizados localmente a cada robô através de primitivas de acesso eficientes. A RTDB facilita a utilização parcimoniosa da rede e bem como a manutenção de informação temporal rigorosa. A simplicidade da integração da RTDB para diferentes aplicações permitiu a sua efectiva utilização em diferentes projectos, nomeadamente no âmbito do RoboCup.

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24

Landén, David. "Complex Task Allocation for Delegation : From Theory to Practice." Licentiate thesis, Linköpings universitet, KPLAB - Laboratoriet för kunskapsbearbetning, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70536.

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The problem of determining who should do what given a set of tasks and a set of agents is called the task allocation problem. The problem occurs in many multi-agent system applications where a workload of tasks should be shared by a number of agents. In our case, the task allocation problem occurs as an integral part of a larger problem of determining if a task can be delegated from one agent to another. Delegation is the act of handing over the responsibility for something to someone. Previously, a theory for delegation including a delegation speech act has been specified. The speech act specifies the preconditions that must be fulfilled before the delegation can be carried out, and the postconditions that will be true afterward. To actually use the speech act in a multi-agent system, there must be a practical way of determining if the preconditions are true. This can be done by a process that includes solving a complex task allocation problem by the agents involved in the delegation. In this thesis a constraint-based task specification formalism, a complex task allocation algorithm for allocating tasks to unmanned aerial vehicles and a generic collaborative system shell for robotic systems are developed. The three components are used as the basis for a collaborative unmanned aircraft system that uses delegation for distributing and coordinating the agents' execution of complex tasks.

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25

Davis, Cledo L. "The systems integration of autonomous behavior analysis to create a "Maritime Smart Environment" for the enhancement of maritime domain awareness." Thesis, Monterey, California : Naval Postgraduate School, 2010. http://edocs.nps.edu/npspubs/scholarly/theses/2010/Jun/10Jun%5FDavis.pdf.

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Thesis (M.S. in Systems Engineering)--Naval Postgraduate School, June 2010.
Thesis Advisor(s): Goshorn, Rachel ; Goshorn, Deborah. "June 2010." Description based on title screen as viewed on June 24, 2010. Author(s) subject terms: Anomaly Detection, Artificial Intelligence, Automation, Behavior Analysis, Distributed Artificial Intelligence, Intelligence-Surveillance-Reconnaissance, Maritime Domain Awareness, Maritime Force Protection, Multi-agent Systems, Network-centric Operations, Network-centric Systems Engineering, Network-centric Warfare, Smart Sensor Networks, Systems Engineering, Systems Integration, System of Systems. Includes bibliographical references (p. 209-212). Also available in print.

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26

Quesnel, Flavien. "Vers une gestion coopérative des infrastructures virtualisées à large échelle : le cas de l'ordonnancement." Phd thesis, Ecole des Mines de Nantes, 2013. http://tel.archives-ouvertes.fr/tel-00821103.

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Les besoins croissants en puissance de calcul sont généralement satisfaits en fédérant de plus en plus d'ordinateurs (ou noeuds) pour former des infrastructures distribuées. La tendance actuelle est d'utiliser la virtualisation système dans ces infrastructures, afin de découpler les logiciels des noeuds sous-jacents en les encapsulant dans des machines virtuelles. Pour gérer efficacement ces infrastructures virtualisées, de nouveaux gestionnaires logiciels ont été mis en place. Ces gestionnaires sont pour la plupart hautement centralisés (les tâches de gestion sont effectuées par un nombre restreint de nœuds dédiés). Cela limite leur capacité à passer à l'échelle, autrement dit à gérer de manière réactive des infrastructures de grande taille, qui sont de plus en plus courantes. Au cours de cette thèse, nous nous sommes intéressés aux façons d'améliorer cet aspect ; l'une d'entre elles consiste à décentraliser le traitement des tâches de gestion, lorsque cela s'avère judicieux. Notre réflexion s'est concentrée plus particulièrement sur l'ordonnancement dynamique des machines virtuelles, pour donner naissance à la proposition DVMS (Distributed Virtual Machine Scheduler). Nous avons mis en œuvre un prototype, que nous avons validé au travers de simulations (notamment via l'outil SimGrid), et d'expériences sur le banc de test Grid'5000. Nous avons pu constater que DVMS se montrait particulièrement réactif pour gérer des infrastructures virtualisées constituées de dizaines de milliers de machines virtuelles réparties sur des milliers de nœuds. Nous nous sommes ensuite penchés sur les perspectives d'extension et d'amélioration de DVMS. L'objectif est de disposer à terme d'un gestionnaire décentralisé complet, objectif qui devrait être atteint au travers de l'initiative Discovery qui fait suite à ces travaux.

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Giansiracusa, Michelangelo Antonio. "A secure infrastructural strategy for safe autonomous mobile agents." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16052/1/Michaelangelo_Giansiracusa_Thesis.pdf.

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Portable languages and distributed paradigms have driven a wave of new applications and processing models. One of the most promising, certainly from its early marketing, but disappointing (from its limited uptake)is the mobile agent execution and data processing model. Mobile agents are autonomous programs which can move around a heterogeneous network such as the Internet, crossing through a number of different security domains, and perform some work at each visited destination as partial completion of a mission for their agent user. Despite their promise as a technology and paradigm to drive global electronic services (i.e.any Internet-driven-and-delivered service, not solely e-commerce related activities), their up take on the Internet has been very limited. Chief among the reasons for the paradigm's practical under-achievement is there is no ubiquitous frame work for using Internet mobile agents, and non-trivial security concerns abound for the two major stake holders (mobile agent users and mobile agent platform owners). While both stake holders have security concerns with the dangers of the mobile agent processing model, most investigators in the field are of the opinion that protecting mobile agents from malicious agent platforms is more problematic than protecting agent platforms from malicious mobile agents. Traditional cryptographic mechanisms are not well-suited to counter the bulk of the threats associated with the mobile agent paradigm due to the untrusted hosting of an agent and its intended autonomous, flexible movement and processing. In our investigation, we identified that the large majority of the research undertaken on mobile agent security to date has taken a micro-level perspective. By this we mean research focused solely on either of the two major stakeholders, and even then often only on improving measures to address one security issue dear to the stake holder - for example mobile agent privacy (for agent users) or access control to platform resources (for mobile agent platform owners). We decided to take a more encompassing, higher-level approach in tackling mobile agent security issues. In this endeavour, we developed the beginnings of an infrastructural-approach to not only reduce the security concerns of both major stakeholders, but bring them transparently to a working relationship. Strategic utilisation of both existing distributed system trusted-third parties (TTPs) and novel mobile agent paradigm-specific TTPs are fundamental in the infrastructural framework we have devised. Besides designing an application and language independent frame work for supporting a large-scale Internet mobile agent network, our Mobile Agent Secure Hub Infrastructure (MASHIn) proposal encompasses support for flexible access control to agent platform resources. A reliable means to track the location and processing times of autonomous Internet mobile agents is discussed, withfault-tolerant handling support to work around unexpected processing delays. Secure,highly-effective (incomparison to existing mechanisms) strategies for providing mobile agent privacy, execution integrity, and stake holder confidence scores were devised - all which fit comfortably within the MASHIn framework. We have deliberately considered the interests - withoutbias -of both stake holders when designing our solutions. In relation to mobile agent execution integrity, we devised a new criteria for assessing the robustness of existing execution integrity schemes. Whilst none of the existing schemes analysed met a large number of our desired properties for a robust scheme, we identified that the objectives of Hohl's reference states scheme were most admirable - particularly real - time in - mission execution integrity checking. Subsequently, we revised Hohl's reference states protocols to fit in the MASHIn framework, and were able to overcome not only the two major limitations identified in his scheme, but also meet all of our desired properties for a robust execution integrity scheme (given an acceptable decrease in processing effiency). The MASHIn offers a promising new perspective for future mobile agent security research and indeed a new frame work for enabling safe and autonomous Internet mobile agents. Just as an economy cannot thrive without diligent care given to micro and macro-level issues, we do not see the security prospects of mobile agents (and ultimately the prospects of the mobile agent paradigm) advancing without diligent research on both levels.

