Software & Systems

Articles of journal № 2 at 2014 year.

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11. Adjustment of the forging capd decision using the fuzzy set theory [№2 за 2014 год]
Authors: Kanyukov S.I., Konovalov A.V.
Visitors: 10448
The paper describes a new approach to creating the CAPD for press forging of shafts under uncertainty cond i-tions of the technological constraints boundaries imposed on the design parameters due to the i nsufficient formalization of the subject domain. As a result, the technological solutions related to the design process are various for different enterpri ses, and they are often ambiguous or even contradictory within one enterprise. The paper consideres two stages of the computer-aided design of the forging technology. At the first stage the design process is automated. All technological restrictions (in the base of the normative -reference information) are strictly impl e-mented. At the second stage the design is repeated. But this time the effects on the design parameter carried out by the user in active dialogue regime are taken into account. The paper pays special attention to the procedure of the design parameter co n-trol. The value of each parameter must belong to the specific technological interval with fuzzy boundaries. The novelty of the paper is the fact that the uncertainty of technological interval boundaries is formalized by the theory of fuzzy sets and fuzzy reasoning. The concept of membership function and quality criteria of designed process is input and filled with the physical meaning. Using the developed approach to creating forging CAPD allows increasing the work stability of the system in real pr o-duction conditions, giving a comparative evaluation of the quality of the received design decisions and facilitating signif i-cantly the implementation of the system in various enterprises.

12. Mathematical model for ship life cycle milestones cost assessment through information support systems [№2 за 2014 год]
Author: Tretyakov O.V.
Visitors: 12632
The programming stage plays the most significant role in ship design and construction because the whole range of activities at design and construction stages is carried out for this stage exactly. In conjunction with future opera tional processes design, their cost is defined, and different kinds of resources are planned in the budget. Mistakes in resource for e-casting may lead to funding shortages, failures to support ship readiness at a certain level and decrease the Navy operationa l potential. Conventional techniques for cost evaluation of separate stages of the ship life cycle are based on statistic relations. Such an approach requires regular technique and data updates according to ship design and operation findings. It is not a l-ways possible, especially when new ships operation experience is absent. Furthermore, it is quite challenging to assess (with acceptable error) the impact of ground-breaking decisions taken during ship design and construction on its operational cost using such techniques. The article describes a mathematical model of ship life cycle cost assessment based on activity-based costing analysis. The proposed approach not only enables to assess the ship cost based on the tasks cost, but also reveal the most vulnerable points in making design decisions. The model and its technique are designed for developing the ship life c y-cle information support system. The ship's structural and functional model is an information resource for calculations. And this model is based on the ship general digital model. This is one of the peculiarities of the said approach for cost assessment.

13. Network planning method for developing complex engineering systems [№2 за 2014 год]
Authors: Dopira R.V., Kordyukov R.Yu., Begletsov A.A., Sergienko S.V.
Visitors: 12908
The problem of developing a performance planning method for structural-complicated projects. These projects can also include development of complex engineering systems, such as weapons and military equipment, power engineering facilities, industry and transport facilities is formulated and formalized. A project is a set of operations necessary to ach ieve the purpose. The duration of every operation is known. They are conne cted by order relation (obligatory precedence). A tran-sition to a market economy and modifications in domestic and international situation with crisis developments in national economy have lead to a necessity of critical analysis of methods for maintening state requirements for production and new approaches to these problems solution. The proposed solution method is based on network planning method, on the idea of critical path optimisation. Known methods are improved based on the dynamic programming scheme . The critical path of the project graph defines performance time of the project. A cooperation of project performers is formed based on a solution of the assignment problem using a dynamic programming method and the offered algorithm, that allows consider ing the works precedence ratio defining project structure. Enterprise industrial engineering is based on rational combination of all basic, auxiliary and serving processes in time and space. Singularities and methods of this combination are вшааукуте in various working conditions. At the same time industrial engineering should be correspond to general principles. They are continuity, proportionality, rhythm, parallelism concern. The offered method allows implementing these principles.

