Herein,a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity.Fractional-order...Herein,a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity.Fractional-order calculus has the inherent advantage of easily jumping out of local extreme values;here,it is introduced into the particle-swarm algorithm to invert the true temperature.An improved adaptive-adjustment mechanism is applied to automatically adjust the current velocity order of the particles and update their velocity and position values,increasing the accuracy of the true temperature values.The results of simulations using the proposed algorithm were compared with three algorithms using typical emissivity models:the internal penalty function algorithm,the optimization function(fmincon)algorithm,and the conventional particle-swarm optimization algorithm.The results show that the proposed algorithm has good accuracy for true-temperature inversion.Actual experimental results from a rocket-motor plume were used to demonstrate that the true-temperature inversion results of this algorithm are in good agreement with the theoretical true-temperature values.展开更多
Solving large scale system of Simultaneous Linear Equations (SLE) has been (and continue to be) a major challenging problem for many real-world engineering and science applications. Solving SLE with singular coefficie...Solving large scale system of Simultaneous Linear Equations (SLE) has been (and continue to be) a major challenging problem for many real-world engineering and science applications. Solving SLE with singular coefficient matrices arises from various engineering and sciences applications [1]-[6]. In this paper, efficient numerical procedures for finding the generalized (or pseudo) inverse of a general (square/rectangle, symmetrical/unsymmetrical, non-singular/singular) matrix and solving systems of Simultaneous Linear Equations (SLE) are formulated and explained. The developed procedures and its associated computer software (under MATLAB [7] computer environment) have been based on “special Cholesky factorization schemes” (for a singular matrix). Test matrices from different fields of applications have been chosen, tested and compared with other existing algorithms. The results of the numerical tests have indicated that the developed procedures are far more efficient than the existing algorithms.展开更多
Modular inverse arithmetic plays an important role in elliptic curve cryptography. Based on the analysis of Montgomery modular inversion algorithm, this paper presents a new dual-field modular inversion algorithm, and...Modular inverse arithmetic plays an important role in elliptic curve cryptography. Based on the analysis of Montgomery modular inversion algorithm, this paper presents a new dual-field modular inversion algorithm, and a novel scalable and unified architecture for Montgomery inverse hardware in finite fields GF(p) and GF(2n) is proposed. Furthermore, this architecture based on the new modular inversion algorithm has been verified by modeling it in Verilog-HDL, and accomplished it under 0.18 μm CMOS technology. The result indicates that our work has better performance and flexibility than other works.展开更多
In order to solve the flexible job shop scheduling problem with variable batches,we propose an improved multiobjective optimization algorithm,which combines the idea of inverse scheduling.First,a flexible job shop pro...In order to solve the flexible job shop scheduling problem with variable batches,we propose an improved multiobjective optimization algorithm,which combines the idea of inverse scheduling.First,a flexible job shop problem with the variable batches scheduling model is formulated.Second,we propose a batch optimization algorithm with inverse scheduling in which the batch size is adjusted by the dynamic feedback batch adjusting method.Moreover,in order to increase the diversity of the population,two methods are developed.One is the threshold to control the neighborhood updating,and the other is the dynamic clustering algorithm to update the population.Finally,a group of experiments are carried out.The results show that the improved multi-objective optimization algorithm can ensure the diversity of Pareto solutions effectively,and has effective performance in solving the flexible job shop scheduling problem with variable batches.展开更多
In this paper,a time-frequency associated multiple signal classification(MUSIC)al-gorithm which is suitable for through-wall detection is proposed.The technology of detecting hu-man targets by through-wall radar can b...In this paper,a time-frequency associated multiple signal classification(MUSIC)al-gorithm which is suitable for through-wall detection is proposed.The technology of detecting hu-man targets by through-wall radar can be used to monitor the status and the location information of human targets behind the wall.However,the detection is out of order when classical MUSIC al-gorithm is applied to estimate the direction of arrival.In order to solve the problem,a time-fre-quency associated MUSIC algorithm suitable for through-wall detection and based on S-band stepped frequency continuous wave(SFCW)radar is researched.By associating inverse fast Fouri-er transform(IFFT)algorithm with MUSIC algorithm,the power enhancement of the target sig-nal is completed according to the distance calculation results in the time domain.Then convert the signal to the frequency domain for direction of arrival(DOA)estimation.The simulations of two-dimensional human target detection in free space and the processing of measured data are com-pleted.By comparing the processing results of the two algorithms on the measured data,accuracy of DOA estimation of proposed algorithm is more than 75%,which is 50%higher than classical MUSIC algorithm.It is verified that the distance and angle of human target can be effectively de-tected via proposed algorithm.展开更多
