Recently, image representations derived by convolutional neural networks(CNN) have achieved promising performance for instance retrieval, and they outperformthe traditional hand-crafted image features. However, most o...Recently, image representations derived by convolutional neural networks(CNN) have achieved promising performance for instance retrieval, and they outperformthe traditional hand-crafted image features. However, most of existing CNN-based featuresare proposed to describe the entire images, and thus they are less robust to backgroundclutter. This paper proposes a region of interest (RoI)-based deep convolutionalrepresentation for instance retrieval. It first detects the region of interests (RoIs) from animage, and then extracts a set of RoI-based CNN features from the fully-connected layerof CNN. The proposed RoI-based CNN feature describes the patterns of the detected RoIs,so that the visual matching can be implemented at image region-level to effectively identifytarget objects from cluttered backgrounds. Moreover, we test the performance of theproposed RoI-based CNN feature, when it is extracted from different convolutional layersor fully-connected layers. Also, we compare the performance of RoI-based CNN featurewith those of the state-of-the-art CNN features on two instance retrieval benchmarks.Experimental results show that the proposed RoI-based CNN feature provides superiorperformance than the state-of-the-art CNN features for in-stance retrieval.展开更多
Existing orthogonal space-time block coding(OSTBC)schemes for backscatter communication systems cannot achieve a full transmission code rate when the tag is equipped with more than two antennas.In this paper,we propos...Existing orthogonal space-time block coding(OSTBC)schemes for backscatter communication systems cannot achieve a full transmission code rate when the tag is equipped with more than two antennas.In this paper,we propose a quasi-orthogonal spacetime block code(QOSTBC)that can achieve a full transmission code rate for backscatter communication systems with a four-antenna tag and then extend the scheme to support tags with 2i antennas.Specifically,we first present the system model for the backscatter system.Next,we propose the QOSTBC scheme to encode the tag signals.Then,we provide the corresponding maximum likelihood detection algorithms to recover the tag signals.Finally,simulation results are provided to demonstrate that our proposed QOSTBC scheme and the detection algorithm can achieve a better transmission code rate or symbol error rate performance for backscatter communication systems compared with benchmark schemes.展开更多
Along with the rapid development of informatization, people habitually rely on electronic devices. For the convenience and efficiency provided by various devices, people could dispose almost everything by their phones...Along with the rapid development of informatization, people habitually rely on electronic devices. For the convenience and efficiency provided by various devices, people could dispose almost everything by their phones and PC. In this respect, the security of the electronic devices that people use in daily life becomes much more important. In this area, exerts has tried many ways to keep data and uses safe from attacks. This paper has designed a Voice Based Biometric Security System, which is able to reinforce the security level of the target device. With its help, the electronic devices will be more security.展开更多
A continuous-time 7th-order Butterworth Gm-C low pass filter （LPF） with on-chip automatic tuning circuit has been implemented for a direct conversion DBS tuner in 0.35 μm SiGe BiCMOS technology. The filter＇s -3 dB...A continuous-time 7th-order Butterworth Gm-C low pass filter （LPF） with on-chip automatic tuning circuit has been implemented for a direct conversion DBS tuner in 0.35 μm SiGe BiCMOS technology. The filter＇s -3 dB cutoff frequency f0 can be tuned from 4 to 40 MHz. A novel on-chip automatic tuning scheme has been successfully realized to tune and Iock the filter＇s cutoff frequency. Measurement results show that the filter has -0.5 dB passband gain, ＋/- 5% bandwidth accuracy, 30 nV/Hz1/2 input referred noise, -3 dBVrms passband IIP3, and 27 dBVrms stopband IIP3. The I/Q LPFs with the tuning circuit draw 13 mA （with f0 = 20 MHz） from 5 V supply, and occupy 0.5 mm^2.展开更多
Fault currents emanating from inverter-based resources(IBRs)are controlled to follow specific references to support the power grid during faults.However,these fault currents differ from the typical fault currents fed ...Fault currents emanating from inverter-based resources(IBRs)are controlled to follow specific references to support the power grid during faults.However,these fault currents differ from the typical fault currents fed by synchronous generators,resulting in an improper operation of conventional phase selection methods(PSMs).In this paper,the relative angles between sequence voltages measured at the relay location are determined analytically in two stages:(1)a short-circuit analysis is performed at the fault location to determine the relative angles between sequence voltages;and(2)an analysis of the impact of transmission line on the phase difference between the sequence voltages of relay and fault is conducted for different IBR controllers.Consequently,new PSM zones based on relative angles between sequence voltages are devised to facilitate accurate PSM regardless of the fault currents,resistances,or locations of IBR.Comprehensive time-domain simulations confirm the accuracy of the proposed PSM with different fault locations,resistances,types,and currents.展开更多
基金supported by the National Natural Science Foundation ofChina under Grant 61602253, U1836208, U1536206, U1836110, 61672294, in part by theNational Key R&D Program of China under Grant 2018YFB1003205, in part by the PriorityAcademic Program Development of Jiangsu Higher Education Institutions (PAPD) fund, inpart by the Collaborative Innovation Center of Atmospheric Environment and EquipmentTechnology (CICAEET) fund, China, and in part by MOST under contracts 108-2634-F-259-001- through Pervasive Artificial Intelligence Research (PAIR) Labs, Taiwan.
