Pub Date : 2019-07-01DOI: 10.1109/TSP.2019.8769055
Petr Dejdar, P. Munster, T. Horváth
The paper describes the possibilities of data acquisition and data processing from optical sensing systems. There are some data acquisition cards and their disadvantages when used for more complex single fiber sensor systems in the paper. It is suitable to use some open source hardware because commercially available data acquisition cards are more complex and universal which means they have several different inputs/outputs and large dimensions. STEMLab 125-14 (Red Pitaya) appears to be the most suitable solution because offers 2 analog inputs and 2 analog outputs. Compare to standard data processing systems, this is supposed to be an advantage in preprocessing data using programmable logic. This can reduce the volume of transmitted data and can also speed up processing. Thus, the measurement system will be smaller and cheaper. The device contains DA converters, therefore pulses might be generated using the same clock which enables synchronization of backscatter signal.
{"title":"High-speed Data Acquisition and Signal Processing Using Cost Effective ARM + FPGA Processors","authors":"Petr Dejdar, P. Munster, T. Horváth","doi":"10.1109/TSP.2019.8769055","DOIUrl":"https://doi.org/10.1109/TSP.2019.8769055","url":null,"abstract":"The paper describes the possibilities of data acquisition and data processing from optical sensing systems. There are some data acquisition cards and their disadvantages when used for more complex single fiber sensor systems in the paper. It is suitable to use some open source hardware because commercially available data acquisition cards are more complex and universal which means they have several different inputs/outputs and large dimensions. STEMLab 125-14 (Red Pitaya) appears to be the most suitable solution because offers 2 analog inputs and 2 analog outputs. Compare to standard data processing systems, this is supposed to be an advantage in preprocessing data using programmable logic. This can reduce the volume of transmitted data and can also speed up processing. Thus, the measurement system will be smaller and cheaper. The device contains DA converters, therefore pulses might be generated using the same clock which enables synchronization of backscatter signal.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127095951","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 : 2019-07-01DOI: 10.1109/TSP.2019.8769113
G. Romano
We consider the problem of estimation of signal-to-noise ratio (SNR) with a real deterministic sinusoid with unknown frequency, phase and amplitude in additive Gaussian noise of unknown variance. The method of moments, a general method to derive estimators based on high-order moments, is used to derive a blind SNR estimator that does not require the knowledge of the instantaneous frequency of the sinusoid, through separate estimation of signal and noise power. Cramer-Rao lower bounds (CRLBs) are also derived for estimators of signal and noise power and then, for SNR estimators. We show through numerical simulations the statistical performances of the estimators, that we compare to the corresponding CRLBs, and discuss their use in practical applications.
{"title":"Blind Signal-to-Noise Ratio Estimation of Real Sinusoid in Additive Noise","authors":"G. Romano","doi":"10.1109/TSP.2019.8769113","DOIUrl":"https://doi.org/10.1109/TSP.2019.8769113","url":null,"abstract":"We consider the problem of estimation of signal-to-noise ratio (SNR) with a real deterministic sinusoid with unknown frequency, phase and amplitude in additive Gaussian noise of unknown variance. The method of moments, a general method to derive estimators based on high-order moments, is used to derive a blind SNR estimator that does not require the knowledge of the instantaneous frequency of the sinusoid, through separate estimation of signal and noise power. Cramer-Rao lower bounds (CRLBs) are also derived for estimators of signal and noise power and then, for SNR estimators. We show through numerical simulations the statistical performances of the estimators, that we compare to the corresponding CRLBs, and discuss their use in practical applications.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126552658","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 : 2019-07-01DOI: 10.1109/TSP.2019.8768872
Furkan Durukan, Birhan Mert Güney, A. Özen
In this paper, color shift keying (CSK) modulation, which is selected as one of the modulation methods in visible light communication systems, is integrated with orthogonal frequency division multiplexing (OFDM) to increase the spectrum yield. However, the conventional fast Fourier transform (FFT) based OFDM needs that the CSK symbols be Hermitian symmetric, resulting in wasted bandwidth. In this study, it is proposed a real Fourier field based CSK OFDM technique using discrete Cosine transform (DCT), which can transform the real-value signal into a real-value signal and eliminate the need for Hermitian symmetry. Thus, the use of spectra has been doubled due to the removal of Hermitian symmetry in classical FFT-based OFDM systems. In order to test the achievement of the recommended CSK-modulated DCT-based OFDM (DCT-OFDM) and compare with the classical FFT-based OFDM and discrete sine transform (DST) based OFDM systems computer simulation studies are carried out in additive white Gaussian noise (AWGN) channel environment and a single path channel in indoor environment, where the transmitter and the receiver see each other (Line of sight, LOS). From the computer simulation outcomes, it is observed that approximately 17 dB of SNR gain is obtained with the proposed method for the 1E–3 BER value.
