A new numerical method for kinetic equations in several dimensions

We present first results of a numerical method solving inhomogeneous partial differential equation of first order with a conservation property. The method is based on the Finite Particle Schemes for homogeneous PDE's of the first order as the Vlasov-Poisson system in kinetic theory. The inhomogeneity is redefined as a flux. For the associated ‘velocity-field’ given by the Radon-Nikodym derivative of the flux, we give a numerical approximation. Together with the ‘velocity-field’ given, by the derivative terms of first order this gives the right hand side of the equations of motion of the particles. The computation can be done in a very efficient way and the results are in good agreement with the exact solution.     

A new method for computing the reaction between two rooftop basis functions in a planar structure

Accurate and efficient techniques are developed for computing spectral domain reaction integrals involving rooftop basis functions. Representing the angular integral in terms of special functions not only reduces the two-dimensional integration by one dimension, but it also leads to the development of a novel asymptotic extraction technique.     

A new method for using hash functions to solve remote user authentication

Recently, Peyravian and Zunic proposed the remote password authentication schemes only based on the collision-resistant hash function. The schemes are, therefore, easy to implement and simple to use. The attractive properties cause a series of discussion. Several security flaws are found and remedied. Unfortunately, most of the remedies either are insecure or violate the original advantages because of involving public-key cryptosystems or modular exponential operations. Hence, it is still a challenge to design a secure scheme abiding by the beneficial assumption of the Peyravian-Zunic schemes. The proposed scheme not only keeps the original advantages (user friendness and computational cheapness) but also highlights certain of valuable features, such as (1) mutual authentication (higher security level), (2) server’s ignorance of users’ passwords (further security guaranee to users, specially for financial services), (3) immunity from maintaining security-sensitive table (maintaining burden reduction to servers), and so forth.     

A new and effective hierarchical overlay structure for Peer-to-Peer networks

The tremendous growth of public interest in Peer-to-Peer (P2P) networks in recent years has initiated a lot of research work on how to design efficient overlay structures for P2P systems. Scalable overlay networks such as Chord, CAN, Pastry, and Tapestry provide no control over where data is stored and the location of the peers and resources is determined by the hash values of their identifiers and keys respectively. As a result, these overlays cannot support range queries and other proximity-aware complex queries directly.In this paper, we present a hierarchical P2P overlay network called SkipCluster, which is capable of supporting both exact-match and multi-dimensional range queries efficiently without consumption of extra memory space. SkipCluster is derived from skip graphs and SkipNet, but it has a two-tier hierarchical architecture.In both tiers, peers are connected in sequence according to the order of their peer IDs, and related resources are stored near each other without hashing of their resource keys. We design a novel data structure called Triple Linked List (TLL) to store each super-peer’s pointers in the higher tier, which can be used to find the longest prefix and speed up query routing of inter-cluster. In the lower tier, each intra-cluster peer’s routing table contains pointers with exponentially incremental distance. Experimental results show that SkipCluster can speed up both exact-match and range queries in different network sizes.     

计算机课程教学中有效提问探究

有效提问是有效教学的一个重要组成部分,好的提问不仅可以激发学生的学习兴趣,而且更能引导学生的思维动向.在职业学校计算机课程教学中,又该如何灵活地运用提问来提高课堂教学的有效性呢？本文将从课堂提问的目的,课堂提问的艺术和课堂提问的注意点三个方面来加以论述.     

一种新型的滑模变结构增益调度控制器设计方法

研究影响一般滑动模态变结构控制性能的因素,并给出了根据切换函数选择滑动模态系数、边界层厚度以及控制器增益系数的一般要求．针对一类含参数不确定性的非线性系统,采用新型增益调度变结构控制策略进行控制,以切换函数作为调度变量对滑动模态系数、边界层厚度以及控制器增益系数进行调度,以提高滑动模态变结构控制系统的控制性能,抑制颤振,降低控制能耗．仿真算例验证了所提出控制策略的有效性．     

A new method for implementing moment functions in a CMOS retina

We present in this paper a new method for implementing geometric moment functions in a CMOS retina. The principle is based on the similarity between geometric moment equations and the measurement of the correlation value between an image to analyze and a range of grey levels. The latter is approximated by a binary image called mask using a dithering algorithm in order to reduce hardware implementation cost. The correlation product between the mask and the image under analysis gives an approximated value of the geometric moment with an error less than 1% of the exact value. Finally, the results obtained by our approach have been applied to an object localization application and the localization error due to the approximated moment values reported. Olivier Aubreton was born in Vichy on August 31, 1973. He obtained the agrégation examination in June 2000 and received the D.E.A. degree (equivalent to a master degree) in image processing in June 2001. He is currently a lecturer working towards a Ph. D. degree at Laboratory LE2I in the IUT of Le Creusot in Burgundy. His research interests include the design, development implementation, and testing of silicon retinas for pattern matching and pattern recognition. Lew F.C. Lew Yan Voon received his Ph.D. degree in Computer Aided Design of VLSI circuits from Montpellier University, France, in March 1992. Since September 1993, he has been first assistant professor and then associate professor at the University of Burgundy. His research interests lie in the field of pattern recognition and in the design of silicon retinas in standard CMOS technology for real-time inspection by machine vision. Bernard Lamalle was born in Autun on May 1, 1946. He obtained the Ph.D. degree in 1973 from the Université de Bourgogne in Dijon. During 1980 to 2000 he has been Maître de conférences at the IUT of Le Creusot in Bourgogne. He joined the image processing team of laboratory Le2i in 1992. Since 2000, he has been appointed full professor of the University of Bourgogne. His field of interest is principally the study and design of silicon retinas dedicated to industrial control. He has in charge some industrial contracts in the field of quality control by artificial vision and he holds two patents in the field of image processing and smart sensors. Guy Cathébras was born in Uzès, France, in 1961. He received the French engineer degree from the Ecole Nationale Supérieure de l'Electronique et de ses Applications, Cergy, France, in 1984 and the Diplôme de Doctorat de l'Université de Montpellier, France, in 1990. Since 1992 he is an assistant professor of microelectronics at the Institut des Sciences de l'Ingénieur de Montpellier. His current research interests include the design of imagers and silicon retinas using standard CMOS technologies.     

