In 2000, the Signal Processing and Speech Communication Laboratory (SPSC Lab) of Graz University of Technology (TU Graz) was founded as a research and education center in nonlinear signal processing and computational intelligence, algorithm engineering, as well as circuits & systems modeling and design. It covers applications in wireless communications, speech/audio communication, and telecommunications.

The Research of SPSC Lab addresses fundamental and applied research problems in five scientific areas:


Result of the Month April 2015

Previous results of the month

The influence of different message update schemes on belief propagation (BP) highlights the need of designing an appropriate message scheduling. Yet, Residual belief propagation (RBP) is the only established method utilizing this observation and consequently increasing the convergence rate.
We observed that RBP fails to converge if local oscillations occur and the same messages are repeatedly updated. We propose two novel methods to prevent and correct such oscillations. First we show how noise injection belief propagation (NIBP) detects oscillating messages and adds random noise to improves the convergence rate. The second method, weight decay belief propagation (WDP), applies a damping on the residual to gradually reduce the relevance of these messages and consequently forces convergence.
Additionally, in contrast to previous work, we consider the correctness of the obtained marginals and present the remarkable performance increase on a variety of synthetic problems.