In this paper, we proposed a novel resolution criterion（improved calibrated normalized resolution product, r＊＇） to evaluate separation quality of fingerprints. By comparing with the calibrated normalized resolutio...In this paper, we proposed a novel resolution criterion（improved calibrated normalized resolution product, r＊＇） to evaluate separation quality of fingerprints. By comparing with the calibrated normalized resolution product（r＊） and the hierarchical chromatographic response function（HCRF）, the validity of this criterion was demonstrated by experimental chromatograms. The soy isoflavone extract was selected as the analytical object. The initial and end percentages of methanol and elution time affecting gradient elution were tested by orthogonal design. The final optimized conditions were as follows. It was detected by UV absorbance at 254 nm, column temperature was maintained at 36 oC, solvent A was 0.1%（v/v） acetic acid, solvent B was methanol, gradient elution was from 34% to 65% B in a linear gradient in 25 min, and the flow-rate was set at 1.0 m L/min. In addition, the main ingredients of the soy isoflavone extract were confirmed by LC-ESI/MS.展开更多
This paper considers the fundamental channel estimation problem for the multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM)system in the presence of multi-cell interference.Specificall...This paper considers the fundamental channel estimation problem for the multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM)system in the presence of multi-cell interference.Specifically,this paper focuses on both channel modelling and receiver design for interference estimation and mitigation.We propose a delay-calibrated block-wise linear model,which extracts the delay of the dominant tap of each interference as a key parameter and approximates the residual channel coefficients by the recently developed blockwise linear model.Based on the delay-calibrated block-wise linear model and the angle-domain channel sparsity,we further conceive a message passing algorithm to solve the channel estimation problem.Numerical results demonstrate the superior performance of the proposed algorithm over the state-of-the-art algorithms.展开更多
Minor errors in the spoil deposition process,such as placing stronger materials with higher shear strength over weaker ones,can lead to potential dump failure.Irregular deposition and inadequate compaction complicate ...Minor errors in the spoil deposition process,such as placing stronger materials with higher shear strength over weaker ones,can lead to potential dump failure.Irregular deposition and inadequate compaction complicate coal spoil behaviour,neces-sitating a robust methodology for temporal monitoring.This study explores using unmanned aerial vehicles(UAV)equipped with red-green-blue(RGB)sensors for efficient data acquisition.Despite their prevalence,raw UAV data exhibit temporal inconsistency,hindering accurate assessments of changes over time which could be attributed to radiometric errors.To this end,the study introduces an empirical line calibration with invariant targets(ELC-IT),for precise calibration across diverse scenes,particularly in the context of UAV imagery used to monitor the evolving nature of spoil dumps.To evaluate the effec-tiveness of this calibration approach,accuracy assessment of an object-based classification is conducted on both calibrated and uncalibrated data.This classification involves several steps:performing segmentation,carrying out feature extraction,and integrating the extracted features and ground truth labels collected over the time period of UAV image capture into machine learning pipelines.Calibrated RGB data exhibit a substantial performance advantage,achieving a 90.7%overall accuracy for spoil pile classification using ensemble(subspace discriminant),representing a noteworthy 7%improvement compared to classifying uncalibrated data.The study highlights the critical role of data calibration in optimising UAV effectiveness for spatio-temporal mine dump monitoring.These findings play a crucial role in informing and refining sustainable management practices within the domain of mine waste management.展开更多
Objective Calibrated Automated Thrombogram（CAT） is a test to monitor the generation of thrombin. It can be described by four parameters： lag time, peak thrombin, endogenous thrombin potential （ETP） and time to pe...Objective Calibrated Automated Thrombogram（CAT） is a test to monitor the generation of thrombin. It can be described by four parameters： lag time, peak thrombin, endogenous thrombin potential （ETP） and time to peak （ttPeak）. This study aims to determine the normal ranges of CAT parameters in Chinese, and evaluate whether thrombin generation is correlated with the concentration of heparin/Iow molecular weight heparin. Methods Plasma from 120 healthy subjects were collected to determine the normal rangea of CAT parameters in Chinese. Normal plasma pool （NPP, n=25） spiked with different concentrations of heparin or enoxaparin were used to detecte CAT parameters. The overall and age specific normal ranges of CAT parameters were calculated using descriptive statistics method with mean＋-2SD. The correlation between CAT parameters and age or concentrations of heparin, enoxaparin were analyzed with linear regression model. Results The normal ranges for lag time, peak thrombin, ETP, ttPeak in the subjects were 3.648＋2.465 min, 367.39＋151.93 nmol/L, 2277＋_1030 nmol/L.min and 6.372＋_4.280 min respectively. Age was linearly correlated with lag time （r=-0.6583, P〈0.0002）, peak thrombin （r=0.4863, P〈0.0002）, ETP （r=0.3608, P〈0.0014） and ttPeak （r=-0.6323, P〈0.0002）. The values of ETP/peak ratio were linearly correlated with concentrations of heparin. Conclusion The normal ranges of four CAT parameters for Chinese were determined. CAT parameters are associated with age. ETP/peak ratio could be used to monitor the process of anticoagulation therapy.展开更多
In this paper,we focus on the problem of joint estimation of DOA,power and polarization angle from sparse reconstruction perspective with array gain-phase errors,where a partly calibrated cocentered orthogonal loop an...In this paper,we focus on the problem of joint estimation of DOA,power and polarization angle from sparse reconstruction perspective with array gain-phase errors,where a partly calibrated cocentered orthogonal loop and dipole(COLD)array is utilized.In detailed implementations,we first combine the output of loop and dipole in second-order statistics domain to receive the source signals completely,and then we use continuous multiplication operator to achieve gain-phase errors calibration.After compensating the gain-phase errors,we construct a log-penalty-based optimization problem to approximate`0 norm and further exploit difference of convex(DC)functions decomposition to achieve DOA.With the aid of the estimated DOAs,the power and polarization angle estimation are obtained by the least squares(LS)method.By conducting numerical simulations,we show the effectiveness and superiorities of the proposed method.展开更多
Long term stability is the main factor that influences the minimum detectable signal of microwave radiometers. Two new types of microwave radiometer were studied: a computer gain compensative microwave radiometer and ...Long term stability is the main factor that influences the minimum detectable signal of microwave radiometers. Two new types of microwave radiometer were studied: a computer gain compensative microwave radiometer and a real-time calibrated microwave radiometer. The long term stability of both designs was optimal because they were insensitive to system gain fluctuations. The continuous calibrated microwave radiometer was also insensitive to system noise fluctuations. The minimum detectable signals were 0.13 and 0.19K respectively under an integration time of 0.6s.展开更多
