Micro-Opto-Electro-Mechanical Systems(MOEMS)accelerometer is a new type of accelerometer which combines the merits of optical measurement and Micro-Electro-Mechanical Systems(MEMS)to enable high precision,small volume...Micro-Opto-Electro-Mechanical Systems(MOEMS)accelerometer is a new type of accelerometer which combines the merits of optical measurement and Micro-Electro-Mechanical Systems(MEMS)to enable high precision,small volume and anti-electromagnetic disturbance measurement of acceleration.In recent years,with the in-depth research and development of MOEMS accelerometers,the community is flourishing with the possible applications in seismic monitoring,inertial navigation,aerospace and other industrial and military fields.There have been a variety of schemes of MOEMS accelerometers,whereas the performances differ greatly due to different measurement principles and corresponding application requirements.This paper aims to address the pressing issue of the current lack of systematic review of MOEMS accelerometers.According to the optical measurement principle,we divide the MOEMS accelerometers into three categories:the geometric optics based,the wave optics based,and the new optomechanical accelerometers.Regarding the most widely studied category,the wave optics based accelerometers are further divided into four sub-categories,which is based on grating interferometric cavity,Fiber Bragg Grating(FBG),Fabry-Perot cavity,and photonic crystal,respectively.Following a brief introduction to the measurement principles,the typical performances,advantages and disadvantages as well as the potential application scenarios of all kinds of MOEMS accelerometers are discussed on the basis of typical demonstrations.This paper also presents the status and development tendency of MOEMS accelerometers to meet the ever-increasing demand for high-precision acceleration measurement.展开更多
This paper presents a novel approach of M-ary baseband pulse amplitude modulated signal processing via a parameter-optimized nonlinear dynamic system. This nonlinear system usually shows the phenomenon of stochastic r...This paper presents a novel approach of M-ary baseband pulse amplitude modulated signal processing via a parameter-optimized nonlinear dynamic system. This nonlinear system usually shows the phenomenon of stochastic resonance by adding noise. To thoroughly discuss the signal processing performance of the nonlinear system, we tune the system parameters to obtain a nonlinear detector with optimal performance. For characterizing the output of the nonlinear system, the derivation of the probability of detection error is given by the system response speed and the probability density function of the nonlinear system output. By varying the noise intensity with fixed system parameters, the phenomenon of stochastic resonance is shown and by tuning the system parameters with fixed noise, the probability of detection error is minimized and the nonlinear system is optimized. The detection performance of the two cases is compared with the theoretical probability of detection error, which is validated by numerical simulation.展开更多
In this paper, we discuss the effects of error feedback on the output of a nonlinear bistable system with stochastic resonance. The bit error rate is employed to quantify the performance of the system. The theoretical...In this paper, we discuss the effects of error feedback on the output of a nonlinear bistable system with stochastic resonance. The bit error rate is employed to quantify the performance of the system. The theoretical analysis and the numerical simulation are presented. By investigating the performances of the nonlinear systems with different strengths of error feedback, we argue that the presented system may provide guidance for practical nonlinear signal processing.展开更多
In this paper,an effective target locating approach based on the fingerprint fusion posi-tioning(FFP)method is proposed which integrates the time-difference of arrival(TDOA)and the received signal strength according t...In this paper,an effective target locating approach based on the fingerprint fusion posi-tioning(FFP)method is proposed which integrates the time-difference of arrival(TDOA)and the received signal strength according to the statistical variance of target position in the stationary 3D scenarios.The FFP method fuses the pedestrian dead reckoning(PDR)estimation to solve the moving target localization problem.We also introduce auxiliary parameters to estimate the target motion state.Subsequently,we can locate the static pedestrians and track the the moving target.For the case study,eight access stationary points are placed on a bookshelf and hypermarket;one target node is moving inside hypermarkets in 2D and 3D scenarios or stationary on the bookshelf.We compare the performance of our proposed method with existing localization algorithms such as k-nearest neighbor,weighted k-nearest neighbor,pure TDOA and fingerprinting combining Bayesian frameworks including the extended Kalman filter,unscented Kalman filter and particle fil-ter(PF).The proposed approach outperforms obviously the counterpart methodologies in terms of the root mean square error and the cumulative distribution function of localization errors,espe-cially in the 3D scenarios.Simulation results corroborate the effectiveness of our proposed approach.展开更多
In this paper, the effects of a bistable potential function U（x） = -ax2/2＋b｜x＋｜2y/（2y） on stochastic resonance （SR） is discussed. We investigate the effects of index y on the performance of the SR system wit...In this paper, the effects of a bistable potential function U（x） = -ax2/2＋b｜x＋｜2y/（2y） on stochastic resonance （SR） is discussed. We investigate the effects of index y on the performance of the SR system with fixed parameters a and b, and with fixed potential barriers, respectively. To measure the performance of the SR system in the presence of an aperiodic input, the bit error rate is employed, as is commonly used in binary communications. The numerical simulations strongly support the theoretical results. The goal of this investigation is to explore the effects of the shape of potential functions on SR and give a guidance of nonlinear systems in the application of information processing.展开更多
