Report Series 1999 ------------------ All reports are in PDF and postscript format compressed using gzip. Missing reports will be added soon or contact authors directly. Evaluating the CREWS-L'Ecritoire Requirements Elicitation Process (CREWS-99-19.ps) (PDF) Mustapha Tawbi, Fernando Velez, Carine Souveyet, Camille Ben Achour Submitted to ICRE 2000, Fourth IEEE International Conference on Requirements Engineering, Schaumburg, Illinois, USA, June 2000. Abstact The CREWS 21.903 long term research ESPRIT project has proposed several strategies to support requirements elicitation through textual scenarios analysis. In the CREWS-L'Ecritoire approach, guidelines are proposed to systematise these strategies. However these guidelines have never been evaluated so far. To evaluate the effectiveness of the CREWS-L'Ecritoire requirements elicitation guidelines, an empirical study was undertaken : several subjects were asked to apply the CREWS requirements elicitation strategies with and without guidance. The results of this experiment indicate that : (i.) subjects apply the CREWS-L'Ecritoire guiding rules with different rates of efficiency, (ii.) in average, all the guiding rules improve the subjects' ability to elicit correct requirements, and (iii.) each of the guiding rule has a different rate of efficiency. The paper presents the protocol used to conduct the experiment, and details the evaluation of these results for each of the three CREWS scenario based requirements elicitation strategies. Report on the CREWS-C2 Evaluations (CREWS-99-18.ps) (PDF) Paris team Abstract This document is a report on the evaluation of the approach developed in CREWS-C2 workpackage, namely CREWS-L'Ecritoire. This evaluation was performed during the reporting period E1. Regionale Kooperationskompetenz: Probleme und Modellierungstechniken (in German) (CREWS-99-17.ps) (PDF) Matthias Jarke, Stefanie Kethers in Wirtschaftsinformatik, Heft 4, August 1999, 41. Jahrgang Abstract Small and medium-sized enterprises (SMEs) can balance globalization efforts by participating in regional cooperation networks. As SMEs often have no or little experience with cooperation, they need to develop and maintain cooperation knowledge. From experiences in the German AdCo project, we derive a network of dependencies between problems occurring in regional cooperations, their causes, and possible countermeasures. In addition, we describe a combination of interrelated modelling methods which aid in analyzing cooperation processes with respect to strategic dependencies, service quality, and implications for the individual workplaces. Improving Reviews of Conceptual Models by Extended Traceability to Captured System Usage (CREWS-99-16.ps) (PDF) P. Haumer, M. Jarke, K. Pohl, K. Weidenhaupt to appear in Interacting with Computers, 1999. (Extended and revised version of HICSS '99 paper) Abtract When specifying change for an existing system, the history and functionality of the system to be replaced has to be considered. This avoids neglecting important system functionality and repeating errors. The properties and the rationale behind the existing system can be elicited by analysing concrete system-usage scenarios. The results of the analysis of the existing system are then typically represented using conceptual models. To establish conceptual models of high quality reviewing the models is common practice. The problem faced with when reviewing conceptual models, is that the reviewer cannot assess and therefore understand the basis (concrete system usage) on which the conceptual models were built. In this paper, we present an approach to overcome this problem. We establish Extended Trace-ability, by recording concrete system-usage scenarios using rich media (e.g. video, speech, graphic) and interrelating the recorded observations with the conceptual models. We discuss the main improvements for review processes and illustrate the advantages with excerpts from a case study performed in a mechanical engineering company. Automatically Structuring Requirement Scenarios (CREWS-99-15.ps) (PDF) Andreas Becks, Jörg Köller an abridged version of this paper appears in: Proceedings of the 14th IEEE International Conference on Automated Software Engineering, October 12-15, Cocoa Beach, Florida, USA, 1999. Abstract Scenarios are valuable for supporting communication among system developers in the initial phases of requirements engineering. But the problem of how to fruitfully deal with large informal or semi-formal scenario collections consisting of weakly structured texts is still a key research issue. In this paper we report on the application of a novel approach for automatically structuring textual document collections to scenario management. We discuss how structuring scenarios can help to support the analysis and maintenance of scenario collections. To evaluate this approach we present a case study within the CAPE-OPEN project which is concerned with a collaborative effort of standardizing simulator software for chemical engineering. Designing Standards for Open Simulation Environments in the Chemical Industries: A Computer-Supported Use-Case Approach (CREWS-99-14.ps) (PDF) M. Jarke, A. Becks, J. Köller, C. Tresp, B. Braunschweig