Declarative planning in procedural agent architectures

Practical agent languages and their corresponding architectures have often relied on a static plan library with more or less direct trigger-response activation mechanisms as a source for agent behaviours for the sake of runtime efficiency. Although efficient, such a language design choice severely limits an agent’s ability to reason about its goals and adapt to unforeseen circumstances after being deployed. This effectively delegates the task of planning to the designers themselves, who must design plan libraries able to cope with every foreseeable situation an agent might find itself in by designing plans to deal with any contingency. In this paper we develop a formal conversion process from traditional BDI agent languages into declarative planning. Using this conversion process, we show how to integrate domain independent planning algorithms into the BDI interpreter, allowing a designer to program an agent not only through the trigger-response mechanism used in traditional languages, but also in terms of declarative goals. Our contribution here is twofold: firstly we increase an agent’s ability to cope with unforeseen situations and secondly we unburden an agent designer from having to define multiple plan combinations that could be easily generated by a planner.     

描述性语言与知识库系统

1．引言 在数据库领域,由于描述性语言SQL的成功使用,描述性更加受到重视[1,2,3,4]。描述性语言Data-log的提出,使得一些学者认为知识库语言应该是描述性的程序设计语言[4]。然而多年来的研究,不但没有开发出一个描述性的知识库程序设计语言,而且还阻碍了知识库的实用化[5]。本文研究了描述性与逻辑语言、知识库语言之间的关系,提出了三个观点：1)描述性语言是计算不完备的,因此不能作为独立的程序设计语言；2)逻辑语言是描述性语言的合适形式；3)追求语言的描述性是知识库系统实用化的障碍之一。     

Cost-Sensitive Diagnosis of Declarative Programs

Diagnosis methods in debugging aim at detecting bugs of a program, either by comparing it with a correct specification or by the help of an oracle (typically, the user herself). Debugging techniques for declarative programs usually exploit the semantical properties of programs (and specifications) and generally try to detect one or more “buggy” rules. In this way, rules are split apart in an absolute way: either they are correct or not. However, in many situations, not every error has the same consequences, an issue that is ignored by classical debugging frameworks. In this paper, we generalise debugging by considering a cost function, i.e. a function that assigns different cost values to each kind of error and different benefit values to each kind of correct response. The problem is now redefined as assigning a real-valued probability and cost to each rule, by considering each rule more or less “guilty” of the overall error and cost of the program. This makes possible to rank rules rather than only separate them between right and wrong. Our debugging method is also different from classical approaches in that it is probabilistic, i.e. we use a set of ground examples to approximate these rankings.     

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。     

SelfMotion: A declarative approach for adaptive service-oriented mobile applications

Modern society increasingly relies on mobile devices. This explains the growing demand for high quality software for such devices. To improve the efficiency of the development life-cycle, shortening time-to-market while keeping quality under control, mobile applications are typically developed by composing together ad-hoc developed components, services available on-line, and other third-party mobile applications. Applications are thus built as heterogeneous compositions, whose characteristics strongly depend on the components and services they integrate. To cope with unpredictable changes and failures, but also with the various settings offered by the plethora of available devices, mobile applications need to be as adaptive as possible. However, mainstream adaptation strategies are usually defined imperatively and require complex control strategies strongly intertwined with the application logic, yielding to applications that are difficult to build, maintain, and evolve. We address this issue by proposing a declarative approach to compose adaptive heterogeneous mobile applications. The advantages of this approach are demonstrated through an example inspired by an existing worldwide distributed mobile application, while the implementation of the proposed solution has been validated through a set of simulations and experiments aimed at illustrating its performance.     