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28

Giansiracusa, Michelangelo Antonio. "A Secure Infrastructural Strategy for Safe Autonomous Mobile Agents." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16052/.

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Portable languages and distributed paradigms have driven a wave of new applications and processing models. One of the most promising, certainly from its early marketing, but disappointing (from its limited uptake)is the mobile agent execution and data processing model. Mobile agents are autonomous programs which can move around a heterogeneous network such as the Internet, crossing through a number of different security domains, and perform some work at each visited destination as partial completion of a mission for their agent user. Despite their promise as a technology and paradigm to drive global electronic services (i.e.any Internet-driven-and-delivered service, not solely e-commerce related activities), their up take on the Internet has been very limited. Chief among the reasons for the paradigm's practical under-achievement is there is no ubiquitous frame work for using Internet mobile agents, and non-trivial security concerns abound for the two major stake holders (mobile agent users and mobile agent platform owners). While both stake holders have security concerns with the dangers of the mobile agent processing model, most investigators in the field are of the opinion that protecting mobile agents from malicious agent platforms is more problematic than protecting agent platforms from malicious mobile agents. Traditional cryptographic mechanisms are not well-suited to counter the bulk of the threats associated with the mobile agent paradigm due to the untrusted hosting of an agent and its intended autonomous, flexible movement and processing. In our investigation, we identified that the large majority of the research undertaken on mobile agent security to date has taken a micro-level perspective. By this we mean research focused solely on either of the two major stakeholders, and even then often only on improving measures to address one security issue dear to the stake holder - for example mobile agent privacy (for agent users) or access control to platform resources (for mobile agent platform owners). We decided to take a more encompassing, higher-level approach in tackling mobile agent security issues. In this endeavour, we developed the beginnings of an infrastructural-approach to not only reduce the security concerns of both major stakeholders, but bring them transparently to a working relationship. Strategic utilisation of both existing distributed system trusted-third parties (TTPs) and novel mobile agent paradigm-specific TTPs are fundamental in the infrastructural framework we have devised. Besides designing an application and language independent frame work for supporting a large-scale Internet mobile agent network, our Mobile Agent Secure Hub Infrastructure (MASHIn) proposal encompasses support for flexible access control to agent platform resources. A reliable means to track the location and processing times of autonomous Internet mobile agents is discussed, withfault-tolerant handling support to work around unexpected processing delays. Secure,highly-effective (incomparison to existing mechanisms) strategies for providing mobile agent privacy, execution integrity, and stake holder confidence scores were devised - all which fit comfortably within the MASHIn framework. We have deliberately considered the interests - withoutbias -of both stake holders when designing our solutions. In relation to mobile agent execution integrity, we devised a new criteria for assessing the robustness of existing execution integrity schemes. Whilst none of the existing schemes analysed met a large number of our desired properties for a robust scheme, we identified that the objectives of Hohl's reference states scheme were most admirable - particularly real - time in - mission execution integrity checking. Subsequently, we revised Hohl's reference states protocols to fit in the MASHIn framework, and were able to overcome not only the two major limitations identified in his scheme, but also meet all of our desired properties for a robust execution integrity scheme (given an acceptable decrease in processing effiency). The MASHIn offers a promising new perspective for future mobile agent security research and indeed a new frame work for enabling safe and autonomous Internet mobile agents. Just as an economy cannot thrive without diligent care given to micro and macro-level issues, we do not see the security prospects of mobile agents (and ultimately the prospects of the mobile agent paradigm) advancing without diligent research on both levels.

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29

Rollerberg, Niklas. "A distributed navigation and guidance system for autonomous vessel." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-255011.

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Using distributed micro-controllers in an autonomous vessel can result in higher robustness and lower energy consumption compared to a traditional centralized approach. However adapting traditional software (e.g. navigation and guidance systems) for a distributed microcontroller system is a complex and challenging task. In this thesis a software solution for controlling autonomous vessels with on board distributed micro-controllers is presented. It is capable of controlling the vehicle by itself, including routing around obstacles in moderately complex environments, or act as an interface to another computer. The routing capabilities come from the use of a high-level path-planner based on RRT, and a low-level vehicle controller based on potential fields to follow the path from the path-planner. By using these methods together the software is capable maneuvering a sailboat between waypoints. In our experiments distributed computing is investigated for the path planning and evaluated in terms of computational time for 1,2 and 3 nodes. A parallelization technique called OR parallelization was tested and it offered a reduction in computational time by 27% with two nodes and 36% for three nodes against a single node. Nevertheless, this gain may not be, significant enough to warrant the extra complexity.
Att använda distribuerade mikro-controllers i en autonom farkost kan resultera i ett robustare och energisnålare system jämfört med ett traditionellt centraliserat system, dock så är det en utmanande och komplex uppgift att anpassa existerande mjukvara för navigation och styrning till ett sådant system. I denna rapport presenteras en mjukvarulösning för styrning av autonoma farkoster med ett distribuerat system av mikro-controllers som finns ombord. Mjukvaran kan antingen kontrollera farkosten själv (inklusive rutt-planering runt hinder i måttligt komplexa miljöer), eller fungera som gränssnitt till ett annat system. Rutt-planeringen görs av en planeringsalgoritm som heter RRT tillsammans en lågnivåkontroller som använder sig av potentialfält för att följa rutten från planeraren. Med dessa två steg så kan mjukvaran styra en segelbåt mellan givna platser. Distribuerade beräkningar undersöks för ruttplaneringen och utvärderas i termer av beräkningstid för 1,2 och 3 noder. En parallelliseringsteknik som heter OR-parallellisering testades och gav prestandavinster på 27% respektive 36% för 2 och 3 noder. Författaren tycker dock inte att den prestandavinsten är hög nog för att väga upp den extra komplexitet som den medför.

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30

Holt, Ryan S. "Three Enabling Technologies for Vision-Based, Forest-Fire Perimeter Surveillance Using Multiple Unmanned Aerial Systems." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/931.

