The ever-increasing number of mobile devices connected to cellular networks is heavily modifying the traffic observed in these networks. The traffic volumes and patterns generated by smartphones pose novel challenges to cellular network operators. One of these challenges relates to the automatic detection and diagnosis of unforeseen network traffic anomalies caused by specific devices and apps. Synchronized apps generating flashcrowds, device-specific traffic misbehaviors impacting network performance and end-users Quality of Experience (QoE), and other similar anomalies need to be rapidly detected and diagnosed. In this paper we characterize a new type of anomalies impacting cellular networks, caused by the multiple, constantly-connected apps running in smartphones and other end-user devices. We additionally devise a novel detection and classification technique based on semi-supervised Machine Learning (ML) algorithms to automatically detect and diagnose anomalies of this class with minimal training, and compare its performance to that achieved by other well-known supervised learning classifiers. The proposed solution is evaluated using synthetically generated data from an operational cellular ISP, drawn from real traffic statistics to resemble both the real cellular network traffic and the characterized type of anomalies.
{"title":"When smartphones become the enemy: unveiling mobile apps anomalies through clustering techniques","authors":"P. Casas, P. Fiadino, A. D'Alconzo","doi":"10.1145/2980055.2980058","DOIUrl":"https://doi.org/10.1145/2980055.2980058","url":null,"abstract":"The ever-increasing number of mobile devices connected to cellular networks is heavily modifying the traffic observed in these networks. The traffic volumes and patterns generated by smartphones pose novel challenges to cellular network operators. One of these challenges relates to the automatic detection and diagnosis of unforeseen network traffic anomalies caused by specific devices and apps. Synchronized apps generating flashcrowds, device-specific traffic misbehaviors impacting network performance and end-users Quality of Experience (QoE), and other similar anomalies need to be rapidly detected and diagnosed. In this paper we characterize a new type of anomalies impacting cellular networks, caused by the multiple, constantly-connected apps running in smartphones and other end-user devices. We additionally devise a novel detection and classification technique based on semi-supervised Machine Learning (ML) algorithms to automatically detect and diagnose anomalies of this class with minimal training, and compare its performance to that achieved by other well-known supervised learning classifiers. The proposed solution is evaluated using synthetically generated data from an operational cellular ISP, drawn from real traffic statistics to resemble both the real cellular network traffic and the characterized type of anomalies.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133526192","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}
As an important component of the virtual reality (VR) technology, 360-degree videos provide users with panoramic view and allow them to freely control their viewing direction during video playback. Usually, a player displays only the visible portion of a 360 video. Thus, fetching the entire raw video frame wastes bandwidth. In this paper, we consider the problem of optimizing 360 video delivery over cellular networks. We first conduct a measurement study on commercial 360 video platforms. We then propose a cellular-friendly streaming scheme that delivers only 360 videos' visible portion based on head movement prediction. Using viewing data collected from real users, we demonstrate the feasibility of our approach, which can reduce bandwidth consumption by up to 80% based on a trace-driven simulation.
{"title":"Optimizing 360 video delivery over cellular networks","authors":"Feng Qian, Lusheng Ji, B. Han, V. Gopalakrishnan","doi":"10.1145/2980055.2980056","DOIUrl":"https://doi.org/10.1145/2980055.2980056","url":null,"abstract":"As an important component of the virtual reality (VR) technology, 360-degree videos provide users with panoramic view and allow them to freely control their viewing direction during video playback. Usually, a player displays only the visible portion of a 360 video. Thus, fetching the entire raw video frame wastes bandwidth. In this paper, we consider the problem of optimizing 360 video delivery over cellular networks. We first conduct a measurement study on commercial 360 video platforms. We then propose a cellular-friendly streaming scheme that delivers only 360 videos' visible portion based on head movement prediction. Using viewing data collected from real users, we demonstrate the feasibility of our approach, which can reduce bandwidth consumption by up to 80% based on a trace-driven simulation.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127029464","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}
The centralised architecture of LTE networks will become a major problem with the forecasted growth of mobile traffic and users. The use of tunnelling all the way from a base station to a core network gives very little flexibility in routing and traffic management, and limits the possibility to offload central components. In this work, we propose MULTEX -- an opportunistic step towards a packet switched model for current and future generation mobile networks. MULTEX transforms a user terminal into a multi-homed device that is simultaneously and independently connected to several packet data networks with different geographical or logical boundaries.
