WorldWideScience

Sample records for stochastic pursuit-evasion games

  1. Contributions to Pursuit-Evasion Game Theory

    Science.gov (United States)

    Oyler, Dave Wilson

    This dissertation studies adversarial conflicts among a group of agents moving in the plane, possibly among obstacles, where some agents are pursuers and others are evaders. The goal of the pursuers is to capture the evaders, where capture requires a pursuer to be either co-located with an evader, or in close proximity. The goal of the evaders is to avoid capture. These scenarios, where different groups compete to accomplish conflicting goals, are referred to as pursuit-evasion games, and the agents are called players. Games featuring one pursuer and one evader are analyzed using dominance, where a point in the plane is said to be dominated by a player if that player is able to reach the point before the opposing players, regardless of the opposing players' actions. Two generalizations of the Apollonius circle are provided. One solves games with environments containing obstacles, and the other provides an alternative solution method for the Homicidal Chauffeur game. Optimal pursuit and evasion strategies based on dominance are provided. One benefit of dominance analysis is that it extends to games with many players. Two foundational games are studied; one features multiple pursuers against a single evader, and the other features a single pursuer against multiple evaders. Both are solved using dominance through a reduction to single pursuer, single evader games. Another game featuring competing teams of pursuers is introduced, where an evader cooperates with friendly pursuers to rendezvous before being captured by adversaries. Next, the assumption of complete and perfect information is relaxed, and uncertainties in player speeds, player positions, obstacle locations, and cost functions are studied. The sensitivity of the dominance boundary to perturbations in parameters is provided, and probabilistic dominance is introduced. The effect of information is studied by comparing solutions of games with perfect information to games with uncertainty. Finally, a pursuit law

  2. Pursuit-evasion differential games

    CERN Document Server

    Yavin, Y

    1987-01-01

    Twenty papers are devoted to the treatment of a wide spectrum of problems in the theory and applications of dynamic games with the emphasis on pursuit-evasion differential games. The problem of capturability is thoroughly investigated, also the problem of noise-corrupted (state) measurements. Attention is given to aerial combat problems and their attendant modelling issues, such as variable speed of the combatants, the three-dimensionality of physical space, and the combat problem, i.e. problems related to 'role determination'.

  3. Simple Motion Pursuit and Evasion Differential Games with Many Pursuers on Manifolds with Euclidean Metric

    Directory of Open Access Journals (Sweden)

    Atamurat Kuchkarov

    2016-01-01

    Full Text Available We consider pursuit and evasion differential games of a group of m pursuers and one evader on manifolds with Euclidean metric. The motions of all players are simple, and maximal speeds of all players are equal. If the state of a pursuer coincides with that of the evader at some time, we say that pursuit is completed. We establish that each of the differential games (pursuit or evasion is equivalent to a differential game of m groups of countably many pursuers and one group of countably many evaders in Euclidean space. All the players in any of these groups are controlled by one controlled parameter. We find a condition under which pursuit can be completed, and if this condition is not satisfied, then evasion is possible. We construct strategies for the pursuers in pursuit game which ensure completion the game for a finite time and give a formula for this time. In the case of evasion game, we construct a strategy for the evader.

  4. Multiagent pursuit-evasion games: Algorithms and experiments

    Science.gov (United States)

    Kim, Hyounjin

    Deployment of intelligent agents has been made possible through advances in control software, microprocessors, sensor/actuator technology, communication technology, and artificial intelligence. Intelligent agents now play important roles in many applications where human operation is too dangerous or inefficient. There is little doubt that the world of the future will be filled with intelligent robotic agents employed to autonomously perform tasks, or embedded in systems all around us, extending our capabilities to perceive, reason and act, and replacing human efforts. There are numerous real-world applications in which a single autonomous agent is not suitable and multiple agents are required. However, after years of active research in multi-agent systems, current technology is still far from achieving many of these real-world applications. Here, we consider the problem of deploying a team of unmanned ground vehicles (UGV) and unmanned aerial vehicles (UAV) to pursue a second team of UGV evaders while concurrently building a map in an unknown environment. This pursuit-evasion game encompasses many of the challenging issues that arise in operations using intelligent multi-agent systems. We cast the problem in a probabilistic game theoretic framework and consider two computationally feasible pursuit policies: greedy and global-max. We also formulate this probabilistic pursuit-evasion game as a partially observable Markov decision process and employ a policy search algorithm to obtain a good pursuit policy from a restricted class of policies. The estimated value of this policy is guaranteed to be uniformly close to the optimal value in the given policy class under mild conditions. To implement this scenario on real UAVs and UGVs, we propose a distributed hierarchical hybrid system architecture which emphasizes the autonomy of each agent yet allows for coordinated team efforts. We then describe our implementation on a fleet of UGVs and UAVs, detailing components such

  5. Multiagent Cooperative Learning Strategies for Pursuit-Evasion Games

    Directory of Open Access Journals (Sweden)

    Jong Yih Kuo

    2015-01-01

    Full Text Available This study examines the pursuit-evasion problem for coordinating multiple robotic pursuers to locate and track a nonadversarial mobile evader in a dynamic environment. Two kinds of pursuit strategies are proposed, one for agents that cooperate with each other and the other for agents that operate independently. This work further employs the probabilistic theory to analyze the uncertain state information about the pursuers and the evaders and uses case-based reasoning to equip agents with memories and learning abilities. According to the concepts of assimilation and accommodation, both positive-angle and bevel-angle strategies are developed to assist agents in adapting to their environment effectively. The case study analysis uses the Recursive Porous Agent Simulation Toolkit (REPAST to implement a multiagent system and demonstrates superior performance of the proposed approaches to the pursuit-evasion game.

  6. Aspects of random geometric graphs : Pursuit-evasion and treewidth

    NARCIS (Netherlands)

    Li, A.

    2015-01-01

    In this thesis, we studied two aspects of random geometric graphs: pursuit-evasion and treewidth. We first studied one pursuit-evasion game: Cops and Robbers. This game, which dates back to 1970s, are studied extensively in recent years. We investigate this game on random geometric graphs, and get

  7. Fixed Duration Pursuit-Evasion Differential Game with Integral Constraints

    International Nuclear Information System (INIS)

    Ibragimov G I; Kuchkarov A Sh

    2013-01-01

    We investigate a pursuit-evasion differential game of countably many pursuers and one evader. Integral constraints are imposed on control functions of the players. Duration of the game is fixed and the payoff of the game is infimum of the distances between the evader and pursuers when the game is completed. Purpose of the pursuers is to minimize the payoff and that of the evader is to maximize it. Optimal strategies of the players are constructed, and the value of the game is found. It should be noted that energy resource of any pursuer may be less than that of the evader.

  8. On Some Pursuit and Evasion Differential Game Problems for an Infinite Number of First-Order Differential Equations

    Directory of Open Access Journals (Sweden)

    Abbas Badakaya Ja'afaru

    2012-01-01

    Full Text Available We study pursuit and evasion differential game problems described by infinite number of first-order differential equations with function coefficients in Hilbert space l2. Problems involving integral, geometric, and mix constraints to the control functions of the players are considered. In each case, we give sufficient conditions for completion of pursuit and for which evasion is possible. Consequently, strategy of the pursuer and control function of the evader are constructed in an explicit form for every problem considered.

  9. An orbital emulator for pursuit-evasion game theoretic sensor management

    Science.gov (United States)

    Shen, Dan; Wang, Tao; Wang, Gang; Jia, Bin; Wang, Zhonghai; Chen, Genshe; Blasch, Erik; Pham, Khanh

    2017-05-01

    This paper develops and evaluates an orbital emulator (OE) for space situational awareness (SSA). The OE can produce 3D satellite movements using capabilities generated from omni-wheeled robot and robotic arm motion methods. The 3D motion of a satellite is partitioned into the movements in the equatorial plane and the up-down motions in the vertical plane. The 3D actions are emulated by omni-wheeled robot models while the up-down motions are performed by a stepped-motor-controlled-ball along a rod (robotic arm), which is attached to the robot. For multiple satellites, a fast map-merging algorithm is integrated into the robot operating system (ROS) and simultaneous localization and mapping (SLAM) routines to locate the multiple robots in the scene. The OE is used to demonstrate a pursuit-evasion (PE) game theoretic sensor management algorithm, which models conflicts between a space-based-visible (SBV) satellite (as pursuer) and a geosynchronous (GEO) satellite (as evader). The cost function of the PE game is based on the informational entropy of the SBV-tracking-GEO scenario. GEO can maneuver using a continuous and low thruster. The hard-in-loop space emulator visually illustrates the SSA problem solution based PE game.

  10. Rotorcraft pursuit-evasion in nap-of-the-earth flight

    Science.gov (United States)

    Menon, P. K. A.; Cheng, V. H. L.; Kim, E.

    1990-01-01

    Two approaches for studying the pursuit-evasion problem between rotorcraft executing nap-of-the-earth flight are presented. The first of these employs a constant speed kinematic helicopter model, while the second approach uses a three degree of freedom point-mass model. The candidate solutions to the first differential game are generated by integrating the state-costate equations backward in time. The second problem employs feedback linearization to obtain guidance laws in nonlinear feedback form. Both approaches explicitly use the terrain profile data. Sample extremals are presented.

  11. Stochastic Game Approach to Guidance Design

    Science.gov (United States)

    1988-09-09

    maneuverable aircraft, which can employ also electronic counter measures, is formulated as an imper- fect information zero-sum pursuit-evasion game played...on Differential Game Applications [36]. However, some other examples which included " electronic jinking", indicated that in an ECM environment a mixed...radius, b) missile/target maneuver ratio, c) nonlinear maneuver similarity parameter (aE T2 max d) normalized end- game duration, e ) ini’tial end- game

  12. Pursit-evasion game analysis in a line of sight coordinate system

    Science.gov (United States)

    Shinar, J.; Davidovitz, A.

    1985-01-01

    The paper proposes to use line of sight coordinates for the analysis of pursuit-evasion games. The advantage of this method for two-target games is shown to be evident. As a demonstrative example the game of two identical cars is formulated and solved in such coordinate systems. A new type of singular surface, overlooked in a previous study of the same problem, is discovered as a consequence of the simplicity of the solution.

  13. Toward Simulating Realistic Pursuit-Evasion Using a Roadmap-Based Approach

    KAUST Repository

    Rodriguez, Samuel

    2010-01-01

    In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. We demonstrate the utility of this approach for a variety of scenarios including pursuit-evasion on terrains, in multi-level buildings, and in crowds. © 2010 Springer-Verlag Berlin Heidelberg.

  14. Differential games a mathematical theory with applications to warfare and pursuit, control and optimization

    CERN Document Server

    Isaacs, Rufus

    1999-01-01

    Definitive work draws on game theory, calculus of variations, and control theory to solve an array of problems: military, pursuit and evasion, athletic contests, many more. Detailed examples, formal calculations. 1965 edition.

  15. Toward realistic pursuit-evasion using a roadmap-based approach

    KAUST Repository

    Rodriguez, Samuel

    2011-05-01

    In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. Our approach can be applied to more realistic scenarios than are typically studied in most previous work, including agents moving in 3D environments such as terrains, multi-story buildings, and dynamic environments. We also support more realistic three-dimensional visibility computations that allow evading agents to hide in crowds or behind hills. We demonstrate the utility of this approach on mobile robots and in simulation for a variety of scenarios including pursuit-evasion and tag on terrains, in multi-level buildings, and in crowds. © 2011 IEEE.

  16. Pursuit/evasion in orbit

    Science.gov (United States)

    Kelley, H. J.; Cliff, E. M.; Lutze, F. H.

    1981-01-01

    Maneuvers available to a spacecraft having sufficient propellant to escape an antisatellite satellite (ASAT) attack are examined. The ASAT and the evading spacecraft are regarded as being in circular orbits, and equations of motion are developed for the ASAT to commence a two-impulse maneuver sequence. The ASAT employs thrust impulses which yield a minimum-time-to-rendezvous, considering available fuel. Optimal evasion is shown to involve only in-plane maneuvers, and begins as soon as the ASAT launch information is gathered and thrust activation can be initiated. A closest approach, along with a maximum evasion by the target spacecraft, is calculated to be 14,400 ft. Further research to account for ASATs in parking orbit and for generalization of a continuous control-modeled differential game is indicated.

  17. Toward Simulating Realistic Pursuit-Evasion Using a Roadmap-Based Approach

    KAUST Repository

    Rodriguez, Samuel; Denny, Jory; Zourntos, Takis; Amato, Nancy M.

    2010-01-01

    In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. We demonstrate

  18. Chases and escapes the mathematics of pursuit and evasion

    CERN Document Server

    Nahin, Paul J

    2012-01-01

    We all played tag when we were kids. What most of us don't realize is that this simple chase game is in fact an application of pursuit theory, and that the same principles of games like tag, dodgeball, and hide-and-seek are also at play in military strategy, high-seas chases by the Coast Guard, and even romantic pursuits. In Chases and Escapes, Paul Nahin gives us the first complete history of this fascinating area of mathematics, from its classical analytical beginnings to the present day. Drawing on game theory, geometry, linear algebra, target-tracking algorithms, and much

  19. Three-dimensional nonlinear H-infinity guidance design and H-infinity-based pursuit-evasion game

    Science.gov (United States)

    Chen, Hsin-Yuan; Yang, Chi-Ching

    2001-08-01

    There are five features in this approach: (1) The complete nonlinear dynamics of the pursuit-evasion motion is considered in 3D spherical coordinate system. Neither linearization nor small signal assumptions are made. (2) The nonlinear H-infinity guidance design is derived analytically and expressed in a very simple form. (3) Unlike adaptive control concept, implementation of the proposed H(infinity ) guidance design does not need the information on target acceleration while ensuring acceptable intercept performance for arbitrary targets with the finite acceleration. (4) The derived guidance design exhibits strong robustness against variations in target acceleration. (5) Finally the issues related to the validation of the control law using Hardware In The Loop simulation are presented. The effects of the Flight Motion Simulator static and dynamic accuracies (time delay etc...) are discussed.

  20. Tax evasion: a game countermeasure

    Directory of Open Access Journals (Sweden)

    David Carfi'

    2015-08-01

    Full Text Available We propose a game-theoretic model analyzing the interaction between the State and any possible relative taxpayer, by using a realistic probability (frequency approach to the checking evasion strategy. Starting from Allingham and Sandmo's model (1972, we study a possible measure to prevent tax evasion and we also propose a ``honesty-award'' for Taxpayers declaring their entire income by using two Kalai-Smorodinsky solutions. This methodology leaves room for further development of the model, leading to a self-identification by tax evaders and honest citizens.

  1. A Stochastic Growth Model with Income Tax Evasion: Implications for Australia

    OpenAIRE

    Ratbek Dzhumashev; Emin Gahramanov

    2009-01-01

    In this paper we develop a stochastic endogenous growth model augmented with income tax evasion. Our model avoids some existing discrepancies between empirical evidence and theoretical predictions of traditional tax evasion models. Further, we show that: i) productive government expenditures play an important role in affecting economy's tax evasion rate; ii) the average marginal income tax rate in Australia come close to the optimal; and iii) the phenomenon of tax evasion is not an excuse for...

  2. Differential games

    CERN Document Server

    Friedman, Avner

    2006-01-01

    This volume lays the mathematical foundations for the theory of differential games, developing a rigorous mathematical framework with existence theorems. It begins with a precise definition of a differential game and advances to considerations of games of fixed duration, games of pursuit and evasion, the computation of saddle points, games of survival, and games with restricted phase coordinates. Final chapters cover selected topics (including capturability and games with delayed information) and N-person games.Geared toward graduate students, Differential Games will be of particular interest

  3. Advances in dynamic and mean field games theory, applications, and numerical methods

    CERN Document Server

    Viscolani, Bruno

    2017-01-01

    This contributed volume considers recent advances in dynamic games and their applications, based on presentations given at the 17th Symposium of the International Society of Dynamic Games, held July 12-15, 2016, in Urbino, Italy. Written by experts in their respective disciplines, these papers cover various aspects of dynamic game theory including mean-field games, stochastic and pursuit-evasion games, and computational methods for dynamic games. Topics covered include Pedestrian flow in crowded environments Models for climate change negotiations Nash Equilibria for dynamic games involving Volterra integral equations Differential games in healthcare markets Linear-quadratic Gaussian dynamic games Aircraft control in wind shear conditions Advances in Dynamic and Mean-Field Games presents state-of-the-art research in a wide spectrum of areas. As such, it serves as a testament to the continued vitality and growth of the field of dynamic games and their applications. It will be of interest to an interdisciplinar...

  4. When hawks attack: animal-borne video studies of goshawk pursuit and prey-evasion strategies

    Science.gov (United States)

    Kane, Suzanne Amador; Fulton, Andrew H.; Rosenthal, Lee J.

    2015-01-01

    Video filmed by a camera mounted on the head of a Northern Goshawk (Accipiter gentilis) was used to study how the raptor used visual guidance to pursue prey and land on perches. A combination of novel image analysis methods and numerical simulations of mathematical pursuit models was used to determine the goshawk's pursuit strategy. The goshawk flew to intercept targets by fixing the prey at a constant visual angle, using classical pursuit for stationary prey, lures or perches, and usually using constant absolute target direction (CATD) for moving prey. Visual fixation was better maintained along the horizontal than vertical direction. In some cases, we observed oscillations in the visual fix on the prey, suggesting that the goshawk used finite-feedback steering. Video filmed from the ground gave similar results. In most cases, it showed goshawks intercepting prey using a trajectory consistent with CATD, then turning rapidly to attack by classical pursuit; in a few cases, it showed them using curving non-CATD trajectories. Analysis of the prey's evasive tactics indicated that only sharp sideways turns caused the goshawk to lose visual fixation on the prey, supporting a sensory basis for the surprising frequency and effectiveness of this tactic found by previous studies. The dynamics of the prey's looming image also suggested that the goshawk used a tau-based interception strategy. We interpret these results in the context of a concise review of pursuit–evasion in biology, and conjecture that some prey deimatic ‘startle’ displays may exploit tau-based interception. PMID:25609783

  5. A Tax Evasion - Bribery Game: Experimental Evidence from Ukraine

    Directory of Open Access Journals (Sweden)

    Volodymyr Bilotkach

    2006-06-01

    Full Text Available This paper examines the issue of tax evasion by enterprises through underreporting activity. We develop a view of this phenomenon as an equilibrium of the game between a businessman and an imperfectly monitored supervising official, in which a businessman can hide part of his profit and offer bribe to official. We determine conditions under which such tax evasion and bribery become wide-spread in the society, resulting in shadow economy. The game is put into an experimental setting in Kiev, Ukraine, with the emphasis of spreading of the tax evasion and bribery activity in the laboratory setting. We find that once it becomes known that substantial share of subjects playing the role of supervising officials agree to accept bribes from subjects playing the role of businessmen, the latter offer bribes more aggressively. Yet, this in turn does not affect the behavior of subjects playing the role of supervising officials.

  6. Exact Algorithms for Solving Stochastic Games

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Koucky, Michal; Lauritzen, Niels

    2012-01-01

    Shapley's discounted stochastic games, Everett's recursive games and Gillette's undiscounted stochastic games are classical models of game theory describing two-player zero-sum games of potentially infinite duration. We describe algorithms for exactly solving these games....

  7. Capturability in a two-target "Game of two cars"

    CSIR Research Space (South Africa)

    Getz, WM

    1981-01-01

    Full Text Available The regions of capturability and draw are derived for a two-target pursuit-evasion differential game of two cars. Specifically, using geometric arguments, complete barrier surfaces are constructed that emanate from the boundaries of the usable parts...

  8. On the analysis of a complex differential game using artificial intelligence techniques [military systems

    NARCIS (Netherlands)

    Shinar, J.; Siegel, A.W.

    1988-01-01

    The investigation is motivated by the dynamic conflict in an air-to-air combat between two aggressive aircraft, both equipped with medium-range guided missiles. It is a two-target differential game with two independent pursuit-evasion games. A description is given of the analysis of the conflict by

  9. On Nash Equilibria in Stochastic Games

    Science.gov (United States)

    2003-10-01

    Traditionally automata theory and veri cation has considered zero sum or strictly competitive versions of stochastic games . In these games there are two players...zero- sum discrete-time stochastic dynamic games . SIAM J. Control and Optimization, 19(5):617{634, 1981. 18. R.J. Lipton, E . Markakis, and A. Mehta...Playing large games using simple strate- gies. In EC 03: Electronic Commerce, pages 36{41. ACM Press, 2003. 19. A. Maitra and W. Sudderth. Finitely

  10. Linear Pursuit Differential Game under Phase Constraint on the State of Evader

    Directory of Open Access Journals (Sweden)

    Askar Rakhmanov

    2016-01-01

    Full Text Available We consider a linear pursuit differential game of one pursuer and one evader. Controls of the pursuer and evader are subjected to integral and geometric constraints, respectively. In addition, phase constraint is imposed on the state of evader, whereas pursuer moves throughout the space. We say that pursuit is completed, if inclusion y(t1-x(t1∈M is satisfied at some t1>0, where x(t and y(t are states of pursuer and evader, respectively, and M is terminal set. Conditions of completion of pursuit in the game from all initial points of players are obtained. Strategy of the pursuer is constructed so that the phase vector of the pursuer first is brought to a given set, and then pursuit is completed.

  11. A Nucleolus for Stochastic Cooperative Games

    OpenAIRE

    Suijs, J.P.M.

    1996-01-01

    This paper extends the definition of the nucleolus to stochastic cooperative games, that is, to cooperative games with random payoffs to the coalitions. It is shown that the nucleolus is nonempty and that it belongs to the core whenever the core is nonempty. Furthermore, it is shown for a particular class of stochastic cooperative games that the nucleolus can be determined by calculating the traditional nucleolus introduced by Schmeidler (1969) of a specific deterministic cooperative game.

  12. Succession of hide-seek and pursuit-evasion at heterogeneous locations.

    Science.gov (United States)

    Gal, Shmuel; Casas, Jérôme

    2014-05-06

    Many interactions between searching agents and their elusive targets are composed of a succession of steps, whether in the context of immune systems, predation or counterterrorism. In the simplest case, a two-step process starts with a search-and-hide phase, also called a hide-and-seek phase, followed by a round of pursuit-escape. Our aim is to link these two processes, usually analysed separately and with different models, in a single game theory context. We define a matrix game in which a searcher looks at a fixed number of discrete locations only once each searching for a hider, which can escape with varying probabilities according to its location. The value of the game is the overall probability of capture after k looks. The optimal search and hide strategies are described. If a searcher looks only once into any of the locations, an optimal hider chooses it's hiding place so as to make all locations equally attractive. This optimal strategy remains true as long as the number of looks is below an easily calculated threshold; however, above this threshold, the optimal position for the hider is where it has the highest probability of escaping once spotted.

  13. The Owen Value of Stochastic Cooperative Game

    Directory of Open Access Journals (Sweden)

    Cheng-Guo E

    2014-01-01

    Full Text Available We consider stochastic cooperative game and give it the definition of the Owen value, which is obtained by extending the classical case. Then we provide explicit expression for the Owen value of the stochastic cooperative game and discuss its existence and uniqueness.

  14. Integrated detection, estimation, and guidance in pursuit of a maneuvering target

    Science.gov (United States)

    Dionne, Dany

    The thesis focuses on efficient solutions of non-cooperative pursuit-evasion games with imperfect information on the state of the system. This problem is important in the context of interception of future maneuverable ballistic missiles. However, the theoretical developments are expected to find application to a broad class of hybrid control and estimation problems in industry. The validity of the results is nevertheless confirmed using a benchmark problem in the area of terminal guidance. A specific interception scenario between an incoming target with no information and a single interceptor missile with noisy measurements is analyzed in the form of a linear hybrid system subject to additive abrupt changes. The general research is aimed to achieve improved homing accuracy by integrating ideas from detection theory, state estimation theory and guidance. The results achieved can be summarized as follows. (i) Two novel maneuver detectors are developed to diagnose abrupt changes in a class of hybrid systems (detection and isolation of evasive maneuvers): a new implementation of the GLR detector and the novel adaptive- H0 GLR detector. (ii) Two novel state estimators for target tracking are derived using the novel maneuver detectors. The state estimators employ parameterized family of functions to described possible evasive maneuvers. (iii) A novel adaptive Bayesian multiple model predictor of the ballistic miss is developed which employs semi-Markov models and ideas from detection theory. (iv) A novel integrated estimation and guidance scheme that significantly improves the homing accuracy is also presented. The integrated scheme employs banks of estimators and guidance laws, a maneuver detector, and an on-line governor; the scheme is adaptive with respect to the uncertainty affecting the probability density function of the filtered state. (v) A novel discretization technique for the family of continuous-time, game theoretic, bang-bang guidance laws is introduced. The

  15. LP formulation of asymmetric zero-sum stochastic games

    KAUST Repository

    Li, Lichun

    2014-12-15

    This paper provides an efficient linear programming (LP) formulation of asymmetric two player zero-sum stochastic games with finite horizon. In these stochastic games, only one player is informed of the state at each stage, and the transition law is only controlled by the informed player. Compared with the LP formulation of extensive stochastic games whose size grows polynomially with respect to the size of the state and the size of the uninformed player\\'s actions, our proposed LP formulation has its size to be linear with respect to the size of the state and the size of the uninformed player, and hence greatly reduces the computational complexity. A travelling inspector problem is used to demonstrate the efficiency of the proposed LP formulation.

  16. LP formulation of asymmetric zero-sum stochastic games

    KAUST Repository

    Li, Lichun; Shamma, Jeff S.

    2014-01-01

    This paper provides an efficient linear programming (LP) formulation of asymmetric two player zero-sum stochastic games with finite horizon. In these stochastic games, only one player is informed of the state at each stage, and the transition law is only controlled by the informed player. Compared with the LP formulation of extensive stochastic games whose size grows polynomially with respect to the size of the state and the size of the uninformed player's actions, our proposed LP formulation has its size to be linear with respect to the size of the state and the size of the uninformed player, and hence greatly reduces the computational complexity. A travelling inspector problem is used to demonstrate the efficiency of the proposed LP formulation.

  17. Balancing Two-Player Stochastic Games with Soft Q-Learning

    OpenAIRE

    Grau-Moya, Jordi; Leibfried, Felix; Bou-Ammar, Haitham

    2018-01-01

    Within the context of video games the notion of perfectly rational agents can be undesirable as it leads to uninteresting situations, where humans face tough adversarial decision makers. Current frameworks for stochastic games and reinforcement learning prohibit tuneable strategies as they seek optimal performance. In this paper, we enable such tuneable behaviour by generalising soft Q-learning to stochastic games, where more than one agent interact strategically. We contribute both theoretic...

  18. A Nucleolus for Stochastic Cooperative Games

    NARCIS (Netherlands)

    Suijs, J.P.M.

    1996-01-01

    This paper extends the definition of the nucleolus to stochastic cooperative games, that is, to cooperative games with random payoffs to the coalitions. It is shown that the nucleolus is nonempty and that it belongs to the core whenever the core is nonempty. Furthermore, it is shown for a particular

  19. Pathwise Strategies for Stochastic Differential Games with an Erratum to “Stochastic Differential Games with Asymmetric Information”

    International Nuclear Information System (INIS)

    Cardaliaguet, P.; Rainer, C.

    2013-01-01

    We introduce a new notion of pathwise strategies for stochastic differential games. This allows us to give a correct meaning to some statement asserted in Cardaliaguet and Rainer (Appl. Math. Optim. 59: 1–36, 2009)

  20. Stochastic heterogeneous interaction promotes cooperation in spatial prisoner's dilemma game.

    Directory of Open Access Journals (Sweden)

    Ping Zhu

    Full Text Available Previous studies mostly investigate player's cooperative behavior as affected by game time-scale or individual diversity. In this paper, by involving both time-scale and diversity simultaneously, we explore the effect of stochastic heterogeneous interaction. In our model, the occurrence of game interaction between each pair of linked player obeys a random probability, which is further described by certain distributions. Simulations on a 4-neighbor square lattice show that the cooperation level is remarkably promoted when stochastic heterogeneous interaction is considered. The results are then explained by investigating the mean payoffs, the mean boundary payoffs and the transition probabilities between cooperators and defectors. We also show some typical snapshots and evolution time series of the system. Finally, the 8-neighbor square lattice and BA scale-free network results indicate that the stochastic heterogeneous interaction can be robust against different network topologies. Our work may sharpen the understanding of the joint effect of game time-scale and individual diversity on spatial games.

  1. Stochastic Learning and the Intuitive Criterion in Simple Signaling Games

    DEFF Research Database (Denmark)

    Sloth, Birgitte; Whitta-Jacobsen, Hans Jørgen

    A stochastic learning process for signaling games with two types, two signals, and two responses gives rise to equilibrium selection which is in remarkable accordance with the selection obtained by the intuitive criterion......A stochastic learning process for signaling games with two types, two signals, and two responses gives rise to equilibrium selection which is in remarkable accordance with the selection obtained by the intuitive criterion...

  2. Path to Stochastic Stability: Comparative Analysis of Stochastic Learning Dynamics in Games

    KAUST Repository

    Jaleel, Hassan

    2018-04-08

    Stochastic stability is a popular solution concept for stochastic learning dynamics in games. However, a critical limitation of this solution concept is its inability to distinguish between different learning rules that lead to the same steady-state behavior. We address this limitation for the first time and develop a framework for the comparative analysis of stochastic learning dynamics with different update rules but same steady-state behavior. We present the framework in the context of two learning dynamics: Log-Linear Learning (LLL) and Metropolis Learning (ML). Although both of these dynamics have the same stochastically stable states, LLL and ML correspond to different behavioral models for decision making. Moreover, we demonstrate through an example setup of sensor coverage game that for each of these dynamics, the paths to stochastically stable states exhibit distinctive behaviors. Therefore, we propose multiple criteria to analyze and quantify the differences in the short and medium run behavior of stochastic learning dynamics. We derive and compare upper bounds on the expected hitting time to the set of Nash equilibria for both LLL and ML. For the medium to long-run behavior, we identify a set of tools from the theory of perturbed Markov chains that result in a hierarchical decomposition of the state space into collections of states called cycles. We compare LLL and ML based on the proposed criteria and develop invaluable insights into the comparative behavior of the two dynamics.

  3. Pathwise Strategies for Stochastic Differential Games with an Erratum to 'Stochastic Differential Games with Asymmetric Information'

    Energy Technology Data Exchange (ETDEWEB)

    Cardaliaguet, P., E-mail: cardaliaguet@ceremade.dauphine.fr [Universite Paris-Dauphine, Ceremade (France); Rainer, C., E-mail: Catherine.Rainer@univ-brest.fr [Universite de Bretagne Occidentale (France)

    2013-08-01

    We introduce a new notion of pathwise strategies for stochastic differential games. This allows us to give a correct meaning to some statement asserted in Cardaliaguet and Rainer (Appl. Math. Optim. 59: 1-36, 2009)

  4. Evasion in the plane

    Science.gov (United States)

    Leitmann, G.; Liu, H. S.

    1977-01-01

    Dynamic systems were considered subject to control by two agents, one of whom desires that no trajectory of the system emanating from outside a given set, intersects that set no matter what the admissible actions of the other agent. Constructive conditions sufficient to yield a feedback control for the agent seeking avoidance were employed to deduce an evader control for the planar pursuit-evasion problem with bounded normal accelerations.

  5. Stochastic Strategy Adjustment in Coordination Games

    NARCIS (Netherlands)

    Kosfeld, M.

    1999-01-01

    We explore a model of equilibrium selection in coordination games, where agents stochastically adjust their strategies to changes in their local environment. Instead of playing perturbed best-response, we assume that agents follow a rule of "switching to better strategies more likely". We relate

  6. An Analysis of Stochastic Game Theory for Multiagent Reinforcement Learning

    National Research Council Canada - National Science Library

    Bowling, Michael

    2000-01-01

    .... In this paper we contribute a comprehensive presentation of the relevant techniques for solving stochastic games from both the game theory community and reinforcement learning communities. We examine the assumptions and limitations of these algorithms, and identify similarities between these algorithms, single agent reinforcement learners, and basic game theory techniques.

  7. Mean Field Games for Stochastic Growth with Relative Utility

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Minyi, E-mail: mhuang@math.carleton.ca [Carleton University, School of Mathematics and Statistics (Canada); Nguyen, Son Luu, E-mail: sonluu.nguyen@upr.edu [University of Puerto Rico, Department of Mathematics (United States)

    2016-12-15

    This paper considers continuous time stochastic growth-consumption optimization in a mean field game setting. The individual capital stock evolution is determined by a Cobb–Douglas production function, consumption and stochastic depreciation. The individual utility functional combines an own utility and a relative utility with respect to the population. The use of the relative utility reflects human psychology, leading to a natural pattern of mean field interaction. The fixed point equation of the mean field game is derived with the aid of some ordinary differential equations. Due to the relative utility interaction, our performance analysis depends on some ratio based approximation error estimate.

  8. Mean Field Games for Stochastic Growth with Relative Utility

    International Nuclear Information System (INIS)

    Huang, Minyi; Nguyen, Son Luu

    2016-01-01

    This paper considers continuous time stochastic growth-consumption optimization in a mean field game setting. The individual capital stock evolution is determined by a Cobb–Douglas production function, consumption and stochastic depreciation. The individual utility functional combines an own utility and a relative utility with respect to the population. The use of the relative utility reflects human psychology, leading to a natural pattern of mean field interaction. The fixed point equation of the mean field game is derived with the aid of some ordinary differential equations. Due to the relative utility interaction, our performance analysis depends on some ratio based approximation error estimate.

  9. Efficient computation of discounted asymmetric information zero-sum stochastic games

    KAUST Repository

    Li, Lichun; Shamma, Jeff S.

    2015-01-01

    In asymmetric information zero-sum games, one player has superior information about the game over the other. Asymmetric information games are particularly relevant for security problems, e.g., where an attacker knows its own skill set or alternatively a system administrator knows the state of its resources. In such settings, the informed player is faced with the tradeoff of exploiting its superior information at the cost of revealing its superior information. This tradeoff is typically addressed through randomization, in an effort to keep the uninformed player informationally off balance. A lingering issue is the explicit computation of such strategies. This paper, building on prior work for repeated games, presents an LP formulation to compute suboptimal strategies for the informed player in discounted asymmetric information stochastic games in which state transitions are not affected by the uninformed player. Furthermore, the paper presents bounds between the security level guaranteed by the sub-optimal strategy and the optimal value. The results are illustrated on a stochastic intrusion detection problem.

  10. Efficient computation of discounted asymmetric information zero-sum stochastic games

    KAUST Repository

    Li, Lichun

    2015-12-15

    In asymmetric information zero-sum games, one player has superior information about the game over the other. Asymmetric information games are particularly relevant for security problems, e.g., where an attacker knows its own skill set or alternatively a system administrator knows the state of its resources. In such settings, the informed player is faced with the tradeoff of exploiting its superior information at the cost of revealing its superior information. This tradeoff is typically addressed through randomization, in an effort to keep the uninformed player informationally off balance. A lingering issue is the explicit computation of such strategies. This paper, building on prior work for repeated games, presents an LP formulation to compute suboptimal strategies for the informed player in discounted asymmetric information stochastic games in which state transitions are not affected by the uninformed player. Furthermore, the paper presents bounds between the security level guaranteed by the sub-optimal strategy and the optimal value. The results are illustrated on a stochastic intrusion detection problem.

  11. Stochastic Frontier Estimation of Efficient Learning in Video Games

    Science.gov (United States)

    Hamlen, Karla R.

    2012-01-01

    Stochastic Frontier Regression Analysis was used to investigate strategies and skills that are associated with the minimization of time required to achieve proficiency in video games among students in grades four and five. Students self-reported their video game play habits, including strategies and skills used to become good at the video games…

  12. Solving simple stochastic games with few coin toss positions

    DEFF Research Database (Denmark)

    Ibsen-Jensen, Rasmus; Miltersen, Peter Bro

    2011-01-01

    Gimbert and Horn gave an algorithm for solving simple stochastic games with running time O(r! n) where n is the number of positions of the simple stochastic game and r is the number of its coin toss positions. Chatterjee et al. pointed out that a variant of strategy iteration can be implemented...... to solve this problem in time 4^r r^{O(1)} n^{O(1)}. In this paper, we show that an algorithm combining value iteration with retrograde analysis achieves a time bound of O(r 2^r (r log r + n)), thus improving both time bounds. While the algorithm is simple, the analysis leading to this time bound...

  13. Conic surveillance evasion

    NARCIS (Netherlands)

    Lewin, J.; Olsder, G.J.

    1979-01-01

    A surveillance-evasion differential game of degree with a detection zone in the shape of a two-dimensional cone is posed. The nature of the optimal strategies and the singular phenomena of the value function are described and correlated to subsets of the space of all possible parameter combinations,

  14. Monomial strategies for concurrent reachability games and other stochastic games

    DEFF Research Database (Denmark)

    Frederiksen, Søren Kristoffer Stiil; Miltersen, Peter Bro

    2013-01-01

    We consider two-player zero-sum finite (but infinite-horizon) stochastic games with limiting average payoffs. We define a family of stationary strategies for Player I parameterized by ε > 0 to be monomial, if for each state k and each action j of Player I in state k except possibly one action, we...... have that the probability of playing j in k is given by an expression of the form c ε d for some non-negative real number c and some non-negative integer d. We show that for all games, there is a monomial family of stationary strategies that are ε-optimal among stationary strategies. A corollary...... is that all concurrent reachability games have a monomial family of ε-optimal strategies. This generalizes a classical result of de Alfaro, Henzinger and Kupferman who showed that this is the case for concurrent reachability games where all states have value 0 or 1....

  15. Stochastic Perron's method and elementary strategies for zero-sum differential games

    OpenAIRE

    Sîrbu, Mihai

    2013-01-01

    We develop here the Stochastic Perron Method in the framework of two-player zero-sum differential games. We consider the formulation of the game where both players play, symmetrically, feed-back strategies (as in [CR09] or [PZ12]) as opposed to the Elliott-Kalton formulation prevalent in the literature. The class of feed-back strategies we use is carefully chosen so that the state equation admits strong solutions and the technicalities involved in the Stochastic Perron Method carry through in...

  16. Stochastic Cooperative Games in Insurance and Reinsurance

    NARCIS (Netherlands)

    Suijs, J.P.M.; De Waegenaere, A.M.B.; Borm, P.E.M.

    1996-01-01

    This paper shows how problems in `non life'-insurance and `non life'-reinsurance can be modelled simultaneously as cooperative games with stochastic payoffs.Pareto optimal allocations of the risks faced by the insurers and the insureds are determined.It is shown that the core of the corresponding

  17. Stochastic noncooperative and cooperative evolutionary game strategies of a population of biological networks under natural selection.

    Science.gov (United States)

    Chen, Bor-Sen; Yeh, Chin-Hsun

    2017-12-01

    We review current static and dynamic evolutionary game strategies of biological networks and discuss the lack of random genetic variations and stochastic environmental disturbances in these models. To include these factors, a population of evolving biological networks is modeled as a nonlinear stochastic biological system with Poisson-driven genetic variations and random environmental fluctuations (stimuli). To gain insight into the evolutionary game theory of stochastic biological networks under natural selection, the phenotypic robustness and network evolvability of noncooperative and cooperative evolutionary game strategies are discussed from a stochastic Nash game perspective. The noncooperative strategy can be transformed into an equivalent multi-objective optimization problem and is shown to display significantly improved network robustness to tolerate genetic variations and buffer environmental disturbances, maintaining phenotypic traits for longer than the cooperative strategy. However, the noncooperative case requires greater effort and more compromises between partly conflicting players. Global linearization is used to simplify the problem of solving nonlinear stochastic evolutionary games. Finally, a simple stochastic evolutionary model of a metabolic pathway is simulated to illustrate the procedure of solving for two evolutionary game strategies and to confirm and compare their respective characteristics in the evolutionary process. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Solving Simple Stochastic Games with Few Coin Toss Positions

    DEFF Research Database (Denmark)

    Ibsen-Jensen, Rasmus; Miltersen, Peter Bro

    2012-01-01

    Gimbert and Horn gave an algorithm for solving simple stochastic games with running time O(r! n) where n is the number of positions of the simple stochastic game and r is the number of its coin toss positions. Chatterjee et al. pointed out that a variant of strategy iteration can be implemented...... to solve this problem in time 4 r n O(1). In this paper, we show that an algorithm combining value iteration with retrograde analysis achieves a time bound of O(r 2 r (r logr + n)), thus improving both time bounds. We also improve the analysis of Chatterjee et al. and show that their algorithm in fact has...

  19. Spatial effect on stochastic dynamics of bistable evolutionary games

    International Nuclear Information System (INIS)

    So, Kohaku H Z; Ohtsuki, Hisashi; Kato, Takeo

    2014-01-01

    We consider the lifetimes of metastable states in bistable evolutionary games (coordination games), and examine how they are affected by spatial structure. A semiclassical approximation based on a path integral method is applied to stochastic evolutionary game dynamics with and without spatial structure, and the lifetimes of the metastable states are evaluated. It is shown that the population dependence of the lifetimes is qualitatively different in these two models. Our result indicates that spatial structure can accelerate the transitions between metastable states. (paper)

  20. Construction of Barrier in a Fishing Game With Point Capture.

    Science.gov (United States)

    Zha, Wenzhong; Chen, Jie; Peng, Zhihong; Gu, Dongbing

    2017-06-01

    This paper addresses a particular pursuit-evasion game, called as "fishing game" where a faster evader attempts to pass the gap between two pursuers. We are concerned with the conditions under which the evader or pursuers can win the game. This is a game of kind in which an essential aspect, barrier, separates the state space into disjoint parts associated with each player's winning region. We present a method of explicit policy to construct the barrier. This method divides the fishing game into two subgames related to the included angle and the relative distances between the evader and the pursuers, respectively, and then analyzes the possibility of capture or escape for each subgame to ascertain the analytical forms of the barrier. Furthermore, we fuse the games of kind and degree by solving the optimal control strategies in the minimum time for each player when the initial state lies in their winning regions. Along with the optimal strategies, the trajectories of the players are delineated and the upper bounds of their winning times are also derived.

  1. Non-cooperative stochastic differential game theory of generalized Markov jump linear systems

    CERN Document Server

    Zhang, Cheng-ke; Zhou, Hai-ying; Bin, Ning

    2017-01-01

    This book systematically studies the stochastic non-cooperative differential game theory of generalized linear Markov jump systems and its application in the field of finance and insurance. The book is an in-depth research book of the continuous time and discrete time linear quadratic stochastic differential game, in order to establish a relatively complete framework of dynamic non-cooperative differential game theory. It uses the method of dynamic programming principle and Riccati equation, and derives it into all kinds of existence conditions and calculating method of the equilibrium strategies of dynamic non-cooperative differential game. Based on the game theory method, this book studies the corresponding robust control problem, especially the existence condition and design method of the optimal robust control strategy. The book discusses the theoretical results and its applications in the risk control, option pricing, and the optimal investment problem in the field of finance and insurance, enriching the...

  2. A game-theoretic method for cross-layer stochastic resilient control design in CPS

    Science.gov (United States)

    Shen, Jiajun; Feng, Dongqin

    2018-03-01

    In this paper, the cross-layer security problem of cyber-physical system (CPS) is investigated from the game-theoretic perspective. Physical dynamics of plant is captured by stochastic differential game with cyber-physical influence being considered. The sufficient and necessary condition for the existence of state-feedback equilibrium strategies is given. The attack-defence cyber interactions are formulated by a Stackelberg game intertwined with stochastic differential game in physical layer. The condition such that the Stackelberg equilibrium being unique and the corresponding analytical solutions are both provided. An algorithm is proposed for obtaining hierarchical security strategy by solving coupled games, which ensures the operational normalcy and cyber security of CPS subject to uncertain disturbance and unexpected cyberattacks. Simulation results are given to show the effectiveness and performance of the proposed algorithm.

  3. The Dynamic Programming Method of Stochastic Differential Game for Functional Forward-Backward Stochastic System

    Directory of Open Access Journals (Sweden)

    Shaolin Ji

    2013-01-01

    Full Text Available This paper is devoted to a stochastic differential game (SDG of decoupled functional forward-backward stochastic differential equation (FBSDE. For our SDG, the associated upper and lower value functions of the SDG are defined through the solution of controlled functional backward stochastic differential equations (BSDEs. Applying the Girsanov transformation method introduced by Buckdahn and Li (2008, the upper and the lower value functions are shown to be deterministic. We also generalize the Hamilton-Jacobi-Bellman-Isaacs (HJBI equations to the path-dependent ones. By establishing the dynamic programming principal (DPP, we derive that the upper and the lower value functions are the viscosity solutions of the corresponding upper and the lower path-dependent HJBI equations, respectively.

  4. Robust synthetic biology design: stochastic game theory approach.

    Science.gov (United States)

    Chen, Bor-Sen; Chang, Chia-Hung; Lee, Hsiao-Ching

    2009-07-15

    Synthetic biology is to engineer artificial biological systems to investigate natural biological phenomena and for a variety of applications. However, the development of synthetic gene networks is still difficult and most newly created gene networks are non-functioning due to uncertain initial conditions and disturbances of extra-cellular environments on the host cell. At present, how to design a robust synthetic gene network to work properly under these uncertain factors is the most important topic of synthetic biology. A robust regulation design is proposed for a stochastic synthetic gene network to achieve the prescribed steady states under these uncertain factors from the minimax regulation perspective. This minimax regulation design problem can be transformed to an equivalent stochastic game problem. Since it is not easy to solve the robust regulation design problem of synthetic gene networks by non-linear stochastic game method directly, the Takagi-Sugeno (T-S) fuzzy model is proposed to approximate the non-linear synthetic gene network via the linear matrix inequality (LMI) technique through the Robust Control Toolbox in Matlab. Finally, an in silico example is given to illustrate the design procedure and to confirm the efficiency and efficacy of the proposed robust gene design method. http://www.ee.nthu.edu.tw/bschen/SyntheticBioDesign_supplement.pdf.

  5. A Pumping Algorithm for Ergodic Stochastic Mean Payoff Games with Perfect Information

    Science.gov (United States)

    Boros, Endre; Elbassioni, Khaled; Gurvich, Vladimir; Makino, Kazuhisa

    In this paper, we consider two-person zero-sum stochastic mean payoff games with perfect information, or BWR-games, given by a digraph G = (V = V B ∪ V W ∪ V R , E), with local rewards r: E to { R}, and three types of vertices: black V B , white V W , and random V R . The game is played by two players, White and Black: When the play is at a white (black) vertex v, White (Black) selects an outgoing arc (v,u). When the play is at a random vertex v, a vertex u is picked with the given probability p(v,u). In all cases, Black pays White the value r(v,u). The play continues forever, and White aims to maximize (Black aims to minimize) the limiting mean (that is, average) payoff. It was recently shown in [7] that BWR-games are polynomially equivalent with the classical Gillette games, which include many well-known subclasses, such as cyclic games, simple stochastic games (SSG's), stochastic parity games, and Markov decision processes. In this paper, we give a new algorithm for solving BWR-games in the ergodic case, that is when the optimal values do not depend on the initial position. Our algorithm solves a BWR-game by reducing it, using a potential transformation, to a canonical form in which the optimal strategies of both players and the value for every initial position are obvious, since a locally optimal move in it is optimal in the whole game. We show that this algorithm is pseudo-polynomial when the number of random nodes is constant. We also provide an almost matching lower bound on its running time, and show that this bound holds for a wider class of algorithms. Let us add that the general (non-ergodic) case is at least as hard as SSG's, for which no pseudo-polynomial algorithm is known.

  6. Fixation and escape times in stochastic game learning

    International Nuclear Information System (INIS)

    Realpe-Gomez, John; Szczesny, Bartosz; Galla, Tobias; Dall’Asta, Luca

    2012-01-01

    Evolutionary dynamics in finite populations is known to fixate eventually in the absence of mutation. We here show that a similar phenomenon can be found in stochastic game dynamical batch learning, and investigate fixation in learning processes in a simple 2×2 game, for two-player games with cyclic interaction, and in the context of the best-shot network game. The analogues of finite populations in evolution are here finite batches of observations between strategy updates. We study when and how such fixation can occur, and present results on the average time-to-fixation from numerical simulations. Simple cases are also amenable to analytical approaches and we provide estimates of the behaviour of so-called escape times as a function of the batch size. The differences and similarities with escape and fixation in evolutionary dynamics are discussed. (paper)

  7. Fast distributed strategic learning for global optima in queueing access games

    KAUST Repository

    Tembine, Hamidou

    2014-08-24

    In this paper we examine combined fully distributed payoff and strategy learning (CODIPAS) in a queue-aware access game over a graph. The classical strategic learning analysis relies on vanishing or small learning rate and uses stochastic approximation tool to derive steady states and invariant sets of the underlying learning process. Here, the stochastic approximation framework does not apply due to non-vanishing learning rate. We propose a direct proof of convergence of the process. Interestingly, the convergence time to one of the global optima is almost surely finite and we explicitly characterize the convergence time. We show that pursuit-based CODIPAS learning is much faster than the classical learning algorithms in games. We extend the methodology to coalitional learning and proves a very fast formation of coalitions for queue-aware access games where the action space is dynamically changing depending on the location of the user over a graph.

  8. Cooperative option of pursuit game with two pursuers and one evader. A strong stability of division variety

    Directory of Open Access Journals (Sweden)

    Viktor D. Shiryayev

    2017-06-01

    Full Text Available Introduction: The article deals with a simple differential game on the plane of pursuit with two consistently active players and one evader E; the game is considered in the form of the characteristic function. Materials and Methods: The geometric constructions and methods are used for solving the problem. The security zone of the escapee is bounded by the Apollonius circle, the pursuit team uses a strategy of parallel approach. Results: A method of finding the optimal players strategies and the optimal players’ trajectory is proposed. The way of forming the characteristic function is provided. All the variety of division is considered as a solution. However, the use of the results of cooperative theory of differential games is impossible without solving the problems associated with the specifics of differential equations of motion. Foremost, it is the problem of dynamic stability of optimality principles. The article introduces an auxiliary function of making the redistribution of winnings in time, keeping his total winnings throughout the game. The dynamic stability of the cooperative solution is determined with the help of this function. Strong dynamic stability of the entire set of solutions is shown. Discussion and Conclusions: The obtained results are consistent with similar research of other authors. Further research in this field can be used in the development of methods for “regularization” of optimality principles, for which the condition of dynamic stability is always fulfilled.

  9. Stochastic Local Search for Core Membership Checking in Hedonic Games

    Science.gov (United States)

    Keinänen, Helena

    Hedonic games have emerged as an important tool in economics and show promise as a useful formalism to model multi-agent coalition formation in AI as well as group formation in social networks. We consider a coNP-complete problem of core membership checking in hedonic coalition formation games. No previous algorithms to tackle the problem have been presented. In this work, we overcome this by developing two stochastic local search algorithms for core membership checking in hedonic games. We demonstrate the usefulness of the algorithms by showing experimentally that they find solutions efficiently, particularly for large agent societies.

  10. Stochastic evolutionary voluntary public goods game with punishment in a Quasi-birth-and-death process.

    Science.gov (United States)

    Quan, Ji; Liu, Wei; Chu, Yuqing; Wang, Xianjia

    2017-11-23

    Traditional replication dynamic model and the corresponding concept of evolutionary stable strategy (ESS) only takes into account whether the system can return to the equilibrium after being subjected to a small disturbance. In the real world, due to continuous noise, the ESS of the system may not be stochastically stable. In this paper, a model of voluntary public goods game with punishment is studied in a stochastic situation. Unlike the existing model, we describe the evolutionary process of strategies in the population as a generalized quasi-birth-and-death process. And we investigate the stochastic stable equilibrium (SSE) instead. By numerical experiments, we get all possible SSEs of the system for any combination of parameters, and investigate the influence of parameters on the probabilities of the system to select different equilibriums. It is found that in the stochastic situation, the introduction of the punishment and non-participation strategies can change the evolutionary dynamics of the system and equilibrium of the game. There is a large range of parameters that the system selects the cooperative states as its SSE with a high probability. This result provides us an insight and control method for the evolution of cooperation in the public goods game in stochastic situations.

  11. Tax evasion under behavioral structures

    Directory of Open Access Journals (Sweden)

    Gabriela S. Pantoja

    2014-01-01

    Full Text Available We study the strategic interactions between the fiscal authority and the taxpayer regarding tax evasion and auditing. We fit this interaction into a Bayesian game and introduce the concept of behavioral consistency, which helps reducing the number of available strategies and models the stylized fact according to which the choice to evade is subject to behavioral patterns.

  12. Set-Theoretic Inequalities in Stochastic Noncooperative Games with Coalition

    Directory of Open Access Journals (Sweden)

    Ailada Treerattrakoon

    2008-04-01

    Full Text Available We model and analyze antagonistic stochastic games of three players, two of whom form a coalition against the third one. The actions of the players are modeled by random walk processes recording the cumulative damages to each player at any moment of time. The game continues until the single player or the coalition is defeated. The defeat of any particular player takes place when the associated process (representing the collateral damage crosses a fixed threshold. Once the threshold is exceeded at some time, the associated player exits the game. All involved processes are being “observed by a third party process” so that the information regarding the status of all players is restricted to those special epochs. Furthermore, all processed are modulated (with their parameters being modified in due course of the game. We obtain a closed form joint functional of the named processes at key reference points.

  13. Modeling and Computation of Transboundary Industrial Pollution with Emission Permits Trading by Stochastic Differential Game.

    Science.gov (United States)

    Chang, Shuhua; Wang, Xinyu; Wang, Zheng

    2015-01-01

    Transboundary industrial pollution requires international actions to control its formation and effects. In this paper, we present a stochastic differential game to model the transboundary industrial pollution problems with emission permits trading. More generally, the process of emission permits price is assumed to be stochastic and to follow a geometric Brownian motion (GBM). We make use of stochastic optimal control theory to derive the system of Hamilton-Jacobi-Bellman (HJB) equations satisfied by the value functions for the cooperative and the noncooperative games, respectively, and then propose a so-called fitted finite volume method to solve it. The efficiency and the usefulness of this method are illustrated by the numerical experiments. The two regions' cooperative and noncooperative optimal emission paths, which maximize the regions' discounted streams of the net revenues, together with the value functions, are obtained. Additionally, we can also obtain the threshold conditions for the two regions to decide whether they cooperate or not in different cases. The effects of parameters in the established model on the results have been also examined. All the results demonstrate that the stochastic emission permits prices can motivate the players to make more flexible strategic decisions in the games.

