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Designing Budget-Balanced Best-Response Mechanisms for Network Coordination Games
No full textin Springer series Lecture Notes in Computer Science, vol. 8146Network coordination games (NCGs) have recently received a lot of attention since they model several kinds of interaction problems in social networks. However, the performance of these games at equilibrium may be very bad. This motivates the adoption of mechanisms for inducing a socially optimal state. Many settings are naturally dynamical and thus we believe it is worth to consider the design of incentive compatible best-response mechanisms (Nisan, Schapira, Valiant, Zohar, 2011) for NCGs. Specifically, we would like to assign to players special fees in order to induce the optimum profile of an NCG. Moreover, we would like the mechanism to be budget-balanced, i.e., implementable with no cost.We show that a budget-balanced and incentive compatible best- response mechanism for inducing the optimal profile of a two-strategy NCG always exists. Moreover, for such a mechanism, we investigate other properties inspired by envy-freeness, collusion-resistance and fairness.nonouirechercheInternationa
Sampling Methods in Genetic Programming Learners from Large Datasets: A Comparative Study
No full textin Advances in Intelligent Systems and Computing, vol. 529The amount of available data for data mining and knowledge discovery continue to grow very fast with the era of Big Data. Genetic Programming algorithms (GP), that are efficient machine learning techniques, are face up to a new challenge that is to deal with the mass of the provided data. Active Sampling, already used for Active Learning, might be a good solution to improve the Evolutionary Algorithms (EA) training from very big data sets. This paper present a review of sampling techniques already used with active GP learner and discuss their ability to improve the GP training from very big data sets. A method in each sampling strategy is implemented and applied on the KDD intrusion detection problem using very close parameters. Experimental results show that sampling methods outperforms results obtained with full dataset but some of them cannot be scaled to large datasets.nonouirechercheInternationa
A Knowledge-based Approach for Self-healing Service-oriented Applications
No full textIn the context of service-oriented applications, the self-healing property provides reliable execution in order to support failures and assist automatic recovery techniques. This paper presents a knowledge-based approach for self-healing Composite Service (CS) applications. A CS is an application composed by a set of services interacting each other and invoked on the Web. Our approach is supported by Service Agents, which are in charge of the CS fault-tolerance execution control, making decisions about the selection of recovery and proactive strategies. Service Agents decisions are based on the information they have about the whole application, about themselves, and about what it is expected and what it is really happening at run-time. Hence, application knowledge for decision making comprises off-line precomputed global and local information, user QoS preferences, and propagated actual run-time information. Our approach is evaluated experimentally using a case study.nonouirechercheInternationa
The Complexity of Finding Harmless Individuals in Social Networks
No full textIn this paper, we introduce a domination-related problem called Harmless Set: given a graph G=(V,E)G=(V,E), a threshold function t:V→Nt:V→N and an integer kk, find a subset of vertices V′⊆VV′⊆V of size at least kk such that every vertex vv in VV has less than t(v)t(v) neighbors in V′V′. We study its parameterized complexity and the approximation of the associated maximization problem. When the parameter is kk, we show that the problem is W[2]-complete in general and W[1]-complete if all thresholds are bounded by a constant. Moreover, we prove that, if P≠NPP≠NP, the maximization version is not View the MathML sourcen12−ε-approximable for any ε>0ε>0 even when all thresholds are at most two. When each threshold is equal to the degree of the vertex, we show that Harmless Set is fixed-parameter tractable for parameter kk and the maximization version is APX-complete. We give a polynomial-time algorithm for graphs of bounded treewidth and a polynomial-time approximation scheme for planar graphs. Finally, we show that the parametric dual problem (n−k)(n−k)-Harmless Set is fixed-parameter tractable for a large family of threshold functions.nonouirechercheInternationa
Modeling Snapshot of Composite WS Execution by Colored Petri Nets
No full textin Springer series Lecture Notes in Computer Science, vol. 8194The global transactional property of a Transactional Composite Web Service (TCWS) allows recovery processes if a Web Service (WS) fails during the execution process. The following actions can be performed if a WS fails: retry the faulty WS, substitute the faulty WS, or compensate the executed WSs. In consequence, these fault-tolerance mechanisms ensure the atomicity property of a TCWS with an all-or-nothing endeavor. In this paper, we present a formal definition of a checkpointing approach based in Colored Petri-Nets (CPNs) properties, in which the execution process and the actions performed in case of failures rely on unrolling processes of CPNs. Our checkpointing approach allows to relax the atomic transactional property of a TCWS in case of failures. The all-or-nothing transactional property becomes to the something-to-all property. A snapshot of the most possible advanced partial result is taken in case of failures and it is returned to the user (user gets something), providing the possibility of restarting the TCWS from an advanced execution state to complete the result (user gets all later), without affecting its original transactional property. We present the execution algorithms with the additionally capacity of taking snapshot in case of failures and experimental results to show the reception of partial outputs due to the relaxation of the all-or-nothing property.nonouirechercheInternationa
