Pub Date : 2003-10-15DOI: 10.1109/TENCON.2003.1273282
P. Rao, R. Deekshit
An novel method of generating one-line diagrams of radial distribution systems in the form of a visibility graph is proposed. An algorithm that automatically generates an aesthetically 'pleasing' and 'readable' visibility diagram is presented. In addition to the basic property of a visibility graph that nodes and edges be represented by axis-parallel horizontal and vertical lines, respectively, a new set of layout specifications (aesthetic criteria) suitable for easy visualization of the distribution system have been proposed. This work is based on the premise that, in general, the network data of distribution systems does not contain any geographical information of node locations. Therefore the algorithm assumes that only the identity of the terminal nodes of all the edges are known. The proposed algorithm automatically determines node positions such that the specified aesthetic criteria are satisfied.
{"title":"Visibility representation of distribution system one-line diagrams","authors":"P. Rao, R. Deekshit","doi":"10.1109/TENCON.2003.1273282","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273282","url":null,"abstract":"An novel method of generating one-line diagrams of radial distribution systems in the form of a visibility graph is proposed. An algorithm that automatically generates an aesthetically 'pleasing' and 'readable' visibility diagram is presented. In addition to the basic property of a visibility graph that nodes and edges be represented by axis-parallel horizontal and vertical lines, respectively, a new set of layout specifications (aesthetic criteria) suitable for easy visualization of the distribution system have been proposed. This work is based on the premise that, in general, the network data of distribution systems does not contain any geographical information of node locations. Therefore the algorithm assumes that only the identity of the terminal nodes of all the edges are known. The proposed algorithm automatically determines node positions such that the specified aesthetic criteria are satisfied.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128959561","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273280
K. Visakha, D. Thukaram, L. Jenkins, H. Khincha
Electric power systems are exposed to various contingencies. Network contingencies often contribute to overloading of network branches, unsatisfactory voltages and also leading to problems of stability/voltage collapse. To maintain security of the systems, it is desirable to estimate the effect of contingencies and plan suitable measures to improve system security/stability. The paper presents an approach for selection of UPFC (unified power flow controller) suitable locations considering normal and network contingencies after evaluating the degree of severity of the contingencies. The ranking is evaluated using composite criteria based fuzzy logic for eliminating masking effects. The selection of UPFC suitable locations uses the criteria on the basis of improved system security/stability. The proposed approach for selection of UPFC suitable locations has been tested under simulated conditions on a few sample power systems and the results for a real life 36-node equivalent EHV power network are presented for illustration purposes.
{"title":"Selection of UPFC suitable locations for system security improvement under normal and network contingencies","authors":"K. Visakha, D. Thukaram, L. Jenkins, H. Khincha","doi":"10.1109/TENCON.2003.1273280","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273280","url":null,"abstract":"Electric power systems are exposed to various contingencies. Network contingencies often contribute to overloading of network branches, unsatisfactory voltages and also leading to problems of stability/voltage collapse. To maintain security of the systems, it is desirable to estimate the effect of contingencies and plan suitable measures to improve system security/stability. The paper presents an approach for selection of UPFC (unified power flow controller) suitable locations considering normal and network contingencies after evaluating the degree of severity of the contingencies. The ranking is evaluated using composite criteria based fuzzy logic for eliminating masking effects. The selection of UPFC suitable locations uses the criteria on the basis of improved system security/stability. The proposed approach for selection of UPFC suitable locations has been tested under simulated conditions on a few sample power systems and the results for a real life 36-node equivalent EHV power network are presented for illustration purposes.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129094121","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273247
M. Jacob, J. Mazierska, S. Takeuchi
Superconducting filters show many advantages over conventional filters such as higher selectivity, better out-of-band rejection and less interference between adjacent channels. Using ideas of a modified hairpin, the Chebyshev approximation and cross coupling between non-adjacent resonators, we have designed a 12-pole superconducting filter for centre frequency of 1.84 GHz and bandwidth of 5 MHz. The filter utilises YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films on a 58 mm /spl times/ 14 mm /spl times/ 0.3 mm LaAlO/sub 3/ substrate, 0.3 mm thick. The simulated passband insertion loss of the filter is 0.1 dB and the out-of-band rejection is 50 dB at 1 MHz from the passband.
