面向WS-BPEL的访问控制策略合成研究

在Web服务组合中,外部子服务通常会定义访问控制策略以保护资源被安全的使用,同时组合脚本中也存在着复杂的逻辑控制结构,这两点因素使安全管理员在描述组合服务的访问控制策略变得非常复杂。提出一种基于条件的访问控制策略模型以及基于该模型的策略合成代数,将WS-BPEL语言中常见控制结构映射成策略合成表达式,通过合成外部子服务的访问控制策略,生成组合服务的访问控制策略。最后,设计了原型系统描述策略合成的流程。     

t-Spanners for metric space searching

The problem of Proximity Searching in Metric Spaces consists in finding the elements of a set which are close to a given query under some similarity criterion. In this paper we present a new methodology to solve this problem, which uses a t-spanner G′(V, E) as the representation of the metric database. A t-spanner is a subgraph G′(V, E) of a graph G(V, A), such that E  A and G′ approximates the shortest path costs over G within a precision factor t.

Our key idea is to regard the t-spanner as an approximation to the complete graph of distances among the objects, and to use it as a compact device to simulate the large matrix of distances required by successful search algorithms such as AESA. The t-spanner properties imply that we can use shortest paths over G′ to estimate any distance with bounded-error factor t.

For this sake, several t-spanner construction, updating, and search algorithms are proposed and experimentally evaluated. We show that our technique is competitive against current approaches. For example, in a metric space of documents our search time is only 9% over AESA, yet we need just 4% of its space requirement. Similar results are obtained in other metric spaces.

Finally, we conjecture that the essential metric space property to obtain good t-spanner performance is the existence of clusters of elements, and enough empirical evidence is given to support this claim. This property holds in most real-world metric spaces, so we expect that t-spanners will display good behavior in most practical applications. Furthermore, we show that t-spanners have a great potential for improvements.     

基于业务规则的工作流管理系统模型

ECA规则通过条件与处理集中定义业务流程中活动与活动间的转换关系,并通过事件驱动机制驱动业务流程中相应业务逻辑实现,在一定程度上增加了系统代码的可维护性,但是并没有改变业务逻辑发生变化时需要修改系统代码以维护系统的现状.业务规则可准确描述业务流程中所有业务逻辑,建立与业务流程事件无关的运行机制,更加直接明确地反映业务需求,适应业务需求变化,而无需修改系统代码,基于此建立基于业务规则的工作流管理系统模型.     

地税税收业务管理信息系统设计

地税税收业务管理信息系统架构包含了业务架构、应用逻辑架构、应用技术架构3大架构。业务架构主要描述业务模块的分割;应用逻辑架构主要描述了各个子系统的功能和用户的界面;应用技术架构主要描述了一个平台／两个引擎／三层结构。E-BOS平台（一个平台）的引入使得用户能快速调整业务流程、快速改变业务规则、监控业务处理活动。两个引擎（业务过程引擎与业务规则引擎）为业务过程与业务规则的可配奠定了技术。三层结构则是常见的B／S／S结构。     

基于MVC模式的电子商务平台构造技术研究

网络设备的发展对电子商务平台系统结构设计及构造技术提出了新的要求，通过分析当前大型电子商务平台系统结构设计中的难点，基于J2EE平台MVC设计模式对电子商务系统结构进行层次化设计，阐述了MVC设计模式的原理及其优点。结合实例，提出系统架构设计方案并通过一个具体模块说明实现流程。     

面向电子商务的Web挖掘技术及其应用研究

电子商务过程中企业和组织面临一系列网络信息的获取问题,对解决这些问题的Web内容挖掘、Web结构挖掘、Web使用挖掘技术进行了综述,并介绍了Web挖掘技术在智能搜索引擎、企业危机管理、客户关系管理及个性化服务系统中的应用。     

高端J2EE Web应用的性能分析

介绍了互联网的发展对网络服务器性能的需求。分析了J2EE体系结构的分层和组件的特性。进行了J2EEWeb应用的分层软件架构风格的功能优化分配,以便使网络服务器在面对大规模并行访问时系统的响应速度和吞吐量能够满足高端应用的需求。借助于EJB独有的生命周期回调机制,论证了EJB承载企业逻辑的性能优势。分析了J2EE程序的编译特点对系统性能的影响。得出了用EJB组件基础设施可以构筑高效、健壮的高端J2EEWeb应用的结论。     

An Evolutionary Model of Endogenous Business Cycles

In this paper, we present an evolutionary model of industry dynamics yielding endogenous business cycles with ‘Keynesian’ features. The model describes an economy composed of firms and consumers/workers. Firms belong to two industries. The first one performs R&D and produces heterogeneous machine tools. Firms in the second industry invest in new machines and produce a homogenous consumption good. Consumers sell their labor and fully consume their income. In line with the empirical literature on investment patterns, we assume that the investment decisions by firms are lumpy and constrained by their financial structures. Moreover, drawing from behavioral theories of the firm, we assume boundedly rational expectation formation. Simulation results show that the model is able to deliver self-sustaining patterns of growth characterized by the presence of endogenous business cycles. The model can also replicate the most important stylized facts concerning micro- and macro-economic dynamics. Indeed, we find that investment is more volatile than GDP; consumption is less volatile than GDP; investment, consumption and change in stocks are procyclical and coincident variables; employment is procyclical; unemployment rate is anticyclical; firm size distributions are skewed but depart from log-normality; firm growth distributions are tent-shaped. JEL Classifications: C15, C22, C49, E17, E22, E32.     

Co-evolution of three mega-trends nurtures un-captured GDP – Uber’s ride-sharing revolution

Uber used a disruptive business model driven by digital technology to trigger a ride-sharing revolution. The institutional sources of the company’s platform ecosystem architecture were analyzed to explain this revolutionary change.Both an empirical analysis of a co-existing development trajectory with taxis and institutional enablers that helped to create Uber’s platform ecosystem were analyzed.The analysis identified a correspondence with the “two-faced” nature of ICT that nurtures un-captured GDP. This two-faced nature of ICT can be attributed to a virtuous cycle of decline in prices and an increase in the number of trips.We show that this cycle can be attributed to a self-propagating function that plays a vital role in the spinoff from traditional co-evolution to new co-evolution. Furthermore, we use the three mega-trends of ICT advancement, paradigm change and a shift in people’s preferences to explain the secret of Uber’s system success.All these noteworthy elements seem essential to a well-functioning platform ecosystem architecture, not only in transportation but also for other business institutions.     

西藏水资源业务数据的管理现状与建议

随着西藏自治区水资源管理信息化建设的发展,水资源业务数据从原来分散各处到初步实现统一管理,数据的获取方式日趋丰富,但管理和应用问题在实际工作中已凸现出来,亟待解决。针对当前水资源业务数据的管理现状及存在问题进行分析,并提出相应的建议,有助于提高水资源业务数据的时效性与质量,从而为落实最严格的水资源管理制度提供技术支撑,同时对今后其他业务数据的建设管理具有一定的参考价值。