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Nano-mirror embedded back reflector layer (BRL) for advanced light management in thin silicon solar cells
摘要： This work illustrates a technology for advanced light management by introducing a nonconventional back reflector layer (BRL) in amorphous silicon (a-Si:H) solar cells. To meet this, silver sulfide (Ag2S) nanoparticles with ~50 nm diameter have been chosen as the nano-mirror owing to its low parasitic absorption loss over a broad wavelength (300 to 1100 nm) region. The Ag2S NPs were sandwiched between two indium tin oxide (ITO) layer and placed as the back reflector layer of an a-Si:H solar cell to achieve better light trapping within the active layers. The embedded structure exhibited high reflectance (up to 93%) in the red and near-infrared region, the main working zone of a-Si:H cells. With the incorporation of such state of the art back reflector structure in a-Si:H solar cells, a photo-conversion efficiency of 10.58% has been achieved; which is one of the best in this class.
关键词： a-Si:H solar cell,Back reflection,theoretical validation,high efficiency,nano-mirror
更新于2025-11-21 11:01:37
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Results from the validation campaign of the ozone radiometer GROMOS-C at the NDACC station of La Réunion Island
摘要： Ozone is a species of primary interest as it performs a key role in the middle atmosphere and its monitoring is thus necessary. At the Institute of Applied Physics of the University of Bern, Switzerland, we built a new ground based microwave radiometer, GROMOS-C (GRound based Ozone MOnitoring System for Campaigns). It has a compact design and can be operated at remote places with very little maintenance requirements, being therefore suitable for remote deployments. It has been conceived to measure the vertical distribution of ozone in the middle atmosphere, by observing pressure broadened emission spectra at a frequency of 110.836 GHz. In addition, meridional and zonal wind profiles can be retrieved, based on the Doppler shift of the ozone line measured in the 4 directions of observation (North-East-South-West). In June 2014 the radiometer was installed in the Ma?do observatory, on La Réunion Island (21.2°S, 55.5°E). High resolution ozone spectra were continuously recorded during 7 months. Vertical profiles of ozone have been retrieved through an optimal estimation inversion process, using the Atmospheric Radiative Transfer Simulator ARTS2 as the forward model. The best estimate of the vertical profile is done by means of the optimal estimation method. The validation is performed against ozone profiles from the Microwave Limb Sounder (MLS) on the Aura satellite, the ozone lidar located in the observatory and with ozone profiles from weekly radiosondes. Zonal and meridional winds retrieved from GROMOS-C data are validated against another wind radiometer located in situ, WIRA. In addition, we compare both ozone and winds with ECMWF model data. Results show that GROMOS-C provides reliable ozone profiles between 30 to 0.02 hPa. The comparison with lidar shows a very good agreement at all levels. The accordance with MLS is within less than 10% for pressure levels between 25 and 0.2 hPa.
关键词： ozone,validation,wind profiles,microwave radiometer,middle atmosphere,GROMOS-C
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - LaSRC (Land Surface Reflectance Code): Overview, application and validation using MODIS, VIIRS, LANDSAT and Sentinel 2 data's
摘要： This paper presents a generic approach developed to derive surface reflectance over land from a variety of sensors. This technique builds on the extensive dataset acquired by the Terra platform by combining MODIS and MISR to derive an explicit and dynamic map of band ratio’s between blue and red channels and is a refinement of the operational approach used for MODIS and LANDSAT over the past 15 years. We will present the generic approach and the application to MODIS VIIRS, LANDSAT and Sentinel 2 data’s and its validation using the AERONET data [1].
关键词： aerosol,surface reflectance,validation
更新于2025-09-23 15:23:52
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LEFMIS: locally-oriented evaluation framework for medical image segmentation algorithms
摘要： This article proposes a novel framework for the locally-oriented evaluation of segmentation algorithms (LEFMIS). The presented approach is robust and takes into account local inter/intra-observer variability and the anisotropy of medical images. What is more, the framework makes it possible to distinguish types of error locally. These features are crucial in the context of cancer image data. The proposed framework is based on use of the signed anisotropic Euclidean distance transform and the distance projection. It can be used easily in many different applications with or without additional expert outlines (both inter- and intra-observer variability). The performance of the proposed framework is depicted using both artificial and kidney cancer CT data with experts’ manual outlines. In the article, in the case of artificial data, it is presented that the manual outlines dispersion is symmetric in relation to the truth border. The effectiveness of the selected segmentation algorithm was analysed in the context of kidney cancer using computed tomography data. For the calculated local inter-observer variability, 80.11% of the surface points generated by the kidney segmentation algorithm are within one expert outline standard deviation and 97.96% are within five. An error distribution shift in the direction of type I error equivalent was also observed. Finally, the significance of the local estimation of error type differences is presented. The article shows the greater usefulness and flexibility of the proposed framework in comparison to the state-of-the-art methods. The exemplary usage of the LEFMIS with or without inter-/intra-observer variability is also presented.
