A semi-automated Framework for Supporting Semantic Image Annotation (2009)
Johanna Vompras, Stefan Conrad
Abstract. Advanced semantic description of multimedia data significantly improves representing, labeling, and retrieving multimedia-based contents. In this paper we present an intelligent framework...
Richard Wages, Benno Grützmacher, Stefan Conrad
Abstract. Any movie production needs a whole group of contributing authors and creative artists from various fields. The same should obviously be true for the making of a compelling VR scenario....
ABSTRACT Adding Conflict Resolution Features to a Query Language for Database Federations * (2008)
Kai-uwe Sattler, Stefan Conrad, Gunter Saake
A main problem of data integration is the treatment of conflicts caused by different modeling of real-world entities, different data models or simply by different representations of one and the same...
Link Patterns for Modeling Information Grids (2008)
And Networks Christopher, Christopher Popfinger, Stefan Conrad
Collaborative work requires, more than ever, access to data located on multiple autonomous and heterogeneous data sources. The development of these novel information platforms, referred to as...
Mathematisch-naturwissenschaftlichen Fakultät, Wolfgang Kiess, Aus Künzelsau, Referent Prof, Dr. Martin Mauve, ...
Tag der mündlichen Prüfung: 03.06.2008 In wireless multihop networks (WMN), nodes cooperate to forward data packets for each other. This forwarding works without infrastructure, being a huge...
View Integration of Object Life-Cycles in Objectoriented Design (2007)
Object-oriented database schemas are often defined by several future users of the planned database, where each user defines a schema representing his/her view on the database; the complete database...
7 EVOLVING LOGICAL SPECIFICATION IN INFORMATION SYSTEMS (2007)
Stefan Conrad, Jaime Ramos, Gunter Saake, Cristina Sernadas
Abstract: Traditional logic-based specification approaches fix the structure and the dynamics of an object system at specification time. Information systems are applications with a very long...
Towards Agent-Oriented Specification of Information Systems (2007)
Stefan Conrad, Can Türker, Gunter Saake
Objects in information systems usually have a very long life-span. Therefore, it often happens that during the life of an object external requirements are changing, e.g. changes of laws. Such changes...
Prototyping Object Specications Using the CO-Nets Approach (2007)
Nasreddine Aoumeur, Stefan Conrad, Günter Saake
The CO-Nets approach, that we are developing, is an object oriented Petri net-based framework for specifying as well as prototyping---through graphical animation accompanied by a concurrent...
Work ow Descriptions in Engineering Applications (2007)
Work ow descriptions play a central role in formal specications of engineering applications. Due to dierent viewpoints, diverse work ow speci cations techniques have evolved in computer science and...
Prototyping Object Specications Using the CO-Nets Approach (2007)
Nasreddine Aoumeur, Stefan Conrad, Gunter Saake
The CO-Nets approach, that we are developing, is an object oriented Petri net-based framework for specifying as well as prototyping|through graphical animation accompanied by a concurrent computation...
SIGM AFDB: Overview of the Magdeburg Approach to Database Federations (2007)
Michael Hoding, Kerstin Schwarz, Stefan Conrad, Gunter Saake, Soren Balko, Andrea Diekmann, ...
LNCS, Springer-Verlag, 1999. Design Support for Database Federations? (2007)
Kerstin Schwarz, Ingo Schmitt, Can Turker, Michael Hoding, Eyk Hildebrandt, Soren Balko, ...
Abstract. Federated database systems provide a homogeneous interface to possibly heterogeneous local database systems. This homogeneous interface consists of a global schema which is the result of a...
Dealing with Uncertainties during the Data(base) Integration Process # (2007)
Evguenia Altareva, Stefan Conrad
Applying various data mining techniques to the task of integrating heterogeneous databases into one system leads to the necessity of dealing with uncertain information. The problem of integration is...
A Prolog Interpreter in Python (2007)
Carl Friedrich Bolz, Gutachter Prof, Dr. Michael Leuschel, Prof Dr, Stefan Conrad, ...
We provide a proof-of-concept for a new approach to flexible and portable implementation of programming languages. More precisely, we describe the implementation of a Prolog interpreter in RPython, a...
