Articles de revues : « Characteristic estimation »

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SINGH, RAJESH. « Variance Estimation Using Quality Characteristic ». Mathematical Journal of Interdisciplinary Sciences 5, n^o 2 (5 mars 2017) : 143–49. http://dx.doi.org/10.15415/mjis.2017.52011.

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Fredlund, Delwyn G., Daichao Sheng et Jidong Zhao. « Estimation of soil suction from the soil-water characteristic curve ». Canadian Geotechnical Journal 48, n^o 2 (février 2011) : 186–98. http://dx.doi.org/10.1139/t10-060.

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Soil-water characteristic curves (SWCCs) are routinely used for the estimation of unsaturated soil property functions (e.g., permeability functions, water storage functions, shear strength functions, and thermal property functions). This paper examines the possibility of using the SWCC for the estimation of in situ soil suction. The paper focuses on the limitations of estimating soil suctions from the SWCC and also suggests a context under which soil suction estimations should be used. The potential range of estimated suction values is known to be large because of hysteresis between drying and wetting SWCCs. For this, and other reasons, the estimation of in situ suctions from the SWCC has been discouraged. However, a framework is suggested in this paper for estimating the median value for in situ soil suction along with a likely range of soil suction values (i.e., maximum and minimum values). The percentage error in the estimation of soil suction from the SWCC is shown to be lowest for sand soils and highest for clay soils.

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Utami, Bernadhita Herindri Samodera, Dwi Herinanto et Miswan Gumanti. « Characteristic Estimator of Interval-Censored Binomial Data and Its Application ». Jurnal Varian 6, n^o 1 (13 novembre 2022) : 1–10. http://dx.doi.org/10.30812/varian.v6i1.1847.

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This study aims to determine the estimation of interval-censored data with a special distribution, namely the binomial distribution. This research is using quantitative methods, the steps are estimating parameters on the interval-censored binomial distribution using the Maximum Likelihood Estimation method. The second step shows the properties of the estimator on the interval-censored binomial distribution. The last is to determine the parameter estimation of interval-censored data from the binomial distribution in survival analysis and provide an example of research containing interval-censored observations which will then be used as a case study. The results showed that the estimator is a sufficient statistic, meaning that it is unbiased. The case study was conducted using interval-censored data regarding the study of ninety-four breast cancer patients to see which group survived longer (survival value) of the two treatments, namely patients who underwent radiotherapy alone and patients who underwent radiotherapy followed by adjuvant chemotherapy.

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Carrasco, Marine, et Rachidi Kotchoni. « EFFICIENT ESTIMATION USING THE CHARACTERISTIC FUNCTION ». Econometric Theory 33, n^o 2 (22 février 2016) : 479–526. http://dx.doi.org/10.1017/s0266466616000025.

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The method of moments procedure proposed by Carrasco and Florens (2000) permits full exploitation of the information contained in the characteristic function and yields an estimator which is asymptotically as efficient as the maximum likelihood estimator. However, this estimation procedure depends on a regularization or tuning parameterαthat needs to be selected. The aim of the present paper is to provide a way to optimally chooseαby minimizing the approximate mean square error (AMSE) of the estimator. Following an approach similar to that of Donald and Newey (2001), we derive a higher-order expansion of the estimator from which we characterize the finite sample dependence of the AMSE onα. We propose to select the regularization parameter by minimizing an estimate of the AMSE. We show that this procedure delivers a consistent estimator ofα. Moreover, the data-driven selection of the regularization parameter preserves the consistency, asymptotic normality, and efficiency of the CGMM estimator. Simulation experiments based on a CIR model show the relevance of the proposed approach.

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Derechennik, Stanislav S., et Viktar V. Tur. « Adaptive Estimation of the In Situ Characteristic Concrete Strength ». Solid State Phenomena 292 (juin 2019) : 257–63. http://dx.doi.org/10.4028/www.scientific.net/ssp.292.257.

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For calculation of existing concrete structures on the basis of the partial factor format, the main representative value is the actual in-situ characteristic value of the concrete strength. When samples are tested, the concrete in-situ strength of the structure shall be determined, statistically if possible, from the test results. In accordance with EN 1990 the 5% percentile value is calculated on the basis of a unilaterally limited constant confidence level. It was found the in some case, estimation of the in-situ characteristic concrete strength taking a constant confidence level does not allow to adequately assess the reliability of the existing structures. A new estimator based on non-parametric statistical method was proposed for estimating of the in-situ characteristic concrete strength with a given arbitrary confidence level. The procedure that was proposed allows one to re-establish of the estimator pdf even with a very limited sample size. It is established, that the choice of the confidence level of the estimator should be based on the average reliability of the structure.

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Kärkkäinnen, Salme, Antti Penttinen, Nikolai G. Ushakov et Alexandra P. Ushakova. « Estimation of orientation characteristic of fibrous material ». Advances in Applied Probability 33, n^o 3 (septembre 2001) : 559–75. http://dx.doi.org/10.1239/aap/1005091352.

