Remote sensing of invasive species is a critical component of conservation and management efforts, but reliable methods for the detection of invaders have not been widely established. In Hawaiian forests, we recently found that invasive trees often have hyperspectral signatures unique from that of native trees, but mapping based on spectral reflectance properties alone is confounded by issues of canopy senescence and mortality, intra- and inter-canopy gaps and shadowing, and terrain variability. We deployed a new hybrid airborne system combining the Carnegie Airborne Observatory (CAO) small-footprint light detection and ranging (LiDAR) system with the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) to map the three-dimensional spectral and structural properties of Hawaiian forests. The CAO-AVIRIS systems and data were fully integrated using in-flight and post-flight fusion techniques, facilitating an analysis of forest canopy properties to determine the presence and abundance of three highly invasive tree species in Hawaiian rainforests.
The LiDAR sub-system was used to model forest canopy height and top-of-canopy surfaces; these structural data allowed for automated masking of forest gaps, intra- and inter-canopy shadows, and minimum vegetation height in the AVIRIS images. The remaining sunlit canopy spectra were analyzed using spatially-constrained spectral mixture analysis. The results of the combined LiDAR-spectroscopic analysis highlighted the location and fractional abundance of each invasive tree species throughout the rainforest sites. Field validation studies demonstrated < 6.8% and < 18.6% error rates in the detection of invasive tree species at 7 m2 and 2 m2 minimum canopy cover thresholds. Our results show that full integration of imaging spectroscopy and LiDAR measurements provides enormous flexibility and analytical potential for studies of terrestrial ecosystems and the species contained within them. 相似文献
In occupational safety and health, big data and analytics show promise for the prediction and prevention of workplace injuries. Advances in computing power and analytical methods have allowed companies to reveal insights from the “big” data that previously would have gone undetected. Despite the promise, occupational safety has lagged behind other industries, such as supply chain management and healthcare, in terms of exploiting the potential of analytics and much of the data collected by organizations goes unanalyzed. The purpose of the present paper is to argue for the broader application of establishment-level safety analytics. This is accomplished by defining the terms, describing previous research, outlining the necessary components required, and describing knowledge gaps and future directions. The knowledge gaps and future directions for research in establishment-level analytics are categorized into readiness for analytics, analytics methods, technology integration, data culture, and impact of analytics. 相似文献
Herein a useful methodology to synthesize the lead zirconate titanate (PZT) nanotubes via a dip-coating deposition process with anodic aluminum oxide (AAO) template is proposed. The nano-porous AAO templates were produced using a controlled two-step electrochemical anodization technique. The PZT/AAO composite was formed using the dip-coating wetting technique. The prepared PZT precursor solution was driven into the nanopore channels of AAO template under the driving force of capillary action, subsequently the sintering process of the as-filled templates was carefully tuned to obtain Pb(Zr0.52Ti0.48)O3 nanotubes of crystalline tetragonal phase with uniform pore size and ordered arrange. Fourier transform infrared spectroscopy (FTIR) results show that in the 1200–1900 cm−1 band, the composite structure of PZT/AAO has obvious absorption peaks at 1471.56 cm−1 and 1556.09 cm−1, the absorption intensity of the composite structure is about six times of pure AAO template. The unusual optical properties found in PZT/AAO composite will stimulate further theoretical and experimental interests in ferroelectric nanostructures. 相似文献
People who are totally blind or who have vevere visual impairments (e.g. less than 20/200 acuity, central macular scotomas, or advanced diabetic retinopathy) see the environment in a fashion that may be completely foreign to those who operate in a very visual fashion. For this population, the visual complexity of the environment is not a concern. What is of concern are salient features found within the environment that relate to their ability to navigate successfully in, and/or interact with, the environment as needed. Toward the purpose of representing these salient features in comprehensive form, investigators at the Atlanta Veterans Affairs Research and Development Center are employing wearable computer technology to develop a virtual environment interface. The long-range goal is to create a simplistic virtual representation of the environment that includes only features related to the current navigational task and/or interactive needs of the person. In a completed study, the use of digital infrared transmitters as beacons representing salient features of the environment was explored. The purpose of a current study now in progress is to evaluate and compare various user interface structures that were suggested by subjects during the preliminary study. The problem of interest in the current study is street-crossing; however, the results of this research should be applicable to many other problems, including identifying and locating building entrances, and identifying, locating and interacting with electronic devices such as information kiosks, automated teller machines, and self-serve point-of-sale terminals. The long-range result desired is a wearable computer with which one can easily identify and interact with a wide variety of devices in the environment via one familiar, easy-to-use interface. 相似文献