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Sample records for stochastic switching games

  1. Stochastic games.

    PubMed

    Solan, Eilon; Vieille, Nicolas

    2015-11-10

    In 1953, Lloyd Shapley contributed his paper "Stochastic games" to PNAS. In this paper, he defined the model of stochastic games, which were the first general dynamic model of a game to be defined, and proved that it admits a stationary equilibrium. In this Perspective, we summarize the historical context and the impact of Shapley's contribution. PMID:26556883

  2. Stochastic Differential Games with Asymmetric Information

    SciTech Connect

    Cardaliaguet, Pierre Rainer, Catherine

    2009-02-15

    We investigate a two-player zero-sum stochastic differential game in which the players have an asymmetric information on the random payoff. We prove that the game has a value and characterize this value in terms of dual viscosity solutions of some second order Hamilton-Jacobi equation.

  3. Stochastic Games with Average Payoff Criterion

    SciTech Connect

    Ghosh, M. K.; Bagchi, A.

    1998-11-15

    We study two-person stochastic games on a Polish state and compact action spaces and with average payoff criterion under a certain ergodicity condition. For the zero-sum game we establish the existence of a value and stationary optimal strategies for both players. For the nonzero-sum case the existence of Nash equilibrium in stationary strategies is established under certain separability conditions.

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

    SciTech Connect

    Cardaliaguet, P.; Rainer, C.

    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)

  5. Parity and ruin in a stochastic game

    NASA Astrophysics Data System (ADS)

    Ben-Naim, E.; Krapivsky, P. L.

    2002-02-01

    We study an elementary two-player card game where in each round players compare cards and the holder of the card with the smaller value wins. Using the rate equations approach, we treat the stochastic version of the game in which cards are drawn randomly. We obtain an exact solution for arbitrary initial conditions. In general, the game approaches a steady state where the card value densities of the two players are proportional to each other. The leading small value behavior of the initial densities determines the corresponding proportionality constant, while the next correction governs the asymptotic time dependence. The relaxation toward the steady state exhibits a rich behavior, e.g., it may be algebraically slow or exponentially fast. Moreover, in ruin situations where one player eventually wins all cards, the game may even end in a finite time.

  6. Stochastic game dynamics under demographic fluctuations.

    PubMed

    Huang, Weini; Hauert, Christoph; Traulsen, Arne

    2015-07-21

    Frequency-dependent selection and demographic fluctuations play important roles in evolutionary and ecological processes. Under frequency-dependent selection, the average fitness of the population may increase or decrease based on interactions between individuals within the population. This should be reflected in fluctuations of the population size even in constant environments. Here, we propose a stochastic model that naturally combines these two evolutionary ingredients by assuming frequency-dependent competition between different types in an individual-based model. In contrast to previous game theoretic models, the carrying capacity of the population, and thus the population size, is determined by pairwise competition of individuals mediated by evolutionary games and demographic stochasticity. In the limit of infinite population size, the averaged stochastic dynamics is captured by deterministic competitive Lotka-Volterra equations. In small populations, demographic stochasticity may instead lead to the extinction of the entire population. Because the population size is driven by fitness in evolutionary games, a population of cooperators is less prone to go extinct than a population of defectors, whereas in the usual systems of fixed size the population would thrive regardless of its average payoff. PMID:26150518

  7. Switch dynamics for stochastic model of genetic toggle switch

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Zhu, Ya-nan; Shen, Jianwei; Su, Jianbin

    2014-12-01

    Recently, more and more biological experiments have indicated that noise plays an important role in bistable systems, such as the case of the bimodal population distribution in the genetic toggle switch. In this paper, we further verify that noises in degradation rates can indeed induce switching in the genetic toggle switch. Meanwhile, we apply the theory of mean first passage time (MFPT) in high dimensional system to the above stochastic model. According to our assumption, the high order finite difference method is used to compute the MFPT (that the average time switching from one steady state to the other) and we find that the relationship between the MFPT and noise intensity is negative correlation. The result is also verified through another numerical simulation method.

  8. Stochastic Switching of Cell Fate in Microbes.

    PubMed

    Norman, Thomas M; Lord, Nathan D; Paulsson, Johan; Losick, Richard

    2015-10-15

    Microbes transiently differentiate into distinct, specialized cell types to generate functional diversity and cope with changing environmental conditions. Though alternate programs often entail radically different physiological and morphological states, recent single-cell studies have revealed that these crucial decisions are often left to chance. In these cases, the underlying genetic circuits leverage the intrinsic stochasticity of intracellular chemistry to drive transition between states. Understanding how these circuits transform transient gene expression fluctuations into lasting phenotypic programs will require a combination of quantitative modeling and extensive, time-resolved observation of switching events in single cells. In this article, we survey microbial cell fate decisions demonstrated to involve a random element, describe theoretical frameworks for understanding stochastic switching between states, and highlight recent advances in microfluidics that will enable characterization of key dynamic features of these circuits. PMID:26332088

  9. Stochastic Frontier Estimation of Efficient Learning in Video Games

    ERIC Educational Resources Information Center

    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

  10. Stochastic Stability in Internet Router Congestion Games

    NASA Astrophysics Data System (ADS)

    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.

  11. Two Different Approaches to Nonzero-Sum Stochastic Differential Games

    SciTech Connect

    Rainer, Catherine

    2007-06-15

    We make the link between two approaches to Nash equilibria for nonzero-sum stochastic differential games: the first one using backward stochastic differential equations and the second one using strategies with delay. We prove that, when both exist, the two notions of Nash equilibria coincide.

  12. Stochastic Frontier Estimation of Efficient Learning in Video Games

    ERIC Educational Resources Information Center

    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…

  13. Stochastic gene expression in switching environments.

    PubMed

    Gander, Martin J; Mazza, Christian; Rummler, Hansklaus

    2007-08-01

    Organisms are known to adapt to regularly varying environments. However, in most cases, the fluctuations of the environment are irregular and stochastic, alternating between favorable and unfavorable regimes, so that cells must cope with an uncertain future. A possible response is population diversification. We assume here that the cell population is divided into two groups, corresponding to two phenotypes, having distinct growth rates, and that cells can switch randomly their phenotypes. In static environments, the net growth rate is maximized when the population is homogeneously composed of cells having the largest growth rate. In random environments, growth rates fluctuate and observations reveal that sometimes heterogeneous populations have a larger net growth rate than homogeneous ones, a fact illustrated recently through Monte-Carlo simulations based on a birth and migration process in a random environment. We study this process mathematically by focusing on the proportion f(t) of cells having the largest growth rate at time t, and give explicitly the related steady state distribution pi. We also prove the convergence of empirical averages along trajectories to the first moment E(pi) (f), and provide efficient numerical methods for computing E(pi) (f). PMID:17380334

  14. Stochastic switching as a survival strategy in fluctuating environments.

    PubMed

    Acar, Murat; Mettetal, Jerome T; van Oudenaarden, Alexander

    2008-04-01

    A classic problem in population and evolutionary biology is to understand how a population optimizes its fitness in fluctuating environments. A population might enhance its fitness by allowing individual cells to stochastically transition among multiple phenotypes, thus ensuring that some cells are always prepared for an unforeseen environmental fluctuation. Here we experimentally explore how switching affects population growth by using the galactose utilization network of Saccharomyces cerevisiae. We engineered a strain that randomly transitions between two phenotypes as a result of stochastic gene expression. Each phenotype was designed to confer a growth advantage over the other phenotype in a certain environment. When we compared the growth of two populations with different switching rates, we found that fast-switching populations outgrow slow switchers when the environment fluctuates rapidly, whereas slow-switching phenotypes outgrow fast switchers when the environment changes rarely. These results suggest that cells may tune inter-phenotype switching rates to the frequency of environmental changes. PMID:18362885

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Stochastic Heterogeneous Interaction Promotes Cooperation in Spatial Prisoner's Dilemma Game

    PubMed Central

    Zhu, Ping; Wei, Guiyi

    2014-01-01

    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. PMID:24759921

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

    PubMed

    Zhu, Ping; Wei, Guiyi

    2014-01-01

    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. PMID:24759921

  18. Self-Consistent Proteomic Field Theory of Stochastic Gene Switches

    NASA Astrophysics Data System (ADS)

    Walczak, Aleksandra M.; Sasai, Masaki; Wolynes, Peter G.

    2005-03-01

    The need for a computationally efficient treatment of genetic networks and cascades, which, while acknowledging their stochastic character, at the same time allows us to gain a better and deeper understanding of the global attractor structure is widely recognized. Even treating the building blocks of these systems, genetic switches, generally requires some approximations. We propose a powerful generically applicable method, a self-consistent proteomic field approximation in which the mean influence of the proteomic cloud created by one gene on the action of another is computed self-consistently [1]. The stochastic nature of protein synthesis and degradation, and DNA binding events are treated stochastically and on equal footing. For a large class of problems, in which the output proteins of one gene influence other genes, the probability distributions may be determined exactly without any further assumptions within the self-consistent proteomic field approximation. We compare the results for various versions of a toggle switch composed of two mutually repressing genes to solutions of deterministic rate equations and find that when proteins are produced in bursts, the deterministic approach can fail dramatically.1. Walczak, A.M., Sasai, M., Wolynes P.G., Self Consistent Proteomic Field Theory of Stochastic Gene Switches, to be published in Biophysical Journal

  19. Stability of stochastic nonlinear switched systems with average dwell time

    NASA Astrophysics Data System (ADS)

    Wu, Xiaotai; Yan, Litan; Zhang, Wenbing; Tang, Yang

    2012-03-01

    This paper concerns the stability of nonlinear stochastic switched systems with delay. By using the Razumikhin method and the average dwell time approach, some sufficient criteria of stability are derived. It is shown that when the Lyapunov-like functions are decreasing in all active subsystems, the switched system is pth-moment exponentially stable. Moreover, it is also shown that under some conditions the system can be pth-moment stable and global asymptotically stable, where the Lyapunov-like functions are increasing on some intervals. The effectiveness of the proposed results is illustrated by two examples.

  20. Partial synchronization in stochastic dynamical networks with switching communication channels

    NASA Astrophysics Data System (ADS)

    Huang, Chi; Ho, Daniel W. C.; Lu, Jianquan; Kurths, Jrgen

    2012-06-01

    In this paper, the partial synchronization problem of stochastic dynamical networks (SDNs) is investigated. Unlike the existing models, the SDN considered in this paper suffers from a class of communication constraintonly part of nodes' states can be transmitted. Thus, less nodes' states can be used to synchronize the SDN, which makes the analysis of the synchronization problem much harder. A set of channel matrices are introduced to reflect such kind of constraint. Furthermore, due to unpredictable environmental changes, the channel matrices can switch among some communication modes. The switching considered here is governed by a Markov process. To overcome the difficulty, a regrouping method is employed to derive our main results. The obtained conditions guarantee that partial synchronization can be achieved for SDNs under switching communication constraint. Finally, numerical examples are given to illustrate the effectiveness of the theoretical results and how the communication constraint influences synchronization result.

  1. A stochastic transcriptional switch model for single cell imaging data

    PubMed Central

    Hey, Kirsty L.; Momiji, Hiroshi; Featherstone, Karen; Davis, Julian R.E.; White, Michael R.H.; Rand, David A.; Finkenstädt, Bärbel

    2015-01-01

    Gene expression is made up of inherently stochastic processes within single cells and can be modeled through stochastic reaction networks (SRNs). In particular, SRNs capture the features of intrinsic variability arising from intracellular biochemical processes. We extend current models for gene expression to allow the transcriptional process within an SRN to follow a random step or switch function which may be estimated using reversible jump Markov chain Monte Carlo (MCMC). This stochastic switch model provides a generic framework to capture many different dynamic features observed in single cell gene expression. Inference for such SRNs is challenging due to the intractability of the transition densities. We derive a model-specific birth–death approximation and study its use for inference in comparison with the linear noise approximation where both approximations are considered within the unifying framework of state-space models. The methodology is applied to synthetic as well as experimental single cell imaging data measuring expression of the human prolactin gene in pituitary cells. PMID:25819987

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

    SciTech Connect

    Hosking, John Joseph Absalom

    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.

  3. Stability analysis of switched stochastic neural networks with time-varying delays.

    PubMed

    Wu, Xiaotai; Tang, Yang; Zhang, Wenbing

    2014-03-01

    This paper is concerned with the global exponential stability of switched stochastic neural networks with time-varying delays. Firstly, the stability of switched stochastic delayed neural networks with stable subsystems is investigated by utilizing the mathematical induction method, the piecewise Lyapunov function and the average dwell time approach. Secondly, by utilizing the extended comparison principle from impulsive systems, the stability of stochastic switched delayed neural networks with both stable and unstable subsystems is analyzed and several easy to verify conditions are derived to ensure the exponential mean square stability of switched delayed neural networks with stochastic disturbances. The effectiveness of the proposed results is illustrated by two simulation examples. PMID:24365535

  4. Adaptive role switching promotes fairness in networked ultimatum game

    PubMed Central

    Wu, Te; Fu, Feng; Zhang, Yanling; Wang, Long

    2013-01-01

    In recent years, mechanisms favoring fair split in the ultimatum game have attracted growing interests because of its practical implications for international bargains. In this game, two players are randomly assigned two different roles respectively to split an offer: the proposer suggests how to split and the responder decides whether or not to accept it. Only when both agree is the offer successfully split; otherwise both get nothing. It is of importance and interest to break the symmetry in role assignment especially when the game is repeatedly played in a heterogeneous population. Here we consider an adaptive role assignment: whenever the split fails, the two players switch their roles probabilistically. The results show that this simple feedback mechanism proves much more effective at promoting fairness than other alternatives (where, for example, the role assignment is based on the number of neighbors). PMID:23528986

  5. Switching of bound vector solitons for the coupled nonlinear Schroedinger equations with nonhomogenously stochastic perturbations

    SciTech Connect

    Sun Zhiyuan; Yu Xin; Liu Ying; Gao Yitian

    2012-12-15

    We investigate the dynamics of the bound vector solitons (BVSs) for the coupled nonlinear Schroedinger equations with the nonhomogenously stochastic perturbations added on their dispersion terms. Soliton switching (besides soliton breakup) can be observed between the two components of the BVSs. Rate of the maximum switched energy (absolute values) within the fixed propagation distance (about 10 periods of the BVSs) enhances in the sense of statistics when the amplitudes of stochastic perturbations increase. Additionally, it is revealed that the BVSs with enhanced coherence are more robust against the perturbations with nonhomogenous stochasticity. Diagram describing the approximate borders of the splitting and non-splitting areas is also given. Our results might be helpful in dynamics of the BVSs with stochastic noises in nonlinear optical fibers or with stochastic quantum fluctuations in Bose-Einstein condensates.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Robust stability of stochastic delayed additive neural networks with Markovian switching.

    PubMed

    Huang, He; Ho, Daniel W C; Qu, Yuzhong

    2007-09-01

    This paper is concerned with the problem of robust stability for stochastic interval delayed additive neural networks (SIDANN) with Markovian switching. The time delay is assumed to be time-varying. In such neural networks, the features of stochastic systems, interval systems, time-varying delay systems and Markovian switching are taken into account. The mathematical model of this kind of neural networks is first proposed. Secondly, the global exponential stability in the mean square is studied for the SIDANN with Markovian switching. Based on the Lyapunov method, several stability conditions are presented, which can be expressed in terms of linear matrix inequalities. As a subsequent result, the stochastic interval additive neural networks with time-varying delay are also discussed. A sufficient condition is given to determine its stability. Finally, two simulation examples are provided to illustrate the effectiveness of the results developed. PMID:17714914

  8. Accelerated Iterations for Finding the Soft-constrained Stochastic Nash Games Equilibrium

    NASA Astrophysics Data System (ADS)

    Ivanov, I. G.; Rusinova, R. I.; Lomev, B. M.

    2010-11-01

    In this paper, the stochastic Nash games for weakly coupled large-scale systems with state-dependent noise are considered. The considered stochastic algebraic Riccati equations is quite different from the existing results in the sense that the equations have the additional linear term. The numerical algorithm based on Lyapunov iterations for solving the set of cross-coupled stochastic algebraic Riccati equations is derived by Mukaidani (American Control Conference, June 2008, USA 4232-4237). We modify this method and derive new iterations based on the solution of linear matrix equations with linear rate of convergence. We carry out numerical experiments to illustrate the effectiveness of the considered iterations.

  9. The stochastic evolutionary game for a population of biological networks under natural selection.

    PubMed

    Chen, Bor-Sen; Ho, Shih-Ju

    2014-01-01

    In this study, a population of evolutionary biological networks is described by a stochastic dynamic system with intrinsic random parameter fluctuations due to genetic variations and external disturbances caused by environmental changes in the evolutionary process. Since information on environmental changes is unavailable and their occurrence is unpredictable, they can be considered as a game player with the potential to destroy phenotypic stability. The biological network needs to develop an evolutionary strategy to improve phenotypic stability as much as possible, so it can be considered as another game player in the evolutionary process, ie, a stochastic Nash game of minimizing the maximum network evolution level caused by the worst environmental disturbances. Based on the nonlinear stochastic evolutionary game strategy, we find that some genetic variations can be used in natural selection to construct negative feedback loops, efficiently improving network robustness. This provides larger genetic robustness as a buffer against neutral genetic variations, as well as larger environmental robustness to resist environmental disturbances and maintain a network phenotypic traits in the evolutionary process. In this situation, the robust phenotypic traits of stochastic biological networks can be more frequently selected by natural selection in evolution. However, if the harbored neutral genetic variations are accumulated to a sufficiently large degree, and environmental disturbances are strong enough that the network robustness can no longer confer enough genetic robustness and environmental robustness, then the phenotype robustness might break down. In this case, a network phenotypic trait may be pushed from one equilibrium point to another, changing the phenotypic trait and starting a new phase of network evolution through the hidden neutral genetic variations harbored in network robustness by adaptive evolution. Further, the proposed evolutionary game is extended to an n-tuple evolutionary game of stochastic biological networks with m players (competitive populations) and k environmental dynamics. PMID:24558296

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

    NASA Astrophysics Data System (ADS)

    Si, Tieyan

    2012-11-01

    An optical model of classical photons propagating through array of many beam splitters is developed to give a physical analogy of Parrondo's game and Parrondo-Harmer-Abbott game. We showed both the two games are reasonable game without so-called game paradox and they are essentially the same. We designed the games with long-term memory on loop lattice and history-entangled game. The strong correlation between nearest two rounds of game can make the combination of two losing game win, lose or oscillate between win and loss. The periodic potential in Brownian ratchet is analogous to a long chain of beam splitters. The coupling between two neighboring potential wells is equivalent to two coupled beam splitters. This correspondence may help us to understand the anomalous motion of exceptional Brownian particles moving in the opposite direction to the majority. We designed the capital wave for a game by introducing correlations into independent capitals instead of sub-games. Playing entangled quantum states in many coupled classical games obey the same rules for manipulating quantum states in many body physics.

  11. pth Moment stability of impulsive stochastic delay differential systems with Markovian switching

    NASA Astrophysics Data System (ADS)

    Wu, Xiaotai; Zhang, Wenbing; Tang, Yang

    2013-07-01

    This paper is concerned with the pth moment stability of impulsive stochastic delay differential systems with Markovian switching. By using the Razumikhin-type method, some stability criteria are obtained, which can loosen the constraints of the existing results and thus reduce the conservativeness. Two examples are presented to demonstrate the usefulness of the proposed results.

  12. Sufficient Stochastic Maximum Principle in a Regime-Switching Diffusion Model

    SciTech Connect

    Donnelly, Catherine

    2011-10-15

    We prove a sufficient stochastic maximum principle for the optimal control of a regime-switching diffusion model. We show the connection to dynamic programming and we apply the result to a quadratic loss minimization problem, which can be used to solve a mean-variance portfolio selection problem.

  13. Stochastic gene expression modeling with Hill function for switch-like gene responses.

    PubMed

    Kim, Haseong; Gelenbe, Erol

    2012-01-01

    Gene expression models play a key role to understand the mechanisms of gene regulation whose aspects are grade and switch-like responses. Though many stochastic approaches attempt to explain the gene expression mechanisms, the Gillespie algorithm which is commonly used to simulate the stochastic models requires additional gene cascade to explain the switch-like behaviors of gene responses. In this study, we propose a stochastic gene expression model describing the switch-like behaviors of a gene by employing Hill functions to the conventional Gillespie algorithm. We assume eight processes of gene expression and their biologically appropriate reaction rates are estimated based on published literatures. We observed that the state of the system of the toggled switch model is rarely changed since the Hill function prevents the activation of involved proteins when their concentrations stay below a criterion. In ScbA-ScbR system, which can control the antibiotic metabolite production of microorganisms, our modified Gillespie algorithm successfully describes the switch-like behaviors of gene responses and oscillatory expressions which are consistent with the published experimental study. PMID:22144531

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

    PubMed Central

    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. PMID:26402322

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

    PubMed

    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. PMID:26402322

  16. Impact of deterministic and stochastic updates on network reciprocity in the prisoner's dilemma game

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun

    2014-08-01

    In 2 2 prisoner's dilemma games, network reciprocity is one mechanism for adding social viscosity, which leads to cooperative equilibrium. This study introduced an intriguing framework for the strategy update rule that allows any combination of a purely deterministic method, imitation max (IM), and a purely probabilistic one, pairwise Fermi (Fermi-PW). A series of simulations covering the whole range from IM to Fermi-PW reveals that, as a general tendency, the larger fractions of stochastic updating reduce network reciprocity, so long as the underlying lattice contains no noise in the degree of distribution. However, a small amount of stochastic flavor added to an otherwise perfectly deterministic update rule was actually found to enhance network reciprocity. This occurs because a subtle stochastic effect in the update rule improves the evolutionary trail in games having more stag-hunt-type dilemmas, although the same stochastic effect degenerates evolutionary trails in games having more chicken-type dilemmas. We explain these effects by dividing evolutionary trails into the enduring and expanding periods defined by Shigaki et al. [Phys. Rev. E 86, 031141 (2012), 10.1103/PhysRevE.86.031141].

  17. PULSAR STATE SWITCHING FROM MARKOV TRANSITIONS AND STOCHASTIC RESONANCE

    SciTech Connect

    Cordes, J. M.

    2013-09-20

    Markov processes are shown to be consistent with metastable states seen in pulsar phenomena, including intensity nulling, pulse-shape mode changes, subpulse drift rates, spin-down rates, and X-ray emission, based on the typically broad and monotonic distributions of state lifetimes. Markovianity implies a nonlinear magnetospheric system in which state changes occur stochastically, corresponding to transitions between local minima in an effective potential. State durations (though not transition times) are thus largely decoupled from the characteristic timescales of various magnetospheric processes. Dyadic states are common but some objects show at least four states with some transitions forbidden. Another case is the long-term intermittent pulsar B1931+24 that has binary radio-emission and torque states with wide, but non-monotonic duration distributions. It also shows a quasi-period of 38 ± 5 days in a 13 yr time sequence, suggesting stochastic resonance in a Markov system with a forcing function that could be strictly periodic or quasi-periodic. Nonlinear phenomena are associated with time-dependent activity in the acceleration region near each magnetic polar cap. The polar-cap diode is altered by feedback from the outer magnetosphere and by return currents from the equatorial region outside the light cylinder that may also cause the neutron star to episodically charge and discharge. Orbital perturbations of a disk or current sheet provide a natural periodicity for the forcing function in the stochastic-resonance interpretation of B1931+24. Disk dynamics may introduce additional timescales in observed phenomena. Future work can test the Markov interpretation, identify which pulsar types have a propensity for state changes, and clarify the role of selection effects.

  18. An Element of Determinism in a Stochastic Flagellar Motor Switch

    PubMed Central

    Xie, Li; Altindal, Tuba; Wu, Xiao-Lun

    2015-01-01

    Marine bacterium Vibrio alginolyticus uses a single polar flagellum to navigate in an aqueous environment. Similar to Escherichia coli cells, the polar flagellar motor has two states; when the motor is counter-clockwise, the cell swims forward and when the motor is clockwise, the cell swims backward. V. alginolyticus also incorporates a direction randomization step at the start of the forward swimming interval by flicking its flagellum. To gain an understanding on how the polar flagellar motor switch is regulated, distributions of the forward Δf and backward Δb intervals are investigated herein. We found that the steady-state probability density functions, P(Δf) and P(Δb), of freely swimming bacteria are strongly peaked at a finite time, suggesting that the motor switch is not Poissonian. The short-time inhibition is sufficiently strong and long lasting, i.e., several hundred milliseconds for both intervals, which is readily observed and characterized. Treating motor reversal dynamics as a first-passage problem, which results from conformation fluctuations of the motor switch, we calculated P(Δf) and P(Δb) and found good agreement with the measurements. PMID:26554590

  19. Theory of superconductive-resistive switching in nanowires due to heating by stochastic phase slips

    NASA Astrophysics Data System (ADS)

    Shah, Nayana; Pekker, David; Goldbart, Paul

    2008-03-01

    We study the stochastic dynamics of superconductive-to-resistive switching in hysteretic current-biased superconducting nanowires undergoing phase-slip fluctuations. We assume that the hysteresis is thermal in nature, and postulate that the mechanism for the switching is thermal runaway, i.e. rare sequences of stochastic phase slips, closely spaced in time, that heat the nanowire. Thus, via the master-equation formalism, we obtain the distribution of currents at which switching occurs. If switching were caused by single, thermally-activated phase-slip events then this distribution would narrow as the temperature is reduced. However, at higher temperatures we find that several phase-slip events are typically necessary for inducing switching, and this results in an initial broadening of the distribution upon cooling. Quite generally, we predict that at low temperatures thermal runaway is caused by a single phase-slip event. Thus, measurements of switching-current distributions in this regime are a direct probe of this basic collective process. In particular, this regime could yield observations of individual quantum phase slips in nanowires.

  20. Confinement and diffusion modulate bistability and stochastic switching in a reaction network with positive feedback

    NASA Astrophysics Data System (ADS)

    Mlynarczyk, Paul J.; Pullen, Robert H.; Abel, Steven M.

    2016-01-01

    Positive feedback is a common feature in signal transduction networks and can lead to phenomena such as bistability and signal propagation by domain growth. Physical features of the cellular environment, such as spatial confinement and the mobility of proteins, play important but inadequately understood roles in shaping the behavior of signaling networks. Here, we use stochastic, spatially resolved kinetic Monte Carlo simulations to explore a positive feedback network as a function of system size, system shape, and mobility of molecules. We show that these physical properties can markedly alter characteristics of bistability and stochastic switching when compared with well-mixed simulations. Notably, systems of equal volume but different shapes can exhibit qualitatively different behaviors under otherwise identical conditions. We show that stochastic switching to a state maintained by positive feedback occurs by cluster formation and growth. Additionally, the frequency at which switching occurs depends nontrivially on the diffusion coefficient, which can promote or suppress switching relative to the well-mixed limit. Taken together, the results provide a framework for understanding how confinement and protein mobility influence emergent features of the positive feedback network by modulating molecular concentrations, diffusion-influenced rate parameters, and spatiotemporal correlations between molecules.

  1. Confinement and diffusion modulate bistability and stochastic switching in a reaction network with positive feedback.

    PubMed

    Mlynarczyk, Paul J; Pullen, Robert H; Abel, Steven M

    2016-01-01

    Positive feedback is a common feature in signal transduction networks and can lead to phenomena such as bistability and signal propagation by domain growth. Physical features of the cellular environment, such as spatial confinement and the mobility of proteins, play important but inadequately understood roles in shaping the behavior of signaling networks. Here, we use stochastic, spatially resolved kinetic Monte Carlo simulations to explore a positive feedback network as a function of system size, system shape, and mobility of molecules. We show that these physical properties can markedly alter characteristics of bistability and stochastic switching when compared with well-mixed simulations. Notably, systems of equal volume but different shapes can exhibit qualitatively different behaviors under otherwise identical conditions. We show that stochastic switching to a state maintained by positive feedback occurs by cluster formation and growth. Additionally, the frequency at which switching occurs depends nontrivially on the diffusion coefficient, which can promote or suppress switching relative to the well-mixed limit. Taken together, the results provide a framework for understanding how confinement and protein mobility influence emergent features of the positive feedback network by modulating molecular concentrations, diffusion-influenced rate parameters, and spatiotemporal correlations between molecules. PMID:26747820

  2. DOOM'd to Switch: Superior Cognitive Flexibility in Players of First Person Shooter Games.

    PubMed

    Colzato, Lorenza S; van Leeuwen, Pieter J A; van den Wildenberg, Wery P M; Hommel, Bernhard

    2010-01-01

    The interest in the influence of videogame experience on our daily life is constantly growing. "First Person Shooter" (FPS) games require players to develop a flexible mindset to rapidly react to fast moving visual and auditory stimuli, and to switch back and forth between different subtasks. This study investigated whether and to which degree experience with such videogames generalizes to other cognitive-control tasks. Video-game players (VGPs) and individuals with little to no videogame experience (NVGPs) performed on a task switching paradigm that provides a relatively well-established diagnostic measure of cognitive flexibility. As predicted, VGPs showed smaller switching costs (i.e., greater cognitive flexibility) than NVGPs. Our findings support the idea that playing FPS games promotes cognitive flexibility. PMID:21833191

  3. Nash Games for Weakly-Coupled Large-Scale Markovian Jump Stochastic Systems

    NASA Astrophysics Data System (ADS)

    Sagara, Muneomi; Mukaidani, Hiroaki

    In this paper, the stochastic Nash games for stochastic Markov jump systems are investigated. First, the Nash equilibrium is defined and the existence conditions are formulated. In particular, necessary and sufficient conditions for the existence of two cross-coupled stochastic algebraic Riccati equations (CSAREs) are developed. Moreover, in order to obtain the required solutions, a numerical algorithm that is based on the Newton's method is proposed. As an important implication, weakly-coupled large-scale systems are also adopted. After establishing the asymptotic structure of the solutions for the CSAREs, the quadratic convergence result that is based on the Newton's method is shown. Finally, a numerical example is given to demonstrate the availability of the proposed method.

  4. Control of Stochastic and Induced Switching in Biophysical Networks

    NASA Astrophysics Data System (ADS)

    Wells, Daniel K.; Kath, William L.; Motter, Adilson E.

    2015-07-01

    Noise caused by fluctuations at the molecular level is a fundamental part of intracellular processes. While the response of biological systems to noise has been studied extensively, there has been limited understanding of how to exploit it to induce a desired cell state. Here we present a scalable, quantitative method based on the Freidlin-Wentzell action to predict and control noise-induced switching between different states in genetic networks that, conveniently, can also control transitions between stable states in the absence of noise. We apply this methodology to models of cell differentiation and show how predicted manipulations of tunable factors can induce lineage changes, and further utilize it to identify new candidate strategies for cancer therapy in a cell death pathway model. This framework offers a systems approach to identifying the key factors for rationally manipulating biophysical dynamics, and should also find use in controlling other classes of noisy complex networks.

  5. Control of Stochastic and Induced Switching in Biophysical Networks

    PubMed Central

    Wells, Daniel K.; Kath, William L.; Motter, Adilson E.

    2015-01-01

    Noise caused by fluctuations at the molecular level is a fundamental part of intracellular processes. While the response of biological systems to noise has been studied extensively, there has been limited understanding of how to exploit it to induce a desired cell state. Here we present a scalable, quantitative method based on the Freidlin-Wentzell action to predict and control noise-induced switching between different states in genetic networks that, conveniently, can also control transitions between stable states in the absence of noise. We apply this methodology to models of cell differentiation and show how predicted manipulations of tunable factors can induce lineage changes, and further utilize it to identify new candidate strategies for cancer therapy in a cell death pathway model. This framework offers a systems approach to identifying the key factors for rationally manipulating biophysical dynamics, and should also find use in controlling other classes of noisy complex networks. PMID:26451275

  6. Non-stochastic switching and emergence of magnetic vortices in artificial quasicrystal spin ice

    NASA Astrophysics Data System (ADS)

    Bhat, V. S.; Farmer, B.; Smith, N.; Teipel, E.; Woods, J.; Sklenar, J.; Ketterson, J. B.; Hastings, J. T.; De Long, L. E.

    2014-08-01

    Previous studies of artificial spin ice have been largely restricted to periodic dot lattices. Ferromagnetic switching of segments in an applied magnetic field is stochastic in periodic spin ice systems, which makes emergent phenomena, such as the formation of vortex loops, hard to control or predict. We fabricated finite, aperiodic Penrose P2 tilings as antidot lattices with fivefold rotational symmetry in permalloy thin films. Measurements of the field dependence of the static magnetization reveal reproducible knee anomalies whose number and form are temperature dependent, which suggests they mark cooperative rearrangements of the tiling magnetic texture. Our micromagnetic simulations of the P2 tiling are in good agreement with experimental magnetization data and exhibit non-stochastic magnetic switching of segments in applied field, and vortex loops that are stable over an extended field interval during magnetic reversal.

  7. Designing a stochastic genetic switch by coupling chaos and bistability

    NASA Astrophysics Data System (ADS)

    Zhao, Xiang; Ouyang, Qi; Wang, Hongli

    2015-11-01

    In stem cell differentiation, a pluripotent stem cell becomes progressively specialized and generates specific cell types through a series of epigenetic processes. How cells can precisely determine their fate in a fluctuating environment is a currently unsolved problem. In this paper, we suggest an abstract gene regulatory network to describe mathematically the differentiation phenomenon featuring stochasticity, divergent cell fates, and robustness. The network consists of three functional motifs: an upstream chaotic motif, a buffering motif of incoherent feed forward loop capable of generating a pulse, and a downstream motif which is bistable. The dynamic behavior is typically a transient chaos with fractal basin boundaries. The trajectories take transiently chaotic journeys before divergently settling down to the bistable states. The ratio of the probability that the high state is achieved to the probability that the low state is reached can maintain a constant in a population of cells with varied molecular fluctuations. The ratio can be turned up or down when proper parameters are adjusted. The model suggests a possible mechanism for the robustness against fluctuations that is prominently featured in pluripotent cell differentiations and developmental phenomena.

  8. Designing a stochastic genetic switch by coupling chaos and bistability.

    PubMed

    Zhao, Xiang; Ouyang, Qi; Wang, Hongli

    2015-11-01

    In stem cell differentiation, a pluripotent stem cell becomes progressively specialized and generates specific cell types through a series of epigenetic processes. How cells can precisely determine their fate in a fluctuating environment is a currently unsolved problem. In this paper, we suggest an abstract gene regulatory network to describe mathematically the differentiation phenomenon featuring stochasticity, divergent cell fates, and robustness. The network consists of three functional motifs: an upstream chaotic motif, a buffering motif of incoherent feed forward loop capable of generating a pulse, and a downstream motif which is bistable. The dynamic behavior is typically a transient chaos with fractal basin boundaries. The trajectories take transiently chaotic journeys before divergently settling down to the bistable states. The ratio of the probability that the high state is achieved to the probability that the low state is reached can maintain a constant in a population of cells with varied molecular fluctuations. The ratio can be turned up or down when proper parameters are adjusted. The model suggests a possible mechanism for the robustness against fluctuations that is prominently featured in pluripotent cell differentiations and developmental phenomena. PMID:26627572

  9. DNA looping increases the range of bistability in a stochastic model of the lac genetic switch

    NASA Astrophysics Data System (ADS)

    Earnest, Tyler M.; Roberts, Elijah; Assaf, Michael; Dahmen, Karin; Luthey-Schulten, Zaida

    2013-04-01

    Conditions and parameters affecting the range of bistability of the lac genetic switch in Escherichia coli are examined for a model which includes DNA looping interactions with the lac repressor and a lactose analogue. This stochastic gene-mRNA-protein model of the lac switch describes DNA looping using a third transcriptional state. We exploit the fast bursting dynamics of mRNA by combining a novel geometric burst extension with the finite state projection method. This limits the number of protein/mRNA states, allowing for an accelerated search of the model's parameter space. We evaluate how the addition of the third state changes the bistability properties of the model and find a critical region of parameter space where the phenotypic switching occurs in a range seen in single molecule fluorescence studies. Stochastic simulations show induction in the looping model is preceded by a rare complete dissociation of the loop followed by an immediate burst of mRNA rather than a slower build up of mRNA as in the two-state model. The overall effect of the looped state is to allow for faster switching times while at the same time further differentiating the uninduced and induced phenotypes. Furthermore, the kinetic parameters are consistent with free energies derived from thermodynamic studies suggesting that this minimal model of DNA looping could have a broader range of application.

  10. Stochastic or systematic? Seemingly random perceptual switching in bistable events triggered by transient unconscious cues.

    PubMed

    Ward, Emily J; Scholl, Brian J

    2015-08-01

    What we see is a function not only of incoming stimulation, but of unconscious inferences in visual processing. Among the most powerful demonstrations of this are bistable events, but what causes the percepts of such events to switch? Beyond voluntary effort and stochastic processing, we explore the ways in which ongoing dynamic percepts may switch as a function of the content of brief, unconscious, independent cues. We introduced transient disambiguating occlusion cues into the Spinning Dancer silhouette animation. The dancer is bistable in terms of depth and rotation direction, but many observers see extended rotation in the same direction, interrupted only rarely by involuntary switches. Observers failed to notice these occasional disambiguating cues, but their impact was strong and systematic: Cues typically led to seemingly stochastic perceptual switches shortly thereafter, especially when conflicting with the current percept. These results show how the content of incoming information determines and constrains online conscious perception-even when neither the content nor the brute existence of that information ever reaches awareness. Thus, just as phenomenological ease does not imply a corresponding lack of underlying effortful computation, phenomenological randomness should not be taken to imply a corresponding lack of underlying systematicity. PMID:25915074

  11. A novel adaptive switching function on fault tolerable sliding mode control for uncertain stochastic systems.

    PubMed

    Zahiripour, Seyed Ali; Jalali, Ali Akbar

    2014-09-01

    A novel switching function based on an optimization strategy for the sliding mode control (SMC) method has been provided for uncertain stochastic systems subject to actuator degradation such that the closed-loop system is globally asymptotically stable with probability one. In the previous researches the focus on sliding surface has been on proportional or proportional-integral function of states. In this research, from a degree of freedom that depends on designer choice is used to meet certain objectives. In the design of the switching function, there is a parameter which the designer can regulate for specified objectives. A sliding-mode controller is synthesized to ensure the reachability of the specified switching surface, despite actuator degradation and uncertainties. Finally, the simulation results demonstrate the effectiveness of the proposed method. PMID:24954808

  12. A role of stochastic phenotype switching in generating mosaic endothelial cell heterogeneity.

    PubMed

    Yuan, Lei; Chan, Gary C; Beeler, David; Janes, Lauren; Spokes, Katherine C; Dharaneeswaran, Harita; Mojiri, Anahita; Adams, William J; Sciuto, Tracey; Garcia-Cardea, Guillermo; Molema, Grietje; Kang, Peter M; Jahroudi, Nadia; Marsden, Philip A; Dvorak, Ann; Regan, Erzsbet Ravasz; Aird, William C

    2016-01-01

    Previous studies have shown that biological noise may drive dynamic phenotypic mosaicism in isogenic unicellular organisms. However, there is no evidence for a similar mechanism operating in metazoans. Here we show that the endothelial-restricted gene, von Willebrand factor (VWF), is expressed in a mosaic pattern in the capillaries of many vascular beds and in the aorta. In capillaries, the mosaicism is dynamically regulated, with VWF switching between ON and OFF states during the lifetime of the animal. Clonal analysis of cultured endothelial cells reveals that dynamic mosaic heterogeneity is controlled by a low-barrier, noise-sensitive bistable switch that involves random transitions in the DNA methylation status of the VWF promoter. Finally, the hearts of VWF-null mice demonstrate an abnormal endothelial phenotype as well as cardiac dysfunction. Together, these findings suggest a novel stochastic phenotype switching strategy for adaptive homoeostasis in the adult vasculature. PMID:26744078

  13. Stochastic game theory: For playing games, not just for doing theory

    PubMed Central

    Goeree, Jacob K.; Holt, Charles A.

