Subject of Research. The paper presents a relatively simple method to develop interactive computer models of physical systems without computer programming skills or automatic generation of the numerical computer code for the complex physical systems. Developed computer models are available over the Internet for educational purposes and can be edited by users in an unlimited number of possibilities. An applicability of  computer simulations for the massive open individualized teaching and an organization of undergraduate research are also discussed. Method. The presented approach employs an original physical object-oriented modeling method, which is an extension of object-oriented programming ideas to tasks of developing simulations of the complex physical systems. In this framework, a computer model of the physical system is constructed as a set of interconnected computer objects simulating the system components: particles and fields. Interactions between the system components are described by self-adapting algorithms that are specified during the model initiation stage and are set according to either the classical or relativistic approach. The utilized technique requires neither a priori knowledge regarding an evolution of the physical system nor a formulation of differential equations describing the physical system. Main Results. Testing of the numerical implementation and an accuracy of the algorithms was performed with the use of benchmarks with the known analytical solutions. The developed method - a physical reality constructor - has provided an opportunity to assemble a series of computer models to demonstrate physical phenomena studied in the high school and university mechanic courses. More than 150 original interactive models were included into the collections of multi-level multimedia resources to support teaching of the mechanics. The physical reality constructor was successfully tested to serve as a test bed for the independent research by students on physical properties of complex mechanical systems, the analysis of which is beyond the scope of the standard physics and mathematics curriculum. The heuristic capabilities of models created by the physical reality constructor were also demonstrated. The capability to investigate dynamics of the complex systems, an a priori analysis of which is not evident or with a difficult or impossible-to-calculate evolution, was also demonstrated. Practical Relevance. The developed computer program for automated development of interactive  educational simulations provides a solution to standing problems in accompanying massive open individualized learning multi-level courses in physics as well as an opportunity to develop creative forms of training in physics with elements of research.

The features of human skin response to the impact of femtosecond laser radiation were researched. The Monte–Carlo method was used for estimation of the radiation penetration depth into the skin cover. We used prevalent wavelength equal to 800 nm (for Ti: sapphire laser femtosecond systems). A mathematical model of heat transfer process was introduced based on the analytical solution of the system of equations describing the dynamics of the electron and phonon subsystems. An experiment was carried out to determine the threshold energy of biological tissue injury (chicken skin was used as a test object). The value of electronic subsystem relaxation time was determined from the experiment and is in keeping with literature data. The results of this work can be used to assess the maximum permissible exposure of laser radiation of different lengths that cause the damage of biological tissues, as well as for the formation of safe operation standards for femtosecond laser systems

The paper deals with results of the study on the main technological aspects relating to a full production cycle of silica multimode graded-index fibers with the refractive index profile having central defect in the form of a large dip. Preform synthesis conditions for implementation of the mentioned defect via MCVD method have been analyzed and optimized. We have carried out research of the effect of geometrical irregularities, induced by drawing optical fibers under the manual control of the outer diameter stability, on attenuation coefficient of the graded-index 50/125 μm optical fibers with a large dip in the center of the refractive index profile. It is shown that variations of the outer diameter within the limits ± 3.5 μm lead to an increase of attenuation by 2–5 dB/km at the wavelength λ = 1310 μm as compared to the optical fibers fabricated under the automatic maintenance of the outer diameter stability. It has been determined that in the latter case fibers with the parabolic refractive index profile, corresponding to numerical aperture of 0.20, and the dip depth equal to 0.0115 demonstrate the attenuation about 5 dB/km in the second and third optical fiber transmission windows. Applying the Weibull distribution, a statistical evaluation of mechanical properties of the optical fibers drawn at various temperatures has been carried out. Based upon measurements, tensile strength of the fibers was estimated to be 5.07–5.49 GPa, that is comparable with the strength properties of silica telecom fibers. The manufactured multimode fibers are attractive candidates for developing sensing elements of registering external influences in systems of fiber-optic sensor networks based on few-mode effects.

