Pub Date : 2000-12-17DOI: 10.1109/ICPWC.2000.905792
Manjeet Singh, I. Wassell
Continuous phase modulation (CPM) is investigated. We employ the decomposed CPM model where the model is decomposed into a continuous phase encoder (CPE) and a memoryless modulator (MM). This allows us to concentrate on the encoding aspects without interference from the modulator. By designing a convolutional channel encoder (CE), to operate over the same algebra as the CPE, the CE and the CPE can be combined and treated in a unified manner. This combination is called an extended CE, as the CPE is effectively an extension of the CE and is a convolutional encoder. In this research, a 1/2 rate CE over the ring of integers modulo 4 is combined with the CPE of a 4-ary CPM scheme whose modulation index is h=1/4. Using this trellis coded modulation design the paper explains the design of a serially concatenated channel coded system, where the inner encoder is the quaternary extended CE and the outer encoder a quaternary convolutional encoder. SOVA decoding is employed. Simulations show that a BER of 2.6/spl times/10/sup -4/ at 0.3 dB SNR is obtainable in an AWGN channel.
{"title":"SOVA decoding of concatenated convolutional encoders and CPM scheme over AWGN and fading channels","authors":"Manjeet Singh, I. Wassell","doi":"10.1109/ICPWC.2000.905792","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905792","url":null,"abstract":"Continuous phase modulation (CPM) is investigated. We employ the decomposed CPM model where the model is decomposed into a continuous phase encoder (CPE) and a memoryless modulator (MM). This allows us to concentrate on the encoding aspects without interference from the modulator. By designing a convolutional channel encoder (CE), to operate over the same algebra as the CPE, the CE and the CPE can be combined and treated in a unified manner. This combination is called an extended CE, as the CPE is effectively an extension of the CE and is a convolutional encoder. In this research, a 1/2 rate CE over the ring of integers modulo 4 is combined with the CPE of a 4-ary CPM scheme whose modulation index is h=1/4. Using this trellis coded modulation design the paper explains the design of a serially concatenated channel coded system, where the inner encoder is the quaternary extended CE and the outer encoder a quaternary convolutional encoder. SOVA decoding is employed. Simulations show that a BER of 2.6/spl times/10/sup -4/ at 0.3 dB SNR is obtainable in an AWGN channel.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"51 22","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120873832","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905921
U. Jha
In global system for mobile communication (GSM) and its evolution systems (such as general packet radio service, GPRS, and highspeed circuit switched data, HCSD), the cell related parameters are broadcast on a broadcast control channel (BCCH) to facilitate the mobile handsets in the area of coverage to acquire the frequency and timing synchronization as well as to obtain the cell specific parameters. The mobile handset (MS) in the cell needs to scan this BCCH (also known as 'beacon' or 'C/sub o/' channel) to find the strongest receive (Rx) carrier frequency based on the received signal strength. Once the Rx carrier frequency is known, the mobile handset's local oscillator (LO) is tuned to this frequency, which may be offset from the base station (BS) transmit (Tx) carrier frequency based on the specification of the local oscillator and operating environmental condition. The BS transmits periodically a frequency burst (FB) to allow the MS to establish the frequency synchronization with the BS. The characteristic of the FB is such that the received data stream exhibits a tone at 1/4 of the GSM symbol rate. The paper presents a novel approach based on a 2nd order adaptive LMS notch filter for the acquisition of this FB tone. Based on the local oscillator tolerance, the bandwidth of the notch filter is adjusted and the output power of the filter is compared with the received input power. The presence of a FB tone is declared, based on the ratio of the output to the input power of the filter. The threshold for FB detection is based on the signal-to-noise ratio (SNR), probability of detection and probability of false alarm. Once the FB tone is detected the notch filter shifts into the adaptive mode and iteratively converges to the actual FB tone frequency.
