In this paper, we analyse a queueing system with two servers where the arrival and service proces... more In this paper, we analyse a queueing system with two servers where the arrival and service processes are interdependent. The evolution of these processes is governed by transitions on the product space of three Markov chains, which are descriptors of the arrival and service processes. The transitions in this Markov chain follow a semi-Markov rule and the exponential distribution governs the sojourn times in the states. The stability condition of the system is derived and the stationary distribution is calculated for the system in equilibrium. Several important performance measures are provided, and numerical illustrations of the model are presented.
Communications in computer and information science, 2016
This paper presents the description of the method of performance evaluation and assessment of mai... more This paper presents the description of the method of performance evaluation and assessment of main characteristics of broadband wireless networks with linear topology, which is based on a model of stochastic multiphase queueing systems with correlated MAP input flows and a cross-traffic. The results of analytical calculations for the networks of small dimension are given. A simulation model for assessment of performance characteristics of large-scale wireless networks with linear topology is developed.
Springer proceedings in mathematics & statistics, 2018
The problem of sensitivity of a redundant system’s reliability characteristics to shapes of their... more The problem of sensitivity of a redundant system’s reliability characteristics to shapes of their input distributions is considered. In Efrosinin and Rykov, Information Technologies and Mathematical Modelling, 2014, [1] an analytical form for dependence of a two-unit cold standby redundant system reliability characteristics on life and repair time input distributions was obtained and investigated for the case of exponential distribution of one of the time lengths. In the current chapter this study is extended with the help of simulation method to a general case of both non-exponential distributions. Comparison of analytic and simulation results was carried out.
In different spheres of human activity one needs to make decisions, connected with different risk... more In different spheres of human activity one needs to make decisions, connected with different risks, under condition of uncertainty. However, the very concept of uncertainty and risk needs clarification. The article discusses various interpretations of the term “uncertainty” and the formation of the term “risk” as a scientific concept. The authors prefer to limit themselves to the random-type uncertainty and propose to investigate risk and its management within the framework of this interpretation. As a tool for the problem solution construction and analysis of a risk tree is proposed. The proposed approach is demonstrated with the help of a real-world example.
This article presents a method of the automated control of distributed radio direction finding sy... more This article presents a method of the automated control of distributed radio direction finding system (RDFS) providing the construction of an automated system of technical diagnostics and recovery of distributed RDFS performance on the specified requirements. This dual-circuit method includes diagnosing and reliability operations, redundancy recommendations, and also control algorithms of the constituent elements of the system. The structure and mathematical apparatus of the operations, recommendations, and algorithms of the proposed method are shown. The basic requirements and restrictions under which the construction of automated technical diagnosis system is carried out are specified.
2020 International Conference Engineering and Telecommunication (En&T)
One of the promising directions in the framework of the concept of creating the next-generation 5... more One of the promising directions in the framework of the concept of creating the next-generation 5G/IMT-2020 networks is the development of broadband wireless networks based on autonomous unmanned aerial vehicles (UAVs). In addition to the interest in autonomous UAV-based high-altitude platforms (HAPs), leading researchers are currently engaged in the design and implementation of tethered unmanned HAPs, which are intended to be long-term operating and are widely used in civilian and military areas. Their possibility of long-term operation, which is one of the main advantages over autonomous UAVs, puts forward new reliability requirements. In this paper we study an analytical reliability model of the multi rotor flight module of the tethered HAP as a homogeneous hot-standby system consisting of $n$ elements operating in a random environment. A general Markov reliability model of the considered system operating in a random environment is proposed, which accounts for the increase in the functional load and the location of the failed components.
2015 Advances in Wireless and Optical Communications (RTUWO), 2015
A novel iterative algorithm for designing the architecture of broadband wireless networks along t... more A novel iterative algorithm for designing the architecture of broadband wireless networks along the long highways is considered. The mathematical problems were formulated and solved for every step of the iterative method. An example is given of designing a broadband wireless network along the highways in one of the regions of Russia.
We consider a distributed Radio Direction Finding System (RDFS) and the structure of its hardware... more We consider a distributed Radio Direction Finding System (RDFS) and the structure of its hardware. A classical diagnostic model of the distributed RDFS according to the binary criterion is presented, which includes diagnostic graphs and a set of tests. We propose a theoretical basis for diagnosing of the distributed RDFS according to the n-dimensional criterion. An example of implementation of the diagnostic approach to the distributed RDFS for states “failure”, “deterioration”, “normal” is presented.
In the actual study, we carried out a reliability analysis of a repairable redundant data transmi... more In the actual study, we carried out a reliability analysis of a repairable redundant data transmission system with the use of the elaborated mathematical and simulation model of a closed heterogeneous cold standby system. The system consists of one repair unit and two different data sources with an exponential cumulative distribution function (CDF) of their uptime and a general independent CDF of their repair time. We consider five special cases of the general independent CDF; including Gamma, Weibull-Gnedenko, Exponential, Lognormal and Pareto. We study the system-level reliability, defined as the steady-state probability (SSP) of failure-free system operation. The proposed analytical methodology made it possible to assess the reliability of the whole system in the event of failure of its components. Specific analytic expressions and asymptotic valuations are obtained for the steady-state probabilities of the system and the SSP of failure-free system operation. A simulation model o...
