智能计算几种经典算法解析

随着计算机技术的飞速发展,智能计算方法的应用领域也越来越广泛。本文介绍了当前存在的一些智能计算方法,阐述了其工作原理和特点,同时对智能计算方法的发展进行了展望。     

智能计算几种经典算法解析

随着计算机技术的飞速发展,智能计算方法的应用领域也越来越广泛。本文介绍了当前存在的一些智能计算方法,阐述了其工作原理和特点,同时对智能计算方法的发展进行了展望。     

无自衡对象闭环测试的计算方法

本文提出一种闭环测试无自衡对象闭环测试的计算方法，是文献〔１〕和〔３〕所做工作的深化，所得结果可用于离线参数测试和调节器参数自整定。     

需求工程的质量评价准则

需求工程是软件系统开发生命周期的初始阶段,其最终结果是得到关于用户需求的准确,全面,形式化的需求描述。虽然人们已经认识到需求工程的质量是整个系统开发的关键,但是目前尚没有确定统一的质量评价体系。从需求工程的基本活动内容出发,结合案例研究和软件开发经验,定义了需求工程质量评价的七项准则,并给出了质量因素的评价方法。     

相似理论在仿真可信性分析中的应用

相似理论是计算机仿真的基础,它在建立仿真模型、仿真可信性评估等方面都有很好的指导作用。基于相似理论的基本原理,讨论系统仿真的可信性问题,提出了基于相似理论的系统仿真可信性分析的基本思想和方法,并对如何评估仿真系统的相似度问题在理论上做了一定的研究和探讨。     

一种改进的矩阵幂运算及其性能分析

基于流水光总线的可重构线性阵列系统是一种建立在光总线上的并行高效计算模型。该文给出了一种LARPBS模型上改进的矩阵幂运算并行算法,并对其可扩展性和复杂性进行分析,通过分析可以看出,该算法是目前速度最快、成本最优的并行矩阵幂运算算法。     

非计算机专业《计算机应用基础》课程改革探索

高校的《计算机应用基础》课程是为非计算机专业学生开设的学习计算机知识和应用的课程.针对《计算机应用基础》教程的教学现状和存在问题,结合一些教学实践和经验,对《计算机应该基础》课程提出几点建议.     

浅析高校数字校园建设方案及实施模式

介绍数字校园的概念及国内高校数字校园建设概况,给出高校数字校园建设方案,并对高校数字校园的实施模式进行分析探讨。     

An Introduction to Simulated Annealing Algorithms for the Computation of Economic Equilibrium

Economic equilibrium computation has raised the issue of global optimization algorithms since economic equilibrium problems can be cast as a global optimization problem. However, nearly all conventional algorithms stop when they find a local optimum. Over the last decade a number of new optimization algorithms have appeared, simulated annealing is one of them. It is a powerful stochastic search algorithm applicable to a wide range of problems for which little prior knowledge is available, and it asymptotically probabilistically converges to a global optimum. In this paper, we will give a brief introduction to simulated annealing and apply it to the computation of economic equilibrium. We also reported our computational experience in the paper. This early result shows that the application of simulated annealing to computation of economic equilibrium is encouraging and it deserves further research.     

An Iterative Substructuring Method for div-stable Finite Element Approximations of the Oseen Problem

We apply an iterative substructuring algorithm with transmission conditions of Robin–Robin type to the discretized Oseen problem appearing as a linearized variant of the incompressible Navier–Stokes equations. Here we consider finite element approximations using velocity/pressure pairs which satisfy the Babuška–Brezzi stability condition. After proving well-posedness and strong convergence of the method, we derive an a-posteriori error estimate which controls convergence of the discrete subdomain solutions to the global discrete solution by measuring the jumps of the velocities at the interface. Additionally we obtain information how to design a parameter of the Robin interface condition which essentially influences the convergence speed. Numerical experiments confirm the theoretical results and the applicability of the method. Received February 18, 2000; revised February 21, 2001     