Accurate and reliable river flow information is critical to planning and management for sustainable water resources utilization. Most of engineering activities related to hydrologic designs, flood, drought, reservoirs...Accurate and reliable river flow information is critical to planning and management for sustainable water resources utilization. Most of engineering activities related to hydrologic designs, flood, drought, reservoirs and their operations are heavily dependent on the river flow information derived from river rating curve. The rating curve for a given river section is normally developed from a set of direct stage-discharge measurements for different periods. This involves considerable labour, risk and resources, and presupposes a complex and extensive measuring survey. Extrapolating the rating curve beyond the measured range, as common in many cases, is fraught with errors and uncertainties, due to the complex hydraulic behaviour of the surface water profile in transition from section, channel, downstream and flood plain controls which are often poorly understood with direct measurements. Hydraulic modeling has recently emerged as one of the more promising methods to efficiently develop accurate rating curves for a river section with simple or complex hydraulic structures and conditions. This paper explores the use of a Hydraulic Engineering Center-River Analysis System (HEC-RAS) model to review and develop river rating curves for three hydrometric stations on two rivers in Kwale, coastal Kenya. The HEC-RAS models were set up based on topographical (cross section and longitudinal) survey data for the reaches and engineering drawings for the hydraulic structures commonly used as section controls for flow measurement. The model was calibrated under unsteady state conditions against measured stage-discharge data which were captured using a Velocity Current Meter (Valeport) and an Acoustic Doppler Current Profiler (ADCP) for both low and high flow. The rating curves were extracted from model results and the uncertainty associated with each rating curve analyzed. The results obtained by the HEC-RAS model were satisfactory and deemed acceptable for predicting discharge across the stage range at each river section.展开更多
Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks,provide safe and smooth rides,and reduce the maintenance frequency.In this paper,the elastic performance of a ...Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks,provide safe and smooth rides,and reduce the maintenance frequency.In this paper,the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in Abaqus.It is then compared to the performance of a ballasted track.First,slab and ballasted track models are developed to replicate the full-scale testing of track sections.Once the models are calibrated with the experimental results,the novel slab model is developed and compared against the calibrated slab track results.The slab and ballasted track models are then extended to create linear dynamic models,considering the track geodynamics,and simulating train passages at various speeds,for which the Ledsgard documented case was used to validate the models.Trains travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil,considering the issues associated with critical speeds.Various train loading methods are discussed,and the most practical approach is retained and described.Moreover,correlations are made between the geotechnical parameters of modern high-speed rail and conventional standards.It is found that considering the same ground condition,the slab track deflections are considerably smaller than those of the ballasted track at high speeds,while they show similar behaviour at low speeds.展开更多
From the perspective of error compensation in the sampling process, a digital calibration algorithm was studied for the processing of spectral data in dual-comb spectroscopy. In this algorithm, dynamic adaptation to p...From the perspective of error compensation in the sampling process, a digital calibration algorithm was studied for the processing of spectral data in dual-comb spectroscopy. In this algorithm, dynamic adaptation to phase fluctuations maintained constant measurement results of spectral line positions and intensities. A mode-resolved broadband absorption spectrum was obtained over the full-spectral range of the comb with a Hertz linewidth of radio frequency comb mode.The measured spectrum spanned over 10 THz, which covered the multiplexed absorption regions of mixed gases, such as CO2 and N2 O. The calibrated interferograms were also capable of direct coherent averaging in the time domain. The transmittance obtained deviated from the theoretical calculation by no more than 2% in the whole spectral span.展开更多
Variance is one of the most vital measures of dispersion widely employed in practical aspects.A commonly used approach for variance estimation is the traditional method of moments that is strongly influenced by the pr...Variance is one of the most vital measures of dispersion widely employed in practical aspects.A commonly used approach for variance estimation is the traditional method of moments that is strongly influenced by the presence of extreme values,and thus its results cannot be relied on.Finding momentum from Koyuncu’s recent work,the present paper focuses first on proposing two classes of variance estimators based on linear moments(L-moments),and then employing them with auxiliary data under double stratified sampling to introduce a new class of calibration variance estimators using important properties of L-moments(L-location,L-cv,L-variance).Three populations are taken into account to assess the efficiency of the new estimators.The first and second populations are concerned with artificial data,and the third populations is concerned with real data.The percentage relative efficiency of the proposed estimators over existing ones is evaluated.In the presence of extreme values,our findings depict the superiority and high efficiency of the proposed classes over traditional classes.Hence,when auxiliary data is available along with extreme values,the proposed classes of estimators may be implemented in an extensive variety of sampling surveys.展开更多
Evapotranspiration(ET)is the key to the water cycle process and an important factor for studying near-surface water and heat balance.Accurately estimating ET is significant for hydrology,meteorology,ecology,agricultur...Evapotranspiration(ET)is the key to the water cycle process and an important factor for studying near-surface water and heat balance.Accurately estimating ET is significant for hydrology,meteorology,ecology,agriculture,etc..This paper simulates ET in the Madu River Basin of Three Gorges Reservoir Area of China during 2009-2018 based on the Soil and Water Assessment Tool(SWAT)model,which was calibrated and validated using the MODIS(Moderate-resolution Imaging Spectroradiometer)/Terra Net ET 8-Day L4 Global 500 m SIN Grid(MOD16A2)dataset and measured ET.Two calibration strategies(lumped calibration(LC)and spatially distributed calibration(SDC))were used.The basin was divided into 34 sub-basins,and the coefficient of determination(R^(2))and NashSutcliffe efficiency coefficient(NSE)of each sub-basin were greater than 0.6 in both the calibration and validation periods.The R2 and NSE were higher in the validation period than those in the calibration period.Compared with the measured ET,the accuracy of the model on the daily scale