Chun-Lung Huang

A Fuzzy Model for Selection of QoS-Aware Web Services

With the increasing popularity of employing Web services, quality of service (QoS) measure of service becomes a significant concern for service consumers and providers. However, current technologies are poor to identify the relative importance of nonfunctional QoS criteria for Web services and they are not fitting well for selecting the appropriate service. In this paper, a new scheme for right selection of QoS-aware of Web services which exploits fuzzy logic to locate and select the right service based on customers preference or satisfaction degree. The aim is to compute both functional and non-functional weightings of QoS criteria and to assist customers to make the right choice for Web services

Reaching consensus: A moderated fuzzy web services discovery method

Web services are used for developing and integrating highly distributed and heterogeneous systems in different domains such as e-business, grid services, and e-government systems. Web services discovery is a key to dynamically locating desired web services across the Internet. Prevailing research trend is to dynamically discover and compose web services in order to develop composite services that provide enhanced functionality. Existing discovery techniques do not take into account the diverse preferences and expectations of service consumers and providers which are generally used for searching or advertising web services. This paper presents a moderated fuzzy web service discovery approach to model subjective and fuzzy opinions, and to assist service consumers and providers in reaching a consensus. The method achieves a common consensus on the distinct opinions and expectations of service consumers and providers. This process is iterative such that further fuzzy opinions and preferences can be added to improve the precision of web service discovery. The proposed method is implemented as a prototype system and is tested through various experiments. Experimental results demonstrate the effectiveness of the proposed method.

Service discovery through multi-agent consensus

Service discovery is one of the key processes for facilitating the automation of service composition. The effectiveness of discovery relies on the appropriateness of descriptions for services and the consensus on the descriptions from participating bodies. However, existing work on service discovery did not address the issues associated with inconsistent understandings on the service descriptions from service providers and consumers. Predefined ontology may not be an appropriate solution in this case, due to its static nature and dynamic environment that Web services are situated. In this paper, we attempt to address this issue by proposing a multiagent consensus approach which is based on fuzzy logic and semantic Web technologies in order to assist service providers and consumers in reaching consensus on their service advertisement and request with consideration of their expectations and preferences. In addition, a user friendly tool for constructing agent based Web service is introduced for assistance in representing users preference and expectations as well as managing Web services.

A fuzzy outranking approach in risk analysis of web service security

Abstract Risk analysis is considered as an important process to identify the known and potential vulnerabilities and threats in the web services security. It is quite difficult for users to collect adequate events to estimate the full vulnerabilities and probability of threats in the Web, due to the rapid change of the malicious attacks and the new computer’s vulnerabilities. In this paper, a fuzzy risk assessment model is developed in order to evaluate the risk of web services in a situation where complete information is not available. The proposed model extends Pseudo-Order Preference Model (POPM) to estimate the imprecise risk based on richness of information and to determine their ranking using a weighted additive rule. A case study of a number of web services is presented in order to test the proposed approach.

Core-based Agent for Service-Oriented Market

The advantages of service-oriented architecture for information systems development have increased its popularity and improved service availability over the Internet. In order to maintain its sustainability and prevent users from exploiting free services, a service-oriented market mechanism should be introduced to regulate the market. However, this issue has not been well addressed in the community. In this work, we propose core-based agents that can collect information from service-oriented markets to convince service providers and consumers to form a coalition based on the core concept solution from game theory. With the introduction of the agent to the service-oriented market, a number of multiple core markets can be merged into a virtual market with a unique core which satisfies the requirements of stability and efficiency. An example of a travel agent web service, which is a composite web service, will be used to illustrate the roles of the agents in this paper.

A sentinel based exception diagnosis in market based multi-agent systems

Market based Multi-agent systems (MAS) operate in an open and dynamic environment where agents enter and leave the system unpredictably. The dynamism and unpredictable nature of an open environment gives rise to unpredictable exceptions. It becomes essential to have some exception diagnosis mechanisms in these systems to effectively manage their exception diagnose processes. The defining characteristic of mechanisms is their ability to provide a uniform exception diagnosis capability to independently developed agents. In this paper we present a brief discussion of our proposed sentinel based approach to exception diagnosis in an open MAS and discuss the accuracy and performance overhead of our approach when applying in a market based MAS.

QoS‐aware mobile service transactions in a wireless environment

Mobile computing greatly facilitates the provision of mobile services using portable and handheld devices which are connected through wireless networks. A pre‐requisite for the provision of an effective service is to ensure quality of service (QoS) during the concurrent execution of requests and system or network failures. This paper presents a new transaction management approach for the provision of mobile services which is based on advanced transaction models and fuzzy selection criteria. It employs a novel QoS consensus moderation approach in order to select preferred mobile services from among various alternatives, thus providing multiple pathways to the completion of mobile service transactions. Unlike traditional transaction management schemes, the proposed approach takes into account QoS attributes in the commit process of mobile service transactions. The proposed approach is implemented as a prototype tool and evaluated through a number of experiments. Experimental results show that the proposed approach effectively selects mobile services and significantly increases the throughput (i.e. commit rate) of mobile service transactions. Copyright

A fuzzy decision model of risk assessment through fuzzy preference relations with users' confidence-interval

Risk assessment for security management is a complex process which linked to substantial ambiguous. However, existing techniques of risk analysis determine the solution by the probability distribution junction of threats and its impact loss. In fact, it is difficult for users to collect precise and adequate events to estimate the probability of threats and impact losses. Consequently, a fuzzy risk analysis model is developed to prioritize the risk ranking of assets. The proposed model uses pseudo-order preference model (POPM) to represent the imprecise preference degree of decision maker and determine the ranking of alternative using fuzzy majority concept. It extends the traditional risk analysis using fuzzy multiple-person decision making (MPDM) theory and POPM to risk analysis in fuzzy environment. Finally, a real case of risk assessment for the internet data center (IDC) is given to illustrate our approach.

Exception Diagnosis for Agent-Oriented Services

Agent oriented architectures and service oriented architectures (SOA) have many features in common such as loose coupling and provision and consumption of services. Software agent systems have been used in many commercial applications due to their attractive attributes such as autonomy, flexibility and a rich and complex set of interaction protocols. Agents in such systems provide and consume services on behalf of their owners. These systems are prone to various kinds of runtime exceptions due to the dynamic nature of open environments and the different programming models involved in the provision of a particular service. Diagnosis of underlying causes of these exceptions is critical for the successful and reliable operation of agent oriented services. This paper presents and discusses a sentinel agent based approach for diagnosing the underlying causes of runtime exception for agent-oriented services.