T-Comm最新文献

{"title":"Using two-dimensional fast Fourier transform for estimating spectral correlation function","authors":"T. Shevgunov, Oksana A. Gushchina","doi":"10.36724/2072-8735-2021-15-11-54-60","DOIUrl":"https://doi.org/10.36724/2072-8735-2021-15-11-54-60","url":null,"abstract":"The paper presents the algorithm for estimating spectral correlation function (SCF) of a wide-sense cyclostationary random process. SCF provides the quantitative representation of the correlation in frequency domain and relates to cyclic autocorrelation function via Fourier transform. The algorithm is based on two-dimensional Fourier transform, which is being applied to the discrete diadic correlation function weighted by a two-dimensional windowing function, chosen rectangular in the direction orthogonal to the current-time axis. This transform can be implemented by means of the fast Fourier transform (FFT) algorithm, which is built-in in a variety of modern mathematical platforms. A pulse-amplitude modulated process masked by the additive stationary Gaussian noise was considered as an example of a random process exhibiting strong cyclostationarity. The numerical simulation where the estimation of spectral correlation function of such process is conducted, and it proved the effectiveness of the proposed algorithm.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121847166","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}

{"title":"METHODOLOGY FOR CALCULATING THE ECONOMIC EFFICIENCY OF CONNECTING END-USERS OF MESH WIRELESS NETWORKS TO THE GLOBAL NETWORK","authors":"Evgeniy V. Danko, Olga V. Konstantunova, O. Ternovoy","doi":"10.36724/2072-8735-2021-15-2-20-25","DOIUrl":"https://doi.org/10.36724/2072-8735-2021-15-2-20-25","url":null,"abstract":"This paper explores the cost-effectiveness of various ways to connect users to the Internet. Three methods are analyzed: cable connection, GSM connection and Wi-Fi mesh connection. For these methods, a mathematical model is constructed that allows you to evaluate: return on investment, company profits, risk fear ratios and regrets about lost profits. The indicated calculations are carried out for 100 users in each connection method. The study of economic efficiency will be carried out by assessing the values of the parameters NPV, PI and IRR. According to the classical approach to assessing the effectiveness of projects, when implementing projects in cities, a connection using Wi-Fi mesh networks has higher relative project performance indicators (PI and IRR), but a lower NPV indicator than a project for a cable connection to the Internet. In conditions of low population density, the project for the implementation of the Internet by Wi-Fi mesh networks is more profitable in all considered indicators (NPV, PI, IRR) than the project for the implementation of the Internet via cellular communication.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121038449","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}

{"title":"MULTI-OBJECTIVE OPTIMIZATION OF VIRTUAL MACHINE PLACEMENT ON PHYSICAL SERVERS IN CLOUD DATA CENTERS","authors":"A. Toutov, N. Toutova, A. Vorozhtsov, I. A. Andreev","doi":"10.36724/2072-8735-2021-15-1-28-34","DOIUrl":"https://doi.org/10.36724/2072-8735-2021-15-1-28-34","url":null,"abstract":"The problem of virtual machine placement on physical servers in cloud data centers is considered. The resource management system has a two-level architecture consisting of global and local controllers. Local controllers analyze the state of the physical servers on which they are located and determine possible underloading, overloading, and overheating states based on the forecast for the next observation window. If one of the listed states is detected, the local controller notifies the global controller, which selects the destination servers to host the virtual machines via migration. It is proposed to place virtual machines based on the criteria of minimum remaining unused resources and violation of SLA agreements. A mathematical formulation of the optimization problem is given, which is equivalent to the known main assignment problem in terms of structure, necessary conditions, and the nature of variables. Reducing the assignment problem to a closed transport problem allowed us to solve the problem of hosting virtual machines under many criteria in real time and significantly increase its dimension in comparison with heuristic algorithms, which makes it possible to maintain the quality of modern cloud services in the conditions of rapid growth of physical and virtual resources of data centers. The developed mathematical formulation of the problem and the results of computational experiments can be included in the mathematical software of virtual machine live migration.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125469574","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}

{"title":"Development of risk management theory","authors":"E. Maksimova, V. Shmal","doi":"10.36724/2072-8735-2022-16-2-39-46","DOIUrl":"https://doi.org/10.36724/2072-8735-2022-16-2-39-46","url":null,"abstract":"The issues of developing a risk assessment in the field of functional traffic safety for the Central Directorate of Traffic Control (CD), Central Directorate of Infrastructure, Directorate of Traction and Transenergo are considered. assessment of risks associated with violation of traffic safety rules and operation of railway transport on the responsibility of traffic control centers (DCC). The general theory of risk management in various areas of the economy and industry, the methods for identifying factors affecting risk, the formation of a risk register and risk management strategies, taking into account the possible costs of eliminating the possibility of risk triggering and financial losses from possible negative events, are described. A brief historical background on the development of risk management theory is given. The issues of developing methodological approaches to assessing risks in the field of functional safety of railway train traffic for the Central Directorate of Traffic Control (CD), the Central Directorate of Infrastructure, the Directorate of Traction and Transenergo are considered.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121516926","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}

