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991.
992.
随着城市现代化进程的加快,传统道路照明管理模式已远不能满足现代化的道路照明管理需求,出现了诸如随意建设、高耗能建设和光污染等问题。基于ArcGIS软件设计开发了郑州市道路照明管理规划系统,就该系统的路灯自动配置算法和道路照明评价模型等关键技术进行了研究与实现。路灯自动配置算法可以帮助解决路灯规划建设的难题,道路照明评价模型是照明设施建设是否合理的重要评价手段,这两项技术可有效协助解决道路照明领域存在的无序化、随意性和高耗能的建设做法,对于实现道路照明的科学规范管理和节约能源资源的目的具有一定的参考价值。 相似文献
993.
从力学的角度来考虑空间聚类问题,并结合地理学基本规律提出了一种基于力学思想的空间聚类有效性评价指标(简称SCV)。实验分析表明,本文提出的评价指标能够更准确、高效地对二维地理空间数据的硬聚类结果进行有效性评价。 相似文献
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995.
Christophe Béné Louisa Evans David Mills Solomon Ovie Aminu Raji Ahmadu Tafida Amaga Kodio Famory Sinaba Pierre Morand Jacques Lemoalle Neil Andrew 《Global Environmental Change》2011,21(4):1173-1184
Resilience thinking is an important addition to the range of frameworks and approaches that can be used to understand and manage complex social–ecological systems like small-scale fisheries. However, it is yet to lead to better environmental or development outcomes for fisheries stakeholders in terms of food security, improved livelihoods and ecological sustainability. This paper takes an empirical approach by focusing on the fundamentals of resilience thinking to evaluate its usefulness in developing relevant management interventions in small-scale fisheries in the Niger River Basin in West Africa. The paper presents the outputs of a participatory assessment exercise where both fishery communities and local experts were involved at two different scales. The resilience frame used was designed to facilitate the identification of socially defined thresholds that help delineate the desirability of the current system configuration and provides a diagnosis framework that tailors management solutions to problems in local context. The analysis highlights some key contributions from resilience thinking to the challenge of diagnosis in small-scale fisheries management in developing countries, as well as important contributions that emerge from taking a pragmatic and critical approach to its application. 相似文献
996.
北京快速更新循环预报系统(BJ-RUC)要素预报质量评估 总被引:4,自引:2,他引:2
使用自动站观测资料对BJ-RUC系统预报的北京15个观测站的逐时2 m温度、相对湿度、1小时降水量和风速等地面要素质量进行检验评估。结果表明:BJ-RUC系统预报的2 m温度、相对湿度和风速与实况具有一致的变化趋势,但各要素的预报性能不尽相同。结果表明:(1)对于2 m温度的预报,±1℃误差的准确率为0.2~0.5,±2℃误差的准确率更高;预报性能与预报时效无明显关系;温度预报准确性与季节和日变化有关,春、秋季优于冬、夏季,夜间优于白天。(2)对相对湿度的预报整体偏低,夏季白天偏低、冬季白天偏高。(3)对1小时降水的预报,无论全年还是夏季,晴雨预报准确率很高;对0.1 mm降水的TS评分在0.2左右。(4)对不同站点的预报性能存在明显差异。对平原地区,即海拔高度较低的站点预报性能相对较好,15个站点中,对北京的代表站点(南郊观象台)的预报最为准确;对山区站点的预报性能相对较差,对海拔最高的延庆站的预报性能最差。总体来说,BJ RUC对站点要素预报的变化趋势较好,预报准确率较高,具有很好的参考价值,但要素预报与季节、日变化及海拔高度等因素有关.具体应用时还需做适当订正。 相似文献
997.
Papastergiou P Mouchtouri VA Rachiotis G Pinaka O Katsiaflaka A Hadjichristodoulou C 《Marine pollution bulletin》2011,62(3):590-595
Our aim was to examine the health effects on bathers from exposure to recreational seawater on three beaches with different microbiology quality and bather density through a cohort study. An initial questionnaire and a 10 day follow up were used. Univariate and backward logistic regression analyses were used to asses the risk of developing symptoms or diseases among the bathers. In total, 3805 bathers were included in the study and 149 samples were collected from the three beaches. Despite all the beaches being characterized of high quality the levels of bacterial indicators differed among them. Health effects among bathers were not associated with bacterial indicators. A statistically significant increased risk for symptoms related to respiratory illness, gastroenteritis, medical consultation and use of medication was observed among bathers at the higher bather density beaches. Beach bather numbers should always be taken into account when considering a risk assessment approach. 相似文献
998.
Sánchez-Rodríguez A Sosa-Ferrera Z Santana-del Pino A Santana-Rodríguez JJ 《Marine pollution bulletin》2011,62(5):985-991
The presence of booster biocides in the aquatic environment has been associated with a risk to non-target species due to their proven toxicity. The aim of the present study was to determine the spatial and temporal distribution of common booster biocides in different harbours of the island of Gran Canaria (Spain) and evaluate, by means of a probabilistic risk assessment (PRA), the ecological risk posed by these compounds. With these objectives, a monitoring campaign was conducted between January 2008 and May 2009, collecting a total of 182 seawater samples. Four common booster biocides (TCMTB, diuron, Irgarol 1051 and dichlofluanid) were monitored. Diuron levels ranged between 2.3 and 203 ng/L and Irgarol 1051 between 2.4 and 146.5 ng/L. The ecological risk associated with these levels was always low, however, with probabilities of exceeding the 10th percentile of autotroph toxicity below 3.5%. 相似文献
999.
Benthic faunal data is regularly collected worldwide to assess the ecological quality of marine environments. Recently, there has been renewed interest in developing biological indices able to identify environmental status and potential anthropogenic impacts. In this paper we evaluate the performance of a general polychaete/amphipod ratio along the Norwegian continental shelf as an environmental indicator for offshore oil and gas impacts. Two main trends are apparent: first, a contamination gradient is discernible from where production takes place compared to stations 10,000 m away. Second, the quality of the marine environment has improved over time. These results are consistent with monitoring reports employing a combination of uni- and multi-variate statistics. Thus, we consider this ratio as a relatively simple, useful and potentially cost-effective complement to other more demanding assessment techniques. Because of its strong theoretical basis, it may also be useful for detecting ecological change as a result of other activities. 相似文献
1000.
地震易损性分析方法研究综述 总被引:4,自引:0,他引:4
结构的地震易损性分析对于预测结构的抗震性能、进行结构的抗震设计、加固和维修决策具有重要的应用价值。本文将对近几十年来地震易损性评估方法领域内的重大发展做全面综述,并对易损性分析方法的类别和优缺点及其应用作了总结和讨论。 相似文献