Network simulations are often the first choice to design, test, and evaluate novel applications and protocols for vehicular networks. Aiming for higher realism, simulators become increasingly complex, relying on detailed simulation models that are developed by different communities. With this trend, it also becomes difficult to understand all models in detail and researchers might lack the expert knowledge to parameterize such models properly. In this paper, we identify suboptimal default parameter values for physical layer effects in common simulation frameworks and show how they can negatively impact the results. We also review papers that use said simulation models and highlight that this is not simply a theoretical issue: We found that the majority of the papers simply copy these default parameter values or do not mention physical layer parameters at all. Both cases are clearly problematic. We thus argue that we should focus on reasonable default parameter values just as much as on the functional correctness of simulation models.
{"title":"A Case for Good Defaults: Pitfalls in VANET Physical Layer Simulations","authors":"Bastian Bloessl, Aisling O'Driscoll","doi":"10.1109/WD.2019.8734227","DOIUrl":"https://doi.org/10.1109/WD.2019.8734227","url":null,"abstract":"Network simulations are often the first choice to design, test, and evaluate novel applications and protocols for vehicular networks. Aiming for higher realism, simulators become increasingly complex, relying on detailed simulation models that are developed by different communities. With this trend, it also becomes difficult to understand all models in detail and researchers might lack the expert knowledge to parameterize such models properly. In this paper, we identify suboptimal default parameter values for physical layer effects in common simulation frameworks and show how they can negatively impact the results. We also review papers that use said simulation models and highlight that this is not simply a theoretical issue: We found that the majority of the papers simply copy these default parameter values or do not mention physical layer parameters at all. Both cases are clearly problematic. We thus argue that we should focus on reasonable default parameter values just as much as on the functional correctness of simulation models.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131851796","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}
Mohammad Irfan Khan, François-Xavier Aubet, Marc-Oliver Pahl, Jérôme Härri
IEEE 802.11p based V2X communication uses stochastic medium access control, which cannot prevent broadcast packet collision, in particular during high channel load. Wireless congestion control has been designed to keep the channel load at an optimal point. However, vehicles’ lack of precise and granular knowledge about true channel activity, in time and space, makes it impossible to fully avoid packet collisions. In this paper, we propose a machine learning approach using deep neural network for learning vehicles’ transmit patterns, and as such predicting future channel activity in space and time. We evaluate the performance of our proposal via simulation considering multiple safety-related V2X services involving heterogeneous transmit patterns. Our results show that predicting channel activity, and transmitting accordingly, reduces collisions and significantly improves communication performance.
{"title":"Deep Learning-aided Resource Orchestration for Vehicular Safety Communication","authors":"Mohammad Irfan Khan, François-Xavier Aubet, Marc-Oliver Pahl, Jérôme Härri","doi":"10.1109/WD.2019.8734252","DOIUrl":"https://doi.org/10.1109/WD.2019.8734252","url":null,"abstract":"IEEE 802.11p based V2X communication uses stochastic medium access control, which cannot prevent broadcast packet collision, in particular during high channel load. Wireless congestion control has been designed to keep the channel load at an optimal point. However, vehicles’ lack of precise and granular knowledge about true channel activity, in time and space, makes it impossible to fully avoid packet collisions. In this paper, we propose a machine learning approach using deep neural network for learning vehicles’ transmit patterns, and as such predicting future channel activity in space and time. We evaluate the performance of our proposal via simulation considering multiple safety-related V2X services involving heterogeneous transmit patterns. Our results show that predicting channel activity, and transmitting accordingly, reduces collisions and significantly improves communication performance.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125736813","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}
Aashik Chandramohan, M. Poel, B. Meijerink, G. Heijenk
Most of the research in automated driving currently involves using the on-board sensors on the vehicle to collect information regarding surrounding vehicles to maneuver around them. In this paper we discuss how information communicated through vehicular networking can be used for controlling an autonomous vehicle in a multi-lane highway environment. A driving algorithm is designed using deep Q learning, a type of reinforcement learning. In order to train and test driving algorithms, we deploy a simulated traffic system, using SUMO (Simulation of Urban Mobility). The performance of the driving algorithm is tested for perfect knowledge regarding surrounding vehicles. Furthermore, the impact of limited communication range and random packet loss is investigated. Currently the performance of the driving algorithm is far from ideal with the collision ratios being quite high. We propose directions for additional research to improve the performance of the algorithm.
