2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)最新文献

筛选
英文 中文
V2V Test Scenario-Study on Intersection Collision Warning 交叉口碰撞预警V2V测试场景研究
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448757
Yaqi Xu, Yuming Ge, Da Wei, Rundong Yu, Jian Wang, Zhihan Yao
{"title":"V2V Test Scenario-Study on Intersection Collision Warning","authors":"Yaqi Xu, Yuming Ge, Da Wei, Rundong Yu, Jian Wang, Zhihan Yao","doi":"10.1109/VTC2021-Spring51267.2021.9448757","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448757","url":null,"abstract":"The complex traffic environment of the intersection region makes traffic accidents occur frequently in this section. Intelligent network vehicles can give early warning of possible dangers through communication between vehicles and other traffic participants, so as to reduce the occurrence of traffic accidents. At present, many automobile enterprises are studying the landing application of vehicle to everything (V2X). This paper focuses on the application requirements of intersection collision warning (ICW) to V2X. Testing is an integral part of vehicle internet and can ensure safe and effective use of vehicle internet.In this paper, we describe in detail the testing process and results of communications performance of vehicle-to-vehicle (V2V) at an obstructed intersection in a closed test field where there are a lot of cars as a background. In addition, we have proposed a message forwarding mechanism based on vehicle to vehicle to infrastructure to vehicle (V2I2V), and the test results show that V2I2V performs better than V2V at an intersection with obstacles.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122506711","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}
引用次数: 1
On the Design of Quantization Functions for Uplink Massive MIMO with Low-Resolution ADCs 基于低分辨率adc的上行海量MIMO量化功能设计
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448919
Lifu Liu, Songyan Xue, Yi Ma, N. Yi, R. Tafazolli
{"title":"On the Design of Quantization Functions for Uplink Massive MIMO with Low-Resolution ADCs","authors":"Lifu Liu, Songyan Xue, Yi Ma, N. Yi, R. Tafazolli","doi":"10.1109/VTC2021-Spring51267.2021.9448919","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448919","url":null,"abstract":"Quantization is the characterization of analogue-to-digital converters (ADC) in massive MIMO systems. The design of quantization function or quantization thresholds is found to relate to quantization step, which is the factor that adapts with the changing of transmit power and noise variance. With the objective of utilizing low-resolution ADC is reducing the cost of massive MIMO, we propose an idea as if it is necessary to have adaptive-threshold quantization function. It is found that when maximum-likelihood (ML) is employed as the detection method, having quantization thresholds fixed for low-resolution ADCs will not cause significant performance loss. Moreover, such fixed-threshold quantization function does not require any information of signal power which can reduce the hardware cost of ADCs. Simulations have been carried out in this paper to make comparisons between fixed-threshold and adaptive-threshold quantization regarding various factors.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121887959","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}
引用次数: 3
An Efficient ToA Estimation Technique Based on Phase Correction for 5G mMTC system 基于相位校正的5G mMTC系统ToA估计方法
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448888
Xining Yang, Jinhong Yuan, Yiqing Zhou, Jinglin Shi
{"title":"An Efficient ToA Estimation Technique Based on Phase Correction for 5G mMTC system","authors":"Xining Yang, Jinhong Yuan, Yiqing Zhou, Jinglin Shi","doi":"10.1109/VTC2021-Spring51267.2021.9448888","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448888","url":null,"abstract":"In 5G mMTC system, massive user equipment (UE) access network simultaneously by contending a common RACH resource. It is thus of significant importance for network to estimate the time-of-arrival (ToA) of each UE efficiently based on preamble allocated for Physical Random Access Channel(PRACH) so that UE can achieve uplink synchronization with network reliably. In this paper, we focus on improving the accuracy and performance of ToA estimation. Considering the phase ambiguity problem due to varied propagation delay defined as ToA during detection of preamble signals generated by UE, we propose a ToA estimation technique to compensate phase transition with a set of pre-determined phase corrector vectors(PCV) associated with all possible ToA values. Furthermore, we optimize PCVs by build a reduced and essential PCV candidate as a smaller search space for more efficient phase recover and ToA estimation. Simulation results show that the performance of proposed method and its variants can fulfill the requirements of 3GPP standard with lower computational complexity.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128508130","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}
引用次数: 0
Video Quality and Latency for UAV Teleoperation over LTE: A Study with ns3 基于ns3的无人机LTE远程操作视频质量与时延研究
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448676
Antonia Stornig, Aymen Fakhreddine, H. Hellwagner, P. Popovski, C. Bettstetter
