基于博弈理论的农田能量异构网络节点协同资源利用

针对无线传感器网络中耗能不均问题,以及可再生能源节点在农田无线传感器网络中应用的具体情况,将博弈理论引入无线传感器网络能耗问题研究中,建立了基于博弈理论的节点成簇方法,实现提高可再生能源利用率、均衡非可再生能源节点能耗的目标。方法首先建立簇收益与簇内节点收益评估模型,进行簇收益计算、簇内的两类能量异构节点个体收益的计算。在计算簇收益和节点收益的基础上进行节点成簇博弈,使得成簇方案向收益更高的策略空间进行跳转,最终达到博弈中的均衡状态。仿真实验表明,通过博弈进行无线传感器网络成簇,能够充分利用可再生能源节点能量,降低和均衡非可再生能源节点能耗,最终达到延长网络寿命的目标。     

Game‐Based Valley‐Fill Charging Coordination for Large‐Population Plug‐in Electric Vehicles

Charging coordination of large‐population autonomous plug‐in electric vehicles (PEVs) in the power grid can be formulated as a class of constrained optimization problems. To overcome the computational complexity, a game‐based method is proposed for the charging problems of the PEV population, which is composed of homogeneous subpopulations, such that individuals update their best charging strategies simultaneously with respect to a common electricity price determined by the total demand. To mitigate the oscillation behavior caused by the greedy behavior for the cheap electricity by individuals, a deviation cost is introduced to penalize against the deviation of the individual strategy from the average value of the homogeneous subpopulation. By adopting a proper deviation cost and following a best strategy update mechanism, the game systems may converge to the socially optimal valley‐fill Nash equilibrium. Simulation examples are studied to illustrate the results.     

Proportional and double imitation rules for spectrum access in cognitive radio networks

In this paper, we tackle the problem of opportunistic spectrum access in large-scale cognitive radio networks, where the unlicensed Secondary Users (SUs) access the frequency channels partially occupied by the licensed Primary Users (PUs). Each channel is characterized by an availability probability unknown to the SUs. We apply population game theory to model the spectrum access problem and develop distributed spectrum access policies based on imitation, a behavior rule widely applied in human societies consisting of imitating successful behaviors. We develop two imitation-based spectrum access policies based on the basic Proportional Imitation (PI) rule and the more advanced Double Imitation (DI) rule given that a SU can only imitate the other SUs operating on the same channel. A systematic theoretical analysis is presented for both policies on the induced imitation dynamics and the convergence properties of the proposed policies to the Nash equilibrium. Simple and natural, the proposed imitation-based spectrum access policies can be implemented distributedly based on solely local interactions and thus is especially suited in decentralized adaptive learning environments as cognitive radio networks.     

Remediating Theatre in a Digital Proscenium

The paper examines and evaluates the transposition of live theatre performance into a digital multimedia environment utilising QuickTime (or equivalent) movie software for use on standard PCs. Writers such as Brenda Laurel have discussed the close correspondences between theatre and computers, and CD-ROM authoring software such as Director clearly adopts theatrical paradigms and terminology. The differences between attending a performance in a theatre and viewing a recording on a computer screen are outlined, and how these two experiences differ in what is expected from the audience/user. The distortions inherent in any video recording of a theatre event are explored, with particular reference to differentials in performance scale. The flickering, low-r esolution picture typifying video playback on CD-ROMs is then argued to be a positive virtue in the remediation of theatrical footage, and far preferable to full-screen video recordings. A number of reasons are proposed which explore ideas around documentary realism, visual and aesthetic convention, totemic fetishisation, and Brecht's alienation theory. It is suggested that the small-window digital movie placed within the larger multimedia screen where other graphical codes and images can co-exist and interact with the video footage, creates a dual proscenium that is poetic, evocative, and inherently theatrical.     

Playful gender swapping: user attitudes toward gender in MMORPG avatar customisation

Avatar gender is a basic element of an MMORPG user's identity. Gender customisation in a virtual space is an expansion of identity, an attempt to express oneself in more diverse ways. A survey showed that numerous users manage gender-swapped avatars, and men in particular prefer using female avatars. This study analysed user attitudes toward gender using a Q methodology. In the process, it confirmed the generalisations and motivating factors of gender swapping. The advanced graphic technology and high degree of freedom available in recent MMORPGs has led to an increased demand for avatar physical qualities, and the motives that underlie gender selection have become more diverse and complex. In particular, the notion of experimental and playful creation through customisation has been illuminated and treated as the core consideration of game design.     

A suboptimal joint bandwidth and power allocation for cooperative relay networks＂ a cooperative game theoretic approach

In commercial networks, user nodes operating on batteries are assumed to be selfish to consume their resources (i.e., bandwidth and power) solely maximizing their own benefits (e.g., the received signal-to-noise ratios (SNRs) and datarates). In this paper, a cooperative game theoretical framework is proposed to jointly perform the bandwidth and power allocation for selfish cooperative relay networks. To ensure a fair and efficient resource sharing between two selfish user nodes, we assume that either node can act as a source as well as a potential relay for each other and either node is willing to seek cooperative relaying only if the datarate achieved through cooperation is not lower than that achieved through noncooperation (i.e., direct transmission) by consuming the same amount of bandwidth and power resource. Define the cooperative strategy of a node as the number of bandwidth and power that it is willing to contribute for relaying purpose. The two node joint bandwidth and power allocation (JBPA) problem can then be formulated as a cooperative game. Since the Nash bargaining solution (NBS) to the JBPA game (JBPAG) is computationally difficult to obtain, we divide it into two subgames, i.e., the bandwidth allocation game (BAG) and the power allocation game (PAG). We prove that both the subgames have unique NBS. And then the suboptimal NBS to the JBPAG can be achieved by solving the BAG and PAG sequentially. Simulation results show that the proposed cooperative game scheme is efficient in that the performance loss of the NBS result to that of the maximal overall data-rate scheme is small while the maximal-rate scheme is unfair. The simulation results also show that the NBS result is fair in that both nodes could experience better performance than they work independently and the degree of cooperation of a node only depends on how much contribution its partner can make to improve its own performance.     

游戏中图像内容情感语义的分析与研究

针对目前游戏中忽略情感因素的问题,在游戏场景中引入情感语义的概念,提出基于情感语义的游戏场景图像检索系统和情感计算研究情感信息的数字化处理方法,采用支持向量机算法建立场景图像内容和其所表达的情感语义之间的联系。来建立一个能感知识别人的情感,能对人的情感做出智能反应的游戏系统,从而使人机交互更加和谐化。     

启发式A^＊算法在游戏寻路中的应用

文章在对A＊搜索和启发式搜索技术进行详细分析与研究的基础上,将A＊算法应用于flash游戏中的寻路,并在此基础上分析出A＊算法的实际应用时间效率和空间效率。     

3D游戏开发中的碰撞检测算法研究

碰撞检测在三维游戏开发中是必不可少的环节。目前,主流游戏引擎大多采用基于层次包围体的碰撞检测算法,其基本思想是用一个相对简单的包围体逼近场景中复杂的物体。文中对当前三维游戏开发中常用的四种基于包围体的算法作了理论分析,并通过试验对四种不同的包围体算法作了性能测试。试验结果表明,紧密性越好的包围体其精度越高,但时间消耗也高。因此,在具体的游戏开发中,应根据实际游戏的特殊情况进行算法选用,才能取得较好的效果。     

在Torque中实现武器丢弃

介绍如何使用脚本语言在Torque引擎中实现武器的丢弃功能。