The Experts below are selected from a list of 11094 Experts worldwide ranked by ideXlab platform
Dmytro Korzhyk - One of the best experts on this subject based on the ideXlab platform.
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Catcher evader games
International Joint Conference on Artificial Intelligence, 2016Co-Authors: Yuqian Li, Vincent Conitzer, Dmytro KorzhykAbstract:Algorithms for computing game-theoretic solutions have recently been applied to a number of security domains. However, many of the techniques developed for compact representations of security games do not extend to Bayesian security games, which allow us to model uncertainty about the attacker's type. In this paper, we introduce a general framework of Catcher-evader games that can capture Bayesian security games as well as other game families of interest. We show that computing Stackelberg strategies is NP-hard, but give an algorithm for computing a Nash equilibrium that performs well in experiments. We also prove that the Nash equilibria of these games satisfy the interchangeability property, so that equilibrium selection is not an issue.
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Catcher evader games
arXiv: Computer Science and Game Theory, 2016Co-Authors: Yuqian Li, Vincent Conitzer, Dmytro KorzhykAbstract:Algorithms for computing game-theoretic solutions have recently been applied to a number of security domains. However, many of the techniques developed for compact representations of security games do not extend to {\em Bayesian} security games, which allow us to model uncertainty about the attacker's type. In this paper, we introduce a general framework of {\em Catcher-evader} games that can capture Bayesian security games as well as other game families of interest. We show that computing Stackelberg strategies is NP-hard, but give an algorithm for computing a Nash equilibrium that performs well in experiments. We also prove that the Nash equilibria of these games satisfy the {\em interchangeability} property, so that equilibrium selection is not an issue.
Eli Brenner - One of the best experts on this subject based on the ideXlab platform.
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Flexible timing of eye movements when catching a ball.
Journal of vision, 2016Co-Authors: Joan López-moliner, Eli BrennerAbstract:In ball games, one cannot direct ones gaze at the ball all the time because one must also judge other aspects of the game, such as other players' positions. We wanted to know whether there are times at which obtaining information about the ball is particularly beneficial for catching it. We recently found that people could catch successfully if they saw any part of the ball's flight except the very end, when sensory-motor delays make it impossible to use new information. Nevertheless, there may be a preferred time to see the ball. We examined when six Catchers would choose to look at the ball if they had to both catch the ball and find out what to do with it while the ball was approaching. A Catcher and a thrower continuously threw a ball back and forth. We recorded their hand movements, the Catcher's eye movements, and the ball's path. While the ball was approaching the Catcher, information was provided on a screen about how the Catcher should throw the ball back to the thrower (its peak height). This information disappeared just before the Catcher caught the ball. Initially there was a slight tendency to look at the ball before looking at the screen but, later, most Catchers tended to look at the screen before looking at the ball. Rather than being particularly eager to see the ball at a certain time, people appear to adjust their eye movements to the combined requirements of the task.
Yuqian Li - One of the best experts on this subject based on the ideXlab platform.
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Catcher evader games
International Joint Conference on Artificial Intelligence, 2016Co-Authors: Yuqian Li, Vincent Conitzer, Dmytro KorzhykAbstract:Algorithms for computing game-theoretic solutions have recently been applied to a number of security domains. However, many of the techniques developed for compact representations of security games do not extend to Bayesian security games, which allow us to model uncertainty about the attacker's type. In this paper, we introduce a general framework of Catcher-evader games that can capture Bayesian security games as well as other game families of interest. We show that computing Stackelberg strategies is NP-hard, but give an algorithm for computing a Nash equilibrium that performs well in experiments. We also prove that the Nash equilibria of these games satisfy the interchangeability property, so that equilibrium selection is not an issue.
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Catcher evader games
arXiv: Computer Science and Game Theory, 2016Co-Authors: Yuqian Li, Vincent Conitzer, Dmytro KorzhykAbstract:Algorithms for computing game-theoretic solutions have recently been applied to a number of security domains. However, many of the techniques developed for compact representations of security games do not extend to {\em Bayesian} security games, which allow us to model uncertainty about the attacker's type. In this paper, we introduce a general framework of {\em Catcher-evader} games that can capture Bayesian security games as well as other game families of interest. We show that computing Stackelberg strategies is NP-hard, but give an algorithm for computing a Nash equilibrium that performs well in experiments. We also prove that the Nash equilibria of these games satisfy the {\em interchangeability} property, so that equilibrium selection is not an issue.
Ruholla Azizian - One of the best experts on this subject based on the ideXlab platform.
