Using minimal cuts to optimize network reliability for a stochastic computer network subject to assignment budget

In our modern society, information and data are usually transmitted through a computer network. Since the computer network's reliability has a great impact on the quality of data transmission, many organizations devote to evaluating or improving network reliability, especially for network reliability optimization. This study focuses on such a confronted problem that is to find the optimal transmission line assignment to the computer network such that network reliability is maximized subject to the budget constraint. Each transmission line owns several states due to failure, maintenance, etc., and thus the computer network associated with any transmission line assignment is called a stochastic computer network. Network reliability is the probability that the computer network can transmit the specified units of data successfully. Because the discussed problem is NP-hard, an optimization algorithm that integrates the genetic algorithm, minimal cuts and Recursive Sum of Disjoint Products is proposed. Experimental results illustrate the solution procedure and show that the proposed algorithm can be executed in a reasonable time.     

Two-commodity reliability evaluation of a stochastic-flow network with varying capacity weight in terms of minimal paths

A real-life manufacturing system can be modeled as a stochastic-flow network in which nodes stand for the machine stations, and arcs stand for the shipping media. In terms of minimal paths (MPs), this paper presents a stochastic-flow network model with four characteristics: (1) both nodes and arcs have multiple possible capacities, and may fail; (2) each component (arc/node) has both capacity and cost attributes; (3) two-commodity are proceeded; and (4) the capacity weight varies with arcs, nodes, and types of commodity. We study the possibility of two-commodity to be transmitted through this network simultaneously under the budget constraint. Such a possibility is named as the system reliability. The MPs play the role of media to describe the relationship among flow assignments and capacity vectors. Subsequently, a simple algorithm, in terms of MPs, is proposed to evaluate the system reliability. From the capacity management and decision making viewpoints, managers may adopt the system reliability as a performance index to measure the system capacity and finally to determine if it meets the customers’ orders or not.     

提高计算机网络可靠性的方法分析

在信息化时代,随着科技的不断发展,网络更以惊人的速度向前发展,不断更新技术,便捷的网络工具在通讯上逐渐主流化,方便快捷的优势使人们逐渐接受了快速化的网络信息生活.网络通讯的确给我们带来了太多的便捷,但是也存在大量的问题,网络也存在大量的问题,网络安全得不到保障的话,会给我们的生活带来很多麻烦,网络黑客往往会攻击我们的程序,会使我们造成很大的损失,甚至损失无法估量.随着信息的不断发展,我们在利用网络的同时,也应该加强网络的防范,在自己充分利用网络的同时,也要防止网络的侵害,让网络更好的为其服务.因此,提高计算机网络可靠性就显得尤为必要.笔者从计算机网络可靠性的概念和设计原则出发就如何提高计算机网络可靠性提出了自己的见解.     

基于云计算下的计算机网络安全问题研究

云计算作为计算机技术与互联网有效结合的里程碑,其引领IT界和信息领域的进一步技术变革。在云计算快速发展形势下,其中云计算的网络安全问题变得十分重要。本文通过对云计算的理念与存在的问题分析基础上,结合实际状况总结出相应的网络安全保护对策。     

A hybrid ant-tabu algorithm for solving a multistate flow network reliability maximization problem

Network reliability optimization for multistate flow networks (MFN) is an important issue for many system supervisors. Network reliability maximization for an MFN by determining the optimal component assignment, where a set of multistate components are ready to be assigned to the network, is a common problem. Previous research solved this problem by developing and applying genetic algorithm. Ant colony optimization (ACO) finds a good solution quickly by utilizing the experience of the proceeding ant but sometimes falls into local optimum. Tabu search (TS) adopts a tabu list to avoid searching in the same direction, and thus it explores other possible solutions. This strategy enlarges the search space. Therefore, we propose a hybrid ant-tabu (HAT) algorithm integrating the advantages of ACO and TS to solve this problem, where network reliability is evaluated in terms of minimal paths (MPs) and Recursive Sum of Disjoint Products. Experimental (RSDP) results show that the proposed HAT has better computational efficiency than several soft computing algorithms for networks with more than six MPs or 10 arcs.     

