移动自组网络N次空间重用的离散时间马氏链模型

移动自组网络(简称MANET)目前已经成为4G中的重要研究课题.本文在一个典型的随选型路由协议即动态源路由(DSR)协议的基础上,通过对信号强度进行分级来描述节点之间的相对距离,同时利用定向天线技术,建立了移动自组网络有空间重用的离散时间马氏链模型.通过计算平稳分布,进一步分析了节点相邻的概率和节点的平均邻居数两个基本的网络参数.并以定向天线发送信号的特性为基础,给出了一个具体实例,分析相应的参数.这对路由协议的评价和性能分析具有理论上的指导意义.     

Ad Hoc网络马氏模型路由维护的性能分析

Ad Hoc网络可以用许多数学模型来描述.本文以DSR协议为基础,把每条链边的长度看作是一个生灭过程,建立了马氏模型.在此模型中,我们考虑了空间可重用和请求分组带有跳限的情形.基于马氏模型,本文引入了链边Υ-时有效的概念,推导了链边有效的概率,得出了路由有效的条件概率和路由的平均恢复次数.     

科技成果转化团队知识网络中知识共享的博弈模型

构建了科技成果转化团队知识网络中知识共享的演化博弈模型,分析了核心节点的收益分配策略和普通节点的知识共享策略选择决策,得到了模型的均衡解、复制动态和稳定性,讨论了知识共享的影响因素,并进行了数值实验.研究结果表明:1)核心节点选择"高收益分配策略"、普通节点选择"知识共享策略"的概率是一个震荡性螺旋提升过程;2)影响普通节点知识共享的正向因素有"普通节点用于知识共享的资金投入量"等;3)影响核心节点收益分配策略选择的正向因素有"普通节点出入度期望值"等.     

立方体网络路由选择算法

本文利用图论理论 ,基于路由选择能力的概念 ,建立了一个有效的路由选择算法 ,该算法可以在含有节点故障和边故障的容错超立方体上使用 ,且具有较强的容错性 .     

Peer-to-Peer环境下基于分布式Kalman滤波的信用管理

Peer-to-Peer(P2P)环境下的信用管理对鼓励节点间的资源共享和抵制恶意节点的行为有重要的作用.针对目前P2P信用管理系统中全局信用值需要迭代计算,网络通信开销较大等问题,借鉴多传感器目标跟踪中的信息融合思想,提出了一种新的P2P环境下信用管理机制.建立了节点信用变化方程和测量方程,给出了节点全局信用值的分布式Kalman滤波估计方法,并讨论了恶意节点抑制问题.理论分析和仿真计算表明本文方法的信用值计算精度高、收敛速度快、资源开销小、对动态节点的适应性强并具有很好的可扩充性.     

马氏模型下移动自组网随选型路由协议特性分析

移动自组网络（简称MANET）因其移动性及无基础设施支持等特点已经成为无线通信网络中的热门问题．通过将一个MANET网络中每条链边的长度看作一个生灭过程,并且假设在泛洪过程中空间可以复用n次,建立了移动自组网络空间可复用的马氏模型,简记为n-SRBDM．在一个典型的随选型路由协议即动态源路由（DSR）协议的基础上,研究了网络的一些关键性能参数,给出了路由泛洪距离的概率分布和期望,限定泛洪步数时成功寻路的概率、发现τ-时有效路径及对称有效路径的概率,发现一条有效路径的平均时间等,对于路由维护过程,也引入并研究了一些网络性能参数,例如,路由恢复的平均频率,路由有效的平均时间．对于这些网络参数在空间可复用和空间不可复用两种情形下进行了比较．证明了空间可复用模型下的路由选择更为有效．     

基于动态数据驱动的改进灰色马尔科夫模型黄金价格预测

将黄金数据的尖峰厚尾、异方差性及杠杆效应等统计特征与马尔科夫概率转移矩阵所具有的动态变化规律结合,提出一种改进的灰色马尔科夫模型.模型首先对数据进行统计分析,建立相应的概率统计模型并用此模型对系统发展变化趋势进行拟合.在拟合序列的基础上利用马尔科夫链的动态转移变化建立状态转移概率矩阵,采用动态数据驱动原理对未来每一步数据进行动态预测.模型既是统计方法与数据动态驱动的结合,克服了传统的灰色马尔科夫模型中对数据内在统计规律的忽视,实证表明其预测精度较灰色马尔科夫模型预测高,具有较好的实用性.     

