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- 实验方案
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MultOpt++: a fast regression-based model for the development of compositions with high robustness against scatter of element concentrations
摘要： Alloys-by-design is a term used to describe new alloy development techniques based on numerical simulation. These approaches are extensively used for nickel-base superalloys to increase the chance of success in alloy development. During alloy production of numerically optimized compositions, unavoidable scattering of the element concentrations occurs. In the present paper, we investigate the effect of this scatter on the alloy properties. In particular, we describe routes to identify alloy compositions by numerical simulations that are more robust than other compositions. In our previously developed alloy development program package MultOpt, we introduced a sensitivity parameter that represents the influence of alloying variations on the final alloy properties in the post-optimization process, because the established sensitivity calculations require high computational effort. In this work, we derive a regression-based model for calculating the sensitivity that only requires one-time calculation of the regression coefficients. The model can be applied to any function with nearly linear behavior within the uncertainty range. The model is then successfully applied to the computational alloys-by-design work flow to facilitate alloy selection using the sensitivity of a composition owing to the inaccuracies in the manufacturing process as an additional minimization goal.
关键词： sensitivity,CALPHAD,regression analysis,alloys-by-design,superalloys
更新于2025-09-23 15:23:52
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A New Algorithm for Blood Flow Measurement Based on The Doppler Flow Spectrogram
摘要： The blood ?ow is traditionally obtained by multiplying the cross sectional area of the blood vessel and the average blood speed in the cross section, or is given by the integral of the product of the cross section and blood velocity of each element. However, both methods are affected greatly by the measurement precision of the area and velocity. A new algorithm, which is based on the Doppler blood ?ow spectrogram, is proposed to measure the blood ?ow in this paper. In the algorithm, the blood ?ow is calculated according to the double integral of a Doppler blood ?ow spectrogram. To verify the feasibility of the proposed algorithm, experiments have been performed on the Doppler blood-mimicking system KS205D?1 using the SonixTouch ultrasonic system. In addition, linear-regression analysis is carried out to observe the correlation factors between the experimental values and real values of different ?ow rates. Experimental results show that the calculated values and real values correlate signi?cantly (r > 0.969, P < 0.0000001). Experimental results both on males and females also veri?ed the proposed algorithm (r > 0.915, P < 0.00053). Hence the proposed algorithm is proven effective for relative mean blood ?ow measurement. Due to the special structure of the human brain, it is dif?cult to measure the cross sectional area of blood vessel with ultrasound imaging. In this algorithm, there is no need to measure the cross sectional area of the blood vessel. Therefore, the proposed algorithm has the potential to be a new method for clinical ultrasonic blood ?ow measurement, especially cerebral blood ?ow measurement.
关键词： Blood ?ow measurement,Doppler blood-mimicking system,Doppler spectrogram,linear-regression analysis
更新于2025-09-23 15:22:29
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Ina??season potato yield prediction with active optical sensors
摘要： Crop yield prediction is a critical measurement, especially in the time when parts of the world are suffering from farming issues. Yield forecasting gives an alert regarding economic trading, food production monitoring, and global food security. This research was conducted to investigate whether active optical sensors could be utilized for potato (Solanum tuberosum L.) yield prediction at the mid.le of the growing season. Three potato cultivars (Russet Burbank, Superior, and Shepody) were planted and six rates of N (0, 56, 112, 168, 224, and 280 kg ha?1), ammonium sulfate, which was replaced by ammonium nitrate in the 2nd year, were applied on 11 sites in a randomized complete block design, with four replications. Normalized difference vegetation index (NDVI) and chlorophyll index (CI) measurements were obtained weekly from the active optical sensors, GreenSeeker (GS) and Crop Circle (CC). The 168 kg N ha?1 produced the maximum potato yield. Indices measurements obtained at the 16th and 20th leaf growth stages were significantly correlated with tuber yield. Multiple regression analysis (potato yield as a dependent variable and vegetation indices, NDVI and CI, as independent variables) could make a remarkable improvement to the accuracy of the prediction model and increase the determination coefficient. The exponential and linear models showed a better fit of the data. Soil organic matter content increased the yield significantly but did not affect the prediction models. The 18th and 20th leaf growth stages are the best time to use the sensors for yield prediction.