Fibre reinforced polymer (FRP) composite laminates are now commonly usedin many structural applications, especially in the aerospace industry, where margins ofsafety are kept low in order to minimise weight. Timely de...Fibre reinforced polymer (FRP) composite laminates are now commonly usedin many structural applications, especially in the aerospace industry, where margins ofsafety are kept low in order to minimise weight. Timely detection and assessment ofdamage (in particular delaminations) in composite laminates are therefore critical, as theycan cause loss of structural integrity affecting the safe operation of the composite structures.The current trend is towards implementation of structural health monitoring (SHM)systems which can monitor the structures in situ without down time. In this paper, first, thecurrent available SHM techniques for delamination detection in FRP composites arebriefly reviewed, including acoustic emission, fibre optic sensors, Lamb wave-,impedance- and vibration-based methods. Among different vibration-based methods,frequency monitoring is the simplest to implement, requiring only single pointmeasurement, and is relatively accurate and reliable, thus it becomes the main focus ofpresent paper. A comprehensive review of frequency-based vibration monitoring isconducted in terms of the various aspects of delamination identification in FRPs throughfrequency shifts, including review of theoretical models for free vibration of delaminatedFRP beams, survey of finite element modelling of delaminated composite structures,summary of experimental modal analyses on FRP composites with delaminations, andinverse algorithms for frequency-based delamination assessment. This paper aims to helpthe readers to get an overview of the available SHM techniques for monitoring the integrityof FRP composites, with a special emphasis on delamination assessment throughfrequency-based vibration monitoring.展开更多
Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation(DIC...Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation(DIC) algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss–Newton(IC-GN) algorithm.The performance of this strategy, including accuracy, precision, and computation efficiency, is evaluated through a theoretical and experimental study, using the one with widely employed bicubic interpolation as a benchmark. The global look-up table strategy with cubic B-spline interpolation improves significantly the accuracy of the IC-GN algorithm-based DIC method compared with the one using the bicubic interpolation, at a trivial price of computation efficiency.展开更多
With the increasing of detection ability of passive sonar,the weak signal detection problem in multiple interferences becomes more and more important.In the time/bearing record(TBR) display of sonar detection,when the...With the increasing of detection ability of passive sonar,the weak signal detection problem in multiple interferences becomes more and more important.In the time/bearing record(TBR) display of sonar detection,when there exist traces of multiple interferences,the identification of weak signal is difficult or impossible.The adaptive noise cancellation technique provides the theoretical basis for suppressing strong interferences.But the solution for finding the steady-state optimum filter matrix is quite difficult due to the real time calculation of inverse matrix of input data correlation matrix.The iterative inverse beamforming(IBF) algorithm for solving the optimum filter vector,which is expressed by inverse matrix of the ocean environment data,is derived in this paper,by which,the optimum filter can be eventually expressed as a sum of series simple matrices of constructed from sensor data.Based on the algorithm proposed in this paper,some examples of at sea experiment are provided.The strong interferences are cancelled and the weak signal is emerged,even it didn't appear in the conventional beamforming(CBF) processing.展开更多
Ultrasonic guided waves(UGWs),which propagate throughout the entire thickness of cortical bone,are attractive for the early diagnosis of osteoporosis.However,this is challenging due to the impact of soft tissue and th...Ultrasonic guided waves(UGWs),which propagate throughout the entire thickness of cortical bone,are attractive for the early diagnosis of osteoporosis.However,this is challenging due to the impact of soft tissue and the inherent difficulties related to multiparametric inversion of cortical bone quality factors,such as cortical thickness and bulk wave velocity.Therefore,in this research,a UGW-based multi-parameter inversion algorithm is developed to predict strength-related factors.In simulation,a free plate(cortical bone)and a bilayer plate(soft tissue and cortical bone)are used to validate the proposed method.The inversed cortical thickness(CTh),longitudinal velocity(V_(L))and transverse velocity(V_(T))are in accordance with the true values.Then four bovine cortical bone plates were used in in vitro experiments.Compared with the reference values,the relative errors for cortical thickness were 3.96%,0.83%,2.87%,and 4.25%,respectively.In the in vivo measurements,UGWs are collected from the tibias of 10 volunteers.The theoretical dispersion curves depicted by the estimated parameters(V_(T),V_(L),CTh)match well with the extracted experimental ones.In comparison with dual-energy x-ray absorptiometry,our results show that the estimated transverse velocity and cortical thickness are highly sensitive to osteoporosis.Therefore,these two parameters(CTh and V_(T))of long bones have potential to be used for diagnosis of bone status in clinical applications.展开更多
