Accurate kinematic calibration is the very foundation for robots'application in industry demanding high precision such as machining.Considering the complex error characteristic and severe ill-posed identification ...Accurate kinematic calibration is the very foundation for robots'application in industry demanding high precision such as machining.Considering the complex error characteristic and severe ill-posed identification issues of a 5-DoF parallel machining robot,this paper proposes an adaptive and weighted identification method to achieve high-precision kinematic calibration while maintaining reliable stability.First,a kinematic error propagation mechanism model considering the non-ideal constraints and the screw self-rotation is formulated by incorporating the intricate structure of multiple chains and a unique driven screw arrangement of the robot.To address the challenge of accurately identifying such a sophisticated error model,a novel adaptive and weighted identification method based on generalized cross validation(GCV)is proposed.Specifically,this approach innovatively introduces Gauss-Markov estimation into the GCV algorithm and utilizes prior physical information to construct both a weighted identification model and a weighted cross-validation function,thus eliminating the inaccuracy caused by significant differences in dimensional magnitudes of pose errors and achieving accurate identification with flexible numerical stability.Finally,the kinematic calibration experiment is conducted.The comparative experimental results demonstrate that the presented approach is effective and has enhanced accuracy performance over typical least squares methods,with maximum position and orientation errors reduced from 2.279 mm to 0.028 mm and from 0.206°to 0.017°,respectively.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
The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogo...The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogonality error of grating grooves not only improves the positioning accuracy of grating interferometers but also provides essential feedback for optimizing two-dimensional grating fabrication.This study proposes a method for simultaneous calibration of these parameters using orthogonal heterodyne laser interferometry.A two-dimensional grating interferometer is built with the grating to be measured,and a biaxial laser interferometer provides a displacement reference for it.The phase mapping relationship between grating interference and laser interference is established.The interference phase information obtained by any two displacements can simultaneously solve the above three parameters and obtain the grating installation error.The feasibility of the proposed method is verified by using a 1200 gr/mm two-dimensional grating.The standard deviation of the grating groove density in the X and Y directions is 0.012 gr/mm and 0.014 gr/mm,respectively.The standard deviation of the orthogonality error of grating grooves is 0.004°,and the standard deviation of the installation error is 0.002°.Compared with the atomic force microscope method,the consistency of the grating groove density in the X and Y directions is better than 0.03 gr/mm and 0.06 gr/mm,and the orthogonality error of grating grooves is better than 0.008°.The experimental results show that the proposed method can be simply and efficiently applied to the calibration of the grating line parameters of the two-dimensional grating.展开更多
This study investigates the reduction in polarization measurement accuracy caused by varying in-cident angles in a liquid crystal variable retarder(LCVR).The phase delay characteristics of the LCVR were examined,with ...This study investigates the reduction in polarization measurement accuracy caused by varying in-cident angles in a liquid crystal variable retarder(LCVR).The phase delay characteristics of the LCVR were examined,with particular emphasis on the influence of different two-dimensional incident angles on phase delay behavior.Building upon the calibration of phase delay under normal incidence,a phase delay calibra-tion model was developed to account for variations in incident angle and driving voltage.A mathematical re-lationship was established between phase delay and the azimuth angle(α)and pitch angle(β).Experimental validation was conducted under three conditions:α=20°,β=0°;α=0°,β=20°;and an arbitrary angle whereα=5°,β=15°.The results demonstrated that the maximum average deviation between theoretical pre-dictions and experimental measurements did not exceed 0.059 rad.The proposed calibration method proved to be both accurate and practical.This approach offers robust support for LCVR parameter calibration and performance optimization in optical systems,particularly in polarization imaging applications.展开更多
The segmented solar telescope described in this study employs a simultaneous dual-wavelength measurement technique to achieve co-phase alignment.To meet the measurement requirements of a 20μm range,5 nm root mean squ...The segmented solar telescope described in this study employs a simultaneous dual-wavelength measurement technique to achieve co-phase alignment.To meet the measurement requirements of a 20μm range,5 nm root mean square precision,and edge jump rates of<10^(−6),this study focused on calibrating the dual-wavelength measurement system for the segmented-mirror solar telescope.Analysis of the relative error in the measurement system revealed that assembly-induced errors such as defocus,translation,scaling,and rotation markedly degrade measurement accuracy.To address these issues,we propose a defocus error compensation algorithm,based on the light intensity distribution of the point spread function(PSF)and an affine transformation model,to calibrate spatial pose deviations across the two measurement channels.A dual-wavelength measurement system was implemented on a segmented-mirror experimental platform for calibration.Experimental results demonstrated that the mean relative error decreased from−0.6423 to−0.0345 nm after calibration,reflecting improved reliability and stability of the co-phase measurements.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
Background:Investigators from low-,middle-,and high-income countries representing 6 continents contributed to the development of the Global Adolescent and Child Physical Activity Questionnaire(GAC-PAQ).The GAC-PAQ is ...Background:Investigators from low-,middle-,and high-income countries representing 6 continents contributed to the development of the Global Adolescent and Child Physical Activity Questionnaire(GAC-PAQ).The GAC-PAQ is designed to assess physical activity(PA)across all key domains(i.e.,school,chores,work/volunteering,transport,free time,outdoor time).It aimed to address multiple gaps in global PA surveillance(e.g.,omission of important PA domains,insufficient cultural adaptation,underrepresentation of rural areas in questionnaire validation studies).The purpose of this study was to assess the content validity of the GAC-PAQ among PA experts,8-to 17-year-olds,and one of their parents/guardians,and to discuss changes made to the questionnaire based on participants'feedback.Methods:Sixty-two experts in PA measurement and/or surveillance from 24 countries completed an online survey that included both closed-and open-ended questions about the content validity of the GAC-PAQ.The proportion of experts who agreed or strongly agreed with the items was calculated.Child-parent/guardian dyads from 15 countries(n=250;10-40 per country)participated in a structured cognitive interview to assess the clarity of the questions and response options,and they were encouraged to provide suggestions to improve clarity and facilitate completion of the questionnaire.Participating countries are:Aotearoa New Zealand,Brazil,Canada,China,Colombia,Czech Republic,India,Malawi,Mexico,Nepal,Nigeria,Spain,Sweden,Thailand,and the United Arab Emirates.Interviews were conducted in 13 different languages and structured by PA domain.Generic images were included to help participants in answering questions about PA intensity.Results:Expert agreement with the items for each domain exceeded 75%,and their qualitative feedback was used to revise the questionnaire before cognitive interviews.In general,participants found the questionnaire to be comprehensive.Adolescents(12-17 years)found it easier than children(8-11 years)to answer the questions.Several children struggled to answer questions about the duration and intensity of activities and/or concepts related to travel modes,active trips,and organized activities.Many parents/guardians were unsure about the frequency,duration,and intensity of their children's or adolescents'PA at school and/or recommended using more culturally relevant and appropriate images.Some participants misunderstood the concept of activities that“make you stronger”(intended to assess resistance activities)and/or struggled to differentiate between work,volunteering,and chores.Conclusion:Participants'feedback was used to develop a revised,simplified,and culturally adapted GAC-PAQ,which will be pilot-tested in all15 countries in an App that will include country-specific images and narration in local languages.Further research is needed to assess the reliability and validity of the revised GAC-PAQ.展开更多
