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
Stochastic Differential Games with Asymmetric Information
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.
Stochastic Games with Average Payoff Criterion
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.
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)
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.
Stochastic game dynamics under demographic fluctuations.
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
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.
Stochastic Switching of Cell Fate in Microbes.
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
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
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 playersâ 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.
Two Different Approaches to Nonzero-Sum Stochastic Differential Games
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.
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 gamesâŠ
Stochastic gene expression in switching environments.
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
Stochastic switching as a survival strategy in fluctuating environments.
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
Stochastic Local Search for Core Membership Checking in Hedonic Games
NASA Astrophysics Data System (ADS)
KeinĂ€nen, 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.
Stochastic Heterogeneous Interaction Promotes Cooperation in Spatial Prisoner's Dilemma Game
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
Stochastic heterogeneous interaction promotes cooperation in spatial prisoner's dilemma game.
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
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
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.
Partial synchronization in stochastic dynamical networks with switching communication channels
NASA Astrophysics Data System (ADS)
Huang, Chi; Ho, Daniel W. C.; Lu, Jianquan; Kurths, Jürgen
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.
A stochastic transcriptional switch model for single cell imaging data
Hey, Kirsty L.; Momiji, Hiroshi; Featherstone, Karen; Davis, Julian R.E.; White, Michael R.H.; Rand, David A.; FinkenstĂ€dt, BĂ€rbel
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 birthâdeath 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
A Stochastic Maximum Principle for a Stochastic Differential Game of a Mean-Field Type
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.
Stability analysis of switched stochastic neural networks with time-varying delays.
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
Adaptive role switching promotes fairness in networked ultimatum game
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
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.
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 âȘ V W âȘ 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.
Robust stability of stochastic delayed additive neural networks with Markovian switching.
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
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.
The stochastic evolutionary game for a population of biological networks under natural selection.
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
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.
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.
Sufficient Stochastic Maximum Principle in a Regime-Switching Diffusion Model
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.
Stochastic gene expression modeling with Hill function for switch-like gene responses.
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
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 regionsâ cooperative and noncooperative optimal emission paths, which maximize the regionsâ 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
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
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 Ś 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].
PULSAR STATE SWITCHING FROM MARKOV TRANSITIONS AND STOCHASTIC RESONANCE
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 Â± 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.
An Element of Determinism in a Stochastic Flagellar Motor Switch
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 Îf and backward Îb intervals are investigated herein. We found that the steady-state probability density functions, P(Îf) and P(Îb), 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(Îf) and P(Îb) and found good agreement with the measurements. PMID:26554590
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.
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.
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
DOOM'd to Switch: Superior Cognitive Flexibility in Players of First Person Shooter Games.
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
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.
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.
Control of Stochastic and Induced Switching in Biophysical Networks
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
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.
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.
Designing a stochastic genetic switch by coupling chaos and bistability.
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
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.
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
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
A role of stochastic phenotype switching in generating mosaic endothelial cell heterogeneity.
Yuan, Lei; Chan, Gary C; Beeler, David; Janes, Lauren; Spokes, Katherine C; Dharaneeswaran, Harita; Mojiri, Anahita; Adams, William J; Sciuto, Tracey; Garcia-Cardeńa, Guillermo; Molema, Grietje; Kang, Peter M; Jahroudi, Nadia; Marsden, Philip A; Dvorak, Ann; Regan, Erzsébet 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
Stochastic game theory: For playing games, not just for doing theory
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
Stochastic switching in slow-fast systems: a large-fluctuation approach.
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
The effect of action video game experience on task-switching
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
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.
Learning dynamics in public goods games.
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
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.
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.
Cortical Contractility Triggers a Stochastic Switch to Fast Amoeboid Cell Motility
Ruprecht, Verena; Wieser, Stefan; Callan-Jones, Andrew; Smutny, Michael; Morita, Hitoshi; Sako, Keisuke; Barone, Vanessa; Ritsch-Marte, Monika; Sixt, Michael; Voituriez, Raphaël; 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
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.
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
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.
DĂ¶rrenbĂ€cher, Sandra; MĂŒller, Philipp M.; TrĂ¶ger, 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 (8â11 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
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.
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
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 wireâduring which the order-parameter fluctuates to zeroâinduce 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.
NASA Astrophysics Data System (ADS)
Liu, Qun
2015-09-01
In this paper, a stochastic n-species Gilpin-Ayala competitive model with Lévy 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 Lévy jumps and the stationary distribution of the Markovian chain. Moreover, some simulation figures are presented to confirm our main results.
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.
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 ?.
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.
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.