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The ability to gather and process information regarding the condition of forest fires is essential to cost-effective, safe, and efficient fire fighting. Advances in sensory and autopilot technology have made miniature unmanned aerial systems (UASs) an important tool in the acquisition of information. This thesis addresses some of the challenges faced when employing UASs for forest-fire perimeter surveillance; namely, perimeter tracking, cooperative perimeter surveillance, and path planning. Solutions to the first two issues are presented and a method for understanding path planning within the context of a forest-fire environment is demonstrated. Both simulation and hardware results are provided for each solution.

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31

Dai, Hanping. "Distributed control system architecture and smart sensing for intelligent semi-autonomous vehicles." Thesis, De Montfort University, 2002. http://hdl.handle.net/2086/4784.

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32

Dinkel, Michael. "A novel IT-architecture for self-management in distributed embedded systems." Duisburg Köln WiKu-Verl, 2007. http://d-nb.info/987718878/04.

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33

Louail, Malik. "Intégration de la qualité de service (QoS) dans l’internet industriel des objets (IIoT) pour l’usine du futur." Electronic Thesis or Diss., Troyes, 2022. http://www.theses.fr/2022TROY0010.

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Avec l'intégration d'Internet dans la production industrielle, le concept d'Internet industriel des objets (IIoT) est devenu l'un des outils les plus innovants pour les usines. L'IIoT permet aux opérations industrielles intelligentes de gérer de grande quantité de tâches provenant des usines intelligentes. Ces tâches entrantes doivent être exécutées dans un nœud fog ou dans le cloud, en respectant un ensemble de contraintes. Dans cette thèse, après avoir introduit une classification de la littérature qui existe dans ce domaine, nous introduisons un ordonnanceur de réseau dynamique pour le réseau fog afin de gérer les tâches industrielles dans le but d'obtenir une bonne gestion à travers le réseau. Dans une deuxième étape, nous améliorons notre système à travers un protocole de routage optimisé qui considère une méthode d'intelligence artificielle pour que le système s'adapte aux changements et reste sur une bonne prise de décisions. Sous certaines conditions, nos résultats des simulations sont meilleurs par rapport aux algorithmes d'ordonnancement existants dans des travaux antérieurs. Globalement, la mesure de certaines métriques de qualité de service dans le réseau fog, en temps réel, avec la mise en place d'algorithmes d'ordonnancement adéquat, améliore les performances, la productivité et bénéfices de l'usine intelligente
With the integration of Internet in industrial production and in manufacturing, the concept of Industrial Internet of things (IIoT) has become one of the most innovative tools for factories. IIoT enables intelligent industrial operations to deal with the big amount of tasks coming from the smart factories. These incoming tasks have to be executed in a fog node or in the cloud, respecting a set of constraints. In this thesis, we introduce a classification of the litterature dealing with task scheduling in fog computing. We present a dynamic network scheduler for the fogs network in order to handle smart manufacturing tasks in the aim to achieve a good management through the network. We also propose an enhacement of our system by making an optimzed routing protocol based on artificial intelligence method which makes the system better at decision making and more adaptable to changes. Extensive simulations have shown that the proposed systems have better performance, in terms of rejected tasks, than similar existing works under certain conditions. Globally, the measure of some quality of service metrics in the fog network, in real time, and with implementing adaptable task scheduling algorithms improve the performance, the productivity and the benefits of the smart factory

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Mhereeg, Mohammed Ramadan. "Development of an autonomous distributed multiagent monitoring system for the automatic classification of end users." Thesis, University of South Wales, 2011. https://pure.southwales.ac.uk/en/studentthesis/development-of-an-autonomous-distributed-multiagent-monitoring-system-for-the-automatic-classification-of-end-users(bacbef24-a18c-4a4e-afbb-2fbae6863047).html.

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The purpose of this study is to investigate the feasibility of constructing a software Multi-Agent based monitoring and classification system and utilizing it to provide an automated and accurate classification for end users developing applications in the spreadsheet domain. Resulting in, is the creation of the Multi-Agent Classification System (MACS). The Microsoft‘s .NET Windows Service based agents were utilized to develop the Monitoring Agents of MACS. These agents function autonomously to provide continuous and periodic monitoring of spreadsheet workbooks by content. .NET Windows Communication Foundation (WCF) Services technology was used together with the Service Oriented Architecture (SOA) approach for the distribution of the agents over the World Wide Web in order to satisfy the monitoring and classification of the multiple developer aspect. The Prometheus agent oriented design methodology and its accompanying Prometheus Design Tool (PDT) was employed for specifying and designing the agents of MACS, and Visual Studio.NET 2008 for creating the agency using visual C# programming language. MACS was evaluated against classification criteria from the literature with the support of using real-time data collected from a target group of excel spreadsheet developers over a network. The Monitoring Agents were configured to execute automatically, without any user intervention as windows service processes in the .NET web server application of the system. These distributed agents listen to and read the contents of excel spreadsheets development activities in terms of file and author properties, function and formulas used, and Visual Basic for Application (VBA) macro code constructs. Data gathered by the Monitoring Agents from various resources over a period of time was collected and filtered by a Database Updater Agent residing in the .NET client application of the system. This agent then transfers and stores the data in Oracle server database via Oracle stored procedures for further processing that leads to the classification of the end user developers. Oracle data mining classification algorithms: Naive Bayes, Adaptive Naive Bayes, Decision Trees, and Support Vector Machine were utilized to analyse the results from the data gathering process in order to automate the classification of excel spreadsheet developers. The accuracy of the predictions achieved by the models was compared. The results of the comparison showed that Naive Bayes classifier achieved the best results with accuracy of 0.978. Therefore, the MACS can be utilized to provide a Multi-Agent based automated classification solution to spreadsheet developers with a high degree of accuracy.

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35

Tlig, Mohamed. "Coordination locale et optimisation distribuée du trafic de véhicules autonomes dans un réseau routier." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0049/document.

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Dans le cadre de cette thèse, nous nous intéressons à la coordination et l'optimisation du trafic aux intersections des réseaux routiers, avec la particularité de considérer des véhicules autonomes intelligents. Cette thèse est organisée en deux grandes parties. La première se concentre sur le problème du partage d'un espace de voie par deux files de véhicules évoluant en sens opposés. L'état de l'art montre le peu de travaux abordant cette question. Nous explorons deux approches par coordination réactive, en relation avec un critère de minimisation des retards. Les performances de ces approches ont été mesurées statistiquement en simulation. La deuxième partie de la thèse s'attaque au problème générique de la gestion du trafic au sein d'un réseau routier. Nous développons une approche originale à deux égards: d'une part elle explore un principe de passage en alternance des flux permettant de ne pas arrêter les véhicules aux intersections, et d'autre part, elle propose des algorithmes d'optimisationdistribuée de ce passage alterné au niveau de chaque intersection et au niveau du réseau global. La thèse présente successivement les choix de modélisation, les algorithmes et l'étude en simulation de leurs performances comparées à desapproches existantes
In this thesis, we focus on traffic coordination and optimization in road intersections, while accounting for intelligent autonomous vehicles. This thesis is organized in two parts. The first part focuses on the problem of sharing a one-lane road between two opposite flows of vehicles. The state of the art shows few studies addressing this issue. We propose two reactive coordination approaches that minimize vehicle delays and measure their performances statistically through simulations. The second part of the thesis addresses the problem of generic traffic management in a traffic network. We develop a stop-free approach that explores a principle alternating vehicles between flows at intersections, and it provides distributed algorithms optimizing this alternation at each intersection and in the overall network. We present the modeling choices, the algorithms and the simulation study of our approach and we compare its performances with existing approaches

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36

Staffolani, Alessandro. "A Reinforcement Learning Agent for Distributed Task Allocation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20051/.