  14. Stochastic Evolution Dynamic of the Rock-Scissors-Paper Game Based on a Quasi Birth and Death Process.

    Science.gov (United States)

    Yu, Qian; Fang, Debin; Zhang, Xiaoling; Jin, Chen; Ren, Qiyu

    2016-06-27

    Stochasticity plays an important role in the evolutionary dynamic of cyclic dominance within a finite population. To investigate the stochastic evolution process of the behaviour of bounded rational individuals, we model the Rock-Scissors-Paper (RSP) game as a finite, state dependent Quasi Birth and Death (QBD) process. We assume that bounded rational players can adjust their strategies by imitating the successful strategy according to the payoffs of the last round of the game, and then analyse the limiting distribution of the QBD process for the game stochastic evolutionary dynamic. The numerical experiments results are exhibited as pseudo colour ternary heat maps. Comparisons of these diagrams shows that the convergence property of long run equilibrium of the RSP game in populations depends on population size and the parameter of the payoff matrix and noise factor. The long run equilibrium is asymptotically stable, neutrally stable and unstable respectively according to the normalised parameters in the payoff matrix. Moreover, the results show that the distribution probability becomes more concentrated with a larger population size. This indicates that increasing the population size also increases the convergence speed of the stochastic evolution process while simultaneously reducing the influence of the noise factor.

  15. Sparse calibration of subsurface flow models using nonlinear orthogonal matching pursuit and an iterative stochastic ensemble method

    KAUST Repository

    Elsheikh, Ahmed H.

    2013-06-01

    We introduce a nonlinear orthogonal matching pursuit (NOMP) for sparse calibration of subsurface flow models. Sparse calibration is a challenging problem as the unknowns are both the non-zero components of the solution and their associated weights. NOMP is a greedy algorithm that discovers at each iteration the most correlated basis function with the residual from a large pool of basis functions. The discovered basis (aka support) is augmented across the nonlinear iterations. Once a set of basis functions are selected, the solution is obtained by applying Tikhonov regularization. The proposed algorithm relies on stochastically approximated gradient using an iterative stochastic ensemble method (ISEM). In the current study, the search space is parameterized using an overcomplete dictionary of basis functions built using the K-SVD algorithm. The proposed algorithm is the first ensemble based algorithm that tackels the sparse nonlinear parameter estimation problem. © 2013 Elsevier Ltd.

  16. A Stochastic Maximum Principle for a Stochastic Differential Game of a Mean-Field Type

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, John Joseph Absalom, E-mail: j.j.a.hosking@cma.uio.no [University of Oslo, Centre of Mathematics for Applications (CMA) (Norway)

    2012-12-15

    We construct a stochastic maximum principle (SMP) which provides necessary conditions for the existence of Nash equilibria in a certain form of N-agent stochastic differential game (SDG) of a mean-field type. The information structure considered for the SDG is of a possible asymmetric and partial type. To prove our SMP we take an approach based on spike-variations and adjoint representation techniques, analogous to that of S. Peng (SIAM J. Control Optim. 28(4):966-979, 1990) in the optimal stochastic control context. In our proof we apply adjoint representation procedures at three points. The first-order adjoint processes are defined as solutions to certain mean-field backward stochastic differential equations, and second-order adjoint processes of a first type are defined as solutions to certain backward stochastic differential equations. Second-order adjoint processes of a second type are defined as solutions of certain backward stochastic equations of a type that we introduce in this paper, and which we term conditional mean-field backward stochastic differential equations. From the resulting representations, we show that the terms relating to these second-order adjoint processes of the second type are of an order such that they do not appear in our final SMP equations. A comparable situation exists in an article by R. Buckdahn, B. Djehiche, and J. Li (Appl. Math. Optim. 64(2):197-216, 2011) that constructs a SMP for a mean-field type optimal stochastic control problem; however, the approach we take of using these second-order adjoint processes of a second type to deal with the type of terms that we refer to as the second form of quadratic-type terms represents an alternative to a development, to our setting, of the approach used in their article for their analogous type of term.

  17. A Stochastic Maximum Principle for a Stochastic Differential Game of a Mean-Field Type

    International Nuclear Information System (INIS)

    Hosking, John Joseph Absalom

    2012-01-01

    We construct a stochastic maximum principle (SMP) which provides necessary conditions for the existence of Nash equilibria in a certain form of N-agent stochastic differential game (SDG) of a mean-field type. The information structure considered for the SDG is of a possible asymmetric and partial type. To prove our SMP we take an approach based on spike-variations and adjoint representation techniques, analogous to that of S. Peng (SIAM J. Control Optim. 28(4):966–979, 1990) in the optimal stochastic control context. In our proof we apply adjoint representation procedures at three points. The first-order adjoint processes are defined as solutions to certain mean-field backward stochastic differential equations, and second-order adjoint processes of a first type are defined as solutions to certain backward stochastic differential equations. Second-order adjoint processes of a second type are defined as solutions of certain backward stochastic equations of a type that we introduce in this paper, and which we term conditional mean-field backward stochastic differential equations. From the resulting representations, we show that the terms relating to these second-order adjoint processes of the second type are of an order such that they do not appear in our final SMP equations. A comparable situation exists in an article by R. Buckdahn, B. Djehiche, and J. Li (Appl. Math. Optim. 64(2):197–216, 2011) that constructs a SMP for a mean-field type optimal stochastic control problem; however, the approach we take of using these second-order adjoint processes of a second type to deal with the type of terms that we refer to as the second form of quadratic-type terms represents an alternative to a development, to our setting, of the approach used in their article for their analogous type of term.

  18. Modeling and Computation of Transboundary Industrial Pollution with Emission Permits Trading by Stochastic Differential Game.

    Directory of Open Access Journals (Sweden)

    Shuhua Chang

    Full Text Available Transboundary industrial pollution requires international actions to control its formation and effects. In this paper, we present a stochastic differential game to model the transboundary industrial pollution problems with emission permits trading. More generally, the process of emission permits price is assumed to be stochastic and to follow a geometric Brownian motion (GBM. We make use of stochastic optimal control theory to derive the system of Hamilton-Jacobi-Bellman (HJB equations satisfied by the value functions for the cooperative and the noncooperative games, respectively, and then propose a so-called fitted finite volume method to solve it. The efficiency and the usefulness of this method are illustrated by the numerical experiments. The two regions' cooperative and noncooperative optimal emission paths, which maximize the regions' discounted streams of the net revenues, together with the value functions, are obtained. Additionally, we can also obtain the threshold conditions for the two regions to decide whether they cooperate or not in different cases. The effects of parameters in the established model on the results have been also examined. All the results demonstrate that the stochastic emission permits prices can motivate the players to make more flexible strategic decisions in the games.

  19. Complimentary Advanced Fusion Exploration

    National Research Council Canada - National Science Library

    Alford, Mark G; Jones, Eric C; Bubalo, Adnan; Neumann, Melissa; Greer, Michael J

    2005-01-01

    .... The focus areas were in the following regimes: multi-tensor homographic computer vision image fusion, out-of-sequence measurement and track data handling, Nash bargaining approaches to sensor management, pursuit-evasion game theoretic modeling...

  20. Tax Evasion, Information Reporting, and the Regressive Bias Prediction

    DEFF Research Database (Denmark)

    Boserup, Simon Halphen; Pinje, Jori Veng

    2013-01-01

    evasion and audit probabilities once we account for information reporting in the tax compliance game. When conditioning on information reporting, we find that both reduced-form evidence and simulations exhibit the predicted regressive bias. However, in the overall economy, this bias is negated by the tax......Models of rational tax evasion and optimal enforcement invariably predict a regressive bias in the effective tax system, which reduces redistribution in the economy. Using Danish administrative data, we show that a calibrated structural model of this type replicates moments and correlations of tax...

  1. The Linear Quadratic Gaussian Multistage Game with Nonclassical Information Pattern Using a Direct Solution Method

    Science.gov (United States)

    Clemens, Joshua William

    Game theory has application across multiple fields, spanning from economic strategy to optimal control of an aircraft and missile on an intercept trajectory. The idea of game theory is fascinating in that we can actually mathematically model real-world scenarios and determine optimal decision making. It may not always be easy to mathematically model certain real-world scenarios, nonetheless, game theory gives us an appreciation for the complexity involved in decision making. This complexity is especially apparent when the players involved have access to different information upon which to base their decision making (a nonclassical information pattern). Here we will focus on the class of adversarial two-player games (sometimes referred to as pursuit-evasion games) with nonclassical information pattern. We present a two-sided (simultaneous) optimization solution method for the two-player linear quadratic Gaussian (LQG) multistage game. This direct solution method allows for further interpretation of each player's decision making (strategy) as compared to previously used formal solution methods. In addition to the optimal control strategies, we present a saddle point proof and we derive an expression for the optimal performance index value. We provide some numerical results in order to further interpret the optimal control strategies and to highlight real-world application of this game-theoretic optimal solution.

  2. Bayesian analysis of deterministic and stochastic prisoner's dilemma games

    Directory of Open Access Journals (Sweden)

    Howard Kunreuther

    2009-08-01

    Full Text Available This paper compares the behavior of individuals playing a classic two-person deterministic prisoner's dilemma (PD game with choice data obtained from repeated interdependent security prisoner's dilemma games with varying probabilities of loss and the ability to learn (or not learn about the actions of one's counterpart, an area of recent interest in experimental economics. This novel data set, from a series of controlled laboratory experiments, is analyzed using Bayesian hierarchical methods, the first application of such methods in this research domain. We find that individuals are much more likely to be cooperative when payoffs are deterministic than when the outcomes are probabilistic. A key factor explaining this difference is that subjects in a stochastic PD game respond not just to what their counterparts did but also to whether or not they suffered a loss. These findings are interpreted in the context of behavioral theories of commitment, altruism and reciprocity. The work provides a linkage between Bayesian statistics, experimental economics, and consumer psychology.

  3. On Stochastic Fishery Games with Endogenous Stage-Payoffs and Transition Probabilities

    NARCIS (Netherlands)

    Joosten, Reinoud A.M.G.; Samuel, Llea; Li, Deng-Feng; Yang, Xiao-Guang; Uetz, Marc; Xu, Gen-Jiu

    2017-01-01

    We engineered a stochastic fishery game in which overfishing has a twofold effect: it gradually damages the fish stock inducing lower catches in states High and Low, and it gradually causes the system to spend more time in the latter state with lower landings. To analyze the effects of this ‘double

  4. Strategy Complexity of Finite-Horizon Markov Decision Processes and Simple Stochastic Games

    DEFF Research Database (Denmark)

    Ibsen-Jensen, Rasmus; Chatterjee, Krishnendu

    2012-01-01

    Markov decision processes (MDPs) and simple stochastic games (SSGs) provide a rich mathematical framework to study many important problems related to probabilistic systems. MDPs and SSGs with finite-horizon objectives, where the goal is to maximize the probability to reach a target state in a given...

  5. Nonzero-Sum Stochastic Differential Portfolio Games under a Markovian Regime Switching Model

    Directory of Open Access Journals (Sweden)

    Chaoqun Ma

    2015-01-01

    Full Text Available We consider a nonzero-sum stochastic differential portfolio game problem in a continuous-time Markov regime switching environment when the price dynamics of the risky assets are governed by a Markov-modulated geometric Brownian motion (GBM. The market parameters, including the bank interest rate and the appreciation and volatility rates of the risky assets, switch over time according to a continuous-time Markov chain. We formulate the nonzero-sum stochastic differential portfolio game problem as two utility maximization problems of the sum process between two investors’ terminal wealth. We derive a pair of regime switching Hamilton-Jacobi-Bellman (HJB equations and two systems of coupled HJB equations at different regimes. We obtain explicit optimal portfolio strategies and Feynman-Kac representations of the two value functions. Furthermore, we solve the system of coupled HJB equations explicitly in a special case where there are only two states in the Markov chain. Finally we provide comparative statics and numerical simulation analysis of optimal portfolio strategies and investigate the impact of regime switching on optimal portfolio strategies.

  6. Timing Tax Evasion

    OpenAIRE

    Dirk Niepelt

    2004-01-01

    Standard models of tax evasion implicitly assume that evasion is either fully detected, or not detected at all. Empirically, this is not the case, casting into doubt the traditional rationales for interior evasion choices. I propose two alternative, dynamic explanations for interior tax evasion rates: Fines depending on the duration of an evasion spell, and different vintages of income sources subject to aggregate risk and fixed costs when switched between evasion states. The dynamic approach...

  7. Sharpen customer service skills with PCRAFT Pursuit.

    Science.gov (United States)

    Dologite, Kimberly A; Willner, Kathleen C; Klepeiss, Debra J; York, Susan A; Cericola, Lisa M

    2003-01-01

    Traditional approaches to teaching customer service skills do not involve participant interaction, nor do they provide a fun and relaxed atmosphere for learning. This article describes the development of PCRAFT Pursuit, an innovative game used to teach customer service skills. The development process began with concerns identified through patient satisfaction surveys. The implementation of this game became an integral component of education to improve customer service skills of staff throughout the hospital network.

  8. Elements of Compared Law concerning Tax Evasion

    Directory of Open Access Journals (Sweden)

    Monica Pocora

    2015-08-01

    Full Text Available The resort to international tax evasion can be explained both through the game, often perverse, of the double taxation, due to the autonomy of the national fiscal regimes, as well as to the fiscal pressures deriving from these. In view of escaping to be subject to two different taxations, the taxpayer wishes actually to avoid them both. And in order to avoid being subject to either of them, he takes cover in the fiscally protected regions. The techniques are numerous and depend on the taxpayer’s imagination. They contain a series of subtle and agile combinations of using the disappearances between the fiscal systems by resorting sometimes to fraudulent mechanisms. This paper aims at analysing the European dimension of the evasion phenomenon, corresponding to some fiscal and social laws that are more favourable.

  9. Measurable Strategies in Differential Games

    Science.gov (United States)

    Ivanov, R. P.

    1990-02-01

    Nonlinear approach-evasion differential games are considered in which the initial data depend on the time. These games are investigated in the class of strategies that are functions of three variables, namely, the time, the phase variable, and the current value of the other player's control, and are measurable jointly with respect to the time and the phase variable. The ideas of the Pontryagin methods in differential games and Krasovskiĭ's ideas on extremal aiming are developed, and it is shown that measurable strategies have broad applicability. It is proved that measurable strategies are compatible with differential equations with discontinuous right-hand side, and general theorems on the existence of solving measurable strategies in approach-evasion problems are proved, along with some auxiliary assertions. It is shown that the saddle point condition in the small game ensures the existence of solving measurable strategies. An example is given. Bibliography: 14 titles.

  10. Stochastic gradient ascent outperforms gamers in the Quantum Moves game

    Science.gov (United States)

    Sels, Dries

    2018-04-01

    In a recent work on quantum state preparation, Sørensen and co-workers [Nature (London) 532, 210 (2016), 10.1038/nature17620] explore the possibility of using video games to help design quantum control protocols. The authors present a game called "Quantum Moves" (https://www.scienceathome.org/games/quantum-moves/) in which gamers have to move an atom from A to B by means of optical tweezers. They report that, "players succeed where purely numerical optimization fails." Moreover, by harnessing the player strategies, they can "outperform the most prominent established numerical methods." The aim of this Rapid Communication is to analyze the problem in detail and show that those claims are untenable. In fact, without any prior knowledge and starting from a random initial seed, a simple stochastic local optimization method finds near-optimal solutions which outperform all players. Counterdiabatic driving can even be used to generate protocols without resorting to numeric optimization. The analysis results in an accurate analytic estimate of the quantum speed limit which, apart from zero-point motion, is shown to be entirely classical in nature. The latter might explain why gamers are reasonably good at the game. A simple modification of the BringHomeWater challenge is proposed to test this hypothesis.

  11. Stochastic Stability in Internet Router Congestion Games

    Science.gov (United States)

    Chung, Christine; Pyrga, Evangelia

    Congestion control at bottleneck routers on the internet is a long standing problem. Many policies have been proposed for effective ways to drop packets from the queues of these routers so that network endpoints will be inclined to share router capacity fairly and minimize the overflow of packets trying to enter the queues. We study just how effective some of these queuing policies are when each network endpoint is a self-interested player with no information about the other players’ actions or preferences. By employing the adaptive learning model of evolutionary game theory, we study policies such as Droptail, RED, and the greedy-flow-punishing policy proposed by Gao et al. [10] to find the stochastically stable states: the states of the system that will be reached in the long run.

  12. Businessmen´s tax evasions

    OpenAIRE

    Karásková, Veronika

    2011-01-01

    The main goal of this bachelor thesis is categorize businessmen's tax evasions at personal income tax and find out their portion on total tax evasions. In the first chapter I focus on tax avoidance and tax evasion, causes of tax evasion and his measurement. Next parts of this thesis focus on businessmen's tax evasion at personal income tax. In the second part I describe some very frequented cases of tax evasions revealed by revenue authorities. In the last part I analyse these tax evasions, c...

  13. Application of differential game theory to role-determination in aerial combat

    Science.gov (United States)

    Merz, A. W.

    1975-01-01

    The development of criteria which specify the roles of pursuer and evader as functions of the relative geometry and of the important parameters of the problem are discussed. A reduced-order model of the relative motion is derived and discussed. In this model, the two aircraft move in the same plane at unequal but constant speeds, and with different maximum turn rates. The equations of relative motion are of third order, the dependent variables being the relative range, bearing, and heading of the two aircraft. Termination of the pursuit-evasion game is defined by either the heading-limited or the range-limited end condition. These are geometric conditions for which the evading aircraft is in front of the other, with the relative heading and relative range satisfying certain inequalities. Retrograde solutions to the equations of relative motion were used with the derived optimal terminal maneuvers to find where an assumed set of end conditions could have begun.

  14. Stereoscopic filming for investigating evasive side-stepping and anterior cruciate ligament injury risk

    Science.gov (United States)

    Lee, Marcus J. C.; Bourke, Paul; Alderson, Jacqueline A.; Lloyd, David G.; Lay, Brendan

    2010-02-01

    Non-contact anterior cruciate ligament (ACL) injuries are serious and debilitating, often resulting from the performance of evasive sides-stepping (Ssg) by team sport athletes. Previous laboratory based investigations of evasive Ssg have used generic visual stimuli to simulate realistic time and space constraints that athletes experience in the preparation and execution of the manoeuvre. However, the use of unrealistic visual stimuli to impose these constraints may not be accurately identifying the relationship between the perceptual demands and ACL loading during Ssg in actual game environments. We propose that stereoscopically filmed footage featuring sport specific opposing defender/s simulating a tackle on the viewer, when used as visual stimuli, could improve the ecological validity of laboratory based investigations of evasive Ssg. Due to the need for precision and not just the experience of viewing depth in these scenarios, a rigorous filming process built on key geometric considerations and equipment development to enable a separation of 6.5 cm between two commodity cameras had to be undertaken. Within safety limits, this could be an invaluable tool in enabling more accurate investigations of the associations between evasive Ssg and ACL injury risk.

  15. Mapping of the stochastic Lotka-Volterra model to models of population genetics and game theory

    Science.gov (United States)

    Constable, George W. A.; McKane, Alan J.

    2017-08-01

    The relationship between the M -species stochastic Lotka-Volterra competition (SLVC) model and the M -allele Moran model of population genetics is explored via timescale separation arguments. When selection for species is weak and the population size is large but finite, precise conditions are determined for the stochastic dynamics of the SLVC model to be mappable to the neutral Moran model, the Moran model with frequency-independent selection, and the Moran model with frequency-dependent selection (equivalently a game-theoretic formulation of the Moran model). We demonstrate how these mappings can be used to calculate extinction probabilities and the times until a species' extinction in the SLVC model.

  16. Tax Evasion and Inequality

    DEFF Research Database (Denmark)

    Alstadsæter, Annette; Johannesen, Niels; Zucman, Gabriel

    2017-01-01

    .01% of the wealth distribution, a group that includes households with more than $45 million in net wealth. A simple model of the supply of tax evasion services can explain why evasion rises steeply with wealth. Taking tax evasion into account increases the rise in inequality seen in tax data since the 1970s......This paper attempts to estimate the size and distribution of tax evasion in rich countries. We combine random audits—the key source used to study tax evasion so far—with new micro-data leaked from large offshore financial institutions—HSBC Switzerland (“Swiss leaks”) and Mossack Fonseca (“Panama...... Papers”)—matched to population-wide wealth records in Norway, Sweden, and Denmark. We find that tax evasion rises sharply with wealth, a phenomenon random audits fail to capture. On average about 3% of personal taxes are evaded in Scandinavia, but this figure rises to close to 30% in the top 0...

  17. Clockwork game design

    CERN Document Server

    Burgun, Keith

    2015-01-01

    Only by finding and focusing on a core mechanism can you further your pursuit of elegance in strategy game design.Clockwork Game Design is the most functional and directly applicable theory for game design. It details the clockwork game design pattern, which focuses on building around fundamental functionality. You can then use this understanding to prescribe a system for building and refining your rulesets. A game can achieve clarity of purpose by starting with a strong core, then removing elements that conflict with that core while adding elements that support it.Filled with examples and exe

  18. Differential games in economic systems with delays

    Science.gov (United States)

    Kim, A. V.; Kormyshev, V. M.; Novikov, M. Yu.; Nikonov, M. A.

    2017-11-01

    In the paper, we consider application of i-smooth analysis (A.V. Kim, 2015) to differential games with delays in economics (Dockner E.J., et all, 2000; R. Isaacs, 1999). The approach is developed in the framework of the theory of positional differential games (N.N. Krasovskii, A.I. Subbotin, 1988; A.V. Kryazhimskii, Yu.S. Osipov, 1973; Yu.S. Osipov, J. Appl. Math. Mech. Vol. 35, № 1, № 6, 1971) and is based on application of the extremal shift strategy. We consider basic notions and constructions of the approach-evasion problem for linear systems with delays. The necessary and sufficient conditions of solvability the approach-evasion problem in terms of special u-stable sets are presented in another paper.

  19. Some Analytical Properties of the Model for Stochastic Evolutionary Games in Finite Populations with Non-uniform Interaction Rate

    International Nuclear Information System (INIS)

    Quan Ji; Wang Xianjia

    2013-01-01

    Traditional evolutionary games assume uniform interaction rate, which means that the rate at which individuals meet and interact is independent of their strategies. But in some systems, especially biological systems, the players interact with each other discriminately. Taylor and Nowak (2006) were the first to establish the corresponding non-uniform interaction rate model by allowing the interaction rates to depend on strategies. Their model is based on replicator dynamics which assumes an infinite size population. But in reality, the number of individuals in the population is always finite, and there will be some random interference in the individuals' strategy selection process. Therefore, it is more practical to establish the corresponding stochastic evolutionary model in finite populations. In fact, the analysis of evolutionary games in a finite size population is more difficult. Just as Taylor and Nowak said in the outlook section of their paper, ''The analysis of non-uniform interaction rates should be extended to stochastic game dynamics of finite populations''. In this paper, we are exactly doing this work. We extend Taylor and Nowak's model from infinite to finite case, especially focusing on the infiuence of non-uniform connection characteristics on the evolutionary stable state of the system. We model the strategy evolutionary process of the population by a continuous ergodic Markov process. Based on the limit distribution of the process, we can give the evolutionary stable state of the system. We make a complete classification of the symmetric 2 × 2 games. For each case game, the corresponding limit distribution of the Markov-based process is given when noise intensity is small enough. In contrast with most literatures in evolutionary games using the simulation method, all our results obtained are analytical. Especially, in the dominant-case game, coexistence of the two strategies may become evolutionary stable states in our model. This result can be

  20. A New Approach of Multi-robot Cooperative Pursuit Based on Association Rule Data Mining

    Directory of Open Access Journals (Sweden)

    Jun Li

    2010-02-01

    Full Text Available An approach of cooperative hunting for multiple mobile targets by multi-robot is presented, which divides the pursuit process into forming the pursuit teams and capturing the targets. The data sets of attribute relationship is built by consulting all of factors about capturing evaders, then the interesting rules can be found by data mining from the data sets to build the pursuit teams. Through doping out the positions of targets, the pursuit game can be transformed into multi-robot path planning. Reinforcement learning is used to find the best path. The simulation results show that the mobile evaders can be captured effectively and efficiently, and prove the feasibility and validity of the given algorithm under a dynamic environment.

  1. A New Approach of Multi-Robot Cooperative Pursuit Based on Association Rule Data Mining

    Directory of Open Access Journals (Sweden)

    Jun Li

    2009-12-01

    Full Text Available An approach of cooperative hunting for multiple mobile targets by multi-robot is presented, which divides the pursuit process into forming the pursuit teams and capturing the targets. The data sets of attribute relationship is built by consulting all of factors about capturing evaders, then the interesting rules can be found by data mining from the data sets to build the pursuit teams. Through doping out the positions of targets, the pursuit game can be transformed into multi-robot path planning. Reinforcement learning is used to find the best path. The simulation results show that the mobile evaders can be captured effectively and efficiently, and prove the feasibility and validity of the given algorithm under a dynamic environment.

  2. Randomized Prediction Games for Adversarial Machine Learning.

    Science.gov (United States)

    Rota Bulo, Samuel; Biggio, Battista; Pillai, Ignazio; Pelillo, Marcello; Roli, Fabio

    In spam and malware detection, attackers exploit randomization to obfuscate malicious data and increase their chances of evading detection at test time, e.g., malware code is typically obfuscated using random strings or byte sequences to hide known exploits. Interestingly, randomization has also been proposed to improve security of learning algorithms against evasion attacks, as it results in hiding information about the classifier to the attacker. Recent work has proposed game-theoretical formulations to learn secure classifiers, by simulating different evasion attacks and modifying the classification function accordingly. However, both the classification function and the simulated data manipulations have been modeled in a deterministic manner, without accounting for any form of randomization. In this paper, we overcome this limitation by proposing a randomized prediction game, namely, a noncooperative game-theoretic formulation in which the classifier and the attacker make randomized strategy selections according to some probability distribution defined over the respective strategy set. We show that our approach allows one to improve the tradeoff between attack detection and false alarms with respect to the state-of-the-art secure classifiers, even against attacks that are different from those hypothesized during design, on application examples including handwritten digit recognition, spam, and malware detection.In spam and malware detection, attackers exploit randomization to obfuscate malicious data and increase their chances of evading detection at test time, e.g., malware code is typically obfuscated using random strings or byte sequences to hide known exploits. Interestingly, randomization has also been proposed to improve security of learning algorithms against evasion attacks, as it results in hiding information about the classifier to the attacker. Recent work has proposed game-theoretical formulations to learn secure classifiers, by simulating different

  3. Using Computer Games for Instruction: The Student Experience

    Science.gov (United States)

    Grimley, Michael; Green, Richard; Nilsen, Trond; Thompson, David; Tomes, Russell

    2011-01-01

    Computer games are fun, exciting and motivational when used as leisure pursuits. But do they have similar attributes when utilized for educational purposes? This article investigates whether learning by computer game can improve student experiences compared with a more formal lecture approach and whether computer games have potential for improving…

  4. The sweetness of successful goal pursuit: Approach-motivated pregoal states enhance the reward positivity during goal pursuit.

    Science.gov (United States)

    Threadgill, A Hunter; Gable, Philip A

    2017-12-21

    Traditionally, the reward positivity (RewP) is thought to index a binary performance monitoring system sensitive to approach motivation. However, recent theoretical models have argued that feedback processing extends beyond simple "good" vs. "bad" associations, such that performance monitoring incorporates the complex, multi-step sequence of behaviors often necessary to attain rewards. The present study sought to go beyond simple stimulus-response paradigms to examine how approach-motivated states occurring in multi-step goal pursuit impacts the RewP. Additionally, outcome frequency was varied to examine how the P3, a neural marker of expectancy, influences the RewP. Using a modified monetary incentive delay paradigm, participants played a reaction time game where multiple correct responses were required to attain a reward. Additionally, each trial had the potential for a reward (approach-motivated state) or no reward (neutral state). Results revealed that RewP amplitudes were larger after reward trial win feedback than after reward trial no-win feedback across multiple stages of goal pursuit. Additionally, after for controlling outcome frequency via the P3, RewP amplitudes were larger in reward trials than in neutral trials across incremental stages of goal pursuit. The RewP appears to be sensitive to feedback indicating successfully completing sub-goals during pursuit of a goal, even when no immediate reward is given. Approach motivation enhances performance monitoring when multiple steps are needed to attain a desired outcome, which may increase the likelihood of goal acquisition and attainment. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. 15 CFR 760.4 - Evasion.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Evasion. 760.4 Section 760.4 Commerce... BOYCOTTS § 760.4 Evasion. (a) No United States person may engage in any transaction or take any other... the coverage and intent of the exceptions set forth in this part do not constitute evasion regardless...

  6. Deciding on Tax Evasion

    DEFF Research Database (Denmark)

    Boll, Karen

    2015-01-01

    Purpose – The purpose of this paper is to analyse everyday reasoning in public administration. This is done by focusing on front line tax inspectors’ decisions about tax evasion. Design/methodology/approach – The paper presents ethnography of bureaucracy and field audits. The material stems from...... fieldwork conducted in the Central Customs and Tax Administration. Findings – The paper shows that the tax inspectors reason about tax evasion in a casuistic manner. They pay attention to similar cases and to particular circumstances of the individual cases. In deciding on tax evasion, the inspectors do...

  7. Mean-Potential Law in Evolutionary Games

    Science.gov (United States)

    Nałecz-Jawecki, Paweł; Miekisz, Jacek

    2018-01-01

    The Letter presents a novel way to connect random walks, stochastic differential equations, and evolutionary game theory. We introduce a new concept of a potential function for discrete-space stochastic systems. It is based on a correspondence between one-dimensional stochastic differential equations and random walks, which may be exact not only in the continuous limit but also in finite-state spaces. Our method is useful for computation of fixation probabilities in discrete stochastic dynamical systems with two absorbing states. We apply it to evolutionary games, formulating two simple and intuitive criteria for evolutionary stability of pure Nash equilibria in finite populations. In particular, we show that the 1 /3 law of evolutionary games, introduced by Nowak et al. [Nature, 2004], follows from a more general mean-potential law.

  8. Steering and evasion assist

    NARCIS (Netherlands)

    Dang, T.; Desens, J.; Franke, U.; Gavrila, D.; Schäfers, L.; Ziegler, W.; Eskandarian, A.

    2012-01-01

    Steering and evasion assistance defines a new and future class of driver assistance systems to avoid an impending collision with other traffic participants. Dynamic and kinematic considerations reveal that an evasive steering maneuver has high potential for collision avoidance in many driving

  9. Governance Mechanism for Global Greenhouse Gas Emissions: A Stochastic Differential Game Approach

    Directory of Open Access Journals (Sweden)

    Wei Yu

    2013-01-01

    Full Text Available Today developed and developing countries have to admit the fact that global warming is affecting the earth, but the fundamental problem of how to divide up necessary greenhouse gas reductions between developed and developing countries remains. In this paper, we propose cooperative and noncooperative stochastic differential game models to describe greenhouse gas emissions decision makings of developed and developing countries, calculate their feedback Nash equilibrium and the Pareto optimal solution, characterize parameter spaces that developed and developing countries can cooperate, design cooperative conditions under which participants buy the cooperative payoff, and distribute the cooperative payoff with Nash bargaining solution. Lastly, numerical simulations are employed to illustrate the above results.

  10. Analysis for Ad Hoc Network Attack-Defense Based on Stochastic Game Model

    Directory of Open Access Journals (Sweden)

    Yuanjie LI

    2014-06-01

    Full Text Available The attack actions analysis for Ad Hoc networks can provide a reference for the design security mechanisms. This paper presents an analysis method of security of Ad Hoc networks based on Stochastic Game Nets (SGN. This method can establish a SGN model of Ad Hoc networks and calculate to get the Nash equilibrium strategy. After transforming the SGN model into a continuous-time Markov Chain (CTMC, the security of Ad Hoc networks can be evaluated and analyzed quantitatively by calculating the stationary probability of CTMC. Finally, the Matlab simulation results show that the probability of successful attack is related to the attack intensity and expected payoffs, but not attack rate.

  11. Hypothalamic Circuits for Predation and Evasion.

    Science.gov (United States)

    Li, Yi; Zeng, Jiawei; Zhang, Juen; Yue, Chenyu; Zhong, Weixin; Liu, Zhixiang; Feng, Qiru; Luo, Minmin

    2018-02-21

    The interactions between predator and prey represent some of the most dramatic events in nature and constitute a matter of life and death for both sides. The hypothalamus has been implicated in driving predation and evasion; however, the exact hypothalamic neural circuits underlying these behaviors remain poorly defined. Here, we demonstrate that inhibitory and excitatory projections from the mouse lateral hypothalamus (LH) to the periaqueductal gray (PAG) in the midbrain drive, respectively, predation and evasion. LH GABA neurons were activated during predation. Optogenetically stimulating PAG-projecting LH GABA neurons drove strong predatory attack, and inhibiting these cells reversibly blocked predation. In contrast, LH glutamate neurons were activated during evasion. Stimulating PAG-projecting LH glutamate neurons drove evasion and inhibiting them impeded predictive evasion. Therefore, the seemingly opposite behaviors of predation and evasion are tightly regulated by two dissociable modular command systems within a single neural projection from the LH to the PAG. VIDEO ABSTRACT. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Tax Evasion in a Model of Endogenous Growth

    OpenAIRE

    Been-Lon Chen

    2003-01-01

    This paper integrates tax evasion into a standard AK growth model with public capital. In the model, the government optimizes the tax rate, while individuals optimize tax evasion. It studies tax rate, tax evasion and economic growth, and compares them with otherwise identical economies except those without tax evasion. It inquires into the effects of three government policies on tax rate, tax evasion, and economic growth. It finds that an increase in both unit cost of tax evasion and punishme...

  13. Tabletop Games: Platforms, Experimental Games and Design Recommendations

    Science.gov (United States)

    Haller, Michael; Forlines, Clifton; Koeffel, Christina; Leitner, Jakob; Shen, Chia

    While the last decade has seen massive improvements in not only the rendering quality, but also the overall performance of console and desktop video games, these improvements have not necessarily led to a greater population of video game players. In addition to continuing these improvements, the video game industry is also constantly searching for new ways to convert non-players into dedicated gamers. Despite the growing popularity of computer-based video games, people still love to play traditional board games, such as Risk, Monopoly, and Trivial Pursuit. Both video and board games have their strengths and weaknesses, and an intriguing conclusion is to merge both worlds. We believe that a tabletop form-factor provides an ideal interface for digital board games. The design and implementation of tabletop games will be influenced by the hardware platforms, form factors, sensing technologies, as well as input techniques and devices that are available and chosen. This chapter is divided into three major sections. In the first section, we describe the most recent tabletop hardware technologies that have been used by tabletop researchers and practitioners. In the second section, we discuss a set of experimental tabletop games. The third section presents ten evaluation heuristics for tabletop game design.

  14. TAX EVASION BETWEEN FRAUD AND OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    Emilia Cornelia STOICA

    2017-05-01

    Full Text Available Tax optimization, often called legal tax evasion is the use of methods and techniques that are within the law, in order to reduce or even cancel the tax liability. To achieve such an approach, the taxpayer or his advisers must know in depth the tax law - and by extension, the financial and administrative law - and, moreover, must be functional tax jurisdictions which allow the use of appropriate assemblies. The recent leasks, as WikiLeaks, LuxLeaks, SwissLeaks, Panama Papers etc. on financial flows to tax havens highlight the far-reaching unprecedented evasion and tax fraud, both in the amounts involved - trillions of dollars - and sophisticated assemblies used primarily by multinational companies to the detriment of the public finances of Member territory headquarters and branches which are located and, therefore, detrimental economic and social life of those countries. Tax evasion is based on legal mechanisms which, combined together in the montages of increasingly complex, allowing operators, mostly multinational legal entities to circumvent national tax law and not pay the taxes due. The border between tax optimization, tax evasion and fraud is very thin, optimization using various legal methods to reduce the tax owed, whereas tax evasion using illegal means, which covered crime. Tax evasion reveals either optimize or fraud. There is a significant international dimension of tax evasion because it is favored by multinational corporations operating conditions.

  15. Energetics and evasion dynamics of large predators and prey: pumas vs. hounds.

    Science.gov (United States)

    Bryce, Caleb M; Wilmers, Christopher C; Williams, Terrie M

    2017-01-01

    Quantification of fine-scale movement, performance, and energetics of hunting by large carnivores is critical for understanding the physiological underpinnings of trophic interactions. This is particularly challenging for wide-ranging terrestrial canid and felid predators, which can each affect ecosystem structure through distinct hunting modes. To compare free-ranging pursuit and escape performance from group-hunting and solitary predators in unprecedented detail, we calibrated and deployed accelerometer-GPS collars during predator-prey chase sequences using packs of hound dogs ( Canis lupus familiaris , 26 kg, n  = 4-5 per chase) pursuing simultaneously instrumented solitary pumas ( Puma concolor , 60 kg, n  = 2). We then reconstructed chase paths, speed and turning angle profiles, and energy demands for hounds and pumas to examine performance and physiological constraints associated with cursorial and cryptic hunting modes, respectively. Interaction dynamics revealed how pumas successfully utilized terrain (e.g., fleeing up steep, wooded hillsides) as well as evasive maneuvers (e.g., jumping into trees, running in figure-8 patterns) to increase their escape distance from the overall faster hounds (avg. 2.3× faster). These adaptive strategies were essential to evasion in light of the mean 1.6× higher mass-specific energetic costs of the chase for pumas compared to hounds (mean: 0.76 vs. 1.29 kJ kg -1  min -1 , respectively). On an instantaneous basis, escapes were more costly for pumas, requiring exercise at ≥90% of predicted [Formula: see text] and consuming as much energy per minute as approximately 5 min of active hunting. Our results demonstrate the marked investment of energy for evasion by a large, solitary carnivore and the advantage of dynamic maneuvers to postpone being overtaken by group-hunting canids.

  16. Energetics and evasion dynamics of large predators and prey: pumas vs. hounds

    Directory of Open Access Journals (Sweden)

    Caleb M. Bryce

    2017-08-01

    Full Text Available Quantification of fine-scale movement, performance, and energetics of hunting by large carnivores is critical for understanding the physiological underpinnings of trophic interactions. This is particularly challenging for wide-ranging terrestrial canid and felid predators, which can each affect ecosystem structure through distinct hunting modes. To compare free-ranging pursuit and escape performance from group-hunting and solitary predators in unprecedented detail, we calibrated and deployed accelerometer-GPS collars during predator-prey chase sequences using packs of hound dogs (Canis lupus familiaris, 26 kg, n = 4–5 per chase pursuing simultaneously instrumented solitary pumas (Puma concolor, 60 kg, n = 2. We then reconstructed chase paths, speed and turning angle profiles, and energy demands for hounds and pumas to examine performance and physiological constraints associated with cursorial and cryptic hunting modes, respectively. Interaction dynamics revealed how pumas successfully utilized terrain (e.g., fleeing up steep, wooded hillsides as well as evasive maneuvers (e.g., jumping into trees, running in figure-8 patterns to increase their escape distance from the overall faster hounds (avg. 2.3× faster. These adaptive strategies were essential to evasion in light of the mean 1.6× higher mass-specific energetic costs of the chase for pumas compared to hounds (mean: 0.76 vs. 1.29 kJ kg−1 min−1, respectively. On an instantaneous basis, escapes were more costly for pumas, requiring exercise at ≥90% of predicted $\\dot {\\mathrm{V }}{\\mathrm{O}}_{2\\mathrm{MAX}}$ V ̇ O 2 MAX and consuming as much energy per minute as approximately 5 min of active hunting. Our results demonstrate the marked investment of energy for evasion by a large, solitary carnivore and the advantage of dynamic maneuvers to postpone being overtaken by group-hunting canids.

  17. Bureaucratic Corruption and Profit Tax Evasion

    OpenAIRE

    Laszlo Goerke

    2006-01-01

    Firms may evade taxes on profits and can also avoid fulfilling legal restrictions on production activities by bribing bureaucrats. It is shown that the existence of tax evasion does not affect corruption activities at the firm level, while the budgetary repercussions of tax evasion induce less corruption. Policy measures which alter the gains or losses from corruption have a non-systematic impact on tax evasion behaviour.

  18. Deterministic Graphical Games Revisited

    DEFF Research Database (Denmark)

    Andersson, Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro

    2008-01-01

    We revisit the deterministic graphical games of Washburn. A deterministic graphical game can be described as a simple stochastic game (a notion due to Anne Condon), except that we allow arbitrary real payoffs but disallow moves of chance. We study the complexity of solving deterministic graphical...... games and obtain an almost-linear time comparison-based algorithm for computing an equilibrium of such a game. The existence of a linear time comparison-based algorithm remains an open problem....

  19. Statistical mechanics of spatial evolutionary games

    International Nuclear Information System (INIS)

    Miekisz, Jacek

    2004-01-01

    We discuss the long-run behaviour of stochastic dynamics of many interacting players in spatial evolutionary games. In particular, we investigate the effect of the number of players and the noise level on the stochastic stability of Nash equilibria. We discuss similarities and differences between systems of interacting players maximizing their individual payoffs and particles minimizing their interaction energy. We use concepts and techniques of statistical mechanics to study game-theoretic models. In order to obtain results in the case of the so-called potential games, we analyse the thermodynamic limit of the appropriate models of interacting particles

  20. A class of stochastic games with infinitely many interacting agents related to Glauber dynamics on random graphs

    International Nuclear Information System (INIS)

    De Santis, Emilio; Marinelli, Carlo

    2007-01-01

    We introduce and study a class of infinite-horizon non-zero-sum non-cooperative stochastic games with infinitely many interacting agents using ideas of statistical mechanics. First we show, in the general case of asymmetric interactions, the existence of a strategy that allows any player to eliminate losses after a finite random time. In the special case of symmetric interactions, we also prove that, as time goes to infinity, the game converges to a Nash equilibrium. Moreover, assuming that all agents adopt the same strategy, using arguments related to those leading to perfect simulation algorithms, spatial mixing and ergodicity are proved. In turn, ergodicity allows us to prove 'fixation', i.e. players will adopt a constant strategy after a finite time. The resulting dynamics is related to zero-temperature Glauber dynamics on random graphs of possibly infinite volume

  1. Evolutionary stability concepts in a stochastic environment

    Science.gov (United States)

    Zheng, Xiu-Deng; Li, Cong; Lessard, Sabin; Tao, Yi

    2017-09-01

    Over the past 30 years, evolutionary game theory and the concept of an evolutionarily stable strategy have been not only extensively developed and successfully applied to explain the evolution of animal behaviors, but also widely used in economics and social sciences. Nonetheless, the stochastic dynamical properties of evolutionary games in randomly fluctuating environments are still unclear. In this study, we investigate conditions for stochastic local stability of fixation states and constant interior equilibria in a two-phenotype model with random payoffs following pairwise interactions. Based on this model, we develop the concepts of stochastic evolutionary stability (SES) and stochastic convergence stability (SCS). We show that the condition for a pure strategy to be SES and SCS is more stringent than in a constant environment, while the condition for a constant mixed strategy to be SES is less stringent than the condition to be SCS, which is less stringent than the condition in a constant environment.

  2. Strategy iteration is strongly polynomial for 2-player turn-based stochastic games with a constant discount factor

    DEFF Research Database (Denmark)

    Hansen, Thomas Dueholm; Miltersen, Peter Bro; Zwick, Uri

    2011-01-01

    Ye showed recently that the simplex method with Dantzig pivoting rule, as well as Howard's policy iteration algorithm, solve discounted Markov decision processes (MDPs), with a constant discount factor, in strongly polynomial time. More precisely, Ye showed that both algorithms terminate after...... iterations. Second, and more importantly, we show that the same bound applies to the number of iterations performed by the strategy iteration (or strategy improvement) algorithm, a generalization of Howard's policy iteration algorithm used for solving 2-player turn-based stochastic games with discounted zero...

  3. Tax evasion and the law in Nigeria

    Directory of Open Access Journals (Sweden)

    Enya Matthew Nwocha

    2017-12-01

    Full Text Available This paper has dealt with the incidence of tax evasion and how the law in Nigeria has tackled the problem. It came against the background of massive tax evasion in the country which has resulted in the loss of needed revenue for development. Most individuals eligible to pay tax are not usually amenable to doing so willingly thereby resulting in tax evasion and tax avoidance. Neglect or refusal to pay tax invariably attracts various ranges of punishment. All of these issues have been discussed in this paper under introduction, conceptual framework, grounds for imposition of tax, statutory provisions on tax evasion, reasons for and implications of tax evasion, recommendations and conclusion. The paper in discussing the subject has focused on the principal tax legislations in the country, namely, the Personal Income Tax Act, Companies Income Tax Act, and the Federal Inland Revenue Service Act.

  4. VAT EVASION INLEBANON: CASES AND MAIN CAUSES

    Directory of Open Access Journals (Sweden)

    Rana Ismail

    2012-07-01

    Full Text Available The Value Added Tax (VAT is a very important source oftreasuryrevenuesinLebanon. It was initially introduced inLebanon in order to reduce the budgetdeficit and help contain the debt. However, VAT evasion growth inLebanon isleading to significant VAT revenue losses because of its size and frequency.In this paper, we will highlight the contribution of VAT to the treasury revenue. Inaddition, our research has led to figure out the most significant VAT evasion casesand the way tax payers evade paying their required VAT or try to have an illegalrefund. From these tax evasion cases, we will pinpoint the main causes of suchevasions and propose solutions to limit as much as possible VAT evasion inLebanon.

  5. Players' expertise and competition with others shape the satisfaction of competence needs, gaming gratifications, and contingent self-esteem in a gaming context.

    Science.gov (United States)

    Kazakova, Snezhanka; Cauberghe, Veroline; Pandelaere, Mario; De Pelsmacker, Patrick

    2014-01-01

    The current study explores how competition and gaming expertise affect the satisfaction of competence needs and gaming gratifications. We demonstrate that competition moderates the effect of gaming expertise on the satisfaction of competence needs, which in turn affects game enjoyment and replay intention. Gaming expertise predicted players' need satisfaction, game enjoyment, and replay intention significantly better in a competitive compared to a noncompetitive context. The effect of gaming expertise on game enjoyment and replay intention was, furthermore, mediated by the satisfaction of competence needs. Finally, gaming expertise positively affected the importance of competition for players' self-esteem only in the competitive gaming context. The present findings demonstrate the importance of competition and gaming expertise for the satisfaction of competence needs, gaming gratifications, and the pursuit of self-esteem during gameplay, attesting to the applicability of self-determination theory to gaming contexts.

  6. TAX EVASION THROUGH FICTITIOUS ECONOMIC OPERATIONS, OBSTACLE TO SUSTAINABLE DEVELOPMENT

    OpenAIRE

    SERGIU-BOGDAN CONSTANTIN

    2016-01-01

    Tax evasion means the avoidance of declaring and paying taxes. The purpose of the research is to identify ways and mechanisms of tax evasion through fictitious economic operations and how this kind o tax evasion can influence sustainable development. The principal methods are researching tax evasion cases investigated by the Romanian authorities responsible for combating this phenomenon, court trials on tax evasion and using the bibliographic references in the field. The data used...

  7. Study of seismological evasion. Part III. Evaluation of evasion possibilities using codas of large earthquakes

    International Nuclear Information System (INIS)

    Evernden, J.F.

    1976-01-01

    The seismological aspects of various proposed means of obscuring or hiding the seismic signatures of explosions from a surveillance network are discussed. These so-called evasion schemes are discussed from the points of view of both the evader and the monitor. The analysis will be conducted in terms of the USSR solely because that country is so vast and the geological/geophysical complexities of the country are so great that the complete spectrum of hypothesized evasion schemes requires discussion. Techniques appropriate for use when the seismic noise problem is interference due to codas of P and surface waves from earthquakes are described, and the capabilities of several seismological networks to restrain use of such codas for effective evasion are analyzed

  8. Senior Games as Serious Sport Tourism

    Science.gov (United States)

    Heo, Jimmoo; King, Carina

    2009-01-01

    Stebbins (1992) defined serious leisure as the systematic pursuit of amateur, hobbyist, or volunteer activity that is substantial and interesting for the participants involved. This study investigated associations between serious leisure and sport tourism using Indiana Senior Games participants. This study used a self-report questionnaire to…

  9. Tax Evasion Dynamics in Romania Reflected by Fiscal Inspection Activities

    Directory of Open Access Journals (Sweden)

    CORINA-MARIA ENE

    2010-06-01

    Full Text Available The paper aims to provide a panoramic view of the dynamics of tax evasion in Romania, reflected in terms of fiscal inspection activities. The author used the official data published by the institutions with attributions on the line of identification and fighting against tax evasion (National Agency of Fiscal Administration and Financial Guard with the view to reflect the real situation concerning the number of inspections, quantify and sanction tax evasion for 2003-2008 periods. Although the number of fiscal inspections and the number of tax payers who have violated the rules of fiscal discipline decreased compared with 2003, the frequency of tax evasion remained. At the same time, based on the data referring to the level and dynamics of the tax dodger phenomenon appreciations have been made regarding the fiscal discipline of the Romanian tax payer and to the attitude of the qualified institutions in discovering and sanctioning the fraudulent tax evasion. In this respect, the author observed that the level of willingness of tax legislation in relation to the Romanian tax payer has not changed considerably.The level of identified tax evasion reported to real GDP increased slightly. This situation can be interpreted as a success of institutions in charge of identification and fighting of tax evasion, a result of the increase of fiscal inspection number and detection probability, but also a result of GDP growth at a rate lower than the identified tax evasion. The author has also tried to find a causality relation between the option for tax evasion and corruption. The author found that a corrupt environment facilitates the decision to evade depending on detection probability, penalty system and bribery level as discouraging factors for tax evasion. The level of identified tax evasion is smaller than the real level of entire tax evasion, an important part being impossible to determine because of corruption.

  10. The Hidden Costs of Tax Evasion: Collaborative Tax Evasion in Markets for Expert Services

    OpenAIRE

    Balafoutas, Loukas; Beck, Adrian; Kerschbamer, Rudolf; Sutter, Matthias

    2015-01-01

    We experimentally examine the impact of tax evasion attempts on the performance of credence goods markets, where contractual incompleteness results from asymmetric information on the welfare maximizing quality of the good. Our results suggest that tax evasion attempts – independently of whether they are successful or not – lead to efficiency losses in the form of too low quality and less frequent trade. Thus, shadow economies may reduce welfare not only by inducing agents to incur costs to hi...

  11. Utilizing Video Games

    Science.gov (United States)

    Blaize, L.

    Almost from its birth, the computer and video gaming industry has done an admirable job of communicating the vision and attempting to convey the experience of traveling through space to millions of gamers from all cultures and demographics. This paper will propose several approaches the 100 Year Starship Study can take to use the power of interactive media to stir interest in the Starship and related projects among a global population. It will examine successful gaming franchises from the past that are relevant to the mission and consider ways in which the Starship Study could cooperate with game development studios to bring the Starship vision to those franchises and thereby to the public. The paper will examine ways in which video games can be used to crowd-source research aspects for the Study, and how video games are already considering many of the same topics that will be examined by this Study. Finally, the paper will propose some mechanisms by which the 100 Year Starship Study can establish very close ties with the gaming industry and foster cooperation in pursuit of the Study's goals.

  12. TAX EVASION THROUGH FICTITIOUS ECONOMIC OPERATIONS, OBSTACLE TO SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    SERGIU-BOGDAN CONSTANTIN

    2016-06-01

    Full Text Available Tax evasion means the avoidance of declaring and paying taxes. The purpose of the research is to identify ways and mechanisms of tax evasion through fictitious economic operations and how this kind o tax evasion can influence sustainable development. The principal methods are researching tax evasion cases investigated by the Romanian authorities responsible for combating this phenomenon, court trials on tax evasion and using the bibliographic references in the field. The data used are obtained through open sources of the authorities specialized in combating tax evasion for the cases made public, the media and also from specialised literature. The principal results are that this type of tax evasion is manifested through transactions with “ghost companies”, with offshore companies and transactions between associated enterprises. The main causes of this problem are: high taxation, corruption, inefficient government and tax authorities, no fiscal education and very hard tax legislation. The consequences are that the state budget is affected, the companies that do business legally are affected and also the final consumers, so Romania will not have economic growth and the quality of life will not improve. The main conclusion is that in order to have sustainable development, tax evasion in general and this kind of tax evasion in particular must be eradicated. The measures that have to be taken are to prevent tax evasion and to tighten controls but without violating taxpayers rights and without making abuses

  13. Tax evasion, social norms and economic growth

    OpenAIRE

    Bethencourt, Carlos; Kunze, Lars

    2013-01-01

    This paper proposes a theoretical model to account for the most relevant micro- and macroeconomic empirical facts in the tax evasion literature. To do so, we integrate tax morale into a dynamic overlapping generations model of capital income tax evasion. Tax morale is modeled as a social norm for tax compliance. It is shown that accounting for such nonpecuniary costs of evasion may not only explain (i) why some taxpayers never evade even if the gamble is profitable, and (ii) how a higher tax ...

  14. Host-pathogen interactions between the human innate immune system and Candida albicans - Understanding and modeling defense and evasion strategies

    Directory of Open Access Journals (Sweden)

    Sybille eDühring

    2015-06-01

    Full Text Available The diploid, polymorphic yeast Candida albicans is one of the most important humanpathogenic fungi. C. albicans can grow, proliferate and coexist as a commensal on or within thehuman host for a long time. Alterations in the host environment, however, can render C. albicansvirulent. In this review, we describe the immunological cross-talk between C. albicans and thehuman innate immune system. We give an overview in form of pairs of human defense strategiesincluding immunological mechanisms as well as general stressors such as nutrient limitation,pH, fever etc. and the corresponding fungal response and evasion mechanisms. FurthermoreComputational Systems Biology approaches to model and investigate these complex interactionare highlighted with a special focus on game-theoretical methods and agent-based models. Anoutlook on interesting questions to be tackled by Systems Biology regarding entangled defenseand evasion mechanisms is given.

  15. Stochastic evolutionary dynamics in minimum-effort coordination games

    Science.gov (United States)

    Li, Kun; Cong, Rui; Wang, Long

    2016-08-01

    The minimum-effort coordination game draws recently more attention for the fact that human behavior in this social dilemma is often inconsistent with the predictions of classical game theory. Here, we combine evolutionary game theory and coalescence theory to investigate this game in finite populations. Both analytic results and individual-based simulations show that effort costs play a key role in the evolution of contribution levels, which is in good agreement with those observed experimentally. Besides well-mixed populations, set structured populations have also been taken into consideration. Therein we find that large number of sets and moderate migration rate greatly promote effort levels, especially for high effort costs.

  16. THE DETERMINANTS PERCEPTION OF TAX EVASION ETHICS

    Directory of Open Access Journals (Sweden)

    Ningsih D.N.C.

    2018-01-01

    Full Text Available This study aimed to examine the determinants perception of tax evasion ethics, and combined three models based on the research of McGee et al (2012, Lau et al (2013, Lemvora et al (2013. Data collection used survey method on 148 auditors who worked at Public Accountant Office (KAP Big Ten. The result of this study showed that the justice and taxation systems affect significantly negative toward the perception of tax evasion ethics. Religiosity strengthened the effect of justice, taxation systems, and discrimination on the perception of tax evasion ethics.