{"title":"SOME PROPERTIES OF RESONANT TRANSPARENCY PEAKS IN THE FORMATION OF A CHAIN OF BARRIERS","authors":"A. P. Zhilinsky, V. Degtyarev","doi":"10.36724/2072-8735-2021-15-5-46-51","DOIUrl":"https://doi.org/10.36724/2072-8735-2021-15-5-46-51","url":null,"abstract":"Some features of the energy spectrum and wave functions of microparticles in the chain of potential barriers are considered. The structure under consideration is a sequence of rectangular potential wells and barriers through which the particle moves. As is known, when such a chain is formed, resonant levels arise in the link, for which the transparency of the system is equal to one. As the number of links increases, these levels and the corresponding wave functions undergo a significant rearrangement. These levels are split into close sublevels, the energy of which depends on the parameters of the barriers and the number of links in the chain. The q-factor of the resulting levels and its dependence on the characteristics of the chain are determined. The dependence of the wave function on the chain parameters is investigated. It is shown that there is a certain analogy between quantum tunneling of particles through a system of barriers and propagation of electromagnetic waves through electric filters. The features of resonant phenomena in these systems are discussed. The developed concepts can be used in nanoelectronics in the development and construction of new devices based on quantum tunneling effects, as well as in the study of relevant sections of the physics course in higher Education institutions.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120956250","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}

{"title":"ANALYSIS OF THE INFLUENCE OF MACHINE LEARNING ALGORITHM PARAMETERS ON THE RESULTS OF TRAFFIC CLASSIFICATION IN REAL TIME","authors":"I. Krasnova","doi":"10.36724/2072-8735-2021-15-9-24-35","DOIUrl":"https://doi.org/10.36724/2072-8735-2021-15-9-24-35","url":null,"abstract":"The paper analyzes the impact of setting the parameters of Machine Learning algorithms on the results of traffic classification in real-time. The Random Forest and XGBoost algorithms are considered. A brief description of the work of both methods and methods for evaluating the results of classification is given. Experimental studies are conducted on a database obtained on a real network, separately for TCP and UDP flows. In order for the results of the study to be used in real time, a special feature matrix is created based on the first 15 packets of the flow. The main parameters of the Random Forest (RF) algorithm for configuration are the number of trees, the partition criterion used, the maximum number of features for constructing the partition function, the depth of the tree, and the minimum number of samples in the node and in the leaf. For XGBoost, the number of trees, the depth of the tree, the minimum number of samples in the leaf, for features, and the percentage of samples needed to build the tree are taken. Increasing the number of trees leads to an increase in accuracy to a certain value, but as shown in the article, it is important to make sure that the model is not overfitted. To combat overfitting, the remaining parameters of the trees are used. In the data set under study, by eliminating overfitting, it was possible to achieve an increase in classification accuracy for individual applications by 11-12% for Random Forest and by 12-19% for XGBoost. The results show that setting the parameters is a very important step in building a traffic classification model, because it helps to combat overfitting and significantly increases the accuracy of the algorithm’s predictions. In addition, it was shown that if the parameters are properly configured, XGBoost, which is not very popular in traffic classification works, becomes a competitive algorithm and shows better results compared to the widespread Random Forest.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129036907","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}

{"title":"OBSERVATION SYSTEM RESOURCE PLANNING IN PRESENCE OF ACCESS CONTROL BASED ON VOLUME OF RESOURCE OCCUPIED BY TRAFFIC FLOWS","authors":"U. Andrabi, M. G. Kanishcheva, S. Stepanov","doi":"10.36724/2072-8735-2022-16-8-54-62","DOIUrl":"https://doi.org/10.36724/2072-8735-2022-16-8-54-62","url":null,"abstract":"Due to various recent improvements in cellular technology, communication networks now offer information flows with a wide range of transmission speed and service quality characteristics. These characteristics are more highly noticeable in intelligent networks, particularly when IoT technology is used. Regulation and high-quality transmission of such massive volumes of data present severe issues among virtual operators engaged in the communications sector and utilizing cellular network infrastructure to provide video surveillance services for its consumers. Unfortunately, no single approach exists that enables the execution of high-quality incoming traffic flow maintenance and the allocation of information transmission resources in diverse networks. One of the methods to address these issues is mathematical modelling, which takes into consideration the unique characteristics of traffic flows that emerge and are approved for servicing. Our work addresses this problem by designing a resource allocation strategy for an isolated LTE network cell with heterogeneous traffic flows while sharing its radio resources. Traffic sources considered are operator surveillance system's video cameras that use cellular network infrastructure to deliver data to analytical centers. A mathematical model is used to study the process of sharing a resource, which takes into consideration the priority of real-time traffic, the elasticity property during file transfer, and the access restriction for all threads, based on the quantity of resource held by each thread. When sharing the resources of an isolated LTE network cell with heterogeneous traffic flows. Traffic sources are surveillance system operators' video cameras that use cellular network infrastructure to deliver data to analysis centers. Algorithms for evaluating the characteristics of the service of applications are constructed and the dependence of the characteristics on the restriction of access is investigated. Using the developed model, a scenario of dynamic distribution of the access node resource between incoming sessions has been developed, which allows creating conditions for differentiated servicing of heterogeneous traffic flows based on access restrictions and resource loading by each of the considered flows.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133745664","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}

