The paper MV-IDX: Multi-Version Index in Action by Robert Gottstein, Rohit Goyal, Ilia Petrov, Sergey Hardock and Alejandro Buchmann has been accepted for publication at the 16. Fachtagung "Datenbanksysteme für Business, Technologie und Web" (BTW) der Gesellschaft für Informatik (GI), Hamburg, Germany.

The paper "MV-IDX: Indexing in Multi-Version Databases" by Robert Gottstein, Rohit Goyal, Sergej Hardock, Ilia Petrov and Alejandro Buchmann has been accepted for publication at the "18th International Database Engineering &; Applications Symposium" (IDEAS 2014), held in Porto, Portugal on July 7th-9th, 2014.

14.02.2014

23.09.2013

The oral exam schedule is available and has been updated: Exam Schedule.

20.03.2013

The oral exam schedule is available and has been updated: Exam Schedule.

05.03.2013

The oral exams with Prof. Buchmann will take place between April, 17th, and May, 10th. A detailed schedule will be published by the end of March.

22.01.2013

The DVS members Stefan Appel, Tobias Freudenreich, Sebastian Frischbier, and Christian Seeger have been admitted to Software Campus. In collaboration with partners from industry, Software Campus participants receive funding for innovative IT projects and benefit from an individually tailored training curriculum with outstanding academics and managers.

10.01.2013

The paper "Eventlets: Components for the Integration of Event Streams with SOA" (PDF) by Stefan Appel, Sebastian Frischbier, Tobias Freudenreich, and Alejandro Buchmann received the Best Paper Award at the 2012 IEEE International Conference on Service-Oriented Computing and Applications (SOCA) held in Taipei, Taiwan, in December 2012.

The article "All-Weather Transport Essentials" by Christof Leng, Wesley W. Terpstra, Max Lehn, Robert Rehner and Alejandro Buchmann has been published in the special issue on "Future Internet Protocols" of the IEEE Internet Computing magazine.

DFG has granted the new collaborative research center (Sonderforschungsbereich, SFB) 1053: "MAKI – Multi-Mechanismen-Adaption für das künftige Internet" (www.maki.tu-darmstadt.de, see also TU Darmstadt's news entry). DVS will be working on two projects in MAKI.

The paper "Aspects of Append-Based Database Storage Management on Flash Memories" by Robert Gottstein, Ilia Petrov, and Alejandro Buchmann has been accepted for publication at the Fifth International Conference on Advances in Databases, Knowledge, and Data Applications (DBDKA).

The paper "Generation of Synthetic Workloads for Peer-to-Peer Gaming Benchmarks" by Tonio Triebel (University of Mannheim), Max Lehn (DVS), Robert Rehner (DVS), Benjamin Guthier (University of Mannheim), Stephan Kopf (University of Mannheim), Wolfgang Effelsberg (University of Mannheim) has been accepted for publication at the 11th Annual Workshop on Network and Systems Support for Games (NetGames 2012).

The paper "Eventlets: Components for the Integration of Event Streams with SOA" by Stefan Appel, Sebastian Frischbier, Tobias Freudenreich, and Alejandro Buchmann has been accepted for publication at the IEEE International Conference on Service-Oriented Computing and Applications (SOCA).

We have new offerings for both jobs and theses. For details, please visit Jobs and Theses

The poster ASIA: Application-Specific Integrated Aggregation for Publish/Subscribe Middleware by Sebastian Frischbier (DVS), Alessandro Margara (Vrije Universiteit Amsterdam), Tobias Freudenreich (DVS), Patrick Eugster (Purdue University), David Eyers (University of Otago), and Peter Pietzuch (Imperial College London) has been accepted to the Posters and Demo Track of Middleware 2012. Further information about the ongoing ASIA project can be found here.

The oral exams with Prof. Buchmann took place October 9.

We are glad to announce the launch of the second TUDμNet site: TIZ. The acronym stands for the german Technologie und Innovationszentrum, and is the building where the laboratory of the DFG-funded Research Training Group GRK 1362 is located. Spanning a surface of ~180 square meters, the TIZ deployment includes 60 TelosB sensor nodes equipped with the standard SHT11 sensors (light, humidity, temperature).

Similarly to other deployments (e.g., EmStar [1]), all nodes are mounted on the ceiling of the various areas of the GKmM lab. While 3 of these are typical office space, the largest is a disaster scenario following RoboCup Rescue's urban search and rescue [2] arena assembly guide. This allows a more realistic evaluation of the integration of sensor networks with mobile robots.

In the next days we will be running some statistics to evaluate the performance of the testbed services (reprogramming and logging), though researchers can go ahead and begin using the new zone when scheduling a job.

A short clip showcasing the deployment can be found in YouTube.

[1] "Em*: a Software Environment for Developing and Deploying Wireless Sensor Networks", Girod et al.

[2] RoboCup Rescue site.

Our paper Diagnosing the Weakest Link in WSN Testbeds: A Reliability and Cost Analysis of the USB Backchannel by P. Guerrero, I. Gurov, A. Buchmann and K. Van Laerhoven has been accepted at the 7th IEEE International Workshop on Practical Issues in Building Sensor Network Applications 2012 for publication in its proceedings as a regular paper. Here we described our work in building reliable USB backchannels for sensor network testbeds, which was vital in the realization of the new sites of TUDμNet.