  17. The influence of deterministic and stochastic waiting time for triggering mortality and colonization events on the coexistence of cooperators and defectors in an evolutionary game model

    Directory of Open Access Journals (Sweden)

    YouHua Chen

    2014-06-01

    Full Text Available In the present report, the coexistence of Prisoners' Dilemma game players (cooperators and defectors were explored in an individual-based framework with the consideration of the impacts of deterministic and stochastic waiting time (WT for triggering mortality and/or colonization events. For the type of deterministic waiting time, the time step for triggering a mortality and/or colonization event is fixed. For the type of stochastic waiting time, whether a mortality and/or colonization event should be triggered for each time step of a simulation is randomly determined by a given acceptance probability (the event takes place when a variate drawn from a uniform distribution [0,1] is smaller than the acceptance probability. The two strategies of modeling waiting time are considered simultaneously and applied to both quantities (mortality: WTm, colonization: WTc. As such, when WT (WTm and/or WTc is an integral >=1, it indicated a deterministically triggering strategy. In contrast, when 1>WT>0, it indicated a stochastically triggering strategy and the WT value itself is used as the acceptance probability. The parameter space between the waiting time for mortality (WTm-[0.1,40] and colonization (WTc-[0.1,40] was traversed to explore the coexistence and non-coexistence regions. The role of defense award was evaluated. My results showed that, one non-coexistence region is identified consistently, located at the area where 1>=WTm>=0.3 and 40>=WTc>=0.1. As a consequence, it was found that the coexistence of cooperators and defectors in the community is largely dependent on the waiting time of mortality events, regardless of the defense or cooperation rewards. When the mortality events happen in terms of stochastic waiting time (1>=WTm>=0.3, extinction of either cooperators or defectors or both could be very likely, leading to the emergence of non-coexistence scenarios. However, when the mortality events occur in forms of relatively long deterministic

  18. Forms of Manifestation regarding Tax Evasion: New Approaches

    Directory of Open Access Journals (Sweden)

    Alia Gabriela DUŢĂ

    2015-09-01

    Full Text Available Tax evasion has existed, exists and will exist as long as the state and the tax will continue to exist, but the forms and ways of achievement are perfectly in time. In terms of how can be committed, the ratio that exists between this phenomenon and the current legislation, tax evasion, there are two manifestations: the lawful tax avoidance (performed at the shelter law; unlawful tax evasion (fraudulent or fraud. In terms of space can be identified: tax evasion and tax avoidance at national and international level. In recent years circumvention actions are transferred, increasingly more inside from national tax systems across state borders, action driven by trends economic globalization, political and social.

  19. FORMS OF TAX EVASION IN ROMANIA. ANALYTICAL PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    PETRE BREZEANU

    2011-01-01

    Full Text Available This study brings to the fore an analysis of the phenomenon of tax evasion in Romania. The perspective is broad, with a descriptive substrate, originally founded by highlighting the dimensions that define this phenomenon; later, the perspective is materialized by the presentation of tax evasion schemes that often takes the form of real complex fiscal and also financial engineering. The purpose of this work consists in the awareness of practitioners, academics and the public of the tax evasion forms useful in order to identify precise modalities to combat it. Since the volume of funds subject to the phenomenon of tax evasion is greater, the negative effects of macroeconomic environment.

  20. Toward a systems- and control-oriented agent framework.

    Science.gov (United States)

    Fregene, Kingsley; Kennedy, Diane C; Wang, David W L

    2005-10-01

    This paper develops a systems- and control-oriented intelligent agent framework called the hybrid intelligent control agent (HICA), as well as its composition into specific kinds of multiagent systems. HICA is essentially developed around a hybrid control system core so that knowledge-based planning and coordination can be integrated with verified hybrid control primitives to achieve the coordinated control of multiple multimode dynamical systems. The scheme is applied to the control of teams of unmanned air and ground vehicles engaged in a pursuit-evasion war game. Results are demonstrated in simulation.

  1. Risk Factors for Internet Gaming Disorder: Psychological Factors and Internet Gaming Characteristics.

    Science.gov (United States)

    Rho, Mi Jung; Lee, Hyeseon; Lee, Taek-Ho; Cho, Hyun; Jung, Dong Jin; Kim, Dai-Jin; Choi, In Young

    2017-12-27

    Background : Understanding the risk factors associated with Internet gaming disorder (IGD) is important to predict and diagnose the condition. The purpose of this study is to identify risk factors that predict IGD based on psychological factors and Internet gaming characteristics; Methods : Online surveys were conducted between 26 November and 26 December 2014. There were 3568 Korean Internet game users among a total of 5003 respondents. We identified 481 IGD gamers and 3087 normal Internet gamers, based on Diagnostic and Statistical Manual for Mental Disorders (DSM-5) criteria. Logistic regression analysis was applied to identify significant risk factors for IGD; Results : The following eight risk factors were found to be significantly associated with IGD: functional and dysfunctional impulsivity (odds ratio: 1.138), belief self-control (1.034), anxiety (1.086), pursuit of desired appetitive goals (1.105), money spent on gaming (1.005), weekday game time (1.081), offline community meeting attendance (2.060), and game community membership (1.393; p < 0.05 for all eight risk factors); Conclusions : These risk factors allow for the prediction and diagnosis of IGD. In the future, these risk factors could also be used to inform clinical services for IGD diagnosis and treatment.

  2. THE POSSIBLY PREVENTION AND COMBATING TAX EVASION

    Directory of Open Access Journals (Sweden)

    Daniela P. POPA

    2014-11-01

    - A faulty legislation that allows them to circumvent the failure to pay taxes. Measures to combat tax evasion must act in the areas of legislative, administrative and educational. The legislative drafting tax legislation seeks appropriate, clear, concise, stable and consistent. It is also necessary to eliminate or withdrawal of exemptions, reductions and deductions that give rise to multiple interpretations. In terms of administrative measures aimed at creating a comprehensive and operational information system, ensuring adequate administrative structures and instruments effectively combating tax evasion and training specialists with morality and professionalism required of shapes and sizes evasion.

  3. Adversarial Feature Selection Against Evasion Attacks.

    Science.gov (United States)

    Zhang, Fei; Chan, Patrick P K; Biggio, Battista; Yeung, Daniel S; Roli, Fabio

    2016-03-01

    Pattern recognition and machine learning techniques have been increasingly adopted in adversarial settings such as spam, intrusion, and malware detection, although their security against well-crafted attacks that aim to evade detection by manipulating data at test time has not yet been thoroughly assessed. While previous work has been mainly focused on devising adversary-aware classification algorithms to counter evasion attempts, only few authors have considered the impact of using reduced feature sets on classifier security against the same attacks. An interesting, preliminary result is that classifier security to evasion may be even worsened by the application of feature selection. In this paper, we provide a more detailed investigation of this aspect, shedding some light on the security properties of feature selection against evasion attacks. Inspired by previous work on adversary-aware classifiers, we propose a novel adversary-aware feature selection model that can improve classifier security against evasion attacks, by incorporating specific assumptions on the adversary's data manipulation strategy. We focus on an efficient, wrapper-based implementation of our approach, and experimentally validate its soundness on different application examples, including spam and malware detection.

  4. Cytomegalovirus immune evasion of myeloid lineage cells.

    Science.gov (United States)

    Brinkmann, Melanie M; Dağ, Franziska; Hengel, Hartmut; Messerle, Martin; Kalinke, Ulrich; Čičin-Šain, Luka

    2015-06-01

    Cytomegalovirus (CMV) evades the immune system in many different ways, allowing the virus to grow and its progeny to spread in the face of an adverse environment. Mounting evidence about the antiviral role of myeloid immune cells has prompted the research of CMV immune evasion mechanisms targeting these cells. Several cells of the myeloid lineage, such as monocytes, dendritic cells and macrophages, play a role in viral control, but are also permissive for CMV and are naturally infected by it. Therefore, CMV evasion of myeloid cells involves mechanisms that qualitatively differ from the evasion of non-CMV-permissive immune cells of the lymphoid lineage. The evasion of myeloid cells includes effects in cis, where the virus modulates the immune signaling pathways within the infected myeloid cell, and those in trans, where the virus affects somatic cells targeted by cytokines released from myeloid cells. This review presents an overview of CMV strategies to modulate and evade the antiviral activity of myeloid cells in cis and in trans.

  5. Host-pathogen interactions between the human innate immune system and Candida albicans—understanding and modeling defense and evasion strategies

    Science.gov (United States)

    Dühring, Sybille; Germerodt, Sebastian; Skerka, Christine; Zipfel, Peter F.; Dandekar, Thomas; Schuster, Stefan

    2015-01-01

    The diploid, polymorphic yeast Candida albicans is one of the most important human pathogenic fungi. C. albicans can grow, proliferate and coexist as a commensal on or within the human host for a long time. However, alterations in the host environment can render C. albicans virulent. In this review, we describe the immunological cross-talk between C. albicans and the human innate immune system. We give an overview in form of pairs of human defense strategies including immunological mechanisms as well as general stressors such as nutrient limitation, pH, fever etc. and the corresponding fungal response and evasion mechanisms. Furthermore, Computational Systems Biology approaches to model and investigate these complex interactions are highlighted with a special focus on game-theoretical methods and agent-based models. An outlook on interesting questions to be tackled by Systems Biology regarding entangled defense and evasion mechanisms is given. PMID:26175718

  6. Profit Tax Evasion Under Oligopoly With Endogenous Market Structure

    OpenAIRE

    Goerke, Laszlo; Runkel, Marco

    2006-01-01

    This note investigates the impact of profit tax evasion on firms' output decisions in a Cournot oligopoly setting in which the market structure is determined endogenously. It is shown that tax evasion intensifies market entry and raises aggregate output, while production of each incumbent firm decreases. Therefore, tax evasion choices affect activity decisions and an evadable profit tax distorts the market outcome.

  7. Cue-dependent memory-based smooth-pursuit in normal human subjects: importance of extra-retinal mechanisms for initial pursuit.

    Science.gov (United States)

    Ito, Norie; Barnes, Graham R; Fukushima, Junko; Fukushima, Kikuro; Warabi, Tateo

    2013-08-01

    Using a cue-dependent memory-based smooth-pursuit task previously applied to monkeys, we examined the effects of visual motion-memory on smooth-pursuit eye movements in normal human subjects and compared the results with those of the trained monkeys. These results were also compared with those during simple ramp-pursuit that did not require visual motion-memory. During memory-based pursuit, all subjects exhibited virtually no errors in either pursuit-direction or go/no-go selection. Tracking eye movements of humans and monkeys were similar in the two tasks, but tracking eye movements were different between the two tasks; latencies of the pursuit and corrective saccades were prolonged, initial pursuit eye velocity and acceleration were lower, peak velocities were lower, and time to reach peak velocities lengthened during memory-based pursuit. These characteristics were similar to anticipatory pursuit initiated by extra-retinal components during the initial extinction task of Barnes and Collins (J Neurophysiol 100:1135-1146, 2008b). We suggest that the differences between the two tasks reflect differences between the contribution of extra-retinal and retinal components. This interpretation is supported by two further studies: (1) during popping out of the correct spot to enhance retinal image-motion inputs during memory-based pursuit, pursuit eye velocities approached those during simple ramp-pursuit, and (2) during initial blanking of spot motion during memory-based pursuit, pursuit components appeared in the correct direction. Our results showed the importance of extra-retinal mechanisms for initial pursuit during memory-based pursuit, which include priming effects and extra-retinal drive components. Comparison with monkey studies on neuronal responses and model analysis suggested possible pathways for the extra-retinal mechanisms.

  8. Cultural Norms, the Persistence of Tax Evasion, and Economic Growth

    OpenAIRE

    Dimitrios Varvarigos

    2015-01-01

    I study the effects of tax evasion on economic growth by focusing on the cultural aspects of tax compliance and their effect on the extensive margin of tax evasion. A cultural norm that determines the contemptibility of tax dodging practices links the past incidence of tax evasion with the tax payers’ current incentives to conceal sources of income. This dynamic complementarity may lead to multiple equilibria in the evolution of tax evasion. Due to the latter’s effect on capital accumulation,...

  9. [The Questionnaire of Experiences Associated with Video games (CERV): an instrument to detect the problematic use of video games in Spanish adolescents].

    Science.gov (United States)

    Chamarro, Andres; Carbonell, Xavier; Manresa, Josep Maria; Munoz-Miralles, Raquel; Ortega-Gonzalez, Raquel; Lopez-Morron, M Rosa; Batalla-Martinez, Carme; Toran-Monserrat, Pere

    2014-01-01

    The aim of this study is to validate the Video Game-Related Experiences Questionnaire (CERV in Spanish). The questionnaire consists of 17 items, developed from the CERI (Internet-Related Experiences Questionnaire - Beranuy and cols.), and assesses the problematic use of non-massive video games. It was validated for adolescents in Compulsory Secondary Education. To validate the questionnaire, a confirmatory factor analysis (CFA) and an internal consistency analysis were carried out. The factor structure shows two factors: (a) Psychological dependence and use for evasion; and (b) Negative consequences of using video games. Two cut-off points were established for people with no problems in their use of video games (NP), with potential problems in their use of video games (PP), and with serious problems in their use of video games (SP). Results show that there is higher prevalence among males and that problematic use decreases with age. The CERV seems to be a good instrument for the screening of adolescents with difficulties deriving from video game use. Further research should relate problematic video game use with difficulties in other life domains, such as the academic field.

  10. Mayer control problem with probabilistic uncertainty on initial positions

    Science.gov (United States)

    Marigonda, Antonio; Quincampoix, Marc

    2018-03-01

    In this paper we introduce and study an optimal control problem in the Mayer's form in the space of probability measures on Rn endowed with the Wasserstein distance. Our aim is to study optimality conditions when the knowledge of the initial state and velocity is subject to some uncertainty, which are modeled by a probability measure on Rd and by a vector-valued measure on Rd, respectively. We provide a characterization of the value function of such a problem as unique solution of an Hamilton-Jacobi-Bellman equation in the space of measures in a suitable viscosity sense. Some applications to a pursuit-evasion game with uncertainty in the state space is also discussed, proving the existence of a value for the game.

  11. Determination of mercury evasion in a contaminated headwater stream.

    Science.gov (United States)

    Maprani, Antu C; Al, Tom A; Macquarrie, Kerry T; Dalziel, John A; Shaw, Sean A; Yeats, Phillip A

    2005-03-15

    Evasion from first- and second-order streams in a watershed may be a significant factor in the atmospheric recycling of volatile pollutants such as mercury; however, methods developed for the determination of Hg evasion rates from larger water bodies are not expected to provide satisfactory results in highly turbulent and morphologically complex first- and second-order streams. A new method for determining the Hg evasion rates from these streams, involving laboratory gas-indexing experiments and field tracer tests, was developed in this study to estimate the evasion rate of Hg from Gossan Creek, a first-order stream in the Upsalquitch River watershed in northern New Brunswick, Canada. Gossan Creek receives Hg-contaminated groundwater discharge from a gold mine tailings pile. Laboratory gas-indexing experiments provided the ratio of gas-exchange coefficients for zero-valent Hg to propane (tracer gas) of 0.81+/-0.16, suggesting that the evasion mechanism in highly turbulent systems can be described by the surface renewal model with an additional component of enhanced gas evasion probably related to the formation of bubbles. Deliberate field tracer tests with propane and chloride tracers were found to be a reliable and practical method for the determination of gas-exchange coefficients for small streams. Estimation of Hg evasion from the first 1 km of Gossan Creek indicates that about 6.4 kg of Hg per year is entering the atmosphere, which is a significant fraction of the regional sources of Hg to the atmosphere.

  12. CF-Pursuit: A Pursuit Method with a Clothoid Fitting and a Fuzzy Controller for Autonomous Vehicles

    Directory of Open Access Journals (Sweden)

    Yunxiao Shan

    2015-09-01

    Full Text Available Simple and efficient geometric controllers, like Pure-Pursuit, have been widely used in various types of autonomous vehicles to solve tracking problems. In this paper, we have developed a new pursuit method, named CF-Pursuit, which has been based on Pure-Pursuit but with certain differences. In CF-Pursuit, in order to reduce fitting errors, we used a clothoid C1 curve to replace the circle employed in Pure-Pursuit. This improvement to the fitting method helps the Pursuit method to decrease tracking errors. As regards the selection of look-ahead distance, we employed a fuzzy system to directly consider the path's curvature. There are three input variables in this fuzzy system, 6mcurvature, 9mcurvature and 12mcurvature, calculated from the clothoid fit with the current position and the goal position on the defined path. A Sugeno fuzzy model was adapted to output a reasonable look-ahead distance using the experiences of human drivers as well as our own tests. Compared with some other geometric controllers, CF-Pursuit performs better in robustness, cross track errors and stability. The results from field tests have proven the CF-Pursuit is a practical and efficient geometric method for the path tracking problems of autonomous vehicles.

  13. TAX EVASION UNDER THE INFLUENCE OF FISCAL POLICY MEASURES

    Directory of Open Access Journals (Sweden)

    IONUŢ-GHEORGHE CĂRĂUŞ

    2016-08-01

    Full Text Available The collection efficiency of the budget revenues depends largely on the ability of the State, through tax authorities empowered, to apply firm measures to prevent and fight against fraud and tax evasion. However, the phenomenon of fraud and tax evasion is a complex process that extends quickly beyond national borders. That is why it is necessary to the existence of international cooperation against fraud and tax evasion as much as possible, in accordance with the principle of good governess in the field of taxation, thus eliminating negative fiscal measures. Therefore it requires a strict monitoring of collection activities arranged by fiscal legislation of each EU Member State, the automatic exchange of information to be made permanent through mutual information between countries regarding incomes or financial liquidity held by individuals resident in other EU countries, by creating an effective mechanism to fight against tax evasion regarding VAT, by sending alerts between EU Member States in case of suspicious economic activities. Also, it is necessary to correlate and intensify measures to prevent and fight against tax evasion, addressing various issues in a different manner, namely in terms of the taxpayers. Thus, it is necessary to identify factors that cause taxpayers to evade from payment of tax liabilities and declarations in conjunction with tax burden or with the existing tax easing measures. Only in this context we can understand and fight against the phenomenon of tax evasion in the business environment. In this context, the research carried out has had as its principal objective to analyze the phenomenon of tax evasion in Romania as well as the capacity of the State to recover tax arrears through the application of enforcement measures. Descriptive analysis revealed a dynamic of tax evasion , the highest levels recorded in VAT .

  14. Optimal guidance law in quantum mechanics

    International Nuclear Information System (INIS)

    Yang, Ciann-Dong; Cheng, Lieh-Lieh

    2013-01-01

    Following de Broglie’s idea of a pilot wave, this paper treats quantum mechanics as a problem of stochastic optimal guidance law design. The guidance scenario considered in the quantum world is that an electron is the flight vehicle to be guided and its accompanying pilot wave is the guidance law to be designed so as to guide the electron to a random target driven by the Wiener process, while minimizing a cost-to-go function. After solving the stochastic optimal guidance problem by differential dynamic programming, we point out that the optimal pilot wave guiding the particle’s motion is just the wavefunction Ψ(t,x), a solution to the Schrödinger equation; meanwhile, the closed-loop guidance system forms a complex state–space dynamics for Ψ(t,x), from which quantum operators emerge naturally. Quantum trajectories under the action of the optimal guidance law are solved and their statistical distribution is shown to coincide with the prediction of the probability density function Ψ ∗ Ψ. -- Highlights: •Treating quantum mechanics as a pursuit-evasion game. •Reveal an interesting analogy between guided flight motion and guided quantum motion. •Solve optimal quantum guidance problem by dynamic programming. •Gives a formal proof of de Broglie–Bohm’s idea of a pilot wave. •The optimal pilot wave is shown to be a wavefunction solved from Schrödinger equation

  15. Optimal guidance law in quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ciann-Dong, E-mail: cdyang@mail.ncku.edu.tw; Cheng, Lieh-Lieh, E-mail: leo8101@hotmail.com

    2013-11-15

    Following de Broglie’s idea of a pilot wave, this paper treats quantum mechanics as a problem of stochastic optimal guidance law design. The guidance scenario considered in the quantum world is that an electron is the flight vehicle to be guided and its accompanying pilot wave is the guidance law to be designed so as to guide the electron to a random target driven by the Wiener process, while minimizing a cost-to-go function. After solving the stochastic optimal guidance problem by differential dynamic programming, we point out that the optimal pilot wave guiding the particle’s motion is just the wavefunction Ψ(t,x), a solution to the Schrödinger equation; meanwhile, the closed-loop guidance system forms a complex state–space dynamics for Ψ(t,x), from which quantum operators emerge naturally. Quantum trajectories under the action of the optimal guidance law are solved and their statistical distribution is shown to coincide with the prediction of the probability density function Ψ{sup ∗}Ψ. -- Highlights: •Treating quantum mechanics as a pursuit-evasion game. •Reveal an interesting analogy between guided flight motion and guided quantum motion. •Solve optimal quantum guidance problem by dynamic programming. •Gives a formal proof of de Broglie–Bohm’s idea of a pilot wave. •The optimal pilot wave is shown to be a wavefunction solved from Schrödinger equation.

  16. Decentralized indirect methods for learning automata games.

    Science.gov (United States)

    Tilak, Omkar; Martin, Ryan; Mukhopadhyay, Snehasis

    2011-10-01

    We discuss the application of indirect learning methods in zero-sum and identical payoff learning automata games. We propose a novel decentralized version of the well-known pursuit learning algorithm. Such a decentralized algorithm has significant computational advantages over its centralized counterpart. The theoretical study of such a decentralized algorithm requires the analysis to be carried out in a nonstationary environment. We use a novel bootstrapping argument to prove the convergence of the algorithm. To our knowledge, this is the first time that such analysis has been carried out for zero-sum and identical payoff games. Extensive simulation studies are reported, which demonstrate the proposed algorithm's fast and accurate convergence in a variety of game scenarios. We also introduce the framework of partial communication in the context of identical payoff games of learning automata. In such games, the automata may not communicate with each other or may communicate selectively. This comprehensive framework has the capability to model both centralized and decentralized games discussed in this paper.

  17. Risk Factors for Internet Gaming Disorder: Psychological Factors and Internet Gaming Characteristics

    Directory of Open Access Journals (Sweden)

    Mi Jung Rho

    2017-12-01

    Full Text Available Background: Understanding the risk factors associated with Internet gaming disorder (IGD is important to predict and diagnose the condition. The purpose of this study is to identify risk factors that predict IGD based on psychological factors and Internet gaming characteristics; Methods: Online surveys were conducted between 26 November and 26 December 2014. There were 3568 Korean Internet game users among a total of 5003 respondents. We identified 481 IGD gamers and 3087 normal Internet gamers, based on Diagnostic and Statistical Manual for Mental Disorders (DSM-5 criteria. Logistic regression analysis was applied to identify significant risk factors for IGD; Results: The following eight risk factors were found to be significantly associated with IGD: functional and dysfunctional impulsivity (odds ratio: 1.138, belief self-control (1.034, anxiety (1.086, pursuit of desired appetitive goals (1.105, money spent on gaming (1.005, weekday game time (1.081, offline community meeting attendance (2.060, and game community membership (1.393; p < 0.05 for all eight risk factors; Conclusions: These risk factors allow for the prediction and diagnosis of IGD. In the future, these risk factors could also be used to inform clinical services for IGD diagnosis and treatment.

  18. Risk Factors for Internet Gaming Disorder: Psychological Factors and Internet Gaming Characteristics

    Science.gov (United States)

    Lee, Hyeseon; Lee, Taek-Ho; Cho, Hyun; Kim, Dai-Jin; Choi, In Young

    2017-01-01

    Background: Understanding the risk factors associated with Internet gaming disorder (IGD) is important to predict and diagnose the condition. The purpose of this study is to identify risk factors that predict IGD based on psychological factors and Internet gaming characteristics; Methods: Online surveys were conducted between 26 November and 26 December 2014. There were 3568 Korean Internet game users among a total of 5003 respondents. We identified 481 IGD gamers and 3087 normal Internet gamers, based on Diagnostic and Statistical Manual for Mental Disorders (DSM-5) criteria. Logistic regression analysis was applied to identify significant risk factors for IGD; Results: The following eight risk factors were found to be significantly associated with IGD: functional and dysfunctional impulsivity (odds ratio: 1.138), belief self-control (1.034), anxiety (1.086), pursuit of desired appetitive goals (1.105), money spent on gaming (1.005), weekday game time (1.081), offline community meeting attendance (2.060), and game community membership (1.393; p < 0.05 for all eight risk factors); Conclusions: These risk factors allow for the prediction and diagnosis of IGD. In the future, these risk factors could also be used to inform clinical services for IGD diagnosis and treatment. PMID:29280953

  19. A Monetary Policy Simulation Game

    Science.gov (United States)

    Lengwiler, Yvan

    2004-01-01

    The author presents a computer game that puts the player in the role of a central bank governor. The game is a stochastic simulation of a standard reduced form macro model, and the user interacts with this simulation by manipulating the interest rate. The problem the player faces is in many ways quite realistic--just as a real monetary authority,…

  20. Tax Evasion and the Shadow Economy

    OpenAIRE

    Oliver Reimers

    2015-01-01

    Leading scholars examine recent evidence from theoretical and empirical research on tax compliance and tax evasion, and provide an in-depth analysis of underlying methods. Strategies to fight tax evasion are evaluated and the motivations behind it are explored, as are the impact and size of the shadow economy in Europe. As well as promoting a better understanding of the issues, this book intends to stimulate further debate and, in so doing, broaden the exchange of ideas and concepts.

  1. Strategy Iteration Is Strongly Polynomial for 2-Player Turn-Based Stochastic Games with a Constant Discount Factor

    DEFF Research Database (Denmark)

    Hansen, Thomas Dueholm; Miltersen, Peter Bro; Zwick, Uri

    2013-01-01

    Ye [2011] showed recently that the simplex method with Dantzig’s pivoting rule, as well as Howard’s policy iteration algorithm, solve discounted Markov decision processes (MDPs), with a constant discount factor, in strongly polynomial time. More precisely, Ye showed that both algorithms terminate...... terminates after at most O(m1−γ log n1−γ) iterations. Second, and more importantly, we show that the same bound applies to the number of iterations performed by the strategy iteration (or strategy improvement) algorithm, a generalization of Howard’s policy iteration algorithm used for solving 2-player turn-based...... for 2-player turn-based stochastic games; it is strongly polynomial for a fixed discount factor, and exponential otherwise....

  2. The Temporal Derivative of Expected Utility: A Neural Mechanism for Dynamic Decision-making

    Science.gov (United States)

    Zhang, Xian; Hirsch, Joy

    2012-01-01

    Real world tasks involving moving targets, such as driving a vehicle, are performed based on continuous decisions thought to depend upon the temporal derivative of the expected utility (∂V/∂t), where the expected utility (V) is the effective value of a future reward. However, those neural mechanisms that underlie dynamic decision-making are not well understood. This study investigates human neural correlates of both V and ∂V/∂t using fMRI and a novel experimental paradigm based on a pursuit-evasion game optimized to isolate components of dynamic decision processes. Our behavioral data show that players of the pursuit-evasion game adopt an exponential discounting function, supporting the expected utility theory. The continuous functions of V and ∂V/∂t were derived from the behavioral data and applied as regressors in fMRI analysis, enabling temporal resolution that exceeded the sampling rate of image acquisition, hyper-temporal resolution, by taking advantage of numerous trials that provide rich and independent manipulation of those variables. V and ∂V/∂t were each associated with distinct neural activity. Specifically, ∂V/∂t was associated with anterior and posterior cingulate cortices, superior parietal lobule, and ventral pallidum, whereas V was primarily associated with supplementary motor, pre and post central gyri, cerebellum, and thalamus. The association between the ∂V/∂t and brain regions previously related to decision-making is consistent with the primary role of the temporal derivative of expected utility in dynamic decision-making. PMID:22963852

  3. The temporal derivative of expected utility: a neural mechanism for dynamic decision-making.

    Science.gov (United States)

    Zhang, Xian; Hirsch, Joy

    2013-01-15

    Real world tasks involving moving targets, such as driving a vehicle, are performed based on continuous decisions thought to depend upon the temporal derivative of the expected utility (∂V/∂t), where the expected utility (V) is the effective value of a future reward. However, the neural mechanisms that underlie dynamic decision-making are not well understood. This study investigates human neural correlates of both V and ∂V/∂t using fMRI and a novel experimental paradigm based on a pursuit-evasion game optimized to isolate components of dynamic decision processes. Our behavioral data show that players of the pursuit-evasion game adopt an exponential discounting function, supporting the expected utility theory. The continuous functions of V and ∂V/∂t were derived from the behavioral data and applied as regressors in fMRI analysis, enabling temporal resolution that exceeded the sampling rate of image acquisition, hyper-temporal resolution, by taking advantage of numerous trials that provide rich and independent manipulation of those variables. V and ∂V/∂t were each associated with distinct neural activity. Specifically, ∂V/∂t was associated with anterior and posterior cingulate cortices, superior parietal lobule, and ventral pallidum, whereas V was primarily associated with supplementary motor, pre and post central gyri, cerebellum, and thalamus. The association between the ∂V/∂t and brain regions previously related to decision-making is consistent with the primary role of the temporal derivative of expected utility in dynamic decision-making. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Optimization of stochastic discrete systems and control on complex networks computational networks

    CERN Document Server

    Lozovanu, Dmitrii

    2014-01-01

    This book presents the latest findings on stochastic dynamic programming models and on solving optimal control problems in networks. It includes the authors' new findings on determining the optimal solution of discrete optimal control problems in networks and on solving game variants of Markov decision problems in the context of computational networks. First, the book studies the finite state space of Markov processes and reviews the existing methods and algorithms for determining the main characteristics in Markov chains, before proposing new approaches based on dynamic programming and combinatorial methods. Chapter two is dedicated to infinite horizon stochastic discrete optimal control models and Markov decision problems with average and expected total discounted optimization criteria, while Chapter three develops a special game-theoretical approach to Markov decision processes and stochastic discrete optimal control problems. In closing, the book's final chapter is devoted to finite horizon stochastic con...

  5. Small Business Tax Evasion, is There a Case of Internal Finance?

    Directory of Open Access Journals (Sweden)

    Ilirjan Lipi

    2017-04-01

    Full Text Available As long as there are taxes, the incentive for evasion will exist as well. Studies for tax evasion are of interest in different fields like that of economics, public finance, personal finance, business administration, business finance, financial accounting, in the banking system etc. However, there are only a few studies about the internal causes and financial incentives that oblige decision-makers of small firms towards tax evasion. When we refer to business tax evasion, always brings to mind sensational cases of large businesses that evade taxes, but business tax evasion is a widespread phenomenon even to small firms. To be more competitive, small business must have a consistently entrepreneurial orientation, but limited financing prevents this, therefore the business savings from tax evasion is believed to be an internally funding path. The restrictions on small firms financing often make them orientate more toward internal generation of funds, which also has few alternatives. As a way to internal saving, firms often find tax evasion, which is not only a deviant and unethical behavior, but also puts firms into many difficulties in the long run. Consequently, the study aims to discuss the phenomenon of tax evasion in the managerial practice of small business in an Albanian region, as well as its financial cause as is perceived by the small business. The study findings report that the deviant behavior of businesses from taxes considers the need for internal financing as an important reason. The study concluded that savings from tax evasion is an alternative of internal financing primarily for small and early-staged firms, and that if entrepreneurs are capable of a good business model and competitive strategy, they will not need to make evasion.

  6. An optical model for implementing Parrondo’s game and designing stochastic game with long-term memory

    International Nuclear Information System (INIS)

    Si Tieyan

    2012-01-01

    Highlights: ► Using a photon propagating through a designed array of beam splitters to simulate Parrondo’s game paradox. ► Design the optical flowchart for implementing Parrondo history-dependent game paradox. ► Design new game with long-term memory on a designed tree lattice and loop lattice. - Abstract: An optical model for a photon propagating through a designed array of beam splitters is developed to give a physical implementation of Parrondo’s game and Parrondo’s history-dependent game. The winner in this optical model is a photon passed the beam splitter. The loser is a photon being reflected by the beam splitter. The optical beam splitter is the coin-tosser. We designed new games with long-term memory by using this optical diagram method. The optical output of the combined game of two losing games could be a win, or a loss, or an oscillation between win and loss. The modern technology to implement this optical model is well developed. A circularly polarized photon is a possible candidate for this physical implementation in laboratory.

  7. Path to Stochastic Stability: Comparative Analysis of Stochastic Learning Dynamics in Games

    KAUST Repository

    Jaleel, Hassan; Shamma, Jeff S.

    2018-01-01

    dynamics: Log-Linear Learning (LLL) and Metropolis Learning (ML). Although both of these dynamics have the same stochastically stable states, LLL and ML correspond to different behavioral models for decision making. Moreover, we demonstrate through

  8. Issues, Challenges and Problems with Tax Evasion: The Institutional Factors Approach

    Directory of Open Access Journals (Sweden)

    Mohd Rizal Palil

    2016-08-01

    Full Text Available Tax evasion, particularly in developing countries is a debatable issue. Evasion is a disease and needs to be minimized so that the black economy or hidden economy can be mitigated. This paper attempts to reveal the determinants of tax evasion from the institutional perspectives. The objective of this study is to identify the determinants of tax evasion a decade after the introduction of a Self-Assessment System (SAS. Three institutional perspectives of the determinants of tax evasion were examined, namely the probability of being detected, the role of the tax authority and the complexity of the tax system. The results suggested that the complexity of the system, and the probability of being detected had a significant impact on tax evasion. The results of this study could possibly contribute to the body of knowledge in lieu of combating tax evasion, as well as being an input to tax administrators and policymakers into which ways the determinants can affect compliance. The findings also provide an indicator for tax administrators of the relative importance of the tax system in assisting with the design of tax education programs, simplifying tax systems and developing a wider understanding of taxpayers’ behavior.

  9. Tax evasion between fraud and legality

    Directory of Open Access Journals (Sweden)

    Opreţ Laura-Anca

    2017-12-01

    Full Text Available This paper focuses on detailing the general coordinates regarding tax evasion and the necessity of creating a common unitary European legal framework. Accounting information might mirror erroneously in a certain measure the micro to macroeconomic tendency of fraud by showing a gross image of available resources. It is of the utmost importance to become fully aware of causes for illicit practices, ways to fight any fraud attempts and to evaluate the accounting mechanism that both creates and identifies tax evasion.

  10. The Tax Evasion in Ukraine: Causes and Methods of Countering

    Directory of Open Access Journals (Sweden)

    Parfentii Liudmyla A.

    2018-03-01

    Full Text Available The essence of the concept of tax evasion is researched; reasons of occurrence and development of this phenomenon are analyzed; proposals on the main directions of prevention and countering tax evasion have been developed. Analyzing, systematizing and generalizing the scientific works of many scholars, it was found that there is no unified approach to interpretation of the essence of this phenomenon in the context of legality and awareness of relevant actions in the scientific literature. As a result of the research the factors of tax evasion with the allocation of moral, political, economic, technical, and legal reasons have been systematized. The preconditions of tax evasion in Ukraine are analyzed, the most common schemes are indicated, resulting from which the budget of Ukraine suffers the greatest losses. Methods of countering tax offenses have been researched and necessity of development and implementation of measures on prevention and countering tax evasion at the State level has been substantiated. Prospects for further researches in this direction are studying of foreign experience of countering tax evasion and detailed analyzing of the tax minimization schemes prevalent in Ukraine with the purpose of identifying ways of elimination of possibility of their use.

  11. Monotone Approximations of Minimum and Maximum Functions and Multi-objective Problems

    International Nuclear Information System (INIS)

    Stipanović, Dušan M.; Tomlin, Claire J.; Leitmann, George

    2012-01-01

    In this paper the problem of accomplishing multiple objectives by a number of agents represented as dynamic systems is considered. Each agent is assumed to have a goal which is to accomplish one or more objectives where each objective is mathematically formulated using an appropriate objective function. Sufficient conditions for accomplishing objectives are derived using particular convergent approximations of minimum and maximum functions depending on the formulation of the goals and objectives. These approximations are differentiable functions and they monotonically converge to the corresponding minimum or maximum function. Finally, an illustrative pursuit-evasion game example with two evaders and two pursuers is provided.

  12. Monotone Approximations of Minimum and Maximum Functions and Multi-objective Problems

    Energy Technology Data Exchange (ETDEWEB)

    Stipanovic, Dusan M., E-mail: dusan@illinois.edu [University of Illinois at Urbana-Champaign, Coordinated Science Laboratory, Department of Industrial and Enterprise Systems Engineering (United States); Tomlin, Claire J., E-mail: tomlin@eecs.berkeley.edu [University of California at Berkeley, Department of Electrical Engineering and Computer Science (United States); Leitmann, George, E-mail: gleit@berkeley.edu [University of California at Berkeley, College of Engineering (United States)

    2012-12-15

    In this paper the problem of accomplishing multiple objectives by a number of agents represented as dynamic systems is considered. Each agent is assumed to have a goal which is to accomplish one or more objectives where each objective is mathematically formulated using an appropriate objective function. Sufficient conditions for accomplishing objectives are derived using particular convergent approximations of minimum and maximum functions depending on the formulation of the goals and objectives. These approximations are differentiable functions and they monotonically converge to the corresponding minimum or maximum function. Finally, an illustrative pursuit-evasion game example with two evaders and two pursuers is provided.

  13. Identifying Bacterial Immune Evasion Proteins Using Phage Display.

    Science.gov (United States)

    Fevre, Cindy; Scheepmaker, Lisette; Haas, Pieter-Jan

    2017-01-01

    Methods aimed at identification of immune evasion proteins are mainly rely on in silico prediction of sequence, structural homology to known evasion proteins or use a proteomics driven approach. Although proven successful these methods are limited by a low efficiency and or lack of functional identification. Here we describe a high-throughput genomic strategy to functionally identify bacterial immune evasion proteins using phage display technology. Genomic bacterial DNA is randomly fragmented and ligated into a phage display vector that is used to create a phage display library expressing bacterial secreted and membrane bound proteins. This library is used to select displayed bacterial secretome proteins that interact with host immune components.

  14. Rank dependent expected utility models of tax evasion.

    OpenAIRE

    Erling Eide

    2001-01-01

    In this paper the rank-dependent expected utility theory is substituted for the expected utility theory in models of tax evasion. It is demonstrated that the comparative statics results of the expected utility, portfolio choice model of tax evasion carry over to the more general rank dependent expected utility model.

  15. Continuous-Time Public Good Contribution Under Uncertainty: A Stochastic Control Approach

    International Nuclear Information System (INIS)

    Ferrari, Giorgio; Riedel, Frank; Steg, Jan-Henrik

    2017-01-01

    In this paper we study continuous-time stochastic control problems with both monotone and classical controls motivated by the so-called public good contribution problem. That is the problem of n economic agents aiming to maximize their expected utility allocating initial wealth over a given time period between private consumption and irreversible contributions to increase the level of some public good. We investigate the corresponding social planner problem and the case of strategic interaction between the agents, i.e. the public good contribution game. We show existence and uniqueness of the social planner’s optimal policy, we characterize it by necessary and sufficient stochastic Kuhn–Tucker conditions and we provide its expression in terms of the unique optional solution of a stochastic backward equation. Similar stochastic first order conditions prove to be very useful for studying any Nash equilibria of the public good contribution game. In the symmetric case they allow us to prove (qualitative) uniqueness of the Nash equilibrium, which we again construct as the unique optional solution of a stochastic backward equation. We finally also provide a detailed analysis of the so-called free rider effect.

  16. Continuous-Time Public Good Contribution Under Uncertainty: A Stochastic Control Approach

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Giorgio, E-mail: giorgio.ferrari@uni-bielefeld.de; Riedel, Frank, E-mail: frank.riedel@uni-bielefeld.de; Steg, Jan-Henrik, E-mail: jsteg@uni-bielefeld.de [Bielefeld University, Center for Mathematical Economics (Germany)

    2017-06-15

    In this paper we study continuous-time stochastic control problems with both monotone and classical controls motivated by the so-called public good contribution problem. That is the problem of n economic agents aiming to maximize their expected utility allocating initial wealth over a given time period between private consumption and irreversible contributions to increase the level of some public good. We investigate the corresponding social planner problem and the case of strategic interaction between the agents, i.e. the public good contribution game. We show existence and uniqueness of the social planner’s optimal policy, we characterize it by necessary and sufficient stochastic Kuhn–Tucker conditions and we provide its expression in terms of the unique optional solution of a stochastic backward equation. Similar stochastic first order conditions prove to be very useful for studying any Nash equilibria of the public good contribution game. In the symmetric case they allow us to prove (qualitative) uniqueness of the Nash equilibrium, which we again construct as the unique optional solution of a stochastic backward equation. We finally also provide a detailed analysis of the so-called free rider effect.

  17. Stochastic control theory dynamic programming principle

    CERN Document Server

    Nisio, Makiko

    2015-01-01

    This book offers a systematic introduction to the optimal stochastic control theory via the dynamic programming principle, which is a powerful tool to analyze control problems. First we consider completely observable control problems with finite horizons. Using a time discretization we construct a nonlinear semigroup related to the dynamic programming principle (DPP), whose generator provides the Hamilton–Jacobi–Bellman (HJB) equation, and we characterize the value function via the nonlinear semigroup, besides the viscosity solution theory. When we control not only the dynamics of a system but also the terminal time of its evolution, control-stopping problems arise. This problem is treated in the same frameworks, via the nonlinear semigroup. Its results are applicable to the American option price problem. Zero-sum two-player time-homogeneous stochastic differential games and viscosity solutions of the Isaacs equations arising from such games are studied via a nonlinear semigroup related to DPP (the min-ma...

  18. Probabilistic theory of mean field games with applications

    CERN Document Server

    Carmona, René

    2018-01-01

    This two-volume book offers a comprehensive treatment of the probabilistic approach to mean field game models and their applications. The book is self-contained in nature and includes original material and applications with explicit examples throughout, including numerical solutions. Volume I of the book is entirely devoted to the theory of mean field games without a common noise. The first half of the volume provides a self-contained introduction to mean field games, starting from concrete illustrations of games with a finite number of players, and ending with ready-for-use solvability results. Readers are provided with the tools necessary for the solution of forward-backward stochastic differential equations of the McKean-Vlasov type at the core of the probabilistic approach. The second half of this volume focuses on the main principles of analysis on the Wasserstein space. It includes Lions' approach to the Wasserstein differential calculus, and the applications of its results to the analysis of stochastic...

  19. Stability and Linear Quadratic Differential Games of Discrete-Time Markovian Jump Linear Systems with State-Dependent Noise

    Directory of Open Access Journals (Sweden)

    Huiying Sun

    2014-01-01

    Full Text Available We mainly consider the stability of discrete-time Markovian jump linear systems with state-dependent noise as well as its linear quadratic (LQ differential games. A necessary and sufficient condition involved with the connection between stochastic Tn-stability of Markovian jump linear systems with state-dependent noise and Lyapunov equation is proposed. And using the theory of stochastic Tn-stability, we give the optimal strategies and the optimal cost values for infinite horizon LQ stochastic differential games. It is demonstrated that the solutions of infinite horizon LQ stochastic differential games are concerned with four coupled generalized algebraic Riccati equations (GAREs. Finally, an iterative algorithm is presented to solve the four coupled GAREs and a simulation example is given to illustrate the effectiveness of it.

  20. Tax Rates and Tax Evasion: Evidence from "Missing Imports" in China.

    Science.gov (United States)

    Fisman, Raymond; Wei, Shang-Jin

    2004-01-01

    Tax evasion, by its very nature, is difficult to observe. We quantify the effects of tax rates on tax evasion by examining the relationship in China between the tariff schedule and the "evasion gap," which we define as the difference between Hong Kong's reported exports to China at the product level and China's reported imports from Hong…

  1. Fiscal Policy under Indeterminacy and Tax Evasion

    DEFF Research Database (Denmark)

    Busato, Francesco; Chiarini, Bruno; Marchetti, Enrico

    This paper shows under indeterminacy and tax evasion, an increase in corporate,labor or income tax rates pushes the economy into an expansionary pattern.These effects are reversed when the steady state is saddle-path stable.......This paper shows under indeterminacy and tax evasion, an increase in corporate,labor or income tax rates pushes the economy into an expansionary pattern.These effects are reversed when the steady state is saddle-path stable....

  2. Tax Evasion and Economic Growth in an Endogenous Growth Model

    OpenAIRE

    加藤, 秀弥; KATO, Hideya

    2004-01-01

    This paper presents an endogenous growth model with tax evasion where government expenditures affect production. An individual evades a tax so as to maximize his or her utility, the tax authority controls the detection probability to maximize net tax revenue, and the government chooses the income tax rate to maximize individuals’ utility. The main conclusions are as follows. First, the optical income tax rate with tax evasion is higher than that without tax evasion. Second, the rise in a ...

  3. International capital tax evasion and the foreign tax credit puzzle

    OpenAIRE

    Kimberley A. Scharf

    2001-01-01

    This paper examines the role of international tax evasion for the choice of an optimal foreign tax credit by a capital exporting region. Since a foreign tax credit raises the opportunity cost of concealing foreign source income, it can be employed to discourage evasion activity. The existence of international tax evasion possibilities could thus help rationalize a choice of tax credit in excess of a deduction-equivalent credit level. Our analysis shows that, in general the optimal credit will...

  4. CONTROVERSIAL ASPECTS REGARDING TAX EVASION

    Directory of Open Access Journals (Sweden)

    Mircea-Constantin SINESCU

    2018-05-01

    Full Text Available Throughout the paper, we have highlighted some controversial aspects regarding the crime of tax evasion, referring to some important decisions of the High Court of Cassation and Justice and also of the Bucharest Court of Appeal. Debating upon the impunity provision stated by art. 10 of Law no. 241/2005, the study also sheds light upon the issue of the perspective of the judicial organs regarding the juridical regime of the tax due for dividends. The main focus of the paper leads to the situations when there is legal ground for the tax due for dividends to be considered part of the damage caused by tax evasion crime. The study includes a short analysis of some relevant provisions of the Romanian Fiscal Code and also some aspects deriving from decisions issued by the Administrative and Tax Litigation Chamber of The High Court of Cassation and Justice concerning the legal regime of dividends. Consequently, the authors are presenting both perspectives of the interpretation of the issue regarding the tax due for dividends to be considered part of the damage caused by tax evasion crime, resulting from two decisions of the two Criminal Sections of The Bucharest Court of Appeal, also arguing in favour of the most solid interpretation among them

  5. Staphylococcal Immune Evasion Proteins: Structure, Function, and Host Adaptation.

    Science.gov (United States)

    Koymans, Kirsten J; Vrieling, Manouk; Gorham, Ronald D; van Strijp, Jos A G

    2017-01-01

    Staphylococcus aureus is a successful human and animal pathogen. Its pathogenicity is linked to its ability to secrete a large amount of virulence factors. These secreted proteins interfere with many critical components of the immune system, both innate and adaptive, and hamper proper immune functioning. In recent years, numerous studies have been conducted in order to understand the molecular mechanism underlying the interaction of evasion molecules with the host immune system. Structural studies have fundamentally contributed to our understanding of the mechanisms of action of the individual factors. Furthermore, such studies revealed one of the most striking characteristics of the secreted immune evasion molecules: their conserved structure. Despite high-sequence variability, most immune evasion molecules belong to a small number of structural categories. Another remarkable characteristic is that S. aureus carries most of these virulence factors on mobile genetic elements (MGE) or ex-MGE in its accessory genome. Coevolution of pathogen and host has resulted in immune evasion molecules with a highly host-specific function and prevalence. In this review, we explore how these shared structures and genomic locations relate to function and host specificity. This is discussed in the context of therapeutic options for these immune evasion molecules in infectious as well as in inflammatory diseases.

  6. The role of auditing in detecting tax evasion

    Directory of Open Access Journals (Sweden)

    Vržina Stefan

    2016-01-01

    Full Text Available Forthcoming paper opens questions about new area of audit operations and a new practical challenge for audit profession - detecting tax frauds. A growing problem of tax evasion, expressed as an act of illegal reduction of tax liabilities, points out to the inability of state authorities to reduce or neutralize tax evasion volume. Created as a consequence of previous fact, forthcoming paper has an objective to examine whether, and in which way, auditing financial statements could contribute to initial signalizing of tax evasion through expressing opinion about veracity and objectivity of accounting statements. Special focus is put on related-party transactions with entities registered in offshore zones. As they progress more and more, these transaction become materially significant, thus becoming a subject of audit examination.

  7. Role playing with synthetic cultures: the evasive rules of the game

    NARCIS (Netherlands)

    Hofstede, G.J.

    2005-01-01

    This article sums up ten years of experience with over 1400 participants of simulation games using synthetic cultures. Synthetic cultures are scripts for role players. They are derived from the five dimensions of culture in Hofstede¿s model. Playing the synthetic cultures leads to dynamics that

  8. Spike-based decision learning of Nash equilibria in two-player games.

    Directory of Open Access Journals (Sweden)

    Johannes Friedrich

    Full Text Available Humans and animals face decision tasks in an uncertain multi-agent environment where an agent's strategy may change in time due to the co-adaptation of others strategies. The neuronal substrate and the computational algorithms underlying such adaptive decision making, however, is largely unknown. We propose a population coding model of spiking neurons with a policy gradient procedure that successfully acquires optimal strategies for classical game-theoretical tasks. The suggested population reinforcement learning reproduces data from human behavioral experiments for the blackjack and the inspector game. It performs optimally according to a pure (deterministic and mixed (stochastic Nash equilibrium, respectively. In contrast, temporal-difference(TD-learning, covariance-learning, and basic reinforcement learning fail to perform optimally for the stochastic strategy. Spike-based population reinforcement learning, shown to follow the stochastic reward gradient, is therefore a viable candidate to explain automated decision learning of a Nash equilibrium in two-player games.

  9. Risk-sensitive mean-field games

    KAUST Repository

    Tembine, Hamidou

    2014-04-01

    In this paper, we study a class of risk-sensitive mean-field stochastic differential games. We show that under appropriate regularity conditions, the mean-field value of the stochastic differential game with exponentiated integral cost functional coincides with the value function satisfying a Hamilton -Jacobi- Bellman (HJB) equation with an additional quadratic term. We provide an explicit solution of the mean-field best response when the instantaneous cost functions are log-quadratic and the state dynamics are affine in the control. An equivalent mean-field risk-neutral problem is formulated and the corresponding mean-field equilibria are characterized in terms of backward-forward macroscopic McKean-Vlasov equations, Fokker-Planck-Kolmogorov equations, and HJB equations. We provide numerical examples on the mean field behavior to illustrate both linear and McKean-Vlasov dynamics. © 1963-2012 IEEE.

  10. Risk-sensitive mean-field games

    KAUST Repository

    Tembine, Hamidou; Zhu, Quanyan; Başar, Tamer

    2014-01-01

    In this paper, we study a class of risk-sensitive mean-field stochastic differential games. We show that under appropriate regularity conditions, the mean-field value of the stochastic differential game with exponentiated integral cost functional coincides with the value function satisfying a Hamilton -Jacobi- Bellman (HJB) equation with an additional quadratic term. We provide an explicit solution of the mean-field best response when the instantaneous cost functions are log-quadratic and the state dynamics are affine in the control. An equivalent mean-field risk-neutral problem is formulated and the corresponding mean-field equilibria are characterized in terms of backward-forward macroscopic McKean-Vlasov equations, Fokker-Planck-Kolmogorov equations, and HJB equations. We provide numerical examples on the mean field behavior to illustrate both linear and McKean-Vlasov dynamics. © 1963-2012 IEEE.

  11. Analysis of Driver Evasive Maneuvering Prior to Intersection Crashes Using Event Data Recorders.

    Science.gov (United States)

    Scanlon, John M; Kusano, Kristofer D; Gabler, Hampton C

    2015-01-01

    Intersection crashes account for over 4,500 fatalities in the United States each year. Intersection Advanced Driver Assistance Systems (I-ADAS) are emerging vehicle-based active safety systems that have the potential to help drivers safely navigate across intersections and prevent intersection crashes and injuries. The performance of an I-ADAS is expected to be highly dependent upon driver evasive maneuvering prior to an intersection crash. Little has been published, however, on the detailed evasive kinematics followed by drivers prior to real-world intersection crashes. The objective of this study was to characterize the frequency, timing, and kinematics of driver evasive maneuvers prior to intersection crashes. Event data recorders (EDRs) downloaded from vehicles involved in intersection crashes were investigated as part of NASS-CDS years 2001 to 2013. A total of 135 EDRs with precrash vehicle speed and braking application were downloaded to investigate evasive braking. A smaller subset of 59 EDRs that collected vehicle yaw rate was additionally analyzed to investigate evasive steering. Each vehicle was assigned to one of 3 precrash movement classifiers (traveling through the intersection, completely stopped, or rolling stop) based on the vehicle's calculated acceleration and observed velocity profile. To ensure that any significant steering input observed was an attempted evasive maneuver, the analysis excluded vehicles at intersections that were turning, driving on a curved road, or performing a lane change. Braking application at the last EDR-recorded time point was assumed to indicate evasive braking. A vehicle yaw rate greater than 4° per second was assumed to indicate an evasive steering maneuver. Drivers executed crash avoidance maneuvers in four-fifths of intersection crashes. A more detailed analysis of evasive braking frequency by precrash maneuver revealed that drivers performing complete or rolling stops (61.3%) braked less often than drivers

  12. Impaired smooth-pursuit in Parkinson's disease: normal cue-information memory, but dysfunction of extra-retinal mechanisms for pursuit preparation and execution.

    Science.gov (United States)

    Fukushima, Kikuro; Ito, Norie; Barnes, Graham R; Onishi, Sachiyo; Kobayashi, Nobuyoshi; Takei, Hidetoshi; Olley, Peter M; Chiba, Susumu; Inoue, Kiyoharu; Warabi, Tateo

    2015-03-01

    While retinal image motion is the primary input for smooth-pursuit, its efficiency depends on cognitive processes including prediction. Reports are conflicting on impaired prediction during pursuit in Parkinson's disease. By separating two major components of prediction (image motion direction memory and movement preparation) using a memory-based pursuit task, and by comparing tracking eye movements with those during a simple ramp-pursuit task that did not require visual memory, we examined smooth-pursuit in 25 patients with Parkinson's disease and compared the results with 14 age-matched controls. In the memory-based pursuit task, cue 1 indicated visual motion direction, whereas cue 2 instructed the subjects to prepare to pursue or not to pursue. Based on the cue-information memory, subjects were asked to pursue the correct spot from two oppositely moving spots or not to pursue. In 24/25 patients, the cue-information memory was normal, but movement preparation and execution were impaired. Specifically, unlike controls, most of the patients (18/24 = 75%) lacked initial pursuit during the memory task and started tracking the correct spot by saccades. Conversely, during simple ramp-pursuit, most patients (83%) exhibited initial pursuit. Popping-out of the correct spot motion during memory-based pursuit was ineffective for enhancing initial pursuit. The results were similar irrespective of levodopa/dopamine agonist medication. Our results indicate that the extra-retinal mechanisms of most patients are dysfunctional in initiating memory-based (not simple ramp) pursuit. A dysfunctional pursuit loop between frontal eye fields (FEF) and basal ganglia may contribute to the impairment of extra-retinal mechanisms, resulting in deficient pursuit commands from the FEF to brainstem. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  13. Object and subject of evasion of taxes and other compulsory payments

    Directory of Open Access Journals (Sweden)

    Koval L.