The paper deals with a method of ultraviolet objective design for optical lithography. The approach to such complex lens design is to split the complex objective into the two simpler ones. The front objective has the object at the finite distance and the image placed at the infinity. The second (receiver) part of lithographic lens acts as an ordinary photographic objective. The separate parts of complex objective have been calculated independently and combined into a single complex lens with the subsequent cross-cutting optimization of parameters. The two independent parts of lithographic lens are combined in an aperture stop plane. The both lenses are designed according to the scheme  with an external entrance pupil. In order to generate starting points of optical systems, we have used the elements of artificial intelligence in lens design software, SYNOPSYS, OSD. The proposed method describes the steps of obtaining feasible starting points and solves the typical optimization challenges within the systems with high aperture. The calculations of characteristics are explained on an example of bi-telecentric lithographic objective. The objective is optimized as a diffraction-limited system for the spectral range from 362 to 368 mm where the principal color is 365 nm. The Strehl ratio at the principal color of 365 nm at the edge of the field is equal to 0.989. The objective has a total track of 630 mm, consists of the 18 lenses with 4 aspherical surfaces. The total magnification is 0.2, with the distortion less than 1 %. The image size is 22×22 mm2. We have used S-FPL53, S-FPL51Y, BAL15Y glass material for the positive lenses and PBM2Y, PBL25Y for the negative lenses. The simulated internal transmission after the adding of antireflection coating is equal to 43 %.

Subject of Research. The paper deals with methods of resolution enhancement, as well as stability and repeatability of photolithographic process with the use of complex shape light source. Possibilities of source shapeoptimization to be used with specific patterns or pattern groups are shown. Methods. We applied "Simulated annealing" stochastic algorithm for source optimization for periodic patterns with a various pitch. The periodic patterns contrast with a various pitch (including "forbidden" pitch) was used as a merit function, as well as the area of elliptical process window for photolithographic setup.  Research was carried out with the aid of Sentaurus Lithography program (Synopsys Inc). Main Results. Optimization of periodic patterns with 150-300 nm pitch, 193 nmwavelength and optical system numerical aperture equal to 0.93 is shown as an example. The case of optimization algorithmwith focus-expose matrix is considered. It is shown, that proposedsource optimization with the use of the algorithm allows increasing image contrast for various pitches, as well as the area of process windowforphotolithographic setup. The convergence study shows that 100 iterations are enough for the source optimization for 600-800 nm mask pitch and further increasing of iteration number has no impact to the contrast. Practical Relevance.The studied algorithm can be used as a replacement for more complex algorithms of source optimization for reducing the minimum element size and the process stability enhancement. The algorithm has high convergence.

Subject of Research. The paper presents the laboratory colorimeter for determination of color parameters of objects with a diffuse reflection. We discuss design features, performance and metrological characteristics, calibration algorithm of the device in XYZ and RGB color systems. Findings for color parameters of aesthetic dentistry materials are given.Methods. The light-emitting diode and the RGB-photodiode were first used as an emitter and a photodetector in the colorimeter design. The integrating sphere with an internal baffle was also applied. Illumination distribution numerical modeling in the sphere with the internal baffle located near its center was carried out. Test samples of nanocomposites diffuse reflectors for aesthetic dentistry were examined.Main Results. The precision of measurements of color parameters determined with the use of photometer-colorimeter and the ones determined from reflection spectra within the reflection index range equal to 4-90 % was no worse than ∆X, Y, Z = 0.2. Thus, the presented colorimeter responses to the practical exploitation of the colorimetry.Practical Relevance. The presented device is being tested in Pavlov First Saint Petersburg State Medical University.

The paper deals with the problems of excimer laser pulse energy measurements. The goal of the current work is to research and develop the construction and characteristics of laser energy meter based on the photoelectric films of indium-tin oxide. Photoelectric voltage linearly depends on the laser pulse energy. We propose the construction and electric scheme of the energy meter. Comparison of the measurement results of photoelectric energy meter and pyroelectric energy meter is carried out. It is shown that the measurement error of photoelectric energy meter does not exceed the one for pyroelectric energy meter. Also it is found that photoelectric energy meter has several advantages: mechanical shock has no influence on the energy meter results, energy meter requires no zero level calibration, sensor temperature dependence is less than for pyroelectric meter. We measure the work energy diapason for the meter sensor element. It is shown that the surface degradation occurs under the irradiation with energy density equal to 78 mJ/cm2.

