Generating light with a specified spectral power distribution (April 2007)

Ivar Farup, Jan Henrik Wold, Thorstein Seim, and Torkjel Søndrol
A particular version of a spectral integrator has been designed. It consists of a xenon lamp whose light is dispersed into a color spectrum by dispersing prisms. Using a transmissive LCD panel controlled by a computer, certain fractions of the light in different parts of the spectrum are masked out. The remaining transmitted light is integrated and projected onto a translucent diffusing plate. A spectroradiometer that measures the generated light is also attached to the computer, thus making the spectral integrator a closed-loop system. An algorithm for generating the light of a specified spectral power distribution has been developed. The resulting measured spectra differ from the specified ones with relative rms errors in the range of 1%-20% depending on the shape of the spectral power distribution.
Optical Society of America, Applied Optics, Vol. 46, Issue 13, pp. 2411-2422 (OSA).

Gait Recognition Using Acceleration from MEMS (April 2006)

Davrondzhon Gafurov, Kirsi Helkala, Torkjel Sondrol
This paper presents an approach on recognising individuals based on 3D acceleration data from walking, which are collected using MEMS. Unlike most other gait recognition methods, which are based on video source, our approach uses walking acceleration in three directions: vertical, backward-forward and sideways. Using gait samples from 21 individuals and applying two methods, histogram similarity and cycle length, the equal error rates of 5% and 9% are achieved, respectively.
Proceedings of the The First International Conference on Availability, Reliability and Security, ARES 2006 (IEEE).

Biometric Gait Authentication Using Accelerometer Sensor (November 2006)

Davrondzhon Gafurov, Kirsi Helkala, and Torkjel Søndrol
This paper presents a biometric user authentication based on a person’s gait. Unlike most previous gait recognition approaches, which are based on machine vision techniques, in our approach gait patterns are extracted from a physical device attached to the lower leg. From the output of the device accelerations in three directions: vertical, forward-backward, and sideways motion of the lower leg are obtained. A combination of these accelerations is used for authentication. Applying two different methods, histogram similarity and cycle length, equal error rates (EER) of 5% and 9% were achieved, respectively.
Journal of Computers, JCP Oct/Nov 2006 (url).

Written Projects

These are some of the projects and publications I have written during the last couple of years. Most of them were created during the master course at Gjøvik University College.

Using the human gait for authentication - MSc Thesis (July 2005)

This MSc thesis presents a new method for verifying a person's identity using kinetic gait analysis. The gait data is collected using a device that can be attached to a person's leg, where it detects the leg's movement in horizontal, vertical and sideway direction as the person walks. These data are used in an attempt to authenticating the walking person. The creation of the gait detection device, the methods used for analysis, and the results from three experiments are presented (pdf).

Using the human gait for authentication - Preliminary Report (December 2004)

This is the preliminary report to my MSc project (pdf).

Contract signing using PGP (December 2004)

Achieving fair contract signing electronically is a difficult task. How can this be done such that one of the signers don't have an advantage over the other and such that an adversary can't sign the contract pretending to be one of the singers? This report suggests a way of achieving this using noting more than the standard mail protocol and PGP encryption (pdf).

Attacking fingerprint sensors (December 2004)

Biometric authentication is increasing in popularity, and the most popular method of biometric authentication today is the use of fingerprint. This report shows how we managed to fool several different optical and solid-state fingerprint sensors on the market (pdf).

Availability monitoring (October 2004)

This report proposes a method for monitoring the holistic availability of a service, i.e. the availability of the service from the user's point-of-view. This is necessary, since a server might be up and running and still unavailable to the user due to problems like spam or flaws in configuration or source code (pdf).

TLS extensions (May 2004)

On top of being an short introduction to the TLS protocol, this report describes several of the proposed TLS extensions to this protocol at the time of writing (pdf).

Hash functions (December 2003)

This report is an introduction to todays cryptographic hash functions, like MD5 and SHA1. It also describes our own hash function; SHAbeist, which we implemented to gain a better knowledge of how todays hash functions works. (In Norwegian only.) (pdf).