is:R^(2)=0.704 and NSE=0.759(SDC results).The model simulation accuracy of LC and SDC for the sub-basin scale was R^(2)=0.857,R^(2)=0.862(monthly)and R^(2)=0.227,R^(2)=0.404(annually),respectively;for the whole basin scale was R^(2)=0.902,R^(2)=0.900(monthly)and R^(2)=0.507 and R^(2)=0.519(annually),respectively.The model performed acceptably,and SDC performed the best,indicating that remote sensing data can be used for SWAT model calibration.During 2009-2018,ET generally increased in the Madu River Basin(SDC results,7.21 mm/yr),with a multiyear average value of 734.37 mm/yr.The annual ET change rate for the sub-basin was relatively low upstream and downstream.The linear correlation analysis between ET and meteorological factors shows that on the monthly scale,precipitation,solar radiation and daily maximum and minimum temperature were significantly correlated with ET;annually,solar radiation and wind speed had a moderate correlation with ET.The correlation between maximum temperature and ET is best on the monthly scale(Pearson correlation coefficient R=0.945),which may means that the increasing ET originating from increasing temperature(global warming).However,the sub-basins near Shennongjia Nature Reserve that are in upstream have a negative ET change rate,which means that ET decreases in these sub-basins,indicating that the’Evaporation Paradox’exists in these sub-basins.This study explored the potential of remote-sensing-based ET data for hydrological model calibration and provides a decision-making reference for water resource management in the Madu River Basin.展开更多
Holographic near-eye augmented reality(AR)displays featuring tilted inbound/outbound angles on compact optical combiners hold significant potential yet often struggle to deliver satisfying image quality.This is primar...Holographic near-eye augmented reality(AR)displays featuring tilted inbound/outbound angles on compact optical combiners hold significant potential yet often struggle to deliver satisfying image quality.This is primarily attributed to two reasons:the lack of a robust off-axis-supported phase hologram generation algorithm;and the suboptimal performance of ill-tuned hardware parts such as imperfect holographic optical elements(HOEs).To address these issues,we incorporate a gradient descent-based phase retrieval algorithm with spectrum remapping,allowing for precise hologram generation with wave propagation between nonparallel planes.Further,we apply a camera-calibrated propagation scheme to iteratively optimize holograms,mitigating imperfections arising from the defects in the HOE fabrication process and other hardware parts,thereby significantly lifting the holographic image quality.We build an off-axis holographic near-eye display prototype using off-the-shelf light engine parts and a customized full-color HOE,demonstrating state-of-the-art virtual reality and AR display results.展开更多
European directives advocate for end-users to be aware of their energy consumption.However,individual energy monitoring tools,such as energy meters or cost allocators,are not always affordable or technically feasible ...European directives advocate for end-users to be aware of their energy consumption.However,individual energy monitoring tools,such as energy meters or cost allocators,are not always affordable or technically feasible to install.Therefore,the development of virtual tools that enable the study of energy consumption in existing buildings is necessary.Virtual sensors,particularly based on white-box models,offer the opportunity to recreate these behaviours.When calibrated with measured data,white-box models,which incorporate detailed building physics,become increasingly valuable for designing energy-efficient buildings.This research explores a novel approach to identifying building’s load period directly from energy data generated by these calibrated models.The volume of data generated by white-box models can be overwhelming for visual analysis,but the hypothesis here is that analysing this data through clustering techniques can reveal patterns related to occupant behaviour and operational schedules.By feeding indoor temperature data into the calibrated model and analysing the resulting energy outputs,the research proposes a method to identify the heating,ventilation and air conditioning(HVAC)system operation schedule,free oscillation periods and non-recurrent events.Validation is achieved by comparing the identified periods with actual measured data.This methodology enables the development of a virtual sensor for cost allocation,which minimises the need for physical sensor deployment while complying with European Union directives.The research not only demonstrates high accuracy but also the potential to outperform measured schedule.This suggests the ability of the method to identify missing sensor data or other factors affecting temperature curves,enabling fault detection and diagnostics(FDD).Consequently,this opens doors for setting optimised operation schedules that balance energy efficiency with occupant comfort.展开更多
The integration of near-infrared genetically encoded reporters(NIR-GERs)with photoacoustic(PA)imaging enables visualizing deep-seated functions of specific cell populations at high resolution,though the imaging depth ...The integration of near-infrared genetically encoded reporters(NIR-GERs)with photoacoustic(PA)imaging enables visualizing deep-seated functions of specific cell populations at high resolution,though the imaging depth is primarily constrained by reporters’PA response intensity.Directed evolution can optimize NIR-GERs’performance for PA imaging,yet precise quantifying of PA responses in mutant proteins expressed in E.coli colonies across iterative rounds poses challenges to the imaging speed and quantification capabilities of the screening platforms.Here,we present self-calibrated photoacoustic screening(SCAPAS),an imaging-based platform that can detect samples in parallel within 5 s(equivalent to 50 ms per colony),achieving a considerable quantification accuracy of approximately 2.8%and a quantification precision of about 6.47%.SCAPAS incorporates co-expressed reference proteins in sample preparation and employs a ring transducer array with switchable illumination for rapid,wide-field dual-wavelength PA imaging,enabling precisely calculating the PA response using the self-calibration method.Numerical simulations validated the image optimization strategy,quantification process,and noise robustness.Tests with co-expression samples confirmed SCAPAS’s superior screening speed and quantification capabilities.We believe that SCAPAS will facilitate the development of novel NIR-GERs suitable for PA imaging and has the potential to significantly impact the advancement of PA probes and molecular imaging.展开更多
Adversarial approaches,which intentionally challenge machine learning models by generating difficult examples,are increasingly being adopted to improve machine learning interatomic potentials(MLIPs).While already prov...Adversarial approaches,which intentionally challenge machine learning models by generating difficult examples,are increasingly being adopted to improve machine learning interatomic potentials(MLIPs).While already providing great practical value,little is known about the actual prediction errors of MLIPs on adversarial structures and whether these errors can be controlled.We propose the Calibrated Adversarial Geometry Optimization(CAGO)algorithm to discover adversarial structures with userassigned errors.Through uncertainty calibration,the estimated uncertainty of MLIPs is unified with real errors.By performing geometry optimization for calibrated uncertainty,we reach adversarial structures with the user-assigned target MLIP prediction error.Integrating with active learning pipelines,we benchmark CAGO,demonstrating stable MLIPs that systematically converge structural,dynamical,and thermodynamical properties for liquid water and water adsorption in a metal-organic framework within only hundreds of training structures,where previously many thousands were typically required.展开更多
Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry.A novel self-calibrated global rainbow refractometry system base...Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry.A novel self-calibrated global rainbow refractometry system based on illumination by two lasers of different wavelengths is proposed.The angular calibration and refractive index measurement of two wavelengths can be completed simultaneously without extra measurement devices.The numerical and experimental results show the feasibility and high precision of the self-calibration method,which enables the rainbow refractometry to be implemented in a more powerful and convenient way.The self-calibrated rainbow system is successfully applied to measure the refractive indices of ethanol-water solutions with volume concentrations of 10% to 60%.展开更多
We report a wavelength and power monitoring system based on a scanning MEMS filter as wavelength discriminator and a near threshold-biased Fabry-Perot diode laser as wavelength reference. This system is capable of mon...We report a wavelength and power monitoring system based on a scanning MEMS filter as wavelength discriminator and a near threshold-biased Fabry-Perot diode laser as wavelength reference. This system is capable of monitoring 250 channels of DWDM signal at 25 GHz ITU Grid with an error of less than ±8 pm.展开更多
LiDAR and camera are two of the most common sensors used in the fields of robot perception,autonomous driving,augmented reality,and virtual reality,where these sensors are widely used to perform various tasks such as ...LiDAR and camera are two of the most common sensors used in the fields of robot perception,autonomous driving,augmented reality,and virtual reality,where these sensors are widely used to perform various tasks such as odometry estimation and 3D reconstruction.Fusing the information from these two sensors can significantly increase the robustness and accuracy of these perception tasks.The extrinsic calibration between cameras and LiDAR is a fundamental prerequisite for multimodal systems.Recently,extensive studies have been conducted on the calibration of extrinsic parameters.Although several calibration methods facilitate sensor fusion,a comprehensive summary for researchers and,especially,non-expert users is lacking.Thus,we present an overview of extrinsic calibration and discuss diverse calibration methods from the perspective of calibration system design.Based on the calibration information sources,this study classifies these methods as target-based or targetless.For each type of calibration method,further classification was performed according to the diverse types of features or constraints used in the calibration process,and their detailed implementations and key characteristics were introduced.Thereafter,calibration-accuracy evaluation methods are presented.Finally,we comprehensively compare the advantages and disadvantages of each calibration method and suggest directions for practical applications and future research.展开更多
Eucalyptus(Eucalyptus camaldulensis Dehnh.)is an important exotic species in northern Nigeria commonly used for poles and timber.Sustainable management of this resource would require quantifying its volume.Stem taper ...Eucalyptus(Eucalyptus camaldulensis Dehnh.)is an important exotic species in northern Nigeria commonly used for poles and timber.Sustainable management of this resource would require quantifying its volume.Stem taper equations are one of the main and most efficient methods for estimating stem volume to any merchantable limit of a species.There is currently no taper equation for Eucalyptus species in Nigeria.Therefore,this study developed taper equations for E.camaldulensis in northern Nigeria.Data for this study were obtained from a private plantation in Jalingo Local Government Area,Taraba State,Nigeria.68 trees were felled and sectioned into 1-m bolt across the stem to a merchantable limit of 5 cm,which were used as the fitting dataset.An additional 22 trees were felled and used to validate the taper equations for stem volume estimation.Seven taper equations were initially fitted to the dataset using nonlinear least squares.The best taper equation was then refitted using a nonlinear mixed-effects approach and calibrated using diameters of one to five sections from the butt end.The taper equations were numerically integrated to obtain the stem volume,which was compared with empirical volume equations.The result shows that the Kozak(Can J For Res 27(5):619-629.10.1139/x97-011,1997)equation,which included eight parameters,provided the best fit for predicting section diameters for under and over bark.The mixed-effects taper equation(NLME-TE)explained most stem diameter variations in the fitting dataset(pseudo-R2:0.986-0.987;RMSE:0.547-0.578 cm)without substantial residual trends.The validation showed that the prediction accuracy of the integrated NLME-TE improved as the number of sectional diameter measurements increased,with at least a 35%reduction in volume estimate error.For practical implementation,two calibration sectional diameter measurements taken from the butt end per tree are recommended.This approach would reduce measurement effort and cost while improving model performance.展开更多
In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorit...In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorithm under communication constraints to achieve accurate system states of the interested system.An output-based event-triggered scheme is first employed to alleviate transmission burden.Accounting for the limited-communication-induced measurement bias,a novel bias calibration algorithm following the Kalman filtering line is developed to restrain the effect of the measurement bias on system estimation,thereby achieving accurate system state estimates.Subsequently,the Field Programmable Gate Array(FPGA)implementation of the proposed algorithm is also realized with the hope of providing fast bias calibration in practical scenarios.A simulation about a numerical example and a practical example(for gyroscope’s angular velocity bias calibration)on MATLAB is provided to demonstrate the feasibility and effectiveness of the proposed algorithm.展开更多
基金National Higher-Education Institution General Research and Development Funding(Grant No.JKP2011010)
文摘In this paper, we proposed a novel resolution criterion（improved calibrated normalized resolution product, r＊＇） to evaluate separation quality of fingerprints. By comparing with the calibrated normalized resolution product（r＊） and the hierarchical chromatographic response function（HCRF）, the validity of this criterion was demonstrated by experimental chromatograms. The soy isoflavone extract was selected as the analytical object. The initial and end percentages of methanol and elution time affecting gradient elution were tested by orthogonal design. The final optimized conditions were as follows. It was detected by UV absorbance at 254 nm, column temperature was maintained at 36 oC, solvent A was 0.1%（v/v） acetic acid, solvent B was methanol, gradient elution was from 34% to 65% B in a linear gradient in 25 min, and the flow-rate was set at 1.0 m L/min. In addition, the main ingredients of the soy isoflavone extract were confirmed by LC-ESI/MS.