Background:The World Health Organization Disability Assessment Schedule 2.0(WHODAS 2.0)is a popular tool for eval-uating functioning and disability in a range of population demographics and medical situations.However,...Background:The World Health Organization Disability Assessment Schedule 2.0(WHODAS 2.0)is a popular tool for eval-uating functioning and disability in a range of population demographics and medical situations.However,very little is known about the WHODAS 2.0's validity and reliability,particularly when dealing with potentially life-threatening maternal condi-tions(PLTCs).The aim of this study was to evaluate the validity of the WHODAS 2.0 Tigrigna version.Methods:This cross-sectional study was conducted in Tigray,northern Ethiopia,from December 15 to 20,2023.Following translation and back translation,women who had experienced PLTCs during a recent pregnancy,childbirth,or postpartum period were administered the 36-item WHODAS 2.0 in Tigrigna version 6 months after the childbirth.In total,121 women with a history of PLTCs participated.Cronbach′sαwas used to evaluate internal consistency in all six WHODAS 2.0 domains,while Spearman′s correlation coefficient was used to evaluate convergent validity.With confirmatory factor analysis,construct validity was also examined.Results:All domain scores of the Tigrigna version of the WHODAS 2.0 indicated excellent internal consistency(α=0.917-0.978 for 36 items andα=0.874-0.940 for 12 items),while the Cronbach′sαcoefficients for the summary score were 0.981 and 0.952 for 36 and 12 items,respectively.The convergent validity between the 36-item and 12-item WHODAS 2.0 showed a strong correlation between similar constructs(r=0.909-0.981).Conclusion:Despite the small sample limitation,the WHODAS 2.0 tool adapted to the Tigrigna version indicated an acceptable reliability and validity and therefore could be applied to women with a history of PLTCs at 6 months postpartum.展开更多
With the widespread adoption of digital equipment in intelligent substations,testing digital signals in power systems has become an important role for relay protection test equipment.Testing and calibrating digital si...With the widespread adoption of digital equipment in intelligent substations,testing digital signals in power systems has become an important role for relay protection test equipment.Testing and calibrating digital signals require high accuracy.However,existing methods have low precision,cannot be calibrated at full range for all indexes,and have complex configuration,making them unsuitable for routine calibration work.To solve the above problems,a novel calibration method is designed and implemented using field programmable gate array(FPGA)to achieve accurate input and output time control.Accurate calibration relies on multiple forms of traceability including theoretical value traceability based on waveform comparison,time scale value traceability based on accurate time stamps,and algorithm traceability based on typical algorithms.Compared with other existing methods,the proposed approach reduces the mean absolute error of action time and time measurement by 92.88%,effectively addressing a key industry challenge and offering a valuable reference for further research,application,and standardization.展开更多
We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-...We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-energy calibration source with a half-life of 35.01 days,making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments.Radioactive isotope^(37)Ar was produced by irradiating ^(36)Ar with thermal neutrons.It was subsequently measured in a gaseous xenon time projection chamber(GXe TPC)to validate its radioactivity.Our results demonstrate that^(37)Ar is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.展开更多
It remains difficult to automate the creation and validation of Unified Modeling Language(UML)dia-grams due to unstructured requirements,limited automated pipelines,and the lack of reliable evaluation methods.This stu...It remains difficult to automate the creation and validation of Unified Modeling Language(UML)dia-grams due to unstructured requirements,limited automated pipelines,and the lack of reliable evaluation methods.This study introduces a cohesive architecture that amalgamates requirement development,UML synthesis,and multimodal validation.First,LLaMA-3.2-1B-Instruct was utilized to generate user-focused requirements.Then,DeepSeek-R1-Distill-Qwen-32B applies its reasoning skills to transform these requirements into PlantUML code.Using this dual-LLM pipeline,we constructed a synthetic dataset of 11,997 UML diagrams spanning six major diagram families.Rendering analysis showed that 89.5%of the generated diagrams compile correctly,while invalid cases were detected automatically.To assess quality,we employed a multimodal scoring method that combines Qwen2.5-VL-3B,LLaMA-3.2-11B-Vision-Instruct and Aya-Vision-8B,with weights based on MMMU performance.A study with 94 experts revealed strong alignment between automatic and manual evaluations,yielding a Pearson correlation of r=0.82 and a Fleiss’Kappa of 0.78.This indicates a high degree of concordance between automated metrics and human judgment.Overall,the results demonstrated that our scoring system is effective and that the proposed generation pipeline produces UML diagrams that are both syntactically correct and semantically coherent.More broadly,the system provides a scalable and reproducible foundation for future work in AI-driven software modeling and multimodal verification.展开更多
Background:Antipsychotic-induced movement disorders(AIMDs)are prevalent side effects of antipsychotics,particularly during the acute phase of treatment.This study aimed to elucidate the genetic mechanisms underlying A...Background:Antipsychotic-induced movement disorders(AIMDs)are prevalent side effects of antipsychotics,particularly during the acute phase of treatment.This study aimed to elucidate the genetic mechanisms underlying AIMDs using a genome-wide association study(GWAS).Methods:GWASs on AIMDs were conducted in three independent cohorts:a discovery cohort of 3067 patients(2016 subjects were reserved after quality control),a validation cohort of 277 patients,and a multi-ancestry validation cohort of 766 patients.Subsequent post-GWAS analyses included gene-based analyses,transcriptome-wide association studies(TWASs),and polygenic risk score(PRS)profiling.Results:Our study identified two loci located in RAB44 gene(rs116249243,P=5.98×10^(-9);rs117097482,P=1.17×10^(-8))associated with extrapyramidal symptoms(EPSs),1 locus(rs6826172,P=5.56×10^(-9))related to akathisia,and 76 loci linked to involuntary movements(11 genes were mapped).Risk loci located in CNTNAP2,LUZP2,TMEM167A,and RAB44 genes were successfully replicated in the validation cohort,whereas the locus located in RAB44 was also replicated in the multi-ancestry cohort.Gene-based analyses indicated that XRCC4 and PAIP2B reached significance at the genome-wide level in involuntary movements.Tissue expression analysis revealed that involuntary movement-related genes are predominantly expressed in the substantia nigra.Additionally,the TWAS suggested a causal relationship between XRCC4 and involuntary movement.The PRSs derived from the discovery cohort significantly predicted AIMDs in the validation cohort,with area under the receiver operating characteristic curve(AUC)values from 0.60 to 0.80.Conclusions:Our findings highlight the role of substantia nigra related gene polymorphisms in AIMDs.This study provides novel insights into the pathogenesis of AIMDs and supports the potential for personalized treatment approaches for schizophrenia.展开更多
