Pub Date : 2017-05-08DOI: 10.23919/INM.2017.7987362
Patrick Bosch, Jeroen Wyffels, B. Braem, Steven Latré
The popularity of the IEEE 802.11 (Wi-Fi) standard has resulted in a plethora of hotspot deployments. While home hotspots offer high and consistent performance, at large-scale events such as conferences and festivals, Wi-Fi performance is often poor and highly fluctuating. There are several factors explaining this increased difficulty: the required scale, the complexity of backhaul network topologies, the density of devices connected to the access point (AP), and the interference caused by both people and radio frequency (RF) equipment. While these factors are all known to degrade the performance of public hotspots, little is known about the actual performance of IEEE 802.11 at large-scale events. In this paper, we present the results of quantitative Wi-Fi performance measurement study undertaken at a music festival with 80,000 visitors over a geographical area of 0.3 square kilometres. Two separate networks were constructed for this study. The first was an IEEE 802.11n-based wireless mesh consisting of 37 devices in 15 nodes working as a network backhaul and the second an IEEE 802.11n/ac-based public hotspot that was accessible by the festival goers. We characterise the performance of the wireless spectrum and illustrate the impact of interference factors such as crowds and RF equipment. Finally, we report on the results of the deployment of a public hotspot at the festival, focusing more on application-layer metrics parameters such as user experience and session statistics. The results show that the interference at such events is so high that adaptations to the protocol configuration are needed to improve performance.
{"title":"How is your event Wi-Fi doing? Performance measurements of large-scale and dense IEEE 802.11n/ac networks","authors":"Patrick Bosch, Jeroen Wyffels, B. Braem, Steven Latré","doi":"10.23919/INM.2017.7987362","DOIUrl":"https://doi.org/10.23919/INM.2017.7987362","url":null,"abstract":"The popularity of the IEEE 802.11 (Wi-Fi) standard has resulted in a plethora of hotspot deployments. While home hotspots offer high and consistent performance, at large-scale events such as conferences and festivals, Wi-Fi performance is often poor and highly fluctuating. There are several factors explaining this increased difficulty: the required scale, the complexity of backhaul network topologies, the density of devices connected to the access point (AP), and the interference caused by both people and radio frequency (RF) equipment. While these factors are all known to degrade the performance of public hotspots, little is known about the actual performance of IEEE 802.11 at large-scale events. In this paper, we present the results of quantitative Wi-Fi performance measurement study undertaken at a music festival with 80,000 visitors over a geographical area of 0.3 square kilometres. Two separate networks were constructed for this study. The first was an IEEE 802.11n-based wireless mesh consisting of 37 devices in 15 nodes working as a network backhaul and the second an IEEE 802.11n/ac-based public hotspot that was accessible by the festival goers. We characterise the performance of the wireless spectrum and illustrate the impact of interference factors such as crowds and RF equipment. Finally, we report on the results of the deployment of a public hotspot at the festival, focusing more on application-layer metrics parameters such as user experience and session statistics. The results show that the interference at such events is so high that adaptations to the protocol configuration are needed to improve performance.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132573363","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 : 2017-05-08DOI: 10.23919/INM.2017.7987369
Luís Rosa, T. Cruz, P. Simões, E. Monteiro, Leonid Lev
As Supervisory Control and Data Acquisition (SCADA) and Industrial and Automation Control System (IACS) architectures became more open and interconnected, some of their remotely controlled processes also became more exposed to cyber threats. Aspects such as the use of mature technologies and legacy equipment or even the unforeseen consequences of bridging IACS with external networks have contributed to this situation. This situation prompted the involvement of governmental, industrial and research organizations, as well as standardization entities, in order to create and promote a series of recommendations and standards for IACS cyber-security. Despite those efforts, which are mostly focused on prevention and mitigation, existing literature still lacks attack descriptions that can be reused to reproduce and further research specific use cases and scenarios of security incidents, useful for improving and developing new security detection strategies. In this paper, we describe the implementation of a set of attacks targeting a SCADA hybrid testbed that reproduces an electrical grid for energy distribution (medium and high voltage). This environment makes use of real SCADA equipment to faithfully reproduce a real operational deployment, providing a better insight into less evident SCADA- and device-specificities.
