发电厂二次技术中存在问题与解决策略

在水力发电厂的运行中所包含的二次技术主要是指电气自动化技术。在技术的应用中的问题主要是自动化技术的应用和操作中的实际问题,从水力发电厂的电气自动化技术应用现状入手进行分析,进一步明确操作环节技术误差产生的问题类型和主要引发原因,是提出有效地问题解决策略的有效路径。针对问题的分析也有利于水力发电厂的工作人员及时解决个人技术应用问题,提高个人的技术应用能力。     

浅谈当前计算机网络安全应用问题及防范策略

随着互联网的应用发展,网络安全应用问题日益突出,因此如何防范计算机网络安全应用问题,将对社会经济的发展影响重大,笔者就此在本文中重点分析网络安全应用问题并归纳,针对性提出防范措施,以希望进一步提高计算机技术对社会发展的积极作用。     

SSL协议应用中安全技术问题探究

随着信息化浪潮的发展,SSL协议的应用非常普遍,但是在SSL协议应用的工程实践中也发现了一些应用模式所导致的问题,文章首先介绍了SSL协议的安全技术应用,重点分析了其中安全技术问题的表现,并通过国产密码算法与SSL协议之间应用兼容性的问题分析,提出了一些SSL协议应用模式的建议。     

Android系统内存管理研究及优化

随着基于android平台开发的应用越来越多,内存利用率问题成为应用开发者不可忽视的问题,如何让应用运行的更流畅,避免频繁的因内存不足而导致的系统崩溃问题的发生,成为应用开发者必须面对的问题.本论文试图解决这个问题.首先对android系统内部的内存管理机制进行分析,其次分析android内存管理机制的优缺点,最后提出内存管理优化的建议.     

数据库应用系统性能优化的几点策略

数据库应用系统．执行效率不高的主要由以下几个方面造成：数据库连接方式问题、系统应用架构问题、数据库设计问题、数据库管理与研究问题、网络通信因素的问题，基于以上的问题：可以采取如下几种方式加以解决：修改应用技术模式、建立历史数据库、利用数据库索引技术、利用数据库分区技术。     

基于QoS的卫星信息应用链服务调度方法

服务调度问题是卫星信息应用链功能结构设计完成之后必须解决的问题．在卫星信息应用链服务调度问题的相关概念进行描述之后,提出了卫星信息应用链的服务质量参数体系,为链的性能评价和服务选择提供了依据,并在此基础上建立了卫星信息应用链的服务调度问题的数学模型,提出了一种基于GA的服务调度算法．实验结果表明,本文所提出的服务质量参数体系能有效解决应用链性能评估问题,基于QoS的卫星信息应用链服务调度方法可行性较强．     

数据库应用系统性能优化的几点策略

数据库应用系统,执行效率不高的主要由以下几个方面造成:数据库连接方式问题、系统应用架构问题、数据库设计问题、数据库管理与研究问题、网络通信因素的问题,基于以上的问题,可以采取如下几种方式加以解决:修改应用技术模式、建立历史数据库、利用数据库索引技术、利用数据库分区技术.     

预测控制应用于工业过程的若干问题

本文论述了广义预测自校正控制器在工业过程应用中的一些问题：建模问题、辨识问题以及参数与目标函数的选取问题。并给出了三个具体应用的实例。     

高校现代教育技术应用中存在的问题及对策

现代化教育技术在高校教育中发挥着重要的作用.本文从现代教育技术的应用出发,围绕其在高等院校教学活动中的应用情况,阐述现代教育技术应用中存在的问题,并从问题着手,讨论解决当前存在的问题的方法与对策,为高校现代教育技术的应用提供可行性参考与建议.     

计算机局域网管理与安全问题研究

随着信息技术的不断进步以及计算机的普及应用,在计算机应用的过程中,出现了许多的问题,尤其是计算机局域网的安全问题。为了更好、更安全地应用计算机处理问题以及共享信息,就必须对计算机局域网的安全问题进行解决。该文主要分析计算机局域网的管理,并对计算机局域网的安全问题提出解决的对策。     

Simultaneously controllable fuzzy matrices

Let F be a set of n × n fuzzy matrices. F is called simultaneously controllable if there exists a permutation matrix P such that for each A ε F, C = [c_ij] = P A P^T satisfies c_ij ≥ c_ji for i > j, where is the max-min composition. In this paper, the necessary and sufficient conditions for a set of n × n fuzzy matrices to be simultaneously controllable will be established. A constructive algorithm which can determine a simultaneously controllable set of n × n fuzzy matrices is presented as well.     

Computation of functions of Hamiltonian and skew-symmetric matrices

In this paper we consider numerical methods for computing functions of matrices being Hamiltonian and skew-symmetric. Analytic functions of this kind of matrices (i.e., exponential and rational functions) appear in the numerical solutions of ortho-symplectic matrix differential systems when geometric integrators are involved. The main idea underlying the presented techniques is to exploit the special block structure of a Hamiltonian and skew-symmetric matrix to gain a cheaper computation of the functions. First, we will consider an approach based on the numerical solution of structured linear systems and then another one based on the Schur decomposition of the matrix. Splitting techniques are also considered in order to reduce the computational cost. Several numerical tests and comparison examples are shown.     

