Trust Brokering and Its Use for Resource Matchmaking in Public-Resource Grids

This paper presents a trust brokering system that operates in a peer-to-peer manner. The network of trust brokers operate by providing peer reviews in the form of recommendations regarding potential resource targets. One of the distinguishing features of our work is that it separately models the accuracy and honesty concepts. By separately modeling these concepts, our model is able to significantly improve the performance. We apply the trust brokering system to a resource manager to illustrate its utility in a public-resource Grid environment. The simulations performed to evaluate the trust-aware resource matchmaking strategies indicate that high levels of ‘robustness’ can be attained by considering trust while matchmaking and allocating resources.Dr Azzedin contributed towards the work in this paper while he was at University of Manitoba, Winnipeg, Canada.     

多主体系统中基于本体论的服务相容匹配机制

利用本体论的表示能力,提出了基于本体论的主体服务匹配机制;通过自定义的领域概念化语言,描述领域概念集合以及概念的分类体系,在此基础上完成对主体服务的描述.以概念相容度为依据,提出主体服务语义相容度的概念,给出了主体服务匹配的策略和算法,并通过一个例子描述了主体服务的匹配过程,讨论了其相关的实现环境.     

Larks: Dynamic Matchmaking Among Heterogeneous Software Agents in Cyberspace

Service matchmaking among heterogeneous software agents in the Internet is usually done dynamically and must be efficient. There is an obvious trade-off between the quality and efficiency of matchmaking on the Internet. We define a language called Larks for agent advertisements and requests, and present a flexible and efficient matchmaking process that uses Larks. The Larks matchmaking process performs both syntactic and semantic matching, and in addition allows the specification of concepts (local ontologies) via ITL, a concept language. The matching process uses five different filters: context matching, profile comparison, similarity matching, signature matching and constraint matching. Different degrees of partial matching can result from utilizing different combinations of these filters. We briefly report on our implementation of Larks and the matchmaking process in Java. Fielded applications of matchmaking using Larks in several application domains for systems of information agents are ongoing efforts.     

Coordinated load management in Peer-to-Peer coupled federated grid systems

This paper proposes a coordinated load management protocol for Peer-to-Peer?(P2P) coupled federated Grid systems. The participants in the system, such as the resource providers and the consumers who belong to multiple control domains, work together to enable a coordinated federation. The coordinated load management protocol embeds a logical spatial index over a Distributed Hash Table?(DHT) space for efficient management of the coordination objects; the DHT-based space serves as a kind of decentralized blackboard system. We show that our coordination protocol has a message complexity that is logarithmic to the number of nodes in the system, which is significantly better than existing broadcast based coordination protocols. The proposed load management protocol can be applied for efficiently coordinating resource brokering services of distributed computing systems such as grids and PlanetLab. Resource brokering services are the main components that control the way applications are scheduled, managed and allocated in a distributed, heterogeneous, and dynamic Grid computing environments. Existing Grid resource brokers, e-Science application work-flow schedulers, operate in tandem but still lack a coordination mechanism that can lead to efficient application schedules across distributed resources. Further, lack of coordination exacerbates the utilization of various resources (such as computing cycles and network bandwidth). The feasibility of the proposed coordinated load management protocol is studied through extensive simulations.     

支持QoS约束的自主单元语义服务匹配

主体服务描述和主体服务匹配是利用主体和多主体系统为用户提供各种有效和高效服务的关键.综合考虑了语义和服务质量对匹配的影响,提出了自主单元主体服务描述模型,并在此基础上重点研究了一种支持QoS约束的自主单元语义服务匹配算法.该算法通过语义相似度匹配和服务质量匹配两个过程,有效获得满足给定语义相似度的阈值,且具有最佳服务质量水平的主体服务.     

