Letteratura scientifica selezionata sul tema "Optimisation du routage"
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Articoli di riviste sul tema "Optimisation du routage"
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Sasse, Jana, Malte Schön e Christian Hopmann. "Static Mixers Producible by Additive Manufacturing: Novel Rapid Automatic Optimisation and Practical Evaluation". Polymers 14, n. 21 (1 novembre 2022): 4646. http://dx.doi.org/10.3390/polym14214646.
Testo completoAbstract (sommario):
In the extrusion of plastics, the thermal and material homogeneity of the plastic melt at the die entry are of high importance for the extrudate quality. While static mixers are widely used to improve the melt homogeneity, previous attempts at optimisation for reduced pressure loss and improved mixing had to be performed by hand and human experience, limiting the degrees of freedom and efficiency. A new automatic optimisation method based on the open source software OpenFOAM was developed. Using immersed boundary methods, new target functions in the pre-existing routine adjointShapeOptimizationFoam and an additional algorithm checking the suitability for additive manufacturing and fixing the geometry during run-time is presented. The new algorithm is used to optimise an existing static mixer based on an X-type geometry with integrated oil channels, maximising the heat exchange between oil and melt. Based on the results of these simulative optimisations, the best candidates were manufactured using selective laser melting and experimental trials were run. Experimental validation shows that with our optimisation algorithm, a pressure loss reduction of 10% could be achieved. The core melt temperature was reduced by 6 ∘C, improving the thermal homogenisation as well. While the main advantage of this method is the rapid optimisation taking the operating point into account, the trials also showed positive results in off-design operating points. This allows the low-cost design and manufacture of individualised static mixers.
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Şugar Gabor, O., A. Koreanschi e R. M. Botez. "Analysis of UAS-S4 Éhecatl aerodynamic performance improvement using several configurations of a morphing wing technology". Aeronautical Journal 120, n. 1231 (7 giugno 2016): 1337–64. http://dx.doi.org/10.1017/aer.2016.61.
Testo completoAbstract (sommario):
ABSTRACTThe paper presents the results of the aerodynamic optimisation of an Unmanned Aerial System's wing using a morphing approach. The shape deformation of the wing is achieved by placing actuator lines at several positions along its span. For each flight condition, the optimal displacements are found by using a combination of the new Artificial Bee Colony algorithm and a classical gradient-based search routine. The wing aerodynamic characteristics are calculated with an efficient nonlinear lifting line method coupled with a two-dimensional viscous flow solver. The optimisations are performed at angles of attack below the maximum lift angle, with the aim of improving the Hydra Technologies UAS-S4 wing lift-to-drag ratio. Several configurations of the morphing wing are proposed, each with a different number of actuation lines, and the improvements obtained by these configurations are analysed and compared.
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Yang, Z., D. G. Crosby e A. K. Khurana. "MULTIVARIATE OPTIMISATION OF HYDRAULIC FRACTURE DESIGN". APPEA Journal 36, n. 1 (1996): 516. http://dx.doi.org/10.1071/aj95029.
Testo completoAbstract (sommario):
This paper presents a detailed description of a true multivariate optimisation routine for the design of hydraulic fractures. Using the Sequential Unconstrained Minimisation Technique, the optimisation routine intelligently searches for the optimum combination of operator-controllable hydraulic fracture treatment parameters, as opposed to existing simple iterative schemes. Net Present Value (NPV) was used as a measure of the economic impact of hydraulic fracture design on incremental reservoir production revenue. The effects of individual treatment parameters on incremental NPV were investigated for a hypothetical well. The results showed that there was an optimum value for each of the treatment parameters: injection period, injection rate and proppant concentration. For the same hypothetical well, contours of incremental NPV vs two fracture treatment parameters (injection period/injection rate and injection period/proppant concentration) were also constructed. These contours were smooth and continuous and did not show multiple extreme value points. These observations imply that there should be no obvious barriers to the estimation of the optimal hydraulic fracture design using the optimisation routine. Indeed, through visual inspection of the contours in the case of 2 treatment parameters, the optimisation routine consistently arrived at the optimum solution for a given set of inputs. The optimisation routine was extended to 3 treatment parameters (injection period, rate, and proppant concentration) and again consistently arrived at the same optimum solution with different starting positions. The optimisation routine can be extended to any number of operator controllable treatment parameters.
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Read, Nathaniel, e Eugene Shwageraus. "APPLICATION OF TWO STAGE METHOD OF CHARACTERISTICS / SP3 METHODOLOGY TO TRISO-FUELLED LEU SPACE REACTOR IN WIMS 11". EPJ Web of Conferences 247 (2021): 01009. http://dx.doi.org/10.1051/epjconf/202124701009.
Testo completoAbstract (sommario):
In order to minimise the mass of a 1MWe LEU space fission power system design, a rapid neutronics analysis tool is sought. A two-stage deterministic analysis routine has been constructed using a core-plane method of characteristics calculation followed by a full-core SP3 calculation, within the ANSWERS© code WIMS11. This is compared to a faster route that skips the core-plane calculation and also the Monte Carlo code Serpent. Results suggest sufficiently good agreement for the WIMS-based methods to be useful in a full system mass-minimising optimisation routine.
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Ramtake, Dhammpal, Sanjay Kumar e V. K. Patle. "Route Optimisation byAnt Colony OptimisationTechnique". Procedia Computer Science 92 (2016): 48–55. http://dx.doi.org/10.1016/j.procs.2016.07.322.
Testo completo
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Mezitis, Mareks, Arpabekov Muratbek, Zura Sansyzbayeva e Alimzhan Assiltayev. "Enhancing effectiveness of use of the rolling stock through route optimisation". AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 19, n. 12 (31 dicembre 2018): 808–10. http://dx.doi.org/10.24136/atest.2018.502.
