BibSonomyburst/user/neilernst/modelBibSonomy RSS feed for /user/neilernst/model2012-02-16T11:50:59+01:00http://www.bibsonomy.org/bibtex/20d33f6e4d9f3ff45b4b5f783269f9522/neilernstneilernst2009-07-22T03:31:11+02:00inconsistent model reasoning viewpoints <span class="authorEditorList"><a href="/author/Easterbrook">S. Easterbrook</a>, and <a href="/author/Chechik">M. Chechik</a> </span><em>International Conference on Software Engineering, </em><em>page 411-420. </em><em>Toronto, </em><em>IEEE Computer Society, </em>(<em>September 2001</em>)Wed Jul 22 03:31:11 CEST 2009TorontoInternational Conference on Software EngineeringSeptember411-420A framework for multi-valued reasoning over inconsistent viewpoints2001inconsistent model reasoning viewpoints http://www.bibsonomy.org/bibtex/23f2c97c5e9dc39d4043eb80ce8b234ad/neilernstneilernst2009-07-21T20:48:45+02:00evaluation i-star model <span class="authorEditorList"><a href="/author/Horkoff">Jennifer Horkoff</a> </span><em>University of Toronto, </em>(<em>2006</em>)Tue Jul 21 20:48:45 CEST 2009Using i* Models for Evaluation2006evaluation i-star model http://www.bibsonomy.org/bibtex/2e4d66a3a0bc5d72cecfcb3d666720a52/neilernstneilernst2009-05-11T20:55:29+02:00evolution model software <span class="authorEditorList"><a href="/author/van Deursen">Arie van Deursen</a>, <a href="/author/Visser">Eelco Visser</a>, and <a href="/author/Warmer">Jos Warmer</a> </span><em>CSMR Workshop on Model-Driven Software Evolution MoDSE 2007, </em><em>page 41--49. </em><em>Amsterdam, The Netherlands, </em>(<em>March 2007</em>)Mon May 11 20:55:29 CEST 2009Amsterdam, The NetherlandsCSMR Workshop on Model-Driven Software Evolution (MoDSE 2007)March41--49Model-Driven Software Evolution: A Research Agenda2007evolution model software http://www.bibsonomy.org/bibtex/2e53dd86c344da4ef73844bf46e64a1aa/neilernstneilernst2009-05-07T19:51:22+02:00model query <span class="authorEditorList"><a href="/author/Salay">Rick Salay</a>, and <a href="/author/Mylopoulos">John Mylopoulos</a> </span><em>International Conference on Advanced Information Systems, </em><em>Amsterdam, </em>(<em>June 2009</em>)<em>in press . </em>Thu May 07 19:51:22 CEST 2009AmsterdamInternational Conference on Advanced Information SystemsJunein pressImproving Model Quality Using Diagram Coverage Criteria2009model query Every model has a purpose and the quality of a model ultimately measures its fitness relative to this purpose. In practice, models are created in a piecemeal fashion through the construction of many diagrams that structure a model into parts that together offer a coherent presentation of the content of the model. Each diagram also has a purpose – its role in the presentation of the model - and this determines what part of the model the diagram is intended to present. In this paper, we investigate what is involved in formally characterizing this intended content of diagrams as coverage criteria and show how doing this helps to improve model quality and support automation in the modeling process. We illustrate the approach and its benefits with a case study from the telecommunications industry.http://www.bibsonomy.org/bibtex/2627bcab10e82caf8906de3c2eec085af/neilernstneilernst2009-02-04T18:13:55+01:00Model logic reasoning <span class="authorEditorList"><a href="/author/Easterbrook">S. M. Easterbrook</a>, and <a href="/author/Chechik">M. Chechik</a> </span><em>First International Workshop on Inconsistency in Data and Knowledge, at the International Joint Conference on Artificial Intelligence, IJCAI-01, </em><em>Seattle, USA, </em>(<em>August 2001</em>)Wed Feb 04 18:13:55 CET 2009Seattle, USAFirst International Workshop on Inconsistency in Data and Knowledge, at the International Joint Conference on Artificial Intelligence, (IJCAI-01)AugustAutomated Paraconsistent Reasoning via Model Checking2001Model logic reasoning Inconsistency is a pervasive problem in software engineering, where different aspects of a system are described in separate models. Resolving all the inconsistencies in a large set of models is often infeasible, in which case automated reasoning tools based on classical logic have limited application. In this paper we describe an automated tool for paraconsistent reasoning, using multi-valued logics. The reasoning engine is an adaptation of classical model checking, and works for any multi-valued logic whose truth values form a quasi-boolean lattice. We describe