% $Id: ag.bib,v 1.120 2008/07/05 10:04:53 gogolla Exp gogolla $ @TECHREPORT{Coy:1979:Report, AUTHOR ="Wolfgang Coy and Claudio Moraga and Friedrich Abraham and Angelika Beese and Werner Bielefeld and Magdalena Bonsiepen and Martin Gogolla and Michael Land and Manfred Siebert", TITLE ="{Adaptive und Lernende Systeme - Bericht einer Projektgruppe Wintersemester 1978 - Sommersemester 1979}", INSTITUTION="{Universit{\"a}t Dortmund, Abteilung Informatik}", YEAR ="{1979}", type ="{Interne Berichte und Skripten}", abstract ="{ In der Projektgruppe ``Adaptive und Lernende Systeme'' wollten die Veranstalter eine M{\"o}glichkeit anbieten, das Problem des Lernens im Gebiet der formalen Sprachinferenz zu untersuchen. Nach einer einheitlichen Verarbeitung von Grundbeitr{\"a}gen aus der Literatur ist die Gruppe in der Lage, sich mit Inferenzalgorithmen zu besch{\"a}ftigen, einige zu entwickeln, in Form eines Programms zu testen und zu bewerten. Schlie\ss{}lich bietet sich die M{\"o}glichkeit, Algorithmen f{\"u}r Inferenz {\"u}ber verschiedenen Sprachen der Chomsky-, Petri- oder Lindenmayer-Sprachfamilien weiter zu untersuchen.}" } @MASTERSTHESIS{Gogolla:1980:Diplomarbeit, AUTHOR ="Martin Gogolla", TITLE ="{Eine Cha\-rak\-te\-ri\-sie\-rung von nicht-struk\-tu\-rier\-ten Flu\ss{}\-dia\-gram\-men}", SCHOOL ="{Universit{\"a}t Dortmund, Abteilung Informatik}", YEAR ="{1980}", abstract="{ In dieser Arbeit wird eine Formalisierung der Begriffe Flu\ss{}diagramm und Strukturiertheit eines Flu\ss{}diagramms angegeben, und es werden nicht-strukturierte Flu\ss{}diagramme {\"u}ber bestimmte Teilgraphen beschrieben. Flu\ss{}diagramme geben den Kontrollflu\ss{} von Programmen wieder, und Analysen des Programmablaufs k{\"o}nnen unter anderem zur Optimierung in Compilern, Umkehr{\"u}bersetzung von maschinennahen Programmen und Umwandlung von unstrukturierten Programmen in lesebare Form dienen. Fragestellungen nach der Ursache der Unstrukturiertheit sind sicherlich auch im Hinblick auf die Methodik der Programmierung von Interesse.}" } @TECHREPORT{Gogolla:1982:ReportDortmund140, AUTHOR ="Martin Gogolla and Klaus Drosten and Udo Lipeck and Hans-Dieter Ehrich", TITLE ="{Algebraic and Operational Semantics of Specifications Allowing Exceptions and Errors}", INSTITUTION="{Universit{\"a}t Dortmund, Abteilung Informatik}", YEAR ="{1982}", type ="{Forschungsbericht}", number ="{140}", abstract="{ The specification of abstract data types requires the possibility to treat exceptions and errors. We present an approach allowing all forms of error handling: error introduction, error propagation and error recovery. The algebraic semantics of our method and a new correctness criterion are given. We also introduce an operational semantics of a subclass of our specifications which coincides with the algebraic semantics.}" } @INPROCEEDINGS{Gogolla:1982:GITheoryConference, AUTHOR ="Martin Gogolla and Klaus Drosten and Udo Lipeck and Hans-Dieter Ehrich", TITLE ="{Algebraic and Operational Semantics of Exceptions and Errors}", BOOKTITLE ="{Proc. 6th GI Conf. Theoretical Computer Science}", YEAR ="{1982}", editor ="Armin B. Cremers and Hans-Peter Kriegel", pages ="{141--151}", publisher ="{Springer, Berlin, LNCS~145}", isbn ="ISBN~3-540-11973-6", abstract="{ The specification of abstract data types requires the possibility to treat exceptions and errors. We present an approach allowing all forms of error handling: error introduction, error propagation and error recovery. The algebraic semantics of our method and a new correctness criterion are given. We also introduce an operational semantics of a subclass of our specifications which coincides with the algebraic semantics.}" } @TECHREPORT{Drosten:1982:ReportDortmund144, AUTHOR ="Klaus Drosten and Martin Gogolla and Hans-Dieter Ehrich and Udo Lipeck", TITLE ="{A Hierarchical Approach to an Operational Semantics for Conditional Algebraic Specifications}", INSTITUTION="{Universit{\"a}t Dortmund, Abteilung Informatik}", YEAR ="{1982}", type ="{Forschungsbericht}", number ="{144}", abstract="{ For the specification of abstract data types, it is most convenient in many cases not only to have pure equations, but conditional ones. We present a hierarchical approach where conditions have to be evaluated on underlying levels. An operational semantics is obtained via term rewriting systems. In order to guarantee its well-definedness, we provide sufficient syntactical criteria for the Church-Rosser property. Moreover, these criteria are sufficient for the termination of the full substitution reduction strategy, as well.}" } @INPROCEEDINGS{Gogolla:1983:WADT, AUTHOR ="Martin Gogolla", TITLE ="{Algebraic Specification of Subsorts}", BOOKTITLE ="{Abstracts 2nd Int. Workshop Abstract Data Types~(WADT'83)}", YEAR ="{1983}", editor ="Manfred Broy and Martin Wirsing", publisher ="{Universit{\"a}t Passau, Informatik-Bericht}", abstract="{ A method for the algebraic specification of subsorts and overloaded operators is presented. In this approach algebras are described by equations and declarations. A declaration is a construct, which assures that an expression has a certain type. It is shown that every specification consisting of equations and declarations has an initial model. Furthermore it is proved that declarations can be expressed only by equations using hidden sorts and functions. An as application it is shown how errors and exceptions in abstract data types can be treated by using declarations. For every sort an ok subsort representing the non error elements is introduced and by the use of declarations the functions are divided into those which may introduce errors and those which return ok values when applied to such ones. By this, error introduction and error propagation as well as error recovery is possible.}" } @ARTICLE{Gogolla:1983:EATCSBulletin, AUTHOR ="Martin Gogolla and Hans-Dieter Ehrich", TITLE ="{Algebraic Specifications with Subsorts Using Declarations}", JOURNAL="{Bulletin of the EATCS}", YEAR ="{1983}", volume ="{21}", pages ="{31--38}", isbn ="ISSN~0252~9742", abstract="{ Conventional algebraic specifications describe data types some times only implicit with hidden sorts and functions. A more powerful and elegant technique can be achived by putting more structure into the specification. Our approach distinguishes between basis sorts and subsorts. The subsorts, whose carriers are included in the basis sort carriers, are described by declarations, i.e. a list of terms possibly with variables of basis as well as subsorts. We study the initial algebra semantics of our specifications, which include declarations and equations.}" } @TECHREPORT{Gogolla:1983:ReportDortmund169, AUTHOR ="Martin Gogolla", TITLE ="{Algebraic Specifications with Partially Ordered Sorts and Declarations}", INSTITUTION="{Universit{\"a}t Dortmund, Abteilung Informatik}", YEAR ="{1983}", type ="{Forschungsbericht}", number ="{169}", abstract="{ Conventional algebraic specification techniques cannot express relationships between sorts formally. The approach presented here puts more structure into the specification by allowing a partial ordering on the set of sorts to describe that one sort is a subsort of another sort. This concept implies that one function can occur more than one time in the signature with different domains and codomains. Apart from equations our specifications allow declarations to type a term of a certain sort to a subsort of the given one. The initial algebra semantics of our specifications with a partial ordering on the set of sorts are studied.}" } @INPROCEEDINGS{Gogolla:1984:CAAP, AUTHOR ="Martin Gogolla", TITLE ="{Partially Ordered Sorts in Algebraic Specifications}", BOOKTITLE ="{Proc. 9th Int. Colloquium Trees in Algebra and Programming~(CAAP'84)}", YEAR ="{1984}", editor ="Bruno Courcelle", pages ="{139--153}", publisher ="{Cambridge University Press, Cambridge}", isbn ="ISBN~0-521-26750-1", abstract="{ Conventional algebraic specification techniques cannot express relationships between sorts formally. The approach presented here puts more structure into the specification by allowing a partial ordering on the set of sorts to describe that one sort is a subsort of another sort. This concept implies that one function can occur more than one time in the signature with different domains and codomains. The initial algebra semantics of our specifications with a partial ordering on the set of sorts are studied.}" } @ARTICLE{Gogolla:1984:TCS, AUTHOR ="Martin Gogolla and Klaus Drosten and Udo Lipeck and Hans-Dieter Ehrich", TITLE ="{Algebraic and Operational Semantics of Specifications Allowing Exceptions and Errors}", JOURNAL="{Theoretical Computer Science}", YEAR ="{1984}", volume ="{34}", pages ="{289--313}", isbn ="ISBN~0304-3975", abstract="{ The specification of abstract data types requires the possibility to treat exceptions and errors. We present an approach allowing all forms of error handling: error introduction, error propagation and error recovery. The algebraic semantics of our method and a new correctness criterion are given. We also introduce an operational semantics of a subclass of our specifications which coincides with the algebraic semantics.}" } @INPROCEEDINGS{Gogolla:1984:WADTAbstracts, AUTHOR ="Martin Gogolla", TITLE ="{A Final Algebra Semantics for Errors and Exceptions}", BOOKTITLE ="{Abstracts 3rd Int. Workshop Abstract Data Types~(WADT'84)}", YEAR ="{1984}", editor ="Hans-J{\"o}rg Kreowski and Anne Wilharm", publisher ="{Universit{\"a}t Bremen, Informatik-Bericht~9/84}", isbn ="ISSN~0722-8996", abstract ="{ Algebraic specifications allowing equations and inequations are studied. A characterisation of the existence of models and initial algebras as well as a criterion for the existence of final algebras for such specifications are given. As an application it is shown, how the result can be applied to yield maximal error propagation preserving error recovery in abstract data types.}" } @INPROCEEDINGS{Ehrich:1984:VLDB, AUTHOR ="Hans-Dieter Ehrich and Udo Walter Lipeck and Martin Gogolla", TITLE ="{Specification, Semantics and Enforcement of Dynamic Database Constraints}", BOOKTITLE ="{Proc. 10th Int. Conf. Very Large Data Bases~(VLDB'84)}", YEAR ="{1984}", editor ="Umeshwar Dayal and Gunter Schlageter and Lim Huat Seng", pages ="{310--318}", isbn ="ISBN~0-934613-16-8", publisher ="{Morgan Kaufmann, San Mateo}", abstract ="{ In order to specify dynamic constraints, we present a simplified version of temporal logic based on the temporal quantifiers ``always'' and ``sometime'' as well as their bounded versions ``always..until'' and ``sometime..before''. We show that, in most practical cases, the bounded temporal quantifiers can be expressed by appropriate formulas with unbounded temporal quantifiers. We then use special kinds of temporal formulas as a language to specify dynamic constraints. The problem of enforcing such constraints is then reduced to the problem of enforcing dynamically changing sets of two kinds of static constraints, called universal and existential constraints. While universal constraints can be enforced strictly in principle, violation of existential constraints cannot be detected in each case at the earliest moment. We give a sufficient criterion for detecting violation of existential constraints.}" } @TECHREPORT{Gogolla:1985:ReportBraunschweig, AUTHOR ="Martin Gogolla", TITLE ="{A Final Algebra Semantics for Errors and Exceptions}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1985}", type ="{Informatik-Bericht}", number ="{85-06}", abstract="{ Algebraic specifications allowing equations and inequations are studied. A characterisation of the existence of models and initial algebras as well as a criterion for the existence of final algebras for such specifications are given. As an application it is shown, how the result can be applied to yield maximal error propagation preserving error recovery in abstract data types.}" } @INPROCEEDINGS{Gogolla:1985:WADT, AUTHOR ="Martin Gogolla", TITLE ="{A Final Algebra Semantics for Errors and Exceptions}", BOOKTITLE ="{Proc. 3rd Int. Workshop Abstract Data Types~(WADT'84)}", YEAR ="{1985}", editor ="Hans-J{\"o}rg Kreowski", pages ="{89--103}", publisher ="{Springer Berlin, Informatik Fachberichte~116}", isbn ="ISBN~3-540-16077-9", abstract ="{ Algebraic specifications allowing equations and inequations are studied. A characterisation of the existence of models and initial algebras as well as a criterion for the existence of final algebras for such specifications are given. As an application it is shown, how the result can be applied to yield maximal error propagation preserving error recovery in abstract data types.}" } @INPROCEEDINGS{Lipeck:1985:TFAIS, AUTHOR ="Udo Walter Lipeck and Hans-Dieter Ehrich and Martin Gogolla", TITLE ="{Specifying Admissibility of Dynamic Database Behaviour Using Temporal Logic}", BOOKTITLE ="{Proc. IFIP Working Conf. Theoretical and Formal Aspects of Information Systems~(TFAIS'85)}", YEAR ="{1985}", editor ="Amilcar Sernadas and Janis Bubenko and Antoni Olive", pages ="145--157", publisher ="{North Holland, Amsterdam}", isbn ="ISBN~0-444-87706-1", abstract ="{ This work uses temporal logic as a calculus for expressing integrity constraints that specify admissibility of dynamic database behaviour. Formulas are interpreted in state sequences representing dynamic behaviour. Our approach incorporates temporal quantifications by ``always'' and ``sometime'', and quantifiers bounded by intervals in state sequences. Moreover, dynamically changing domains of database values are considered. We then use special kinds of formulas as a language for dynamic constraints and give some hints how to specify in typical situations. For such formulas, a frame for monitoring constraints during runtime of a database is discussed which allows to characterize admissibility operationally.}" } @PHDTHESIS{Gogolla:1986:PhD, AUTHOR ="Martin Gogolla", TITLE ="{{\"U}ber Partiell Geordnete Sortenmengen und deren Anwendung zur Fehlerbehandlung in Abstrakten Datentypen}", SCHOOL ="{Technische Universit{\"a}t Braunschweig, Naturwissenschaftliche Fakult{\"a}t}", YEAR ="{1986}", note ="{Mainly material from the CAAP'84, TCS'84, WADT'84 and TAPSOFT'87 papers}", abstract ="{ Algebraische Spezifikationen von Datentypen werden um Ausdrucksmittel zur Darstellung von Halbordnungen auf den Tr{\"a}gern erweitert. Dies erm{\"o}glicht insbesondere die Behandlung von Unter- und Obersorten. Neben Gleichungen werden auch Deklarationen in Spezifikationen zugelassen, die es gestatten, einem Term eine neue Sorte zuzuweisen. Als Semantik ergibt sich stets eine initiale Algebra. Auf dieser Basis werden verschiedene Methoden zur Behandlung von Fehlern und Ausnahmen in abstrakten Datentypen vorgestellt, und ein Vorschlag zu deren Parametrisierung wird diskutiert.}", abstract2 ="{ Algebraic specifications of data types are extended to treat partially ordered sorts. This permits the formal specification of sub- and supersorts. Apart from equations we allow declarations assigning new types to terms and study the initial algebra semantics of our specifications. On this basis we introduce different methods to treat errors and exceptions in abstract data types and discuss a proposal to parametrize them.}" } @INPROCEEDINGS{Ehrich:1986:DS2, AUTHOR ="Hans-Dieter Ehrich and Klaus Drosten and Martin Gogolla", TITLE ="{Towards an Algebraic Semantics for Database Specification}", BOOKTITLE ="{Proc. 2nd IFIP 2.6 Working Conf. Database Semantics~(DS-2'86)}", YEAR ="{1988}", editor ="Robert A. Meersman and Amilcar C. Sernadas", pages ="119--135", publisher ="{North Holland, Amsterdam}", isbn ="ISBN~0444-70528-7", abstract ="{ In the framework of a modal-algebraic approach to database semantics, the specification of abstract object types on the basis of abstract data types is studied. As a semantic framework for determining admissible states and state sequences, a standard universe of ``possible objects'' and their interrelationships has to be associated with a schema specification. This paper gives a construction of such a standard universe from a given key system including certain constraints. There is also an abstract algebraic characterisation of the universe (up to isomorphism) in the terms of final algebras. Within this framework, a general definition of admissible states and state sequences as the semantics of a schema specification is discussed briefly.