Testo completoAbstract (sommario):
The article deals with issues of enhancing efficient use of the rolling stock of urban passenger transport through route optimisation. The authors offer to upgrade urban route network opt for: optimisation of routing system. In order to streamline passenger transport performance, the authors propose to calculate transport route schemes by applying economically mathematical methods of planning.
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Li, Jialu. "Research on Route Optimization of RO-Ro Ship Based on Ant Colony Algorithm". Applied and Computational Engineering 110, n. 1 (6 dicembre 2024): 201–11. https://doi.org/10.54254/2755-2721/2024.melb18117.
Testo completoAbstract (sommario):
This study is based on an ant colony algorithm for route optimisation of roll-on roll-off (RO-RO) vessels, aiming to minimise the total cost of RO-RO shipping routes. The model takes into account factors such as port berthing cost, fuel consumption and sailing time, and ensures the stability and efficiency of the optimisation results by adjusting the algorithm parameters such as pheromone initialisation, pheromone evaporation rate and ant colony size. The results of the study provide a practical solution for ro-ro ship route optimisation, which significantly reduces the operating costs and also provides key technical support for shipping companies to compete in the global market. In addition, the study demonstrates the potential of the optimisation model to reduce transport costs, improve shipping efficiency and reduce carbon emissions, providing an effective technical support for shipping companies in an increasingly competitive global market. Through this optimisation approach, shipping companies are able to better manage their route selection, resource allocation and operational processes, enhancing market competitiveness and promoting sustainable development of the shipping industry.
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Lombardi, G., e A. Vicini. "Induced drag prediction for wing-tail and canard configurations through numerical optimisation". Aeronautical Journal 98, n. 976 (luglio 1994): 199–206. http://dx.doi.org/10.1017/s0001924000049733.
Testo completoAbstract (sommario):
Abstract A computational procedure has been developed in order to predict aerodynamic interference between lifting surfaces, and to devise configurations which best meet given aerodynamic requirements. The procedure, which couples an aerodynamic solver with a numerical optimisation routine, is useful in the preliminary design of aircraft. The essential features of the aerodynamic code and of the optimisation routine are described, along with the coupling criteria. Some of the most significant predictions obtained in induced-drag minimisation for wing-tail and canard configurations are described and discussed.
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John, Jacob, e S. Sakthivel. "Brain Storm Water Optimisation-Driven Secure Multicast Routing and Route Maintenance in IoT". Journal of Information & Knowledge Management 20, Supp01 (febbraio 2021): 2140010. http://dx.doi.org/10.1142/s0219649221400104.
Testo completoAbstract (sommario):
In several Internet of Things (IoT) applications, messages are disseminated to some objects or nodes based on multicast transmissions. However, previous multicast routing schemes in IoT focussed mainly on the ad-hoc sensor network, but they are not robust and responsive in the IoT environment. Hence, this paper introduces the multicast routing protocol based on the proposed optimisation algorithm, named Brain Storm Water Optimisation (BSWO), in the IoT network. By the multicast routing protocol, the multicast path is designed from a multicast source node to various destinations. The multicast source node forwards packet to multiple destinations simultaneously. Initially, the nodes in the IoT network are simulated together and perform the multicast routing process effectively using the proposed optimisation framework. The multicast routing protocol performs the multicast routing mechanism using the multiobjective factors, such as distance, delay, energy, link-quality factor and trust. The multicast routing path is effectively chosen based on the developed BSWO through fitness measures. The proposed BSWO is designed by integrating the Brain Storm Optimisation (BSO) and Water Wave Optimisation (WWO), respectively. The path with the minimum distance is selected as an optimal path using the fitness parameters like delay, distance, trust, energy and link-quality factor. The proposed optimisation algorithm effectively performs the multicast routing mechanism by integrating the parametric features from both the optimisation algorithms. Once the multicast routing mechanism is done, the route maintenance process is carried out in the simulated IoT network to recover the link breakage. The proposed BSWO outperformed other methods with the minimal delay of 0.0682[Formula: see text]s, minimal average routing distance of 178.4[Formula: see text]m, maximal energy of 39.59[Formula: see text]J, maximal throughput of 87.75% and maximal trust of 90%, respectively.
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Shahpar, S. "Challenges to overcome for routine usage of automatic optimisation in the propulsion industry". Aeronautical Journal 115, n. 1172 (ottobre 2011): 615–25. http://dx.doi.org/10.1017/s0001924000006308.
Testo completoAbstract (sommario):
Abstract In industry, there is an ever-increasing requirement not only to design high performance new products but also to deliver them at lower cost and in shorter time. To meet these demanding engineering challenges, it is not sufficient to treat the different disciplines involved in a product design in isolation; rather they must be considered together as an integrated system that reflects the dependencies and interactions of the different disciplines. The design process must be automated to meet the stringent design time-lines. In spite of promising forays for over a decade, automatic design optimisation (ADO) and multidisciplinary optimisation (MDO) has not been widely adapted by the Turbomachinery design practitioners. This presentation will explore some of the technical and nontechnical barriers such as cultural and organisational issues that must be addressed if ADO/MDO is to be used routinely in industry. Some recent, successful application of automatic optimisation is also reported herein.
Tesi sul tema "Optimisation du routage"
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De, oliveira Thomas. "Optimisation du routage d'un filtre CEM". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00739424.