This paper proposes the efficient model building in active appearance model(AAM) for the rotated face.Finding an exact region of the face is generally difficult due to different shapes and viewpoints.Unlike many paper...This paper proposes the efficient model building in active appearance model(AAM) for the rotated face.Finding an exact region of the face is generally difficult due to different shapes and viewpoints.Unlike many papers about the fitting method of AAM,this paper treats how images are chosen for fitting of the rotated face in modelling process.To solve this problem,databases of facial rotation and expression are selected and models are built using Procrustes method and principal component analysis(PCA).These models are applied in fitting methods like basic AAM fitting,inverse compositional alignment(ICA),project-out ICA,normalization ICA,robust normalization inverse compositional algorithm(RNIC)and efficient robust normalization algorithm(ERN).RNIC and ERN can fit the rotated face in images efficiently.The efficiency of model building is checked using sequence images made by ourselves.展开更多
The distortion of mold plates plays an important role in the formation of surface cracks on continuously cast steel products.To investigate the non-uniform distortion of a mold,a full-scale stress model of the mold wa...The distortion of mold plates plays an important role in the formation of surface cracks on continuously cast steel products.To investigate the non-uniform distortion of a mold,a full-scale stress model of the mold was developed.An inverse algorithm was applied to calculate the heat flux using the temperatures measured by the thermocouples buried inside the mold plates.Based on this,a full-scale,finite-element stress model,including four copper plates,a nickel layer and water slots in different depths,was built to determine the complex mechanical behavior of the continuous casting mold used to produce steel slabs.The heat flux calculated by the inverse algorithm was applied to the stress model to analyze the non-uniform mechanical behavior.The results showed that the stress and distortion distributions of the four copper plates were not symmetrical,which reflected the non-uniform distortion behaviors of copper plates,water slots,nickel layer and the corner region of the mold.The gap between the mold and the slab was increased because of the corner distortion,which was very important for the heat transfer of initial solidifying shell,and it may be a major reason for the slow cooling of the slab corner.展开更多
Effective identification of pollution sources is particularly important for indoor air quality.Accurate estimation of source strength is the basis for source effective identification.This paper proposes an optimizatio...Effective identification of pollution sources is particularly important for indoor air quality.Accurate estimation of source strength is the basis for source effective identification.This paper proposes an optimization method for the deconvolution process in the source strength inverse calculation.In the scheme,the concept of time resolution was defined,and combined with different filtering positions and filtering algorithms.The measures to reduce effects of measurement noise were quantitatively analyzed.Additionally,the performances of nine deconvolution inverse algorithms under experimental and simulated conditions were evaluated and scored.The hybrid algorithms were proposed and compared with single algorithms including Tikhonov regularization and iterative methods.Results showed that for the filtering position and algorithm,Butterworth filtering performed better,and different filtering positions had little effect on the inverse calculation.For the calculation time step,the optimal Tr(time resolution)was 0.667%and 1.33%in the simulation and experiment,respectively.The hybrid algorithms were found to not perform better than the single algorithms,and the SART(simultaneous algebraic reconstruction technique)algorithm from CAT(computer assisted tomography)yielded better performances in the accuracy and stability of source strength identification.The relative errors of the inverse calculation for source strength were typically below 25%using the optimization scheme.展开更多
