Andreas Reuter

• Dr.-Ing.
• Chair at Heidelberg Laureate Forum Foundation

Grid computing has been the subject of many large national and international IT projects. However, not all goals of these projects have been achieved. In particular, the number of users lags behind the initial forecasts laid out by proponents of grid technologies. This underachievement may have led to claims that the grid concept as a whole is on i...

Proceedings of the 18th ECOOP Doctoral Symposium and PhD Students Workshop AITO unpublished is peer reviewed

The ConTract model has been developed to extend the scope of classical (ACID)transactions to long-running executions such as workflows. A particular important aspect of the ConTract model is its approach to concurrency control. It uses semantic rather than syntactic synchronization, which influences both the programming style of long-running applic...

In this article I will reflect on the writing of "Transaction Processing - Concepts and Techniques" (1), which appeared at Morgan Kaufmann Publishers in 1992. The process of writing had many aspects of a typical software project: In the end, the book was more than twice as thick as we had planned, it covered only ¾ of the material that we wanted to...

In this article I will reflect on the writing of "Transaction Processing -- Concepts and Techniques" [1], which appeared at Morgan Kaufmann Publishers in 1992. The process of writing had many aspects of a typical software project: In the end, the book was more than twice as thick as we had planned, it covered only 3/4 of the material that we wanted...

Concepts and Methods (Dimension 1)Applications (Dimension 2)Platforms (Dimension 3)

A system is dependable if you can trust it to work. This seems to a completely obvious, almost trivial definition. But the question of what it means for a system to “work” is influenced by the type of system and the perspective of the user — among other things. Depending on the function, reliability can be an important criterion, but in other cases...

The break out session discussed guaranteed properties during program execution. Using a workflow example application, we discussed several research topics that form part of the guaranteed properties, including declarative specifications, generation of workflow program, generation of invariant guards, automated failure analysis, automated repair, an...

Database technology has come a long way. Starting from systems that were just a little more flexible than low-level file systems, they have evolved into powerful programming and execution environments by embracing the ideas of data independence, non-procedural query languages, extensible type systems, automatic query optimization (including paralle...

Wenn ein Informatiker mit der Titelfrage (oder sonst einer Frage) konfrontiert wird, schaut er zunächst einmal im Internet nach, ob er bei den vielen Informatik-Fakultäten weltweit irgendwo eine passende Antwort findet. Ich habe das natürlich auch getan und — vielleicht liegt das an meiner mangelnden Virtuosität im Umgang mit dem neuen Medium — kei...

. Um sich auf dem Bildungsmarkt behaupten zu können, müssen Universitäten und Fachhochschulen ihre Stärken herausstellen und sich auf die neue Konkurrenz vorbereiten, fordert die Schrift, die von dem Expertenkreis „Hochschulentwicklung durch neue Medien“ der Bertelsmann Stiftung und der Heinz Nixdorf Stiftung erarbeitet wurde.

Svjatnyj V..4., GiHes E.-D., Zeitz M., ReuterA., Rothermel K. Simulation software for a distributed parallel simulation environmentfor dynamic systems. The structure of the simulation software for a distributed parallel simulation environment is proposed. The user interface and the simulation languages are described.

this paper, is characterized by three very simple insights:

During the last decade, all commercial database systems have included features for parallel processing into their products. This development has been driven by the fact that databases grow in size at considerable rates. According to the results of the 1998 `very large database contest' the world’s largest databases, which have reached a size of ove...

On April 23, 1993 a panel discussion was held at the IEEE International Conference on Data Engineering in Vienna, Austria, at which five members of the data base research community discussed future research topics in the DBMS area. This paper summarizes the discussion which took place. The panel followed a similar format to that used at Laguna Beac...

This paper provides a progress report on the development of softwaretools in the Process Handbook project currently underway at the MIT Center for Coordination Science. We begin with a brief overview of the project as a whole. Then we focus on softwaretools emphasizing aspects that relate to work#ow control. Finally, we conclude with a brief descri...

Deutschland nimmt bei der Grundlagenforschung nach wie vor einen internationalen Spitzenplatz ein. Die Umsetzung der Forschungsresultate in Produkte aber leisten andere Länder effizienter und vor allem schneller als wir. Das hat vielfältige Ursachen, aber einige davon sind auch im wechselseitigen Selbstverständnis der Forschungseinrichtungen einers...

For the simulation of technological and natural processes in specific application domains, efficient calculation software solving differential equation systems on grid-based computational models is available, especially in the area of computer-aided engineering (CAE). To handle a so-called `multiphysics' problem, for example the fluid flow and meta...

