|Models and Technologies for e-Service Composition
|Luciano Baresi, Maristella Matera, Pierluigi Plebani - Politecnico di Milano
December 15, morning
Models and Technologies for e-Service Composition
Rationale and Aims
Nowadays, Internet is more and more perceived not only as content provider, but also as service provider. For this reasons, much emphasis is currently posed on e-service oriented applications, which enable the provisioning of platform-independent solutions. Due to the strong interest coming from the major ICT players, a number of models and languages have been recently proposed for the description, composition, and retrieval of e-services, according to the SOA (Service Oriented Architecture) conceptual framework, which addresses three main actors: the service provider, the service directory, and the service requester.
The aim of this tutorial is to provide participants with a systematic view of the models and technologies to describe basic services and compose them to augment their functionality with security and interaction capabilities and deliver (complete) processes. The presentation of the different solutions will be based on a reference model, which will allow us to highlight the relationships among the different proposals (e.g., BPEL4WS, WSCI, DAML-S, WSXL, WS security, PSML, ebXML, WS-I) , and compare supported functionality.
A basic knowledge of Internet and Web technologies is required. Knowledge about XML, XSD and SOAP is suggested.
The tutorial will be organized along two parts. The first part will illustrate the rationale behind e-service composition and will provide a general overview of the existing solutions with respect to the adopted reference model. The second part will describe each solution in details.
Part 1 – General Overview
- Requirements for e-service composition
- Basic concepts behind the provision and invocation of e-services
Part II – Models and Languages for Composition of e-services
- Known approaches to e-service composition
- A reference model for the composition of e-services
- Composition to add interactivity and security
- e-services composition and orchestration
- Semantics-oriented composition
- Analysis and validation
|Interoperability in the B2B E-Commerce Era: Issues and Enabling Technologies
|Boualem Benatallah - University of New South Wales, Sydney, Australia
December 15, afternoon
Interoperability in the B2B E-Commerce Era: Issues and Enabling Technologies
Rationale and Aims
The objective of this tutorial is to (i) discuss the issues of interoperability in B2B EC, (ii) present a framework that may be used to study B2B integration solutions, and (iii) provide a comprehensive overview of enabling technologies. Interoperability among loosely coupled and tightly coupled systems has been an active research over the past 20 years in several areas including databases, programming languages, knowledge-based systems, and digital libraries. In terms of related work, there have been several surveys on interoperability in different areas. These surveys, however, are mostly focused on specific topics (e.g., databases). While relevant to interoperability in B2B EC, the work covered in those surveys does not focus on B2B EC requirements.
A wide range of technologies have emerged over the past few years that need to be analyzed against EC interoperability requirements. Indeed, today's EC systems are complex assembly of Web servers, databases, legacy applications, ERPs, middleware and networking services, etc.
The tutorial goals are to:
1. Introduce the field of electronic commerce, main functions (e.g., business process management, content management, communication among customers, providers, and partners) of an EC system, EC business models, and evolution of EC systems. The purpose is not to provide a complete anatomy of an EC system, but to illustrate the relevance of interoperability at different layers of a B2B EC system.
2. Identify and illustrate the layers where interoperability issues enter into the constituent system functions. We will study interoperability issues at the communication, content, and business process layers. From a system perspective, the activities of an EC transaction can be supported by several functions including business process management (i.e, collaborative activities among customers, providers, and partners such as negotiation, order fulfillment, etc.), content management (i.e, storage, search, organisation, etc.), communication among the parties involved in the transaction (i.e, customers, providers, and partners). The objective of interoperability at communication layer is to achieve a complete independence from protocols. The objective of interoperability at content layer is to achieve a complete independence of data formats, data models, and languages. The objective of interoperability at the business process layer is to allow autonomous and heterogeneous EC partners to come online, advertise their terms and capabilities, and engage in peer-to-peer interactions with any other EC partners. Consider a simple example of a company A purchasing a product from another company B. After discovering a match between their businesses, the two companies A (the buyer) and B (the seller) need to negotiate and agree on the joint business process (i.e, delivery mode, contracts, etc.) Then, the company A needs to know what product to buy and send a purchase order to the company B. This involves the creation and manipulation of business information (e.g., a purchase order document, product description). The information content and representation depends on the involved systems. Finally, there must be a way to communicate the messages that contain requests and business information between the companies A and B.
3. Identify and illustrate the fundamental dimensions that may be used to study the interoperability issues and evaluate B2B EC interoperability solutions. There may be many dimensions, but we consider the following as the most important for B2B EC: Coupling among partners, Heterogeneity, Autonomy, External Manageability, Scalability, Adaptability, Security, and Reliability. While these dimensions cannot be used to quantitatively evaluate B2B EC interoperability solutions, they can help to provide useful criteria for assessing them against the B2B integration requirements.
4. Review several relevant B2B integration approaches including component-based middleware (e.g., CORBA/Java based solutions, Enterprise Application Integration suites), inter-enterprise workflows, and Web service technologies (e.g., SOAP, WSDL, UDDI, BPEL4WS, WSCI, and ebXML). We also look the role of B2B integration standards (e.g., RosettaNet, cXML, EDI) in providing support for handling document and business process semantic heterogeneity. These approaches will be evaluated with regard to the B2B interoperability layers and dimensions. Each solution is relevant to one or several layers. For instance, EDI standards provide support for interoperability at the communication and content layers. It is worth noting that interoperability is better supported at the communication layer than the content and business process layers. The main reason is that the content and business layers require semantic interoperability (e.g., the understanding of the semantic of EC partner business processes). The existing approaches exhibit wide variation in their tradeoffs with regard to the previous dimensions. For example, approaches that rate high with regard to the autonomy, may rate low with regard to external manageability.
5. Review some research prototypes and commercial web application platforms (e.g., BEA WebLogic Integrator, IBM Websphere, Microsoft .Net, and WebMethods B2B integration solutions) as case studies. These systems will be evaluated with regard to the B2B interoperability layers and dimensions.
6. Discuss several open research issues in building B2B integration solutions. We show that each approach makes specific tradeoffs with regard to the set of evaluation criteria and is thus appropriate in different circumstances. We also show that some of the unique requirements (i.e, fast and dynamic integration of services, dependable integration, semantic interoperability at the business process layer) of B2B applications are beyond the capabilities of current technologies.
The targeted audience of this tutorial include practitioners interested in B2B integration solutions, researchers and students interested doing research in B2B EC, Web data and service integration.
The tutorial length is 3 hours.
1. Background: introduction to the field of interoperability in the B2B EC era.
2. B2B E-Commerce: models, architectures, and systems.
3. Integration Layers in B2B EC Systems: communication, content, and business process layers.
4. Evaluation of B2B integration solutions: illustrate the fundamental dimensions (i.e., Coupling among partners, Heterogeneity, Autonomy, External Manageability, Scalability, Adaptability, Security, etc.) that may be used to study B2B EC integration solutions.
5. B2B integration solutions: integrated e-catalogs, component-based middleware, Web service technologies, inter-enterprise workflows, and B2B integration standards.
6. Research efforts.
7. Commercial Web application development platforms.
8. Summary and Conclusions.