某电视台大楼ATM网络结构的分析与设计

仔细分析了某大型电视台ATM网络的具体和特殊的应用需求，在此基础上，系统地介绍了此网络的设计和实施，讨论了网络设计是如何充分利用现有的技术，有效地达到可扩展性、安全性和管理的灵活性的。     

Microprocessor architecture design with ATLAS

A concrete example of special purpose microprocessor development demonstrates how this simulation and analysis package facilitates the early stages of design. Simulation data enable the designer to improve performance quickly and easily with less probability of error     

A network pump

A designer of reliable multi level secure (MLS) networks must consider covert channels and denial of service attacks in addition to traditional network performance measures such as throughput, fairness, and reliability. We show how to extend the NRL data Pump to a certain MLS network architecture in order to balance the requirements of congestion control, fairness, good performance, and reliability against those of minimal threats from covert channels and denial of service attacks. We back up our claims with simulation results     

利用ACL在校园网内实现安全管理

阐述了ACL(Access Control List)基本原理、分类及简单配置方法,并结合实际案例进行了分析并配置,说明如何在校园网中使用ACL进行网络层访问权限控制,提高网络整体性能和安全.     

ACL构建企业网安全

访问控制列表ACL(Access Control List)通过对网络流量的控制,可过滤掉有害数据包,达到执行安全策略的目的。本文通过实例详细论述了如何利用访问控制列表来提高网络安全性能。     

基于数据的任务规划在复杂网络中的应用

复杂网络中目标任务的变化能够引起网络的自身演化,如何对任务负载进行平衡是提高网络自身性能的关键问题之一,以区域快递网络为研究对象,提出了基于动态数据和静态数据对对象进行配置、拆分、添加和抛弃的负载平衡规则,研究了其在任务规划中对网络负载平衡起到的作用,实验结果表明,提出的规则能够有效提高类似网络的稳定性和网络资源的合理配置。     

如何对校园网络的性能进行监视与维护

本文主要分析如何定期收集各种信息,分析网络中各种资源的使用率,及时发现影响网络性能的"瓶颈",并做出相应的优化或者增加网络设备从而提高网络性能.     

大量并发用户访问控制技术研究

为了应对网络用户规模的急剧增长,不断的改善网络硬件设备以及软件的性能。但是,仍然不能提供令用户满意的服务。主要研究了在大量并发用户存在的情况下如何应用通信代理技术、数据库连接池、集群技术改善数据库服务器的性能,为用户提供正常的网络服务。     

Tool Support for Refinement of Non-functional Specifications

Model driven architecture (MDA) views application development as a continuous transformation of models of the target system. We propose a methodology which extends this view to non-functional properties. In previous publications we have shown how we can use so-called context models to make the specification of non-functional measurements independent of their application in concrete system specifications. We have also shown how this allows us to distinguish two roles in the development process: the measurement designer and the application designer. In this paper we use the notion of context models to allow the measurement designer to provide measurement definitions at different levels of abstraction. A measurement in our terminology is a non-functional dimension that can be constrained to describe a non-functional property. Requiring the measurement designer to define transformations between context models, and applying them to measurement definitions, enables us to provide tool support for refinement of non-functional constraints to the application designer. The paper presents the concepts for such tool support as well as a prototype implementation.     

Cultural differences,experience with social networks and the nature of “true commitment” in Facebook

Formed on an analysis of design practices, the behaviour chain model stipulates that social network designer’s ultimate aim is to encourage users to adopt the social network site by entering a phase of true commitment. During this phase, social network users are driven to connect to known or unknown others by engaging in instrumental uses that create value and content and involve others, while staying active and loyal by investing time in the site. This paper investigates how designer’s intentions, as captured by the behaviour chain model, materialise through users’ reported practices in the social network site Facebook. A total of 423 Facebook users from 5 countries answered a questionnaire that allowed us to examine how 2 user characteristics, experience with the site, and culture, shape the nature of true commitment. Our findings show that experience with the site and even more so, culture, have an effect on users’ motivations for using Facebook, as well as their instrumental uses and the time they invest on the site. This analysis reifies the behaviour chain model by allowing designers to understand how the features they design are embodied in users’ practices.     

通用网络应用层信息流仿真

计算机的网络时代已经到来,它改变了每个人的观念和生活的方方面面,未来计算机的应用系统必然自主或不自主地向网络化的应用模式倾斜。对于实际运行中的网络应用系统,系统管理员需要对其运行效率进行监控和性能分析,以有效管理得到最佳服务;对于欲建的网络应用系统,网络设计者需要验证其设计方案的可行性,以有效投资建立最优网络环境;网络规模越大,网络性能的计算机仿真和性能分析工作越显重要。随着通信网络系统的日益复杂,对网络系统的性能分析和仿真都趋于使用专用的网络仿真分析软件。     

Toward an analytical solution to task allocation,processor assignment,and performance evaluation of network processors

Message-passing network-based multicomputer systems emerge as a potential economical candidate to replace supercomputers. Despite enormous effort to evaluate the performance of those systems and to determine an optimum scheduling algorithm (which is known as an NP-complete), we still lack a complete and a good performance model to analyze distributed computing systems. The model is complete if all system parameters, network parameters, communication overhead parameters, and application parameters are considered explicitly in the solution. A good performance model, like a good scientific theory, should be able to explain all normal behavior, predict any abnormality in the system, and allow the designer to adjust some of the parameters, while abstracting unimportant details.In this paper, we develop a good and complete performance model, which predicts a minimum finish time, equally the maximum speed up. In addition, we develop a closed form solution which forecasts the optimum share of the parallel job (task) that has to be assigned to each processor (node). Task assignment may then be undertaken in a distributed manner, which enhances the distributive nature of the system and, thus, improve system performance. Most importantly, our analytical solution presents a mechanism to select, based on system and application parameters, the optimum number of processors (nodes) that has to be assigned to a given parallel job.The model helps the designer to study the effect of each individual parameter on the overall system performance. This then becomes a tool for a designer of a multicomputer system to manage limited resources in an optimal manner paying attention only to those parameters that are most critical.     

