Pub Date : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880816
Vinh Hoang Son Le, C. A. Nour, E. Boutillon, C. Douillard
Puncturing a low-rate convolutional code to generate a high-rate code has some drawback in terms of hardware implementation. In fact, a Maximum A-Posteriori (MAP) decoder based on the original trellis will then have a decoding throughput close to the decoding throughput of the mother non-punctured code. A solution to overcome this limitation is to perform MAP decoding on the dual trellis of a high-rate equivalent convolutional code. In the literature, dual trellis construction is only reported for specific punctured codes with rate $k/(k+1)$. In this paper, we propose a multi-step method to construct the equivalent dual code defined by the corresponding dual trellis for any punctured code. First, the equivalent nonsystematic generator matrix of the high-rate punctured code is derived. Then, the reciprocal parity-check matrix for the construction of the dual trellis is deduced. As a result, we show that the dual-MAP algorithm applied on the newly constructed dual trellis yields the same performance as the original MAP algorithm while allowing the decoder to achieve a higher throughput. When applied to turbo codes, this method enables highly efficient implementations of high-throughput high-rate turbo decoders.
{"title":"Dual Trellis Construction for High-Rate Punctured Convolutional Codes","authors":"Vinh Hoang Son Le, C. A. Nour, E. Boutillon, C. Douillard","doi":"10.1109/PIMRCW.2019.8880816","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880816","url":null,"abstract":"Puncturing a low-rate convolutional code to generate a high-rate code has some drawback in terms of hardware implementation. In fact, a Maximum A-Posteriori (MAP) decoder based on the original trellis will then have a decoding throughput close to the decoding throughput of the mother non-punctured code. A solution to overcome this limitation is to perform MAP decoding on the dual trellis of a high-rate equivalent convolutional code. In the literature, dual trellis construction is only reported for specific punctured codes with rate $k/(k+1)$. In this paper, we propose a multi-step method to construct the equivalent dual code defined by the corresponding dual trellis for any punctured code. First, the equivalent nonsystematic generator matrix of the high-rate punctured code is derived. Then, the reciprocal parity-check matrix for the construction of the dual trellis is deduced. As a result, we show that the dual-MAP algorithm applied on the newly constructed dual trellis yields the same performance as the original MAP algorithm while allowing the decoder to achieve a higher throughput. When applied to turbo codes, this method enables highly efficient implementations of high-throughput high-rate turbo decoders.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122901552","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880820
Frank Engelhardt, M. Günes
The future Tactile Internet is expected to enable ultra-low-latency haptic communication in realtime between peers over arbitrary distances. This vision is currently highly based on the existing Internet Backbone and the upcoming 5G (and beyond) mobile communication networks. However, WiFi networks that are based on the IEEE 802.11 standard have spread widely and will be undiminishedly part of future networks. We derive a probabilistic model for estimation of latency in uncongested 802.11-based Wireless Multi-Hop Networks (WMHNs) with arbitrary topology. The model parameters are: (i) the data rate of the nodes, (ii) the packet error rate, (iii) the sending probability of the nodes, and (iv) the distribution of the queueing delay. In simulations our preliminary model can accurately predict both the minimum and maximum observed delays with multiple haptic flows present.
{"title":"Modeling Delay of Haptic Data in CSMA-based Wireless Multi-Hop Networks: A Probabilistic Approach","authors":"Frank Engelhardt, M. Günes","doi":"10.1109/PIMRCW.2019.8880820","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880820","url":null,"abstract":"The future Tactile Internet is expected to enable ultra-low-latency haptic communication in realtime between peers over arbitrary distances. This vision is currently highly based on the existing Internet Backbone and the upcoming 5G (and beyond) mobile communication networks. However, WiFi networks that are based on the IEEE 802.11 standard have spread widely and will be undiminishedly part of future networks. We derive a probabilistic model for estimation of latency in uncongested 802.11-based Wireless Multi-Hop Networks (WMHNs) with arbitrary topology. The model parameters are: (i) the data rate of the nodes, (ii) the packet error rate, (iii) the sending probability of the nodes, and (iv) the distribution of the queueing delay. In simulations our preliminary model can accurately predict both the minimum and maximum observed delays with multiple haptic flows present.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130305490","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880827
M. Kanaan, Muhammed Cil
In this study, wireless capsule endoscopy, which is used for imaging of the human gastrointestinal tract, is discussed. Magnetic localization technique is considered for estimating location and orientation of the capsule, owing to its potential to yield more accurate estimates. It is assumed that a cylindrical magnet wrapped around the capsule is present. The localization accuracy of this method was analyzed by Cramer-Rao lower bound method, which is alower bound on unbiased estimates. Changes in the Cramer-Rao Lower Bound were investigated under different scenarios.
