WorldWideScience

Sample records for surface sensitive analysis

  1. Sensitivity analysis

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003741.htm Sensitivity analysis To use the sharing features on this page, please enable JavaScript. Sensitivity analysis determines the effectiveness of antibiotics against microorganisms (germs) ...

  2. Sensitivity analysis of the surface water- groundwater interaction for the sandy area of the Netherlands

    NARCIS (Netherlands)

    Gomez del Campo, E.; Jousma, G.; Massop, H.T.L.

    1993-01-01

    The "Sensitivity Analysis of the Surface Water- Groundwater Interaction for the Sandy Area of the Netherlands" was carried out in the framework of a bilateral research project in support of the implementation of a nationwide geohydrological information system (REGIS) in the Netherlands. This

  3. Sensitivity analysis of the surface water- groundwater interaction for the sandy area of the Netherlands

    OpenAIRE

    Gomez del Campo, E.; Jousma, G.; Massop, H.T.L.

    1993-01-01

    The "Sensitivity Analysis of the Surface Water- Groundwater Interaction for the Sandy Area of the Netherlands" was carried out in the framework of a bilateral research project in support of the implementation of a nationwide geohydrological information system (REGIS) in the Netherlands. This project, conducted in cooperation between the TNO Institute for Applied Scientific Research (IGG-TNO) and !he Winand Staring Centre for Integrated Land, Soil and Water Research (SC-DLO), is aimed at defin...

  4. Fast and sensitive trace analysis of malachite green using a surface-enhanced Raman microfluidic sensor.

    Science.gov (United States)

    Lee, Sangyeop; Choi, Junghyun; Chen, Lingxin; Park, Byungchoon; Kyong, Jin Burm; Seong, Gi Hun; Choo, Jaebum; Lee, Yeonjung; Shin, Kyung-Hoon; Lee, Eun Kyu; Joo, Sang-Woo; Lee, Kyeong-Hee

    2007-05-08

    A rapid and highly sensitive trace analysis technique for determining malachite green (MG) in a polydimethylsiloxane (PDMS) microfluidic sensor was investigated using surface-enhanced Raman spectroscopy (SERS). A zigzag-shaped PDMS microfluidic channel was fabricated for efficient mixing between MG analytes and aggregated silver colloids. Under the optimal condition of flow velocity, MG molecules were effectively adsorbed onto silver nanoparticles while flowing along the upper and lower zigzag-shaped PDMS channel. A quantitative analysis of MG was performed based on the measured peak height at 1615 cm(-1) in its SERS spectrum. The limit of detection, using the SERS microfluidic sensor, was found to be below the 1-2 ppb level and this low detection limit is comparable to the result of the LC-Mass detection method. In the present study, we introduce a new conceptual detection technology, using a SERS microfluidic sensor, for the highly sensitive trace analysis of MG in water.

  5. Mitigating the surface urban heat island: Mechanism study and sensitivity analysis

    Science.gov (United States)

    Meng, Chunlei

    2017-08-01

    In a surface urban heat island (SUHI), the urban land surface temperature (LST) is usually higher than the temperature of the surrounding rural areas due to human activities and surface characteristics. Because a SUHI has many adverse impacts on urban environment and human health, SUHI mitigation strategies are very important. This paper investigates the mechanism of a SUHI based on the basic physical laws that control the formation of a SUHI; five mitigation strategies are proposed, namely: sprinkling and watering; paving a pervious surface; reducing the anthropogenic heat (AH) release; using a "white roof"; increasing the fractional vegetation cover or leaf area index (LAI). To quantify the effect of these mitigation strategies, 26 sets of experiments are designed and implemented by running the integrated urban land model (IUM). The results of the sensitivity analysis indicate that sprinkling and watering is an effective measure for mitigating a SUHI for an entire day. Decreasing the AH release is also useful for both night- and daytime SUHI mitigation; however, the cooling extent is proportional to the diurnal cycle of AH. Increasing the albedo can reduce the LST in the daytime, especially when the solar radiation is significant; the cooling extent is approximately proportional to the diurnal cycle of the net radiation. Increasing the pervious surface percentage can mitigate the SUHI especially in the daytime. Increasing the fractional vegetation cover can mitigate the SUHI in the daytime but may aggravate the SUHI at night.

  6. 3-D description of fracture surfaces and stress-sensitivity analysis for naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.Q.; Jioa, D.; Meng, Y.F.; Fan, Y.

    1997-08-01

    Three kinds of reservoir cores (limestone, sandstone, and shale with natural fractures) were used to study the effect of morphology of fracture surfaces on stress sensitivity. The cores, obtained from the reservoirs with depths of 2170 to 2300 m, have fractures which are mated on a large scale, but unmated on a fine scale. A specially designed photoelectric scanner with a computer was used to describe the topography of the fracture surfaces. Then, theoretical analysis of the fracture closure was carried out based on the fracture topography generated. The scanning results show that the asperity has almost normal distributions for all three types of samples. For the tested samples, the fracture closure predicted by the elastic-contact theory is different from the laboratory measurements because plastic deformation of the aspirates plays an important role under the testing range of normal stresses. In this work, the traditionally used elastic-contact theory has been modified to better predict the stress sensitivity of reservoir fractures. Analysis shows that the standard deviation of the probability density function of asperity distribution has a great effect on the fracture closure rate.

  7. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Laxemar

    International Nuclear Information System (INIS)

    Aneljung, Maria; Sassner, Mona; Gustafsson, Lars-Goeran

    2007-11-01

    between measured and calculated surface water discharges, but the model generally underestimates the total runoff from the area. The model also overestimates the groundwater levels, and the modelled groundwater level amplitudes are too small in many boreholes. A number of likely or potential reasons for these deviations can be identified: The surface stream network description in the model is incomplete. This implies that too little overland water is drained from the area by the streams, which creates ponded areas in the model that do not exist in reality. These areas are characterized by large evaporation and infiltration, contributing to groundwater recharge and reducing transpiration from the groundwater table, in turn creating high and relatively stable groundwater levels compared to those measured at the site. In order to improve the agreement between measured and modelled surface water discharges, the evapotranspiration was reduced in the model; in effect, this implied a reduction of the potential evapotranspiration. This probably caused a larger groundwater recharge and less transpiration during summer, thereby reducing the variations in the modelled groundwater levels. If the MIKE 11 stream network is updated, the potential evapotranspiration could be increased again, such that the modelling of groundwater dynamics is improved. The bottom boundary condition and the hydraulic conductivity of the bedrock may have a large effect on model-calculated near-surface/surface water flows in Laxemar. A sensitivity analysis shows that lowering the hydraulic head at the bottom boundary (located at 150 metres below sea level) lowers the groundwater levels in the Quaternary deposits, but also implies smaller surface water discharges. Lowering the hydraulic conductivity of the bedrock would increase groundwater flows to Quaternary deposits in groundwater discharge areas, which raises groundwater levels and reduces fluctuation amplitudes. An alternative model approach, using a

  8. A Monte Carlo/response surface strategy for sensitivity analysis: application to a dynamic model of vegetative plant growth

    Science.gov (United States)

    Lim, J. T.; Gold, H. J.; Wilkerson, G. G.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1989-01-01

    We describe the application of a strategy for conducting a sensitivity analysis for a complex dynamic model. The procedure involves preliminary screening of parameter sensitivities by numerical estimation of linear sensitivity coefficients, followed by generation of a response surface based on Monte Carlo simulation. Application is to a physiological model of the vegetative growth of soybean plants. The analysis provides insights as to the relative importance of certain physiological processes in controlling plant growth. Advantages and disadvantages of the strategy are discussed.

  9. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Aneljung, Maria; Sassner, Mona; Gustafsson, Lars-Goeran (DHI Sverige AB, Lilla Bommen 1, SE-411 04 Goeteborg (Sweden))

    2007-11-15

    between measured and calculated surface water discharges, but the model generally underestimates the total runoff from the area. The model also overestimates the groundwater levels, and the modelled groundwater level amplitudes are too small in many boreholes. A number of likely or potential reasons for these deviations can be identified: The surface stream network description in the model is incomplete. This implies that too little overland water is drained from the area by the streams, which creates ponded areas in the model that do not exist in reality. These areas are characterized by large evaporation and infiltration, contributing to groundwater recharge and reducing transpiration from the groundwater table, in turn creating high and relatively stable groundwater levels compared to those measured at the site. In order to improve the agreement between measured and modelled surface water discharges, the evapotranspiration was reduced in the model; in effect, this implied a reduction of the potential evapotranspiration. This probably caused a larger groundwater recharge and less transpiration during summer, thereby reducing the variations in the modelled groundwater levels. If the MIKE 11 stream network is updated, the potential evapotranspiration could be increased again, such that the modelling of groundwater dynamics is improved. The bottom boundary condition and the hydraulic conductivity of the bedrock may have a large effect on model-calculated near-surface/surface water flows in Laxemar. A sensitivity analysis shows that lowering the hydraulic head at the bottom boundary (located at 150 metres below sea level) lowers the groundwater levels in the Quaternary deposits, but also implies smaller surface water discharges. Lowering the hydraulic conductivity of the bedrock would increase groundwater flows to Quaternary deposits in groundwater discharge areas, which raises groundwater levels and reduces fluctuation amplitudes. An alternative model approach, using a

  10. Land surface temperature downscaling using random forest regression: primary result and sensitivity analysis

    Science.gov (United States)

    Pan, Xin; Cao, Chen; Yang, Yingbao; Li, Xiaolong; Shan, Liangliang; Zhu, Xi

    2018-04-01

    The land surface temperature (LST) derived from thermal infrared satellite images is a meaningful variable in many remote sensing applications. However, at present, the spatial resolution of the satellite thermal infrared remote sensing sensor is coarser, which cannot meet the needs. In this study, LST image was downscaled by a random forest model between LST and multiple predictors in an arid region with an oasis-desert ecotone. The proposed downscaling approach was evaluated using LST derived from the MODIS LST product of Zhangye City in Heihe Basin. The primary result of LST downscaling has been shown that the distribution of downscaled LST matched with that of the ecosystem of oasis and desert. By the way of sensitivity analysis, the most sensitive factors to LST downscaling were modified normalized difference water index (MNDWI)/normalized multi-band drought index (NMDI), soil adjusted vegetation index (SAVI)/ shortwave infrared reflectance (SWIR)/normalized difference vegetation index (NDVI), normalized difference building index (NDBI)/SAVI and SWIR/NDBI/MNDWI/NDWI for the region of water, vegetation, building and desert, with LST variation (at most) of 0.20/-0.22 K, 0.92/0.62/0.46 K, 0.28/-0.29 K and 3.87/-1.53/-0.64/-0.25 K in the situation of +/-0.02 predictor perturbances, respectively.

  11. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Forsmark

    International Nuclear Information System (INIS)

    Aneljung, Maria; Gustafsson, Lars-Goeran

    2007-04-01

    . Differences in the aquifer refilling process subsequent to dry periods, for example a too slow refill when the groundwater table rises after dry summers. This may be due to local deviations in the applied pF-curves in the unsaturated zone description. Differences in near-surface groundwater elevations. For example, the calculated groundwater level reaches the ground surface during the fall and spring at locations where the measured groundwater depth is just below the ground surface. This may be due to the presence of near-surface high-conductive layers. A sensitivity analysis has been made on calibration parameters. For parameters that have 'global' effects, such as the hydraulic conductivity in the saturated zone, the analysis was performed using the 'full' model. For parameters with more local effects, such as parameters influencing the evapotranspiration and the net recharge, the model was scaled down to a column model, representing two different type areas. The most important conclusions that can be drawn from the sensitivity analysis are the following: The results indicate that the horizontal hydraulic conductivity generally should be increased at topographic highs, and reduced at local depressions in the topography. The results indicate that no changes should be made to the vertical hydraulic conductivity at locations where the horizontal conductivity has been increased, and that the vertical conductivity generally should be decreased where the horizontal conductivity has been decreased. The vegetation parameters that have the largest influence on the total groundwater recharge are the root mass distribution and the crop coefficient. The unsaturated zone parameter that have the largest influence on the total groundwater recharge is the effective porosity given in the pF-curve. In addition, the shape of the pF-curve above the water content at field capacity is also of great importance. The general conclusion is that the surrounding conditions have large effects on water

  12. Sensitivity analysis and development of calibration methodology for near-surface hydrogeology model of Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Aneljung, Maria; Gustafsson, Lars-Goeran [DHI Water and Environment AB, Goeteborg (Sweden)

    2007-04-15

    . Differences in the aquifer refilling process subsequent to dry periods, for example a too slow refill when the groundwater table rises after dry summers. This may be due to local deviations in the applied pF-curves in the unsaturated zone description. Differences in near-surface groundwater elevations. For example, the calculated groundwater level reaches the ground surface during the fall and spring at locations where the measured groundwater depth is just below the ground surface. This may be due to the presence of near-surface high-conductive layers. A sensitivity analysis has been made on calibration parameters. For parameters that have 'global' effects, such as the hydraulic conductivity in the saturated zone, the analysis was performed using the 'full' model. For parameters with more local effects, such as parameters influencing the evapotranspiration and the net recharge, the model was scaled down to a column model, representing two different type areas. The most important conclusions that can be drawn from the sensitivity analysis are the following: The results indicate that the horizontal hydraulic conductivity generally should be increased at topographic highs, and reduced at local depressions in the topography. The results indicate that no changes should be made to the vertical hydraulic conductivity at locations where the horizontal conductivity has been increased, and that the vertical conductivity generally should be decreased where the horizontal conductivity has been decreased. The vegetation parameters that have the largest influence on the total groundwater recharge are the root mass distribution and the crop coefficient. The unsaturated zone parameter that have the largest influence on the total groundwater recharge is the effective porosity given in the pF-curve. In addition, the shape of the pF-curve above the water content at field capacity is also of great importance. The general conclusion is that the surrounding conditions have

  13. Response surface methodology for sensitivity and uncertainty analysis: performance and perspectives

    International Nuclear Information System (INIS)

    Olivi, L.; Brunelli, F.; Cacciabue, P.C.; Parisi, P.

    1985-01-01

    Two main aspects have to be taken into account in studying a nuclear accident scenario when using nuclear safety codes as an information source. The first one concerns the behavior of the code response and the set of assumptions to be introduced for its modelling. The second one is connected with the uncertainty features of the code input, often modelled as a probability density function (pdf). The analyst can apply two well-defined approaches depending on whether he wants major emphasis put on either of the aspects. Response Surface Methodology uses polynomial and inverse polynomial models together with the theory of experimental design, expressly developed for the identification procedure. It constitutes a well-established body of techniques able to cover a wide spectrum of requirements, when the first aspect plays the crucial role in the definition of the objectives. Other techniques such as Latin hypercube sampling, stratified sampling or even random sampling can fit better, when the second aspect affects the reliability of the analysis. The ultimate goal for both approaches is the selection of the variable, i.e. the identification of the code input variables most effective on the output and the uncertainty propagation, i.e. the assessment of the pdf to be attributed to the code response. The main aim of this work is to present a sensitivity analysis method, already tested on a real case, sufficiently flexible to be applied in both approaches mentioned

  14. Reliability and Sensitivity Analysis for Laminated Composite Plate Using Response Surface Method

    International Nuclear Information System (INIS)

    Lee, Seokje; Kim, Ingul; Jang, Moonho; Kim, Jaeki; Moon, Jungwon

    2013-01-01

    Advanced fiber-reinforced laminated composites are widely used in various fields of engineering to reduce weight. The material property of each ply is well known; specifically, it is known that ply is less reliable than metallic materials and very sensitive to the loading direction. Therefore, it is important to consider this uncertainty in the design of laminated composites. In this study, reliability analysis is conducted using Callosum and Meatball interactions for a laminated composite plate for the case in which the tip deflection is the design requirement and the material property is a random variable. Furthermore, the efficiency and accuracy of the approximation method is identified, and a probabilistic sensitivity analysis is conducted. As a result, we can prove the applicability of the advanced design method for the stabilizer of an underwater vehicle

  15. Reliability and Sensitivity Analysis for Laminated Composite Plate Using Response Surface Method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seokje; Kim, Ingul [Chungnam National Univ., Daejeon (Korea, Republic of); Jang, Moonho; Kim, Jaeki; Moon, Jungwon [LIG Nex1, Yongin (Korea, Republic of)

    2013-04-15

    Advanced fiber-reinforced laminated composites are widely used in various fields of engineering to reduce weight. The material property of each ply is well known; specifically, it is known that ply is less reliable than metallic materials and very sensitive to the loading direction. Therefore, it is important to consider this uncertainty in the design of laminated composites. In this study, reliability analysis is conducted using Callosum and Meatball interactions for a laminated composite plate for the case in which the tip deflection is the design requirement and the material property is a random variable. Furthermore, the efficiency and accuracy of the approximation method is identified, and a probabilistic sensitivity analysis is conducted. As a result, we can prove the applicability of the advanced design method for the stabilizer of an underwater vehicle.

  16. On understanding the relationship between structure in the potential surface and observables in classical dynamics: A functional sensitivity analysis approach

    International Nuclear Information System (INIS)

    Judson, R.S.; Rabitz, H.

    1987-01-01

    The relationship between structure in the potential surface and classical mechanical observables is examined by means of functional sensitivity analysis. Functional sensitivities provide maps of the potential surface, highlighting those regions that play the greatest role in determining the behavior of observables. A set of differential equations for the sensitivities of the trajectory components are derived. These are then solved using a Green's function method. It is found that the sensitivities become singular at the trajectory turning points with the singularities going as eta -3 /sup // 2 , with eta being the distance from the nearest turning point. The sensitivities are zero outside of the energetically and dynamically allowed region of phase space. A second set of equations is derived from which the sensitivities of observables can be directly calculated. An adjoint Green's function technique is employed, providing an efficient method for numerically calculating these quantities. Sensitivity maps are presented for a simple collinear atom--diatom inelastic scattering problem and for two Henon--Heiles type Hamiltonians modeling

  17. Parameter sensitivity analysis of a 1-D cold region lake model for land-surface schemes

    Science.gov (United States)

    Guerrero, José-Luis; Pernica, Patricia; Wheater, Howard; Mackay, Murray; Spence, Chris

    2017-12-01

    Lakes might be sentinels of climate change, but the uncertainty in their main feedback to the atmosphere - heat-exchange fluxes - is often not considered within climate models. Additionally, these fluxes are seldom measured, hindering critical evaluation of model output. Analysis of the Canadian Small Lake Model (CSLM), a one-dimensional integral lake model, was performed to assess its ability to reproduce diurnal and seasonal variations in heat fluxes and the sensitivity of simulated fluxes to changes in model parameters, i.e., turbulent transport parameters and the light extinction coefficient (Kd). A C++ open-source software package, Problem Solving environment for Uncertainty Analysis and Design Exploration (PSUADE), was used to perform sensitivity analysis (SA) and identify the parameters that dominate model behavior. The generalized likelihood uncertainty estimation (GLUE) was applied to quantify the fluxes' uncertainty, comparing daily-averaged eddy-covariance observations to the output of CSLM. Seven qualitative and two quantitative SA methods were tested, and the posterior likelihoods of the modeled parameters, obtained from the GLUE analysis, were used to determine the dominant parameters and the uncertainty in the modeled fluxes. Despite the ubiquity of the equifinality issue - different parameter-value combinations yielding equivalent results - the answer to the question was unequivocal: Kd, a measure of how much light penetrates the lake, dominates sensible and latent heat fluxes, and the uncertainty in their estimates is strongly related to the accuracy with which Kd is determined. This is important since accurate and continuous measurements of Kd could reduce modeling uncertainty.

  18. Sensitivity analysis for near-surface disposal in argillaceous media using NAMMU-HYROCOIN Level 3-Test case 1

    International Nuclear Information System (INIS)

    Miller, D.R.; Paige, R.W.

    1988-07-01

    HYDROCOIN is an international project for comparing groundwater flow models and modelling strategies. Level 3 of the project concerns the application of groundwater flow models to repository performance assessment with emphasis on the treatment of sensitivity and uncertainty in models and data. Level 3, test case 1 concerns sensitivity analysis of the groundwater flow around a radioactive waste repository situated in a near surface argillaceous formation. Work on this test case has been carried out by Harwell and will be reported in full in the near future. This report presents the results obtained using the computer program NAMMU. (author)

  19. Parameter Estimation and Sensitivity Analysis of an Urban Surface Energy Balance Parameterization at a Tropical Suburban Site

    Science.gov (United States)

    Harshan, S.; Roth, M.; Velasco, E.

    2014-12-01

    Forecasting of the urban weather and climate is of great importance as our cities become more populated and considering the combined effects of global warming and local land use changes which make urban inhabitants more vulnerable to e.g. heat waves and flash floods. In meso/global scale models, urban parameterization schemes are used to represent the urban effects. However, these schemes require a large set of input parameters related to urban morphological and thermal properties. Obtaining all these parameters through direct measurements are usually not feasible. A number of studies have reported on parameter estimation and sensitivity analysis to adjust and determine the most influential parameters for land surface schemes in non-urban areas. Similar work for urban areas is scarce, in particular studies on urban parameterization schemes in tropical cities have so far not been reported. In order to address above issues, the town energy balance (TEB) urban parameterization scheme (part of the SURFEX land surface modeling system) was subjected to a sensitivity and optimization/parameter estimation experiment at a suburban site in, tropical Singapore. The sensitivity analysis was carried out as a screening test to identify the most sensitive or influential parameters. Thereafter, an optimization/parameter estimation experiment was performed to calibrate the input parameter. The sensitivity experiment was based on the "improved Sobol's global variance decomposition method" . The analysis showed that parameters related to road, roof and soil moisture have significant influence on the performance of the model. The optimization/parameter estimation experiment was performed using the AMALGM (a multi-algorithm genetically adaptive multi-objective method) evolutionary algorithm. The experiment showed a remarkable improvement compared to the simulations using the default parameter set. The calibrated parameters from this optimization experiment can be used for further model

  20. Sensitivity Analysis of the Surface Runoff Coefficient of HiPIMS in Simulating Flood Processes in a Large Basin

    Directory of Open Access Journals (Sweden)

    Yueling Wang

    2018-03-01

    Full Text Available To simulate flood processes at the basin level, the GPU-based High-Performance Integrated Hydrodynamic Modelling System (HiPIMS is gaining interest as computational capability increases. However, the difficulty of coping with rainfall input to HiPIMS reduces the possibility of acquiring a satisfactory simulation accuracy. The objective of this study is to test the sensitivity of the surface runoff coefficient in the HiPIMS source term in the Misai basin with an area of 797 km2 in south China. To achieve this, the basin was divided into 909,824 grid cells, to each of which a Manning coefficient was assigned based on its land use type interpreted from remote sensing data. A sensitivity analysis was conducted for three typical flood processes under four types of surface runoff coefficients, assumed a priori, upon three error functions. The results demonstrate the crucial role of the surface runoff coefficient in achieving better simulation accuracy and reveal that this coefficient varies with flood scale and is unevenly distributed over the basin.

  1. Sensitivity analysis of brain morphometry based on MRI-derived surface models

    Science.gov (United States)

    Klein, Gregory J.; Teng, Xia; Schoenemann, P. T.; Budinger, Thomas F.

    1998-07-01

    Quantification of brain structure is important for evaluating changes in brain size with growth and aging and for characterizing neurodegeneration disorders. Previous quantification efforts using ex vivo techniques suffered considerable error due to shrinkage of the cerebrum after extraction from the skull, deformation of slices during sectioning, and numerous other factors. In vivo imaging studies of brain anatomy avoid these problems and allow repetitive studies following progression of brain structure changes due to disease or natural processes. We have developed a methodology for obtaining triangular mesh models of the cortical surface from MRI brain datasets. The cortex is segmented from nonbrain tissue using a 2D region-growing technique combined with occasional manual edits. Once segmented, thresholding and image morphological operations (erosions and openings) are used to expose the regions between adjacent surfaces in deep cortical folds. A 2D region- following procedure is then used to find a set of contours outlining the cortical boundary on each slice. The contours on all slices are tiled together to form a closed triangular mesh model approximating the cortical surface. This model can be used for calculation of cortical surface area and volume, as well as other parameters of interest. Except for the initial segmentation of the cortex from the skull, the technique is automatic and requires only modest computation time on modern workstations. Though the use of image data avoids many of the pitfalls of ex vivo and sectioning techniques, our MRI-based technique is still vulnerable to errors that may impact the accuracy of estimated brain structure parameters. Potential inaccuracies include segmentation errors due to incorrect thresholding, missed deep sulcal surfaces, falsely segmented holes due to image noise and surface tiling artifacts. The focus of this paper is the characterization of these errors and how they affect measurements of cortical surface

  2. Automated Measurement for Sensitivity Analysis of Runoff-Sediment Load at Varying Surface Gradients

    Directory of Open Access Journals (Sweden)

    Imanogor P.A.

    2015-07-01

    Full Text Available Direct measurement of surface runoff is often associated with errors and inaccuracies which results to unreliable hydrological data. An automatic Runoff-meter using tipping buckets arrangement calibrated to tip 0.14 liter of runoff water per tip with an accuracy of ± 0.001 litre was used to measure surface runoff from a steel bounded soil tray of dimension (1200 mm X 900 mm X 260 mm filled with sand loamy to the depth of 130 mm and inclined at angle (0 0 , 5 0 ,12 0 and 15 0 horizontal to the instrument. The effect of varying angles of inclination on runoff intensity, sediment loss rate and sediment loss is significant at 5 % confidence level, while surface runoff is not significant at 5 % confidence level. Total highest sediment loss of 458.2 g and 313.4 g were observed at angle 15 0 and 12 0 respectively. Total surface runoff of 361.5 mm and 445.8 mm were generated at inclined angle of 0 0 and 5 0 , while at angle 12 0 and 15 0 , 564.3 mm and 590.0 mm of surface runoff were generated. In addition, runoff intensity and sediment loss rate were highest at angle 15 0 , while the lowest values of 1.5mm/min and 5.43 g/min were obtained at angle of inclination 5 0 . The results showed that strong relationship existed among the hydrological variables as a result of subjecting the steel bounded soil tray to different angles of inclination. Such results would provide useful data for the running of physics-based deterministic model of surface runoff and erosion which will be useful for the design of hydrological structures, land use planning and management.

  3. Sensitivity analysis of surface ozone to emission controls in Beijing and its neighboring area during the 2008 Olympic Games.

    Science.gov (United States)

    Gao, Yi; Zhang, Meigen

    2012-01-01

    The regional air quality modeling system RAMS (regional atmospheric modeling system)-CMAQ (community multi-scale air quality modeling system) is applied to analyze temporal and spatial variations in surface ozone concentration over Beijing and its surrounding region from July to October 2008. Comparison of simulated and observed meteorological elements and concentration of nitrogen oxides (NOx) and ozone at one urban site and three rural sites during Olympic Games show that model can generally reproduce the main observed feature of wind, temperature and ozone, but NOx concentration is overestimated. Although ozone concentration decreased during Olympics, high ozone episodes occurred on 24 July and 24 August with concentration of 360 and 245 microg/m3 at Aoyuncun site, respectively. The analysis of sensitive test, with and without emission controls, shows that emission controls could reduce ozone concentration in the afternoon when ozone concentration was highest but increase it at night and in the morning. The evolution of the weather system during the ozone episodes (24 July and 24 August) indicates that hot and dry air and a stable weak pressure field intensified the production of ozone and allowed it to accumulate. Process analysis at the urban site and rural site shows that under favorable weather condition on 24 August, horizontal transport was the main contributor of the rural place and the pollution from the higher layer would be transported to the surface layer. On 24 July, as the wind velocity was smaller, the impact of transport on the rural place was not obvious.

  4. Sensitivity and uncertainty analysis

    CERN Document Server

    Cacuci, Dan G; Navon, Ionel Michael

    2005-01-01

    As computer-assisted modeling and analysis of physical processes have continued to grow and diversify, sensitivity and uncertainty analyses have become indispensable scientific tools. Sensitivity and Uncertainty Analysis. Volume I: Theory focused on the mathematical underpinnings of two important methods for such analyses: the Adjoint Sensitivity Analysis Procedure and the Global Adjoint Sensitivity Analysis Procedure. This volume concentrates on the practical aspects of performing these analyses for large-scale systems. The applications addressed include two-phase flow problems, a radiative c

  5. Numerical Simulation of Heavy Rainfall in August 2014 over Japan and Analysis of Its Sensitivity to Sea Surface Temperature

    Directory of Open Access Journals (Sweden)

    Yuki Minamiguchi

    2018-02-01

    Full Text Available This study evaluated the performance of the Weather Research and Forecasting (WRF model version 3.7 for simulating a series of rainfall events in August 2014 over Japan and investigated the impact of uncertainty in sea surface temperature (SST on simulated rainfall in the record-high precipitation period. WRF simulations for the heavy rainfall were conducted for six different cases. The heavy rainfall events caused by typhoons and rain fronts were similarly accurately reproduced by three cases: the TQW_5km case with grid nudging for air temperature, humidity, and wind and with a horizontal resolution of 5 km; W_5km with wind nudging and 5-km resolution; and W_2.5km with wind nudging and 2.5-km resolution. Because the nudging for air temperature and humidity in TQW_5km suppresses the influence of SST change, and because W_2.5km requires larger computational load, W_5km was selected as the baseline case for a sensitivity analysis of SST. In the sensitivity analysis, SST around Japan was homogeneously changed by 1 K from the original SST data. The analysis showed that the SST increase led to a larger amount of precipitation in the study period in Japan, with the mean increase rate of precipitation being 13 ± 8% K−1. In addition, 99 percentile precipitation (100 mm d−1 in the baseline case increased by 13% K−1 of SST warming. These results also indicate that an uncertainty of approximately 13% in the simulated heavy rainfall corresponds to an uncertainty of 1 K in SST data around Japan in the study period.

  6. Sensitivity analysis of surface ozone to emission controls in Beijing and its neighboring area during the 2008 Olympic Games

    Institute of Scientific and Technical Information of China (English)

    Yi Gao; Meigen Zhang

    2012-01-01

    The regional air quality modeling system RAMS (Regional Atmospheric Modeling System)-CMAQ (Community Multi-scale Air Quality modeling system) is applied to analyze temporal and spatial variations in surface ozone concentration over Beijing and its surrounding region from July to October 2008.Comparison of simulated and observed meteorological elements and concentration of nitrogen oxides (NOx) and ozone at one urban site and three rural sites during Olympic Games show that model can generally reproduce the main observed feature of wind,temperature and ozone,but NOx concentration is overestimated.Although ozone concentration decreased during Olympics,high ozone episodes occurred on 24 July and 24 August with concentration of 360 and 245 μg/m3 at Aoyuncun site,respectively.The analysis of sensitive test,with and without emission controls,shows that emission controls could reduce ozone concentration in the afternoon when ozone concentration was highest but increase it at night and in the morning.The evolution of the weather system during the ozone episodes (24 July and 24 August) indicates that hot and dry air and a stable weak pressure field intensified the production of ozone and allowed it to accumulate.Process analysis at the urban site and rural site shows that under favorable weather condition on 24 August,horizontal transport was the main contributor of the rural place and the pollution from the higher layer would be transported to the surface layer.On 24 July,as the wind velocity was smaller,the impact of transport on the rural place was not obvious.

  7. WHAT IF (Sensitivity Analysis

    Directory of Open Access Journals (Sweden)

    Iulian N. BUJOREANU

    2011-01-01

    Full Text Available Sensitivity analysis represents such a well known and deeply analyzed subject that anyone to enter the field feels like not being able to add anything new. Still, there are so many facets to be taken into consideration.The paper introduces the reader to the various ways sensitivity analysis is implemented and the reasons for which it has to be implemented in most analyses in the decision making processes. Risk analysis is of outmost importance in dealing with resource allocation and is presented at the beginning of the paper as the initial cause to implement sensitivity analysis. Different views and approaches are added during the discussion about sensitivity analysis so that the reader develops an as thoroughly as possible opinion on the use and UTILITY of the sensitivity analysis. Finally, a round-up conclusion brings us to the question of the possibility of generating the future and analyzing it before it unfolds so that, when it happens it brings less uncertainty.

  8. Sensitivity Analysis Without Assumptions.

    Science.gov (United States)

    Ding, Peng; VanderWeele, Tyler J

    2016-05-01

    Unmeasured confounding may undermine the validity of causal inference with observational studies. Sensitivity analysis provides an attractive way to partially circumvent this issue by assessing the potential influence of unmeasured confounding on causal conclusions. However, previous sensitivity analysis approaches often make strong and untestable assumptions such as having an unmeasured confounder that is binary, or having no interaction between the effects of the exposure and the confounder on the outcome, or having only one unmeasured confounder. Without imposing any assumptions on the unmeasured confounder or confounders, we derive a bounding factor and a sharp inequality such that the sensitivity analysis parameters must satisfy the inequality if an unmeasured confounder is to explain away the observed effect estimate or reduce it to a particular level. Our approach is easy to implement and involves only two sensitivity parameters. Surprisingly, our bounding factor, which makes no simplifying assumptions, is no more conservative than a number of previous sensitivity analysis techniques that do make assumptions. Our new bounding factor implies not only the traditional Cornfield conditions that both the relative risk of the exposure on the confounder and that of the confounder on the outcome must satisfy but also a high threshold that the maximum of these relative risks must satisfy. Furthermore, this new bounding factor can be viewed as a measure of the strength of confounding between the exposure and the outcome induced by a confounder.

  9. Skin Sensitive Difference of Human Body Sections under Clothing--Multiple Analysis of Skin Surface Temperature Changes

    Institute of Scientific and Technical Information of China (English)

    李俊; 吴海燕; 张渭源

    2003-01-01

    A new researching method on clothing comfort perception is developed.By it the skin surface temperature changes and subjective psychological perception of human body sections stimulated by the same cold stimulation are studied.With the multiple comparison analysis method the changing laws of skin temperature of main human body sections is obtained.

  10. Interference and Sensitivity Analysis.

    Science.gov (United States)

    VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J; Halloran, M Elizabeth

    2014-11-01

    Causal inference with interference is a rapidly growing area. The literature has begun to relax the "no-interference" assumption that the treatment received by one individual does not affect the outcomes of other individuals. In this paper we briefly review the literature on causal inference in the presence of interference when treatments have been randomized. We then consider settings in which causal effects in the presence of interference are not identified, either because randomization alone does not suffice for identification, or because treatment is not randomized and there may be unmeasured confounders of the treatment-outcome relationship. We develop sensitivity analysis techniques for these settings. We describe several sensitivity analysis techniques for the infectiousness effect which, in a vaccine trial, captures the effect of the vaccine of one person on protecting a second person from infection even if the first is infected. We also develop two sensitivity analysis techniques for causal effects in the presence of unmeasured confounding which generalize analogous techniques when interference is absent. These two techniques for unmeasured confounding are compared and contrasted.

  11. Uncertainty Quantification and Regional Sensitivity Analysis of Snow-related Parameters in the Canadian LAnd Surface Scheme (CLASS)

    Science.gov (United States)

    Badawy, B.; Fletcher, C. G.

    2017-12-01

    The parameterization of snow processes in land surface models is an important source of uncertainty in climate simulations. Quantifying the importance of snow-related parameters, and their uncertainties, may therefore lead to better understanding and quantification of uncertainty within integrated earth system models. However, quantifying the uncertainty arising from parameterized snow processes is challenging due to the high-dimensional parameter space, poor observational constraints, and parameter interaction. In this study, we investigate the sensitivity of the land simulation to uncertainty in snow microphysical parameters in the Canadian LAnd Surface Scheme (CLASS) using an uncertainty quantification (UQ) approach. A set of training cases (n=400) from CLASS is used to sample each parameter across its full range of empirical uncertainty, as determined from available observations and expert elicitation. A statistical learning model using support vector regression (SVR) is then constructed from the training data (CLASS output variables) to efficiently emulate the dynamical CLASS simulations over a much larger (n=220) set of cases. This approach is used to constrain the plausible range for each parameter using a skill score, and to identify the parameters with largest influence on the land simulation in CLASS at global and regional scales, using a random forest (RF) permutation importance algorithm. Preliminary sensitivity tests indicate that snow albedo refreshment threshold and the limiting snow depth, below which bare patches begin to appear, have the highest impact on snow output variables. The results also show a considerable reduction of the plausible ranges of the parameters values and hence reducing their uncertainty ranges, which can lead to a significant reduction of the model uncertainty. The implementation and results of this study will be presented and discussed in details.

  12. Adaptation of an urban land surface model to a tropical suburban area: Offline evaluation, sensitivity analysis, and optimization of TEB/ISBA (SURFEX)

    Science.gov (United States)

    Harshan, Suraj

    The main objective of the present thesis is the improvement of the TEB/ISBA (SURFEX) urban land surface model (ULSM) through comprehensive evaluation, sensitivity analysis, and optimization experiments using energy balance and radiative and air temperature data observed during 11 months at a tropical sub-urban site in Singapore. Overall the performance of the model is satisfactory, with a small underestimation of net radiation and an overestimation of sensible heat flux. Weaknesses in predicting the latent heat flux are apparent with smaller model values during daytime and the model also significantly underpredicts both the daytime peak and nighttime storage heat. Surface temperatures of all facets are generally overpredicted. Significant variation exists in the model behaviour between dry and wet seasons. The vegetation parametrization used in the model is inadequate to represent the moisture dynamics, producing unrealistically low latent heat fluxes during a particularly dry period. The comprehensive evaluation of the USLM shows the need for accurate estimation of input parameter values for present site. Since obtaining many of these parameters through empirical methods is not feasible, the present study employed a two step approach aimed at providing information about the most sensitive parameters and an optimized parameter set from model calibration. Two well established sensitivity analysis methods (global: Sobol and local: Morris) and a state-of-the-art multiobjective evolutionary algorithm (Borg) were employed for sensitivity analysis and parameter estimation. Experiments were carried out for three different weather periods. The analysis indicates that roof related parameters are the most important ones in controlling the behaviour of the sensible heat flux and net radiation flux, with roof and road albedo as the most influential parameters. Soil moisture initialization parameters are important in controlling the latent heat flux. The built (town) fraction

  13. Beyond sensitivity analysis

    DEFF Research Database (Denmark)

    Lund, Henrik; Sorknæs, Peter; Mathiesen, Brian Vad

    2018-01-01

    of electricity, which have been introduced in recent decades. These uncertainties pose a challenge to the design and assessment of future energy strategies and investments, especially in the economic assessment of renewable energy versus business-as-usual scenarios based on fossil fuels. From a methodological...... point of view, the typical way of handling this challenge has been to predict future prices as accurately as possible and then conduct a sensitivity analysis. This paper includes a historical analysis of such predictions, leading to the conclusion that they are almost always wrong. Not only...... are they wrong in their prediction of price levels, but also in the sense that they always seem to predict a smooth growth or decrease. This paper introduces a new method and reports the results of applying it on the case of energy scenarios for Denmark. The method implies the expectation of fluctuating fuel...

  14. Chemical kinetic functional sensitivity analysis: Elementary sensitivities

    International Nuclear Information System (INIS)

    Demiralp, M.; Rabitz, H.

    1981-01-01

    Sensitivity analysis is considered for kinetics problems defined in the space--time domain. This extends an earlier temporal Green's function method to handle calculations of elementary functional sensitivities deltau/sub i//deltaα/sub j/ where u/sub i/ is the ith species concentration and α/sub j/ is the jth system parameter. The system parameters include rate constants, diffusion coefficients, initial conditions, boundary conditions, or any other well-defined variables in the kinetic equations. These parameters are generally considered to be functions of position and/or time. Derivation of the governing equations for the sensitivities and the Green's funciton are presented. The physical interpretation of the Green's function and sensitivities is given along with a discussion of the relation of this work to earlier research

  15. MOVES regional level sensitivity analysis

    Science.gov (United States)

    2012-01-01

    The MOVES Regional Level Sensitivity Analysis was conducted to increase understanding of the operations of the MOVES Model in regional emissions analysis and to highlight the following: : the relative sensitivity of selected MOVES Model input paramet...

  16. EV range sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ostafew, C. [Azure Dynamics Corp., Toronto, ON (Canada)

    2010-07-01

    This presentation included a sensitivity analysis of electric vehicle components on overall efficiency. The presentation provided an overview of drive cycles and discussed the major contributors to range in terms of rolling resistance; aerodynamic drag; motor efficiency; and vehicle mass. Drive cycles that were presented included: New York City Cycle (NYCC); urban dynamometer drive cycle; and US06. A summary of the findings were presented for each of the major contributors. Rolling resistance was found to have a balanced effect on each drive cycle and proportional to range. In terms of aerodynamic drive, there was a large effect on US06 range. A large effect was also found on NYCC range in terms of motor efficiency and vehicle mass. figs.

  17. Chemically stable Au nanorods as probes for sensitive surface enhanced scattering (SERS) analysis of blue BIC ballpoint pens

    Science.gov (United States)

    Alyami, Abeer; Saviello, Daniela; McAuliffe, Micheal A. P.; Cucciniello, Raffaele; Mirabile, Antonio; Proto, Antonio; Lewis, Liam; Iacopino, Daniela

    2017-08-01

    Au nanorods were used as an alternative to commonly used Ag nanoparticles as Surface Enhanced Raman Scattering (SERS) probes for identification of dye composition of blue BIC ballpoint pens. When used in combination with Thin Layer Chromatography (TLC), Au nanorod colloids allowed identification of the major dye components of the BIC pen ink, otherwise not identifiable by normal Raman spectroscopy. Thanks to their enhanced chemical stability compared to Ag colloids, Au nanorods provided stable and reproducible SERS signals and allowed easy identification of phthalocyanine and triarylene dyes in the pen ink mixture. These findings were supported by FTIR and MALDI analyses, also performed on the pen ink. Furthermore, the self-assembly of Au nanorods into large area ordered superstructures allowed identification of BIC pen traces. SERS spectra of good intensity and high reproducibility were obtained using Au nanorod vertical arrays, due to the high density of hot spots and morphological reproducibility of these superstructures. These results open the way to the employment of SERS for fast screening analysis and for quantitative analysis of pens and faded pens which are relevant for the fields of forensic and art conservation sciences.

  18. The surface analysis methods

    International Nuclear Information System (INIS)

    Deville, J.P.

    1998-01-01

    Nowadays, there are a lot of surfaces analysis methods, each having its specificity, its qualities, its constraints (for instance vacuum) and its limits. Expensive in time and in investment, these methods have to be used deliberately. This article appeals to non specialists. It gives some elements of choice according to the studied information, the sensitivity, the use constraints or the answer to a precise question. After having recalled the fundamental principles which govern these analysis methods, based on the interaction between radiations (ultraviolet, X) or particles (ions, electrons) with matter, two methods will be more particularly described: the Auger electron spectroscopy (AES) and x-rays photoemission spectroscopy (ESCA or XPS). Indeed, they are the most widespread methods in laboratories, the easier for use and probably the most productive for the analysis of surface of industrial materials or samples submitted to treatments in aggressive media. (O.M.)

  19. Soil heat flux calculation for sunlit and shaded surfaces under row crops: 1 - Model Development and sensitivity analysis

    Science.gov (United States)

    Soil heat flux at the surface (G0) is strongly influenced by whether the soil is shaded or sunlit, and therefore can have large spatial variability for incomplete vegetation cover, such as across the interrows of row crops. Most practical soil-plant-atmosphere energy balance models calculate G0 as a...

  20. Assessment of the contamination of drinking water supply wells by pesticides from surface water resources using a finite element reactive transport model and global sensitivity analysis techniques

    DEFF Research Database (Denmark)

    Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

    2013-01-01

    A reactive transport model is employed to evaluate the potential for contamination of drinking water wells by surface water pollution. The model considers various geologic settings, includes sorption and degradation processes and is tested by comparison with data from a tracer experiment where...... fluorescein dye injected in a river is monitored at nearby drinking water wells. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and relatively persistent, glyphosate (Roundup), a newer biodegradable and strongly sorbing pesticide, and its degradation product AMPA. Global...... sensitivity analysis using the Morris method is employed to identify the dominant model parameters. Results show that the characteristics of clay aquitards (degree of fracturing and thickness), pollutant properties and well depths are crucial factors when evaluating the risk of drinking water well...

  1. Independent Subspace Analysis of the Sea Surface Temperature Variability: Non-Gaussian Sources and Sensitivity to Sampling and Dimensionality

    Directory of Open Access Journals (Sweden)

    Carlos A. L. Pires

    2017-01-01

    Full Text Available We propose an expansion of multivariate time-series data into maximally independent source subspaces. The search is made among rotations of prewhitened data which maximize non-Gaussianity of candidate sources. We use a tensorial invariant approximation of the multivariate negentropy in terms of a linear combination of squared coskewness and cokurtosis. By solving a high-order singular value decomposition problem, we extract the axes associated with most non-Gaussianity. Moreover, an estimate of the Gaussian subspace is provided by the trailing singular vectors. The independent subspaces are obtained through the search of “quasi-independent” components within the estimated non-Gaussian subspace, followed by the identification of groups with significant joint negentropies. Sources result essentially from the coherency of extremes of the data components. The method is then applied to the global sea surface temperature anomalies, equatorward of 65°, after being tested with non-Gaussian surrogates consistent with the data anomalies. The main emerging independent components and subspaces, supposedly generated by independent forcing, include different variability modes, namely, The East-Pacific, the Central Pacific, and the Atlantic Niños, the Atlantic Multidecadal Oscillation, along with the subtropical dipoles in the Indian, South Pacific, and South-Atlantic oceans. Benefits and usefulness of independent subspaces are then discussed.

  2. Maternal sensitivity: a concept analysis.

    Science.gov (United States)

    Shin, Hyunjeong; Park, Young-Joo; Ryu, Hosihn; Seomun, Gyeong-Ae

    2008-11-01

    The aim of this paper is to report a concept analysis of maternal sensitivity. Maternal sensitivity is a broad concept encompassing a variety of interrelated affective and behavioural caregiving attributes. It is used interchangeably with the terms maternal responsiveness or maternal competency, with no consistency of use. There is a need to clarify the concept of maternal sensitivity for research and practice. A search was performed on the CINAHL and Ovid MEDLINE databases using 'maternal sensitivity', 'maternal responsiveness' and 'sensitive mothering' as key words. The searches yielded 54 records for the years 1981-2007. Rodgers' method of evolutionary concept analysis was used to analyse the material. Four critical attributes of maternal sensitivity were identified: (a) dynamic process involving maternal abilities; (b) reciprocal give-and-take with the infant; (c) contingency on the infant's behaviour and (d) quality of maternal behaviours. Maternal identity and infant's needs and cues are antecedents for these attributes. The consequences are infant's comfort, mother-infant attachment and infant development. In addition, three positive affecting factors (social support, maternal-foetal attachment and high self-esteem) and three negative affecting factors (maternal depression, maternal stress and maternal anxiety) were identified. A clear understanding of the concept of maternal sensitivity could be useful for developing ways to enhance maternal sensitivity and to maximize the developmental potential of infants. Knowledge of the attributes of maternal sensitivity identified in this concept analysis may be helpful for constructing measuring items or dimensions.

  3. To Fill or Not to Fill: Sensitivity Analysis of the Influence of Resolution and Hole Filling on Point Cloud Surface Modeling and Individual Rockfall Event Detection

    Directory of Open Access Journals (Sweden)

    Michael J. Olsen

    2015-09-01

    Full Text Available Monitoring unstable slopes with terrestrial laser scanning (TLS has been proven effective. However, end users still struggle immensely with the efficient processing, analysis, and interpretation of the massive and complex TLS datasets. Two recent advances described in this paper now improve the ability to work with TLS data acquired on steep slopes. The first is the improved processing of TLS data to model complex topography and fill holes. This processing step results in a continuous topographic surface model that seamlessly characterizes the rock and soil surface. The second is an advance in the automated interpretation of the surface model in such a way that a magnitude and frequency relationship of rockfall events can be quantified, which can be used to assess maintenance strategies and forecast costs. The approach is applied to unstable highway slopes in the state of Alaska, U.S.A. to evaluate its effectiveness. Further, the influence of the selected model resolution and degree of hole filling on the derived slope metrics were analyzed. In general, model resolution plays a pivotal role in the ability to detect smaller rockfall events when developing magnitude-frequency relationships. The total volume estimates are also influenced by model resolution, but were comparatively less sensitive. In contrast, hole filling had a noticeable effect on magnitude-frequency relationships but to a lesser extent than modeling resolution. However, hole filling yielded a modest increase in overall volumetric quantity estimates. Optimal analysis results occur when appropriately balancing high modeling resolution with an appropriate level of hole filling.

  4. Global optimization and sensitivity analysis

    International Nuclear Information System (INIS)

    Cacuci, D.G.

    1990-01-01

    A new direction for the analysis of nonlinear models of nuclear systems is suggested to overcome fundamental limitations of sensitivity analysis and optimization methods currently prevalent in nuclear engineering usage. This direction is toward a global analysis of the behavior of the respective system as its design parameters are allowed to vary over their respective design ranges. Presented is a methodology for global analysis that unifies and extends the current scopes of sensitivity analysis and optimization by identifying all the critical points (maxima, minima) and solution bifurcation points together with corresponding sensitivities at any design point of interest. The potential applicability of this methodology is illustrated with test problems involving multiple critical points and bifurcations and comprising both equality and inequality constraints

  5. Sensitivity analysis of EQ3

    International Nuclear Information System (INIS)

    Horwedel, J.E.; Wright, R.Q.; Maerker, R.E.

    1990-01-01

    A sensitivity analysis of EQ3, a computer code which has been proposed to be used as one link in the overall performance assessment of a national high-level waste repository, has been performed. EQ3 is a geochemical modeling code used to calculate the speciation of a water and its saturation state with respect to mineral phases. The model chosen for the sensitivity analysis is one which is used as a test problem in the documentation of the EQ3 code. Sensitivities are calculated using both the CHAIN and ADGEN options of the GRESS code compiled under G-float FORTRAN on the VAX/VMS and verified by perturbation runs. The analyses were performed with a preliminary Version 1.0 of GRESS which contains several new algorithms that significantly improve the application of ADGEN. Use of ADGEN automates the implementation of the well-known adjoint technique for the efficient calculation of sensitivities of a given response to all the input data. Application of ADGEN to EQ3 results in the calculation of sensitivities of a particular response to 31,000 input parameters in a run time of only 27 times that of the original model. Moreover, calculation of the sensitivities for each additional response increases this factor by only 2.5 percent. This compares very favorably with a running-time factor of 31,000 if direct perturbation runs were used instead. 6 refs., 8 tabs

  6. High order depletion sensitivity analysis

    International Nuclear Information System (INIS)

    Naguib, K.; Adib, M.; Morcos, H.N.

    2002-01-01

    A high order depletion sensitivity method was applied to calculate the sensitivities of build-up of actinides in the irradiated fuel due to cross-section uncertainties. An iteration method based on Taylor series expansion was applied to construct stationary principle, from which all orders of perturbations were calculated. The irradiated EK-10 and MTR-20 fuels at their maximum burn-up of 25% and 65% respectively were considered for sensitivity analysis. The results of calculation show that, in case of EK-10 fuel (low burn-up), the first order sensitivity was found to be enough to perform an accuracy of 1%. While in case of MTR-20 (high burn-up) the fifth order was found to provide 3% accuracy. A computer code SENS was developed to provide the required calculations

  7. Sensitivity Analysis of Simulation Models

    NARCIS (Netherlands)

    Kleijnen, J.P.C.

    2009-01-01

    This contribution presents an overview of sensitivity analysis of simulation models, including the estimation of gradients. It covers classic designs and their corresponding (meta)models; namely, resolution-III designs including fractional-factorial two-level designs for first-order polynomial

  8. Sensitivity analysis using probability bounding

    International Nuclear Information System (INIS)

    Ferson, Scott; Troy Tucker, W.

    2006-01-01

    Probability bounds analysis (PBA) provides analysts a convenient means to characterize the neighborhood of possible results that would be obtained from plausible alternative inputs in probabilistic calculations. We show the relationship between PBA and the methods of interval analysis and probabilistic uncertainty analysis from which it is jointly derived, and indicate how the method can be used to assess the quality of probabilistic models such as those developed in Monte Carlo simulations for risk analyses. We also illustrate how a sensitivity analysis can be conducted within a PBA by pinching inputs to precise distributions or real values

  9. From analysis to surface

    DEFF Research Database (Denmark)

    Bemman, Brian; Meredith, David

    it with a “ground truth” analysis of the same music pro- duced by a human expert (see, in particular, [5]). In this paper, we explore the problem of generating an encoding of the musical surface of a work automatically from a systematic encoding of an analysis. The ability to do this depends on one having...... an effective (i.e., comput- able), correct and complete description of some aspect of the structure of the music. Generating the surface struc- ture of a piece from an analysis in this manner serves as a proof of the analysis' correctness, effectiveness and com- pleteness. We present a reductive analysis......In recent years, a significant body of research has focused on developing algorithms for computing analyses of mu- sical works automatically from encodings of these works' surfaces [3,4,7,10,11]. The quality of the output of such analysis algorithms is typically evaluated by comparing...

  10. Sensitivity analysis in remote sensing

    CERN Document Server

    Ustinov, Eugene A

    2015-01-01

    This book contains a detailed presentation of general principles of sensitivity analysis as well as their applications to sample cases of remote sensing experiments. An emphasis is made on applications of adjoint problems, because they are more efficient in many practical cases, although their formulation may seem counterintuitive to a beginner. Special attention is paid to forward problems based on higher-order partial differential equations, where a novel matrix operator approach to formulation of corresponding adjoint problems is presented. Sensitivity analysis (SA) serves for quantitative models of physical objects the same purpose, as differential calculus does for functions. SA provides derivatives of model output parameters (observables) with respect to input parameters. In remote sensing SA provides computer-efficient means to compute the jacobians, matrices of partial derivatives of observables with respect to the geophysical parameters of interest. The jacobians are used to solve corresponding inver...

  11. Sensitivity of surface meteorological analyses to observation networks

    Science.gov (United States)

    Tyndall, Daniel Paul

    A computationally efficient variational analysis system for two-dimensional meteorological fields is developed and described. This analysis approach is most efficient when the number of analysis grid points is much larger than the number of available observations, such as for large domain mesoscale analyses. The analysis system is developed using MATLAB software and can take advantage of multiple processors or processor cores. A version of the analysis system has been exported as a platform independent application (i.e., can be run on Windows, Linux, or Macintosh OS X desktop computers without a MATLAB license) with input/output operations handled by commonly available internet software combined with data archives at the University of Utah. The impact of observation networks on the meteorological analyses is assessed by utilizing a percentile ranking of individual observation sensitivity and impact, which is computed by using the adjoint of the variational surface assimilation system. This methodology is demonstrated using a case study of the analysis from 1400 UTC 27 October 2010 over the entire contiguous United States domain. The sensitivity of this approach to the dependence of the background error covariance on observation density is examined. Observation sensitivity and impact provide insight on the influence of observations from heterogeneous observing networks as well as serve as objective metrics for quality control procedures that may help to identify stations with significant siting, reporting, or representativeness issues.

  12. Sensitivity Analysis of Viscoelastic Structures

    Directory of Open Access Journals (Sweden)

    A.M.G. de Lima

    2006-01-01

    Full Text Available In the context of control of sound and vibration of mechanical systems, the use of viscoelastic materials has been regarded as a convenient strategy in many types of industrial applications. Numerical models based on finite element discretization have been frequently used in the analysis and design of complex structural systems incorporating viscoelastic materials. Such models must account for the typical dependence of the viscoelastic characteristics on operational and environmental parameters, such as frequency and temperature. In many applications, including optimal design and model updating, sensitivity analysis based on numerical models is a very usefull tool. In this paper, the formulation of first-order sensitivity analysis of complex frequency response functions is developed for plates treated with passive constraining damping layers, considering geometrical characteristics, such as the thicknesses of the multi-layer components, as design variables. Also, the sensitivity of the frequency response functions with respect to temperature is introduced. As an example, response derivatives are calculated for a three-layer sandwich plate and the results obtained are compared with first-order finite-difference approximations.

  13. Self-assembled two-dimensional gold nanoparticle film for sensitive nontargeted analysis of food additives with surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Wu, Yiping; Yu, Wenfang; Yang, Benhong; Li, Pan

    2018-05-15

    The use of different food additives and their active metabolites has been found to cause serious problems to human health. Thus, considering the potential effects on human health, developing a sensitive and credible analytical method for different foods is important. Herein, the application of solvent-driven self-assembled Au nanoparticles (Au NPs) for the rapid and sensitive detection of food additives in different commercial products is reported. The assembled substrates are highly sensitive and exhibit excellent uniformity and reproducibility because of uniformly distributed and high-density hot spots. The sensitive analyses of ciprofloxacin (CF), diethylhexyl phthalate (DEHP), tartrazine and azodicarbonamide at the 0.1 ppm level using this surface-enhanced Raman spectroscopy (SERS) substrate are given, and the results show that Au NP arrays can serve as efficient SERS substrates for the detection of food additives. More importantly, SERS spectra of several commercial liquors and sweet drinks are obtained to evaluate the addition of illegal additives. This SERS active platform can be used as an effective strategy in the detection of prohibited additives in food.

  14. Land surface sensitivity of mesoscale convective systems

    Science.gov (United States)

    Tournay, Robert C.

    Mesoscale convective systems (MCSs) are important contributors to the hydrologic cycle in many regions of the world as well as major sources of severe weather. MCSs continue to challenge forecasters and researchers alike, arising from difficulties in understanding system initiation, propagation, and demise. One distinct type of MCS is that formed from individual convective cells initiated primarily by daytime heating over high terrain. This work is aimed at improving our understanding of the land surface sensitivity of this class of MCS in the contiguous United States. First, a climatology of mesoscale convective systems originating in the Rocky Mountains and adjacent high plains from Wyoming southward to New Mexico is developed through a combination of objective and subjective methods. This class of MCS is most important, in terms of total warm season precipitation, in the 500 to 1300m elevations of the Great Plains (GP) to the east in eastern Colorado to central Nebraska and northwest Kansas. Examining MCSs by longevity, short lasting MCSs (15 hrs) reveals that longer lasting systems tend to form further south and have a longer track with a more southerly track. The environment into which the MCS is moving showed differences across commonly used variables in convection forecasting, with some variables showing more favorable conditions throughout (convective inhibition, 0-6 km shear and 250 hPa wind speed) ahead of longer lasting MCSs. Other variables, such as convective available potential energy, showed improving conditions through time for longer lasting MCSs. Some variables showed no difference across longevity of MCS (precipitable water and large-scale vertical motion). From subsets of this MCS climatology, three regions of origin were chosen based on the presence of ridgelines extending eastward from the Rocky Mountains known to be foci for convection initiation and subsequent MCS formation: Southern Wyoming (Cheyenne Ridge), Colorado (Palmer divide) and

  15. Surface plasmon optics for biosensors with advanced sensitivity and throughput

    International Nuclear Information System (INIS)

    Toma, M.

    2012-01-01

    Plasmonic biosensors represent a rapidly advancing technology which enables rapid and sensitive analysis of target analytes. This thesis focuses on novel metallic and polymer structures for plasmonic biosensors based on surface plasmon resonance (SPR) and surface plasmon-enhanced fluorescence (SPF). It comprises four projects addressing key challenges concerning the enhancement of sensitivity and throughput. In the project 1, an advanced optical platform is developed which relies on reference-compensated angular spectroscopy of hydrogel-guided waves. The developed optical setup provides superior refractive index resolution of 1.2×10 -7 RIU and offers an attractive platform for direct detection of small analytes which cannot be analyzed by regular SPR biosensors. The project 2 carries out theoretical study of SPR imaging with advanced lateral resolution by utilizing Bragg scattered surface plasmons (BSSPs) on sub-wavelength metallic gratings. The results reveal that the proposed concept provides better lateral resolution and fidelity of the images. This feature opens ways for high-throughput SPR biosensors with denser arrays of sensing spots. The project 3 investigates surface plasmon coupled-emission from fluorophores in the vicinity of plasmonic Bragg-gratings. The experimental results provide leads on advancing the collection efficiency of fluorescence light by controlling the directions of fluorescence emission. This functionality can directly improve the sensitivity of fluorescence-based assays. In the last project 4, a novel sensing scheme with actively tuneable plasmonic structures is developed by employing thermo-responsive hydrogel binding matrix. The hydrogel film simultaneously serves as a large capacity binding matrix and provides means for actuating of surface plasmons through reversible swelling and collapsing of the hydrogel. This characteristic is suitable for multiplexing of sensing channels in fluorescence-based biosensor scheme (author)

  16. UMTS Common Channel Sensitivity Analysis

    DEFF Research Database (Denmark)

    Pratas, Nuno; Rodrigues, António; Santos, Frederico

    2006-01-01

    and as such it is necessary that both channels be available across the cell radius. This requirement makes the choice of the transmission parameters a fundamental one. This paper presents a sensitivity analysis regarding the transmission parameters of two UMTS common channels: RACH and FACH. Optimization of these channels...... is performed and values for the key transmission parameters in both common channels are obtained. On RACH these parameters are the message to preamble offset, the initial SIR target and the preamble power step while on FACH it is the transmission power offset....

  17. TEMAC, Top Event Sensitivity Analysis

    International Nuclear Information System (INIS)

    Iman, R.L.; Shortencarier, M.J.

    1988-01-01

    1 - Description of program or function: TEMAC is designed to permit the user to easily estimate risk and to perform sensitivity and uncertainty analyses with a Boolean expression such as produced by the SETS computer program. SETS produces a mathematical representation of a fault tree used to model system unavailability. In the terminology of the TEMAC program, such a mathematical representation is referred to as a top event. The analysis of risk involves the estimation of the magnitude of risk, the sensitivity of risk estimates to base event probabilities and initiating event frequencies, and the quantification of the uncertainty in the risk estimates. 2 - Method of solution: Sensitivity and uncertainty analyses associated with top events involve mathematical operations on the corresponding Boolean expression for the top event, as well as repeated evaluations of the top event in a Monte Carlo fashion. TEMAC employs a general matrix approach which provides a convenient general form for Boolean expressions, is computationally efficient, and allows large problems to be analyzed. 3 - Restrictions on the complexity of the problem - Maxima of: 4000 cut sets, 500 events, 500 values in a Monte Carlo sample, 16 characters in an event name. These restrictions are implemented through the FORTRAN 77 PARAMATER statement

  18. Gold Nanorods as Surface-Enhanced Raman Spectroscopy Substrates for Rapid and Sensitive Analysis of Allura Red and Sunset Yellow in Beverages.

    Science.gov (United States)

    Ou, Yiming; Wang, Xiaohui; Lai, Keqiang; Huang, Yiqun; Rasco, Barbara A; Fan, Yuxia

    2018-03-21

    Synthetic colorants in food can be a potential threat to human health. In this study, surface-enhanced Raman spectroscopy (SERS) coupled with gold nanorods as substrates is proposed to analyze allura red and sunset yellow in beverages. The gold nanorods with different aspect ratios were synthesized, and their long-term stability, SERS activity, and the effect of the different salts on the SERS signal were investigated. The results demonstrate that gold nanorods have a satisfactory stability (stored up to 28 days). SERS coupled with gold nanorods exhibit stronger sensitivity. MgSO 4 was chosen to improve the SERS signal of sunset yellow, and no salts could enhance the SERS signal of allura red. The lowest concentration was 0.10 mg/L for both colorant standard solutions. The successful prediction results using SERS were much closer to those obtained by high-performance liquid chromatography for the sample in beverages. SERS combined with gold nanorods shows potential for analyzing food colorants and other food additives as a rapid, convenient, and sensitive method.

  19. Data fusion qualitative sensitivity analysis

    International Nuclear Information System (INIS)

    Clayton, E.A.; Lewis, R.E.

    1995-09-01

    Pacific Northwest Laboratory was tasked with testing, debugging, and refining the Hanford Site data fusion workstation (DFW), with the assistance of Coleman Research Corporation (CRC), before delivering the DFW to the environmental restoration client at the Hanford Site. Data fusion is the mathematical combination (or fusion) of disparate data sets into a single interpretation. The data fusion software used in this study was developed by CRC. The data fusion software developed by CRC was initially demonstrated on a data set collected at the Hanford Site where three types of data were combined. These data were (1) seismic reflection, (2) seismic refraction, and (3) depth to geologic horizons. The fused results included a contour map of the top of a low-permeability horizon. This report discusses the results of a sensitivity analysis of data fusion software to variations in its input parameters. The data fusion software developed by CRC has a large number of input parameters that can be varied by the user and that influence the results of data fusion. Many of these parameters are defined as part of the earth model. The earth model is a series of 3-dimensional polynomials with horizontal spatial coordinates as the independent variables and either subsurface layer depth or values of various properties within these layers (e.g., compression wave velocity, resistivity) as the dependent variables

  20. Surface sensitivity of nuclear-knock-out form factors

    International Nuclear Information System (INIS)

    Fratamico, G.

