下一代网络管理业务提供模型的多视点分析

如何建立有效的管理业务提供模型来解决下一代网络NGN(Next Generation Network)中管理业务的开放问题是目前研究的难点。针对这个问题，提出了用多视点对管理业务提供模型进行分析的方法。首先对NGN管理业务的特点和特征进行了定义，基于此，从运营视点、网络视点和功能视点对管理业务模型进行了分析。运营视点定义了管理业务多使用者、提供者之间的关系；网络视点建立了包括用户平面在内的四层模型；功能视点描述了管理业务的执行、控制、存储、管理和对外接口功能。并对提出的多视点模型以实际的管理业务为例进行了验证。     

下一代互联网域间路由安全：威胁与对策

基于BGP的域间路由系统是下一代互联网的关键基础设施.本文系统地分析了下一代互联网域间路由系统的脆弱性,建立了下一代互联网域间路由的攻击模型对各种攻击目标和攻击方式进行描述,并从多个层次对BGP-4和BGP4＋的安全能力进行分析与比较.此外,我们给出了路由攻击检测系统方案,该方法可有效实现域间路由系统的安全控制     

SATCHMOREBID: SATCHMO(RE) with BIDirectional relevancy

SATCHMORE was introduced as a mechanism to integrate relevancy testing with the model-generation theorem prover SATCHMO. This made it possible to avoid invoking some clauses that appear in no refutation, which was a major drawback of the SATCHMO approach. SATCHMORE relevancy, however, is driven by the entire set of negative clauses and no distinction is accorded to the query negation. Under unfavorable circumstances, such as in the presence of large amounts of negative data, this can reduce the efficiency of SATCHMORE. In this paper we introduce a further refinement of SATCHMO called SATCHMOREBID: SATCHMORE with BIDirectional relevancy. SATCHMOREBID uses only the negation of the query for relevancy determination at the start. Other negative clauses are introduced on demand and only if a refutation is not possible using the current set of negative clauses. The search for the relevant negative clauses is performed in a forward chaining mode as opposed to relevancy propagation in SATCHMORE which is based on backward chaining. SATCHMOREBID is shown to be refutationally sound and complete. Experiments on a prototype SATCHMOREBID implementation point to its potential to enhance the efficiency of the query answering process in disjunctive databases. Donald Loveland, Ph.D.: He is Emeritus Professor of Computer Science at Duke University. He received his Ph.D. in mathematics from New York University and taught at NYU and CMU prior to joining Duke in 1973. His research in automated deduction includes defining the model elimination proof procedure and the notion of linear resolution. He is author of one book and editor/co-editor of two other books on automated theorem proving. He has done research in the areas of algorithms, complexity, expert systems and logic programming. He is an AAAI Fellow, ACM Fellow and winner of the Herbrand Award in Automated Reasoning. Adnan H. Yahya, Ph.D.: He is an associate professor at the Department of Electrical Engineering, Birzeit University, Palestine. He received his Diploma and PhD degrees from St. Petersburg Electrotechnical University and Nothwestern University in 1979 and 1984 respectively. His research interests are in Artificial Intelligence in general and in the areas of Deductive Databases, Logic Programming and Nonmonotonic Reasoning in particular. He had several visiting appointments at universities and research labs in the US, Germany, France and the UK. Adnan Yahya is a member of the ACM, IEEE and IEEE Computer Society.     

数据挖掘技术在入侵检测系统中的应用

入侵检测系统是近年来出现的网络安全技术。该文首先介绍了入侵检测系统的相关技术和评测指标,然后着重介绍了将数据挖掘技术应用于入侵检测系统,在此基础上设计了一个入侵检测系统结构框图,并提出了一种基于数据挖掘技术的入侵检测系统自适应产生模型,从而说明将数据挖掘技术应用于入侵检测是有效的。     

发电侧逐步市场化的竞价新模式

文中针对我国电力工业市场化改革的难点问题，提出了一种适合中国现阶段国情的发电侧逐步市场化的竞价新模式，其核心思想是：在电力市场化的时期，将发电机组划分为市场内，外两组。市场内机组实现竞价上网，市场外仍按核定成本发电，并可保留合同。市场内，外发电负荷的分配比例取决于各组的综合上网电价，该模式可较好地解决历史遗留问题，实现市场内机组竞价负荷的弹性化，平衡系统电价，避免在过短时间内全部市场化所产生的风险，用市场手段引导发电公司逐步走向市场，针对这一新的市场模式，该文建立了相应的模型，并提出了相应的计算方法，该模式和算法已经在实际系统中得到应用，为我国电力市场改革提供了新的思路。     

下一代网络的三种核心技术研究

NGN是未来网络的统一管理平台,提供包括音频、视频、数据在内的综合宽带业务,是各种技术融合与网络融合的产物。文章介绍了NGN的三大核心技术,即软交换技术、智能光网络、IPv6协议。重点探讨了软交换的定义、特点、及功能,智能光网络概念、体系结构、控制平面功能,IPv6协议特点及其对IPv4的发展。通过上述内容的阐述,旨在增进对NGN的全面了解。     

PDE blending surfaces with C continuity

In this paper, we propose to use a general sixth-order partial differential equation (PDE) to solve the problem of C² continuous surface blending. Good accuracy and high efficiency are obtained by constructing a compound solution function, which is able to both satisfy the boundary conditions exactly and minimise the error of the PDE. This method can cope with much more complex surface-blending problems than other published analytical PDE methods. Comparison with the existing methods indicates that our method is capable of generating blending surfaces almost as fast and accurately as the closed-form method and it is more efficient and accurate than other extant PDE-based methods.     

国内外太阳能光伏发电发展综述

文章描述了国外光伏发电状况，介绍了国内尤其是青海省光伏发电的发展现状，随着我国太阳能光伏发电技术的不断提高，为产业发展开拓了新思路，市场前景日趋广阔。     

A CNC interpolation algorithm for boundary machining

This paper presents an efficient and accurate algorithm for machining boundaries formed at the intersection of two surfaces, an important manufacturing problem in CNC machining. The algorithm is developed using a locus tracing technique implemented on the basis of Danielson's step selection rules. A vertical ball-end milling cutter moves along the considered boundary, in contact with the two surfaces. The algorithm guides the center of the spherical end of the cutter, to maintain exact contact (within 1 step) along the entire path. A seamless formulation is used, allowing the contact points to move freely from the ball-end to the cutter periphery and vice-versa. The surfaces forming the boundary may be implicitly or parametrically defined. The reliability of the algorithm is demonstrated for both cases, by treating a complex boundary machining example. The boundary considered is formed by the intersecting quadratic surfaces of a sphere and an elliptic hyperboloid.     

一种随机化的软件模型生成方法

模型转换是模型驱动开发的核心技术. 当要把模型转换用于工业生产时, 其性能成为影响这一技术成败的关键因素之一. 为了测试模型转换程序的性能, 需要能够快速地生成一组具有较大规模的模型数据用于作为测试的输入数据. 本文提出一种随机化的模型生成方法. 该方法能够根据元模型的定义以及用户输入的约束条件随机、正确地生成模型文件. 实验结果也表明, 本方法和其它方法相比具有更好的生成效率, 从而更加适合支持模型转换的性能测试.