The reflective mobile agent paradigm implemented in a smart office environment

Ubiquitous systems will integrate computers invisibly and unobtrusively in everyday objects. Data will be catched from single or multi-sensor devices and will be used for context extraction. New location-based services will be adapted to user preferences. For this the ubiquitous system needs to know user profiles, likings, and habits. As the user moves, these information must be made available at the new location of the user. Either the user carries the data on wearable or portable computers or the smart environment takes responsibility for transporting them. The amount of new devices and services makes an efficient use by centralized systems very difficult. The idea presented in this paper is that a virtual reflection of the user represented by a mobile agent accompanying in the smart environment. Mobile agents offer a possibility to encapsulate information of a person and the person’s preferences and perform location-based services of the ubiquitous system in the name of the user. Security and privacy are major concerns of such an agent system. This paper describes a ubiquitous mobile agent system named UbiMAS which has security extensions to provide high protection of agents and significant personal data. UbiMAS is applied in the smart doorplate project as part of a smart office environment.     

Composing web services enacted by autonomous agents through agent-centric contract net protocol

ContextAgents are considered as one of the fundamental technologies underlying open and dynamic systems that are largely enabled by the semantic web and web services. Recently, there is a trend to introduce the notion of autonomy empowered by agents into web services. However, it has been argued that the characteristics of autonomy will make agents become available intermittently and behave variedly over time, which therefore increase the complexity on devising mechanisms for composing services enacted by autonomous agents.ObjectiveIn this work, we propose an extension to Contract Net protocol, called Agent-centric Contract Net Protocol (ACNP), as a negotiation mechanism with three key features for composing web services enacted by autonomous agents.Method(1) A matchmaking mechanism embedded in a middle agent (as a service matchmaker) for discovering web services that are available intermittently is presented based on the concept of agent roles; (2) A selection algorithm based on risk-enabled reputation model (REAL) embedded in a manager agent (as a service composer) is introduced to serve a basis for selecting web services with variant performance; and (3) A negotiation mechanism between a manager agent and contractor agents (as atomic services) is devised and enables both a service composer and the atomic services to request, refuse or agree on adapting changes of services.ResultsThe problem of assembling a computer is discussed in this paper.ConclusionIt is increasingly recognised that web services would become more autonomous by introducing diverse agent technologies to better constitute more complex systems in open and dynamic environments. As web service technologies are best exploited by composite services, it is imperative to devise mechanisms for composing services of autonomy.     

IBIZA: E-market Infrastructure for Custom-built Information Products

The merger of electronic commerce, intelligent agent and distributed computing technologies over TCP/IP-based platforms enables the creation of electronic markets in new types of products featuring both human and software agents as actors. One such example is a market in custom-built information products. These are information products that have been constructed to meet specific requirements provided by the consumer. Examples include custom research reports, analysis, and computational objects. How should these markets be designed? What are the market mechanisms that should be used to coordinate the interactions between the actors? What should be the decision strategies employed by the software agents that participate in the market? IBIZA is a computational workbench that enables designers to create and simulate electronic markets in information products. It provides a repository of software agents, bidding strategies, brokering strategies and market mechanisms. Using the repository, designers can instantiate particular designs of electronic markets and conduct experiments to study the impact of design decisions on desired objectives. In this paper, we focus on the key technical and economic issues encountered in the design of IBIZA. We illustrate using examples from our work on designing a software agent-based electronic market for automated model development.     

基于策略的Web服务非功能属性匹配

Web服务的非功能属性匹配对增强Web服务发现的准确性,保证Web服务调用质量具有重要作用。目前Web服务的非功能属性匹配研究一般局限于某一具体的非功能属性,缺少支持各非功能属性的统一匹配方法。该文提出了一种基于策略的Web服务非功能属性的匹配方法,把Web服务非功能属性作为服务双方的策略,利用策略匹配来实现非功能属性的匹配。采用WSPL作为策略描述语言,并提出了层次化策略的概念,利用不同的发布方式对不同层次的策略进行发布,服务发现的过程与不同层次的策略匹配结合在一起。该方法支持各种非功能属性的匹配,并可以容易地和Web服务的功能性匹配方法结合到一起,形成完整的Web服务发现匹配系统。     

一个个性化的信息搜集Agent的设计与实现

介绍了一个个性化的信息搜集Agent系统--DOLTRI-Agent(distanceandopenlearningtrainingresourceinformationagent)的设计与实现.DOLTRI-Agent系统是一个远程开放式学习(distanceandopenlearning,简称DOL)的教材信息搜集Agent.它基于多Agent体系结构,包含3个子Agent和其他3个组件.该系统具有主动搜集、维护、更新信息的功能,同时还具有个性化的特点,可不断学习用户知识,包括用户感兴趣的信息领域、用户的使用习惯等,并能运用这些知识来为用户提供个性化的信息服务和操作界面.     

