Pub Date : 2021-07-27DOI: 10.1109/NCC52529.2021.9530148
Divyanshu Bhardwai, A. Bhattacharya, Bidisha Dasgupta
In this article, one new frequency reconfigurable antenna is presented. The antenna geometry comprises an annular ring shaped slot loaded rectangular patch antenna and two p-i-n diode switches. The antenna operates over 2.4 – 8.4 GHz (S band, C band, and partially in X band). The frequency hopping over the mentioned bandwidth is possible by changing switching p-i-n diode states. The proposed antenna can be used for future wireless applications such as an electromagnetic sensor for 5G and also for Cognitive Radio applications.
{"title":"A Compact Reconfigurable Slot-Loaded Printed Antenna for Future Wireless Applications","authors":"Divyanshu Bhardwai, A. Bhattacharya, Bidisha Dasgupta","doi":"10.1109/NCC52529.2021.9530148","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530148","url":null,"abstract":"In this article, one new frequency reconfigurable antenna is presented. The antenna geometry comprises an annular ring shaped slot loaded rectangular patch antenna and two p-i-n diode switches. The antenna operates over 2.4 – 8.4 GHz (S band, C band, and partially in X band). The frequency hopping over the mentioned bandwidth is possible by changing switching p-i-n diode states. The proposed antenna can be used for future wireless applications such as an electromagnetic sensor for 5G and also for Cognitive Radio applications.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124473303","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530080
Khush Agrawal, Rohit Lal, Himanshu Patil, Surender Kannaiyan, Deep Gupta
This paper presents a novel mechanism, DeepSCT, to handle the long-term object tracking problem in Computer Vision. The paper builds around the premise that the classical tracking algorithms can handle short-term tracking problems efficiently; however, they fail in the case of long-term tracking due to several environmental disturbances like occlusion and out-of-frame going targets. The relatively newer Deep Learning based trackers have higher efficacy but suffer from working in real-time on low-end hardware. We try to fuse the two methods in a unique way such that the resulting algorithm has higher efficiency and accuracy simultaneously. We present a modular mechanism, which can accommodate improvements in its sub-blocks. The algorithm was tested on the VisDrone-SOT2019 dataset for a person tracking task. We quantitatively and qualitatively show that DeepSCT significantly improved classical algorithms' performance in short-term and long-term tracking problems.
{"title":"DeepSCT: Deep Learning Based Self Correcting Object Tracking Mechanism","authors":"Khush Agrawal, Rohit Lal, Himanshu Patil, Surender Kannaiyan, Deep Gupta","doi":"10.1109/NCC52529.2021.9530080","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530080","url":null,"abstract":"This paper presents a novel mechanism, DeepSCT, to handle the long-term object tracking problem in Computer Vision. The paper builds around the premise that the classical tracking algorithms can handle short-term tracking problems efficiently; however, they fail in the case of long-term tracking due to several environmental disturbances like occlusion and out-of-frame going targets. The relatively newer Deep Learning based trackers have higher efficacy but suffer from working in real-time on low-end hardware. We try to fuse the two methods in a unique way such that the resulting algorithm has higher efficiency and accuracy simultaneously. We present a modular mechanism, which can accommodate improvements in its sub-blocks. The algorithm was tested on the VisDrone-SOT2019 dataset for a person tracking task. We quantitatively and qualitatively show that DeepSCT significantly improved classical algorithms' performance in short-term and long-term tracking problems.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124757960","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530127
Ankur Bansal, Sudhakar Modem
In this paper, we investigate the performance of three user network with two-stage non-orthogonal multiple access (NOMA) scheme. In particular, the outage performance is analyzed by considering full efficiency information transmission protocol, where each user receives its own data symbol in every slot. We investigate outage performance metric at each user, and obtained closed-form expressions. Moreover, a novel fragmental outage probability at near users is evaluated, which is useful for obtaining optimum NOMA power allocation coefficients. The results demonstrate that the considered scheme outperform conventional NOMA and optimal NOMA parameter selection maximizes the system performance. Simulation results corroborate the derived analytical expressions.
