Xumin Liu

Deploying and managing Web services: issues, solutions, and directions

Web services are expected to be the key technology in enabling the next installment of the Web in the form of the Service Web. In this paradigm shift, Web services would be treated as first-class objects that can be manipulated much like data is now manipulated using a database management system. Hitherto, Web services have largely been driven by standards. However, there is a strong impetus for defining a solid and integrated foundation that would facilitate the kind of innovations witnessed in other fields, such as databases. This survey focuses on investigating the different research problems, solutions, and directions to deploying Web services that are managed by an integrated Web Service Management System (WSMS). The survey identifies the key features of a WSMS and conducts a comparative study on how current research approaches and projects fit in.

Efficient agglomerative hierarchical clustering

An efficient hybrid hierarchical clustering is proposed based on agglomerative method.It performs consistently with different distance measures.It performs consistently on data with different distributions and sizes. Hierarchical clustering is of great importance in data analytics especially because of the exponential growth of real-world data. Often these data are unlabelled and there is little prior domain knowledge available. One challenge in handling these huge data collections is the computational cost. In this paper, we aim to improve the efficiency by introducing a set of methods of agglomerative hierarchical clustering. Instead of building cluster hierarchies based on raw data points, our approach builds a hierarchy based on a group of centroids. These centroids represent a group of adjacent points in the data space. By this approach, feature extraction or dimensionality reduction is not required. To evaluate our approach, we have conducted a comprehensive experimental study. We tested the approach with different clustering methods (i.e., UPGMA and SLINK), data distributions, (i.e., normal and uniform), and distance measures (i.e., Euclidean and Canberra). The experimental results indicate that, using the centroid based approach, computational cost can be significantly reduced without compromising the clustering performance. The performance of this approach is relatively consistent regardless the variation of the settings, i.e., clustering methods, data distributions, and distance measures.

Ev-LCS: A System for the Evolution of Long-Term Composed Services

We propose a system, called EVolution of Long-term Composed Services (Ev-LCS), to address the change management issues in long-term composed services (LCSs). An LCS is a dynamic collaboration between autonomous web services that collectively provide a value-added service. It has a long-term commitment to its users. We first present a formal model, which provides the grounding semantics to support the automation of change management. We present a set of change operators that allow to specify a change in a precise and formal manner. We then propose a change enactment strategy that actually implements the changes. We develop a prototype system for the proposed Ev-LCS to demonstrate its effectiveness. We also conduct an experimental study to assess the performance of the change management approach.

Managing Top-down Changes in Service-Oriented Enterprises

A Service Oriented Enterprise (SOE) provides an efficient and flexible platform where multiple Web services can cooperate together to provide a value-added service. Change management is one of the fundamental issues in enabling SOEs. In this paper, we propose a framework that facilitates in automatically managing top-down changes in SOEs. We start with formalizing a SOEs schema since it is a central concept for specifying and managing top-down changes in SOEs. We then propose a change model as a guide to react to changes. Algorithms are proposed to implement changes by refining a SOEs behavior.

End-to-End Service Support for Mashups

We propose a service-oriented approach to generate and manage mashups. The proposed approach is realized using the Mashup Services System (MSS), a novel platform to support users to create, use, and manage mashups with little or no programming effort. The proposed approach relieves users from programming-intensive, error-prone, and largely nonreusable output process for creating and maintaining mashups. We describe the overall design of MSS and discuss and evaluate its main enabling technologies.

Efficient change management in long-term composed services

We present an efficient framework for managing changes in Long-term Composed Services (LCSs). Because we assume LCSs outsource their functionality from autonomous third-party Web service providers, there is a need to select the best Web service replacements when changes are induced at the LCS level. We propose a framework where managing changes in LCSs is modeled as a dual service query optimization process. In the first phase, reputation is used as a trust mechanism to weed out those Web services that do not exhibit acceptable reputation. In the second phase, the non-functional requirements represented in and by the Quality of Web Service (QoWS) are used to further narrow down the set of reputable Web services to those that also best adhere to the QoWS requirements.

A service computing manifesto: the next 10 years

Mapping out the challenges and strategies for the widespread adoption of service computing.

Semantic Support for Adaptive Long Term Composed Services

We propose an integrated framework that manages changes in long term composed services. The main procedure of change reaction is presented. One of the most challenging research issues of change management is how to automate the process of change reaction. To address this issue, we propose a semantic support, which centers around a tree-structured Web service ontology. The ontology is expected to provide sufficient semantic for change reaction. We propose a set of algorithms for efficiently querying semantics from the ontology. We conduct a set of experiments to evaluate the performance of the proposed algorithms.

Automatic Abstract Service Generation from Web Service Communities

The concept of abstract services has been widely adopted in service computing to specify the functionality of certain types of Web services. It significantly benefits key service management tasks, such as service discovery and composition, as these tasks can be first applied to a small number of abstract services and then mapped to the large scale actual services. However, how to generate abstract services is non-trivial. Current approaches either assume the existence of abstract services or adopt a manual process that demands intensive human intervention. We propose a novel approach to fully automate the generation of abstract services from a service community that consists of a set of functionally similar services. A set of candidate outputs are first discovered based on predefined support ratio, which determines the minimum number of services that produce the outputs. Then, the matching inputs are identified to form the abstract services. We propose a set of heuristics to effectively prune a large number of candidate abstract services. An comprehensive experimental study on real world web service data is conducted to demonstrate the effectiveness and efficiency of the proposed approach.

Service-Centric Framework for a Digital Government Application

This paper presents a service-oriented digital government infrastructure focused on efficiently providing customized services to senior citizens. We designed and developed a Web Service Management System (WSMS), called WebSenior, which provides a service-centric framework to deliver government services to senior citizens. The proposed WSMS manages the entire life cycle of third-party web services. These act as proxies for real government services. Due to the specific requirements of our digital government application, we focus on the following key components of WebSenior: service composition, service optimization, and service privacy preservation. These components form the nucleus that achieves seamless cooperation among government agencies to provide prompt and customized services to senior citizens.