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Al giorno d'oggi il reinforcement learning ha dimostrato di essere davvero molto efficace nel machine learning in svariati campi, come ad esempio i giochi, il riconoscimento vocale e molti altri. Perciò, abbiamo deciso di applicare il reinforcement learning ai problemi di allocazione, in quanto sono un campo di ricerca non ancora studiato con questa tecnica e perchè questi problemi racchiudono nella loro formulazione un vasto insieme di sotto-problemi con simili caratteristiche, per cui una soluzione per uno di essi si estende ad ognuno di questi sotto-problemi. In questo progetto abbiamo realizzato un applicativo chiamato Service Broker, il quale, attraverso il reinforcement learning, apprende come distribuire l'esecuzione di tasks su dei lavoratori asincroni e distribuiti. L'analogia è quella di un cloud data center, il quale possiede delle risorse interne - possibilmente distribuite nella server farm -, riceve dei tasks dai suoi clienti e li esegue su queste risorse. L'obiettivo dell'applicativo, e quindi del data center, è quello di allocare questi tasks in maniera da minimizzare il costo di esecuzione. Inoltre, al fine di testare gli agenti del reinforcement learning sviluppati è stato creato un environment, un simulatore, che permettesse di concentrarsi nello sviluppo dei componenti necessari agli agenti, invece che doversi anche occupare di eventuali aspetti implementativi necessari in un vero data center, come ad esempio la comunicazione con i vari nodi e i tempi di latenza di quest'ultima. I risultati ottenuti hanno dunque confermato la teoria studiata, riuscendo a ottenere prestazioni migliori di alcuni dei metodi classici per il task allocation.

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Rochefort, Yohan. "Méthodes pour le guidage coopératif." Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00934428.

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L'objectif de cette thèse est de définir puis d'étudier les performances de méthodes de guidage coopératif de véhicules aériens autonomes. L'intérêt du guidage coopératif est de confier une mission complexe à une flotte, plutôt qu'à un véhicule unique, afin de distribuer la charge de travail et d'améliorer les performances et la fiabilité. Les lois de guidage étudiées sont distribuées sur l'ensemble des véhicules afin d'une part, de répartir la charge de calcul et d'autre part, d'augmenter la fiabilité en éliminant la possibilité de perte de l'organe central de calcul de la commande.La première partie de la thèse porte sur les possibilités offertes par la règle des plus proches voisins. La loi de guidage développée consiste à ce que la commande de chaque véhicule soit élaborée en combinant les états des véhicules voisins. Afin de transmettre des consignes au groupe de véhicules, des objets dénommés agents virtuels sont introduits. Ceux-ci permettent de représenter des obstacles, d'indiquer une direction ou une cible au groupe de véhicules en utilisant des mécanismes déjà présent dans la loi de guidage.La seconde partie de la thèse porte sur les possibilités offertes par la commande prédictive. Ce type de commande consiste à employer un modèle du comportement du système afin de prédire les effets de la commande, et ainsi de déterminer celle qui minimise un critère de coût en respectant les contraintes du système. La loi de guidage développée emploi un critère de coût tenant compte et arbitrant entre les différents aspects de la mission (sécurité, progression de la mission, modération de la commande), et une procédure de recherche de la commande utilisant jeu prédéfinis de commandes candidates afin d'explorer l'espace de commande de manière efficace. Cette procédure, distincte des algorithmes d'optimisation habituels, génère une charge de calcul faible et constante, ne nécessite pas d'étape d'initialisation et est très peu sensible aux minima locaux.

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38

Sellem, Philippe. "Repartition de la perception dans un systeme distribue de robots autonomes." Paris 6, 2001. http://www.theses.fr/2001PA066372.

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Nous presentons une architecture de controle de robots mobiles cooperatifs destines a une utilisation en milieu hostile. Chaque robot est anime par un systeme multiagent compose d'elements dedies a des taches particulieres (perception, action, attention, selection de comportement, communication). Cette architecture possede l'originalite de permettre a des robots de fonctionner soit individuellement en mode autonome soit en cooperation avec d'autres robots, en particulier au niveau de la perception de l'environnement. Le partage de la perception a pour objectif principal, d'assurer l'extension du champ de perception des robots et de leur offrir un plus vaste horizon de perspectives. Mais cela doit egalement permettre a des unites de fonctionner malgre certains dommages (capteurs en panne ou neutralises) et ainsi d'envisager une activite en mode degrade par la prise en compte d'une perception suppletive.

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39

Rahman, Md Mustafizur. "Microgrid frequency control using multiple battery energy storage system (BESSs)." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/90856/1/MD%20Mustafizur_Rahman_Thesis.pdf.

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The work is a report of research on using multiple inverters of Battery Energy Storage Systems with angle droop controllers to share real power in an isolated micro grid system consisting of inertia based Distributed Generation units and variable load. The proposed angle droop control method helps to balance the supply and demand in the micro grid autonomous mode through charging and discharging of the Battery Energy Storage Systems while ensuring that the state of charge of the storage devices is within safe operating conditions. The proposed method is also studied for its effectiveness for frequency control. The proposed control system is verified and its performance validated with simulation software MATLAB/SIMULINK.

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40

Ruini, Fabio. "Distributed control for collective behaviour in micro-unmanned aerial vehicles." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1549.

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The work presented herein focuses on the design of distributed autonomous controllers for collective behaviour of Micro-unmanned Aerial Vehicles (MAVs). Two alternative approaches to this topic are introduced: one based upon the Evolutionary Robotics (ER) paradigm, the other one upon flocking principles. Three computer simulators have been developed in order to carry out the required experiments, all of them having their focus on the modelling of fixed-wing aircraft flight dynamics. The employment of fixed-wing aircraft rather than the omni-directional robots typically employed in collective robotics significantly increases the complexity of the challenges that an autonomous controller has to face. This is mostly due to the strict motion constraints associated with fixed-wing platforms, that require a high degree of accuracy by the controller. Concerning the ER approach, the experimental setups elaborated have resulted in controllers that have been evolved in simulation with the following capabilities: (1) navigation across unknown environments, (2) obstacle avoidance, (3) tracking of a moving target, and (4) execution of cooperative and coordinated behaviours based on implicit communication strategies. The design methodology based upon flocking principles has involved tests on computer simulations and subsequent experimentation on real-world robotic platforms. A customised implementation of Reynolds’ flocking algorithm has been developed and successfully validated through flight tests performed with the swinglet MAV. It has been notably demonstrated how the Evolutionary Robotics approach could be successfully extended to the domain of fixed-wing aerial robotics, which has never received a great deal of attention in the past. The investigations performed have also shown that complex and real physics-based computer simulators are not a compulsory requirement when approaching the domain of aerial robotics, as long as proper autopilot systems (taking care of the ”reality gap” issue) are used on the real robots.