模数混合采集系统设计中的噪声抑制

从影响典型模数混合采集系统噪声的各种因素入手,详细分析了引起模数混合采集系统噪声干扰的主要因素,针对每个环节提出了切实可行的抑制噪声的具体方法和措施,很大程度上提升了系统的性能,并给出了实例设计.     

机会网络节点协作缓存策略设计与实现

针对如何有效利用机会网络中节点间的协作关系以及节点有限的缓存资源,避免拥塞和提升数据传输性能的问题,提出一种机会网络协作缓存优化策略——HMP-Cache。该策略根据节点不同运动状态的特点,利用目标地址匹配标准选择协作缓存节点,采用同步Cache数据表达到局部域内缓存信息共享的目的。仿真实验结果表明,该策略能够有效控制数据访问的网络开销,降低网络热点数据访问延迟。     

基于排队论的嵌入式Web系统性能优化

以嵌入式Web技术的广泛应用为背景,探讨了一种在嵌入式Web系统中,利用单服务窗等待式M/M/1排队理论,建立嵌入式Web系统性能评估模型的方法。就如何利用该模型对ARM＋uCLinux实现的嵌入式Web系统进行网络性能评估,对嵌入式Web服务器的改进设计等问题进行了描述。     

并行差分进化算法

并行处理已经成为现代计算技术的一项关键技术。近几年软件的发展使得异构计算机集合可以作为并行计算资源使用,本文探讨如何在环形网络拓扑结构中将差分进化算法并行,以提高该方法的速度和性能。实验结果表明,子群中交流信息分配到不同节点的范围对该算法的性能有重大影响。此外,并不是差分进化中所有的突变策略都同样对此参数的值敏感。     

Modeling agent’s preferences by its designer’s social value orientation

Human social preferences have been shown to play an important role in many areas of decision-making. There is evidence from the social science literature that human preferences in interpersonal interactions depend partly on a measurable personality trait called, Social Value Orientation (SVO). Automated agents are often written by humans to serve as their delegates when interacting with other agents. Thus, one might expect an agent’s behaviour to be influenced by the SVO of its human designer. With that in mind, we present the following: first, we explore, discuss and provide a solution to the question of how SVO tests that were designed for humans can be used to evaluate agents’ social preferences. Second, we show that in our example domain there is a medium–high positive correlation between the social preferences of agents and their human designers. Third, we exemplify how the SVO information of the designer can be used to improve the performance of some other agents playing against those agents, and lastly, we develop and exemplify the behavioural signature SVO model which allows us to better predict performances when interactions are repeated and behaviour is adapted.     

宣告式网络程序设计语言比较研究

网络技术的发展和异构计算设备种类的增多给网络协议的设计开发带来诸多挑战。网络协议设计者面临的最基本问题是如何脱离繁琐的协议实现细节,而将主要精力放在协议的功能设计上。近年来,为了解决这个问题,宣告式网络程序设计语言,被提出。宣告式网络程序设计语言吸取数据库管理系统成功的经验,将网络划分为逻辑层和物理层。网络协议设计者只需利用其提供的高层编程抽象设计网络协议的功能,而不用关心繁杂的物理层实现。通过分析和比较不同宣告式网络程序设计语言,对其发展进行了总结,并指出了进行进一步的研究工作需要注意的问题。     

Multivariate evaluation of interactive robot systems

In designing robot systems for human interaction, designers draw on aspects of human behavior that help them achieve specific design goals. For instance, the designer of an educational robot system may use speech, gaze, and gesture cues in a way that enhances its student’s learning. But what set of behaviors improve such outcomes? How might designers of such a robot system determine this set of behaviors? Conventional approaches to answering such questions primarily involve designers carrying out a series of experiments in which they manipulate a small number of design variables and measure the effects of these manipulations on specific interaction outcomes. However, these methods become infeasible when the design space is large and when the designer needs to understand the extent to which each variable contributes to achieving the desired effects. In this paper, we present a novel multivariate method for evaluating what behaviors of interactive robot systems improve interaction outcomes. We illustrate the use of this method in a case study in which we explore how different types of narrative gestures of a storytelling robot improve its users’ recall of the robot’s story, their ability to retell the robot’s story, their perceptions of and rapport with the robot, and their overall engagement in the experiment.     

一种基于分区的移动P2P网络路由算法

校园内无线网络的普遍使用与移动设备性能的快速发展,使移动P2P技术得到了更多的关注。但当前对移动对等网络的研究还缺乏统一而明确的定义,还存在很多未能很好地解决的问题。文中的研究目的是如何有效组织移动节点,进行资源交换。针对校园无线网络环境,提出了一种基于分区模型的移动P2P网络结构。对节点历史行为统计,计算节点性能值。并利用分区网络模型和机会路由的思想提出了一种改进路由算法,实现区域内和区域间路由转发,降低了路由开销,提高了网络性能。