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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Function Block Algorithms for Adaptive Robotic Control

Egaña Iztueta, Lander, Roda Martínez, Javier January 2014 (has links)
The purpose of this project is the creation of an adaptive Function Block control system, and the implementation of Artificial Intelligence integrated within the Function Block control system, using IEC 61499 standard to control an ABB 6-axis virtual robot, simulated in the software RobotStudio. To develop these objectives, we studied a lot of necessary concepts and how to use three different softwares. To learn how to use the softwares, some tests were carried out. RobotStudio is a program developed by ABB Robotics Company where an ABB robot and a station are simulated. There, we designed and created a virtual assembly cell with the virtual IRB140 robot and the necessary pieces to simulate the system. To control the robot and the direct access to the different tools of RobotStudio, it is necessary to use an application programming interface (API) developed by ABB Robotics Company. C sharp (C#) language is used to program using the API, but this language is not supported by the Function Block programming software nxtStudio. Because of this, we used VisualStudio software. In this software, we use the API libraries to start and stop the robot and load a RAPID file in the controller. In a RAPID file the instructions that the robot must follow are written. So, we had to learn about how to program in C# language and how to use VisualStudio software. Also, to learn about IEC 61499 standard it was necessary to read some books. This standard determines how an application should be programmed through function blocks. A function block is a unit of program with a certain functionality which contains data and variables that can be manipulated in the same function block by several algorithms. To program in this standard we learnt how to use nxtStudio software, consuming a lot of time because the program is quite complex and it is not much used in the industrial world yet. Some tests were performed to learn different programing skills in this standard, such as how to use UDP communication protocol and how to program interfaces. Learning UDP communication was really useful because it is necessary for communication between nxtStudio and other programs, and also learning how to use interfaces to let the user access the program. Once we had learnt about how to use and program the different softwares and languages, we began to program the project. Then, we had some troubles with nxtStudio because strings longer than fourteen characters cannot be used here. So, a motion alarm was developed in VisualStudio program. And another important limitation of nxtStudio is that C++ language cannot be used. Therefore, the creation of an Artificial Intelligence system was not possible. So, we created a Function Block control system. This system is a logistical system realised through loops, conditions and counters. All this makes the robot more adaptive. As the AI could not be carried out because of the different limitations, we theoretically designed the AI system. It will be possible to implement the AI when the limitations and the problems are solved.
2

Towards a high performance parallel library to compute fluid flexible structures interactions

Nagar, Prateek 08 April 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / LBM-IB method is useful and popular simulation technique that is adopted ubiquitously to solve Fluid-Structure interaction problems in computational fluid dynamics. These problems are known for utilizing computing resources intensively while solving mathematical equations involved in simulations. Problems involving such interactions are omnipresent, therefore, it is eminent that a faster and accurate algorithm exists for solving these equations, to reproduce a real-life model of such complex analytical problems in a shorter time period. LBM-IB being inherently parallel, proves to be an ideal candidate for developing a parallel software. This research focuses on developing a parallel software library, LBM-IB based on the algorithm proposed by [1] which is first of its kind that utilizes the high performance computing abilities of supercomputers procurable today. An initial sequential version of LBM-IB is developed that is used as a benchmark for correctness and performance evaluation of shared memory parallel versions. Two shared memory parallel versions of LBM-IB have been developed using OpenMP and Pthread library respectively. The OpenMP version is able to scale well enough, as good as 83% speedup on multicore machines for <=8 cores. Based on the profiling and instrumentation done on this version, to improve the data-locality and increase the degree of parallelism, Pthread based data centric version is developed which is able to outperform the OpenMP version by 53% on manycore machines. A distributed version using the MPI interfaces on top of the cube based Pthread version has also been designed to be used by extreme scale distributed memory manycore systems.
3

Séparation aveugle de mélanges linéaires de sources : application à la surveillance maritime / Blind sources separation : application to marine surveillance

