The influence of epiphylls on remote sensing of humid forests

Epiphylls - lichens, fungi, liverworts, etc. infesting leaf surfaces - are found throughout humid forests of the world. It is well understood that epiphylls inhibit light interception by host plants, but their effect on remote sensing of colonized forests has not been examined. Incorporating leaf-level spectra from Terra Firme (primary forest) and Amazonian Caatinga (woodlands/forest growing on nutrient-deficient sandy soils), we used the GeoSAIL model to propagate leaf-level measurements to the canopy level and determine their effect on commonly used vegetation indices. In Caatinga, moderate infestations (50% leaf area epiphyll cover), lowered simulated Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) values by 6.1% and 20.4%, respectively, largely due to near infrared dampening. Heavy infestation (100% cover) simulations exhibited decreases 1.5-2 times greater than those of moderate infestations. For Terra Firme, which are generally less affected by epiphylls, moderate (20% leaf area) and heavy infestations (40%) lowered EVI by 4.4% (S.D. 0.8%) and 8.1% (S.D. 1.5%), respectively. Near infrared and green reflectance were most affected at the canopy level, showing mean decreases of 10.6% (S.D. 2.25%) and 9.5% (S.D. 3.49%), respectively, in heavy Terra Firme infestations. Time series of Moderate Resolution Imaging Spectrometer (MODIS) data corroborated the modeling results, suggesting a degree of coupling between epiphyll cover and the EVI and NDVI. These results suggest that, without explicit consideration of the presence of epiphylls, remote sensing-based methodologies may underestimate leaf area index, biomass and productivity in humid forests.     

NASA EOS Terra ASTER: Volcanic topographic mapping and capability

Up-to-date, accurate topographic data are a crucial resource for volcanic research and risk mitigation efforts, in particular, for modeling volcanic flow processes at a detailed spatial resolution. In this paper, we examine the utility of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument currently operating on the NASA Terra satellite, which provides near infrared (VNIR) stereo imaging from which topography can be derived. We wrote software to generate digital elevation models (DEMs) from the ASTER level 1A product, which employs an automated stereo matching technique to calculate the parallax offsets between the images acquired by the nadir- and aft-looking sensors. Comparison of ASTER DEMs with DEMs derived from other sources (digitized 1:50 K topographic maps and aerial interferometric radar) at Ruapehu volcano reveal an RMS error of about 10 m for the ASTER DEM, in the absence of significant atmospheric water vapor. A qualitative assessment of surface features showed that the ASTER DEM is superior to the interpolated 1:50 K map product but falls short of the detail provided by aerial interferometric radar, especially in terms of stream channel preservation. A second ASTER DEM was generated for Taranaki volcano, where previously only 1:50 K topographic map data were available. Although the 2000 Space Shuttle radar topography mission (SRTM) will largely remedy the previous global paucity of adequate topographic data at volcanoes, such as Taranaki, we anticipate the problem that at active volcanoes, the topography may change significantly following activity, rendering the SRTM data inaccurate. With the high temporal coverage of the dataset, ASTER not only provides a means to update significant (>10 m) topographic measurements at active volcanoes via a time-series of DEMs, but also provides a simultaneous means to map surface cover and localized land-use via the near infrared sensors. Thus we demonstrate the potential for up-to-date volcanic economic risk assessment using geographic information systems (GIS) analysis.     

岩石力学三轴应力测试系统及其应用

三轴应力测试系统可以模拟井下状态，对岩样进行力学、声学、变形、破碎等各种应力特性进行系统的测量。本文详细介绍了该系统的组成、功能及其测量参数在油气钻井与开发工程等工业领域的应用。     

Making Bibelot: Casting material research within cultural frameworks

Material investigations in architecture often exclude practice implications by narrowly determining the scope and limitations of research. Such limitations are necessary and warranted for open-ended inquiries undertaken in controlled conditions. Working with commercial outfits in the context of a prescribed project, on the other hand, requires a clear attitude that accounts for the agency of the manufacturer. A small design-build intervention, completed with an in-kind donation from a terra cotta manufacturer in Buffalo, New York, gave us the opportunity to take on such a collaborative investigation. In order to explore the potentials of terra cotta as a building material to the greatest extent, we strategically increased the complexity of the endeavor, challenging the design and manufacturing team to address production problems in a timely manner to meet the project goals. In doing this, we relied on conceptual constructs that address specific material and institutional histories of terra cotta and the cultural context, registered as form, color, and ornamentation in the project. The paper gives a detailed account of the entire process and the working assumptions by bridging the design and manufacturing decisions in an interrelated manner.     

