A methodology for developing Bayesian networks: An application to information technology (IT) implementation

Bayesian Networks (BNs) are probabilistic inference engines that support reasoning under uncertainty. This article presents a methodology for building an information technology (IT) implementation BN from client–server survey data. The article also demonstrates how to use the BN to predict the attainment of IT benefits, given specific implementation characteristics (e.g., application complexity) and activities (e.g., reengineering). The BN is an outcome of a machine learning process that finds the network’s structure and its associated parameters, which best fit the data. The article will be of interest to academicians who want to learn more about building BNs from real data and practitioners who are interested in IT implementation models that make probabilistic statements about certain implementation decisions.     

Real-time calculation of current optimal feedbacks for a delay system

A linear optimal control problem for a nonstationary system with a single delay state variable is examined. A fast implementation of the dual method is proposed in which a key role is played by a quasi-reduction of the fundamental matrices of solutions to the homogeneous part of the delay models under analysis. As a result, an iteration step of the dual method involves only the integration of auxiliary systems of ordinary differential equations over short time intervals. A real-time algorithm is described for calculating optimal feedback controls. The results are illustrated by the optimal control problem for a second-order stationary system with a fixed delay.     

Quantum entanglement in an oscillating macroscopic mirror

In this paper, we revisit the problem of quantum entanglement in an oscillating macroscopic mirror previously studied by Marshall et al. consisting of a modified Michelson interferometer where one of the mirrors is free to oscillate about its center of mass. A photon incident upon the oscillating mirror becomes entangled with the mirror, driving the mirror into a superposition of quantum states. Once the photon and mirror decouple, the mirror returns to its initial state. The purpose of our investigations was to optimize the parameter regime, taking into consideration the current state of technology and the demands imposed by the need to maintain a stable environment in the presence of thermal noise. Optimization should not demand ultra-low temperatures and this is reflected in our results. Our results also show that if the separation between states is maintained at 10^-14 m, the mirror size is reduced, making it easier to induce superposition in the mirror. The critical nature of mirror reflectivity and its connection to cavity decay rate was also revealed by our investigations. The results obtained through our investigations could be useful in quantum error correction, where decoherence negatively affects the results of computations performed by quantum computers. Finally, we note that we are only concerned with an isolated system, where no losses to the external environment occur and any decoherence that occurs within the system remains internal to the system; that is, any mention of decoherence refers specifically to recoverable decoherence.     

An asymptotic-numerical analysis for the lower bound dynamic buckling estimates

A finite element asymptotic analysis for determining the lower bound dynamic buckling estimates of imperfection-sensitive structures under step load of infinite duration is presented. The lower bound dynamic buckling loads and the corresponding displacements are sought in the form of asymptotic expansions based on the static stability criterion and they can be determined by solving numerically (FEM) several linear problems with a single nonsingular sub-stiffness matrix. The project supported by the State Education Commission of China     

Efficient Hardware Implementation of Finite Fields with Applications to Cryptography

The paper presents a survey of most common hardware architectures for finite field arithmetic especially suitable for cryptographic applications. We discuss architectures for three types of finite fields and their special versions popularly used in cryptography: binary fields, prime fields and extension fields. We summarize algorithms and hardware architectures for finite field multiplication, squaring, addition/subtraction, and inversion for each of these fields. Since implementations in hardware can either focus on high-speed or on area-time efficiency, a careful choice of the appropriate set of architectures has to be made depending on the performance requirements and available area.     

一种基于SNMP代理发现机制的三层拓扑发现方法

提出了一种基于SNMP代理发现机制的三层拓扑发现方法，以发现路由器和子网之间的连接关系．该方法包含代理发现、拓扑信息探测、拓扑信息分析3大步骤．给出了代理发现、信息探测的方法及策略，以及拓扑分析算法．分析了3个关键问题并给出了相应的解决方案，即：利用非路由器代理以提高探测结果完整性；利用别名发现等策略剔除冗余信息并提高探测效率；给出了内网和外网定界的策略以提高探测结果的完整性和有效性．针对实际网络的探测结果表明，该方法能够完整准确地发现远程网络的三层拓扑．     

An electronical system for real-time measurement of the logarithmic magnitude of scattering parameters

An electronical system for real-time measurement of scattering parameters of millimeterwave two-ports is described. In order to achieve a suitable measurement accuracy, the output signals of the millimeterwave detectors and the characteristic of the measurement amplifier should be matched. For this reason the detector power-characteristic is approximated by help of a polygon and it is realized with a few nonlinear amplifiers. The theoretical background and experimental results show the applicability of the measurement system presented here.     

凹角型区域椭圆边值问题的自然边界归化

In this paper, the natural boundary reduction for some elliptic boundary value problems with concave angle domains and their natural boundary methods are investigated. The natural integral equations and the Poisson integral formulae are given. The finite element methods of the natural integral equations are discussed in details. The convergences of the approximate solutions and their error estimates are obtained. Finally, some numerical examples are presented to show that our methods are effective.     

双极双向联想存储器的单通道光学实现

以附加神经元引入附加背景的方式获得将线性离散比极神经元的神经网络在单通道光学矢量-矩阵乘法器内实现的方法,给出了相应的光学系统的修正和非负光学模板的编码形式.以双极神经元的双向联想存储器为例进行了计算机和光电实验模拟.