}" } @PROCEEDINGS{Ehrich:1986:WADT, TITLE ="{Abstracts 4th Int. Workshop Abstract Data Types~(WADT'86)}", YEAR ="{1986}", editor ="Hans-Dieter Ehrich and Klaus Drosten and Martin Gogolla and Udo Walter Lipeck", publisher ="{Technische Universit{\"a}t Braunschweig, Informatik-Bericht Nr.~86-09}", abstract ="{ Here are the abstracts of talks presented at the 4th Workshop on Specification of Abstract Data Types which was held at Burg Warberg near Braunschweig, May 20-23, 1986. About 70 participants attended the workshop, more than ever before in this series of workshops, starting in Langscheid 1982 and going on in Passau 1983 and in Bremen 1984. We all look forward to the next meeting in Edinburgh which is scheduled to take place in fall 1987 and will be organized by Don Sannella.}" } @INPROCEEDINGS{Gogolla:1986:WADT, AUTHOR ="Martin Gogolla", TITLE ="{Exception Handling and Subsorts}", BOOKTITLE ="{Abstracts 4th Int. Workshop Abstract Data Types~(WADT'86)}", YEAR ="{1986}", editor ="Hans-Dieter Ehrich and Klaus Drosten and Martin Gogolla and Udo Walter Lipeck", publisher ="{Technische Universit{\"a}t Braunschweig, Informatik-Bericht Nr.~86-09}", abstract ="{ Usual algebraic specification techniques can be extended to treat partially ordered sorts. This allows the introduction of sub- and supersorts as well as overloaded operators, while pleasant features of the equational specification method (e.g. existence of initial algebras and equivalence of algebraic and operational semantics) are preserved. Partially ordered sorts can also be used as a basis for exception and error handling. We discuss three different, but closey related methods: (1) Ok-subsorts, (2) error-subsorts, and (3) disjoint ok- and error-subsorts. In particular, the three approaches are considered with respect to error introduction, error propagation and error recovery.}" } @INPROCEEDINGS{Gogolla:1987:TAPSOFT, AUTHOR ="Martin Gogolla", TITLE ="{On Parametric Algebraic Specifications with Clean Error Handling}", BOOKTITLE ="{Proc. 2nd Int. Joint Conf. Theory and Practice of Software Development~(TAPSOFT'87)}", YEAR ="{1987}", editor ="Hartmut Ehrig and Robert Kowalski and Giorgio Levi", pages ="{81--95}", publisher ="{Springer, Berlin, LNCS~249}", isbn ="ISBN~3-540-17660-8", abstract ="{ Usual algebraic specification techniques can be extended to treat partially ordered sorts. This allows the introduction of sub- and supersorts as well as overloaded operators, while pleasant features of the equational specification method (e.g. existence of initial algebras and equivalence of algebraic and operational semantics) are preserved. On this basis error and exception handling is studied. For each sort an ok and an error subsort is introduced and clean algebras (i.e. algebras which are ok-error-consistent and ok-error-complete) are considered. This new approach allows to prove an extension lemma for persistent parametric specifications which permit error handling.}" } @TECHREPORT{Hohenstein:1988:ReportBraunschweig, AUTHOR ="Uwe Hohenstein and Martin Gogolla", TITLE ="{Towards a Semantic View of an Extended Entity-Relationship Model}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1988}", type ="{Informatik-Bericht}", number ="{88-02}", abstract ="{ This paper introduces an extended ER model concentrating nearly all concepts of known so-called semantic data models to a few syntactical constructs. Moreover, we provide our extended ER model with a formal mathematical semantics. On this basis a well-founded calculus is developed taking into account data operations on arbitrary user-defined data types and aggregate functions. We pay special attention to arithmetic operations as well as multivalued terms allowing nested queries in a uniform and consistent manner. We prove our calculus only allows the formulation of safe terms and queries yielding a finite result, and to be (at least) as expressive as the relational calculus.}" } @INPROCEEDINGS{Hohenstein:1988:ER, AUTHOR ="Uwe Hohenstein and Martin Gogolla", TITLE ="{A Calculus for an Extended Entity-Relationship Model Incorporating Arbitrary Data Operations and Aggregate Functions}", BOOKTITLE ="{Proc. 7th Int. Conf. Entity-Relationship Approach~(ER'88)}", YEAR ="{1988}", editor ="Carlo Battini", pages ="{129--148}", publisher ="{North-Holland, Amsterdam}", isbn ="ISBN~0-444-87453-4", abstract ="{ We propose a semantically well-founded Entity-Relationship calculus that takes into account data operations (especially arithmetic operations) on arbitrary defineable data types and aggregate functions, as well as multivalued terms allowing nested queries in a uniform and consistent manner. We define our calculus in a way that only allows the formulation of safe terms and queries (yielding a finite result) and that it is (at least) as powerful as the relational calculi. The calculus is based upon an extended ER model concentrating nearly all concepts of known so-called semantic data models to a few syntactical constructs. Moreover, we provide our extended ER model with a formal semantics, since otherwise the semantics of the calculus cannot be defined mathematically precise.}" } @INPROCEEDINGS{Gogolla:1989:TAPSOFT, AUTHOR ="Martin Gogolla", TITLE ="{Algebraization and Integrity Constraints for an Extended Entity-Relationship Approach}", BOOKTITLE ="{Proc. 3rd Int. Joint Conf. Theory and Practice of Software Development~(TAPSOFT'89)}", YEAR ="{1989}", editor ="Josep Diaz and Fernando Orejas", pages ="{259--274}", publisher ="{Springer Berlin, LNCS~351}", isbn ="ISBN~3-540-50939-9", abstract ="{ An extended Entity-Relationship model concentrating nearly all concepts of known ``semantic'' data models and especially allowing arbitrary user defined data types is introduced. The semantics of the model is described purely in algebraic terms mainly based on the notions of signature, algebra and extension. On this basis a calculus making intensive use of abstract data types is defined and employed for the formulation of typical integrity constaints like functional restrictions and key specifications.}" } @INCOLLECTION{Gogolla:1989:ReportBremen, AUTHOR ="Martin Gogolla and Hans-Dieter Ehrich", TITLE ="{Contributions to ``COMPASS - A Comprehensive Algebraic Approach to System Specification and Development''}", BOOKTITLE="{COMPASS - A Comprehensive Algebraic Approach to System Specification and Development}", PUBLISHER="{Universit{\"a}t Bremen, Informatik-Bericht~6/89}", YEAR ="{1989}", editor ="Bernd Krieg-Br{\"u}ckner", isbn ="ISSN~0722-8996", abstract ="{ COMPASS is funded as a Basic Research Workong Group under the ESPRIT Programme of the European Communities. This document contains those three chapters of the original proposal that we believe to be of potential interest to a wider audience. The first chapter states the general objectives of the cooperation in the Working Group. The second chapter gives a summary of the State of the Art for and of our own work as we saw it in June 1988. Thus it is in many ways incomplete with respect to the work of others and does not claim full coverage. We believe, however, that it provides an overview that might be of interest for other researchers in the area of Formal Methods in Computing Science. The third chapter lists the references to work mentioned in the previous chapter. Again, it is by no means complete. Overall, chapter II and III can be regarded as a first approximation of an annotated bibliography of the area of algebraic specification.}" } @PROCEEDINGS{Ehrich:1989:ReportBraunschweig, TITLE ="{Abstracts Workshop Grundlagen von Datenbanken~(GvD'89)}", YEAR ="{1989}", editor ="Hans-Dieter Ehrich and Gregor Engels and Martin Gogolla and Gunter Saake", publisher ="{Technische Universit{\"a}t Braunschweig, Informatik-Bericht Nr.~89-02}", abstract ="{ Der vorliegende Bericht fa\ss{}t die Kurzfassungen der Vortr{\"a}ge zusammen, die f{\"u}r den Workshop Grundlagen von Datenbanken (16.-19.5.89 im Herrenhaus Volkse) angemeldet wurden. Der Workshop hat das Anliegen, die Kommunikation zwischen den deutschsprachigen Arbeitsgruppen zu f{\"o}rdern, die um Bereich der theoretischen, konzeptionellen und methodologischen Grundlagen von Daten- und Wissensbanken arbeiten. Insbesondere den j{\"u}ngeren Nachwuchswissenschaftlern soll der Workshop Gelegenheit bieten, in zwangloser Umgebung Ideen, Ans{\"a}tze und Ergebnisse auszutauschen und zu diskutieren. Die Vielfalt der Anmeldungen zeigt, da\ss{} f{\"u}r Workshops dieser Art - und dieser Thematik - ein gro\ss{}er Bedarf besteht.}" } @INPROCEEDINGS{Gogolla:1989:GvD, AUTHOR ="Martin Gogolla", TITLE ="{Zur {\"U}bersetzung eines ER-Kalk{\"u}ls nach Prolog}", BOOKTITLE ="{Abstracts Workshop Grundlagen von Datenbanken~(GvD'89)}", YEAR ="{1989}", editor ="Hans-Dieter Ehrich and Gregor Engels and Martin Gogolla and Gunter Saake", publisher ="{Technische Universit{\"a}t Braunschweig, Informatik-Bericht Nr.~89-02}", abstract ="{ Auf der Basis eines erweiterten ER Modells werden sowohl Schemata als auch die zugeh{\"o}rigen Datenbanzust{\"a}nde mittels Prolog-Fakten dargestellt. Es wird ein Verfahren angegeben, das es gestattet, Terme eines auf dem erweiterten ER Modell aufbauenden Kalk{\"u}ls in {\"a}quivalente Prolog-Pr{\"a}dikate zu {\"u}bersetzen. Mit Hilfe dieser Terme bzw. der entsprechenden Prolog-Pr{\"a}dikate lassen sich einerseits Anfragen bzgl. des gegebenen Datenbankzustands formulieren und auswerten. Andererseits dienen diese Terme bzw. die {\"a}quivalenten Prolog-Pr{\"a}dikate auch zur {\"U}berpr{\"u}fung (statischer) Integrit{\"a}tsbedingengen im repr{\"a}sentierten Zustand.}" } @BOOK{Ehrich:1989:Teubner, AUTHOR ="Hans-Dieter Ehrich and Martin Gogolla and Udo Walter Lipeck", TITLE ="{Algebraische Spezifikation Abstrakter Datentypen - Eine Einf{\"u}hrung in die Theorie}", PUBLISHER="{Teubner, Stuttgart}", YEAR ="{1989}", series ="{Leitf{\"a}den und Monographien der Informatik}", abstract ="{ Dieses Buch ist aus der {\"U}berarbeitung und Erweiterung von Notizen zu Vorlesungen entstanden, die seit 1977 zun{\"a}chst vom ersten Autor an der Universit{\"a}t Dortmund, seit 1982 dann von allen drei Autoren in wechselnder Folge an der Technischen Universit{\"a}t Braunschweig gehalten wurden. Der Schwerpunkt des Buches liegt bei den theoretischen Grundlagen, jedoch haben die M{\"o}glichkeiten und Grenzen praktischer Anwendung die Auswahl und die Gestaltung des Stoffes stark beeinflu\ss{}t. Das Buch richtet sich vornehmlich an Informatiker, die sich mit Grundlagen des Software-Entwurfs auseinandersetzen wollen, und an Mathematiker, die sich f{\"u}r Anwendungen der universellen Algebra und der Logik in der Informatik interessieren.}" } @ARTICLE{Gogolla:1990:EATCSBulletin, AUTHOR ="Martin Gogolla", TITLE ="{A Note on the Translation of SQL to Tuple Calculus}", JOURNAL="{Bulletin of the EATCS}", YEAR ="{1990}", volume ="{40}", pages ="{231--236}", isbn ="ISSN~0252~9742", abstract="{ This note presents a translation of a subset of the relational query language SQL into the well known tuple calculus. Roughly speaking, tuple calculus corresponds to first order predicate calculus. The SQL subset is relationally complete and represents a ``relational core'' of the language. Nevertheless, our translation is simple and elegant. Therefore it is especially well suited as a beginners course into the principles of a formal definition of SQL.}" } @ARTICLE{Gogolla:1990:ACMSIGMODRecord, AUTHOR ="Martin Gogolla", TITLE ="{A Note on the Translation of SQL to Tuple Calculus}", JOURNAL="{ACM SIGMOD Record}", YEAR ="{1990}", volume ="{19}", number ="{1}", pages ="{18--22}", isbn ="ISSN~0163-5808", abstract="{ This note presents a translation of a subset of the relational query language SQL into the well known tuple calculus. Roughly speaking, tuple calculus corresponds to first order predicate calculus. The SQL subset is relationally complete and represents a ``relational core'' of the language. Nevertheless, our translation is simple and elegant. Therefore it is especially well suited as a beginners course into the principles of a formal definition of SQL.}" } @TECHREPORT{Karge:1990:ReportBraunschweig, AUTHOR ="Ulrich Karge and Martin Gogolla", TITLE ="{Formal Semantics of SQL Queries}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1990}", type ="{Informatik-Bericht}", number ="{90-02}", abstract ="{ A formal semantics of the relational query language SQL (Structured Query Language) is presented by translating SQL into an extended relational calculus. This calculus allows the handling of grouping and aggregation as well as null vallues, and therefore special emphasis is laid on the correct translation of grouping and aggregation of SQL. The translation of an SQL query is performed in eight steps. Some steps can be omitted for most of the queries. Making use of the presented translation, it is possible to prove properties of SQL, e.g. subqueries which are added with IN, ALL, or EXISTS can be replaced equivalently by subqueries using the aggregation function COUNT.}" } @INPROCEEDINGS{Gogolla:1990:GvD, AUTHOR ="Martin Gogolla and Ulrich Karge", TITLE ="{Zur formalen Semantik von SQL}", BOOKTITLE ="{Kurzfassungen 2. Workshop Grundlagen von Datenbanken~(GvD'90)}", YEAR ="{1990}", editor ="Udo Walter Lipeck and Stefan Bra\ss{} and Gunter Saake", pages ="{27--29}", publisher ="{Technische Universit{\"a}t Braunschweig, Informatik-Bericht Nr.~90-02}", abstract ="{ Es wird ein Vorschlag zur Definition der formalen Semantik von SQL auf der Grundlage eines erweiterten Entity-Relationship-Kalk{\"u}ls diskutiert. Dieser zugrunde liegende Kalk{\"u}l gestattet insbesondere eine semantisch wohl-definierte Verwendung von Aggregierungsfunktionen auf der Grundlage von Multimengen. Damit ist es m{\"o}glich, sowohl die SQL Gruppierungsm{\"o}glichkeiten mittels GROUP BY als auch die (zumindest teilweise) hierauf basierenden SQL Aggregierungen MAX, MIN, AVG, COUNT und SUM pr{\"a}zise zu erkl{\"a}ren. Auf dieser Grundlage k{\"o}nnen so Aussagen u.a. {\"u}ber die {\"A}quivalenz von Anfragen und somit {\"u}ber beweisbare Eigenschaften der Sprache gemacht werden. Auf diesem Weg wird dann auch gezeigt, da\ss{} Unteranfragen, die mittels IN, ALL, ANY oder EXISTS gebildet werden, sich durch ein einziges Konstrukt, n{\"a}mlich COUNT ausdr{\"u}cken lassen.}" } @TECHREPORT{Gogolla:1990:SkriptBraunschweig, AUTHOR ="Martin Gogolla", TITLE ="{Datalog - Eine deduktive Datenbanksprache}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1990}", type ="{Informatik-Skript}", number ="{25}", abstract ="{ Die vorliegenden Notizen sind \"Uberarbeitungen der Folien, die f\"ur eine Vorlesung verwendet wurden. Stoffauswahl und Detailierungsgrad waren wesentlich von dem Umstand bestimmt, da{\ss} eine zweist\"undige Veranstaltung in einem Sommersemester mit 12 Wochen gehalten wurde. Die Struktur der Vorlesung lehnt sich an einen \"Ubersichtsartikel von Ceri, Gottlob und Tanca an. Zus\"atzliche Definitionen, S\"atze, Verfahren und Beispiele stammen aus der angegebenen Literatur. Andere Beispiele wurden in der Veranstaltung entwickelt. Die H\"orer der Vorlesung haben durch kritische Fragen und Bemerkungen zur Verbesserung des Materials beigetragen.