    1984-01-01

    A numerical calculation has been performed to investigate the sensitivity of nuclear-knock-out form factors to nuclear-surface behaviour of bound-state wave functions. The result of our investigation suggests that one can extract the bound-state behaviour at the surface from experimental information on nuclear-knock-out form factors

  1. Probabilistic sensitivity analysis of biochemical reaction systems.

    Science.gov (United States)

    Zhang, Hong-Xuan; Dempsey, William P; Goutsias, John

    2009-09-07

    Sensitivity analysis is an indispensable tool for studying the robustness and fragility properties of biochemical reaction systems as well as for designing optimal approaches for selective perturbation and intervention. Deterministic sensitivity analysis techniques, using derivatives of the system response, have been extensively used in the literature. However, these techniques suffer from several drawbacks, which must be carefully considered before using them in problems of systems biology. We develop here a probabilistic approach to sensitivity analysis of biochemical reaction systems. The proposed technique employs a biophysically derived model for parameter fluctuations and, by using a recently suggested variance-based approach to sensitivity analysis [Saltelli et al., Chem. Rev. (Washington, D.C.) 105, 2811 (2005)], it leads to a powerful sensitivity analysis methodology for biochemical reaction systems. The approach presented in this paper addresses many problems associated with derivative-based sensitivity analysis techniques. Most importantly, it produces thermodynamically consistent sensitivity analysis results, can easily accommodate appreciable parameter variations, and allows for systematic investigation of high-order interaction effects. By employing a computational model of the mitogen-activated protein kinase signaling cascade, we demonstrate that our approach is well suited for sensitivity analysis of biochemical reaction systems and can produce a wealth of information about the sensitivity properties of such systems. The price to be paid, however, is a substantial increase in computational complexity over derivative-based techniques, which must be effectively addressed in order to make the proposed approach to sensitivity analysis more practical.

  2. Temperature sensitive surfaces and methods of making same

    Science.gov (United States)

    Liang, Liang [Richland, WA; Rieke, Peter C [Pasco, WA; Alford, Kentin L [Pasco, WA

    2002-09-10

    Poly-n-isopropylacrylamide surface coatings demonstrate the useful property of being able to switch charateristics depending upon temperature. More specifically, these coatings switch from being hydrophilic at low temperature to hydrophobic at high temperature. Research has been conducted for many years to better characterize and control the properties of temperature sensitive coatings. The present invention provides novel temperature sensitive coatings on articles and novel methods of making temperature sensitive coatings that are disposed on the surfaces of various articles. These novel coatings contain the reaction products of n-isopropylacrylamide and are characterized by their properties such as advancing contact angles. Numerous other characteristics such as coating thickness, surface roughness, and hydrophilic-to-hydrophobic transition temperatures are also described. The present invention includes articles having temperature-sensitve coatings with improved properties as well as improved methods for forming temperature sensitive coatings.

  3. Sensitivity Analysis of a Physiochemical Interaction Model ...

    African Journals Online (AJOL)

    In this analysis, we will study the sensitivity analysis due to a variation of the initial condition and experimental time. These results which we have not seen elsewhere are analysed and discussed quantitatively. Keywords: Passivation Rate, Sensitivity Analysis, ODE23, ODE45 J. Appl. Sci. Environ. Manage. June, 2012, Vol.

  4. Sensitivity Analysis of Multidisciplinary Rotorcraft Simulations

    Science.gov (United States)

    Wang, Li; Diskin, Boris; Biedron, Robert T.; Nielsen, Eric J.; Bauchau, Olivier A.

    2017-01-01

    A multidisciplinary sensitivity analysis of rotorcraft simulations involving tightly coupled high-fidelity computational fluid dynamics and comprehensive analysis solvers is presented and evaluated. An unstructured sensitivity-enabled Navier-Stokes solver, FUN3D, and a nonlinear flexible multibody dynamics solver, DYMORE, are coupled to predict the aerodynamic loads and structural responses of helicopter rotor blades. A discretely-consistent adjoint-based sensitivity analysis available in FUN3D provides sensitivities arising from unsteady turbulent flows and unstructured dynamic overset meshes, while a complex-variable approach is used to compute DYMORE structural sensitivities with respect to aerodynamic loads. The multidisciplinary sensitivity analysis is conducted through integrating the sensitivity components from each discipline of the coupled system. Numerical results verify accuracy of the FUN3D/DYMORE system by conducting simulations for a benchmark rotorcraft test model and comparing solutions with established analyses and experimental data. Complex-variable implementation of sensitivity analysis of DYMORE and the coupled FUN3D/DYMORE system is verified by comparing with real-valued analysis and sensitivities. Correctness of adjoint formulations for FUN3D/DYMORE interfaces is verified by comparing adjoint-based and complex-variable sensitivities. Finally, sensitivities of the lift and drag functions obtained by complex-variable FUN3D/DYMORE simulations are compared with sensitivities computed by the multidisciplinary sensitivity analysis, which couples adjoint-based flow and grid sensitivities of FUN3D and FUN3D/DYMORE interfaces with complex-variable sensitivities of DYMORE structural responses.

  5. Surface science study of selective ethylene epoxidation catalyzed by the Ag(110) surface: Structural sensitivity

    International Nuclear Information System (INIS)

    Campbell, C.T.

    1984-01-01

    The selective oxidation of ethylene to ethylene epoxide (C 2 H 4 +1/2O 2 →C 2 H 4 O) over Ag is the simplest example of kinetically controlled, selective heterogeneous catalysis. We have studied the steady-state kinetics and selectivity of this reaction for the first time on a clean, well-characterized Ag(110) surface by using a special apparatus which allows rapid (approx.20 s) transfer between a high-pressure catalytic microreactor and an ultrahigh vacuum surface analysis (AES, XPS, LEED, TDS) chamber. The effects of temperature and reactant pressures upon the rate and selectivity are virtually identical on Ag(110) and supported, high surface area Ag catalysts. The absolute specific rate (per Ag surface atom) is, however, some 100-fold higher for Ag(110) than for high surface area catalysts. This is related to the well-known structural sensitivity of this reaction. It is postulated that a small percentage of (110) planes (or [110]-like sites) are responsible for most of the catalytic activity of high surface area catalysts. The high activity of the (110) plane is attributed to its high sticking probability for dissociative oxygen adsorption, since the rate of ethylene epoxidation is shown in a related work [Ref. 1: C. T. Campbell and M. T. Paffett, Surf. Sci. (in press)] to be proportional to the coverage of atomically adsorbed oxygen at constant temperature and ethylene pressure

  6. Risk Characterization uncertainties associated description, sensitivity analysis

    International Nuclear Information System (INIS)

    Carrillo, M.; Tovar, M.; Alvarez, J.; Arraez, M.; Hordziejewicz, I.; Loreto, I.

    2013-01-01

    The power point presentation is about risks to the estimated levels of exposure, uncertainty and variability in the analysis, sensitivity analysis, risks from exposure to multiple substances, formulation of guidelines for carcinogenic and genotoxic compounds and risk subpopulations

  7. Object-sensitive Type Analysis of PHP

    NARCIS (Netherlands)

    Van der Hoek, Henk Erik; Hage, J

    2015-01-01

    In this paper we develop an object-sensitive type analysis for PHP, based on an extension of the notion of monotone frameworks to deal with the dynamic aspects of PHP, and following the framework of Smaragdakis et al. for object-sensitive analysis. We consider a number of instantiations of the

  8. Sensitivity of point scale surface runoff predictions to rainfall resolution

    Directory of Open Access Journals (Sweden)

    A. J. Hearman

    2007-01-01

    averaged rainfall under these soil and rainfall conditions and predictions of larger scale phenomena such as hillslope runoff and runon. It offers insight into how rainfall resolution can affect predicted amounts of water entering the soil and thus soil water storage and drainage, possibly changing our understanding of the ecological functioning of the system or predictions of agri-chemical leaching. The application of this sensitivity analysis to different rainfall regions in Western Australia showed that locations in the tropics with higher intensity rainfalls are more likely to have differences in infiltration excess predictions with different rainfall resolutions and that a general understanding of the prevailing rainfall conditions and the soil's infiltration capacity can help in deciding whether high rainfall resolutions (below 1 h are required for accurate surface runoff predictions.

  9. A hybrid approach for global sensitivity analysis

    International Nuclear Information System (INIS)

    Chakraborty, Souvik; Chowdhury, Rajib

    2017-01-01

    Distribution based sensitivity analysis (DSA) computes sensitivity of the input random variables with respect to the change in distribution of output response. Although DSA is widely appreciated as the best tool for sensitivity analysis, the computational issue associated with this method prohibits its use for complex structures involving costly finite element analysis. For addressing this issue, this paper presents a method that couples polynomial correlated function expansion (PCFE) with DSA. PCFE is a fully equivalent operational model which integrates the concepts of analysis of variance decomposition, extended bases and homotopy algorithm. By integrating PCFE into DSA, it is possible to considerably alleviate the computational burden. Three examples are presented to demonstrate the performance of the proposed approach for sensitivity analysis. For all the problems, proposed approach yields excellent results with significantly reduced computational effort. The results obtained, to some extent, indicate that proposed approach can be utilized for sensitivity analysis of large scale structures. - Highlights: • A hybrid approach for global sensitivity analysis is proposed. • Proposed approach integrates PCFE within distribution based sensitivity analysis. • Proposed approach is highly efficient.

  10. Sensitivity analysis of a PWR pressurizer

    International Nuclear Information System (INIS)

    Bruel, Renata Nunes

    1997-01-01

    A sensitivity analysis relative to the parameters and modelling of the physical process in a PWR pressurizer has been performed. The sensitivity analysis was developed by implementing the key parameters and theoretical model lings which generated a comprehensive matrix of influences of each changes analysed. The major influences that have been observed were the flashing phenomenon and the steam condensation on the spray drops. The present analysis is also applicable to the several theoretical and experimental areas. (author)

  11. Sensitivity analysis for large-scale problems

    Science.gov (United States)

    Noor, Ahmed K.; Whitworth, Sandra L.

    1987-01-01

    The development of efficient techniques for calculating sensitivity derivatives is studied. The objective is to present a computational procedure for calculating sensitivity derivatives as part of performing structural reanalysis for large-scale problems. The scope is limited to framed type structures. Both linear static analysis and free-vibration eigenvalue problems are considered.

  12. Sensitivity analysis in life cycle assessment

    NARCIS (Netherlands)

    Groen, E.A.; Heijungs, R.; Bokkers, E.A.M.; Boer, de I.J.M.

    2014-01-01

    Life cycle assessments require many input parameters and many of these parameters are uncertain; therefore, a sensitivity analysis is an essential part of the final interpretation. The aim of this study is to compare seven sensitivity methods applied to three types of case stud-ies. Two

  13. Ethical sensitivity in professional practice: concept analysis.

    Science.gov (United States)

    Weaver, Kathryn; Morse, Janice; Mitcham, Carl

    2008-06-01

    This paper is a report of a concept analysis of ethical sensitivity. Ethical sensitivity enables nurses and other professionals to respond morally to the suffering and vulnerability of those receiving professional care and services. Because of its significance to nursing and other professional practices, ethical sensitivity deserves more focused analysis. A criteria-based method oriented toward pragmatic utility guided the analysis of 200 papers and books from the fields of nursing, medicine, psychology, dentistry, clinical ethics, theology, education, law, accounting or business, journalism, philosophy, political and social sciences and women's studies. This literature spanned 1970 to 2006 and was sorted by discipline and concept dimensions and examined for concept structure and use across various contexts. The analysis was completed in September 2007. Ethical sensitivity in professional practice develops in contexts of uncertainty, client suffering and vulnerability, and through relationships characterized by receptivity, responsiveness and courage on the part of professionals. Essential attributes of ethical sensitivity are identified as moral perception, affectivity and dividing loyalties. Outcomes include integrity preserving decision-making, comfort and well-being, learning and professional transcendence. Our findings promote ethical sensitivity as a type of practical wisdom that pursues client comfort and professional satisfaction with care delivery. The analysis and resulting model offers an inclusive view of ethical sensitivity that addresses some of the limitations with prior conceptualizations.

  14. LBLOCA sensitivity analysis using meta models

    International Nuclear Information System (INIS)

    Villamizar, M.; Sanchez-Saez, F.; Villanueva, J.F.; Carlos, S.; Sanchez, A.I.; Martorell, S.

    2014-01-01

    This paper presents an approach to perform the sensitivity analysis of the results of simulation of thermal hydraulic codes within a BEPU approach. Sensitivity analysis is based on the computation of Sobol' indices that makes use of a meta model, It presents also an application to a Large-Break Loss of Coolant Accident, LBLOCA, in the cold leg of a pressurized water reactor, PWR, addressing the results of the BEMUSE program and using the thermal-hydraulic code TRACE. (authors)

  15. Sensitivity analysis in optimization and reliability problems

    International Nuclear Information System (INIS)

    Castillo, Enrique; Minguez, Roberto; Castillo, Carmen

    2008-01-01

    The paper starts giving the main results that allow a sensitivity analysis to be performed in a general optimization problem, including sensitivities of the objective function, the primal and the dual variables with respect to data. In particular, general results are given for non-linear programming, and closed formulas for linear programming problems are supplied. Next, the methods are applied to a collection of civil engineering reliability problems, which includes a bridge crane, a retaining wall and a composite breakwater. Finally, the sensitivity analysis formulas are extended to calculus of variations problems and a slope stability problem is used to illustrate the methods

  16. Sensitivity analysis in optimization and reliability problems

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Enrique [Department of Applied Mathematics and Computational Sciences, University of Cantabria, Avda. Castros s/n., 39005 Santander (Spain)], E-mail: castie@unican.es; Minguez, Roberto [Department of Applied Mathematics, University of Castilla-La Mancha, 13071 Ciudad Real (Spain)], E-mail: roberto.minguez@uclm.es; Castillo, Carmen [Department of Civil Engineering, University of Castilla-La Mancha, 13071 Ciudad Real (Spain)], E-mail: mariacarmen.castillo@uclm.es

    2008-12-15

    The paper starts giving the main results that allow a sensitivity analysis to be performed in a general optimization problem, including sensitivities of the objective function, the primal and the dual variables with respect to data. In particular, general results are given for non-linear programming, and closed formulas for linear programming problems are supplied. Next, the methods are applied to a collection of civil engineering reliability problems, which includes a bridge crane, a retaining wall and a composite breakwater. Finally, the sensitivity analysis formulas are extended to calculus of variations problems and a slope stability problem is used to illustrate the methods.

  17. Techniques for sensitivity analysis of SYVAC results

    International Nuclear Information System (INIS)

    Prust, J.O.

    1985-05-01

    Sensitivity analysis techniques may be required to examine the sensitivity of SYVAC model predictions to the input parameter values, the subjective probability distributions assigned to the input parameters and to the relationship between dose and the probability of fatal cancers plus serious hereditary disease in the first two generations of offspring of a member of the critical group. This report mainly considers techniques for determining the sensitivity of dose and risk to the variable input parameters. The performance of a sensitivity analysis technique may be improved by decomposing the model and data into subsets for analysis, making use of existing information on sensitivity and concentrating sampling in regions the parameter space that generates high doses or risks. A number of sensitivity analysis techniques are reviewed for their application to the SYVAC model including four techniques tested in an earlier study by CAP Scientific for the SYVAC project. This report recommends the development now of a method for evaluating the derivative of dose and parameter value and extending the Kruskal-Wallis technique to test for interactions between parameters. It is also recommended that the sensitivity of the output of each sub-model of SYVAC to input parameter values should be examined. (author)

  18. Analysis of hepatitis B surface antigen (HBsAg) using high-sensitivity HBsAg assays in hepatitis B virus carriers in whom HBsAg seroclearance was confirmed by conventional assays.

    Science.gov (United States)

    Ozeki, Itaru; Nakajima, Tomoaki; Suii, Hirokazu; Tatsumi, Ryoji; Yamaguchi, Masakatsu; Kimura, Mutsuumi; Arakawa, Tomohiro; Kuwata, Yasuaki; Ohmura, Takumi; Hige, Shuhei; Karino, Yoshiyasu; Toyota, Joji

    2018-02-01

    We investigated the utility of high-sensitivity hepatitis B surface antigen (HBsAg) assays compared with conventional HBsAg assays. Using serum samples from 114 hepatitis B virus (HBV) carriers in whom HBsAg seroclearance was confirmed by conventional HBsAg assays (cut-off value, 0.05 IU/mL), the amount of HBsAg was re-examined by high-sensitivity HBsAg assays (cut-off value, 0.005 IU/mL). Cases negative for HBsAg in both assays were defined as consistent cases, and cases positive for HBsAg in the high-sensitivity HBsAg assay only were defined as discrepant cases. There were 55 (48.2%) discrepant cases, and the range of HBsAg titers determined by high-sensitivity HBsAg assays was 0.005-0.056 IU/mL. Multivariate analysis showed that the presence of nucleos(t)ide analog therapy, liver cirrhosis, and negative anti-HBs contributed to the discrepancies between the two assays. Cumulative anti-HBs positivity rates among discrepant cases were 12.7%, 17.2%, 38.8%, and 43.9% at baseline, 1 year, 3 years, and 5 years, respectively, whereas the corresponding rates among consistent cases were 50.8%, 56.0%, 61.7%, and 68.0%, respectively. Hepatitis B virus DNA negativity rates were 56.4% and 81.4% at baseline, 51.3% and 83.3% at 1 year, and 36.8% and 95.7% at 3 years, among discrepant and consistent cases, respectively. Hepatitis B surface antigen reversion was observed only in discrepant cases. Re-examination by high-sensitivity HBsAg assays revealed that HBsAg was positive in approximately 50% of cases. Cumulative anti-HBs seroconversion rates and HBV-DNA seroclearance rates were lower in these cases, suggesting a population at risk for HBsAg reversion. © 2017 The Japan Society of Hepatology.

  19. Multiple predictor smoothing methods for sensitivity analysis

    International Nuclear Information System (INIS)

    Helton, Jon Craig; Storlie, Curtis B.

    2006-01-01

    The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (1) locally weighted regression (LOESS), (2) additive models, (3) projection pursuit regression, and (4) recursive partitioning regression. The indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present

  20. Multiple predictor smoothing methods for sensitivity analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Helton, Jon Craig; Storlie, Curtis B.

    2006-08-01

    The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (1) locally weighted regression (LOESS), (2) additive models, (3) projection pursuit regression, and (4) recursive partitioning regression. The indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present.

  1. Surface analysis the principal techniques

    CERN Document Server

    Vickerman, John C

    2009-01-01

    This completely updated and revised second edition of Surface Analysis: The Principal Techniques, deals with the characterisation and understanding of the outer layers of substrates, how they react, look and function which are all of interest to surface scientists. Within this comprehensive text, experts in each analysis area introduce the theory and practice of the principal techniques that have shown themselves to be effective in both basic research and in applied surface analysis. Examples of analysis are provided to facilitate the understanding of this topic and to show readers how they c

  2. Sensitivity Analysis of Criticality for Different Nuclear Fuel Shapes

    International Nuclear Information System (INIS)

    Kang, Hyun Sik; Jang, Misuk; Kim, Seoung Rae

    2016-01-01

    Rod-type nuclear fuel was mainly developed in the past, but recent study has been extended to plate-type nuclear fuel. Therefore, this paper reviews the sensitivity of criticality according to different shapes of nuclear fuel types. Criticality analysis was performed using MCNP5. MCNP5 is well-known Monte Carlo codes for criticality analysis and a general-purpose Monte Carlo N-Particle code that can be used for neutron, photon, electron or coupled neutron / photon / electron transport, including the capability to calculate eigenvalues for critical systems. We performed the sensitivity analysis of criticality for different fuel shapes. In sensitivity analysis for simple fuel shapes, the criticality is proportional to the surface area. But for fuel Assembly types, it is not proportional to the surface area. In sensitivity analysis for intervals between plates, the criticality is greater as the interval increases, but if the interval is greater than 8mm, it showed an opposite trend that the criticality decrease by a larger interval. As a result, it has failed to obtain the logical content to be described in common for all cases. The sensitivity analysis of Criticality would be always required whenever subject to be analyzed is changed

  3. Sensitivity Analysis of Criticality for Different Nuclear Fuel Shapes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyun Sik; Jang, Misuk; Kim, Seoung Rae [NESS, Daejeon (Korea, Republic of)

    2016-10-15

    Rod-type nuclear fuel was mainly developed in the past, but recent study has been extended to plate-type nuclear fuel. Therefore, this paper reviews the sensitivity of criticality according to different shapes of nuclear fuel types. Criticality analysis was performed using MCNP5. MCNP5 is well-known Monte Carlo codes for criticality analysis and a general-purpose Monte Carlo N-Particle code that can be used for neutron, photon, electron or coupled neutron / photon / electron transport, including the capability to calculate eigenvalues for critical systems. We performed the sensitivity analysis of criticality for different fuel shapes. In sensitivity analysis for simple fuel shapes, the criticality is proportional to the surface area. But for fuel Assembly types, it is not proportional to the surface area. In sensitivity analysis for intervals between plates, the criticality is greater as the interval increases, but if the interval is greater than 8mm, it showed an opposite trend that the criticality decrease by a larger interval. As a result, it has failed to obtain the logical content to be described in common for all cases. The sensitivity analysis of Criticality would be always required whenever subject to be analyzed is changed.

  4. Non-spectroscopic surface plasmon sensor with a tunable sensitivity

    International Nuclear Information System (INIS)

    Wen, Qiuling; Han, Xu; Hu, Chuang; Zhang, Jiasen

    2015-01-01

    We demonstrate a non-spectroscopic surface plasmon sensor with a tunable sensitivity which is based on the relationship between the wave number of surface plasmon polaritons (SPPs) on metal film and the refractive index of the specimen in contact with the metal film. A change in the wave number of the SPPs results in a variation in the propagation angle of the leakage radiation of the SPPs. A reference light is used to interfere with the leakage radiation, and the refractive index of the specimen can be obtained by measuring the period of the interference fringes. The sensitivity of the sensor can be tuned by changing the incident direction of the reference light and this cannot be realized by conventional surface plasmon sensors. For a reference angle of 1.007°, the sensitivity and resolution of the sensor are 4629 μm/RIU (RIU stands for refractive index unit) and 3.6 × 10 −4 RIU, respectively. In addition, the sensor only needs a monochromatic light source, which simplifies the measurement setup and reduces the cost

  5. Dynamic Resonance Sensitivity Analysis in Wind Farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2017-01-01

    (PFs) are calculated by critical eigenvalue sensitivity analysis versus the entries of the MIMO matrix. The PF analysis locates the most exciting bus of the resonances, where can be the best location to install the passive or active filters to reduce the harmonic resonance problems. Time...

  6. THE EFFECT OF BONDING AND SURFACE SEALANT APPLICATION ON POSTOPERATIVE SENSITIVITY FROM POSTERIOR COMPOSITES

    Directory of Open Access Journals (Sweden)

    Neslihan TEKÇE

    2015-10-01

    Full Text Available Purpose: The purpose of the study was to evaluate the postoperative sensitivity of posterior Class I composite restoration at short-term, restorated with two different all-in-one self-etch adhesives with or without surface sealant application. Materials and Methods: 44 restorations were inserted in 11 patients who required Class I restorations in their molars. Each patient received 4 restorations, thus four groups were formed; (1 G-Aenial Bond (GC, Japan; (2 Clearfil S3 Bond (Kuraray, Japan; (3 G-Aenial Bond+Fortify Plus (Bisco, USA, (4 Clearfil S3 Bond+Fortify Plus. Sensitivity was evaluated at 24h, 7, 15, and 30 days using cold air, ice, and pressure stimuli using a visual analog scale. Comparisons of continuous variables between the sensitivity evaluations were performed using the Friedman’s One-Way Analysis of Variance with repeated measures test (p0.05. The use of Clearfil S3 Bond resulted in almost the same level of postoperative sensitivity as did the use of G-Aenial Bond. The highest sensitivity scores were observed for the surface sealant applied teeth without any statistical significance (p>0.05. Conclusions: Self etch adhesives displayed postoperative sensitivity. The sensitivity scores slightly decreased at the end of 30 days (p>0.05. Surface sealant application did not result in a decrease in sensitivity scores for either dentin adhesives.

  7. Surface Temperature Data Analysis

    Science.gov (United States)

    Hansen, James; Ruedy, Reto

    2012-01-01

    Small global mean temperature changes may have significant to disastrous consequences for the Earth's climate if they persist for an extended period. Obtaining global means from local weather reports is hampered by the uneven spatial distribution of the reliably reporting weather stations. Methods had to be developed that minimize as far as possible the impact of that situation. This software is a method of combining temperature data of individual stations to obtain a global mean trend, overcoming/estimating the uncertainty introduced by the spatial and temporal gaps in the available data. Useful estimates were obtained by the introduction of a special grid, subdividing the Earth's surface into 8,000 equal-area boxes, using the existing data to create virtual stations at the center of each of these boxes, and combining temperature anomalies (after assessing the radius of high correlation) rather than temperatures.

  8. Sensitivity functions for uncertainty analysis: Sensitivity and uncertainty analysis of reactor performance parameters

    International Nuclear Information System (INIS)

    Greenspan, E.

    1982-01-01

    This chapter presents the mathematical basis for sensitivity functions, discusses their physical meaning and information they contain, and clarifies a number of issues concerning their application, including the definition of group sensitivities, the selection of sensitivity functions to be included in the analysis, and limitations of sensitivity theory. Examines the theoretical foundation; criticality reset sensitivities; group sensitivities and uncertainties; selection of sensitivities included in the analysis; and other uses and limitations of sensitivity functions. Gives the theoretical formulation of sensitivity functions pertaining to ''as-built'' designs for performance parameters of the form of ratios of linear flux functionals (such as reaction-rate ratios), linear adjoint functionals, bilinear functions (such as reactivity worth ratios), and for reactor reactivity. Offers a consistent procedure for reducing energy-dependent or fine-group sensitivities and uncertainties to broad group sensitivities and uncertainties. Provides illustrations of sensitivity functions as well as references to available compilations of such functions and of total sensitivities. Indicates limitations of sensitivity theory originating from the fact that this theory is based on a first-order perturbation theory

  9. Thin film surface reconstruction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Imperatori, P [CNR, Monterotondo Stazione, Rome (Italy). Istituto di Chimica dei materiali

    1996-09-01

    The study of the atomic structure of surfaces and interfaces is a fundamental step in the knowledge and the development of new materials. Among the several surface-sensitive techniques employed to characterise the atomic arrangements, grazing incidence x-ray diffraction (GIXD) is one of the most powerful. With a simple data treatment, based on the kinematical theory, and using the classical methods of x-ray bulk structure determination, it gives the atomic positions of atoms at a surface or an interface and the atomic displacements of subsurface layers for a complete determination of the structure. In this paper the main features of the technique will be briefly reviewed and selected of application to semiconductor and metal surfaces will be discussed.

  10. Probabilistic sensitivity analysis in health economics.

    Science.gov (United States)

    Baio, Gianluca; Dawid, A Philip

    2015-12-01

    Health economic evaluations have recently become an important part of the clinical and medical research process and have built upon more advanced statistical decision-theoretic foundations. In some contexts, it is officially required that uncertainty about both parameters and observable variables be properly taken into account, increasingly often by means of Bayesian methods. Among these, probabilistic sensitivity analysis has assumed a predominant role. The objective of this article is to review the problem of health economic assessment from the standpoint of Bayesian statistical decision theory with particular attention to the philosophy underlying the procedures for sensitivity analysis. © The Author(s) 2011.

  11. TOLERANCE SENSITIVITY ANALYSIS: THIRTY YEARS LATER

    Directory of Open Access Journals (Sweden)

    Richard E. Wendell

    2010-12-01

    Full Text Available Tolerance sensitivity analysis was conceived in 1980 as a pragmatic approach to effectively characterize a parametric region over which objective function coefficients and right-hand-side terms in linear programming could vary simultaneously and independently while maintaining the same optimal basis. As originally proposed, the tolerance region corresponds to the maximum percentage by which coefficients or terms could vary from their estimated values. Over the last thirty years the original results have been extended in a number of ways and applied in a variety of applications. This paper is a critical review of tolerance sensitivity analysis, including extensions and applications.

  12. A new surface resistance measurement method with ultrahigh sensitivity

    International Nuclear Information System (INIS)

    Liang, Changnian.

    1993-01-01

    A superconducting niobium triaxial cavity has been designed and fabricated to study residual surface resistance of planar superconducting materials. The edge of a 25.4 mm or larger diameter sample in the triaxial cavity is located outside the strong field region. Therefore, the edge effects and possible losses between the thin film and the substrate have been minimized, ensuring that induced RF losses are intrinsic to the test material. The fundamental resonant frequency of the cavity is the same as the working frequency of CEBAF cavities. The cavity has a compact size compared to its TE 011 counterpart, which makes it more sensitive to the sample's loss. For even higher sensitivity, a calorimetry method has been used to measure the RF losses on the superconducting sample. At 2 K, a 2 μK temperature change can be resolved by using carbon resistor sensors. The temperature distribution caused by RF heating is measured by 16 carbon composition resistor sensors. A 0.05 μW heating power can be detected as such a resolution, which translates to a surface resistance of 0.02 nΩ at a surface magnetic field of 52 Oe. This is the most sensitive device for surface resistance measurements to date. In addition, losses due to the indium seal, coupling probes, field emission sites other than the sample, and all of the high field resonator surface, are excluded in the measurement. Surface resistance of both niobium and high-Tc superconducting thin films has been measured. A low R s of 35.2 μΩ was measured for a 25.4 mm diameter YBa 2 Cu 3 O 7 thin film at 1.5 GHz and at 2 K. The measurement result is the first result for a large area epitaxially grown thin film sample at such a low RF frequency. The abrupt disappearance of multipacting between two parallel plates has been observed and monitored with the 16 temperature mapping sensors. Field emission or some field dependent anomalous RF losses on the niobium plate have also been observed

  13. Highly sensitive BTX detection using surface functionalized QCM sensor

    Energy Technology Data Exchange (ETDEWEB)

    Bozkurt, Asuman Aşıkoğlu; Özdemir, Okan; Altındal, Ahmet, E-mail: altindal@yildiz.edu.tr [Department of Physics, Yildiz Technical University, Davutpasa, 34210 Istanbul (Turkey)

    2016-03-25

    A novel organic compound was designed and successfully synthesized for the fabrication of QCM based sensors to detect the low concentrations of BTX gases in indoor air. The effect of the long-range electron orbital delocalization on the BTX vapour sensing properties of azo-bridged Pcs based chemiresistor-type sensors have also been investigated in this work. The sensing behaviour of the film for the online detection of volatile organic solvent vapors was investigated by utilizing an AT-cut quartz crystal resonator. It was observed that the adsorption of the target molecules on the coating surface cause a reversible negative frequency shift of the resonator. Thus, a variety of solvent vapors can be detected by using the phthalocyanine film as sensitive coating, with sensitivity in the ppm range and response times in the order of several seconds depending on the molecular structure of the organic solvent.

  14. Surface Sensitive Bolometer for the CUORE background reduction

    International Nuclear Information System (INIS)

    Pedretti, M.; Foggetta, L.; Giuliani, A.; Nones, C.; Sangiorgio, S.

    2005-01-01

    The most critical point of the CUORE Project [CUORE Proposal, see the web page: http://crio.mib.infn.it/wig] is the background level (BKGL) in the neutrinoless double beta decay (0νββ) region that is dominated by degraded particles coming from materials that face the detectors. Surface Sensitive Bolometers (SSBs) have been developed in order to reduce the BKGL by means of an active background discrimination. The principle of this technique and the first results obtained are briefly described in the following paper

  15. Sensitivity analysis technique for application to deterministic models

    International Nuclear Information System (INIS)

    Ishigami, T.; Cazzoli, E.; Khatib-Rahbar, M.; Unwin, S.D.

    1987-01-01

    The characterization of sever accident source terms for light water reactors should include consideration of uncertainties. An important element of any uncertainty analysis is an evaluation of the sensitivity of the output probability distributions reflecting source term uncertainties to assumptions regarding the input probability distributions. Historically, response surface methods (RSMs) were developed to replace physical models using, for example, regression techniques, with simplified models for example, regression techniques, with simplified models for extensive calculations. The purpose of this paper is to present a new method for sensitivity analysis that does not utilize RSM, but instead relies directly on the results obtained from the original computer code calculations. The merits of this approach are demonstrated by application of the proposed method to the suppression pool aerosol removal code (SPARC), and the results are compared with those obtained by sensitivity analysis with (a) the code itself, (b) a regression model, and (c) Iman's method

  16. Probabilistic Sensitivities for Fatigue Analysis of Turbine Engine Disks

    Directory of Open Access Journals (Sweden)

    Harry R. Millwater

    2006-01-01

    Full Text Available A methodology is developed and applied that determines the sensitivities of the probability-of-fracture of a gas turbine disk fatigue analysis with respect to the parameters of the probability distributions describing the random variables. The disk material is subject to initial anomalies, in either low- or high-frequency quantities, such that commonly used materials (titanium, nickel, powder nickel and common damage mechanisms (inherent defects or surface damage can be considered. The derivation is developed for Monte Carlo sampling such that the existing failure samples are used and the sensitivities are obtained with minimal additional computational time. Variance estimates and confidence bounds of the sensitivity estimates are developed. The methodology is demonstrated and verified using a multizone probabilistic fatigue analysis of a gas turbine compressor disk analysis considering stress scatter, crack growth propagation scatter, and initial crack size as random variables.

  17. Sensitivity Analysis of Centralized Dynamic Cell Selection

    DEFF Research Database (Denmark)

    Lopez, Victor Fernandez; Alvarez, Beatriz Soret; Pedersen, Klaus I.

    2016-01-01

    and a suboptimal optimization algorithm that nearly achieves the performance of the optimal Hungarian assignment. Moreover, an exhaustive sensitivity analysis with different network and traffic configurations is carried out in order to understand what conditions are more appropriate for the use of the proposed...

  18. Sensitivity analysis in a structural reliability context

    International Nuclear Information System (INIS)

    Lemaitre, Paul

    2014-01-01

    This thesis' subject is sensitivity analysis in a structural reliability context. The general framework is the study of a deterministic numerical model that allows to reproduce a complex physical phenomenon. The aim of a reliability study is to estimate the failure probability of the system from the numerical model and the uncertainties of the inputs. In this context, the quantification of the impact of the uncertainty of each input parameter on the output might be of interest. This step is called sensitivity analysis. Many scientific works deal with this topic but not in the reliability scope. This thesis' aim is to test existing sensitivity analysis methods, and to propose more efficient original methods. A bibliographical step on sensitivity analysis on one hand and on the estimation of small failure probabilities on the other hand is first proposed. This step raises the need to develop appropriate techniques. Two variables ranking methods are then explored. The first one proposes to make use of binary classifiers (random forests). The second one measures the departure, at each step of a subset method, between each input original density and the density given the subset reached. A more general and original methodology reflecting the impact of the input density modification on the failure probability is then explored. The proposed methods are then applied on the CWNR case, which motivates this thesis. (author)

  19. Applications of advances in nonlinear sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Werbos, P J

    1982-01-01

    The following paper summarizes the major properties and applications of a collection of algorithms involving differentiation and optimization at minimum cost. The areas of application include the sensitivity analysis of models, new work in statistical or econometric estimation, optimization, artificial intelligence and neuron modelling.

  20. *Corresponding Author Sensitivity Analysis of a Physiochemical ...

    African Journals Online (AJOL)

    Michael Horsfall

    The numerical method of sensitivity or the principle of parsimony ... analysis is a widely applied numerical method often being used in the .... Chemical Engineering Journal 128(2-3), 85-93. Amod S ... coupled 3-PG and soil organic matter.

  1. Sensitivity of surface radiation budget to clouds over the Asian ...

    Indian Academy of Sciences (India)

    National Climate Centre, India Meteorological Department, Pune 400 005. ... down on the earth surface–atmosphere system also as an imbalance between surface netcloud ... the clouds produce more cooling effect in short-wave band than the warming effect in long-wave .... In the present study, we use the analysis method.

  2. Sensitivity Analysis in Two-Stage DEA

    Directory of Open Access Journals (Sweden)

    Athena Forghani

    2015-07-01

    Full Text Available Data envelopment analysis (DEA is a method for measuring the efficiency of peer decision making units (DMUs which uses a set of inputs to produce a set of outputs. In some cases, DMUs have a two-stage structure, in which the first stage utilizes inputs to produce outputs used as the inputs of the second stage to produce final outputs. One important issue in two-stage DEA is the sensitivity of the results of an analysis to perturbations in the data. The current paper looks into combined model for two-stage DEA and applies the sensitivity analysis to DMUs on the entire frontier. In fact, necessary and sufficient conditions for preserving a DMU's efficiency classiffication are developed when various data changes are applied to all DMUs.

  3. Sensitivity Analysis in Two-Stage DEA

    Directory of Open Access Journals (Sweden)

    Athena Forghani

    2015-12-01

    Full Text Available Data envelopment analysis (DEA is a method for measuring the efficiency of peer decision making units (DMUs which uses a set of inputs to produce a set of outputs. In some cases, DMUs have a two-stage structure, in which the first stage utilizes inputs to produce outputs used as the inputs of the second stage to produce final outputs. One important issue in two-stage DEA is the sensitivity of the results of an analysis to perturbations in the data. The current paper looks into combined model for two-stage DEA and applies the sensitivity analysis to DMUs on the entire frontier. In fact, necessary and sufficient conditions for preserving a DMU's efficiency classiffication are developed when various data changes are applied to all DMUs.

  4. Sensitivity analysis and related analysis : A survey of statistical techniques

    NARCIS (Netherlands)

    Kleijnen, J.P.C.

    1995-01-01

    This paper reviews the state of the art in five related types of analysis, namely (i) sensitivity or what-if analysis, (ii) uncertainty or risk analysis, (iii) screening, (iv) validation, and (v) optimization. The main question is: when should which type of analysis be applied; which statistical

  5. Sensitivity Analysis in Sequential Decision Models.

    Science.gov (United States)

    Chen, Qiushi; Ayer, Turgay; Chhatwal, Jagpreet

    2017-02-01

    Sequential decision problems are frequently encountered in medical decision making, which are commonly solved using Markov decision processes (MDPs). Modeling guidelines recommend conducting sensitivity analyses in decision-analytic models to assess the robustness of the model results against the uncertainty in model parameters. However, standard methods of conducting sensitivity analyses cannot be directly applied to sequential decision problems because this would require evaluating all possible decision sequences, typically in the order of trillions, which is not practically feasible. As a result, most MDP-based modeling studies do not examine confidence in their recommended policies. In this study, we provide an approach to estimate uncertainty and confidence in the results of sequential decision models. First, we provide a probabilistic univariate method to identify the most sensitive parameters in MDPs. Second, we present a probabilistic multivariate approach to estimate the overall confidence in the recommended optimal policy considering joint uncertainty in the model parameters. We provide a graphical representation, which we call a policy acceptability curve, to summarize the confidence in the optimal policy by incorporating stakeholders' willingness to accept the base case policy. For a cost-effectiveness analysis, we provide an approach to construct a cost-effectiveness acceptability frontier, which shows the most cost-effective policy as well as the confidence in that for a given willingness to pay threshold. We demonstrate our approach using a simple MDP case study. We developed a method to conduct sensitivity analysis in sequential decision models, which could increase the credibility of these models among stakeholders.

  6. Global sensitivity analysis by polynomial dimensional decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Sharif, E-mail: rahman@engineering.uiowa.ed [College of Engineering, The University of Iowa, Iowa City, IA 52242 (United States)

    2011-07-15

    This paper presents a polynomial dimensional decomposition (PDD) method for global sensitivity analysis of stochastic systems subject to independent random input following arbitrary probability distributions. The method involves Fourier-polynomial expansions of lower-variate component functions of a stochastic response by measure-consistent orthonormal polynomial bases, analytical formulae for calculating the global sensitivity indices in terms of the expansion coefficients, and dimension-reduction integration for estimating the expansion coefficients. Due to identical dimensional structures of PDD and analysis-of-variance decomposition, the proposed method facilitates simple and direct calculation of the global sensitivity indices. Numerical results of the global sensitivity indices computed for smooth systems reveal significantly higher convergence rates of the PDD approximation than those from existing methods, including polynomial chaos expansion, random balance design, state-dependent parameter, improved Sobol's method, and sampling-based methods. However, for non-smooth functions, the convergence properties of the PDD solution deteriorate to a great extent, warranting further improvements. The computational complexity of the PDD method is polynomial, as opposed to exponential, thereby alleviating the curse of dimensionality to some extent.

  7. Demonstration sensitivity analysis for RADTRAN III

    International Nuclear Information System (INIS)

    Neuhauser, K.S.; Reardon, P.C.

    1986-10-01

    A demonstration sensitivity analysis was performed to: quantify the relative importance of 37 variables to the total incident free dose; assess the elasticity of seven dose subgroups to those same variables; develop density distributions for accident dose to combinations of accident data under wide-ranging variations; show the relationship between accident consequences and probabilities of occurrence; and develop limits for the variability of probability consequence curves

  8. Sensitivity of LUCC on the Surface Temperature of Tibetan Plateau

    Science.gov (United States)

    Qi, W.; Deng, X.; Wu, F.

    2016-12-01

    The Tibetan Plateau has an important effect on the ecological security in China, even in Asia, which makes the region become the hot spot in recently research. Under the joint influence of global change and human activities, ecosystem destabilizing and the increasing pressure on resources and environment emerge on the Tibetan Plateau, but the potential spatial sensitivity of land use and land cover changes(LUCC) on surface temperature has not been quantitatively analyzed. This study analyzed the mainly types of LUCC, urbanization, grassland degradation, deforestation on Tibetan Plateau along with Representative Concentration Pathways (RCPs) of the Intergovernmental Panel on Climate Change (IPCC). The LUCC in recent decades was first quantitatively analyzed in this study to give the basic fact with a significant increase in temperatures, reduced precipitation and increased evaporation. This study focused on the future spatio-temporal heterogeneity of the temperature and precipitation. Finally, the influencing factors with LUCC on Tibetan Plateau were simulated with the Weather Research and Forecasting (WRF) model, and the sensitivity of different land use types was spatially analyzed with Singular Value Decomposition (SVD). The results indicate that the large-area alpine grassland plays a more important role in alleviating global warming than other vegetation types do. The changes of the landscape structure resulting from the urban expansion play a significant role in intensifying regional temperature increase. In addition, the effects of LUCC on monthly average temperature change would vary from month to month with obviously spatial heterogeneity.

  9. Systemization of burnup sensitivity analysis code. 2

    International Nuclear Information System (INIS)

    Tatsumi, Masahiro; Hyoudou, Hideaki

    2005-02-01

    Towards the practical use of fast reactors, it is a very important subject to improve prediction accuracy for neutronic properties in LMFBR cores from the viewpoint of improvements on plant efficiency with rationally high performance cores and that on reliability and safety margins. A distinct improvement on accuracy in nuclear core design has been accomplished by the development of adjusted nuclear library using the cross-section adjustment method, in which the results of criticality experiments of JUPITER and so on are reflected. In the design of large LMFBR cores, however, it is important to accurately estimate not only neutronic characteristics, for example, reaction rate distribution and control rod worth but also burnup characteristics, for example, burnup reactivity loss, breeding ratio and so on. For this purpose, it is desired to improve prediction accuracy of burnup characteristics using the data widely obtained in actual core such as the experimental fast reactor 'JOYO'. The analysis of burnup characteristics is needed to effectively use burnup characteristics data in the actual cores based on the cross-section adjustment method. So far, a burnup sensitivity analysis code, SAGEP-BURN, has been developed and confirmed its effectiveness. However, there is a problem that analysis sequence become inefficient because of a big burden to users due to complexity of the theory of burnup sensitivity and limitation of the system. It is also desired to rearrange the system for future revision since it is becoming difficult to implement new functions in the existing large system. It is not sufficient to unify each computational component for the following reasons; the computational sequence may be changed for each item being analyzed or for purpose such as interpretation of physical meaning. Therefore, it is needed to systemize the current code for burnup sensitivity analysis with component blocks of functionality that can be divided or constructed on occasion. For

  10. Interdependencies of Arctic land surface processes: A uniquely sensitive environment

    Science.gov (United States)

    Bowling, L. C.

    2007-12-01

    The circumpolar arctic drainage basin is composed of several distinct ecoregions including steppe grassland and cropland, boreal forest and tundra. Land surface hydrology throughout this diverse region shares several unique features such as dramatic seasonal runoff differences controlled by snowmelt and ice break-up; the storage of significant portions of annual precipitation as snow and in lakes and wetlands; and the effects of ephemeral and permanently frozen soils. These arctic land processes are delicately balanced with the climate and are therefore important indicators of change. The litany of recently-detected changes in the Arctic includes changes in snow precipitation, trends and seasonal shifts in river discharge, increases and decreases in the extent of surface water, and warming soil temperatures. Although not unique to the arctic, increasing anthropogenic pressures represent an additional element of change in the form of resource extraction, fire threat and reservoir construction. The interdependence of the physical, biological and social systems mean that changes in primary indicators have large implications for land cover, animal populations and the regional carbon balance, all of which have the potential to feed back and induce further change. In fact, the complex relationships between the hydrological processes that make the Artic unique also render observed historical change difficult to interpret and predict, leading to conflicting explanations. For example, a decrease in snow accumulation may provide less insulation to the underlying soil resulting in greater frost development and increased spring runoff. Similarly, melting permafrost and ground ice may lead to ground subsidence and increased surface saturation and methane production, while more complete thaw may enhance drainage and result in drier soil conditions. The threshold nature of phase change around the freezing point makes the system especially sensitive to change. In addition, spatial

  11. Systemization of burnup sensitivity analysis code

    International Nuclear Information System (INIS)

    Tatsumi, Masahiro; Hyoudou, Hideaki

    2004-02-01

    To practical use of fact reactors, it is a very important subject to improve prediction accuracy for neutronic properties in LMFBR cores from the viewpoints of improvements on plant efficiency with rationally high performance cores and that on reliability and safety margins. A distinct improvement on accuracy in nuclear core design has been accomplished by development of adjusted nuclear library using the cross-section adjustment method, in which the results of critical experiments of JUPITER and so on are reflected. In the design of large LMFBR cores, however, it is important to accurately estimate not only neutronic characteristics, for example, reaction rate distribution and control rod worth but also burnup characteristics, for example, burnup reactivity loss, breeding ratio and so on. For this purpose, it is desired to improve prediction accuracy of burnup characteristics using the data widely obtained in actual core such as the experimental fast reactor core 'JOYO'. The analysis of burnup characteristics is needed to effectively use burnup characteristics data in the actual cores based on the cross-section adjustment method. So far, development of a analysis code for burnup sensitivity, SAGEP-BURN, has been done and confirmed its effectiveness. However, there is a problem that analysis sequence become inefficient because of a big burden to user due to complexity of the theory of burnup sensitivity and limitation of the system. It is also desired to rearrange the system for future revision since it is becoming difficult to implement new functionalities in the existing large system. It is not sufficient to unify each computational component for some reasons; computational sequence may be changed for each item being analyzed or for purpose such as interpretation of physical meaning. Therefore it is needed to systemize the current code for burnup sensitivity analysis with component blocks of functionality that can be divided or constructed on occasion. For this

  12. Sensitivity analysis of critical experiment with direct perturbation compared to TSUNAMI-3D sensitivity analysis

    International Nuclear Information System (INIS)

    Barber, A. D.; Busch, R.

    2009-01-01

    The goal of this work is to obtain sensitivities from direct uncertainty analysis calculation and correlate those calculated values with the sensitivities produced from TSUNAMI-3D (Tools for Sensitivity and Uncertainty Analysis Methodology Implementation in Three Dimensions). A full sensitivity analysis is performed on a critical experiment to determine the overall uncertainty of the experiment. Small perturbation calculations are performed for all known uncertainties to obtain the total uncertainty of the experiment. The results from a critical experiment are only known as well as the geometric and material properties. The goal of this relationship is to simplify the uncertainty quantification process in assessing a critical experiment, while still considering all of the important parameters. (authors)

  13. Sensitivity analysis of the Two Geometry Method

    International Nuclear Information System (INIS)

    Wichers, V.A.

    1993-09-01

    The Two Geometry Method (TGM) was designed specifically for the verification of the uranium enrichment of low enriched UF 6 gas in the presence of uranium deposits on the pipe walls. Complications can arise if the TGM is applied under extreme conditions, such as deposits larger than several times the gas activity, small pipe diameters less than 40 mm and low pressures less than 150 Pa. This report presents a comprehensive sensitivity analysis of the TGM. The impact of the various sources of uncertainty on the performance of the method is discussed. The application to a practical case is based on worst case conditions with regards to the measurement conditions, and on realistic conditions with respect to the false alarm probability and the non detection probability. Monte Carlo calculations were used to evaluate the sensitivity for sources of uncertainty which are experimentally inaccessible. (orig.)

  14. SURFAN, a programme for surface analysis

    International Nuclear Information System (INIS)

    Negoita, F.; Borcan, C.; Pantelica, D.

    1997-01-01

    Possible alternatives to Rutherford backscattering spectrometry (RBS) method of material analysis, overcoming the poor sensitivity to light elements of RBS, are the nuclear resonant reaction analysis (NRA) and elastic recoil detection analysis (ERDA). The last one is especially useful in surface and thin film analysis. To simulate the spectra obtained with any of these methods a programme SURFAN was worked out. In comparison with the code RUMP, published by Doolittle, it allows to simply change the charge of the projectile nature, implies no limitation to the energy of incident projectiles and permits the use of any depth profile function. The basic ideas and the structure of SURFAN are presented. Its application to ERDA and RBS methods resulted in important information on the processes implied in special materials obtained by advanced technologies

  15. Sensitivity Analysis of Launch Vehicle Debris Risk Model

    Science.gov (United States)

    Gee, Ken; Lawrence, Scott L.

    2010-01-01

    As part of an analysis of the loss of crew risk associated with an ascent abort system for a manned launch vehicle, a model was developed to predict the impact risk of the debris resulting from an explosion of the launch vehicle on the crew module. The model consisted of a debris catalog describing the number, size and imparted velocity of each piece of debris, a method to compute the trajectories of the debris and a method to calculate the impact risk given the abort trajectory of the crew module. The model provided a point estimate of the strike probability as a function of the debris catalog, the time of abort and the delay time between the abort and destruction of the launch vehicle. A study was conducted to determine the sensitivity of the strike probability to the various model input parameters and to develop a response surface model for use in the sensitivity analysis of the overall ascent abort risk model. The results of the sensitivity analysis and the response surface model are presented in this paper.

  16. Sensitivity analysis of reactive ecological dynamics.

    Science.gov (United States)

    Verdy, Ariane; Caswell, Hal

    2008-08-01

    Ecological systems with asymptotically stable equilibria may exhibit significant transient dynamics following perturbations. In some cases, these transient dynamics include the possibility of excursions away from the equilibrium before the eventual return; systems that exhibit such amplification of perturbations are called reactive. Reactivity is a common property of ecological systems, and the amplification can be large and long-lasting. The transient response of a reactive ecosystem depends on the parameters of the underlying model. To investigate this dependence, we develop sensitivity analyses for indices of transient dynamics (reactivity, the amplification envelope, and the optimal perturbation) in both continuous- and discrete-time models written in matrix form. The sensitivity calculations require expressions, some of them new, for the derivatives of equilibria, eigenvalues, singular values, and singular vectors, obtained using matrix calculus. Sensitivity analysis provides a quantitative framework for investigating the mechanisms leading to transient growth. We apply the methodology to a predator-prey model and a size-structured food web model. The results suggest predator-driven and prey-driven mechanisms for transient amplification resulting from multispecies interactions.

  17. Global sensitivity analysis using polynomial chaos expansions

    International Nuclear Information System (INIS)

    Sudret, Bruno

    2008-01-01

    Global sensitivity analysis (SA) aims at quantifying the respective effects of input random variables (or combinations thereof) onto the variance of the response of a physical or mathematical model. Among the abundant literature on sensitivity measures, the Sobol' indices have received much attention since they provide accurate information for most models. The paper introduces generalized polynomial chaos expansions (PCE) to build surrogate models that allow one to compute the Sobol' indices analytically as a post-processing of the PCE coefficients. Thus the computational cost of the sensitivity indices practically reduces to that of estimating the PCE coefficients. An original non intrusive regression-based approach is proposed, together with an experimental design of minimal size. Various application examples illustrate the approach, both from the field of global SA (i.e. well-known benchmark problems) and from the field of stochastic mechanics. The proposed method gives accurate results for various examples that involve up to eight input random variables, at a computational cost which is 2-3 orders of magnitude smaller than the traditional Monte Carlo-based evaluation of the Sobol' indices

  18. Global sensitivity analysis using polynomial chaos expansions

    Energy Technology Data Exchange (ETDEWEB)

    Sudret, Bruno [Electricite de France, R and D Division, Site des Renardieres, F 77818 Moret-sur-Loing Cedex (France)], E-mail: bruno.sudret@edf.fr

    2008-07-15

    Global sensitivity analysis (SA) aims at quantifying the respective effects of input random variables (or combinations thereof) onto the variance of the response of a physical or mathematical model. Among the abundant literature on sensitivity measures, the Sobol' indices have received much attention since they provide accurate information for most models. The paper introduces generalized polynomial chaos expansions (PCE) to build surrogate models that allow one to compute the Sobol' indices analytically as a post-processing of the PCE coefficients. Thus the computational cost of the sensitivity indices practically reduces to that of estimating the PCE coefficients. An original non intrusive regression-based approach is proposed, together with an experimental design of minimal size. Various application examples illustrate the approach, both from the field of global SA (i.e. well-known benchmark problems) and from the field of stochastic mechanics. The proposed method gives accurate results for various examples that involve up to eight input random variables, at a computational cost which is 2-3 orders of magnitude smaller than the traditional Monte Carlo-based evaluation of the Sobol' indices.

  19. Contributions to sensitivity analysis and generalized discriminant analysis

    International Nuclear Information System (INIS)

    Jacques, J.

    2005-12-01

    Two topics are studied in this thesis: sensitivity analysis and generalized discriminant analysis. Global sensitivity analysis of a mathematical model studies how the output variables of this last react to variations of its inputs. The methods based on the study of the variance quantify the part of variance of the response of the model due to each input variable and each subset of input variables. The first subject of this thesis is the impact of a model uncertainty on results of a sensitivity analysis. Two particular forms of uncertainty are studied: that due to a change of the model of reference, and that due to the use of a simplified model with the place of the model of reference. A second problem was studied during this thesis, that of models with correlated inputs. Indeed, classical sensitivity indices not having significance (from an interpretation point of view) in the presence of correlation of the inputs, we propose a multidimensional approach consisting in expressing the sensitivity of the output of the model to groups of correlated variables. Applications in the field of nuclear engineering illustrate this work. Generalized discriminant analysis consists in classifying the individuals of a test sample in groups, by using information contained in a training sample, when these two samples do not come from the same population. This work extends existing methods in a Gaussian context to the case of binary data. An application in public health illustrates the utility of generalized discrimination models thus defined. (author)

  20. Enhancement in sensitivity of graphene-based zinc oxide assisted bimetallic surface plasmon resonance (SPR) biosensor

    Science.gov (United States)

    Kumar, Rajeev; Kushwaha, Angad S.; Srivastava, Monika; Mishra, H.; Srivastava, S. K.

    2018-03-01

    In the present communication, a highly sensitive surface plasmon resonance (SPR) biosensor with Kretschmann configuration having alternate layers, prism/zinc oxide/silver/gold/graphene/biomolecules (ss-DNA) is presented. The optimization of the proposed configuration has been accomplished by keeping the constant thickness of zinc oxide (32 nm), silver (32 nm), graphene (0.34 nm) layer and biomolecules (100 nm) for different values of gold layer thickness (1, 3 and 5 nm). The sensitivity of the proposed SPR biosensor has been demonstrated for a number of design parameters such as gold layer thickness, number of graphene layer, refractive index of biomolecules and the thickness of biomolecules layer. SPR biosensor with optimized geometry has greater sensitivity (66 deg/RIU) than the conventional (52 deg/RIU) as well as other graphene-based (53.2 deg/RIU) SPR biosensor. The effect of zinc oxide layer thickness on the sensitivity of SPR biosensor has also been analysed. From the analysis, it is found that the sensitivity increases significantly by increasing the thickness of zinc oxide layer. It means zinc oxide intermediate layer plays an important role to improve the sensitivity of the biosensor. The sensitivity of SPR biosensor also increases by increasing the number of graphene layer (upto nine layer).

  1. Simple Sensitivity Analysis for Orion GNC

    Science.gov (United States)

    Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar

    2013-01-01

    The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch.We describe in this paper a sensitivity analysis tool (Critical Factors Tool or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.

  2. Sensitivity analysis of floating offshore wind farms

    International Nuclear Information System (INIS)

    Castro-Santos, Laura; Diaz-Casas, Vicente

    2015-01-01

    Highlights: • Develop a sensitivity analysis of a floating offshore wind farm. • Influence on the life-cycle costs involved in a floating offshore wind farm. • Influence on IRR, NPV, pay-back period, LCOE and cost of power. • Important variables: distance, wind resource, electric tariff, etc. • It helps to investors to take decisions in the future. - Abstract: The future of offshore wind energy will be in deep waters. In this context, the main objective of the present paper is to develop a sensitivity analysis of a floating offshore wind farm. It will show how much the output variables can vary when the input variables are changing. For this purpose two different scenarios will be taken into account: the life-cycle costs involved in a floating offshore wind farm (cost of conception and definition, cost of design and development, cost of manufacturing, cost of installation, cost of exploitation and cost of dismantling) and the most important economic indexes in terms of economic feasibility of a floating offshore wind farm (internal rate of return, net present value, discounted pay-back period, levelized cost of energy and cost of power). Results indicate that the most important variables in economic terms are the number of wind turbines and the distance from farm to shore in the costs’ scenario, and the wind scale parameter and the electric tariff for the economic indexes. This study will help investors to take into account these variables in the development of floating offshore wind farms in the future

  3. Sensitivity of Rayleigh wave ellipticity and implications for surface wave inversion

    Science.gov (United States)

    Cercato, Michele

    2018-04-01

    The use of Rayleigh wave ellipticity has gained increasing popularity in recent years for investigating earth structures, especially for near-surface soil characterization. In spite of its widespread application, the sensitivity of the ellipticity function to the soil structure has been rarely explored in a comprehensive and systematic manner. To this end, a new analytical method is presented for computing the sensitivity of Rayleigh wave ellipticity with respect to the structural parameters of a layered elastic half-space. This method takes advantage of the minor decomposition of the surface wave eigenproblem and is numerically stable at high frequency. This numerical procedure allowed to retrieve the sensitivity for typical near surface and crustal geological scenarios, pointing out the key parameters for ellipticity interpretation under different circumstances. On this basis, a thorough analysis is performed to assess how ellipticity data can efficiently complement surface wave dispersion information in a joint inversion algorithm. The results of synthetic and real-world examples are illustrated to analyse quantitatively the diagnostic potential of the ellipticity data with respect to the soil structure, focusing on the possible sources of misinterpretation in data inversion.

  4. Response surfaces and sensitivity analyses for an environmental model of dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Iooss, Bertrand [CEA Cadarache, DEN/DER/SESI/LCFR, 13108 Saint Paul lez Durance, Cedex (France)]. E-mail: bertrand.iooss@cea.fr; Van Dorpe, Francois [CEA Cadarache, DEN/DTN/SMTM/LMTE, 13108 Saint Paul lez Durance, Cedex (France); Devictor, Nicolas [CEA Cadarache, DEN/DER/SESI/LCFR, 13108 Saint Paul lez Durance, Cedex (France)

    2006-10-15

    A parametric sensitivity analysis is carried out on GASCON, a radiological impact software describing the radionuclides transfer to the man following a chronic gas release of a nuclear facility. An effective dose received by age group can thus be calculated according to a specific radionuclide and to the duration of the release. In this study, we are concerned by 18 output variables, each depending of approximately 50 uncertain input parameters. First, the generation of 1000 Monte-Carlo simulations allows us to calculate correlation coefficients between input parameters and output variables, which give a first overview of important factors. Response surfaces are then constructed in polynomial form, and used to predict system responses at reduced computation time cost; this response surface will be very useful for global sensitivity analysis where thousands of runs are required. Using the response surfaces, we calculate the total sensitivity indices of Sobol by the Monte-Carlo method. We demonstrate the application of this method to one site of study and to one reference group near the nuclear research Center of Cadarache (France), for two radionuclides: iodine 129 and uranium 238. It is thus shown that the most influential parameters are all related to the food chain of the goat's milk, in decreasing order of importance: dose coefficient 'effective ingestion', goat's milk ration of the individuals of the reference group, grass ration of the goat, dry deposition velocity and transfer factor to the goat's milk.

  5. Ocular surface sensitivity repeatability with Cochet-Bonnet esthesiometer.

    Science.gov (United States)

    Chao, Cecilia; Stapleton, Fiona; Badarudin, Ezailina; Golebiowski, Blanka

    2015-02-01

    To determine the repeatability of ocular surface threshold measurements using the Cochet-Bonnet esthesiometer on the same day and 3 months apart. Two separate studies were conducted to determine the repeatability of ocular surface threshold measurements made on the same day (n = 20 subjects) and 3 months apart (n = 29 subjects). The Cochet-Bonnet esthesiometer was used to measure corneal and inferior conjunctival thresholds using the ascending method of limits. The pressure exerted by the Cochet-Bonnet esthesiometer was determined using an analytical balance, for both the 0.08- and 0.12-mm-diameter filaments. This calibration was then used to convert filament length measurements to pressure. Repeatability was determined using a Bland and Altman analysis. The pressure exerted at each filament length differed between the two filament diameters. The measured pressure also differed from values provided by the manufacturer. Repeatability of threshold measurements at the central cornea was shown to be good, with better repeatability for same-day measurements (coefficient of repeatability [CoR] = ±0.23 g/mm²) than for those 3 months apart (CoR = ±0.52 g/mm²). Threshold measurements at the inferior conjunctiva, in contrast, were poorly repeatable (CoR = ±12.78 g/mm²). Cochet-Bonnet esthesiometry is repeatable when performed on the central cornea on the same day and 3 months apart, but this instrument is not recommended for conjunctival threshold measurements.

  6. Atomic force microscopy analysis of different surface treatments of Ti dental implant surfaces

    International Nuclear Information System (INIS)

    Bathomarco, R.V.; Solorzano, G.; Elias, C.N.; Prioli, R.

    2004-01-01

    The surface of commercial unalloyed titanium, used in dental implants, was analyzed by atomic force microscopy. The morphology, roughness, and surface area of the samples, submitted to mechanically-induced erosion, chemical etching and a combination of both, were compared. The results show that surface treatments strongly influence the dental implant physical and chemical properties. An analysis of the length dependence of the implant surface roughness shows that, for scan sizes larger than 50 μm, the average surface roughness is independent of the scanning length and that the surface treatments lead to average surface roughness in the range of 0.37 up to 0.48 μm. It is shown that the implant surface energy is sensitive to the titanium surface area. As the area increases there is a decrease in the surface contact angle

  7. Atomic force microscopy analysis of different surface treatments of Ti dental implant surfaces

    Science.gov (United States)

    Bathomarco, Ti R. V.; Solorzano, G.; Elias, C. N.; Prioli, R.

    2004-06-01

    The surface of commercial unalloyed titanium, used in dental implants, was analyzed by atomic force microscopy. The morphology, roughness, and surface area of the samples, submitted to mechanically-induced erosion, chemical etching and a combination of both, were compared. The results show that surface treatments strongly influence the dental implant physical and chemical properties. An analysis of the length dependence of the implant surface roughness shows that, for scan sizes larger than 50 μm, the average surface roughness is independent of the scanning length and that the surface treatments lead to average surface roughness in the range of 0.37 up to 0.48 μm. It is shown that the implant surface energy is sensitive to the titanium surface area. As the area increases there is a decrease in the surface contact angle.

  8. Sensitivity analysis of a modified energy model

    International Nuclear Information System (INIS)

    Suganthi, L.; Jagadeesan, T.R.

    1997-01-01

    Sensitivity analysis is carried out to validate model formulation. A modified model has been developed to predict the future energy requirement of coal, oil and electricity, considering price, income, technological and environmental factors. The impact and sensitivity of the independent variables on the dependent variable are analysed. The error distribution pattern in the modified model as compared to a conventional time series model indicated the absence of clusters. The residual plot of the modified model showed no distinct pattern of variation. The percentage variation of error in the conventional time series model for coal and oil ranges from -20% to +20%, while for electricity it ranges from -80% to +20%. However, in the case of the modified model the percentage variation in error is greatly reduced - for coal it ranges from -0.25% to +0.15%, for oil -0.6% to +0.6% and for electricity it ranges from -10% to +10%. The upper and lower limit consumption levels at 95% confidence is determined. The consumption at varying percentage changes in price and population are analysed. The gap between the modified model predictions at varying percentage changes in price and population over the years from 1990 to 2001 is found to be increasing. This is because of the increasing rate of energy consumption over the years and also the confidence level decreases as the projection is made far into the future. (author)

  9. Sensitivity Analysis for Design Optimization Integrated Software Tools, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this proposed project is to provide a new set of sensitivity analysis theory and codes, the Sensitivity Analysis for Design Optimization Integrated...

