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Cognitive Erasure-Coded Data Update and Repair for Mitigating I/O Overhead 认领 引用
1
作者 Bing Wei Ming Zhong +2 位作者 Qian Chen Yi Wu Yubin Li 《Computers, Materials & Continua》 SCIE EI 2026年第2期1706-1725,共20页
In erasure-coded storage systems,updating data requires parity maintenance,which often leads to significant I/O amplification due to“write-after-read”operations.Furthermore,scattered parity placement increases disk ... In erasure-coded storage systems,updating data requires parity maintenance,which often leads to significant I/O amplification due to“write-after-read”operations.Furthermore,scattered parity placement increases disk seek overhead during repair,resulting in degraded system performance.To address these challenges,this paper proposes a Cognitive Update and Repair Method(CURM)that leverages machine learning to classify files into writeonly,read-only,and read-write categories,enabling tailored update and repair strategies.For write-only and read-write files,CURM employs a data-differencemechanism combined with fine-grained I/O scheduling to minimize redundant read operations and mitigate I/O amplification.For read-write files,CURM further reserves adjacent disk space near parity blocks,supporting parallel reads and reducing disk seek overhead during repair.We implement CURM in a prototype system,Cognitive Update and Repair File System(CURFS),and conduct extensive experiments using realworld Network File System(NFS)and Microsoft Research(MSR)workloads on a 25-node cluster.Experimental results demonstrate that CURMimproves data update throughput by up to 82.52%,reduces recovery time by up to 47.47%,and decreases long-term storage overhead by more than 15% compared to state-of-the-art methods including Full Logging(FL),ParityLogging(PL),ParityLoggingwithReservedspace(PLR),andPARIX.These results validate the effectiveness of CURM in enhancing both update and repair performance,providing a scalable and efficient solution for large-scale erasure-coded storage systems. 展开更多
关键词 Erasure coding machine learning cognitive update and repair I/O amplification mitigation seekefficient recovery
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Programmable phase-coded microwave signal generation with tunable duty cycle via bias voltage modulation in an optoelectronic oscillator 认领 引用
2
作者 Hang Xiao Di Peng +6 位作者 Ya Han Heyun Tan Jianping Li Meng Xiang Songnian Fu Shuoyang Qiu Yuwen Qin 《Advanced Photonics Nexus》 CSCD 2026年第3期167-175,共9页
Key parameters of microwave signals,including frequency,phase noise,period,and pulse width,exert a profound influence on the detection performance of radar systems.Optoelectronic oscillators(OEOs)offer the distinct ad... Key parameters of microwave signals,including frequency,phase noise,period,and pulse width,exert a profound influence on the detection performance of radar systems.Optoelectronic oscillators(OEOs)offer the distinct advantage of enabling direct generation of microwave signals with frequency-independent ultra-low phase noise.By integrating external modulation mechanisms,OEOs can further produce signals with more complex waveforms,thereby effectively addressing the demanding requirements of modern radar systems.We propose and demonstrate a method for generating programmable phase-coded microwave signals with tunable duty cycles in an OEO.The approach utilizes simple bias voltage modulation,where a voltage-level-coded signal is injected into the direct-current bias port of the push-pull Mach–Zehnder modulator(MZM)within the OEO loop.Binary phase coding is achieved by exploiting the reverse-phase characteristic of the minimum transmission point of the MZM.The duty cycle of the generated phase-coded microwave signal is adjusted by varying that of the injected signal.Simulations and experiments confirm the generation of microwave signals with excellent phase-coding performance and high spectral coherence. 展开更多
关键词 optoelectronic oscillator phase code tunable duty cycle radar ranging
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Design of Serially Concatenated Two-Level Polar Coded Modulation System with Low-Complexity 认领 引用
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作者 Zhou Lin Liao Guojun +3 位作者 Xu Lei An Ran Xie Xianzhong Wang Xi 《China Communications》 SCIE EI CSCD 2025年第1期102-110,共9页
