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1.
刘朝霞 《兰州交通大学学报》2007,26(2):27-29
萧红以她女性的敏感通过儿童视角书写童年经验,而儿童视角文本中往往是儿童身份叙事者和隐含作者即成人身份共存,构成作品的复合视角,儿童简单审美的声音与成人复杂评判的声音轮流切换,形成两套不同的话语系统,在儿童轻松愉快的表层叙述中,隐含了生活本身的沉重与丰富,因而对读者有重要的启发意义. 相似文献
2.
BRAXTON C. DAVIS 《Coastal management》2013,41(4):339-354
Area-based management approaches may be beneficial in integrating sectoral, single-purpose laws and regulations; however, these benefits may not be attained if special area designations are equally sectoral or single-purpose in nature. Over 60 types of special management areas were documented under U.S. coastal programs, and a new classification scheme was developed to allow comparisons and analyses across programs. Results indicate that requirements and incentives for special area designations under the Coastal Zone Management Act did little to standardize or influence area-based management systems associated with state and territory coastal programs. Further, the absence of clear patterns within and between coastal programs with respect to special area policies suggests a limited commitment to this important aspect of coastal management. Continued research is needed to document the effectiveness of the various area-based management approaches presented in this article. 相似文献
3.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(3):421-442
This paper presents the influence of dynamic and geometrical soil parameters on the propagation of ground vibrations induced by external loads. The proposed approach is based on a three-dimensional model, focusing on realistic excitation sources like impulse loads and moving railway vehicles. For the latter, a complete vehicle/track model is developed. The simulation is performed in time domain, offering an interesting approach, compared with classic cyclic analyses. The ground is modelled initially as an elastic homogeneous half-space and additionally as a layered half-space. First, the effect of homogeneous soil properties on ground vibration is analysed. Soil stratification is then taken into account, using various configurations. Analysis reveals that as receiver distance increases ground wave reflection in a layered ground plays an important role in the reduction of ground surface motion. This effect is magnified when the phase velocity wavelength becomes large compared with the depth of the surface layer. 相似文献
4.
动态目标识别中,当摄像机和目标之间相对距离变化时,对于同一目标的多尺度序列图像。虽然目标区域图像大小和清晰度不同,但整体结构分布具有相似性和一致性。根据这一特点,提出基于目标区域网格量化的方法。在目标区域上形成采样网格,通过相对量化提取结构特征矩阵。对于同一目标序列图像中的每一个目标区域,其结构特征矩阵基本不变。结构特征矩阵反映象素分布的自相关性质。进一步,对由干扰引起的灰度值结构分布误差,采用网格区间均值的方法加以解决。目标区域网格量化是对相邻采样点的差值进行量化匹配。区间均值是对少数相邻采样点的进一步匹配。实例表明,本文的方法运算速度快、可靠性高,达到了实用目的。 相似文献
5.
当控制系统的参数发生跳变故障时,系统的性能往往会恶化,甚至会引起系统不稳定。本文讨论了当线性定常系统出现参数跳变故障时的一种容错控制方法。故障检测采用神经网络实现,而容错控制器则采用控制器重构方式设计。仿真结果表明该方法是有效的。 相似文献
6.
《智能交通系统杂志
》2012,16(2):159-173
》2012,16(2):159-173
Highway automation and its evolution involve a multitude of systems issues. Particularly important and difficult in defining a deployment sequence is the very first step, i.e. the first user service involving fully automated freeway driving. However, this importance and the difficulty imply that many factors may severely constrain the initial deployment. After discussing the paramount importance of initial AHS deployment, this paper points out major high-level issues and constraints. Any realistic deployment strategy must take into consideration gradual technology maturation, introduction of new driver role and diminishing conventional driver role for automated driving, high cost of early-generation automation-equipped vehicles, gradual infrastructure modification, gradual commitment of automakers to manufacture and service automation-equipped vehicles, gradual commitment of insurance industry to carry liability, and gradual acceptance by the interest groups and the general public. This paper then proposes a freeway shuttle van service for AHS debut. This user service could be a good candidate for the 1997 AHS demonstration required by ISTEA and has a good chance of leading to a successful long-term AHS deployment supported by the general public. 相似文献
7.
8.
针对目前交通路网中出现的越来越多的非平面路网情况,从构建指路标志系统的需要出发,提出基于复杂结点的面向指路标志系统的非平面路网数据模型,并给出非平面路网拓扑关系的建立方法.将这种数据模型应用于广州市城市路网的指路标志系统中,实现了城市路网中非平面路网上指路标志的自动生成. 相似文献
9.
通过试验手段对现行规程中动态剪切试验的应变控制范围进行分析,研究不同应变值对复合改性沥青胶结料流变性质的影响。试验结果表明,应变值对沥青胶结料复数剪切模量和高温劲度无显著影响,而对相位角则有显著影响,表明其粘性成分会有所增大;其温度因素对复数剪切模量和相位角影响非常显著。 相似文献
10.