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A new statistical method for estimating the orientation distribution of fibres in a fibre process is suggested where the process is observed in the form of a degraded digital greyscale image. The method is based on line transect sampling of the image in a few fixed directions. A well-known method based on stereology is available if the intersections between the transects and fibres can be counted. We extend this to the case where, instead of the intersection points, only scaled variograms of grey levels along the transects are observed. The nonlinear estimation equations for a parametric orientation distribution as well as a numerical algorithm are given. The method is illustrated by a real-world example and simulated examples where the elliptic orientation distribution is applied. In its simplicity, the new approach is intended for industrial on-line estimation of fibre orientation in disordered fibrous materials.

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Knight, John L., et Jun Yu. « EMPIRICAL CHARACTERISTIC FUNCTION IN TIME SERIES ESTIMATION ». Econometric Theory 18, n^o 3 (15 mai 2002) : 691–721. http://dx.doi.org/10.1017/s026646660218306x.

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Because the empirical characteristic function (ECF) is the Fourier transform of the empirical distribution function, it retains all the information in the sample but can overcome difficulties arising from the likelihood. This paper discusses an estimation method via the ECF for strictly stationary processes. Under some regularity conditions, the resulting estimators are shown to be consistent and asymptotically normal. The method is applied to estimate the stable autoregressive moving average (ARMA) models. For the general stable ARMA model for which the maximum likelihood approach is not feasible, Monte Carlo evidence shows that the ECF method is a viable estimation method for all the parameters of interest. For the Gaussian ARMA model, a particular stable ARMA model, the optimal weight functions and estimating equations are given. Monte Carlo studies highlight the finite sample performances of the ECF method relative to the exact and conditional maximum likelihood methods.

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Kärkkäinnen, Salme, Antti Penttinen, Nikolai G. Ushakov et Alexandra P. Ushakova. « Estimation of orientation characteristic of fibrous material ». Advances in Applied Probability 33, n^o 03 (septembre 2001) : 559–75. http://dx.doi.org/10.1017/s0001867800010995.

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A new statistical method for estimating the orientation distribution of fibres in a fibre process is suggested where the process is observed in the form of a degraded digital greyscale image. The method is based on line transect sampling of the image in a few fixed directions. A well-known method based on stereology is available if the intersections between the transects and fibres can be counted. We extend this to the case where, instead of the intersection points, only scaled variograms of grey levels along the transects are observed. The nonlinear estimation equations for a parametric orientation distribution as well as a numerical algorithm are given. The method is illustrated by a real-world example and simulated examples where the elliptic orientation distribution is applied. In its simplicity, the new approach is intended for industrial on-line estimation of fibre orientation in disordered fibrous materials.

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Cadiou, J. C., et A. El Hadri. « Transversal tyre road characteristic estimation ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 218, n^o 10 (octobre 2004) : 1099–110. http://dx.doi.org/10.1177/095440700421801004.

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TAKASE, Kazuto, et Naoya HARA. « ESTIMATION OF VISUAL CHARACTERISTIC VALUES BASED ON BCD LUMINANCE ESTIMATION METHODS REFLECTING OPTICAL CHARACTERISTICS ». Journal of Environmental Engineering (Transactions of AIJ) 88, n^o 805 (1 mars 2023) : 148–53. http://dx.doi.org/10.3130/aije.88.148.

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Wilak, Kamil. « Autocorrelation of error estimations in Labour Force Surveys ». Wiadomości Statystyczne. The Polish Statistician 60, n^o 6 (29 juin 2015) : 31–40. http://dx.doi.org/10.5604/01.3001.0016.0826.

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Rotating panel used in the Labour Force Survey (LFS) causes correlation possibility of estimations of labor markets errors. Knowledge of autocorrelation is important in the context of the trend estimation of labor market parameters. Dismissal of autocorrelation can result in the trend curve it will be fraught with volatility, characteristic of auto-regression processes. Estimation errors are not observable, thus it is not possible to estimate the autocorrelation coefficients by conventional estimators. This paper describes the adaptation of methods for estimating the errors of autocorrelation coefficients (proposed by Pfeffermanna et al.), The rotational scheme in LFS. Then, this method was used to estimate the autocorrelation coefficients in error estimation of the unemployment rate in the province. Greater Poland for six domains defined by gender and age.

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Поленова, С., et S. Polenova. « To the Concept «Estimation» in Accounting ». Auditor 3, n^o 9 (4 octobre 2017) : 18–25. http://dx.doi.org/10.12737/article_59bf8ba8761a68.13638034.

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On the base of the studies, called on scientist in sphere of the concept «estimation» in accounting, in article it is executed attempt to give its determination and off er the use of the miscellaneous type estimations in the purpose of the accounting, accounting and financial reporting, coming from their integer and such characteristic of the estimation as express sing and income sing.

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Sheng, Lin, Zhongfeng Xu, Yi Tan et Bo Ma. « Mass estimation method of loose parts based on function model ». Journal of Physics : Conference Series 2184, n^o 1 (1 mars 2022) : 012005. http://dx.doi.org/10.1088/1742-6596/2184/1/012005.

