Academic literature on the topic 'Algorithmes de mariage'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Algorithmes de mariage.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Algorithmes de mariage"

1

Bacci, M. Livi, and Gustavo De Santis. "Population reproduction. A method of breakdown and estimation (Population, 5,1997)." Population Vol. 53, HS2 (December 2, 1998): 245–66. http://dx.doi.org/10.3917/popu.p1998.10n2.0266.

Full text
Abstract:
Résumé De Santis (Gustavo), Livi Bacci (Massimo). - La reproduction des populations : une méthode de décomposition et d'estimation Dans cet article, on montre comment, sous certaines hypothèses peu restrictives, on peut décomposer une mesure classique de la reproduction Ro en une série de composantes multiplicatives, chacune reflétant une dimension spécifique (intensité ou fréquence) de la nuptialité, de la mortalité, de la fécondité, et si l'on veut, de la migration. Cette idée peut être exploitée de deux façons : - soit on peut obtenir des données ou des estimations relativement complètes des processus démographiques, à partir, par exemple, d'un recensement ou d'un état des âmes où il est possible d'appliquer la méthode des enfants présents au ménage et de calculer la proportion des célibataires aux différents âges ; - soit, au contraire, on ne peut pas calculer ces éléments, comme, par exemple, quand on obtient les données par reconstitution nominative des familles. Dans ce cas, il est préférable de suivre une méthode légèrement différente. Elle consiste à estimer le nombre moyen de filles naissant d'une génération de femmes soumises à la mortalité, à la migration et au mariage. En multipliant cette valeur par la durée de mariage fécond, on obtient une estimation de l'effectif total de la génération des filles et donc de la valeur de Ro. Quelques algorithmes simples sont proposés pour le calcul de l'âge moyen à l'accouchement et pour l'estimation, à cet âge, de la proportion de femmes mariées. Une application aux cas de l'Angleterre, de la France et de l'Allemagne révèle l'existence et la nature des différents régimes démographiques des XVIIe et XVIIIe siècles.
APA, Harvard, Vancouver, ISO, and other styles
2

Livi Bacci, Massimo, and Gustavo De Santis. "La reproduction des populations : une méthode de décomposition et d'estimation." Population Vol. 52, no. 5 (May 1, 1997): 1119–42. http://dx.doi.org/10.3917/popu.p1997.52n5.1142.

Full text
Abstract:
Résumé De Santis (Gustavo), Livi Bacci (Massimo). - La reproduction des populations: une méthode de décomposition et d'estimation Dans cet article, on montre comment, sous certaines hypothèses peu restrictives, on peut décomposer une mesure classique de la reproduction Ro en une série de composantes multiplicatives, chacune reflétant une dimension spécifique (intensité ou fréquence) de la nuptialité, de la mortalité, de la fécondité, et si l'on veut, de la migration. Cette idée peut être exploitée de deux façons : - soit on peut obtenir des données ou des estimations relativement complètes des processus démographiques, à partir, par exemple, d'un recensement ou d'un état des âmes où il est possible d'appliquer la méthode des enfants présents au ménage et de calculer la proportion des célibataires aux différents âges ; - soit, au contraire, on ne peut pas calculer ces éléments, comme, par exemple, quand on obtient les données par reconstitution nominative des familles. Dans ce cas, il est préférable de suivre une méthode légèrement différente. Elle consiste à estimer le nombre moyen de filles naissant d'une génération de femmes soumises à la mortalité, à la migration et au mariage. En multipliant cette valeur par la durée de mariage fécond, on obtient une estimation de l'effectif total de la génération des filles et donc de la valeur de Ro. Quelques algorithmes simples sont proposés pour le calcul de l'âge moyen à l'accouchement et pour l'estimation, à cet âge, de la proportion de femmes mariées. Une application aux cas de l'Angleterre, de la France et de l'Allemagne révèle l'existence et la nature des différents régimes démographiques des XVIIe et XVIIIe siècles.
APA, Harvard, Vancouver, ISO, and other styles
3

Newton, P. F. "Algorithmic versions of black spruce stand density management diagrams." Forestry Chronicle 73, no. 2 (April 1, 1997): 257–65. http://dx.doi.org/10.5558/tfc73257-2.

Full text
Abstract:
Algorithmic versions of stand density management diagrams (SDMDs) were developed for natural and managed black spruce (Picea mariana (Mill.) B.S.P.) stands. Specifically, the IBM-compatible PC-based algorithms (1) graphically illustrate site-specific size-density trajectories for eight user-specified initial density regimes, (2) given (1), calculate and subsequent tabulate periodic yield estimates (mean dominant height, density, mean volume, total volume, total merchantable volume, quadratic mean diameter, and basal area), and (3) given (2), graphically illustrate empirically-derived yield production curves for total merchantable volume ha−1 and stems m−3 with user-specified operability criteria superimposed. Instructions on acquiring the executable algorithmic versions including the required graphical subroutines via the Internet are described. Currently, the algorithms are restricted in applicability to central insular Newfoundland. Key words: stand density management diagrams, black spruce, algorithms, microcomputer, World-Wide Web (WWW), hypertext browser, file transfer protocol (FTP).
APA, Harvard, Vancouver, ISO, and other styles
4

Zhou Yingfeng, 周迎峰, 张荣芬 Zhang Rongfen, 刘宇红 Liu Yuhong, and 李宽 Li Kuan. "基于RetinaNet的海洋鱼类检测算法." Laser & Optoelectronics Progress 60, no. 10 (2023): 1010014. http://dx.doi.org/10.3788/lop213356.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Öztürk, Nurcan, and Hasan Tahsin Öztürk. "DENİZE DEŞARJ YAPILARININ ÖĞRETME VE ÖĞRENME TABANLI ALGORITMAYLA OPTİMUM TASARIMI." E-Journal of New World Sciences Academy 13, no. 3 (July 30, 2018): 235–42. http://dx.doi.org/10.12739/nwsa.2018.13.3.2a0153.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Nguyen, Vi H., and Duc T. Nguyen. "Marine Quay Crane Scheduling Using a Combined Modified Genetic Algorithm and Priority Rules Approach." International Journal of Materials, Mechanics and Manufacturing 7, no. 1 (February 2019): 21–26. http://dx.doi.org/10.18178/ijmmm.2019.7.1.422.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Newton, Peter F. "Regional-Specific Algorithmic Stand Density Management Diagram for Black Spruce." Northern Journal of Applied Forestry 15, no. 2 (June 1, 1998): 94–97. http://dx.doi.org/10.1093/njaf/15.2.94.