Introduction:The application of remote-sensing techniques for water quality assessment has become increasingly popular in China.However,existing reviews are often limited to qualitative description and are quite fragm...Introduction:The application of remote-sensing techniques for water quality assessment has become increasingly popular in China.However,existing reviews are often limited to qualitative description and are quite fragmented.Outcomes:We conducted a quantitative systematic review to display current research status and identify the existing challenges and future directions.Our review revealed that the application of remote-sensing techniques in water quality research has expanded dramatically in China,but the spatial distribution is quite uneven.Second,the ground object spectrometer is the most widely applied data source.Water color indicators such as chlorophyll a and suspended solid are the most widely investigated in China.Third,semiempirical method is the most commonly used inversion method.Existing studies rarely considered the anthropogenic factors,which limited the model robustness and its application in humandominated aquatic ecosystems.Discussion and Conclusion:We concluded that,in the past several decades,China has made notable progresses in monitoring and evaluation of water quality using the remote-sensing techniques(especially in inland lakes).We proposed that further improvements would be needed in terms of temporal and spatial coverage,indicator list,the incorporation of human–nature interactions,inversion accuracy,and model generalization.展开更多
Parallel computing techniques have been introduced into digital image correlation(DIC) in recent years and leads to a surge in computation speed. The graphics processing unit(GPU)-based parallel computing demonstrated...Parallel computing techniques have been introduced into digital image correlation(DIC) in recent years and leads to a surge in computation speed. The graphics processing unit(GPU)-based parallel computing demonstrated a surprising effect on accelerating the iterative subpixel DIC, compared with CPU-based parallel computing. In this paper, the performances of the two kinds of parallel computing techniques are compared for the previously proposed path-independent DIC method, in which the initial guess for the inverse compositional Gauss-Newton(IC-GN) algorithm at each point of interest(POI) is estimated through the fast Fourier transform-based cross-correlation(FFT-CC) algorithm. Based on the performance evaluation, a heterogeneous parallel computing(HPC) model is proposed with hybrid mode of parallelisms in order to combine the computing power of GPU and multicore CPU. A scheme of trial computation test is developed to optimize the configuration of the HPC model on a specific computer. The proposed HPC model shows excellent performance on a middle-end desktop computer for real-time subpixel DIC with high resolution of more than 10000 POIs per frame.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.62205280)the Graduate Innovation Foundation of Yantai University(Grant No.GGIFYTU2348).
文摘Herein,a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity.Fractional-order calculus has the inherent advantage of easily jumping out of local extreme values;here,it is introduced into the particle-swarm algorithm to invert the true temperature.An improved adaptive-adjustment mechanism is applied to automatically adjust the current velocity order of the particles and update their velocity and position values,increasing the accuracy of the true temperature values.The results of simulations using the proposed algorithm were compared with three algorithms using typical emissivity models:the internal penalty function algorithm,the optimization function(fmincon)algorithm,and the conventional particle-swarm optimization algorithm.The results show that the proposed algorithm has good accuracy for true-temperature inversion.Actual experimental results from a rocket-motor plume were used to demonstrate that the true-temperature inversion results of this algorithm are in good agreement with the theoretical true-temperature values.
文摘Solving large scale system of Simultaneous Linear Equations (SLE) has been (and continue to be) a major challenging problem for many real-world engineering and science applications. Solving SLE with singular coefficient matrices arises from various engineering and sciences applications [1]-[6]. In this paper, efficient numerical procedures for finding the generalized (or pseudo) inverse of a general (square/rectangle, symmetrical/unsymmetrical, non-singular/singular) matrix and solving systems of Simultaneous Linear Equations (SLE) are formulated and explained. The developed procedures and its associated computer software (under MATLAB [7] computer environment) have been based on “special Cholesky factorization schemes” (for a singular matrix). Test matrices from different fields of applications have been chosen, tested and compared with other existing algorithms. The results of the numerical tests have indicated that the developed procedures are far more efficient than the existing algorithms.
基金Supported by the National High Technology Research and Development Program of China (863 Program) (No. 2008AA01Z103)
文摘Modular inverse arithmetic plays an important role in elliptic curve cryptography. Based on the analysis of Montgomery modular inversion algorithm, this paper presents a new dual-field modular inversion algorithm, and a novel scalable and unified architecture for Montgomery inverse hardware in finite fields GF(p) and GF(2n) is proposed. Furthermore, this architecture based on the new modular inversion algorithm has been verified by modeling it in Verilog-HDL, and accomplished it under 0.18 μm CMOS technology. The result indicates that our work has better performance and flexibility than other works.
基金supported by the National Key R&D Plan(2020YFB1712902)the National Natural Science Foundation of China(52075036).
