量子信息研究进展

量子信息论是经典信息论与量子力学相结合的新兴交叉学科,本综述了最子信息领域的研究进展。即包括了为人们所熟知的量子通信与量子计算领域,也包括了刚刚兴起的但却有巨大潜力的量子对策论等领域。本以介绍量子信息论的基本理论框架为主,同时也介绍了量子信息领域的实验研究进展。     

粗交流结果最优传递序列的模拟退火算法

粗交流中,确定概念在多个agents间传递时,由于各个agent有不同的语言,相互之间不能提供准确的信息交流,从而导致概念在传递过程中会丢失部分信息,最后得到粗糙的结果。在不同的粗交流传递序列中,信息的丢失量往往是不同的。利用模拟退火算法,得到使参与粗交流的最后一个agent获得信息量最大的粗交流传递序列。算法的分析和仿真验证了该方法的有效性。     

Explicit exponential lower bounds for exact hyperplane covers

We describe an explicit and simple subset of the discrete hypercube which cannot be exactly covered by fewer than exponentially many hyperplanes. The proof exploits a connection to communication complexity, and relies heavily on Razborov's lower bound for disjointness.     

A scaling analysis of a star network with logarithmic weights

The paper investigates the properties of a class of resource allocation algorithms for communication networks: if a node of this network has $L$ requests to transmit and is idle, it tries to access the channel at a rate proportional to $log(1+L)$. A stochastic model of such an algorithm is investigated in the case of the star network, in which $J$ nodes can transmit simultaneously, but interfere with a central node 0 in such a way that node 0 cannot transmit while one of the other nodes does. One studies the impact of the log policy on these $J+1$ interacting communication nodes. A fluid scaling analysis of the network is derived with the scaling parameter $N$ being the norm of the initial state. It is shown that the asymptotic fluid behavior of the system is a consequence of the evolution of the state of the network on a specific time scale $(N^t,t\in (0,1))$. The main result is that, on this time scale and under appropriate conditions, the state of a node with index $j\ge 1$ is of the order of $N^{a_j\left(t\right)}$, with $0\le a_j\left(t\right)<1$, where $t?a_j\left(t\right)$ is a piecewise linear function. Convergence results on the fluid time scale and a stability property are derived as a consequence of this study.     

Analyzing students’ communication and representation of mathematical fluency during group tasks

Findings discussed in this paper are from a larger research project exploring mathematical fluency characteristics, and teacher noticing and interpreting of mathematical fluency. The current study involved students from seven primary classes (Kindergarten – Grade 6, N = 63 students) and investigated students’ written work samples and oral discussions as they collaborated in small groups to solve mathematical tasks. Students displayed mathematical fluency both orally and in written/drawn form. Certain aspects of mathematical fluency were easier to identify orally (adaptive reasoning) particularly for younger students and when students did not provide any written reasoning. Analyzing the oral responses was often needed to identify mathematical fluency beyond knowledge of a correct procedure (strategic competence). Findings suggested that the various representations students used were valuable for observing mathematical fluency. These results suggest that oral assessments as a means to understand and interpret students’ mathematical fluency are necessary.     

大气信道紫外光通信系统通信距离的增程方法

介绍了紫外光大气传输理论和非直视单散射模型.在此模型基础上,针对紫外光通信系统的结构设计对信道能量损耗的影响进行了理论上的定性分析.对不同天气、不同通信模式、不同几何结构参量条件下,大气信道所产生的能量损耗进行了定量仿真.仿真结果表明:能量衰减随通信距离的增加而增大;不同能见度条件下,能量衰减随通信距离的递增程度不同,能见度越高能量衰减越小,可实现的通信距离越远;通信距离随发射仰角的减小而增加,随接收仰角的减小而增加,且发射仰角对通信距离的影响程度大于接收仰角;通信距离随发射束散角的增加而增加,随接收视场角的减小而增加,且接收视场角对通信距离的影响程度远大于发射束散角.     

Comparing multi-dimensional contingency fit to financial performance of organizations

In theory, it is widely accepted that an organization’s optimal structure is contingent upon various situational factors such as market conditions, nature of work and properties of technology. In practice, providing practical advice based on this understanding has been difficult. This paper demonstrates that it is possible to find a correlation between financial performance, as measured by growth in Return on Assets, and degree of compliance with the recommendations of the contingency theory model known as Interaction Value Analysis (IVA). IVA is based on an abstract theoretical representation of organizational work as a series of value-adding interactions among rational value-maximizing agents. Six different dimensions of an organization’s situation are represented as parameters of the equation that sums up the value added by all interactions within the organization. This “Multi-dimensional” approach is contrasted with the “Multi-contingency” model, which aggregates the effects of multiple contingent-design rules without considering how the rules overlap or otherwise influence one another. The success of the six-parameter IVA model in partially predicting financial performance is an inducement to expand IVA to include more of the parameters included in the Multi-contingency model.     

A cross entropy approach to design of reliable networks

One of the most important parameters determining the performance of communication networks is network reliability. The network reliability strongly depends on not only topological layout of the communication networks but also reliability and availability of the communication facilities. The selection of optimal network topology is an NP-hard problem so that computation time of enumeration-based methods grows exponentially with network size. This paper presents a new solution approach based on cross-entropy method, called NCE, to design of communication networks. The design problem is to find a network topology with minimum cost such that all-terminal reliability is not less than a given level of reliability. To investigate the effectiveness of the proposed NCE, comparisons with other heuristic approaches given in the literature for the design problem are carried out in a three-stage experimental study. Computational results show that NCE is an effective heuristic approach to design of reliable networks.     

Architectural Considerations of Fiber-Radio Millimeter-Wave Wireless Access Systems

The architecture of fiber-radio mm-wave wireless access systems critically depends upon the optical mm-wave generation and transport techniques. Four optical mm-wave generation and transport techniques: 1) optical self-heterodyning, 2) external modulation, 3) up- and downconversion, and 4) optical transceiver, will be assessed. From the technical viewpoints, their advantages and disadvantages are discussed. The economical assessment, focusing on the cost of a base station BS ( ), will suggest that the optical transceiver looks the most promising in the long run, but in the near future, however, the external modulation will be cost-effective. The experimental results of 60 GHz testbeds using the external modulation will support the conclusion.