Models and their Foundational Framework

The term model is mainly used in two meanings which are considered to be different: a model of a problem domain as a conceptualisation; a model of a set of formulas as an interpretation in which every formula within this set is true. A general theory of models has not yet been developed. H. Stachowiak proposes a phenomenal approach and ‘defines’ models by their properties of mapping, truncation and pragmatics. Meanwhile, a notion of the model has been developed. At the same time, it seems that there are rather different understandings of model in sciences and especially Mathematical Logics. Sciences treat models as reflections of origins. Mathematical logics considers models as an instantiation in which a set of statements is valid. So, mathematical model theory is often considered to be a completely different approach to modelling. We realise however that mathematical model theory is only a specific kind of modelling. We show that the treatment of models in logics and in sciences can be embedded into a more general framework. So, the theory of models is based on a separation of concern or orientation

A Formal Approach to High Quality Software Design and Development

Software design and development coexist and co-evolve with quality provision, assessment and enforcement. However, most and also modern research ``provides only bread and butter lists of useful properties without giving a systematic structure for evaluating them''. Software engineers have been putting forward several three-score quantities of metrics for software products, processes and resources whereas a theoretical foundation is still missing. This preprint proposes a framework to quality property specification, to quality control, the quality utilisation and quality establishment. Our framework has a theoretical basis that is adaptable to all stages of software development

Intention-Driven Screenography

The visual design development of Web Information Systems is a complex task. At present, the process is mainly based on experiences and seems to be an immovable part of art. Typically, occurs a late consideration of graphical issues that results in inflexibility and cause problems for extension and change management. Database and software systems are mainly based on development phases such as requirement acquisition and elicitation and conceptual modelling. Moreover, users, their preferences and portfolio are taken into consideration. We show in this preprint that these approaches can be generalised to website presentation. We use methods developed for programming in the large, e.g. patterns. We can map patterns to conceptualisations of web page layout, i.e. grids. Patterns shall help us to reuse concepts. This paper introduces the concept of pattern and clarifies their structure and task for the whole development. Because the WIS development process is based on six dimensions, we initially introduce development dimensions and show the seamless integration of the pattern-based approach. We call the art of website layout screenography. Screenography extends web application engineering by scenographic and dramaturgic aspects and intends to support the interaction between system and user. Screenography aims at an individualised, decorated playout in consideration of intention, user profiles and portfolios, provider aims, context, equipment, functionality and the storyline progress. The users orientation of WIS requires the deep integration of user concerns, tasks and expectations into screenography. Therefore, this paper develops concepts of intention- driven screenography

Exceptions in Information Systems

The concept of exception has been defined in diverse ways. We relate exceptions to computational transactions and to control constructs. Our view of a transaction is very broad, and we consider transactional exceptions to be instances of undefined function values. By giving different interpretations to undefined we arrive at a classification of transactional exceptions. Our primary interest is in information systems, i.e., in database transactions, and in processes that consist of such transactions. In the database context we show that liberal treatment of exceptions is simpler than total quality management for consistency based on a set of constraints. We refer to control operations that link transactions into processes as actions. Actions tend to be time-related, and time Petri nets provide actions with semantics. The time Petri net representation indicates where exceptions can arise. We also consider high-level monitors for the detection of exceptions. Although our emphasis is on detection of exceptions, their handling is also discussed

An Approach to Conceptual Schema Evolution

In this work we will analyse conceptual foundations of user centric content management. Content management often involves integration of content that was created from different points of view. Current modeling techniques and especially current systems lack of a sufficient support of handling these situations. Although schema integration is undecideable in general, we will introduce a conceptual model together with a modeling and maintenance methodology that simplifies content integration in many practical situations. We will define a conceptual model based on the Higher-Order Entity Relationship Model that combines advantages of schema oriented modeling techniques like ER modeling with element driven paradims like approaches for semistructured data management. This model is ready to support contextual reasoning based on local model semantics. For the special case of schema evolution based on schema versioning we will derive the compatibility relation between local models by tracking dependencies of schema revisions. Additionally, we will discuss implementational facets, such as storage aspects for structurally flexible content or generation of adaptive user interfaces based on a conceptual interaction model

Usage-Based Storyboarding for Web Information Systems

On a high level of abstraction a Web Information System (WIS) can be described by a storyboard, which in an abstract way specifies who will be using the system, in which way and for which goals. While syntax and semantics of storyboarding has been well explored, its pragmatics has not. This paper contributes the first step towards closing this gap by analysing the usage of WISs. Starting from a classification of intentions we first present life cases, which capture observations of user behaviour in reality. We discuss the facets of life cases and present a semi-formal way for their documentation. Life cases can be used in a pragmatic way to specify a story space, which is an important component of a storyboard. In a second step we complement life cases by user models that are specified by various facets of actor profiles that are needed for them. We analyse actor profiles and present a semi-formal way for their documentation. We outline how these profiles can be used to specify actors, which are an important component of a storyboard. Finally, we analyse contexts and the way they impact on life cases, user models and the storyboard

Web Information Systems: Usage, Content, and Functionally Modelling

The design of large-scale data-intensive web information systems (WIS) requires a clear picture of the intended users and their behaviour in using the system, a support of various access channels and the technology used with them, and an integration of traditional methods for the design of data-intensive information systems with new methods that address the challenges arising from the web-presentation and the open access. This paper presents the conceptual modelling parts of a methodology for the design of WISs that is based on an abstract abstraction layer model (ALM). It concentrates on the two most important layers in this model: a business layer and a conceptual layer. The major activities on the business layer deal with user profiling and storyboarding, which addresses the design of an underlying application story. The core of such a story can be expressed by a directed multi-graph, in which the vertices represent scenes and the edges actions by the users including navigation. This leads to story algebras which can then be used to personalise the WIS to the needs of a user with a particular profile. The major activities on the conceptual layer address the support of scenes by modelling media types, which combine links to databases via extended views with the generation of navigation structures, operations supporting the activities in the storyboard, hierarchical presentations, and adaptivity to users, end-devices and channels. Adding presentation style options this can be used to generate the web-pages that will be presented to the WIS users