## 1996

J.W.G.M. Hubbers, and A.H.M. ter Hofstede. An Investigation of the Formal Foundations of Object-Oriented Conceptual Data Modeling. Technical report, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1996, To appear.

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E. Hoenkamp, L. Schomaker, P. van Bommel, C.H.A. Koster, and Th.P. van der Weide. Profile: A Proactive Information Filter. Technical report: CSI-N9602, February, Radboud University Nijmegen, 1996.

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Information Systems. Publication List 1991-1996. Technical report: CSI-N9603, March, Radboud University Nijmegen, 1996.

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J.W.G.M. Hubbers, and P. van Bommel. Using Graph Rewrite Rules in MISS. Technical report: CSI-N9604, May, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1996.

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A.I. Bleeker. Informatie zoeken op inhoud: de volgende stap. Technical report: CSI-N9605, May, Radboud University Nijmegen, 1996.

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Maristella Agosti, and Araminte Bleeker. Indexing and Evaluation: Two Main Problems in Content-based Multimedia Retrieval. Technical report: CSI-N9606, July, Radboud University Nijmegen, 1996.

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Gyï¿½rgy Kovï¿½cs, and P. van Bommel. Overview of F-logicfrom Database Transformation Perspective. Technical report: CSI-N9607, September, Radboud University Nijmegen, 1996.

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M.C.A. Devillers. The Binary Decision Machine. Technical report: CSI-N9609, October, Radboud University Nijmegen, 1996.

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P.J.M. Frederiks, and Th. P. A Note on Valid Instance Categoriesfor Conceptual Data Modeling. Technical report: CSI-N9610, December, Radboud University Nijmegen, 1996.

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P.J.M. Frederiks, and Th.P. van der Weide. Verification and Design for Information Architectures. Technical report: CSI-N9611, December, Radboud University Nijmegen, 1996.

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P.J.M. Frederiks, and Th.P. van der Weide. From a File-Oriented View to an Object-Oriented View. Technical report: CSI-R9601, January, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1996.

The last three decades the architecture of information systems has evolved from file-oriented, via data-oriented and communication-oriented towards an object-oriented view. Hand in hand with this architectural evolution the way a user communicates with the information system is changed. In this paper we discuss the relation between the different architectures and their associated man-machine communication. We introduce the concept of information grammar, and show that this grammar can be seen as a common point of convergence. Together with the evolution, we can identify an evolution of methods for information system development. The construction of an information grammar is also addressed in this paper.

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P.J.M. Frederiks, C.H.A. Koster, and Th.P. van der Weide. Validation of Object-Oriented Analysis Models using Informal Language. Technical report: CSI-R9609, May, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1996.

In this paper a conceptual model for object-oriented analysis is introduced. Three submodels are described which can be seen as milestones during the analysis phase. Each (sub)model has a corresponding paraphrasing mechanism which may be used (1) to provide a description of the structure of the model and (2) to generate sample instantiations. This paraphrasing mechanism is intended to enable the domain expert to validate the model by sentences in (semi-)natural language.

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P.J.M. Frederiks, and Th.P. van der Weide. Cognitive Requirements for Natural Language Based Conceptual Modeling. Technical report: CSI-R9610, June, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1996.

In this paper we discuss the consequences of a natural language based modeling process for those who are involved in this process, i.e. domain experts and system analysts. For both domain experts and system analysts the cognitive requirements in a natural language based conceptual modeling process are presented as axiom-like requirements.

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J.J. Sarbo. Representing subsumption by concept lattices. Technical report: CSI-R9611, June, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1996.

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B.P.F. Jacobs. Hybrid Systems of Coalgebras plus Monoid Actions. Technical report: CSI-R9614, September, Radboud University Nijmegen, 1996.

