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951.
952.
Resource managers require objective methodologies to optimize decisions related to forest road deactivation and other aspects of road management, especially in steep terrain, where road-related slope failures inflict extensive environmental damage. Decision analysis represents a systematic framework that clearly identifies real options and critical decision points. This framework links current decisions with expected future outcomes and provides advantages such as a common currency to systematically explore the liability consequences of limited budget expenditures to road deactivation and other road-related activities. Furthermore, the decision framework prevents the analysis from becoming hopelessly entangled by the vast number of possibilities generated by the alternative occurrences, magnitudes, and consequences of landslide/debris flow events and provides the information required for the first step of an adaptive management process. Here, a structured analysis of potential environmental risks for a road deactivation project in coastal British Columbia, Canada is presented. The application of decision analysis generates a ranking of the expected benefits of proposed deactivation activities on various road sections. The ranking distinguishes between road sections that offer high expected benefit from those that offer moderate to low expected benefit. Seventeen of 171, 100–m road segments accounted for 18% of the cumulative cost and 98% of the cumulative expected net benefits from road deactivation. Furthermore, the cost of deactivating a section of road is related to the expected benefit from such deactivation, thus providing the basis for more effective resource allocation and budgeting decisions. 相似文献
953.
Istanbul has experienced rapid increases in population to more than 12 million people, which has created infrastructure problems of water supply and wastewater treatment and disposal. In this article, the achievements and approaches of the Istanbul Water and Sewerage Administration (ISKI) to solve the water shortage problem and to improve services are summarized. Istanbul had a very severe water shortage problem in 1994 because of ignorance of the implementation of the needed projects. After reviewing the reasons and causes of the problem, new priority criteria adopted after 1994 are given. Following the implementation of the projects determined according to the aforementioned criteria, water supplied has exceeded the water demand. The added capacity is equal to one to three times of the capacity built up to 1994 for water treatment, service reservoirs, pumping stations, transmission lines, and the water distribution network; water quality has been improved the meet local and international potable water standards. Unaccounted for water has been reduced from 60% to 27%. The percentage of treated wastewater has been increased from 10% to 90% in 8 years, resulting in drastic improvements and rehabilitation of the Golden Horn and coastal water quality. Through improved customer services, complaints were reduced from 33% in 1994 to 0.3%. Some of the main criteria and the approaches behind this success are summarized.
Published online 相似文献
954.
Rough Set Rule Induction for Suitability Assessment 总被引:4,自引:0,他引:4
Berger PA 《Environmental management》2004,34(4):546-558
The data that characterize an environmental system are a fundamental part of an environmental decision-support system. However, obtaining complete and consistent data sets for regional studies can be difficult. Data sets are often available only for small study areas within the region, whereas the data themselves contain uncertainty because of system complexity, differences in methodology, or data collection errors. This paper presents rough-set rule induction as one way to deal with data uncertainty while creating predictive if–then rules that generalize data values to the entire region. The approach is illustrated by determining the crop suitability of 14 crops for the agricultural soils of the Willamette River Basin, Oregon, USA. To implement this method, environmental and crop yield data were spatially related to individual soil units, forming the examples needed for the rule induction process. Next, four learning algorithms were defined by using different subsets of environmental attributes. ROSETTA, a software system for rough set analysis, was then used to generate rules using each algorithm. Cross-validation analysis showed that all crops had at least one algorithm with an accuracy rate greater than 68%. After selecting a preferred algorithm, the induced classifier was used to predict the crop suitability of each crop for the unclassified soils. The results suggest that rough set rule induction is a useful method for data generalization and suitability analysis. 相似文献
955.
Ji ZG 《Environmental management》2004,34(2):159-169
Offshore drilling for oil and gas has been conducted since the early 1900s. Oil and gas under the seabed continue to be an important part of the energy resources of the United States. The need to balance the value of these resources against the potential for environmental damage is an important concern. This article explains why and how the Minerals Management Service (MMS) of the US Department of the Interior uses research in physical sciences to help fulfill its environmental goals, and it provides background information on the role of physical sciences in decision-making for Outer Continental Shelf (OCS) oil, gas, and other minerals development. Established in the 1970s, the MMS Environmental Studies Program is a highly focused marine research program designed to provide the environmental information necessary for OCS energy and nonenergy minerals planning and development activities. The physical sciences research supported by MMS includes physical oceanography, oil-spill risk analyses, atmospheric sciences, and sand and gravel studies. Instead of giving a comprehensive review on physical sciences research in MMS, this article presents sample MMS studies and illustrates how these studies are utilized to support decision-making in environmental management.Published online
Note: This version was published online in June 2005 with the cover date of August 2004. 相似文献
956.
J. E. Wiebe 《Journal of the American Water Resources Association》1972,8(6):1189-1197
Large-scale water projects have long been undertaken for the benefit of people. Information appears to be needed as to who benefits as a result of these projects. The hypothesis was tested that regional income and employment benefits would be closely related to areas where water projects were located. The analytical procedure centered on cluster analysis used to delineate counties in the Tennessee River Watershed on the basis of changes in selected variables over different periods. The hypothesis was rejected. It was concluded that benefits of water projects were not necessarily confined to isolated areas near projects but were regional. 相似文献
957.