{"title":"Attacking SCADA systems: A practical perspective","authors":"Luís Rosa, T. Cruz, P. Simões, E. Monteiro, Leonid Lev","doi":"10.23919/INM.2017.7987369","DOIUrl":"https://doi.org/10.23919/INM.2017.7987369","url":null,"abstract":"As Supervisory Control and Data Acquisition (SCADA) and Industrial and Automation Control System (IACS) architectures became more open and interconnected, some of their remotely controlled processes also became more exposed to cyber threats. Aspects such as the use of mature technologies and legacy equipment or even the unforeseen consequences of bridging IACS with external networks have contributed to this situation. This situation prompted the involvement of governmental, industrial and research organizations, as well as standardization entities, in order to create and promote a series of recommendations and standards for IACS cyber-security. Despite those efforts, which are mostly focused on prevention and mitigation, existing literature still lacks attack descriptions that can be reused to reproduce and further research specific use cases and scenarios of security incidents, useful for improving and developing new security detection strategies. In this paper, we describe the implementation of a set of attacks targeting a SCADA hybrid testbed that reproduces an electrical grid for energy distribution (medium and high voltage). This environment makes use of real SCADA equipment to faithfully reproduce a real operational deployment, providing a better insight into less evident SCADA- and device-specificities.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"252 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121410005","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 : 2017-05-08DOI: 10.23919/INM.2017.7987422
R. Harper, P. Tee
The principal objective when monitoring compute and communications infrastructure is to minimize the Mean Time To Resolution of service-impacting incidents. Key to achieving that goal is determining which of the many alerts that are presented to an operator are likely to be the root cause of an incident. In turn this is critical in identifying which alerts should be investigated with the highest priority.
{"title":"The application of Neural Networks to predicting the root cause of service failures","authors":"R. Harper, P. Tee","doi":"10.23919/INM.2017.7987422","DOIUrl":"https://doi.org/10.23919/INM.2017.7987422","url":null,"abstract":"The principal objective when monitoring compute and communications infrastructure is to minimize the Mean Time To Resolution of service-impacting incidents. Key to achieving that goal is determining which of the many alerts that are presented to an operator are likely to be the root cause of an incident. In turn this is critical in identifying which alerts should be investigated with the highest priority.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124124912","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 : 2017-05-08DOI: 10.23919/INM.2017.7987264
Farnaz Moradi, Christofer Flinta, A. Johnsson, C. Meirosu
The popularity of container technologies and their widespread usage for building microservices demands solutions dedicated for efficient monitoring of containers and their interactions. In this paper we present ConMon, an automated system for monitoring the network performance of container-based applications. It automatically identifies newly instantiated application containers and observes passively their traffic. Based on these observations, it configures and executes monitoring functions inside adjacent monitoring containers. The system adapts the monitoring containers to changes driven by either the application or the execution platform. The evaluation results validate the feasibility of the ConMon approach and illustrate its scalability in terms of low overhead on compute resources, moderate impact on applications, and negligible impact on the background network traffic.
{"title":"ConMon: An automated container based network performance monitoring system","authors":"Farnaz Moradi, Christofer Flinta, A. Johnsson, C. Meirosu","doi":"10.23919/INM.2017.7987264","DOIUrl":"https://doi.org/10.23919/INM.2017.7987264","url":null,"abstract":"The popularity of container technologies and their widespread usage for building microservices demands solutions dedicated for efficient monitoring of containers and their interactions. In this paper we present ConMon, an automated system for monitoring the network performance of container-based applications. It automatically identifies newly instantiated application containers and observes passively their traffic. Based on these observations, it configures and executes monitoring functions inside adjacent monitoring containers. The system adapts the monitoring containers to changes driven by either the application or the execution platform. The evaluation results validate the feasibility of the ConMon approach and illustrate its scalability in terms of low overhead on compute resources, moderate impact on applications, and negligible impact on the background network traffic.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123750386","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 : 2017-05-08DOI: 10.23919/INM.2017.7987405
Marouen Mechtri, Chaima Ghribi, Oussama Soualah, D. Zeghlache
This demo presents a SFC orchestrator that provides intelligent, dynamic and automated VNFs and network deployment over heterogeneous NFV and SDN enabled Cloud environments. The proposed architecture is based on the ETSI NFV reference architecture and TOSCA standards. In this demo, reliable VNF placement and chaining is ensured using the algorithm proposed in [1] “A Link Failure Recovery Algorithm For Virtual Network Function Chaining”.
