Pub Date : 2001-11-25DOI: 10.1109/GLOCOM.2001.965955
Kai Liu, Jiandong Li, A. Fukuda
This paper presents a new multiple access control (MAC) protocol called adaptive acquisition collision avoidance multiple access with common-transmission code assignment (AACA-CT) for multihop ad hoc wireless networks. Multiple channels are employed in this scheme. One channel is used as the common channel for mobile users (or nodes) contending to reserve traffic channels by means of request-to-send and clear-to-send (RTS/CTS) dialogue. Other channels are used as traffic channels to transmit traffic packets without collision. With this protocol, resource reservation is flexibly and effectively made on multiple frequency bands, frequency-hopping (FH) codes or direct-sequence spread-spectrum (DSSS) codes by half-duplex radios without any help of powerful base stations (BS) or central controllers and wired backbone networks in an asynchronous fashion. The protocol can solve hidden and exposed terminal problems perfectly as is validated through analysis and numerical results. A comparison among the proposed protocol, IEEE 802.11 MAC protocols and the slotted ALOHA protocol shows that the proposed reservation-based approach has advantages over other protocols.
{"title":"Adaptive acquisition collision avoidance multiple access for multihop ad hoc wireless networks","authors":"Kai Liu, Jiandong Li, A. Fukuda","doi":"10.1109/GLOCOM.2001.965955","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965955","url":null,"abstract":"This paper presents a new multiple access control (MAC) protocol called adaptive acquisition collision avoidance multiple access with common-transmission code assignment (AACA-CT) for multihop ad hoc wireless networks. Multiple channels are employed in this scheme. One channel is used as the common channel for mobile users (or nodes) contending to reserve traffic channels by means of request-to-send and clear-to-send (RTS/CTS) dialogue. Other channels are used as traffic channels to transmit traffic packets without collision. With this protocol, resource reservation is flexibly and effectively made on multiple frequency bands, frequency-hopping (FH) codes or direct-sequence spread-spectrum (DSSS) codes by half-duplex radios without any help of powerful base stations (BS) or central controllers and wired backbone networks in an asynchronous fashion. The protocol can solve hidden and exposed terminal problems perfectly as is validated through analysis and numerical results. A comparison among the proposed protocol, IEEE 802.11 MAC protocols and the slotted ALOHA protocol shows that the proposed reservation-based approach has advantages over other protocols.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123303738","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965177
M. Martone
While the race for a ubiquitous, reliable and cost effective wireless broadband system has generated intense competition, the fundamental problem afflicting the wireless industry is the cost of the transceiver hardware. We describe and discuss the results of some experimental outdoor field trials which demonstrate - for the first time - the hardware feasibility of fixed broadband wireless radio links with spectral efficiencies in excess of 50 bit/s/Hz in severe multipath frequency selective environments (non line-of-sight). Custom cost-effective hardware has allowed data transmission in the range 60-200 Mbit/s occupying a bandwidth of 2-4/5 MHz at MMDS frequencies (/spl sime/2.5 GHz). We also introduce a new modeling methodology inspired by basic theoretical physics which gives a different and practical perspective to the spatio-temporal transmission problem. We exploit the idea that extra-dimensionality can be created by properly sampling the wavefield space created by multipath propagation. Previously reported hardware experiments using the same concept have addressed the simpler problem of indoor communications in a 30 kHz cellular channel. The developed technology has the potential of making practical and cost effective the deployment of high capacity microwave data communications equipment for point to point and point to multipoint systems.
