Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya最新文献

Beam dynamics simulation in the linear accelerator used as an injector for the 4th generation Specialized Synchrotron Radiation Source SSRS-4 第四代专用同步辐射源SSRS-4注入器直线加速器束流动力学模拟

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-06-02 DOI: 10.21638/11702/spbu10.2019.110

I. Ashanin, Yulia D. Kluchevskaia, A. A. Makhoro, Valeria Yu. Mechanikova, O. A. Mosolova, S. Polozov, A. Pronikov, V. Rashchikov

{"title":"Beam dynamics simulation in the linear accelerator used as an injector for the 4th generation Specialized Synchrotron Radiation Source SSRS-4","authors":"I. Ashanin, Yulia D. Kluchevskaia, A. A. Makhoro, Valeria Yu. Mechanikova, O. A. Mosolova, S. Polozov, A. Pronikov, V. Rashchikov","doi":"10.21638/11702/spbu10.2019.110","DOIUrl":"https://doi.org/10.21638/11702/spbu10.2019.110","url":null,"abstract":"At present, a fourth-generation synchrotron radiation source USSR (Synchrotron & Laser), which will the one of\u0000the world’s largest scientific centers is being designed in Russia. Its creation will make it possible to carry out\u0000experiments to study the structures of a wide range of objects in various disciplines at a qualitatively new level\u0000compared to the previous generation of sources. The overall facility layout includes a 6 GeV main storage ring\u0000and a linear electron accelerator (linac) at full energy. It is proposed to use one linear accelerator with two RF\u0000guns. A RF gun with a photocathode can be used to generate a bunch train for a Free Electron Laser (FEL), a\u0000RF gun with a thermionic cathode can be used for injection into a storage ring. Both injectors will operate with\u0000the same regular part of the linear accelerator, consisting of 100-120 identical sections. The purposed transverse\u0000emittance in the main storage ring will be 50–100 pm.rad. The development of a general linear accelerator\u0000scheme in order to minimize the beam energy spread and the output transverse emittance, the optimization of\u0000the geometric and electrodynamics parameters of the accelerating structures, and the beam dynamics analysis in\u0000this linear accelerator will be discussed in the article. The beam dynamics simulation was performed using the\u0000BEAMDULAC code developed at the Department of Electrophysical Facilities of the National Research Nuclear\u0000University MEPhI.","PeriodicalId":43738,"journal":{"name":"Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76982277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Network traffic anomalies automatic detection in DDoS attacks 网络流量异常自动检测DDoS攻击

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.210

Andrey V. Orekhov, Aleksey Orekhov

{"title":"Network traffic anomalies automatic detection in DDoS attacks","authors":"Andrey V. Orekhov, Aleksey Orekhov","doi":"10.21638/11701/spbu10.2023.210","DOIUrl":"https://doi.org/10.21638/11701/spbu10.2023.210","url":null,"abstract":"Distributed denial-of-service attacks (DDoS attacks) are intrusions into computing systems of the Internet. Their purpose is to make systems of the Internet inaccessible for users. DDoS attack consist of sending many requests to a certain resource at the same time. As a result, the server cannot withstand the network load. In such situation, a provider must determine the moment when attack begins and change the traffic management strategy. Detection of the beginning of a DDoS attack is possible by using unsupervised machine learning methods and sequential statistical analysis of network activity. To activate that, convenient to use mathematical models based on discrete random processes with monotonically increasing trajectories. Random functions, which are represented in the correspondence between generalized time and the cumulative sum of network traffic or the correspondence between the total number of incoming packets and the cumulative sum of packets processed, change their type of increasing from linear to non-linear. In the first case, to parabolic or exponential, in the second case to logarithmic or arctangent. To determine the moment when the type of increasing is going to change, one can use quadratic forms of approximation-estimation tests as statistical rules.","PeriodicalId":43738,"journal":{"name":"Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81340072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Finding the presence of borrowings in scientific works based on Markov chains 基于马尔可夫链发现科学作品中借用的存在