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Abstract The nuclear main pump has a complex structure and contains a large number of components. With the continuous flow of the primary circuit coolant, there is a risk of loosening and falling off of the components in the reactor. The existence of loose parts in the reactor makes the reactor operation a safety hazard. Accurate mass estimation of the loose parts is conductive to quickly judge the degree of the failure of loose parts, provide effective suggestions for the subsequent maintenance of the reactor and ensure the safety of reactor operation. The existing mass estimation methods have problems of large errors and poor consistency. This article proposes a method for estimating the mass of loose parts by establishing a functional relationship model based on signal characteristic value. The characteristic value of the signal is constructed by extracting the Root Mean Square value and the main frequency of the shock signal, and then the functional relationship between the quality of the loose part and the characteristic value of the signal is established, which is used to estimate the mass of the loose part. The experimental results show that the method proposed in this paper has the characteristics of small estimation error and good consistency, which can meet the needs of practical engineering applications.

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Hosseinipanah, Mirshahram, et Qun Wu. « Characteristic Estimation of Artificial Magnetic Conductors ». Electromagnetics 30, n^o 5 (29 juin 2010) : 435–47. http://dx.doi.org/10.1080/02726343.2010.483934.

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Garcia, R. B., M. W. N. Lobão et C. T. Andrade. « Estimation of Agarose Network Characteristic Parameters ». Polymer Reaction Engineering 2, n^o 1-2 (janvier 1994) : 1–15. http://dx.doi.org/10.1080/10543414.1994.10744447.

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Cattaneo, Matias D., Richard K. Crump, Max H. Farrell et Ernst Schaumburg. « Characteristic-Sorted Portfolios : Estimation and Inference ». Review of Economics and Statistics 102, n^o 3 (juin 2020) : 531–51. http://dx.doi.org/10.1162/rest_a_00883.

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Portfolio sorting is ubiquitous in the empirical finance literature, where it has been widely used to identify pricing anomalies. Despite its popularity, little attention has been paid to the statistical properties of the procedure. We develop a general framework for portfolio sorting by casting it as a nonparametric estimator. We present valid asymptotic inference methods and a valid mean square error expansion of the estimator leading to an optimal choice for the number of portfolios. In practical settings, the optimal choice may be much larger than the standard choices of five or ten. To illustrate the relevance of our results, we revisit the size and momentum anomalies.

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Abdushukurov, A. A., et F. Sh Norboev. « Kernel Estimation of a Characteristic Function ». Journal of Mathematical Sciences 220, n^o 6 (19 décembre 2016) : 643–49. http://dx.doi.org/10.1007/s10958-016-3207-1.

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Li, Chunxiao, et Jiangming Kan. « Illumination estimation based on image characteristic ». Journal of Electronic Imaging 27, n^o 04 (5 juillet 2018) : 1. http://dx.doi.org/10.1117/1.jei.27.4.043003.

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Zhang, Ying, et Todd A. Alonzo. « Estimation of the volume under the receiver-operating characteristic surface adjusting for non-ignorable verification bias ». Statistical Methods in Medical Research 27, n^o 3 (17 janvier 2018) : 715–39. http://dx.doi.org/10.1177/0962280217742541.

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The receiver-operating characteristic surface is frequently used for presenting the accuracy of a diagnostic test for three-category classification problems. One common problem that can complicate the estimation of the volume under receiver-operating characteristic surface is that not all subjects receive the verification of the true disease status. Estimation based only on data from subjects with verified disease status may be biased, which is referred to as verification bias. In this article, we propose new verification bias correction methods to estimate the volume under receiver-operating characteristic surface for a continuous diagnostic test. We assume the verification process is missing not at random, which means the missingness might be related to unobserved clinical characteristics. Three classes of estimators are proposed, namely, inverse probability weighted, imputation-based, and doubly robust estimators. A jackknife estimator of variance is derived for all the proposed volume under receiver-operating characteristic surface estimators. The finite sample properties of the new estimators are examined via simulation studies. We illustrate our methods with data collected from Alzheimer’s disease research.

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Felipe da Silva André, Marcos, et Thiago de Souza Carnavale. « Comparison between Soil-Water Characteristic Curves based on filter paper method and grain-size distribution/volume-mass prediction : An evaluation of input data stemmed from hydrometer and Cilas grain-size analyser ». E3S Web of Conferences 195 (2020) : 03027. http://dx.doi.org/10.1051/e3sconf/202019503027.

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The current paper aims to present a comparison between soil-water characteristic curves based on the filter paper method and on a volume-mass estimation. Additionally, this research consists in comparing grain size distributions by sieving/hydrometer and by sieving/Cilas (particle-size analyser model 1092), when it comes to determining the soil-water characteristic curves by a volume-mass prediction on the Soil Vision software. As materials, were used two sets of colluvial soils sampled at the Campus Quinta do Paraiso -Centro Universitário Serra dos Órgãos (UNIFESO), Teresópolis – Brazil. The results showed that the soil-water characteristic curves related to the filter paper method or grain size distribution estimation are different. However, the tests performed by sieving/Cilas are more efficient than the results based on sieving/hydrometer, concerning its uses as input data for soil-water characteristic curves estimations. In conclusion, even considering the estimation method was not able to depict the same results such as obtained by the filter paper method, the use of Cilas is a procedure that can improve the quality of the predicted soil-water characteristic curve.

