Pub Date : 2008-12-08DOI: 10.1109/PIMRC.2008.4699736
I. Martín-Escalona, F. Barceló
This paper presents a positioning algorithm to improve the performance of location systems based on two-way TOA techniques. This algorithm, which we call passive-TDOA, consists of computing the time-difference-of-arrival (TDOA) measurements from the TOA messages that some terminals generate in the positioning process. Passive-TDOA offers accurate results under optimum geometry. This work goes a step further and evaluates the accuracy of the algorithm in scenarios with adverse geometry. Accordingly, scenarios with access points in line and non-line of sight are studied through simulation and compared with the accuracy achieved by means of regular TOA.
{"title":"Impact of geometry on the accuracy of the passive-TDOA algorithm","authors":"I. Martín-Escalona, F. Barceló","doi":"10.1109/PIMRC.2008.4699736","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699736","url":null,"abstract":"This paper presents a positioning algorithm to improve the performance of location systems based on two-way TOA techniques. This algorithm, which we call passive-TDOA, consists of computing the time-difference-of-arrival (TDOA) measurements from the TOA messages that some terminals generate in the positioning process. Passive-TDOA offers accurate results under optimum geometry. This work goes a step further and evaluates the accuracy of the algorithm in scenarios with adverse geometry. Accordingly, scenarios with access points in line and non-line of sight are studied through simulation and compared with the accuracy achieved by means of regular TOA.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"2008 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125610367","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699448
R. Liu, Z. Rosberg, I. Collings, Carol Wilson, A. Dong, S. Jha
We derive two new energy efficient reliable data transport protocols for overcoming the negative impact of asymmetric radio links in wireless sensor networks. The energy efficiency of these algorithms is explicitly derived using our theoretical model, and validated by results obtained from simulations and field trials. The analytical, simulation and field trials demonstrate that our proposed protocols perform well in networks with asymmetric links and can save energy of up to 27% compared to conventional ARQ schemes.
{"title":"Overcoming radio link asymmetry in wireless sensor networks","authors":"R. Liu, Z. Rosberg, I. Collings, Carol Wilson, A. Dong, S. Jha","doi":"10.1109/PIMRC.2008.4699448","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699448","url":null,"abstract":"We derive two new energy efficient reliable data transport protocols for overcoming the negative impact of asymmetric radio links in wireless sensor networks. The energy efficiency of these algorithms is explicitly derived using our theoretical model, and validated by results obtained from simulations and field trials. The analytical, simulation and field trials demonstrate that our proposed protocols perform well in networks with asymmetric links and can save energy of up to 27% compared to conventional ARQ schemes.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121840239","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699783
S. Valaee
In this paper, we introduce distributed traffic regulation for wireless local area networks (WLANs) operating in ad hoc mode. We use the concept of service curve to determine the minimum guaranteed service given to a backlogged connection. In a WLAN, the service curve depends on the number of active nodes, their traffic load in active periods, and the back-off procedure used for contention resolution. We will show that service curve can be used for distributed traffic regulation. We use some of the data packets, denoted as the probing packets, to estimate the service curve. The call is accepted if the service curve is higher than a preselected threshold, called the universal lower bound. The universal lower bound is independent of the number of nodes and traffic fluctuation and acts as a worst-case reference point for the network performance.
{"title":"Bandwidth estimation and distributed traffic regulation in wireless local area networks","authors":"S. Valaee","doi":"10.1109/PIMRC.2008.4699783","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699783","url":null,"abstract":"In this paper, we introduce distributed traffic regulation for wireless local area networks (WLANs) operating in ad hoc mode. We use the concept of service curve to determine the minimum guaranteed service given to a backlogged connection. In a WLAN, the service curve depends on the number of active nodes, their traffic load in active periods, and the back-off procedure used for contention resolution. We will show that service curve can be used for distributed traffic regulation. We use some of the data packets, denoted as the probing packets, to estimate the service curve. The call is accepted if the service curve is higher than a preselected threshold, called the universal lower bound. The universal lower bound is independent of the number of nodes and traffic fluctuation and acts as a worst-case reference point for the network performance.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127967378","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699516
Z. Ding, K. Leung
In this paper, we study the impact of cooperative transmission on the routing decision for wireless ad-hoc networks. The influence of cooperative transmission to the wireless link cost is first studied at the physical layer. Then the problem of routing optimization is investigated to understand the effects of improved link cost on the routing decision, where the closed-form solution of the optimization problem is developed and later used as a quantitative criterion of the route selection. Our developed analytical and simulation results show that the criteria using cooperative transmission typically yield more efficient routes compared with the non-cooperative schemes.