Hybrid systems combine discrete and continuous dynamics. Weintroduce a semantics for such systems consisting of a coalgebratogether with a monoid action. The coalgebra captures the (discrete)operations on a state space that can be used by a client (like inthe semantics of ordinary (non-temporal) object-oriented systems).The monoid action captures the influence of time on the state space,where the monoids that we consider are the natural numbers monoid$(\NNO,0,+)$ of discrete time, and the positive reals monoid $({\BbbR}_{\geq 0},0,+)$ of real time. Based on this semantics we develop ahybrid specification formalism with timed method applications: itinvolves expressions like $\sans{s}.\sans{meth}@\alpha$, with the following meaning: in state$\sans{s}$ let the state evolve for $\alpha$ units of time(according to the monoid action), and then apply the (coalgebraic)method $\sans{meth}$. In this formalism we specify various(elementary) hybrid systems, investigate their correctness, anddisplay their behaviour in simulations. We further define a suitable notion of homomorphism between ourhybrid models (of coalgebras plus monoid actions), in such a waythat minimal realizations (of the specified behaviour) appear asterminal models. We identify the terminal models of our examplespecifications, and give general constructions. This leads to aninvestigation of various topics related to terminality:bisimilarity, behaviour-realization adjunctions, refinement (with acoinductive proof method for correctness) and inheritance. In afinal section we briefly discuss non-homogeneous hybrid systems(with continuous inputs).

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J.W.G.M. Hubbers, and A.H.M. ter Hofstede. On the Concepts Underlying Object-Oriented Conceptual Data Modeling. Technical report: CSI-R9615, September, Computing Science Institute, University of Nijmegen, Nijmegen, The Netherlands, 1996.

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G. Kovï¿½cs, and P. van Bommel. From Conceptual Model to OO Database via Intermediate Specification. Technical report: CSI-R9617, October, Radboud University Nijmegen, 1996.

When designing underlying databases of information systems, data arefirst modelled on conceptual level and then the obtained conceptual data modelis transformed to a database.The focus of this paper is the transformation ofconceptual models into object-oriented database systems.Fora conceptual schema, consisting of an information structure and a set ofintegrity constraints,both the structure and the constraints have to be translated into thetarget environment.In our approach this mapping is captured within the frameworkof a two level architecture. Conceptual models are first mapped to abstract intermediate specifications,which are then transformed to database schemas in a given object-oriented target database environment (e.g. SQL3, ODMG).To express intermediate representations of conceptual modelswe use F-logic, a logic-based abstract specification language forobject-oriented systems.In the present paper we focus on the first step of the overall transformation,i.e. the mapping of conceptual models into F-logic.Several transformation alternatives are discussed,and a corresponding graphical notation for specifying transformationalternatives is provided.

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B.P.F. Jacobs. Behaviour-Refinement of Object-Oriented Specifications with Coinductive Correctness Proofs. Technical report: CSI-R9618, October, Radboud University Nijmegen, 1996.

A notion of refinement is defined in the context of coalgebraic specification of classes in object-oriented languages. It tells us whenobjects in a concrete'' class behave exactly like (or: simulate) objectsin an abstract'' class. The definition of refinement involves certain selection functions between procedure-inputs and attribute-outputs,which gives this notion considerable flexibility. Thecoalgebraic approach allows us to use coinductive proof methods inestablishing refinements (via (bi)simulations). This is illustrated inseveral examples.

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M.S. klein Gebbinck, and Th. E. Accurate Area Estimation by Data-Driven Decomposition of Mixed Pixels. Technical report: CSI-R9622, December, Radboud University Nijmegen, 1996.

There are many image processing applications where the area of anobject has to be estimated as accurately as possible. A well-knownexample is the area estimation of agricultural fields, which is ofgreat importance for the management of the agricultural subsidy systemof the European Union. The area of an object can be estimated usingboth classification, which allocates a pixel to a single class, anddecomposition, which divides a pixel between several classes. Sincedecomposition is better at handling mixed pixels---pixels comprisingmultiple classes---which are often found at object boundaries, areaestimation by decomposition is expected to be more accurate. To testthis hypothesis, a data-driven decomposition method was developed andapplied to a series of artificial satellite images of increasingcomplexity. Data-driven decomposition was able to estimate thepercentage of each component of a pixel with an average error of~5\%.Narrow structures were processed correctly, and isolated pixels weredetected using a simple threshold. A quantitative comparison with theresults of three other methods found in the literature showed that thearea estimates of data-driven decomposition were significantly moreaccurate. This study suggests that data-driven decomposition is anaccurate area estimation method which is worth further research usingreal satellite images.

