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1.
计算权重是水质评价中的一个关键环节,不同权重算法将导致评价结果有较大差异。研究基于超标法、熵权法以及主成分分析这3种权重算法,对梧州种质资源保护区水质进行模糊综合评价。结果表明:基于超标法的模糊综合评价对单因子超标比较敏感;基于熵权法和主成分分析法的模糊综合评价全面考虑了各因子对评价结果的影响,二者评价结果一致,且水质类别满足种质资源保护区用水要求,较超标法好。主成分分析法可直接借助SPSS统计分析软件,操作更简单、实用性更强,能更好更高效的服务于保护区水质管理工作。  相似文献   

2.
在分析城市发展结构的基础上,将植物光合作用与呼吸作用理论应用到城市化发展各主体及其协调关系分析上,构建新型城镇化的"城市树"模型,建立评价指标体系。以辽宁省14个省辖市为例,构建灰色关联结构矩阵,采用熵值法对指标进行赋权,用灰色综合评价法进行目标排序。结果表明:辽宁省各城市之间差距明显,大连、沈阳的关联度最高,朝阳的关联度最低;城市内部经济、基础设施、生态平衡、城乡统筹和资源安全发展失衡。实例分析得出"城市树"模型科学合理,为辽宁省新型城镇化发展提供了一条新的思路。  相似文献   

3.
本研究首先介绍了DPSIR模型构建的原理,接着以合肥市为对象,从驱动力、压力、状态、影响、响应5个方面来构建的共36个指标,并采用层次分析法对指标权重的确定和多级灰色关联分析对指标进行综合评价,得出评价结果。合肥市在2004~2005年处于较低可持续发展水平(0.3398、0.3876)、在2010年处于中等可持续发展水平(0.5369)、在2015年处于较高可持续发展水平(0.6016)、在2020年处于较高可持续发展水平(0.7847),该预测评价结果与合肥市城市可持续发展趋势相符。最后采用改进熵值法验证多级灰色关联综合分析结论,计算得出的结果表明,该两种方法评价结论基本相同。因此,本研究对城市总体规划环境影响评价的评价方法的建立与完善,有着较强的实践意义和参考价值。  相似文献   

4.
构建合理的绿色产业评价指标体系是绿色产业评价的关键.根据绿色产业的内涵,依据信息重复指标的剔除标准和加权灰色关联度最大的指标筛选标准,利用R聚类—灰色关联度分析相结合的方法定量筛选指标,构建绿色产业评价指标体系.主要创新与特色,一是通过离差平方和法对评价指标分准则层聚类,保证筛选后不同指标反应的信息不重复;二是通过灰色关联分析求解R聚类同类指标中各指标的加权灰色关联度,遴选关联度最大的一个指标,保证遴选出的指标对绿色产业评价影响最大;三是通过R聚类—灰色关联分析相结合的方法定量筛选指标,构建22个指标涉及绿色生产、绿色消费、绿色环境三个准则层的绿色产业评价指标体系.  相似文献   

5.
传统的模糊综合评价法用于地表水水质评价,当指标数较多时需要设计很多隶属函数,设计和计算工作量皆很大,实际使用不便。在设定指标参照值和规范变换式基础上,将指标按各级标准规范值相近程度进行适当分类,只需分类设计隶属函数即可,大幅减少了计算工作量,使模糊综合评价法应用于地表水水质评价变得简化。  相似文献   

6.
以东营市为例,依据资源型城市的发展规律,运用层次分析法原理构建产业发展综合评价指标体系并得出各指标权重。选取2014年相关数据,结合灰色综合评价法对各产业重要性进行排序,并分析各产业与指标要素之间的关联度。研究结果表明,东营市仍需保持石油开采加工业等的主导地位,同时重点发展化学燃料和制品、电气机械和器材制造等产业,扶持具有较大增长潜力的专用设备制造业。进一步提出打造先进制造业集群,改善产业结构,建设秀美宜居东营,增进民生福祉,创新发展等建议。  相似文献   

7.
陶潺潺  叶亚平  徐慧 《四川环境》2021,40(1):117-126
以水污染灾害为研究对象,从水污染驱动力、污染状态、人类响应3个方面构建水污染灾害综合防治能力评价指标体系,运用物元可拓评价模型,使用熵权法确定权重,计算出环太湖地区的综合关联度并进行分析,结果表明:2014~2018年环太湖地区水污染灾害综合防治能力总体上在不断提升,综合防治能力最好的为无锡,其次为常州、苏州和湖州,嘉...  相似文献   

8.
为了对临湘市的实际生态脆弱性程度做出客观正确的评价,以便对该地区的社会经济持续发展提出科学依据,选取评价指标,构建指标体系并通过层次分析法确定各指标的权重;通过基于三角白化权函数的灰色评价法对各层次指标进行评价和分析并得到综合评价结果。  相似文献   

9.
可以从定性、定量两个角度解决问题的物元可拓法已被广泛应用于各个领域。选取具有代表性的BOD5、NH3-N、石油类、CODcr、粪大肠菌群五项指标为待评物元,取Ⅰ至Ⅴ类水质标准对应的取值范围构造经典域物元矩阵,按照污染贡献率法确定各特征的权重,应用建立的水质评价物元模型计算出关联度0.10,得出该污水处理厂出水环境质量属于Ⅲ级。研究表明,运用物元可拓集模型评价水环境质量具有可信性和实用性。  相似文献   

10.
多目标灰色关联度决策模型分析   总被引:1,自引:0,他引:1  
本文针对多目标决策的复杂性,运用灰色系统分析方法和物元分析理论,建立了决策方案的评价体系并对评价指标进行规范化处理。以决策方案的灰色关联度作为评判准则,建立了一种目标灰色关联度决策模型。  相似文献   

11.
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.  相似文献   

12.
Urban ecological systems: scientific foundations and a decade of progress   总被引:9,自引:0,他引:9  
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.  相似文献   

13.
Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.  相似文献   

14.
In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.  相似文献   

15.
Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.  相似文献   

16.
ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m2) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft3/sec (0.085 to 3.34 m3/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.  相似文献   

17.
Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.  相似文献   

18.
Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.  相似文献   

19.
The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.  相似文献   

20.
The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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