基于MPLS与BGP的VPN构建与应用研究

针对GRE、IPSEC构建的虚拟私有网络存在数据隔离、互访控制难于实现等问题。文章分析了产生这些问题的根源,提出采用MPLS和BGP技术构建虚拟私有网络的设计思想,并通过仿真平台加以验证。实践证明,采用这种方法在解决路由冲突、数据隔离、站点间访问控制等方面要优于传统的VPN技术。     

产品协同设计的冲突消解方法研究

冲突在协同设计过程中是不可避免的，有效的冲突消解方法对协同设计的顺利进行是十分重要的。本文分析了协同设计过程中冲突产生的原因和特点，对协同设计过程中冲突消解的各种方法进行了研究。     

三峡-成都水调自动化系统数据库双向复制的应用实施

结合三峡-成都水调自动化系统数据业务特点和数据双向复制的应用实施方案,针对实施过程中的数据的冲突、数据区域权限管理等挑战以及运行效果进行了阐述和分析,具有重要实际意义和应用价值。     

一种基于OpenFlow的SDN访问控制策略实时冲突检测与解决方法

软件定义网络SDN(Software-Defined Networking)是由美国斯坦福大学Clean Slate研究组提出的一种新型网络创新架构,可通过软件编程的形式定义和控制网络,其控制平面和转发平面分离及开放性可编程的特点,为新型互联网体系结构研究提供了新的实验途径,也极大地推动了下一代互联网的发展.OpenFlow是SDN的主要协议,定义了SDN控制器与交换机之间的通信标准.目前,很多基于OpenFlow的SDN设备已经在实际中得到了部署.但是,基于OpenFlow的SDN却面临很多安全挑战.其中一个重要的挑战是如何建立一个安全可靠的SDN防火墙应用.由于OpenFlow协议的无状态性,现有的SDN防火墙可以被通过改写交换机中的流表项轻松绕过.针对这一安全威胁,作者提出了基于Flowpath的实时动态策略冲突检测与解决方法.通过获取实时的SDN网络状态,能够准确地检测防火墙策略的直接和间接违反,并且一旦发现冲突,可以基于Flowpath进行自动化和细粒度的冲突解决.最后,作者在开源控制器Floodlight上实现了一个安全增强的防火墙应用FlowVerifier,并基于Mininet对FlowVerifier的性能进行了评估.结果表明FlowVerifier能够检测和自动化地解决SDN网络中由于流表改写而引入的策略冲突及其带来的安全威胁.     

Variable precision intuitionistic fuzzy rough set model and applications based on conflict distance

Due to the complexity and uncertainty of the physical world, as well as the limitation of human ability to comprehend, it is very difficult for any single method of uncertainty to effectively deal with the decision‐making problem that exists in real life. So, it is natural for us to think about incorporating the advantages of various theories of uncertainty to develop a more powerful hybrid method of soft decision‐making. In view of this recognition, the thought and method of intuitionistic fuzzy sets and variable precision rough sets are used to construct a novel intuitionistic fuzzy rough set model. With respect to the fact that the information system is intuitionistic fuzzy, the idea of measuring intuitionistic fuzzy similarity is used to define conflict distance. After that, this concept is combined with the variable precision rough sets so that a variable precision intuitionistic fuzzy rough set model is established, and its properties are investigated. After proposing an attribute reduction algorithm based on variable precision intuitionistic fuzzy rough sets, a case study is used to verify the feasibility and effectiveness of our novel model. The results show that our model indeed improves the classification ability of earlier models and possesses some ability to tolerate faults through adjusting the parameter λ and the confidence threshold β; it realizes the correct classification and extracts the decision rules.     

Tourism as tragedy? Common problems with water in post-revolutionary Nicaragua

This paper examines the increased demand placed on limited water resources by a rapidly growing tourism sector in Playa Gigante, Nicaragua. Results from field campaigns suggest that recharge of the local aquifer may not meet burgeoning tourism demands for water. This paper also points to initial conflicts over water between locals and tourism operations, which are further complicated by ineffective implementation of national water policies and the common pool nature of groundwater. The conclusion discusses the need for more extensive research and better implementation of water policy through community governance and collaboration.     

Accelerating computation of Euclidean distance map using the GPU with efficient memory access

Recent graphics processing units (GPUs), which have many processing units, can be used for general purpose parallel computation. To utilise the powerful computing ability, GPUs are widely used for general purpose processing. Since GPUs have very high memory bandwidth, the performance of GPUs greatly depends on memory access. The main contribution of this paper is to present a GPU implementation of computing Euclidean distance map (EDM) with efficient memory access. Given a two-dimensional (2D) binary image, EDM is a 2D array of the same size such that each element stores the Euclidean distance to the nearest black pixel. In the proposed GPU implementation, we have considered many programming issues of the GPU system such as coalesced access of global memory and shared memory bank conflicts, and so on. To be concrete, by transposing 2D arrays, which are temporal data stored in the global memory, with the shared memory, the main access from/to the global memory enables to be performed by coalesced access. In practice, we have implemented our parallel algorithm in the following three modern GPU systems: Tesla C1060, GTX 480 and GTX 580. The experimental results have shown that, for an input binary image with size of 9216 × 9216, our implementation can achieve a speedup factor of 54 over the sequential algorithm implementation.     

Territorial targeting in EU private law

In a series of rulings given in the last few years, the Court of Justice of the European Union (EU) has made use of the concept of targeting by a trader of a particular territorial market as a device for determining the scope of European legislation on private law. The concept is of particular importance in the context of trading activities conducted by means of the Internet, though its significance is not confined to such activities. In particular, the European Court has used the concept of targeting for the purpose of restricting the substantive ambit of intellectual property rights created or harmonised by EU legislation. On the other hand, it has avoided use of the concept of targeting in the context of EU legislation allocating jurisdiction between the courts of the Member States, even in respect of disputes involving intellectual property, except where a legislative text specifically invokes such a concept. The instant paper endeavours to review the position as currently established by the European case-law, and to predict the likely further developments.     

一种改进的遗传算法在飞行冲突解脱

随着空中交通流量的增加,空中交通管理系统面临着越来越严重的航线拥挤问题.在自由飞行的环境下,发生冲突的可能性会大大增加,冲突解脱技术成为提高飞行安全与效益的一项关键技术.针对此问题,提出了一种改进的、能够快速准确进行航路规划的遗传算法,与标准遗传算法进行比较,取得了较好的优化效果.     

移动应用中基于物理隔离的数据同步方法

随着嵌入式技术、现代通讯技术的发展以及新一代通讯标准的出现,使得人们使用大规模智能移动设备进行移动计算成为可能。本文针对移动应用提出了一种在物理隔离网络环境下的数据同步方法,介绍了应用的背景,对同步系统进行总体设计,详细说明了数据同步操作的步骤及过程,然后详细论述了同步过程中冲突的检测、处理规则。采用增量式的同步方法,减少了数据交互量;同时,内外网物理隔离,保证了数据的安全性。