标准序列逻辑系统S_3中公式的概率真度理论

利用势为3的非均匀概率空间的无穷乘积在三值标准序列逻辑系统中引入了公式的概率真度概念,证明了全体公式的概率真度值之集在[0,1]中没有孤立点;利用概率真度定义了概率相似度和伪距离,进而建立了概率逻辑度量空间,证明了该空间中没有孤立点,为三值命题的近似推理理论提供了一种可能的框架.     

非对称企业合作创新网络演化博弈

当今快速发展的经济环境下,合作创新成为企业提高创新能力的有效途径.将企业按规模分成两类,建立企业合作创新耦合网络,采用概率型无条件模仿的策略更新规则,讨论企业间博弈策略随时间的演化规律.首先运用矩阵半张量积方法,将博弈的逻辑动态系统转化成离散时间系统,得到各企业每个时刻的策略;其次,给出所有企业以概率1参与合作创新的充要条件;最后,通过改变超额收益分配比例及违约成本、设计牵制控制算法使得所有企业以概率1选择合作创新策略.     

基于冰情检测环境的无线传感器网络路由协议研究

结合冰凌测报无线传感器网络中传感器节点能量受限、节点随着冰凌的产生与流动会出现在河道断面局部观测区域的冰凌测报无线传感器网络拓扑结构不断变化这一特性,提出了对贪婪周边无状态路由协议GPSR的改进策略GFSRI(GPSR-Improved),改进算法中采用图论模型,借助网络模拟器NS2(Network Simulator 2),对GPSR算法以及改进的路由策略GPSRI进行了模拟仿真实验,对路由算法中涉及到的关键参数的相关实验数据进行了处理分析.模拟仿真实验及评估结果表明,GPSRI在数据包转发的路由跳数、源和目的节点间端到端的传输时延方面与GPSR相比有较大的性能改进.     

Caching code chunks in dynamic documents

Authoring dynamic documents can become tedious for authors when a document contains one or more time consuming code chunks and each edit requires reprocessing all of the document. We introduce the weaver package that allows computationally expensive code chunks to be cached in order to speed up the edit/process/review cycle for dynamic documents authored using the Sweave framework.     

Competitive Algorithms for Relaxed List Update and Multilevel Caching

We study relaxed list update problem (RLUP), in which access requests are made to items stored in a list. The cost to access the jth item x_j is c_j, where c_i ≤ c_{i + 1} for all i. After the access, x_j can be repeatedly swapped, at no cost, with any item that precedes it in the list. This problem was introduced by Aggarwal et al. (1987, “Proc. 19th Symp. Theory of Computing,” pp. 305–313) as a model for the management of hierarchical memory that consists of a number of caches of increasing size and access time. They also proved that a version of LRU is C-competitive, for some C, for a restricted class of cost functions. We give an efficient offline algorithm that computes the optimal strategy for RLUP. We also show an elegant characterization of work functions for RLUP. We prove that move-to-front (MTF) is optimally competitive for RLUP with any cost function. An interesting feature of the proof is that it does not involve any estimates on the competitive ratio. Finally, we give a lower bound on the competitive ratio of online algorithms for RLUP.     

A Proof of the Kikuta–Ruckle Conjecture on Cyclic Caching of Resources

Suppose that a hider possesses a continuously divisible resource that he may distribute around a circle. The resources on a random arc in the circle are lost. The hider has a priori information on the length of the arc and he wants to maximize the probability that the retrieved portion exceeds a critical quantity, which is enough to survive on. We show that there exists an optimal resource distribution, which uses a finite number of point caches of equal size, establishing a conjecture of Kikuta and Ruckle. Our result is related to a conjecture of Samuels’ on-tail probabilities.     