关键词： evaluation,validation,cancer images,intraobserver variability,kidney segmentation,interobserver variability,error types
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Validation of Wave and Wind Product of the New Phase Saral Using Buoys Data
摘要： Since July 4th 2016, the SARAL/Altika has been moved in a new orbit, and it has continuously provided wave height measurements for more than 1 year. Before using these data, the measurements need to be validated. Based on the in-situ buoys from the National Data Buoy Center (NDBC), the SARAL Ka-band significant wave height (SWH) and Sea Surface Wind (SSW) measurements were validated and have been corrected using a linear regression with in-situ measurements. Compared with NDBC data, the validation results of SARAL show a RMS (Root Mean Square) of 0.28 m for SARAL SWH measurements and RMS of 1.30m/s for SARAL SSW speed indicating capability of AltiKa providing SWH and wind speed products with reliable accuracy. Therefore the accuracy of SARAL SWH products is higher than that of Jason-1/2 SWH data, and does not require any correction.
关键词： Sea Surface Wind,SARAL/AltiKa,Validation,Root Mean Square,Significant Wave Height
更新于2025-09-23 15:22:29
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Validation of MODIS-Aqua bio-optical algorithms for phytoplankton absorption coefficient measurement in optically complex waters of El Rincón (Argentina)
摘要： El Rincón is a highly productive area in the inner-shelf of the Argentine Sea, southern Buenos Aires Province (39°S–62.5°W; 41.5°S–60°W), regarded as the habitat for commercially valuable ?sh species and important for local artisanal ?sheries. The aims of this work were to characterize for the ?rst time the in situ absorption coe?cient of phytoplankton (aph(λ)) in relation to phytoplankton composition and chlorophyll-a (Chl-a) concentration, and to evaluate the satellite retrieval of aph(443) using two atmospheric correction algorithms and three bio-optical semi-analytical algorithms in order to de?ne which is more suitable for the study area. A total of 28 oceanographic cruises were performed between November 2013 and March 2017 and the sampling included physical variables (temperature, salinity, suspended particulate matter, SPM), Chl-a, phytoplankton absorption and composition. The phytoplankton community was mainly dominated by chain-forming diatoms from the microplankton size class (40–80%), while a single coccolithophore, Gephyrocapsa oceanica (cell diameter < 10 μm) was a key component (up to 40%) of the nanoplankon. In situ Chl-a (mean 1.8 mg m?3) and aph(443) (mean 0.052 m?1) generally covariated with no clear seasonality. Their correlation was rather low (R2 = 0.52) and with high scattering, in agreement with the high interannual variability of phytoplankton composition. Further, the relative low mean speci?c absorption coe?cient of phytoplankton (aph*(443), 0.032 m2 (mg Chl-a)?1) and (aph*(676), 0.014 m2 (mg Chl-a)?1) denoted the presence of big cells and pigment packaging e?ect. Aside from the optical complexity of these waters, reasonable results were found using the Quasi Analytical Algorithm in retrieving aph coe?cient (R2 = 0.55, Bias = 19%) and switching the atmospheric correction algorithm depending on the distance to the coast, the depth and turbidity. The results found in this paper present for the ?rst time the phytoplankton composition and absorption of algal material characteristics and the derived implication on the performance of bio-optical algorithms in the optically complex waters of El Rincon.
关键词： Absorption by phytoplankton,Bio-optical algorithms,Turbid coastal waters,Phytoplankton composition,Validation,MODIS-Aqua
更新于2025-09-23 15:22:29
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Applicability of near infrared spectroscopy for real-time soil detection during automatic dishwashing
摘要： The purpose of this study was to utilize NIR spectrometry to develop a novel method to detect and determine concentrations of different soils in dishwashing liquor during automatic dishwashing in real-time. If it is possible to differentiate between soils, this could be an opportunity to react specifically to them (e.g. by increasing the water temperature if fat components are not sufficiently emulsifying). The possibility of an automatic adaptation of the dishwashing process to different soils and soil levels could lead to a shorter, more environmentally friendly and cost-reducing process. In a first approach, an emulsion containing three soil types (oatmeal, egg-yolk and butterfat), water and detergent were used to develop NIR spectrometry prediction models. Transmittance spectra obtained with an Fourier transform near infrared (FT-NIR) spectrometer of testing standards of 76 automatic dishwashing cycles with seven samples per cycle were taken at various times during the main washing process for calibration (and validation) of the NIR spectrometry prediction models. The spectra were pretreated to develop NIR spectrometry prediction models for each type of soil using the partial least squares regression method with cross-validation. Overall, the coefficients of determination in cross-validation are R2 > 0.92 for all NIR spectrometry prediction models developed. The results of the prediction models developed show that NIR spectrometry technology is a promising method to predict different levels of predefined soils in dishwashing liquor. The NIR spectrometry models were applied to an automatic dishwashing process with soiled dishes instead of emulsions containing soils to test their applicability. The resulting dishwashing process could be tracked in real-time by the dissolved soil concentrations, observed in the dishwashing liquor.
