To deal with the real-world problems characterized by complexities and uncertainties, the design of the fuzzy filters is an important issue since the real-world applications require the filtering of uncertainties from the experimental data. Thus, we studied the adaptive fuzzy filtering problem based on different estimation criteria. The studied mathematical criteria include followings:
# Robust Regularized Least-Squares Estimation
# H-infinity Optimal Estimation
# Least-Squares Estimation
# Generalized Least-mean-squares like p-norm Algorithms
# Risk-sensitive Estimation
A mathematical theory was developed for the stability, robustness, and steady-state analyses of fuzzy filtering algorithms. This facilitates a computational paradigm to implement an intelligent behavior in the sense of handling uncertainties related to the modeling of the complex and uncertain processes.
This work, being supported by Center for Life Science Automation and Institute for Preventive Medicine of Rostock University, presented a novel method of heart rate signal analysis for stress assessment using fuzzy clustering and robust identification techniques. The emphasis of this study was to handle the uncertainties, arising due to a difference in the physiological behavior of individuals (because of different body conditions, age, gender, and so on), using a fuzzy model.
The aim of this project supported by European Space Agency was to develop a fuzzy expert system for estimating the physical fitness of a patient on a scale from 0 to 1. The complex and uncertain relationships between some of the physiological parameters measurements and opinion of a medical expert about the fitness level of the patient are modeled using a fuzzy inference system.
The Center for Life Science Automation Rostock supported a project for carrying out a research on computational intelligence based drug design. The aim of the work was to develop a fuzzy based computer model for a prediction of the drug activity of a chemical compound from its structure. The computational intelligence techniques were used to remove some of the bottlenecks in structure-activity modelling poroblems.
A joint work with the Institute of Chemistry of Rostock University involved the modeling of the environmental behavior of chemicals. A fuzzy based expert system was developed for predicting the toxicity and bioconcentration factor of chemicals.
This study suggests the use of fuzzy filtering algorithms to deal with the uncertainties associated to the interpretation of analysis of physiological signals. The signal characteristics, for a given situation or physiological state, vary for an individual over time and also vary among the individuals with the same state. These random variations are due to the several time-varying factors related to the physiological behavior of individuals which can't be taken into account in the interpretation of signal characteristics for solving a medical decision making problem. The approach is to reduce the effect of random variations on the analysis of signal characteristics via filtering out randomness or uncertainty from the signal using a nonlinear fuzzy filter.