Parcours paralleles de graphes d'etats par des algorithmes de la famille de A* en intelligence artificielle

Projet PARADISDe nombreux algorithmes paralleles pour les parcours de graphes d'etats de la famille de A* en intelligence artificielle, implantes sur des machines allant du type SIMD massivement parallele au reseau de stations de travail en passant par le MIMD a memoire partagee, ont ete proposes cette derniere decennie. Ces algorithmes sont analyses et classifies suivant le type de parallelisme et l'architecture des machines paralleles utilisees. Nous avons degage et repertorie les principales techniques de parallelisation des parcours de graphes d'etats en intelligence artificielle et en recherche operationnelle, ainsi que leurs modes de programmation

Parcours parallele d'arbres Minimax

Projet PARADISRésumé disponible dans le fichier PD

Strategic and Tactical Urban Farm Design

International audienceWe use mix integer linear programing to establish a model for fresh fruit and vegetable production. We aim at maximizing the annual farm result, responding to a fixed daily demand. Our main variables are the area to grow using specific management practices, the beginning date of each plot cultivation and the workers to hire to produce. We introduce variables to consider the perishability of the products in different ways. As Ahumada and Villalobos (2009), we use a storage cold room loss function and cold room limited capacity. But we also allow a standing storage on the plot, associated to another loss function: the crops can be harvested some days after the ideal harvest time. The selling price is lowered according to storage time, both on the plot and in the cold room. We force the unsold products left on the plots (losses) to be harvested before a management practice dependent deadline, to limit diseases and insects proliferation. Considering short time perishability (a few days) make us work on a tow-day step. It enables a good combination of different crop management practices on the farm to have the best labor affectation. Perishability, considered at a tactical level, has major consequences on the strategic farming system sizing

Contributions à la chaine logistique numérique (conception de circuits courts et planification décentralisée.)

Le concept de chaîne logistique numérique regroupe l'ensemble des modèles, méthodes et outils qui permettent de planifier les décisions sur des prototypes numériques de chaîne logistique. Dans ce travail de thèse, nous proposons deux contributions à la chaîne logistique numérique. Nos résultats se destinent en particulier aux réseaux de Petites et Moyennes Entreprises/Industries. D'une part, nous étudions deux nouveaux problèmes liés à la conception de réseaux logistiques en circuits courts et de proximité pour les produits agricoles frais. Pour chacun d'eux nous proposons une formulation en Programme Linéaire à Variables Mixtes. De plus des méthodes de résolution fondées sur des décompositions du modèle nous permettent de résoudre des instances de grande taille. Pour chaque problème, cette approche est mise en œuvre sur une étude de cas menée avec plusieurs collectivités territoriales. D'autre part, nous étudions le problème de planification tactique des activités de production, de transport et de stockage. Contrairement aux approches classiques centralisées, nous considérons que les décisions des différents acteurs sont prises de manière décentralisée. Nous étudions la manière de décomposer les décisions entre les acteurs ainsi que leurs comportements individuels. Nous analysons aussi des protocoles de concertation basés sur un échange limité d'informations. Afin de répondre à la double complexité du problème, nous proposons un outil innovant qui couple une simulation à base de multi-agents à des approches d'optimisation par programmation mathématique.The concept of digital supply chain gathers models, methods and tools to plan decisions on digital prototypes of supply chains. This doctoral dissertation proposes two contributions to digital supply chain. Mainly, our results address small and medium enterprises/industries. Firstly, we study two new problems related to service network design for short and local fresh food supply chains. For each of them we propose a Mixed Integer Linear Programming formulation. Decomposition-based methods are implemented in order to solve large scale instances. For each problem this approach is applied on a case study conducted with several local institutions. Secondly, we address the tactical supply chain planning problem: how to plan production, transportation and storage activities. As opposed to the classic centralized version, the decision making process is considered decentralized. We study how to decompose the decisions between actors as well as their individual behaviour. We also analyze negotiation processes based on limited information sharing. In order to address the double complexity of the problem, we propose an innovative tool coupling a multi-agent based simulation approach with optimization approaches based on mathematical programming.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

