Результаты поиска по 'model of the function':
Найдено статей: 224
  1. Samoylenko I.A., Kuleshov I.V., Raigorodsky A.M.
    The model of two-level intergroup competition
    Computer Research and Modeling, 2023, v. 15, no. 2, pp. 355-368

    At the middle of the 2000-th, scientists studying the functioning of insect communities identified four basic patterns of the organizational structure of such communities. (i) Cooperation is more developed in groups with strong kinship. (ii) Cooperation in species with large colony sizes is often more developed than in species with small colony sizes. And small-sized colonies often exhibit greater internal reproductive conflict and less morphological and behavioral specialization. (iii) Within a single species, brood size (i. e., in a sense, efficiency) per capita usually decreases as colony size increases. (iv) Advanced cooperation tends to occur when resources are limited and intergroup competition is fierce. Thinking of the functioning of a group of organisms as a two-level competitive market in which individuals face the problem of allocating their energy between investment in intergroup competition and investment in intragroup competition, i. e., an internal struggle for the share of resources obtained through intergroup competition, we can compare such a biological situation with the economic phenomenon of “coopetition” — the cooperation of competing agents with the goal of later competitively dividing the resources won in consequence In the framework of economic researches the effects similar to (ii) — in the framework of large and small group competition the optimal strategy of large group would be complete squeezing out of the second group and monopolization of the market (i. e. large groups tend to act cooperatively) and (iii) — there are conditions, in which the size of the group has a negative impact on productivity of each of its individuals (this effect is called the paradox of group size or Ringelman effect). The general idea of modeling such effects is the idea of proportionality — each individual (an individual/rational agent) decides what share of his forces to invest in intergroup competition and what share to invest in intragroup competition. The group’s gain must be proportional to its total investment in competition, while the individual’s gain is proportional to its contribution to intra-group competition. Despite the prevalence of empirical observations, no gametheoretic model has yet been introduced in which the empirically observed effects can be confirmed. This paper proposes a model that eliminates the problems of previously existing ones and the simulation of Nash equilibrium states within the proposed model allows the above effects to be observed in numerical experiments.

  2. Minkevich I.G.
    The stoichiometry of metabolic pathways in the dynamics of cellular populations
    Computer Research and Modeling, 2011, v. 3, no. 4, pp. 455-475

    The problem has been considered, to what extent the kinetic models of cellular metabolism fit the matter which they describe. Foundations of stoichiometry of the whole metabolism and its large regions have been stated. A bioenergetic representation of stoichiometry based on a universal unit of chemical compound reductivity, viz., redoxon, has been described. Equations of mass-energy balance (bioenergetic variant of stoichiometry) have been derived for metabolic flows including those of protons possessing high electrochemical potential μH+, and high-energy compounds. Interrelations have been obtained which determine the biomass yield, rate of uptake of energy source for cell growth and other important physiological quantities as functions of biochemical characteristics of cellular energetics. The maximum biomass energy yield values have been calculated for different energy sources utilized by cells. These values coincide with those measured experimentally.

    Views (last year): 5. Citations: 1 (RSCI).
  3. Yakushevich L.V.
    Electronic analogue of DNA
    Computer Research and Modeling, 2017, v. 9, no. 5, pp. 789-798

    It is known that the internal mobility of DNA molecules plays an important role in the functioning of these molecules. This explains the great interest of researchers in studying the internal dynamics of DNA. Complexity, laboriousness and high cost of research in this field stimulate the search and creation of simpler physical analogues, convenient for simulating the various dynamic regimes possible in DNA. One of the directions of such a search is connected with the use of a mechanical analogue of DNA — a chain of coupled pendulums. In this model, pendulums imitate nitrous bases, horizontal thread on which pendulums are suspended, simulates a sugarphosphate chain, and gravitational field simulates a field induced by a second strand of DNA. Simplicity and visibility are the main advantages of the mechanical analogue. However, the model becomes too cumbersome in cases where it is necessary to simulate long (more than a thousand base pairs) DNA sequences. Another direction is associated with the use of an electronic analogue of the DNA molecule, which has no shortcomings of the mechanical model. In this paper, we investigate the possibility of using the Josephson line as an electronic analogue. We calculated the coefficients of the direct and indirect transformations for the simple case of a homogeneous, synthetic DNA, the sequence of which contains only adenines. The internal mobility of the DNA molecule was modeled by the sine-Gordon equation for angular vibrations of nitrous bases belonging to one of the two polynucleotide chains of DNA. The second polynucleotide chain was modeled as a certain average field in which these oscillations occur. We obtained the transformation, allowing the transition from DNA to an electronic analog in two ways. The first includes two stages: (1) the transition from DNA to the mechanical analogue (a chain of coupled pendulums) and (2) the transition from the mechanical analogue to the electronic one (the Josephson line). The second way is direct. It includes only one stage — a direct transition from DNA to the electronic analogue.