关键词： dishwasher,validation,sensor,emulsion,calibration,homogenization,soil,Near infrared spectroscopy
更新于2025-09-23 15:22:29
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A new TRNSYS type for thermosiphon flat-plate solar thermal collectors: validation and optimization procedure
摘要： This paper presents a new TRNSYS Type (called Type 99) which can be used for the energy assessment of thermosiphon Flat-Plate solar thermal Collectors (FPCs) for water heating. The accuracy of this new type is higher than the standard type (Type 45a) available in TRNSYS library, since the density and specific heat of water are estimated according to the operating fluid temperature. The results of a suitable experimental campaign are also presented for different commercial FPCs system layouts. The developed Type 99 is successfully validated, proven by the very good agreement achieved between the simulation and experimental results. By the new Type 99 a suitable Design of Experiment (DoE) analysis is carried out with the aim to assess the design and operating parameters mostly affecting the energy and economic performance of two types of FPCs. Specifically, collector pipe diameters, slope, storage tank volume, and thermal insulation thickness are investigated. The analysis is carried out for three case studies which refer to residential Domestic Hot Water (DHW) production applications and to three different European weather zones (Freiburg, Naples and Larnaca). For these case studies an optimization procedure is also carried out by varying the same design and operating parameters for two different objective functions: best energy behaviour [maximum Primary Energy Saving (PES)] and best economic performance [minimum Simple Pay Back (SPB)]. Interesting novel design criteria and encouraging economic results are obtained.
关键词： economic assessment,DoE analysis,Building solar thermal systems,dynamic energy performance analysis,experimental validation
更新于2025-09-23 15:22:29
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Hyperspectral signature analysis using neural network for grade estimation of copper ore
摘要： The ever-increasing demand for the different metal and mineral resources from the earth’s subsurface has brought tremendous pressure on the geochemical laboratory for the growing countries. The success of any mining industry relies on the estimated values of ore grade in the mineral deposit. Hence, rapid assessment of ore grade is critical in daily schedule in mines operations. Commonly the assay value is determined by chemical analysis or X-Ray Fluorescence (XRF), which is one of the constrained by real-time grade estimation, duration of sample preparation and processing. Several researches carried out in exploration and revealed that hyperspectral technique is a promising tool for mineral identification and mapping. The goal of the present study is to determine the effectiveness of narrow band spectroscopy in Cu grade estimation. To achieve this, a multilayer feed-forward neural network model has been developed to establish a functional link between hyperspectral signature derived features with the copper grade. Altogether eight different types of features including absorption depth, band depth center, the area under the absorption curve, full width at half maxima were extracted from continuum removed spectra along with derivative reflectance features, e.g. band depth ratio, 1st and 2nd slopes from the hyperspectral profile. The dimensionality was reduced by applying Principal Component Analysis onto the extracted features. The first seven PCAs are then used as input vector of the ANN model. A five-fold cross-validation exercise is carried out for model performance. The high degree of correlation reveals that the PCA generated feature from hyperspectral data coupled with ANN model could be an alternative approach to predict the copper grade for the copper mine.
关键词： copper grade,ore grade estimation,spectral feature,K-Fold cross validation,principal component analysis,artificial neural network
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Retrieval and Validation of Sea Ice Concentration from AMSR-E/AMSR2 in Polar Regions
摘要： Sea ice concentration (SIC) is an important sea ice parameter of the atmosphere-ice-ocean system in the polar region. Daily 6.25 km AMSR-E/AMSR2 SIC from Bremen University (UB) is one of the widely used SIC products. In this paper, MODIS data and aerial image are used to validate this product. The results show that the daily mean AMSR-E ASI products underestimate SICs about 17.9% based on the aerial image, and underestimate SICs about8.5% based on MODIS image. The sea ice extent (SIE) and sea ice area (SIA) which are derived from SIC by ASI algorithm, Dynamic Tie-point ASI algorithm (DT-ASI) as well as NT algorithm are compared.
关键词： Retrieval,Validation,aerial image,Sea ice concentration,AMSR-E,MODIS
更新于2025-09-23 15:22:29