A Suitable data structure for parallel A

Projet PARADI

An efficient two-phase iterative heuristic for Collection-Disassembly problem

Closing the loop in the supply chains is one of the mandatory conditions for more sustainable development. The Collection-Disassembly Problem appears in the reverse part of the closed-loop supply chains. Its aim is to coordinate the activities of collection of end-of-life products from collection centres and their subsequent disassembly. The disassembly step is required for efficient remanufacturing and recycling of returned products. The Collection-Disassembly problem integrates such optimization problems as dynamic lot-sizing and vehicle routing in general cases. In this paper, we develop a Two-Phase Iterative Heuristic to efficiently address large size instances. The numerical tests show that the heuristic provides good solutions under acceptable computational time

Coordination of Collection and Disassembly Planning for End-of-Life Product

This work proposes a formulation for coordinating between collection and disassembly planning for an End-of-Life (EOL) product. The coordination deals with the balance between the number of products collected, the inventory level and the number of products disassembled. The objective function aims to minimize the total cost including the disassembly cost, the penalty cost, the holding cost and the running cost of vehicle. Two strategies with and without coordination were compared via numerical experiments. The results obtained show that the coordinated strategy allows total cost reducing

Collection-disassembly problem in reverse supply chain

The reverse supply chain and disassembly processes are getting more and more important for tackling the burden of waste electrical and electronic equipment. The disassembly's complexity and frequent manual operation makes this process relatively expensive compared to its potential profit. The collection of end-of-life product is also a big issue dealing with vehicle routing. Thus, the decisions taken for collection and disassembly of end-of-life products need to be optimised. In this work, an optimisation model is developed for incorporating these problems. Our experimental study shows joint optimisation of collection and disassembly with coordination between them improves the global performance of the reverse supply chain including lower total cost corresponding to the component demand satisfaction

Clinical Characteristics and Histopathology of Idiopathic Epiretinal Membrane in Vietnam

BACKGROUND: Idiopathic epiretinal membrane (iERM) is an avascular proliferation of different types of cells between the posterior vitreous cortex and the internal limiting membrane. That causes visual impairment including blurry, distortion, scotoma. Many studies of iERM were done to describe the clinical characteristics and investigate the histopathology of this disease. Nonetheless, there has not been a study of iERM histopathology in Vietnam. AIMS: To describe clinical characteristics and histopathological results of idiopathic retinal membrane and the association between them. METHODS: A cross sectional decriptive study of 35 iERMs (33 patients) in Vietnam National Institute of Ophthalmology (VNIO). RESULTS: High morbidity incidence was in group age >50 years (32/35), female gender (26/35), limited movement works (27/35), and high educational levels (28/35). Distortion was the highest (77.14%), scotoma and floater was less frequent (28.5%, 45.7%). Macular edema in all cases and PVD and exudate were high frequent (65.7%, 62.8%). Symptom duration was 8.2 ± 4.7 months, (1-21 months). Mean of central macular thickness was 468.51 ± 97.24 µm (656-274 µm). Six types of cell were detected, including glial cell (35/35), fibroblast (23/35), myofibroblast (23/35), macrophage (13/35), lymphocyte (5/35) and neutrophil (2/35). The number of cell types in one sample ranged from 1-5 types (2.85 ± 1.28 cell types). Number of cell types were correlated to symptom duration (r = 0.47, p = 0.004, Pearson's test) and central macular thickness (r = 0.72, p < 0.001, Pearson's test). CONCLUSION: There were 6 types of cells in iERM. Glial cell was the most frequent cell, inflammatory cells (macrophage, lymphocyte, neutrophil) was also detected. The number of cell types was stastitically correlated to symptom duration and CMT

Adaptive and Hybrid Algorithms: classification and illustration on triangular system solving

International audienceWe propose in this article a classification of the different notions of hybridization and a generic framework for the automatic hybridization of algorithms. Then, we detail the results of this generic framework on the example of the parallel solution of multiple linear systems