铁路安全预警系统的研究和实现 总被引:4,自引:2,他引:2
结合哈尔滨铁路局实际运营系统 ,基于事故树分析理论 ,探讨了铁路安全预警系统的实现。首先论述了事故树的建立方法和以事故树分析法为基础的铁路安全预警系统的核心算法 ,然后讨论了具体实现的数据结构和事故树编码方法 ,最后简要提出了铁路安全预警系统的系统设计思想 相似文献
958.
Samura Alusine Al-Agha Omar Tuncel Semra G. 《Water, Air, & Soil Pollution: Focus》2003,3(5-6):111-129
The concentrations of heavy, trace elements and major ions measuredin the Uluda and Bursa aerosols were investigated to assess size distributions, spatial and temporal variability, sources and source regions affecting the composition of aerosols in Uluda and Bursa. A total of 81 samples were collected in two sites, one in Bursa city and another in the Uluda Mountain during two sampling campaigns. Daily samples were collected using a high volume sampler on Whatman 41 cellulose filters in Uluda, while three days interval samples were collected in Bursa using an automatic dichotomous sampler on PTFE Teflon filters. Samples were analysed for 15 trace and heavy metals (Al, Fe, Ba, Na, Mg, K, Mn, Ca, Cu), (V, Pb, Cd, Cr, Ni, Zn), and 4 major ions (SO4
2-, NO3
-, Cl-), (NH4
+) using ICP-AES, GFAAS, HPLC and UV/VIS Spectrophotometer,respectively. In general, concentrations of the metals measured inUluda aerosols were lower than those in Bursa. The concentrations of crustal elements were higher in summer than winter, while anthropogenic elements had higher concentrations in winter than summer. Most of the mass of crustal elements was concentrated in the coarse mode while the mass of the heavy metals was concentrated in the fine mode. Factor analysis revealed four factors with sources including crustal, industrial and combustion. Back trajectory calculations were used to determine long range contributions. These calculations showed that contributions were mostly from European countries, former Soviet Union countries, Black Sea and North Africa. 相似文献
959.
Cao Junji Lee Shungcheng Zheng Xiangdong Ho Kinfai Zhang Xiaoye Guo Hai Chow Judith C. Wang Hongbin 《Water, Air, & Soil Pollution: Focus》2003,3(2):213-229
In April 1998, two intense dust storms were generated in CentralAsia and transported eastward across East Asia (15 and 19 April). This article presents the chemical characterization ofHong Kong (HK) aerosols during the dust storms. During the 15 Aprildust storm, hourly respiratory suspended particles (RSP)(particle diameter smaller than 10 m) concentrationsmonitored at 7 sites in Hong Kong reached the peak valuessynchronously between 9 and 11 a.m. on 17 April, in which thehighest concentration was 267 g m-3. Analysis ofthe RSP samples showed that concentrations of crustalelements (Ba, Ca, Cd, Cr, Fe, Mg, K+) and anthropogenicspecies (As, Ni, Pb, Zn, NH4
+, NO3
-,SO4
2- and total carbon) were substantiallyenhanced. Enhancement of these species was more than afactor of 2 to 14 relative to the non dust period. The totalcarbon content was high, at 59 g m-3 (notincluding carbonate), and the enrichment factors of Asand Pb on 17 April were 122 and 117, respectively. Thisimplied that anthropogenic materials together with mineraldust were transported to HK from Mainland China. Based onmaterial balance calculations, mineral dust contributed41% to the observed RSP mass on 17 April, which was 2 times thatof the nondust sample (22%). From the 5-day backwardtrajectory analysis, this storm was transported directlyfrom Northwest China to HK. However, there was nocorresponding observation for the 19 April dust stormaerosol. Consequently, 15 April storm had stronger impact onHK's atmosphere than 19 April storm. Compared to the HK AirQuality Objective, 15 April dust storm did not cause seriousair pollution in HK. 相似文献
960.
This study developed a noise prediction model for elevated mass rapid transit (MRT) platforms. Relevant physical and operational parameters (e.g. cruise speed, acceleration and deceleration rates for trains, building fa?ade setbacks and so on) were collected from the Bangkok mass transit system (BTS), the first elevated MRT system operated in Bangkok, Thailand. The equivalent continuous sound pressure levels (L(Aeq)) were collected from both sides of the MRT stations at the center of each platform. The relevant parameters were collected on both platforms and ground level, on both sides of MRT stations. These parameters were statistically tested to determine their correlation with MRT noise. The final model was built from highly correlated parameters using multiple regression analysis with a stepwise regression technique. Statistical evaluation showed a high degree of goodness-of-fit test for the model to the observed data. Therefore, it can be efficiently used for the projection of MRT noise in the affected areas. 相似文献