}" } @TECHREPORT{Meyer:1990:ReportBraunschweig, AUTHOR ="Bernd Meyer and Gerhard D. Westerman and Martin Gogolla", TITLE ="{QUEER - A Prolog Based Prototype for an Extended ER Approach}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1990}", type ="{Informatik-Bericht}", number ="{90-03}", abstract ="{ The combination of logic programming and databases has been given broad attention in recent years. However, mainly the connections between the relational data model and logic programming have been investigated. The application of logic programming languages as a basis for information systems founded on more complex, i.e. conceptual data models has received comparatively less attention. With the system QUEER, we introduce the prototype of a PROLOG-based information system which directly supports an extended Entity-Relationship model on its front-end and uses a semantically well-founded query and manipulation language based on an Entity-Relationship calculus. The system basically consists of a set of compilers written in PROLOG which translate data specifications, schema definitions, queries, and data-manipulation statements into PROLOG programs.}" } @TECHREPORT{Engels:1990:ReportBraunschweig, AUTHOR ="Gregor Engels and Martin Gogolla and Uwe Hohenstein and Klaus H{\"u}lsmann and Perdita L{\"o}hr-Richter and Gunter Saake and Hans-Dieter Ehrich", TITLE ="{Conceptual Modelling of Database Applications Using an Extended ER Model}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1990}", type ="{Informatik-Bericht}", number ="{90-05}", abstract ="{ In this paper, we motivate and present a data model for conceptual design of structural and behavioural aspects of databases. We follow an object centered design paradigm in the spirit of semantic data models. The specification of structural aspects is divided into modelling of object structures and modelling of data types used for describing object properties. The specification of object structures is based on an Extended Entity-Relationship (EER) model. The specification of behavioural aspects is divided into the modelling of admissible database state evolutions by means of temporal integrity constraints and the formulation of database (trans)actions. The central link for integrating these design components is a descriptive logic-based query language for the EER model. The logic part of this language is the basis for static constraints and descriptive action specifications by means of pre- and postconditions.}" } @TECHREPORT{Classen:1991:ReportBerlin, AUTHOR ="Ingo Cla\ss{}en and Martin Gogolla", TITLE ="{Towards a Conceptual Model for the Environment of the Algebraic Specification Language ACT ONE}", INSTITUTION="{Technische Universit{\"a}t Berlin}", YEAR ="{1991}", type ="{Forschungsbericht}", number ="{91/11}", abstract ="{ The paper defines a conceptual model for the algebraic specification language ACT ONE and its accompanying specification environment. But the approach chosen is quite general and can be employed for other specification languages as well. The definition of the database schema including integrity constraints is done by means of an expressive and semantically well-founded extended Entity-Relationship model and a respective calculus. The basic idea is to start with the context free grammar of ACT ONE and to introduce entity types for non-terminal symbols. Productions are modelled by a type construction and appropriate components. Context sensitive conditions are translated into integrity constraints formulated in the calculus. This approach especially allows to describe various degrees of incompleteness of ACT ONE types, for instance whether an ACT ONE type has already been checked syntactically or whether the flat equivalent of the type is available.}" } @INCOLLECTION{Gogolla:1991:LNCS501, AUTHOR ="Martin Gogolla and Hans-Dieter Ehrich", TITLE ="{Contributions to ``COMPASS - A Comprehensive Algebraic Approach to System Specification and Development''}", BOOKTITLE="{COMPASS - A Comprehensive Algebraic Approach to System Specification and Development}", PUBLISHER="{Springer, Berlin, LNCS~501}", YEAR ="{1991}", editor ="Michel Bidoit and Hans-J{\"o}rg Kreowski and Pierre Lescanne and Fernando Orejas and Don Sannella", isbn ="ISBN~3-540-54060-1", abstract ="{ This volume arose out of the work of the COMPASS Basic Research Working Group, funded by the European Community under the Basic Research Action programme, ref. no. 3264. The name COMPASS stands for ``a COMPrehensive Algebraic approach to System Specification and development''. An early version of this document was included in the original COMPASS project proposal as a review of the state of the art. The current version is the result of suggestions for improvements from the participants in the COMPASS project, assembled and edited into a more or less coherent form by five editors. Since the COMPASS working group includes most of the leading European experts in algebraic specification, the result should be a relatively comprehensive overview of the main work in the field. In spite of its deficiencies, we hope that it nevertheless represents a useful snapshot of the current state of the art.}" } @ARTICLE{Gogolla:1991:ACMTODS, AUTHOR ="Martin Gogolla and Uwe Hohenstein", TITLE ="{Towards a Semantic View of an Extended Entity-Relationship Model}", JOURNAL="{ACM Transactions on Database Systems}", YEAR ="{1991}", volume ="{16}", number ="{3}", pages ="{369--416}", isbn ="ISSN~0362-5915", abstract ="{ This paper introduces an extended ER model concentrating nearly all concepts of known so-called semantic data models to a few syntactical constructs. Moreover, we provide our extended ER model with a formal mathematical semantics. On this basis a well-founded calculus is developed taking into account data operations on arbitrary user-defined data types and aggregate functions. We pay special attention to arithmetic operations as well as multivalued terms allowing nested queries in a uniform and consistent manner. We prove our calculus only allows the formulation of safe terms and queries yielding a finite result, and to be (at least) as expressive as the relational calculi.}" } @INPROCEEDINGS{Gogolla:1991:ER, AUTHOR ="Martin Gogolla and Bernd Meyer and Gerhard D. Westerman", TITLE ="{Drafting Extended Entity-Relationship Schemas with QUEER}", BOOKTITLE ="{Proc. 10th Int. Conf. Entity-Relationship Approach~(ER'91)}", YEAR ="{1991}", editor ="Toby Teorey", pages ="{561--585}", publisher ="{ER Institute, San Mateo}", abstract ="{ The system QUEER is a prototype of an information system design tool which directly supports an extended Entity-Relationship model on its front-end and uses a semantically well-founded query and manipulation language based on an Entity-Relationship calculus. The system basically consists of a set of compilers written in PROLOG which translate data specifications, schema definitions, queries, integrity constraints, and data-manipulation statements into PROLOG programs. All features mentioned are implemented in form and extent as described here.}" } @ARTICLE{Conrad:1992:ACMSIGMODRecord, AUTHOR ="Stefan Conrad and Martin Gogolla", TITLE ="{An Annotated Bibliography on Object-Orientation and Deduction}", JOURNAL ="{ACM SIGMOD Record}", YEAR ="{1992}", volume ="{21}", number ="{1}", pages ="{123--132}", isbn ="ISSN~0163-5808", abstract="{ This note tries to briefly survey research activities and results on the integration of object-oriented concepts and deductive database languages.}" } @INPROCEEDINGS{Ehrich:1991:WADT, AUTHOR ="Hans-Dieter Ehrich and Martin Gogolla and Amilcar Sernadas", TITLE ="{Objects and Their Specification}", BOOKTITLE ="{Proc. 8th Int. Workshop Abstract Data Types~(WADT'91)}", YEAR ="{1991}", editor ="Michel Bidoit and Christine Choppy", pages ="{40--65}", publisher ="{Springer, Berlin, LNCS~655}", isbn ="ISBN~3-540-56379-2", abstract ="{ Object-oriented concepts and constructions are explained in an informal and language-independent way. Various algebraic approaches for dealing with objects and their specification are examined, ADT-based ones as well as process-based ones. The conclusion is that the process view of objects seems to be more appropriate than the data type view.}" } @ARTICLE{Engels:1992:DKE, AUTHOR ="Gregor Engels and Martin Gogolla and Uwe Hohenstein and Klaus H{\"u}lsmann and Perdita L{\"o}hr-Richter and Gunter Saake and Hans-Dieter Ehrich", TITLE ="{Conceptual Modelling of Database Applications Using an Extended ER Model}", JOURNAL="{Data and Knowledge Engineering}", YEAR ="{1992}", volume ="{9}", number ="{2}", pages ="{157--204}", abstract="{ In this paper, we motivate and present a data model for conceptual design of structural and behavioural aspects of databases. We follow an object centered design paradigm in the spirit of semantic data models. The specification of structural aspects is divided into modelling of object structures and modelling of data types used for describing object properties. The specification of object structures is based on an Extended Entity-Relationship (EER) model. The specification of behavioural aspects is divided into the modelling of admissible database state evolutions by means of temporal integrity constraints and the formulation of database (trans)actions. The central link for integrating these design components is a descriptive logic-based query language for the EER model. The logic part of this language is the basis for static constraints and descriptive action specifications by means of pre- and postconditions.}" } @INPROCEEDINGS{Herzig:1992:ER, AUTHOR ="Rudolf Herzig and Martin Gogolla", TITLE ="{Transforming Conceptual Data Models into an Object Model}", BOOKTITLE ="{Proc. 11th Int. Conf. Entity-Relationship Approach~(ER'92)}", YEAR ="{1992}", editor ="G{\"u}nter Pernul and A Min Tjoa", pages ="{280--298}", publisher ="{Springer, Berlin, LNCS~645}", isbn ="ISBN~3-540-56023-8", abstract ="{ In this paper a conceptually simple structural object model focusing on object types, attributes and ISA relationships is introduced. The model is derived mainly from an extended Entity-Relationship approach, but concepts from other semantic and object-oriented models have influenced its features. It is shown how high-level conceptual data models can be mapped to this model, and to what extent the object model subsumes classical modeling paradigms.}" } @INCOLLECTION{Wirsing:1992:ReportMuenchen, AUTHOR ="Martin Gogolla", TITLE ="{Contributions to ``A Framework for Software Development in KORSO''}", BOOKTITLE="{A Framework for Software Development in KORSO}", PUBLISHER="{Ludwig-Maximilians-Universit{\"a}t M{\"u}nchen, Institut f{\"u}r Informatik, Bericht 9205}", YEAR ="{1992}", editor ="Martin Wirsing", abstract ="{ This paper reports on the results of the first meeting of the KORSO methods group, held in Munich, January 1992. It presents an outline of a framework for a software development methodology in KORSO. The framework is based on a generic algebraic-axiomatic approach to software development. Goals and requirements for KORSO developments are described. The roles of correctness and verification are discussed.}" } @TECHREPORT{Conrad:1992:ReportBraunschweig, AUTHOR ="Stefan Conrad and Martin Gogolla and Rudolf Herzig", TITLE ="{TROLL light - A Core Language for Specifying Objects}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1992}", type ="{Informatik-Bericht}", number ="{92-02}", abstract ="{ TROLL light is a language for conceptual modeling of information systems. It is designed to describe the Universe of Discourse (UoD) as a system of concurrently existing and interacting objects. TROLL light objects have observable properties modeled by attributes, and the behavior of objects is described by events. Possible object observations may be restricted by constraints, whereas event occurrences may be restricted to specified life cycles. TROLL light objects are organized in an object hierarchy established by subobject relationships. Communication among objects is supported by event calling. Apart from introducing the various possibilities for the syntactical description of objects, we aim to describe how the state of an object community may be changed by event occurrences.}" } @TECHREPORT{Gogolla:1992:Habilitation, AUTHOR ="Martin Gogolla", TITLE ="{Fundamentals and Pragmatics of an Entity-Relationship Approach}", INSTITUTION="{Technische Universit{\"a}t Braunschweig, Naturwissenschaftliche Fakult{\"a}t}", YEAR ="{1992}", type ="{Habilitation thesis}", note ="{Submitted November~1992, Accepted May~1993}", abstract="{ This text presents a comprehensive introduction to an extended Entity-Relationship model both on a conceptual and on a formal, mathematical level. In addition to the primitives given by the data model the text introduces a language for the formulation of constraints in order to restrict database states to consistent ones. The same language can be used to query databases. The text also explains an implementation of the approach chosen in the logic programming language PROLOG and discusses in this context the computational power of the proposed calculus. Finally, the extended Entity-Relationship calculus is applied in order to define the meaning of the relational query language SQL.}" } @INPROCEEDINGS{Vlachantonis:1993:CAiSE, AUTHOR ="Nikolaos Vlachantonis and Rudolf Herzig and Martin Gogolla and Grit Denker and Stefan Conrad and Hans-Dieter Ehrich", TITLE ="{Towards Reliable Information Systems: The KORSO Approach}", BOOKTITLE ="{Proc. 5th Int. Conf. Advanced Information Systems Engineering~(CAiSE'93)}", YEAR ="{1993}", editor ="Colette Rolland and Francois Bodart and Corine Cauvet", pages ="{463--483}", publisher ="{Springer, Berlin, LNCS~685}", isbn ="{ISBN~3-540-56777-1}", abstract ="{ Within the compound project KORSO our team is concerned with the research on techniques and methods for the development of reliable information systems on the basis of formal specifications. Our work focuses on the specification language TROLL light which allows to describe the part of the world which is to be modeled as a community of concurrently existing and communicating objects by determining their structure as well as their behavior. Moreover we develop and implement a computer aided specification environment for TROLL light which permits specification animation as well as the proof of properties of specifications.}" } @INPROCEEDINGS{Ehrich:1993:KORSOWorkshop, AUTHOR ="Hans-Dieter Ehrich and Martin Gogolla and Stefan Conrad and Grit Denker and Rudolf Herzig and Nikolaos Vlachantonis", TITLE ="{Entwicklung zuverl{\"a}ssiger Informationssysteme - Stand der Arbeiten im Januar'93}", BOOKTITLE ="{Korrekte Software durch formale Methoden - 4. KORSO-Workshop~(KORSO'93)}", YEAR ="{1993}", editor ="Manfred Broy and Stefan J{\"a}hnichen", pages ="{50--56}", abstract ="{ Innerhalb des KORSO-Projektes befa\ss{}t sich unsere Gruppe damit, die Entwicklung zuverl{\"a}ssiger Informationssysteme auf der Basis formaler Spezifikationen zu unterst{\"u}tzen. Dazu konzentriert sich unsere Arbeit auf die Spezifikationssprache TROLL light, die es erlaubt, Teile der zu modellierenden Welt als eine Gemeinschaft nebeneinander bestehender und miteinander kommunizierender Objekte zu beschreiben. Auf diese Weise bestimmen wir sowohl die Struktur als auch das Verhalten konzeptioneller Objekte. Unsere Spezifikationsumgebung f{\"u}r TROLL light erlaubt die Animation von Spezifikationen ebenso wie das Beweisen von Eigenschaften der Spezifikationen unter Verwendung von Theorembeweisern.}" } @INPROCEEDINGS{Conrad:1993:GIJahrestagung, AUTHOR ="Stefan Conrad and Grit Denker and Martin Gogolla and Rudolf Herzig and Nikolaos Vlachantonis and Hans-Dieter Ehrich", TITLE ="{Zur Entwicklung zuverl{\"a}ssiger Informationssysteme in KORSO}", BOOKTITLE ="{Proc. 23.