I’m worth it or I need it? Self-gift giving and consumers’ self-regulatory mindset
No full textPurpose – The aim of the research presented in this paper is to enhance our understanding of self-gift giving behavior. Self-regulatory theory isused as a conceptual support to achieve this objective. The main idea that is explored is that consumers’ self-gift purchase intentions vary acrosscontexts and situations to the extent that these are compatible or not with their self-regulatory mindset, whether it is chronic or situational.Design/methodology/approach – Two studies, using a scenario-based experiment, were conducted to investigate the effects that regulatory focushas on consumers’ intentions to buy themselves a gift.Findings – The results support the proposition that the chronic form of regulatory focus in success and failure situations has a significant impacton the intention to purchase a gift to oneself and show that the situational form of regulatory focus has an influence on self-gift purchase intentionas well. They also confirm that situations that are congruent with consumers’ self-regulatory mindset lead to stronger self-gift purchase intentions.Originality/value – The main contribution of this research lies in delineating the role that some specific dispositional and situational factors playin shaping consumers’ perceptions of success and failure events and how this impacts the eventual purchase of a gift to oneself. This contrasts withprevious research on self-gift giving, where success and failure situations are assumed to be perceived similarly by consumers. Marketing managerswishing to stimulate consumers’ propensity to buy themselves gifts should consider using regulatory focus as a segmentation basis. Marketingcommunications should be adapted to consumers’ self-regulatory mindset.nonouirechercheInternationa
Contributions des méthodes lexicographiques à l’analyse de la construction sociale de l’innovation. Le cas des discours de la presse sur l’EPR
No full textDans cet article, nous nous intéressons à la façon dont est construit socialement, notamment par le prisme de la presse, le caractère innovant (ou non) d’un objet technique particulier : les réacteurs de type EPR (European Pressurized Reactor), labellisés par les acteurs de l’industrie nucléaire depuis le début des années 2000 comme de « 3ème génération ». Nous enquêtons sur cette question en développant une approche lexicométrique à partir d’un corpus de plus de 6 000 articles. Nous proposons une contribution théorique sur la construction sociale de l’innovation et une contribution méthodologique sur les apports d’une méthode lexicométrique.nonouirechercheNationa
Méthodes numériques pour le transport optimal multi-marges
No full textDans cette thèse, notre but est de donner un cadre numérique général pour approcher les solutions des problèmes du transport optimal (TO). L’idée générale est d’introduire une régularisation entropique du problème initial. Le problème régularisé correspond à minimiser une entropie relative par rapport à une mesure de référence donnée. En effet, cela équivaut à trouver la projection d’un couplage par rapport à la divergence de Kullback-Leibler. Cela nous permet d’utiliser l’algorithme de Bregman/Dykstra et de résoudre plusieurs problèmes variationnels liés au TO. Nous nous intéressons particulièrement à la résolution des problèmes du transport optimal multi-marges (TOMM) qui apparaissent dans le cadre de la dynamique des fluides (équations d’Euler incompressible à la Brenier) et de la physique quantique (la théorie de fonctionnelle de la densité ). Dans ces cas, nous montrons que la régularisation entropique joue un rôle plus important que de la simple stabilisation numérique. De plus, nous donnons des résultats concernant l’existence des transports optimaux (par exemple des transports fractals) pour le problème TOMM.In this thesis we aim at giving a general numerical framework to approximate solutions to optimal transport (OT) problems. The general idea is to introduce an entropic regularization of the initialproblems. The regularized problem corresponds to the minimization of a relative entropy with respect a given reference measure. Indeed, this is equivalent to find the projection of the joint coupling with respect the Kullback-Leibler divergence. This allows us to make use the Bregman/Dykstra’s algorithm and solve several variational problems related to OT. We are especially interested in solving multi-marginal optimal transport problems (MMOT) arising in Physics such as in Fluid Dynamics (e.g. incompressible Euler equations à la Brenier) and in Quantum Physics (e.g. Density Functional Theory). In these cases we show that the entropic regularization plays a more important role than a simple numerical stabilization. Moreover, we also give some important results concerning existence and characterization of optimal transport maps (e.g. fractal maps) for MMOT
Complexité des problèmes de satisfaction de contraintes booléennes
No full textouinonouirechercheInternationa
Conditional Importance Networks: A Graphical Language for Representing Ordinal, Monotonic Preferences over Sets of Goods
No full textWhile there are several languages for representingcombinatorial preferences over sets of alternatives,none of these are well-suited to the representationof ordinal preferences over sets of goods (which aretypically required to be monotonic). We proposesuch a language, taking inspiration from previouswork on graphical languages for preference representation, specifically CP-nets, and introduce conditional importance networks (CI-nets). A CI-netincludes statements of the form “if I have a set Aof goods, and I do not have any of the goods fromsome other set B, then I prefer the set of goods Cover the set of goods D.” We investigate expressivity and complexity issues for CI-nets. Then weshow that CI-nets are well-suited to the descriptionof fair division problems.ouinonouirechercheInternationa