Full text
Abstract:
Abstract A regional-specific algorithmic stand density management diagram was developed for managed upland black spruce (Picea mariana [Mill.] B.S.P.) stands applicable to Newfoundland, New Brunswick, Quebec, and Ontario. Specifically, the IBM-compatible PC-based algorithm (1) graphically illustrates site-specific size-density trajectories for 8 user-specified initial density regimes, (2) calculates and subsequently tabulates periodic yield estimates from 5-50 yr by 5 yr intervals for mean dominant height, density, mean volume, total volume, total merchantable volume, quadratic mean diameter, and basal area, (3) given (2), graphically illustrates empirically derived yield production curves for total merchantable volume per hectare and number of stems per cubic meter with user-specified operability criteria superimposed, and (4) given (3), calculates and subsequently tabulates the minimum time required to attain operability status. The utility of the algorithm is demonstrated within the context of determining site-specific initial densities required to attain user-specified operability criteria. Procedures for acquiring the executable version via the Internet are also included. North. J. Appl. For. 15(2):94-97.
APA, Harvard, Vancouver, ISO, and other styles
8

Lemenkova, Polina. "R Libraries {dendextend} and {magrittr} and Clustering Package scipy.cluster of Python For Modelling Diagrams of Dendrogram Trees." Carpathian Journal of Electronic and Computer Engineering 13, no. 3 (September 1, 2020): 5–12. http://dx.doi.org/10.2478/cjece-2020-0002.

Full text
Abstract:
AbstractThe paper presents a comparison of the two languages Python and R related to the classification tools and demonstrates the differences in their syntax and graphical output. It indicates the functionality of R and Python packages {dendextend} and scipy.cluster as effective tools for the dendrogram modelling by the algorithms of sorting and ranking datasets. R and Python programming languages have been tested on a sample dataset including marine geological measurements. The work aims to detect how bathymetric data change along the 25 bathymetric profiles digitized across the Mariana Trench. The methodology includes performed hierarchical cluster analysis with dendrograms and plotted clustermap with marginal dendrograms. The statistical libraries include Matplotlib, SciPy, NumPy, Pandas by Python and {dendextend}, {pvclust}, {magrittr} by R. The dendrograms were compared by the model-simulated clusters of the bathymetric ranges. The results show three distinct groups of the profiles sorted by the elevation ranges with maximal depths detected in a group of profiles 19-21. The dendrogram visualization in a cluster analysis demonstrates the effective representation of the data sorting, grouping and classifying by the machine learning algorithms. The programming codes presented in this study enable to sort a dataset in a similar research aimed to group data based on the similarity of attributes. Effective visualization by dendrograms is a useful modelling tool for the geospatial management where data ranking is required. Plotting dendrograms by R, comparing to Python, presented functional and sophisticated algorithms, refined design control and fine graphical data output. The interdisciplinary nature of this work consists in application of the coding algorithms for spatial data analysis.
APA, Harvard, Vancouver, ISO, and other styles
9

Yu, Lisan. "Global Air–Sea Fluxes of Heat, Fresh Water, and Momentum: Energy Budget Closure and Unanswered Questions." Annual Review of Marine Science 11, no. 1 (January 3, 2019): 227–48. http://dx.doi.org/10.1146/annurev-marine-010816-060704.

Full text
Abstract:
The ocean interacts with the atmosphere via interfacial exchanges of momentum, heat (via radiation and convection), and fresh water (via evaporation and precipitation). These fluxes, or exchanges, constitute the ocean-surface energy and water budgets and define the ocean's role in Earth's climate and its variability on both short and long timescales. However, direct flux measurements are available only at limited locations. Air–sea fluxes are commonly estimated from bulk flux parameterization using flux-related near-surface meteorological variables (winds, sea and air temperatures, and humidity) that are available from buoys, ships, satellite remote sensing, numerical weather prediction models, and/or a combination of any of these sources. Uncertainties in parameterization-based flux estimates are large, and when they are integrated over the ocean basins, they cause a large imbalance in the global-ocean budgets. Despite the significant progress that has been made in quantifying surface fluxes in the past 30 years, achieving a global closure of ocean-surface energy and water budgets remains a challenge for flux products constructed from all data sources. This review provides a personal perspective on three questions: First, to what extent can time-series measurements from air–sea buoys be used as benchmarks for accuracy and reliability in the context of the budget closures? Second, what is the dominant source of uncertainties for surface flux products, the flux-related variables or the bulk flux algorithms? And third, given the coupling between the energy and water cycles, precipitation and surface radiation can act as twin budget constraints—are the community-standard precipitation and surface radiation products pairwise compatible?
APA, Harvard, Vancouver, ISO, and other styles
10

Palma, Sindika Alifia, and Sandy Kosasi. "PENERAPAN FRAMEWORK CODEIGNITER UNTUK WEBSITE TOKO ONLINE PADA DASTER HITS PONTIANAK." Jurnal Informatika Progres 15, no. 1 (May 3, 2023): 13–22. http://dx.doi.org/10.56708/progres.v15i1.343.

Full text
Abstract:
Daster Hits pontianak has a need to expand its market share and manage valid data systems. The sales system currently used is traditional sellers and social media such as Instagram and WhatsApp, therefore the interaction between the store and customers is still limited, recording of transactions is still manual using a transaction book, and if customers want to find products they have to scroll Instagram or come directly to the store. The purpose of this research is to apply the CodeIgniter framework to build an online shop website which is expected to help the shop in promoting the product, manage product data, and expedite the product sales process. The research method used in this research is Design Science Research and the design method uses Extreme Programming. The system modeling used is the Unified Modeling Language (UML) and the software testing method uses white-box testing. The advantages of Daster Hits Pontianak Online Shop website are the features such as managing user profiles, product sales, detailed product information, online product orders and payment confirmation, searches using sequential search algorithms, managing product stocks using the Apriori algorithm, and notifications using push notifications. The process of making this program uses the PHP programming language and the MariaDB database.
APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic "Algorithmes de mariage"

1

Aliou, Diallo Aoudi Mohamed Habib. "Local matching algorithms on the configuration model." Electronic Thesis or Diss., Compiègne, 2023. http://www.theses.fr/2023COMP2742.