Testo completoAbstract (sommario):
La tendance de l'intégration en électronique de puissance accentue naturellement les effets électromagnétiques parasites. Tout système d'énergie électrique devient alors source de perturbations EM aussi bien conduites que rayonnées. Mais dans le cadre de ces travaux, nous nous sommes focalisé sur l'organe de filtrage des perturbations conduites : le filtre CEM. En haute fréquence, il s'avère que ce type de système voit son comportement dégradé en raison des différents phénomènes parasites apparaissant au sein même du dispositif. Seuls les aspects magnétiques du problème ont néanmoins été traités (i.e. inductances partielles & couplages magnétiques parasites). Différentes méthodes ont été mises au point par le passé dans le but d'améliorer facilement la réponse du filtre. Cependant, il s'agit de procédés empiriques ne pouvant garantir l'optimalité de la solution de filtre construite. Les travaux réalisés au cours de cette thèse ont donc consisté à développer une nouvelle méthode d'optimisation d'un filtre CEM, et plus précisément de son routage. L'objectif est alors d'exploiter les différents phénomènes magnétiques parasites intrinsèques au montage. Calculer ce type d'éléments a donc nécessité l'utilisation d'un outil de modélisation PEEC ; méthode numérique permettant des calculs rapides en raison d'un maillage relativement limité.
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Oliveira, Thomas de. "Optimisation du routage d'un filtre CEM". Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT082/document.
Testo completoAbstract (sommario):
La tendance de l'intégration en électronique de puissance accentue naturellement les effets électromagnétiques parasites. Tout système d'énergie électrique devient alors source de perturbations EM aussi bien conduites que rayonnées. Mais dans le cadre de ces travaux, nous nous sommes focalisé sur l'organe de filtrage des perturbations conduites : le filtre CEM. En haute fréquence, il s'avère que ce type de système voit son comportement dégradé en raison des différents phénomènes parasites apparaissant au sein même du dispositif. Seuls les aspects magnétiques du problème ont néanmoins été traités (i.e. inductances partielles & couplages magnétiques parasites). Différentes méthodes ont été mises au point par le passé dans le but d'améliorer facilement la réponse du filtre. Cependant, il s'agit de procédés empiriques ne pouvant garantir l'optimalité de la solution de filtre construite. Les travaux réalisés au cours de cette thèse ont donc consisté à développer une nouvelle méthode d'optimisation d'un filtre CEM, et plus précisément de son routage. L'objectif est alors d'exploiter les différents phénomènes magnétiques parasites intrinsèques au montage. Calculer ce type d'éléments a donc nécessité l'utilisation d'un outil de modélisation PEEC ; méthode numérique permettant des calculs rapides en raison d'un maillage relativement limitéThe actual trend to integrate the power electronic devices naturally increases the stray electromagnetic phenomena. Every electrical system becomes thus an EM disturbances source. But as part of this work, we especially focused on the filtering device of conducted disturbances : the EMC filter. For high frequencies, degradations can be observed over the filter transfer function due to the different stray electromagnetic phenomena occurring within the device. But only the magnetic aspects have nevertheless been treated (i.e. partial inductances & stray magnetic couplings). Different methods have been worked out in the past in order to easily improve the filter response. However, these are empirical processes that could not guaranty the built filter solution optimality. The works done throughout this PhD have consisted in developing a novel EMC filter optimization method, and more precisely of its routing. The aim has been to use the different stray magnetic phenomena. All of these elements can only be obtained by using a PEEC modeling tool. The PEEC method allows having fast numerical calculations thanks to a quite light meshing
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Rombaut, Matthieu. "Optimisation des réseaux, routage et dimensionnement". Versailles-St Quentin en Yvelines, 2003. http://www.theses.fr/2003VERS0015.
Testo completoAbstract (sommario):
The study presented in this document proposes an industrial approach of the problem of network routing on constrained capacity. Many mathematics studies were done to define methods to design optimal backbone network, or the optimal routing plan on uncapacitated network. Those methods solve linear program or integer program. Some approximation or relaxation must be done to solve most of actual problems. Moreover, the proposed routing plans are in most of the case mono routing plan. Using shortest path algorithms make flows to use a single path, they do not allow the use of subsidiary links taht could be under utilized. We propose in this work routing methods on links of constrained capacities, the Mille Feuilles, and some evolution of the Mille Feuilles algorithm that permit limiting the number of paths. Those methods can be applied for the backbone network conception, and can be defined with several cost functions. Those methods are very close to optimal routing defined with projected gradient without limitation of the number of paths. Used with a non cumulative cost function on the path, they allow decreasing the maximal link load ratio, and increasing the network reliability to flow uncertainties and to single link failure. Moreover, we evaluate performances of several re-routing methods in case of single link failure depending of the rerouting policy applied. The link load variation and the average path lengths variation are bound depending on the re-routing. The routing and re-routing methods are not similar and a routing method adapts itself differently depending on the re-routing method. A new rerouting method is also proposed, that can be applied for any multi-routing planCette étude propose une approche industrielle du problème de routage de données sur des réseaux aux capacités contraintes. Un certain nombre d'études mathématiques ont été réalisées pour définir des plans de routage, par résolution de problèmes linéaires ou en nombres entiers. On constate alors que des approximations doivent être faites pour appliquer les méthodes mathématiques aux problèmes réels. D'autre part, les routages proposés sont pour la plupart simples (mono-routage). L'utilisation des algorithmes de plus courts chemins contraint souvent les flux sur une route unique, ils ne permettent généralement pas l'utilisation de liens annexes dont la charge est faible. Nous proposons des méthodes de routage de flux sur des liens de capacités finies, le routage Mille Feuilles, et des variantes de ce routage permettant de limiter le nombre de routes. Ces méthodes sont applicables au niveau de la conception ou de l'exploitation des réseaux. Ces méthodes d'optimisation par projections successives permettent de mettre en œuvre différentes fonctions coût, elles permettent d'approcher des solutions optimales obtenues à l'aide de méthode de gradient projeté. Associée à une métrique non cumulative sur la route, elles permettent de calculer des plans de routage multi-routes, de diminuer le taux charge du lien le plus chargé sur le réseau 'augmenter la résistance du réseau aux variations de trafic et à l'apparition d'une panne simple. D'autre part, nous évaluons les performances de plusieurs méthodes de re-routage en cas de panne simple d'un lien, en fonction des méthodes de routage appliquées. L'impact des re-routages sur le réseau est évalué, la variation de la charge des liens et la variation de la longueur moyenne des routes sont bornées. Les méthodes de routages ne sont pas équivalentes et elles s'adaptent différemment aux politiques de re-routage proposées. En outre, une nouvelle politique de re-routage applicable aux plans de routage multi-routes est introduite
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WANG, CHENGTIAN. "Routage des navires. Modele de routage de voiliers. Formalisation et optimisation par programmation dynamique". Paris 7, 1990. http://www.theses.fr/1990PA077169.