Considering the drastic variations in the surface elevation of the piedmont region in the Bai Cheng West Area,there is no reference point within the Reference Ground Line(RG line)of the starting point of the synthetic...Considering the drastic variations in the surface elevation of the piedmont region in the Bai Cheng West Area,there is no reference point within the Reference Ground Line(RG line)of the starting point of the synthetic seismic records in the process of calibration of the horizon.Through the analysis of the process and properties of the production of the RG line,in the processing of seismic data,it is indicated that the position of the synthetic data of seismic records is not located at the beginning of the RG line.Rather,it must be at the time point of the seismic profile at the elevation of a datum position of the static value of less than the datum plane.Both the RG line and the elevation static correction value line can easily be seen by computerizing the calculated value of the elevation static correction of the datum plane relating to the seismic section and plotting it on the seismic section.To achieve a good calibration with the synthetic seismogram,it is possible to set the starting point of the synthetic seismogram on the elevation static correction value line that is situated at the place of the Common Mid-Point(CMP).In the current paper,a systematic overview of methods and safety procedures for establishing the seismic interpretation work area and horizon calibration in seismic interpretation has been reviewed,which will form an effective guide towards seismic interpretation under the complicated surface conditions in the Bai Cheng west region.展开更多
Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properti...Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properties of materials under extreme high-pressure and hightemperature conditions.A prerequisite for achieving reproducible property measurements is the determination and control of pressure within experimental setups.However,the lack of precise pressure calibration in LVPs hinders the broader application of such devices in ultrahigh-pressure studies.This study employs a suite of standard phase transition-based pressure markers—comprising metallic conductors,semiconductors,and minerals—through both in situ and ex situ identification approaches,to establish pressure calibration curves ranging from 0.4 to>30 GPa for various types of LVP installed at the Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing,including piston–cylinder,cubic,and multi-anvil presses.The results provide a unified and traceable pressure reference for highpressure experiments conducted at HPSTAR,while also offering technical guidance and calibration standards for other researchers utilizing similar LVP systems,thereby enabling more consistent comparison between different laboratories.This work facilitates the advancement of LVP research toward broader applications in higher-pressure regimes.展开更多
The application of the Soil and Water Assessment Tool (SWAT) to the Olifants Basin in South Africa was the focus of our study with emphasis on calibration, validation and uncertainty analysis. The Basin was discretize...The application of the Soil and Water Assessment Tool (SWAT) to the Olifants Basin in South Africa was the focus of our study with emphasis on calibration, validation and uncertainty analysis. The Basin was discretized into 23 sub-basins and 226 Hydrologic Response Units (HRUs) using 3 arc second (90 m × 90 m) pixel resolution SRTM DEM with stream gauge B7H015 as the Basin outlet. Observed stream flow data at B7H015 were used for model calibration (1988-2001) and validation (2002-2013) using the split sample approach. Relative global sensitivity analysis using SUFI-2 algorithm was used to determine sensitive parameters to stream flow for calibration of the model. Performance efficiency of the Olifants SWAT model was assessed using Nash-Sutcliffe (NSE), coefficient of determination (R<sup>2</sup>), Percent Bias (PBIAS) and Root Mean Square Error-Observation Standard deviation Ratio (RSR). Sensitivity analysis revealed in decreasing order of significance, runoff curve number (CN2), alpha bank factor (ALPHA_BNK), soil evaporation compensation factor (ESCO), soil available water capacity (SOIL_AWC, mm H<sub>2</sub>O/mm soil), groundwater delay (GW_ DELAY, days) and groundwater “revap” coefficient (GW_REVAP) to be the most sensitive parameters to stream flow. Analysis of the model during the calibration period gave the following statistics;NSE = 0.88;R<sup>2</sup> = 0.89;PBIAS = -11.49%;RSR = 0.34. On the other hand, statistics during the validation period were NSE = 0.67;R<sup>2 </sup>= 0.79;PBIAS = -20.69%;RSR = 0.57. The observed statistics indicate the applicability of the SWAT model in simulating the hydrology of the Olifants Basin and therefore can be used as a Decision Support Tool (DST) by water managers and other relevant decisions making bodies to influence policy directions on the management of watershed processes especially water resources.展开更多
Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using a...Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using aggregated or limited data. If their calibration is regularly mentioned in the literature, their validation is barely discussed. In this paper, several modal choice model specifications that make only use of explanatory variables available at the network level are described and applied to a large scale case. A validation exercise is performed at three levels of aggregation. The paper is designed from a strategic transport planning perspective, and does not present new modal choice formulations or assignment procedures. Its main added value is the focus on calibration and validation considerations. Despite the limited explanatory information used, the global performance of the best models can be considered as satisfactory. However, the quality of the models varies from mode to mode, the use of railway transport being the most difficult to predict without more specific input.展开更多
Background: In the context of a nuclear reactor accident, thyroid is the main target organ of radioactive iodines. To avoid as much as possible thyroid disorders or even cancer development, it is recommended to admini...Background: In the context of a nuclear reactor accident, thyroid is the main target organ of radioactive iodines. To avoid as much as possible thyroid disorders or even cancer development, it is recommended to administer a single dose of potassium iodide to people at risk of exposure. Nevertheless, the Fukushima Dai-ichi disaster has pointed out many questions about the conditions of stable iodine prophylaxis implementation highlighting the need for reflection further revision of the actual “iodine doctrine”. Therefore, providing useful data is required notably through the implementation of animal experiments to strengthen current knowledge and to edit new recommendations. Methods: Urinary iodine constitutes a very good indicator to investigate the function of thyroid, its interpretation demands reliable analyses. Prior to perform animal experiments, two calibration methods were designed by our lab and compared together (standard addition and external calibration) to assess the urinary concentration of stable iodine in urine by ICP-MS. They were validated based on several key parameters especially linearity, accuracy and limits of detection (LOD) and quantification (LOQ). Results: The results were nicely satisfying. Indeed, both calibration methods have indicated very good coefficients of correlations, accuracies with low expanded relative uncertainties were obtained. The estimated LOD in the sample for standard addition method and external calibration were fully acceptable, 0.39 μg·L-1 and 0.35 μg·L-1, respectively. All performance criteria have been thus fulfilled successfully. The established methods were proven to be accurate, robust and sensitive. Once validated, both calibration methods were applied to rat urine samples and the results of z-score and Wilcoxon W test concluded that there were no statistically significant differences between both methods.展开更多