    2014-01-01

    Full Text Available The paper is devoted to such topical issue of Criminal Law as Object and Subject of Evasion of Taxes and Other Compulsory Payments. There are analyzed researched crime determination problems, which are connected with subject and object of tax and other compulsory payments evasion. In the course of the research, the author has made the conclusions that the object of the evasion of taxes and other compulsory payments group is the national economic interests. The direct object is the national economic interests in the sphere of state revenues or the national fiscal interests. While analyzing the law and regulations it is concluded that the subject of the evasion of taxes and other compulsory payments is the tax base (income, property, expenses and consumption, taxes, state and local government fees, as well as other payments determined by the State. The author has also concluded that the subject of the evasion of taxes and other compulsory payments does not include increase in the tax principal debt, fine and late charge, which are covered by the financial responsibility. The subject of the evasion of taxes and other compulsory payments may not include also income from illegal activity or proceeds resulting from criminal offences.

  14. A finite state, finite memory minimum principle, part 2. [a discussion of game theory, signaling, stochastic processes, and control theory

    Science.gov (United States)

    Sandell, N. R., Jr.; Athans, M.

    1975-01-01

    The development of the theory of the finite - state, finite - memory (FSFM) stochastic control problem is discussed. The sufficiency of the FSFM minimum principle (which is in general only a necessary condition) was investigated. By introducing the notion of a signaling strategy as defined in the literature on games, conditions under which the FSFM minimum principle is sufficient were determined. This result explicitly interconnects the information structure of the FSFM problem with its optimality conditions. The min-H algorithm for the FSFM problem was studied. It is demonstrated that a version of the algorithm always converges to a particular type of local minimum termed a person - by - person extremal.

  15. The economic approach to the problem of tax evasion and recommendations for Serbia

    Directory of Open Access Journals (Sweden)

    Milosavljević Valentina

    2016-01-01

    Full Text Available Tax evasion is a global problem and it has severe consequences for every country, regardless of differences in socio-economic and political structure. The basis for tax criminal offenses is embodied in different manifestations of tax evasion, especially when taking into account that tax evasion is also the most important form of informal economy. Since the taxation achieves not only fiscal, but also objectives in the field of economic and social policy, tax evasion has consequences on the economic and socio-political level. After introductory considerations, the paper shows the topicality of this issue, then the analysis of theoretical and practical features of tax evasion, as the basic fiscal criminal offense in the new Criminal Law of the Republic of Serbia, while the economic approach to the problem of tax evasion is based on an analysis of individual behavior of taxpayers.

  16. IMPACT OF TAX EVASION ON THE ECONOMIC GROWTH IN THE EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    FLORIN BOȘTINĂ

    2017-12-01

    Full Text Available The relevance of the research topic emerges from the fact that an important part of the fiscal revenues is lost annually through activities of fiscal planning, fiscal circumvention and tax evasion, undertaken by the private sector. In this respect, the aim of the paper is to estimate, by using the econometric analysis, the impact of tax evasion on the economic growth in the European Union for the period 1997-2010 for which the data was available. For the tax evasion it have been used index as a proxy that optimizes by maximum. Thus the main hypothesis (that the index tax evasion positively influences the economic growth was not rejected, even after including some specific control variables in the regressive models. In other words, as tax evasion is increased the economic growth is likely to decrease.

  17. A Probabilistic-Numerical Approximation for an Obstacle Problem Arising in Game Theory

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, Christine, E-mail: christine.gruen@univ-brest.fr [Laboratoire de Mathematiques de Brest UMR 6205 (France)

    2012-12-15

    We investigate a two-player zero-sum stochastic differential game in which one of the players has more information on the game than his opponent. We show how to construct numerical schemes for the value function of this game, which is given by the solution of a quasilinear partial differential equation with obstacle.

  18. A Probabilistic-Numerical Approximation for an Obstacle Problem Arising in Game Theory

    International Nuclear Information System (INIS)

    Grün, Christine

    2012-01-01

    We investigate a two-player zero-sum stochastic differential game in which one of the players has more information on the game than his opponent. We show how to construct numerical schemes for the value function of this game, which is given by the solution of a quasilinear partial differential equation with obstacle.

  19. International Tax Evasion in the Current Geopolitical Context

    OpenAIRE

    Constantin Sergiu-Bogdan

    2014-01-01

    Tax evasion means the avoidance of declaring and paying the tax obligations. Through the manifestation of this phenomenon, the state incomes are reduced, the governments not being capable of complying with their tasks. As the economic globalization progresses, tax evasion becomes international thanks to the tax havens which usually are small states that provide various tax facilities to those who want to carry out their activity through their agency, especially through offshore companies. It ...

  20. Smooth pursuit eye movements and schizophrenia: literature review.

    Science.gov (United States)

    Franco, J G; de Pablo, J; Gaviria, A M; Sepúlveda, E; Vilella, E

    2014-09-01

    To review the scientific literature about the relationship between impairment on smooth pursuit eye movements and schizophrenia. Narrative review that includes historical articles, reports about basic and clinical investigation, systematic reviews, and meta-analysis on the topic. Up to 80% of schizophrenic patients have impairment of smooth pursuit eye movements. Despite the diversity of test protocols, 65% of patients and controls are correctly classified by their overall performance during this pursuit. The smooth pursuit eye movements depend on the ability to anticipate the target's velocity and the visual feedback, as well as on learning and attention. The neuroanatomy implicated in smooth pursuit overlaps to some extent with certain frontal cortex zones associated with some clinical and neuropsychological characteristics of the schizophrenia, therefore some specific components of smooth pursuit anomalies could serve as biomarkers of the disease. Due to their sedative effect, antipsychotics have a deleterious effect on smooth pursuit eye movements, thus these movements cannot be used to evaluate the efficacy of the currently available treatments. Standardized evaluation of smooth pursuit eye movements on schizophrenia will allow to use specific aspects of that pursuit as biomarkers for the study of its genetics, psychopathology, or neuropsychology. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  1. Levy's zero-one law in game-theoretic probability

    OpenAIRE

    Shafer, Glenn; Vovk, Vladimir; Takemura, Akimichi

    2009-01-01

    We prove a game-theoretic version of Levy's zero-one law, and deduce several corollaries from it, including non-stochastic versions of Kolmogorov's zero-one law, the ergodicity of Bernoulli shifts, and a zero-one law for dependent trials. Our secondary goal is to explore the basic definitions of game-theoretic probability theory, with Levy's zero-one law serving a useful role.

  2. Equilibrium Implications of Fiscal Policy with Tax Evasion

    DEFF Research Database (Denmark)

    Busato, Francesco; Chiarini, Bruno; Rey, Guido M.

    This paper studies equilibrium effects of fiscal policy disturbances within a dynamic general equilibrium model where tax evasion and underground activities are explicitly incorporated. There are three mainresults. (i) The underground sector mitigates the distortionary impact of fiscal policies......, while lesseningthe drop (and the rise) of aggregate production after restrictive (expansionary) tax shocks. (ii) Taxevasion and underground economy can rationalize expansionary response to contractionary fiscal policies;(iii) A dynamic general equilibrium with tax evasion gives a rational justification...

  3. Fixation times in evolutionary games under weak selection

    International Nuclear Information System (INIS)

    Altrock, Philipp M; Traulsen, Arne

    2009-01-01

    In evolutionary game dynamics, reproductive success increases with the performance in an evolutionary game. If strategy A performs better than strategy B, strategy A will spread in the population. Under stochastic dynamics, a single mutant will sooner or later take over the entire population or go extinct. We analyze the mean exit times (or average fixation times) associated with this process. We show analytically that these times depend on the payoff matrix of the game in an amazingly simple way under weak selection, i.e. strong stochasticity: the payoff difference Δπ is a linear function of the number of A individuals i, Δπ=u i+v. The unconditional mean exit time depends only on the constant term v. Given that a single A mutant takes over the population, the corresponding conditional mean exit time depends only on the density dependent term u. We demonstrate this finding for two commonly applied microscopic evolutionary processes.

  4. Android Rooting: An Arms Race between Evasion and Detection

    Directory of Open Access Journals (Sweden)

    Long Nguyen-Vu

    2017-01-01

    Full Text Available We present an arms race between rooting detection and rooting evasion. We investigate different methods to detect rooted device at both Java and native level and evaluate the counterattack from major hooking tools. To this end, an extensive study of Android rooting has been conducted, which includes the techniques to root the device and make it invisible to the detection of mobile antimalware product. We then analyze the evasion loopholes and in turn enhance our rooting detection tool. We also apply evasion techniques on rooted device and compare our work with 92 popular root checking applications and 18 banking and finance applications. Results show that most of them do not suffice and can be evaded through API hooking or static file renaming. Furthermore, over 28000 Android applications have been analyzed and evaluated in order to diagnose the characteristics of rooting in recent years. Our study shows that rooting has become more and more prevalent as an inevitable trend, and it raises big security concerns regarding detection and evasion. As a proof of concept, we have published our rooting detection application to Google Play Store to demonstrate the work presented in this paper.

  5. Construction of solutions in certain differential games with phase constraints

    International Nuclear Information System (INIS)

    Grigor'eva, S V; Uspenskii, A A; Ushakov, V N; Pakhotinskikh, V Yu

    2005-01-01

    A differential approach-evasion game with fixed termination time is studied. It is assumed that the phase vector of the conflict-control system is subjected to constraints that form a closed set in the position space. The ideology of stable bridges is used for solving the problem. A method of convolution is proposed, which is used in several problems for constructing explicitly the stable absorption operator defining the stable bridges. A method of approximate construction of the maximal stable bridge in this game is suggested. The relations are written down that define a system of sets approximating the maximal stable bridge, and a control procedure with a guide is described, which can be used for obtaining an approximate solution of the approach problem.

  6. The consequences of different strategies for measuring tax evasion behavior

    Directory of Open Access Journals (Sweden)

    Ghavam Ahmadi

    2014-11-01

    Full Text Available This paper presents a study to investigate the effect of tax strategy on tax evasion in province of Zanjan, Iran. The study selects two randomly selected populations of 100 people from Tax organization and the people who file income tax with revenue agency. The study designs a questionnaire in Likert scale to study the effects of five variables namely; promote tax culture, lack of belief in tax payment consequences, filing false tax statement, tax exemption and general culture community as independent variables on tax evasion behavior. Using regression technique, the study has determined positive and meaningful relationships between tax evasion and independent variables.

  7. Evasion of Neutrophil Extracellular Traps by Respiratory Pathogens.

    Science.gov (United States)

    Storisteanu, Daniel M L; Pocock, Joanna M; Cowburn, Andrew S; Juss, Jatinder K; Nadesalingam, Angalee; Nizet, Victor; Chilvers, Edwin R

    2017-04-01

    The release of neutrophil extracellular traps (NETs) is a major immune mechanism intended to capture pathogens. These histone- and protease-coated DNA structures are released by neutrophils in response to a variety of stimuli, including respiratory pathogens, and have been identified in the airways of patients with respiratory infection, cystic fibrosis, acute lung injury, primary graft dysfunction, and chronic obstructive pulmonary disease. NET production has been demonstrated in the lungs of mice infected with Staphylococcus aureus, Klebsiella pneumoniae, and Aspergillus fumigatus. Since the discovery of NETs over a decade ago, evidence that "NET evasion" might act as an immune protection strategy among respiratory pathogens, including group A Streptococcus, Bordetella pertussis, and Haemophilus influenzae, has been growing, with the majority of these studies being published in the past 2 years. Evasion strategies fall into three main categories: inhibition of NET release by down-regulating host inflammatory responses; degradation of NETs using pathogen-derived DNases; and resistance to the microbicidal components of NETs, which involves a variety of mechanisms, including encapsulation. Hence, the evasion of NETs appears to be a widespread strategy to allow pathogen proliferation and dissemination, and is currently a topic of intense research interest. This article outlines the evidence supporting the three main strategies of NET evasion-inhibition, degradation, and resistance-with particular reference to common respiratory pathogens.

  8. Tänapäevased liikursuurtükid / Anna Kern

    Index Scriptorium Estoniae

    Kern, Anna

    2013-01-01

    Riigikaitse arengukavas (a. 2013-2022) on ette nähtud võimalused 1. jalaväebrigaadile hankida tänapäevased liikursuurtükid. Ülevaade liikursuurtükkide loomisest, kasutamisest sõdades ja tänapäevase liikursuurtüki iseloomustus. Näiteid erinevtest liikursuurtükkidest: Archer (Rootsi), Panzerhaubitze 2000 (Saksamaa), Caesar (Prantsusmaa), M777 (USA). Lisatud tabel tehniliste andmetega

  9. Vestibular-related frontal cortical areas and their roles in smooth-pursuit eye movements: representation of neck velocity, neck-vestibular interactions and memory-based smooth-pursuit

    Directory of Open Access Journals (Sweden)

    Kikuro eFukushima

    2011-12-01

    Full Text Available Smooth-pursuit eye movements are voluntary responses to small slow-moving objects in the fronto-parallel plane. They evolved in primates, who possess high-acuity foveae, to ensure clear vision about the moving target. The primate frontal cortex contains two smooth-pursuit related areas; the caudal part of the frontal eye fields (FEF and the supplementary eye fields (SEF. Both areas receive vestibular inputs. We review functional differences between the two areas in smooth-pursuit. Most FEF pursuit neurons signal pursuit parameters such as eye velocity and gaze-velocity, and are involved in cancelling the vestibulo-ocular reflex by linear addition of vestibular and smooth-pursuit responses. In contrast, gaze-velocity signals are rarely represented in the SEF. Most FEF pursuit neurons receive neck velocity inputs, while discharge modulation during pursuit and trunk-on-head rotation adds linearly. Linear addition also occurs between neck velocity responses and vestibular responses during head-on-trunk rotation in a task-dependent manner. During cross-axis pursuit-vestibular interactions, vestibular signals effectively initiate predictive pursuit eye movements. Most FEF pursuit neurons discharge during the interaction training after the onset of pursuit eye velocity, making their involvement unlikely in the initial stages of generating predictive pursuit. Comparison of representative signals in the two areas and the results of chemical inactivation during a memory-based smooth-pursuit task indicate they have different roles; the SEF plans smooth-pursuit including working memory of motion-direction, whereas the caudal FEF generates motor commands for pursuit eye movements. Patients with idiopathic Parkinson’s disease were asked to perform this task, since impaired smooth-pursuit and visual working memory deficit during cognitive tasks have been reported in most patients. Preliminary results suggested specific roles of the basal ganglia in memory

  10. Novel Evasion Mechanisms of the Classical Complement Pathway.

    Science.gov (United States)

    Garcia, Brandon L; Zwarthoff, Seline A; Rooijakkers, Suzan H M; Geisbrecht, Brian V

    2016-09-15

    Complement is a network of soluble and cell surface-associated proteins that gives rise to a self-amplifying, yet tightly regulated system with fundamental roles in immune surveillance and clearance. Complement becomes activated on the surface of nonself cells by one of three initiating mechanisms known as the classical, lectin, and alternative pathways. Evasion of complement function is a hallmark of invasive pathogens and hematophagous organisms. Although many complement-inhibition strategies hinge on hijacking activities of endogenous complement regulatory proteins, an increasing number of uniquely evolved evasion molecules have been discovered over the past decade. In this review, we focus on several recent investigations that revealed mechanistically distinct inhibitors of the classical pathway. Because the classical pathway is an important and specific mediator of various autoimmune and inflammatory disorders, in-depth knowledge of novel evasion mechanisms could direct future development of therapeutic anti-inflammatory molecules. Copyright © 2016 by The American Association of Immunologists, Inc.

  11. Large Lakes Dominate CO2 Evasion From Lakes in an Arctic Catchment

    Science.gov (United States)

    Rocher-Ros, Gerard; Giesler, Reiner; Lundin, Erik; Salimi, Shokoufeh; Jonsson, Anders; Karlsson, Jan

    2017-12-01

    CO2 evasion from freshwater lakes is an important component of the carbon cycle. However, the relative contribution from different lake sizes may vary, since several parameters underlying CO2 flux are size dependent. Here we estimated the annual lake CO2 evasion from a catchment in northern Sweden encompassing about 30,000 differently sized lakes. We show that areal CO2 fluxes decreased rapidly with lake size, but this was counteracted by the greater overall coverage of larger lakes. As a result, total efflux increased with lake size and the single largest lake in the catchment dominated the CO2 evasion (53% of all CO2 evaded). By contrast, the contribution from the smallest ponds (about 27,000) was minor (evasion at the landscape scale.

  12. Predictive Virtual Infection Modeling of Fungal Immune Evasion in Human Whole Blood

    Directory of Open Access Journals (Sweden)

    Maria T. E. Prauße

    2018-03-01

    Full Text Available Bloodstream infections by the human-pathogenic fungi Candida albicans and Candida glabrata increasingly occur in hospitalized patients and are associated with high mortality rates. The early immune response against these fungi in human blood comprises a concerted action of humoral and cellular components of the innate immune system. Upon entering the blood, the majority of fungal cells will be eliminated by innate immune cells, i.e., neutrophils and monocytes. However, recent studies identified a population of fungal cells that can evade the immune response and thereby may disseminate and cause organ dissemination, which is frequently observed during candidemia. In this study, we investigate the so far unresolved mechanism of fungal immune evasion in human whole blood by testing hypotheses with the help of mathematical modeling. We use a previously established state-based virtual infection model for whole-blood infection with C. albicans to quantify the immune response and identified the fungal immune-evasion mechanism. While this process was assumed to be spontaneous in the previous model, we now hypothesize that the immune-evasion process is mediated by host factors and incorporate such a mechanism in the model. In particular, we propose, based on previous studies that the fungal immune-evasion mechanism could possibly arise through modification of the fungal surface by as of yet unknown proteins that are assumed to be secreted by activated neutrophils. To validate or reject any of the immune-evasion mechanisms, we compared the simulation of both immune-evasion models for different infection scenarios, i.e., infection of whole blood with either C. albicans or C. glabrata under non-neutropenic and neutropenic conditions. We found that under non-neutropenic conditions, both immune-evasion models fit the experimental data from whole-blood infection with C. albicans and C. glabrata. However, differences between the immune-evasion models could be

  13. Predictive Virtual Infection Modeling of Fungal Immune Evasion in Human Whole Blood.

    Science.gov (United States)

    Prauße, Maria T E; Lehnert, Teresa; Timme, Sandra; Hünniger, Kerstin; Leonhardt, Ines; Kurzai, Oliver; Figge, Marc Thilo

    2018-01-01

    Bloodstream infections by the human-pathogenic fungi Candida albicans and Candida glabrata increasingly occur in hospitalized patients and are associated with high mortality rates. The early immune response against these fungi in human blood comprises a concerted action of humoral and cellular components of the innate immune system. Upon entering the blood, the majority of fungal cells will be eliminated by innate immune cells, i.e., neutrophils and monocytes. However, recent studies identified a population of fungal cells that can evade the immune response and thereby may disseminate and cause organ dissemination, which is frequently observed during candidemia. In this study, we investigate the so far unresolved mechanism of fungal immune evasion in human whole blood by testing hypotheses with the help of mathematical modeling. We use a previously established state-based virtual infection model for whole-blood infection with C. albicans to quantify the immune response and identified the fungal immune-evasion mechanism. While this process was assumed to be spontaneous in the previous model, we now hypothesize that the immune-evasion process is mediated by host factors and incorporate such a mechanism in the model. In particular, we propose, based on previous studies that the fungal immune-evasion mechanism could possibly arise through modification of the fungal surface by as of yet unknown proteins that are assumed to be secreted by activated neutrophils. To validate or reject any of the immune-evasion mechanisms, we compared the simulation of both immune-evasion models for different infection scenarios, i.e., infection of whole blood with either C. albicans or C. glabrata under non-neutropenic and neutropenic conditions. We found that under non-neutropenic conditions, both immune-evasion models fit the experimental data from whole-blood infection with C. albicans and C. glabrata . However, differences between the immune-evasion models could be observed for the

  14. Games of multicellularity.

    Science.gov (United States)

    Kaveh, Kamran; Veller, Carl; Nowak, Martin A

    2016-08-21

    Evolutionary game dynamics are often studied in the context of different population structures. Here we propose a new population structure that is inspired by simple multicellular life forms. In our model, cells reproduce but can stay together after reproduction. They reach complexes of a certain size, n, before producing single cells again. The cells within a complex derive payoff from an evolutionary game by interacting with each other. The reproductive rate of cells is proportional to their payoff. We consider all two-strategy games. We study deterministic evolutionary dynamics with mutations, and derive exact conditions for selection to favor one strategy over another. Our main result has the same symmetry as the well-known sigma condition, which has been proven for stochastic game dynamics and weak selection. For a maximum complex size of n=2 our result holds for any intensity of selection. For n≥3 it holds for weak selection. As specific examples we study the prisoner's dilemma and hawk-dove games. Our model advances theoretical work on multicellularity by allowing for frequency-dependent interactions within groups. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Complement evasion by Bordetella pertussis: implications for improving current vaccines.

    Science.gov (United States)

    Jongerius, Ilse; Schuijt, Tim J; Mooi, Frits R; Pinelli, Elena

    2015-04-01

    Bordetella pertussis causes whooping cough or pertussis, a highly contagious disease of the respiratory tract. Despite high vaccination coverage, reported cases of pertussis are rising worldwide and it has become clear that the current vaccines must be improved. In addition to the well-known protective role of antibodies and T cells during B. pertussis infection, innate immune responses such as the complement system play an essential role in B. pertussis killing. In order to evade this complement activation and colonize the human host, B. pertussis expresses several molecules that inhibit complement activation. Interestingly, one of the known complement evasion proteins, autotransporter Vag8, is highly expressed in the recently emerged B. pertussis isolates. Here, we describe the current knowledge on how B. pertussis evades complement-mediated killing. In addition, we compare this to complement evasion strategies used by other bacterial species. Finally, we discuss the consequences of complement evasion by B. pertussis on adaptive immunity and how identification of the bacterial molecules and the mechanisms involved in complement evasion might help improve pertussis vaccines.

  16. A evasão no ensino superior brasileiro Higher education institutions' evasion

    Directory of Open Access Journals (Sweden)

    Roberto Leal Lobo e Silva Filho

    2007-12-01

    Full Text Available Neste trabalho a evasão nas instituições de educação superior no Brasil é estudada com base em dados oficiais, em que se incluem análises regionais dos índices da evasão anual média e da evasão por tipo de instituição. Verifica-se uma correlação negativa entre os índices de evasão e a demanda por curso. Com vistas a possibilitar comparações, são apresentados dados internacionais que indicam que a evasão no Brasil não difere muito das médias internacionais.In this work, evasion in institutions of higher education is studied, based on official data, including regional analyses of annual mean evasion rates and evasion rates by type of institution. It was verified that there is a negative correlation between evasion rates an demand for undergraduate courses. Comparisons with international data are presented, pointing out that the evasion rates in Brazil do not differ a lot from those of other countries.

  17. Complex pattern of immune evasion in MSI colorectal cancer.

    Science.gov (United States)

    Ozcan, Mine; Janikovits, Jonas; von Knebel Doeberitz, Magnus; Kloor, Matthias

    2018-01-01

    Mismatch repair (MMR)-deficient cancers accumulate multiple insertion/deletion mutations at coding microsatellites (cMS), which give rise to frameshift peptide neoantigens. The high mutational neoantigen load of MMR-deficient cancers is reflected by pronounced anti-tumoral immune responses of the host and high responsiveness towards immune checkpoint blockade. However, immune evasion mechanisms can interfere with the immune response against MMR-deficient tumors. We here performed a comprehensive analysis of immune evasion in MMR-deficient colorectal cancers, focusing on HLA class I-mediated antigen presentation. 72% of MMR-deficient colorectal cancers of the DFCI database harbored alterations affecting genes involved in HLA class I-mediated antigen presentation, and 54% of these mutations were predicted to abrogate function. Mutations affecting the HLA class I transactivator NLRC5 were observed as a potential new immune evasion mechanism in 26% (6% abrogating) of the analyzed tumors. NLRC5 mutations in MMR-deficient cancers were associated with decreased levels of HLA class I antigen expression. In summary, the majority of MMR-deficient cancers display mutations interfering with HLA class I antigen presentation that reflect active immune surveillance and immunoselection during tumor development. Clinical studies focusing on immune checkpoint blockade in MSI cancer should account for the broad variety of immune evasion mechanisms as potential biomarkers of therapy success.

  18. Uncertainty quantification for mean field games in social interactions

    KAUST Repository

    Dia, Ben Mansour

    2016-01-09

    We present an overview of mean field games formulation. A comparative analysis of the optimality for a stochastic McKean-Vlasov process with time-dependent probability is presented. Then we examine mean-field games for social interactions and we show that optimizing the long-term well-being through effort and social feeling state distribution (mean-field) will help to stabilize couple (marriage). However , if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. Finally we introduce the Wiener chaos expansion for the construction of solution of stochastic differential equations of Mckean-Vlasov type. The method is based on the Cameron-Martin version of the Wiener Chaos expansion and allow to quantify the uncertainty in the optimality system.

  19. Uncertainty quantification for mean field games in social interactions

    KAUST Repository

    Dia, Ben Mansour

    2016-01-01

    We present an overview of mean field games formulation. A comparative analysis of the optimality for a stochastic McKean-Vlasov process with time-dependent probability is presented. Then we examine mean-field games for social interactions and we show that optimizing the long-term well-being through effort and social feeling state distribution (mean-field) will help to stabilize couple (marriage). However , if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. Finally we introduce the Wiener chaos expansion for the construction of solution of stochastic differential equations of Mckean-Vlasov type. The method is based on the Cameron-Martin version of the Wiener Chaos expansion and allow to quantify the uncertainty in the optimality system.

  20. Perceptual learning modifies untrained pursuit eye movements.

    Science.gov (United States)

    Szpiro, Sarit F A; Spering, Miriam; Carrasco, Marisa

    2014-07-07

    Perceptual learning improves detection and discrimination of relevant visual information in mature humans, revealing sensory plasticity. Whether visual perceptual learning affects motor responses is unknown. Here we implemented a protocol that enabled us to address this question. We tested a perceptual response (motion direction estimation, in which observers overestimate motion direction away from a reference) and a motor response (voluntary smooth pursuit eye movements). Perceptual training led to greater overestimation and, remarkably, it modified untrained smooth pursuit. In contrast, pursuit training did not affect overestimation in either pursuit or perception, even though observers in both training groups were exposed to the same stimuli for the same time period. A second experiment revealed that estimation training also improved discrimination, indicating that overestimation may optimize perceptual sensitivity. Hence, active perceptual training is necessary to alter perceptual responses, and an acquired change in perception suffices to modify pursuit, a motor response. © 2014 ARVO.

  1. Some Topics in Stochastic Control

    Science.gov (United States)

    2010-10-14

    assimilation problems. (a) Papers published in peer-reviewed journals (N/A for none) 1. R. Atar and A. Budhiraja. A stochastic differential game for...the inhomogeneous infinity-Laplace equation. Ann. Prob., 38 (2010), no. 2, 498--531. 2. R. Atar and A. Budhiraja. On near optimal trajectories for a...G. Aronsson. A mathematical model in sand mechanics: presentation and analysis. SIAM J. Appl. Math., 22 (1972), 437-458 [3] R. Atar and A. Budhiraja

  2. A review of game-theoretic models of road user behaviour.

    Science.gov (United States)

    Elvik, Rune

    2014-01-01

    This paper reviews game-theoretic models that have been developed to explain road user behaviour in situations where road users interact with each other. The paper includes the following game-theoretic models: 1.A general model of the interaction between road users and their possible reaction to measures improving safety (behavioural adaptation).2.Choice of vehicle size as a Prisoners’ dilemma game.3.Speed choice as a co-ordination game.4.Speed compliance as a game between drivers and the police.5.Merging into traffic from an acceleration lane as a mixed-strategy game.6.Choice of level of attention in following situations as an evolutionary game.7.Choice of departure time to avoid congestion as variant of a Prisoners’ dilemma game.8.Interaction between cyclists crossing the road and car drivers.9.Dipping headlights at night well ahead of the point when glare becomes noticeable.10.Choice of evasive action in a situation when cars are on collision course. The models reviewed are different in many respects, but a common feature of the models is that they can explain how informal norms of behaviour can develop among road users and be sustained even if these informal norms violate the formal regulations of the traffic code. Game-theoretic models are not applicable to every conceivable interaction between road users or to situations in which road users choose behaviour without interacting with other road users. Nevertheless, it is likely that game-theoretic models can be applied more widely than they have been until now. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. ALTERNATE PURSUIT WITH THREE PARTICIPANTS (THE CASE OF POINTWISE MEETING

    Directory of Open Access Journals (Sweden)

    Viktor Shiryayev

    2016-03-01

    Full Text Available The issues connected with alternate pursuit of escapees group are considered in a number of papers. So in papers [1–3] the solution of the problem has been found in the assumption that the next meeting is selected at the initial time (by the program and the players are moving straight. In paper [4] the solution of the task using the approach of R. Isaacs is given. In paper [5] the choice opportunities of the next meeting ( both software and positional are considered. The article deals with a simple differential game on the pursuer plane P and the coalition of two escapees E={E1,E2}.The movement of all the players are assumed as inertialess. The pursuer speed P exceeds the speed of each of the escapees. The targets, physical abilities and the exact location of each other in any moment of the game are known to all players. The price of the coalition (the pursuer P is (minus the total time spent by the pursuer P on the pointwise meeting with E1 and E2. A coincidence of pursuer and escapee location is meant under the meeting. The choice at the initial time of the persecution is supposed as given (software selectable regular meeting. The limit of the security zone of the second escapee has been found. A geometric approach is used in the problem solving. The resulting system of equations is solved numerically by means of computer algebra, in particular through the Wolfram Mathematics. After defining the boundary of the second escapee security zone one can study the game between the pursuer Р and three escapees acting in concord (the first escapee is eliminated from the game.

  4. Directional asymmetries in human smooth pursuit eye movements.

    Science.gov (United States)

    Ke, Sally R; Lam, Jessica; Pai, Dinesh K; Spering, Miriam

    2013-06-27

    Humans make smooth pursuit eye movements to bring the image of a moving object onto the fovea. Although pursuit accuracy is critical to prevent motion blur, the eye often falls behind the target. Previous studies suggest that pursuit accuracy differs between motion directions. Here, we systematically assess asymmetries in smooth pursuit. In experiment 1, binocular eye movements were recorded while observers (n = 20) tracked a small spot of light moving along one of four cardinal or diagonal axes across a featureless background. We analyzed pursuit latency, acceleration, peak velocity, gain, and catch-up saccade latency, number, and amplitude. In experiment 2 (n = 22), we examined the effects of spatial location and constrained stimulus motion within the upper or lower visual field. Pursuit was significantly faster (higher acceleration, peak velocity, and gain) and smoother (fewer and later catch-up saccades) in response to downward versus upward motion in both the upper and the lower visual fields. Pursuit was also more accurate and smoother in response to horizontal versus vertical motion. CONCLUSIONS. Our study is the first to report a consistent up-down asymmetry in human adults, regardless of visual field. Our findings suggest that pursuit asymmetries are adaptive responses to the requirements of the visual context: preferred motion directions (horizontal and downward) are more critical to our survival than nonpreferred ones.

  5. Cigarette tax avoidance and evasion: findings from the International Tobacco Control Policy Evaluation Project

    Science.gov (United States)

    Guindon, G. Emmanuel; Driezen, Pete; Chaloupka, Frank J.; Fong, Geoffrey T.

    2014-01-01

    Background Decades of research have produced overwhelming evidence that tobacco taxes reduce tobacco use and increase government tax revenue. The magnitude and effectiveness of taxes at reducing tobacco use provide an incentive for tobacco users, manufacturers and others, most notably criminal networks, to devise ways to avoid or evade tobacco taxes. Consequently, tobacco tax avoidance and tax evasion can reduce the public health and fiscal benefit of tobacco taxes. Objectives First, this study aims to document, using data from the International Tobacco Control Policy Evaluation Project (ITC), levels and trends in cigarette users’ tax avoidance and tax evasion behaviour in a sample of sixteen low-, middle- and high-income countries. Second, this study explores factors associated with cigarette tax avoidance and evasion. Methods We use data from ITC surveys conducted in 16 countries to estimate the extent and the type of cigarette tax avoidance/evasion between countries and across time. We use self-reported information about the source of a smoker’s last purchase of cigarettes or self-reported packaging information, or similar information gathered by the interviewers during face-to-face interviews to measure tax avoidance/evasion behaviours. We use generalized estimating equations (GEE) to explore individual-level factors that may affect the likelihood of cigarette tax avoidance or evasion in Canada, United States, United Kingdom and France. Findings We find prevalence estimates of cigarette tax avoidance/evasion vary substantially between countries and across time. In Canada, France and the United Kingdom, more than 10% of smokers report last purchasing cigarettes from low or untaxed sources while in Malaysia, some prevalence estimates suggest substantial cigarette tax avoidance/evasion. We also find important associations between household income and education and the likelihood to engage in tax avoidance/evasion. These associations, however, vary both in

  6. Tax Evasion in Romania: New Approaches

    Directory of Open Access Journals (Sweden)

    Sebastian George Perpelea

    2016-11-01

    Full Text Available Tax evasion has existed and will exist, and moreover, it will always be "creative and active" and will represent a current problem for any state. With the emergence of taxes also the phenomenon of "escape" from their path emerged, since the taxes determine the individuals to adopt an avoidance behavior or, at the best, to mitigate them. This phenomenon occurs in all the countries, obviously to varying degrees, starting from the level of individuals, to the level of large companies, it being favored by the legislative hiatuses, sometimes it being even encouraged by legislation, which legislation is drafted and voted by very the people. Thus, in our approach we will try to emphasize the actual causes of tax evasion and the consequences of this phenomenon on the society and the economy.

  7. A synthesis of rates and controls on elemental mercury evasion in the Great Lakes Basin

    International Nuclear Information System (INIS)

    Denkenberger, Joseph S.; Driscoll, Charles T.; Branfireun, Brian A.; Eckley, Chris S.; Cohen, Mark; Selvendiran, Pranesh

    2012-01-01

    Rates of surface-air elemental mercury (Hg 0 ) fluxes in the literature were synthesized for the Great Lakes Basin (GLB). For the majority of surfaces, fluxes were net positive (evasion). Digital land-cover data were combined with representative evasion rates and used to estimate annual Hg 0 evasion for the GLB (7.7 Mg/yr). This value is less than our estimate of total Hg deposition to the area (15.9 Mg/yr), suggesting the GLB is a net sink for atmospheric Hg. The greatest contributors to annual evasion for the basin are agricultural (∼55%) and forest (∼25%) land cover types, and the open water of the Great Lakes (∼15%). Areal evasion rates were similar across most land cover types (range: 7.0–21.0 μg/m 2 -yr), with higher rates associated with urban (12.6 μg/m 2 -yr) and agricultural (21.0 μg/m 2 -yr) lands. Uncertainty in these estimates could be partially remedied through a unified methodological approach to estimating Hg 0 fluxes. - Highlights: ► Considerable variability exists across spatial/temporal scales in Hg 0 evasion rates. ► Methodological approaches vary for estimating and reporting gaseous Hg 0 fluxes. ► Hg 0 evasion from the Great Lakes Basin is estimated at 7.7 Mg/yr (10.2 μg/m 2 -yr). ► Hg flux estimates suggest region is a net sink for atmospheric Hg. ► 95% of Hg 0 evasion in the region is from agriculture, forest, and the Great Lakes. - A synthesis of Hg evasion was conducted and this information was used to develop an estimate of Hg evasion for the Great Lakes Basin.

  8. Neurophysiology and Neuroanatomy of Smooth Pursuit in Humans

    Science.gov (United States)

    Lencer, Rebekka; Trillenberg, Peter

    2008-01-01

    Smooth pursuit eye movements enable us to focus our eyes on moving objects by utilizing well-established mechanisms of visual motion processing, sensorimotor transformation and cognition. Novel smooth pursuit tasks and quantitative measurement techniques can help unravel the different smooth pursuit components and complex neural systems involved…

  9. Seeing Themselves through Borrowed Eyes: Asian Americans in Ethnic Ambivalence/Evasion.

    Science.gov (United States)

    Tse, Lucy

    1998-01-01

    Focuses on the second stage of ethnic identity development, Ethnic Ambivalence/Evasion, experienced by Asian Americans through 39 personal narratives. Ethnic Ambivalence/Evasion, one of four identified stages that culminate with ethnic identity incorporation, typically occurs during the years of childhood and adolescence, and so is a stage…

  10. Contextual effects on smooth-pursuit eye movements.

    Science.gov (United States)

    Spering, Miriam; Gegenfurtner, Karl R

    2007-02-01

    Segregating a moving object from its visual context is particularly relevant for the control of smooth-pursuit eye movements. We examined the interaction between a moving object and a stationary or moving visual context to determine the role of the context motion signal in driving pursuit. Eye movements were recorded from human observers to a medium-contrast Gaussian dot that moved horizontally at constant velocity. A peripheral context consisted of two vertically oriented sinusoidal gratings, one above and one below the stimulus trajectory, that were either stationary or drifted into the same or opposite direction as that of the target at different velocities. We found that a stationary context impaired pursuit acceleration and velocity and prolonged pursuit latency. A drifting context enhanced pursuit performance, irrespective of its motion direction. This effect was modulated by context contrast and orientation. When a context was briefly perturbed to move faster or slower eye velocity changed accordingly, but only when the context was drifting along with the target. Perturbing a context into the direction orthogonal to target motion evoked a deviation of the eye opposite to the perturbation direction. We therefore provide evidence for the use of absolute and relative motion cues, or motion assimilation and motion contrast, for the control of smooth-pursuit eye movements.

  11. The game of cops and robbers on graphs

    CERN Document Server

    Bonato, Anthony

    2011-01-01

    This book is the first and only one of its kind on the topic of Cops and Robbers games, and more generally, on the field of vertex pursuit games on graphs. The book is written in a lively and highly readable fashion, which should appeal to both senior undergraduates and experts in the field (and everyone in between). One of the main goals of the book is to bring together the key results in the field; as such, it presents structural, probabilistic, and algorithmic results on Cops and Robbers games. Several recent and new results are discussed, along with a comprehensive set of references. The book is suitable for self-study or as a textbook, owing in part to the over 200 exercises. The reader will gain insight into all the main directions of research in the field and will be exposed to a number of open problems.

  12. Evolution of fairness and coalition formation in three-person ultimatum games.

    Science.gov (United States)

    Nishimura, Takeshi; Okada, Akira; Shirata, Yasuhiro

    2017-05-07

    We consider the evolution of fairness and coalition formation in a three-person ultimatum game in which the coalition value depends on its size. Traditional game theory, which assumes selfish and rational players, predicts the largest and efficient coalition with a proposer exploiting most of the total value. In a stochastic evolutionary model (the frequency-dependent Moran process with mutations) where players make errors in estimating the payoffs and strategies of others, evolutionary selection favors the formation of a two-person subcoalition under weak selection and in the low mutation limit if and only if its coalition value exceeds a high proportion (0.7) of that of the largest coalition. Proposers offer 30-35% of the subcoalition value to a coalition member, excluding a non-member. Multilateral bargaining is critically different from the bilateral one. Coalition-forming behavior may cause economic inefficiency and social exclusion. Stochastic evolutionary game theory thus provides theoretical support to explain the behavior of human subjects in economic experiments of a three-person ultimatum game. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Herpesvirus Evasion of Natural Killer Cells.

    Science.gov (United States)

    De Pelsmaeker, Steffi; Romero, Nicolas; Vitale, Massimo; Favoreel, Herman W

    2018-06-01

    Natural killer (NK) cells play an important role in the host response against viral infections and cancer development. They are able to kill virus-infected and tumor cells, and they produce different important cytokines that stimulate the antiviral and antitumor adaptive immune response, particularly interferon gamma. NK cells are of particular importance in herpesvirus infections, which is illustrated by systemic and life-threatening herpesvirus disease symptoms in patients with deficiencies in NK cell activity and by the myriad of reports describing herpesvirus NK cell evasion strategies. The latter is particularly obvious for cytomegaloviruses, but increasing evidence indicates that most, if not all, members of the herpesvirus family suppress NK cell activity to some extent. This review discusses the different NK cell evasion strategies described for herpesviruses and how this knowledge may translate to clinical applications. Copyright © 2018 American Society for Microbiology.

  14. Establishing the link between money laundering and tax evasion

    OpenAIRE

    Storm, Ansia

    2013-01-01

    No clear link has yet been made between tax evasion and money laundering although many (or all) of the professionals in this field may have already assumed the relation. The aim of the research that was conducted for the purposes of this article was to explore whether there is a clear link between tax evasion and money laundering. This was done by studying the relevant literature available on both subjects. The findings, that there is a clear link between these two offences, we...

  15. Doing smooth pursuit paradigms in Windows 7

    DEFF Research Database (Denmark)

    Wilms, Inge Linda

    predict strengths or deficits in perception and attention. However, smooth pursuit movements have been difficult to study and very little normative data is available for smooth pursuit performance in children and adults. This poster describes the challenges in setting up a smooth pursuit paradigm...... in Windows 7 with live capturing of eye movements using a Tobii TX300 eye tracker. In particular, the poster describes the challenges and limitations created by the hardware and the software...

  16. Corruption and Tax Evasion = Yolsuzluk ve Vergi Kaçakçılığı

    Directory of Open Access Journals (Sweden)

    Sacit Hadi AKDEDE

    2006-06-01

    Full Text Available Corruption and tax evasion problems have been investigated separately before. Tax evasion is also considered to be a corrupt behavior itself. However, in this paper, corruption is taken to be a bribe taken by a government official and tax evasion is defined as an illegal act to avoid paying taxes by violating tax laws. An interesting research question would be to see whether corruption can induce tax evasion in individuals ? It is found in the paper that the size of bribe can negatively affect tax evasion. It is shown that when a bribe is sufficiently large, taxpayers prefer to pay their taxes voluntarily, not to evade taxes.

  17. Cooperative Game for Fish Harvesting and Pollution Control

    KAUST Repository

    Dia, Ben Mansour

    2015-01-07

    We study fishery strategies in a shallow river subject to agricultural and industrial pollution. The flowing pollutants in the river are modeled by a nonlinear stochastic differential equation in a general manner. The logistic growth model for the fish population is modified to cover the pollution impact on the fish growth rate. A stochastic cooperative game is formulated to design strategies for preserving the fish population by controlling the pollution as well as the harvesting fish.

  18. Beating Cheaters at Their Own Game

    Science.gov (United States)

    Rauch, Joseph; Kondev, Jane; Sanchez, Alvaro

    2014-03-01

    Public goods games occur over many different scales in nature, from microbial biofilms to the human commons. On each scale stable populations of cooperators (members who invest into producing some good shared by the entire population) and cheaters (members who make no investment yet still share the common goods) has been observed. This observation raises interesting questions, like how do cooperators maintain their presence in a game that seems to heavily favor cheaters, and what strategies for cooperation could populations employ to increase their success? We propose a model of a public goods game with two different player populations, S and D, which employ two different strategies: the D population always cheats and the S population makes a stochastic decision whether to cooperate or not. We find that stochastic cooperation improves the success of the S population over the competing D population, but at a price. As the probability of cheating by the S players increases they outcompete the D players but the total population becomes more ecologically unstable (i.e., the likelihood of its extinction grows). We investigate this trade off between evolutionary success and ecological stability and propose experiments using populations of yeast cells to test our predictions.

  19. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway

    DEFF Research Database (Denmark)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine

    2017-01-01

    the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system....... Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part...... of the cascade. This review will cover the currently known lectin pathway evasion mechanisms and give examples of pathogens that operate these to increase their chance of invasion, survival and dissemination....

  20. The Effect of Tax Rates on Fiscal Evasion and Avoidance

    OpenAIRE

    Mentor Gashi; Halil Kukaj

    2016-01-01

    Abstract:In order to findelements that destimulate fiscal evasion or avoidance, we have submitted six elements, through the questionnaire, to determine which elements are that destimulate the fiscal evasion and avoidance, and evaluate their impact.This paper is focused in customs duty avoidance.The elements that we have submitted to evaluate their power, are: Powerful control during customs clearance, more efficient post clearance control, probability of subject investigation, higher fines, l...

  1. Asymmetric Information, Tax Evasion and Alternative Instruments of Government Revenue

    OpenAIRE

    Rangan Gupta

    2005-01-01

    Using a pure-exchange overlapping generations model, characterized with tax evasion and information asymmetry between the government (the social planner) and the financial intermediaries, we try and seek for the optimal tax and seigniorage plans, derived from the welfare maximizing objective of the social planner. We show that irrespective of whether the economy is characterized by tax evasion, or asymmetric information, a benevolent social planner, maximizing welfare and simultaneously finan...

  2. Efference copy failure during smooth pursuit eye movements in schizophrenia.

    Science.gov (United States)

    Spering, Miriam; Dias, Elisa C; Sanchez, Jamie L; Schütz, Alexander C; Javitt, Daniel C

    2013-07-17

    Abnormal smooth pursuit eye movements in patients with schizophrenia are often considered a consequence of impaired motion perception. Here we used a novel motion prediction task to assess the effects of abnormal pursuit on perception in human patients. Schizophrenia patients (n = 15) and healthy controls (n = 16) judged whether a briefly presented moving target ("ball") would hit/miss a stationary vertical line segment ("goal"). To relate prediction performance and pursuit directly, we manipulated eye movements: in half of the trials, observers smoothly tracked the ball; in the other half, they fixated on the goal. Strict quality criteria ensured that pursuit was initiated and that fixation was maintained. Controls were significantly better in trajectory prediction during pursuit than during fixation, their performance increased with presentation duration, and their pursuit gain and perceptual judgments were correlated. Such perceptual benefits during pursuit may be due to the use of extraretinal motion information estimated from an efference copy signal. With an overall lower performance in pursuit and perception, patients showed no such pursuit advantage and no correlation between pursuit gain and perception. Although patients' pursuit showed normal improvement with longer duration, their prediction performance failed to benefit from duration increases. This dissociation indicates relatively intact early visual motion processing, but a failure to use efference copy information. Impaired efference function in the sensory system may represent a general deficit in schizophrenia and thus contribute to symptoms and functional outcome impairments associated with the disorder.

  3. Pursuit and Evasion Strategies in Football.

    Science.gov (United States)

    O'Connell, James

    1995-01-01

    Explores strategies in the situation of a runner trying to evade a tackler on a football field. Enables the student to test intuitive strategies in a familiar situation using simple graphical and numerical methods or direct experimentation. (JRH)

  4. A VAR Analysis Regarding Tax Evasion and Tax Pressure in Romania

    Directory of Open Access Journals (Sweden)

    Boștină Florin

    2017-01-01

    The main aim of the paper is to identify the relationship that exists between tax evasion and tax pressure in Romania, between 2000 and 2013, using an autoregressive vector type of analysis. The VAR model with 3 lags can be considered as representative in order to describe autoregressive links between tax evasion and fiscal pressure in Romania.

  5. Cigarette tax avoidance and evasion: findings from the International Tobacco Control Policy Evaluation (ITC) Project.

    Science.gov (United States)

    Guindon, G Emmanuel; Driezen, Pete; Chaloupka, Frank J; Fong, Geoffrey T

    2014-03-01

    Decades of research have produced overwhelming evidence that tobacco taxes reduce tobacco use and increase government tax revenue. The magnitude and effectiveness of taxes in reducing tobacco use provide an incentive for tobacco users, manufacturers and others, most notably criminal networks, to devise ways to avoid or evade tobacco taxes. Consequently, tobacco tax avoidance and tax evasion can reduce the public health and fiscal benefit of tobacco taxes. First, this study aims to document, using data from the International Tobacco Control Policy Evaluation Project (ITC), levels and trends in cigarette users' tax avoidance and tax evasion behaviour in a sample of 16 low-, middle- and high-income countries. Second, this study explores factors associated with cigarette tax avoidance and evasion. We used data from ITC surveys conducted in 16 countries to estimate the extent and type of cigarette tax avoidance/evasion between countries and across time. We used self-reported information about the source of a smoker's last purchase of cigarettes or self-reported packaging information, or similar information gathered by the interviewers during face-to-face interviews to measure tax avoidance/evasion behaviours. We used generalised estimating equations to explore individual-level factors that may affect the likelihood of cigarette tax avoidance or evasion in Canada, the USA, the UK and France. We found prevalence estimates of cigarette tax avoidance/evasion vary substantially between countries and across time. In Canada, France and the UK, more than 10% of smokers reported last purchasing cigarettes from low or untaxed sources, while in Malaysia some prevalence estimates suggested substantial cigarette tax avoidance/evasion. We also found important associations between household income and education and the likelihood to engage in tax avoidance/evasion. These associations, however, varied both in direction and magnitude across countries.

  6. General Consideration on Legal Tax Evasion vs. Tax Fraud

    Directory of Open Access Journals (Sweden)

    Octavia-Daniela Steriopol

    2010-12-01

    Full Text Available The article is a brief overview of tax evasion as a complex social and economicphenomenon, of utmost importance, that today’s states confront with; its consequences seek to limitas much as possible, by legal and fiscal means, the eradication, which, at this point, is virtuallyimpossible. Tax evasion can be analysed from two points of view, the legal and the illegal aspect ofthe phenomenon or the fiscal fraud. The “fiscal paradises” had a very important role in the last years’activity.

  7. Symposium of the International Society of Dynamic Games

    CERN Document Server

    Haurie, Alain; Annals of the International Society of Dynamic Games

    1994-01-01

    Recent years have witnessed a surge of activity in the field of dynamic both theory and applications. Theoretical as well as practical games, in problems in zero-sum and nonzero-sum games, continuous time differential and discrete time multistage games, and deterministic and stochastic games games are currently being investigated by researchers in diverse disciplines, such as engineering, mathematics, biology, economics, management science, and political science. This surge of interest has led to the formation of the International Society of Dynamic Games (ISDG) in 1990, whose primary goal is to foster the development of advanced research and applications in the field of game theory. One important activity of the Society is to organize biannually an international symposium which aims at bringing together all those who contribute to the development of this active field of applied science. In 1992 the symposium was organized in Grimentz, Switzerland, under the supervision of an international scientific committe...

  8. A note on the neutrality of profit taxes with tax evasion and tax avoidance

    OpenAIRE

    Che-chiang Huang; Horn-in Kuo

    2014-01-01

    Traditional literature exploring the relationship between production and tax evasion ignores the impact of other activities on these two decisions. This paper incorporates firms' tax avoidance activities into the model of tax evasion. In contrast to conventional results, we find that profit tax is not necessarily neutral. In addition, the independency or separability of tax evasion and production decisions may not hold either whenever tax avoidance is present.

  9. Game-theoretic cooperativity in networks of self-interested units

    Science.gov (United States)

    Barto, Andrew G.

    1986-08-01

    The behavior of theoretical neural networks is often described in terms of competition and cooperation. I present an approach to network learning that is related to game and team problems in which competition and cooperation have more technical meanings. I briefly describe the application of stochastic learning automata to game and team problems and then present an adaptive element that is a synthesis of aspects of stochastic learning automata and typical neuron-like adaptive elements. These elements act as self-interested agents that work toward improving their performance with respect to their individual preference orderings. Networks of these elements can solve a variety of team decision problems, some of which take the form of layered networks in which the ``hidden units'' become appropriate functional components as they attempt to improve their own payoffs.

  10. Complex Immune Evasion Strategies in Classical Hodgkin Lymphoma.

    Science.gov (United States)

    Wein, Frederik; Weniger, Marc A; Höing, Benedikt; Arnolds, Judith; Hüttmann, Andreas; Hansmann, Martin-Leo; Hartmann, Sylvia; Küppers, Ralf

    2017-12-01

    The cellular microenvironment in classical Hodgkin lymphoma (cHL) is dominated by a mixed infiltrate of inflammatory cells with typically only about 1% Hodgkin and Reed/Sternberg (HRS) tumor cells. T cells are usually the largest population of cells in the cHL microenvironment, encompassing T helper (Th) cells, regulatory T cells (Tregs), and cytotoxic T cells. Th cells and Tregs presumably provide essential survival signals for HRS cells. Tregs are also involved in rescuing HRS cells from antitumor immune responses. An understanding of the immune evasion strategies of HRS cells is not only relevant for a characterization of the pathophysiology of cHL but is also clinically relevant, given the current treatment approaches targeting checkpoint inhibitors. Here, we characterized the cHL-specific CD4 + T-cell infiltrate regarding its role in immune evasion. Global gene expression analysis of CD4 + Th cells and Tregs isolated from cHL lymph nodes and reactive tonsils revealed that Treg signatures were enriched in CD4 + Th cells of cHL. Hence, HRS cells may induce Treg differentiation in Th cells, a conclusion supported by in vitro studies with Th cells and cHL cell lines. We also found evidence for immune-suppressive purinergic signaling and a role of the inhibitory receptor-ligand pairs B- and T-cell lymphocyte attenuator-herpesvirus entry mediator and CD200R-CD200 in promoting immune evasion. Taken together, this study highlights the relevance of Treg induction and reveals new immune checkpoint-driven immune evasion strategies in cHL. Cancer Immunol Res; 5(12); 1122-32. ©2017 AACR . ©2017 American Association for Cancer Research.

  11. Take-over performance in evasive manoeuvres

    NARCIS (Netherlands)

    Happee, R.; Gold, Christian; Radlmayr, Jonas; Hergeth, Sebastian; Bengler, Klaus

    2017-01-01

    We investigated after effects of automation in take-over scenarios in a high-end moving-base driving simulator. Drivers performed evasive manoeuvres encountering a blocked lane in highway driving. We compared the performance of drivers 1) during manual driving, 2) after automated driving with

  12. Nearly Cyclic Pursuit and its Hierarchical variant for Multi-agent Systems

    DEFF Research Database (Denmark)

    Iqbal, Muhammad; Leth, John-Josef; Ngo, Trung Dung

    2015-01-01

    The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version of the nea......The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version...

  13. THE LINK BETWEEN ACCOUNTING AND FISCAL EVASION

    Directory of Open Access Journals (Sweden)

    Silvia Lăzărescu (Marinescu

    2008-12-01

    Full Text Available In the literature, controversies have arisen concerning the link between accounting and fiscal evasion, which are the object of debates among specialists from different specialized organizations from many countries. Under the term of “creative accounting”, the American and European tax systems have made up an ensemble of accounting mechanisms and also of fiscal manipulation which increased the interest and involvement of the states in the mitigation of such fraud risks and fiscal subterfuges whose percentage in the countries’ GDP varies from 8 to 80%. Starting from the SWOT analysis of tax evasion in the real and underground economy, the specialists of the liberal trades are called to join the fight against fiscal fraud and share their professionalism in creating a real competitive environment characterized by fair play.

