In face recognition, one of the most important problems to tackle is a large amount of data and the redundancy of information contained in facial images. There are numerous approaches attempting to reduce this redundancy. One of them is information aggregation based on the results of classifiers built on selected facial areas being the most salient regions from the point of view of classification both by humans and computers. In this study, we report on a series of experiments and offer a comprehensive comparison between various methods of aggregation of outputs of these classifiers based on essential facial features such as eyebrows, eyes, nose, and mouth areas. For each of them, we carry the recognition process utilizing the well-known Fisherfaces transformation. During the comparisons of the vectors representing the features of images (faces) after the transformations, we consider 16 similarity$/$dissimilarity measures for which we select the best aggregation operator. The set of operators to compare was selected on a basis of the comprehensive literature review regarding aggregation functions.
Fuzzy cognitive maps (FCMs) are a class of discrete-time artificial neural networks that are used to model dynamic systems. A recently introduced supervised learning method, which is based on real-coded genetic algorithm (RCGA), allows learning high-quality FCMs from historical data. The current bottleneck of this learning method is its scalability, which originates from large continuous search space (of quadratic size with respect to the size of the FCM) and computational complexity of genetic optimization. To this end, the goal of this paper is to explore parallel nature of genetic algorithms to alleviate the scalability problem. We use the global single-population master-slave parallelization method to speed up the FCMs learning method. We investigate the influence of different hardware architectures on the computational time of the learning method by executing a wide range of synthetic and real-life benchmarking tests. We analyze the quality of the proposed parallel learning method in application to both dense and sparse large FCMs, i.e. maps that consist of several dozens of concepts. The parallelization is shown to provide substantial speed-ups, allowing doubling the size of the FCM that can be learned by parallelization with 8 processors.