一种对混合系统进行高层系统需求分析并建立计算模型的方法

本文提出了一种对混合系统进行高层系统需求分析并建立计算模型的方法。文中不仅使用了场景和顺序图来提炼和描述混合系统中的离散事件通信,还为系统中的每个过程或构件提供了自动构建高层计算模型的方法。     

Evaluating the Impact of User Characteristics and Different Layouts on an Interactive Visualization for Decision Making

There is increasing evidence that user characteristics can have a significant impact on visualization effectiveness, suggesting that visualizations could be designed to better fit each user's specific needs. Most studies to date, however, have looked at static visualizations. Studies considering interactive visualizations have only looked at a limited number of user characteristics, and consider either low‐level tasks (e.g., value retrieval), or high‐level tasks (in particular: discovery), but not both. This paper contributes to this line of work by looking at the impact of a large set of user characteristics on user performance with interactive visualizations, for both low and high‐level tasks. We focus on interactive visualizations that support decision making, exemplified by a visualization known as Value Charts. We include in the study two versions of ValueCharts that differ in terms of layout, to ascertain whether layout mediates the impact of individual differences and could be considered as a form of personalization. Our key findings are that (i) performance with low and high‐level tasks is affected by different user characteristics, and (ii) users with low visual working memory perform better with a horizontal layout. We discuss how these findings can inform the provision of personalized support to visualization processing.     

An Efficient Modular Method for the Control of Concurrent Discrete Event Systems: A Language-based Approach

In this paper, we are interested in the control of a particular class of Concurrent Discrete Event Systems defined by a collection of components that interact with each other. We investigate the computation of the supremal controllable language contained in the language of the specification. We do not adopt the decentralized approach. Instead, we have chosen to use a modular centralized approach and to perform the control on some approximations of the plant derived from the behavior of each component. The behavior of these approximations is restricted so that they respect a new language property for discrete event systems called partial controllability condition that depends on the specification. It is shown that, under some assumptions, the intersection of these “controlled approximations” corresponds to the supremal controllable language contained in the specification with respect to the plant. This computation is performed without having to build the whole plant, hence avoiding the state space explosion induced by the concurrent nature of the plant. It is finally shown that the class of specifications on which our method can be applied strictly subsumes the class of separable specifications.

Computational Tools for the Analysis of Market Risk

The estimation and management of risk is an important and complex task faced by market regulators and financial institutions. Accurate and reliable quantitative measures of risk are needed to minimize undesirable effects on a given portfolio fromlarge fluctuations in market conditions. To accomplish this, a series of computational tools has beendesigned, implemented, and incorporated into MatRisk, an integratedenvironment for risk assessment developed in MATLAB. Besides standard measures, such as Value at Risk(VaR), the application includes other more sophisticated risk measures that address the inability of VaRproperly to characterize the structure of risk. Conditionalrisk measures can also be estimated for autoregressive models with heteroskedasticity, including some novel mixture models. These tools are illustrated with a comprehensive risk analysis of the Spanish IBEX35 stock index.     

Evaluating image quality measures to assess the impact of lossy data compression applied to climate simulation data

Applying lossy data compression to climate model output is an attractive means of reducing the enormous volumes of data generated by climate models. However, because lossy data compression does not exactly preserve the original data, its application to scientific data must be done judiciously. To this end, a collection of measures is being developed to evaluate various aspects of lossy compression quality on climate model output. Given the importance of data visualization to climate scientists interacting with model output, any suite of measures must include a means of assessing whether images generated from the compressed model data are noticeably different from images based on the original model data. Therefore, in this work we conduct a forced‐choice visual evaluation study with climate model data that surveyed more than one hundred participants with domain relevant expertise. In addition to the images created from unaltered climate model data, study images are generated from model data that is subjected to two different types of lossy compression approaches and multiple levels (amounts) of compression. Study participants indicate whether a visual difference can be seen, with respect to the reference image, due to lossy compression effects. We assess the relationship between the perceptual scores from the user study to a number of common (full reference) image quality assessment (IQA) measures, and use statistical models to suggest appropriate measures and thresholds for evaluating lossily compressed climate data. We find the structural similarity index (SSIM) to perform the best, and our findings indicate that the threshold required for climate model data is much higher than previous findings in the literature.     