  14. Estimating Border Tax Evasion in Mozambique

    DEFF Research Database (Denmark)

    Arndt, Channing; Van Dunem, Joao Ernesto

    2009-01-01

    evasion. Results also strongly confirm the presence of fraudulent classification of merchandise into lower taxed product categories. Finally, analysis of the revenue implications of lower trade taxes finds that the revenue curve is quite flat but remains upward sloping with respect to the tax rate when...

  15. Distinguishing humans from computers in the game of go: A complex network approach

    Science.gov (United States)

    Coquidé, C.; Georgeot, B.; Giraud, O.

    2017-08-01

    We compare complex networks built from the game of go and obtained from databases of human-played games with those obtained from computer-played games. Our investigations show that statistical features of the human-based networks and the computer-based networks differ, and that these differences can be statistically significant on a relatively small number of games using specific estimators. We show that the deterministic or stochastic nature of the computer algorithm playing the game can also be distinguished from these quantities. This can be seen as a tool to implement a Turing-like test for go simulators.

  16. On search games that include ambush

    NARCIS (Netherlands)

    Alpern, S.; Fokkink, R.; Gal, S.; Timmer, M.

    2013-01-01

    We present a stochastic game that models ambush/search in a finite region Q which has area but no other structure. The searcher can search a unit area of Q in unit time or adopt an "ambush" mode for a certain period. The searcher "captures" the hider when the searched region contains the hider's

  17. Stochastic maintenance optimization at Candu power plants

    International Nuclear Information System (INIS)

    Doyle, E.K.; Duchesne, T.; Lee, C.G.; Cho, D.I.

    2004-01-01

    The use of various innovative maintenance optimization techniques at Bruce has lead to cost effective preventive maintenance applications for complex systems as previously reported at ICONE 6 in New Orleans (1996). Further refinement of the station maintenance strategy was evaluated via the applicability of statistical analysis of historical failure data. The viability of stochastic methods in Candu maintenance was illustrated at ICONE 10 in Washington DC (2002). The next phase consists of investigating the validity of using subjective elicitation techniques to obtain component lifetime distributions. This technique provides access to the elusive failure statistics, the lack of which is often referred to in the literature as the principal impediment preventing the use of stochastic methods in large industry. At the same time the technique allows very valuable information to be captured from the fast retiring 'baby boom generation'. Initial indications have been quite positive. The current reality of global competition necessitates the pursuit of all financial optimizers. The next construction phase in the power generation industry will soon begin on a worldwide basis. With the relatively high initial capital cost of new nuclear generation all possible avenues of financial optimization must be evaluated and implemented. (authors)

  18. Avoiding evasion: medical ethics education and emotion theory.

    Science.gov (United States)

    Leget, C

    2004-10-01

    Beginning with an exemplary case study, this paper diagnoses and analyses some important strategies of evasion and factors of hindrance that are met in the teaching of medical ethics to undergraduate medical students. Some of these inhibitions are inherent to ethical theories; others are connected with the nature of medicine or cultural trends. It is argued that in order to avoid an attitude of evasion in medical ethics teaching, a philosophical theory of emotions is needed that is able to clarify on a conceptual level the ethical importance of emotions. An approach is proposed with the help of the emotion theory Martha Nussbaum works out in her book Upheavals of thought. The paper ends with some practical recommendations.

  19. Tax Evasion and Swiss Bank Deposits

    DEFF Research Database (Denmark)

    Johannesen, Niels

    Bank deposits in jurisdictions with banking secrecy constitute an effective tool to evade taxes on interest income. A recent EU reform reduces the scope for this type of tax evasion by introducing a source tax on interest income earned by EU residents in Switzerland and several other jurisdictions...

  20. Immune Evasion by Epstein-Barr Virus.

    Science.gov (United States)

    Ressing, Maaike E; van Gent, Michiel; Gram, Anna M; Hooykaas, Marjolein J G; Piersma, Sytse J; Wiertz, Emmanuel J H J

    2015-01-01

    Epstein-Bar virus (EBV) is widespread within the human population with over 90% of adults being infected. In response to primary EBV infection, the host mounts an antiviral immune response comprising both innate and adaptive effector functions. Although the immune system can control EBV infection to a large extent, the virus is not cleared. Instead, EBV establishes a latent infection in B lymphocytes characterized by limited viral gene expression. For the production of new viral progeny, EBV reactivates from these latently infected cells. During the productive phase of infection, a repertoire of over 80 EBV gene products is expressed, presenting a vast number of viral antigens to the primed immune system. In particular the EBV-specific CD4+ and CD8+ memory T lymphocytes can respond within hours, potentially destroying the virus-producing cells before viral replication is completed and viral particles have been released. Preceding the adaptive immune response, potent innate immune mechanisms provide a first line of defense during primary and recurrent infections. In spite of this broad range of antiviral immune effector mechanisms, EBV persists for life and continues to replicate. Studies performed over the past decades have revealed a wide array of viral gene products interfering with both innate and adaptive immunity. These include EBV-encoded proteins as well as small noncoding RNAs with immune-evasive properties. The current review presents an overview of the evasion strategies that are employed by EBV to facilitate immune escape during latency and productive infection. These evasion mechanisms may also compromise the elimination of EBV-transformed cells, and thus contribute to malignancies associated with EBV infection.

  1. Strategic Leadership and Entrepreneurial Capability for Game Change

    DEFF Research Database (Denmark)

    Abdelgawad, Sondos G.; Zahra, Shaker A.; Velikova, Silviya Svejenova

    2013-01-01

    In this article, we introduce the concept of entrepreneurial capability (EC) to capture a firm’s capacity to sense, select, and shape opportunities, and synchronize their strategic moves and resources in pursuit of these opportunities. We define EC and explain its dimensions, highlighting its role...... in achieving and sustaining a firm’s competitive advantage. We also propose that EC is instrumental for realizing a firm’s game-changing strategies, that is, those strategic moves that fundamentally alter the nature, domain and dynamics of competition. Furthermore, we propose that strategic leadership plays...... an essential role in honing a company’s EC and aligning it with its game-changing strategy by creating an organizational context where transforming the business ecosystem becomes feasible. Finally, we articulate the implications of EC for managerial practices and for advancing future research...

  2. The Tax Compliance Demand Curve: A Diagrammatical Approach to Income Tax Evasion

    Science.gov (United States)

    Yaniv, Gideon

    2009-01-01

    One of the most interesting results in the tax evasion literature is that an increase in the income tax rate would increase tax compliance. Despite its peculiarity, this result has gained acceptance as a cornerstone for further developments of the rational tax evasion model. However, because of the mathematical format by which it is conveyed, this…

  3. Verification and Performance Evaluation of Timed Game Strategies

    DEFF Research Database (Denmark)

    David, Alexandre; Fang, Huixing; Larsen, Kim Guldstrand

    2014-01-01

    Control synthesis techniques, based on timed games, derive strategies to ensure a given control objective, e.g., time-bounded reachability. Model checking verifies correctness properties of systems. Statistical model checking can be used to analyse performance aspects of systems, e.g., energy...... consumption. In this work, we propose to combine these three techniques. In particular, given a strategy synthesized for a timed game and a given control objective, we want to make a deeper examination of the consequences of adopting this strategy. Firstly, we want to apply model checking to the timed game...... under the synthesized strategy in order to verify additional correctness properties. Secondly, we want to apply statistical model checking to evaluate various performance aspects of the synthesized strategy. For this, the underlying timed game is extended with relevant price and stochastic information...

  4. TAX EVASION IN CROSS BORDER TEXTILES OPERATIONS

    Directory of Open Access Journals (Sweden)

    ANDREESCU Nicoleta Alina

    2014-05-01

    Full Text Available We appreciated that the work can be divided into four chapters designed to enlighten, as far as possible the negative effects that evasion has, particularly the socio-economic phenomenon, faced by all countries. The negative effects generate an indisputable fraud phenomenon and tax evasion, which are felt directly on the level of tax revenue receipts, causing major distortions in the functioning of the mechanism of the market. Fiscal policy using the taxes generates psychological, financial, economic, social effects on a socio-economic environment. The public power that realizes the reality of the tax consequences of the action taken as solution changes of the tax system structure in order to modulate the effects according with the expected outcome. Therefore, the aimed pursued extent influences the technical characteristics of the taxes, and they influence the micro and macroeconomic effects. In this respect it has been proved that reducing tax evasion it allows the creation of budgetary resources necessary for allotting funds for economic growth. Developing and implementing a modern and predictable tax for a medium and long term, would be indispensable in the context of competition that occurs between the European states for attracting new investment and creating new jobs. The taxes do not have to shape the behavior of taxpayers, they must be the same regardless of the type of income, it should not include distortions. In order to be reasonable, the fiscal tax should be distributed as wide as possible.

  5. Smooth pursuit adaptation (SPA exhibits features useful to compensate changes in the properties of the smooth pursuit eye movement system due to usage.

    Directory of Open Access Journals (Sweden)

    Suryadeep eDash

    2013-10-01

    Full Text Available Smooth-pursuit adaptation (SPA refers to the fact that pursuit gain in the early, still open-loop response phase of the pursuit eye movement can be adjusted based on experience. For instance, if the target moves initially at a constant velocity for approximately 100-200ms and then steps to a higher velocity, subjects learn to up-regulate the pursuit gain associated with the initial target velocity (gain-increase SPA in order to reduce the retinal error resulting from the velocity step. Correspondingly, a step to a lower target velocity leads to a decrease in gain (gain-decrease SPA. In this study we demonstrate that the increase in peak eye velocity during gain-increase SPA is a consequence of expanding the duration of the eye acceleration profile while the decrease in peak velocity during gain-decrease SPA results from reduced peak eye acceleration but unaltered duration. Furthermore, we show that carrying out stereotypical smooth pursuit eye movements elicited by constant velocity target ramps for several hundred trials (= test of pursuit resilience leads to a clear drop in initial peak acceleration, a reflection of oculomotor and/ or cognitive fatigue. However, this drop in acceleration gets compensated by an increase in the duration of the acceleration profile, thereby keeping initial pursuit gain constant. The compensatory expansion of the acceleration profile in the pursuit resilience experiment is reminiscent of the one leading to gain-increase SPA, suggesting that both processes tap one and the same neuronal mechanism warranting a precise acceleration/ duration trade-off. Finally, we show that the ability to adjust acceleration duration during pursuit resilience depends on the integrity of the oculomotor vermis (OMV as indicated by the complete loss of the duration adjustment following a surgical lesion of the OMV in one rhesus monkey we could study.

  6. Linking tumor glycolysis and immune evasion in cancer: Emerging concepts and therapeutic opportunities.

    Science.gov (United States)

    Ganapathy-Kanniappan, Shanmugasundaram

    2017-08-01

    Metabolic reprogramming and immune evasion are two hallmarks of cancer. Metabolic reprogramming is exemplified by cancer's propensity to utilize glucose at an exponential rate which in turn is linked with "aerobic glycolysis", popularly known as the "Warburg effect". Tumor glycolysis is pivotal for the efficient management of cellular bioenergetics and uninterrupted cancer growth. Mounting evidence suggests that tumor glycolysis also plays a key role in instigating immunosuppressive networks that are critical for cancer cells to escape immune surveillance ("immune evasion"). Recent data show that induction of cellular stress or metabolic dysregulation sensitize cancer cells to antitumor immune cells implying that metabolic reprogramming and immune evasion harmonize during cancer progression. However, the molecular link between these two hallmarks of cancer remains obscure. In this review the molecular intricacies of tumor glycolysis that facilitate immune evasion has been discussed in the light of recent research to explore immunotherapeutic potential of targeting cancer metabolism. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. The Reform and Design of Commodity Taxes in the Presence of Tax Evasion with Illustrative Evidence from India

    OpenAIRE

    Ray, R.

    1994-01-01

    The literature on tax evasion and its implication for optimal tax theory has concentrated on income tax evasion. The issue of commodity tax evasion has received relatively little attention even though it is important in many cases, especially in developing countries. This paper proposes a theory of marginal reform of indirect taxes that recognises the presence of commodity tax evasion. Illustrative evidence from Indian data confirm the sensitivity of the Pareto improving direction of marginal...

  8. Effects of contrast on smooth pursuit eye movements.

    Science.gov (United States)

    Spering, Miriam; Kerzel, Dirk; Braun, Doris I; Hawken, Michael J; Gegenfurtner, Karl R

    2005-05-20

    It is well known that moving stimuli can appear to move more slowly when contrast is reduced (P. Thompson, 1982). Here we address the question whether changes in stimulus contrast also affect smooth pursuit eye movements. Subjects were asked to smoothly track a moving Gabor patch. Targets varied in velocity (1, 8, and 15 deg/s), spatial frequency (0.1, 1, 4, and 8 c/deg), and contrast, ranging from just below individual thresholds to maximum contrast. Results show that smooth pursuit eye velocity gain rose significantly with increasing contrast. Below a contrast level of two to three times threshold, pursuit gain, acceleration, latency, and positional accuracy were severely impaired. Therefore, the smooth pursuit motor response shows the same kind of slowing at low contrast that was demonstrated in previous studies on perception.

  9. THE HARMONISATION OF LEGISLATION ON COMBATTING TAX EVASION IN THE EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    DANIELA IANCU

    2011-04-01

    Full Text Available Combating tax evasion is part of the Lisbon Strategy. Tax fraud created a significant distortion in the functioning of the internal market and prevented fair competition.In its resolution of 2th of September 2008 on a coordinated strategy to improve the fight against fiscal fraud (2008/2033 (INI the European Parliament stressed that the Member States cannot combat cross-border fraud in isolation and called on the Commission to propose mechanisms to promote cooperation between Member States.This paper aims to analyse the main mechanisms to combat the tax evasion at the European level and, also, the changes that our country had to make in the field of legislation in order to achieve the EU standard on the fight against tax evasion.

  10. Stochastic Online Learning in Dynamic Networks under Unknown Models

    Science.gov (United States)

    2016-08-02

    The key is to develop online learning strategies at each individual node. Specifically, through local information exchange with its neighbors, each...infinitely repeated game with incomplete information and developed a dynamic pricing strategy referred to as Competitive and Cooperative Demand Learning...Stochastic Online Learning in Dynamic Networks under Unknown Models This research aims to develop fundamental theories and practical algorithms for

  11. Immune evasion mechanisms of human papillomavirus: An update.

    Science.gov (United States)

    Steinbach, Alina; Riemer, Angelika B

    2018-01-15

    Human papillomavirus (HPV) is the most frequently sexually transmitted agent in the world. It can cause cervical and other anogenital malignancies, and oropharyngeal cancer. HPV has the unique ability to persist in the host's epithelium for a long time-longer than most viruses do-which is necessary to complete its replication cycle. To this end, HPV has developed a variety of immune evasion mechanisms, which unfortunately also favor the progression of the disease from infection to chronic dysplasia and eventually to cancer. This article summarizes the current knowledge about HPV immune evasion strategies. A special emphasis lies in HPV-mediated changes of the antigen processing machinery, which is generating epitopes for T cells and contributes to the detectability of infected cells. © 2017 UICC.

  12. 34 CFR 668.207 - Preventing evasion of the consequences of cohort default rates.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Preventing evasion of the consequences of cohort default rates. 668.207 Section 668.207 Education Regulations of the Offices of the Department of Education... Cohort Default Rates § 668.207 Preventing evasion of the consequences of cohort default rates. (a...

  13. 34 CFR 668.188 - Preventing evasion of the consequences of cohort default rates.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Preventing evasion of the consequences of cohort default rates. 668.188 Section 668.188 Education Regulations of the Offices of the Department of Education... Two Year Cohort Default Rates § 668.188 Preventing evasion of the consequences of cohort default rates...

  14. A theory of Markovian time-inconsistent stochastic control in discrete time

    DEFF Research Database (Denmark)

    Bjork, Tomas; Murgoci, Agatha

    2014-01-01

    We develop a theory for a general class of discrete-time stochastic control problems that, in various ways, are time-inconsistent in the sense that they do not admit a Bellman optimality principle. We attack these problems by viewing them within a game theoretic framework, and we look for subgame...

  15. Effects of noise on convergent game-learning dynamics

    International Nuclear Information System (INIS)

    Sanders, James B T; Galla, Tobias; Shapiro, Jonathan L

    2012-01-01

    We study stochastic effects on the lagging anchor dynamics, a reinforcement learning algorithm used to learn successful strategies in iterated games, which is known to converge to Nash points in the absence of noise. The dynamics is stochastic when players only have limited information about their opponents’ strategic propensities. The effects of this noise are studied analytically in the case where it is small but finite, and we show that the statistics and correlation properties of fluctuations can be computed to a high accuracy. We find that the system can exhibit quasicycles, driven by intrinsic noise. If players are asymmetric and use different parameters for their learning, a net payoff advantage can be achieved due to these stochastic oscillations around the deterministic equilibrium. (paper)

  16. Play a Starring Role in Your Textbook: A Digital Web Platform with an Embedded Role-Playing Game

    Science.gov (United States)

    Spielvogel, Laura; Spielvogel, Christian

    2014-01-01

    In this report, we introduce our digital e-textbook web platform with an integrated role-playing game, which has been created for "introduction to anthropology" courses. We believe that textbooks have the potential to do more to motivate students' pursuit of learning if their material (topically organised chapters supported by…

  17. Tax avoidance, tax evasion, and tax flight: Do legal differences matter?

    OpenAIRE

    Schneider, Friedrich; Kirchler, Erich; Maciejovsky, Boris

    2001-01-01

    Although from an economic point of view, legal considerations apart, tax avoidance, tax evasion and tax flight have similar effects, namely a reduction of revenue yields, and are based on the same desire to reduce the tax burden, it is likely that individuals perceive them as different and as unequally fair. Overall, 252 fiscal officers, business students, business lawyers, and entrepreneurs produced spontaneous associations to a scenario either describing tax avoidance, tax evasion, or tax f...

  18. Attitudes towards Tax Evasion in Turkey and Australia: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Robert W. McGee

    2016-03-01

    Full Text Available The authors conducted a survey of 502 Turkish and Australian undergraduate and graduate business and economic students to determine their views regarding the ethics of tax evasion. These two groups were selected on the premise that their views represented the perceptions of two very different cultures, which has not been investigated in previous studies. The survey instrument required students to indicate their level of agreeableness to 18 general statements representing various scenarios in the socio-economic environment. The statements in the survey reflected the three main viewpoints regarding the ethics of tax evasion which have emerged from the literature to date. The results of the study show that although Turkish scores are significantly different from the Australian scores, both Turkish and Australian respondents believe that tax evasion can be ethically justifiable in certain situations, although some arguments are stronger than others.

  19. Environmental Noise Could Promote Stochastic Local Stability of Behavioral Diversity Evolution

    Science.gov (United States)

    Zheng, Xiu-Deng; Li, Cong; Lessard, Sabin; Tao, Yi

    2018-05-01

    In this Letter, we investigate stochastic stability in a two-phenotype evolutionary game model for an infinite, well-mixed population undergoing discrete, nonoverlapping generations. We assume that the fitness of a phenotype is an exponential function of its expected payoff following random pairwise interactions whose outcomes randomly fluctuate with time. We show that the stochastic local stability of a constant interior equilibrium can be promoted by the random environmental noise even if the system may display a complicated nonlinear dynamics. This result provides a new perspective for a better understanding of how environmental fluctuations may contribute to the evolution of behavioral diversity.

  20. Staphylococcus aureus innate immune evasion is lineage-specific: a bioinfomatics study.

    Science.gov (United States)

    McCarthy, Alex J; Lindsay, Jodi A

    2013-10-01

    Staphylococcus aureus is a major human pathogen, and is targeted by the host innate immune system. In response, S. aureus genomes encode dozens of secreted proteins that inhibit complement, chemotaxis and neutrophil activation resulting in successful evasion of innate immune responses. These proteins include immune evasion cluster proteins (IEC; Chp, Sak, Scn), staphylococcal superantigen-like proteins (SSLs), phenol soluble modulins (PSMs) and several leukocidins. Biochemical studies have indicated that genetic variants of these proteins can have unique functions. To ascertain the scale of genetic variation in secreted immune evasion proteins, whole genome sequences of 88 S. aureus isolates, representing 25 clonal complex (CC) lineages, in the public domain were analysed across 43 genes encoding 38 secreted innate immune evasion protein complexes. Twenty-three genes were variable, with between 2 and 15 variants, and the variants had lineage-specific distributions. They include genes encoding Eap, Ecb, Efb, Flipr/Flipr-like, Hla, Hld, Hlg, Sbi, Scin-B/C and 13 SSLs. Most of these protein complexes inhibit complement, chemotaxis and neutrophil activation suggesting that isolates from each S. aureus lineage respond to the innate immune system differently. In contrast, protein complexes that lyse neutrophils (LukSF-PVL, LukMF, LukED and PSMs) were highly conserved, but can be carried on mobile genetic elements (MGEs). MGEs also encode proteins with narrow host-specificities arguing that their acquisition has important roles in host/environmental adaptation. In conclusion, this data suggests that each lineage of S. aureus evades host immune responses differently, and that isolates can adapt to new host environments by acquiring MGEs and the immune evasion protein complexes that they encode. Cocktail therapeutics that targets multiple variant proteins may be the most appropriate strategy for controlling S. aureus infections. Copyright © 2013 Elsevier B.V. All rights

  1. 27 CFR 25.177 - Evasion of or failure to pay tax; failure to file a tax return.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Evasion of or failure to... Pay Tax § 25.177 Evasion of or failure to pay tax; failure to file a tax return. Sections 5671, 5673, 5684, 6651, and 6656 of Title 26 United States Code provide penalties for evasion or failure to pay tax...

  2. Predator evasion by white-tailed deer fawns

    Science.gov (United States)

    Grovenburg, Troy W.; Monteith, Kevin L.; Klaver, Robert W.; Jenks, Jonathan A.

    2012-01-01

    Despite their importance for understanding predator–prey interactions, factors that affect predator evasion behaviours of offspring of large ungulates are poorly understood. Our objective was to characterize the influence of selection and availability of escape cover and maternal presence on predator evasion by white-tailed deer, Odocoileus virginianus, fawns in the northern Great Plains, U.S.A. We observed 45 coyote, Canis latrans, chases of fawns, and we participated in 83 human chases of fawns during 2007–2009, of which, 19 and 42 chases, respectively, ended with capture of the fawn. Evasive techniques used by fawns were similar for human and coyote chases. Likelihood of a white-tailed deer fawn escaping capture, however, was influenced by deer group size and a number of antipredator behaviours, including aggressive defence by females, initial habitat and selection of escape cover, all of which were modified by the presence of parturient females. At the initiation of a chase, fawns in grasslands were more likely to escape, whereas fawns in forested cover, cultivated land or wheat were more likely to be captured by a coyote or human. Fawns fleeing to wetlands and grasslands also were less likely to be captured compared with those choosing forested cover, wheat and cultivated land. Increased probability of capture was associated with greater distance to wetland and grassland habitats and decreased distance to wheat. Use of wetland habitat as a successful antipredator strategy highlights the need for a greater understanding of the importance of habitat complexity in predator avoidance.

  3. The Reform and Design of Commodity Taxes in the Presence of Tax Evasion with Illustrative Evidence from India

    NARCIS (Netherlands)

    Ray, R.

    1994-01-01

    The literature on tax evasion and its implication for optimal tax theory has concentrated on income tax evasion. The issue of commodity tax evasion has received relatively little attention even though it is important in many cases, especially in developing countries. This paper proposes a theory of

  4. Plasticity in early immune evasion strategies of a bacterial pathogen.

    Science.gov (United States)

    Bernard, Quentin; Smith, Alexis A; Yang, Xiuli; Koci, Juraj; Foor, Shelby D; Cramer, Sarah D; Zhuang, Xuran; Dwyer, Jennifer E; Lin, Yi-Pin; Mongodin, Emmanuel F; Marques, Adriana; Leong, John M; Anguita, Juan; Pal, Utpal

    2018-04-17

    Borrelia burgdorferi is one of the few extracellular pathogens capable of establishing persistent infection in mammals. The mechanisms that sustain long-term survival of this bacterium are largely unknown. Here we report a unique innate immune evasion strategy of B. burgdorferi , orchestrated by a surface protein annotated as BBA57, through its modulation of multiple spirochete virulent determinants. BBA57 function is critical for early infection but largely redundant for later stages of spirochetal persistence, either in mammals or in ticks. The protein influences host IFN responses as well as suppresses multiple host microbicidal activities involving serum complement, neutrophils, and antimicrobial peptides. We also discovered a remarkable plasticity in BBA57-mediated spirochete immune evasion strategy because its loss, although resulting in near clearance of pathogens at the inoculum site, triggers nonheritable adaptive changes that exclude detectable nucleotide alterations in the genome but incorporate transcriptional reprograming events. Understanding the malleability in spirochetal immune evasion mechanisms that ensures their host persistence is critical for the development of novel therapeutic and preventive approaches to combat long-term infections like Lyme borreliosis.

  5. Tax evasion and growth: a banking approach

    Czech Academy of Sciences Publication Activity Database

    Gillman, M.; Kejak, Michal

    -, 2008/6 (2008), s. 1-32. ISBN 978-963-9796-21-8. ISSN 1785-377X Institutional research plan: CEZ:AV0Z70850503 Keywords : tax evasion * financial intermediation * endogenous growth Subject RIV: AH - Economics http://econ.core.hu/file/download/mtdp/MTDP0806.pdf

  6. Discrimination of curvature from motion during smooth pursuit eye movements and fixation.

    Science.gov (United States)

    Ross, Nicholas M; Goettker, Alexander; Schütz, Alexander C; Braun, Doris I; Gegenfurtner, Karl R

    2017-09-01

    Smooth pursuit and motion perception have mainly been investigated with stimuli moving along linear trajectories. Here we studied the quality of pursuit movements to curved motion trajectories in human observers and examined whether the pursuit responses would be sensitive enough to discriminate various degrees of curvature. In a two-interval forced-choice task subjects pursued a Gaussian blob moving along a curved trajectory and then indicated in which interval the curve was flatter. We also measured discrimination thresholds for the same curvatures during fixation. Motion curvature had some specific effects on smooth pursuit properties: trajectories with larger amounts of curvature elicited lower open-loop acceleration, lower pursuit gain, and larger catch-up saccades compared with less curved trajectories. Initially, target motion curvatures were underestimated; however, ∼300 ms after pursuit onset pursuit responses closely matched the actual curved trajectory. We calculated perceptual thresholds for curvature discrimination, which were on the order of 1.5 degrees of visual angle (°) for a 7.9° curvature standard. Oculometric sensitivity to curvature discrimination based on the whole pursuit trajectory was quite similar to perceptual performance. Oculometric thresholds based on smaller time windows were higher. Thus smooth pursuit can quite accurately follow moving targets with curved trajectories, but temporal integration over longer periods is necessary to reach perceptual thresholds for curvature discrimination. NEW & NOTEWORTHY Even though motion trajectories in the real world are frequently curved, most studies of smooth pursuit and motion perception have investigated linear motion. We show that pursuit initially underestimates the curvature of target motion and is able to reproduce the target curvature ∼300 ms after pursuit onset. Temporal integration of target motion over longer periods is necessary for pursuit to reach the level of precision found

  7. Stochastic volatility and stochastic leverage

    DEFF Research Database (Denmark)

    Veraart, Almut; Veraart, Luitgard A. M.

    This paper proposes the new concept of stochastic leverage in stochastic volatility models. Stochastic leverage refers to a stochastic process which replaces the classical constant correlation parameter between the asset return and the stochastic volatility process. We provide a systematic...... treatment of stochastic leverage and propose to model the stochastic leverage effect explicitly, e.g. by means of a linear transformation of a Jacobi process. Such models are both analytically tractable and allow for a direct economic interpretation. In particular, we propose two new stochastic volatility...... models which allow for a stochastic leverage effect: the generalised Heston model and the generalised Barndorff-Nielsen & Shephard model. We investigate the impact of a stochastic leverage effect in the risk neutral world by focusing on implied volatilities generated by option prices derived from our new...

  8. Viral evasion of DNA-stimulated innate immune responses.

    Science.gov (United States)

    Christensen, Maria H; Paludan, Søren R

    2017-01-01

    Cellular sensing of virus-derived nucleic acids is essential for early defenses against virus infections. In recent years, the discovery of DNA sensing proteins, including cyclic GMP-AMP synthase (cGAS) and gamma-interferon-inducible protein (IFI16), has led to understanding of how cells evoke strong innate immune responses against incoming pathogens carrying DNA genomes. The signaling stimulated by DNA sensors depends on the adaptor protein STING (stimulator of interferon genes), to enable expression of antiviral proteins, including type I interferon. To facilitate efficient infections, viruses have evolved a wide range of evasion strategies, targeting host DNA sensors, adaptor proteins and transcription factors. In this review, the current literature on virus-induced activation of the STING pathway is presented and we discuss recently identified viral evasion mechanisms targeting different steps in this antiviral pathway.

  9. Evasion of Cell Senescence Leads to Medulloblastoma Progression

    Directory of Open Access Journals (Sweden)

    Lukas Tamayo-Orrego

    2016-03-01

    Full Text Available How brain tumors progress from precancerous lesions to advanced cancers is not well understood. Using Ptch1+/− mice to study medulloblastoma progression, we found that Ptch1 loss of heterozygosity (LOH is an early event that is associated with high levels of cell senescence in preneoplasia. In contrast, advanced tumors have evaded senescence. Remarkably, we discovered that the majority of advanced medulloblastomas display either spontaneous, somatic p53 mutations or Cdkn2a locus inactivation. Consistent with senescence evasion, these p53 mutations are always subsequent to Ptch1 LOH. Introduction of a p53 mutation prevents senescence, accelerates tumor formation, and increases medulloblastoma incidence. Altogether, our results show that evasion of senescence associated with Ptch1 LOH allows progression to advanced tumors.

  10. Tax design-tax evasion relationship in Serbia: New empirical approach to standard theoretical model

    Directory of Open Access Journals (Sweden)

    Ranđelović Saša

    2015-01-01

    Full Text Available This paper provides evidence on the impact of the change in income tax rates and the degree of its progressivity on the scale of labour taxes evasion in Serbia, using the tax-benefit microsimulation model and econometric methods, on 2007 Living Standard Measurement Survey data. The empirical analysis is based on novel assumption that individual's tax evasion decision depends on a change in disposable income, which is captured by the variation in their Effective Marginal Tax Rates (EMTR, rather than on a change in after-tax income. The results suggest that the elasticity of tax evasion to EMTR equals -0.3, confirming the Yitzhaki's theory, while the propensity to evade is decreasing in the level of wages and increasing in the level of self-employment income. The results also show that introduction of revenue-neutral, progressive taxation of labour income would lead to increase in labour tax evasion by 1 percentage point.

  11. Fast distributed strategic learning for global optima in queueing access games

    KAUST Repository

    Tembine, Hamidou

    2014-01-01

    In this paper we examine combined fully distributed payoff and strategy learning (CODIPAS) in a queue-aware access game over a graph. The classical strategic learning analysis relies on vanishing or small learning rate and uses stochastic

  12. Tax Evasion and the Impact on Economic Growth Acta Universitatis Danubius. OEconomica

    Directory of Open Access Journals (Sweden)

    Shkendije Demalijaj Ukaj

    2014-12-01

    Full Text Available The level of taxation is very important for the development of current and future of a country and fiscal policy should always be considered as an important factor in the behavior of participants and their ability to tax evasion and informality. Government fiscal policies can trigger tax increase under pressure, especially in situations such as economic crisis, inflation, unemployment, instability, when the burden of this obligation grows, its effects are considered to take them to tax evasion and informality (Dragomir. et al. 2011. However, these reasons do not relate to all the great presence of this phenomenon in Kosovo, taking into account the recent economic crisis has not reflected in the economy of Kosovo and the Kosovo tax burden is among the lowest in the region, but leading cause of tax evasion and informality can be considered above the corruption of public administration officials including tax and customs officials, insufficient staff for his fighting, weak rule of law, as well as lower fiscal culture for paying taxes. For this reason the scope of this paper will be the theoretical treatment of the informal economy and tax evasion in view of tax avoidance, meaning, characteristics and their effects on the economy and possible recommendations on these viewpoints.

  13. An ensemble based nonlinear orthogonal matching pursuit algorithm for sparse history matching of reservoir models

    KAUST Repository

    Fsheikh, Ahmed H.

    2013-01-01

    A nonlinear orthogonal matching pursuit (NOMP) for sparse calibration of reservoir models is presented. Sparse calibration is a challenging problem as the unknowns are both the non-zero components of the solution and their associated weights. NOMP is a greedy algorithm that discovers at each iteration the most correlated components of the basis functions with the residual. The discovered basis (aka support) is augmented across the nonlinear iterations. Once the basis functions are selected from the dictionary, the solution is obtained by applying Tikhonov regularization. The proposed algorithm relies on approximate gradient estimation using an iterative stochastic ensemble method (ISEM). ISEM utilizes an ensemble of directional derivatives to efficiently approximate gradients. In the current study, the search space is parameterized using an overcomplete dictionary of basis functions built using the K-SVD algorithm.

  14. The Underground Economy and Tax Evasion in Pakistan. A Fresh Assessment

    OpenAIRE

    Zafar Iqbal; Sarfraz Khan Qureshi; Riaz Mahmood

    1998-01-01

    This paper assesses the size of the underground ~conomy and tax evasion in Pakistan for the period 1973-96. Using monetary approach, the results confirm the existence of large underground economy and higher tax evasion over the period under analysis. The overall underground economy has remarkably increased from 20 percent of GDP in 1973 to 51 percent of GDP in 1996. The evidence also suggests that the rate of growth in th~ underground economy has been higher than the rate of growth of the for...

  15. Lapse of time effects on tax evasion in an agent-based econophysics model

    Science.gov (United States)

    Seibold, Götz; Pickhardt, Michael

    2013-05-01

    We investigate an inhomogeneous Ising model in the context of tax evasion dynamics where different types of agents are parameterized via local temperatures and magnetic fields. In particular, we analyze the impact of lapse of time effects (i.e. backauditing) and endogenously determined penalty rates on tax compliance. Both features contribute to a microfoundation of agent-based econophysics models of tax evasion.

  16. International Tax Evasion, State Purchases of Confidential Bank Data and Voluntary Disclosures

    OpenAIRE

    Bethmann, Dirk; Kvasnicka, Michael

    2017-01-01

    State purchases of bank data on suspected tax evaders from international tax havens constitute a potential tool to combat international tax evasion. Using self-compiled data for North-Rhine Westphalia on the timing and content of such data acquisitions from whistleblowers and on monthly voluntary disclosures of international tax evasion involving Swiss banks, we show that purchases of data by tax authorities on potential tax evaders have a positive and sizeable effect on voluntary disclosures.

  17. Viral evasion of DNA-stimulated innate immune responses

    Science.gov (United States)

    Christensen, Maria H; Paludan, Søren R

    2017-01-01

    Cellular sensing of virus-derived nucleic acids is essential for early defenses against virus infections. In recent years, the discovery of DNA sensing proteins, including cyclic GMP–AMP synthase (cGAS) and gamma-interferon-inducible protein (IFI16), has led to understanding of how cells evoke strong innate immune responses against incoming pathogens carrying DNA genomes. The signaling stimulated by DNA sensors depends on the adaptor protein STING (stimulator of interferon genes), to enable expression of antiviral proteins, including type I interferon. To facilitate efficient infections, viruses have evolved a wide range of evasion strategies, targeting host DNA sensors, adaptor proteins and transcription factors. In this review, the current literature on virus-induced activation of the STING pathway is presented and we discuss recently identified viral evasion mechanisms targeting different steps in this antiviral pathway. PMID:26972769

  18. Security Strategies of Both Players in Asymmetric Information Zero-Sum Stochastic Games with an Informed Controller

    KAUST Repository

    Li, Lichun

    2017-11-07

    This paper considers a zero-sum two-player asymmetric information stochastic game where only one player knows the system state, and the transition law is controlled by the informed player only. For the informed player, it has been shown that the security strategy only depends on the belief and the current stage. We provide LP formulations whose size is only linear in the size of the uninformed player\\'s action set to compute both history based and belief based security strategies. For the uninformed player, we focus on the regret, the difference between 0 and the future payoff guaranteed by the uninformed player in every possible state. Regret is a real vector of the same size as the belief, and depends only on the action of the informed player and the strategy of the uninformed player. This paper shows that the uninformed player has a security strategy that only depends on the regret and the current stage. LP formulations are then given to compute the history based security strategy, the regret at every stage, and the regret based security strategy. The size of the LP formulations are again linear in the size of the uninformed player action set. Finally, an intrusion detection problem is studied to demonstrate the main results in this paper.

  19. A subexponential lower bound for the Random Facet algorithm for Parity Games

    DEFF Research Database (Denmark)

    Friedmann, Oliver; Hansen, Thomas Dueholm; Zwick, Uri

    2011-01-01

    Parity Games form an intriguing family of infinite duration games whose solution is equivalent to the solution of important problems in automatic verification and automata theory. They also form a very natural subclass of Deterministic Mean Payoff Games, which in turn is a very natural subclass...... of turn-based Stochastic Mean Payoff Games. It is a major open problem whether these game families can be solved in polynomial time. The currently theoretically fastest algorithms for the solution of all these games are adaptations of the randomized algorithms of Kalai and of Matouˇsek, Sharir and Welzl...... for LP-type problems, an abstract generalization of linear programming. The expected running time of both algorithms is subexponential in the size of the game, i.e., 2O(√n log n), where n is the number of vertices in the game. We focus in this paper on the algorithm of Matouˇsek, Sharir and Welzl...

  20. Assessment of working women's perception and pursuit of recreation

    African Journals Online (AJOL)

    Assessment of working women's perception and pursuit of recreation. ... Africa, to participate in two focus group interviews at the workplace of the respondents. ... Three underlying themes, namely barriers, benefits, and attitude and pursuits ...

  1. Functional motifs responsible for human metapneumovirus M2-2-mediated innate immune evasion.

    Science.gov (United States)

    Chen, Yu; Deng, Xiaoling; Deng, Junfang; Zhou, Jiehua; Ren, Yuping; Liu, Shengxuan; Prusak, Deborah J; Wood, Thomas G; Bao, Xiaoyong

    2016-12-01

    Human metapneumovirus (hMPV) is a major cause of lower respiratory infection in young children. Repeated infections occur throughout life, but its immune evasion mechanisms are largely unknown. We recently found that hMPV M2-2 protein elicits immune evasion by targeting mitochondrial antiviral-signaling protein (MAVS), an antiviral signaling molecule. However, the molecular mechanisms underlying such inhibition are not known. Our mutagenesis studies revealed that PDZ-binding motifs, 29-DEMI-32 and 39-KEALSDGI-46, located in an immune inhibitory region of M2-2, are responsible for M2-2-mediated immune evasion. We also found both motifs prevent TRAF5 and TRAF6, the MAVS downstream adaptors, to be recruited to MAVS, while the motif 39-KEALSDGI-46 also blocks TRAF3 migrating to MAVS. In parallel, these TRAFs are important in activating transcription factors NF-kB and/or IRF-3 by hMPV. Our findings collectively demonstrate that M2-2 uses its PDZ motifs to launch the hMPV immune evasion through blocking the interaction of MAVS and its downstream TRAFs. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Stochastic anomaly detection in eye-tracking data for quantification of motor symptoms in Parkinson's disease

    Science.gov (United States)

    Jansson, Daniel; Medvedev, Alexander; Axelson, Hans; Nyholm, Dag

    2013-10-01

    Two methods for distinguishing between healthy controls and patients diagnosed with Parkinson's disease by means of recorded smooth pursuit eye movements are presented and evaluated. Both methods are based on the principles of stochastic anomaly detection and make use of orthogonal series approximation for probability distribution estimation. The first method relies on the identification of a Wiener-type model of the smooth pursuit system and attempts to find statistically significant differences between the estimated parameters in healthy controls and patientts with Parkinson's disease. The second method applies the same statistical method to distinguish between the gaze trajectories of healthy and Parkinson subjects attempting to track visual stimuli. Both methods show promising results, where healthy controls and patients with Parkinson's disease are effectively separated in terms of the considered metric. The results are preliminary because of the small number of participating test subjects, but they are indicative of the potential of the presented methods as diagnosing or staging tools for Parkinson's disease.

  3. Evasion of adaptive and innate immune response mechanisms by γ-herpesviruses

    Science.gov (United States)

    Feng, Pinghui; Moses, Ashlee; Früh, Klaus

    2015-01-01

    γ-Herpesviral immune evasion mechanisms are optimized to support the acute, lytic and the longterm, latent phase of infection. During acute infection, specific immune modulatory proteins limit, but also exploit, the antiviral activities of cell intrinsic innate immune responses as well as those of innate and adaptive immune cells. During latent infection, a restricted gene expression program limits immune targeting and cis-acting mechanisms to reduce the antigen presentation as well as antigenicity of latency-associated proteins. Here, we will review recent progress in our understanding of γ-herpesviral immune evasion strategies. PMID:23735334

  4. Solving Stochastic Büchi Games on Infinite Arenas with a Finite Attractor

    Directory of Open Access Journals (Sweden)

    Nathalie Bertrand

    2013-06-01

    Full Text Available We consider games played on an infinite probabilistic arena where the first player aims at satisfying generalized Büchi objectives almost surely, i.e., with probability one. We provide a fixpoint characterization of the winning sets and associated winning strategies in the case where the arena satisfies the finite-attractor property. From this we directly deduce the decidability of these games on probabilistic lossy channel systems.

  5. Conservation of a unique mechanism of immune evasion across the Lyssavirus genus.

    Science.gov (United States)

    Wiltzer, L; Larrous, F; Oksayan, S; Ito, N; Marsh, G A; Wang, L F; Blondel, D; Bourhy, H; Jans, D A; Moseley, G W

    2012-09-01

    The evasion of host innate immunity by Rabies virus, the prototype of the genus Lyssavirus, depends on a unique mechanism of selective targeting of interferon-activated STAT proteins by the viral phosphoprotein (P-protein). However, the immune evasion strategies of other lyssaviruses, including several lethal human pathogens, are unresolved. Here, we show that this mechanism is conserved between the most distantly related members of the genus, providing important insights into the pathogenesis and potential therapeutic targeting of lyssaviruses.

  6. Estimation of tax evasion and the effectiveness of tax collection for Thailand

    OpenAIRE

    Janbunjong, Pichit

    2009-01-01

    ABSTRACT Low tax revenue is an acute problem for the Thai Government, one which causes a lack of funds for much needed economic and social development. The cause of the low tax revenue is ineffective tax administration. Thus the purpose of this research was to measure the tax effectiveness in Thailand. The review presents the popular Tanzi’s monetary approach for estimating the level of tax evasion and it has resulted in the hypothesis that tax evasion generally increases ...

  7. Neurophysiology and Neuroanatomy of Smooth Pursuit: Lesion Studies

    Science.gov (United States)

    Sharpe, James A.

    2008-01-01

    Smooth pursuit impairment is recognized clinically by the presence of saccadic tracking of a small object and quantified by reduction in pursuit gain, the ratio of smooth eye movement velocity to the velocity of a foveal target. Correlation of the site of brain lesions, identified by imaging or neuropathological examination, with defective smooth…

  8. Evidence for object permanence in the smooth-pursuit eye movements of monkeys.

    Science.gov (United States)

    Churchland, Mark M; Chou, I-Han; Lisberger, Stephen G

    2003-10-01

    We recorded the smooth-pursuit eye movements of monkeys in response to targets that were extinguished (blinked) for 200 ms in mid-trajectory. Eye velocity declined considerably during the target blinks, even when the blinks were completely predictable in time and space. Eye velocity declined whether blinks were presented during steady-state pursuit of a constant-velocity target, during initiation of pursuit before target velocity was reached, or during eye accelerations induced by a change in target velocity. When a physical occluder covered the trajectory of the target during blinks, creating the impression that the target moved behind it, the decline in eye velocity was reduced or abolished. If the target was occluded once the eye had reached target velocity, pursuit was only slightly poorer than normal, uninterrupted pursuit. In contrast, if the target was occluded during the initiation of pursuit, while the eye was accelerating toward target velocity, pursuit during occlusion was very different from normal pursuit. Eye velocity remained relatively stable during target occlusion, showing much less acceleration than normal pursuit and much less of a decline than was produced by a target blink. Anticipatory or predictive eye acceleration was typically observed just prior to the reappearance of the target. Computer simulations show that these results are best understood by assuming that a mechanism of eye-velocity memory remains engaged during target occlusion but is disengaged during target blinks.

  9. Gaming of performance measurement in health care: parallels with tax compliance.

    Science.gov (United States)

    Mears, Alex; Webley, Paul

    2010-10-01

    Gaming of performance measurement in health care distorts performance, making it appear better than it is. This can conceal potentially hazardous practice and endanger patients and staff. Research has investigated and categorized this behaviour but as yet has offered little in the way of potential solutions as the drivers are still not well understood. Studies of the psychology of tax behaviour, specifically tax avoidance and evasion, reveal some insights into what the underlying causes are. Looking at health care and tax compliance, seven similarities in response can be detected: negative view of those subject to it; not salient except for specific classes of people; general understanding of the need versus resentment of actuality; cognitive dissonance; moral versus legal grey areas; two levels of objective non-compliance; and four categories of subjective behaviour and attitude. We suggest a model of reaction and compliance for gaming and offer some suggestions as to how this phenomenon might be minimized.

  10. Considering individual satisfaction levels enhances cooperation in a spatial prisoner’s dilemma game

    International Nuclear Information System (INIS)

    Tanimoto, Jun

    2015-01-01

    Highlights: • A new model for the SPD game considering an individual’s satisfaction level is presented. • Simulation results show a non-trivial enhancement of cooperation. • The enhancement found results from a stochastic resonance effect. - Abstract: Based on the observance in human society, the satisfaction level of an individual as a result of an obtained payoff depends on personal tendency to some extent; we establish a new model for spatial prisoner’s dilemma games. We describe individual satisfaction as a stochastically deviated value around each of the four payoffs stipulated by a payoff matrix, which is maintained throughout the life of a certain agent. When strategy updating, an agent who refers to his own satisfaction level cannot see neighbors’ satisfaction levels but can only observe neighbors’ accumulated payoffs. By varying the update rule and underlying topology, we perform numerical simulations that reveal cooperation is significantly enhanced by this change. We argue that this enhancement of cooperation is analogous to a stochastic resonance effect, like the payoff noise effects Perc (2006).

  11. An update: Epstein-Barr virus and immune evasion via microRNA regulation.

    Science.gov (United States)

    Zuo, Lielian; Yue, Wenxin; Du, Shujuan; Xin, Shuyu; Zhang, Jing; Liu, Lingzhi; Li, Guiyuan; Lu, Jianhong

    2017-06-01

    Epstein-Barr virus (EBV) is an oncogenic virus that ubiquitously establishes life-long persistence in humans. To ensure its survival and maintain its B cell transformation function, EBV has developed powerful strategies to evade host immune responses. Emerging evidence has shown that microRNAs (miRNAs) are powerful regulators of the maintenance of cellular homeostasis. In this review, we summarize current progress on how EBV utilizes miRNAs for immune evasion. EBV encodes miRNAs targeting both viral and host genes involved in the immune response. The miRNAs are found in two gene clusters, and recent studies have demonstrated that lack of these clusters increases the CD4 + and CD8 + T cell response of infected cells. These reports strongly indicate that EBV miRNAs are critical for immune evasion. In addition, EBV is able to dysregulate the expression of a variety of host miRNAs, which influence multiple immune-related molecules and signaling pathways. The transport via exosomes of EBV-regulated miRNAs and viral proteins contributes to the construction and modification of the inflammatory tumor microenvironment. During EBV immune evasion, viral proteins, immune cells, chemokines, pro-inflammatory cytokines, and pro-apoptosis molecules are involved. Our increasing knowledge of the role of miRNAs in immune evasion will improve the understanding of EBV persistence and help to develop new treatments for EBV-associated cancers and other diseases.

  12. Value added tax evasion and excise duty fraud on fuel market in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Pavel Semerád

    2012-01-01

    Full Text Available This paper deals with analysis of current problems in the motor fuel market. It analyzes bottlenecks in setting the legislative changes in value added tax, excise tax and the legislation concerning fuels. The biggest problem is tax evasions that favor one group of business entities at the expense of another, and also cause that the state loses revenues mainly from indirect taxes. Therefore, attention is directed to quality control of fuels as a means of consumer protection and prevention of tax evasion and ways to combat tax evasion in import, distribution and storage of mineral oils. The examples are the most common errors found in fraudulent companies. Based on the data collected the possible ultimate evasion was estimated. Therefore, I propose that value added tax law should be amended and some other measures to improve supervision by public authorities like tax authorities and customs administration offices should be taken.

  13. Itemised Deductions : A Device to Reduce Tax Evasion

    NARCIS (Netherlands)

    Piolatto, A.

    2010-01-01

    Direct incentives and punishments are the most common instruments to fight tax evasion. The theoretical literature disregarded indirect schemes, such as itemised deductions, in which an agent has an interest in that other agents declare their revenue. Itemised deductions provide an incentive for

  14. Transient Response Analysis of Metropolis Learning in Games

    KAUST Repository

    Jaleel, Hassan

    2017-10-19

    The objective of this work is to provide a qualitative description of the transient properties of stochastic learning dynamics like adaptive play, log-linear learning, and Metropolis learning. The solution concept used in these learning dynamics for potential games is that of stochastic stability, which is based on the stationary distribution of the reversible Markov chain representing the learning process. However, time to converge to a stochastically stable state is exponential in the inverse of noise, which limits the use of stochastic stability as an effective solution concept for these dynamics. We propose a complete solution concept that qualitatively describes the state of the system at all times. The proposed concept is prevalent in control systems literature where a solution to a linear or a non-linear system has two parts, transient response and steady state response. Stochastic stability provides the steady state response of stochastic learning rules. In this work, we study its transient properties. Starting from an initial condition, we identify the subsets of the state space called cycles that have small hitting times and long exit times. Over the long time scales, we provide a description of how the distributions over joint action profiles transition from one cycle to another till it reaches the globally optimal state.

  15. Transient Response Analysis of Metropolis Learning in Games

    KAUST Repository

    Jaleel, Hassan; Shamma, Jeff S.

    2017-01-01

    The objective of this work is to provide a qualitative description of the transient properties of stochastic learning dynamics like adaptive play, log-linear learning, and Metropolis learning. The solution concept used in these learning dynamics for potential games is that of stochastic stability, which is based on the stationary distribution of the reversible Markov chain representing the learning process. However, time to converge to a stochastically stable state is exponential in the inverse of noise, which limits the use of stochastic stability as an effective solution concept for these dynamics. We propose a complete solution concept that qualitatively describes the state of the system at all times. The proposed concept is prevalent in control systems literature where a solution to a linear or a non-linear system has two parts, transient response and steady state response. Stochastic stability provides the steady state response of stochastic learning rules. In this work, we study its transient properties. Starting from an initial condition, we identify the subsets of the state space called cycles that have small hitting times and long exit times. Over the long time scales, we provide a description of how the distributions over joint action profiles transition from one cycle to another till it reaches the globally optimal state.

  16. Stochastic collusion and the power law of learning: a general reinforcement learning model of cooperation

    NARCIS (Netherlands)

    Flache, A.

    2002-01-01

    Concerns about models of cultural adaptation as analogs of genetic selection have led cognitive game theorists to explore learning-theoretic specifications. Two prominent examples, the Bush-Mosteller stochastic learning model and the Roth-Erev payoff-matching model, are aligned and integrated as

  17. CAUSES OF TAX EVASION AND HOW TO REDUCE IT

    Directory of Open Access Journals (Sweden)

    Marcel ȘUVELEA

    2014-12-01

    Full Text Available The level of taxation is influenced and determined by several factors such as: the performance of the economy at any given time, the effectiveness of financed from taxes public expenditure, property structure, public needs as determined by Government policy and approved by the Parliament, the degree of contributors’ understanding of budgetary needs and adherence to Government policy, the stage of democracy in one country or another, etc. These make that between tax level and its base, represented by the GDP, not to be a strict correlation On the State budget and public finance, the cases of tax evasion or avoidance may not have manifested but negative effects. In reality, even the potentiality of cases of tax evasion by taxpayers, adversely affect public funds through the necessary expenditure to be earmarked for the prevention and monitoring of the tax payers. The higher is the extent of the phenomenon of tax evasion, the more the public finances of a State will suffer. If this phenomenon is joined by a weak economy and a shaky fiscal system, the negative effects are augmented. It should also be pointed out another important aspect of feeble public finances: chances are that fiscal bodies to act in that tough situation under emergency and pressure status and to deceive this tension on the economy, making it more unfit to uphold degraded public finances.

  18. Conservation of a Unique Mechanism of Immune Evasion across the Lyssavirus Genus

    Science.gov (United States)

    Wiltzer, L.; Larrous, F.; Oksayan, S.; Ito, N.; Marsh, G. A.; Wang, L. F.; Blondel, D.; Bourhy, H.; Jans, D. A.

    2012-01-01

    The evasion of host innate immunity by Rabies virus, the prototype of the genus Lyssavirus, depends on a unique mechanism of selective targeting of interferon-activated STAT proteins by the viral phosphoprotein (P-protein). However, the immune evasion strategies of other lyssaviruses, including several lethal human pathogens, are unresolved. Here, we show that this mechanism is conserved between the most distantly related members of the genus, providing important insights into the pathogenesis and potential therapeutic targeting of lyssaviruses. PMID:22740405

  19. Exogenous empirical-evidence equilibria in perfect-monitoring repeated games yield correlated equilibria

    KAUST Repository

    Dudebout, Nicolas; Shamma, Jeff S.

    2014-01-01

    This paper proves that exogenous empirical-evidence equilibria (xEEEs) in perfect-monitoring repeated games induce correlated equilibria of the associated one-shot game. An empirical-evidence equilibrium (EEE) is a solution concept for stochastic games. At equilibrium, agents' strategies are optimal with respect to models of their opponents. These models satisfy a consistency condition with respect to the actual behavior of the opponents. As such, EEEs replace the full-rationality requirement of Nash equilibria by a consistency-based bounded-rationality one. In this paper, the framework of empirical evidence is summarized, with an emphasis on perfect-monitoring repeated games. A less constraining notion of consistency is introduced. The fact that an xEEE in a perfect-monitoring repeated game induces a correlated equilibrium on the underlying one-shot game is proven. This result and the new notion of consistency are illustrated on the hawk-dove game. Finally, a method to build specific correlated equilibria from xEEEs is derived.