Distinguishing Between the Drawn and the Made

Here Bob Sheil , Director of Technology and Computing at the Bartlett School of Architecture and co-organiser of the 2011 Fabricate Conference at UCL, pulls back on the rush towards material computation. With the blurring of the projected image and the constructed artefact, there is the very real danger of reducing ‘architectural production to a systematic industrial exercise’. This fails to recognise the extent to which ideas and performance are transformed, developed and refined through the very process of making. Copyright © 2012 John Wiley & Sons, Ltd.     

3D打印的兵马俑文创服装设计定制化服务研究

目的 研究3D打印技术在文创服装制作上的应用。方法 运用文献资料法、田野考察法及实践性研究,对3D打印服装的技术以及定制化服务的相关情况进行概述,研究3D打印在文创产业的定制化服务方面的可行性及优势。以3D打印图案的兵马俑文创服装的制作过程为例,证明了3D打印技术可以用于文创类服装的定制化生产、制作。结论 3D打印技术支撑的兵马俑文创服饰的定制化服务具有良好的发展前景,并且其技术已经成熟,是一个极有潜力的产业。     

Spectral Matching of FY-2 Series SatellitesInfrared Channels Inter-calibration

The method of spectral matching for broadband infrared channels of remote sensors was introduced in this paper.The channels of FY-2C’s IR1,IR2 and Terra/Aqua MODIS 31,32 were selected as example to do spectral matching,calculate the matching coefficients for corresponding channels.All of these efforts were set the seals on the inter calibration of two sensors.This method can be used for all kinds of infrared remote sensors corresponding channels inter calibration spectral matching and also provide a good methodology for the radiometric normalization in the different types of infrared remote sensors.This method can be used to establish the uniformed globe infrared remote sensing database.     

Spatially and temporally continuous LAI data sets based on an integrated filtering method: Examples from North America

Leaf Area Index (LAI) is an important biophysical variable for characterizing the land surface vegetation. Global LAI product has been routinely produced from the MODerate resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellite platforms. However, the MODIS standard LAI product is not continuous both spatially and temporally. To fill the gaps and improve the quality, we have developed a data filtering algorithm. This filter, called the temporal spatial filter (TSF), integrates both spatial and temporal characteristics for different plant functional types. The spatial gaps are first filled with the multi-year averages of the same day. If the values are missing over all years, the pixel is filled with a new estimate using the vegetation continuous field-ecosystem curve fitting method. The TSF integrates both the multi-seasonal average trend (background) and the seasonal observation. We implement this algorithm using the MODIS Collection 4 LAI product over North America. Comparison of the TSF results with the Savitzky-Golay filter indicates that the TSF performs much better in restoring the spatial and temporal distribution of seasonal LAI trends. The new LAI product has been validated by comparing with field measurements and the derived LAI maps from ETM+ data at a broadleaf forest site and an agricultural site. The validation results indicate that the new LAI product agrees better with both the field measurements and LAI values obtained from the ETM+ than does the MODIS LAI standard product, which usually shows higher LAI values.     

基于Terra的数字版权管理设计及实现

文章提出了一个基于Terra的数字版权保护平台的设计和原型系统并研究分析了一些应用实例。     

Monitoring on-orbit calibration stability of the Terra MODIS and Landsat 7 ETM+ sensors using pseudo-invariant test sites

The ability to detect and quantify changes in the Earth's environment depends on sensors that can provide calibrated, consistent measurements of the Earth's surface features through time. A critical step in this process is to put image data from different sensors onto a common radiometric scale. This work focuses on monitoring the long-term on-orbit calibration stability of the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) and the Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) sensors using the Committee on Earth Observation Satellites (CEOS) reference standard pseudo-invariant test sites (Libya 4, Mauritania 1/2, Algeria 3, Libya 1, and Algeria 5). These sites have been frequently used as radiometric targets because of their relatively stable surface conditions temporally. This study was performed using all cloud-free calibrated images from the Terra MODIS and the L7 ETM+ sensors, acquired from launch to December 2008. Homogeneous regions of interest (ROI) were selected in the calibrated images and the mean target statistics were derived from sensor measurements in terms of top-of-atmosphere (TOA) reflectance. For each band pair, a set of fitted coefficients (slope and offset) is provided to monitor the long-term stability over very stable pseudo-invariant test sites. The average percent differences in intercept from the long-term trends obtained from the ETM + TOA reflectance estimates relative to the MODIS for all the CEOS reference standard test sites range from 2.5% to 15%. This gives an estimate of the collective differences due to the Relative Spectral Response (RSR) characteristics of each sensor, bi-directional reflectance distribution function (BRDF), spectral signature of the ground target, and atmospheric composition. The lifetime TOA reflectance trends from both sensors over 10 years are extremely stable, changing by no more than 0.4% per year in its TOA reflectance over the CEOS reference standard test sites.