Player Control Research Articles

Distributed Minmax Strategy for Multiplayer Games: Stability, Robustness, and Algorithms.

This article studies a distributed minmax strategy for multiplayer games and develops reinforcement learning (RL) algorithms to solve it. The proposed minmax strategy is distributed, in the sense that it finds each player's optimal control policy without knowing all the other players' policies. Each player obtains its distributed control policy by solving a distributed algebraic Riccati equation in a multiplayer noncooperative game. This policy is found against the worst policies of all the other players. We guarantee the existence of distributed minmax solutions and study their L2 and asymptotic stabilities. Under mild conditions, the resulting minmax control policies are shown to improve robust gain and phase margins of multiplayer systems compared to the standard linear-quadratic regulator controller. Distributed minmax solutions are found using both model-based policy iteration and data-driven off-policy RL algorithms. Simulation examples verify the proposed formulation and its computational efficiency over the nondistributed Nash solutions.

On a discrete game problem with non-convex control vectograms

In a normed space of finite dimension, a discrete game problem with fixed duration is considered. The terminal set is determined by the condition that the norm of the phase vector belongs to a segment with positive ends. In this paper, a set defined by this condition is called a ring. At each moment, the vectogram of the first player's controls is a certain ring. The controls of the second player at each moment are taken from balls with given radii. The goal of the first player is to lead a phase vector to the terminal set at a fixed time. The goal of the second player is the opposite. In this paper, necessary and sufficient termination conditions are found, and optimal controls of the players are constructed.

The effect of different trunk training on rugby player's balance control ability ―Practical study using slackline―

The effect of different trunk training on rugby player's balance control ability ―Practical study using slackline―

Stackelberg-Theoretic Approach for Performance Improvement in Fuzzy Systems.

This paper investigates the robust control for dynamical systems subject to uncertainty. The uncertainty is assumed to be (possibly fast) time varying and bounded. The bound is unknown but lies within a prescribed fuzzy set (hence the fuzzy dynamical system). We propose an approach for the robust control design which is implemented in two steps. First, a class of robust controls is proposed based on tunable parameters. The proposed controls are deterministic and are not conventionally IF-THEN rules based. By the Lyapunov minimax approach, we prove that the proposed controls are able to guarantee deterministic system performance, namely, uniform boundedness and ultimate uniform boundedness. Second, optima seeking from the proposed controls is considered to improve fuzzy system performance. We formulate the optima-seeking problem as a two-player (one leader and one follower) Stackelberg game by developing two cost functions, each of which is in charge of one tunable parameter (i.e., the player). Each cost function consists of an average fuzzy system performance index and the associated player's control effort. We show that the solution of the optimal design problem (i.e., the optima of the tunable parameters), which is called the Stackelberg strategy, always exists and how to obtain the backwards-induction outcome is provided. Simulation results on the walking control of a biped robot model are presented for demonstration.

Sound Play: Video Games and the Musical Imagination by William Cheng (review)