文摘In order to solve the flexible job shop scheduling problem with variable batches,we propose an improved multiobjective optimization algorithm,which combines the idea of inverse scheduling.First,a flexible job shop problem with the variable batches scheduling model is formulated.Second,we propose a batch optimization algorithm with inverse scheduling in which the batch size is adjusted by the dynamic feedback batch adjusting method.Moreover,in order to increase the diversity of the population,two methods are developed.One is the threshold to control the neighborhood updating,and the other is the dynamic clustering algorithm to update the population.Finally,a group of experiments are carried out.The results show that the improved multi-objective optimization algorithm can ensure the diversity of Pareto solutions effectively,and has effective performance in solving the flexible job shop scheduling problem with variable batches.
文摘In this paper,a time-frequency associated multiple signal classification(MUSIC)al-gorithm which is suitable for through-wall detection is proposed.The technology of detecting hu-man targets by through-wall radar can be used to monitor the status and the location information of human targets behind the wall.However,the detection is out of order when classical MUSIC al-gorithm is applied to estimate the direction of arrival.In order to solve the problem,a time-fre-quency associated MUSIC algorithm suitable for through-wall detection and based on S-band stepped frequency continuous wave(SFCW)radar is researched.By associating inverse fast Fouri-er transform(IFFT)algorithm with MUSIC algorithm,the power enhancement of the target sig-nal is completed according to the distance calculation results in the time domain.Then convert the signal to the frequency domain for direction of arrival(DOA)estimation.The simulations of two-dimensional human target detection in free space and the processing of measured data are com-pleted.By comparing the processing results of the two algorithms on the measured data,accuracy of DOA estimation of proposed algorithm is more than 75%,which is 50%higher than classical MUSIC algorithm.It is verified that the distance and angle of human target can be effectively de-tected via proposed algorithm.
基金supported by National Natural Science Fundsof China (Grant No. 51508118)Natural Science Foundation of Guangdong Province,China (Grant No. 2016A030310261)Science and Technology Planning Project ofGuangdong Province, China (Grant No. 2016B050501004).
文摘Fibre reinforced polymer (FRP) composite laminates are now commonly usedin many structural applications, especially in the aerospace industry, where margins ofsafety are kept low in order to minimise weight. Timely detection and assessment ofdamage (in particular delaminations) in composite laminates are therefore critical, as theycan cause loss of structural integrity affecting the safe operation of the composite structures.The current trend is towards implementation of structural health monitoring (SHM)systems which can monitor the structures in situ without down time. In this paper, first, thecurrent available SHM techniques for delamination detection in FRP composites arebriefly reviewed, including acoustic emission, fibre optic sensors, Lamb wave-,impedance- and vibration-based methods. Among different vibration-based methods,frequency monitoring is the simplest to implement, requiring only single pointmeasurement, and is relatively accurate and reliable, thus it becomes the main focus ofpresent paper. A comprehensive review of frequency-based vibration monitoring isconducted in terms of the various aspects of delamination identification in FRPs throughfrequency shifts, including review of theoretical models for free vibration of delaminatedFRP beams, survey of finite element modelling of delaminated composite structures,summary of experimental modal analyses on FRP composites with delaminations, andinverse algorithms for frequency-based delamination assessment. This paper aims to helpthe readers to get an overview of the available SHM techniques for monitoring the integrityof FRP composites, with a special emphasis on delamination assessment throughfrequency-based vibration monitoring.
基金financially supported by the National Natural Science Foundation of China(11202081,11272124,and 11472109)the State Key Lab of Subtropical Building Science,South China University of Technology(2014ZC17)
文摘Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation(DIC) algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss–Newton(IC-GN) algorithm.The performance of this strategy, including accuracy, precision, and computation efficiency, is evaluated through a theoretical and experimental study, using the one with widely employed bicubic interpolation as a benchmark. The global look-up table strategy with cubic B-spline interpolation improves significantly the accuracy of the IC-GN algorithm-based DIC method compared with the one using the bicubic interpolation, at a trivial price of computation efficiency.