基金supported in part by the National Key Research and Development Program of China under Grant 2020YFB1804800。
文摘This paper considers the fundamental channel estimation problem for the multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM)system in the presence of multi-cell interference.Specifically,this paper focuses on both channel modelling and receiver design for interference estimation and mitigation.We propose a delay-calibrated block-wise linear model,which extracts the delay of the dominant tap of each interference as a key parameter and approximates the residual channel coefficients by the recently developed blockwise linear model.Based on the delay-calibrated block-wise linear model and the angle-domain channel sparsity,we further conceive a message passing algorithm to solve the channel estimation problem.Numerical results demonstrate the superior performance of the proposed algorithm over the state-of-the-art algorithms.
基金supported by the Australian Coal Industry's Research Program(ACARP)(C29048).
文摘Minor errors in the spoil deposition process,such as placing stronger materials with higher shear strength over weaker ones,can lead to potential dump failure.Irregular deposition and inadequate compaction complicate coal spoil behaviour,neces-sitating a robust methodology for temporal monitoring.This study explores using unmanned aerial vehicles(UAV)equipped with red-green-blue(RGB)sensors for efficient data acquisition.Despite their prevalence,raw UAV data exhibit temporal inconsistency,hindering accurate assessments of changes over time which could be attributed to radiometric errors.To this end,the study introduces an empirical line calibration with invariant targets(ELC-IT),for precise calibration across diverse scenes,particularly in the context of UAV imagery used to monitor the evolving nature of spoil dumps.To evaluate the effec-tiveness of this calibration approach,accuracy assessment of an object-based classification is conducted on both calibrated and uncalibrated data.This classification involves several steps:performing segmentation,carrying out feature extraction,and integrating the extracted features and ground truth labels collected over the time period of UAV image capture into machine learning pipelines.Calibrated RGB data exhibit a substantial performance advantage,achieving a 90.7%overall accuracy for spoil pile classification using ensemble(subspace discriminant),representing a noteworthy 7%improvement compared to classifying uncalibrated data.The study highlights the critical role of data calibration in optimising UAV effectiveness for spatio-temporal mine dump monitoring.These findings play a crucial role in informing and refining sustainable management practices within the domain of mine waste management.
基金supported by grant from the Ministry of Education of China(grant No.20110001120088)
文摘Objective Calibrated Automated Thrombogram（CAT） is a test to monitor the generation of thrombin. It can be described by four parameters： lag time, peak thrombin, endogenous thrombin potential （ETP） and time to peak （ttPeak）. This study aims to determine the normal ranges of CAT parameters in Chinese, and evaluate whether thrombin generation is correlated with the concentration of heparin/Iow molecular weight heparin. Methods Plasma from 120 healthy subjects were collected to determine the normal rangea of CAT parameters in Chinese. Normal plasma pool （NPP, n=25） spiked with different concentrations of heparin or enoxaparin were used to detecte CAT parameters. The overall and age specific normal ranges of CAT parameters were calculated using descriptive statistics method with mean＋-2SD. The correlation between CAT parameters and age or concentrations of heparin, enoxaparin were analyzed with linear regression model. Results The normal ranges for lag time, peak thrombin, ETP, ttPeak in the subjects were 3.648＋2.465 min, 367.39＋151.93 nmol/L, 2277＋_1030 nmol/L.min and 6.372＋_4.280 min respectively. Age was linearly correlated with lag time （r=-0.6583, P〈0.0002）, peak thrombin （r=0.4863, P〈0.0002）, ETP （r=0.3608, P〈0.0014） and ttPeak （r=-0.6323, P〈0.0002）. The values of ETP/peak ratio were linearly correlated with concentrations of heparin. Conclusion The normal ranges of four CAT parameters for Chinese were determined. CAT parameters are associated with age. ETP/peak ratio could be used to monitor the process of anticoagulation therapy.
基金the National Natural Science Foundation of China under Grant 61171137.
文摘In this paper,we focus on the problem of joint estimation of DOA,power and polarization angle from sparse reconstruction perspective with array gain-phase errors,where a partly calibrated cocentered orthogonal loop and dipole(COLD)array is utilized.In detailed implementations,we first combine the output of loop and dipole in second-order statistics domain to receive the source signals completely,and then we use continuous multiplication operator to achieve gain-phase errors calibration.After compensating the gain-phase errors,we construct a log-penalty-based optimization problem to approximate`0 norm and further exploit difference of convex(DC)functions decomposition to achieve DOA.With the aid of the estimated DOAs,the power and polarization angle estimation are obtained by the least squares(LS)method.By conducting numerical simulations,we show the effectiveness and superiorities of the proposed method.
文摘Long term stability is the main factor that influences the minimum detectable signal of microwave radiometers. Two new types of microwave radiometer were studied: a computer gain compensative microwave radiometer and a real-time calibrated microwave radiometer. The long term stability of both designs was optimal because they were insensitive to system gain fluctuations. The continuous calibrated microwave radiometer was also insensitive to system noise fluctuations. The minimum detectable signals were 0.13 and 0.19K respectively under an integration time of 0.6s.