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G. Kovï¿½cs, and P. van Bommel. Designing and Implementing OO Database Using Conceptual Data Modelling. Technical report: CSI-R9624, December, Radboud University Nijmegen, 1996.

The focus of this paper is the transformation of conceptual data models (suchas ER, NIAM, PSM) to object-oriented databases.This transformation is capturedwithin the framework of a two level architecture. Conceptual modelsare first mapped to abstract intermediate specifications, which arethen transformed to database schemas in a given object-orienteddatabase environment. This enables us to treat different target systemsin a uniform way. As final implementation environtments we consider object-orientedas well as object-relational DBMSs, including the SQL3 andODMG-93 standards. Intermediate representations are expressed in F-logic, a logic-basedabstract specification language for object-oriented systems. Several transformation alternatives are discussed in a formalcontext, resulting in a collection of design options.%A corresponding graphical notation for design options%is provided.

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P.J.M. Frederiks, and Th.P. van der Weide. Formalization, Integration, and Validation of Object-Oriented Analysis Models leading to an Information Grammar. Technical report: CSI-R9625, December, Radboud University Nijmegen, 1996.

In this paper the focus is on object-oriented analysis of information systems.We assume that the communication within an application domain can be describedby a logbook of events.In our view, the purpose of the analysis phase is to model the structure of this logbook.The resulting conceptual model is referred to as theinformation architecture, and is an integration of threeformal object-oriented analysis models with each a specificview on the application domain. Furthermore, the information architectureforms an abstraction of an underlying grammar, called the informationgrammar, for the communication within the application domain.This grammar can be used to validate the information architecturein a textual format by informed users. Furthermore, the information grammarcan be used to obtain the relevant data and processes of theapplication domain, and serves as a basis for the query language of userswith the information system.

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M.S. klein Gebbinck, and Th.E. Schouten. Application of Data-Driven Decomposition to Landsat-TM Images for Crop Area Estimation. Technical report: CSI-R9626, December, Radboud University Nijmegen, 1996.

An accurate crop area estimation method based on satellite remotesensing imagery is needed to manage the agricultural subsidy system ofthe European Union. The area estimator can use either classification,which allocates a pixel to a single class, or decomposition, whichdivides a pixel between several classes, to determine the ground covertype(s) a pixel is composed of. While in early days classification wasmuch used, recently the decomposition approach has gained moreinterest, however, only on a per pixel basis. In a previous study, wedeveloped the data-driven decomposition method, which used spatialinformation to guide the decomposition process; on artificialLandsat-TM images this method proved to be far more accurate thantechniques based on classification or pixel-based decomposition. Toinvestigate whether data-driven decomposition also results in animproved area estimation when using real satellite images, the area of17 agricultural lots was determined from a large scale topographicalmap. After co-registration with a corresponding Landsat-TM image,application of data-driven decomposition gave an estimation that wasequally or more accurate than the estimates of a similar method basedon classification in 14 of the 17 cases. Furthermore, data-drivenclassification also showed to be better suited for handling the smallboundary structures that separated the agricultural fields. Theseresults suggest that the accuracy of data-driven decomposition ishigher than that of an area estimator based on classification whendealing with agricultural fields.

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J.F. Groote, and J. Springintveld. Algebraic Verification of a Distributed Summation Algorithm. Technical report: CSI-R9627, December, Radboud University Nijmegen, 1996.

In this note we present an algebraic verification of Segall's Propagation of Information with Feedback (PIF) algorithm.This algorithm serves as a nice benchmark forverification exercises (see \cite{Chou,Va95,Hes96}).The verification is based on the methodology presented in \cite{GS95}and demonstrates its applicability to distributed algorithms.

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