Reviewed by: Sound Play: Video Games and the Musical Imagination by William Cheng Jessica L. Getman Sound Play: Video Games and the Musical Imagination. By William Cheng. (Oxford Music/Media Series.) Oxford: Oxford University Press, 2014. [xviii, 240 p. ISBN 9780199969968 (hardcover), $99; ISBN 9780199969975 (paperback), $24.95; (e-book), various.] Music examples, illustrations, endnotes, bibliography, index, online media. William Cheng’s Sound Play interrogates the relationship between video games, their music, and their sounds, examining how “players of games oscillate between being [End Page 162] in and out of control, playing and being played, and acting and being acted upon by the game’s barrage of audiovisual stimuli” (p. 9). This book presents important arguments regarding game sound as a social device, and is, moreover, a pleasant read, personable, and suffused with clever, and often poignant, puns (of which the book’s title is only one). Cheng’s text is extensively researched and intelligently conceived, addressing some of the more current and charged concerns regarding game culture and player agency. Over the course of five case studies, focusing on the video games Fallout 3 (2008), Final Fantasy VI (1994), Silent Hill (1999), The Lord of the Rings Online (2007), and Team Fortress 2 (2007), Cheng addresses violence, nostalgia, horror, authenticity, and gender politics. He extends a growing field defined by such scholars as Karen Collins (Game Sound: An Introduction to the History, Theory, and Practice of Video Game Music and Sound Design [Cambridge, MA: MIT Press, 2008]), Kiri Miller (Playing Along: Digital Games, YouTube, and Virtual Performance [Oxford: Oxford University Press, 2012]), and K. J. Donnelly, William Gibbons, and Neil Lerner (Music in Video Games: Studying Play [New York: Routledge, 2014]). Cheng builds on this foundation by casting a wide theoretical net and engaging in ethnography, demonstrating a keen ear for the musical sensitivity and values demonstrated by designers and gamers alike. Sound Play combines a number of methodologies, including analyses of narrative, music, and game structure. Of particular note is Cheng’s commitment to ethnographic research, making use of participant observation, various forms of interview, research in online forums, analysis of gamer videos posted to YouTube, and descriptions of live performances of game music. Theoretically, he draws from multiple fields, including scholarship on video game history and theory, video game music, and technology and culture, as well as genre theory, gender and queer theory, and sound studies (including voice and noise studies). His footnotes include many pointers to research in parallel subjects, including actor-–network theory, music as torture, patternicity, virtuosity, authenticity, posthumanism, gender masquerading and “coming out” online, and speech as act. Most of the research for this book was completed as part of Cheng’s Ph.D. dissertation at Harvard University (2012); the book, in fact, draws extensively from this document. One significant and beneficial addition, however, is Sound Play’s chapter on Final Fantasy VI, which allows Cheng to explore nostalgia, a central topic in research on video game communities. After an introduction that discusses player agency and interrogates the notion of the real–virtual divide, Sound Play charges out of the gate with a particularly contentious issue: violence in video games. Focusing on Fallout 3, which uses a post-apocalyptic society and ruined landscape as the basis of its narrative, chapter 1, “A Tune at the End of the World,” challenges the presumed agency the player is given over the game’s music as well as the ways in which this music, in turn, affects the player’s control over the entire game. Cheng identifies the three radio channels from which players can choose and describes their constitutive styles. Most significantly, Cheng notes that the radio stations’ repetitiveness seems particularly suited to a postapocalyptic world; very few new musical pieces, and certainly no new musical styles, arise from a society decimated by tragedy. Cheng reads this in light of Theodor Adorno’s edict that “to write poetry after Auschwitz is barbaric” (p. 26)—in Fallout 3, creativity after extreme violence is unthinkable. Cheng contends that the music produced by these radio stations, when heard alongside the acts of violence perpetrated by the game and its players, creates a sense of contextual dissonance that can...

Motor Behavior and Anticipation – A Pilot Study of Junior Tennis Players

Anticipation represents the tennis player's ability to forecast the future actions of its competitor. Tennis is, in general, an anticipation and space-time coordination sport. This study wishes to emphasize the importance of anticipation, in the efficiency of the tennis player's neuromuscular control, at a junior level. The study was conducted on 20 junior tennis players from the national lot. The measurement of the players was carried out in three steps: measuring the space-time anticipation with the Vienna Test Sport System testing battery, measuring the neuromuscular control, with the help of the condition simulator and measuring the balance with the aid of the Balance Platform.

Decision support of Bad Player Identification in MOBA Games using PageRank based Evidence Accumulation and Normal Distribution based Confidence Interval

On-line game service is the hottest game genre today, and one of major on-line game is MOBA (multiplayer online battle arena) game. In MOBA games, the collaboration of team players and team strategy are vital elements together, besides the individual player's game control capability. Thus important issue for the MOBA service providers is to detect bad players showing abnormal plays or appearances in games with embedded malicious intentions. Previous approach had been presented to cope with such players; however they have not yet shown any promising results to judge each player. In this paper, we propose an efficient and automatic abnormal player decision support scheme using PageRank and normal distribution to find and judge bad players. Our scheme computes BPR (bad player ranking) for each user, and BPR can be used in service provider’s final decision to decide a specific user as an abnormal player. Our scheme has main advantage that it requires small computational efforts to identify bad players, because we utilize PageRank algorithm which shows efficient computation and information search capability.