网格计算经济中资源的可靠性控制

针对网格资源的可靠性问题,提出了一个包括注册真实性,信任评价和调度契约构成的分层控制模型.针对该模型,提出了资源注册信息的验证方法和契约的模式.仿真实验表明,该模型在资源注册信息验证的基础上,优先调度了信息真实、运行可靠的资源,通过可靠性资源的选择和控制促进了计算经济的可靠性.     

Stochastic computer network with multiple terminals under total accuracy rate

From the viewpoint of service level agreements,data transmission accuracy is one of the critical performances for assessing Internet by service providers and enterprise customers.The stochastic computer network(SCN),in which each edge has several capacities and the accuracy rate,has multiple terminals.This paper is aimed mainly to evaluate the system reliability for an SCN,where system reliability is the probability that the demand can be fulfilled under the total accuracy rate.A minimal capacity vector allows the system to transmit demand to each terminal under the total accuracy rate.This study proposes an efficient algorithm to find all minimal capacity vectors by minimal paths.The system reliability can then be computed in terms of all minimal capacity vectors by the recursive sum of disjoint products(RSDP) algorithm.     

A genetic algorithm for optimal flow assignment in computer network

In this paper, we consider the optimal flow assignment problem of finding a set of link flows that satisfy the requirements and minimize the average end-to-end network delay for a given topology characterized by the capacities and costs of links. This problem can be formulated as a nonlinear programming problem.

In recent years, a growing body of literature suggests the use of genetic algorithm as one of powerful heuristic search methods to deal with many hard-solving problems. For highly constrained problems, conventional genetic operators often yield illegal solutions in the sense of violation of system constraints.

In this study, we present an implementation of genetic algorithms to the optimal flow assignment problem. Non-uniform mutation and arithmetical crossover are adopted to guarantee the legitimation of offspring. Simulation results show that the proposed approach performs well for this problem.     

计算机网络安全分析研究简

计算机网络安全是促进网络事业健康发展的前提,在分析网络安全产生的原因及目前网络所面临威胁的基础上,以安全防御作为出发点,从技术及管理两大方面,提出了防护计算机网络安全的具体措施与有效方案。如何保护计算机信息的问题显的越来越重要。该文旨在分析计算机网络面临的威胁和存在的安全隐患,并提出防范技术,提高计算机网络安全。     

医院计算机网络安全与维护经验技巧

结合医院的实际情况,从三个方面讨论计算机网络在医院管理中的安全维护问题与经验技巧.     

Computer network reliability optimization under double-resource assignments subject to a transmission budget

This paper discusses a double-resource assignment problem to maximize network reliability for a computer network. The resources are separated into two types: one is transmission line and another is transmission facility. In particular, each resource is multistate due to full failure, partial failure, or maintenance. Such a network assigned with multistate resources is usually modeled as a stochastic-flow network. Furthermore, each resource should have a transmission cost in reality. Hence, the network reliability is the probability that a specified demand is transmitted through the network successfully subject to a transmission budget. This paper devotes to find out the optimal double-resource assignment with maximal network reliability. An optimization algorithm combining the genetic algorithm, the minimal paths, and the Recursive Sum of Disjoint Products is developed to solve the proposed problem. The experimental results show that the proposed algorithm can be executed in a reasonable time.     

The system reliability analyser tool

This paper describes the design and evaluation of a socio-technical design support system, the system reliability analyser (SRA). The tool is used to validate non-functional system requirements, such as system reliability. It employs a Bayesian belief network (BBN) model to assess system reliability (Pearl in Probabilistic reasoning in intelligent systems: networks of plausible information, 1988) based on a variety of high-level operational scenarios. The tool diagnoses problematic areas in future system models and assists in the identification of their causes. The evaluation of the tool demonstrated that it supported the task it was intended to do. The evaluation also identified usability problems in the current visualisations and illustrated their resolution.     