Subject of Research. Application of refractometric analysis in multiple myeloma diagnostics is proposed for the first time. Multiple myeloma (MM) is a disease of the hematopoietic system characterized by active monoclonal protein synthesis being detected in blood serum and/or in urine. Method. The essence of method consists in measuring of the sample refractive index. The value of refractive index depends on physicochemical characteristics of the optical mediums. Differences between refractive index of patients with multiple myeloma and donor blood serum connected with typical protein and electrolyte imbalance were researched. Main Results. Refractometric analysis data have shown strong correlations between protein concentrations in serum of patients with multiple myeloma and serumrefractive index. Refractive index of serum of patients with multiple myeloma firstly depends on protein concentration rather than on an electrolyte imbalance. The main tendency for patients with multiple myeloma is a higher level of both protein and electrolytes concentration in serum, in contrast to healthy people. Practical Relevance. According to the obtained data, refractometric analysis is considered as one of the suitable methodsfor express-diagnostics of diseases, in particular, multiple myeloma.

Subjectof Study.We present research results of the free motion of discrete linear systems in case of the control signal transmissionto continuous plantwith a delay not exceeding the discreteness interval duration. It was foundthat if the output control signal delay does not exceed the discreteness interval durationthen the dimension of the discrete representation of the continuous plant is increased by one. We consider a class of discrete systems with simple structure state matrix and with the eigenvectors structure such that condition number of their matrix is much greater than one.Method. The problem is solved with the use of vector-matrix formalism of state space method;for that reason the system is presented in vector-matrix form. Analytical assessments of processes in the system arefigured on the norm of state vectorfree motion with the calculation of the condition number of the state matrix eigenvectors matrix. Main Results. It has been found that the ill-conditioned eigenvectors structure of the state matrix may cause significant deviations of free motion trajectories from a monotone decreasing curve. Practical Relevance. These properties of the free motion of discrete systems trajectories are recommended for being kept under supervision, both in the design and the operational phases of systems.

The biotesting technique is described, concluded in valuation of рНchange, electrochemical redox potential and conductivity on a low-frequency alternating current samples, initially containing determined quantity of test microbes, incubated during a given time at given temperature in liquid medium of a given structure. We have submitted results of a given technique application to the analysis of influence on dynamics of growth and metabolic activity of Lactobacillus bulgaricus at various thermal and electrical factors. It is shown that after preliminary heating of L.bulg. during 10 minutes at 50ºС, vital activity of these microbes grows authentically and prolongably. While after similar heating at 60ºСthose activity reduces significantly. It is also shown that even unitary 60 minute action by a similar alternating electric field with an average intensity of 50 V/m at frequency of its change from 0.1 up to 3 Mc can significantly inhibit test microbial vital activity. The action by a similar electric field with frequency equal to 35 Mc, on the contrary, authentically and prolongably intensify those vital activity. Thus, it is shown that electrochemical biotesting is a sensitive laboratory tool, providing the researcher accessible, convenient and informative way for valuation of influence of various physico-chemical factors on a living body. It is also shown, that the imposing of external and not enough intensive electric fields in a combination with various modes of stress temperature processing is a perspective method for both suppression of harmful growth, and activation of vital activity of useful microflora (that can be useful, in particular, for efficiency increase of various medical and biotechnological processes).

Subject of Study. The paper deals withthermophysical properties of a new polydimethylsiloxane potting compound. We study the principles of thermal conductivity and heat capacity changing depending on composition of materials in the temperature range of 25-175 ° C. The search of optimal composition of the compound is carried out providing thermal conductivity not less than 0.5 W/(м·К) and data set for the change prediction of thermo-physical properties depending on a compound composition. Methods. All the samples were produced by FSUE “Institute of Synthetic Rubber” on the basis of polymers used in serial production. All the compounds are two- or three-component materials based on a low molecular weight (liquid) polydimethylsiloxane caoutchouc made by a cold solidification method. Polyethylsiloxane PES-5, aluminum hydroxide, TiN, boron, zinc oxide are used as additives. The research of thermal conductivity and heat capacity are carried out by meters λ-400 and С-400by dynamic method of monotonic warming. Main Results. We have obtained new experimental data about the thermal conductivity and heat capacity of the polysiloxane compound, depending on the temperature and the concentrations of various fillers. With increasing of the filler concentration the thermal conductivity of the samples increases as well and the heat capacity decreases. It is shown that with increasing of temperature the thermal conductivity of compounds is falling by about 15%, and the heat capacity increases by about 60-70%. Practical Relevance. The retrieved data give the possibility to find the optimal composition of compound material that guarantees the following operational properties: thermal conductivity not less than 0.5 W/(м·К), long thermostability in the temperature range of -60 - +200 °C, the density of hydrogen nucleus not less than 1∙1014 nucleus/cm2 and the summary absorbed gamma radiation dose up to 300 Gy. The developed compound is being tested and can be applicable in the development of neutron shielding for the transportation of the used nuclear fuel in the nuclear fuel containers.