{"title":"Cross-layer routing optimization for wireless networks with cooperative diversity","authors":"Z. Ding, K. Leung","doi":"10.1109/PIMRC.2008.4699516","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699516","url":null,"abstract":"In this paper, we study the impact of cooperative transmission on the routing decision for wireless ad-hoc networks. The influence of cooperative transmission to the wireless link cost is first studied at the physical layer. Then the problem of routing optimization is investigated to understand the effects of improved link cost on the routing decision, where the closed-form solution of the optimization problem is developed and later used as a quantitative criterion of the route selection. Our developed analytical and simulation results show that the criteria using cooperative transmission typically yield more efficient routes compared with the non-cooperative schemes.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132311158","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699875
C. Park, Y. Guo, L. Ong, M. Zhou
The 60-GHz band wireless link using microwave photonics technologies for gigabit wireless applications is presented. The microwave photonic frequency upconverter utilizing the fiber-optic wavelength conversion is adopted as a method for the wireless downlink and the seamless integration of wired and wireless networks. The proposed system shows the spurious-free dynamic range of 81.2 dBmiddotHz2/3. The optically generated carrier at 62.75 GHz has the phase noise of -73.8 dBc/Hz at a 10-kHz offset. The system performance is optimized by controlling optical parameters for error-free transmission. Error-free transmission of the 1.25-Gb/s data carried in 62.75 GHz is achieved for 20-km fiber transmission between the central station and the remote base stations (BSs) including 1-m aerial transmission between the BSs and the customer unit using horn antennas.
{"title":"Microwave photonic 60-GHz wireless link for gigabit connectivity","authors":"C. Park, Y. Guo, L. Ong, M. Zhou","doi":"10.1109/PIMRC.2008.4699875","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699875","url":null,"abstract":"The 60-GHz band wireless link using microwave photonics technologies for gigabit wireless applications is presented. The microwave photonic frequency upconverter utilizing the fiber-optic wavelength conversion is adopted as a method for the wireless downlink and the seamless integration of wired and wireless networks. The proposed system shows the spurious-free dynamic range of 81.2 dBmiddotHz2/3. The optically generated carrier at 62.75 GHz has the phase noise of -73.8 dBc/Hz at a 10-kHz offset. The system performance is optimized by controlling optical parameters for error-free transmission. Error-free transmission of the 1.25-Gb/s data carried in 62.75 GHz is achieved for 20-km fiber transmission between the central station and the remote base stations (BSs) including 1-m aerial transmission between the BSs and the customer unit using horn antennas.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132458840","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699859
A. Chaudhry, J. Khan
Multimedia broadcast and multicast service (MBMS) specification was introduced in the release 6 of the 3GPP standard to deliver multimedia content to a large group of users in the UMTS network. With the MBMS system generally the same content is transmitted to multiple users in a unidirectional fashion, typically by multiple base stations to improve the coverage over a large geographical area. From the radio network point of view the standard supports the point-to-point (p-t-p) and the point-to-multipoint (p-t-m) transmission modes. In this paper we propose a group based p-t-m MBMS algorithm utilising the scalable video coding techniques to improve overall QoS of multimedia services. The group based MBMS algorithm has been proposed to support moderate to high date rate multicasting services over the HSDPA link. The proposed algorithm has been simulated using an OPNET simulation model. Initial results show that the proposed algorithm could offer higher data and improved QoS for MBMS users.
