Pub Date : 2019-01-01DOI: 10.1109/CCNC.2019.8651811
Steffen Linsenmayer, Ben W. Carabelli, Frank Dürr, Jonathan Falk, F. Allgöwer, K. Rothermel
In this paper, we present a communication abstraction for Networked Control Systems that is characterized by a slotted transmission classification model. We discuss, how such a model can be implemented over local area networks by using IEEE Time Sensitive Networking methods. Furthermore, it is shown how asymptotic stability can be analyzed for linear systems that communicate over such a network. Based on the stability result, a controller design procedure is derived that takes the information captured in the network model into account. Further topics and related open problems that are implicated by the proposed model are briefly discussed as an outlook.
{"title":"Integration of Communication Networks and Control Systems Using a Slotted Transmission Classification Model","authors":"Steffen Linsenmayer, Ben W. Carabelli, Frank Dürr, Jonathan Falk, F. Allgöwer, K. Rothermel","doi":"10.1109/CCNC.2019.8651811","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651811","url":null,"abstract":"In this paper, we present a communication abstraction for Networked Control Systems that is characterized by a slotted transmission classification model. We discuss, how such a model can be implemented over local area networks by using IEEE Time Sensitive Networking methods. Furthermore, it is shown how asymptotic stability can be analyzed for linear systems that communicate over such a network. Based on the stability result, a controller design procedure is derived that takes the information captured in the network model into account. Further topics and related open problems that are implicated by the proposed model are briefly discussed as an outlook.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132610373","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651682
Sejun Kim, Sang-Young Kim, B. Lee, K. Kim, H. Youn
Unlike the traditional networking infrastructure, the software defined network (SDN) separates the network control function from the data transmission function. SDN of a large geographical area requires multiple controllers rather than a single centralized one, and controller provisioning has a significant impact on the network performance. In this paper we propose a novel load balancing scheme with switch migration to effectively solve the dynamic controller provisioning problem (DCPP) for SDN. The proposed scheme employs a meta-heuristic approach based on harmony search and K-means clustering of the switches. The proposed scheme is evaluated by computer simulation in terms of load balancing accuracy, and it turns out to be superior to the existing harmony search algorithm.
{"title":"Load Balancing for Distributed SDN with Harmony Search","authors":"Sejun Kim, Sang-Young Kim, B. Lee, K. Kim, H. Youn","doi":"10.1109/CCNC.2019.8651682","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651682","url":null,"abstract":"Unlike the traditional networking infrastructure, the software defined network (SDN) separates the network control function from the data transmission function. SDN of a large geographical area requires multiple controllers rather than a single centralized one, and controller provisioning has a significant impact on the network performance. In this paper we propose a novel load balancing scheme with switch migration to effectively solve the dynamic controller provisioning problem (DCPP) for SDN. The proposed scheme employs a meta-heuristic approach based on harmony search and K-means clustering of the switches. The proposed scheme is evaluated by computer simulation in terms of load balancing accuracy, and it turns out to be superior to the existing harmony search algorithm.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133895094","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651769
Ismail Uluturk, Ismail Uysal, Kwang-Cheng Chen
Aerial deployment of access points (APs) to network infrastructure has been shown to be an effective technological solution for rapidly supplying networking services in diverse scenarios, particularly post-disaster networking after major hurricane, tsunami, and earthquake events, or for the purposes of homeland security. A straightforward yet helpful method for deployment of APs in this emerging technology is to consider the problem in two 2D planes, one for users and another for APs. However, considering the need for effectively connecting low-power user devices that may suffer from severe fading due to the blocking of line-of-sight(LoS) transmissions, genuine 3D deployment is very desirable, even though a simpler form of it had been mathematically an open problem until 2017 for 400 years. To meet the engineering requirements, we first leverage 3D random geometric graphs (RGG) to develop the joint optimization of 3D AP placement with a given number of APs for proper coverage. We further propose a computationally-efficient iterative algorithm to effectively deploy the adequate number of APs in 3D space and respond to dynamics of such wireless networks. Our simulations demonstrate the superior performance of this genuine 3D placement of APs over traditional approaches when considering connections for user devices, particularly for larger number of APs in rapid deployment.
