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.

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This paper develops a model for research and practice of strategic management of information technology. The model, termed the Strategic Alignment Model, is defined in terms of four domains of strategic choice: business strategy; information technology strategy; organization infrastructure and processes; and information technology infrastructure and processes-- each with its constituent dimensions. The model is conceptualized in terms of two fundamental characteristics of strategic management: strategic fit (i.e., the interrelationships between external and internal domains) and functional integration (i.e., integration between business and functional domains). A set of propositions is developed based on this model with implications for research and management practice. Acknowledgements. The authors would like to acknowledge the contributions to

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.

Architectural patterns are a key concept in the field of software architecture: they offer well-established solutions to architectural problems, help to document the architectural design decisions, facilitate communication between stakeholders through a common vocabulary, and describe the quality attributes of a software system as forces. Regrettably, finding and applying the appropriate architectural patterns in practice still remains largely ad-hoc and unsystematic. This is due to the lack of consensus in the community with respect to the “philosophy ” and granularity of architectural patterns, as well as the lack of a coherent pattern language. In this paper we attempt to establish common ground in the architectural patterns community by proposing a pattern language that acts as a superset of the existing architectural pattern collections and categorizations. This language is particularly focused on establishing the relationships between the patterns and performs a categorization based on the concept of “architectural views”. 1

ABSTRACT: This paper is concerned with the engineering of systems that are themselves comprised of other com-ponent systems, and where each of the component systems serves organizational and human purposes. These com-ponent purposes may be locally managed and optimized independently, or nearly so, of the objectives to be met by the composite system. There are a number of inherent characteristics of these systems, and such related terms as systems of systems (SOS) or federations of systems (FOS) or federated systems of systems (F-SOS) are often used to characterize them. It is asserted that the resultant systems generally possess the characteristics of complex adap-tive systems. We provide an overview of the literature describing these engineering efforts and provide plausible strategies for systems engineering and management of SOS and FOS that are based on the principles of a “new fed-eralism”. Finally, the implications of these plausible SOS and FOS systems engineering and management concepts are discussed with emphasis on evolutionary acquisition in the style of DoD and Intelligence Community related programs.

…for its continued progress in building a culture of regional cooperation and decision-making to increase the quality of life of member nations, The development of a Regional Spatial Data Infrastructure (Regional SDI) is much more challenging than the development of a National SDI initiative within a nation. This is mainly because of the voluntary nature of cooperation at a multi-national level and participation in a Regional SDI initiative. As a result, despite considerable interest and activities, the development of an effective and comprehensive Asia-Pacific Regional Spatial Data Infrastructure (APSDI) is hampered by a lack of support from member nations which results in this initiative remaining only an innovative concept. Based on this situation, the aim of this research is to design an improved conceptual model for Regional SDI and an implementation strategy. It is proposed that this problem can be partly addressed by increasing the level of awareness about the nature and value of SDIs; improving the SDI conceptual model to better meet the needs of nations; and by identifying key factors that facilitate development by better understanding the

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.

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...