Testo completoAbstract (sommario):
Notre travail est effectue au sein du scem/previ/mar (prevision marine du service central d'exploitation meteorologique de la meteorologie nationale). Le modele de routage est realise sur calculateur cdc960. Le modele de routage est un modele numerique automatique qui est capable en theorie de trouver une route optimale (une route a temps de parcours minimum precisement) entre le point de depart et le point d'arrivee fixes, a partir des performances du bateau route et des conditions meteo-oceaniques prevues ou climatologiques concernees a l'heure et au point de passage du bateau. Notre modele de routage est fonde sur la theorie des reseaux et la programmation dynamique
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Hijazi, Hassan. "Optimisation non-linéaire mixte en nombres entiers pour la conception de réseaux en télécommunications". Thesis, Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX22107/document.
Testo completoAbstract (sommario):
Dans cette thèse, nous nous basons sur les outils apportés par la programmation mathématique afin de modéliser et résoudre des problèmes relevant du domaine des télécommunications. Notre premier objectif consiste à se conformer aux contraintes réelles, prenant en compte les aléas courants, afin de définir des stratégies optimales de routage et de planification dans les réseaux. Les contributions théoriques concernent l'optimisation convexe non linéaire mixte en nombres entiers. Parmi les résultats majeurs, nous établissons en particulier : *une formulation compacte des contraintes de type "on/off" qui s'écrivent f(x) ≤ 0 si z = 1,I ≤ x ≤ u si z = 0, basée sur une nouvelle caractérisation de l'enveloppe convexe de l'union d'un hyper-rectangle et d'un ensemble convexe dans l'espace des variables d'origine. * Une prise en compte de l'incertitude au niveau des fonctions additives ∑i(fi(xi) + vi) ≤ 0 où vi représente une perturbation bornée de chaque fonction univarée fi(xi). * Un algorithme spécialisé pour les problèmes d'optimisation non-linéaires mixtes en nombres entiers faisant intervenir des fonctions additives. D'un point de vue industriel, ces apports théoriques nous permettent de nous rapprocher de notre objectif consistant à définir des stratégies de gestion optimales pour des réseaux de télécommunications plus fiables. La qualité de service perçue par le client est modélisée par une fonction délai de bout en bout, différentiée selon le type de service et dépendant de la congestion au niveau de chaque lienIn our work, we rely on the powerful arsenal of mathematical programming theory to model telecommunication problems and devise efficient methods for solving them. Our goal is to comply to real life constraints when defining optimal routing strategies and designing efficient capacity planning tools. Theoretical contributions apply the field of Mixed Integer Non-Linear Optimization. Among relevant results, let us mention :Explicit formulations of convex hulls in disjunctive programming, generalizing the famous perspective formulationsTractable compact formulations of problems featuring inerval uncertainty in Robust OptimizationAn efficient Outer-Inner approximation algorithm for solving large families of separable mixed Integer Non-Linear Programs (MINLPs) and Second Order Cone Programs (SOCPs), outperforming state-of-the-art commercial solvers.In the application part, our work aims at introducing reliable telecommunication networks, offering appropriate and guaranteed Quality of Service to all its customers. Today, Wide Access Networks (WAN), Virtual Private Networks (VPN) or IP-based Backbones carry a wide range services, namely: voice, video streaming and data traffic. Each one of these contents has its own performance requirements. Unfortunately, best effort algorithms are implemented at all levels, offering no guarantee for delay sensitive applications. Is it possible to build routing strategies guaranteeing upper bounds on source-to-destination delays? Can we make these routing protocols to delay variation ? Does service differentiation affect capacity planning decisions ? Answers to these questions will be developed in this thesis
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Tusera, Alexandre. "De l'affectation linéaire appliquée au problème de routage dans une grille multidimensionnelle". Versailles-St Quentin en Yvelines, 1995. http://www.theses.fr/1995VERS0004.
Testo completoAbstract (sommario):
Nous nous proposons, dans cette thèse, d'aborder le problème de routage dans une grille par une approche différente des méthodes classiques à la recuit simulé. Nous établissons le rapport entre le problème énoncé et l'affectation linéaire en d dimensions (dD-LAP), problème NP-difficile bien connu de la recherche opérationnelle. Nous étendons l'étude polyédrale du problème 3D-LAP au cas multidimensionnel en montrant l'accroissement de la complexité avec le nombre de dimensions. Parmi les différentes méthodes de résolution de ce problème, nous investiguons en détail les méthodes de sous-gradient, les plus adaptées compte tenu de la taille des problèmes envisagés ; notamment, nous introduisons deux heuristiques nouvelles pour le 3D-LAP: l'approximation locale et l'approximation globale. Toutes les deux sont basées sur la relaxation lagrangienne avec sous-gradient et sur la prise en compte de la structure polyédrale du 3D-LAP pour orienter la direction de recherche le long de la trajectoire du sous-gradient. Le polyèdre du problème est approximé localement/globalement par un nombre restreint de facettes. Donc il s'agit d'une approche encore inconnue dans la littérature, à notre connaissance: comment choisir un ensemble de facettes de cardinalité restreinte contenant des facettes "efficaces" parmi un nombre très grand (typiquement en nombre exponentiel pour un problème NP-difficile
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Zrikem, Maria. "Optimisation du routage de câbles dans les installations de production d'électricité". Paris, CNAM, 2001. http://www.theses.fr/2001CNAM0394.