{"title":"A Novel CSK Modulated OFDM System for Visible Light Communication","authors":"Furkan Durukan, Birhan Mert Güney, A. Özen","doi":"10.1109/TSP.2019.8768872","DOIUrl":"https://doi.org/10.1109/TSP.2019.8768872","url":null,"abstract":"In this paper, color shift keying (CSK) modulation, which is selected as one of the modulation methods in visible light communication systems, is integrated with orthogonal frequency division multiplexing (OFDM) to increase the spectrum yield. However, the conventional fast Fourier transform (FFT) based OFDM needs that the CSK symbols be Hermitian symmetric, resulting in wasted bandwidth. In this study, it is proposed a real Fourier field based CSK OFDM technique using discrete Cosine transform (DCT), which can transform the real-value signal into a real-value signal and eliminate the need for Hermitian symmetry. Thus, the use of spectra has been doubled due to the removal of Hermitian symmetry in classical FFT-based OFDM systems. In order to test the achievement of the recommended CSK-modulated DCT-based OFDM (DCT-OFDM) and compare with the classical FFT-based OFDM and discrete sine transform (DST) based OFDM systems computer simulation studies are carried out in additive white Gaussian noise (AWGN) channel environment and a single path channel in indoor environment, where the transmitter and the receiver see each other (Line of sight, LOS). From the computer simulation outcomes, it is observed that approximately 17 dB of SNR gain is obtained with the proposed method for the 1E–3 BER value.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121479053","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 : 2019-07-01DOI: 10.1109/TSP.2019.8769062
Dumisani Ngwenya, B. T. Maharaj, A. Alfa
Analytic modelling of TCP congestion control has been a subject of intense research in the past two decades for both wireline and wireless high-speed Broadband networks. There has not been a single simple analytical approach that covers a wide range of TCP congestion control variants, making it hard to compare them against each other.. The contribution of this paper is generalization of a Markov model, previously used for TCP Cubic, so that it can also be used for TCP NewReno and a wide range of random loss rates. We also argue that the model can be easily extended to other mechanisms, even model-based mechanisms and those that are hard to define mathematically. We show that the results of the model tally with literature results. The model captures correctly the behaviour of TCP NewReno and TCP Cubic in environments with high random loss rates. We further confirm the results with NS3 simulation.
{"title":"Markov Based Computational Model for Performance Evaluation of Congestion Control Variants","authors":"Dumisani Ngwenya, B. T. Maharaj, A. Alfa","doi":"10.1109/TSP.2019.8769062","DOIUrl":"https://doi.org/10.1109/TSP.2019.8769062","url":null,"abstract":"Analytic modelling of TCP congestion control has been a subject of intense research in the past two decades for both wireline and wireless high-speed Broadband networks. There has not been a single simple analytical approach that covers a wide range of TCP congestion control variants, making it hard to compare them against each other.. The contribution of this paper is generalization of a Markov model, previously used for TCP Cubic, so that it can also be used for TCP NewReno and a wide range of random loss rates. We also argue that the model can be easily extended to other mechanisms, even model-based mechanisms and those that are hard to define mathematically. We show that the results of the model tally with literature results. The model captures correctly the behaviour of TCP NewReno and TCP Cubic in environments with high random loss rates. We further confirm the results with NS3 simulation.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131046977","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 : 2019-07-01DOI: 10.1109/TSP.2019.8769077
Jan Dorazil, K. Říha, M. Dutta
Analysis of the movement of the common carotid artery (CCA) wall in ultrasound sequences can be used for diagnosis of many cardiovascular diseases. In this paper we introduce a method for localization of the CCA wall contour (approximated by a circle) inside an ultrasound image, which can be used in real-time applications for initialization of an artery wall tracking method. First we detect a rectangular region of interest (ROI) using a recently proposed method based on the Viola-Jones detector. Next we perform an exhaustive search over all possible circles inside the ROI. Circle which maximizes a particular criterion represents the final estimate. Experimental results on a dataset of 145 ultrasound images show that the method outperforms a reference method based on the Hough transform in terms of precision and misdetection rates.
