Today I gave the final completion presentation for my diploma thesis. The talk showcased a selection of results published in the thesis. Results and experiments are only sketched, as all further detailed information can be found in the thesis PDF itself.

The talk contains side-by-side comparison plots of feature enhancements made to ns-3 and verifications thereof using ns-2. Furthermore, the EDCA extensions implemented in ns-3 are tested against analytically calculated reference values. In the end, a speed test comparison is done between ns-2 and ns-3, which uses the implemented classes to run an experiment scenario identically on both simulators.

The slides are available as PDFs in following two variants:

Here the table of contents:

1. Thesis Objectives
2. Enhancements
   1. Propagation Loss Models
   2. Reception Criteria
   3. Frame Capture Effect
   4. EDCA Implementation
3. Speed Comparison
4. Conclusion
5. Appendix
   1. Enlarged Plots and Figures
      1. Propagation Loss Models
      2. Reception Criteria
      3. Frame Capture Effect
      4. EDCA Implementation

For the last three months I have been working intensely on my diploma thesis. The thesis will be about 802.11 enhancements and EDCA QoS extensions in the new network simulator ns-3.

Today I gave my halftime presentation about the current status of my efforts. The talk is composed of a short introduction into ns-3, followed by a detailed discussion of WLAN packet reception criteria and finishes with a review of DCF and how EDCA extends it.

Be warned: many slides are not all self-explanatory and therefore less suitable as a casual introduction into the topics. They are slides meant for presentation.

The slides are available as PDFs in following three variants:

Here the table of contents:

1. ns-3 Basics
   1. Introduction
   2. Showcase: Design Patterns
   3. Current State
2. Wifi in ns-3
   1. State of 802.11
   2. PHY Layer
   3. Signals, Noise and Interference
   4. Short Recapitulation of DCF
   5. QoS with EDCA
3. Conclusion

Following up on the technical report, today Dimitar and myself gave a 70min presentation on Robert Gallager's Minimum Delay Routing Algorithm Using Distributed Computation. It finished my work for the NetFundamentals seminar, which was organized by Decentralized Systems and Network Services Research Group at the Institute of Telematics. The seminar was very profound and extensively dug into the mathematics of six fundamental networking papers. Besides that it was great fun and opened some new horizons.

Our presentation can be downloaded as PDF (553 KB), with two slides per page or even with four per page.

Furthermore our listeners were given an equation sheet (139 KB) to aid them in following the many formulas.

At the University of Karlsruhe it is common to give a concluding talk after finishing a study thesis (Studienarbeit). I presented my study thesis "Visualisation of Very Large Graphs" today at the mid-day seminar of the Theoretical Computer Science Group. The slides of the talk are available as PDFs below:

studythesis-talk-visualisation.pdf (1.6 MB) - also available with two slides per page (1.6 MB) or four slides per page (1.6 MB).

During the talk I showed a movie, in which a r-tree of the autobahnen of Germany is constructed incrementally. I actually produced two movies for this purpose: in the first the edges are added in a given sequential order and in the second the order is randomized. Both movies are encoded using transcode and the XviD codec.

Sequential Movie (3.6 MB)
Randomized Movie (5.1 MB)

The talk was received very well, and I may continue in this field with my diploma thesis.

The visualisation library is used by a route planning algorithm developed at the Theoretical Computer Science Group. By integrating my study thesis it was possible to create a Java web applet which animates the route planning algorithm. The Java applet is currently available at http://algo2.iti.uni-karlsruhe.de/schultes/hwy/demo/.

As part of my work for the SDI Lab work this summer, I held a short talk about how to design a name service in a multi-server operating system like L4.

The slides are available here:

Here the table of contents:

1. Goals
2. Name Catalogs
   1. Object Representation
   2. Catalogs
3. IDL Interfaces
   1. Resolve Interface
   2. Bind Interface
4. Extension / Ideas

Im Sommersemester 2005 habe ich am Praktikum "Real-Life Programming" am IPD Lehrstuhl der UniKa teilgenommen. Hier platt die Beschreibung von der Homepage zitiert:

In diesem Zusammenhang haben zwei Komilitonen und ich einen Vortrag über "Objekt-orientiertes Programmieren in C" (ohne ++) ausgearbeitet und gehalten. Weiteres Schwerpunktthema war die Darstellung von C++ in Maschine, also wie der C++ Übersetzer dann die Klassen abbildet.

Hier noch ein Auszug des Inhaltsverzeichnisses:

1. Objekt-Orientierte Konzepte
2. OO in C
   • Kapselung und Geheimnisprinzip
   • Vererbung und Polymorphie
   • Generiztiät
3. Darstellung von C++ in Maschine
   • vtable
   • Name-Mangling
   • Run-Time-Type Information (RTTI)

Diese Folien geben einen kompetenten Überblick über den Themenbereich.