Конечно-разностная миграция в трехмерном варианте с распараллеливанием процесса вычислений

Переход сейсморазведки на трехмерные или площадные системы наблюдений ведет к значительному увеличению объема зарегистрированных волновых полей, которые необходимо обработать в кратчайшие сроки. При этом необходимо учитывать постоянно возрастающие требования к детальности результата и сложность строения изучаемой площади. В то же время, несмотря на быстрый прогресс в области развития вычислительной техники, появляется проблема недостаточности ресурсов для обработки трехмерных сейсмических наблюдений на отдельно взятом компьютере. Поэтому задача программной реализации существующих процедур обработки с привлечением кластера становится чрезвычайно актуальной в современной сейсморазведке. Рассмотрены разработанные алгоритм и программная реализация трехмерной конечно-разностной миграции после суммы с распараллеливанием процесса вычислений.Перехід сейсморозвідки на тривимірні або площові системи спостережень приводить до значного збільшення обсягу зареєстрованих хвильових полів, які необхідно обробити у найкоротші терміни. При цьому потрібно враховувати постійно зростаючі вимоги до детальності результату і складність будови досліджуваної площі. Водночас, незважаючи на швидкий прогрес у сфері розвитку обчислювальної техніки, з’являється проблема недостатності ресурсів для обробки тривимірних сейсмічних спостережень на окремо взятому комп’ютері. Тому задача програмної реалізації існуючих процедур обробки із залученням кластера стає надзвичайно актуальною в сучасній сейсморозвідці. Розглянуто розроблені алгоритм і програмну реалізацію тривимірної скінченнорізницевої міграції після суми з розпаралелюванням процесу обчислень.The purpose of the paper is to develop a three-dimensional post stack finite-difference migration with parallelization of computing process to process 3D seismic observations on a separate computer, taking into account the ever-increasing requirements for detailed results and the complexity of the structure of the study area. The effectiveness of the developed version of the post stack finite-difference migration is proved with practical examples, in particular, for the structure of medium complicated by the presence of the salt body. Design/methodology/approach. Algorithm of a three-dimensional post stack migration is based on reverse full-wave field continuation in the medium that is carried out by solving the differential wave equation using a finite difference method. In this case the differential wave equation is approximated by the difference one in the four-dimensional space-time grid. In this approach, the coordinate system is converted according to the seismic wave propagation from the depths to the surface, ensuring optimal finite-difference wave field continuation. Parallelization of computations process is on time slices which are defined with a queue. The calculation of the previous slice is stored in the intermediate memory cube. In parallelizing we used library pthread, which is present in all modern versions of the Linux system and allows you to control the execution of the task in the separation calculations on several processors. The software was developed according to the proposed algorithm of a three-dimensional post stack finite-difference migration with parallelization of the computing process for processing. Findings. The developed three-dimensional post stack full-wave finite-difference migration with parallelization of computing process for processing has been tested in a model and real mode. The obtained results confirm the applicability of the developed method of migration in studding the geological environment of deep structure with different degrees of complexity. To demonstrate the effectiveness of this method we compared the results obtained with those obtained using standard software migration system ProMAX and the developed program with parallelization of computing process on the cluster, developed at the Institute of Geophysics. The comparison of the results allows us to emphasize a general similarity of the results and the difference in some of the particular parts of the image (larger extension of reflecting horizons in the direction of the salt body as a result of applying the proposed variant of post stack full-wave finite-difference migration), which may be attributed to a more accurate migration transformation in the developed program. Practical value/implications. The developed version of a three-dimensional post stack full-wave finite-difference migration with parallelization of computing process allows on to carry out high-quality processing of large volumes of spatial seismic data in a short time, which depend on the number of processors in the cluster. The results of the testing of developed programs as in model and real data areal seismic survey, prove accuracy and efficiency even in the structure of the medium complicated by the presence of salt body, which is important for oil and gas companies, exploration activities

Uma abordagem de consciência de máquina ao controle de semáforos de tráfego urbano

Orientador: Ricardo Ribeiro GudwinTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Neste trabalho, apresentamos uma arquitetura cognitiva distribuída usada para o controle de tráfego em uma rede urbana. Essa arquitetura se baseia em uma abordagem de consciência de máquina - Teoria do Workspace Global - de forma a usar competição e difusão em broadcast, permitindo que um grupo de controladores de tráfego locais interajam, resultando em melhor desempenho do grupo. A ideia principal é que controladores locais geralmente realizam um comportamento reativo, definindo os tempos de verde e vermelho do semáforo, de acordo com informações locais. Esses controladores locais competem de forma a definir qual deles está experienciando a situação mais crítica. O controlador nas piores condições ganha acesso ao workspace global, e depois realiza uma difusão em broadcast de sua condição (e sua localização) para todos os outros controladores, pedindo sua ajuda para lidar com sua situação. Essa chamada do controlador que acessa o workspace global causará uma interferência no comportamento local reativo, para aqueles controladores locais com alguma chance de ajudar o controlador na situação crítica, contendo o tráfego na sua direção. Esse comportamento do grupo, coordenado pela estratégia do workspace global, transforma o comportamento reativo anterior em uma forma de comportamento deliberativo. Nós mostramos que essa estratégia é capaz de melhorar a média do tempo de viagem de todos os veículos que fluem na rede urbana. Um ganho consistente no desempenho foi conseguido com o controlador "Consciência de Máquina" durante todo o tempo da simulação, em diferentes cenários, indo de 10% até maisde 20%, quando comparado ao controlador "Reativo Paralelo" sem o mecanismo de consciência artificial, produzindo evidência para suportar a hipótese de que um mecanismo de consciência artificial, que difunde serialmente em broadcast conteúdo para processos automáticos, pode trazer vantagens para uma tarefa global realizada por uma sociedade de agentes paralelos que operam juntos por uma meta comumAbstract: In this work, we present a distributed cognitive architecture used to control the traffic in an urban network. This architecture relies on a machine consciousness approach - Global Workspace Theory - in order to use competition and broadcast, allowing a group of local traffic controllers to interact, resulting in a better group performance.The main idea is that the local controllers usually perform a purely reactive behavior, defining the times of red and green lights, according just to local information. These local controllers compete in order to define which of them is experiencing the most critical traffic situation. The controller in the worst condition gains access to the global workspace, further broadcasting its condition (and its location) to all other controllers, asking for their help in dealing with its situation. This call from the controller accessing the global workspace will cause an interference in the reactive local behavior, for those local controllers with some chance in helping the controller in a critical condition, by containing traffic in its direction. This group behavior, coordinated by the global workspace strategy, turns the once reactive behavior into a kind of deliberative one. We show that this strategy is capable of improving the overall mean travel time of vehicles flowing through the urban network. A consistent gain in performance with the "Machine Consciousness" traffic signal controller during all simulation time, throughout different simulated scenarios, could be observed, ranging from around 10% to more than 20%, when compared to the "Parallel Reactive" controller without the artificial consciousness mechanism, producing evidence to support the hypothesis that an artificial consciousness mechanism, which serially broadcasts content to automatic processes, can bring advantages to the global task performed by a society of parallel agents working together for a common goalDoutoradoEngenharia de ComputaçãoDoutor em Engenharia Elétrica153206/2010-1CNPQCAPESFAPES