{"title":"Common Carotid Artery Wall Localization in B-mode Ultrasound Images for Initialization of Artery Wall Tracking Methods","authors":"Jan Dorazil, K. Říha, M. Dutta","doi":"10.1109/TSP.2019.8769077","DOIUrl":"https://doi.org/10.1109/TSP.2019.8769077","url":null,"abstract":"Analysis of the movement of the common carotid artery (CCA) wall in ultrasound sequences can be used for diagnosis of many cardiovascular diseases. In this paper we introduce a method for localization of the CCA wall contour (approximated by a circle) inside an ultrasound image, which can be used in real-time applications for initialization of an artery wall tracking method. First we detect a rectangular region of interest (ROI) using a recently proposed method based on the Viola-Jones detector. Next we perform an exhaustive search over all possible circles inside the ROI. Circle which maximizes a particular criterion represents the final estimate. Experimental results on a dataset of 145 ultrasound images show that the method outperforms a reference method based on the Hough transform in terms of precision and misdetection rates.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132903594","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 : 2019-07-01DOI: 10.1109/TSP.2019.8768812
R. Mîrsu, G. Simion, C. Căleanu, Oana Ursulescu, Ioana-Monica Pop-Calimanu
Deep Neural Networks and their associated learning paradigm, Deep Learning, represent one of the hottest approaches used in image understanding and recognition. As their performances depends quasi-linearly on the amount of available data, the typical case studies in the literature assume the availability of huge datasets. This paper proposes to analyze several deep neural networks (trained from the scratch or pre-trained), test their efficiency in the problem of hand gesture recognition, and compare the results to a state-of-the-art classical method, the bag of features, for the case of small databases.
{"title":"Deep Neural Networks vs Bag of Features for Hand Gesture Recognition","authors":"R. Mîrsu, G. Simion, C. Căleanu, Oana Ursulescu, Ioana-Monica Pop-Calimanu","doi":"10.1109/TSP.2019.8768812","DOIUrl":"https://doi.org/10.1109/TSP.2019.8768812","url":null,"abstract":"Deep Neural Networks and their associated learning paradigm, Deep Learning, represent one of the hottest approaches used in image understanding and recognition. As their performances depends quasi-linearly on the amount of available data, the typical case studies in the literature assume the availability of huge datasets. This paper proposes to analyze several deep neural networks (trained from the scratch or pre-trained), test their efficiency in the problem of hand gesture recognition, and compare the results to a state-of-the-art classical method, the bag of features, for the case of small databases.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128110704","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 : 2019-07-01DOI: 10.1109/TSP.2019.8768892
Alina Elena Marcu, R. Dobre, O. Datcu, G. Suciu, Je-Hui Oh
In the recent years, the conventional lighting systems are beginning to be replaced by LED lighting systems. In a Visible Light Communication (VLC) system, the visible light is used to provide a link between a transmitter, who is typically a LED, and a receiver, which is either a photodetector or an image sensor. The VLC can be used, besides illumination, for transferring data by changing very fast the light intensity of the LED and not to be perceived by the human eye as flicker. In recent applications, high frame rate cameras have begun to be used, but their disadvantage is the high cost. This paper proposes and experimentally validates a VLC solution that uses low frame rate camera and does not require a transmitter-receiver synchronization.
{"title":"Flicker Free VLC System with Automatic Code Resynchronization using Low Frame Rate Camera","authors":"Alina Elena Marcu, R. Dobre, O. Datcu, G. Suciu, Je-Hui Oh","doi":"10.1109/TSP.2019.8768892","DOIUrl":"https://doi.org/10.1109/TSP.2019.8768892","url":null,"abstract":"In the recent years, the conventional lighting systems are beginning to be replaced by LED lighting systems. In a Visible Light Communication (VLC) system, the visible light is used to provide a link between a transmitter, who is typically a LED, and a receiver, which is either a photodetector or an image sensor. The VLC can be used, besides illumination, for transferring data by changing very fast the light intensity of the LED and not to be perceived by the human eye as flicker. In recent applications, high frame rate cameras have begun to be used, but their disadvantage is the high cost. This paper proposes and experimentally validates a VLC solution that uses low frame rate camera and does not require a transmitter-receiver synchronization.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128178115","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 : 2019-07-01DOI: 10.1109/tsp.2019.8768855
{"title":"TSP 2019 Reviewers","authors":"","doi":"10.1109/tsp.2019.8768855","DOIUrl":"https://doi.org/10.1109/tsp.2019.8768855","url":null,"abstract":"","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128305340","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 : 2019-07-01DOI: 10.1109/TSP.2019.8768840
Pavel Mašek, Martin Stusek, Krystof Zeman, Radek Mozny, A. Ometov, Jiri Hosek
The Internet of Things (IoT) enables long-range outdoor networks, such as smart grid and municipal lighting, as well as short-range indoor systems for smart homes, residential security, and energy management. Wireless connectivity and standardized communication protocols become an essential technology baseline for these diverse IoT applications. The focus of this work is wireless connectivity for smart metering systems. One of the recent protocols in this field is Wireless M-BUS, which is being widely utilized for remote metering applications across Europe. Therefore, in this paper, we detail a novel multi-platform framework designed to serve as a data generator for the protocol in question. The developed software allows to construct Wireless M-Bus telegrams with a high level of detail according to the EN 13757-4 specification and then schedule them for periodic transmission. The evaluation of the data generator is done in real scenario by using previously developed prototype equipped with IQRF TR72DA communication module acting as a smart meter with implemented software framework. As a result, the evaluation of communication distance between the developed Wireless MBus prototype and commercial gateway was tested in case of indoor scenario at Brno University of Technology, Faculty of Electrical Engineering and Communication.