Multilevel coding(MLC)is a commonly used polar coded modulation scheme,but challenging to implement in engineering due to its high complexity and long decoding delay for high-order modulations.To address these limitat... Multilevel coding(MLC)is a commonly used polar coded modulation scheme,but challenging to implement in engineering due to its high complexity and long decoding delay for high-order modulations.To address these limitations,a novel two-level serially concatenated MLC scheme,in which the bitlevels with similar reliability are bundled and transmitted together,is proposed.The proposed scheme hierarchically protects the two bit-level sets:the bitlevel sets at the higher level are sufficiently reliable and do not require excessive resources for protection,whereas only the bit-level sets at the lower level are encoded by polar codes.The proposed scheme has the advantages of low power consumption,low delay and high reliability.Moreover,an optimized constellation signal labeling rule that can enhance the performance is proposed.Finally,the superiority of the proposed scheme is validated through the theoretical analysis and simulation results.Compared with the bit interleaving coding modulation(BICM)scheme,under 256-quadrature amplitude modulation(QAM),the proposed scheme attains a performance gain of 1.0 dB while reducing the decoding complexity by 54.55%. 展开更多
关键词 bit-interleaved coded modulation high-order modulation multilevel coding polar codes
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Coded Distributed Computing for System with Stragglers 认领 引用
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作者 Xu Jiasheng Kang Huquan +5 位作者 Zhang Haonan Fu Luoyi Long Fei Cao Xinde Wang Xinbing Zhou Chenghu 《China Communications》 SCIE EI CSCD 2025年第8期298-313,共16页
Distributed computing is an important topic in the field of wireless communications and networking,and its high efficiency in handling large amounts of data is particularly noteworthy.Although distributed computing be... Distributed computing is an important topic in the field of wireless communications and networking,and its high efficiency in handling large amounts of data is particularly noteworthy.Although distributed computing benefits from its ability of processing data in parallel,the communication burden between different servers is incurred,thereby the computation process is detained.Recent researches have applied coding in distributed computing to reduce the communication burden,where repetitive computation is utilized to enable multicast opportunities so that the same coded information can be reused across different servers.To handle the computation tasks in practical heterogeneous systems,we propose a novel coding scheme to effectively mitigate the "straggling effect" in distributed computing.We assume that there are two types of servers in the system and the only difference between them is their computational capabilities,the servers with lower computational capabilities are called stragglers.Given any ratio of fast servers to slow servers and any gap of computational capabilities between them,we achieve approximately the same computation time for both fast and slow servers by assigning different amounts of computation tasks to them,thus reducing the overall computation time.Furthermore,we investigate the informationtheoretic lower bound of the inter-communication load and show that the lower bound is within a constant multiplicative gap to the upper bound achieved by our scheme.Various simulations also validate the effectiveness of the proposed scheme. 展开更多
关键词 coded computation communication load distributed computing straggling effect
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Hybrid DF and SIR Forwarding Strategy in Conventional and Distributed Alamouti Space-Time Coded Cooperative Networks 认领 引用 被引量：1
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作者 Slim Chaoui Omar Alruwaili +1 位作者 Faeiz Alserhani Haifa Harrouch 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第2期1933-1954,共22页
In this paper,we propose a hybrid decode-and-forward and soft information relaying(HDFSIR)strategy to mitigate error propagation in coded cooperative communications.In the HDFSIR approach,the relay operates in decode-... In this paper,we propose a hybrid decode-and-forward and soft information relaying(HDFSIR)strategy to mitigate error propagation in coded cooperative communications.In the HDFSIR approach,the relay operates in decode-and-forward(DF)mode when it successfully decodes the received message;otherwise,it switches to soft information relaying(SIR)mode.The benefits of the DF and SIR forwarding strategies are combined to achieve better performance than deploying the DF or SIR strategy alone.Closed-form expressions for the outage probability and symbol error rate(SER)are derived for coded cooperative communication with HDFSIR and energy-harvesting relays.Additionally,we introduce a novel normalized log-likelihood-ratio based soft estimation symbol(NL-SES)mapping technique,which enhances soft symbol accuracy for higher-order modulation,and propose a model characterizing the relationship between the estimated complex soft symbol and the actual high-order modulated symbol.Further-more,the hybrid DF-SIR strategy is extended to a distributed Alamouti space-time-coded cooperative network.To evaluate the~performance of the proposed HDFSIR strategy,we implement extensive Monte Carlo simulations under varying channel conditions.Results demonstrate significant improvements with the hybrid technique outperforming individual DF and SIR strategies in both conventional and distributed Alamouti space-time coded cooperative networks.Moreover,at a SER of 10-3,the proposed NL-SES mapping demonstrated a 3.5 dB performance gain over the conventional averaging one,highlighting its superior accuracy in estimating soft symbols for quadrature phase-shift keying modulation. 展开更多