The paper Making Cost-Based Query Optimization Asymmetry Aware by Daniel Bausch, Dr.-Ing. Ilia Petrov, and Prof. Alejandro Buchmann has been accepted at the DaMoN (Data Management on New Hardware) workshop 2012. The work will be presented at the workshop colocated with SIGMOD/PODS on 21. May 2012.

The paper Emergence as Competitive Advantage - Engineering Tomorrow's Enterprise Software Systems by Sebastian Frischbier (DVS), Michael Gesmann (Software AG), Dirk Mayer (Software AG), Andreas Roth (SAP), and Christian Webel (Fraunhofer IESE) has been accepted to the 14th International Conference on Enterprise Information Systems (ICEIS'12).

The paper ACTrESS - Automatic Context Transformations in Event-based Software Systems by Tobias Freudenreich, Stefan Appel, Sebastian Frischbier, and Alejandro Buchmann has been accepted to this year's conference on Distributed Event-Based Systems.

We are glad to announce completion of the migration of the TUDμNet testbed federation to a new home, a Xeon E3. This will enable us to further enhance the services offered.
What's been keeping us busy in the last weeks:

• presented the overall system architecture at EWSN in Trento, Italy,
• increased the system's reliability: TUDμNet now features an improved USB infrastructure that enables much less un-programmable nodes, as well as much lower overall system downtime,
• extended the system to handle different sensor node types,
• addition of Z1 nodes to the testbed (first testbed to have these!),
• among other finer improvements.

The roadmap for the upcoming weeks includes scaling the network up at the second and third floors of the Piloty building, launching the second site at the TIZ building (which will include an impressive array of 51 gas sensors), and the connection of the third site (already deployed) at the surPLUShome. Stay tuned!

The oral exams with Prof. Buchmann and Ulrich Gräf will take place between March 22 and March 30.
Detailed Schedule

For questions regarding the exam schedule contact tiedem@dvs.tu-...

The paper Living in the Present: On-the-fly Information Processing in Scalable Web Architectures by David Eyers, Tobias Freudenreich, Alessandro Margara, Sebastian Frischbier, Peter Pietzuch and Patrick Eugster has been accepted at the 2nd International Workshop on Cloud Computing Platforms (CloudCP). CloudCP is held in conjunction with EuroSys 2012 (Bern, Switzerland).

The SPEC Research Group has awarded DVS alumnus Dr.-Ing. Kai Sachs with the SPEC Distinguished Dissertation Award 2011 for his doctoral dissertation titled "Performance Modeling and Benchmarking of Event-Based Systems".

The SPEC Distinguished Dissertation Award was established in 2011 to recognize outstanding dissertations within the scope of the SPEC Research Group in terms of scientific originality, scientific significance, practical relevance, impact, and quality of the presentation.

The Best Paper Award of the International Conference on Body Area Networks is granted to Christian Seeger, Alejandro Buchmann, and Kristof Van Laerhoven for the paper titled myHealthAssistant: A Phone-based Body Sensor Network that Captures the Wearer's Exercises throughout the Day.
 

Please visit the myHealthAssistant webpage for more information.

Die aktuellen Prüfungstermine hängen aus.
Bitte notieren, dass die Termine vom Mittwoch, 12.10, auf Freitag, den 14.10 verlegt wurden.

Title: "Handling Events in a Clinical Environment"

Time: Tuesday September 27th 2011, 2:00 pm

Location: S202 / A102
 

Abstract: In this talk, we present an approach for contextualizing an event-based decision support system for scheduling patient assessments in a hospital. Through observations of a specific workflow in a Norwegian University Hospital, we found that the clinical environment offers a number of challenges that seem under-addressed in current event-related literature.

For example: To cope with unexpected delays, patient coordinators often pursue a worst case scenario when scheduling patient assessments, leading to an underutilization of human resources and equipment when the procedure went without complications. We present a context-based decision support system for patient planning that helps the patient coordinator with taking well-informed rescheduling decisions and anticipating changes in other patients' schedules. The system uses information and events produced by medical equipment. As these events can be nondeterministic, we demonstrate how our domain specific context model can be used to contextualize events to enhance their quality and ascertain their meaning.

We are currently implementing the system and have already found that traditional approaches do not fit our perspective. Reasons for this will be given during the talk.

The talk will mainly be about representing a "version" of the real world based digital information which was not meant for the purpose that it is used for. An explanation by use of a real life use case (see above) from a hospital that indicate the need for a notion of quality, both event quality and information quality will be addressed.
 

