Capacity analysis of dual-hop wireless communication systems over α–μ fading channels

In this paper, we consider a dual hop wireless communication system with a non-regenerative relay and study its performance over the α–μ fading channel. Specifically, we derive closed-form expressions for the moment generating function (MGF), the cumulative distribution function (CDF), and the probability density function (PDF) of the harmonic mean of the end-to-end signal-to-noise ratio (SNR) assuming the α–μ fading model. We also derive closed-form expressions for the end-to-end capacity and outage capacity of the system herein. The obtained expressions can be reduced to study the performance of dual hop communication systems over other fading channel models by using the proper values for the α and μ parameters, such as Rayleigh, Nakagami-m, and Weibull fading models. Numerical results are provided for the obtained expressions and conclusion remarks are drawn.     

基于(α, λ)联系度容差关系的变精度粗糙集模型

基于传统粗糙集理论的方法不能有效地处理含噪音的不完备信息系统. 根据集对分析理论, 提出(α, λ)联系度容差关系. 将(α, λ)联系度容差关系与Ziarko提出的多数包含关系相结合, 提出变精度(α, λ)联系度粗糙集模型. 给出了该模型下基于正域相似度的启发式属性约简算法, 分析了算法的时间复杂度, 通过仿真实验验证了所提方法处理含噪音的不完备信息系统的有效性.     

Precise Coulomb wave functions for a wide range of complex ?, η and z

A new algorithm to calculate Coulomb wave functions with all of its arguments complex is proposed. For that purpose, standard methods such as continued fractions and power/asymptotic series are combined with direct integrations of the Schrödinger equation in order to provide very stable calculations, even for large values of |η| or |ℑ(?)|. Moreover, a simple analytic continuation for is introduced, so that this zone of the complex z-plane does not pose any problem. This code is particularly well suited for low-energy calculations and the calculation of resonances with extremely small widths. Numerical instabilities appear, however, when both |η| and |ℑ(?)| are large and comparable or smaller than |ℑ(?)|.

Program summary

Title of program: cwfcomplexCatalogue number:ADYO_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYO_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandLicensing provisions: noneComputers on which the program has been tested: DELL GX400Operating systems: Linux, WindowsProgramming language used: C++No. of bits in a word: 64No. of processors used: 1Has the code been vectorized?: noNo. of bytes in distributed program, including test data, etc.: 33 092No. of lines in distributed program, including test data, etc.: 3210Distribution format:tar.gzNature of physical problem: The calculation of Coulomb wave functions with all of their arguments complex is revisited. The new methods introduced allow to greatly augment the range of accessible ?, η, and z.Method of solution: Power/asymptotic series and continued fractions are supplemented with direct integrations of the Coulomb Schrödinger equation. Analytic continuation for is also precisely computed using linear combinations of the functions provided by standard methods, which do not follow the branch cut requirements demanded for Coulomb wave functions.Typical running time: N/AUnusual features of the program: none     

Characterizations of regular ordered semigroups in terms of (α, β)-fuzzy generalized bi-ideals

In this paper, the concept of an (α, β)-fuzzy generalized bi-ideal in an ordered semigroup is introduced, which is a generalization of the concept of a fuzzy generalized bi-ideal in an ordered semigroup. Using this concept, some characterization theorems are provided. The upper/lower parts of an (∈, ∈ ∨ q)-fuzzy generalized bi-ideal are introduced and some characterizations of regular ordered semigroups are given. Also, we consider the concept of implication-based fuzzy generalized bi-ideals in an ordered semigroup. In particular, the implication operators in Lukasiewicz system of continuous-valued logic are discussed.     

On the performance analysis of SIR-based SSC diversity over correlated α-μ fading channels

In this paper, an approach to the performance analysis of dual-branch switch-and-stay combining (SSC) diversity receiver, operating over correlated α-μ fading channels in the presence of co-channel interference (CCI), is presented. Very useful novel infinite series expressions are obtained for the probability density function (PDF) and cumulative distribution function (CDF) of the SSC output signal-to-interference ratio (SIR). Capitalizing on these, performance analysis is performed based on standard criterion measures, such as the outage probability (OP) and average bit error probability (ABEP). Obtained results are graphically presented to show the effects of various parameters such as the fading severity, propagation environment non-linearity and level of correlation on the overall system’s performance.     

