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41.
定点灭火智能消防水炮 总被引:15,自引:0,他引:15
在国家“九五”关于大空间建筑火灾消防新技术科技攻关成果的基础上 ,对数控自动定点扑救消防水炮进行了研究 ,研制出智能传感及其接口控制模块 ,并与“大空间火灾安全监测与自动定位技术”相结合 ,形成火灾探测与定点扑救相结合的主动式火灾探测灭火技术。该技术有较高的实用价值 ,对大空间建筑的火灾扑救具有重要意义 相似文献
42.
Methods that are more cost-effective and objective are needed to detect important vegetation change within acceptable error
rates. The objective of this research was to compare visual estimation to three new methods for determining vegetation cover
in the sagebrush steppe. Fourteen management units at the US Sheep Experiment Station were identified for study. In each unit,
20 data collection points were selected for measuring plant cover using visual estimation, laser-point frame (LPF), 2 m above-ground-level
(AGL) digital imagery, and 100-m AGL digital imagery. In 11 of 14 management units, determinations of vegetation cover differed
(P < 0.05). However, when combined, overall determinations of vegetation cover did not differ. Standard deviation, corrected
sums of squares, coefficient of variation, and standard error for the 100 m AGL method were half as large as for the LPF and
less than the 2-m AGL and visual estimate. For the purpose of measuring plant cover, all three new methods are as good as
or better than visual estimation for speed, standard deviation, and cost. The acquisition of a permanent image of a location
is an important advantage of the 2 and 100 m AGL methods because vegetation can be reanalyzed using improved software or to
answer different questions, and changes in vegetation over time can be more accurately determined. The reduction in cost per
sample, the increased speed of sampling, and the smaller standard deviation associated with the 100-m AGL digital imagery
are compelling arguments for adopting this vegetation sampling method. 相似文献
43.
Introduction: Digital billboards (DBs) are a competing factor for attracting drivers’ attention; evidence shows that DBs may cause crashes and vehicle conflicts because they catch drivers’ attention. Because of the complexity of a system that includes road conditions, driver features, and environmental factors, it is simply not possible to identify relationships between these factors. Thus, the present study was conducted to provide a well-organized procedure to analyze the effects of DBs on drivers’ behavior and measure factors responsible for drivers’ distraction in Babol, Iran, as a case study. Method: Corresponding data were collected through a Naturalistic Driving Study (NDS) of 78 participants when facing DBs (1,326 samples). These data were analyzed by applying structural equation modeling (SEM) to concurrently recognize relationships between endogenous and exogenous variables. Human, environmental, and road factors were determined as exogenous latent variables in a model to evaluate their influences on drivers’ distraction as an endogenous variable. Results: The results showed that road, environmental, and human factors reciprocally interact with drivers’ distraction, although the estimated coefficient of human factors was more of a factor than that of the other groups. Furthermore, younger drivers, beginner drivers, and male drivers (as human factors); night and unclear weather like a rainy day (as environmental factors); and installing DBs at complicated traffic positions like near-intersections (as road factors) were determined to be the main factors that increase the possibility of drivers’ distraction. Finally, model assessment was suggested using the goodness-of-fit indices. 相似文献
44.
Jacek Andrzej Urbanski 《Journal of Coastal Conservation》2001,7(2):155-162
A DTM (Digital Terrain Model) map and the analytical powers of GIS (Geographical Information System) were used in deterministic
and probabilistic methods for analysis of inundation of a coastal area. These methods were applied to evaluate the effects
of a rise in sea-level on the coastal zone of the Puck Lagoon (Poland) over a period of 100 years. The analysis evaluated
the following aspects: the threat to man-made objects such as buildings and roads; changes in the impact of the sea on the
coastal environment manifested as the frequency of flooding of grasslands and marshland in the coastal depression, and the
formation of a dune embankment. The analysis covered a ca. 5 km stretch of low-lying coastline, in which there are two rapidly
growing villages and a nature reserve. The study showed that a sealevel rise of 40 cm would increase the frequency of flooding
in the area and would probably cause the dune ridge vegetation to deteriorate. 相似文献
45.