Optical cavity has long been critical for a variety of applications ranging from precise measurement to spectral analysis.A number of theories and methods have been successful in describing the optical response of a s...Optical cavity has long been critical for a variety of applications ranging from precise measurement to spectral analysis.A number of theories and methods have been successful in describing the optical response of a stratified optical cavity,while the inverse problem,especially the inverse design of a displacement sensitive cavity,remains a significant challenge due to the cost of computation and comprehensive performance requirements.This paper reports a novel inverse design methodology combining the characteristic matrix method,mixed-discrete variables optimization algorithm,and Monte Carlo method-based tolerance analysis.The material characteristics are indexed to enable the mixed-discrete variables optimization,which yields considerable speed and efficiency improvements.This method allows arbitrary response adjustment with technical feasibility and gives a glimpse into the analytical characterization of the optical response.Two entirely different light-displacement responses,including an asymmetric sawtooth-like response and a highly symmetric response,are dug out and experimentally achieved,which fully confirms the validity of the method.The compact Fabry-Perot cavities have a good balance between performance and feasibility,making them promising candidates for displacement transducers.More importantly,the proposed inverse design paves the way for a universal design of optical cavities,or even nanophotonic devices.展开更多
As the progress of 3D rendering technology and the changes of market demand, the 3D application has been widely used and reached as far as education, entertainment, medical treatment, city planning, military training ...As the progress of 3D rendering technology and the changes of market demand, the 3D application has been widely used and reached as far as education, entertainment, medical treatment, city planning, military training and so on. Its trend is gradually changed from client to web, and so many people start to research the 3D graphics engine technology on the web. WebGL and HTML5 rise in recent years and WebGL solves two problems of interactive 3D application on the web perfectly. Firstly, it implements the interactive 3D web application by JavaScript without any browser plug-in components. Secondly, it makes graphics rendering using the underlying graphics hardware, which is united, standard and cross-platform OpenGL interface. However, it is very difficult for 3D application web programmer to understand multifarious details. Therefore, a 3D engine based on WebGL comes into being. The paper consults the existing 3D engine design idea, architecture and implementation experience, and designs a 3D graphics engine based on WebGL and Typescript.展开更多
Constituted by BCH component codes and its ordered statistics decoding(OSD),the successive cancellation list(SCL)decoding of U-UV structural codes can provide competent error-correction performance in the short-to-med...Constituted by BCH component codes and its ordered statistics decoding(OSD),the successive cancellation list(SCL)decoding of U-UV structural codes can provide competent error-correction performance in the short-to-medium length regime.However,this list decoding complexity becomes formidable as the decoding output list size increases.This is primarily incurred by the OSD.Addressing this challenge,this paper proposes the low complexity SCL decoding through reducing the complexity of component code decoding,and pruning the redundant SCL decoding paths.For the former,an efficient skipping rule is introduced for the OSD so that the higher order decoding can be skipped when they are not possible to provide a more likely codeword candidate.It is further extended to the OSD variant,the box-andmatch algorithm(BMA),in facilitating the component code decoding.Moreover,through estimating the correlation distance lower bounds(CDLBs)of the component code decoding outputs,a path pruning(PP)-SCL decoding is proposed to further facilitate the decoding of U-UV codes.In particular,its integration with the improved OSD and BMA is discussed.Simulation results show that significant complexity reduction can be achieved.Consequently,the U-UV codes can outperform the cyclic redundancy check(CRC)-polar codes with a similar decoding complexity.展开更多
There are critical transition phenomena during the progression of many diseases.Such critical transitions are usually accompanied by catastrophic disease deterioration,and their prediction is of significant importance...There are critical transition phenomena during the progression of many diseases.Such critical transitions are usually accompanied by catastrophic disease deterioration,and their prediction is of significant importance for disease prevention and treatment.However,predicting disease deterioration solely based on a single sample is a difficult problem.In this study,we presented the network information gain(NIG)method,for predicting the critical transitions or disease state based on network flow entropy from omics data of each individual.NIG can not only efficiently predict disease deteriorations but also detect their dynamic network biomarkers on an individual basis and further identify potential therapeutic targets.The numerical simulation demonstrates the effectiveness of NIG.Moreover,our method was validated by successfully predicting disease deteriorations and identifying their potential therapeutic targets from four real omics datasets,i.e.,an influenza dataset and three cancer datasets.展开更多
This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision te...This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision techniques, the translation is only known up to a scale factor, and a single scale factor is assumed for the whole sequence of images if only one camera is used. If an extra camera is available, stereo vision based reconstruction can be obtained by binocular views. If the baseline of the stereo setup is known, the scale factor problem is solved. We found that direct application of classical bundle adjustment on the constraints inherent between the binocular views has not been tested. Our method incorporated this constraint into the conventional bundle adjustment method. This special binocular bundle adjustment has been performed on image sequences similar to planet terrain circumstances. Experimental results show that our special method enhances not only the localization accuracy, but also the terrain mapping quality.展开更多