Approximating the Poisson Scan and (λ–σ) acoustic detection model with a Random Search formula

In this study, we develop a MATLAB simulation of area search with acoustic sensors modeled by the Poisson Scan model and the Lambda–Sigma (λ–σ) model. Detection time results are compared to those given by the much simpler Random Search formula. Random Search was found to closely approximate the more complex models if detection range was selected correctly. Guidelines for selecting the Random Search detection range were developed.     

A simpler linear time 2/3−ε approximation for maximum weight matching

We present two approximation algorithms for the maximum weight matching problem that run in time . We give a simple and practical randomized algorithm and a somewhat more complicated deterministic algorithm. Both algorithms are exponentially faster in terms of ε than a recent algorithm by Drake and Hougardy. We also show that our algorithms can be generalized to find a 1−ε approximation to the maximum weight matching, for any ε>0.     

The general α-decomposition problem of fuzzy relations

This paper deals with a general α-decomposition problem of fuzzy relations, which can be stated as follows: given a fuzzy relation R∈F(X×Y), determine two fuzzy relations Q∈F(X×Z) and T∈F(Z×Y) such that , where X (resp. Y) is a finite set. Firstly we point out that every fuzzy relation R is always generally α-decomposable, and give an algorithm to construct Q and T with for a given R. Secondly, we show that the general content ρ(R) with is equal to the chromatic number of the simple graph F_R generated by R. Therefore, finding an exact algorithm for calculating ρ(R) is an NP-complete problem.     

A ν-twin support vector machine (ν-TSVM) classifier and its geometric algorithms

In this paper, a ν-twin support vector machine (ν-TSVM) is presented, improving upon the recently proposed twin support vector machine (TSVM). This ν-TSVM introduces a pair of parameters (ν) to control the bounds of the fractions of the support vectors and the error margins. The theoretical analysis shows that this ν-TSVM can be interpreted as a pair of minimum generalized Mahalanobis-norm problems on two reduced convex hulls (RCHs). Based on the well-known Gilbert’s algorithm, a geometric algorithm for TSVM (GA-TSVM) and its probabilistic speed-up version, named PGA-TSVM, are presented. Computational results on several synthetic as well as benchmark datasets demonstrate the significant advantages of the proposed algorithms in terms of both computation complexity and classification accuracy.     

Fuzzy ε-subgroups

The aim of the paper is to investigate the known classical problem of a partition of a semigroup into a family of groups in the lattice-valued (fuzzy) framework. For that purpose, a fuzzy subgroup of a fuzzy subsemigroup is introduced and characterized by cuts, using the cutworthy approach. As a main result it is proved that a fuzzy subsemigroup can be partitioned (using special type of fuzzy partitions) into a family of fuzzy ε-subgroups if and only if it is fuzzy completely regular.     

Studies of angular correlations in the decays Bs→J/ψφ by using the SIMUB generator

The performance of the method of angular moments on the ΔΓ_s determination from analysis of untagged decays is examined by using the SIMUB generator. The results of Monte Carlo studies with evaluation of measurement errors are presented. The method of angular moments gives stable results for the estimate of ΔΓ_s and is found to be an efficient and flexible tool for the quantitative investigation of the B⁰_s→J/ψφ decay. The statistical error of the ratio ΔΓ_s/Γ_s for values of this ratio in the interval [0.03,0.3] was found to be independent on this value, being 0.015 for 10⁵ events.     

三次均匀B样条与α-B样条的扩展

样条曲线曲面在CAD和计算机图形学领域起着重要作用. 本文提出了三次均匀B样条的几类扩展形式. 基于新的样条函数和奇异混合技术, 提出了插值 α-B样条的几类新扩展. 所提出的新样条曲线的优势是他们同时具有全局形状参数和局部形状参数. 最后进一步探讨了它们在数据点插值和多边形形状变形中的应用.     