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Yang, Jian, Yangyang Zhang, Lin Du, Xiuguo Liu, Shuo Shi et Biwu Chen. « Improving the Selection of Vegetation Index Characteristic Wavelengths by Using the PROSPECT Model for Leaf Water Content Estimation ». Remote Sensing 13, n^o 4 (23 février 2021) : 821. http://dx.doi.org/10.3390/rs13040821.

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Equivalent water thickness (EWT) is a major indicator for indirect monitoring of leaf water content in remote sensing. Many vegetation indices (VIs) have been proposed to estimate EWT based on passive or active reflectance spectra. However, the selection of the characteristics wavelengths of VIs is mainly based on statistical analysis for specific vegetation species. In this study, a characteristic wavelength selection algorithm based on the PROSPECT-5 model was proposed to obtain characteristic wavelengths of leaf biochemical parameters (leaf structure parameter (N), chlorophyll a + b content (Cab), carotenoid content (Car), EWT, and dry matter content (LMA)). The effect of combined characteristic wavelengths of EWT and different biochemical parameters on the accuracy of EWT estimation is discussed. Results demonstrate that the characteristic wavelengths of leaf structure parameter N exhibited the greatest influence on EWT estimation. Then, two optimal characteristics wavelengths (1089 and 1398 nm) are selected to build a new ratio VI (nRVI = R1089/R1398) for EWT estimation. Subsequently, the performance of the built nRVI and four optimal published VIs for EWT estimation are discussed by using two simulation datasets and three in situ datasets. Results demonstrated that the built nRVI exhibited better performance (R2 = 0.9284, 0.8938, 0.7766, and RMSE = 0.0013 cm, 0.0022 cm, 0.0030 cm for ANGERS, Leaf Optical Properties Experiment (LOPEX), and JR datasets, respectively.) than that the published VIs for EWT estimation. It is demonstrated that the built nRVI based on the characteristic wavelengths selected using the physical model exhibits desirable universality and stability in EWT estimation.

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Honda, T., H. Kawanishi, T. Sakaguchi, F. Koyama et K. Iga. « Characteristic Temperature Estimation for GaN-Based Lasers ». MRS Internet Journal of Nitride Semiconductor Research 4, S1 (1999) : 548–53. http://dx.doi.org/10.1557/s1092578300003021.

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We have estimated the characteristic temperature T0 of GaN-based vertical-cavity surface-emitting lasers. The density matrix theory including intraband relaxation broadening has been taken into account. The estimated T0 is about 300 K, which suggests a good temperature characteristic in GaN-based lasers.

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Wolfenden, A., et S. Slatcher. « Estimation of Characteristic Values of Fracture Toughness ». Journal of Testing and Evaluation 18, n^o 3 (1990) : 141. http://dx.doi.org/10.1520/jte12468j.

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Yu, Jun. « Empirical Characteristic Function Estimation and Its Applications ». Econometric Reviews 23, n^o 2 (31 décembre 2004) : 93–123. http://dx.doi.org/10.1081/etc-120039605.

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Kulikov, Victor Alexeevich, Maria Sergeevna Andreeva, Alexander Vasil’evich Koryabin et Victor Ivanovich Shmalhausen. « Method of estimation of turbulence characteristic scales ». Applied Optics 51, n^o 36 (12 décembre 2012) : 8505. http://dx.doi.org/10.1364/ao.51.008505.

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Madan, D. B., et E. Seneta. « Chebyshev Polynomial Approximations and Characteristic Function Estimation ». Journal of the Royal Statistical Society : Series B (Methodological) 49, n^o 2 (janvier 1987) : 163–69. http://dx.doi.org/10.1111/j.2517-6161.1987.tb01687.x.

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Tomida, Motomasa, et Kiyoshi Hoshino. « Wearable Device for High-Speed Hand Pose Estimation with a Ultrasmall Camera ». Journal of Robotics and Mechatronics 27, n^o 2 (20 avril 2015) : 167–73. http://dx.doi.org/10.20965/jrm.2015.p0167.

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<div class=""abs_img""> <img src=""[disp_template_path]/JRM/abst-image/00270002/06.jpg"" width=""300"" /> Hand pose estimation with ultrasmall camera</div> Operating a robot intentionally by using various complex motions of the hands and fingers requires a system that accurately detects hand and finger motions at high speed. This study uses an ultrasmall camera and compact computer for development of a wearable device of hand pose estimation, also called a hand-capture device. The accurate estimations, however, require data matching with a large database. But a compact computer usually has only limited memory and low machine power. We avoided this problem by reducing frequently used image characteristics from 1,600 dimensions to 64 dimensions of characteristic quantities. This saved on memory and lowered computational cost while achieving high accuracy and speed. To enable an operator to wear the device comfortably, the camera was placed as close to the back of the hand as possible to enable hand pose estimation from hand images without fingertips. A prototype device with a compact computer used to evaluate performance indicated that the device achieved high-speed estimation. Estimation accuracy was 2.32°±14.61° at the PIP joint of the index finger and 3.06°±10.56° at the CM joint of the thumb – as accurate as obtained using previous methods. This indicated that dimensional compression of image-characteristic quantities is important for realizing a compact hand-capture device. </span>

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Ronold, Knut O., et Andreas T. Echtermeyer. « Using Tolerance Bounds for Estimation of Characteristic Fatigue Curves for Composites with Confidence ». Safety 8, n^o 1 (23 décembre 2021) : 1. http://dx.doi.org/10.3390/safety8010001.