Mathematisch-naturwissenschaftlichen Fakultät, Cristian Pérez, Laborda Schwankhart, Referent Prof, Dr. Stefan Conrad, Tim Berners-lee
“[The Semantic Web] is about the data which currently is in relational databases, XML documents, spreadsheets, and proprietary format data files, and all of which would be useful to have access to...
Database to semantic web mapping using rdf query languages (2006)
Abstract. One of the main drawbacks of the Semantic Web is the lack of semantically rich data, since most of the information is still stored in relational databases. In this paper, we present an...
Integration of the ProB model checker into Eclipse (2006)
Softwaretechnik Und Programmiersprachen, Jens Marco Bendisposto, Gutachter Prof, Dr. Michael Leuschel, Prof Dr, Stefan Conrad, ...
Hiermit versichere ich, dass ich diese Bachelorarbeit selbstständig verfasst habe. Ich habe dazu keine anderen als die angegebenen Quellen und Hilfsmittel verwendet.
Relational.OWL - A Data and Schema Representation Format Based on OWL (2005)
Stefan Conrad, Cristian Pérez, Laborda Stefan Conrad
One of the research fields which has recently gained much scientific interest within the database community are Peer-to-Peer databases, where peers have the autonomy to decide whether to join or to...
Querying Relational Databases with RDQL (2005)
Most Semantic Web applications are still unable to query data stored in relational databases using their own built-in functionality. Hence, needing access to such data, they have to fall back on SQL...
Improving Integration Quality for Heterogeneous Data Sources (2004)
E. Altareva, Evgeniya Altareva, Referent Prof, Dr. Stefan Conrad, Korreferent Prof, Dr. Arndt Haeseler, ...
This work considers a problem of integrating heterogeneous semi--structured data sources with the purpose of estimating integration quality (IQ). During the integration of such data sources the IQ...
Dígame: A Vision of an Active Multidatabase (2004)
Christopher Popfinger, Stefan Conrad
Sharing information in loosely coupled enterprises or virtual corporations demands a flexible and dynamic architecture, suitable for their individual data policies. The aim of this paper is to...
Arnold Müller, Stefan Conrad, Ernst Kruijff
To provide an adequate user interface to the large amount of geometrical and alphanumerical date coupled to the geometries, the 3D interaction in the virtual environment is combined with 2D...
A Semantic Web based Identification Mechanism for Databases (2003)
In this paper we suggest the novel URI scheme db for identifying not only databases, but also their schema and data components like tables or columns. One of the features of this scheme is that it...
View Integration of Behavior in Object-oriented Databases (2001)
Günter Preuner, Stefan Conrad, Michael Schrefl
Database schemas are often not defined by a single person but by several future users of the database who define their possibly different views on the proposed database schema. These views are...
Temporal OCL: Meeting Specifications Demands for Business Components (2001)
Abstract. Compositional plug-and-play-like reuse of black box components requires sophisticated techniques to specify components, especially if we combine third party components, which are traded on...
Adding Conflict Resolution Features to a Query Language for Database Federations (2000)
Kai-Uwe Sattler, Stefan Conrad, Gunter Saake
A main problem of data integration is the treatment of conflicts caused by different modeling of realworld entities, different data models or simply by different representations of one and the same...
Adding Conflict Resolution Features to a Query Language for Database Federations (2000)
Kai-Uwe Sattler, Stefan Conrad, Gunter Saake
A main problem of data integration is the treatment of conflicts caused by different modeling of realworld entities, different data models or simply by different representations of one and the same...
Adding Conflict Resolution Features to a Query Language for Database Federations (2000)
Kai-Uwe Sattler, Stefan Conrad, Gunter Saake
A main problem of data integration is the treatment of conflicts caused by different modeling of realworld entities, different data models or simply by different representations of one and the same...
Conrad, Stefan, Saake, Gunter, Sattler, Kai-Uwe, Keim, Daniel A.
In vielen Anwendungsbereichen besteht die Aufgabe, Daten oder Informationen aus verschiedenen, zum Teil heterogenen Quellen zu kombinieren, zu verdichten und daraus Informationen einer neuen...