Testo completoAbstract (sommario):
Lors de la conception du câblage d'une installation de production d'électricité, l'une des étapes consiste à faire cheminer des câbles sur des supports, appelés «tablettes», de capacité limitée. Chaque câble relie un équipement «tenant» à un équipement «aboutissant». L'ensemble des itinéraires choisis doit respecter des contraintes techniques et des contraintes de sécurité imposées par les règles d'installation des câbles. De plus, les coûts engendrés par l'achat et la pose des câbles sont très élevés. Le but est donc de trouver un ensemble d'itinéraires qui minimise le coût total du câblage. D'autre part, le problème du routage de câbles est de grande taille : environ 35000 tablettes et 25000 câbles. Dans une première étape, nous définissons le problème réel et les différentes contraintes à respecter ainsi que les critères à minimiser. Le problème se classe parmi les problèmes de multiflots en entier connus en optimisation combinatoire. Une fois le problème défini, nous décrivons le graphe qui représente les différentes composantes de la centrale nucléaire. Ensuite nous utilisons un formalisme mathématique ensembliste pour modéliser les différentes contraintes et critères. Le problème est de grande taille, ce qui le rend difficile à résoudre. Heureusement, nous le décomposons en plusieurs sous-problèmes de multichemins de longueur totale minimale et sous contraintes de capacité dans des sous-graphes de plus petites tailles. Ces problèmes consistent à relier dans un graphe des paires de sommets données en respectant les contraintes de capacité et en choisissant les chemins de longueur totale minimale. Ces problèmes qui sont un cas particulier des multiflots entiers, sont NP-difficiles : nous dressons un panorama des différentes méthodes présentées dans la littérature qui proposent de bonnes résolutions pour ces problèmes. Nous présentons également trois bornes inférieures proposées pour ce problème. Nous montrons l'équivalence entre la borne obtenue par relaxation Lagrangienne des contraintes de capacité et celle obtenue par une méthode de génération de colonnes. Vu son aspect combinatoire et sa grande taille, nous proposons de résoudre le problème de multichemin de coût minimum sous contraintes de capacité par une nouvelle métaheuristique proposée par Nenad Mladenoviç et Pierre Hansen : Recherche à Voisinage Variable (RVV). Cette heuristique se base sur un changement systématique de voisinage pour éviter les optima locaux. Nous montrons comment nous l'adaptons pour la résolution du problème du câblage. Nous nous intéressons ensuite à une variante de cette heuristique dédiée aux problèmes de grande taille : Recherche et Décomposition à Voisinage Variable. Nous décrivons également son adaptation à notre problème. Les résultats montrent que notre méthode est bien adaptée à ce genre de problèmes. Le problème de multichemins avec longueur totale minimale et sous contraintes de capacité est un problème difficile dans un graphe quelconque. Nous nous intéressons à la résolution exacte de ce problème dans les graphes particuliers que sont les grilles. Nous proposons un algorithme qui résout, de façon exacte, le problème dans une grille où les capacité sont unitaires sur les colonnes et paires sur les lignes. Cet algorithme route chaque liaison sur un plus court chemin. Il est linéaire et d'une complexité qui vaut (n − 1)×d/2, où n est le nombre des liaisons à router et d la densité de la grille. Si la capacité est impaire sur les lignes, nous montrons que le problème de multichemin de longueur totale minimale sous contraintes de capacité n'admet pas toujours une solution des plus courts chemins.
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Bourquia, Nawal. "Optimisation du routage dans les réseaux internet avec qualité de service". Paris 9, 2003. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=2003PA090023.
Testo completoAbstract (sommario):
Dans les réseaux Internet, les protocoles de routage classiques acheminent les demandes de trafic sur des plus courts chemins selon des poids administratifs fixés sur les liens de ces réseaux. Il peut arriver que plusieurs plus-courts chemins existent entre l'origine et la destination d'une demande. Dans ce cas, un chemin parmi les plus courts est arbitrairement choisi, et l'administrateur du réseau n'a plus la maîtrise des chemins de routage, ou alors un partage de charge, difficile à gérer, est réalisé. De plus, une certaine qualité de service est devenue nécessaire à garantir avec l'explosion du trafic Internet. Nous nous sommes donc intéressés au problème de routage selon d'uniques plus-courts-chemins; nous déterminons un ensemble de poids qui assure l'unicité des plus-courts-chemins de routage tout en optimisant un critère de garantie de performance dans le choix de ces chemins. Nous modélisons ce problème par un programme linéaire à variables mixtes et nous le résolvons avec des méthodes de l'optimisation combinatoireIn most Internet routing protocols, traffic demands are routed on shortest paths according to a set of administrative weights. However, several shortest paths can co-exist between the origin and the destination of a demand. In this case, one of these shortest paths is arbitrarily chosen to route the demand or a load balancing is realized, and it becomes difficult for the administrator of the network to control the overall routing paths scheme or to manage the load balancing. Quality of service has also become necessary because of the explosion of Internet traffic these last years. This is the reason why we focused on the problem of unique shortest paths routing for which we determine a set of weights that ensures the unicity of the shortest paths while optimizing a quality of service criterion. We formulate this routing problem using linear programs with mixed integer variables and solve it with combinatorial optimization methods
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CHICH, THIERRY. "Optimisation du routage a deflexion pour les reseaux de telecommunications metropolitains". Lyon, École normale supérieure (sciences), 1997. http://www.theses.fr/1997ENSL0078.