{"title":"Video Quality and Latency for UAV Teleoperation over LTE: A Study with ns3","authors":"Antonia Stornig, Aymen Fakhreddine, H. Hellwagner, P. Popovski, C. Bettstetter","doi":"10.1109/VTC2021-Spring51267.2021.9448676","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448676","url":null,"abstract":"Teleoperation of an unmanned aerial vehicle (UAV) is a challenging mobile application with real-time control from a first-person view. It poses stringent latency requirements for both video and control traffic. This paper studies the video quality and latencies for UAV teleoperation over LTE using ns3 simulations. A key ingredient is the latency budget model. We observe that the latency of the video is higher and more sensitive to mobility than that of the control traffic. The latency is influenced by the traffic variation caused by the variable bit rate of the streaming application. High mobility tends to increase latency and lead to more outliers, being problematic in real-time control.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129668051","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}
引用次数: 9
WiFi CSI-Based Device-free Multi-room Presence Detection using Conditional Recurrent Network 基于WiFi csi的条件循环网络无设备多房间存在检测
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448848
Fang-Yu Chu, Chun-Jie Chiu, An-Hung Hsiao, Kai-Ten Feng, Po-Hsuan Tseng
{"title":"WiFi CSI-Based Device-free Multi-room Presence Detection using Conditional Recurrent Network","authors":"Fang-Yu Chu, Chun-Jie Chiu, An-Hung Hsiao, Kai-Ten Feng, Po-Hsuan Tseng","doi":"10.1109/VTC2021-Spring51267.2021.9448848","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448848","url":null,"abstract":"Human presence detection via camera-based monitoring systems has been well-adopted in various applications including smart homes, factories, and hospitals. However, its privacy concerns have been raised in many occasions such as daycare centers and homes with elderly living alone. In recent years, literatures adopting wireless signals were proposed to resolve privacy issues for presence detection; nevertheless, existing works can only be applied in a single room scenario. In this paper, we are the first work to propose a device-free multi-room human presence detection system based on efficient star network topology. Our proposed conditional recurrent architecture-based multi-room presence detection (C-MuRP) system extracts both spatial and temporal features from the Wi-Fi channel state information (CSI). Associated with a voting scheme, the proposed novel deep-learning architecture classifies the states of multi-room with the condition on current waveform to emphasize present feature states. Real-time experimental results showed that our proposed C-MuRP system can achieve higher accuracy for multi-room presence detection compared to existing methods.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129791225","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}
引用次数: 14
Decentralized Planning-Assisted Deep Reinforcement Learning for Collision and Obstacle Avoidance in UAV Networks 分布式规划辅助深度强化学习在无人机网络中的碰撞与避障
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448710
Juntong Lin, Hsiao-Ting Chiu, Rung-Hung Gau
{"title":"Decentralized Planning-Assisted Deep Reinforcement Learning for Collision and Obstacle Avoidance in UAV Networks","authors":"Juntong Lin, Hsiao-Ting Chiu, Rung-Hung Gau","doi":"10.1109/VTC2021-Spring51267.2021.9448710","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448710","url":null,"abstract":"In this paper, we propose using a decentralized planning-assisted approach of deep reinforcement learning for collision and obstacle avoidance in UAV networks. We focus on a UAV network where there are multiple UAVs and multiple static obstacles. To avoid hitting obstacles without severely deviating from the ideal UAV trajectories, we propose merging adjacent obstacles based on convex hulls and design a novel trajectory planning algorithm. For UAVs to efficiently avoid collisions in a distributed manner, we propose using a decentralized multi-agent deep reinforcement learning approach based on policy gradients. In addition, we propose using a priority-based algorithm for avoiding collisions without reducing the speeds of UAVs too much. Simulation results show that the proposed decentralized planning-assisted deep reinforcement learning approach outperforms a number of baseline approaches in terms of the probability that all UAVs successfully reach their goals within the deadline.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124208898","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}
引用次数: 3
The Implementation of a SIP-Based Service Platform for 5G IoT Applications 基于sip的5G物联网应用业务平台的实现
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448772
I-Fen Yang, Yi-Chun Lin, Shun-Ren Yang, P. Lin
{"title":"The Implementation of a SIP-Based Service Platform for 5G IoT Applications","authors":"I-Fen Yang, Yi-Chun Lin, Shun-Ren Yang, P. Lin","doi":"10.1109/VTC2021-Spring51267.2021.9448772","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448772","url":null,"abstract":"Internet of things (IoT) technologies have been applied to realize various applications/services, ranging from massive, broadband, critical to industrial automation IoT applications. Recently, several IoT service platforms have been proposed to facilitate IoT application deployment, such as OpenMTC and IoTtalk. These platforms typically utilize the lightweight MQTT or CoAP application protocol to communicate with their served devices, both optimized for massive IoT applications within constrained networks. Unfortunately, these protocols are not applicable to those more advanced IoT applications, which demand high data rate and low latency. To provide a full range of supports for different IoT application scenarios, Session Initiation Protocol (SIP) can be a better candidate, which, besides instant messaging, can also handle the long session semantic and the publish-subscribe semantic. In the literature, different SIP semantics have been utilized to implement different IoT applications/systems. However, to the best of our knowledge, there exists no generic SIP-based IoT service platform that integrates relevant capabilities for developers to flexibly develop/deploy heterogeneous IoT applications, demanding different quality of service. This paper implements a SIP-based IoT service platform, iSIPtalk, which enables rapid development of more advanced IoT applications. To justify the applicability of iSIPtalk, we deploy a real testbed and implement a vehicular service within our proposed iSIPtalk. Finally, via delay measurements using the real testbed and the vehicular service, we demonstrate the performance of our iSIPtalk.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124239331","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}