{"title":"Cramer-Rao Lower Bounds for Magnetic Localization of a Wireless Capsule Endoscope based on the Magnetic Dipole Model","authors":"M. Kanaan, Muhammed Cil","doi":"10.1109/PIMRCW.2019.8880827","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880827","url":null,"abstract":"In this study, wireless capsule endoscopy, which is used for imaging of the human gastrointestinal tract, is discussed. Magnetic localization technique is considered for estimating location and orientation of the capsule, owing to its potential to yield more accurate estimates. It is assumed that a cylindrical magnet wrapped around the capsule is present. The localization accuracy of this method was analyzed by Cramer-Rao lower bound method, which is alower bound on unbiased estimates. Changes in the Cramer-Rao Lower Bound were investigated under different scenarios.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"45 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113992989","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880846
Z. Bilgin, E. Tomur, M. Ersoy, Elif Ustundag Soykan
Smart Grid has been attracting more interest than ever thanks to emergence of enabling technologies such as 5G and IoT. Yet, there are some long-standing privacy concerns about revealing habits and lifestyles of people from fine-grained power consumption data collected through smart meters. In this context, the contribution of this work is twofold: First, we empirically demonstrate how appliance-level fine-grained power consumption data can reveal households' routines simply using probability density estimations derived from consumption data without requiring any complex analysis. Second, we point out that appliance types can be identified in a targeted house using circuit-level consumption data of other houses. We show how machine learning can be used maliciously to realize this threat in an automatic manner and achieve high success rate even with limited amount of training data on the public REDD dataset. In addition, we provide discussions on possible countermeasures against the threats examined in this study.
{"title":"Statistical Appliance Inference in the Smart Grid by Machine Learning","authors":"Z. Bilgin, E. Tomur, M. Ersoy, Elif Ustundag Soykan","doi":"10.1109/PIMRCW.2019.8880846","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880846","url":null,"abstract":"Smart Grid has been attracting more interest than ever thanks to emergence of enabling technologies such as 5G and IoT. Yet, there are some long-standing privacy concerns about revealing habits and lifestyles of people from fine-grained power consumption data collected through smart meters. In this context, the contribution of this work is twofold: First, we empirically demonstrate how appliance-level fine-grained power consumption data can reveal households' routines simply using probability density estimations derived from consumption data without requiring any complex analysis. Second, we point out that appliance types can be identified in a targeted house using circuit-level consumption data of other houses. We show how machine learning can be used maliciously to realize this threat in an automatic manner and achieve high success rate even with limited amount of training data on the public REDD dataset. In addition, we provide discussions on possible countermeasures against the threats examined in this study.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125433594","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880830
Memduh Suveren, M. Kanaan
In this study, magnetic positioning process is performed by WCE method which is mostly preferred in recent years. In order to make 5D magnetic positioning possible, two different algorithms were used to solve nonlinear mathematical dipole equations; Artificial Bee Colony algorithm and Levenberg-Marquardt method. In case of using both algorithms separately and hybrid, performance comparison was made and the effect of noise on positioning error was investigated. As a result, we obtained a position error of less than 0.65 mm and orientation error of less than 0.8° in the absence of noise and in case of noise addition, we had an average position error of 6.45 mm and a 9% angle error.
