49 research outputs found

    Comparison of STS and ArchiMate Risk and Security Overlay

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    ArchiMate'i kasutatakse tänapäeval laialdaselt erinevates ärivaldkondades ettevõttesüsteemide arhitektuuri modelleerimiseks ning seda võib iseloomustada modelleerimise tööriistana, mis ühendab endas UML'i ja BPMN'i. STS keskendub aga sotsiotehnilisele perspektiivile ja tegijatevahelistele sotsiaalsetele vastastikmõjudele. Kuigi neil on palju ühist, on tegemist siiski erinevate lähenemistega, mistõttu räägitakse tänapäeval ArchiMate'st ja Secure Socio-Technical Systems'ist valdavalt kui eraldiseisvatest süsteemidest. Sellise olukorra tõttu on tekkinud puudujääk tööriistadest ja lähenemistest, mis ühendaks kaks süsteemi üheks uueks, mis võtaks arvesse nii modelleerimise arhitektuurseid kui ka sotsiotehnilisi aspekte. Selline kombinatsioon võib osutuda kasulikuks, kuna ArchiMate'ga saab modelleerida riskijuhtimist ja STS abil saab modelleerida erinevate süsteemi kaasatud tegijate omavahelist suhtlemist sotsiaalsest vaatevinklist ja turvalisuse inimfaktorit. Seega nende kahe süsteemi ühendamise teel võib luua turvalisuse modelleerimise lähenemise, mis katab nii arhitektuurilised kui sotsiaalsed vaatevinklid. Ideaalselt kasutaks selline lähenemine mõlema süsteemi tugevamaid külgi ja lahendaks mõned kitsaskohad. Lähenemise terviklikust hinnatakse ISSRM'i suhtes. Selles lõputöös kirjeldatakse ülalmainitud kombineeritud lähenemist turvalisuse modelleerimisele.Nowadays ArchiMate is widely used in enterprise architecture modelling of the various business domains and briefly could be described as something in between UML and BPMN with main focus in architectural perspective. STS in its turn is focusing on socio-technical perspective and taking into consideration social interactions betwen actors. Current state of the art is talking about Secure Socio-Technical Systems and ArchiMate separately. This is perfectly fine because this two approaches are quite different. Still, they have a lot in common. Based on the state described above problem could be identified as an absence of tools or approaches which will combine these two approaches into a new one, which will take into consideration both architectural and socio-technical perspectives of modelling. This combination could be beneficial because ArchiMate risk and security overlay models risk management and STS models how actors involved in this system interact with each other from social point of view and highlights “human factor” in security. Thus, combination of them could potentially result in security modelling approach which will cover both architecture and social points of view. Ideally, this approach will create some workarounds over weak places in both initial approaches and heavily use their best parts. We will also validate this approach in terms of completeness with respect to ISSRM. In this paper we will describe this combined approach

    Simulation of the Pneumatic System of a Seed Drill with a Vertical Flow Direction

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    The purpose of the work is to reveal the influence of conical directing agents on the speed and trajectory of particles movement in the vertical pneumatic conduit of the sowing machine and to establish their rational parameters. With the help of numerical modeling the particle flight trajectories in the air flow were obtained. The carried out researches have shown expediency of application of the conical directing agent, allowing to take away a longitudinal stream of particles from walls of a pneumatic conduit and to centre their trajectories of movement along an axis of a pneumatic conduit. Particles are focused to the center of the distributor when the distributor covers the area of pneumatic conduit cross-section close to 25%

    The experimental study of microclimatic conditions and factors of their formation in the oil mine

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    Patterns of formation of the thermal regime of the mine workings in oil mines are experimentaly studied. Results are described on example of oil mine No. 1 of the Oil Mine Control Unit Yareganeft of LUKOIL-Komi LLC. In the example given the thermal regime of mine workings is largely determined by the unique technology of oil extraction by the thermal mining method used in the Yaregskoye field of high-viscosity oil and involving the injection of superheated water vapor into the reservoir. That leads to subsequent heating of an oil reservoir and oil contained. Measurements of microclimatic parameters in mine workings (temperature, relative humidity, air velocity) were used to develop a computer model of the mine ventilation network in the AeroSet analytical complex and further analysis of the distribution of microclimatic parameters on this model. During the experimental survey the effectiveness of various mining engineering measures currently used at the oil mine and reducing the influence of the heavy thermal regime in the workings of oil mines was also investigated. The research conducted allowed to identify factors that form microclimatic conditions in various mine workings such as in the main air supply and ventilation workings, in the opening and development workings, and also in the process chambers. The most significant processes that caused nonstationarity of the thermal regime of the mine workings of the oil mine are described. Classification of these factors was carried out depending on the direction of their thermal effect, on the location of the source and on the final mechanism of heat transfer. Classification in terms of the microclimatic parameters of air in oil mine No. 1 presented in graphics is the main result of the work. This classification is the basis for the development of mathematical models of unsteady heat and mass transfer processes occurring in oil mines

    The influence of LED lighting on the development of Monarda L. in the conditions of hydroponics

