Auflistung nach Autor:in "Schewe, Klaus-Dieter"
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- KonferenzbeitragThe challenges in web information systems development(Information systems technology and its applications, ISTA' 2005, 2005) Schewe, Klaus-DieterThe development of web information systems has led to new challenges regarding the scalability and expressiveness of methods. In particular, as systems become large, it becomes decisive to guarantee consistency and integrity of designs. The paper introduces the challenges in a step-by-step way and indicates how to cope with them. First, the conceptual model of a WIS as a collection of media types, i.e. extended views, is introduced. In this context the adaptivity to users, channels and devices will also be discussed. Secondly, WIS development is discussed on a higher level of abstraction dealing with tasks, roles, user profiles and storyboards. At this level equational reasoning can be applied. Finally, both levels of abstraction are combined leading to further challenges by using dynamic and deontic logics.
- KonferenzbeitragA deontic logic for group-oriented web information systems(EMISA 2004 – Informationssysteme im E-Business und E-Government, Beiträge des Workshops der GI-Fachgruppe EMISA (Entwicklungsmethoden für Informationssysteme und deren Anwendung), 2004) Schewe, Klaus-Dieter; Thalheim, Bernhard; Kaschek, RolandGroup-oriented web information systems (GWISs) are web-based dataintensive systems that are used by a group of people in order to fulfill common tasks. In particular, there are different roles for the users, each associated with some rights and obligations. The group orientation implies that some of these obligations and rights depend on actions done by other roles. In this article a deontic logic for formulating and reasoning about such obligations and rights is presented.
- KonferenzbeitragIntegration and cooperation of media types(Information systems technology and its applications, ISTA' 2005, 2005) Ma, Hui; Schewe, Klaus-Dieter; Thalheim, BernhardMedia types are a core design construct in the co-design approach for web information systems (WISs). They provide abstract means for describing content, functionality, context and adaptivity to user preferences and intentions, end-devices, and channel limitations. Basically, a media type is a view that is extended by operations and cohesion. Thus, the problem of integrating these extended views is a core design problem for WISs. In this paper we develop formal transformation rules for media type integration that are embedded in a pragmatic method addressing how they should be applied for integration. They extend view integration rules in such a way that operations and cohesion are dealt with simultaneously. Cooperation provides an alternative to integration in which the integrated view is only virtual, i.e. the constituating views are kept and exchange functions are designed to provide the same functionality as if the views were integrated. We show that the transformation rules can also be applied to the problem of media type cooperation.
- KonferenzbeitragIntention-Driven Screenography(Information systems technology and its applications – 6th international conference – ISTA 2007, 2007) Moritz, Thomas; Noack, René; Schewe, Klaus-Dieter; Thalheim, BernhardThe design and reification of Web Information Systems is a complex task, for which many integrated development methods have been proposed. While all these methods ultimately lead to the construction of web pages, very little attention is paid to the layout of these pages. The work report in this paper amalgamates knowledge from art, cognitive psychology and scenography in an attempt to systematise WIS layout and thus to complement development methods with this respect. We discuss principles and rules for page layout that originate from knowledge of visual perception and communication, and then investigate how layout can support the intentions associated with the WIS. This amounts to guidelines for partitioning pages and using layout objects, colour, light and texture to obtain rhythm, contrast and perspective as the carriers for web page comprehension.
- KonferenzbeitragModelling actors and stories in web information systems(Information systems technology and its applications, 3rd international conference ISTA'2004, 2004) Schewe, Klaus-Dieter; Thalheim, Bernhard; Zlatkin, SergiyThe design of web information systems (WISs) requires a clear picture of the intended users and their behaviour. WIS users are called actors and classified according to their roles, intentions and behaviour. This leads to various propositional and deontic constraints on the story space, i.e. the abstract specification of WIS locations and activities associated with them. The knowledge obtained from the modelling of actors can be used to personalise the story space to the needs of a particular actor.
- KonferenzbeitragUsing XML to support media types(Information systems technology and its applications, ISTA' 2005, 2005) Kirchberg, Markus; Schewe, Klaus-Dieter; Tretiakov, AlexeiThe eXtensible Markup Language (XML) has drawn significant attention in research and practice of databases and web-based information systems. At the same time, lots of work has been investigated in conceptual modelling for web-based information systems which is at most loosely coupled with XML. One such research direction has led to the theory of media types, which has proven itself to be useful for the design and development of large and maintainable web-based information systems. The research reported in this article investigates how XML and the theory of media types could be brought together, i.e. how XML could be used to support media types. It turns out that some of the striking features of media types are not yet well supported by XML. Therefore, severals extensions to XML such as subelements, update operations, schema updates, views, media elements and adaptivity will be suggested in this article in order to close this gap.