The most popular constructions of cooling system pumps and the main mechanisms and reasons of pumps failures considered.
In this study, we investigated how scientific collaboration represented by co-authorship is related to citation indicators of a scientist. We use co-authorship network to explore the structure of scientific collaboration. For network construction, the profiles of scientists from various countries and scientific fields in Google Scholar were used. We ran the count data regression model for a sample of more than 30 thousand authors with the first citation after 2007 to analyze the correlation between co-authorship network parameters of scientists and their citation characteristics. We identify that there is a positive correlation between citation of scientist and number of his co-authors, between citation and the author’s closeness centrality, and between scholar’s citation and the average citation of his co-authors. Also, we reveal that h-index and i10-index are correlated significantly with the number of co-authors and average citation of co-authors. Based on these results, we can conclude that scientists who maintain more contacts and more active than others have better bibliometric indicators on an average.
If you want to make beautiful music,
you must play the black and the white notes together.
Richard M. Nixon, the 37th President of USA
The problem of studying the achievement of consensus in social groups is related to the complexity of organizing such a study, especially for large groups, with more than five participants. In connection with the above, it is advisable to investigate the phenomenon of consensus in large social groups, using the modeling methodology.
The article presents the results of statistical modeling describing the dependence of the time to reach consensus on the number and authoritarianism of a social group members using two mathematical models of consensus achievement in a group based on the model proposed by DeGroot and model of the cellular automaton.
The main problems of attaining consensus under the settings of the proposed model during the development of consensus standards in technical committees on standardization were analyzed. It is shown that an increase in the number of social group members and their authoritarianism has an adverse impact on the time for reaching consensus and increases the disunity of the group.
A model of the cellular automaton modeling the achievement of consensus within the negotiation process has been were studied: the initial discrepancy between the opinions of the members of the group and the space of opinions of the members of the group. In particular, it is shown that if initially the views of the members of the group are radically different, then the process of reaching consensus will be as long as possible if one of the participants is absolutely authoritative. If initially the views of the members of the group are close, then the process of reaching consensus will also be as long as possible if both members of the group are absolutely compromise.
The paper is devoted to the research of the controlled markov queueing model M/M/n*/N*. Research of income functional is carried out at control of several parameters. The control is based on the system structure. In the article the income functional is constructed on the trajectories of the controlled semi-markov process. The main problem is to search an optimal control strategy for the given model. The given research algorithm also can be used for various models at control with both discrete and continuous model parameters. Algorithmization of the problem is presented.
Linear theory methods of the coupled spacecharge waves for copropagating electron beams considering coefficients of electron interaction and a reduction of plasma oscillations are developed. Interaction of copropagating electron beams promising to amplification of microwaves in electron mode regimes to create devices of millimeter and submillimeter wavelength ranges. Equations of the coupled waves are written down and solutions of the dispersive equation in coupling regime of three and four waves are received. Large signal modes are investigated within model of large particles which has carried out the trajectory analysis of interaction processes of two copropagating electron beams with differ energy. Features of interaction modes with the gain and no gain waves are considered.
In the article there is a short literature overview of current trends in assessment of freight transportation performance, pointed out their’ advantages and disadvantages. The author has analyzed some foreign literature sources that allow saying about the complex attitude to the studied issue. Also there are concerned perspective methods of freight transportation assessment.
Equivalent systems method was implemented for designing the resonator slow-wave structures in plasma-beam devices, and non-impact plasma was used for the filling of the transit channel. The collation of the calculation results demonstrates the adequacy of the developed model in comparison with the real devices and structures. The analysis of the slow-wave structure dispersion characteristics was carried out. The structure of the plasma-beam travelling-wave tube high frequency unit was designed, and using the VEGA software, the tube parameters were estimated.
In this paper, the dispersion characteristics of slow-wave structures suitable for use in devices in the terahertz range are calculated. Slow-wave structures of “winding waveguide” and “counter pins” types can be considered as suitable systems. Analysis of dispersion characteristics of slow-wave structure was carried out by a waveguide-resonator model, which is built for the slow-wave structure of “winding waveguide”-type taking into account a channel for the electron beam. Waveguide-resonator model is consisted of quadripoles which describe the waveguide segments. This model is most accurately reflects the structure of the field in the winding waveguide. Dispersion characteristics were calculated according to the program stated in this paper. These characteristics are used to construct model of millimeter traveling-wave tube, which is in this case the chain of quadripoles. The most common in the solution of these problems is the discrete approach . The difference form of electrodynamic theory of excitation is used to justify the use of a mathematical model of the discrete interaction description .
