The problem of efficiency estimation for an object-detecting facility is discussed on the base of detection theory. Consideration is given to detection probability as the major characteristic of the detecting instrument in question, and contact probability accounting for the effect of noise on location procedure. Equations are derived for the detection probability and for a quantitative characteristic of the detection productivity.

The new method is proposed for estimation of spectral density of signal energy and detailed components obtained with the use of discrete wavelet-decomposition of the signal. Efficiency of the method is checked upon investigations of surface profiles of metallic samples and temporal series corresponding to kinetic tremor of human hand arising in keeping isometric force of the human hand.

A portable complex of instruments operated under a unified program shell for express-diagnostics of state of human health is developed and affords a quasi-continuous monitoring of cardiovascular, digesting, endocrine, urinogenital, respiratory, and nervous systems. Schematics of hardware and flowcharts of software are presented. Classification of states of health and algorithm of diagnostic decision are described.

The problem of adaptive optimization of linear systems under parametric and functional uncertainty, and lack of information on the sign of high-frequency gain is considered. A solution to the problem is obtained on the base of modified adaptation algorithm of a high order with the use of a function allowing for compensation of the sign uncertainty. Results of numerical modeling are presented.

The problem of optimal control over nuclear reactor on the base of incomplete data is considered. The proposed solution to the problem exploits the separation principle with linearized Kalman filter and the minimax control algorithm. Numerical modeling is used to derive initial parameters of the boundary-value problem affording convergence of iterative procedure when random perturbations occur.

Application of data stream analysis in broadcast storms detecting methods and in dynamic construction of a network topology is considered. A technique for broadcast storm detection in a network, location of the storm source and invaded area is proposed. Comparison is presented of criteria used for detection of identical sequences of network traffic patterns. A software developed for processing of statistical data on network performance is described.

Mathematical modeling of detection systems for network intrusion is considered. A method is proposed for network anomalies detection based on multicriteria prediction of security indices. Problem of computation of weighting coefficients accounting for time-dependent significance of prediction model is formulated and solved. The proposed approach is characterized by low enough computational complexity and does not depend on the type of criterion used for optimal prediction choice.

Nonlinear distortion of signal introduced by electron amplifier is investigated theoretically. Nonlinear distortion factor is calculated for a harmonic input signal. For a specified volt-ampere characteristic, the effect of operation point position on the nonlinear distortion level is analyzed.

Class of problems related to automation of health services provided by physicians in extreme conditions of polar zones is considered. Requirements on medical electronic instruments and other equipment used in Arctic and Antarctic expeditions are formulated. Approaches and solutions are described that have been applied in development of hardware and software components of automated working place of a polar doctor. The results are introduced into medical information system for polar expeditions.

The problem of affording potential noise stability of opto-electronic equipment at low contrast between registered object and background is discussed. Formulas are derived for potential sensitivity of opto-electronic devices for the case when the sensitivity is limited by photon noise of background current.

Analysis is presented of basic components of random error in measurement of radial expansion of an irradiated surface; the components in question include error caused by noise-induced shift of reading point, error determined by the signal level at a priori uncertain shape of irradiated surface and its reflectance, anomalous error occasioned by acceptance of noise excess for signal.

Graph models are proposed for the space of allowable solutions to the problem of arrangement of electronic elements with the account for both communication and thermal criteria. Examples of suggested models are presented for various conditions of heat removal determined by module design of electronic devices.

Results of numerical modeling of operation of low-temperature thermoelements in maximal temperature difference mode are presented. The boundary value problem is solved for stationary thermal conductivity of thermoelement branches with temperature-dependent kinetic factors. Comparison is performed for efficiency of a р-branch thermoelement from bismuth telluride with that of a passive branch thermoelement from a hightemperature superconductor. Influence of contact resistance on thermocouple efficiency is taken into account.

Description is presented of laboratory of low-temperature physics opened up at St. Petersburg State University of Low-Temperature and Food Technologies. The laboratory incorporates 14 test benches including thermal cells, controller, and various thermal data units. The laboratory is intended for scientific research but may also be used in education.

Projection laser irradiation method is applied for formation of regular array of silicon nanoclusters within SiO2 layer on silicon substrate. Pulsed fiber YLP laser with the wavelength of 1.06 μm is used as radiation source. Metal micro grid was introduced for laser beam splitting, and the resulting elementary beams are focused at oxidized silicon substrate with oxide thickness of 100 nm by objective lens. Density of silicon clusters in the array is shown to depend on the micro grid cells size. Threshold laser power is determined, and excess of the threshold is found to result in formation of a regular array of silicon nanocluster within the oxidized layer of silicon substrate. The clusters size increases and deformed areas arise around the clusters with further increase in laser power.

The problem of automatic quality assurance for welded seams is addressed to on the base of computer technologies with the use of measuring technical vision and elements of a robotics. A complex virtual device is described which is intended for control over measuring / imaging instrument and for processing of obtained images.

Metrological approach is elaborated to the problem of automated testing of professional training level in the high school.