文摘Accurate and reliable river flow information is critical to planning and management for sustainable water resources utilization. Most of engineering activities related to hydrologic designs, flood, drought, reservoirs and their operations are heavily dependent on the river flow information derived from river rating curve. The rating curve for a given river section is normally developed from a set of direct stage-discharge measurements for different periods. This involves considerable labour, risk and resources, and presupposes a complex and extensive measuring survey. Extrapolating the rating curve beyond the measured range, as common in many cases, is fraught with errors and uncertainties, due to the complex hydraulic behaviour of the surface water profile in transition from section, channel, downstream and flood plain controls which are often poorly understood with direct measurements. Hydraulic modeling has recently emerged as one of the more promising methods to efficiently develop accurate rating curves for a river section with simple or complex hydraulic structures and conditions. This paper explores the use of a Hydraulic Engineering Center-River Analysis System (HEC-RAS) model to review and develop river rating curves for three hydrometric stations on two rivers in Kwale, coastal Kenya. The HEC-RAS models were set up based on topographical (cross section and longitudinal) survey data for the reaches and engineering drawings for the hydraulic structures commonly used as section controls for flow measurement. The model was calibrated under unsteady state conditions against measured stage-discharge data which were captured using a Velocity Current Meter (Valeport) and an Acoustic Doppler Current Profiler (ADCP) for both low and high flow. The rating curves were extracted from model results and the uncertainty associated with each rating curve analyzed. The results obtained by the HEC-RAS model were satisfactory and deemed acceptable for predicting discharge across the stage range at each river section.
基金Engineering and Physical Sciences Research Council (EPSRC) is also acknowledged for funding this work under Grant Number EP/N009207/1.
文摘Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks,provide safe and smooth rides,and reduce the maintenance frequency.In this paper,the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in Abaqus.It is then compared to the performance of a ballasted track.First,slab and ballasted track models are developed to replicate the full-scale testing of track sections.Once the models are calibrated with the experimental results,the novel slab model is developed and compared against the calibrated slab track results.The slab and ballasted track models are then extended to create linear dynamic models,considering the track geodynamics,and simulating train passages at various speeds,for which the Ledsgard documented case was used to validate the models.Trains travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil,considering the issues associated with critical speeds.Various train loading methods are discussed,and the most practical approach is retained and described.Moreover,correlations are made between the geotechnical parameters of modern high-speed rail and conventional standards.It is found that considering the same ground condition,the slab track deflections are considerably smaller than those of the ballasted track at high speeds,while they show similar behaviour at low speeds.
基金Project supported by the National Natural Science Foundation of China(Grant No.61775114)
文摘From the perspective of error compensation in the sampling process, a digital calibration algorithm was studied for the processing of spectral data in dual-comb spectroscopy. In this algorithm, dynamic adaptation to phase fluctuations maintained constant measurement results of spectral line positions and intensities. A mode-resolved broadband absorption spectrum was obtained over the full-spectral range of the comb with a Hertz linewidth of radio frequency comb mode.The measured spectrum spanned over 10 THz, which covered the multiplexed absorption regions of mixed gases, such as CO2 and N2 O. The calibrated interferograms were also capable of direct coherent averaging in the time domain. The transmittance obtained deviated from the theoretical calculation by no more than 2% in the whole spectral span.
基金The authors thank the Deanship of Scientific Research at King Khalid University,Kingdom of Saudi Arabia for funding this study through the research groups program under Project Number R.G.P.1/64/42.Ishfaq Ahmad and Ibrahim Mufrah Almanjahie received the grant.
文摘Variance is one of the most vital measures of dispersion widely employed in practical aspects.A commonly used approach for variance estimation is the traditional method of moments that is strongly influenced by the presence of extreme values,and thus its results cannot be relied on.Finding momentum from Koyuncu’s recent work,the present paper focuses first on proposing two classes of variance estimators based on linear moments(L-moments),and then employing them with auxiliary data under double stratified sampling to introduce a new class of calibration variance estimators using important properties of L-moments(L-location,L-cv,L-variance).Three populations are taken into account to assess the efficiency of the new estimators.The first and second populations are concerned with artificial data,and the third populations is concerned with real data.The percentage relative efficiency of the proposed estimators over existing ones is evaluated.In the presence of extreme values,our findings depict the superiority and high efficiency of the proposed classes over traditional classes.Hence,when auxiliary data is available along with extreme values,the proposed classes of estimators may be implemented in an extensive variety of sampling surveys.
基金Under the auspices of National Natural Science Foundation of China(No.42271167)Open Fund of Hubei Key Laboratory of Critical Zone Evolution(No.CZE2022F03)。
文摘Evapotranspiration(ET)is the key to the water cycle process and an important factor for studying near-surface water and heat balance.Accurately estimating ET is significant for hydrology,meteorology,ecology,agriculture,etc..This paper simulates ET in the Madu River Basin of Three Gorges Reservoir Area of China during 2009-2018 based on the Soil and Water Assessment Tool(SWAT)model,which was calibrated and validated using the MODIS(Moderate-resolution Imaging Spectroradiometer)/Terra Net ET 8-Day L4 Global 500 m SIN Grid(MOD16A2)dataset and measured ET.Two calibration strategies(lumped calibration(LC)and spatially distributed calibration(SDC))were used.The basin was divided into 34 sub-basins,and the coefficient of determination(R^(2))and NashSutcliffe efficiency coefficient(NSE)of each sub-basin were greater than 0.6 in both the calibration and validation periods.The R2 and NSE were higher in the validation period than those in the calibration period.Compared with the measured ET,the accuracy of the model on the daily scale is:R^(2)=0.704 and NSE=0.759(SDC results).The model simulation accuracy of LC and SDC for the sub-basin scale was R^(2)=0.857,R^(2)=0.862(monthly)and R^(2)=0.227,R^(2)=0.404(annually),respectively;for the whole basin scale was R^(2)=0.902,R^(2)=0.900(monthly)and R^(2)=0.507 and R^(2)=0.519(annually),respectively.The model performed acceptably,and SDC performed the best,indicating that remote sensing data can be used for SWAT model calibration.During 2009-2018,ET generally increased in the Madu River Basin(SDC results,7.21 mm/yr),with a multiyear average value of 734.37 mm/yr.The annual ET change rate for the sub-basin was relatively low upstream and downstream.The linear correlation analysis between ET and meteorological factors shows that on the monthly scale,precipitation,solar radiation and daily maximum and minimum temperature were significantly correlated with ET;annually,solar radiation and wind speed had a moderate correlation with ET.The correlation between maximum temperature and ET is best on the monthly scale(Pearson correlation coefficient R=0.945),which may means that the increasing ET originating from increasing temperature(global warming).However,the sub-basins near Shennongjia Nature Reserve that are in upstream have a negative ET change rate,which means that ET decreases in these sub-basins,indicating that the’Evaporation Paradox’exists in these sub-basins.This study explored the potential of remote-sensing-based ET data for hydrological model calibration and provides a decision-making reference for water resource management in the Madu River Basin.