与传统滤波器相比，超导滤波器具有更高的选择性、更好的带外抑制和更少的相邻信道干扰等优点。利用改进发夹、切比舍夫近似和非相邻谐振腔间交叉耦合的思想，设计了一个中心频率为1.84 GHz、带宽为5 MHz的12极超导滤波器。该过滤器利用YBa/sub 2/Cu/sub 3/O/sub 7-/spl δ //薄膜在58 mm /spl倍/ 14 mm /spl倍/ 0.3 mm LaAlO/sub 3/基片上，厚度为0.3 mm。该滤波器的模拟通带插入损耗为0.1 dB，带外抑制为50 dB，距离通带1mhz。
{"title":"Miniaturized superconducting filter for mobile communications","authors":"M. Jacob, J. Mazierska, S. Takeuchi","doi":"10.1109/TENCON.2003.1273247","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273247","url":null,"abstract":"Superconducting filters show many advantages over conventional filters such as higher selectivity, better out-of-band rejection and less interference between adjacent channels. Using ideas of a modified hairpin, the Chebyshev approximation and cross coupling between non-adjacent resonators, we have designed a 12-pole superconducting filter for centre frequency of 1.84 GHz and bandwidth of 5 MHz. The filter utilises YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films on a 58 mm /spl times/ 14 mm /spl times/ 0.3 mm LaAlO/sub 3/ substrate, 0.3 mm thick. The simulated passband insertion loss of the filter is 0.1 dB and the out-of-band rejection is 50 dB at 1 MHz from the passband.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129132270","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273117
S. Hasan, M. Bettayeb
This paper presents a novel fully pipelined parallel processing VLSI architecture for the order-recursive estimation of higher order statistics(HOS) in real-time. Compared to other recent work in array computation of HOS this approach presents a fine-grained systolic VLSI architecture using simple arithmetic elements & delay elements. Also, compared to previous work which mostly dwelt on 4th & lower order statistics, this work presents an open ended upwardly compatible architectural engine which can generate HOS for any high order. The through-put of this proposed HOS engine is only limited by a multiplication interval. Hence using today's deep subquarter micron CMOS process technology, through-puts in the range of 500 MHz to 1 GHz can be achieved for this HOS engine.
{"title":"An order-recursive pipelined real-time VLSI HOS engine for system-on-chip implementation","authors":"S. Hasan, M. Bettayeb","doi":"10.1109/TENCON.2003.1273117","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273117","url":null,"abstract":"This paper presents a novel fully pipelined parallel processing VLSI architecture for the order-recursive estimation of higher order statistics(HOS) in real-time. Compared to other recent work in array computation of HOS this approach presents a fine-grained systolic VLSI architecture using simple arithmetic elements & delay elements. Also, compared to previous work which mostly dwelt on 4th & lower order statistics, this work presents an open ended upwardly compatible architectural engine which can generate HOS for any high order. The through-put of this proposed HOS engine is only limited by a multiplication interval. Hence using today's deep subquarter micron CMOS process technology, through-puts in the range of 500 MHz to 1 GHz can be achieved for this HOS engine.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130912841","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273354
N. Panigrahi, R.K. Sharma
Surface tessellation is an important prerequisite for much analytical software. Also, tessellating a surface gives good visualization in the computer. The process of surface tessellation in general and surface triangulation in particular is a tricky process if an unstructured mesh is to be generated and becomes more intriguing if the surface under consideration involves holes and subsurfaces inside it. The paper presents the implementation of an algorithm for surface tessellation. The algorithm generates constrained Delaunay triangulation, an unstructured grid of a two dimensional surface involving holes. The generalized algorithm uses a simple data format to describe the domain known as planar straight line graph (PSLG) which is a collection of points and edges.