Cooperative spectrum sensing in cog- nitive radio is investigated to improve the det- ection performance of Primary User （PU）. Meanwhile, cluster-based hierarchical coop- eration is introduced for reducing the overh...Cooperative spectrum sensing in cog- nitive radio is investigated to improve the det- ection performance of Primary User （PU）. Meanwhile, cluster-based hierarchical coop- eration is introduced for reducing the overhead as well as maintaining a certain level of sens- ing performance. However, in existing hierar- chically cooperative spectrum sensing algo- rithms, the robustness problem of the system is seldom considered. In this paper, we pro- pose a reputation-based hierarchically coop- erative spectrum sensing scheme in Cognitive Radio Networks （CRNs）. Before spectrum sensing, clusters are grouped based on the location correlation coefficients of Secondary Users （SUs）. In the proposed scheme, there are two levels of cooperation, the first one is performed within a cluster and the second one is carried out among clusters. With the reputa- tion mechanism and modified MAJORITY rule in the second level cooperation, the pro- posed scheme can not only relieve the influ- ence of the shadowing, but also eliminate the impact of the PU emulation attack on a rela- tively large scale. Simulation results show that, in the scenarios with deep-shadowing or mul- tiple attacked SUs, our proposed scheme ach- ieves a better tradeoff between the system robustness and the energy saving compared with those conventionally cooperative sensing schemes.展开更多
A novel Er:YAG laser system operating at 1645 nm with high pulse-repetition-frequency(PRF)of kHz level is demonstrated.A ring cavity with double gain medium end-pumped by two fiber lasers is utilized to obtain high pu...A novel Er:YAG laser system operating at 1645 nm with high pulse-repetition-frequency(PRF)of kHz level is demonstrated.A ring cavity with double gain medium end-pumped by two fiber lasers is utilized to obtain high pulse energy.A novel‘triple-reflection’configuration on a piezoelectric actuator(PZT)is adopted to achieve high-repetition-rate at 3-kHz operation with the ramp-fire locking method.Single frequency pulses with maximum average power of 18.3 W at 3 kHz are obtained,and the pulse duration time is 318 ns.The full line width at half maximum(FWHM)of the pulses measured by the heterodyne technique is 1.71 MHz at 3 kHz.To the best of our knowledge,this is the highest PRF single-frequency laser pulses achieved based Er:YAG gain medium.展开更多
Steganalysis is a technique used for detecting the existence of secret information embedded into cover media such as images and videos.Currently,with the higher speed of the Internet,videos have become a kind of main ...Steganalysis is a technique used for detecting the existence of secret information embedded into cover media such as images and videos.Currently,with the higher speed of the Internet,videos have become a kind of main methods for transferring information.The latest video coding standard High Efficiency Video Coding(HEVC)shows better coding performance compared with the H.264/AVC standard published in the previous time.Therefore,since the HEVC was published,HEVC videos have been widely used as carriers of hidden information.In this paper,a steganalysis algorithm is proposed to detect the latest HEVC video steganography method which is based on the modification of Prediction Units(PU)partition modes.To detect the embedded data,All the PU partition modes are extracted from P pictures,and the probability of each PU partition mode in cover videos and stego videos is adopted as the classification feature.Furthermore,feature optimization is applied,that the 25-dimensional steganalysis feature has been reduced to the 3-dimensional feature.Then the Support Vector Machine(SVM)is used to identify stego videos.It is demonstrated in experimental results that the proposed steganalysis algorithm can effectively detect the stego videos,and much higher classification accuracy has been achieved compared with state-of-the-art work.展开更多
In recent years,binary image steganography has developed so rapidly that the research of binary image steganalysis becomes more important for information security.In most state-of-the-art binary image steganographic s...In recent years,binary image steganography has developed so rapidly that the research of binary image steganalysis becomes more important for information security.In most state-of-the-art binary image steganographic schemes,they always find out the flippable pixels to minimize the embedding distortions.For this reason,the stego images generated by the previous schemes maintain visual quality and it is hard for steganalyzer to capture the embedding trace in spacial domain.However,the distortion maps can be calculated for cover and stego images and the difference between them is significant.In this paper,a novel binary image steganalytic scheme is proposed,which is based on distortion level co-occurrence matrix.The proposed scheme first generates the corresponding distortion maps for cover and stego images.Then the co-occurrence matrix is constructed on the distortion level maps to represent the features of cover and stego images.Finally,support vector machine,based on the gaussian kernel,is used to classify the features.Compared with the prior steganalytic methods,experimental results demonstrate that the proposed scheme can effectively detect stego images.展开更多
Robustness is one of the most important requirements of digital watermarking for many applications. Spread-spectrum based methods are not effective enough to ensure their robustness. By modeling digital watermarking a...Robustness is one of the most important requirements of digital watermarking for many applications. Spread-spectrum based methods are not effective enough to ensure their robustness. By modeling digital watermarking as digital communications, several researchers proposed using error correcting coding (ECC) to improve robustness. However, an important fact that has long been neglected is that due to the imperceptibility requirement, the redundancy introduced by ECC will lead to a decrease of the magnitude of watermark signal. Therefore, a problem arises naturally:Could the usage of ECC effectively improve the robustness of watermarking? This paper addresses this problem from the perspectives of both theoretical analysis and experimental investigation. Our investigation shows that ECG cannot effectively improve the robustness of watermarking against a great majority of various attacks except for cropping and jitter attacks. Hence, ECC should not be considered as a universal measure that can be employed to enhance robustness of watermarking.展开更多
