Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631254
P. Cika, S. Grabovsky, V. Zeman, V. Clupek
This article deals with development of a network emulator of transmission parameters of data networks working with the TCP/IP protocol suite. The article contains a specification of transmission parameters of data networks and a specification of currently developed open-source systems, which can be used to emulate transmission parameters of data networks. Further, the design and implementation of the network emulator is described. The proposed network emulator uses Traffic Control, NetEm, iptables, web service and Apache JMeter. The graphical user interface (GUI) of the network emulator is implemented by a web service and a module to the GUI of the stress tester Apache JMeter. The article also deals with measurement of transmission parameters of data networks using the developed network emulator and the Station A and Station B. The measured values are discussed.
{"title":"Network Emulator of Transmission Parameters of Data Networks","authors":"P. Cika, S. Grabovsky, V. Zeman, V. Clupek","doi":"10.1109/ICUMT.2018.8631254","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631254","url":null,"abstract":"This article deals with development of a network emulator of transmission parameters of data networks working with the TCP/IP protocol suite. The article contains a specification of transmission parameters of data networks and a specification of currently developed open-source systems, which can be used to emulate transmission parameters of data networks. Further, the design and implementation of the network emulator is described. The proposed network emulator uses Traffic Control, NetEm, iptables, web service and Apache JMeter. The graphical user interface (GUI) of the network emulator is implemented by a web service and a module to the GUI of the stress tester Apache JMeter. The article also deals with measurement of transmission parameters of data networks using the developed network emulator and the Station A and Station B. The measured values are discussed.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129777483","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631243
A. Ovsyannikova, S. Zavjalov, S. Volvenko
In this work the joint use of turbo codes and optimal signals is considered. Due to high spectral efficiency provided by optimal signals and improved energy efficiency caused by turbo coding it is possible to get closer to the Shannon limit. The degree of approaching is defined as the minimal distance between the Shannon curve and the point which coordinates are values of spectral and energy efficiency. The results are also compared to “classic” BPSK signals. It is shown that optimal signals with turbo coding are 7.6 times closer to the Shannon limit than “classic” BPSK signals for the same data rate. Parameters of signals with better approaching to the Shannon limit are found.
{"title":"On the Joint Use of Turbo codes and Optimal Signals with Increased Symbol Rate","authors":"A. Ovsyannikova, S. Zavjalov, S. Volvenko","doi":"10.1109/ICUMT.2018.8631243","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631243","url":null,"abstract":"In this work the joint use of turbo codes and optimal signals is considered. Due to high spectral efficiency provided by optimal signals and improved energy efficiency caused by turbo coding it is possible to get closer to the Shannon limit. The degree of approaching is defined as the minimal distance between the Shannon curve and the point which coordinates are values of spectral and energy efficiency. The results are also compared to “classic” BPSK signals. It is shown that optimal signals with turbo coding are 7.6 times closer to the Shannon limit than “classic” BPSK signals for the same data rate. Parameters of signals with better approaching to the Shannon limit are found.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"202 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114734722","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631269
Leonid A. Sevastianov, Sergey A. Vasilyev
Telecommunication and IT companies are looking forward to the implementation of 5G technology. The driving factors of this technology is aggregation of computing and networking resources. The 5G services will be more complicated than usual online services not only in technological methods, but also from an economic problems: fast service development, productive utilization of networks resources, dynamic adjustment to real market demand are all direct benefits of the integration 5G infrastructure. In this paper we study the economic mutual influence between 5G resource providers and customers. In this work we study telecommunication market and build services pricing scheme for the welfare maximization and for the companies profit maximization. We find the conditions under which investments in new technologies of 5G, Internet of Things (IoT) and big data increase welfare. We also study the effects of investments in new technologies on the optimal service price, the network capacity, the company net revenue and profit under conditions of monopoly and duopoly on the telecommunication market.