{"title":"Machine Learning for Cooperative Driving in a Multi-Lane Highway Environment","authors":"Aashik Chandramohan, M. Poel, B. Meijerink, G. Heijenk","doi":"10.1109/WD.2019.8734192","DOIUrl":"https://doi.org/10.1109/WD.2019.8734192","url":null,"abstract":"Most of the research in automated driving currently involves using the on-board sensors on the vehicle to collect information regarding surrounding vehicles to maneuver around them. In this paper we discuss how information communicated through vehicular networking can be used for controlling an autonomous vehicle in a multi-lane highway environment. A driving algorithm is designed using deep Q learning, a type of reinforcement learning. In order to train and test driving algorithms, we deploy a simulated traffic system, using SUMO (Simulation of Urban Mobility). The performance of the driving algorithm is tested for perfect knowledge regarding surrounding vehicles. Furthermore, the impact of limited communication range and random packet loss is investigated. Currently the performance of the driving algorithm is far from ideal with the collision ratios being quite high. We propose directions for additional research to improve the performance of the algorithm.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124902805","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 recent years, in a hospital, a biological information monitoring system that constantly monitors biological information such as blood pressure and heart rate to grasp a patient's condition is generally used. However, in the current system, 420 to 450 MHz band are mainly used, and it is difficult to manage such as channel switching and device addition/deletion to wireless communication experts. Also, there is a problem that a transmitter having a size as large as a small terminal must be carried around. Therefore, we proposed the textile antenna using the 5.2 GHz band as a transmitting antenna of the system. In this paper, we report on the antenna characteristics when a transmitting antenna designed by the authors is placed on the human body and the result of received power transmitted by the textile antenna analysis in an imitated actual environment model.
{"title":"Investigation of the Characteristics of a 5.2 GHz Textile Antenna on a Human Body","authors":"D. Yamanaka, Masaharu Takahashi","doi":"10.1109/WD.2019.8734212","DOIUrl":"https://doi.org/10.1109/WD.2019.8734212","url":null,"abstract":"In recent years, in a hospital, a biological information monitoring system that constantly monitors biological information such as blood pressure and heart rate to grasp a patient's condition is generally used. However, in the current system, 420 to 450 MHz band are mainly used, and it is difficult to manage such as channel switching and device addition/deletion to wireless communication experts. Also, there is a problem that a transmitter having a size as large as a small terminal must be carried around. Therefore, we proposed the textile antenna using the 5.2 GHz band as a transmitting antenna of the system. In this paper, we report on the antenna characteristics when a transmitting antenna designed by the authors is placed on the human body and the result of received power transmitted by the textile antenna analysis in an imitated actual environment model.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131942958","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}
K. Okello, A. El-Malek, M. Elsabrouty, M. Abo-Zahhad
Spectrum sensing is an essential operation in cognitive radio networks. In this paper, we consider a dynamic spectrum sensing system consisting of both non-cooperative mobile cognitive radio(CR) secondary users and mobile non-cognitive radio primary users. Key performance metrics such as detection capability and sensing capacity are evaluated. Two mobility models are adopted for both secondary and primary users. The relative distance distribution associating the independent mobile users is analyzed and given in both 1- and 2-dimensions. Expressions for both performance metrics are derived, and simulations are performed to validate the theoretical analyses.
{"title":"Spectrum Sensing Performance Analysis for Mobile Primary and Secondary Users in Cognitive Radio Networks","authors":"K. Okello, A. El-Malek, M. Elsabrouty, M. Abo-Zahhad","doi":"10.1109/WD.2019.8734191","DOIUrl":"https://doi.org/10.1109/WD.2019.8734191","url":null,"abstract":"Spectrum sensing is an essential operation in cognitive radio networks. In this paper, we consider a dynamic spectrum sensing system consisting of both non-cooperative mobile cognitive radio(CR) secondary users and mobile non-cognitive radio primary users. Key performance metrics such as detection capability and sensing capacity are evaluated. Two mobility models are adopted for both secondary and primary users. The relative distance distribution associating the independent mobile users is analyzed and given in both 1- and 2-dimensions. Expressions for both performance metrics are derived, and simulations are performed to validate the theoretical analyses.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114988569","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}
Understanding delay performance is essential for successful development and deployment of real-time networked sensing applications. In this work, we characterize the end-to-end delay on a multi-hop Wireless Sensor Network (WSN) with an analytical method based on Stochastic Network Calculus (SNC) with Moment Generating Functions (MGF). The particularity of the sensing scenario is that all nodes generate and cooperatively forward their traffic through the network to a main location, known as the sink. We tackled the problem by modeling the service process of fading wireless channels from a high-layer perspective with Finite-State Markov Chains (FSMC). Numerical performance bounds are provided for an example WSN with IEEE 802.11g ad-hoc links in which the effects of delay bound violation probability, per-node offered load, data rate and fading speed are quantified for different network sizes. Finally, the presented analysis is validated through a comparison between analytical and numerical simulation results.