  20. Exogenous empirical-evidence equilibria in perfect-monitoring repeated games yield correlated equilibria

    KAUST Repository

    Dudebout, Nicolas

    2014-12-15

    This paper proves that exogenous empirical-evidence equilibria (xEEEs) in perfect-monitoring repeated games induce correlated equilibria of the associated one-shot game. An empirical-evidence equilibrium (EEE) is a solution concept for stochastic games. At equilibrium, agents\\' strategies are optimal with respect to models of their opponents. These models satisfy a consistency condition with respect to the actual behavior of the opponents. As such, EEEs replace the full-rationality requirement of Nash equilibria by a consistency-based bounded-rationality one. In this paper, the framework of empirical evidence is summarized, with an emphasis on perfect-monitoring repeated games. A less constraining notion of consistency is introduced. The fact that an xEEE in a perfect-monitoring repeated game induces a correlated equilibrium on the underlying one-shot game is proven. This result and the new notion of consistency are illustrated on the hawk-dove game. Finally, a method to build specific correlated equilibria from xEEEs is derived.

  1. Spatial Evolutionary Games of Interaction among Generic Cancer Cells

    DEFF Research Database (Denmark)

    Bach, Lars Arve; Sumpter, David J.T.; Alsner, Jan

    2003-01-01

    Evolutionary game models of cellular interactions have shown that heterogeneity in the cellular genotypic composition is maintained through evolution to stable coexistence of growth-promoting and non-promoting cell types. We generalise these mean-field models and relax the assumption of perfect...... mixing of cells by instead implementing an individual-based model that includes the stochastic and spatial effects likely to occur in tumours. The scope for coexistence of genotypic strategies changed with the inclusion of explicit space and stochasticity. The spatial models show some interesting...... deviations from their mean-field counterparts, for example the possibility of altruistic (paracrine) cell strategies to thrive. Such effects can however, be highly sensitive to model implementation and the more realistic models with semi-synchronous and stochastic updating do not show evolution of altruism...

  2. Evasion of added isotopic mercury from a northern temperate lake

    Science.gov (United States)

    Southworth, G.; Lindberg, S.; Hintelmann, H.; Amyot, M.; Poulain, A.; Bogle, M.; Peterson, M.; Rudd, J.; Harris, R.; Sandilands, K.; Krabbenhoft, D.; Olsen, M.

    2007-01-01

    Isotopically enriched Hg (90% 202Hg) was added to a small lake in Ontario, Canada, at a rate equivalent to approximately threefold the annual direct atmospheric deposition rate that is typical of the northeastern United States. The Hg spike was thoroughly mixed into the epilimnion in nine separate events at two-week intervals throughout the summer growing season for three consecutive years. We measured concentrations of spike and ambient dissolved gaseous Hg (DGM) concentrations in surface water and the rate of volatilization of Hg from the lake on four separate, week-long sampling periods using floating dynamic flux chambers. The relationship between empirically measured rates of spike-Hg evasion were evaluated as functions of DGM concentration, wind velocity, and solar illumination. No individual environmental variable proved to be a strong predictor of the evasion flux. The DGM-normalized flux (expressed as the mass transfer coefficient, k) varied with wind velocity in a manner consistent with existing models of evasion of volatile solutes from natural waters but was higher than model estimates at low wind velocity. The empirical data were used to construct a description of evasion flux as a function of total dissolved Hg, wind, and solar illumination. That model was then applied to data for three summers for the experiment to generate estimates of Hg re-emission from the lake surface to the atmosphere. Based on ratios of spike Hg to ambient Hg in DGM and dissolved total Hg pools, ratios of DGM to total Hg in spike and ambient Hg pools, and flux estimates of spike and ambient Hg, we concluded that the added Hg spike was chemically indistinguishable from the ambient Hg in its behavior. Approximately 45% of Hg added to the lake over the summer was lost via volatilization. ?? 2007 SETAC.

  3. Avoiding evasion: medical ethics education and emotion theory.

    NARCIS (Netherlands)

    Leget, C.J.W.

    2004-01-01

    Beginning with an exemplary case study, this paper diagnoses and analyses some important strategies of evasion and factors of hindrance that are met in the teaching of medical ethics to undergraduate medical students. Some of these inhibitions are inherent to ethical theories; others are connected

  4. HackAttack: Game-Theoretic Analysis of Realistic Cyber Conflicts

    Energy Technology Data Exchange (ETDEWEB)

    Ferragut, Erik M [ORNL; Brady, Andrew C [Jefferson Middle School, Oak Ridge, TN; Brady, Ethan J [Oak Ridge High School, Oak Ridge, TN; Ferragut, Jacob M [Oak Ridge High School, Oak Ridge, TN; Ferragut, Nathan M [Oak Ridge High School, Oak Ridge, TN; Wildgruber, Max C [ORNL

    2016-01-01

    Game theory is appropriate for studying cyber conflict because it allows for an intelligent and goal-driven adversary. Applications of game theory have led to a number of results regarding optimal attack and defense strategies. However, the overwhelming majority of applications explore overly simplistic games, often ones in which each participant s actions are visible to every other participant. These simplifications strip away the fundamental properties of real cyber conflicts: probabilistic alerting, hidden actions, unknown opponent capabilities. In this paper, we demonstrate that it is possible to analyze a more realistic game, one in which different resources have different weaknesses, players have different exploits, and moves occur in secrecy, but they can be detected. Certainly, more advanced and complex games are possible, but the game presented here is more realistic than any other game we know of in the scientific literature. While optimal strategies can be found for simpler games using calculus, case-by-case analysis, or, for stochastic games, Q-learning, our more complex game is more naturally analyzed using the same methods used to study other complex games, such as checkers and chess. We define a simple evaluation function and employ multi-step searches to create strategies. We show that such scenarios can be analyzed, and find that in cases of extreme uncertainty, it is often better to ignore one s opponent s possible moves. Furthermore, we show that a simple evaluation function in a complex game can lead to interesting and nuanced strategies.

  5. Stochastic population dynamics in spatially extended predator-prey systems

    Science.gov (United States)

    Dobramysl, Ulrich; Mobilia, Mauro; Pleimling, Michel; Täuber, Uwe C.

    2018-02-01

    Spatially extended population dynamics models that incorporate demographic noise serve as case studies for the crucial role of fluctuations and correlations in biological systems. Numerical and analytic tools from non-equilibrium statistical physics capture the stochastic kinetics of these complex interacting many-particle systems beyond rate equation approximations. Including spatial structure and stochastic noise in models for predator-prey competition invalidates the neutral Lotka-Volterra population cycles. Stochastic models yield long-lived erratic oscillations stemming from a resonant amplification mechanism. Spatially extended predator-prey systems display noise-stabilized activity fronts that generate persistent correlations. Fluctuation-induced renormalizations of the oscillation parameters can be analyzed perturbatively via a Doi-Peliti field theory mapping of the master equation; related tools allow detailed characterization of extinction pathways. The critical steady-state and non-equilibrium relaxation dynamics at the predator extinction threshold are governed by the directed percolation universality class. Spatial predation rate variability results in more localized clusters, enhancing both competing species’ population densities. Affixing variable interaction rates to individual particles and allowing for trait inheritance subject to mutations induces fast evolutionary dynamics for the rate distributions. Stochastic spatial variants of three-species competition with ‘rock-paper-scissors’ interactions metaphorically describe cyclic dominance. These models illustrate intimate connections between population dynamics and evolutionary game theory, underscore the role of fluctuations to drive populations toward extinction, and demonstrate how space can support species diversity. Two-dimensional cyclic three-species May-Leonard models are characterized by the emergence of spiraling patterns whose properties are elucidated by a mapping onto a complex

  6. FEFsem neuronal response during combined volitional and reflexive pursuit.

    Science.gov (United States)

    Bakst, Leah; Fleuriet, Jérome; Mustari, Michael J

    2017-05-01

    Although much is known about volitional and reflexive smooth eye movements individually, much less is known about how they are coordinated. It is hypothesized that separate cortico-ponto-cerebellar loops subserve these different types of smooth eye movements. Specifically, the MT-MST-DLPN pathway is thought to be critical for ocular following eye movements, whereas the FEF-NRTP pathway is understood to be vital for volitional smooth pursuit. However, the role that these loops play in combined volitional and reflexive behavior is unknown. We used a large, textured background moving in conjunction with a small target spot to investigate the eye movements evoked by a combined volitional and reflexive pursuit task. We also assessed the activity of neurons in the smooth eye movement subregion of the frontal eye field (FEFsem). We hypothesized that the pursuit system would show less contribution from the volitional pathway in this task, owing to the increased involvement of the reflexive pathway. In accordance with this hypothesis, a majority of FEFsem neurons (63%) were less active during pursuit maintenance in a combined volitional and reflexive pursuit task than during purely volitional pursuit. Interestingly and surprisingly, the neuronal response to the addition of the large-field motion was highly correlated with the neuronal response to a target blink. This suggests that FEFsem neuronal responses to these different perturbations-whether the addition or subtraction of retinal input-may be related. We conjecture that these findings are due to changing weights of both the volitional and reflexive pathways, as well as retinal and extraretinal signals.

  7. Bribes and Business Tax Evasion

    Directory of Open Access Journals (Sweden)

    Joulfaian, David

    2009-12-01

    Full Text Available This paper investigates the role of governance, in particular bribes to tax officials, in shaping business tax compliance behavior in transition economies. The empirical results show that business noncompliance rises with the frequency of tax related bribes. More specifically, the findings from 27 economies suggest that tax evasion thrives when bribes to tax officials are commonplace. These findings are robust to a number of specifications that control for firm and country attributes as well as address the potential endogeneity of bribes.

  8. Nonlinear analysis of the cooperation of strategic alliances through stochastic catastrophe theory

    Science.gov (United States)

    Xu, Yan; Hu, Bin; Wu, Jiang; Zhang, Jianhua

    2014-04-01

    The excitation intervention of strategic alliance may change with the changes in the parameters of circumstance (e.g., external alliance tasks). As a result, the stable cooperation between members may suffer a complete unplanned betrayal at last. However, current perspectives on strategic alliances cannot adequately explain this transition mechanism. This study is a first attempt to analyze this nonlinear phenomenon through stochastic catastrophe theory (SCT). A stochastic dynamics model is constructed based on the cooperation of strategic alliance from the perspective of evolutionary game theory. SCT explains the discontinuous changes caused by the changes in environmental parameters. Theoretically, we identify conditions where catastrophe can occur in the cooperation of alliance members.

  9. Dynamics in atomic signaling games

    KAUST Repository

    Fox, Michael J.

    2015-04-08

    We study an atomic signaling game under stochastic evolutionary dynamics. There are a finite number of players who repeatedly update from a finite number of available languages/signaling strategies. Players imitate the most fit agents with high probability or mutate with low probability. We analyze the long-run distribution of states and show that, for sufficiently small mutation probability, its support is limited to efficient communication systems. We find that this behavior is insensitive to the particular choice of evolutionary dynamic, a property that is due to the game having a potential structure with a potential function corresponding to average fitness. Consequently, the model supports conclusions similar to those found in the literature on language competition. That is, we show that efficient languages eventually predominate the society while reproducing the empirical phenomenon of linguistic drift. The emergence of efficiency in the atomic case can be contrasted with results for non-atomic signaling games that establish the non-negligible possibility of convergence, under replicator dynamics, to states of unbounded efficiency loss.

  10. Dynamics in atomic signaling games

    KAUST Repository

    Fox, Michael J.; Touri, Behrouz; Shamma, Jeff S.

    2015-01-01

    We study an atomic signaling game under stochastic evolutionary dynamics. There are a finite number of players who repeatedly update from a finite number of available languages/signaling strategies. Players imitate the most fit agents with high probability or mutate with low probability. We analyze the long-run distribution of states and show that, for sufficiently small mutation probability, its support is limited to efficient communication systems. We find that this behavior is insensitive to the particular choice of evolutionary dynamic, a property that is due to the game having a potential structure with a potential function corresponding to average fitness. Consequently, the model supports conclusions similar to those found in the literature on language competition. That is, we show that efficient languages eventually predominate the society while reproducing the empirical phenomenon of linguistic drift. The emergence of efficiency in the atomic case can be contrasted with results for non-atomic signaling games that establish the non-negligible possibility of convergence, under replicator dynamics, to states of unbounded efficiency loss.

  11. Does the sole description of a tax authority affect tax evasion?--the impact of described coercive and legitimate power.

    Science.gov (United States)

    Hartl, Barbara; Hofmann, Eva; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

    2015-01-01

    Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority's power. Descriptions of the tax authority's power may affect taxpayers' beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority's power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority's power on participants' beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants' beliefs regarding tax authority's power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority's power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information.

  12. Does the sole description of a tax authority affect tax evasion?--the impact of described coercive and legitimate power.

    Directory of Open Access Journals (Sweden)

    Barbara Hartl

    Full Text Available Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority's power. Descriptions of the tax authority's power may affect taxpayers' beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority's power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority's power on participants' beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2, legitimate power (Experiment 3, and coercive and legitimate power combined (Experiment 4. Further, it is examined whether a contrast of the description of power (low to high power; high to low power impacts tax evasion (Experiments 2-4. Results show that the amount of fine does not impact tax payments, whereas participants' beliefs regarding tax authority's power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority's power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information.

  13. Disease dynamics in a stochastic network game: a little empathy goes a long way in averting outbreaks

    KAUST Repository

    Eksin, Ceyhun

    2017-03-14

    Individuals change their behavior during an epidemic in response to whether they and/or those they interact with are healthy or sick. Healthy individuals may utilize protective measures to avoid contracting a disease. Sick individuals may utilize preemptive measures to avoid spreading a disease. Yet, in practice both protective and preemptive changes in behavior come with costs. This paper proposes a stochastic network disease game model that captures the self-interests of individuals during the spread of a susceptible-infected-susceptible disease. In this model, individuals strategically modify their behavior based on current disease conditions. These reactions influence disease spread. We show that there is a critical level of concern, i.e., empathy, by the sick individuals above which disease is eradicated rapidly. Furthermore, we find that risk averse behavior by the healthy individuals cannot eradicate the disease without the preemptive measures of the sick individuals. Empathy is more effective than risk-aversion because when infectious individuals change behavior, they reduce all of their potential infections, whereas when healthy individuals change behavior, they reduce only a small portion of potential infections. This imbalance in the role played by the response of the infected versus the susceptible individuals on disease eradication affords critical policy insights.

  14. Tax Evasion Causes and Prevenience or Rebutment Way of Tax Dodger Phenomenon

    Directory of Open Access Journals (Sweden)

    Corina Nichitcin

    2010-12-01

    Full Text Available Tax evasion phenomenon, having negative impact on many levels, must be constantly pursued in order to minimize tax circumvention and control section in the issue of tax fraud. From international theory and experience it is known that normal functioning of market economy is conditioned by promotion of certain efficient policies and adequate legislation implementation. So, as Republic of Moldova is no exception among countries where tax evasion is, the study of this subject is up-to-date and it is required for presenting these problems at national and international levels.

  15. Backward stochastic differential equations with two distinct reflecting barriers and quadratic growth generator

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available We show the existence of a solution for the double-barrier reflected BSDE when the barriers are completely separate and the generator is continuous with quadratic growth. As an application, we solve the risk-sensitive mixed zero-sum stochastic differential game. In addition we deal with recallable options under Knightian uncertainty.

  16. Spirochetal Lipoproteins and Immune Evasion

    Science.gov (United States)

    Christodoulides, Alexei; Boyadjian, Ani; Kelesidis, Theodoros

    2017-01-01

    Spirochetes are a major threat to public health. However, the exact pathogenesis of spirochetal diseases remains unclear. Spirochetes express lipoproteins that often determine the cross talk between the host and spirochetes. Lipoproteins are pro-inflammatory, modulatory of immune responses, and enable the spirochetes to evade the immune system. In this article, we review the modulatory effects of spirochetal lipoproteins related to immune evasion. Understanding lipoprotein-induced immunomodulation will aid in elucidating innate pathogenesis processes and subsequent adaptive mechanisms potentially relevant to spirochetal disease vaccine development and treatment. PMID:28424696

  17. A comparative analysis of the factors of tax evasion in Ukraine and USA

    OpenAIRE

    N. Frolova

    2014-01-01

    The purpose of the article is to reveal effects on the individual's tax compliance, to examine weak points of tax legislation of Ukraine that may induce tax evasion, and to develop recommendations for the improvement of Ukraine's tax system in terms of minimization of tax evasion, in particular, by introducing comprehensive tax reporting. The article presents the findings of various theoretical and empiric investigations by leading domestic and foreign experts on the issues of estimation and ...

  18. Tax havens: Features, operations and solving tax evasion problems

    Directory of Open Access Journals (Sweden)

    Obradović-Ćuk Jelena

    2016-01-01

    Full Text Available Tax haven offers minimal or no tax liability to foreign individuals and enterprises in economically and politically stable environment, where little or no financial information is shared with foreign tax authorities. The aim of this research is to create a comprehensive overview of the characteristics and operations of tax havens, as well as to point out to the ways to overcome the problem of tax evasion. The methodology used in the work is characteristic of social science research: analysis, synthesis and discussion, comparative, inductive and historical analysis, together with the usage of relevant national and international sources. This paper describes the basic features of tax havens, as well as specific business models applied in them. A separate chapter deals with overcoming the problem of tax evasion, which is the main adverse effect of doing business through tax havens.

  19. Illusory motion reveals velocity matching, not foveation, drives smooth pursuit of large objects.

    Science.gov (United States)

    Ma, Zheng; Watamaniuk, Scott N J; Heinen, Stephen J

    2017-10-01

    When small objects move in a scene, we keep them foveated with smooth pursuit eye movements. Although large objects such as people and animals are common, it is nonetheless unknown how we pursue them since they cannot be foveated. It might be that the brain calculates an object's centroid, and then centers the eyes on it during pursuit as a foveation mechanism might. Alternatively, the brain merely matches the velocity by motion integration. We test these alternatives with an illusory motion stimulus that translates at a speed different from its retinal motion. The stimulus was a Gabor array that translated at a fixed velocity, with component Gabors that drifted with motion consistent or inconsistent with the translation. Velocity matching predicts different pursuit behaviors across drift conditions, while centroid matching predicts no difference. We also tested whether pursuit can segregate and ignore irrelevant local drifts when motion and centroid information are consistent by surrounding the Gabors with solid frames. Finally, observers judged the global translational speed of the Gabors to determine whether smooth pursuit and motion perception share mechanisms. We found that consistent Gabor motion enhanced pursuit gain while inconsistent, opposite motion diminished it, drawing the eyes away from the center of the stimulus and supporting a motion-based pursuit drive. Catch-up saccades tended to counter the position offset, directing the eyes opposite to the deviation caused by the pursuit gain change. Surrounding the Gabors with visible frames canceled both the gain increase and the compensatory saccades. Perceived speed was modulated analogous to pursuit gain. The results suggest that smooth pursuit of large stimuli depends on the magnitude of integrated retinal motion information, not its retinal location, and that the position system might be unnecessary for generating smooth velocity to large pursuit targets.

  20. Premotor neurons encode torsional eye velocity during smooth-pursuit eye movements

    Science.gov (United States)

    Angelaki, Dora E.; Dickman, J. David

    2003-01-01

    Responses to horizontal and vertical ocular pursuit and head and body rotation in multiple planes were recorded in eye movement-sensitive neurons in the rostral vestibular nuclei (VN) of two rhesus monkeys. When tested during pursuit through primary eye position, the majority of the cells preferred either horizontal or vertical target motion. During pursuit of targets that moved horizontally at different vertical eccentricities or vertically at different horizontal eccentricities, eye angular velocity has been shown to include a torsional component the amplitude of which is proportional to half the gaze angle ("half-angle rule" of Listing's law). Approximately half of the neurons, the majority of which were characterized as "vertical" during pursuit through primary position, exhibited significant changes in their response gain and/or phase as a function of gaze eccentricity during pursuit, as if they were also sensitive to torsional eye velocity. Multiple linear regression analysis revealed a significant contribution of torsional eye movement sensitivity to the responsiveness of the cells. These findings suggest that many VN neurons encode three-dimensional angular velocity, rather than the two-dimensional derivative of eye position, during smooth-pursuit eye movements. Although no clear clustering of pursuit preferred-direction vectors along the semicircular canal axes was observed, the sensitivity of VN neurons to torsional eye movements might reflect a preservation of similar premotor coding of visual and vestibular-driven slow eye movements for both lateral-eyed and foveate species.

  1. ACCOUNTING INFORMATION INDISPENSABLE SOURCE FOR THE DISCOVERY OF TAX EVASION IN THE FIELD OF PRODUCTS SUBJECT TO EXCISE

    Directory of Open Access Journals (Sweden)

    Dorel MATEȘ

    2015-12-01

    Full Text Available The present article aims to highlight the kinds of tax evasion methods in the field of products subject to excise duty and the role of the tax inspection in combating them. The research reveals which are the most common methods of tax evasion, but it tries to discern the probable developments of the process. The article has in view the inexorable reality, namely that the ingenuity method of tax fraud increases with the emergence of the new rules or barriers to the fraud. Following the research carried out we found that the tax evasion phenomenon in the field of products subject to excise duty has currently a significant impact in the economic and social Romanian reality. In order to reduce the tax evasion phenomenon in the field of products subject to excise duty, it must set up a mechanism for monitoring, oversight and fiscal control as well as the amendment of legislation, the tax evasion being mainly a consequence of the inaccuracies or imperfection of laws.

  2. Does the Sole Description of a Tax Authority Affect Tax Evasion? - The Impact of Described Coercive and Legitimate Power

    Science.gov (United States)

    Hartl, Barbara; Hofmann, Eva; Gangl, Katharina; Hartner-Tiefenthaler, Martina; Kirchler, Erich

    2015-01-01

    Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority’s power. Descriptions of the tax authority’s power may affect taxpayers’ beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority’s power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority’s power on participants’ beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants’ beliefs regarding tax authority’s power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority’s power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information. PMID:25923770

  3. THE VAT SPLIT-PAYMENT MECHANISM, MEASURE FOR COMBATING TAX EVASION IN ROMANIA

    Directory of Open Access Journals (Sweden)

    IONUT - GHEORGHE CARAUS

    2017-12-01

    Full Text Available The need to improve the methods of collecting and detecting value-added tax amounts is an increasingly difficult process for tax authorities. In this respect, a rigorous analysis of the ways in which the state manages to prevent or combat VAT evasion, in the context in which VAT fraud accounts for about 60% of Romania's total tax evasion, is required. Therefore, the new provisions concerning the VAT split payments, applicable from January 1, 2018 for all categories of taxpayers, can contribute significantly to the efficiency of collection, of the amounts derived from the VAT, as well as to reduce tax evasion in the field of value added tax and providing a fair competitive environment, by eliminating benefits for economic operators with incorrect tax behavior who do not pay VAT to the State budget. Also, through these measures taken by the state, the main motivation for the introduction of the value added tax splitpayments mechanism, contributes to the increase of the voluntary compliance degree by providing the financial resources for the payment of VAT due to the State budget.

  4. Complement and innate immune evasion strategies of the human pathogenic fungus Candida albicans.

    Science.gov (United States)

    Luo, Shanshan; Skerka, Christine; Kurzai, Oliver; Zipfel, Peter F

    2013-12-15

    Candida albicans is a medically important fungus that can cause a wide range of diseases ranging from superficial infections to disseminated disease, which manifests primarily in immuno-compromised individuals. Despite the currently applied anti-fungal therapies, both mortality and morbidity caused by this human pathogenic fungus are still unacceptably high. Therefore new prophylactic and therapeutic strategies are urgently needed to prevent fungal infection. In order to define new targets for combating fungal disease, there is a need to understand the immune evasion strategies of C. albicans in detail. In this review, we summarize different sophisticated immune evasion strategies that are utilized by C. albicans. The description of the molecular mechanisms used for immune evasion does on one hand help to understand the infection process, and on the other hand provides valuable information to define new strategies and diagnostic approaches to fight and interfere with Candida infections. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Immunological Evasion in Glioblastoma

    Directory of Open Access Journals (Sweden)

    Roxana Magaña-Maldonado

    2016-01-01

    Full Text Available Glioblastoma is the most aggressive tumor in Central Nervous System in adults. Among its features, modulation of immune system stands out. Although immune system is capable of detecting and eliminating tumor cells mainly by cytotoxic T and NK cells, tumor microenvironment suppresses an effective response through recruitment of modulator cells such as regulatory T cells, monocyte-derived suppressor cells, M2 macrophages, and microglia as well as secretion of immunomodulators including IL-6, IL-10, CSF-1, TGF-β, and CCL2. Other mechanisms that induce immunosuppression include enzymes as indolamine 2,3-dioxygenase. For this reason it is important to develop new therapies that avoid this immune evasion to promote an effective response against glioblastoma.

  6. Path Planning Algorithms for Autonomous Border Patrol Vehicles

    Science.gov (United States)

    Lau, George Tin Lam

    This thesis presents an online path planning algorithm developed for unmanned vehicles in charge of autonomous border patrol. In this Pursuit-Evasion game, the unmanned vehicle is required to capture multiple trespassers on its own before any of them reach a target safe house where they are safe from capture. The problem formulation is based on Isaacs' Target Guarding problem, but extended to the case of multiple evaders. The proposed path planning method is based on Rapidly-exploring random trees (RRT) and is capable of producing trajectories within several seconds to capture 2 or 3 evaders. Simulations are carried out to demonstrate that the resulting trajectories approach the optimal solution produced by a nonlinear programming-based numerical optimal control solver. Experiments are also conducted on unmanned ground vehicles to show the feasibility of implementing the proposed online path planning algorithm on physical applications.

  7. The Hamming distance in the minority game

    Science.gov (United States)

    D'hulst, R.; Rodgers, G. J.

    1999-08-01

    We investigate different versions of the minority game, a toy model for agents buying and selling a commodity. The Hamming distance between the strategies used by agents to make decisions is introduced as an analytical tool to determine several properties of these models. The success rate of the agents in an adaptive version of the game is compared with the rate from a stochastic version. It is shown numerically and analytically that the adaptive process is inefficient, increasing the success rate of the unused strategies while decreasing the success rate of the strategies used by the agents. The agents do not do as well as if they were forced to use only one strategy permanently. A version of the game in which the agents strategies evolve is also analysed using the notion of distance. The agents evolve into a state in which they are all using one strategy, which is again the state that yields the maximum success rate.

  8. Tax Evasion, Information Reporting, and the Regressive Bias Hypothesis

    DEFF Research Database (Denmark)

    Boserup, Simon Halphen; Pinje, Jori Veng

    A robust prediction from the tax evasion literature is that optimal auditing induces a regressive bias in effective tax rates compared to statutory rates. If correct, this will have important distributional consequences. Nevertheless, the regressive bias hypothesis has never been tested empirically...

  9. Dynamics of multiple-goal pursuit.

    Science.gov (United States)

    Louro, Maria J; Pieters, Rik; Zeelenberg, Marcel

    2007-08-01

    The authors propose and test a model of multiple-goal pursuit that specifies how individuals allocate effort among multiple goals over time. The model predicts that whether individuals decide to step up effort, coast, abandon the current goal, or switch to pursue another goal is determined jointly by the emotions that flow from prior goal progress and the proximity to future goal attainment, and proximally determined by changes in expectancies about goal attainment. Results from a longitudinal diary study and 2 experiments show that positive and negative goal-related emotions can have diametrically opposing effects on goal-directed behavior, depending on the individual's proximity to goal attainment. The findings resolve contrasting predictions about the influence of positive and negative emotions in volitional behavior, critically amend the goal gradient hypothesis, and provide new insights into the dynamics and determinants of multiple-goal pursuit.

  10. Role of retinal slip in the prediction of target motion during smooth and saccadic pursuit.

    Science.gov (United States)

    de Brouwer, S; Missal, M; Lefèvre, P

    2001-08-01

    Visual tracking of moving targets requires the combination of smooth pursuit eye movements with catch-up saccades. In primates, catch-up saccades usually take place only during pursuit initiation because pursuit gain is close to unity. This contrasts with the lower and more variable gain of smooth pursuit in cats, where smooth eye movements are intermingled with catch-up saccades during steady-state pursuit. In this paper, we studied in detail the role of retinal slip in the prediction of target motion during smooth and saccadic pursuit in the cat. We found that the typical pattern of pursuit in the cat was a combination of smooth eye movements with saccades. During smooth pursuit initiation, there was a correlation between peak eye acceleration and target velocity. During pursuit maintenance, eye velocity oscillated at approximately 3 Hz around a steady-state value. The average gain of smooth pursuit was approximately 0.5. Trained cats were able to continue pursuing in the absence of a visible target, suggesting a role of the prediction of future target motion in this species. The analysis of catch-up saccades showed that the smooth-pursuit motor command is added to the saccadic command during catch-up saccades and that both position error and retinal slip are taken into account in their programming. The influence of retinal slip on catch-up saccades showed that prediction about future target motion is used in the programming of catch-up saccades. Altogether, these results suggest that pursuit systems in primates and cats are qualitatively similar, with a lower average gain in the cat and that prediction affects both saccades and smooth eye movements during pursuit.

  11. Research on user behavior authentication model based on stochastic Petri nets

    Science.gov (United States)

    Zhang, Chengyuan; Xu, Haishui

    2017-08-01

    A behavioural authentication model based on stochastic Petri net is proposed to meet the randomness, uncertainty and concurrency characteristics of user behaviour. The use of random models in the location, changes, arc and logo to describe the characteristics of a variety of authentication and game relationships, so as to effectively implement the graphical user behaviour authentication model analysis method, according to the corresponding proof to verify the model is valuable.

  12. Stochasticity in economic losses increases the value of reputation in indirect reciprocity.

    Science.gov (United States)

    dos Santos, Miguel; Placì, Sarah; Wedekind, Claus

    2015-12-14

    Recent theory predicts harsh and stochastic conditions to generally promote the evolution of cooperation. Here, we test experimentally whether stochasticity in economic losses also affects the value of reputation in indirect reciprocity, a type of cooperation that is very typical for humans. We used a repeated helping game with observers. One subject (the "Unlucky") lost some money, another one (the "Passer-by") could reduce this loss by accepting a cost to herself, thereby building up a reputation that could be used by others in later interactions. The losses were either stable or stochastic, but the average loss over time and the average efficiency gains of helping were kept constant in both treatments. We found that players with a reputation of being generous were generally more likely to receive help by others, such that investing into a good reputation generated long-term benefits that compensated for the immediate costs of helping. Helping frequencies were similar in both treatments, but players with a reputation to be selfish lost more resources under stochastic conditions. Hence, returns on investment were steeper when losses varied than when they did not. We conclude that this type of stochasticity increases the value of reputation in indirect reciprocity.

  13. A Simulation-Based Dynamic Stochastic Route Choice Model for Evacuation

    Directory of Open Access Journals (Sweden)

    Xing Zhao

    2012-01-01

    Full Text Available This paper establishes a dynamic stochastic route choice model for evacuation to simulate the propagation process of traffic flow and estimate the stochastic route choice under evacuation situations. The model contains a lane-group-based cell transmission model (CTM which sets different traffic capacities for links with different turning movements to flow out in an evacuation situation, an actual impedance model which is to obtain the impedance of each route in time units at each time interval and a stochastic route choice model according to the probit-based stochastic user equilibrium. In this model, vehicles loading at each origin at each time interval are assumed to choose an evacuation route under determinate road network, signal design, and OD demand. As a case study, the proposed model is validated on the network nearby Nanjing Olympic Center after the opening ceremony of the 10th National Games of the People's Republic of China. The traffic volumes and clearing time at five exit points of the evacuation zone are calculated by the model to compare with survey data. The results show that this model can appropriately simulate the dynamic route choice and evolution process of the traffic flow on the network in an evacuation situation.

  14. Mean Field Games with a Dominating Player

    Energy Technology Data Exchange (ETDEWEB)

    Bensoussan, A., E-mail: axb046100@utdallas.edu [The University of Texas at Dallas, International Center for Decision and Risk Analysis, Jindal School of Management (United States); Chau, M. H. M., E-mail: michaelchaumanho@gmail.com; Yam, S. C. P., E-mail: scpyam@sta.cuhk.edu.hk [The Chinese University of Hong Kong, Department of Statistics (Hong Kong, People’s Republic of China) (China)

    2016-08-15

    In this article, we consider mean field games between a dominating player and a group of representative agents, each of which acts similarly and also interacts with each other through a mean field term being substantially influenced by the dominating player. We first provide the general theory and discuss the necessary condition for the optimal controls and equilibrium condition by adopting adjoint equation approach. We then present a special case in the context of linear-quadratic framework, in which a necessary and sufficient condition can be asserted by stochastic maximum principle; we finally establish the sufficient condition that guarantees the unique existence of the equilibrium control. The proof of the convergence result of finite player game to mean field counterpart is provided in Appendix.

  15. Social Stratification and Cooperative Behavior in Spatial Prisoners' Dilemma Games.

    Directory of Open Access Journals (Sweden)

    Peng Lu

    Full Text Available It has been a long-lasting pursuit to promote cooperation, and this study aims to promote cooperation via the combination of social stratification and the spatial prisoners' dilemma game. It is previously assumed that agents share the identical payoff matrix, but the stratification or diversity exists and exerts influences in real societies. Thus, two additional classes, elites and scoundrels, derive from and coexist with the existing class, commons. Three classes have different payoff matrices. We construct a model where agents play the prisoners' dilemma game with neighbors. It indicates that stratification and temptation jointly influence cooperation. Temptation permanently reduces cooperation; elites play a positive role in promoting cooperation while scoundrels undermine it. As the temptation getting larger and larger, elites play a more and more positive and critical role while scoundrels' negative effect becomes weaker and weaker, and it is more obvious when temptation goes beyond its threshold.

  16. Stochastic Averaging and Stochastic Extremum Seeking

    CERN Document Server

    Liu, Shu-Jun

    2012-01-01

    Stochastic Averaging and Stochastic Extremum Seeking develops methods of mathematical analysis inspired by the interest in reverse engineering  and analysis of bacterial  convergence by chemotaxis and to apply similar stochastic optimization techniques in other environments. The first half of the text presents significant advances in stochastic averaging theory, necessitated by the fact that existing theorems are restricted to systems with linear growth, globally exponentially stable average models, vanishing stochastic perturbations, and prevent analysis over infinite time horizon. The second half of the text introduces stochastic extremum seeking algorithms for model-free optimization of systems in real time using stochastic perturbations for estimation of their gradients. Both gradient- and Newton-based algorithms are presented, offering the user the choice between the simplicity of implementation (gradient) and the ability to achieve a known, arbitrary convergence rate (Newton). The design of algorithms...

  17. TAX EVASION, LEVEL OF INTERNET CORPORATE REPORTING AND FIRM VALUE: EVIDENCE FROM INDONESIAN MANUFACTURING FIRMS

    Directory of Open Access Journals (Sweden)

    Asmoro P.S.

    2018-03-01

    Full Text Available As a developing country that accumulates its source of revenue to taxes, Indonesia is not spared from tax compliance issues. The low level of tax compliance indicates a different point of view between the government and the Taxpayer. The low level of tax compliance indicates a different point of view between the government and the Taxpayer. Taxpayers still consider the obligation to pay taxes as an expense that can reduce their income or profits. Therefore, the rational Taxpayer will try to minimize the tax burden. One of them is by doing Tax Evasion. Taxation management is more often done by the Taxpayer Agency, especially the Manufacturing company. This is because the company has a very high business risk. Tax Evasion can increase organizational complexity which in turn can reduce financial transparency. Therefore, companies are required to disclose more information and provide flexible reporting systems that facilitate stakeholders. This encourages companies in the world to take advantage of the development of information technology and interconnection networking through internet corporate reporting. Utilization of internet corporate reporting is expected to increase the value of the company. This study aims to analyze the relationship between the concept of Tax Evasion, the level of internet corporate reporting disclosure, and the firm value. The results showed that the three hypotheses in this study were accepted. Tax Evasion affects the level of internet corporate reporting disclosure. In addition, Tax Evasion also directly or indirectly influence the firm value through the level disclosure of internet corporate reporting.

  18. Influence of positive subliminal and supraliminal affective cues on goal pursuit in schizophrenia

    NARCIS (Netherlands)

    Chaillou, Anne Clémence; Giersch, Anne; Bonnefond, Anne; Custers, Ruud; Capa, Rémi L.

    2015-01-01

    Goal pursuit is known to be impaired in schizophrenia, but nothing much is known in these patients about unconscious affective processes underlying goal pursuit. Evidence suggests that in healthy individuals positive subliminal cues are taken as a signal that goal pursuit is easy and therefore

  19. BSDES IN GAMES, COUPLED WITH THE VALUE FUNCTIONS.ASSOCIATED NONLOCAL BELLMAN-ISAACS EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Tao HAO; Juan LI

    2017-01-01

    We establish a new type of backward stochastic differential equations (BSDEs) connected with stochastic differential games (SDGs),namely,BSDEs strongly coupled with the lower and the upper value functions of SDGs,where the lower and the upper value functions are defined through this BSDE.The existence and the uniqueness theorem and comparison theorem are proved for such equations with the help of an iteration method.We also show that the lower and the upper value functions satisfy the dynamic programming principle.Moreover,we study the associated Hamilton-Jacobi-Bellman-Isaacs (HJB-Isaacs) equations,which are nonlocal,and strongly coupled with the lower and the upper value functions.Using a new method,we characterize the pair (W,U) consisting of the lower and the upper value functions as the unique viscosity solution of our nonlocal HJB-Isaacs equation.Furthermore,the game has a value under the Isaacs' condition.

  20. TAX EVASION BETWEEN FRAUD AND OPTIMIZATION

    OpenAIRE

    Emilia Cornelia STOICA

    2017-01-01

    Tax optimization, often called legal tax evasion is the use of methods and techniques that are within the law, in order to reduce or even cancel the tax liability. To achieve such an approach, the taxpayer or his advisers must know in depth the tax law - and by extension, the financial and administrative law - and, moreover, must be functional tax jurisdictions which allow the use of appropriate assemblies. The recent leasks, as WikiLeaks, LuxLeaks, SwissLeaks, Panama Papers etc. on financial...

  1. Immune Evasion Strategies and Persistence of Helicobacter pylori.

    Science.gov (United States)

    Mejías-Luque, Raquel; Gerhard, Markus

    Helicobacter pylori infection is commonly acquired during childhood, can persist lifelong if not treated, and can cause different gastric pathologies, including chronic gastritis, peptic ulcer disease, and eventually gastric cancer. H. pylori has developed a number of strategies in order to cope with the hostile conditions found in the human stomach as well as successful mechanisms to evade the strong innate and adaptive immune responses elicited upon infection. Thus, by manipulating innate immune receptors and related signaling pathways, inducing tolerogenic dendritic cells and inhibiting effector T cell responses, H. pylori ensures low recognition by the host immune system as well as its persistence in the gastric epithelium. Bacterial virulence factors such as cytotoxin-associated gene A, vacuolating cytotoxin A, or gamma-glutamyltranspeptidase have been extensively studied in the context of bacterial immune escape and persistence. Further, the bacterium possesses other factors that contribute to immune evasion. In this chapter, we discuss in detail the main evasion and persistence strategies evolved by the bacterium as well as the specific bacterial virulence factors involved.

  2. Immune evasion strategies of ranaviruses and innate immune responses to these emerging pathogens.

    Science.gov (United States)

    Grayfer, Leon; Andino, Francisco De Jesús; Chen, Guangchun; Chinchar, Gregory V; Robert, Jacques

    2012-07-01

    Ranaviruses (RV, Iridoviridae) are large double-stranded DNA viruses that infect fish, amphibians and reptiles. For ecological and commercial reasons, considerable attention has been drawn to the increasing prevalence of ranaviral infections of wild populations and in aquacultural settings. Importantly, RVs appear to be capable of crossing species barriers of numerous poikilotherms, suggesting that these pathogens possess a broad host range and potent immune evasion mechanisms. Indeed, while some of the 95-100 predicted ranavirus genes encode putative evasion proteins (e.g., vIFα, vCARD), roughly two-thirds of them do not share significant sequence identity with known viral or eukaryotic genes. Accordingly, the investigation of ranaviral virulence and immune evasion strategies is promising for elucidating potential antiviral targets. In this regard, recombination-based technologies are being employed to knock out gene candidates in the best-characterized RV member, Frog Virus (FV3). Concurrently, by using animal infection models with extensively characterized immune systems, such as the African clawed frog, Xenopus laevis, it is becoming evident that components of innate immunity are at the forefront of virus-host interactions. For example, cells of the macrophage lineage represent important combatants of RV infections while themselves serving as targets for viral infection, maintenance and possibly dissemination. This review focuses on the recent advances in the understanding of the RV immune evasion strategies with emphasis on the roles of the innate immune system in ranaviral infections.

  3. Receptive fields for smooth pursuit eye movements and motion perception.

    Science.gov (United States)

    Debono, Kurt; Schütz, Alexander C; Spering, Miriam; Gegenfurtner, Karl R

    2010-12-01

    Humans use smooth pursuit eye movements to track moving objects of interest. In order to track an object accurately, motion signals from the target have to be integrated and segmented from motion signals in the visual context. Most studies on pursuit eye movements used small visual targets against a featureless background, disregarding the requirements of our natural visual environment. Here, we tested the ability of the pursuit and the perceptual system to integrate motion signals across larger areas of the visual field. Stimuli were random-dot kinematograms containing a horizontal motion signal, which was perturbed by a spatially localized, peripheral motion signal. Perturbations appeared in a gaze-contingent coordinate system and had a different direction than the main motion including a vertical component. We measured pursuit and perceptual direction discrimination decisions and found that both steady-state pursuit and perception were influenced most by perturbation angles close to that of the main motion signal and only in regions close to the center of gaze. The narrow direction bandwidth (26 angular degrees full width at half height) and small spatial extent (8 degrees of visual angle standard deviation) correspond closely to tuning parameters of neurons in the middle temporal area (MT). Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway.

    Science.gov (United States)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine; Garred, Peter

    2017-01-01

    The complement system is a crucial defensive network that protects the host against invading pathogens. It is part of the innate immune system and can be initiated via three pathways: the lectin, classical and alternative activation pathway. Overall the network compiles a group of recognition molecules that bind specific patterns on microbial surfaces, a group of associated proteases that initiates the complement cascade, and a group of proteins that interact in proteolytic complexes or the terminal pore-forming complex. In addition, various regulatory proteins are important for controlling the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system. Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part of the cascade. This review will cover the currently known lectin pathway evasion mechanisms and give examples of pathogens that operate these to increase their chance of invasion, survival and dissemination.

  5. Shared sensory estimates for human motion perception and pursuit eye movements.

    Science.gov (United States)

    Mukherjee, Trishna; Battifarano, Matthew; Simoncini, Claudio; Osborne, Leslie C

    2015-06-03

    Are sensory estimates formed centrally in the brain and then shared between perceptual and motor pathways or is centrally represented sensory activity decoded independently to drive awareness and action? Questions about the brain's information flow pose a challenge because systems-level estimates of environmental signals are only accessible indirectly as behavior. Assessing whether sensory estimates are shared between perceptual and motor circuits requires comparing perceptual reports with motor behavior arising from the same sensory activity. Extrastriate visual cortex both mediates the perception of visual motion and provides the visual inputs for behaviors such as smooth pursuit eye movements. Pursuit has been a valuable testing ground for theories of sensory information processing because the neural circuits and physiological response properties of motion-responsive cortical areas are well studied, sensory estimates of visual motion signals are formed quickly, and the initiation of pursuit is closely coupled to sensory estimates of target motion. Here, we analyzed variability in visually driven smooth pursuit and perceptual reports of target direction and speed in human subjects while we manipulated the signal-to-noise level of motion estimates. Comparable levels of variability throughout viewing time and across conditions provide evidence for shared noise sources in the perception and action pathways arising from a common sensory estimate. We found that conditions that create poor, low-gain pursuit create a discrepancy between the precision of perception and that of pursuit. Differences in pursuit gain arising from differences in optic flow strength in the stimulus reconcile much of the controversy on this topic. Copyright © 2015 the authors 0270-6474/15/358515-16$15.00/0.

  6. Evasion of T cell immunity by Epstein-Barr virus

    NARCIS (Netherlands)

    Horst, D.

    2011-01-01

    Immune evasion strategies are thought to contribute essentially to the life cycle of persistent viruses by delaying the elimination of the infected cell long enough to enable the virus to replicate. Exemplary in this context are the herpesviruses, large DNA viruses that are carried as a persistent

  7. Tax evasion and income source: A comparative experimental study

    NARCIS (Netherlands)

    Gërxhani, K.; Schram, A.J.H.C.

    2006-01-01

    We compare tax evasive behavior in a country in transition from communism to that in a developed economy by running an experiment across distinct social groups in Albania and the Netherlands. Aside from the tax compliance decision, subjects choose a source of income, where one type enables

  8. On Social Optima of Non-Cooperative Mean Field Games

    Energy Technology Data Exchange (ETDEWEB)

    Li, Sen; Zhang, Wei; Zhao, Lin; Lian, Jianming; Kalsi, Karanjit

    2016-12-12

    This paper studies the social optima in noncooperative mean-field games for a large population of agents with heterogeneous stochastic dynamic systems. Each agent seeks to maximize an individual utility functional, and utility functionals of different agents are coupled through a mean field term that depends on the mean of the population states/controls. The paper has the following contributions. First, we derive a set of control strategies for the agents that possess *-Nash equilibrium property, and converge to the mean-field Nash equilibrium as the population size goes to infinity. Second, we study the social optimal in the mean field game. We derive the conditions, termed the socially optimal conditions, under which the *-Nash equilibrium of the mean field game maximizes the social welfare. Third, a primal-dual algorithm is proposed to compute the *-Nash equilibrium of the mean field game. Since the *-Nash equilibrium of the mean field game is socially optimal, we can compute the equilibrium by solving the social welfare maximization problem, which can be addressed by a decentralized primal-dual algorithm. Numerical simulations are presented to demonstrate the effectiveness of the proposed approach.

  9. Contextual effects on motion perception and smooth pursuit eye movements.

    Science.gov (United States)

    Spering, Miriam; Gegenfurtner, Karl R

    2008-08-15

    Smooth pursuit eye movements are continuous, slow rotations of the eyes that allow us to follow the motion of a visual object of interest. These movements are closely related to sensory inputs from the visual motion processing system. To track a moving object in the natural environment, its motion first has to be segregated from the motion signals provided by surrounding stimuli. Here, we review experiments on the effect of the visual context on motion processing with a focus on the relationship between motion perception and smooth pursuit eye movements. While perception and pursuit are closely linked, we show that they can behave quite distinctly when required by the visual context.

  10. Tumor immune evasion arises through loss of TNF sensitivity.

    Science.gov (United States)

    Kearney, Conor J; Vervoort, Stephin J; Hogg, Simon J; Ramsbottom, Kelly M; Freeman, Andrew J; Lalaoui, Najoua; Pijpers, Lizzy; Michie, Jessica; Brown, Kristin K; Knight, Deborah A; Sutton, Vivien; Beavis, Paul A; Voskoboinik, Ilia; Darcy, Phil K; Silke, John; Trapani, Joseph A; Johnstone, Ricky W; Oliaro, Jane

    2018-05-18

    Immunotherapy has revolutionized outcomes for cancer patients, but the mechanisms of resistance remain poorly defined. We used a series of whole-genome clustered regularly interspaced short palindromic repeat (CRISPR)-based screens performed in vitro and in vivo to identify mechanisms of tumor immune evasion from cytotoxic lymphocytes [CD8 + T cells and natural killer (NK) cells]. Deletion of key genes within the tumor necrosis factor (TNF) signaling, interferon-γ (IFN-γ) signaling, and antigen presentation pathways provided protection of tumor cells from CD8 + T cell-mediated killing and blunted antitumor immune responses in vivo. Deletion of a number of genes in the TNF pathway also emerged as the key mechanism of immune evasion from primary NK cells. Our screens also identified that the metabolic protein 2-aminoethanethiol dioxygenase (Ado) modulates sensitivity to TNF-mediated killing by cytotoxic lymphocytes and is required for optimal control of tumors in vivo. Remarkably, we found that tumors delete the same genes when exposed to perforin-deficient CD8 + T cells, demonstrating that the dominant immune evasion strategy used by tumor cells is acquired resistance to T cell-derived cytokine-mediated antitumor effects. We demonstrate that TNF-mediated bystander killing is a potent T cell effector mechanism capable of killing antigen-negative tumor cells. In addition to highlighting the importance of TNF in CD8 + T cell- and NK cell-mediated killing of tumor cells, our study also provides a comprehensive picture of the roles of the TNF, IFN, and antigen presentation pathways in immune-mediated tumor surveillance. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  11. Contrast and assimilation in motion perception and smooth pursuit eye movements.

    Science.gov (United States)

    Spering, Miriam; Gegenfurtner, Karl R

    2007-09-01

    The analysis of visual motion serves many different functions ranging from object motion perception to the control of self-motion. The perception of visual motion and the oculomotor tracking of a moving object are known to be closely related and are assumed to be controlled by shared brain areas. We compared perceived velocity and the velocity of smooth pursuit eye movements in human observers in a paradigm that required the segmentation of target object motion from context motion. In each trial, a pursuit target and a visual context were independently perturbed simultaneously to briefly increase or decrease in speed. Observers had to accurately track the target and estimate target speed during the perturbation interval. Here we show that the same motion signals are processed in fundamentally different ways for perception and steady-state smooth pursuit eye movements. For the computation of perceived velocity, motion of the context was subtracted from target motion (motion contrast), whereas pursuit velocity was determined by the motion average (motion assimilation). We conclude that the human motion system uses these computations to optimally accomplish different functions: image segmentation for object motion perception and velocity estimation for the control of smooth pursuit eye movements.

  12. Risk-sensitive control of stochastic hybrid systems on infinite time horizon

    Directory of Open Access Journals (Sweden)

    Runolfsson Thordur

    1999-01-01

    Full Text Available A risk-sensitive optimal control problem is considered for a hybrid system that consists of continuous time diffusion process that depends on a discrete valued mode variable that is modeled as a Markov chain. Optimality conditions are presented and conditions for the existence of optimal controls are derived. It is shown that the optimal risk-sensitive control problem is equivalent to the upper value of an associated stochastic differential game, and insight into the contributions of the noise input and mode variable to the risk sensitivity of the cost functional is given. Furthermore, it is shown that due to the mode variable risk sensitivity, the equivalence relationship that has been observed between risk-sensitive and H ∞ control in the nonhybrid case does not hold for stochastic hybrid systems.

  13. The Evasion of the Text; Invasion of the Text; Again, Evasion of the Text; "The Eagle and the Mole": The Affective Fallacy Revisited.

    Science.gov (United States)

    Ducharme, Edward R.; And Others

    1970-01-01

    Three writers debate whether English teachers should depend on external or internal criteria when analyzing and teaching literature. Each writer discusses the meaning of Elinor Wylie's poem, "The Eagle and the Mole," according to his particular view of literary analysis. Edward Ducharme, in "The Evasion of the Text," submits…

  14. Tax evasive behavior and gender in a transition count

    NARCIS (Netherlands)

    Gërxhani, K.; Kuiper, E.

    2004-01-01

    In this paper, we provide a structural explanation of gender difference with respect to tax evasion. A unique data set, collected from a field survey of households in Albania, allows us to test and explore the established fact, in a transition country. The results show that women tend to evade taxes

  15. A Markov game theoretic data fusion approach for cyber situational awareness

    Science.gov (United States)

    Shen, Dan; Chen, Genshe; Cruz, Jose B., Jr.; Haynes, Leonard; Kruger, Martin; Blasch, Erik

    2007-04-01

    This paper proposes an innovative data-fusion/ data-mining game theoretic situation awareness and impact assessment approach for cyber network defense. Alerts generated by Intrusion Detection Sensors (IDSs) or Intrusion Prevention Sensors (IPSs) are fed into the data refinement (Level 0) and object assessment (L1) data fusion components. High-level situation/threat assessment (L2/L3) data fusion based on Markov game model and Hierarchical Entity Aggregation (HEA) are proposed to refine the primitive prediction generated by adaptive feature/pattern recognition and capture new unknown features. A Markov (Stochastic) game method is used to estimate the belief of each possible cyber attack pattern. Game theory captures the nature of cyber conflicts: determination of the attacking-force strategies is tightly coupled to determination of the defense-force strategies and vice versa. Also, Markov game theory deals with uncertainty and incompleteness of available information. A software tool is developed to demonstrate the performance of the high level information fusion for cyber network defense situation and a simulation example shows the enhanced understating of cyber-network defense.

  16. Stochastic processes, optimization, and control theory a volume in honor of Suresh Sethi

    CERN Document Server

    Yan, Houmin

    2006-01-01

    This edited volume contains 16 research articles. It presents recent and pressing issues in stochastic processes, control theory, differential games, optimization, and their applications in finance, manufacturing, queueing networks, and climate control. One of the salient features is that the book is highly multi-disciplinary. The book is dedicated to Professor Suresh Sethi on the occasion of his 60th birthday, in view of his distinguished career.

  17. Psychological motives and online games addiction: a test of flow theory and humanistic needs theory for Taiwanese adolescents.

    Science.gov (United States)

    Wan, Chin-Sheng; Chiou, Wen-Bin

    2006-06-01

    Obviously, the negative impact of online games has received much attention as well as having become a popular research topic. This research explored, from flow theory and humanistic needs theory, the psychological motivations of Taiwanese adolescents who are addicted to online games. The purpose of Study 1 was to investigate the relationship between players' flow state and their online games addiction. The results indicated that flow state was negatively correlated with addictive inclination and it was not a significant predictor for players' subsequent additive inclination. Findings also revealed that the addicts' flow state was significantly lower than the nonaddicts. Thus, flow state might not be the key psychological mechanism of players' addiction. In Study 2, the results showed that the psychological needs of players of online games were close to the two-factor theory which depicts satisfaction and dissatisfaction dimensions. Addicted players' need-gratification was similar to the feature of dissatisfactory factor. That is, the absence of playing online games is more likely to generate sense of dissatisfaction; the addicts' compulsive use of online games seems to stem from the relief of dissatisfaction rather than the pursuit of satisfaction. In contrast, online games tend to provide the nonaddicts with a sense of satisfaction rather than a sense of dissatisfaction.