Testo completoAbstract (sommario):
Dans l'avenir, les reseaux metropolitains devront relier differentes ressources informatiques a l'echelle d'une ville. Dans ce cadre, la technologie optique, qui permet l'obtention d'une bande passante de l'ordre de la dizaine de terabits/s, est prometteuse. Cette these a pour objectif de proposer une etude d'un routage particulierement adapte aux reseaux tout-optiques, le routage par deflexion. Nous nous sommes particulierement interesse a la question de la synchronisation dans les reseaux a deflexion. En effet, la tres grande majorite des etudes faites sur le routage par deflexion suppose une synchronisation du reseau. Or, celle-ci impose que les paquets soient de tailles fixes. De plus, les synchronisateurs dans les reseaux tout-optiques sont couteux, dissipateur de puissance, et abaisse la fiabilite du reseau. Nous avons montre que desynchroniser le reseau ne changeait pas fondamentalement son comportement, contrairement a ce qui est souvent affirme, mais seulement son niveau de performance. Qui plus est, nous avons montre que la baisse des performances provenait moins de l'asynchronisme en tant que tel que de l'absence d'optimisation locale sur les preferences des paquets. Une telle optimisation est tout a fait naturelle dans un reseau synchrone. Nous basant sur cette premiere etude, nous avons propose deux methodes de natures tres differentes pour optimiser le routage par deflexion asynchrone. La premiere consiste en un algorithme de routage adaptatif qui permet d'eviter les zones surchargees du reseau lorsque la topologie est une grille ou un tore. Cet algorithme a ete teste sous diverses conditions, et s'est montre efficace pour la deflexion asynchrone. La deuxieme methode est un dispositif permettant d'effectuer une optimisation locale sur les preferences des paquets en mode asynchrone. Ce dispositif donne d'excellents resultats qui semblent etre de nature a remettre radicalement en question la necessite de synchroniser les reseaux a deflexion.
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Prodhon, Caroline. "Le problème de localisation-routage". Troyes, 2006. http://www.theses.fr/2006TROY0010.
Testo completoAbstract (sommario):
Cette thèse porte sur le problème de localisation-routage (Location-Routing Problem – LRP). Il s’agit d’un problème de logistique du transport qui implique deux niveaux de décision : la localisation de dépôts (niveau stratégique) et l’élaboration de tournées de véhicules (niveau tactique ou opérationnel). Ces deux niveaux sont souvent inter-dépendants, mais pour des raisons de simplification, ils sont généralement traités séparément. Or, de récentes recherches ont montré que la prise en compte des futures tournées dans la résolution d’un problème de localisation permettait des gains significatifs sur les coûts totaux. Il existe de nombreuses applications du LRP comme la distribution du courrier, la livraison de colis ou la collecte de déchets. La motivation des travaux développés ici est d’aborder un problème difficile et dans une version encore peu étudiée dans la littérature, comportant des capacités limitées à la fois pour les dépôts à ouvrir et pour les véhicules réalisant les tournées. De plus, des problèmes de taille réaliste sont visés, c’est-à-dire avec un nombre de clients à servir allant jusqu’à 200. Nous proposons des techniques de résolutions prenant en considération l’intégralité du problème, sans décomposition hiérarchique en deux phases, par le biais de méthodes de type heuristique, mais également avec une approche exacte basée sur de nouveaux modèles mathématiques. Tous les algorithmes développés ont été testés et validés sur des jeux d’essais nouveaux ou provenant de la littératureThis thesis concerns the Location-Routing Problem (LRP). This is a transportation problem that combines two levels of decision: depot location (strategic level) and vehicle routing (tactical or operational level). In distribution systems, these levels are often interdependent, but for simplifications, they are generally solved individually. Recent studies have shown that the overall system cost may be reduced if routing decisions are considered when locating depots. There exist various applications for the LRP, like mail distribution, parcel delivery or waste collection. The motivation for the developed studies is to deal with a difficult problem, in a version comprising capacitated depots and capacitated vehicles. Large-scale instances are targeted, i. E. To stay with up to 200 customers to visit. We propose to solve the LRP with techniques that handle the entire problem without hierarchical decomposition in two phases. They consist in heuristic approaches but also in an exact method based on new mathematical formulations. All the proposed algorithms are tested and validated on new instances or on bench-marks from the literature
Libri sul tema "Optimisation du routage"
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Dingzhu, Du, Hwang Frank e DIMACS Workshop on Network Switching (1997 : Princeton University), a cura di. Advances in switching networks: DIMACS workshop, July 7-9, 1997. Providence, RI: American Mathematical Society, 1998.
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Bredin, Linda. Detection of HPV by in-situ hybridisation: Optimisation and introduction into the routine histology laboratory. [S.l: The Author], 2003.
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Rafiq, Saqib. A decision support system for route optimisation analysis and network cost calculations for an airline. Oxford: Oxford Brookes University, 2003.
Cerca il testo completoCapitoli di libri sul tema "Optimisation du routage"
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Paviotti, Marco, Simon Cooksey, Anouk Paradis, Daniel Wright, Scott Owens e Mark Batty. "Modular Relaxed Dependencies in Weak Memory Concurrency". In Programming Languages and Systems, 599–625. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-44914-8_22.
Testo completoAbstract (sommario):
AbstractWe present a denotational semantics for weak memory concurrency that avoids thin-air reads, provides data-race free programs with sequentially consistent semantics (DRF-SC), and supports a compositional refinement relation for validating optimisations. Our semantics identifies false program dependencies that might be removed by compiler optimisation, and leaves in place just the dependencies necessary to rule out thin-air reads. We show that our dependency calculation can be used to rule out thin-air reads in any axiomatic concurrency model, in particular C++. We present a tool that automatically evaluates litmus tests, show that we can augment C++ to fix the thin-air problem, and we prove that our augmentation is compatible with the previously used compilation mappings over key processor architectures. We argue that our dependency calculation offers a practical route to fixing the longstanding problem of thin-air reads in the C++ specification.
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Raghestani, Nikmal, e Carsten Keßler. "Route Optimisation for Winter Maintenance". In Lecture Notes in Geoinformation and Cartography, 125–42. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-14745-7_8.