~GI Jahrestagung~(GI'93) - Informatik - Wirtschaft - Gesellschaft}", YEAR ="{1993}", editor ="H. Reichel", pages ="{464--469}", publisher ="{Springer, Berlin, Informatik Aktuell}", isbn ="{ISBN~3-540-56777-1}", abstract ="{ Innerhalb des KORSO-Projektes verfolgt unsere Gruppe das Ziel, die Entwicklung zuverl{\"a}ssiger Informationssysteme auf der Basis formaler Spezifikationen zu unterst{\"u}tzen. Dazu konzentriert sich unsere Arbeit auf die Spezifikationssprache TROLL light, die es erlaubt, Teile der zu modellierenden Welt als eine Gemeinschaft nebeneinander bestehender und miteinander kommunizierender Objekte zu beschreiben. Auf diese Weise bestimmen wir sowohl die Struktur als auch das Verhalten der konzeptionellen Objekte. Unsere Spezifikationsumgebung f{\"u}r TROLL light erlaubt die Animation von Spezifikationen ebenso wie das Beweisen von Eigenschaften der Spezifikationen unter Verwendung von Theorembeweisern.}" } @INPROCEEDINGS{Gogolla:1993:AMAST, AUTHOR ="Martin Gogolla and Ingo Cla\ss{}en", TITLE ="{An Object-Oriented Design for the ACT ONE Environment}", BOOKTITLE ="{Proc. 3rd Int. Conf. Algebraic Methodology and Software Technology~(AMAST'93)}", YEAR ="{1993}", editor ="Maurice Nivat and Charles Rattray and Theodor Rus and Giuseppe Scollo", pages ="{361--368}", publisher ="{Springer, London, Workshops in Computing}", isbn ="{ISBN~3-540-19852-0}", abstract ="{ We define a conceptual model, i.e., an information system schema, for the well-established algebraic specification language ACT ONE and its accompanying specification environment. This paper gives a formal description of suitable database support for an environment supporting the interactive development of ACT ONE specifications. The object-oriented data model of TROLL light, a language developed recently within the KORSO project, is used to present the design of such an environment and its dynamic behavior. However, the concepts used are general enough to support other specification and even programming languages as well. Therefore, we feel the design of a conceptual schema for ACT ONE is mainly a case study in employing an object-oriented data model for database support of specification or programming languages. It is therefore a proposal for the consolidation of environments for algebraic specification languages.}" } @INPROCEEDINGS{Gogolla:1993:DISCO, AUTHOR ="Martin Gogolla and Stefan Conrad and Rudolf Herzig", TITLE ="{Sketching Concepts and Computational Model of TROLL light}", BOOKTITLE ="{Proc. 3rd Int. Symposium Design and Implementation of Symbolic Computation Systems~(DISCO'93)}", YEAR ="{1993}", editor ="Alfonso Miola", pages ="{17--32}", publisher ="{Springer, Berlin, LNCS~722}", isbn ="ISBN~3-540-57235-X", abstract ="{ The specification language TROLL light is intended to be used for conceptual modeling of information systems. It is designed to describe a system of concurrently existing and interacting objects. We introduces the various language concepts offered by TROLL light. TROLL light objects have observable properties modeled by attributes, and the behavior of objects is described by events. TROLL light objects are organized in an object hierarchy established by sub-object relationships. Communication among objects is supported by event calling. We outlines a simplified computational model for TROLL light. We explain how single states of an object community are constructed. By parallel occurrence of a finite set of events the states of object communities change. The object community itself is regarded as a graph where the nodes are the object community states reachable from an initial state and the edges represent transitions between states.}" } @INCOLLECTION{Gogolla:1993:Dagstuhl62, AUTHOR ="Martin Gogolla", TITLE ="{TROLL light - A Core Language for Specifying Objects}", BOOKTITLE="{Formal Aspects of Object Base Dynamics}", PUBLISHER="{Dagstuhl-Seminar-Report Nr. 62}", YEAR ="{1993}", editor ="Catriel Beeri and Andreas Heuer and Gunter Saake and Susan Urban", isbn ="ISSN~0940-112", abstract ="{ TROLL light is a language for conceptual modeling of information systems. It is designed to describe the Universe of Discourse (UoD) as a system of concurrently existing and interacting objects. As a basis for our language we took the specification language TROLL. However, some details have been added or modified in order to round off TROLL light. This was necessary because we needed a clear and balanced semantic basis for our specification language. In TROLL light classes are understood as composite objects having the class extension as sub-objects. Therefore in contrast to TROLL an extra notion of class is not needed in TROLL light. Over and above that concepts like class attributes, meta-classes, or heterogeneous classes are inherent in TROLL light. Second TROLL light incorporates a query calculus providing a general declarative query facility for object-oriented databases.}" } @INPROCEEDINGS{Gogolla:1993:ER, AUTHOR ="Martin Gogolla and Rudolf Herzig and Stefan Conrad and Grit Denker and Nikolaos Vlachantonis", TITLE ="{Integrating the ER Approach in an OO Environment}", BOOKTITLE ="{Proc. 12th Int. Conf. Entity-Relationship Approach~(ER'93)}", YEAR ="{1993}", editor ="Ramez Elmasri and Vram Kouramajian and Bernhard Thalheim", pages ="{376--389}", publisher ="{Springer, Berlin, LNCS~823}", isbn ="ISBN~3-540-58217-7", abstract ="{ We translate Entity-Relationship (ER) schemas into the object-oriented specification language TROLL light. This language describes the Universe of Discourse (UoD) as a system of concurrently existing and interacting objects, i.e., an object community. Thereby two essential aspects, structure and behavior, are integrated in one formalism. By doing the translation from ER to TROLL light we preserve the visual advantages of the former and receive a formalism through the latter which can be mapped to an adequate object-oriented database system. Proceeding this way we hope our proposal for transforming ER schemas into TROLL light specifications provides a valuable link between structural and dynamic modeling.}" } @INCOLLECTION{Ehrich:1993:InformatikFE, AUTHOR ="Hans-Dieter Ehrich and Martin Gogolla and Stefan Conrad and Grit Denker and Rudolf Herzig and Nikolaos Vlachantonis", TITLE ="{Beitr{\"a}ge zu ``Das BMFT-Verbundprojekt Korrekte Software~(KORSO)''}", BOOKTITLE="{Das BMFT-Verbundprojekt Korrekte Software~(KORSO)}", PUBLISHER="{Informatik - Forschung und Entwicklung, Vol. 8, No. 3}", YEAR ="{1993}", editor ="Manfred Broy and Stefan J{\"a}hnichen", pages ="{160--161}", isbn ="ISSN~0178-3564", abstract ="{ Innerhalb des KORSO-Projektes verfolgt unsere Gruppe das Ziel, die Entwicklung zuverl{\"a}ssiger Informationssysteme auf der Basis formaler Spezifikationen zu unterst{\"u}tzen. Dazu konzentriert sich unsere Arbeit auf die Spezifikationssprache TROLL light, die es erlaubt, Teile der zu modellierenden Welt als eine Gemeinschaft nebeneinander bestehender und miteinander kommunizierender Objekte zu beschreiben. Auf diese Weise bestimmen wir sowohl die Struktur als auch das Verhalten der konzeptionellen Objekte. Unsere Spezifikationsumgebung f{\"u}r TROLL light erlaubt die Animation von Spezifikationen ebenso wie das Beweisen von Eigenschaften der Spezifikationen unter Verwendung von Theorembeweisern.}" } @INCOLLECTION{Gogolla:1993:ReportBraunschweig, AUTHOR ="Martin Gogolla", TITLE ="{Some Examples for TROLL light Templates}", BOOKTITLE="{Beitr{\"a}ge zu KORSO- und TROLL light-Fallstudien}", PUBLISHER="{Technische Universit{\"a}t Braunschweig, Informatik-Bericht Nr. 93-11}", YEAR ="{1993}", editor ="Hans-Dieter Ehrich", pages ="{51--62}", abstract="{ We introduce some small examples for templates which are given in the language TROLL light which is intended for the specification of conceptual objects in information systems. The spectrum of our examples ranges however from rather untypical information systems like clocks, counters, or flipflops over stacks and trees to more specific information system applications like libraries.}" } @INCOLLECTION{Gogolla:1993:Dagstuhl64, AUTHOR ="Martin Gogolla", TITLE ="{A Computational Model for TROLL light}", BOOKTITLE="{Specification and Semantics}", PUBLISHER="{Dagstuhl-Seminar-Report Nr. 64}", YEAR ="{1993}", editor ="Hartmut Ehrig and Friedrich von Henke and Jose Meseguer and Martin Wirsing", isbn ="ISSN~0940-112", abstract ="{ The object specification language TROLL light is intended to be used for conceptual modeling of information systems. It is designed to describe the Universe of Discourse (UoD) as a system of concurrently existing and interacting objects, i.e., an object community. The first part of the talk introduces the various language concepts offered by TROLL light. The second part of our paper outlines a simplified computational model for TROLL light. After introducing signatures for collections of object types we explain how single states of an object community are constructed. By parallel occurrence of a finite set of events the states of object communities change. The object community itself is regarded as a graph where the nodes are the object community states reachable from an initial state and the edges represent transitions between states.}" } @BOOK{Gogolla:1994:LNCS767, AUTHOR ="Martin Gogolla", TITLE ="{An Extended Entity-Relationship Model - Fundamentals and Pragmatics}", PUBLISHER="{Springer, Berlin, LNCS~767}", YEAR ="{1994}", isbn ="ISBN~3-540-57648-7", abstract ="{ This text presents a comprehensive introduction to an extended Entity-Relationship model both on a conceptual and on a formal, mathematical level. In addition to the primitives given by the data model the text introduces a language for the formulation of constraints in order to restrict database states to consistent ones. The same language can be used to query databases. The text also explains an implementation of the approach chosen in the logic programming language PROLOG and discusses in this context the computational power of the proposed calculus. Finally, the extended Entity-Relationship calculus is applied in order to define the meaning of the relational query language SQL.}" } @INPROCEEDINGS{Denker:1994:WADT, AUTHOR ="Grit Denker and Martin Gogolla", TITLE ="{Translating TROLL light Concepts to Maude}", BOOKTITLE ="{Proc. 9th Int. Workshop Abstract Data Types~(WADT'92)}", YEAR ="{1994}", editor ="Hartmut Ehrig and Fernando Orejas", pages ="{173--187}", publisher ="{Springer, Berlin, LNCS~785}", isbn ="ISBN~3-540-57867-6", abstract ="{ The specification language TROLL light is designed for the conceptual modeling of information systems. Maude is a logic programming language, which unifies the two paradigms of functional and concurrent object-oriented programming. Because of the very similar features offered by both languages, we present a translation from TROLL light concepts into the Maude language in order to compare the languages. Apart from presenting the translation, the languages are briefly described and illustrated by examples.}" } @INPROCEEDINGS{Herzig:1994:BIWIT, AUTHOR ="Rudolf Herzig and Stefan Conrad and Martin Gogolla", TITLE ="{Compositional Description of Object Communities with TROLL light}", BOOKTITLE ="{Proc. Basque Int. Workshop Information Technology~(BIWIT'94)}", YEAR ="{1994}", editor ="Chris Chrisment", pages ="{183--194}", publisher ="{Cepadues Editions, Toulouse}", isbn ="ISBN~2-85428-353-8", abstract ="{ TROLL light is a language for the modeling of information systems. It is designed to describe the Universe of Discourse (UoD) as a system of concurrently existing and interacting objects. TROLL light objects have observable properties modeled by attributes, and the behavior of objects is described by events. Possible object observations may be restricted by constraints, whereas event occurrences may be restricted to specified life cycles. TROLL light objects are organized in an object hierarchy established by subobject relationships. Communication between objects is supported by event calling. Apart from introducing the various possibilities for the syntactical description of objects, we aim to describe how the state of an object community may be changed by event occurrences.}" } @ARTICLE{Herzig:1994:Datenbankrundbrief, AUTHOR ="Rudolf Herzig and Heiko Fischer and Martin Gogolla", TITLE ="{Zur Gestaltung der Benutzeroberfl{\"a}che bei der Animation von Objektspezifikationen}", JOURNAL ="{GI Datenbankrundbrief}", YEAR ="{1994}", volume ="{13}", pages ="{43--45}", note ="{Proc. Workshop GI-Fachgruppe Datenbanken}", abstract="{ Im Rahmen des BMFT-Verbundprojekts KORSO besch{\"a}ftigt sich die Braunschweiger Gruppe mit Aspekten der Entwicklung zuverl{\"a}ssiger Informationssysteme. Der Schwerpunkt liegt dabei auf Fragen der Spezifikation, Analyse und Validierung konzeptioneller Schemata. Zu TROLL light wurde eine Entwicklungsumgebung konzipiert, deren wesentliche, bisher implementierte Bestandteile ein Parser zur syntaktischen Analyse, eine Struktur zur persistenten Ablage, ein Beweisunterst{\"u}tzungssystem zum Nachweis spezieller Eigenschaften und ein Animationssystem zur Validierung von Objektspezifikationen sind. Wir diskutieren einige Anforderungen, die an ein Werkzeug zur Unterst{\"u}tzung der Animation von TROLL light-Objektspezifikationen zu stellen sind, und gehen darauf ein, in welcher Weise diese Anforderungen in der aktuellen Implementierung der Benutzungsschnittstelle des TROLL light-Animationssystems realisiert worden sind.}" } @INPROCEEDINGS{Ehrich:1994:KORSOWorkshop, AUTHOR ="Hans-Dieter Ehrich and Martin Gogolla and Stefan Conrad and Grit Denker and Rudolf Herzig and Nikolaos Vlachantonis", TITLE ="{Entwicklung zuverl{\"a}ssiger Informationssysteme - Stand der Arbeiten im Januar'94}", BOOKTITLE ="{Korrekte Software durch formale Methoden - 6. KORSO-Workshop~(KORSO'93)}", YEAR ="{1994}", editor ="Manfred Broy and Stefan J{\"a}hnichen", pages ="{82--94}", abstract ="{ Zwei wichtige Komponenten der TROLL light-Entwicklungsumgebung sind der Animator und das Beweisunterst{\"u}tzungssystem. Der Animator dient dem Prototyping einer mit TROLL light spezifizierten Objektgesellschaft und das Beweisunterst{\"u}tzungssystem hilft beim formalen Nachweis bestimmter Eigenschaften der Spezifikation. Eine andere Komponente ist ein Tool, das den Objektansatz von TROLL light mit der etablierten Entity-Relationship-Modellierungstechnik verbindet.}" } @ARTICLE{Gogolla:1994:EMISAForum, AUTHOR ="Martin Gogolla", TITLE ="{An Extended Entity-Relationship Model - Fundamentals and Pragmatics}", JOURNAL="{GI EMISA-Forum}", YEAR ="{1994}", volume ="{1}", pages ="{80--80}", abstract ="{ This text presents a comprehensive introduction to an extended Entity-Relationship model both on a conceptual and on a formal, mathematical level. In addition to the primitives given by the data model the text introduces a language for the formulation of constraints in order to restrict database states to consistent ones. The same language can be used to query databases. The text also explains an implementation of the approach chosen in the logic programming language PROLOG and discusses in this context the computational power of the proposed calculus. Finally, the extended Entity-Relationship calculus is applied in order to define the meaning of the relational query language SQL.}" } @INPROCEEDINGS{Herzig:1995:COODBSE, AUTHOR ="Rudolf Herzig and Martin Gogolla", TITLE ="{An Animator for the Object Specification Language TROLL light}", BOOKTITLE ="{Proc. Int Colloquium Object Orientation in Databases and Software Engineering~(COODBSE'94)}", YEAR ="{1995}", editor ="Vangalur S. Alagar and Rokia Missaoui", pages ="{156--170}", publisher ="{World Scientific, River Edge (NJ)}", isbn ="ISBN~981-02-2170-3", abstract ="{ In our project we are concerned with techniques for the development of reliable information systems on the basis of their formal specification. Our work focuses on the specification language TROLL light which allows to describe the part of the world to be modeled as a community of concurrently existing and communicating objects. Our specification language comes along with an integrated, open development environment. The task of this environment is to give support for the creation of correct information systems. One important ingredient of the environment to be described here in more detail is the TROLL light animator.