  10. Sensitivity analysis approaches applied to systems biology models.

    Science.gov (United States)

    Zi, Z

    2011-11-01

    With the rising application of systems biology, sensitivity analysis methods have been widely applied to study the biological systems, including metabolic networks, signalling pathways and genetic circuits. Sensitivity analysis can provide valuable insights about how robust the biological responses are with respect to the changes of biological parameters and which model inputs are the key factors that affect the model outputs. In addition, sensitivity analysis is valuable for guiding experimental analysis, model reduction and parameter estimation. Local and global sensitivity analysis approaches are the two types of sensitivity analysis that are commonly applied in systems biology. Local sensitivity analysis is a classic method that studies the impact of small perturbations on the model outputs. On the other hand, global sensitivity analysis approaches have been applied to understand how the model outputs are affected by large variations of the model input parameters. In this review, the author introduces the basic concepts of sensitivity analysis approaches applied to systems biology models. Moreover, the author discusses the advantages and disadvantages of different sensitivity analysis methods, how to choose a proper sensitivity analysis approach, the available sensitivity analysis tools for systems biology models and the caveats in the interpretation of sensitivity analysis results.

  11. A new importance measure for sensitivity analysis

    International Nuclear Information System (INIS)

    Liu, Qiao; Homma, Toshimitsu

    2010-01-01

    Uncertainty is an integral part of risk assessment of complex engineering systems, such as nuclear power plants and space crafts. The aim of sensitivity analysis is to identify the contribution of the uncertainty in model inputs to the uncertainty in the model output. In this study, a new importance measure that characterizes the influence of the entire input distribution on the entire output distribution was proposed. It represents the expected deviation of the cumulative distribution function (CDF) of the model output that would be obtained when one input parameter of interest were known. The applicability of this importance measure was tested with two models, a nonlinear nonmonotonic mathematical model and a risk model. In addition, a comparison of this new importance measure with several other importance measures was carried out and the differences between these measures were explained. (author)

  12. DEA Sensitivity Analysis for Parallel Production Systems

    Directory of Open Access Journals (Sweden)

    J. Gerami

    2011-06-01

    Full Text Available In this paper, we introduce systems consisting of several production units, each of which include several subunits working in parallel. Meanwhile, each subunit is working independently. The input and output of each production unit are the sums of the inputs and outputs of its subunits, respectively. We consider each of these subunits as an independent decision making unit(DMU and create the production possibility set(PPS produced by these DMUs, in which the frontier points are considered as efficient DMUs. Then we introduce models for obtaining the efficiency of the production subunits. Using super-efficiency models, we categorize all efficient subunits into different efficiency classes. Then we follow by presenting the sensitivity analysis and stability problem for efficient subunits, including extreme efficient and non-extreme efficient subunits, assuming simultaneous perturbations in all inputs and outputs of subunits such that the efficiency of the subunit under evaluation declines while the efficiencies of other subunits improve.

  13. Sensitivity of SBLOCA analysis to model nodalization

    International Nuclear Information System (INIS)

    Lee, C.; Ito, T.; Abramson, P.B.

    1983-01-01

    The recent Semiscale test S-UT-8 indicates the possibility for primary liquid to hang up in the steam generators during a SBLOCA, permitting core uncovery prior to loop-seal clearance. In analysis of Small Break Loss of Coolant Accidents with RELAP5, it is found that resultant transient behavior is quite sensitive to the selection of nodalization for the steam generators. Although global parameters such as integrated mass loss, primary inventory and primary pressure are relatively insensitive to the nodalization, it is found that the predicted distribution of inventory around the primary is significantly affected by nodalization. More detailed nodalization predicts that more of the inventory tends to remain in the steam generators, resulting in less inventory in the reactor vessel and therefore causing earlier and more severe core uncovery

  14. Subset simulation for structural reliability sensitivity analysis

    International Nuclear Information System (INIS)

    Song Shufang; Lu Zhenzhou; Qiao Hongwei

    2009-01-01

    Based on two procedures for efficiently generating conditional samples, i.e. Markov chain Monte Carlo (MCMC) simulation and importance sampling (IS), two reliability sensitivity (RS) algorithms are presented. On the basis of reliability analysis of Subset simulation (Subsim), the RS of the failure probability with respect to the distribution parameter of the basic variable is transformed as a set of RS of conditional failure probabilities with respect to the distribution parameter of the basic variable. By use of the conditional samples generated by MCMC simulation and IS, procedures are established to estimate the RS of the conditional failure probabilities. The formulae of the RS estimator, its variance and its coefficient of variation are derived in detail. The results of the illustrations show high efficiency and high precision of the presented algorithms, and it is suitable for highly nonlinear limit state equation and structural system with single and multiple failure modes

  15. Linear regression and sensitivity analysis in nuclear reactor design

    International Nuclear Information System (INIS)

    Kumar, Akansha; Tsvetkov, Pavel V.; McClarren, Ryan G.

    2015-01-01

    Highlights: • Presented a benchmark for the applicability of linear regression to complex systems. • Applied linear regression to a nuclear reactor power system. • Performed neutronics, thermal–hydraulics, and energy conversion using Brayton’s cycle for the design of a GCFBR. • Performed detailed sensitivity analysis to a set of parameters in a nuclear reactor power system. • Modeled and developed reactor design using MCNP, regression using R, and thermal–hydraulics in Java. - Abstract: The paper presents a general strategy applicable for sensitivity analysis (SA), and uncertainity quantification analysis (UA) of parameters related to a nuclear reactor design. This work also validates the use of linear regression (LR) for predictive analysis in a nuclear reactor design. The analysis helps to determine the parameters on which a LR model can be fit for predictive analysis. For those parameters, a regression surface is created based on trial data and predictions are made using this surface. A general strategy of SA to determine and identify the influential parameters those affect the operation of the reactor is mentioned. Identification of design parameters and validation of linearity assumption for the application of LR of reactor design based on a set of tests is performed. The testing methods used to determine the behavior of the parameters can be used as a general strategy for UA, and SA of nuclear reactor models, and thermal hydraulics calculations. A design of a gas cooled fast breeder reactor (GCFBR), with thermal–hydraulics, and energy transfer has been used for the demonstration of this method. MCNP6 is used to simulate the GCFBR design, and perform the necessary criticality calculations. Java is used to build and run input samples, and to extract data from the output files of MCNP6, and R is used to perform regression analysis and other multivariate variance, and analysis of the collinearity of data

  16. Structure sensitivity of CO dissociation on Rh surfaces

    DEFF Research Database (Denmark)

    Mavrikakis, Manos; Baumer, M.; Freund, H.J.

    2002-01-01

    than the flat surface, but the effect is considerably weaker than the effect of surface structure on the dissociation barrier. Our findings are compared with available experimental data, and the consequences for CO activation in methanation and Fischer-Tropsch reactions are discussed.......Using periodic self-consistent density functional calculations it is shown that the barrier for CO dissociation is similar to120 kJ/mol lower on the stepped Rh(211) surface than on the close-packed Rh(111) surface. The stepped surface binds molecular CO and the dissociation products more strongly...

  17. Calibration, validation, and sensitivity analysis: What's what

    International Nuclear Information System (INIS)

    Trucano, T.G.; Swiler, L.P.; Igusa, T.; Oberkampf, W.L.; Pilch, M.

    2006-01-01

    One very simple interpretation of calibration is to adjust a set of parameters associated with a computational science and engineering code so that the model agreement is maximized with respect to a set of experimental data. One very simple interpretation of validation is to quantify our belief in the predictive capability of a computational code through comparison with a set of experimental data. Uncertainty in both the data and the code are important and must be mathematically understood to correctly perform both calibration and validation. Sensitivity analysis, being an important methodology in uncertainty analysis, is thus important to both calibration and validation. In this paper, we intend to clarify the language just used and express some opinions on the associated issues. We will endeavor to identify some technical challenges that must be resolved for successful validation of a predictive modeling capability. One of these challenges is a formal description of a 'model discrepancy' term. Another challenge revolves around the general adaptation of abstract learning theory as a formalism that potentially encompasses both calibration and validation in the face of model uncertainty

  18. Track sensitivity and the surface roughness measurements of CR-39 with atomic force microscope

    CERN Document Server

    Yasuda, N; Amemiya, K; Takahashi, H; Kyan, A; Ogura, K

    1999-01-01

    Atomic Force Microscope (AFM) has been applied to evaluate the surface roughness and the track sensitivity of CR-39 track detector. We experimentally confirmed the inverse correlation between the track sensitivity and the roughness of the detector surface after etching. The surface of CR-39 (CR-39 doped with antioxidant (HARZLAS (TD-1)) and copolymer of CR-39/NIPAAm (TNF-1)) with high sensitivity becomes rough by the etching, while the pure CR-39 (BARYOTRAK) with low sensitivity keeps its original surface clarity even for the long etching.

  19. Global sensitivity analysis in wind energy assessment

    Science.gov (United States)

    Tsvetkova, O.; Ouarda, T. B.

    2012-12-01

    Wind energy is one of the most promising renewable energy sources. Nevertheless, it is not yet a common source of energy, although there is enough wind potential to supply world's energy demand. One of the most prominent obstacles on the way of employing wind energy is the uncertainty associated with wind energy assessment. Global sensitivity analysis (SA) studies how the variation of input parameters in an abstract model effects the variation of the variable of interest or the output variable. It also provides ways to calculate explicit measures of importance of input variables (first order and total effect sensitivity indices) in regard to influence on the variation of the output variable. Two methods of determining the above mentioned indices were applied and compared: the brute force method and the best practice estimation procedure In this study a methodology for conducting global SA of wind energy assessment at a planning stage is proposed. Three sampling strategies which are a part of SA procedure were compared: sampling based on Sobol' sequences (SBSS), Latin hypercube sampling (LHS) and pseudo-random sampling (PRS). A case study of Masdar City, a showcase of sustainable living in the UAE, is used to exemplify application of the proposed methodology. Sources of uncertainty in wind energy assessment are very diverse. In the case study the following were identified as uncertain input parameters: the Weibull shape parameter, the Weibull scale parameter, availability of a wind turbine, lifetime of a turbine, air density, electrical losses, blade losses, ineffective time losses. Ineffective time losses are defined as losses during the time when the actual wind speed is lower than the cut-in speed or higher than the cut-out speed. The output variable in the case study is the lifetime energy production. Most influential factors for lifetime energy production are identified with the ranking of the total effect sensitivity indices. The results of the present

  20. Surface analysis and techniques in biology

    CERN Document Server

    Smentkowski, Vincent S

    2014-01-01

    This book highlights state-of-the-art surface analytical instrumentation, advanced data analysis tools, and the use of complimentary surface analytical instrumentation to perform a complete analysis of biological systems.

  1. Frontier Assignment for Sensitivity Analysis of Data Envelopment Analysis

    Science.gov (United States)

    Naito, Akio; Aoki, Shingo; Tsuji, Hiroshi

    To extend the sensitivity analysis capability for DEA (Data Envelopment Analysis), this paper proposes frontier assignment based DEA (FA-DEA). The basic idea of FA-DEA is to allow a decision maker to decide frontier intentionally while the traditional DEA and Super-DEA decide frontier computationally. The features of FA-DEA are as follows: (1) provides chances to exclude extra-influential DMU (Decision Making Unit) and finds extra-ordinal DMU, and (2) includes the function of the traditional DEA and Super-DEA so that it is able to deal with sensitivity analysis more flexibly. Simple numerical study has shown the effectiveness of the proposed FA-DEA and the difference from the traditional DEA.

  2. Sensitivity analysis of Smith's AMRV model

    International Nuclear Information System (INIS)

    Ho, Chih-Hsiang

    1995-01-01

    Multiple-expert hazard/risk assessments have considerable precedent, particularly in the Yucca Mountain site characterization studies. In this paper, we present a Bayesian approach to statistical modeling in volcanic hazard assessment for the Yucca Mountain site. Specifically, we show that the expert opinion on the site disruption parameter p is elicited on the prior distribution, π (p), based on geological information that is available. Moreover, π (p) can combine all available geological information motivated by conflicting but realistic arguments (e.g., simulation, cluster analysis, structural control, etc.). The incorporated uncertainties about the probability of repository disruption p, win eventually be averaged out by taking the expectation over π (p). We use the following priors in the analysis: priors chosen for mathematical convenience: Beta (r, s) for (r, s) = (2, 2), (3, 3), (5, 5), (2, 1), (2, 8), (8, 2), and (1, 1); and three priors motivated by expert knowledge. Sensitivity analysis is performed for each prior distribution. Estimated values of hazard based on the priors chosen for mathematical simplicity are uniformly higher than those obtained based on the priors motivated by expert knowledge. And, the model using the prior, Beta (8,2), yields the highest hazard (= 2.97 X 10 -2 ). The minimum hazard is produced by the open-quotes three-expert priorclose quotes (i.e., values of p are equally likely at 10 -3 10 -2 , and 10 -1 ). The estimate of the hazard is 1.39 x which is only about one order of magnitude smaller than the maximum value. The term, open-quotes hazardclose quotes, is defined as the probability of at least one disruption of a repository at the Yucca Mountain site by basaltic volcanism for the next 10,000 years

  3. Wear-Out Sensitivity Analysis Project Abstract

    Science.gov (United States)

    Harris, Adam

    2015-01-01

    During the course of the Summer 2015 internship session, I worked in the Reliability and Maintainability group of the ISS Safety and Mission Assurance department. My project was a statistical analysis of how sensitive ORU's (Orbital Replacement Units) are to a reliability parameter called the wear-out characteristic. The intended goal of this was to determine a worst case scenario of how many spares would be needed if multiple systems started exhibiting wear-out characteristics simultaneously. The goal was also to determine which parts would be most likely to do so. In order to do this, my duties were to take historical data of operational times and failure times of these ORU's and use them to build predictive models of failure using probability distribution functions, mainly the Weibull distribution. Then, I ran Monte Carlo Simulations to see how an entire population of these components would perform. From here, my final duty was to vary the wear-out characteristic from the intrinsic value, to extremely high wear-out values and determine how much the probability of sufficiency of the population would shift. This was done for around 30 different ORU populations on board the ISS.

  4. Supercritical extraction of oleaginous: parametric sensitivity analysis

    Directory of Open Access Journals (Sweden)

    Santos M.M.

    2000-01-01

    Full Text Available The economy has become universal and competitive, thus the industries of vegetable oil extraction must advance in the sense of minimising production costs and, at the same time, generating products that obey more rigorous patterns of quality, including solutions that do not damage the environment. The conventional oilseed processing uses hexane as solvent. However, this solvent is toxic and highly flammable. Thus the search of substitutes for hexane in oleaginous extraction process has increased in the last years. The supercritical carbon dioxide is a potential substitute for hexane, but it is necessary more detailed studies to understand the phenomena taking place in such process. Thus, in this work a diffusive model for semi-continuous (batch for the solids and continuous for the solvent isothermal and isobaric extraction process using supercritical carbon dioxide is presented and submitted to a parametric sensitivity analysis by means of a factorial design in two levels. The model parameters were disturbed and their main effects analysed, so that it is possible to propose strategies for high performance operation.

  5. Ion induced optical emission for surface and depth profile analysis

    International Nuclear Information System (INIS)

    White, C.W.

    1977-01-01

    Low-energy ion bombardment of solid surfaces results in the emission of infrared, visible, and ultraviolet radiation produced by inelastic ion-solid collision processes. The emitted optical radiation provides important insight into low-energy particle-solid interactions and provides the basis for an analysis technique which can be used for surface and depth profile analysis with high sensitivity. The different kinds of collision induced optical radiation emitted as a result of low-energy particle-solid collisions are reviewed. Line radiation arising from excited states of sputtered atoms or molecules is shown to provide the basis for surface and depth profile analysis. The spectral characteristics of this type of radiation are discussed and applications of the ion induced optical emission technique are presented. These applications include measurements of ion implant profiles, detection sensitivities for submonolayer quantities of impurities on elemental surfaces, and the detection of elemental impurities on complex organic substrates

  6. Sensitivity analysis of ranked data: from order statistics to quantiles

    NARCIS (Netherlands)

    Heidergott, B.F.; Volk-Makarewicz, W.

    2015-01-01

    In this paper we provide the mathematical theory for sensitivity analysis of order statistics of continuous random variables, where the sensitivity is with respect to a distributional parameter. Sensitivity analysis of order statistics over a finite number of observations is discussed before

  7. SENSIT: a cross-section and design sensitivity and uncertainty analysis code

    International Nuclear Information System (INIS)

    Gerstl, S.A.W.

    1980-01-01

    SENSIT computes the sensitivity and uncertainty of a calculated integral response (such as a dose rate) due to input cross sections and their uncertainties. Sensitivity profiles are computed for neutron and gamma-ray reaction cross sections of standard multigroup cross section sets and for secondary energy distributions (SEDs) of multigroup scattering matrices. In the design sensitivity mode, SENSIT computes changes in an integral response due to design changes and gives the appropriate sensitivity coefficients. Cross section uncertainty analyses are performed for three types of input data uncertainties: cross-section covariance matrices for pairs of multigroup reaction cross sections, spectral shape uncertainty parameters for secondary energy distributions (integral SED uncertainties), and covariance matrices for energy-dependent response functions. For all three types of data uncertainties SENSIT computes the resulting variance and estimated standard deviation in an integral response of interest, on the basis of generalized perturbation theory. SENSIT attempts to be more comprehensive than earlier sensitivity analysis codes, such as SWANLAKE

  8. A surface plasmon resonance-based immunosensors for sensitive detection of heroin

    International Nuclear Information System (INIS)

    Wu Zhongcheng; Wang Lianchao; Ge Yu; Yu Chengduan; Fang Tingjian; Chen Wenge

    2000-01-01

    A simple technique for sensitive detection of heroine based on surface-plasmon resonance has been theoretically and experimentally investigated. The experiment was realized by using an anti-MO monoclonal antibody and a morphine (MO)-bovine serum albumin (MO-BSA) conjugate (antigen). The reason for using MO-BSA in the detection of heroine was also discussed. MO-BSA was immobilized on a gold thin film of SPR sensor chip by physical adsorption. The configuration of the device is allowed to be further miniaturized, which is required for the construction of a portable SPR device in the application of in-situ analysis

  9. Multitarget global sensitivity analysis of n-butanol combustion.

    Science.gov (United States)

    Zhou, Dingyu D Y; Davis, Michael J; Skodje, Rex T

    2013-05-02

    A model for the combustion of butanol is studied using a recently developed theoretical method for the systematic improvement of the kinetic mechanism. The butanol mechanism includes 1446 reactions, and we demonstrate that it is straightforward and computationally feasible to implement a full global sensitivity analysis incorporating all the reactions. In addition, we extend our previous analysis of ignition-delay targets to include species targets. The combination of species and ignition targets leads to multitarget global sensitivity analysis, which allows for a more complete mechanism validation procedure than we previously implemented. The inclusion of species sensitivity analysis allows for a direct comparison between reaction pathway analysis and global sensitivity analysis.

  10. Sensitivity analysis in multi-parameter probabilistic systems

    International Nuclear Information System (INIS)

    Walker, J.R.

    1987-01-01

    Probabilistic methods involving the use of multi-parameter Monte Carlo analysis can be applied to a wide range of engineering systems. The output from the Monte Carlo analysis is a probabilistic estimate of the system consequence, which can vary spatially and temporally. Sensitivity analysis aims to examine how the output consequence is influenced by the input parameter values. Sensitivity analysis provides the necessary information so that the engineering properties of the system can be optimized. This report details a package of sensitivity analysis techniques that together form an integrated methodology for the sensitivity analysis of probabilistic systems. The techniques have known confidence limits and can be applied to a wide range of engineering problems. The sensitivity analysis methodology is illustrated by performing the sensitivity analysis of the MCROC rock microcracking model

  11. An ESDIRK Method with Sensitivity Analysis Capabilities

    DEFF Research Database (Denmark)

    Kristensen, Morten Rode; Jørgensen, John Bagterp; Thomsen, Per Grove

    2004-01-01

    of the sensitivity equations. A key feature is the reuse of information already computed for the state integration, hereby minimizing the extra effort required for sensitivity integration. Through case studies the new algorithm is compared to an extrapolation method and to the more established BDF based approaches...

  12. Sensitivity Analysis of Fire Dynamics Simulation

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter V.; Petersen, Arnkell J.

    2007-01-01

    (Morris method). The parameters considered are selected among physical parameters and program specific parameters. The influence on the calculation result as well as the CPU time is considered. It is found that the result is highly sensitive to many parameters even though the sensitivity varies...

  13. Surface sensitization mechanism on negative electron affinity p-GaN nanowires

    Science.gov (United States)

    Diao, Yu; Liu, Lei; Xia, Sihao; Feng, Shu; Lu, Feifei

    2018-03-01

    The surface sensitization is the key to prepare negative electron affinity photocathode. The thesis emphasizes on the study of surface sensitization mechanism of p-type doping GaN nanowires utilizing first principles based on density function theory. The adsorption energy, work function, dipole moment, geometry structure, electronic structure and optical properties of Mg-doped GaN nanowires surfaces with various coverages of Cs atoms are investigated. The GaN nanowire with Mg doped in core position is taken as the sensitization base. At the initial stage of sensitization, the best adsorption site for Cs atom on GaN nanowire surface is BN, the bridge site of two adjacent N atoms. Surface sensitization generates a p-type internal surface with an n-type surface state, introducing a band bending region which can help reduce surface barrier and work function. With increasing Cs coverage, work functions decrease monotonously and the "Cs-kill" phenomenon disappears. For Cs coverage of 0.75 ML and 1 ML, the corresponding sensitization systems reach negative electron affinity state. Through surface sensitization, the absorption curves are red shifted and the absorption coefficient is cut down. All theoretical calculations can guide the design of negative electron affinity Mg doped GaN nanowires photocathode.

  14. Superconducting Accelerating Cavity Pressure Sensitivity Analysis

    International Nuclear Information System (INIS)

    Rodnizki, J.; Horvits, Z.; Ben Aliz, Y.; Grin, A.; Weissman, L.

    2014-01-01

    The measured sensitivity of the cavity was evaluated and it is full consistent with the measured values. It was explored that the tuning system (the fog structure) has a significant contribution to the cavity sensitivity. By using ribs or by modifying the rigidity of the fog we may reduce the HWR sensitivity. During cool down and warming up we have to analyze the stresses on the HWR to avoid plastic deformation to the HWR since the Niobium yield is an order of magnitude lower in room temperature

  15. Derivative based sensitivity analysis of gamma index

    Directory of Open Access Journals (Sweden)

    Biplab Sarkar

    2015-01-01

    Full Text Available Originally developed as a tool for patient-specific quality assurance in advanced treatment delivery methods to compare between measured and calculated dose distributions, the gamma index (γ concept was later extended to compare between any two dose distributions. It takes into effect both the dose difference (DD and distance-to-agreement (DTA measurements in the comparison. Its strength lies in its capability to give a quantitative value for the analysis, unlike other methods. For every point on the reference curve, if there is at least one point in the evaluated curve that satisfies the pass criteria (e.g., δDD = 1%, δDTA = 1 mm, the point is included in the quantitative score as "pass." Gamma analysis does not account for the gradient of the evaluated curve - it looks at only the minimum gamma value, and if it is <1, then the point passes, no matter what the gradient of evaluated curve is. In this work, an attempt has been made to present a derivative-based method for the identification of dose gradient. A mathematically derived reference profile (RP representing the penumbral region of 6 MV 10 cm × 10 cm field was generated from an error function. A general test profile (GTP was created from this RP by introducing 1 mm distance error and 1% dose error at each point. This was considered as the first of the two evaluated curves. By its nature, this curve is a smooth curve and would satisfy the pass criteria for all points in it. The second evaluated profile was generated as a sawtooth test profile (STTP which again would satisfy the pass criteria for every point on the RP. However, being a sawtooth curve, it is not a smooth one and would be obviously poor when compared with the smooth profile. Considering the smooth GTP as an acceptable profile when it passed the gamma pass criteria (1% DD and 1 mm DTA against the RP, the first and second order derivatives of the DDs (δD', δD" between these two curves were derived and used as the

  16. MOVES2010a regional level sensitivity analysis

    Science.gov (United States)

    2012-12-10

    This document discusses the sensitivity of various input parameter effects on emission rates using the US Environmental Protection Agencys (EPAs) MOVES2010a model at the regional level. Pollutants included in the study are carbon monoxide (CO),...

  17. Surface plasmon resonance biosensors for highly sensitive detection in real samples

    Science.gov (United States)

    Sepúlveda, B.; Carrascosa, L. G.; Regatos, D.; Otte, M. A.; Fariña, D.; Lechuga, L. M.

    2009-08-01

    In this work we summarize the main results obtained with the portable surface plasmon resonance (SPR) device developed in our group (commercialised by SENSIA, SL, Spain), highlighting its applicability for the real-time detection of extremely low concentrations of toxic pesticides in environmental water samples. In addition, we show applications in clinical diagnosis as, on the one hand, the real-time and label-free detection of DNA hybridization and single point mutations at the gene BRCA-1, related to the predisposition in women to develop an inherited breast cancer and, on the other hand, the analysis of protein biomarkers in biological samples (urine, serum) for early detection of diseases. Despite the large number of applications already proven, the SPR technology has two main drawbacks: (i) not enough sensitivity for some specific applications (where pM-fM or single-molecule detection are needed) (ii) low multiplexing capabilities. In order solve such drawbacks, we work in several alternative configurations as the Magneto-optical Surface Plasmon Resonance sensor (MOSPR) based on a combination of magnetooptical and ferromagnetic materials, to improve the SPR sensitivity, or the Localized Surface Plasmon Resonance (LSPR) based on nanostructures (nanoparticles, nanoholes,...), for higher multiplexing capabilities.

  18. New sensitive micro-measurements of dynamic surface tension and diffusion coefficients

    DEFF Research Database (Denmark)

    Kinoshita, Koji; Ortiz, Elisa Parra; Needham, David

    2017-01-01

    Currently available dynamic surface tension (DST) measurement methods, such as Wilhelmy plate, droplet- or bubble-based methods, still have various experimental limitations such as the large size of the interface, convection in the solution, or a certain “dead time” at initial measurement....... These limitations create inconsistencies for the kinetic analysis of surfactant adsorption/desorption, especially significant for ionic surfactants. Here, the “micropipette interfacial area-expansion method” was introduced and validated as a new DST measurement having a high enough sensitivity to detect diffusion...... for surface excess concentration. We found that the measured diffusion coefficient of 1-Octanol, 7.2 ± 0.8 × 10−6 cm2/s, showed excellent agreement with the result from an alternative method, “single microdroplet catching method”, to measure the diffusion coefficient from diffusion-controlled microdroplet...

  19. Sensitivity analysis techniques applied to a system of hyperbolic conservation laws

    International Nuclear Information System (INIS)

    Weirs, V. Gregory; Kamm, James R.; Swiler, Laura P.; Tarantola, Stefano; Ratto, Marco; Adams, Brian M.; Rider, William J.; Eldred, Michael S.

    2012-01-01

    Sensitivity analysis is comprised of techniques to quantify the effects of the input variables on a set of outputs. In particular, sensitivity indices can be used to infer which input parameters most significantly affect the results of a computational model. With continually increasing computing power, sensitivity analysis has become an important technique by which to understand the behavior of large-scale computer simulations. Many sensitivity analysis methods rely on sampling from distributions of the inputs. Such sampling-based methods can be computationally expensive, requiring many evaluations of the simulation; in this case, the Sobol' method provides an easy and accurate way to compute variance-based measures, provided a sufficient number of model evaluations are available. As an alternative, meta-modeling approaches have been devised to approximate the response surface and estimate various measures of sensitivity. In this work, we consider a variety of sensitivity analysis methods, including different sampling strategies, different meta-models, and different ways of evaluating variance-based sensitivity indices. The problem we consider is the 1-D Riemann problem. By a careful choice of inputs, discontinuous solutions are obtained, leading to discontinuous response surfaces; such surfaces can be particularly problematic for meta-modeling approaches. The goal of this study is to compare the estimated sensitivity indices with exact values and to evaluate the convergence of these estimates with increasing samples sizes and under an increasing number of meta-model evaluations. - Highlights: ► Sensitivity analysis techniques for a model shock physics problem are compared. ► The model problem and the sensitivity analysis problem have exact solutions. ► Subtle details of the method for computing sensitivity indices can affect the results.

  20. Procedures for uncertainty and sensitivity analysis in repository performance assessment

    International Nuclear Information System (INIS)

    Poern, K.; Aakerlund, O.

    1985-10-01

    The objective of the project was mainly a literature study of available methods for the treatment of parameter uncertainty propagation and sensitivity aspects in complete models such as those concerning geologic disposal of radioactive waste. The study, which has run parallel with the development of a code package (PROPER) for computer assisted analysis of function, also aims at the choice of accurate, cost-affective methods for uncertainty and sensitivity analysis. Such a choice depends on several factors like the number of input parameters, the capacity of the model and the computer reresources required to use the model. Two basic approaches are addressed in the report. In one of these the model of interest is directly simulated by an efficient sampling technique to generate an output distribution. Applying the other basic method the model is replaced by an approximating analytical response surface, which is then used in the sampling phase or in moment matching to generate the output distribution. Both approaches are illustrated by simple examples in the report. (author)

  1. NPV Sensitivity Analysis: A Dynamic Excel Approach

    Science.gov (United States)

    Mangiero, George A.; Kraten, Michael

    2017-01-01

    Financial analysts generally create static formulas for the computation of NPV. When they do so, however, it is not readily apparent how sensitive the value of NPV is to changes in multiple interdependent and interrelated variables. It is the aim of this paper to analyze this variability by employing a dynamic, visually graphic presentation using…

  2. Sensitivity Analysis for Multidisciplinary Systems (SAMS)

    Science.gov (United States)

    2016-12-01

    release. Distribution is unlimited. 14 Server and Client Code Server from geometry import Point, Geometry import math import zmq class Server...public release; Distribution is unlimited. DISTRIBUTION STATEMENT A: Approved for public release. Distribution is unlimited. 19 Example Application Boeing...Materials Conference, 2011. Cross, D. M., Local continuum sensitivity method for shape design derivatives using spatial gradient reconstruction. Diss

  3. Global Analysis of Minimal Surfaces

    CERN Document Server

    Dierkes, Ulrich; Tromba, Anthony J

    2010-01-01

    Many properties of minimal surfaces are of a global nature, and this is already true for the results treated in the first two volumes of the treatise. Part I of the present book can be viewed as an extension of these results. For instance, the first two chapters deal with existence, regularity and uniqueness theorems for minimal surfaces with partially free boundaries. Here one of the main features is the possibility of 'edge-crawling' along free parts of the boundary. The third chapter deals with a priori estimates for minimal surfaces in higher dimensions and for minimizers of singular integ

  4. A new method for background rejection with surface sensitive bolometers

    International Nuclear Information System (INIS)

    Nones, C.; Foggetta, L.; Giuliani, A.; Pedretti, M.; Salvioni, C.; Sangiorgio, S.

    2006-01-01

    We report the performance of three prototype TeO 2 macrobolometers, able to identify events due to energy deposited at the detector surface. This capability is obtained by thermally coupling thin active layers to the main absorber of the bolometer, and is proved by irradiating the detectors with alpha particles. This technique can be very useful in view of background study and reduction for the CUORE experiment, a next generation Double Beta Decay search based on TeO 2 macrobolometers and to be installed in the Laboratori Nazionali del Gran Sasso

  5. Gap Surface Plasmon Waveguide Analysis

    DEFF Research Database (Denmark)

    Nielsen, Michael Grøndahl; Bozhevolnyi, Sergey I.

    2014-01-01

    Plasmonic waveguides supporting gap surface plasmons (GSPs) localized in a dielectric spacer between metal films are investigated numerically and the waveguiding properties at telecommunication wavelengths are presented. Especially, we emphasize that the mode confinement can advantageously...

  6. Extended forward sensitivity analysis of one-dimensional isothermal flow

    International Nuclear Information System (INIS)

    Johnson, M.; Zhao, H.

    2013-01-01

    Sensitivity analysis and uncertainty quantification is an important part of nuclear safety analysis. In this work, forward sensitivity analysis is used to compute solution sensitivities on 1-D fluid flow equations typical of those found in system level codes. Time step sensitivity analysis is included as a method for determining the accumulated error from time discretization. The ability to quantify numerical error arising from the time discretization is a unique and important feature of this method. By knowing the relative sensitivity of time step with other physical parameters, the simulation is allowed to run at optimized time steps without affecting the confidence of the physical parameter sensitivity results. The time step forward sensitivity analysis method can also replace the traditional time step convergence studies that are a key part of code verification with much less computational cost. One well-defined benchmark problem with manufactured solutions is utilized to verify the method; another test isothermal flow problem is used to demonstrate the extended forward sensitivity analysis process. Through these sample problems, the paper shows the feasibility and potential of using the forward sensitivity analysis method to quantify uncertainty in input parameters and time step size for a 1-D system-level thermal-hydraulic safety code. (authors)

  7. The role of sensitivity analysis in probabilistic safety assessment

    International Nuclear Information System (INIS)

    Hirschberg, S.; Knochenhauer, M.

    1987-01-01

    The paper describes several items suitable for close examination by means of application of sensitivity analysis, when performing a level 1 PSA. Sensitivity analyses are performed with respect to; (1) boundary conditions, (2) operator actions, and (3) treatment of common cause failures (CCFs). The items of main interest are identified continuously in the course of performing a PSA, as well as by scrutinising the final results. The practical aspects of sensitivity analysis are illustrated by several applications from a recent PSA study (ASEA-ATOM BWR 75). It is concluded that sensitivity analysis leads to insights important for analysts, reviewers and decision makers. (orig./HP)

  8. Automated sensitivity analysis using the GRESS language

    International Nuclear Information System (INIS)

    Pin, F.G.; Oblow, E.M.; Wright, R.Q.

    1986-04-01

    An automated procedure for performing large-scale sensitivity studies based on the use of computer calculus is presented. The procedure is embodied in a FORTRAN precompiler called GRESS, which automatically processes computer models and adds derivative-taking capabilities to the normal calculated results. In this report, the GRESS code is described, tested against analytic and numerical test problems, and then applied to a major geohydrological modeling problem. The SWENT nuclear waste repository modeling code is used as the basis for these studies. Results for all problems are discussed in detail. Conclusions are drawn as to the applicability of GRESS in the problems at hand and for more general large-scale modeling sensitivity studies

  9. Sensitivity Analysis of a Simplified Fire Dynamic Model

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt; Nielsen, Anker

    2015-01-01

    This paper discusses a method for performing a sensitivity analysis of parameters used in a simplified fire model for temperature estimates in the upper smoke layer during a fire. The results from the sensitivity analysis can be used when individual parameters affecting fire safety are assessed...

  10. Sensitive molecular diagnostics using surface-enhanced resonance Raman scattering (SERRS)

    Science.gov (United States)

    Faulds, Karen; Graham, Duncan; McKenzie, Fiona; MacRae, Douglas; Ricketts, Alastair; Dougan, Jennifer

    2009-02-01

    Surface enhanced resonance Raman scattering (SERRS) is an analytical technique with several advantages over competitive techniques in terms of improved sensitivity and multiplexing. We have made great progress in the development of SERRS as a quantitative analytical method, in particular for the detection of DNA. SERRS is an extremely sensitive and selective technique which when applied to the detection of labelled DNA sequences allows detection limits to be obtained which rival, and in most cases, are better than fluorescence. Here the conditions are explored which will enable the successful detection of DNA using SERRS. The enhancing surface which is used is crucial and in this case suspensions of nanoparticles were used as they allow quantitative behaviour to be achieved and allow analogous systems to current fluorescence based systems to be made. The aggregation conditions required to obtain SERRS of DNA are crucial and herein we describe the use of spermine as an aggregating agent. The nature of the label which is used, be it fluorescent, positively or negatively charged also effects the SERRS response and these conditions are again explored here. We have clearly demonstrated the ability to identify the components of a mixture of 5 analytes in solution by using two different excitation wavelengths and also of a 6-plex using data analysis techniques. These conditions will allow the use of SERRS for the detection of target DNA in a meaningful diagnostic assay.

  11. Sensitive determination of dopamine levels via surface-enhanced Raman scattering of Ag nanoparticle dimers.

    Science.gov (United States)

    Yu, Xiantong; He, XiaoXiao; Yang, Taiqun; Zhao, Litao; Chen, Qichen; Zhang, Sanjun; Chen, Jinquan; Xu, Jianhua

    2018-01-01

    Dopamine (DA) is an important neurotransmitter in the hypothalamus and pituitary gland, which can produce a direct influence on mammals' emotions in midbrain. Additionally, the level of DA is highly related with some important neurologic diseases such as schizophrenia, Parkinson, and Huntington's diseases, etc. In light of the important roles that DA plays in the disease modulation, it is of considerable significance to develop a sensitive and reproducible approach for monitoring DA. The objective of this study was to develop an efficient approach to quantitatively monitor the level of DA using Ag nanoparticle (NP) dimers and enhanced Raman spectroscopy. Ag NP dimers were synthesized for the sensitive detection of DA via surface-enhanced Raman scattering (SERS). Citrate was used as both the capping agent of NPs and sensing agent to DA, which is self-assembled on the surface of Ag NP dimers by reacting with the surface carboxyl group to form a stable amide bond. To improve accuracy and precision, the multiplicative effects model for surface-enhanced Raman spectroscopy was utilized to analyze the SERS assays. A low limits of detection (LOD) of 20 pM and a wide linear response range from 30 pM to 300 nM were obtained for DA quantitative detection. The SERS enhancement factor was theoretically valued at approximately 10 7 by discrete dipole approximation. DA was self-assembled on the citrate capped surface of Ag NPs dimers through the amide bond. The adsorption energy was estimated to be 256 KJ/mol using the Langmuir isotherm model. The density functional theory was used to simulate the spectral characteristics of SERS during the adsorption of DA on the surface of the Ag dimers. Furthermore, to improve the accuracy and precision of quantitative analysis of SERS assays with a multiplicative effects model for surface-enhanced Raman spectroscopy. A LOD of 20 pM DA-level was obtained, and the linear response ranged from 30 pM to 300 nM for quantitative DA detection. The

  12. Highly sensitive nano-porous lattice biosensor based on localized surface plasmon resonance and interference.

    Science.gov (United States)

    Yeom, Se-Hyuk; Kim, Ok-Geun; Kang, Byoung-Ho; Kim, Kyu-Jin; Yuan, Heng; Kwon, Dae-Hyuk; Kim, Hak-Rin; Kang, Shin-Won

    2011-11-07

    We propose a design for a highly sensitive biosensor based on nanostructured anodized aluminum oxide (AAO) substrates. A gold-deposited AAO substrate exhibits both optical interference and localized surface plasmon resonance (LSPR). In our sensor, application of these disparate optical properties overcomes problems of limited sensitivity, selectivity, and dynamic range seen in similar biosensors. We fabricated uniform periodic nanopore lattice AAO templates by two-step anodizing and assessed their suitability for application in biosensors by characterizing the change in optical response on addition of biomolecules to the AAO template. To determine the suitability of such structures for biosensing applications, we immobilized a layer of C-reactive protein (CRP) antibody on a gold coating atop an AAO template. We then applied a CRP antigen (Ag) atop the immobilized antibody (Ab) layer. The shift in reflectance is interpreted as being caused by the change in refractive index with membrane thickness. Our results confirm that our proposed AAO-based biosensor is highly selective toward detection of CRP antigen, and can measure a change in CRP antigen concentration of 1 fg/ml. This method can provide a simple, fast, and sensitive analysis for protein detection in real-time.

  13. Space-Based Diagnosis of Surface Ozone Sensitivity to Anthropogenic Emissions

    Science.gov (United States)

    Martin, Randall V.; Fiore, Arlene M.; VanDonkelaar, Aaron

    2004-01-01

    We present a novel capability in satellite remote sensing with implications for air pollution control strategy. We show that the ratio of formaldehyde columns to tropospheric nitrogen dioxide columns is an indicator of the relative sensitivity of surface ozone to emissions of nitrogen oxides (NO(x) = NO + NO2) and volatile organic compounds (VOCs). The diagnosis from these space-based observations is highly consistent with current understanding of surface ozone chemistry based on in situ observations. The satellite-derived ratios indicate that surface ozone is more sensitive to emissions of NO(x) than of VOCs throughout most continental regions of the Northern Hemisphere during summer. Exceptions include Los Angeles and industrial areas of Germany. A seasonal transition occurs in the fall when surface ozone becomes less sensitive to NOx and more sensitive to VOCs.

  14. Sensitivity analysis of a low-level waste environmental transport code

    International Nuclear Information System (INIS)

    Hiromoto, G.

    1989-01-01

    Results are presented from a sensivity analysis of a computer code designed to simulate the environmental transport of radionuclides buried at shallow land waste repositories. A sensitivity analysis methodology, based on the surface response replacement and statistic sensitivity estimators, was developed to address the relative importance of the input parameters on the model output. Response surface replacement for the model was constructed by stepwise regression, after sampling input vectors from range and distribution of the input variables, and running the code to generate the associated output data. Sensitivity estimators were compute using the partial rank correlation coefficients and the standardized rank regression coefficients. The results showed that the tecniques employed in this work provides a feasible means to perform a sensitivity analysis of a general not-linear environmental radionuclides transport models. (author) [pt

  15. Parameter identification and global sensitivity analysis of Xin'anjiang model using meta-modeling approach

    Directory of Open Access Journals (Sweden)

    Xiao-meng Song

    2013-01-01

    Full Text Available Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on (1 a screening method (Morris for qualitative ranking of parameters, and (2 a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model (RSMSobol. First, the Morris screening method was used to qualitatively identify the parameters' sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model (RSM were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.

  16. In-vacuum scattered light reduction with black cupric oxide surfaces for sensitive fluorescence detection.

    Science.gov (United States)

    Norrgard, E B; Sitaraman, N; Barry, J F; McCarron, D J; Steinecker, M H; DeMille, D

    2016-05-01

    We demonstrate a simple and easy method for producing low-reflectivity surfaces that are ultra-high vacuum compatible, may be baked to high temperatures, and are easily applied even on complex surface geometries. Black cupric oxide (CuO) surfaces are chemically grown in minutes on any copper surface, allowing for low-cost, rapid prototyping, and production. The reflective properties are measured to be comparable to commercially available products for creating optically black surfaces. We describe a vacuum apparatus which uses multiple blackened copper surfaces for sensitive, low-background detection of molecules using laser-induced fluorescence.

  17. Calculating the sensitivity of wind turbine loads to wind inputs using response surfaces

    DEFF Research Database (Denmark)

    Rinker, Jennifer M.

    2016-01-01

    at a low computational cost. Sobol sensitivity indices (SIs) can then be calculated with relative ease using the calibrated response surface. The proposed methodology is demonstrated by calculating the total sensitivity of the maximum blade root bending moment of the WindPACT 5 MW reference model to four......This paper presents a methodology to calculate wind turbine load sensitivities to turbulence parameters through the use of response surfaces. A response surface is a high-dimensional polynomial surface that can be calibrated to any set of input/output data and then used to generate synthetic data...... turbulence input parameters: a reference mean wind speed, a reference turbulence intensity, the Kaimal length scale, and a novel parameter reflecting the nonstationarity present in the inflow turbulence. The input/output data used to calibrate the response surface were generated for a previous project...

  18. Global Sensitivity Analysis of Environmental Models: Convergence, Robustness and Validation

    Science.gov (United States)

    Sarrazin, Fanny; Pianosi, Francesca; Khorashadi Zadeh, Farkhondeh; Van Griensven, Ann; Wagener, Thorsten

    2015-04-01

    Global Sensitivity Analysis aims to characterize the impact that variations in model input factors (e.g. the parameters) have on the model output (e.g. simulated streamflow). In sampling-based Global Sensitivity Analysis, the sample size has to be chosen carefully in order to obtain reliable sensitivity estimates while spending computational resources efficiently. Furthermore, insensitive parameters are typically identified through the definition of a screening threshold: the theoretical value of their sensitivity index is zero but in a sampling-base framework they regularly take non-zero values. There is little guidance available for these two steps in environmental modelling though. The objective of the present study is to support modellers in making appropriate choices, regarding both sample size and screening threshold, so that a robust sensitivity analysis can be implemented. We performed sensitivity analysis for the parameters of three hydrological models with increasing level of complexity (Hymod, HBV and SWAT), and tested three widely used sensitivity analysis methods (Elementary Effect Test or method of Morris, Regional Sensitivity Analysis, and Variance-Based Sensitivity Analysis). We defined criteria based on a bootstrap approach to assess three different types of convergence: the convergence of the value of the sensitivity indices, of the ranking (the ordering among the parameters) and of the screening (the identification of the insensitive parameters). We investigated the screening threshold through the definition of a validation procedure. The results showed that full convergence of the value of the sensitivity indices is not necessarily needed to rank or to screen the model input factors. Furthermore, typical values of the sample sizes that are reported in the literature can be well below the sample sizes that actually ensure convergence of ranking and screening.

  19. Automating sensitivity analysis of computer models using computer calculus

    International Nuclear Information System (INIS)

    Oblow, E.M.; Pin, F.G.

    1986-01-01

    An automated procedure for performing sensitivity analysis has been developed. The procedure uses a new FORTRAN compiler with computer calculus capabilities to generate the derivatives needed to set up sensitivity equations. The new compiler is called GRESS - Gradient Enhanced Software System. Application of the automated procedure with direct and adjoint sensitivity theory for the analysis of non-linear, iterative systems of equations is discussed. Calculational efficiency consideration and techniques for adjoint sensitivity analysis are emphasized. The new approach is found to preserve the traditional advantages of adjoint theory while removing the tedious human effort previously needed to apply this theoretical methodology. Conclusions are drawn about the applicability of the automated procedure in numerical analysis and large-scale modelling sensitivity studies

  20. Accelerated Sensitivity Analysis in High-Dimensional Stochastic Reaction Networks.

    Science.gov (United States)

    Arampatzis, Georgios; Katsoulakis, Markos A; Pantazis, Yannis

    2015-01-01

    Existing sensitivity analysis approaches are not able to handle efficiently stochastic reaction networks with a large number of parameters and species, which are typical in the modeling and simulation of complex biochemical phenomena. In this paper, a two-step strategy for parametric sensitivity analysis for such systems is proposed, exploiting advantages and synergies between two recently proposed sensitivity analysis methodologies for stochastic dynamics. The first method performs sensitivity analysis of the stochastic dynamics by means of the Fisher Information Matrix on the underlying distribution of the trajectories; the second method is a reduced-variance, finite-difference, gradient-type sensitivity approach relying on stochastic coupling techniques for variance reduction. Here we demonstrate that these two methods can be combined and deployed together by means of a new sensitivity bound which incorporates the variance of the quantity of interest as well as the Fisher Information Matrix estimated from the first method. The first step of the proposed strategy labels sensitivities using the bound and screens out the insensitive parameters in a controlled manner. In the second step of the proposed strategy, a finite-difference method is applied only for the sensitivity estimation of the (potentially) sensitive parameters that have not been screened out in the first step. Results on an epidermal growth factor network with fifty parameters and on a protein homeostasis with eighty parameters demonstrate that the proposed strategy is able to quickly discover and discard the insensitive parameters and in the remaining potentially sensitive parameters it accurately estimates the sensitivities. The new sensitivity strategy can be several times faster than current state-of-the-art approaches that test all parameters, especially in "sloppy" systems. In particular, the computational acceleration is quantified by the ratio between the total number of parameters over the

  1. Accelerated Sensitivity Analysis in High-Dimensional Stochastic Reaction Networks.

    Directory of Open Access Journals (Sweden)

    Georgios Arampatzis

    Full Text Available Existing sensitivity analysis approaches are not able to handle efficiently stochastic reaction networks with a large number of parameters and species, which are typical in the modeling and simulation of complex biochemical phenomena. In this paper, a two-step strategy for parametric sensitivity analysis for such systems is proposed, exploiting advantages and synergies between two recently proposed sensitivity analysis methodologies for stochastic dynamics. The first method performs sensitivity analysis of the stochastic dynamics by means of the Fisher Information Matrix on the underlying distribution of the trajectories; the second method is a reduced-variance, finite-difference, gradient-type sensitivity approach relying on stochastic coupling techniques for variance reduction. Here we demonstrate that these two methods can be combined and deployed together by means of a new sensitivity bound which incorporates the variance of the quantity of interest as well as the Fisher Information Matrix estimated from the first method. The first step of the proposed strategy labels sensitivities using the bound and screens out the insensitive parameters in a controlled manner. In the second step of the proposed strategy, a finite-difference method is applied only for the sensitivity estimation of the (potentially sensitive parameters that have not been screened out in the first step. Results on an epidermal growth factor network with fifty parameters and on a protein homeostasis with eighty parameters demonstrate that the proposed strategy is able to quickly discover and discard the insensitive parameters and in the remaining potentially sensitive parameters it accurately estimates the sensitivities. The new sensitivity strategy can be several times faster than current state-of-the-art approaches that test all parameters, especially in "sloppy" systems. In particular, the computational acceleration is quantified by the ratio between the total number of

  2. Surface analysis of selected hydrophobic materials

    Science.gov (United States)

    Wisniewska, Sylwia Katarzyna

    This dissertation contains a series of studies on hydrophobic surfaces by various surface sensitive techniques such as contact angle measurements, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Hydrophobic surfaces have been classified as mineral surfaces, organic synthetic surfaces, or natural biological surfaces. As a model hydrophobic mineral surface, elemental sulfur has been selected. The sulfur surface has been characterized for selected allotropic forms of sulfur such as rhombic, monoclinic, plastic, and cyclohexasulfur. Additionally, dextrin adsorption at the sulfur surface was measured. The structure of a dextrin molecule showing hydrophobic sites has been presented to support the proposed hydrophobic bonding nature of dextrin adsorption at the sulfur surface. As a model organic hydrophobic surface, primary fatty amines such as dodecylamine, hexadecylamine, and octadecylamine were chosen. An increase of hydrophobicity, significant changes of infrared bands, and surface topographical changes with time were observed for each amine. Based on the results it was concluded that hydrocarbon chain rearrangement associated with recrystallization took place at the surface during contact with air. A barley straw surface was selected as a model of biological hydrophobic surfaces. The differences in the contact angles for various straw surfaces were explained by the presence of a wax layer. SEM images confirmed the heterogeneity and complexity of the wax crystal structure. AFM measurements provided additional structural details including a measure of surface roughness. Additionally, straw degradation as a result of conditioning in an aqueous environment was studied. Significant contact angle changes were observed as soon as one day after conditioning. FTIR studies showed a gradual wax layer removal due to straw surface decomposition. SEM and AFM images revealed topographical changes and biological

  3. Surface computing and collaborative analysis work

    CERN Document Server

    Brown, Judith; Gossage, Stevenson; Hack, Chris

    2013-01-01

    Large surface computing devices (wall-mounted or tabletop) with touch interfaces and their application to collaborative data analysis, an increasingly important and prevalent activity, is the primary topic of this book. Our goals are to outline the fundamentals of surface computing (a still maturing technology), review relevant work on collaborative data analysis, describe frameworks for understanding collaborative processes, and provide a better understanding of the opportunities for research and development. We describe surfaces as display technologies with which people can interact directly, and emphasize how interaction design changes when designing for large surfaces. We review efforts to use large displays, surfaces or mixed display environments to enable collaborative analytic activity. Collaborative analysis is important in many domains, but to provide concrete examples and a specific focus, we frequently consider analysis work in the security domain, and in particular the challenges security personne...

  4. Applications of surface analysis and surface theory in tribology

    Science.gov (United States)

    Ferrante, John

    1989-01-01

    Tribology, the study of adhesion, friction and wear of materials, is a complex field which requires a knowledge of solid state physics, surface physics, chemistry, material science, and mechanical engineering. It has been dominated, however, by the more practical need to make equipment work. With the advent of surface analysis and advances in surface and solid-state theory, a new dimension has been added to the analysis of interactions at tribological interfaces. In this paper the applications of tribological studies and their limitations are presented. Examples from research at the NASA Lewis Research Center are given. Emphasis is on fundamental studies involving the effects of monolayer coverage and thick films on friction and wear. A summary of the current status of theoretical calculations of defect energetics is presented. In addition, some new theoretical techniques which enable simplified quantitative calculations of adhesion, fracture, and friction are discussed.

  5. Engineering of Surface Chemistry for Enhanced Sensitivity in Nanoporous Interferometric Sensing Platforms.

    Science.gov (United States)

    Law, Cheryl Suwen; Sylvia, Georgina M; Nemati, Madieh; Yu, Jingxian; Losic, Dusan; Abell, Andrew D; Santos, Abel

    2017-03-15

    We explore new approaches to engineering the surface chemistry of interferometric sensing platforms based on nanoporous anodic alumina (NAA) and reflectometric interference spectroscopy (RIfS). Two surface engineering strategies are presented, namely (i) selective chemical functionalization of the inner surface of NAA pores with amine-terminated thiol molecules and (ii) selective chemical functionalization of the top surface of NAA with dithiol molecules. The strong molecular interaction of Au 3+ ions with thiol-containing functional molecules of alkane chain or peptide character provides a model sensing system with which to assess the sensitivity of these NAA platforms by both molecular feature and surface engineering. Changes in the effective optical thickness of the functionalized NAA photonic films (i.e., sensing principle), in response to gold ions, are monitored in real-time by RIfS. 6-Amino-1-hexanethiol (inner surface) and 1,6-hexanedithiol (top surface), the most sensitive functional molecules from approaches i and ii, respectively, were combined into a third sensing strategy whereby the NAA platforms are functionalized on both the top and inner surfaces concurrently. Engineering of the surface according to this approach resulted in an additive enhancement in sensitivity of up to 5-fold compared to previously reported systems. This study advances the rational engineering of surface chemistry for interferometric sensing on nanoporous platforms with potential applications for real-time monitoring of multiple analytes in dynamic environments.

  6. Imaging of surface plasmon polariton interference using phase-sensitive scanning tunneling microscope

    NARCIS (Netherlands)

    Jose, J.; Segerink, Franciscus B.; Korterik, Jeroen P.; Herek, Jennifer Lynn; Offerhaus, Herman L.

    2011-01-01

    We report the surface plasmon polariton interference, generated via a ‘buried’ gold grating, and imaged using a phase-sensitive Photon Scanning Tunneling Microscope (PSTM). The phase-resolved PSTM measurement unravels the complex surface plasmon polariton interference fields at the gold-air

  7. Sensitivity Analysis Based on Markovian Integration by Parts Formula

    Directory of Open Access Journals (Sweden)

    Yongsheng Hang

    2017-10-01

    Full Text Available Sensitivity analysis is widely applied in financial risk management and engineering; it describes the variations brought by the changes of parameters. Since the integration by parts technique for Markov chains is well developed in recent years, in this paper we apply it for computation of sensitivity and show the closed-form expressions for two commonly-used time-continuous Markovian models. By comparison, we conclude that our approach outperforms the existing technique of computing sensitivity on Markovian models.

  8. Advanced Fuel Cycle Economic Sensitivity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    David Shropshire; Kent Williams; J.D. Smith; Brent Boore

    2006-12-01

    A fuel cycle economic analysis was performed on four fuel cycles to provide a baseline for initial cost comparison using the Gen IV Economic Modeling Work Group G4 ECON spreadsheet model, Decision Programming Language software, the 2006 Advanced Fuel Cycle Cost Basis report, industry cost data, international papers, the nuclear power related cost study from MIT, Harvard, and the University of Chicago. The analysis developed and compared the fuel cycle cost component of the total cost of energy for a wide range of fuel cycles including: once through, thermal with fast recycle, continuous fast recycle, and thermal recycle.

  9. The role of sensitivity analysis in assessing uncertainty

    International Nuclear Information System (INIS)

    Crick, M.J.; Hill, M.D.

    1987-01-01

    Outside the specialist world of those carrying out performance assessments considerable confusion has arisen about the meanings of sensitivity analysis and uncertainty analysis. In this paper we attempt to reduce this confusion. We then go on to review approaches to sensitivity analysis within the context of assessing uncertainty, and to outline the types of test available to identify sensitive parameters, together with their advantages and disadvantages. The views expressed in this paper are those of the authors; they have not been formally endorsed by the National Radiological Protection Board and should not be interpreted as Board advice

  10. Analysis of Sensitivity Experiments - An Expanded Primer

    Science.gov (United States)

    2017-03-08

    conducted with this purpose in mind. Due diligence must be paid to the structure of the dosage levels and to the number of trials. The chosen data...analysis. System reliability is of paramount importance for protecting both the investment of funding and human life . Failing to accurately estimate

  11. Sensitivity analysis of hybrid thermoelastic techniques

    Science.gov (United States)

    W.A. Samad; J.M. Considine

    2017-01-01

    Stress functions have been used as a complementary tool to support experimental techniques, such as thermoelastic stress analysis (TSA) and digital image correlation (DIC), in an effort to evaluate the complete and separate full-field stresses of loaded structures. The need for such coupling between experimental data and stress functions is due to the fact that...

  12. Automating sensitivity analysis of computer models using computer calculus

    International Nuclear Information System (INIS)

    Oblow, E.M.; Pin, F.G.

    1985-01-01

    An automated procedure for performing sensitivity analyses has been developed. The procedure uses a new FORTRAN compiler with computer calculus capabilities to generate the derivatives needed to set up sensitivity equations. The new compiler is called GRESS - Gradient Enhanced Software System. Application of the automated procedure with ''direct'' and ''adjoint'' sensitivity theory for the analysis of non-linear, iterative systems of equations is discussed. Calculational efficiency consideration and techniques for adjoint sensitivity analysis are emphasized. The new approach is found to preserve the traditional advantages of adjoint theory while removing the tedious human effort previously needed to apply this theoretical methodology. Conclusions are drawn about the applicability of the automated procedure in numerical analysis and large-scale modelling sensitivity studies. 24 refs., 2 figs

  13. Assessment of wave propagation on surfaces of crystalline lens with phase sensitive optical coherence tomography

    International Nuclear Information System (INIS)

    Manapuram, R K; Larin, K V; Baranov, S A; Manne, V G R; Mashiatulla, M; Sudheendran, N; Aglyamov, S; Emelianov, S

    2011-01-01

    We propose a real-time technique based on phase-sensitive swept source optical coherence tomography (PhS-SSOCT) modality for noninvasive quantification of very small optical path length changes produced on the surface of a mouse crystalline lens. Propagation of submicron mechanical waves on the surface of the lens was induced by periodic mechanical stimulation. Obtained results demonstrate that the described method is capable of detecting minute damped vibrations with amplitudes as small as 30 nanometers on the lens surface and hence, PhS-SSOCT could be potentially used to assess biomechanical properties of a crystalline lens with high accuracy and sensitivity

  14. Sensitivity Analysis of the Critical Speed in Railway Vehicle Dynamics

    DEFF Research Database (Denmark)

    Bigoni, Daniele; True, Hans; Engsig-Karup, Allan Peter

    2014-01-01

    We present an approach to global sensitivity analysis aiming at the reduction of its computational cost without compromising the results. The method is based on sampling methods, cubature rules, High-Dimensional Model Representation and Total Sensitivity Indices. The approach has a general applic...

  15. Global and Local Sensitivity Analysis Methods for a Physical System

    Science.gov (United States)

    Morio, Jerome

    2011-01-01

    Sensitivity analysis is the study of how the different input variations of a mathematical model influence the variability of its output. In this paper, we review the principle of global and local sensitivity analyses of a complex black-box system. A simulated case of application is given at the end of this paper to compare both approaches.…

  16. Adjoint sensitivity analysis of high frequency structures with Matlab

    CERN Document Server

    Bakr, Mohamed; Demir, Veysel

    2017-01-01

    This book covers the theory of adjoint sensitivity analysis and uses the popular FDTD (finite-difference time-domain) method to show how wideband sensitivities can be efficiently estimated for different types of materials and structures. It includes a variety of MATLAB® examples to help readers absorb the content more easily.

  17. Dispersion sensitivity analysis & consistency improvement of APFSDS

    Directory of Open Access Journals (Sweden)

    Sangeeta Sharma Panda

    2017-08-01

    In Bore Balloting Motion simulation shows that reduction in residual spin by about 5% results in drastic 56% reduction in first maximum yaw. A correlation between first maximum yaw and residual spin is observed. Results of data analysis are used in design modification for existing ammunition. Number of designs are evaluated numerically before freezing five designs for further soundings. These designs are critically assessed in terms of their comparative performance during In-bore travel & external ballistics phase. Results are validated by free flight trials for the finalised design.

  18. Adjoint sensitivity analysis of plasmonic structures using the FDTD method.

    Science.gov (United States)

    Zhang, Yu; Ahmed, Osman S; Bakr, Mohamed H

    2014-05-15

    We present an adjoint variable method for estimating the sensitivities of arbitrary responses with respect to the parameters of dispersive discontinuities in nanoplasmonic devices. Our theory is formulated in terms of the electric field components at the vicinity of perturbed discontinuities. The adjoint sensitivities are computed using at most one extra finite-difference time-domain (FDTD) simulation regardless of the number of parameters. Our approach is illustrated through the sensitivity analysis of an add-drop coupler consisting of a square ring resonator between two parallel waveguides. The computed adjoint sensitivities of the scattering parameters are compared with those obtained using the accurate but computationally expensive central finite difference approach.

  19. Sensitivity analysis of the RESRAD, a dose assessment code

    International Nuclear Information System (INIS)

    Yu, C.; Cheng, J.J.; Zielen, A.J.

    1991-01-01

    The RESRAD code is a pathway analysis code that is designed to calculate radiation doses and derive soil cleanup criteria for the US Department of Energy's environmental restoration and waste management program. the RESRAD code uses various pathway and consumption-rate parameters such as soil properties and food ingestion rates in performing such calculations and derivations. As with any predictive model, the accuracy of the predictions depends on the accuracy of the input parameters. This paper summarizes the results of a sensitivity analysis of RESRAD input parameters. Three methods were used to perform the sensitivity analysis: (1) Gradient Enhanced Software System (GRESS) sensitivity analysis software package developed at oak Ridge National Laboratory; (2) direct perturbation of input parameters; and (3) built-in graphic package that shows parameter sensitivities while the RESRAD code is operational

  20. A sensitivity analysis approach to optical parameters of scintillation detectors

    International Nuclear Information System (INIS)

    Ghal-Eh, N.; Koohi-Fayegh, R.

    2008-01-01

    In this study, an extended version of the Monte Carlo light transport code, PHOTRACK, has been used for a sensitivity analysis to estimate the importance of different wavelength-dependent parameters in the modelling of light collection process in scintillators

  1. sensitivity analysis on flexible road pavement life cycle cost model

    African Journals Online (AJOL)

    user

    of sensitivity analysis on a developed flexible pavement life cycle cost model using varying discount rate. The study .... organizations and specific projects needs based. Life-cycle ... developed and completed urban road infrastructure corridor ...

  2. Sobol’ sensitivity analysis for stressor impacts on honeybee colonies

    Science.gov (United States)

    We employ Monte Carlo simulation and nonlinear sensitivity analysis techniques to describe the dynamics of a bee exposure model, VarroaPop. Daily simulations are performed of hive population trajectories, taking into account queen strength, foraging success, mite impacts, weather...