    1999-01-01

    Recent theoretical advances have dramatically increased the relevance of game theory for predicting human behavior in interactive situations. By relaxing the classical assumptions of perfect rationality and perfect foresight, we obtain much improved explanations of initial decisions, dynamic patterns of learning and adjustment, and equilibrium steady-state distributions. PMID:10485862

  14. Stochastic switching in slow-fast systems: a large-fluctuation approach.

    PubMed

    Heckman, Christoffer R; Schwartz, Ira B

    2014-02-01

    In this paper we develop a perturbation method to predict the rate of occurrence of rare events for singularly perturbed stochastic systems using a probability density function approach. In contrast to a stochastic normal form approach, we model rare event occurrences due to large fluctuations probabilistically and employ a WKB ansatz to approximate their rate of occurrence. This results in the generation of a two-point boundary value problem that models the interaction of the state variables and the most likely noise force required to induce a rare event. The resulting equations of motion of describing the phenomenon are shown to be singularly perturbed. Vastly different time scales among the variables are leveraged to reduce the dimension and predict the dynamics on the slow manifold in a deterministic setting. The resulting constrained equations of motion may be used to directly compute an exponent that determines the probability of rare events. To verify the theory, a stochastic damped Duffing oscillator with three equilibrium points (two sinks separated by a saddle) is analyzed. The predicted switching time between states is computed using the optimal path that resides in an expanded phase space. We show that the exponential scaling of the switching rate as a function of system parameters agrees well with numerical simulations. Moreover, the dynamics of the original system and the reduced system via center manifolds are shown to agree in an exponentially scaling sense. PMID:25353557

  15. The effect of action video game experience on task-switching

    PubMed Central

    Green, C.Shawn; Sugarman, Michael A.; Medford, Katherine; Klobusicky, Elizabeth; Daphne Bavelier

    2012-01-01

    There is now a substantial body of work demonstrating that action video game experience results in enhancements in a wide variety of perceptual skills. More recently, several groups have also demonstrated improvements in abilities that are more cognitive in nature, in particular, the ability to efficiently switch between tasks. In a series of four experiments, we add to this body of work, demonstrating that the action video game player advantage is not exclusively due to an ability to map manual responses onto arbitrary buttons, but rather generalizes to vocal responses, is not restricted to tasks that are perceptual in nature (e.g. respond to a physical dimension of the stimulus such as its color), but generalizes to more cognitive tasks (e.g. is a number odd or even), and is present whether the switch requires a goal-switch or only a motor switch. Finally, a training study establishes that the relationship between the reduction in switch cost and action game playing is causal. PMID:22393270

  16. The coevolution of partner switching and strategy updating in non-excludable public goods game

    NASA Astrophysics Data System (ADS)

    Li, Yixiao; Shen, Bin

    2013-10-01

    Spatial public goods game is a popular metaphor to model the dilemma of collective cooperation on graphs, yet the non-excludable property of public goods has seldom been considered in previous models. Based upon a coevolutionary model where agents play public goods games and adjust their partnerships, the present model incorporates the non-excludable property of public goods: agents are able to adjust their participation in the games hosted by others, whereas they cannot exclude others from their own games. In the coevolution, a directed and dynamical network which represents partnerships among autonomous agents is evolved. We find that non-excludable property counteracts the positive effect of partner switching, i.e., the equilibrium level of cooperation is lower than that in the situation of excludable public goods game. Therefore, we study the effect of individual punishment that cooperative agents pay a personal cost to decrease benefits of those defective neighbors who participate in their hosted games. It is found that the cooperation level in the whole population is heightened in the presence of such a costly behavior.

  17. Learning dynamics in public goods games.

    PubMed

    Bladon, Alex J; Galla, Tobias

    2011-10-01

    We extend recent analyses of stochastic effects in game dynamical learning to cases of multiplayer games and to games defined on networked structures. By means of an expansion in the noise strength we consider the weak-noise limit and present an analytical computation of spectral properties of fluctuations in multiplayer public goods games. This extends existing work on two-player games. In particular we show that coherent cycles may emerge driven by noise in the adaptation dynamics. These phenomena are not too dissimilar from cyclic strategy switching observed in experiments of behavioral game theory. PMID:22181112

  18. Some Classes of Imperfect Information Finite State-Space Stochastic Games with Finite-Dimensional Solutions

    SciTech Connect

    McEneaney, William M.

    2004-08-15

    Stochastic games under imperfect information are typically computationally intractable even in the discrete-time/discrete-state case considered here. We consider a problem where one player has perfect information.A function of a conditional probability distribution is proposed as an information state.In the problem form here, the payoff is only a function of the terminal state of the system,and the initial information state is either linear ora sum of max-plus delta functions.When the initial information state belongs to these classes, its propagation is finite-dimensional.The state feedback value function is also finite-dimensional,and obtained via dynamic programming,but has a nonstandard form due to the necessity of an expanded state variable.Under a saddle point assumption,Certainty Equivalence is obtained and the proposed function is indeed an information state.

  19. A Stochastic Single-Molecule Event Triggers Phenotype Switching of a Bacterial Cell

    NASA Astrophysics Data System (ADS)

    Xie, Sunney; Choi, Paul; Cai, Long

    2009-03-01

    By monitoring fluorescently labeled lactose permease with single-molecule sensitivity, we investigated the molecular mechanism of how an Escherichia coli cell with the lac operon switches from one phenotype to another. At intermediate inducer concentrations, a population of genetically identical cells exhibits two phenotypes: induced cells with highly fluorescent membranes and uninduced cells with a small number of membrane-bound permeases. We found that this basal-level expression results from partial dissociation of the tetrameric lactose repressor from one of its operators on looped DNA. In contrast, infrequent events of complete dissociation of the repressor from DNA result in large bursts of permease expression that trigger induction of the lac operon. Hence, a stochastic single-molecule event determines a cell's phenotype.

  20. Cortical Contractility Triggers a Stochastic Switch to Fast Amoeboid Cell Motility

    PubMed Central

    Ruprecht, Verena; Wieser, Stefan; Callan-Jones, Andrew; Smutny, Michael; Morita, Hitoshi; Sako, Keisuke; Barone, Vanessa; Ritsch-Marte, Monika; Sixt, Michael; Voituriez, Raphal; Heisenberg, Carl-Philipp

    2015-01-01

    Summary 3D amoeboid cell migration is central to many developmental and disease-related processes such as cancer metastasis. Here, we identify a unique prototypic amoeboid cell migration mode in early zebrafish embryos, termed stable-bleb migration. Stable-bleb cells display an invariant polarized balloon-like shape with exceptional migration speed and persistence. Progenitor cells can be reversibly transformed into stable-bleb cells irrespective of their primary fate and motile characteristics by increasing myosin II activity through biochemical or mechanical stimuli. Using a combination of theory and experiments, we show that, in stable-bleb cells, cortical contractility fluctuations trigger a stochastic switch into amoeboid motility, and a positive feedback between cortical flows and gradients in contractility maintains stable-bleb cell polarization. We further show that rearward cortical flows drive stable-bleb cell migration in various adhesive and non-adhesive environments, unraveling a highly versatile amoeboid migration phenotype. PMID:25679761

  1. Feature of Dynamic Games for Discrete-time Weakly Coupled Large-scale Stochastic Systems

    NASA Astrophysics Data System (ADS)

    Mukaidani, Hiroaki; Xu, Hua

    This paper discusses the dynamic games for a class of discrete time weakly coupled large-scale stochastic systems. First, it is shown that Pareto and Nash strategy set can be designed by solving the cross-coupled stochastic discrete algebraic Riccati equations (CSDAREs). After establishing the asymptotic structure for these solutions of CSDAREs, weak coupling parameter independent strategy sets are given for their problems respectively. It is shown for the first time that these parameter-independent strategy sets are the same and the proposed strategy sets attain the Pareto suboptimarity and the approximate Nash equilibrium. In fact, it is proved that these strategy sets achieve O(?2) approximation for all cost performances. Furthermore, it is worth pointing out that the proposed approximate strategy sets can be constructed by solving the parameter independent reduced-order discrete algebraic Riccati equations (DAREs) via LMI. As a result, the suboptimality of overall cost for each subsystem can be attained. Finally, in order to demonstrate the efficiency of the proposed design method, a numerical example is provided.

  2. The Stability of a Stochastic CaMKII Switch: Dependence on the Number of Enzyme Molecules and Protein Turnover

    PubMed Central

    2005-01-01

    Molecular switches have been implicated in the storage of information in biological systems. For small structures such as synapses, these switches are composed of only a few molecules and stochastic fluctuations are therefore of importance. Such fluctuations could potentially lead to spontaneous switch reset that would limit the lifetime of information storage. We have analyzed a model of the calcium/calmodulin-dependent protein kinase II (CaMKII) switch implicated in long-term memory in the nervous system. The bistability of this switch arises from autocatalytic autophosphorylation of CaMKII, a reaction that is countered by a saturable phosphatase-1-mediated dephosphorylation. We sought to understand the factors that control switch stability and to determine the functional relationship between stability and the number of molecules involved. Using Monte Carlo simulations, we found that the lifetime of states of the switch increase exponentially with the number of CaMKII holoenzymes. Switch stability requires a balance between the kinase and phosphatase rates, and the kinase rate must remain high relative to the rate of protein turnover. Thus, a critical limit on switch stability is set by the observed turnover rate (one per 30 h on average). Our computational results show that, depending on the timescale of fluctuations in enzyme numbers, for a switch composed of about 15 CaMKII holoenzymes, the stable persistent activation can span from a few years to a human lifetime. PMID:15819604

  3. Stochastic Phenotype Transition of a Single Cell in an Intermediate Region of Gene State Switching

    NASA Astrophysics Data System (ADS)

    Ge, Hao; Qian, Hong; Xie, X. Sunney

    2015-02-01

    Multiple phenotypic states often arise in a single cell with different gene-expression states that undergo transcription regulation with positive feedback. Recent experiments show that, at least in E. coli, the gene state switching can be neither extremely slow nor exceedingly rapid as many previous theoretical treatments assumed. Rather, it is in the intermediate region which is difficult to handle mathematically. Under this condition, from a full chemical-master-equation description we derive a model in which the protein copy number, for a given gene state, follows a deterministic mean-field description while the protein-synthesis rates fluctuate due to stochastic gene state switching. The simplified kinetics yields a nonequilibrium landscape function, which, similar to the energy function for equilibrium fluctuation, provides the leading orders of fluctuations around each phenotypic state, as well as the transition rates between the two phenotypic states. This rate formula is analogous to Kramers' theory for chemical reactions. The resulting behaviors are significantly different from the two limiting cases studied previously.

  4. Dissociable effects of game elements on motivation and cognition in a task-switching training in middle childhood

    PubMed Central

    Dörrenbächer, Sandra; Müller, Philipp M.; Tröger, Johannes; Kray, Jutta

    2014-01-01

    Although motivational reinforcers are often used to enhance the attractiveness of trainings of cognitive control in children, little is known about how such motivational manipulations of the setting contribute to separate gains in motivation and cognitive-control performance. Here we provide a framework for systematically investigating the impact of a motivational video-game setting on the training motivation, the task performance, and the transfer success in a task-switching training in middle-aged children (8–11 years of age). We manipulated both the type of training (low-demanding/single-task training vs. high-demanding/task-switching training) as well as the motivational setting (low-motivational/without video-game elements vs. high-motivational/with video-game elements) separately from another. The results indicated that the addition of game elements to a training setting enhanced the intrinsic interest in task practice, independently of the cognitive demands placed by the training type. In the task-switching group, the high-motivational training setting led to an additional enhancement of task and switching performance during the training phase right from the outset. These motivation-induced benefits projected onto the switching performance in a switching situation different from the trained one (near-transfer measurement). However, in structurally dissimilar cognitive tasks (far-transfer measurement), the motivational gains only transferred to the response dynamics (speed of processing). Hence, the motivational setting clearly had a positive impact on the training motivation and on the paradigm-specific task-switching abilities; it did not, however, consistently generalize on broad cognitive processes. These findings shed new light on the conflation of motivation and cognition in childhood and may help to refine guidelines for designing adequate training interventions. PMID:25431564

  5. Recursive Computation of Static Output Feedback Stochastic Nash Games for Weakly-Coupled Large-Scale Systems

    NASA Astrophysics Data System (ADS)

    Sagara, Muneomi; Mukaidani, Hiroaki; Yamamoto, Toru

    This paper discusses the infinite horizon static output feedback stochastic Nash games involving state-dependent noise in weakly coupled large-scale systems. In order to construct the strategy, the conditions for the existence of equilibria have been derived from the solutions of the sets of cross-coupled stochastic algebraic Riccati equations (CSAREs). After establishing the asymptotic structure along with the positive semidefiniteness for the solutions of CSAREs, recursive algorithm for solving CSAREs is derived. As a result, it is shown that the proposed algorithm attains the reduced-order computations and the reduction of the CPU time. As another important contribution, the uniqueness of the strategy set is proved for the sufficiently small parameter ?. Finally, in order to demonstrate the efficiency of the proposed algorithm, numerical example is given.

  6. Stochastic analysis of the GAL genetic switch in Saccharomyces cerevisiae: Modeling and experiments reveal hierarchy in glucose repression

    PubMed Central

    Prasad, Vinay; Venkatesh, KV

    2008-01-01

    Background Transcriptional regulation involves protein-DNA and protein-protein interactions. Protein-DNA interactions involve reactants that are present in low concentrations, leading to stochastic behavior. In addition, multiple regulatory mechanisms are typically involved in transcriptional regulation. In the GAL regulatory system of Saccharomyces cerevisiae, the inhibition of glucose is accomplished through two regulatory mechanisms: one through the transcriptional repressor Mig1p, and the other through regulating the amount of transcriptional activator Gal4p. However, the impact of stochasticity in gene expression and hierarchy in regulatory mechanisms on the phenotypic level is not clearly understood. Results We address the question of quantifying the effect of stochasticity inherent in these regulatory mechanisms on the performance of various genes under the regulation of Mig1p and Gal4p using a dynamic stochastic model. The stochastic analysis reveals the importance of both the mechanisms of regulation for tight expression of genes in the GAL network. The mechanism involving Gal4p is the dominant mechanism, yielding low variability in the expression of GAL genes. The mechanism involving Mig1p is necessary to maintain the switch-like response of certain GAL genes. The number of binding sites for Mig1p and Gal4p further influences the expression of the genes, with extra binding sites lowering the variability of expression. Our experiments involving growth on various substrates show that the trends predicted in mean expression and its variability are transmitted to the phenotypic level. Conclusion The mechanisms involved in the transcriptional regulation and their variability set up a hierarchy in the phenotypic response to growth on various substrates. Structural motifs, such as the number of binding sites and the mechanism of regulation, determine the level of stochasticity and eventually, the phenotypic response. PMID:19014615

  7. Stochastic dynamics of phase-slip trains and superconductive-resistive switching in current-biased nanowires

    NASA Astrophysics Data System (ADS)

    Pekker, David; Shah, Nayana; Sahu, Mitrabhanu; Bezryadin, Alexey; Goldbart, Paul M.

    2009-12-01

    Superconducting nanowires fabricated via carbon-nanotube templating can be used to realize and study quasi-one-dimensional superconductors. However, measurement of the linear resistance of these nanowires have been inconclusive in determining the low-temperature behavior of phase-slip fluctuations, both quantal and thermal. Thus, we are motivated to study the nonlinear current-voltage characteristics in current-biased nanowires and the stochastic dynamics of superconductive-resistive switching, as a way of probing phase-slip events. In particular, we address the question: can a single phase-slip event occurring somewhere along the wire—during which the order-parameter fluctuates to zero—induce switching, via the local heating it causes? We explore this and related issues by constructing a stochastic model for the time evolution of the temperature in a nanowire whose ends are maintained at a fixed temperature. We derive the corresponding master equation as a tool for evaluating and analyzing the mean switching time at a given value of current (smaller than the depairing critical current). The model indicates that although, in general, several phase-slip events are necessary to induce switching via a thermal runaway, there is indeed a regime of temperatures and currents in which a single event is sufficient. We carry out a detailed comparison of the results of the model with experimental measurements of the distribution of switching currents, and provide an explanation for the rather counterintuitive broadening of the distribution width that is observed upon lowering the temperature. Moreover, we identify a regime in which the experiments are probing individual phase-slip events, and thus offer a way of unearthing and exploring the physics of nanoscale quantum tunneling of the one-dimensional collective quantum field associated with the superconducting order parameter.

  8. Asymptotic properties of a stochastic n-species Gilpin-Ayala competitive model with Lvy jumps and Markovian switching

    NASA Astrophysics Data System (ADS)

    Liu, Qun

    2015-09-01

    In this paper, a stochastic n-species Gilpin-Ayala competitive model with Lvy jumps and Markovian switching is proposed and studied. Some asymptotic properties are investigated and sufficient conditions for extinction, non-persistence in the mean and weak persistence are established. The threshold between extinction and weak persistence is obtained. The results illustrate that the asymptotic properties of the considered system have close relationships with Lvy jumps and the stationary distribution of the Markovian chain. Moreover, some simulation figures are presented to confirm our main results.

  9. Viscosity Solutions for a System of Integro-PDEs and Connections to Optimal Switching and Control of Jump-Diffusion Processes

    SciTech Connect

    Biswas, Imran H.; Jakobsen, Espen R.; Karlsen, Kenneth H.

    2010-08-15

    We develop a viscosity solution theory for a system of nonlinear degenerate parabolic integro-partial differential equations (IPDEs) related to stochastic optimal switching and control problems or stochastic games. In the case of stochastic optimal switching and control, we prove via dynamic programming methods that the value function is a viscosity solution of the IPDEs. In our setting the value functions or the solutions of the IPDEs are not smooth, so classical verification theorems do not apply.

  10. Strategy switches and co-action equilibria in a minority game

    NASA Astrophysics Data System (ADS)

    Sasidevan, V.; Dhar, Deepak

    2014-05-01

    We propose an analytically tractable variation of the minority game in which rational agents use probabilistic strategies. In our model, N agents choose between two alternatives repeatedly, and those who are in the minority get a pay-off 1, others zero. The agents optimize the expectation value of their discounted future pay-off, the discount parameter being ?. We propose an alternative to the standard Nash equilibrium, called co-action equilibrium, which gives higher expected pay-off for all agents. The optimal choice of probabilities of different actions are determined exactly in terms of simple self-consistent equations. The optimal strategy is characterized by N real parameters, which are non-analytic functions of ?, even for a finite number of agents. The solution for N?7 is worked out explicitly indicating the structure of the solution for larger N. For large enough future time horizon, the optimal strategy switches from random choice to a win-stay lose-shift strategy, with the shift probability depending on the current state and ?.

  11. Delays-based protein switches in a stochastic single-gene network

    NASA Astrophysics Data System (ADS)

    Zhang, Chun; Zeng, Jiakui; Tian, Dong; Luo, Hongchun; Yang, Tao; Han, Qinglin; Xiang, Chao; Zeng, Chunhua; Wang, Canjun

    2015-09-01

    In this paper, the protein switch in a single-gene network with time delays is investigated, where the gene expression is assumed to be disturbed by multiplicative and additive noises. The impacts of time delays ?d and ?s in degradation and synthesis processes, time delay ?g in global process and cross-correlation between two noises (?i, and i = d , s , g) on the probability distribution and switch time (ST) from low protein level (OFF state) to high one (ON state) are discussed, respectively. Our results show that (1) the increase of the cross-correlation between two noises (?i) can induce protein switches from ON state to OFF one; (2) for ?i ? 0, the increase of ?d can induce protein switches from OFF state to ON one, while ?s (or ?g) can induce protein switches from the ON state to the OFF one, but for ?i < 0, the ?d (or ?s) can induce protein switches from the OFF state to the ON one, while ?g can induce protein switches from the ON state to the OFF one; (3) the ST as functions of the noise intensities exhibits a maximum, which is the signature of the noise enhanced stability (NES) of the OFF state, while the increase of ?d can cause the NES phenomenon to disappear; and (4) ?d and ?s play opposing roles in the ST, i.e., the impacts of the time delays ?d and ?s on ST can be canceled each other out.

  12. Towards Stability Analysis of Jump Linear Systems with State-Dependent and Stochastic Switching

    NASA Technical Reports Server (NTRS)

    Tejada, Arturo; Gonzalez, Oscar R.; Gray, W. Steven

    2004-01-01

    This paper analyzes the stability of hierarchical jump linear systems where the supervisor is driven by a Markovian stochastic process and by the values of the supervised jump linear system s states. The stability framework for this class of systems is developed over infinite and finite time horizons. The framework is then used to derive sufficient stability conditions for a specific class of hybrid jump linear systems with performance supervision. New sufficient stochastic stability conditions for discrete-time jump linear systems are also presented.

  13. Stochastic switching of TiO2-based memristive devices with identical initial memory states

    PubMed Central

    2014-01-01

    In this work, we show that identical TiO2-based memristive devices that possess the same initial resistive states are only phenomenologically similar as their internal structures may vary significantly, which could render quite dissimilar switching dynamics. We experimentally demonstrated that the resistive switching of practical devices with similar initial states could occur at different programming stimuli cycles. We argue that similar memory states can be transcribed via numerous distinct active core states through the dissimilar reduced TiO2-x filamentary distributions. Our hypothesis was finally verified via simulated results of the memory state evolution, by taking into account dissimilar initial filamentary distribution. PMID:24994953

  14. Using Nonlinear Stochastic Evolutionary Game Strategy to Model an Evolutionary Biological Network of Organ Carcinogenesis Under a Natural Selection Scheme

    PubMed Central

    Chen, Bor-Sen; Tsai, Kun-Wei; Li, Cheng-Wei

    2015-01-01

    Molecular biologists have long recognized carcinogenesis as an evolutionary process that involves natural selection. Cancer is driven by the somatic evolution of cell lineages. In this study, the evolution of somatic cancer cell lineages during carcinogenesis was modeled as an equilibrium point (ie, phenotype of attractor) shifting, the process of a nonlinear stochastic evolutionary biological network. This process is subject to intrinsic random fluctuations because of somatic genetic and epigenetic variations, as well as extrinsic disturbances because of carcinogens and stressors. In order to maintain the normal function (ie, phenotype) of an evolutionary biological network subjected to random intrinsic fluctuations and extrinsic disturbances, a network robustness scheme that incorporates natural selection needs to be developed. This can be accomplished by selecting certain genetic and epigenetic variations to modify the network structure to attenuate intrinsic fluctuations efficiently and to resist extrinsic disturbances in order to maintain the phenotype of the evolutionary biological network at an equilibrium point (attractor). However, during carcinogenesis, the remaining (or neutral) genetic and epigenetic variations accumulate, and the extrinsic disturbances become too large to maintain the normal phenotype at the desired equilibrium point for the nonlinear evolutionary biological network. Thus, the network is shifted to a cancer phenotype at a new equilibrium point that begins a new evolutionary process. In this study, the natural selection scheme of an evolutionary biological network of carcinogenesis was derived from a robust negative feedback scheme based on the nonlinear stochastic Nash game strategy. The evolvability and phenotypic robustness criteria of the evolutionary cancer network were also estimated by solving a HamiltonJacobi inequality constrained optimization problem. The simulation revealed that the phenotypic shift of the lung cancer-associated cell network takes 54.5 years from a normal state to stage I cancer, 1.5 years from stage I to stage II cancer, and 2.5 years from stage II to stage III cancer, with a reasonable match for the statistical result of the average age of lung cancer. These results suggest that a robust negative feedback scheme, based on a stochastic evolutionary game strategy, plays a critical role in an evolutionary biological network of carcinogenesis under a natural selection scheme. PMID:26244004

  15. Control systems with stochastic feedback

    NASA Astrophysics Data System (ADS)

    Allison, Andrew; Abbott, Derek

    2001-09-01

    In this paper we use the analogy of Parrondo's games to design a second order switched mode circuit which is unstable in either mode but is stable when switched. We do not require any sophisticated control law. The circuit is stable, even if it is switched at random. We use a stochastic form of Lyapunov's second method to prove that the randomly switched system is stable with probability of one. Simulations show that the solution to the randomly switched system is very similar to the analytic solution for the time-averaged system. This is consistent with the standard techniques for switched state-space systems with periodic switching. We perform state-space simulations of our system, with a randomized discrete-time switching policy. We also examine the case where the control variable, the loop gain, is a continuous Gaussian random variable. This gives rise to a matrix stochastic differential equation (SDE). We know that, for a one-dimensional SDE, the difference between solution for the time averaged system and any given sample path for the SDE will be an appropriately scaled and conditioned version of Brownian motion. The simulations show that this is approximately true for the matrix SDE. We examine some numerical solutions to the matrix SDE in the time and frequency domains, for the case where the noise power is very small. We also perform some simulations, without analysis, for the same system with large amounts of noise. In this case, the solution is significantly shifted away from the solution for the time-averaged system. The Brownian motion terms dominate all other aspects of the solution. This gives rise to very erratic and "bursty" behavior. The stored energy in the system takes the form a logarithmic random walk. The simulations of our curious circuit suggest that it is possible to implement a control algorithm that actively uses noise, although too much noise eventually makes the system unusable.

  16. Ssn6 Defines a New Level of Regulation of White-Opaque Switching in Candida albicans and Is Required For the Stochasticity of the Switch

    PubMed Central

    Lohse, Matthew B.; Nobile, Clarissa J.; Noiman, Liron; Laksana, Clement N.

    2016-01-01

    ABSTRACT The human commensal and opportunistic pathogen Candida albicans can switch between two distinct, heritable cell types, named “white” and “opaque,” which differ in morphology, mating abilities, and metabolic preferences and in their interactions with the host immune system. Previous studies revealed a highly interconnected group of transcriptional regulators that control switching between the two cell types. Here, we identify Ssn6, the C. albicans functional homolog of the Saccharomyces cerevisiae transcriptional corepressor Cyc8, as a new regulator of white-opaque switching. In a or α mating type strains, deletion of SSN6 results in mass switching from the white to the opaque cell type. Transcriptional profiling of ssn6 deletion mutant strains reveals that Ssn6 represses part of the opaque cell transcriptional program in white cells and the majority of the white cell transcriptional program in opaque cells. Genome-wide chromatin immunoprecipitation experiments demonstrate that Ssn6 is tightly integrated into the opaque cell regulatory circuit and that the positions to which it is bound across the genome strongly overlap those bound by Wor1 and Wor2, previously identified regulators of white-opaque switching. This work reveals the next layer in the white-opaque transcriptional circuitry by integrating a transcriptional regulator that does not bind DNA directly but instead associates with specific combinations of DNA-bound transcriptional regulators. PMID:26814177

  17. Stability and Multiattractor Dynamics of a Toggle Switch Based on a Two-Stage Model of Stochastic Gene Expression

    PubMed Central

    Strasser, Michael; Theis, FabianJ.; Marr, Carsten

    2012-01-01

    A toggle switch consists of two genes that mutually repress each other. This regulatory motif is active during cell differentiation and is thought to act as a memory device, being able to choose and maintain cell fate decisions. Commonly, this switch has been modeled in a deterministic framework where transcription and translation are lumped together. In this description, bistability occurs for transcription factor cooperativity, whereas autoactivation leads to a tristable system with an additional undecided state. In this contribution, we study the stability and dynamics of a two-stage gene expression switch withina probabilistic framework inspired by the properties of the Pu/Gata toggle switch in myeloid progenitor cells. We focus on low mRNA numbers, high protein abundance, and monomeric transcription-factor binding. Contrary to the expectation from a deterministic description, this switch shows complex multiattractor dynamics without autoactivation and cooperativity. Most importantly, the four attractors of the system, which only emerge in a probabilistic two-stage description, can be identified with committed and primed states in cell differentiation. To begin, we study the dynamics of the system and infer the mechanisms that move the system between attractors using both the quasipotential and the probability flux of the system. Next, we show that the residence times of the system in one of the committed attractors are geometrically distributed. We derive an analytical expression for the parameter of the geometric distribution, therefore completely describing the statistics of the switching process and elucidate the influence of the system parameters on the residence time. Moreover, we find that the mean residence time increases linearly with the mean protein level. This scaling also holds for a one-stage scenario and for autoactivation. Finally, we study the implications of this distribution for the stability of a switch and discuss the influence of the stability on a specific cell differentiation mechanism. Our model explains lineage priming and proposes the need of either high protein numbers or long-term modifications such as chromatin remodeling to achieve stable cell fate decisions. Notably, we present a system with high protein abundance that nevertheless requires a probabilistic description to exhibit multistability, complex switching dynamics, and lineage priming. PMID:22225794

  18. Stability and multiattractor dynamics of a toggle switch based on a two-stage model of stochastic gene expression.

    PubMed

    Strasser, Michael; Theis, Fabian J; Marr, Carsten

    2012-01-01

    A toggle switch consists of two genes that mutually repress each other. This regulatory motif is active during cell differentiation and is thought to act as a memory device, being able to choose and maintain cell fate decisions. Commonly, this switch has been modeled in a deterministic framework where transcription and translation are lumped together. In this description, bistability occurs for transcription factor cooperativity, whereas autoactivation leads to a tristable system with an additional undecided state. In this contribution, we study the stability and dynamics of a two-stage gene expression switch within a probabilistic framework inspired by the properties of the Pu/Gata toggle switch in myeloid progenitor cells. We focus on low mRNA numbers, high protein abundance, and monomeric transcription-factor binding. Contrary to the expectation from a deterministic description, this switch shows complex multiattractor dynamics without autoactivation and cooperativity. Most importantly, the four attractors of the system, which only emerge in a probabilistic two-stage description, can be identified with committed and primed states in cell differentiation. To begin, we study the dynamics of the system and infer the mechanisms that move the system between attractors using both the quasipotential and the probability flux of the system. Next, we show that the residence times of the system in one of the committed attractors are geometrically distributed. We derive an analytical expression for the parameter of the geometric distribution, therefore completely describing the statistics of the switching process and elucidate the influence of the system parameters on the residence time. Moreover, we find that the mean residence time increases linearly with the mean protein level. This scaling also holds for a one-stage scenario and for autoactivation. Finally, we study the implications of this distribution for the stability of a switch and discuss the influence of the stability on a specific cell differentiation mechanism. Our model explains lineage priming and proposes the need of either high protein numbers or long-term modifications such as chromatin remodeling to achieve stable cell fate decisions. Notably, we present a system with high protein abundance that nevertheless requires a probabilistic description to exhibit multistability, complex switching dynamics, and lineage priming. PMID:22225794

  19. Self-organizing patterns in an evolutionary rock-paper-scissors game for stochastic synchronized strategy updates

    NASA Astrophysics Data System (ADS)

    Varga, Levente; Vukov, Jeromos; Szab, Gyrgy

    2014-10-01

    We study a spatial evolutionary rock-paper-scissors game with synchronized strategy updating. Players gain their payoff from games with their four neighbors on a square lattice and can update their strategies simultaneously according to the logit rule, which is the noisy version of the best-response dynamics. For the synchronized strategy update two types of global oscillations (with an ordered strategy arrangement and periods of three and six generations) can occur in this system in the zero noise limit. At low noise values, all nine oscillating phases are present in the system by forming a self-organizing spatial pattern due to the comprising invasion and speciation processes along the interfaces separating the different domains.

  20. Active Learning with Monty Hall in a Game Theory Class

    ERIC Educational Resources Information Center

    Brokaw, Alan J.; Merz, Thomas E.

    2004-01-01

    The authors describe a game that students can play on the first day of a game theory class. The game introduces the 4 essential elements of any game and is designed so that its sequel, also played on the first day of class, has students playing the well-known Monty Hall game, which raises the question: Should you switch doors? By implementing a

  1. A Monetary Policy Simulation Game

    ERIC Educational Resources Information Center

    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,

  2. A Monetary Policy Simulation Game

    ERIC Educational Resources Information Center

    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,…

  3. Statistical equilibrium in simple exchange games II. The redistribution game

    NASA Astrophysics Data System (ADS)

    Garibaldi, U.; Scalas, E.; Viarengo, P.

    2007-11-01

    We propose a simple stochastic exchange game mimicking taxation and redistribution. There are g agents and n coins; taxation is modeled by randomly extracting some coins; then, these coins are redistributed to agents following Polya's scheme. The individual wealth equilibrium distribution for the resulting Markov chain is the multivariate symmetric Polya distribution. In the continuum limit, the wealth distribution converges to a Gamma distribution, whose form factor is just the initial redistribution weight. The relationship between this taxation-and-redistribution scheme and other simple conservative stochastic exchange games (such as the BDY game) is discussed.

  4. Bacterial Games

    NASA Astrophysics Data System (ADS)

    Frey, Erwin; Reichenbach, Tobias

    Microbial laboratory communities have become model systems for studying the complex interplay between nonlinear dynamics of evolutionary selection forces, stochastic fluctuations arising from the probabilistic nature of interactions, and spatial organization. Major research goals are to identify and understand mechanisms that ensure viability of microbial colonies by allowing for species diversity, cooperative behavior and other kinds of "social" behavior. A synthesis of evolutionary game theory, nonlinear dynamics, and the theory of stochastic processes provides the mathematical tools and conceptual framework for a deeper understanding of these ecological systems. We give an introduction to the modern formulation of these theories and illustrate their effectiveness, focusing on selected examples of microbial systems. Intrinsic fluctuations, stemming from the discreteness of individuals, are ubiquitous, and can have important impact on the stability of ecosystems. In the absence of speciation, extinction of species is unavoidable, may, however, take very long times. We provide a general concept for defining survival and extinction on ecological time scales. Spatial degrees of freedom come with a certain mobility of individuals. When the latter is sufficiently high, bacterial community structures can be understood through mapping individual-based models, in a continuum approach, onto stochastic partial differential equations. These allow progress using methods of nonlinear dynamics such as bifurcation analysis and invariant manifolds. We conclude with a perspective on the current challenges in quantifying bacterial pattern formation, and how this might have an impact on fundamental research in nonequilibrium physics .

  5. Backward Stochastic Differential Equations in Infinite Dimensions with Continuous Driver and Applications

    SciTech Connect

    Fuhrman, Marco Hu, Ying

    2007-09-15

    In this paper we prove the existence of a solution to backward stochastic differential equations in infinite dimensions with continuous driver under various assumptions. We apply our results to a stochastic game problem with infinitely many players.

  6. The local minority game

    NASA Astrophysics Data System (ADS)

    Moelbert, S.; De Los Rios, P.

    2002-01-01

    Ecologists and economists try to explain collective behavior in terms of competitive systems of selfish individuals with the ability to learn from the past. Statistical physicists have been investigating models which might contribute to the understanding of the underlying mechanisms of these systems. During the last 3 yr one intuitive model, commonly referred to as the minority game (MG), has attracted considerable attention. Powerful yet simple, the minority game has produced encouraging results which can explain the temporal behavior of competitive systems. Here we switch the interest to the phenomena due to a distribution of the individuals in space. For analyzing these effects we modify the minority game and the local minority game (LMG) is introduced. We study the system both numerically and analytically, using the customary techniques already developed for the ordinary Minority Game.

  7. Identifying effective connectivity parameters in simulated fMRI: a direct comparison of switching linear dynamic system, stochastic dynamic causal, and multivariate autoregressive models

    PubMed Central

    Smith, Jason F.; Chen, Kewei; Pillai, Ajay S.; Horwitz, Barry

    2013-01-01

    The number and variety of connectivity estimation methods is likely to continue to grow over the coming decade. Comparisons between methods are necessary to prune this growth to only the most accurate and robust methods. However, the nature of connectivity is elusive with different methods potentially attempting to identify different aspects of connectivity. Commonalities of connectivity definitions across methods upon which base direct comparisons can be difficult to derive. Here, we explicitly define “effective connectivity” using a common set of observation and state equations that are appropriate for three connectivity methods: dynamic causal modeling (DCM), multivariate autoregressive modeling (MAR), and switching linear dynamic systems for fMRI (sLDSf). In addition while deriving this set, we show how many other popular functional and effective connectivity methods are actually simplifications of these equations. We discuss implications of these connections for the practice of using one method to simulate data for another method. After mathematically connecting the three effective connectivity methods, simulated fMRI data with varying numbers of regions and task conditions is generated from the common equation. This simulated data explicitly contains the type of the connectivity that the three models were intended to identify. Each method is applied to the simulated data sets and the accuracy of parameter identification is analyzed. All methods perform above chance levels at identifying correct connectivity parameters. The sLDSf method was superior in parameter estimation accuracy to both DCM and MAR for all types of comparisons. PMID:23717258

  8. Stochastic resonance

    NASA Astrophysics Data System (ADS)

    Gammaitoni, Luca; Hänggi, Peter; Jung, Peter; Marchesoni, Fabio

    1998-01-01

    Over the last two decades, stochastic resonance has continuously attracted considerable attention. The term is given to a phenomenon that is manifest in nonlinear systems whereby generally feeble input information (such as a weak signal) can be be amplified and optimized by the assistance of noise. The effect requires three basic ingredients: (i) an energetic activation barrier or, more generally, a form of threshold; (ii) a weak coherent input (such as a periodic signal); (iii) a source of noise that is inherent in the system, or that adds to the coherent input. Given these features, the response of the system undergoes resonance-like behavior as a function of the noise level; hence the name stochastic resonance. The underlying mechanism is fairly simple and robust. As a consequence, stochastic resonance has been observed in a large variety of systems, including bistable ring lasers, semiconductor devices, chemical reactions, and mechanoreceptor cells in the tail fan of a crayfish. In this paper, the authors report, interpret, and extend much of the current understanding of the theory and physics of stochastic resonance. They introduce the readers to the basic features of stochastic resonance and its recent history. Definitions of the characteristic quantities that are important to quantify stochastic resonance, together with the most important tools necessary to actually compute those quantities, are presented. The essence of classical stochastic resonance theory is presented, and important applications of stochastic resonance in nonlinear optics, solid state devices, and neurophysiology are described and put into context with stochastic resonance theory. More elaborate and recent developments of stochastic resonance theory are discussed, ranging from fundamental quantum properties-being important at low temperatures-over spatiotemporal aspects in spatially distributed systems, to realizations in chaotic maps. In conclusion the authors summarize the achievements and attempt to indicate the most promising areas for future research in theory and experiment.

  9. Navajo Games.

    ERIC Educational Resources Information Center

    Cliff, Janet M.

    1990-01-01

    Reviews 163 sources on Navajo games, play, and toys. Includes an annotated bibliography of those materials. Examines relationships between games and religion, origin myths, and ceremonies. Discusses attitudes toward games, gambling, and cheating; and the dichotomy between children's and adults' games. Describes specific toys, games, and play…

  10. Playful Gaming.

    ERIC Educational Resources Information Center

    Makedon, Alexander

    A philosophical analysis of play and games is undertaken in this paper. Playful gaming, which is shown to be a synthesis of play and games, is utilized as a category for undertaking the examination of play and games. The significance of playful gaming to education is demonstrated through analyses of Plato's, Dewey's, Sartre's, and Marcuse's

  11. Stochastic Approximation to Understand Simple Simulation Models

    NASA Astrophysics Data System (ADS)

    Izquierdo, Segismundo S.; Izquierdo, Luis R.

    2013-04-01

    This paper illustrates how a deterministic approximation of a stochastic process can be usefully applied to analyse the dynamics of many simple simulation models. To demonstrate the type of results that can be obtained using this approximation, we present two illustrative examples which are meant to serve as methodological references for researchers exploring this area. Finally, we prove some convergence results for simulations of a family of evolutionary games, namely, intra-population imitation models in n-player games with arbitrary payoffs.

  12. Number Games.

    ERIC Educational Resources Information Center

    Crawford, David

    1997-01-01

    Presents three number games for mathematics classrooms designed to improve the learning of number concepts. Game topics include determining products, arranging mathematical signs, and factoring. (ASK)

  13. QB1 - Stochastic Gene Regulation

    SciTech Connect

    Munsky, Brian

    2012-07-23

    Summaries of this presentation are: (1) Stochastic fluctuations or 'noise' is present in the cell - Random motion and competition between reactants, Low copy, quantization of reactants, Upstream processes; (2) Fluctuations may be very important - Cell-to-cell variability, Cell fate decisions (switches), Signal amplification or damping, stochastic resonances; and (3) Some tools are available to mode these - Kinetic Monte Carlo simulations (SSA and variants), Moment approximation methods, Finite State Projection. We will see how modeling these reactions can tell us more about the underlying processes of gene regulation.

  14. Synchronization of noisy systems by stochastic signals

    SciTech Connect

    Neiman, A.; Schimansky-Geier, L.; Moss, F.; Schimansky-Geier, L.; Shulgin, B.; Collins, J.J.

    1999-07-01

    We study, in terms of synchronization, the {ital nonlinear response} of noisy bistable systems to a stochastic external signal, represented by Markovian dichotomic noise. We propose a general kinetic model which allows us to conduct a full analytical study of the nonlinear response, including the calculation of cross-correlation measures, the mean switching frequency, and synchronization regions. Theoretical results are compared with numerical simulations of a noisy overdamped bistable oscillator. We show that dichotomic noise can instantaneously synchronize the switching process of the system. We also show that synchronization is most pronounced at an optimal noise level{emdash}this effect connects this phenomenon with aperiodic stochastic resonance. Similar synchronization effects are observed for a stochastic neuron model stimulated by a stochastic spike train. {copyright} {ital 1999} {ital The American Physical Society}

  15. Synchronization of noisy systems by stochastic signals.

    PubMed

    Neiman, A; Schimansky-Geier, L; Moss, F; Shulgin, B; Collins, J J

    1999-07-01

    We study, in terms of synchronization, the nonlinear response of noisy bistable systems to a stochastic external signal, represented by Markovian dichotomic noise. We propose a general kinetic model which allows us to conduct a full analytical study of the nonlinear response, including the calculation of cross-correlation measures, the mean switching frequency, and synchronization regions. Theoretical results are compared with numerical simulations of a noisy overdamped bistable oscillator. We show that dichotomic noise can instantaneously synchronize the switching process of the system. We also show that synchronization is most pronounced at an optimal noise level-this effect connects this phenomenon with aperiodic stochastic resonance. Similar synchronization effects are observed for a stochastic neuron model stimulated by a stochastic spike train. PMID:11969761

  16. A Game Is Not a Gimmick.

    ERIC Educational Resources Information Center

    Foy, William C.