{"title":"Acquisition of frequency synchronization for GSM and its evolution systems","authors":"U. Jha","doi":"10.1109/ICPWC.2000.905921","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905921","url":null,"abstract":"In global system for mobile communication (GSM) and its evolution systems (such as general packet radio service, GPRS, and highspeed circuit switched data, HCSD), the cell related parameters are broadcast on a broadcast control channel (BCCH) to facilitate the mobile handsets in the area of coverage to acquire the frequency and timing synchronization as well as to obtain the cell specific parameters. The mobile handset (MS) in the cell needs to scan this BCCH (also known as 'beacon' or 'C/sub o/' channel) to find the strongest receive (Rx) carrier frequency based on the received signal strength. Once the Rx carrier frequency is known, the mobile handset's local oscillator (LO) is tuned to this frequency, which may be offset from the base station (BS) transmit (Tx) carrier frequency based on the specification of the local oscillator and operating environmental condition. The BS transmits periodically a frequency burst (FB) to allow the MS to establish the frequency synchronization with the BS. The characteristic of the FB is such that the received data stream exhibits a tone at 1/4 of the GSM symbol rate. The paper presents a novel approach based on a 2nd order adaptive LMS notch filter for the acquisition of this FB tone. Based on the local oscillator tolerance, the bandwidth of the notch filter is adjusted and the output power of the filter is compared with the received input power. The presence of a FB tone is declared, based on the ratio of the output to the input power of the filter. The threshold for FB detection is based on the signal-to-noise ratio (SNR), probability of detection and probability of false alarm. Once the FB tone is detected the notch filter shifts into the adaptive mode and iteratively converges to the actual FB tone frequency.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121236084","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905825
K. Subramanyam, A. K. Gogoi
A new technique for realization of two-way voice communication over a single carrier frequency as an improvement over the usual walky-talky type, simplex handsets, which are very widely used for civil as well as for military applications, is proposed. The challenge lies in providing cost-effective, full-duplex digital voice communication handsets, conserving the bandwidth at the same time.
{"title":"Full duplex voice communication handsets over single carrier frequency","authors":"K. Subramanyam, A. K. Gogoi","doi":"10.1109/ICPWC.2000.905825","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905825","url":null,"abstract":"A new technique for realization of two-way voice communication over a single carrier frequency as an improvement over the usual walky-talky type, simplex handsets, which are very widely used for civil as well as for military applications, is proposed. The challenge lies in providing cost-effective, full-duplex digital voice communication handsets, conserving the bandwidth at the same time.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125510454","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905799
Zhenhong Li, A. Mammela
An adaptive MLSE receiver based on per-survivor processing (PSP-MLSE) for the GSM/EDGE system with 8PSK modulation is presented. The initial channel impulse response is estimated by the LS algorithm with a training midamble sequence. The PSP-MLSE is in conjunction with the LMS algorithm to track the fast time-varying channel. Based on the EDGE burst structure, the second part of the data stream is tracked forwards while the first part is tracked backwards in order to improve the performance in rapidly changing channels. Computer simulations indicate that the PSP-MLSE is clearly superior to the conventional adaptive MLSE (CA-MLSE), especially, at high velocities. Moreover, the loss due to the estimation error is also presented by measuring the ideal system performance. Furthermore, the termination effect of the Viterbi algorithm is also discussed.
{"title":"Adaptive PSP-MLSE receiver for GSM/EDGE system in fast multipath fading channels","authors":"Zhenhong Li, A. Mammela","doi":"10.1109/ICPWC.2000.905799","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905799","url":null,"abstract":"An adaptive MLSE receiver based on per-survivor processing (PSP-MLSE) for the GSM/EDGE system with 8PSK modulation is presented. The initial channel impulse response is estimated by the LS algorithm with a training midamble sequence. The PSP-MLSE is in conjunction with the LMS algorithm to track the fast time-varying channel. Based on the EDGE burst structure, the second part of the data stream is tracked forwards while the first part is tracked backwards in order to improve the performance in rapidly changing channels. Computer simulations indicate that the PSP-MLSE is clearly superior to the conventional adaptive MLSE (CA-MLSE), especially, at high velocities. Moreover, the loss due to the estimation error is also presented by measuring the ideal system performance. Furthermore, the termination effect of the Viterbi algorithm is also discussed.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129309717","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905790
Hasung Kim, G. Struber
3G mobile multimedia communication systems based on W-CDMA support a flexible and adaptive transmission capability to provide packet data service as well as voice service. Mobile multimedia communication requires a coding scheme that can accommodate varying code rate requirements. RCPC (rate compatible punctured convolutional) codes are one practical solution to adaptive coding. RCPC codes use a single rate-1/n convolutional encoder/decoder pair and the transmitter and receiver only need to share a puncturing table. RCPT (rate compatible punctured turbo) codes can be used in a similar way to RCPC codes. This paper considers the application of concatenated RS-RCPT codes and RCPT-HARQ (hybrid ARQ) schemes to W-CDMA.