基金supported by the National Natural Science Foundation of China(11304343)
文摘With the increasing of detection ability of passive sonar,the weak signal detection problem in multiple interferences becomes more and more important.In the time/bearing record(TBR) display of sonar detection,when there exist traces of multiple interferences,the identification of weak signal is difficult or impossible.The adaptive noise cancellation technique provides the theoretical basis for suppressing strong interferences.But the solution for finding the steady-state optimum filter matrix is quite difficult due to the real time calculation of inverse matrix of input data correlation matrix.The iterative inverse beamforming(IBF) algorithm for solving the optimum filter vector,which is expressed by inverse matrix of the ocean environment data,is derived in this paper,by which,the optimum filter can be eventually expressed as a sum of series simple matrices of constructed from sensor data.Based on the algorithm proposed in this paper,some examples of at sea experiment are provided.The strong interferences are cancelled and the weak signal is emerged,even it didn't appear in the conventional beamforming(CBF) processing.
基金the National Natural Science Foundation of China(Grant No.12034005)in part by the Program of Shanghai Academic Research Leader(Grant No.19XD1400500)in part by the China Postdoctoral Science Foundation(Grant No.2019M661334)。
文摘Ultrasonic guided waves(UGWs),which propagate throughout the entire thickness of cortical bone,are attractive for the early diagnosis of osteoporosis.However,this is challenging due to the impact of soft tissue and the inherent difficulties related to multiparametric inversion of cortical bone quality factors,such as cortical thickness and bulk wave velocity.Therefore,in this research,a UGW-based multi-parameter inversion algorithm is developed to predict strength-related factors.In simulation,a free plate(cortical bone)and a bilayer plate(soft tissue and cortical bone)are used to validate the proposed method.The inversed cortical thickness(CTh),longitudinal velocity(V_(L))and transverse velocity(V_(T))are in accordance with the true values.Then four bovine cortical bone plates were used in in vitro experiments.Compared with the reference values,the relative errors for cortical thickness were 3.96%,0.83%,2.87%,and 4.25%,respectively.In the in vivo measurements,UGWs are collected from the tibias of 10 volunteers.The theoretical dispersion curves depicted by the estimated parameters(V_(T),V_(L),CTh)match well with the extracted experimental ones.In comparison with dual-energy x-ray absorptiometry,our results show that the estimated transverse velocity and cortical thickness are highly sensitive to osteoporosis.Therefore,these two parameters(CTh and V_(T))of long bones have potential to be used for diagnosis of bone status in clinical applications.
基金Next-Generation Information Computing Development Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(No.2012M3C4A7032182)The MSIP(Ministry of Science,ICT&Future Planning),Korea,under the ITRC(Information Technology Research Center)support program(NIPA-2013-H0301-13-2006)supervised by the NIPA(National IT Industry Promotion Agency)
文摘This paper proposes the efficient model building in active appearance model(AAM) for the rotated face.Finding an exact region of the face is generally difficult due to different shapes and viewpoints.Unlike many papers about the fitting method of AAM,this paper treats how images are chosen for fitting of the rotated face in modelling process.To solve this problem,databases of facial rotation and expression are selected and models are built using Procrustes method and principal component analysis(PCA).These models are applied in fitting methods like basic AAM fitting,inverse compositional alignment(ICA),project-out ICA,normalization ICA,robust normalization inverse compositional algorithm(RNIC)and efficient robust normalization algorithm(ERN).RNIC and ERN can fit the rotated face in images efficiently.The efficiency of model building is checked using sequence images made by ourselves.
基金Item Sponsored by National Natural Science Foundation of China(51474047,51004012)China Postdoctoral Science Foundation(2012M520621,2013T60511)Fundamental Research Funds for the Central Universities of China
文摘The distortion of mold plates plays an important role in the formation of surface cracks on continuously cast steel products.To investigate the non-uniform distortion of a mold,a full-scale stress model of the mold was developed.An inverse algorithm was applied to calculate the heat flux using the temperatures measured by the thermocouples buried inside the mold plates.Based on this,a full-scale,finite-element stress model,including four copper plates,a nickel layer and water slots in different depths,was built to determine the complex mechanical behavior of the continuous casting mold used to produce steel slabs.The heat flux calculated by the inverse algorithm was applied to the stress model to analyze the non-uniform mechanical behavior.The results showed that the stress and distortion distributions of the four copper plates were not symmetrical,which reflected the non-uniform distortion behaviors of copper plates,water slots,nickel layer and the corner region of the mold.The gap between the mold and the slab was increased because of the corner distortion,which was very important for the heat transfer of initial solidifying shell,and it may be a major reason for the slow cooling of the slab corner.