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41

Bautista, Ruiz Esteban. "Laplacian Powers for Graph-Based Semi-Supervised Learning." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEN081.

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Les techniques d’apprentissage semi-supervisé basées sur des graphes (G-SSL) permettent d’exploiter des données étiquetées et non étiquetées pour construire de meilleurs classifiers. Malgré de nombreuses réussites, leur performances peuvent encore être améliorées, en particulier dans des situations ou` les graphes ont une faible séparabilité de classes ou quand le nombres de sujets supervisés par l’expert est déséquilibrés. Pour aborder ces limitations on introduit une nouvelle méthode pour G-SSL, appel´ee Lγ -PageRank, qui constitue la principal contribution de cette th`ese. Il s’agit d’une g´en´eralisation de l’algorithme PageRank ´a partir de l’utilisation de puissances positives γ de la matrice Laplacienne du graphe. L’étude théorique de Lγ -PageRank montre que (i) pour γ < 1, cela correspond `a une extension de l’algorithme PageRank aux processus de vol de L´evy: ou` les marcheurs aléatoires peuvent désormais relier, en un seul saut, des nœuds distants du graphe; et (ii) pour γ > 1, la classification est effectué sur des graphes signés: ou` les nœuds appartenant `a une même classe ont plus de chances de partager des liens positifs, tandis que les nœuds de classes différentes ont plus de chances d’être connectés avec des arêtes négatifs. Nous montrons l’existence d’une puissance optimale γ qui maximise la performance de classification, pour laquelle une méthode d’estimation automatique est conçue et évaluée. Des expériences sur plusieurs jeux de données montrent que les marcheurs aléatoires de vols de Lévy peuvent améliorer la détection des classes ayant des structures locales complexes, tandis que les graphes signés permet d’améliorer considérablement la séparabilité des données et de surpasser le problème des données étiquetées non équilibrées. Dans un second temps, nous étudions des implémentations efficaces de Lγ -PageRank. Nous proposons des extensions de Power Iteration et Gauss-Southwell pour Lγ -PageRank, qui sont des algorithmes initialement conçues pour calculer efficacement la solution de la méthode PageRank standard. Ensuite, les versions dynamiques de ces algorithmes sont également étendues à Lγ -PageRank, permettant de mettre `a jour la solution de Lγ -PageRank en complexité sub-linéaire lorsque le graphe évolue ou que de nouvelles données arrivent. Pour terminer, nous appliquons Lγ -PageRank dans le contexte du routage Internet. Nous abordons le problème de l’identification des systèmes autonomes (AS) pour des arêtes inter-AS `a partir du réseau d’adresses IP et des registres publics des AS. Des expériences sur des mesures traceroute d’Internet montrent que Lγ -PageRank peut résoudre cette tâche sans erreurs, même lorsqu’il n’y a pas d’exemples étiquetés par l’expert pour la totalité des classes
Graph-Based Semi-Supervised Learning (G-SSL) techniques learn from both labelled and unla- belled data to build better classifiers. Despite successes, its performance can still be improved, particularly in cases of graphs with unclear clusters or unbalanced labelled datasets. To ad- dress such limitations, the main contribution of this dissertation is a novel method for G-SSL referred to as the Lγ -PageRank method. It consists of a generalization of the PageRank algo- rithm based on the positive γ-th powers of the graph Laplacian matrix. The theoretical study of Lγ -PageRank shows that (i) for γ < 1, it corresponds to an extension of the PageRank algo- rithm to L´evy processes: where random walkers can now perform far-distant jumps in a single step; and (ii) for γ > 1, it operates on signed graphs: where nodes belonging to one same class are more likely to share positive edges while nodes from different classes are more likely to be connected with negative edges. We show the existence of an optimal γ-th power that maximizes performance, for which a method for its automatic estimation is devised and assessed. Exper- iments on several datasets demonstrate that the L´evy flight random walkers can enhance the detection of classes with complex local structures and that the signed graphs can significantly improve the separability of data and also override the issue of unbalanced labelled data. In addition, we study efficient implementations of Lγ -PageRank. Extensions of Power Iteration and Gauss-Southwell, successful algorithms to efficiently compute the solution of the standard PageRank algorithm, are derived for Lγ -PageRank. Moreover, the dynamic versions of Power Iteration and Gauss-Southwell, which can update the solution of standard PageRank in sub- linear complexity when the graph evolves or new data arrive, are also extended to Lγ -PageRank. Lastly, we apply Lγ -PageRank in the context of Internet routing. We address the problem of identifying the Autonomous Systems (AS) of inter-AS links from the network of IP addresses and AS public registers. Experiments on tracerout measurements collected from the Internet show that Lγ -PageRank can solve this inference task with no errors, even when the expert does not provide labelled examples of all classes

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Alsayasneh, Maha. "On the identification of performance bottlenecks in multi-tier distributed systems." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALM009.