Full text
Abstract:
Nous proposons une alternative à l’approche prévalente dans les algorithmes de mariage en ligne. Basés sur le choix d’un critère de mariage, nous construisons des algorithmes dits locaux. Ces algorithmes sont locaux dans le sens où chacun des individus est tour à tour soumis au critère de mariage choisi. Ce qui nous amène à démontrer que le nombre de sommets qui finissent mariés lorsque chaque individu adopte une stratégie prédéfinie est solution d’une équation différentielle ordinaire. Grâce à cette approche nous prédisons les performances et comparons deux algorithmes/stratégies. Pour émuler l'asymptotique des graphes, nous utilisons le modèle de configuration basé sur un échantillonnage de la distribution de degré du graphe d'intérêt. Et globalement notre méthode peut être vue comme une généralisation de la Differential Equation Method de Wormald. Il est à noter que l’approche en ligne se concentre principalement sur les graphes bipartis
The present thesis constructs an alternative framework to online matching algorithms on large graphs. Using the configuration model to mimic the degree distributions of large networks, we are able to build algorithms based on local matching policies for nodes. Thus, we are allowed to predict and approximate the performances of a class of matching policies given the degree distributions of the initial network. Towards this goal, we use a generalization of the differential equation method to measure valued processes. Through-out the text, we provide simulations and a comparison to the seminal work of Karp, Vazirani and Vazirani based on the prevailing viewpoint in online bipartite matching
APA, Harvard, Vancouver, ISO, and other styles
2

Laveau, Marie. "Asynchronous Self-Stabilizing Stable Marriage." Electronic Thesis or Diss., université Paris-Saclay, 2020. http://www.theses.fr/2020UPASG008.

Full text
Abstract:
Le Problème du Mariage Stable (SMP) est un problème d'appariement où les participants ont des préférences à propos de leurs partenaires potentiels.L'objectif est de trouver un appariement optimal (stable dans un sens) au regard des préférences. Ce type d'appariement a de très nombreuses applications comme les affectations d'étudiants à des universités (APB ou ParcourSup), celles des internes en médecine aux hôpitaux, les choix des donneurs pour les patients en attente d'organe, la mise en rapport des taxis et de leurs clients ou encore la diffusion de contenu sur Internet.Certaines de ces applications peuvent être traitées de manière centralisée tandis que d'autres, de par leur nature distribuée et la complexité de leurs données, nécessitent un traitement différent. Par exemple, dans le contexte du Cloud-Computing, des machines virtuelles sont émulées par des machines réelles situées sur la terre entière.Un algorithme centralisé causerait des délais considérables dans les prises de décision tout en étant sensible aux défaillances, ce qui est inconcevable pour un service supposé disponible à tout moment. D'un autre côté, chaque fois que des personnes sont impliquées dans un appariement, elles ont le droit de garder privées leurs données personnelles et en particulier leur liste de préférences, qui peut contenir des informations sensibles.Par conséquent, il est souhaitable que les listes de préférence des personnes ne soient jamais transmises sur Internet, et encore moins rassemblées pour un traitement centralisé.C'est pourquoi la distribution, la tolérance aux défaillances (par auto-stabilisation) et la confidentialité sont les trois principaux mots-clés de cette thèse.Dans ce contexte, nous proposons deux solutions distribuées auto-stabilisantes. De telles solutions tolèrent les défaillances (e.g., corruptions de mémoire ou de messages) transitoires (ou de courte durée) de n'importe quels noeuds.La confidentialité des listes de préférences est garantie par les deux algorithmes que nous proposons : les listes ne sont pas partagées et seules des queries binaires et leurs réponses sont échangés.Une différence entre ces algorithmes est le modèle de communication : le premier algorithme utilise le modèle à état tandis que le second algorithme utilise le modèle à registre plus général.Dans les deux modèles, les exécutions se déroulent par pas atomiques et un démon (démon distribué inéquitable) exprime la notion d'asynchronisme.Avec ce démon, le temps de stabilisation peut être borné en terme de moves (pas locaux).Cette mesure de complexité permet d'évaluer avec précision la puissance de calcul nécessaire ou l'énergie dissipée par les exécutions de l'algorithme.Ce n'est pas le cas quand la complexité est évaluée en rounds, puisque le nombre de moves effectués dans un round n'est pas nécessairement borné.Le premier algorithme, basé sur la méthode centralisée de Ackermann et al. (SICOMP' 2011), résout le SMP en O(n⁴) moves.Il permet également de résoudre certaines variantes du SMP telles que le mariage stable avec indifférence, avec partenaires inacceptables, etc.Le point de départ du deuxième algorithme est le schéma de détection locale/correction globale de Awerbuch et al. (DA' 1994) : un algorithme non auto-stabilisant (devant être initialisé) mais avec la propriété d'être vérifiable localement peut être combiné avec un détecteur et un algorithme de réinitialisation.De cette combinaison résulte un algorithme auto-stabilisant.Malheureusement, la définition de la vérifiabilité locale de DA '1994 ne s'applique pas à notre cas (en particulier en raison du démon inéquitable).Nous proposons donc une nouvelle définition.De plus, nous concevons un algorithme de réinitialisation (reset) asynchrone, distribué et auto-stabilisant.L'algorithme résultant résout le SMP en θ(n)² moves
The Stable Marriage Problem (SMP) is a matching problem where participants have preferences over their potential partners.The objective is to find a matching that is optimal (stable in certain sens) with regard to these preferences.This type of matching has a lot of widely used applications such as the assignment of children to schools, interns to hospitals, kidney transplant patients to donors, as well as taxi scheduling or content delivery on the Internet.Some applications can be solved in a centralized way while others, due to their distributed nature and their complex data, need a different treatment.For example, when applying this problem to the Cloud-Computing context, virtual machines are emulated by real machines located all over the world.A centralized algorithm would cause unbearable delays and be sensible to failures, which is inconceivable for a service meant to be available at any time.On the other hand, when humans are to be matched or involved in a matching, they have the right to keep their personal data private and in particular their list of preferences.Consequently, the preference lists should not be transmitted on the Internet, and even less gathered for a centralized treatment.This is why, distribution, fault-tolerance (by self-stabilization) and privacy are the three main keywords of this thesis.In order to handle these challenges, we provide two distributed self-stabilizing solutions.Such solutions tolerate transient (or short-lived) failures (e.g., memory or message corruptions) of any nodes.The privacy of the preference lists is guaranteed by the two proposed algorithms: lists are not shared, only some binary queries and responses are transmitted.One of the differences between the two algorithms is the communication model: the first algorithm uses the state model while the second algorithm uses the more general register model.In both models, executions proceed in atomic steps and a daemon (distributed unfair daemon) conveys the notion of asynchrony.Under this daemon, the stabilization time can be bounded in term of moves (local computations).This complexity metrics allows to evaluate the necessary computational power or the energy consumption of the algorithm's executions.This is not the case when the stabilization time is measured in rounds since an unbounded number of moves may be executed during a round.The first algorithm, based on the centralized method of Ackermann et al. (SICOMP' 2011), solves the problem in O(n⁴) moves.It also solves some variants of SMP such as the Stable Marriage with indifference, with unacceptable partners, etc.The starting point of the second algorithm is the local detection/global correction scheme of Awerbuch et al. (DA' 1994): a non-self-stabilizing algorithm (with initialization) that satisfies the property of local checkability can be combined with a detector and a reset algorithms.The result of this composition is a self-stabilizing version of the given algorithm.Unfortunately, local checkability definition of DA '1994 does not apply to our case (in particular due to the unfair daemon).Consequently, we propose a new definition.Furthermore, we design a distributed self-stabilizing asynchronous reset algorithm. Using it, the resulting composed algorithm solves SMP in θ(n)² moves in a self-stabilizing way
APA, Harvard, Vancouver, ISO, and other styles
3