基金supported by the National Natural Science Foundation of China(No.51708286)the Natural Science Foundation of Jiangsu Province(No.BK20180701)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX20-0325).
文摘Effective identification of pollution sources is particularly important for indoor air quality.Accurate estimation of source strength is the basis for source effective identification.This paper proposes an optimization method for the deconvolution process in the source strength inverse calculation.In the scheme,the concept of time resolution was defined,and combined with different filtering positions and filtering algorithms.The measures to reduce effects of measurement noise were quantitatively analyzed.Additionally,the performances of nine deconvolution inverse algorithms under experimental and simulated conditions were evaluated and scored.The hybrid algorithms were proposed and compared with single algorithms including Tikhonov regularization and iterative methods.Results showed that for the filtering position and algorithm,Butterworth filtering performed better,and different filtering positions had little effect on the inverse calculation.For the calculation time step,the optimal Tr(time resolution)was 0.667%and 1.33%in the simulation and experiment,respectively.The hybrid algorithms were found to not perform better than the single algorithms,and the SART(simultaneous algebraic reconstruction technique)algorithm from CAT(computer assisted tomography)yielded better performances in the accuracy and stability of source strength identification.The relative errors of the inverse calculation for source strength were typically below 25%using the optimization scheme.
基金supported by the National Natural Science Foundation of China(Grant Nos.11972013 and 12272145)the Ministry of Science and Technology of China(Grant No.2018YFF01014200).
基金This work was supported by the National Natural Science Foundation of China[71673247]the Outstanding Youth Fund of Zhejiang Province[LR18D010001]+1 种基金Ministry of Science and Technology of China[2016YFC0503404]Fundamental Research Funds for the Central Universities[2017QNA6010].
文摘Introduction:The application of remote-sensing techniques for water quality assessment has become increasingly popular in China.However,existing reviews are often limited to qualitative description and are quite fragmented.Outcomes:We conducted a quantitative systematic review to display current research status and identify the existing challenges and future directions.Our review revealed that the application of remote-sensing techniques in water quality research has expanded dramatically in China,but the spatial distribution is quite uneven.Second,the ground object spectrometer is the most widely applied data source.Water color indicators such as chlorophyll a and suspended solid are the most widely investigated in China.Third,semiempirical method is the most commonly used inversion method.Existing studies rarely considered the anthropogenic factors,which limited the model robustness and its application in humandominated aquatic ecosystems.Discussion and Conclusion:We concluded that,in the past several decades,China has made notable progresses in monitoring and evaluation of water quality using the remote-sensing techniques(especially in inland lakes).We proposed that further improvements would be needed in terms of temporal and spatial coverage,indicator list,the incorporation of human–nature interactions,inversion accuracy,and model generalization.
基金supported by the National Natural Science Foundation of China(Grant Nos.11772131,11772132,11772134&11472109)the Natural Science Foundation of Guangdong Province,China(Grant Nos.2015A030308017,2015A030311046&2015B010131009)+2 种基金the Opening fund of State Key Laboratory of Nonlinear Mechanics(LNM)CASthe State Key Lab of Subtropical Building Science,South China University of Technology(Grant Nos.2014ZC17&2017ZD096)
文摘Parallel computing techniques have been introduced into digital image correlation(DIC) in recent years and leads to a surge in computation speed. The graphics processing unit(GPU)-based parallel computing demonstrated a surprising effect on accelerating the iterative subpixel DIC, compared with CPU-based parallel computing. In this paper, the performances of the two kinds of parallel computing techniques are compared for the previously proposed path-independent DIC method, in which the initial guess for the inverse compositional Gauss-Newton(IC-GN) algorithm at each point of interest(POI) is estimated through the fast Fourier transform-based cross-correlation(FFT-CC) algorithm. Based on the performance evaluation, a heterogeneous parallel computing(HPC) model is proposed with hybrid mode of parallelisms in order to combine the computing power of GPU and multicore CPU. A scheme of trial computation test is developed to optimize the configuration of the HPC model on a specific computer. The proposed HPC model shows excellent performance on a middle-end desktop computer for real-time subpixel DIC with high resolution of more than 10000 POIs per frame.
