scholarly journals Uncertainty Analysis for Topographic Correction of Hyperspectral Remote Sensing Images

2020 ◽  
Vol 12 (4) ◽  
pp. 705 ◽  
Author(s):  
Zhaoning Ma ◽  
Guorui Jia ◽  
Michael E. Schaepman ◽  
Huijie Zhao
Keyword(s):  
Uncertainty Analysis ◽  
Uncertainty Propagation ◽  
Spectral Feature ◽  
Metrological Traceability ◽  
Soil Surface ◽  
Topographic Correction ◽  
Uncertainty In Measurement ◽  
Hyperion Data ◽  
Set Up ◽  
Hyperspectral Remote Sensing Images

Quantitative uncertainty analysis is generally taken as an indispensable step in the calibration of a remote sensor. A full uncertainty propagation chain has not been established to set up the metrological traceability for surface reflectance inversed from remotely sensed images. As a step toward this goal, we proposed an uncertainty analysis method for the two typical semi-empirical topographic correction models, i.e., C and Minnaert, according to the ‘Guide to the Expression of Uncertainty in Measurement (GUM)’. We studied the data link and analyzed the uncertainty propagation chain from the digital elevation model (DEM) and at-sensor radiance data to the topographic corrected radiance. We obtained spectral uncertainty characteristics of the topographic corrected radiance as well as its uncertainty components associated with all of the input quantities by using a set of Earth Observation-1 (EO-1) Hyperion data acquired over a rugged soil surface partly covered with snow. Firstly, the relative uncertainty of cover types with lower radiance values was larger for both C and Minnaert corrections. Secondly, the trend of at-sensor radiance contributed to a spectral feature, where the uncertainty of the topographic corrected radiance was poor in bands below 1400 nm. Thirdly, the uncertainty components associated with at-sensor radiance, slope, and aspect dominated the total combined uncertainty of corrected radiance. It was meaningful to reduce the uncertainties of at-sensor radiance, slope, and aspect for reducing the uncertainty of corrected radiance and improving the data quality. We also gave some suggestions to reduce the uncertainty of slope and aspect data.

scholarly journals The dependence of maize (Zea mays) hybrids yielding potential on the water amounts reaching the soil surface

Genetika ◽  
2013 ◽  
Vol 45 (1) ◽  
pp. 261-272 ◽  
Author(s):  
Branka Kresovic ◽  
Vesna Dragicevic ◽  
Bosko Gajic ◽  
Angelina Tapanarova ◽  
Borivoj Pejic
Keyword(s):  
Zea Mays ◽  
Soil Moisture ◽  
Block Design ◽  
Soil Surface ◽  
Growing Season ◽  
Maize Hybrids ◽  
Water Capacity ◽  
Set Up ◽  
Water Amount

The aim of the present study was to observe the response of maize hybrids under rainfed and irrigation conditions of the soil in order to establish the dependence of yielding potential on the water amounts reaching the soil surface during the growing season. The four-replicate trail was set up according to the randomised complete-block design on chernozem. Pre-watering soil moisture was approximately 70% of field water capacity, and soil moisture was established thermogravimetrically. During the five-year studies, the following differences in yields could be as follows: 12.68 t ha-1 (ZP 341); 12.76 t ha-1 (ZP 434); 13.17 t ha-1 (ZP 578); 14.03 t ha-1 (ZP 684) and 13.75 t ha-1 (ZP 704) under conditions of 440 mm, 440 mm, 424 mm, 457 mm and 466 mm of water, respectively. The hybrid ZP 341, i.e. ZP 578 expressed the highest, i.e. the lowest tolerance in dry relative seasons, respectively. The reduction of the water amount for every 10 mm decreased the yield by 119.4 kg ha-1 (ZP 341), 156.7 kg ha-1 (ZP 434), 172.3 kg ha-1 (ZP 578), 148.9 kg ha-1 (ZP 684) and 151.1 kg ha-1 (ZP 704).