14. The method of quality factors estimation for radar detection [№2 за 2014 год]
Authors: Platonov A.Yu., Pomazuev O.N., Mironov A.M., Abu-Abed, F.N., Ryumshin A.R.
Visitors: 14561
Nowadays stealth technologies are widely used. That is why the radiated radar -tracking signal is essentially r e-flected and absorbed. Thus, the power of a reflected signal on an intake radar entry is decreased. It complicates airplane d e-tection, or other object creat ed according to similar technology. Under these conditions it is difficult to estimate quality fa c-tors of radar detection of stealth and small targets. In many cases the radar signals amplitude and a phase is unknown parametres. The models of signals are u sed often when there are fast (in relation to clock frequency) fluctuations amplitude signals and a phase when there is no possibility to es ti-mate their values according to the results of preliminary statistical estimation on the previous intervals. We propose a technique which allows determining the quality of radar detection for a wide class of models of signals (i n-cluding stealth and small targets) in terms of stationary Gaussian noise, impulse noise and in non -jamming environment. The technique uses the obtained analytical expressions and approximation of distributions with Gram–Charlier series in Edge-worth Expansion. Detection threshold for given probabilities of false alarm is defined by Newton's method. It improves the accuracy and simplifies the calculations. The article shows the estimates for quality detection under these conditions. The de-veloped methodology and the resulting estimates can be used to determine quality factors of higher hierarchical level sys-tems. For example, indicators of secondar y signal processing, probability of signal detection (capture) in the search area.

15. Complex engineering systems development management [№2 за 2014 год]
Authors: Dopira R.V., Kordyukov R.Yu., Platonov A.Yu., Begletsov A.A., Sergienko S.V.
Visitors: 11484
When preparing and performing complex engineering systems projects it is necessary to consider uncertainty which can lead to failures of project planned implementation time. These failures are caused by increasing works duration. Therefore it is necessary to develop a management technique to minimize consequences of untimely and poor -quality per-formance. The basis of the proposed management technique is an earned value method. It includes making a project complete d e-scription and a detailed implementation schedule at an initial stage. It allows making estimation of the fact sheet and to s u-pervise the project from the beginning to the end of works. The technique consists of the following stages: planning, control an operational administration. The sequence of actions is following: scoping of works; responsibility distribution to control project implementation; making a directive project schedule; an estimation of an actual process of project implementation comparing with a directive schedule; cost -effectiveness evaluation; forecasting total actual project expenses based on an observed process of project implementation; management of works in progress; management of changes of a directive project schedule. The offered technique is quite simple in use and allows making real time decisions.

16. Modeling dynamic problems of thin-walled framework [№2 за 2014 год]
Author: Chernov S.A.
Visitors: 9334
The article describes the flexural and torsional vibrations of an open profile thin -walled rod with one cross section symmetry axis. When solving the rod vibrations problem the static task is considered with the addition of inertia forces, i.e . using the principle of Dalembert. The weight and stiffness of the rod are accepted as constant. Based on energy relatios the mass matrices are obtained in the explicit form of thin-walled rod finite elements that are in bending and torsion, and also a spatial finite element. The article shows comparative calculations on free and forced vibrations of П-shaped frame that is formed of rolled channel and double tee. The frame model uses beam finite and thin -walled rod elements, i.e., the flexural form of vibrations without considering torsion-al inertia of the rods and the torsional vibrations form respectively. There are values of the lower frequencies and corresponding modes from frames plane in the beam-column joint with free vibrations, as well as the maximum normal stresses in the profilecross -sections. The method of modeling is implemented in applications computer programs.

17. Human behavior simulation based on the subjective view of choice situation [№2 за 2014 год]
Author: Vinogradov G.P.
Visitors: 10215
The article considers a model of decision making based on subjective views on choice situation. The views are the result of cognitive activity. They ar e described in the form of a mental image as the result of perception. They are repr e-sented as a model of knowable and analyzed objects, processes, phenomena and are consciously accessible. Agent’s attitude to the observed and analyzed data is formed accor ding to the generated model and based on attitudes, rules, past experience, knowledge fixed in the consciousness. Then, depending on this relationship, a subject forms his behavior. He also develops his own program of actions in the events, phenomena that he considers important. A normative (rational) or behavioral deci-sion-making model is used to describe a decision-making process. Recent research of the decisions making theory has shifted from selection processes description (using normative models) to actual procedures of decision-making. These procedures use formalization of methods and approaches developed within cognitive psychology and information processing theory. The shift of the research emphasis is related to examination of the discrepancy reason s between actual and optimal choice. It is important to form the corresponding reflexive control. The proposed approach is based on agent’s choice simulation metho d-ology. This methodology is developed by extending classical decision-making models using formalisms concepts of psychol-ogy and sociology. The methodology involves description criteria for used terms and corresponding measures. The apparatus of fuzzy and rough sets is used to create these measures. Introduced measures can be assessed by observing the agent’s be-havior. The author introduces the definitions for functional properties that characterize the choice and behavior of the agen t. He also forms a selection model using subjective views on the choice situation.