关键词： sensor technology,petiole sampling,potato,prediction models,multiple regression analysis,Yield prediction,nitrogen loss
更新于2025-09-23 15:21:01
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Quantitative in situ mapping of elements in deep-sea hydrothermal vents using laser-induced breakdown spectroscopy and multivariate analysis
摘要： This study describes a method to quantify the chemical composition of deep-sea hydrothermal deposits in situ using laser-induced breakdown spectroscopy (LIBS). Partial least squares (PLS) regression analysis is applied to spectra obtained using a long laser pulse with a duration of 150 ns. The number of measurements needed to address the spatial heterogeneity of samples is determined through high-resolution mapping of the elemental distribution in rock samples. PLS applied to laboratory measured seawater-submerged samples achieved an average relative error (RE) of 25% for Cu, Pb, and Zn compared to benchmark concentration values in cross-validation and validation studies, where both the benchmark concentration values and LIBS spectral data are made available with this publication. The PLS model was applied to LIBS signals obtained in situ from hydrothermal deposits at 1000 m depth in the ocean. The results show that target inhomogeneity limits the accuracy of the surface LIBS measurements compared to benchmark values from bulk analysis of samples. Making multiple measurements with small position offsets at each location improves the accuracy of estimates compared to an equivalent number of measurements at a single position. Maps of element distribution generated using quantified in situ data demonstrate how chemical survey outputs can be generated by combining LIBS with multivariate analysis. This enables real-time chemical feedback during deep-sea operations and chemical surveys in situations or with platforms where sample recovery is not possible.
关键词： Multivariate analysis,Laser-induced breakdown spectroscopy (LIBS),Deep-sea explorations,In situ chemical analysis,Seafloor mineral resources,Partial least squares regression analysis
更新于2025-09-23 15:19:57
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50-GHz Repetition Gain Switching Using A Cavity-enhanced DFB Laser Assisted By Optical Injection Locking
摘要： This paper introduces the (cid:2) counter, a frequency counter—i.e., a frequency-to-digital converter—based on the linear regression (LR) algorithm on time stamps. We discuss the noise of the electronics. We derive the statistical properties of the (cid:2) counter on rigorous mathematical basis, including the weighted measure and the frequency response. We describe an implementation based on a system on chip, under test in our laboratory, and we compare the (cid:2) counter to the traditional (cid:3) and (cid:4) counters. The LR exhibits the optimum rejection of white phase noise, superior to that of the (cid:3) and (cid:4) counters. White noise is the major practical problem of wideband digital electronics, both in the instrument internal circuits and in the fast processes, which we may want to measure. With a measurement time τ , the variance is proportional to 1/τ 2 for the (cid:3) counter, and to 1/τ 3 for both the (cid:4) and (cid:2) counters. However, the (cid:2) counter has the smallest possible variance, 1.25 dB smaller than that of the (cid:4) counter. The (cid:2) counter ?nds a natural application in the measurement of the parabolic variance, described in the companion article in this Journal [vol. 63 no. 4 pp. 611–623, April 2016 (Special Issue on the 50th Anniversary of the Allan Variance), DOI 10.1109/TUFFC.2015.2499325].
关键词： noise,regression analysis,frequency measurement,instrumentation and measurement,time measurement,phase noise,Frequency estimation
更新于2025-09-23 15:19:57
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Brain MR Kurtosis Imaging Study: Contrasting Gray and White Matter
摘要： This paper mainly focuses on characterization of different brain tissues such as White and Gray matter (WM and GM) using the relation between Diffusion Tensor Imaging and Diffusion Kurtosis Imaging parameters. Both Diffusion Tensor Imaging and Diffusion Kurtosis Imaging are the extension of Diffusion Weighted Imaging, which are widely applied for analysing micro fibre structure of human organs non-invasively. Diffusion Tensor Imaging assumes that the water diffusion is in Gaussian nature and Diffusion Kurtosis Imaging accounts the deviation of the Gaussian nature. This study, conducted a correlation and regression analysis between different parametric maps generated from Diffusion Kurtosis Images. For this we have chosen 200 regions of interest pixels drawn from brain MRIs. From the results, it is observed that there is a significant variation in the correlation results between Axial Diffusion and Kurtosis Fractional Anisotropy maps of Gray matter and White matter tissues. This can be employed for enhancing accuracy in MRI segmentation techniques and also as a potential tool for Neuro degenerative disease detection.
关键词： Gray matter,Diffusion Tensor Imaging,White matter,brain MRI,Diffusion Kurtosis Imaging,Correlation analysis,Regression analysis
更新于2025-09-19 17:15:36
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Estimation of Global Solar Radiation using Modifed Angstrom Empirical formula on the basis of Meterological parameters in Himalaya Region Pokhara, Nepal
摘要： This research work proposes the coefficient equation of modified Angstrom model using sunshine hour and meteorological parameters for the estimation of global solar radiation in Himalaya Region Pokhara (28.220N, 83.320 E), Nepal. This site is about 800.0 m above from the sea level lying just 20.0 km south of the Machhaputre Himalayas. The model coefficients a and b obtained in this research are 0.43 and 0.23 respectively. The performance parameters of the model are: Root Mean Square Error RMSE = 0.13 MJ/m2/day, Mean Bias Error MBE= 0.02 MJ/m2/day Mean Percentage MPE= 5 percent and coefficient of determination R2= 0.70.
