Jianmin Jiang

Message Dependency-Based Adaptation of Services

Mismatch patterns capture the possible differences between two service (business) protocols to adapt. For these mismatches, formal definitions are presented in this paper. And a novel technique provides support for adapting two or more services. This technique requires that messages and message dependencies are used to directly model service (business) protocols and form a novel model, called a\emph{protocol structure}. Unlike most of existing approaches that only consider typical mismatches (e.g. deadlock), this model is easily used to detect multiple mismatches at a time and to automatically generate BPEL adapters.

Modeling and analyzing mixed communications in service-oriented trustworthy software

Communication is an essential part of service-oriented trustworthy software. The actual communication mechanism among services adopts asynchronous communications and supports broadcast communications. However, in order to achieve a better performance in analysis and verification, most existing formal languages rely on the strong hypothesis: the communication between services is synchronous. In this paper, we propose a novel model, which can model synchronous communications, asynchronous communications and broadcast communications in a uniform way. Moreover, we investigate the preservation problem of the weak termination and deadlocks of a composite service under the hierarchical communication models.

Configuring business process models

A configurable business process model (sometimes referred to as a reference business process model) may be configured to meet the specific requirements of an organization. The configuration activity is required to automatically determine the variability of a configurable process model and ensure the correctness of a specific process model. However, few approaches solve the problem. In this paper, we propose an innovative approach for automatically separating a configurable process model into atomic and correct sub-process models (sub-process models without abnormal behavioral problems). The atomic sub-process models that fulfill specific requirements are merged into specific process models that are provided for organizations. Compared with existing approaches, since the configuration activity is incorporated into the verification process of a process model at design time and can obtain all feasible configurations, our approach avoids independently handling the configuration activity and does not suffer from computational complexity. Moreover, our approach is language-independent. We have developed a prototype tool for configuring these process models.

Analyzing Event-Based Scheduling in Concurrent Reactive Systems

The traditional research on scheduling focuses on task scheduling and schedulability analysis in concurrent reactive systems. In this article, we dedicate ourselves to event-based scheduling. We first formally define an event-based scheduling policy and propose the notion of the correctness of a scheduling policy in terms of weak termination. Then we investigate the correctness of the decomposition of scheduling controls and finally obtain a decentralized scheduling method. The method can automatically decompose the scheduling policies of a concurrent reactive system into atomic scheduling policies. Every atomic scheduling policy corresponds to one subsystem. Each of the subsystems is a completely independent system, which may be developed and deployed independently. An experiment demonstrates these results that may help engineers to design correct and efficient schedule policies for a concurrent reactive system.

Configuration of Services Based on Virtualization

Virtualization is fundamental to cloud computing. It allows abstraction centred on services and isolation of lower level functionalities and underlying hardware. Modeling, analyzing and verifying cloud systems necessarily involve virtualization and services. However, there exist few efforts to effectively formalizing virtualization in cloud computing. In this paper, based on services we present an approach for defining virtualization. We discuss some properties of service virtualization under some operations and the correctness of virtual services (virtual services without abnormal behavioral problems). Moreover, we investigate automatic configuration of a service based on virtualization, that is, given a virtualized service, how can we automatically obtain all possible correct virtual services of such a service? The configuration process is to first separate a virtualized service into atomic and correct virtual services and then merge these atomic virtual services into all possible correct virtual services of such a virtualized service. The obtained theoretical results help to formally analyze, verify and configure cloud systems.

Service Adaptation at Message Level

In SOA, adaptation techniques aim to automatically generate adapters. However, the generation of the adapter is a complicated task and requires extra knowledge to resolve all kinds of mismatches. We propose a novel model, called a protocol structure, which is used to model services and adapters and detect the mismatches among services. Once developers present interface mappings among services, adapters can be derived from the interface mappings.

Symmetry and Autobisimulation

For event structures as a major branch of concurrent models, no one notices their symmetries. It is very likely that someone thinks that symmetry reduction over an event structure can be replaced by the (largest) autobisimulation reduction. We show that, given an event structure, there are some differences between the symmetric quotient model induced by symmetry reduction and the bisimilar quotient model induced by the (largest) autobisimulation. The former is ( interleaving ) bisimulation equivalent and pomset trace equivalent to the original event structure. However, though the latter is bisimulation equivalent to the original, it and its original event structure are not likely pomset trace equivalent.

Symmetry in Process Algebra

An original notion of symmetry for process algebra is defined, which is based on permutation groups. Given a process which is regarded as a structure and a permutation group on it, the quotient process (reduced process) is showed to be interleaving trace equivalent and interleaving bisimulation equivalent to the original process. Furthermore, an algorithm and two examples for this symmetric reduction are presented.

Symmetry in event structures

A notion of symmetry for event structures is defined, which are based on permutation groups. Given an event structure and a permutation group over it, we introduce the quotient model of the event structure and show that the quotient model is trace, bisimulation and pomset equivalent to the original event structure.

The preservation of interleaving equivalences

In recent years, though many attempts have been made to solve whether equivalences are preserved under action refinement, this problem still needs to be further investigated. The usual approach to the preservation problem is: given some well-established equivalence notion which is not preserved under refinement, is there a way of adding some restricted conditions under consideration such that preservation of this equivalence in the restricted setting is obtained? Generally, one investigates how to restrict the concept of action refinement such that these equivalences are preserved under the restricted refinement. In this paper, in another way, we investigate how to find the class of suitable systems satisfying that the established equivalences on them are preserved under no restricted refinement. Interleaving trace equivalence and interleaving bisimulation equivalence which are not preserved under refinement are showed that they are preserved under refinement in the systems in which there are not causal independence relations or all the transitions are bundle action transitions.