    Views (last year): 9.
  4. The paper develops a new mathematical method of the joint signal and noise calculation at the Rice statistical distribution based on combing the maximum likelihood method and the method of moments. The calculation of the sough-for values of signal and noise is implemented by processing the sampled measurements of the analyzed Rician signal’s amplitude. The explicit equations’ system has been obtained for required signal and noise parameters and the results of its numerical solution are provided confirming the efficiency of the proposed technique. It has been shown that solving the two-parameter task by means of the proposed technique does not lead to the increase of the volume of demanded calculative resources if compared with solving the task in one-parameter approximation. An analytical solution of the task has been obtained for the particular case of small value of the signal-to-noise ratio. The paper presents the investigation of the dependence of the sought for parameters estimation accuracy and dispersion on the quantity of measurements in experimental sample. According to the results of numerical experiments, the dispersion values of the estimated sought-for signal and noise parameters calculated by means of the proposed technique change in inverse proportion to the quantity of measurements in a sample. There has been implemented a comparison of the accuracy of the soughtfor Rician parameters’ estimation by means of the proposed technique and by earlier developed version of the method of moments. The problem having been considered in the paper is meaningful for the purposes of Rician data processing, in particular, at the systems of magnetic-resonance visualization, in devices of ultrasonic visualization, at optical signals’ analysis in range-measuring systems, at radar signals’ analysis, as well as at solving many other scientific and applied tasks that are adequately described by the Rice statistical model.

    Views (last year): 11.
  5. Orlov M.A., Kamzolova S.G., Ryasik A.A., Zykova E.A., Sorokin A.A.
    Stress-induced duplex destabilization (SIDD) profiles for T7 bacteriophage promoters
    Computer Research and Modeling, 2018, v. 10, no. 6, pp. 867-878

    The functioning of DNA regulatory regions rely primarily on their physicochemical and structural properties but not on nucleotide sequences, i.e. ‘genetic text’. The formers are responsible for coding of DNA-protein interactions that govern various regulatory events. One of the characteristics is SIDD (Stress-Induced Duplex Destabilization) that quantify DNA duplex region propensity to melt under the imposed superhelical stress. The duplex property has been shown to participate in activity of various regulatory regions. Here we employ the SIDD model to calculate melting probability profiles for T7 bacteriophage promoter sequences. The genome is characterized by small size (approximately 40 thousand nucleotides) and temporal organization of expression: at the first stage of infection early T7 DNA region is transcribed by the host cell RNA polymerase, later on in life cycle phage-specific RNA polymerase performs transcription of class II and class III genes regions. Differential recognition of a particular group of promoters by the enzyme cannot be solely explained by their nucleotide sequences, because of, among other reasons, it is fairly similar among most the promoters. At the same time SIDD profiles obtained vary significantly and are clearly separated into groups corresponding to functional promoter classes of T7 DNA. For example, early promoters are affected by the same maximally destabilized DNA duplex region located at the varying region of a particular promoter. class II promoters lack substantially destabilized regions close to transcription start sites. Class III promoters, in contrast, demonstrate characteristic melting probability maxima located in the near-downstream region in all cases. Therefore, the apparent differences among the promoter groups with exceptional textual similarity (class II and class III differ by only few singular substitutions) were established. This confirms the major impact of DNA primary structure on the duplex parameter as well as a need for a broad genetic context consideration. The differences in melting probability profiles obtained using SIDD model alongside with other DNA physicochemical properties appears to be involved in differential promoter recognition by RNA polymerases.