Uncertainty Evaluation on Multi-Hole Aerodynamic Pressure Probes

2020 ◽  
Author(s):  
Andrea Notaristefano ◽  
Paolo Gaetani ◽  
Vincenzo Dossena ◽  
Alberto Fusetti
Keyword(s):  
Uncertainty Analysis ◽  
Evaluation Method ◽  
Experimental Testing ◽  
Uncertainty Propagation ◽  
Calibration Procedure ◽  
Fast Response ◽  
Uncertainty Evaluation ◽  
Sensor Calibration ◽  
Pressure Probe ◽  
Aerodynamic Pressure

Abstract In the frame of a continuous improvement of the performance and accuracy in the experimental testing of turbomachines, the uncertainty analysis on measurements instrumentation and techniques is of paramount importance. For this reason, since the beginning of the experimental activities at the Laboratory of Fluid Machines (LFM) located at Politecnico di Milano (Italy), this issue has been addressed and different methodologies have been applied. This paper proposes a comparison of the results collected applying two methods for the measurement uncertainty quantification to two different aerodynamic pressure probes: sensor calibration, aerodynamic calibration and probe application are considered. The first uncertainty evaluation method is the so called “Uncertainty Propagation” method (UPM); the second is based on the “Monte Carlo” method (MCM). Two miniaturized pressure probes have been selected for this investigation: a pneumatic 5-hole probe and a spherical fast response aerodynamic pressure probe (sFRAPP), the latter applied as a virtual 4-hole probe. Since the sFRAPP is equipped with two miniaturized pressure transducers installed inside the probe head, a specific calibration procedure and a dedicated uncertainty analysis are required.

Bayesian Surrogate Learning for Uncertainty Analysis of Coupled Multidisciplinary Systems

2021 ◽  
Vol 21 (4) ◽  
Author(s):  
Seyede Fatemeh Ghoreishi ◽  
Mahdi Imani
Keyword(s):  
Uncertainty Analysis ◽  
Closed Form ◽  
Uncertainty Propagation ◽  
Uncertainty Reduction ◽  
System Level ◽  
Engineering Systems ◽  
Sample Point ◽  
Design Variables ◽  
Multidisciplinary Systems ◽  
Stationary Behavior

Abstract Engineering systems are often composed of many subsystems that interact with each other. These subsystems, referred to as disciplines, contain many types of uncertainty and in many cases are feedback-coupled with each other. In designing these complex systems, one needs to assess the stationary behavior of these systems for the sake of stability and reliability. This requires the system level uncertainty analysis of the multidisciplinary systems, which is often computationally intractable. To overcome this issue, techniques have been developed for capturing the stationary behavior of the coupled multidisciplinary systems through available data of individual disciplines. The accuracy and convergence of the existing techniques depend on a large amount of data from all disciplines, which are not available in many practical problems. Toward this, we have developed an adaptive methodology that adds the minimum possible number of samples from individual disciplines to achieve an accurate and reliable uncertainty propagation in coupled multidisciplinary systems. The proposed method models each discipline function via Gaussian process (GP) regression to derive a closed-form policy. This policy sequentially selects a new sample point that results in the highest uncertainty reduction over the distribution of the coupling design variables. The effectiveness of the proposed method is demonstrated in the uncertainty analysis of an aerostructural system and a coupled numerical example.

