Improving the Asymmetric TSP by Considering Graph Structure

Recent works on cost based relaxations have improved Constraint Programming (CP) models for the Traveling Salesman Problem (TSP). We provide a short survey over solving asymmetric TSP with CP. Then, we suggest new implied propagators based on general graph properties. We experimentally show that such implied propagators bring robustness to pathological instances and highlight the fact that graph structure can significantly improve search heuristics behavior. Finally, we show that our approach outperforms current state of the art results.Comment: Technical repor

Systemic design of multidisciplinary electrical energy devices: a pedagogical approach

In this paper, we present a complete educative project for illustrating the design and the analysis of hybrid electrical systems. It is based on the study of an ElectroHydrostatic Actuator for flight control application, fed by a power supply associating a PEM fuel cell with a ultracapacitor storage. This system is controlled to achieve a typical energy management strategy of this multi source structure. Step by step, student can faces typical issues relative to the design of heterogenous and multidisciplinary devices by achieving eight pedagogical objectives. These eight targets are focused on methodological approach for multi domain modelling (Bond Graphs), causal analysis, but also on simulation of complex heterogeneous systems. A typical hybrid system feeding an ElectroHydrostatic Actuator (EHA) for flight control application has to be designed which drives students towards other pedagogical objectives: system based device sizing (fuel cell and ultracapacitor), energy management, system analysis

Asymptotic Properties of Optimal Trajectories in Dynamic Programming

We prove in a dynamic programming framework that uniform convergence of the finite horizon values implies that asymptotically the average accumulated payoff is constant on optimal trajectories. We analyze and discuss several possible extensions to two-person games.Comment: 9 page

Dynamical evolution of the Gliese 436 planetary system - Kozai migration as a potential source for Gliese 436b's eccentricity

The close-in planet orbiting GJ 436 presents a puzzling orbital eccentricity considering its very short orbital period. Given the age of the system, this planet should have been tidally circularized a long time ago. Many attempts to explain this were proposed in recent years, either involving abnormally weak tides, or the perturbing action of a distant companion. We address here the latter issue based on Kozai migration. We propose that GJ 436b was formerly located further away from the star and that it underwent a migration induced by a massive, inclined perturber via Kozai mechanism. In this context, the perturbations by the companion trigger high amplitude variations to GJ 436b that cause tides to act at periastron. Then the orbit tidally shrinks to reach its present day location. We numerically integrate the 3-body system including tides and General Relativity correction. We first show that starting from the present-day location of GJ 436b inevitably leads to damping the Kozai oscillations and to rapidly circularizing the planet. Conversely, starting from 5-10 times further away allows the onset of Kozai cycles. The tides act in peak eccentricity phases and reduce the semi-major axis of the planet. The net result is an evolution characterized by two phases: a first one with Kozai cycles and a slowly shrinking semi-major axis, and a second one once the planet gets out of the Kozai resonance characterized by a more rapid decrease. The timescale of this process appears in most cases much longer than the standard circularization time of the planet by a factor larger than 50. This model can provide a solution to the eccentricity paradox of GJ 436b. Depending on the various orbital configurations, it can take several Gyrs to GJ 436b to achieve a full orbital decrease and circularization. According to this scenario, we could be witnessing today the second phase of the scenario where the semi-major axis is already reduced while the eccentricity is still significant. We then explore the parameter space and derive in which conditions this model can be realistic given the age of the system. This yields constraints on the characteristics of the putative companion.Comment: 13 pages To appear in Astronomy \& Astrophysic

A dynamic gradient approach to Pareto optimization with nonsmooth convex objective functions

In a general Hilbert framework, we consider continuous gradient-like dynamical systems for constrained multiobjective optimization involving non-smooth convex objective functions. Our approach is in the line of a previous work where was considered the case of convex di erentiable objective functions. Based on the Yosida regularization of the subdi erential operators involved in the system, we obtain the existence of strong global trajectories. We prove a descent property for each objective function, and the convergence of trajectories to weak Pareto minima. This approach provides a dynamical endogenous weighting of the objective functions. Applications are given to cooperative games, inverse problems, and numerical multiobjective optimization