the design of the model checker, and show how it can be used to reason about models created by merging information from multiple conflicting sources.http://www.bibsonomy.org/bibtex/206dcf71f2a058f95f3cc133d1bee134c/neilernstneilernst2008-05-29T21:00:17+02:00evolution model requirements <span class="authorEditorList"><a href="/author/Wenzel">Sven Wenzel</a>, and <a href="/author/Kelter">Udo Kelter</a> </span><em>Intl Conf. on Software Engineering, </em><em>page 831-834. </em>(<em>May 2008</em>)Thu May 29 21:00:17 CEST 2008Intl Conf. on Software Engineeringconf/icse/2008May831-834Analyzing model evolution2008evolution model requirements Model-driven development leads to development processes in which a large number of different versions of models are produced. We present FAME, a tool environment which enables fine-grained analysis of the version history of a model. The tool is generic in the sense that it can work with various model types including UML and domain-specific languages.dblphttp://www.bibsonomy.org/bibtex/27fed6b9d5ee86952a5c9fc5a41f3cf27/neilernstneilernst2008-05-29T20:38:08+02:00diff model uml <span class="authorEditorList"><a href="/author/Wenzel">S. Wenzel</a>, <a href="/author/Hutter">H. Hutter</a>, and <a href="/author/Kelter">U. Kelter</a> </span><em>International Conference on Software Maintenance, </em><em>page 104-113. </em>(<em>October 2007</em>)Thu May 29 20:38:08 CEST 2008International Conference on Software MaintenanceOctober104-113Tracing Model Elements2007diff model uml In model-driven engineering developers work mainly or only with models, which exist in many versions. This paper presents an approach to trace single model elements or groups of elements within a version history of a model. It also offers analysis capabilities such as detection of logical coupling between model elements. The approach uses a differencing algorithm blown as SiDiff to identify similar elements in different versions of a model. SiDiff is highly configurable and thus our tracing approach can be adapted to all diagram types of the UML and to a large set of domain specific languages. The approach has been implemented as an Eclipse plug-in that visualizes all relevant information about the traces and it allows developers to interactively explore details. It has been evaluated by several groups of test persons; they considered most of the functions of the tool to be very usefulhttp://www.bibsonomy.org/bibtex/2fe254bec82e3dd5510e0a4aff89f2cb1/neilernstneilernst2008-04-28T17:42:32+02:00Database Information Model Object-Oriented Repository Versions <span class="authorEditorList"><a href="/author/Bernstein">Philip A. Bernstein</a>, <a href="/author/Bergstraesser">Thomas Bergstraesser</a>, <a href="/author/Carlson">Jason Carlson</a>, <a href="/author/Pal">Shankar Pal</a>, <a href="/author/Sanders">Paul Sanders</a>, and <a href="/author/Shutt">David Shutt</a> </span><em>Information Systems</em> <em>24(2):71--98</em> (<em>April 1999</em>)Mon Apr 28 17:42:32 CEST 2008Meta-Modelling and Methodology EngineeringInformation Systems#apr#271--98Microsoft repository version 2 and the open information model,241999Database Information Model Object-Oriented Repository Versions Microsoft Repository is an object-oriented meta-data management facility that ships in Microsoft Visual Studio and Microsoft SQL Server. It includes two main components: - - A repository engine that implements a set of object-oriented interfaces on top of a SQL database system. A developer can use these interfaces to define information models (i.e., schemas) and manipulate instances of the models.- - The Open Information Model, which is a set of information models that cover object modeling, database modeling, and component reuse. The repository system is designed to meet the persistent storage needs of software tools. Its main technical goals are: - - Compatibility with Microsoft's Component Object Model (COM) architecture- - Extensibility by customers and independent software vendors, so they can add behavior to objects stored by the repository engine and extend information models provided by Microsoft and others.