    Educational games can make the English classroom a giant playground for natural language opportunities. Some of the games include (1) the use of the animate-inanimate switch for a unit on the language of advertising, where the students use two decks of word cards (one for nouns and the other for adjectives), the purpose being to match the

  17. Games in Geography.

    ERIC Educational Resources Information Center

    Walford, Rex

    Six games designed for classroom use are described in this book: 1) Shopping Game; 2) Bus Service Game; 3) North Sea Gas Game; 4) Railway Pioneers Game; 5) Development Game; and 6) Export Drive Game. The description of each game comprises a separate chapter, and includes information about the general aims of the game, how the various game elements

  18. Stability of Zero-Sum Games in Evolutionary Game Theory

    NASA Astrophysics Data System (ADS)

    Knebel, Johannes; Krueger, Torben; Weber, Markus F.; Frey, Erwin

    2014-03-01

    Evolutionary game theory has evolved into a successful theoretical concept to study mechanisms that govern the evolution of ecological communities. On a mathematical level, this theory was formalized in the framework of the celebrated replicator equations (REs) and its stochastic generalizations. In our work, we analyze the long-time behavior of the REs for zero-sum games with arbitrarily many strategies, which are generalized versions of the children's game Rock-Paper-Scissors.[1] We demonstrate how to determine the strategies that survive and those that become extinct in the long run. Our results show that extinction of strategies is exponentially fast in generic setups, and that conditions for the survival can be formulated in terms of the Pfaffian of the REs' antisymmetric payoff matrix. Consequences for the stochastic dynamics, which arise in finite populations, are reflected by a generalized scaling law for the extinction time in the vicinity of critical reaction rates. Our findings underline the relevance of zero-sum games as a reference for the analysis of other models in evolutionary game theory.

  19. Stochastic thermodynamics

    NASA Astrophysics Data System (ADS)

    Eichhorn, Ralf; Aurell, Erik

    2014-04-01

    'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response theory for small deviations from equilibrium, in which a general framework is constructed from the analysis of non-equilibrium states close to equilibrium. In a next step, Prigogine and others developed linear irreversible thermodynamics, which establishes relations between transport coefficients and entropy production on a phenomenological level in terms of thermodynamic forces and fluxes. However, beyond the realm of linear response no general theoretical results were available for quite a long time. This situation has changed drastically over the last 20 years with the development of stochastic thermodynamics, revealing that the range of validity of thermodynamic statements can indeed be extended deep into the non-equilibrium regime. Early developments in that direction trace back to the observations of symmetry relations between the probabilities for entropy production and entropy annihilation in non-equilibrium steady states [5-8] (nowadays categorized in the class of so-called detailed fluctuation theorems), and the derivations of the Bochkov-Kuzovlev [9, 10] and Jarzynski relations [11] (which are now classified as so-called integral fluctuation theorems). Apart from its fundamental theoretical interest, the developments in stochastic thermodynamics have experienced an additional boost from the recent experimental progress in fabricating, manipulating, controlling and observing systems on the micro- and nano-scale. These advances are not only of formidable use for probing and monitoring biological processes on the cellular, sub-cellular and molecular level, but even include the realization of a microscopic thermodynamic heat engine [12] or the experimental verification of Landauer's principle in a colloidal system [13]. The scientific program Stochastic Thermodynamics held between 4 and 15 March 2013, and hosted by The Nordic Institute for Theoretical Physics (Nordita), was attended by more than 50 scientists from the Nordic countries and elsewhere, amongst them many leading experts in the field. During the program, the most recent developments, open questions and new ideas in stochastic thermodynamics were presented and discussed. From the talks and debates, the notion of information in stochastic thermodynamics, the fundamental properties of entropy production (rate) in non-equilibrium, the efficiency of small thermodynamic machines and the characteristics of optimal protocols for the applied (cyclic) forces were crystallizing as main themes. Surprisingly, the long-studied adiabatic piston, its peculiarities and its relation to stochastic thermodynamics were also the subject of intense discussions. The comment on the Nordita program Stochastic Thermodynamics published in this issue of Physica Scripta exploits the Jarzynski relation for determining free energy differences in the adiabatic piston. This scientific program and the contribution presented here were made possible by the financial and administrative support of The Nordic Institute for Theoretical Physics.

  20. [Game addiction].

    PubMed

    Mori, Akio; Iwadate, Masako; Minakawa, Nahoko T; Kawashima, Satoshi

    2015-09-01

    The purpose of this article is to analyze the South Korea and China of computer game research, and the current state of research in Japan. Excessive game actions were analyzed by PET-MRI, MRI, fMRI, NIRS, EEG. These results showed that the prefrontal cortical activity decreased during game play. Also, game addiction causes damage to the prefrontal cortex. The NIRS-EEG and simultaneous recording, during game play correspond well with the decrease of ? band and oxygen-hemoglobin. The ? band did not change with game play. However, oxygen-hemoglobin decreased during game play. South Korea, game addiction measures have been analyzed since 2002, but in Japan the research is recent. PMID:26394522

  1. Stochastic differential equations and numerical simulation for pedestrians

    SciTech Connect

    Garrison, J.C.

    1993-07-27

    The mathematical foundation of the Ito interpretation of stochastic ordinary and partial differential equations is briefly explained. This provides the basis for a review of simple difference approximations to stochastic differential equations. An example arising in the theory of optical switching is discussed.

  2. Analysis of Genetic Toggle Switch Systems Encoded on Plasmids

    NASA Astrophysics Data System (ADS)

    Loinger, Adiel; Biham, Ofer

    2009-08-01

    Genetic switch systems with mutual repression of two transcription factors, encoded on plasmids, are studied using stochastic methods. The plasmid copy number is found to strongly affect the behavior of these systems. More specifically, the average time between spontaneous switching events quickly increases with the number of plasmids. It was shown before that for a single copy encoded on the chromosome, the exclusive switch is more stable than the general switch. Here we show that when the switch is encoded on a sufficiently large number of plasmids, the situation is reversed and the general switch is more stable than the exclusive switch. These predictions can be tested experimentally using methods of synthetic biology.

  3. Winter Games.

    ERIC Educational Resources Information Center

    Tarbuth, Lawson, Comp.

    Educators may find activities for indoor and outdoor winter programs in the games of the traditional Eskimo. These games are dominated by few-step operations and low level structural organization. For the most part they are quickly organized, begun, terminated, and ready to be recommenced. All types of games can be found, including quiet ones,

  4. Constrained Stochastic Extended Redundancy Analysis.

    PubMed

    DeSarbo, Wayne S; Hwang, Heungsun; Stadler Blank, Ashley; Kappe, Eelco

    2015-06-01

    We devise a new statistical methodology called constrained stochastic extended redundancy analysis (CSERA) to examine the comparative impact of various conceptual factors, or drivers, as well as the specific predictor variables that contribute to each driver on designated dependent variable(s). The technical details of the proposed methodology, the maximum likelihood estimation algorithm, and model selection heuristics are discussed. A sports marketing consumer psychology application is provided in a Major League Baseball (MLB) context where the effects of six conceptual drivers of game attendance and their defining predictor variables are estimated. Results compare favorably to those obtained using traditional extended redundancy analysis (ERA). PMID:24327066

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

    SciTech Connect

    Gruen, Christine

    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.

  6. Switch wear leveling

    DOEpatents

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

    2015-09-01

    An apparatus for switch wear leveling includes a switching module that controls switching for two or more pairs of switches in a switching power converter. The switching module controls switches based on a duty cycle control technique and closes and opens each switch in a switching sequence. The pairs of switches connect to a positive and negative terminal of a DC voltage source. For a first switching sequence a first switch of a pair of switches has a higher switching power loss than a second switch of the pair of switches. The apparatus includes a switch rotation module that changes the switching sequence of the two or more pairs of switches from the first switching sequence to a second switching sequence. The second switch of a pair of switches has a higher switching power loss than the first switch of the pair of switches during the second switching sequence.

  7. Multi-player games on the cycle

    PubMed Central

    van Veelen, Matthijs; Nowak, Martin

    2011-01-01

    In multi-player games n individuals interact in any one encounter and derive a payoff from that interaction. We assume that individuals adopt one of two strategies, and we consider symmetric games, which means the payoff depends only on the number of players using either strategy, but not on any particular configuration of the encounter. On the cycle we assume that any string of n neighbouring players interacts. We study fixation probabilities of stochastic evolutionary dynamics. We derive analytical results on the cycle both for linear and exponential fitness for any intensity of selection, and compare those to results for the well-mixed population. As particular examples we study multi-player public goods games, stag hunt games and snowdrift games. PMID:21907215

  8. Stochastic Cooling

    SciTech Connect

    Blaskiewicz, M.

    2011-01-01

    Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

  9. Game On!

    ERIC Educational Resources Information Center

    Deubel, Patricia

    2006-01-01

    This article describes digital game-based learning (DGBL), the uniting of educational content with computer or online games, that holds the potential for a wealth of educational applications, if managed properly. DGBL motivates by virtue of being fun. It is versatile, can be used to teach almost any subject or skill, and, when used correctly, is

  10. Fun & Games

    ERIC Educational Resources Information Center

    Jacobs, Amy; Kohl, Julie

    2007-01-01

    This article discusses how math skills, teamwork and higher-level thinking come together when students create strategic board games. In this article, the authors provide a glimpse of what it was like to be part of "To the Sun!," a game designed by students in the fifth-grade class at Olive Martin School in Lake Villa, IL. Students combined a math…

  11. Game Time!

    ERIC Educational Resources Information Center

    Marek, Edmund; Howell, Beverly

    2006-01-01

    In this article, the authors present a classic playground game called "Sharks and Fishes" to introduce second- to fourth-grade students to the concept of "predation," or the relationships between a predator and its prey. By incorporating the game in a learning cycle on predation, students not only learn about predation in a memorable way, but they

  12. Fun & Games

    ERIC Educational Resources Information Center

    Jacobs, Amy; Kohl, Julie

    2007-01-01

    This article discusses how math skills, teamwork and higher-level thinking come together when students create strategic board games. In this article, the authors provide a glimpse of what it was like to be part of "To the Sun!," a game designed by students in the fifth-grade class at Olive Martin School in Lake Villa, IL. Students combined a math

  13. Epistemic Games

    ERIC Educational Resources Information Center

    Shaffer, David Williamson

    2005-01-01

    In an article in this issue of "Innovate", Jim Gee asks the question "What would a state of the art instructional video game look like?" Based on the game "Full Spectrum Warrior", he concludes that one model is "to pick [a] domain of authentic professionalism well, intelligently select the skills and knowledge to be distributed, build in a related

  14. Literature Games.

    ERIC Educational Resources Information Center

    Van Scoy, Karen; Whitehead, Robert

    The primary purpose of this book is to make available to teachers and children a significant number of interesting game activities that will enrich the entire reading program, especially the literature portion. The games are designed primarily for use in two portions of the reading program: (1) the "enrichment reading program," and (2) the

  15. Noise-induced switches in network systems of the genetic toggle switch

    PubMed Central

    Wang, Junwei; Zhang, Jiajun; Yuan, Zhanjiang; Zhou, Tianshou

    2007-01-01

    Background Bistability, the capacity to achieve two distinct stable steady states in response to a set of external stimuli, arises within biological systems ranging from the ? phage switch in bacteria to cellular signal transduction pathways in mammalian cells. On the other hand, more and more experimental evidence in the form of bimodal population distribution has indicated that noise plays a very important role in the switching of bistable systems. However, the physiological mechanism underling noise-induced switching behaviors remains to be fully understood. Results In this paper, we investigate the effect of noises on switching in single and coupled genetic toggle switch systems in Escherichia coli. In the case of the single toggle switch, we show that the multiplicative noises resulting from stochastic fluctuations in degradation rates can induce switching. In the case of the toggle switches interfaced by a quorum-sensing signaling pathway, we find that stochastic fluctuations in degradation rates inside cells, i.e., intracellular noises, can induce synchronized switching, whereas the extracellular noise additive to the common medium can not only entrain all the individual systems to switch in a synchronous manner but also enhance this ordering behavior efficiently, leading a robust collective rhythm in this interacting system. Conclusion These insights on the effect of noises would be beneficial to understanding the basic mechanism of how living systems optimally facilitate to function under various fluctuated environments. PMID:18005421

  16. Game Over?

    NASA Astrophysics Data System (ADS)

    Harteveld, Casper

    This level marks the ending of the book. After comparing the game design process to a children's book about designing a butterfly, it goes into how a balance is found when designing a game. To explain this, an analogy is made with the concept of Yin and Yang. This level further deals with the so what and who cares question of the Triadic Game Design (TGD) approach. It is concluded that it can be used as an analytical lens, application tool, or puzzle frame in the field of games. But to have a real impact on the actual practice, it is needed that people are familiar with the idea of TGD. Since game design is (generally) collaborative, it would be beneficial that more than one person knows about it. For this reason, a game-based workshop has been developed that can be employed at the beginning of a project. Besides making sure that a project runs smoothly during the design, considerations should also be made about what happens if the game is finished. From the observations of the life after the design it becomes clear that this is certainly an issue that should not be neglected. The main message of this level concerns, however, that although this book is game over, it is everything but over for the design and research of games. To bring the field to the next level, structural approaches are needed and TGD is one of them. With the insights of this approach in mind, people can start to dance. Because it takes two to tango, but it takes three to design a game with a meaningful purpose.

  17. Stochastic effects in a seasonally forced epidemic model

    NASA Astrophysics Data System (ADS)

    Rozhnova, G.; Nunes, A.

    2010-10-01

    The interplay of seasonality, the system’s nonlinearities and intrinsic stochasticity, is studied for a seasonally forced susceptible-exposed-infective-recovered stochastic model. The model is explored in the parameter region that corresponds to childhood infectious diseases such as measles. The power spectrum of the stochastic fluctuations around the attractors of the deterministic system that describes the model in the thermodynamic limit is computed analytically and validated by stochastic simulations for large system sizes. Size effects are studied through additional simulations. Other effects such as switching between coexisting attractors induced by stochasticity often mentioned in the literature as playing an important role in the dynamics of childhood infectious diseases are also investigated. The main conclusion is that stochastic amplification, rather than these effects, is the key ingredient to understand the observed incidence patterns.

  18. Optical switches and switching methods

    DOEpatents

    Doty, Michael

    2008-03-04

    A device and method for collecting subject responses, particularly during magnetic imaging experiments and testing using a method such as functional MRI. The device comprises a non-metallic input device which is coupled via fiber optic cables to a computer or other data collection device. One or more optical switches transmit the subject's responses. The input device keeps the subject's fingers comfortably aligned with the switches by partially immobilizing the forearm, wrist, and/or hand of the subject. Also a robust nonmetallic switch, particularly for use with the input device and methods for optical switching.

  19. Stochastic memristive devices for computing and neuromorphic applications.

    PubMed

    Gaba, Siddharth; Sheridan, Patrick; Zhou, Jiantao; Choi, Shinhyun; Lu, Wei

    2013-07-01

    Nanoscale resistive switching devices (memristive devices or memristors) have been studied for a number of applications ranging from non-volatile memory, logic to neuromorphic systems. However a major challenge is to address the potentially large variations in space and time in these nanoscale devices. Here we show that in metal-filament based memristive devices the switching can be fully stochastic. While individual switching events are random, the distribution and probability of switching can be well predicted and controlled. Rather than trying to force high switching probabilities using excess voltage or time, the inherent stochastic nature of resistive switching allows these binary devices to be used as building blocks for novel error-tolerant computing schemes such as stochastic computing and provides the needed "analog" feature for neuromorphic applications. To verify such potential, we demonstrated memristor-based stochastic bitstreams in both time and space domains, and show that an array of binary memristors can act as a multi-level "analog" device for neuromorphic applications. PMID:23698627

  20. Stochastic memristive devices for computing and neuromorphic applications

    NASA Astrophysics Data System (ADS)

    Gaba, Siddharth; Sheridan, Patrick; Zhou, Jiantao; Choi, Shinhyun; Lu, Wei

    2013-06-01

    Nanoscale resistive switching devices (memristive devices or memristors) have been studied for a number of applications ranging from non-volatile memory, logic to neuromorphic systems. However a major challenge is to address the potentially large variations in space and time in these nanoscale devices. Here we show that in metal-filament based memristive devices the switching can be fully stochastic. While individual switching events are random, the distribution and probability of switching can be well predicted and controlled. Rather than trying to force high switching probabilities using excess voltage or time, the inherent stochastic nature of resistive switching allows these binary devices to be used as building blocks for novel error-tolerant computing schemes such as stochastic computing and provides the needed ``analog'' feature for neuromorphic applications. To verify such potential, we demonstrated memristor-based stochastic bitstreams in both time and space domains, and show that an array of binary memristors can act as a multi-level ``analog'' device for neuromorphic applications.

  1. ION SWITCH

    DOEpatents

    Cook, B.

    1959-02-10

    An ion switch capable of transferring large magnitudes of power is described. An ion switch constructed in accordance with the invention includes a pair of spaced control electrodes disposed in a highly evacuated region for connection in a conventional circuit to control the passing of power therethrough. A controllable ionic conduction path is provided directiy between the control electrodes by a source unit to close the ion switch. Conventional power supply means are provided to trigger the source unit and control the magnitude, durations and pulse repetition rate of the aforementioned ionic conduction path.

  2. Night Games.

    ERIC Educational Resources Information Center

    Steinbach, Paul

    2001-01-01

    Discusses how to control sports facility outdoor lighting during night games. Different lighting techniques are explored for keeping lighting inside the stadium and not disturb the surrounding community. (GR)

  3. Game Proof.

    ERIC Educational Resources Information Center

    Mitchell, John

    1980-01-01

    The author argues that adult society prohibits adolescents from attaining maturity and that, in response to such constraints, adolescents turn to games, rituals, and charades. This state of affairs is viewed as an implicit adult conspiracy against adolescents. (DB)

  4. Stochastic learning in oxide binary synaptic device for neuromorphic computing

    PubMed Central

    Yu, Shimeng; Gao, Bin; Fang, Zheng; Yu, Hongyu; Kang, Jinfeng; Wong, H.-S. Philip

    2013-01-01

    Hardware implementation of neuromorphic computing is attractive as a computing paradigm beyond the conventional digital computing. In this work, we show that the SET (off-to-on) transition of metal oxide resistive switching memory becomes probabilistic under a weak programming condition. The switching variability of the binary synaptic device implements a stochastic learning rule. Such stochastic SET transition was statistically measured and modeled for a simulation of a winner-take-all network for competitive learning. The simulation illustrates that with such stochastic learning, the orientation classification function of input patterns can be effectively realized. The system performance metrics were compared between the conventional approach using the analog synapse and the approach in this work that employs the binary synapse utilizing the stochastic learning. The feasibility of using binary synapse in the neurormorphic computing may relax the constraints to engineer continuous multilevel intermediate states and widens the material choice for the synaptic device design. PMID:24198752

  5. Steady-state simulation of metastable stochastic chemical systems

    NASA Astrophysics Data System (ADS)

    Milias-Argeitis, Andreas; Lygeros, John

    2013-05-01

    We address the problem of steady-state simulation for metastable continuous-time Markov chains with application to stochastic chemical kinetics. Such systems are characterized by the existence of two or more pseudo-equilibrium states and very slow convergence towards global equilibrium. Approximation of the stationary distribution of these systems by direct application of the Stochastic Simulation Algorithm (SSA) is known to be very inefficient. In this paper, we propose a new method for steady-state simulation of metastable Markov chains that is centered around the concept of stochastic complementation. The use of this mathematical device along with SSA results in an algorithm with much better convergence properties, that facilitates the analysis of rarely switching stochastic biochemical systems. The efficiency of our method is demonstrated by its application to two genetic toggle switch models.

  6. Stochastic learning in oxide binary synaptic device for neuromorphic computing.

    PubMed

    Yu, Shimeng; Gao, Bin; Fang, Zheng; Yu, Hongyu; Kang, Jinfeng; Wong, H-S Philip

    2013-01-01

    Hardware implementation of neuromorphic computing is attractive as a computing paradigm beyond the conventional digital computing. In this work, we show that the SET (off-to-on) transition of metal oxide resistive switching memory becomes probabilistic under a weak programming condition. The switching variability of the binary synaptic device implements a stochastic learning rule. Such stochastic SET transition was statistically measured and modeled for a simulation of a winner-take-all network for competitive learning. The simulation illustrates that with such stochastic learning, the orientation classification function of input patterns can be effectively realized. The system performance metrics were compared between the conventional approach using the analog synapse and the approach in this work that employs the binary synapse utilizing the stochastic learning. The feasibility of using binary synapse in the neurormorphic computing may relax the constraints to engineer continuous multilevel intermediate states and widens the material choice for the synaptic device design. PMID:24198752

  7. Computer Game

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Using NASA studies of advanced lunar exploration and colonization, KDT Industries, Inc. and Wesson International have developed MOONBASE, a computer game. The player, or team commander, must build and operate a lunar base using NASA technology. He has 10 years to explore the surface, select a site and assemble structures brought from Earth into an efficient base. The game was introduced in 1991 by Texas Space Grant Consortium.

  8. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P. (Albuquerque, NM); Devaney, Howard F. (Cedar Crest, NM); Hake, Lewis W. (Albuquerque, NM)

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  9. Donor Tag Game

    MedlinePLUS

    ... Games > Donor Tag Game Printable Version Donor Tag Game This feature requires version 6 or later of ... of Needles Blood Donor Community Real Stories SleevesUp Games Facebook Fanbox Avatars and Badges Banners eCards Enter ...

  10. Models of Games Education.

    ERIC Educational Resources Information Center

    Werner, Peter; Almond, Len

    1990-01-01

    Physical educators should be selective in deciding what games to include in the games curriculum. Several theoretical frameworks for selecting and teaching games are discussed, and a framework for developing a well-balanced games program is suggested. (IAH)

  11. Game playing.

    PubMed

    Rosin, Christopher D

    2014-03-01

    Game playing has been a core domain of artificial intelligence research since the beginnings of the field. Game playing provides clearly defined arenas within which computational approaches can be readily compared to human expertise through head-to-head competition and other benchmarks. Game playing research has identified several simple core algorithms that provide successful foundations, with development focused on the challenges of defeating human experts in specific games. Key developments include minimax search in chess, machine learning from self-play in backgammon, and Monte Carlo tree search in Go. These approaches have generalized successfully to additional games. While computers have surpassed human expertise in a wide variety of games, open challenges remain and research focuses on identifying and developing new successful algorithmic foundations. WIREs Cogn Sci 2014, 5:193-205. doi: 10.1002/wcs.1278 CONFLICT OF INTEREST: The author has declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. PMID:26304308

  12. Life-Game, with Glass Beads and Molecules, on the Principles of the Origin of Life

    ERIC Educational Resources Information Center

    Eigen, Manfred; Haglund, Herman

    1976-01-01

    Discusses a theoretical model that uses a game as a base for studying processes of a stochastic nature, which involve chemical reactions, molecular systems, biological processes, cells, or people in a population. (MLH)

  13. Linear System Control Using Stochastic Learning Automata

    NASA Technical Reports Server (NTRS)

    Ziyad, Nigel; Cox, E. Lucien; Chouikha, Mohamed F.

    1998-01-01

    This paper explains the use of a Stochastic Learning Automata (SLA) to control switching between three systems to produce the desired output response. The SLA learns the optimal choice of the damping ratio for each system to achieve a desired result. We show that the SLA can learn these states for the control of an unknown system with the proper choice of the error criteria. The results of using a single automaton are compared to using multiple automata.

  14. Computer Games and Instruction

    ERIC Educational Resources Information Center

    Tobias, Sigmund, Ed.; Fletcher, J. D., Ed.

    2011-01-01

    There is intense interest in computer games. A total of 65 percent of all American households play computer games, and sales of such games increased 22.9 percent last year. The average amount of game playing time was found to be 13.2 hours per week. The popularity and market success of games is evident from both the increased earnings from games,

  15. Nanoscale resistive switching devices: mechanisms and modeling.

    PubMed

    Yang, Yuchao; Lu, Wei

    2013-11-01

    Resistive switching devices (also termed memristive devices or memristors) are two-terminal nonlinear dynamic electronic devices that can have broad applications in the fields of nonvolatile memory, reconfigurable logic, analog circuits, and neuromorphic computing. Current rapid advances in memristive devices in turn demand better understanding of the switching mechanism and the development of physics-based as well as simplified device models to guide future device designs and circuit-level applications. In this article, we review the physical processes behind resistive switching (memristive) phenomena and discuss the experimental and modeling efforts to explain these effects. In this article three categories of devices, in which the resistive switching effects are driven by cation migration, anion migration, and electronic effects, will be discussed. The fundamental driving forces and the stochastic nature of resistive switching will also be discussed. PMID:24057010

  16. Nanoscale resistive switching devices: mechanisms and modeling

    NASA Astrophysics Data System (ADS)

    Yang, Yuchao; Lu, Wei

    2013-10-01

    Resistive switching devices (also termed memristive devices or memristors) are two-terminal nonlinear dynamic electronic devices that can have broad applications in the fields of nonvolatile memory, reconfigurable logic, analog circuits, and neuromorphic computing. Current rapid advances in memristive devices in turn demand better understanding of the switching mechanism and the development of physics-based as well as simplified device models to guide future device designs and circuit-level applications. In this article, we review the physical processes behind resistive switching (memristive) phenomena and discuss the experimental and modeling efforts to explain these effects. In this article three categories of devices, in which the resistive switching effects are driven by cation migration, anion migration, and electronic effects, will be discussed. The fundamental driving forces and the stochastic nature of resistive switching will also be discussed.

  17. Stochastic cooling in RHIC

    SciTech Connect

    Brennan,J.M.; Blaskiewicz, M. M.; Severino, F.

    2009-05-04

    After the success of longitudinal stochastic cooling of bunched heavy ion beam in RHIC, transverse stochastic cooling in the vertical plane of Yellow ring was installed and is being commissioned with proton beam. This report presents the status of the effort and gives an estimate, based on simulation, of the RHIC luminosity with stochastic cooling in all planes.

  18. The Switch Task for Children: Measuring Mental Flexibility in Young Children

    ERIC Educational Resources Information Center

    Dibbets, Pauline; Jolles, Jellemer

    2006-01-01

    Age-related changes in mental flexibility, in the form of task switching, were assessed in 292 children (58-156 months old). Task switching was examined with a new task for young children, the Switch Task for Children (STC). The STC consists of two easy, comparable games and does not require reading skills, which makes it suitable for children

  19. Stochastic memristive nature in Co-doped CeO{sub 2} nanorod arrays

    SciTech Connect

    Younis, Adnan; Chu, Dewei Li, Sean

    2013-12-16

    In this Letter, bipolar resistive switching characteristics of electrochemically deposited pure and Cobalt doped CeO{sub 2} nanorods architectures were reported. A conducting filament based model to address resistive switching process in these devices was proposed. Furthermore, the randomness in individual switching events and the prediction of switching probabilities were studied by imposing weak programming conditions. The present study offers insights into scrutinize the inherent stochastic nature in resistive switching characteristics within these devices rather than stressfully achieve high switching probabilities using excess voltage or time.

  20. Optical switch

    DOEpatents

    Reedy, R.P.

    1985-01-18

    An optical switching device is provided whereby light from a first glass fiber or a second glass fiber may be selectively transmitted into a third glass fiber. Each glass fiber is provided with a focusing and collimating lens system. In one mode of operation, light from the first glass fiber is reflected by a planar mirror into the third glass fiber. In another mode of operation, light from the second glass fiber passes directly into the third glass fiber. The planar mirror is attached to a rotatable table which is rotated to provide the optical switching.

  1. Optical switch

    DOEpatents

    Reedy, Robert P. (Livermore, CA)

    1987-01-01

    An optical switching device (10) is provided whereby light from a first glass fiber (16) or a second glass fiber (14) may be selectively transmitted into a third glass fiber (18). Each glass fiber is provided with a focusing and collimating lens system (26, 28, 30). In one mode of operation, light from the first glass fiber (16) is reflected by a planar mirror (36) into the third glass fiber (18). In another mode of operation, light from the second glass fiber (14) passes directly into the third glass fiber (18). The planar mirror (36) is attached to a rotatable table (32) which is rotated to provide the optical switching.

  2. Optical switch

    DOEpatents

    Reedy, R.P.

    1987-11-10

    An optical switching device is provided whereby light from a first glass fiber or a second glass fiber may be selectively transmitted into a third glass fiber. Each glass fiber is provided with a focusing and collimating lens system. In one mode of operation, light from the first glass fiber is reflected by a planar mirror into the third glass fiber. In another mode of operation, light from the second glass fiber passes directly into the third glass fiber. The planar mirror is attached to a rotatable table which is rotated to provide the optical switching. 3 figs.

  3. Comparison of approaches for parameter estimation on stochastic models: Generic least squares versus specialized approaches.

    PubMed

    Zimmer, Christoph; Sahle, Sven

    2016-04-01

    Parameter estimation for models with intrinsic stochasticity poses specific challenges that do not exist for deterministic models. Therefore, specialized numerical methods for parameter estimation in stochastic models have been developed. Here, we study whether dedicated algorithms for stochastic models are indeed superior to the naive approach of applying the readily available least squares algorithm designed for deterministic models. We compare the performance of the recently developed multiple shooting for stochastic systems (MSS) method designed for parameter estimation in stochastic models, a stochastic differential equations based Bayesian approach and a chemical master equation based techniques with the least squares approach for parameter estimation in models of ordinary differential equations (ODE). As test data, 1000 realizations of the stochastic models are simulated. For each realization an estimation is performed with each method, resulting in 1000 estimates for each approach. These are compared with respect to their deviation to the true parameter and, for the genetic toggle switch, also their ability to reproduce the symmetry of the switching behavior. Results are shown for different set of parameter values of a genetic toggle switch leading to symmetric and asymmetric switching behavior as well as an immigration-death and a susceptible-infected-recovered model. This comparison shows that it is important to choose a parameter estimation technique that can treat intrinsic stochasticity and that the specific choice of this algorithm shows only minor performance differences. PMID:26826353

  4. Serious Games: Video Games for Good?

    ERIC Educational Resources Information Center

    Sanford, Kathy; Starr, Lisa J.; Merkel, Liz; Bonsor Kurki, Sarah

    2015-01-01

    As video games become a ubiquitous part of today's culture internationally, as educators and parents we need to turn our attention to how video games are being understood and used in informal and formal settings. Serious games have developed as a genre of video games marketed for educating youth about a range of world issues. At face value this…

  5. Are You Game for a Game?

    ERIC Educational Resources Information Center

    McKnight, Regis Q.; Harnapp, Vern

    1979-01-01

    Describes a game construction model which can be applied to an instructional game or a simulation game for elementary and junior high social studies classes. The game deals with motivations and hardships of the Pilgrims as they traveled to the New World. Journal availability: see SO 507 149. (Author/DB)

  6. Serious Games: Video Games for Good?

    ERIC Educational Resources Information Center

    Sanford, Kathy; Starr, Lisa J.; Merkel, Liz; Bonsor Kurki, Sarah

    2015-01-01

    As video games become a ubiquitous part of today's culture internationally, as educators and parents we need to turn our attention to how video games are being understood and used in informal and formal settings. Serious games have developed as a genre of video games marketed for educating youth about a range of world issues. At face value this

  7. Switching Transistor

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Westinghouse Electric Corporation's D60T transistors are used primarily as switching devices for controlling high power in electrical circuits. It enables reduction in the number and size of circuit components and promotes more efficient use of energy. Wide range of application from a popcorn popper to a radio frequency generator for solar cell production.

  8. Switched power workshop. [Switched power electron guns

    SciTech Connect

    Palmer, R.B.

    1988-01-01

    This paper discusses the design of a switched power electron gun. Particular topics discussed are: vacuum photodiode switch; laser switched solid state diodes; gun performance; charging supply; and laser requirements. (LSP)

  9. Night Games.

    ERIC Educational Resources Information Center

    Jefferson, Bob; Hall, Jan D.

    1992-01-01

    Installation of a new metal halide lighting system at an old athletic high school stadium serving the Red Lion School District in Pennsylvania made night games possible. Community members raised funds for the installation. Because of increased attendance, the district made a $10,000 profit. Provides facts and figures on the stadium lighting. (MLF)

  10. Got Game

    ERIC Educational Resources Information Center

    Lum, Lydia

    2007-01-01

    Around the country, disabled sports are often treated like second-class siblings to their able-bodied counterparts, largely because the latter bring in prestigious tournaments and bowl games, lucrative TV contracts and national exposure for top athletes and coaches. Because disabled people are so sparsely distributed in the general population, it…

  11. Evil games.

    PubMed

    Chambers, David W

    2010-01-01

    A defining characteristic of humans is our capacity to create a better world through mutual action. Traditional ethics attempts to define and impose the one or several things we should all want. The alternative argued here is that we can retain our individual definitions of what matters and still work together for mutual improvement. Agreeing on common ethical principles is not a precondition for an effective moral life. This approach to morality is based on game theory, which holds that in purposely social interactions: (a) there are basic understandings, (b) individuals pursue their own interests, (c) we can judge others' interests, and (d) the distribution of benefits and burdens depends on the joint action of individuals, not on the action of individuals in isolation. In this view, immorality becomes a matter of cheating in the game of life. The three primary forms of cheating are deception (misleading others into thinking they are playing a game other than the one that is to their advantage to play), coercion (blocking courses of action others would normally be entitled to), and reneging (playing the game and then dodging the payoff if one does not like the outcome). These three evils are illustrated by Shakespeare's plays Othello, Richard III, and Antony and Cleopatra. PMID:20481069

  12. Library Games.

    ERIC Educational Resources Information Center

    Portland Public Schools, OR. Dept. of Educational Media.

    The learning activities collected here are designed to reinforce library skills and to make the library a more attractive place to public school students. Included are ideas for bulletin boards, crossword puzzles, matching games, treasure hunts, and find-the-word puzzles. (Author/PF)

  13. Art Games.

    ERIC Educational Resources Information Center

    Bishop, Bobbi

    1978-01-01

    What do you do with 100 or more children who would rather be in a warm art room than outside on the cold playground for 45 minutes at noon? The solution, games: to arouse interest, to teach basic art principles, and to reinforce art concepts. (Author/RK)

  14. Math Games

    ERIC Educational Resources Information Center

    Lorenzi, Natalie

    2012-01-01

    Math games bring out kids' natural love of numbers. Yet in the waning days of school, students can't wait for that final bell to ring. Each summer, most students lose about two months of mathematical computation skills. So how do teachers keep their students focused on math up till the end? Before sending them off for the summer, get them hooked…

  15. Got Game

    ERIC Educational Resources Information Center

    Lum, Lydia

    2007-01-01

    Around the country, disabled sports are often treated like second-class siblings to their able-bodied counterparts, largely because the latter bring in prestigious tournaments and bowl games, lucrative TV contracts and national exposure for top athletes and coaches. Because disabled people are so sparsely distributed in the general population, it

  16. Grammar Games

    ERIC Educational Resources Information Center

    Brown, Kim

    2004-01-01

    The mere mention of a grammar lesson can set students' eyes rolling. The fun activities described in this article can turn those blank looks into smiles. Here, the author presents grammar games namely: (1) noun tennis; (2) the minister's cat; (3) kids take action; (4) what's my adverb?; (5) and then I saw...; and (6) grammar sing-along.

  17. Shell Games.

    ERIC Educational Resources Information Center

    Atkinson, Bill

    1982-01-01

    The author critiques the program design and educational aspects of the Shell Games, a program developed by Apple Computer, Inc., which can be used by the teacher to design objective tests for adaptation to specific assessment needs. (For related articles, see EC 142 959-962.) (Author)

  18. Stochastic resonance in attention control

    NASA Astrophysics Data System (ADS)

    Kitajo, K.; Yamanaka, K.; Ward, L. M.; Yamamoto, Y.

    2006-12-01

    We investigated the beneficial role of noise in a human higher brain function, namely visual attention control. We asked subjects to detect a weak gray-level target inside a marker box either in the left or the right visual field. Signal detection performance was optimized by presenting a low level of randomly flickering gray-level noise between and outside the two possible target locations. Further, we found that an increase in eye movement (saccade) rate helped to compensate for the usual deterioration in detection performance at higher noise levels. To our knowledge, this is the first experimental evidence that noise can optimize a higher brain function which involves distinct brain regions above the level of primary sensory systems -- switching behavior between multi-stable attention states -- via the mechanism of stochastic resonance.

  19. Teaching Using Computer Games

    ERIC Educational Resources Information Center

    Miller, Lee Dee; Shell, Duane; Khandaker, Nobel; Soh, Leen-Kiat

    2011-01-01

    Computer games have long been used for teaching. Current reviews lack categorization and analysis using learning models which would help instructors assess the usefulness of computer games. We divide the use of games into two classes: game playing and game development. We discuss the Input-Process-Outcome (IPO) model for the learning process when…

  20. Games and Learning

    ERIC Educational Resources Information Center

    Oblinger, Diana G.

    2006-01-01

    From a very early age, people learn from games and play. Parents and preschool teachers use games to teach colors, numbers, names, and shapes; the process is drill and practice. Games engage everyone, capturing their attention. People willingly spend time on task. Although students in high school and college continue to play games, games rarely…

  1. Teaching Using Computer Games

    ERIC Educational Resources Information Center

    Miller, Lee Dee; Shell, Duane; Khandaker, Nobel; Soh, Leen-Kiat

    2011-01-01

    Computer games have long been used for teaching. Current reviews lack categorization and analysis using learning models which would help instructors assess the usefulness of computer games. We divide the use of games into two classes: game playing and game development. We discuss the Input-Process-Outcome (IPO) model for the learning process when

  2. Games and Learning

    ERIC Educational Resources Information Center

    Oblinger, Diana G.

    2006-01-01

    From a very early age, people learn from games and play. Parents and preschool teachers use games to teach colors, numbers, names, and shapes; the process is drill and practice. Games engage everyone, capturing their attention. People willingly spend time on task. Although students in high school and college continue to play games, games rarely

  3. Video game use and cognitive performance: does it vary with the presence of problematic video game use?

    PubMed

    Collins, Emily; Freeman, Jonathan

    2014-03-01

    Action video game players have been found to outperform nonplayers on a variety of cognitive tasks. However, several failures to replicate these video game player advantages have indicated that this relationship may not be straightforward. Moreover, despite the discovery that problematic video game players do not appear to demonstrate the same superior performance as nonproblematic video game players in relation to multiple object tracking paradigms, this has not been investigated for other tasks. Consequently, this study compared gamers and nongamers in task switching ability, visual short-term memory, mental rotation, enumeration, and flanker interference, as well as investigated the influence of self-reported problematic video game use. A total of 66 participants completed the experiment, 26 of whom played action video games, including 20 problematic players. The results revealed no significant effect of playing action video games, nor any influence of problematic video game play. This indicates that the previously reported cognitive advantages in video game players may be restricted to specific task features or samples. Furthermore, problematic video game play may not have a detrimental effect on cognitive performance, although this is difficult to ascertain considering the lack of video game player advantage. More research is therefore sorely needed. PMID:24111600

  4. Play the MRI Game

    MedlinePLUS

    ... Teachers' Questionnaire MRI Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  5. Play the Electrocardiogram Game

    MedlinePLUS

    ... and Work Teachers' Questionnaire Electrocardiogram Play the ECG Game About the game ECG is used for diagnosing heart conditions by ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  6. The Green Revolution Game.

    ERIC Educational Resources Information Center

    Corbridge, Stuart

    1985-01-01

    The Green Revolution game helps college students learn about agrarian change in which people use science to transform nature. The rational and basic objectives of the game are discussed, and the game's strengths and weaknesses are examined. (RM)

  7. Structure-preserving desynchronization of minority games

    NASA Astrophysics Data System (ADS)

    Mosetti, G.; Challet, D.; Solomon, S.

    2009-10-01

    Perfect synchronicity in N-player games is a useful theoretical dream, but communication delays are inevitable and may result in asynchronous interactions. Some systems such as financial markets are asynchronous by design, and yet most theoretical models assume perfectly synchronized actions. We propose a general method to transform standard models of adaptive agents into asynchronous systems while preserving their global structure under some conditions. Using the minority game as an example, we find that the phase and fluctuations structure of the standard game subsists even in maximally asynchronous deterministic case, but that it disappears if too much stochasticity is added to the temporal structure of interaction. Allowing for heterogeneous communication speeds and activity patterns gives rise to a new information ecology that we study in details. in here

  8. Obliging Games

    NASA Astrophysics Data System (ADS)

    Chatterjee, Krishnendu; Horn, Florian; Lding, Christof

    Graph games of infinite length provide a natural model for open reactive systems: one player (Eve) represents the controller and the other player (Adam) represents the environment. The evolution of the system depends on the decisions of both players. The specification for the system is usually given as an ?-regular language L over paths and Eve's goal is to ensure that the play belongs to L irrespective of Adam's behaviour.

  9. Computer Games and Instruction

    ERIC Educational Resources Information Center

    Tobias, Sigmund, Ed.; Fletcher, J. D., Ed.

    2011-01-01

    There is intense interest in computer games. A total of 65 percent of all American households play computer games, and sales of such games increased 22.9 percent last year. The average amount of game playing time was found to be 13.2 hours per week. The popularity and market success of games is evident from both the increased earnings from games,…

  10. Motivational Correlations of Strategy Choices in the Prisoner's Dilemma Game

    NASA Technical Reports Server (NTRS)

    Williams, Carl D.; Steele, Matthew W.; Tedeschi, James T.

    1969-01-01

    The purpose of the present study was to investigate the relationship between the motivational dimensions assessed by the Motivation Analysis Test and prisoner's dilemma game behavior as measured both by the number of competitive strategy choices and the two-stage stochastic variables labelled trustworthiness, forgiveness, repentance, and trust by Rapoport.