The Interactive Theater of Video Games: The Gamer as Playwright, Director, and Actor

In storytelling, films, and novels, is traditionally an observer, and by necessity a passive observer. In these media artists can often be seen as telling rather than sharing stories. To be sure, author provides space for a readers imaginative input, but you cannot change words. Both theater and, more recently, video games have been experimenting with, twisting, and turning on its head this traditional view of Unless you're Roger Ebert and believe that video games cannot and will never be art, video game designers, writers, and directors are starting to blur lines between interactive theater and games. (1) In recently released video game Gone Home, for example, is a young college student who returns home from Europe to find her parents missing and a note from her younger sister taped to front door. Reviewing game in The New York Times, Chris Suellentrop comments on work's gripping fiction, its closeness to literary realism. One of designers, Steve Gaynor, influenced by current hit Sleep No More, an interactive theater production to be examined later in this essay, observes that in Gone Home audience ... occupies same three-dimensional space as fictional inhabitants and that inside that space, players, like theatergoers, can choose where to focus their attention. Lucy Pebbles writing in The Observer speaks of game as if it were a video equivalent to audience's experience with Sleep No More: You piece together a sense of who everyone is and what happened through seemingly disconnected items and evidence hidden around house. And those connections are intentionally weak. It allows plot and conclusions to take place in mind of and not in action of game. For her, Gone Home takes gaming element away from screen, and into your head, making room for player/audience directly ... because they are alive to flexibility of choice and narrative. (2) We use video games and interactive theater here as reverse mirrors to raise larger aesthetic questions. Is this increased role for audience, whether offstage or at controls, ultimate goal, reality of both media? What happens to concept of plot or narrative when becomes a collaborator with playwright or with game designer? Is notion of author challenged, reduced, potentially rendered irrelevant with time, as audience's or player's control grows exponentially in these more recent experiments in theater and in video games? And is video game now a legitimate rival of, some would even go so far as to say successor to, legitimate theater which has been described, even dismissed as the fabulous invalid? (3) When filtering play through his or her own life experiences, needs, agenda, interests, preoccupations, spectator in theater has always been a player in loose sense of that word. But idea of spectator's having a direct role in action onstage or even a hand in plot, becoming a player in literal sense as it applies to interactive video games, is of more recent origin. The 1960s saw numerous productions that drew onstage, willingly or not, thereby blurring line between stage and house. As a result, performances were half scripted, half improv, latter coming into play when members joined actors onstage, their role ranging from nonverbal members of a crowd to new characters in ongoing story. Behind such experiments was principle of, even political need for, inclusivity, making spectator more than a passive receptor and challenging what innovators saw as stilted, even undemocratic theater of past. (4) An actor friend tells of a workshop performance in 1980s that offered a variation on such inclusion of audience. Those present were confronted with an actor dressed as Frankenstein's creature, standing motionless before them. …

Network vulnerability analysis of the Player command and control protocol

This paper demonstrates command and control protocols for remotely–piloted vehicles can be susceptible to cyber attacks and provides recommendations to mitigate these attacks while minimising impact to resource–constrained platforms. The Player project is an open–source effort providing a control interface specification and software framework for abstracting robot hardware. This research presents five exploits that compromise vulnerabilities in Player's command and control protocol. This work also demonstrates that Internet Protocol Security (IPsec) is capable of mitigating the vulnerabilities discovered in Player's command and control protocol. A cost function is defined to synthesise exploit success, CPU utilisation, and network load into a single scalar metric that can be used to compare the different IPsec protocols. Results show that in a scenario when exploits are likely, IPsec AH+ESP is the preferred defense protocol because of its relatively low CPU and network overhead and ability to defeat the exploits implemented in this research.