{"title":"ETSO: End-To-End SFC Orchestration Framework","authors":"Marouen Mechtri, Chaima Ghribi, Oussama Soualah, D. Zeghlache","doi":"10.23919/INM.2017.7987405","DOIUrl":"https://doi.org/10.23919/INM.2017.7987405","url":null,"abstract":"This demo presents a SFC orchestrator that provides intelligent, dynamic and automated VNFs and network deployment over heterogeneous NFV and SDN enabled Cloud environments. The proposed architecture is based on the ETSI NFV reference architecture and TOSCA standards. In this demo, reliable VNF placement and chaining is ensured using the algorithm proposed in [1] “A Link Failure Recovery Algorithm For Virtual Network Function Chaining”.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131225715","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 : 2017-05-08DOI: 10.23919/INM.2017.7987260
Karsten Molka, G. Casale
Systems for processing large scale analytical workloads are increasingly moving from on-premise setups to on-demand configurations deployed on scalable cloud infrastructures. To reduce the cost of such infrastructures, existing research focuses on developing novel methods for workload and server consolidation. In this paper, we combine analytical modeling and non-linear optimization to help cloud providers increase the energy-efficiency of in-memory database clusters in cloud environments. We model this scenario as a multi-dimensional bin-packing problem and propose a new approach based on a hybrid genetic algorithm that efficiently handles resource allocation and server assignment for a given set of in-memory databases. Our trace-driven evaluation is based on measurements from an SAP HANA in-memory system and indicates improvements between 6% and 32% over the popular best-fit decreasing heuristic.
{"title":"Energy-efficient resource allocation and provisioning for in-memory database clusters","authors":"Karsten Molka, G. Casale","doi":"10.23919/INM.2017.7987260","DOIUrl":"https://doi.org/10.23919/INM.2017.7987260","url":null,"abstract":"Systems for processing large scale analytical workloads are increasingly moving from on-premise setups to on-demand configurations deployed on scalable cloud infrastructures. To reduce the cost of such infrastructures, existing research focuses on developing novel methods for workload and server consolidation. In this paper, we combine analytical modeling and non-linear optimization to help cloud providers increase the energy-efficiency of in-memory database clusters in cloud environments. We model this scenario as a multi-dimensional bin-packing problem and propose a new approach based on a hybrid genetic algorithm that efficiently handles resource allocation and server assignment for a given set of in-memory databases. Our trace-driven evaluation is based on measurements from an SAP HANA in-memory system and indicates improvements between 6% and 32% over the popular best-fit decreasing heuristic.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114147296","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 : 2017-05-08DOI: 10.23919/INM.2017.7987400
Florian Wamser, Frank Loh, Michael Seufert, P. Tran-Gia, R. Bruschi, P. Lago
In this demonstration we will show the prospects of dynamic cloud service placement. A cloud service is implemented that manages real-time video streaming and real-time control commands for a remote controlled drone. The requirements for this cloud service are groundbreaking because the image transfer and the control commands should be transmitted in real time that the drone can be controlled smoothly by a user. The goal is to improve user QoE for streaming services and real-time control by cloud service migrations, respecting the concept of dynamic Edge Computing by means of moving computing and monitoring applications on demand close to the user and the end device.
{"title":"Dynamic cloud service placement for live video streaming with a remote-controlled drone","authors":"Florian Wamser, Frank Loh, Michael Seufert, P. Tran-Gia, R. Bruschi, P. Lago","doi":"10.23919/INM.2017.7987400","DOIUrl":"https://doi.org/10.23919/INM.2017.7987400","url":null,"abstract":"In this demonstration we will show the prospects of dynamic cloud service placement. A cloud service is implemented that manages real-time video streaming and real-time control commands for a remote controlled drone. The requirements for this cloud service are groundbreaking because the image transfer and the control commands should be transmitted in real time that the drone can be controlled smoothly by a user. The goal is to improve user QoE for streaming services and real-time control by cloud service migrations, respecting the concept of dynamic Edge Computing by means of moving computing and monitoring applications on demand close to the user and the end device.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133871303","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 : 2017-05-08DOI: 10.23919/INM.2017.7987261
Federico Larumbe, B. Sansò
This article presents a new model and a resolution algorithm, based on Tabu Search, for the assignment of Virtual Machines (VMs) to servers in a data center. We propose a Mixed Integer Programming (MIP) model that optimizes the Quality of Service (QoS) and power consumption of applications, taking into account their communication traffic and dynamic aspects. A hierarchic method and a Tabu Search heuristic that considers the network topology are developed to solve cases with realistic sizes—e.g., a data center with 1600 servers per pod, for up to 128,000 total servers—. The method specifically considers the optimal mapping of the application graph into the data center network. The proposed scheduler is compared with 1) a static method that does not consider workload variations, and 2) the first-fit policy as a sample of methods that do not consider communication traffic among VMs.