{"title":"A group based point-to-multipoint MBMS algorithm over the HSDPA network","authors":"A. Chaudhry, J. Khan","doi":"10.1109/PIMRC.2008.4699859","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699859","url":null,"abstract":"Multimedia broadcast and multicast service (MBMS) specification was introduced in the release 6 of the 3GPP standard to deliver multimedia content to a large group of users in the UMTS network. With the MBMS system generally the same content is transmitted to multiple users in a unidirectional fashion, typically by multiple base stations to improve the coverage over a large geographical area. From the radio network point of view the standard supports the point-to-point (p-t-p) and the point-to-multipoint (p-t-m) transmission modes. In this paper we propose a group based p-t-m MBMS algorithm utilising the scalable video coding techniques to improve overall QoS of multimedia services. The group based MBMS algorithm has been proposed to support moderate to high date rate multicasting services over the HSDPA link. The proposed algorithm has been simulated using an OPNET simulation model. Initial results show that the proposed algorithm could offer higher data and improved QoS for MBMS users.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130247463","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699797
M. Rasti, A. Sharafat
In the opportunistic power control algorithm (OPC), designed in each user tries to keep the product of its transmit power and its experienced effective interference to a constant, called the target signal-interference product (SIP). This increases the transmit power when the channel is good and reduces it when the channel is poor (opportunism). It has been shown that the OPC always converges to a fixed point irrespective of whether the power is constrained (where there is no upper bound on transmit power) or unconstrained (where an upper bound on transmit power is taken into account). It has also been shown via simulation that the throughput achieved by the unconstrained OPC is significant (as compared to other existing distributed schemes), and is an increasing function of the target-SIP set by users, in the sense that a higher target-SIP results in a higher throughput. In this paper, we show that in contrast to the unconstrained OPC, when the constrained OPC is applied, not only the throughput is not necessarily increased as the target-SIPs increase, but it may even decrease if some users set their target-SIPs at high values. Furthermore, we propose a heuristic solution to determine the target-SIPs by users in a distributed manner. Our simulation results show that the throughput achieved by our distributed setting of the target-SIPs very closely approaches the maximum achievable throughput by the constrained OPC, and is very close to the global optimum value.
{"title":"Constrained opportunistic power control in wireless networks","authors":"M. Rasti, A. Sharafat","doi":"10.1109/PIMRC.2008.4699797","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699797","url":null,"abstract":"In the opportunistic power control algorithm (OPC), designed in each user tries to keep the product of its transmit power and its experienced effective interference to a constant, called the target signal-interference product (SIP). This increases the transmit power when the channel is good and reduces it when the channel is poor (opportunism). It has been shown that the OPC always converges to a fixed point irrespective of whether the power is constrained (where there is no upper bound on transmit power) or unconstrained (where an upper bound on transmit power is taken into account). It has also been shown via simulation that the throughput achieved by the unconstrained OPC is significant (as compared to other existing distributed schemes), and is an increasing function of the target-SIP set by users, in the sense that a higher target-SIP results in a higher throughput. In this paper, we show that in contrast to the unconstrained OPC, when the constrained OPC is applied, not only the throughput is not necessarily increased as the target-SIPs increase, but it may even decrease if some users set their target-SIPs at high values. Furthermore, we propose a heuristic solution to determine the target-SIPs by users in a distributed manner. Our simulation results show that the throughput achieved by our distributed setting of the target-SIPs very closely approaches the maximum achievable throughput by the constrained OPC, and is very close to the global optimum value.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133861753","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699502
Thierry Peyre, R. E. Azouzi, T. Chahed
In this paper, we propose and analyse a new scheme to handle ranging requests in IEEE 802.16e networks based on differentiated backoff parameters and a novel hierarchical code partitioning principle. Our analysis is of the form of a fixed-point equation which characterizes the system operating points and which allows us to compute the attempt rate of each QoS class as well as the distribution of the number of ranging bandwidth requests received successfully by the base station as well as their average delay. Both analysis and simulation confirm that our scheme yields high throughput and low collision probability for real-time connections without altering the collision probability for non-real-time connections.