{"title":"Telecommunication market model and optimal pricing scheme of 5G services","authors":"Leonid A. Sevastianov, Sergey A. Vasilyev","doi":"10.1109/ICUMT.2018.8631269","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631269","url":null,"abstract":"Telecommunication and IT companies are looking forward to the implementation of 5G technology. The driving factors of this technology is aggregation of computing and networking resources. The 5G services will be more complicated than usual online services not only in technological methods, but also from an economic problems: fast service development, productive utilization of networks resources, dynamic adjustment to real market demand are all direct benefits of the integration 5G infrastructure. In this paper we study the economic mutual influence between 5G resource providers and customers. In this work we study telecommunication market and build services pricing scheme for the welfare maximization and for the companies profit maximization. We find the conditions under which investments in new technologies of 5G, Internet of Things (IoT) and big data increase welfare. We also study the effects of investments in new technologies on the optimal service price, the network capacity, the company net revenue and profit under conditions of monopoly and duopoly on the telecommunication market.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124922838","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631262
Pavel Rvbin, A. Frolov
In this paper we consider low-density parity-check (LDPC) codes with special construction. We obtain the lower-bounds on the error exponents for these codes under proposed low-complexity decoding algorithm and under a well known maximum likelihood decoding algorithm. We show that such LDPC code with special construction exists, that the error probability of the low-complexity decoding algorithm exponentially decreases with the code length for all code rates below the channel capacity. We also show that obtained lower-bound on the error exponent under the maximum likelihood decoding almost reaches the lower-bound on the error exponent of good linear codes under the maximum likelihood decoding. The error exponents are computed numerically for different code parameters.
{"title":"On the Error Exponents of Capacity Approaching Construction of LDPC code","authors":"Pavel Rvbin, A. Frolov","doi":"10.1109/ICUMT.2018.8631262","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631262","url":null,"abstract":"In this paper we consider low-density parity-check (LDPC) codes with special construction. We obtain the lower-bounds on the error exponents for these codes under proposed low-complexity decoding algorithm and under a well known maximum likelihood decoding algorithm. We show that such LDPC code with special construction exists, that the error probability of the low-complexity decoding algorithm exponentially decreases with the code length for all code rates below the channel capacity. We also show that obtained lower-bound on the error exponent under the maximum likelihood decoding almost reaches the lower-bound on the error exponent of good linear codes under the maximum likelihood decoding. The error exponents are computed numerically for different code parameters.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130439319","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631239
Joao Madeira, João Guerreiro, R. Dinis
The transmitted signals in multi-input, multi-output (MIMO) systems employing singular value decomposition (SVD) techniques can have large envelope fluctuations, even when single-carrier modulations are employed, which leads to amplification difficulties and makes them prone to nonlinear distortion effects. In this paper we consider the use of MIMO-SVD techniques with single-carrier with frequency-domain equalization (SC-FDE) modulations, together with strongly nonlinear amplifiers. The singular modes are interleaved among the antennas, which allows improved performance. To achieve this potential performance, we propose an iterative frequency-domain receiver that combines equalization with cancellation of nonlinear distortion effects. Our performance results show that the proposed receivers can have excellent performance with just a few iterations, making this technique particularly interesting for point-to-point communications with multiple antennas at the transmitter and the receiver.
{"title":"Iterative Frequency-Domain Detection for MIMO Systems with Strong Nonlinear Distortion Effects","authors":"Joao Madeira, João Guerreiro, R. Dinis","doi":"10.1109/ICUMT.2018.8631239","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631239","url":null,"abstract":"The transmitted signals in multi-input, multi-output (MIMO) systems employing singular value decomposition (SVD) techniques can have large envelope fluctuations, even when single-carrier modulations are employed, which leads to amplification difficulties and makes them prone to nonlinear distortion effects. In this paper we consider the use of MIMO-SVD techniques with single-carrier with frequency-domain equalization (SC-FDE) modulations, together with strongly nonlinear amplifiers. The singular modes are interleaved among the antennas, which allows improved performance. To achieve this potential performance, we propose an iterative frequency-domain receiver that combines equalization with cancellation of nonlinear distortion effects. Our performance results show that the proposed receivers can have excellent performance with just a few iterations, making this technique particularly interesting for point-to-point communications with multiple antennas at the transmitter and the receiver.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122979415","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631274
A. Muthanna, A. Volkov, A. Khakimov, S. Muhizi, R. Kirichek, A. Koucheryavy
For the time being, the traffic generated by smart devices becomes a significant part of Internet. Moreover, smart devices require mobility and guaranteed quality of services which need to be managed somehow. Potentially, SDN-based technologies (5G) will be used in Internet community for managing all types of services and therefore, SDN is to be tasked to manage these kinds of demands as well. In general., a significant number of the available Internet services and applications require exact value of network parameters such as latency, jitter, RTT and bandwidth. The SDN-based technologies should be able to control and manage dynamic QoS for different IoT -based applications. As a result, using SDN for controlling network parameters, will give a possibility to implement new services such as tactile Internet, augmented reality, e-health applications, to name a few. In this regards, there is a need to develop a protocol which aim is to inform SDN network controller about network performance parameters requested by IoT based end-device. The protocol is responsible for controlling QoS parameters through establishing connection with SDN controller over Openflow protocol (version 1.3 or higher).