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Fatigue S–N curves provide the number of stress cycles that result in fatigue failure at stress range S and need to be measured for new engineering materials where data are not as readily available as they are for well-characterized and widely used metals. A simple statistical method for the estimation of characteristic fatigue curves defined in terms of lower-tail quantiles in probability distributions of dependent variables is presented. The method allows for the estimation of such quantiles with a specified confidence level, taking account of the statistical uncertainty caused by a limited number of experimental test results available for the estimation. The traditional general approach for estimating characteristic S–N curves by tolerance bounds is complicated and is not much used by engineers. The presented approach allows for calculating the curves with a simple spreadsheet. The only requirement is that the experimental log S data for the S–N curve are fairly uniformly distributed over a finite logS interval, where S denotes the stress range. Experimental fatigue test programs are often designed such that test data fulfil this assumption. Although developed with fatigue of composite laminates in mind, the presented statistical procedure and the presented associated charts are valid for fatigue curve estimation for any material.

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Roy, Soumya, Biswabrata Pradhan et E. V. Gijo. « Estimation of P(X ». International Journal of Quality & ; Reliability Management 34, n^o 7 (7 août 2017) : 1111–22. http://dx.doi.org/10.1108/ijqrm-05-2016-0070.

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Purpose The purpose of this paper is to compare various methods of estimation of P(X<Y) based on Type-II censored data, where X and Y represent a quality characteristic of interest for two groups. Design/methodology/approach This paper assumes that both X and Y are independently distributed generalized half logistic random variables. The maximum likelihood estimator and the uniformly minimum variance unbiased estimator of R are obtained based on Type-II censored data. An exact 95 percent maximum likelihood estimate-based confidence interval for R is also provided. Next, various Bayesian point and interval estimators are obtained using both the subjective and non-informative priors. A real life data set is analyzed for illustration. Findings The performance of various point and interval estimators is judged through a detailed simulation study. The finite sample properties of the estimators are found to be satisfactory. It is observed that the posterior mean marginally outperform other estimators with respect to the mean squared error even under the non-informative prior. Originality/value The proposed methodology can be used for comparing two groups with respect to a suitable quality characteristic of interest. It can also be applied for estimation of the stress-strength reliability, which is of particular interest to the reliability engineers.

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Gao, Lei Lei, et Xin Tao Xia. « Poor Information Analysis of Rolling Bearing Friction Torque Characteristic Parameter Based on Phase Space ». Advanced Materials Research 382 (novembre 2011) : 167–71. http://dx.doi.org/10.4028/www.scientific.net/amr.382.167.

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The friction torque of rolling bearings belongs to an information poor system with unknown probability distributions and trends. This counteracts dynamical assessment for the characteristics of the rolling bearing friction torque as a time series. For this reason, the chaos theory is employed to recover the original dynamic characteristics of a friction torque time series by means of the phase space reconstruction theory. The dynamical Bayesian probability density function of the characteristic parameters of the friction torque is constructed by the information poor theory based on the phase space. The method for point estimation, interval estimation, and trend estimation of the characteristic parameters is proposed in this paper. The investigation shows that the error between the calculated result and the experimental result is very small.

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Fu, Hongyu, Chufeng Wang, Guoxian Cui, Wei She et Liang Zhao. « Ramie Yield Estimation Based on UAV RGB Images ». Sensors 21, n^o 2 (19 janvier 2021) : 669. http://dx.doi.org/10.3390/s21020669.

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Timely and accurate crop growth monitoring and yield estimation are important for field management. The traditional sampling method used for estimation of ramie yield is destructive. Thus, this study proposed a new method for estimating ramie yield based on field phenotypic data obtained from unmanned aerial vehicle (UAV) images. A UAV platform carrying RGB cameras was employed to collect ramie canopy images during the whole growth period. The vegetation indices (VIs), plant number, and plant height were extracted from UAV-based images, and then, these data were incorporated to establish yield estimation model. Among all of the UAV-based image data, we found that the structure features (plant number and plant height) could better reflect the ramie yield than the spectral features, and in structure features, the plant number was found to be the most useful index to monitor the yield, with a correlation coefficient of 0.6. By fusing multiple characteristic parameters, the yield estimation model based on the multiple linear regression was obviously more accurate than the stepwise linear regression model, with a determination coefficient of 0.66 and a relative root mean square error of 1.592 kg. Our study reveals that it is feasible to monitor crop growth based on UAV images and that the fusion of phenotypic data can improve the accuracy of yield estimations.