Mariano, Artur [Verfasser], Christian [Akademischer Betreuer] Bischof, and Pingali [Akademischer Betreuer] Keshav. "High performance algorithms for lattice-based cryptanalysis / Artur Mariano ; Christian Bischof, Pingali Keshav." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/112001459X/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Park, Jinhyung. "Pipe-routing algorithm development for a ship engine room design." Thesis, online access from Digital Dissertation Consortium access full-text, 2002. http://libweb.cityu.edu.hk/cgi-bin/er/db/ddcdiss.pl?3062999.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Howard, James A. E. "Application of the sequential t-test algorithm for analysing regime shifts to the southern Benguela ecosystem." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/6481.

Full text
Abstract:
Includes bibliographical references (leaves 69-74).
Includes abstract.
Long-term ecosystem changes, such as regime shifts, have occurred in several marine ecosystems worldwide. Multivariate statistical methods have been used to detect such changes, but they have to date not been applied to the southern Benguela ecosystem. A weakness of many of the methods is that they require long time series data and do not provide robust results at the end of time series. A new method known as the sequential t-test algorithm for analysing regime shifts (STARS) is applied to a set of biological state variables and environmental and anthropogenic forcing variables in the southern Benguela.
APA, Harvard, Vancouver, ISO, and other styles
6

Maneepan, Komsan. "Genetic algorithm based optimisation of FRP composite plates in ship structures." Thesis, University of Southampton, 2007. https://eprints.soton.ac.uk/52012/.

Full text
Abstract:
Composite materials (herein means Fibre Reinforced Plastic, FRP) are increasingly usedin the construction of marine vehicles because of their outstanding strength, stiffness and light weight properties. However, the use of FRP comes with difficulties in the design process as a result of the large number of design variables involved: composite material design, topologies and laminate schemes. All variables are related to each other leading to a high dimensional and flexible design space. It is hard to use traditional design methods in order to gain solutions for an initial design stage in a short time. Hence, this thesis deals with the presentation of a structural synthesis (optimisation framework) for plate components of composite ship structures. The framework broadly consists of an optimisation technique and structural analytical methods. To make the framework compatible with the nature of composite ship structural design problems, the Genetic Algorithm (GA) is selected as the optimisation tool because of its robustness, its ability in dealing with both continuous and discrete variables and its excellent searching for a global optimum. The typical plate types in a ship structure are the stiffened and unstiffened plates. For a stiffened plate, the combination of the grillage analysis of energy method based on Navier solution and an equivalent elastic properties approach are introduced. Using this, it is possible to produce layer by layer optimisation results for the base plate, web and crown of the stiffened plate. Unfortunately, solutions of the adopted grillage analysis do not cover the mechanical behaviour of the plate between stiffeners so the Higher-Order Shear Deformation Theory (HSDT) must be employed. This method provides accurate solutions for thin to moderately thick plates with a compromised computational time. Then stiffness, strength and stability can be considered in the design problem. In addition, to achieve the program of the structural synthesis, various computational modules are implemented according to the evaluation of composite micromechanics properties, maximum stress failure criteria and structural weight function. Then the main modules are validated with available resources. The usefulness of the program has been proved by comparing it with the optimal solutions from finite element software. Finally, many application examples of secondary and tertiary composite ship structures are presented. The optimal results prove the success of the optimisation framework. This could be evidence for further improvement to obtain a valuable structural optimisation tool.
APA, Harvard, Vancouver, ISO, and other styles
7

YE, Zi. "Traitement statistique de l'information et du signal pour l'internet des objets sous-marins." Thesis, Institut polytechnique de Paris, 2021. https://tel.archives-ouvertes.fr/tel-03179373.