{"title":"Combiners/dividers systems of solid-state transmitting devices of modern radar systems","authors":"A. S. Pshenichkin, Pjsc, A. Suchkov, Almaz R P Corp., Pjsc Almaz R P Corp.","doi":"10.36724/2072-8735-2020-14-12-33-44","DOIUrl":"https://doi.org/10.36724/2072-8735-2020-14-12-33-44","url":null,"abstract":"One of the most important components of the radar system, which determines its potential characteristics, is the transmitting device. It is known that the advantage of constructing transmitting devices based on the principle of coherent summation of the power of solid-state amplifier modules is that they allow obtaining the required output power level and ensuring the operation of the radar in the \"smooth failure\" mode with the possibility of prompt replacement of faulty amplifier modules during operation. At the same time, an urgent task is to increase the output power level of the transmitting device by reducing losses in its microwave path, caused by the spread of the amplitudes and phases of the summed signals. This article provides a brief overview of materials from open Russian and foreign sources on methods for summing the power of microwave oscillations, as well as possible ways to implement combiners/dividers of power of solid-state amplifying modules, on the basis of which the output stages of transmitting devices of modern radar systems are built. The advantages and disadvantages of Wilkinson combiners, waveguide traveling wave combiners, as well as problems arising in their development are discussed. The main issues related to increasing the efficiency when summing the power of several amplifying modules of the same type of the transmitting device are considered. It is shown that the choice of the summation/division scheme and its constructive implementation are determined by the range of operating frequencies, the output pulse and average power of the transmitting device, and the permissible weight and dimensions. The rationality of methods for obtaining the required output power in each specific case is analyzed, including the most promising ones based on special correction schemes that reduce the phase errors of the distribution-summing system.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116696468","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}

{"title":"HARMONIC BALANCE THEORY FOR SCHEME TECHNICAL DESIGN","authors":"S. F. Gorgadze, A. A. Maximov","doi":"10.36724/2072-8735-2020-14-11-21-32","DOIUrl":"https://doi.org/10.36724/2072-8735-2020-14-11-21-32","url":null,"abstract":"The analysis and generalization of the main publications on the methods of synthesis and analysis of non-linear active microwave circuits based on the use of the harmonic balance method are presented. As a result of some classification of mathematical approaches and techniques used in the context of this method, a selection and review of basic algorithms was made, the sequential application of which makes it possible to obtain the final result for a scheme of any complexity. The principles of drawing up the initial system of differential equations for electronic circuits and reducing it to a system of linear algebraic equations are considered. A detailed and, at the same time, simplified interpretation of the approaches involving the use of projection methods and Krylov subspaces is given in order to make them easier to understand. Both the complete and the restart generalized method of minimal residuals are considered, in which the desired solution is obtained in the course of an iterative process, at each stage of which subspaces of lower dimension are constructed. The possibilities of simulators and application packages intended for circuit design of electronic circuits are considered. The problem of matching a power amplifier in large signal mode using the APLAC simulator, which is NI AWR technology for designing high-frequency circuits, is discussed.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131572669","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}

{"title":"QUEUE ANALYSIS IN THE G/G/1 SYSTEM BASED ON HYPEREXPONENTIAL DISTRIBUTIONS","authors":"M. Buranova","doi":"10.36724/2072-8735-2021-15-8-36-43","DOIUrl":"https://doi.org/10.36724/2072-8735-2021-15-8-36-43","url":null,"abstract":"For real-time applications, the change in packet delay, which is usually called delay jitter, is one of the most important parameters of quality of service in modern infocommunication networks when processing multimedia streams, along with the delay and the probability of packet loss. This article discusses approaches to assessing jitter in modern infocommunication networks when processing non-Poissonian traffic in the G/G/1 system. To approximate the system of an arbitrary queue G/G/1, a model based on hyperexponential distributions of the type H2/H2/1 was used. As a processed stream, the implementation of IP network traffic with the absence of mutual correlations between the time intervals between packets and the times of packet processing is used. An important task in this case is to determine the parameters of hyperexponential distributions for the time intervals between packets and packet processing times. The paper presents two methods for determining the parameters of hyperexponential distributions: using the method of moments and using the EM-algorithm. The paper analyzes the influence of the network load factor on the jitter value when using two models for determining the parameters of hyperexponential distributions. This analysis showed a slight increase in jitter with increasing network load both in the case of using the method of moments and in the case of the EM algorithm. It has been determined that the estimates of the jitter values in the case of applying the method of moments and the EM algorithm are quite close in value. The main result of the work is to obtain simple calculation formulas for the analysis of jitter in the G/G/1 system using hyperexponential distributions.","PeriodicalId":263691,"journal":{"name":"T-Comm","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132726203","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}