Stochastic switching of TiO2-based memristive devices with identical initial memory states
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
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
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.
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 âwhiteâ and âopaque,â 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.Â albicans functional homolog of the Saccharomyces cerevisiae transcriptional corepressor Cyc8, as a new regulator of white-opaque switching. In a or Î± 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
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
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
NASA Astrophysics Data System (ADS)
Varga, Levente; Vukov, Jeromos; Szabó, György
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.
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
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,
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,âŠ
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.
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 .
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.
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.
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 âeffective connectivityâ 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
NASA Astrophysics Data System (ADS)
Gammaitoni, Luca; HĂ€nggi, 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.
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 playâŠ
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
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.
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)
QB1 - Stochastic Gene Regulation
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.
Synchronization of noisy systems by stochastic signals
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}
Synchronization of noisy systems by stochastic signals.
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
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
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
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.
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.
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
Stochastic differential equations and numerical simulation for pedestrians
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.
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.
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,
Constrained Stochastic Extended Redundancy Analysis.
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
A Probabilistic-Numerical Approximation for an Obstacle Problem Arising in Game Theory
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.
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.
Multi-player games on the cycle
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
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.
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
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 mathâŠ
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
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
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
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
Noise-induced switches in network systems of the genetic toggle switch
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
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.
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 systemâs 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.
Optical switches and switching methods
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.
Stochastic memristive devices for computing and neuromorphic applications.
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
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.
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.
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)
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)
Stochastic learning in oxide binary synaptic device for neuromorphic computing
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
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.
Stochastic learning in oxide binary synaptic device for neuromorphic computing.
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
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.
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.
... 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 ...
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)
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
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)
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.
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,
Nanoscale resistive switching devices: mechanisms and modeling.
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
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.
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.
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
Stochastic memristive nature in Co-doped CeO{sub 2} nanorod arrays
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.
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.
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.
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.
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
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 thisâŠ
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)
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
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.
Switched power workshop. [Switched power electron guns
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)
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)
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, itâŠ
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
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)
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)
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 hookedâŠ
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
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.
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)
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.
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 whenâŠ
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 rarelyâŠ
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
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
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
... 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 ...
Play the Electrocardiogram Game
... 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 ...
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)
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
NASA Astrophysics Data System (ADS)
Chatterjee, Krishnendu; Horn, Florian; Löding, 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.
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,âŠ
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.
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
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
Path sampling with stochastic dynamics: Some new algorithms
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.
Viscosity Solutions of Systems of PDEs with Interconnected Obstacles and Switching Problem
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.
Deterministic characterization of stochastic genetic circuits
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
Stabilized multilevel Monte Carlo method for stiff stochastic differential equations
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.
Transcription Stochasticity of Complex Gene Regulation Models
Schwabe, Anne; Rybakova, Katja N.; Bruggeman, Frank J.
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
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 learningâŠ
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, oftenâŠ
... 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 ...
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 thatâŠ
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
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
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)
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.
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.
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.
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)
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.
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].
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.
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.
The Cell Cycle Switch Computes Approximate Majority
NASA Astrophysics Data System (ADS)
Cardelli, Luca; CsikĂĄsz-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.
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.
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.
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.
Information Security Analysis Using Game Theory and Simulation
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.
Latching relay switch assembly
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.
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.
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
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)
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 classifiedâŠ
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 personâŠ
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
Real-Time Strategy Game Training: Emergence of a Cognitive Flexibility Trait
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
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.
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
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.
Promotion of cooperation by payoff noise in a 2Ă2 game
NASA Astrophysics Data System (ADS)
Tanimoto, Jun
2007-10-01
A series of numerical simulations of a 2Ă2 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 PMNâs 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.
Stochastic gene expression as a many-body problem
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
Pathogen evolution in switching environments: a hybrid dynamical system approach.
Farkas, József Z; Hinow, Peter; Engelstädter, 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
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.
Stochastic modelling of intermittency.
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
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.
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)
... 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 ...
... 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 ...
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)
Intrinsic noise in game dynamical learning.
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
Dynamic Robust Games in MIMO Systems.
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 Itô's stochastic differential equations are discussed. PMID:21266314
NASA Astrophysics Data System (ADS)
Pierret, Frédéric
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.
NASA Astrophysics Data System (ADS)
Pierret, Frédéric
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.
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.
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.
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.
STOCHASTIC COOLING FOR BUNCHED BEAMS.
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.
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 agentsâ 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 systemâs global efficiency, are discussed.
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
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
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.âŠ
... 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 ...
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
... pĂĄgina en espaĂ±ol Video and Media Friend Finder (Game) Email Embed Grab this Game