能耗并行加速比:高性能计算系统综合性能的有效度量

随着并行系统规模的扩大,高性能计算系统运行时消耗的能耗也在急剧增长,过高的能耗也给系统的可靠性、稳定性等方面带来严峻挑战。在这种情形下,能耗问题受到了前所未有的关注。因此,设计和研究高性能计算系统,需要在考虑高计算性能的同时兼顾系统低能耗的要求,这为高性能计算系统的度量模型提出了新的挑战。于是,大规模并行系统逐渐从高性能走向高效能的衡量标准。基于此,本文采用加速比度量指标,从系统可扩展角度将计算性能和能量消耗要素进行综合,提出了一种度量高性能计算系统综合性能的能耗并行加速比模型。该模型能够直观地反映并行计算系统的效能,旨在指导系统设计和应用研究。最后,通过对该模型的分析和模拟,验证了模型的有效性。     

An Externally Replicated Experiment for Evaluating the Learning Effectiveness of Using Simulations in Software Project Management Education

The increasing demand for software project managers in industry requires strategies for the development of the management-related knowledge and skills of the current and future software workforce. Although several approaches help teach the required skills in a university setting, few empirical studies are currently available to characterize and compare their effects. This paper presents results of an externally replicated controlled experiment that evaluates the learning effectiveness of using a process simulation model for educating computer science students in software project management. While the experimental group applies a system dynamics (SD) simulation model, the control group uses the well-known COCOMO model as a predictive tool for project planning. The results of the empirical study indicate that students using the simulation model gain a better understanding about typical behavior patterns of software development projects. The combination of the results from the initial experiment and the replication corroborates this finding. Additional analysis shows that the observed effect can mainly be attributed to the use of the simulation model in combination with a web-based role-play scenario. This finding is strongly supported by information gathered from the debriefing questionnaires of subjects in the experimental group. They consistently rated the simulation-based role-play scenario as a very useful approach for learning about issues in software project management.     

An Information Theory Framework for the Analysis of Scene Complexity

In this paper we present a new framework for the analysis of scene visibility and radiosity complexity. We introduce a number of complexity measures from information theory quantifying how difficult it is to compute with accuracy the visibility and radiosity in a scene. We define the continuous mutual information as a complexity measure of a scene, independent of whatever discretisation, and discrete mutual information as the complexity of a discretised scene. Mutual information can be understood as the degree of correlation or dependence between all the points or patches of a scene. Thus, low complexity corresponds to low correlation and vice versa. Experiments illustrating that the best mesh of a given scene among a number of alternatives corresponds to the one with the highest discrete mutual information, indicate the feasibility of the approach. Unlike continuous mutual information, which is very cheap to compute, the computation of discrete mutual information can however be quite demanding. We will develop cheap complexity measure estimates and derive practical algorithms from this framework in future work.     

信息系统项目的风险管理探讨

项目风险管理是项目管理的重要组成部分,信息系统项目的风险管理在信息系统项目的管理中起着至关重要的作用。信息系统项目的风险管理能为企业领导提供更好的决策支持,为企业运营提供更有效的管控手段。通过对信息系统项目的风险进行定性分析和定量分析,对风险进行排序和量化,然后对风险进行实时的动态监测,制定风险应对措施。风险具有多样性、复杂性、隐蔽性等特征,要对关涉信息系统项目安全的风险因素进行识别与分析,然后通过对风险进行监控和跟踪,实现信息系统项目管理的良性循环。