  3. Benchmarking sensitivity of biophysical processes to leaf area changes in land surface models

    Science.gov (United States)

    Forzieri, Giovanni; Duveiller, Gregory; Georgievski, Goran; Li, Wei; Robestson, Eddy; Kautz, Markus; Lawrence, Peter; Ciais, Philippe; Pongratz, Julia; Sitch, Stephen; Wiltshire, Andy; Arneth, Almut; Cescatti, Alessandro

    2017-04-01

    Land surface models (LSM) are widely applied as supporting tools for policy-relevant assessment of climate change and its impact on terrestrial ecosystems, yet knowledge of their performance skills in representing the sensitivity of biophysical processes to changes in vegetation density is still limited. This is particularly relevant in light of the substantial impacts on regional climate associated with the changes in leaf area index (LAI) following the observed global greening. Benchmarking LSMs on the sensitivity of the simulated processes to vegetation density is essential to reduce their uncertainty and improve the representation of these effects. Here we present a novel benchmark system to assess model capacity in reproducing land surface-atmosphere energy exchanges modulated by vegetation density. Through a collaborative effort of different modeling groups, a consistent set of land surface energy fluxes and LAI dynamics has been generated from multiple LSMs, including JSBACH, JULES, ORCHIDEE, CLM4.5 and LPJ-GUESS. Relationships of interannual variations of modeled surface fluxes to LAI changes have been analyzed at global scale across different climatological gradients and compared with satellite-based products. A set of scoring metrics has been used to assess the overall model performances and a detailed analysis in the climate space has been provided to diagnose possible model errors associated to background conditions. Results have enabled us to identify model-specific strengths and deficiencies. An overall best performing model does not emerge from the analyses. However, the comparison with other models that work better under certain metrics and conditions indicates that improvements are expected to be potentially achievable. A general amplification of the biophysical processes mediated by vegetation is found across the different land surface schemes. Grasslands are characterized by an underestimated year-to-year variability of LAI in cold climates

  4. IASI's sensitivity to near-surface carbon monoxide (CO): Theoretical analyses and retrievals on test cases

    Science.gov (United States)

    Bauduin, Sophie; Clarisse, Lieven; Theunissen, Michael; George, Maya; Hurtmans, Daniel; Clerbaux, Cathy; Coheur, Pierre-François

    2017-03-01

    Separating concentrations of carbon monoxide (CO) in the boundary layer from the rest of the atmosphere with nadir satellite measurements is of particular importance to differentiate emission from transport. Although thermal infrared (TIR) satellite sounders are considered to have limited sensitivity to the composition of the near-surface atmosphere, previous studies show that they can provide information on CO close to the ground in case of high thermal contrast. In this work we investigate the capability of IASI (Infrared Atmospheric Sounding Interferometer) to retrieve near-surface CO concentrations, and we quantitatively assess the influence of thermal contrast on such retrievals. We present a 3-part analysis, which relies on both theoretical forward simulations and retrievals on real data, performed for a large range of negative and positive thermal contrast situations. First, we derive theoretically the IASI detection threshold of CO enhancement in the boundary layer, and we assess its dependence on thermal contrast. Then, using the optimal estimation formalism, we quantify the role of thermal contrast on the error budget and information content of near-surface CO retrievals. We demonstrate that, contrary to what is usually accepted, large negative thermal contrast values (ground cooler than air) lead to a better decorrelation between CO concentrations in the low and the high troposphere than large positive thermal contrast (ground warmer than the air). In the last part of the paper we use Mexico City and Barrow as test cases to contrast our theoretical predictions with real retrievals, and to assess the accuracy of IASI surface CO retrievals through comparisons to ground-based in-situ measurements.

  5. Experimental Design for Sensitivity Analysis of Simulation Models

    NARCIS (Netherlands)

    Kleijnen, J.P.C.

    2001-01-01

    This introductory tutorial gives a survey on the use of statistical designs for what if-or sensitivity analysis in simulation.This analysis uses regression analysis to approximate the input/output transformation that is implied by the simulation model; the resulting regression model is also known as

  6. Sensitivity analysis of a greedy heuristic for knapsack problems

    NARCIS (Netherlands)

    Ghosh, D; Chakravarti, N; Sierksma, G

    2006-01-01

    In this paper, we carry out parametric analysis as well as a tolerance limit based sensitivity analysis of a greedy heuristic for two knapsack problems-the 0-1 knapsack problem and the subset sum problem. We carry out the parametric analysis based on all problem parameters. In the tolerance limit

  7. Sensitivity analysis of numerical solutions for environmental fluid problems

    International Nuclear Information System (INIS)

    Tanaka, Nobuatsu; Motoyama, Yasunori

    2003-01-01

    In this study, we present a new numerical method to quantitatively analyze the error of numerical solutions by using the sensitivity analysis. If a reference case of typical parameters is one calculated with the method, no additional calculation is required to estimate the results of the other numerical parameters such as more detailed solutions. Furthermore, we can estimate the strict solution from the sensitivity analysis results and can quantitatively evaluate the reliability of the numerical solution by calculating the numerical error. (author)

  8. Analysis of gravity data using trend surfaces

    Science.gov (United States)

    Asimopolos, Natalia-Silvia; Asimopolos, Laurentiu

    2013-04-01

    In this paper we have developed algorithms and related software programs for calculating of trend surfaces of higher order. These methods of analysis of trends, like mobile media applications are filtration systems for geophysical data in surface. In particular we presented few case studies for gravity data and gravity maps. Analysis with polynomial trend surfaces contributes to the recognition, isolation and measurement of trends that can be represented by surfaces or hyper-surfaces (in several sizes), thus achieving a separation in regional variations and local variations. This separation is achieved by adjusting the trend function at different values. Trend surfaces using the regression analysis satisfy the criterion of least squares. The difference between the surface of trend and the observed value in a certain point is the residual value. Residual sum of squares of these values should be minimal as the criterion of least squares. The trend surface is considered as regional or large-scale and the residual value will be regarded as local or small-scale component. Removing the regional trend has the effect of highlighting local components represented by residual values. Surface analysis and hyper-surfaces principles are applied to the surface trend and any number of dimensions. For hyper-surfaces we can work with polynomial functions with four or more variables (three variables of space and other variables for interest parameters) that have great importance in some applications. In the paper we presented the mathematical developments about generalized trend surfaces and case studies about gravimetric data. The trend surfaces have the great advantage that the effect of regional anomalies can be expressed as analytic functions. These tendency surfaces allows subsequent mathematical processing and interesting generalizations, with great advantage to work with polynomial functions compared with the original discrete data. For gravity data we estimate the depth of

  9. Behavioral metabolomics analysis identifies novel neurochemical signatures in methamphetamine sensitization

    Science.gov (United States)

    Adkins, Daniel E.; McClay, Joseph L.; Vunck, Sarah A.; Batman, Angela M.; Vann, Robert E.; Clark, Shaunna L.; Souza, Renan P.; Crowley, James J.; Sullivan, Patrick F.; van den Oord, Edwin J.C.G.; Beardsley, Patrick M.

    2014-01-01

    Behavioral sensitization has been widely studied in animal models and is theorized to reflect neural modifications associated with human psychostimulant addiction. While the mesolimbic dopaminergic pathway is known to play a role, the neurochemical mechanisms underlying behavioral sensitization remain incompletely understood. In the present study, we conducted the first metabolomics analysis to globally characterize neurochemical differences associated with behavioral sensitization. Methamphetamine-induced sensitization measures were generated by statistically modeling longitudinal activity data for eight inbred strains of mice. Subsequent to behavioral testing, nontargeted liquid and gas chromatography-mass spectrometry profiling was performed on 48 brain samples, yielding 301 metabolite levels per sample after quality control. Association testing between metabolite levels and three primary dimensions of behavioral sensitization (total distance, stereotypy and margin time) showed four robust, significant associations at a stringent metabolome-wide significance threshold (false discovery rate < 0.05). Results implicated homocarnosine, a dipeptide of GABA and histidine, in total distance sensitization, GABA metabolite 4-guanidinobutanoate and pantothenate in stereotypy sensitization, and myo-inositol in margin time sensitization. Secondary analyses indicated that these associations were independent of concurrent methamphetamine levels and, with the exception of the myo-inositol association, suggest a mechanism whereby strain-based genetic variation produces specific baseline neurochemical differences that substantially influence the magnitude of MA-induced sensitization. These findings demonstrate the utility of mouse metabolomics for identifying novel biomarkers, and developing more comprehensive neurochemical models, of psychostimulant sensitization. PMID:24034544

  10. Resonant characteristics and sensitivity dependency on the contact surface in QCM-micropillar-based system of coupled resonator sensors

    International Nuclear Information System (INIS)

    Kashan, M A M; Kalavally, V; Ramakrishnan, N; Lee, H W

    2016-01-01

    We report the characteristics and sensitivity dependence over the contact surface in coupled resonating sensors (CRSs) made of high aspect ratio resonant micropillars attached to a quartz crystal microbalance (QCM). Through experiments and simulation, we observed that when the pillars of resonant heights were placed in maximum displacement regions the resonance frequency of the QCM increased following the coupled resonance characteristics, as the pillar offered elastic loading to the QCM surface. However, the same pillars when placed in relatively lower displacement regions, in spite of their resonant dimension, offered inertial loading and resulted in a decrease in QCM resonance frequency, as the displacement amplitude was insufficient to couple the vibrations from the QCM to the pillars. Accordingly, we discovered that the coupled resonance characteristics not only depend on the resonant structure dimensions but also on the contact regions in the acoustic device. Further analysis revealed that acoustic pressure at the contact surface also influences the resonance frequency characteristics and sensitivity of the CRS. To demonstrate the significance of the present finding for sensing applications, humidity sensing is considered as the example measurand. When a sensing medium made of resonant SU-8 pillars was placed in a maximum displacement region on a QCM surface, the sensitivity increased by 14 times in comparison to a resonant sensing medium placed in a lower displacement region of a QCM surface. (paper)

  11. Risk and sensitivity analysis in relation to external events

    International Nuclear Information System (INIS)

    Alzbutas, R.; Urbonas, R.; Augutis, J.

    2001-01-01

    This paper presents risk and sensitivity analysis of external events impacts on the safe operation in general and in particular the Ignalina Nuclear Power Plant safety systems. Analysis is based on the deterministic and probabilistic assumptions and assessment of the external hazards. The real statistic data are used as well as initial external event simulation. The preliminary screening criteria are applied. The analysis of external event impact on the NPP safe operation, assessment of the event occurrence, sensitivity analysis, and recommendations for safety improvements are performed for investigated external hazards. Such events as aircraft crash, extreme rains and winds, forest fire and flying parts of the turbine are analysed. The models are developed and probabilities are calculated. As an example for sensitivity analysis the model of aircraft impact is presented. The sensitivity analysis takes into account the uncertainty features raised by external event and its model. Even in case when the external events analysis show rather limited danger, the sensitivity analysis can determine the highest influence causes. These possible variations in future can be significant for safety level and risk based decisions. Calculations show that external events cannot significantly influence the safety level of the Ignalina NPP operation, however the events occurrence and propagation can be sufficiently uncertain.(author)

  12. High sensitivity analysis of atmospheric gas elements

    International Nuclear Information System (INIS)

    Miwa, Shiro; Nomachi, Ichiro; Kitajima, Hideo

    2006-01-01

    We have investigated the detection limit of H, C and O in Si, GaAs and InP using a Cameca IMS-4f instrument equipped with a modified vacuum system to improve the detection limit with a lower sputtering rate We found that the detection limits for H, O and C are improved by employing a primary ion bombardment before the analysis. Background levels of 1 x 10 17 atoms/cm 3 for H, of 3 x 10 16 atoms/cm 3 for C and of 2 x 10 16 atoms/cm 3 for O could be achieved in silicon with a sputtering rate of 2 nm/s after a primary ion bombardment for 160 h. We also found that the use of a 20 K He cryo-panel near the sample holder was effective for obtaining better detection limits in a shorter time, although the final detection limits using the panel are identical to those achieved without it

  13. High sensitivity analysis of atmospheric gas elements

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, Shiro [Materials Analysis Lab., Sony Corporation, 4-16-1 Okata, Atsugi 243-0021 (Japan)]. E-mail: Shiro.Miwa@jp.sony.com; Nomachi, Ichiro [Materials Analysis Lab., Sony Corporation, 4-16-1 Okata, Atsugi 243-0021 (Japan); Kitajima, Hideo [Nanotechnos Corp., 5-4-30 Nishihashimoto, Sagamihara 229-1131 (Japan)

    2006-07-30

    We have investigated the detection limit of H, C and O in Si, GaAs and InP using a Cameca IMS-4f instrument equipped with a modified vacuum system to improve the detection limit with a lower sputtering rate We found that the detection limits for H, O and C are improved by employing a primary ion bombardment before the analysis. Background levels of 1 x 10{sup 17} atoms/cm{sup 3} for H, of 3 x 10{sup 16} atoms/cm{sup 3} for C and of 2 x 10{sup 16} atoms/cm{sup 3} for O could be achieved in silicon with a sputtering rate of 2 nm/s after a primary ion bombardment for 160 h. We also found that the use of a 20 K He cryo-panel near the sample holder was effective for obtaining better detection limits in a shorter time, although the final detection limits using the panel are identical to those achieved without it.

  14. Sensitivity Analysis of BLISK Airfoil Wear †

    Directory of Open Access Journals (Sweden)

    Andreas Kellersmann

    2018-05-01

    Full Text Available The decreasing performance of jet engines during operation is a major concern for airlines and maintenance companies. Among other effects, the erosion of high-pressure compressor (HPC blades is a critical one and leads to a changed aerodynamic behavior, and therefore to a change in performance. The maintenance of BLISKs (blade-integrated-disks is especially challenging because the blade arrangement cannot be changed and individual blades cannot be replaced. Thus, coupled deteriorated blades have a complex aerodynamic behavior which can have a stronger influence on compressor performance than a conventional HPC. To ensure effective maintenance for BLISKs, the impact of coupled misshaped blades are the key factor. The present study addresses these effects on the aerodynamic performance of a first-stage BLISK of a high-pressure compressor. Therefore, a design of experiments (DoE is done to identify the geometric properties which lead to a reduction in performance. It is shown that the effect of coupled variances is dependent on the operating point. Based on the DoE analysis, the thickness-related parameters, the stagger angle, and the max. profile camber as coupled parameters are identified as the most important parameters for all operating points.

  15. Sensitivity analysis for matched pair analysis of binary data: From worst case to average case analysis.

    Science.gov (United States)

    Hasegawa, Raiden; Small, Dylan

    2017-12-01

    In matched observational studies where treatment assignment is not randomized, sensitivity analysis helps investigators determine how sensitive their estimated treatment effect is to some unmeasured confounder. The standard approach calibrates the sensitivity analysis according to the worst case bias in a pair. This approach will result in a conservative sensitivity analysis if the worst case bias does not hold in every pair. In this paper, we show that for binary data, the standard approach can be calibrated in terms of the average bias in a pair rather than worst case bias. When the worst case bias and average bias differ, the average bias interpretation results in a less conservative sensitivity analysis and more power. In many studies, the average case calibration may also carry a more natural interpretation than the worst case calibration and may also allow researchers to incorporate additional data to establish an empirical basis with which to calibrate a sensitivity analysis. We illustrate this with a study of the effects of cellphone use on the incidence of automobile accidents. Finally, we extend the average case calibration to the sensitivity analysis of confidence intervals for attributable effects. © 2017, The International Biometric Society.

  16. Combining inkjet printing and sol-gel chemistry for making pH-sensitive surfaces.

    Science.gov (United States)

    Orsi, Gianni; De Maria, Carmelo; Montemurro, Francesca; Chauhan, Veeren M; Aylott, Jonathan W; Vozzi, Giovanni

    2015-01-01

    Today biomedical sciences are experiencing the importance of imaging biological parameters with luminescence methods. Studying 2D pH distribution with those methods allows building knowledge about complex cellular processes. Immobilizing pH sensitive nanoparticles inside hydrogel matrixes, in order to guarantee a proper SNR, could easily make stable and biocompatible 2D sensors. Inkjet printing is also well known as tool for printing images onto porous surfaces. Recently it has been used as a free-form fabrication method for building three-dimensional parts, and now is being explored as a way of printing electrical and optical devices. Inkjet printing was used either as a rapid prototyping method for custom biosensors. Sol-gel method is naturally bound with inkjet, because the picoliter-sized ink droplets evaporate quickly, thus allowing quick sol-gel transitions on the printed surface. In this work will be shown how to merge those technologies, in order to make a nanoparticles doped printable hydrogel, which could be used for making 2D/3D smart scaffolds able to monitor cell activities. An automated image analysis system was developed in order to quickly have the pH measurements from pH nanosensors fluorescence images.

  17. The sensitivity of biological finite element models to the resolution of surface geometry: a case study of crocodilian crania

    Directory of Open Access Journals (Sweden)

    Matthew R. McCurry

    2015-06-01

    Full Text Available The reliability of finite element analysis (FEA in biomechanical investigations depends upon understanding the influence of model assumptions. In producing finite element models, surface mesh resolution is influenced by the resolution of input geometry, and influences the resolution of the ensuing solid mesh used for numerical analysis. Despite a large number of studies incorporating sensitivity studies of the effects of solid mesh resolution there has not yet been any investigation into the effect of surface mesh resolution upon results in a comparative context. Here we use a dataset of crocodile crania to examine the effects of surface resolution on FEA results in a comparative context. Seven high-resolution surface meshes were each down-sampled to varying degrees while keeping the resulting number of solid elements constant. These models were then subjected to bite and shake load cases using finite element analysis. The results show that incremental decreases in surface resolution can result in fluctuations in strain magnitudes, but that it is possible to obtain stable results using lower resolution surface in a comparative FEA study. As surface mesh resolution links input geometry with the resulting solid mesh, the implication of these results is that low resolution input geometry and solid meshes may provide valid results in a comparative context.

  18. Application of Stochastic Sensitivity Analysis to Integrated Force Method

    Directory of Open Access Journals (Sweden)

    X. F. Wei

    2012-01-01

    Full Text Available As a new formulation in structural analysis, Integrated Force Method has been successfully applied to many structures for civil, mechanical, and aerospace engineering due to the accurate estimate of forces in computation. Right now, it is being further extended to the probabilistic domain. For the assessment of uncertainty effect in system optimization and identification, the probabilistic sensitivity analysis of IFM was further investigated in this study. A set of stochastic sensitivity analysis formulation of Integrated Force Method was developed using the perturbation method. Numerical examples are presented to illustrate its application. Its efficiency and accuracy were also substantiated with direct Monte Carlo simulations and the reliability-based sensitivity method. The numerical algorithm was shown to be readily adaptable to the existing program since the models of stochastic finite element and stochastic design sensitivity are almost identical.

  19. The EVEREST project: sensitivity analysis of geological disposal systems

    International Nuclear Information System (INIS)

    Marivoet, Jan; Wemaere, Isabelle; Escalier des Orres, Pierre; Baudoin, Patrick; Certes, Catherine; Levassor, Andre; Prij, Jan; Martens, Karl-Heinz; Roehlig, Klaus

    1997-01-01

    The main objective of the EVEREST project is the evaluation of the sensitivity of the radiological consequences associated with the geological disposal of radioactive waste to the different elements in the performance assessment. Three types of geological host formations are considered: clay, granite and salt. The sensitivity studies that have been carried out can be partitioned into three categories according to the type of uncertainty taken into account: uncertainty in the model parameters, uncertainty in the conceptual models and uncertainty in the considered scenarios. Deterministic as well as stochastic calculational approaches have been applied for the sensitivity analyses. For the analysis of the sensitivity to parameter values, the reference technique, which has been applied in many evaluations, is stochastic and consists of a Monte Carlo simulation followed by a linear regression. For the analysis of conceptual model uncertainty, deterministic and stochastic approaches have been used. For the analysis of uncertainty in the considered scenarios, mainly deterministic approaches have been applied

  20. Multiple predictor smoothing methods for sensitivity analysis: Description of techniques

    International Nuclear Information System (INIS)

    Storlie, Curtis B.; Helton, Jon C.

    2008-01-01

    The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (i) locally weighted regression (LOESS), (ii) additive models, (iii) projection pursuit regression, and (iv) recursive partitioning regression. Then, in the second and concluding part of this presentation, the indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present

  1. Multiple predictor smoothing methods for sensitivity analysis: Example results

    International Nuclear Information System (INIS)

    Storlie, Curtis B.; Helton, Jon C.

    2008-01-01

    The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described in the first part of this presentation: (i) locally weighted regression (LOESS), (ii) additive models, (iii) projection pursuit regression, and (iv) recursive partitioning regression. In this, the second and concluding part of the presentation, the indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present

  2. Carbon dioxide capture processes: Simulation, design and sensitivity analysis

    DEFF Research Database (Denmark)

    Zaman, Muhammad; Lee, Jay Hyung; Gani, Rafiqul

    2012-01-01

    equilibrium and associated property models are used. Simulations are performed to investigate the sensitivity of the process variables to change in the design variables including process inputs and disturbances in the property model parameters. Results of the sensitivity analysis on the steady state...... performance of the process to the L/G ratio to the absorber, CO2 lean solvent loadings, and striper pressure are presented in this paper. Based on the sensitivity analysis process optimization problems have been defined and solved and, a preliminary control structure selection has been made.......Carbon dioxide is the main greenhouse gas and its major source is combustion of fossil fuels for power generation. The objective of this study is to carry out the steady-state sensitivity analysis for chemical absorption of carbon dioxide capture from flue gas using monoethanolamine solvent. First...

  3. Global sensitivity analysis in stochastic simulators of uncertain reaction networks.

    Science.gov (United States)

    Navarro Jimenez, M; Le Maître, O P; Knio, O M

    2016-12-28

    Stochastic models of chemical systems are often subjected to uncertainties in kinetic parameters in addition to the inherent random nature of their dynamics. Uncertainty quantification in such systems is generally achieved by means of sensitivity analyses in which one characterizes the variability with the uncertain kinetic parameters of the first statistical moments of model predictions. In this work, we propose an original global sensitivity analysis method where the parametric and inherent variability sources are both treated through Sobol's decomposition of the variance into contributions from arbitrary subset of uncertain parameters and stochastic reaction channels. The conceptual development only assumes that the inherent and parametric sources are independent, and considers the Poisson processes in the random-time-change representation of the state dynamics as the fundamental objects governing the inherent stochasticity. A sampling algorithm is proposed to perform the global sensitivity analysis, and to estimate the partial variances and sensitivity indices characterizing the importance of the various sources of variability and their interactions. The birth-death and Schlögl models are used to illustrate both the implementation of the algorithm and the richness of the proposed analysis method. The output of the proposed sensitivity analysis is also contrasted with a local derivative-based sensitivity analysis method classically used for this type of systems.

  4. Sensitivity Analysis for Urban Drainage Modeling Using Mutual Information

    Directory of Open Access Journals (Sweden)

    Chuanqi Li

    2014-11-01

    Full Text Available The intention of this paper is to evaluate the sensitivity of the Storm Water Management Model (SWMM output to its input parameters. A global parameter sensitivity analysis is conducted in order to determine which parameters mostly affect the model simulation results. Two different methods of sensitivity analysis are applied in this study. The first one is the partial rank correlation coefficient (PRCC which measures nonlinear but monotonic relationships between model inputs and outputs. The second one is based on the mutual information which provides a general measure of the strength of the non-monotonic association between two variables. Both methods are based on the Latin Hypercube Sampling (LHS of the parameter space, and thus the same datasets can be used to obtain both measures of sensitivity. The utility of the PRCC and the mutual information analysis methods are illustrated by analyzing a complex SWMM model. The sensitivity analysis revealed that only a few key input variables are contributing significantly to the model outputs; PRCCs and mutual information are calculated and used to determine and rank the importance of these key parameters. This study shows that the partial rank correlation coefficient and mutual information analysis can be considered effective methods for assessing the sensitivity of the SWMM model to the uncertainty in its input parameters.

  5. Global sensitivity analysis in stochastic simulators of uncertain reaction networks

    KAUST Repository

    Navarro, María

    2016-12-26

    Stochastic models of chemical systems are often subjected to uncertainties in kinetic parameters in addition to the inherent random nature of their dynamics. Uncertainty quantification in such systems is generally achieved by means of sensitivity analyses in which one characterizes the variability with the uncertain kinetic parameters of the first statistical moments of model predictions. In this work, we propose an original global sensitivity analysis method where the parametric and inherent variability sources are both treated through Sobol’s decomposition of the variance into contributions from arbitrary subset of uncertain parameters and stochastic reaction channels. The conceptual development only assumes that the inherent and parametric sources are independent, and considers the Poisson processes in the random-time-change representation of the state dynamics as the fundamental objects governing the inherent stochasticity. A sampling algorithm is proposed to perform the global sensitivity analysis, and to estimate the partial variances and sensitivity indices characterizing the importance of the various sources of variability and their interactions. The birth-death and Schlögl models are used to illustrate both the implementation of the algorithm and the richness of the proposed analysis method. The output of the proposed sensitivity analysis is also contrasted with a local derivative-based sensitivity analysis method classically used for this type of systems.

  6. Calculating the sensitivity of wind turbine loads to wind inputs using response surfaces

    International Nuclear Information System (INIS)

    Rinker, Jennifer M.

    2016-01-01

    This paper presents a methodology to calculate wind turbine load sensitivities to turbulence parameters through the use of response surfaces. A response surface is a highdimensional polynomial surface that can be calibrated to any set of input/output data and then used to generate synthetic data at a low computational cost. Sobol sensitivity indices (SIs) can then be calculated with relative ease using the calibrated response surface. The proposed methodology is demonstrated by calculating the total sensitivity of the maximum blade root bending moment of the WindPACT 5 MW reference model to four turbulence input parameters: a reference mean wind speed, a reference turbulence intensity, the Kaimal length scale, and a novel parameter reflecting the nonstationarity present in the inflow turbulence. The input/output data used to calibrate the response surface were generated for a previous project. The fit of the calibrated response surface is evaluated in terms of error between the model and the training data and in terms of the convergence. The Sobol SIs are calculated using the calibrated response surface, and the convergence is examined. The Sobol SIs reveal that, of the four turbulence parameters examined in this paper, the variance caused by the Kaimal length scale and nonstationarity parameter are negligible. Thus, the findings in this paper represent the first systematic evidence that stochastic wind turbine load response statistics can be modeled purely by mean wind wind speed and turbulence intensity. (paper)

  7. Allergen Sensitization Pattern by Sex: A Cluster Analysis in Korea.

    Science.gov (United States)

    Ohn, Jungyoon; Paik, Seung Hwan; Doh, Eun Jin; Park, Hyun-Sun; Yoon, Hyun-Sun; Cho, Soyun

    2017-12-01

    Allergens tend to sensitize simultaneously. Etiology of this phenomenon has been suggested to be allergen cross-reactivity or concurrent exposure. However, little is known about specific allergen sensitization patterns. To investigate the allergen sensitization characteristics according to gender. Multiple allergen simultaneous test (MAST) is widely used as a screening tool for detecting allergen sensitization in dermatologic clinics. We retrospectively reviewed the medical records of patients with MAST results between 2008 and 2014 in our Department of Dermatology. A cluster analysis was performed to elucidate the allergen-specific immunoglobulin (Ig)E cluster pattern. The results of MAST (39 allergen-specific IgEs) from 4,360 cases were analyzed. By cluster analysis, 39items were grouped into 8 clusters. Each cluster had characteristic features. When compared with female, the male group tended to be sensitized more frequently to all tested allergens, except for fungus allergens cluster. The cluster and comparative analysis results demonstrate that the allergen sensitization is clustered, manifesting allergen similarity or co-exposure. Only the fungus cluster allergens tend to sensitize female group more frequently than male group.

  8. A general first-order global sensitivity analysis method

    International Nuclear Information System (INIS)

    Xu Chonggang; Gertner, George Zdzislaw

    2008-01-01

    Fourier amplitude sensitivity test (FAST) is one of the most popular global sensitivity analysis techniques. The main mechanism of FAST is to assign each parameter with a characteristic frequency through a search function. Then, for a specific parameter, the variance contribution can be singled out of the model output by the characteristic frequency. Although FAST has been widely applied, there are two limitations: (1) the aliasing effect among parameters by using integer characteristic frequencies and (2) the suitability for only models with independent parameters. In this paper, we synthesize the improvement to overcome the aliasing effect limitation [Tarantola S, Gatelli D, Mara TA. Random balance designs for the estimation of first order global sensitivity indices. Reliab Eng Syst Safety 2006; 91(6):717-27] and the improvement to overcome the independence limitation [Xu C, Gertner G. Extending a global sensitivity analysis technique to models with correlated parameters. Comput Stat Data Anal 2007, accepted for publication]. In this way, FAST can be a general first-order global sensitivity analysis method for linear/nonlinear models with as many correlated/uncorrelated parameters as the user specifies. We apply the general FAST to four test cases with correlated parameters. The results show that the sensitivity indices derived by the general FAST are in good agreement with the sensitivity indices derived by the correlation ratio method, which is a non-parametric method for models with correlated parameters

  9. Sensitivity analysis of simulated SOA loadings using a variance-based statistical approach: SENSITIVITY ANALYSIS OF SOA

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, Manish [Pacific Northwest National Laboratory, Richland Washington USA; Zhao, Chun [Pacific Northwest National Laboratory, Richland Washington USA; Easter, Richard C. [Pacific Northwest National Laboratory, Richland Washington USA; Qian, Yun [Pacific Northwest National Laboratory, Richland Washington USA; Zelenyuk, Alla [Pacific Northwest National Laboratory, Richland Washington USA; Fast, Jerome D. [Pacific Northwest National Laboratory, Richland Washington USA; Liu, Ying [Pacific Northwest National Laboratory, Richland Washington USA; Zhang, Qi [Department of Environmental Toxicology, University of California Davis, California USA; Guenther, Alex [Department of Earth System Science, University of California, Irvine California USA

    2016-04-08

    We investigate the sensitivity of secondary organic aerosol (SOA) loadings simulated by a regional chemical transport model to 7 selected tunable model parameters: 4 involving emissions of anthropogenic and biogenic volatile organic compounds, anthropogenic semi-volatile and intermediate volatility organics (SIVOCs), and NOx, 2 involving dry deposition of SOA precursor gases, and one involving particle-phase transformation of SOA to low volatility. We adopt a quasi-Monte Carlo sampling approach to effectively sample the high-dimensional parameter space, and perform a 250 member ensemble of simulations using a regional model, accounting for some of the latest advances in SOA treatments based on our recent work. We then conduct a variance-based sensitivity analysis using the generalized linear model method to study the responses of simulated SOA loadings to the tunable parameters. Analysis of SOA variance from all 250 simulations shows that the volatility transformation parameter, which controls whether particle-phase transformation of SOA from semi-volatile SOA to non-volatile is on or off, is the dominant contributor to variance of simulated surface-level daytime SOA (65% domain average contribution). We also split the simulations into 2 subsets of 125 each, depending on whether the volatility transformation is turned on/off. For each subset, the SOA variances are dominated by the parameters involving biogenic VOC and anthropogenic SIVOC emissions. Furthermore, biogenic VOC emissions have a larger contribution to SOA variance when the SOA transformation to non-volatile is on, while anthropogenic SIVOC emissions have a larger contribution when the transformation is off. NOx contributes less than 4.3% to SOA variance, and this low contribution is mainly attributed to dominance of intermediate to high NOx conditions throughout the simulated domain. The two parameters related to dry deposition of SOA precursor gases also have very low contributions to SOA variance

  10. Enhanced sensitivity of surface plasmon resonance phase-interrogation biosensor by using oblique deposited silver nanorods.

    Science.gov (United States)

    Chung, Hung-Yi; Chen, Chih-Chia; Wu, Pin Chieh; Tseng, Ming Lun; Lin, Wen-Chi; Chen, Chih-Wei; Chiang, Hai-Pang

    2014-01-01

    Sensitivity of surface plasmon resonance phase-interrogation biosensor is demonstrated to be enhanced by oblique deposited silver nanorods. Silver nanorods are thermally deposited on silver nanothin film by oblique angle deposition (OAD). The length of the nanorods can be tuned by controlling the deposition parameters of thermal deposition. By measuring the phase difference between the p and s waves of surface plasmon resonance heterodyne interferometer with different wavelength of incident light, we have demonstrated that maximum sensitivity of glucose detection down to 7.1 × 10(-8) refractive index units could be achieved with optimal deposition parameters of silver nanorods.

  11. On the sensitivity of mesoscale models to surface-layer parameterization constants

    Science.gov (United States)

    Garratt, J. R.; Pielke, R. A.

    1989-09-01

    The Colorado State University standard mesoscale model is used to evaluate the sensitivity of one-dimensional (1D) and two-dimensional (2D) fields to differences in surface-layer parameterization “constants”. Such differences reflect the range in the published values of the von Karman constant, Monin-Obukhov stability functions and the temperature roughness length at the surface. The sensitivity of 1D boundary-layer structure, and 2D sea-breeze intensity, is generally less than that found in published comparisons related to turbulence closure schemes generally.

  12. The observed sensitivity of the global hydrological cycle to changes in surface temperature

    International Nuclear Information System (INIS)

    Arkin, Phillip A; Janowiak, John; Smith, Thomas M; Sapiano, Mathew R P

    2010-01-01

    Climate models project large changes in global surface temperature in coming decades that are expected to be accompanied by significant changes in the global hydrological cycle. Validation of model simulations is essential to support their use in decision making, but observing the elements of the hydrological cycle is challenging, and model-independent global data sets exist only for precipitation. We compute the sensitivity of the global hydrological cycle to changes in surface temperature using available global precipitation data sets and compare the results against the sensitivities derived from model simulations of 20th century climate. The implications of the results for the global climate observing system are discussed.

  13. Methods and computer codes for probabilistic sensitivity and uncertainty analysis

    International Nuclear Information System (INIS)

    Vaurio, J.K.

    1985-01-01

    This paper describes the methods and applications experience with two computer codes that are now available from the National Energy Software Center at Argonne National Laboratory. The purpose of the SCREEN code is to identify a group of most important input variables of a code that has many (tens, hundreds) input variables with uncertainties, and do this without relying on judgment or exhaustive sensitivity studies. Purpose of the PROSA-2 code is to propagate uncertainties and calculate the distributions of interesting output variable(s) of a safety analysis code using response surface techniques, based on the same runs used for screening. Several applications are discussed, but the codes are generic, not tailored to any specific safety application code. They are compatible in terms of input/output requirements but also independent of each other, e.g., PROSA-2 can be used without first using SCREEN if a set of important input variables has first been selected by other methods. Also, although SCREEN can select cases to be run (by random sampling), a user can select cases by other methods if he so prefers, and still use the rest of SCREEN for identifying important input variables

  14. Sensitivity study of CFD turbulent models for natural convection analysis

    International Nuclear Information System (INIS)

    Yu sun, Park

    2007-01-01

    The buoyancy driven convective flow fields are steady circulatory flows which were made between surfaces maintained at two fixed temperatures. They are ubiquitous in nature and play an important role in many engineering applications. Application of a natural convection can reduce the costs and efforts remarkably. This paper focuses on the sensitivity study of turbulence analysis using CFD (Computational Fluid Dynamics) for a natural convection in a closed rectangular cavity. Using commercial CFD code, FLUENT and various turbulent models were applied to the turbulent flow. Results from each CFD model will be compared each other in the viewpoints of grid resolution and flow characteristics. It has been showed that: -) obtaining general flow characteristics is possible with relatively coarse grid; -) there is no significant difference between results from finer grid resolutions than grid with y + + is defined as y + = ρ*u*y/μ, u being the wall friction velocity, y being the normal distance from the center of the cell to the wall, ρ and μ being respectively the fluid density and the fluid viscosity; -) the K-ε models show a different flow characteristic from K-ω models or from the Reynolds Stress Model (RSM); and -) the y + parameter is crucial for the selection of the appropriate turbulence model to apply within the simulation

  15. PHOTOGRAMMETRIC TECHNIQUES FOR ROAD SURFACE ANALYSIS

    Directory of Open Access Journals (Sweden)

    V. A. Knyaz

    2016-06-01

    Full Text Available The quality and condition of a road surface is of great importance for convenience and safety of driving. So the investigations of the behaviour of road materials in laboratory conditions and monitoring of existing roads are widely fulfilled for controlling a geometric parameters and detecting defects in the road surface. Photogrammetry as accurate non-contact measuring method provides powerful means for solving different tasks in road surface reconstruction and analysis. The range of dimensions concerned in road surface analysis can have great variation from tenths of millimetre to hundreds meters and more. So a set of techniques is needed to meet all requirements of road parameters estimation. Two photogrammetric techniques for road surface analysis are presented: for accurate measuring of road pavement and for road surface reconstruction based on imagery obtained from unmanned aerial vehicle. The first technique uses photogrammetric system based on structured light for fast and accurate surface 3D reconstruction and it allows analysing the characteristics of road texture and monitoring the pavement behaviour. The second technique provides dense 3D model road suitable for road macro parameters estimation.

  16. Global sensitivity analysis of computer models with functional inputs

    International Nuclear Information System (INIS)

    Iooss, Bertrand; Ribatet, Mathieu

    2009-01-01

    Global sensitivity analysis is used to quantify the influence of uncertain model inputs on the response variability of a numerical model. The common quantitative methods are appropriate with computer codes having scalar model inputs. This paper aims at illustrating different variance-based sensitivity analysis techniques, based on the so-called Sobol's indices, when some model inputs are functional, such as stochastic processes or random spatial fields. In this work, we focus on large cpu time computer codes which need a preliminary metamodeling step before performing the sensitivity analysis. We propose the use of the joint modeling approach, i.e., modeling simultaneously the mean and the dispersion of the code outputs using two interlinked generalized linear models (GLMs) or generalized additive models (GAMs). The 'mean model' allows to estimate the sensitivity indices of each scalar model inputs, while the 'dispersion model' allows to derive the total sensitivity index of the functional model inputs. The proposed approach is compared to some classical sensitivity analysis methodologies on an analytical function. Lastly, the new methodology is applied to an industrial computer code that simulates the nuclear fuel irradiation.

  17. SURFACE ENERGY BALANCE OVER ORANGE ORCHARD USING SURFACE RENEWAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Salvatore Barbagallo

    2009-12-01

    Full Text Available Reliable estimation of surface sensible and latent heat flux is the most important process to appraise energy and mass exchange among atmosphere and biosphere. In this study the surface energy fluxes were measured over an irrigated orange orchard during 2005-2008 monitoring periods using a Surface Renewal- Energy Balance approach. The experimental area is located in a representative orchard growing area of eastern Sicily (Italy. The performance of Surface Renewal (SR analysis for estimating sensible heat flux (H was analysed and evaluated in terms of correlation with H fluxes from the eddy covariance (EC method. Study revealed that the mean available energy (RN- G and latent heat flux (LE were of about 300 W m-2 and 237 W m-2, respectively, during dry periods and unstable-case atmospheric conditions. The estimated crop coefficient Kc values for the orchard crop averaged close to 0.80, which is considerably higher than previous FAO studies that found the value to be 0.65 for citrus with 70% of ground cover. The intercepted photosynthetically active radiation (LI PAR by the crop was measured and relationships between LAI and crop coefficient (Kc were established.

  18. A tool model for predicting atmospheric kinetics with sensitivity analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A package( a tool model) for program of predicting atmospheric chemical kinetics with sensitivity analysis is presented. The new direct method of calculating the first order sensitivity coefficients using sparse matrix technology to chemical kinetics is included in the tool model, it is only necessary to triangularize the matrix related to the Jacobian matrix of the model equation. The Gear type procedure is used to integrate amodel equation and its coupled auxiliary sensitivity coefficient equations. The FORTRAN subroutines of the model equation, the sensitivity coefficient equations, and their Jacobian analytical expressions are generated automatically from a chemical mechanism. The kinetic representation for the model equation and its sensitivity coefficient equations, and their Jacobian matrix is presented. Various FORTRAN subroutines in packages, such as SLODE, modified MA28, Gear package, with which the program runs in conjunction are recommended.The photo-oxidation of dimethyl disulfide is used for illustration.

  19. Sensitivity analysis of the nuclear data for MYRRHA reactor modelling

    International Nuclear Information System (INIS)

    Stankovskiy, Alexey; Van den Eynde, Gert; Cabellos, Oscar; Diez, Carlos J.; Schillebeeckx, Peter; Heyse, Jan

    2014-01-01

    A global sensitivity analysis of effective neutron multiplication factor k eff to the change of nuclear data library revealed that JEFF-3.2T2 neutron-induced evaluated data library produces closer results to ENDF/B-VII.1 than does JEFF-3.1.2. The analysis of contributions of individual evaluations into k eff sensitivity allowed establishing the priority list of nuclides for which uncertainties on nuclear data must be improved. Detailed sensitivity analysis has been performed for two nuclides from this list, 56 Fe and 238 Pu. The analysis was based on a detailed survey of the evaluations and experimental data. To track the origin of the differences in the evaluations and their impact on k eff , the reaction cross-sections and multiplicities in one evaluation have been substituted by the corresponding data from other evaluations. (authors)

  20. Analysis of surface with low energy ions

    International Nuclear Information System (INIS)

    Oliver, A.; Miranda, J.

    1989-01-01

    Nuclear techniques applied to element analysis presents different characteristics depending on projectile energy. It can seen observed than an energy (E ≅ 1 MeV) exists which separate two regions for which sensitivity, information analysis and resolution in detection are different. For this work, we describe for the energy region E ≤ 1 MeV, the advantage of the three most used techniques which are PIXE, RBS y RNR. (Author)

  1. Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model

    OpenAIRE

    Angelen, J. H.; Lenaerts, J. T. M.; Lhermitte, S.; Fettweis, X.; Kuipers Munneke, P.; Broeke, M. R.; Meijgaard, E.; Smeets, C. J. P. P.

    2012-01-01

    We present a sensitivity study of the surface mass balance (SMB) of the Greenland Ice Sheet, as modeled using a regional atmospheric climate model, to various parameter settings in the albedo scheme. The snow albedo scheme uses grain size as a prognostic variable and further depends on cloud cover, solar zenith angle and black carbon concentration. For the control experiment the overestimation of absorbed shortwave radiation (+6%) at the K-transect (west Greenland) for the period 2004–2009 is...

  2. A monolayer of hierarchical silver hemi-mesoparticles with tunable surface topographies for highly sensitive surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Zhu, Shuangmei; Fan, Chunzhen; Mao, Yanchao; Wang, Junqiao; He, Jinna; Liang, Erjun; Chao, Mingju

    2016-02-01

    We proposed a facile green synthesis system to synthesize large-scale Ag hemi-mesoparticles monolayer on Cu foil. Ag hemi-mesoparticles have different surface morphologies on their surfaces, including ridge-like, meatball-like, and fluffy-like shapes. In the reaction, silver nitrate was reduced by copper at room temperature in dimethyl sulfoxide via the galvanic displacement reaction. The different surface morphologies of the Ag hemi-mesoparticles were adjusted by changing the reaction time, and the hemi-mesoparticle surface formed fluffy-spherical nanoprotrusions at longer reaction time. At the same time, we explored the growth mechanism of silver hemi-mesoparticles with different surface morphologies. With 4-mercaptobenzoic acid as Raman probe molecules, the fluffy-like silver hemi-mesoparticles monolayer with the best activity of surface enhanced Raman scattering (SERS), the enhancement factor is up to 7.33 × 107 and the detection limit can reach 10-10M. SERS measurements demonstrate that these Ag hemi-mesoparticles can serve as sensitive SERS substrates. At the same time, using finite element method, the distribution of the localized electromagnetic field near the particle surface was simulated to verify the enhanced mechanism. This study helps us to understand the relationship between morphology Ag hemi-mesoparicles and the properties of SERS.

  3. Deterministic Local Sensitivity Analysis of Augmented Systems - I: Theory

    International Nuclear Information System (INIS)

    Cacuci, Dan G.; Ionescu-Bujor, Mihaela

    2005-01-01

    This work provides the theoretical foundation for the modular implementation of the Adjoint Sensitivity Analysis Procedure (ASAP) for large-scale simulation systems. The implementation of the ASAP commences with a selected code module and then proceeds by augmenting the size of the adjoint sensitivity system, module by module, until the entire system is completed. Notably, the adjoint sensitivity system for the augmented system can often be solved by using the same numerical methods used for solving the original, nonaugmented adjoint system, particularly when the matrix representation of the adjoint operator for the augmented system can be inverted by partitioning

  4. The identification of model effective dimensions using global sensitivity analysis

    International Nuclear Information System (INIS)

    Kucherenko, Sergei; Feil, Balazs; Shah, Nilay; Mauntz, Wolfgang

    2011-01-01

    It is shown that the effective dimensions can be estimated at reasonable computational costs using variance based global sensitivity analysis. Namely, the effective dimension in the truncation sense can be found by using the Sobol' sensitivity indices for subsets of variables. The effective dimension in the superposition sense can be estimated by using the first order effects and the total Sobol' sensitivity indices. The classification of some important classes of integrable functions based on their effective dimension is proposed. It is shown that it can be used for the prediction of the QMC efficiency. Results of numerical tests verify the prediction of the developed techniques.

  5. The identification of model effective dimensions using global sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kucherenko, Sergei, E-mail: s.kucherenko@ic.ac.u [CPSE, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Feil, Balazs [Department of Process Engineering, University of Pannonia, Veszprem (Hungary); Shah, Nilay [CPSE, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Mauntz, Wolfgang [Lehrstuhl fuer Anlagensteuerungstechnik, Fachbereich Chemietechnik, Universitaet Dortmund (Germany)

    2011-04-15

    It is shown that the effective dimensions can be estimated at reasonable computational costs using variance based global sensitivity analysis. Namely, the effective dimension in the truncation sense can be found by using the Sobol' sensitivity indices for subsets of variables. The effective dimension in the superposition sense can be estimated by using the first order effects and the total Sobol' sensitivity indices. The classification of some important classes of integrable functions based on their effective dimension is proposed. It is shown that it can be used for the prediction of the QMC efficiency. Results of numerical tests verify the prediction of the developed techniques.

  6. Application of Sensitivity Analysis in Design of Sustainable Buildings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Brohus, Henrik; Rasmussen, Henrik

    2009-01-01

    satisfies the design objectives and criteria. In the design of sustainable buildings, it is beneficial to identify the most important design parameters in order to more efficiently develop alternative design solutions or reach optimized design solutions. Sensitivity analyses make it possible to identify...... possible to influence the most important design parameters. A methodology of sensitivity analysis is presented and an application example is given for design of an office building in Denmark....

  7. Sensitivity Analysis of the Integrated Medical Model for ISS Programs

    Science.gov (United States)

    Goodenow, D. A.; Myers, J. G.; Arellano, J.; Boley, L.; Garcia, Y.; Saile, L.; Walton, M.; Kerstman, E.; Reyes, D.; Young, M.

    2016-01-01

    Sensitivity analysis estimates the relative contribution of the uncertainty in input values to the uncertainty of model outputs. Partial Rank Correlation Coefficient (PRCC) and Standardized Rank Regression Coefficient (SRRC) are methods of conducting sensitivity analysis on nonlinear simulation models like the Integrated Medical Model (IMM). The PRCC method estimates the sensitivity using partial correlation of the ranks of the generated input values to each generated output value. The partial part is so named because adjustments are made for the linear effects of all the other input values in the calculation of correlation between a particular input and each output. In SRRC, standardized regression-based coefficients measure the sensitivity of each input, adjusted for all the other inputs, on each output. Because the relative ranking of each of the inputs and outputs is used, as opposed to the values themselves, both methods accommodate the nonlinear relationship of the underlying model. As part of the IMM v4.0 validation study, simulations are available that predict 33 person-missions on ISS and 111 person-missions on STS. These simulated data predictions feed the sensitivity analysis procedures. The inputs to the sensitivity procedures include the number occurrences of each of the one hundred IMM medical conditions generated over the simulations and the associated IMM outputs: total quality time lost (QTL), number of evacuations (EVAC), and number of loss of crew lives (LOCL). The IMM team will report the results of using PRCC and SRRC on IMM v4.0 predictions of the ISS and STS missions created as part of the external validation study. Tornado plots will assist in the visualization of the condition-related input sensitivities to each of the main outcomes. The outcomes of this sensitivity analysis will drive review focus by identifying conditions where changes in uncertainty could drive changes in overall model output uncertainty. These efforts are an integral

  8. Sensitivity analysis of network DEA illustrated in branch banking

    OpenAIRE

    N. Avkiran

    2010-01-01

    Users of data envelopment analysis (DEA) often presume efficiency estimates to be robust. While traditional DEA has been exposed to various sensitivity studies, network DEA (NDEA) has so far escaped similar scrutiny. Thus, there is a need to investigate the sensitivity of NDEA, further compounded by the recent attention it has been receiving in literature. NDEA captures the underlying performance information found in a firm?s interacting divisions or sub-processes that would otherwise remain ...

  9. Sensitivity analysis of periodic errors in heterodyne interferometry

    International Nuclear Information System (INIS)

    Ganguly, Vasishta; Kim, Nam Ho; Kim, Hyo Soo; Schmitz, Tony

    2011-01-01

    Periodic errors in heterodyne displacement measuring interferometry occur due to frequency mixing in the interferometer. These nonlinearities are typically characterized as first- and second-order periodic errors which cause a cyclical (non-cumulative) variation in the reported displacement about the true value. This study implements an existing analytical periodic error model in order to identify sensitivities of the first- and second-order periodic errors to the input parameters, including rotational misalignments of the polarizing beam splitter and mixing polarizer, non-orthogonality of the two laser frequencies, ellipticity in the polarizations of the two laser beams, and different transmission coefficients in the polarizing beam splitter. A local sensitivity analysis is first conducted to examine the sensitivities of the periodic errors with respect to each input parameter about the nominal input values. Next, a variance-based approach is used to study the global sensitivities of the periodic errors by calculating the Sobol' sensitivity indices using Monte Carlo simulation. The effect of variation in the input uncertainty on the computed sensitivity indices is examined. It is seen that the first-order periodic error is highly sensitive to non-orthogonality of the two linearly polarized laser frequencies, while the second-order error is most sensitive to the rotational misalignment between the laser beams and the polarizing beam splitter. A particle swarm optimization technique is finally used to predict the possible setup imperfections based on experimentally generated values for periodic errors

  10. Sensitivity analysis of periodic errors in heterodyne interferometry

    Science.gov (United States)

    Ganguly, Vasishta; Kim, Nam Ho; Kim, Hyo Soo; Schmitz, Tony

    2011-03-01

    Periodic errors in heterodyne displacement measuring interferometry occur due to frequency mixing in the interferometer. These nonlinearities are typically characterized as first- and second-order periodic errors which cause a cyclical (non-cumulative) variation in the reported displacement about the true value. This study implements an existing analytical periodic error model in order to identify sensitivities of the first- and second-order periodic errors to the input parameters, including rotational misalignments of the polarizing beam splitter and mixing polarizer, non-orthogonality of the two laser frequencies, ellipticity in the polarizations of the two laser beams, and different transmission coefficients in the polarizing beam splitter. A local sensitivity analysis is first conducted to examine the sensitivities of the periodic errors with respect to each input parameter about the nominal input values. Next, a variance-based approach is used to study the global sensitivities of the periodic errors by calculating the Sobol' sensitivity indices using Monte Carlo simulation. The effect of variation in the input uncertainty on the computed sensitivity indices is examined. It is seen that the first-order periodic error is highly sensitive to non-orthogonality of the two linearly polarized laser frequencies, while the second-order error is most sensitive to the rotational misalignment between the laser beams and the polarizing beam splitter. A particle swarm optimization technique is finally used to predict the possible setup imperfections based on experimentally generated values for periodic errors.

  11. The surface analysis methods; Les methodes d`analyse des surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Deville, J.P. [Institut de Physique et Chimie, 67 - Strasbourg (France)

    1998-11-01

    Nowadays, there are a lot of surfaces analysis methods, each having its specificity, its qualities, its constraints (for instance vacuum) and its limits. Expensive in time and in investment, these methods have to be used deliberately. This article appeals to non specialists. It gives some elements of choice according to the studied information, the sensitivity, the use constraints or the answer to a precise question. After having recalled the fundamental principles which govern these analysis methods, based on the interaction between radiations (ultraviolet, X) or particles (ions, electrons) with matter, two methods will be more particularly described: the Auger electron spectroscopy (AES) and x-rays photoemission spectroscopy (ESCA or XPS). Indeed, they are the most widespread methods in laboratories, the easier for use and probably the most productive for the analysis of surface of industrial materials or samples submitted to treatments in aggressive media. (O.M.) 11 refs.

  12. MOVES sensitivity analysis update : Transportation Research Board Summer Meeting 2012 : ADC-20 Air Quality Committee

    Science.gov (United States)

    2012-01-01

    OVERVIEW OF PRESENTATION : Evaluation Parameters : EPAs Sensitivity Analysis : Comparison to Baseline Case : MOVES Sensitivity Run Specification : MOVES Sensitivity Input Parameters : Results : Uses of Study

  13. Sensitivity analysis of the reactor safety study. Final report

    International Nuclear Information System (INIS)

    Parkinson, W.J.; Rasmussen, N.C.; Hinkle, W.D.

    1979-01-01

    The Reactor Safety Study (RSS) or Wash 1400 developed a methodology estimating the public risk from light water nuclear reactors. In order to give further insights into this study, a sensitivity analysis has been performed to determine the significant contributors to risk for both the PWR and BWR. The sensitivity to variation of the point values of the failure probabilities reported in the RSS was determined for the safety systems identified therein, as well as for many of the generic classes from which individual failures contributed to system failures. Increasing as well as decreasing point values were considered. An analysis of the sensitivity to increasing uncertainty in system failure probabilities was also performed. The sensitivity parameters chosen were release category probabilities, core melt probability, and the risk parameters of early fatalities, latent cancers and total property damage. The latter three are adequate for describing all public risks identified in the RSS. The results indicate reductions of public risk by less than a factor of two for factor reductions in system or generic failure probabilities as high as one hundred. There also appears to be more benefit in monitoring the most sensitive systems to verify adherence to RSS failure rates than to backfitting present reactors. The sensitivity analysis results do indicate, however, possible benefits in reducing human error rates

  14. Rapid and sensitive detection of malachite green in aquaculture water by electrochemical preconcentration and surface-enhanced Raman scattering.

    Science.gov (United States)

    Xu, Kai-Xuan; Guo, Mei-Hong; Huang, Yu-Ping; Li, Xiao-Dong; Sun, Jian-Jun

    2018-04-01

    A highly sensitive and rapid method of in-situ surface-enhanced Raman spectroscopy (SERS) combining with electrochemical preconcentration (EP) in detecting malachite green (MG) in aquaculture water was established. Ag nanoparticles (AgNPs) were synthesized and spread onto the surface of gold electrodes after centrifuging to produce SERS-active substrates. After optimizing the pH values, preconcentration potentials and times, in-situ EP-SERS detection was carried out. A sensitive and rapid analysis of the low-concentration MG was accomplished within 200s and the limit of detection was 2.4 × 10 -16 M. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. SECTION 6.2 SURFACE TOPOGRAPHY ANALYSIS

    DEFF Research Database (Denmark)

    Seah, M. P.; De Chiffre, Leonardo

    2005-01-01

    Surface physical analysis, i.e. topography characterisation, encompasses measurement, visualisation, and quantification. This is critical for both component form and for surface finish at macro-, micro- and nano-scales. The principal methods of surface topography measurement are stylus profilometry......, optical scanning techniques, and scanning probe microscopy (SPM). These methods, based on acquisition of topography data from point by point scans, give quantitative information of heights with respect to position. Based on a different approach, the so-called integral methods produce parameters...

  16. Specifications for surface reaction analysis apparatus

    International Nuclear Information System (INIS)

    Teraoka, Yuden; Yoshigoe, Akitaka

    2001-03-01

    A surface reaction analysis apparatus was installed at the JAERI soft x-ray beamline in the SPring-8 as an experimental end-station for the study of surface chemistry. The apparatus is devoted to the study concerning the influence of translational kinetic energy of incident molecules to chemical reactions on solid surfaces with gas molecules. In order to achieve the research purpose, reactive molecular scattering experiments and photoemission spectroscopic measurements using synchrotron radiation are performed in that apparatus via a supersonic molecular beam generator, an electron energy analyzer and a quadrupole mass analyzer. The detail specifications for the apparatus are described in this report. (author)

  17. Sensitivity of surface temperature to radiative forcing by contrail cirrus in a radiative-mixing model

    Directory of Open Access Journals (Sweden)

    U. Schumann

    2017-11-01

    Full Text Available Earth's surface temperature sensitivity to radiative forcing (RF by contrail cirrus and the related RF efficacy relative to CO2 are investigated in a one-dimensional idealized model of the atmosphere. The model includes energy transport by shortwave (SW and longwave (LW radiation and by mixing in an otherwise fixed reference atmosphere (no other feedbacks. Mixing includes convective adjustment and turbulent diffusion, where the latter is related to the vertical component of mixing by large-scale eddies. The conceptual study shows that the surface temperature sensitivity to given contrail RF depends strongly on the timescales of energy transport by mixing and radiation. The timescales are derived for steady layered heating (ghost forcing and for a transient contrail cirrus case. The radiative timescales are shortest at the surface and shorter in the troposphere than in the mid-stratosphere. Without mixing, a large part of the energy induced into the upper troposphere by radiation due to contrails or similar disturbances gets lost to space before it can contribute to surface warming. Because of the different radiative forcing at the surface and at top of atmosphere (TOA and different radiative heating rate profiles in the troposphere, the local surface temperature sensitivity to stratosphere-adjusted RF is larger for SW than for LW contrail forcing. Without mixing, the surface energy budget is more important for surface warming than the TOA budget. Hence, surface warming by contrails is smaller than suggested by the net RF at TOA. For zero mixing, cooling by contrails cannot be excluded. This may in part explain low efficacy values for contrails found in previous global circulation model studies. Possible implications of this study are discussed. Since the results of this study are model dependent, they should be tested with a comprehensive climate model in the future.

  18. Sensitivity of Pseudomonas fluorescens to gamma irradiation following surface inoculations on romaine lettuce and baby spinach

    Science.gov (United States)

    Irradiation of fresh fruits and vegetables is a post-harvest intervention measure often used to inactivate pathogenic food-borne microbes. We evaluated the sensitivity of Pseudomonas fluorescens strains (2-79, Q8R1, Q287) to gamma irradiation following surface inoculations on romaine lettuce and spi...

  19. Application of sensitivity analysis for optimized piping support design

    International Nuclear Information System (INIS)

    Tai, K.; Nakatogawa, T.; Hisada, T.; Noguchi, H.; Ichihashi, I.; Ogo, H.

    1993-01-01

    The objective of this study was to see if recent developments in non-linear sensitivity analysis could be applied to the design of nuclear piping systems which use non-linear supports and to develop a practical method of designing such piping systems. In the study presented in this paper, the seismic response of a typical piping system was analyzed using a dynamic non-linear FEM and a sensitivity analysis was carried out. Then optimization for the design of the piping system supports was investigated, selecting the support location and yield load of the non-linear supports (bi-linear model) as main design parameters. It was concluded that the optimized design was a matter of combining overall system reliability with the achievement of an efficient damping effect from the non-linear supports. The analysis also demonstrated sensitivity factors are useful in the planning stage of support design. (author)

  20. Sensitivity and uncertainty analysis of the PATHWAY radionuclide transport model

    International Nuclear Information System (INIS)

    Otis, M.D.

    1983-01-01

    Procedures were developed for the uncertainty and sensitivity analysis of a dynamic model of radionuclide transport through human food chains. Uncertainty in model predictions was estimated by propagation of parameter uncertainties using a Monte Carlo simulation technique. Sensitivity of model predictions to individual parameters was investigated using the partial correlation coefficient of each parameter with model output. Random values produced for the uncertainty analysis were used in the correlation analysis for sensitivity. These procedures were applied to the PATHWAY model which predicts concentrations of radionuclides in foods grown in Nevada and Utah and exposed to fallout during the period of atmospheric nuclear weapons testing in Nevada. Concentrations and time-integrated concentrations of iodine-131, cesium-136, and cesium-137 in milk and other foods were investigated. 9 figs., 13 tabs

  1. Atmospheric sensitivity to land surface changes: comparing the impact of albedo, roughness, and evaporative resistance on near-surface air temperature using an idealized land model.

    Science.gov (United States)

    Lague, M. M.; Swann, A. L. S.; Bonan, G. B.

    2017-12-01

    Past studies have demonstrated how changes in vegetation can impact the atmosphere; however, it is often difficult to identify the exact physical pathway through which vegetation changes drive an atmospheric response. Surface properties (such as vegetation color, or height) control surface energy fluxes, which feed back on the atmosphere on both local and global scales by modifying temperatures, cloud cover, and energy gradients. Understanding how land surface properties influence energy fluxes is crucial for improving our understanding of how vegetation change - past, present, and future - impacts the atmosphere, global climate, and people. We explore the sensitivity of the atmosphere to perturbations of three land surface properties - albedo, roughness, and evaporative resistance - using an idealized land model coupled to an Earth System Model. We derive a relationship telling us how large a change in each surface property is required to drive a local 0.1 K change in 2m air temperature. Using this idealized framework, we are able to separate the influence on the atmosphere of each individual surface property. We demonstrate that the impact of each surface property on the atmosphere is spatially variable - that is, a similar change in vegetation can have different climate impacts if made in different locations. This analysis not only improves our understanding of how the land system can influence climate, but also provides us with a set of theoretical limits on the potential climate impact of arbitrary vegetation change (natural or anthropogenic).

  2. Discrete non-parametric kernel estimation for global sensitivity analysis

    International Nuclear Information System (INIS)

    Senga Kiessé, Tristan; Ventura, Anne

    2016-01-01

    This work investigates the discrete kernel approach for evaluating the contribution of the variance of discrete input variables to the variance of model output, via analysis of variance (ANOVA) decomposition. Until recently only the continuous kernel approach has been applied as a metamodeling approach within sensitivity analysis framework, for both discrete and continuous input variables. Now the discrete kernel estimation is known to be suitable for smoothing discrete functions. We present a discrete non-parametric kernel estimator of ANOVA decomposition of a given model. An estimator of sensitivity indices is also presented with its asymtotic convergence rate. Some simulations on a test function analysis and a real case study from agricultural have shown that the discrete kernel approach outperforms the continuous kernel one for evaluating the contribution of moderate or most influential discrete parameters to the model output. - Highlights: • We study a discrete kernel estimation for sensitivity analysis of a model. • A discrete kernel estimator of ANOVA decomposition of the model is presented. • Sensitivity indices are calculated for discrete input parameters. • An estimator of sensitivity indices is also presented with its convergence rate. • An application is realized for improving the reliability of environmental models.

  3. Sensitivity analysis for missing data in regulatory submissions.

    Science.gov (United States)

    Permutt, Thomas

    2016-07-30

    The National Research Council Panel on Handling Missing Data in Clinical Trials recommended that sensitivity analyses have to be part of the primary reporting of findings from clinical trials. Their specific recommendations, however, seem not to have been taken up rapidly by sponsors of regulatory submissions. The NRC report's detailed suggestions are along rather different lines than what has been called sensitivity analysis in the regulatory setting up to now. Furthermore, the role of sensitivity analysis in regulatory decision-making, although discussed briefly in the NRC report, remains unclear. This paper will examine previous ideas of sensitivity analysis with a view to explaining how the NRC panel's recommendations are different and possibly better suited to coping with present problems of missing data in the regulatory setting. It will also discuss, in more detail than the NRC report, the relevance of sensitivity analysis to decision-making, both for applicants and for regulators. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  4. Sobol' sensitivity analysis for stressor impacts on honeybee ...

    Science.gov (United States)

    We employ Monte Carlo simulation and nonlinear sensitivity analysis techniques to describe the dynamics of a bee exposure model, VarroaPop. Daily simulations are performed of hive population trajectories, taking into account queen strength, foraging success, mite impacts, weather, colony resources, population structure, and other important variables. This allows us to test the effects of defined pesticide exposure scenarios versus controlled simulations that lack pesticide exposure. The daily resolution of the model also allows us to conditionally identify sensitivity metrics. We use the variancebased global decomposition sensitivity analysis method, Sobol’, to assess firstand secondorder parameter sensitivities within VarroaPop, allowing us to determine how variance in the output is attributed to each of the input variables across different exposure scenarios. Simulations with VarroaPop indicate queen strength, forager life span and pesticide toxicity parameters are consistent, critical inputs for colony dynamics. Further analysis also reveals that the relative importance of these parameters fluctuates throughout the simulation period according to the status of other inputs. Our preliminary results show that model variability is conditional and can be attributed to different parameters depending on different timescales. By using sensitivity analysis to assess model output and variability, calibrations of simulation models can be better informed to yield more

  5. Variance estimation for sensitivity analysis of poverty and inequality measures

    Directory of Open Access Journals (Sweden)

    Christian Dudel

    2017-04-01

    Full Text Available Estimates of poverty and inequality are often based on application of a single equivalence scale, despite the fact that a large number of different equivalence scales can be found in the literature. This paper describes a framework for sensitivity analysis which can be used to account for the variability of equivalence scales and allows to derive variance estimates of results of sensitivity analysis. Simulations show that this method yields reliable estimates. An empirical application reveals that accounting for both variability of equivalence scales and sampling variance leads to confidence intervals which are wide.

  6. Sensitivity analysis of water consumption in an office building

    Science.gov (United States)

    Suchacek, Tomas; Tuhovcak, Ladislav; Rucka, Jan

    2018-02-01

    This article deals with sensitivity analysis of real water consumption in an office building. During a long-term real study, reducing of pressure in its water connection was simulated. A sensitivity analysis of uneven water demand was conducted during working time at various provided pressures and at various time step duration. Correlations between maximal coefficients of water demand variation during working time and provided pressure were suggested. The influence of provided pressure in the water connection on mean coefficients of water demand variation was pointed out, altogether for working hours of all days and separately for days with identical working hours.

