Based on previous research work,we present a spectrum deviation method to recognize a foreshock or generalized foreshock in this paper. The criterion to determine whether an event is a foreshock is a wide spectrum for...Based on previous research work,we present a spectrum deviation method to recognize a foreshock or generalized foreshock in this paper. The criterion to determine whether an event is a foreshock is a wide spectrum for an ordinary event,however,a moderate earthquake with foreshock or generalized foreshock has the characteristics of a narrow frequency band,and it deviates to the low frequency. It may be explained by metastable extension in the rupture source or related area of the main shock or regional fragmentation damage and crack nucleation process. The calculation results of two foreshocks,the M_S4. 7 event which occurred before the Yushu M_S7. 1 earthquake on April 14,2010 and the M_S5. 3 event which occurred before the Yutian M_S7. 3 earthquake on February 12,2014,show that the spectra of foreshocks shift,and they are quite different from the nonforeshock seismic spectrum of equivalent size. Therefore,this result can verify the validity of the spectrum deviation method.展开更多
The machining accuracy of workpiece is influenced by its orientation deviation, which is caused by the fixture-workpiece error. Based on the spatial coordinate theory, the orientation deviation of workpiece is measure...The machining accuracy of workpiece is influenced by its orientation deviation, which is caused by the fixture-workpiece error. Based on the spatial coordinate theory, the orientation deviation of workpiece is measured by using an on-machine verification system, which can take into account the errors resulting from fixture manufacturing, installation and adjustment, location and clamping of workpiece. According to the least square method, the model of orientation deviation is built to determine the relationship between the theoretical and actual coordinate systems. The influence of orientation deviation on machining accuracy is quantified, and it is shown that the orientation deviation only affects the dimensional precision and position precision, rather than shape precision. In the experiment, the compensation processing of realtime errors was conducted, and the perpendicularity and inclination errors of the tetragonal part were reduced by 38.46% and 47.06%, respectively.展开更多
提出一种新的基于均匀非周期B样条曲线模型的结构化道路检测算法.算法首先利用Canny边缘检测算法提取道路边缘,然后使用最小二乘法拟合道路标识线,最后利用所提取的道路标识线求取道路中央线,进而完成道路拟合.为了准确定位道路弯道位置...提出一种新的基于均匀非周期B样条曲线模型的结构化道路检测算法.算法首先利用Canny边缘检测算法提取道路边缘,然后使用最小二乘法拟合道路标识线,最后利用所提取的道路标识线求取道路中央线,进而完成道路拟合.为了准确定位道路弯道位置,算法运用最大转向偏差定位(Maximum deviation of position shift,MDPS)方法求解道路模型控制点.实验证明该算法快速、稳定、灵活,可以满足智能导航的要求.展开更多
高水平体育赛事已成为体育事业发展的重要助推手段和城市软实力展示的重要媒介,受到了全世界的重视。面对频繁举办的各类体育赛事,其竞争力评价对城市、主办者、参与者都具有重要意义。为科学评价我国体育赛事的竞争力水平,从基础竞争...高水平体育赛事已成为体育事业发展的重要助推手段和城市软实力展示的重要媒介,受到了全世界的重视。面对频繁举办的各类体育赛事,其竞争力评价对城市、主办者、参与者都具有重要意义。为科学评价我国体育赛事的竞争力水平,从基础竞争力和核心竞争力两个子系统出发构建马拉松赛事竞争力评价指标体系,采用结构熵权法和均方差决策法进行主客观联合赋权,并以我国13个顶级马拉松赛事为例,完成其竞争力综合评价的实证研究。研究发现:(1)经本研究构建评价指标体系实证所得出的我国顶级马拉松赛事竞争力排序与Ga WC(Globalization and World Cities)组织的世界城市排名结果具有较高匹配度,且这一结果较好契合现状认知,表明该评价指标体系和方法可为其他同类体育赛事竞争力的评价研究提供借鉴。(2)实证中马拉松赛事的基础竞争力与举办城市本身的社会经济实力密切相关,香港、北京、上海和广州等国际一流城市举办的马拉松赛事基础竞争力远远高于衡水等欠发达城市。(3)总体上第三方参度与和赛事水平在马拉松赛事核心竞争力中起着关键作用,台北、厦门、兰州等经济总量不大或中等偏上的城市马拉松赛事的核心竞争力排名比较靠前。(4)我国顶级马拉松赛事的综合竞争力排名从高到低为:香港、北京、广州、台北、上海、杭州、兰州、重庆、厦门、太原、深圳、东营和衡水。(5)我国顶级马拉松赛事竞争力可分为五个等级:香港、北京、广州和上海的马拉松赛事为高水平均衡型;台北和兰州的马拉松赛事为高水平单一型;杭州、重庆、太原和深圳的马拉松赛事为中等水平均衡型;厦门和东营的马拉松赛事为中等水平单一型;衡水马拉松赛事为低水平单一型。等级划分基础上还针对政府、组织者和参与者提出了发展运营、赛事组织、参与选择等方面的对策建议。展开更多
基金sponsored by the National Key Technology Support Program of China entitled "Application of Digital Seismic Technology to Mid-and Short-term Prediction of Strong Earthquake"(2012BAK19B02-01)
文摘Based on previous research work,we present a spectrum deviation method to recognize a foreshock or generalized foreshock in this paper. The criterion to determine whether an event is a foreshock is a wide spectrum for an ordinary event,however,a moderate earthquake with foreshock or generalized foreshock has the characteristics of a narrow frequency band,and it deviates to the low frequency. It may be explained by metastable extension in the rupture source or related area of the main shock or regional fragmentation damage and crack nucleation process. The calculation results of two foreshocks,the M_S4. 7 event which occurred before the Yushu M_S7. 1 earthquake on April 14,2010 and the M_S5. 3 event which occurred before the Yutian M_S7. 3 earthquake on February 12,2014,show that the spectra of foreshocks shift,and they are quite different from the nonforeshock seismic spectrum of equivalent size. Therefore,this result can verify the validity of the spectrum deviation method.
