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Search Results: 1 - 10 of 281116 matches for " 李忠奎? "
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治理公路超载超限运输的长效机制和对策研究
, 荣朝和
中国公路学报 , 2005,
Abstract: ?为建立治理超载超限运输的长效机制,首先建立了运输企业收入的计量模型,分析了企业利润与运输价格、运输成本、超载罚款等变量之间的互动关系及企业获得最大利润的条件。在此基础上,针对中国道路货运市场结构的特点,从理性经济人的角度,对运输企业在“惩罚博弈”下可能的行为选择进行了研究;其次结合美国治理超载超限运输的经验,分析了不同执法强度和执法密度组合的执法策略及其适用条件、执法效果等,对中国治理超载超限运输提出了解决方案和具体的政策建议,对中国治理超载超限运输具有指导意义。
公路交通经济增长中的制度因素分析
, 荣朝和
中国公路学报 , 2004,
Abstract: ?在总结传统的经济增长理论(资本决定论、技术进步论、人力资本论、专业化的人力资本和特殊知识积累论)的基础上,采用新制度经济学的分析方法,对建国以来中国公路交通的制度变迁和经济绩效及其相互关系进行了实证分析,指出了制度在公路交通发展中的极端重要性;提出了“生产要素的制度性边界”这一概念,指出制度边界具有随经济、技术等因素变化而不断变化的特性,在此基础上建立了新的经济增长分析框架和模型;为打破制度的“低度均衡”,扩展生产要素的制度边界,最后提出了关于加快制度创新的建议。
桂文化初探
臧德,
南京林业大学学报(自然科学版) , 2004, DOI: 10.3969/j.jssn.1000-2006.2004.07.017
Abstract: <正>通过对桂花的名称、民间传说、诗词歌赋以及桂花与民俗等方面的分析,阐述了桂花文化的内涵。
铜催化异噁唑还原开环清洁高效合成1-氨基-2-乙酰基蒽醌
,仁志,
催化学报 , 2014, DOI: 10.1016/S1872-2067(12)60743-8
Abstract: ?以水为反应介质,水合肼为还原剂,研究了痕量铜催化3-甲基蒽醌-[1,2-c]-异噁唑还原开环反应以清洁高效合成1-氨基-2-乙酰基蒽醌,考察了不同种类过渡金属硝酸盐的催化性能,发现Cu(NO3)2性能最好.加入2.6%的催化剂和1.3倍的水合肼,在室温反应2h,底物转化率和目标产物选择性分别可达到97.2%和95%,TON达到38.产品结构经氢核磁谱和质谱得以确证,主要副产为羟基取代的1-氨基-2-乙酰基蒽醌.此外,提出了铜催化3-甲基蒽醌-[1,2-c]-异噁唑还原开环反应合成1-氨基-2-乙酰基蒽醌的可能反应机理.
基于MATLAB与COMSOL联合仿真的电磁优化设计
Optimum Electromagnetism Design Based on Co-Simulation of MATLAB and COMSOL
 [PDF]

, 许莹, , 昌锟, 胡格丽, 戴银明, 王秋良
Electromagnetic Analysis and Applications (EAA) , 2012, DOI: 10.12677/eaa.2012.11003
Abstract:

遗传算法(Genetic Algorithm简称GA)是借鉴生物遗传学和自然选择机理的一种智能的优化算法。MATLAB中的遗传算法工具箱集成了当前比较成熟的各种遗传操作算子,借助它可以方便地完成各种问题的优化。COMSOL Multiphysics是一款大型的高级数值仿真软件,以高效的计算性能和杰出的多场直接耦合能力实现了任意多物理场的高度精确的数值仿真。为使遗传算法更高效的应用于电磁优化设计,我们研究了在MATLAB中调用COMSOL联合仿真的方法,实现了MATLAB与COMSOL的数据传递。我们将该电磁优化设计方法成功的用于一亥姆霍兹线圈,由此表明了此方法的可行性。
The genetic algorithm (GA) is a type of intelligent optimization algorithm that learns from biological genet- ics and natural selection mechanism. There are varieties of mature genetic operators integrated in the genetic algorithm toolbox of the MATLAB, and we can complete variety of optimization problems easily through the toolbox. COMSOL Multiphysics is a large-scale numerical simulation software. Efficient computing performance and outstanding multi- field direct coupling capabilities ensure highly accurate numerical simulation of arbitrary multi-physics fields. In order to make the genetic algorithm apply to optimum electromagnetism design, we studied the method of calling COMSOL in MATLAB, and completed the data transfer between MATLAB and COMSOL. Then we successfully used this opti- mum design method on a Helmholtz coil, and thus verified the feasibility of this method.