    Views (last year): 18.
  6. Malsagov M.X., Ougolnitsky G.A., Usov A.B.
    Struggle against economic corruption in resource allocation
    Computer Research and Modeling, 2019, v. 11, no. 1, pp. 173-185

    A dynamic game theoretic model of struggle against corruption in resource allocation is considered. It is supposed that the system of resource allocation includes one principal, one or several supervisors, and several agents. The relations between them are hierarchical: the principal influences to the supervisors, and they in turn exert influence on the agents. It is assumed that the supervisor can be corrupted. The agents propose bribes to the supervisor who in exchange allocates additional resources to them. It is also supposed that the principal is not corrupted and does not have her own purposes. The model is investigated from the point of view of the supervisor and the agents. From the point of view of agents a non-cooperative game arises with a set of Nash equilibria as a solution. The set is found analytically on the base of Pontryagin maximum principle for the specific class of model functions. From the point of view of the supervisor a hierarchical Germeyer game of the type Г2t is built, and the respective algorithm of its solution is proposed. The punishment strategy is found analytically, and the reward strategy is built numerically on the base of a discrete analogue of the initial continuous- time model. It is supposed that all agents can change their strategies in the same time instants only a finite number of times. Thus, the supervisor can maximize his objective function of many variables instead of maximization of the objective functional. A method of qualitatively representative scenarios is used for the solution. The idea of this method consists in that it is possible to choose a very small number of scenarios among all potential ones that represent all qualitatively different trajectories of the system dynamics. These scenarios differ in principle while all other scenarios yield no essentially new results. Then a complete enumeration of the qualitatively representative scenarios becomes possible. After that, the supervisor reports to the agents the rewardpunishment control mechanism.

    Views (last year): 33. Citations: 1 (RSCI).
  7. Ketova K.V., Romanovsky Y.M., Rusyak I.G.
    Mathematical modeling of the human capital dynamic
    Computer Research and Modeling, 2019, v. 11, no. 2, pp. 329-342

    In the conditions of the development of modern economy, human capital is one of the main factors of economic growth. The formation of human capital begins with the birth of a person and continues throughout life, so the value of human capital is inseparable from its carriers, which in turn makes it difficult to account for this factor. This has led to the fact that currently there are no generally accepted methods of calculating the value of human capital. There are only a few approaches to the measurement of human capital: the cost approach (by income or investment) and the index approach, of which the most well-known approach developed under the auspices of the UN.

    This paper presents the assigned task in conjunction with the task of demographic dynamics solved in the time-age plane, which allows to more fully take into account the temporary changes in the demographic structure on the dynamics of human capital.

    The task of demographic dynamics is posed within the framework of the Mac-Kendrick – von Foerster model on the basis of the equation of age structure dynamics. The form of distribution functions for births, deaths and migration of the population is determined on the basis of the available statistical information. The numerical solution of the problem is given. The analysis and forecast of demographic indicators are presented. The economic and mathematical model of human capital dynamics is formulated on the basis of the demographic dynamics problem. The problem of modeling the human capital dynamics considers three components of capital: educational, health and cultural (spiritual). Description of the evolution of human capital components uses an equation of the transfer equation type. Investments in human capital components are determined on the basis of budget expenditures and private expenditures, taking into account the characteristic time life cycle of demographic elements. A one-dimensional kinetic equation is used to predict the dynamics of the total human capital. The method of calculating the dynamics of this factor is given as a time function. The calculated data on the human capital dynamics are presented for the Russian Federation. As studies have shown, the value of human capital increased rapidly until 2008, in the future there was a period of stabilization, but after 2014 there is a negative dynamics of this value.

    Views (last year): 34.
  8. Ilyin O.V.
    The modeling of nonlinear pulse waves in elastic vessels using the Lattice Boltzmann method
    Computer Research and Modeling, 2019, v. 11, no. 4, pp. 707-722

    In the present paper the application of the kinetic methods to the blood flow problems in elastic vessels is studied. The Lattice Boltzmann (LB) kinetic equation is applied. This model describes the discretized in space and time dynamics of particles traveling in a one-dimensional Cartesian lattice. At the limit of the small times between collisions LB models describe hydrodynamic equations which are equivalent to the Navier – Stokes for compressible if the considered flow is slow (small Mach number). If one formally changes in the resulting hydrodynamic equations the variables corresponding to density and sound wave velocity by luminal area and pulse wave velocity then a well-known 1D equations for the blood flow motion in elastic vessels are obtained for a particular case of constant pulse wave speed.