Maize is an emerging important crop in Bangladesh because of its high yield potential and economic profitability compared to rice and wheat crops. There is a need to understand the growth and yield behavior of this cr...Maize is an emerging important crop in Bangladesh because of its high yield potential and economic profitability compared to rice and wheat crops. There is a need to understand the growth and yield behavior of this crop in varying production environments of Bangladesh. Crop model such as Decision Support System For Agro-technology Transfer (DSSAT) version 4.6 (DSSAT hereafter) can be utilized cost effectively to study the performances of maize under different production environments. It needs to calibrate and validate DSSAT model for commonly cultivated maize cultivars in Bangladesh and subsequently take the model to various applications, including inputs and agronomic management options and climate change that impacts analyses. So, the present study was undertaken to firstly calibrate DSSAT model for popular four hybrid maize cultivars (BARI Hybrid Maize-7, BARI Hybrid Maize-9, Pioneer 30B07 and NK-40). Subsequently, it proceeded with the validation with independent field data sets for evaluating their growth performances. The genetic coefficients for these cultivars were evaluated by using Genotype coefficient calculator (GENCALC) and Generalized likelihood uncertainty estimation (GLUE) module of DSSAT on the basis of first season experiment. The performance of the model was satisfactory and within the significant limits. After calibration, the model was tested for its performance through validation procedure by using second season data. The model performed satisfactorily through phenology, biomass, leaf area index (LAI) and grain yield. Phenology, as estimated through days to flower initiation and maturity, was in good agreement, although simulated results were slightly over predicted compared to observed values but within the statistical significance limit...when compared with observed values at specific growth stages of the crop. The final yield values (10.12 to 10.59 t·ha-1) were in close agreement with the observed values (10.16 to 10.94 t·ha-1), as the percentage error was within tolerable limit (0.39% to 6.81%). The model has been successfully calibrated and validated for Gazipur environment and now can be used for climate change impact studies for similar environments in Bangladesh.展开更多
Soybean and sunflower are summer annuals that can be grown as an alternative to corn and may be particularly useful in organic production systems for forage in addition to their traditional use as protein and/or oil y...Soybean and sunflower are summer annuals that can be grown as an alternative to corn and may be particularly useful in organic production systems for forage in addition to their traditional use as protein and/or oil yielding crops. Rapid and low cost methods of analyzing plant forage quality would be helpful for nutrition management of livestock. We developed and validated calibration models using Near-infrared Reflectance Spectroscopic (NIRS) analysis for 27 different forage quality parameters of organically grown sunflower and soybean leaves or reproductive parts. Crops were managed under conventional tillage or no-till with a cover crop of wheat before soybean and rye-crimson clover before sunflower. From a population of 120 samples from both crops, covering multiple sampling dates within the treatments, calibration models were developed utilizing spectral information covering both visible and NIR region of 61 - 85 randomly chosen samples using modified partial least-squares (MPLS) regression with internal cross validation. Within MPLS protocol, we compared nine different math treatments on the quality of the calibration models. The math treatment “2,4,4,1” yielded the best quality models for all but starch and simple sugars (r2 = 0.699 - 0.999;where the 1st digit is the number of the derivative with 0 for raw spectra, 1 for first derivative, and 2 for second derivative, the 2nd digit is the gap over which the derivative is calculated, the 3rd digit is the number of data points in a running average or smoothing, and the 4th digit is the second smoothing). Prediction of an independent validation set of 28-35 samples with these models yielded excellent agreement between the NIRS predicted values and the reference values except for starch (r2 = 0.8260 - 0.9990). The results showed that the same model was able to adequately quantify a particular forage quality of both crops managed under different tillage treatments and at different stages of growth. Thus, these models can be reliably applied in the routine analysis of soybean and sunflower forage quality for the purposes of livestock nutrient management decisions.展开更多
The hydrologic simulation of a catchment area, described as the transformation of rainfall into runoff, generally uses hydrologic model. This work opts for the global conceptual hydrologic model GR2M, a monthly time s...The hydrologic simulation of a catchment area, described as the transformation of rainfall into runoff, generally uses hydrologic model. This work opts for the global conceptual hydrologic model GR2M, a monthly time step model, to study the Kouilou-Niari basin, the second most important ones of the Republic of Congo. This includes two parameters to model the hydrologic behavior of a catchment area. The choice of the conceptual model GR2M is justified by the reduced number of parameters and the monthly time scale. The objective of this study is to determine the characteristic parameters of the GR2M model, by a calibrating and a validating procedure. The use of these parameters enables to follow the evolution of the water resources from the climatic variables. It has been first carried out a characterization of some physical, geological and climatic factors governing the flow, by dealing with the main climatic variables which constitute the inputs of the hydrologic model. Then, a hydrologic rainfall-runoff modeling allows to calibrate and validate the model at monthly time scale. Taking into account the number of parameters involved in hydrologic processes and the complexity of the cathment area, this model gives acceptable results throughout the Kouilou-Niari basin. The values of the Nash-Sutcliffe criterion and those of the correlation coefficient obtained are greater than 80% in validation, which explains the performance and robustness of the GR2M model on this basin.展开更多
基金Supported by National Key R&D Program of China(Grant No.2022YFB3404101)National Natural Science Foundation of China(Grant Nos.52375018,92148301)。
文摘Accurate kinematic calibration is the very foundation for robots'application in industry demanding high precision such as machining.Considering the complex error characteristic and severe ill-posed identification issues of a 5-DoF parallel machining robot,this paper proposes an adaptive and weighted identification method to achieve high-precision kinematic calibration while maintaining reliable stability.First,a kinematic error propagation mechanism model considering the non-ideal constraints and the screw self-rotation is formulated by incorporating the intricate structure of multiple chains and a unique driven screw arrangement of the robot.To address the challenge of accurately identifying such a sophisticated error model,a novel adaptive and weighted identification method based on generalized cross validation(GCV)is proposed.Specifically,this approach innovatively introduces Gauss-Markov estimation into the GCV algorithm and utilizes prior physical information to construct both a weighted identification model and a weighted cross-validation function,thus eliminating the inaccuracy caused by significant differences in dimensional magnitudes of pose errors and achieving accurate identification with flexible numerical stability.Finally,the kinematic calibration experiment is conducted.The comparative experimental results demonstrate that the presented approach is effective and has enhanced accuracy performance over typical least squares methods,with maximum position and orientation errors reduced from 2.279 mm to 0.028 mm and from 0.206°to 0.017°,respectively.
