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291.
Transportation - Coupling activity-based models with dynamic traffic assignment appears to form a promising approach to investigating travel demand. However, such an integrated framework is... 相似文献
292.
针对反舰导弹的运动特性,进行了三维的仿真分析,并研究了反舰导弹的超音速和强机动给目标预测带来不可避免的误差的情况。重点介绍了拦阻射击的概率密度函数公式,通过仿真分析得出结论,在目标预测误差存在而且并不是很小时,拦阻射击比跟踪集火射击在命中率方面有很大的提升。在此基础上,对阵列式高射频武器的结构设计做了初步探讨。 相似文献
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从近年来北京市公安交通管理信息化应用现状出发,对北京市道路交通管理信息化建设工作进行了全面、深入的调查研究,总结归纳了近年来全市道路交通管理在挖潜科技系统效能、构建信息化应用体系、提升路面交通管理水平所取得的成绩,并对未来信息化建设的发展完善进行了展望。 相似文献
298.
Has the transport-led economic growth effect reached a peak in China? A panel threshold regression approach 总被引:1,自引:0,他引:1
Using China’s province-level panel data from 1987 to 2010, this study explores the optimal level of transport infrastructure accumulation maximizing the growth rate. We investigate under what circumstances can additional transportation infrastructure capacity positively affect economic growth, based on panel threshold regression models. Our empirical findings suggest that there is a non-monotonic relationship between the stock of transport infrastructure and the long-run growth rate. The magnitude of transport-led economic growth effect significantly depends on the level of the existing transport network. The empirical results identify two endogenous cut-off points of efficiency of transport-led economic growth effect. When the highway network density is lower than 0.17 km/km2, an insignificant positive relationship between highway infrastructure accumulation and economic growth was found. When the highway density is estimated between 0.17 and 0.38 km/km2 or higher than 0.38 km/km2, expanding the highway network has a significant positive effect on economic growth, but the magnitude of the impact is weaker in the latter, with the estimated coefficients equal to 0.23 and 0.09 respectively. Although China still enjoys a positive economic growth effect led by building more large-scale highway infrastructure, the magnitude of the effects of most provinces in China has already passed the saturation point and continuously expanding the highway network is not very productive. 相似文献
299.
海洋救助拖船是对海上遇险人员和船舶实施有效救助的专用船舶.为对接我国海洋战略发展需求,要适应在深远海大风浪恶劣海况条件下对海上遇险人员和船舶的有效救助.针对海洋救助拖船适应深远海救助需求的基本功能设置,就船舶救助和人命救生的拖曳救助作业、对外消防灭火、海面人命救生、海面搜救、获救人员救治及保障等主要设备及设施配置作技术探讨. 相似文献
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ABSTRACTThis paper addresses the reconsideration of price bubbles specific to the shipping freight market based on the method of the Generalized Supremum Augmented Dickey–Fuller (GSADF). This approach offers the opportunity to recognize multiple bubbles and set their corresponding original and final dates. Empirical results reveal that four bubbles existed in the shipping freight market between October 1988 and February 2018 in which freight deviated from fundamental values. Strong demand (especially in China), the supply capacity, crude oil prices and U.S. dollar fluctuations are potential explanations for the first three bubbles. The global financial crisis that burst in 2008 is the major factor results in the last bubble. Hence, we must distinguish the potential reasons of bubbles in different periods and take measures such as promoting economic multipolarization, strengthening the bargaining power of China, building an effective information transfer system, employing financial derivatives and accelerating the consolidation of the shipping industry to alleviate the negative influences on global seaborne trade. 相似文献