Without Abstract

To meet the correctness requirements of mission-critical processes workflow systems have to commit guarantees regarding their behavior in case of failures and concurrency. The ConTract model is a conceptual framework for the reliable execution of long-lived computations in a distributed environment including workflows. This paper focuses on the asp...

The performance of object access can be drastically improved by efficient object prefetch. In this paper we present a new object prefetch policy, Selective Eager Object Fetch(SEOF) which prefetches objects only from selected candidate pages without using ...

The example of what formal correctness of concurrent execution in a workflow environment could mean demonstrates at least two things: Solutions that work well in traditional settings with short-lived units of computation cannot simply be carried over to that problem domain. Second, there is no unique, general correctness criterion. It much depends...

All database vendors have incorporated parallel features into their products. They had to do this for two reason: First, given applications can be run on ever larger databases with throughput increasing proportionally, but without affecting response times of interactive queries; this is called scaleup. Second, parallelism should help in reducing th...

this paper, (D1,D2,D3) was (type-of-business, type-of-part, state). Once most of the business types had been sold most of the part types in most of the states, this would be the case. At this point, very few insertions in I would be made, and consequently very few I-leaves would be split. 3.2 Our Proposal

this document is as follows: Section 2 describes the GRIDS computation model in full detail. Reference information on the files forming a complete GRIDS program and the GRIDS language constructs used in these files is contained in section 2. Section 3 explains the commands to preprocess and run a GRIDS program. As a part of the GRIDS project, sever...

Zugl.: Erlangen, Nürnberg, Universiẗat, Diss.

Bei diesem Streitgespräch kommt mir die interessante Position zu, begründen zu müssen, warum es neben Fahrrädern auch noch Autos, Flugzeuge, Eisenbahnen und Schiffe geben muß. Da diese Notwendigkeit schon in der Metapher nicht für jeden einsichtig sein mag, will ich mein Bestes tun, einige plausible Gründe anzuführen.

Die Bearbeitung raumbezogener Daten zwecks Darstellung in Landkarten wird zunehmend mit Computerunterstützung durchgeführt. Für den Prozeß der kartographischen Generalisierung, in dem die darzustellenden Gegebenheiten aufgrund von Platzmangel in der Darstellung vereinfacht bzw. modifiziert werden, existieren noch keine Verfahren, die den vielfältig...

Deutschland nimmt bei der Grundlagenforschung nach wie vor einen internationalen Spitzenplatz ein. Die Umsetzung der Forschungsresultate in Produkte aber leisten andere Länder effizienter und vor allem schneller als wir. Das hat vielfältige Ursachen, aber einige davon sind auch im wechselseitigen Selbstverständnis der Forschungseinrichtungen einers...

This paper considers the use of transaction processing systems in manufacturing applications. It is part of the ConTract project at Stuttgart University, which explores techniques to extend transaction technology into areas of long-lived, interacting applications. We will focus on two aspects: First, we will describe a transaction-oriented invocati...

Das in diesem Aufsatz beschriebene ConTract-Modell und seine prototypische Implementierung APRICOTS entstanden als Ergebnis eines Teilprojektes im Schwerpunktprogramm „Objektbanken für Experten“. Das Teilprojekt hatte die Aufgabe, Transaktionsmechanismen für die funktionell erweiterten Datenbanksysteme zu entwickeln, die mit dem Arbeitstitel „Objek...

The ConTract model, In: A. K. Elmagarmid (ed.): Transaction Models for Advanced Applications. Morgan Kaufmann Publishers, 1992

The Mannheim Supercomputer Seminar 1991 had one of its highlights in the Panel Discussion covering “Supercomputing 1995 and beyond”. Above named reputed personalities of leading supercomputer manufacturers participated in this discussion as well as Prof. Andreas Reuter from the “Institut für Parallele und Verteilte Höchstleistungsrechner”, Universi...

The talk starts with the observation that there often is a huge discrepancy between the claimed peak performance of a system and the actual performance experienced by the average user of that system running his/her program. The two figures can be two orders of magnitude apart for classic vector-oriented multi-processors, and the chances for that ha...

It has been demonstrated that future data management services will require a large number of both functional and structural extensions to current database systems. While these enhancements in themselves pose a variety of interesting problems, the focus of this paper has been to determine how the resulting reliability and performance requirements ca...

A range of approaches to integrating rule-based Artificial Intelligence (AI) systems and Database Management Systems are classified according to the degree of compilation that is performed by the AI system. This interpreted—compiled ...