An adaptive pipelining scheme for H.264/AVC context-based adaptive binary arithmetic coding(CABAC) decoder for high definition(HD) applications is proposed to solve data hazard problems coming from the data dependenci...An adaptive pipelining scheme for H.264/AVC context-based adaptive binary arithmetic coding(CABAC) decoder for high definition(HD) applications is proposed to solve data hazard problems coming from the data dependencies in CABAC decoding process.An efficiency model of CABAC decoding pipeline is derived according to the analysis of a common pipeline.Based on that,several adaptive strategies are provided.The pipelining scheme with these strategies can be adaptive to different types of syntax elements(SEs) and the pipeline will not stall during decoding process when these strategies are adopted.In addition,the decoder proposed can fully support H.264/AVC high4:2:2 profile and the experimental results show that the efficiency of decoder is much higher than other architectures with one engine.Taking both performance and cost into consideration,our design makes a good tradeoff compared with other work and it is sufficient for HD real-time decoding.展开更多
As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,...As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,e.g.,weather conditions,evaporation ducting,and ship rocking caused by waves.To ensure the data transmission reliability,the block Markov superposition transmission(BMST)codes,which are easily configurable and have predictable performance,are applied in this study.Meanwhile,the physical-layer network coding(PNC)scheme with spatial modulation(SM)is adopted to improve the spectrum utilization.For the BMST-SMPNC system,we propose an iterative algorithm,which utilizes the channel observations and the a priori information from BMST decoder,to compute the soft information corresponding to the XORed bits constructed by the relay node.The results indicate that the proposed scheme outperforms the convolutional coded SM-PNC over fast-fading Rician channels.Especially,the performance can be easily improved in high spatial correlation maritime channel by increasing the memory m.展开更多
Proxy signatures have been used to enable the transfer of digital signing power within some context and ring signatures can be used to provide the anonymity of a signer. By combining the functionalities of proxy signa...Proxy signatures have been used to enable the transfer of digital signing power within some context and ring signatures can be used to provide the anonymity of a signer. By combining the functionalities of proxy signatures and ring signatures, this paper introduces a new concept, named ring proxy signature, which is a proxy signature generated by an anonymous member from a set of potential signers. The paper also constructs the first concrete ring proxy signature scheme based on the provably secure Schnorr's signatures and two ID-based ring proxy signature schemes. The security analysis is provided as well.展开更多
In recent years,with the rapid development of deep learning technologies,some neural network models have been applied to generate fake media.DeepFakes,a deep learning based forgery technology,can tamper with the face ...In recent years,with the rapid development of deep learning technologies,some neural network models have been applied to generate fake media.DeepFakes,a deep learning based forgery technology,can tamper with the face easily and generate fake videos that are difficult to be distinguished by human eyes.The spread of face manipulation videos is very easy to bring fake information.Therefore,it is important to develop effective detection methods to verify the authenticity of the videos.Due to that it is still challenging for current forgery technologies to generate all facial details and the blending operations are used in the forgery process,the texture details of the fake face are insufficient.Therefore,in this paper,a new method is proposed to detect DeepFake videos.Firstly,the texture features are constructed,which are based on the gradient domain,standard deviation,gray level co-occurrence matrix and wavelet transform of the face region.Then,the features are processed by the feature selection method to form a discriminant feature vector,which is finally employed to SVM for classification at the frame level.The experimental results on the mainstream DeepFake datasets demonstrate that the proposed method can achieve ideal performance,proving the effectiveness of the proposed method for DeepFake videos detection.展开更多
The estimation of image resampling factors is an important problem in image forensics.Among all the resampling factor estimation methods,spectrumbased methods are one of the most widely used methods and have attracted...The estimation of image resampling factors is an important problem in image forensics.Among all the resampling factor estimation methods,spectrumbased methods are one of the most widely used methods and have attracted a lot of research interest.However,because of inherent ambiguity,spectrum-based methods fail to discriminate upscale and downscale operations without any prior information.In general,the application of resampling leaves detectable traces in both spatial domain and frequency domain of a resampled image.Firstly,the resampling process will introduce correlations between neighboring pixels.In this case,a set of periodic pixels that are correlated to their neighbors can be found in a resampled image.Secondly,the resampled image has distinct and strong peaks on spectrum while the spectrum of original image has no clear peaks.Hence,in this paper,we propose a dual-stream convolutional neural network for image resampling factors estimation.One of the two streams is gray stream whose purpose is to extract resampling traces features directly from the rescaled images.The other is frequency stream that discovers the differences of spectrum between rescaled and original images.The features from two streams are then fused to construct a feature representation including the resampling traces left in spatial and frequency domain,which is later fed into softmax layer for resampling factor estimation.Experimental results show that the proposed method is effective on resampling factor estimation and outperforms some CNN-based methods.展开更多
基金supports from National Natural Science Foundation of China(No.62004166)Fundamental Research Funds for the Central Universities(No.31020190QD027)+2 种基金Natural Science Basic Research Program of Shaanxi(Program No.2020JQ-199)China National Postdoctoral Program for Innovative Talents(No.BX20200279)Key Research and Development Program of Shaanxi Province(2020GXLH-Z-027,2020ZDLGY04-08).