{"title":"Efficient 3D Placement of Access Points in an Aerial Wireless Network","authors":"Ismail Uluturk, Ismail Uysal, Kwang-Cheng Chen","doi":"10.1109/CCNC.2019.8651769","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651769","url":null,"abstract":"Aerial deployment of access points (APs) to network infrastructure has been shown to be an effective technological solution for rapidly supplying networking services in diverse scenarios, particularly post-disaster networking after major hurricane, tsunami, and earthquake events, or for the purposes of homeland security. A straightforward yet helpful method for deployment of APs in this emerging technology is to consider the problem in two 2D planes, one for users and another for APs. However, considering the need for effectively connecting low-power user devices that may suffer from severe fading due to the blocking of line-of-sight(LoS) transmissions, genuine 3D deployment is very desirable, even though a simpler form of it had been mathematically an open problem until 2017 for 400 years. To meet the engineering requirements, we first leverage 3D random geometric graphs (RGG) to develop the joint optimization of 3D AP placement with a given number of APs for proper coverage. We further propose a computationally-efficient iterative algorithm to effectively deploy the adequate number of APs in 3D space and respond to dynamics of such wireless networks. Our simulations demonstrate the superior performance of this genuine 3D placement of APs over traditional approaches when considering connections for user devices, particularly for larger number of APs in rapid deployment.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134264177","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651836
Jithin Jagannath, Sean Furman, Anu Jagannath, A. Drozd
In this paper, we present the preliminary work towards providing a complete end-to-end solution that can connect survivors of a disaster with each other and public safety authorities using a completely self-sufficient ad hoc network. Accordingly, we develop a Heterogeneous Efficient Low Power Radio (HELPER) that acts as a WiFi (Wireless Fidelity) access point for end-users to connect using custom application. These HELPERs then coordinate with each other to form a LoRa based ad hoc network. The proposed solution will use a distributed optimized cross-layer routing algorithm that aims to maximize the network lifetime. This aspect is critical especially in energy-limited scenarios after a disaster. Some of the envisioned services include text and voice messages, live map updates, ability to send distress messages (like 911 calls) to authorities. HELPER network can also be used by authorities to remotely monitor the connectivity of the affected area, alert users of imminent dangers and share resource information. We intend to provide resources (code and instructions) that will enable the researchers of the community to set up a HELPER in a cost-effective (< $ 150) manner using commercial off-the-self components and advance it further. Overall, we hope this technology will become instrumental in improving the efficiency and effectiveness of public safety activities.
{"title":"Energy Efficient Ad Hoc Networking Devices for Off-the-Grid Public Safety Networks","authors":"Jithin Jagannath, Sean Furman, Anu Jagannath, A. Drozd","doi":"10.1109/CCNC.2019.8651836","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651836","url":null,"abstract":"In this paper, we present the preliminary work towards providing a complete end-to-end solution that can connect survivors of a disaster with each other and public safety authorities using a completely self-sufficient ad hoc network. Accordingly, we develop a Heterogeneous Efficient Low Power Radio (HELPER) that acts as a WiFi (Wireless Fidelity) access point for end-users to connect using custom application. These HELPERs then coordinate with each other to form a LoRa based ad hoc network. The proposed solution will use a distributed optimized cross-layer routing algorithm that aims to maximize the network lifetime. This aspect is critical especially in energy-limited scenarios after a disaster. Some of the envisioned services include text and voice messages, live map updates, ability to send distress messages (like 911 calls) to authorities. HELPER network can also be used by authorities to remotely monitor the connectivity of the affected area, alert users of imminent dangers and share resource information. We intend to provide resources (code and instructions) that will enable the researchers of the community to set up a HELPER in a cost-effective (< $ 150) manner using commercial off-the-self components and advance it further. Overall, we hope this technology will become instrumental in improving the efficiency and effectiveness of public safety activities.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121808723","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651824
Chunchao Liang, Chang Liu, Ying Li
Information exchange between distant nodes is the basis for all functionalities of a wireless ad hoc network. To effectively transmit a packet from one node to other distant nodes, the key is messenger discovery. It is important for a sender to find sufficient but not excessive direct neighboring nodes as messengers. On one hand, the messengers should be distant from the sender but not too far away. On the other hand, the messengers should be far from each other. However, the nature of the wireless ad hoc networks makes this mission a great challenge. In this paper, considering limited energy resource and the nature of ad hoc networks, we review the previous protocols and propose a new protocol, exploiting Erasure Coding for messenger discovery. Our proposed protocol is stateless and works in a distributed manner. In each messenger discovery process, the sender encodes a message into multiple packets with erasure coding and broadcasts the packets until it finds enough messengers activated. The receivers decide whether they should act as messengers or not, based on the percentage of received packets and the number of activated messengers. Mathematical analysis and simulations verifies the viability of our protocol, and shows the superiorities of our protocol.