}" } @ARTICLE{Gogolla:1994:Datenbankrundbrief, AUTHOR ="Martin Gogolla", TITLE ="{An Extended Entity-Relationship Model - Fundamentals and Pragmatics}", JOURNAL="{GI Datenbankrundbrief}", YEAR ="{1994}", volume ="{13}", pages ="{86--86}", abstract ="{ This text presents a comprehensive introduction to an extended Entity-Relationship model both on a conceptual and on a formal, mathematical level. In addition to the primitives given by the data model the text introduces a language for the formulation of constraints in order to restrict database states to consistent ones. The same language can be used to query databases. The text also explains an implementation of the approach chosen in the logic programming language PROLOG and discusses in this context the computational power of the proposed calculus. Finally, the extended Entity-Relationship calculus is applied in order to define the meaning of the relational query language SQL.}" } @INPROCEEDINGS{Herzig:1994:ISOOMS, AUTHOR ="Rudolf Herzig and Martin Gogolla", TITLE ="{A SQL-like Query Calculus for Object-Oriented Database Systems}", BOOKTITLE ="{Proc. Int. Symposium Object-Oriented Methodologies and Systems~(ISOOMS'94)}", YEAR ="{1994}", editor ="Elisa Bertino and Susan Urban", pages ="{20--39}", publisher ="{Springer, Berlin, LNCS~858}", isbn ="ISBN~3-540-58451-X", abstract ="{ Currently much effort is being spent on providing object-oriented databases with ad hoc query facilities. In this paper we present a SQL-like query calculus whose major contribution lies in its inherent orthogonality and rigorous mathematical foundation. The calculus is essentially a calculus of complex values but it is defined independently of any concrete database model. The calculus can be used to formulate queries in value-based and object-based data models. Moreover it provides a general facility for the manipulation of complex values.}" } @TECHREPORT{Gogolla:1994:SkriptBraunschweig, AUTHOR ="Martin Gogolla", TITLE ="{Grundlagen von Entity-Relationship-Modellen}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1994}", type ="{Informatik-Skript}", number ="{33}", abstract ="{ Nach einer kurzen Motivation in der Datenbanksysteme, Datenmodelle und insbesondere semantische Datenmodelle kurz charakterisiert werden wird das Braunschweiger Erweiterte Entity-Relationship-Modell mit einem zugeh{\"o}rigen Entity-Relationship-Kalk{\"u}l samt Anwendungen des Kalk{\"u}ls vorgestellt. Es werden anschlie\ss{}end weitere semantische Datenmodelle wie IFO, ERC und OMT auf die Konzepte des vorgenannten Entity-Relationship-Modells zur{\"u}ckgef{\"u}hrt.}" } @TECHREPORT{Gogolla:1994:ReportBraunschweig, AUTHOR ="Martin Gogolla and Nikolaos Vlachantonis and Rudolf Herzig and Grit Denker and Stefan Conrad and Hans-Dieter Ehrich", TITLE ="{The KORSO Approach to the Development of Reliable Information Systems}", INSTITUTION="{Technische Universit{\"a}t Braunschweig}", YEAR ="{1994}", type ="{Informatik-Bericht}", number ="{94-06}", abstract ="{ KORSO was a joint project of fourteen university partners and one industrial partner, sponsored by the German Ministry of Research and Technology (BMFT). The project aimed at the consolidation of existing and the investigation of new methods for the development of correct software. Within this framework the focus of the KORSO group at the Technical University of Braunschweig was on the improvement of techniques for the development of reliable information systems. Our work focused on the specification language TROLL light which allows to describe the part of the world to be modeled as a community of concurrently existing and communicating objects. Our specification language comes along with an integrated, open development environment. The task of this environment is to give support for the creation of correct information systems. This report summarizes the results achieved by the Braunschweig KORSO group.}" } @INPROCEEDINGS{Gogolla:1994:ISCIS:Logic, AUTHOR ="Martin Gogolla and Sedat G{\"u}ler and Rudolf Herzig", TITLE ="{From Object Specification to Enhanced Logic Programming}", BOOKTITLE ="{Proc. 9th Int. Symposium Computer and Information Science~(ISCIS'94)}", YEAR ="{1994}", editor ="Selahattin Kuru and Ufuk Caglayan and Erol Gelenbe and Levent Akin and Cem Ersoy", pages ="{423--430}", publisher ="{Bogazici University Printhouse, Istanbul}", isbn ="ISBN~975-518-045-1", abstract ="{ We combine the area of object-oriented specification and object-oriented logic programming by indicating the translation of a specification language into an enhanced logic programming language. The translation shows that in comparison to the programming language the specification language offers richer concepts. The background of our work is the development of rapid prototyping systems for object-oriented specification languages.}" } @INPROCEEDINGS{Gogolla:1994:ISCIS:DM, AUTHOR ="Martin Gogolla", TITLE ="{On Formal Semantics of Some Semantic Data Models}", BOOKTITLE ="{Proc. 9th Int. Symposium Computer and Information Science~(ISCIS'94)}", YEAR ="{1994}", editor ="Selahattin Kuru and Ufuk Caglayan and Erol Gelenbe and Levent Akin and Cem Ersoy", pages ="{33--40}", publisher ="{Bogazici University Printhouse, Istanbul}", isbn ="ISBN~975-518-045-1", abstract ="{ We explain how different semantic data models like the ER model, the ERC approach and the OMT structural modeling method could be transformed into a semantically well-defined extended Entity-Relationship model and calculus.}" } @TECHREPORT{Herzig:1994:BremenReport, AUTHOR ="Rudolf Herzig and Martin Gogolla", TITLE ="{On a Better Formal Basis for Stating SQL-like Queries in Value- And Object-Based Database Systems}", INSTITUTION="{Universit{\"a}t Bremen}", YEAR ="{1994}", number ="{9/94}", isbn ="ISSN~0722-8996", abstract ="{ We present a formalism whose purpose is to serve as a rigid basis for describing SQL-like queries and constraints in context of both value- and object-based data models. The formalism, whose major contribution lies in its inherent orthogonality and rigorous mathematical foundation, is defined independently of any concrete database model. Instead it offers a general facility for the ad-hoc manipulation of structured values. In an improvement to the well-known relational domain or tuple calculi (or their extensions towards extended relational models) the formalism (1) guarantees safe and computable queries in an immanent way, (2) allows to explain duplicates in query results, and (3) supports the composition of queries from subqueries without the need to name intermediate query results. Hence it should be seen closer to concrete SQL than classical query calculi.}" } @ARTICLE{Gogolla:1995:TKDE, AUTHOR ="Martin Gogolla and Stefan Conrad and Grit Denker and Rudolf Herzig and Nikolaos Vlachantonis", TITLE ="{A Development Environment for an Object Specification Language}", JOURNAL ="{IEEE Transactions on Knowledge and Data Engineering}", YEAR ="{1995}", volume ="{7}", number ="{3}", pages ="{505--508}", isbn ="ISSN~1041-4347", abstract="{ Techniques for the development of reliable information systems on the basis of their formal specification are the main concern in our project. Our work focuses on the specification language TROLL light which allows to describe the part of the world to be modeled as a community of concurrently existing and communicating objects. Our specification language comes along with an integrated, open development environment. The task of this environment is to give support for the creation of correct information systems. Two important ingredients of the environment to be described here in more detail are the animator and the proof support system.}" } @TECHREPORT{Gogolla:1995:GenovaReport, AUTHOR ="Martin Gogolla and Maura Cerioli", TITLE ="{What is an Abstract Data Type, after all?}", INSTITUTION="{Dipartimento di Informatica e Scienze dell'Informazione, Universita di Genova}", YEAR ="{1995}", number ="{PDISI-95-01}", abstract ="{ We look back on ten Workshops on Abstract Data Types. A comprehensive KWIC index of titles of talks held at the workshop, a list of authors referencing their talks and publications, and a bibliography are presented.}" } @INPROCEEDINGS{Conrad:1994:OOIS, AUTHOR ="Stefan Conrad and Martin Gogolla and Rudolf Herzig", TITLE ="{Safe Derivations in Object Hierarchies}", BOOKTITLE="{Proc. Int. Conf. Object-Oriented Information Systems~(OOIS'94)}", YEAR ="{1994}", editor ="D. Patel and Y. Sun and S. Patel", pages ="{306--319}", publisher="{Springer, London}", isbn ="ISBN~3-540-19927-6", abstract ="{ We present a language for specifying structure and behavior of objects in information systems. This language is restricted to a set of core concepts for conceptual modeling. But it includes powerful concepts for specifying constraints and derived data. We present an algorithm for deciding on safe computation of derived information and demonstrate how this algorithm works with an example.}" } @INPROCEEDINGS{Gogolla:1995:WADT:Tl, AUTHOR ="Martin Gogolla and Rudolf Herzig", TITLE ="{An Algebraic Semantics for the Object Specification Language TROLL light}", BOOKTITLE="{Proc. 10th Int. Workshop Abstract Data Types~(WADT'94)}", YEAR ="{1995}", editor ="Egidio Astesiano and Gianna Reggio and Andrzej Tarlecki", pages ="{288--304}", publisher="{Springer, Berlin, LNCS~906}", isbn ="ISBN~3-540-59132-X", abstract ="{ Within the KORSO project we have developed the object specification language TROLL light which allows to describe the part of the world to be modeled as a community of concurrently existing and communicating objects. Recently, we have worked out the basic notions of a pure algebraic semantics for our language. The main underlying idea is to present a transition system where the states represent the states of the specified information system, and state transitions are caused by the occurrence of finite sets of events. This semantics is formulated by representing states and state transitions as algebras. The various constructs of TROLL light are unified to general axioms restricting the possible interpretations for TROLL light object descriptions.}" } @INPROCEEDINGS{Gogolla:1995:WADT:ADT, AUTHOR ="Martin Gogolla and Maura Cerioli", TITLE ="{What is an Abstract Data Type, after all?}", BOOKTITLE="{Proc. 10th Int. Workshop Abstract Data Types~(WADT'94)}", YEAR ="{1995}", editor ="Egidio Astesiano and Gianna Reggio and Andrzej Tarlecki", pages ="{499--523}", publisher="{Springer, Berlin, LNCS~906}", isbn ="ISBN~3-540-59132-X", abstract ="{ We look back on ten Workshops on Abstract Data Types. Organizers and publications, a list of authors referencing their talks and papers on the workshops, and a workshop bibliography are presented.}" } @INPROCEEDINGS{Gogolla:1995:AMAST, AUTHOR ="Martin Gogolla and Rudolf Herzig", TITLE ="{An Algebraic Development Technique for Information Systems}", BOOKTITLE="{Proc. 4th Int. Conf. Algebraic Methodology and Software Technology~(AMAST'95)}", YEAR ="{1995}", editor ="Vangalur S. Alagar and Maurice Nivat", pages ="{446--460}", publisher="{Springer, Berlin, LNCS~936}", isbn ="ISBN~3-540-60043", abstract ="{ This paper reports on successful application of algebraic ideas to the formal development of software systems, in particular information systems. It describes (1) a formalism, i.e., a language, for the specification of information systems, (2) a method for the construction of specifications in this language, and (3) implemented and planned parts of a specification environment covering important phases of the software development process.}" } @INPROCEEDINGS{Gogolla:1995:DEXA, AUTHOR ="Martin Gogolla", TITLE ="{Towards Schema Queries for Semantic Data Models}", BOOKTITLE="{Proc. 6th Int. Conf. and Workshop on Database and Expert Systems Applications~(DEXA'95)}", YEAR ="{1995}", editor ="Norman Revell and A Min Tjoa", pages ="{274--283}", publisher="{ONMIPRESS, San Mateo}", abstract ="{ We contribute to metadata management by giving a specification of extended Entity-Relationship schemas with the extended Entity-Relationship model itself. We formulate a number of integrity constraints describing the context-sensitive requirements an extended Entity-Relationship schema has to fulfill. By doing this, a certain class of schema queries can be formulated.}" } @INPROCEEDINGS{Gogolla:1995:KORSO, AUTHOR ="Martin Gogolla and Stefan Conrad and Grit Denker and Rudolf Herzig and Nikolaos Vlachantonis and Hans-Dieter Ehrich", TITLE ="{TROLL light - The Language and Its Development Environment}", BOOKTITLE="{KORSO - Methods, Languages, and Tools for the Construction of Correct Software~(KORSO'95)}", YEAR ="{1995}", editor ="Manfred Broy and Stefan J{\"a}hnichen", pages ="{204--220}", publisher="{Springer, Berlin, LNCS~1009}", isbn ="ISBN~3-540-60589-4", abstract ="{ In our sub-project we are concerned with techniques for the development of reliable information systems on the basis of their formal specification. Our work focuses on the specification language TROLL light which allows to describe the part of the world to be modeled as a community of concurrently existing and communicating objects. Our specification language comes along with an integrated, open development environment. The task of this environment is to give support for the creation of correct information systems. Two important ingredients of the environment to be described here in more detail are the animator and the proof support system.}" } @INPROCEEDINGS{Herzig:1995:KORSO, AUTHOR ="Rudolf Herzig and Martin Gogolla and Grit Denker", TITLE ="{KORSO Reference Languages: Concepts and Application Domains - TROLL light}", BOOKTITLE="{KORSO - Methods, Languages, and Tools for the Construction of Correct Software~(KORSO'95)}", YEAR ="{1995}", editor ="Manfred Broy and Stefan J{\"a}hnichen", pages ="{156--162}", publisher="{Springer, Berlin, LNCS~1009}", isbn ="ISBN~3-540-60589-4", abstract ="{ This paper gives an overview of the three KORSO reference languages SPECTRUM, TROLL light, and SPECIAL, exposing their motivation and background, language concepts, and typical application domains. The presentation of the different languages is followed by a discussion to what extent these languages may complement each other in the software development process.}" } @INPROCEEDINGS{Gogolla:1995:ER, AUTHOR ="Martin Gogolla", TITLE ="{A Declarative Query Approach to Object Identification}", BOOKTITLE="{Proc. 14th Int. Conf. Object-Oriented and Entity-Relationship Modelling~(ER'95)}", YEAR ="{1995}", editor ="Mike Papazoglou", pages ="{65--76}", publisher="{Springer, Berlin, LNCS~1021}", isbn ="ISBN~3-540-60672-6", abstract ="{ Object identification in data models, especially in semantic, Entity-Relationship, and object-oriented data models is studied. Various known approaches to object identification are shown, and an alternative proposal to the topic is put forward. The main new idea is to attach to each object type an arbitrary query in order to observe a unique, identifying property of objects of the corresponding type.}" } @ARTICLE{Conrad:1995:EMISA, AUTHOR ="Stefan Conrad and Grit Denker and Martin Gogolla and Rudolf Herzig and Nikolaos Vlachantonis and Hans-Dieter Ehrich", TITLE ="{Entwicklung zuverl{\"a}ssiger Informationssysteme}", JOURNAL="{GI EMISA-Forum}", YEAR ="{1995}", volume ="{2}", pages ="{25--33}", abstract ="{ Ausgehend von einem einfachen objektorientierten Ansatz zur Modellierung von Objektgesellschaften als Informationssysteme wird insbesondere eine geeignete Entwicklungsumgebung konzipiert, der Bereich Validation von Objektspezifikationen mittels Animation untersucht und ein Beweisunterst{\"u}tzungssystem entworfen, das formale Nachweise von Objekteigenschaften erm{\"o}glicht. Ziel ist die Entwicklung von Informationssystemen auf der Grundlage von objektorientierten Datenbanksystemen.