{"title":"MULTEX: multiple PDN connections in LTE and beyond for enhanced routing and services","authors":"Dziugas Baltrunas, A. Elmokashfi, A. Kvalbein","doi":"10.1145/2980055.2980061","DOIUrl":"https://doi.org/10.1145/2980055.2980061","url":null,"abstract":"The centralised architecture of LTE networks will become a major problem with the forecasted growth of mobile traffic and users. The use of tunnelling all the way from a base station to a core network gives very little flexibility in routing and traffic management, and limits the possibility to offload central components. In this work, we propose MULTEX -- an opportunistic step towards a packet switched model for current and future generation mobile networks. MULTEX transforms a user terminal into a multi-homed device that is simultaneously and independently connected to several packet data networks with different geographical or logical boundaries.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"214 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116491467","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}
In this paper, we investigate when to browse the web using WiFi and cellular simultaneously on mobile devices. Our observation, based on empirical measurements, is that mobile web may not always benefit from multipath, which motivates a cost-benefit analysis. However, it is challenging to analyze the benefits (i.e., improved user experience) and costs (e.g., energy consumption) of web browsing, due to HTTP's resource fetching model. We propose to use server push, a standard feature in HTTP/2, to provide an ideal framework for the cost-benefit analysis. We then design a practical system that reduces resource footprint for mobile web over multipath by providing adaptive multipath support.
{"title":"When should we surf the mobile web using both wifi and cellular?","authors":"B. Han, Feng Qian, Lusheng Ji","doi":"10.1145/2980055.2980060","DOIUrl":"https://doi.org/10.1145/2980055.2980060","url":null,"abstract":"In this paper, we investigate when to browse the web using WiFi and cellular simultaneously on mobile devices. Our observation, based on empirical measurements, is that mobile web may not always benefit from multipath, which motivates a cost-benefit analysis. However, it is challenging to analyze the benefits (i.e., improved user experience) and costs (e.g., energy consumption) of web browsing, due to HTTP's resource fetching model. We propose to use server push, a standard feature in HTTP/2, to provide an ideal framework for the cost-benefit analysis. We then design a practical system that reduces resource footprint for mobile web over multipath by providing adaptive multipath support.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129922927","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}
Vasudevan Nagendra, H. Sharma, Ayon Chakraborty, Samir R Das
M2M (machine-to-machine) communications are bringing new challenges in the cellular networks as billions of such devices will need to be supported but at a fraction of the cost of today's smartphones. Analysis shows that while many of these devices generate little data load on the network, their control signaling load and memory/CPU resource consumption due to tunnel maintenance in the cellular core could still be significant. To address this scalability issue, we propose a modified packet core architecture for LTE networks called LTE-Xtend that customizes control message handling and tunnel management for M2M traffic. Evaluations using OpenAirInterface demonstrates significant scalability benefits in using LTE-Xtend.
{"title":"LTE-Xtend: scalable support of M2M devices in cellular packet core","authors":"Vasudevan Nagendra, H. Sharma, Ayon Chakraborty, Samir R Das","doi":"10.1145/2980055.2980062","DOIUrl":"https://doi.org/10.1145/2980055.2980062","url":null,"abstract":"M2M (machine-to-machine) communications are bringing new challenges in the cellular networks as billions of such devices will need to be supported but at a fraction of the cost of today's smartphones. Analysis shows that while many of these devices generate little data load on the network, their control signaling load and memory/CPU resource consumption due to tunnel maintenance in the cellular core could still be significant. To address this scalability issue, we propose a modified packet core architecture for LTE networks called LTE-Xtend that customizes control message handling and tunnel management for M2M traffic. Evaluations using OpenAirInterface demonstrates significant scalability benefits in using LTE-Xtend.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":" 16","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132188573","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}