Subject of Research. The paper deals with the models of computer networks represented by queuing systems with heterogeneous flow of requests. The models show processing and transmission of packets of different classes. Requirements for the quality indicators of packet transmission for each class are implemented by the use of the priority service disciplines. Operation in high load conditions is a distinctive feature of modern telecommunication systems, leading to probability increase of packets (requests) loss. This necessitates the use of models with limited memory capacity. Analytic study of such models is accompanied by complex and bulky mathematical calculations with explicit results only in special cases under certain assumptions. For example, with regard to the probability laws, describing the processes of receiving and serving of requests that limits the usage of such models. Method. The study of such systems with simulation methods is also problematic in view of statistical instability of operation characteristics for high load conditions. We propose an approach to the study of heavily loaded systems with priorities based on the models with unlimited memory capacity. Main Results. Analytical results for service characteristics with two moments of distribution were obtained. The distribution laws approximation of the number of requests in system is based on these results. Practical Relevance. We have  shown the possibility of approximation of continuous multi-exponential distributions that enable to assess memory capacity for given probability of losses for different classes of requests.             

The paper provides an overview of the watchdog mechanisms which are a category of technical solutions aimed at reliability improvement of embedded computing systems. The works presented in the foreign literature are mainly devoted to partial problems of watchdog mechanisms creation and application. The Russian-language sources are free of information, systematizing understanding of these mechanisms. Engineers’ lack of awareness in matters relating to these elements, important and difficult for integration into system, leads to their inefficient and even unskilled usage. This, in turn, can reduce reliability. The paper deals with a basic model that reflects operation principle of the watchdog mechanism. The analysis of technical solutions presented in literature and used for error detection was carried out. Their classification was proposed. The compact table form shows the main properties of these solutions. Review of solutions improving the efficiency of watchdog mechanisms was made. Today the most important problem is the lack of process automation tools which would give the possibility to integrate the watchdog mechanism effectively and correctly in projected hardware-software system in view of specified criteria (error detection time and response time). These questions are discussed in the final sections of this paper in form of setting targets for future research. The paper is addressed to researchers and developers concerned with embedded systems design and improvement of their operational reliability.

The paper deals with study of structure features of industrial products complex in instrument engineering and mechanical engineering as the most complicated type of products, characterized by highly branched and multi-level structure. We consider the product structure (assembly unit, kit, complex) in the form of a set of electronic design documents, containing its description. The increasing of products complexity leads to changes in interaction procedures between the developers at the stages of its life cycle, based on the use of data management systems (PDM – Product Data Management). We show that there are a variety of relationships (links) between the component parts of the product (including such complicated product as a complex), dependent on the availability of certain component parts (the structure of the complex). In this case the way of presenting information in the form of the product electronic structure is changed. Analysis of the relations between its structural composite parts based on research of the complex complexity is carried out; the features and ways of representing the electronic structure of the complex in a multi-level list and the graph are shown. We propose to distinguish the products included in the complex between complexing and auxiliary ones, characterized by the main, auxiliary, design or functional type of links. Implementation of the proposed approaches gives the possibility to solve problems of formation and submission of electronic design documentation by means of PDM-systems and to increase the level of interaction between contractors, subcontractors and customers when designing new products.