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Dębski, Roman, e Rafał Dreżewski. "Surrogate-Assisted Ship Route Optimisation". In Computational Science – ICCS 2023, 395–409. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-36024-4_31.
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Hurtado-Pérez, A. B., J. J. Hernández-Gómez, M. F. Mata-Rivera e G. A. Yáñez-Casas. "Efficient Computation Techniques for a Standard Topology Optimisation Routine". In Communications in Computer and Information Science, 94–118. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-77290-0_7.
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Kim, Dae Gyu, David Corne e Peter Ross. "Industrial plant pipe-route optimisation with genetic algorithms". In Parallel Problem Solving from Nature — PPSN IV, 1012–21. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/3-540-61723-x_1064.
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Qureshi, Rehan, e Arek Dadej. "Prefix Delegation Based Route Optimisation in Cooperative Ad Hoc Interconnected Mobile Networks". In Ad Hoc Networks, 302–15. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36958-2_21.
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Alvarez, Pablo, Iosu Lerga, Adrian Serrano e Javier Faulin. "Considering Congestion Costs and Driver Behaviour into Route Optimisation Algorithms in Smart Cities". In Smart Cities, 39–50. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59513-9_5.
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Attivilli, Ravali, Afraa Noureen, Vaibhavi Sachin Rao e Siddhaling Urolagin. "A Real-Time Graphical Representation of Various Path Finding Algorithms for Route Optimisation". In Advances in Data-driven Computing and Intelligent Systems, 479–93. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-0981-0_37.
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Wilkie, Bernard, Karla Muñoz Esquivel e Jamie Roche. "An LSTM Framework for the Effective Screening of Dementia for Deployment on Edge Devices". In Communications in Computer and Information Science, 21–37. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-59080-1_2.
Testo completoAbstract (sommario):
AbstractDementia is a series of neurodegenerative disorders that affect 1 in 4 people over the age of 80 and can greatly reduce the quality of life of those afflicted. Alzheimer’s disease (AD) is the most common variation, accounting for roughly 60% of cases. The current financial cost of these diseases is an estimated $1.3 trillion per year. While treatments are available to help patients maintain their mental function and slow disease progression, many of those with AD are asymptomatic in the early stages, resulting in late diagnosis. The addition of the routine testing needed for an effective level of early diagnosis would put a costly burden on both patients and healthcare systems. This research proposes a novel framework for the modelling of dementia, designed for deployment in edge hardware. This work extracts a wide variety of thoroughly researched Electroencephalogram (EEG) features, and through extensive feature selection, model testing, tuning, and edge optimization, we propose two novel Long Short-Term Memory (LSTM) neural networks. The first, uses 4 EEG sensors and can classify AD and Frontotemporal Dementia from cognitively normal (CN) subjects. The second, requires 3 EEG sensors and can classify AD from CN subjects. This is achieved with optimisation that reduces the model size by 83×, latency by 3.7×, and performs with an accuracy of 98%. Comparative analysis with existing research shows this performance exceeds current less portable techniques. The deployment of this model in edge hardware could aid in routine testing, providing earlier diagnosis of dementia, reducing the strain on healthcare systems, and increasing the quality of life for those afflicted with the disease.
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García, María González, Rodrigo de la Calle Alonso, Álvaro Lozano Murciego e María N. Moreno-García. "Van Trip Design System Based on Route Optimisation and an Innovative Cold-Start Solution for POI Recommender Systems". In Advances in Intelligent Systems and Computing, 283–93. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-38344-1_27.
Testo completoAtti di convegni sul tema "Optimisation du routage"
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Reimer, N. "Ice Route Optimisation". In The International Conference on Ice Class Ships 2012. RINA, 2012. http://dx.doi.org/10.3940/rina.ice.2012.14.
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Milli, Andrea, e Olivier Bron. "Fully Parametric High-Fidelity CFD Model for the Design Optimisation of the Cyclic Stagger Pattern of a Set of Fan Outlet Guide Vanes". In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59416.
Testo completoAbstract (sommario):
The present paper deals with the redesign of cyclic variation of a set of fan outlet guide vanes by means of high-fidelity full-annulus CFD. The necessity for the aerodynamic redesign originated from a change to the original project requirement, when the customer requested an increase in specific thrust above the original engine specification. The main objectives of this paper are: 1) make use of 3D CFD simulations to accurately model the flow field and identify high-loss regions; 2) elaborate an effective optimisation strategy using engineering judgement in order to define realistic objectives, constraints and design variables; 3) emphasise the importance of parametric geometry modelling and meshing for automatic design optimisation of complex turbomachinery configurations; 4) illustrate that the combination of advanced optimisation algorithms and aerodynamic expertise can lead to successful optimisations of complex turbomachinery components within practical time and costs constrains. The current design optimisation exercise was carried out using an in-house set of software tools to mesh, resolve, analyse and optimise turbomachinery components by means of Reynolds-averaged Navier-Stokes simulations. The original configuration was analysed using the 3D CFD model and thereafter assessed against experimental data and flow visualisations. The main objective of this phase was to acquire a deep insight of the aerodynamics and the loss mechanisms. This was important to appropriately limit the design scope and to drive the optimisation in the desirable direction with a limited number of design variables. A mesh sensitivity study was performed in order to minimise computational costs. Partially converged CFD solutions with restart and response surface models were used to speed up the optimisation loop. Finally, the single-point optimised circumferential stagger pattern was manually adjusted to increase the robustness of the design at other flight operating conditions. Overall, the optimisation resulted in a major loss reduction and increased operating range. Most important, it provided the project with an alternative and improved design within the time schedule requested and demonstrated that CFD tools can be used effectively not only for the analysis but also to provide new design solutions as a matter of routine even for very complex geometry configurations.