文摘Micro-Opto-Electro-Mechanical Systems(MOEMS)accelerometer is a new type of accelerometer which combines the merits of optical measurement and Micro-Electro-Mechanical Systems(MEMS)to enable high precision,small volume and anti-electromagnetic disturbance measurement of acceleration.In recent years,with the in-depth research and development of MOEMS accelerometers,the community is flourishing with the possible applications in seismic monitoring,inertial navigation,aerospace and other industrial and military fields.There have been a variety of schemes of MOEMS accelerometers,whereas the performances differ greatly due to different measurement principles and corresponding application requirements.This paper aims to address the pressing issue of the current lack of systematic review of MOEMS accelerometers.According to the optical measurement principle,we divide the MOEMS accelerometers into three categories:the geometric optics based,the wave optics based,and the new optomechanical accelerometers.Regarding the most widely studied category,the wave optics based accelerometers are further divided into four sub-categories,which is based on grating interferometric cavity,Fiber Bragg Grating(FBG),Fabry-Perot cavity,and photonic crystal,respectively.Following a brief introduction to the measurement principles,the typical performances,advantages and disadvantages as well as the potential application scenarios of all kinds of MOEMS accelerometers are discussed on the basis of typical demonstrations.This paper also presents the status and development tendency of MOEMS accelerometers to meet the ever-increasing demand for high-precision acceleration measurement.
基金Project supported by the National Natural Science Foundation of China (Grant No 60702022)
文摘This paper presents a novel approach of M-ary baseband pulse amplitude modulated signal processing via a parameter-optimized nonlinear dynamic system. This nonlinear system usually shows the phenomenon of stochastic resonance by adding noise. To thoroughly discuss the signal processing performance of the nonlinear system, we tune the system parameters to obtain a nonlinear detector with optimal performance. For characterizing the output of the nonlinear system, the derivation of the probability of detection error is given by the system response speed and the probability density function of the nonlinear system output. By varying the noise intensity with fixed system parameters, the phenomenon of stochastic resonance is shown and by tuning the system parameters with fixed noise, the probability of detection error is minimized and the nonlinear system is optimized. The detection performance of the two cases is compared with the theoretical probability of detection error, which is validated by numerical simulation.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61171147 and 60702022)
文摘In this paper, we discuss the effects of error feedback on the output of a nonlinear bistable system with stochastic resonance. The bit error rate is employed to quantify the performance of the system. The theoretical analysis and the numerical simulation are presented. By investigating the performances of the nonlinear systems with different strengths of error feedback, we argue that the presented system may provide guidance for practical nonlinear signal processing.
基金partially supported by the National Natural Science Foun-dation of China(No.62071389).
文摘In this paper,an effective target locating approach based on the fingerprint fusion posi-tioning(FFP)method is proposed which integrates the time-difference of arrival(TDOA)and the received signal strength according to the statistical variance of target position in the stationary 3D scenarios.The FFP method fuses the pedestrian dead reckoning(PDR)estimation to solve the moving target localization problem.We also introduce auxiliary parameters to estimate the target motion state.Subsequently,we can locate the static pedestrians and track the the moving target.For the case study,eight access stationary points are placed on a bookshelf and hypermarket;one target node is moving inside hypermarkets in 2D and 3D scenarios or stationary on the bookshelf.We compare the performance of our proposed method with existing localization algorithms such as k-nearest neighbor,weighted k-nearest neighbor,pure TDOA and fingerprinting combining Bayesian frameworks including the extended Kalman filter,unscented Kalman filter and particle fil-ter(PF).The proposed approach outperforms obviously the counterpart methodologies in terms of the root mean square error and the cumulative distribution function of localization errors,espe-cially in the 3D scenarios.Simulation results corroborate the effectiveness of our proposed approach.
基金Project supported by the National Natural Science Foundation of China(Grant No.60702022)
文摘In this paper, the effects of a bistable potential function U（x） = -ax2/2＋b｜x＋｜2y/（2y） on stochastic resonance （SR） is discussed. We investigate the effects of index y on the performance of the SR system with fixed parameters a and b, and with fixed potential barriers, respectively. To measure the performance of the SR system in the presence of an aperiodic input, the bit error rate is employed, as is commonly used in binary communications. The numerical simulations strongly support the theoretical results. The goal of this investigation is to explore the effects of the shape of potential functions on SR and give a guidance of nonlinear systems in the application of information processing.
基金We are grateful for financial supports from National Natural Science Foundation of China(62004166)Natural Science Foundation of Ningbo(202003N4062)+2 种基金National Postdoctoral Program for Innovative Talents(BX20200279)Natural Science Basic Research Program of Shaanxi Province(2020JQ-199)Fundamental Research Funds for the Central Universities(31020190QD027).