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The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogonality error of grating grooves not only improves the positioning accuracy of grating interferometers but also provides essential feedback for optimizing two-dimensional grating fabrication.This study proposes a method for simultaneous calibration of these parameters using orthogonal heterodyne laser interferometry.A two-dimensional grating interferometer is built with the grating to be measured,and a biaxial laser interferometer provides a displacement reference for it.The phase mapping relationship between grating interference and laser interference is established.The interference phase information obtained by any two displacements can simultaneously solve the above three parameters and obtain the grating installation error.The feasibility of the proposed method is verified by using a 1200 gr/mm two-dimensional grating.The standard deviation of the grating groove density in the X and Y directions is 0.012 gr/mm and 0.014 gr/mm,respectively.The standard deviation of the orthogonality error of grating grooves is 0.004°,and the standard deviation of the installation error is 0.002°.Compared with the atomic force microscope method,the consistency of the grating groove density in the X and Y directions is better than 0.03 gr/mm and 0.06 gr/mm,and the orthogonality error of grating grooves is better than 0.008°.The experimental results show that the proposed method can be simply and efficiently applied to the calibration of the grating line parameters of the two-dimensional grating.
文摘This study investigates the reduction in polarization measurement accuracy caused by varying in-cident angles in a liquid crystal variable retarder(LCVR).The phase delay characteristics of the LCVR were examined,with particular emphasis on the influence of different two-dimensional incident angles on phase delay behavior.Building upon the calibration of phase delay under normal incidence,a phase delay calibra-tion model was developed to account for variations in incident angle and driving voltage.A mathematical re-lationship was established between phase delay and the azimuth angle(α)and pitch angle(β).Experimental validation was conducted under three conditions:α=20°,β=0°;α=0°,β=20°;and an arbitrary angle whereα=5°,β=15°.The results demonstrated that the maximum average deviation between theoretical pre-dictions and experimental measurements did not exceed 0.059 rad.The proposed calibration method proved to be both accurate and practical.This approach offers robust support for LCVR parameter calibration and performance optimization in optical systems,particularly in polarization imaging applications.
基金supported by the Yunnan Revitalization Talent Support Program(202305AS350029 and 202305AT350005)Yunnan Revitalization Talent Support Program-Science&Technology Champion Project(202105AB160001)+1 种基金Yunnan Key Laboratory of Solar Physics and Space Science(202205AG070009)Yunnan Provincial Science and Technology Department(202401AU070062).
文摘The segmented solar telescope described in this study employs a simultaneous dual-wavelength measurement technique to achieve co-phase alignment.To meet the measurement requirements of a 20μm range,5 nm root mean square precision,and edge jump rates of<10^(−6),this study focused on calibrating the dual-wavelength measurement system for the segmented-mirror solar telescope.Analysis of the relative error in the measurement system revealed that assembly-induced errors such as defocus,translation,scaling,and rotation markedly degrade measurement accuracy.To address these issues,we propose a defocus error compensation algorithm,based on the light intensity distribution of the point spread function(PSF)and an affine transformation model,to calibrate spatial pose deviations across the two measurement channels.A dual-wavelength measurement system was implemented on a segmented-mirror experimental platform for calibration.Experimental results demonstrated that the mean relative error decreased from−0.6423 to−0.0345 nm after calibration,reflecting improved reliability and stability of the co-phase measurements.
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.
基金supported by a Project Grant(Grant No.PJT183705)an Early Career Investigator Prize(Grant No.ECP 184184)from the Canadian Institutes of Health Research+7 种基金a Prentice Institute Research Affiliate Fund Grant from the Prentice Institute for Global Population and Economy(Grant No.G00004116)a Te Herenga Waka Victoria University of Wellington Division of Science Health Engineering Architecture and Design Innovation Faculty Strategic Research Grant(Grant No.FSRG-SHEADI-10724)The Thailand Physical Activity Knowledge Development Centre(TPAK)/Thai Health Promotion Foundation provided funding for the cognitive interviews and pilot study in Thailand(Grant No.66-P1-0473)The University Pablo de Olavide provided a scholarship for 2 undergraduate students working on the project(codes PPI2207 and PPI2308)In the Czech Republicthe study was supported by Palacky University IGA(Grant No.IGA_FTK_2023_017)supported by the Division of Intramural Research at the National Institute on Minority Health and Health Disparities of the National Institutes of Healthsupported by the Key Project of the National Philosophy and Social Science Foundation of China(23&ZD197)。
文摘Background:Investigators from low-,middle-,and high-income countries representing 6 continents contributed to the development of the Global Adolescent and Child Physical Activity Questionnaire(GAC-PAQ).The GAC-PAQ is designed to assess physical activity(PA)across all key domains(i.e.,school,chores,work/volunteering,transport,free time,outdoor time).It aimed to address multiple gaps in global PA surveillance(e.g.,omission of important PA domains,insufficient cultural adaptation,underrepresentation of rural areas in questionnaire validation studies).The purpose of this study was to assess the content validity of the GAC-PAQ among PA experts,8-to 17-year-olds,and one of their parents/guardians,and to discuss changes made to the questionnaire based on participants'feedback.Methods:Sixty-two experts in PA measurement and/or surveillance from 24 countries completed an online survey that included both closed-and open-ended questions about the content validity of the GAC-PAQ.The proportion of experts who agreed or strongly agreed with the items was calculated.Child-parent/guardian dyads from 15 countries(n=250;10-40 per country)participated in a structured cognitive interview to assess the clarity of the questions and response options,and they were encouraged to provide suggestions to improve clarity and facilitate completion of the questionnaire.Participating countries are:Aotearoa New Zealand,Brazil,Canada,China,Colombia,Czech Republic,India,Malawi,Mexico,Nepal,Nigeria,Spain,Sweden,Thailand,and the United Arab Emirates.Interviews were conducted in 13 different languages and structured by PA domain.Generic images were included to help participants in answering questions about PA intensity.Results:Expert agreement with the items for each domain exceeded 75%,and their qualitative feedback was used to revise the questionnaire before cognitive interviews.In general,participants found the questionnaire to be comprehensive.Adolescents(12-17 years)found it easier than children(8-11 years)to answer the questions.Several children struggled to answer questions about the duration and intensity of activities and/or concepts related to travel modes,active trips,and organized activities.Many parents/guardians were unsure about the frequency,duration,and intensity of their children's or adolescents'PA at school and/or recommended using more culturally relevant and appropriate images.Some participants misunderstood the concept of activities that“make you stronger”(intended to assess resistance activities)and/or struggled to differentiate between work,volunteering,and chores.Conclusion:Participants'feedback was used to develop a revised,simplified,and culturally adapted GAC-PAQ,which will be pilot-tested in all15 countries in an App that will include country-specific images and narration in local languages.Further research is needed to assess the reliability and validity of the revised GAC-PAQ.