Full text
Abstract:
On assiste au développement des activités humaines liées au monde océanique, mais aucune norme n'a encore émergé pour l'Internet des objets appliqué aux objets autonomes marins. Bien qu'elle possède une bande passante limitée, l'onde acoustique est le seul moyen de communiquer sur des distances importantes et elle est donc utilisée par de nombreux systèmes sous-marins pour communiquer, naviguer ou déduire des informations sur l'environnement. Cela a conduit à une forte demande de réseaux sans fil qui nécessitent à la fois une bonne efficacité spectrale et énergétique avec la faible complexité des algorithmes associés. Par conséquent, au cours de ce doctorat, nous avons proposé plusieurs solutions originales pour relever le défi de développer des techniques numériques, capables de faire face au canal acoustique.En raison d’une diversité inhérente d'espace du signal (SSD), les constellations tournées permettent de meilleures performances théoriques que les constellations conventionnelles et ce, sans détérioration spectrale. Nous passons en revue les propriétés structurelles des constellations tournées M-QAM uniformément projetées, afin de proposer une technique de demapping souple à faible complexité pour les canaux à fading. Puis, nous proposons une technique originale de réduction du PAPR pour les systèmes OFDM utilisant les constellations tournées. Afin de réduire la complexité du décodage aveugle, nous nous appuyons sur les propriétés des constellations tournées M-QAM uniformément projetées, pour concevoir un estimateur de faible complexité. De plus, pour faire face à la sélectivité du canal acoustique, nous avons proposé un turbo-détecteur parcimonieux adaptatif avec seulement quelques coefficients à mettre à jour afin de réduire la complexité. Enfin, nous avons proposé un algorithme original auto-optimisé pour lequel les tailles de pas de l'égaliseur sont mises à jour de manière adaptative et assistées par des informations souples de manière itérative, afin de répondre à l'exigence de convergence rapide et de faible erreur quadratique sur des canaux variant rapidement dans le temps
There has been recently a large development of human activities associated to the ocean world, where no standard has emerged for the Internet of Things (IoT) linked to marine autonomous objects. Though it has a limited bandwidth, the acoustic wave is the only way to communicate over average to large distances and it is thus used by many underwater systems to communicate, navigate, or infer information about the environment. This led to a high demand for wireless networks that require both spectral efficiency and energy efficiency with the associated low-complexity algorithms. Therefore, in this Ph.D. thesis, we proposed several original solutions to face this challenge.Indeed, due to the inherent Signal Space Diversity (SSD), rotated constellations allow better theoretical performance than conventional constellations with no spectral spoilage. We review the structural properties of uniformly projected rotated M-QAM constellations, so as to propose a low complexity soft demapping technique for fading channels. Then, we present an original blind technique for the reduction of the PAPR for OFDM systems using the rotated constellations with SSD. In order to reduce the complexity of blind decoding for this technique, we again rely on the properties of uniformly projected M-QAM rotated constellations to design a low-complexity estimator. Moreover, to face the selectivity of the acoustic channel, we suggest a sparse adaptive turbo detector with only a few taps to be updated in order to lower down the complexity burden. Finally, we have proposed an original self-optimized algorithm for which the step-sizes of both the equalizer and the phase estimator are updated adaptively and assisted by soft-information in an iterative manner, so as to meet the requirement of fast convergence and low MSE over time-varying channels
APA, Harvard, Vancouver, ISO, and other styles
8

Vega, Emanuel Pablo. "Conception orientée-tâche et optimisation de systèmes de propulsion reconfigurables pour robots sous-marins autonomes." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0067/document.

Full text
Abstract:
Dans ce travail, l’optimisation de la propulsion et de la commande des AUV (Autonomous Underwater Vehicles en anglais) est développée. Le modèle hydrodynamique de l’AUV est examiné. Egalement, son système de propulsion est étudié et des modèles pour des solutions de propulsion différentes (fixe et vectorielle) sont développés dans le cadre de la mobilité autonome.Le modèle et l’identification de la technologie de propulsion dite fixe sont basés sur un propulseur disponible commercialement. Le système de propulsion vectoriel est basé sur un prototype de propulseur magneto-couplé reconfigurable (PMCR) développé à l’IRDL-ENIB.Une méthode de commande non linéaire utilisant le modèle hydrodynamique de l’AUV est développée et son adaptation à deux systèmes de propulsion est présentée. Des analyses portant sur la commandabilité du robot et l’application de cette commande à différents systèmes sont proposées. L’optimisation globale est utilisée pour trouver des topologies propulsives et des paramètres de commande adaptés à la réalisation de tâches robotiques spécifiques. L’optimisation réalisée permet de trouver des solutions capables d’assurer le suivi de trajectoire et de minimiser la consommation énergétique du robot. L’optimisation utilise un algorithme génétique (algorithme évolutionnaire), une méthode d’optimisation stochastique appliquée ici à la conception orientée tâche de l’AUV. Les résultats de cette optimisation peuvent être utilisés comme une étape préliminaire dans la conception des AUVs, afin de donner des pistes pour améliorer les capacités de la propulsion.La technique d’optimisation est également appliquée au robot RSM (fabriqué au sein de l’IRDL-ENIB) en modifiant seulement quelques paramètres de sa topologie propulsive. Cela afin d’obtenir des configurations de propulsion adaptées au cours d’une seule et même mission aux spécificités locomotrices des tâches rencontrées : reconfiguration dynamique de la propulsion de l’AUV
In this PhD thesis, the optimization of the propulsion and control of AUVs is developed. The hydrodynamic model of the AUVs is examined. Additionally, AUV propulsion topologies are studied and models for fixed and vectorial technology are developed. The fixed technology model is based on an off the shelf device, while the modeled vectorial propulsive system is based on a magnetic coupling thruster prototype developed in IRDL (Institut de Recherche Dupuy de Lôme) at ENI Brest. A control method using the hydrodynamic model is studied, its adaptation to two AUV topologies is presented and considerations about its applicability will be discussed. The optimization is used to find suitable propulsive topologies and control parameters in order to execute given robotic tasks, speeding up the convergence and minimizing the energy consumption. This is done using a genetic algorithm, which is a stochastic optimization method used for task-based design.The results of the optimization can be used as a preliminary stage in the design process of an AUV, giving ideas for enhanced propulsive configurations. The optimization technique is also applied to an IRDL existing robot, modifying only some of the propulsive topology parameters in order to readily adapt it to different tasks, making the AUV dynamically reconfigurable
APA, Harvard, Vancouver, ISO, and other styles
9

Gallego, Bonet Guillermo. "Variational image processing algorithms for the stereoscopic space-time reconstruction of water waves." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39480.

Full text
Abstract:
A novel video observational method for the space-time stereoscopic reconstruction of dynamic surfaces representable as graphs, such as ocean waves, is developed. Variational optimization algorithms combining image processing, computer vision and partial differential equations are designed to address the problem of the recovery of the shape of an object's surface from sequences of synchronized multi-view images. Several theoretical and numerical paths are discussed to solve the problem. The variational stereo method developed in this thesis has several advantages over existing 3-D reconstruction algorithms. Our method follows a top-down approach or object-centered philosophy in which an explicit model of the target object in the scene is devised and then related to image measurements. The key advantages of our method are the coherence (smoothness) of the reconstructed surface caused by a coherent object-centered design, the robustness to noise due to a generative model of the observed images, the ability to handle surfaces with smooth textures where other methods typically fail to provide a solution, and the higher resolution achieved due to a suitable graph representation of the object's surface. The method provides competitive results with respect to existing variational reconstruction algorithms. However, our method is based upon a simplified but complete physical model of the scene that allows the reconstruction process to include physical properties of the object's surface that are otherwise difficult to take into account with existing reconstruction algorithms. Some initial steps are taken toward incorporating the physics of ocean waves in the stereo reconstruction process. The developed method is applied to empirical data of ocean waves collected at an off-shore oceanographic platform located off the coast of Crimea, Ukraine. An empirically-based physical model founded upon current ocean engineering standards is used to validate the results. Our findings suggest that this remote sensing observational method has a broad impact on off-shore engineering to enrich the understanding of sea states, enabling improved design of off-shore structures. The exploration of ways to incorporate dynamical properties, such as the wave equation, in the reconstruction process is discussed for future research.
APA, Harvard, Vancouver, ISO, and other styles
10