{"title":"Discovering Messengers with Erasure Coding for Communication in Wireless Ad hoc Networks","authors":"Chunchao Liang, Chang Liu, Ying Li","doi":"10.1109/CCNC.2019.8651824","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651824","url":null,"abstract":"Information exchange between distant nodes is the basis for all functionalities of a wireless ad hoc network. To effectively transmit a packet from one node to other distant nodes, the key is messenger discovery. It is important for a sender to find sufficient but not excessive direct neighboring nodes as messengers. On one hand, the messengers should be distant from the sender but not too far away. On the other hand, the messengers should be far from each other. However, the nature of the wireless ad hoc networks makes this mission a great challenge. In this paper, considering limited energy resource and the nature of ad hoc networks, we review the previous protocols and propose a new protocol, exploiting Erasure Coding for messenger discovery. Our proposed protocol is stateless and works in a distributed manner. In each messenger discovery process, the sender encodes a message into multiple packets with erasure coding and broadcasts the packets until it finds enough messengers activated. The receivers decide whether they should act as messengers or not, based on the percentage of received packets and the number of activated messengers. Mathematical analysis and simulations verifies the viability of our protocol, and shows the superiorities of our protocol.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129198129","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651814
Ryutaro Ushigome, Mio Suzuki, Tao Ban, Takeshi Takahashi, D. Inoue, T. Matsuda, M. Sonoda
Social media is regarded as one of the most timely sources of information. Nevertheless, malicious users may misuse such media, and it may lead to severe incidents. Countermeasures to remove malicious user accounts and remove untrusted information need to be built. Various studies have been conducted until now. In this paper, we first provide an overview of recent work in this domain and then introduce our approach. Our preliminary experiment shows the feasibility of the research and discusses the future direction of this research.
{"title":"Establishing Trusted and Timely Information Source using Social Media Services","authors":"Ryutaro Ushigome, Mio Suzuki, Tao Ban, Takeshi Takahashi, D. Inoue, T. Matsuda, M. Sonoda","doi":"10.1109/CCNC.2019.8651814","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651814","url":null,"abstract":"Social media is regarded as one of the most timely sources of information. Nevertheless, malicious users may misuse such media, and it may lead to severe incidents. Countermeasures to remove malicious user accounts and remove untrusted information need to be built. Various studies have been conducted until now. In this paper, we first provide an overview of recent work in this domain and then introduce our approach. Our preliminary experiment shows the feasibility of the research and discusses the future direction of this research.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127984552","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651850
N. Blanc, Zhan Liu, O. Ertz, Diego Rojas, R. Sandoz, M. Sokhn, J. Ingensand, J. Loubier
The availability of global and scalable tools to assess disabled pedestrian level of service (DPLoS) is a real need, yet still a challenge in today’s world. This is due to the lack of tools that can ease the measurement of a level of service adapted to disabled people, and also to the limitation concerns about the availability of information regarding the existing level of service, especially in real time. This paper describes preliminary results to progress on those needs. It also includes a design for a navigation tool that can help a disabled person move around a city by suggesting the most adapted routes according to the person’s disabilities. The main topics are how to use advanced computer vision technologies, and how to benefit from the prevalence of handheld devices. Our approach intends to show how crowdsourcing techniques can improve data quality by gathering and combining up-to-date data with valuable field observations.