文摘Recently, image representations derived by convolutional neural networks(CNN) have achieved promising performance for instance retrieval, and they outperformthe traditional hand-crafted image features. However, most of existing CNN-based featuresare proposed to describe the entire images, and thus they are less robust to backgroundclutter. This paper proposes a region of interest (RoI)-based deep convolutionalrepresentation for instance retrieval. It first detects the region of interests (RoIs) from animage, and then extracts a set of RoI-based CNN features from the fully-connected layerof CNN. The proposed RoI-based CNN feature describes the patterns of the detected RoIs,so that the visual matching can be implemented at image region-level to effectively identifytarget objects from cluttered backgrounds. Moreover, we test the performance of theproposed RoI-based CNN feature, when it is extracted from different convolutional layersor fully-connected layers. Also, we compare the performance of RoI-based CNN featurewith those of the state-of-the-art CNN features on two instance retrieval benchmarks.Experimental results show that the proposed RoI-based CNN feature provides superiorperformance than the state-of-the-art CNN features for in-stance retrieval.
基金supported by Beijing Municipal Natural Science Foundation(L222002)the Natural Science Foundation of China(U22B2004).
文摘Existing orthogonal space-time block coding(OSTBC)schemes for backscatter communication systems cannot achieve a full transmission code rate when the tag is equipped with more than two antennas.In this paper,we propose a quasi-orthogonal spacetime block code(QOSTBC)that can achieve a full transmission code rate for backscatter communication systems with a four-antenna tag and then extend the scheme to support tags with 2i antennas.Specifically,we first present the system model for the backscatter system.Next,we propose the QOSTBC scheme to encode the tag signals.Then,we provide the corresponding maximum likelihood detection algorithms to recover the tag signals.Finally,simulation results are provided to demonstrate that our proposed QOSTBC scheme and the detection algorithm can achieve a better transmission code rate or symbol error rate performance for backscatter communication systems compared with benchmark schemes.
文摘Along with the rapid development of informatization, people habitually rely on electronic devices. For the convenience and efficiency provided by various devices, people could dispose almost everything by their phones and PC. In this respect, the security of the electronic devices that people use in daily life becomes much more important. In this area, exerts has tried many ways to keep data and uses safe from attacks. This paper has designed a Voice Based Biometric Security System, which is able to reinforce the security level of the target device. With its help, the electronic devices will be more security.
文摘A continuous-time 7th-order Butterworth Gm-C low pass filter （LPF） with on-chip automatic tuning circuit has been implemented for a direct conversion DBS tuner in 0.35 μm SiGe BiCMOS technology. The filter＇s -3 dB cutoff frequency f0 can be tuned from 4 to 40 MHz. A novel on-chip automatic tuning scheme has been successfully realized to tune and Iock the filter＇s cutoff frequency. Measurement results show that the filter has -0.5 dB passband gain, ＋/- 5% bandwidth accuracy, 30 nV/Hz1/2 input referred noise, -3 dBVrms passband IIP3, and 27 dBVrms stopband IIP3. The I/Q LPFs with the tuning circuit draw 13 mA （with f0 = 20 MHz） from 5 V supply, and occupy 0.5 mm^2.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)(No.RGPIN-2023-0368)Qatar University(No.QUCG-CENG-24/25-485)。
文摘Fault currents emanating from inverter-based resources(IBRs)are controlled to follow specific references to support the power grid during faults.However,these fault currents differ from the typical fault currents fed by synchronous generators,resulting in an improper operation of conventional phase selection methods(PSMs).In this paper,the relative angles between sequence voltages measured at the relay location are determined analytically in two stages:(1)a short-circuit analysis is performed at the fault location to determine the relative angles between sequence voltages;and(2)an analysis of the impact of transmission line on the phase difference between the sequence voltages of relay and fault is conducted for different IBR controllers.Consequently,new PSM zones based on relative angles between sequence voltages are devised to facilitate accurate PSM regardless of the fault currents,resistances,or locations of IBR.Comprehensive time-domain simulations confirm the accuracy of the proposed PSM with different fault locations,resistances,types,and currents.