{"title":"End-to-End Delay Analysis of a Wireless Sensor Network Using Stochastic Network Calculus","authors":"Orangel Azuaje, Ana Aguiar","doi":"10.1109/WD.2019.8734241","DOIUrl":"https://doi.org/10.1109/WD.2019.8734241","url":null,"abstract":"Understanding delay performance is essential for successful development and deployment of real-time networked sensing applications. In this work, we characterize the end-to-end delay on a multi-hop Wireless Sensor Network (WSN) with an analytical method based on Stochastic Network Calculus (SNC) with Moment Generating Functions (MGF). The particularity of the sensing scenario is that all nodes generate and cooperatively forward their traffic through the network to a main location, known as the sink. We tackled the problem by modeling the service process of fading wireless channels from a high-layer perspective with Finite-State Markov Chains (FSMC). Numerical performance bounds are provided for an example WSN with IEEE 802.11g ad-hoc links in which the effects of delay bound violation probability, per-node offered load, data rate and fading speed are quantified for different network sizes. Finally, the presented analysis is validated through a comparison between analytical and numerical simulation results.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123133294","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}
Nardine Basta, A. El-Nahas, H. P. Großmann, Slim Abdennadher
The tie strength is a network concept that has attracted arguably the most research attention as being an important ingredient for modeling the interaction of users in a network and understanding their behavior. With the emergence of online social networks like Facebook and Twitter, the social tie strength interpretation evolved to reflect the frequency of contact on computer-mediated communication networks. The rapid proliferation of Mobile Adhoc Networks and in particular vehicular networks creates ample opportunity for novel applications relying on the human mobility characteristics such as vehicles destination prediction and recommendation systems. Hence, arises the need for a novel definition of the social tie strength reflecting the meetings frequency of the network nodes. This paper sets the ground work for quantifying the social tie strength in vehicular social networks. It presents a new definition for the social tie strength and formalizes a semantic aware model namely the Social, Spatial and Context-based Encounter Frequency (SSCEF) to quantify the strength as per the suggested definition. The model is tested using a data-set collected at the city of Ulm, Germany for the purpose of this study. It comprises social network information and its associated one month mobility traces. The performance of the proposed model is further validated by feeding the inferred ties to a social-based vehicular destination predictor [4]. The SSCEF inferred ties achieves a prediction accuracy of 67% in comparison to 70% for the original traces-based calculated ties.
{"title":"A Framework for Social Tie Strength Inference in Vehicular Social Networks","authors":"Nardine Basta, A. El-Nahas, H. P. Großmann, Slim Abdennadher","doi":"10.1109/WD.2019.8734218","DOIUrl":"https://doi.org/10.1109/WD.2019.8734218","url":null,"abstract":"The tie strength is a network concept that has attracted arguably the most research attention as being an important ingredient for modeling the interaction of users in a network and understanding their behavior. With the emergence of online social networks like Facebook and Twitter, the social tie strength interpretation evolved to reflect the frequency of contact on computer-mediated communication networks. The rapid proliferation of Mobile Adhoc Networks and in particular vehicular networks creates ample opportunity for novel applications relying on the human mobility characteristics such as vehicles destination prediction and recommendation systems. Hence, arises the need for a novel definition of the social tie strength reflecting the meetings frequency of the network nodes. This paper sets the ground work for quantifying the social tie strength in vehicular social networks. It presents a new definition for the social tie strength and formalizes a semantic aware model namely the Social, Spatial and Context-based Encounter Frequency (SSCEF) to quantify the strength as per the suggested definition. The model is tested using a data-set collected at the city of Ulm, Germany for the purpose of this study. It comprises social network information and its associated one month mobility traces. The performance of the proposed model is further validated by feeding the inferred ties to a social-based vehicular destination predictor [4]. The SSCEF inferred ties achieves a prediction accuracy of 67% in comparison to 70% for the original traces-based calculated ties.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133383268","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, a novel system-on-chip (SoC) based software defined radio (SDR) platform is presented. This platform addresses the challenges of software defined processing and rapid prototyping in the micro- and millimeter wave frequency region. After presenting the mentioned challenges and system requirements as well as an overview of the SDR platform, the interface between the processing system and the programmable logic is discussed in detail. Application references for ultra-high data rate 60 GHz communication systems, 120 GHz pseudo-noise MIMO radar as well as high resolution ranging and localization systems are given.