Cherrak, Omar 19 March 2016 (has links)
Dans cette thèse, nous nous intéressons au système d’identification automatique spatial lequel est dédié à la surveillancemaritime par satellite. Ce système couvre une zone bien plus large que le système standard à terre correspondant àplusieurs cellules traditionnelles ce qui peut entraîner des risques de collision des données envoyées par des navireslocalisés dans des cellules différentes et reçues au niveau de l’antenne du satellite. Nous présentons différentes approchesafin de répondre au problème de collision considéré. Elles ne reposent pas toujours sur les mêmes hypothèses en ce quiconcerne les signaux reçus, et ne s’appliquent donc pas toutes dans les mêmes contextes (nombre de capteurs utilisés,mode semi-supervisé avec utilisation de trames d’apprentissage et information a priori ou mode aveugle, problèmes liés àla synchronisation des signaux, etc...).Dans un premier temps, nous proposons des méthodes permettant la séparation/dé-collision des messages en modèle surdéterminé(plus de capteurs que de messages). Elles sont fondées sur des algorithmes de décompositions matriciellesconjointes combinés à des détecteurs de points temps-fréquence (retard-fréquence Doppler) particuliers permettant laconstruction d’ensembles de matrices devant être (bloc) ou zéro (bloc) diagonalisées conjointement. En ce qui concerneles algorithmes de décompositions matricielles conjointes, nous proposons quatre nouveaux algorithmes de blocdiagonalisation conjointe (de même que leur version à pas optimal) fondés respectivement sur des algorithmesd’optimisation de type gradient conjugué, gradient conjugué pré-conditionné, Levenberg-Marquardt et Quasi-Newton. Lecalcul exact du gradient matriciel complexe et des matrices Hessiennes complexes est mené. Nous introduisonségalement un nouveau problème dénommé zéro-bloc diagonalisation conjointe non-unitaire lequel généralise le problèmedésormais classique de la zéro-diagonalisation conjointe non-unitaire. Il implique le choix d’une fonction de coût adaptéeet à nouveau le calcul de quantités telles que gradient matriciel complexe et les matrices Hessiennes complexes. Nousproposons ensuite trois nouveaux algorithmes à pas optimal fondés sur des algorithmes d’optimisation de type gradientconjugué, gradient conjugué pré-conditionné et Levenberg-Marquardt.Finalement, nous terminons par des approches à base de techniques de détection multi-utilisateurs conjointe susceptiblesde fonctionner en contexte sous-déterminé dans lequel nous ne disposons plus que d’un seul capteur recevantsimultanément plusieurs signaux sources. Nous commençons par développer une première approche par déflationconsistant à supprimer successivement les interférences. Nous proposons ensuite un deuxième mode opératoire fondéquant à lui sur l’estimateur du maximum de vraisemblance conjoint qui est une variante de l’algorithme de VITERBI. / This PHD thesis concerns the spatial automatic identification system dedicated to marine surveillance by satellite. Thissystem covers a larger area than the traditional system corresponding to several satellite cells. In such a system, there arerisks of collision of the messages sent by vessels located in different cells and received at the antenna of the samesatellite. We present different approaches to address the considered problem. They are not always based on the sameassumptions regarding the received signals and are not all applied in the same contexts (they depend on the number ofused sensors, semi-supervised mode with use of training sequences and a priori information versus blind mode, problemswith synchronization of signals, etc.). Firstly, we develop several approaches for the source separation/de-collision in theover-determined case (more sensors than messages) using joint matrix decomposition algorithms combined withdetectors of particular time-frequency (delay-Doppler frequency) points to build matrix sets to be joint (block) or zero(block) diagonalized. Concerning joint matrix decomposition algorithms, four new joint block-diagonalization algorithms(with optimal step-size) are introduced based respectively on conjugate gradient, preconditioned conjugate gradient,Levenberg-Marquardt and Quasi-Newton optimization schemes. Secondly, a new problem called non-unitary joint zeroblockdiagonalization is introduced. It encompasses the classical joint zero diagonalization problem. It involves thechoice of a well-chosen cost function and the calculation of quantities such as the complex gradient matrix and thecomplex Hessian matrices. We have therefore proposed three new algorithms (and their optimal step-size version) basedrespectively on conjugate gradient, preconditioned conjugate gradient and Levenberg-Marquardt optimization schemes.Finally, we suggest other approaches based on multi-user joint detection techniques in an underdetermined context wherewe have only one sensor receiving simultaneously several signals. First, we have developed an approach by deflationbased on a successive interferences cancelation technique. Then, we have proposed a second method based on the jointmaximum likelihood sequence estimator which is a variant of the VITERBI algorithm.

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