文摘Background:The World Health Organization Disability Assessment Schedule 2.0(WHODAS 2.0)is a popular tool for eval-uating functioning and disability in a range of population demographics and medical situations.However,very little is known about the WHODAS 2.0's validity and reliability,particularly when dealing with potentially life-threatening maternal condi-tions(PLTCs).The aim of this study was to evaluate the validity of the WHODAS 2.0 Tigrigna version.Methods:This cross-sectional study was conducted in Tigray,northern Ethiopia,from December 15 to 20,2023.Following translation and back translation,women who had experienced PLTCs during a recent pregnancy,childbirth,or postpartum period were administered the 36-item WHODAS 2.0 in Tigrigna version 6 months after the childbirth.In total,121 women with a history of PLTCs participated.Cronbach′sαwas used to evaluate internal consistency in all six WHODAS 2.0 domains,while Spearman′s correlation coefficient was used to evaluate convergent validity.With confirmatory factor analysis,construct validity was also examined.Results:All domain scores of the Tigrigna version of the WHODAS 2.0 indicated excellent internal consistency(α=0.917-0.978 for 36 items andα=0.874-0.940 for 12 items),while the Cronbach′sαcoefficients for the summary score were 0.981 and 0.952 for 36 and 12 items,respectively.The convergent validity between the 36-item and 12-item WHODAS 2.0 showed a strong correlation between similar constructs(r=0.909-0.981).Conclusion:Despite the small sample limitation,the WHODAS 2.0 tool adapted to the Tigrigna version indicated an acceptable reliability and validity and therefore could be applied to women with a history of PLTCs at 6 months postpartum.
基金supported by the Key Technologies R&D Program of Henan Province(No.242102211065)Postgraduate Education Reform and Quality Im-provement Project of Henan Province(No.YJS2025GZZ36).
文摘With the widespread adoption of digital equipment in intelligent substations,testing digital signals in power systems has become an important role for relay protection test equipment.Testing and calibrating digital signals require high accuracy.However,existing methods have low precision,cannot be calibrated at full range for all indexes,and have complex configuration,making them unsuitable for routine calibration work.To solve the above problems,a novel calibration method is designed and implemented using field programmable gate array(FPGA)to achieve accurate input and output time control.Accurate calibration relies on multiple forms of traceability including theoretical value traceability based on waveform comparison,time scale value traceability based on accurate time stamps,and algorithm traceability based on typical algorithms.Compared with other existing methods,the proposed approach reduces the mean absolute error of action time and time measurement by 92.88%,effectively addressing a key industry challenge and offering a valuable reference for further research,application,and standardization.
基金supported by National Key R&D grant from the Ministry of Science and Technology of China(Nos.2021YFA1601600,2023YFA1606200)National Science Foundation of China(Nos.12090062,12105008)the Major State Basic Research Development Program of China.
文摘We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-energy calibration source with a half-life of 35.01 days,making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments.Radioactive isotope^(37)Ar was produced by irradiating ^(36)Ar with thermal neutrons.It was subsequently measured in a gaseous xenon time projection chamber(GXe TPC)to validate its radioactivity.Our results demonstrate that^(37)Ar is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.
基金supported by the DH2025-TN07-07 project conducted at the Thai Nguyen University of Information and Communication Technology,Thai Nguyen,Vietnam,with additional support from the AI in Software Engineering Lab.
文摘It remains difficult to automate the creation and validation of Unified Modeling Language(UML)dia-grams due to unstructured requirements,limited automated pipelines,and the lack of reliable evaluation methods.This study introduces a cohesive architecture that amalgamates requirement development,UML synthesis,and multimodal validation.First,LLaMA-3.2-1B-Instruct was utilized to generate user-focused requirements.Then,DeepSeek-R1-Distill-Qwen-32B applies its reasoning skills to transform these requirements into PlantUML code.Using this dual-LLM pipeline,we constructed a synthetic dataset of 11,997 UML diagrams spanning six major diagram families.Rendering analysis showed that 89.5%of the generated diagrams compile correctly,while invalid cases were detected automatically.To assess quality,we employed a multimodal scoring method that combines Qwen2.5-VL-3B,LLaMA-3.2-11B-Vision-Instruct and Aya-Vision-8B,with weights based on MMMU performance.A study with 94 experts revealed strong alignment between automatic and manual evaluations,yielding a Pearson correlation of r=0.82 and a Fleiss’Kappa of 0.78.This indicates a high degree of concordance between automated metrics and human judgment.Overall,the results demonstrated that our scoring system is effective and that the proposed generation pipeline produces UML diagrams that are both syntactically correct and semantically coherent.More broadly,the system provides a scalable and reproducible foundation for future work in AI-driven software modeling and multimodal verification.