Product quality-based eco-efficiency applied to digital cameras 总被引:1,自引:0,他引:1
When calculating eco-efficiency, there are considerable confusion and controversy about what the product value is and how it should be quantified. We have proposed here a quantification method for eco-efficiency that derives the ratio of the multiplication value of the product quality and the life span of a product to its whole environmental impact based on Life Cycle Assessment (LCA). In this study, product quality was used as the product value and quantified by the following three steps: (1) normalization based on a value function, (2) determination of the subjective weighting factors of the attributes, and (3) calculation of product quality of the chosen products. The applicability of the proposed method to an actual product was evaluated using digital cameras. The results show that the eco-efficiency values of products equipped with rechargeable batteries were higher than those products that use alkaline batteries, because of higher quality values and lower environmental impacts. The sensitivity analysis shows that the proposed method was superior to the existing methods, because it enables to identify the quality level of the chosen products by considering all products that have the same functions in the market and because, when adding a new product, the calculated quality values in the proposed method do not have to be changed. 相似文献
46.
作为水质浊度分析标准方法之一的便携式浊度计法,具有快速、简便、准确、可携带至现场的优点,但浊度仪在移动过程中会造成性能的不稳定。为了保证分析结果的精密性和准确性,有必要对浊度仪进行期间核查,因此通过方法比对和标准物质验证两种方法,对浊度仪进行期间核查,并探讨了WGZ-1数字浊度仪所测定的单位“NTU”与单位“度”之间的对应关系。 相似文献
47.
介绍了“数字地球”的概念,并从其技术角度阐述了“数字福建”中的环境保护工作,对核心技术3S技术在环境保护中的应用进行了探讨。 相似文献
48.
49.
R. Newsham P. S. Balson D. G. Tragheim A. M. Denniss 《Journal of Coastal Conservation》2002,8(1):49-54
The rapidly eroding cliffs and foreshore of the Holderness Coast represent one of the largest sources of sediment discharging
in the southern North Sea. For effective coastal management it is important to understand the sediment sources, transport
pathways and depositional sinks. The sediment budget is regarded as one of the key information needs for sustainable planning
and management. In order to quantify the sediment yield from recession of the Holderness Coast, digital photogrammetry has
been used, together with nearshore bathymetric survey data, to produce a single DTM for a length of over 52 km of coastline.
Other data including geological sections, sediment lithology, recession rates and the location of coastal defences have been
added to the DTM to create a GIS for the Holderness Coast. The GIS has been used to predict the volume and nature of the sediment
yield assuming that historical recession rates continue. The GIS can also be used to predict future yields using assumptions
of accelerated recession or the implications of arrested retreat due to construction of defences. 相似文献
50.
基于DEM的山地丘陵区土地利用/覆被研究——以青海湖流域为例 总被引:9,自引:0,他引:9
研究地形对土地利用空间分布格局的影响,对探讨不同地貌部位自然因素和人文因素在土地利用变化过程中的作用具有重要意义。论文以青海湖流域为例,对比各土地利用类型的投影面积与地表真实面积的差异,并从地形(高程、坡度、坡向)角度分析了流域内土地利用的空间分布格局。结果表明:流域投影面积与地表真实面积相差754.79 km2。耕地、居民地、水域、沙地主要分布在3 500 m以下,且坡度小于2°的平地上,耕地和居民地多分布在南坡和西南坡上;林地主要分布在3 500~4 000 m且坡度多在6~25°的缓地和斜坡上,各坡向分布较均匀;草地主要分布在4 500 m以下且坡度小于25°的坡地上;沼泽多分布在3 500~4 500 m且坡度小于25°的河源地区,多分布在北坡和东北坡上;其它用地主要分布在4 000~4 500 m的坡度较大的斜坡或陡坡上。随高度、坡度增加,土地利用程度综合指数呈下降趋势;土地利用综合指数在坡向上呈现:平地>阳坡>阴坡。说明地形在很大程度上影响着青海湖流域的土地利用分布,且这种影响比较符合当地的自然规律和社会经济规律。 相似文献