Machine-to-Machine (M2M) communication devices are expected to work without recharging for several years. To receive a network-initiated transmission and to lower energy consumption, an M2M modem waits in the idle state and is woken up, when needed. The state-of-the-art M2M wake-up implementation over cellular networks is Short Message Service (SMS). SMS is a Circuit Switched service, which is not present in its original form in Packet Switched LTE. Therefore, we propose an Over-the-Top Session Initiation Protocol (OTT SIP) wake-up method. In this paper, we have implemented OTT SIP as well as SMS over GSM and LTE wake-up methods on a real testbed, connected to a mobile network. We have measured delay and energy consumption. Our measurement results are presented and analyzed in this paper. We also show that OTT SIP wake-up features three times lower delay than SMS over LTE.1
机器对机器(M2M)通信设备有望在无需充电的情况下工作数年。为了接收网络发起的传输并降低能耗，M2M调制解调器在空闲状态等待，并在需要时被唤醒。在蜂窝网络上最先进的M2M唤醒实现是短消息服务(SMS)。SMS是一种电路交换业务，在分组交换LTE中不以其原始形式存在。因此，我们提出一种OTT SIP (over - top Session Initiation Protocol)唤醒方法。在本文中，我们在连接到移动网络的真实测试台上实现了OTT SIP以及GSM和LTE上的短信唤醒方法。我们测量了延迟和能耗。本文给出了我们的测量结果并进行了分析。我们还表明，OTT SIP唤醒的延迟比通过LTE.1的短信低三倍
{"title":"M2M wake-ups over cellular networks: over-the-top SIP","authors":"E. Grigoreva, Jianghua Xu, W. Kellerer","doi":"10.1145/2980055.2980059","DOIUrl":"https://doi.org/10.1145/2980055.2980059","url":null,"abstract":"Machine-to-Machine (M2M) communication devices are expected to work without recharging for several years. To receive a network-initiated transmission and to lower energy consumption, an M2M modem waits in the idle state and is woken up, when needed. The state-of-the-art M2M wake-up implementation over cellular networks is Short Message Service (SMS). SMS is a Circuit Switched service, which is not present in its original form in Packet Switched LTE. Therefore, we propose an Over-the-Top Session Initiation Protocol (OTT SIP) wake-up method. In this paper, we have implemented OTT SIP as well as SMS over GSM and LTE wake-up methods on a real testbed, connected to a mobile network. We have measured delay and energy consumption. Our measurement results are presented and analyzed in this paper. We also show that OTT SIP wake-up features three times lower delay than SMS over LTE.1","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129558699","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}
George R. MacCartney, Shu Sun, T. Rappaport, Yunchou Xing, Hangsong Yan, Jeton Koka, Ruichen Wang, Dian Yu
This paper shows the remarkable distances that can be achieved using millimeter wave communications, and presents a new rural macrocell (RMa) path loss model for millimeter wave frequencies, based on measurements at 73 GHz in rural Virginia. Path loss models are needed to estimate signal coverage and interference for wireless network design, yet little is known about rural propagation at millimeter waves. This work identifies problems with the RMa model used by the 3rd Generation Partnership Project (3GPP) TR 38.900 Release 14, and offers a close-in (CI) reference distance model that has improved accuracy, fewer parameters, and better stability as compared with the existing 3GPP RMa path loss model. The measurements and models presented here are the first to validate rural millimeter wave path loss models.
{"title":"Millimeter wave wireless communications: new results for rural connectivity","authors":"George R. MacCartney, Shu Sun, T. Rappaport, Yunchou Xing, Hangsong Yan, Jeton Koka, Ruichen Wang, Dian Yu","doi":"10.1145/2980055.2987353","DOIUrl":"https://doi.org/10.1145/2980055.2987353","url":null,"abstract":"This paper shows the remarkable distances that can be achieved using millimeter wave communications, and presents a new rural macrocell (RMa) path loss model for millimeter wave frequencies, based on measurements at 73 GHz in rural Virginia. Path loss models are needed to estimate signal coverage and interference for wireless network design, yet little is known about rural propagation at millimeter waves. This work identifies problems with the RMa model used by the 3rd Generation Partnership Project (3GPP) TR 38.900 Release 14, and offers a close-in (CI) reference distance model that has improved accuracy, fewer parameters, and better stability as compared with the existing 3GPP RMa path loss model. The measurements and models presented here are the first to validate rural millimeter wave path loss models.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134107704","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}
Reliable network measurements are a fundamental component of networking research as they enable network analysis, system debugging, performance evaluation and optimization. In particular, decoding the LTE control channel would give access to the full base station traffic at a 1 ms granularity, thus allowing for traffic profiling and accurate measurements. Although a few open-source implementations of LTE are available, they do not provide tools to reliably decoding the LTE control channel and, thus, accessing the scheduling information. In this paper, we present OWL, an Online Watcher for LTE that is able to decode all the resource blocks in more than 99% of the system frames, significantly outperforming existing non-commercial prior decoders. Compared to previous attempts, OWL grounds the decoding procedure on information obtained from the LTE random access mechanism. This makes it possible to run our software on inexpensive hardware coupled with almost any software defined radio capable of sampling the LTE signal with sufficient accuracy.