基金National Key Research and Development Program of China(2021YFB2802200)National Natural Science Foundation of China(62322217,62005154)+1 种基金Natural Science Foundation of Shanghai Municipality(20ZR1420500)University Grants Committee(ECS27212822,GRF 17208023)。
文摘Holographic near-eye augmented reality(AR)displays featuring tilted inbound/outbound angles on compact optical combiners hold significant potential yet often struggle to deliver satisfying image quality.This is primarily attributed to two reasons:the lack of a robust off-axis-supported phase hologram generation algorithm;and the suboptimal performance of ill-tuned hardware parts such as imperfect holographic optical elements(HOEs).To address these issues,we incorporate a gradient descent-based phase retrieval algorithm with spectrum remapping,allowing for precise hologram generation with wave propagation between nonparallel planes.Further,we apply a camera-calibrated propagation scheme to iteratively optimize holograms,mitigating imperfections arising from the defects in the HOE fabrication process and other hardware parts,thereby significantly lifting the holographic image quality.We build an off-axis holographic near-eye display prototype using off-the-shelf light engine parts and a customized full-color HOE,demonstrating state-of-the-art virtual reality and AR display results.
基金funded by the Catedra Sanitas de Salud y Medio Ambiente of Universidad de Navarrafunded by the Agencia Estatal de Investigatión under the project“Gemelo Digital de Nueva Generatión de Edificios Inteligentes”(DigiTwin)(ref.CPP2021-008909).
文摘European directives advocate for end-users to be aware of their energy consumption.However,individual energy monitoring tools,such as energy meters or cost allocators,are not always affordable or technically feasible to install.Therefore,the development of virtual tools that enable the study of energy consumption in existing buildings is necessary.Virtual sensors,particularly based on white-box models,offer the opportunity to recreate these behaviours.When calibrated with measured data,white-box models,which incorporate detailed building physics,become increasingly valuable for designing energy-efficient buildings.This research explores a novel approach to identifying building’s load period directly from energy data generated by these calibrated models.The volume of data generated by white-box models can be overwhelming for visual analysis,but the hypothesis here is that analysing this data through clustering techniques can reveal patterns related to occupant behaviour and operational schedules.By feeding indoor temperature data into the calibrated model and analysing the resulting energy outputs,the research proposes a method to identify the heating,ventilation and air conditioning(HVAC)system operation schedule,free oscillation periods and non-recurrent events.Validation is achieved by comparing the identified periods with actual measured data.This methodology enables the development of a virtual sensor for cost allocation,which minimises the need for physical sensor deployment while complying with European Union directives.The research not only demonstrates high accuracy but also the potential to outperform measured schedule.This suggests the ability of the method to identify missing sensor data or other factors affecting temperature curves,enabling fault detection and diagnostics(FDD).Consequently,this opens doors for setting optimised operation schedules that balance energy efficiency with occupant comfort.
基金STI2030-Major Projects(2022ZD0212000)Key Research and Development Program of Zhejiang(2024SSYS0014)+4 种基金Beijing Natural Science Foundation(Z240009)National Natural Science Foundation of China(2021MG1BI01,62475129,21927813,T2322001)Strategic Precision Surgery Project at the Institute for Intelligent Healthcare(Tsinghua University)Innovation Fund of the Tsinghua-Foshan Institute of Advanced ManufacturingNational Key Research and Development Program of China(2022ZD0211900,2024YFC3406603)。
文摘The integration of near-infrared genetically encoded reporters(NIR-GERs)with photoacoustic(PA)imaging enables visualizing deep-seated functions of specific cell populations at high resolution,though the imaging depth is primarily constrained by reporters’PA response intensity.Directed evolution can optimize NIR-GERs’performance for PA imaging,yet precise quantifying of PA responses in mutant proteins expressed in E.coli colonies across iterative rounds poses challenges to the imaging speed and quantification capabilities of the screening platforms.Here,we present self-calibrated photoacoustic screening(SCAPAS),an imaging-based platform that can detect samples in parallel within 5 s(equivalent to 50 ms per colony),achieving a considerable quantification accuracy of approximately 2.8%and a quantification precision of about 6.47%.SCAPAS incorporates co-expressed reference proteins in sample preparation and employs a ring transducer array with switchable illumination for rapid,wide-field dual-wavelength PA imaging,enabling precisely calculating the PA response using the self-calibration method.Numerical simulations validated the image optimization strategy,quantification process,and noise robustness.Tests with co-expression samples confirmed SCAPAS’s superior screening speed and quantification capabilities.We believe that SCAPAS will facilitate the development of novel NIR-GERs suitable for PA imaging and has the potential to significantly impact the advancement of PA probes and molecular imaging.
基金supported by the Research Council of Norway through the Centre of Excellence Hylleraas Centre for Quantum Molecular Sciences(Grant 262695)the Young Researcher Talent grants 344993 and 354100+2 种基金We acknowledge the EuroHPC Joint Undertaking for awarding this project access to the EuroHPC supercomputer LUMI,hosted by CSC(Finland)and the LUMI consortium through a EuroHPC Regular Access call(Grants EHPC-REG-2023R02-088,EHPC-REG-2023R03-146)Support was also received from the Centre for Advanced Study in Oslo,Norway,which funded and hosted the SLB Young CAS Fellow research project during the academic year of 23/24 and 24/25Part of the simulations were performed on resources provided by Sigma2—the Norwegian National Infrastructure for High-Performance Computing and Data Storage(grant numbers NN4654K and NS4654K).