{"title":"5D Magnetic Localization for Wireless Capsule Endoscopy Using the Levenberg-Marquardt Method and Artificial Bee Colony Algorithm","authors":"Memduh Suveren, M. Kanaan","doi":"10.1109/PIMRCW.2019.8880830","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880830","url":null,"abstract":"In this study, magnetic positioning process is performed by WCE method which is mostly preferred in recent years. In order to make 5D magnetic positioning possible, two different algorithms were used to solve nonlinear mathematical dipole equations; Artificial Bee Colony algorithm and Levenberg-Marquardt method. In case of using both algorithms separately and hybrid, performance comparison was made and the effect of noise on positioning error was investigated. As a result, we obtained a position error of less than 0.65 mm and orientation error of less than 0.8° in the absence of noise and in case of noise addition, we had an average position error of 6.45 mm and a 9% angle error.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"207 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124661848","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880822
Lars Van De Kamp, Chibuike Ugwuoke, Z. Erkin
In a society where digital data has become ubiquitous and has been projected to continue in this trajectory for the foreseeable future, machine learning has become a dependable tool to aid in analyzing these big datasets. However, where the data or machine learning algorithms are considered to be privacy-sensitive, one is then faced with the challenge of preserving the utility of machine learning in a privacy-preserving setting. In this paper, we focus on a use case where decentralized parties have privately owned machine learning algorithms, and would want to jointly generate a public model while not violating the privacy of their individual models, and data. We present ECONoMy: a privacy-preserving protocol that supports collaborative learning using an ensemble technique. Set in an honest-but-curious security model, ECONoMy is lightweight and provides efficiency and privacy in settings with large participant such as with IoT devices.
{"title":"ECONoMy: Ensemble Collaborative Learning Using Masking","authors":"Lars Van De Kamp, Chibuike Ugwuoke, Z. Erkin","doi":"10.1109/PIMRCW.2019.8880822","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880822","url":null,"abstract":"In a society where digital data has become ubiquitous and has been projected to continue in this trajectory for the foreseeable future, machine learning has become a dependable tool to aid in analyzing these big datasets. However, where the data or machine learning algorithms are considered to be privacy-sensitive, one is then faced with the challenge of preserving the utility of machine learning in a privacy-preserving setting. In this paper, we focus on a use case where decentralized parties have privately owned machine learning algorithms, and would want to jointly generate a public model while not violating the privacy of their individual models, and data. We present ECONoMy: a privacy-preserving protocol that supports collaborative learning using an ensemble technique. Set in an honest-but-curious security model, ECONoMy is lightweight and provides efficiency and privacy in settings with large participant such as with IoT devices.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123278225","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880817
Haya Shajaiah, A. Sengupta, A. Abdel-Hadi, T. Clancy
We investigate the performance of uplink communications in Internet-of-Things (IoT) networks under passive attacks from eavesdroppers capable of intercepting individual links. An industrial IoT network is studied where multiple sensor classes, each with a dedicated local access point (LAP), are connected to one or more small cell access points (SAP) which in turn are connected to a central server. The server interfaces the IoT network to industrial sensor monitoring systems which periodically request sensor readings. We propose a unique attack resilient IoT sensor reporting model and study the performance of this system under strict latency as well as secrecy constraints. We show through simulation results how the proposed model behaves in different scenarios and compare the resilience to attack capability for the different cases.
{"title":"Performance Trade-offs in IoT Uplink Networks under Secrecy Constraints","authors":"Haya Shajaiah, A. Sengupta, A. Abdel-Hadi, T. Clancy","doi":"10.1109/PIMRCW.2019.8880817","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880817","url":null,"abstract":"We investigate the performance of uplink communications in Internet-of-Things (IoT) networks under passive attacks from eavesdroppers capable of intercepting individual links. An industrial IoT network is studied where multiple sensor classes, each with a dedicated local access point (LAP), are connected to one or more small cell access points (SAP) which in turn are connected to a central server. The server interfaces the IoT network to industrial sensor monitoring systems which periodically request sensor readings. We propose a unique attack resilient IoT sensor reporting model and study the performance of this system under strict latency as well as secrecy constraints. We show through simulation results how the proposed model behaves in different scenarios and compare the resilience to attack capability for the different cases.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126457602","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 : 2019-09-01DOI: 10.1109/pimrcw.2019.8880835
{"title":"[Copyright notice]","authors":"","doi":"10.1109/pimrcw.2019.8880835","DOIUrl":"https://doi.org/10.1109/pimrcw.2019.8880835","url":null,"abstract":"","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"47 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131861373","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880845
Huan Wu, Eddy Hum, Hoda ShahMohammadian
With significant progress of full duplex technology, next generation wireless communication systems are moving toward application of full duplex enabled networks. The main challenges for the deployment of such networks is handling the additional interferences between nodes and devices. In an early deployment scenario where the base stations operate in full duplex mode while the user equipment remain in the half duplex mode, the mutual interference between the paired UEs of full duplex scheduling is a critical issue and needs to be well addressed in order to capitalize on the gain of a full duplex system. In this paper, we present design principles of a probing signal SUIM and propose a practical and reliable solution for UE-to-UE interference measurement in a full duplex network.