引用次数: 3
A Two-Timescale Resource Allocation Scheme in Vehicular Network Slicing 车辆网络切片中的双时间尺度资源分配方案
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448852
Yaping Cui, Xinyun Huang, P. He, D. Wu, Ruyang Wang
{"title":"A Two-Timescale Resource Allocation Scheme in Vehicular Network Slicing","authors":"Yaping Cui, Xinyun Huang, P. He, D. Wu, Ruyang Wang","doi":"10.1109/VTC2021-Spring51267.2021.9448852","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448852","url":null,"abstract":"Network slicing can support the diverse use cases with heterogeneous requirements, and has been considered as one of the key roles in future networks. However, as the dynamic traffic demands and the mobility in vehicular networks, how to perform RAN slicing efficiently to provide stable quality of service (QoS) for connected vehicles is still a challenge. In order to meet the diversified service request of vehicles in such a dynamic vehicular environment, in this paper, we propose a two-timescale radio resource allocation scheme, namely, LSTM-DDPG, to provide stable service for vehicles. Specifically, for the long-term dynamic characteristics of service request from vehicles, we use long short-term memory (LSTM) to follow the tracks, such that the dedicated resource allocation is executed in a long timescale by using historical data. On the other hand, for the impacts of channel changes caused by high-speed movement in a short period, a deep reinforcement learning (DRL) algorithm, i.e., deep deterministic policy gradient (DDPG), is leveraged to adjust the allocated resources. We prove the effectiveness of the proposed LSTM-DDPG with simulation results, the cumulative probability that the slice supplies a stable performance to the served vehicle within the resource scheduling interval can reach more than 90%. Compared with the conventional deep Q-networks (DQN), the average cumulative probability has increased by 27.8%.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116299840","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}
引用次数: 3
Travel Time Prediction and Route Performance Analysis in BRTS based on Sparse GPS Data 基于GPS稀疏数据的BRTS行程时间预测与路由性能分析
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448832
A. Kakarla, V. K. Munagala, T. Ishizaka, A. Fukuda, S. Jana
{"title":"Travel Time Prediction and Route Performance Analysis in BRTS based on Sparse GPS Data","authors":"A. Kakarla, V. K. Munagala, T. Ishizaka, A. Fukuda, S. Jana","doi":"10.1109/VTC2021-Spring51267.2021.9448832","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448832","url":null,"abstract":"A Bus Rapid Transit System (BRTS) with earmarked lanes potentially provides efficient public transportation, and helps in controlling urban traffic congestion. While travel time prediction (TTP) is essential in a BRTS, existing algorithms generally assume GPS logs available at short uniform intervals. However, those are rarely evaluated on BRTS in emerging economies, where logged GPS data could be available at sparse nonuniform intervals. To fill the gap, we study the efficacy of certain well known ML models, namely, Random Forests (RF), Light Gradient Boosting (LGB), and Extreme Gradient Boosting (XGBoost, XGB) in utilizing historical data. Performance of those ensemble learning methods is compared with that of a conventional travel time prediction (CTTP) method, which uses historical averaging. It was found that XGB was superior to other methods at hand, and the prediction error by approximately 60% compared to the CTTP method. Alongside improving the experience of commuters, the proposed XGB-based TTP method also improves the estimation of intersection crossing time (ICT), which potentially leads to efficient traffic policy making.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116343695","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}
引用次数: 1
Design aspects on physical layer structure for 5G V2X and related issues 5G V2X物理层结构设计及相关问题
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring) Pub Date : 2021-04-01 DOI: 10.1109/VTC2021-Spring51267.2021.9448874
Mengmeng Liu, Haoyu Deng, Zhenting Li, Yongdong Zhu
{"title":"Design aspects on physical layer structure for 5G V2X and related issues","authors":"Mengmeng Liu, Haoyu Deng, Zhenting Li, Yongdong Zhu","doi":"10.1109/VTC2021-Spring51267.2021.9448874","DOIUrl":"https://doi.org/10.1109/VTC2021-Spring51267.2021.9448874","url":null,"abstract":"The 3rd Generation Partnership Project (3GPP) is currently studying the support of advanced Vehicle-to-Everything (V2X) services based on 5G New Radio (NR). The standardization work in Release 16 has been completed in June 2020. In order to achieve the high reliability and low latency requirements of the advanced V2X services, substantial changes are required to extend the NR framework to sidelink. This paper elaborates the state-of-art design aspects on physical layer structure for 5G V2X in Release 16. Some technical issues and future enhancements are also presented.","PeriodicalId":194840,"journal":{"name":"2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114704620","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}
引用次数: 0
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:604180095
Book学术官方微信