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De nos jours, les systèmes distribués sont constitués de nombreuxcomposants logiciels ayant des interactions complexes et de nombreusespossibilités de configurations. Dès lors, localiser les problèmes deperformance est une tâche difficile, nécessitant une expertisehumaine et de nombreux essais. En effet, la même pile logicielle peutse comporter différemment en fonction dumatériel utilisé, de la logique applicative, des paramètres deconfiguration et des conditions de fonctionnement. Ce travail a pourobjectif (i) d’identifier un ensemble demétriques de référence, générales etfiables, pour localiser les problèmes de performance, (ii) d’identifierles caractéristiques de ces indicateurs, et (iii) deconstruire un outil qui puisse déterminer de manière automatiquesi le système a atteint sa capacité maximale en terme dedébit.Dans cette thèse, nous présentons trois contributionsprincipales. Premièrement, nous présentons une étude analytique d’ungrand nombre de configurations réalistes d’applications distribuéesmulti-tiers, se concentrant sur les chaînes de traitements desdonnées. En analysant un grand nombre de métriques au niveau logicielet matériel, nous identifions celles dont le comportement change aumoment où le système atteint sa capacité maximale. Deuxièmement, nousexploitons les techniques d’apprentissage machine pour développer unoutil capable d’identifier automatiquement les problèmes deperformance dans la chaîne de traitement de données. Pour ce faire,nous évaluons plusieurs techniques d’apprentissage machine, plusieurssélections de métriques, et différentscas de généralisation pour de nouvelles configurations. Troisièmement,pour valider les résultats obtenues sur la chaîne de traitement dedonnées, nous appliquons notre approche analytique et notre approchefondée sur l'apprentissage machine au cas d’une architecture Web.Nous tirons plusieurs conclusions de nos travaux. Premièrement, il estpossible d’identifier des métriques clés qui sont des indicateursfiables de problèmes de performance dans les systèmes distribuésmulti-tiers. Plus précisément, identifier le moment où le serveur aatteint sa capacité maximale peut être identifier grâce à cesmétriques fiables. Contrairement à l’approche adoptée par de nombreuxtravaux existants, nos travaux démontrent qu'une combinaison demétriques de différents types est nécessaire pour assurer uneidentification fiable des problèmes de performance dans un grandnombre de configurations. Nos travaux montrent aussi que les approchesfondées sur des méthodes d’apprentissage machine pour analyser lesmétriques permettent d’identifier les problèmes de performance dansles systèmes distribués multi-tiers. La comparaison de différentsmodèles met en évidence que ceux utilisant les métriques fiablesidentifiées par notre étude analytique sont ceux qui obtiennent lameilleure précision. De plus, notre analyse approfondie montre larobustesse des modèles obtenues. En effet, ils permettent unegénéralisation à de nouvelles configurations, à de nouveaux nombres declients, et à de nouvelles configurations exécutées avec de nouveauxnombres de clients. L'extension de notre étude au cas d'unearchitecture Web confirme les résultats principaux obtenus à traversl’étude sur la chaîne de traitement de données. Ces résultats ouvrentla voie à la construction d'un outil générique pour identifier demanière fiable les problèmes de performance dans les systèmesdistribués
Today's distributed systems are made of various software componentswith complex interactions and a large number of configurationsettings. Pinpointing the performance bottlenecks is generally a non-trivial task, which requires human expertise as well as trial anderror. Moreover, the same software stack may exhibit very differentbottlenecks depending on factors such as the underlying hardware, theapplication logic, the configuration settings, and the operatingconditions. This work aims to (i) investigate whether it is possibleto identify a set of key metrics that can be used as reliable andgeneral indicators of performance bottlenecks, (ii) identify thecharacteristics of these indicators, and (iii) build a tool that canautomatically and accurately determine if the system reaches itsmaximum capacity in terms of throughput.In this thesis, we present three contributions. First, we present ananalytical study of a large number of realistic configuration setupsof multi-tier distributed applications, more specifically focusing ondata processing pipelines. By analyzing a large number of metrics atthe hardware and at the software level, we identify the ones thatexhibit changes in their behavior at the point where the systemreaches its maximum capacity. We consider these metrics as reliableindicators of performance bottlenecks. Second, we leverage machinelearning techniques to build a tool that can automatically identifyperformance bottlenecks in the data processing pipeline. We considerdifferent machine learning methods, different selections of metrics,and different cases of generalization to new setups. Third, to assessthe validity of the results obtained considering the data processingpipeline for both the analytical and the learning-based approaches,the two approaches are applied to the case of a Web stack.From our research, we draw several conclusions. First, it is possibleto identify key metrics that act as reliable indicators of performancebottlenecks for a multi-tier distributed system. More precisely,identifying when the server has reached its maximum capacity can beidentified based on these reliable metrics. Contrary to the approachadopted by many existing works, our results show that a combination ofmetrics of different types is required to ensure reliableidentification of performance bottlenecks in a large number ofsetups. We also show that approaches based on machine learningtechniques to analyze metrics can identify performance bottlenecks ina multi-tier distributed system. The comparison of different modelsshows that the ones based on the reliable metrics identified by ouranalytical study are the ones that achieve the bestaccuracy. Furthermore, our extensive analysis shows the robustness ofthe obtained models that can generalize to new setups, to new numbersof clients, and to both new setups and new numbers ofclients. Extending the analysis to a Web stack confirmsthe main findings obtained through the study of the data processingpipeline. These results pave the way towards a general and accuratetool to identify performance bottlenecks in distributed systems

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Hayakawa, Tomohiro. "Adaptation of a group to various environments through local interactions between individuals based on estimated global information." Kyoto University, 2020. http://hdl.handle.net/2433/259039.

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付記する学位プログラム名: グローバル生存学大学院連携プログラム
Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第22771号
工博第4770号
新制||工||1746(附属図書館)
京都大学大学院工学研究科機械理工学専攻
(主査)教授松野文俊, 教授椹木哲夫, 教授泉田啓
学位規則第4条第1項該当

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44

Taton, Christophe. "Vers l’auto-optimisation dans les systèmes autonomes." Grenoble INPG, 2008. http://www.theses.fr/2008INPG0183.

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La complexité croissante des systèmes informatiques rend l'administration des systèmes de plus en plus fastidieuse. Une approche à ce problème vise à construire des systèmes autonomes capables de prendre en charge eux-mêmes leur administration et de réagir aux changements de leur état et de leur environnement. Dans le contexte actuel de l'énergie rare et chère, l'optimisation des systèmes informatiques est un domaine d'administration fondamental pour améliorer leurs performances et réduire leur empreinte énergétique. Gros consommateurs d'énergie, les systèmes actuels sont statiquement configurés et réagissent assez mal aux évolutions de leur environnement, et notamment aux variations des charges de travail auxquelles ils sont soumis. L'auto-optimisation offre une réponse prometteuse à ces différents besoins en dotant les systèmes de la faculté d'améliorer leurs performances de manière autonome. Cette thèse se consacre à l'étude des algorithmes et mécanismes permettant de mettre en œuvre des systèmes autonomes auto-optimisés. Nous étudions plus particulièrement les algorithmes d'auto-optimisation fondés sur l'approvisionnement dynamique des systèmes afin d'en améliorer les performances et de maximiser le rendement des ressources. Dans le cadre du prototype Jade, plate-forme d'administration autonome à base de composants, nous proposons des algorithmes qui améliorent au mieux les performances des systèmes administrés par des adaptations des systèmes en réponse à des variations progressives ou brutales des charges auxquelles ils sont soumis. Nous montrons l'efficacité de ces algorithmes sur des services Internet et des services à messages soumis à des charges variables. Enfin, dans le but de garantir des performances optimales, nous proposons également une politique d'optimisation qui repose sur une modélisation des systèmes administrés servant à l'élaboration de configurations optimales. Cette politique fait l'objet d'une évaluation sur un service de surveillance d'une infrastructure distribuée. L'implantation de politiques d'administration autonome fait apparaître un certain nombre de défis en induisant diverses contraintes : le système doit être capable d'adaptation dynamique, de s'observer et de se manipuler. En réponse à ces besoins, nous nous appuyons sur le langage Oz et sa plateforme distribuée Mozart pour implanter FructOz, un canevas spécialisé dans la construction et la manipulation de systèmes à architectures distribuées dynamiques complexes, et LactOz, une bibliothèque d'interrogation des architectures dynamiques. En combinant FructOz et LactOz, on montre comment implanter des systèmes dynamiques complexes impliquant des déploiements distribués avec un haut niveau de paramétrage et de synchronisation
The increasing complexity of computer systems makes their administration even more tedious and error-prone. A general approach to this problem consists in building autonomic systems that are able to manage themselves and to handle changes of their state and their environment. While energy becomes even more scarce and expensive, the optimization of computer systems is an essential management field to improve their performance and to reduce their energetic footprint. As huge energy consumers, current computer systems are usually statically configured and behave badly in response to changes of their environment, and especially to changes of their workload. Self-optimization appears as a promising approach to these problems as it endows these systems with the ability to improve their own performance in an autonomous manner. This thesis focuses on algorithms and techniques to implement self-optimized autonomic systems. We specifically study self-optimization algorithms that rely on dynamic system provisioning in order to improve their performance and their resources’ efficiency. In the context of the Jade prototype of a component-based autonomic management platform, we propose best-effort algorithms that improve the performance of the managed systems through dynamic adaptations of the systems in response to gradual or sudden changes of their workload. We show the efficiency of these algorithms on Internet services and on messages services submitted to changing workloads. Finally, in order to guarantee optimal performance, we propose an optimization policy relying on the modelling of the managed system so as to generate optimal configurations. This policy is evaluated on a monitoring service for distributed systems. The implementation of autonomic management policies raised a number of challenges: the system is required to support dynamic adaptions, to observe itself and to take actions on itself. We address these needs with the Oz programming language and its distributed platform Mozart to implement the FructOz framework dedicated to the construction and handling of complex dynamic and distributed architecture-based systems, and the LactOz library specialized in the querying and browsing of dynamic architectures. Combining FructOz and LactOz, we show how to build complex dynamic systems involving distributed deployments as well as high levels of synchronizations and parameters

