22 research outputs found

    A general framework integrating techniques for scheduling under uncertainty

    Get PDF
    Ces derniĂšres annĂ©es, de nombreux travaux de recherche ont portĂ© sur la planification de tĂąches et l'ordonnancement sous incertitudes. Ce domaine de recherche comprend un large choix de modĂšles, techniques de rĂ©solution et systĂšmes, et il est difficile de les comparer car les terminologies existantes sont incomplĂštes. Nous avons cependant identifiĂ© des familles d'approches gĂ©nĂ©rales qui peuvent ĂȘtre utilisĂ©es pour structurer la littĂ©rature suivant trois axes perpendiculaires. Cette nouvelle structuration de l'Ă©tat de l'art est basĂ©e sur la façon dont les dĂ©cisions sont prises. De plus, nous proposons un modĂšle de gĂ©nĂ©ration et d'exĂ©cution pour ordonnancer sous incertitudes qui met en oeuvre ces trois familles d'approches. Ce modĂšle est un automate qui se dĂ©veloppe lorsque l'ordonnancement courant n'est plus exĂ©cutable ou lorsque des conditions particuliĂšres sont vĂ©rifiĂ©es. Le troisiĂšme volet de cette thĂšse concerne l'Ă©tude expĂ©rimentale que nous avons menĂ©e. Au-dessus de ILOG Solver et Scheduler nous avons implĂ©mentĂ© un prototype logiciel en C++, directement instanciĂ© de notre modĂšle de gĂ©nĂ©ration et d'exĂ©cution. Nous prĂ©sentons de nouveaux problĂšmes d'ordonnancement probabilistes et une approche par satisfaction de contraintes combinĂ©e avec de la simulation pour les rĂ©soudre. ABSTRACT : For last years, a number of research investigations on task planning and scheduling under uncertainty have been conducted. This research domain comprises a large number of models, resolution techniques, and systems, and it is difficult to compare them since the existing terminologies are incomplete. However, we identified general families of approaches that can be used to structure the literature given three perpendicular axes. This new classification of the state of the art is based on the way decisions are taken. In addition, we propose a generation and execution model for scheduling under uncertainty that combines these three families of approaches. This model is an automaton that develops when the current schedule is no longer executable or when some particular conditions are met. The third part of this thesis concerns our experimental study. On top of ILOG Solver and Scheduler, we implemented a software prototype in C++ directly instantiated from our generation and execution model. We present new probabilistic scheduling problems and a constraintbased approach combined with simulation to solve some instances thereof

    BLOCKS, a Component Framework with Checking Facilities for Knowledge-Based Systems

    Get PDF
    Ă©quipe PULSARInternational audienceBLOCKS is an answer to the software engineering needs of the design of knowledge-based system engines. It is a framework composed of reusable and adaptable software components. However , its safe and correct use is complex and we supply formal models and associated tools to assist using it. These models and tools are based on behavioral description of components and on model checking techniques. They ensure a safe reuse of the components, especially when extending them through inheritance, owing to the notion of behavioral refinement

    Differential Evolution Algorithm in the Construction of Interpretable Classification Models

    Get PDF
    In this chapter, the application of a differential evolution-based approach to induce oblique decision trees (DTs) is described. This type of decision trees uses a linear combination of attributes to build oblique hyperplanes dividing the instance space. Oblique decision trees are more compact and accurate than the traditional univariate decision trees. On the other hand, as differential evolution (DE) is an efficient evolutionary algorithm (EA) designed to solve optimization problems with real-valued parameters, and since finding an optimal hyperplane is a hard computing task, this metaheuristic (MH) is chosen to conduct an intelligent search of a near-optimal solution. Two methods are described in this chapter: one implementing a recursive partitioning strategy to find the most suitable oblique hyperplane of each internal node of a decision tree, and the other conducting a global search of a near-optimal oblique decision tree. A statistical analysis of the experimental results suggests that these methods show better performance as decision tree induction procedures in comparison with other supervised learning approaches

