Bibliographies thématiques / Empirical calibration / Articles de revues

Articles de revues sur le sujet « Empirical calibration »

Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Empirical calibration.
Auteur : Grafiati
Publié le 10 mars 2023
Mis à jour le 11 mars 2023

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres

Choisissez une source :

Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Empirical calibration ».

À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.

Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.

Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.

1

Millward, Christopher G., et Gordon A. H. Walker. « An Empirical Hγ - Luminosity Calibration ». Symposium - International Astronomical Union 111 (1985) : 377–80. http://dx.doi.org/10.1017/s0074180900079006.

Texte intégral
Résumé :
High signal-to-noise Reticon spectra for 87 members of 8 open clusters and associations together with 37 stars having reliable parallaxes (early A-type stars with reliable trigonometric parallaxes, eclipsing binaries, and visual binaries) have been used to calibrate the W(Hγ)-Mv relation for spectral types 0 to early A of luminosity classes III-V. The new calibration has a mean probable dispersion of ±0.28 mag. The distance modulus of the Pleiades is 5.54 ± 0.06 mag, which is in excellent agreement with other, recent determinations, as are the distance moduli for all the calibrating clusters. The use of visual-binary parallaxes implies a Hyades distance modulus of about 3.0 which is significantly smaller than the Hanson (1980) value of 3.30 mag. Although no spectral-type corrections are necessary, stellar evolution probably affects the construction of the new calibration and special care should be taken when determining distance moduli from slightly evolved cluster sequences or for individual stars. Systematic departures from the calibration may be present for stars with Vsin i ≥ 220–250 km/sec. Significant residuals are found between our values of W(Hγ) and those of Petrie in the range 1–13 Å equivalent width, which are due in part to systematic errors in Petrie's W(Hγ) measures. Our distance modulus of 11.11 mag for NGC 2244 is in excellent agreement with the photometric distance. The new calibration is compared to other early type star calibrations for main sequence stars. It is 1.2 mag brighter than Petrie's (1965) Hγ calibration at spectral type 06 and 0.7 mag brighter at A3. For types B1 and earlier the new calibration averages 0.4 mag brighter than the Balona and Crampton (1974) Hγ calibration. There is generally good agreement with the Blaauw (1963) MK calibration although the latter is 0.4 mag brighter at spectral type BO. The Crawford (1978) Hβ calibration is up to 0.5 mag brighter for the earlier spectral types and 0.4 mag fainter for later types. More complete discussions of the Hγ-luminosity calibration are available in Millward and Walker (1984, 1985).
Styles APA, Harvard, Vancouver, ISO, etc.
2

Dawid, A. P. « Calibration-Based Empirical Probability ». Annals of Statistics 13, no 4 (décembre 1985) : 1251–74. http://dx.doi.org/10.1214/aos/1176349736.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
3

Berardi, Michele, et Jaqueson K. Galimberti. « Empirical calibration of adaptive learning ». Journal of Economic Behavior & ; Organization 144 (décembre 2017) : 219–37. http://dx.doi.org/10.1016/j.jebo.2017.10.004.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
4

Hansen, Lars Peter, et James J. Heckman. « The Empirical Foundations of Calibration ». Journal of Economic Perspectives 10, no 1 (1 février 1996) : 87–104. http://dx.doi.org/10.1257/jep.10.1.87.

Texte intégral
Résumé :
Interest in simulating recently developed dynamic stochastic general equilibrium models of the economy stimulated a demand for parameters. This has given rise to calibration as advocated by Finn E. Kydland and Edward C. Prescott (1982). This paper explores the implicit assumptions underlying their calibration method. The authors question that there is a ready supply of micro estimates available to calibrate macroeconomic models. Measures of parameter uncertainty and specification sensitivity should be routinely reported. They propose a more symbiotic role for calibration as providing signals to microeconomists about important gaps in knowledge, which when filled will solidify the empirical underpinning, improving the credibility of the quantitative output.
Styles APA, Harvard, Vancouver, ISO, etc.
5

Schervish, Mark J. « Discussion : Calibration-Based Empirical Probability ». Annals of Statistics 13, no 4 (décembre 1985) : 1274–82. http://dx.doi.org/10.1214/aos/1176349737.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
6

Dawid, A. P. « Rejoinder : Calibration-Based Empirical Probability ». Annals of Statistics 13, no 4 (décembre 1985) : 1282–85. http://dx.doi.org/10.1214/aos/1176349738.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
7

Raut, Bipin, Morakot Kaewmanee, Amit Angal, Xiaoxiong Xiong et Dennis Helder. « Empirical Absolute Calibration Model for Multiple Pseudo-Invariant Calibration Sites ». Remote Sensing 11, no 9 (9 mai 2019) : 1105. http://dx.doi.org/10.3390/rs11091105.

Texte intégral
Résumé :
This work extends an empirical absolute calibration model initially developed for the Libya 4 Pseudo-Invariant Calibration Site (PICS) to five additional Saharan Desert PICS (Egypt 1, Libya 1, Niger 1, Niger 2, and Sudan 1), and demonstrates the efficacy of the resulting models at predicting sensor top-of-atmosphere (TOA) reflectance. It attempts to generate absolute calibration models for these PICS that have an accuracy and precision comparable to or better than the current Libya 4 model, with the intent of providing additional opportunities for sensor calibration. In addition, this work attempts to validate the general applicability of the model to other sites. The method uses Terra Moderate Resolution Imaging Spectroradiometer (MODIS) as the reference radiometer and Earth Observing-1 (EO-1) Hyperion image data to provide a representative hyperspectral reflectance profile of the PICS. Data from a region of interest (ROI) in an “optimal region” of 3% temporal, spatial, and spectral stability within the PICS are used for developing the model. The developed models were used to simulate observations of the Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+), Landsat 8 (L8) Operational Land Imager (OLI), Sentinel 2A (S2A) MultiSpectral Instrument (MSI) and Sentinel 2B (S2B) MultiSpectral Instrument (MSI) from their respective launch date through 2018. The models developed for the Egypt 1, Libya 1 and Sudan 1 PICS have an estimated accuracy of approximately 3% and precision of approximately 2% for the sensors used in the study, comparable to the current Libya 4 model. The models developed for the Niger 1 and Niger 2 sites are significantly less accurate with similar precision.
Styles APA, Harvard, Vancouver, ISO, etc.
8