- - Flexible and efficient versioning, configuration management, and checkout/checkin to support team-oriented activities. This paper describes the programming interface and implementation of the repository engine and the Open Information Model.http://www.bibsonomy.org/bibtex/2febce57c432f73f2dcae34f0d14c330c/neilernstneilernst2008-04-03T21:06:12+02:00engineering model system <span class="authorEditorList"><a href="/author/Boehm">Barry Boehm</a>, and <a href="/author/Lane">Jo Ann Lane</a> </span><em>Crosstalk: Journal of Defence Software Engineering</em> (<em>October 2007</em>)Thu Apr 03 21:06:12 CEST 2008Crosstalk: Journal of Defence Software EngineeringOctoberUsing the Incremental Commitment Model to Integrate System Acquisition, Systems Engineering, and Software Engineering2007engineering model system One of the top recommendations to emerge from the October 2006 Deputy Under Secretary of Defense (DUSD) Acquisition, Technology, and Logistics (ATL) Defense Software Strategy Summit was to find ways of better integrating software engineering into the systems engineering and acquisition process. Concurrently, the National Research Council (NRC) study was addressing the problem of better integrating human factors into the systems engineering and acquisition process. This article presents a model that emerged from these and related efforts that shows promise of improving integrations. This model, called the Incremental Commitment Model (ICM), organizes systems engineering and acquisition processes in ways that better accommodate the different strengths and difficulties of hardware, software, and human factors of engineering approaches. It also provides points at which they can synchronize and stabilize, and at which their risks of going forward can be better assessed and fitted into a risk-driven stakeholder resource commitment process.http://www.bibsonomy.org/bibtex/2be5a7547c8bb11fb674f3aaed74b03d7/neilernstneilernst2008-01-30T04:30:30+01:00conceptual consistency merging model <span class="authorEditorList"><a href="/author/Sabetzadeh">Mehrdad Sabetzadeh</a>, <a href="/author/Nejati">Shiva Nejati</a>, <a href="/author/Liaskos">Sotirios Liaskos</a>, <a href="/author/Easterbrook">Steve Easterbrook</a>, and <a href="/author/Chechik">Marsha Chechik</a> </span><em>International Conference on Requirements Engineering, </em><em>New Delhi, India, </em>(<em>October 2007</em>)Wed Jan 30 04:30:30 CET 2008New Delhi, IndiaInternational Conference on Requirements Engineering OctoberConsistency Checking of Conceptual Models via Model Merging2007conceptual consistency merging model http://www.bibsonomy.org/bibtex/20194bcfa92f21ac8ea1a6eae482d5cb2/neilernstneilernst2008-01-29T16:00:26+01:00Software evolution model <span class="authorEditorList"><a href="/author/Sneed">Harry Sneed</a> </span><em>Workshop on Model-Driven Software Evolution at CSMR, </em><em>Amsterdam, </em>(<em>March 2007</em>)Tue Jan 29 16:00:26 CET 2008AmsterdamWorkshop on Model-Driven Software Evolution at CSMRMarchThe Drawbacks of Model-Driven Software Evolution2007Software evolution model This short paper is an essay on the drawbacks of model driven software evolution which apply equally well to model driven software development. The idea of automatically generating code changes from a UML type model is equally enticing as that of automatically generating whole components from such a model. The drawback is that there is then nothing to test against, since there is only one description of the system, the model. This violates the principles of software verification and validation, according to which correctness can only be demonstrated by comparing two independent descriptions of the same solution. For this reason, the author proposes another interpretation of model driven evolution, one in which the requirements model serves as a basis for propagating changes to both the code and the test, along two independent paths. The UML type system design could then be generated from the code and not [vice] versahttp://www.bibsonomy.org/bibtex/254f52b25733dc0470387774affa58810/neilernstneilernst2008-01-16T02:46:44+01:00cognition framework model personal <span class="authorEditorList"><a href="/author/Aranda">Jorge Aranda</a>, <a href="/author/Ernst">Neil A. Ernst</a>, <a href="/author/Horkoff">Jennifer Horkoff</a>, and <a href="/author/Easterbrook">S. M. Easterbrook</a> </span><em>International Workshop on Modeling in Software Engineering at ICSE, </em><em>Minneapolis, USA, </em>(<em>May 2007</em>)Wed Jan 16 02:46:44 CET 2008Minneapolis, USAInternational Workshop on Modeling in Software Engineering at ICSEMayA Framework for Empirical Evaluation of Model Comprehensibility2007cognition framework