Rules are used to express computational or business logic in the information systems which do not have explicit control flow, so rules are more suitable for execution in the dynamic situations for business collaborations. Along with the rapid development of the Web, multiparty collaborations for carrying out busi-ness services in this environment are more significant than ever before. For ex-ample, when a credit card transaction is requested from a merchant, a customer needs a payment authorization from the merchant and the card issuer (the bank) to accomplish a successful transaction service. In this case, both merchant and bank have their own policies as rules to conduct their authorization processes.
If both parties are required to combine their policies, we hope they can trans-form the rules into a trans-formal common rule trans-format, such as RIF. For example, rules from the bank are directly imported by the merchant and processed with his local rule engine to derive an authorization decision. In addition, this situation can be extended to other relevant web services for conducting composite web services.
Another use case is a seller, posting his price discount and refund policies for execution as rules on his website, to attract potential customers for making a purchase decision from his selling goods. Moreover, a vendor advertises his lead time policies in formal rules to attract customers and also as a part of contract negotiation in the supply chain management.
Use cases such as the ones we have shown above are categorized by the W3C RIF Working Group as a type of policy-based transaction authorization policy for access control with the interchange of human-oriented business rules. Several other interesting use cases focusing on different application domains are also available on this website32. Another interesting use case study was proposed by the Business Rule Group (BRG) to use SBVR for illustrating business rule concepts of EU-Rent, EU-Fly, and EU-Stay. They are available on the BRG website33. The challenge here is whether we have enough use cases that can be accomplished by current rule systems on the Web to convince people to adopt and use this technology.
7 Conclusion
In this study, we outlined the objectives of RuleML-Challenge competitions started in 2007. Alos, we have elaborated the possible research and implemen-tation challenges for rule systems on the Web that are closely related to the Challenge competition events in the forthcoming years.
The first challenge is to perfectly implement rule systems with the data model, either from a relational or object-oriented database or from a DL-based knowledge base. The second challenge is to enable computerized policies, created in a policy language that is compliant with human legal regulations. In addition
32http://www.w3.org/2005/rules/wg/wiki/Use Cases
33http://www.businessrulesgroup.org/egsbrg.shtml
to the legalized policy implementation with policies created from the policy lan-guage, computerized policy can be shown as a combination of ontology and/or rule languages for the purpose of information sharing and web service execu-tion. The third challenge is full awareness of current available commercial and open source rule management systems and, moreover, finding out the pros and cons of each rule system by a standard evaluation benchmark to verify its scal-ability and performance. The fourth challenge is to achieve rule interoperscal-ability using available rule interchange languages for rules created and distributed on the Web. The fifth challenge is to demonstrate sufficient use cases implemented from rule systems, while interchanging their rules through one of rule interchange language.
Acknowledgements
This research was partially supported by the NSC Taiwan under Grant No. NSC 95-2221-E004-001-MY3 and NSC 98-2918-E-004-003.
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