文摘Optical cavity has long been critical for a variety of applications ranging from precise measurement to spectral analysis.A number of theories and methods have been successful in describing the optical response of a stratified optical cavity,while the inverse problem,especially the inverse design of a displacement sensitive cavity,remains a significant challenge due to the cost of computation and comprehensive performance requirements.This paper reports a novel inverse design methodology combining the characteristic matrix method,mixed-discrete variables optimization algorithm,and Monte Carlo method-based tolerance analysis.The material characteristics are indexed to enable the mixed-discrete variables optimization,which yields considerable speed and efficiency improvements.This method allows arbitrary response adjustment with technical feasibility and gives a glimpse into the analytical characterization of the optical response.Two entirely different light-displacement responses,including an asymmetric sawtooth-like response and a highly symmetric response,are dug out and experimentally achieved,which fully confirms the validity of the method.The compact Fabry-Perot cavities have a good balance between performance and feasibility,making them promising candidates for displacement transducers.More importantly,the proposed inverse design paves the way for a universal design of optical cavities,or even nanophotonic devices.
文摘As the progress of 3D rendering technology and the changes of market demand, the 3D application has been widely used and reached as far as education, entertainment, medical treatment, city planning, military training and so on. Its trend is gradually changed from client to web, and so many people start to research the 3D graphics engine technology on the web. WebGL and HTML5 rise in recent years and WebGL solves two problems of interactive 3D application on the web perfectly. Firstly, it implements the interactive 3D web application by JavaScript without any browser plug-in components. Secondly, it makes graphics rendering using the underlying graphics hardware, which is united, standard and cross-platform OpenGL interface. However, it is very difficult for 3D application web programmer to understand multifarious details. Therefore, a 3D engine based on WebGL comes into being. The paper consults the existing 3D engine design idea, architecture and implementation experience, and designs a 3D graphics engine based on WebGL and Typescript.
基金supported by the National Natural Science Foundation of China(NSFC)with project ID 62071498the Guangdong National Science Foundation(GDNSF)with project ID 2024A1515010213.
文摘Constituted by BCH component codes and its ordered statistics decoding(OSD),the successive cancellation list(SCL)decoding of U-UV structural codes can provide competent error-correction performance in the short-to-medium length regime.However,this list decoding complexity becomes formidable as the decoding output list size increases.This is primarily incurred by the OSD.Addressing this challenge,this paper proposes the low complexity SCL decoding through reducing the complexity of component code decoding,and pruning the redundant SCL decoding paths.For the former,an efficient skipping rule is introduced for the OSD so that the higher order decoding can be skipped when they are not possible to provide a more likely codeword candidate.It is further extended to the OSD variant,the box-andmatch algorithm(BMA),in facilitating the component code decoding.Moreover,through estimating the correlation distance lower bounds(CDLBs)of the component code decoding outputs,a path pruning(PP)-SCL decoding is proposed to further facilitate the decoding of U-UV codes.In particular,its integration with the improved OSD and BMA is discussed.Simulation results show that significant complexity reduction can be achieved.Consequently,the U-UV codes can outperform the cyclic redundancy check(CRC)-polar codes with a similar decoding complexity.
基金supported by the National Natural Science Foundation of China(31930022,12131020,T2341007,T2350003)National Key R&D Program of China(2022YFA1004800)+3 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB38040400)Special Fund for Science and Technology Innovation Strategy of Guangdong Province(2021B0909050004,2021B0909060002)Key-Area Research and Development Program of Guangdong Province(2021B0909060002)MajorKey Project of PCL(PCL2021A12),and JST Moonshot R&D(JPMJMS2021).
文摘There are critical transition phenomena during the progression of many diseases.Such critical transitions are usually accompanied by catastrophic disease deterioration,and their prediction is of significant importance for disease prevention and treatment.However,predicting disease deterioration solely based on a single sample is a difficult problem.In this study,we presented the network information gain(NIG)method,for predicting the critical transitions or disease state based on network flow entropy from omics data of each individual.NIG can not only efficiently predict disease deteriorations but also detect their dynamic network biomarkers on an individual basis and further identify potential therapeutic targets.The numerical simulation demonstrates the effectiveness of NIG.Moreover,our method was validated by successfully predicting disease deteriorations and identifying their potential therapeutic targets from four real omics datasets,i.e.,an influenza dataset and three cancer datasets.
基金the National Natural Science Foundation of China (Nos. 60505017 and 60534070)the Science Planning Project of Zhejiang Province, China (No. 2005C14008)
文摘This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision techniques, the translation is only known up to a scale factor, and a single scale factor is assumed for the whole sequence of images if only one camera is used. If an extra camera is available, stereo vision based reconstruction can be obtained by binocular views. If the baseline of the stereo setup is known, the scale factor problem is solved. We found that direct application of classical bundle adjustment on the constraints inherent between the binocular views has not been tested. Our method incorporated this constraint into the conventional bundle adjustment method. This special binocular bundle adjustment has been performed on image sequences similar to planet terrain circumstances. Experimental results show that our special method enhances not only the localization accuracy, but also the terrain mapping quality.
基金ACKNOWLEDGEMENT This work was partially supported by the Na- tional Natural Science Foundation of China under Grant No. 61071127 and the Science and Technology Department of Zhejiang Pro- vince under Grants No. 2012C01036-1, No. 2011R10035.