model personal If designers of modelling languages want their creations to be used in real software projects, the communication qualities of their languages need to be evaluated, and their proposals must evolve as a result of these evaluations. A key quality of communication artifacts is their comprehensibility. We present a flexible framework to evaluate the comprehensibility of model representations that is grounded on the underlying theory of the language to be evaluated, and on theoretical frameworks in cognitive science.http://www.bibsonomy.org/bibtex/201f1ebd9c0df9c02f2851cf1ebcd27d5/neilernstneilernst2008-01-04T22:43:42+01:00Requirements change evolution model <span class="authorEditorList"><a href="/author/Lam">W. Lam</a>, and <a href="/author/Loomes">M. Loomes</a> </span><em>Euromicro Conference on Software Maintenance and Reengineering, </em><em>page 121-127. </em><em>Florence, Italy, </em><em>IEEE, </em>(<em>March 1998</em>)<em>Requirements evolve, not only during system development but also after a system has been installed. The aim of the work on the EVE EVolution Engineering pr<span class="info">...<div>Requirements evolve, not only during system development but also after a system has been installed. The aim of the work on the EVE EVolution Engineering project is to develop practi-cal methods for dealing with requirements evolution. This pa-per presents the early output from our work-the EVE frame-work for requirements evolution. The EVE framework is com-prised of two components: a meta-model and an associated process model. The EVE meta-model captures a set of model-ling concepts in requirements evolution, including change, impact, risk and viewpoint. The EVE process model provides technologists with a framework for handling the emergence of new or changing requirements during the lifetime of a system. The paper illustrates the EVE framework on a simple example, and highlights the importance of social and environmental re-sponsibility in requirements evolution.</div></span> . </em>Fri Jan 04 22:43:42 CET 2008Florence, ItalyEuromicro Conference on Software Maintenance and ReengineeringMarchRequirements evolve, not only during system development but also after a system has been installed. The aim of the work on the EVE (EVolution Engineering) project is to develop practi-cal methods for dealing with requirements evolution. This pa-per presents the early output from our work-the EVE frame-work for requirements evolution. The EVE framework is com-prised of two components: a meta-model and an associated process model. The EVE meta-model captures a set of model-ling concepts in requirements evolution, including change, impact, risk and viewpoint. The EVE process model provides technologists with a framework for handling the emergence of new or changing requirements during the lifetime of a system. The paper illustrates the EVE framework on a simple example, and highlights the importance of social and environmental re-sponsibility in requirements evolution.121-127Requirements Evolution in the Midst of Environmental Change: A Managed Approach1998Requirements change evolution model Requirements evolve, not only during system development but also after a system has been installed. The aim of the work on the EVE (EVolution Engineering) project is to develop practi-cal methods for dealing with requirements evolution. This pa-per presents the early output from our work-the EVE frame-work for requirements evolution. The EVE framework is com-prised of two components: a meta-model and an associated process model. The EVE meta-model captures a set of model-ling concepts in requirements evolution, including change, impact, risk and viewpoint. The EVE process model provides technologists with a framework for handling the emergence of new or changing requirements during the lifetime of a system. The paper illustrates the EVE framework on a simple example, and highlights the importance of social and environmental re-sponsibility in requirements evolution.zoterohttp://www.bibsonomy.org/bibtex/27518dbc82f02617833f04532a4ffce39/neilernstneilernst2008-01-03T21:51:56+01:00merging model <span class="authorEditorList"><a href="/author/Brunet">G. Brunet</a>, <a href="/author/Chechik">M. Chechik</a>, <a href="/author/Easterbrook">S. M. Easterbrook</a>, <a href="/author/Nejati">S. Nejati</a>, <a href="/author/Niu">N. Niu</a>, and <a href="/author/Sabetzadeh">M. Sabetzadeh</a> </span><em>Workshop