{"title":"An experimental hardware prototype for fixed wireless broadband access at 60-400 Mbit/sec in 4.6 MHz","authors":"M. Martone","doi":"10.1109/GLOCOM.2001.965177","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965177","url":null,"abstract":"While the race for a ubiquitous, reliable and cost effective wireless broadband system has generated intense competition, the fundamental problem afflicting the wireless industry is the cost of the transceiver hardware. We describe and discuss the results of some experimental outdoor field trials which demonstrate - for the first time - the hardware feasibility of fixed broadband wireless radio links with spectral efficiencies in excess of 50 bit/s/Hz in severe multipath frequency selective environments (non line-of-sight). Custom cost-effective hardware has allowed data transmission in the range 60-200 Mbit/s occupying a bandwidth of 2-4/5 MHz at MMDS frequencies (/spl sime/2.5 GHz). We also introduce a new modeling methodology inspired by basic theoretical physics which gives a different and practical perspective to the spatio-temporal transmission problem. We exploit the idea that extra-dimensionality can be created by properly sampling the wavefield space created by multipath propagation. Previously reported hardware experiments using the same concept have addressed the simpler problem of indoor communications in a 30 kHz cellular channel. The developed technology has the potential of making practical and cost effective the deployment of high capacity microwave data communications equipment for point to point and point to multipoint systems.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123754689","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965987
H. Arslan, Jung-Fu Cheng, K. Balachandran
EDGE has enabled the GSM network to offer third generation services as part of the UMTS core network. This is due to the introduction of 8PSK modulation and the recent specification of interfaces from the GERAN to the UMTS core network. This paper studies further improvements to the spectral efficiency and capacity of EDGE through the use of more sophisticated adaptive modulation schemes based on QAM, and the use of novel turbo coding schemes. Furthermore, this work considers a novel transmit diversity scheme adapted for use in dispersive channels. We provide performance results for the enhanced system showing tremendous gains. We also use theoretical predictions of outage analysis to predict the gain in performance obtained by the use of higher order modulations and transmit diversity. The gains from theoretical predictions match our simulations almost exactly.
{"title":"Physical layer evolution for GSM/EDGE","authors":"H. Arslan, Jung-Fu Cheng, K. Balachandran","doi":"10.1109/GLOCOM.2001.965987","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965987","url":null,"abstract":"EDGE has enabled the GSM network to offer third generation services as part of the UMTS core network. This is due to the introduction of 8PSK modulation and the recent specification of interfaces from the GERAN to the UMTS core network. This paper studies further improvements to the spectral efficiency and capacity of EDGE through the use of more sophisticated adaptive modulation schemes based on QAM, and the use of novel turbo coding schemes. Furthermore, this work considers a novel transmit diversity scheme adapted for use in dispersive channels. We provide performance results for the enhanced system showing tremendous gains. We also use theoretical predictions of outage analysis to predict the gain in performance obtained by the use of higher order modulations and transmit diversity. The gains from theoretical predictions match our simulations almost exactly.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125292240","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.966223
Sakir Yucel, T. Saydam
Networked multimedia applications are sensitive to the QoS provided by the underlying communication networks. CORBA audio/video stream specification provides a programming abstraction and API for developing networked multimedia applications with QoS constraints independently of the underlying networking technology. That specification does not address how the underlying communication network would support the QoS needed by the multimedia application. As the QoS is becoming a key consideration in IP, we address the realization of the CORBA specification over IP technologies and propose a service management architecture for mapping, monitoring, managing and controlling multimedia QoS over IP technologies. We further develop the main components of this architecture. The architecture makes extensive use of document driven programming (DDP) techniques and software agents for performing QoS mechanisms. Advantages and issues with these approaches are distinguished in the paper.
{"title":"An architecture for realizing CORBA audio/video stream specification over IP technologies","authors":"Sakir Yucel, T. Saydam","doi":"10.1109/GLOCOM.2001.966223","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.966223","url":null,"abstract":"Networked multimedia applications are sensitive to the QoS provided by the underlying communication networks. CORBA audio/video stream specification provides a programming abstraction and API for developing networked multimedia applications with QoS constraints independently of the underlying networking technology. That specification does not address how the underlying communication network would support the QoS needed by the multimedia application. As the QoS is becoming a key consideration in IP, we address the realization of the CORBA specification over IP technologies and propose a service management architecture for mapping, monitoring, managing and controlling multimedia QoS over IP technologies. We further develop the main components of this architecture. The architecture makes extensive use of document driven programming (DDP) techniques and software agents for performing QoS mechanisms. Advantages and issues with these approaches are distinguished in the paper.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125334001","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.966326
M. Looi
In this paper, we propose enhancing the current "knowledge factor" user authentication systems common on the Internet by incorporating multiple factor authentication using the mobile telephone networks. We suggest that the "possession factor" and the "location factor" can significantly enhance user authentication, and demonstrate how these two factors can be added for minimal cost. A prototype system is described.
