Classification of ultrasonic signals
In ultrasonic non-destructive testing it is very difficult to detect flaws in materials with coarse-grain structure. The ultrasonic signals measured on these materials contain echoes which are very similar to fault echoes. These echoes arise from grains which are contained in the material. For the detection of flaws various methods for suppressing echoes from grains have to be used. In this work we used the method for filtering ultrasonic signals based on discrete wavelet transform. For the classification of ultrasonic signals in A-scan we used a pattern recognition method called support vector machines. In this study we classify signals with fault echoes, echo from weld and back-wall echo. Ultrasonic signals were measured on materials used for constructing aeroplane engines. The experimental results indicate the performance of the proposed approach.
Ultrasonic sensor-based human detector using one-class classifiers
Human detection is vital to many applications, for example, human-robot interaction, unattended ground sensor systems, smart rooms, etc. In this paper we investigate the application of a one-class classifier to the problem of human detection using solely ultrasonic sensors. Our approach is based on fuzzy rules that are extracted from the signal features in time and frequency domains. The performance of the human detector system (classifier) is assessed in terms of accuracy, true positive, and false positive rates by conducting several experiments. The results show that the system attains high accuracy and high recall with a very low false alarm rate. We have also compared its performance with the widely used support vector machine (SVM) classifier and found that our system is relatively better than the one-class SVM.
Art and Value: Art’s Economic Exceptionalism in Classical, Neoclassical and Marxist Economics
Art and Value is the first comprehensive analysis of art's political economy to be found in classical, neoclassical and Marxist economics. It provides a critical-historical survey of the theories of art's economic exceptionalism, of art as a merit good, and of the theories of art's commodification, the culture industry and real subsumption. Through an exacting critique of mainstream and Marxist theories of art's economics, the book arrives at a new and highly original Marxist theory of art's economic exceptionalism.