文摘Cooperative spectrum sensing in cog- nitive radio is investigated to improve the det- ection performance of Primary User （PU）. Meanwhile, cluster-based hierarchical coop- eration is introduced for reducing the overhead as well as maintaining a certain level of sens- ing performance. However, in existing hierar- chically cooperative spectrum sensing algo- rithms, the robustness problem of the system is seldom considered. In this paper, we pro- pose a reputation-based hierarchically coop- erative spectrum sensing scheme in Cognitive Radio Networks （CRNs）. Before spectrum sensing, clusters are grouped based on the location correlation coefficients of Secondary Users （SUs）. In the proposed scheme, there are two levels of cooperation, the first one is performed within a cluster and the second one is carried out among clusters. With the reputa- tion mechanism and modified MAJORITY rule in the second level cooperation, the pro- posed scheme can not only relieve the influ- ence of the shadowing, but also eliminate the impact of the PU emulation attack on a rela- tively large scale. Simulation results show that, in the scenarios with deep-shadowing or mul- tiple attacked SUs, our proposed scheme ach- ieves a better tradeoff between the system robustness and the energy saving compared with those conventionally cooperative sensing schemes.
基金the National Key Research and Development Program of China(Grant No.2017YFB0405203)the National Natural Science Foundation of China(Grant No.61627821).
文摘A novel Er:YAG laser system operating at 1645 nm with high pulse-repetition-frequency(PRF)of kHz level is demonstrated.A ring cavity with double gain medium end-pumped by two fiber lasers is utilized to obtain high pulse energy.A novel‘triple-reflection’configuration on a piezoelectric actuator(PZT)is adopted to achieve high-repetition-rate at 3-kHz operation with the ramp-fire locking method.Single frequency pulses with maximum average power of 18.3 W at 3 kHz are obtained,and the pulse duration time is 318 ns.The full line width at half maximum(FWHM)of the pulses measured by the heterodyne technique is 1.71 MHz at 3 kHz.To the best of our knowledge,this is the highest PRF single-frequency laser pulses achieved based Er:YAG gain medium.
基金Part of the work was supported by the National Natural Science Foundation of China(No.61702034)Part of the work was supported by the Opening Project of Guangdong Province Key Laboratory of Information Security Technology(Grant No.2017B030314131).
文摘Steganalysis is a technique used for detecting the existence of secret information embedded into cover media such as images and videos.Currently,with the higher speed of the Internet,videos have become a kind of main methods for transferring information.The latest video coding standard High Efficiency Video Coding(HEVC)shows better coding performance compared with the H.264/AVC standard published in the previous time.Therefore,since the HEVC was published,HEVC videos have been widely used as carriers of hidden information.In this paper,a steganalysis algorithm is proposed to detect the latest HEVC video steganography method which is based on the modification of Prediction Units(PU)partition modes.To detect the embedded data,All the PU partition modes are extracted from P pictures,and the probability of each PU partition mode in cover videos and stego videos is adopted as the classification feature.Furthermore,feature optimization is applied,that the 25-dimensional steganalysis feature has been reduced to the 3-dimensional feature.Then the Support Vector Machine(SVM)is used to identify stego videos.It is demonstrated in experimental results that the proposed steganalysis algorithm can effectively detect the stego videos,and much higher classification accuracy has been achieved compared with state-of-the-art work.
基金This work is supported by the National Natural Science Foundation of China(No.U1736118)the Natural Science Foundation of Guangdong(No.2016A030313350)+3 种基金the Special Funds for Science and Technology Development of Guangdong(No.2016KZ010103)the Key Project of Scientific Research Plan of Guangzhou(No.201804020068)the Fundamental Research Funds for the Central Universities(No.16lgjc83 and No.17lgjc45)the Science and Technology Planning Project of Guangdong Province(Grant No.2017A040405051).
文摘In recent years,binary image steganography has developed so rapidly that the research of binary image steganalysis becomes more important for information security.In most state-of-the-art binary image steganographic schemes,they always find out the flippable pixels to minimize the embedding distortions.For this reason,the stego images generated by the previous schemes maintain visual quality and it is hard for steganalyzer to capture the embedding trace in spacial domain.However,the distortion maps can be calculated for cover and stego images and the difference between them is significant.In this paper,a novel binary image steganalytic scheme is proposed,which is based on distortion level co-occurrence matrix.The proposed scheme first generates the corresponding distortion maps for cover and stego images.Then the co-occurrence matrix is constructed on the distortion level maps to represent the features of cover and stego images.Finally,support vector machine,based on the gaussian kernel,is used to classify the features.Compared with the prior steganalytic methods,experimental results demonstrate that the proposed scheme can effectively detect stego images.
基金国家自然科学基金，广东省自然科学基金，Funding of National Education Ministry of P.R.China
文摘Robustness is one of the most important requirements of digital watermarking for many applications. Spread-spectrum based methods are not effective enough to ensure their robustness. By modeling digital watermarking as digital communications, several researchers proposed using error correcting coding (ECC) to improve robustness. However, an important fact that has long been neglected is that due to the imperceptibility requirement, the redundancy introduced by ECC will lead to a decrease of the magnitude of watermark signal. Therefore, a problem arises naturally:Could the usage of ECC effectively improve the robustness of watermarking? This paper addresses this problem from the perspectives of both theoretical analysis and experimental investigation. Our investigation shows that ECG cannot effectively improve the robustness of watermarking against a great majority of various attacks except for cropping and jitter attacks. Hence, ECC should not be considered as a universal measure that can be employed to enhance robustness of watermarking.
