IRIS Research Publications


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Journal

P. van Bommel, and Gy.and Micsik Kovács. Transformation of database populations and operations from the conceptual to the internal level. In: Information Systems, Nr: 2, Vol: 19, Pages: 175-191, 1994.

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P.D. Bruza, and L.C. van der Gaag. Index Expression Belief Networks for Information Disclosure. In: International Journal of Expert Systems, Nr: 2, Vol: 7, Pages: 107-138, 1994.

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P. van Bommel. Experiences with EDO: an Evolutionary Database Optimizer. In: Data & Knowledge Engineering, Vol: 13, Pages: 243-263, 1994.

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P. van Bommel, C.B. Lucasius, and Th.P. van der Weide. Genetic Algorithms for Optimal Logical Database Design. In: Information and Software Technology, Nr: 12, Vol: 36, Pages: 725-732, 1994.

The focus of this paper is database design using automated database design tools or more general CASE tools. We present a genetic algorithm for the optimization of (internal) database structures, using a multi-criterion objective function. This function expresses conflicting objectives, reflecting the well-known time/space trade-off. This paper shows how the solution space of the algorithm can be set up in the form of tree structures (forests), and how these are encoded by a simple integer assignation. Genetic operators (database transformations) defined in terms of this encoding behave as if they manipulate tree structures. Some basic experimental results produced by a research prototype are presented.

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J.L.H. Oei, H.A. (Erik) Proper, and E.D. Falkenberg. Evolving Information Systems: Meeting the Ever-Changing Environment. In: Information Systems Journal, Nr: 3, Vol: 4, Pages: 213-233, 1994.

To meet the demands of organisations and their ever changing environment, information systems are required which are able to evolve to the same extent as organisations do. Such a system has to support changes of all time- and application-dependent aspects.

In this paper, requirements and a conceptual framework for evolving information systems are presented. This framework includes an architecture for such systems, and a revision of the traditional notion of update. Based on this evolutionary notion of update (recording, correction, and forgetting) a state-transition-oriented model on three levels of abstraction (event level, recording level, correction level) is introduced. Some examples are provided to illustrate the conceptual framework for evolving information systems.

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I. Kwaaitaal, M. Hoogeveen, and Th.P. van der Weide. A reference model for the impact of standardization on multimedia database management systems. In: Computer Standards and Interfaces, Vol: 16, Pages: 45-54, 1994.

This article discusses the standardization of MDBMSs which is needed to keep pace with rapid developments in the area of multimedia systems. A reference model for the impact of standardization on MDBMSs is presented which summarises the result of a survey of relevant standards. The reference model is used to identify standardization gaps. Currently, one of the most important gaps is the lack of a standard multimedia database language for definition and manipulation of multimedia data.

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H.A. (Erik) Proper, and Th.P. van der Weide. EVORM - A Conceptual Modelling Technique for Evolving Application Domains. In: Data & Knowledge Engineering, Vol: 12, Pages: 313-359, 1994.

In this paper we present EVORM, a data modelling technique for evolving application domains. EVORM is the result of applying a general theory for the evolution of application domains to the object role modelling technique PSM, a generalisation of ER, EER, FORM and NIAM.

First the general theory is presented. This theory describes a general approach to the evolution of application domains, abstracting from details of specific modelling techniques. This theory makes a distinction between the underlying information structure and 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.

After a (short) introduction to PSM, this general theory is applied, resulting in EVORM. Besides having a right of its own, the usefulness of the general theory is demonstrated by interpreting its abstract results, resulting in more intuitive rules for EVORM.

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J.J. Sarbo. Grammar transformations for optimizing backtrack parsers. In: Computer Languages, Nr: 2, Vol: 20, Pages: 89-100, 1994.

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Book

H.A. (Erik) Proper. A Theory for Conceptual Modelling of Evolving Application Domains. University of Nijmegen, 1994, ISBN 909006849X.

Nowadays, the financial prosperity of an organisation depends increasingly on its ability to change. Flexibility allows an organisation to be more competitive in the global market, thus improving its chances of survival. This means that organisations must be able to adapt quickly to producing new or different products, changes in the primary process of an organisation that result from ever higher and changing consumer needs. Flexible behaviour of organisations leads to rapidly changing, any information system supporting such needs must also be highly flexible.

