二值命题逻辑公式的语构程度化方法

本文从语构理论入手,在经典二值命题逻辑系统中给出公式的语构真度的概念,从两个不同的角度给出语构真度的等价刻画.给出语构真度的实例,说明原来在语义下的真度是语构真度,并且由语构真度诱导的相似度和伪距离具有语义下相似度和伪距离的基本性质.给出τ-相容理论的概念,指出τ-相容理论和相容理论的内在关系.     

The Role of Network Topologies in the Optical Core of IP-over-WDM Networks with Static Wavelength Routing

In this paper, we present a performance analysis of network topologies for the optical core of IP-over-WDM networks with static wavelength routing. The performance analysis is focused on regular degree four topologies, and, for comparison purposes, degree three topologies are also considered. It is shown that the increase of the nodal degree from three (degree three topology with smallest diameter) to four (degree four topology with smallest diameter) improves the network performance if a larger number of wavelengths per link is available. However, the influence of wavelength interchange on the nodal degree gain is small. The performance of regular degree four topologies with smallest diameter is also compared with the performance of mesh–torus topologies (which are also degree four topologies), and it is shown that the blocking probability of degree four topologies with smallest diameter is about two orders of magnitude lower than the blocking probability of mesh–torus topologies. It is also presented a performance comparison of WDM-based networks with nodal degrees ranging from two to five and it is shown that the increase of the nodal degree from two to three leads to high nodal degree gains, while de increase of the nodal degree from four to five leads to low nodal degree gains. These results show that degree three and degree four topologies are very attractive for use in the optical core of IP-over-WDM networks.     

Effects of the Degree of Cure on the Electrical and Mechanical Behavior of Anisotropic Conductive Films

In this work, the effects of the degree of cure on the electrical and mechanical behavior of an anisotropic conductive film (ACF) were investigated. The degree of cure of the ACF as a function of bonding time was quantified by dynamic differential scanning calorimetry (DSC) study and attenuated total reflectance/Fourier-transform infrared (ATR/FT-IR) analysis. According to the results, the thickness expansion rate of the ACF as a function of temperature decreased and the storage modulus increased as the degree of cure increased. In addition, the contraction stress of a partially cured ACF with a degree of cure below 40% was much smaller than that of an ACF with a degree of cure above 90%. The ACF contact resistance decreased and the ACF peel adhesion strength increased as the degree of cure of the ACF increased. In particular, poor electrical contact was observed when the degree of cure was below 40%. The ultimate tensile strength (UTS) increased as the degree of cure increased and was closely related to the peel adhesion strength. Furthermore, ACF joints with a degree of cure below 40% had higher contact resistance than those with a degree of cure above 90% during 85°C/85% relative humidity testing.     

On the degree of completeness of cryptographic functions

This paper discusses the degree of completeness of cryptographic functions, which is one of the cryptographic criteria should be considered in the design of stream ciphers. We establish the re- lationships between the degree of completeness and other cryptographic criteria. For resilient Boolean functions, a method to enhance the degree of completeness is proposed, while the nonlinearity and the algebraic degree do not decrease. Moreover, two constructions of resilient functions are provided, which have optimal degree of completeness, high nonlinearity, and high algebraic degree.     

Use of a Luenberger observer to control the numerator and denominator of a transfer function

It is shown that a Luenberger observer may be used to convert a transfer function having a numerator of degree m and a denominator of degree n (with m?n?1) into one having a numerator of degree n+m?1 and a denominator of degree 2n?1, with the denominator polynomial and n?1 of the numerator coefficients assignable arbitrarily.     

Performance Implications of Meshing Degree for Optical Burst Switched Networks Using One-Way Resource Reservation Protocols

This paper discusses performance implications of meshing degree (or nodal degree) for optical burst switching (OBS) mesh networks using one-way resource reservation protocols. The analysis is focused on the following topologies: rings, chordal rings with nodal degrees ranging from three to six, mesh-torus, NSFNET, ARPANET and the European Optical Network (EON). It is shown that the largest nodal degree gain, due to the increase of the nodal degree from two to around three, is observed for degree-three chordal ring topology, where as the smallest gain is observed for the ARPANET. For these cases, the magnitude of the nodal degree gain is slightly less than three orders for the degree-three chordal ring and less than one order of magnitude for the ARPANET. On the other hand, when the nodal degree increases from two to a value ranging from about four up to six, the nodal degree gain ranges between four and six orders of magnitude for chordal rings. However, EON, which has a nodal degree slightly less than four has the smallest nodal degree gain. The observed gain for this case is less than one order of magnitude. Since burst loss is a key issue in OBS networks, these results clearly show the importance of meshing degree for this kind of networks.     