An Impact Study of the Design of Exergaming Parameters on Body Intensity from Objective and Gameplay-Based Player Experience Perspectives, Based on Balance Training Exergame

Kinect-based exergames allow players to undertake physical exercise in an interactive manner with visual stimulation. Previous studies focused on investigating physical fitness based on calories or heart rate to ascertain the effectiveness of exergames. However, designing an exergame for specific training purposes, with intensity levels suited to the needs and skills of the players, requires the investigation of motion performance to study player experience.This study investigates how parameters of a Kinect-based exergame, combined with balance training exercises, influence the balance control ability and intensity level the player can tolerate, by analyzing both objective and gameplay-based player experience, and taking enjoyment and difficulty levels into account.The exergame tested required participants to maintain their balance standing on one leg within a posture frame (PF) while a force plate evaluated the player's balance control ability in both static and dynamic gaming modes. The number of collisions with the PF depended on the frame's travel time for static PFs, and the leg-raising rate and angle for dynamic PFs. In terms of center of pressure (COP) metrics, significant impacts were caused by the frame's travel time on MDIST-AP for static PFs, and the leg-raising rate on MDIST-ML and TOTEX for dynamic PFs. The best static PF balance control performance was observed with a larger frame offset by a travel time of 2 seconds, and the worst performance with a smaller frame and a travel time of 1 second. The best dynamic PF performance was with a leg-raising rate of 1 second at a 45-degree angle, while the worst performance was with a rate of 2 seconds at a 90-degree angle.The results demonstrated that different evaluation methods for player experience could result in different findings, making it harder to study the design of those exergames with training purposes based on player experience.

A model of motor inhibition for a complex skill: Baseball batting.

The ability to inhibit an ongoing action in response to a signal from the environment is important for many perceptual-motor actions. This paper examines a particular example of this behavior: attempting to inhibit or "check" a swing in baseball batting. A model of motor inhibition in batting is proposed. In the model there are three different inhibition signals (out of range launch angle, early expected-actual trajectory discrepancy, and late expected-actual trajectory discrepancy) resulting in four possible response outcomes for the batter's swing (full swing, inhibited swing, partial response, or interrupted swing). The predictions of the model were compared with the actual batting performance of 20 baseball players using a high-fidelity batting simulator. The proportions of the different response outcomes could be explained by the inhibition model for 17/20 of the batters in the study. These findings suggest that models of motor inhibition developed for simple, discrete tasks can be applied to complex, multistage behaviors. This batting inhibition model could be used to provide a quantitative measure of a player's bat control for training and player-screening purposes. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Asymptotic ε-Nash Equilibrium for 2nd Order Two-Player Nonzero-sum Singular LQ Games with Decentralized Control

We propose a new equilibrium concept: asymptotic ε-Nash equilibrium for 2***nd order two-player nonzero-sum games where each player has a control-free cost functional quadratic in the system states over an infinite horizon and each player's control strategy is constrained to be continuous linear state feedback. Based on each player's singular control problem, the asymptotic ε-Nash equilibrium implemented by partial state feedback is constructed and the feedback gains can be found by solving a group of algebraic equations which involves the system coefficients and weighting matrices in the cost functionals. As an illustration of the theories discussed in this paper, a numerical example is given where the partial state feedback gains can be found explicitly in terms of the system coefficients and weighting matrices in the cost functionals.

Voice-controlled electronic musical instrument

An electronic, voice-controlled musical instrument called the Vocolo, in which the player hums into the mouthpiece, and the device imitates the sound of a musical instrument whose pitch and volume change in response to the player's voice is disclosed. The player is given the impression of playing the actual instrument and controlling it intimately with the fine nuances of his voice. The invention comprises techniques for pitch quantization that provide esthetically pleasing note transitions, mechanisms for song recording that are suited for rhythmic repeated playback and performance evaluation of the player's pitch control, techniques related to expressive control and pitch detection, and techniques for mitigating the effect of pitch detection errors. Embodiments are disclosed for providing finger/hand interaction for expressive control, a microphone enclosure that mitigates audio feedback, and for providing rhythmic feedback to the player through mechanical vibrations induced in the device.