  7. Probabilistic and sensitivity analysis of Botlek Bridge structures

    Directory of Open Access Journals (Sweden)

    Králik Juraj

    2017-01-01

    Full Text Available This paper deals with the probabilistic and sensitivity analysis of the largest movable lift bridge of the world. The bridge system consists of six reinforced concrete pylons and two steel decks 4000 tons weight each connected through ropes with counterweights. The paper focuses the probabilistic and sensitivity analysis as the base of dynamic study in design process of the bridge. The results had a high importance for practical application and design of the bridge. The model and resistance uncertainties were taken into account in LHS simulation method.

  8. Applying DEA sensitivity analysis to efficiency measurement of Vietnamese universities

    Directory of Open Access Journals (Sweden)

    Thi Thanh Huyen Nguyen

    2015-11-01

    Full Text Available The primary purpose of this study is to measure the technical efficiency of 30 doctorate-granting universities, the universities or the higher education institutes with PhD training programs, in Vietnam, applying the sensitivity analysis of data envelopment analysis (DEA. The study uses eight sets of input-output specifications using the replacement as well as aggregation/disaggregation of variables. The measurement results allow us to examine the sensitivity of the efficiency of these universities with the sets of variables. The findings also show the impact of variables on their efficiency and its “sustainability”.

  9. Quantitative XPS analysis of high Tc superconductor surfaces

    International Nuclear Information System (INIS)

    Jablonski, A.; Sanada, N.; Suzuki, Y.; Fukuda, Y.; Nagoshi, M.

    1993-01-01

    The procedure of quantitative XPS analysis involving the relative sensitivity factors is most convenient to apply to high T c superconductor surfaces because this procedure does not require standards. However, a considerable limitation of such an approach is its relatively low accuracy. In the present work, a proposition is made to use for this purpose a modification of the relative sensitivity factor approach accounting for the matrix and the instrumental effects. The accuracy of this modification when applied to the binary metal alloys is 2% or better. A quantitative XPS analysis was made for surfaces of the compounds Bi 2 Sr 2 CuO 6 , Bi 2 Sr 2 CaCu 2 O 8 , and YBa 2 Cu 3 O Y . The surface composition determined for the polycrystalline samples corresponds reasonably well to the bulk stoichiometry. Slight deficiency of oxygen was found for the Bi-based compounds. The surface exposed on cleavage of the Bi 2 Sr 2 CaCu 2 O 8 single crystal was found to be enriched with bismuth, which indicates that the cleavage occurs along the BiO planes. This result is in agreement with the STM studies published in the literature

  10. Multimodal Nonlinear Optical Imaging for Sensitive Detection of Multiple Pharmaceutical Solid-State Forms and Surface Transformations.

    Science.gov (United States)

    Novakovic, Dunja; Saarinen, Jukka; Rojalin, Tatu; Antikainen, Osmo; Fraser-Miller, Sara J; Laaksonen, Timo; Peltonen, Leena; Isomäki, Antti; Strachan, Clare J

    2017-11-07

    Two nonlinear imaging modalities, coherent anti-Stokes Raman scattering (CARS) and sum-frequency generation (SFG), were successfully combined for sensitive multimodal imaging of multiple solid-state forms and their changes on drug tablet surfaces. Two imaging approaches were used and compared: (i) hyperspectral CARS combined with principal component analysis (PCA) and SFG imaging and (ii) simultaneous narrowband CARS and SFG imaging. Three different solid-state forms of indomethacin-the crystalline gamma and alpha forms, as well as the amorphous form-were clearly distinguished using both approaches. Simultaneous narrowband CARS and SFG imaging was faster, but hyperspectral CARS and SFG imaging has the potential to be applied to a wider variety of more complex samples. These methodologies were further used to follow crystallization of indomethacin on tablet surfaces under two storage conditions: 30 °C/23% RH and 30 °C/75% RH. Imaging with (sub)micron resolution showed that the approach allowed detection of very early stage surface crystallization. The surfaces progressively crystallized to predominantly (but not exclusively) the gamma form at lower humidity and the alpha form at higher humidity. Overall, this study suggests that multimodal nonlinear imaging is a highly sensitive, solid-state (and chemically) specific, rapid, and versatile imaging technique for understanding and hence controlling (surface) solid-state forms and their complex changes in pharmaceuticals.

  11. Cones fabricated by 3D nanoimprint lithography for highly sensitive surface enhanced Raman spectroscopy

    International Nuclear Information System (INIS)

    Wu Wei; Hu Min; Ou Fungsuong; Li Zhiyong; Williams, R Stanley

    2010-01-01

    We demonstrated a cost-effective and deterministic method of patterning 3D cone arrays over a large area by using nanoimprint lithography (NIL). Cones with tip radius of less than 10 nm were successfully duplicated onto the UV-curable imprint resist materials from the silicon cone templates. Such cone structures were shown to be a versatile platform for developing reliable, highly sensitive surface enhanced Raman spectroscopy (SERS) substrates. In contrast to the silicon nanocones, the SERS substrates based on the Au coated cones made by the NIL offered significant improvement of the SERS signal. A further improvement of the SERS signal was observed when the polymer cones were imprinted onto a reflective metallic mirror surface. A sub-zeptomole detection sensitivity for a model molecule, trans-1,2-bis(4-pyridyl)-ethylene (BPE), on the Au coated NIL cone surfaces was achieved.

  12. Seismic analysis of steam generator and parameter sensitivity studies

    International Nuclear Information System (INIS)

    Qian Hao; Xu Dinggen; Yang Ren'an; Liang Xingyun

    2013-01-01

    Background: The steam generator (SG) serves as the primary means for removing the heat generated within the reactor core and is part of the reactor coolant system (RCS) pressure boundary. Purpose: Seismic analysis in required for SG, whose seismic category is Cat. I. Methods: The analysis model of SG is created with moisture separator assembly and tube bundle assembly herein. The seismic analysis is performed with RCS pipe and Reactor Pressure Vessel (RPV). Results: The seismic stress results of SG are obtained. In addition, parameter sensitivities of seismic analysis results are studied, such as the effect of another SG, support, anti-vibration bars (AVBs), and so on. Our results show that seismic results are sensitive to support and AVBs setting. Conclusions: The guidance and comments on these parameters are summarized for equipment design and analysis, which should be focused on in future new type NPP SG's research and design. (authors)

  13. Applications of ion scattering in surface analysis

    International Nuclear Information System (INIS)

    Armour, D.G.

    1981-01-01

    The study of ion scattering from surfaces has made an increasingly important contribution both to the development of highly surface specific analysis techniques and to the understanding of the atomic collision processes associated with ion bombardment of solid surfaces. From an analysis point of view, by appropriate choice of parameters such as ion energy and species, scattering geometry and target temperature, it is possible to study not only the composition of the surface layer but also the detailed atomic arrangement. The ion scattering technique is thus particularly useful for the study of surface compositional and structural changes caused by adsorption, thermal annealing or ion bombardment treatments of simple or composite materials. Ion bombardment induced desorption, damage or atomic mixing can also be effectively studied using scattering techniques. By reviewing the application of the technique to a variety of these technologically important surface investigations, it is possible to illustrate the way in which ion scattering has developed as the understanding of the underlying physics has improved. (author)

  14. Automated differentiation of computer models for sensitivity analysis

    International Nuclear Information System (INIS)

    Worley, B.A.

    1990-01-01

    Sensitivity analysis of reactor physics computer models is an established discipline after more than twenty years of active development of generalized perturbations theory based on direct and adjoint methods. Many reactor physics models have been enhanced to solve for sensitivities of model results to model data. The calculated sensitivities are usually normalized first derivatives although some codes are capable of solving for higher-order sensitivities. The purpose of this paper is to report on the development and application of the GRESS system for automating the implementation of the direct and adjoint techniques into existing FORTRAN computer codes. The GRESS system was developed at ORNL to eliminate the costly man-power intensive effort required to implement the direct and adjoint techniques into already-existing FORTRAN codes. GRESS has been successfully tested for a number of codes over a wide range of applications and presently operates on VAX machines under both VMS and UNIX operating systems

  15. Automated differentiation of computer models for sensitivity analysis

    International Nuclear Information System (INIS)

    Worley, B.A.

    1991-01-01

    Sensitivity analysis of reactor physics computer models is an established discipline after more than twenty years of active development of generalized perturbations theory based on direct and adjoint methods. Many reactor physics models have been enhanced to solve for sensitivities of model results to model data. The calculated sensitivities are usually normalized first derivatives, although some codes are capable of solving for higher-order sensitivities. The purpose of this paper is to report on the development and application of the GRESS system for automating the implementation of the direct and adjoint techniques into existing FORTRAN computer codes. The GRESS system was developed at ORNL to eliminate the costly man-power intensive effort required to implement the direct and adjoint techniques into already-existing FORTRAN codes. GRESS has been successfully tested for a number of codes over a wide range of applications and presently operates on VAX machines under both VMS and UNIX operating systems. (author). 9 refs, 1 tab

  16. A Global Sensitivity Analysis Methodology for Multi-physics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tong, C H; Graziani, F R

    2007-02-02

    Experiments are conducted to draw inferences about an entire ensemble based on a selected number of observations. This applies to both physical experiments as well as computer experiments, the latter of which are performed by running the simulation models at different input configurations and analyzing the output responses. Computer experiments are instrumental in enabling model analyses such as uncertainty quantification and sensitivity analysis. This report focuses on a global sensitivity analysis methodology that relies on a divide-and-conquer strategy and uses intelligent computer experiments. The objective is to assess qualitatively and/or quantitatively how the variabilities of simulation output responses can be accounted for by input variabilities. We address global sensitivity analysis in three aspects: methodology, sampling/analysis strategies, and an implementation framework. The methodology consists of three major steps: (1) construct credible input ranges; (2) perform a parameter screening study; and (3) perform a quantitative sensitivity analysis on a reduced set of parameters. Once identified, research effort should be directed to the most sensitive parameters to reduce their uncertainty bounds. This process is repeated with tightened uncertainty bounds for the sensitive parameters until the output uncertainties become acceptable. To accommodate the needs of multi-physics application, this methodology should be recursively applied to individual physics modules. The methodology is also distinguished by an efficient technique for computing parameter interactions. Details for each step will be given using simple examples. Numerical results on large scale multi-physics applications will be available in another report. Computational techniques targeted for this methodology have been implemented in a software package called PSUADE.

  17. Surface and interface analysis of photovoltaic devices

    International Nuclear Information System (INIS)

    Kazmerski, L.L.

    1983-01-01

    Interface chemistry can control the performance and operational lifetime of solar cells, especially thin-film, polycrystalline devices. The composition and elemental integrity of device surfaces, internal junctions, layer and defect interfces can be related to and dominate the electroptical characteristics of the materials/ devices. This paper examines the compositional properties of external and internal surfaces in polycrystaline solar cells, utilizing high-resolution, complementary surface analysis techniques. The electronic properties of these same regions are evaluated using microelectrical characterization methods. Cell performance, in turn, is explained in terms of these relation-ships. Specifically, two solar cell types are used as examples: (1) the polycrystalline Si homojunction and (2) the (Cd Zn)S/CuInSe 2 heterojunction. Throughout these investigations of photovoltaic devices, the limitations and strengths of the surface and electrical microanalyses techniques are emphasized and discussed. (Author) [pt

  18. Enhanced Sensitivity of Surface Acoustic Wave-Based Rate Sensors Incorporating Metallic Dot Arrays

    Directory of Open Access Journals (Sweden)

    Wen Wang

    2014-02-01

    Full Text Available A new surface acoustic wave (SAW-based rate sensor pattern incorporating metallic dot arrays was developed in this paper. Two parallel SAW delay lines with a reverse direction and an operation frequency of 80 MHz on a same X-112°Y LiTaO3 wafer are fabricated as the feedback of two SAW oscillators, and mixed oscillation frequency was used to characterize the external rotation. To enhance the Coriolis force effect acting on the SAW propagation, a copper (Cu dot array was deposited along the SAW propagation path of the SAW devices. The approach of partial-wave analysis in layered media was referred to analyze the response mechanisms of the SAW based rate sensor, resulting in determination of the optimal design parameters. To improve the frequency stability of the oscillator, the single phase unidirectional transducers (SPUDTs and combed transducer were used to form the SAW device to minimize the insertion loss and accomplish the single mode selection, respectively. Excellent long-term (measured in hours frequency stability of 0.1 ppm/h was obtained. Using the rate table with high precision, the performance of the developed SAW rate sensor was evaluated experimentally; satisfactory detection sensitivity (16.7 Hz∙deg∙s−1 and good linearity were observed.

  19. Sensitivity-Based Modeling of Evaluating Surface Runoff and Sediment Load using Digital and Analog Mechanisms

    Directory of Open Access Journals (Sweden)

    Olotu Yahaya

    2014-07-01

    Full Text Available Analyses of runoff- sediment measurement and evaluation using automated and convectional runoff-meters was carried out at Meteorological and Hydrological Station of Auchi Polytechnic, Auchi using two runoff plots (ABCDa and EFGHm of area 2m 2 each, depth 0.26 m and driven into the soil to the depth of 0.13m. Runoff depths and intensities were measured from each of the positioned runoff plot. Automated runoff-meter has a measuring accuracy of ±0.001l/±0.025 mm and rainfall depth-intensity was measured using tipping-bucket rainguage during the period of 14-month of experimentation. Minimum and maximum rainfall depths of 1.2 and 190.3 mm correspond to measured runoff depths (MRo of 0.0 mm for both measurement approaches and 60.4 mm and 48.9 mm respectively. Automated runoffmeter provides precise, accurate and instantaneous result over the convectional measurement of surface runoff. Runoff measuring accuracy for automated runoff-meter from the plot (ABCDa produces R 2 = 0.99; while R 2 = 0.96 for manual evaluation in plot (EFGHm. WEPP and SWAT models were used to simulate the obtained hydrological variables from the applied measurement mechanisms. The outputs of sensitivity simulation analysis indicate that data from automated measuring systems gives a better modelling index and such could be used for running robust runoff-sediment predictive modelling technique under different reservoir sedimentation and water management scenarios.

  20. Level crossing analysis of growing surfaces

    International Nuclear Information System (INIS)

    Shahbazi, F; Sobhanian, S; Tabar, M Reza Rahimi; Khorram, S; Frootan, G R; Zahed, H

    2003-01-01

    We investigate the average frequency of positive slope ν + α , crossing the height α = h - h-bar in the surface growing processes. The exact level crossing analysis of the random deposition model and the Kardar-Parisi-Zhang equation in the strong coupling limit before creation of singularities is given

  1. Rapid and sensitive detection of synthetic cannabinoids AMB-FUBINACA and α-PVP using surface enhanced Raman scattering (SERS)

    Science.gov (United States)

    Islam, Syed K.; Cheng, Yin Pak; Birke, Ronald L.; Green, Omar; Kubic, Thomas; Lombardi, John R.

    2018-04-01

    The application of surface enhanced Raman scattering (SERS) has been reported as a fast and sensitive analytical method in the trace detection of the two most commonly known synthetic cannabinoids AMB-FUBINACA and alpha-pyrrolidinovalerophenone (α-PVP). FUBINACA and α-PVP are two of the most dangerous synthetic cannabinoids which have been reported to cause numerous deaths in the United States. While instruments such as GC-MS, LC-MS have been traditionally recognized as analytical tools for the detection of these synthetic drugs, SERS has been recently gaining ground in the analysis of these synthetic drugs due to its sensitivity in trace analysis and its effectiveness as a rapid method of detection. This present study shows the limit of detection of a concentration as low as picomolar for AMB-FUBINACA while for α-PVP, the limit of detection is in nanomolar concentration using SERS.

  2. Automated sensitivity analysis: New tools for modeling complex dynamic systems

    International Nuclear Information System (INIS)

    Pin, F.G.

    1987-01-01

    Sensitivity analysis is an established methodology used by researchers in almost every field to gain essential insight in design and modeling studies and in performance assessments of complex systems. Conventional sensitivity analysis methodologies, however, have not enjoyed the widespread use they deserve considering the wealth of information they can provide, partly because of their prohibitive cost or the large initial analytical investment they require. Automated systems have recently been developed at ORNL to eliminate these drawbacks. Compilers such as GRESS and EXAP now allow automatic and cost effective calculation of sensitivities in FORTRAN computer codes. In this paper, these and other related tools are described and their impact and applicability in the general areas of modeling, performance assessment and decision making for radioactive waste isolation problems are discussed

  3. The Volatility of Data Space: Topology Oriented Sensitivity Analysis

    Science.gov (United States)

    Du, Jing; Ligmann-Zielinska, Arika

    2015-01-01

    Despite the difference among specific methods, existing Sensitivity Analysis (SA) technologies are all value-based, that is, the uncertainties in the model input and output are quantified as changes of values. This paradigm provides only limited insight into the nature of models and the modeled systems. In addition to the value of data, a potentially richer information about the model lies in the topological difference between pre-model data space and post-model data space. This paper introduces an innovative SA method called Topology Oriented Sensitivity Analysis, which defines sensitivity as the volatility of data space. It extends SA into a deeper level that lies in the topology of data. PMID:26368929

  4. Interactive Building Design Space Exploration Using Regionalized Sensitivity Analysis

    DEFF Research Database (Denmark)

    Østergård, Torben; Jensen, Rasmus Lund; Maagaard, Steffen

    2017-01-01

    simulation inputs are most important and which have negligible influence on the model output. Popular sensitivity methods include the Morris method, variance-based methods (e.g. Sobol’s), and regression methods (e.g. SRC). However, all these methods only address one output at a time, which makes it difficult...... in combination with the interactive parallel coordinate plot (PCP). The latter is an effective tool to explore stochastic simulations and to find high-performing building designs. The proposed methods help decision makers to focus their attention to the most important design parameters when exploring......Monte Carlo simulations combined with regionalized sensitivity analysis provide the means to explore a vast, multivariate design space in building design. Typically, sensitivity analysis shows how the variability of model output relates to the uncertainties in models inputs. This reveals which...

  5. Sensitization trajectories in childhood revealed by using a cluster analysis

    DEFF Research Database (Denmark)

    Schoos, Ann-Marie M.; Chawes, Bo L.; Melen, Erik

    2017-01-01

    Prospective Studies on Asthma in Childhood 2000 (COPSAC2000) birth cohort with specific IgE against 13 common food and inhalant allergens at the ages of ½, 1½, 4, and 6 years. An unsupervised cluster analysis for 3-dimensional data (nonnegative sparse parallel factor analysis) was used to extract latent......BACKGROUND: Assessment of sensitization at a single time point during childhood provides limited clinical information. We hypothesized that sensitization develops as specific patterns with respect to age at debut, development over time, and involved allergens and that such patterns might be more...... biologically and clinically relevant. OBJECTIVE: We sought to explore latent patterns of sensitization during the first 6 years of life and investigate whether such patterns associate with the development of asthma, rhinitis, and eczema. METHODS: We investigated 398 children from the at-risk Copenhagen...

  6. A study of charge transfer kinetics in dye-sensitized surface conductivity solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Dennis

    2011-05-15

    The efficiency of the quasi-solid-state dye-sensitized solar cell developed by Junghaenel and Tributsch, the so-called Nano Surface Conductivity Solar Cell (NSCSC), was improved from 2% to 3.5% introducing a compact TiO{sub 2} underlayer, modifying the surface of the mesoporous TiO{sub 2} electrode, optimizing the deposition process of the electrolyte film, and replacing the platinum counter electrode by a carbon layer. Space-resolved photocurrent images revealed the importance of a homogeneous distribution of the electrolyte film. An uneven dispersion led to localized areas of high and low photocurrents, whereas the latter were attributed to an insufficient concentration of the redox couple. Impedance spectroscopy was performed on cells containing different concentrations of the redox couple. By modeling the spectra using an equivalent circuit with a transmission line of resistive and capacitive elements, the characteristic parameters of electron transport in the TiO{sub 2}, such as diffusion length and electron lifetime were obtained. The measurements indicated that the transport of the positive charge to the counter electrode is the main process limiting the efficiency of the cells. Excess charge carrier decay in functioning devices was analyzed by contactless transient photoconductance measurements in the microwave frequency range (TRMC). The lifetime of the photogenerated charge carriers was observed to decrease with increasing applied potential, reaching its maximum close to the opencircuit potential of the cell, where the photocurrent density was minimal, i.e. the potential dependent decay observed was limited by the injection of electrons into the front contact. The functioning of this NSCSC indicated that the transport of the positive charge occurs by solid-state diffusion at the surface of the TiO{sub 2} particles. TRMC measurements on subset devices in the form of sensitized TiO{sub 2} layers revealed charge carrier kinetics strongly dependent on the

  7. Comparison of the sensitivity of surface downward longwave radiation to changes in water vapor at two high elevation sites

    International Nuclear Information System (INIS)

    Chen, Yonghua; Naud, Catherine M; Rangwala, Imtiaz; Landry, Christopher C; Miller, James R

    2014-01-01

    Among the potential reasons for enhanced warming rates in many high elevation regions is the nonlinear relationship between surface downward longwave radiation (DLR) and specific humidity (q). In this study we use ground-based observations at two neighboring high elevation sites in Southwestern Colorado that have different local topography and are 1.3 km apart horizontally and 348 m vertically. We examine the spatial consistency of the sensitivities (partial derivatives) of DLR with respect to changes in q, and the sensitivities are obtained from the Jacobian matrix of a neural network analysis. Although the relationship between DLR and q is the same at both sites, the sensitivities are higher when q is smaller, which occurs more frequently at the higher elevation site. There is a distinct hourly distribution in the sensitivities at both sites especially for high sensitivity cases, although the range is greater at the lower elevation site. The hourly distribution of the sensitivities relates to that of q. Under clear skies during daytime, q is similar between the two sites, however under cloudy skies or at night, it is not. This means that the DLR–q sensitivities are similar at the two sites during daytime but not at night, and care must be exercised when using data from one site to infer the impact of water vapor feedbacks at another site, particularly at night. Our analysis suggests that care should be exercised when using the lapse rate adjustment to infill high frequency data in a complex topographical region, particularly when one of the stations is subject to cold air pooling as found here. (letter)

  8. Comparison of the Sensitivity of Surface Downward Longwave Radiation to Changes in Water Vapor at Two High Elevation Sites

    Science.gov (United States)

    Chen, Yonghua; Naud, Catherine M.; Rangwala, Imtiaz; Landry, Christopher C.; Miller, James R.

    2014-01-01

    Among the potential reasons for enhanced warming rates in many high elevation regions is the nonlinear relationship between surface downward longwave radiation (DLR) and specific humidity (q). In this study we use ground-based observations at two neighboring high elevation sites in Southwestern Colorado that have different local topography and are 1.3 kilometers apart horizontally and 348 meters vertically. We examine the spatial consistency of the sensitivities (partial derivatives) of DLR with respect to changes in q, and the sensitivities are obtained from the Jacobian matrix of a neural network analysis. Although the relationship between DLR and q is the same at both sites, the sensitivities are higher when q is smaller, which occurs more frequently at the higher elevation site. There is a distinct hourly distribution in the sensitivities at both sites especially for high sensitivity cases, although the range is greater at the lower elevation site. The hourly distribution of the sensitivities relates to that of q. Under clear skies during daytime, q is similar between the two sites, however under cloudy skies or at night, it is not. This means that the DLR-q sensitivities are similar at the two sites during daytime but not at night, and care must be exercised when using data from one site to infer the impact of water vapor feedbacks at another site, particularly at night. Our analysis suggests that care should be exercised when using the lapse rate adjustment to infill high frequency data in a complex topographical region, particularly when one of the stations is subject to cold air pooling as found here.

  9. Time-dependent reliability sensitivity analysis of motion mechanisms

    International Nuclear Information System (INIS)

    Wei, Pengfei; Song, Jingwen; Lu, Zhenzhou; Yue, Zhufeng

    2016-01-01

    Reliability sensitivity analysis aims at identifying the source of structure/mechanism failure, and quantifying the effects of each random source or their distribution parameters on failure probability or reliability. In this paper, the time-dependent parametric reliability sensitivity (PRS) analysis as well as the global reliability sensitivity (GRS) analysis is introduced for the motion mechanisms. The PRS indices are defined as the partial derivatives of the time-dependent reliability w.r.t. the distribution parameters of each random input variable, and they quantify the effect of the small change of each distribution parameter on the time-dependent reliability. The GRS indices are defined for quantifying the individual, interaction and total contributions of the uncertainty in each random input variable to the time-dependent reliability. The envelope function method combined with the first order approximation of the motion error function is introduced for efficiently estimating the time-dependent PRS and GRS indices. Both the time-dependent PRS and GRS analysis techniques can be especially useful for reliability-based design. This significance of the proposed methods as well as the effectiveness of the envelope function method for estimating the time-dependent PRS and GRS indices are demonstrated with a four-bar mechanism and a car rack-and-pinion steering linkage. - Highlights: • Time-dependent parametric reliability sensitivity analysis is presented. • Time-dependent global reliability sensitivity analysis is presented for mechanisms. • The proposed method is especially useful for enhancing the kinematic reliability. • An envelope method is introduced for efficiently implementing the proposed methods. • The proposed method is demonstrated by two real planar mechanisms.

  10. Probabilistic sensitivity analysis of system availability using Gaussian processes

    International Nuclear Information System (INIS)

    Daneshkhah, Alireza; Bedford, Tim

    2013-01-01

    The availability of a system under a given failure/repair process is a function of time which can be determined through a set of integral equations and usually calculated numerically. We focus here on the issue of carrying out sensitivity analysis of availability to determine the influence of the input parameters. The main purpose is to study the sensitivity of the system availability with respect to the changes in the main parameters. In the simplest case that the failure repair process is (continuous time/discrete state) Markovian, explicit formulae are well known. Unfortunately, in more general cases availability is often a complicated function of the parameters without closed form solution. Thus, the computation of sensitivity measures would be time-consuming or even infeasible. In this paper, we show how Sobol and other related sensitivity measures can be cheaply computed to measure how changes in the model inputs (failure/repair times) influence the outputs (availability measure). We use a Bayesian framework, called the Bayesian analysis of computer code output (BACCO) which is based on using the Gaussian process as an emulator (i.e., an approximation) of complex models/functions. This approach allows effective sensitivity analysis to be achieved by using far smaller numbers of model runs than other methods. The emulator-based sensitivity measure is used to examine the influence of the failure and repair densities' parameters on the system availability. We discuss how to apply the methods practically in the reliability context, considering in particular the selection of parameters and prior distributions and how we can ensure these may be considered independent—one of the key assumptions of the Sobol approach. The method is illustrated on several examples, and we discuss the further implications of the technique for reliability and maintenance analysis

  11. Sensitivity Analysis of features in tolerancing based on constraint function level sets

    International Nuclear Information System (INIS)

    Ziegler, Philipp; Wartzack, Sandro

    2015-01-01

    Usually, the geometry of the manufactured product inherently varies from the nominal geometry. This may negatively affect the product functions and properties (such as quality and reliability), as well as the assemblability of the single components. In order to avoid this, the geometric variation of these component surfaces and associated geometry elements (like hole axes) are restricted by tolerances. Since tighter tolerances lead to significant higher manufacturing costs, tolerances should be specified carefully. Therefore, the impact of deviating component surfaces on functions, properties and assemblability of the product has to be analyzed. As physical experiments are expensive, methods of statistical tolerance analysis tools are widely used in engineering design. Current tolerance simulation tools lack of an appropriate indicator for the impact of deviating component surfaces. In the adoption of Sensitivity Analysis methods, there are several challenges, which arise from the specific framework in tolerancing. This paper presents an approach to adopt Sensitivity Analysis methods on current tolerance simulations with an interface module, which bases on level sets of constraint functions for parameters of the simulation model. The paper is an extension and generalization of Ziegler and Wartzack [1]. Mathematical properties of the constraint functions (convexity, homogeneity), which are important for the computational costs of the Sensitivity Analysis, are shown. The practical use of the method is illustrated in a case study of a plain bearing. - Highlights: • Alternative definition of Deviation Domains. • Proof of mathematical properties of the Deviation Domains. • Definition of the interface between Deviation Domains and Sensitivity Analysis. • Sensitivity analysis of a gearbox to show the methods practical use

  12. Analytic uncertainty and sensitivity analysis of models with input correlations

    Science.gov (United States)

    Zhu, Yueying; Wang, Qiuping A.; Li, Wei; Cai, Xu

    2018-03-01

    Probabilistic uncertainty analysis is a common means of evaluating mathematical models. In mathematical modeling, the uncertainty in input variables is specified through distribution laws. Its contribution to the uncertainty in model response is usually analyzed by assuming that input variables are independent of each other. However, correlated parameters are often happened in practical applications. In the present paper, an analytic method is built for the uncertainty and sensitivity analysis of models in the presence of input correlations. With the method, it is straightforward to identify the importance of the independence and correlations of input variables in determining the model response. This allows one to decide whether or not the input correlations should be considered in practice. Numerical examples suggest the effectiveness and validation of our analytic method in the analysis of general models. A practical application of the method is also proposed to the uncertainty and sensitivity analysis of a deterministic HIV model.

  13. Addressing Curse of Dimensionality in Sensitivity Analysis: How Can We Handle High-Dimensional Problems?

    Science.gov (United States)

    Safaei, S.; Haghnegahdar, A.; Razavi, S.

    2016-12-01

    Complex environmental models are now the primary tool to inform decision makers for the current or future management of environmental resources under the climate and environmental changes. These complex models often contain a large number of parameters that need to be determined by a computationally intensive calibration procedure. Sensitivity analysis (SA) is a very useful tool that not only allows for understanding the model behavior, but also helps in reducing the number of calibration parameters by identifying unimportant ones. The issue is that most global sensitivity techniques are highly computationally demanding themselves for generating robust and stable sensitivity metrics over the entire model response surface. Recently, a novel global sensitivity analysis method, Variogram Analysis of Response Surfaces (VARS), is introduced that can efficiently provide a comprehensive assessment of global sensitivity using the Variogram concept. In this work, we aim to evaluate the effectiveness of this highly efficient GSA method in saving computational burden, when applied to systems with extra-large number of input factors ( 100). We use a test function and a hydrological modelling case study to demonstrate the capability of VARS method in reducing problem dimensionality by identifying important vs unimportant input factors.

  14. Repository surface design site layout analysis

    International Nuclear Information System (INIS)

    Montalvo, H.R.

    1998-01-01

    The purpose of this analysis is to establish the arrangement of the Yucca Mountain Repository surface facilities and features near the North Portal. The analysis updates and expands the North Portal area site layout concept presented in the ACD, including changes to reflect the resizing of the Waste Handling Building (WHB), Waste Treatment Building (WTB), Carrier Preparation Building (CPB), and site parking areas; the addition of the Carrier Washdown Buildings (CWBs); the elimination of the Cask Maintenance Facility (CMF); and the development of a concept for site grading and flood control. The analysis also establishes the layout of the surface features (e.g., roads and utilities) that connect all the repository surface areas (North Portal Operations Area, South Portal Development Operations Area, Emplacement Shaft Surface Operations Area, and Development Shaft Surface Operations Area) and locates an area for a potential lag storage facility. Details of South Portal and shaft layouts will be covered in separate design analyses. The objective of this analysis is to provide a suitable level of design for the Viability Assessment (VA). The analysis was revised to incorporate additional material developed since the issuance of Revision 01. This material includes safeguards and security input, utility system input (size and location of fire water tanks and pump houses, potable water and sanitary sewage rates, size of wastewater evaporation pond, size and location of the utility building, size of the bulk fuel storage tank, and size and location of other exterior process equipment), main electrical substation information, redundancy of water supply and storage for the fire support system, and additional information on the storm water retention pond

  15. Sensitivity Analysis Applied in Design of Low Energy Office Building

    DEFF Research Database (Denmark)

    Heiselberg, Per; Brohus, Henrik

    2008-01-01

    satisfies the design requirements and objectives. In the design of sustainable Buildings it is beneficial to identify the most important design parameters in order to develop more efficiently alternative design solutions or reach optimized design solutions. A sensitivity analysis makes it possible...

  16. Application of Sensitivity Analysis in Design of Sustainable Buildings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Brohus, Henrik; Hesselholt, Allan Tind

    2007-01-01

    satisfies the design requirements and objectives. In the design of sustainable Buildings it is beneficial to identify the most important design parameters in order to develop more efficiently alternative design solutions or reach optimized design solutions. A sensitivity analysis makes it possible...

  17. Sensitivity analysis of physiochemical interaction model: which pair ...

    African Journals Online (AJOL)

    ... of two model parameters at a time on the solution trajectory of physiochemical interaction over a time interval. Our aim is to use this powerful mathematical technique to select the important pair of parameters of this physical process which is cost-effective. Keywords: Passivation Rate, Sensitivity Analysis, ODE23, ODE45 ...

  18. Bayesian Sensitivity Analysis of Statistical Models with Missing Data.

    Science.gov (United States)

    Zhu, Hongtu; Ibrahim, Joseph G; Tang, Niansheng

    2014-04-01

    Methods for handling missing data depend strongly on the mechanism that generated the missing values, such as missing completely at random (MCAR) or missing at random (MAR), as well as other distributional and modeling assumptions at various stages. It is well known that the resulting estimates and tests may be sensitive to these assumptions as well as to outlying observations. In this paper, we introduce various perturbations to modeling assumptions and individual observations, and then develop a formal sensitivity analysis to assess these perturbations in the Bayesian analysis of statistical models with missing data. We develop a geometric framework, called the Bayesian perturbation manifold, to characterize the intrinsic structure of these perturbations. We propose several intrinsic influence measures to perform sensitivity analysis and quantify the effect of various perturbations to statistical models. We use the proposed sensitivity analysis procedure to systematically investigate the tenability of the non-ignorable missing at random (NMAR) assumption. Simulation studies are conducted to evaluate our methods, and a dataset is analyzed to illustrate the use of our diagnostic measures.

  19. Sensitivity analysis for contagion effects in social networks

    Science.gov (United States)

    VanderWeele, Tyler J.

    2014-01-01

    Analyses of social network data have suggested that obesity, smoking, happiness and loneliness all travel through social networks. Individuals exert “contagion effects” on one another through social ties and association. These analyses have come under critique because of the possibility that homophily from unmeasured factors may explain these statistical associations and because similar findings can be obtained when the same methodology is applied to height, acne and head-aches, for which the conclusion of contagion effects seems somewhat less plausible. We use sensitivity analysis techniques to assess the extent to which supposed contagion effects for obesity, smoking, happiness and loneliness might be explained away by homophily or confounding and the extent to which the critique using analysis of data on height, acne and head-aches is relevant. Sensitivity analyses suggest that contagion effects for obesity and smoking cessation are reasonably robust to possible latent homophily or environmental confounding; those for happiness and loneliness are somewhat less so. Supposed effects for height, acne and head-aches are all easily explained away by latent homophily and confounding. The methodology that has been employed in past studies for contagion effects in social networks, when used in conjunction with sensitivity analysis, may prove useful in establishing social influence for various behaviors and states. The sensitivity analysis approach can be used to address the critique of latent homophily as a possible explanation of associations interpreted as contagion effects. PMID:25580037

  20. Sensitivity Analysis of a Horizontal Earth Electrode under Impulse ...

    African Journals Online (AJOL)

    This paper presents the sensitivity analysis of an earthing conductor under the influence of impulse current arising from a lightning stroke. The approach is based on the 2nd order finite difference time domain (FDTD). The earthing conductor is regarded as a lossy transmission line where it is divided into series connected ...

  1. Beyond the GUM: variance-based sensitivity analysis in metrology

    International Nuclear Information System (INIS)

    Lira, I

    2016-01-01

    Variance-based sensitivity analysis is a well established tool for evaluating the contribution of the uncertainties in the inputs to the uncertainty in the output of a general mathematical model. While the literature on this subject is quite extensive, it has not found widespread use in metrological applications. In this article we present a succinct review of the fundamentals of sensitivity analysis, in a form that should be useful to most people familiarized with the Guide to the Expression of Uncertainty in Measurement (GUM). Through two examples, it is shown that in linear measurement models, no new knowledge is gained by using sensitivity analysis that is not already available after the terms in the so-called ‘law of propagation of uncertainties’ have been computed. However, if the model behaves non-linearly in the neighbourhood of the best estimates of the input quantities—and if these quantities are assumed to be statistically independent—sensitivity analysis is definitely advantageous for gaining insight into how they can be ranked according to their importance in establishing the uncertainty of the measurand. (paper)

  2. Sensitivity analysis of the Ohio phosphorus risk index

    Science.gov (United States)

    The Phosphorus (P) Index is a widely used tool for assessing the vulnerability of agricultural fields to P loss; yet, few of the P Indices developed in the U.S. have been evaluated for their accuracy. Sensitivity analysis is one approach that can be used prior to calibration and field-scale testing ...

  3. Sensitivity analysis for oblique incidence reflectometry using Monte Carlo simulations

    DEFF Research Database (Denmark)

    Kamran, Faisal; Andersen, Peter E.

    2015-01-01

    profiles. This article presents a sensitivity analysis of the technique in turbid media. Monte Carlo simulations are used to investigate the technique and its potential to distinguish the small changes between different levels of scattering. We present various regions of the dynamic range of optical...

  4. Omitted Variable Sensitivity Analysis with the Annotated Love Plot

    Science.gov (United States)

    Hansen, Ben B.; Fredrickson, Mark M.

    2014-01-01

    The goal of this research is to make sensitivity analysis accessible not only to empirical researchers but also to the various stakeholders for whom educational evaluations are conducted. To do this it derives anchors for the omitted variable (OV)-program participation association intrinsically, using the Love plot to present a wide range of…

  5. Weighting-Based Sensitivity Analysis in Causal Mediation Studies

    Science.gov (United States)

    Hong, Guanglei; Qin, Xu; Yang, Fan

    2018-01-01

    Through a sensitivity analysis, the analyst attempts to determine whether a conclusion of causal inference could be easily reversed by a plausible violation of an identification assumption. Analytic conclusions that are harder to alter by such a violation are expected to add a higher value to scientific knowledge about causality. This article…

  6. Sensitivity analysis of railpad parameters on vertical railway track dynamics

    NARCIS (Netherlands)

    Oregui Echeverria-Berreyarza, M.; Nunez Vicencio, Alfredo; Dollevoet, R.P.B.J.; Li, Z.

    2016-01-01

    This paper presents a sensitivity analysis of railpad parameters on vertical railway track dynamics, incorporating the nonlinear behavior of the fastening (i.e., downward forces compress the railpad whereas upward forces are resisted by the clamps). For this purpose, solid railpads, rail-railpad

  7. Methods for global sensitivity analysis in life cycle assessment

    NARCIS (Netherlands)

    Groen, Evelyne A.; Bokkers, Eddy; Heijungs, Reinout; Boer, de Imke J.M.

    2017-01-01

    Purpose: Input parameters required to quantify environmental impact in life cycle assessment (LCA) can be uncertain due to e.g. temporal variability or unknowns about the true value of emission factors. Uncertainty of environmental impact can be analysed by means of a global sensitivity analysis to

  8. Sensitivity analysis on ultimate strength of aluminium stiffened panels

    DEFF Research Database (Denmark)

    Rigo, P.; Sarghiuta, R.; Estefen, S.

    2003-01-01

    This paper presents the results of an extensive sensitivity analysis carried out by the Committee III.1 "Ultimate Strength" of ISSC?2003 in the framework of a benchmark on the ultimate strength of aluminium stiffened panels. Previously, different benchmarks were presented by ISSC committees on ul...

  9. Sensitivity and specificity of coherence and phase synchronization analysis

    International Nuclear Information System (INIS)

    Winterhalder, Matthias; Schelter, Bjoern; Kurths, Juergen; Schulze-Bonhage, Andreas; Timmer, Jens

    2006-01-01

    In this Letter, we show that coherence and phase synchronization analysis are sensitive but not specific in detecting the correct class of underlying dynamics. We propose procedures to increase specificity and demonstrate the power of the approach by application to paradigmatic dynamic model systems

  10. Sensitivity Analysis of Structures by Virtual Distortion Method

    DEFF Research Database (Denmark)

    Gierlinski, J.T.; Holnicki-Szulc, J.; Sørensen, John Dalsgaard

    1991-01-01

    are used in structural optimization, see Haftka [4]. The recently developed Virtual Distortion Method (VDM) is a numerical technique which offers an efficient approach to calculation of the sensitivity derivatives. This method has been orginally applied to structural remodelling and collapse analysis, see...

  11. Design tradeoff studies and sensitivity analysis. Appendix B

    Energy Technology Data Exchange (ETDEWEB)

    1979-05-25

    The results of the design trade-off studies and the sensitivity analysis of Phase I of the Near Term Hybrid Vehicle (NTHV) Program are presented. The effects of variations in the design of the vehicle body, propulsion systems, and other components on vehicle power, weight, cost, and fuel economy and an optimized hybrid vehicle design are discussed. (LCL)

  12. Sensitive Detection of Biomolecules by Surface Enhanced Raman Scattering using Plant Leaves as Natural Substrates

    Directory of Open Access Journals (Sweden)

    Sharma Vipul

    2017-01-01

    Full Text Available Detection of biomolecules is highly important for biomedical and other biological applications. Although several methods exist for the detection of biomolecules, surface enhanced Raman scattering (SERS has a unique role in greatly enhancing the sensitivity. In this work, we have demonstrated the use of natural plant leaves as facile, low cost and eco-friendly SERS substrates for the sensitive detection of biomolecules. Specifically, we have investigated the influence of surface topography of five different plant leaf based substrates, deposited with Au, on the SERS performance by using L-cysteine as a model biomolecule. In addition, we have also compared the effect of sputter deposition of Au thin film with dropcast deposition of Au nanoparticles on the leaf substrates. Our results indicate that L-cysteine could be detected with high sensitivity using these plant leaf based substrates and the leaf possessing hierarchical micro/nanostructures on its surface shows higher SERS enhancement compared to a leaf having a nearplanar surface. Furthermore, leaves with drop-casted Au nanoparticle clusters performed better than the leaves sputter deposited with a thin Au film.

  13. Enhancing dye-sensitized solar cell efficiency by anode surface treatments

    International Nuclear Information System (INIS)

    Chang, Chao-Hsuan; Lin, Hsin-Han; Chen, Chin-Cheng; Hong, Franklin C.-N.

    2014-01-01

    In this study, titanium substrates treated with HF solution and KOH solution sequentially forming micro- and nano-structures were used for the fabrication of flexible dye-sensitized solar cells (DSSCs). After wet etching treatments, the titanium substrates were then exposed to the O 2 plasma treatment and further immersed in titanium tetrachloride (TiCl 4 ) solution. The process conditions for producing a very thin TiO 2 blocking layer were studied, in order to avoid solar cell current leakage for increasing the solar cell efficiency. Subsequently, TiO 2 nanoparticles were spin-coated on Ti substrates with varied thickness. The dye-sensitized solar cells on the titanium substrates were subjected to simulate AM 1.5 G irradiation of 100 mW/cm 2 using backside illumination mode. Surface treatments of Ti substrate and TiO 2 anode were found to play a significant role in improving the efficiency of DSSC. The efficiencies of the backside illumination solar cells were raised from 4.6% to 7.8% by integrating these surface treatments. - Highlights: • The flexible dye-sensitized solar cell (DSSC) device can be fabricated. • Many effective surface treatment methods to improve DSSC efficiency are elucidated. • The efficiency is dramatically enhanced by integrating surface treatment methods. • The back-illuminated DSSC efficiency was raised from 4.6% to 7.8%

  14. SURFACE TEXTURE ANALYSIS FOR FUNCTIONALITY CONTROL

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Andreasen, Jan Lasson; Tosello, Guido

    This document is used in connection with three exercises of 3 hours duration as a part of the course VISION ONLINE – One week course on Precision & Nanometrology. The exercises concern surface texture analysis for functionality control, in connection with three different case stories. This docume...... contains a short description of each case story, 3-D roughness parameters analysis and relation with the product’s functionality.......This document is used in connection with three exercises of 3 hours duration as a part of the course VISION ONLINE – One week course on Precision & Nanometrology. The exercises concern surface texture analysis for functionality control, in connection with three different case stories. This document...

  15. Sensitivity analysis and power for instrumental variable studies.

    Science.gov (United States)

    Wang, Xuran; Jiang, Yang; Zhang, Nancy R; Small, Dylan S

    2018-03-31

    In observational studies to estimate treatment effects, unmeasured confounding is often a concern. The instrumental variable (IV) method can control for unmeasured confounding when there is a valid IV. To be a valid IV, a variable needs to be independent of unmeasured confounders and only affect the outcome through affecting the treatment. When applying the IV method, there is often concern that a putative IV is invalid to some degree. We present an approach to sensitivity analysis for the IV method which examines the sensitivity of inferences to violations of IV validity. Specifically, we consider sensitivity when the magnitude of association between the putative IV and the unmeasured confounders and the direct effect of the IV on the outcome are limited in magnitude by a sensitivity parameter. Our approach is based on extending the Anderson-Rubin test and is valid regardless of the strength of the instrument. A power formula for this sensitivity analysis is presented. We illustrate its usage via examples about Mendelian randomization studies and its implications via a comparison of using rare versus common genetic variants as instruments. © 2018, The International Biometric Society.

  16. Major and trace elements in mouse bone measured by surface and bulk sensitive methods

    International Nuclear Information System (INIS)

    Benkoe, I.; Geresi, K.; Ungvari, E.; Szabo, B.; Paripas, B.

    2011-01-01

    Complete text of publication follows. In the past years an increasing research interest turned to the accurate determination of the components of bone samples. These investigations focused on both the major and trace elements in the bone. Work in this field is strongly motivated because various major and trace element concentrations can be good indicators of several diseases. Number of studies also focused on the determination of the components both in the organic and inorganic parts of the bone separately, because they both have role during bone remodeling processes. Also important to note that bone can be one of the final destinations in the body where toxic elements are deposited. In this work we performed various surface and bulk sensitive analyses for the mouse bone samples to determine its major and trace element components. We have shown concentration profiles for various major and observable trace elements of the mouse bone. We found, in accordance with our expectation, that the mostly surface sensitive XPS technique is not suitable to determine the concentration of the trace elements in bone samples. It was also shown that XPS is a valuable tool not only in the determination of the chemical states of the major components of the bone powder but in the quantitative determination of their relative concentrations. Both the major and the trace elements of the bone samples are determined using PIXE and SNMS spectra. Although the information depths are very different for PIXE (a few tens of micrometer) and for XPS analysis (a few nanometers), our present PIXE result, using the bone sample in its original form for the concentration ratio between Ca and P is in excellent agreement with the XPS results using calcinated mouse bone powder. Discrepancy in Ca/Mg ratio (PIXE: 35.7 and XPS: 12.7) maybe due to many factors, which influence this ratio in bone samples. In the case of PIXE we studied native bones and determined composition of the compact bone at outside

  17. Bloch surface wave structures for high sensitivity detection and compact waveguiding

    Science.gov (United States)

    Khan, Muhammad Umar; Corbett, Brian

    2016-01-01

    Resonant propagating waves created on the surface of a dielectric multilayer stack, called Bloch surface waves (BSW), can be designed for high sensitivity monitoring of the adjacent refractive index as an alternative platform to the metal-based surface plasmon resonance (SPR) sensing. The resonant wavelength and polarization can be designed by engineering of the dielectric layers unlike the fixed resonance of SPR, while the wide bandwidth low loss of dielectrics permits sharper resonances, longer propagation lengths and thus their use in waveguiding devices. The transparency of the dielectrics allows the excitation and monitoring of surface-bound fluorescent molecules. We review the recent developments in this technology. We show the advantages that can be obtained by using high index contrast layered structures. Operating at 1550 nm wavelengths will allow the BSW sensors to be implemented in the silicon photonics platform where active waveguiding can be used in the realization of compact planar integrated circuits for multi-parameter sensing.

  18. Surface analysis with STM and AFM

    CERN Document Server

    Magonov, Sergi N

    1996-01-01

    Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) are powerful tools for surface examination. In the past, many STM and AFM studies led to erroneous conclusions due to lack of proper theoretical considerations and of an understanding of how image patterns are affected by measurement conditions. For this book, two world experts, one on theoretical analysis and the other on experimental characterization, have joined forces to bring together essential components of STM and AFM studies: The practical aspects of STM, the image simulation by surface electron density plot calculat

  19. Sensitivity analysis of LOFT L2-5 test calculations

    International Nuclear Information System (INIS)

    Prosek, Andrej

    2014-01-01

    The uncertainty quantification of best-estimate code predictions is typically accompanied by a sensitivity analysis, in which the influence of the individual contributors to uncertainty is determined. The objective of this study is to demonstrate the improved fast Fourier transform based method by signal mirroring (FFTBM-SM) for the sensitivity analysis. The sensitivity study was performed for the LOFT L2-5 test, which simulates the large break loss of coolant accident. There were 14 participants in the BEMUSE (Best Estimate Methods-Uncertainty and Sensitivity Evaluation) programme, each performing a reference calculation and 15 sensitivity runs of the LOFT L2-5 test. The important input parameters varied were break area, gap conductivity, fuel conductivity, decay power etc. For the influence of input parameters on the calculated results the FFTBM-SM was used. The only difference between FFTBM-SM and original FFTBM is that in the FFTBM-SM the signals are symmetrized to eliminate the edge effect (the so called edge is the difference between the first and last data point of one period of the signal) in calculating average amplitude. It is very important to eliminate unphysical contribution to the average amplitude, which is used as a figure of merit for input parameter influence on output parameters. The idea is to use reference calculation as 'experimental signal', 'sensitivity run' as 'calculated signal', and average amplitude as figure of merit for sensitivity instead for code accuracy. The larger is the average amplitude the larger is the influence of varied input parameter. The results show that with FFTBM-SM the analyst can get good picture of the contribution of the parameter variation to the results. They show when the input parameters are influential and how big is this influence. FFTBM-SM could be also used to quantify the influence of several parameter variations on the results. However, the influential parameters could not be

  20. A sensitive electrochemiluminescence cytosensor for quantitative evaluation of epidermal growth factor receptor expressed on cell surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yanjuan; Zhang, Shaolian; Wen, Qingqing; Huang, Hongxing; Yang, Peihui, E-mail: typh@jnu.edu.cn

    2015-06-30

    Highlights: • EGF-cytosensor was used for evaluating EGFR expression level on cell surfaces. • CdSQDs and EGF were coated on magnetic beads (MBs) for ECL-probe. • Good sensitivity was achieved due to the signal amplification of ECL-probe. - Abstract: A sensitive electrochemiluminescence (ECL) strategy for evaluating the epidermal growth factor receptor (EGFR) expression level on cell surfaces was designed by integrating the specific recognition of EGFR expressed on MCF-7 cell surfaces with an epidermal growth factor (EGF)-funtionalized CdS quantum dots (CdSQDs)-capped magnetic bead (MB) probe. The high sensitivity of ECL probe of EGF-funtionalized CdSQD-capped-MB was used for competitive recognition with EGFR expressed on cell surfaces with recombinant EGFR protein. The changes of ECL intensity depended on both the cell number and the expression level of EGFR receptor on cell surfaces. A wide linear response to cells ranging from 80 to 4 × 10{sup 6} cells mL{sup −1} with a detection limit of 40 cells mL{sup −1} was obtained. The EGF-cytosensor was used to evaluate EGFR expression levels on MCF-7 cells, and the average number of EGFR receptor on single MCF-7 cells was 1.35 × 10{sup 5} with the relative standard deviation of 4.3%. This strategy was further used for in-situ and real-time evaluating EGFR receptor expressed on cell surfaces in response to drugs stimulation at different concentration and incubation time. The proposed method provided potential applications in the detection of receptors on cancer cells and anticancer drugs screening.

  1. Sensitivity/uncertainty analysis of a borehole scenario comparing Latin Hypercube Sampling and deterministic sensitivity approaches

    International Nuclear Information System (INIS)

    Harper, W.V.; Gupta, S.K.

    1983-10-01

    A computer code was used to study steady-state flow for a hypothetical borehole scenario. The model consists of three coupled equations with only eight parameters and three dependent variables. This study focused on steady-state flow as the performance measure of interest. Two different approaches to sensitivity/uncertainty analysis were used on this code. One approach, based on Latin Hypercube Sampling (LHS), is a statistical sampling method, whereas, the second approach is based on the deterministic evaluation of sensitivities. The LHS technique is easy to apply and should work well for codes with a moderate number of parameters. Of deterministic techniques, the direct method is preferred when there are many performance measures of interest and a moderate number of parameters. The adjoint method is recommended when there are a limited number of performance measures and an unlimited number of parameters. This unlimited number of parameters capability can be extremely useful for finite element or finite difference codes with a large number of grid blocks. The Office of Nuclear Waste Isolation will use the technique most appropriate for an individual situation. For example, the adjoint method may be used to reduce the scope to a size that can be readily handled by a technique such as LHS. Other techniques for sensitivity/uncertainty analysis, e.g., kriging followed by conditional simulation, will be used also. 15 references, 4 figures, 9 tables

  2. Sensitivity and uncertainty analysis of NET/ITER shielding blankets

    International Nuclear Information System (INIS)

    Hogenbirk, A.; Gruppelaar, H.; Verschuur, K.A.

    1990-09-01

    Results are presented of sensitivity and uncertainty calculations based upon the European fusion file (EFF-1). The effect of uncertainties in Fe, Cr and Ni cross sections on the nuclear heating in the coils of a NET/ITER shielding blanket has been studied. The analysis has been performed for the total cross section as well as partial cross sections. The correct expression for the sensitivity profile was used, including the gain term. The resulting uncertainty in the nuclear heating lies between 10 and 20 per cent. (author). 18 refs.; 2 figs.; 2 tabs

  3. Sensitivity analysis of critical experiments with evaluated nuclear data libraries

    International Nuclear Information System (INIS)

    Fujiwara, D.; Kosaka, S.

    2008-01-01

    Criticality benchmark testing was performed with evaluated nuclear data libraries for thermal, low-enriched uranium fuel rod applications. C/E values for k eff were calculated with the continuous-energy Monte Carlo code MVP2 and its libraries generated from Endf/B-VI.8, Endf/B-VII.0, JENDL-3.3 and JEFF-3.1. Subsequently, the observed k eff discrepancies between libraries were decomposed to specify the source of difference in the nuclear data libraries using sensitivity analysis technique. The obtained sensitivity profiles are also utilized to estimate the adequacy of cold critical experiments to the boiling water reactor under hot operating condition. (authors)

  4. pH-sensitive diamond field-effect transistors (FETs) with directly aminated channel surface

    International Nuclear Information System (INIS)

    Song, Kwang-Soup; Nakamura, Yusuke; Sasaki, Yuichi; Degawa, Munenori; Yang, Jung-Hoon; Kawarada, Hiroshi

    2006-01-01

    We have introduced pH sensors fabricated on diamond thin films through modification of the surface-terminated atom. We directly modified the diamond surface from hydrogen to amine or oxygen with ultraviolet (UV) irradiation under ammonia gas. The quantified amine site based on the spectra obtained by X-ray photoelectron spectroscopy (XPS) is 26% (2.6 x 10 14 cm -2 ) with UV irradiation for 8 h and its coverage is dependent on the UV irradiation time. This directly aminated diamond surface is stable with long-term exposure in air and electrolyte solution. We fabricated diamond solution-gate field-effect transistors (SGFETs) without insulating layers on the channel surface. These diamond SGFETs with amine modified by direct amination are sensitive to pH (45 mV/pH) over a wide range from pH 2 to 12 and their sensitivity is dependent on the density of binding sites corresponding to UV irradiation time on the channel surface

  5. Importance measures in global sensitivity analysis of nonlinear models

    International Nuclear Information System (INIS)

    Homma, Toshimitsu; Saltelli, Andrea

    1996-01-01

    The present paper deals with a new method of global sensitivity analysis of nonlinear models. This is based on a measure of importance to calculate the fractional contribution of the input parameters to the variance of the model prediction. Measures of importance in sensitivity analysis have been suggested by several authors, whose work is reviewed in this article. More emphasis is given to the developments of sensitivity indices by the Russian mathematician I.M. Sobol'. Given that Sobol' treatment of the measure of importance is the most general, his formalism is employed throughout this paper where conceptual and computational improvements of the method are presented. The computational novelty of this study is the introduction of the 'total effect' parameter index. This index provides a measure of the total effect of a given parameter, including all the possible synergetic terms between that parameter and all the others. Rank transformation of the data is also introduced in order to increase the reproducibility of the method. These methods are tested on a few analytical and computer models. The main conclusion of this work is the identification of a sensitivity analysis methodology which is both flexible, accurate and informative, and which can be achieved at reasonable computational cost

  6. Rethinking Sensitivity Analysis of Nuclear Simulations with Topology

    Energy Technology Data Exchange (ETDEWEB)

    Dan Maljovec; Bei Wang; Paul Rosen; Andrea Alfonsi; Giovanni Pastore; Cristian Rabiti; Valerio Pascucci

    2016-01-01

    In nuclear engineering, understanding the safety margins of the nuclear reactor via simulations is arguably of paramount importance in predicting and preventing nuclear accidents. It is therefore crucial to perform sensitivity analysis to understand how changes in the model inputs affect the outputs. Modern nuclear simulation tools rely on numerical representations of the sensitivity information -- inherently lacking in visual encodings -- offering limited effectiveness in communicating and exploring the generated data. In this paper, we design a framework for sensitivity analysis and visualization of multidimensional nuclear simulation data using partition-based, topology-inspired regression models and report on its efficacy. We rely on the established Morse-Smale regression technique, which allows us to partition the domain into monotonic regions where easily interpretable linear models can be used to assess the influence of inputs on the output variability. The underlying computation is augmented with an intuitive and interactive visual design to effectively communicate sensitivity information to the nuclear scientists. Our framework is being deployed into the multi-purpose probabilistic risk assessment and uncertainty quantification framework RAVEN (Reactor Analysis and Virtual Control Environment). We evaluate our framework using an simulation dataset studying nuclear fuel performance.

  7. Dye-Sensitized Solar Cells Based on High Surface Area Nanocrystalline Zinc Oxide Spheres

    Directory of Open Access Journals (Sweden)

    Pavuluri Srinivasu

    2011-01-01

    Full Text Available High surface area nanocrystalline zinc oxide material is fabricated using mesoporous nanostructured carbon as a sacrificial template through combustion process. The resulting material is characterized by XRD, N2 adsorption, HR-SEM, and HR-TEM. The nitrogen adsorption measurement indicates that the materials possess BET specific surface area ca. 30 m2/g. Electron microscopy images prove that the zinc oxide spheres possess particle size in the range of 0.12 μm–0.17 μm. The nanocrystalline zinc oxide spheres show 1.0% of energy conversion efficiency for dye-sensitized solar cells.

  8. Surface Grafting of Ru(II) Diazonium-Based Sensitizers on Metal Oxides Enhances Alkaline Stability for Solar Energy Conversion.

    Science.gov (United States)

    Bangle, Rachel; Sampaio, Renato N; Troian-Gautier, Ludovic; Meyer, Gerald J

    2018-01-24

    The electrografting of [Ru(ttt)(tpy-C 6 H 4 -N 2 + )] 3+ , where "ttt" is 4,4',4″-tri-tert-butyl-2,2':6',2″-terpyridine, was investigated on several wide band gap metal oxide surfaces (TiO 2 , SnO 2 , ZrO 2 , ZnO, In 2 O 3 :Sn) and compared to structurally analogous sensitizers that differed only by the anchoring group, i.e., -PO 3 H 2 and -COOH. An optimized procedure for diazonium electrografting to semiconductor metal oxides is presented that allowed surface coverages that ranged between 4.7 × 10 -8 and 10.6 × 10 -8 mol cm -2 depending on the nature of the metal oxide. FTIR analysis showed the disappearance of the diazonium stretch at 2266 cm -1 after electrografting. XPS analysis revealed a characteristic peak of Ru 3d at 285 eV as well as a peak at 531.6 eV that was attributed to O 1s in Ti-O-C bonds. Photocurrents were measured to assess electron injection efficiency of these modified surfaces. The electrografted sensitizers exhibited excellent stability across a range of pHs spanning from 1 to 14, where classical binding groups such as carboxylic and phosphonic derivatives were hydrolyzed.

  9. Uncertainty quantification and sensitivity analysis with CASL Core Simulator VERA-CS

    International Nuclear Information System (INIS)

    Brown, C.S.; Zhang, Hongbin

    2016-01-01

    VERA-CS (Virtual Environment for Reactor Applications, Core Simulator) is a coupled neutron transport and thermal-hydraulics code under development by the Consortium for Advanced Simulation of Light Water Reactors (CASL). An approach to uncertainty quantification and sensitivity analysis with VERA-CS was developed and a new toolkit was created to perform uncertainty quantification and sensitivity analysis. A 2 × 2 fuel assembly model was developed and simulated by VERA-CS, and uncertainty quantification and sensitivity analysis were performed with fourteen uncertain input parameters. The minimum departure from nucleate boiling ratio (MDNBR), maximum fuel center-line temperature, and maximum outer clad surface temperature were chosen as the selected figures of merit. Pearson, Spearman, and partial correlation coefficients were considered for all of the figures of merit in sensitivity analysis and coolant inlet temperature was consistently the most influential parameter. Parameters used as inputs to the critical heat flux calculation with the W-3 correlation were shown to be the most influential on the MDNBR, maximum fuel center-line temperature, and maximum outer clad surface temperature.

  10. Prior Sensitivity Analysis in Default Bayesian Structural Equation Modeling.

    Science.gov (United States)

    van Erp, Sara; Mulder, Joris; Oberski, Daniel L

    2017-11-27

    Bayesian structural equation modeling (BSEM) has recently gained popularity because it enables researchers to fit complex models and solve some of the issues often encountered in classical maximum likelihood estimation, such as nonconvergence and inadmissible solutions. An important component of any Bayesian analysis is the prior distribution of the unknown model parameters. Often, researchers rely on default priors, which are constructed in an automatic fashion without requiring substantive prior information. However, the prior can have a serious influence on the estimation of the model parameters, which affects the mean squared error, bias, coverage rates, and quantiles of the estimates. In this article, we investigate the performance of three different default priors: noninformative improper priors, vague proper priors, and empirical Bayes priors-with the latter being novel in the BSEM literature. Based on a simulation study, we find that these three default BSEM methods may perform very differently, especially with small samples. A careful prior sensitivity analysis is therefore needed when performing a default BSEM analysis. For this purpose, we provide a practical step-by-step guide for practitioners to conducting a prior sensitivity analysis in default BSEM. Our recommendations are illustrated using a well-known case study from the structural equation modeling literature, and all code for conducting the prior sensitivity analysis is available in the online supplemental materials. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  11. Analysis of Sea Ice Cover Sensitivity in Global Climate Model

    Directory of Open Access Journals (Sweden)

    V. P. Parhomenko

    2014-01-01

    Full Text Available The paper presents joint calculations using a 3D atmospheric general circulation model, an ocean model, and a sea ice evolution model. The purpose of the work is to analyze a seasonal and annual evolution of sea ice, long-term variability of a model ice cover, and its sensitivity to some parameters of model as well to define atmosphere-ice-ocean interaction.Results of 100 years simulations of Arctic basin sea ice evolution are analyzed. There are significant (about 0.5 m inter-annual fluctuations of an ice cover.The ice - atmosphere sensible heat flux reduced by 10% leads to the growth of average sea ice thickness within the limits of 0.05 m – 0.1 m. However in separate spatial points the thickness decreases up to 0.5 m. An analysis of the seasonably changing average ice thickness with decreasing, as compared to the basic variant by 0.05 of clear sea ice albedo and that of snow shows the ice thickness reduction in a range from 0.2 m up to 0.6 m, and the change maximum falls for the summer season of intensive melting. The spatial distribution of ice thickness changes shows, that on the large part of the Arctic Ocean there was a reduction of ice thickness down to 1 m. However, there is also an area of some increase of the ice layer basically in a range up to 0.2 m (Beaufort Sea. The 0.05 decrease of sea ice snow albedo leads to reduction of average ice thickness approximately by 0.2 m, and this value slightly depends on a season. In the following experiment the ocean – ice thermal interaction influence on the ice cover is estimated. It is carried out by increase of a heat flux from ocean to the bottom surface of sea ice by 2 W/sq. m in comparison with base variant. The analysis demonstrates, that the average ice thickness reduces in a range from 0.2 m to 0.35 m. There are small seasonal changes of this value.The numerical experiments results have shown, that an ice cover and its seasonal evolution rather strongly depend on varied parameters

  12. Surface analysis methods in materials science

    CERN Document Server

    Sexton, Brett; Smart, Roger

    1992-01-01

    The idea for this book stemmed from a remark by Philip Jennings of Murdoch University in a discussion session following a regular meeting of the Australian Surface Science group. He observed that a text on surface analysis and applica­ tions to materials suitable for final year undergraduate and postgraduate science students was not currently available. Furthermore, the members of the Australian Surface Science group had the research experience and range of coverage of sur­ face analytical techniques and applications to provide a text for this purpose. A of techniques and applications to be included was agreed at that meeting. The list intended readership of the book has been broadened since the early discussions, particularly to encompass industrial users, but there has been no significant alter­ ation in content. The editors, in consultation with the contributors, have agreed that the book should be prepared for four major groups of readers: - senior undergraduate students in chemistry, physics, metallur...

