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1.
Validation of GOES and MODIS active fire detection products using ASTER and ETM+ data 总被引:2,自引:0,他引:2
Wilfrid Schroeder Elaine Prins Louis Giglio Ivan Csiszar Christopher Schmidt Jeffrey Morisette Douglas Morton 《Remote sensing of environment》2008,112(5):2711-2726
In this study we implemented a comprehensive analysis to validate the MODIS and GOES satellite active fire detection products (MOD14 and WFABBA, respectively) and characterize their major sources of omission and commission errors which have important implications for a large community of fire data users. Our analyses were primarily based on the use of 30 m resolution ASTER and ETM+ imagery as our validation data. We found that at the 50% true positive detection probability mark, WFABBA requires four times more active fire area than is necessary for MOD14 to achieve the same probability of detection, despite the 16× factor separating the nominal spatial resolutions of the two products. Approximately 75% and 95% of all fires sampled were omitted by the MOD14 and WFABBA instantaneous products, respectively; whereas an omission error of 38% was obtained for WFABBA when considering the 30-minute interval of the GOES data. Commission errors for MOD14 and WFABBA were found to be similar and highly dependent on the vegetation conditions of the areas imaged, with the larger commission errors (approximately 35%) estimated over regions of active deforestation. Nonetheless, the vast majority (> 80%) of the commission errors were indeed associated with recent burning activity where scars could be visually confirmed in the higher resolution data. Differences in thermal dynamics of vegetated and non-vegetated areas were found to produce a reduction of approximately 50% in the commission errors estimated towards the hours of maximum fire activity (i.e., early-afternoon hours) which coincided with the MODIS/Aqua overpass. Lastly, we demonstrate the potential use of temporal metrics applied to the mid-infrared bands of MODIS and GOES data to reduce the commission errors found with the validation analyses. 相似文献
2.
Christophe Fiter Laurentiu Hetel Wilfrid Perruquetti Jean-Pierre Richard 《Automatica》2012,48(8):1860-1867
In this work, a new state-dependent sampling control enlarges the sampling intervals of state feedback control. We consider the case of linear time invariant systems and guarantee the exponential stability of the system origin for a chosen decay rate. The approach is based on LMIs obtained thanks to sufficient Lyapunov–Razumikhin stability conditions and follows two steps. In the first step, we compute a Lyapunov–Razumikhin function that guarantees exponential stability for all time-varying sampling intervals up to some given bound. This value can be used as a lower-bound of the state-dependent sampling function. In a second step, an off-line computation provides a mapping from the state-space into the set of sampling intervals: the state is divided into a finite number of regions, and to each of these regions is associated an allowable upper-bound of the sampling intervals that will guarantee the global (exponential or asymptotic) stability of the system. The results are based on sufficient conditions obtained using convex polytopes. Therefore, they involve some conservatism with respect to necessary and sufficient conditions. However, at each of the two steps, an optimization on the sampling upper-bounds is proposed. The approach is illustrated with numerical examples from the literature for which the number of actuations is shown to be reduced with respect to the periodic sampling case. 相似文献
3.
Emmanuel Bernuau Andrey Polyakov Denis Efimov Wilfrid Perruquetti 《Systems & Control Letters》2013,62(12):1159-1167
Several conditions are proposed to check different robustness properties (ISS, iISS, IOSS and OSS) for generic nonlinear systems applying the weighted homogeneity concept (global or local). The advantages of this result are that, under some mild conditions, the system robustness can be established as a function of the degree of homogeneity. 相似文献
4.
5.
Stphane Grauby Amine Salhi Luis-David Patino Lopez Wilfrid Claeys Benoît Charlot Stefan Dilhaire 《Microelectronics Reliability》2008,48(2):204-211
We have studied temperature variations on two submicrometric dissipative structures with two different techniques. On one hand, we have used a thermoreflectance imaging technique which is a well-known non contact optical method to evaluate temperature variations but whose spatial resolution is limited by diffraction. On the other hand, we have used a scanning thermal microscope (SThM) to study the thermal behaviour of these small dissipative structures. We present qualitative results obtained by both methods and we compare their advantages and drawbacks in terms of calibration and spatial resolution for thermal measurements on microelectronic devices. In particular, we show how the thermoreflectance coefficient can become an advantage to enhance the image contrast and favour the spatial resolution. 相似文献
6.
The objective of this paper is the determination of the thermal properties of micrometric layers of electronic devices using a thermoreflectance probe. Unlike classical thermoreflectance methods, the main point of the method presented in this paper is to be able to quantify the heating energy (by Joule effect) and the effective temperature response (by calibration). It is then possible to estimate the thermal conductivity (in W m−1 K−1) instead of the thermal diffusivity (in m2 s−1). A semi-analytical thermal 3D-periodic model then enables to identify a few thermal properties of the layers of the device, and in particular the thermal conductivity of the passivation layer. This methodology has been applied to the study of an industrial device containing interconnect test structures made of copper lines on a silicon wafer with a few micrometers BCB (BenzoCycloButene) polymer passivation layer. The BCB thermal conductivity and the metal heat capacity are obtained using this method. 相似文献
7.
D Marchal W Boireau JM Laval J Moiroux C Bourdillon 《Canadian Metallurgical Quarterly》1998,74(4):1937-1948
The long-range diffusion coefficients of isoprenoid quinones in a model of lipid bilayer were determined by a method avoiding fluorescent probe labeling of the molecules. The quinone electron carriers were incorporated in supported dimyristoylphosphatidylcholine layers at physiological molar fractions (<3 mol%). The elaborate bilayer template contained a built-in gold electrode at which the redox molecules solubilized in the bilayer were reduced or oxidized. The lateral diffusion coefficient of a natural quinone like UQ10 or PQ9 was 2.0 +/- 0.4 x 10(-8) cm2 s(-1) at 30 degrees C, two to three times smaller than the diffusion coefficient of a lipid analog in the same artificial bilayer. The lateral mobilities of the oxidized or reduced forms could be determined separately and were found to be identical in the 4-13 pH range. For a series of isoprenoid quinones, UQ2 or PQ2 to UQ10, the diffusion coefficient exhibited a marked dependence on the length of the isoprenoid chain. The data fit very well the quantitative behavior predicted by a continuum fluid model in which the isoprenoid chains are taken as rigid particles moving in the less viscous part of the bilayer and rubbing against the more viscous layers of lipid heads. The present study supports the concept of a homogeneous pool of quinone located in the less viscous region of the bilayer. 相似文献
8.
9.
For determination of random unsaturation within the macromolecules of poly-vinyl chloride the oxidation of double bonds by potassium permanganate is used. After the cleavage of the polymer with potassium permanganate a remarkable decrease in molecular weight is observed. The oxidation reaction was investigated using N.N-dimethylacetamide as a solvent. From the temperature dependence of the reaction rate an activation energy of 23,9 keal/mole is calculated. A comparison of the molecular weights before and after oxidation gives the average content of double bonds within different samples, which was found for the products under investigation from 0.2 to 1.2 double bonds per 1000 carbon atoms by this method. 相似文献
10.
Berger Harold Kraska I. R. Niklas Wilfrid F. Schmidt Adolph 《IEEE transactions on nuclear science》1966,13(2):79-83
An image intensifier tube of the vacuum tube type, sensitive to thermal neutrons has been developed and tested. The tube provides a bright visible output signal for an incoming thermal neutron image. Sensitivity, resolution, speed, contrast and relative response to radiation other than thermal neutrons all appear to be adequate for application to neutron imaging studies employing either reactor or non-reactor thermal neutron sources. The above characteristics, and applications of the system, are discussed. 相似文献