    Imprecise data fusion

    Get PDF
    Possibility theory offers a natural setting for representing imprecise data and poor information. This theory turns out to be quite useful for the purpose of pooling pieces of information stemming from several sources (for instance, several experts, sensors, or databases) . Indeed it looks more flexible than probability theory for the representation of aggregation modes that do not express averaging processes . This paper tentatively explains why possibility theory is appealing for the fusion of imprecise data, and it describes several aggregation modes it allows, along with their underlying assumptions . The existence of adaptive combination rules are pointed out, that take into account the level of conflict between the sources . This approach sounds natural in the pooling of expert opinions . It is suggested here that, under some assumptions, it might also be useful in sensor data fusion .La thĂ©orie des possibilitĂ©s offre un cadre formel naturel pour la reprĂ©sentation de donnĂ©es imprĂ©cises, d'informations pauvres. Cette thĂ©orie prend tout son intĂ©rĂȘt quand il s'agit d'agrĂ©ger des informations issues de plusieurs sources (par exemple un groupe d'experts, un ensemble hĂ©tĂ©rogĂšne de capteurs, plusieurs bases de donnĂ©es). En effet elle s'avĂšre ĂȘtre beaucoup plus souple que la thĂ©orie des probabilitĂ©s pour dĂ©crire des modes d'agrĂ©gation qui ne correspondent pas Ă  des moyennes. Dans cet article on tente d'expliquer pourquoi la thĂ©orie des possibilitĂ©s est intĂ©ressante dans le problĂšme de fusion d'informations imprĂ©cises, et on dĂ©crit les modes d'agrĂ©gation qu'elle permet de reprĂ©senter, avec les hypothĂšses qui les sous-tendent. On indique notamment l'existence d'opĂ©rations de combinaison adaptatives qui prennent en compte le niveau de conflit entre les sources. Cette approche semble justifiĂ©e pour l'agrĂ©gation d'opinions d'experts. On suggĂšre ici qu'elle peut, dans certaines conditions, ĂȘtre utilisĂ©e pour la fusion multi-capteur

    Logic-based Technologies for Multi-agent Systems: A Systematic Literature Review

    Get PDF
    Precisely when the success of artiïŹcial intelligence (AI) sub-symbolic techniques makes them be identiïŹed with the whole AI by many non-computerscientists and non-technical media, symbolic approaches are getting more and more attention as those that could make AI amenable to human understanding. Given the recurring cycles in the AI history, we expect that a revamp of technologies often tagged as “classical AI” – in particular, logic-based ones will take place in the next few years. On the other hand, agents and multi-agent systems (MAS) have been at the core of the design of intelligent systems since their very beginning, and their long-term connection with logic-based technologies, which characterised their early days, might open new ways to engineer explainable intelligent systems. This is why understanding the current status of logic-based technologies for MAS is nowadays of paramount importance. Accordingly, this paper aims at providing a comprehensive view of those technologies by making them the subject of a systematic literature review (SLR). The resulting technologies are discussed and evaluated from two different perspectives: the MAS and the logic-based ones

    ContrÎle intelligent de la domotique à partir d'informations temporelles multi sources imprécises et incertaines