Chrysanthopoulou, Stavroula A., Carolyn M. Rutter et Constantine A. Gatsonis. « Bayesian versus Empirical Calibration of Microsimulation Models : A Comparative Analysis ». Medical Decision Making 41, no 6 (8 mai 2021) : 714–26. http://dx.doi.org/10.1177/0272989x211009161.

Texte intégral
Résumé :
Calibration of a microsimulation model (MSM) is a challenging but crucial step for the development of a valid model. Numerous calibration methods for MSMs have been suggested in the literature, most of which are usually adjusted to the specific needs of the model and based on subjective criteria for the selection of optimal parameter values. This article compares 2 general approaches for calibrating MSMs used in medical decision making, a Bayesian and an empirical approach. We use as a tool the MIcrosimulation Lung Cancer (MILC) model, a streamlined, continuous-time, dynamic MSM that describes the natural history of lung cancer and predicts individual trajectories accounting for age, sex, and smoking habits. We apply both methods to calibrate MILC to observed lung cancer incidence rates from the Surveillance, Epidemiology and End Results (SEER) database. We compare the results from the 2 methods in terms of the resulting parameter distributions, model predictions, and efficiency. Although the empirical method proves more practical, producing similar results with smaller computational effort, the Bayesian method resulted in a calibrated model that produced more accurate outputs for rare events and is based on a well-defined theoretical framework for the evaluation and interpretation of the calibration outcomes. A combination of the 2 approaches is an alternative worth considering for calibrating complex predictive models, such as microsimulation models.
Styles APA, Harvard, Vancouver, ISO, etc.
9

Piedehierro, A. A., M. L. Cancillo, J. M. Vilaplana et A. Serrano. « Long-Term Global Irradiance Calibration of Multifilter UV Radiometers ». Journal of Atmospheric and Oceanic Technology 36, no 12 (décembre 2019) : 2415–27. http://dx.doi.org/10.1175/jtech-d-18-0132.1.

Texte intégral
Résumé :
AbstractMultifilter instruments such as the Norwegian Institute for Air Research (NILU)-UV Irradiance Meter (NILU-UV) are suitable for long-term monitoring of UV radiation, as long as their irradiance scale is maintained. The sensitivity of these instruments varies with time; thus, periodic standard absolute calibrations are required. However, standard calibrations may be insufficient to characterize the short-term variations of channels sensitivity. Therefore, results from standard calibrations have to be combined with the information derived from frequent relative calibrations, leading to a stable irradiance scale. This paper focuses on the long-term application of three calibration methods, hereinafter referred to as CC, CC2, and CC2(ϕ), as applied to the NILU-UV 119 multifilter radiometer. Here a generalization is proposed, consisting of using empirical functions in order to guarantee the accurate calibration of multifilter instruments over long time periods. These function-based methods need to be updated regularly to account for changes on instrument sensitivity. The changes in sensitivity of the NILU-UV 119 were found to be channel dependent. The detected drifts range from 23% to 42% for a 4-yr period of study. Time series of calibrated irradiance are obtained by applying the proposed methods. Results suggest that calibration methods using empirical functions perform better than classic calibration approaches that use constant calibration factors. When methods CC2 and CC2(ϕ) are applied, calibrated irradiances agree with the measurements of reference within ±5% for channel 305 and within ±3% for channels 312, 320, and 340.
Styles APA, Harvard, Vancouver, ISO, etc.
10

George, EdwardI. « Calibration and empirical Bayes variable selection ». Biometrika 87, no 4 (1 décembre 2000) : 731–47. http://dx.doi.org/10.1093/biomet/87.4.731.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
11

Lei, Yuanxin, Huifen Liu et Zhixiong Lu. « Comparisons of Two Approaches for Geotechnical Model Calibration with Scarce Data ». Advances in Civil Engineering 2021 (10 décembre 2021) : 1–12. http://dx.doi.org/10.1155/2021/4245051.

Texte intégral
Résumé :
Geotechnical models are usually built upon assumptions and simplifications, inevitably resulting in discrepancies between model predictions and measurements. To enhance prediction accuracy, geotechnical models are typically calibrated against measurements by bringing in additional empirical or semiempirical correction terms. Different approaches have been used in the literature to determine the optimal values of empirical parameters in the correction terms. When measured data are abundant, calibration outcomes using different approaches can be expected to be practically the same. However, if measurements are scarce or limited, calibration outcomes could differ significantly, depending largely on the adopted calibration approach. In this study, we examine two most commonly used approaches for geotechnical model calibration in the literature, namely, (1) purely data-catering (PDC) approach, and (2) root mean squared error (RMSE) method. Here, the purely data-catering approach refers to selection of empirical parameter values that minimize coefficient of variation of model factor while maintains its mean value of one, based solely on measured data. A real case of calibrating the Federal Highway Administration (FHWA) simplified facing load model for design of soil nail walls is illustrated to thoroughly elaborate the differences in practical calibration and design outcomes using the two approaches under scarce data conditions.
Styles APA, Harvard, Vancouver, ISO, etc.
12

Fayers, F. J., M. J. Blunt et M. A. Christie. « Accurate Calibration of Empirical Viscous Fingering Models ». Revue de l'Institut Français du Pétrole 46, no 3 (mai 1991) : 311–24. http://dx.doi.org/10.2516/ogst:1991015.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
13