{"title":"Enhanced authentication services for Internet systems using mobile networks","authors":"M. Looi","doi":"10.1109/GLOCOM.2001.966326","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.966326","url":null,"abstract":"In this paper, we propose enhancing the current \"knowledge factor\" user authentication systems common on the Internet by incorporating multiple factor authentication using the mobile telephone networks. We suggest that the \"possession factor\" and the \"location factor\" can significantly enhance user authentication, and demonstrate how these two factors can be added for minimal cost. A prototype system is described.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125487892","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.966009
S. Sud, W. Myrick, J. S. Goldstein, M. Zoltowski
A new reduced rank multiuser detector (MUD) for DS-CDMA is presented. The algorithm is derived for the general case of an asynchronous DS-CDMA system in frequency selective multipath. The MUD solution is shown to be equivalent to a bank of parallel, single user detectors. The algorithm is implemented in reduced rank form using the correlations subtractive algorithm of the multistage Wiener filter (CSA-MWF). It is shown that the CSA-MWF implementation performs identically to the full rank solutions of MMSE MUD and meets single user, full rank performance at a substantially reduced rank for all levels of system load.
{"title":"Performance analysis of a reduced rank MMSE MUD for DS-CDMA","authors":"S. Sud, W. Myrick, J. S. Goldstein, M. Zoltowski","doi":"10.1109/GLOCOM.2001.966009","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.966009","url":null,"abstract":"A new reduced rank multiuser detector (MUD) for DS-CDMA is presented. The algorithm is derived for the general case of an asynchronous DS-CDMA system in frequency selective multipath. The MUD solution is shown to be equivalent to a bank of parallel, single user detectors. The algorithm is implemented in reduced rank form using the correlations subtractive algorithm of the multistage Wiener filter (CSA-MWF). It is shown that the CSA-MWF implementation performs identically to the full rank solutions of MMSE MUD and meets single user, full rank performance at a substantially reduced rank for all levels of system load.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126781460","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965712
S. H. Muller-Weinfurtner
Preamble schemes with periodic signal repetitions are often used for synchronization purposes in transmission over dispersive media. We describe a sandamble, being a splitted repetition preamble with reduced training overhead, and compare its frame and frequency synchronization performance in burst transmission to the performance of a conventional repetition preamble like standardized IEEE 802.11a or HiperLAN/2 wireless modems. Optimum frame position and frequency offset estimation from a sandamble structure is treated and the Cramer-Rao lower bound for frequency estimation is derived. Though the fundamental idea is independent from the specific modulation scheme, we show results for orthogonal frequency-division multiplexing (OFDM).
{"title":"Burst frame and frequency synchronization with a sandwich preamble","authors":"S. H. Muller-Weinfurtner","doi":"10.1109/GLOCOM.2001.965712","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965712","url":null,"abstract":"Preamble schemes with periodic signal repetitions are often used for synchronization purposes in transmission over dispersive media. We describe a sandamble, being a splitted repetition preamble with reduced training overhead, and compare its frame and frequency synchronization performance in burst transmission to the performance of a conventional repetition preamble like standardized IEEE 802.11a or HiperLAN/2 wireless modems. Optimum frame position and frequency offset estimation from a sandamble structure is treated and the Cramer-Rao lower bound for frequency estimation is derived. Though the fundamental idea is independent from the specific modulation scheme, we show results for orthogonal frequency-division multiplexing (OFDM).","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115037228","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.966214
Y. Won, Soohan Ahn, J. Jeon
A long-observed characteristic of empirical VBR process is its slowly decaying sample autocorrelations. In this work, we explain slowly decaying sample autocorrelations of the empirical VBR using the non-stationary model, which well reflects the stochastic characteristics of VBR process. Our model generates the synthetic sequence which has the same periodic characteristics as well as slowly decaying sample autocorrelations of the empirical VBR process. Simulation experiment results confirm that the proposed model provides satisfiably good projection on stochastic behavior of the empirical process in terms of packet loss and burstiness of packet loss. The result of our work not only contributes to providing the theoretical explanation on the observed characteristics of VBR traffic but also contributes to developing an efficient method for generating a synthetic sequence for various engineering purposes.