}" } @INCOLLECTION{Gogolla:1995:Dagstuhl121, AUTHOR ="Martin Gogolla", TITLE ="{Identifying Objects by Declarative Queries}", BOOKTITLE="{The Role of Logics in Information Systems}", PUBLISHER="{Dagstuhl-Seminar-Report Nr. 121}", YEAR ="{1995}", editor ="Jan Chomicki and Gunter Saake and Christina Sernadas", isbn ="ISSN~0940-112", abstract ="{ In this talk we study object identification in data models, especially in semantic, Entity-Relationship, and object-oriented data models. Various known approaches to object identification are shown, and an alternative proposal to the topic is put forward. The main new idea is to attach to each object type an arbitrary query in order to observe a unique, identifying property of objects of the corresponding type. This proposal seems to be more general than the well-known ``deep equality'' approach. The talk is organized as follows. First we introduce an example schema which will be used throughout the paper, and sketch the interpretation of object schemas in an informal way. Several known and our new proposal~(the so-called observation term approach) to object identification are studied afterwards. The advantages of our new proposal are discussed, and its formal definition is mentioned. The talk ends with some concluding remarks.}" } @ARTICLE{Meyer:1996:DKE, AUTHOR ="Bernd Meyer and Gerhard D. Westerman and Martin Gogolla", TITLE ="{Drafting ER and OO Schemas in Prototyping Environments}", JOURNAL ="{Data and Knowledge Engineering}", YEAR ="{1996}", volume ="{19}", number ="{3}", pages ="{201--240}", isbn ="ISSN~0169-023X", abstract="{ The system QUEER is a prototype of an information system design tool which directly supports an extended Entity-Relationship model on its front-end and uses a semantically well-founded query and manipulation language based on an Entity-Relationship calculus. The system basically consists of a set of compilers written in PROLOG which translate data specifications, schema definitions, queries, integrity constraints, and data-manipulation statements into PROLOG programs. All features mentioned are implemented in form and extent as described here.}" } @TECHREPORT{Classen:1996:ReportBerlin, AUTHOR ="Ingo Cla\ss{}en and Martin Gogolla and Michael L{\"o}we", TITLE ="{Dynamics in Information Systems - An Algebraic Approach to Specification, Construction and Correctness}", INSTITUTION="{Technische Universit{\"a}t Berlin}", YEAR ="{1996}", type ="{Forschungsbericht}", number ="{96/01}", abstract ="{ A formal framework based on algebraic graph theory is presented that integrates specification and construction of dynamics in information systems. Specifications are based on temporal logic whose semantics is given by algebras and partial homomorphisms. Constructions are given by graph transformation rules whose operational nature provides a first step towards actual implementations. Both are related by a correctness notion. The formal framework is especially suited as a semantical basis for graphical notations as used in conceptual modeling, thus combining intuitiveness of such notations with precision of formal methods.}" } @INPROCEEDINGS{Gogolla:1996:ICCS, AUTHOR ="Martin Gogolla", TITLE ="{Towards Object Visualization by Conceptual Graphs}", BOOKTITLE="{Proc. 4th Int. Conf. Conceptual Structures~(ICCS'96), Auxiliary Proceedings}", YEAR ="{1996}", editor ="Peter W. Eklund and Gerard Ellis and Graham Mann", pages ="{175--188}", publisher="{University of New South Wales, Sydney}", isbn ="ISBN-0-7334-1387-0", abstract ="{ The specification language TROLL light allows to describe the part of the world to be modeled in the information system design process as a community of concurrently existing and communicating objects. It follows the object paradigm by coherently describing structure as well behavior of conceptual objects. A TROLL light specification is divided into a signature part and an axiom part where formulas over the signature characterizing the object are formulated. Conceptual graphs are employed to visualize object schemata as well as object instances. Thereby, we provide a uniform platform for representing static and dynamic properties of objects and reasoning about them. By giving appropriate graph substitution rules, conceptual structures are capable to express system dynamics as well.}" } @INPROCEEDINGS{Gogolla:1996:DISCO, AUTHOR ="Martin Gogolla", TITLE ="{Parameterizing Object Specifications}", BOOKTITLE="{Proc. 4th Int. Symposium Design and Implementation of Symbolic Computation Systems~(DISCO'96)}", YEAR ="{1996}", editor ="Luigia Aiello", pages ="{126--137}", publisher="{Springer, Berlin, LNCS~1128}", isbn ="ISBN-0302-9743", abstract ="{ We present a proposal for parameterized object specifications allowing especially objects sorts in the parameter. These object specifications permit to describe the part of the world to be modeled as an object community of concurrently existing and communicating objects. Our proposal for parameter passing works well on the syntactical level by means of a pushout construction. On the semantic level we use free constructions and corresponding forgetful functors.}" } @INPROCEEDINGS{Gaertner:1996:DEXA, AUTHOR ="Heino G{\"a}rtner and Martin Gogolla", TITLE ="{LASSY - A System for Analysing Grammatical Dependencies in Latin}", BOOKTITLE="{Proc. 7th Int. Workshop Database and Expert Systems Applications~(DEXA'96)}", YEAR ="{1996}", editor ="Roland R. Wagner and Helmut Thoma", pages ="{275--284}", publisher="{IEEE, Los Alamitos}", isbn ="ISBN-0-8186-7662-0", abstract ="{ We introduce the Latin analysis system Lassy, a slim system for analyzing Latin sentences. Tools for interacting with a database for morphological features are integrated as well as an interface for defining and applying a grammar database. We also give a small outline of the grammar model used in Lassy which is a pragmatic integration of linguistic theories known from both dependency and phrase structure grammar.}" } @INCOLLECTION{Gogolla:1996:Dagstuhl151, AUTHOR ="Martin Gogolla and Mark Richters", TITLE ="{An Object Specification Language Implementation with Web User Interface based on Tycoon}", BOOKTITLE="{Specification and Semantics}", PUBLISHER="{Dagstuhl-Seminar-Report Nr. 151}", YEAR ="{1996}", editor ="Hartmut Ehrig and Friedrich von Henke and Jose Meseguer and Martin Wirsing", pages ="{8--11}", isbn ="ISSN~0940-112", abstract ="{ We concentrate on the user interface of a TROLL light implementation based on Tycoon. The implementation employs a normal Web browser (Netscape, Mosaic, etc.) for both the exploration of template, i.e. object type, descriptions and objects, i.e. instances of these templates. In particular, objects are represented by HTML documents and object references can be followed simply with the Web browser.}" } @ARTICLE{Wagner:1996:FundamentaInformaticae, AUTHOR ="Annika Wagner and Martin Gogolla", TITLE ="{Defining Operational Behavior of Object Specifications by Attributed Graph Transformations}", JOURNAL ="{Fundamenta Informaticae}", YEAR ="{1996}", volume ="{3,4}", pages ="{407--431}", isbn ="ISSN~0169-2968", abstract="{ A single pushout approach to the transformation of attributed partial graphs based on categories of partial algebras and partial morphisms is introduced. A sufficient condition for pushouts in these categories is presented. As the synchronization mechanism we use amalgamation of rules and show how synchronization can be minimized. We point out how the results obtained can be employed in order to define an operational semantics for object specification languages.}" } @INPROCEEDINGS{Richters:1997:TAPSOFT, AUTHOR ="Mark Richters and Martin Gogolla", TITLE ="{A Web User Interface for an Object Specification Language}", BOOKTITLE="{Proc. 7th Int. Joint Conf. on Theory and Practice of Software Development~(TAPSOFT'97)}", YEAR ="{1997}", editor ="Michel Bidoit", pages ="{867--870}", publisher="{Springer, Berlin, LNCS~1214}", isbn ="ISBN-3-540-62781-2", abstract ="{ We present an animation tool for the formal specification language TROLL light. The system allows the manipulation and querying of objects and navigation through object hierarchies. A Web-based user interface simplifies the usage of the system.}" } @TECHREPORT{Richters:1997:jtrl, AUTHOR ="Mark Richters", TITLE ="{jtrl User Manual}", INSTITUTION="{Universit{\"a}t Bremen}", YEAR ="{1997}", type ="{Internal Report}", abstract ="{ This manual provides information on using the jtrl system for developing and validating specifications written in the TROLL light language. Such specifications are used for modeling information systems as a set of interacting and communicating objects. With jtrl a model can be validated by direct execution~(also called animation) of its specification. The manual presents all steps necessary to work with jtrl. These include instructions on system usage via the various user interfaces: command line, Web interface, and the graph visualization tool daVinci. A complete list of builtin operations and a grammar serve as reference for the language supported by jtrl.}" } @INCOLLECTION{Gogolla:1997:Dagstuhl174, AUTHOR ="Martin Gogolla and Mark Richters", TITLE ="{Web-Based Object Animation}", BOOKTITLE="{Object-Oriented Software Development}", PUBLISHER="{Dagstuhl-Seminar-Report Nr.~174}", YEAR ="{1997}", editor ="Hans-Dieter Ehrich and Yulin Feng and David Kung", pages ="{16--16}", isbn ="ISSN~0940-1121", abstract ="{ The current activities of our group comprises concrete case studies arising from practical projects: (1) Reengineering of a tram simulation system and (2) development of a material information system. Both projects use object-oriented description techniques on a semi-formal~(OMT-like) and formal~(TROLL-like) level. Semi-formal techniques are also the topic of a student project (18 students, 2 years). The aim of this student project is the development of an OMT design system. The formal basis for the above activities is the object description language TROLL light. Our group already has experience with implementations of this language on different platforms. The current implementation uses Java. The talk explains the user-interface of the current animation system which is based on HTML documents. Thus any Web browser can be employed for the validation of specifications. For demonstration purposes we use a small description of a car rentals case system.}" } @INPROCEEDINGS{Richters:1997:IDEAS, AUTHOR ="Mark Richters and Martin Gogolla", TITLE ="{A Web-based Animator for Validating Object Specifications}", BOOKTITLE="{Proc. Int. Database Engineering and Applications Symposium~(IDEAS'97)}", YEAR ="{1997}", editor ="Bipin C. Desai and Barry Eaglestone", pages ="{211--219}", publisher="{IEEE, Los Alamitos}", isbn ="ISBN-0-8186-8114-4", abstract ="{ One of the central tasks in developing information systems is the specification of desired system properties. We use the object specification language TROLL light to formalize the conceptual model of a system. A TROLL light specification describes structural as well as dynamic characteristics of objects representing real-world entities. For validating specifications, we have developed an animation tool allowing us to reflect structural properties and dynamic behavior. The main concepts of the animator are illustrated by a working example. We present a simple specification of a car rental company and describe some of the steps performed during a typical animation session. The animation allows to check whether desired properties are fulfilled by the given object descriptions. Finally, some design and implementation issues regarding the utilized persistent programming environment and the Web-based user interface are discussed.}" } @INPROCEEDINGS{Gogolla:1997:ER:Workshop, AUTHOR ="Martin Gogolla", TITLE ="{On Behavioral Model Quality and Transformation}", BOOKTITLE="{Proc. 16th Int. Conf. on Conceptual Modeling~(ER'97), Workshop on Behavioral Models and Design Transformations}", YEAR ="{1997}", editor ="Stephen W. Liddle and Stephen W. Clyde and Scott N. Woodfield", publisher="{{\verb!http://osm7.cs.byu.edu/ER97/workshop4!}}", abstract ="{ This statement reflects experience of our group in conceptual modelling with Entity-Relationship and object-oriented approaches. It describes a general view on structural and behavioral aspects of conceptual models, their interrelationships, and their transformations, and sketches a proposal to build integrated models of them.}" } @INPROCEEDINGS{Buddrus:1997:DEXA, AUTHOR ="Frank Buddrus and Heino G{\"a}rtner and Sven-Eric Lautemann", TITLE ="{First Steps to a Formal Framework for Multilevel Database Modifications}", BOOKTITLE="{Proc. 8th Int. Conf. Database and Expert Systems Applications~(DEXA'97)}", YEAR ="{1997}", editor ="A. Hameurlain and A Min Tjoa", pages ="{240--251}", publisher="{Springer, Berlin, LNCS~1308}", abstract ="{ We propose a formal basis for operations which can be understood as implicitly used in many kinds of schema modifications. Approaches for view definition, schema evolution, and schema versioning all rely on operations which work either on instance, on schema, or on both levels. This paper discusses a basic set of these operations called modification primitives and describes their semantics on the basis of the Extended Entity Relationship (EER) Model in a Hoare-style notation. We focus on the structural part of the schema definition and outline our ideas for arbitrary manipulations of instances.}" } @INPROCEEDINGS{Gaertner:1997:COMAD, AUTHOR ="Heino G{\"a}rtner", TITLE ="{Perspectives for a Formal Framework for Schema Modification in Object Databases}", BOOKTITLE="{Proc. 8th Int. Conf. Management of Data~(COMAD'97)}", YEAR ="{1997}", editor ="D.J. Ram", pages ="{238--249}", publisher="{Narosa, New Delhi}", abstract ="{ This paper proposes a formal basis for the description of schema modification in object databases. We identify three necessary building blocks for the structural aspect of such a description: (i)~basic schema and database objects, (ii)~properties of (classes of) schema and database objects, and (iii)~schema modifications, i.e. transitions between schemata and transitions between database states. The semantics for the basic schema and database objects is given in a denotational style. Properties of schemata can be described as formulas. For schema modification we introduce a set of schema modification primitives and describe their semantics by means of pre- and postcondition in a Hoare-style notation. We focus on the structural aspects of schema modification and describe some simple properties of our framework.}" } @INPROCEEDINGS{Gogolla:1998:WADT, AUTHOR ="Martin Gogolla and Mark Richters", TITLE ="{On Combing Semi-Formal and Formal Object Specification Techniques}", BOOKTITLE ="{Proc. 12th Int. Workshop Abstract Data Types~(WADT'97)}", YEAR ="{1998}", editor ="Francesco Parisi-Presicce", pages ="{238-252}", publisher ="{Springer, LNCS~1376}", isbn ="ISBN~3-540-64299-4", abstract ="{ In the early phases of software development it seems profitable to freely mix semi-formal and formal design techniques. Formal techniques have their strength in their ability to rigorously define desired software qualities like functionality, whereas semi-formal methods are usually said to be easier to understand and to be more human-nature oriented. We propose a new approach in order to combine these two areas by exploiting how constructs of the formal specification language TROLL light are related to the graphical elements of the UML approach.