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251.
A generalized approach for producing,quantifying, and validating citizen science data from wildlife images 总被引:1,自引:0,他引:1
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Alexandra Swanson Margaret Kosmala Chris Lintott Craig Packer 《Conservation biology》2016,30(3):520-531
Citizen science has the potential to expand the scope and scale of research in ecology and conservation, but many professional researchers remain skeptical of data produced by nonexperts. We devised an approach for producing accurate, reliable data from untrained, nonexpert volunteers. On the citizen science website www.snapshotserengeti.org , more than 28,000 volunteers classified 1.51 million images taken in a large‐scale camera‐trap survey in Serengeti National Park, Tanzania. Each image was circulated to, on average, 27 volunteers, and their classifications were aggregated using a simple plurality algorithm. We validated the aggregated answers against a data set of 3829 images verified by experts and calculated 3 certainty metrics—level of agreement among classifications (evenness), fraction of classifications supporting the aggregated answer (fraction support), and fraction of classifiers who reported “nothing here” for an image that was ultimately classified as containing an animal (fraction blank)—to measure confidence that an aggregated answer was correct. Overall, aggregated volunteer answers agreed with the expert‐verified data on 98% of images, but accuracy differed by species commonness such that rare species had higher rates of false positives and false negatives. Easily calculated analysis of variance and post‐hoc Tukey tests indicated that the certainty metrics were significant indicators of whether each image was correctly classified or classifiable. Thus, the certainty metrics can be used to identify images for expert review. Bootstrapping analyses further indicated that 90% of images were correctly classified with just 5 volunteers per image. Species classifications based on the plurality vote of multiple citizen scientists can provide a reliable foundation for large‐scale monitoring of African wildlife. 相似文献
252.
大气污染物排放清单是了解大气污染特征和控制对策的前提。根据排放因子方法,建立了2018年西宁市金属(包括黑色和有色金属)冶炼和压延加工业PM2.5、PM10大气污染物的排放清单,并对其时空分布特征和清单不确定性进行了分析。结果表明:西宁市黑色金属冶炼和压延加工业PM2.5、PM10的总排放量分别是4.88×103、8.37×103 t;该行业对PM2.5、PM10排放量贡献率最大的是城北区,分别为58.36%、49.61%。有色金属冶炼和压延加工业PM2.5、PM10的总排放量分别是1.85×103、2.78×103 t,该行业对PM2.5、PM10贡献率最大的是大通县,分别为53.51%、56.99%。黑色金属冶炼和压延加工业对PM2.5、PM10贡献率最大的产业是粗钢产业,贡献率分别是38.41%、30.28%。有色金属冶炼和压延加工业对PM2.5、PM10贡献率最大的是铝行业,贡献率分别是97.33%和98.01%。2个行业PM2.5和PM10的排放受月份影响较小,一天中09:00—18:00是排放高峰期。蒙特卡罗法模拟结果表明:黑色金属冶炼和压延加工业95%置信区间的不确定性较高,PM2.5和PM10的不确定性分别为-59.33%~58.55%和-47.51%~47.28%。 相似文献
253.
小波变换理论在炸药装药安全性检验中的应用 总被引:1,自引:0,他引:1
工业CT探测炸药时,存在的严重噪声使得信号难以识别,严重影响了炸药探测的可靠度和精确度.为提高工业CT探测炸药的信噪比和可靠性,利用小波变换的方法降低信号噪声以实现有效的炸药探测.结果显示,小波变换可以实际地进行工业CT探测炸药得到的信号的分析,能有效地抑制噪声和提高信噪比,并且利用小波变换可以检测出药柱的裂纹以及裂纹的位置. 相似文献
254.
机器振动对厂房结构影响的检测及分析 总被引:5,自引:0,他引:5
应用振动测试方法,对机器振动对厂房结构的影响进行检测及分析.检测结果分析表明,在机器振动产生的动荷载作用下,厂房结构振动响应不满足工程结构安全要求.分析了其原因并提出应采取的有效措施,为对厂房结构进行安全评价提供了可靠的科学依据. 相似文献
255.