{"title":"Elastic, on-line and network aware Virtual Machine placement within a data center","authors":"Federico Larumbe, B. Sansò","doi":"10.23919/INM.2017.7987261","DOIUrl":"https://doi.org/10.23919/INM.2017.7987261","url":null,"abstract":"This article presents a new model and a resolution algorithm, based on Tabu Search, for the assignment of Virtual Machines (VMs) to servers in a data center. We propose a Mixed Integer Programming (MIP) model that optimizes the Quality of Service (QoS) and power consumption of applications, taking into account their communication traffic and dynamic aspects. A hierarchic method and a Tabu Search heuristic that considers the network topology are developed to solve cases with realistic sizes—e.g., a data center with 1600 servers per pod, for up to 128,000 total servers—. The method specifically considers the optimal mapping of the application graph into the data center network. The proposed scheduler is compared with 1) a static method that does not consider workload variations, and 2) the first-fit policy as a sample of methods that do not consider communication traffic among VMs.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130370210","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 : 2017-05-08DOI: 10.23919/INM.2017.7987376
T. Bocek, B. Rodrigues, T. Strasser, B. Stiller
Blockchains are on the top of the Gartner Hype Cycle 2016 and many start-ups are integrating blockchains into their technology portfolio. While blockchains have emerged in the context of financial applications, non-financial application areas are of interest as well. In this paper, modum.io is presented, a start-up that uses IoT (Internet of Things) sensor devices leveraging blockchain technology to assert data immutability and public accessibility of temperature records, while reducing operational costs in the pharmaceutical supply-chain. The medical industry has many complex and strict environmental control process (e.g., temperature and humidity) to ensure quality control and regulatory compliance over the transport of medical products. The sensor devices monitor the temperature of each parcel during the shipment to fully ensure GDP regulations. All data is transferred to the blockchain where a smart contract assesses against the product attributes. As modum.io is not the only non-financial start-up working with blockchains, a list of areas and other start-ups is provided that aim to reduce bureaucracy, distribute the infrastructure, and saving costs using blockchains.
{"title":"Blockchains everywhere - a use-case of blockchains in the pharma supply-chain","authors":"T. Bocek, B. Rodrigues, T. Strasser, B. Stiller","doi":"10.23919/INM.2017.7987376","DOIUrl":"https://doi.org/10.23919/INM.2017.7987376","url":null,"abstract":"Blockchains are on the top of the Gartner Hype Cycle 2016 and many start-ups are integrating blockchains into their technology portfolio. While blockchains have emerged in the context of financial applications, non-financial application areas are of interest as well. In this paper, modum.io is presented, a start-up that uses IoT (Internet of Things) sensor devices leveraging blockchain technology to assert data immutability and public accessibility of temperature records, while reducing operational costs in the pharmaceutical supply-chain. The medical industry has many complex and strict environmental control process (e.g., temperature and humidity) to ensure quality control and regulatory compliance over the transport of medical products. The sensor devices monitor the temperature of each parcel during the shipment to fully ensure GDP regulations. All data is transferred to the blockchain where a smart contract assesses against the product attributes. As modum.io is not the only non-financial start-up working with blockchains, a list of areas and other start-ups is provided that aim to reduce bureaucracy, distribute the infrastructure, and saving costs using blockchains.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121165551","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 : 2017-05-08DOI: 10.23919/INM.2017.7987413
Airton Ishimori, E. Cerqueira, A. Abelém
Software-Defined Networking (SDN) has turned the Data Center Network (DCN) environment into a more flexible one by decoupling control plane from data plane, allowing an innovative and easily extensible network management solutions. Nowadays, OpenFlow is the most successful protocol for SDN. However, SDN based on OpenFlow protocol presents performance issues on forwarding table increasing and packet match cost. Our proposal named Tag-and-Forward (TF) is a data plane that reduces the number of flow table required in the Fat-Tree software-defined DCNs to optimize forwarding. The results noticebly outperformed RTT and packet transmission rate when compared to usual OpenFlow data plane.
{"title":"Tag-and-Forward: A source-routing enabled data plane for OpenFlow Fat-Tree Networks","authors":"Airton Ishimori, E. Cerqueira, A. Abelém","doi":"10.23919/INM.2017.7987413","DOIUrl":"https://doi.org/10.23919/INM.2017.7987413","url":null,"abstract":"Software-Defined Networking (SDN) has turned the Data Center Network (DCN) environment into a more flexible one by decoupling control plane from data plane, allowing an innovative and easily extensible network management solutions. Nowadays, OpenFlow is the most successful protocol for SDN. However, SDN based on OpenFlow protocol presents performance issues on forwarding table increasing and packet match cost. Our proposal named Tag-and-Forward (TF) is a data plane that reduces the number of flow table required in the Fat-Tree software-defined DCNs to optimize forwarding. The results noticebly outperformed RTT and packet transmission rate when compared to usual OpenFlow data plane.","PeriodicalId":119633,"journal":{"name":"2017 IFIP/IEEE Symposium on Integrated Network and Service Management (IM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131391729","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：