{"title":"UE-to-UE Interference Measurement in Full Duplex Cellular Networks","authors":"Huan Wu, Eddy Hum, Hoda ShahMohammadian","doi":"10.1109/PIMRCW.2019.8880845","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880845","url":null,"abstract":"With significant progress of full duplex technology, next generation wireless communication systems are moving toward application of full duplex enabled networks. The main challenges for the deployment of such networks is handling the additional interferences between nodes and devices. In an early deployment scenario where the base stations operate in full duplex mode while the user equipment remain in the half duplex mode, the mutual interference between the paired UEs of full duplex scheduling is a critical issue and needs to be well addressed in order to capitalize on the gain of a full duplex system. In this paper, we present design principles of a probing signal SUIM and propose a practical and reliable solution for UE-to-UE interference measurement in a full duplex network.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"1134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129794784","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 : 2019-09-01DOI: 10.1109/PIMRCW.2019.8880824
Zafer Caliskan, R. Sokullu
In this paper, a drone based system model and prototype is presented which allows mobile phone users to make Voice over Wi-Fi calls, a.k.a. VoWiFi, while the cellular system is not available or the cellular network signal level is under a pre-defined threshold to meet the quality of service for an IP call. The drone based system consists of a drone equipped with a smart phone main board which establishes a Wi-Fi hotspot network and the user equipment, smartphone capable of making a voice over Wi-Fi calls. The system performance is evaluated based on two major parameters: the Perceptual Evaluation of Speech Quality (PESQ) scoring, and the Received Signal Strength Indicator (RSSI). The relationship between these two important parameters is investigated in real life cellular networks under various conditions.
本文提出了一种基于无人机的系统模型和原型，它允许移动电话用户在蜂窝系统不可用或蜂窝网络信号水平低于预定义阈值的情况下进行Voice over Wi-Fi呼叫，即VoWiFi，以满足IP呼叫的服务质量。基于无人机的系统由配备智能手机主板的无人机组成，该主板可以建立Wi-Fi热点网络，用户设备是能够通过Wi-Fi通话进行语音的智能手机。系统性能基于两个主要参数进行评估:语音质量感知评估(PESQ)评分和接收信号强度指标(RSSI)。在实际的蜂窝网络中，研究了这两个重要参数在各种条件下的关系。
{"title":"Drone Based Hotspot Network System Design","authors":"Zafer Caliskan, R. Sokullu","doi":"10.1109/PIMRCW.2019.8880824","DOIUrl":"https://doi.org/10.1109/PIMRCW.2019.8880824","url":null,"abstract":"In this paper, a drone based system model and prototype is presented which allows mobile phone users to make Voice over Wi-Fi calls, a.k.a. VoWiFi, while the cellular system is not available or the cellular network signal level is under a pre-defined threshold to meet the quality of service for an IP call. The drone based system consists of a drone equipped with a smart phone main board which establishes a Wi-Fi hotspot network and the user equipment, smartphone capable of making a voice over Wi-Fi calls. The system performance is evaluated based on two major parameters: the Perceptual Evaluation of Speech Quality (PESQ) scoring, and the Received Signal Strength Indicator (RSSI). The relationship between these two important parameters is investigated in real life cellular networks under various conditions.","PeriodicalId":158659,"journal":{"name":"2019 IEEE 30th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC Workshops)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132799364","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：