非稳定流巷道火灾试验系统的研制 总被引:4,自引:1,他引:3
介绍了巷道火灾试验系统的构成,测定燃烧区膨胀热阻时测点位置的确定方法,火灾时期烟气温度、壁温及岩体温度、烟流中CO2及O2体积分数、沿程压力和风速等的测试方法及测试仪表精度,系统抗干扰方法,数据采集和处理软件的功能以及测试系统的调试方法.系统采用无补偿导线经济地解决了巷道燃烧区测温热电偶冷端温度补偿的方法,使测温系统误差由过去的10%左右下降到3%. 相似文献
256.
Bioabsorbable soy protein plastic composites: Effect of polyphosphate fillers on water absorption and mechanical properties 总被引:7,自引:0,他引:7
The use of synthetic and natural bioabsorbable plastics has been severely limited due to their low stiffness and strength
properties as well as their strong tendency to absorb moisture. This research focused on the development of bioabsorbable
polyphosphate filler/soy protein plastic composites with enhanced stiffness, strength, and water resistance. Bioabsorbable
polyphosphate fillers, biodegradable soy protein isolate, plasticizer, and adhesion promoter were homogenized and compression-molded.
Physical, mechanical, and water absorption testing was performed on the molded specimens. Results showed improvements in stiffness,
strength, and water resistance with increasing polyphosphate filler content up to 20% by weight. Application of a coupling
agent produced further mechanical property enhancements and a dramatic improvement in water resistance, interpreted by an
interfacial chemical bonding model. Examination of the fracture surfaces of the materials revealed that the addition of the
polyphosphate fillers changed the failure mode from brittle to pseudo-ductile. These results suggest that these materials
are suitable for many load-bearing applications in both humid and dry environments where current soy protein plastics are
not usable. 相似文献
257.
Review of konjac glucomannan 总被引:5,自引:0,他引:5
The paper reviews the solution and gelling properties of konjac glucomannan (KGM) and its interactions with other hydrocolloids
such as xanthan and carrageenan for food applications. Research activities in the area of KGM processing in environmentally
friendly aqueous environments have been discussed for coatings and packaging applications.
Guest Editor: Heidi Schreuder-Gibson, U.S. Army Natick RD&E Center, Kansas Street, Natick, Massachusetts 01760-5020 相似文献
258.
本文系统地介绍了极轨气象卫星及其区域性遥感资料处理系统。分析探讨了NOAA/AVHRR资料在四川省各非气象领域应用的可能性。 相似文献
259.
Morris Deutsch F. H. Ruggles 《Journal of the American Water Resources Association》1978,14(2):261-274
ABSTRACT: During August and September 1973, the Indus River Valley of Pakistan experienced one of the largest floods on record, resulting in damages to homes, businesses, public works, and crops amounting to millions of rupees. Tremendous areas of lowlands were inundated along the Indus River and major tributaries. Landsat data made it possible to easily measure the extent of flooding, totaling about 20,000 km2 within an area of about 400,000 km2 south from the Punjab to the Arabian Sea. The Indus River data were used to continue experimentation in the development of rapid, accurate, and inexpensive optical techniques of flood mapping by satellite begun in 1973 for the Mississipi River floods. The research work on the Indus River not resulted in the development of more effective procedures for optical processing of flood data and synoptically depicting flooding, but also provided potentially valuable ancillary information concerning the hydrology of much of the Indus River Basin. 相似文献
260.
Robert C. Ward David A. Link William M. Crosswhite 《Journal of the American Water Resources Association》1972,8(3):495-504
ABSTRACT This paper summarizes a study employing a systems approach for analyzing one class of modifications within a poultry processing plant. The modifications considered were changes in water-flow arrangements and process characteristics to reduce water intake of the plant and waste-treatment costs. The object of the study was to develop a technique or techniques by which a combination of proposed modifications could be chosen to minimize water flow through the plant. Existing and proposed flows were represented as a network, and linear programming was used to solve the minimum-flow problem for the network. Application of the technique was made to an existing, typical plant in Durham, N.C. Results of the application showed fresh water intake could be reduced by 45% to 51%, and furthermore that annual returns of 62% to 494% could be obtained on investment in the optimum modification sets, as fresh water costs varying from 10 cents to $1.00 per 1000 gal. Types of modifications of a poultry processing plant are classified by types, and the relative importance and effectiveness of each type are discussed. 相似文献