Department of Informatics

Department Seminar 2011

Fall 2011

November 17

Marc Rehmsmeier (The Computational Biology Unit (CBU))

Title: It's not the size that matters but what you do with it. DNA sequence principles in the era of genome-wide datasets

Abstract: Genome-wide data is being generated at an alarming rate. But what does it all mean? In this talk I will ponder on how DNA sequence principles can make sense of this evergrowing mass.

About the speaker: Marc Rehmsmeier is a Group Leader and Senior Scientist at the Computational Biology Unit (CBU) within Uni Computing.

NB: Food and drinks will be served half an hour before the seminar outside the large auditorium.


November 3

Professor Michael Löwe (Fachhochschule für die Wirtschaft Hannover )

Tittel: Rule-based Refactoring of Software Systems - A Graph Transformation Approach


Agile and test-driven software development needs powerful refactoring support, since changes to the system under development are often. (For example, design patterns are introduced on demand not in advance.) For the time being, the agile method and software refactoring work quite good as long as the system being developed is not in operation. The situation is different for productive real-life systems that possess huge databases. Changing the structure of the software (i. e. the system's model) requires corresponding changes to the data. Here, we do not find satisfactory refactoring support that automatically induces (on-demand) data migrations from model refactorings. To some extent, the necessary theory for a suitable tool support is missing yet.

In this talk, we present a (formal) framework that is able to describe model refactorings together with induced data migrations. We demonstrate the practical power of the model by some typical refactoring examples like “interface extraction”, “pulling-up of associations”, “proxy insertion”, or “composite preparation”. Within the framework, theoretical results can be proven which are needed as a solid basis for practical tool support. In this talk, we discuss sequential composition of refactorings – a necessary prerequisite for practical versioning support of models and data.

For the time being, the framework is not rule-based. Refactorings are relations between complete models. This is not appropriate for practical purposes. In this talk, we show that the current approaches to (algebraic) graph transformation cannot be applied here: Refactoring rules do not delete and insert model artefacts, they copy and merge them. We present first ideas, how the mechanisms and the theory of the algebraic approaches to graph transformations can be generalized in order to be applicable in the presented refactoring framework.

About the speaker:  Prof. Dr. Michael Löwe is the head of the Computer Science department at the University of Applied Science Hannover in Germany (http://www.fhdw-hannover.de/en/node/1). His main research interests are the foundation and the practical application of Algebraic Specifications and Graph Transformations.


September 16

Professor Moshe Vardi (Rice University, Houston):

Tittel: And Logic Begat Computer Science: When Giants Roamed the Earth

Abstract: During the past fifty years there has been extensive, continuous, and growing interaction between logic and computer science. In fact, logic has been called "the calculus of computer science". The argument is that logic plays a fundamental role in computer science, similar to that played by calculus in the physical sciences and traditional engineering disciplines.  Indeed, logic plays an important role in areas of computer science as disparate as architecture (logic gates), software engineering (specification and verification), programming languages (semantics, logic programming), databases (relational algebra and SQL), artificial intelligence (automated theorem proving), algorithms (complexity and expressiveness), and theory of computation (general notions of computability). This non-technical talk will provide an overview of the unusual effectiveness of logic in computer science by surveying the history of logic in computer science, going back all the way to Aristotle and Euclid, and showing how logic actually gave rise to computer science.

About the speaker: Moshe Y. Vardi is Karen Ostrum George Professor in Computational Engineering and Director of the Ken Kennedy Institute for Information Technology.
His interests focus on applications of logic to computer science and on teaching logic across the curriculum. He is a member of the American Academy of Arts and Sciences and recipient of many prestigious international prizes such as the Gödel Prize in 2000, the Kannelakis Award in 2005, and the Blaise Pascal Medal 2008. Last but not least he is Editor-in-Chief of the Communications of the ACM.

The presentation can be found here.