Short Bio: After finishing his B.Eng in The Netherlands, Leendert Wienhofen started working for CognIT a.s in Oslo as a knowledge engineer in 2000. He has mostly been working on EU research projects with a focus on a combination of ontologies, semantic web related technology, mobile platforms and business processes. In 2006, he started working for SINTEF ICT, Scandinavia's largest independent research institute and continued working on projects mostly related to mobile, context aware technology. In 2009 he started working on a PhD at NTNU with the main research focus on quality in event processing technology applied in hospitals. Getting the right information to the right person at the right time has always been one of the main topics in his work
 

Organizers: Prof. A. Buchmann, Sebastian Frischbier

We are presenting a demo and a poster on this year's ACM SIGCOMM conference in Toronto, Canada. The demo An Online Gaming Testbed for Peer-to-Peer Architectures by Max Lehn, Christof Leng, Robert Rehner, Tonio Triebel, and Alejandro Buchmann shows the current state of our P2P online gaming testbed with the game Planet PI4. The poster Designing a Testbed for Large-scale Distributed Systems by Christof Leng, Max Lehn, Robert Rehner, Alejandro Buchmann discusses state-of-the-art techniques for the development and evaluation of distributed applications.

On The Performance Of Database Query Processing Algorithms On Flash Solid State Disks.

Daniel Bausch, Ilia Petrov, Alejandro Buchmann
Sixth International Workshop on Flexible Database and Information System Technology (FlexDBIST). September, 2011.

Ensuring the confidentiality and integrity of data in distributed healthcare or financial applications is challenging. Developers may introduce unintended or deliberate security flaws in different parts of an application, which may lead to the disclosure of sensitive data. While access control mechanisms and source code auditing are used in practice to avoid security flaws, security violations are nevertheless a frequent occurrence.

Instead of avoiding all security flaws, I introduce our work on providing a "safety net" to distributed applications that prevents sensitive data disclosure from happening. Our approach is to use information flow control (IFC) to track the flow of data through a complex, heterogeneous distributed application and constrain undesirable flows that could violate data protection policy. I describe our DEFCon middleware that applies the IFC model to event-based systems in Java, after adding support for strong isolation between objects to the Java runtime. In addition, I present our recent work on PHP Aspis, which uses IFC to protect PHP web applications against injection vulnerabilities.

Page Size Selection for OLTP Databases on SSD RAID Storage.

Ilia Petrov, Robert Gottstein, Todor Ivanov, Daniel Bausch, Alejandro Buchmann
In Journal of Information and Data Management,Vol.2,No 1 (2011)

Abstract:

Scalability is a fundamental problem in the development of computer games and massively multiplayer online games (MMOs). Players always demand more --- more polygons, more physics particles, more interesting AI behavior, more monsters, more simultaneous players and interactions, and larger virtual worlds.

Most game developers think of databases as persistence solutions, designed to store and read game state. But the advantages of database systems go way beyond persistence. Database research has dealt with the question of efficiently processing declarative languages, and the resulting research questions have touched many areas of computer science.

In this talk, I will show how the idea of declarative processing from databases can be applied to computer games and simulations. I will then discuss how we can use ideas from optimistic concurrency control to scale interactions between players in MMOs, and I will conclude by describing how we can use these techniques to build elastic transaction processing infrastructure for the cloud.

About Johannes Gehrke:

Johannes Gehrke is a Professor in the Department of Computer Science at Cornell University. Johannes' research interests are in the areas of database systems, data mining, data privacy, and applications of database and data mining technology to marketing and the sciences. Johannes has received a National Science Foundation Career Award, an Arthur P. Sloan Fellowship, an IBM Faculty Award, the Cornell College of Engineering James and Mary Tien Excellence in Teaching Award, the Cornell University Provost's Award for Distinguished Scholarship, a Humboldt Research Award, and the 2011 IEEE Computer Society Technical Achievement Award. He is the author of numerous publications on data mining and database systems, and he co-authored the undergraduate textbook Database Management Systems (McGrawHill (2002), currently in its third edition), used at universities all over the world. Johannes is also an Adjunct Associate Professor at the University of Tromsø in Norway.

Johannes was co-Chair of the 2003 ACM SIGKDD Cup, Program co-Chair of the 2004 ACM International Conference on Knowledge Discovery and Data Mining (KDD 2004), Program Chair of the 33rd International Conference on Very Large Data Bases (VLDB 2007), and Program co-Chair of the 28th IEEE International Conference on Data Engineering (ICDE 2012). From 2007 to 2008, he was Chief Scientist at FAST, A Microsoft Subsidiary. At Cornell, Johannes teaches in the Department of Computer Science, the Information Science Program, and in the Johnson Graduate School of Management. He has extensive industry experience as technical advisor and consultant.

Johannes Gehrke's web page.

The course covers the foundations of Business Intelligence and Data Warehousing from architectural, algorithmic and practical perspective. In addition it covers new trends such as Data Warehouse Appliances, Cloud Analytics, Column Stores and the use of flash memory. The course replaces its predecessor-Data Warehousing.

The lecture includes a hands-on practical exercise, in which we shall demonstrate different systems and techniques.

More information

Many of today's software systems rely on predictable and stable information flows. Due to the digitalization of the world, these flows become increasingly more complex and dynamic. Thus, tomorrow's software systems have to become more distributed and reactive. Those Distributed Reactive Software Systems (DReSS) are best realized with event-based systems.

In our new lecture we discuss state of the art research and provide hands-on experience in implementing a ready-to-use event-based system which will process real-time event data from our sensors.

Further information