  11. Stochastic Convection Parameterizations

    NASA Technical Reports Server (NTRS)

    Teixeira, Joao; Reynolds, Carolyn; Suselj, Kay; Matheou, Georgios

    2012-01-01

    computational fluid dynamics, radiation, clouds, turbulence, convection, gravity waves, surface interaction, radiation interaction, cloud and aerosol microphysics, complexity (vegetation, biogeochemistry, radiation versus turbulence/convection stochastic approach, non-linearities, Monte Carlo, high resolutions, large-Eddy Simulations, cloud structure, plumes, saturation in tropics, forecasting, parameterizations, stochastic, radiation-clod interaction, hurricane forecasts

  12. A Stochastic Employment Problem

    ERIC Educational Resources Information Center

    Wu, Teng

    2013-01-01

    The Stochastic Employment Problem(SEP) is a variation of the Stochastic Assignment Problem which analyzes the scenario that one assigns balls into boxes. Balls arrive sequentially with each one having a binary vector X = (X[subscript 1], X[subscript 2],...,X[subscript n]) attached, with the interpretation being that if X[subscript i] = 1 the ball

  13. Path sampling with stochastic dynamics: Some new algorithms

    SciTech Connect

    Stoltz, Gabriel . E-mail: stoltz@cermics.enpc.fr

    2007-07-01

    We propose here some new sampling algorithms for path sampling in the case when stochastic dynamics are used. In particular, we present a new proposal function for equilibrium sampling of paths with a Monte-Carlo dynamics (the so-called 'brownian tube' proposal). This proposal is based on the continuity of the dynamics with respect to the random forcing, and generalizes all previous approaches when stochastic dynamics are used. The efficiency of this proposal is demonstrated using some measure of decorrelation in path space. We also discuss a switching strategy that allows to transform ensemble of paths at a finite rate while remaining at equilibrium, in contrast with the usual Jarzynski like switching. This switching is very interesting to sample constrained paths starting from unconstrained paths, or to perform simulated annealing in a rigorous way.

  14. Viscosity Solutions of Systems of PDEs with Interconnected Obstacles and Switching Problem

    SciTech Connect

    Hamadene, S. Morlais, M. A.

    2013-04-15

    This paper deals with existence and uniqueness of a solution in viscosity sense, for a system of m variational partial differential inequalities with inter-connected obstacles. A particular case is the Hamilton-Jacobi-Bellmann system of the Markovian stochastic optimal m-states switching problem. The switching cost functions depend on (t,x). The main tool is the notion of systems of reflected backward stochastic differential equations with oblique reflection.

  15. Deterministic characterization of stochastic genetic circuits

    PubMed Central

    Scott, Matthew; Hwa, Terence; Ingalls, Brian

    2007-01-01

    For cellular biochemical reaction systems where the numbers of molecules is small, significant noise is associated with chemical reaction events. This molecular noise can give rise to behavior that is very different from the predictions of deterministic rate equation models. Unfortunately, there are few analytic methods for examining the qualitative behavior of stochastic systems. Here we describe such a method that extends deterministic analysis to include leading-order corrections due to the molecular noise. The method allows the steady-state behavior of the stochastic model to be easily computed, facilitates the mapping of stability phase diagrams that include stochastic effects, and reveals how model parameters affect noise susceptibility in a manner not accessible to numerical simulation. By way of illustration we consider two genetic circuits: a bistable positive-feedback loop and a negative-feedback oscillator. We find in the positive feedback circuit that translational activation leads to a far more stable system than transcriptional control. Conversely, in a negative-feedback loop triggered by a positive-feedback switch, the stochasticity of transcriptional control is harnessed to generate reproducible oscillations. PMID:17446275

  16. Stabilized multilevel Monte Carlo method for stiff stochastic differential equations

    SciTech Connect

    Abdulle, Assyr Blumenthal, Adrian

    2013-10-15

    A multilevel Monte Carlo (MLMC) method for mean square stable stochastic differential equations with multiple scales is proposed. For such problems, that we call stiff, the performance of MLMC methods based on classical explicit methods deteriorates because of the time step restriction to resolve the fastest scales that prevents to exploit all the levels of the MLMC approach. We show that by switching to explicit stabilized stochastic methods and balancing the stabilization procedure simultaneously with the hierarchical sampling strategy of MLMC methods, the computational cost for stiff systems is significantly reduced, while keeping the computational algorithm fully explicit and easy to implement. Numerical experiments on linear and nonlinear stochastic differential equations and on a stochastic partial differential equation illustrate the performance of the stabilized MLMC method and corroborate our theoretical findings.

  17. Transcription Stochasticity of Complex Gene Regulation Models

    PubMed Central

    Schwabe, Anne; Rybakova, KatjaN.; Bruggeman, FrankJ.

    2012-01-01

    Transcription is regulated by a multitude of factors that concertedly induce genes to switch between activity states. Eukaryotic transcription involves a multitude of complexes that sequentially assemble on chromatin under the influence of transcription factors and the dynamic state of chromatin. Prokaryotic transcription depends on transcription factors, sigma-factors, and, in some cases, on DNA looping. We present a stochastic model of transcription that considers these complex regulatory mechanisms. We coarse-grain the molecular details in such a way that the model can describe a broad class of gene-regulation mechanisms. We solve this model analytically for various measures of stochastic transcription and compare alternative gene-regulation designs. We find that genes with complex multiprotein regulation can have peaked burst-size distributions in contrast to the geometric distributions found for simple models of transcription regulation. Burst-size distributions are, in addition, shaped by mRNA degradation during transcription bursts. We derive the stochastic properties of genes in the limit of deterministic switch times. These genes typically have reduced transcription noise. Severe timescale separation between gene regulation and transcription initiation enhances noise and leads to bimodal mRNA copy number distributions. In general, complex mechanisms for gene regulation lead to nonexponential waiting-time distributions for gene switching and transcription initiation, which typically reduce noise in mRNA copy numbers and burst size. Finally, we discuss that qualitatively different gene regulation models can often fit the same experimental data on single-cell mRNA abundance even though they have qualitatively different burst-size statistics and regulatory parameters. PMID:22995487

  18. Mobile Game for Learning Bacteriology

    ERIC Educational Resources Information Center

    Sugimura, Ryo; Kawazu, Sotaro; Tamari, Hiroki; Watanabe, Kodai; Nishimura, Yohei; Oguma, Toshiki; Watanabe, Katsushiro; Kaneko, Kosuke; Okada, Yoshihiro; Yoshida, Motofumi; Takano, Shigeru; Inoue, Hitoshi

    2014-01-01

    This paper treats serious games. Recently, one of the game genres called serious game has become popular, which has other purposes besides enjoyments like education, training and so on. Especially, learning games of the serious games seem very attractive for the age of video games so that the authors developed a mobile game for learning…

  19. Games for Learning

    ERIC Educational Resources Information Center

    Gee, James Paul

    2013-01-01

    Today there is a great deal of interest in and a lot of hype about using video games in schools. Video games are a new silver bullet. Games can create good learning because they teach in powerful ways. The theory behind game-based learning is not really new, but a traditional and well-tested approach to deep and effective learning, often…

  20. Play the Mosquito Game

    MedlinePLUS

    ... and Work Teachers' Questionnaire Malaria Play the Mosquito Game Play the Parasite Game About the games Malaria is one of the world's most common ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  1. Learning with Calculator Games

    ERIC Educational Resources Information Center

    Frahm, Bruce

    2013-01-01

    Educational games provide a fun introduction to new material and a review of mathematical algorithms. Specifically, games can be designed to assist students in developing mathematical skills as an incidental consequence of the game-playing process. The programs presented in this article are adaptations of board games or television shows that…

  2. Games for Learning

    ERIC Educational Resources Information Center

    Gee, James Paul

    2013-01-01

    Today there is a great deal of interest in and a lot of hype about using video games in schools. Video games are a new silver bullet. Games can create good learning because they teach in powerful ways. The theory behind game-based learning is not really new, but a traditional and well-tested approach to deep and effective learning, often

  3. Learning with Calculator Games

    ERIC Educational Resources Information Center

    Frahm, Bruce

    2013-01-01

    Educational games provide a fun introduction to new material and a review of mathematical algorithms. Specifically, games can be designed to assist students in developing mathematical skills as an incidental consequence of the game-playing process. The programs presented in this article are adaptations of board games or television shows that

  4. Game Board Artists.

    ERIC Educational Resources Information Center

    Szekely, George

    2000-01-01

    Explores children's fascination with creating their own unique games as an art form. Focuses on different games, such as chess, checkers, pogs, and monopoly. States that observing children playing games offers a firsthand lesson in how children create. Discusses what it means to be an art teacher who promotes creative play with games. (CMK)

  5. Effects of Input Noise on a Simple Biochemical Switch

    NASA Astrophysics Data System (ADS)

    Hu, Bo; Kessler, David A.; Rappel, Wouter-Jan; Levine, Herbert

    2011-09-01

    Many biological processes are controlled by biomolecular switches which themselves are regulated by various upstream chemical molecules (the input). Understanding how input noise affects the output stochastic switching process is of significant interest in various biophysical systems like gene regulation, chemosensing, and cell motility. Here, we propose an exactly solvable model where the noisy input signal arises from a simple birth-death process and directly regulates the transition rates of a downstream switch. We solve the joint master equations to analyze the statistical properties of the output switching process. Our results suggest that the conventional wisdom of an additive input-output noise rule fails to describe signaling systems containing a single molecular switch, and, instead, the most important effect of input noise is to effectively reduce the on rate of the switch.

  6. Phenotypic switching in bacteria

    NASA Astrophysics Data System (ADS)

    Merrin, Jack

    Living matter is a non-equilibrium system in which many components work in parallel to perpetuate themselves through a fluctuating environment. Physiological states or functionalities revealed by a particular environment are called phenotypes. Transitions between phenotypes may occur either spontaneously or via interaction with the environment. Even in the same environment, genetically identical bacteria can exhibit different phenotypes of a continuous or discrete nature. In this thesis, we pursued three lines of investigation into discrete phenotypic heterogeneity in bacterial populations: the quantitative characterization of the so-called bacterial persistence, a theoretical model of phenotypic switching based on those measurements, and the design of artificial genetic networks which implement this model. Persistence is the phenotype of a subpopulation of bacteria with a reduced sensitivity to antibiotics. We developed a microfluidic apparatus, which allowed us to monitor the growth rates of individual cells while applying repeated cycles of antibiotic treatments. We were able to identify distinct phenotypes (normal and persistent) and characterize the stochastic transitions between them. We also found that phenotypic heterogeneity was present prior to any environmental cue such as antibiotic exposure. Motivated by the experiments with persisters, we formulated a theoretical model describing the dynamic behavior of several discrete phenotypes in a periodically varying environment. This theoretical framework allowed us to quantitatively predict the fitness of dynamic populations and to compare survival strategies according to environmental time-symmetries. These calculations suggested that persistence is a strategy used by bacterial populations to adapt to fluctuating environments. Knowledge of the phenotypic transition rates for persistence may provide statistical information about the typical environments of bacteria. We also describe a design of artificial genetic networks that would implement a more general theoretical model of phenotypic switching. We will use a new cloning strategy in order to systematically assemble a large number of genetic features, such as site-specific recombination components from the R64 plasmid, which invert several coexisting DNA segments. The inversion of these segments would lead to discrete phenotypic transitions inside a living cell. These artificial phenotypic switches can be controlled precisely in experiments and may serve as a benchmark for their natural counterparts.

  7. Magnetic switching

    SciTech Connect

    Birx, D.; Cook, E.; Hawkins, S.; Poor, S.; Reginato, L.; Schmidt, J.; Smith, M.

    1983-06-01

    The paper discusses the development program in magnetic switching which was aimed at solving the rep-rate and reliability limitations of the ATA spark gaps. The end result has been a prototype physically very similar to the present Advanced Test Accelerator (ATA) pulse power unit but vastly superior in performance. This prototype, which is easily adaptable to the existing systems, has achieved a burst rep-rate of 20 kHz and an output voltage of 500 kV. A one-on-one substitution of the existing pulse power module would result in a 100 MeV accelerator. Furthermore, the high efficiency of the magnetic pulse compression stages has allowed CW operation of the prototype at one kilohertz opening up other applications for the pulse power. Performance and design details will be described.

  8. The Uses of Teaching Games in Game Theory Classes and Some Experimental Games.

    ERIC Educational Resources Information Center

    Shubik, Martin

    2002-01-01

    Discusses the use of lightly controlled games, primarily in classes in game theory. Considers the value of such games from the viewpoint of both teaching and experimentation and discusses context; control; pros and cons of games in teaching; experimental games; and games in class, including cooperative game theory. (Author/LRW)

  9. Emergence of phenotype switching through continuous and discontinuous evolutionary transitions

    NASA Astrophysics Data System (ADS)

    Patra, Pintu; Klumpp, Stefan

    2015-07-01

    Bacterial persistence (phenotypic tolerance to antibiotics) provides a prime example of bet-hedging, where normally growing cells generate slow-growing but antibiotic-tolerant persister cells to survive through periods of exposure to antibiotics. The population dynamics of persistence is explained by a phenotype switching mechanism that allows individual cells to switch between these different cellular states with different environmental sensitivities. Here, we perform a theoretical study based on an exact solution for the case of a periodic variation of the environment to address how phenotype switching emerges and under what conditions switching is or is not beneficial for long-time growth. Specifically we report a bifurcation through which a fitness maximum and minimum emerge above a threshold in the duration of exposure to the antibiotic. Only above this threshold, the optimal phenotype switching rates are adjusted to the time scales of the environment, as emphasized by previous theoretical studies, while below the threshold a non-switching population is fitter than a switching one. The bifurcation can be of different type, depending on how the phenotype switching rates are allowed to vary. If the switching rates for both directions of the switch are coupled, the transition is discontinuous and results in evolutionary hysteresis, which we confirm with a stochastic simulation. If the switching rates vary individually, a continuous transition is obtained and no hysteresis is found. We discuss how both scenarios can be linked to changes in the underlying molecular networks.

  10. Quantum Stochastic Processes

    SciTech Connect

    Spring, William Joseph

    2009-04-13

    We consider quantum analogues of n-parameter stochastic processes, associated integrals and martingale properties extending classical results obtained in [1, 2, 3], and quantum results in [4, 5, 6, 7, 8, 9, 10].

  11. Evolutionary Games with Randomly Changing Payoff Matrices

    NASA Astrophysics Data System (ADS)

    Yakushkina, Tatiana; Saakian, David B.; Bratus, Alexander; Hu, Chin-Kun

    2015-06-01

    Evolutionary games are used in various fields stretching from economics to biology. In most of these games a constant payoff matrix is assumed, although some works also consider dynamic payoff matrices. In this article we assume a possibility of switching the system between two regimes with different sets of payoff matrices. Potentially such a model can qualitatively describe the development of bacterial or cancer cells with a mutator gene present. A finite population evolutionary game is studied. The model describes the simplest version of annealed disorder in the payoff matrix and is exactly solvable at the large population limit. We analyze the dynamics of the model, and derive the equations for both the maximum and the variance of the distribution using the Hamilton-Jacobi equation formalism.

  12. On Equilibria for ADM Minimization Games

    NASA Astrophysics Data System (ADS)

    Epstein, Leah; Levin, Asaf

    In the ADM minimization problem, the input is a set of arcs along a directed ring. The input arcs need to be partitioned into non-overlapping chains and cycles so as to minimize the total number of endpoints, where a k-arc cycle contributes k endpoints and a k-arc chain contains k + 1 endpoints. We study ADM minimization problem both as a non-cooperative and a cooperative games. In these games, each arc corresponds to a player, and the players share the cost of the ADM switches. We consider two cost allocation models, a model which was considered by Flammini et al., and a new cost allocation model, which is inspired by congestion games. We compare the price of anarchy and price of stability in the two cost allocation models, as well as the strong price of anarchy and the strong price of stability.

  13. The Cell Cycle Switch Computes Approximate Majority

    NASA Astrophysics Data System (ADS)

    Cardelli, Luca; Csikász-Nagy, Attila

    2012-09-01

    Both computational and biological systems have to make decisions about switching from one state to another. The `Approximate Majority' computational algorithm provides the asymptotically fastest way to reach a common decision by all members of a population between two possible outcomes, where the decision approximately matches the initial relative majority. The network that regulates the mitotic entry of the cell-cycle in eukaryotes also makes a decision before it induces early mitotic processes. Here we show that the switch from inactive to active forms of the mitosis promoting Cyclin Dependent Kinases is driven by a system that is related to both the structure and the dynamics of the Approximate Majority computation. We investigate the behavior of these two switches by deterministic, stochastic and probabilistic methods and show that the steady states and temporal dynamics of the two systems are similar and they are exchangeable as components of oscillatory networks.

  14. The $-game

    NASA Astrophysics Data System (ADS)

    Vitting Andersen, J.; Sornette, D.

    2003-01-01

    We propose a payoff function extending Minority Games (MG) that captures the competition between agents to make money. In contrast with previous MG, the best strategies are not always targeting the minority but are shifting opportunistically between the minority and the majority. The emergent properties of the price dynamics and of the wealth of agents are strikingly different from those found in MG. As the memory of agents is increased, we find a phase transition between a self-sustained speculative phase in which a ``stubborn majority'' of agents effectively collaborate to arbitrage a market-maker for their mutual benefit and a phase where the market-maker always arbitrages the agents. A subset of agents exhibit a sustained non-equilibrium risk-return profile.

  15. Beating Cheaters at Their Own Game

    NASA Astrophysics Data System (ADS)

    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.

  16. Switch Transcripts in Immunoglobulin Class Switching

    NASA Astrophysics Data System (ADS)

    Lorenz, Matthias; Jung, Steffen; Radbruch, Andreas

    1995-03-01

    B cells can exchange gene segments for the constant region of the immunoglobulin heavy chain, altering the class and effector function of the antibodies that they produce. Class switching is directed to distinct classes by cytokines, which induce transcription of the targeted DNA sequences. These transcripts are processed, resulting in spliced "switch" transcripts. Switch recombination can be directed to immunoglobulin G1 (IgG1) by the heterologous human metallothionein II_A promoter in mutant mice. Induction of the structurally conserved, spliced switch transcripts is sufficient to target switch recombination to IgG1, whereas transcription alone is not.

  17. Information Security Analysis Using Game Theory and Simulation

    SciTech Connect

    Schlicher, Bob G; Abercrombie, Robert K

    2012-01-01

    Information security analysis can be performed using game theory implemented in dynamic simulations of Agent Based Models (ABMs). Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. Our approach addresses imperfect information and scalability that allows us to also address previous limitations of current stochastic game models. Such models only consider perfect information assuming that the defender is always able to detect attacks; assuming that the state transition probabilities are fixed before the game assuming that the players actions are always synchronous; and that most models are not scalable with the size and complexity of systems under consideration. Our use of ABMs yields results of selected experiments that demonstrate our proposed approach and provides a quantitative measure for realistic information systems and their related security scenarios.

  18. Latching relay switch assembly

    DOEpatents

    Duimstra, Frederick A.

    1991-01-01

    A latching relay switch assembly which includes a coil section and a switch or contact section. The coil section includes at least one permanent magnet and at least one electromagnet. The respective sections are, generally, arranged in separate locations or cavities in the assembly. The switch is latched by a permanent magnet assembly and selectively switched by an overriding electromagnetic assembly.

  19. Miniature intermittent contact switch

    NASA Technical Reports Server (NTRS)

    Sword, A.

    1972-01-01

    Design of electric switch for providing intermittent contact is presented. Switch consists of flexible conductor surrounding, but separated from, fixed conductor. Flexing of outside conductor to contact fixed conductor completes circuit. Advantage is small size of switch compared to standard switches.

  20. Social Studies Games on Parade.

    ERIC Educational Resources Information Center

    Bolger, Charlene

    Elementary school teachers are provided with materials and instructions for using a variety of social studies games. The 15 games described are: charades, checker states, hollywood squares, states guessing game, index relay, jeopardy, the match game, the money game, password, the states game, sequence, stump the students, track meet, famous person

  1. Simulation Games in Moral Education

    ERIC Educational Resources Information Center

    Boulogne, Jack

    1978-01-01

    Discusses the value of simulation games in moral education in four categories: fun and games; games as simulations of real life; games as motivators; and morality and game theory. Also examines the gaming aspects of morality, as well as the physical, psychological, precedent-setting, and internal consequences of an action. (Author/JK)

  2. The Easiest Lights Out Games

    ERIC Educational Resources Information Center

    Torrence, Bruce

    2011-01-01

    The game "Lights Out" and its mathematical predecessor, the sigma-plus game, has inspired an extensive mathematical literature. In this paper, the original game and a borderless version played on a torus are considered. We define an easy game to be one in which pushing the buttons that are originally lit solves the game. Easy games are classified…

  3. Social Studies Games on Parade.

    ERIC Educational Resources Information Center

    Bolger, Charlene

    Elementary school teachers are provided with materials and instructions for using a variety of social studies games. The 15 games described are: charades, checker states, hollywood squares, states guessing game, index relay, jeopardy, the match game, the money game, password, the states game, sequence, stump the students, track meet, famous person…

  4. The Easiest Lights Out Games

    ERIC Educational Resources Information Center

    Torrence, Bruce

    2011-01-01

    The game "Lights Out" and its mathematical predecessor, the sigma-plus game, has inspired an extensive mathematical literature. In this paper, the original game and a borderless version played on a torus are considered. We define an easy game to be one in which pushing the buttons that are originally lit solves the game. Easy games are classified

  5. Real-Time Strategy Game Training: Emergence of a Cognitive Flexibility Trait

    PubMed Central

    Glass, Brian D.; Maddox, W. Todd; Love, Bradley C.

    2013-01-01

    Training in action video games can increase the speed of perceptual processing. However, it is unknown whether video-game training can lead to broad-based changes in higher-level competencies such as cognitive flexibility, a core and neurally distributed component of cognition. To determine whether video gaming can enhance cognitive flexibility and, if so, why these changes occur, the current study compares two versions of a real-time strategy (RTS) game. Using a meta-analytic Bayes factor approach, we found that the gaming condition that emphasized maintenance and rapid switching between multiple information and action sources led to a large increase in cognitive flexibility as measured by a wide array of non-video gaming tasks. Theoretically, the results suggest that the distributed brain networks supporting cognitive flexibility can be tuned by engrossing video game experience that stresses maintenance and rapid manipulation of multiple information sources. Practically, these results suggest avenues for increasing cognitive function. PMID:23950921

  6. Interplay between stochasticity and negative feedback leads to pulsed dynamics and distinct gene activity patterns

    NASA Astrophysics Data System (ADS)

    Zambrano, Samuel; Bianchi, Marco E.; Agresti, Alessandra; Molina, Nacho

    2015-08-01

    Gene expression is an inherently stochastic process that depends on the structure of the biochemical regulatory network in which the gene is embedded. Here we study the dynamical consequences of the interplay between stochastic gene switching and the widespread negative feedback regulatory loop in a simple model of a biochemical regulatory network. Using a simplified hybrid simulation approach, in which only the gene activation is modeled stochastically, we find that stochasticity in gene switching by itself can induce pulses in the system, providing also analytical insights into their origin. Furthermore, we find that this simple network is able to reproduce both exponential and peaked distributions of gene active and inactive times similar to those that have been observed experimentally. This simplified hybrid simulation approach also allows us to link these patterns to the dynamics of the system for each gene state.

  7. Interplay between stochasticity and negative feedback leads to pulsed dynamics and distinct gene activity patterns.

    PubMed

    Zambrano, Samuel; Bianchi, Marco E; Agresti, Alessandra; Molina, Nacho

    2015-08-01

    Gene expression is an inherently stochastic process that depends on the structure of the biochemical regulatory network in which the gene is embedded. Here we study the dynamical consequences of the interplay between stochastic gene switching and the widespread negative feedback regulatory loop in a simple model of a biochemical regulatory network. Using a simplified hybrid simulation approach, in which only the gene activation is modeled stochastically, we find that stochasticity in gene switching by itself can induce pulses in the system, providing also analytical insights into their origin. Furthermore, we find that this simple network is able to reproduce both exponential and peaked distributions of gene active and inactive times similar to those that have been observed experimentally. This simplified hybrid simulation approach also allows us to link these patterns to the dynamics of the system for each gene state. PMID:26382436

  8. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E. (Albuquerque, NM)

    1990-01-01

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  9. Promotion of cooperation by payoff noise in a 2×2 game

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun

    2007-10-01

    A series of numerical simulations of a 2×2 symmetric game on a network examined whether payoff matrix noise promotes cooperation, as reported initially by Perc [New J. Phys. 8, 22 (2006)]. Agents have no memory (they offer cooperation, C , or defection, D ). We assume that the network is time invariable. The effect of payoff matrix noise (PMN) is measured by a simulated payoff difference between a normal network game and a network game with PMN. The effect of PMN appears only when a local strategy adaptation is implemented (for example, a network game with imitation dynamics). The influence of PMN becomes more significant with a larger stochastic deviation, and less significant in a larger degree network. One reason for PMN’s effectiveness is the local strategy adaptation mechanism, which helps both the preservation and fixation of C agents, and not that the payoff matrix noise makes a dilemma game into a Trivial (dilemma-free) game.

  10. Stochastic gene expression as a many-body problem

    PubMed Central

    Sasai, Masaki; Wolynes, Peter G.

    2003-01-01

    Gene expression has a stochastic component because of the single-molecule nature of the gene and the small number of copies of individual DNA-binding proteins in the cell. We show how the statistics of such systems can be mapped onto quantum many-body problems. The dynamics of a single gene switch resembles the spin-boson model of a two-site polaron or an electron transfer reaction. Networks of switches can be approximately described as quantum spin systems by using an appropriate variational principle. In this way, the concept of frustration for magnetic systems can be taken over into gene networks. The landscape of stable attractors depends on the degree and style of frustration, much as for neural networks. We show the number of attractors, which may represent cell types, is much smaller for appropriately designed weakly frustrated stochastic networks than for randomly connected networks. PMID:12606710

  11. Pathogen evolution in switching environments: a hybrid dynamical system approach.

    PubMed

    Farkas, Jzsef Z; Hinow, Peter; Engelstdter, Jan

    2012-11-01

    We propose a hybrid dynamical system approach to model the evolution of a pathogen that experiences different selective pressures according to a stochastic process. In every environment, the evolution of the pathogen is described by a version of the Fisher-Haldane-Wright equation while the switching between environments follows a Markov jump process. We investigate how the qualitative behavior of a simple single-host deterministic system changes when the stochastic switching process is added. In particular, we study the stability in probability of monomorphic equilibria. We prove that in a "constantly" fluctuating environment, the genotype with the highest mean fitness is asymptotically stable in probability while all others are unstable in probability. However, if the probability of host switching depends on the genotype composition of the population, polymorphism can be stably maintained. PMID:22749893

  12. Stochastic Matching Problem

    NASA Astrophysics Data System (ADS)

    Altarelli, F.; Braunstein, A.; Ramezanpour, A.; Zecchina, R.

    2011-05-01

    The matching problem plays a basic role in combinatorial optimization and in statistical mechanics. In its stochastic variants, optimization decisions have to be taken given only some probabilistic information about the instance. While the deterministic case can be solved in polynomial time, stochastic variants are worst-case intractable. We propose an efficient method to solve stochastic matching problems which combines some features of the survey propagation equations and of the cavity method. We test it on random bipartite graphs, for which we analyze the phase diagram and compare the results with exact bounds. Our approach is shown numerically to be effective on the full range of parameters, and to outperform state-of-the-art methods. Finally we discuss how the method can be generalized to other problems of optimization under uncertainty.

  13. Stochastic modelling of intermittency.

    PubMed

    Stemler, Thomas; Werner, Johannes P; Benner, Hartmut; Just, Wolfram

    2010-01-13

    Recently, methods have been developed to model low-dimensional chaotic systems in terms of stochastic differential equations. We tested such methods in an electronic circuit experiment. We aimed to obtain reliable drift and diffusion coefficients even without a pronounced time-scale separation of the chaotic dynamics. By comparing the analytical solutions of the corresponding Fokker-Planck equation with experimental data, we show here that crisis-induced intermittency can be described in terms of a stochastic model which is dominated by state-space-dependent diffusion. Further on, we demonstrate and discuss some limits of these modelling approaches using numerical simulations. This enables us to state a criterion that can be used to decide whether a stochastic model will capture the essential features of a given time series. PMID:19948556

  14. Quantum signaling game

    NASA Astrophysics Data System (ADS)

    Frackiewicz, Piotr

    2014-08-01

    We present a quantum approach to a signaling game; a special kind of extensive game of incomplete information. Our model is based on quantum schemes for games in strategic form where players perform unitary operators on their own qubits of some fixed initial state and the payoff function is given by a measurement on the resulting final state. We show that the quantum game induced by our scheme coincides with a signaling game as a special case and outputs nonclassical results in general. As an example, we consider a quantum extension of the signaling game in which the chance move is a three-parameter unitary operator whereas the players' actions are equivalent to classical ones. In this case, we study the game in terms of Nash equilibria and refine the pure Nash equilibria adapting to the quantum game the notion of a weak perfect Bayesian equilibrium.

  15. Mang Kung Dice Game.

    ERIC Educational Resources Information Center

    Chan, Wai-Sum

    1996-01-01

    Describes the Mang Kung Dice Game, popular in China, which uses six special dice. Discusses the probability distribution of possible outcomes. Poses questions about the game to help students understand statistical concepts. (MKR)

  16. Interactive Health Games

    MedlinePLUS

    ... Safety Education) Food Safety Mobile Game (Department of Agriculture, Food Safety and Inspection Service) Michael's Inside Scoop: ... Safety Education) Food Safety Mobile Game (Department of Agriculture, Food Safety and Inspection Service) Foodborne Illness Food ...

  17. Stinging Insect Matching Game

    MedlinePLUS

    ... for Kids ? Stinging Insect Matching Game Share | Stinging Insect Matching Game Stinging insects can ruin summer fun for those who are ... the difference between the different kinds of stinging insects in order to keep your summer safe and ...

  18. Wolf Trek Game.

    ERIC Educational Resources Information Center

    DeRosa, Bill

    1988-01-01

    Describes a learning center game which is designed to help elementary school students learn about wolves. Includes playing instructions, game board, and questions and answers. Also included is a record of wolf calls narrated by actor Robert Redford. (TW)

  19. Intrinsic noise in game dynamical learning.

    PubMed

    Galla, Tobias

    2009-11-01

    Demographic noise has profound effects on evolutionary and population dynamics, as well as on chemical reaction systems and models of epidemiology. Such noise is intrinsic and due to the discreteness of the dynamics in finite populations. We here show that similar noise-sustained trajectories arise in game dynamical learning, where the stochasticity has a different origin: agents sample a finite number of moves of their opponents in between adaptation events. The limit of infinite batches results in deterministic modified replicator equations, whereas finite sampling leads to a stochastic dynamics. The characteristics of these fluctuations can be computed analytically using methods from statistical physics, and such noise can affect the attractors significantly, leading to noise-sustained cycling or removing periodic orbits of the standard replicator dynamics. PMID:20365961

  20. Dynamic Robust Games in MIMO Systems.

    PubMed

    Tembine, H

    2011-08-01

    In this paper, we study dynamic robust power-allocation games in multiple-input-multiple-output systems under the imperfectness of the channel-state information at the transmitters. Using a robust pseudopotential-game approach, we show the existence of robust solutions in both discrete and continuous action spaces under suitable conditions. Considering the imperfectness in terms of the payoff measurement at the transmitters, we propose a COmbined fully DIstributed Payoff and Strategy Reinforcement Learning (CODIPAS-RL) in which each transmitter learns its payoff function, as well as the associated optimal covariance matrix strategies. Under the heterogeneous CODIPAS-RL, the transmitters can use different learning patterns (heterogeneous learning) and different learning rates. We provide sufficient conditions for the almost-sure convergence of the heterogeneous learning to ordinary differential equations. Extensions of the CODIPAS-RL to It's stochastic differential equations are discussed. PMID:21266314

  1. Stochastic Gauss equations

    NASA Astrophysics Data System (ADS)

    Pierret, Frdric

    2016-02-01

    We derived the equations of Celestial Mechanics governing the variation of the orbital elements under a stochastic perturbation, thereby generalizing the classical Gauss equations. Explicit formulas are given for the semimajor axis, the eccentricity, the inclination, the longitude of the ascending node, the pericenter angle, and the mean anomaly, which are expressed in term of the angular momentum vector H per unit of mass and the energy E per unit of mass. Together, these formulas are called the stochastic Gauss equations, and they are illustrated numerically on an example from satellite dynamics.

  2. Stochastic Gauss equations

    NASA Astrophysics Data System (ADS)

    Pierret, Frdric

    2015-10-01

    We derived the equations of Celestial Mechanics governing the variation of the orbital elements under a stochastic perturbation, thereby generalizing the classical Gauss equations. Explicit formulas are given for the semimajor axis, the eccentricity, the inclination, the longitude of the ascending node, the pericenter angle, and the mean anomaly, which are expressed in term of the angular momentum vector H per unit of mass and the energy E per unit of mass. Together, these formulas are called the stochastic Gauss equations, and they are illustrated numerically on an example from satellite dynamics.

  3. Multi-scenario modelling of uncertainty in stochastic chemical systems

    NASA Astrophysics Data System (ADS)

    Evans, R. David; Ricardez-Sandoval, Luis A.

    2014-09-01

    Uncertainty analysis has not been well studied at the molecular scale, despite extensive knowledge of uncertainty in macroscale systems. The ability to predict the effect of uncertainty allows for robust control of small scale systems such as nanoreactors, surface reactions, and gene toggle switches. However, it is difficult to model uncertainty in such chemical systems as they are stochastic in nature, and require a large computational cost. To address this issue, a new model of uncertainty propagation in stochastic chemical systems, based on the Chemical Master Equation, is proposed in the present study. The uncertain solution is approximated by a composite state comprised of the averaged effect of samples from the uncertain parameter distributions. This model is then used to study the effect of uncertainty on an isomerization system and a two gene regulation network called a repressilator. The results of this model show that uncertainty in stochastic systems is dependent on both the uncertain distribution, and the system under investigation.

  4. Distribution of population-averaged observables in stochastic gene expression

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Bhaswati; Kalay, Ziya

    2014-01-01

    Observation of phenotypic diversity in a population of genetically identical cells is often linked to the stochastic nature of chemical reactions involved in gene regulatory networks. We investigate the distribution of population-averaged gene expression levels as a function of population, or sample, size for several stochastic gene expression models to find out to what extent population-averaged quantities reflect the underlying mechanism of gene expression. We consider three basic gene regulation networks corresponding to transcription with and without gene state switching and translation. Using analytical expressions for the probability generating function of observables and large deviation theory, we calculate the distribution and first two moments of the population-averaged mRNA and protein levels as a function of model parameters, population size, and number of measurements contained in a data set. We validate our results using stochastic simulations also report exact results on the asymptotic properties of population averages which show qualitative differences among different models.

  5. Stochastic entrainment of a stochastic oscillator

    NASA Astrophysics Data System (ADS)

    Wang, Guanyu; Peskin, Charles S.

    2015-11-01

    In this work, we consider a stochastic oscillator described by a discrete-state continuous-time Markov chain, in which the states are arranged in a circle, and there is a constant probability per unit time of jumping from one state to the next in a specified direction around the circle. At each of a sequence of equally spaced times, the oscillator has a specified probability of being reset to a particular state. The focus of this work is the entrainment of the oscillator by this periodic but stochastic stimulus. We consider a distinguished limit, in which (i) the number of states of the oscillator approaches infinity, as does the probability per unit time of jumping from one state to the next, so that the natural mean period of the oscillator remains constant, (ii) the resetting probability approaches zero, and (iii) the period of the resetting signal approaches a multiple, by a ratio of small integers, of the natural mean period of the oscillator. In this distinguished limit, we use analytic and numerical methods to study the extent to which entrainment occurs.

  6. STOCHASTIC COOLING FOR BUNCHED BEAMS.

    SciTech Connect

    BLASKIEWICZ, M.

    2005-05-16

    Problems associated with bunched beam stochastic cooling are reviewed. A longitudinal stochastic cooling system for RHIC is under construction and has been partially commissioned. The state of the system and future plans are discussed.

  7. Dynamics of multi-frequency minority games

    NASA Astrophysics Data System (ADS)

    de Martino, A.

    2003-09-01

    The dynamics of minority games with agents trading on different time scales is studied via dynamical mean-field theory. We analyze the case where the agents’ decision-making process is deterministic and its stochastic generalization with finite heterogeneous learning rates. In each case, we characterize the macroscopic properties of the steady states resulting from different frequency and learning rate distributions and calculate the corresponding phase diagrams. Finally, the different roles played by regular and occasional traders, as well as their impact on the system’s global efficiency, are discussed.

  8. Being a Game Changer

    ERIC Educational Resources Information Center

    Herrig, Brian; Taranto, Greg

    2012-01-01

    One of the key features that draws many people to play video games is the fact that they are interactive. Video games allow the user to be actively engaged and in control of the action (Prensky, 2006). Seventh grade students at Canonsburg Middle School are actively engaging in the creation of video games. The students are engaged at a much deeper

  9. Getting into the Game

    ERIC Educational Resources Information Center

    Jenkins, Henry

    2005-01-01

    Statistics reveal that students spend more time on electronic games than on any other recreational activity and 32% admit to playing them during class. The gaming revolution contains lessons for teachers, and understanding the pedagogical potential of computer and video games and developing curriculum that supports the educational use of

  10. The Acid Rain Game.

    ERIC Educational Resources Information Center

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  11. Time for Bed Game

    MedlinePLUS

    ... a Friend Who Cuts? Babysitting: Time for Bed Game KidsHealth > For Teens > Babysitting: Time for Bed Game Print A A A Text Size What Kids ... kids to bed can be tough sometimes! This game introduces children to the concept of getting enough ...

  12. First Video Game

    SciTech Connect

    Peter Takacs

    2008-10-21

    Fifty years ago, before either arcades or home video games, visitors waited in line at Brookhaven National Laboratory to play Tennis for Two, an electronic tennis game that is unquestionably a forerunner of the modern video game. Two people played the ele

  13. Friend Finder (Game)

    MedlinePLUS

    ... página en español Video and Media Friend Finder (Game) Email Embed Grab this Game : Stay Teen: Games

    MedlinePLUS

    ... by You are here Home » Games and Quizzes Games and Quizzes Facebook Twitter Tumblr Shares · 47 quiz ... Year’s Relationship Resolution Be? Shares · 4 Comments · 0 game Block Party Shares · 30 Comments · 0 quiz Should ...

  14. Simulation Games in Learning.

    ERIC Educational Resources Information Center

    Boocock, Sarane S., Ed.; Schild, E.O., Ed.

    Simulation games serve many functions, but the important one to educators is that they present the student player with a real-life situation allowing him to use his knowledge and abilities while discovering decision-making skills for himself. To provide a basic reference on simulation gaming, essays on various aspects of games were collected from

  15. Gaming Gains Respect

    ERIC Educational Resources Information Center

    Richardson, Will

    2012-01-01

    The idea of learning through games isn't necessarily new. In fact, over the past decade, researchers have been espousing the use of games to help both children and adults learn. But it's only been recently that games have begun to make serious inroads into classrooms. As the world becomes more and more driven by mobile apps and tablet

  16. Inventing Music Education Games

    ERIC Educational Resources Information Center

    Ghere, David; Amram, Fred M. B.

    2007-01-01

    The first British patent describing an educational game designed for musical "amusement and instruction" was granted in 1801 to Ann Young of Edinburgh, Scotland. The authors' discovery of Young's game box has prompted an examination of the nature and purpose of the six games she designed. Ann Young's patent is discussed in the context of…

  17. Playing the Cell Game.

    ERIC Educational Resources Information Center

    Madrazo, Gerry M., Jr.; Wood, Carol A.

    1980-01-01

    Discusses the use of games to facilitate learning scientific concepts and principles. Describes the Cell Game, which simulates plant and animal cells; the Energy Quest, which requires players to buy property that generates largest amounts of electricity; the Blood Flow Game, which illustrates circulation of blood through the human body. (CS)

  18. Inventing Music Education Games

    ERIC Educational Resources Information Center

    Ghere, David; Amram, Fred M. B.

    2007-01-01

    The first British patent describing an educational game designed for musical "amusement and instruction" was granted in 1801 to Ann Young of Edinburgh, Scotland. The authors' discovery of Young's game box has prompted an examination of the nature and purpose of the six games she designed. Ann Young's patent is discussed in the context of

  19. [Dangerous games in schoolchildren].