{"title":"OWL: a reliable online watcher for LTE control channel measurements","authors":"N. Bui, J. Widmer","doi":"10.1145/2980055.2980057","DOIUrl":"https://doi.org/10.1145/2980055.2980057","url":null,"abstract":"Reliable network measurements are a fundamental component of networking research as they enable network analysis, system debugging, performance evaluation and optimization. In particular, decoding the LTE control channel would give access to the full base station traffic at a 1 ms granularity, thus allowing for traffic profiling and accurate measurements. Although a few open-source implementations of LTE are available, they do not provide tools to reliably decoding the LTE control channel and, thus, accessing the scheduling information. In this paper, we present OWL, an Online Watcher for LTE that is able to decode all the resource blocks in more than 99% of the system frames, significantly outperforming existing non-commercial prior decoders. Compared to previous attempts, OWL grounds the decoding procedure on information obtained from the LTE random access mechanism. This makes it possible to run our software on inexpensive hardware coupled with almost any software defined radio capable of sampling the LTE signal with sufficient accuracy.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125075891","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}
In the Networked Society anything that benefit from being connected, will be connected. Cellular technologies will be the backbone of creating connectivity for a large amount of connected devices of varying capabilities where the applications that these devices support have varying requirements ranging from ultra low cost and long battery time to high bandwidth, low delay, and ultra high reliability. This wide variety of requirements pose some new interesting challenges to the cellular networks. Creating a network architecture that can comprise extreme performance, flexible functionality and a drastically improved agility which makes sense for the future connected industries, is a challenge orders of magnitude greater than what we have seen before in previous generations of mobile networks. This talk will address these challenges that are associated with 5G from a core network and network architecture perspective and present a way forward to make the 5G vision a reality.
{"title":"Core Network Challenges in the 5G Time Frame","authors":"Goran Rune","doi":"10.1145/2785971.2785982","DOIUrl":"https://doi.org/10.1145/2785971.2785982","url":null,"abstract":"In the Networked Society anything that benefit from being connected, will be connected. Cellular technologies will be the backbone of creating connectivity for a large amount of connected devices of varying capabilities where the applications that these devices support have varying requirements ranging from ultra low cost and long battery time to high bandwidth, low delay, and ultra high reliability. This wide variety of requirements pose some new interesting challenges to the cellular networks. Creating a network architecture that can comprise extreme performance, flexible functionality and a drastically improved agility which makes sense for the future connected industries, is a challenge orders of magnitude greater than what we have seen before in previous generations of mobile networks. This talk will address these challenges that are associated with 5G from a core network and network architecture perspective and present a way forward to make the 5G vision a reality.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121482033","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}
In this study we examine the conditions in a current cellular network by examining data passively collected in the core of a cellular operator during a 24-hour period. More than 2 billion traffic measurement data points from over 500,000 cellular users are analyzed. The analysis characterizes the Time-of-Day (ToD) variations for traffic intensity and session length and serves as a complement to the active measurements also performed. A comprehensive active measurement campaign was completed in the HSDPA+ and LTE networks of the four major Swedish operators. We collect around 50,000 data points from stationary cellular modems and analyze the ToD variation pattern for underlying network layer metrics such as delay and throughput. In conjunction with the time-varying session size distribution obtained from the passive measurements, we then analyze the ToD impact on TCP flows of varying sizes. The ToD effects are examined using time series analysis with Lomb-Scargle periodograms and differential Bayesian Information Criterion to allow comparison of the relative impact of the network ToD effects. The results show that ToD effects are predominantly impacting longer-running flows, and although short flows are also impacted they are mostly constrained by other issues such as protocol efficiency.
{"title":"Examining TCP Short Flow Performance in Cellular Networks Through Active and Passive Measurements","authors":"Johan Garcia, Stefan Alfredsson, A. Brunström","doi":"10.1145/2785971.2785974","DOIUrl":"https://doi.org/10.1145/2785971.2785974","url":null,"abstract":"In this study we examine the conditions in a current cellular network by examining data passively collected in the core of a cellular operator during a 24-hour period. More than 2 billion traffic measurement data points from over 500,000 cellular users are analyzed. The analysis characterizes the Time-of-Day (ToD) variations for traffic intensity and session length and serves as a complement to the active measurements also performed. A comprehensive active measurement campaign was completed in the HSDPA+ and LTE networks of the four major Swedish operators. We collect around 50,000 data points from stationary cellular modems and analyze the ToD variation pattern for underlying network layer metrics such as delay and throughput. In conjunction with the time-varying session size distribution obtained from the passive measurements, we then analyze the ToD impact on TCP flows of varying sizes. The ToD effects are examined using time series analysis with Lomb-Scargle periodograms and differential Bayesian Information Criterion to allow comparison of the relative impact of the network ToD effects. The results show that ToD effects are predominantly impacting longer-running flows, and although short flows are also impacted they are mostly constrained by other issues such as protocol efficiency.","PeriodicalId":166050,"journal":{"name":"Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123330279","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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