The purpose of this paper is to build the foundation for software architecture. We first develop an intuition for software architecture by appealing to several well-established architectural disciplines. On the basis of this intuition, we present a model of software architec-ture that consists of three components: elements, form, and rationale. Elements are either processing, data, or connecting elements. Form is defined in terms of the properties of, and the relationships among, the elements-- that is, the constraints on the elements. The ratio-nale provides the underlying basis for the architecture in terms of the system constraints, which most often derive from the system:requirements. We discuss the compo-nents of the model in the context of both architectures and architectural styles and present an extended exam-ple to illustrate some important architecture and style considerations. We conclude by presenting some of the benefits of our approach to software architecture, sum-marizing our contributions, and relating our approach to other current work.

Continuant Occurrent ' rContinuant Occurrent Object Process Schema Script Juncture Participation Description History Structure Situation Reason Purpose Three-dimensional matrix of twelve of Sowa's categories (p. 75).

For many companies, the strategic as well as the organizational fit of their information systems is a pivotal factor for staying competitive. At the same time, there is an increasing demand for integrating business processes and informations systems with those of customers and suppliers. The resulting need for organizational changes and the introduction of corresponding information systems is a challenging task. The complexity of the task requires a separation of concerns. At the same time it causes language barriers between various stakeholders, especially between business people and information technology professionals. Enterprise models provide various abstractions that help with the design of corporate information systems which are in line with a company’s organization and its long term strategy. They also promise to provide a common conceptual foundation to foster the communication between people with different professional backgrounds. In this paper we introduce a model for enterprise modelling that is based on an extendable set of special purpose modeling languages, e.g. for describing corporate strategies, business processes, resources or information. The visual languages provide intuitive abstractions for various observers. The languages are defined in metamodels which in turn are specified through a common meta-metamodel. Similar to a specialized technical language, they provide concepts that help with structuring and analyzing a domain according to specific objectives. Since the languages are specified in a semi-formal way, the models allow for the generation of software prototypes. The languages share common concepts which allow for a tight integration of the various parts of an enterprise model. In addition to offering specialized modeling languages, the modeling method also includes examples, case studies and reference models- to promote the re-use of concepts and artefacts. The use of the method is illustrated by an example, where two different partial models are being integrated.

vi vii P...`".--d...#^TM"..."fddo/oo"# f...+...~..."do/oo...~fo/ood...fdee~#f..~ .'."o/oo^TMf...#--~."efdo/oo...^TMi^TMd..."..." Om succesvol te blijven moeten productiesystemen zich steeds vaker aanpassen aan nieuwe omstandigheden: nieuwe technologien, nieuwe producten, nieuwe organisatiestructuren, etc. Deze thesis ontwikkelt een referentiearchitectuur voor productiebesturing die veranderingen en herconfiguratie van het productiebesturingssysteem mogelijk maakt. Tegelijk moet de architectuur toch efficinte logistieke en technische plannings- en uitvoeringsalgoritmen toelaten voor het besturen van grote en heterogene productiesystemen. Er wordt inspiratie gezocht in het paradigma van holonische productiesystemen. Naar analogie met biologische en sociale systemen, hebben ze een hirarchische structuur bestaande uit autonome en samenwerkende entiteiten of holons.

Non-functional requirements, such as modifiability, performance, reusability, comprehensibility and security, are often crucial to a software system. As such, these non-functional requirements (or NFRs) should be addressed as early as possible in a software lifecycle and properly reflected in a software architecture before committing to a detailed design. The purpose of this paper is to discuss how the treatment of NFRs as goals (which may be synergistic or conflicting) serves to systematically guide selection among architectural design alternatives. During the architectural design process, goals are decomposed, design alternatives are analysed with respect to their tradeoffs, design decisions are made rationalised, and goal achievement is evaluated. This process can be supported by by a body of organised knowledge. This paper outlines an approach by which such knowledge can be organized. This approach is illustrated by a preliminary study of architectural design for a KWIC (Key Word i...

Alignment of application architecture to business architecture is a central problem in the design, acquisition and implementation of information systems in current large-scale information-processing organizations. Current research

Abstract � Due to the growing importance of alignment, compliance and manageability issues, increased attention is being paid to architectures and architecture management recently. A holistic approach to enterprise architecture requires business related and information systems related artifacts to be equally treate d. This paper describes the extension of an existing approach to enterprise architecture and its implementation using a commercial metamodeling platform. In addition to the approach metamodels in general, special attention is paid to the linkages between different architecture layers, both in the underlying model and in its implementation. 1

This paper presents a method for enterprise modelling that enhances object-oriented modelling with concepts from Management Science. It includes a framework that provides a set of conceptually integrated partial models, each of which is suited to represent a particular perspective on the enterprise - a strategic, an organizational, and an information system perspective. While the conceptual foundation is provided by a common object model and a corresponding meta object model, the partial models have specialized semantics and provide intuitive notations. An overall process model fosters a coherent coordination of the various activities to be performed during analysis and design. The activities themselves are described in detail referring to the partial models and to analysis and design techniques, some of which are integrated in the overall object model. The framework is accompanied by an integrated tool environment which controls a model's integrity, provides various analysis...

Enterprise models provide various abstractions that help with the design of corporate informa- tion systems which are in line with a company's organisation and its long term strategy. At the same time an enterprise model can be instantiated into a corporate knowledge base. Different from other methods for enterprise modelling, MEMO puts special emphasis on modelling languages. The visual languages provide intuitive abstractions for various observers. Against the background of the requirements imposed by enterprise modelling, the paper presents an extensible framework for specialised modelling languages and their reconstruction for an integrated design environment. The languages are defined in metamodels which in turn are instances of a common meta-metamodel. Similar to a technical language, they provide concepts that help with analysing and structuring a domain with respect to a specific task. The languages share common concepts which allow for a tight integration of the various parts ...

Abstract. Many different types of models are used in various scientific and engineering fields, reflecting the subject matter and the kinds of understanding that is sought in each field. Conceptual modeling techniques in software and information systems engineering have in the past focused mainly on describing and analyzing behaviours and structures that are implementable in software. As software systems become ever more complex and densely intertwined with the human social environment, we need models that reflect the social characteristics of complex systems. This chapter reviews the approach taken by the i* framework, highlights its application in several areas, and outlines some open research issues. 1 Why Social Modeling In many scientific and engineering disciplines, the principles, premises, and objectives of the field are embedded in and manifested through the models that are the daily conceptual tools of the profession. The models reflect the kinds of understanding that is sought by practitioners of the field. In software and information