Side-slipping of a radiating particle

Radiation reaction is revisited, first in a new classical aproach, where the physical particle 4-momentum is redefined as the energy-momentum flux across the future light cone and is not parallel to the 4-velocity. Then in a semi-classical approach, it is shown that, when emitting a photon, the particle "side-slips" transversaly to its initial momentum, justifying the non-colinearity between momentum and mean velocity. Side-slipping is finally checked in a pure quantum mechanical treatment of synchrotron radiation.Comment: 8 pages, 6 figures. presented at the Int. Conf. QEDSP 2001, dedicated to the 90th anniversary of A.I.Akhiezer, Kharkov (Ukraine) Oct. 30 - Nov. 3, 2001 To appear in the proceeding

Homogenization approach to the behavior of suspensions of noncolloidal particles in yield stress fluids

The behavior of suspensions of rigid particles in a non-Newtonian fluid is studied in the framework of a nonlinear homogenization method. Estimates for the overall properties of the composite material are obtained. In the case of a Herschel-Bulkley suspending fluid, it is shown that the properties of a suspension with overall isotropy can be satisfactory modeled as that of a Herschel-Bulkley fluid with an exponent equal to that of the suspending fluid. Estimates for the yield stress and the consistency at large strain rate levels are proposed. These estimates compare well to both experimental data obtained by Mahaut et al [J. Rheol. 52, 287-313 (2008)] and to experimental data found in the literature

Foreign policy and the politics of alterity: A dialogical understanding of International Relations

Tratando específicamente de no caer ni en el eclecticismo ni en la redundancia, este artículo tiene por objetivo desarrollar una perspectiva dialógica de las Relaciones Internacionales en el ámbito metateórico del constructivismo. La idea de dialogismo sostiene que el mundo social se construye por medio del entrelazamiento de discursos entre varios interlocutores que se responden los unos a los otros. Del mismo modo, proporciona una herramienta interpretativa, el enfoque hermenéutico, que permite concebir la identidad de los interlocutores como un factor en las RRII por medio de la diferenciación entre su expresividad, la contextualidad y la relacionabilidad. El presente artículo, que aborda más detenidamente los conceptos de la identidad y la formación de la identidad en la disciplina de las RRII, comprende la identidad nacional como un aspecto que se refleja en un factor concreto de la política exterior: la política de alteridad. Basando mi enfoque en las obras del intelectual ruso Mijaíl Mijáilovich Bajtín, en la primera parte del artículo defino cómo hemos de entender el dialogismo y su noción constitutiva de la exterioridad. La segunda parte está dedicada a la integración de facto del concepto del dialogismo en la disciplina de las RRII. Un ejemplo tomado de la política interior y exterior japonesa anterior a la Segunda Guerra Mundial nos facilita además la comprensión del argumento teórico sobre la relación entre lo nacional y lo internacional en una política de alteridadTrying specifically not to fall into either eclecticism or redundancy, this paper is an attempt to develop a dialogical understanding of international relations within the meta-theoretical field of constructivism. Dialogism holds that the social world is constructed through an interweaving of mutually-responsive discourses between several agents. Further, it provides an interpretative tool, the hermeneutical locus, to understand agents’ identities as a factor in international relations by discerning their expressivity, contextuality and relationality. Dealing more closely with the questions of identity and identity formation within the discipline of International Relations, the paper further regards national identity as a factor which is expressed in a particular aspect of foreign policy: the politics of alterity. Grounding my approach in the works of the Russian intellectual Mikhail Mikhailovitch Bakhtin, in the first part of the paper I define what is to be understood by dialogism and its constitutive notion of transgredience. The second part is dedicated to the actual integration of dialogism within the discipline of International Relations. An example drawn from Japanese domestic and foreign policy prior to the Second World War further facilitates the comprehension of the theoretical argument concerning the link between the national and the international in a politics of alterit