Adding Conflict Resolution Features to a Query Language for Database Federations (2000)
Kai-uwe Sattler, Stefan Conrad, Gunter Saake
Abstract. A main problem of data integration is the treatment of conflicts caused by different modeling of real-world entities, different data models or simply by different representations of one and...
Adding Conflict Resolution Features to a Query Language for Database Federations (2000)
Kai-uwe Sattler, Stefan Conrad, Gunter Saake
Abstract. A main problem of data integration is the treatment of conflicts caused by different modeling of real-world entities, different data models or simply by different representations of one and...
Consistency Management in Object-Oriented Databases (1999)
Hussien Oakasha, Stefan Conrad, Gunter Saake
. The paper presents concepts and ideas underlying an approach for consistency management in object oriented databases. In this approach constraints are structured as first class citizens and stored...
Considering Integrity Constraints During Federated Database Design (1998)
Stefan Conrad, Ingo Schmitt, Can Türker
. Correct transformations and integrations of schemata within the process of federated database design have to encompass existing local integrity constraints. Most of the proposed methods for schema...
Evolving Logical Specification in Information Systems (1998)
Stefan Conrad, Jaime Ramos, Gunter Saake, Cristina Sernadas
Traditional logic-based specification approaches fix the structure and the dynamics of an object system at specification time. Information systems are applications with a very long life-time....
Föderierte Datenbanksysteme : Konzepte der Datenintegration / (1997)
Magdeburg, Universiẗat, Habil.-Schr., 1997.
Myra Spiliopoulou, Stefan Conrad
Abstract. The autonomy of the participants in a database federation makes the maintenance of consistency on the shared data a hard problem. A constraint mechanism at the federation level is often...
Requirements for Agent-based Modeling of Federated Database Systems (Extended Abstract) (1997)
Can Türker, Gunter Saake, Stefan Conrad
) Can Turker Gunter Saake Stefan Conrad Institut fur Technische Informationssysteme Otto-von-Guericke-Universitat Magdeburg Postfach 4120, D--39016 Magdeburg E-mail:...
Extending Temporal Logic for Capturing Evolving Behaviour (1997)
. The known approaches to object specification based on firstorder temporal logic fail in capturing the often occurring need to change the dynamic behaviour of a system during lifetime of that...
Behandlung von Integritätsbedingungen bei Schemarestrukturierung und Schemaintegration (1997)
Stefan Conrad, Ingo Schmitt, Can Türker, Schemarestrukturierung Und Schemaintegration, Restrukturierung Von Schemata
che sehr unterschiedlich. Auch wenn zum Beispiel die Schemarestrukturierung als ein Spezialfall der Sichtableitung aufgefat werden kann, werden in diesen Bereichen doch zumeist unterschiedliche Ziele...
Modeling Database Federations in Terms of Evolving Agents (1997)
Can Türker, Gunter Saake, Stefan Conrad
For advanced information systems, the interoperation between heterogeneous database systems which autonomously manage their existing, independently developed databases is a fundamental issue. Thus,...
Towards an Agent-Oriented Framework for Specification of Information Systems (1997)
Stefan Conrad, Gunter Saake, Can Türker
Objects in information systems usually have a very long life-span. Therefore, it often happens that during the life of an object external requirements are changing, e.g. changes of laws. Such changes...
Schema Integration with Integrity Constraints (1997)
Stefan Conrad, Michael Höding, Gunter Saake, Ingo Schmitt, Can Türker
. In this paper we discuss the use and treatment of integrity constraints in the federated database design process. We consider different situations occurring frequently in the schema transformation...
Towards Maintaining Integrity of Federated Databases (1997)
Abstract Supporting integrity constraints is essential for database systems. In consequence, global integrity constraints must be dealt with by federated database systems. Although a lot of work has...
Using Active Mechanisms for Global Integrity Maintenance in Federated Database Systems (1996)
Federated database systems have special requirements w.r.t. integrity maintenance. For instance, it must be possible to express inter-database dependencies in an adequate language and the federated...