  13. A global sensitivity analysis approach for morphogenesis models

    KAUST Repository

    Boas, Sonja E. M.

    2015-11-21

    Background Morphogenesis is a developmental process in which cells organize into shapes and patterns. Complex, non-linear and multi-factorial models with images as output are commonly used to study morphogenesis. It is difficult to understand the relation between the uncertainty in the input and the output of such ‘black-box’ models, giving rise to the need for sensitivity analysis tools. In this paper, we introduce a workflow for a global sensitivity analysis approach to study the impact of single parameters and the interactions between them on the output of morphogenesis models. Results To demonstrate the workflow, we used a published, well-studied model of vascular morphogenesis. The parameters of this cellular Potts model (CPM) represent cell properties and behaviors that drive the mechanisms of angiogenic sprouting. The global sensitivity analysis correctly identified the dominant parameters in the model, consistent with previous studies. Additionally, the analysis provided information on the relative impact of single parameters and of interactions between them. This is very relevant because interactions of parameters impede the experimental verification of the predicted effect of single parameters. The parameter interactions, although of low impact, provided also new insights in the mechanisms of in silico sprouting. Finally, the analysis indicated that the model could be reduced by one parameter. Conclusions We propose global sensitivity analysis as an alternative approach to study the mechanisms of morphogenesis. Comparison of the ranking of the impact of the model parameters to knowledge derived from experimental data and from manipulation experiments can help to falsify models and to find the operand mechanisms in morphogenesis. The workflow is applicable to all ‘black-box’ models, including high-throughput in vitro models in which output measures are affected by a set of experimental perturbations.

  14. A global sensitivity analysis approach for morphogenesis models.

    Science.gov (United States)

    Boas, Sonja E M; Navarro Jimenez, Maria I; Merks, Roeland M H; Blom, Joke G

    2015-11-21

    Morphogenesis is a developmental process in which cells organize into shapes and patterns. Complex, non-linear and multi-factorial models with images as output are commonly used to study morphogenesis. It is difficult to understand the relation between the uncertainty in the input and the output of such 'black-box' models, giving rise to the need for sensitivity analysis tools. In this paper, we introduce a workflow for a global sensitivity analysis approach to study the impact of single parameters and the interactions between them on the output of morphogenesis models. To demonstrate the workflow, we used a published, well-studied model of vascular morphogenesis. The parameters of this cellular Potts model (CPM) represent cell properties and behaviors that drive the mechanisms of angiogenic sprouting. The global sensitivity analysis correctly identified the dominant parameters in the model, consistent with previous studies. Additionally, the analysis provided information on the relative impact of single parameters and of interactions between them. This is very relevant because interactions of parameters impede the experimental verification of the predicted effect of single parameters. The parameter interactions, although of low impact, provided also new insights in the mechanisms of in silico sprouting. Finally, the analysis indicated that the model could be reduced by one parameter. We propose global sensitivity analysis as an alternative approach to study the mechanisms of morphogenesis. Comparison of the ranking of the impact of the model parameters to knowledge derived from experimental data and from manipulation experiments can help to falsify models and to find the operand mechanisms in morphogenesis. The workflow is applicable to all 'black-box' models, including high-throughput in vitro models in which output measures are affected by a set of experimental perturbations.

  15. Important radionuclides and their sensitivity for groundwater pathway of a hypothetical near-surface disposal facility

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. W.; Chang, K.; Kim, C. L. [Nuclear Enviroment Technology Institute, Taejon (Korea, Republic of)

    2001-04-01

    A radiological safety assessment was performed for a hypothetical near-surface radioactive waste repository as a simple screening calculation to identify important nuclides and to provide insights on the data needs for a successful demonstration of compliance. Individual effective doses were calculated for a conservative groundwater pathway scenario considering well drilling near the site boundary. Sensitivity of resulting ingestion dose to input parameter values was also analyzed using Monte Carlo sampling. Considering peak dose rate and assessment timescale, C-14 and I-129 were identified as important nuclides and U-235 and U-238 as potentially important nuclides. For C-14, the does was most sensitive to Darcy velocity in aquifer. The distribution coefficient showed high degree of sensitivity for I-129 release.

  16. Important radionuclides and their sensitivity for groundwater pathway of a hypothetical near-surface disposal facility

    International Nuclear Information System (INIS)

    Park, J. W.; Chang, K.; Kim, C. L.

    2001-01-01

    A radiological safety assessment was performed for a hypothetical near-surface radioactive waste repository as a simple screening calculation to identify important nuclides and to provide insights on the data needs for a successful demonstration of compliance. Individual effective doses were calculated for a conservative groundwater pathway scenario considering well drilling near the site boundary. Sensitivity of resulting ingestion dose to input parameter values was also analyzed using Monte Carlo sampling. Considering peak dose rate and assessment timescale, C-14 and I-129 were identified as important nuclides and U-235 and U-238 as potentially important nuclides. For C-14, the does was most sensitive to Darcy velocity in aquifer. The distribution coefficient showed high degree of sensitivity for I-129 release

  17. Enhanced photovoltaic performance of Sb2S3-sensitized solar cells through surface treatments

    Science.gov (United States)

    Ye, Qing; Xu, Yafeng; Chen, Wenyong; Yang, Shangfeng; Zhu, Jun; Weng, Jian

    2018-05-01

    Efficient antimony sulfide (Sb2S3)-sensitized solar cells were obtained by a sequential treatment with thioacetamide (TA) and 1-decylphosphonic acid (DPA). Compared with the untreated Sb2S3-sensitized solar cells, the power conversion efficiency of the treated Sb2S3 solar cells was improved by 1.80% to 3.23%. The TA treatment improved the Sb2S3 films by reducing impurities and decreasing the film's surface defects, which inhibited the emergence of recombination centers. The DPA treatment reduced the recombination between hole transport materials (HTMs) and the Sb2S3. Therefore, we have presented an efficient strategy to improve the performance of Sb2S3-sensitized solar cells.

  18. The Effect of Ocular Surface Regularity on Contrast Sensitivity and Straylight in Dry Eye

    OpenAIRE

    Koh, Shizuka; Maeda, Naoyuki; Ikeda, Chikako; Asonuma, Sanae; Ogawa, Mai; Hiraoka, Takahiro; Oshika, Tetsuro; Nishida, Kohji

    2017-01-01

    Purpose: To investigate the association between visual function and ocular surface regularity in dry eye.Methods: We enrolled 52 eyes of 52 dry eye patients (34 dry eyes with superficial punctate keratopathy [SPK] in the central corneal region [central SPK] and 18 dry eyes without central SPK) and 20 eyes of 20 normal control subjects. All eyes had a best-corrected distance visual acuity better than 20/20. We measured two indices of contrast sensitivity function under photopic conditions: con...

  19. SENSITIVITY OF BODY SWAY PARAMETERS DURING QUIET STANDING TO MANIPULATION OF SUPPORT SURFACE SIZE

    Directory of Open Access Journals (Sweden)

    Sarabon Nejc

    2010-09-01

    Full Text Available The centre of pressure (COP movement during stance maintenance on a stable surface is commonly used to describe and evaluate static balance. The aim of our study was to test sensitivity of individual COP parameters to different stance positions which were used to address size specific changes in the support surface. Twenty-nine subjects participated in the study. They carried out three 60-second repetitions of each of the five balance tasks (parallel stance, semi-tandem stance, tandem stance, contra-tandem stance, single leg stance. Using the force plate, the monitored parameters included the total COP distance, the distance covered in antero-posterior and medio-lateral directions, the maximum oscillation amplitude in antero-posterior and medio-lateral directions, the total frequency of oscillation, as well as the frequency of oscillation in antero-posterior and medio-lateral directions. The parameters which describe the total COP distance were the most sensitive to changes in the balance task, whereas the frequency of oscillation proved to be sensitive to a slightly lesser extent. Reductions in the support surface size in each of the directions resulted in proportional changes of antero-posterior and medio- lateral directions. The frequency of oscillation did not increase evenly with the increase in the level of difficulty of the balance task, but reached a certain value, above which it did not increase. Our study revealed the monitored parameters of the COP to be sensitive to the support surface size manipulations. The results of the study provide an important source for clinical and research use of the body sway measurements.

  20. Anisotropic analysis for seismic sensitivity of groundwater monitoring wells

    Science.gov (United States)

    Pan, Y.; Hsu, K.

    2011-12-01

    Taiwan is located at the boundaries of Eurasian Plate and the Philippine Sea Plate. The movement of plate causes crustal uplift and lateral deformation to lead frequent earthquakes in the vicinity of Taiwan. The change of groundwater level trigged by earthquake has been observed and studied in Taiwan for many years. The change of groundwater may appear in oscillation and step changes. The former is caused by seismic waves. The latter is caused by the volumetric strain and reflects the strain status. Since the setting of groundwater monitoring well is easier and cheaper than the setting of strain gauge, the groundwater measurement may be used as a indication of stress. This research proposes the concept of seismic sensitivity of groundwater monitoring well and apply to DonHer station in Taiwan. Geostatistical method is used to analysis the anisotropy of seismic sensitivity. GIS is used to map the sensitive area of the existing groundwater monitoring well.

  1. Sensitivity analysis of predictive models with an automated adjoint generator

    International Nuclear Information System (INIS)

    Pin, F.G.; Oblow, E.M.

    1987-01-01

    The adjoint method is a well established sensitivity analysis methodology that is particularly efficient in large-scale modeling problems. The coefficients of sensitivity of a given response with respect to every parameter involved in the modeling code can be calculated from the solution of a single adjoint run of the code. Sensitivity coefficients provide a quantitative measure of the importance of the model data in calculating the final results. The major drawback of the adjoint method is the requirement for calculations of very large numbers of partial derivatives to set up the adjoint equations of the model. ADGEN is a software system that has been designed to eliminate this drawback and automatically implement the adjoint formulation in computer codes. The ADGEN system will be described and its use for improving performance assessments and predictive simulations will be discussed. 8 refs., 1 fig

  2. Sensitivity analysis of time-dependent laminar flows

    International Nuclear Information System (INIS)

    Hristova, H.; Etienne, S.; Pelletier, D.; Borggaard, J.

    2004-01-01

    This paper presents a general sensitivity equation method (SEM) for time dependent incompressible laminar flows. The SEM accounts for complex parameter dependence and is suitable for a wide range of problems. The formulation is verified on a problem with a closed form solution obtained by the method of manufactured solution. Systematic grid convergence studies confirm the theoretical rates of convergence in both space and time. The methodology is then applied to pulsatile flow around a square cylinder. Computations show that the flow starts with symmetrical vortex shedding followed by a transition to the traditional Von Karman street (alternate vortex shedding). Simulations show that the transition phase manifests itself earlier in the sensitivity fields than in the flow field itself. Sensitivities are then demonstrated for fast evaluation of nearby flows and uncertainty analysis. (author)

  3. Computational Methods for Sensitivity and Uncertainty Analysis in Criticality Safety

    International Nuclear Information System (INIS)

    Broadhead, B.L.; Childs, R.L.; Rearden, B.T.

    1999-01-01

    Interest in the sensitivity methods that were developed and widely used in the 1970s (the FORSS methodology at ORNL among others) has increased recently as a result of potential use in the area of criticality safety data validation procedures to define computational bias, uncertainties and area(s) of applicability. Functional forms of the resulting sensitivity coefficients can be used as formal parameters in the determination of applicability of benchmark experiments to their corresponding industrial application areas. In order for these techniques to be generally useful to the criticality safety practitioner, the procedures governing their use had to be updated and simplified. This paper will describe the resulting sensitivity analysis tools that have been generated for potential use by the criticality safety community

  4. Non-parametric correlative uncertainty quantification and sensitivity analysis: Application to a Langmuir bimolecular adsorption model

    Science.gov (United States)

    Feng, Jinchao; Lansford, Joshua; Mironenko, Alexander; Pourkargar, Davood Babaei; Vlachos, Dionisios G.; Katsoulakis, Markos A.

    2018-03-01

    We propose non-parametric methods for both local and global sensitivity analysis of chemical reaction models with correlated parameter dependencies. The developed mathematical and statistical tools are applied to a benchmark Langmuir competitive adsorption model on a close packed platinum surface, whose parameters, estimated from quantum-scale computations, are correlated and are limited in size (small data). The proposed mathematical methodology employs gradient-based methods to compute sensitivity indices. We observe that ranking influential parameters depends critically on whether or not correlations between parameters are taken into account. The impact of uncertainty in the correlation and the necessity of the proposed non-parametric perspective are demonstrated.

  5. Non-parametric correlative uncertainty quantification and sensitivity analysis: Application to a Langmuir bimolecular adsorption model

    Directory of Open Access Journals (Sweden)

    Jinchao Feng

    2018-03-01

    Full Text Available We propose non-parametric methods for both local and global sensitivity analysis of chemical reaction models with correlated parameter dependencies. The developed mathematical and statistical tools are applied to a benchmark Langmuir competitive adsorption model on a close packed platinum surface, whose parameters, estimated from quantum-scale computations, are correlated and are limited in size (small data. The proposed mathematical methodology employs gradient-based methods to compute sensitivity indices. We observe that ranking influential parameters depends critically on whether or not correlations between parameters are taken into account. The impact of uncertainty in the correlation and the necessity of the proposed non-parametric perspective are demonstrated.

  6. Cross Validation Through Two-Dimensional Solution Surface for Cost-Sensitive SVM.

    Science.gov (United States)

    Gu, Bin; Sheng, Victor S; Tay, Keng Yeow; Romano, Walter; Li, Shuo

    2017-06-01

    Model selection plays an important role in cost-sensitive SVM (CS-SVM). It has been proven that the global minimum cross validation (CV) error can be efficiently computed based on the solution path for one parameter learning problems. However, it is a challenge to obtain the global minimum CV error for CS-SVM based on one-dimensional solution path and traditional grid search, because CS-SVM is with two regularization parameters. In this paper, we propose a solution and error surfaces based CV approach (CV-SES). More specifically, we first compute a two-dimensional solution surface for CS-SVM based on a bi-parameter space partition algorithm, which can fit solutions of CS-SVM for all values of both regularization parameters. Then, we compute a two-dimensional validation error surface for each CV fold, which can fit validation errors of CS-SVM for all values of both regularization parameters. Finally, we obtain the CV error surface by superposing K validation error surfaces, which can find the global minimum CV error of CS-SVM. Experiments are conducted on seven datasets for cost sensitive learning and on four datasets for imbalanced learning. Experimental results not only show that our proposed CV-SES has a better generalization ability than CS-SVM with various hybrids between grid search and solution path methods, and than recent proposed cost-sensitive hinge loss SVM with three-dimensional grid search, but also show that CV-SES uses less running time.

  7. Parameter uncertainty effects on variance-based sensitivity analysis

    International Nuclear Information System (INIS)

    Yu, W.; Harris, T.J.

    2009-01-01

    In the past several years there has been considerable commercial and academic interest in methods for variance-based sensitivity analysis. The industrial focus is motivated by the importance of attributing variance contributions to input factors. A more complete understanding of these relationships enables companies to achieve goals related to quality, safety and asset utilization. In a number of applications, it is possible to distinguish between two types of input variables-regressive variables and model parameters. Regressive variables are those that can be influenced by process design or by a control strategy. With model parameters, there are typically no opportunities to directly influence their variability. In this paper, we propose a new method to perform sensitivity analysis through a partitioning of the input variables into these two groupings: regressive variables and model parameters. A sequential analysis is proposed, where first an sensitivity analysis is performed with respect to the regressive variables. In the second step, the uncertainty effects arising from the model parameters are included. This strategy can be quite useful in understanding process variability and in developing strategies to reduce overall variability. When this method is used for nonlinear models which are linear in the parameters, analytical solutions can be utilized. In the more general case of models that are nonlinear in both the regressive variables and the parameters, either first order approximations can be used, or numerically intensive methods must be used

  8. Understanding dynamics using sensitivity analysis: caveat and solution

    Science.gov (United States)

    2011-01-01

    Background Parametric sensitivity analysis (PSA) has become one of the most commonly used tools in computational systems biology, in which the sensitivity coefficients are used to study the parametric dependence of biological models. As many of these models describe dynamical behaviour of biological systems, the PSA has subsequently been used to elucidate important cellular processes that regulate this dynamics. However, in this paper, we show that the PSA coefficients are not suitable in inferring the mechanisms by which dynamical behaviour arises and in fact it can even lead to incorrect conclusions. Results A careful interpretation of parametric perturbations used in the PSA is presented here to explain the issue of using this analysis in inferring dynamics. In short, the PSA coefficients quantify the integrated change in the system behaviour due to persistent parametric perturbations, and thus the dynamical information of when a parameter perturbation matters is lost. To get around this issue, we present a new sensitivity analysis based on impulse perturbations on system parameters, which is named impulse parametric sensitivity analysis (iPSA). The inability of PSA and the efficacy of iPSA in revealing mechanistic information of a dynamical system are illustrated using two examples involving switch activation. Conclusions The interpretation of the PSA coefficients of dynamical systems should take into account the persistent nature of parametric perturbations involved in the derivation of this analysis. The application of PSA to identify the controlling mechanism of dynamical behaviour can be misleading. By using impulse perturbations, introduced at different times, the iPSA provides the necessary information to understand how dynamics is achieved, i.e. which parameters are essential and when they become important. PMID:21406095

  9. Sensitivity Analysis of Deviation Source for Fast Assembly Precision Optimization

    Directory of Open Access Journals (Sweden)

    Jianjun Tang

    2014-01-01

    Full Text Available Assembly precision optimization of complex product has a huge benefit in improving the quality of our products. Due to the impact of a variety of deviation source coupling phenomena, the goal of assembly precision optimization is difficult to be confirmed accurately. In order to achieve optimization of assembly precision accurately and rapidly, sensitivity analysis of deviation source is proposed. First, deviation source sensitivity is defined as the ratio of assembly dimension variation and deviation source dimension variation. Second, according to assembly constraint relations, assembly sequences and locating, deviation transmission paths are established by locating the joints between the adjacent parts, and establishing each part’s datum reference frame. Third, assembly multidimensional vector loops are created using deviation transmission paths, and the corresponding scalar equations of each dimension are established. Then, assembly deviation source sensitivity is calculated by using a first-order Taylor expansion and matrix transformation method. Finally, taking assembly precision optimization of wing flap rocker as an example, the effectiveness and efficiency of the deviation source sensitivity analysis method are verified.

  10. Sensitivity analysis for improving nanomechanical photonic transducers biosensors

    International Nuclear Information System (INIS)

    Fariña, D; Álvarez, M; Márquez, S; Lechuga, L M; Dominguez, C

    2015-01-01

    The achievement of high sensitivity and highly integrated transducers is one of the main challenges in the development of high-throughput biosensors. The aim of this study is to improve the final sensitivity of an opto-mechanical device to be used as a reliable biosensor. We report the analysis of the mechanical and optical properties of optical waveguide microcantilever transducers, and their dependency on device design and dimensions. The selected layout (geometry) based on two butt-coupled misaligned waveguides displays better sensitivities than an aligned one. With this configuration, we find that an optimal microcantilever thickness range between 150 nm and 400 nm would increase both microcantilever bending during the biorecognition process and increase optical sensitivity to 4.8   ×   10 −2  nm −1 , an order of magnitude higher than other similar opto-mechanical devices. Moreover, the analysis shows that a single mode behaviour of the propagating radiation is required to avoid modal interference that could misinterpret the readout signal. (paper)

  11. Surface analysis by RBS and NRA

    International Nuclear Information System (INIS)

    Braun, M.

    1984-01-01

    The use of Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA) for surface analysis is discussed. For the RBS technique, emphasis is laid on cases which are not discussed in existing review articles of the subject. The present work intends to describe a calculation procedure with the aid of which it is possible to obtain the depth distribution of a high concentration and non-homogeneously binary compound sample. This complicates the determination of the stopping and scattering cross-sections of the incoming particles at a certain depth below the surface. In addition, a method is described by which the thickness and composition of a two-element film, deposited on a single-element substrate, can be determined by RBS. One advantage with the method presented here is that it is not necessary to detect any signals from the lighter component of the film, in order to determine the composition. This improves the RBS technique to study light elements in connection with thin layers. Finally, the NRA method to measure concentration distributions of deuterium beneath a surface is presented. In the case discussed here, the analysis is done by the D( 3 He, H) 4 He nuclear reaction. (author)

  12. SENSIT: a cross-section and design sensitivity and uncertainty analysis code. [In FORTRAN for CDC-7600, IBM 360

    Energy Technology Data Exchange (ETDEWEB)

    Gerstl, S.A.W.

    1980-01-01

    SENSIT computes the sensitivity and uncertainty of a calculated integral response (such as a dose rate) due to input cross sections and their uncertainties. Sensitivity profiles are computed for neutron and gamma-ray reaction cross sections of standard multigroup cross section sets and for secondary energy distributions (SEDs) of multigroup scattering matrices. In the design sensitivity mode, SENSIT computes changes in an integral response due to design changes and gives the appropriate sensitivity coefficients. Cross section uncertainty analyses are performed for three types of input data uncertainties: cross-section covariance matrices for pairs of multigroup reaction cross sections, spectral shape uncertainty parameters for secondary energy distributions (integral SED uncertainties), and covariance matrices for energy-dependent response functions. For all three types of data uncertainties SENSIT computes the resulting variance and estimated standard deviation in an integral response of interest, on the basis of generalized perturbation theory. SENSIT attempts to be more comprehensive than earlier sensitivity analysis codes, such as SWANLAKE.

  13. Least Squares Shadowing sensitivity analysis of chaotic limit cycle oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiqi, E-mail: qiqi@mit.edu; Hu, Rui, E-mail: hurui@mit.edu; Blonigan, Patrick, E-mail: blonigan@mit.edu

    2014-06-15

    The adjoint method, among other sensitivity analysis methods, can fail in chaotic dynamical systems. The result from these methods can be too large, often by orders of magnitude, when the result is the derivative of a long time averaged quantity. This failure is known to be caused by ill-conditioned initial value problems. This paper overcomes this failure by replacing the initial value problem with the well-conditioned “least squares shadowing (LSS) problem”. The LSS problem is then linearized in our sensitivity analysis algorithm, which computes a derivative that converges to the derivative of the infinitely long time average. We demonstrate our algorithm in several dynamical systems exhibiting both periodic and chaotic oscillations.

  14. Therapeutic Implications from Sensitivity Analysis of Tumor Angiogenesis Models

    Science.gov (United States)

    Poleszczuk, Jan; Hahnfeldt, Philip; Enderling, Heiko

    2015-01-01

    Anti-angiogenic cancer treatments induce tumor starvation and regression by targeting the tumor vasculature that delivers oxygen and nutrients. Mathematical models prove valuable tools to study the proof-of-concept, efficacy and underlying mechanisms of such treatment approaches. The effects of parameter value uncertainties for two models of tumor development under angiogenic signaling and anti-angiogenic treatment are studied. Data fitting is performed to compare predictions of both models and to obtain nominal parameter values for sensitivity analysis. Sensitivity analysis reveals that the success of different cancer treatments depends on tumor size and tumor intrinsic parameters. In particular, we show that tumors with ample vascular support can be successfully targeted with conventional cytotoxic treatments. On the other hand, tumors with curtailed vascular support are not limited by their growth rate and therefore interruption of neovascularization emerges as the most promising treatment target. PMID:25785600

  15. Global sensitivity analysis of multiscale properties of porous materials

    Science.gov (United States)

    Um, Kimoon; Zhang, Xuan; Katsoulakis, Markos; Plechac, Petr; Tartakovsky, Daniel M.

    2018-02-01

    Ubiquitous uncertainty about pore geometry inevitably undermines the veracity of pore- and multi-scale simulations of transport phenomena in porous media. It raises two fundamental issues: sensitivity of effective material properties to pore-scale parameters and statistical parameterization of Darcy-scale models that accounts for pore-scale uncertainty. Homogenization-based maps of pore-scale parameters onto their Darcy-scale counterparts facilitate both sensitivity analysis (SA) and uncertainty quantification. We treat uncertain geometric characteristics of a hierarchical porous medium as random variables to conduct global SA and to derive probabilistic descriptors of effective diffusion coefficients and effective sorption rate. Our analysis is formulated in terms of solute transport diffusing through a fluid-filled pore space, while sorbing to the solid matrix. Yet it is sufficiently general to be applied to other multiscale porous media phenomena that are amenable to homogenization.

  16. Sensitivity analysis overlaps of friction elements in cartridge seals

    Directory of Open Access Journals (Sweden)

    Žmindák Milan

    2018-01-01

    Full Text Available Cartridge seals are self-contained units consisting of a shaft sleeve, seals, and gland plate. The applications of mechanical seals are numerous. The most common example of application is in bearing production for automobile industry. This paper deals with the sensitivity analysis of overlaps friction elements in cartridge seal and their influence on the friction torque sealing and compressive force. Furthermore, it describes materials for the manufacture of sealings, approaches usually used to solution of hyperelastic materials by FEM and short introduction into the topic wheel bearings. The practical part contains one of the approach for measurement friction torque, which results were used to specifying the methodology and precision of FEM calculation realized by software ANSYS WORKBENCH. This part also contains the sensitivity analysis of overlaps friction elements.

  17. An overview of the design and analysis of simulation experiments for sensitivity analysis

    NARCIS (Netherlands)

    Kleijnen, J.P.C.

    2005-01-01

    Sensitivity analysis may serve validation, optimization, and risk analysis of simulation models. This review surveys 'classic' and 'modern' designs for experiments with simulation models. Classic designs were developed for real, non-simulated systems in agriculture, engineering, etc. These designs

  18. Sensitivity Analysis of the Scattering-Based SARBM3D Despeckling Algorithm.

    Science.gov (United States)

    Di Simone, Alessio

    2016-06-25

    Synthetic Aperture Radar (SAR) imagery greatly suffers from multiplicative speckle noise, typical of coherent image acquisition sensors, such as SAR systems. Therefore, a proper and accurate despeckling preprocessing step is almost mandatory to aid the interpretation and processing of SAR data by human users and computer algorithms, respectively. Very recently, a scattering-oriented version of the popular SAR Block-Matching 3D (SARBM3D) despeckling filter, named Scattering-Based (SB)-SARBM3D, was proposed. The new filter is based on the a priori knowledge of the local topography of the scene. In this paper, an experimental sensitivity analysis of the above-mentioned despeckling algorithm is carried out, and the main results are shown and discussed. In particular, the role of both electromagnetic and geometrical parameters of the surface and the impact of its scattering behavior are investigated. Furthermore, a comprehensive sensitivity analysis of the SB-SARBM3D filter against the Digital Elevation Model (DEM) resolution and the SAR image-DEM coregistration step is also provided. The sensitivity analysis shows a significant robustness of the algorithm against most of the surface parameters, while the DEM resolution plays a key role in the despeckling process. Furthermore, the SB-SARBM3D algorithm outperforms the original SARBM3D in the presence of the most realistic scattering behaviors of the surface. An actual scenario is also presented to assess the DEM role in real-life conditions.

  19. A sensitivity analysis for a thermomechanical model of the Antarctic ice sheet and ice shelves

    Science.gov (United States)

    Baratelli, F.; Castellani, G.; Vassena, C.; Giudici, M.

    2012-04-01

    The outcomes of an ice sheet model depend on a number of parameters and physical quantities which are often estimated with large uncertainty, because of lack of sufficient experimental measurements in such remote environments. Therefore, the efforts to improve the accuracy of the predictions of ice sheet models by including more physical processes and interactions with atmosphere, hydrosphere and lithosphere can be affected by the inaccuracy of the fundamental input data. A sensitivity analysis can help to understand which are the input data that most affect the different predictions of the model. In this context, a finite difference thermomechanical ice sheet model based on the Shallow-Ice Approximation (SIA) and on the Shallow-Shelf Approximation (SSA) has been developed and applied for the simulation of the evolution of the Antarctic ice sheet and ice shelves for the last 200 000 years. The sensitivity analysis of the model outcomes (e.g., the volume of the ice sheet and of the ice shelves, the basal melt rate of the ice sheet, the mean velocity of the Ross and Ronne-Filchner ice shelves, the wet area at the base of the ice sheet) with respect to the model parameters (e.g., the basal sliding coefficient, the geothermal heat flux, the present-day surface accumulation and temperature, the mean ice shelves viscosity, the melt rate at the base of the ice shelves) has been performed by computing three synthetic numerical indices: two local sensitivity indices and a global sensitivity index. Local sensitivity indices imply a linearization of the model and neglect both non-linear and joint effects of the parameters. The global variance-based sensitivity index, instead, takes into account the complete variability of the input parameters but is usually conducted with a Monte Carlo approach which is computationally very demanding for non-linear complex models. Therefore, the global sensitivity index has been computed using a development of the model outputs in a

  20. UV sensitivity of planktonic net community production in ocean surface waters

    Science.gov (United States)

    Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-05-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

  1. Probabilistic Sensitivities for Fatigue Analysis of Turbine Engine Disks

    OpenAIRE

    Harry R. Millwater; R. Wesley Osborn

    2006-01-01

    A methodology is developed and applied that determines the sensitivities of the probability-of-fracture of a gas turbine disk fatigue analysis with respect to the parameters of the probability distributions describing the random variables. The disk material is subject to initial anomalies, in either low- or high-frequency quantities, such that commonly used materials (titanium, nickel, powder nickel) and common damage mechanisms (inherent defects or su...

  2. Influence analysis to assess sensitivity of the dropout process

    OpenAIRE

    Molenberghs, Geert; Verbeke, Geert; Thijs, Herbert; Lesaffre, Emmanuel; Kenward, Michael

    2001-01-01

    Diggle and Kenward (Appl. Statist. 43 (1994) 49) proposed a selection model for continuous longitudinal data subject to possible non-random dropout. It has provoked a large debate about the role for such models. The original enthusiasm was followed by skepticism about the strong but untestable assumption upon which this type of models invariably rests. Since then, the view has emerged that these models should ideally be made part of a sensitivity analysis. One of their examples is a set of da...

  3. Synthesis, Characterization, and Sensitivity Analysis of Urea Nitrate (UN)

    Science.gov (United States)

    2015-04-01

    determined. From the results of the study, UN is safe to store under normal operating conditions. 15. SUBJECT TERMS urea, nitrate , sensitivity, thermal ...HNO3). Due to its simple composition, ease of manufacture, and higher detonation parameters than ammonium nitrate , it has become one of the...an H50 value of 10.054 ± 0.620 inches. 5. Conclusions From the results of the thermal analysis study, it can be concluded that urea nitrate is

  4. Applications of the TSUNAMI sensitivity and uncertainty analysis methodology

    International Nuclear Information System (INIS)

    Rearden, Bradley T.; Hopper, Calvin M.; Elam, Karla R.; Goluoglu, Sedat; Parks, Cecil V.

    2003-01-01

    The TSUNAMI sensitivity and uncertainty analysis tools under development for the SCALE code system have recently been applied in four criticality safety studies. TSUNAMI is used to identify applicable benchmark experiments for criticality code validation, assist in the design of new critical experiments for a particular need, reevaluate previously computed computational biases, and assess the validation coverage and propose a penalty for noncoverage for a specific application. (author)

  5. Surface Properties of TNOs: Preliminary Statistical Analysis

    Science.gov (United States)

    Antonieta Barucci, Maria; Fornasier, S.; Alvarez-Cantal, A.; de Bergh, C.; Merlin, F.; DeMeo, F.; Dumas, C.

    2009-09-01

    An overview of the surface properties based on the last results obtained during the Large Program performed at ESO-VLT (2007-2008) will be presented. Simultaneous high quality visible and near-infrared spectroscopy and photometry have been carried out on 40 objects with various dynamical properties, using FORS1 (V), ISAAC (J) and SINFONI (H+K bands) mounted respectively at UT2, UT1 and UT4 VLT-ESO telescopes (Cerro Paranal, Chile). For spectroscopy we computed the spectral slope for each object and searched for possible rotational inhomogeneities. A few objects show features in their visible spectra such as Eris, whose spectral bands are displaced with respect to pure methane-ice. We identify new faint absorption features on 10199 Chariklo and 42355 Typhon, possibly due to the presence of aqueous altered materials. The H+K band spectroscopy was performed with the new instrument SINFONI which is a 3D integral field spectrometer. While some objects show no diagnostic spectral bands, others reveal surface deposits of ices of H2O, CH3OH, CH4, and N2. To investigate the surface properties of these bodies, a radiative transfer model has been applied to interpret the entire 0.4-2.4 micron spectral region. The diversity of the spectra suggests that these objects represent a substantial range of bulk compositions. These different surface compositions can be diagnostic of original compositional diversity, interior source and/or different evolution with different physical processes affecting the surfaces. A statistical analysis is in progress to investigate the correlation of the TNOs’ surface properties with size and dynamical properties.

  6. Sensitivity of biogenic volatile organic compounds to land surface parameterizations and vegetation distributions in California

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chun; Huang, Maoyi; Fast, Jerome D.; Berg, Larry K.; Qian, Yun; Guenther, Alex; Gu, Dasa; Shrivastava, Manish; Liu, Ying; Walters, Stacy; Pfister, Gabriele; Jin, Jiming; Shilling, John E.; Warneke, Carsten

    2016-01-01

    Current climate models still have large uncertainties in estimating biogenic trace gases, which can significantly affect atmospheric chemistry and secondary aerosol formation that ultimately influences air quality and aerosol radiative forcing. These uncertainties result from many factors, including uncertainties in land surface processes and specification of vegetation types, both of which can affect the simulated near-surface fluxes of biogenic volatile organic compounds (BVOCs). In this study, the latest version of Model of Emissions of Gases and Aerosols from Nature (MEGAN v2.1) is coupled within the land surface scheme CLM4 (Community Land Model version 4.0) in the Weather Research and Forecasting model with chemistry (WRF-Chem). In this implementation, MEGAN v2.1 shares a consistent vegetation map with CLM4 for estimating BVOC emissions. This is unlike MEGAN v2.0 in the public version of WRF-Chem that uses a stand-alone vegetation map that differs from what is used by land surface schemes. This improved modeling framework is used to investigate the impact of two land surface schemes, CLM4 and Noah, on BVOCs and examine the sensitivity of BVOCs to vegetation distributions in California. The measurements collected during the Carbonaceous Aerosol and Radiative Effects Study (CARES) and the California Nexus of Air Quality and Climate Experiment (CalNex) conducted in June of 2010 provided an opportunity to evaluate the simulated BVOCs. Sensitivity experiments show that land surface schemes do influence the simulated BVOCs, but the impact is much smaller than that of vegetation distributions. This study indicates that more effort is needed to obtain the most appropriate and accurate land cover data sets for climate and air quality models in terms of simulating BVOCs, oxidant chemistry and, consequently, secondary organic aerosol formation.

  7. Classifying multi-model wheat yield impact response surfaces showing sensitivity to temperature and precipitation change

    Czech Academy of Sciences Publication Activity Database

    Fronzek, S.; Pirttioja, N. K.; Carter, T. R.; Bindi, M.; Hoffmann, H.; Palosuo, T.; Ruiz-Ramos, M.; Tao, F.; Trnka, Miroslav; Acutis, M.; Asseng, S.; Baranowski, P.; Basso, B.; Bodin, P.; Buis, S.; Cammarano, D.; Deligios, P.; Destain, M. F.; Dumont, B.; Ewert, F.; Ferrise, R.; Francois, L.; Gaiser, T.; Hlavinka, Petr; Jacquemin, I.; Kersebaum, K. C.; Kollas, C.; Krzyszczak, J.; Lorite, I. J.; Minet, J.; Ines Minguez, M.; Montesino, M.; Moriondo, M.; Mueller, C.; Nendel, C.; Öztürk, I.; Perego, A.; Rodriguez, A.; Ruane, A. C.; Ruget, F.; Sanna, M.; Semenov, M. A.; Slawinski, C.; Stratonovitch, P.; Supit, I.; Waha, K.; Wang, E.; Wu, L.; Zhao, Z.; Rötter, R.

    2018-01-01

    Roč. 159, jan (2018), s. 209-224 ISSN 0308-521X Institutional support: RVO:86652079 Keywords : climate - change * crop models * probabilistic assessment * simulating impacts * british catchments * uncertainty * europe * productivity * calibration * adaptation * Classification * Climate change * Crop model * Ensemble * Sensitivity analysis * Wheat Subject RIV: GC - Agronomy OBOR OECD: Agronomy, plant breeding and plant protection Impact factor: 2.571, year: 2016

  8. Global sensitivity analysis using a Gaussian Radial Basis Function metamodel

    International Nuclear Information System (INIS)

    Wu, Zeping; Wang, Donghui; Okolo N, Patrick; Hu, Fan; Zhang, Weihua

    2016-01-01

    Sensitivity analysis plays an important role in exploring the actual impact of adjustable parameters on response variables. Amongst the wide range of documented studies on sensitivity measures and analysis, Sobol' indices have received greater portion of attention due to the fact that they can provide accurate information for most models. In this paper, a novel analytical expression to compute the Sobol' indices is derived by introducing a method which uses the Gaussian Radial Basis Function to build metamodels of computationally expensive computer codes. Performance of the proposed method is validated against various analytical functions and also a structural simulation scenario. Results demonstrate that the proposed method is an efficient approach, requiring a computational cost of one to two orders of magnitude less when compared to the traditional Quasi Monte Carlo-based evaluation of Sobol' indices. - Highlights: • RBF based sensitivity analysis method is proposed. • Sobol' decomposition of Gaussian RBF metamodel is obtained. • Sobol' indices of Gaussian RBF metamodel are derived based on the decomposition. • The efficiency of proposed method is validated by some numerical examples.

  9. Systemization of burnup sensitivity analysis code (2) (Contract research)

    International Nuclear Information System (INIS)

    Tatsumi, Masahiro; Hyoudou, Hideaki

    2008-08-01

    Towards the practical use of fast reactors, it is a very important subject to improve prediction accuracy for neutronic properties in LMFBR cores from the viewpoint of improvements on plant economic efficiency with rationally high performance cores and that on reliability and safety margins. A distinct improvement on accuracy in nuclear core design has been accomplished by the development of adjusted nuclear library using the cross-section adjustment method, in which the results of critical experiments of JUPITER and so on are reflected. In the design of large LMFBR cores, however, it is important to accurately estimate not only neutronic characteristics, for example, reaction rate distribution and control rod worth but also burnup characteristics, for example, burnup reactivity loss, breeding ratio and so on. For this purpose, it is desired to improve prediction accuracy of burnup characteristics using the data widely obtained in actual core such as the experimental fast reactor 'JOYO'. The analysis of burnup characteristic is needed to effectively use burnup characteristics data in the actual cores based on the cross-section adjustment method. So far, a burnup sensitivity analysis code, SAGEP-BURN, has been developed and confirmed its effectiveness. However, there is a problem that analysis sequence become inefficient because of a big burden to users due to complexity of the theory of burnup sensitivity and limitation of the system. It is also desired to rearrange the system for future revision since it is becoming difficult to implement new functions in the existing large system. It is not sufficient to unify each computational component for the following reasons: the computational sequence may be changed for each item being analyzed or for purpose such as interpretation of physical meaning. Therefore, it is needed to systemize the current code for burnup sensitivity analysis with component blocks of functionality that can be divided or constructed on occasion

  10. Sensitivity analysis in multiple imputation in effectiveness studies of psychotherapy.

    Science.gov (United States)

    Crameri, Aureliano; von Wyl, Agnes; Koemeda, Margit; Schulthess, Peter; Tschuschke, Volker

    2015-01-01

    The importance of preventing and treating incomplete data in effectiveness studies is nowadays emphasized. However, most of the publications focus on randomized clinical trials (RCT). One flexible technique for statistical inference with missing data is multiple imputation (MI). Since methods such as MI rely on the assumption of missing data being at random (MAR), a sensitivity analysis for testing the robustness against departures from this assumption is required. In this paper we present a sensitivity analysis technique based on posterior predictive checking, which takes into consideration the concept of clinical significance used in the evaluation of intra-individual changes. We demonstrate the possibilities this technique can offer with the example of irregular longitudinal data collected with the Outcome Questionnaire-45 (OQ-45) and the Helping Alliance Questionnaire (HAQ) in a sample of 260 outpatients. The sensitivity analysis can be used to (1) quantify the degree of bias introduced by missing not at random data (MNAR) in a worst reasonable case scenario, (2) compare the performance of different analysis methods for dealing with missing data, or (3) detect the influence of possible violations to the model assumptions (e.g., lack of normality). Moreover, our analysis showed that ratings from the patient's and therapist's version of the HAQ could significantly improve the predictive value of the routine outcome monitoring based on the OQ-45. Since analysis dropouts always occur, repeated measurements with the OQ-45 and the HAQ analyzed with MI are useful to improve the accuracy of outcome estimates in quality assurance assessments and non-randomized effectiveness studies in the field of outpatient psychotherapy.

  11. B1 -sensitivity analysis of quantitative magnetization transfer imaging.

    Science.gov (United States)

    Boudreau, Mathieu; Stikov, Nikola; Pike, G Bruce

    2018-01-01

    To evaluate the sensitivity of quantitative magnetization transfer (qMT) fitted parameters to B 1 inaccuracies, focusing on the difference between two categories of T 1 mapping techniques: B 1 -independent and B 1 -dependent. The B 1 -sensitivity of qMT was investigated and compared using two T 1 measurement methods: inversion recovery (IR) (B 1 -independent) and variable flip angle (VFA), B 1 -dependent). The study was separated into four stages: 1) numerical simulations, 2) sensitivity analysis of the Z-spectra, 3) healthy subjects at 3T, and 4) comparison using three different B 1 imaging techniques. For typical B 1 variations in the brain at 3T (±30%), the simulations resulted in errors of the pool-size ratio (F) ranging from -3% to 7% for VFA, and -40% to > 100% for IR, agreeing with the Z-spectra sensitivity analysis. In healthy subjects, pooled whole-brain Pearson correlation coefficients for F (comparing measured double angle and nominal flip angle B 1 maps) were ρ = 0.97/0.81 for VFA/IR. This work describes the B 1 -sensitivity characteristics of qMT, demonstrating that it varies substantially on the B 1 -dependency of the T 1 mapping method. Particularly, the pool-size ratio is more robust against B 1 inaccuracies if VFA T 1 mapping is used, so much so that B 1 mapping could be omitted without substantially biasing F. Magn Reson Med 79:276-285, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  12. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces.

    Science.gov (United States)

    Sidabras, Jason W; Varanasi, Shiv K; Mett, Richard R; Swarts, Steven G; Swartz, Harold M; Hyde, James S

    2014-10-01

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg(2+) doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.

  13. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sidabras, Jason W.; Varanasi, Shiv K.; Hyde, James S. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53211 (United States); Mett, Richard R. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53211 (United States); Department of Physics and Chemistry, Milwaukee School of Engineering, Milwaukee, Wisconsin 53202 (United States); Swarts, Steven G. [Department of Radiation Oncology, University of Florida, Gainesville, Florida, 32610 (United States); Swartz, Harold M. [Department of Radiology, Geisel Medical School at Dartmouth, Hanover, New Hampshire 03755 (United States)

    2014-10-15

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg{sup 2+} doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.

  14. Probability and sensitivity analysis of machine foundation and soil interaction

    Directory of Open Access Journals (Sweden)

    Králik J., jr.

    2009-06-01

    Full Text Available This paper deals with the possibility of the sensitivity and probabilistic analysis of the reliability of the machine foundation depending on variability of the soil stiffness, structure geometry and compressor operation. The requirements to design of the foundation under rotating machines increased due to development of calculation method and computer tools. During the structural design process, an engineer has to consider problems of the soil-foundation and foundation-machine interaction from the safety, reliability and durability of structure point of view. The advantages and disadvantages of the deterministic and probabilistic analysis of the machine foundation resistance are discussed. The sensitivity of the machine foundation to the uncertainties of the soil properties due to longtime rotating movement of machine is not negligible for design engineers. On the example of compressor foundation and turbine fy. SIEMENS AG the affectivity of the probabilistic design methodology was presented. The Latin Hypercube Sampling (LHS simulation method for the analysis of the compressor foundation reliability was used on program ANSYS. The 200 simulations for five load cases were calculated in the real time on PC. The probabilistic analysis gives us more complex information about the soil-foundation-machine interaction as the deterministic analysis.

  15. Applied surface analysis of metal materials

    International Nuclear Information System (INIS)

    Weiss, Z.

    1987-01-01

    The applications of surface analytical techniques in the solution of technological problems in metalurgy and engineering are reviewed. Some important application areas such as corrosion, grain boundary segregation and metallurgical coatings are presented together with specific requirements for the type of information which is necessary for solving particular problems. The techniques discussed include: electron spectroscopies (Auger Electron Spectroscopy, Electron Spectroscopy for Chemical Analysis), ion spectroscopies (Secondary Ion Mass Spectrometry, Ion Scattering Spectroscopy), Rutherford Back-Scattering, nuclear reaction analysis, optical methods (Glow Discharge Optical Emission Spectrometry), ellipsometry, infrared and Raman spectroscopy, the Moessbauer spectroscopy and methods of consumptive depth profile analysis. Principles and analytical features of these methods are demonstrated and examples of their applications to metallurgy are taken from recent literature. (author). 4 figs., 2 tabs., 112 refs

  16. High sensitivity, high surface area Enzyme-linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Singh, Harpal; Morita, Takahiro; Suzuki, Yuma; Shimojima, Masayuki; Le Van, An; Sugamata, Masami; Yang, Ming

    2015-01-01

    Enzyme-linked immunosorbent assays (ELISA) are considered the gold standard in the demonstration of various immunological reactions with an application in the detection of infectious diseases such as during outbreaks or in patient care. This study aimed to produce an ELISA-based diagnostic with an increased sensitivity of detection compared to the standard 96-well method in the immunologic diagnosis of infectious diseases. A '3DStack' was developed using readily available, low cost fabrication technologies namely nanoimprinting and press stamping with an increased surface area of 4 to 6 times more compared to 96-well plates. This was achieved by stacking multiple nanoimprinted polymer sheets. The flow of analytes between the sheets was enhanced by rotating the 3DStack and confirmed by Finite-Element (FE) simulation. An Immunoglobulin G (IgG) ELISA for the detection of antibodies in human serum raised against Rubella virus was performed for validation. An improved sensitivity of up to 1.9 folds higher was observed using the 3DStack compared to the standard method. The increased surface area of the 3DStack developed using nanoimprinting and press stamping technologies, and the flow pattern between sheets generated by rotating the 3DStack were potential contributors to a more sensitive ELISA-based diagnostic device.

  17. Global Sensitivity Analysis for multivariate output using Polynomial Chaos Expansion

    International Nuclear Information System (INIS)

    Garcia-Cabrejo, Oscar; Valocchi, Albert

    2014-01-01

    Many mathematical and computational models used in engineering produce multivariate output that shows some degree of correlation. However, conventional approaches to Global Sensitivity Analysis (GSA) assume that the output variable is scalar. These approaches are applied on each output variable leading to a large number of sensitivity indices that shows a high degree of redundancy making the interpretation of the results difficult. Two approaches have been proposed for GSA in the case of multivariate output: output decomposition approach [9] and covariance decomposition approach [14] but they are computationally intensive for most practical problems. In this paper, Polynomial Chaos Expansion (PCE) is used for an efficient GSA with multivariate output. The results indicate that PCE allows efficient estimation of the covariance matrix and GSA on the coefficients in the approach defined by Campbell et al. [9], and the development of analytical expressions for the multivariate sensitivity indices defined by Gamboa et al. [14]. - Highlights: • PCE increases computational efficiency in 2 approaches of GSA of multivariate output. • Efficient estimation of covariance matrix of output from coefficients of PCE. • Efficient GSA on coefficients of orthogonal decomposition of the output using PCE. • Analytical expressions of multivariate sensitivity indices from coefficients of PCE

  18. Parametric Sensitivity Analysis of the WAVEWATCH III Model

    Directory of Open Access Journals (Sweden)

    Beng-Chun Lee

    2009-01-01

    Full Text Available The parameters in numerical wave models need to be calibrated be fore a model can be applied to a specific region. In this study, we selected the 8 most important parameters from the source term of the WAVEWATCH III model and subjected them to sensitivity analysis to evaluate the sensitivity of the WAVEWATCH III model to the selected parameters to determine how many of these parameters should be considered for further discussion, and to justify the significance priority of each parameter. After ranking each parameter by sensitivity and assessing their cumulative impact, we adopted the ARS method to search for the optimal values of those parameters to which the WAVEWATCH III model is most sensitive by comparing modeling results with ob served data at two data buoys off the coast of north eastern Taiwan; the goal being to find optimal parameter values for improved modeling of wave development. The procedure adopting optimal parameters in wave simulations did improve the accuracy of the WAVEWATCH III model in comparison to default runs based on field observations at two buoys.

  19. ADGEN: a system for automated sensitivity analysis of predictive models

    International Nuclear Information System (INIS)

    Pin, F.G.; Horwedel, J.E.; Oblow, E.M.; Lucius, J.L.

    1987-01-01

    A system that can automatically enhance computer codes with a sensitivity calculation capability is presented. With this new system, named ADGEN, rapid and cost-effective calculation of sensitivities can be performed in any FORTRAN code for all input data or parameters. The resulting sensitivities can be used in performance assessment studies related to licensing or interactions with the public to systematically and quantitatively prove the relative importance of each of the system parameters in calculating the final performance results. A general procedure calling for the systematic use of sensitivities in assessment studies is presented. The procedure can be used in modeling and model validation studies to avoid over modeling, in site characterization planning to avoid over collection of data, and in performance assessments to determine the uncertainties on the final calculated results. The added capability to formally perform the inverse problem, i.e., to determine the input data or parameters on which to focus to determine the input data or parameters on which to focus additional research or analysis effort in order to improve the uncertainty of the final results, is also discussed. 7 references, 2 figures

  20. ADGEN: a system for automated sensitivity analysis of predictive models

    International Nuclear Information System (INIS)

    Pin, F.G.; Horwedel, J.E.; Oblow, E.M.; Lucius, J.L.

    1986-09-01

    A system that can automatically enhance computer codes with a sensitivity calculation capability is presented. With this new system, named ADGEN, rapid and cost-effective calculation of sensitivities can be performed in any FORTRAN code for all input data or parameters. The resulting sensitivities can be used in performance assessment studies related to licensing or interactions with the public to systematically and quantitatively prove the relative importance of each of the system parameters in calculating the final performance results. A general procedure calling for the systematic use of sensitivities in assessment studies is presented. The procedure can be used in modelling and model validation studies to avoid ''over modelling,'' in site characterization planning to avoid ''over collection of data,'' and in performance assessment to determine the uncertainties on the final calculated results. The added capability to formally perform the inverse problem, i.e., to determine the input data or parameters on which to focus additional research or analysis effort in order to improve the uncertainty of the final results, is also discussed

  1. Sensitivity analysis: Interaction of DOE SNF and packaging materials

    International Nuclear Information System (INIS)

    Anderson, P.A.; Kirkham, R.J.; Shaber, E.L.

    1999-01-01

    A sensitivity analysis was conducted to evaluate the technical issues pertaining to possible destructive interactions between spent nuclear fuels (SNFs) and the stainless steel canisters. When issues are identified through such an analysis, they provide the technical basis for answering what if questions and, if needed, for conducting additional analyses, testing, or other efforts to resolve them in order to base the licensing on solid technical grounds. The analysis reported herein systematically assessed the chemical and physical properties and the potential interactions of the materials that comprise typical US Department of Energy (DOE) SNFs and the stainless steel canisters in which they will be stored, transported, and placed in a geologic repository for final disposition. The primary focus in each step of the analysis was to identify any possible phenomena that could potentially compromise the structural integrity of the canisters and to assess their thermodynamic feasibility

  2. Three-dimensional optimization and sensitivity analysis of dental implant thread parameters using finite element analysis.

    Science.gov (United States)

    Geramizadeh, Maryam; Katoozian, Hamidreza; Amid, Reza; Kadkhodazadeh, Mahdi

    2018-04-01

    This study aimed to optimize the thread depth and pitch of a recently designed dental implant to provide uniform stress distribution by means of a response surface optimization method available in finite element (FE) software. The sensitivity of simulation to different mechanical parameters was also evaluated. A three-dimensional model of a tapered dental implant with micro-threads in the upper area and V-shaped threads in the rest of the body was modeled and analyzed using finite element analysis (FEA). An axial load of 100 N was applied to the top of the implants. The model was optimized for thread depth and pitch to determine the optimal stress distribution. In this analysis, micro-threads had 0.25 to 0.3 mm depth and 0.27 to 0.33 mm pitch, and V-shaped threads had 0.405 to 0.495 mm depth and 0.66 to 0.8 mm pitch. The optimized depth and pitch were 0.307 and 0.286 mm for micro-threads and 0.405 and 0.808 mm for V-shaped threads, respectively. In this design, the most effective parameters on stress distribution were the depth and pitch of the micro-threads based on sensitivity analysis results. Based on the results of this study, the optimal implant design has micro-threads with 0.307 and 0.286 mm depth and pitch, respectively, in the upper area and V-shaped threads with 0.405 and 0.808 mm depth and pitch in the rest of the body. These results indicate that micro-thread parameters have a greater effect on stress and strain values.

  3. Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report

    International Nuclear Information System (INIS)

    1999-06-01

    The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites

  4. Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)

    1999-06-01

    The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites.

  5. Recent advances in surface plasmon resonance imaging: detection speed, sensitivity, and portability

    Directory of Open Access Journals (Sweden)

    Zeng Youjun

    2017-06-01

    Full Text Available Surface plasmon resonance (SPR biosensor is a powerful tool for studying the kinetics of biomolecular interactions because they offer unique real-time and label-free measurement capabilities with high detection sensitivity. In the past two decades, SPR technology has been successfully commercialized and its performance has continuously been improved with lots of engineering efforts. In this review, we describe the recent advances in SPR technologies. The developments of SPR technologies focusing on detection speed, sensitivity, and portability are discussed in details. The incorporation of imaging techniques into SPR sensing is emphasized. In addition, our SPR imaging biosensors based on the scanning of wavelength by a solid-state tunable wavelength filter are highlighted. Finally, significant advances of the vast developments in nanotechnology-associated SPR sensing for sensitivity enhancements are also reviewed. It is hoped that this review will provide some insights for researchers who are interested in SPR sensing, and help them develop SPR sensors with better sensitivity and higher throughput.

  6. Recent advances in surface plasmon resonance imaging: detection speed, sensitivity, and portability

    Science.gov (United States)

    Zeng, Youjun; Hu, Rui; Wang, Lei; Gu, Dayong; He, Jianan; Wu, Shu-Yuen; Ho, Ho-Pui; Li, Xuejin; Qu, Junle; Gao, Bruce Zhi; Shao, Yonghong

    2017-06-01

    Surface plasmon resonance (SPR) biosensor is a powerful tool for studying the kinetics of biomolecular interactions because they offer unique real-time and label-free measurement capabilities with high detection sensitivity. In the past two decades, SPR technology has been successfully commercialized and its performance has continuously been improved with lots of engineering efforts. In this review, we describe the recent advances in SPR technologies. The developments of SPR technologies focusing on detection speed, sensitivity, and portability are discussed in details. The incorporation of imaging techniques into SPR sensing is emphasized. In addition, our SPR imaging biosensors based on the scanning of wavelength by a solid-state tunable wavelength filter are highlighted. Finally, significant advances of the vast developments in nanotechnology-associated SPR sensing for sensitivity enhancements are also reviewed. It is hoped that this review will provide some insights for researchers who are interested in SPR sensing, and help them develop SPR sensors with better sensitivity and higher throughput.

  7. Mixed kernel function support vector regression for global sensitivity analysis

    Science.gov (United States)

    Cheng, Kai; Lu, Zhenzhou; Wei, Yuhao; Shi, Yan; Zhou, Yicheng

    2017-11-01

    Global sensitivity analysis (GSA) plays an important role in exploring the respective effects of input variables on an assigned output response. Amongst the wide sensitivity analyses in literature, the Sobol indices have attracted much attention since they can provide accurate information for most models. In this paper, a mixed kernel function (MKF) based support vector regression (SVR) model is employed to evaluate the Sobol indices at low computational cost. By the proposed derivation, the estimation of the Sobol indices can be obtained by post-processing the coefficients of the SVR meta-model. The MKF is constituted by the orthogonal polynomials kernel function and Gaussian radial basis kernel function, thus the MKF possesses both the global characteristic advantage of the polynomials kernel function and the local characteristic advantage of the Gaussian radial basis kernel function. The proposed approach is suitable for high-dimensional and non-linear problems. Performance of the proposed approach is validated by various analytical functions and compared with the popular polynomial chaos expansion (PCE). Results demonstrate that the proposed approach is an efficient method for global sensitivity analysis.

  8. Optimizing human activity patterns using global sensitivity analysis.

    Science.gov (United States)

    Fairchild, Geoffrey; Hickmann, Kyle S; Mniszewski, Susan M; Del Valle, Sara Y; Hyman, James M

    2014-12-01

    Implementing realistic activity patterns for a population is crucial for modeling, for example, disease spread, supply and demand, and disaster response. Using the dynamic activity simulation engine, DASim, we generate schedules for a population that capture regular (e.g., working, eating, and sleeping) and irregular activities (e.g., shopping or going to the doctor). We use the sample entropy (SampEn) statistic to quantify a schedule's regularity for a population. We show how to tune an activity's regularity by adjusting SampEn, thereby making it possible to realistically design activities when creating a schedule. The tuning process sets up a computationally intractable high-dimensional optimization problem. To reduce the computational demand, we use Bayesian Gaussian process regression to compute global sensitivity indices and identify the parameters that have the greatest effect on the variance of SampEn. We use the harmony search (HS) global optimization algorithm to locate global optima. Our results show that HS combined with global sensitivity analysis can efficiently tune the SampEn statistic with few search iterations. We demonstrate how global sensitivity analysis can guide statistical emulation and global optimization algorithms to efficiently tune activities and generate realistic activity patterns. Though our tuning methods are applied to dynamic activity schedule generation, they are general and represent a significant step in the direction of automated tuning and optimization of high-dimensional computer simulations.

  9. Sensitivity analysis practices: Strategies for model-based inference

    International Nuclear Information System (INIS)

    Saltelli, Andrea; Ratto, Marco; Tarantola, Stefano; Campolongo, Francesca

    2006-01-01

    Fourteen years after Science's review of sensitivity analysis (SA) methods in 1989 (System analysis at molecular scale, by H. Rabitz) we search Science Online to identify and then review all recent articles having 'sensitivity analysis' as a keyword. In spite of the considerable developments which have taken place in this discipline, of the good practices which have emerged, and of existing guidelines for SA issued on both sides of the Atlantic, we could not find in our review other than very primitive SA tools, based on 'one-factor-at-a-time' (OAT) approaches. In the context of model corroboration or falsification, we demonstrate that this use of OAT methods is illicit and unjustified, unless the model under analysis is proved to be linear. We show that available good practices, such as variance based measures and others, are able to overcome OAT shortcomings and easy to implement. These methods also allow the concept of factors importance to be defined rigorously, thus making the factors importance ranking univocal. We analyse the requirements of SA in the context of modelling, and present best available practices on the basis of an elementary model. We also point the reader to available recipes for a rigorous SA

  10. Sensitivity analysis practices: Strategies for model-based inference

    Energy Technology Data Exchange (ETDEWEB)

    Saltelli, Andrea [Institute for the Protection and Security of the Citizen (IPSC), European Commission, Joint Research Centre, TP 361, 21020 Ispra (Vatican City State, Holy See,) (Italy)]. E-mail: andrea.saltelli@jrc.it; Ratto, Marco [Institute for the Protection and Security of the Citizen (IPSC), European Commission, Joint Research Centre, TP 361, 21020 Ispra (VA) (Italy); Tarantola, Stefano [Institute for the Protection and Security of the Citizen (IPSC), European Commission, Joint Research Centre, TP 361, 21020 Ispra (VA) (Italy); Campolongo, Francesca [Institute for the Protection and Security of the Citizen (IPSC), European Commission, Joint Research Centre, TP 361, 21020 Ispra (VA) (Italy)

    2006-10-15

    Fourteen years after Science's review of sensitivity analysis (SA) methods in 1989 (System analysis at molecular scale, by H. Rabitz) we search Science Online to identify and then review all recent articles having 'sensitivity analysis' as a keyword. In spite of the considerable developments which have taken place in this discipline, of the good practices which have emerged, and of existing guidelines for SA issued on both sides of the Atlantic, we could not find in our review other than very primitive SA tools, based on 'one-factor-at-a-time' (OAT) approaches. In the context of model corroboration or falsification, we demonstrate that this use of OAT methods is illicit and unjustified, unless the model under analysis is proved to be linear. We show that available good practices, such as variance based measures and others, are able to overcome OAT shortcomings and easy to implement. These methods also allow the concept of factors importance to be defined rigorously, thus making the factors importance ranking univocal. We analyse the requirements of SA in the context of modelling, and present best available practices on the basis of an elementary model. We also point the reader to available recipes for a rigorous SA.

  11. Regional and parametric sensitivity analysis of Sobol' indices

    International Nuclear Information System (INIS)

    Wei, Pengfei; Lu, Zhenzhou; Song, Jingwen

    2015-01-01

    Nowadays, utilizing the Monte Carlo estimators for variance-based sensitivity analysis has gained sufficient popularity in many research fields. These estimators are usually based on n+2 sample matrices well designed for computing both the main and total effect indices, where n is the input dimension. The aim of this paper is to use such n+2 sample matrices to investigate how the main and total effect indices change when the uncertainty of the model inputs are reduced. For this purpose, the regional main and total effect functions are defined for measuring the changes on the main and total effect indices when the distribution range of one input is reduced, and the parametric main and total effect functions are introduced to quantify the residual main and total effect indices due to the reduced variance of one input. Monte Carlo estimators are derived for all the developed sensitivity concepts based on the n+2 samples matrices originally used for computing the main and total effect indices, thus no extra computational cost is introduced. The Ishigami function, a nonlinear model and a planar ten-bar structure are utilized for illustrating the developed sensitivity concepts, and for demonstrating the efficiency and accuracy of the derived Monte Carlo estimators. - Highlights: • The regional main and total effect functions are developed. • The parametric main and total effect functions are introduced. • The proposed sensitivity functions are all generalizations of Sobol' indices. • The Monte Carlo estimators are derived for the four sensitivity functions. • The computational cost of the estimators is the same as that of Sobol' indices

  12. A sensitivity analysis of regional and small watershed hydrologic models

    Science.gov (United States)

    Ambaruch, R.; Salomonson, V. V.; Simmons, J. W.

    1975-01-01

    Continuous simulation models of the hydrologic behavior of watersheds are important tools in several practical applications such as hydroelectric power planning, navigation, and flood control. Several recent studies have addressed the feasibility of using remote earth observations as sources of input data for hydrologic models. The objective of the study reported here was to determine how accurately remotely sensed measurements must be to provide inputs to hydrologic models of watersheds, within the tolerances needed for acceptably accurate synthesis of streamflow by the models. The study objective was achieved by performing a series of sensitivity analyses using continuous simulation models of three watersheds. The sensitivity analysis showed quantitatively how variations in each of 46 model inputs and parameters affect simulation accuracy with respect to five different performance indices.

  13. Stochastic sensitivity analysis and Langevin simulation for neural network learning

    International Nuclear Information System (INIS)

    Koda, Masato

    1997-01-01

    A comprehensive theoretical framework is proposed for the learning of a class of gradient-type neural networks with an additive Gaussian white noise process. The study is based on stochastic sensitivity analysis techniques, and formal expressions are obtained for stochastic learning laws in terms of functional derivative sensitivity coefficients. The present method, based on Langevin simulation techniques, uses only the internal states of the network and ubiquitous noise to compute the learning information inherent in the stochastic correlation between noise signals and the performance functional. In particular, the method does not require the solution of adjoint equations of the back-propagation type. Thus, the present algorithm has the potential for efficiently learning network weights with significantly fewer computations. Application to an unfolded multi-layered network is described, and the results are compared with those obtained by using a back-propagation method

  14. An easily implemented static condensation method for structural sensitivity analysis

    Science.gov (United States)

    Gangadharan, S. N.; Haftka, R. T.; Nikolaidis, E.

    1990-01-01

    A black-box approach to static condensation for sensitivity analysis is presented with illustrative examples of a cube and a car structure. The sensitivity of the structural response with respect to joint stiffness parameter is calculated using the direct method, forward-difference, and central-difference schemes. The efficiency of the various methods for identifying joint stiffness parameters from measured static deflections of these structures is compared. The results indicate that the use of static condensation can reduce computation times significantly and the black-box approach is only slightly less efficient than the standard implementation of static condensation. The ease of implementation of the black-box approach recommends it for use with general-purpose finite element codes that do not have a built-in facility for static condensation.