on Global Integrated Model Management GaMMa&#039;06 at the 28th International Conference on Software Engineering, </em><em>Shanghai, China, </em>(<em>May 2006</em>)Thu Jan 03 21:51:56 CET 2008Shanghai, ChinaWorkshop on Global Integrated Model Management (GaMMa'06) at the 28th International Conference on Software EngineeringMayA Manifesto for Model Merging2006merging model If a modeling task is distributed, it will frequently be neces- sary to merge models developed by dierent team members. Existing approaches to model merging make assumptions about the types of model to be merged, and the nature of the relationship between them. This makes it hard to compare approaches. In this paper, we present a manifesto for re- search on model merging. We propose a framework for com- paring dierent approaches to merging, by treating merge as an algebraic operator over models and model relationships. We specify the algebraic properties of an idealized merge operator, as well as related operators such as match, di, split, and slice. We then show how our framework can be used to compare existing approaches by applying it to two of our own research projects on model merging. We show how this analysis permits a detailed comparison of approaches, reveals the key features of each, and identies weaknesses that require further research. Most importantly, the frame- work emphasizes the need to make explicit all assumptions about the relationships between models, and indeed to treat model relationships as rst class objects.Contains Steve's operators for model managementhttp://www.bibsonomy.org/bibtex/29f9b7dd0295eb686415b2333f43bb3f1/neilernstneilernst2007-12-31T17:44:01+01:00model requirements traceability <span class="authorEditorList"><a href="/author/Almeida">João Almeida</a>, <a href="/author/Iacob">Maria-Eugenia Iacob</a>, and <a href="/author/van Eck">Pascal van Eck</a> </span><em>Information Systems Frontiers</em> <em>9(4):327--342</em> (<em>September 2007</em>)Mon Dec 31 17:44:01 CET 2007Information Systems Frontiers#sep#4327--342Requirements traceability in model-driven development: Applying model and transformation conformance92007model requirements traceability The variety of design artifacts (models) produced in a model-driven design process results in an intricate relationship between requirements and the various models. This paper proposes a methodological framework that simplifies management of this relationship,which helps in assessing the quality of models, realizations and transformation specifications. Our framework is a basis for understanding requirements traceability in model-driven development, as well as for the design of tools that support requirements traceability in model-driven development processes. We propose a notion of conformance between application models which reduces the effort needed for assessment activities. We discuss how this notion of conformance can be integrated with model transformations.http://www.bibsonomy.org/bibtex/260f04df74fd1fc45813dc22dbf90a603/neilernstneilernst2007-11-30T22:40:27+01:00evolution goal model requirements reverse <span class="authorEditorList"><a href="/author/Yu">Yijun Yu</a>, <a href="/author/Wang">Yiqiao Wang</a>, <a href="/author/Mylopoulos">J. Mylopoulos</a>, <a href="/author/Liaskos">S. Liaskos</a>, and <a href="/author/Lapouchnian">A. Lapouchnian</a> </span><em>International Conference on Requirements Engineering, </em><em>page 363--372. </em>(<em>2005</em>)Fri Nov 30 22:40:27 CET 2007International Conference on Requirements Engineering363--372Reverse engineering goal models from legacy code2005evolution goal model requirements reverse A reverse engineering process aims at reconstructing high-level abstractions from source code. This paper presents a novel reverse engineering methodology for recovering stakeholder goal models from both structured and unstructured legacy code. The methodology consists of the following major steps: 1) Refactoring source code by extracting methods based on comments; 2) Converting the refactored code into an abstract structured program through statechart refactoring and hammock graph construction; 3) Extracting a goal model from the structured program's abstract syntax tree; 4) Identifying nonfunctional requirements and derive soft goals based on the traceability between the code and the goal model. To illustrate this requirements recovery