Verification of functional and non-functional requirements of web service composition

Abstract. Web services have emerged as an important technology nowadays. There are two kinds of requirements that are crucial to web service composition, which are functional and non-functional requirements. Functional requirements focus on functionality of the composed service, e.g., given a booking service, an example of functional requirements is that a flight ticket with price higher than $2000 will never be purchased. Non-functional requirements are concerned with the quality of service (QoS), e.g., an example of the booking service’s non-functional requirements is that the service will respond to the user within 5 sec-onds. Non-functional requirements are important to web service composition, and are often an important clause in service-level agreements (SLAs). Even though the functional requirements are satisfied, a slow or unreliable service may still not be adopted. In our paper, we propose an automated approach to verify combined functional and non-functional requirements directly based on the semantics of web service composition. Our approach has been implemented and evaluated on the real-world case studies, which demonstrate the effectiveness of our method.

UTP, Circus, and Isabelle

We dedicate this paper with great respect and friendship to He Jifeng on the occasion of his 80th birthday. Our research group owes much to him. The authors have over 150 publications on unifying theories of programming (UTP), a research topic Jifeng created with Tony Hoare. Our objective is to recount the history of Circus (a combination of Z, CSP, Dijkstra’s guarded command language, and Morgan’s refinement calculus) and the development of Isabelle/UTP. Our paper is in two parts. (1) We first discuss the activities needed to model systems: we need to formalise data models and their behaviours. We survey our work on these two aspects in the context of Circus. (2) Secondly, we describe our practical implementation of UTP in Isabelle/HOL. Mechanising UTP theories is the basis of novel verification tools. We also discuss ongoing and future work related to (1) and (2). Many colleagues have contributed to these works, and we acknowledge their support

Contracts for Systems Design: Methodology and Application cases

Recently, contract based design has been proposed as an ”orthogonal” approach that can beapplied to all methodologies proposed so far to cope with the complexity of system design. Contract baseddesign provides a rigorous scaffolding for verification, analysis and abstraction/refinement. Companionreport RR-8759 proposes a unified treatment of the topic that can help in putting contract-based design in perspective.This paper complements RR-8759 by further discussing methodological aspects of system design withcontracts in perspective and presenting two application cases.The first application case illustrates the use of contracts in requirement engineering, an area of system designwhere formal methods were scarcely considered, yet are stringently needed. We focus in particular to thecritical design step by which sub-contracts are generated for suppliers from a set of different viewpoints(specified as contracts) on the global system. We also discuss important issues regarding certification inrequirement engineering, such as consistency, compatibility, and completeness of requirements.The second example is developed in the context of the Autosar methodology now widely advocated inthe automotive sector. We propose a contract framework to support schedulability analysis, a key step inAutosar methodology. Our aim differs from the many proposals for compositional schedulability analysisin that we aim at defining sub-contracts for suppliers, not just performing the analysis by parts—we knowfrom companion paper RR-8759 that sub-contracting to suppliers differs from a compositional analysis entirelyperformed by the OEM. We observe that the methodology advocated by Autosar is in contradiction withcontract based design in that some recommended design steps cannot be refinements. We show how tocircumvent this difficulty by precisely bounding the risk at system integration phase. Another feature ofthis application case is the combination of manual reasoning for local properties and use of the formalcontract algebra to lift a collection of local checks to a system wide analysis

Mathematics in Software Reliability and Quality Assurance

This monograph concerns the mathematical aspects of software reliability and quality assurance and consists of 11 technical papers in this emerging area. Included are the latest research results related to formal methods and design, automatic software testing, software verification and validation, coalgebra theory, automata theory, hybrid system and software reliability modeling and assessment

Event-B モデルの詳細化構造の計画とリファクタリングの支援手法

学位の種別: 課程博士審査委員会委員 : （主査）東京大学准教授 蓮尾 一郎, 東京大学教授 萩谷 昌己, 東京大学教授 小林 直樹, 東京大学教授 高野 明彦, 東京大学教授 千葉 滋University of Tokyo(東京大学

Factors Influencing Customer Satisfaction towards E-shopping in Malaysia

Online shopping or e-shopping has changed the world of business and quite a few people have decided to work with these features. What their primary concerns precisely and the responses from the globalisation are the competency of incorporation while doing their businesses. E-shopping has also increased substantially in Malaysia in recent years. The rapid increase in the e-commerce industry in Malaysia has created the demand to emphasize on how to increase customer satisfaction while operating in the e-retailing environment. It is very important that customers are satisfied with the website, or else, they would not return. Therefore, a crucial fact to look into is that companies must ensure that their customers are satisfied with their purchases that are really essential from the ecommerce’s point of view. With is in mind, this study aimed at investigating customer satisfaction towards e-shopping in Malaysia. A total of 400 questionnaires were distributed among students randomly selected from various public and private universities located within Klang valley area. Total 369 questionnaires were returned, out of which 341 questionnaires were found usable for further analysis. Finally, SEM was employed to test the hypotheses. This study found that customer satisfaction towards e-shopping in Malaysia is to a great extent influenced by ease of use, trust, design of the website, online security and e-service quality. Finally, recommendations and future study direction is provided. Keywords: E-shopping, Customer satisfaction, Trust, Online security, E-service quality, Malaysia