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Abstracts of Papers, Publications and more

Reports

Lectures

Groupworks

Software

Misc


Modelle des verteilten objektorientierten Programmierens

Vortrag am 21. September 1999, ZHR-URZ Seminar, ZHR TU Dresden

In den letzten zwei Jahren haben sich auf dem Gebiet des verteilten objektorientierten Programmierens drei verschiedene Objektmodellen etabliert:

Jedes dieser Modelle wird im Moment in relativ klar voneinander abgegrenzten Bereichen eingesetzt (COM/DCOM ausschliesslich bei Microsoft, CORBA beim Aufbau von verteilten Client-Server Systemen unter UNIX, JavaRMI bei der Entwicklung WWW basierter Anwendungen).

Obwohl die Entwickler dieser Modelle auf unterschiedliche Herangehensweisen bei der Erstellung verweisen, lassen sich dennoch eine Reihe Gemeinsamkeiten aufzeigen. In Vorbereitung eines Vergleichs sollen dazu CORBA, COM/DCOM und JavaRMI im Detail vorgestellt werden.

Ein Nachteil tritt bei der Einordnung in die "klassischen" Konzepte des objektorientierten Programmierens hervor: CORBA und COM/DCOM verfügen nicht über die Möglichkeit der Implementationsvererbung. Möglichkeiten zur Beseitigung dieses Mankos sollen anhand eines Systems, welches Konzepte von CORBA, COM/DCOM und JavaRMI in sich zu vereint diskutiert werden. Fuer dieses System sollen weiterhin Mechanismen zur Zustandsmodellierung, zum Scheduling und zur Migration von Instanzen eroertert werden.

gzipped XML - KPresenter 75 kByte (in German)
gzipped PDF 3.8 MByte (in German)


Programming on Convex Exemplar SPP1000

The Convex SPP/1000 Exemplar (Scalar Parallel Processing) is a shared memory parallel architecture supercomputer based on HP PA7100 processors. Each processor got 1 MByte Cache. It may work as stand alone (no host is necessary) running HP-UX. It is organized in a set of maximum 16 hyper-nodes, each containing up to 8 processors and up to 2 GByte shared memory with latency around 2.5 us over the full system. The hyper-nodes are connected via a CTI (Convex Toroidal Interconnect). According to the Convex Exemplar Programming Guide I tried out some small examples and collected the most important function calls to a small number of sheets.

compressed PostScript 30 kByte (in German)

I also gathered some basic principles of parallel computing which are independent from the used architecture.

compressed PostScript 30 kByte (in German)
compressed example source 8 kByte (! Convex SPP C)


Investigation on Noise Sensitivity of Atomic Force Microscopes

It is well known that Atomic Force Microscopes (AFM) are sensitive to sound and vibration. To quantify this sensitivity data were recorded from an AFM in a controlled sound environment. Using these data some qualitative and quantitative conclusions are done. Also some ideas how to prevent an AFM from such distortions are discussed.

compressed PostScript 258 kByte (in English)


Picture Processing on Scanning Tunneling Microscopy Data

This was my final project at the Technical University of Dresden.
In this publication the mathematical behavior of the most important image processing functions are discussed. A lot of investigation are done on the Discrete Fourier Transformation which is a very powerful tool for image processing. It was possible to give some error estimation for the DFT. Furthermore filter functions are discussed both in time and frequency domain. Some new filter functions are developed which proof the structure of an image to be the same before and after transformation.
Image processing is discussed also as part of system theory.
A polynomial fit algorithm is introduced using a QR factorization for solving. The problems of drift and creep are also discussed and a model is given (differing a little bit from that of J.F. Joergensen and not proved by experiments).
A great part deals with the visualization of the measured data. Therefore several interpolation algorithms are tested (Bi-linear and Tensor spline interpolation).
Finally the XRTMA program is introduced, which is an image processing tool based on the things discovered in the previous sections. It uses a X11/OSF-Motif Interface and runs on IBM/PC under Linux, IBM RS/6000 AIX and Convex C-series.
The program is capable to deal with IFW- (Institut fuer Festkoerperphysik und Werkstofforschung Dresden e.V.), NanoScope III-, plain text- and DFM- (Danisch Institute of Fundamental Metrology) formatted data. Different STM scanning modes (CCM, CHM) and AFM modes can be analyzed. The program also has the opportunity to handle potentiometric and spectroscopic data.
A great advantage is the scalability for special problems. The program comes with a very strict distinction between user interface and functionality. By using the included library it is possible to adapt the program to special problems. This is also possible by using an integrated script language.

diploma,
XRTMA Documentation, compressed PostScript 324 kByte (in German)
the XRTMA program, compressed archive 2.5 MByte, pre-compiled for Linux, AIX and Convex-OS, including sources

Note: The software is restricted by the rules for diploma works at the Technical University of Dresden and the Institute for Solid Physics and Surface Science IFW Dresden.
Copying and using the stuff is highly welcome but not selling it to a third party.


Illumination Models

In this paper the illumination models of Lampert and Phong are described, The ray tracing principle is discussed and a description of the implementation in the "spm" image processing tool of J. F. Joergensen (my supervisor at Danish Institute of Fundamental Metrology, Lyngby, Denmark) is given.

compressed PostScript 32 kByte (in English)


Simplified OSF/Motif Programming Interface

Simplified OSF/Motif - X Graphics Programming Interface

When starting X and OSF/Motif programming during my time in Denmark I where punished several times by using constants which I not knew nor could find somewhere (and believe me I had a look at nearly each page of the 1.5 meters documentation from IBM for the AIX system). This forced me to compile often used function with often used constants to a simple calling interface. Also to make it easy to port graphics code between X and non-X applications I wrote a small graphics module which uses X intrinsic calls in combination with the Motif toolkit.

xapp, compressed PostScript 73 kByte (in German)
xgraph, compressed PostScript 15 kByte (in German)
compressed archive 18 kByte


A report about basics of Object Oriented Programming and C++

This report was given at the Research Center Rossendorf as seminar at the Department for Communication and Data Processing (FVTK).
Here the basic principles of OOP are described, including a short history, the main concepts, the principle of inheritance, polymorphism and attribute/method scope rules.
In the second part a short introduction to C++ is given, including function overloading, class declaration, inheritance, virtual and abstract classes, generating objects, friends and operator overloading, some simple examples and some tasks for learning C++.

compressed PostScript 30 kByte (in German)


Introduction Seminar to Object Oriented Programming

In summer term 1997 we held an introduction seminar to object oriented programming. The seminar covers common aspects of the OO paradigm like abstract data types, polymorphism and inheritance. We introduce several OO languages, e.g. Oberon, Java, C++, Smalltalk, Turbo-Pascal, Ada. We also recommend some small problems to be solved in an OO style.

Seminar Script, PDF, 1.8 MByte
Introduction (Folies), PDF, 190 kByte
more information, downloads etc.


Introduction to Virtual Reality

In this talk a short introduction to what VR means is given. The talk covers aspects of influencing human senses, available systems and software as. In the second part a bases for creating distributed virtual environments is discussed and two different systems are introduced (DIS from U.S. Navy and my own). Before a demonstration of a working DVRE (distributed virtual reality environment) is taking place, the VRML language is introduced.

compressed PostScript 4.4 MByte (in German)


A Parallel Code For Kinetic 3D Lattice MC Simulations of Nucleation, Growth & Ostwald Ripening of Nanocrystals

Nils Schmeisser, Dr. Manfred Kunicke, Dr. Karl-Heinz Heinig

The report was accepted by the High Performance Computing Users Group Conference '98.

The continuing exponential increase in computer power together with the recent developments of very efficient numerical procedures allow nowadays to perform predictive atomic-scale computer simulations for material science. This holds especially for advanced microelectronic devices where functional units consists more and more often of 10^6 atoms or even less. In this situation the design of new materials and devices is more and more frequently supported by atomic-scale computer simulations.

A kinetic 3D Monte-Carlo code based on stochastic probabilistic two-centre cellular automaton using a double bookkeeping technique, one in the particle vector and the other in the lattice space was originally coded in PASCAL and tested on an INTEL PC, later in C and on HP workstations. This implementation should be speeded up considerably in order to undertake real scientific simulations. The only way to get the needed speedup is parallelisation.

We started with a look at the given sequential code and run it on our S-Class Server. While optimising we had to understand a lot of things, e.g. the double bookkeeping technique, so that we could do first steps of scalar optimisation during this process.

The most simple idea of a parallel approach is distributing the lattice across the processors. But because of the physical problem modelling the growth of clusters of implanted particles in the lattice such an approach will lead to load imbalances and destroy the effect of parallelisation.

With an another approach we tried to distribute the work done in the particle space instead of the lattice space. We developed a graph-theoretical approach based on skeletons to find out a work distribution across 2^n processors that assures a good load-balance. The disadvantage of this approach is the work needed to compute the distribution which is of order O(n^3) compared to the simulation which is of order O(n).

At this point it turned out the given model was not suitable for parallelising the algorithm. So we had feed-back with the physicist and together we developed a model of the physical process where the algorithm which solves the problem could be formulated in parallel. The new model allowed us to divide the solution into three main steps, where two of them can be done parallel and will therefor improve the speed of the algorithm.

We implemented this algorithm in a mixed language modularised program using FORTRAN for the computational part and C for the I/O part. The program runs on our S-Class server using maximum 8 processors.

In our presentation the methodology of creating an optimised parallel code for the Monte-Carlo simulation of Ostwald Ripening, the schema of the parallel code and first real physical simulation results will be shown.

compressed PostScript (340 kByte)
compressed PowerPoint (450 kByte)


XDAT V 1.1 Data Viewer

This small tool can display text based data like gnuplot. It is possible to choose 1D and 2D diagram style with color overloading. Single points can be checked out by clicking.

compressed archive 43 kByte


XWHO V 1.1 System Information

It looks like who it is who. The program displays all currently logged in users (by examining the files in /etc. You can get information on each user and on the whole system.

compressed archive 21 kByte


MViewer-1.0 Molecule Viewer

This small tools displays a molecule lattices in 3D. The lattice can be rotated around all axis. The Woboo Electronics LCD shutter glasses are supported for real 3D display. The driver is included to the archive.


snap-shot (Si lattice with marked unity-cell)

compressed archive 36 kByte


XPGP-1.0 PGP X11 front-end

This X11 front-end to pgp includes an integrated environment with an editor and controls to pgp as well as to the mail program.
It requires pgp and the UNIX command line mail to be installed.

compressed archive 23 kByte


Groupworks

Visualizing Surfaces given as f:RxR->R

K. Schuster, N. Schmeisser

In this paper we discuss several methods displaying a surface given in an explizit form of f:RxR->R:f(x,y)=z. We start with different types of projection (looking backward to the time we wrote it we have to state that now we would use homogenous coordinates instead of normal 3D vector space). Then we demonstrate different visual types (wireframe, iso-lines, solid surfaces). Finally we describe some methods for visibility checking (hidden-line, depth sort and an analytical approach). We also added information on how to make a real 3D image by the use of analglyph (red/blue) glasses. The paper comes together with an unit for Turbo-Pascal.

compressed PostScript 153 kByte (in German)
compressed archive


Up Department, Up Institute