The sufficient conditions of stability for the value function of a differential game in terms of singular points

Differential games in which the payoff is the time required to reach a given terminal set (optimum-time games) are considered. The Bellman-Isaacs equation must have a classical solution in domains where the value function of the game is smooth. At singular points, where smooth branches of the solution interlock, more complicated conditions must hold, in terms of directional derivatives. A class of games is found and two types of singularities are described such that the aforementioned conditions follow automatically from the geometrical properties of the singularities: the class of games with autonomous separated dynamics in which one player's control set is a June segment. An appropriate theorem is proved. The result is used to construct the value function of a game in which there are three types of singular surfaces: dispersal, equivocal, and switching surfaces.

Compact disc players in the laboratory: experiments in optical storage, error correction, and optical fiber communication

The compact disc player is a synergy of optics, communication theory, digital signal processing, and control engineering. This familiar consumer product may be employed as a cost-effective laboratory instrument to teach the fundamentals of optical storage, error detection and correction, and optical communication. The compact disc audio system, from analog input, through optical storage and distribution, to audio reproduction, provides an excellent model of a complete real-world optical transmission and storage system. A series of experiments, which illustrate some of the more significant operational principles of the compact disc player, are presented in this contribution. Optical read-out and the physics of information density are explored through a set of experiments in optical storage. Error detection and correction are studied experimentally by evaluating the performance of the compact disc player's error control system. The design of an optical fiber communication system is studied by extracting the channel bit stream from a compact disc player, transmitting it over an optical fiber link, and then reinserting it back into the compact disc player for audio reproduction.

The transient behaviour of models of bowed-string motion.

Theoretical models of the action of a bowed string may be able to shed light on differences of "playability" between different violins. Subjective judgements seem to be concerned, at least in part, with the robustness with which one particular oscillation regime of the string (the "Helmholtz motion") may be obtained under different bowing conditions. In this paper, after a review of bowed-string modelling, systematic simulation is used to obtain plots of the basin of attraction of the Helmholtz motion in a particular subspace of the player's control space. Variations in the size and structure of this basin of attraction are seen when parameters of the problem are varied, and some physical interpretation of these variations is given. Some parallels and contrasts are pointed out between the particular features of the bowed string as a nonlinear system, and the range of more familiar dynamical systems. (c) 1995 American Institute of Physics.

Computer modelling of violin playing

Abstract In the last 15 years there has been significant progress in the understanding of the oscillations of musical instruments. This progress comes in part from the increased understanding of the basic physical mechanisms involved in the oscillations, but some of the major successes arise from a successful adaptation of the physical models to rapid computer calculation of the waveforms of oscillation. In this article we review research on the bowed string, where computation speed is now allowing a fruitful exploration of the enormous parameter space needed to describe the instrument, its strings and the string player's control of them in a musical context.

MEASURABLE STRATEGIES IN DIFFERENTIAL GAMES

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

A type of linear game with mixed constraints on the controls

A game is considered in which the first person's control is subject to a geometric and an integral constraint. The second person can choose a control, subject to the geometric constraint. The game ends at a given instant. The sets of controls values and the terminal set are of the same type. The conditions are found for the game to end from a given initial position. The player's controls are constructed, and an example is given. Differential games with mixed constraints were considered in /1, 2/. The present types of game may not satisfy the regularity condition /2, 3/.

Differential encounter-evasion game for a parabolic system under integral constraints on the player's controls: PMM vol. 41, n≗ 2, 1977, pp. 202–209

Differential encounter-evasion game for a parabolic system under integral constraints on the player's controls: PMM vol. 41, n≗ 2, 1977, pp. 202–209