隧道检测裂缝的图像处理研究

裂缝是隧道衬砌最常见的病害之一,基于近几年快速发展的工程检测系统与图像处理算法的研究,提出基于CCD相机的衬砌裂缝检测系统来采集裂缝图像。通过比较均值滤波、中值滤波、维纳滤波、自适应中值滤波和加权邻域滤波比较,选择自适应中值滤波进行图像增强。结合直方图阈值分割法、Otsu最大类间方差阈值和局部阈值分割法,对增强后图像进行二值化处理比较,Otsu法较好地保留了裂缝的边缘信息,证明了该算法的有效性,为后续裂缝信息的提取奠定了基础。     

浅谈苏州河郊区段常见问题及对策建议

苏州河是上海市建设"卓越的全球城市"的代表性空间和标志性载体,具有丰富的人文资源和滨水景观.《苏州河沿岸地区建设规划》(2018-2035)将外环外郊区段定位为生态廊道,实现生态保育和休闲游憩功能.结合近年来苏州河(青浦区)堤防专项维修工程中的经验,分析苏州河郊区段存在的主要问题,并提出对策和建议.     

粤西地区水稳施工质量通病成因及防治措施

针对粤西地区夏季高温多雨、蒸发量大及降雨以短时间小范围暴雨为主的气候特点,对水稳施工质量通病成因进行分析。从原材料控制、混合料级配控制、水泥剂量及含水量控制、混合料离析控制、混合料施工雨水防控、层间清理及水泥浆洒布质量控制、水稳养生控制和开放交通控制等多方面阐述了水稳质量通病防治措施要点。     

喷水推进装置在船舶上的应用发展

介绍了船舶喷水推进的装置组成；分析了喷水推进所具有的优点和缺点；探讨了喷水推进的关键技术，适用喷水推进的船舶以及喷水推进的发展趋势。     

Inverse identification of wheel–rail contact forces based on observation of wheel disc strains: an evaluation of three numerical algorithms

In this paper, three numerical algorithms for the identification of wheel–rail contact forces based on measured wheel disc strains on an instrumented railway wheelset are discussed and compared. The three algorithms include one approach resting on static calibration, one that is applying a Kalman filter and the third is exploiting an inverse identification scheme. To demonstrate and evaluate the alternative methods, two load cases including periodic excitation by sinusoidal wheel–rail irregularities and transient excitation by an insulated rail joint are considered. Based on a previously presented vehicle–track interaction model in the time domain, load scenarios are defined by taking the calculated vertical wheel–rail contact forces as the reference force to be re-identified by the proposed algorithms. The reference contact forces are applied on a finite element model of the wheel to generate synthetic observation data, that is, radial strains at the positions of the strain gauges, serving as input to the identification procedures. It is concluded that the inverse identification scheme leads to superior accuracy at higher computational cost. If on-line implementation and evaluation is required, the Kalman filter generates better accuracy than the static calibration approach.     

The design of single allocation incomplete hub networks

The hub location problem deals with finding the location of hub facilities and allocating the demand nodes to these hub facilities so as to effectively route the demand between any origin–destination pair. In the extensive literature on this challenging network design problem, it has widely been assumed that the subgraph induced by the hub nodes is complete. Relaxation of this basic assumption constitutes the starting point of the present work. In this study, we provide a uniform modeling treatment to all the single allocation variants of the existing hub location problems, under the incomplete hub network design. No network structure other than connectivity is imposed on the induced hub network. Within this context, the single allocation incomplete p-hub median, the incomplete hub location with fixed costs, the incomplete hub covering, and the incomplete p-hub center network design problems are defined, and efficient mathematical formulations for these problems with O(n³) variables are introduced. Computational analyses with these formulations are presented on the various instances of the CAB data set and on the Turkish network.     

斜拉索风雨振研究现状和尚待解决的问题

斜拉索风雨振严重威胁斜拉桥的安全，是研究热点之一。综合叙述了风雨振的危害，介绍了包括现场观测、风洞试验、理论分析、数值流体计算等研究方法，说明了风雨振发生的可能机理，介绍了现有的控制振动的措施，以及尚待解决的问题，为该问题的进一步解决提供参考。     

当前中等职业学校招生工作中存在的问题与对策

中等职业教育作为我国教育事业的重要组成部分,在国家现代化建设中发挥着越来越重要的作用。但随着经济社会的不断向前发展,中职教育中也发生了一些新情况、新问题。其中,中职招生难问题就其中比较突出的一个,它将直接影响中职学校的生存和发展,不得不引起我们的思考。我们应审时度势、高瞻远瞩,采取有效措施,及时化解中职招生中的问题,为中职学校的健康、可持续发展打下坚实的基础。     

新公约下的海上医疗救护培训探讨

为了提高培训质量,对新公约下海上医疗救护培训现状及存在的问题进行分析.从统一教材、题库、实训项目及考评标准中内容、要求及运用情况进行实证对比.结果显示教材过于专业化和理论化;题库缺乏综合性、全面性和实用性;实训内容简单;评估形式复杂.指出教材应简单通俗而不失弹性;题库应强化案例及技能练习;实训内容应够用实用;考评应兼顾学员综合表现.     

“工程力学”课程教学中加强高职学生工程能力和兴趣培养的探索

概述了工程力学性质,对学生现状进行了分析,提出了从引入工程案例、制作力学模型、苦练教师内功等三个方面来加强高职学生工程能力和兴趣的培养。