  18. From genes to games: cooperation and cyclic dominance in meiotic drive.

    Science.gov (United States)

    Traulsen, Arne; Reed, Floyd A

    2012-04-21

    Evolutionary change can be described on a genotypic level or a phenotypic level. Evolutionary game theory is typically thought of as a phenotypic approach, although it is frequently argued that it can also be used to describe population genetic evolution. Interpreting the interaction between alleles in a diploid genome as a two player game leads to interesting alternative perspectives on genetic evolution. Here we focus on the case of meiotic drive and illustrate how meiotic drive can be directly and precisely interpreted as a social dilemma, such as the prisoners dilemma or the snowdrift game, in which the drive allele takes more than its fair share. Resistance to meiotic drive can lead to the well understood cyclic dominance found in the rock-paper-scissors game. This perspective is well established for the replicator dynamics, but there is still considerable ground for mutual inspiration between the two fields. For example, evolutionary game theorists can benefit from considering the stochastic evolutionary dynamics arising from finite population size. Population geneticists can benefit from game theoretic tools and perspectives on genetic evolution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Immune evasion of Plasmodium falciparum by RIFIN via inhibitory receptors

    DEFF Research Database (Denmark)

    Saito, Fumiji; Hirayasu, Kouyuki; Satoh, Takeshi

    2017-01-01

    , but the immune regulatory mechanisms used by P. falciparum remain largely unknown. Here we show that P. falciparum uses immune inhibitory receptors to achieve immune evasion. RIFIN proteins are products of a polymorphic multigene family comprising approximately 150-200 genes per parasite genome...

  20. Tax evasion, human capital, and productivity-induced tax rate reduction

    Czech Academy of Sciences Publication Activity Database

    Gillman, M.; Kejak, Michal

    2014-01-01

    Roč. 8, č. 1 (2014), s. 42-79 ISSN 1932-8575 Grant - others:UK(CZ) UNCE 204005/2012 Institutional support: PRVOUK-P23 Keywords : tax evasion * human capital * tax rates and tables Subject RIV: AH - Economics Impact factor: 0.600, year: 2014

  1. CMV immune evasion and manipulation of the immune system with aging.

    Science.gov (United States)

    Jackson, Sarah E; Redeker, Anke; Arens, Ramon; van Baarle, Debbie; van den Berg, Sara P H; Benedict, Chris A; Čičin-Šain, Luka; Hill, Ann B; Wills, Mark R

    2017-06-01

    Human cytomegalovirus (HCMV) encodes numerous proteins and microRNAs that function to evade the immune response and allow the virus to replicate and disseminate in the face of a competent innate and acquired immune system. The establishment of a latent infection by CMV, which if completely quiescent at the level of viral gene expression would represent an ultimate in immune evasion strategies, is not sufficient for lifelong persistence and dissemination of the virus. CMV needs to reactivate and replicate in a lytic cycle of infection in order to disseminate further, which occurs in the face of a fully primed secondary immune response. Without reactivation, latency itself would be redundant for the virus. It is also becoming clear that latency is not a totally quiescent state, but is characterized by limited viral gene expression. Therefore, the virus also needs immune evasion strategies during latency. An effective immune response to CMV is required or viral replication will cause morbidity and ultimately mortality in the host. There is clearly a complex balance between virus immune evasion and host immune recognition over a lifetime. This poses the important question of whether long-term evasion or manipulation of the immune response driven by CMV is detrimental to health. In this meeting report, three groups used the murine model of CMV (MCMV) to examine if the contribution of the virus to immune senescence is set by the (i) initial viral inoculum, (ii) inflation of T cell responses, (iii) or the balance between functionally distinct effector CD4+ T cells. The work of other groups studying the CMV response in humans is discussed. Their work asks whether the ability to make immune responses to new antigens is compromised by (i) age and HCMV carriage, (ii) long-term exposure to HCMV giving rise to an overall immunosuppressive environment and increased levels of latent virus, or (iii) adapted virus mutants (used as potential vaccines) that have the capacity to

  2. A sampling-based approach to probabilistic pursuit evasion

    KAUST Repository

    Mahadevan, Aditya

    2012-05-01

    Probabilistic roadmaps (PRMs) are a sampling-based approach to motion-planning that encodes feasible paths through the environment using a graph created from a subset of valid positions. Prior research has shown that PRMs can be augmented with useful information to model interesting scenarios related to multi-agent interaction and coordination. © 2012 IEEE.

  3. A sampling-based approach to probabilistic pursuit evasion

    KAUST Repository

    Mahadevan, Aditya; Amato, Nancy M.

    2012-01-01

    Probabilistic roadmaps (PRMs) are a sampling-based approach to motion-planning that encodes feasible paths through the environment using a graph created from a subset of valid positions. Prior research has shown that PRMs can be augmented

  4. The genomic features of parasitism, Polyembryony and immune evasion in the endoparasitic wasp Macrocentrus cingulum.

    Science.gov (United States)

    Yin, Chuanlin; Li, Meizhen; Hu, Jian; Lang, Kun; Chen, Qiming; Liu, Jinding; Guo, Dianhao; He, Kang; Dong, Yipei; Luo, Jiapeng; Song, Zhenkun; Walters, James R; Zhang, Wenqing; Li, Fei; Chen, Xuexin

    2018-05-30

    Parasitoid wasps are well-known natural enemies of major agricultural pests and arthropod borne diseases. The parasitoid wasp Macrocentrus cingulum (Hymenoptera: Braconidae) has been widely used to control the notorious insect pests Ostrinia furnacalis (Asian Corn Borer) and O. nubilalis (European corn borer). One striking phenomenon exhibited by M. cingulum is polyembryony, the formation of multiple genetically identical offspring from a single zygote. Moreover, M. cingulum employs a passive parasitic strategy by preventing the host's immune system from recognizing the embryo as a foreign body. Thus, the embryos evade the host's immune system and are not encapsulated by host hemocytes. Unfortunately, the mechanism of both polyembryony and immune evasion remains largely unknown. We report the genome of the parasitoid wasp M. cingulum. Comparative genomics analysis of M. cingulum and other 11 insects were conducted, finding some gene families with apparent expansion or contraction which might be linked to the parasitic behaviors or polyembryony of M. cingulum. Moreover, we present the evidence that the microRNA miR-14b regulates the polyembryonic development of M. cingulum by targeting the c-Myc Promoter-binding Protein 1 (MBP-1), histone-lysine N-methyltransferase 2E (KMT2E) and segmentation protein Runt. In addition, Hemomucin, an O-glycosylated transmembrane protein, protects the endoparasitoid wasp larvae from being encapsulated by host hemocytes. Motif and domain analysis showed that only the hemomucin in two endoparasitoids, M. cingulum and Venturia canescens, possessing the ability of passive immune evasion has intact mucin domain and similar O-glycosylation patterns, indicating that the hemomucin is a key factor modulating the immune evasion. The microRNA miR-14b participates in the regulation of polyembryonic development, and the O-glycosylation of the mucin domain in the hemomucin confers the passive immune evasion in this wasp. These key findings provide

  5. Narcissism and the Strategic Pursuit of Short-Term Mating

    DEFF Research Database (Denmark)

    Schmitt, David P.; Alcalay, Lidia; Allik, Jüri

    2017-01-01

    Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the curr...... limitations of these cross-culturally universal findings and presents suggestions for future research into revealing the precise psychological features of narcissism that facilitate the strategic pursuit of short-term mating....

  6. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway

    DEFF Research Database (Denmark)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine

    2017-01-01

    The complement system is a crucial defensive network that protects the host against invading pathogens. It is part of the innate immune system and can be initiated via three pathways: the lectin, classical and alternative activation pathway. Overall the network compiles a group of recognition...... the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system....... Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part...

  7. Analysing and controlling the tax evasion dynamics via majority-vote model

    Energy Technology Data Exchange (ETDEWEB)

    Lima, F W S, E-mail: fwslima@gmail.co, E-mail: wel@ufpi.edu.b [Departamento de Fisica, Universidade Federal do PiauI, 64049-550, Teresina - PI (Brazil)

    2010-09-01

    Within the context of agent-based Monte-Carlo simulations, we study the well-known majority-vote model (MVM) with noise applied to tax evasion on simple square lattices, Voronoi-Delaunay random lattices, Barabasi-Albert networks, and Erdoes-Renyi random graphs. In the order to analyse and to control the fluctuations for tax evasion in the economics model proposed by Zaklan, MVM is applied in the neighborhood of the noise critical q{sub c} to evolve the Zaklan model. The Zaklan model had been studied recently using the equilibrium Ising model. Here we show that the Zaklan model is robust because this can be studied using equilibrium dynamics of Ising model also through the nonequilibrium MVM and on various topologies cited above giving the same behavior regardless of dynamic or topology used here.

  8. Analysing and controlling the tax evasion dynamics via majority-vote model

    International Nuclear Information System (INIS)

    Lima, F W S

    2010-01-01

    Within the context of agent-based Monte-Carlo simulations, we study the well-known majority-vote model (MVM) with noise applied to tax evasion on simple square lattices, Voronoi-Delaunay random lattices, Barabasi-Albert networks, and Erdoes-Renyi random graphs. In the order to analyse and to control the fluctuations for tax evasion in the economics model proposed by Zaklan, MVM is applied in the neighborhood of the noise critical q c to evolve the Zaklan model. The Zaklan model had been studied recently using the equilibrium Ising model. Here we show that the Zaklan model is robust because this can be studied using equilibrium dynamics of Ising model also through the nonequilibrium MVM and on various topologies cited above giving the same behavior regardless of dynamic or topology used here.

  9. L'evasione in Italia e nei paesi OCSE: evidenze empiriche, determinanti ed effetti economici (Evasion in Italy and in OECD countries: empirical evidence, determinants and economic effects

    Directory of Open Access Journals (Sweden)

    M. MARÈ

    2013-10-01

    Full Text Available The paper analyses evasion in terms of size and its main determinants, and discusses some of the measures to reduce its extension. Instead of attempting a new estimate of evasion, the author uses the many existing estimates and compares them, highlighting their strengths and weaknesses. The available data on the underground economy and fiscal evasion in Italy and in major OECD countries is shown. Then, after recalling its effects on public budgets, the other economic effects of evasion are discussed. Some determinants of tax evasion, in particular those that appear most significant for our country, are then analysed. Finally, major issues of economic policy and measures to reduce tax evasion are discussed.JEL: H26

  10. Tax evasion, human capital, and productivity-induced tax rate reduction

    Czech Academy of Sciences Publication Activity Database

    Gillman, Max; Kejak, Michal

    2014-01-01

    Roč. 8, č. 1 (2014), s. 42-79 ISSN 1932-8575 R&D Projects: GA ČR GA13-34096S Institutional support: RVO:67985998 Keywords : tax evasion * human capital * tax rates and tables Subject RIV: AH - Economics Impact factor: 0.600, year: 2014

  11. Complement Evasion by Pathogenic Leptospira.

    Science.gov (United States)

    Fraga, Tatiana Rodrigues; Isaac, Lourdes; Barbosa, Angela Silva

    2016-01-01

    Leptospirosis is a neglected infectious disease caused by spirochetes from the genus Leptospira . Pathogenic microorganisms, notably those which reach the blood circulation such as Leptospira , have evolved multiple strategies to escape the host complement system, which is important for innate and acquired immunity. Leptospira avoid complement-mediated killing through: (i) recruitment of host complement regulators; (ii) acquisition of host proteases that cleave complement proteins on the bacterial surface; and, (iii) secretion of proteases that inactivate complement proteins in the Leptospira surroundings. The recruitment of host soluble complement regulatory proteins includes the acquisition of Factor H (FH) and FH-like-1 (alternative pathway), C4b-binding protein (C4BP) (classical and lectin pathways), and vitronectin (Vn) (terminal pathway). Once bound to the leptospiral surface, FH and C4BP retain cofactor activity of Factor I in the cleavage of C3b and C4b, respectively. Vn acquisition by leptospires may result in terminal pathway inhibition by blocking C9 polymerization. The second evasion mechanism lies in plasminogen (PLG) binding to the leptospiral surface. In the presence of host activators, PLG is converted to enzymatically active plasmin, which is able to degrade C3b, C4b, and C5 at the surface of the pathogen. A third strategy used by leptospires to escape from complement system is the active secretion of proteases. Pathogenic, but not saprophytic leptospires, are able to secrete metalloproteases that cleave C3 (central complement molecule), Factor B (alternative pathway), and C4 and C2 (classical and lectin pathways). The purpose of this review is to fully explore these complement evasion mechanisms, which act together to favor Leptospira survival and multiplication in the host.

  12. Coordinated Control of Three-Dimensional Components of Smooth Pursuit to Rotating and Translating Textures.

    Science.gov (United States)

    Edinger, Janick; Pai, Dinesh K; Spering, Miriam

    2017-01-01

    The neural control of pursuit eye movements to visual textures that simultaneously translate and rotate has largely been neglected. Here we propose that pursuit of such targets-texture pursuit-is a fully three-dimensional task that utilizes all three degrees of freedom of the eye, including torsion. Head-fixed healthy human adults (n = 8) tracked a translating and rotating random dot pattern, shown on a computer monitor, with their eyes. Horizontal, vertical, and torsional eye positions were recorded with a head-mounted eye tracker. The torsional component of pursuit is a function of the rotation of the texture, aligned with its visual properties. We observed distinct behaviors between those trials in which stimulus rotation was in the same direction as that of a rolling ball ("natural") in comparison to those with the opposite rotation ("unnatural"): Natural rotation enhanced and unnatural rotation reversed torsional velocity during pursuit, as compared to torsion triggered by a nonrotating random dot pattern. Natural rotation also triggered pursuit with a higher horizontal velocity gain and fewer and smaller corrective saccades. Furthermore, we show that horizontal corrective saccades are synchronized with torsional corrective saccades, indicating temporal coupling of horizontal and torsional saccade control. Pursuit eye movements have a torsional component that depends on the visual stimulus. Horizontal and torsional eye movements are separated in the motor periphery. Our findings suggest that translational and rotational motion signals might be coordinated in descending pursuit pathways.

  13. Supply Chain-based Solution to Prevent Fuel Tax Evasion

    Energy Technology Data Exchange (ETDEWEB)

    Franzese, Oscar [ORNL; Capps, Gary J [ORNL; Daugherty, Michael [United States Department of Transportation (USDOT), Federal Highway Administration (FHWA); Siekmann, Adam [ORNL; Lascurain, Mary Beth [ORNL; Barker, Alan M [ORNL

    2016-01-01

    The primary source of funding for the United States transportation system is derived from motor fuel and other highway use taxes. Loss of revenue attributed to fuel-tax evasion has been assessed to be somewhere between $1 billion per year, or approximately 25% of the total tax collected. Any solution that addresses this problem needs to include not only the tax-collection agencies and auditors, but also the carriers transporting oil products and the carriers customers. This paper presents a system developed by the Oak Ridge National Laboratory for the Federal Highway Administration which has the potential to reduce or eliminate many fuel-tax evasion schemes. The solution balances the needs of tax-auditors and those of the fuel-hauling companies and their customers. The technology was deployed and successfully tested during an eight-month period on a real-world fuel-hauling fleet. Day-to-day operations of the fleet were minimally affected by their interaction with this system. The results of that test are discussed in this paper.

  14. Competition between color and luminance for target selection in smooth pursuit and saccadic eye movements.

    Science.gov (United States)

    Spering, Miriam; Montagnini, Anna; Gegenfurtner, Karl R

    2008-11-24

    Visual processing of color and luminance for smooth pursuit and saccadic eye movements was investigated using a target selection paradigm. In two experiments, stimuli were varied along the dimensions color and luminance, and selection of the more salient target was compared in pursuit and saccades. Initial pursuit was biased in the direction of the luminance component whereas saccades showed a relative preference for color. An early pursuit response toward luminance was often reversed to color by a later saccade. Observers' perceptual judgments of stimulus salience, obtained in two control experiments, were clearly biased toward luminance. This choice bias in perceptual data implies that the initial short-latency pursuit response agrees with perceptual judgments. In contrast, saccades, which have a longer latency than pursuit, do not seem to follow the perceptual judgment of salience but instead show a stronger relative preference for color. These substantial differences in target selection imply that target selection processes for pursuit and saccadic eye movements use distinctly different weights for color and luminance stimuli.

  15. Tax Havens: International Tax Avoidance and Evasion

    OpenAIRE

    Gravelle, Jane G.

    2009-01-01

    The federal government loses both individual and corporate income tax revenue from the shifting of profits and income into low-tax countries, often referred to as tax havens. Tax havens are located around the world with concentrations in the Caribbean and Europe. Corporate profit shifting may cost up to $60 billion in revenue and remedies are likely to involve tax law changes. Individual income tax losses more often arise from tax evasion, and are facilitated by the lack of information report...

  16. A Game-Theoretic Response Strategy for Coordinator Attack in Wireless Sensor Networks

    Science.gov (United States)

    Liu, Jianhua; Yue, Guangxue; Shang, Huiliang; Li, Hongjie

    2014-01-01

    The coordinator is a specific node that controls the whole network and has a significant impact on the performance in cooperative multihop ZigBee wireless sensor networks (ZWSNs). However, the malicious node attacks coordinator nodes in an effort to waste the resources and disrupt the operation of the network. Attacking leads to a failure of one round of communication between the source nodes and destination nodes. Coordinator selection is a technique that can considerably defend against attack and reduce the data delivery delay, and increase network performance of cooperative communications. In this paper, we propose an adaptive coordinator selection algorithm using game and fuzzy logic aiming at both minimizing the average number of hops and maximizing network lifetime. The proposed game model consists of two interrelated formulations: a stochastic game for dynamic defense and a best response policy using evolutionary game formulation for coordinator selection. The stable equilibrium best policy to response defense is obtained from this game model. It is shown that the proposed scheme can improve reliability and save energy during the network lifetime with respect to security. PMID:25105171

  17. Fixation of strategies with the Moran and Fermi processes in evolutionary games

    Science.gov (United States)

    Liu, Xuesong; He, Mingfeng; Kang, Yibin; Pan, Qiuhui

    2017-10-01

    A model of stochastic evolutionary game dynamics with finite population was built. It combines the standard Moran and Fermi rules with two strategies cooperation and defection. We obtain the expressions of fixation probabilities and fixation times. The one-third rule which has been found in the frequency dependent Moran process also holds for our model. We obtain the conditions of strategy being an evolutionarily stable strategy in our model, and then make a comparison with the standard Moran process. Besides, the analytical results show that compared with the standard Moran process, fixation occurs with higher probabilities under a prisoner's dilemma game and coordination game, but with lower probabilities under a coexistence game. The simulation result shows that the fixation time in our mixed process is lower than that in the standard Fermi process. In comparison with the standard Moran process, fixation always takes more time on average in spatial populations, regardless of the game. In addition, the fixation time decreases with the growth of the number of neighbors.

  18. Signaling pathways and immune evasion mechanisms in classical Hodgkin lymphoma.

    Science.gov (United States)

    Liu, W Robert; Shipp, Margaret A

    2017-11-23

    Classical Hodgkin lymphoma (cHL) is an unusual B-cell-derived malignancy in which rare malignant Hodgkin and Reed-Sternberg (HRS) cells are surrounded by an extensive but ineffective inflammatory/immune cell infiltrate. This striking feature suggests that malignant HRS cells escape immunosurveillance and interact with immune cells in the cancer microenvironment for survival and growth. We previously found that cHLs have a genetic basis for immune evasion: near-uniform copy number alterations of chromosome 9p24.1 and the associated PD-1 ligand loci, CD274/PD-L1 and PDCD1LG2/PD-L2, and copy number-dependent increased expression of these ligands. HRS cells expressing PD-1 ligands are thought to engage PD-1 receptor-positive immune effectors in the tumor microenvironment and induce PD-1 signaling and associated immune evasion. The genetic bases of enhanced PD-1 signaling in cHL make these tumors uniquely sensitive to PD-1 blockade. © 2017 by The American Society of Hematology.

  19. Automatic Epileptic Seizure Onset Detection Using Matching Pursuit

    DEFF Research Database (Denmark)

    Sorensen, Thomas Lynggaard; Olsen, Ulrich L.; Conradsen, Isa

    2010-01-01

    . The combination of Matching Pursuit and SVM for automatic seizure detection has never been tested before, making this a pilot study. Data from red different patients with 6 to 49 seizures are used to test our model. Three patients are recorded with scalp electroencephalography (sEEG) and three with intracranial...... electroencephalography (iEEG). A sensitivity of 78-100% and a detection latency of 5-18s has been achieved, while holding the false detection at 0.16-5.31/h. Our results show the potential of Matching Pursuit as a feature xtractor for detection of epileptic seizures....

  20. Pursuit Latency for Chromatic Targets

    Science.gov (United States)

    Mulligan, Jeffrey B.; Ellis, Stephen R. (Technical Monitor)

    1998-01-01

    The temporal dynamics of eye movement response to a change in direction of stimulus motion has been used to compare the processing speeds of different types of stimuli (Mulligan, ARVO '97). In this study, the pursuit response to colored targets was measured to test the hypothesis that the slow response of the chromatic system (as measured using traditional temporal sensitivity measures such as contrast sensitivity) results in increased eye movement latencies. Subjects viewed a small (0.4 deg) Gaussian spot which moved downward at a speed of 6.6 deg/sec. At a variable time during the trajectory, the dot's direction of motion changed by 30 degrees, either to the right or left. Subjects were instructed to pursue the spot. Eye movements were measured using a video ophthalmoscope with an angular resolution of approximately 1 arc min and a temporal sampling rate of 60 Hz. Stimuli were modulated in chrominance for a variety of hue directions, combined with a range of small luminance increments and decrements, to insure that some of the stimuli fell in the subjects' equiluminance planes. The smooth portions of the resulting eye movement traces were fit by convolving the stimulus velocity with an exponential having variable onset latency, time constant and amplitude. Smooth eye movements with few saccades were observed for all stimuli. Pursuit responses to stimuli having a significant luminance component are well-fit by exponentials having latencies and time constants on the order of 100 msec. Increases in pursuit response latency on the order of 100-200 msec are observed in response to certain stimuli, which occur in pairs of complementary hues, corresponding to the intersection of the stimulus section with the subjects' equiluminant plane. Smooth eye movements can be made in response to purely chromatic stimuli, but are slower than responses to stimuli with a luminance component.

  1. Mean field games for cognitive radio networks

    KAUST Repository

    Tembine, Hamidou

    2012-06-01

    In this paper we study mobility effect and power saving in cognitive radio networks using mean field games. We consider two types of users: primary and secondary users. When active, each secondary transmitter-receiver uses carrier sensing and is subject to long-term energy constraint. We formulate the interaction between primary user and large number of secondary users as an hierarchical mean field game. In contrast to the classical large-scale approaches based on stochastic geometry, percolation theory and large random matrices, the proposed mean field framework allows one to describe the evolution of the density distribution and the associated performance metrics using coupled partial differential equations. We provide explicit formulas and algorithmic power management for both primary and secondary users. A complete characterization of the optimal distribution of energy and probability of success is given.

  2. PREVENTION AND CONTROL OF THE TAX EVASION IMPACT ON ROMANIAN ECONOMY

    Directory of Open Access Journals (Sweden)

    Raluca Andreea TRANDAFIR

    2015-04-01

    Full Text Available Time of occurrence of tax evasion is closely linked even to social developments, this social phenomenon has emerged and evolved at the same time with the company. Since tax evasion is a phenomenon particularly harmful and despicable paradoxically, it has unfortunately been a negative and unintended consequence, with directions of development and different incidents in any country, regardless of size, level of development or form power organization. In Romania, the underground economy is strong because it is determined by the size of the phenomenon of crime in the economic and financial (dirty money, a phenomenon characterized by a very high level of "financial engineering" made in the privatization, investment, financial institutions - banks and the use of public funds. Thus, effective tools are triggered by conversion and diversion of capital flows in order to remove it from licit financial circuit.

  3. Predicting 2D target velocity cannot help 2D motion integration for smooth pursuit initiation.

    Science.gov (United States)

    Montagnini, Anna; Spering, Miriam; Masson, Guillaume S

    2006-12-01

    Smooth pursuit eye movements reflect the temporal dynamics of bidimensional (2D) visual motion integration. When tracking a single, tilted line, initial pursuit direction is biased toward unidimensional (1D) edge motion signals, which are orthogonal to the line orientation. Over 200 ms, tracking direction is slowly corrected to finally match the 2D object motion during steady-state pursuit. We now show that repetition of line orientation and/or motion direction does not eliminate the transient tracking direction error nor change the time course of pursuit correction. Nonetheless, multiple successive presentations of a single orientation/direction condition elicit robust anticipatory pursuit eye movements that always go in the 2D object motion direction not the 1D edge motion direction. These results demonstrate that predictive signals about target motion cannot be used for an efficient integration of ambiguous velocity signals at pursuit initiation.

  4. Mean-Field-Game Model for Botnet Defense in Cyber-Security

    Energy Technology Data Exchange (ETDEWEB)

    Kolokoltsov, V. N., E-mail: v.kolokoltsov@warwick.ac.uk [University of Warwick, Department of Statistics (United Kingdom); Bensoussan, A. [The University of Texas at Dallas, School of Management (United States)

    2016-12-15

    We initiate the analysis of the response of computer owners to various offers of defence systems against a cyber-hacker (for instance, a botnet attack), as a stochastic game of a large number of interacting agents. We introduce a simple mean-field game that models their behavior. It takes into account both the random process of the propagation of the infection (controlled by the botner herder) and the decision making process of customers. Its stationary version turns out to be exactly solvable (but not at all trivial) under an additional natural assumption that the execution time of the decisions of the customers (say, switch on or out the defence system) is much faster that the infection rates.

  5. Mean-Field-Game Model for Botnet Defense in Cyber-Security

    International Nuclear Information System (INIS)

    Kolokoltsov, V. N.; Bensoussan, A.

    2016-01-01

    We initiate the analysis of the response of computer owners to various offers of defence systems against a cyber-hacker (for instance, a botnet attack), as a stochastic game of a large number of interacting agents. We introduce a simple mean-field game that models their behavior. It takes into account both the random process of the propagation of the infection (controlled by the botner herder) and the decision making process of customers. Its stationary version turns out to be exactly solvable (but not at all trivial) under an additional natural assumption that the execution time of the decisions of the customers (say, switch on or out the defence system) is much faster that the infection rates.

  6. Diversity of scales makes an advantage: The case of the Minority Game

    Czech Academy of Sciences Publication Activity Database

    Pištěk, Miroslav; Slanina, František

    2011-01-01

    Roč. 390, č. 13 (2011), s. 2549-2561 ISSN 0378-4371 R&D Projects: GA ČR GA102/08/0567; GA MŠk OC09078 Institutional research plan: CEZ:AV0Z10750506; CEZ:AV0Z10100520 Keywords : Minority Game * Econophysics * Stochastic processes Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.373, year: 2011

  7. Effects of conformism on the cultural evolution of social behaviour.

    Directory of Open Access Journals (Sweden)

    Lucas Molleman

    Full Text Available Models of cultural evolution study how the distribution of cultural traits changes over time. The dynamics of cultural evolution strongly depends on the way these traits are transmitted between individuals by social learning. Two prominent forms of social learning are payoff-based learning (imitating others that have higher payoffs and conformist learning (imitating locally common behaviours. How payoff-based and conformist learning affect the cultural evolution of cooperation is currently a matter of lively debate, but few studies systematically analyse the interplay of these forms of social learning. Here we perform such a study by investigating how the interaction of payoff-based and conformist learning affects the outcome of cultural evolution in three social contexts. First, we develop a simple argument that provides insights into how the outcome of cultural evolution will change when more and more conformist learning is added to payoff-based learning. In a social dilemma (e.g. a Prisoner's Dilemma, conformism can turn cooperation into a stable equilibrium; in an evasion game (e.g. a Hawk-Dove game or a Snowdrift game conformism tends to destabilize the polymorphic equilibrium; and in a coordination game (e.g. a Stag Hunt game, conformism changes the basin of attraction of the two equilibria. Second, we analyse a stochastic event-based model, revealing that conformism increases the speed of cultural evolution towards pure equilibria. Individual-based simulations as well as the analysis of the diffusion approximation of the stochastic model by and large confirm our findings. Third, we investigate the effect of an increasing degree of conformism on cultural group selection in a group-structured population. We conclude that, in contrast to statements in the literature, conformism hinders rather than promotes the evolution of cooperation.

  8. Effects of conformism on the cultural evolution of social behaviour.

    Science.gov (United States)

    Molleman, Lucas; Pen, Ido; Weissing, Franz J

    2013-01-01

    Models of cultural evolution study how the distribution of cultural traits changes over time. The dynamics of cultural evolution strongly depends on the way these traits are transmitted between individuals by social learning. Two prominent forms of social learning are payoff-based learning (imitating others that have higher payoffs) and conformist learning (imitating locally common behaviours). How payoff-based and conformist learning affect the cultural evolution of cooperation is currently a matter of lively debate, but few studies systematically analyse the interplay of these forms of social learning. Here we perform such a study by investigating how the interaction of payoff-based and conformist learning affects the outcome of cultural evolution in three social contexts. First, we develop a simple argument that provides insights into how the outcome of cultural evolution will change when more and more conformist learning is added to payoff-based learning. In a social dilemma (e.g. a Prisoner's Dilemma), conformism can turn cooperation into a stable equilibrium; in an evasion game (e.g. a Hawk-Dove game or a Snowdrift game) conformism tends to destabilize the polymorphic equilibrium; and in a coordination game (e.g. a Stag Hunt game), conformism changes the basin of attraction of the two equilibria. Second, we analyse a stochastic event-based model, revealing that conformism increases the speed of cultural evolution towards pure equilibria. Individual-based simulations as well as the analysis of the diffusion approximation of the stochastic model by and large confirm our findings. Third, we investigate the effect of an increasing degree of conformism on cultural group selection in a group-structured population. We conclude that, in contrast to statements in the literature, conformism hinders rather than promotes the evolution of cooperation.

  9. Complement Attack against Aspergillus and Corresponding Evasion Mechanisms

    Directory of Open Access Journals (Sweden)

    Cornelia Speth

    2012-01-01

    Full Text Available Invasive aspergillosis shows a high mortality rate particularly in immunocompromised patients. Perpetually increasing numbers of affected patients highlight the importance of a clearer understanding of interactions between innate immunity and fungi. Innate immunity is considered to be the most significant host defence against invasive fungal infections. Complement represents a crucial part of this first line defence and comprises direct effects against invading pathogens as well as bridging functions to other parts of the immune network. However, despite the potency of complement to attack foreign pathogens, the prevalence of invasive fungal infections is increasing. Two possible reasons may explain that phenomenon: First, complement activation might be insufficient for an effective antifungal defence in risk patients (due to, e.g., low complement levels, poor recognition of fungal surface, or missing interplay with other immune elements in immunocompromised patients. On the other hand, fungi may have developed evasion strategies to avoid recognition and/or eradication by complement. In this review, we summarize the most important interactions between Aspergillus and the complement system. We describe the various ways of complement activation by Aspergillus and the antifungal effects of the system, and also show proven and probable mechanisms of Aspergillus for complement evasion.

  10. Inflammation promotes oral squamous carcinoma immune evasion via induced programmed death ligand-1 surface expression.

    Science.gov (United States)

    Lu, Wanlu; Lu, Libing; Feng, Yun; Chen, Jiao; Li, Yan; Kong, Xiangli; Chen, Sixiu; Li, Xiaoyu; Chen, Qianming; Zhang, Ping

    2013-05-01

    The association between inflammation and cancer provides a new target for tumor biotherapy. The inflammatory cells and molecules within the tumor microenvironment have decisive dual roles in antitumor immunity and immune evasion. In the present study, phytohemagglutinin (PHA) was used to stimulate peripheral blood mononuclear cells (PBMCs) to simulate the tumor inflammatory microenvironment. The effect of immune cells and inflammatory cytokines on the surface expression of programmed cell death-1 ligand 1 (PD-L1) and tumor immune evasion was investigated using flow cytometry (FCM) and an in vivo xenotransplantation model. Based on the data, PHA-activated, but not resting, immune cells were able to promote the surface expression of PD-L1 in Tca8113 oral squamous carcinoma cells via the secretion of inflammatory cytokines, but not by cell-cell contact. The majority of the inflammatory cytokines had no significant effect on the proliferation, cell cycle progression and apoptosis of the Tca8113 cells, although they each induced the expression of PD-L1 in a dose-dependent manner. In total, 99% of the Tca8113 cells expressed PD-L1 following treatment with the supernatant of PHA-stimulated PBMCs. The PHA-supernatant pretreated Tca8113 cells unusually induced Tca8113 antigen-specific CD8 + T cell apoptosis in vitro and the evasion of antigen-specific T cell attraction in a nude mouse tumor-bearing model. These results indicate a new mechanism for the promotion of tumor immune evasion by the tumor inflammatory microenvironment.

  11. Research on multirobot pursuit task allocation algorithm based on emotional cooperation factor.

    Science.gov (United States)

    Fang, Baofu; Chen, Lu; Wang, Hao; Dai, Shuanglu; Zhong, Qiubo

    2014-01-01

    Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots' individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm.

  12. Population Dynamics for Renewables in Electricity Markets: A Minority Game View

    DEFF Research Database (Denmark)

    Papakonstantinou, Athanasios; Pinson, Pierre

    2016-01-01

    The dominance of fluctuating and intermittent stochastic renewable energy sources (RES) has introduced uncertainty in power systems which in turn, has challenged how electricity market operate. In this context, there has been significant research in developing strategies for RES producers, which...... however typically focuses on the decision process of a single producer, assuming unrealistic access to aspects of information about the power system. This paper analyzes the behavior of an entire population of stochastic producers in an electricity market using as basis a minority game: the El Farol Bar...... problem. We illustrate how uncomplicated strategies based on a adaptive learning rules lead to the coordination among RES producers and a Pareto efficient outcome....

  13. Tax Evasion and Auditing in a Federal Economy

    OpenAIRE

    Traxler, Christian (Prof. Dr.); Stöwhase, Sven

    2017-01-01

    This paper analyzes the relation between tax auditing and fiscal equalization in the context of fiscal competition. We incorporate a model of tax evasion by firms into a standard tax competition framework where regional governments use their audit rates as a strategic instrument to engage in fiscal competition. We compare the region's choice of audit policies for three different cases: A scenario of unconfined competition without interregional transfers, a scenario with a gross revenue equali...

  14. Does Tax Evasion Affect Unemployment and Educational Choice ?

    DEFF Research Database (Denmark)

    Kolm, Ann-Sofie; Larsen, Birthe

    2003-01-01

    While examining the macroeconomic effects of government taxand punishment policies, this paper develops a three-sector generalequilibrium model featuring matching frictions and worker-firm wagebargaining. Workers are assumed to differ in ability, and the choiceof education is determined endogenou...... to choose punishment rates so to more than fully counteractthe distortion created by the government's inability to tax theinformal sector.JEL-codes: H26, I21, J64Keywords: Tax evasion, underground economy, education, matching,unemployment....

  15. On Concurrent Solutions in Differential Games

    Directory of Open Access Journals (Sweden)

    Romar Correa

    2011-01-01

    Full Text Available We examine solutions in which neither player is worse off from the leadership of one in a policy maker-public game. The loop model of dynamic games is used. Outcome space is dotted with equivalence classes of solutions. The Dynamic Stochastic General Equilibrium (DSGE results and their New Keynesian variants might represent one category. The economy is the neighborhood of a market-clearing equilibrium with Pareto-optimal properties modulo frictions. Our interest lies in the ‘old’ Keynesian genus where the representative state is one of involuntary unemployment. Two information sets are relevant. In the first case, agents look to the past and the present. In the second, they are bound by the information provided in the present. The standard analysis pertains to DSGE models under full information. We show, in contrast, that in a situation of structural disequilibrium and feedback information, all parties are better off reneging on the social compact to achieve a superior class of solutions.

  16. Immune Evasion Strategies of Pathogens in Macrophages: the Potential for Limiting Pathogen Transmission.

    Science.gov (United States)

    Ren, Yuwei; Khan, Faheem Ahmed; Pandupuspitasari, Nuruliarizki Shinta; Zhang, Shujun

    2017-01-01

    Preventing pathogen transmission to a new host is of major interest to the immunologist and could benefit from a detailed investigation of pathogen immune evasion strategies. The first line of defense against pathogen invasion is provided by macrophages. When they sense pathogens, macrophages initiate signals to inflammatory and pro-inflammatory cytokines through pattern recognition receptors (PRRs) subsequently mediating phagocytosis and inflammation. The macrophage immune machinery classically includes two subsets: the activated M1 and the activated M2 that respond accordingly in diverse immune challenges. The lipid and glycogen metabolic pathways work together with the lysosome to help the mature phagosome to degrade and eliminate intracellular pathogens in macrophages. The viral evasion strategies are even more complex due to the interplay between autophagy and apoptosis. However, pathogens evolve several strategies to camouflage themselves against immune responses in order to ensure their survival, replication and transmission. These strategies include the muting of PRRs initiated inflammatory responses, attenuation of M1 and/or induction of M2 macrophages, suppression of autophago-lysosomal formation, interference with lipid and glycogen metabolism, and viral mediation of autophagy and apoptosis cross-talk to enhance viral replication. This review focuses on pathogen immune evasion methods and on the strategies used by the host against camouflaged pathogens.

  17. Immune evasion mechanisms and immune checkpoint inhibition in advanced merkel cell carcinoma.

    Science.gov (United States)

    Schadendorf, Dirk; Nghiem, Paul; Bhatia, Shailender; Hauschild, Axel; Saiag, Philippe; Mahnke, Lisa; Hariharan, Subramanian; Kaufman, Howard L

    2017-01-01

    Merkel cell carcinoma (MCC) is a rare skin cancer caused by Merkel cell polyomavirus (MCPyV) infection and/or ultraviolet radiation-induced somatic mutations. The presence of tumor-infiltrating lymphocytes is evidence that an active immune response to MCPyV and tumor-associated neoantigens occurs in some patients. However, inhibitory immune molecules, including programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1), within the MCC tumor microenvironment aid in tumor evasion of T-cell-mediated clearance. Unlike chemotherapy, treatment with anti-PD-L1 (avelumab) or anti-PD-1 (pembrolizumab) antibodies leads to durable responses in MCC, in both virus-positive and virus-negative tumors. As many tumors are established through the evasion of infiltrating immune-cell clearance, the lessons learned in MCC may be broadly relevant to many cancers.

  18. Social Dimensions of Tax Evasion: Trust and Tax Morale in Contemporary Spain

    Directory of Open Access Journals (Sweden)

    Sandro Giachi

    2014-01-01

    Full Text Available This article tackles the problem of tax evasion from a sociological view. The rational action approach is integrated here with the concepts of trust and tax morale. The aim is to discover why people justify fi scal fraud or have lax tax morale. The main hypothesis maintained here is that tax system social factors ?such as trust? have an effect on the justifi cation of fraud. Using two survey datasets referred to the past ten years, we observe that tax morale seems to be mainly composed by trust in tax system, trust in other taxpayers as well as diverse contextual factors. Finally, I present an interpretive framework that takes into consideration individual factors as well as social and geographic dimensions of tax evasion in Spain.

  19. Relative Effects of Forward and Backward Planning on Goal Pursuit.

    Science.gov (United States)

    Park, Jooyoung; Lu, Fang-Chi; Hedgcock, William M

    2017-11-01

    Considerable research has shown that planning plays an important role in goal pursuit. But how does the way people plan affect goal pursuit? Research on this question is scarce. In the current research, we examined how planning the steps required for goal attainment in chronological order (i.e., forward planning) and reverse chronological order (i.e., backward planning) influences individuals' motivation for and perceptions of goal pursuit. Compared with forward planning, backward planning not only led to greater motivation, higher goal expectancy, and less time pressure but also resulted in better goal-relevant performance. We further demonstrated that this motivational effect occurred because backward planning allowed people to think of tasks required to reach their goals more clearly, especially when goals were complex to plan. These findings suggest that the way people plan matters just as much as whether or not they plan.

  20. Morphology of seahorse head hydrodynamically aids in capture of evasive prey.

    Science.gov (United States)

    Gemmell, Brad J; Sheng, Jian; Buskey, Edward J

    2013-01-01

    Syngnathid fish (seahorses, pipefish and sea dragons) are slow swimmers yet capture evasive prey (copepods) using a technique known as the 'pivot' feeding, which involves rapid movement to overcome prey escape capabilities. However, this feeding mode functions only at short range and requires approaching very closely to hydrodynamically sensitive prey without triggering an escape. Here we investigate the role of head morphology on prey capture using holographic and particle image velocimetry (PIV). We show that head morphology functions to create a reduced fluid deformation zone, minimizing hydrodynamic disturbance where feeding strikes occur (above the end of the snout), and permits syngnathid fish to approach highly sensitive copepod prey (Acartia tonsa) undetected. The results explain how these animals can successfully employ short range 'pivot' feeding effectively on evasive prey. The need to approach prey with stealth may have selected for a head shape that produces lower deformation rates than other fish.

  1. Xenopus-FV3 host-pathogen interactions and immune evasion.

    Science.gov (United States)

    Jacques, Robert; Edholm, Eva-Stina; Jazz, Sanchez; Odalys, Torres-Luquis; Francisco, De Jesús Andino

    2017-11-01

    We first review fundamental insights into anti-ranavirus immunity learned with the Xenopus laevis/ranavirus FV3 model that are generally applicable to ectothermic vertebrates. We then further investigate FV3 genes involved in immune evasion. Focusing on FV3 knockout (KO) mutants defective for a putative viral caspase activation and recruitment domain-containing (CARD)-like protein (Δ64R-FV3), a β-hydroxysteroid dehydrogenase homolog (Δ52L-FV3), and an immediate-early18kDa protein (FV3-Δ18K), we assessed the involvement of these viral genes in replication, dissemination and interaction with peritoneal macrophages in tadpole and adult frogs. Our results substantiate the role of 64R and 52L as critical immune evasion genes, promoting persistence and dissemination in the host by counteracting type III IFN in tadpoles and type I IFN in adult frogs. Comparably, the substantial accumulation of genome copy numbers and exacerbation of type I and III IFN gene expression responses but deficient release of infectious virus suggests that 18K is a viral regulatory gene. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Large fluctuations and fixation in evolutionary games

    International Nuclear Information System (INIS)

    Assaf, Michael; Mobilia, Mauro

    2010-01-01

    We study large fluctuations in evolutionary games belonging to the coordination and anti-coordination classes. The dynamics of these games, modeling cooperation dilemmas, is characterized by a coexistence fixed point separating two absorbing states. We are particularly interested in the problem of fixation that refers to the possibility that a few mutants take over the entire population. Here, the fixation phenomenon is induced by large fluctuations and is investigated by a semiclassical WKB (Wentzel–Kramers–Brillouin) theory generalized to treat stochastic systems possessing multiple absorbing states. Importantly, this method allows us to analyze the combined influence of selection and random fluctuations on the evolutionary dynamics beyond the weak selection limit often considered in previous works. We accurately compute, including pre-exponential factors, the probability distribution function in the long-lived coexistence state and the mean fixation time necessary for a few mutants to take over the entire population in anti-coordination games, and also the fixation probability in the coordination class. Our analytical results compare excellently with extensive numerical simulations. Furthermore, we demonstrate that our treatment is superior to the Fokker–Planck approximation when the selection intensity is finite

  3. Research on Multirobot Pursuit Task Allocation Algorithm Based on Emotional Cooperation Factor

    Directory of Open Access Journals (Sweden)

    Baofu Fang

    2014-01-01

    Full Text Available Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots’ individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm.

  4. Expansion of direction space around the cardinal axes revealed by smooth pursuit eye movements

    Science.gov (United States)

    Krukowski, Anton E.; Stone, Leland S.

    2005-01-01

    It is well established that perceptual direction discrimination shows an oblique effect; thresholds are higher for motion along diagonal directions than for motion along cardinal directions. Here, we compare simultaneous direction judgments and pursuit responses for the same motion stimuli and find that both pursuit and perceptual thresholds show similar anisotropies. The pursuit oblique effect is robust under a wide range of experimental manipulations, being largely resistant to changes in trajectory (radial versus tangential motion), speed (10 versus 25 deg/s), directional uncertainty (blocked versus randomly interleaved), and cognitive state (tracking alone versus concurrent tracking and perceptual tasks). Our data show that the pursuit oblique effect is caused by an effective expansion of direction space surrounding the cardinal directions and the requisite compression of space for other directions. This expansion suggests that the directions around the cardinal directions are in some way overrepresented in the visual cortical pathways that drive both smooth pursuit and perception.

  5. Stochastic Analysis 2010

    CERN Document Server

    Crisan, Dan

    2011-01-01

    "Stochastic Analysis" aims to provide mathematical tools to describe and model high dimensional random systems. Such tools arise in the study of Stochastic Differential Equations and Stochastic Partial Differential Equations, Infinite Dimensional Stochastic Geometry, Random Media and Interacting Particle Systems, Super-processes, Stochastic Filtering, Mathematical Finance, etc. Stochastic Analysis has emerged as a core area of late 20th century Mathematics and is currently undergoing a rapid scientific development. The special volume "Stochastic Analysis 2010" provides a sa

  6. A Monte-Carlo game theoretic approach for Multi-Criteria Decision Making under uncertainty

    Science.gov (United States)

    Madani, Kaveh; Lund, Jay R.

    2011-05-01

    Game theory provides a useful framework for studying Multi-Criteria Decision Making problems. This paper suggests modeling Multi-Criteria Decision Making problems as strategic games and solving them using non-cooperative game theory concepts. The suggested method can be used to prescribe non-dominated solutions and also can be used as a method to predict the outcome of a decision making problem. Non-cooperative stability definitions for solving the games allow consideration of non-cooperative behaviors, often neglected by other methods which assume perfect cooperation among decision makers. To deal with the uncertainty in input variables a Monte-Carlo Game Theory (MCGT) approach is suggested which maps the stochastic problem into many deterministic strategic games. The games are solved using non-cooperative stability definitions and the results include possible effects of uncertainty in input variables on outcomes. The method can handle multi-criteria multi-decision-maker problems with uncertainty. The suggested method does not require criteria weighting, developing a compound decision objective, and accurate quantitative (cardinal) information as it simplifies the decision analysis by solving problems based on qualitative (ordinal) information, reducing the computational burden substantially. The MCGT method is applied to analyze California's Sacramento-San Joaquin Delta problem. The suggested method provides insights, identifies non-dominated alternatives, and predicts likely decision outcomes.

  7. A game-theoretic formulation of the homogeneous self-reconfiguration problem

    KAUST Repository

    Pickem, Daniel; Egerstedt, Magnus; Shamma, Jeff S.

    2015-01-01

    In this paper we formulate the homogeneous two- and three-dimensional self-reconfiguration problem over discrete grids as a constrained potential game. We develop a game-theoretic learning algorithm based on the Metropolis-Hastings algorithm that solves the self-reconfiguration problem in a globally optimal fashion. Both a centralized and a fully decentralized algorithm are presented and we show that the only stochastically stable state is the potential function maximizer, i.e. the desired target configuration. These algorithms compute transition probabilities in such a way that even though each agent acts in a self-interested way, the overall collective goal of self-reconfiguration is achieved. Simulation results confirm the feasibility of our approach and show convergence to desired target configurations.

  8. A game-theoretic formulation of the homogeneous self-reconfiguration problem

    KAUST Repository

    Pickem, Daniel

    2015-12-15

    In this paper we formulate the homogeneous two- and three-dimensional self-reconfiguration problem over discrete grids as a constrained potential game. We develop a game-theoretic learning algorithm based on the Metropolis-Hastings algorithm that solves the self-reconfiguration problem in a globally optimal fashion. Both a centralized and a fully decentralized algorithm are presented and we show that the only stochastically stable state is the potential function maximizer, i.e. the desired target configuration. These algorithms compute transition probabilities in such a way that even though each agent acts in a self-interested way, the overall collective goal of self-reconfiguration is achieved. Simulation results confirm the feasibility of our approach and show convergence to desired target configurations.

  9. A note on the strong formulation of stochastic control problems with model uncertainty

    OpenAIRE

    Sirbu, Mihai

    2014-01-01

    We consider a  Markovian stochastic control problem with  model uncertainty. The controller (intelligent player) observes only the state, and, therefore, uses feedback (closed-loop) strategies.  The adverse player (nature) who does not have a direct interest in the payoff, chooses open-loop controls that parametrize Knightian uncertainty. This creates a two-step optimization  problem (like half of a game) over feedback strategies and open-loop controls. The main result is to sh...

  10. The Pursuit of Excellence through Education.

    Science.gov (United States)

    Ferrari, Michel, Ed.

    In this book theorists and researchers present a range of perspectives on how to promote excellence in education, providing an opportunity for expression to those who stress transformation of educational practice and those who emphasize individual abilities. In part 1, The Individual Pursuit of Excellence, the chapters are: (1) Learning from…

  11. The aesthetic and cultural pursuits of patients with stroke.

    Science.gov (United States)

    O'Connell, Clare; Cassidy, Aoife; O'Neill, Desmond; Moss, Hilary

    2013-11-01

    There has been an increasing interest in the arts in health care, with a suggestion that the arts and aesthetics can augment patient outcomes in stroke and other illnesses. Designing such programmes requires better knowledge of the artistic, aesthetic, and cultural pursuits of people affected by stroke. The aim of this study was to obtain the insights of this group about the profile of art and aesthetic activities in their lives and the influence of stroke on these aspects. Patients attending a stroke service were administered questions adapted from the Irish Arts Council's 2006 questionnaire on participation in aesthetics and cultural pursuits. Information was also collected on stroke type and present functional and cognitive status. Thirty-eight patients were interviewed. Of these, 20 were inpatients in hospital at the time of the interview and 18 were interviewed in an outpatient setting. Popular activities included mainstream cinema, listening to music, dancing, attending plays or musicals, and being outdoors. Many patients ceased these activities after their stroke, mostly because of health issues and inaccessibility. Most of the patients valued the importance of the arts in the health-care setting. This study gives a perspective for the first time on the aesthetic and cultural pursuits of stroke patients before their stroke. It portrays a wide variety of cultural and leisure activities and the cessation of these poststroke. It revealed the restrictions patients felt on gaining access to leisure pursuits both while in hospital and following discharge. Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  12. Cortical thickness of the dorsolateral prefrontal cortex predicts strategic choices in economic games.

    Science.gov (United States)

    Yamagishi, Toshio; Takagishi, Haruto; Fermin, Alan de Souza Rodrigues; Kanai, Ryota; Li, Yang; Matsumoto, Yoshie

    2016-05-17

    Human prosociality has been traditionally explained in the social sciences in terms of internalized social norms. Recent neuroscientific studies extended this traditional view of human prosociality by providing evidence that prosocial choices in economic games require cognitive control of the impulsive pursuit of self-interest. However, this view is challenged by an intuitive prosociality view emphasizing the spontaneous and heuristic basis of prosocial choices in economic games. We assessed the brain structure of 411 players of an ultimatum game (UG) and a dictator game (DG) and measured the strategic reasoning ability of 386. According to the reflective norm-enforcement view of prosociality, only those capable of strategically controlling their selfish impulses give a fair share in the UG, but cognitive control capability should not affect behavior in the DG. Conversely, we support the intuitive prosociality view by showing for the first time, to our knowledge, that strategic reasoning and cortical thickness of the dorsolateral prefrontal cortex were not related to giving in the UG but were negatively related to giving in the DG. This implies that the uncontrolled choice in the DG is prosocial rather than selfish, and those who have a thicker dorsolateral prefrontal cortex and are capable of strategic reasoning (goal-directed use of the theory of mind) control this intuitive drive for prosociality as a means to maximize reward when there are no future implications of choices.

  13. TAX EVASION AND MONEY LAUNDERING – WAYS OF EVADING THE PAYMENT OF THE STATE BUDGET LIABILITIES

    Directory of Open Access Journals (Sweden)

    Constantin AFANASE

    2005-01-01

    Full Text Available Tax evasion is an antisocial phenomenon to be fight against with all forces. By reducing collection oftaxes, this phenomenon abridges society of significant public resources which could be used forachieving some social and economic goals used by the whole society. It is known that since the oldtimes tax payers were looking for means of reducing tax liabilities through various and ingeniousmethods. Basis of tax evasion phenomenon are in the deep structures of human cerebration, in theselfish spirit of human being, which always tend to bring specific interest before overall interest.

  14. The informal sector in transition: Tax evasion in an institutional vacuum

    NARCIS (Netherlands)

    Gërxhani, K.

    2002-01-01

    This thesis discusses the informal sector mainly focusing on the study of tax evasion. Individuals' decision whether or not to evade taxes is the core of the studies presented here. The role of institutions in this individual decision is considered to be of crucial importance. As a natural

  15. Legal Considerations of Tax Evasion and Tax Avoidance

    OpenAIRE

    Dániel Deák

    2004-01-01

    The study of fiscal non-compliance - in particular, that of tax evasion - is quite extensive in the literature of economics. Lawyers do not show much interest in fiscal anomalies. An exception for this is perhaps tax avoidance which is usually interpreted as the problem of the form and substance. Apart from the modest interest in irregularities in fiscal law, the legal theories of obedience, or disobedience, and coherence have grown significantly, thanks to the precept of William Ross on prim...

  16. Malaria parasite evasion of classical complement pathway attack

    DEFF Research Database (Denmark)

    Larsen, Mads Delbo; Ditlev, Sisse; Olmos, Rafael Bayarri

    2017-01-01

    of the protective antibodies that are gradually acquired in response to P. falciparum-IEs. Although this response is dominated by IgG1 and IgG3, complement-mediated attack following activation of the classical pathway does not appear to be a major effector mechanism. We hypothesized that this is related to the knob...... is that the knob-restricted expression of PfEMP1 on the IE surface may serve as a hitherto unappreciated immune evasion mechanism employed by P. falciparum parasites....

  17. Evasion of CO2 from streams - the dominant component of the carbon export through the aquatic conduit in a boreal landscape.

    Science.gov (United States)

    Wallin, Marcus B; Grabs, Thomas; Buffam, Ishi; Laudon, Hjalmar; Agren, Ånneli; Öquist, Mats G; Bishop, Kevin

    2013-03-01

    Evasion of gaseous carbon (C) from streams is often poorly quantified in landscape C budgets. Even though the potential importance of the capillary network of streams as C conduits across the land-water-atmosphere interfaces is sometimes mentioned, low-order streams are often left out of budget estimates due to being poorly characterized in terms of gas exchange and even areal surface coverage. We show that evasion of C is greater than all the total dissolved C (both organic and inorganic) exported downstream in the waters of a boreal landscape. In this study evasion of carbon dioxide (CO2 ) from running waters within a 67 km(2) boreal catchment was studied. During a 4 year period (2006-2009) 13 streams were sampled on 104 different occasions for dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). From a locally determined model of gas exchange properties, we estimated the daily CO2 evasion with a high-resolution (5 × 5 m) grid-based stream evasion model comprising the entire ~100 km stream network. Despite the low areal coverage of stream surface, the evasion of CO2 from the stream network constituted 53% (5.0 (±1.8) g C m(-2)  yr(-1) ) of the entire stream C flux (9.6 (±2.4) g C m(-2)  yr(-1) ) (lateral as DIC, DOC, and vertical as CO2 ). In addition, 72% of the total CO2 loss took place already in the first- and second-order streams. This study demonstrates the importance of including CO2 evasion from low-order boreal streams into landscape C budgets as it more than doubled the magnitude of the aquatic conduit for C from this landscape. Neglecting this term will consequently result in an overestimation of the terrestrial C sink strength in the boreal landscape. © 2012 Blackwell Publishing Ltd.