In this paper, we analyse a queueing system with two servers where the arrival and service proces... more In this paper, we analyse a queueing system with two servers where the arrival and service processes are interdependent. The evolution of these processes is governed by transitions on the product space of three Markov chains, which are descriptors of the arrival and service processes. The transitions in this Markov chain follow a semi-Markov rule and the exponential distribution governs the sojourn times in the states. The stability condition of the system is derived and the stationary distribution is calculated for the system in equilibrium. Several important performance measures are provided, and numerical illustrations of the model are presented.
Communications in computer and information science, 2016
This paper presents the description of the method of performance evaluation and assessment of mai... more This paper presents the description of the method of performance evaluation and assessment of main characteristics of broadband wireless networks with linear topology, which is based on a model of stochastic multiphase queueing systems with correlated MAP input flows and a cross-traffic. The results of analytical calculations for the networks of small dimension are given. A simulation model for assessment of performance characteristics of large-scale wireless networks with linear topology is developed.
Springer proceedings in mathematics & statistics, 2018
The problem of sensitivity of a redundant system’s reliability characteristics to shapes of their... more The problem of sensitivity of a redundant system’s reliability characteristics to shapes of their input distributions is considered. In Efrosinin and Rykov, Information Technologies and Mathematical Modelling, 2014, [1] an analytical form for dependence of a two-unit cold standby redundant system reliability characteristics on life and repair time input distributions was obtained and investigated for the case of exponential distribution of one of the time lengths. In the current chapter this study is extended with the help of simulation method to a general case of both non-exponential distributions. Comparison of analytic and simulation results was carried out.
In different spheres of human activity one needs to make decisions, connected with different risk... more In different spheres of human activity one needs to make decisions, connected with different risks, under condition of uncertainty. However, the very concept of uncertainty and risk needs clarification. The article discusses various interpretations of the term “uncertainty” and the formation of the term “risk” as a scientific concept. The authors prefer to limit themselves to the random-type uncertainty and propose to investigate risk and its management within the framework of this interpretation. As a tool for the problem solution construction and analysis of a risk tree is proposed. The proposed approach is demonstrated with the help of a real-world example.
This article presents a method of the automated control of distributed radio direction finding sy... more This article presents a method of the automated control of distributed radio direction finding system (RDFS) providing the construction of an automated system of technical diagnostics and recovery of distributed RDFS performance on the specified requirements. This dual-circuit method includes diagnosing and reliability operations, redundancy recommendations, and also control algorithms of the constituent elements of the system. The structure and mathematical apparatus of the operations, recommendations, and algorithms of the proposed method are shown. The basic requirements and restrictions under which the construction of automated technical diagnosis system is carried out are specified.
2020 International Conference Engineering and Telecommunication (En&T)
One of the promising directions in the framework of the concept of creating the next-generation 5... more One of the promising directions in the framework of the concept of creating the next-generation 5G/IMT-2020 networks is the development of broadband wireless networks based on autonomous unmanned aerial vehicles (UAVs). In addition to the interest in autonomous UAV-based high-altitude platforms (HAPs), leading researchers are currently engaged in the design and implementation of tethered unmanned HAPs, which are intended to be long-term operating and are widely used in civilian and military areas. Their possibility of long-term operation, which is one of the main advantages over autonomous UAVs, puts forward new reliability requirements. In this paper we study an analytical reliability model of the multi rotor flight module of the tethered HAP as a homogeneous hot-standby system consisting of $n$ elements operating in a random environment. A general Markov reliability model of the considered system operating in a random environment is proposed, which accounts for the increase in the functional load and the location of the failed components.
2015 Advances in Wireless and Optical Communications (RTUWO), 2015
A novel iterative algorithm for designing the architecture of broadband wireless networks along t... more A novel iterative algorithm for designing the architecture of broadband wireless networks along the long highways is considered. The mathematical problems were formulated and solved for every step of the iterative method. An example is given of designing a broadband wireless network along the highways in one of the regions of Russia.
We consider a distributed Radio Direction Finding System (RDFS) and the structure of its hardware... more We consider a distributed Radio Direction Finding System (RDFS) and the structure of its hardware. A classical diagnostic model of the distributed RDFS according to the binary criterion is presented, which includes diagnostic graphs and a set of tests. We propose a theoretical basis for diagnosing of the distributed RDFS according to the n-dimensional criterion. An example of implementation of the diagnostic approach to the distributed RDFS for states “failure”, “deterioration”, “normal” is presented.
In the actual study, we carried out a reliability analysis of a repairable redundant data transmi... more In the actual study, we carried out a reliability analysis of a repairable redundant data transmission system with the use of the elaborated mathematical and simulation model of a closed heterogeneous cold standby system. The system consists of one repair unit and two different data sources with an exponential cumulative distribution function (CDF) of their uptime and a general independent CDF of their repair time. We consider five special cases of the general independent CDF; including Gamma, Weibull-Gnedenko, Exponential, Lognormal and Pareto. We study the system-level reliability, defined as the steady-state probability (SSP) of failure-free system operation. The proposed analytical methodology made it possible to assess the reliability of the whole system in the event of failure of its components. Specific analytic expressions and asymptotic valuations are obtained for the steady-state probabilities of the system and the SSP of failure-free system operation. A simulation model o...
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Papers by Dmitry V . Kozyrev