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Romdhani, Imed, Jose Munoz, Hatem Bettahar e Abdelmadjid Bouabdallah. "Mobile Multicast Route Optimisation". In 2006 IEEE International Conference on Communications. IEEE, 2006. http://dx.doi.org/10.1109/icc.2006.255060.
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Kedia, Raja Kumar, e B. Krishna Naick. "Review of vehicle route optimisation". In 2017 2nd IEEE International Conference on Intelligent Transportation Engineering (ICITE). IEEE, 2017. http://dx.doi.org/10.1109/icite.2017.8056881.
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Waldock, Antony, e David Corne. "Multiple objective optimisation applied to route planning". In the 13th annual conference. New York, New York, USA: ACM Press, 2011. http://dx.doi.org/10.1145/2001576.2001821.
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Persky, Rodney, Emilie Sauret e Lin Ma. "Optimisation Methods for Coupled Thermodynamic and 1D Design of Radial-Inflow Turbines". In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21665.
Testo completoAbstract (sommario):
Optimisation is a fundamental step in the turbine design process, especially in the development of non-classical designs of radial-inflow turbines working with high-density fluids in low-temperature Organic Rankine Cycles (ORCs). The present work discusses the simultaneous optimisation of the thermodynamic cycle and the one-dimensional design of radial-inflow turbines. In particular, the work describes the integration between a 1D meanline preliminary design code adapted to real gases and the performance estimation approach for radial-inflow turbines in an established ORC cycle analysis procedure. The optimisation approach is split in two distinct loops; the inner operates on the 1D design based on the parameters received from the outer loop, which optimises the thermodynamic cycle. The method uses parameters including brine flow rate, temperature and working fluid, shifting assumptions such as head and flow coefficients into the optimisation routine. The discussed design and optimisation method is then validated against published benchmark cases. Finally, using the same conditions, the coupled optimisation procedure is extended to the preliminary design of a radial-inflow turbine with R143a as working fluid in realistic geothermal conditions and compared against results from commercially-available software RITAL from Concepts-NREC.
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Goojar, Arunya, Parth Verma, Nitin Singh, Shubhradeep Debnath e Neha Tyagi. "Intelligent Carpooling - Machine Learning Route and Pickup Optimisation". In 2024 IEEE International Conference on Computing, Power and Communication Technologies (IC2PCT). IEEE, 2024. http://dx.doi.org/10.1109/ic2pct60090.2024.10486491.
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Ojo, Oluwatayo Babatope, Uyioghosa Igie e Pericles Pilidis. "Techno-Economic Optimisation of Gas Compressor Station Location As a Decision Variable". In ASME Turbo Expo 2024: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/gt2024-126805.
Testo completoAbstract (sommario):
Abstract An economical natural gas transportation will require the lowest possible capital and operating expenditures over its lifecycle. To attain these conditions, the designers and investors must estimate the number of compressor stations (CS) that are needed along the pipeline route. More so is the need to determine their optimised locations at various pipeline segments along the pipeline. This study considers the techno-economic optimisation of the compressor station and pipeline segments, making up the proposed Trans-Saharan Gas Pipeline (TSGP) project. The optimised lifecycle cost, CS locations and pipeline segments are evaluated with the main aim of minimising costs. A SIMULINK model is developed using the techno-economic and environmental risk analysis (TERA) framework. The model is incorporated with an optimiser that enables an economic analysis of the TERA framework. Including the optimiser affects the outcome of the TERA in terms of the lifecycle cost. The optimisation problems are formulated considering the compressor station location as the decision variable. The lifecycle cost of the compressor stations and pipeline system is the objective function. A scenarios-based techno-economic optimisation study is performed to mimic the standard compressor station and pipeline system network configurations in the real world. The baseline case consists of 18 compressor stations at fixed locations along the pipeline route. The results show 12 compressor station locations along the pipeline route with a reduction in the lifecycle cost by 12.95% in one of the optimised scenarios compared to the baseline case. The net present value is $28.77 billion assuming a discount rate of 15%. The optimised compressor station locations are at 1, 38, 76, 113, 150, 186, 222, 260, 296, 332, 368, and 408 segments of the pipeline. The outcome of the analyses shows the importance of the two-level optimisation algorithm utilised by the SIMULINK model for the integrated TERA. Hence, this study shows the potential of the TERA modelling and CS location optimisation method utilised in this research in guiding decision-makers on the selection of compressor-turbine configurations. These configurations will give the optimal lifecycle cost at the optimised compressor station locations along the pipeline route.
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Doherty, James P., e Barry M. Lehane. "An Automated Approach for Designing Monopiles Subjected to Lateral Loads". In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61603.
Testo completoAbstract (sommario):
This paper describes an automated algorithm for determining the length and diameter of monopile foundations subject to lateral loads with the aim of minimising the pile weight, whilst satisfying both ultimate and serviceability limit states. The algorithm works by wrapping an optimisation routine around a finite element p - y model for laterally loaded piles. The objective function is expressed as a function representing the pile volume, while the ultimate limit state and serviceability limit states are expressed as optimisation constraints. The approach was found to be accurate and near instantaneous when compared to manual design procedures and may improve design outcomes and reduce design time and costs.
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Cravero, C., e W. N. Dawes. "Throughflow Design Using an Automatic Optimisation Strategy". In ASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/97-gt-294.
Testo completoAbstract (sommario):
A procedure has been developed to optimise the design of an axial turbine stage. A standard, streamline curvature throughflow code, with standard loss correlations, was combined with a simple parameterisation of the geometry and a standard, constrained minimisation routine. An analytic differentiation of the loss correlations was also carried out to provide insight into the influence of each of the flow variables on the stage performance. The complete procedure has been demonstrated on a single high pressure axial steam turbine stage. The initial and optimised configurations for the stage were then analysed using a 3D Navier-Stokes solver. The results confirm the improved performance and give some additional insight into the origin of the benefits.