    Get PDF
    La Maison Intelligente est une rĂ©sidence Ă©quipĂ©e de technologie informatique qui assiste ses habitant dans les situations diverses de la vie domestique en essayant de gĂ©rer de maniĂšre optimale leur confort et leur sĂ©curitĂ© par action sur la maison. La dĂ©tection des situations anormales est un des points essentiels d'un systĂšme de surveillance Ă  domicile. Ces situations peuvent ĂȘtre dĂ©tectĂ©es en analysant les primitives gĂ©nĂ©rĂ©es par les Ă©tages de traitement audio et par les capteurs de l'appartement. Par exemple, la dĂ©tection de cris et de bruits sourds (chute d'un objet lourd) dans un intervalle de temps rĂ©duit permet d'infĂ©rer l'occurrence d'une chute. Le but des travaux de cette thĂšse est la rĂ©alisation d'un contrĂŽleur intelligent reliĂ© Ă  tous les pĂ©riphĂ©riques de la maison capable de rĂ©agir aux demandes de l'habitant (par commande vocale) et de reconnaĂźtre des situations Ă  risque ou dĂ©tresse. Pour accomplir cet objectif, il est nĂ©cessaire de reprĂ©senter formellement et raisonner sur des informations, le plus souvent temporelles, Ă  des niveaux d'abstraction diffĂ©rents. Le principale dĂ©fi est le traitement de l'incertitude, l'imprĂ©cision, et incomplĂ©tude, qui caractĂ©risent les informations dans ce domaine d'application. Par ailleurs, les dĂ©cisions prises par le contrĂŽleur doivent tenir compte du contexte dans lequel une ordre est donnĂ©, ce qui nous place dans l'informatique sensible au contexte. Le contexte est composĂ© des informations de haut niveau tels que la localisation, l'activitĂ© en cours de rĂ©alisation, la pĂ©riode de la journĂ©e. Les recherches prĂ©sentĂ©es dans ce manuscrit peuvent ĂȘtre divisĂ©s principalement en trois axes: la rĂ©alisation des mĂ©thodes d'infĂ©rence pour acquĂ©rir les informations du contexte(notamment, la localisation de l'habitant y l'activitĂ© en cours) Ă  partir des informations incertains, la reprĂ©sentation des connaissances sur l'environnement et les situations Ă  risque, et finalement la prise de dĂ©cision Ă  partir des informations contextuelles. La derniĂšre partie du manuscrit expose les rĂ©sultats de la validation des mĂ©thodes proposĂ©es par des Ă©valuations amenĂ©es Ă  la plateforme expĂ©rimental Domus.A smart home is a residence featuring ambient intelligence technologies in order to help its dwellers in different situations of common life by trying to manage their comfort and security through the execution of actions over the effectors of the house. Detection of abnormal situations is paramount in the development of surveillance systems. These situations can be detected by the analysis of the traces resulting from audio processing and the data provided by the network of sensors installed in the smart home. For instance, detection of cries along with thuds(fall of a heavy object) in a short time interval can help to infer that the resident has fallen. The goal of the research presented in this thesis is the implementation of an intelligence controller connected with the devices in the house that is able to react to user's commands(through vocal interfaces) and recognize dangerous situations. In order to fulfill this goal, it is necessary to create formal representation and to develop reasoning mechanism over informations that are often temporal and having different levels of abstraction. The main challenge is the processing the uncertainty, imprecision, and incompleteness that characterise this domain of application. Moreover, the decisions taken by the intelligent controller must consider the context in which a user command is given, so this work is made in the area of Context Aware Computing. Context includes high level information such as the location of the dweller, the activity she is making, and the time of the day. The research works presented in this thesis can be divided mainly in three parts: the implementation of inference methods to obtain context information(namely, location and activity) from uncertain information, knowledge representation about the environment and dangerous situations, and finally the development of decision making models that use the inferred context information. The last part of this thesis shows the results from the validation of the proposed methods through experiments performed in an experimental platform, the Domus apartment.SAVOIE-SCD - Bib.Ă©lectronique (730659901) / SudocGRENOBLE1/INP-Bib.Ă©lectronique (384210012) / SudocGRENOBLE2/3-Bib.Ă©lectronique (384219901) / SudocSudocFranceF

    Modified bargaining protocols for automated negotiation in open multi-agent systems

    Get PDF
    Current research in multi-agent systems (MAS) has advanced to the development of open MAS, which are characterized by the heterogeneity of agents, free exit/entry and decentralized control. Conflicts of interest among agents are inevitable, and hence automated negotiation to resolve them is one of the promising solutions. This thesis studies three modifications on alternating-offer bargaining protocols for automated negotiation in open MAS. The long-term goal of this research is to design negotiation protocols which can be easily used by intelligent agents in accommodating their need in resolving their conflicts. In particular, we propose three modifications: allowing non-monotonic offers during the bargaining (non-monotonic-offers bargaining protocol), allowing strategic delay (delay-based bargaining protocol), and allowing strategic ignorance to augment argumentation when the bargaining comprises argumentation (ignorance-based argumentation-based negotiation protocol). Utility theory and decision-theoretic approaches are used in the theoretical analysis part, with an aim to prove the benefit of these three modifications in negotiation among myopic agents under uncertainty. Empirical studies by means of computer simulation are conducted in analyzing the cost and benefit of these modifications. Social agents, who use common human bargaining strategies, are the subjects of the simulation. In general, we assume that agents are bounded rational with various degrees of belief and trust toward their opponents. In particular in the study of the non-monotonic-offers bargaining protocol, we assume that our agents have diminishing surplus. We further assume that our agents have increasing surplus in the study of delay-based bargaining protocol. And in the study of ignorance-based argumentation-based negotiation protocol, we assume that agents may have different knowledge and use different ontologies and reasoning engines. Through theoretical analysis under various settings, we show the benefit of allowing these modifications in terms of agents’ expected surplus. And through simulation, we show the benefit of allowing these modifications in terms of social welfare (total surplus). Several implementation issues are then discussed, and their potential solutions in terms of some additional policies are proposed. Finally, we also suggest some future work which can potentially improve the reliability of these modifications
    corecore