We have studied the question of data models creation with respect to the process-based management of industrial enterprise. It is proposed to use an object data model for management and operational management decision making systems at the process organization of industrial enterprise. We consider the basic concepts and definitions used in object-process data model, suggest its mathematical description, that includes tree representation of the system goals, object meta-models of production system, business process, the center responsible for resource. We have defined four phases of information system creation based on the object-process data model: goal tree description, metamodeling of objects and processes, data structure representation, data warehouse modeling of the production system. The goal tree is a hierarchical scorecard of the enterprise. Production objects are described by hierarchical structures and should meet requirements of the specified system of quality indicators for goods or services. The most important stage of material system metamodeling is to establish connections between objects, processes passing in it and indicators of the goals tree. The ultimate objective for metamodeling of the material system objects and processes should lie in the repository creation where one can get the structures of objects, processes, indicators and links on the basis of their unique identifiers. We have proposed a variant of object-process model application in integrated information systems based on the service-oriented architecture with the ability to take into account the goals of business, collect data on the current state of processes and organize data storage for retrospective data analysis tasks. The usage of object-process model during information system creation enables to combine two types of control: deviation control and management-by-objectives.

Subject of Research. The paper reviews the results of numerical simulation of the metal cylinder cooling process by the flow of gas-liquid medium moving horizontally along the surface of high-temperature metal cylinder in the annular channel. The results were obtained on the basis of a mathematical model for coupled heat transfer of gas-liquid medium and the metal cylinder in two-dimensional non-stationary formulation taking into account the axial symmetry of the cooling fluid flow relative to the longitudinal cylinder axis. Method. Control volume method is used for differential equation system solving. The flow field parameters are calculated by SIMPLE algorithm. The method of Gauss-Seidel with lower relaxation is used for the iterative solution of linear algebraic equations systems. Main Results. We have carried out verification of numerical simulation results with the results of analytical evaluation of length values for initial portions of hydrodynamic and thermal stabilization of the flow in the annular channel. We have obtained numerical results of heat transfer parameters at the cooling process of high temperature metal cylinder by gas-liquid flow with consideration for vaporization. The temperature values along the cylinder surface and radially have been defined while cooling by the cooling medium flow at a rate characteristic for laminar fluid flow. The intensity of surface temperature change of the metal cylinder is analyzed depending on the initial temperature, fluid flow rate and time of cooling process.

Subject of Study.The factors determining accuracy of computer simulation have been studied. Properties of the protective shielding housings of electrical and electronic devices have been analyzed under conditions of external high-intensity alternating electromagnetic field. The influence of this electromagnetic field has been studied, and the interrelationships between geometric, magnetic and electric parameters of the housings and their shielding properties have been shown. Authenticity estimation of the performed numerical analysis of the shielding properties is given. Method. Estimation and analysis of electromagnetic environment at the location of these devices at their development phase were carried out by computer finite element simulation method. And with this, qualitative and quantitative properties of shielding interaction with the housing were studied depending on the means of electromagnetic field definition, finite element mesh density, magnetic and electrical parameters of the housing material. Main Results. It is shown that there are at least three significant factors that directly effect on accuracy and authenticity of the finite element simulation results. These factors include: uniformity of specified unidirectional external electromagnetic field, density of the finite element mesh generation, authenticity of magnetic and electrical properties of magnetic materials used while making design of shielding housings. Practical Relevance.The results can be applicable in taking well-grounded decisions when designing the housings of electrical and electronic devices (like protective shielding housings for wide range of strength and frequency of the external high-intensity alternating electromagnetic field).

The paper presents analytical calculation and numerical simulation of fire, smoke and toxic gases spreading in the case of railways passenger train fire in a tunnelin view ofthe design features of certain types of Russian railway passenger cars and locomotives, the stages of the fire growth and the influence of various conditions on people safety in the tunnel. For a passenger train fire simulation we have used computational fluid dynamics model of fire-driven fluid flow based on solving a large-eddy simulation form of the Navier–Stokes equations appropriate for low-speed, thermally-driven flow with an emphasis on smoke and heat transport from fires, realized in the FDS program. The simulation results of various fire scenarios are given. The calculation of fire heat powerwas performedwith consideration for the properties of the flammable materials and design features of train cars and locomotives. The assessment of the provisioned people's safety was carried out. The results were applied in the design of railway tunnels in JSCS&R Design and Survey Institute "Lenmetrogiprotrans".

