Biomass has a direct relationship with agricultural production and may help to predict crop yield. Earth observation technology can contribute significantly to monitoring given the availability of temporally frequent and high-resolution radar or optical satellite data. Polarimetric Synthetic Aperture Radar (PolSAR) has several advantages for operational monitoring given that at these longer wavelengths atmospheric and illumination conditions do not affect acquisitions and considering the sensitivity of microwaves to the structural properties of targets. Therefore, SARs are a promising source of data for crop mapping and monitoring. With increasing access to SARs the development of robust methods to monitor crop productivity is timely.
In this paper, we examine the use of machine learning and artificial intelligence approaches to analyze a time series of Polarimetric parameters for crop biomass estimation. In total, 14 polarimetric parameters from a time series of Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne L-band data were used for biomass estimation for an intensively cropped site in western Canada. Then, Multiple linear regression (MR) and artificial neural network (ANN) models were developed and evaluated to estimate the biomass for canola, corn, and soybeans. According to the experimental results, the ANN provided more accurate biomass estimates compared to MR.
Canola biomass, in general, showed less sensibility to almost all the polarimetric parameters. Nevertheless, Freeman-Double combined with vertical-vertical backscattering (VV) delivered the correlation coefficient (r) of 0.72, and the root mean square error (RMSE) of 56.55 g m?2of canola biomass. For corn, the highest correlation was observed between a pairing of horizontal- horizontal backscattering (HH) with Entropy (H) for biomass estimation yielding an r of 0.92 and RMSE of 196.71 g m?2. Horizontal-vertical backscattering (HV) and Yamaguchi-Surface (OY) delivered the highest sensitivity for soybeans (r of 0.82 and RMSE of 13.48 g m?2). If all crops are pooled, H combined with OY provided the most accurate estimates of biomass (r of 0.89 and RMSE of 135.31 g m?2). These results demonstrated that models which make use of polarimetric parameters that characterize the multiple sources of scattering typical of vegetation canopies can be used to estimate crop biomass accurately. Such results bode well for agricultural monitoring considering the increasing number of satellite SAR sensors with various frequencies, imaging modes and revisit times. As such, the time series analysis and methods proposed in this study could be used to monitor crop development and productivity using SAR space technologies. 相似文献
This paper proposes a methodology for developing earthquake‐resilient structures (ERSs). This is achieved by following principles of full cycle performance control and embracing a holistic approach to design led analysis (DLA) of ERS. Collapse prevention (CP) and postearthquake realignment and repairs (PERRs) are the basic traits of ERS. Despite the availability of several systems involving combinations of gap opening link beams (GOLBs), rigid rocking cores, buckling‐restrained braces, replaceable energy dissipating moment connections, and so forth, neither CP nor PERR are addressed in any code of practice. Although most of these devices have passed several tests of experiments and time–history analysis they have rarely been examined as integral parts of actual buildings. Real buildings cannot be ideally recentered unless specifically designed and detailed for CP and PERR. Almost all simple beam–column joints, especially standard hinged supports absorb small but sufficient amounts of residual strains that hinder PERR. The proposed methodology is introduced by way of developing an earthquake‐resilient rocking core‐moment frame, as the lateral resisting component of a gravity resisting structure that has been detailed not to develop residual effects while sustaining large lateral deformations. 相似文献
Water Resources Management - Curve number (CN) is a principal factor which is widely used in hydrology, specifically in the rainfall-runoff modelling. Its value varies based on soil moisture... 相似文献
Pattern Analysis and Applications - Probably, the most reputed solution for partitioning, which has applications in databases, attribute partitioning, processor-based assignment and many other... 相似文献
Scientometrics - Open access academic achievements include not only papers and journals, but also books, which have become an important achievement for scholars and can be regarded as scholarly... 相似文献
The hydrodynamics of a bubbling gas-solid fluidized bed of 57.4 μm FCC particles was simulated by using a state-of-the-art
two-fluid model integrating the kinetic theory of granular flow for particulate phase stresses. The overestimation of the
bed expansion was resolved by using a suitable scale factor in the drag model as suggested by McKeen and Pugsley (T.R. McKeen,
T.S. Pugsley, Powder Technol., 129, 139 (2003)). This study showed that the method was appropriate in simulation of a gas-solid
fluidized bed of Geldart A particles at high gas velocities (0.3 to 0.61 m/s). The reduction of computational time especially
for simulation of large-scale systems was achieved. The time-averaged local voidage was compared with the experimental data
and the trend of varying several parameters on the hydrodynamic of the bed was investigated. The simulation results showed
both qualitative and quantitative agreement with the literature. 相似文献
In this study, antimicrobial packaging films were prepared by coating silver (Ag) nanoparticles onto the surface of low density polyethylene (LDPE) films modified by corona air plasma. The possibility of these films for use in the packaging of milk was studied. The influence of input power of the corona discharge treatment on the surface modification and performance of the fabricated Ag/LDPE nanocomposite films was also investigated. The prepared antimicrobial packaging films showed promising antimicrobial efficiency against micro‐organisms that are present in milk and were able to increase the microbial shelf life of the milk. Packages fabricated at corona input powers of 210, 500 and 800 W reached the maximum limit after 5, 8 and 14 days (respectively). 相似文献
Exponential growth in the usage of “cytokines” (as seroimmunobiomarkers) has facilitated more accurate prognosis, early diagnosis, novel, and efficient immunotherapeutics. Numerous studies have reported immunopathophysiological and immunopathological processes of interleukin-38 (IL-38). Therefore, in this systematic review article, the authors aimed to present an updated comprehensive overview on the immunobiological mechanisms, diagnostic, and immune gene-based therapeutic potentials of IL-38. According to our inclusion and exclusion criteria, a total of 216 articles were collected from several search engines and databases from the January 2012 to July 2021 time interval by using six main keywords. Physiologic or pathologic microenvironments, optimal dosage, and involved receptors affect the functionalities of IL-38. Alterations in serum levels of IL-38 play a major role in the immunopathogenesis of a wide array of immune-mediated disorders. IL-38 shows anti-inflammatory activities by reduction or inhibition of pro-inflammatory cytokines, supporting the therapeutic aspects of IL-38 in inflammatory autoimmune diseases. According to the importance of pre-clinical studies, it seems that manipulation of the immune system by immunomodulatory properties of IL-38 can increase the accuracy of diagnosis, and decipher optimal clinical outcomes. To promote our knowledge, more collaboration is highly recommended among laboratory scientists, internal/infectious diseases specialists, oncologists, immunologists, diseases-specific biomarkers scientists, and basic medical researchers. 相似文献
Iranian Polymer Journal - The effects of two different solvents of dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP) were investigated on the properties and performance of the neat and... 相似文献
AbstractA drying technique using a combination of high power airborne ultrasound, microwaves and hot air was applied to investigate the effect of intermittent drying on the process kinetics and several quality indicators of red beetroot. An innovative hybrid dryer was used in drying experiments. Six sets of drying programs were carried out. Ultrasound and microwaves were applied in convective drying continuously (hybrid processes) or periodically (hybrid intermittent processes). The drying processes were assessed in terms of drying time, drying rate, and energy consumption. Moreover, the total color change, retention of natural dye (betanin), water activity, texture, and microstructure of dry product were examined. The drying kinetics was well-fitted with the use of the Midilli-Kucuk model. It was found that hybrid intermittent drying reduces the total drying time and energy consumption, enhances both the drying rate and product quality. Furthermore, it was demonstrated that the hybrid intermittent drying can serve as an alternative to traditional hot air drying that could produce a more porous, nice color, and crispy vegetable product. 相似文献