{"title":"Rate compatible punctured turbo coding for W-CDMA","authors":"Hasung Kim, G. Struber","doi":"10.1109/ICPWC.2000.905790","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905790","url":null,"abstract":"3G mobile multimedia communication systems based on W-CDMA support a flexible and adaptive transmission capability to provide packet data service as well as voice service. Mobile multimedia communication requires a coding scheme that can accommodate varying code rate requirements. RCPC (rate compatible punctured convolutional) codes are one practical solution to adaptive coding. RCPC codes use a single rate-1/n convolutional encoder/decoder pair and the transmitter and receiver only need to share a puncturing table. RCPT (rate compatible punctured turbo) codes can be used in a similar way to RCPC codes. This paper considers the application of concatenated RS-RCPT codes and RCPT-HARQ (hybrid ARQ) schemes to W-CDMA.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126836692","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905780
K. Shanmugan, M. Sánchez, L. de Haro, M. Calvo
Many of the signal processing operations in the receivers for 3G CDMA systems depend on accurate estimates of the multipath fading channel. The performance of RAKE receivers and transmit diversity arrangements will degrade significantly if channel estimates are not accurate. Hence, one of the challenges in the design of 3G systems is accurate estimation of the underlying channel characteristics. The first generation of channel estimation algorithms proposed for 3G systems relied on using the pilot symbols. However, it has been shown through simulations that the small number of pilot symbols available for estimation leads to poor estimates, especially in fast fading conditions. In this paper, we introduce a Kalman filter algorithm for channel estimation that combines pilot symbol based estimates with a channel model. We derive an ARMA model for a typical mobile channel with a Jakes Doppler spectrum and use this model to derive the Kalman filtering algorithm. Through simulation and analysis we show that the Kalman filter algorithm reduces the variance of the channel estimate significantly compared to an estimate based on pilot symbols alone.
{"title":"Channel estimation for 3G wideband CDMA systems using the Kalman filtering algorithm","authors":"K. Shanmugan, M. Sánchez, L. de Haro, M. Calvo","doi":"10.1109/ICPWC.2000.905780","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905780","url":null,"abstract":"Many of the signal processing operations in the receivers for 3G CDMA systems depend on accurate estimates of the multipath fading channel. The performance of RAKE receivers and transmit diversity arrangements will degrade significantly if channel estimates are not accurate. Hence, one of the challenges in the design of 3G systems is accurate estimation of the underlying channel characteristics. The first generation of channel estimation algorithms proposed for 3G systems relied on using the pilot symbols. However, it has been shown through simulations that the small number of pilot symbols available for estimation leads to poor estimates, especially in fast fading conditions. In this paper, we introduce a Kalman filter algorithm for channel estimation that combines pilot symbol based estimates with a channel model. We derive an ARMA model for a typical mobile channel with a Jakes Doppler spectrum and use this model to derive the Kalman filtering algorithm. Through simulation and analysis we show that the Kalman filter algorithm reduces the variance of the channel estimate significantly compared to an estimate based on pilot symbols alone.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116481573","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905858
G. Yang, S. Kallel
In this paper, we have derived a novel joint rate detection and data decoding scheme for variable-rate data transmission in DS-CDMA communication systems. It is shown that this joint scheme is optimal in the sense of minimizing frame error rate. The results of a software simulation of the proposed joint scheme in a three-path Rayleigh fading channel are presented. Performance comparison between the proposed scheme and two existing rate detection schemes is also provided.
{"title":"Joint blind rate detection and data decoding scheme for CDMA mobile stations in frequency selective Rayleigh fading channels","authors":"G. Yang, S. Kallel","doi":"10.1109/ICPWC.2000.905858","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905858","url":null,"abstract":"In this paper, we have derived a novel joint rate detection and data decoding scheme for variable-rate data transmission in DS-CDMA communication systems. It is shown that this joint scheme is optimal in the sense of minimizing frame error rate. The results of a software simulation of the proposed joint scheme in a three-path Rayleigh fading channel are presented. Performance comparison between the proposed scheme and two existing rate detection schemes is also provided.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"36 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114030941","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905806
K. Kadambari, K. V. Rangarao, R. K. Mallik
We analyze a demodulation technique in which a sampled version of a BFSK signal is passed through an adaptive digital notch filter that estimates and tracks the instantaneous frequency of the incoming signal. By smoothing of the estimated instantaneous frequency sequence followed by a hard decision, we obtain the demodulated signal.