{"title":"Performance of Two Stage Cooperative NOMA Transmission for Full-Efficient Three User Network","authors":"Ankur Bansal, Sudhakar Modem","doi":"10.1109/NCC52529.2021.9530127","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530127","url":null,"abstract":"In this paper, we investigate the performance of three user network with two-stage non-orthogonal multiple access (NOMA) scheme. In particular, the outage performance is analyzed by considering full efficiency information transmission protocol, where each user receives its own data symbol in every slot. We investigate outage performance metric at each user, and obtained closed-form expressions. Moreover, a novel fragmental outage probability at near users is evaluated, which is useful for obtaining optimum NOMA power allocation coefficients. The results demonstrate that the considered scheme outperform conventional NOMA and optimal NOMA parameter selection maximizes the system performance. Simulation results corroborate the derived analytical expressions.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125019094","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530139
Santosh Kumar, Pintu Kumar, Rakesh Ranjan
An aluminum gallium arsenide (AlGaAs) based hybrid metal insulator plasmonic waveguide (HMIPW) has been investigated to analyze the optical properties of fundamental and higher order modes, such as real part of effective index, normalized effective mode area, and propagation length at 1550 nm of wavelength. The modal investigations have been done by varying the thicknesses of high index, low-index, and metal regions. The propagation length, up to 480 µm has been achieved, for the fundamental mode propagation. The multi-mode analysis presented in the current work can be extended for the analysis of biosensors, multimode interferometer, high speed optical signal processing, etc.
{"title":"Mode Analysis of AlGaAs Based Hybrid Metal Insulator Plasmonic Waveguide with Nanoscale Confinement","authors":"Santosh Kumar, Pintu Kumar, Rakesh Ranjan","doi":"10.1109/NCC52529.2021.9530139","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530139","url":null,"abstract":"An aluminum gallium arsenide (AlGaAs) based hybrid metal insulator plasmonic waveguide (HMIPW) has been investigated to analyze the optical properties of fundamental and higher order modes, such as real part of effective index, normalized effective mode area, and propagation length at 1550 nm of wavelength. The modal investigations have been done by varying the thicknesses of high index, low-index, and metal regions. The propagation length, up to 480 µm has been achieved, for the fundamental mode propagation. The multi-mode analysis presented in the current work can be extended for the analysis of biosensors, multimode interferometer, high speed optical signal processing, etc.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128366356","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530150
Mrinmoy Bhattacharjee, S. Prasanna, P. Guha
Detection of speech overlapped with music is a challenging task. This work deals with discriminating clean speech from speech overlapped with low-energy music. The overlapped signals are generated synthetically. An enhanced spectrogram representation called Pyknogram has been explored for the current task. Pyknograms have been previously used in overlapped speech detection. The classification is performed using a neural network that is designed with only convolutional layers. The performance of Pyknograms at various high SNR levels is compared with that of discrete fourier transform based spectrograms. The classification system is benchmarked on three publicly available datasets, viz., GTZAN, Scheirer-slaney and MUSAN. The Pyknogram representation with the fully convolutional classifier performs well, both individually and in combination with spectrograms.
{"title":"Detection of Speech Overlapped with Low-Energy Music using Pyknograms","authors":"Mrinmoy Bhattacharjee, S. Prasanna, P. Guha","doi":"10.1109/NCC52529.2021.9530150","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530150","url":null,"abstract":"Detection of speech overlapped with music is a challenging task. This work deals with discriminating clean speech from speech overlapped with low-energy music. The overlapped signals are generated synthetically. An enhanced spectrogram representation called Pyknogram has been explored for the current task. Pyknograms have been previously used in overlapped speech detection. The classification is performed using a neural network that is designed with only convolutional layers. The performance of Pyknograms at various high SNR levels is compared with that of discrete fourier transform based spectrograms. The classification system is benchmarked on three publicly available datasets, viz., GTZAN, Scheirer-slaney and MUSAN. The Pyknogram representation with the fully convolutional classifier performs well, both individually and in combination with spectrograms.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132101546","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530088
P. Kachare, P. C. Pandey
Spectral variation function is used to detect salient segments (segments with sharp spectral transitions). It is calculated from cosine of the angle between the averaged feature vectors of the adjacent segments. A modified version of this function is presented for variable time-scale modification of the speech signal. It uses the magnitude spectrum smoothed by auditory critical band filters and a small offset in the normalization for the angle cosine. Test results showed that the modified function detects spectral saliencies and does not have spurious peaks. It is applied for variable time-scale modification without altering the overall duration. Listening tests showed significantly better speech quality for processing using the modified function.