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Moussa, Hassan. "Contribution to the Decentralized Energy Management of Autonomous AC-Microgrid." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0161/document.

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Cette thèse porte sur des micro-réseaux AC isolées qui permettent l’intégration des ressources énergétiques distribuées (DER) pouvant fournir leur énergie d'alimentation existante de manière contrôlée pour assurer le bon fonctionnement global du système. L'interconnexion d'un DER à une micro-réseau s'effectue habituellement en utilisant un convertisseur d'interface distribué (DIC) (i.e. un bloc d'interface d'électronique de puissance générale) qui est constitué d’un module de convertisseur à l'entrée de la source, un onduleur de tension (VSI), un module d'interfaçage de sortie, et le module de commande. Dans cette thèse on réalise plusieurs lois de commande basées sur des méthodes décentralisées. L'accent principal est mis sur les fonctions "Droop" qui ont la tâche de maintenir un équilibre de distribution d'énergie entre les différentes sources énergétiques connectées à la micro-réseau. L'objectif est d'assurer la stabilité du système et d’améliorer les performances dynamiques en partageant la puissance entre les différents générateurs d’électricité distribués (DGs) en fonction de leur puissance nominale. Le développement d'une analyse de stabilité en boucle fermée s’avère utile pour étudier la dynamique du système afin d'obtenir une réponse transitoire souhaitée qui permet d'identifier les paramètres de contrôle de boucle appropriés. L'amélioration de la qualité d’énergie des micro-réseaux est également un objectif de cette thèse. La réduction des distorsions harmoniques de la tension de sortie en présence de charges linéaires et non linéaires est prise en compte dans nos travaux. D'autres aspects seront étudiés sur la façon de traiter les charges constantes connectées au réseau et les grandes perturbations qu’ils produisent. Cela donne lieu à d'autres études de recherche portant sur la stabilité grand signal des micro-réseaux
This thesis deals with islanded AC microgrid that allows any integration of Distributed Energy Resources (DERs) that may provide their existing supply energy in a controlled manner to insure overall system functioning. The interconnection of a DER to a microgrid is done usually by using a Distributed Interface Converter (DIC), a general power electronics interface block, which consists of a source input converter module, a Voltage Source Inverter module (VSI), an output interface module, and the controller module. The thesis realizes several control laws based on decentralized methods. The major focus is on the Droop functions that are responsible for providing a power distribution balance between different Energy Resources connected to a microgrid. The aim is to insure system stability and better dynamic performance when sharing the power between different DGs as function to their nominal power. Developing a closed loop stability analysis is useful for studying system dynamics in order to obtain a desired transient response that allows identifying the proper loop control parameters. Power Quality enhancement in microgrids is also a purpose of this research. The reduction of harmonic distortions of the output voltage when supplying linear and non-linear loads are taken in consideration in this thesis. Further aspects will be studied about how to deal with constant power loads connected to the grid and the large perturbations exerted. This results to further research studies that deal with large-signal stability of microgrids

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Kim, Taewan. "Linewidth and Ranging Characterization of a Vernier-Tuned Distributed Bragg Reflector (Vt-Dbr) All-Semiconductor Tunable Swept Laser System for Lidar in Autonomous Applications." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1770.

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ABSTRACT Linewidth and Ranging Characterization of a Vernier-Tuned Distributed Bragg Reflector (VT-DBR) All-Semiconductor Tunable Swept Laser System for Lidar in Autonomous Applications Taewan Kim Linewidth and ranging experiments of a Insight packaged Vernier-Tuned Distributed Bragg Reflector (VT-DBR) laser across its wavelength output range of 1522.13 to 1566.18 nm is done in this work to characterize it for lidar applications. The purpose of this paper is to investigate the laser’s potential to combine the advantages of lidar and FMCW radar for autonomous systems. Linewidth measurements were done by using a Mach-Zehnder interferometer to set up a delayed self-homodyne measurement. The laser was set to output at a fixed wavelength across a range of 1523 to 1566 nm in 1 nm increments, and linewidth was captured each of these increments. For each of the linewidths, coherence time and length along with laser currents were associated. The minimum linewidth found in this test was found to be 50 MHz, leading to a maximum coherence time of 6.366 ns and a maximum coherence length of 129.92 cm. There was a somewhat linear, albeit low correlation, area of low linewidths depending on the front mirror and back mirror currents across the wavelength range. Initial ranging experiments were performed using interference fringes caused by variable stationary path length differences introduced into a homemade Mach-Zehnder interferometer around the coherence lengths found in the linewidth test. The experimental path length differences indicated by the interference fringes seem to be accurate at very small ruler measured path length differences, but starts to stray away from the ruler measured as the path length differences get larger. Data taken suggests that there is a mathematical relationship in the error between the ruler measured and experimental path length differences leading to the belief that this error can be compensated for. Keywords: Vernier-Tuned Distributed Bragg Reflector, VT-DBR, FMCW, linewidth, coherence, self-homodyne, Mach-Zehnder Interferometer, interference fringes

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Awni, S. H. "Control and communication in developing countries : a cybernetic analysis and a proposed solution, exemplified by a distributed database system for the implementation of a national plan." Thesis, Brunel University, 1985. http://bura.brunel.ac.uk/handle/2438/4999.