关键词 Cooperative communication soft information relaying soft symbols modeling cooperative diversity gain distributed Alamouti space-time code
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True random coded photon counting Lidar 认领 引用 被引量：9
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作者 Bo Liu Yang Yu +1 位作者 Zhen Chen Weiqiang Han 《Opto-Electronic Advances》 SCIE EI CAS 2020年第2期12-17,共6页
A true random coded photon counting Lidar system is proposed in this paper,in which a single photon detector acts as the true random sequence signal generator instead of the traditional function generator.Compared wit... A true random coded photon counting Lidar system is proposed in this paper,in which a single photon detector acts as the true random sequence signal generator instead of the traditional function generator.Compared with the traditional pseudo-random coded method,the true random coded method not only improves the anti-crosstalk capability of the system,but more importantly,it effectively overcomes the adverse effect of the detector’s dead time on the ranging performance.The experiment results show that the ranging performance of the true random coded method is obviously better than that of the pseudo-random coded method.As a result,a three-dimensional scanning imaging of a model car is completed by the true random coded method. 展开更多
关键词 Lidar photon counting true random coded pseudo-random coded
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Optimization of Mapping Rule of Bit-Interleaved Turbo Coded Modulation with 16QAM 认领 引用 被引量：1
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作者 FEI Ze-song YANG Yu +1 位作者 LIU Lin-nan KUANG Jing-ming 《Journal of Beijing Institute of Technology》 EI CAS 2005年第1期18-21,共4页
Optimization of mapping rule of bit-interleaved Turbo coded modulation with 16 quadrature amplitude modulation(QAM)is investigated based on different impacts of various encoded bits sequence on Turbo decoding performa... Optimization of mapping rule of bit-interleaved Turbo coded modulation with 16 quadrature amplitude modulation(QAM)is investigated based on different impacts of various encoded bits sequence on Turbo decoding performance.Furthermore,bit-interleaved in-phase and quadrature phase(I-Q)Turbo coded modulation scheme are designed similarly with I-Q trellis coded modulation(TCM).Through performance evaluation and analysis,it can be seen that the novel mapping rule outperforms traditional one and the I-Q Turbo coded modulation can not achieve good performance as expected.Therefore,there is not obvious advantage in using I-Q method in bit-interleaved Turbo coded modulation. 展开更多
关键词 binary Turbo coded modulation quadrature amplitude modulation(QAM) mapping rule in-phase and quadrature(I-Q)coded modulation
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Elimination of the Background Noise of the Decoded Image in Fresnel Zone Plate Scanning Holography 认领 引用
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作者 孙萍 谢敬辉 《Journal of Beijing Institute of Technology》 EI CAS 2005年第3期225-228,共4页
A method of digitally high pass filtering in frequency domain is proposed to eliminate the background noise of the decoded image in Fresnel zone plate scanning holography. The high pass filter is designed as a circula... A method of digitally high pass filtering in frequency domain is proposed to eliminate the background noise of the decoded image in Fresnel zone plate scanning holography. The high pass filter is designed as a circular stop, which should be suitable to suppressing the background noise significantly and remain much low frequency information of the object. The principle of high pass filtering is that the Fourier transform of the decoded image is multiplied with the high pass filter. Thus the frequency spectrum of the decoded image without the background noise is achieved. By inverse Fourier transform of the spectrum of the decoded image after multiplying operation, the decoded image without the background noise is obtained. Both of the computer simulations and the experimental results show that the contrast and the signal-to-noise ratio of the decoded image are significantly improved with digital filtering. 展开更多
关键词 Fresnel zone plate scanning holography digitally high pass filtering coded image decoded image
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Correction:Deep Learning-Enhanced Brain Tumor Prediction via Entropy-Coded BPSO in CIELAB Color Space 认领 引用
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作者 Mudassir Khalil Muhammad Imran Sharif +3 位作者 Ahmed Naeem Muhammad Umar Chaudhry Hafiz Tayyab Rauf Adham E.Ragab 《Computers, Materials & Continua》 SCIE EI 2025年第1期1461-1461,共1页