{"title":"Demodulation of BFSK signals by adaptive digital notch filtering","authors":"K. Kadambari, K. V. Rangarao, R. K. Mallik","doi":"10.1109/ICPWC.2000.905806","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905806","url":null,"abstract":"We analyze a demodulation technique in which a sampled version of a BFSK signal is passed through an adaptive digital notch filter that estimates and tracks the instantaneous frequency of the incoming signal. By smoothing of the estimated instantaneous frequency sequence followed by a hard decision, we obtain the demodulated signal.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126316796","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905864
V.D. Abraham, C. Rao
Transmission of multimedia data was one of the primary goals of the 3G cellular radio system. This necessitated very high-speed data links and the accommodation of the maximum possible number of users where the multipath delay spread encompassed many symbol intervals. Thus we saw that there was an urgent requirement to find more effective methods to combat the problems and channel impairments of the cellular radio system. Limiting Walsh sequence usage to class I data links eliminates the limitation of orthogonal code and class II links using PN sequences. Finally, self recovering (blind) channel estimation is adopted as no training sequence is required for initial adjustment of the equalizer coefficients, thus saving bandwidth. In this approach, sub-banding techniques are proposed for blind equalization. The sub-banding is carried out and the correlation between the method adopted and the accrued improvement in channel estimates is utilized.
{"title":"Optimization of spreading code and estimation of channel capacity in multi-code CDMA downlink","authors":"V.D. Abraham, C. Rao","doi":"10.1109/ICPWC.2000.905864","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905864","url":null,"abstract":"Transmission of multimedia data was one of the primary goals of the 3G cellular radio system. This necessitated very high-speed data links and the accommodation of the maximum possible number of users where the multipath delay spread encompassed many symbol intervals. Thus we saw that there was an urgent requirement to find more effective methods to combat the problems and channel impairments of the cellular radio system. Limiting Walsh sequence usage to class I data links eliminates the limitation of orthogonal code and class II links using PN sequences. Finally, self recovering (blind) channel estimation is adopted as no training sequence is required for initial adjustment of the equalizer coefficients, thus saving bandwidth. In this approach, sub-banding techniques are proposed for blind equalization. The sub-banding is carried out and the correlation between the method adopted and the accrued improvement in channel estimates is utilized.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121794402","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 : 2000-12-17DOI: 10.1109/ICPWC.2000.905789
R. Rao, Seungsin Lee
It has been empirically documented that data traffic over networks of various types exhibits fractal or self-similar behavior in many instances. Accurate analysis of traffic density and estimation of buffer size must take into account this self-similar nature. There is ongoing research on generating self-similar data for use in simulation and modeling of network traffic. This paper demonstrates that the novel models proposed by Zhao and Rao (1998, 1999) for constructing purely discrete-time self-similar processes and linear scale-invariant (LSI) systems lend themselves to the synthesis of data whose self-similarity parameters match those observed in network traffic. The paper provides theoretical development and experimental results.
{"title":"Self-similar network traffic characterization through linear scale-invariant system models","authors":"R. Rao, Seungsin Lee","doi":"10.1109/ICPWC.2000.905789","DOIUrl":"https://doi.org/10.1109/ICPWC.2000.905789","url":null,"abstract":"It has been empirically documented that data traffic over networks of various types exhibits fractal or self-similar behavior in many instances. Accurate analysis of traffic density and estimation of buffer size must take into account this self-similar nature. There is ongoing research on generating self-similar data for use in simulation and modeling of network traffic. This paper demonstrates that the novel models proposed by Zhao and Rao (1998, 1999) for constructing purely discrete-time self-similar processes and linear scale-invariant (LSI) systems lend themselves to the synthesis of data whose self-similarity parameters match those observed in network traffic. The paper provides theoretical development and experimental results.","PeriodicalId":260472,"journal":{"name":"2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132354740","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}
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