Nagarajan, Nishatha. "Target Tracking Via Marine Radar." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1345125374.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Books on the topic "Algorithmes de mariage"

1

Knuth, Donald Ervin. Stable marriage and its relation to other combinatorial problems: An introduction to the mathematical analysis of algorithms. Providence, R.I: American Mathematical Society, 1997.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Kaandorp, Jaap A. The Algorithmic Beauty of Seaweeds, Sponges and Corals. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Walsh, William J. Carrier optimization launch algorithm: An optimization model to maximize the number of tactically tasked sorties under constraint restriction. Monterey, Calif: Naval Postgraduate School, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Levitin, Anany, and Maria Levitin. Algorithmic Puzzles. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199740444.001.0001.

Full text
Abstract:
While many think of algorithms as specific to computer science, at its core algorithmic thinking is defined by the use of analytical logic to solve problems. This logic extends far beyond the realm of computer science and into the wide and entertaining world of puzzles. In Algorithmic Puzzles, Anany and Maria Levitin use many classic brainteasers as well as newer examples from job interviews with major corporations to show readers how to apply analytical thinking to solve puzzles requiring well-defined procedures. The book's unique collection of puzzles is supplemented with carefully developed tutorials on algorithm design strategies and analysis techniques intended to walk the reader step-by-step through the various approaches to algorithmic problem solving. Mastery of these strategies--exhaustive search, backtracking, and divide-and-conquer, among others--will aid the reader in solving not only the puzzles contained in this book, but also others encountered in interviews, puzzle collections, and throughout everyday life. Each of the 150 puzzles contains hints and solutions, along with commentary on the puzzle's origins and solution methods. The only book of its kind, Algorithmic Puzzles houses puzzles for all skill levels. Readers with only middle school mathematics will develop their algorithmic problem-solving skills through puzzles at the elementary level, while seasoned puzzle solvers will enjoy the challenge of thinking through more difficult puzzles.
APA, Harvard, Vancouver, ISO, and other styles
5

The Algorithmic Beauty of Seaweeds, Sponges and Corals. Springer, 2001.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Marghany, Maged. Automatic Detection Algorithms of Oil Spill in Radar Images. Taylor & Francis Group, 2021.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Marghany, Maged. Automatic Detection Algorithms of Oil Spill in Radar Images. Taylor & Francis Group, 2019.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Automatic Detection Algorithms of Oil Spill in Radar Images. Taylor & Francis Group, 2019.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Marghany, Maged. Automatic Detection Algorithms of Oil Spill in Radar Images. Taylor & Francis Group, 2019.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

O'Kane, Mike. Web-Based Introduction to Programming: Essential Algorithms, Syntax, and Control Structures Using PHP, HTML, and MariaDB/MySQL. Carolina Academic Press, 2017.

Find full text
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "Algorithmes de mariage"

1

Ahmad, Imran, and Athapol Noomhorm. "Glycans predictive modeling using modern algorithms." In Marine Glycobiology, 415–22. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2016. http://dx.doi.org/10.1201/9781315371399-31.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Borstad, Gary A., Edward J. Carpenter, and Jim F. R. Gower. "Development of Algorithms for Remote Sensing of Trichodesmium Blooms." In Marine Pelagic Cyanobacteria: Trichodesmium and other Diazotrophs, 193–210. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-015-7977-3_12.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Nicolas, Florian, Andreas Arnold-Bos, Isabelle Quidu, and Benoît Zerr. "Fast Fourier-Based Block-Matching Algorithm for Sonar Tracks Registration in a Multiresolution Framework." In Marine Robotics and Applications, 1–14. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-70724-2_1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Shi, Yang, Chao Shen, Henglai Wei, and Kunwu Zhang. "Efficient Implementation Algorithms for NMPC-Based AUV Trajectory-Tracking Control." In Advanced Model Predictive Control for Autonomous Marine Vehicles, 145–79. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-19354-5_8.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Nicolas, Florian, Andreas Arnold-Bos, Isabelle Quidu, and Benoît Zerr. "Erratum to: Fast Fourier-Based Block-Matching Algorithm for Sonar Tracks Registration in a Multiresolution Framework." In Marine Robotics and Applications, E1. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-70724-2_10.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Gong, In-Young, Yeon-Gyu Kim, Chang-Min Lee, Jin-Whan Kim, and Han-Jin Lee. "Development of harbor capability assessment simulation system by the application of fuzzy algorithm." In Marine Simulation and Ship Manoeuvrability, 161–67. London: Routledge, 2021. http://dx.doi.org/10.1201/9780203748077-20.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Kuperman, W. A., M. D. Collins, and H. Schmidt. "A Fast Simulated Annealing Algorithm for the Inversion of Marine Sediment Seismo-Acoustic Parameters." In Shear Waves in Marine Sediments, 521–28. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3568-9_60.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Chen, Yuhan, Wengang Mao, and Chi Zhang. "Different strategies to improve isochrone voyage optimization algorithm." In Advances in the Analysis and Design of Marine Structures, 53–61. London: CRC Press, 2023. http://dx.doi.org/10.1201/9781003399759-6.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Wu, Wei, Chunshui Xiong, Xuan Guo, and Dongming Zhao. "Improved particle swarm optimization and DDQN algorithm for multi-UUV path planning." In Sustainable Development and Innovations in Marine Technologies, 343–50. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003358961-43.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Cai, Y., and J. Jelovica. "Comparison of metaheuristic algorithms and constraint handling approaches for multi-objective optimization of a tanker." In Advances in the Analysis and Design of Marine Structures, 801–8. London: CRC Press, 2023. http://dx.doi.org/10.1201/9781003399759-88.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Algorithmes de mariage"

1

Ates, Abdullah, and YangQuan Chen. "Fractional Order Filter Discretization With Marine Predators Algorithm." In ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/detc2021-67611.