  18. Hierarchical brain networks active in approach and avoidance goal pursuit

    Directory of Open Access Journals (Sweden)

    Jeffrey Martin Spielberg

    2013-06-01

    Full Text Available Effective approach/avoidance goal pursuit is critical for attaining long-term health and well-being. Research on the neural correlates of key goal pursuit processes (e.g., motivation has long been of interest, with lateralization in prefrontal cortex being a particularly fruitful target of investigation. However, this literature has often been limited by a lack of spatial specificity and has not delineated the precise aspects of approach/avoidance motivation involved. Additionally, the relationships among brain regions (i.e., network connectivity vital to goal pursuit remain largely unexplored. Specificity in location, process, and network relationship is vital for moving beyond gross characterizations of function and identifying the precise cortical mechanisms involved in motivation. The present paper integrates research using more spatially specific methodologies (e.g., functional magnetic resonance imaging with the rich psychological literature on approach/avoidance to propose an integrative network model that takes advantage of the strengths of each of these literatures.

  19. Hierarchical brain networks active in approach and avoidance goal pursuit.

    Science.gov (United States)

    Spielberg, Jeffrey M; Heller, Wendy; Miller, Gregory A

    2013-01-01

    Effective approach/avoidance goal pursuit is critical for attaining long-term health and well-being. Research on the neural correlates of key goal-pursuit processes (e.g., motivation) has long been of interest, with lateralization in prefrontal cortex being a particularly fruitful target of investigation. However, this literature has often been limited by a lack of spatial specificity and has not delineated the precise aspects of approach/avoidance motivation involved. Additionally, the relationships among brain regions (i.e., network connectivity) vital to goal-pursuit remain largely unexplored. Specificity in location, process, and network relationship is vital for moving beyond gross characterizations of function and identifying the precise cortical mechanisms involved in motivation. The present paper integrates research using more spatially specific methodologies (e.g., functional magnetic resonance imaging) with the rich psychological literature on approach/avoidance to propose an integrative network model that takes advantage of the strengths of each of these literatures.

  20. A General Theory of Markovian Time Inconsistent Stochastic Control Problems

    DEFF Research Database (Denmark)

    Björk, Tomas; Murgochi, Agatha

    We develop a theory for stochastic control problems which, in various ways, are time inconsistent in the sense that they do not admit a Bellman optimality principle. We attach these problems by viewing them within a game theoretic framework, and we look for Nash subgame perfect equilibrium points...... examples of time inconsistency in the literature are easily seen to be special cases of the present theory. We also prove that for every time inconsistent problem, there exists an associated time consistent problem such that the optimal control and the optimal value function for the consistent problem...

  1. Tax evasion between fiscal and penalty

    Directory of Open Access Journals (Sweden)

    Andreea Mihaela Corîci

    2017-12-01

    Full Text Available Although in present times a big importance is given to combating and preventing tax evasion, as well as to all tax frauds, there are, however, people who are tax evaders from the point of view of the criminal body, who manage to ease of payment of tax liabilities to the state. By imposing more drastic or lighter penalties, it is attempted to determine the taxpayer in order not to escape the payment of taxes and to commit the crime.If for the financial controlling authority a fiscal crime has a direct impact on the budget of a certain area, the fiscal action is a criminal one for the criminal authority.

  2. Experimental evaluation of user performance in a pursuit tracking task with multimodal feedback

    Directory of Open Access Journals (Sweden)

    Obrenović Željko

    2004-01-01

    Full Text Available In this paper we describe the results of experimental evaluation of user performance in a pursuit-tracking task with multimodal feedback. Our experimental results indicate that audio can significantly improve the accuracy of pursuit tracking. Experiments with 19 participants have shown that addition of acoustic modalities reduces the error during pursuit tracking for up to 19%. Moreover, experiments indicated the existence of perceptual boundaries of multimodal HCI for different scene complexity and target speeds. We have also shown that the most appealing paradigms are not the most effective ones, which necessitates a careful quantitative analysis of proposed multimodal HCI paradigms.

  3. Stochastic and non-stochastic effects - a conceptual analysis

    International Nuclear Information System (INIS)

    Karhausen, L.R.

    1980-01-01

    The attempt to divide radiation effects into stochastic and non-stochastic effects is discussed. It is argued that radiation or toxicological effects are contingently related to radiation or chemical exposure. Biological effects in general can be described by general laws but these laws never represent a necessary connection. Actually stochastic effects express contingent, or empirical, connections while non-stochastic effects represent semantic and non-factual connections. These two expressions stem from two different levels of discourse. The consequence of this analysis for radiation biology and radiation protection is discussed. (author)

  4. Reward action in the initiation of smooth pursuit eye movements

    OpenAIRE

    Joshua, Mati; Lisberger, Stephen G.

    2012-01-01

    Reward has a powerful influence on motor behavior. To probe how and where reward systems alter motor behavior, we studied smooth pursuit eye movements in monkeys trained to associate the color of a visual cue with the size of the reward to be issued at the end of the target motion. When the tracking task presented two different colored targets that moved orthogonally, monkeys biased the initiation of pursuit towards the direction of motion of the target that led to larger reward. The bias was...

  5. A Pursuit Theory Account for the Perception of Common Motion in Motion Parallax.

    Science.gov (United States)

    Ratzlaff, Michael; Nawrot, Mark

    2016-09-01

    The visual system uses an extraretinal pursuit eye movement signal to disambiguate the perception of depth from motion parallax. Visual motion in the same direction as the pursuit is perceived nearer in depth while visual motion in the opposite direction as pursuit is perceived farther in depth. This explanation of depth sign applies to either an allocentric frame of reference centered on the fixation point or an egocentric frame of reference centered on the observer. A related problem is that of depth order when two stimuli have a common direction of motion. The first psychophysical study determined whether perception of egocentric depth order is adequately explained by a model employing an allocentric framework, especially when the motion parallax stimuli have common rather than divergent motion. A second study determined whether a reversal in perceived depth order, produced by a reduction in pursuit velocity, is also explained by this model employing this allocentric framework. The results show than an allocentric model can explain both the egocentric perception of depth order with common motion and the perceptual depth order reversal created by a reduction in pursuit velocity. We conclude that an egocentric model is not the only explanation for perceived depth order in these common motion conditions. © The Author(s) 2016.

  6. Robust Matching Pursuit Extreme Learning Machines

    Directory of Open Access Journals (Sweden)

    Zejian Yuan

    2018-01-01

    Full Text Available Extreme learning machine (ELM is a popular learning algorithm for single hidden layer feedforward networks (SLFNs. It was originally proposed with the inspiration from biological learning and has attracted massive attentions due to its adaptability to various tasks with a fast learning ability and efficient computation cost. As an effective sparse representation method, orthogonal matching pursuit (OMP method can be embedded into ELM to overcome the singularity problem and improve the stability. Usually OMP recovers a sparse vector by minimizing a least squares (LS loss, which is efficient for Gaussian distributed data, but may suffer performance deterioration in presence of non-Gaussian data. To address this problem, a robust matching pursuit method based on a novel kernel risk-sensitive loss (in short KRSLMP is first proposed in this paper. The KRSLMP is then applied to ELM to solve the sparse output weight vector, and the new method named the KRSLMP-ELM is developed for SLFN learning. Experimental results on synthetic and real-world data sets confirm the effectiveness and superiority of the proposed method.

  7. The underground economy in the U.S.A.: preliminary new evidence on the impact of income tax rates (and other factors on aggregate tax evasion 1975-2008

    Directory of Open Access Journals (Sweden)

    Richard J. Cebula

    2014-12-01

    Full Text Available This empirical study seeks to identify determinants of the underground economy in the U.S. in the form of aggregate federal personal income tax evasion over the period 1975-2008, with a specific focus upon the impact of higher federal income tax rates on tax evasion. In this study, we use the most recent data available on aggregate personal income tax evasion, data that are derived from the General Currency Ratio Model and measured in the form of the ratio of unreported AGI to reported AGI. Most other studies of federal income tax evasion for the U.S. do not use data this current. It is found that the impact of increases in the federal income tax rate on aggregate personal income tax evasion may, on balance, be ambiguous, possibly suggesting that the income effect is negative and outweighs the positive substitution effect for the representative taxpayer. It is also found that the degree of aggregate personal income tax evasion may be an increasing function of the percentage of federal personal income tax returns characterized by itemized deductions and a decreasing function of the Tax Reform Act of 1986 (during the first two years of implementation, the ratio of the tax free interest rate yield on high grade municipals to the interest rate yield on ten year Treasury notes, and higher audit rates of filed federal income tax returns (as a measure of risk from tax evasion by IRS personnel. Finally, unpopular wars may provide a secondary benefit for and therefore act as an inducement for greater tax evasion.

  8. Cheating, Emotions, and Rationality: An Experiment on Tax Evasion

    OpenAIRE

    Giorgio Coricelli; Mateus Joffily; Claude Montmarquette; Marie Claire Villeval

    2010-01-01

    International audience; The economics-of-crime approach usually ignores the emotional cost and benefit of cheating. In this paper, we investigate the relationships between emotions, deception, and rational decision-making by means of an experiment on tax evasion. Emotions are measured by skin conductance responses and self-reports. We show that the intensity of anticipated and anticipatory emotions before reporting positively correlates with both the decision to cheat and the proportion of ev...

  9. Normal aging affects movement execution but not visual motion working memory and decision-making delay during cue-dependent memory-based smooth-pursuit.

    Science.gov (United States)

    Fukushima, Kikuro; Barnes, Graham R; Ito, Norie; Olley, Peter M; Warabi, Tateo

    2014-07-01

    Aging affects virtually all functions including sensory/motor and cognitive activities. While retinal image motion is the primary input for smooth-pursuit, its efficiency/accuracy depends on cognitive processes. Elderly subjects exhibit gain decrease during initial and steady-state pursuit, but reports on latencies are conflicting. Using a cue-dependent memory-based smooth-pursuit task, we identified important extra-retinal mechanisms for initial pursuit in young adults including cue information priming and extra-retinal drive components (Ito et al. in Exp Brain Res 229:23-35, 2013). We examined aging effects on parameters for smooth-pursuit using the same tasks. Elderly subjects were tested during three task conditions as previously described: memory-based pursuit, simple ramp-pursuit just to follow motion of a single spot, and popping-out of the correct spot during memory-based pursuit to enhance retinal image motion. Simple ramp-pursuit was used as a task that did not require visual motion working memory. To clarify aging effects, we then compared the results with the previous young subject data. During memory-based pursuit, elderly subjects exhibited normal working memory of cue information. Most movement-parameters including pursuit latencies differed significantly between memory-based pursuit and simple ramp-pursuit and also between young and elderly subjects. Popping-out of the correct spot motion was ineffective for enhancing initial pursuit in elderly subjects. However, the latency difference between memory-based pursuit and simple ramp-pursuit in individual subjects, which includes decision-making delay in the memory task, was similar between the two groups. Our results suggest that smooth-pursuit latencies depend on task conditions and that, although the extra-retinal mechanisms were functional for initial pursuit in elderly subjects, they were less effective.

  10. Keep your eyes on the ball: smooth pursuit eye movements enhance prediction of visual motion.

    Science.gov (United States)

    Spering, Miriam; Schütz, Alexander C; Braun, Doris I; Gegenfurtner, Karl R

    2011-04-01

    Success of motor behavior often depends on the ability to predict the path of moving objects. Here we asked whether tracking a visual object with smooth pursuit eye movements helps to predict its motion direction. We developed a paradigm, "eye soccer," in which observers had to either track or fixate a visual target (ball) and judge whether it would have hit or missed a stationary vertical line segment (goal). Ball and goal were presented briefly for 100-500 ms and disappeared from the screen together before the perceptual judgment was prompted. In pursuit conditions, the ball moved towards the goal; in fixation conditions, the goal moved towards the stationary ball, resulting in similar retinal stimulation during pursuit and fixation. We also tested the condition in which the goal was fixated and the ball moved. Motion direction prediction was significantly better in pursuit than in fixation trials, regardless of whether ball or goal served as fixation target. In both fixation and pursuit trials, prediction performance was better when eye movements were accurate. Performance also increased with shorter ball-goal distance and longer presentation duration. A longer trajectory did not affect performance. During pursuit, an efference copy signal might provide additional motion information, leading to the advantage in motion prediction.

  11. Stochastic Equilibria under Imprecise Deviations in Terminal-Reward Concurrent Games

    Directory of Open Access Journals (Sweden)

    Patricia Bouyer

    2016-09-01

    Full Text Available We study the existence of mixed-strategy equilibria in concurrent games played on graphs. While existence is guaranteed with safety objectives for each player, Nash equilibria need not exist when players are given arbitrary terminal-reward objectives, and their existence is undecidable with qualitative reachability objectives (and only three players. However, these results rely on the fact that the players can enforce infinite plays while trying to improve their payoffs. In this paper, we introduce a relaxed notion of equilibria, where deviations are imprecise. We prove that contrary to Nash equilibria, such (stationary equilibria always exist, and we develop a PSPACE algorithm to compute one.

  12. Hijacking Complement Regulatory Proteins for Bacterial Immune Evasion.

    Science.gov (United States)

    Hovingh, Elise S; van den Broek, Bryan; Jongerius, Ilse

    2016-01-01

    The human complement system plays an important role in the defense against invading pathogens, inflammation and homeostasis. Invading microbes, such as bacteria, directly activate the complement system resulting in the formation of chemoattractants and in effective labeling of the bacteria for phagocytosis. In addition, formation of the membrane attack complex is responsible for direct killing of Gram-negative bacteria. In turn, bacteria have evolved several ways to evade complement activation on their surface in order to be able to colonize and invade the human host. One important mechanism of bacterial escape is attraction of complement regulatory proteins to the microbial surface. These molecules are present in the human body for tight regulation of the complement system to prevent damage to host self-surfaces. Therefore, recruitment of complement regulatory proteins to the bacterial surface results in decreased complement activation on the microbial surface which favors bacterial survival. This review will discuss recent advances in understanding the binding of complement regulatory proteins to the bacterial surface at the molecular level. This includes, new insights that have become available concerning specific conserved motives on complement regulatory proteins that are favorable for microbial binding. Finally, complement evasion molecules are of high importance for vaccine development due to their dominant role in bacterial survival, high immunogenicity and homology as well as their presence on the bacterial surface. Here, the use of complement evasion molecules for vaccine development will be discussed.

  13. Toward realistic pursuit-evasion using a roadmap-based approach

    KAUST Repository

    Rodriguez, Samuel; Denny, Jory; Burgos, Juan; Mahadevan, Aditya; Manavi, Kasra; Murray, Luke; Kodochygov, Anton; Zourntos, Takis; Amato, Nancy M.

    2011-01-01

    be applied to more realistic scenarios than are typically studied in most previous work, including agents moving in 3D environments such as terrains, multi-story buildings, and dynamic environments. We also support more realistic three-dimensional visibility

  14. Regional-scale lateral carbon transport and CO2 evasion in temperate stream catchments

    Science.gov (United States)

    Magin, Katrin; Somlai-Haase, Celia; Schäfer, Ralf B.; Lorke, Andreas

    2017-11-01

    Inland waters play an important role in regional to global-scale carbon cycling by transporting, processing and emitting substantial amounts of carbon, which originate mainly from their catchments. In this study, we analyzed the relationship between terrestrial net primary production (NPP) and the rate at which carbon is exported from the catchments in a temperate stream network. The analysis included more than 200 catchment areas in southwest Germany, ranging in size from 0.8 to 889 km2 for which CO2 evasion from stream surfaces and downstream transport with stream discharge were estimated from water quality monitoring data, while NPP in the catchments was obtained from a global data set based on remote sensing. We found that on average 13.9 g C m-2 yr-1 (corresponding to 2.7 % of terrestrial NPP) are exported from the catchments by streams and rivers, in which both CO2 evasion and downstream transport contributed about equally to this flux. The average carbon fluxes in the catchments of the study area resembled global and large-scale zonal mean values in many respects, including NPP, stream evasion and the carbon export per catchment area in the fluvial network. A review of existing studies on aquatic-terrestrial coupling in the carbon cycle suggests that the carbon export per catchment area varies in a relatively narrow range, despite a broad range of different spatial scales and hydrological characteristics of the study regions.

  15. Triadic and collaborative play by gorillas in social games with objects.

    Science.gov (United States)

    Tanner, Joanne E; Byrne, Richard W

    2010-07-01

    Interaction with others over objects has until recently been thought lacking in the social play of non-human great apes, in contrast to that of children; even now, only bonobos have been observed to engage in social play involving objects. Human children's triadic interactions with objects involve joint attention, showing and giving, communication that maintains interaction, and sharing of emotions and experiences. We question assertions that chimpanzees, and non-human great apes in general, lack the key characteristics of children's collaborative play. Here, we show that zoo gorillas play games that are both triadic and collaborative. These games were videotaped at the San Francisco Zoo in five different years and involved five different pairings of gorillas. The context was in most cases playfully competitive, involving objects such as balls, bags and leather pieces as foci of joint attention; the ostensible goal in most games was to gain or keep possession of a particular object. In some episodes, roles as possessor or pursuer of an object were exchanged many times; in others, one gorilla retained possession of an object but encouraged pursuit from a partner. Through gaze and gesture, gorillas invited others to: share interest in and attention to objects; share patterns of play; and re-engage after breaks in play. Sometimes, gorillas would assist others in their efforts to engage in collaborative play: older gorillas encouraged younger partners by 'self-handicapping' their own actions. Collaborative games may occur later in the ontogeny of gorillas than in humans, and depend on the challenges and artifacts available in a particular group's habitat.

  16. Avoidance goal pursuit depletes self-regulatory resources

    NARCIS (Netherlands)

    Oertig, D.; Schüler, J.; Schnelle, J.; Brandstätter, V.; Roskes, M.; Elliot, A.J.

    2013-01-01

    Objective: Research on the strength model of self-regulation is burgeoning, but little empirical work has focused on the link between distinct types of daily goal pursuit and the depletion of self-regulatory resources. Here we conducted two studies on the link between avoidance goals and resource

  17. Avoidance goal pursuit depletes self-regulatory resources

    NARCIS (Netherlands)

    Oertig, Daniela; Schüler, Julia; Schnelle, Jessica; Brandstätter, Veronika; Roskes, Marieke; Elliot, Andrew J.

    Objective: Research on the strength model of self-regulation is burgeoning, but little empirical work has focused on the link between distinct types of daily goal pursuit and the depletion of self-regulatory resources. The authors conducted two studies on the link between avoidance goals and

  18. Complexity Dynamic Character Analysis of Retailers Based on the Share of Stochastic Demand and Service

    Directory of Open Access Journals (Sweden)

    Junhai Ma

    2017-01-01

    Full Text Available Apart from the price fluctuation, the retailers’ service level becomes another key factor that affects the market demand. This paper depicts a modified price and demand game model based on the stochastic demand and the retailer’s service level which influences the market demand decided by customers’ preference, while the market demand is stochastic in this model. We explore how the price adjustment speed affects the stability of the supply chain system with respect to service level and stochastic demand. The dynamic behavior of the system is researched by simulation and the stability domain and the bifurcation phenomenon are shown clearly. The largest Lyapunov exponent and the chaotic attractor are also given to confirm the chaotic characteristic of the system. The simulation results indicate that relatively small price adjustment speed may maintain the system at stable state. With the price adjustment speed gradually increasing, the price system gets unstable and finally becomes chaotic. This chaotic phenomenon will perturb the product market and this phenomenon should be controlled to keep the system stay in the stable region. So the chaos control is done and the chaos can be controlled completely. The conclusion makes significant contribution to the system referring to the price fluctuation based on the service level and stochastic demand.

  19. Tumor evasion from immune control: Strategies of a MISS to become a MASS

    International Nuclear Information System (INIS)

    D'Onofrio, Alberto

    2007-01-01

    We biologically describe the phenomenon of the evasion of tumors from immune surveillance where tumor cells, initially constrained to exist in a microscopic steady state (MISS) elaborate strategies to evade from the immune control and to reach a macroscopic steady state (MASS). We, then, describe 'evasion' as a long term loss of equilibrium in a framework of prey-predator-like models with adiabatic varying parameters, whose changes reflect the evolutionary adaptation of the tumor in a 'hostile' environment by means of the elaboration of new strategies of survival. Similarities and differences between the present work and the interesting seminal paper [Kuznetsov VA, Knott GD. Modeling tumor regrowth and immunotherapy. Math Comput Model 2001;33:1275-87] are discussed. We also propose and study a model of clonal resistance to the immune control with slowly varying adaptive mutation parameter

  20. Tumor evasion from immune control: Strategies of a MISS to become a MASS

    Energy Technology Data Exchange (ETDEWEB)

    D' Onofrio, Alberto [Department of Epidemiology and Biostatistics, European Institute of Oncology, Via Ripamonti 435, I-20141 Milan (Italy)]. E-mail: alberto.d' onofrio@ieo.it

    2007-01-15

    We biologically describe the phenomenon of the evasion of tumors from immune surveillance where tumor cells, initially constrained to exist in a microscopic steady state (MISS) elaborate strategies to evade from the immune control and to reach a macroscopic steady state (MASS). We, then, describe 'evasion' as a long term loss of equilibrium in a framework of prey-predator-like models with adiabatic varying parameters, whose changes reflect the evolutionary adaptation of the tumor in a 'hostile' environment by means of the elaboration of new strategies of survival. Similarities and differences between the present work and the interesting seminal paper [Kuznetsov VA, Knott GD. Modeling tumor regrowth and immunotherapy. Math Comput Model 2001;33:1275-87] are discussed. We also propose and study a model of clonal resistance to the immune control with slowly varying adaptive mutation parameter.

  1. An MHC class I immune evasion gene of Marek׳s disease virus.

    Science.gov (United States)

    Hearn, Cari; Preeyanon, Likit; Hunt, Henry D; York, Ian A

    2015-01-15

    Marek׳s disease virus (MDV) is a widespread α-herpesvirus of chickens that causes T cell tumors. Acute, but not latent, MDV infection has previously been shown to lead to downregulation of cell-surface MHC class I (Virology 282:198-205 (2001)), but the gene(s) involved have not been identified. Here we demonstrate that an MDV gene, MDV012, is capable of reducing surface expression of MHC class I on chicken cells. Co-expression of an MHC class I-binding peptide targeted to the endoplasmic reticulum (bypassing the requirement for the TAP peptide transporter) partially rescued MHC class I expression in the presence of MDV012, suggesting that MDV012 is a TAP-blocking MHC class I immune evasion protein. This is the first unique non-mammalian MHC class I immune evasion gene identified, and suggests that α-herpesviruses have conserved this function for at least 100 million years. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. COMPARATIVE ANALYSIS OF TAX EVASION BETWEEN MOLDOVA AND ROMANIA

    Directory of Open Access Journals (Sweden)

    OANA-CARMEN RĂVAŞ

    2015-12-01

    Full Text Available Tax evasion is actually failure by the taxpayer, tax liabilities. And the negative effects of this are felt directly on the level of tax revenue receipts, causing major distortions in the functioning of the market mechanism. It is believed that the first cause of fraud is itself impossible, fairer tax system in which develops based on the principle of declaring taxpayer benefiting from a presumption of honesty and that is a temptation to hide.

  3. Tax havens: Features, operations and solving tax evasion problems

    OpenAIRE

    Obradović-Ćuk, Jelena; Mitić, Petar; Dinić, Vladimir

    2016-01-01

    Tax haven offers minimal or no tax liability to foreign individuals and enterprises in economically and politically stable environment, where little or no financial information is shared with foreign tax authorities. The aim of this research is to create a comprehensive overview of the characteristics and operations of tax havens, as well as to point out to the ways to overcome the problem of tax evasion. The methodology used in the work is characteristic of social science research: analysis,...

  4. Tax evasion – Notion and means to commit it

    Directory of Open Access Journals (Sweden)

    Diana G. IONAŞ

    2012-01-01

    Full Text Available Tax evasion is the circumvention, by any means, from the enforcement or payment of taxes, contributions or any amounts owed to the state budget, the local budget, the state social insurance budget and the budgets for special funds by Romanian or foreign natural persons or companies, commonly referred to as tax payers in the text of the law. It is currently present under various methods and represents a direct and dangerous threat for society’s stability.

  5. Viral Evasion of Natural Killer Cell Activation

    Directory of Open Access Journals (Sweden)

    Yi Ma

    2016-04-01

    Full Text Available Natural killer (NK cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections.

  6. Mechanism of immune evasion in breast cancer

    Science.gov (United States)

    Wang, Mozhi; Zhang, Changwang; Song, Yongxi; Wang, Zhenning; Wang, Yaojia; Luo, Fang; Xu, Yujie; Zhao, Yi; Wu, Zhonghua; Xu, Yingying

    2017-01-01

    Breast cancer (BC) is the most common malignant tumor among women, with high morbidity and mortality. Its onset, development, metastasis, and prognosis vary among individuals due to the interactions between tumors and host immunity. Many diverse mechanisms have been associated with BC, with immune evasion being the most widely studied to date. Tumor cells can escape from the body’s immune response, which targets abnormal components and foreign bodies, using different approaches including modification of surface antigens and modulation of the surrounding environment. In this review, we summarize the mechanisms and factors that impact the immunoediting process and analyze their functions in detail. PMID:28352189

  7. Viral Evasion of Natural Killer Cell Activation.

    Science.gov (United States)

    Ma, Yi; Li, Xiaojuan; Kuang, Ersheng

    2016-04-12

    Natural killer (NK) cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections.

  8. Unpredictability of escape trajectory explains predator evasion ability and microhabitat preference of desert rodents.

    Science.gov (United States)

    Moore, Talia Y; Cooper, Kimberly L; Biewener, Andrew A; Vasudevan, Ramanarayan

    2017-09-05

    Mechanistically linking movement behaviors and ecology is key to understanding the adaptive evolution of locomotion. Predator evasion, a behavior that enhances fitness, may depend upon short bursts or complex patterns of locomotion. However, such movements are poorly characterized by existing biomechanical metrics. We present methods based on the entropy measure of randomness from Information Theory to quantitatively characterize the unpredictability of non-steady-state locomotion. We then apply the method by examining sympatric rodent species whose escape trajectories differ in dimensionality. Unlike the speed-regulated gait use of cursorial animals to enhance locomotor economy, bipedal jerboa (family Dipodidae) gait transitions likely enhance maneuverability. In field-based observations, jerboa trajectories are significantly less predictable than those of quadrupedal rodents, likely increasing predator evasion ability. Consistent with this hypothesis, jerboas exhibit lower anxiety in open fields than quadrupedal rodents, a behavior that varies inversely with predator evasion ability. Our unpredictability metric expands the scope of quantitative biomechanical studies to include non-steady-state locomotion in a variety of evolutionary and ecologically significant contexts.Biomechanical understanding of animal gait and maneuverability has primarily been limited to species with more predictable, steady-state movement patterns. Here, the authors develop a method to quantify movement predictability, and apply the method to study escape-related movement in several species of desert rodents.

  9. Tax evasion in transition: Outcome of an institutional clash? - Testing Feige's conjecture

    NARCIS (Netherlands)

    Gërxhani, K.

    2003-01-01

    A field survey of households was conducted in Tirana, Albania in 2000. A response rate of 89.3% yielded 1.340 valid questionnaires, allowing us to test Feige’s (1997) conjecture that more tax evasion will be observed, when formal and informal institutions clash. Respondents’ attitudes towards formal

  10. Evasion of CO2 injected into the ocean in the context of CO2 stabilization

    International Nuclear Information System (INIS)

    Kheshgi, Haroon S.

    2004-01-01

    The eventual evasion of injected CO 2 to the atmosphere is one consideration when assessing deep-sea disposal of CO 2 as a potential response option to climate change concerns. Evasion estimated using an ocean carbon cycle model is compared to long-term trajectories for future CO 2 emissions, including illustrative cases leading to stabilization of CO 2 concentration at various levels. Modeled residence time for CO 2 injected into the deep ocean exceeds the 100-year time-scale usually considered in scenarios for future emissions, and the potential impacts of climate change. Illustrative cases leading monotonically to constant CO 2 concentration have been highlighted by the Intergovernmental Panel on Climate Change to give guidance on possible timing of emission reductions that may be required to stabilize greenhouse gas concentrations at various levels. For stabilization cases considered, significant modeled evasion does not occur until long after CO 2 emissions have reached a maximum and begun to decline. Illustrative cases can also lead to a maximum in CO 2 concentration followed by a decline to slowly decreasing concentrations. In such cases, future injection of emissions into the deep ocean leads to lower maximum CO 2 concentration, with less effect on concentration later on in time

  11. Interleukin-36 cytokines may overcome microbial immune evasion strategies that inhibit interleukin-1 family signaling.

    Science.gov (United States)

    Jensen, Liselotte E

    2017-08-15

    Pathogens deploy immune evasion strategies to successfully establish infections within their hosts. Naturally, the host responds by acquiring mechanisms to counter these strategies. There is increasing evidence that the three interleukin-36 (IL-36) cytokines, IL-36α, IL-36β and IL-36γ, play important roles in host immunity. With a focus on the skin as a target for microbial and viral invasion, the current knowledge of IL-36 functions is reviewed. Furthermore, the hypothesis that the IL-36s have evolved to counteract virulence factors is presented using viruses as an example. The IL-36s are related to IL-1α, IL-1β, IL-18, and IL-33. Numerous viruses affecting the skin have developed immune evasion strategies that neutralize IL-1α, IL-1β, or IL-18 signaling or combinations of these pathways. Through small differences in activation mechanisms and receptor utilization, it is possible that IL-36 signaling may proceed unhindered in the presence of these viral inhibitors. Thus, one physiological function of the IL-36s may be to counteract microbial immune evasion. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  12. Attention is allocated closely ahead of the target during smooth pursuit eye movements: Evidence from EEG frequency tagging.

    Science.gov (United States)

    Chen, Jing; Valsecchi, Matteo; Gegenfurtner, Karl R

    2017-07-28

    It is under debate whether attention during smooth pursuit is centered right on the pursuit target or allocated preferentially ahead of it. Attentional deployment was previously probed using a secondary task, which might have altered attention allocation and led to inconsistent findings. We measured frequency-tagged steady-state visual evoked potentials (SSVEP) to measure attention allocation in the absence of any secondary probing task. The observers pursued a moving dot while stimuli flickering at different frequencies were presented at various locations ahead or behind the pursuit target. We observed a significant increase in EEG power at the flicker frequency of the stimulus in front of the pursuit target, compared to the frequency of the stimulus behind. When testing many different locations, we found that the enhancement was detectable up to about 1.5° ahead during pursuit, but vanished by 3.5°. In a control condition using attentional cueing during fixation, we did observe an enhanced EEG response to stimuli at this eccentricity, indicating that the focus of attention during pursuit is narrower than allowed for by the resolution of the attentional system. In a third experiment, we ruled out the possibility that the SSVEP enhancement was a byproduct of the catch-up saccades occurring during pursuit. Overall, we showed that attention is on average allocated ahead of the pursuit target during smooth pursuit. EEG frequency tagging seems to be a powerful technique that allows for the investigation of attention/perception implicitly when an overt task would be confounding. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Immune Evasion Mechanisms of Entamoeba histolytica: Progression to Disease.

    Science.gov (United States)

    Begum, Sharmin; Quach, Jeanie; Chadee, Kris

    2015-01-01

    Entamoeba histolytica (Eh) is a protozoan parasite that infects 10% of the world's population and results in 100,000 deaths/year from amebic dysentery and/or liver abscess. In most cases, this extracellular parasite colonizes the colon by high affinity binding to MUC2 mucin without disease symptoms, whereas in some cases, Eh triggers an aggressive inflammatory response upon invasion of the colonic mucosa. The specific host-parasite factors critical for disease pathogenesis are still not well characterized. From the parasite, the signature events that lead to disease progression are cysteine protease cleavage of the C-terminus of MUC2 that dissolves the mucus layer followed by Eh binding and cytotoxicity of the mucosal epithelium. The host mounts an ineffective excessive host pro-inflammatory response following contact with host cells that causes tissue damage and participates in disease pathogenesis as Eh escapes host immune clearance by mechanisms that are not completely understood. Ameba can modulate or destroy effector immune cells by inducing neutrophil apoptosis and suppressing respiratory burst or nitric oxide (NO) production from macrophages. Eh adherence to the host cells also induce multiple cytotoxic effects that can promote cell death through phagocytosis, apoptosis or by trogocytosis (ingestion of living cells) that might play critical roles in immune evasion. This review focuses on the immune evasion mechanisms that Eh uses to survive and induce disease manifestation in the host.

  14. America’s Underground Economy: Measuring the Size, Growth and Determinants of Income Tax Evasion in the U.S

    OpenAIRE

    Feige, Edgar L.; Cebula, Richard

    2011-01-01

    Abstract This study empirically investigates the extent of non compliance with the tax code and the determinants of federal income tax evasion in the U.S. Employing the most recent data we find that 18-19% of total reportable income is not properly reported to the IRS, giving rise to a “tax gap” approaching $500 billion dollars. Three time periods are studied, 1960-2008, 1970-2008, and 1980-2008. It is found across study periods that income tax evasion is an increasing function of the av...

  15. Linear–Quadratic Mean-Field-Type Games: A Direct Method

    Directory of Open Access Journals (Sweden)

    Tyrone E. Duncan

    2018-02-01

    Full Text Available In this work, a multi-person mean-field-type game is formulated and solved that is described by a linear jump-diffusion system of mean-field type and a quadratic cost functional involving the second moments, the square of the expected value of the state, and the control actions of all decision-makers. We propose a direct method to solve the game, team, and bargaining problems. This solution approach does not require solving the Bellman–Kolmogorov equations or backward–forward stochastic differential equations of Pontryagin’s type. The proposed method can be easily implemented by beginners and engineers who are new to the emerging field of mean-field-type game theory. The optimal strategies for decision-makers are shown to be in a state-and-mean-field feedback form. The optimal strategies are given explicitly as a sum of the well-known linear state-feedback strategy for the associated deterministic linear–quadratic game problem and a mean-field feedback term. The equilibrium cost of the decision-makers are explicitly derived using a simple direct method. Moreover, the equilibrium cost is a weighted sum of the initial variance and an integral of a weighted variance of the diffusion and the jump process. Finally, the method is used to compute global optimum strategies as well as saddle point strategies and Nash bargaining solution in state-and-mean-field feedback form.

  16. Game-Theoretical Design of an Adaptive Distributed Dissemination Protocol for VANETs.

    Science.gov (United States)

    Iza-Paredes, Cristhian; Mezher, Ahmad Mohamad; Aguilar Igartua, Mónica; Forné, Jordi

    2018-01-19

    Road safety applications envisaged for Vehicular Ad Hoc Networks (VANETs) depend largely on the dissemination of warning messages to deliver information to concerned vehicles. The intended applications, as well as some inherent VANET characteristics, make data dissemination an essential service and a challenging task in this kind of networks. This work lays out a decentralized stochastic solution for the data dissemination problem through two game-theoretical mechanisms. Given the non-stationarity induced by a highly dynamic topology, diverse network densities, and intermittent connectivity, a solution for the formulated game requires an adaptive procedure able to exploit the environment changes. Extensive simulations reveal that our proposal excels in terms of number of transmissions, lower end-to-end delay and reduced overhead while maintaining high delivery ratio, compared to other proposals.

  17. Supermodular Games and Potential Games

    NARCIS (Netherlands)

    Brânzei, R.; Mallozzi, L.; Tijs, S.H.

    2001-01-01

    Potential games and supermodular games are attractive games, especially because under certain conditions they possess pure Nash equilibria. Subclasses of games with a potential are considered which are also strategically equivalent to supermodular games. The focus is on two-person zero-sum games and

  18. Mathematical games, abstract games

    CERN Document Server

    Neto, Joao Pedro

    2013-01-01

    User-friendly, visually appealing collection offers both new and classic strategic board games. Includes abstract games for two and three players and mathematical games such as Nim and games on graphs.

  19. THE VALUE ADDED TAX AND THE EVASION CHAIN OF INTRA-COMMUNITARIAN VAT

    Directory of Open Access Journals (Sweden)

    Deliman Eugen

    2011-12-01

    Full Text Available The relationship IRS taxpayer runs the risk of turning into a psychological war in which, however, given the positions held, the IRS is by far on a favorable footing. Between the apparently excessively formal position held by the IRS, which seems to conceal behind the laws, and the sometimes forced interpretation of the laws, by the taxpayer, there are the courts of law, also disturbed by the legislative changes which appear to have entered a perpetual motion. The objective of the fiscal administration regarding the value added tax is to combat tax evasion and fraud. It is very important to combat evasion in the VAT field because it represents the indirect tax of the largest share in the consolidated general budget. VAT evasion represents the intention of not paying the tax, withholding or not declaring it, or requesting its refund which would not be fit, due to the exaggeration of the deductible amount of the VAT. The essential aim of the IRS inspector is to verify the correctness of the declared amount of the value added tax. It should also be observed whether the incorrectness is deliberate or whether it was due to misunderstanding, carelessness or the ignorance of the payer. In all cases judgment is necessary, as for the cases of negligence the amount to be paid must be corrected and accompanied by applying fines and / or penalties, and in the cases of intended fraud legal actions are to be applied in order to obtain a conviction. Deceitful deductions represent other methods for tax evasion and are undertaken based on fake invoices, invoices often used several times for deduction, or invoices related to purchases that have never been made. Thus there are examples of economic agents who have practiced the right to deduct the VAT due to the acquisition of goods which consisted in the property of other economic agents. In other cases noticed was the deduction of VAT on goods or services that were not included in the activities of the economic

  20. Linear Quadratic Mean Field Type Control and Mean Field Games with Common Noise, with Application to Production of an Exhaustible Resource

    Energy Technology Data Exchange (ETDEWEB)

    Graber, P. Jameson, E-mail: jameson-graber@baylor.edu [Baylor University, Department of Mathematics (United States)

    2016-12-15

    We study a general linear quadratic mean field type control problem and connect it to mean field games of a similar type. The solution is given both in terms of a forward/backward system of stochastic differential equations and by a pair of Riccati equations. In certain cases, the solution to the mean field type control is also the equilibrium strategy for a class of mean field games. We use this fact to study an economic model of production of exhaustible resources.

  1. Sparse reconstruction using distribution agnostic bayesian matching pursuit

    KAUST Repository

    Masood, Mudassir; Al-Naffouri, Tareq Y.

    2013-01-01

    A fast matching pursuit method using a Bayesian approach is introduced for sparse signal recovery. This method performs Bayesian estimates of sparse signals even when the signal prior is non-Gaussian or unknown. It is agnostic on signal statistics

  2. The Influence of Money on Goal Pursuit and Decision-Making: Understanding Money's Unique Impact on Goal Pursuit

    Science.gov (United States)

    Moran, Nora

    Previous research suggests that activating concepts of money and wealth can increase motivation to achieve personal goals. In this dissertation, I investigate how money affects pursuit of important personal goals, and how this motivation may be affected by goal attainability. In eight studies, I show that priming concepts of money and wealth leads individuals to pursue important personal goals to a greater degree than control groups, but only when a goal is more attainable. In contrast, when a goal is less attainable, those primed with money will be less likely to work towards goals relative to control groups. Furthermore, I examine why money may have a detrimental effect on motivation when individuals are faced with less attainable but important goals, and argue those primed with money become more concerned with maintaining a sense of efficacy, and thus disengage from pursuit when success is less certain. Thus, this research identifies the needs made salient by activating money--validating one's abilities. Finally, I show the relevance of these findings for consumer behavior, and discuss the additional implications of this work, as well as future research directions.

  3. Noncausal stochastic calculus

    CERN Document Server

    Ogawa, Shigeyoshi

    2017-01-01

    This book presents an elementary introduction to the theory of noncausal stochastic calculus that arises as a natural alternative to the standard theory of stochastic calculus founded in 1944 by Professor Kiyoshi Itô. As is generally known, Itô Calculus is essentially based on the "hypothesis of causality", asking random functions to be adapted to a natural filtration generated by Brownian motion or more generally by square integrable martingale. The intention in this book is to establish a stochastic calculus that is free from this "hypothesis of causality". To be more precise, a noncausal theory of stochastic calculus is developed in this book, based on the noncausal integral introduced by the author in 1979. After studying basic properties of the noncausal stochastic integral, various concrete problems of noncausal nature are considered, mostly concerning stochastic functional equations such as SDE, SIE, SPDE, and others, to show not only the necessity of such theory of noncausal stochastic calculus but ...

  4. Distractor Interference during Smooth Pursuit Eye Movements

    Science.gov (United States)

    Spering, Miriam; Gegenfurtner, Karl R.; Kerzel, Dirk

    2006-01-01

    When 2 targets for pursuit eye movements move in different directions, the eye velocity follows the vector average (S. G. Lisberger & V. P. Ferrera, 1997). The present study investigates the mechanisms of target selection when observers are instructed to follow a predefined horizontal target and to ignore a moving distractor stimulus. Results show…

  5. Game-theoretic modeling of curtailment rules and network investments with distributed generation

    International Nuclear Information System (INIS)

    Andoni, Merlinda; Robu, Valentin; Früh, Wolf-Gerrit; Flynn, David

    2017-01-01

    Highlights: •Comparative study on curtailment rules and their effects on RES profitability. •Proposal of novel fair curtailment rule which minimises generators’ disruption. •Modeling of private network upgrade as leader-follower (Stackelberg) game. •New model incorporating stochastic generation and variable demand. •New methodology for setting transmission charges in private network upgrade. -- Abstract: Renewable energy has achieved high penetration rates in many areas, leading to curtailment, especially if existing network infrastructure is insufficient and energy generated cannot be exported. In this context, Distribution Network Operators (DNOs) face a significant knowledge gap about how to implement curtailment rules that achieve desired operational objectives, but at the same time minimise disruption and economic losses for renewable generators. In this work, we study the properties of several curtailment rules widely used in UK renewable energy projects, and their effect on the viability of renewable generation investment. Moreover, we propose a new curtailment rule which guarantees fair allocation of curtailment amongst all generators with minimal disruption. Another key knowledge gap faced by DNOs is how to incentivise private network upgrades, especially in settings where several generators can use the same line against the payment of a transmission fee. In this work, we provide a solution to this problem by using tools from algorithmic game theory. Specifically, this setting can be modelled as a Stackelberg game between the private transmission line investor and local renewable generators, who are required to pay a transmission fee to access the line. We provide a method for computing the equilibrium of this game, using a model that captures the stochastic nature of renewable energy generation and demand. Finally, we use the practical setting of a grid reinforcement project from the UK and a large dataset of wind speed measurements and demand

  6. Multi-target consensus circle pursuit for multi-agent systems via a distributed multi-flocking method

    Science.gov (United States)

    Pei, Huiqin; Chen, Shiming; Lai, Qiang

    2016-12-01

    This paper studies the multi-target consensus pursuit problem of multi-agent systems. For solving the problem, a distributed multi-flocking method is designed based on the partial information exchange, which is employed to realise the pursuit of multi-target and the uniform distribution of the number of pursuing agents with the dynamic target. Combining with the proposed circle formation control strategy, agents can adaptively choose the target to form the different circle formation groups accomplishing a multi-target pursuit. The speed state of pursuing agents in each group converges to the same value. A Lyapunov approach is utilised to analyse the stability of multi-agent systems. In addition, a sufficient condition is given for achieving the dynamic target consensus pursuit, and which is then analysed. Finally, simulation results verify the effectiveness of the proposed approaches.

  7. Multivariate Analysis for the Choice and Evasion of the Student in a Higher Educational Institution from Southern of Santa Catarina, in Brazil

    Science.gov (United States)

    Queiroz, Fernanda Cristina Barbosa Pereira; Samohyl, Robert Wayne; Queiroz, Jamerson Viegas; Lima, Nilton Cesar; de Souza, Gustavo Henrique Silva

    2014-01-01

    This paper aims to develop and implement a method to identify the causes of the choice of a course and the reasons for evasion in higher education. This way, we sought to identify the factors that influence student choice to opt for Higher Education Institution parsed, as well as the factors influencing its evasion. The methodology employed was…

  8. More than just immune evasion: Hijacking complement by Plasmodium falciparum.

    Science.gov (United States)

    Schmidt, Christoph Q; Kennedy, Alexander T; Tham, Wai-Hong

    2015-09-01

    Malaria remains one of the world's deadliest diseases. Plasmodium falciparum is responsible for the most severe and lethal form of human malaria. P. falciparum's life cycle involves two obligate hosts: human and mosquito. From initial entry into these hosts, malaria parasites face the onslaught of the first line of host defence, the complement system. In this review, we discuss the complex interaction between complement and malaria infection in terms of hosts immune responses, parasite survival and pathogenesis of severe forms of malaria. We will focus on the role of complement receptor 1 and its associated polymorphisms in malaria immune complex clearance, as a mediator of parasite rosetting and as an entry receptor for P. falciparum invasion. Complement evasion strategies of P. falciparum parasites will also be highlighted. The sexual forms of the malaria parasites recruit the soluble human complement regulator Factor H to evade complement-mediated killing within the mosquito host. A novel evasion strategy is the deployment of parasite organelles to divert complement attack from infective blood stage parasites. Finally we outline the future challenge to understand the implications of these exploitation mechanisms in the interplay between successful infection of the host and pathogenesis observed in severe malaria. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. A game is a game is a game

    DEFF Research Database (Denmark)

    Jørgensen, Ida Kathrine Hammeleff

    2017-01-01

    Recently self-referentiality have occurred as a trend among game designers and have also enjoyed sporadic attention in academia. However, in academia, discussions of self-referential games often rest on proceduralist arguments and a too exclusive focus on the game object. This paper draws...... on the typology of meta-pictures developed by art historian J.W.T. Mitchell. Based on this typology, this paper discusses the notion of meta-games and suggest a broad conception of such games that includes not only the game object, but also the player and the discourse in which it is interpreted....

  10. Cyclic Matching Pursuits with Multiscale Time-frequency Dictionaries

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Christensen, Mads Græsbøll

    2010-01-01

    We generalize cyclic matching pursuit (CMP), propose an orthogonal variant, and examine their performance using multiscale time-frequency dictionaries in the sparse approximation of signals. Overall, we find that the cyclic approach of CMP produces signal models that have a much lower approximation...

  11. The Surface-Exposed Protein SntA Contributes to Complement Evasion in Zoonotic Streptococcus suis.

    Science.gov (United States)

    Deng, Simin; Xu, Tong; Fang, Qiong; Yu, Lei; Zhu, Jiaqi; Chen, Long; Liu, Jiahui; Zhou, Rui

    2018-01-01

    Streptococcus suis is an emerging zoonotic pathogen causing streptococcal toxic shock like syndrome (STSLS), meningitis, septicemia, and even sudden death in human and pigs. Serious septicemia indicates this bacterium can evade the host complement surveillance. In our previous study, a functionally unknown protein SntA of S. suis has been identified as a heme-binding protein, and contributes to virulence in pigs. SntA can interact with the host antioxidant protein AOP2 and consequently inhibit its antioxidant activity. In the present study, SntA is identified as a cell wall anchored protein that functions as an important player in S. suis complement evasion. The C3 deposition and membrane attack complex (MAC) formation on the surface of sntA -deleted mutant strain Δ sntA are demonstrated to be significantly higher than the parental strain SC-19 and the complementary strain CΔ sntA . The abilities of anti-phagocytosis, survival in blood, and in vivo colonization of Δ sntA are obviously reduced. SntA can interact with C1q and inhibit hemolytic activity via the classical pathway. Complement activation assays reveal that SntA can also directly activate classical and lectin pathways, resulting in complement consumption. These two complement evasion strategies may be crucial for the pathogenesis of this zoonotic pathogen. Concerning that SntA is a bifunctional 2',3'-cyclic nucleotide 2'-phosphodiesterase/3'-nucleotidase in many species of Gram-positive bacteria, these complement evasion strategies may have common biological significance.

  12. A Model of the Smooth Pursuit Eye Movement with Prediction and Learning

    Directory of Open Access Journals (Sweden)

    Davide Zambrano

    2010-01-01

    Full Text Available Smooth pursuit is one of the five main eye movements in humans, consisting of tracking a steadily moving visual target. Smooth pursuit is a good example of a sensory-motor task that is deeply based on prediction: tracking a visual target is not possible by correcting the error between the eye and the target position or velocity with a feedback loop, but it is only possible by predicting the trajectory of the target. This paper presents a model of smooth pursuit based on prediction and learning. It starts from amodel of the neuro-physiological system proposed by Shibata and Schaal (Shibata et al., Neural Networks, vol. 18, pp. 213-224, 2005. The learning component added here decreases the prediction time in the case of target dynamics already experienced by the system. In the implementation described here, the convergence time is, after the learning phase, 0.8 s.

  13. Visual sensitivity for luminance and chromatic stimuli during the execution of smooth pursuit and saccadic eye movements.

    Science.gov (United States)

    Braun, Doris I; Schütz, Alexander C; Gegenfurtner, Karl R

    2017-07-01

    Visual sensitivity is dynamically modulated by eye movements. During saccadic eye movements, sensitivity is reduced selectively for low-spatial frequency luminance stimuli and largely unaffected for high-spatial frequency luminance and chromatic stimuli (Nature 371 (1994), 511-513). During smooth pursuit eye movements, sensitivity for low-spatial frequency luminance stimuli is moderately reduced while sensitivity for chromatic and high-spatial frequency luminance stimuli is even increased (Nature Neuroscience, 11 (2008), 1211-1216). Since these effects are at least partly of different polarity, we investigated the combined effects of saccades and smooth pursuit on visual sensitivity. For the time course of chromatic sensitivity, we found that detection rates increased slightly around pursuit onset. During saccades to static and moving targets, detection rates dropped briefly before the saccade and reached a minimum at saccade onset. This reduction of chromatic sensitivity was present whenever a saccade was executed and it was not modified by subsequent pursuit. We also measured contrast sensitivity for flashed high- and low-spatial frequency luminance and chromatic stimuli during saccades and pursuit. During saccades, the reduction of contrast sensitivity was strongest for low-spatial frequency luminance stimuli (about 90%). However, a significant reduction was also present for chromatic stimuli (about 58%). Chromatic sensitivity was increased during smooth pursuit (about 12%). These results suggest that the modulation of visual sensitivity during saccades and smooth pursuit is more complex than previously assumed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. [Regulatory Mechanisms of PD-L1 Expression and Its Role in Immune Evasion].

    Science.gov (United States)

    Kataoka, Keisuke

    2017-11-01

    Immune checkpoint blockade therapy using anti-PD-1 or anti-PD-L1 antibodies can unleash anti-tumor immunity and induce durable remission in a variety ofhuman cancers. However, the regulatory mechanisms of PD-L1 expression mediating immune evasion ofcancer cells have not been fully elucidated, including the genetic alterations causing PD-L1 overexpression. Recently, we have reported a novel genetic mechanism ofimmune evasion associated with structural variations(SVs)disrupting the 3'-untranslated region(UTR)ofthe PD-L1 gene in various malignancies, such as aggressive lymphomas and gastrointestinal cancers. Despite a heterogenous nature ofthese SVs, they are closely associated with a marked upregulation of PD-L1 expression, which augments tumor growth and escape from anti-tumor immunity. Here we present an overview of the regulatory mechanisms of PD-L1 expression in cancer cells, highlighting the genetic mechanisms of PD-L1 constitutive activation, with specific focus on PD-L1 3'-UTR disruption.

  15. Convex games versus clan games

    NARCIS (Netherlands)

    Brânzei, R.; Dimitrov, D.A.; Tijs, S.H.

    2008-01-01

    In this paper we provide characterizations of convex games and total clan games by using properties of their corresponding marginal games. We show that a "dualize and restrict" procedure transforms total clan games with zero worth for the clan into monotonic convex games. Furthermore, each monotonic

  16. Convex Games versus Clan Games

    NARCIS (Netherlands)

    Brânzei, R.; Dimitrov, D.A.; Tijs, S.H.

    2006-01-01

    In this paper we provide characterizations of convex games and total clan games by using properties of their corresponding marginal games.We show that a "dualize and restrict" procedure transforms total clan games with zero worth for the clan into monotonic convex games.Furthermore, each monotonic

  17. Game on! : Evaluation malaria games

    NARCIS (Netherlands)

    Rob Willems

    2014-01-01

    The goal of GameOn! is to develop a serious video game. The object: to develop a serious game that aims to change behavior through awareness. The setup A multidisciplinary group which unites expertise from didactic and game production backgrounds produces an educational game for an international

  18. Sparsely-Packetized Predictive Control by Orthogonal Matching Pursuit

    DEFF Research Database (Denmark)

    Nagahara, Masaaki; Quevedo, Daniel; Østergaard, Jan

    2012-01-01

    We study packetized predictive control, known to be robust against packet dropouts in networked systems. To obtain sparse packets for rate-limited networks, we design control packets via an ℓ0 optimization, which can be eectively solved by orthogonal matching pursuit. Our formulation ensures...

  19. Narcissism and the Pursuit of Status.

    Science.gov (United States)

    Zeigler-Hill, Virgil; Vrabel, Jennifer K; McCabe, Gillian A; Cosby, Cheryl A; Traeder, Caitlin K; Hobbs, Kelsey A; Southard, Ashton C

    2018-04-10

    The purpose of the present studies was to examine the connections that narcissistic admiration and narcissistic rivalry had with various aspects of status. Study 1 examined the associations that narcissism had with the motivation to seek status in a sample of 1,219 community members. Study 2 examined whether narcissism interacted with the status seeking motive to predict how individuals pursued status in a sample of 760 community members and college students. Study 3 used a daily diary approach to examine whether narcissism moderated the associations that daily perceptions of status and affiliation had with state self-esteem in 356 college students. Our results revealed that narcissistic admiration and narcissistic rivalry were somewhat similar in their desire for status but had divergent associations with other aspects of status (e.g., strategies employed to attain status, perceptions of status, reactions to perceived status). The results of the present studies suggest that narcissistic admiration is associated with an agentic orientation to the pursuit of status, whereas narcissistic rivalry is associated with an antagonistic orientation to the pursuit of status. Discussion focuses on the implications of these results for our understanding of the connections between narcissism and status. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

  20. Which Is More Efficient in Fighting Tax Evasion: The Carrot or the Stick? A Cross-Country Comparison around the World

    OpenAIRE

    Bãtrâncea Larissa-Magareta; Bãtrâncea Ioan; Nichita Ramona-Anca

    2012-01-01

    Regardless of the economic development status, type of government or citizens’ trust level in tax authorities, tax evasion is a ubiquitous phenomenon across societies and a proof that people tend to display the same behavior all around the world. As tax evasion hinders economic growth and affects the provision of high quality public goods, tax authorities try to mitigate taxpayers’ tendency of dodging taxes by implementing either deterrence-based or reward-based strategies. The present paper ...