Publications

 Being a successful technique in software practice, Object Orientation (OO) is a hot topic in academic research fields. Among many formalisms, rCOS, a refinement calculus of object-oriented systems based on Unifying Theories of Programming (UTP), has been proven a promising one in the sense of its applications to incremental software constructions, the formal use of UML, etc. However, equipped with a semantics reasoning on both static and dynamic properties, rCOS is not designed for static checking. We believe introducing static checking will extend the power of rCOS. In this paper, we develop a type system for rCOS and prove some type safety theorems. To make the theoretical results of this paper convincible and easy to be understood, we follow the traditional approaches of type systems construction. That is, we use an operational semantics as the basic explanation of rCOS language in spite of the fact that rCOS is originally developed in a denotational framework.

 Business Process Execution Language (BPEL), or Web Services BPEL (WS-BPEL), is the standard for specifying workflow process definition using web services. Research on formal modelling and verification of BPEL has largely concentrated on control flow and data flow, while security related properties have received little attention. In this work, we present a formal framework that integrates Role Based Access Control (RBAC) into BPEL and allows us to express authorisation constraints using temporal logic. Using this framework, we show how model-checking can be applied to verify that a given BPEL process satisfies the security constraints.

Being a successful technique in software practice, object orientation (OO) is a hot topic in academic research fields. Among many formalisms, rCOS, a refinement calculus of object-oriented systems based on unifying theories of programming (UTP), has been proven a promising one in the sense of its applications to incremental software constructions, the formal use of UML, etc. However, equipped with a semantics reasoning on both static and dynamic properties, rCOS is not designed for static checking. We believe introducing static checking will extend the power of rCOS. In this paper, we develop a type system for rCOS and prove some type safety theorems. To make the theoretical results of this paper convincible and easy to be understood, we follow the traditional approaches of type systems construction. That is, we use an operational semantics as the basic explanation of rCOS language in spite of the fact that rCOS is originally developed in a denotational framework.