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261.
Andreas C. Bryhn Antonio Jiménez Alfonso Mateos Sixto Ríos-Insua 《Journal of environmental management》2009
A multi-attribute analysis by means of the general multi-attribute analysis (GMAA) decision support system was performed in order to rank different strategies for good water quality with respect to trophic state, and good conditions for waterfowl, in the lagoon Ringkøbing Fjord, Denmark. The remedial strategies included nutrient abatement and the construction of facilities to increase the water exchange between the lagoon and the sea. The analysis showed that it is essential to keep the mean annual salinity level constant, since a drastic change in salinity may cause massive destruction of the macrophyte belt with large effects on the water quality and waterfowl abundance. It may be cost-effective to build and maintain a saltwater pumping station or a second sluice to increase the seawater inflow. Further nutrient abatement may not be cost-effective, at least not on time-scales shorter than 20 years, but the utility from nutrient abatement increases if a second sluice is built additionally. However, all of the remedial strategies, except decreasing the salinity, were projected to cause rather small changes in the effect variables compared to the no action alternative. 相似文献
262.
In this article we present a framework for assessing climate change impacts on water and watershed systems to support management
decision-making. The framework addresses three issues complicating assessments of climate change impacts—linkages across spatial
scales, linkages across temporal scales, and linkages across scientific and management disciplines. A major theme underlying
the framework is that, due to current limitations in modeling capabilities, assessing and responding to climate change should
be approached from the perspective of risk assessment and management rather than as a prediction problem. The framework is
based generally on ecological risk assessment and similar approaches. A second theme underlying the framework is the need
for close collaboration among climate scientists, scientists interested in assessing impacts, and resource managers and decision
makers. A case study illustrating an application of the framework is also presented that provides a specific, practical example
of how the framework was used to assess the impacts of climate change on water quality in a mid-Atlantic, U.S., watershed. 相似文献
263.
In the United States, the common interest often is conceived as a by-product of the pluralist, interest-group-driven democratic
process. Special interests dominate in many political arenas. Consequently, we have lost the language, vocabulary, and ability
to talk about the common interest. The way to reverse this trend is to develop and practice with new tools that allow us to
articulate what we mean by the common interest in specific contexts. In this article, we leveraged the literature on procedural,
substantive, and pragmatic decision making to illustrate how they work together to demonstrate whether and how the common
interest was served in three case studies of Healthy Forests Restoration Act implementation on the Apache-Sitgreaves National
Forest in Arizona. In two of the cases we found that the common interest was mostly served, while in the third case it was
not. Our results raise questions about the ability of procedural criteria or substantive criteria alone to determine effectiveness
in decision making. When evaluated together they provide a more complete understanding of how the common interest is or is
not served.
相似文献
Toddi A. SteelmanEmail: |
264.
煤与瓦斯突出预测的支持向量机(SVM)模型 总被引:6,自引:4,他引:2
基于支持向量机(SVM)分类算法,考虑影响煤与瓦斯突出的主要因素,建立了煤与瓦斯突出预测的SVM模型。该模型选取开采深度、瓦斯压力、瓦斯放散初速度、煤的坚固性系数以及地质破坏程度5个指标作为模型输入量,同时将煤与瓦斯突出程度划分为无突出、小型突出、中型突出和大型突出4个等级,进而使其评判结果更为细化。以实测数据作为学习样本进行训练,建立相应判别函数对待判样本进行预测。通过算例分析,表明该模型的方法对煤与瓦斯突出预测的合理性与有效性,可以在实际工程中推广。 相似文献
265.
城市火灾案例库辅助决策方法的研究 总被引:6,自引:1,他引:5
在对城市火灾事故案例进行全面调查、统计和分类分析的基础上,提出一种城市火灾案例特征属性的表示框架,对特征属性进行了层次化和结构化,同时对属性值的取值进行较为科学而严格的定义,进而应用混合相似度度量方法和粗糙-模糊集方法提炼案例中蕴涵的灭火救援知识,给出一种灭火救援辅助决策过程模型;通过查找最相似案例和案例库提炼出相关的灭火救援规则进行灭火救援辅助决策;成功进行了实例验证。该模型的建立可为城市火灾案例智能决策系统的研究提供参考。 相似文献
266.
针对边坡稳定性影响因素复杂,传统的稳定性分析存在计算量大、计算过程复杂的问题,提出了边坡稳定性的支持向量机预测方法。分析了边坡稳定性的影响因素,选择影响边坡稳定性的边坡重度、内聚力、摩擦角、边坡角、边坡高度、孔隙压力比6项指标为特征向量。并运行该方法对典型边坡实例进行了预测,预测结果与边坡稳定性实际状态及其它方法预测结果相吻合,表明了支持向量机在边坡稳定性预测中的可靠性和有效性。 相似文献
267.