A new method for constructing membership functions and fuzzy rulesfrom training examples

To extract knowledge from a set of numerical data and build up a rule-based system is an important research topic in knowledge acquisition and expert systems. In recent years, many fuzzy systems that automatically generate fuzzy rules from numerical data have been proposed. In this paper, we propose a new fuzzy learning algorithm based on the alpha-cuts of equivalence relations and the alpha-cuts of fuzzy sets to construct the membership functions of the input variables and the output variables of fuzzy rules and to induce the fuzzy rules from the numerical training data set. Based on the proposed fuzzy learning algorithm, we also implemented a program on a Pentium PC using the MATLAB development tool to deal with the Iris data classification problem. The experimental results show that the proposed fuzzy learning algorithm has a higher average classification ratio and can generate fewer rules than the existing algorithm.     

A new approach to estimate fractal dimensions of corrosion images

A new approach is proposed based on box-counting method to estimate the fractal dimensions, D_2d and D_3d of corrosion images. They denote two-dimensional (2D) and three-dimensional (3D) characteristics of corroded surface morphology. The results have been tested through dealing with classical fractal figures, pit morphology of moon surface and practical corroded samples etc. to show that this new method is computationally simple, convenient and accurate. More specially, D_2d and D_3d have definite corrosion expressions, which respectively denote the fractal dimensions for pit diameter distribution and pit depth distribution on real corroded surface.     

A robust method for the computation of new closed‐form Green's functions for microstrip structures

A robust approach for the computation of new closed‐form Green's functions is considered to calculate the symmetrical microstrip Green's functions. In this method, the surface‐wave poles are first extracted using a recursive contour integration method. Then, the remainder is approximated by a series of complex exponentials using the Prony's method or the generalized pencil‐of‐function method (GPOF) along the extended rooftop shaped path in k_ρ‐plane. Subsequently, an analytical identity is employed to obtain the new spatial‐domain Green's functions. It is observed that this method can evaluate the spatial‐domain Green's functions accurately and efficiently for both near and far fields. In addition, there is no erroneous results in the near‐field region when z ≠ z′ and ρ → 0. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

A new uncertainty propagation method considering multimodal probability density functions

Structural and Multidisciplinary Optimization - In practical engineering applications, random variables may follow multimodal distributions with multiple modes in the probability density functions,...     

A minimization method for boolean functions

Algorithms are proposed for constructing one and all prime implicants covering a given point, a DNF consisting of prime implicants, and a reduced DNF. The complexity of the proposed algorithms is investigated.Translted from Kibernetika, No. 5, pp. 44–48, September–October, 1989.     

Opening new dimensions for e-Tourism

In this paper we describe an e-Tourism environment that takes a community-driven approach to foster a lively society of travelers who exchange travel experiences, recommend tourism destinations or just listen to catch some interesting gossip. Moreover, business transactions such as booking a trip or getting assistance from travel advisors or community members are constituent parts of this environment. All these happen in an integrated, game-like e-Business application where each e-Tourist is impersonated as an avatar. More precisely, we apply 3D Electronic Institutions, a framework developed and employed in the area of multi-agent systems, to the tourism domain. The system interface is realized by means of a 3D game engine that provides sophisticated 3D visualization and enables humans to interact with the environment. We present “itchy feet”, a prototype implementing this 3D e-Tourism environment to showcase first visual impressions. This new environment is a perfect research playground for examining heterogeneous societies comprising humans and software agents, and their relationship in e-Tourism.     

A structure theorem for the elementary functions and its application to the identity problem

This paper uses elementary algebraic methods to obtain new proofs for theorems on algebraic relationships between the logarithmic and exponential functions. The main result is a multivariate version of a special case of the structure theorem due to Risch that gives, in a very explicit fashion, the possible algebraic relationships between the exponential and logarithm functions. The structure theorem has important applications to symbolic mathematical computation in that it in essence provides a canonical form for the elementary transcendental functions, and hence solves the identity problem for this class of functions. Such applications are discussed in the last section.This research was supported in part by National Science Foundation Grants GJ-30125X and MCS76-23762.     

一种新型TD-SCDMA帧结构参数设计方法

提出一种新型的基于正交频分复用(OFDM)技术的TD-SCDMA系统帧结构参数设计方法,其既能与已有3G系统共存,又具有更高的系统容量和频谱利用率。     

A new radial basis functions method for pricing American options under Merton's jump-diffusion model

A new radial basis functions (RBFs) algorithm for pricing financial options under Merton's jump-diffusion model is described. The method is based on a differential quadrature approach, that allows the implementation of the boundary conditions in an efficient way. The semi-discrete equations obtained after approximation of the spatial derivatives, using RBFs based on differential quadrature are solved, using an exponential time integration scheme and we provide several numerical tests which show the superiority of this method over the popular Crank–Nicolson method. Various numerical results for the pricing of European, American and barrier options are given to illustrate the efficiency and accuracy of this new algorithm. We also show that the option Greeks such as the Delta and Gamma sensitivity measures are efficiently computed to high accuracy.