Kunal Verma

Meteor-s web service annotation framework

The World Wide Web is emerging not only as an infrastructure for data, but also for a broader variety of resources that are increasingly being made available as Web services. Relevant current standards like UDDI, WSDL, and SOAP are in their fledgling years and form the basis of making Web services a workable and broadly adopted technology. However, realizing the fuller scope of the promise of Web services and associated service oriented architecture will requite further technological advances in the areas of service interoperation, service discovery, service composition, and process orchestration. Semantics, especially as supported by the use of ontologies, and related Semantic Web technologies, are likely to provide better qualitative and scalable solutions to these requirements. Just as semantic annotation of data in the Semantic Web is the first critical step to better search, integration and analytics over heterogeneous data, semantic annotation of Web services is an equally critical first step to achieving the above promise. Our approach is to work with existing Web services technologies and combine them with ideas from the Semantic Web to create a better framework for Web service discovery and composition. In this paper we present MWSAF (METEOR-S Web Service Annotation Framework), a framework for semi-automatically marking up Web service descriptions with ontologies. We have developed algorithms to match and annotate WSDL files with relevant ontologies. We use domain ontologies to categorize Web services into domains. An empirical study of our approach is presented to help evaluate its performance.

Constraint driven Web service composition in METEOR-S

Creating Web processes using Web service technology gives us the opportunity for selecting new services, which best suit our need at the moment. Doing this automatically requires us to quantify our criteria for selection. In addition, there are challenging issues of correctness and optimality. We present a constraint driven Web service composition tool in METEOR-S, which allows the process designers to bind Web services to an abstract process, based on business and process constraints and generate an executable process. Our approach is to reduce much of the service composition problem to a constraint satisfaction problem. It uses a multiphase approach for constraint analysis. This work was done as part of the METEORS framework, which aims to support the complete lifecycle of semantic Web processes.

Ontology alignment for linked open data

The Web of Data currently coming into existence through the Linked Open Data (LOD) effort is a major milestone in realizing the Semantic Web vision. However, the development of applications based on LOD faces difficulties due to the fact that the different LOD datasets are rather loosely connected pieces of information. In particular, links between LOD datasets are almost exclusively on the level of instances, and schema-level information is being ignored. In this paper, we therefore present a system for finding schema-level links between LOD datasets in the sense of ontology alignment. Our system, called BLOOMS, is based on the idea of bootstrapping information already present on the LOD cloud. We also present a comprehensive evaluation which shows that BLOOMS outperforms state-of-the-art ontology alignment systems on LOD datasets. At the same time, BLOOMS is also competitive compared with these other systems on the Ontology Evaluation Alignment Initiative Benchmark datasets.

Framework for Semantic Web Process Composition

Web services have the potential to revolutionize e-commerce by enabling businesses to interact with each other on the fly. To date, however, Web processes using Web services have been created mostly at the syntactic level. Current composition standards focus on building processes based on the interface description of the participating services. This rigid approach, with its strong coupling between the process and the interface of the participating services, does not allow businesses to dynamically change partners and services. As shown in this article, Web process composition techniques can be enhanced by using semantic process templates to capture the semantic requirements of the process. The semantic process templates act as configurable modules for common industry processes maintaining the semantics of the participating activities, control flow, intermediate calculations, and conditional branches, and exposing them in an industry-accepted interface. The templates are instantiated to form executable processes according to the semantics of the activities in the templates. The use of ontologies in template definition allows much richer description of activity requirements and a more effective way of locating services to carry out activities in the executable Web process. Discovery of services considers not only functionality, but also the quality of service (QoS) of the corresponding activities. This unique approach combines the expressive power of present Web service composition standards with the advantages of Semantic Web techniques for process template definition and Web service discovery. The prototype implementation of the framework for building the templates carries out Semantic Web service discovery and generates the processes.

Semantic WS-agreement partner selection

In a dynamic service oriented environment it is desirable for service consumers and providers to offer and obtain guarantees regarding their capabilities and requirements. WS-Agreement defines a language and protocol for establishing agreements between two parties. The agreements are complex and expressive to the extent that the manual matching of these agreements would be expensive both in time and resources. It is essential to develop a method for matching agreements automatically. This work presents the framework and implementation of an innovative tool for the matching providers and consumers based on WS-Agreements. The approach utilizes Semantic Web technologies to achieve rich and accurate matches. A key feature is the novel and flexible approach for achieving user personalized matches.

Dynamic Workflow Composition: Using Markov Decision Processes

The advent of Web services has made automated workflow composition relevant to Web-based applications. One technique that has received some attention for automatically composing workflows is AI-based classical planning. However, workflows generated by classical planning algorithms suffer from the paradoxical assumption of deterministic behavior of Web services, then requiring the additional overhead of execution monitoring to recover from unexpected behavior of services due to service failures, and the dynamic nature of real-world environments. To address these concerns, we propose using Markov decision processes (MDPs) to model workflow composition. To account for the uncertainty over the true environmental model, and for dynamic environments, we interleave MDP-based workflow generation and Bayesian model learning. Consequently, our method models both the inherent stochastic nature of Web services and the dynamic nature of the environment. Our algorithm produces workflows that are robust to non-deterministic behaviors of Web services and that adapt to a changing environment. We use a supply chain scenario to demonstrate our method and provide empirical results.

Enhancing web services description and discovery to facilitate composition

Web services are in the midst of making the transition from being a promising technology to being widely used in the industry. However, most efforts to use Web services have been manual, thus slowing down the ever changing and dynamic businesses of today. In this paper, we contend that more expressive descriptions of Web services will lead to greater automation and thus provide more agility to businesses. We present the METEOR-S front-end tools for source code annotation and semantic Web service description generation. We also present WSDL-S, a language created for incorporating semantic descriptions in the industry wide accepted WSDL, by extending WSDL 2.0.

Semantic Interoperability of Web Services - Challenges and Experiences

With the rising popularity of Web services, both academia and industry have invested considerably in Web service description standards, discovery, and composition techniques. The standards based approach utilized by Web services has supported interoperability at the syntax level. However, issues of structural and semantic heterogeneity between messages exchanged by Web services are far more complex and crucial to interoperability. It is for these reasons that we recognize the value that schema/data mappings bring to Web service descriptions. In this paper, we examine challenges to interoperability; classify the types of heterogeneities that can occur between interacting services and present a possible solution for data mediation using the mapping support provided by WSDL-S, the extensibility features of WSDL and the popular SOAP engine, Axis 2

Discovery of Web services in a federated registry environment

The potential of a large scale growth of private and semi-private registries is creating the need for an infrastructure which can support discovery and publication over a group of autonomous registries. Recent versions of UDDI have made changes to accommodate interactions between distributed registries. In this paper, we discuss METEOR-S Web service Discovery Infrastructure, which provides an ontology-based infrastructure to access a group of registries that are divided based on business domains and grouped into federations. We also discuss how Web service discovery is carried out within a federation.

Semantics to energize the full services spectrum

Using an ontological approach to better exploit services at the technical and business levels.