    PubMed

    Le Heuzey, M-F

    2011-02-01

    Dangerous games inside or outside school are a serious social phenomenon, but unfortunately underrecognized. Aggressive games are a part of school bullying, which is in expansion. Choking games are very dangerous, with many deaths or serious neurologic complications. Pediatricians should be knowledgeable about risky behaviors encountered by their patients, and provide guidance about its dangers. PMID:21146376

    1. Brain Games for Babies.

      ERIC Educational Resources Information Center

      Silberg, Jackie

      2001-01-01

      Presents games for caregivers to use with infants to enhance brain development. Includes games that develop trust and security, language skills, and fine motor skills, as well as games that are fun or stimulate vision. Includes videotape references for parents and caregivers. (KB)

    2. Kids and Games.

      ERIC Educational Resources Information Center

      McKnight, Regis Q.; McBride, Susan

      1980-01-01

      States that more use should be made of simulation games in elementary school social studies classrooms because pupils enjoy games and can learn a lot from playing them. Describes a simulation game which is modeled on the function of a zoning board. Objectives and evaluation are discussed. (DB)

    3. The Ultimate Flag Games.

      ERIC Educational Resources Information Center

      Angel, Kenny; Sutton, Nancy

      This paper describes six Ultimate Flag Games which offer a change from traditional games and sports that are usually geared toward athletically inclined students. These new games, aimed at middle school through college students, allow for success from the least-skilled through the most athletically talented students. Players are ability grouped…

    4. Educational Games for Learning

      ERIC Educational Resources Information Center

      Noemí, Peña-Miguel; Máximo, Sedano Hoyuelos

      2014-01-01

      The introduction of new technologies in society has created a need for interactive contents that can make the most of the potential that technological advances offer. Serious games as educational games are such content: they can be defined as video games or interactive applications whose main purpose is to provide not only entertainment but also…

    5. International Cooperative Games.

      ERIC Educational Resources Information Center

      Hoppe, Christine

      The book "Of Play and Playfulness" (Eastern Cooperative Recreation School, 1990) is recommended as a source of ideas for second language learning games. It describes folk dances, ideas for crafts, puppetry, games, and a variety of other activities from many countries. Several games from the book, easy to teach in a foreign language or

    6. Indian & Metis Trivia Game.

      ERIC Educational Resources Information Center

      Manitoba Dept. of Education and Training, Winnipeg.

      This booklet consists of 220 questions about Native North Americans and Metis people that can be used as learning activities for elementary and secondary school students. Suggestions for using the questions include playing games in pairs or teams, locating resources to find answers to questions, playing trivia games and board games, and using

    7. The Acid Rain Game.

      ERIC Educational Resources Information Center

      Rakow, Steven J.; Glenn, Allen

      1982-01-01

      Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.

    8. National Gaming Council.

      ERIC Educational Resources Information Center

      House, Peter W.; And Others

      This publication describes thirty-three simulation games discussed at the 9th Symposium of the Council in April of 1970. Those articles related to the social sciences are: 1) Teaching Economics with Competitive Games; 2) An Economic Strategy Analysis Game; 3) A Social Simulation Strategy for Researching the Israeli Arab Conflict; 4) The Use of…

    9. Online Strategy Games.

      ERIC Educational Resources Information Center

      Dye, Bryan

      2002-01-01

      A strategy game is an online interactive game that requires thinking in order to be played at its best and whose winning strategy is not obvious. Provides information on strategy games that are written in Java or JavaScript and freely available on the web. (KHR)

    10. Resource Allocation Games: A Priming Game for a Series of Instructional Games (The POE Game).

      ERIC Educational Resources Information Center

      Allen, Layman E.

      This paper describes in detail the paper-and-pencil POE (Pelham Odd 'R Even) game, in which units of space are the allocated resources. The game is designed to provide an introduction to the rule structure common to the games of EQUATIONS, WFF 'N PROOF, and ON-SENTS & NON-SENTS. Techniques of playing POE, including goals, solutions, moves, scoring

    11. Scientific Fun and Games.

      ERIC Educational Resources Information Center

      Sewall, Susan B.

      1986-01-01

      Presents criteria for having students make their own games which are used by the class to review material covered in life science. Students are required to use recycled materials in producing the game and its accessories. Samples of some of the games produced are included. (TW)

    12. Fun with Games

      NASA Astrophysics Data System (ADS)

      Spirakis, Paul G.; Chatzigiannakis, Ioannis; Mylonas, Georgios; Panagopoulou, Panagiota N.

      We discuss two different ways of having fun with two different kinds of games: On the one hand, we present a framework for developing multiplayer pervasive games that rely on the use of mobile sensor networks. On the other hand, we show how to exploit game theoretic concepts in order to study the graph-theoretic problem of vertex coloring.

    13. First Video Game

      ScienceCinema

      Peter Takacs

      2010-01-08

      Fifty years ago, before either arcades or home video games, visitors waited in line at Brookhaven National Laboratory to play Tennis for Two, an electronic tennis game that is unquestionably a forerunner of the modern video game. Two people played the ele

    14. Temporal switching jitter in photoconductive switches

      SciTech Connect

      GAUDET,JOHN A.; SKIPPER,MICHAEL C.; ABDALLA,MICHAEL D.; AHERN,SEAN M.; MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; O'MALLEY,MARTIN W.; HELGESON,WESLEY D.; ROMERO,SAMUEL P.

      2000-04-13

      This paper reports on a recent comparison made between the Air Force Research Laboratory (AFRL) gallium arsenide, optically-triggered switch test configuration and the Sandia National Laboratories (SNL) gallium arsenide, optically-triggered switch test configuration. The purpose of these measurements was to compare the temporal switch jitter times. It is found that the optical trigger laser characteristics are dominant in determining the PCSS jitter.

    15. Switching between phenotypes and population extinction

      NASA Astrophysics Data System (ADS)

      Lohmar, Ingo; Meerson, Baruch

      2011-11-01

      Many types of bacteria can survive under stress by switching stochastically between two different phenotypes: the “normals” who multiply fast, but are vulnerable to stress, and the “persisters” who hardly multiply, but are resilient to stress. Previous theoretical studies of such bacterial populations have focused on the fitness: the asymptotic rate of unbounded growth of the population. Yet for an isolated population of established (and not very large) size, a more relevant measure may be the population extinction risk due to the interplay of adverse extrinsic variations and intrinsic noise of birth, death and switching processes. Applying a WKB approximation to the pertinent master equation of such a two-population system, we quantify the extinction risk, and find the most likely path to extinction under both favorable and adverse conditions. Analytical results are obtained both in the biologically relevant regime when the switching is rare compared with the birth and death processes, and in the opposite regime of frequent switching. We show that rare switches are most beneficial in reducing the extinction risk.

    16. Stochastic Models of Human Growth.

      ERIC Educational Resources Information Center

      Goodrich, Robert L.

      Stochastic difference equations of the Box-Jenkins form provide an adequate family of models on which to base the stochastic theory of human growth processes, but conventional time series identification methods do not apply to available data sets. A method to identify structure and parameters of stochastic difference equation models of human

    17. Elementary stochastic cooling

      SciTech Connect

      Tollestrup, A.V.; Dugan, G

      1983-12-01

      Major headings in this review include: proton sources; antiproton production; antiproton sources and Liouville, the role of the Debuncher; transverse stochastic cooling, time domain; the accumulator; frequency domain; pickups and kickers; Fokker-Planck equation; calculation of constants in the Fokker-Planck equation; and beam feedback. (GHT)

    18. Latching micro optical switch

      SciTech Connect

      Garcia, Ernest J; Polosky, Marc A

      2013-05-21

      An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

    19. Stochastic computing with biomolecular automata.

      PubMed

      Adar, Rivka; Benenson, Yaakov; Linshiz, Gregory; Rosner, Amit; Tishby, Naftali; Shapiro, Ehud

      2004-07-01

      Stochastic computing has a broad range of applications, yet electronic computers realize its basic step, stochastic choice between alternative computation paths, in a cumbersome way. Biomolecular computers use a different computational paradigm and hence afford novel designs. We constructed a stochastic molecular automaton in which stochastic choice is realized by means of competition between alternative biochemical pathways, and choice probabilities are programmed by the relative molar concentrations of the software molecules coding for the alternatives. Programmable and autonomous stochastic molecular automata have been shown to perform direct analysis of disease-related molecular indicators in vitro and may have the potential to provide in situ medical diagnosis and cure. PMID:15215499

    20. Extended Parrondo's game and Brownian ratchets: Strong and weak Parrondo effect

      NASA Astrophysics Data System (ADS)

      Wu, Degang; Szeto, Kwok Yip

      2014-02-01

      Inspired by the flashing ratchet, Parrondo's game presents an apparently paradoxical situation. Parrondo's game consists of two individual games, game A and game B. Game A is a slightly losing coin-tossing game. Game B has two coins, with an integer parameter M. If the current cumulative capital (in discrete unit) is a multiple of M, an unfavorable coin pb is used, otherwise a favorable pg coin is used. Paradoxically, a combination of game A and game B could lead to a winning game, which is the Parrondo effect. We extend the original Parrondo's game to include the possibility of M being either M1 or M2. Also, we distinguish between strong Parrondo effect, i.e., two losing games combine to form a winning game, and weak Parrondo effect, i.e., two games combine to form a better-performing game. We find that when M2 is not a multiple of M1, the combination of B (M1) and B (M2) has strong and weak Parrondo effect for some subsets in the parameter space (pb,pg), while there is neither strong nor weak effect when M2 is a multiple of M1. Furthermore, when M2 is not a multiple of M1, a stochastic mixture of game A may cancel the strong and weak Parrondo effect. Following a discretization scheme in the literature of Parrondo's game, we establish a link between our extended Parrondo's game with the analysis of discrete Brownian ratchet. We find a relation between the Parrondo effect of our extended model to the macroscopic bias in a discrete ratchet. The slope of a ratchet potential can be mapped to the fair game condition in the extended model, so that under some conditions, the macroscopic bias in a discrete ratchet can provide a good predictor for the game performance of the extended model. On the other hand, our extended model suggests a design of a ratchet in which the potential is a mixture of two periodic potentials.

    1. Extended Parrondo's game and Brownian ratchets: strong and weak Parrondo effect.

      PubMed

      Wu, Degang; Szeto, Kwok Yip

      2014-02-01

      Inspired by the flashing ratchet, Parrondo's game presents an apparently paradoxical situation. Parrondo's game consists of two individual games, game A and game B. Game A is a slightly losing coin-tossing game. Game B has two coins, with an integer parameter M. If the current cumulative capital (in discrete unit) is a multiple of M, an unfavorable coin p(b) is used, otherwise a favorable p(g) coin is used. Paradoxically, a combination of game A and game B could lead to a winning game, which is the Parrondo effect. We extend the original Parrondo's game to include the possibility of M being either M(1) or M(2). Also, we distinguish between strong Parrondo effect, i.e., two losing games combine to form a winning game, and weak Parrondo effect, i.e., two games combine to form a better-performing game. We find that when M(2) is not a multiple of M(1), the combination of B(M(1)) and B(M(2)) has strong and weak Parrondo effect for some subsets in the parameter space (p(b),p(g)), while there is neither strong nor weak effect when M(2) is a multiple of M(1). Furthermore, when M(2) is not a multiple of M(1), a stochastic mixture of game A may cancel the strong and weak Parrondo effect. Following a discretization scheme in the literature of Parrondo's game, we establish a link between our extended Parrondo's game with the analysis of discrete Brownian ratchet. We find a relation between the Parrondo effect of our extended model to the macroscopic bias in a discrete ratchet. The slope of a ratchet potential can be mapped to the fair game condition in the extended model, so that under some conditions, the macroscopic bias in a discrete ratchet can provide a good predictor for the game performance of the extended model. On the other hand, our extended model suggests a design of a ratchet in which the potential is a mixture of two periodic potentials. PMID:25353457

    2. Games and Game Settings for the Preschool Child.

      ERIC Educational Resources Information Center

      Liedtke, Werner; Stott, Gwen

      1979-01-01

      Describes and illustrates games and game settings used in two observational projects dealing with game play by young children. One project presented games encouraging use of strategies; the other provided game equipment and invited the children to invent their own rules and playing procedures. (DS)

    3. Heat Switches for ADRs

      NASA Technical Reports Server (NTRS)

      DiPirro, M. J.; Shirron, P. J.

      2014-01-01

      Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.

    4. Automatic thermal switches

      NASA Technical Reports Server (NTRS)

      Cunningham, J. W.; Wing, L. D.

      1980-01-01

      Two automatic switches control heat flow from one thermally conductive plate to another. One switch permits heat flow to outside; other limits heat flow. In one switch, heat on conductive plate activates piston that forces saddle against plate. Heat carriers then conduct heat to second plate that radiates it away. After temperature is first plate drops, piston contracts and spring breaks thermal contact with plate. In second switch, action is reversed.

    5. Remote switch actuator

      DOEpatents

      Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan

      2013-01-29

      The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

    6. Heat switches for ADRs

      NASA Astrophysics Data System (ADS)

      DiPirro, M. J.; Shirron, P. J.

      2014-07-01

      Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.

    7. Coherent signal amplification in bistable nanomechanical oscillators by stochastic resonance

      NASA Astrophysics Data System (ADS)

      Badzey, Robert L.; Mohanty, Pritiraj

      2005-10-01

      Stochastic resonance is a counterintuitive concept: the addition of noise to a noisy system induces coherent amplification of its response. First suggested as a mechanism for the cyclic recurrence of ice ages, stochastic resonance has been seen in a wide variety of macroscopic physical systems: bistable ring lasers, superconducting quantum interference devices (SQUIDs), magnetoelastic ribbons and neurophysiological systems such as the receptors in crickets and crayfish. Although fundamentally important as a mechanism of coherent signal amplification, stochastic resonance has yet to be observed in nanoscale systems. Here we report the observation of stochastic resonance in bistable nanomechanical silicon oscillators. Our nanomechanical systems consist of beams that are clamped at each end and driven into transverse oscillation with the use of a radiofrequency source. Modulation of the source induces controllable switching of the beams between two stable, distinct states. We observe that the addition of white noise causes a marked amplification of the signal strength. Stochastic resonance in nanomechanical systems could have a function in the realization of controllable high-speed nanomechanical memory cells, and paves the way for exploring macroscopic quantum coherence and tunnelling.

    8. Sex, Lies and Video Games

      ERIC Educational Resources Information Center

      Kearney, Paul; Pivec, Maja

      2007-01-01

      Sex and violence in video games is a social issue that confronts us all, especially as many commercial games are now being introduced for game-based learning in schools, and as such this paper polls teenage players about the rules their parents and teachers may or may not have, and surveys the gaming community, ie, game developers to parents, to…

    9. Sex, Lies and Video Games

      ERIC Educational Resources Information Center

      Kearney, Paul; Pivec, Maja

      2007-01-01

      Sex and violence in video games is a social issue that confronts us all, especially as many commercial games are now being introduced for game-based learning in schools, and as such this paper polls teenage players about the rules their parents and teachers may or may not have, and surveys the gaming community, ie, game developers to parents, to

    10. Triggered plasma opening switch

      DOEpatents

      Mendel, Clifford W. (Albuquerque, NM)

      1988-01-01

      A triggerable opening switch for a very high voltage and current pulse includes a transmission line extending from a source to a load and having an intermediate switch section including a plasma for conducting electrons between transmission line conductors and a magnetic field for breaking the plasma conduction path and magnetically insulating the electrons when it is desired to open the switch.

    11. Apollo Ring Optical Switch

      SciTech Connect

      Maestas, J.H.

      1987-03-01

      An optical switch was designed, built, and installed at Sandia National Laboratories in Albuquerque, New Mexico, to facilitate the integration of two Apollo computer networks into a single network. This report presents an overview of the optical switch as well as its layout, switch testing procedure and test data, and installation.

    12. Stochastic Dynamics Underlying Cognitive Stability and Flexibility

      PubMed Central

      Ueltzhöffer, Kai; Armbruster-Genç, Diana J. N.; Fiebach, Christian J.

      2015-01-01

      Cognitive stability and flexibility are core functions in the successful pursuit of behavioral goals. While there is evidence for a common frontoparietal network underlying both functions and for a key role of dopamine in the modulation of flexible versus stable behavior, the exact neurocomputational mechanisms underlying those executive functions and their adaptation to environmental demands are still unclear. In this work we study the neurocomputational mechanisms underlying cue based task switching (flexibility) and distractor inhibition (stability) in a paradigm specifically designed to probe both functions. We develop a physiologically plausible, explicit model of neural networks that maintain the currently active task rule in working memory and implement the decision process. We simplify the four-choice decision network to a nonlinear drift-diffusion process that we canonically derive from a generic winner-take-all network model. By fitting our model to the behavioral data of individual subjects, we can reproduce their full behavior in terms of decisions and reaction time distributions in baseline as well as distractor inhibition and switch conditions. Furthermore, we predict the individual hemodynamic response timecourse of the rule-representing network and localize it to a frontoparietal network including the inferior frontal junction area and the intraparietal sulcus, using functional magnetic resonance imaging. This refines the understanding of task-switch-related frontoparietal brain activity as reflecting attractor-like working memory representations of task rules. Finally, we estimate the subject-specific stability of the rule-representing attractor states in terms of the minimal action associated with a transition between different rule states in the phase-space of the fitted models. This stability measure correlates with switching-specific thalamocorticostriatal activation, i.e., with a system associated with flexible working memory updating and dopaminergic modulation of cognitive flexibility. These results show that stochastic dynamical systems can implement the basic computations underlying cognitive stability and flexibility and explain neurobiological bases of individual differences. PMID:26068119

    13. Stochastic stacking without filters

      SciTech Connect

      Johnson, R.P.; Marriner, J.

      1982-12-01

      The rate of accumulation of antiprotons is a critical factor in the design of p anti p colliders. A design of a system to accumulate higher anti p fluxes is presented here which is an alternative to the schemes used at the CERN AA and in the Fermilab Tevatron I design. Contrary to these stacking schemes, which use a system of notch filters to protect the dense core of antiprotons from the high power of the stack tail stochastic cooling, an eddy current shutter is used to protect the core in the region of the stack tail cooling kicker. Without filters one can have larger cooling bandwidths, better mixing for stochastic cooling, and easier operational criteria for the power amplifiers. In the case considered here a flux of 1.4 x 10/sup 8/ per sec is achieved with a 4 to 8 GHz bandwidth.

    14. Stochastic speculative price.

      PubMed

      Samuelson, P A

      1971-02-01

      Because a commodity like wheat can be carried forward from one period to the next, speculative arbitrage serves to link its prices at different points of time. Since, however, the size of the harvest depends on complicated probability processes impossible to forecast with certainty, the minimal model for understanding market behavior must involve stochastic processes. The present study, on the basis of the axiom that it is the expected rather than the known-for-certain prices which enter into all arbitrage relations and carryover decisions, determines the behavior of price as the solution to a stochastic-dynamic-programming problem. The resulting stationary time series possesses an ergodic state and normative properties like those often observed for real-world bourses. PMID:16591903

    15. STOCHASTIC COOLING FOR RHIC.

      SciTech Connect

      BLASKIEWICZ,M.BRENNAN,J.M.CAMERON,P.WEI,J.

      2003-05-12

      Emittance growth due to Intra-Beam Scattering significantly reduces the heavy ion luminosity lifetime in RHIC. Stochastic cooling of the stored beam could improve things considerably by counteracting IBS and preventing particles from escaping the rf bucket [1]. High frequency bunched-beam stochastic cooling is especially challenging but observations of Schottky signals in the 4-8 GHz band indicate that conditions are favorable in RHIC [2]. We report here on measurements of the longitudinal beam transfer function carried out with a pickup kicker pair on loan from FNAL TEVATRON. Results imply that for ions a coasting beam description is applicable and we outline some general features of a viable momentum cooling system for RHIC.

    16. STOCHASTIC COOLING POWER REQUIREMENTS.

      SciTech Connect

      WEI,J.BLASKIEWICZ,M.BRENNAN,M.

      2004-07-05

      A practical obstacle for stochastic cooling in high-energy colliders like RHIC is the large amount of power needed for the cooling system. Based on the coasting-beam Fokker-Planck (F-P) equation, we analytically derived the optimum cooling rate and cooling power for a beam of uniform distribution and a cooling system of linear gain function. The results indicate that the usual back-of-envelope formula over-estimated the cooling power by a factor of the mixing factor M. On the other hand, the scaling laws derived from the coasting-beam Fokker-Planck approach agree with those derived from the bunched-beam Fokker-Planck approach if the peak beam intensity is used as the effective coasting-beam intensity. A longitudinal stochastic cooling system of 4-8 GHz bandwidth in RHIC can effectively counteract intrabeam scattering, preventing the beam from escaping the RF bucket becoming debunched around the ring.

    17. Using Commercial Games to Design Teacher-Made Games for the Mathematics Classroom.

      ERIC Educational Resources Information Center

      McBride, John W.; Lamb, Charles E.

      1991-01-01

      The use of commercial games to design and construct games to drill specific mathematics skills is discussed. Game types discussed include card games and board games. Two game boards adapted from "Chutes and Ladders" and "Battleship" are provided. (CW)

    18. Controlling Stochastic Resonance

      NASA Astrophysics Data System (ADS)

      Gammaitoni, Luca; Lcher, Markus; Bulsara, Adi; Hnggi, Peter; Neff, Joseph; Wiesenfeld, Kurt; Ditto, William; Inchiosa, Mario E.

      1999-06-01

      We introduce an open-loop control scheme for stochastic resonators; the scheme permits the enhancement or suppression of the spectral response to threshold-crossing events triggered by a time-periodic signal in background noise. The control is demonstrated in experiments using a Schmitt trigger. A generic two-state theory captures the essential features observed in our experiments and in numerical simulations; this suggests the generality of the effect.

    19. [The choking game: a potentially lethal game].

      PubMed

      Barbera-Marcalain, E; Corrons-Perramon, J; Suelves, J M; Alonso, S Crespo; Castell-Garca, J; Medallo-Muiz, J

      2010-11-01

      Choking games are a known behaviour among adolescents, although they have not been reported in the Spanish scientific literature. They are games which seek a brief euphoria due to the restriction oxygen flow into the brain. The case of a 15 year-old adolescent boy who died in a room due to accidental hanging while playing the choking game is presented. Case characteristics are described and literature reviewed. The choking game is a dangerous and potentially fatal activity. Cases like the one described may be helpful for paediatricians and physicians in recognising this phenomenon and its risks. Knowledge of this activity is important for the prevention and early detection of adolescents risk behaviours. PMID:20678975

    20. Optimal Switching Time

      NASA Astrophysics Data System (ADS)

      Klich, Israel; Levitov, Leonid

      2005-03-01

      We discuss the noise produced in the process of switching mesoscopic conductors between two noiseless states: perfectly connected and disconnected, in the presence of a bias voltage V. We show that there are two main contributions to the noise: a switching noise logarithmic in the time of observation T, and a quantum shot noise accumulated during the process of switching and proportional to V, this leads to a minimization problem for the optimal switching time. Switching noise is expected to be a fundamental parameter in nano-circuits. We also discuss the relation of this result to an estimation of entangelment entropy of a Fermi sea.

    1. REMOTE CONTROLLED SWITCHING DEVICE

      DOEpatents

      Hobbs, J.C.

      1959-02-01

      An electrical switching device which can be remotely controlled and in which one or more switches may be accurately operated at predetermined times or with predetermined intervening time intervals is described. The switching device consists essentially of a deck, a post projecting from the deck at right angles thereto, cam means mounted for rotation around said posts and a switch connected to said deck and actuated by said cam means. Means is provided for rotating the cam means at a constant speed and the switching apparatus is enclosed in a sealed container with external adjusting means and electrical connection elements.

    2. Wolbachia spread dynamics in stochastic environments.

      PubMed

      Hu, Linchao; Huang, Mugen; Tang, Moxun; Yu, Jianshe; Zheng, Bo

      2015-12-01

      Dengue fever is a mosquito-borne viral disease with 100 million people infected annually. A novel strategy for dengue control uses the bacterium Wolbachia to invade dengue vector Aedes mosquitoes. As the impact of environmental heterogeneity on Wolbachia spread dynamics in natural areas has been rarely quantified, we develop a model of differential equations for which the environmental conditions switch randomly between two regimes. We find some striking phenomena that random regime transitions could drive Wolbachia to extinction from certain initial states confirmed Wolbachia fixation in homogeneous environments, and mosquito releasing facilitates Wolbachia invasion more effectively when the regimes transit frequently. By superimposing the phase spaces of the ODE systems defined in each regime, we identify the threshold curves below which Wolbachia invades the whole population, which extends the theory of threshold infection frequency to stochastic environments. PMID:26428255

    3. Inefficiency of voting in Parrondo games

      NASA Astrophysics Data System (ADS)

      Dinís, Luis; Parrondo, Juan M. R.

      2004-11-01

      We study a modification of the so-called Parrondo's paradox where a large number of individuals choose the game they want to play by voting. We show that it can be better for the players to vote randomly than to vote according to their own benefit in one turn. The former yields a winning tendency while the latter results in steady losses. An explanation of this behaviour is given by noting that selfish voting prevents the switching between games that is essential for the total capital to grow. Results for both finite and infinite number of players are presented. It is shown that the extension of the model to the history-dependent Parrondo's paradox also displays the same effect.

    4. Combinatorial optimization games

      SciTech Connect

      Deng, X.; Ibaraki, Toshihide; Nagamochi, Hiroshi

      1997-06-01

      We introduce a general integer programming formulation for a class of combinatorial optimization games, which immediately allows us to improve the algorithmic result for finding amputations in the core (an important solution concept in cooperative game theory) of the network flow game on simple networks by Kalai and Zemel. An interesting result is a general theorem that the core for this class of games is nonempty if and only if a related linear program has an integer optimal solution. We study the properties for this mathematical condition to hold for several interesting problems, and apply them to resolve algorithmic and complexity issues for their cores along the line as put forward in: decide whether the core is empty; if the core is empty, find an imputation in the core; given an imputation x, test whether x is in the core. We also explore the properties of totally balanced games in this succinct formulation of cooperative games.

    5. Educational card games

      NASA Astrophysics Data System (ADS)

      Smith, D. R.; Munro, E.

      2009-09-01

      A number of years have passed since the development of the 'Voyager: Satellites' educational card game reported in Physics Education in 2003. Since then, a large number of copies of the game have been produced and distributed across the UK, to a warm reception from both pupils and teachers. This article reports on some of the feedback received about the game over the five years of the project and gives some examples of how the game has been incorporated into the school curriculum. The recent development of other science-related educational card games that are now available for use in schools is also discussed and it is hoped that this article will give inspiration to others to generate their own educational card games and enjoy some of the positive benefits of 'playing' in the classroom.

    6. Play the Blood Typing Game

      MedlinePLUS

      ... Life and Work Teachers' Questionnaire The Blood Typing Game What happens if you get a blood transfusion ... of the game 2012 Winner of the Best Game Category by Swedish Learning Awards " The winner has ...

    7. Continuum time limit and stationary states of the minority game.

      PubMed

      Marsili, M; Challet, D

      2001-11-01

      We discuss in detail the derivation of stochastic differential equations for the continuum time limit of the minority game. We show that all properties of the minority game can be understood by a careful theoretical analysis of such equations. In particular, (i) we confirm that the stationary state properties are given by the ground state configurations of a disordered (soft) spin system, (ii) we derive the full stationary state distribution, (iii) we characterize the dependence on initial conditions in the symmetric phase, and (iv) we clarify the behavior of the system as a function of the learning rate. This leaves us with a complete and coherent picture of the collective behavior of the minority game. Strikingly we find that the temperaturelike parameter, which is introduced in the choice behavior of individual agents turns out to play the role, at the collective level, of the inverse of a thermodynamic temperature. PMID:11736045

    8. Predictive Game Theory

      NASA Technical Reports Server (NTRS)

      Wolpert, David H.

      2005-01-01

      Probability theory governs the outcome of a game; there is a distribution over mixed strat.'s, not a single "equilibrium". To predict a single mixed strategy must use our loss function (external to the game's players. Provides a quantification of any strategy's rationality. Prove rationality falls as cost of computation rises (for players who have not previously interacted). All extends to games with varying numbers of players.

    9. The Game of Hex

      ERIC Educational Resources Information Center

      Scott, Paul

      2007-01-01

      In this article, the author discusses the game of Hex, including its history, strategies and problems. Like all good games, the rules are very simple. Hex is played on a diamond shaped board made up of hexagons. It can be of any size, but an 11x11 board makes for a good game. Two opposite sides of the diamond are labelled "red," the other two…

    10. The pediatric board game.

      PubMed

      Ogershok, Paul R; Cottrell, Scott

      2004-09-01

      A game was designed to further student learning in the field of pediatric medicine. This educational tool was designed in a board game format. Players advance through the board by answering questions correctly. A total of 400 questions were written with emphasis in content from core pediatric textbooks. Questions were created to encompass four increasingly difficult levels of play. The purpose of this study was to ascertain whether gaming can be a valuable learning experience. During clinical clerkships and rotations in pediatric medicine, both third-year medical students and residents played the game in small-group settings. To date, 37 medical students and 12 residents have completed a post-game survey with a standard 5-point Likert scale. Seven faculties have also played the game and completed the survey. The survey was designed to assess the extent to which students, residents and faculty understood the purpose of the game and agreed that it was a valuable learning experience. The data yielded descriptive statistics for preliminary evaluation of the game. The survey responses suggest that medical students, pediatric residents and faculty observed that the game was a practical and engaging learning experience. The students have universally given high scores to all 10 survey questions. The development of The Pediatric Board Game has been a successful endeavor in medical education. Both educators and learners agree that the board game is a creative and innovative educational tool. Future plans of study will help develop, refine and apply the game to advance students' knowledge of pediatric medicine. PMID:15763827

    11. Game-based telerehabilitation.

      PubMed

      Lange, B; Flynn, Sheryl M; Rizzo, A A

      2009-03-01

      This article summarizes the recent accomplishments and current challenges facing game-based virtual reality (VR) telerehabilitation. Specifically this article addresses accomplishments relative to realistic practice scenarios, part to whole practice, objective measurement of performance and progress, motivation, low cost, interaction devices and game design. Furthermore, a description of the current challenges facing game based telerehabilitation including the packaging, internet capabilities and access, data management, technical support, privacy protection, seizures, distance trials, scientific scrutiny and support from insurance companies. PMID:19282807

    12. Healthy Gaming – Video Game Design to promote Health

      PubMed Central

      Brox, E.; Fernandez-Luque, L.; Tøllefsen, T.

      2011-01-01

      Background There is an increasing interest in health games including simulation tools, games for specific conditions, persuasive games to promote a healthy life style or exergames where physical exercise is used to control the game. Objective The objective of the article is to review current literature about available health games and the impact related to game design principles as well as some educational theory aspects. Methods Literature from the big databases and known sites with games for health has been searched to find articles about games for health purposes. The focus has been on educational games, persuasive games and exergames as well as articles describing game design principles. Results The medical objectives can either be a part of the game theme (intrinsic) or be totally dispatched (extrinsic), and particularly persuasive games seem to use extrinsic game design. Peer support is important, but there is only limited research on multiplayer health games. Evaluation of health games can be both medical and technical, and the focus will depend on the game purpose. Conclusion There is still not enough evidence to conclude which design principles work for what purposes since most of the literature in health serious games does not specify design methodologies, but it seems that extrinsic methods work in persuasion. However, when designing health care games it is important to define both the target group and main objective, and then design a game accordingly using sound game design principles, but also utilizing design elements to enhance learning and persuasion. A collaboration with health professionals from an early design stage is necessary both to ensure that the content is valid and to have the game validated from a clinical viewpoint. Patients need to be involved, especially to improve usability. More research should be done on social aspects in health games, both related to learning and persuasion. PMID:23616865

    13. Stochastic dynamics of macromolecular-assembly networks.

      NASA Astrophysics Data System (ADS)

      Saiz, Leonor; Vilar, Jose

      2006-03-01

      The formation and regulation of macromolecular complexes provides the backbone of most cellular processes, including gene regulation and signal transduction. The inherent complexity of assembling macromolecular structures makes current computational methods strongly limited for understanding how the physical interactions between cellular components give rise to systemic properties of cells. Here we present a stochastic approach to study the dynamics of networks formed by macromolecular complexes in terms of the molecular interactions of their components [1]. Exploiting key thermodynamic concepts, this approach makes it possible to both estimate reaction rates and incorporate the resulting assembly dynamics into the stochastic kinetics of cellular networks. As prototype systems, we consider the lac operon and phage ? induction switches, which rely on the formation of DNA loops by proteins [2] and on the integration of these protein-DNA complexes into intracellular networks. This cross-scale approach offers an effective starting point to move forward from network diagrams, such as those of protein-protein and DNA-protein interaction networks, to the actual dynamics of cellular processes. [1] L. Saiz and J.M.G. Vilar, submitted (2005). [2] J.M.G. Vilar and L. Saiz, Current Opinion in Genetics & Development, 15, 136-144 (2005).

    14. A retrodictive stochastic simulation algorithm

      SciTech Connect

      Vaughan, T.G. Drummond, P.D.; Drummond, A.J.

      2010-05-20

      In this paper we describe a simple method for inferring the initial states of systems evolving stochastically according to master equations, given knowledge of the final states. This is achieved through the use of a retrodictive stochastic simulation algorithm which complements the usual predictive stochastic simulation approach. We demonstrate the utility of this new algorithm by applying it to example problems, including the derivation of likely ancestral states of a gene sequence given a Markovian model of genetic mutation.

    15. Optoelectronic techniques for broadband switching

      NASA Technical Reports Server (NTRS)

      Su, S. F.; Jou, L.; Lenart, J.

      1988-01-01

      Optoelectronic switching employs a hybrid optical/electronic principle to perform the switching function and is applicable for either analog broadband or high-bit rate digital switching. The major advantages of optoelectronic switching include high isolation, low crosstalk, small physical size, light weight, and low power consumption. These advantages make optoelectronic switching an excellent candidate for on-board satellite switching. This paper describes a number of optoelectronic switching architectures. System components required for implementing these switching architectures are discussed. Performance of these architectures are evaluated by calculating their crosstalk, isolation, insertion loss, matrix size, drive power, throughput, and switching speed. Technologies needed for monolithic optoelectronic switching are also identified.

    16. Entanglement Guarantees Emergence of Cooperation in Quantum Prisoner's Dilemma Games on Networks

      PubMed Central

      Li, Angsheng; Yong, Xi

      2014-01-01

      It was known that cooperation of evolutionary prisoner's dilemma games fails to emerge in homogenous networks such as random graphs. Here we proposed a quantum prisoner's dilemma game. The game consists of two players, in which each player has three choices of strategy: cooperator (C), defector (D) and super cooperator (denoted by Q). We found that quantum entanglement guarantees emergence of a new cooperation, the super cooperation of the quantum prisoner's dilemma games, and that entanglement is the mechanism of guaranteed emergence of cooperation of evolutionary prisoner's dilemma games on networks. We showed that for a game with temptation b, there exists a threshold for a measurement of entanglement, beyond which, (super) cooperation of evolutionary quantum prisoner's dilemma games is guaranteed to quickly emerge, giving rise to stochastic convergence of the cooperations, that if the entanglement degree ? is less than the threshold , then the equilibrium frequency of cooperations of the games is positively correlated to the entanglement degree ?, and that if ? is less than and b is beyond some boundary, then the equilibrium frequency of cooperations of the games on random graphs decreases as the average degree of the graphs increases. PMID:25190217

    17. Behavioral variability through stochastic choice and its gating by anterior cingulate cortex.

      PubMed

      Tervo, Dougal G R; Proskurin, Mikhail; Manakov, Maxim; Kabra, Mayank; Vollmer, Alison; Branson, Kristin; Karpova, Alla Y

      2014-09-25

      Behavioral choices that ignore prior experience promote exploration and unpredictability but are seemingly at odds with the brain's tendency to use experience to optimize behavioral choice. Indeed, when faced with virtual competitors, primates resort to strategic counter prediction rather than to stochastic choice. Here, we show that rats also use history- and model-based strategies when faced with similar competitors but can switch to a "stochastic" mode when challenged with a competitor that they cannot defeat by counter prediction. In this mode, outcomes associated with an animal's actions are ignored, and normal engagement of anterior cingulate cortex (ACC) is suppressed. Using circuit perturbations in transgenic rats, we demonstrate that switching between strategic and stochastic behavioral modes is controlled by locus coeruleus input into ACC. Our findings suggest that, under conditions of uncertainty about environmental rules, changes in noradrenergic input alter ACC output and prevent erroneous beliefs from guiding decisions, thus enabling behavioral variation. PAPERCLIP: PMID:25259917

    18. Stochastic predation events and population persistence in bighorn sheep.

      PubMed

      Festa-Bianchet, Marco; Coulson, Tim; Gaillard, Jean-Michel; Hogg, John T; Pelletier, Fanie

      2006-06-22

      Many studies have reported temporal changes in the relative importance of density-dependence and environmental stochasticity in affecting population growth rates, but they typically assume that the predominant factor limiting growth remains constant over long periods of time. Stochastic switches in limiting factors that persist for multiple time-steps have received little attention, but most wild populations may periodically experience such switches. Here, we consider the dynamics of three populations of individually marked bighorn sheep (Ovis canadensis) monitored for 24-28 years. Each population experienced one or two distinct cougar (Puma concolor) predation events leading to population declines. The onset and duration of predation events were stochastic and consistent with predation by specialist individuals. A realistic Markov chain model confirms that predation by specialist cougars can cause extinction of isolated populations. We suggest that such processes may be common. In such cases, predator-prey equilibria may only occur at large geographical and temporal scales, and are unlikely with increasing habitat fragmentation. PMID:16777749

    19. Stochastic predation events and population persistence in bighorn sheep

      PubMed Central

      Festa-Bianchet, Marco; Coulson, Tim; Gaillard, Jean-Michel; Hogg, John T; Pelletier, Fanie

      2006-01-01

      Many studies have reported temporal changes in the relative importance of density-dependence and environmental stochasticity in affecting population growth rates, but they typically assume that the predominant factor limiting growth remains constant over long periods of time. Stochastic switches in limiting factors that persist for multiple time-steps have received little attention, but most wild populations may periodically experience such switches. Here, we consider the dynamics of three populations of individually marked bighorn sheep (Ovis canadensis) monitored for 24–28 years. Each population experienced one or two distinct cougar (Puma concolor) predation events leading to population declines. The onset and duration of predation events were stochastic and consistent with predation by specialist individuals. A realistic Markov chain model confirms that predation by specialist cougars can cause extinction of isolated populations. We suggest that such processes may be common. In such cases, predator–prey equilibria may only occur at large geographical and temporal scales, and are unlikely with increasing habitat fragmentation. PMID:16777749

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

      NASA Astrophysics Data System (ADS)

      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.

    1. Stochastic Flow Cascades

      NASA Astrophysics Data System (ADS)

      Eliazar, Iddo I.; Shlesinger, Michael F.

      2012-01-01

      We introduce and explore a Stochastic Flow Cascade (SFC) model: A general statistical model for the unidirectional flow through a tandem array of heterogeneous filters. Examples include the flow of: (i) liquid through heterogeneous porous layers; (ii) shocks through tandem shot noise systems; (iii) signals through tandem communication filters. The SFC model combines together the Langevin equation, convolution filters and moving averages, and Poissonian randomizations. A comprehensive analysis of the SFC model is carried out, yielding closed-form results. Lvy laws are shown to universally emerge from the SFC model, and characterize both heavy tailed retention times (Noah effect) and long-ranged correlations (Joseph effect).

    2. Stochastic ontogenetic growth model

      NASA Astrophysics Data System (ADS)

      West, B. J.; West, D.

      2012-02-01

      An ontogenetic growth model (OGM) for a thermodynamically closed system is generalized to satisfy both the first and second law of thermodynamics. The hypothesized stochastic ontogenetic growth model (SOGM) is shown to entail the interspecies allometry relation by explicitly averaging the basal metabolic rate and the total body mass over the steady-state probability density for the total body mass (TBM). This is the first derivation of the interspecies metabolic allometric relation from a dynamical model and the asymptotic steady-state distribution of the TBM is fit to data and shown to be inverse power law.

    3. Effective switching frequency multiplier inverter

      DOEpatents

      Su, Gui-Jia (Oak Ridge, TN); Peng, Fang Z. (Okemos, MI)

      2007-08-07

      A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

    4. Police Patrol Game Kit.

      ERIC Educational Resources Information Center

      Clark, Todd, Ed.

      A packet of game materials, designed to help young people better understand what the law is, what the police officer's duties are, and what pressures and fears the police officers experience daily, is presented. The game, designed for a group of 20 to 35 students, contains: Teacher's Manual, Attitude Survey Master, Observer Evaluation Master,…

    5. A Biological Imitation Game.

      PubMed

      Koch, Christof; Buice, Michael A

      2015-10-01

      The digital reconstruction of a slice of rat somatosensory cortex from the Blue Brain Project provides the most complete simulation of a piece of excitable brain matter to date. To place these efforts in context and highlight their strengths and limitations, we introduce a Biological Imitation Game, based on Alan Turing's Imitation Game, that operationalizes the difference between real and simulated brains. PMID:26451478

    6. Games for Teaching Art.

      ERIC Educational Resources Information Center

      Alger, Sandra L. H.

      This teacher's guide gives directions, models, and illustrations for 24 games in art history, criticism, aesthetics, and art production. The games present specific art concepts and vocabulary based on clearly stated objectives and they can be adapted to a variety of lesson types. The goal of each activity is to encourage students to engage in…

    7. Academic Games and Learning.

      ERIC Educational Resources Information Center

      Coleman, James S.

      The aim of this paper is to give some insight into what academic simulation games are, what their goals are, how they accomplish these goals, and how they differ from other ways of teaching and learning. A game is a way of partitioning off a portion of action from the complex stream of life activities. It partitions off a set of players and

    8. Educational Card Games

      ERIC Educational Resources Information Center

      Smith, D. R.; Munro, E.

      2009-01-01

      A number of years have passed since the development of the "Voyager: Satellites" educational card game reported in "Physics Education" in 2003. Since then, a large number of copies of the game have been produced and distributed across the UK, to a warm reception from both pupils and teachers. This article reports on some of the feedback received

    9. Social Interactions and Games

      ERIC Educational Resources Information Center

      Uz, Cigdem; Cagiltay, Kursat

      2015-01-01

      Digital games have become popular due to great technological improvements in recent years. They have been increasingly transformed from co-located experiences into multi-played, socially oriented platforms (Herodotou, 2009). Multi-User Online Games provide the opportunity to create a social environment for friendships and strengthen the…

    10. Great Games That Disappeared

      ERIC Educational Resources Information Center

      Rauschenbach, James; Swartz, Daniel R.