基金Supported by the National Natural Science Foundation of China(No.61076021)the National Basic Research Program of China(No.2009CB320903)China Postdoctoral Science Foundation(No.2012M511364)
文摘An adaptive pipelining scheme for H.264/AVC context-based adaptive binary arithmetic coding(CABAC) decoder for high definition(HD) applications is proposed to solve data hazard problems coming from the data dependencies in CABAC decoding process.An efficiency model of CABAC decoding pipeline is derived according to the analysis of a common pipeline.Based on that,several adaptive strategies are provided.The pipelining scheme with these strategies can be adaptive to different types of syntax elements(SEs) and the pipeline will not stall during decoding process when these strategies are adopted.In addition,the decoder proposed can fully support H.264/AVC high4:2:2 profile and the experimental results show that the efficiency of decoder is much higher than other architectures with one engine.Taking both performance and cost into consideration,our design makes a good tradeoff compared with other work and it is sufficient for HD real-time decoding.
基金the National Key Research and Development Program of China(No.2017YFE0112600)the National Science Foundation of China[No.61971454,No.91438101&No.61771499]the National Science Foundation of Guangdong,China[No.2016A030308008].
文摘As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,e.g.,weather conditions,evaporation ducting,and ship rocking caused by waves.To ensure the data transmission reliability,the block Markov superposition transmission(BMST)codes,which are easily configurable and have predictable performance,are applied in this study.Meanwhile,the physical-layer network coding(PNC)scheme with spatial modulation(SM)is adopted to improve the spectrum utilization.For the BMST-SMPNC system,we propose an iterative algorithm,which utilizes the channel observations and the a priori information from BMST decoder,to compute the soft information corresponding to the XORed bits constructed by the relay node.The results indicate that the proposed scheme outperforms the convolutional coded SM-PNC over fast-fading Rician channels.Especially,the performance can be easily improved in high spatial correlation maritime channel by increasing the memory m.
基金Supported by the National Natural Science Foundation of China (No. 60403007, No. 60503006, No. 60572059)the Natural Science Foundation of Guangdong Province, China (No.05300706).
文摘Proxy signatures have been used to enable the transfer of digital signing power within some context and ring signatures can be used to provide the anonymity of a signer. By combining the functionalities of proxy signatures and ring signatures, this paper introduces a new concept, named ring proxy signature, which is a proxy signature generated by an anonymous member from a set of potential signers. The paper also constructs the first concrete ring proxy signature scheme based on the provably secure Schnorr's signatures and two ID-based ring proxy signature schemes. The security analysis is provided as well.
基金supported by the National Natural Science Foundation of China(Nos.U2001202,62072480,U1736118)the National Key R&D Program of China(Nos.2019QY2202,2019QY(Y)0207)+1 种基金the Key Areas R&D Program of Guangdong(No.2019B010136002)the Key Scientific Research Program of Guangzhou(No.201804020068).
文摘In recent years,with the rapid development of deep learning technologies,some neural network models have been applied to generate fake media.DeepFakes,a deep learning based forgery technology,can tamper with the face easily and generate fake videos that are difficult to be distinguished by human eyes.The spread of face manipulation videos is very easy to bring fake information.Therefore,it is important to develop effective detection methods to verify the authenticity of the videos.Due to that it is still challenging for current forgery technologies to generate all facial details and the blending operations are used in the forgery process,the texture details of the fake face are insufficient.Therefore,in this paper,a new method is proposed to detect DeepFake videos.Firstly,the texture features are constructed,which are based on the gradient domain,standard deviation,gray level co-occurrence matrix and wavelet transform of the face region.Then,the features are processed by the feature selection method to form a discriminant feature vector,which is finally employed to SVM for classification at the frame level.The experimental results on the mainstream DeepFake datasets demonstrate that the proposed method can achieve ideal performance,proving the effectiveness of the proposed method for DeepFake videos detection.
基金the National Natural Science Foundation of China(No.62072480)the Key Areas R&D Program of Guangdong(No.2019B010136002)the Key ScientificResearch Program of Guangzhou(No.201804020068).
文摘The estimation of image resampling factors is an important problem in image forensics.Among all the resampling factor estimation methods,spectrumbased methods are one of the most widely used methods and have attracted a lot of research interest.However,because of inherent ambiguity,spectrum-based methods fail to discriminate upscale and downscale operations without any prior information.In general,the application of resampling leaves detectable traces in both spatial domain and frequency domain of a resampled image.Firstly,the resampling process will introduce correlations between neighboring pixels.In this case,a set of periodic pixels that are correlated to their neighbors can be found in a resampled image.Secondly,the resampled image has distinct and strong peaks on spectrum while the spectrum of original image has no clear peaks.Hence,in this paper,we propose a dual-stream convolutional neural network for image resampling factors estimation.One of the two streams is gray stream whose purpose is to extract resampling traces features directly from the rescaled images.The other is frequency stream that discovers the differences of spectrum between rescaled and original images.The features from two streams are then fused to construct a feature representation including the resampling traces left in spatial and frequency domain,which is later fed into softmax layer for resampling factor estimation.Experimental results show that the proposed method is effective on resampling factor estimation and outperforms some CNN-based methods.