不确定数据的最优?? 近邻和局部密度聚类算法

传统聚类算法一般针对的是确定数据, 无法解决不确定数据的聚类问题; 现有基于密度的不确定数据聚类算法存在参数敏感且计算率低的问题. 对此, 在引进新的不确定数据相异度函数、最优?? 近邻、局部密度和互包含概念的基础上, 提出解决不确定数据聚类问题的不确定数据的最优?? 近邻和局部密度聚类(OLUC) 算法. 该算法不仅能降低参数敏感性, 提高计算效率, 而且具有动态自适应优化?? 近邻, 快速发现聚类中心和除噪优化的能力. 实验结果表明, 所提出的算法对无论是否存在噪声的不确定数据集都效果良好.

     

Determination of α-resolution in lattice-valued first-order logic LF(X)

Key issues for resolution-based automated reasoning in lattice-valued first-order logic LF(X) are investigated with truth-values in a lattice-valued logical algebraic structure-lattice implication algebra (LIA). The determination of resolution at a certain truth-value level (called α-resolution) in LF(X) is proved to be equivalently transformed into the determination of α-resolution in lattice-valued propositional logic LP(X) based on LIA. The determination of α-resolution of any quasi-regular generalized literals and constants under various cases in LP(X) is further analyzed, specified, and subsequently verified. Hence the determination of α-resolution in LF(X) can be accordingly solved to a very broad extent, which not only lays a foundation for the practical implementation of automated reasoning algorithms in LF(X), but also provides a key support for α-resolution-based automated reasoning approaches and algorithms in LIA based linguistic truth-valued logics.     

Vertex fault tolerance of optimal-κ graphs and super-κ graphs

A connected graph G is optimal-κ if κ(G)=δ(G). It is super-κ if every minimum vertex cut isolates a vertex. An optimal-κ graph G is m-optimal-κ if for any vertex set S⊆V(G) with |S|?m, G−S is still optimal-κ. We define the vertex fault tolerance with respect to optimal-κ, denoted by Oκ(G), as the maximum integer m such that G is m-optimal-κ. The concept of vertex fault tolerance with respect to super-κ, denoted by Sκ(G), is defined in a similar way. In this paper, we show that min{κ₁(G)−δ(G),δ(G)−1}?Oκ(G)?δ(G)−1 and min{κ₁(G)−δ(G)−1,δ(G)−1}?Sκ(G)?δ(G)−1, where κ₁(G) is the 1-extra connectivity of G. Furthermore, when the graph is triangle free, more refined lower bound can be derived for Oκ(G).     

An information-theoretic characterization of weighted α-proportional fairness in network resource allocation

This paper provides a characterization of fairness concepts in network resource allocation problems from the viewpoint of information theory. The fundamental idea underlying this paper is to characterize the utility functions in optimization problems, which motivate fairness concepts, based on a trade-off between user and network satisfaction. User satisfaction is evaluated using information divergence measures, which were originally used in information theory, to evaluate the difference between an implemented resource allocation and a requested resource allocation. The requested resource allocation is assumed to be ideal in some sense from the user’s point of view. Network satisfaction is evaluated based on the efficiency of resource usage in the implemented resource allocation. The results in this paper indicate that the well-known fairness concept called weighted α-proportional fairness can be characterized using the α-divergence measure, which is a general class of information divergence measures, as an equilibrium of the trade-off. Some typical examples of applications demonstrate how the presented characterization works.     

A saturation method for the modal μ-calculus over pushdown systems

We present an algorithm for computing directly the denotation of a μ-calculus formula χ over the configuration graph of a pushdown system. Our method gives the first extension of the saturation technique to the full μ-calculus. Finite word automata are used to represent sets of pushdown configurations. Starting from an initial automaton, we perform a series of automaton manipulations which compute the denotation by recursion over the structure of the formula. We introduce notions of under-approximation (soundness) and over-approximation (completeness) that apply to automaton transitions rather than runs. Our algorithm is relatively simple and direct, and avoids an immediate exponential blow up. Finally, we show experimentally that the direct algorithm is more efficient than via a reduction to parity games.     

A simple proof of the necessity of the failure detector Σ to implement an atomic register in asynchronous message-passing systems

This paper presents a simple proof that shows that the quorum failure detector class (denoted Σ) is the weakest failure detector class required to implement an atomic read/write register in an asynchronous message-passing system prone to an arbitrary number of process crashes. This proof is based on a new reduction algorithm in which all the variables are bounded.