In the article“Deep Learning-Enhanced Brain Tumor Prediction via Entropy-Coded BPSO in CIELAB Color Space”by Mudassir Khalil,Muhammad Imran Sharif,Ahmed Naeem,Muhammad Umar Chaudhry,Hafiz Tayyab Rauf,Adham E.Ragab C... In the article“Deep Learning-Enhanced Brain Tumor Prediction via Entropy-Coded BPSO in CIELAB Color Space”by Mudassir Khalil,Muhammad Imran Sharif,Ahmed Naeem,Muhammad Umar Chaudhry,Hafiz Tayyab Rauf,Adham E.Ragab Computers,Materials&Continua,2023,Vol.77,No.2,pp.2031–2047.DOI:10.32604/cmc.2023.043687,URL:http://gffzz9e48629005df441askfcbcfpb6fv9696k.ffgz.tsg.suse.edu.cn/cmc/v77n2/54831,there was an error regarding the affiliation for the author Hafiz Tayyab Rauf.Instead of“Centre for Smart Systems,AI and Cybersecurity,Staffordshire University,Stoke-on-Trent,ST42DE,UK”,the affiliation should be“Independent Researcher,Bradford,BD80HS,UK”. 展开更多
关键词 Deep Code CIELAB
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Performance improvement of magneto-acousto-electrical tomography for biological tissues with sinusoid-Barker coded excitation 认领 引用 被引量：10
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作者 Zheng-Feng Yu Yan Zhou +4 位作者 Yu-Zhi Li Qing-Yu Ma Ge-Pu Guol Juan Tu Dong Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第9期346-353,共8页
By combining magnetics, acoustics and electrics, the magneto-acoustic-electrical tomography（MAET） proves to possess the capability of differentiating electrical impedance variation and thus improving the spatial res... By combining magnetics, acoustics and electrics, the magneto-acoustic-electrical tomography（MAET） proves to possess the capability of differentiating electrical impedance variation and thus improving the spatial resolution. However,the signal-to-noise ratio（SNR） of the collected MAET signal is still unsatisfactory for biological tissues with low-level electrical conductivity. In this study, the formula of MAET measurement with sinusoid-Barker coded excitation is derived and simplified for a planar piston transducer. Numerical simulations are conducted for a four-layered gel phantom with the 13-bit sinusoid-Barker coded excitation, and the performances of wave packet recovery with side-lobe suppression are improved by using the mismatched compression filter, which is also demonstrated by experimentally measuring a three-layered gel phantom. It is demonstrated that comparing with the single-cycle sinusoidal excitation, the amplitude of the driving signal can be reduced greatly with an SNR enhancement of 10 dB using the 13-bit sinusoid-Barker coded excitation. The amplitude and polarity of the wave packet filtered from the collected MAET signal can be used to achieve the conductivity derivative at the tissue boundary. In this study, we apply the sinusoid-Barker coded modulation method and the mismatched suppression scheme to MAET measurement to ensure the safety for biological tissues with improved SNR and spatial resolution, and suggest the potential applications in biomedical imaging. 展开更多
关键词 magneto-acousto-electrical tomography sinusoid-Barker coded excitation mismatched compression filter side lobe suppression
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Science Letters:A new coding scheme in coded ultrasound using staggering repetition interval 认领 引用 被引量：3
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作者 Cheng JIN Si-ping CHEN Zheng-di QIN 《Journal of Zhejiang University-SCIENCE A》 SCIE EI CAS 2009年第8期1213-1216,共4页
The increase of frame rate,though with the potential in a coded ultrasound system,is generally concomitant with the simultaneous transmission of a number of apertures,and in consequence leads to increased cross-talks ... The increase of frame rate,though with the potential in a coded ultrasound system,is generally concomitant with the simultaneous transmission of a number of apertures,and in consequence leads to increased cross-talks between different apertures.In view of this,a new coding scheme using staggering repetition interval was proposed.The transmitting signals were constructed by repeating the two(or more) modulated codes using staggering repetition interval,and then allocated to and transmitted simultaneously among different apertures.The decoding process was based on the subsection-matched filter under the assistance of different matched filters for different apertures.At last the outputs of subsection-matched filtering were added together.Staggering changed the positions of cross-correlation(CC) peaks from coinciding,which resulted in an effective reduction of CC.Our theoretical analysis and simulations showed that,the coding scheme can be used to reduce cross-talk,and a good cross-talk reduction will be achieved if the staggering delay is kept in an appropriate range. 展开更多
关键词 Coded ultrasound Frame rate Cross-correlation （CC） Staggering Ultrasonic imaging
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Piecewise spectrally band-pass for compressive coded aperture spectral imaging 认领 引用 被引量：2