基金supported by the National Natural Science Foundation of China(82330042,82441005 and 82301687)the National Key R&D Program of China(2023YFE0119400)+9 种基金the Capital’s Funds for Health Improvement and Research(2024-1-4111)the STI2030-Major Projects-2021ZD0200702Fundamental Research Funds for the Central Universities(Peking University Medicine Fund for world’s leading discipline or discipline cluster development,BMU2022DJXK007)the Beijing Municipal Health Commission Research Ward Programme(3rd batch)Beijing Nova Program(20230484425)the Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(Z221100003522010)the China Postdoctoral Science Foundation(2024M760141 and 2022M720302)the National Postdoctoral Program for Innovative Talents(BX20240029)the Beijing Natural Science Foundation(7254462)the Peking University Medicine Sailing Program for Young Scholars’Scientific&Technological Innovation,the Fundamental Research Funds for the Central Universities(BMU2025YFJHPY044 and BMU2025YFJHPY046).
文摘Background:Antipsychotic-induced movement disorders(AIMDs)are prevalent side effects of antipsychotics,particularly during the acute phase of treatment.This study aimed to elucidate the genetic mechanisms underlying AIMDs using a genome-wide association study(GWAS).Methods:GWASs on AIMDs were conducted in three independent cohorts:a discovery cohort of 3067 patients(2016 subjects were reserved after quality control),a validation cohort of 277 patients,and a multi-ancestry validation cohort of 766 patients.Subsequent post-GWAS analyses included gene-based analyses,transcriptome-wide association studies(TWASs),and polygenic risk score(PRS)profiling.Results:Our study identified two loci located in RAB44 gene(rs116249243,P=5.98×10^(-9);rs117097482,P=1.17×10^(-8))associated with extrapyramidal symptoms(EPSs),1 locus(rs6826172,P=5.56×10^(-9))related to akathisia,and 76 loci linked to involuntary movements(11 genes were mapped).Risk loci located in CNTNAP2,LUZP2,TMEM167A,and RAB44 genes were successfully replicated in the validation cohort,whereas the locus located in RAB44 was also replicated in the multi-ancestry cohort.Gene-based analyses indicated that XRCC4 and PAIP2B reached significance at the genome-wide level in involuntary movements.Tissue expression analysis revealed that involuntary movement-related genes are predominantly expressed in the substantia nigra.Additionally,the TWAS suggested a causal relationship between XRCC4 and involuntary movement.The PRSs derived from the discovery cohort significantly predicted AIMDs in the validation cohort,with area under the receiver operating characteristic curve(AUC)values from 0.60 to 0.80.Conclusions:Our findings highlight the role of substantia nigra related gene polymorphisms in AIMDs.This study provides novel insights into the pathogenesis of AIMDs and supports the potential for personalized treatment approaches for schizophrenia.
文摘Considering the drastic variations in the surface elevation of the piedmont region in the Bai Cheng West Area,there is no reference point within the Reference Ground Line(RG line)of the starting point of the synthetic seismic records in the process of calibration of the horizon.Through the analysis of the process and properties of the production of the RG line,in the processing of seismic data,it is indicated that the position of the synthetic data of seismic records is not located at the beginning of the RG line.Rather,it must be at the time point of the seismic profile at the elevation of a datum position of the static value of less than the datum plane.Both the RG line and the elevation static correction value line can easily be seen by computerizing the calculated value of the elevation static correction of the datum plane relating to the seismic section and plotting it on the seismic section.To achieve a good calibration with the synthetic seismogram,it is possible to set the starting point of the synthetic seismogram on the elevation static correction value line that is situated at the place of the Common Mid-Point(CMP).In the current paper,a systematic overview of methods and safety procedures for establishing the seismic interpretation work area and horizon calibration in seismic interpretation has been reviewed,which will form an effective guide towards seismic interpretation under the complicated surface conditions in the Bai Cheng west region.
基金supported by the National Science Foundation of China(Grant Nos.U1530402 and U1930401).
文摘Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properties of materials under extreme high-pressure and hightemperature conditions.A prerequisite for achieving reproducible property measurements is the determination and control of pressure within experimental setups.However,the lack of precise pressure calibration in LVPs hinders the broader application of such devices in ultrahigh-pressure studies.This study employs a suite of standard phase transition-based pressure markers—comprising metallic conductors,semiconductors,and minerals—through both in situ and ex situ identification approaches,to establish pressure calibration curves ranging from 0.4 to>30 GPa for various types of LVP installed at the Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing,including piston–cylinder,cubic,and multi-anvil presses.The results provide a unified and traceable pressure reference for highpressure experiments conducted at HPSTAR,while also offering technical guidance and calibration standards for other researchers utilizing similar LVP systems,thereby enabling more consistent comparison between different laboratories.This work facilitates the advancement of LVP research toward broader applications in higher-pressure regimes.
文摘The application of the Soil and Water Assessment Tool (SWAT) to the Olifants Basin in South Africa was the focus of our study with emphasis on calibration, validation and uncertainty analysis. The Basin was discretized into 23 sub-basins and 226 Hydrologic Response Units (HRUs) using 3 arc second (90 m × 90 m) pixel resolution SRTM DEM with stream gauge B7H015 as the Basin outlet. Observed stream flow data at B7H015 were used for model calibration (1988-2001) and validation (2002-2013) using the split sample approach. Relative global sensitivity analysis using SUFI-2 algorithm was used to determine sensitive parameters to stream flow for calibration of the model. Performance efficiency of the Olifants SWAT model was assessed using Nash-Sutcliffe (NSE), coefficient of determination (R<sup>2</sup>), Percent Bias (PBIAS) and Root Mean Square Error-Observation Standard deviation Ratio (RSR). Sensitivity analysis revealed in decreasing order of significance, runoff curve number (CN2), alpha bank factor (ALPHA_BNK), soil evaporation compensation factor (ESCO), soil available water capacity (SOIL_AWC, mm H<sub>2</sub>O/mm soil), groundwater delay (GW_ DELAY, days) and groundwater “revap” coefficient (GW_REVAP) to be the most sensitive parameters to stream flow. Analysis of the model during the calibration period gave the following statistics;NSE = 0.88;R<sup>2</sup> = 0.89;PBIAS = -11.49%;RSR = 0.34. On the other hand, statistics during the validation period were NSE = 0.67;R<sup>2 </sup>= 0.79;PBIAS = -20.69%;RSR = 0.57. The observed statistics indicate the applicability of the SWAT model in simulating the hydrology of the Olifants Basin and therefore can be used as a Decision Support Tool (DST) by water managers and other relevant decisions making bodies to influence policy directions on the management of watershed processes especially water resources.