基于变更事件驱动的微服务组合平台设计与实现

微服务组合领域尚处于未成熟阶段,需要更完善的解决方案,因此设计了一个基于变更事件驱动的微服务组合平台。该平台相比现有的解决方案,在领域特定语言层面上支持细粒度数据访问控制,并进一步丰富了语言表现力。引入Spring Cloud Netflix生态系统,解决平台中微服务不能动态部署的问题,提高了健壮性。对于触发微服务组合的事件,增加了对Web资源的变更检测,即对XML文档的内容和结构2个层面的比较,并对现有的XML文档内容层面的比较方法进行优化,综合考虑了内容和结构的相似度度量。实验结果表明,该微服务组合平台更加完善、丰富,注重私隐保护,容错性更强,在算法时间效率上亦有提升。     

comFlow:一个支持Web服务动态组合的原型系统

随着电子商务的迅速发展及用户对企业服务质量和及时信息反馈的要求越来越高,企业内及企业间各个系统之间的交互对企业的发展越来越重要.结合Web服务技术和流程建模技术,设计并初步实现了支持Web服务动态组合和执行的原型系统,给出了comFlow的系统架构,并描述它的组成部分.     

基于宣告式网络的网络溯源系统的设计与实现

网络的举证分析、错误诊断在网络管理和安全方面正发挥着越来越重要的作用。这就要求网络管理系统具有网络溯源的功能。网络溯源可以用于跟踪信息在网络上流传的轨迹,确定信息数据来源。提出了一个网络溯源系统(NPS)框架的设计与实现,该框架可以支持在大规模的分布式环境中获得网络溯源,采用了新近提出的宣告式网络技术来有效地维护和查询分布式网络溯源。该框架采用基于引用的方式来传递溯源信息,采用有向无环图来表示溯源信息,在分布式网络中实现了高效的网络溯源。在ns-3构建的模拟网络中进行了仿真实验,实验结果表明该网络溯源系统框架可以有效地支持一个大规模分布式网络的溯源计算,与传统方法相比显著地减少了带宽的开销。     

Declarative RDF graph generation from heterogeneous (semi-)structured data: A systematic literature review

More and more data in various formats are integrated into knowledge graphs. However, there is no overview of existing approaches for generating knowledge graphs from heterogeneous (semi-)structured data, making it difficult to select the right one for a certain use case. To support better decision making, we study the existing approaches for generating knowledge graphs from heterogeneous (semi-)structured data relying on mapping languages. In this paper, we investigated existing mapping languages for schema and data transformations, and corresponding materialization and virtualization systems that generate knowledge graphs. We gather and unify 52 articles regarding knowledge graph generation from heterogeneous (semi-)structured data. We assess 15 characteristics on mapping languages for schema transformations, 5 characteristics for data transformations, and 14 characteristics for systems. Our survey paper provides an overview of the mapping languages and systems proposed the past two decades. Our work paves the way towards a better adoption of knowledge graph generation, as the right mapping language and system can be selected for each use case.     

本体驱动的语义Web服务动态复合的研究

传统Web服务的复合由于缺乏足够的语义信息而大大降低了服务复合的效率和准确率。语义Web弥补了传统Web语义不足的缺点。但是,面对语义Web上分布的海量知识,如何有效地利用语义信息实现Web服务复合成为一个迫切需要解决的问题。文章针对这一问题,提出一种基于多维用户模型的动态服务复合机制。该机制在Web服务语义标识的启发下通过语义匹配算法能够实现Web服务的顺序复合和并行复合。采用这种服务复合机制将会在一定程度上提高语义Web服务复合的效率和准确率。     

Web服务组合策略研究及组合决策平台实现

由于关注点的不同和客观环境的多样性,Web服务组合方法的种类纷繁复杂。如何从零碎散乱的不同决策角度出发来构建可行而高效的组合方法,是现阶段Web服务组合研究中亟待解决的关键问题之一。因此,本研究将注意力放在一套可以帮助Web服务组合实践者选择服务组合方法的决策机制上。考虑到层次分析法可以用来帮助解决这个多阶段多标准问题,分析综合了前人的相关研究成果,从而根据层次分析法构建结构树,进而举例详细阐述了如何在多个备选方案中做出最佳选择的Web服务组合决策机制。最后,为帮助Web服务组合实践者理解和使用这套决策机制,也设计并实现了一个决策平台easyWSC,现已开放给相关研究人员和实践者使用、讨论和改进。     