Specifying Evolving Temporal Behaviour (1996)
The usual approaches to object specification based on first-order temporal logic fail in capturing the often occurring need to change the dynamic behaviour of a system during lifetime of that system....
Using Active Mechanisms for Global Integrity Maintenance in Federated Database Systems (1996)
Federated database systems have special requirements w.r.t. integrity maintenance. For instance, it must be possible to express inter-database dependencies in an adequate language and the federated...
Integrity Constraints in Federated Database Design (1996)
Stefan Conrad, Michael Höding, Sven Janssen, Gunter Saake, Ingo Schmitt, Can Türker
In this paper we demonstrate the application of a methodology for federated database design. Federated database design includes the transformation of heterogeneous local schemata from the native data...
A Development Environment for an Object Specification Language (1995)
Martin Gogolla, Stefan Conrad, Grit Denker, Rudolf Herzig, Nikolaos Vlachantonis
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...
A Development Environment for an Object Specification Language (1995)
Martin Gogolla, Stefan Conrad, Grit Denker, Rudolf Herzig, Nikolaos Vlachantonis
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...
From Object Specification towards Agent Design (1995)
Gunter Saake, Stefan Conrad, Can Turker
Abstract. Nowadays, object specification technology is successfully used for modelling information systems. However, object-oriented modelling cannot cover all aspects (e.g. dynamic behaviour...
Active Integrity Maintenance in Federated Database Systems (1995)
We propose the active database paradigm as a suitable approach to realize global integrity maintenance in tightly coupled federated database systems. It has come to light that there is a need for...
Prototyping Object Specifications Using Active Database Systems (1995)
For prototyping and implementing specified systems, an operational semantics has to be provided for the used specification language. For the specification of information systems ECA-rules being an...
Object-Oriented Database Design: What is the Difference with Relational Database Design? (1995)
Gunter Saake, Stefan Conrad, Ingo Schmitt, Can Türker
Object-oriented database design is not only a simple extension of relational database design. By modelling structure as well as behaviour of real world entities as coherent units, object-oriented...
A Development Environment for an Object Specification Language (1995)
Martin Gogolla, Stefan Conrad, Grit Denker, Rudolf Herzig, Nikolaos Vlachantonis
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...
Safe Derivations in Object Hierarchies (1995)
Stefan Conrad, Martin Gogolla, Rudolf Herzig
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...
Safe Derivations in Object Hierarchies (1995)
Stefan Conrad, Martin Gogolla, Rudolf Herzig
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...
A Basic Calculus for Verifying Properties of Synchronously Interacting Objects (1994)
Abt Datenbanken, Stefan Conrad, Stefan Conrad, Informatik Abt Datenbanken
The present paper introduces a basic calculus for expressing and proving properties of synchronously interacting objects. The objects considered have dynamic behavior and are organized into object...
An Elementary Logic for Object Specification and Verification (1994)
Stefan Conrad, Hans-dieter Ehrich
In the present paper we sketch an elementary logic for specifying information systems as systems of dynamic objects. First, we informally present the ingredients which should be included in a logic...
Compositional description of object communities with TROLL light (1994)
Rudolf Herzig, Stefan Conrad, Martin Gogolla
. 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...
TROLL light: A Core Language for Specifying Objects (1992)
Stefan Conrad, Martin Gogolla, Rudolf Herzig
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....
An Annotated Bibliography on Object--Orientation and Deduction (1992)
This note tries to briefly survey research activities and results on the integration of object-- oriented concepts and deductive database languages. 1 Introduction There are several efforts creating...
An Annotated Bibliography on Object-Orientation and Deduction (1992)
This note tries to briefly survey research activities and results on the integration of object-- oriented concepts and deductive database languages. 1 Introduction There are several efforts creating...
Dealing With Integrity Constraints During Schema Integration (Extended Abstract)
Stefan Conrad, Ingo Schmitt, Can Türker
1 Introduction At the time being, a large number of methods have been proposed for schema integration, e.g., [SPD92, RPRG94, SS96a, SC97]. Surprisingly, most of them do not consider the integration...