{"title":"Framework of QoS Management for Time Constraint Services with Requested Network Parameters based on SDN/NFV Infrastructure","authors":"A. Muthanna, A. Volkov, A. Khakimov, S. Muhizi, R. Kirichek, A. Koucheryavy","doi":"10.1109/ICUMT.2018.8631274","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631274","url":null,"abstract":"For the time being, the traffic generated by smart devices becomes a significant part of Internet. Moreover, smart devices require mobility and guaranteed quality of services which need to be managed somehow. Potentially, SDN-based technologies (5G) will be used in Internet community for managing all types of services and therefore, SDN is to be tasked to manage these kinds of demands as well. In general., a significant number of the available Internet services and applications require exact value of network parameters such as latency, jitter, RTT and bandwidth. The SDN-based technologies should be able to control and manage dynamic QoS for different IoT -based applications. As a result, using SDN for controlling network parameters, will give a possibility to implement new services such as tactile Internet, augmented reality, e-health applications, to name a few. In this regards, there is a need to develop a protocol which aim is to inform SDN network controller about network performance parameters requested by IoT based end-device. The protocol is responsible for controlling QoS parameters through establishing connection with SDN controller over Openflow protocol (version 1.3 or higher).","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115246166","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631276
Krystof Zeman, Martin Stusek, Pavel Mašek, Jiri Hosek, Jindriska Sedova
Millimeter wave (mmWave) communication has raised increasing attentions from both academia and industry due to its exceptional advantages. As a part of the 5G New Radio mobile systems, mmWave communications adopt much higher carrier frequencies and thus come with advantages including huge bandwidth, narrow beam, and high transmission quality. No doubt, there are disadvantages e.g., severe signal attenuation, easily blocked by obstacles, and small coverage, due to its short wavelengths. Hence, the major challenge is to overcome its shortcomings while fully utilizing its advantages. In this paper, we present the new enhanced model which is based on a ray tracing algorithm. The main advantage of presented model over the old one is 3D path-loss calculation, reduced algorithm and computational complexity. The results from two simulation scenarios are discussed to provide better understanding of the importance of the blockage objects thickness. To further increase the understandability, we present the scenarios' blockage objects as buildings.
{"title":"Enhanced 3D Propagation Loss Model for mmWave Communications","authors":"Krystof Zeman, Martin Stusek, Pavel Mašek, Jiri Hosek, Jindriska Sedova","doi":"10.1109/ICUMT.2018.8631276","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631276","url":null,"abstract":"Millimeter wave (mmWave) communication has raised increasing attentions from both academia and industry due to its exceptional advantages. As a part of the 5G New Radio mobile systems, mmWave communications adopt much higher carrier frequencies and thus come with advantages including huge bandwidth, narrow beam, and high transmission quality. No doubt, there are disadvantages e.g., severe signal attenuation, easily blocked by obstacles, and small coverage, due to its short wavelengths. Hence, the major challenge is to overcome its shortcomings while fully utilizing its advantages. In this paper, we present the new enhanced model which is based on a ray tracing algorithm. The main advantage of presented model over the old one is 3D path-loss calculation, reduced algorithm and computational complexity. The results from two simulation scenarios are discussed to provide better understanding of the importance of the blockage objects thickness. To further increase the understandability, we present the scenarios' blockage objects as buildings.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115652945","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631201
Abdelhamied A. Ateya, A. Muthanna, M. Makolkina, A. Koucheryavy
5G cellular system is expected to meet the market segments requirements, by introducing new use case and services beside the traditional services introduced by the current cellular systems. Various types of services and applications are expected to be delivered by the 5G systems with different requirements and deployment scenarios. The 3GPP defines these services and their market impacts in release 14 and 15. In this work, we review all 5G uses cases announced by the 3GPP release 14 and 15 for the 5G systems. The main categories of these use case are defined including their specifications and requirements. Furthermore, some main use cases are introduced including their deployment scenarios and potential services requirements. We conduct all features and requirements of these services from the 3GPP release 14 and 15.