硫化矿石自燃倾向性鉴定技术研究 总被引:5,自引:2,他引:3
根据硫化矿石自燃过程的复杂性,通过程序升温氧化(TPO)实验对硫化矿石吸附性能进行研究,提出了硫化矿石程序升温氧化(TPO)吸氧鉴定的方法,测试矿样温度从30℃到1000%条件下的总吸氧量和自热起始温度作为硫化矿石自燃倾向性鉴定指标,并对其进行分类;提出了基于支持向量机的硫化矿石自燃倾向性预测方法,通过预测建模最终达到了预期数据与实际数据的最佳拟合。 相似文献
268.
Polychlorinated biphenyls (PCBs) in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor 1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors (BCFs) of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgKow relationship. The relationship between lgBCFs and lgKow followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgKow, suggesting that a metabolism of the higher Kow PCB congeners occurred. These results support the author's conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners. 相似文献
269.
Tsegaye Tadesse Menghestab Haile Gabriel Senay Brian D. Wardlow Cody L. Knutson 《Natural resources forum》2008,32(4):265-279
Reducing the impact of drought and famine remains a challenge in sub‐Saharan Africa despite ongoing drought relief assistance in recent decades. This is because drought and famine are primarily addressed through a crisis management approach when a disaster occurs, rather than stressing preparedness and risk management. Moreover, drought planning and food security efforts have been hampered by a lack of integrated drought monitoring tools, inadequate early warning systems (EWS), and insufficient information flow within and between levels of government in many sub‐Saharan countries. The integration of existing drought monitoring tools for sub‐Saharan Africa is essential for improving food security systems to reduce the impacts of drought and famine on society in this region. A proactive approach emphasizing integration requires the collective use of multiple tools, which can be used to detect trends in food availability and provide early indicators at local, national, and regional scales on the likely occurrence of food crises. In addition, improving the ability to monitor and disseminate critical drought‐related information using available modern technologies (e.g., satellites, computers, and modern communication techniques) may help trigger timely and appropriate preventive responses and, ultimately, contribute to food security and sustainable development in sub‐Saharan Africa. 相似文献
270.
Conjunctive use of saline/non-saline irrigation waters is generally aimed at minimizing yield losses and enhancing flexibility
of cropping, without much alteration in farming operations. Recommendation of location-specific suitable conjunctive water
use plans requires assessment of their long-term impacts on soil salinization/sodification and crop yield reductions. This
is conventionally achieved through long-term field experiments. However such impact evaluations are site specific, expensive
and time consuming. Appropriate decision support systems (DSS) can be time-efficient and cost-effective means for such long-term
impact evaluations. This study demonstrates the application of one such (indigenously developed) DSS for recommending best
conjunctive water use plans for a, rice-wheat growing, salt affected farmer’s field in Gurgaon district of Haryana (India).
Before application, the DSS was extensively validated on several farmers and controlled experimental fields in Gurgaon and
Karnal districts of Haryana (India). Validation of DSS showed its potential to give realistic estimates of root zone soil
salinity (with R = 0.76–0.94; AMRE = 0.03–0.06; RMSPD = 0.51–0.90); sodicity (with R = 0.99; AMRE = 0.02; RMSPD = 0.84) and relative crop yield reductions (AMRE = 0.24), under existing (local) resource management
practices. Long term (10 years) root zone salt build ups and associated rice/wheat crop yield reductions, in a salt affected
farmer’s field, under varied conjunctive water use scenarios were evaluated with the validated DSS. It was observed that long-term
applications of canal (CW) and tube well (TW) waters in a cycle and in 1:1 mixed mode, during Kharif season, predicted higher average root zone salt reductions (2–9%) and lower rice crop yield reductions (4–5%) than the existing
practice of 3-CW, 3-TW, 3-CW. Besides this, long-term application of 75% CW mixed with 25% TW, during Rabi season, predicted about 17% lower average root-zone salt reductions than the cyclic applications of (1-CW, 1-TW, 2-CW) and
(2-CW, 1-TW, 1-CW, i.e., existing irrigation strategy). However, average wheat crop yield reductions (16–17%) simulated under
all these strategies were almost at par. In general, cyclic-conjunctive water use strategies emerged as better options than
the blending modes. These results were in complete confirmation with actual long-term conjunctive water use experiments on
similar soils. It was thus observed that such pre-validated tools could be efficient means for designing, local resource and
target crop yield-specific, appropriate conjunctive water use plans for irrigated agricultural lands. 相似文献