Kamzolkin, V. A., S. D. Ivanov et A. N. Konilov. « Empirical phengite geobarometer : Background, calibration, and application ». Geology of Ore Deposits 58, no 8 (décembre 2016) : 613–22. http://dx.doi.org/10.1134/s1075701516080092.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
14

Gorgas, J., N. Cardiel, S. Pedraz et J. J. González. « Empirical calibration of the λ4000 Å break ». Astronomy and Astrophysics Supplement Series 139, no 1 (octobre 1999) : 29–41. http://dx.doi.org/10.1051/aas:1999375.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
15

Min, Soh Ling, Josef Kittler et Jiri Matas. « Empirical evaluation of a calibration chart detector ». Machine Vision and Applications 12, no 6 (1 juin 2001) : 305–25. http://dx.doi.org/10.1007/s001380050148.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
16

Chaity, Manisha Das, Morakot Kaewmanee, Larry Leigh et Cibele Teixeira Pinto. « Hyperspectral Empirical Absolute Calibration Model Using Libya 4 Pseudo Invariant Calibration Site ». Remote Sensing 13, no 8 (15 avril 2021) : 1538. http://dx.doi.org/10.3390/rs13081538.

Texte intégral
Résumé :
The objective of this paper is to find an empirical hyperspectral absolute calibration model using Libya 4 pseudo invariant calibration site (PICS). The approach involves using the Landsat 8 (L8) Operational Land Imager (OLI) as the reference radiometer and using Earth Observing One (EO-1) Hyperion, with a spectral resolution of 10 nm as a hyperspectral source. This model utilizes data from a region of interest (ROI) in an “optimal region” of 3% temporal, spatial, and spectral stability within the Libya 4 PICS. It uses an improved, simple, empirical, hyperspectral Bidirectional Reflectance Distribution function (BRDF) model accounting for four angles: solar zenith and azimuth, and view zenith and azimuth angles. This model can perform absolute calibration in 1 nm spectral resolution by predicting TOA reflectance in all existing spectral bands of the sensors. The resultant model was validated with image data acquired from satellite sensors such as Landsat 7, Sentinel 2A, and Sentinel 2B, Terra MODIS, Aqua MODIS, from their launch date to 2020. These satellite sensors differ in terms of the width of their spectral bandpass, overpass time, off-nadir viewing capabilities, spatial resolution, and temporal revisit time, etc. The result demonstrates the efficacy of the proposed model has an accuracy of the order of 3% with a precision of about 3% for the nadir viewing sensors (with view zenith angle up to 5°) used in the study. For the off-nadir viewing satellites with view zenith angle up to 20°, it can have an estimated accuracy of 6% and precision of 4%.
Styles APA, Harvard, Vancouver, ISO, etc.
17

Mackinson, Steven. « Combined analyses reveal environmentally driven changes in the North Sea ecosystem and raise questions regarding what makes an ecosystem model’s performance credible ? » Canadian Journal of Fisheries and Aquatic Sciences 71, no 1 (janvier 2014) : 31–46. http://dx.doi.org/10.1139/cjfas-2013-0173.

Texte intégral
Résumé :
When an ecosystem model of the North Sea is calibrated to data from multiple trophic levels, the model estimated the primary production required to support the food web correlates temporally with observed changes in sea temperature and nutrient levels, supporting evidence from empirical analyses. However, a different result is given from an alternative calibration using fish stock data only. The inference taken from the emergent primary production – temperature relationship and empirical data are that, on balance, there is stronger overall evidence to support the calibration constrained at multiple trophic levels. Two important implications of the findings are (i) that the relative importance of fishing and environmental effects is likely to be interpreted differently depending on the calibration approach and (ii) the contrasting model calibrations would give different responses to fishing policies. It raises questions regarding how to judge the performance (and credibility) of an ecosystem model and the critical importance of conducting empirical and modelling analyses in parallel. Adopting a combined approach to ecosystem modelling is an important step in the pursuit of operational and defensible tools to support the ecosystem approach to management.
Styles APA, Harvard, Vancouver, ISO, etc.
18

Marino, R. A., F. F. Rosales-Ortega, F. Sánchez et A. Gil de Paz. « New empirical metallicity calibrations : Joint analysis of CALIFA data and literature Te-based measurements ». Proceedings of the International Astronomical Union 10, S309 (juillet 2014) : 328. http://dx.doi.org/10.1017/s1743921314010229.

Texte intégral
Résumé :
AbstractIn Marino et al. (2013) we provide revisited empirical calibrations for the oxygen abundances in HII regions based on the O3N2 and N2 indicators. This work is based on the most comprehensive compilation of both Te-based and multiple strong-line (ONS-based) ionized-gas abundance measurements in external galaxies to date in terms of all statistical significance, quality, and coverage of the parameters space. Our dataset compiles the Te-based abundances of 603 HII regions extracted from the literature but also includes new measurements from the CALIFA survey. We also present a comparison between our revisited calibrations with a total of 3423 additional CALIFA HII complexes with abundances derived using the ONS calibration. The O3N2 and N2 indicators can be empirically applied to derive oxygen abundances calibrations from either direct-abundance determinations with random errors of 0.18 and 0.16, respectively, and they show shallower abundance dependencies and statistically significant offsets compared to the classical calibrations (as the one of Pettini & Pagel (2004)).
Styles APA, Harvard, Vancouver, ISO, etc.
19

Schepen, Andrew, Yvette Everingham et Quan J. Wang. « On the Joint Calibration of Multivariate Seasonal Climate Forecasts from GCMs ». Monthly Weather Review 148, no 1 (1 janvier 2020) : 437–56. http://dx.doi.org/10.1175/mwr-d-19-0046.1.