      2016-01-01

      Sometimes through a single person's efforts, a new and innovative game is developed and promoted locally. Occasionally, circumstances cause these games to remain on a local level without being adopted by mainstream physical educators and physical activity professionals. Unfortunately, some educators tend to stick to what they know and teach…

    11. Cournot and Bertrand Games.

      ERIC Educational Resources Information Center

      Beckman, Steven R.

      2003-01-01

      Describes a series of matrix choice games that illustrate for students the concepts of monopoly, shared monopoly, Cournot, Bertrand, and Stackelberg behavior given either perfect complements or perfect substitutes. Suggests that the use of the games also allows for student dialogue about international trade and price wars. (JEH)

    12. Environmental Education Games.

      ERIC Educational Resources Information Center

      Pennsylvania State Dept. of Education, Harrisburg. Bureau of General and Academic Education.

      Six environmental education simulation games are presented in this manual, developed by Project SESAME G (Susquehanna ESEA Synergetic Activities for Maximal-involvement via Education Games). The simulations are models of social situations which provide an opportunity for social interaction in the classroom, maximize student involvement, and change

    13. Games on Sustainable Development

      ERIC Educational Resources Information Center

      Meadows, Dennis L.; Van der Waals, Barbara

      This booklet contains a collection of educational games that can be used by teachers to convey ideas and create discussion related to environmental protection and sustainable development. The games accommodate participants of all ages and require little preparation by the teacher, up to 30-40 players with only one operator, minimal materials (many

    14. CBT Fun and Games.

      ERIC Educational Resources Information Center

      Fister, Sarah

      1999-01-01

      Use of games in computer-based training (CBT) can enliven material, encourage discovery and experiential learning, and make visceral connections for learners. However, humor can offend or wear thin, and games can be perceived as playing rather than as learning. (JOW)

    15. Game Theory .net.

      ERIC Educational Resources Information Center

      Shor, Mikhael

      2003-01-01

      States making game theory relevant and accessible to students is challenging. Describes the primary goal of GameTheory.net is to provide interactive teaching tools. Indicates the site strives to unite educators from economics, political and computer science, and ecology by providing a repository of lecture notes and tests for courses using

    16. Games People Play

      ERIC Educational Resources Information Center

      VerBruggen, Robert

      2012-01-01

      Today's video games aren't even a little bit like the ones that came out a few decades ago. Not only has the underlying technology dramatically improved, but the medium has matured remarkably in the years since "Pong" and "Space Invaders." ruled the arcades. The artistic promise of video games has yet to be fulfilled. The current state of the

    17. The Chinese House Game.

      ERIC Educational Resources Information Center

      Lee, James R.

      1989-01-01

      Discussion of the use of simulations to teach international relations (IR) highlights the Chinese House Game, a computer-based decision-making game based on Inter Nation Simulation (INS). Topics discussed include the increasing role of artificial intelligence in IR simulations, multi-disciplinary approaches, and the direction of IR as a

    18. Educational Card Games

      ERIC Educational Resources Information Center

      Smith, D. R.; Munro, E.

      2009-01-01

      A number of years have passed since the development of the "Voyager: Satellites" educational card game reported in "Physics Education" in 2003. Since then, a large number of copies of the game have been produced and distributed across the UK, to a warm reception from both pupils and teachers. This article reports on some of the feedback received…

    19. Games and childhood obesity

      Technology Transfer Automated Retrieval System (TEKTRAN)

      Videogames can be used to help children change their obesity-related diet and physical activity behaviors. A review of the relevant literature in this special issue of the Games for Health Journal indicated that video games did influence children's adiposity, but only among children who were alread...

    20. The Guppy Game

      ERIC Educational Resources Information Center

      Blattner, Margaret; Hug, Barbara; Watson, Patrick; Korol, Donna

      2012-01-01

      Adaptation, interactions between species and their environments, and change over time are fundamental principles in biology. They represent aspects of two of the big ideas in science: evolution and natural selection. To help students understand these ideas, the authors developed the "Guppy Game." In this article, they describe the game and how

    1. Gaming and Gamification

      ERIC Educational Resources Information Center

      Mallon, Melissa

      2013-01-01

      The New Media Consortium's "Horizon Report" for higher education cites games and gamification with a time-to-adoption of two to three years. The use of digital games is almost ubiquitous in social media and is swiftly gaining popularity in other industries as well. Many in higher education have embraced gamification due to its

    2. Great Games That Disappeared

      ERIC Educational Resources Information Center

      Rauschenbach, James; Swartz, Daniel R.

      2016-01-01

      Sometimes through a single person's efforts, a new and innovative game is developed and promoted locally. Occasionally, circumstances cause these games to remain on a local level without being adopted by mainstream physical educators and physical activity professionals. Unfortunately, some educators tend to stick to what they know and teach

    3. Gaming and Gamification

      ERIC Educational Resources Information Center

      Mallon, Melissa

      2013-01-01

      The New Media Consortium's "Horizon Report" for higher education cites games and gamification with a time-to-adoption of two to three years. The use of digital games is almost ubiquitous in social media and is swiftly gaining popularity in other industries as well. Many in higher education have embraced gamification due to its…

    4. The Guppy Game

      ERIC Educational Resources Information Center

      Blattner, Margaret; Hug, Barbara; Watson, Patrick; Korol, Donna

      2012-01-01

      Adaptation, interactions between species and their environments, and change over time are fundamental principles in biology. They represent aspects of two of the big ideas in science: evolution and natural selection. To help students understand these ideas, the authors developed the "Guppy Game." In this article, they describe the game and how…

    5. Skill Games for Mathematics.

      ERIC Educational Resources Information Center

      Corle, Clyde G.

      This guide is to assist teachers with motivational ideas for teaching elementary school mathematics. The items included are a wide variety of games (paper and pencil, verbal, and physical), jingles, contests, teaching devices, and thought provoking exercises. Suggestions for selection of mathematical games are offered. The devices are used to…

    6. The Clean Air Game.

      ERIC Educational Resources Information Center

      Avalone-King, Deborah

      2000-01-01

      Introduces the Clean Air game which teaches about air quality and its vital importance for life. Introduces students to air pollutants, health of people and environment, and possible actions individuals can take to prevent air pollution. Includes directions for the game. (YDS)

    7. The Frozen Price Game

      ERIC Educational Resources Information Center

      Alden, Lori

      2003-01-01

      In this article, the author discusses the educational frozen price game she developed to teach the basic economic principle of price allocation. In addition to demonstrating the advantages of price allocation, the game also illustrates such concepts as opportunity costs, cost benefit comparisons, and the trade-off between efficiency and equity.

    8. Gaming in Technology Education

      ERIC Educational Resources Information Center

      Clark, Aaron C.; Ernst, Jeremy V.

      2009-01-01

      The authors have devoted a considerable amount of time evaluating the role that gaming and game development plays in the form of curricula integration and as a future career focus for students interested in this field. From the research conducted through the completed National Science Foundation (NSF) project, VisTE: Visualization in Technology

    9. Solid state switch

      DOEpatents

      Merritt, Bernard T. (Livermore, CA); Dreifuerst, Gary R. (Livermore, CA)

      1994-01-01

      A solid state switch, with reverse conducting thyristors, is designed to operate at 20 kV hold-off voltage, 1500 A peak, 1.0 .mu.s pulsewidth, and 4500 pps, to replace thyratrons. The solid state switch is more reliable, more economical, and more easily repaired. The switch includes a stack of circuit card assemblies, a magnetic assist and a trigger chassis. Each circuit card assembly contains a reverse conducting thyristor, a resistor capacitor network, and triggering circuitry.

    10. Thermally actuated thermionic switch

      DOEpatents

      Barrus, D.M.; Shires, C.D.

      1982-09-30

      A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

    11. Analytical description for the critical fixations of evolutionary coordination games on finite complex structured populations

      NASA Astrophysics Data System (ADS)

      Zhang, Liye; Zou, Yong; Guan, Shuguang; Liu, Zonghua

      2015-04-01

      Evolutionary game theory is crucial to capturing the characteristic interaction patterns among selfish individuals. In a population of coordination games of two strategies, one of the central problems is to determine the fixation probability that the system reaches a state of networkwide of only one strategy, and the corresponding expectation times. The deterministic replicator equations predict the critical value of initial density of one strategy, which separates the two absorbing states of the system. However, numerical estimations of this separatrix show large deviations from the theory in finite populations. Here we provide a stochastic treatment of this dynamic process on complex networks of finite sizes as Markov processes, showing the evolutionary time explicitly. We describe analytically the effects of network structures on the intermediate fixations as observed in numerical simulations. Our theoretical predictions are validated by various simulations on both random and scale free networks. Therefore, our stochastic framework can be helpful in dealing with other networked game dynamics.

    12. Analytical description for the critical fixations of evolutionary coordination games on finite complex structured populations.

      PubMed

      Zhang, Liye; Zou, Yong; Guan, Shuguang; Liu, Zonghua

      2015-04-01

      Evolutionary game theory is crucial to capturing the characteristic interaction patterns among selfish individuals. In a population of coordination games of two strategies, one of the central problems is to determine the fixation probability that the system reaches a state of networkwide of only one strategy, and the corresponding expectation times. The deterministic replicator equations predict the critical value of initial density of one strategy, which separates the two absorbing states of the system. However, numerical estimations of this separatrix show large deviations from the theory in finite populations. Here we provide a stochastic treatment of this dynamic process on complex networks of finite sizes as Markov processes, showing the evolutionary time explicitly. We describe analytically the effects of network structures on the intermediate fixations as observed in numerical simulations. Our theoretical predictions are validated by various simulations on both random and scale free networks. Therefore, our stochastic framework can be helpful in dealing with other networked game dynamics. PMID:25974547

    13. Reusable fast opening switch

      DOEpatents

      Van Devender, J.P.; Emin, D.

      1983-12-21

      A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and metallic states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

    14. Reusable fast opening switch

      DOEpatents

      Van Devender, John P. (Albuquerque, NM); Emin, David (Albuquerque, NM)

      1986-01-01

      A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and insulating states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

    15. Alarm toe switch

      DOEpatents

      Ganyard, Floyd P. (Albuquerque, NM)

      1982-01-01

      An alarm toe switch inserted within a shoe for energizing an alarm circuit n a covert manner includes an insole mounting pad into which a miniature reed switch is fixedly molded. An elongated slot perpendicular to the reed switch is formed in the bottom surface of the mounting pad. A permanent cylindrical magnet positioned in the forward portion of the slot with a diameter greater than the pad thickness causes a bump above the pad. A foam rubber block is also positioned in the slot rearwardly of the magnet and holds the magnet in normal inoperative relation. A non-magnetic support plate covers the slot and holds the magnet and foam rubber in the slot. The plate minimizes bending and frictional forces to improve movement of the magnet for reliable switch activation. The bump occupies the knuckle space beneath the big toe. When the big toe is scrunched rearwardly the magnet is moved within the slot relative to the reed switch, thus magnetically activating the switch. When toe pressure is released the foam rubber block forces the magnet back into normal inoperative position to deactivate the reed switch. The reed switch is hermetically sealed with the magnet acting through the wall so the switch assembly S is capable of reliable operation even in wet and corrosive environments.

    16. Avatars in Analytical Gaming

      SciTech Connect

      Cowell, Andrew J.; Cowell, Amanda K.

      2009-08-29

      This paper discusses the design and use of anthropomorphic computer characters as nonplayer characters (NPC’s) within analytical games. These new environments allow avatars to play a central role in supporting training and education goals instead of planning the supporting cast role. This new ‘science’ of gaming, driven by high-powered but inexpensive computers, dedicated graphics processors and realistic game engines, enables game developers to create learning and training opportunities on par with expensive real-world training scenarios. However, there needs to be care and attention placed on how avatars are represented and thus perceived. A taxonomy of non-verbal behavior is presented and its application to analytical gaming discussed.

    17. Stochastic power flow modeling

      SciTech Connect

      Not Available

      1980-06-01

      The stochastic nature of customer demand and equipment failure on large interconnected electric power networks has produced a keen interest in the accurate modeling and analysis of the effects of probabilistic behavior on steady state power system operation. The principle avenue of approach has been to obtain a solution to the steady state network flow equations which adhere both to Kirchhoff's Laws and probabilistic laws, using either combinatorial or functional approximation techniques. Clearly the need of the present is to develop sound techniques for producing meaningful data to serve as input. This research has addressed this end and serves to bridge the gap between electric demand modeling, equipment failure analysis, etc., and the area of algorithm development. Therefore, the scope of this work lies squarely on developing an efficient means of producing sensible input information in the form of probability distributions for the many types of solution algorithms that have been developed. Two major areas of development are described in detail: a decomposition of stochastic processes which gives hope of stationarity, ergodicity, and perhaps even normality; and a powerful surrogate probability approach using proportions of time which allows the calculation of joint events from one dimensional probability spaces.

    18. Stochastic morphological evolution equations

      NASA Astrophysics Data System (ADS)

      Kloeden, Peter E.; Lorenz, Thomas

      The inadequacy of locally defined set-valued differential equations to describe the evolution of shapes and morphological forms in biology, which are usually neither convex or nondecreasing, was recognised by J.-P. Aubin, who introduced morphological evolution equations, which are essentially nonlocally defined set-valued differential equations with the inclusion vector field also depending on the entire reachable set. This concept is extended here to the stochastic setting of set-valued It evolution equations in Hilbert spaces. Due to the nonanticipative nature of It calculus, the evolving reachable sets are nonanticipative nonempty closed random sets. The existence of solutions and their dependence on initial data are established. The latter requires the introduction of a time-oriented semi-metric in time-space variables. As a consequence the stochastic morphological evolution equations generate a deterministic nonautonomous dynamical system formulated as a two-parameter semigroup with the complication that the random subsets take values in different spaces at different time instances due to the nonanticipativity requirement. It is also shown how nucleation processes can be handled in this conceptual framework.

    19. On the efficacy of stochastic collocation, stochastic Galerkin, and stochastic reduced order models for solving stochastic problems

      SciTech Connect

      Richard V. Field, Jr.; Emery, John M.; Grigoriu, Mircea Dan

      2015-05-19

      The stochastic collocation (SC) and stochastic Galerkin (SG) methods are two well-established and successful approaches for solving general stochastic problems. A recently developed method based on stochastic reduced order models (SROMs) can also be used. Herein we provide a comparison of the three methods for some numerical examples; our evaluation only holds for the examples considered in the paper. The purpose of the comparisons is not to criticize the SC or SG methods, which have proven very useful for a broad range of applications, nor is it to provide overall ratings of these methods as compared to the SROM method. Furthermore, our objectives are to present the SROM method as an alternative approach to solving stochastic problems and provide information on the computational effort required by the implementation of each method, while simultaneously assessing their performance for a collection of specific problems.

    20. On the efficacy of stochastic collocation, stochastic Galerkin, and stochastic reduced order models for solving stochastic problems

      DOE PAGESBeta

      Richard V. Field, Jr.; Emery, John M.; Grigoriu, Mircea Dan

      2015-05-19

      The stochastic collocation (SC) and stochastic Galerkin (SG) methods are two well-established and successful approaches for solving general stochastic problems. A recently developed method based on stochastic reduced order models (SROMs) can also be used. Herein we provide a comparison of the three methods for some numerical examples; our evaluation only holds for the examples considered in the paper. The purpose of the comparisons is not to criticize the SC or SG methods, which have proven very useful for a broad range of applications, nor is it to provide overall ratings of these methods as compared to the SROM method.more » Furthermore, our objectives are to present the SROM method as an alternative approach to solving stochastic problems and provide information on the computational effort required by the implementation of each method, while simultaneously assessing their performance for a collection of specific problems.« less

    1. Transient-Switch-Signal Suppressor

      NASA Technical Reports Server (NTRS)

      Bozeman, Richard J., Jr.

      1995-01-01

      Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

    2. Gene regulation and noise reduction by coupling of stochastic processes

      NASA Astrophysics Data System (ADS)

      Ramos, Alexandre F.; Hornos, José Eduardo M.; Reinitz, John

      2015-02-01

      Here we characterize the low-noise regime of a stochastic model for a negative self-regulating binary gene. The model has two stochastic variables, the protein number and the state of the gene. Each state of the gene behaves as a protein source governed by a Poisson process. The coupling between the two gene states depends on protein number. This fact has a very important implication: There exist protein production regimes characterized by sub-Poissonian noise because of negative covariance between the two stochastic variables of the model. Hence the protein numbers obey a probability distribution that has a peak that is sharper than those of the two coupled Poisson processes that are combined to produce it. Biochemically, the noise reduction in protein number occurs when the switching of the genetic state is more rapid than protein synthesis or degradation. We consider the chemical reaction rates necessary for Poisson and sub-Poisson processes in prokaryotes and eucaryotes. Our results suggest that the coupling of multiple stochastic processes in a negative covariance regime might be a widespread mechanism for noise reduction.

    3. Multi-scenario modelling of uncertainty in stochastic chemical systems

      SciTech Connect

      Evans, R. David; Ricardez-Sandoval, Luis A.

      2014-09-15

      Uncertainty analysis has not been well studied at the molecular scale, despite extensive knowledge of uncertainty in macroscale systems. The ability to predict the effect of uncertainty allows for robust control of small scale systems such as nanoreactors, surface reactions, and gene toggle switches. However, it is difficult to model uncertainty in such chemical systems as they are stochastic in nature, and require a large computational cost. To address this issue, a new model of uncertainty propagation in stochastic chemical systems, based on the Chemical Master Equation, is proposed in the present study. The uncertain solution is approximated by a composite state comprised of the averaged effect of samples from the uncertain parameter distributions. This model is then used to study the effect of uncertainty on an isomerization system and a two gene regulation network called a repressilator. The results of this model show that uncertainty in stochastic systems is dependent on both the uncertain distribution, and the system under investigation. -- Highlights: A method to model uncertainty on stochastic systems was developed. The method is based on the Chemical Master Equation. Uncertainty in an isomerization reaction and a gene regulation network was modelled. Effects were significant and dependent on the uncertain input and reaction system. The model was computationally more efficient than Kinetic Monte Carlo.

    4. Stochastic transitions in a bistable reaction system on the membrane

      PubMed Central

      Kocha?czyk, Marek; Jaruszewicz, Joanna; Lipniacki, Tomasz

      2013-01-01

      Transitions between steady states of a multi-stable stochastic system in the perfectly mixed chemical reactor are possible only because of stochastic switching. In realistic cellular conditions, where diffusion is limited, transitions between steady states can also follow from the propagation of travelling waves. Here, we study the interplay between the two modes of transition for a prototype bistable system of kinasephosphatase interactions on the plasma membrane. Within microscopic kinetic Monte Carlo simulations on the hexagonal lattice, we observed that for finite diffusion the behaviour of the spatially extended system differs qualitatively from the behaviour of the same system in the well-mixed regime. Even when a small isolated subcompartment remains mostly inactive, the chemical travelling wave may propagate, leading to the activation of a larger compartment. The activating wave can be induced after a small subdomain is activated as a result of a stochastic fluctuation. Such a spontaneous onset of activity is radically more probable in subdomains characterized by slower diffusion. Our results show that a local immobilization of substrates can lead to the global activation of membrane proteins by the mechanism that involves stochastic fluctuations followed by the propagation of a semi-deterministic travelling wave. PMID:23635492

    5. Stages for Children Inventing Games

      ERIC Educational Resources Information Center

      Butler, Joy

      2013-01-01

      This article offers practical advice for teachers interested in using Inventing Games (IG) as a way to facilitate learning about game structures, rules, and the principles of fair play that they can apply not only to game play, but to everyday life as members of a democratically organized society. Inventing Games gives students the opportunity to…

    6. Teaching Game Sense in Soccer

      ERIC Educational Resources Information Center

      Pill, Shane

      2012-01-01

      "Game sense" is a sport-specific iteration of the teaching games for understanding model, designed to balance physical development of motor skill and fitness with the development of game understanding. Game sense can foster a shared vision for sport learning that bridges school physical education and community sport. This article explains how to…

    7. Situating Ethics in Games Education

      ERIC Educational Resources Information Center

      Butler, Joy

      2013-01-01

      This paper posits that Inventing Games (IG), an aspect of the games curriculum based on principles of Teaching Games for Understanding (TGfU), opens up important spaces for teaching social and ethical understanding. Games have long been regarded as a site for moral development. For most teachers, however, ethical principles have been seen as…

    8. Play Chinese Games. 1987, Revised.

      ERIC Educational Resources Information Center

      White, Caryn

      This document, designed to introduce all ages to a selection of popular Chinese games, describes these games and provides instructions and materials for making the items needed to play most of them. Section 1 suggests class activities that can be related to some of the games. Section 2 presents instructions for the physical or outdoor games of:

    9. Video Games and Civic Engagement

      ERIC Educational Resources Information Center

      Perkins-Gough, Deborah

      2009-01-01

      According to a national telephone survey by the Pew Internet Project, 99 percent of boys and 94 percent of girls ages 12-17 play computer, Web, portable, or console games; and 50 percent play such games daily. The survey report, Teens, Video Games, and Civics, examines the extent and nature of teens' game playing and sheds some light on the

    10. Simple Games . . . or Are They?

      ERIC Educational Resources Information Center

      Arn, Susan Kyle

      2006-01-01

      Students today begin using computers and playing video games as early as two years old. The technology behind these games is more complicated than most people can imagine. In this article, the author presents some simple number games which seem easy at the beginning, but as the games are repeated, mathematical content becomes more of the focus…

    11. Stages for Children Inventing Games

      ERIC Educational Resources Information Center

      Butler, Joy

      2013-01-01

      This article offers practical advice for teachers interested in using Inventing Games (IG) as a way to facilitate learning about game structures, rules, and the principles of fair play that they can apply not only to game play, but to everyday life as members of a democratically organized society. Inventing Games gives students the opportunity to

    12. Teaching Game Sense in Soccer

      ERIC Educational Resources Information Center

      Pill, Shane

      2012-01-01

      "Game sense" is a sport-specific iteration of the teaching games for understanding model, designed to balance physical development of motor skill and fitness with the development of game understanding. Game sense can foster a shared vision for sport learning that bridges school physical education and community sport. This article explains how to

    13. The Terrific Technicolor Action Game.

      ERIC Educational Resources Information Center

      Guhin, Paula

      2002-01-01

      Describes a game that focuses on the color wheel and other topics that can be used with upper-elementary or middle school students as a test review. Includes lists of the game rules, what is needed for the game, and suggested questions for the game. (CMK)

    14. Simple Games . . . or Are They?

      ERIC Educational Resources Information Center

      Arn, Susan Kyle

      2006-01-01

      Students today begin using computers and playing video games as early as two years old. The technology behind these games is more complicated than most people can imagine. In this article, the author presents some simple number games which seem easy at the beginning, but as the games are repeated, mathematical content becomes more of the focus

    15. Third-order leader-following consensus with circumstance noise under impulsive and switching control

      NASA Astrophysics Data System (ADS)

      Sun, Mei; Han, Dun; Li, Dandan; Jia, Qiang; Wang, Yaqi

      2014-02-01

      This research is aimed at investigating the leader-follower problem of third-order multi-agent with noise perturbation over fixed network under impulsive and switching control. Based on stochastic differential equation theory and hybrid control theory, effective impulsive and switching controllers are proposed, and the sufficient conditions for reaching multi-agent leader-following consensus are acquired. Numerical simulations verify the validity of the theoretical research results.

    16. Asymmetrical Switch Costs in Children

      ERIC Educational Resources Information Center

      Ellefson, Michelle R.; Shapiron, Laura R.; Chater, Nick

      2006-01-01

      Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about

    17. Multiobjective optimization in structural design with uncertain parameters and stochastic processes

      NASA Technical Reports Server (NTRS)

      Rao, S. S.

      1984-01-01

      The application of multiobjective optimization techniques to structural design problems involving uncertain parameters and random processes is studied. The design of a cantilever beam with a tip mass subjected to a stochastic base excitation is considered for illustration. Several of the problem parameters are assumed to be random variables and the structural mass, fatigue damage, and negative of natural frequency of vibration are considered for minimization. The solution of this three-criteria design problem is found by using global criterion, utility function, game theory, goal programming, goal attainment, bounded objective function, and lexicographic methods. It is observed that the game theory approach is superior in finding a better optimum solution, assuming the proper balance of the various objective functions. The procedures used in the present investigation are expected to be useful in the design of general dynamic systems involving uncertain parameters, stochastic process, and multiple objectives.

    18. On Path Attractors, Stochastic Bifurcation and Dephasing In Genetic Networks

      NASA Astrophysics Data System (ADS)

      Potoyan, Davit

      2015-03-01

      Gene regulatory networks are driven stochastic systems with the noise having two distinct components due to the to birth and death of metabolite molecules and dichotomous nature of gene state switching. Presence of dichotomous gene noise alone has the capacity to significantly perturb the optimal transition paths and steady state probability distributions compared to the macroscopic models and their weak noise approximations. Most importantly dichotomous gene noise can also lead to multimodal distributions due to stochastic bifurcation of the underlying nonlinear dynamical system, which underlies the mechanism of formation of population heterogeneity. In this note we derive approximate path based expression of the time dependent probability of gene circuits which enables deeper exploration of the role of gene noise in formation of epigenetic states and dephasing-like phenomena.

    19. Leading the Game, Losing the Competition: Identifying Leaders and Followers in a Repeated Game

      PubMed Central

      Seip, Knut Lehre; Grøn, Øyvind

      2016-01-01

      We explore a new method for identifying leaders and followers, LF, in repeated games by analyzing an experimental, repeated (50 rounds) game where Row player shifts the payoff between small and large values–a type of “investor” and Column player determines who gets the payoff–a type of “manager”. We found that i) the Investor (Row) most often is a leading player and the manager (Column) a follower. The longer the Investor leads the game, the higher is both player’s payoff. Surprisingly however, it is always the Manager that achieves the largest payoff. ii) The game has an efficient cooperative strategy where the players alternate in receiving a high payoff, but the players never identify, or accept, that strategy. iii) Under the assumption that the information used by the players is closely associated with the leader- follower sequence, and that information is available before the player’s decisions are made, the players switched LF- strategy primarily as a function of information on the Investor’s investment and moves and secondly as a function of the Manager’s payoff. PMID:26968032

    20. Leading the Game, Losing the Competition: Identifying Leaders and Followers in a Repeated Game.

      PubMed

      Seip, Knut Lehre; Grøn, Øyvind

      2016-01-01

      We explore a new method for identifying leaders and followers, LF, in repeated games by analyzing an experimental, repeated (50 rounds) game where Row player shifts the payoff between small and large values-a type of "investor" and Column player determines who gets the payoff-a type of "manager". We found that i) the Investor (Row) most often is a leading player and the manager (Column) a follower. The longer the Investor leads the game, the higher is both player's payoff. Surprisingly however, it is always the Manager that achieves the largest payoff. ii) The game has an efficient cooperative strategy where the players alternate in receiving a high payoff, but the players never identify, or accept, that strategy. iii) Under the assumption that the information used by the players is closely associated with the leader- follower sequence, and that information is available before the player's decisions are made, the players switched LF- strategy primarily as a function of information on the Investor's investment and moves and secondly as a function of the Manager's payoff. PMID:26968032

    1. Population balancing with species switching

      NASA Astrophysics Data System (ADS)

      Song, Juyong; Jo, Junghyo; Hoang, Danh-Tai; Kim, Jongwook

      2014-07-01

      Biological organisms are composed of cells differentiated from stem cells. Emerging evidence suggests phenotypic switches of differentiated cells, called transdifferentiation, during development and under pathophysiological conditions. To examine the role of transdifferentiation for population balances, we construct a stochastic model mapped into urn problems. When a colored ball is drawn from an urn, one additional ball with the same color is put into the urn in Polya's urn scheme while the drawn ball is replaced by another ball with different color in Ehrenfest's urn scheme. Our population balance model is a mixture of the two classic urn problems corresponding to cell replication and transdifferentiation. Because a dominant population is more likely to be drawn, the preferential replication and transdifferentiation of the dominant population contribute to increasing and decreasing the gap between the two populations, respectively. Therefore, their competition determines population balancing. We analyze the dependence of population dynamics on the replication and the transdifferentiation rates of each population. Finally, experimentally probing the event of transdifferentiation is a challenging problem because it is indistinguishable from death of one cell type and concurrent replication of another cell type. Our analysis suggests that transdifferentiation generates fewer fluctuations in population dynamics than the combined events of cell death and replication do.

    2. Effects of adaptive dynamical linking in networked games.

      PubMed

      Yang, Zhihu; Li, Zhi; Wu, Te; Wang, Long

      2013-10-01

      The role of dynamical topologies in the evolution of cooperation has received considerable attention, as some studies have demonstrated that dynamical networks are much better than static networks in terms of boosting cooperation. Here we study a dynamical model of evolution of cooperation on stochastic dynamical networks in which there are no permanent partners to each agent. Whenever a new link is created, its duration is randomly assigned without any bias or preference. We allow the agent to adaptively adjust the duration of each link during the evolution in accordance with the feedback from game interactions. By Monte Carlo simulations, we find that cooperation can be remarkably promoted by this adaptive dynamical linking mechanism both for the game of pairwise interactions, such as the Prisoner's Dilemma game (PDG), and for the game of group interactions, illustrated by the public goods game (PGG). And the faster the adjusting rate, the more successful the evolution of cooperation. We also show that in this context weak selection favors cooperation much more than strong selection does. What is particularly meaningful is that the prosperity of cooperation in this study indicates that the rationality and selfishness of a single agent in adjusting social ties can lead to the progress of altruism of the whole population. PMID:24229137

    3. Effects of adaptive dynamical linking in networked games

      NASA Astrophysics Data System (ADS)

      Yang, Zhihu; Li, Zhi; Wu, Te; Wang, Long

      2013-10-01

      The role of dynamical topologies in the evolution of cooperation has received considerable attention, as some studies have demonstrated that dynamical networks are much better than static networks in terms of boosting cooperation. Here we study a dynamical model of evolution of cooperation on stochastic dynamical networks in which there are no permanent partners to each agent. Whenever a new link is created, its duration is randomly assigned without any bias or preference. We allow the agent to adaptively adjust the duration of each link during the evolution in accordance with the feedback from game interactions. By Monte Carlo simulations, we find that cooperation can be remarkably promoted by this adaptive dynamical linking mechanism both for the game of pairwise interactions, such as the Prisoner's Dilemma game (PDG), and for the game of group interactions, illustrated by the public goods game (PGG). And the faster the adjusting rate, the more successful the evolution of cooperation. We also show that in this context weak selection favors cooperation much more than strong selection does. What is particularly meaningful is that the prosperity of cooperation in this study indicates that the rationality and selfishness of a single agent in adjusting social ties can lead to the progress of altruism of the whole population.

    4. Reflective HTS switch

      DOEpatents

      Martens, Jon S. (Albuquerque, NM); Hietala, Vincent M. (Placitas, NM); Hohenwarter, Gert K. G. (Madison, WI)

      1994-01-01

      A HTS switch includes a HTS conductor for providing a superconducting path for an electrical signal and an serpentine wire actuator for controllably heating a portion of the conductor sufficiently to cause that portion to have normal, and not superconducting, resistivity. Mass of the portion is reduced to decrease switching time.

    5. Power-Switching Circuit

      NASA Technical Reports Server (NTRS)

      Praver, Gerald A.; Theisinger, Peter C.; Genofsky, John

      1987-01-01

      Functions of circuit breakers, meters, and switches combined. Circuit that includes power field-effect transistors (PFET's) provides on/off switching, soft starting, current monitoring, current tripping, and protection against overcurrent for 30-Vdc power supply at normal load currents up to 2 A. Has no moving parts.

    6. Reflective HTS switch

      DOEpatents

      Martens, J.S.; Hietala, V.M.; Hohenwarter, G.K.G.

      1994-09-27

      A HTS (High Temperature Superconductor) switch includes a HTS conductor for providing a superconducting path for an electrical signal and an serpentine wire actuator for controllably heating a portion of the conductor sufficiently to cause that portion to have normal, and not superconducting, resistivity. Mass of the portion is reduced to decrease switching time. 6 figs.

    7. Asymmetric Evolutionary Games

      PubMed Central

      McAvoy, Alex; Hauert, Christoph

      2015-01-01

      Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoners Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games. PMID:26308326

    8. Exploring Game Experiences and Game Leadership in Massively Multiplayer Online Role-Playing Games

      ERIC Educational Resources Information Center

      Jang, YeiBeech; Ryu, SeoungHo

      2011-01-01

      This study explored the in-game experiences of massively multiplayer online role-playing game (MMORPG) players focusing on game leadership and offline leadership. MMORPGs have enormous potential to provide gameplayers with rich social experiences through various interactions along with social activities such as joining a game community, team play

    9. Erected mirror optical switch

      DOEpatents

      Allen, James J.

      2005-06-07

      A microelectromechanical (MEM) optical switching apparatus is disclosed that is based on an erectable mirror which is formed on a rotatable stage using surface micromachining. An electrostatic actuator is also formed on the substrate to rotate the stage and mirror with a high angular precision. The mirror can be erected manually after fabrication of the device and used to redirect an incident light beam at an arbitrary angel and to maintain this state in the absence of any applied electrical power. A 1.times.N optical switch can be formed using a single rotatable mirror. In some embodiments of the present invention, a plurality of rotatable mirrors can be configured so that the stages and mirrors rotate in unison when driven by a single micromotor thereby forming a 2.times.2 optical switch which can be used to switch a pair of incident light beams, or as a building block to form a higher-order optical switch.

    10. Nanoscale memristive radiofrequency switches

      NASA Astrophysics Data System (ADS)

      Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C.; Xia, Qiangfei

      2015-06-01

      Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 1012 with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications.

    11. Stochastic geometry of turbulence

      NASA Astrophysics Data System (ADS)

      Falkovich, Gregory

      2012-02-01

      Geometric statistics open the window into the most fundamental aspect of turbulence flows, their symmetries, both broken and emerging. On one hand, the study of the stochastic geometry of multi-point configurations reveals the statistical conservation laws which are responsible for the breakdown of scale invariance in direct turbulence cascades. On the other hand, the numerical and experimental studies of inverse cascade reveal that some families of isolines can be mapped to a Brownian walk (i.e. belong to the so-called SLE class) and are thus not only scale invariant but conformally invariant. That means that some aspects of turbulence statistics can be probably described by a conformal field theory. The talk is a review of broken and emerging symmetries in turbulence statistics.

    12. Knowledge discovery through games and game theory

      NASA Astrophysics Data System (ADS)

      Smith, James F., III; Rhyne, Robert D.

      2001-03-01

      A fuzzy logic based expert system has been developed that automatically allocates electronic attack (EA) resources in real-time over many dissimilar platforms. The platforms can be very general, e.g., ships, planes, robots, land based facilities, etc. Potential foes the platforms deal with can also be general. The initial version of the algorithm was optimized using a genetic algorithm employing fitness functions constructed based on expertise. A new approach is being explored that involves embedding the resource manager in a electronic game environment. The game allows a human expert to play against the resource manager in a simulated battlespace with each of the defending platforms being exclusively directed by the fuzzy resource manager and the attacking platforms being controlled by the human expert or operating autonomously under their own logic. This approach automates the data mining problem. The game automatically creates a database reflecting the domain expert's knowledge, it calls a data mining function, a genetic algorithm, for data mining of the database as required. The game allows easy evaluation of the information mined in the second step. The measure of effectiveness (MOE) for re-optimization is discussed. The mined information is extremely valuable as shown through demanding scenarios.

    13. The spatial ultimatum game.

      PubMed Central

      Page, K M; Nowak, M A; Sigmund, K

      2000-01-01

      In the ultimatum game, two players are asked to split a certain sum of money. The proposer has to make an offer. If the responder accepts the offer, the money will be shared accordingly. If the responder rejects the offer, both players receive nothing. The rational solution is for the proposer to offer the smallest possible share, and for the responder to accept it. Human players, in contrast, usually prefer fair splits. In this paper, we use evolutionary game theory to analyse the ultimatum game. We first show that in a non-spatial setting, natural selection chooses the unfair, rational solution. In a spatial setting, however, much fairer outcomes evolve. PMID:11413630

    14. Constructionist Gaming: Understanding the Benefits of Making Games for Learning

      PubMed Central

      Kafai, Yasmin B.; Burke, Quinn

      2015-01-01

      There has been considerable interest in examining the educational potential of playing video games. One crucial element, however, has traditionally been left out of these discussions—namely, children's learning through making their own games. In this article, we review and synthesize 55 studies from the last decade on making games and learning. We found that the majority of studies focused on teaching coding and academic content through game making, and that few studies explicitly examined the roles of collaboration and identity in the game making process. We argue that future discussions of serious gaming ought to be more inclusive of constructionist approaches to realize the full potential of serious gaming. Making games, we contend, not only more genuinely introduces children to a range of technical skills but also better connects them to each other, addressing the persistent issues of access and diversity present in traditional digital gaming cultures.

    15. Stochastic reinforcement benefits skill acquisition

      PubMed Central

      Dayan, Eran; Averbeck, Bruno B.; Richmond, Barry J.; Cohen, Leonardo G.

      2014-01-01

      Learning complex skills is driven by reinforcement, which facilitates both online within-session gains and retention of the acquired skills. Yet, in ecologically relevant situations, skills are often acquired when mapping between actions and rewarding outcomes is unknown to the learning agent, resulting in reinforcement schedules of a stochastic nature. Here we trained subjects on a visuomotor learning task, comparing reinforcement schedules with higher, lower, or no stochasticity. Training under higher levels of stochastic reinforcement benefited skill acquisition, enhancing both online gains and long-term retention. These findings indicate that the enhancing effects of reinforcement on skill acquisition depend on reinforcement schedules. PMID:24532838

    16. A stochastic multi-symplectic scheme for stochastic Maxwell equations with additive noise

      SciTech Connect

      Hong, Jialin; Zhang, Liying

      2014-07-01

      In this paper we investigate a stochastic multi-symplectic method for stochastic Maxwell equations with additive noise. Based on the stochastic version of variational principle, we find a way to obtain the stochastic multi-symplectic structure of three-dimensional (3-D) stochastic Maxwell equations with additive noise. We propose a stochastic multi-symplectic scheme and show that it preserves the stochastic multi-symplectic conservation law and the local and global stochastic energy dissipative properties, which the equations themselves possess. Numerical experiments are performed to verify the numerical behaviors of the stochastic multi-symplectic scheme.

    17. Second-Chance Signal Transduction Explains Cooperative Flagellar Switching

      PubMed Central

      Zot, Henry G.; Hasbun, Javier E.; Van Minh, Nguyen

      2012-01-01

      The reversal of flagellar motion (switching) results from the interaction between a switch complex of the flagellar rotor and a torque-generating stationary unit, or stator (motor unit). To explain the steeply cooperative ligand-induced switching, present models propose allosteric interactions between subunits of the rotor, but do not address the possibility of a reaction that stimulates a bidirectional motor unit to reverse direction of torque. During flagellar motion, the binding of a ligand-bound switch complex at the dwell site could excite a motor unit. The probability that another switch complex of the rotor, moving according to steady-state rotation, will reach the same dwell site before that motor unit returns to ground state will be determined by the independent decay rate of the excited-state motor unit. Here, we derive an analytical expression for the energy coupling between a switch complex and a motor unit of the stator complex of a flagellum, and demonstrate that this model accounts for the cooperative switching response without the need for allosteric interactions. The analytical result can be reproduced by simulation when (1) the motion of the rotor delivers a subsequent ligand-bound switch to the excited motor unit, thereby providing the excited motor unit with a second chance to remain excited, and (2) the outputs from multiple independent motor units are constrained to a single all-or-none event. In this proposed model, a motor unit and switch complex represent the components of a mathematically defined signal transduction mechanism in which energy coupling is driven by steady-state and is regulated by stochastic ligand binding. Mathematical derivation of the model shows the analytical function to be a general form of the Hill equation (Hill AV (1910) The possible effects of the aggregation of the molecules of haemoglobin on its dissociation curves. J Physiol 40: ivvii). PMID:22844429

    18. Optical Circuit Switched Protocol

      NASA Technical Reports Server (NTRS)

      Monacos, Steve P. (Inventor)

      2000-01-01

      The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

    19. The Atomic Dating Game.

      ERIC Educational Resources Information Center

      Cummo, Evelyn; Matthews, Catherine E.

      2002-01-01

      Presents an activity designed to provide students with opportunities to practice drawing atomic models and discover the logical pairings of whole families on the periodic table. Follows the format of a television game show. (DDR)

    20. On Stochastic Processes with Constant Valuation

      NASA Astrophysics Data System (ADS)

      Abbas, Ali E.

      2009-12-01

      In the probability literature, a martingale is often referred to as a fair game. A risk neutral decision maker would be indifferent to engaging in a martingale investment for any number of stages or not engaging into it at all if its expected value is equal to his current wealth. But a risk-averse decision maker would not accept a martingale pay-off in exchange for its expected value since his certain equivalent for uncertain deals is less than their mean. Therefore the traditional martingale sequences that are widely studied in probability and finance are not rational investments for risk averse decision makers. A risk seeking decision maker, on the other hand would welcome a martingale investment, since the certain equivalent is larger than the mean. We introduce a class of stochastic processes whose expected utility is constant and equal to the utility of the current wealth. We refer to such processes as risk-adjusted martingales. We show how to construct such processes for any continuous and strictly monotonic utility function.