{"title":"QoS differentiation for initial and bandwidth request ranging in IEEE802.16","authors":"Thierry Peyre, R. E. Azouzi, T. Chahed","doi":"10.1109/PIMRC.2008.4699502","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699502","url":null,"abstract":"In this paper, we propose and analyse a new scheme to handle ranging requests in IEEE 802.16e networks based on differentiated backoff parameters and a novel hierarchical code partitioning principle. Our analysis is of the form of a fixed-point equation which characterizes the system operating points and which allows us to compute the attempt rate of each QoS class as well as the distribution of the number of ranging bandwidth requests received successfully by the base station as well as their average delay. Both analysis and simulation confirm that our scheme yields high throughput and low collision probability for real-time connections without altering the collision probability for non-real-time connections.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133898814","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699507
Gillian Huang, A. Nix, S. Armour
SC-FDMA (Single-Carrier Frequency Division Multiple Access) is employed in the 3GPP LTE (Long-Term Evolution) standard as the uplink transmission scheme. The SC-FDMA signal has a low PAPR. This makes it well-suited to power efficient transmission at the mobile terminal. Although it is a common assumption to use frequency-domain linear equalization in SC-FDMA, a decision feedback equalizer (DFE) composed of a frequency-domain feedforward filter and a time-domain feedback filter can provide enhanced performance. Even when error propagation is taken into account, results show that a DFE still offers a significant performance gain over the conventional LE for uncoded SC-FDMA. This paper demonstrates that SC-FDMA with DFE is capable of increasing the throughput in a power limited channel by up to 41% compared to LE. Alternatively, for a given peak transmit power, the use of a DFE can achieve a 14% coverage extension in NLOS and 19% in LOS.
{"title":"Decision feedback equalization in SC-FDMA","authors":"Gillian Huang, A. Nix, S. Armour","doi":"10.1109/PIMRC.2008.4699507","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699507","url":null,"abstract":"SC-FDMA (Single-Carrier Frequency Division Multiple Access) is employed in the 3GPP LTE (Long-Term Evolution) standard as the uplink transmission scheme. The SC-FDMA signal has a low PAPR. This makes it well-suited to power efficient transmission at the mobile terminal. Although it is a common assumption to use frequency-domain linear equalization in SC-FDMA, a decision feedback equalizer (DFE) composed of a frequency-domain feedforward filter and a time-domain feedback filter can provide enhanced performance. Even when error propagation is taken into account, results show that a DFE still offers a significant performance gain over the conventional LE for uncoded SC-FDMA. This paper demonstrates that SC-FDMA with DFE is capable of increasing the throughput in a power limited channel by up to 41% compared to LE. Alternatively, for a given peak transmit power, the use of a DFE can achieve a 14% coverage extension in NLOS and 19% in LOS.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130788372","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 : 2008-12-08DOI: 10.1109/PIMRC.2008.4699795
G. Gódor, Marton Cserbak
As RFID technology is becoming ubiquitous, the security of these systems gets - as it should - much attention. Its fields of usage include personal identification, supply-chain management systems, and many more. Many kinds of RFID tags are available on the market which differ both in storage, and computational capacity. Since by standard IT means all the tags have small capacities, the security mechanisms which are in use in computer networks are not suitable. For expensive tags with relatively large computational capacities many secure communication protocols were developed, for cheap low-end tags, only a few lightweight protocols exist. In this paper we introduce our solution, which is based on the least computation demanding operator, the exclusive or function. By introducing two tags instead of one in the RFID system, our scheme provides security solutions which are comparable with those provided by the lightweight protocols. In the meantime, our scheme does not demand any computational steps to be made by the tag.
{"title":"A lightweight security scheme in RFID enabled E-commerce environments","authors":"G. Gódor, Marton Cserbak","doi":"10.1109/PIMRC.2008.4699795","DOIUrl":"https://doi.org/10.1109/PIMRC.2008.4699795","url":null,"abstract":"As RFID technology is becoming ubiquitous, the security of these systems gets - as it should - much attention. Its fields of usage include personal identification, supply-chain management systems, and many more. Many kinds of RFID tags are available on the market which differ both in storage, and computational capacity. Since by standard IT means all the tags have small capacities, the security mechanisms which are in use in computer networks are not suitable. For expensive tags with relatively large computational capacities many secure communication protocols were developed, for cheap low-end tags, only a few lightweight protocols exist. In this paper we introduce our solution, which is based on the least computation demanding operator, the exclusive or function. By introducing two tags instead of one in the RFID system, our scheme provides security solutions which are comparable with those provided by the lightweight protocols. In the meantime, our scheme does not demand any computational steps to be made by the tag.","PeriodicalId":125554,"journal":{"name":"2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130737009","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：