  15. Nuclear data sensitivity/uncertainty analysis for XT-ADS

    International Nuclear Information System (INIS)

    Sugawara, Takanori; Sarotto, Massimo; Stankovskiy, Alexey; Van den Eynde, Gert

    2011-01-01

    Highlights: → The sensitivity and uncertainty analyses were performed to comprehend the reliability of the XT-ADS neutronic design. → The uncertainties deduced from the covariance data for the XT-ADS criticality were 0.94%, 1.9% and 1.1% by the SCALE 44-group, TENDL-2009 and JENDL-3.3 data, respectively. → When the target accuracy of 0.3%Δk for the criticality was considered, the uncertainties did not satisfy it. → To achieve this accuracy, the uncertainties should be improved by experiments under an adequate condition. - Abstract: The XT-ADS, an accelerator-driven system for an experimental demonstration, has been investigated in the framework of IP EUROTRANS FP6 project. In this study, the sensitivity and uncertainty analyses were performed to comprehend the reliability of the XT-ADS neutronic design. For the sensitivity analysis, it was found that the sensitivity coefficients were significantly different by changing the geometry models and calculation codes. For the uncertainty analysis, it was confirmed that the uncertainties deduced from the covariance data varied significantly by changing them. The uncertainties deduced from the covariance data for the XT-ADS criticality were 0.94%, 1.9% and 1.1% by the SCALE 44-group, TENDL-2009 and JENDL-3.3 data, respectively. When the target accuracy of 0.3%Δk for the criticality was considered, the uncertainties did not satisfy it. To achieve this accuracy, the uncertainties should be improved by experiments under an adequate condition.

  16. Uncertainty and sensitivity analysis of the nuclear fuel thermal behavior

    Energy Technology Data Exchange (ETDEWEB)

    Boulore, A., E-mail: antoine.boulore@cea.fr [Commissariat a l' Energie Atomique (CEA), DEN, Fuel Research Department, 13108 Saint-Paul-lez-Durance (France); Struzik, C. [Commissariat a l' Energie Atomique (CEA), DEN, Fuel Research Department, 13108 Saint-Paul-lez-Durance (France); Gaudier, F. [Commissariat a l' Energie Atomique (CEA), DEN, Systems and Structure Modeling Department, 91191 Gif-sur-Yvette (France)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer A complete quantitative method for uncertainty propagation and sensitivity analysis is applied. Black-Right-Pointing-Pointer The thermal conductivity of UO{sub 2} is modeled as a random variable. Black-Right-Pointing-Pointer The first source of uncertainty is the linear heat rate. Black-Right-Pointing-Pointer The second source of uncertainty is the thermal conductivity of the fuel. - Abstract: In the global framework of nuclear fuel behavior simulation, the response of the models describing the physical phenomena occurring during the irradiation in reactor is mainly conditioned by the confidence in the calculated temperature of the fuel. Amongst all parameters influencing the temperature calculation in our fuel rod simulation code (METEOR V2), several sources of uncertainty have been identified as being the most sensitive: thermal conductivity of UO{sub 2}, radial distribution of power in the fuel pellet, local linear heat rate in the fuel rod, geometry of the pellet and thermal transfer in the gap. Expert judgment and inverse methods have been used to model the uncertainty of these parameters using theoretical distributions and correlation matrices. Propagation of these uncertainties in the METEOR V2 code using the URANIE framework and a Monte-Carlo technique has been performed in different experimental irradiations of UO{sub 2} fuel. At every time step of the simulated experiments, we get a temperature statistical distribution which results from the initial distributions of the uncertain parameters. We then can estimate confidence intervals of the calculated temperature. In order to quantify the sensitivity of the calculated temperature to each of the uncertain input parameters and data, we have also performed a sensitivity analysis using the Sobol' indices at first order.

  17. Surface Preparation for Microdebonding Analysis of Composites

    International Nuclear Information System (INIS)

    Kahraman, Ramazan; Mandell, J. F.

    1999-01-01

    The bond strength between fibers and matrix is an essential property of all composite materials and it must be measured accurately to be able to correlate it with the composite behavior. There are several factors affecting its measurement. This paper discusses the polishing and load application aspects of the indentation test technique for fibre-matrix bond strength determination in polymer and ceramic matrix composites. Different polishing procedures are suggested for polymer and ceramic surfaces for obtaining a smooth surface which is a must for the test results to be reliable. The geometry of the fibers tested was also found to affect the analysis results. For best results, fibers with similar size and which are similarly surrounded by other fibers should be tested. Care should be taken during load application on a fiber for the loading probe not to approach the fiber circumference. The force should be applied in a small increments as possible, however starting from a high enough level to prevent fiber breakage due to surface damage from several loading steps. (Author)

  18. Biosphere dose conversion Factor Importance and Sensitivity Analysis

    International Nuclear Information System (INIS)

    M. Wasiolek

    2004-01-01

    This report presents importance and sensitivity analysis for the environmental radiation model for Yucca Mountain, Nevada (ERMYN). ERMYN is a biosphere model supporting the total system performance assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis concerns the output of the model, biosphere dose conversion factors (BDCFs) for the groundwater, and the volcanic ash exposure scenarios. It identifies important processes and parameters that influence the BDCF values and distributions, enhances understanding of the relative importance of the physical and environmental processes on the outcome of the biosphere model, includes a detailed pathway analysis for key radionuclides, and evaluates the appropriateness of selected parameter values that are not site-specific or have large uncertainty

  19. Surface-selective laser sintering of thermolabile polymer particles using water as heating sensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, E N; Krotova, L I; Minaev, N V; Minaeva, S A; Mironov, A V; Popov, V K [Institute on Laser and Information Technologies of the Russian Academy of Sciencies, Troitsk, Moscow (Russian Federation); Bagratashvili, V N [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2015-11-30

    We report the implementation of a novel scheme for surface-selective laser sintering (SSLS) of polymer particles, based on using water as a sensitizer of laser heating and sintering of particles as well as laser radiation at a wavelength of 1.94 μm, corresponding to the strong absorption band of water. A method of sintering powders of poly(lactide-co-glycolide), a hydrophobic bioresorbable polymer, after modifying its surface with an aqueous solution of hyaluronic acid is developed. The sintering thresholds for wetted polymer are by 3 – 4 times lower than those for sintering in air. The presence of water restricts the temperature of the heated polymer, preventing its thermal destruction. Polymer matrices with a developed porous structure are obtained. The proposed SSLS method can be applied to produce bioresorbable polymer matrices for tissue engineering. (interaction of laser radiation with matter. laser plasma)

  20. Spatial resolution in depth-controlled surface sensitive x-ray techniques

    International Nuclear Information System (INIS)

    Yun, W.B.; Viccaro, P.J.

    1992-01-01

    The spatial resolution along the surface normal and the total depth probed are two important parameters in depth-controlled surface sensitive X-ray techniques employing grazing incidence geometry. The two parameters are analyzed in terms of optical properties (refractive indices) of the media involved and parameters of the incident X-ray beam: beam divergence, X-ray energy, and spectral bandwidth. We derive analytical expressions of the required beam divergence and spectral bandwidth of the incident beam as a function of the two parameters. Sample calculations are made for X-ray energies between 0.1 and 100 keV and for solid Be, Cu, and Au, representing material matrices consisting of low, medium, and high atomic number elements. A brief discussion on obtaining the required beam divergence and spectral bandwidth from present X-ray sources and optics is given

  1. Silver-coated Si nanograss as highly sensitive surface-enhanced Raman spectroscopy substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jing; Kuo, Huei Pei; Hu, Min; Li, Zhiyong; Williams, R.S. [Hewlett-Packard Laboratories, Information and Quantum Systems Laboratory, Palo Alto, CA (United States); Ou, Fung Suong [Hewlett-Packard Laboratories, Information and Quantum Systems Laboratory, Palo Alto, CA (United States); Rice University, Department of Applied Physics, Houston, TX (United States); Stickle, William F. [Hewlett-Packard Company, Advanced Diagnostic Lab, Corvallis, OR (United States)

    2009-09-15

    We created novel surface-enhanced Raman spectroscopy (SERS) substrates by metalization (Ag) of Si nanograss prepared by a Bosch process which involves deep reactive ion etching of single crystalline silicon. No template or lithography was needed for making the Si nanograss, thus providing a simple and inexpensive method to achieve highly sensitive large-area SERS substrates. The dependence of the SERS effect on the thickness of the metal deposition and on the surface morphology and topology of the substrate prior to metal deposition was studied in order to optimize the SERS signals. We observed that the Ag-coated Si nanograss can achieve uniform SERS enhancement over large area ({proportional_to}1 cm x 1 cm) with an average EF (enhancement factor) of 4.2 x 10{sup 8} for 4-mercaptophenol probe molecules. (orig.)

  2. Assessing modeled Greenland surface mass balance in the GISS Model E2 and its sensitivity to surface albedo

    Science.gov (United States)

    Alexander, Patrick; LeGrande, Allegra N.; Koenig, Lora S.; Tedesco, Marco; Moustafa, Samiah E.; Ivanoff, Alvaro; Fischer, Robert P.; Fettweis, Xavier

    2016-04-01

    The surface mass balance (SMB) of the Greenland Ice Sheet (GrIS) plays an important role in global sea level change. Regional Climate Models (RCMs) such as the Modèle Atmosphérique Régionale (MAR) have been employed at high spatial resolution with relatively complex physics to simulate ice sheet SMB. Global climate models (GCMs) incorporate less sophisticated physical schemes and provide outputs at a lower spatial resolution, but have the advantage of modeling the interaction between different components of the earth's oceans, climate, and land surface at a global scale. Improving the ability of GCMs to represent ice sheet SMB is important for making predictions of future changes in global sea level. With the ultimate goal of improving SMB simulated by the Goddard Institute for Space Studies (GISS) Model E2 GCM, we compare simulated GrIS SMB against the outputs of the MAR model and radar-derived estimates of snow accumulation. In order to reproduce present-day climate variability in the Model E2 simulation, winds are constrained to match the reanalysis datasets used to force MAR at the lateral boundaries. We conduct a preliminary assessment of the sensitivity of the simulated Model E2 SMB to surface albedo, a parameter that is known to strongly influence SMB. Model E2 albedo is set to a fixed value of 0.8 over the entire ice sheet in the initial configuration of the model (control case). We adjust this fixed value in an ensemble of simulations over a range of 0.4 to 0.8 (roughly the range of observed summer GrIS albedo values) to examine the sensitivity of ice-sheet-wide SMB to albedo. We prescribe albedo from the Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A3 v6 to examine the impact of a more realistic spatial and temporal variations in albedo. An age-dependent snow albedo parameterization is applied, and its impact on SMB relative to observations and the RCM is assessed.

  3. A practical approach to the sensitivity analysis for kinetic Monte Carlo simulation of heterogeneous catalysis

    Science.gov (United States)

    Hoffmann, Max J.; Engelmann, Felix; Matera, Sebastian

    2017-01-01

    Lattice kinetic Monte Carlo simulations have become a vital tool for predictive quality atomistic understanding of complex surface chemical reaction kinetics over a wide range of reaction conditions. In order to expand their practical value in terms of giving guidelines for the atomic level design of catalytic systems, it is very desirable to readily evaluate a sensitivity analysis for a given model. The result of such a sensitivity analysis quantitatively expresses the dependency of the turnover frequency, being the main output variable, on the rate constants entering the model. In the past, the application of sensitivity analysis, such as degree of rate control, has been hampered by its exuberant computational effort required to accurately sample numerical derivatives of a property that is obtained from a stochastic simulation method. In this study, we present an efficient and robust three-stage approach that is capable of reliably evaluating the sensitivity measures for stiff microkinetic models as we demonstrate using the CO oxidation on RuO2(110) as a prototypical reaction. In the first step, we utilize the Fisher information matrix for filtering out elementary processes which only yield negligible sensitivity. Then we employ an estimator based on the linear response theory for calculating the sensitivity measure for non-critical conditions which covers the majority of cases. Finally, we adapt a method for sampling coupled finite differences for evaluating the sensitivity measure for lattice based models. This allows for an efficient evaluation even in critical regions near a second order phase transition that are hitherto difficult to control. The combined approach leads to significant computational savings over straightforward numerical derivatives and should aid in accelerating the nano-scale design of heterogeneous catalysts.

  4. Detailed Analysis of ECMWF Surface Pressure Data

    Science.gov (United States)

    Fagiolini, E.; Schmidt, T.; Schwarz, G.; Zenner, L.

    2012-04-01

    Investigations of temporal variations within the gravity field of the Earth led us to the analysis of common surface pressure data products delivered by ECMWF. We looked into the characteristics of global as well as spatially and temporally confined phenomena being visible in the data. In particular, we were interested in the overall data quality, the local and temporal signal-to-noise ratio of surface pressure data sets, and the identification of irregular data. To this end, we analyzed a time series of a full year of surface pressure operational analysis data and their nominal standard deviations. The use of pressure data on a Gaussian grid data allowed us to remain close to the internal computations at ECMWF during data assimilation. Thus, we circumvented potential interpolation effects that would otherwise occur in cylindrical projections of conventional map products. The results obtained by us demonstrate the identification of a few distinct outliers, data quality effects over land or water and along coastlines as well as neighborhood effects of samples within and outside of the tropics. Small scale neighborhood effects depend on their geographical direction, sampling distance, land or water, and local time. In addition, one notices large scale seasonal effects that are latitude and longitude dependent. As a consequence, we obtain a cause-and-effect survey of pressure data peculiarities. One can then use background corrected pressure data to analyze seasonal effects within given latitude belts. Here time series of pressure data allow the tracking of high and low pressure areas together with the identification of their actual extent, velocity and life time. This information is vital to overall mass transport calculations and the determination of temporally varying gravity fields. However, one has to note that the satellite and ground-based instruments and the assimilation software being used for the pressure calculations will not remain the same over the years

  5. A framework for sensitivity analysis of decision trees.

    Science.gov (United States)

    Kamiński, Bogumił; Jakubczyk, Michał; Szufel, Przemysław

    2018-01-01

    In the paper, we consider sequential decision problems with uncertainty, represented as decision trees. Sensitivity analysis is always a crucial element of decision making and in decision trees it often focuses on probabilities. In the stochastic model considered, the user often has only limited information about the true values of probabilities. We develop a framework for performing sensitivity analysis of optimal strategies accounting for this distributional uncertainty. We design this robust optimization approach in an intuitive and not overly technical way, to make it simple to apply in daily managerial practice. The proposed framework allows for (1) analysis of the stability of the expected-value-maximizing strategy and (2) identification of strategies which are robust with respect to pessimistic/optimistic/mode-favoring perturbations of probabilities. We verify the properties of our approach in two cases: (a) probabilities in a tree are the primitives of the model and can be modified independently; (b) probabilities in a tree reflect some underlying, structural probabilities, and are interrelated. We provide a free software tool implementing the methods described.

  6. Sensitivity Analysis of OECD Benchmark Tests in BISON

    Energy Technology Data Exchange (ETDEWEB)

    Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gamble, Kyle [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schmidt, Rodney C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Williamson, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    This report summarizes a NEAMS (Nuclear Energy Advanced Modeling and Simulation) project focused on sensitivity analysis of a fuels performance benchmark problem. The benchmark problem was defined by the Uncertainty Analysis in Modeling working group of the Nuclear Science Committee, part of the Nuclear Energy Agency of the Organization for Economic Cooperation and Development (OECD ). The benchmark problem involv ed steady - state behavior of a fuel pin in a Pressurized Water Reactor (PWR). The problem was created in the BISON Fuels Performance code. Dakota was used to generate and analyze 300 samples of 17 input parameters defining core boundary conditions, manuf acturing tolerances , and fuel properties. There were 24 responses of interest, including fuel centerline temperatures at a variety of locations and burnup levels, fission gas released, axial elongation of the fuel pin, etc. Pearson and Spearman correlatio n coefficients and Sobol' variance - based indices were used to perform the sensitivity analysis. This report summarizes the process and presents results from this study.

  7. 2D layered insulator hexagonal boron nitride enabled surface passivation in dye sensitized solar cells.

    Science.gov (United States)

    Shanmugam, Mariyappan; Jacobs-Gedrim, Robin; Durcan, Chris; Yu, Bin

    2013-11-21

    A two-dimensional layered insulator, hexagonal boron nitride (h-BN), is demonstrated as a new class of surface passivation materials in dye-sensitized solar cells (DSSCs) to reduce interfacial carrier recombination. We observe ~57% enhancement in the photo-conversion efficiency of the DSSC utilizing h-BN coated semiconductor TiO2 as compared with the device without surface passivation. The h-BN coated TiO2 is characterized by Raman spectroscopy to confirm the presence of highly crystalline, mixed monolayer/few-layer h-BN nanoflakes on the surface of TiO2. The passivation helps to minimize electron-hole recombination at the TiO2/dye/electrolyte interfaces. The DSSC with h-BN passivation exhibits significantly lower dark saturation current in the low forward bias region and higher saturation in the high forward bias region, respectively, suggesting that the interface quality is largely improved without impeding carrier transport at the material interface. The experimental results reveal that the emerging 2D layered insulator could be used for effective surface passivation in solar cell applications attributed to desirable material features such as high crystallinity and self-terminated/dangling-bond-free atomic planes as compared with high-k thin-film dielectrics.

  8. An explanation for the different climate sensitivities of land and ocean surfaces based on the diurnal cycle

    Directory of Open Access Journals (Sweden)

    A. Kleidon

    2017-09-01

    Full Text Available Observations and climate model simulations consistently show a higher climate sensitivity of land surfaces compared to ocean surfaces. Here we show that this difference in temperature sensitivity can be explained by the different means by which the diurnal variation in solar radiation is buffered. While ocean surfaces buffer the diurnal variations by heat storage changes below the surface, land surfaces buffer it mostly by heat storage changes above the surface in the lower atmosphere that are reflected in the diurnal growth of a convective boundary layer. Storage changes below the surface allow the ocean surface–atmosphere system to maintain turbulent fluxes over day and night, while the land surface–atmosphere system maintains turbulent fluxes only during the daytime hours, when the surface is heated by absorption of solar radiation. This shorter duration of turbulent fluxes on land results in a greater sensitivity of the land surface–atmosphere system to changes in the greenhouse forcing because nighttime temperatures are shaped by radiative exchange only, which are more sensitive to changes in greenhouse forcing. We use a simple, analytic energy balance model of the surface–atmosphere system in which turbulent fluxes are constrained by the maximum power limit to estimate the effects of these different means to buffer the diurnal cycle on the resulting temperature sensitivities. The model predicts that land surfaces have a 50 % greater climate sensitivity than ocean surfaces, and that the nighttime temperatures on land increase about twice as much as daytime temperatures because of the absence of turbulent fluxes at night. Both predictions compare very well with observations and CMIP5 climate model simulations. Hence, the greater climate sensitivity of land surfaces can be explained by its buffering of diurnal variations in solar radiation in the lower atmosphere.

  9. SENSITIVITY ANALYSIS FOR SALTSTONE DISPOSAL UNIT COLUMN DEGRADATION ANALYSES

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G.

    2014-10-28

    PORFLOW related analyses supporting a Sensitivity Analysis for Saltstone Disposal Unit (SDU) column degradation were performed. Previous analyses, Flach and Taylor 2014, used a model in which the SDU columns degraded in a piecewise manner from the top and bottom simultaneously. The current analyses employs a model in which all pieces of the column degrade at the same time. Information was extracted from the analyses which may be useful in determining the distribution of Tc-99 in the various SDUs throughout time and in determining flow balances for the SDUs.

  10. Sensitivity analysis and design optimization through automatic differentiation

    International Nuclear Information System (INIS)

    Hovland, Paul D; Norris, Boyana; Strout, Michelle Mills; Bhowmick, Sanjukta; Utke, Jean

    2005-01-01

    Automatic differentiation is a technique for transforming a program or subprogram that computes a function, including arbitrarily complex simulation codes, into one that computes the derivatives of that function. We describe the implementation and application of automatic differentiation tools. We highlight recent advances in the combinatorial algorithms and compiler technology that underlie successful implementation of automatic differentiation tools. We discuss applications of automatic differentiation in design optimization and sensitivity analysis. We also describe ongoing research in the design of language-independent source transformation infrastructures for automatic differentiation algorithms

  11. Analysis of Hydrological Sensitivity for Flood Risk Assessment

    Directory of Open Access Journals (Sweden)

    Sanjay Kumar Sharma

    2018-02-01

    Full Text Available In order for the Indian government to maximize Integrated Water Resource Management (IWRM, the Brahmaputra River has played an important role in the undertaking of the Pilot Basin Study (PBS due to the Brahmaputra River’s annual regional flooding. The selected Kulsi River—a part of Brahmaputra sub-basin—experienced severe floods in 2007 and 2008. In this study, the Rainfall-Runoff-Inundation (RRI hydrological model was used to simulate the recent historical flood in order to understand and improve the integrated flood risk management plan. The ultimate objective was to evaluate the sensitivity of hydrologic simulation using different Digital Elevation Model (DEM resources, coupled with DEM smoothing techniques, with a particular focus on the comparison of river discharge and flood inundation extent. As a result, the sensitivity analysis showed that, among the input parameters, the RRI model is highly sensitive to Manning’s roughness coefficient values for flood plains, followed by the source of the DEM, and then soil depth. After optimizing its parameters, the simulated inundation extent showed that the smoothing filter was more influential than its simulated discharge at the outlet. Finally, the calibrated and validated RRI model simulations agreed well with the observed discharge and the Moderate Imaging Spectroradiometer (MODIS-detected flood extents.

  12. Sensitivity analysis for the effects of multiple unmeasured confounders.

    Science.gov (United States)

    Groenwold, Rolf H H; Sterne, Jonathan A C; Lawlor, Debbie A; Moons, Karel G M; Hoes, Arno W; Tilling, Kate

    2016-09-01

    Observational studies are prone to (unmeasured) confounding. Sensitivity analysis of unmeasured confounding typically focuses on a single unmeasured confounder. The purpose of this study was to assess the impact of multiple (possibly weak) unmeasured confounders. Simulation studies were performed based on parameters estimated from the British Women's Heart and Health Study, including 28 measured confounders and assuming no effect of ascorbic acid intake on mortality. In addition, 25, 50, or 100 unmeasured confounders were simulated, with various mutual correlations and correlations with measured confounders. The correlated unmeasured confounders did not need to be strongly associated with exposure and outcome to substantially bias the exposure-outcome association at interest, provided that there are sufficiently many unmeasured confounders. Correlations between unmeasured confounders, in addition to the strength of their relationship with exposure and outcome, are key drivers of the magnitude of unmeasured confounding and should be considered in sensitivity analyses. However, if the unmeasured confounders are correlated with measured confounders, the bias yielded by unmeasured confounders is partly removed through adjustment for the measured confounders. Discussions of the potential impact of unmeasured confounding in observational studies, and sensitivity analyses to examine this, should focus on the potential for the joint effect of multiple unmeasured confounders to bias results. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. High order effects in cross section sensitivity analysis

    International Nuclear Information System (INIS)

    Greenspan, E.; Karni, Y.; Gilai, D.

    1978-01-01

    Two types of high order effects associated with perturbations in the flux shape are considered: Spectral Fine Structure Effects (SFSE) and non-linearity between changes in performance parameters and data uncertainties. SFSE are investigated in Part I using a simple single resonance model. Results obtained for each of the resolved and for representative unresolved resonances of 238 U in a ZPR-6/7 like environment indicate that SFSE can have a significant contribution to the sensitivity of group constants to resonance parameters. Methods to account for SFSE both for the propagation of uncertainties and for the adjustment of nuclear data are discussed. A Second Order Sensitivity Theory (SOST) is presented, and its accuracy relative to that of the first order sensitivity theory and of the direct substitution method is investigated in Part II. The investigation is done for the non-linear problem of the effect of changes in the 297 keV sodium minimum cross section on the transport of neutrons in a deep-penetration problem. It is found that the SOST provides a satisfactory accuracy for cross section uncertainty analysis. For the same degree of accuracy, the SOST can be significantly more efficient than the direct substitution method

  14. Accuracy and sensitivity analysis on seismic anisotropy parameter estimation

    Science.gov (United States)

    Yan, Fuyong; Han, De-Hua

    2018-04-01

    There is significant uncertainty in measuring the Thomsen’s parameter δ in laboratory even though the dimensions and orientations of the rock samples are known. It is expected that more challenges will be encountered in the estimating of the seismic anisotropy parameters from field seismic data. Based on Monte Carlo simulation of vertical transversely isotropic layer cake model using the database of laboratory anisotropy measurement from the literature, we apply the commonly used quartic non-hyperbolic reflection moveout equation to estimate the seismic anisotropy parameters and test its accuracy and sensitivities to the source-receive offset, vertical interval velocity error and time picking error. The testing results show that the methodology works perfectly for noise-free synthetic data with short spread length. However, this method is extremely sensitive to the time picking error caused by mild random noises, and it requires the spread length to be greater than the depth of the reflection event. The uncertainties increase rapidly for the deeper layers and the estimated anisotropy parameters can be very unreliable for a layer with more than five overlain layers. It is possible that an isotropic formation can be misinterpreted as a strong anisotropic formation. The sensitivity analysis should provide useful guidance on how to group the reflection events and build a suitable geological model for anisotropy parameter inversion.

  15. A global sensitivity analysis of crop virtual water content

    Science.gov (United States)

    Tamea, S.; Tuninetti, M.; D'Odorico, P.; Laio, F.; Ridolfi, L.

    2015-12-01

    The concepts of virtual water and water footprint are becoming widely used in the scientific literature and they are proving their usefulness in a number of multidisciplinary contexts. With such growing interest a measure of data reliability (and uncertainty) is becoming pressing but, as of today, assessments of data sensitivity to model parameters, performed at the global scale, are not known. This contribution aims at filling this gap. Starting point of this study is the evaluation of the green and blue virtual water content (VWC) of four staple crops (i.e. wheat, rice, maize, and soybean) at a global high resolution scale. In each grid cell, the crop VWC is given by the ratio between the total crop evapotranspiration over the growing season and the crop actual yield, where evapotranspiration is determined with a detailed daily soil water balance and actual yield is estimated using country-based data, adjusted to account for spatial variability. The model provides estimates of the VWC at a 5x5 arc minutes and it improves on previous works by using the newest available data and including multi-cropping practices in the evaluation. The model is then used as the basis for a sensitivity analysis, in order to evaluate the role of model parameters in affecting the VWC and to understand how uncertainties in input data propagate and impact the VWC accounting. In each cell, small changes are exerted to one parameter at a time, and a sensitivity index is determined as the ratio between the relative change of VWC and the relative change of the input parameter with respect to its reference value. At the global scale, VWC is found to be most sensitive to the planting date, with a positive (direct) or negative (inverse) sensitivity index depending on the typical season of crop planting date. VWC is also markedly dependent on the length of the growing period, with an increase in length always producing an increase of VWC, but with higher spatial variability for rice than for

  16. A radiation analysis of lunar surface habitats

    International Nuclear Information System (INIS)

    De Angelis, G.; Wilson, J.W.; Tripathi, R.K.; Clowdsley, M.S.; Nealy, J.E.

    2003-01-01

    An analysis is performed on the radiation environment found on the surface of the Moon, and applied to different possible lunar base mission scenarios. An optimization technique has been used to minimize the astronaut radiation exposure and at the same time control the effect of shielding, in terms of mass addition and material choice, as a mission cost driver. The optimization process performs minimization of mass along all phases of a mission scenario, considered in terms of time frame, equipment, location, crew characteristics and performance required, radiation exposure annual and career limit constraints (those proposed in NCRP 132), and implementation of the ALARA principle. In the lunar environment manned habitats are to host future crews involved in the construction and/or in the utilization of moon based infrastructure. Three different kinds of lunar missions are considered in the analysis, Moon Base Construction Phase, during which astronauts are on the surface just to build an outpost for future resident crews, Moon Base Outpost Phase, during which astronaut crews are resident but continuing exploration and installation activities, and Moon Base Routine Phase, with shifting resident crews. In each scenario various kinds of habitats, from very simple shelters to more complex bases, are considered in detail (e.g. shape, thickness, materials, etc) with considerations of various shielding strategies. The results for all scenarios clearly showed that the direct exposure to the space environment like in transfers and EVAs phases gives the most of the dose, with the proposed shielded habitats and shelters giving quite a good protection from radiation. Operational constraints on hardware and scenarios have all been considered by the optimization techniques. Within the limits of this preliminary analysis, the three Moon Base related mission scenarios are perfectly feasible from the astronaut radiation safety point of view with the currently adopted and proposed

  17. The clear-sky greenhouse effect sensitivity to a sea surface temperature change

    Science.gov (United States)

    Duvel, J. PH.; Breon, F. M.

    1991-01-01

    The clear-sky greenhouse effect response to a sea surface temperature (SST or Ts) change is studied using outgoing clear-sky longwave radiation measurements from the Earth Radiation Budget Experiment. Considering geographical distributions for July 1987, the relation between the SST, the greenhouse effect (defined as the outgoing infrared flux trapped by atmospheric gases), and the precipitable water vapor content (W), estimated by the Special Sensor Microwave Imager, is analyzed first. A fairly linear relation between W and the normalized greenhouse effect g, is found. On the contrary, the SST dependence of both W and g exhibits nonlinearities with, especially, a large increase for SST above 25 C. This enhanced sensitivity of g and W can be interpreted in part by a corresponding large increase of atmospheric water vapor content related to the transition from subtropical dry regions to equatorial moist regions. Using two years of data (1985 and 1986), the normalized greenhouse effect sensitivity to the sea surface temperature is computed from the interannual variation of monthly mean values.

  18. Surface renewal analysis for estimating turbulent surface fluxes

    International Nuclear Information System (INIS)

    Castellvi, F.

    2009-01-01

    A decade ago, the need for a long-term surface monitoring was recognized to better understand the soil-vegetation-atmosphere scalar exchange and interaction processes. the AmeriFlux concept emerged in the IGBP workshop (La Thuile, IT, 1995). Continuous acquisition of surface fluxes for different species such as temperature, water vapour, CO x , halocarbon, ozone, etc.,) and momentum allows determination of the influence of local (canopy) exchanges, fossil fuel emission, large-scale biotic exchange on ambient concentrations which are crucial to take decisions for protecting natural environments and water resources, to develop new perspective for modern agriculture and forest management and to better understand the global climate change. (Author)

  19. Measurements of skin friction in water using surface stress sensitive films

    International Nuclear Information System (INIS)

    Crafton, J W; Fonov, S D; Jones, E G; Goss, L P; Forlines, R A; Fontaine, A

    2008-01-01

    The measurement of skin friction on hydrodynamic surfaces is of significant value for the design of advanced naval technology, particularly at high Reynolds numbers. Here we report on the development of a new sensor for measurement of skin friction and pressure that operates in both air and water. This sensor is based on an elastic polymer film that deforms under the action of applied normal and tangential loads. Skin friction and pressure gradients are determined by monitoring these deformations and then solving an inverse problem using a finite element model of the elastic film. This technique is known as surface stress sensitive films. In this paper, we describe the development of a sensor package specifically designed for two-dimensional skin friction measurements at a single point. The package has been developed with the goal of making two-dimensional measurements of skin friction in water. Quantitative measurements of skin friction are performed on a high Reynolds number turbulent boundary layer in the 12 inch water tunnel at Penn State University. These skin friction measurements are verified by comparing them to measurements obtained with a drag plate as well as by performing two-dimensional velocity measurements above the sensor using a laser Doppler velocimetry system. The results indicate that the sensor skin friction measurements are accurate to better than 5% and repeatable to better than 2%. The directional sensitivity of the sensor is demonstrated by positioning the sensor at several orientations to the flow. A final interesting feature of this sensor is that it is sensitive to pressure gradients, not to static pressure changes. This feature should prove useful for monitoring the skin friction on a seafaring vessel as the operating depth is changed

  20. Enhanced Sensitivity of Anti-Symmetrically Structured Surface Plasmon Resonance Sensors with Zinc Oxide Intermediate Layers

    Directory of Open Access Journals (Sweden)

    Nan-Fu Chiu

    2013-12-01

    Full Text Available We report a novel design wherein high-refractive-index zinc oxide (ZnO intermediary layers are used in anti-symmetrically structured surface plasmon resonance (SPR devices to enhance signal quality and improve the full width at half maximum (FWHM of the SPR reflectivity curve. The surface plasmon (SP modes of the ZnO intermediary layer were excited by irradiating both sides of the Au film, thus inducing a high electric field at the Au/ZnO interface. We demonstrated that an improvement in the ZnO (002 crystal orientation led to a decrease in the FWHM of the SPR reflectivity curves. We optimized the design of ZnO thin films using different parameters and performed analytical comparisons of the ZnO with conventional chromium (Cr and indium tin oxide (ITO intermediary layers. The present study is based on application of the Fresnel equation, which provides an explanation and verification for the observed narrow SPR reflectivity curve and optical transmittance spectra exhibited by (ZnO/Au, (Cr/Au, and (ITO/Au devices. On exposure to ethanol, the anti-symmetrically structured showed a huge electric field at the Au/ZnO interface and a 2-fold decrease in the FWHM value and a 1.3-fold larger shift in angle interrogation and a 4.5-fold high-sensitivity shift in intensity interrogation. The anti-symmetrically structured of ZnO intermediate layers exhibited a wider linearity range and much higher sensitivity. It also exhibited a good linear relationship between the incident angle and ethanol concentration in the tested range. Thus, we demonstrated a novel and simple method for fabricating high-sensitivity, high-resolution SPR biosensors that provide high accuracy and precision over relevant ranges of analyte measurement.

  1. Sensitivity of Distributions of Climate System Properties to Surface Temperature Datasets

    Science.gov (United States)

    Libardoni, A. G.; Forest, C. E.

    2011-12-01

    Predictions of climate change from models depend strongly on the representation of climate system properties emerging from the processes and feedbacks in the models. The quality of any model prediction can be evaluated by determining how well its output reproduces the observed climate system. With this evaluation, the reliability of climate projections derived from the model and provided for policy makers is assessed and quantified. In this study, surface temperature, upper-air temperature, and ocean heat content data are used to constrain the distributions of the parameters that define three climate system properties in the MIT Integrated Global Systems Model: climate sensitivity, the rate of ocean heat uptake into the deep ocean, and net anthropogenic aerosol forcing. In particular, we explore the sensitivity of the distributions to the surface temperature dataset used to estimate the likelihood of model output given the observed climate records. In total, five different reconstructions of past surface temperatures are used and the resulting parameter distribution functions differ from each other. Differences in estimates of climate sensitivity mode and mean are as great as 1 K between the datasets, with an overall range of 1.2 to 5.3 K using the 5-95 confidence intervals. Ocean effective diffusivity is poorly constrained regardless of which dataset is used. All distributions show broad distributions and only three show signs of a distribution mode. When a mode is present, they tend to be for low diffusivity values. Distributions for the net aerosol forcing show similar shapes and cluster into two groups that are shifted by approximately 0.1 watts per square meter. However, the overall spread of forcing values from the 5-95 confidence interval, -0.19 to -0.83 watts per square meter, is small compared to other uncertainties in climate forcings. Transient climate response estimates derived from these distributions range between 0.87 and 2.41 K. Similar to the

  2. Deterministic sensitivity and uncertainty analysis for large-scale computer models

    International Nuclear Information System (INIS)

    Worley, B.A.; Pin, F.G.; Oblow, E.M.; Maerker, R.E.; Horwedel, J.E.; Wright, R.Q.

    1988-01-01

    The fields of sensitivity and uncertainty analysis have traditionally been dominated by statistical techniques when large-scale modeling codes are being analyzed. These methods are able to estimate sensitivities, generate response surfaces, and estimate response probability distributions given the input parameter probability distributions. Because the statistical methods are computationally costly, they are usually applied only to problems with relatively small parameter sets. Deterministic methods, on the other hand, are very efficient and can handle large data sets, but generally require simpler models because of the considerable programming effort required for their implementation. The first part of this paper reports on the development and availability of two systems, GRESS and ADGEN, that make use of computer calculus compilers to automate the implementation of deterministic sensitivity analysis capability into existing computer models. This automation removes the traditional limitation of deterministic sensitivity methods. This second part of the paper describes a deterministic uncertainty analysis method (DUA) that uses derivative information as a basis to propagate parameter probability distributions to obtain result probability distributions. This paper is applicable to low-level radioactive waste disposal system performance assessment

  3. Variance-based sensitivity analysis for wastewater treatment plant modelling.

    Science.gov (United States)

    Cosenza, Alida; Mannina, Giorgio; Vanrolleghem, Peter A; Neumann, Marc B

    2014-02-01

    Global sensitivity analysis (GSA) is a valuable tool to support the use of mathematical models that characterise technical or natural systems. In the field of wastewater modelling, most of the recent applications of GSA use either regression-based methods, which require close to linear relationships between the model outputs and model factors, or screening methods, which only yield qualitative results. However, due to the characteristics of membrane bioreactors (MBR) (non-linear kinetics, complexity, etc.) there is an interest to adequately quantify the effects of non-linearity and interactions. This can be achieved with variance-based sensitivity analysis methods. In this paper, the Extended Fourier Amplitude Sensitivity Testing (Extended-FAST) method is applied to an integrated activated sludge model (ASM2d) for an MBR system including microbial product formation and physical separation processes. Twenty-one model outputs located throughout the different sections of the bioreactor and 79 model factors are considered. Significant interactions among the model factors are found. Contrary to previous GSA studies for ASM models, we find the relationship between variables and factors to be non-linear and non-additive. By analysing the pattern of the variance decomposition along the plant, the model factors having the highest variance contributions were identified. This study demonstrates the usefulness of variance-based methods in membrane bioreactor modelling where, due to the presence of membranes and different operating conditions than those typically found in conventional activated sludge systems, several highly non-linear effects are present. Further, the obtained results highlight the relevant role played by the modelling approach for MBR taking into account simultaneously biological and physical processes. © 2013.

  4. DDASAC, Double-Precision Differential or Algebraic Sensitivity Analysis

    International Nuclear Information System (INIS)

    Caracotsios, M.; Stewart, W.E.; Petzold, L.

    1997-01-01

    1 - Description of program or function: DDASAC solves nonlinear initial-value problems involving stiff implicit systems of ordinary differential and algebraic equations. Purely algebraic nonlinear systems can also be solved, given an initial guess within the region of attraction of a solution. Options include automatic reconciliation of inconsistent initial states and derivatives, automatic initial step selection, direct concurrent parametric sensitivity analysis, and stopping at a prescribed value of any user-defined functional of the current solution vector. Local error control (in the max-norm or the 2-norm) is provided for the state vector and can include the sensitivities on request. 2 - Method of solution: Reconciliation of initial conditions is done with a damped Newton algorithm adapted from Bain and Stewart (1991). Initial step selection is done by the first-order algorithm of Shampine (1987), extended here to differential-algebraic equation systems. The solution is continued with the DASSL predictor- corrector algorithm (Petzold 1983, Brenan et al. 1989) with the initial acceleration phase detected and with row scaling of the Jacobian added. The backward-difference formulas for the predictor and corrector are expressed in divide-difference form, and the fixed-leading-coefficient form of the corrector (Jackson and Sacks-Davis 1980, Brenan et al. 1989) is used. Weights for error tests are updated in each step with the user's tolerances at the predicted state. Sensitivity analysis is performed directly on the corrector equations as given by Catacotsios and Stewart (1985) and is extended here to the initialization when needed. 3 - Restrictions on the complexity of the problem: This algorithm, like DASSL, performs well on differential-algebraic systems of index 0 and 1 but not on higher-index systems; see Brenan et al. (1989). The user assigns the work array lengths and the output unit. The machine number range and precision are determined at run time by a

  5. Uncertainty and sensitivity analysis of environmental transport models

    International Nuclear Information System (INIS)

    Margulies, T.S.; Lancaster, L.E.

    1985-01-01

    An uncertainty and sensitivity analysis has been made of the CRAC-2 (Calculations of Reactor Accident Consequences) atmospheric transport and deposition models. Robustness and uncertainty aspects of air and ground deposited material and the relative contribution of input and model parameters were systematically studied. The underlying data structures were investigated using a multiway layout of factors over specified ranges generated via a Latin hypercube sampling scheme. The variables selected in our analysis include: weather bin, dry deposition velocity, rain washout coefficient/rain intensity, duration of release, heat content, sigma-z (vertical) plume dispersion parameter, sigma-y (crosswind) plume dispersion parameter, and mixing height. To determine the contributors to the output variability (versus distance from the site) step-wise regression analyses were performed on transformations of the spatial concentration patterns simulated. 27 references, 2 figures, 3 tables

  6. Modelling pesticides volatilisation in greenhouses: Sensitivity analysis of a modified PEARL model.

    Science.gov (United States)

    Houbraken, Michael; Doan Ngoc, Kim; van den Berg, Frederik; Spanoghe, Pieter

    2017-12-01

    The application of the existing PEARL model was extended to include estimations of the concentration of crop protection products in greenhouse (indoor) air due to volatilisation from the plant surface. The model was modified to include the processes of ventilation of the greenhouse air to the outside atmosphere and transformation in the air. A sensitivity analysis of the model was performed by varying selected input parameters on a one-by-one basis and comparing the model outputs with the outputs of the reference scenarios. The sensitivity analysis indicates that - in addition to vapour pressure - the model had the highest ratio of variation for the rate ventilation rate and thickness of the boundary layer on the day of application. On the days after application, competing processes, degradation and uptake in the plant, becomes more important. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Validation and sensitivity tests on improved parametrizations of a land surface process model (LSPM) in the Po Valley

    International Nuclear Information System (INIS)

    Cassardo, C.; Carena, E.; Longhetto, A.

    1998-01-01

    The Land Surface Process Model (LSPM) has been improved with respect to the 1. version of 1994. The modifications have involved the parametrizations of the radiation terms and of turbulent heat fluxes. A parametrization of runoff has also been developed, in order to close the hydrologic balance. This 2. version of LSPM has been validated against experimental data gathered at Mottarone (Verbania, Northern Italy) during a field experiment. The results of this validation show that this new version is able to apportionate the energy into sensible and latent heat fluxes. LSPM has also been submitted to a series of sensitivity tests in order to investigate the hydrological part of the model. The physical quantities selected in these sensitivity experiments have been the initial soil moisture content and the rainfall intensity. In each experiment, the model has been forced by using the observations carried out at the synoptic stations of San Pietro Capofiume (Po Valley, Italy). The observed characteristics of soil and vegetation (not involved in the sensitivity tests) have been used as initial and boundary conditions. The results of the simulation show that LSPM can reproduce well the energy, heat and water budgets and their behaviours with varying the selected parameters. A careful analysis of the LSPM output shows also the importance to identify the effective soil type

  8. Surface Acoustic Wave Nebulisation Mass Spectrometry for the Fast and Highly Sensitive Characterisation of Synthetic Dyes in Textile Samples

    Science.gov (United States)

    Astefanei, Alina; van Bommel, Maarten; Corthals, Garry L.

    2017-10-01

    Surface acoustic wave nebulisation (SAWN) mass spectrometry (MS) is a method to generate gaseous ions compatible with direct MS of minute samples at femtomole sensitivity. To perform SAWN, acoustic waves are propagated through a LiNbO3 sampling chip, and are conducted to the liquid sample, which ultimately leads to the generation of a fine mist containing droplets of nanometre to micrometre diameter. Through fission and evaporation, the droplets undergo a phase change from liquid to gaseous analyte ions in a non-destructive manner. We have developed SAWN technology for the characterisation of organic colourants in textiles. It generates electrospray-ionisation-like ions in a non-destructive manner during ionisation, as can be observed by the unmodified chemical structure. The sample size is decreased by tenfold to 1000-fold when compared with currently used liquid chromatography-MS methods, with equal or better sensitivity. This work underscores SAWN-MS as an ideal tool for molecular analysis of art objects as it is non-destructive, is rapid, involves minimally invasive sampling and is more sensitive than current MS-based methods. [Figure not available: see fulltext.

  9. Cross-covariance based global dynamic sensitivity analysis

    Science.gov (United States)

    Shi, Yan; Lu, Zhenzhou; Li, Zhao; Wu, Mengmeng

    2018-02-01

    For identifying the cross-covariance source of dynamic output at each time instant for structural system involving both input random variables and stochastic processes, a global dynamic sensitivity (GDS) technique is proposed. The GDS considers the effect of time history inputs on the dynamic output. In the GDS, the cross-covariance decomposition is firstly developed to measure the contribution of the inputs to the output at different time instant, and an integration of the cross-covariance change over the specific time interval is employed to measure the whole contribution of the input to the cross-covariance of output. Then, the GDS main effect indices and the GDS total effect indices can be easily defined after the integration, and they are effective in identifying the important inputs and the non-influential inputs on the cross-covariance of output at each time instant, respectively. The established GDS analysis model has the same form with the classical ANOVA when it degenerates to the static case. After degeneration, the first order partial effect can reflect the individual effects of inputs to the output variance, and the second order partial effect can reflect the interaction effects to the output variance, which illustrates the consistency of the proposed GDS indices and the classical variance-based sensitivity indices. The MCS procedure and the Kriging surrogate method are developed to solve the proposed GDS indices. Several examples are introduced to illustrate the significance of the proposed GDS analysis technique and the effectiveness of the proposed solution.

  10. Complex finite element sensitivity method for creep analysis

    International Nuclear Information System (INIS)

    Gomez-Farias, Armando; Montoya, Arturo; Millwater, Harry

    2015-01-01

    The complex finite element method (ZFEM) has been extended to perform sensitivity analysis for mechanical and structural systems undergoing creep deformation. ZFEM uses a complex finite element formulation to provide shape, material, and loading derivatives of the system response, providing an insight into the essential factors which control the behavior of the system as a function of time. A complex variable-based quadrilateral user element (UEL) subroutine implementing the power law creep constitutive formulation was incorporated within the Abaqus commercial finite element software. The results of the complex finite element computations were verified by comparing them to the reference solution for the steady-state creep problem of a thick-walled cylinder in the power law creep range. A practical application of the ZFEM implementation to creep deformation analysis is the calculation of the skeletal point of a notched bar test from a single ZFEM run. In contrast, the standard finite element procedure requires multiple runs. The value of the skeletal point is that it identifies the location where the stress state is accurate, regardless of the certainty of the creep material properties. - Highlights: • A novel finite element sensitivity method (ZFEM) for creep was introduced. • ZFEM has the capability to calculate accurate partial derivatives. • ZFEM can be used for identification of the skeletal point of creep structures. • ZFEM can be easily implemented in a commercial software, e.g. Abaqus. • ZFEM results were shown to be in excellent agreement with analytical solutions

  11. Overview of hybrid subspace methods for uncertainty quantification, sensitivity analysis

    International Nuclear Information System (INIS)

    Abdel-Khalik, Hany S.; Bang, Youngsuk; Wang, Congjian

    2013-01-01

    Highlights: ► We overview the state-of-the-art in uncertainty quantification and sensitivity analysis. ► We overview new developments in above areas using hybrid methods. ► We give a tutorial introduction to above areas and the new developments. ► Hybrid methods address the explosion in dimensionality in nonlinear models. ► Representative numerical experiments are given. -- Abstract: The role of modeling and simulation has been heavily promoted in recent years to improve understanding of complex engineering systems. To realize the benefits of modeling and simulation, concerted efforts in the areas of uncertainty quantification and sensitivity analysis are required. The manuscript intends to serve as a pedagogical presentation of the material to young researchers and practitioners with little background on the subjects. We believe this is important as the role of these subjects is expected to be integral to the design, safety, and operation of existing as well as next generation reactors. In addition to covering the basics, an overview of the current state-of-the-art will be given with particular emphasis on the challenges pertaining to nuclear reactor modeling. The second objective will focus on presenting our own development of hybrid subspace methods intended to address the explosion in the computational overhead required when handling real-world complex engineering systems.

  12. Control strategies and sensitivity analysis of anthroponotic visceral leishmaniasis model.

    Science.gov (United States)

    Zamir, Muhammad; Zaman, Gul; Alshomrani, Ali Saleh

    2017-12-01

    This study proposes a mathematical model of Anthroponotic visceral leishmaniasis epidemic with saturated infection rate and recommends different control strategies to manage the spread of this disease in the community. To do this, first, a model formulation is presented to support these strategies, with quantifications of transmission and intervention parameters. To understand the nature of the initial transmission of the disease, the reproduction number [Formula: see text] is obtained by using the next-generation method. On the basis of sensitivity analysis of the reproduction number [Formula: see text], four different control strategies are proposed for managing disease transmission. For quantification of the prevalence period of the disease, a numerical simulation for each strategy is performed and a detailed summary is presented. Disease-free state is obtained with the help of control strategies. The threshold condition for globally asymptotic stability of the disease-free state is found, and it is ascertained that the state is globally stable. On the basis of sensitivity analysis of the reproduction number, it is shown that the disease can be eradicated by using the proposed strategies.

  13. Sensitivity Analysis in Observational Research: Introducing the E-Value.

    Science.gov (United States)

    VanderWeele, Tyler J; Ding, Peng

    2017-08-15

    Sensitivity analysis is useful in assessing how robust an association is to potential unmeasured or uncontrolled confounding. This article introduces a new measure called the "E-value," which is related to the evidence for causality in observational studies that are potentially subject to confounding. The E-value is defined as the minimum strength of association, on the risk ratio scale, that an unmeasured confounder would need to have with both the treatment and the outcome to fully explain away a specific treatment-outcome association, conditional on the measured covariates. A large E-value implies that considerable unmeasured confounding would be needed to explain away an effect estimate. A small E-value implies little unmeasured confounding would be needed to explain away an effect estimate. The authors propose that in all observational studies intended to produce evidence for causality, the E-value be reported or some other sensitivity analysis be used. They suggest calculating the E-value for both the observed association estimate (after adjustments for measured confounders) and the limit of the confidence interval closest to the null. If this were to become standard practice, the ability of the scientific community to assess evidence from observational studies would improve considerably, and ultimately, science would be strengthened.

  14. Nordic reference study on uncertainty and sensitivity analysis

    International Nuclear Information System (INIS)

    Hirschberg, S.; Jacobsson, P.; Pulkkinen, U.; Porn, K.

    1989-01-01

    This paper provides a review of the first phase of Nordic reference study on uncertainty and sensitivity analysis. The main objective of this study is to use experiences form previous Nordic Benchmark Exercises and reference studies concerning critical modeling issues such as common cause failures and human interactions, and to demonstrate the impact of associated uncertainties on the uncertainty of the investigated accident sequence. This has been done independently by three working groups which used different approaches to modeling and to uncertainty analysis. The estimated uncertainty interval for the analyzed accident sequence is large. Also the discrepancies between the groups are substantial but can be explained. Sensitivity analyses which have been carried out concern e.g. use of different CCF-quantification models, alternative handling of CCF-data, time windows for operator actions and time dependences in phase mission operation, impact of state-of-knowledge dependences and ranking of dominating uncertainty contributors. Specific findings with respect to these issues are summarized in the paper

  15. Simple Sensitivity Analysis for Orion Guidance Navigation and Control

    Science.gov (United States)

    Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar

    2013-01-01

    The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch. We describe in this paper a sensitivity analysis tool ("Critical Factors Tool" or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.

  16. Deterministic sensitivity analysis for the numerical simulation of contaminants transport

    International Nuclear Information System (INIS)

    Marchand, E.

    2007-12-01

    The questions of safety and uncertainty are central to feasibility studies for an underground nuclear waste storage site, in particular the evaluation of uncertainties about safety indicators which are due to uncertainties concerning properties of the subsoil or of the contaminants. The global approach through probabilistic Monte Carlo methods gives good results, but it requires a large number of simulations. The deterministic method investigated here is complementary. Based on the Singular Value Decomposition of the derivative of the model, it gives only local information, but it is much less demanding in computing time. The flow model follows Darcy's law and the transport of radionuclides around the storage site follows a linear convection-diffusion equation. Manual and automatic differentiation are compared for these models using direct and adjoint modes. A comparative study of both probabilistic and deterministic approaches for the sensitivity analysis of fluxes of contaminants through outlet channels with respect to variations of input parameters is carried out with realistic data provided by ANDRA. Generic tools for sensitivity analysis and code coupling are developed in the Caml language. The user of these generic platforms has only to provide the specific part of the application in any language of his choice. We also present a study about two-phase air/water partially saturated flows in hydrogeology concerning the limitations of the Richards approximation and of the global pressure formulation used in petroleum engineering. (author)

  17. Sensitivity Analysis of a Riparian Vegetation Growth Model

    Directory of Open Access Journals (Sweden)

    Michael Nones

    2016-11-01

    Full Text Available The paper presents a sensitivity analysis of two main parameters used in a mathematic model able to evaluate the effects of changing hydrology on the growth of riparian vegetation along rivers and its effects on the cross-section width. Due to a lack of data in existing literature, in a past study the schematization proposed here was applied only to two large rivers, assuming steady conditions for the vegetational carrying capacity and coupling the vegetal model with a 1D description of the river morphology. In this paper, the limitation set by steady conditions is overcome, imposing the vegetational evolution dependent upon the initial plant population and the growth rate, which represents the potential growth of the overall vegetation along the watercourse. The sensitivity analysis shows that, regardless of the initial population density, the growth rate can be considered the main parameter defining the development of riparian vegetation, but it results site-specific effects, with significant differences for large and small rivers. Despite the numerous simplifications adopted and the small database analyzed, the comparison between measured and computed river widths shows a quite good capability of the model in representing the typical interactions between riparian vegetation and water flow occurring along watercourses. After a thorough calibration, the relatively simple structure of the code permits further developments and applications to a wide range of alluvial rivers.

  18. Sensitivity analysis of numerical model of prestressed concrete containment

    Energy Technology Data Exchange (ETDEWEB)

    Bílý, Petr, E-mail: petr.bily@fsv.cvut.cz; Kohoutková, Alena, E-mail: akohout@fsv.cvut.cz

    2015-12-15

    Graphical abstract: - Highlights: • FEM model of prestressed concrete containment with steel liner was created. • Sensitivity analysis of changes in geometry and loads was conducted. • Steel liner and temperature effects are the most important factors. • Creep and shrinkage parameters are essential for the long time analysis. • Prestressing schedule is a key factor in the early stages. - Abstract: Safety is always the main consideration in the design of containment of nuclear power plant. However, efficiency of the design process should be also taken into consideration. Despite the advances in computational abilities in recent years, simplified analyses may be found useful for preliminary scoping or trade studies. In the paper, a study on sensitivity of finite element model of prestressed concrete containment to changes in geometry, loads and other factors is presented. Importance of steel liner, reinforcement, prestressing process, temperature changes, nonlinearity of materials as well as density of finite elements mesh is assessed in the main stages of life cycle of the containment. Although the modeling adjustments have not produced any significant changes in computation time, it was found that in some cases simplified modeling process can lead to significant reduction of work time without degradation of the results.

  19. Global sensitivity analysis for models with spatially dependent outputs

    International Nuclear Information System (INIS)

    Iooss, B.; Marrel, A.; Jullien, M.; Laurent, B.

    2011-01-01

    The global sensitivity analysis of a complex numerical model often calls for the estimation of variance-based importance measures, named Sobol' indices. Meta-model-based techniques have been developed in order to replace the CPU time-expensive computer code with an inexpensive mathematical function, which predicts the computer code output. The common meta-model-based sensitivity analysis methods are well suited for computer codes with scalar outputs. However, in the environmental domain, as in many areas of application, the numerical model outputs are often spatial maps, which may also vary with time. In this paper, we introduce an innovative method to obtain a spatial map of Sobol' indices with a minimal number of numerical model computations. It is based upon the functional decomposition of the spatial output onto a wavelet basis and the meta-modeling of the wavelet coefficients by the Gaussian process. An analytical example is presented to clarify the various steps of our methodology. This technique is then applied to a real hydrogeological case: for each model input variable, a spatial map of Sobol' indices is thus obtained. (authors)

  20. Multivariate Sensitivity Analysis of Time-of-Flight Sensor Fusion

    Science.gov (United States)

    Schwarz, Sebastian; Sjöström, Mårten; Olsson, Roger

    2014-09-01

    Obtaining three-dimensional scenery data is an essential task in computer vision, with diverse applications in various areas such as manufacturing and quality control, security and surveillance, or user interaction and entertainment. Dedicated Time-of-Flight sensors can provide detailed scenery depth in real-time and overcome short-comings of traditional stereo analysis. Nonetheless, they do not provide texture information and have limited spatial resolution. Therefore such sensors are typically combined with high resolution video sensors. Time-of-Flight Sensor Fusion is a highly active field of research. Over the recent years, there have been multiple proposals addressing important topics such as texture-guided depth upsampling and depth data denoising. In this article we take a step back and look at the underlying principles of ToF sensor fusion. We derive the ToF sensor fusion error model and evaluate its sensitivity to inaccuracies in camera calibration and depth measurements. In accordance with our findings, we propose certain courses of action to ensure high quality fusion results. With this multivariate sensitivity analysis of the ToF sensor fusion model, we provide an important guideline for designing, calibrating and running a sophisticated Time-of-Flight sensor fusion capture systems.

  1. Hydrocoin level 3 - Testing methods for sensitivity/uncertainty analysis

    International Nuclear Information System (INIS)

    Grundfelt, B.; Lindbom, B.; Larsson, A.; Andersson, K.

    1991-01-01

    The HYDROCOIN study is an international cooperative project for testing groundwater hydrology modelling strategies for performance assessment of nuclear waste disposal. The study was initiated in 1984 by the Swedish Nuclear Power Inspectorate and the technical work was finalised in 1987. The participating organisations are regulatory authorities as well as implementing organisations in 10 countries. The study has been performed at three levels aimed at studying computer code verification, model validation and sensitivity/uncertainty analysis respectively. The results from the first two levels, code verification and model validation, have been published in reports in 1988 and 1990 respectively. This paper focuses on some aspects of the results from Level 3, sensitivity/uncertainty analysis, for which a final report is planned to be published during 1990. For Level 3, seven test cases were defined. Some of these aimed at exploring the uncertainty associated with the modelling results by simply varying parameter values and conceptual assumptions. In other test cases statistical sampling methods were applied. One of the test cases dealt with particle tracking and the uncertainty introduced by this type of post processing. The amount of results available is substantial although unevenly spread over the test cases. It has not been possible to cover all aspects of the results in this paper. Instead, the different methods applied will be illustrated by some typical analyses. 4 figs., 9 refs

  2. Estimation and analysis of the sensitivity of monoenergetic electron radiography of composite materials with fluctuating composition

    International Nuclear Information System (INIS)

    Rudenko, V.N.; Yunda, N.T.

    1978-01-01

    A sensitivity analysis of the electron defectoscopy method for composite materials with fluctuating composition has been carried out. Quantitative evaluations of the testing sensitivity depending on inspection conditions have been obtained, and calculations of the instrumental error are shown. Based on numerical calculations, a comparison of error has been carried out between high-energy electron and X-ray testings. It is shown that when testing composite materials with a surface density of up to 7-10 g/cm 2 , the advantage of the electron defectoscopy method as compared to the X-ray one is the higher sensitivity and lower instrumental error. The advantage of the electron defectoscopy method over the X-ray one as regards the sensitivity is greater when a light-atom component is predomenant in the composition. A monoenergetic electron beam from a betatron with an energy of up to 30 MeV should be used for testing materials with a surface density of up to 15 g/cm 2

  3. Thermodynamics-based Metabolite Sensitivity Analysis in metabolic networks.

    Science.gov (United States)

    Kiparissides, A; Hatzimanikatis, V

    2017-01-01

    The increasing availability of large metabolomics datasets enhances the need for computational methodologies that can organize the data in a way that can lead to the inference of meaningful relationships. Knowledge of the metabolic state of a cell and how it responds to various stimuli and extracellular conditions can offer significant insight in the regulatory functions and how to manipulate them. Constraint based methods, such as Flux Balance Analysis (FBA) and Thermodynamics-based flux analysis (TFA), are commonly used to estimate the flow of metabolites through genome-wide metabolic networks, making it possible to identify the ranges of flux values that are consistent with the studied physiological and thermodynamic conditions. However, unless key intracellular fluxes and metabolite concentrations are known, constraint-based models lead to underdetermined problem formulations. This lack of information propagates as uncertainty in the estimation of fluxes and basic reaction properties such as the determination of reaction directionalities. Therefore, knowledge of which metabolites, if measured, would contribute the most to reducing this uncertainty can significantly improve our ability to define the internal state of the cell. In the present work we combine constraint based modeling, Design of Experiments (DoE) and Global Sensitivity Analysis (GSA) into the Thermodynamics-based Metabolite Sensitivity Analysis (TMSA) method. TMSA ranks metabolites comprising a metabolic network based on their ability to constrain the gamut of possible solutions to a limited, thermodynamically consistent set of internal states. TMSA is modular and can be applied to a single reaction, a metabolic pathway or an entire metabolic network. This is, to our knowledge, the first attempt to use metabolic modeling in order to provide a significance ranking of metabolites to guide experimental measurements. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier

  4. Sensitivity analysis for hydrology and pesticide supply towards the river in SWAT

    Science.gov (United States)

    Holvoet, K.; van Griensven, A.; Seuntjens, P.; Vanrolleghem, P. A.

    The dynamic behaviour of pesticides in river systems strongly depends on varying climatological conditions and agricultural management practices. To describe this behaviour at the river-basin scale, integrated hydrological and water quality models are needed. A crucial step in understanding the various processes determining pesticide fate is to perform a sensitivity analysis. Sensitivity analysis for hydrology and pesticide supply in SWAT (Soil and Water Assessment Tool) will provide useful support for the development of a reliable hydrological model and will give insight in which parameters are most sensitive concerning pesticide supply towards rivers. The study was performed on the Nil catchment in Belgium. In this study we utilised an LH-OAT sensitivity analysis. The LH-OAT method combines the One-factor-At-a-Time (OAT) design and Latin Hypercube (LH) sampling by taking the Latin Hypercube samples as initial points for an OAT design. By means of the LH-OAT sensitivity analysis, the dominant hydrological parameters were determined and a reduction of the number of model parameters was performed. Dominant hydrological parameters were the curve number (CN2), the surface runoff lag (surlag), the recharge to deep aquifer (rchrg_dp) and the threshold depth of water in the shallow aquifer (GWQMN). Next, the selected parameters were estimated by manual calibration. Hereby, the Nash-Sutcliffe coefficient of efficiency improved from an initial value of -22.4 to +0.53. In the second part, sensitivity analyses were performed to provide insight in which parameters or model inputs contribute most to variance in pesticide output. The results of this study show that for the Nil catchment, hydrologic parameters are dominant in controlling pesticide predictions. The other parameter that affects pesticide concentrations in surface water is ‘apfp_pest’, which meaning was changed into a parameter that controls direct losses to the river system (e.g., through the clean up of spray

  5. Surface and interface analysis an electrochemists toolbox

    CERN Document Server

    Holze, Rudolf

    2009-01-01

    A broad, almost encyclopedic overview of spectroscopic and other analytical techniques useful for investigations of phase boundaries in electrochemistry is presented. The analysis of electrochemical interfaces and interphases on a microscopic, even molecular level, is of central importance for an improved understanding of the structure and dynamics of these phase boundaries. The gained knowledge will be needed for improvements of methods and applications reaching from electrocatalysis, electrochemical energy conversion, biocompatibility of metals, corrosion protection to galvanic surface treatment and finishing. The book provides an overview as complete as possible and enables the reader to choose methods most suitable for tackling his particular task. It is nevertheless compact and does not flood the reader with the details of review papers.

  6. Surface Management System Departure Event Data Analysis

    Science.gov (United States)

    Monroe, Gilena A.

    2010-01-01

    This paper presents a data analysis of the Surface Management System (SMS) performance of departure events, including push-back and runway departure events.The paper focuses on the detection performance, or the ability to detect departure events, as well as the prediction performance of SMS. The results detail a modest overall detection performance of push-back events and a significantly high overall detection performance of runway departure events. The overall detection performance of SMS for push-back events is approximately 55%.The overall detection performance of SMS for runway departure events nears 100%. This paper also presents the overall SMS prediction performance for runway departure events as well as the timeliness of the Aircraft Situation Display for Industry data source for SMS predictions.