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    The article presents the results of a study of the significance of the influence of the white and combined (red-blue-white) light spectrum on the growth and productivity of plants of the genus Monarda L. in the conditions of hydroponics. The optimal lighting mode has been found for the highest productivity of the monarda. A quantitative analysis of the content of photosynthetic pigments was carried out. The yield, leaf size and content of photosynthetic pigments in monarda leaves when grown under white LED lamps turned out to be higher than under colored ones

    Automated ventilation control in mines. Challenges, state of the art, areas for improvement

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    The article is divided into three main parts. The first part provides an overview of the existing literature on theoretical methods for calculating the optimal air distribution in mines according to the criteria of energy efficiency and providing all sections of mines with the required amount of air. It is shown that by the current moment there are many different formulations of the problem of searching the optimal air distribution, many different approaches and methods for optimizing air distribution have been developed. The case of a single (main) fan is most fully investigated, while for many fans a number of issues still remain unresolved. The second part is devoted to the review of existing methods and examples of the automated mine ventilation control systems implementation in Russia and abroad. Two of the most well-known concepts for the development of such systems are automated ventilation control systems (AVCS) in Russia and the CIS countries and Ventilation on demand (VOD) abroad. The main strategies of ventilation management in the framework of the AVCS and VOD concepts are described and also the key differences between them are shown. One of the key differences between AVCS and VOD today is the automatic determination of the operation parameters of fan units and ventilation doors using the optimal control algorithm, which is an integral part of the AVCS. The third part of the article describes the optimal control algorithm developed by the team of the Mining Institute of the Ural Branch of the Russian Academy of Sciences with the participation of the authors of the article. In this algorithm, the search for optimal air distribution is carried out by the system in a fully automated mode in real time using algorithms programmed into the microcontrollers of fans and ventilation doors. Minimization of energy consumption is achieved due to the most efficient selection of the fan speed and the rate of ventilation doors opening and also due to the air distribution shift control and the partial air recirculation systems introduction. It is noted that currently the available literature poorly covers the issue related to emergency operation modes ventilation systems of mines and also with the adaptation of automated control systems to different mining methods. According to the authors, further development of automated ventilation control systems should be carried out, in particular, in these two areas

    Josephson current and Andreev states in superconductor-half metal-superconductor heterostructures

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    We develop a detailed microscopic theory describing dc Josephson effect and Andreev bound states in superconducting junctions with a half-metal. In such systems the supercurrent is caused by triplet pairing states emerging due to spin-flip scattering at the interfaces between superconducting electrodes and the half-metal. For sufficiently clean metals we provide a detailed non-perturbative description of the Josephson current at arbitrary transmissions and spin-flip scattering parameters for both interfaces. Our analysis demonstrates that the behavior of both the Josephson current and Andreev bound states crucially depends on the strength of spin-flip scattering showing a rich variety of features which can be tested in future experiments.Comment: 12 pages, 7 figures; version published in Phys. Rev.

    Sample-dependent Dirac-point gap in MnBi2Te4 and its response to applied surface charge: A combined photoemission and ab initio study

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    Recently discovered intrinsic antiferromagnetic topological insulator MnBi2Te4 presents an exciting platform for realization of the quantum anomalous Hall effect and a number of related phenomena at elevated temperatures. An important characteristic making this material attractive for applications is its predicted large magnetic gap at the Dirac point (DP). However, while the early experimental measurements reported on large DP gaps, a number of recent studies claimed to observe a gapless dispersion of the MnBi2Te4 Dirac cone. Here, using micro(μ)-laser angle-resolved photoemission spectroscopy, we study the electronic structure of 15 different MnBi2Te4 samples, grown by two different chemists groups. Based on the careful energy distribution curves analysis, the DP gaps between 15 and 65 meV are observed, as measured below the Néel temperature at about 10–16 K. At that, roughly half of the studied samples show the DP gap of about 30 meV, while for a quarter of the samples the gaps are in the 50 to 60 meV range. Summarizing the results of both our and other groups, in the currently available MnBi2Te4 samples the DP gap can acquire an arbitrary value between a few and several tens of meV. Furthermore, based on the density functional theory, we discuss a possible factor that might contribute to the reduction of the DP gap size, which is the excess surface charge that can appear due to various defects in surface region. We demonstrate that the DP gap is influenced by the applied surface charge and even can be closed, which can be taken advantage of to tune the MnBi2Te4 DP gap size.The authors acknowledge support by the Saint Petersburg State University Grant No. ID 73028629, Russian Science Foundation Grant No. 18-12-00062 in part of the photoemission measurements and total analysis of the results, Grant No. 18-12-00169-p in part of the electronic band structure calculations and Grant No. 20-42-08002 in part of analysis of magnetic properties and Science Development Foundation under the President of the Republic of Azerbaijan Grant No. EI F-BGM-4-RFTF1/2017-21/04/1-M-02. M.M.O. acknowledges the support by Spanish Ministerio de Ciencia e Innovación (Grant No. PID2019-103910GB-I00). K.K. and O.E.T. acknowledge the support from state assignment of IGM SB RAS and ISP SB RAS.Peer reviewe

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at s=8TeV\sqrt{s}=8\,\mathrm TeV{} with the ATLAS detector

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