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自然资源非市场价值评估的选择实验法:原理及应用分析 总被引:3,自引:2,他引:3
选择实验作为资源环境领域非市场价值评估的重要方法之一.经过近30年的应用与发展,选择实验已经成为目前主要发达国家研究非市场价值评估和公共政策评价最主要的方法之一.但是,该方法在我国的理论研究相对较少,针对性研究与应用缺乏系统性.本文首先介绍了选择实验的原理,对选择实验诞生以来在资源环境和生态管理等领域的应用进行了综述,在举例说明国内外选择实验实践应用的基础上,提出了选择实验在我国可能的应用范围,包括生态补偿、流域管理、珍稀物种保护、自然景观的开发等方面,同时还总结了选择实验在实践应用中应注意的关键问题,旨在为我国相关理论研究与实践提供基础. 相似文献
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笔者通过对目前高校传统课程教学大纲编制及执行中存在问题的探析以及原因分析,提出借鉴美国高校的做法,构建以学习者为中心的课程教学大纲,并对构建以学习者为中心的大纲原因、以学习者为中心的大纲组成进行了较详细的论述。 相似文献
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混凝土结构耐久性的影响因素及对策 总被引:1,自引:0,他引:1
钢筋混凝土结构是应用非常广泛的一种结构形式,但由于其结构自身和使用环境的特点,使得混凝土结构经常存在严重的耐久性问题。通过对国内外钢筋混凝土结构工程耐久性现状的介绍,论述影响混凝土结构耐久性的因素及混凝土的破坏机理,并针对性地提出预防的措施。 相似文献
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在城市地铁区间施工中,预支护方案的选择涉及诸多因素,本文基于地铁工程的特点,综合应用系统工程的模糊数学识别理论与模糊关系优选理论,建立地铁施工预支护方案选择的多目标多层次模糊决策理论模型,以方案的目标特征值作为最低层次的输入,依次以低层次的输出作为高层次的输入,对每一层次进行模糊计算,最后用级别向量的特征值对各个预支护方案进行排序,得出最优方案。通过算例计算得到比较理想的结果,有效地解决受众多模糊性和不确定性因素影响的地铁施工预支护方案的多目标优化决策问题。 相似文献
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Jinju Duan Kui Xie Nathan A. Hawk Shengquan Yu Minjuan Wang 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(1):199-217
This study adds a new perspective to the observations about connectivist interaction behavior in cMOOCs by extending the notion of network building from the perspective of individuals. We explore the possibility of building a learning network named Personal Social Knowledge Network (PSKN) to support in the monitoring of learning performance and interaction in cMOOCs. The sample in this study included 284 preservice teachers and their learning lasted approximately 12 weeks. Data were primarily gathered by PSKN graphs. The results revealed a correlation between connectivist interaction measured by the PSKN (including density structure) and learning performance. The results also revealed differences in connectivist interaction behavior and patterns, indicated by PSKN (densities and structures), for high- and low-performing learners in cMOOCs. The high-performing learners show deeper knowledge interaction and social communication in addition to simple knowledge sharing and social communication. Additionally, as time passed and the PSKN of high-performing learners extended further, their interaction behavior became more complex and their role had gradually changed from “learning” to “teaching” as well as from knowledge acceptance to knowledge creation in cMOOCs. 相似文献
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Minjuan Wang Ruimin Shen 《British journal of educational technology : journal of the Council for Educational Technology》2012,43(4):561-575
The demands of an increasingly knowledge‐based society and the dramatic advances in mobile phone technology are combining to spur the growth of mobile learning (mLearning). However, for mLearning to attain its full potential, it is essential to develop pedagogy and instructional design tailored to the needs of this new learning environment. At present, there is a lack of research on message design for mLearning. Towards these ends, this paper explores the principles and processes of message design for mLearning, including the influence of learning and cognitive theories, human–computer interaction principles, devices and methodologies. And it presents a number of practical guidelines for designing instructional messages for mLearning. 相似文献
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以新沂河大桥施工为例,分析预应力组合箱梁调平层在施工过程中产生裂缝的原因,提出在施工过程中应重视的几个工艺环节,在此基础上,还提出调平层裂缝的解决方法与质量控制措施. 相似文献
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基于选择试验模型的生态系统服务支付意愿差异及全价值评估——以渭河流域为例 总被引:2,自引:0,他引:2
对流域生态系统服务进行全价值评估有利于相关流域治理政策的建立,实现流域的可持续发展。本文应用选择试验模型法,对我国流域生态系统服务的非市场价值进行评估,并以渭河流域陕西段为例进行实证研究。在生态功能属性和指标的合理选取基础上进行选择试验模型设计和问卷调查,进一步分析渭河流域城乡居民对流域生态系统服务的认知差异,以及测算相关样本的支付意愿,最终进行非市场价值估算。研究结果表明:1相对于城镇居民,农村居民不在意水土流失方面生态系统服务的改善,而更关心水资源数量和质量,以及自然景观和生态旅游条件等方面的改善;2渭河流域居民对水资源质量这一生态指标具有最高的支付意愿,对水土流失强度这一生态指标具有次高的支付意愿,而对自然景观这一生态指标具有最低的支付意愿;3陕西省渭河流域平均每户居民每年愿意为渭河流域生态系统服务的改善支付624.22元,且城镇居民的支付意愿(830.34元/户)明显高于农村居民(525.46元/户)。陕西省渭河流域生态系统服务每年的非市场价值为8.68亿元。 相似文献