{"title":"A Spectral Variation Function for Variable Time-Scale Modification of Speech","authors":"P. Kachare, P. C. Pandey","doi":"10.1109/NCC52529.2021.9530088","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530088","url":null,"abstract":"Spectral variation function is used to detect salient segments (segments with sharp spectral transitions). It is calculated from cosine of the angle between the averaged feature vectors of the adjacent segments. A modified version of this function is presented for variable time-scale modification of the speech signal. It uses the magnitude spectrum smoothed by auditory critical band filters and a small offset in the normalization for the angle cosine. Test results showed that the modified function detects spectral saliencies and does not have spurious peaks. It is applied for variable time-scale modification without altering the overall duration. Listening tests showed significantly better speech quality for processing using the modified function.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"2006 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121590876","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530038
M. Das, Deep Gupta, P. Radeva, Ashwini M. Bakde
Fusion of complementary anatomical and functional information present in multi-modal medical images provides improved visualization of various bodily structures and assists radiologist to infer more factual diagnostic interpretations. Inspired by the neuronal assemblies of mammal's visual cortex, spiking neural models such as dual-channel pulse coupled neural network (DCPCNN) and coupled neural P (CNP) system efficiently extract and integrate complementary information present in the source images. But, these models have various free parameters which are set using hit and trial approach in most of the conventional fusion methods. This paper presents an optimized multi-modal medical image fusion method in non-subsampled sheartlet transform (NSST) domain wherein the free parameters of both DCPCNN and CNP system are optimized using multi-objective grey wolf optimization (MOGWO). Extensive experiments are performed on various anatomical-functional images. Subjective and objective result analysis indicate that the proposed method effectively fuse important diagnostic information of the source images and also outperforms other state of the art fusion methods.
{"title":"Optimized Bio-inspired Spiking Neural Models based Anatomical and Functional Neurological Image Fusion in NSST Domain","authors":"M. Das, Deep Gupta, P. Radeva, Ashwini M. Bakde","doi":"10.1109/NCC52529.2021.9530038","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530038","url":null,"abstract":"Fusion of complementary anatomical and functional information present in multi-modal medical images provides improved visualization of various bodily structures and assists radiologist to infer more factual diagnostic interpretations. Inspired by the neuronal assemblies of mammal's visual cortex, spiking neural models such as dual-channel pulse coupled neural network (DCPCNN) and coupled neural P (CNP) system efficiently extract and integrate complementary information present in the source images. But, these models have various free parameters which are set using hit and trial approach in most of the conventional fusion methods. This paper presents an optimized multi-modal medical image fusion method in non-subsampled sheartlet transform (NSST) domain wherein the free parameters of both DCPCNN and CNP system are optimized using multi-objective grey wolf optimization (MOGWO). Extensive experiments are performed on various anatomical-functional images. Subjective and objective result analysis indicate that the proposed method effectively fuse important diagnostic information of the source images and also outperforms other state of the art fusion methods.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"61 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114252772","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 : 2021-07-27DOI: 10.1109/ncc52529.2021.9530019
{"title":"[Copyright notice]","authors":"","doi":"10.1109/ncc52529.2021.9530019","DOIUrl":"https://doi.org/10.1109/ncc52529.2021.9530019","url":null,"abstract":"","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133575621","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530060
Anuj Kumar Yadav, Manideep Mamindlapally, Amitalok J. Budkuley, M. Mishra
In the commitment problem, two mutually distrustful parties Alice and Bob interact in a two-phase protocol, viz., commit and reveal phase, to achieve commitment over a bit string that Alice possesses. The protocol successfully achieves commitment if, firstly, Alice can commit to sharing a string with Bob, with the guarantee that this string remains hidden from Bob until she chooses to reveal it to him. Secondly, when Alice does reveal a string, Bob is able to detect precisely whether the revealed string is different from the one Alice committed to sharing. Information-theoretically secure commitment is impossible if Alice and Bob communicate only noiselessly; however, communication using a noisy channel can be a resource to realize commitment. Even though a noisy channel may be available, it is possible that the corresponding channel law is imprecisely known or poorly characterized. We define and study a compound-binary symmetric channel (compound-BSC) which models such a scenario. A compound-BSC is a BSC whose transition probability is fixed but unknown to either party; the set of potential values which this transition probability can take, though, is known to both parties a priori. In this work, we completely characterize the maximum commitment throughput or commitment capacity of a compound-BSC. We provide an optimal, computationally-efficient scheme for our achievability, and we derive a converse for general alphabet compound DMCs, which is then specialized for compound-BSCs.