一种基于Agent技术的Web Services匹配模型的研究

Web Services是当前Web应用的一种新的模式。Internet将成为一个真正的分布式的计算平台,其上的服务可以协作完成某一任务,并且Web将成为可编程的。Web Services的发现是很重要的,因此有必要研完Web Services的匹配。在本文中,我们提出了一种基于Agent的Web Services的两层次匹配模型。     

A novel non-functional matchmaking approach between fuzzy user queries and real world web services based on rough sets

We propose in this paper a novel matchmaking approach between fuzzy user queries and real world Web services. The matchmaking spans over a domain dependent classification step that produces fuzzy classification rules for Web services. The elaborated rules leverage a core set of non-functional quality attributes, which is extracted using rough sets theory. Furthermore, these rules are leveraged to classify Web services into categories, which allows reducing the matchmaking space. The experimental results show that our proposed matchmaking approach provides good results in terms of efficiency and precision.     

PLANGENT: an approach to making mobile agents intelligent

Network environments give computer users the option of employing distributed information and services to complete a task. However, gathering information and using services distributed in networks requires knowing exactly what kinds of information and services are required for a task, where they are, and how they can be obtained or utilized. Tracking down the answers to these questions can be difficult, time consuming tasks for users. Mobile agent technology is expected to release them from having to do so. Instead, “intelligent” mobile agents will comprehend the user's requirements, search network nodes autonomously for appropriate information and services, and return with the answers. But several problems must be solved before we can expect agents to perform such actions effectively. We focus on the question of intelligence as a prerequisite for agent functions. What sort of intelligence is expected of agents? We have adopted a model based on the ability to make flexible plans. Specifically, we think mobile agents must be able to: understand user requirements; plan actions that will satisfy the requirements act according to the plan; modify the plan according to actual conditions when they differ from those initially expected; and execute the modified plan. We have implemented these functions in the Plangent system and validated their effectiveness in several example applications. We describe how we combined these planning functions with mobile agent facilities, and show how the agents behave intelligently in an example application of personal travel assistance     

Process-context aware matchmaking for web service composition

Web service composition can help software developer design more powerful and flexible applications according to requirements of enterprise. But during compositing, how to discover suitable web services is a critical problem in design and implementing application-oriented web service technologies. The traditional keyword-based matchmaking approach is difficult to help developer to find suitable service. Current researches find that to attaching semantics to each registered service can help improve the precision of matchmaking. The improvement can help developer find more suitable service for business process. This paper proposes a novel approach of semantics-based matchmaking, which is named process-context aware matchmaking. The process-context aware matchmaking discovers the suitable service during web service composite modeling. During matchmaking, the approach utilizes not only semantics of technical process but also that of business process of a registered service, thus further improving the precision of matchmaking. We integrate the process-context aware matchmaking with business-process-driven web service composition in an integrated development environment based on Eclipse. The performance evaluation shows that performance overhead of this novel approach is acceptable.     

Trust ontologies for e‐service environments

In this article, we introduce trust ontologies. An ontology represents a set of concepts that are commonly shared and agreed to by all parties in a particular domain. Here, we introduce generic and specific trust ontologies. These ontologies include the following: an agent trust ontology and trustworthiness; agents include sellers, service providers, Web sites, brokers, shops, suppliers, buyers, or reviewers. A services trust ontology and trustworthiness assists in measuring the quality of service that agents provide in the service‐oriented environment such as sales, orders, track and trace, warehousing, logistics, education, governance, advertising, entertainment, trading, online databases, virtual community services, security, information services, opinions, and e‐reviews. A goods or products trust ontology and trustworthiness is useful for measuring the quality of products such as commercial products, information products, entertainment products, or second‐hand products. We present a trust ontology that is suitable for all types of agents that exist in the service‐oriented environment. As agent trust is measured through the quality of goods and services, we introduce two additional distinct concepts of service trust ontology and product trust ontology. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 519–545, 2007.