In this thesis, we first develop a general (modelling technique independent) theory for evolving information systems. Then we apply this theory to existing modelling techniques, thus providing a quality check on the general theory.

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Conference

P. van Bommel. Database Design Modifications based on Conceptual Modelling. In: Information Modelling and Knowledge Bases V: Principles and Formal Techniques, Amsterdam, The Netherlands, EU, Edited by: H. Jaakkola, H. Kangassalo, T. Kitahashi, and A. Márkus. Pages: 275-286, IOS Press, Amsterdam, The Netherlands, EU, 1994.

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P. van Bommel, C.B. Lucasius, and Th.P. van der Weide. Pool Heuristics in Evolutionary Database Optimization. In: Proceedings of the International Conference on Information Systems and Management of Data (CISMOD 94), Edited by: N. Prakash. Pages: 76-90, October, 1994.

This paper describes several new results of the project C2I at the University of Nijmegen, The Netherlands. The focus of C2I is the transformation of data models from the conceptual to the internal level. Several aspects are involved, such as data structures, operations, populations (values) and integrity constraints. Special emphasis is given to optimization of data structures with respect to the trade-off between response time and storage space.

New results include PHSL, an abstract Pool Heuristic Specification Language for expressing the basic actions in advanced (evolutionary) optimization strategies. Furthermore, the applicability of the approach to traditional Codasyl network models is illustrated (it has already been shown that the approach is applicable to relational and nested-relational models).

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P. van Bommel. Implementation Selection for Object-Role Models. In: Proceedings of the First International Conference on Object-Role Modelling (ORM-1), Edited by: T.A. Halpin, and R. Meersman. Pages: 103-112, July, 1994.

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S.J. Brouwer, C.L.J. Martens, G.H.W.M. Bronts, and H.A. (Erik) Proper. Towards a Unifying Object Role Modelling Approach. In: Proceedings of the First International Conference on Object-Role Modelling (ORM-1), Edited by: T.A. Halpin, and R. Meersman. Pages: 259-273, July, 1994, ISBN 0867765658.

In this article we briefly present the idea of defining a kernel for object role modelling techniques, upon which different drawing styles can be based. We propose such a kernel (the ORM kernel) and define, as a case study, an ER and a NIAM drawing style on top of it. One of the prominent advantages of such a kernel is the possibility to build a CASE-tool supporting multiple methods. Such a CASE-tool would allow users with different methodological backgrounds to use it and view the modelled domains in terms of their favourite method. This is illustrated using a running example of a concrete domain in which we use the ORM kernel in combination with the NIAM and ER drawing style.

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P.D. Bruza, and T.W.C. Huibers. Investigating aboutness axioms using information fields. In: Proceedings of the 17th annual international ACM SIGIR conference on Research and development in information retrieval, Dublin, Ireland, EU, Edited by: W.B. Croft, and C.J. van Rijsbergen. Pages: 112-121, July, Springer, 1994, 038719889X.

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P.D. Bruza, and J.J. IJdens. Efficient Probabilistic Inference through Index Expression Belief Networks. In: Proceedings of the Seventh Australian Joint Conference on Artificial Intelligence (AI94), Pages: 592-599, World Scientific, Melbourne, Victoria, Australia, 1994.

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C.A.J. Burgers, H.A. (Erik) Proper, and Th.P. van der Weide. An Information System organized as Stratified Hypermedia. In: CISMOD94, International Conference on Information Systems and Management of Data, Edited by: N. Prakash. Pages: 159-183, October, 1994.

In this paper we investigate the relation between modern hypertext approaches and conventional data modelling techniques, such as PSM. We show how query formulation in a traditional information system can be regarded as a stratified hypermedia featuring two levels of abstraction. The first level of abstraction covers the structure of the stored information, and the second level the information itself.

The investigations provide us with the mechanism of query by navigation as a novel avenue for improved query formulation in information systems.

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E.D. Falkenberg, and J.L.H. Oei. Meta Model Hierarchies from an Object-Role Modelling Perspective. In: Proceedings of the First International Conference on Object-Role Modelling (ORM-1), Edited by: T.A. Halpin, and R. Meersman. Pages: 218-227, July, 1994.