关键词： empirical formula,global solar radiation,regression analysis,sunshine hour,clearness index
更新于2025-09-19 17:15:36
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Underwater laser micro-milling of fine-grained aluminium and the process modelling by machine learning
摘要： Nanosecond-pulsed laser ablation is often accompanied by adverse thermal effects such as oxidation, debris recast and burr formation. To reduce these effects, in this paper, the authors present the underwater laser milling process using RSA-905 fine-grained aluminium as the target material for the first time. The results show that channels up to 200 μm in width, 700 μm depth and bottom roughness around 1 μm Ra could be fabricated with reduced thermal effects. By conducting multi- and single-factor experiments, empirical models relating the laser processing parameters to the key dimensions of channels were derived using artificial neural network (ANN) algorithm and polynomial regression (PR), and the models’ accuracies were evaluated. Based on the models, the cross-section profile of a channel subject to a given set of processing parameters can be predicted. The process can serve as a pre-treatment technique of mechanical milling such that the tool life will be extended and the profile of a desired feature can be precisely defined.
关键词： Regression analysis,Channel fabrication,Machine learning,Underwater laser machining,Burr-free
更新于2025-09-19 17:13:59
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Improving laser cutting quality of polymethylmethacrylate sheet: experimental investigation and optimization
摘要： Motivated by the need to enhance the kerf quality during cutting of Poly(methyl methacrylate) (PMMA) sheets using pulsed CO2 laser beam, this study presents an experimental investigation and optimization of laser cutting parameters including cutting speed, assisted gas pressure, laser beam power, and sheet thickness. The kerf quality characteristics including the top kerf width, bottom kerf width, and kerf taper have been considered as the process responses and have been measured using polarized light microscope. The experiments were designed and planned using Taguchi L18 orthogonal array with a mixed design. The effects of different cutting parameters on the kerf characteristics have been statistically analyzed using analysis of variance technique (ANOVA). The obtained results revealed that any increase in cutting parameters will result in increasing the top and the bottom kerf widths, while increasing cutting speed or laser power results in increasing the kerf taper. Second order regression models have been developed to model different kerf characteristics as functions of the process parameters. Genetic algorithm (GA) has been used to select the optimal cutting parameters using the developed regression model as an objective function to minimize the kerf taper. A considerable improvement in kerf quality has been achieved and the obtained results have been verified using confirmation experiments. The application of the proposed approach is capable to reduce the kerf taper from 1.92? to 0.02? while maintaining the minimum kerf width at a reasonable value (less than 0.5 mm).
关键词： Genetic algorithm,PMMA,Regression analysis,Taguchi method,Laser cutting,kerf geometry
更新于2025-09-16 10:30:52
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Effect of Laser Process Parameters on Laser Assisted Machining Of Inconel 718: Statistical – Regression Analyses
摘要： This paper discusses the effect of laser-assisted process parameters on cutting forces and surface temperature during laser assisted machining (LAM) of Inconel 718. The heat source used for pre-heating the surface is Nd:YAG laser source. Cutting speed, feed rate and laser power are the process parameter assessor for cutting force and cutting temperature. The experiments are planned and results are collected based on Taguchi’s L27 orthogonal design. The factor effect on output responses are analysed using a main effect plots (2D) and its significance is perceived from analysis of variance (ANOVA). Results reveal that cutting speed bags a maximum contribution of 56%, followed by cutting speed * feed rate as 24%, feed rate * laser power as 10.5 % and feed rate as 10%. Finally, the benefit of LAM was shown by 55% decrease in feed force (Fx), 50% decrease in thrust force (Fy) and 60% decrease in cutting force (Fz), as compared to those of the conventional machining. Additionally, it is also recommended to employ a work surface temperature in the range of 750?C–887?C during LAM of this Inconel 718 alloy to have maximum process benefits. The developed regression model reveals the goodness of fit with experimental data has high determination coefficient i.e. R2 = 0.91 for tangential force and 0.71 for surface temperature.
关键词： regression analysis,Statistical analysi,cutting forces,surface temperature
更新于2025-09-16 10:30:52