ISSN 0021-3454 (print version)
ISSN 2500-0381 (online version)
Summaries of the issue


The problem of improvement of information protection systems is analyzed on the base of an estimate for the efficiency of information threats combating process in large information systems. The process of combating of threats to an element of information system of an enterprise is represented as an aggregated time-operation model. A mathematical technique based on random variable distribution law is employed. An assessment of time costs correlation with the efficiency of information protection for separate information structures is presented. Efficiency of the process of previously unknown treats combating by an information protection system built on the adaptation principle is estimated. The adapting schema is shown to allow for reconstruction of the structure of information protection system depending on the impact nature.
The basic problems of effective measures selection in forest fires prevention are discussed. Mathematical models are developed for quantitative estimating the fire hazard level and possible damage in the case when initial information is incomplete. The presented models treat wildfire as a random event; Walley criterion or the maximality condition is applied for decision support in forest fire prevention measures determining. The generalized Dirichlet model and Bayesian approach are used for assessment of forest fire hazard level. The proposed models are easy to implement in software and employed in complex systems of decision support.
The process of live migration without shared storage with post-copy approach is studied. An algorithm of live migration of virtual machines is considered from the view point of migration time investigation and unavailability of services. An analytical model is proposed for predicting the migration time and time of unavailability of services, for example, at management implementation of preventive and emergency works on the physical nodes in data centers.
Completing of situation-oriented database model with specialized means for interaction with database management system MySQL is considered. An improved model of situation-oriented database (SODB) is proposed; the model extends the capabilities of the use of XML-data stored in a relational database MySQL. As a result, the proposed model is provided with tools for the database connection and management of its facilities. The interaction consists in creation of databases, tables, entering sample data and updating data; the functions are realized on the platform of SODB dynamic model interpreter developed with the use of PHP technologies. The model has an XML-based representation and equivalent representation in the form of diagrams.


A method of spacecraft center of mass motion control using information on line of sight of the passive orbital object to be approached is considered. The structure and value of the coefficient of quasi-optimal fast control law is determined. The coefficient value is adjusted with the account for the spacecraft angular dynamics and acting disturbances, and the distance to the object appropriate for transition from long-range to short-range guidance is defined.
The possibility to improve efficiency of data exchange over redundant channel is analyzed for the case when the channel is used for request for transmission of data packets sensitive to delay of faultless delivery to the addressee. The effectiveness of redundant transmission of packet copies over several channels is considered to allow for compromise between decrease of average time of request processing and requirements for faultless transfer for a given time for systems with excluded feasibility of repeated packet sending due to delivery time limitation. The existence of optimal multiplicity of backup copies and an area of effectiveness of redundant data transfer over an aggregate channel are demonstrated on the base of additive and multiplicative criteria.
ERROR ANALYSIS FOR THE MEMBRANE SENSING ELEMENTS OF CONTROL SYSTEMS Kozlov Aleksei S., Labkovskaya Rimma Ya., Pirozhnikova Olga I., Tkalich Vera L.
Dynamic and static errors of the membrane sensitive elements of control systems under complex mechanical and thermal influences are analyzed. The strain called the membrane element stroke is taken for the unified parameter accounting for interconnection between aerodynamic, hydraulic, mechanical, and thermodynamic complex effects. Mathematical models allowing calculation of the static and dynamic errors of the membrane sensing element of control systems exposed to various mechanical and thermal influences are constructed. The developed approach has been used in designing of several magnetic contacts with increased reliability and improved performance applied in burglar and fire alarm systems.


Three options of photometric wedge formation and employment in digital photometric shadow method are described. The methods allow for building the wave front deformation map and evaluation of image quality characteristics for the optical system under investigation from a pair of digital patterns processed with the use of specially designed software.
OPTICAL-ELECTRONIC INSTRUMENT FOR CONTROL OVER GEOMETRICAL PARAMETERS OF DIFFUSE REFLECTING OBJECTS Prokopenko Victor T., Majorov Evgeniy E., Mashek Alexander Ch., Udakhina Svetlana V., Tsygankova Galina A., Khaidarov Andrey G., Chernyak Tatiana A.
An optical-electronic instrument operating in scanning and trigger modes is developed on the base of Michelson interferometer. Analysis of a complex-shape surface is carried out; random modulations of interference signal and measurement errors caused by variation of optical path length of object beam at tangential movement of the object are studied. A method is proposed for minimization of the effect of speckle-modulation of interference signal by increasing the number of independent measurements during one pass of optical measuring head and subsequent averaging. The method realization employs an additional modulation of optical path length difference. Experimental results obtained with the instrument make it possible to determine the measurement discreteness and the limit of allowable speed of diffusereflecting object movement during the dynamic measurements.


Various ways of replicating the projection screen elements with raster reflective coating are considered. Technologies using shock-matrix method, laser structuring, 3D-printing, and method of galvanic copying are analyzed. Results of investigation of samples manufactured with the above technologies are presented; optical characteristics of the samples are examined.
MICROLENS ARRAY FABRICATION ON FUSED SILICA BY LIBBH TECHNOLOGY WITH CO2 LASER SMOOTHING Roman A. Zakoldaev, Galina K. Kostyuk, Сергеев М. М., Yakovlev Yevgeniy Borisivich, Koval Vladislav V., Rumkevich Vladimir S.
A new technology for microlens array fabrication is presented. The technology is based on creation of the initial microstructures on fused silica by laser indirect method, and the following reflow process of these structures made by CO2 laser action. Microlens arrays with diameter of microlens equal to 150 μm are fabricated. The focal length of microlens varies from 5 up to 5 mm. Profiles of formed microlens correspond to circle equation.


В высших учебных заведениях Российской Федерации за многие годы накоплен огромный опыт по раскрытию творческого потенциала учащихся при решении профессионально-ориентированных задач на студенческих олимпиадах. Всероссийские олимпиады позволяют  оценить готовность студентов к деятельности в стрессовых ситуациях, быстроту нахождения оптимальных решений, уровень знаний и навыков, способность видеть нетиповые решения. Всероссийская студенческая олимпиада (ВСО) по прикладной механике, которая с 1999 г. проводится в Санкт-Петербургском национальном исследовательском университете информационных технологий, механики и оптики, является отличным примером такого рода мероприятий. Участники должны не только продемонстрировать умение решать задачи по таким дисциплинам, как „Теоретическая механика“, „Сопротивление материалов“, „Детали машин и основы конструирования“, „Теория механизмов и машин“, „Основы взаимозаменяемости“, но и находить решения комплексных задач.