Efficient Possibilistic Uncertainty Analysis of a Car Crash Scenario Using a Multifidelity Approach

2019 ◽  
Vol 5 (4) ◽  
Author(s):  
Markus Mäck ◽  
Michael Hanss
Keyword(s):  
Uncertainty Analysis ◽  
Large Scale ◽  
Uncertainty Propagation ◽  
Possibility Theory ◽  
Design Stage ◽  
High Fidelity ◽  
Zone Structure ◽  
Early Design Stage ◽  
Car Crash ◽  
Fidelity Model

Abstract The early design stage of mechanical structures is often characterized by unknown or only partially known boundary conditions and environmental influences. Particularly, in the case of safety-relevant components, such as the crumple zone structure of a car, those uncertainties must be appropriately quantified and accounted for in the design process. For this purpose, possibility theory provides a suitable tool for the modeling of incomplete information and uncertainty propagation. However, the numerical propagation of uncertainty described by possibility theory is accompanied by high computational costs. The necessarily repeated model evaluations render the uncertainty analysis challenging to be realized if a model is complex and of large scale. Oftentimes, simplified and idealized models are used for the uncertainty analysis to speed up the simulation while accepting a loss of accuracy. The proposed multifidelity scheme for possibilistic uncertainty analysis, instead, takes advantage of the low costs of an inaccurate low-fidelity model and the accuracy of an expensive high-fidelity model. For this purpose, the functional dependency between the high- and low-fidelity model is exploited and captured in a possibilistic way. This results in a significant speedup for the uncertainty analysis while ensuring accuracy by using only a low number of expensive high-fidelity model evaluations. The proposed approach is applied to an automotive car crash scenario in order to emphasize its versatility and applicability.

scholarly journals A new in situ sensor for large-scale snow-cover monitoring

2004 ◽  
Vol 38 ◽  
pp. 273-278 ◽  
Author(s):  
Manfred Stähli ◽  
Markus Stacheder ◽  
David Gustafsson ◽  
Stefan Schlaeger ◽  
Martin Schneebeli ◽  
...  
Keyword(s):  
Large Scale ◽  
Snow Water Equivalent ◽  
Soil Surface ◽  
Test Site ◽  
Liquid Water Content ◽  
Flat Band ◽  
Snow Layer ◽  
In Situ Sensor ◽  
Set Up

AbstractA new in situ sensor for the simultaneous measurement of snow water equivalent, snow density and liquid-water content is presented in this paper. The system consists of radio frequency transmission lines of up to 25 m length cast in a flat PVC band, which can be set up either horizontally to monitor single snow-layer properties or sloping from a mast to the soil surface to determine vertical snowpack properties. The dielectric coefficient along the flat-band cable is measured with a time-domain reflectometer at high frequencies, and with a low-frequency impedance analyzer. The performance of the sensor system was tested during two winter seasons (2001–03) at the high-alpine test site Weissfluhjoch, Davos, Switzerland. The cable suspension and set-up of the sloping cable was shown to be critical with regard to stability and the formation of unwanted air gaps along the cable. Overall, the sensing system proved quite robust and produced results in agreement with manual snowpack observations.

Verification and Validation in Computational Fluid Dynamics and Heat Transfer Using Experimental Uncertainty Analysis Concepts

2005 ◽  
Author(s):  
Hugh W. Coleman
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Uncertainty Analysis ◽  
Performance Test ◽  
Verification And Validation ◽  
Experimental Uncertainty ◽  
Uncertainty In Measurement ◽  
American Society ◽  
Expression Of Uncertainty

An approach to verification and validation (V&V) using experimental uncertainty analysis concepts to quantify the result of a validation effort is discussed. This is the approach to V&V being drafted by the American Society of Mechanical Engineers (ASME) Performance Test Code Committee, PTC 61: Verification and Validation in Computational Fluid Dynamics and Heat Transfer. The charter of the committee is “Provides procedures for quantifying the accuracy of modeling and simulation in computational fluid dynamics and heat transfer.” The committee is initially focusing its efforts on drafting a standard for V&V in computational fluid dynamics and heat transfer based on the concepts and methods of experimental uncertainty analysis. This will leverage the decades of effort in the community of experimentalists that resulted in the ASME Standard PTC 19.1 “Test Uncertainty” and the ISO international standard “Guide to the Expression of Uncertainty in Measurement.”

scholarly journals Cloud and cluster computing in uncertainty analysis of integrated flood models