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A.H.M. ter Hofstede, H.A. (Erik) Proper, and Th.P. van der Weide. Supporting Information Disclosure in an Evolving Environment. In: Proceedings of the 5th International Conference DEXA`94 on Database and Expert Systems Applications, Athens, Greece, EU, Edited by: D. Karagiannis. Lecture Notes in Computer Science, Vol: 856, Pages: 433-444, September, Springer, 1994, ISBN 3540584358.

Even if high-level query languages are used, query formulation may cause problems. This is notably so in case of large and complex application domains. Typical examples of these kinds of application domains are evolving application domains. In an evolving application domain not only populations may change, but also the conceptual schema. Even more, the history of the application domain should be recorded, and be retrievable.

This paper focuses on support for query formulation in the context of large conceptual schemata. The solution presented uses the idea of query-by-navigation in conjunction with query-by-construction. First this idea is illustrated by means of some examples, then it is formally defined.

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A.H.M. ter Hofstede, and Th.P. van der Weide. Fact Orientation in Complex Object Role Modelling Techniques. In: Proceedings of the First International Conference on Object-Role Modelling (ORM-1), Edited by: T.A. Halpin, and R. Meersman. Pages: 45-59, July, 1994.

A number of proposals have been made to extend conventional data modelling techniques with concepts for modelling complex object structures, such as power types, sequence types and schema types. A drawback of the introduction of such new concepts is that the original simplicity of a single populatable concept is lost. In this paper we will show how a new kind of constraint, the extensional uniqueness constraint, can overcome this problem. Another advantage of this constraint is that it enables a less rigid identification schema. The usefulness of this new constraint is demonstrated in some concrete modelling situations.

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A.H.M. ter Hofstede, H.A. (Erik) Proper, and Th.P. van der Weide. A Conceptual Language for the Description and Manipulation of Complex Information Models. In: Seventeenth Annual Computer Science Conference, Edited by: G. Gupta. Australian Computer Science Communications, Vol: 16, Pages: 157-167, January, University of Canterbury, Christchurch, New Zealand, 1994, ISBN 047302313.

Conceptual data modelling techniques aim at the representation of data (structures) at a high level of abstraction. This implies that conceptual data modelling techniques should not only be capable of representing complex structures in a natural way, but also the rules (constraints) that must hold for these structures. Contemporary data modelling techniques, however, do not provide a language which, on the one hand, has a formal semantics and, on the other hand, leads to natural looking expressions. In this paper, an informal introduction to such a language (LISA-D) for the data modelling technique (PSM), is presented. PSM is a generalisation of object-role models (such as ER, NIAM and FORM).

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P.D. Bruza, and T.W.C. Huibers. Detecting the Erosion of Hierarchic Information Structures. In: Proceedings of the Document Processing 94 Workshop, Edited by: M. Murata, and H. Gallaire. April, 1994.

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T.W.C. Huibers, B. van Linder, and P.D. Bruza. Een Theorie voor het Bestuderen van Information Retrieval Modellen In Dutch. In: Informatiewetenschap 1994: Wetenschappelijke Bijdragen aan de Derde StinfoN Conferentie, Edited by: L.G.M. Noordman, and W.A.M. de Vroomen. Pages: 85-102, December, Stichting StinfoN, 1994.

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J.J. Sarbo, and J.I. Farkas. Concept Sublattices. In: Proceedings of the European Conference on Machine Learning (ECML`94), 1994.

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Reports

P. van Bommel. A View Algebra for Object-Role Models. Technical report: CSI-R9407, June, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1994.

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T.W.C. Huibers, and P.D. Bruza. Situations, a General Framework for Studying Information Retrieval. Technical report, March, Utrecht University, 1994.

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J.W.G.M. Hubbers. Structuur FOP-adviesapplicatie. Technical report, ABN/AMRO-bank, The Netherlands, 1994, In Dutch.

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J.L.H. Oei, and E.D. Falkenberg. Harmonization of Information Systems Modelling and Specification Techniques. Technical report: CSI-R9407, Technical University Twente, The Netherlands, 1994.