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two sided wind Catcher performance evaluation using experimental numerical and analytical modeling
Renewable Energy, 2010Co-Authors: H Montazeri, Ruholla Azizian, Fatemeh Montazeri, Shima MostafaviAbstract:Experimental wind tunnel and smoke visualization testing as well as CFD and analytical modeling were conducted to investigate the performance of a two-sided wind Catcher. This type of wind Catcher is divided internally into two halves for the purposes of air supply and extract. In this study, the two-sided wind Catcher model was constructed of two similar one-sided wind Catcher models, which were attached together back to back. These one-sided models are 1:40 scale models of Kharmani's School wind Catcher in the city of Yazd. Experimental investigations were carried out using an open-circuit wind tunnel and both the induced volumetric airflow into the building and the pressure coefficients around all surfaces of the wind Catcher model were measured at various wind angles. Furthermore, the CFD simulation was also used to evaluate the pressure coefficient distribution and airflow pattern around and through the wind Catcher. Additional experimental tests and computational fluid dynamics simulation of the wind Catcher in the wind tunnel were also conducted in order to assess the accuracy of measurement procedures and the uncertainty of experimental results. This article also represents a semi-empirical approach in which experimental data were used for a detailed analytic model, in order to provide an accurate estimate of the performance of wind Catchers. It was found that for an isolated two-sided wind Catcher model, the maximum efficiency is achieved at the angle of 90°. At this air incident angle the wind Catcher efficiency increases approximately 20% more than the one at zero angle. The experimental investigations demonstrated the potential of two-sided wind Catcher for enhancing the natural ventilation inside buildings. It can be seen that CFD simulation and analytical modeling results have a good agreement with the experimental results. Theoretical modeling can also help to assess the accuracy of measurement procedures and the uncertainty of experimental results.
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Experimental study on natural ventilation performance of a two-sided wind Catcher
Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2009Co-Authors: H Montazeri, Ruholla AzizianAbstract:AbstractExperimental wind tunnel and smoke visualization testing was conducted to investigate the performance of a two-sided wind Catcher. This type of wind Catcher is divided internally into two halves for the purposes of air supply and extract. In this study, the two-sided wind Catcher model was constructed of two similar one-sided wind Catcher models, which were attached back to back. These one-sided models are 1: 40 scale models of Kharmani's School wind Catcher in the city of Yazd. Experimental investigations were carried out using an open-circuit wind tunnel, and both the induced volumetric airflow into the building and the pressure coefficients around all surfaces of the wind Catcher model were measured at various wind angles. Additional experimental tests and computational fluid dynamics simulation of the wind Catcher in the wind tunnel were also conducted in order to assess the accuracy of measurement procedures and the uncertainty of experimental results. To evaluate the stack effects on the nat...
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experimental study on natural ventilation performance of one sided wind Catcher
Building and Environment, 2008Co-Authors: H Montazeri, Ruholla AzizianAbstract:Hydrodynamic performance of a one-sided wind Catcher was investigated by experimental wind tunnel and smoke visualization testing. Wind Catchers or what is called Baud-Geers in Persian language was a main component of buildings in central region of Iran and the neighboring countries. A Baud-Geer is a tower used to capture wind from external air stream and induce it into the building in order to provide natural ventilation and passive cooling. Due to geographical coordinates of the region, wind power and the direction of blowing wind, wind Catchers are employed in different heights, cross sections of the air passages and the places and the number of the openings. The one-sided wind Catcher has only one channel as a passage of induced air and is often related to the areas where there is prevailing wind. These Baud-Geers are employed to catch the wind blowing at higher elevations and direct it to the building, causing it to leave through windows, doors or other exhausted segments. In this study a 1:40 scale model of Kharmani's School Baud-Geer was employed and the induced air flow rate into the test room and the pressure coefficients around all surfaces of its channel were measured for different values of approaching air incident angles. Using measured pressure coefficients, the theoretical values of ventilation air flow were estimated to evaluate ability of simplified models in natural ventilation studies. Due to placing of urban full-scale wind Catchers in the boundary layer of atmospheric winds, the effect of this phenomenon was also examined. The experiments were conducted when the wind Catcher model with adjoining house was placed in the wake of upstream objects, resembling neighboring buildings. It was found that for an isolated wind Catcher model, the maximum efficiency is achieved at zero air incident angle. Also it was concluded that the angle of incidence of the wind, the presence of an upstream building around the structure and blowing of atmospheric wind influence the pressure coefficients, the rate and the direction of ventilation air flow.
H Montazeri - One of the best experts on this subject based on the ideXlab platform.