Disturbance rejection and H∞ pinning control of linear complex dynamical networks
,段志生,陈关荣
中国物理 B , 2009,
Abstract: This paper concerns the disturbance rejection problem of a linear complex dynamical network subject to external disturbances. A dynamical network is said to be robust to disturbance, if the H∞ norm of its transfer function matrix from the disturbance to the performance variable is satisfactorily small. It is shown that the disturbance rejection problem of a dynamical network can be solved by analysing the H∞ control problem of a set of independent systems whose dimensions are equal to that of a single node. A counter-intuitive result is that the disturbance rejection level of the whole network with a diffusive coupling will never be better than that of an isolated node. To improve this, local feedback injections are applied to a small fraction of the nodes in the network. Some criteria for possible performance improvement are derived in terms of linear matrix inequalities. It is further demonstrated via a simulation example that one can indeed improve the disturbance rejection level of the network by pinning the nodes with higher degrees than pinning those with lower degrees.
关于中国陆架沙漠化理论几个问题的探讨
,朱大,王颖
地理学报 , 1999, DOI: 10.11821/xb199903010
Abstract: 陆架沙漠化理论主要有两方面的问题第一,该理论所例举的沙漠化证据大多属于不能确认沙漠环境的多解标志;第二,该理论没有阐明冰后期海进过程对陆架上可能存在的风成沙所产生的影响。
轴压层合结构脱层屈曲及其扩展研究进展
周建平,,吴德隆,
力学进展 , 2000, DOI: 10.6052/1000-0992-2000-1-J1998-006
Abstract: 脱层及其进一步扩展可以降低层合结构的强度.首先简单介绍了脱层的一般概念、起因及其分类.从一维脱层、二维脱层和柱壳脱层三个方面介绍了脱层问题的研究概况.指出拉弯耦合和横向剪切效应对脱层结构的屈曲载荷和后屈曲特性影响很大;对于不同的材料特性和尺寸比率,脱层结构的屈曲模态和最终承载能力也不同.最后提出了需进一步深入研究的问题
9cr2凹模淬火裂纹的搭桥修复
高殿,付宇明,白象,文清
材料研究学报 , 2001,
Abstract: ?9cr2凹模淬火裂纹经脉冲放电止裂和电火花熔焊的搭桥修复后,裂纹尖端钝化,模具表面的淬火裂纹被焊合,模具的承载能力和表面光洁度可达到使用要求.
基于形态学属性剖面和单类随机森林分类的道路路域新增建筑物提取方法
A Method for Extraction of Newly-Built Buildings in Road Region Using Morphological Attribute Profiles and One-Class Random Forest

,培军,罗伦,阳柯
- , 2018, DOI: 10.13209/j.0479-8023.2017.073
Abstract: 摘要 提出一种利用形态学属性剖面和单类随机森林分类的道路路域新增建筑物提取方法。用该方法计算路域范围内两时相高分辨率遥感影像的形态学属性剖面, 将得到的形态学属性剖面与光谱特征叠加, 采用改进的单类随机森林分类方法直接提取新增建筑物。以北京市稻香湖地区两时相高分辨率影像作为实验数据, 对比分析该方法与经典两时相直接分类及分类后比较方法的新增建筑物提取精度。结果表明, 综合利用形态学属性剖面和光谱特征提取得到的新增建筑物提取精度比仅使用光谱特征的提取精度显著提高, 其中Kappa系数提高15.11%。此外, 该方法提取结果的Kappa系数比两时相直接分类方法提高1.78%, 比分类后比较方法提高25.15%, 验证了所提方法的有效性。所采用的单类随机森林方法能够有效地处理高维数据, 并可以度量不同特征对分类结果的重要性。
Abstract The authors present a method for extraction of newly-built buildings in road-region using morphological attribute profiles and one-class random forest. The morphological attribute profiles are first obtained from bitemporal high-resolution remote sensing images. The morphological attribute profiles obtained and spectral features are then combined to extract newly-built buildings along road-regions using an improved one-class random forest. Bitemporal images of the Daoxiang Lake area in Beijing are used as experimental data to validate the proposed method, by quantitatively comparing with two conventional change detection methods, i.e., direct bitemporal classification and post-classification comparison methods based on support vector machine. The experimental results show that the accuracy of newly-built building extraction from the proposed method (i.e. using combined spectral features and attribute profiles) is significantly higher than that using only the spectral features, with an increase of 15.11% in Kappa. In addition, the Kappa of the proposed method is 1.78% and 25.15% higher than that of the direct bitemporal classification and that of the post-classification comparison. Therefore, the experimental results validate the effectiveness of the proposed method. Advantages of the one-class random forest include capabilities to effectively deal with high-dimensional data and measure the importance of different features used in one-class classification.
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