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This thesis proposes some enhancements of the control and communication aspects of the implementation of a National Plan in any developing country. A cybernetic model for the viable system is used following the approach developed by Beer. Weaknesses of typical current practice are identified and a hierarchical organization, based on the model, is suggested as an alternative, in which all the systems implementing and monitoring the N. P. are considered as one single system, making its functions easier to recognize. Deficiencies, which are characteristic of the situation of developing countries, are identified and remedies are suggested to increase effectiveness. The model provides for the cybernetic principle of freedom, allowing the creation of autonomous subsystems with their own computational needs. A distributed system using micros, databases, and national communication networks, is described, which provides the requirements for realizing the suggested organization, together with packaged software to compensate for missing experience and know-how. The proposals are made in the form of a comprehensive package whose built-in complexity (sophistication) is very high. It is still effective even with inexperienced users but can take full advantage of their developing knowledge. This thesis includes listings and sample runs of some portions of the package which, for purposes of demonstration, have been implemented in dBASE II and an 8080 assembly program on an Intertec Superbrain QD microcomputer.

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Wathugala, Wathugala Gamage Dulan Manujinda. "Formal Modeling Can Improve Smart Transportation Algorithm Development." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22608.

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201 pages
Ensuring algorithms work accurately is crucial, especially when they drive safety critical systems like self-driving cars. We formally model a published distributed algorithm for autonomous vehicles to collaborate and pass thorough an intersection. Models are built and validated using the “Labelled Transition System Analyser” (LTSA). Our models reveal situations leading to deadlocks and crashes in the algorithm. We demonstrate two approaches to gain insight about a large and complex system without modeling the entire system: Modeling a sub system - If the sub system has issues, the super system too. Modeling a fast-forwarded state - Reveals problems that can arise later in a process. Some productivity tools developed for distributed system development are also presented. Manulator, our distributed system simulator, enables quick prototyping and debugging on a single workstation. LTSA-O, extension to LTSA, listens to messages exchanged in an execution of a distributed system and validates it against a model.

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Costache, Stefania. "Gestion autonome des ressources et des applications dans un nuage informatique selon une approche fondée sur un marché." Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00925352.

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Les organisations qui possèdent des infrastructures de calcul à haute performance (HPC) font souvent face à certaines difficultés dans la gestion de leurs ressources. En particulier, ces difficultés peuvent provenir du fait que des applications de différents types doivent pouvoir accéder concurremment aux ressources tandis que les utilisateurs peuvent avoir des objectifs de performance (SLOs) variés. Pour atteindre ces difficultés, cette thèse propose un cadre générique et extensible pour la gestion autonome des applications et l'allocation dynamique des ressources. L'allocation des ressources et l'exécution des applications est régie par une économie de marché observant au mieux des objectifs de niveau de service (SLO) tout en tirant avantage de la flexibilité d'une nuage informatique et en maximisant l'utilisation de des ressources. Le marché fixe dynamiquement un prix aux ressources, ce qui, combiné avec une politique de distribution de monnaie entre les utilisateurs, en garantit une utilisation équitable. Simultanément, des contrôleurs autonomes mettent en oeuvre des politiques d'adaptation pour faire évoluer la demande en ressource de leur application en accord avec la SLO requise par l'utilisateur. Les politiques d'adaptation peuvent : (i) adapter dynamiquement leur demande en terme de CPU et de mémoire demandés en période de contention de ressource aux machines virtuelles (ii) et changer dynamiquement le nombre de machines virtuelle. Nous avons évalué cette plateforme au moyen de la simulation et sur l'infrastructure Grid'5000. Nos résultats ont montré que cette solution: (i) offre un support plus flexible aux applications de type différent demandant divers niveaux de service; (ii) conduit à une bonne satisfaction des utilisateurs moyennant une dégradation acceptable des performances comparées aux solutions centralisées existantes.

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Durand, Stéphane. "Analysis of Best Response Dynamics in Potential Games." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAM096.

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Dans le contexte de la théorie des jeux, les équilibres de Nash, ie les états dans lesquels aucun joueur ne peut augmenter son utilité en changeant sa stratégie unilatéralement, sont une des formes principales de solutions des jeux. Ils sont les états les plus probables rencontrés lors de l’évolution des systèmes, des points de stabilité, et sont l'objet de nombreuse propriétés utiles ( le prix de l'anarchie bornant la distance à un optimum du jeu, par exemple). La classe des jeux de potentiels est une large sous classe des jeux incluant entre autre tous les jeux de congestions, et permettant de modéliser un grand nombre de problèmes. dans cette classe, il est difficile de trouver un équilibre de Nash: ce problème est PLS -complet, PLS étant une classe de complexité située entre P et NP. La dynamique de meilleure réponse, un algorithme glouton assez simple utilisé initialement comme outil de preuve pour montrer l'existence d'équilibre de Nash dans tous jeux, admet une complexité en pire cas exponentielle en le nombre de joueurs. En conséquence, cette dynamique n'est pas considérée un outil efficace pour obtenir un équilibre. Dans cette thèse, nous allons montrer que cet algorithme est efficace et robuste, selon le critère de l'analyse en moyenne. Dans le cas le plus simple, on obtient une borne linéaire sur le temps moyen avant convergence, a l'aide d'une approximation par une chaîne de Markov qui peut être résolue analytiquement. Cette approche montre que la dynamique de meilleure réponse reste efficace pour des conditions d'utilisation beaucoup plus générales. Cela inclus les systèmes distribués (des joueurs indépendants, chacun ayant peu de connaissances sur les états des autres) avec une borne en O(n log n), ainsi que les systèmes dans lesquels les joueurs ne connaissent pas leurs utilités avec une borne du même ordre. Cette approche montre également comment profiter d'une structure de type réseau pour obtenir une complexité fonction du nombre de voisins au lieu du nombre de joueurs
In game theory, Nash equilibria, the states where no players can gain by unilaterally changing their strategy, are one of the main notions of solution of the games. nash equilibria are the most likely states at equilibrium, they are also stable and in many context they have properties guaranteeing being near the optimums. We focus on potential games, a subclass of the gameswhich include among other all congestion games and routing games. Even restricted on the class of potential games, finding a Nash equilibrium is difficult. This problem is in fact PLS-complete, which is a class between P and NP. Best response dynamics, are a greedy algorithm, which were first devised as a tool for proving existence of a Nash equilibrium. Their worst-case complexity is exponential with respect to the number of players. they were also though to need their players acting strictly one after the others to ensure convergence. as such they do not appears as an efficient algorithm for actually computing an equilibrium. However, in this thesis we will show that the condition to ensure convergence is more permissive than separates players, and that this algorithm is efficient when considered through average complexity: When averaging over the set of all potential games, we can obtain a linear bound on the basic version. In order to obtain this result, we apply a Markovian approximation allowing us to solve the system analytically. This approach also shows that the best response dynamics are robust, they stay efficient under much wider conditions of application. This include distributed system, with independent actors with little knowledge of each other, with a bound in O(n log n). It can also take into account instances where players do not know their utilities, getting a similar bound. This approach also shows how to benefit from a network structure on the game to get a complexity based on the number of neighbors of the players instead of the number of players

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Dissertations / Theses on the topic 'Autonomous distributed systems'

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