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two sided wind Catcher performance evaluation using experimental numerical and analytical modeling
Renewable Energy, 2010Co-Authors: H Montazeri, Ruholla Azizian, Fatemeh Montazeri, Shima MostafaviAbstract:Experimental wind tunnel and smoke visualization testing as well as CFD and analytical modeling were conducted to investigate the performance of a two-sided wind Catcher. This type of wind Catcher is divided internally into two halves for the purposes of air supply and extract. In this study, the two-sided wind Catcher model was constructed of two similar one-sided wind Catcher models, which were attached together back to back. These one-sided models are 1:40 scale models of Kharmani's School wind Catcher in the city of Yazd. Experimental investigations were carried out using an open-circuit wind tunnel and both the induced volumetric airflow into the building and the pressure coefficients around all surfaces of the wind Catcher model were measured at various wind angles. Furthermore, the CFD simulation was also used to evaluate the pressure coefficient distribution and airflow pattern around and through the wind Catcher. Additional experimental tests and computational fluid dynamics simulation of the wind Catcher in the wind tunnel were also conducted in order to assess the accuracy of measurement procedures and the uncertainty of experimental results. This article also represents a semi-empirical approach in which experimental data were used for a detailed analytic model, in order to provide an accurate estimate of the performance of wind Catchers. It was found that for an isolated two-sided wind Catcher model, the maximum efficiency is achieved at the angle of 90°. At this air incident angle the wind Catcher efficiency increases approximately 20% more than the one at zero angle. The experimental investigations demonstrated the potential of two-sided wind Catcher for enhancing the natural ventilation inside buildings. It can be seen that CFD simulation and analytical modeling results have a good agreement with the experimental results. Theoretical modeling can also help to assess the accuracy of measurement procedures and the uncertainty of experimental results.
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Experimental study on natural ventilation performance of a two-sided wind Catcher
Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2009Co-Authors: H Montazeri, Ruholla AzizianAbstract:AbstractExperimental wind tunnel and smoke visualization testing was conducted to investigate the performance of a two-sided wind Catcher. This type of wind Catcher is divided internally into two halves for the purposes of air supply and extract. In this study, the two-sided wind Catcher model was constructed of two similar one-sided wind Catcher models, which were attached back to back. These one-sided models are 1: 40 scale models of Kharmani's School wind Catcher in the city of Yazd. Experimental investigations were carried out using an open-circuit wind tunnel, and both the induced volumetric airflow into the building and the pressure coefficients around all surfaces of the wind Catcher model were measured at various wind angles. Additional experimental tests and computational fluid dynamics simulation of the wind Catcher in the wind tunnel were also conducted in order to assess the accuracy of measurement procedures and the uncertainty of experimental results. To evaluate the stack effects on the nat...
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experimental study on natural ventilation performance of one sided wind Catcher
Building and Environment, 2008Co-Authors: H Montazeri, Ruholla AzizianAbstract:Hydrodynamic performance of a one-sided wind Catcher was investigated by experimental wind tunnel and smoke visualization testing. Wind Catchers or what is called Baud-Geers in Persian language was a main component of buildings in central region of Iran and the neighboring countries. A Baud-Geer is a tower used to capture wind from external air stream and induce it into the building in order to provide natural ventilation and passive cooling. Due to geographical coordinates of the region, wind power and the direction of blowing wind, wind Catchers are employed in different heights, cross sections of the air passages and the places and the number of the openings. The one-sided wind Catcher has only one channel as a passage of induced air and is often related to the areas where there is prevailing wind. These Baud-Geers are employed to catch the wind blowing at higher elevations and direct it to the building, causing it to leave through windows, doors or other exhausted segments. In this study a 1:40 scale model of Kharmani's School Baud-Geer was employed and the induced air flow rate into the test room and the pressure coefficients around all surfaces of its channel were measured for different values of approaching air incident angles. Using measured pressure coefficients, the theoretical values of ventilation air flow were estimated to evaluate ability of simplified models in natural ventilation studies. Due to placing of urban full-scale wind Catchers in the boundary layer of atmospheric winds, the effect of this phenomenon was also examined. The experiments were conducted when the wind Catcher model with adjoining house was placed in the wake of upstream objects, resembling neighboring buildings. It was found that for an isolated wind Catcher model, the maximum efficiency is achieved at zero air incident angle. Also it was concluded that the angle of incidence of the wind, the presence of an upstream building around the structure and blowing of atmospheric wind influence the pressure coefficients, the rate and the direction of ventilation air flow.