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Brobbey, Anita, Aerambamoorthy Thavaneswaran et Saumen Mandal. « Wrapped Zero-inflated Poisson Distribution and Its Properties ». International Journal of Statistics and Probability 5, n^o 1 (24 décembre 2015) : 111. http://dx.doi.org/10.5539/ijsp.v5n1p111.

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Recently, there has been a growing interest in discrete valued wrapped distributions and the trigonometric moments.<br />Characteristic functions of stable processes have been used to study the estimation of the model parameters using<br />estimating function approach (Thavaneswaran et al., 2013). In this paper, we introduce a new discrete circular distribution,<br />the wrapped zero-inflated Poisson distribution and derive its population characteristics.<br /><br />

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Fredlund, Delwyn G. « The 1999 R.M. Hardy Lecture : The implementation of unsaturated soil mechanics into geotechnical engineering ». Canadian Geotechnical Journal 37, n^o 5 (1 octobre 2000) : 963–86. http://dx.doi.org/10.1139/t00-026.

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The implementation of unsaturated soil mechanics into geotechnical engineering practice requires that there be a paradigm shift from classical soil mechanics methodology. The primary drawback to implementation has been the excessive costs required to experimentally measure unsaturated soil properties. The use of the soil-water characteristic curve has been shown to be the key to the implementation of unsaturated soil mechanics. Numerous techniques have been proposed and studied for the assessment of the soil-water characteristic curves. These techniques range from direct laboratory measurement to indirect estimation from grain-size curves and knowledge-based database systems. The soil-water characteristic curve can then be used for the estimation of unsaturated soil property functions. Theoretically based techniques have been proposed for the estimation of soil property functions such as (i) coefficient of permeability, (ii) water storage modulus, and (iii) shear strength. Gradually these estimations are producing acceptable procedures for geotechnical engineering practices for unsaturated soils. The moisture flux ground surface boundary condition is likewise becoming a part of the solution of most problems involving unsaturated soils. The implementation process for unsaturated soils will still require years of collaboration between researchers and practicing geotechnical engineers.Key words: unsaturated soil mechanics, soil suction, unsaturated soil property functions, negative pore-water pressure, matric suction, soil-water characteristic curve.

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Zhou, Peng, Xiao Tai Niu, Song Guo et Ming Deng Shi. « Research Jujube Pest Stress Index Leaf Pigment Hyperspectral Model Based on Wireless Sensor Networks in the Southern Region of Xinjiang ». Advanced Materials Research 955-959 (juin 2014) : 763–70. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.763.

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Measured southern jujube pest stress index leaf pigment, create jujube jujube leaf rust sensitive bands characteristic parameter table, analyze the spectral characteristics of the relevant characteristics and vegetation index jujube high correlation parameters. Determination of diseased leaves and growing spectrum of different pigment content. Analysis jujube leaf rust pigment content and spectral reflectance correlation study comparing jujube leaf rust pigment content and differential spectral correlation. Hyperspectral characteristic parameters to achieve the southern jujube jujube leaf rust pigments PC1/PC2 and PC1+PC2 content estimation. Using a combination of linear and polynomial fitting method to construct the canopy hyperspectral disease dates Brix content estimation model and test. The probabilistic neural network PNN and SVM classifier SVC applied to hyperspectral estimation model, comparative analysis of model accuracy. The results of the quantitative estimation of disease hyperspectral information dates pigment content in leaves of jujube growing use of high spectral monitoring and impact assessment of disease have high practical value. classification accuracy of 98%, obtained very satisfactory recognition results.

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Zhang, Bo, Xuejian Li, Huaqiang Du, Guomo Zhou, Fangjie Mao, Zihao Huang, Lv Zhou, Jie Xuan, Yulin Gong et Chao Chen. « Estimation of Urban Forest Characteristic Parameters Using UAV-Lidar Coupled with Canopy Volume ». Remote Sensing 14, n^o 24 (16 décembre 2022) : 6375. http://dx.doi.org/10.3390/rs14246375.

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The estimation of characteristic parameters such as diameter at breast height (DBH), aboveground biomass (AGB) and stem volume (V) is an important part of urban forest resource monitoring and the most direct manifestation of the ecosystem functions of forests; therefore, the accurate estimation of urban forest characteristic parameters is valuable for evaluating urban ecological functions. In this study, the height and density characteristic variables of canopy point clouds were extracted as Scheme 1 and combined with the canopy structure variables as Scheme 2 based on unmanned aerial vehicle lidar (UAV-Lidar). We analyzed the spatial distribution characteristics of the canopies of different tree species, and multiple linear regression (MLR), support vector regression (SVR), and random forest (RF) models were used to estimate the DBH, AGB, and V of urban single trees. The estimation accuracy of different models was evaluated based on the field-measured data. The results indicated that the model accuracy of coupling canopy structure variables (R2 = 0.69–0.85, rRMSE = 9.87–24.67%) was higher than that of using only point-cloud-based height and density characteristic variables. The comparison of the results of different models shows that the RF model had the highest estimation accuracy (R2 = 0.76–0.85, rRMSE = 9.87–22.51%), which was better than that of the SVR and MLR models. In the RF model, the estimation accuracy of AGB was the highest (R2 = 0.85, rRMSE = 22.51%), followed by V, with an accuracy of R2 = 0.83, rRMSE = 18.51%, and the accuracy of DBH was the lowest (R2 = 0.76, rRMSE = 9.87%). The results of the study provide an important reference for the estimation of single-tree characteristic parameters in urban forests based on UAV-Lidar.