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作者 钱路路 吕群波 +1 位作者 黄旻 相里斌 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期248-253,共6页
Coded aperture snapshot spectral imaging(CASSI) has been discussed in recent years. It has the remarkable advantages of high optical throughput, snapshot imaging, etc. The entire spatial-spectral data-cube can be reco... Coded aperture snapshot spectral imaging(CASSI) has been discussed in recent years. It has the remarkable advantages of high optical throughput, snapshot imaging, etc. The entire spatial-spectral data-cube can be reconstructed with just a single two-dimensional(2D) compressive sensing measurement. On the other hand, for less spectrally sparse scenes,the insufficiency of sparse sampling and aliasing in spatial-spectral images reduce the accuracy of reconstructed threedimensional(3D) spectral cube. To solve this problem, this paper extends the improved CASSI. A band-pass filter array is mounted on the coded mask, and then the first image plane is divided into some continuous spectral sub-band areas. The entire 3D spectral cube could be captured by the relative movement between the object and the instrument. The principle analysis and imaging simulation are presented. Compared with peak signal-to-noise ratio(PSNR) and the information entropy of the reconstructed images at different numbers of spectral sub-band areas, the reconstructed 3D spectral cube reveals an observable improvement in the reconstruction fidelity, with an increase in the number of the sub-bands and a simultaneous decrease in the number of spectral channels of each sub-band. 展开更多
关键词 coded aperture spectral imaging compressive sensing information reconstruction
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Feedback Stabilization over Wireless Network Using Adaptive Coded Modulation 认领 引用 被引量：6
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作者 Li Yang Xin-Ping Guan +1 位作者 Cheng-Nian Long Xiao-Yuan Luo 《International Journal of Automation and computing》 2008年第4期381-388,共8页
In this paper,we apply adaptive coded modulation (ACM) schemes to a wireless networked control system (WNCS) to improve the energy efficiency and increase the data rate over a fading channel.To capture the characteris... In this paper,we apply adaptive coded modulation (ACM) schemes to a wireless networked control system (WNCS) to improve the energy efficiency and increase the data rate over a fading channel.To capture the characteristics of varying rate, interference,and routing in wireless transmission channels,the concepts of equivalent delay (ED) and networked condition index (NCI) are introduced.Also,the analytic lower and upper bounds of EDs are obtained.Furthermore,we model the WNCS as a multicontroller switched system (MSS) under consideration of EDs and loss index in the wireless transmission.Sufficient stability condition of the closed-loop WNCS and corresponding dynamic state feedback controllers are derived in terms of linear matrix inequality (LMI). Numerical results show the validity and advantage of our proposed control strategies. 展开更多
关键词 Wireless networked control system (WNCS) adaptive coded modulation (ACM) equivalent delay (ED) networked condition index (NCI) multicontroller switched system (MSS) stability.
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An improved deconvolution method for X-ray coded imaging in inertial confinement fusion 认领 引用 被引量：1
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作者 赵宗清 何卫华 +4 位作者 王剑 郝轶丹 曹磊峰 谷渝秋 张保汉 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第10期281-286,共6页
In inertial confinement fusion （ICF）, X-ray coded imaging is considered as the most potential means to diagnose the compressed core. The traditional Richardson-Lucy （RL） method has a strong ability to deblur the i... In inertial confinement fusion （ICF）, X-ray coded imaging is considered as the most potential means to diagnose the compressed core. The traditional Richardson-Lucy （RL） method has a strong ability to deblur the image where the noise follows the Poisson distribution. However, it always suffers from over-fitting and noise amplification, especially when the signal-to-noise ratio of image is relatively low. In this paper, we propose an improved deconvolution method for X-ray coded imaging. We model the image data as a set of independent Gaussian distributions and derive the iterative solution with a maximum-likelihood scheme. The experimental results on X-ray coded imaging data demonstrate that this method is superior to the RL method in terms of anti-overfitting and noise suppression. 展开更多
关键词 inertial confinement fusion coded imaging deconvolution Gaussian distribution maximum-likelihood
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Novel non-coherent integration method using binary phase-coded radar signal 认领 引用 被引量：3