process, we refactor stakeholder goal models from two legacy software code bases: an unstructured Web-based email in PHP (SquirrelMail) and a structured email client system in Java (Columba).sdasdahttp://www.bibsonomy.org/bibtex/263643e3c220cc708d4e4711231a66c9a/neilernstneilernst2007-10-19T18:55:16+02:00merge model statecharts <span class="authorEditorList"><a href="/author/Nejati">Shiva Nejati</a>, <a href="/author/Sabetzadeh">Mehrdad Sabetzadeh</a>, <a href="/author/Chechik">Marsha Chechik</a>, <a href="/author/Easterbrook">Steven Easterbrook</a>, and <a href="/author/Zave">Pamela Zave</a> </span>(<em>May 2007</em>)<em>Model Management addresses the problem of managing an evolving collection of models, by capturing the relationships between models and providing well-defin<span class="info">...<div>Model Management addresses the problem of managing an evolving collection of models, by capturing the relationships between models and providing well-defined operators to manipulate them. In this paper, we describe two such operators for manipulating hierarchical Statecharts: Match, for finding correspondences between models, and Merge, for combining models with respect to known correspondences between them. Our Match operator is heuristic, making use of both static and behavioural properties of the models to improve the accuracy of matching. Our Merge operator preserves the hierarchical structure of the input models, and handles differences in behaviour through parameterization. In this way, we automatically construct merges that preserve the semantics of Statecharts models. We illustrate and evaluate our work by applying our operators to AT\&amp;T telecommunication features.</div></span> . </em>Fri Oct 19 18:55:16 CEST 2007MayModel Management addresses the problem of managing an evolving collection of models, by capturing the relationships between models and providing well-defined operators to manipulate them. In this paper, we describe two such operators for manipulating hierarchical Statecharts: Match, for finding correspondences between models, and Merge, for combining models with respect to known correspondences between them. Our Match operator is heuristic, making use of both static and behavioural properties of the models to improve the accuracy of matching. Our Merge operator preserves the hierarchical structure of the input models, and handles differences in behaviour through parameterization. In this way, we automatically construct merges that preserve the semantics of Statecharts models. We illustrate and evaluate our work by applying our operators to AT\&T telecommunication features.Matching and Merging of Statecharts Specificationstext2007merge model statecharts Model Management addresses the problem of managing an evolving collection of models, by capturing the relationships between models and providing well-defined operators to manipulate them. In this paper, we describe two such operators for manipulating hierarchical Statecharts: Match, for finding correspondences between models, and Merge, for combining models with respect to known correspondences between them. Our Match operator is heuristic, making use of both static and behavioural properties of the models to improve the accuracy of matching. Our Merge operator preserves the hierarchical structure of the input models, and handles differences in behaviour through parameterization. In this way, we automatically construct merges that preserve the semantics of Statecharts models. We illustrate and evaluate our work by applying our operators to AT\&T telecommunication features.zoterohttp://www.bibsonomy.org/bibtex/26e39f1dd1112b852b356b6a43ca57103/neilernstneilernst2007-10-19T18:55:16+02:00computing, computing,nolan&#039;s evolution model of stages <span class="authorEditorList"><a href="/author/King">John Leslie King</a>, and <a href="/author/Kraemer">Kenneth L. Kraemer</a> </span> (<em>May 1984</em>)Fri Oct 19 18:55:16 CEST 2007May466-475 Evolution and organizational information systems: an assessment of Nolan's stage model 27 1984computing, computing,nolan's evolution model of stages Richard Nolan's stage model is the best known and most widely cited model of computing evolution in organizations. The model's development over a decade demonstrates its own evolution from a simple theory, based on the factoring of change states indicated by changes in computing budgets, to an elaborate account