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Wu, Yang Bo, Jian Ping Hu et Hong Li. « Leakage Power Estimation of Adiabatic Circuits Using SPICE in Nanometer CMOS Processes ». Advanced Materials Research 108-111 (mai 2010) : 625–30. http://dx.doi.org/10.4028/www.scientific.net/amr.108-111.625.

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In deep sub-micro CMOS process, the leakage power is becoming a significant proportion in power dissipation. Hence, estimating the leakage power of CMOS circuits is very important in low-power design. In this paper, an estimation technology for the total leakage power of adiabatic logic circuits by using SPICE is proposed. The basic principle of power estimation for traditional CMOS circuits using SPICE is introduced. According to the energy dissipation characteristic of adiabatic circuits, the estimation technology for leakage power is discussed. Taken as an example, the estimation for total leakage power dissipations of PAL-2N (pass-transistor adiabatic logic with NMOS pull-down configuration) circuits is illustrated using the proposed estimation technology.

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Li, Yunxia, et Lei Li. « Parameter Estimation of a Countershaft Brake for Heavy-Duty Vehicles with Automated Mechanical Transmission ». Processes 9, n^o 6 (13 juin 2021) : 1036. http://dx.doi.org/10.3390/pr9061036.

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A countershaft brake is used as a transmission brake (TB) to realize synchronous shifting by reducing the automated mechanical transmission (AMT) input shaft’s speed rapidly. This process is performed to reduce shifting time and improve shifting quality for heavy-duty vehicles equipped with AMT without synchronizer. To improve controlled synchronous shifting, the AMT input shaft’s equivalent resistance torque and the TB’s characteristic parameters are studied. An AMT dynamic model under neutral gear position is analyzed during the synchronous control interval. A dynamic model of the countershaft brake is discussed, and its control flow is given. The parameter identification method of the AMT input shaft’s equivalent resistance torque is given on the basis of the least squares algorithm. The parameter identification of the TB’s characteristic parameters is proposed on the basis of the recursive least squares method (RLSM). Experimental results show that the recursive estimations of the TB’s characteristic parameters under different duty cycles of the TB solenoid valve, including brake torque estimation, estimation accuracy, and braking intensity estimation, can be effectively estimated. The research provides some reliable evidence to further study the synchronous shifting control schedule for heavy-duty vehicles with AMT.

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MATSUNAGA, Nobuhiro, Kosei TAKEHARA et Yoichi AWAYA. « Estimation of characteristic quantities of offshore vortex train. » Doboku Gakkai Ronbunshu, n^o 417 (1990) : 157–64. http://dx.doi.org/10.2208/jscej.1990.417_157.

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Christoforo, André L., Andrea de S. Almeida, Tamiris L. S. Lanini, Rodrigo de S. Nogueira et Francisco A. R. Lahr. « ESTIMATION OF THE CHARACTERISTIC VALUE OF WOOD STRENGTH ». Engenharia Agrícola 39, n^o 1 (février 2019) : 127–32. http://dx.doi.org/10.1590/1809-4430-eng.agric.v39n1p127-132/2019.

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Chaudhury, Kaustav, Chandranath Banerjee et Swapnil Urankar. « Estimation of characteristic vortex structures in complex flow ». Journal of Turbulence 22, n^o 9 (28 mai 2021) : 517–34. http://dx.doi.org/10.1080/14685248.2021.1932939.

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Leong, Eng-Choon. « Soil-water characteristic curves - Determination, estimation and application ». Japanese Geotechnical Society Special Publication 7, n^o 2 (30 avril 2019) : 21–30. http://dx.doi.org/10.3208/jgssp.v07.003.

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焦, 义民. « Sparsity Estimation Method Based on Noise Characteristic Analysis ». Journal of Image and Signal Processing 05, n^o 02 (2016) : 73–79. http://dx.doi.org/10.12677/jisp.2016.52010.

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Yanushkevichiene, Olga, et Viacheslav Saenko. « Estimation of the characteristic exponent of stable laws ». Lithuanian Mathematical Journal 57, n^o 2 (avril 2017) : 266–81. http://dx.doi.org/10.1007/s10986-017-9360-5.

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KIKUYA, Yuhei, et Saburo MATUNAGA. « Relative Attitude Detection Using Characteristic Points Position Estimation ». Proceedings of the Space Engineering Conference 2018.28 (2018) : 1A4. http://dx.doi.org/10.1299/jsmesec.2018.28.1a4.

