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211.
Nora M. Znotinas Keith William Hipel 《Journal of the American Water Resources Association》1979,15(1):44-59
ABSTRACT: Procedures are presented for comparing and evaluating alternative engineering designs for a particular water resources project. By using certain aspects of fuzzy set theory, it is possible to introduce both quantitative and qualitative considerations into the decisionmaking process. In addition, the viewpoints of the various interest groups involved with the water resources development can be realistically incorporated by the evaluation techniques for the alternative designs. Methods are given for eliminating undesirable alternatives and thereby obtaining a reduced set of possible feasible solutions to the problem. Because of the flexibility of the evaluation methods, the viable alternatives should not only satisfy economical, technical. environmental and other types of constraints, but these possible solutions should be politically feasible as well. A method is formulated for checking the sensitivity of the feasible results with respect to the factors that are considered in the analysis. 相似文献
212.
Roger D. Hansen Michael F. Torpy Michael Kemp David Mills 《Journal of the American Water Resources Association》1980,16(5):862-865
ABSTRACT: The authors conducted a mail survey of 600 employers in the government and private sectors who were thought to hire water track environmental engineers. Of a total of 148 respondents, over 80 percent employed a combined total of over 2,800 environmental engineers. The survey addressed two basic questions: (1) what is the quality of graduate education recently trained engineers have received, and (2) what effect does a nonengineering undergraduate degree have on an engineering graduate student's employment potential. In answer to the first question, respondents indicated that engineering graduates were deficient in report writing, business law (contracts and specifications), economics and finance, and practical design. Many employers stated that students could better prepare themselves for employment by (1) obtaining professional experience through internships and summer or part-time jobs, and (2) learning to communicate effectively, both orally and in writing. In answer to the second question, 50 percent of the respondents indicated that engineers without an engineering undergraduate degree would not necessarily be limited in their abilities to perform engineering duties. 相似文献
213.
ABSTRACT: An extensive research program in hydrometeorology was recently initiated in the Chicago region. Major objectives are to 1) develop a real-time, prediction-monitoring system for storm rainfall using a combination of weather radar and telemetered raingage data, 2) determine precipitation measurement requirements for hydrologic design, operation, and modeling purposes, 3) define the time-space characteristics of heavy rainstorms in the Chicago urban area, and 4) establish methods for applying the Chicago findings in other cities. Basic components of the field measurement program are a network of over 300 recording raingages in 4000 mi2 in and around Chicago, plus two sophisticated weather radar systems for obtaining real-time information on storm parameters pertinent to optimizing operation of urban water resources systems. The raingage networks are to be used to compile information relevant to both design and operational aspects of urban hydrology. Radars are to be used primarily in developing the real-time operational techniques. Testing and evaluation of the real-time operational system will be done in cooperation with the Metropolitan Sanitary District of Chicago, operator of one of the most complex urban water control systems among major metropolitan areas. 相似文献
214.
Roy W. Koch Thomas G. Sanders H. J. Morel-Seytoux 《Journal of the American Water Resources Association》1982,18(5):815-821
ABSTRACT: The detection of change in a hydrologic varaible, particularly water quality, is a current problem. A method is presented for testing whether there has been a shift in the mean of a hydrologic variable based on the well established bivariate normal distribution theory. In this technique, the dependent, or target, and the independent, or control, variables are formed as weighted linear combinations of the mean values at a number of locations in a selected target and control area. The weighting factors are determined based on a mathematical programming technique which minimizes the conditional coefficient of variation thereby minimizing the number of observations required to detect a change of a preselected magnitude in the mean of the target area. The result is a situation where a savings in the number of observations required to detect a change is a consequence of adding more stations: the space-time tradeoff. Two applications of the technique are presented, the first using electrical conductivity (EC) data from two sets of river basins and the second using EC data from a set of basins as the target variable and annual discharge as the control. The results indicate that a significant savings in time can be achieved by using this method. 相似文献
215.