Texte intégral
Résumé :
Abstract Multivariate seasonal climate forecasts are increasingly required for quantitative modeling in support of natural resources management and agriculture. GCM forecasts typically require postprocessing to reduce biases and improve reliability; however, current seasonal postprocessing methods often ignore multivariate dependence. In low-dimensional settings, fully parametric methods may sufficiently model intervariable covariance. On the other hand, empirical ensemble reordering techniques can inject desired multivariate dependence in ensembles from template data after univariate postprocessing. To investigate the best approach for seasonal forecasting, this study develops and tests several strategies for calibrating seasonal GCM forecasts of rainfall, minimum temperature, and maximum temperature with intervariable dependence: 1) simultaneous calibration of multiple climate variables using the Bayesian joint probability modeling approach; 2) univariate BJP calibration coupled with an ensemble reordering method (the Schaake shuffle); and 3) transformation-based quantile mapping, which borrows intervariable dependence from the raw forecasts. Applied to Australian seasonal forecasts from the ECMWF System4 model, univariate calibration paired with empirical ensemble reordering performs best in terms of univariate and multivariate forecast verification metrics, including the energy and variogram scores. However, the performance of empirical ensemble reordering using the Schaake shuffle is influenced by the selection of historical data in constructing a dependence template. Direct multivariate calibration is the second-best method, with its far superior performance in in-sample testing vanishing in cross validation, likely because of insufficient data relative to the number of parameters. The continued development of multivariate forecast calibration methods will support the uptake of seasonal climate forecasts in complex application domains such as agriculture and hydrology.
Styles APA, Harvard, Vancouver, ISO, etc.
20

Daly, Karen, et Anna Fenelon. « Application of Energy Dispersive X-ray Fluorescence Spectrometry to the Determination of Copper, Manganese, Zinc, and Sulfur in Grass (Lolium perenne) in Grazed Agricultural Systems ». Applied Spectroscopy 72, no 11 (20 juillet 2018) : 1661–73. http://dx.doi.org/10.1177/0003702818787165.

Texte intégral
Résumé :
Conventional methods for the determination of major nutrients and trace elements in grass rely on acid digestion followed by analysis using inductively coupled plasma optical emission spectrometry (ICP-OES), which can be both time consuming and costly. Energy dispersive X-ray fluorescence (EDXRF) spectrometry offers a rapid alternative that can determine multiple elements in a single scan. Copper, Mn, Zn, and S in grass samples were determined using EDXRF with a number of different calibration approaches using both empirical standards and the theoretical relationships between concentrations and intensities. Using an existing archive of 467 grass samples of known concentrations, a suite of 30 samples was selected as empirical grass standards to build a calibration set between sample concentrations and EDXRF intensities. The theoretical or standardless approach used the fundamental parameters method to determine element concentrations. To validate the two calibration methods, 59 samples were randomly selected from the same archive and database and analyzed by EDXRF. The measurements of Cu, Mn, Zn, and S were compared with the ICP-OES values using agreement statistics. An excellent correlation was observed between the concentrations determined by EDXRF and ICP-OES ( R > 0.90) regardless of the calibration approach. However, agreement and closeness to the true value varied and were assessed using agreement statistics. Across all elements, the empirically calibrated samples were in excellent agreement with the values determined by ICP-OES. The theoretical calibrations provided excellent agreement for Mn and Zn, but a degree of fixed and proportional bias was observed in the Cu and S values. Fixed bias was corrected by subtracting the computed bias from the EDXRF concentrations and improved the overall agreement. Similarly, proportional bias was corrected using the linear regression model to predict the corrected EDXRF values. This improved the overall agreement with the ICP-OES values for both Cu and S using corrected fundamental parameters calibrations. This study provides a practical basis for the use of EDXRF to determine Cu, Mn, Zn, and S in grass samples to monitor forage quality in grazed systems without the need for sample digestion. The observed fixed and proportional bias in the theoretical calibrations can be corrected provided that a good correlation exists between EDXRF and conventional methods.
Styles APA, Harvard, Vancouver, ISO, etc.
21

Rosa-González, Daniel, Elena Terlevich et Roberto Terlevich. « An empirical calibration of star formation rate estimators ». Monthly Notices of the Royal Astronomical Society 332, no 2 (mai 2002) : 283–95. http://dx.doi.org/10.1046/j.1365-8711.2002.05285.x.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
22

Kennicutt, Jr., Robert C., Fabio Bresolin, Howard French et Pierre Martin. « An Empirical Test and Calibration of HiiRegion Diagnostics ». Astrophysical Journal 537, no 2 (10 juillet 2000) : 589–612. http://dx.doi.org/10.1086/309075.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
23

Fuhrmann, Daniel R., et William H. Smith. « Empirical modeling and calibration of Fourier transform spectrometers ». Optical Engineering 42, no 8 (2003) : 2268. http://dx.doi.org/10.1117/1.1589755.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
24

Bequé, Artem, Kristof Coussement, Ross Gayler et Stefan Lessmann. « Approaches for credit scorecard calibration : An empirical analysis ». Knowledge-Based Systems 134 (octobre 2017) : 213–27. http://dx.doi.org/10.1016/j.knosys.2017.07.034.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
25

Valley, John W., Ilya N. Bindeman et William H. Peck. « Empirical calibration of oxygen isotope fractionation in zircon ». Geochimica et Cosmochimica Acta 67, no 17 (septembre 2003) : 3257–66. http://dx.doi.org/10.1016/s0016-7037(03)00090-5.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
26

TANIMURA, HIDETOSHI, et YUJI YAMADA. « AN EFFICIENT CALIBRATION METHOD FOR THE MULTI-FACTOR LIBOR MARKET MODEL AND ITS APPLICATION TO THE JAPANESE MARKET ». International Journal of Theoretical and Applied Finance 09, no 07 (novembre 2006) : 1123–39. http://dx.doi.org/10.1142/s0219024906003913.

