H. A. Proper

H. A. Proper

Effective information disclosure in the context of databases with a large conceptual schema is known to be a non-trivial problem. In particular the formulation of ad-hoc queries is a major problem in such contexts. Existing approaches for tackling this problem include graphical query interfaces, query by navigation, query by construction, and point to point queries. In this report we propose an adoption of the query by navigation mechanism that is especially geared towards the InfoAssistant product. Query by navigation is based on ideas from the information retrieval world, in particular on the stratified hypermedia architecture. When using our approach to the formulations of queries, a user will first formulate a number of simple queries corresponding to linear paths through the information structure. The formulation of the linear paths is the result of the {\em explorative phase} of the query formulation. Once users have specified a number of these linear paths, they may combine them to form more complex queries. Examples of such combinations are: concatenation, union, intersection and selection. This last process is referred to as {\em query by construction}, and is the {\em constructive phase} of the query formulation process.

H. A. Proper

Most present day organisations make use of some automated information system. This usually means that a large body of vital corporate information is stored in these information systems. As a result, an essential function of information systems should be the support of disclosure of this information. We purposely use the term {\em information disclosure} in this context. When using the term information disclosure we envision a computer supported mechanism that allows for an easy and intuitive formulation of queries in a language that is as close to the user's perception of the universe of discourse as possible. From this point of view, it is only obvious that we do not consider a simple query mechanism where users have to enter complex queries manually and look up what information is stored in a set of relational tables. Without a set of adequate information disclosure avenues an information system becomes worthless since there is no use in storing information that will never be retrieved.

P. D. Bruza, H. A. Proper

We are surrounded by an ever increasing amount of data that is stored in a variety of databases. In this article we will use a very liberal definition of \EM{database}. Basically any collection of data can be regarded as a database, ranging from the files in a directory on a disk, to ftp and web servers, through to relational or object-oriented databases. The sole reason for storing data in databases is that there is an anticipated need for the stored data at some time in the future. This means that providing smooth access paths by which stored information can be retrieved is at least as important as ensuring integrity of the stored information. In practice, however, providing users with adequate avenues by which to access stored information has received far less attention.

T. A. Barrett, H. A. Proper

Many of today's applications have an, almost tangible, monolithic nature. They are built as 'islands', purporting to be self contained, offering little or nothing in the way of integration with other applications. In the past, being large and self-contained may have eliminated the need to interact with other solutions to some extent. However, in the business environments of today the interaction with other applications becomes paramount. As a result of this, many ad-hoc point-to-point integration solutions have been built between different applications. This has already led to an 'application spaghetti' at many of our customer sites. Many of today's applications are poorly structured, which makes their responsiveness to business change sluggish. The application spaghetti with its plethora of point-to-point interfaces further inhibits the responsiveness to change.

H. A. Proper

This document has emerged out of Origin's past experiences with architecture-driven application development (AD2), and the need to further formalise and consolidate these experiences.

H. A. Proper, Th. P. van der Weide

In this article we focus on evolving information systems. First a delimitation of the concept of evolution is provided, resulting in a first attempt to a general theory for such evolutions. The theory makes a distinction between the underlying information structure at the conceptual level, its evolution on the one hand, and the description and semantics of operations on the information structure and its population on the other hand. Main issues within this theory are object typing, type relatedness and identification of objects. In terms of these concepts, we propose some axioms on the well-formedness of evolution. In this general theory, the underlying data model is a parameter, making the theory applicable for a wide range of modelling techniques, including object-role modelling and object oriented techniques.

R. D. T. Janssen, H. A. Proper, H. Bosma et al.

Today, there are millions of professionals worldwide acting as a designer, architect or engineer in the design, realization, and implementation of information systems. At this moment there is no well established and clearly identified body of knowledge that defines their profession in a "standard" way. In this article, we present the idea of developing an architecture method library. Such a library could play a pivotal role to further professionalize the field. The library contains project experiences, reference architectures, literature, proven methods, tools, etc. Access mechanisms allow the professional to use this body of knowledge. By giving it an open nature, it can be filled by professionals from different fields. Feedback mechanisms are possible to improve the contents of the library, for example by giving feedback on the method components in the library.