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.104

Rustam Saakyan, I. Shpekht, Gevorg A. Petrosyan

{"title":"Finding the presence of borrowings in scientific works based on Markov chains","authors":"Rustam Saakyan, I. Shpekht, Gevorg A. Petrosyan","doi":"10.21638/11701/spbu10.2023.104","DOIUrl":"https://doi.org/10.21638/11701/spbu10.2023.104","url":null,"abstract":"The study aims to develop optimal approaches to the search for borrowings in scientific works. The article discusses the stages of searching for the presence of borrowings, such as preprocessing, rough filtering of texts, searching for similar texts, and searching for borrowings. The main focus is on the description of approaches and techniques that can be effectively implemented at each stage. For example, for the preprocessing stage, it may be converting text characters from uppercase to lowercase, removing punctuation marks, and removing stop words. For the stage of rough text filtering, it is filters by topic and word frequency. It may be calculating the importance of words in the context of the text and representing the word as a vector in multidimensional space to determine the proximity measure for the stage of finding similar texts. Finally, it is a search for an exact match, paraphrases and a measure of similarity of expressions for the stage of finding borrowings. The scientific novelty lies in using Markov chains to find the similarity of texts for the second and third stages of the search for borrowings proposed by authors. As a result, the example shows the technique of using Markov chains for text representation, searching for the most frequently occurring words, building a graph of a Markov chain of words, and the prospects for using Markov chains of texts for rough filtering and searching for similar texts.","PeriodicalId":43738,"journal":{"name":"Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80732807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The method of penalty functions in the analysis of optimal control problems of Navier — Stokes evolutionary systems with a spatial variable in a network-like domain 罚函数法在类网络域具有空间变量的Navier - Stokes进化系统最优控制问题分析中的应用

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.203

Nataliya A. Zhabko, V. Karelin, V. Provotorov, S. Sergeev

{"title":"The method of penalty functions in the analysis of optimal control problems of Navier — Stokes evolutionary systems with a spatial variable in a network-like domain","authors":"Nataliya A. Zhabko, V. Karelin, V. Provotorov, S. Sergeev","doi":"10.21638/11701/spbu10.2023.203","DOIUrl":"https://doi.org/10.21638/11701/spbu10.2023.203","url":null,"abstract":"The article considers the Navier — Stokes evolutionary differential system used in the mathematical description of the evolutionary processes of transportation of various types of liquids through network or main pipelines. The Navier—Stokes system is considered in Sobolev spaces, the elements of which are functions with carriers on n-dimensional networklike domains. These domains are a totality of a finite number of mutually non-intersecting subdomains connected to each other by parts of the surfaces of their boundaries like a graph (in applications these are the places of branching of pipelines). Two main questions of analysis are discussed: the weak solvability of the initial boundary value problem of the Navier — Stokes system and the optimal control of this system. The main method of research of weak solutions is the semidigitization of the input system by a time variable, that is the reduction of a differential system to a differential-difference system, and using a priori estimates for weak solutions of boundary value problems to prove the theorem of the existence of a solution of the input differential system. For the optimal control problem a minimizing functional (the penalty function) and a family of the approximate functional with parameters that characterize the “penalty” for failure to fulfill the equations of state of the system are introduced. At the same time, a special Hilbert space is created, the elements of which are pairs of functions that describe the state of the system and controlling actions. The convergence of the sequence of such functions to the optimal state of the system and its corresponding optimal control is proved. The latter essentially widen the possibilities of analysis of stationary and nonstationary network-like processes of hydrodynamics and optimal control of these processesd.","PeriodicalId":43738,"journal":{"name":"Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84808114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Method for finding the cost-optimal road trajectory on the surface of the terrain 在地形表面上寻找成本最优道路轨迹的方法