{"title":"Commitment over Compound Binary Symmetric Channels","authors":"Anuj Kumar Yadav, Manideep Mamindlapally, Amitalok J. Budkuley, M. Mishra","doi":"10.1109/NCC52529.2021.9530060","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530060","url":null,"abstract":"In the commitment problem, two mutually distrustful parties Alice and Bob interact in a two-phase protocol, viz., commit and reveal phase, to achieve commitment over a bit string that Alice possesses. The protocol successfully achieves commitment if, firstly, Alice can commit to sharing a string with Bob, with the guarantee that this string remains hidden from Bob until she chooses to reveal it to him. Secondly, when Alice does reveal a string, Bob is able to detect precisely whether the revealed string is different from the one Alice committed to sharing. Information-theoretically secure commitment is impossible if Alice and Bob communicate only noiselessly; however, communication using a noisy channel can be a resource to realize commitment. Even though a noisy channel may be available, it is possible that the corresponding channel law is imprecisely known or poorly characterized. We define and study a compound-binary symmetric channel (compound-BSC) which models such a scenario. A compound-BSC is a BSC whose transition probability is fixed but unknown to either party; the set of potential values which this transition probability can take, though, is known to both parties a priori. In this work, we completely characterize the maximum commitment throughput or commitment capacity of a compound-BSC. We provide an optimal, computationally-efficient scheme for our achievability, and we derive a converse for general alphabet compound DMCs, which is then specialized for compound-BSCs.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133614547","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 : 2021-07-27DOI: 10.1109/NCC52529.2021.9530022
A. Bora, Tourangbam Harishore Singh, Po-Tsang Huang
Traditionally, a wideband frequency hopping spread-spectrum (FHSS) system involves the use of analog mixers and oscillators for hopping the baseband signal to different higher frequencies. Such typical heterodyne receiver architectures have higher cost and form factors. Motivated by the recent development of direct radio-frequency (RF) data converters, this paper proposes an all-digital wideband orthogonal frequency division multiplexing (OFDM) based FHSS system using an RF direct sampling receiver architecture. The frequency-hopping is done in a two-stage process, with one at the baseband and the other at the carrier frequency to make it robust from any malicious attacks in the form of eavesdropping and jamming. The all-digital process of RF signal generation and detection in the system is verified over-the-air by using the RF sampling data converters of the Xilinx Ultrascale ZCU111 RFSoC board and Qorvo RF front-end. Later, a simulated bit error rate (BER) analysis of the system under a slow-fading channel and pilot-based channel estimation is carried out, which shows comparable performance with that of an analog FHSS system at radio frequencies.
{"title":"An All-Digital Wideband OFDM-based Frequency-hopping System using RF Sampling Data Converters","authors":"A. Bora, Tourangbam Harishore Singh, Po-Tsang Huang","doi":"10.1109/NCC52529.2021.9530022","DOIUrl":"https://doi.org/10.1109/NCC52529.2021.9530022","url":null,"abstract":"Traditionally, a wideband frequency hopping spread-spectrum (FHSS) system involves the use of analog mixers and oscillators for hopping the baseband signal to different higher frequencies. Such typical heterodyne receiver architectures have higher cost and form factors. Motivated by the recent development of direct radio-frequency (RF) data converters, this paper proposes an all-digital wideband orthogonal frequency division multiplexing (OFDM) based FHSS system using an RF direct sampling receiver architecture. The frequency-hopping is done in a two-stage process, with one at the baseband and the other at the carrier frequency to make it robust from any malicious attacks in the form of eavesdropping and jamming. The all-digital process of RF signal generation and detection in the system is verified over-the-air by using the RF sampling data converters of the Xilinx Ultrascale ZCU111 RFSoC board and Qorvo RF front-end. Later, a simulated bit error rate (BER) analysis of the system under a slow-fading channel and pilot-based channel estimation is carried out, which shows comparable performance with that of an analog FHSS system at radio frequencies.","PeriodicalId":414087,"journal":{"name":"2021 National Conference on Communications (NCC)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115768918","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：