{"title":"Performance analysis of non-stationary model for empirical VBR process","authors":"Y. Won, Soohan Ahn, J. Jeon","doi":"10.1109/GLOCOM.2001.966214","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.966214","url":null,"abstract":"A long-observed characteristic of empirical VBR process is its slowly decaying sample autocorrelations. In this work, we explain slowly decaying sample autocorrelations of the empirical VBR using the non-stationary model, which well reflects the stochastic characteristics of VBR process. Our model generates the synthetic sequence which has the same periodic characteristics as well as slowly decaying sample autocorrelations of the empirical VBR process. Simulation experiment results confirm that the proposed model provides satisfiably good projection on stochastic behavior of the empirical process in terms of packet loss and burstiness of packet loss. The result of our work not only contributes to providing the theoretical explanation on the observed characteristics of VBR traffic but also contributes to developing an efficient method for generating a synthetic sequence for various engineering purposes.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122357133","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965835
M. Mellia, A. Nucci, A. Grosso, Emilio Leonardi, M. Marsan
In this paper we discuss the optimal design of logical topologies in wavelength-routed WDM networks supporting unicast and multicast transfer of IP datagrams. We first explain the key aspects of the problem, emphasizing the fact that in IP networks the routing algorithms are an input to the optimization problem, not an optimization target. We then provide a mixed integer linear programming formulation of the optimization problem., which however leads to unacceptably high complexity for networks of non-trivially small size. We then propose both greedy and metaheuristic approaches for the sub-optimal design of logical topologies with acceptable complexity. Finally, we derive lower bounds that allow the assessment of the performance of the proposed algorithms. Some numerical results indicate that the proposed metaheuristics largely outperform the greedy approaches, and are able to obtain very good logical topologies.
{"title":"Optimal design of logical topologies in wavelength-routed optical networks with multicast traffic","authors":"M. Mellia, A. Nucci, A. Grosso, Emilio Leonardi, M. Marsan","doi":"10.1109/GLOCOM.2001.965835","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965835","url":null,"abstract":"In this paper we discuss the optimal design of logical topologies in wavelength-routed WDM networks supporting unicast and multicast transfer of IP datagrams. We first explain the key aspects of the problem, emphasizing the fact that in IP networks the routing algorithms are an input to the optimization problem, not an optimization target. We then provide a mixed integer linear programming formulation of the optimization problem., which however leads to unacceptably high complexity for networks of non-trivially small size. We then propose both greedy and metaheuristic approaches for the sub-optimal design of logical topologies with acceptable complexity. Finally, we derive lower bounds that allow the assessment of the performance of the proposed algorithms. Some numerical results indicate that the proposed metaheuristics largely outperform the greedy approaches, and are able to obtain very good logical topologies.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122460209","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 : 2001-11-25DOI: 10.1109/GLOCOM.2001.965202
Li Cong, W. Zhuang
We investigate the non-line-of-sight (NLOS) propagation identification and correction for time difference of arrival (TDOA) based mobile user location in wireless communication systems. Based on the defined TDOA residual, an NLOS base station identification algorithm is proposed. Different choices of the reference location for the residual calculation are compared via simulation. To correct the NLOS error with a certain distribution, we propose a maximum likelihood (ML) estimator for TDOA location systems. Simulation results demonstrate that the proposed NLOS recovering algorithm performs better than that using only LOS measurements, especially when the number of available base stations is small and/or the LOS base stations have an undesirable geometric layout.
{"title":"Non-line-of-sight error mitigation in TDOA mobile location","authors":"Li Cong, W. Zhuang","doi":"10.1109/GLOCOM.2001.965202","DOIUrl":"https://doi.org/10.1109/GLOCOM.2001.965202","url":null,"abstract":"We investigate the non-line-of-sight (NLOS) propagation identification and correction for time difference of arrival (TDOA) based mobile user location in wireless communication systems. Based on the defined TDOA residual, an NLOS base station identification algorithm is proposed. Different choices of the reference location for the residual calculation are compared via simulation. To correct the NLOS error with a certain distribution, we propose a maximum likelihood (ML) estimator for TDOA location systems. Simulation results demonstrate that the proposed NLOS recovering algorithm performs better than that using only LOS measurements, especially when the number of available base stations is small and/or the LOS base stations have an undesirable geometric layout.","PeriodicalId":346622,"journal":{"name":"GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122612358","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：