一种规则变量节点度LTCodes编码方案

LT Codes差错平台(Erasure Floor)由变量节点的最小度决定,规则变量节点度LT Codes能够最大化变量节点的最小度,从而降低LT Codes的差错平台.该文提出一种新的规则变量节点度LT Codes编码方法,该编码方法省去了现有方法中对变量节点度值查找表的排序操作,降低了现有方案的编码复杂度;通过对度分布的修正增加低度校验节点,使得规则变量节点度LT Codes解码瀑布区域(雪崩区域)提前.仿真结果表明该文方法与现有方法相比有效减少了编码时间,降低了成功解码所需的平均传输开销,加快了误符号率收敛速度.     

无线传输中短码长喷泉码的度分布优化算法

数字喷泉码是针对大规模网络数据分发而提出的一种新的信道编码方式。度分布是决定数字喷泉码译码性能的关键因素。为提高译码性能,针对应用于无线信道的喷泉码提出了一种度分布优化的算法。首先,根据理想孤子分布和鲁棒孤子分布产生度值序列,然后将该度值序列截短,在此基础上根据优化算法求解该序列中每个度值的最优概率,最后得到优化的度分布。仿真结果表明,本算法产生的度分布进行编译码产生的误码率低于鲁棒孤子分布和固定度分布,提高了译码性能。     

基于边生命周期的短波IP网络随机图模型

针对短波IP网络中物理连接存在生命周期和接收节点选择方式不同对网络拓扑结构和性能产生的影响,提出了一种基于边生命周期和接收节点多种选择方式的随机图模型。模型中节点之间边生命周期服从正态分布,而新边建立的节点选择方式按照随机选择、度值择优选择和度值反择优选择的方式,用来模拟短波IP网络不同的通信过程。理论分析和仿真也发现,接收节点选择方式的不同将会对网络的度分布、平均最短距离、网络总的度值和节点最大度值及聚集系数都产生影响,而小的连接生命周期将显著减少网络中总的度值和节点的最大度值,减少对物理层资源的占用,提升网络的效能。     

An Analytical Model for the Node Degree in Wireless Ad Hoc Networks

Node degree is regarded as an important and convenient metric to measure the connectivity of wireless ad hoc networks. Existing studies are mainly based on the assumption that nodes are static and do not provide closed-form expressions for node degree. In this paper, we investigate three fundamental characteristics of a wireless ad hoc network: Its node degree distribution, its average node degree and its maximum node degree experienced by the nodes during their movement. We introduce a novel mathematical model to derive analytical expressions in the presence of radio channel fading. Furthermore, our results reveal that the node degree distribution follows a binomial distribution regardless of the initial distribution of nodes?? location. The results of this paper are useful to study node connectivity and to improve the algorithmic complexity of incentive protocols.     

高斯-谢尔模型光束通过聚焦光学系统的偏振特性

为了研究高斯-谢尔模型光束的偏振特性,采用交叉谱密度矩阵的方法,研究了该光束通过聚焦光学系统的偏振特性,得到了完全偏振和完全非偏振光束保持偏振度不变的条件,并给出了通过聚焦光学系统后传输平面偏振度实现均匀分布的条件。结果表明,聚焦光学系统中偏振度在焦点位置附近有明显的起伏变化;焦点位置上的偏振度等于其在自由空间传输时的远场稳定偏振度。该研究对激光传输领域具有重要的理论和现实意义。     

L*系统中公式的语构程度化方法

 本文从语构角度出发,给出L^*系统中公式的语构真度的概念,讨论其相关的一系列性质,并进一步研究L^*系统中由语构真度诱导的公式间的相似度及伪度量,证明由语构真度诱导的伪度量空间中运算的连续性,从而为在L^*系统中基于语构理论展开近似推理提供可能的框架.     

Link prediction method based on matching degree of resource transmission for complex network

In order to solve the problem that many existing resource-transmission-based methods ignore the important influence of the matching degree of two endpoints on resource transmission,a link prediction method was proposed based on matching degree of resource transmission for complex networks.Firstly,by analyzing the two endpoints on the resource transmission path in detail,the method of quantifying the matching degree between two nodes was proposed.Then,in order to describe the influence of matching degree on resource transmission process between nodes,the matching degree of resource transmission was defined.Finally,based on the matching degree of resource transmission,a resource transmission matching index was proposed considering the resource amount of bidirectional transmission between nodes.The experimental results of nine datasets show that compared with other similarity indices,the proposed index can achieve higher prediction accuracy under the AUC and Precision metrics.     

