Home – Home – Jornals – Advanced Search

A method of coupled interactions for real-time management of resource allocation is proposed. A distinctive feature of the method is the replacement of the enumeration of decision patterns, requiring high computational efforts, by bilateral negotiations aimed at detecting conflicts and reaching compromises between incoming requests and available means in constructing complex schedules. This feature provides significant advantages during solution of complex problems of real-time resource allocation, which can be important for corporate and government management systems.

A Shack-Hartmann type wavefront sensor designed on the basis of a low-aperture off-axis diffraction lens array is described. Tests experiments showed that the sensor is capable of measuring wavefront slopes at array subapertures of size 640Ч640 μm with an error not exceeding 4.80 arcseconds (0.15 pixel), which corresponds to the standard deviation (SD) (SD = 0.0170λ) at the reconstructed wavefront. Advantages of the array used in the sensor and the technology of its manufacture are discussed. The sensor tested in the experiments can be used to measure atmospheric turbulence parameters and as an element of adaptive optical imaging systems.

Results of analyzing chromatic aberrations of an eye model with different designs of intraocular lenses (IOLs), that is, artificial crystalline lenses (refractive, diffractive-refractive, diffractive, and harmonic, i.e., multiorder lenses) are represented. Investigations were carried out sequentially for elements of the model, namely, for a cornea, refractive and diffractive components, and IOL, and as a whole, for a cornea + IOL. It is shown that diffractive-refractive IOLs in which the diffractive components produce a positive additional focal power possess the best chromatic characteristics. Chromatic aberration of the eye model with such IOLs is 2 times less than that of a model with a refractive IOL, whereas with other IOL designs it is 2 times greater and even more.

Direct numerical modeling of propagation of optical pulses is performed to determine the "tails" of the probability density function of marks and spaces and the statistics of errors in an optical communication link on the basis of a standard single-mode fiber and a dispersion-compensation fiber with a reduced density of marks in the initial bit sequence. Simple analytical approximations for the tails of the probability density function are determined, which allows accurate estimation of the error probability in the link.

Micro-electro-mechanical systems (MEMS) are devices that display the most intense development in modern microelectronics. At the moment, however, the majority of electronic engineers and users of hi-tech devices do not possess sufficient general information about this new direction in microelectronics. The present paper describes the current status of this direction, numerous possible applications, and prospects of its further development, including the transition to the nanometer range and creation of nanoelectronic elements. Specific features of operation of some particular MEMS devices, their characteristics, and areas and scales of applications are considered.

This paper considers a new linear multichannel x-ray detector designed on the basis of a BLPP-369M4 silicon photodiode array (2612 photodiodes, array pitch 12.5 μm, height 4 mm, and dynamic range 104). The structure and characteristics of the multichannel detector are given, along with the Kα1,2, Kβ1, andKβ5 x-ray emission lines and a K-edge absorption spectrum of metallic copper recorded on a universal URS-2I spectrometer using this detector. The resolution and the signal/noise ratio of these spectra are superior to those of spectra recorded by an SRPP-21 gas ionization counter at the same recording time. The detector has a spatial resolution of 20 μm and an x-ray detection limit to equal 1 quantum at λ = 1.54 Å. It is suitable for studying the fine structure of absorption spectra at 1-10 Å.

Specific features of operation of one- and two-capacitor microelectromechanical converters (MEMC) of energy of mechanical microscopic vibrations into electric energy with a modulated electrode-gap magnitude and with allowance for the mutual influence of electrical and elastic forces are analyzed, and the characteristics of these two devices are compared. The main factors restricting the increase in MEMC power are demonstrated to be the effects of "collapsing" and the condition of conservation of positive rigidity of the system. Expressions for estimating the limiting MEMC parameters are derived. The possibility of electrical energy generation in the presence of "real" sources of wide-spectrum microscopic vibrations is considered.

An algorithm for optimal estimation (in the sense of the minimum average risk criterion) of the spatial position of non-Gaussian impulse noise in digital images is proposed based on the signal difference between the center of the slide aperture and its other elements. An expression for the boundary values of the admissible signal interval is obtained that provides the potentially achievable zero probability of noise estimation error. Results of numerical studies of the efficiency of the synthesized algorithm show its advantages over the well-known nonoptimal algorithm.

A frequency search algorithm for estimating polyharmonic signal model parameters is considered. The algorithm uses the symmetry property of functionals of residual partial sums. The proposed frequency search algorithm provides a decrease in the amount of calculation. The efficiency of solving the estimation problem is determined.

The problem of automatic recognition of half-tone images based on the minimum information discrimination principle is formulated and solved. A method of directed enumeration of the set of alternatives in the Kullback-Leibler information metric is proposed as opposed to the method of complete enumeration of competing hypotheses. A program and results of an experimental study of the method are presented. It is shown that the proposed algorithm is characterized by increased accuracy and reliability of automatic image recognition.