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作者 田黎育 何苗 +1 位作者 刘斌 傅雄军 《Journal of Beijing Institute of Technology》 EI CAS 2013年第1期60-66,共7页
The m series with 511 bits is taken as an example being applied in non-coherent integra- tion algorithm. A method to choose the bi-phase code is presented, which is 15 kinds of codes are picked out of 511 kinds of m s... The m series with 511 bits is taken as an example being applied in non-coherent integra- tion algorithm. A method to choose the bi-phase code is presented, which is 15 kinds of codes are picked out of 511 kinds of m series to do non-coherent integration. It is indicated that the power in- creasing times of larger target sidelobe is less than the power increasing times of smaller target main- lobe because of the larger target＇ s pseudo-randomness. Smaller target is integrated from larger tar- get sidelobe, which strengthens the detection capability of radar for smaller targets. According to the sidelobes distributing characteristic, a method is presented in this paper to remove the estimated sidelobes mean value for signal detection after non-coherent integration. Simulation results present that the SNR of small target can be improved approximately 6. 5 dB by the proposed method. 展开更多
关键词 binary phase-coded signal non-coherent integration code agility peak sidelobe level（PSL） mainlobe-peak sidelobe ratio
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An Unambiguity and Anti-Range Eclipse Method for PD Radar Using Biphase Coded Signals 认领 引用 被引量：1
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作者 Jihong Yan Weihan Ni +1 位作者 Jianshu Zhai Haiyang Dong 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第2期1337-1351,共15页
Target detection is an important research content in the radar field.At present,efforts are being made to optimize the precision of detection information.In this paper,we use the high pulse repetition frequency(HPRF)t... Target detection is an important research content in the radar field.At present,efforts are being made to optimize the precision of detection information.In this paper,we use the high pulse repetition frequency(HPRF)transmission method and orthogonal biphase coded signals in each pulse to avoid velocity ambiguity and range ambiguity of radar detection.In addition,We also apply Walsh matrix and genetic algorithm(GA)to generate satisfying orthogonal biphase coded signals with low auto-correlation sidelobe peak and cross-correlation peak,which make the results more accurate.In a radar receiver,data rearrangement of echo signals is performed,and then pulse compression and moving target detection(MTD)are utilized to get the final velocity and range information of a target without velocity ambiguity and range ambiguity.Besides,a small transmitting pulse time width is adopted to reduce the working blind area,and two different high pulse repetition frequencies(HPRFs)are adopted to solve the problem of range eclipse.Simulation results finally prove the effectiveness and feasibility of the proposed method. 展开更多
关键词 Biphase coded velocity ambiguity range ambiguity genetic algorithm range eclipse
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Optimization of ultrasonic elastography by coded excitation and transmit-side multi-frequency compounding 认领 引用 被引量：1
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作者 张志宏 刘昊霖 +1 位作者 何颖妮 刘东权 《Journal of Central South University》 SCIE EI CAS 2014年第3期1003-1010,共8页
To improve the quality of ultrasonic elastography, by taking the advantage of code excitation and frequency compounding, a transmitting-side multi-frequency with coded excitation for elastography （TFCCE） was propose... To improve the quality of ultrasonic elastography, by taking the advantage of code excitation and frequency compounding, a transmitting-side multi-frequency with coded excitation for elastography （TFCCE） was proposed. TFCCE adopts the chirp signal excitation scheme and strikes a balance in the selection of sub-signal bandwidth, the bandwidth overlap and the number of sub-strain image based on theoretical derivation, so as to further improve the quality of elastic image. Experiments have proved that, compared with the other optimizing methods, the elastographyic signal-to-noise ratio（Re-SN） and contrast-to-noise ratio（Re-CN） are improved significantly with different echo signal-to-noise ratios （ReSN） and attenuation coefficients. When ReSN is 50 dB, compared with short pulse, Rc-SN and Re-CN obtained by TFCCE increase by 53% and 143%, respectively. Moreover, in a deeper investigation （85-95 mm）, the image has lower strain noise and clear details. When the attenuation coefficient is in the range of 0-1 dB/（cm.MHz）, Re-SN and Re-CN obtained by TFCCE can be kept in moderate ranges of 5〈Re-SN〈6.8 and 11.4〈Re-CN〈15.2, respectively. In particular, for higher tissue attenuation, the basic image quality cannot be ensured with short pulse excitation, while mediocre quality strain figure can be obtained by TFCCE. Therefore, the TFCCE technology can effectively improve the elastography quality and can be applied to ultrasonic clinical trials. 展开更多