{"title":"A Perspective on Wireless M-Bus for Smart Electricity Grids","authors":"Pavel Mašek, Martin Stusek, Krystof Zeman, Radek Mozny, A. Ometov, Jiri Hosek","doi":"10.1109/TSP.2019.8768840","DOIUrl":"https://doi.org/10.1109/TSP.2019.8768840","url":null,"abstract":"The Internet of Things (IoT) enables long-range outdoor networks, such as smart grid and municipal lighting, as well as short-range indoor systems for smart homes, residential security, and energy management. Wireless connectivity and standardized communication protocols become an essential technology baseline for these diverse IoT applications. The focus of this work is wireless connectivity for smart metering systems. One of the recent protocols in this field is Wireless M-BUS, which is being widely utilized for remote metering applications across Europe. Therefore, in this paper, we detail a novel multi-platform framework designed to serve as a data generator for the protocol in question. The developed software allows to construct Wireless M-Bus telegrams with a high level of detail according to the EN 13757-4 specification and then schedule them for periodic transmission. The evaluation of the data generator is done in real scenario by using previously developed prototype equipped with IQRF TR72DA communication module acting as a smart meter with implemented software framework. As a result, the evaluation of communication distance between the developed Wireless MBus prototype and commercial gateway was tested in case of indoor scenario at Brno University of Technology, Faculty of Electrical Engineering and Communication.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131966179","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 : 2019-07-01DOI: 10.1109/TSP.2019.8768864
Alina L. Machidon, O. Machidon, P. Ogrutan
The human face exhibits a high level of complexity when it is regarded as a multidimensional visual model, leading to face recognition systems that require difficult and extensive computations for coding and decoding the face images. A well-established approach in this regard is based on using principle component analysis (PCA) for both feature extraction and face recognition, known as the eigenface approach. This technique, despite a good recognition rate, suffers from the disadvantage of high computation cost due to the complexity of the PCA algorithm. In this paper, we use a geometrical approximated PCA (gaPCA) algorithm for computing the eigenfaces for three different datasets. The face recognition task is performed using a similarity score based on the inverse Euclidean distance for the first two datasets and using a nerual network in the third case. All the results are compared to the case where standard PCA is used. These accuracy results show that gaPCA represents a viable alternative to the classical statistical approach for computing the principal components.
{"title":"Face Recognition Using Eigenfaces, Geometrical PCA Approximation and Neural Networks","authors":"Alina L. Machidon, O. Machidon, P. Ogrutan","doi":"10.1109/TSP.2019.8768864","DOIUrl":"https://doi.org/10.1109/TSP.2019.8768864","url":null,"abstract":"The human face exhibits a high level of complexity when it is regarded as a multidimensional visual model, leading to face recognition systems that require difficult and extensive computations for coding and decoding the face images. A well-established approach in this regard is based on using principle component analysis (PCA) for both feature extraction and face recognition, known as the eigenface approach. This technique, despite a good recognition rate, suffers from the disadvantage of high computation cost due to the complexity of the PCA algorithm. In this paper, we use a geometrical approximated PCA (gaPCA) algorithm for computing the eigenfaces for three different datasets. The face recognition task is performed using a similarity score based on the inverse Euclidean distance for the first two datasets and using a nerual network in the third case. All the results are compared to the case where standard PCA is used. These accuracy results show that gaPCA represents a viable alternative to the classical statistical approach for computing the principal components.","PeriodicalId":399087,"journal":{"name":"2019 42nd International Conference on Telecommunications and Signal Processing (TSP)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131986160","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：