基金Supported by National Natural Science Foundation of China (No.50975200)
文摘The machining accuracy of workpiece is influenced by its orientation deviation, which is caused by the fixture-workpiece error. Based on the spatial coordinate theory, the orientation deviation of workpiece is measured by using an on-machine verification system, which can take into account the errors resulting from fixture manufacturing, installation and adjustment, location and clamping of workpiece. According to the least square method, the model of orientation deviation is built to determine the relationship between the theoretical and actual coordinate systems. The influence of orientation deviation on machining accuracy is quantified, and it is shown that the orientation deviation only affects the dimensional precision and position precision, rather than shape precision. In the experiment, the compensation processing of realtime errors was conducted, and the perpendicularity and inclination errors of the tetragonal part were reduced by 38.46% and 47.06%, respectively.
文摘提出一种新的基于均匀非周期B样条曲线模型的结构化道路检测算法.算法首先利用Canny边缘检测算法提取道路边缘,然后使用最小二乘法拟合道路标识线,最后利用所提取的道路标识线求取道路中央线,进而完成道路拟合.为了准确定位道路弯道位置,算法运用最大转向偏差定位(Maximum deviation of position shift,MDPS)方法求解道路模型控制点.实验证明该算法快速、稳定、灵活,可以满足智能导航的要求.
文摘高水平体育赛事已成为体育事业发展的重要助推手段和城市软实力展示的重要媒介,受到了全世界的重视。面对频繁举办的各类体育赛事,其竞争力评价对城市、主办者、参与者都具有重要意义。为科学评价我国体育赛事的竞争力水平,从基础竞争力和核心竞争力两个子系统出发构建马拉松赛事竞争力评价指标体系,采用结构熵权法和均方差决策法进行主客观联合赋权,并以我国13个顶级马拉松赛事为例,完成其竞争力综合评价的实证研究。研究发现:(1)经本研究构建评价指标体系实证所得出的我国顶级马拉松赛事竞争力排序与Ga WC(Globalization and World Cities)组织的世界城市排名结果具有较高匹配度,且这一结果较好契合现状认知,表明该评价指标体系和方法可为其他同类体育赛事竞争力的评价研究提供借鉴。(2)实证中马拉松赛事的基础竞争力与举办城市本身的社会经济实力密切相关,香港、北京、上海和广州等国际一流城市举办的马拉松赛事基础竞争力远远高于衡水等欠发达城市。(3)总体上第三方参度与和赛事水平在马拉松赛事核心竞争力中起着关键作用,台北、厦门、兰州等经济总量不大或中等偏上的城市马拉松赛事的核心竞争力排名比较靠前。(4)我国顶级马拉松赛事的综合竞争力排名从高到低为:香港、北京、广州、台北、上海、杭州、兰州、重庆、厦门、太原、深圳、东营和衡水。(5)我国顶级马拉松赛事竞争力可分为五个等级:香港、北京、广州和上海的马拉松赛事为高水平均衡型;台北和兰州的马拉松赛事为高水平单一型;杭州、重庆、太原和深圳的马拉松赛事为中等水平均衡型;厦门和东营的马拉松赛事为中等水平单一型;衡水马拉松赛事为低水平单一型。等级划分基础上还针对政府、组织者和参与者提出了发展运营、赛事组织、参与选择等方面的对策建议。