{"title":"Building a Crowdsourcing based Disabled Pedestrian Level of Service routing application using Computer Vision and Machine Learning","authors":"N. Blanc, Zhan Liu, O. Ertz, Diego Rojas, R. Sandoz, M. Sokhn, J. Ingensand, J. Loubier","doi":"10.1109/CCNC.2019.8651850","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651850","url":null,"abstract":"The availability of global and scalable tools to assess disabled pedestrian level of service (DPLoS) is a real need, yet still a challenge in today’s world. This is due to the lack of tools that can ease the measurement of a level of service adapted to disabled people, and also to the limitation concerns about the availability of information regarding the existing level of service, especially in real time. This paper describes preliminary results to progress on those needs. It also includes a design for a navigation tool that can help a disabled person move around a city by suggesting the most adapted routes according to the person’s disabilities. The main topics are how to use advanced computer vision technologies, and how to benefit from the prevalence of handheld devices. Our approach intends to show how crowdsourcing techniques can improve data quality by gathering and combining up-to-date data with valuable field observations.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123079683","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651868
Jonathan Rogers, Dylan Simmons, Milesh Shah, Connor Rowland, Yi Shang
From SurveyMonkey to Google Forms, online surveys have become a cornerstone of modern research. However, these survey platforms lack the ability to provide advanced analysis to researchers, often requiring expensive third-party analytics software to rectify their shortcomings. We propose to solve this problem by adding data analysis capabilities onto TigerAware, an existing data collection platform. TigerAware offers a generic and customizable tool which allows researchers without technical expertise to create, manage, and deploy custom mobile surveys to participants in real-time. We seek to add data analysis functionalities to the TigerAware platform ranging from basic statistics functions to emotion recognition via deep learning. Our analysis platform uses data collected by TigerAware to give researchers real-time analytics throughout the duration of their study. Through our additions to the TigerAware platform, we present a novel all-in-one tool for researchers to facilitate effective survey creation, survey administration, data collection, and data analysis.
{"title":"Deep Learning at Your Fingertips","authors":"Jonathan Rogers, Dylan Simmons, Milesh Shah, Connor Rowland, Yi Shang","doi":"10.1109/CCNC.2019.8651868","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651868","url":null,"abstract":"From SurveyMonkey to Google Forms, online surveys have become a cornerstone of modern research. However, these survey platforms lack the ability to provide advanced analysis to researchers, often requiring expensive third-party analytics software to rectify their shortcomings. We propose to solve this problem by adding data analysis capabilities onto TigerAware, an existing data collection platform. TigerAware offers a generic and customizable tool which allows researchers without technical expertise to create, manage, and deploy custom mobile surveys to participants in real-time. We seek to add data analysis functionalities to the TigerAware platform ranging from basic statistics functions to emotion recognition via deep learning. Our analysis platform uses data collected by TigerAware to give researchers real-time analytics throughout the duration of their study. Through our additions to the TigerAware platform, we present a novel all-in-one tool for researchers to facilitate effective survey creation, survey administration, data collection, and data analysis.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132083173","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 : 2019-01-01DOI: 10.1109/CCNC.2019.8651716
Keisuke Maesako, Yumi Takaki, Tomio Kamada, C. Ohta
In recent years, wireless mesh networks (WMNs) have become popular because of their wide coverage areas and high fault tolerance. Although unlicensed-band off-the-shelf wireless devices based on IEEE 802.11 are widely deployed, WMNs based on IEEE 802.11 suffer from degradation of throughput owing to the hidden node problem. To mitigate this problem, in this study, we developed a new routing metric called the “Asymmetric Hidden node problem Aware routing Metric (AHAM).” AHAM enables a new flow to establish a source-destination path that largely avoids not only interference with hidden nodes of existing flows but also making hidden nodes on that path interfere with existing flows. This is because the hidden node problem can asymmetrically impact throughput between flows when new flows are established. As a response, AHAM aims to estimate the influence of hidden nodes accurately and compensate for how both the new and existing flows influence each other. Simulation results showed that AHAM realizes high throughput while maintaining network fairness compared with other metrics.
{"title":"Asymmetric Hidden Node Problem Aware Routing Metric for Wireless Mesh Networks","authors":"Keisuke Maesako, Yumi Takaki, Tomio Kamada, C. Ohta","doi":"10.1109/CCNC.2019.8651716","DOIUrl":"https://doi.org/10.1109/CCNC.2019.8651716","url":null,"abstract":"In recent years, wireless mesh networks (WMNs) have become popular because of their wide coverage areas and high fault tolerance. Although unlicensed-band off-the-shelf wireless devices based on IEEE 802.11 are widely deployed, WMNs based on IEEE 802.11 suffer from degradation of throughput owing to the hidden node problem. To mitigate this problem, in this study, we developed a new routing metric called the “Asymmetric Hidden node problem Aware routing Metric (AHAM).” AHAM enables a new flow to establish a source-destination path that largely avoids not only interference with hidden nodes of existing flows but also making hidden nodes on that path interfere with existing flows. This is because the hidden node problem can asymmetrically impact throughput between flows when new flows are established. As a response, AHAM aims to estimate the influence of hidden nodes accurately and compensate for how both the new and existing flows influence each other. Simulation results showed that AHAM realizes high throughput while maintaining network fairness compared with other metrics.","PeriodicalId":285899,"journal":{"name":"2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128496471","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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