{"title":"An algorithm for tessellation of 2D planar domain with holes","authors":"N. Panigrahi, R.K. Sharma","doi":"10.1109/TENCON.2003.1273354","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273354","url":null,"abstract":"Surface tessellation is an important prerequisite for much analytical software. Also, tessellating a surface gives good visualization in the computer. The process of surface tessellation in general and surface triangulation in particular is a tricky process if an unstructured mesh is to be generated and becomes more intriguing if the surface under consideration involves holes and subsurfaces inside it. The paper presents the implementation of an algorithm for surface tessellation. The algorithm generates constrained Delaunay triangulation, an unstructured grid of a two dimensional surface involving holes. The generalized algorithm uses a simple data format to describe the domain known as planar straight line graph (PSLG) which is a collection of points and edges.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127622466","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273265
K. Subramanian, K. Hari
We propose a matrix model for the interleaved orthogonal frequency division multiplexing system (IOFDM). Using this model, we show that the interleaving scheme originally proposed for IOFDM is not unique in terms of preserving system complexity. We further show that a class of interleaving matrices yields IOFDM systems with the same complexity as the original IOFDM system. Furthermore, we show that the interleaving scheme does not affect the BER performance of the system as long as the interleaving matrix is unitary.
{"title":"Alternative interleaving schemes for interleaved orthogonal frequency division multiplexing","authors":"K. Subramanian, K. Hari","doi":"10.1109/TENCON.2003.1273265","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273265","url":null,"abstract":"We propose a matrix model for the interleaved orthogonal frequency division multiplexing system (IOFDM). Using this model, we show that the interleaving scheme originally proposed for IOFDM is not unique in terms of preserving system complexity. We further show that a class of interleaving matrices yields IOFDM systems with the same complexity as the original IOFDM system. Furthermore, we show that the interleaving scheme does not affect the BER performance of the system as long as the interleaving matrix is unitary.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121395187","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273289
S. Thiruvengadam, A. Karthikeyan, N. Muthuraja, V. Vinothkumar, V. Abhaikumar
Chaotic spreading sequences are used in spread spectrum communication systems due to their potential advantage over the conventional pseudo-noise sequences in terms of security and synchronization. This paper uses a class of chaotic binary sequences as the spreading waveforms in a direct sequence code division multiple access system. The loss of orthogonality between spreading waveforms in fading multipath channels is mitigated by employing multiuser detection with multiple transmit and receive antennas. The performance of the system with space time multiuser detection is analyzed in fading multipath channels with additive white Gaussian noise. The simulation results show that the DS-CDMA system with chaotic sequence having prescribed statistical properties can accommodate more users for a fixed length of spreading sequence.
{"title":"Performance analysis of DS-CDMA system with space-time multiuser detection using a class of chaotic spreading sequences","authors":"S. Thiruvengadam, A. Karthikeyan, N. Muthuraja, V. Vinothkumar, V. Abhaikumar","doi":"10.1109/TENCON.2003.1273289","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273289","url":null,"abstract":"Chaotic spreading sequences are used in spread spectrum communication systems due to their potential advantage over the conventional pseudo-noise sequences in terms of security and synchronization. This paper uses a class of chaotic binary sequences as the spreading waveforms in a direct sequence code division multiple access system. The loss of orthogonality between spreading waveforms in fading multipath channels is mitigated by employing multiuser detection with multiple transmit and receive antennas. The performance of the system with space time multiuser detection is analyzed in fading multipath channels with additive white Gaussian noise. The simulation results show that the DS-CDMA system with chaotic sequence having prescribed statistical properties can accommodate more users for a fixed length of spreading sequence.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"56 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126258257","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273421
L. Behera, S. Kumar, Supriyo Das
This paper discusses three learning algorithms to train recurrent neural networks for identification of nonlinear dynamical systems. We select memory neural networks(MNN) topology for the recurrent network in our work. MNNs are themselves dynamical systems that have internal memory obtained by adding trainable temporal elements to feed-forward networks. Three learning procedures namely back-propagation through time (BPTT), real time recurrent learning (RTRL) and extended Kalman filtering (EKF) are used for adjusting the weights in MNN to train such networks to identify the plant. The relative effectiveness of different learning algorithms have been discussed by comparing the mean square error associated with them and corresponding computational requirements. The simulation results show that RTRL algorithm is efficient for training MNNs to model nonlinear dynamical systems by considering both computational complexity and modelling accuracy. Eventhough, the accuracy of system identification is best with EKF, but it has the drawback of being computationally intensive.