    1. The variance of two game tree algorithms

      SciTech Connect

      Zhang, Yanjun

      1997-06-01

      This paper studies the variance of two game tree algorithms {alpha}-{beta} search and SCOUT, in the stochastic i.i.d. model. The problem of determining the variance of the classic {alpha}-{beta} search algorithm in the i.i.d. model has been long open. This paper resolves this problem partially. It is shown, by the martingale method, that the standard deviation of the weaker {alpha}-{beta} search without deep cutoffs is of the same order as the expected number of leaves evaluated. A nearly-optimal upper bound on the variance of the general {alpha}-{beta} search is obtained, and this upper bound yields an optimal bound if the current upper bound on the expected number of leaves evaluated by {alpha}-{beta} search can be improved. A thorough treatment of the two-pass SCOUT algorithm is presented. The variance of the SCOUT algorithm is determined.

    2. Quantum Games under Decoherence

      NASA Astrophysics Data System (ADS)

      Huang, Zhiming; Qiu, Daowen

      2016-02-01

      Quantum systems are easily influenced by ambient environments. Decoherence is generated by system interaction with external environment. In this paper, we analyse the effects of decoherence on quantum games with Eisert-Wilkens-Lewenstein (EWL) (Eisert et al., Phys. Rev. Lett. 83(15), 3077 1999) and Marinatto-Weber (MW) (Marinatto and Weber, Phys. Lett. A 272, 291 2000) schemes. Firstly, referring to the analytical approach that was introduced by Eisert et al. (Phys. Rev. Lett. 83(15), 3077 1999), we analyse the effects of decoherence on quantum Chicken game by considering different traditional noisy channels. We investigate the Nash equilibria and changes of payoff in specific two-parameter strategy set for maximally entangled initial states. We find that the Nash equilibria are different in different noisy channels. Since Unruh effect produces a decoherence-like effect and can be perceived as a quantum noise channel (Omkar et al., arXiv: 1408.1477v1), with the same two parameter strategy set, we investigate the influences of decoherence generated by the Unruh effect on three-player quantum Prisoners' Dilemma, the non-zero sum symmetric multiplayer quantum game both for unentangled and entangled initial states. We discuss the effect of the acceleration of noninertial frames on the the game's properties such as payoffs, symmetry, Nash equilibrium, Pareto optimal, dominant strategy, etc. Finally, we study the decoherent influences of correlated noise and Unruh effect on quantum Stackelberg duopoly for entangled and unentangled initial states with the depolarizing channel. Our investigations show that under the influence of correlated depolarizing channel and acceleration in noninertial frame, some critical points exist for an unentangled initial state at which firms get equal payoffs and the game becomes a follower advantage game. It is shown that the game is always a leader advantage game for a maximally entangled initial state and there appear some points at which the payoffs become zero.

    3. Multichoice minority game

      SciTech Connect

      Ein-Dor, Liat; Metzler, Richard; Kanter, Ido; Kinzel, Wolfgang

      2001-06-01

      The generalization of the problem of adaptive competition, known as the minority game, to the case of K possible choices for each player, is addressed, and applied to a system of interacting perceptrons with input and output units of a type of K-state Potts spins. An optimal solution of this minority game, as well as the dynamic evolution of the adaptive strategies of the players, are solved analytically for a general K and compared with numerical simulations.

    4. Serious games for Geophysics

      NASA Astrophysics Data System (ADS)

      Lombardo, Valerio; Rubbia, Giuliana

      2015-04-01

      Childhood stage is indispensable in the education of human beings and especially critical to arise scientific interest in children. We discuss the participatory design of a didactic videogame, i.e. a "serious" game to teach geophysics and Earth sciences to high and low-school students. Geophysics is the application of the laws and techniques of physics to uncover knowledge about the earth's dynamic processes and subsurface structure. It explores phenomena such as earthquakes, volcanoes, tsunamis to improve our understanding of the earth's physical processes and our ability to predict reoccurrences. Effective mitigation of risks from catastrophic geologic hazards requires knowledge and understanding of local geology and geologic processes. Scientific outreach can be defined as discourse activity, whose main objective is to communicate some knowledge previously produced in scientific contexts to a non-expert massive audience. One of the difficulties science educators need to overcome is to explain specific concepts from a given discipline in a language simple and understandable for their audience. Digital games today play a large role in young people's lives. Games are directly connected to the life of today's adolescents. Therefore, digital games should be included and broached as a subject in the classroom. The ardor and enthusiasm that digital games evoke in teenagers has indeed brought many researchers, school leaders and teachers to the question "how video games" can be used to engage young people and support their learning inside the classroom. Additionally, studies have shown that digital games can enhance various skills such as the ability to concentrate, stamina, tactical aptness, anticipatory thinking, orientation in virtual spaces, and deductive reasoning. Thus, videogames become an effective didactic mechanism and should have a place in the classroom. The project aims to explore the potentials of entertainment technologies in educational processes; contribute to innovative pedagogies for scientific learning; create a scientific feedback-loop with students and teachers; implement a multi-level video game for scientific outreach.

    5. Getting into the Game

      ERIC Educational Resources Information Center

      Galuszka, Peter

      2009-01-01

      Malcolm Perdue faces a dilemma as challenging as the computer games he loves to play. The 19-year-old student at Atlanta Metropolitan College wants to learn how to become a game designer. Not only would doing so be a lot of fun, designers can make $80,000 a year early in their careers. But his school has limited options in the field. Nearby

    6. Getting into the Game

      ERIC Educational Resources Information Center

      Galuszka, Peter

      2009-01-01

      Malcolm Perdue faces a dilemma as challenging as the computer games he loves to play. The 19-year-old student at Atlanta Metropolitan College wants to learn how to become a game designer. Not only would doing so be a lot of fun, designers can make $80,000 a year early in their careers. But his school has limited options in the field. Nearby…

    7. Optimality and adaptation of phenotypically switching cells in fluctuating environments

      NASA Astrophysics Data System (ADS)

      Belete, Merzu Kebede; Balázsi, Gábor

      2015-12-01

      Stochastic switching between alternative phenotypic states is a common cellular survival strategy during unforeseen environmental fluctuations. Cells can switch between different subpopulations that proliferate at different rates in different environments. Optimal population growth is typically assumed to occur when phenotypic switching rates match environmental switching rates. However, it is not well understood how this optimum behaves as a function of the growth rates of phenotypically different cells. In this study, we use mathematical and computational models to test how the actual parameters associated with optimal population growth differ from those assumed to be optimal. We find that the predicted optimum is practically always valid if the environmental durations are long. However, the regime of validity narrows as environmental durations shorten, especially if subpopulation growth rate differences differ from each other (are asymmetric) in two environments. Furthermore, we study the fate of mutants with switching rates previously predicted to be optimal. We find that mutants which match their phenotypic switching rates with the environmental ones can only sweep the population if the assumed optimum is valid, but not otherwise.

    8. Solid state switch

      DOEpatents

      Merritt, B.T.; Dreifuerst, G.R.

      1994-07-19

      A solid state switch, with reverse conducting thyristors, is designed to operate at 20 kV hold-off voltage, 1,500 A peak, 1.0 [mu]s pulsewidth, and 4,500 pps, to replace thyratrons. The solid state switch is more reliable, more economical, and more easily repaired. The switch includes a stack of circuit card assemblies, a magnetic assist and a trigger chassis. Each circuit card assembly contains a reverse conducting thyristor, a resistor capacitor network, and triggering circuitry. 6 figs.

    9. Photoconductive switch package

      DOEpatents

      Ca[rasp, George J

      2013-10-22

      A photoconductive switch is formed of a substrate that has a central portion of SiC or other photoconductive material and an outer portion of cvd-diamond or other suitable material surrounding the central portion. Conducting electrodes are formed on opposed sides of the substrate, with the electrodes extending beyond the central portion and the edges of the electrodes lying over the outer portion. Thus any high electric fields produced at the edges of the electrodes lie outside of and do not affect the central portion, which is the active switching element. Light is transmitted through the outer portion to the central portion to actuate the switch.

    10. Photoconductive switch package

      DOEpatents

      Caporaso, George J.

      2015-10-27

      A photoconductive switch is formed of a substrate that has a central portion of SiC or other photoconductive material and an outer portion of cvd-diamond or other suitable material surrounding the central portion. Conducting electrodes are formed on opposed sides of the substrate, with the electrodes extending beyond the central portion and the edges of the electrodes lying over the outer portion. Thus any high electric fields produced at the edges of the electrodes lie outside of and do not affect the central portion, which is the active switching element. Light is transmitted through the outer portion to the central portion to actuate the switch.

    11. Photoconductive switch package

      DOEpatents

      Caporaso, George J

      2015-11-05

      A photoconductive switch is formed of a substrate that has a central portion of SiC or other photoconductive material and an outer portion of cvd-diamond or other suitable material surrounding the central portion. Conducting electrodes are formed on opposed sides of the substrate, with the electrodes extending beyond the central portion and the edges of the electrodes lying over the outer portion. Thus any high electric fields produced at the edges of the electrodes lie outside of and do not affect the central portion, which is the active switching element. Light is transmitted through the outer portion to the central portion to actuate the switch.

    12. Plastic complementary microelectromechanical switches

      NASA Astrophysics Data System (ADS)

      Yokota, Tomoyuki; Nakano, Shintaro; Sekitani, Tsuyoshi; Someya, Takao

      2008-07-01

      We have fabricated plastic complementary microelectromechanical switches by using ink-jet printing technologies. Two vertically stacked regular plastic microelectromechanical switches that are complementary to each other realize the function of an inverter. While rectangular voltage waveforms were periodically applied to the control electrodes in the air, the delay times and durability were examined systematically. The frequency response was 50 Hz for an operation voltage of 60 V. When the number of periodic cycles exceeded 106, the changes in the on resistance of the top and bottom switches were 9% and 43%, respectively.

    13. Electromechanical magnetization switching

      SciTech Connect

      Chudnovsky, Eugene M.; Jaafar, Reem

      2015-03-14

      We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

    14. Utilizing Video Games

      NASA Astrophysics Data System (ADS)

      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.

    15. Equilibrium games in networks

      NASA Astrophysics Data System (ADS)

      Li, Angsheng; Zhang, Xiaohui; Pan, Yicheng; Peng, Pan

      2014-12-01

      It seems a universal phenomenon of networks that the attacks on a small number of nodes by an adversary player Alice may generate a global cascading failure of the networks. It has been shown (Li et al., 2013) that classic scale-free networks (Barabsi and Albert, 1999, Barabsi, 2009) are insecure against attacks of as small as O(logn) many nodes. This poses a natural and fundamental question: Can we introduce a second player Bob to prevent Alice from global cascading failure of the networks? We proposed a game in networks. We say that a network has an equilibrium game if the second player Bob has a strategy to balance the cascading influence of attacks by the adversary player Alice. It was shown that networks of the preferential attachment model (Barabsi and Albert, 1999) fail to have equilibrium games, that random graphs of the Erds-Rnyi model (Erds and Rnyi, 1959, Erds and Rnyi, 1960) have, for which randomness is the mechanism, and that homophyly networks (Li et al., 2013) have equilibrium games, for which homophyly and preferential attachment are the underlying mechanisms. We found that some real networks have equilibrium games, but most real networks fail to have. We anticipate that our results lead to an interesting new direction of network theory, that is, equilibrium games in networks.

    16. Internet gaming addiction: current perspectives

      PubMed Central

      Kuss, Daria J

      2013-01-01

      In the 2000s, online games became popular, while studies of Internet gaming addiction emerged, outlining the negative consequences of excessive gaming, its prevalence, and associated risk factors. The establishment of specialized treatment centers in South-East Asia, the US, and Europe reflects the growing need for professional help. It is argued that only by understanding the appeal of Internet gaming, its context, and neurobiologic correlates can the phenomenon of Internet gaming addiction be understood comprehensively. The aim of this review is to provide an insight into current perspectives on Internet gaming addiction using a holistic approach, taking into consideration the mass appeal of online games, the context of Internet gaming addiction, and associated neuroimaging findings, as well as the current diagnostic framework adopted by the American Psychiatric Association. The cited research indicates that the individual’s context is a significant factor that marks the dividing line between excessive gaming and gaming addiction, and the game context can gain particular importance for players, depending on their life situation and gaming preferences. Moreover, the cultural context is significant because it embeds the gamer in a community with shared beliefs and practices, endowing their gaming with particular meaning. The cited neuroimaging studies indicate that Internet gaming addiction shares similarities with other addictions, including substance dependence, at the molecular, neurocircuitry, and behavioral levels. The findings provide support for the current perspective of understanding Internet gaming addiction from a disease framework. The benefits of an Internet gaming addiction diagnosis include reliability across research, destigmatization of individuals, development of efficacious treatments, and the creation of an incentive for public health care and insurance providers. The holistic approach adopted here not only highlights empirical research that evidences neurobiologic correlates of Internet gaming addiction and the establishment of a preliminary diagnosis, but also emphasizes the necessity of an indepth understanding of the meaning, context, and practices associated with gaming. PMID:24255603

    17. ID201202961, DOE S-124,539, Information Security Analysis Using Game Theory and Simulation

      SciTech Connect

      Abercrombie, Robert K; Schlicher, Bob G

      2012-01-01

      Information security analysis can be performed using game theory implemented in dynamic simulations of Agent Based Models (ABMs). Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. Our approach addresses imperfect information and scalability that allows us to also address previous limitations of current stochastic game models. Such models only consider perfect information assuming that the defender is always able to detect attacks; assuming that the state transition probabilities are fixed before the game assuming that the players actions are always synchronous; and that most models are not scalable with the size and complexity of systems under consideration. Our use of ABMs yields results of selected experiments that demonstrate our proposed approach and provides a quantitative measure for realistic information systems and their related security scenarios.

    18. Electrical Breakdown Physics in Photoconductive Semiconductor Switches (PCSS).

      SciTech Connect

      Mar, Alan; Zutavern, Fred J.; Vawter, Gregory A.; Hjalmarson, Harold P.; Gallegos, Richard Joseph; Bigman, Verle Howard

      2016-01-01

      Advanced switching devices with long lifetime will be critical components for Linear Transformer Drivers (LTDs) in next-generation accelerators. LTD designs employ high switch counts. With current gas switch technology at %7E10e3 shot life, a potential game-changer would be the development of a reliable low-impedance (%3C35nh) optically-triggered compact solid-state switch capable of switching 200kV and 50kA with 10e5 shotlife or better. Other applications of this technology, are pulse shaping programmable systems for dynamic material studies (Z-next, Genesis), efficient pulsed power systems for biofuel feedstock, short pulse (10 ns) accelerator designs for the Defense Threat Reduction Agency (DTRA), and sprytron replacements in NW firing sets. This LDRD project has succeeded in developing new optically-triggered photoconductive semiconductor switch (PCSS) designs that show great promise for scaling to modules capable of 200kV (DC) and 5kA current that can be stacked in parallel to achieve 100's of kA with 10e5 shot lifetime. . Executive Summary Advanced switching devices with long lifetime will be critical components for Linear Transformer Drivers (LTDs) in next-generation accelerators. LTD designs employ high switch counts. With current gas switch technology at %7E10e3 shot life, a potential game-changer would be the development of a reliable low-impedance (%3C35nh) optically-triggered compact solid-state switch capable of switching 200kV and 50kA with 10e5 shotlife or better. Other applications of this technology, are pulse shaping programmable systems for dynamic material studies (Z-next, Genesis), efficient pulsed power systems for biofuel feedstock, short pulse (10 ns) accelerator designs for the Defense Threat Reduction Agency (DTRA), and sprytron replacements in NW firing sets. This LDRD project has succeeded in developing new optically-triggered photoconductive semiconductor switch (PCSS) designs that show great promise for scaling to modules capable of 200kV (DC) and 5kA current that can be stacked in parallel to achieve 100's of kA with 10e5 shot lifetime. The new vertical switch design configuration generates parallel filaments in the bulk GaAs (as opposed to just beneath the surface as in previous designs) to achieve breakdown fields close to the maximum for the bulk GaAs while operating in air, and with 2-D scalability of the number of current-sharing filaments. This design also may be highly compatible with 2-D VCSEL arrays for optical triggering. The demonstration of this design in this LDRD utilized standard thickness wafers to trigger 0.4kA at 35kV/cm (limited by 0.6mm wafer thickness), tested to 1e5 shots with no detectable degradation of switch performance. Higher fields, total current, and switching voltages would be achievable with thicker GaAs wafers. Another important application pursued in this LDRD is the use of PCSS for trigger generator applications. Conventional in-plane PCSS have achieved triggering of a 100kV sparkgap (Kinetech-type) switch of the type similar to switches being considered for accelerator upgrades. The trigger is also being developed for pulsed power for HPM applications that require miniaturization and robust performance in noisy compact environments. This has spawned new programs for developing this technology, including an STTR for VCSEL trigger laser integration, also pursuing other follow-on applications.

    19. Stochastic superparameterization in quasigeostrophic turbulence

      SciTech Connect

      Grooms, Ian; Majda, Andrew J.

      2014-08-15

      In this article we expand and develop the authors' recent proposed methodology for efficient stochastic superparameterization algorithms for geophysical turbulence. Geophysical turbulence is characterized by significant intermittent cascades of energy from the unresolved to the resolved scales resulting in complex patterns of waves, jets, and vortices. Conventional superparameterization simulates large scale dynamics on a coarse grid in a physical domain, and couples these dynamics to high-resolution simulations on periodic domains embedded in the coarse grid. Stochastic superparameterization replaces the nonlinear, deterministic eddy equations on periodic embedded domains by quasilinear stochastic approximations on formally infinite embedded domains. The result is a seamless algorithm which never uses a small scale grid and is far cheaper than conventional SP, but with significant success in difficult test problems. Various design choices in the algorithm are investigated in detail here, including decoupling the timescale of evolution on the embedded domains from the length of the time step used on the coarse grid, and sensitivity to certain assumed properties of the eddies (e.g. the shape of the assumed eddy energy spectrum). We present four closures based on stochastic superparameterization which elucidate the properties of the underlying framework: a null hypothesis stochastic closure that uncouples the eddies from the mean, a stochastic closure with nonlinearly coupled eddies and mean, a nonlinear deterministic closure, and a stochastic closure based on energy conservation. The different algorithms are compared and contrasted on a stringent test suite for quasigeostrophic turbulence involving two-layer dynamics on a ?-plane forced by an imposed background shear. The success of the algorithms developed here suggests that they may be fruitfully applied to more realistic situations. They are expected to be particularly useful in providing accurate and efficient stochastic parameterizations for use in ensemble-based state estimation and prediction.

    20. Stochastic roots of growth phenomena

      NASA Astrophysics Data System (ADS)

      De Lauro, E.; De Martino, S.; De Siena, S.; Giorno, V.

      2014-05-01

      We show that the Gompertz equation describes the evolution in time of the median of a geometric stochastic process. Therefore, we induce that the process itself generates the growth. This result allows us further to exploit a stochastic variational principle to take account of self-regulation of growth through feedback of relative density variations. The conceptually well defined framework so introduced shows its usefulness by suggesting a form of control of growth by exploiting external actions.

    1. Learning process in public goods games

      NASA Astrophysics Data System (ADS)

      Amado, Andr; Huang, Weini; Campos, Paulo R. A.; Ferreira, Fernando Fagundes

      2015-07-01

      We propose an individual-based model to describe the effects of memory and learning in the evolution of cooperation in a public goods game (PGG) in a well-mixed population. Individuals are endowed with a set of strategies, and in every round of the game they use one strategy out of this set based on their memory and learning process. The payoff of a player using a given strategy depends on the public goods enhancement factor r and the collective action of all players. We investigate the distribution of used strategies as well as the distribution of information patterns. The outcome depends on the learning process, which can be dynamic or static. In the dynamic learning process, the players can switch their strategies along the whole game, and use the strategy providing the highest payoff at current time step. In the static learning process, there is a training period where the players randomly explore different strategies out of their strategy sets. In the rest of the game, players only use the strategy providing the highest payoff during the training period. In the dynamic learning process, we observe a transition from a non-cooperative regime to a regime where the level of cooperation reaches about 50 %. As in the standard PGG, in the static learning process there is a transition from the non-cooperative regime to a regime where the level of cooperation can be higher than 50% at r = N. In both learning processes the transition becomes smoother as the memory size of individuals increases, which means that the lack of information is a key ingredient causing the defection.

    2. Plasmonic enhanced ultrafast switch.

      SciTech Connect

      Subramania,Ganapathi Subramanian; Reno, John Louis; Passmore, Brandon Scott; Harris, Tom.; Shaner, Eric Arthur; Barrick, Todd A.

      2009-09-01

      Ultrafast electronic switches fabricated from defective material have been used for several decades in order to produce picosecond electrical transients and TeraHertz radiation. Due to the ultrashort recombination time in the photoconductor materials used, these switches are inefficient and are ultimately limited by the amount of optical power that can be applied to the switch before self-destruction. The goal of this work is to create ultrafast (sub-picosecond response) photoconductive switches on GaAs that are enhanced through plasmonic coupling structures. Here, the plasmonic coupler primarily plays the role of being a radiation condenser which will cause carriers to be generated adjacent to metallic electrodes where they can more efficiently be collected.

    3. An optical switch

      DOEpatents

      Christophorou, L.G.; Hunter, S.R.

      1987-04-30

      The invention is a gas mixture for a diffuse discharge switch having an electron attaching gas wherein electron attachment is brought about by indirect excitation of molecules to long live states by exposure to laser light. 3 figs.

    4. Miniature Intermittent Contact Switch

      NASA Technical Reports Server (NTRS)

      Sword, Antony

      1972-01-01

      This tech brief concerns work to provide a shock-resistant switch capable of being actuated by forces of varying magnitude and direction, primarily for use as a sensor on remote control (tele-operator) and prosthetic devices.

    5. Solar array switching unit

      NASA Technical Reports Server (NTRS)

      Craig, Jr., Calvin L. (Inventor)

      2000-01-01

      A solar array switching (SASU) unit (22) according to the present invention includes a control system (24), a solar cell array (26) and switch circuits (28). The SASU unit (22) is associated with a power card (30) for receiving an output from the array (26). The array (26) has a number (0.5Y) of rows (38) each of which includes a pair of cell strings (42) separated by one of the switch circuits (28). Each of the strings (42) includes a number (X) of cells in electrical series. The SASU (22) switches the array (26) between a short string configuration where the array (26) effectively includes Y strings of X length, and a long string configuration where the array (26) effectively includes 0.5Y strings of 2X length. The SASU (22) thereby facilitates the use of solar power for space missions where solar intensity, operating temperature or other factors vary significantly.

    6. A numerical scheme for optimal transition paths of stochastic chemical kinetic systems

      NASA Astrophysics Data System (ADS)

      Liu, Di

      2008-10-01

      We present a new framework for finding the optimal transition paths of metastable stochastic chemical kinetic systems with large system size. The optimal transition paths are identified to be the most probable paths according to the Large Deviation Theory of stochastic processes. Dynamical equations for the optimal transition paths are derived using the variational principle. A modified Minimum Action Method (MAM) is proposed as a numerical scheme to solve the optimal transition paths. Applications to Gene Regulatory Networks such as the toggle switch model and the Lactose Operon Model in Escherichia coli are presented as numerical examples.

    7. Stochastic pooling networks

      NASA Astrophysics Data System (ADS)

      McDonnell, Mark D.; Amblard, Pierre-Olivier; Stocks, Nigel G.

      2009-01-01

      We introduce and define the concept of a stochastic pooling network (SPN), as a model for sensor systems where redundancy and two forms of 'noise'lossy compression and randomnessinteract in surprising ways. Our approach to analysing SPNs is information theoretic. We define an SPN as a network with multiple nodes that each produce noisy and compressed measurements of the same information. An SPN must combine all these measurements into a single further compressed network output, in a way dictated solely by naturally occurring physical propertiesi.e. poolingand yet cause no (or negligible) reduction in mutual information. This means that SPNs exhibit redundancy reduction as an emergent property of pooling. The SPN concept is applicable to examples in biological neural coding, nanoelectronics, distributed sensor networks, digital beamforming arrays, image processing, multiaccess communication networks and social networks. In most cases the randomness is assumed to be unavoidably present rather than deliberately introduced. We illustrate the central properties of SPNs for several case studies, where pooling occurs by summation, including nodes that are noisy scalar quantizers, and nodes with conditionally Poisson statistics. Other emergent properties of SPNs and some unsolved problems are also briefly discussed.

    8. Delayed stochastic control

      NASA Astrophysics Data System (ADS)

      Hosaka, Tadaaki; Ohira, Toru; Lucian, Christian; Milton, John

      2005-03-01

      Time-delayed feedback control becomes problematic in situations in which the time constant of the system is fast compared to the feedback reaction time. In particular, when perturbations are unpredictable, traditional feedback or feed-forward control schemes can be insufficient. Nonethless a human can balance a stick at their fingertip in the presence of fluctuations that occur on time scales shorter than their neural reaction times. Here we study a simple model of a repulsive delayed random walk and demonstrate that the interplay between noise and delay can transiently stabilize an unstable fixed-point. This observation leads to the concept of ``delayed stochastic control,'' i.e. stabilization of tasks, such as stick balancing at the fingertip, by optimally tuning the noise level with respect to the feedback delay time. References:(1)J.L.Cabrera and J.G.Milton, PRL 89 158702 (2002);(2) T. Ohira and J.G.Milton, PRE 52 3277 (1995);(3)T.Hosaka, T.Ohira, C.Lucian, J.L.Cabrera, and J.G.Milton, Prog. Theor. Phys. (to appear).

    9. Cygnus Water Switch Jitter

      SciTech Connect

      Charles V. Mitton, George D. Corrow, Mark D. Hansen, David J. Henderson, et al.

      2008-03-01

      The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources - Cygnus 1 and Cygnus 2. Each source has the following x-ray output: 1-mm diameter spot size, 4 rad at 1 m, 50-ns Full Width Half Max. The diode pulse has the following electrical specifications: 2.25 MV, 60 kA, 60 ns. This Radiographic Facility is located in an underground tunnel test area at the Nevada Test Site (NTS). The sources were developed to produce high-resolution images on subcritical tests which are performed at NTS. Subcritical tests are single-shot, high-value events. For this application, it is desirable to maintain a high level of reproducibility in source output. The major components of the Cygnus machines are: Marx generator, water-filled pulse–forming line (PFL), water-filled coaxial transmission line, three-cell inductive voltage adder, and rod-pinch diode. A primary source of fluctuation in Cygnus shot-to-shot performance is jitter in breakdown of the main PFL switch, which is a “self-break” switch. The PFL switch breakdown time determines the peak PFL charging voltage, which ultimately affects the diode pulse. Therefore, PFL switch jitter contributes to shot-to-shot variation in source endpoint energy and dose. In this paper we will present PFL switch jitter analysis for both Cygnus machines and give the correlation with diode performance. For this analysis the PFL switch on each machine was maintained at a single gap setting which has been used for the majority of shots at NTS. In addition to this analysis, PFL switch performance for different switch gap settings taken recently will be examined. Lastly, implications of source jitter for radiographic diagnosis of subcritical shots will be discussed.

    10. Optical shutter switching matrix

      NASA Technical Reports Server (NTRS)

      Grove, Charles H.

      1991-01-01

      The interface switching systems are discussed which are related to those used in the Space Shuttle ground control system, transmission systems, communications systems, and airborne radar electronic countermeasure systems. The main goal is to identify a need that exists throughout the comprehensive information processing and communications disciplines supporting the Space Shuttle and Space Station programs, and introduce one viable approach to satisfy that need. The proposed device, described in NASA patent entitled 'Optical Shutter Switch Matrix', is discussed.

    11. Application and Evaluation of Analytic Gaming

      SciTech Connect

      Riensche, Roderick M.; Martucci, Louis M.; Scholtz, Jean; Whiting, Mark A.

      2009-08-31

      We describe an "analytic gaming" framework and methodology, and introduce formal methods for evaluation of the analytic gaming process. This process involves conception, development, and playing of games that are informed by predictive models and driven by players. Evaluation of analytic gaming examines both the process of game development and the results of game play exercises.

    12. Meta-Games in Information Work

      ERIC Educational Resources Information Center

      Huvila, Isto

      2013-01-01

      Introduction: Meta-games and meta-gaming refer to various second-order conceptions of games and gaming. The present article discusses the applicability of the notions of meta-game and meta-gaming in understanding the patterns of how people use, misuse, work and work-around information and information infrastructures. Method: Twenty-two qualitative…

    13. Stochastic signalling in excitable ion channel clusters

      NASA Astrophysics Data System (ADS)

      Schmid, Gerhard

      2005-03-01

      The electric properties of axonal cell membranes are predominantly determined by the dynamics of the voltage-dependent gating of potassium and sodium ion channels. The inherent stochastic dynamics of the gating process generates the so-called channel noise. These fluctuations of the number of open ion channels initiate spontaneous excitations. By use of a stochastic generalization of the Hodgkin-Huxley model we investigate the dependency of the spike production on the number of ion channels within a cluster. There exist an optimal cluster size for which solely the internal noise causes a most regular spontaneous generation of action potentials -- the effect of intrinsic coherence resonance -- and an optimal system size induced Stochastic Resonance in presence of external driving [1,2]. In addition to the variation of the size of ion channel clusters, the living organisms may adopt the densities of different ion channels in order to regulate the spontaneous spiking activity. We vary the densities, i.e. the number of the specific ion channels for a given membrane patch size by poisoning the potassium, or the sodium ion channels yielding either an increase or decrease of the regularity of the spiking dynamics [3].We also investigate the influence of the gating charge on spontaneous spiking: the ion channels contribute to the membrane capacity, since the switching of the channel gates between an open and a closed configuration is always connected with charge movement within the cell membrane. Especially, for the case of relatively large densities of ion channels (such as in nodes of Ranvier), this may play a crucial role for nerve excitation. Surprisingly, the gating charge do not dramatically change the excitation behavior. This even holds true even for extremely dense ion channel assemblies; instead the membrane capacity at rest exhibits a bell-shaped dependence on the ion channel density. [1] G. Schmid, I. Goychuk and P. H'nggi, Europhys. Lett 56, 22 (2001).[2] G. Schmid, I. Goychuk, P. H'nggi, S. Zeng, and P. Jung, Fluct. Noise Lett. 4, L33 (2004).[3] G. Schmid, I. Goychuk, and P. H'nggi, Physical Biology 1, 61 (2004).

    14. Games Children Play: How Games and Sport Help Children Develop.

      ERIC Educational Resources Information Center

      Brooking-Payne, Kim

      This book presents games for children, teenagers, and adults, explaining how each game can help children develop in a holistic way. It begins by discussing tips for teaching games, how to deal with children who break the rules, and what type of equipment to use. The book provides help on how to approach play within each of the different age

    15. Constructionist Gaming: Understanding the Benefits of Making Games for Learning

      ERIC Educational Resources Information Center

      Kafai, Yasmin B.; Burke, Quinn

      2015-01-01

      There has been considerable interest in examining the educational potential of playing video games. One crucial element, however, has traditionally been left out of these discussions--namely, children's learning through making their own games. In this article, we review and synthesize 55 studies from the last decade on making games and learning.…

    16. Gaming Personality and Game Dynamics in Online Discussion Instructions

      ERIC Educational Resources Information Center

      Tu, Chih-Hsiung; Yen, Cherng-Jyh; Sujo-Montes, Laura; Roberts, Gayle A.

      2015-01-01

      Gamification is the use of game mechanics to drive game-like engagements and actions. It applies game mechanics, dynamics and frameworks to promote desired learning behaviours. Positive and effective gamification could enhance learning and engage learners in more social and context-rich decision-making for problem-solving in learning tasks.…

    17. Games, Gaming, and Gamification: Some Aspects of Motivation

      ERIC Educational Resources Information Center

      Hanson-Smith, Elizabeth

      2016-01-01

      Unsupported claims have been made for the use of games in education and the gamification (game-like aspects, such as scores and point goals) of various learning elements. This brief article examines what may be the motivational basis of gaming and how it can affect students' behavior and ultimate success.

    18. Mapping Learning and Game Mechanics for Serious Games Analysis

      ERIC Educational Resources Information Center

      Arnab, Sylvester; Lim, Theodore; Carvalho, Maira B.; Bellotti, Francesco; de Freitas, Sara; Louchart, Sandy; Suttie, Neil; Berta, Riccardo; De Gloria, Alessandro

      2015-01-01

      Although there is a consensus on the instructional potential of Serious Games (SGs), there is still a lack of methodologies and tools not only for design but also to support analysis and assessment. Filling this gap is one of the main aims of the Games and Learning Alliance (http://www.galanoe.eu) European Network of Excellence on Serious Games,…

    19. Digital Game-Based Learning: Towards an Experiential Gaming Model

      ERIC Educational Resources Information Center

      Kiili, Kristian

      2005-01-01

      Online games satisfy the basic requirements of learning environments and can provide engaging learning experiences for students. However, a model that successfully integrates educational theory and game design aspects do not exist. Thus, in this paper an experiential gaming model that is based on experiential learning theory, flow theory and game…

    20. Gaming Personality and Game Dynamics in Online Discussion Instructions

      ERIC Educational Resources Information Center

      Tu, Chih-Hsiung; Yen, Cherng-Jyh; Sujo-Montes, Laura; Roberts, Gayle A.

      2015-01-01

      Gamification is the use of game mechanics to drive game-like engagements and actions. It applies game mechanics, dynamics and frameworks to promote desired learning behaviours. Positive and effective gamification could enhance learning and engage learners in more social and context-rich decision-making for problem-solving in learning tasks.

    1. Constructionist Gaming: Understanding the Benefits of Making Games for Learning

      ERIC Educational Resources Information Center

      Kafai, Yasmin B.; Burke, Quinn

      2015-01-01

      There has been considerable interest in examining the educational potential of playing video games. One crucial element, however, has traditionally been left out of these discussions--namely, children's learning through making their own games. In this article, we review and synthesize 55 studies from the last decade on making games and learning.

    2. Computer Games Are Fun? On Professional Games and Players' Motivations

      ERIC Educational Resources Information Center

      Eglesz, Denes; Fekete, Istvan; Kiss, Orhidea Edith; Izso, Lajos

      2005-01-01

      As computer games are becoming more widespread, there is a tendency for young people to spend a growing amount of time playing games. The first part of this paper will deal with various types of computer games and their characteristic features. In the second part we show the results of our recent surveys. We examined the motivations of young

    3. ALTEC Learning Games: Successful Integration of Learning and Gaming

      ERIC Educational Resources Information Center

      Bacon, Melanie A.; Ault, Marilyn M.

      2009-01-01

      Of the 53 million K-12 students in the United States, 93%, or 51 million, of them play video games (Etuk, 2008). ALTEC Learning Games utilize the excitement of video games to engage students and provide teachers authentic online resources that reinforce skills in math and language arts. Our recent work was partially supported by a partnership with…

    4. Mapping Learning and Game Mechanics for Serious Games Analysis

      ERIC Educational Resources Information Center

      Arnab, Sylvester; Lim, Theodore; Carvalho, Maira B.; Bellotti, Francesco; de Freitas, Sara; Louchart, Sandy; Suttie, Neil; Berta, Riccardo; De Gloria, Alessandro

      2015-01-01

      Although there is a consensus on the instructional potential of Serious Games (SGs), there is still a lack of methodologies and tools not only for design but also to support analysis and assessment. Filling this gap is one of the main aims of the Games and Learning Alliance (http://www.galanoe.eu) European Network of Excellence on Serious Games,

    5. Low inductance gas switching.

      SciTech Connect

      Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

      2007-10-01

      The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and electrode diameter were conducted.

    6. 77 FR 76514 - Indian Gaming

      Federal Register 2010, 2011, 2012, 2013, 2014

      2012-12-28

      ... Gaming Machines from 76 to 816, and authorizes the operation of additional types of games including live poker and simulcast racing. The term of the Compact runs for 10 years from the date of this notice....

    7. Nuclear Power Plant Simulation Game.

      ERIC Educational Resources Information Center

      Weiss, Fran

      1979-01-01

      Presents a nuclear power plant simulation game which is designed to involve a class of 30 junior or senior high school students. Scientific, ecological, and social issues covered in the game are also presented. (HM)

    8. Question Games for Social Studies.

      ERIC Educational Resources Information Center

      Turner, Thomas N.

      1981-01-01

      Suggests using games to teach students how to ask effective questions. Games include "I've Got a Secret,""What's My Career,""To Tell the Truth,""Jeopardy,""Stump the Teacher,""Ten Q," and "Question Circle." (KC)

    9. Fractal Patterns and Chaos Games

      ERIC Educational Resources Information Center

      Devaney, Robert L.

      2004-01-01

      Teachers incorporate the chaos game and the concept of a fractal into various areas of the algebra and geometry curriculum. The chaos game approach to fractals provides teachers with an opportunity to help students comprehend the geometry of affine transformations.

    10. 78 FR 17428 - Indian Gaming

      Federal Register 2010, 2011, 2012, 2013, 2014

      2013-03-21

      ... III Tribal- State Gaming Compact between the Pyramid Lake Paiute Tribe and the State of Nevada... engaging in Class III gaming activities on Indian lands. On January 11, 2013, the Pyramid Lake Paiute...

    11. A radiation hard vacuum switch

      DOEpatents

      Boettcher, G.E.

      1988-07-19

      A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

    12. Energy losses in switches

      SciTech Connect

      Martin, T.H.; Seamen, J.F.; Jobe, D.O.

      1993-07-01

      The authors experiments show energy losses between 2 and 10 times that of the resistive time predictions. The experiments used hydrogen, helium, air, nitrogen, SF{sub 6} polyethylene, and water for the switching dielectric. Previously underestimated switch losses have caused over predicting the accelerator outputs. Accurate estimation of these losses is now necessary for new high-efficiency pulsed power devices where the switching losses constitute the major portion of the total energy loss. They found that the switch energy losses scale as (V{sub peak}I{sub peak}){sup 1.1846}. When using this scaling, the energy losses in any of the tested dielectrics are almost the same. This relationship is valid for several orders of magnitude and suggested a theoretical basis for these results. Currents up to .65 MA, with voltages to 3 MV were applied to various gaps during these experiments. The authors data and the developed theory indicates that the switch power loss continues for a much longer time than the resistive time, with peak power loss generally occurring at peak current in a ranging discharge instead of the early current time. All of the experiments were circuit code modeled after developing a new switch loss version based on the theory. The circuit code predicts switch energy loss and peak currents as a function of time. During analysis of the data they noticed slight constant offsets between the theory and data that depended on the dielectric. They modified the plasma conductivity for each tested dielectric to lessen this offset.

    13. Enhancing Cognition with Video Games: A Multiple Game Training Study

      PubMed Central

      Oei, Adam C.; Patterson, Michael D.

      2013-01-01

      Background Previous evidence points to a causal link between playing action video games and enhanced cognition and perception. However, benefits of playing other video games are under-investigated. We examined whether playing non-action games also improves cognition. Hence, we compared transfer effects of an action and other non-action types that required different cognitive demands. Methodology/Principal Findings We instructed 5 groups of non-gamer participants to play one game each on a mobile device (iPhone/iPod Touch) for one hour a day/five days a week over four weeks (20 hours). Games included action, spatial memory, match-3, hidden- object, and an agent-based life simulation. Participants performed four behavioral tasks before and after video game training to assess for transfer effects. Tasks included an attentional blink task, a spatial memory and visual search dual task, a visual filter memory task to assess for multiple object tracking and cognitive control, as well as a complex verbal span task. Action game playing eliminated attentional blink and improved cognitive control and multiple-object tracking. Match-3, spatial memory and hidden object games improved visual search performance while the latter two also improved spatial working memory. Complex verbal span improved after match-3 and action game training. Conclusion/Significance Cognitive improvements were not limited to action game training alone and different games enhanced different aspects of cognition. We conclude that training specific cognitive abilities frequently in a video game improves performance in tasks that share common underlying demands. Overall, these results suggest that many video game-related cognitive improvements may not be due to training of general broad cognitive systems such as executive attentional control, but instead due to frequent utilization of specific cognitive processes during game play. Thus, many video game training related improvements to cognition may be attributed to near-transfer effects. PMID:23516504

    14. Stochastic dynamics and mechanosensitivity of myosin II minifilaments

      NASA Astrophysics Data System (ADS)

      Albert, Philipp J.; Erdmann, Thorsten; Schwarz, Ulrich S.

      2014-09-01

      Tissue cells are in a state of permanent mechanical tension that is maintained mainly by myosin II minifilaments, which are bipolar assemblies of tens of myosin II molecular motors contracting actin networks and bundles. Here we introduce a stochastic model for myosin II minifilaments as two small myosin II motor ensembles engaging in a stochastic tug-of-war. Each of the two ensembles is described by the parallel cluster model that allows us to use exact stochastic simulations and at the same time to keep important molecular details of the myosin II cross-bridge cycle. Our simulation and analytical results reveal a strong dependence of myosin II minifilament dynamics on environmental stiffness that is reminiscent of the cellular response to substrate stiffness. For small stiffness, minifilaments form transient crosslinks exerting short spikes of force with negligible mean. For large stiffness, minifilaments form near permanent crosslinks exerting a mean force which hardly depends on environmental elasticity. This functional switch arises because dissociation after the power stroke is suppressed by force (catch bonding) and because ensembles can no longer perform the power stroke at large forces. Symmetric myosin II minifilaments perform a random walk with an effective diffusion constant which decreases with increasing ensemble size, as demonstrated for rigid substrates with an analytical treatment.