事件驱动的动态服务组合策略在线自适应优化

针对复杂应用环境中网络新媒体服务系统的特点,提出一种事件驱动的动态服务组合策略及其在线优化算法,在保证各类业务服务质量（QoS）的同时,提高系统资源的利用率．通过定义不同类型的事件,驱动服务组合的动态调整,实现对各类业务Qos的保障和对业务需求变化的感知．构建基于半Markov切换空间控制过程的系统分析模型,利用模型的动态结构特点,提出一种结合随机逼近和策略迭代的在线优化算法．该算法不依赖系统参数信息,对环境具有良好的自适应性．仿真实验结果验证了算法的有效性．     

面向阅读理解的句子组合模型

阅读理解任务需要综合运用文本的表示、理解、推理等自然语言处理技术。针对高考语文中文学作品阅读理解的选项题问题,提出了基于分层组合模式的句子组合模型,用来实现句子级的语义一致性计算。首先,通过单个词和短语向量组成的三元组来训练一个神经网络模型;然后,通过训练好的神经网络模型来组合句子向量（两种组合方法：一种为递归方法;另一种为循环方法）,得到句子的分布式向量表示。句子间的一致性利用两个句子向量之间的余弦相似度来表示。为了验证所提方法,收集了769篇模拟材料+13篇北京高考语文试卷材料（包括原文与选择题）作为测试集。实验结果表明,与传统最优的基于知网语义方法相比,循环方法准确率在高考材料中提高了7.8个百分点,在模拟材料中提高了2.7个百分点。     

动态Web服务合成中的服务选择算法研究

为了提高服务合成效率并更好的适应动态变化的应用环境,提出了基于流程修改的服务合成方案,使得复合服务的执行与服务发现过程并行化。提出了基于QoS属性的服务选择算法,该算法能够实现服务执行时选择服务,在考虑综合QoS信息及时间因素的基础上,通过不断更新用户需求来进行服务选择,提高了服务合成效率。实验结果表明,该选择算法可以获得满足用户需求且最优的服务,很好的保证了服务的可靠执行。     

朝向全局式的声明式传感器网络开发模式

探讨一种全局式的声明式传感器网络开发模式,将全局式的声明式网络程序编译为分布式程序,再交给网络节点的虚拟机执行.因此,开发者只需声明网络全局的功能,而无须处理网络的分布式计算过程以及底层细节.     

容错的网络声明式程序

介绍了基于递归规则的网络声明式语言Netlog的语法和分布式不动点语义,定义了强良好的程序,并证明了强良好的程序的计算结果对有限的消息丢失不敏感.     

DENEB: a platform for the development and execution of interoperable dynamic Web processes

Service‐oriented computing provides a suitable technological foundation for developing and executing dynamic business processes. However, most current approaches for composition languages and architectures for dynamic process integration do not provide the flexibility and dynamism required by interorganisational evolving environments. In this work, the DENEB platform for the development and execution of Web processes is presented. DENEB is based on the conversational approach and the Nets‐within‐Nets paradigm, allowing Web processes to acquire and execute new interaction protocols at run‐time. This makes DENEB a well‐adapted and flexible platform for dynamic service composition, interaction and integration, suitable for this kind of scenario. The scalability of the proposed solution is evaluated by means of the development of a set of experiments. Copyright © 2011 John Wiley & Sons, Ltd.     

二元网络服务关系及动态服务组合的研究

动态网格服务组合能在服务运行过程中集成和协同多个服务的功能,因此能解决面向服务应用中的复杂问题。基于二元关系理论,给出了与网格服务关系相关的一些概念。在对以上概念有关性质研究的基础上,提出了任务偏序集驱动的动态服务组合方法。该方法容易实现,仿真实验结果表明该方法的组合效率很高。