Reconciliation of object interaction models

This paper presents Reconciliation+, a tool-supported method which identifies overlaps between models of different object interactions expressed as UML sequence and/or collaboration diagrams, checks whether the overlapping elements of these models satisfy specific consistency rules, and guides developers in handling these inconsistencies. The method also keeps track of the decisions made and the actions taken in the process of managing inconsistencies

Supporting the reconciliation of models of object behaviour

This paper presents Reconciliation+, a method which identifies overlaps between models of software systems behaviour expressed as UML object interaction diagrams (i.e., sequence and/or collaboration diagrams), checks whether the overlapping elements of these models satisfy specific consistency rules and, in cases where they violate these rules, guides software designers in handling the detected inconsistencies. The method detects overlaps between object interaction diagrams by using a probabilistic message matching algorithm that has been developed for this purpose. The guidance to software designers on when to check for inconsistencies and how to deal with them is delivered by enacting a built-in process model that specifies the consistency rules that can be checked against overlapping models and different ways of handling violations of these rules. Reconciliation+ is supported by a toolkit. It has also been evaluated in a case study. This case study has produced positive results which are discussed in the paper

Functional Modelling of Systems with Multiple Operation Modes: Case Study on an Active Spoiler System

YesThis article presents the application of the Enhanced Sequence Diagram (ESD) for the analysis of the functionality of a system with shape-changing aspects in the context of its multiple operational modes, considering an active rear spoiler as a case study. The article provides new insights on the ESD support for model-based capture and articulation of functional requirements across multiple operation modes of the same system, with appropriate detail on attributes and metrics, and the alignment of these attributes and metrics in line with the concept of time through scope lines. The article also provides a comprehensive argument and discussion, exemplified based on the case study, for the support that the ESD provides for early systems functional and architecture analysis, within the context of a broader model-based Failure Mode Analysis methodology

A framework for defining and analysing access policies in requirements models

Enforcing access policies derived from management control principles is a way by which organisations protect their information assets. The minimum privileges principle is an example of a management control principle, which specifies that users should only have access to resources they require to carry out their duties. Requirements models use actors to specify their access policies. Actors normally represent roles that users adopt, however a role can have different meanings, such as a position in an organisation or the assignment of a task, and can therefore be misleading. Current requirements modelling approaches do not provide a systematic way of defining roles for incorporation into access policies, and therefore we can not ensure that they satisfy management control principles. In this thesis we address the need to provide precise role definitions by developing a framework that facilitates the derivation of roles from the organisational context. The framework consists of a metamodel, which enables the organisational context to be represented and related to actors; a set of heuristics for deriving the organisational context; and a set of language constructs for formulating access policies, and verifying them using scenarios. We use the meta-model and language constructs that we developed to extend an existing requirements modelling language, the i* framework, and in particular a formal version of it, formal Tropos, to define and verify access policies definitions satisfying the minimum privileges principle. We also investigate the use of automated tool checking by translating the formal Tropos definitions into the specification language Alloy, which is supported by a tool that automatically checks assertions, to ensure consistency of the access policy definitions. We carry out a detailed case study taken from the literature to verify the extensions to the i* framework and the tool supported analysis. The framework presented in this thesis makes a novel contribution to the modelling of access policies as requirements, enabling us to define access policies using actors derived from the organisational context, that satisfy the minimum privileges principle

Una heurística de derivación de LEL a escenarios

El objetivo principal de este trabajo de tesis está centrado en derivar escenarios contribuyendo y enriqueciendo las estrategias existentes. Utilizaremos la información del LEL que aún no ha sido tenido en cuenta, con el propósito de generar escenarios más completos que describan mejor los requerimientos funcionales.Facultad de Informátic

Requirement validation with enactable descriptions of use cases.

