Decidability and Complexity of Web Service Business Protocol Synthesis

Automatic synthesis of web services business protocols (BPs) aims at solving algorithmically the problem of deriving a mediator that realizes a BP of a target service using a set of specifications of available services. This problem, and its variants, gave rise to a large number of fundamental research work over the last decade. However, existing works considered this problem under the restriction that the number of instances of an available service that can be involved in a composition is bounded by a constant [Formula: see text] which is fixed a priori. This paper investigates the unbounded variant of this problem using a formal framework in which web service BPs are described by means of finite state machines (FSM). We show that in this context, the protocol synthesis problem can be reduced to that of testing simulation preorder between an FSM and an (infinitely) iterated product of FSMs. Existing results regarding close decision problems in the context of the so-called shuffle languages are rather negative and cannot be directly exploited in our context. In this paper, we develop a novel technique to prove the decidability of testing simulation in our case of interest. We provide complexity bounds for the general protocol synthesis problem and identify two cases of particular interest, namely loop-free target services and hybrid states-free component services, for which protocol synthesis is shown to be respectively NP-COMPETE and EXPTIME-COMPLETE.

Serving on Organizational Boards: What Nurses Need to Know

If you have ever thought about serving on a board or being actively involved in meetings aimed at making policy decisions, but are not sure you have the knowledge, skills or abilities to serve competently, this article is for you! In this article, the authors describe six competencies needed by nurses who are serving on boards and/or policy committees so as to contribute in a productive manner. These competencies include a professional commitment to serving on a governing board; knowledge about board types, bylaws, and job descriptions; an understanding of standard business protocols, board member roles, and voting processes; a willingness to use principles for managing and leading effective and efficient board meetings; an appreciation for the ethical and legal processes for conducting meetings; and the ability to employ strategies for maintaining control during intense/uncivil situations. They also discuss strategies for demonstrating these competencies and describe personal responsibilities of board members. The authors conclude that a knowledge of these rules and standards is essential in order for nurses to assume leadership roles that will enhance the health of today’s and tomorrow’s societies.

Architecture Support for Flexible Business Chain Integration Using Protocol Adaptors

Business chains increasingly rely on the dynamic integration of business processes of different partners. The interaction constraints that result from the business processes are captured in business protocols. Since the business protocols of each partner support its own way of working, the business protocols can easily mismatch, which hinders organizations from forming a business chain. Such mismatches can be resolved by protocol adaptors. In this paper, we show how protocol adaptors can be used to enable the flexible formation of business chains. For different types of business chains, we present formation cases that describe which partners are responsible for the construction and operation of protocol adaptors. Next, we present for each formation case an accompanying concrete software architecture that realizes the case. The presented software architectures support the flexible formation of business chains and use protocol adaptation as a key component. We show the feasibility of the approach by discussing a prototype implementation, which we apply to a case study from the healthcare domain.

From Implicit to Explicit Transitions in Business Protocols

Modeling Web services is a major step towards their automated analysis. One of the important parameters in this modeling, for the majority of Web services, is the time. A Web service can be presented by its behavior which can be described by a business protocol representing the possible sequences of message exchanges. To the best of the authors’ knowledge, automated analysis of timed Web services (e.g., compatibility and replaceability checking) is very difficult and in some cases it is not possible with the presence of implicit transitions (internal transitions) based on time constraints. The semantics of the implicit transitions is the source of this difficulty because most of well-known modeling tools do not express this semantics (e.g., epsilon transition on the timed automata has a different semantics). This paper presents an approach for converting any protocol containing implicit transitions to an equivalent one without implicit transitions before performing analysis.

TIMED PRIVACY-AWARE BUSINESS PROTOCOLS

Web services privacy issues have been attracting more and more attention in the past years. Since the number of Web services-based business applications is increasing, the demands for privacy enhancing technologies for Web services will also be increasing in the future. In this paper, we investigate an extension of business protocols, i.e. the specification of which message exchange sequences are supported by the web service, in order to accommodate privacy aspects and time-related properties. For this purpose we introduce the notion of Timed Privacy-aware Business Protocols (TPBPs). We also discuss TPBP properties can be checked and we describe their verification process.