Content essentialism

The paper offers some preliminary and rather unsystematic reflections about the question: Do Beliefs Have Their Contents Essentially? The question looks like it ought to be important, yet it is rarely discussed. Maybe that’s because content essentialism, i.e., the view that beliefs do have their contents essentially, is simply too obviously and trivially true to deserve much discussion. I sketch a common-sense argument that might be taken to show that content essentialism is indeed utterly obvious and/or trivial. Somewhat against this, I then point out that a “sexy” conclusion that is sometimes drawn from Putnam-Burge-style externalist arguments, namely that our mental states are not in our heads, presupposes content essentialism — which suggests that the view is not entirely trivial. Moreover, it seems intuitively that physicalists should reject the view: If beliefs are physical states, how could they have their propositional contents essentially? I distinguish three readings of the title question. Content essentialism does seem fairly obvious on the first two, but not so on the third. I argue that the common-sense argument mentioned earlier presupposes one of the first two readings but fails to apply to the third, on which ‘belief’ refers to belief-state tokens. That’s because ordinary belief individuation is silent about belief-state tokens. Token physicalists, I suggest, should indeed reject content essentialism about belief-state tokens. What about token dualists? One might think they ought to embrace content essentialism about belief-state tokens. I end with puzzling why this should be so.     

Time, Mode and Perceptual Content

Francois Recanati has recently argued that each perceptual state has two distinct kinds of content, complete and explicit content. According to Recanati, the former is a function of the latter and the psychological mode of perception. Furthermore, he has argued that explicit content is temporally neutral and that time-consciousness is a feature of psychological mode. In this paper it is argued, pace Recanati, that explicit content is not temporally neutral. Recanati??s position is initially presented. Three desiderata for a theory of time-consciousness are subsequently introduced. It is then argued that a theory locating time-consciousness as a feature of psychological mode will fail to satisfy these desiderata. In the last section the intentionality of memories is discussed. Using the notion of shiftable indexical, it is argued that memories have the same explicit content as perceptions, but that they nevertheless can have different conditions of satisfaction since they are entertained in different modes.     

Content evaluation and class symmetric functions

In this article we study the evaluation of symmetric functions on the alphabet of contents of a partition. Applying this notion of content evaluation to the computation of central characters of the symmetric group, we are led to the definition of a new basis of the algebra Λ of symmetric functions over that we call the basis of class symmetric functions.By definition this basis provides an algebra isomorphism between Λ and the Farahat-Higman algebra FH governing for all n the products of conjugacy classes in the center of the group algebra of the symmetric group . We thus obtain a calculus of all connexion coefficients of inside Λ. As expected, taking the homogeneous components of maximal degree in class symmetric functions, we recover the symmetric functions introduced by Macdonald to describe top connexion coefficients.We also discuss the relation of class symmetric functions to the asymptotic of central characters and of the enumeration of standard skew young tableaux. Finally we sketch the extension of these results to Hecke algebras.     

Gaussian Polynomials and Content Ideal in Pullbacks

This article deals mainly with rings (with zerodivisors) in which regular Gaussian polynomials have locally principal contents. Precisely, we show that if (T,M) is a local ring which is not a field, D is a subring of T/M such that qf(D) = T/M, h: T → T/M is the canonical surjection and R = h ^?1(D), then if T satisfies the property “every regular Gaussian polynomial has locally principal content,” then also R verifies the same property. We also show that if D is a Prüfer domain and T satisfies the property “every Gaussian polynomial has locally principal content”, then R satisfies the same property. The article includes a brief discussion of the scopes and limits of our result.     

Anti-Substitution Intuitions and the Content of Belief Reports

Philosophers of language traditionally take it that anti-substitution intuitions teach us about the content of belief reports. Jennifer Saul [1997, 2002 (with David Braun), 2007] challenges this lesson. Here I offer a response to Saul’s challenge. In the first two sections of the article, I present a common sense justification for drawing conclusions about content from anti-substitution intuitions. Then, in Sect. 3, I outline Saul’s challenge—what she calls ‘the Enlightenment Problem’. Finally, in Sect. 4, I argue that Saul’s challenge does not undermine the common sense justification presented in Sects. 1 and 2. I avoid the challenge by arguing that anti-substitution intuitions are not directly sensitive to the content of the sentences that produce them, but rather to the possibility that one could have distinct ways of thinking about an object.     

Disbelieving the Normativity of Content

Adherents as well as detractors of the normativity of mental content agree that its assessment crucially depends on the assessment of a principle for believing what is true. In this paper, I present an alternative principle, which is based on possession conditions for pure thinking or mere entertaining. I argue that the alternative approach has not been sufficiently emphasised in the literature and has two important merits. First, it yields a direct analysis of the normativity of mental content, which is, furthermore, independent of arguably non-normative notions such as truth. Second, the approach suggests new and challenging lines of response to central non-normativist objections.