in The Ninth Annual International Symposium of the International Council on Systems Engineering, INCOSE '99, June 6 - 10, 1999 Brighton, England. Abstract Under the double pressures of global competition and increasing environmental awareness, the importance of high-performance simulation tools in the process industries (food, chemicals, oil, ...) is rapidly growing. However, traditional simula-tion environments are closed monolithic systems which are extensible only by a small group of market-leading vendors. The resulting bottlenecks in interoperability, reuse and innovationled to the CAPE-OPEN project, in which the chemical and oil industries are defining standards for a component-based approach to process simulation, in order to open up the market to smaller vendors and to facilitate rapid industrial uptake of academic research prototypes. For general systems engineering, the CAPE-OPEN standardising process has at least two interesting features: (a) it has experimented on a large scale with a distributed use case approach, following a variant of the UML (Unified Modelling Language) approach for modelling, but also linking down to programming stan-dards based on CORBA (Common Object Request Broker Architecture) and COM (Common Object Model); (b) the management of this world-wide distributed effort has been facilitated by the use of an Internet-based workspace co-operation environment, augmented by advanced structuring and analysis methods from software engineering and computational intelligence. Towards Reference Models for Requirements Traceability. (CREWS-99-13.ps) (PDF) Bala Ramesh and Matthias Jarke Abstract Requirements traceability is intended to ensure continued alignment between stakeholder requirements and system evolution. To be useful, traces must be organized according to some modeling framework. Indeed, several such frameworks have been proposed, mostly based on theoretical considerations or analysis of other literature. This paper, in contrast, follows an empirical approach. Focus groups and interviews conducted in 26 major software development organizations demonstrate a wide range of traceability practices with distinct low-end and high-end users of traceability. From these observations, reference models comprising the most important kinds of traceability links for various development tasks have been synthesized. The resulting models have been validated in case studies and are incorporated in a number of commercial traceability tools. The discussion of the link types and their usage in practice has implications for the design of next-generation traceability methods and tools. Reusing Scenario Based Approaches in Requirement Engineering Methods: CREWS Method Base. (CREWS-99-12.ps) (PDF) J. Ralyté. To appear in Proceedings of the First International Workshop on the Requirements Engineering Process - Innovative Techniques, Models, Tools to support the RE Process, Florence, Italy, September 1999. Abstract not yet available. From Conceptual Modelling to Requirements Engineering. (CREWS-99-11.ps) (PDF) C. Rolland, N. Prakash. Submitted to Annals of Software Engineering, Special Volume on Comparative Studies of Engineering Approaches for Software Engineering Abstract Conceptual modelling is situated in the broader view of information systems requirements engineering. Requirements Engineering (RE) explores the objectives of different stakeholders and the activities carried out by them to meet these objectives in order to derive purposeful system requirements and therefore lead to better quality systems i.e. systems that meet the requirements of their users. Thus RE product models use concepts for modelling these instead of concepts like data, process, events etc. used in conceptual models. Since the former are more stable than the latter, requirements engineering manages change better. The paper gives the rationale for extending traditional conceptual models and introduce some RE product models. Furthermore, in contrast to conceptual modelling, requirements engineering lays great stress on the engineering process employed. The paper introduces some RE process models and considers their effect on tool support. Method Enhancement by Scenario Based Techniques. (CREWS-99-10.ps) (PDF) J. Ralyte, C. Rolland, V. Plihon. In Proceedings of CAISE 99, 11th Conference on Advanced Information Systems Engineering Heidelberg, Germany June 14-18, 1999. Abstract Scenarios have proven useful to elicit, validate and document requirements but cannot be used in isolation. Our concern in this paper is to integrate scenario-based techniques in existing methods. We propose a set of operators to support such an integration. This set is classified in two sub-sets: the one dealing with the integration of the product models of the two initial methods and the one concerned with the integration of their process models. The operators are used to integrate the CREWS-L'Ecritoire approach with the OOSE method. This leads to enhance the use case model construction of the OOSE method with on one hand, the linguistic techniques for scenario authoring and formalisation and on the other hand, the discovery strategies to elicit requirements by scenario analysis of the