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Pepe, Margaret S., Gary Longton et Holly Janes. « Estimation and Comparison of Receiver Operating Characteristic Curves ». Stata Journal : Promoting communications on statistics and Stata 9, n^o 1 (mars 2009) : 1–16. http://dx.doi.org/10.1177/1536867x0900900101.

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del Pozo, C. F., M. J. Kosch et F. Honary. « Estimation of the characteristic energy of electron precipitation ». Annales Geophysicae 20, n^o 9 (30 septembre 2002) : 1349–59. http://dx.doi.org/10.5194/angeo-20-1349-2002.

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Abstract. Data from simultaneous observations (on 13 February 1996, 9 November 1998, and 12 February 1999) with the IRIS, DASI and EISCAT systems are employed in the study of the energy distribution of the electron precipitation during substorm activity. The estimation of the characteristic energy of the electron precipitation over the common field of view of IRIS and DASI is discussed. In particular, we look closely at the physical basis of the correspondence between the characteristic energy, the flux-averaged energy, as defined below, and the logarithm of the ratio of the green-light intensity to the square of absorption. This study expands and corrects results presented in the paper by Kosch et al. (2001). It is noticed, moreover, that acceleration associated with diffusion processes in the magnetosphere long before precipitation may be controlling the shape of the energy spectrum. We propose and test a "mixed" distribution for the energy-flux spectrum, exponential at the lower energies and Maxwellian or modified power-law at the higher energies, with a threshold energy separating these two regimes. The energy-flux spectrum at Tromsø, in the 1–320 keV range, is derived from EISCAT electron density profiles in the 70–140 km altitude range and is applied in the "calibration" of the optical intensity and absorption distributions, in order to extrapolate the flux and characteristic energy maps.Key words. Ionosphere (auroral ionosphere; particle precipitation; particle acceleration)

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SONG, Xin, Youwei ZHANG et Zijun LIU. « Radiation Characteristic Estimation of Chang'E-3 Landing Area ». Chinese Journal of Space Science 36, n^o 6 (2016) : 916. http://dx.doi.org/10.11728/cjss2016.06.916.

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Clarkson, Eric. « Estimation receiver operating characteristic curve and ideal observers for combined detection/estimation tasks ». Journal of the Optical Society of America A 24, n^o 12 (1 octobre 2007) : B91. http://dx.doi.org/10.1364/josaa.24.000b91.

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Bocharnikov, Victor, Sergey Sveshnikov et Radion Timoshenko. « Estimating the outcome of an active phase in the military conflict on Eastern Ukraine based on the Sugeno fuzzy integral ». Yugoslav Journal of Operations Research, n^o 00 (2020) : 42. http://dx.doi.org/10.2298/yjor200918042b.

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A military conflict (especially its active phase) is a time of maximum exertion of all the powers of the state and society, a time that requires quick and correct decisions from state bodies. The quality of these decisions is largely determined by the estimation adequacy of the current situation. As the analysis shows, modern military conflicts start suddenly and develop rapidly. The official informing system turns out to be ineffective, what leads to numerous mistakes in decision-making. In addition, modern military conflicts are of a hybrid nature. The outcome of such military conflicts depends on many factors of a non-military nature, for example, the quality of governance, sup- port from the population, international assistance. These factors are often formulated qualitatively (linguistically), and the conditions of the active phase of a military conflict do not give time to check the adequacy of quantitative data. Therefore, it is necessary that the method for estimating the outcome of the active phase takes into account the data uncertainty and ensures a generalization of the partial characteristics of the current situation. Based on the analysis of known approaches to the description and process- ing of uncertainty, the authors proposed using the methods of fuzzy integral calculus to describe partial characteristics and calculate a generalized characteristic, which is an estimation of the success of the outcome of an active phase. The authors have solved the following subproblems: identification of structure and parameters of standard for estimating; choice of the observation channel of the characteristics of the current situation; constructing the algorithm for estimations generalization. The authors demonstrated the work of the proposed algorithm by the example of estimating the results of hostilities in eastern Ukraine in July 2014.

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Klockiewicz, Z., et G. Ślaski. « The estimation of frequency response of nonlinear quarter car model and bilinear model of damper characteristics ». IOP Conference Series : Materials Science and Engineering 1247, n^o 1 (1 juillet 2022) : 012007. http://dx.doi.org/10.1088/1757-899x/1247/1/012007.

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Abstract The paper presents proposed and tested methods of estimation of frequency response of nonlinear quarter car suspension model and comparison with method for linear model used for research of vehicle vertical dynamics. Linear quarter car suspension model is widely used for estimation of comfort and safety performance of passive and semiactive suspensions. The real suspension - especially shock absorbers - are non-linear in three aspects: static characteristics, hysteresis and the presence of friction. Testing linear suspension model is possible with the use of analytical transfer function formulas but testing real suspension on a testing stand or even virtual but nonlinear suspension needs to use methods of transfer function estimation. It was necessary to design appropriate input signal allowing to get useful response signals. With the use of obtained frequency responses a method of linear estimation of nonlinear suspension for a given range of working condition was proposed. Also the bilinear model of damper characteristic estimation was proposed and tested proving to be good alternative to nonlinear characteristic.

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