Dipl.-Inform. Stephan Kottler

Address

Arbeitsbereich für Paralleles Rechnen
Wilhelm-Schickard Institut für Informatik
Sand 14, D-72076 Tübingen, Deutschland

Contact Information

Email:	stephan.kottlerunituebingen.de
Phone:	+49-7071-2970480
Room:	C108
Office hours:	by appointment

---

Research Interests | Teaching | Publications | Software | Education

---

Research Interests

• SAT Solving
• Algorithm Engineering
• NP-hard Problems in Practice
• Algorithms and Data Structures
• Visualisation of Graphs

Teaching

• Betreuung eines Programmierprojekts des Softwarepraktikums (SS 09)
• Übungen zur Vorlesung Algorithmen und Komplexität I (WS 08/09)
• Seminar: Wissenschaftliches Arbeiten in der Algorithmik (WS 08/09)
• Übungen zur Vorlesung Randomisierte Algorithmen (SS 08)
• Betreuung eines Programmierprojekts des Softwarepraktikums (SS 08)
• Übungen zur Vorlesung Paralleles Rechnen (WS 07/08)

Publications

• Michael Kaufmann, Stephan Kottler: Proving or Disproving Planar Straight-Line Embeddability onto given Rectangles, Proc. of the 17th International Symposium on Graph Drawing (GD '09), (To appear)
  BibTex -- Abstract
• Benjamin Albrecht, Philip Effinger, Markus Held, Michael Kaufmann, Stephan Kottler: Visualization of Complex BPEL Models, Proc. of the 17th International Symposium on Graph Drawing (GD '09), (To appear)
  BibTex -- Abstract
• Stephan Kottler, Michael Kaufmann, Carsten Sinz: Computation of Renameable Horn Backdoors, Theory and Applications of Satisfiability Testing - SAT 2008, 2008
  BibTex -- Abstract
• Stephan Kottler, Michael Kaufmann, Carsten Sinz: A New Bound for an NP-Hard Subclass of 3-SAT Using Backdoors, Theory and Applications of Satisfiability Testing - SAT 2008, 2008
  BibTex -- Abstract
• Katharina A. Lehmann, Stephan Kottler: Visualizing Large and Complex Networks, Proceedings of the 14th International Symposium on Graph Drawing (GD'06), 2007
  BibTex -- Abstract

Misc

• Stephan Kottler Description of the SApperloT solvers for the SAT-Competition 2009 , SAT 2009, Wales
  
• Stephan Kottler, Michael Kaufmann, Carsten Sinz Poster: A New Bound for a subclass of 3-SAT using Backdoors , Poster @ SAT 2008, China
  
• Stephan Kottler, Michael Kaufmann, Carsten Sinz Poster: Computation of RHorn Backdoors , Poster @ SAT 2008, China
  
• Stephan Kottler Backdoors in SAT-Instanzen, Wilhelm-Schickard-Institut, Universität Tübingen, Diplomarbeit, 2007
  

Software

• Source code of SApperloT-base for Linux as submitted to the SAT-competition 2009. Note that this version is a bit more verbose than the submitted one. More information about SApperloT can be found here.
• SatIn is a visualisation tool for SAT instances (Sat Insight) written in Java on top of the yFiles library. It allows for depicting different kinds of graphs that can be gained from SAT instances in conjunctive normal form. The layout of a graph can be chosen from a set of available automated layouts and, moreover, can be modiefied manually. Selecting an element in one graphical representation automatically highlights the according elements in all other graphical representations. Execute it with the command: java -jar SatIn.jar.
• The tool GridFit can be used to prove or disprove whether or not a plane graph can be embedded onto a given rectangle/grid. The embedding assumes edges to be drawn straight-line and without crossings. Internally GridFit encodes this problem into SAT and uses a modified version of SApperloT to solve the transformed problem. Source code for Linux of a preliminary version of GridFit is available for download. Just invoke 'make' in the top level directory and execute 'GridFit' to see the options. GridFit can be used for small graphs but it might get into trouble with larger graphs!
If you have questions or any kind of feedback to the above software please don't hesitate to contact me!

Education

• 10/2007: Started as a PhD student at the Wilhelm-Schickard-Institut für Informatik, Tübingen, Germany in the Paralleles Rechnen group headed by Michael Kaufmann.
• 09/2007: Diploma in computer science
• 10/2004 - 07/2005: Erasmus exchange at the University of Malta  
• 10/2001: Started studies in computer science at the Eberhardt-Karls-Universität, Tübingen, Germany