  7. Dynamic sensitivity analysis of long running landslide models through basis set expansion and meta-modelling

    Science.gov (United States)

    Rohmer, Jeremy

    2016-04-01

    Predicting the temporal evolution of landslides is typically supported by numerical modelling. Dynamic sensitivity analysis aims at assessing the influence of the landslide properties on the time-dependent predictions (e.g., time series of landslide displacements). Yet two major difficulties arise: 1. Global sensitivity analysis require running the landslide model a high number of times (> 1000), which may become impracticable when the landslide model has a high computation time cost (> several hours); 2. Landslide model outputs are not scalar, but function of time, i.e. they are n-dimensional vectors with n usually ranging from 100 to 1000. In this article, I explore the use of a basis set expansion, such as principal component analysis, to reduce the output dimensionality to a few components, each of them being interpreted as a dominant mode of variation in the overall structure of the temporal evolution. The computationally intensive calculation of the Sobol' indices for each of these components are then achieved through meta-modelling, i.e. by replacing the landslide model by a "costless-to-evaluate" approximation (e.g., a projection pursuit regression model). The methodology combining "basis set expansion - meta-model - Sobol' indices" is then applied to the La Frasse landslide to investigate the dynamic sensitivity analysis of the surface horizontal displacements to the slip surface properties during the pore pressure changes. I show how to extract information on the sensitivity of each main modes of temporal behaviour using a limited number (a few tens) of long running simulations. In particular, I identify the parameters, which trigger the occurrence of a turning point marking a shift between a regime of low values of landslide displacements and one of high values.

  8. Assessing parameter importance of the Common Land Model based on qualitative and quantitative sensitivity analysis

    Directory of Open Access Journals (Sweden)

    J. Li

    2013-08-01

    Full Text Available Proper specification of model parameters is critical to the performance of land surface models (LSMs. Due to high dimensionality and parameter interaction, estimating parameters of an LSM is a challenging task. Sensitivity analysis (SA is a tool that can screen out the most influential parameters on model outputs. In this study, we conducted parameter screening for six output fluxes for the Common Land Model: sensible heat, latent heat, upward longwave radiation, net radiation, soil temperature and soil moisture. A total of 40 adjustable parameters were considered. Five qualitative SA methods, including local, sum-of-trees, multivariate adaptive regression splines, delta test and Morris methods, were compared. The proper sampling design and sufficient sample size necessary to effectively screen out the sensitive parameters were examined. We found that there are 2–8 sensitive parameters, depending on the output type, and about 400 samples are adequate to reliably identify the most sensitive parameters. We also employed a revised Sobol' sensitivity method to quantify the importance of all parameters. The total effects of the parameters were used to assess the contribution of each parameter to the total variances of the model outputs. The results confirmed that global SA methods can generally identify the most sensitive parameters effectively, while local SA methods result in type I errors (i.e., sensitive parameters labeled as insensitive or type II errors (i.e., insensitive parameters labeled as sensitive. Finally, we evaluated and confirmed the screening results for their consistency with the physical interpretation of the model parameters.

  9. Sensitivity analysis for modules for various biosphere types

    International Nuclear Information System (INIS)

    Karlsson, Sara; Bergstroem, U.; Rosen, K.

    2000-09-01

    This study presents the results of a sensitivity analysis for the modules developed earlier for calculation of ecosystem specific dose conversion factors (EDFs). The report also includes a comparison between the probabilistically calculated mean values of the EDFs and values gained in deterministic calculations. An overview of the distribution of radionuclides between different environmental parts in the models is also presented. The radionuclides included in the study were 36 Cl, 59 Ni, 93 Mo, 129 I, 135 Cs, 237 Np and 239 Pu, sel to represent various behaviour in the biosphere and some are of particular importance from the dose point of view. The deterministic and probabilistic EDFs showed a good agreement, for most nuclides and modules. Exceptions from this occurred if very skew distributions were used for parameters of importance for the results. Only a minor amount of the released radionuclides were present in the model compartments for all modules, except for the agricultural land module. The differences between the radionuclides were not pronounced which indicates that nuclide specific parameters were of minor importance for the retention of radionuclides for the simulated time period of 10 000 years in those modules. The results from the agricultural land module showed a different pattern. Large amounts of the radionuclides were present in the solid fraction of the saturated soil zone. The high retention within this compartment makes the zone a potential source for future exposure. Differences between the nuclides due to element specific Kd-values could be seen. The amount of radionuclides present in the upper soil layer, which is the most critical zone for exposure to humans, was less then 1% for all studied radionuclides. The sensitivity analysis showed that the physical/chemical parameters were the most important in most modules in contrast to the dominance of biological parameters in the uncertainty analysis. The only exception was the well module where

  10. Sensitivity analysis of the terrestrial food chain model FOOD III

    International Nuclear Information System (INIS)

    Zach, Reto.

    1980-10-01

    As a first step in constructing a terrestrial food chain model suitable for long-term waste management situations, a numerical sensitivity analysis of FOOD III was carried out to identify important model parameters. The analysis involved 42 radionuclides, four pathways, 14 food types, 93 parameters and three percentages of parameter variation. We also investigated the importance of radionuclides, pathways and food types. The analysis involved a simple contamination model to render results from individual pathways comparable. The analysis showed that radionuclides vary greatly in their dose contribution to each of the four pathways, but relative contributions to each pathway are very similar. Man's and animals' drinking water pathways are much more important than the leaf and root pathways. However, this result depends on the contamination model used. All the pathways contain unimportant food types. Considering the number of parameters involved, FOOD III has too many different food types. Many of the parameters of the leaf and root pathway are important. However, this is true for only a few of the parameters of animals' drinking water pathway, and for neither of the two parameters of mans' drinking water pathway. The radiological decay constant increases the variability of these results. The dose factor is consistently the most important variable, and it explains most of the variability of radionuclide doses within pathways. Consideration of the variability of dose factors is important in contemporary as well as long-term waste management assessment models, if realistic estimates are to be made. (auth)

  11. Uncertainty and sensitivity analysis in nuclear accident consequence assessment

    International Nuclear Information System (INIS)

    Karlberg, Olof.

    1989-01-01

    This report contains the results of a four year project in research contracts with the Nordic Cooperation in Nuclear Safety and the National Institute for Radiation Protection. An uncertainty/sensitivity analysis methodology consisting of Latin Hypercube sampling and regression analysis was applied to an accident consequence model. A number of input parameters were selected and the uncertainties related to these parameter were estimated within a Nordic group of experts. Individual doses, collective dose, health effects and their related uncertainties were then calculated for three release scenarios and for a representative sample of meteorological situations. From two of the scenarios the acute phase after an accident were simulated and from one the long time consequences. The most significant parameters were identified. The outer limits of the calculated uncertainty distributions are large and will grow to several order of magnitudes for the low probability consequences. The uncertainty in the expectation values are typical a factor 2-5 (1 Sigma). The variation in the model responses due to the variation of the weather parameters is fairly equal to the parameter uncertainty induced variation. The most important parameters showed out to be different for each pathway of exposure, which could be expected. However, the overall most important parameters are the wet deposition coefficient and the shielding factors. A general discussion of the usefulness of uncertainty analysis in consequence analysis is also given. (au)

  12. Robust and sensitive analysis of mouse knockout phenotypes.

    Directory of Open Access Journals (Sweden)

    Natasha A Karp

    Full Text Available A significant challenge of in-vivo studies is the identification of phenotypes with a method that is robust and reliable. The challenge arises from practical issues that lead to experimental designs which are not ideal. Breeding issues, particularly in the presence of fertility or fecundity problems, frequently lead to data being collected in multiple batches. This problem is acute in high throughput phenotyping programs. In addition, in a high throughput environment operational issues lead to controls not being measured on the same day as knockouts. We highlight how application of traditional methods, such as a Student's t-Test or a 2-way ANOVA, in these situations give flawed results and should not be used. We explore the use of mixed models using worked examples from Sanger Mouse Genome Project focusing on Dual-Energy X-Ray Absorptiometry data for the analysis of mouse knockout data and compare to a reference range approach. We show that mixed model analysis is more sensitive and less prone to artefacts allowing the discovery of subtle quantitative phenotypes essential for correlating a gene's function to human disease. We demonstrate how a mixed model approach has the additional advantage of being able to include covariates, such as body weight, to separate effect of genotype from these covariates. This is a particular issue in knockout studies, where body weight is a common phenotype and will enhance the precision of assigning phenotypes and the subsequent selection of lines for secondary phenotyping. The use of mixed models with in-vivo studies has value not only in improving the quality and sensitivity of the data analysis but also ethically as a method suitable for small batches which reduces the breeding burden of a colony. This will reduce the use of animals, increase throughput, and decrease cost whilst improving the quality and depth of knowledge gained.

  13. Overview of methods for uncertainty analysis and sensitivity analysis in probabilistic risk assessment

    International Nuclear Information System (INIS)

    Iman, R.L.; Helton, J.C.

    1985-01-01

    Probabilistic Risk Assessment (PRA) is playing an increasingly important role in the nuclear reactor regulatory process. The assessment of uncertainties associated with PRA results is widely recognized as an important part of the analysis process. One of the major criticisms of the Reactor Safety Study was that its representation of uncertainty was inadequate. The desire for the capability to treat uncertainties with the MELCOR risk code being developed at Sandia National Laboratories is indicative of the current interest in this topic. However, as yet, uncertainty analysis and sensitivity analysis in the context of PRA is a relatively immature field. In this paper, available methods for uncertainty analysis and sensitivity analysis in a PRA are reviewed. This review first treats methods for use with individual components of a PRA and then considers how these methods could be combined in the performance of a complete PRA. In the context of this paper, the goal of uncertainty analysis is to measure the imprecision in PRA outcomes of interest, and the goal of sensitivity analysis is to identify the major contributors to this imprecision. There are a number of areas that must be considered in uncertainty analysis and sensitivity analysis for a PRA: (1) information, (2) systems analysis, (3) thermal-hydraulic phenomena/fission product behavior, (4) health and economic consequences, and (5) display of results. Each of these areas and the synthesis of them into a complete PRA are discussed

  14. A sensitivity analysis of hazardous waste disposal site climatic and soil design parameters using HELP3

    International Nuclear Information System (INIS)

    Adelman, D.D.; Stansbury, J.

    1997-01-01

    The Resource Conservation and Recovery Act (RCRA) Subtitle C, Comprehensive Environmental Response, Compensation, And Liability Act (CERCLA), and subsequent amendments have formed a comprehensive framework to deal with hazardous wastes on the national level. Key to this waste management is guidance on design (e.g., cover and bottom leachate control systems) of hazardous waste landfills. The objective of this research was to investigate the sensitivity of leachate volume at hazardous waste disposal sites to climatic, soil cover, and vegetative cover (Leaf Area Index) conditions. The computer model HELP3 which has the capability to simulate double bottom liner systems as called for in hazardous waste disposal sites was used in the analysis. HELP3 was used to model 54 combinations of climatic conditions, disposal site soil surface curve numbers, and leaf area index values to investigate how sensitive disposal site leachate volume was to these three variables. Results showed that leachate volume from the bottom double liner system was not sensitive to these parameters. However, the cover liner system leachate volume was quite sensitive to climatic conditions and less sensitive to Leaf Area Index and curve number values. Since humid locations had considerably more cover liner system leachate volume than and locations, different design standards may be appropriate for humid conditions than for and conditions

  15. Sensitivity Analysis Of Financing Demand In Syariah Banking

    Directory of Open Access Journals (Sweden)

    DR. HJ. ROSYETTI

    2017-11-01

    Full Text Available This study aims to analyze the Sensitivity of Demand Financing in syariah banking with a focus on the elasticity of financing demand income elasticity and cross elasticity. The type of data used in this study is secondary data quantitative and time series obtained from the publication of BPS BI and OJK. The data analysis technique begins by estimating multiple linear regression equations using the Eviews Application further measuring the sensitivity using elasticity. The research variables consist of revenue gross domestic product and conventional bank interest rate as independent variables and demand for financing as a dependent variable. The results obtained for the results gross domestic product and interest rate of conventional banks simultaneously affect the demand for financing in Islamic banking with a significant level of 5 obtained probability value F statistic amp945 005. Partially revenue share and gross domestic product have a significant effect on demand for financing. While the variable interest rate of conventional banks partially does not have a significant effect on demand for financing in Islamic banking. The ability of the three independent variables to explain the dependent variable of 99.06 the rest of 0.04 influenced by other factors outside this study. The sensitive value of demand for financing in syariah banking during the observation period was 3.94 amp400P 1 so that it can be said that demand for financing in syariah banking is elastic. The elasticity of income demand for financing in syariah banking during the observation period of 3.08 amp400I 1 is categorized as luxuries goods. The cross elasticity value of financing demand in syariah banking during the observation period is 0.52 or positive amp400C 0 it can be categorized that the interest rate of a conventional bank is a substitute of profit sharing.

  16. Below-surface analysis of inclusions with PIXE and PIGE

    International Nuclear Information System (INIS)

    MacArthur, J.D.; Ma, X.P.; Palmer, G.R.; Anderson, A.J.; Clark, A.H.

    1990-01-01

    The composition of fluid inclusions in host minerals holds much information about the chemical environment of mineral formation. When solid inclusions are exposed through polishing, their content can readily be investigated with an electron or proton probe. However, with an electron probe, only the daughter minerals or the residue material left when a fluid inclusion is opened can be analyzed since electrons with energies of tens of keV cannot penetrate to the unexposed inclusion. On the other hand, proton beams of a few MeV can penetrate a few tens of μm of material and still be able to excite characteristic radiation. This phenomenon has been exploited for the analysis of subsurface inclusions. Ideally, standard petrographic sections are polished to that inclusions, targetted for analysis, are brought to within 10 μm of the surface. The overlying matrix reduces the sensitivity of PIXE for the elements of low Z such as Na and Al because of the attenuation of the X-rays. However, these elements, as well as elements of even lower Z, which cannot be analyzed with the electron probe, can readily be detected with PIGE at good sensitivity. (orig.)

  17. Optimization of dye extraction from Cordyline fruticosa via response surface methodology to produce a natural sensitizer for dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Mahmoud A.M. Al-Alwani

    Full Text Available In the present work, the application of response surface methodology (RSM for the optimization of process parameters in the chlorophyll extraction from Cordyline fruticosa leaves was performed. The absorbance of the extract obtained from the extraction process under different conditions was estimated using the D-optimal design in RSM. Three different process parameters such as the nature of organic solvent based on their boiling point (ethanol, methanol, and acetonitrile, pH (4–8 and extraction temperature (50–90 °C were optimized for chlorophyll extraction. The effects of these parameters on the absorbance or concentration of the extract were evaluated using ANOVA results of quadratic polynomial regression. The results showed a high R2 and adjusted R2 correlation coefficients of 0.9963 and 0.9921 respectively. Moreover, the analysis of the final quadric model based on the design experiments indicated an optimal extraction condition of pH of 7.99, extraction temperature of 78.33 °C, and a solvent boiling point, 78 °C. The predicted absorbance was 1.006, which is in good agreement with the experimentally obtained result of 1.04 at 665 nm wavelength. The application of pigment obtained under the optimal condition was further evaluated as a sensitizer for the dye sensitized solar cells. Maximum solar conversion efficiency (η of 0.5% was achieved for the C. fruticosa leaf extract obtained under the optimum extraction conditions. Furthermore, the exposure of the leaf pigment to 100 mW/cm2 simulated sunlight yielded a short circuit photocurrent density (Isc of 1.3 mA, open circuit voltage (Voc of 616 mV, and a fill factor (ff of 60.16%. Keywords: Optimization, Cordyline fruticosa, Chlorophyll, Process variables, D-optimal design, Solar cells

  18. Nominal Range Sensitivity Analysis of peak radionuclide concentrations in randomly heterogeneous aquifers

    International Nuclear Information System (INIS)

    Cadini, F.; De Sanctis, J.; Cherubini, A.; Zio, E.; Riva, M.; Guadagnini, A.

    2012-01-01

    Highlights: ► Uncertainty quantification problem associated with the radionuclide migration. ► Groundwater transport processes simulated within a randomly heterogeneous aquifer. ► Development of an automatic sensitivity analysis for flow and transport parameters. ► Proposal of a Nominal Range Sensitivity Analysis approach. ► Analysis applied to the performance assessment of a nuclear waste repository. - Abstract: We consider the problem of quantification of uncertainty associated with radionuclide transport processes within a randomly heterogeneous aquifer system in the context of performance assessment of a near-surface radioactive waste repository. Radionuclide migration is simulated at the repository scale through a Monte Carlo scheme. The saturated groundwater flow and transport equations are then solved at the aquifer scale for the assessment of the expected radionuclide peak concentration at a location of interest. A procedure is presented to perform the sensitivity analysis of this target environmental variable to key parameters that characterize flow and transport processes in the subsurface. The proposed procedure is exemplified through an application to a realistic case study.

  19. A sensitivity analysis of the WIPP disposal room model: Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Labreche, D.A.; Beikmann, M.A. [RE/SPEC, Inc., Albuquerque, NM (United States); Osnes, J.D. [RE/SPEC, Inc., Rapid City, SD (United States); Butcher, B.M. [Sandia National Labs., Albuquerque, NM (United States)

    1995-07-01

    The WIPP Disposal Room Model (DRM) is a numerical model with three major components constitutive models of TRU waste, crushed salt backfill, and intact halite -- and several secondary components, including air gap elements, slidelines, and assumptions on symmetry and geometry. A sensitivity analysis of the Disposal Room Model was initiated on two of the three major components (waste and backfill models) and on several secondary components as a group. The immediate goal of this component sensitivity analysis (Phase I) was to sort (rank) model parameters in terms of their relative importance to model response so that a Monte Carlo analysis on a reduced set of DRM parameters could be performed under Phase II. The goal of the Phase II analysis will be to develop a probabilistic definition of a disposal room porosity surface (porosity, gas volume, time) that could be used in WIPP Performance Assessment analyses. This report documents a literature survey which quantifies the relative importance of the secondary room components to room closure, a differential analysis of the creep consolidation model and definition of a follow-up Monte Carlo analysis of the model, and an analysis and refitting of the waste component data on which a volumetric plasticity model of TRU drum waste is based. A summary, evaluation of progress, and recommendations for future work conclude the report.

  20. Goal-oriented sensitivity analysis for lattice kinetic Monte Carlo simulations.

    Science.gov (United States)

    Arampatzis, Georgios; Katsoulakis, Markos A

    2014-03-28

    In this paper we propose a new class of coupling methods for the sensitivity analysis of high dimensional stochastic systems and in particular for lattice Kinetic Monte Carlo (KMC). Sensitivity analysis for stochastic systems is typically based on approximating continuous derivatives with respect to model parameters by the mean value of samples from a finite difference scheme. Instead of using independent samples the proposed algorithm reduces the variance of the estimator by developing a strongly correlated-"coupled"- stochastic process for both the perturbed and unperturbed stochastic processes, defined in a common state space. The novelty of our construction is that the new coupled process depends on the targeted observables, e.g., coverage, Hamiltonian, spatial correlations, surface roughness, etc., hence we refer to the proposed method as goal-oriented sensitivity analysis. In particular, the rates of the coupled Continuous Time Markov Chain are obtained as solutions to a goal-oriented optimization problem, depending on the observable of interest, by considering the minimization functional of the corresponding variance. We show that this functional can be used as a diagnostic tool for the design and evaluation of different classes of couplings. Furthermore, the resulting KMC sensitivity algorithm has an easy implementation that is based on the Bortz-Kalos-Lebowitz algorithm's philosophy, where events are divided in classes depending on level sets of the observable of interest. Finally, we demonstrate in several examples including adsorption, desorption, and diffusion Kinetic Monte Carlo that for the same confidence interval and observable, the proposed goal-oriented algorithm can be two orders of magnitude faster than existing coupling algorithms for spatial KMC such as the Common Random Number approach. We also provide a complete implementation of the proposed sensitivity analysis algorithms, including various spatial KMC examples, in a supplementary MATLAB

  1. Goal-oriented sensitivity analysis for lattice kinetic Monte Carlo simulations

    International Nuclear Information System (INIS)

    Arampatzis, Georgios; Katsoulakis, Markos A.

    2014-01-01

    In this paper we propose a new class of coupling methods for the sensitivity analysis of high dimensional stochastic systems and in particular for lattice Kinetic Monte Carlo (KMC). Sensitivity analysis for stochastic systems is typically based on approximating continuous derivatives with respect to model parameters by the mean value of samples from a finite difference scheme. Instead of using independent samples the proposed algorithm reduces the variance of the estimator by developing a strongly correlated-“coupled”- stochastic process for both the perturbed and unperturbed stochastic processes, defined in a common state space. The novelty of our construction is that the new coupled process depends on the targeted observables, e.g., coverage, Hamiltonian, spatial correlations, surface roughness, etc., hence we refer to the proposed method as goal-oriented sensitivity analysis. In particular, the rates of the coupled Continuous Time Markov Chain are obtained as solutions to a goal-oriented optimization problem, depending on the observable of interest, by considering the minimization functional of the corresponding variance. We show that this functional can be used as a diagnostic tool for the design and evaluation of different classes of couplings. Furthermore, the resulting KMC sensitivity algorithm has an easy implementation that is based on the Bortz–Kalos–Lebowitz algorithm's philosophy, where events are divided in classes depending on level sets of the observable of interest. Finally, we demonstrate in several examples including adsorption, desorption, and diffusion Kinetic Monte Carlo that for the same confidence interval and observable, the proposed goal-oriented algorithm can be two orders of magnitude faster than existing coupling algorithms for spatial KMC such as the Common Random Number approach. We also provide a complete implementation of the proposed sensitivity analysis algorithms, including various spatial KMC examples, in a supplementary

  2. About the use of rank transformation in sensitivity analysis of model output

    International Nuclear Information System (INIS)

    Saltelli, Andrea; Sobol', Ilya M

    1995-01-01

    Rank transformations are frequently employed in numerical experiments involving a computational model, especially in the context of sensitivity and uncertainty analyses. Response surface replacement and parameter screening are tasks which may benefit from a rank transformation. Ranks can cope with nonlinear (albeit monotonic) input-output distributions, allowing the use of linear regression techniques. Rank transformed statistics are more robust, and provide a useful solution in the presence of long tailed input and output distributions. As is known to practitioners, care must be employed when interpreting the results of such analyses, as any conclusion drawn using ranks does not translate easily to the original model. In the present note an heuristic approach is taken, to explore, by way of practical examples, the effect of a rank transformation on the outcome of a sensitivity analysis. An attempt is made to identify trends, and to correlate these effects to a model taxonomy. Employing sensitivity indices, whereby the total variance of the model output is decomposed into a sum of terms of increasing dimensionality, we show that the main effect of the rank transformation is to increase the relative weight of the first order terms (the 'main effects'), at the expense of the 'interactions' and 'higher order interactions'. As a result the influence of those parameters which influence the output mostly by way of interactions may be overlooked in an analysis based on the ranks. This difficulty increases with the dimensionality of the problem, and may lead to the failure of a rank based sensitivity analysis. We suggest that the models can be ranked, with respect to the complexity of their input-output relationship, by mean of an 'Association' index I y . I y may complement the usual model coefficient of determination R y 2 as a measure of model complexity for the purpose of uncertainty and sensitivity analysis

  3. Trace drug analysis by surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Farquharson, Stuart; Lee, Vincent Y.

    2000-12-01

    Drug overdose involves more than 10 percent of emergency room (ER) cases, and a method to rapidly identify and quantify the abused drug is critical to the ability of the ER physician to administer the appropriate care. To this end, we have been developing a surface-enhanced Raman (SER) active material capable of detecting target drugs at physiological concentrations in urine. The SER-active material consists of a metal-doped sol-gel that provides not only a million fold increase in sensitivity but also reproducible measurements. The porous silica network offers a unique environment for stabilizing SER active metal particles and the high surface area increase the interaction between the analyte and metal particles. The sol-gel has been coated on the inside walls of glass samples vials, such that urine specimens may simply be introduced for analysis. Here we present the surface-enhanced Raman spectra of a series of barbiturates, actual urine specimens, and a drug 'spiked' urine specimen. The utility of pH adjustment to suppress dominant biochemicals associated with urine is also presented.

  4. Simplified procedures for fast reactor fuel cycle and sensitivity analysis

    International Nuclear Information System (INIS)

    Badruzzaman, A.

    1979-01-01

    The Continuous Slowing Down-Integral Transport Theory has been extended to perform criticality calculations in a Fast Reactor Core-blanket system achieving excellent prediction of the spectrum and the eigenvalue. The integral transport parameters did not need recalculation with source iteration and were found to be relatively constant with exposure. Fuel cycle parameters were accurately predicted when these were not varied, thus reducing a principal potential penalty of the Intergal Transport approach where considerable effort may be required to calculate transport parameters in more complicated geometries. The small variation of the spectrum in the central core region, and its weak dependence on exposure for both this region, the core blanket interface and blanket region led to the extension and development of inexpensive simplified procedures to complement exact methods. These procedures gave accurate predictions of the key fuel cycle parameters such as cost and their sensitivity to variation in spectrum-averaged and multigroup cross sections. They also predicted the implications of design variation on these parameters very well. The accuracy of these procedures and their use in analyzing a wide variety of sensitivities demonstrate the potential utility of survey calculations in Fast Reactor analysis and fuel management

  5. Relative sensitivity analysis of the predictive properties of sloppy models.

    Science.gov (United States)

    Myasnikova, Ekaterina; Spirov, Alexander

    2018-01-25

    Commonly among the model parameters characterizing complex biological systems are those that do not significantly influence the quality of the fit to experimental data, so-called "sloppy" parameters. The sloppiness can be mathematically expressed through saturating response functions (Hill's, sigmoid) thereby embodying biological mechanisms responsible for the system robustness to external perturbations. However, if a sloppy model is used for the prediction of the system behavior at the altered input (e.g. knock out mutations, natural expression variability), it may demonstrate the poor predictive power due to the ambiguity in the parameter estimates. We introduce a method of the predictive power evaluation under the parameter estimation uncertainty, Relative Sensitivity Analysis. The prediction problem is addressed in the context of gene circuit models describing the dynamics of segmentation gene expression in Drosophila embryo. Gene regulation in these models is introduced by a saturating sigmoid function of the concentrations of the regulatory gene products. We show how our approach can be applied to characterize the essential difference between the sensitivity properties of robust and non-robust solutions and select among the existing solutions those providing the correct system behavior at any reasonable input. In general, the method allows to uncover the sources of incorrect predictions and proposes the way to overcome the estimation uncertainties.

  6. Sensitivity analysis of energy demands on performance of CCHP system

    International Nuclear Information System (INIS)

    Li, C.Z.; Shi, Y.M.; Huang, X.H.

    2008-01-01

    Sensitivity analysis of energy demands is carried out in this paper to study their influence on performance of CCHP system. Energy demand is a very important and complex factor in the optimization model of CCHP system. Average, uncertainty and historical peaks are adopted to describe energy demands. The mix-integer nonlinear programming model (MINLP) which can reflect the three aspects of energy demands is established. Numerical studies are carried out based on energy demands of a hotel and a hospital. The influence of average, uncertainty and peaks of energy demands on optimal facility scheme and economic advantages of CCHP system are investigated. The optimization results show that the optimal GT's capacity and economy of CCHP system mainly lie on the average energy demands. Sum of capacities of GB and HE is equal to historical heating demand peaks, and sum of capacities of AR and ER are equal to historical cooling demand peaks. Maximum of PG is sensitive with historical peaks of energy demands and not influenced by uncertainty of energy demands, while the corresponding influence on DH is adverse

  7. Ensemble Solar Forecasting Statistical Quantification and Sensitivity Analysis: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, WanYin; Zhang, Jie; Florita, Anthony; Hodge, Bri-Mathias; Lu, Siyuan; Hamann, Hendrik F.; Sun, Qian; Lehman, Brad

    2015-12-08

    Uncertainties associated with solar forecasts present challenges to maintain grid reliability, especially at high solar penetrations. This study aims to quantify the errors associated with the day-ahead solar forecast parameters and the theoretical solar power output for a 51-kW solar power plant in a utility area in the state of Vermont, U.S. Forecasts were generated by three numerical weather prediction (NWP) models, including the Rapid Refresh, the High Resolution Rapid Refresh, and the North American Model, and a machine-learning ensemble model. A photovoltaic (PV) performance model was adopted to calculate theoretical solar power generation using the forecast parameters (e.g., irradiance, cell temperature, and wind speed). Errors of the power outputs were quantified using statistical moments and a suite of metrics, such as the normalized root mean squared error (NRMSE). In addition, the PV model's sensitivity to different forecast parameters was quantified and analyzed. Results showed that the ensemble model yielded forecasts in all parameters with the smallest NRMSE. The NRMSE of solar irradiance forecasts of the ensemble NWP model was reduced by 28.10% compared to the best of the three NWP models. Further, the sensitivity analysis indicated that the errors of the forecasted cell temperature attributed only approximately 0.12% to the NRMSE of the power output as opposed to 7.44% from the forecasted solar irradiance.

  8. A Sensitivity Analysis Approach to Identify Key Environmental Performance Factors

    Directory of Open Access Journals (Sweden)

    Xi Yu

    2014-01-01

    Full Text Available Life cycle assessment (LCA is widely used in design phase to reduce the product’s environmental impacts through the whole product life cycle (PLC during the last two decades. The traditional LCA is restricted to assessing the environmental impacts of a product and the results cannot reflect the effects of changes within the life cycle. In order to improve the quality of ecodesign, it is a growing need to develop an approach which can reflect the changes between the design parameters and product’s environmental impacts. A sensitivity analysis approach based on LCA and ecodesign is proposed in this paper. The key environmental performance factors which have significant influence on the products’ environmental impacts can be identified by analyzing the relationship between environmental impacts and the design parameters. Users without much environmental knowledge can use this approach to determine which design parameter should be first considered when (redesigning a product. A printed circuit board (PCB case study is conducted; eight design parameters are chosen to be analyzed by our approach. The result shows that the carbon dioxide emission during the PCB manufacture is highly sensitive to the area of PCB panel.

  9. In situ spectroscopic ellipsometry as a surface sensitive tool to probe thin film growth

    International Nuclear Information System (INIS)

    Liu, C.

    1999-01-01

    Sputtered thin film and multilayer x-ray mirrors are made routinely at the Advanced Photon Source (APS) for the APS users. Precise film growth control and characterization are very critical in fabricating high-quality x-ray mirrors. Film thickness calibrations are carried out using in situ and ex situ spectroscopic ellipsometry, interferometry, and x-ray scattering. To better understand the growth and optical properties of different thin film systems, we have carried out a systematic study of sputtered thin films of Au, Rh, Pg Pd, Cu, and Cr, using in situ ellipsometry. Multiple data sets were obtained in situ for each film material with incremental thicknesses and were analyzed with their correlation in mind. We found that in situ spectroscopic ellipsometry as a surface-sensitive tool can also be used to probe the growth and morphology of the thin film system. This application of in situ spectroscopic ellipsometry for metal thin film systems will be discussed

  10. Highly sensitive radioimmunoassay technique for subtyping the antibody to hepatitis B surface antigen

    Energy Technology Data Exchange (ETDEWEB)

    Fang, C T; Nath, N; Berberian, H; Dodd, R Y [American Red Cross, Blood Research Laboratory, Bethesda, MD, USA

    1978-12-01

    A highly sensitive technique for determining the subtype specificity of antibody to hepatitis B surface antigen (anti-HBs) is described. Immunoadsorbent consisting of controlled pore glass coated with subtype specific HBsAg was used to remove homologous antibody from the test samples before testing them for residual antibody by a commercially available radioimmunoassay (RIA). A total of 73 anti-HBs-positive samples from asymptomatic blood donors were tested. In nearly 80% of these samples the subtype reactivity could be determined by this technique. Only 67% could be typed by conventional liquid phase absorption RIA and 22% by passive hemagglutination inhibition techniques. Among the samples with low anti-HBs titer, ad and ay subtypes were found with equal frequency; however, with the increase in anti-HBs titer, considerably higher proportion of ad specificity was detected.

  11. A highly sensitive radioimmunoassay technique for subtyping the antibody to hepatitis B surface antigen

    International Nuclear Information System (INIS)

    Fang, C.T.; Nath, N.; Berberian, H.; Dodd, R.Y.

    1978-01-01

    A highly sensitive technique for determining the subtype specificity of antibody to hepatitis B surface antigen (anti-HBs) is described. Immunoadsorbent consisting of controlled pore glass coated with subtype specific HBsAg was used to remove homologous antibody from the test samples before testing them for residual antibody by a commercially available radioimmunoassay (RIA). A total of 73 anti-HBs-positive samples from asymptomatic blood donors were tested. In nearly 80% of these samples the subtype reactivity could be determined by this technique. Only 67% could be typed by conventional liquid phase absorption RIA and 22% by passive hemagglutination inhibition techniques. Among the samples with low anti-HBs titer, ad and ay subtypes were found with equal frequency; however, with the increase in anti-HBs titer, considerably higher proportion of ad specificity was detected. (Auth.)

  12. Global Surface Warming Hiatus Analysis Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data were used to conduct the study of the global surface warming hiatus, an apparent decrease in the upward trend of global surface temperatures since 1998....

  13. Sensitivity Study on Analysis of Reactor Containment Response to LOCA

    International Nuclear Information System (INIS)

    Chung, Ku Young; Sung, Key Yong

    2010-01-01

    As a reactor containment vessel is the final barrier to the release of radioactive material during design basis accidents (DBAs), its structural integrity must be maintained by withstanding the high pressure conditions resulting from DBAs. To verify the structural integrity of the containment, response analyses are performed to get the pressure transient inside the containment after DBAs, including loss of coolant accidents (LOCAs). The purpose of this study is to give regulative insights into the importance of input variables in the analysis of containment responses to a large break LOCA (LBLOCA). For the sensitivity study, a LBLOCA in Kori 3 and 4 nuclear power plant (NPP) is analyzed by CONTEMPT-LT computer code

  14. Sensitivity Study on Analysis of Reactor Containment Response to LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Ku Young; Sung, Key Yong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2010-10-15

    As a reactor containment vessel is the final barrier to the release of radioactive material during design basis accidents (DBAs), its structural integrity must be maintained by withstanding the high pressure conditions resulting from DBAs. To verify the structural integrity of the containment, response analyses are performed to get the pressure transient inside the containment after DBAs, including loss of coolant accidents (LOCAs). The purpose of this study is to give regulative insights into the importance of input variables in the analysis of containment responses to a large break LOCA (LBLOCA). For the sensitivity study, a LBLOCA in Kori 3 and 4 nuclear power plant (NPP) is analyzed by CONTEMPT-LT computer code

  15. Emissivity compensated spectral pyrometry—algorithm and sensitivity analysis

    International Nuclear Information System (INIS)

    Hagqvist, Petter; Sikström, Fredrik; Christiansson, Anna-Karin; Lennartson, Bengt

    2014-01-01

    In order to solve the problem of non-contact temperature measurements on an object with varying emissivity, a new method is herein described and evaluated. The method uses spectral radiance measurements and converts them to temperature readings. It proves to be resilient towards changes in spectral emissivity and tolerates noisy spectral measurements. It is based on an assumption of smooth changes in emissivity and uses historical values of spectral emissivity and temperature for estimating current spectral emissivity. The algorithm, its constituent steps and accompanying parameters are described and discussed. A thorough sensitivity analysis of the method is carried out through simulations. No rigorous instrument calibration is needed for the presented method and it is therefore industrially tractable. (paper)

  16. Sensitive Spectroscopic Analysis of Biomarkers in Exhaled Breath

    Science.gov (United States)

    Bicer, A.; Bounds, J.; Zhu, F.; Kolomenskii, A. A.; Kaya, N.; Aluauee, E.; Amani, M.; Schuessler, H. A.

    2018-06-01

    We have developed a novel optical setup which is based on a high finesse cavity and absorption laser spectroscopy in the near-IR spectral region. In pilot experiments, spectrally resolved absorption measurements of biomarkers in exhaled breath, such as methane and acetone, were carried out using cavity ring-down spectroscopy (CRDS). With a 172-cm-long cavity, an efficient optical path of 132 km was achieved. The CRDS technique is well suited for such measurements due to its high sensitivity and good spectral resolution. The detection limits for methane of 8 ppbv and acetone of 2.1 ppbv with spectral sampling of 0.005 cm-1 were achieved, which allowed to analyze multicomponent gas mixtures and to observe absorption peaks of 12CH4 and 13CH4. Further improvements of the technique have the potential to realize diagnostics of health conditions based on a multicomponent analysis of breath samples.

  17. Sequence length variation, indel costs, and congruence in sensitivity analysis

    DEFF Research Database (Denmark)

    Aagesen, Lone; Petersen, Gitte; Seberg, Ole

    2005-01-01

    The behavior of two topological and four character-based congruence measures was explored using different indel treatments in three empirical data sets, each with different alignment difficulties. The analyses were done using direct optimization within a sensitivity analysis framework in which...... the cost of indels was varied. Indels were treated either as a fifth character state, or strings of contiguous gaps were considered single events by using linear affine gap cost. Congruence consistently improved when indels were treated as single events, but no congruence measure appeared as the obviously...... preferable one. However, when combining enough data, all congruence measures clearly tended to select the same alignment cost set as the optimal one. Disagreement among congruence measures was mostly caused by a dominant fragment or a data partition that included all or most of the length variation...

  18. Global sensitivity analysis using low-rank tensor approximations

    International Nuclear Information System (INIS)

    Konakli, Katerina; Sudret, Bruno

    2016-01-01

    In the context of global sensitivity analysis, the Sobol' indices constitute a powerful tool for assessing the relative significance of the uncertain input parameters of a model. We herein introduce a novel approach for evaluating these indices at low computational cost, by post-processing the coefficients of polynomial meta-models belonging to the class of low-rank tensor approximations. Meta-models of this class can be particularly efficient in representing responses of high-dimensional models, because the number of unknowns in their general functional form grows only linearly with the input dimension. The proposed approach is validated in example applications, where the Sobol' indices derived from the meta-model coefficients are compared to reference indices, the latter obtained by exact analytical solutions or Monte-Carlo simulation with extremely large samples. Moreover, low-rank tensor approximations are confronted to the popular polynomial chaos expansion meta-models in case studies that involve analytical rank-one functions and finite-element models pertinent to structural mechanics and heat conduction. In the examined applications, indices based on the novel approach tend to converge faster to the reference solution with increasing size of the experimental design used to build the meta-model. - Highlights: • A new method is proposed for global sensitivity analysis of high-dimensional models. • Low-rank tensor approximations (LRA) are used as a meta-modeling technique. • Analytical formulas for the Sobol' indices in terms of LRA coefficients are derived. • The accuracy and efficiency of the approach is illustrated in application examples. • LRA-based indices are compared to indices based on polynomial chaos expansions.

  19. Two Dimensional Array of Piezoresistive Nanomechanical Membrane-Type Surface Stress Sensor (MSS with Improved Sensitivity

    Directory of Open Access Journals (Sweden)

    Nico F. de Rooij

    2012-11-01

    Full Text Available We present a new generation of piezoresistive nanomechanical Membrane-type Surface stress Sensor (MSS chips, which consist of a two dimensional array of MSS on a single chip. The implementation of several optimization techniques in the design and microfabrication improved the piezoresistive sensitivity by 3~4 times compared to the first generation MSS chip, resulting in a sensitivity about ~100 times better than a standard cantilever-type sensor and a few times better than optical read-out methods in terms of experimental signal-to-noise ratio. Since the integrated piezoresistive read-out of the MSS can meet practical requirements, such as compactness and not requiring bulky and expensive peripheral devices, the MSS is a promising transducer for nanomechanical sensing in the rapidly growing application fields in medicine, biology, security, and the environment. Specifically, its system compactness due to the integrated piezoresistive sensing makes the MSS concept attractive for the instruments used in mobile applications. In addition, the MSS can operate in opaque liquids, such as blood, where optical read-out techniques cannot be applied.

  20. Sensitivity Enhancement of Benzene Sensor Using Ethyl Cellulose-Coated Surface-Functionalized Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Thanattha Chobsilp

    2018-01-01

    Full Text Available A hybrid sensor based on the integration of functionalized multiwalled carbon nanotubes (MWCNTs with ethyl cellulose (EC was fabricated for sensitivity enhancement of benzene detection. To functionalize the surface of MWCNTs, MWCNTs were treated with hydrochloric acid for 60 min (A60-MWCNTs, while other MWCNTs were treated with oxygen plasma for 30, 60, 90, and 120 min (P30-MWCNTs, P60-MWCNTs, P90-MWCNTs, and P120-MWCNTs, resp.. Pristine MWCNTs, A-MWCNTs, and P-MWCNTs were dispersed in 1,2-dichloroethane, then dropped onto a printed circuit board consisting of Cu/Au electrodes used as the sensor platform. Next, EC was separately spin coated on the pristine MWCNTs, A-MWCNTs, and P-MWCNTs (EC/MWCNTs, EC/A-MWCNTs, and EC/P-MWCNTs, resp.. All sensors responded to benzene vapor at room temperature by increasing their electrical resistance which was sensitive to benzene vapor. The EC/P90-MWCNTs enabled an approximately 11-fold improvement in benzene detection compared to EC/MWCNTs. The sensitivity of all sensors would be attributed to the swelling of EC, resulting in the loosening of the MWCNT network after benzene vapor exposure. The differences of the sensing responses of the EC/MWCNTs, EC/A-MWCNTs, and EC/P-MWCNTs would be ascribed to the differences in crystallinity and functionalization of MWCNT sidewalls, suggesting that acid and oxygen plasma treatments of MWCNTs would be promising techniques for the improvement of benzene detection.

  1. Sensitivity analysis on various parameters for lattice analysis of DUPIC fuel with WIMS-AECL code

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Gyu Hong; Choi, Hang Bok; Park, Jee Won [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    The code WIMS-AECL has been used for the lattice analysis of DUPIC fuel. The lattice parameters calculated by the code is sensitive to the choice of number of parameters, such as the number of tracking lines, number of condensed groups, mesh spacing in the moderator region, other parameters vital to the calculation of probabilities and burnup analysis. We have studied this sensitivity with respect to these parameters and recommend their proper values which are necessary for carrying out the lattice analysis of DUPIC fuel.

  2. Sensitivity analysis on various parameters for lattice analysis of DUPIC fuel with WIMS-AECL code

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Gyu Hong; Choi, Hang Bok; Park, Jee Won [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    The code WIMS-AECL has been used for the lattice analysis of DUPIC fuel. The lattice parameters calculated by the code is sensitive to the choice of number of parameters, such as the number of tracking lines, number of condensed groups, mesh spacing in the moderator region, other parameters vital to the calculation of probabilities and burnup analysis. We have studied this sensitivity with respect to these parameters and recommend their proper values which are necessary for carrying out the lattice analysis of DUPIC fuel.

  3. Global sensitivity analysis using emulators, with an example analysis of large fire plumes based on FDS simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kelsey, Adrian [Health and Safety Laboratory, Harpur Hill, Buxton (United Kingdom)

    2015-12-15

    Laboratory (SNL) in 2009. At the largest LNG release rate the flames did not cover the entire area of the LNG spill, this behaviour had not been observed in previous large-scale experiments. Also the height of the flames was also greater than expected from previous large-scale tests. One possible explanation for the observed behaviour is that in this very large-scale release the speed at which air and fuel vapour was drawn into the fire exceeded the flame speed. Therefore the flames could not propagate upwind to ignite the whole surface of the LNG pool. Fuel vapour from the unignited region, drawn into the fire, may also account for the higher flame height. A global sensitivity analysis allows the influence of uncertain parameters on the quantities of interest to be examined. This publication and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

  4. An Overview of the Design and Analysis of Simulation Experiments for Sensitivity Analysis

    NARCIS (Netherlands)

    Kleijnen, J.P.C.

    2004-01-01

    Sensitivity analysis may serve validation, optimization, and risk analysis of simulation models.This review surveys classic and modern designs for experiments with simulation models.Classic designs were developed for real, non-simulated systems in agriculture, engineering, etc.These designs assume a

  5. Development of international standards for surface analysis by ISO technical committee 201 on surface chemical analysis

    International Nuclear Information System (INIS)

    Powell, C.J.

    1999-01-01

    Full text: The International Organization for Standardization (ISO) established Technical Committee 201 on Surface Chemical Analysis in 1991 to develop documentary standards for surface analysis. ISO/TC 201 met first in 1992 and has met annually since. This committee now has eight subcommittees (Terminology, General Procedures, Data Management and Treatment, Depth Profiling, AES, SIMS, XPS, and Glow Discharge Spectroscopy (GDS)) and one working group (Total X-Ray Fluorescence Spectroscopy). Each subcommittee has one or more working groups to develop standards on particular topics. Australia has observer-member status on ISO/TC 201 and on all ISO/TC 201 subcommittees except GDS where it has participator-member status. I will outline the organization of ISO/TC 201 and summarize the standards that have been or are being developed. Copyright (1999) Australian X-ray Analytical Association Inc

  6. O2 Plasma Etching and Antistatic Gun Surface Modifications for CNT Yarn Microelectrode Improve Sensitivity and Antifouling Properties.

    Science.gov (United States)

    Yang, Cheng; Wang, Ying; Jacobs, Christopher B; Ivanov, Ilia N; Venton, B Jill

    2017-05-16

    Carbon nanotube (CNT) based microelectrodes exhibit rapid and selective detection of neurotransmitters. While different fabrication strategies and geometries of CNT microelectrodes have been characterized, relatively little research has investigated ways to selectively enhance their electrochemical properties. In this work, we introduce two simple, reproducible, low-cost, and efficient surface modification methods for carbon nanotube yarn microelectrodes (CNTYMEs): O 2 plasma etching and antistatic gun treatment. O 2 plasma etching was performed by a microwave plasma system with oxygen gas flow and the optimized time for treatment was 1 min. The antistatic gun treatment flows ions by the electrode surface; two triggers of the antistatic gun was the optimized number on the CNTYME surface. Current for dopamine at CNTYMEs increased 3-fold after O 2 plasma etching and 4-fold after antistatic gun treatment. When the two treatments were combined, the current increased 12-fold, showing the two effects are due to independent mechanisms that tune the surface properties. O 2 plasma etching increased the sensitivity due to increased surface oxygen content but did not affect surface roughness while the antistatic gun treatment increased surface roughness but not oxygen content. The effect of tissue fouling on CNT yarns was studied for the first time, and the relatively hydrophilic surface after O 2 plasma etching provided better resistance to fouling than unmodified or antistatic gun treated CNTYMEs. Overall, O 2 plasma etching and antistatic gun treatment improve the sensitivity of CNTYMEs by different mechanisms, providing the possibility to tune the CNTYME surface and enhance sensitivity.

  7. Surface plasmon resonance effect of Cu nanoparticles in a dye sensitized solar cell

    International Nuclear Information System (INIS)

    Dhonde, Mahesh; Sahu, Kirti; Murty, V.V.S.; Nemala, Siva Sankar; Bhargava, Parag

    2017-01-01

    Highlights: •Pure and Cu-doped TiO 2 Nanoparticles are synthesized and incorporated in DSSCs. •Addition of Cu provided high surface area and reduced charge recombination due to LSPR effect. •The highest photo conversion efficiency achieved is 8.65% with J sc of 18.8 mA cm −2 . •This efficiency is 26% higher than that of pure TiO 2 DSSC. -- Abstract: Pure and copper doped titanium dioxide nanoparticles (TiO 2 NPs) for Dye Sensitized Solar Cell (DSSC) photo anodes with different doping amounts of copper (Cu) 0.1, 0.3 and 0.5 mole% are synthesized using modified sol-gel route. Addition of Cu in TiO 2 matrix can enhance absorption towards visible spectrum and can reduce the charge carrier recombination due to Localized Surface Plasmon Resonance (LSPR). The samples are characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), UV–vis spectroscopy (UV-VIS), X-ray Photoelectron Spectroscopy (XPS), Electro Chemical Impedance Spectroscopy (EIS). The crystallite size is measured by XRD and surface morphology of the samples is analyzed using SEM. UV–vis measurement shows that the influence of Cu in TiO 2 lattice altered its optical properties and extended absorption in the visible region. The resistances between different junctions of the cell are measured by EIS. The J-V measurement of the cell prepared using pure and Cu-doped TiO 2 NPs is carried out by solar simulator. The optimized Cu doped DSSC with 0.3 mole% Cu in TiO 2 shows the best power conversion efficiency of 8.65% which is approximately 26% greater than the efficiency of undoped DSSC (6.41%).

  8. Relative performance of academic departments using DEA with sensitivity analysis.

    Science.gov (United States)

    Tyagi, Preeti; Yadav, Shiv Prasad; Singh, S P

    2009-05-01

    The process of liberalization and globalization of Indian economy has brought new opportunities and challenges in all areas of human endeavor including education. Educational institutions have to adopt new strategies to make best use of the opportunities and counter the challenges. One of these challenges is how to assess the performance of academic programs based on multiple criteria. Keeping this in view, this paper attempts to evaluate the performance efficiencies of 19 academic departments of IIT Roorkee (India) through data envelopment analysis (DEA) technique. The technique has been used to assess the performance of academic institutions in a number of countries like USA, UK, Australia, etc. But we are using it first time in Indian context to the best of our knowledge. Applying DEA models, we calculate technical, pure technical and scale efficiencies and identify the reference sets for inefficient departments. Input and output projections are also suggested for inefficient departments to reach the frontier. Overall performance, research performance and teaching performance are assessed separately using sensitivity analysis.

  9. Analysis of painted arts by energy sensitive radiographic techniques with the Pixel Detector Timepix

    International Nuclear Information System (INIS)

    Zemlicka, J; Jakubek, J; Kroupa, M; Hradil, D; Hradilova, J; Mislerova, H

    2011-01-01

    Non-invasive techniques utilizing X-ray radiation offer a significant advantage in scientific investigations of painted arts and other cultural artefacts such as painted artworks or statues. In addition, there is also great demand for a mobile analytical and real-time imaging device given the fact that many fine arts cannot be transported. The highly sensitive hybrid semiconductor pixel detector, Timepix, is capable of detecting and resolving subtle and low-contrast differences in the inner composition of a wide variety of objects. Moreover, it is able to map the surface distribution of the contained elements. Several transmission and emission techniques are presented which have been proposed and tested for the analysis of painted artworks. This study focuses on the novel techniques of X-ray transmission radiography (conventional and energy sensitive) and X-ray induced fluorescence imaging (XRF) which can be realised at the table-top scale with the state-of-the-art pixel detector Timepix. Transmission radiography analyses the changes in the X-ray beam intensity caused by specific attenuation of different components in the sample. The conventional approach uses all energies from the source spectrum for the creation of the image while the energy sensitive alternative creates images in given energy intervals which enable identification and separation of materials. The XRF setup is based on the detection of characteristic radiation induced by X-ray photons through a pinhole geometry collimator. The XRF method is extremely sensitive to the material composition but it creates only surface maps of the elemental distribution. For the purpose of the analysis several sets of painted layers have been prepared in a restoration laboratory. The composition of these layers corresponds to those of real historical paintings from the 19 th century. An overview of the current status of our methods will be given with respect to the instrumentation and the application in the field of

  10. Analysis of painted arts by energy sensitive radiographic techniques with the Pixel Detector Timepix

    Energy Technology Data Exchange (ETDEWEB)

    Zemlicka, J; Jakubek, J; Kroupa, M [Institute of Experimental and Applied Physics, Czech Technical University Prague, Horska 3a/22, 128 00 Prague 2 (Czech Republic); Hradil, D [Institute of Inorganic Chemistry, AS CR, v.v.i., ALMA, 50 68 Husinec-Oeez (Czech Republic); Hradilova, J; Mislerova, H, E-mail: jan.zemlicka@utef.cvut.cz [Academy of Fine Arts in Prague, ALMA, U Akademie 4, 170 2, Prague 7 (Czech Republic)

    2011-01-15

    Non-invasive techniques utilizing X-ray radiation offer a significant advantage in scientific investigations of painted arts and other cultural artefacts such as painted artworks or statues. In addition, there is also great demand for a mobile analytical and real-time imaging device given the fact that many fine arts cannot be transported. The highly sensitive hybrid semiconductor pixel detector, Timepix, is capable of detecting and resolving subtle and low-contrast differences in the inner composition of a wide variety of objects. Moreover, it is able to map the surface distribution of the contained elements. Several transmission and emission techniques are presented which have been proposed and tested for the analysis of painted artworks. This study focuses on the novel techniques of X-ray transmission radiography (conventional and energy sensitive) and X-ray induced fluorescence imaging (XRF) which can be realised at the table-top scale with the state-of-the-art pixel detector Timepix. Transmission radiography analyses the changes in the X-ray beam intensity caused by specific attenuation of different components in the sample. The conventional approach uses all energies from the source spectrum for the creation of the image while the energy sensitive alternative creates images in given energy intervals which enable identification and separation of materials. The XRF setup is based on the detection of characteristic radiation induced by X-ray photons through a pinhole geometry collimator. The XRF method is extremely sensitive to the material composition but it creates only surface maps of the elemental distribution. For the purpose of the analysis several sets of painted layers have been prepared in a restoration laboratory. The composition of these layers corresponds to those of real historical paintings from the 19{sup th} century. An overview of the current status of our methods will be given with respect to the instrumentation and the application in the field

  11. PDASAC, Partial Differential Sensitivity Analysis of Stiff System

    International Nuclear Information System (INIS)

    Caracotsios, M.; Stewart, W.E.

    2001-01-01

    1 - Description of program or function: PDASAC solves stiff, nonlinear initial-boundary-value problems in a timelike dimension t and a space dimension x. Plane, circular cylindrical or spherical boundaries can be handled. Mixed-order systems of partial differential and algebraic equations can be analyzed with members of order or 0 or 1 in t, 0, 1 or 2 in x. Parametric sensitivities of the calculated states are computed simultaneously on request, via the Jacobian of the state equations. Initial and boundary conditions are efficiently reconciled. Local error control (in the max-norm or the 2-norm) is provided for the state vector and can include the parametric sensitivities if desired. 2 - Method of solution: The method of lines is used, with a user- selected x-grid and a minimum-bandwidth finite-difference approximations of the x-derivatives. Starting conditions are reconciled with a damped Newton algorithm adapted from Bain and Stewart (1991). Initial step selection is done by the first-order algorithms of Shampine (1987), extended here to differential- algebraic equation systems. The solution is continued with the DASSL predictor-corrector algorithm (Petzold 1983, Brenan et al. 1989) with the initial acceleration phase deleted and with row scaling of the Jacobian added. The predictor and corrector are expressed in divided-difference form, with the fixed-leading-coefficient form of corrector (Jackson and Sacks-Davis 1989; Brenan et al. 1989). Weights for the error tests are updated in each step with the user's tolerances at the predicted state. Sensitivity analysis is performed directly on the corrector equations of Caracotsios and Stewart (1985) and is extended here to the initialization when needed. 3 - Restrictions on the complexity of the problem: This algorithm, like DASSL, performs well on differential-algebraic equation systems of index 0 and 1 but not on higher-index systems; see Brenan et al. (1989). The user assigned the work array lengths and the output

  12. Surface Operations Data Analysis and Adaptation Tool, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This effort undertook the creation of a Surface Operations Data Analysis and Adaptation (SODAA) tool to store data relevant to airport surface research and...

  13. Management-oriented sensitivity analysis for pesticide transport in watershed-scale water quality modeling using SWAT

    International Nuclear Information System (INIS)

    Luo Yuzhou; Zhang Minghua

    2009-01-01

    The Soil and Water Assessment Tool (SWAT) was calibrated for hydrology conditions in an agricultural watershed of Orestimba Creek, California, and applied to simulate fate and transport of two organophosphate pesticides chlorpyrifos and diazinon. The model showed capability in evaluating pesticide fate and transport processes in agricultural fields and instream network. Management-oriented sensitivity analysis was conducted by applied stochastic SWAT simulations for pesticide distribution. Results of sensitivity analysis identified the governing processes in pesticide outputs as surface runoff, soil erosion, and sedimentation in the study area. By incorporating sensitive parameters in pesticide transport simulation, effects of structural best management practices (BMPs) in improving surface water quality were demonstrated by SWAT modeling. This study also recommends conservation practices designed to reduce field yield and in-stream transport capacity of sediment, such as filter strip, grassed waterway, crop residue management, and tailwater pond to be implemented in the Orestimba Creek watershed. - Selected structural BMPs are recommended for reducing loads of OP pesticides.

  14. Management-oriented sensitivity analysis for pesticide transport in watershed-scale water quality modeling using SWAT

    Energy Technology Data Exchange (ETDEWEB)

    Luo Yuzhou [University of California, Davis, CA 95616 (United States); Wenzhou Medical College, Wenzhou 325035 (China); Zhang Minghua, E-mail: mhzhang@ucdavis.ed [University of California, Davis, CA 95616 (United States); Wenzhou Medical College, Wenzhou 325035 (China)

    2009-12-15

    The Soil and Water Assessment Tool (SWAT) was calibrated for hydrology conditions in an agricultural watershed of Orestimba Creek, California, and applied to simulate fate and transport of two organophosphate pesticides chlorpyrifos and diazinon. The model showed capability in evaluating pesticide fate and transport processes in agricultural fields and instream network. Management-oriented sensitivity analysis was conducted by applied stochastic SWAT simulations for pesticide distribution. Results of sensitivity analysis identified the governing processes in pesticide outputs as surface runoff, soil erosion, and sedimentation in the study area. By incorporating sensitive parameters in pesticide transport simulation, effects of structural best management practices (BMPs) in improving surface water quality were demonstrated by SWAT modeling. This study also recommends conservation practices designed to reduce field yield and in-stream transport capacity of sediment, such as filter strip, grassed waterway, crop residue management, and tailwater pond to be implemented in the Orestimba Creek watershed. - Selected structural BMPs are recommended for reducing loads of OP pesticides.

  15. Management-oriented sensitivity analysis for pesticide transport in watershed-scale water quality modeling using SWAT.

    Science.gov (United States)

    Luo, Yuzhou; Zhang, Minghua

    2009-12-01

    The Soil and Water Assessment Tool (SWAT) was calibrated for hydrology conditions in an agricultural watershed of Orestimba Creek, California, and applied to simulate fate and transport of two organophosphate pesticides chlorpyrifos and diazinon. The model showed capability in evaluating pesticide fate and transport processes in agricultural fields and instream network. Management-oriented sensitivity analysis was conducted by applied stochastic SWAT simulations for pesticide distribution. Results of sensitivity analysis identified the governing processes in pesticide outputs as surface runoff, soil erosion, and sedimentation in the study area. By incorporating sensitive parameters in pesticide transport simulation, effects of structural best management practices (BMPs) in improving surface water quality were demonstrated by SWAT modeling. This study also recommends conservation practices designed to reduce field yield and in-stream transport capacity of sediment, such as filter strip, grassed waterway, crop residue management, and tailwater pond to be implemented in the Orestimba Creek watershed.

  16. Sensitivity Analysis for Steady State Groundwater Flow Using Adjoint Operators

    Science.gov (United States)

    Sykes, J. F.; Wilson, J. L.; Andrews, R. W.

    1985-03-01

    Adjoint sensitivity theory is currently being considered as a potential method for calculating the sensitivity of nuclear waste repository performance measures to the parameters of the system. For groundwater flow systems, performance measures of interest include piezometric heads in the vicinity of a waste site, velocities or travel time in aquifers, and mass discharge to biosphere points. The parameters include recharge-discharge rates, prescribed boundary heads or fluxes, formation thicknesses, and hydraulic conductivities. The derivative of a performance measure with respect to the system parameters is usually taken as a measure of sensitivity. To calculate sensitivities, adjoint sensitivity equations are formulated from the equations describing the primary problem. The solution of the primary problem and the adjoint sensitivity problem enables the determination of all of the required derivatives and hence related sensitivity coefficients. In this study, adjoint sensitivity theory is developed for equations of two-dimensional steady state flow in a confined aquifer. Both the primary flow equation and the adjoint sensitivity equation are solved using the Galerkin finite element method. The developed computer code is used to investigate the regional flow parameters of the Leadville Formation of the Paradox Basin in Utah. The results illustrate the sensitivity of calculated local heads to the boundary conditions. Alternatively, local velocity related performance measures are more sensitive to hydraulic conductivities.

  17. An Application of Monte-Carlo-Based Sensitivity Analysis on the Overlap in Discriminant Analysis

    Directory of Open Access Journals (Sweden)

    S. Razmyan

    2012-01-01

    Full Text Available Discriminant analysis (DA is used for the measurement of estimates of a discriminant function by minimizing their group misclassifications to predict group membership of newly sampled data. A major source of misclassification in DA is due to the overlapping of groups. The uncertainty in the input variables and model parameters needs to be properly characterized in decision making. This study combines DEA-DA with a sensitivity analysis approach to an assessment of the influence of banks’ variables on the overall variance in overlap in a DA in order to determine which variables are most significant. A Monte-Carlo-based sensitivity analysis is considered for computing the set of first-order sensitivity indices of the variables to estimate the contribution of each uncertain variable. The results show that the uncertainties in the loans granted and different deposit variables are more significant than uncertainties in other banks’ variables in decision making.

  18. Pressurized thermal shock probabilistic fracture mechanics sensitivity analysis for Yankee Rowe reactor pressure vessel

    International Nuclear Information System (INIS)

    Dickson, T.L.; Cheverton, R.D.; Bryson, J.W.; Bass, B.R.; Shum, D.K.M.; Keeney, J.A.

    1993-08-01

    The Nuclear Regulatory Commission (NRC) requested Oak Ridge National Laboratory (ORNL) to perform a pressurized-thermal-shock (PTS) probabilistic fracture mechanics (PFM) sensitivity analysis for the Yankee Rowe reactor pressure vessel, for the fluences corresponding to the end of operating cycle 22, using a specific small-break-loss- of-coolant transient as the loading condition. Regions of the vessel with distinguishing features were to be treated individually -- upper axial weld, lower axial weld, circumferential weld, upper plate spot welds, upper plate regions between the spot welds, lower plate spot welds, and the lower plate regions between the spot welds. The fracture analysis methods used in the analysis of through-clad surface flaws were those contained in the established OCA-P computer code, which was developed during the Integrated Pressurized Thermal Shock (IPTS) Program. The NRC request specified that the OCA-P code be enhanced for this study to also calculate the conditional probabilities of failure for subclad flaws and embedded flaws. The results of this sensitivity analysis provide the NRC with (1) data that could be used to assess the relative influence of a number of key input parameters in the Yankee Rowe PTS analysis and (2) data that can be used for readily determining the probability of vessel failure once a more accurate indication of vessel embrittlement becomes available. This report is designated as HSST report No. 117

  19. Global sensitivity analysis in the identification of cohesive models using full-field kinematic data

    KAUST Repository

    Alfano, Marco; Lubineau, Gilles; Paulino, Glá ucio Hermogenes

    2015-01-01

    Failure of adhesive bonded structures often occurs concurrent with the formation of a non-negligible fracture process zone in front of a macroscopic crack. For this reason, the analysis of damage and fracture is effectively carried out using the cohesive zone model (CZM). The crucial aspect of the CZM approach is the precise determination of the traction-separation relation. Yet it is usually determined empirically, by using calibration procedures combining experimental data, such as load-displacement or crack length data, with finite element simulation of fracture. Thanks to the recent progress in image processing, and the availability of low-cost CCD cameras, it is nowadays relatively easy to access surface displacements across the fracture process zone using for instance Digital Image Correlation (DIC). The rich information provided by correlation techniques prompted the development of versatile inverse parameter identification procedures combining finite element (FE) simulations and full field kinematic data. The focus of the present paper is to assess the effectiveness of these methods in the identification of cohesive zone models. In particular, the analysis is developed in the framework of the variance based global sensitivity analysis. The sensitivity of kinematic data to the sought cohesive properties is explored through the computation of the so-called Sobol sensitivity indexes. The results show that the global sensitivity analysis can help to ascertain the most influential cohesive parameters which need to be incorporated in the identification process. In addition, it is shown that suitable displacement sampling in time and space can lead to optimized measurements for identification purposes.

  20. Global sensitivity analysis in the identification of cohesive models using full-field kinematic data

    KAUST Repository

    Alfano, Marco

    2015-03-01

    Failure of adhesive bonded structures often occurs concurrent with the formation of a non-negligible fracture process zone in front of a macroscopic crack. For this reason, the analysis of damage and fracture is effectively carried out using the cohesive zone model (CZM). The crucial aspect of the CZM approach is the precise determination of the traction-separation relation. Yet it is usually determined empirically, by using calibration procedures combining experimental data, such as load-displacement or crack length data, with finite element simulation of fracture. Thanks to the recent progress in image processing, and the availability of low-cost CCD cameras, it is nowadays relatively easy to access surface displacements across the fracture process zone using for instance Digital Image Correlation (DIC). The rich information provided by correlation techniques prompted the development of versatile inverse parameter identification procedures combining finite element (FE) simulations and full field kinematic data. The focus of the present paper is to assess the effectiveness of these methods in the identification of cohesive zone models. In particular, the analysis is developed in the framework of the variance based global sensitivity analysis. The sensitivity of kinematic data to the sought cohesive properties is explored through the computation of the so-called Sobol sensitivity indexes. The results show that the global sensitivity analysis can help to ascertain the most influential cohesive parameters which need to be incorporated in the identification process. In addition, it is shown that suitable displacement sampling in time and space can lead to optimized measurements for identification purposes.