Prosjekt og diplomoppgaver tilbudt av Yurii Lyubarskii


(See also Projects related to the course on Fourier analysis)


Project 1

Reconstruction of bandlimited signals via their samples

The project relates to problems which appear both in signal analysis and complex analysis. The contemporary digital techniques of dealing with signals (sound records etc.) assume that a continuous signal is replaced by a sequence of its values (samples) at consequent moments of time, this sequence of samples is transmitted or stored, and later one reconstructs the original signal from this sequence of sampled values.

Since each "realistic" signal has a bounded frequency band the problem of reconstruction of such signals from their sampled values becomes one of the central ones. It was treated in many (now) classical works in signal analysis, but a lot of questions both theoretical and applied still remain open. These problems are related to noised signals, noised sequences of points and also signals with special behavior in time or/and frequency.

On the other hand each bandlimited signal can be prolongated from the real (time) axis to a holomorphic function in the whole complex plane and thus methods of complex analysis come into the play. They proved themselves to be very efficient.

Depending upon student's interests the project can deal with mainly either numerical or theoretical problems and can be designed for a group from one to three students.

The project can include collaboration with other research groups in particular with the group of Numerical Harmonic Analysis in Vienna Technical University, Austria (NuHAG)



Project 2

Wavelets and edge detection for medical images

Wavelets is a (relatively) new object in harmonic analysis which became widely used both in mathematics and (especially) in applied problems related to databases, signal and image processing. Expansions in wavelets (i.e. "small waves of various scales") happened to be efficient in some cases where the classical Fourier expansions do not work. The projects assumes studying the basis properties of wavelets and then using them for applied problem of edge detection on ultrasound images. This part of problem is joined with UNIMED, see typical pictures_1 and typical pictures_2 as well as some more details.
I also refer to previous projects for the reports on the related student projects already realized and also to newspaper article describing this project.

The project can be designed for a group from one to three students. The project can include collaboration with other research groups in particular with the group of Numerical Harmonic Analysis in Vienna Technical University, Austria (NuHAG)



Project 3

Summation methods for power series and plane waves.

The project relates to the problem of summation of the power series of a holomorphic function outside its circle of convergence.
This topic has a natural development in problems related to scattering of a plane wave on periodic surfaces and in studying of eigenfunction expansions for linear differential operators. The methods, which come from the function theory still work in this case!
Depending upon student's interests the project may contain both numerical and/or theoretical part.