Full text
Abstract:
Abstract In this study, discrete time models of continuous time fractional order filters are obtained by using the Marine Predators Algorithm (MPA). Marine Predators optimization algorithm is a population-based heuristic method. This method is inspired by the hunting behavior of marine predators. The algorithm works on three basic phases. These phases occur according to the difference or equality of the velocity of the prey and the predator. As it is known, uniform distribution is generally used in stochastic based optimization algorithms. However, in the MPA method, Brownian and Levy distributions are also used as well as uniform distribution. First, continuous time frequency responses of fractional order filters are generated. Then, fourth order discrete time filters are designed that can give similar responses with generated continues time filter frequency responses. Ten parameters were optimized for the design of fourth order discrete time filters numerator and denominator. The Marine Predators method’s results are compared with the results of the Fractional order Darwinian Particle Swarm Optimization (FODPSO) algorithm, from which discrete time filters are obtained for two fractional order continuous time filter models. In this way, it has been shown comparatively that the Marine Predators Algorithm can be used in real engineering problems and can do filter discretization better.
APA, Harvard, Vancouver, ISO, and other styles
2

Coney, William B. "A Procedure for the Comparative Evaluation and Preliminary Design of Marine Propulsors." In SNAME 6th Propeller and Shafting Symposium. SNAME, 1991. http://dx.doi.org/10.5957/pss-1991-07.

Full text
Abstract:
A systematic procedure for the design of a class of marine propulsors is described. This class of propulsors includes traditional propellers, ducted propellers, contra-rotating propellers, vane-wheel propulsors, and propellers operating with pre-or post-swirl stators. The topic of optimum propulsor load distributions is discussed. An algorithm for the determination of optimum radial circulation distributions for this class of propulsors is presented. This algorithm is incorporated in a vortex-lattice, lifting-line model for lightly to moderately loaded marine propulsors. This computer model also incorporates algorithms for the determination of minimum propeller chord lengths and thicknesses, as well as for the determination of optimum values of propeller rpm and diameter. Parametric studies and comparisons of various propulsor configurations can be readily carried out under the described model. A comparative study of marine propulsor alternatives for a given application is presented.
APA, Harvard, Vancouver, ISO, and other styles
3

Yubai, Zhang, Li Qiong, and Tan Shuliang. "Study on Marine Information Model Under Marine Ecological Technology of Computer Cloud Computing." In 2024 IEEE 3rd International Conference on Electrical Engineering, Big Data and Algorithms (EEBDA). IEEE, 2024. http://dx.doi.org/10.1109/eebda60612.2024.10485981.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

SMAOUI, H., C. FLEURY, and L. SCHMIT. "Advances in dual algorithms and convex approximation methods." In Advanced Marine Systems Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1988. http://dx.doi.org/10.2514/6.1988-2382.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Harper, Thurman R., Jeffrey E. Greenblatt, and Andrew J. Mazzeo. "Unattended System for Recording Machinery Transients and for Validation of Trending Algorithms." In Marine Propulsion Technology. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1986. http://dx.doi.org/10.4271/860876.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Kooij, Carmen, Sietske de Geus-Moussault, and Herbert Koelman. "Innovative Maritime Design Education at NHL Stenden University of Applied Sciences." In SNAME 14th International Marine Design Conference. SNAME, 2022. http://dx.doi.org/10.5957/imdc-2022-260.

Full text
Abstract:
To educate ship designers of the future, NHL Stenden University of Applied Sciences aims to continuously innovate education and update the curriculum, for example looking at digitally enabled education. In agreement with this Design Based Education (DBE) has been introduced, a new educational concept. In DBE, students work on projects that are provided by industry partners with core subjects providing the required information to successfully complete the projects. Another endeavour is the introduction of the BSc minor “Advanced Engineering Tools for ShipX”, where X is shorthand for design and operation. This course is concentrated on engineering tools and methods that have emerged in the (construction) industry over the past decades. Because quite some tools are implemented in software, the minor starts with a programming course. However, the emphasis of the minor is not on programming, but on algorithms and algorithmic thinking. For programming languages come and go, while smart algorithms remain to serve us for centuries. Additionally in the BSc, gamification is used to educate an old trade: ship stability. Students experience the primary behaviour of a raft and the forces that act upon it in virtual reality. Afterwards the theory will have to be elaborated a bit more, and the students will have to practice with calculations, but first comes the understanding and only then the math. The master Marine Shipping Innovation focusses on maritime professionals that want to expand their knowledge and learn to innovate. Many students have several years of industry experience and bring with them their expertise and knowledge. A trade they share with their teachers who also combine their teaching job with an additional job in industry. The master offers on demand education, where students can select from a wide range of subjects to further expand their knowledge. At traditional universities, the focus lies on fundamental research, for example, design methods and design tools. Research at universities of applied science is more practical in nature. Engineering in general and the maritime industry specifically is very practical and the application of research is of high interest to the industry. For that reason the major Marine Technology has been selected to run a pilot for a post master applied research program called a Professional Doctorate (PD). The pilot starts in 2022 and currently the implementation of this program is in full swing. In short, this article will discuss the education innovations in both the bachelor and master programs for Marine Technology. It will discuss how the changes are implemented and what the effect is on the education. Finally it will discuss the current steps that are taken to successfully introduce the Professional Doctorate.
APA, Harvard, Vancouver, ISO, and other styles
7

Ruiz-Capel, S., P. Romero-Tello, J. Gutiérrez-Romero, A. Reyes, and D. Kraniotis. "Seakeeping optimization of bulbous bow vessels through genetic algorithms." In 10th Conference on Computational Methods in Marine Engineering. CIMNE, 2023. http://dx.doi.org/10.23967/marine.2023.005.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Xue, Jirai, Weiping Ouyang, Yannan Du, and Huiqing Ouyang. "Simulation Study on Dynamic Characteristic of Marine Elevator." In 2018 International Conference on Mathematics, Modelling, Simulation and Algorithms (MMSA 2018). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/mmsa-18.2018.26.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Taheri, Ramin, and Karim Mazaheri. "Blade Shape Optimization of Marine Propeller via Genetic Algorithm for Efficiency Improvement." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68183.