2012 ◽  
Vol 15 (1) ◽  
pp. 55-70 ◽  
Author(s):  
V. Moya Quiroga ◽  
I. Popescu ◽  
D. P. Solomatine ◽  
L. Bociort
Keyword(s):  
Uncertainty Analysis ◽  
Cluster Computing ◽  
Uncertainty Propagation ◽  
Integrated Approach ◽  
Computer Time ◽  
Monte Carlo Sampling ◽  
Water Levels ◽  
Efficient Technology ◽  
Management Actions ◽  
Complex Models

There is an increased awareness of the importance of flood management aimed at preventing human and material losses. A wide variety of numerical modelling tools have been developed in order to make decision-making more efficient, and to better target management actions. Hydroinformatics assumes the holistic integrated approach to managing the information propagating through models, and analysis of uncertainty propagation through models is an important part of such studies. Many popular approaches to uncertainty analysis typically involve various strategies of Monte Carlo sampling of uncertain variables and/or parameters and running a model a large number of times, so that in the case of complex river systems this procedure becomes very time-consuming. In this study the popular modelling systems HEC-HMS, HEC-RAS and Sobek1D2D were applied to modelling the hydraulics of the Timis–Bega basin in Romania. We considered the problem of studying how the flood inundation is influenced by uncertainties in water levels of the reservoirs in the catchment, and uncertainties in the digital elevation model (DEM) used in the 2D hydraulic model. For this we used cloud computing (Amazon Elastic Compute Cloud platform) and cluster computing on the basis of a number of office desktop computers, and were able to show their efficiency, leading to a considerable reduction of the required computer time for uncertainty analysis of complex models. The conducted experiments allowed us to associate probabilities to various areas prone to flooding. This study allows us to draw a conclusion that cloud and cluster computing offer an effective and efficient technology that makes uncertainty-aware modelling a practical possibility even when using complex models.

scholarly journals DISTRIBUIÇÃO DA EVAPORAÇÃO NO INTERIOR DE UM AMBIENTE PROTEGIDO.

Irriga ◽  
2006 ◽  
Vol 11 (2) ◽  
pp. 246-256
Author(s):  
Cleber Junior Jadoski ◽  
Antonio Evaldo Klar ◽  
Marcio Furlan Maggi ◽  
Juliana Ramiro Alexandre Barreto Almeida dos Santos ◽  
Samuel Rodrigues Fulan
Keyword(s):  
Energy Distribution ◽  
Spatial Variability ◽  
Soil Surface ◽  
Longitudinal Axis ◽  
Class A ◽  
Set Up ◽  
Equidistant Points ◽  
Class A Pan