Texte intégral
Résumé :
In this paper an efficient calibration method for the multi-factor LIBOR Market Model (LMM) is proposed and is applied for the Japanese interest rate market. At first the joint calibration method in the cap and swaption market is demonstrated using a new parameterization for the correlation matrix in the LMM. Then we implement the proposed methodology for calibrating the Japanese cap and swaption markets, where the computational procedure is shown to be tractable and provides a practical estimation for the implied correlation matrix in the LMM. The empirical analysis also illustrates that Black's swaption volatilities through our calibration fit the market data almost exactly and that the estimated implied correlation matrix is smooth and stable.
Styles APA, Harvard, Vancouver, ISO, etc.
27

Lieberman, Alvin. « Calibrations Requirements and Methods for Liquid-Borne Particle Counters ». Journal of the IEST 31, no 3 (1 mai 1988) : 34–36. http://dx.doi.org/10.17764/jiet.1.31.3.063155412224288w.

Texte intégral
Résumé :
This paper describes present U.S. practices for calibrating optical liquid-borne particle counters (APCs). Operation of these instruments is described briefly for both light extinction and scattering instruments in order to help the reader understand why empirical calibration is necessary. Calibration requirements are pointed out in terms of the need to verify both particle sizing and particle counting accuracy. Two calibration methods are currently used in the U.S. One is based on size and count response to a suspension of presized isotropic latex spheres. The other is based on APC adjustment to match the stated size distribution of a test dust polydisperse suspension at a specific concentration. Both methods are described and some advantages and problems are presented.
Styles APA, Harvard, Vancouver, ISO, etc.
28

Davies, Stephen, et John Loomis. « An Improved Method for Calibrating Purchase Intentions in Stated Preference Demand Models ». Journal of Agricultural and Applied Economics 42, no 4 (novembre 2010) : 679–93. http://dx.doi.org/10.1017/s1074070800003886.

Texte intégral
Résumé :
The Orbit demand model allows the magnitude of the calibration to stated purchase intentions to vary based on the magnitude of the stated quantities. Using an empirical example of stated trips, we find that the extent of calibration varies substantially with less correction needed at small stated trips (-25%) but larger corrections at higher quantities of stated visits (-48%). We extend the Orbit model to calculate consumer surplus per stated trip of $26. Combining the calibrations in stated trips and value per trip, the Orbit model provides estimates of annual benefits from 60% to 111% less than the count data model.
Styles APA, Harvard, Vancouver, ISO, etc.
29

Ruiz-Dern, L., C. Babusiaux, F. Arenou, C. Turon et R. Lallement. « Empirical photometric calibration of the Gaia red clump : Colours, effective temperature, and absolute magnitude ». Astronomy & ; Astrophysics 609 (janvier 2018) : A116. http://dx.doi.org/10.1051/0004-6361/201731572.

Texte intégral
Résumé :
Context. Gaia Data Release 1 allows the recalibration of standard candles such as the red clump stars. To use those stars, they first need to be accurately characterised. In particular, colours are needed to derive interstellar extinction. As no filter is available for the first Gaia data release and to avoid the atmosphere model mismatch, an empirical calibration is unavoidable. Aims. The purpose of this work is to provide the first complete and robust photometric empirical calibration of the Gaia red clump stars of the solar neighbourhood through colour–colour, effective temperature–colour, and absolute magnitude–colour relations from the Gaia, Johnson, 2MASS, Hipparcos, Tycho-2, APASS-SLOAN, and WISE photometric systems, and the APOGEE DR13 spectroscopic temperatures. Methods. We used a 3D extinction map to select low reddening red giants. To calibrate the colour–colour and the effective temperature–colour relations, we developed a MCMC method that accounts for all variable uncertainties and selects the best model for each photometric relation. We estimated the red clump absolute magnitude through the mode of a kernel-based distribution function. Results. We provide 20 colour versus G−Ks relations and the first Teff versus G−Ks calibration. We obtained the red clump absolute magnitudes for 15 photometric bands with, in particular, MKs = (−1.606 ± 0.009) and MG = (0.495 ± 0.009) + (1.121 ± 0.128)(G−Ks−2.1). We present a dereddened Gaia-TGAS HR diagram and use the calibrations to compare its red clump and its red giant branch bump with Padova isochrones.
Styles APA, Harvard, Vancouver, ISO, etc.
30

Zhu, Shan, Bang Wang, Wen Yu Liu et Hui Liang. « An Empirical Indoor Propagation Model for Underground Parking Area ». Advanced Materials Research 433-440 (janvier 2012) : 4865–68. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.4865.

Texte intégral
Résumé :
This paper presents an empirical indoor propagation model for underground parking area based on our extensive field measurements. Among several candidate empirical models, we choose the modified Keenan-Motley model for calibration, using channel power measurements at the 3G and 4G radio frequencies. Our calibration results can be used to provide a simple propagation model for wireless transmission planning, forecasting and quality control in indoor parking scenarios.
Styles APA, Harvard, Vancouver, ISO, etc.
31

Weinberg, Jonathan M., Stephen Crowley, Chad Gonnerman, Ian Vandewalker et Stacey Swain. « Intuition & ; Calibration ». Essays in Philosophy 13, no 1 (2012) : 257–84. http://dx.doi.org/10.5840/eip201213115.