文摘Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using aggregated or limited data. If their calibration is regularly mentioned in the literature, their validation is barely discussed. In this paper, several modal choice model specifications that make only use of explanatory variables available at the network level are described and applied to a large scale case. A validation exercise is performed at three levels of aggregation. The paper is designed from a strategic transport planning perspective, and does not present new modal choice formulations or assignment procedures. Its main added value is the focus on calibration and validation considerations. Despite the limited explanatory information used, the global performance of the best models can be considered as satisfactory. However, the quality of the models varies from mode to mode, the use of railway transport being the most difficult to predict without more specific input.
基金partly supported by the French National“Investment for the future”funding programme.
文摘Background: In the context of a nuclear reactor accident, thyroid is the main target organ of radioactive iodines. To avoid as much as possible thyroid disorders or even cancer development, it is recommended to administer a single dose of potassium iodide to people at risk of exposure. Nevertheless, the Fukushima Dai-ichi disaster has pointed out many questions about the conditions of stable iodine prophylaxis implementation highlighting the need for reflection further revision of the actual “iodine doctrine”. Therefore, providing useful data is required notably through the implementation of animal experiments to strengthen current knowledge and to edit new recommendations. Methods: Urinary iodine constitutes a very good indicator to investigate the function of thyroid, its interpretation demands reliable analyses. Prior to perform animal experiments, two calibration methods were designed by our lab and compared together (standard addition and external calibration) to assess the urinary concentration of stable iodine in urine by ICP-MS. They were validated based on several key parameters especially linearity, accuracy and limits of detection (LOD) and quantification (LOQ). Results: The results were nicely satisfying. Indeed, both calibration methods have indicated very good coefficients of correlations, accuracies with low expanded relative uncertainties were obtained. The estimated LOD in the sample for standard addition method and external calibration were fully acceptable, 0.39 μg·L-1 and 0.35 μg·L-1, respectively. All performance criteria have been thus fulfilled successfully. The established methods were proven to be accurate, robust and sensitive. Once validated, both calibration methods were applied to rat urine samples and the results of z-score and Wilcoxon W test concluded that there were no statistically significant differences between both methods.
文摘Maize is an emerging important crop in Bangladesh because of its high yield potential and economic profitability compared to rice and wheat crops. There is a need to understand the growth and yield behavior of this crop in varying production environments of Bangladesh. Crop model such as Decision Support System For Agro-technology Transfer (DSSAT) version 4.6 (DSSAT hereafter) can be utilized cost effectively to study the performances of maize under different production environments. It needs to calibrate and validate DSSAT model for commonly cultivated maize cultivars in Bangladesh and subsequently take the model to various applications, including inputs and agronomic management options and climate change that impacts analyses. So, the present study was undertaken to firstly calibrate DSSAT model for popular four hybrid maize cultivars (BARI Hybrid Maize-7, BARI Hybrid Maize-9, Pioneer 30B07 and NK-40). Subsequently, it proceeded with the validation with independent field data sets for evaluating their growth performances. The genetic coefficients for these cultivars were evaluated by using Genotype coefficient calculator (GENCALC) and Generalized likelihood uncertainty estimation (GLUE) module of DSSAT on the basis of first season experiment. The performance of the model was satisfactory and within the significant limits. After calibration, the model was tested for its performance through validation procedure by using second season data. The model performed satisfactorily through phenology, biomass, leaf area index (LAI) and grain yield. Phenology, as estimated through days to flower initiation and maturity, was in good agreement, although simulated results were slightly over predicted compared to observed values but within the statistical significance limit...when compared with observed values at specific growth stages of the crop. The final yield values (10.12 to 10.59 t·ha-1) were in close agreement with the observed values (10.16 to 10.94 t·ha-1), as the percentage error was within tolerable limit (0.39% to 6.81%). The model has been successfully calibrated and validated for Gazipur environment and now can be used for climate change impact studies for similar environments in Bangladesh.
文摘Soybean and sunflower are summer annuals that can be grown as an alternative to corn and may be particularly useful in organic production systems for forage in addition to their traditional use as protein and/or oil yielding crops. Rapid and low cost methods of analyzing plant forage quality would be helpful for nutrition management of livestock. We developed and validated calibration models using Near-infrared Reflectance Spectroscopic (NIRS) analysis for 27 different forage quality parameters of organically grown sunflower and soybean leaves or reproductive parts. Crops were managed under conventional tillage or no-till with a cover crop of wheat before soybean and rye-crimson clover before sunflower. From a population of 120 samples from both crops, covering multiple sampling dates within the treatments, calibration models were developed utilizing spectral information covering both visible and NIR region of 61 - 85 randomly chosen samples using modified partial least-squares (MPLS) regression with internal cross validation. Within MPLS protocol, we compared nine different math treatments on the quality of the calibration models. The math treatment “2,4,4,1” yielded the best quality models for all but starch and simple sugars (r2 = 0.699 - 0.999;where the 1st digit is the number of the derivative with 0 for raw spectra, 1 for first derivative, and 2 for second derivative, the 2nd digit is the gap over which the derivative is calculated, the 3rd digit is the number of data points in a running average or smoothing, and the 4th digit is the second smoothing). Prediction of an independent validation set of 28-35 samples with these models yielded excellent agreement between the NIRS predicted values and the reference values except for starch (r2 = 0.8260 - 0.9990). The results showed that the same model was able to adequately quantify a particular forage quality of both crops managed under different tillage treatments and at different stages of growth. Thus, these models can be reliably applied in the routine analysis of soybean and sunflower forage quality for the purposes of livestock nutrient management decisions.
文摘The hydrologic simulation of a catchment area, described as the transformation of rainfall into runoff, generally uses hydrologic model. This work opts for the global conceptual hydrologic model GR2M, a monthly time step model, to study the Kouilou-Niari basin, the second most important ones of the Republic of Congo. This includes two parameters to model the hydrologic behavior of a catchment area. The choice of the conceptual model GR2M is justified by the reduced number of parameters and the monthly time scale. The objective of this study is to determine the characteristic parameters of the GR2M model, by a calibrating and a validating procedure. The use of these parameters enables to follow the evolution of the water resources from the climatic variables. It has been first carried out a characterization of some physical, geological and climatic factors governing the flow, by dealing with the main climatic variables which constitute the inputs of the hydrologic model. Then, a hydrologic rainfall-runoff modeling allows to calibrate and validate the model at monthly time scale. Taking into account the number of parameters involved in hydrologic processes and the complexity of the cathment area, this model gives acceptable results throughout the Kouilou-Niari basin. The values of the Nash-Sutcliffe criterion and those of the correlation coefficient obtained are greater than 80% in validation, which explains the performance and robustness of the GR2M model on this basin.