18. Simulation of taxonomy program of parts production technology for mechanical-engineering using petri nets [№2 за 2014 год]
Author: Shestakov A.M.
Visitors: 11858
The article considers a model created using Petri nets. It allows analyzing the tran smission and receipt of data from computers to the technology taxonomy program for details production on the Internet. The purpose of modeling is simulation of the program failure, deadlocks search (no loops and dead ends), and identifying bottlenecks when transmiting data. In the simulation experiments failures of computer service by the taxonomy program are simulated as appearance of a random number of markers chips in the position. When there are no failures the program works automatically. The position serves the teams on the computer taxonomy. When there is an access denial in the program, the arc closes the transition and returns to the starting position. In normal operating mode at any time the Petri nets programs provide simultaneous conflict -free reference of multiple computers to taxonomy program with parallel work. Parallelism means that any of the computers that receive the access to the program can start referring or finish it before or after the other. The Petri nets apparatus c an be used as a formal language to describe the Web application model of taxonomy of the details production technologies. The Pe-tri nets are an extension of the classical graph theory. The Petri nets theory of enables the system specification using math e-matical representation. Its analysis helps to get important information about the structure and dynamic behavior of the mo d-eled system. Based on Petri nets the spanning tree of the reachability graph is constructed. Its points are all possible reac hable network marks. The analysis of the spanning tree highlightes its properties such as: security (number of marks in any position does not exceed 1); persistence (the inability of appearing and deleting resources in the simulated object) and vividness (no loops and dead ends.) The developed Petri net does not have loops and dead ends. Its taxonomy program can be used in production.

19. Modeling of the deformation process in the presence of a phase transition from a potential to dissipative stream [№2 за 2014 год]
Authors: Федотов В.П., Gorshkov A.V.
Visitors: 6128
The paper considers the algorithm for solving nonlinear elasticity issue. Cross-effect in complex systems is determined by the phenomenological components of relevant systems of equations. In these systems the relation between the generalized flows and generalized forces is established based on the Onsa ger’s ap-proach. For the deformation problems, this relation usually is established by Hook’s linear postulate. However, this postulat e can not be a basis for describing the second-kind phase transition from elasticity to dissipative plastic flow. And relating con-tinuous physical quantities (temperature, admixture concentration etc.) can not offset yield strength since the latter is an ex-perimental pointwise quantity. As a practically confirmed hypothesis, it is assumed that the reciprocity factors L km, constant by Onsager, can be nonline-ar functions. For deformation problems we use the Cauchy postulate. It states that the Onsager factor in the elastic region i s a quadratic function of strain. In this case the elasticity problem solution is reduced to the sol ution of nonlinear equation. The application of the finite elements method requires a solution of large -dimension systems and, consequently, it is extremely time-consuming. To reduce the computation time, the boundary element method is used in combination with analytical com-putation if possible. The article considers the example of the algorithm application to solve a nonlinear plane problem of el as-ticity for an inhomogeneous region.

20. On some inverse spectral problems for an arbitrary perturbation of the bi-harmonic operator with singular coefficients [№2 за 2014 год]
Author: Serov V.S.
Visitors: 5662
The classical inverse boundary spectral problem for any perturbation of the bi -harmonic operator with singular coefficients from some Sobolev spaces is considered. The problem is formulated as follows: Do the Dirichlet eigenvalues and some derivatives of the corresponding normalized eigenfunctions at the boundary of smooth bounded domai n uniquely determine the coefficients of this operator? We proved the first step of this problem, i.e. we proved that the Dirichlet eigenvalues and the derivatives up to the second order of the normalized eigenfunctions at the boundary uniquely determine t he so-called Dirichlet-to-Neumann map that corresponds to the Friedrichs self-adjoint extension of any perturbation of the bi-harmonic operator with singular coefficients. The main role in this proof is played by the existence of the Green’s function and its estimates up to the boundary of the domain. These facts will allow us to prove the classical Borg-Levinson theorem for the operators of fourth order of such type.

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