关于线性时间复损码的研究

本文对基于随机二部图的复损码进行了深入的研究.提出了给定度分布对的复损码成功译码时可接受最大损失δ的一上界,通过对此上界的详细分析提出了求解复损码度分布对的一种算法.这就从理论上说明了具有如上算法选取度分布对的复损码,应该优于文[2]所给度分布对的复损码.而且证明了具有某一确定度分布对的复损码能以线性时间可编码和可成功地译码.     

多值逻辑中基于Camberra模糊距离的计量化方法

本文以模糊集间的Camberra距离为工具,给出了多值Lukasiewicz逻辑系统中公式间的Camberra-距离,Camberra-相似度与Camberra-真度的概念,讨论了Camberra-相似度与Camberra-真度的性质,证明了每一个公式φ的Camberra-真度都等于一些互不相容的公式的Camberra-真度之和.然后以Camberra-真度为依托,研究了Lukasiewicz逻辑度量空间的一些性质,证明了三值Lukasiewicz逻辑度量空间没有孤立点,以及每一个球形领域都是不相容理论等结论.为在公式集F（S）上展开程度化推理提供了一种新的方法.     

Tight focusing of a partially coherent and partially polarized beam

The focusing properties of a partially coherent and partially polarized beam focused by a high numerical aperture(NA) objective are investigated.The influence of the degree of polarization and the correlation length of the incident beam and the numerical aperture of the objective on the intensity and degree of polarization in the focal region is studied.It is shown that the intensity and degree of polarization in the focal region change with the degree of polarization and the correlation length of the incid...     

非规则LDPC度分布优化设计

一对好的度分布可以有效降低LDPC的错误平层和编译码复杂度,在AWGN信道下,通过高斯近似分析方法可近似计算给定度分布的LDPC译码门限,利用差分进化算法可优化度分布以获得具有最大门限的度分布,仿真结果表明获得的度分布的译码门限比线性算法优化结果要好0.15dB左右。     

基于度分布合并和可译集优化的LT码度分布设计方案

喷泉码的度分布对喷泉码的编译码性能有着十分重要的影响.目前常用的度分布在源数据码长较长时具有较好的性能,但在码长较短时,性能有明显下降.本文给出一种LT码度分布的构造方法.该方法先对二进制度分布进行调整,然后将其与鲁棒孤子度分布进行有机结合,再通过优化可译集合值来进一步优化度分布函数,得到一种当源数据为短码长时也有较好性能的度分布,即修正二进制-鲁棒孤子度分布.仿真结果证明,采用这种度分布对源数据进行LT编码时,相比较二进制度分布和鲁棒孤子度分布,其译码性能得到了明显提高,并且码长越短,性能提高越明显.     

LT码中高效联合度分布的设计

度分布是影响数字喷泉码性能的关键因素。传统的经典度分布如理想孤子分布、鲁棒孤子分布、二进制指数分布等,由于其明显的性能缺陷,已不能满足日益增长的多媒体业务的需求。为了设计一种性能优良的度分布,提出了两种新的联合度分布设计方案。首先,将泊松分布和滑动-鲁棒孤子分布相结合,构成一个比例系数的联合度分布;然后,将泊松分布、理想孤子分布、滑动-鲁棒孤子分布这三种度分布相结合,构成两个比例系数的联合度分布;最后,通过仿真查找的方法确定两种方案中的比例系数的最优值。仿真结果表明,提出的两种新方案和已知的经典度分布、单比例系数的联合度分布相比较,在译码成功率、误码率等性能指标上都有大幅提升。     

基于IBED和仿生算法的LT码度分布设计

度分布是影响Luby变换（Luby transform,LT）码性能优劣的关键因素,为了得到更优的度分布,提出一种基于改进的二进制指数分布（improved binary exponential distribution,IBED）和仿生算法的LT码度分布设计方案.采用IBED度分布进行LT编码,初始译码成功率可高达90%以上,但随着译码开销增大,译码成功率上升速度减缓,而此时鲁棒孤子分布（robust soliton distribution,RSD）的译码性能表现更佳.为了将IBED和RSD的优点有机结合,利用人工鱼群算法（artificial fish swarm algorithm,AFSA）在两种度分布间寻优,基于期望可译集构建该算法的目标函数,通过最大化目标值得到更优的度分布.仿真结果表明,与类似方法及传统的RSD相比,采用新度分布进行LT编码可明显降低译码开销,并节约编译码耗时.