{"title":"Identification of nonlinear dynamical systems using recurrent neural networks","authors":"L. Behera, S. Kumar, Supriyo Das","doi":"10.1109/TENCON.2003.1273421","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273421","url":null,"abstract":"This paper discusses three learning algorithms to train recurrent neural networks for identification of nonlinear dynamical systems. We select memory neural networks(MNN) topology for the recurrent network in our work. MNNs are themselves dynamical systems that have internal memory obtained by adding trainable temporal elements to feed-forward networks. Three learning procedures namely back-propagation through time (BPTT), real time recurrent learning (RTRL) and extended Kalman filtering (EKF) are used for adjusting the weights in MNN to train such networks to identify the plant. The relative effectiveness of different learning algorithms have been discussed by comparing the mean square error associated with them and corresponding computational requirements. The simulation results show that RTRL algorithm is efficient for training MNNs to model nonlinear dynamical systems by considering both computational complexity and modelling accuracy. Eventhough, the accuracy of system identification is best with EKF, but it has the drawback of being computationally intensive.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116145828","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273276
R. Nagarajan, S. Yaacob, G. Sainarayanan
The role of object identification in a sonification system for navigation assistance to the visually impaired (NAVI) is discussed. The developed system includes a single board processing system (SBPS), vision sensor mounted on headgear and stereo earphones. The vision sensor captures the vision information in front of the blind user. The captured image is processed to identify the object in the image. Object identification is achieved by a real time image processing methodology using fuzzy algorithms. The processed image is mapped onto stereo acoustic patterns and transferred to the stereo earphones in the system. Blind individuals were trained with NAVI system and tested for obstacle identification. Suggestions from the blind volunteers regarding the pleasantness and discrimination of the sound pattern were incorporated in the prototype. With object identification, the discrimination of object and background by sound is found to be easier compared to sound produced from the unprocessed image.
{"title":"Role of object identification in sonification system for visually impaired","authors":"R. Nagarajan, S. Yaacob, G. Sainarayanan","doi":"10.1109/TENCON.2003.1273276","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273276","url":null,"abstract":"The role of object identification in a sonification system for navigation assistance to the visually impaired (NAVI) is discussed. The developed system includes a single board processing system (SBPS), vision sensor mounted on headgear and stereo earphones. The vision sensor captures the vision information in front of the blind user. The captured image is processed to identify the object in the image. Object identification is achieved by a real time image processing methodology using fuzzy algorithms. The processed image is mapped onto stereo acoustic patterns and transferred to the stereo earphones in the system. Blind individuals were trained with NAVI system and tested for obstacle identification. Suggestions from the blind volunteers regarding the pleasantness and discrimination of the sound pattern were incorporated in the prototype. With object identification, the discrimination of object and background by sound is found to be easier compared to sound produced from the unprocessed image.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116664839","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 : 2003-10-15DOI: 10.1109/TENCON.2003.1273278
A. Negi, C. K. Chereddi
Telugu is one of the prominent scripts in India and Asia. We propose an OCR system for Telugu based on the candidate search and elimination technique. The initial candidates for recognition are found by applying a zoning method on input glyphs. We propose cavities as a structural approach suited specifically for Telugu script, where cavity vectors are used to prune the candidates found by zoning. A final template matching stage using controlled nonlinear normalization is performed to conclude the search process. The search can be concluded, at any stage, whenever a unique candidate is found. A recognition accuracy of 97-98% was achieved on real images scanned from Telugu literature.
{"title":"Candidate search and elimination approach for Telugu OCR","authors":"A. Negi, C. K. Chereddi","doi":"10.1109/TENCON.2003.1273278","DOIUrl":"https://doi.org/10.1109/TENCON.2003.1273278","url":null,"abstract":"Telugu is one of the prominent scripts in India and Asia. We propose an OCR system for Telugu based on the candidate search and elimination technique. The initial candidates for recognition are found by applying a zoning method on input glyphs. We propose cavities as a structural approach suited specifically for Telugu script, where cavity vectors are used to prune the candidates found by zoning. A final template matching stage using controlled nonlinear normalization is performed to conclude the search process. The search can be concluded, at any stage, whenever a unique candidate is found. A recognition accuracy of 97-98% was achieved on real images scanned from Telugu literature.","PeriodicalId":405847,"journal":{"name":"TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124920063","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：