of the characteristics of six stages of computing growth. An analysis of the model's logical and empirical structure reveals a number of problems in its formulation that help to account for the fact that its principal tenets have not been independently validated. The model is shown to be an ?evolutionistic? theory within the theories of evolution in the social sciences, focusing on assumed directions of growth and an implied end state toward which growth proceeds, and suffering from problems inherent in such theories. Further research based on an ?evolutionary? view of computing growth is suggested as a means of improving theories of computing in organizations.zoterohttp://www.bibsonomy.org/bibtex/2b29a6a271fc1d4f991acb0092c770350/neilernstneilernst2007-06-09T18:08:11+02:00goal kaos model requirements <span class="authorEditorList"><a href="/author/Dardenne">Anne Dardenne</a>, <a href="/author/van Lamsweerde">Axel van Lamsweerde</a>, and <a href="/author/Fickas">Stephen Fickas</a> </span><em>Science of Computer Programming</em> <em>20(1-2):3--50</em> (<em>April 1993</em>)Sat Jun 09 18:08:11 CEST 2007Science of Computer ProgrammingApril1-23--50Goal-directed requirements acquisition201993goal kaos model requirements Requirements analysis includes a preliminary acquisition step where a global model for the specification of the system and its environment is elaborated. This model, called requirements model, involves concepts that are currently not supported by existing formal specification languages, such as goals to be achieved, agents to be assigned, alternatives to be negotiated, etc. The paper presents an approach to requirements acquisition which is driven by such higher-level concepts. Requirements models are acquired as instances of a conceptual meta-model. The latter can be represented as a graph where each node captures an abstraction such as, e.g., goal, action, agent, entity, or event, and where the edges capture semantic links between such abstractions. Well-formedness properties on nodes and links constrain their instances--that is, elements of requirements models. Requirements acquisition processes then correspond to particular ways of traversing the meta-model graph to acquire appropriate instances of the various nodes and links according to such constraints. Acquisition processes are governed by strategies telling which way to follow systematically in that graph; at each node specific tactics can be used to acquire the corresponding instances. The paper describes a significant portion of the meta-model related to system goals, and one particular acquisition strategy where the meta-model is traversed backwards from such goals. The meta-model and the strategy are illustrated by excerpts of a university library system.http://www.bibsonomy.org/bibtex/2179d71111ee7829c6d2be29f5022ee72/neilernstneilernst2007-03-02T22:56:50+01:00i-star model requirements software 1406 <span class="authorEditorList"><a href="/author/Yu">Eric S. Yu</a> </span><em>International Symposium on Requirements Engineering, </em><em>page 226--235. </em><em>Annapolis, Maryland, </em>(<em>1997</em>)Fri Mar 02 22:56:50 CET 2007Annapolis, MarylandInternational Symposium on Requirements Engineering226--235Towards modelling and reasoning support for early-phase requirements engineering1997i-star model requirements software 1406 Requirements are usually understood as stating what a system is supposed to do, as apposed to how it should do it. However, understanding the organizational context and rationales (the “Whys”) that lead up to systems requirements can be just as important for the ongoing success of the system. Requirements modelling techniques can be used to help deal with the knowledge and reasoning needed in this earlier phase of requirements engineering. However most existing requirements techniques are intended more for the later phase of requirements engineering, which focuses on completeness, consistency, and automated verification of requirements. In contrast, the early phase aims to model and analyze stakeholder interests and how they might be addressed, or compromised, by various system-and-environment alternatives. This paper argues, therefore, that a different kind of modelling and reasoning support is needed for the early phase. An outline of the i* framework is given as an example of a step in this direction. Meeting scheduling is used as a domain examplesdasda