CREWS-L'Ecritoire approach. A Multi-Model View of Process Modelling. (CREWS-99-09.ps) (PDF) C. Rolland, N. Prakash. A. Benjamen. Submitted to Requirements Engineering Journal, 1999 Abstract Situatedness of development processes is a key issue in both the software engineering and the method engineering communities, as there is a strong felt need for process prescriptions to be adapted to the situation at hand. The assumption of the process modelling approach presented in this paper is that process prescriptions shall be selected according to the actual situation at hand i.e. dynamically in the course of the process. The paper focuses on a multi-model view of process modelling which supports this dynamicity. The approach builds on the notion of a labelled graph of intentions and strategies called a map as well as its associated guidelines. The map is a navigational structure which supports the dynamic selection of the intention to be achieved next and the appropriate strategy to achieve it whereas guidelines help in the operationalization of the selected intention. The paper presents the map and guidelines and exemplifies the approach with the CREWS-L'Ecritoire method for requirements engineering. Guiding the Process of Requirements Elicitation Through Scenario Analysis: Results of an Empirical Study (CREWS-99-08.ps) (PDF) C. Ben Achour, M. Tawbi, F. Velez To appear in Proceedings of the First International Workshop on the Requirements Engineering Process - Innovative Techniques, Models, Tools to support the RE Process, Florence, Italy, September 1999. Abstract not available. Bridging the Gap between Users and Requirements Engineering: the Scenario-Based Approach (CREWS-99-07.ps) (PDF) C. Ben Achour, C. Souveyet, M. Tawbi Submitted to Computer Systems Journal Abstract Scenarios have been advocated as a means of improving Requirements Engineering. The assumption is that scenarios allow users to better express their requirements (or more generally their knowledge of the constructed system) because they use their own vocabulary. In Europe, a few scenario-based methods and tools have already been developed in research; besides, scenarios are widely used in industry. In this context, the long Term Research 21.903 ESPRIT project CREWS has undertaken research on Cooperative Requirements Engineering With Scenarios. This work includes: i. surveys on scenario-based Requirements Engineering approaches and on the use of scenarios in European industry together with ii. the development of four interrelated methods for the acquisition and validation of requirements based on scenarios. This paper reports the CREWS objectives and achievements, and further details the CREWS-L'Ecritoire approach, which purpose is to guide the elicitation of requirements by exploiting textual scenarios. Then, pointers to the CREWS surveys, to the four interrelated CREWS approaches, and to on-going works undertaken by CREWS are given. Interrelating Goal Models and Multimedia Scenes: An Empirical Investigation. (CREWS-99-06.ps) (PDF) Peter Haumer, Jürgen Rack, Klaus Pohl in Fifth International Workshop on Requirements Engineering: Foundation for Software Quality (REFSQ '99), Heidelberg, Germany, June 14-15, 1999. Abstract Conceptual goal models are used to express intentional aspects of the system under de-velopment. Among others, goal models facilitate stakeholder discussions and agreement about main system aspects during early requirements engineering phases. As experiences from participatory design indicates, the use of multimedia representations (especially videos) leads to better stakeholder involvement and, as a consequence, the produced con-ceptual (goal) models and specifications respectively are of higher quality. In this paper, we report on our empirical investigation which shows that the use of asso-ciations between goals and video parts documenting goal achievements and goal failures improve the performance of typical requirements engineering tasks. More precisely, they lead to more correct and complete results. Document Maps: Semantic Structuring of Technical Document Collections (CREWS-99-05.ps) (PDF) Andreas Becks, Stefan Sklorz, Matthias Jarke Abstract Corporate knowledge management in science and engineering-intensive organizations involves tasks such as standard generation and evaluation, comparison of related cases and experience reuse in their treatment, and the ability to rapidly retrieve all relevant documents around a certain topic or project even if this project has extended over years or decades. No single information retrieval technique is likely to adequately deal with such tasks independent of the specific situation. In this paper, we therefore present a modular approach that allows a variety of techniques from clustering, exploitation of semantic structure knowledge, and visualization to be used in the handling of technical document collections for knowledge management purposes. Usable implementations exist for large parts of the approach. Two real-world usage experiences with projects in the chemical engineering and medical domains provide initial evidence for the value of the approach. Adapting Traceability Environments to Project-Specific Needs (CREWS-99-04.ps) (PDF) Ralf