In this study we use the crossing tree of a signal for the purpose of analysis of H-sssi processes. The crossing tree performs an ad-hoc decomposition of a signal adapted to its dynamics, and represents a natural tool for the analysis of its local fluctuations. We present here a new multifractal formalism and a novel approach for estimating the spectrum of singularities of H-sssi processes using the crossing-tree. The performance of the crossing-tree based method is demonstrated in a numerical study. Its performance is also compared with state-of-the-art techniques based on wavelets, including wavelet-leaders.
The increase of supply chains efficiency requires optimization of all types of logistic operations and functions. One of such functions is a choice of intermediaries (carriers, freight forwarders, suppliers, service enterprises etc.). The article discusses the analytical and expert approaches which serve as a basis to choose the intermediaries; along with it, in the article a comparative evaluation of choice expert methods is done: point-rating assessment, analytic hierarchy process and the general algorithm for selecting; the conclusions have been drawn about the applicability of each method
In this work, we analyze how the esports transfer market is organized with the help of mixed methods. We assume that a combination of Social Network Analysis and Machine Learning can help to achieve deeper understanding and to find patterns which are hidden from the one-side analysis. For the research, we gathered information about transfers of Dota 2 teams made between The Internationals of 2016 and 2017 and built a network based on this data. For the ERGM, we checked the importance of belonging to one region and organization, difference of skills, and participation in TI, and for association rules, on a par with the regions, we added players roles, and a metric of their personal performance -- fantasy points. Summing up the results, we found out the importance of homophily within regions, detected presence of vertical mobility, and discover the influence of the specific players roles.
The paper considers the use of alpha-distribution to analyze the influence of radiation on the reliability of command and measuring systems of the spacecraft. The financial support from the Government of the Russian Federation within the framework of the implementation of the 5-100 Programme Roadmap of the National Research University – Higher School of Economics is acknowledged.
This study (researchgrant No 15-05-0029) was supported by The National Research University–Higher School of Economics’
Academic FundProgramin 2015/2016.
This results are the preliminary first part of a presaccadic ERP study. The main goal of this study is an analysis of presaccadic brain potentials in connection of processes of saccadic eye movement preparation.
Cloud data storages are functioning in the presence of the risks of confidentiality, integrity, and availability related with the loss of information, denial of access for a long time, information leakage, conspiracy and technical failures. In this paper, we provide analysis of reliable, scalable, and confidential distributed data storage based on Multilevel Residue Number System (RNS) and Mignotte secret sharing scheme. We use real cloud providers and estimate characteristics such as the data redundancy, speed of data encoding, and decoding to cope with different user preferences. The analysis shows that the proposed storage scheme increases safety and reliability of traditional approaches and reduces data storage overheads by appropriate selection of RNS parameters.
The paper presents the analysis of the signal integrity in microstrip transmission line with nanoconducting dielectric. It shows the results of calculating the passage of a sequence of pulses of trapezoidal shape to account for losses in copper. It is due to its finite conductivity and skin effect, which significantly affects the high frequency harmonics, and also to the loss in nanoconducting dielectric with a high end-to-end conductivity. It is shown that all these losses are small and the use of nanoconducting dielectrics for eliminating electrostatic discharge is justified.
The importance of weak social ties in professional commu- nities is well studied and widely accepted. In our paper we analyze the structure of strong ties based on the co-authorship relation and use the formal concept analysis framework to figure out weak ties. The research is motivated by fast growing need in cross-disciplinary research, which re- quires experts from different areas to understand the bigger picture and identify potential fellows for collaborative research projects in nearest future.
Higher functionality of today’s electronic products demands high density integration of electronic components. In this field, printed-circuit-board (PCB) are the perspective technology to build a variety of electronic systems for different applications. Two types of boards were investigated: high current for power applications and high density boards for modern electronic equipment. The set of IR images and temperature-current diagrams for different substrate materials were investigated. Current and temperature limits for all test boards were defined to provide high level of board relectronic system reliability.