Texte intégral
Résumé :
The practice of appealing to intuitive judgments concerning esoteric cases, long standard in analytic philosophy, has recently fallen on hard times. Various recent empirical results have suggested that philosophers are not currently able to distinguish good intuitions from bad. This paper evaluates one possible type of approach to this problematic methodological situation: calibration. Both critiquing and building on an argument from Robert Cummins, the paper explores what possible avenues may exist for the calibration of philosophical intuitions. It is argued that no good options are currently available, but leaves open the real possibility of such a calibration in the future.
Styles APA, Harvard, Vancouver, ISO, etc.
32

Hu, Yafei, Hung Q. Vu et David W. Hubble. « Evaluation of dielectric-based probes for expansive soils : application to Regina clay ». Canadian Geotechnical Journal 47, no 3 (mars 2010) : 346–58. http://dx.doi.org/10.1139/t09-104.

Texte intégral
Résumé :
Much experience has been gained with the use of the dielectric methods in granular or fine-grained soil with low to medium plasticity. Empirical equations were proposed to describe the relationship between water content and measured bulk dielectric constant of the soils. However, the proposed empirical equations are generally not considered applicable for highly plastic, expansive soils due to factors such as bound water and high electric conductivity. This paper presents calibration equations for various commercially available dielectric-based probes. The calibration curves have been determined through laboratory calibration using compacted specimens. The differences between the calibration curves and those predicted by the empirical equations, as well as those provided by the manufacturer, are assessed and discussed. The effect of temperature on the response of the probes was also studied.
Styles APA, Harvard, Vancouver, ISO, etc.
33

Dunkley Jones, Tom, Yvette L. Eley, William Thomson, Sarah E. Greene, Ilya Mandel, Kirsty Edgar et James A. Bendle. « OPTiMAL : a new machine learning approach for GDGT-based palaeothermometry ». Climate of the Past 16, no 6 (23 décembre 2020) : 2599–617. http://dx.doi.org/10.5194/cp-16-2599-2020.

Texte intégral
Résumé :
Abstract. In the modern oceans, the relative abundances of glycerol dialkyl glycerol tetraether (GDGT) compounds produced by marine archaeal communities show a significant dependence on the local sea surface temperature at the site of deposition. When preserved in ancient marine sediments, the measured abundances of these fossil lipid biomarkers thus have the potential to provide a geological record of long-term variability in planetary surface temperatures. Several empirical calibrations have been made between observed GDGT relative abundances in late Holocene core-top sediments and modern upper ocean temperatures. These calibrations form the basis of the widely used TEX86 palaeothermometer. There are, however, two outstanding problems with this approach: first the appropriate assignment of uncertainty to estimates of ancient sea surface temperatures based on the relationship of the ancient GDGT assemblage to the modern calibration dataset, and second, the problem of making temperature estimates beyond the range of the modern empirical calibrations (> 30 ∘C). Here we apply modern machine learning tools, including Gaussian process emulators and forward modelling, to develop a new mathematical approach we call OPTiMAL (Optimised Palaeothermometry from Tetraethers via MAchine Learning) to improve temperature estimation and the representation of uncertainty based on the relationship between ancient GDGT assemblage data and the structure of the modern calibration dataset. We reduce the root mean square uncertainty on temperature predictions (validated using the modern dataset) from ∼ ±6 ∘C using TEX86-based estimators to ±3.6 ∘C using Gaussian process estimators for temperatures below 30 ∘C. We also provide a new quantitative measure of the distance between an ancient GDGT assemblage and the nearest neighbour within the modern calibration dataset, as a test for significant non-analogue behaviour.
Styles APA, Harvard, Vancouver, ISO, etc.
34

Dors, Oli L. « Chemical abundances in Seyfert galaxies – VI. Empirical abundance calibration ». Monthly Notices of the Royal Astronomical Society 507, no 1 (30 juillet 2021) : 466–74. http://dx.doi.org/10.1093/mnras/stab2166.

Texte intégral
Résumé :
ABSTRACT We derived a bi-dimensional calibration between the emission-line ratios $R_{23}= ([\mathrm{ O}\, {\small {\rm II}}]\,\lambda 3726 +\lambda 3729 +[\mathrm{ O}\mathrm{ }\, {\small {\rm III}}]\,\lambda 4959 + \lambda 5007)/\rm H\,\beta$, ${\it P}=[([\mathrm{ O}\, {\small {\rm III}}]\,\lambda 4959+\lambda 5007)/{\rm H}\,\beta ]/R_{23}$ and the oxygen abundance relative to hydrogen (O/H) in the gas phase of Seyfert 1 and 2 nuclei. In view of this, emission-line intensity ratios for a sample of objects taken from the Sloan Digital Sky Survey Data Release 7 measured by the MPA/JHU group and direct estimates of O/H based on Te-method, adapted for active galactic nuclei (AGNs), are considered. We find no variation of R23 observed along the radii of AGNs, which shows that this line ratio is a good oxygen abundance (O/H) indicator for the class of objects considered in this work. The derived O/H = f(R23, P) relation produces O/H values similar to estimations via Te-method in a wide range of metallicities [$\rm 8.0 \: \lesssim \: 12+\log \,(O/H) \: \lesssim \: 9.2$]. Conversely to star-forming regions in the high-metallicity regime, R23 shows a positive correlation trend with O/H in AGNs. This indicates that the hardness of ionizing radiation is not affected by the metallicities in these objects or narrow-line regions are not significantly modified by changes in the spectral energy distribution due to metallicity variations.
Styles APA, Harvard, Vancouver, ISO, etc.
35

Ferraro, Francesco R., Elena Valenti, Oscar Straniero et Livia Origlia. « An Empirical Calibration of the Mixing‐Length Parameter α ». Astrophysical Journal 642, no 1 (mai 2006) : 225–29. http://dx.doi.org/10.1086/500803.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
36

Idiart, T. P., et J. A. De Freitas Pacheco. « Empirical Calibration of Metallicity Indices for Single Stellar Populations ». Astronomical Journal 109 (mai 1995) : 2218. http://dx.doi.org/10.1086/117447.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
37