}" } @TECHREPORT{Gogolla:1997:RomeReport, AUTHOR ="Martin Gogolla and Francesco Parisi-Presicce", TITLE ="{State Diagrams in UML~- A Formal Semantics using Graph Transformation}", INSTITUTION="{University of Rome `La Sapienza', Dipartimento di Scienze dell'~Informazione}", YEAR ="{1997}", type ="{Rapporto di Ricerca}", number ="{97/15}", abstract ="{ We show how to transform UML~(Unified Modeling Language) state diagrams into graphs by making explicit the intended semantics of the diagram. The process of state expansion in nested state diagrams is explained by graph transformations in three steps: (1)~adding boundary nodes introducing a precise interface for the state to be expanded, (2)~expanding the state, and (3)~ removing the boundary nodes. The general idea of approaching the semantics of UML diagrams by graph transformations is applicable to other forms of UML diagrams as well. The main advantage of the graph transformation approach is the closeness between the (mathematical) graph representation and the~(UML) diagram representation.}" } @INPROCEEDINGS{Gogolla:1997:UMLWS, AUTHOR ="Martin Gogolla and Mark Richters", TITLE ="{On Constraints and Queries in UML}", BOOKTITLE ="{Proc. UML'97 Workshop `The Unified Modeling Language - Technical Aspects and Applications'}", YEAR ="{1997}", editor ="Martin Schader and Axel Korthaus", pages ="{109--121}", publisher ="{Physica-Verlag, Heidelberg}", isbn ="ISBN~3-7908-1105-X", abstract ="{ The UML has recently been extended by an Object Constraint Language~(OCL). This formal language can be used for specifying constraints on a model in order to restrict possible system states. We present some examples for illustrating main concepts of OCL. Problems with the current definition of OCL resulting from imprecise or ambiguous definitions are investigated. A comparison of OCL with a language for specification of queries and integrity constraints in an Extended Entity-Relationship model shows similarities between both approaches. This comparison could lead to a better understanding of OCL.}" } @INPROCEEDINGS{Gogolla:1998:PSMT, AUTHOR ="Martin Gogolla and Francesco Parisi-Presicce", TITLE ="{State Diagrams in UML~- A Formal Semantics using Graph Transformation}", BOOKTITLE ="{Proc. ICSE'98 Workshop on Precise Semantics of Modeling Techniques~(PSMT'98)}", YEAR ="{1998}", editor ="Manfred Broy and Derek Coleman and Tom Maibaum and Bernhard Rumpe", pages ="{55-72}", publisher ="{Technical University of Munich, Technical Report TUM-I9803}", abstract ="{ We show how to transform UML~(Unified Modeling Language) state diagrams into graphs by making explicit the intended semantics of the diagram. The process of state expansion in nested state diagrams is explained by graph transformations in three steps: (1)~adding boundary nodes introducing a precise interface for the state to be expanded, (2)~expanding the state, and (3)~ removing the boundary nodes. The general idea of approaching the semantics of UML diagrams by graph transformations is applicable to other forms of UML diagrams as well. The main advantage of the graph transformation approach is the closeness between the (mathematical) graph representation and the~(UML) diagram representation.}" } @INPROCEEDINGS{Gogolla:1998:UMLWS, AUTHOR ="Martin Gogolla and Mark Richters", TITLE ="{Transformation Rules for UML Class Diagrams}", BOOKTITLE ="{Proc. 1st Int. Workshop Unified Modeling Language~(UML'98)}", YEAR ="{1999}", editor ="Jean Bezivin and Pierre-Alain Muller", pages ="{92--106}", publisher ="{Springer, Berlin, LNCS~1618}", isbn ="ISBN~3-540-66252-9", abstract ="{ UML is a complex language with many modeling features. Especially the modeling of static structures with class diagrams is supported by a rich set of description primitives. We show how to transfrom UML class diagrams involving cardinality constraints, qualifiers, association classes, aggregations, compositions, and generalizations into equivalent UML class diagrams employing only n-ary associations and OCL constraints. This provides a better understanding of UML features. By explaining more complex features in terms of basic ones, we suggest an easy way users can gradually extend the set of UML elements they commonly apply in the modeling process.}" } @TECHREPORT{Gogolla:1998:BremenReport, AUTHOR ="Martin Gogolla", TITLE ="{UML for the Impatient}", INSTITUTION="{Universit{\"a}t Bremen}", YEAR ="{1998}", type ="{Research Report}", number ="{3/98}", isbn ="ISSN~0722-8996", abstract ="{ By examples we give a short introduction into the nine diagram forms provided by the Unified Modeling Language~(UML). The running example we use is a small traffic light system which we first formally describe in an object specification language. Afterwards, central aspects of the specification and the specified system are visualized with UML constructs. As a conclusion, we discuss a classification of the various UML diagram forms.}" } @INPROCEEDINGS{Gogolla:1998:DEXA, AUTHOR ="Martin Gogolla and Anne Kathrin Huge and Bodo Randt", TITLE ="{Stepwise Re-Engineering and Development of Object-Oriented Database Schemata}", BOOKTITLE ="{Proc. 9th Int. Workshop Database and Expert Systems Applications~(DEXA'98)}", YEAR ="{1998}", editor ="Roland R. Wagner", OPTpages ="", publisher ="{IEEE, Los Alamitos}", OPTisbn ="", abstract ="{ We present a general approach for re-engineering of object-oriented database schemata. The approach consists of four dependent steps: (1)~description of the data within the underlying basic data format, (2)~application of a powerful semantic data model in order to construct a semantic database schema, (3)~translation of the achieved schema into a general object model, and (4)~implementation of the object schema in a concrete object-oriented database system. As an instantiation of this general procedure we report on a case study carried out in an industrial context where an Extended Entity-Relationship model was used as the semantic data model and ObjectStore as the implementation platform.}" } @INPROCEEDINGS{Richters:1998:ER, AUTHOR ="Mark Richters and Martin Gogolla", TITLE ="{On Formalizing the UML Object Constraint Language OCL}", BOOKTITLE="{Proc. 17th Int. Conf. Conceptual Modeling~(ER'98)}", YEAR ="{1998}", editor ="Tok-Wang Ling and Sudha Ram and Mong Li Lee", pages ="{449--464}", publisher="{Springer, Berlin, LNCS~1507}", isbn ="ISBN~3-540-65189-6", abstract ="{ We present a formal semantics for the Object Constraint Language (OCL) which is part of the Unified Modeling Language (UML) -- an emerging standard language and notation for object-oriented analysis and design. In context of information systems modeling, UML class diagrams can be utilized for describing the overall structure, whereas additional integrity constraints and queries are specified with OCL expressions. By using OCL, constraints and queries can be specified in a formal yet comprehensible way. However, the OCL itself is currently defined only in an informal way. Thus the semantics of constraints is in general not precisely defined. Our approach gives precise meaning to OCL concepts and to some central aspects of UML class models. In consequence, a formal semantics facilitates verification, validation and simulation of models improving the quality of models and software design.}" } @TECHREPORT{Richters:1998:SIGN, AUTHOR ="Mark Richters and Martin Gogolla and Heino G{\"a}rtner", TITLE ="{SIGN - Software Implementierung durch Graphische Notation}", INSTITUTION="{Universit{\"a}t Bremen, Fachbereich~3}", YEAR ="{1998}", type ="{Interner Bericht}", abstract ="{ Das studentische Projekt SIGN~(Software Implementierung durch Graphische Notation) wurde an der Universit{\"a}t Bremen von 1996 bis 1998 durchgef{\"u}hrt. Ziel des Projektes war die Entwicklung einer graphischen Modellierungssprache zur Unterst{\"u}tzung des objektorientierten Systementwurfs. Zur praktischen Umsetzung der Modellierungssprache wurde au\ss{}erdem eine Entwicklungsumgebung entworfen und implementiert. Sowohl Sprache als auch das Entwicklungssystem wurden durchgehend objektorientiert entwickelt. Dabei wurde im Rahmen der Metamodellierung auch die zu entwerfende Sprache selbst eingesetzt. Dieses Papier fa\ss{}t die Ziele, Methoden und Ergebnisse des Projektes zusammen.}" } @BOOK{Cerioli:1998:CompassBiblio, EDITOR ="Maura Cerioli and Martin Gogolla and Helene Kirchner and Bernd Krieg-Br{\"u}ckner and Zhenyu Qian and Markus Wolf", TITLE ="{Algebraic System Specification and Development~- Survey and Annotated Bibliography}", PUBLISHER="{Shaker, Aachen}", YEAR ="{1998}", series ="{Monographs of the Bremen Institute of Safe Systems~(BISS)}", isbn ="{ISBN~3-8265-4067-0}", abstract ="{ This book is an annotated bibliography that attempts to provide an up-to-date overview of most past and present work on algebraic specification for researchers in algebraic specification and neighbouring fields. It extends the previous annotated bibliography by Bidoit, Kreowski, Lescanne, Orejas and Sannella. A review of the main topics of current and past research is given, with some indication of how the different approaches are related and pointers to relevant papers.}" } @INCOLLECTION{Wagner:1999:GraGraHandbook, AUTHOR ="Annika Wagner and Martin Gogolla", TITLE ="{Semantics of Object-Oriented Languages}", BOOKTITLE="{Handbook of Graph Grammars and Computing by Graph Transformation, Volume II, Applications, Languages, and Tools}", PUBLISHER="{World Scientific, Singapore}", YEAR ="{1999}", editor ="Hartmut Ehrig and Gregor Engels and Hans-J{\"o}rg Kreowski and Gregorz Rozenberg", pages ="{181--211}", abstract ="{Graph transformations can be applied everywhere, where graphs are used as a natural and intuitive description of complex phenomena. One field where this is the case is object modeling. The important role graphs play during object-oriented analysis and design shows their usefulness in the context of object orientation. A main characteristic of graph transformations is its direct operational executability. Combining both observations, it seems to be natural to use graph transformations to specify the operational behavior of objects. In this contribution we follow this idea by providing an operational semantics for the textual object description language TROLL~{\em light} by means of graph transformations. But this is not the only possible application of graph transformations in the object-oriented field because what we are doing can be used also in combination with the graphical object modeling language UML.}" } @INPROCEEDINGS{Gogolla:1999:ECOOPWorkshop, AUTHOR ="Martin Gogolla and Oliver Radfelder and Mark Richters", TITLE ="{A UML Semantics FAQ - The View from Bremen}", BOOKTITLE ="{Proc. ECOOP'99 Workshop UML Semantics FAQ}", YEAR ="{1999}", editor ="S.J.H. Kent and A. Evans and B. Rumpe", publisher ="{University of Brighton}", abstract ="{ This note spells out questions the authors found while studying the material defining the Unified Modeling Language UML. After formulating a preliminary question in Sec.~1, some detailed questions with answers and some detailed questions without answers are given in Sec.~2 and~3, respectively. Sections~4 and~5 just state questions with and without answers but we do not go into details explaining the importance of the questions. Our answers to the `questions with answers' can be found in our recent. In Sec.~6, a short hint to relevant literature ends this note.}" } @MISC{Gogolla:1999:MITBook, author ="Martin Gogolla", title ="{Identifying Objects by Declarative Queries}", howpublished="{Advances in Object-Oriented Data Modeling. M.P. Papazoglou, S. Spaccapietra, Z. Tari~(Eds.), MIT Press. pages 255-277}", year ="{1999}", isbn ="ISBN~0-262-16189-3", abstract ="{ Object identification in data models, especially in semantic, Entity-Relationship, and Object-Oriented data models is studied. Various known approaches to object identification are shown, and an alternative proposal to the topic is put forward. The main new idea is to attach to each object type an arbitrary query, a so-called observation term, in order to observe a unique, identifying property of objects of the corresponding type.}" } @INPROCEEDINGS{Radfelder:1999:ISCIS, AUTHOR ="Oliver Radfelder and Martin Gogolla and Volker Behr", TITLE ="{On Designing and Querying a Material Information System}", BOOKTITLE ="{Proc. 14th Int. Symposium Computer and Information Science~(ISCIS'99)}", YEAR ="{1999}", editor ="M. T{\"u}rksever and N.Y. Topaloglu and N. Zincir-Heywood and A. Kantarci and C.A. S{\"u}rgevil and {\"O}. {\"O}zmen", publisher ="{Ege University, Izmir}", pages ="{132--142}", isbn ="ISBN~975-483-422-9", abstract ="{We present an information system which has been developed in cooperation with a composite material development laboratorium and other industrial partners. The system enables people interested in this field to get knowledge about project participants and their offers. The main purpose of the development was to let all the involved people participate regardless of their technical skills. One precondition to achieve this goal was the development of an easy-to-learn graphical query language. The implementation has been led by the demand for platform independence and the necessity to involve the project participants in the maintenance of the data.}" } @INPROCEEDINGS{Richters:1999:UML, AUTHOR ="Mark Richters and Martin Gogolla", TITLE ="{A Metamodel for OCL}", BOOKTITLE="{Proc. 2nd Int. Conf. Unified Modeling Language~(UML'99)}", YEAR ="{1999}", editor ="Robert France and Bernhard Rumpe", pages ="{156--171}", publisher="{Springer, Berlin, LNCS~1723}", isbn ="ISBN~3-540-66712-1", abstract ="{The Object Constraint Language (OCL) allows the extension of UML models with constraints in a formal way. While the UML itself is defined by following a metamodeling approach, there is currently no equivalent definition for the OCL\@. We propose a metamodel for OCL that fills this gap. The benefit of a metamodel for OCL is that it precisely defines the syntax of all OCL concepts like types, expressions, and values in an abstract way and by means of UML features. Thus, all legal OCL expressions can be systematically derived and instantiated from the metamodel. We also show that our metamodel smoothly integrates with the UML metamodel. The focus of this work lies on the syntax of OCL; the metamodel does not include a definition of the semantics of constraints.}" } @INPROCEEDINGS{Gogolla:1999:UML, AUTHOR ="Martin Gogolla and Oliver Radfelder and Mark Richters", TITLE ="{Towards Three-Dimensional Representation and Animation of UML Diagrams}", BOOKTITLE="{Proc. 2nd Int. Conf. Unified Modeling Language~(UML'99)}", YEAR ="{1999}", editor ="Robert France and Bernhard Rumpe", pages ="{489--502}", publisher="{Springer, Berlin, LNCS~1723}", isbn ="ISBN~3-540-66712-1", abstract ="{The UML notation is intended to be drawn on two-dimensional surfaces. However, three-dimensional diagram layout and animation may improve comprehension of complex diagrams significantly. The paper concentrates on special UML diagram forms well-suited for advanced visualization. It makes a proposal for representing and animating such UML diagrams in a three-dimensional style.