Vol 25, No 2 (2016)

In the binary space of large dimension we analyze the nearest neighbor search problem where the required point is a distorted version of one of the patterns. Previously it was shown that the only algorithms able to solve the set problem are the exhaustive search and the neural network search tree. For the given problem the speed of operation of the last algorithm is dozens of times larger comparing with the exhaustive search. Moreover, in the case of large dimensions the neural network tree can be regarded as an accurate algorithm since the probability of its error is so small that cannot be measured. In the present publication, we propose a modification of the scalar neural network tree allowing the speeding of the algorithm’s operation up to hundred times without losses in its reliability.

Decision support in equipment condition monitoring systems with image processing is analyzed. Long-run accumulation of information about earlier made decisions is used to realize the adaptiveness of the proposed approach. It is shown that unlike conventional classification problems, the recognition of abnormalities uses training samples supplemented with reward estimates of earlier decisions and can be tackled using reinforcement learning algorithms. We consider the basic stages of contextual multi-armed bandit algorithms during which the probabilistic distributions of each state are evaluated to evaluate the current knowledge of the states, and the decision space is explored to increase the decision-making efficiency. We propose a new decision-making method, which uses the probabilistic neural network to classify abnormal situation and the softmax rule to explore the decision space. A modelling experiment in image processing was carried out to show that our approach allows a higher accuracy of abnormality detection than other known methods, especially for small-size initial training samples.

The paper analyzes the cross effect of nonuniform exposure nature on hologram field and nonlinearity of holographic material response which significantly adjusts the values of achievable aggregate diffraction efficiency and the optimum exposure. The cross effect is supposed to be registered with the help of a parameter named as a hologram formfactor by analogy with the description of complex body interaction. The technique for calculating formfactor is described. It is shown that the key differences when choosing the optimum exposure can be taken into account with the help of the correction coefficients defined with a hologram formfactor. The calculations for actual Gaussian holograms used in Holographic Memories as well as for model holograms being a good illustration to the dynamics of average diffraction efficiency versus exposure characteristic are made. The Gaussian holograms show good correlation with earlier empirical data.

Variants of liquid-crystal spatial light modulators control devices, that provide partial or fully parallel information input in multichannel optical signal processing systems are suggested. Applications of the proposed solutions enables to increase to a considerable extent the optical processors capacity that is actual for a number of practical problems.

Nonplanar ring optical resonators are considered, a measure of non-planarity of a resonator axial circuit is introduced. Influence of axial circuit non-planarity on polarization characteristics of ring optical resonators is investigated and non-planarity tolerances of a four-mirror ring resonator is estimated.