    In reality the pulse wave velocity is a function of luminal area. Here an interesting analogy is observed: the equation of state (which defines sound wave velocity) becomes pressure-area relation. Thus, a generalization of the equation of state is needed. This procedure popular in the modeling of non-ideal gas and is performed using an introduction of a virtual force. This allows to model arbitrary pressure-area dependence in the resulting hemodynamic equations.

    Two test case problems are considered. In the first problem a propagation of a sole nonlinear pulse wave is studied in the case of the Laplace pressure-area response. In the second problem the pulse wave dynamics is considered for a vessel bifurcation. The results show good precision in comparison with the data from literature.

    Views (last year): 2.
  9. Grebenkin I.V., Alekseenko A.E., Gaivoronskiy N.A., Ignatov M.G., Kazennov A.M., Kozakov D.V., Kulagin A.P., Kholodov Y.A.
    Ensemble building and statistical mechanics methods for MHC-peptide binding prediction
    Computer Research and Modeling, 2020, v. 12, no. 6, pp. 1383-1395

    The proteins of the Major Histocompatibility Complex (MHC) play a key role in the functioning of the adaptive immune system, and the identification of peptides that bind to them is an important step in the development of vaccines and understanding the mechanisms of autoimmune diseases. Today, there are a number of methods for predicting the binding of a particular MHC allele to a peptide. One of the best such methods is NetMHCpan-4.0, which is based on an ensemble of artificial neural networks. This paper presents a methodology for qualitatively improving the underlying neural network underlying NetMHCpan-4.0. The proposed method uses the ensemble construction technique and adds as input an estimate of the Potts model taken from static mechanics, which is a generalization of the Ising model. In the general case, the model reflects the interaction of spins in the crystal lattice. Within the framework of the proposed method, the model is used to better represent the physical nature of the interaction of proteins included in the complex. To assess the interaction of the MHC + peptide complex, we use a two-dimensional Potts model with 20 states (corresponding to basic amino acids). Solving the inverse problem using data on experimentally confirmed interacting pairs, we obtain the values of the parameters of the Potts model, which we then use to evaluate a new pair of MHC + peptide, and supplement this value with the input data of the neural network. This approach, combined with the ensemble construction technique, allows for improved prediction accuracy, in terms of the positive predictive value (PPV) metric, compared to the baseline model.

  10. This article solves the problem of developing a technology for collecting initial data for building models for assessing the functional state of a person. This condition is assessed by the pupil response of a person to a change in illumination based on the pupillometry method. This method involves the collection and analysis of initial data (pupillograms), presented in the form of time series characterizing the dynamics of changes in the human pupils to a light impulse effect. The drawbacks of the traditional approach to the collection of initial data using the methods of computer vision and smoothing of time series are analyzed. Attention is focused on the importance of the quality of the initial data for the construction of adequate mathematical models. The need for manual marking of the iris and pupil circles is updated to improve the accuracy and quality of the initial data. The stages of the proposed technology for collecting initial data are described. An example of the obtained pupillogram is given, which has a smooth shape and does not contain outliers, noise, anomalies and missing values. Based on the presented technology, a software and hardware complex has been developed, which is a collection of special software with two main modules, and hardware implemented on the basis of a Raspberry Pi 4 Model B microcomputer, with peripheral equipment that implements the specified functionality. To evaluate the effectiveness of the developed technology, models of a single-layer perspetron and a collective of neural networks are used, for the construction of which the initial data on the functional state of intoxication of a person were used. The studies have shown that the use of manual marking of the initial data (in comparison with automatic methods of computer vision) leads to a decrease in the number of errors of the 1st and 2nd years of the kind and, accordingly, to an increase in the accuracy of assessing the functional state of a person. Thus, the presented technology for collecting initial data can be effectively used to build adequate models for assessing the functional state of a person by pupillary response to changes in illumination. The use of such models is relevant in solving individual problems of ensuring transport security, in particular, monitoring the functional state of drivers.

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