关键词 ultrasonic elastography coded excitation transmit-side multi-frequency compounding elastographyic signal-to-noise ratio echo signal-to-noise ratio contrast-to-noise ratio
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Finite rate of innovation sparse sampling for a binary frequency-coded ultrasonic signal 认领 引用 被引量：1
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作者 Song Shoupeng Chen Yiqian +1 位作者 Xu Baowen Qiu Yue 《Journal of Southeast University(English Edition)》 EI CAS 2022年第1期27-35,共9页
To achieve sparse sampling on a coded ultrasonic signal,the finite rate of innovation(FRI)sparse sampling technique is proposed on a binary frequency-coded(BFC)ultrasonic signal.A framework of FRI-based sparse samplin... To achieve sparse sampling on a coded ultrasonic signal,the finite rate of innovation(FRI)sparse sampling technique is proposed on a binary frequency-coded(BFC)ultrasonic signal.A framework of FRI-based sparse sampling for an ultrasonic signal pulse is presented.Differences between the pulse and the coded ultrasonic signal are analyzed,and a response mathematical model of the coded ultrasonic signal is established.A time-domain transform algorithm,called the high-order moment method,is applied to obtain a pulse stream signal to assist BFC ultrasonic signal sparse sampling.A sampling of the output signal with a uniform interval is then performed after modulating the pulse stream signal by a sampling kernel.FRI-based sparse sampling is performed using a self-made circuit on an aluminum alloy sample.Experimental results show that the sampling rate reduces to 0.5 MHz,which is at least 12.8 MHz in the Nyquist sampling mode.The echo peak amplitude and the time of flight are estimated from the sparse sampling data with maximum errors of 9.324%and 0.031%,respectively.This research can provide a theoretical basis and practical application reference for reducing the sampling rate and data volume in coded ultrasonic testing. 展开更多
关键词 coded ultrasonic signal finite rate of innovation high-order moment sparse sampling circuit implementation
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Robustness and precision evaluation of the form error of micro-structured surfaces using real coded genetic algorithm 认领 引用 被引量：2
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作者 周京博 孙涛 《Journal of Beijing Institute of Technology》 EI CAS 2012年第4期479-486,共8页
To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm （RCGA）. The meth- od employed the average squar... To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm （RCGA）. The meth- od employed the average squared distance as the matching criterion. The point to surface distance was achieved by use of iterative method and the modeling of RCGA for the surface matching was also presented in detail. Parameter selection for RCGA including the crossover rate and population size was discussed. Evaluation results of series simulated surfaces without form error show that this method can achieve the accuracy of root mean square deviation （ Sq ） less than 1 nm and surface pro- file error （ St ） less than 4 nm. Evaluation of the surfaces with different simulated errors illustrates that the proposed method can also robustly obtain the form error with nano-meter precision. The e- valuation of actual measured surfaces further indicates that the proposed method is capable of pre- cisely evaluating micro-structured surfaces. 展开更多
关键词 micro-structured surfaces form error evaluation surface matching real coded geneticalgorithm
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Implementation of a kind of FPGA-based binary phase coded radar signal processor architecture 认领 引用 被引量：1
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作者 田黎育 孙密 万阳良 《Journal of Beijing Institute of Technology》 EI CAS 2012年第4期526-531,共6页
A flexible field programmable gate array based radar signal processor is presented. The radar signal processor mainly consists of five functional modules： radar system timer, binary phase coded pulse compression（PC... A flexible field programmable gate array based radar signal processor is presented. The radar signal processor mainly consists of five functional modules： radar system timer, binary phase coded pulse compression（PC）, moving target detection （MTD）, constant false alarm rate （CFAR） and target dots processing. Preliminary target dots information is obtained in PC, MTD, and CFAR modules and Nios I! CPU is used for target dots combination and false sidelobe target removing. Sys- tem on programmable chip （SOPC） technique is adopted in the system in which SDRAM is used to cache data. Finally, a FPGA-based binary phase coded radar signal processor is realized and simula- tion result is given. 展开更多
关键词 field programmable gate array（FPGA） radar signal processor system on programma-ble chip （SOPC） binary phase coded
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