子网络的连接模式对关联网络可靠性影响研究

为了分析关联网络中子网络之间连接方式对网络可靠性的影响,根据不同子网络之间连接的度相关性,建立关联网络中子网络之间的连接模型,以节点之间非交叉路径的最大条数为可靠性测度,对由4个子网络组成的网络系统进行了分析。结果表明,当子网络之间的连接具有异配性时,网络具有较高的可靠性,但过大的异配性反而会降低网络的可靠性。     

针对安全问题的可信计算研究

本文采用安全状态转移模型化的方法对现有计算机安全体系结构进行分析。在体系结构中引入引用监控器来判断主体请求是否合理。之后通过比较传统计算机体系结构与可信计算平台的相似点,阐述可信计算的原理和应用。最后对可信计算在未来发展过程中可能遇到的难点进行深入探讨。     

不交和公式及其在网络可靠度计算中的应用

提出了不交和公式及其在网络可靠度计算中的应用,和传统的算法相比,该算法操作简便,易于实现,计算复杂度小的点,从而适合于大型网络可靠度的计算。     

Optimal resource assignment to maximize multistate network reliability for a computer network

Computer network is a major tool to transmit data in our modern society. How to evaluate and enhance network reliability is thus an important issue for organizations, especially to maximize network reliability. A computer network is a multistate network in which each edge has several possible capacities with a probability distribution and may fail. The multistate network reliability is the probability that the maximal flow is no less than a given demand. From the standpoint of quality management, a further problem is to reassign the existing resources for maximizing multistate network reliability without changing the network topology. Hence, this paper focuses on the resource assignment problem to propose an efficient approach based on the simple genetic algorithm. In which, a resource assignment is represented as a chromosome and the corresponding multistate network reliability is the fitness value of the chromosome. The experimental results show that the proposed algorithm can derive the optimal resource assignment in a reasonable time.     

高校机房网络安全管理探讨

高校机房网络的信息安全是高校信息管理中一个非常重要的方面,本文主要对学校机房网络的信息的安全的重要性进行阐述,并且提出了一些切实可行的计算机机房信息管理技术和措施,这样就有利于学校计算机机房网络安全的管理,进而得到结论,高校的各级领导、组织和部门的工作人员要对机房信息系统网络安全要高度的重视,并且要对其进行有效的维护和管理.     

Maintenance reliability estimation for a cloud computing network with nodes failure

The cloud computing network (CCN) has become a new paradigm for the business and clients as the development of information technology. To guarantee the CCN keep a good quality of service (QoS), the maintenance action is necessary when the CCN falls to a specific state such that it cannot afford enough capacity to meet demand d. In the CCN, edges and nodes have various capacities due to failure, partial failure, or maintenance; thus, the CCN has several possible states. This paper proposes an algorithm to estimate the performance of a CCN under maintenance budget with nodes failure. Hence, the maintenance reliability is developed to measure the capability that the CCN can send d units of data from the cloud to the client through multiple paths under the maintenance budget and time constraints. Furthermore, the system supervisor can conduct the sensitive analysis to improve/investigate the most important part in a large CCN afterwards.     

Software reliability prediction by soft computing techniques

In this paper, ensemble models are developed to accurately forecast software reliability. Various statistical (multiple linear regression and multivariate adaptive regression splines) and intelligent techniques (backpropagation trained neural network, dynamic evolving neuro-fuzzy inference system and TreeNet) constitute the ensembles presented. Three linear ensembles and one non-linear ensemble are designed and tested. Based on the experiments performed on the software reliability data obtained from literature, it is observed that the non-linear ensemble outperformed all the other ensembles and also the constituent statistical and intelligent techniques.