This Lecture Notes volume is based on the "International Workshop on High Performance Transaction Systems" held in the Asilomar Conference Center, September 28-30, 1987. Many of the problems identified during the workshop are liable to determine the future development of transaction systems and distributed high performance systems in general for ma...

Presents a concept that permits long activities to be broken into several steps using short transactions. The scheme maintains the consistency of the data and the correct termination of the transaction-set is guaranteed. Invariant data or program structures can be passed to subsequent decision points, permitting an application designer to specify t...

Though in general, current database systems adequately support application development and operation for online transaction processing (OLTP), increasing complexity of applications and throughput requirements reveal a number of weaknesses with respect to the data model and implementation techniques used. By presenting the experiences gained from a...

Though in general, current database systems adequately support application development and operation for online transaction processing (OLTP), increasing complexity of applications and throughput requirements reveal a number of weaknesses with respect to the data model and implementation techniques used. By presenting the experiences gained from a...

Views are an indispensable mechanism for providing flexible database access in a workstation environment. On the other hand, views created from more than one base relation have complex and in some cases contradicting update semantics. In this paper we suggest to distinguish between object types as the units for data manipulation and views as the da...

Dieser Übersichtsaufsatz richtet sich vornehmlich an Informatiker und Informatik-Anwender, die nicht über spezifische Datenbank-Kenntnisse verfügen. Er zeichnet zunächst die Entwicklung der Technik verteilter Datenbanksysteme nach und resümiert dann den gegenwärtigen Entwicklungsstand, wie er sich vor allem in den jetzt auf den Markt kommenden Prod...

Die rasche Verfügbarkeit immer billigerer, leistungsfähigerer und zuverlässigerer Rechnertechnologien führt — neben vielem anderen — auch zum Aufbau weiträumig verteilter Kontroll- und Meßsysteme etwa im Bereich der Schadstoffüberwachung in Boden, Wasser und Luft, der Klimaforschung, der Geologie, aber auch bei der Verkehrskontrolle und vielen ande...

Without Abstract

Das Forschungsprojekt PROSPECT (PRocessor Organizations Supporting Parallel Execution in Complex Transactions) hat das Ziel, die Möglichkeiten zur Unterstützung sog. komplexer DB-Transaktionen durch Hard-und Software-Architekturen zu untersuchen, welche die parallele Abarbeitung von Teilschritten innerhalb einer solchen Transaktion in effizienter W...

Durch die zunehmende Verbreitung von PCs stellt sich die Frage, wie verteilte Verarbeitungsformen in bislang zentralisierte Anwendungen integriert werden können. An einem Beispiel wird gezeigt, daß Lösungskonzepte, wie sie für DDBMS, Workstation-DBMS u. ä. entwickelt worden sind, nicht unmittelbar übernommen werden können. Die Gründe hierfür sind i...

Expert systems are put to use in a rapidly increasing number of different applications. Consequently, they have to meet increasing demands in terms of complexity of the problem structures, and in terms of the number of rules and facts involved in the decision process. Managing large set of facts efficiently is the key purpose of database systems, w...

Ausgehend von einer Zusammenstellung der typischen Anforderungen in einer Reihe nicht-kommerzieller Anwendungsklassen wie CAD, Büroautomatisierung usw. wird zunächst dargestellt, inwiefern die existierenden, konventionellen Datenbank-Verwaltungssysteme zur Datenhaltung in solchen Bereichen nur schlecht oder gar nicht geeignet sind. Daraus wird eine...

Various logging and recovery techniques for centralized transaction-oriented database systems under performance aspects are described and discussed. The classification of functional principles that has been developed in a companion paper is used as a terminological basis. In the main sections, a set of analytic models is introduced and evaluated in...

This paper describes the concepts and implementation of a design aid for the internal schema of an existing CODASYL-like database system. It allows for tailoring the storage structure level to a given logical schema and a specified workload. According to the 1978 CODASYL report, our DBMS provides two levels of schema declaration, the DDL-level for...

A terminological framework is provided for describing different transaction-oriented recovery schemes for database systems in a conceptual rather than an implementation-dependent way. By introducing the terms materialized database, propagation strategy, and checkpoint, we obtain a means for classifying arbitrary implementations from a unified viewp...

If file replication is used as a means of improving file availability problems of mutual consistency arise when the network which connects copies is subject to partitioning. A method of detecting inconsistencies is presented and the problems associated ...

In many large database applications there are certain elements mostly containing aggregate information, which are very frequently referred to (read and modified) by many transactions. If access to such fields has to obey to conventional two-phase lock protocols (1,2), transactions will be serialized in front of these "hot spots", i.e. the degree of...