First passage probability of structures under non-Gaussian stochastic behavior

An analytical moment-based method was proposed for calculating first passage probability of structures under non-Ganssian stochastic behaviour. In the method, the third-moment standardization that constants can be obtained from first three-order response moments was used to map a non-Ganssian structural response into a standard Gaussian process; then the mean up-crossing rates, the mean clump size and the initial passage probability of some critical barrier level by the original structural response were estimated. Finally, the formula for calculating first passage probability was established on the assumption that the corrected up-crossing rates are independent. By a nonlinear single-degree-of-freedom system excited by a stationary Gaussian load,it is demonstrated how the procedure can be used for the type of structures considered. Further, comparisons between the results from the present procedure and those from Monte-Carlo simulation are performed.     

紧贴使命任务需求 切实提高新驾驶员培训质量——69220部队积极实践大纲纪实

新大纲颁布以来，69220部队紧贴应急使命任务需求，立足现有训练条件，突出重点，深化训练改革，按照“理论先行、全面试训、精训提高”的思路，积极实践新大纲内容设置、训练条件、组训方法、考评标准。实现了教学科学、组训灵活、秩序正规、效益明显的目标，训练质量稳步提升。深入学习研究。准确把握新大纲的精神实质和内涵该部注重把学习理解新大纲贯穿试训全过程，不断深化思想认识，努力把握新驾驶员训练改革的精髓。     

浅谈钢筋混凝土现浇箱梁温度与收缩裂缝的产生与控制

本文主要对广州市东山口立交及茂生围高架钢筋混凝土现浇箱梁裂缝产生的原因进行分析并提出控制收缩裂缝开展的施工措施。     

长距离线路GPS控制网坐标系选择方法的探讨

本文介绍了长距离线路ＧＰＳ控制网的分级布网方案，并重点对各种不同类型线路ＧＰＳ控制网的参考椭球选择，坐标系的选取提出了不同方案，然后对各种方案进行比较，得出最佳方案。     

Underwater digital terrain model with GPS-aided high-resolution profile-scan sonar images

The whole procedures of underwater digital terrain model (DTM) were presented by building with the global positioning system (GPS) aided high-resolution profile-scan sonar images. The algorithm regards the digital image scanned in a cycle as the raw data. First the label rings are detected with the improved Hough transform (HT) method and followed by curve-fitting for accurate location; then the most probable window for each ping is detected with weighted neighborhood gray-level co-occurrence matrix; and finally the DTM is built by integrating the GPS data with sonar data for 3D visualization. The case of an underwater trench for immersed tube road tunnel is illustrated.     

着眼培训效益 强化综合素质——兰州军区某集团军司训大队大力提高教练员队伍建设水平

<正>近年来,兰州军区所属某集团军司机卫生员训练大队着眼提高新训驾驶员培训效益,积极适应训练改革需求,把教练员队伍建设作为提升训练质量的关键环节来抓,以强化综合素质为突破口,结合专业培训     

槟城二桥主塔索鞍安装定位施工技术

该文结合马来西亚槟城二桥主桥施工实例,对斜拉桥主塔施工过程中索鞍安装定位施工工艺、索鞍劲性骨架预制步骤、现场整体安装及测量定位调整等进行了详细介绍。