文摘Adversarial approaches,which intentionally challenge machine learning models by generating difficult examples,are increasingly being adopted to improve machine learning interatomic potentials(MLIPs).While already providing great practical value,little is known about the actual prediction errors of MLIPs on adversarial structures and whether these errors can be controlled.We propose the Calibrated Adversarial Geometry Optimization(CAGO)algorithm to discover adversarial structures with userassigned errors.Through uncertainty calibration,the estimated uncertainty of MLIPs is unified with real errors.By performing geometry optimization for calibrated uncertainty,we reach adversarial structures with the user-assigned target MLIP prediction error.Integrating with active learning pipelines,we benchmark CAGO,demonstrating stable MLIPs that systematically converge structural,dynamical,and thermodynamical properties for liquid water and water adsorption in a metal-organic framework within only hundreds of training structures,where previously many thousands were typically required.
基金supported by the National Natural Science Foundation of China(No.51576177)the Major Program of the National Natural Science Foundation of China(No.51390491)+1 种基金the National Basic Research Program of China(No.2015CB251501)the Program of Introducing Talents of Discipline to University(No.B08026)
文摘Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry.A novel self-calibrated global rainbow refractometry system based on illumination by two lasers of different wavelengths is proposed.The angular calibration and refractive index measurement of two wavelengths can be completed simultaneously without extra measurement devices.The numerical and experimental results show the feasibility and high precision of the self-calibration method,which enables the rainbow refractometry to be implemented in a more powerful and convenient way.The self-calibrated rainbow system is successfully applied to measure the refractive indices of ethanol-water solutions with volume concentrations of 10% to 60%.
文摘We report a wavelength and power monitoring system based on a scanning MEMS filter as wavelength discriminator and a near threshold-biased Fabry-Perot diode laser as wavelength reference. This system is capable of monitoring 250 channels of DWDM signal at 25 GHz ITU Grid with an error of less than ±8 pm.
基金Supported by Beijing Natural Science Foundation(Grant No.L241012)the National Natural Science Foundation of China(Grant No.62572468).
文摘LiDAR and camera are two of the most common sensors used in the fields of robot perception,autonomous driving,augmented reality,and virtual reality,where these sensors are widely used to perform various tasks such as odometry estimation and 3D reconstruction.Fusing the information from these two sensors can significantly increase the robustness and accuracy of these perception tasks.The extrinsic calibration between cameras and LiDAR is a fundamental prerequisite for multimodal systems.Recently,extensive studies have been conducted on the calibration of extrinsic parameters.Although several calibration methods facilitate sensor fusion,a comprehensive summary for researchers and,especially,non-expert users is lacking.Thus,we present an overview of extrinsic calibration and discuss diverse calibration methods from the perspective of calibration system design.Based on the calibration information sources,this study classifies these methods as target-based or targetless.For each type of calibration method,further classification was performed according to the diverse types of features or constraints used in the calibration process,and their detailed implementations and key characteristics were introduced.Thereafter,calibration-accuracy evaluation methods are presented.Finally,we comprehensively compare the advantages and disadvantages of each calibration method and suggest directions for practical applications and future research.
文摘Eucalyptus(Eucalyptus camaldulensis Dehnh.)is an important exotic species in northern Nigeria commonly used for poles and timber.Sustainable management of this resource would require quantifying its volume.Stem taper equations are one of the main and most efficient methods for estimating stem volume to any merchantable limit of a species.There is currently no taper equation for Eucalyptus species in Nigeria.Therefore,this study developed taper equations for E.camaldulensis in northern Nigeria.Data for this study were obtained from a private plantation in Jalingo Local Government Area,Taraba State,Nigeria.68 trees were felled and sectioned into 1-m bolt across the stem to a merchantable limit of 5 cm,which were used as the fitting dataset.An additional 22 trees were felled and used to validate the taper equations for stem volume estimation.Seven taper equations were initially fitted to the dataset using nonlinear least squares.The best taper equation was then refitted using a nonlinear mixed-effects approach and calibrated using diameters of one to five sections from the butt end.The taper equations were numerically integrated to obtain the stem volume,which was compared with empirical volume equations.The result shows that the Kozak(Can J For Res 27(5):619-629.10.1139/x97-011,1997)equation,which included eight parameters,provided the best fit for predicting section diameters for under and over bark.The mixed-effects taper equation(NLME-TE)explained most stem diameter variations in the fitting dataset(pseudo-R2:0.986-0.987;RMSE:0.547-0.578 cm)without substantial residual trends.The validation showed that the prediction accuracy of the integrated NLME-TE improved as the number of sectional diameter measurements increased,with at least a 35%reduction in volume estimate error.For practical implementation,two calibration sectional diameter measurements taken from the butt end per tree are recommended.This approach would reduce measurement effort and cost while improving model performance.
基金support from the National Natural Science Foundation of China(Grant Nos.U2330206,U2230206,62173068)Sichuan Science and Technology Program(Grants Nos.2024NSFSC1483,2024ZYD0156,2023NSFC1962,DQ202412).
文摘In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorithm under communication constraints to achieve accurate system states of the interested system.An output-based event-triggered scheme is first employed to alleviate transmission burden.Accounting for the limited-communication-induced measurement bias,a novel bias calibration algorithm following the Kalman filtering line is developed to restrain the effect of the measurement bias on system estimation,thereby achieving accurate system state estimates.Subsequently,the Field Programmable Gate Array(FPGA)implementation of the proposed algorithm is also realized with the hope of providing fast bias calibration in practical scenarios.A simulation about a numerical example and a practical example(for gyroscope’s angular velocity bias calibration)on MATLAB is provided to demonstrate the feasibility and effectiveness of the proposed algorithm.
