Optoelectronics, Instrumentation and Data Processing (v.46, #2)

This paper considers the state and prospects for studies of the central problem of the theory and practice of automatic control—the problem of controller synthesis for systems with nonlinear plants. A crucial factor in the performance of controllers for nonlinear plants is the use of deep feedback for derivatives of the output variable, which provides localization of disturbances in fast subprocesses (against the background of the main processes) and allows the generation of the required dynamic properties
Keywords: output-variable derivatives; localization of disturbances; method of separation of motions; small parameters; large coefficients

The degeneration property of dynamic multivariable control systems is considered. In this work, by degeneration for a multivariable systems is meant primarily a decrease and even a loss of its operating capacity. A technique of quantitative assessment of the tendency of multivariable control systems to degeneration was developed using a singular decomposition of criteria matrices formed on the basis of the matrix formalism of Faddeev-Leverrier algorithm, Gramian representation, matrix coefficient of the expansion of the system output vector in the derivatives of the control input vector, and with the use of the matrix formalism of Sylvester’s and Lyapunov’s equations
Keywords: multivariable control; multivariable system; quantitative assessment of degeneration; singular numbers; degeneration functional; criteria matrix

Experimenting with large-scale, multi-agent software systems yields insight into factors that determine the capability of complex systems to operate at the edge of chaos without disintegrating. The research results are generalised and applied to the diagnosis of the failure of the global financial system.
Keywords: complexity; self-organization; emergence; evolution; adaptation; agent-based software; global financial systems

Fuzzy approximator of atmospheric temperature fields by M. Yu. Kataev; A. V. Lavygina; I. A. Khodashinskii; D. A. Epshtein (134-141).
Algorithms of constructing a fuzzy approximator of atmospheric temperature fields are considered. The consequent parameters of the fuzzy rule approximator are determined using the leastsquares method, and the antecedent parameters are determined by the genetic algorithm. Results of a numerical experiment are presented. Optimal approximator parameters are given.
Keywords: fuzzy systems; approximation; genetic algorithm; least-squares method

Maximum likelihood algorithms for estimating the area of stochastic images against a stochastic background in the presence of spatial noise are synthesized. A comparison is made of area estimation algorithms based on the additive and applicative models of interaction between the image and background. Asymptotic expressions for the characteristics of the area estimators are obtained. The effect of the difference between the statistical characteristics of the background and image on the accuracy of image area estimation is studied.
Keywords: Gaussian image; background; spatial noise; unknown area; applicative model; efficiency of area estimator

Cluster analysis of earth remote sensing data by V. V. Asmus; A. A. Buchnev; V. P. Pyatkin (149-155).
A system of cluster analysis (unsupervised classification) for Earth remote sensing data is considered. The system is represented by three methods: the K-means method, the mode analysis of multidimensional histograms, and a hybrid method which combines the mode analysis of multidimensional histograms with their subsequent hierarchical grouping.
Keywords: remote sensing; pattern recognition; cluster analysis

Simultaneous estimation of liquid level and density based on the maximum likelihood method by E. N. Abrosimov; A. S. Semenov; A. L. Shestakov (156-162).
This paper considers the operation algorithm of a hydrostatic level sensor in a liquid of unknown density which is based on the determination of the moment when the level crosses the pressure sensor and provides increased accuracy of density and level measurements compared to available methods. The algorithm was synthesized on the basis of the maximum likelihood method. The algorithm was analyzed and experimental data are given.
Keywords: algorithm; level; density; error; estimation

The geometric and information parameters of the page-oriented holographic memory are optimized with allowance for the cross-talk influence on the recording density and on the bit error rate.
Keywords: holographic memory; cross-talk; recording density; bit error rate

Microstructuring of optical surfaces: Technology and device for direct laser writing of diffractive structures by A. G. Poleshchuk; A. A. Kutanov; V. P. Bessmeltsev; V. P. Korolkov; R. V. Shimanskii; A. I. Malyshev; A. E. Matochkin; N. V. Goloshevskii; K. V. Makarov; V. P. Makarov; I. A. Snimshchikov; N. Sydyk uulu (171-180).
Results of development and testing of a scanning system of interference lithography are presented. The system is designed to form diffractive microstructures consisting of microgratings with a specified orientation, a size of 5–10 µm, and a period ranging from 0.6 to 1.5 µm. The total writing field of the system is 300 × 300 mm. The system is used to study direct laser writing of microgratings on chromium and amorphous silicon films applied by the method of magnetron sputtering onto the glass substrate surfaces. The device and technology of direct writing of microgratings can be further used to form antireflective subwave coatings of optical elements and graphical microstructured identification marks for product protection and also to manufacture diffractive attenuators of laser radiation.
Keywords: scanning interference lithography; direct laser writing; diffractive microstructures; chromium films; silicon films

Splitting of orthogonally polarized radiation components at the exit of birefringent crystal prisms (BCPs) having a special structure and fabricated from uniaxial Iceland spar crystals is studied by the vector analysis method. For these prisms, the angle of splitting between the ordinary (o) and extraordinary (e) beams at the BCP exit depends linearly on the angle of incidence of a collimated laser beam onto the BCP entrance face. This dependence has the maximum slope only for two fixed orientations of the optical axis vectors a 1 and a 2 in both crystal wedges (BCP components). As a result of interference of polarized o- and e-waves, a straight-line interference pattern with a controlled and smoothly changed spatial frequency in the range from 0 to 125 periods/mm can be formed directly at the BCP exit. The BCP ability to form a sinusoidal interference pattern with the modulation depth not lower than 30% and with a varied spatial frequency at the aperture up to 30 mm makes it possible to use the BCP as a basis for creating a compact static Fourier spectrometer with the ultimate theoretical resolution λλ up to ∼2000.
Keywords: crystal optics; birefringent prism; polarization; interference pattern; spectral instruments

Interference microscope-profilometer by E. V. Sysoev; I. A. Vykhristyuk; R. V. Kulikov; A. K. Potashnikov; V. A. Razum; L. M. Stepnov (198-205).
The structure and functional capabilities of a digital optical microscope-profilometer capable of operating in two modes, those of micro- and nanomeasurements, are presented. The instrument operation principle is based on measuring the phase function of the wave front of light scattered by the measured surface. Software for the microscope-profilometer and its performance characteristics are considered.
Keywords: optical profilometer; scanning interferometer of partially coherent light; nanorelief; 3D-reconstruction; microrelief