The validation of stakeholder requirements for a software system is a pivotal activity for any nontrivial software development project. Often, differences in knowledge regarding development issues, and knowledge regarding the problem domain, impede the elaboration of requirements amongst developers and stakeholders. A description technique that provides a user perspective of the system behaviour is likely to enhance shared understanding between the developers and stakeholders. The Unified Modelling Language (UML) use case is such a notation. Use cases describe the behaviour of a system (using natural language) in terms of interactions between the external users and the system. Since the standardisation of the UML by the Object Management Group in 1997, much research has been devoted to use cases. Some researchers have focussed on the provision of writing guidelines for use case specifications whereas others have focussed on the application of formal techniques. This thesis investigates the adequacy of the use case description for the specification and validation of software behaviour. In particular, the thesis argues that whereas the user-system interaction scheme underpins the essence of the use case notation, the UML specification of the use case does not provide a mechanism by which use cases can describe dependencies amongst constituent interaction steps. Clarifying these issues is crucial for validating the adequacy of the specification against stakeholder expectations. This thesis proposes a state-based approach (the Educator approach) to use case specification where constituent events are augmented with pre and post states to express both intra-use case and inter-use case dependencies. Use case events are enacted to visualise implied behaviour, thereby enhancing shared understanding among users and developers. Moreover, enaction provides an early "feel" of the behaviour that would result from the implementation of the specification. The Educator approach and the enaction of descriptions are supported by a prototype environment, the EducatorTool, developed to demonstrate the efficacy and novelty of the approach. To validate the work presented in this thesis an industrial study, involving the specification of realtime control software, is reported. The study involves the analysis of use case specifications of the subsystems prior to the application of the proposed approach, and the analysis of the specification where the approach and tool support are applied. This way, it is possible to determine the efficacy of the Educator approach within an industrial setting

Vers une approche orientée aspect d'ingénierie des besoins dans les organisations multi-entreprises

It is often difficult for a single Information System (IS) to accomplish complex requirements. One solution is to combine many different ISs and make them collaborate to realize this task. Information systems composition is an active ongoing area of research in the field of information systems. The result of IS composition produces one type of a so called Cooperative Information System (CIS). Its development requires a particular attention to process all emerging problems, especially the crosscutting concerns that pose difficulties to understand, maintain and reuse such cooperative systems. Moreover, the aspect paradigm is presented as a promising avenue for reusability. Thus, we argue that it is interesting to propose an aspect approach to build a new system in order to accomplish complex tasks based on the reuse of system’s artefacts previously developed. According to our best of knowledge few works have tackled this question. In this thesis, we present an aspect-oriented approach called AspeCiS, applied from the requirements engineering phase until the design phase, in order to develop a CIS from existing ISs by using their artifacts such as requirements, architectures and design. Therefore, this approach is opposed to conventional development ones in which the construction of a new system starts from nothing and needs reinventing everything every time.Le système d’information coopératif (SIC) est un élément central dans le domaine de la coopération interentreprises. Son développement nécessite une attention particulière afin de prendre en considération tous les problèmes émergeants, surtout celui des préoccupations transversales qui posent des difficultés pour la compréhension, la maintenance, l’évolution, et la réutilisation des systèmes développés. Dans les approches usuelles de développement, la construction de ce genre de système part de zéro et nécessite de tout reconstruire à chaque fois. Nos travaux de recherche dans cette thèse examinent comment une approche orientée aspect appliquée de la phase de recueil des exigences à la phase de conception peut être proposée comme un outil permettant de développer des SICs à partir de systèmes d’information (SIs) préalablement existants produits à l’occasion de développements antérieurs. L’utilisation du paradigme Aspect dans cette approche tente de réutiliser des artéfacts des SIs existants afin de développer le futur SIC supportant la coopération interentreprises

Decision Maps for Distributed Scenario-Based Multi-Criteria Decision Support

This thesis presents the Decision Map approach to support decision-makers facing complex uncertain problems that defy standardised solutions. First, scenarios are generated in a distributed manner: the reasoning processes can be adapted to the problem at hand whilst respecting constraints in time and availability of experts. Second, by integrating scenarios and MCDA, this approach facilitates robust decision-making respecting multiple criteria in a transparent well-structured manner