Full text
Abstract:
In this paper, a numerical optimization method has been carried out to optimize the shape and efficiency of a propeller. For analysis of the hydrodynamic performance parameters, an extended vortex lattice method was used by implementing an open-source code which is called OpenProp. The method of optimization is a non-gradient based algorithm. After a trade-off between a few gradient-based and non-gradient based algorithms, it is found that the problem of being trapped in local optimum solutions can be easily solved by choosing nongradient based ones. Hence, modified Genetic algorithm is used to implement the so-called hydrodynamic performance analyzer code. The objective function is to maximize efficiency by considering the design variables as non-dimensional blade’s chord and thickness distribution along the blade. For initial guess data of the DTRC 4119 propeller which are radially distributed along the blade is used. The hydrodynamic performance analyzer code is modified by a higher order QuasiNewton scheme. Also hybrid function is used to accurate the convergence. Finally, parallel processing implementation on the codes has been done successfully. To improve the computation speed, the algorithm is improved to be extended on a parallel processing system. The process of parallelizing has been done simplicity by Matlab M-code and the number of cores has been chosen as 4. The final results verify both fast convergence in comparison with common methods and nearly 10% improvement in propeller efficiency (mechanical efficiency of the system) which is significant for these kinds of problems. Therefore, the algorithm starts with geometry arrived at by other researchers and improves it to a more efficient propeller.
APA, Harvard, Vancouver, ISO, and other styles
10

Cao, Xiaojuan, and Yongquan Yang. "Research on Chinese Named Entity Recognition in the Marine Field." In ACAI 2018: 2018 International Conference on Algorithms, Computing and Artificial Intelligence. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3302425.3302500.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Algorithmes de mariage"

1

Kularatne, Dhanushka N., Subhrajit Bhattacharya, and M. Ani Hsieh. Computing Energy Optimal Paths in Time-Varying Flows. Drexel University, 2016. http://dx.doi.org/10.17918/d8b66v.

Full text
Abstract:
Autonomous marine vehicles (AMVs) are typically deployed for long periods of time in the ocean to monitor different physical, chemical, and biological processes. Given their limited energy budgets, it makes sense to consider motion plans that leverage the dynamics of the surrounding flow field so as to minimize energy usage for these vehicles. In this paper, we present two graph search based methods to compute energy optimal paths for AMVs in two-dimensional (2-D) time-varying flows. The novelty of the proposed algorithms lies in a unique discrete graph representation of the 3-D configuration space spanned by the spatio-temporal coordinates. This enables a more efficient traversal through the search space, as opposed to a full search of the spatio-temporal configuration space. Furthermore, the proposed strategy results in solutions that are closer to the global optimal when compared to greedy searches through the spatial coordinates alone. We demonstrate the proposed algorithms by computing optimal energy paths around the Channel Islands in the Santa Barbara bay using time-varying flow field forecasts generated by the Regional Ocean Model System. We verify the accuracy of the computed paths by comparing them with paths computed via an optimal control formulation.
APA, Harvard, Vancouver, ISO, and other styles
2

Rémy, Elisabeth, Romain Escudier, and Alexandre Mignot. Access impact of observations. EuroSea, 2023. http://dx.doi.org/10.3289/eurosea_d4.8.

Full text
Abstract:
The accuracy of the Copernicus Marine Environment and Monitoring Service (CMEMS) ocean analysis and forecasts highly depend on the availability and quality of observations to be assimilated. In situ observations are complementary to satellite observations that are restricted to the ocean surface. Higher resolution model forecasts are required by users of the CMEMS global and regional ocean analysis and forecasts. To support this with an efficient observational constrain of the model forecast via data assimilation, an increase observation coverage is needed, associated with an improved usage of the available ocean observations. This work exploits the capabilities of operational systems to provide comprehensive information for the evolution of the GOOS. In this report, we analyse the use and the efficiency of the in-situ observations to constrain regional and global Mercator Ocean systems. Physical and biogeochemical variables are considered. The in-situ observations are used either to estimate physical ocean state at global and regional scale via data assimilation or to estimate BGC model parameters. The impact of the physical in situ observations assimilated in open ocean and coastal areas is assessed with numerical data assimilation experiments. The experiments are conducted with the regional 1/36° resolution and global 1/12° resolution systems operated by Mercator Ocean for the Copernicus Marine Service. For the global physical ocean, the focus is on the tropical ocean to better understand how the tropical mooring observations constrain the intraseasonal to daily variability and the complementarity with satellite observations and the deep ocean. The tropical moorings provide unique high frequency observations at different depth, but they are far away from each other, so part of the signal in the observation are decorrelated from one mooring to the others. It is only via an integrated approach, as data assimilation into a dynamical model and complementarity with other observing networks that those observations can efficiently constrain the different scales of variability of the tropical ocean circulation. As the satellite observations brings higher spatial resolution between the tropical moorings but for the ocean surface, we show that the tropical mooring and Argo profile data assimilation constrain the larger scale ocean thermohaline vertical structure (EuroSea D2.2; Gasparin et al., 2023). The representation of the high frequency signals observed at mooring location is also significantly improved in the model analysis compared to a non-assimilative simulation. The ocean below 2000 m depth is still largely under constrained as very few observations exist. Some deep ocean basins, as the Antarctic deep ocean, shows significant trend over the past decade but they are still not accurately monitored. Based on the spread of four deep ocean reanalysis estimates, large uncertainties were estimated in representing local heat and freshwater content in the deep ocean. Additionally, temperature and salinity field comparison with deep Argo observations demonstrates that reanalysis errors in the deep ocean are of the same size as or even stronger than the observed deep ocean signal. OSSE already suggested that the deployment of a global deep Argo array will significantly constrain the deep ocean in reanalysis to be closer to the observations (Gasparin et al., 2020). At regional and coastal scales, the physical ocean circulation is dominated by higher frequency, smaller scale processes than the open ocean which requires different observation strategy to be well monitor. The impact of assimilating high frequency and high-resolution observations provided by gliders on European shelves is analysed with the regional Iberic Biscay and Irish (IBI) system. It was found that repetitive glider sections can efficiently help to constrain the transport of water masses flowing across those sections. BGC ocean models are less mature than physical ocean models and some variable dependencies are still based on empirical functions. In this task, Argo BGC profile observations were used to optimize the parameters of the global CMEMS biogeochemical model, PISCES. A particle filter algorithm was chosen to optimize a 1D configuration of PISCES in the North Atlantic. The optimization of the PISCES 1D model significantly improves the model's ability to reproduce the North Atlantic bloom Recommendations on the in-situ network extensions for real time ocean monitoring are given based on those results, and the one also obtained in the WP2, Task 2.2 where data assimilation experiments but with simulated observations where conducted. Argo extension and the complementarity with satellite altimetry was also extensively studied. (EuroSea Deliverable ; D4.8)
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography