Program and document directory

This page contains reports and software written and maintained by Ask Hjorth Larsen and possibly others. Feel free to use.

Links

A sample game of wires.

Wires

Wires is a tile-based puzzle where the player has to rotate a number of tiles, such that they form a connected graph. Wires offers a number of curious board topologies, including torus, klein bottle and moebius band. The link is an executable .jar file also containing the source. Wires requires Java Runtime Environment 1.5.0 or newer.

As of September 10, 2008, the difficulty on large boards has been increased substantially by making the generation of tetravalent tiles very unlikely.

 ___ ___ ___ _ _ _ 
|   |   |_  | | | |
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|__ |  _|___|_____|
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Localized Atomic Orbital Basis Sets in the Projector Augmented Wave Method. Master thesis, written at the Center for Atomic-scale Materials Design, department of physics, DTU. Describes the use of localized basis functions in the PAW method, plus generation of basis sets containing pseudo-atomic orbitals, empowered with extra radial functions and polarization functions for flexibility. Finally calculates the atomic force contributions on atoms, which can be used for molecular-dynamics simulations and structural relaxations.

This is all implemented and tested in GPAW, which is a Python implementation of the projector augmented wave method, a quantum mechanical method based on density functional theory. The software is capable of calculating things such as the energy of a molecule or a crystal. GPAW is part of the CAMd open source project CAMPOS, which means it is free software available under the GNU GPL.

Report (pdf)
Presentation (pdf)

Quick Latex to png converter

$T = - \frac12 \sum_n f_n \braket{\psit_n}{\nabla^2}{\psit_n}$ This is a small Python script which reads a Latex expression from a file or stdin and outputs a .png image. This is done by passing the input through latex and dvipng, which is less bothersome than having to type out the commands manually every time. The input is assumed to be a formula (such as the image alt text).

Topology Optimization

This page contains a number of animations showing steps of an optimality criterion optimization procedure applied to certain heat conduction problems. The optimizations were performed in a MATLAB/COMSOL environment, and the relevant scripts are available from the page. Authors: Kenneth Nielsen and Ask Hjorth Larsen.

Amplitude distribution resulting from a plane wave incident on a fully reflecting cylindrical object.

Wave Scattering using Numerical Methods

The report investigates a method for combining far field analytical and near field numerical solutions to wave scattering problems. Specifically considers shallow water waves such as tsunamis. Calculations are performed in a MATLAB/COMSOL environment. Authors: Martin Filskov Laursen, Kasper Reck, Ask Hjorth Larsen.

Basics of quantum computing

Assuming some basic knowledge of quantum mechanics, this report introduces concepts basic to quantum computing such as qubits, quantum mechanical gates and the significance of quantum entanglement. Following this the report describes briefly some notable applications of quantum computers, in particular prime factorization using Shor's algorithm. Authors: Martin Filskov Laursen, Kasper Reck, Ask Hjorth Larsen.

Cartographic projections

Part 1 introduces the notion of cartographic projections and derives some measures of the distortion, either by lacking conformality or equiareality (or both), which occurs with all cartographic projections according to Theorema Egregium of Gauss. Part 2 derives cylindrical projections such as the Mercator and Lambert projections which are conformal and equiareal, respectively.

A small part of the Mandelbrot set
which itself resembles the Mandelbrot set.

Fraktal: a fractal rendering program

Fraktal allows the user to quickly zoom around the complex plane, viewing fractals. Fraktal beta 0.2, the present version, supports the Mandelbrot set, Julia sets and a Feigenbaum tree generated from the logistic equation. Source (java).

Gettext translation page

This page contains utility scripts and information about gettext translation. Gettext is a software library used for internationalisation ("i18n") of programs.

Armoured forces advancing across the
Russian steppes.

JWars: a generic realtime strategy game in java

JWars, which is an acronym for JWars Warfare Simulation, is a semi-realistic realtime strategy game which includes API packages of general interest for games of the genre. The above link leads to the official JWars page. A primary objective of this game is to provide a control interface superior to those of contemporary games by embracing a military hierarchy where each formation possesses an AI capable of coordinating the actions of subordinates. The game offers a server/client multiplayer model. JWars is not under active development these days, but further work is planned some time in the future.

Executable .jar
Source .jar (java)
Report (pdf)

MIC Project: Cantilevers

This fagpakkeprojekt-report describes the fabrication and testing of semiconductor cantilevers which may be applied among other things as accelerometers. The report further documents the measurement of the spring constant of the cantilevers, along with measurements of damping ratio and resonance frequency of a cantilever-based commercial airbag sensor. Further testing of the fabricated cantilevers is documented in the report below. Authors: Martin Filskov Laursen, Kasper Reck, Ask Hjorth Larsen.

MIC Project: Cantilevers (cont.)

This small report completes the above project regarding semiconductor cantilevers. It describes the measurement of resonance frequency and damping ratio of the cantilevers and refines the methods used in the previous project. Authors: Martin Filskov Laursen, Kasper Reck, Ask Hjorth Larsen.

The oven in function. The graphite
heating element is visible, glowing red at a temperature of around 600
degrees celsius.

MIC Project: Chemical Vapour Deposition Oven for Fabrication of Carbon Nanotubes

This is the report for an experimental project on the development of an oven capable of generating conditions sufficient for growth of carbon nanotubes. Primary objectives are the construction of a heating element, pumps and controls for gas pressure adjustment, and a LabView program for measurement of temperature and pressure. Authors: Martin Filskov Laursen, Kasper Reck, Ask Hjorth Larsen.

Math project: Differentiable Manifolds

This document contains proofs of implicit- and inverse function theorems, and goes on to treat isometries in real vector spaces along with embeddings of differentiable manifolds in vector spaces. Finally there are some notes on germs of mappings. Authors: Mads Søndergaard, Laust Tophøj, Ask Hjorth Larsen.

This is the home page of Ask Hjorth Larsen also known as s021864. Updated: Sep 11, 2008.