}" } @INPROCEEDINGS{Astesiano:1999:ECOOP-UML-FAQ, AUTHOR ="Astesiano, Egidio and Evans, Andy and France, Robert and Geniloud, Guy and Gogolla, Martin and Henderson-Sellers, Brian and Howse, John and Hussmann, Heinrich and Iida, Shusaku and Kent, Stuart and Le Guennec, Alain and Mens, Tom and Mitchell, Richard and Radfelder, Oliver and Reggio, Gianna and Richters, Mark and Rumpe, Bernhard and Stevens, Perdita and van den Berg, Klaas and van den Broek, Pim and Wieringa, Roel", TITLE ="{UML Semantics FAQ}", BOOKTITLE ="{ECOOP'99 Workshop Reader}", YEAR ="{1999}", editor ="Ana Moreira and Serge Demeyer", pages ="{33--56}", isbn ="3-540-66954-X", publisher ="{Springer, Berlin, LNCS~1743}", abstract ="{This paper reports the results of a workshop held at ECOOP'99. The workshop was set up to find answers to questions fundamental to the definition of a semantics for the Unified Modelling Language. Questions examined the meaning of the term semantics in the context of UML; approaches to defining the semantics, including the feasibility of the meta-modelling approach; whether a single semantics is desirable and, if not, how to set up a framework for defining multiple, interlinked semantics; and some of the outstanding problems for defining a semantics for all of UML.}" } @INPROCEEDINGS{Radfelder:2000:AVI, AUTHOR ="Radfelder, Oliver and Gogolla, Martin", TITLE ="{On Better Understanding UML Diagrams through Interactive Three-Dimensional Visualization and Animation}", BOOKTITLE ="{Proc. Advanced Visual Interfaces~(AVI'2000)}", YEAR ="{2000}", editor ="Vito Di Gesu and Stefano Levialdi and Laura Tarantino", pages ="{292--295}", isbn ="ISBN~1-58113-252-2", publisher ="{ACM Press, New York}", abstract ="{Different approaches support the construction of software by representing certain aspects of a system graphically. Recently, the UML has become common to provide software designers with tools, in which they can create visual representations of software interactively. But the UML is intended to be drawn on two-dimensional surfaces. Our approach extends UML into a third and fourth dimension in a way that we can place both static and dynamic aspects in one single view. By this, we can show behavior in the context of structural aspects, instead of drawing different diagrams for each aspect with only loose relation to each other. We also use the third dimension to emphasize important things and to place less interesting things in the background. Thereby, we direct the viewer's attention to the important things in the foreground. Currently, UML shows dynamic behavior by diagrams which do not change and are therefore static in nature. In sequence diagrams, for example, time elapses from the top of the diagram to the bottom. We point out that behavior is better visualized by animated diagrams where message symbols move from the sender object to the receiver object. Our approach supports the creation of a system as well as the communication of its dynamic processes especially to customers.}" } @INPROCEEDINGS{Gogolla:2000:GROOM, AUTHOR ="Gogolla, Martin and Richters, Mark", TITLE ="{Definition von UML mit UML und OCL: Ein {\"U}berblick zum Stand der Technik}", BOOKTITLE ="{Proc. 7. GROOM-Workshop ``UML - Erweiterungen (Profile) und Konzepte der Metamodellierung''}", YEAR ="{2000}", editor ="Mario Jeckle and Bernhard Rumpe and Andy Sch{\"u}rr and Andreas Winter", publisher ="{Universit{\"a}t Koblenz-Landau, Fachbereich Informatik}", note ="{Auch: Softwaretechnik-Trends, 20:2, 2000, ISSN~0720-8928}", abstract ="{Das Ziel dieser Arbeit ist es, einen {\"U}berblick zum Einsatz der Object Constraint Language OCL zum einen bei der Beschreibung von Modellen mit der Unified Modeling Language UML und zum anderen bei der Beschreibung des UML-Metamodells zu vermitteln. Eingang in die {\"U}berlegungen finden die Dokumente des UML-Standards, eigene Arbeiten und weitere Papiere anderer Arbeitsgruppen.}" } @INPROCEEDINGS{Richters:1999:OOPSLA-WS, AUTHOR ="Richters, Mark and Gogolla, Martin", TITLE ="{On the Need for a Precise OCL Semantics}", BOOKTITLE ="{Proc. OOPSLA Workshop ``Rigorous Modeling and Analysis with the UML: Challenges and Limitations''}", YEAR ="{1999}", editor ="Robert France and Bernhard Rumpe and Brian Henderson-Sellers and Jean-Michel Bruel and Ana Moreira", publisher ="{Colorado State University, Fort Collins, Colorado}", abstract ="{In our view a formalization of the OCL is beneficial for achieving the following goals: (1) Improvement of the OCL itself by pointing out some potential problems with its current definition, (2) a more precise understanding of UML class models and their interpretation, (3) a solid foundation for implementing CASE tools supporting analysis, simulation and validation of UML models. We also feel that there is one aspect of OCL which often gets underrated. OCL expressions cannot only be used to specify constraints, but more generally, one can utilize them to specify queries retrieving non-trivial information about certain objects in a given system state. These queries can then be translated into statements of a query language of the chosen implementation environment. A precise OCL semantics would obviously facilitate a more systematic description of a translation scheme from OCL to e.g. SQL or the ODMG's Object Query Language (OQL).}" } @PHDTHESIS{Gaertner:2000:diss, AUTHOR ="Heino G{\"a}rtner", TITLE ="{Schematransformationen in objektorientierten Informationssystemen}", SCHOOL ="{Universit{\"a}t Bremen, Fachbereich Mathematik und Informatik}", YEAR ="{2000}", address="{Shaker Verlag, Aachen}", isbn ="ISBN~3-8265-6542-8", abstract ="{Die vorliegende Arbeit konzentriert sich auf die Untersuchung der vertikalen Schemaevolution und geht dabei wie folgt vor: Nachdem im folgenden Abschnitt die ben{\"o}tigten Grundbegriffe aus dem Bereich der konzeptionellen Modellierung und der Schemaevolution gekl{\"a}rt worden sind, folgt zun{\"a}chst die Pr{\"a}sentation eines einfachen Objektmodells, das im wesentlichen die Konzepte des ER-Modells umfa\ss{}t. Danach werden die Grundlagen von Schematransformation diskutiert und eine formal begr{\"u}ndete Notation zur Beschreibung von atomaren Schema{\"a}nderungsoperationen, Schematransformationsprimitiven, vorgestellt. Mit Hilfe dieser Notation werden zun{\"a}chst Transformationen auf den Konstrukten des einfachen Objektmodells beschrieben. Danach wird das einfache Objektmodell schrittweise um weitergehende Konzepte erweitert und deren Transformationsm{\"o}glichkeiten in dem pr{\"a}sentierten Rahmen diskutiert. Im darauf folgenden Abschnitt werden schlie\ss{}lich Transformationen von Spezifikationsanteilen, die {\"u}ber die Modellierung struktureller Information hinausgehen, am Beispiel von Objektlebensl{\"a}ufen erl{\"a}utert. Im vorletzten Abschnitt wird die Perspektive der Spezifikation verlassen und er{\"o}rtert, wie sich der vorgestellte Ansatz in den Softwareentwicklungsproze\ss{} integrieren l{\"a}\ss{}t. Eine Einordnung in die bisherige Forschung und ein Ausblick auf k{\"u}nftige Entwicklungsm{\"o}glichkeiten beschlie\ss{}t die Arbeit.}" } @PHDTHESIS{Huge:2000:diss, AUTHOR ="Anne Kathrin Huge", TITLE ="{Formalisierung objektorientierter Datenbanken auf der Grundlage von ODMG}", SCHOOL ="{Universit{\"a}t Bremen, Fachbereich Mathematik und Informatik}", YEAR ="{2000}", address="{Shaker Verlag, Aachen}", isbn ="ISBN~3-8265-7346-8", abstract ="{Die Untersuchung objektorientierter Methoden zeigt, da\ss{} die Bereitstellung einer formalen Grundlage ein h\"aufiges Problem ist. Dabei stellt gerade eine formale Grundlage die Basis f\"ur ein eingehendes Verst\"andnis der Semantik von Modellierungs- und Spracheigenschaften dar. Ein vergleichender R\"uckblick auf die generelle Entwicklung von Datenbanken ergibt, da\ss{} sich insbesondere das relationale Datenbankmodell auf eine wohldefinierte formale Grundlage st\"utzt und somit den weitreichenden Erfolg relationaler Datenbanksysteme (inklusive SQL) begr\"undet. Ausgehend von diesen Beobachtungen wird in dieser Arbeit eine formale Grundlage f\"ur objektorientierte Datenbanken auf der Grundlage des ODMG-Standards vorgestellt. Der ODMG-Standard vereinheitlicht die Konzepte objektorientierter Datenbanken und erm\"oglicht Portabilit\"at. Um die L\"ucke zwischen der informellen Beschreibung von ODMG-Sprachkonstrukten und den theoretischen Grundlagen zu schlie\ss{}en, wird in dieser Arbeit ein mengentheoretischer Ansatz zur Beschreibung des ODMG-Objektmodells und der Anfragesprache OQL vorgestellt. Nach einer eher informellen Vorstellung der Konzepte des ODMG-Modells und deren Einbettung in die allgmeinen Konzepte objektorientierter Datenbanken und anschlie\ss{}ender vergleichenden Darstellung mit anderen objektorientierten Datenmodellen und Modellierungssprachen wird eine formale Beschreibung des ODMG-Modells und der OQL vorgenommen. Die Formalisierung beruht auf einem Zwei-Schichten-Ansatz, wonach zwischen einer Datenschicht und einer Objektebene differenziert wird. Auf dies Weise erfolgt eine strikte Trennung zwischen unver\"anderlichen Datentypen und ver\"anderlichen Objekttypen. Um eine konsistente Implementierung einer ODMG-Objektmodell-Spezifikation in einer der Sprachanbindungen (C++, Smalltalk, Java) zu gew\"ahrleisten, wird eine Transformation der Konstrukte des ODMG-Modells auf die entsprechenden Konstrukte der Sprachanbindungen vorgestellt.}" } @INPROCEEDINGS{Gogolla:2000:euroREF, AUTHOR ="Gogolla, Martin and Kollmann, Ralf", TITLE ="{Re-Documentation of Java with UML Class Diagrams}", BOOKTITLE ="{Proc. 7th Reengineering Forum, Reengineering Week 2000 Z{\"u}rich}", YEAR ="{2000}", editor ="Eliot Chikofsky", pages ="{REF~41--REF~48}", publisher ="{Reengineering Forum, Burlington, Massachusetts}", abstract ="{This paper describes the generation of class diagrams characterizing the static data and class structure of Java source code. To achieve such a diagrammatic representation, translation rules are defined that transform Java syntax into UML notation. Attention is paid especially to implicit and advanced properties of associations. First, an implementation view class diagram of the Java source code is generated that reflects program-specific details of the source code. In a second, more involved step, we try to create a design view from the source code and also represent certain patterns as ODMG language features. The focus of our approach is on minimizing the resulting UML diagrams (minimal with respect to the number of elements in the diagrams) by recognizing certain patterns in the source code and transforming certain low-level syntactic constructs into high-level semantic UML features.}" } @INPROCEEDINGS{Gogolla:2000:GraGra, AUTHOR ="Gogolla, Martin", TITLE ="{Graph Transformations on the UML Metamodel}", BOOKTITLE ="{Proc. ICALP Workshop Graph Transformations and Visual Modeling Techniques~(GTVMT'2000)}", YEAR ="{2000}", editor ="Jose D.P. Rolim and Andrei Z. Broder and Andrea Corradini and Roberto Gorrieri and Reiko Heckel and Juraj Hromkovic and Ugo Vaccaro and Joe B. Wells", pages ="{359--371}", isbn ="ISBN~1-894145-07-0", publisher ="{Carleton Scientific, Waterloo, Ontario, Canada}", abstract ="{The Unified Modeling Language~UML is a rich language so that it seems not feasible to give a single semantics for the complete language in one step. In order to define the semantics, we propose to translate as many UML language features as possible into UML itself. The part of UML which cannot be treated in this way is called the UML core. The semantics of the non-core language features is given by a translation into the core, whereas a different semantics~(for example a set-theoretic one or a semantics on the basis of graphs) must be given to the UML core. It turns out that for the first step, namely the translation of UML language features into the UML core, graph transformations are an ideal language for expressing the required manipulations and the UML metamodel gives the necessary fundamental vocabulary and notions.}" } @INPROCEEDINGS{Barbier:2000:UMLAnalysisDesignDevelopment, AUTHOR ="Franck Barbier and Brian Henderson-Sellers and Andreas Opdahl and Martin Gogolla", TITLE ="{The Whole-Part Relationship in Object-Oriented Modeling}", BOOKTITLE ="{Unified Modeling Language: Systems Analysis, Design, and Development Issues}", YEAR ="{2001}", editor ="Keng Siau and Terry Halpin", pages ="{186--209}", isbn ="ISBN~1-930708-05-X", publisher ="{Idea Group Publishing, Hershey~(PA), USA}", abstract ="{This study of the semantics of the Whole-Part relationship in OO modelling is based on previous detailed analysis of the semantics of UML's Aggregation and Composition (white and black diamonds). Although UML is nowadays a standard and an intensively used OO modelling language, the way the Whole-Part is formalised is unsatisfactory. In this respect, we provide a complete specification by using OCL (Object Constraint Language). This is based on a separation between primary characteristics assigned to the "Whole-Part" metatype, considered as necessary in the metamodel of UML, and secondary features possessed by subtypes of this metatype. This UML-compliant style of specification, based on the use of OCL as well as metamodelling, allows us to directly incorporate our results into the metamodel, in particular to revise UML's definition of Composition.}" } @INPROCEEDINGS{Richters:2000:UML, AUTHOR ="Mark Richters and Martin Gogolla", TITLE ="{Validating UML Models and OCL Constraints}", BOOKTITLE ="{Proc. 3rd Int. Conf. Unified Modeling Language~(UML'2000)}", YEAR ="{2000}", editor ="Andy Evans and Stuart Kent", pages ="{265-277}", publisher ="{Springer, Berlin, LNCS~1939}", abstract ="{The UML has been widely accepted as a standard for modeling software systems and is supported by a great number of CASE tools. However, UML tools often provide only little support for validating models early during the design stage. Also, there is generally no substantial support for constraints written in the Object Constraint Language (OCL). We present an approach for the validation of UML models and OCL constraints that is based on animation. The \USE{} tool (UML-based Specification Environment) supports developers in this process. It has an animator for simulating UML models and an OCL interpreter for constraint checking. Snapshots of a running system can be created, inspected, and checked for conformance with the model. As a special case study, we have applied the tool to parts of the UML~1.3 metamodel and its well-formedness rules. The tool enabled a thorough and systematic check of the OCL well-formedness rules in the UML standard.}" } @INPROCEEDINGS{Richters:2000:GI, AUTHOR ="Mark Richters and Martin Gogolla", TITLE ="{Validierung von UML-Modellen und OCL-Bedingungen}", BOOKTITLE ="{Proc. GI'2000 Workshop Rigorose Entwicklung software-intensiver Systeme}", YEAR ="{2000}", editor ="Martin Wirsing and Martin Gogolla and Hans-J{\"o}rg Kreowski and Tobias Nipkow and Wolfgang Reif", pages ="{21--32}", publisher ="{LMU M{\"u}nchen, Informatik-Bericht Nr.~0005}", abstract ="{Die Unified Modeling Language (UML) ist ein allgemein akzeptierter Standard f{\"u}r die Modellierung von Software-Systemen und wird als solcher von einer großen Anzahl von CASE-Tools unterst{\"u}tzt. Oft weisen UML-Werkzeuge nur wenig Unterst{\"u}tzung f{\"u}r die Validierung von Modellen in fr{\"u}hen Entwurfsphasen auf. Es gibt im allgemeinen auch keine nennenswerte Unterst{\"u}tzung f{\"u}r Integrit{\"a}tsbedingungen, die in der Object Constraint Language (OCL) geschrieben sind. Wir stellen daher einen Ansatz f{\"u}r die Validierung von UML-Modellen und OCL-Bedingungen vor, der diese Unterst{\"u}tzung bereitstellt. Das USE-Werkzeug (UML-based Specification Environment) bietet einen Animator zum Simulieren von UML-Modellen und einen OCL-Interpreter f{\"u}r die {\"u}berpr{\"u}fung von Bedingungen. Einzelne Zust{\"a}nde eines laufenden Systems k{\"o}nnen untersucht und auf {\"u}bereinstimmung mit dem Modell {\"u}berpr{\"u}ft werden.}" } @INPROCEEDINGS{Gogolla:2000:UML-DYN-WS, AUTHOR ="Martin Gogolla and Oliver Radfelder and Ralf Kollmann and Mark Richters", TITLE ="{Analysing Atomic Dynamic UML Notions by Surfing through the UML Metamodel}", BOOKTITLE ="{Proc. UML'00 Workshop Dynamic Behaviour in UML Models}", YEAR ="{2000}", editor ="Gianna Reggio and Alexander Knapp and Bernhard Rumpe and Bran Selic and Roel Wieringa", pages ="{57-62}", publi