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H.A. (Erik) Proper. ConQuer-92 - The revised report on the conceptual query language LISA-D. Technical report, Asymetrix Research Laboratory, University of Queensland, Brisbane, Queensland, Australia, 1994.

In this report the conceptual query language ConQuer-92 is introduced. This query language serves as the backbone of InfoAssistant's query facilities. Furthermore, this language can also be used for the specification of derivation rules (e.g. subtype defining rules) and textual constraints in InfoModeler.

This report is solely concerned with a formal definition, and the explanation thereof, of ConQuer-92. The implementation of ConQuer-92 in SQL-92 will be treated in a separate report.

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H.A. (Erik) Proper. An Overview of Computer Supported Query Formulation. Technical report, Asymetrix Research Laboratory, University of Queensland, Brisbane, Queensland, Australia, 1994.

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 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.

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H.A. (Erik) Proper. Generating Significant Examples for Conceptual Schema Validation. Technical report, Asymetrix Research Laboratory, University of Queensland, Brisbane, Queensland, Australia, 1994.

This report bases itself on the idea of using concrete examples to verify conceptual schemas, and in particular cardinality constraints. When novice ORM modellers model domains, the selection of proper cardinality constraints for relationship types is quite often prone to errors. In this report we propose a mechanism for the generation of significant examples for selected subschemas. The generated examples are significant in the sense that they illustrate the possible combinations of instances that are allowed with respect to the cardinality constraints on the in-volved relationship types.

In this report we firstly provide a brief informal discussion of the basic idea. Then we present a syntactic mechanism to select the subschema for which example instances are to be generated. This is followed by the actual example generation algorithm itself. We will also present, as a spin-off, an algorithm that allows us to detect possible flaws in the conceptual schema by calculating the number of instances that can be used to populate the types in the schema.

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H.A. (Erik) Proper. Introduction to Formal Notations. Technical report, Asymetrix Research Laboratory, University of Queensland, Brisbane, Queensland, Australia, 1994.

In this report we provide a short discussion on the formal notations used in the reports from the research lab. The intention is that this documents evolves in the course of time. This evolution is driven by two sources. Firstly, any unclarities in the used notations, either due to terse explanation or limitations in the existing knowledge in the fields of formalisation. Secondly, due to the possible introduction of new notations and formalisms in new reports.

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H.A. (Erik) Proper, and Th.P. van der Weide. A General Theory for the Evolution of Application Models - Full version. Technical report, Department of Computer Science, University of Queensland, Brisbane, Australia, 1994.

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.

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H.A. (Erik) Proper. Interactive Query Formulation using Point to Point Queries. Technical report, Asymetrix Research Laboratory, University of Queensland, Brisbane, Queensland, Australia, 1994.

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, and query by construction. In this article we propose the point to point query mechanism that can be combined with the existing mechanism into an unprecedented computer supported query formulation mechanism.

In a point to point query a path through the information structure is build. This path can then be used to formulate more complex queries. A point to point query is typically useful when users know some object types which are relevant for their information need, but do not (yet) know how they are related in the conceptual schema. Part of the point to point query mechanism is therefore the selection of the most appropriate path between object types (points) in the conceptual schema. This article both discusses some of the pragmatic issues involved in the point to point query mechanism, and the theoretical issues involved in finding the relevant paths between selected object types.

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H.A. (Erik) Proper. Interactive Query Formulation using Query By Navigation. Technical report, Asymetrix Research Laboratory, University of Queensland, Brisbane, Queensland, Australia, 1994.

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 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 query by construction, and is the constructive phase of the query formulation process.

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H.A. (Erik) Proper. Interactive Query Formulation using Spider Queries. Technical report, Asymetrix Research Laboratory, University of Queensland, Brisbane, Queensland, Australia, 1994.

Effective information disclosure in the context of databases with a large con-ceptual schema is known to be a non-trivial problem. In particular the formula-tion 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 article we propose the spi-der query mechanism as a final corner stone for an easy to use computer supported query formulation mechanism for InfoAssisant.

The basic idea behind a spider query is to build a (partial) query of all information considered to be relevant with respect to a given object type. The result of this process is always a tree that fans out over existing conceptual schema (a spider).

We also provide a brief discussion on the integration of the spider quer mech-anism with the existing query by navigation, query by construction, and point to point query mechanisms.

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