HEINRICH, W., G. REHS et G. FRANZ. « Monazite-xenotime miscibility gap thermometry. I. An empirical calibration ». Journal of Metamorphic Geology 15, no 1 (janvier 1997) : 3–16. http://dx.doi.org/10.1111/j.1525-1314.1997.t01-1-00052.x.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
38

Ding, Keyue, et Rohana J. Karunamuni. « A linear empirical Bayes solution for the calibration problem ». Journal of Statistical Planning and Inference 119, no 2 (février 2004) : 421–47. http://dx.doi.org/10.1016/s0378-3758(02)00492-5.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
39

Nguyen, Minh Khoa, Steve Phelps et Wing Lon Ng. « Simulation based calibration using extended balanced augmented empirical likelihood ». Statistics and Computing 25, no 6 (3 septembre 2014) : 1093–112. http://dx.doi.org/10.1007/s11222-014-9506-9.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
40

Angeletos, George-Marios, David Laibson, Andrea Repetto, Jeremy Tobacman et Stephen Weinberg. « The Hyperbolic Consumption Model : Calibration, Simulation, and Empirical Evaluation ». Journal of Economic Perspectives 15, no 3 (1 août 2001) : 47–68. http://dx.doi.org/10.1257/jep.15.3.47.

Texte intégral
Résumé :
Laboratory and field studies of time preference find that discount rates are much greater in the short run than in the long run. Hyperbolic discount functions capture this property. This paper presents simulations of the savings and asset allocation choices of households with hyperbolic preferences. The behavior of the hyperbolic households is compared to the behavior of exponential households. The hyperbolic households borrow much more frequently in the revolving credit market. The hyperbolic households exhibit greater consumption income comovement and experience a greater drop in consumption around retirement. The hyperbolic simulations match observed consumption and balance sheet data much better than the exponential simulations.
Styles APA, Harvard, Vancouver, ISO, etc.
41

Abdul-Aziz, Omar I., Bruce N. Wilson et John S. Gulliver. « Calibration and Validation of an Empirical Dissolved Oxygen Model ». Journal of Environmental Engineering 133, no 7 (juillet 2007) : 698–710. http://dx.doi.org/10.1061/(asce)0733-9372(2007)133:7(698).

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
42

Schuemie, Martijn J., George Hripcsak, Patrick B. Ryan, David Madigan et Marc A. Suchard. « Robust empirical calibration of p -values using observational data ». Statistics in Medicine 35, no 22 (4 septembre 2016) : 3883–88. http://dx.doi.org/10.1002/sim.6977.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
43

Bojanowski, Jędrzej S., Marcello Donatelli, Andrew K. Skidmore et Anton Vrieling. « An auto-calibration procedure for empirical solar radiation models ». Environmental Modelling & ; Software 49 (novembre 2013) : 118–28. http://dx.doi.org/10.1016/j.envsoft.2013.08.002.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
44

Liu, Yukun, Changliang Zou et Zhaojun Wang. « Calibration of the empirical likelihood for high-dimensional data ». Annals of the Institute of Statistical Mathematics 65, no 3 (18 novembre 2012) : 529–50. http://dx.doi.org/10.1007/s10463-012-0384-7.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
45

Foschi, Paolo, et Andrea Pascucci. « Calibration of a path-dependent volatility model : Empirical tests ». Computational Statistics & ; Data Analysis 53, no 6 (avril 2009) : 2219–35. http://dx.doi.org/10.1016/j.csda.2008.10.042.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
46

Pavlovic, M. Z., A. Dobardzic, B. Vukotic et D. Urosevic. « Updated radio Σ−D relation for galactic supernova remnants ». Serbian Astronomical Journal, no 189 (2014) : 25–40. http://dx.doi.org/10.2298/saj1489025p.

Texte intégral
Résumé :
We present the updated empirical radio surface-brightness-to-diameter (? ? D) relation for supernova remnants (SNRs) in our Galaxy. Our original calibration sample of Galactic SNRs with independently determined distances (Pavlovic et al. 2013, hereafter Paper I) is reconsidered and updated with data which became available in the past two years. The orthogonal fitting procedure and probability-density-function-based (PDF) method are applied to the calibration sample in the log? ? logD plane. Non-standard orthogonal regression keeps the ??D and D?? relations invariant within estimated uncertainties. Our previous Monte Carlo simulations verified that the slopes of the empirical ??D relation should be determined by using the orthogonal regression, because of its good performances for data sets with severe scatter. The updated calibration sample contains 65 shell SNRs. 6 new Galactic SNRs are added to the sample from Paper I, one is omitted and distances are changed for 10 SNRs. The slope derived is here slightly steeper (? ? 5.2) than the ??D slope in Paper I (? ? 4.8). The PDF method relies on data points density maps which can provide more reliable calibrations that preserve more information contained in the calibration sample. We estimate distances to five new faint Galactic SNRs discovered for the first time by Canadian Galactic Plane Survey, and obtained distances of 2.3, 4.0, 1.3, 2.9 and 4.7 kiloparsecs for G108.5+11.0, G128.5+2.6, G149.5+3.2, G150.8+3.8 and G160.1?1.1, respectively. The updated empirical relation is used to estimate distances of 160 shell Galactic SNRs and new results change their distance scales up to 15 per cent, compared to the results from Paper I. The PDF calculation can provide even few times higher or lower values in comparison with the orthogonal fit, as it uses a totally different approach. However, on average, this difference is 32, 24 and 18 per cent for mode, median and mean distances.
Styles APA, Harvard, Vancouver, ISO, etc.
47

Kweon, Wonbin, SeongKu Kang et Hwanjo Yu. « Obtaining Calibrated Probabilities with Personalized Ranking Models ». Proceedings of the AAAI Conference on Artificial Intelligence 36, no 4 (28 juin 2022) : 4083–91. http://dx.doi.org/10.1609/aaai.v36i4.20326.