Eigen-solving via reduction to DPR1 matrices

Highly effective polynomial root-finders have been recently designed based on eigen-solving for DPR1 (that is diagonal + rank-one) matrices. We extend these algorithms to eigen-solving for the general matrix by reducing the problem to the case of the DPR1 input via intermediate transition to a TPR1 (that is triangular + rank-one) matrix. Our transforms use substantially fewer arithmetic operations than the QR classical algorithms but employ non-unitary similarity transforms of a TPR1 matrix, whose representation tends to be numerically unstable. We, however, operate with TPR1 matrices implicitly, as with the inverses of Hessenberg matrices. In this way our transform of an input matrix into a similar DPR1 matrix partly avoids numerical stability problems and still substantially decreases arithmetic cost versus the QR algorithm.     

Methods of computing weighted pseudoinverse matrices with singular weights

Three iterative processes are constructed and investigated for computing weighted pseudoinverse matrices with singular weights and ML-weighted pseudoinverse matrices. Two of them are based on the decompositions of the weighted pseudoinverse matrix with singular weights into matrix power series, and the third is a generalization of the Schulz method to nonsingular square matrices. Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 150–169, September–October, 1999.     

准Toeplitz测量矩阵的有限等距性质分析*

Toeplitz测量矩阵的卷积特性使压缩感知理论在线性时不变系统辨识问题中得到广泛应用。但在信号频率较高的场合往往需要对测量结果进行欠采样以利用压缩感知理论降低系统对采样频率的要求,这导致测量模型中的测量矩阵变为由Toeplitz矩阵中等间隔抽取若干行组成的子矩阵（准Toeplitz矩阵）。为此文章讨论了准Toeplitz矩阵作为测量矩阵的可行性。首先通过理论推导证明了准Toeplitz矩阵的有限等距性质,而后在仿真中比较了使用准Toeplitz矩阵与其他测量矩阵的重构效果。结果表明,准Toeplitz满足有限等距性质,使用准Toeplitz矩阵的重构效果与其他测量矩阵相近,可以作为压缩感知测量矩阵。     

A guided genetic algorithm for diagonalization of symmetric and Hermitian matrices

The eigenvalues and eigenvectors of a matrix have many applications in engineering and science, such us studying and solving structural problems in both the treatment of signal or image processing, and the study of quantum mechanics. One of the most important aspects of an algorithm is the speed of execution, especially when it is used in large arrays. For this reason, in this paper the authors propose a new methodology using a genetic algorithm to compute all the eigenvectors and eigenvalues in real symmetric and Hermitian matrices. The algorithm uses a general-purpose library developed by the authors for genetic algorithms (GALGA). The speed of execution and the influence of population size have been studied. Moreover, the algorithm has been tested in different matrices and population sizes by comparing the speed of execution to the number of the eigenvectors. This new methodology is faster than the previous algorithm developed by the authors and all eigenvectors can be obtained with it. In addition, the performance using the Coope matrix has been tested contrasting the results with another technique published in the scientific literature.     

Hankel/Toeplitz matrices and the static output feedback stabilization problem

The static output feedback (SOF) stabilization problem for general linear, continuous-time and discrete-time systems is discussed. A few novel necessary and sufficient conditions are proposed, and a modified SOF stabilization problem with performance is studied. For multiple-input single-output (or single-input multiple-output) systems the relation with a class of Hankel matrices, and their inverses, in the continuous-time case and with a class of Toeplitz matrices, in the discrete-time case, is established. These relationships are used to construct conceptual numerical algorithms. Finally, it is shown that, in the continuous-time case, the problem can be recast as a concave–convex programming problem. A few worked out examples illustrate the underlying theory.     

Solving certain queueing problems modelled by toeplitz matrices

By using the concept of generating function associated with a Toeplitz matrix, we analyze existence conditions for the probability invariant vector π of certain stochastic semi-infinite Toeplitz-like matrices. An application to the shortest queue problem is shown. By exploiting the functional formulation given in terms of generating functions, we devise a weakly numerically stable algorithm for computing the probability invariant vector π. The algorithm is divided into three stages. At the first stage the zeros of a complex function are numerically computed by means of an extension of the Aberth method. At the second stage the first k components of π are computed by solving an interpolation problem, where k is a suitable constant associated with the matrix. Finally, at the third stage a triangular Toeplitz system is solved and its solution is refined by applying the power method or any other refinement method based on regular splittings. In the solution of the triangular Toeplitz system and at each step of the refinement method, special FFT-based techniques are applied in order to keep the arithmetic cost within the O(n log n) bound, where n is an upper bound to the number of the computed components. Numerical comparisons with the available algorithms show the effectiveness of our algorithm in a wide set of cases.     

区间矩阵稳定的新充分必要条件

本文讨论了对称区间矩阵的稳定性并给出了一个简单的充分必要条件，同时还讨论了线性时变区间矩阵和非线性时变区间矩阵的稳定性。     

一种基于循环移位矩阵的LDPC码的研究

本文研究了一种基于循环移位矩阵结构的LDPC码,提出了一种高效的基于特征矩阵的LDPC码构造算法。研究结果表明,采用这种特定的结构和构造算法可以获得较短的构造时间,较低的编码复杂度和较少的记忆单元而且性能并未降低。