Dömges, Klaus Pohl Appeared in Communications of the ACM, Vol. 41, No. 12, December 1998. Abtract Traceability is a prerequisite for developing high quality (software) systems. Capturing and maintaining all available trace data is too labor intensive and thus by far too expensive. To reduce the efforts and the costs, the trace data and the trace strategies defining how to capture and use the trace data have to be adapted to project-specific needs. Such an adaptation is impossible without suitable tool support. To empower the adaptation of trace capture and trace usage according to project-specific needs we argue that trace environments should support the adaptation of trace strategies and trace data on a modeling level; guide the stakeholders in recording and using the trace data according to explicit process definitions; empower organizational learning based on the experiences made. We characterize the support offered by commercial trace environments, discuss their shortcomings and sketch future directions trace environments should strive for. Repository support for multi-perspective requirements engineering. (CREWS-99-03.ps) (PDF) Hans W. Nissen, Matthias Jarke Appeared in Lyytinen/Welke (eds.): Special Issue on Meta Modeling and Method Engineering, Information Systems vol. 24, no. 2, 1999. Abstract Relationships among different modeling perspectives have been systematically investigated focusing either on given notations (e.g. OMT) or on domain reference models (e.g. SAP). In contrast, many successful informal methods for business analysis and requirements engineering (e.g. JAD) emphasize team negotiation, goal orientation and exibility of modeling notations. This paper addresses the question how much formal and computerized support can be provided in such settings without destroying their creative tenor. Our solution comprises four components: (1) A modular conceptual modeling formalism organizes individual perspectives and their interrelationships. (2) Perspective schemata are linked to a conceptual meta meta model of shared domain terms, thus giving the architecture a semantic meaning and enabling adaptability and extensibility of the network of perspectives. (3) Inconsistency management across perspectives is handled in a goal-oriented man- ner, by de ning the analysis goals as meta rules which are automatically adapted to perspective schemata. (4) Continuous incremental maintenance of inconsistency information is provided by exploiting recent view maintenance techniques from de- ductive databases. The approach has been fully implemented as an extension to the ConceptBase meta database management system and is currently experimentally applied in the context of business analysis and data warehouse design. CREWS: Towards Systematic Usage of Scenarios, Use Cases and Scenes (CREWS-99-02.ps) (PDF) Matthias Jarke Appeared in WI (Wirtschaftsinformatik) 99, Saarbrücken, 3.-5. März 1999, Springer Aktuell Abstract In the wake of object-oriented software engineering, use cases have gained enormous popularity as tools for bridging the gap between electronic business management and information systems engineering. A wide variety of practices has emerged but their relationships to each other, and with respect to the traditional change management process, are poorly understood. The ESPRIT Long Term Research Project CREWS (Cooperative Requirements Engineering With Scenarios) has conducted surveys of the research literature and of the industry practice in scenario-based requirements engineering as a basis to develop a framework of approaches and research issues in the field. In two demonstrator prototypes, one based on textual scenario representations, the other on multimedia scenes, solutions to some of the most critical open problems from these surveys are being explored. The project results, besides being integrated in leading commercial software engineering environments, feed into a component-oriented method server on the Internet. Scenario Management: An Interdisciplinary Approach (CREWS-99-01.ps) (PDF) Matthias Jarke, X. Tung Bui, John M. Carroll Appeared in Requirements Engineering Journal, 1999 Abstract Scenario management (SM) means different things to different people, even though everyone seems to admit its current importance and its further potential. In this paper, we seek to provide an interdisciplinary framework for SM from three major disciplines that use scenarios - strategic management, human-computer interaction, and software and systems engineering - to deal with description of current and future realities. In particular, we attempt to answer to the following questions: How are scenarios developed and used in each of the three disciplines? Why are they becoming important? What are current research contributions in scenario management? What are the research and practical issues related to the creation and use of scenarios, in particular in the area of requirements engineering? Based on brainstorming techniques, this paper proposes an interdisciplinary definition of scenarios, frameworks for scenario development, use and evaluation, and directions for future research. Send questions and comments to crewsrep@informatik.rwth-aachen.de