{"title":"A SoC-based SDR platform for ultra-high data rate broadband communication, radar and localization systems","authors":"Markus Petri, M. Ehrig","doi":"10.1109/WD.2019.8734240","DOIUrl":"https://doi.org/10.1109/WD.2019.8734240","url":null,"abstract":"In this paper, a novel system-on-chip (SoC) based software defined radio (SDR) platform is presented. This platform addresses the challenges of software defined processing and rapid prototyping in the micro- and millimeter wave frequency region. After presenting the mentioned challenges and system requirements as well as an overview of the SDR platform, the interface between the processing system and the programmable logic is discussed in detail. Application references for ultra-high data rate 60 GHz communication systems, 120 GHz pseudo-noise MIMO radar as well as high resolution ranging and localization systems are given.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124325899","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}
Networks are more and more composed of heterogeneous devices that are intermittently connected. Intermittences are induced by the mobility of devices communicating through short-range wireless interfaces, and by the sleep phases made by devices for energy saving purposes. Discovering, invoking and compositing services in such networks can therefore be difficult tasks. This paper presents a middleware system to achieve these tasks efficiently, thanks to opportunistic networking and computing techniques that are designed to minimize the execution time of these tasks, as well as to maximize their success ratio.
{"title":"Performing Service Composition in Opportunistic Networks","authors":"Fadhlallah Baklouti, N. L. Sommer, Y. Mahéo","doi":"10.1109/WD.2019.8734201","DOIUrl":"https://doi.org/10.1109/WD.2019.8734201","url":null,"abstract":"Networks are more and more composed of heterogeneous devices that are intermittently connected. Intermittences are induced by the mobility of devices communicating through short-range wireless interfaces, and by the sleep phases made by devices for energy saving purposes. Discovering, invoking and compositing services in such networks can therefore be difficult tasks. This paper presents a middleware system to achieve these tasks efficiently, thanks to opportunistic networking and computing techniques that are designed to minimize the execution time of these tasks, as well as to maximize their success ratio.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126101624","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}
Absar-Ul-Haque Ahmar, Emekcan Aras, W. Joosen, D. Hughes
The Internet of Things (IoT) vision has recently given rise to low-power wide area networks(LP-WAN) which offer multi-km communication range. Ericsson and Cisco Internet Business Solutions Group (IBSG) predict that by 2025, more than 50 billion devices will be connected through LPWAN technologies to collect real world data [1]. LoRaWAN is being deployed by many countries around the globe and gaining rapid acceptance and popularity in the LPWAN space. LoRa technology has enabled a new type of low data-rate services that are suitable for wide geographical areas with several years of battery life. However, the technology has limitations that need to be addressed. The high-density development of end devices transmitting using uncoordinated messaging makes the network more vulnerable to selective jamming and network contention. This paper proposes a solution to mitigate these effects through secure random frequency selection on end devices(i.e. cryptographic frequency hopping). In particular, proper time, spreading factor (SF) and frequency selection may allow multiple unconfirmed communications to occur concurrently while minimizing opportunities for contention and jamming. This was done by implementing cryptographic frequency hopping technique to select N-possible number of evenly optimized channels from available frequency spectrum (EU863-870MHz). The results were implemented and evaluated using commodity hardware.
{"title":"Towards More Scalable and Secure LPWAN Networks Using Cryptographic Frequency Hopping","authors":"Absar-Ul-Haque Ahmar, Emekcan Aras, W. Joosen, D. Hughes","doi":"10.1109/WD.2019.8734249","DOIUrl":"https://doi.org/10.1109/WD.2019.8734249","url":null,"abstract":"The Internet of Things (IoT) vision has recently given rise to low-power wide area networks(LP-WAN) which offer multi-km communication range. Ericsson and Cisco Internet Business Solutions Group (IBSG) predict that by 2025, more than 50 billion devices will be connected through LPWAN technologies to collect real world data [1]. LoRaWAN is being deployed by many countries around the globe and gaining rapid acceptance and popularity in the LPWAN space. LoRa technology has enabled a new type of low data-rate services that are suitable for wide geographical areas with several years of battery life. However, the technology has limitations that need to be addressed. The high-density development of end devices transmitting using uncoordinated messaging makes the network more vulnerable to selective jamming and network contention. This paper proposes a solution to mitigate these effects through secure random frequency selection on end devices(i.e. cryptographic frequency hopping). In particular, proper time, spreading factor (SF) and frequency selection may allow multiple unconfirmed communications to occur concurrently while minimizing opportunities for contention and jamming. This was done by implementing cryptographic frequency hopping technique to select N-possible number of evenly optimized channels from available frequency spectrum (EU863-870MHz). The results were implemented and evaluated using commodity hardware.","PeriodicalId":432101,"journal":{"name":"2019 Wireless Days (WD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131246203","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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