{"title":"Study of 5G Services Standardization: Specifications and Requirements","authors":"Abdelhamied A. Ateya, A. Muthanna, M. Makolkina, A. Koucheryavy","doi":"10.1109/ICUMT.2018.8631201","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631201","url":null,"abstract":"5G cellular system is expected to meet the market segments requirements, by introducing new use case and services beside the traditional services introduced by the current cellular systems. Various types of services and applications are expected to be delivered by the 5G systems with different requirements and deployment scenarios. The 3GPP defines these services and their market impacts in release 14 and 15. In this work, we review all 5G uses cases announced by the 3GPP release 14 and 15 for the 5G systems. The main categories of these use case are defined including their specifications and requirements. Furthermore, some main use cases are introduced including their deployment scenarios and potential services requirements. We conduct all features and requirements of these services from the 3GPP release 14 and 15.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132522787","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631202
L. D. Dilie, E. Y. Emelyanova, V. Petrov, E. Popova, A. A. Khokhlov
Authors used factor analysis (Singular Spectrum Analysis method) applied for data collected from mobile device accelerometer fixed on human body while human walking, running and making other moves.
{"title":"Analysis of data from accelerometers of mobile devices","authors":"L. D. Dilie, E. Y. Emelyanova, V. Petrov, E. Popova, A. A. Khokhlov","doi":"10.1109/ICUMT.2018.8631202","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631202","url":null,"abstract":"Authors used factor analysis (Singular Spectrum Analysis method) applied for data collected from mobile device accelerometer fixed on human body while human walking, running and making other moves.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125351777","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}
Pub Date : 2018-11-01DOI: 10.1109/ICUMT.2018.8631227
J. Koton, Jørgen Hagset Stavnesli, T. Freeborn
The description and definition of various systems using fractional-order calculus continues to gain attention in a variety of field of engineering. This is especially true for the design of analogue function blocks, where the factional-order Laplace operator $s^{alpha}$, whereas $0 < alpha < 1$, is frequently used to design the fractional to design the transfer functions of these blocks. In this paper we focus on analysing the Oustaloup approximation of $s^{alpha}$ to provide a tool that can support selecting the appropriate approximation to obtain a response that satisfies the designers' requirements of approximation error in magnitude and/or phase in a specific frequency range for the minimal possible order $N$ of the approximation.
{"title":"Performance Analysis of Oustaloup Approximation for the Design of Fractional-Order Analogue Circuits","authors":"J. Koton, Jørgen Hagset Stavnesli, T. Freeborn","doi":"10.1109/ICUMT.2018.8631227","DOIUrl":"https://doi.org/10.1109/ICUMT.2018.8631227","url":null,"abstract":"The description and definition of various systems using fractional-order calculus continues to gain attention in a variety of field of engineering. This is especially true for the design of analogue function blocks, where the factional-order Laplace operator $s^{alpha}$, whereas $0 < alpha < 1$, is frequently used to design the fractional to design the transfer functions of these blocks. In this paper we focus on analysing the Oustaloup approximation of $s^{alpha}$ to provide a tool that can support selecting the appropriate approximation to obtain a response that satisfies the designers' requirements of approximation error in magnitude and/or phase in a specific frequency range for the minimal possible order $N$ of the approximation.","PeriodicalId":211042,"journal":{"name":"2018 10th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123145768","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}
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