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.201

M. Abbasov, A. S. Sharlay

引用次数: 0

Blade-like field cathode with a dielectric coating mathematical modeling 叶片状场阴极电介质涂层的数学建模

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.106

N. V. Egorov, E. Vinogradova, G. Doronin

引用次数: 0

Control and perturbation in Sturm — Liouville’s problem with discontinuous nonlinearity 不连续非线性Sturm - Liouville问题的控制与摄动

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.212

O. Baskov, D. Potapov

引用次数: 0

Razumikhin approach in the generalized Myshkis problem for systems with distributed delay 分布延迟系统广义Myshkis问题的Razumikhin方法

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.202

A. Egorov

引用次数: 1

Optimization approach to the design of nonlinear control system controllers 非线性控制系统控制器的优化设计方法

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.109

S. Zavadskiy, Dmitrii A. Ovsyannikov, Dmitrii D. Melnikov

{"title":"Optimization approach to the design of nonlinear control system controllers","authors":"S. Zavadskiy, Dmitrii A. Ovsyannikov, Dmitrii D. Melnikov","doi":"10.21638/11701/spbu10.2023.109","DOIUrl":"https://doi.org/10.21638/11701/spbu10.2023.109","url":null,"abstract":"The optimization approach is applied to the synthesis and optimization of nonlinear real-time feedback optimal control system of a certain Maglev platform. To optimize the nonlinear control law, the integral functional criteria is minimized, which evaluates the quality of the dynamics of not one trajectory, but an ensemble of nonlinear trajectories of the system. The considered ensemble of trajectories covers the entire area of the engineering gap between the platform and the guide rails. In this area the magnetic forces provide highly nonlinear effects due to the considered design features of the object. At the same time, it is required to provide the stabilization within the entire engineering gap. It makes this statement to be a multi-input nonlinear control problem. The components of the feedback control law vector have a polynomial form of the state-space variables. As a result of computational optimization of trajectories ensemble, a class of Pareto-optimal polynomial regulators is constructed for considered control object. In the presented set, each Pareto-optimal point corresponds to a specific designed controller and investigated functional criteria which evaluates the entire ensemble of perturbed nonlinear trajectories. This allows a research engineer to choose various nonlinear regulators and achieve a compromise between stabilization accuracy and energy costs.","PeriodicalId":43738,"journal":{"name":"Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76891728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research of investment attractiveness based on cluster analysis 基于聚类分析的投资吸引力研究

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Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya Pub Date : 2023-01-01 DOI: 10.21638/11701/spbu10.2023.206

D. Qi, V. Bure

{"title":"Research of investment attractiveness based on cluster analysis","authors":"D. Qi, V. Bure","doi":"10.21638/11701/spbu10.2023.206","DOIUrl":"https://doi.org/10.21638/11701/spbu10.2023.206","url":null,"abstract":"The continued economic development of various countries or regions has resulted in increased competition in global markets, leading to a concentration of investors and skilled labour in locations with high investment attractiveness. The investment attractiveness of a given country or region is determined by its investment potential and risk, which are characterized by a combination of various significant factors.This paper seeks to develop an econometric model to estimate the amount of investment in fixed capital in a specific region, taking into consideration the linear relationship between the observed results, in order to determine the main conditions that are necessary for achieving stable and high economic growth. These conditions include the acceleration of investment activity and the implementation of major national reforms to ensure the effectiveness of the investment process. To assess the overall influence of the financial and economic indicators studied on the volume of investment, multiple regression analysis was utilized as the primary mathematical tool of the study. Furthermore, assumptions were made regarding the rank of the observations. To validate this hypothesis, a cluster analysis was conducted, grouping the observations into four clusters based on their results, depending on the volume of investment or the geographical characteristics of the region.","PeriodicalId":43738,"journal":{"name":"Vestnik Sankt-Peterburgskogo Universiteta Seriya 10 Prikladnaya Matematika Informatika Protsessy Upravleniya","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86132852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0