The paper deals with a possible solution to the problem of choosing the best variant of a simulation model from a finite set of alternatives in the process of decision-making support. Evaluation of possible solutions is carried out via methods of multi-criteria analysis of alternatives. The integration of simulation models and models of decision support is set-theoretically formalized. The problem of choosing the rational set of simulation model parameters, considering restrictions imposed by experts, is solved by heuristic optimization method based on the local search strategy. Developed algorithms and software form a separate module in the decision support system (DSS) "Space" that makes it possible to rank alternatives submitted by simulation models. DSS software architecture is developed by means of object-oriented paradigm and is built of C# and T-SQL code. Combined with client-server model via thin-client architecture it gives additional flexibility to the users due to their option preferences of hardware and software. DSS “Space” allows ranking of simulation results using both traditional methods, such as weight and multiplicative function, ideal value and fuzzy and hybrid models of user’s preferences identification.Designed software allows applying it for variable scientific and technical civil and military problems due to its universality.

Subject of Research. The paper deals with research of a damping system with elements having an ability to be linear work-hardening – work-hardening elements. This system transforms kinetic energy of moving progressively straightforward technical object into deformation energy and work of friction force. Example with element in the form of rigid-plastic conical shell is analyzed. Method. Research was carried out theoretically and was based on theory of thin shells and hypothesis of Kirchhoff-Love. In addition, Coulomb law modeling friction between both contact surfaces and Saint-Venant yield criterion are used. Main Results. Technique of strain-stress state examination in conical shell being deformed by rigid cone in view of friction force was generated. Practical Relevance. Results of research give the possibility to calculate strain-stress state of conical shell at indentation of rigid cone into it. These results open the door for future research of damping systems with plastic element in the form of a conical shell. 

This paper presents the results of developing of educational tools based on the information technology platform, that complements training materials with a new level of visualization through the use of cognitive visualization. Application of cognitive visualization for training materials is aimed at improving the learning activity, transition to a productive type of cognitive activity, formation of the desired competencies in students. The specific feature of the proposed approach to development of electronic educational tools is to shift a focus from an illustrative function of visual clarity tools to a cognitive function; formation of cognitive visual images of the objects of study, taking into account the physiological properties of the visual organ and human thinking; executing of concrete actions with the examinable object interactively. The principles that should be considered when designing electronic educational tools are formulated and justified as follows: content structuring of educational material; planning of learning results and development of training scenario; educational process adaptation to the individual student; use of interactive forms of interaction with a student; application of cognitive visualization methods. The possibility of Unity game engine usage to e-learning systems is shown; technology used enables to deploy applications on all main mobile, desktop, console platforms, as well as in the browser. "Internal combustion engine" is an example of interactive application developed with cognitive visualization in Microsoft Visual Studio environment with Unity game engine. The results of work can be recommended for the usage in the design of electronic educational tools aimed at achieving new educational results.

The paper presents results of navigation and control system development carried out without any information about the polygon map for mobile robot based on LEGO Mindstorms NXT. We have solved the problem of the robot movement to a point with given coordinates and obstacle avoidance. The robot is a two-engine platform with differential drive. To estimate the covered distance we use encoders on the motor shaft. The robot navigation is defined by the angular velocity measured by a gyroscope and calculated angle of rotation, and the distance to the obstacle is estimated by ultrasonic distance measurement. The obstacle avoidance problem is solved by the method of tangential escape. 

Subject of Research.The paper deals with duplicated computer system. Each node contains operational and test control. To improve the readiness of the system to implement the required functions, the test transition mode is valid only for one computer node. In addition to the functional and failed states of the system there are possible dangerous conditions not detected by the control malfunction of the nodes. The aim of this work is to define testing initialization optimal intervals that ensure the maximum probability of the system readiness for safety implementation of functional requests while minimizing downtime and delays in service. Method. Research method is based on creating a Markov model that gives the possibility to determine the probability of the system states and the impact of discipline and test control frequency initialization on the readiness of the system for safety operation. Main Results. We have shown the existence of optimal periodicity of test control, the one that produces the maximum probability of the system readiness for safety servicing of requests with delay minimizing of their stay in the system. Practical Relevance. The proposed models can be used in the selection of control disciplines and recovery of the safety operation of computer systems.