DISTRIBUIÇÃO DA EVAPORAÇÃO NO INTERIOR DE UM AMBIENTE PROTEGIDO.  Cleber Junior Jadoski1; Antonio Evaldo Klar1; Marcio Furlan Maggi2; Juliana Ramiro1 Alexandre Barreto Almeida  dos Santos1;  Samuel Rodrigues Fulan11Departamento de Engenharia Rural, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, SP,  [email protected]  2Universidade Estadual do Centro Oeste, UNICENTRO, Guarapuava, PR   1 RESUMO. Este trabalho teve por objetivo estudar a distribuição da evaporação no interior de um ambiente protegido. O experimento foi instalado em uma estufa de polietileno na Fazenda Experimental Lageado da Faculdade de Ciências Agronômicas (FCA), no período do inverno de 2005. Para analisar a distribuição espacial da energia, foram utilizados microevaporímetros plásticos de 500 ml (13,7 cmde diâmetro) com o que foram obtidos os valores respectivos de evaporação que integram os elementos meteorológicos envolvidos. Foram instalados 132 microevaporímetros distribuídos em três alturas, 0,40, 0,80 e1,20 m, a partir da superfície do solo, perfazendo 44 pontos uniformemente distribuídos. A estufa plástica é do tipo túnel com 7,5m de largura por 27,5m de comprimento, 3,20m de altura no centro e 2,00m nas paredes laterais fechadas com tela do tipo “sombrite”. A orientação noroeste/sudeste, com base no norte verdadeiro, foi adotada para o eixo longitudinal da estufa. Para a comparação das variáveis, foram utilizados princípios de geoestatística com auxílio do programa GS+. Os dados obtidos permitiram chegar às seguintes conclusões: ocorreu variabilidade espacial nas diferentes regiões e alturas de instalação dos microevaporímetros, com maior evaporação na altura mais próxima do solo no mês de julho; o tanque Classe “A” não difere significativamente em relação aos microevaporímetros; pode-se estimar a evaporação interna do ambiente protegido através de medições em um tanque Classe “A” instalado fora do ambiente protegido. UNITERMOS: Geoestatística, microevaporímetro, tanque Classe “A”,  Jadoski, c. j.; KLAR, A. E.; MAGGI, M. F.; RAMIRO, J.; Santos,  a. b. a. dos;  Fulan S. R. EVAPORATION DISTRIBUTION IN A PROTECTED ENVIRONMENT  2 ABSTRACT             This work aimed to study evaporation distribution in a protected environment.  The experiment was set up in polyethylene greenhouse at the Lageado Experimental Farm in theSchoolofAgronomic Sciences(FCA, UNESP-Botucatu) in the  winter of  2005. 132  500-ml plastic micro evaporimeters  (13.7 diameter) were used used to obtain evaporation values and analyze spatial energy distribution. These micro evaporimeters were distributed in 44 equidistant points, at three different heights from the soil surface: 0.40, 0.80 and 1.20cm The tunnel-type greenhouse was7.5 mwide,27.5 mlong and  3.20 mhigh at the center, and was covered with black shadow screen (sombrite) on the sides.  Southeast /northwest orientation, based on true north, was used foro othe greenhouse longitudinal axis.  For variable comparison,  a geostatistics  was used through the  GS+ program. From obtained data, it was concluded that: there was spatial variability at different points and heights of the microevaporimeters and higher evaporation values for the height near to  soil surface in July; evaporation values   obtained from micro evaporimeters were not statistically different from those obtained from Class “A” Pan installed in the center of  the greenhouse; the Class “A” Pan installed outside the greenhouse can be used to evaluate the internal evaporation. KEYWORDS: Geostatistics, microevaporimeter, Class “A” Pan.. 

scholarly journals Effects of large macropores on soil evaporation in salt marshes

2020 ◽  
Author(s):  
Tingzhang Zhou ◽  
Pei Xin ◽  
Jirka Jirka Šimůnek
Keyword(s):  
Water Flow ◽  
Salt Marshes ◽  
Evaporation Rate ◽  
Preferential Flow ◽  
Soil Surface ◽  
Soil Evaporation ◽  
Infrared Light ◽  
Soil Conditions ◽  
Set Up ◽  
The Impact

<p>The occurrence of macropores in salt marsh sediments is a natural and ubiquitous phenomenon. Although they are widely assumed to significantly affect water flow in salt marshes, the effects are not well understood. We conducted physical laboratory experiments and numerical simulations to examine the impact of macropores on soil evaporation. Soil columns packed with either sand or clay and with or without macropores were set up with water tables in the columns set at different levels. A high potential evaporation rate was induced by infrared light and a fan. The results showed that in the soil with a low saturated hydraulic conductivity (and thus a low transport capacity), macropores behaved as preferential flow paths, delivering water from the groundwater towards the soil surface and maintaining a high evaporation rate in comparison with the soil without macropores. This effect was more pronounced for sediments with lower hydraulic conductivities and shallower groundwater tables. These results not only improve our understanding of water flow and soil conditions in salt marshes but also shed light on soil evaporation in other hydrological systems.</p>

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