Thomas E. Croley 《Journal of the American Water Resources Association》1974,10(6):1123-1132
ABSTRACT: Water resource development has progressed to the stage where various human factors are now being considered in reservoir design and operation. The introduction of human factor objectives complicates the problem since they are noncommensurate with other objectives and they are difficult to identify quantitatively. Some of the problems that now arise concern the proper methods for consideration of several different, sometimes subjectively identified, objectives in reservoir planning. The classical systems analysis approach to decision making for multiple objective problems is outlined and the inherent difficulties associated with multiple objectives and subjective estimates are identified. Techniques being used in reservoir design and operation are reviewed and discussed. An alternate technique for considering noncommensurate, subjectively identified, objectives, which relates the objectives in terms of real trade-off costs and eliminates the need for a priori estimates of objective worth is then presented. The method is illustrated with three examples, including a reservoir operation problem and a cooling tower design problem. 相似文献
216.
易燃液体燃烧痕迹识别对助燃剂放火火灾调查至关重要。选用丙纶地毯和PVC地板革作为纤维和塑料地板的代表,以工业酒精作为易挥发助燃剂的代表,研究酒精用量、灭火方式等对燃烧痕迹形成及痕迹稳定性的影响。通过与未加载酒精的痕迹对比,发现丙纶地毯因热稳定性较差,燃烧后往往能形成烧坑或烧洞,其燃烧轮廓以典型的灰化形式存在,加载酒精的部位熔融严重,与地面紧紧粘连在一起;PVC地板革因为表面光滑,酒精在其表面不断流淌,燃烧后会留下清晰的轮廓,类似于细线状的印痕,而地板革本身基本不会燃烧。燃烧熄灭的方式也会对其炭化程度、燃烧图痕、残余形状产生影响。 相似文献
217.
218.
Wendy A. Williams Mark E. Jensen J. Chris Winne Roland L. Redmond 《Environmental monitoring and assessment》2000,64(1):105-114
Accurate delineation and characterization of valley-bottom settings is crucial to the assessment of the biological and geomorphological components of riverine systems; yet, to date, most valley-bottom mapping endeavors have been done manually. To improve this situation, we developed automated techniques in a Geographic Information System (GIS) for delineating and characterizing valley-bottom settings in river basins ranging in size from approximately 1,000–10,000 km2. All procedures were developed with ARC/INFO GIS software and fully automated in Arc Macro Language (AML). The GRID module is required for valley-bottom delineation and slope calculations; whereas characterization (i.e., measuring the width of the valley-bottom zone) requires Coordinate Geometry (COGO) in the ARCEDIT module. The process requires three inputs: a polygon coverage of the analysis area; an arc coverage of its hydrography, and a grid representing its digital elevation. The AML is designed to operate within a wide range of computer memory/disk space options, and it allows users to customize several procedures to match the scale and complexity of a given analysis area with available computer hardware. 相似文献
219.
滨海城市是我国经济最发达的地区,近年来经济与城市建设均得到迅速发展,城市土地开发力度加大,由此起起的环境工程地质问题也日趋严重。本文分析了我国滨海城市环境工程地质问题的主要类型,研究了环境工程地质问题的成灾特点。 相似文献
220.
Recent and rapid landscape changes have occurred over large areas in Mediterranean Basin. Wildfires and human activities are the most important disturbances at landscape-level due to their ecological and socio-economic impacts. The increasing demand which society places on the forest landscapes has led us to develop a tool to identify the economic landscape value around natural protected areas. Our research focused on the integration of social, ecological and economic components of landscape management based on stated social preferences and contingent valuation method (CVM). Landscape value research has been motivated by the need to assist land use planning and environmental management.Geographic Information Systems (GIS) have provided new opportunities to spatially distributed modeling of landscape quality. Correlations were found between the representativeness of the landscape and its sense of belonging, and the contingent rating. Landscape with intensive agricultural practices and mining areas were the least preferred landscapes. There was a notable variation in the economic landscape value attributed to the study area based on the considered CVM scenario, ranging from 1,253,075.1 Euros to 3,650,827.8 Euros. We added the geospatial allocation of willingness to pay according to five landscape quality categories. Our approach could be used to identify priority areas for conservation based on maximizing landscape value, and would be useful in detecting interesting or conflict areas associated with new management and planning alternatives. In this sense, this approach offers managers to seek territorial management strategies to increase economic efficiency in the allocation of resources. 相似文献