    15. Cycles, stochasticity and density dependence in pink salmon population dynamics

      PubMed Central

      Krkošek, Martin; Hilborn, Ray; Peterman, Randall M.; Quinn, Thomas P.

      2011-01-01

      Complex dynamics of animal populations often involve deterministic and stochastic components. A fascinating example is the variation in magnitude of 2-year cycles in abundances of pink salmon (Oncorhynchus gorbuscha) stocks along the North Pacific rim. Pink salmon have a 2-year anadromous and semelparous life cycle, resulting in odd- and even-year lineages that occupy the same habitats but are reproductively isolated in time. One lineage is often much more abundant than the other in a given river, and there are phase switches in dominance between odd- and even-year lines. In some regions, the weak line is absent and in others both lines are abundant. Our analysis of 33 stocks indicates that these patterns probably result from stochastic perturbations of damped oscillations owing to density-dependent mortality caused by interactions between lineages. Possible mechanisms are cannibalism, disease transmission, food depletion and habitat degradation by which one lineage affects the other, although no mechanism has been well-studied. Our results provide comprehensive empirical estimates of lagged density-dependent mortality in salmon populations and suggest that a combination of stochasticity and density dependence drives cyclical dynamics of pink salmon stocks. PMID:21147806

    16. Distribution of population averaged observables in stochastic gene expression

      NASA Astrophysics Data System (ADS)

      Bhattacharyya, Bhaswati; Kalay, Ziya

      2014-03-01

      Observation of phenotypic diversity in a population of genetically identical cells is often linked to the stochastic nature of chemical reactions involved in gene regulatory networks. We investigate the distribution of population averaged gene expression levels as a function of population, or sample size for several stochastic gene expression models to find out to what extent population averaged quantities reflect the underlying mechanism of gene expression. We consider three basic gene regulation networks corresponding to transcription with and without gene state switching and translation. Using analytical expressions for the probability generating function (pgf) of observables and Large Deviation Theory, we calculate the distribution of population averaged mRNA and protein levels as a function of model parameters and population size. We validate our results using stochastic simulations also report exact results on the asymptotic properties of population averages which show qualitative differences for different models. We calculate the skewness and coefficient of variance for pgfs to estimate the sample size required for population average that contains information about gene expression models. This is relevant to experiments where a large number of data points are unavailable.

    17. Cycles, stochasticity and density dependence in pink salmon population dynamics.

      PubMed

      Krkosek, Martin; Hilborn, Ray; Peterman, Randall M; Quinn, Thomas P

      2011-07-01

      Complex dynamics of animal populations often involve deterministic and stochastic components. A fascinating example is the variation in magnitude of 2-year cycles in abundances of pink salmon (Oncorhynchus gorbuscha) stocks along the North Pacific rim. Pink salmon have a 2-year anadromous and semelparous life cycle, resulting in odd- and even-year lineages that occupy the same habitats but are reproductively isolated in time. One lineage is often much more abundant than the other in a given river, and there are phase switches in dominance between odd- and even-year lines. In some regions, the weak line is absent and in others both lines are abundant. Our analysis of 33 stocks indicates that these patterns probably result from stochastic perturbations of damped oscillations owing to density-dependent mortality caused by interactions between lineages. Possible mechanisms are cannibalism, disease transmission, food depletion and habitat degradation by which one lineage affects the other, although no mechanism has been well-studied. Our results provide comprehensive empirical estimates of lagged density-dependent mortality in salmon populations and suggest that a combination of stochasticity and density dependence drives cyclical dynamics of pink salmon stocks. PMID:21147806

    18. A stochastic killing system for biological containment of Escherichia coli.

      PubMed Central

      Klemm, P; Jensen, L B; Molin, S

      1995-01-01

      Bacteria with a stochastic conditional lethal containment system have been constructed. The invertible switch promoter located upstream of the fimA gene from Escherichia coli was inserted as expression cassette in front of the lethal gef gene deleted of its own natural promoter. The resulting fusion was placed on a plasmid and transformed to E. coli. The phenotype connected with the presence of such a plasmid was to reduce the population growth rate with increasing significance as the cell growth rate was reduced. In very fast growing cells, there was no measurable effect on growth rate. When a culture of E. coli harboring the plasmid comprising the containment system is left as stationary cells in suspension without nutrients, viability drops exponentially over a period of several days, in contrast to the control cells, which maintain viability nearly unaffected during the same period of time. Similar results were obtained with a strain in which the killing cassette was inserted in the chromosome. In competition with noncontained cells during growth, the contained cells are always outcompeted. Stochastic killing obtained by the fim-gef fusion is at present relevant only as a containment approach for E. coli, but the model may be mimicked in other organisms by using species-specific stochastic expression systems. PMID:7574584

    19. Degree Distribution of Position-Dependent Ball-Passing Networks in Football Games

      NASA Astrophysics Data System (ADS)

      Narizuka, Takuma; Yamamoto, Ken; Yamazaki, Yoshihiro

      2015-08-01

      We propose a simple stochastic model describing the position-dependent ball-passing network in football (soccer) games. In this network, a player in a certain area in a divided field is a node, and a pass between two nodes corresponds to an edge. Our stochastic process model is characterized by the consecutive choice of a node depending on its intrinsic fitness. We derive an explicit expression for the degree distribution and find that the derived distribution reproduces that for actual data reasonably well.

    20. Gaming Simulation: A General Classification.

      ERIC Educational Resources Information Center

      Cecchini, Arnaldo; Frisenna, Adriana

      1987-01-01

      Reviews the problems of classifying gaming techniques and suggests a heuristic approach as one solution. Definitions of simulation, models, role, and game and play are discussed to help develop a classification based on a technique called gaming simulation. (Author/LRW)

    1. Gaming Frequency and Academic Performance

      ERIC Educational Resources Information Center

      Ip, Barry; Jacobs, Gabriel; Watkins, Alan

      2008-01-01

      There are numerous claims that playing computer and video games may be educationally beneficial, but there has been little formal investigation into whether or not the frequency of exposure to such games actually affects academic performance. This paper explores the issue by analysing the relationships between gaming frequency--measured as the

    2. Can Video Games Be Educational?

      ERIC Educational Resources Information Center

      Criswell, Chad

      2009-01-01

      One of the biggest debates among music educators today is about whether or not video games are a valid educational tool. As far back as the early 1990s, teachers were using games such as Sid Meier's Civilization to reinforce history and social studies concepts, but until recently games that dealt with areas of music education have been few and far

    3. Card Games for Learning Chinese.

      ERIC Educational Resources Information Center

      Yao, Ted; McGinnis, Scott

      Five card games for use in beginning to advanced level Chinese language classrooms or outside the classroom are described. The games require a flat playing surface, the prescribed deck of cards, and three to five students. Instructor supervision is minimal for all but one of the games, and all provide healthy competition and fun with a purpose.

    4. "Voyager": An Educational Card Game

      ERIC Educational Resources Information Center

      Smith, David Ryan

      2003-01-01

      "Voyager" is an educational card game involving scientific satellites, developed for use in schools with children aged 9 to 13 years. The idea of the game is to improve pupils' knowledge about the large number of scientific satellites there are in space in a fun way, while also practising numeracy skills. Several copies of the game were produced

    5. "Voyager": An Educational Card Game

      ERIC Educational Resources Information Center

      Smith, David Ryan

      2003-01-01

      "Voyager" is an educational card game involving scientific satellites, developed for use in schools with children aged 9 to 13 years. The idea of the game is to improve pupils' knowledge about the large number of scientific satellites there are in space in a fun way, while also practising numeracy skills. Several copies of the game were produced…

    6. Video Games and Digital Literacies

      ERIC Educational Resources Information Center

      Steinkuehler, Constance

      2010-01-01

      Today's youth are situated in a complex information ecology that includes video games and print texts. At the basic level, video game play itself is a form of digital literacy practice. If we widen our focus from the "individual player + technology" to the online communities that play them, we find that video games also lie at the nexus of a

    7. External Validation of Simulation Games.

      ERIC Educational Resources Information Center

      Norris, Dwight R.; Snyder, Charles A.

      1982-01-01

      Discusses research into the external validity of simulation games used in education, i.e., the degree to which the games correspond to the real-life situations they are designed to simulate. An exploratory study examines the validity of a business game and potential problems of validity research are examined. (JJD)

    8. Game Plan: Save Lives, Winterize!

      ERIC Educational Resources Information Center

      Children & Animals, 1988

      1988-01-01

      Describes a learning center game which deals with the needs of dogs and cats in the winter months. Provides background information on the potential risks to pets during cold weather. Contains the game cards, along with assembly instructions and the rules of the games. (TW)

    9. Games, the Socialization of Conflict.

      ERIC Educational Resources Information Center

      Sutton-Smith, Brian

      The function of games in a society is discussed in this paper. An earlier definition of games as a concretistic way of processing information of cultural antitheses is enlarged to include a more bio-adaptive definition: the game is also a socialization of conflict. This view is compared and contrasted with those of Sigmund Freud and G. H. Mead.…

    10. Recreational Games for Physical Education

      ERIC Educational Resources Information Center

      Hume, Donald

      2005-01-01

      Recreational games can be incorporated into physical education programs to encourage play and activity among students during their leisure time. Students can play their own games during recess, before or after school, during intramural programs, or in their neighborhood with family and friends. This article describes five such games namely:

    11. Computerized History Games: Narrative Options

      ERIC Educational Resources Information Center

      Kee, Kevin

      2011-01-01

      How may historians best express history through computer games? This article suggests that the answer lies in correctly correlating historians' goals for teaching with the capabilities of different kinds of computer games. During the development of a game prototype for high school students, the author followed best practices as expressed in the

    12. Gaming Research for Technology Education

      ERIC Educational Resources Information Center

      Clark, Aaron C.; Ernst, Jeremy

      2009-01-01

      This study assesses the use of gaming to teach Science, Technology, Engineering, and Mathematics (STEM) in public education. The intent of the investigation was to identify attitudes about gaming and its use in education, as well as the need to utilize gaming as a platform to serve as an integrator of STEM subject matter. Participants included

    13. Alliances in "The Hunger Games"

      ERIC Educational Resources Information Center

      Painter, Judith

      2012-01-01

      This lesson plan is based on "The Hunger Games" by Suzanne Collins. Characters in "The Hunger Games" form alliances both inside and outside the arena. Katniss and Gale form alliances within District 12. Katniss, Peeta, and the other tributes form alliances for a variety of reasons during the Games. An alliance means that "someone's got your back"…

    14. Brain-Building Math Games.

      ERIC Educational Resources Information Center

      Jung, Loretta Welk

      1983-01-01

      Index cards, masking tape, pizza shells, golf tees, and empty soda bottles can be used to make manipulative objects to be used in children's mathematics games. Twenty-two games that provide practice in number drills and problem solving are described, along with instructions for making objects needed for the games. (PP)

    15. Games, the Socialization of Conflict.

      ERIC Educational Resources Information Center

      Sutton-Smith, Brian

      The function of games in a society is discussed in this paper. An earlier definition of games as a concretistic way of processing information of cultural antitheses is enlarged to include a more bio-adaptive definition: the game is also a socialization of conflict. This view is compared and contrasted with those of Sigmund Freud and G. H. Mead.

    16. Gaming and Gamification Part II

      ERIC Educational Resources Information Center

      Mallon, Melissa

      2013-01-01

      Just as academic gaming in general cannot be limited to any one topic or genre, the "Public Services Quarterly" Internet Resources column is not limited to a single entry on gaming and gamification in libraries. Public services librarians interested in designing their own games have many successful examples to draw from. The previous…

    17. Alliances in "The Hunger Games"

      ERIC Educational Resources Information Center

      Painter, Judith

      2012-01-01

      This lesson plan is based on "The Hunger Games" by Suzanne Collins. Characters in "The Hunger Games" form alliances both inside and outside the arena. Katniss and Gale form alliances within District 12. Katniss, Peeta, and the other tributes form alliances for a variety of reasons during the Games. An alliance means that "someone's got your back"

    18. Gaming and Gamification Part II

      ERIC Educational Resources Information Center

      Mallon, Melissa

      2013-01-01

      Just as academic gaming in general cannot be limited to any one topic or genre, the "Public Services Quarterly" Internet Resources column is not limited to a single entry on gaming and gamification in libraries. Public services librarians interested in designing their own games have many successful examples to draw from. The previous

    19. A Stochastic Collocation Algorithm for Uncertainty Analysis

      NASA Technical Reports Server (NTRS)

      Mathelin, Lionel; Hussaini, M. Yousuff; Zang, Thomas A. (Technical Monitor)

      2003-01-01

      This report describes a stochastic collocation method to adequately handle a physically intrinsic uncertainty in the variables of a numerical simulation. For instance, while the standard Galerkin approach to Polynomial Chaos requires multi-dimensional summations over the stochastic basis functions, the stochastic collocation method enables to collapse those summations to a one-dimensional summation only. This report furnishes the essential algorithmic details of the new stochastic collocation method and provides as a numerical example the solution of the Riemann problem with the stochastic collocation method used for the discretization of the stochastic parameters.

    20. Enhanced algorithms for stochastic programming

      SciTech Connect

      Krishna, A.S.

      1993-09-01

      In this dissertation, we present some of the recent advances made in solving two-stage stochastic linear programming problems of large size and complexity. Decomposition and sampling are two fundamental components of techniques to solve stochastic optimization problems. We describe improvements to the current techniques in both these areas. We studied different ways of using importance sampling techniques in the context of Stochastic programming, by varying the choice of approximation functions used in this method. We have concluded that approximating the recourse function by a computationally inexpensive piecewise-linear function is highly efficient. This reduced the problem from finding the mean of a computationally expensive functions to finding that of a computationally inexpensive function. Then we implemented various variance reduction techniques to estimate the mean of a piecewise-linear function. This method achieved similar variance reductions in orders of magnitude less time than, when we directly applied variance-reduction techniques directly on the given problem. In solving a stochastic linear program, the expected value problem is usually solved before a stochastic solution and also to speed-up the algorithm by making use of the information obtained from the solution of the expected value problem. We have devised a new decomposition scheme to improve the convergence of this algorithm.

    1. Stochastic models: theory and simulation.

      SciTech Connect

      Field, Richard V., Jr.

      2008-03-01

      Many problems in applied science and engineering involve physical phenomena that behave randomly in time and/or space. Examples are diverse and include turbulent flow over an aircraft wing, Earth climatology, material microstructure, and the financial markets. Mathematical models for these random phenomena are referred to as stochastic processes and/or random fields, and Monte Carlo simulation is the only general-purpose tool for solving problems of this type. The use of Monte Carlo simulation requires methods and algorithms to generate samples of the appropriate stochastic model; these samples then become inputs and/or boundary conditions to established deterministic simulation codes. While numerous algorithms and tools currently exist to generate samples of simple random variables and vectors, no cohesive simulation tool yet exists for generating samples of stochastic processes and/or random fields. There are two objectives of this report. First, we provide some theoretical background on stochastic processes and random fields that can be used to model phenomena that are random in space and/or time. Second, we provide simple algorithms that can be used to generate independent samples of general stochastic models. The theory and simulation of random variables and vectors is also reviewed for completeness.

    2. Switching power pulse system

      DOEpatents

      Aaland, K.

      1983-08-09

      A switching system for delivering pulses of power from a source to a load using a storage capacitor charged through a rectifier, and maintained charged to a reference voltage level by a transistor switch and voltage comparator. A thyristor is triggered to discharge the storage capacitor through a saturable reactor and fractional turn saturable transformer having a secondary to primary turn ratio N of n:l/n = n[sup 2]. The saturable reactor functions as a soaker'' while the thyristor reaches saturation, and then switches to a low impedance state. The saturable transformer functions as a switching transformer with high impedance while a load coupling capacitor charges, and then switches to a low impedance state to dump the charge of the storage capacitor into the load through the coupling capacitor. The transformer is comprised of a multilayer core having two secondary windings tightly wound and connected in parallel to add their output voltage and reduce output inductance, and a number of single turn windings connected in parallel at nodes for the primary winding, each single turn winding linking a different one of the layers of the multilayer core. The load may be comprised of a resistive beampipe for a linear particle accelerator and capacitance of a pulse forming network. To hold off discharge of the capacitance until it is fully charged, a saturable core is provided around the resistive beampipe to isolate the beampipe from the capacitance until it is fully charged. 5 figs.

    3. Thermionic gas switch

      DOEpatents

      Hatch, G.L.; Brummond, W.A.; Barrus, D.M.

      1984-04-05

      The present invention is directed to an improved temperature responsive thermionic gas switch utilizing a hollow cathode and a folded emitter surface area. The folded emitter surface area of the thermionic switch substantially increases the on/off ratio by changing the conduction surface area involved in the two modes thereof. The improved switch of this invention provides an on/off ratio of 450:1 compared to the 10:1 ratio of the prior known thermionic switch, while providing for adjusting the on current. In the improved switch of this invention the conduction area is made small in the off mode, while in the on mode the conduction area is made large. This is achieved by utilizing a folded hollow cathode configuration and utilizing a folded emitter surface area, and by making the dimensions of the folds small enough so that a space charge will develop in the convolutions of the folds and suppress unignited current, thus limiting the current carrying surface in the off mode.

    4. Atomic Scale Plasmonic Switch.

      PubMed

      Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

      2016-01-13

      The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level. PMID:26670551

    5. Nanoscale memristive radiofrequency switches.

      PubMed

      Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C; Xia, Qiangfei

      2015-01-01

      Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 10(12) with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications. PMID:26108890

    6. Stochastic gating and drug-ribosome interactions.

      PubMed

      Vaiana, Andrea C; Sanbonmatsu, Kevin Y

      2009-02-27

      Gentamicin is a potent antibiotic that is used in combination therapy for inhalation anthrax disease. The drug is also often used in therapy for methicillin-resistant Staphylococcusaureus. Gentamicin works by flipping a conformational switch on the ribosome, disrupting the reading head (i.e., 16S ribosomal decoding bases 1492-1493) used for decoding messenger RNA. We use explicit solvent all-atom molecular simulation to study the thermodynamics of the ribosomal decoding site and its interaction with gentamicin. The replica exchange molecular dynamics simulations used an aggregate sampling of 15 mus when summed over all replicas, allowing us to explicitly calculate the free-energy landscape, including a rigorous treatment of enthalpic and entropic effects. Here, we show that the decoding bases flip on a timescale faster than that of gentamicin binding, supporting a stochastic gating mechanism for antibiotic binding, rather than an induced-fit model where the bases only flip in the presence of a ligand. The study also allows us to explore the nonspecific binding landscape near the binding site and reveals that, rather than a two-state bound/unbound scenario, drug dissociation entails shuttling between many metastable local minima in the free-energy landscape. Special care is dedicated to validation of the obtained results, both by direct comparison to experiment and by estimation of simulation convergence. PMID:19146858

    7. Delay-dependent fuzzy static output feedback control for discrete-time fuzzy stochastic systems with distributed time-varying delays.

      PubMed

      Xia, ZhiLe; Li, JunMin; Li, JiangRong

      2012-11-01

      This paper is concerned with the delay-dependent H(?) fuzzy static output feedback control scheme for discrete-time Takagi-Sugeno (T-S) fuzzy stochastic systems with distributed time-varying delays. To begin with, the T-S fuzzy stochastic system is transformed to an equivalent switching fuzzy stochastic system. Then, based on novel matrix decoupling technique, improved free-weighting matrix technique and piecewise Lyapunov-Krasovskii function (PLKF), a new delay-dependent H(?) fuzzy static output feedback controller design approach is first derived for the switching fuzzy stochastic system. Some drawbacks existing in the previous papers such as matrix equalities constraint, coordinate transformation, the same output matrices, diagonal structure constraint on Lyapunov matrices and BMI problem have been eliminated. Since only a set of LMIs is involved, the controller parameters can be solved directly by the Matlab LMI toolbox. Finally, two examples are provided to illustrate the validity of the proposed method. PMID:22795723

    8. Altered Brain Reactivity to Game Cues After Gaming Experience.

      PubMed

      Ahn, Hyeon Min; Chung, Hwan Jun; Kim, Sang Hee

      2015-08-01

      Individuals who play Internet games excessively show elevated brain reactivity to game-related cues. This study attempted to test whether this elevated cue reactivity observed in game players is a result of repeated exposure to Internet games. Healthy young adults without a history of excessively playing Internet games were recruited, and they were instructed to play an online Internet game for 2 hours/day for five consecutive weekdays. Two control groups were used: the drama group, which viewed a fantasy TV drama, and the no-exposure group, which received no systematic exposure. All participants performed a cue reactivity task with game, drama, and neutral cues in the brain scanner, both before and after the exposure sessions. The game group showed an increased reactivity to game cues in the right ventrolateral prefrontal cortex (VLPFC). The degree of VLPFC activation increase was positively correlated with the self-reported increase in desire for the game. The drama group showed an increased cue reactivity in response to the presentation of drama cues in the caudate, posterior cingulate, and precuneus. The results indicate that exposure to either Internet games or TV dramas elevates the reactivity to visual cues associated with the particular exposure. The exact elevation patterns, however, appear to differ depending on the type of media experienced. How changes in each of the regions contribute to the progression to pathological craving warrants a future longitudinal study. PMID:26252933

    9. Game Theory and Social Psychology: Conformity Games

      NASA Astrophysics Data System (ADS)

      Alessio, Danielle; Kilgour, D. Marc

      2011-11-01

      Game models can contribute to understanding of how social biases and pressures to conform can lead to puzzling behaviour in social groups. A model of the psychological biases false uniqueness and false consensus is set out. The model predicts the phenomenon of pluralistic ignorance, which is well-studied in social psychology, showing how it arises as a result of the prevalence of false uniqueness and the desire to conform. An efficient method is developed for finding Nash equilibria of the model under certain restrictions.

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

      PubMed Central

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

      2015-01-01

      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. PMID:26658221

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

      PubMed

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

      2015-01-01

      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. PMID:26658221

    12. Stochastic simulations of the origins and implications of long-tailed distributions in gene expression

      PubMed Central

      Krishna, Sandeep; Banerjee, Bidisha; Ramakrishnan, T. V.; Shivashankar, G. V.

      2005-01-01

      Gene expression noise results in protein number distributions ranging from long-tailed to Gaussian. We show how long-tailed distributions arise from a stochastic model of the constituent chemical reactions and suggest that, in conjunction with cooperative switches, they lead to more sensitive selection of a subpopulation of cells with high protein number than is possible with Gaussian distributions. Single-cell-tracking experiments are presented to validate some of the assumptions of the stochastic simulations. We also examine the effect of DNA looping on the shape of protein distributions. We further show that when switches are incorporated in the regulation of a gene via a feedback loop, the distributions can become bimodal. This might explain the bimodal distribution of certain morphogens during early embryogenesis. PMID:15772163

    13. Model reduction for slow–fast stochastic systems with metastable behaviour

      SciTech Connect

      Bruna, Maria; Computational Science Laboratory, Microsoft Research, Cambridge CB1 2FB ; Chapman, S. Jonathan; Smith, Matthew J.

      2014-05-07

      The quasi-steady-state approximation (or stochastic averaging principle) is a useful tool in the study of multiscale stochastic systems, giving a practical method by which to reduce the number of degrees of freedom in a model. The method is extended here to slow–fast systems in which the fast variables exhibit metastable behaviour. The key parameter that determines the form of the reduced model is the ratio of the timescale for the switching of the fast variables between metastable states to the timescale for the evolution of the slow variables. The method is illustrated with two examples: one from biochemistry (a fast-species-mediated chemical switch coupled to a slower varying species), and one from ecology (a predator–prey system). Numerical simulations of each model reduction are compared with those of the full system.

    14. Stochastic determination of matrix determinants.

      PubMed

      Dorn, Sebastian; Ensslin, Torsten A

      2015-07-01

      Matrix determinants play an important role in data analysis, in particular when Gaussian processes are involved. Due to currently exploding data volumes, linear operations-matrices-acting on the data are often not accessible directly but are only represented indirectly in form of a computer routine. Such a routine implements the transformation a data vector undergoes under matrix multiplication. While efficient probing routines to estimate a matrix's diagonal or trace, based solely on such computationally affordable matrix-vector multiplications, are well known and frequently used in signal inference, there is no stochastic estimate for its determinant. We introduce a probing method for the logarithm of a determinant of a linear operator. Our method rests upon a reformulation of the log-determinant by an integral representation and the transformation of the involved terms into stochastic expressions. This stochastic determinant determination enables large-size applications in Bayesian inference, in particular evidence calculations, model comparison, and posterior determination. PMID:26274302

    15. Stochastic determination of matrix determinants

      NASA Astrophysics Data System (ADS)

      Dorn, Sebastian; Enlin, Torsten A.

      2015-07-01

      Matrix determinants play an important role in data analysis, in particular when Gaussian processes are involved. Due to currently exploding data volumes, linear operationsmatricesacting on the data are often not accessible directly but are only represented indirectly in form of a computer routine. Such a routine implements the transformation a data vector undergoes under matrix multiplication. While efficient probing routines to estimate a matrix's diagonal or trace, based solely on such computationally affordable matrix-vector multiplications, are well known and frequently used in signal inference, there is no stochastic estimate for its determinant. We introduce a probing method for the logarithm of a determinant of a linear operator. Our method rests upon a reformulation of the log-determinant by an integral representation and the transformation of the involved terms into stochastic expressions. This stochastic determinant determination enables large-size applications in Bayesian inference, in particular evidence calculations, model comparison, and posterior determination.

    16. Stochastic excitation of stellar oscillations

      NASA Astrophysics Data System (ADS)

      Samadi, Reza

      2001-05-01

      Since more than about thirty years, solar oscillations are thought to be excited stochastically by the turbulent motions in the solar convective zone. It is currently believed that oscillations of stars lower than 2 solar masses - which possess an upper convective zone - are excited stochastically by turbulent convection in their outer layers. Providing that accurate measurements of the oscillation amplitudes and damping rates are available it is possible to evaluate the power injected into the modes and thus - by comparison with the observations - to constrain current theories. A recent theoretical work (Samadi & Goupil, 2001; Samadi et al., 2001) supplements and reinforces the theory of stochastic excitation of star vibrations. This process was generalized to a global description of the turbulent state of their convective zone. The comparison between observation and theory, thus generalized, will allow to better know the turbulent spectrum of stars, and this in particular thanks to the COROT mission.

    17. Principal axes for stochastic dynamics

      NASA Astrophysics Data System (ADS)

      Vasconcelos, V. V.; Raischel, F.; Haase, M.; Peinke, J.; Wächter, M.; Lind, P. G.; Kleinhans, D.

      2011-09-01

      We introduce a general procedure for directly ascertaining how many independent stochastic sources exist in a complex system modeled through a set of coupled Langevin equations of arbitrary dimension. The procedure is based on the computation of the eigenvalues and the corresponding eigenvectors of local diffusion matrices. We demonstrate our algorithm by applying it to two examples of systems showing Hopf bifurcation. We argue that computing the eigenvectors associated to the eigenvalues of the diffusion matrix at local mesh points in the phase space enables one to define vector fields of stochastic eigendirections. In particular, the eigenvector associated to the lowest eigenvalue defines the path of minimum stochastic forcing in phase space, and a transform to a new coordinate system aligned with the eigenvectors can increase the predictability of the system.

    18. Microfabricated triggered vacuum switch

      DOEpatents

      Roesler, Alexander W. (Tijeras, NM); Schare, Joshua M. (Albuquerque, NM); Bunch, Kyle (Albuquerque, NM)

      2010-05-11

      A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

    19. Switching power supply

      DOEpatents

      Mihalka, A.M.

      1984-06-05

      The invention is a repratable capacitor charging, switching power supply. A ferrite transformer steps up a dc input. The transformer primary is in a full bridge configuration utilizing power MOSFETs as the bridge switches. The transformer secondary is fed into a high voltage, full wave rectifier whose output is connected directly to the energy storage capacitor. The transformer is designed to provide adequate leakage inductance to limit capacitor current. The MOSFETs are switched to the variable frequency from 20 to 50 kHz to charge a capacitor from 0.6 kV. The peak current in a transformer primary and secondary is controlled by increasing the pulse width as the capacitor charges. A digital ripple counter counts pulses and after a preselected desired number is reached an up-counter is clocked.

    20. Optical computer switching network

      NASA Technical Reports Server (NTRS)

      Clymer, B.; Collins, S. A., Jr.

      1985-01-01

      The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

    1. SWITCH user's manual

      NASA Technical Reports Server (NTRS)

      1987-01-01

      The planning program, SWITCH, and its surrounding changed-goal-replanning program, Runaround, are described. The evolution of SWITCH and Runaround from an earlier planner, DEVISER, is recounted. SWITCH's plan representation, and its process of building a plan by backward chaining with strict chronological backtracking, are described. A guide for writing knowledge base files is provided, as are narrative guides for installing the program, running it, and interacting with it while it is running. Some utility functions are documented. For the sake of completeness, a narrative guide to the experimental discrepancy-replanning feature is provided. Appendices contain knowledge base files for a blocksworld domain, and a DRIBBLE file illustrating the output from, and user interaction with, the program in that domain.

    2. Dynamic switch matrix for the TDMA satellite switching system

      NASA Technical Reports Server (NTRS)

      Ho, P. T.; Wisniewski, J. H.; Pelose, J. R.; Perasso, H. M.

      1982-01-01

      Future high capacity satellite communication systems require signal processing on board satellites. The on-board signal processing includes switching of RF signals between multiple antennas to provide interconnection between the uplink and downlink beams. This paper describes the development of a dynamic switch matrix for a TDMA satellite switching system to be used in the next generation communications satellites. In this paper, a dynamic switch matrix, which includes the microwave switch matrix, the distribution control unit and the timing source, will be described. Several different microwave switch matrix architectures and switching devices were evaluated and compared. A unique coupler crossbar switch matrix architecture with dual-gate field effect transistor as switching element was developed. Experimental results of both microwave switch matrix (MSM) and distribution control unit (DCU) are presented. These test results verify the MSM with coupler crossbar architecture and dual-gate FET as switching element will meet the future SS-TDMA system requirements. Finally, the reliability of the dynamic switch matrix is addressed. The analysis shows reliability of 0.9981 for 7 year space operation can be achieved for the designed dynamic switch matrix.

    3. Comments on optical stochastic cooling

      SciTech Connect

      K.Y. Ng, S.Y. Lee and Y.K. Zhang

      2002-10-08

      An important necessary condition for transverse phase space damping in the optical stochastic cooling with transit-time method is derived. The longitudinal and transverse damping dynamics for the optical stochastic cooling is studied. The authors also obtain an optimal laser focusing condition for laser-beam interaction in the correction undulator. The amplification factor and the output peak power of the laser amplifier are found to differ substantially from earlier publications. The required power is large for hadron colliders at very high energy.

    4. Stochastic Optimization of Complex Systems

      SciTech Connect

      Birge, John R.

      2014-03-20

      This project focused on methodologies for the solution of stochastic optimization problems based on relaxation and penalty methods, Monte Carlo simulation, parallel processing, and inverse optimization. The main results of the project were the development of a convergent method for the solution of models that include expectation constraints as in equilibrium models, improvement of Monte Carlo convergence through the use of a new method of sample batch optimization, the development of new parallel processing methods for stochastic unit commitment models, and the development of improved methods in combination with parallel processing for incorporating automatic differentiation methods into optimization.

    5. Analysis of system drought for Manitoba Hydro using stochastic methods

      NASA Astrophysics Data System (ADS)

      Akintug, Bertug

      Stochastic time series models are commonly used in the analysis of large-scale water resources systems. In the stochastic approach, synthetic flow scenarios are generated and used for the analysis of complex events such as multi-year droughts. Conclusions drawn from such analyses are only plausible to the extent that the underlying time series model realistically represents the natural variability of flows. Traditionally, hydrologists have favoured autoregressive moving average (ARMA) models to describe annual flows. In this research project, a class of model called Markov-Switching (MS) model (also referred to as a Hidden Markov model) is presented as an alternative to conventional ARMA models. The basic assumption underlying this model is that a limited number of flow regimes exists and that each flow year can be classified as belonging to one of these regimes. The persistence of and switching between regimes is described by a Markov chain. Within each regime, it is assumed that annual flows follow a normal distribution with mean and variance that depend on the regime. The simplicity of this model makes it possible to derive a number of model characteristics analytically such as moments, autocorrelation, and crosscorrelation. Model estimation is possible with the maximum likelihood method implemented using the Expectation Maximization (EM) algorithm. The uncertainty in the model parameters can be assessed through Bayesian inference using Markov Chain Monte Carlo (MCMC) methods. A Markov-Switching disaggregation (MSD) model is also proposed in this research project to disaggregate higher-level flows generated using the MS model into lower-level flows. The MSD model preserves the additivity property because for a given year both the higher-level and lower-level variables are generated from normal distributions. The 2-state MS and MSD models are applied to Manitoba Hydro's system along with more conventional first order autoregressive and disaggregation models and parameter and missing data uncertainty are identified in the analysis of system drought.

    6. Activation-induced B cell fates are selected by intracellular stochastic competition.

      PubMed

      Duffy, Ken R; Wellard, Cameron J; Markham, John F; Zhou, Jie H S; Holmberg, Ross; Hawkins, Edwin D; Hasbold, Jhagvaral; Dowling, Mark R; Hodgkin, Philip D

      2012-01-20

      In response to stimulation, B lymphocytes pursue a large number of distinct fates important for immune regulation. Whether each cell's fate is determined by external direction, internal stochastic processes, or directed asymmetric division is unknown. Measurement of times to isotype switch, to develop into a plasmablast, and to divide or to die for thousands of cells indicated that each fate is pursued autonomously and stochastically. As a consequence of competition between these processes, censorship of alternative outcomes predicts intricate correlations that are observed in the data. Stochastic competition can explain how the allocation of a proportion of B cells to each cell fate is achieved. The B cell may exemplify how other complex cell differentiation systems are controlled. PMID:22223740

    7. Partial ASL extensions for stochastic programming.

      Energy Science and Technology Software Center (ESTSC)

      2010-03-31

      partially completed extensions for stochastic programming to the AMPL/solver interface library (ASL).modeling and experimenting with stochastic recourse problems. This software is not primarily for military applications

    8. Watermarking textures in video games

      NASA Astrophysics Data System (ADS)

      Liu, Huajian; Berchtold, Waldemar; Schäfer, Marcel; Lieb, Patrick; Steinebach, Martin

      2014-02-01

      Digital watermarking is a promising solution to video game piracy. In this paper, based on the analysis of special challenges and requirements in terms of watermarking textures in video games, a novel watermarking scheme for DDS textures in video games is proposed. To meet the performance requirements in video game applications, the proposed algorithm embeds the watermark message directly in the compressed stream in DDS files and can be straightforwardly applied in watermark container technique for real-time embedding. Furthermore, the embedding approach achieves high watermark payload to handle collusion secure fingerprinting codes with extreme length. Hence, the scheme is resistant to collusion attacks, which is indispensable in video game applications. The proposed scheme is evaluated in aspects of transparency, robustness, security and performance. Especially, in addition to classical objective evaluation, the visual quality and playing experience of watermarked games is assessed subjectively in game playing.

    9. 36. INTERIOR VIEW, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING SWITCHING ...

      Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

      36. INTERIOR VIEW, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING SWITCHING LEVERS FROM OPERATOR'S POSITION - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

    10. 43. OBLIQUE VIEW, GREEN SWITCH TOWER, COS COB, SHOWING SWITCH ...

      Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

      43. OBLIQUE VIEW, GREEN SWITCH TOWER, COS COB, SHOWING SWITCH LEVER ASSEMBLAGE AND DISPLAY BOARD - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

    11. 35. END VIEW, INTERIOR, SHOWING SWITCHING LEVERS, BERK SWITCH TOWER, ...

      Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

      35. END VIEW, INTERIOR, SHOWING SWITCHING LEVERS, BERK SWITCH TOWER, SOUTH NORWALK - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

    12. 41. INTERIOR VIEW, GREEN SWITCH TOWER, COS COB, SHOWING SWITCH ...

      Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

      41. INTERIOR VIEW, GREEN SWITCH TOWER, COS COB, SHOWING SWITCH LEVER ASSEMBLAGE AND DISPLAY BOARD - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

    13. Hybrid solid state switch replaces motor- driven power switch

      NASA Technical Reports Server (NTRS)

      Booth, R. A.; Schloss, A. I.

      1967-01-01

      Hybrid solid state switch replaces existing motor-driven power switches used on spacecraft. It uses a transistor circuit to limit the open circuit voltage and allow small relay contacts to handle high transient currents at reasonable cycle life.

    14. Main electrical switch banks, plant switch house, looking to the ...

      Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

      Main electrical switch banks, plant switch house, looking to the North - Bureau of Mines Metallurgical Research Laboratory, Original Building, Date Street north of U.S. Highway 93, Boulder City, Clark County, NV

    15. Seasonally forced disease dynamics explored as switching between attractors

      NASA Astrophysics Data System (ADS)

      Keeling, Matt J.; Rohani, Pejman; Grenfell, Bryan T.

      2001-01-01

      Biological phenomena offer a rich diversity of problems that can be understood using mathematical techniques. Three key features common to many biological systems are temporal forcing, stochasticity and nonlinearity. Here, using simple disease models compared to data, we examine how these three factors interact to produce a range of complicated dynamics. The study of disease dynamics has been amongst the most theoretically developed areas of mathematical biology; simple models have been highly successful in explaining the dynamics of a wide variety of diseases. Models of childhood diseases incorporate seasonal variation in contact rates due to the increased mixing during school terms compared to school holidays. This ‘binary’ nature of the seasonal forcing results in dynamics that can be explained as switching between two nonlinear spiral sinks. Finally, we consider the stability of the attractors to understand the interaction between the deterministic dynamics and demographic and environmental stochasticity. Throughout attention is focused on the behaviour of measles, whooping cough and rubella.

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

      NASA Astrophysics Data System (ADS)

      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.

    17. Transport in a stochastic magnetic field

      SciTech Connect

      White, R.B.; Wu, Yanlin . Plasma Physics Lab.); Rax, J.M. . Dept. de Recherches sur la Fusion Controlee)

      1992-01-01

      Collisional heat transport in a stochastic magnetic field configuration is investigated. Well above stochastic threshold, a numerical solution of a Chirikov-Taylor model shows a short-time nonlocal regime, but at large time the Rechester-Rosenbluth effective diffusion is confirmed. Near stochastic threshold, subdiffusive behavior is observed for short mean free paths. The nature of this subdiffusive behavior is understood in terms of the spectrum of islands in the stochastic sea.

    18. Transport in a stochastic magnetic field

      SciTech Connect

      White, R.B.; Wu, Yanlin; Rax, J.M.

      1992-09-01

      Collisional heat transport in a stochastic magnetic field configuration is investigated. Well above stochastic threshold, a numerical solution of a Chirikov-Taylor model shows a short-time nonlocal regime, but at large time the Rechester-Rosenbluth effective diffusion is confirmed. Near stochastic threshold, subdiffusive behavior is observed for short mean free paths. The nature of this subdiffusive behavior is understood in terms of the spectrum of islands in the stochastic sea.

    19. The Hamiltonian Mechanics of Stochastic Acceleration

      SciTech Connect

      Burby, J. W.

      2013-07-17

      We show how to nd the physical Langevin equation describing the trajectories of particles un- dergoing collisionless stochastic acceleration. These stochastic di erential equations retain not only one-, but two-particle statistics, and inherit the Hamiltonian nature of the underlying microscopic equations. This opens the door to using stochastic variational integrators to perform simulations of stochastic interactions such as Fermi acceleration. We illustrate the theory by applying it to two example problems.

    20. University Prosperity Game. Final report

      SciTech Connect

      Boyack, K.W.; Berman, M.

      1996-03-01

      Prosperity Games are an outgrowth and adaptation of move/countermove and seminar War Games. Prosperity Games are simulations that explore complex issues in a variety of areas including economics, politics, sociology, environment, education and research. These issues can be examined from a variety of perspectives ranging from a global, macroeconomic and geopolitical viewpoint down to the details of customer/supplier/market interactions in specific industries. All Prosperity Games are unique in that both the game format and the player contributions vary from game to game. This report documents the University Prosperity Game conducted under the sponsorship of the Anderson Schools of Management at the University of New Mexico. This Prosperity Game was initially designed for the roadmap making effort of the National Electronics Manufacturing Initiative (NEMI) of the Electronics Subcommittee of the Civilian Industrial Technology Committee under the aegis of the National Science and Technology Council. The game was modified to support course material in MGT 508, Ethical, Political, and Social Environment of Business. Thirty-five students participated as role players. In this educational context the game`s main objectives were to: (1) introduce and teach global competitiveness and business cultures in an experiential classroom setting; (2) explore ethical, political, and social issues and address them in the context of global markets and competition; and (3) obtain non-government views regarding the technical and non-technical (i.e., policy) issues developed in the NEMI roadmap-making endeavor. The negotiations and agreements made during the game, along with the student journals detailing the players feelings and reactions to the gaming experience, provide valuable insight into the benefits of simulation as an advanced learning tool in higher education.