Texte intégral
Résumé :
For personalized ranking models, the well-calibrated probability of an item being preferred by a user has great practical value. While existing work shows promising results in image classification, probability calibration has not been much explored for personalized ranking. In this paper, we aim to estimate the calibrated probability of how likely a user will prefer an item. We investigate various parametric distributions and propose two parametric calibration methods, namely Gaussian calibration and Gamma calibration. Each proposed method can be seen as a post-processing function that maps the ranking scores of pre-trained models to well-calibrated preference probabilities, without affecting the recommendation performance. We also design the unbiased empirical risk minimization framework that guides the calibration methods to learning of true preference probability from the biased user-item interaction dataset. Extensive evaluations with various personalized ranking models on real-world datasets show that both the proposed calibration methods and the unbiased empirical risk minimization significantly improve the calibration performance.
Styles APA, Harvard, Vancouver, ISO, etc.
48

Cramer, M., H. J. Przybilla et A. Zurhorst. « UAV CAMERAS : OVERVIEW AND GEOMETRIC CALIBRATION BENCHMARK ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W6 (23 août 2017) : 85–92. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w6-85-2017.

Texte intégral
Résumé :
Different UAV platforms and sensors are used in mapping already, many of them equipped with (sometimes) modified cameras as known from the consumer market. Even though these systems normally fulfil their requested mapping accuracy, the question arises, which system performs best? This asks for a benchmark, to check selected UAV based camera systems in well-defined, reproducible environments. Such benchmark is tried within this work here. Nine different cameras used on UAV platforms, representing typical camera classes, are considered. The focus is laid on the geometry here, which is tightly linked to the process of geometrical calibration of the system. In most applications the calibration is performed in-situ, i.e. calibration parameters are obtained as part of the project data itself. This is often motivated because consumer cameras do not keep constant geometry, thus, cannot be seen as metric cameras. Still, some of the commercial systems are quite stable over time, as it was proven from repeated (terrestrial) calibrations runs. Already (pre-)calibrated systems may offer advantages, especially when the block geometry of the project does not allow for a stable and sufficient in-situ calibration. Especially for such scenario close to metric UAV cameras may have advantages. Empirical airborne test flights in a calibration field have shown how block geometry influences the estimated calibration parameters and how consistent the parameters from lab calibration can be reproduced.
Styles APA, Harvard, Vancouver, ISO, etc.
49

Dembélé, A., J. L. Bertrand-Krajewski, C. Becouze et B. Barillon. « A new empirical model for stormwater TSS event mean concentrations (EMCs) ». Water Science and Technology 64, no 9 (1 novembre 2011) : 1926–34. http://dx.doi.org/10.2166/wst.2011.187.

Texte intégral
Résumé :
An empirical model for TSS event mean concentrations in storm weather discharges has been derived from the analysis of data sets collected in two experimental catchments (Chassieu, separate system and Ecully, combined system) in Lyon, France. Preliminary tests have shown that the values of TSS EMCs were linked to the variable X =TP ×ADWP (TP rainfall depth, ADWP antecedent dry weather period) with two distinct behaviours under and above a threshold value of X named λ: EMCs are increasing if X < λ and are decreasing if X > λ. An empirical equation is proposed for both behaviours. A specific calibration method is used to calibrate λ while the 4 other parameters of the model are calibrated by means of the Levenberg-Marquardt algorithm. The calibration results obtained with 8 events in both sites indicate that the model calibration is satisfactory: Nash Sutcliffe coefficients are all above 0.7. Monte Carlo simulations indicate a low variability of the model parameters for both sites. The model verification with 5 events in Chassieu shows maximum levels of uncertainty of approximately 20%, equivalent to levels of uncertainty observed in the calibration phase.
Styles APA, Harvard, Vancouver, ISO, etc.
50

González-Lemos, Saúl, José Guitián, Miguel-Ángel Fuertes, José-Abel Flores et Heather M. Stoll. « Technical note : An empirical method for absolute calibration of coccolith thickness ». Biogeosciences 15, no 4 (22 février 2018) : 1079–91. http://dx.doi.org/10.5194/bg-15-1079-2018.

Texte intégral
Résumé :
Abstract. As major calcifiers in the open ocean, coccolithophores play a key role in the marine carbon cycle. Because they may be sensitive to changing CO2 and ocean acidification, there is significant interest in quantifying past and present variations in their cellular calcification by quantifying the thickness of the coccoliths or calcite plates that cover their cells. Polarized light microscopy has emerged as a key tool for quantifying the thickness of these calcite plates, but the reproducibility and accuracy of such determinations has been limited by the absence of suitable calibration materials in the thickness range of coccoliths (0–4 µm). Here, we describe the fabrication of a calcite wedge with a constant slope over this thickness range, and the independent determination of calcite thickness along the wedge profile. We show how the calcite wedge provides more robust calibrations in the 0 to 1.55 µm range than previous approaches using rhabdoliths. We show the particular advantages of the calcite wedge approach for developing equations to relate thickness to the interference colors that arise in calcite in the thickness range between 1.55 and 4 µm. The calcite wedge approach can be applied to develop equations relevant to the particular light spectra and intensity of any polarized light microscope system and could significantly improve inter-laboratory data comparability.
Styles APA, Harvard, Vancouver, ISO, etc.
Vous pouvez également être intéressé par les bibliographies sur le sujet « Empirical calibration » pour d’autres types de sources :
Thèses
Nous offrons des réductions sur tous les plans premium pour les auteurs dont les œuvres sont incluses dans des sélections littéraires thématiques. Contactez-nous pour obtenir un code promo unique!

Vers la bibliographie