镇江市轨道交通3号线方案可行性探讨

为了适应城市的快速发展,镇江超前做好了轨道交通的规划建设工作,但是由于城市东西通道沿线用地开发定位不详及城市的快速扩张等因素,镇江轨道3号线位方案出现了一些问题。针对这些问题,从镇江城市未来的城市发展格局、客流走廊、用地开发、城市近期需求角度出发,从根本上分析轨道3号线的建设条件,并提出了新的轨道交通3号线方案。     

Review on Theoretical Delay Estimation Model for Signalized Intersections

Traffic delay is an effective index for estimating the performance of a signalized intersection. In this study, we provide a comprehensive review of the theoretical delay estimation model over the last ca. 90 years. For fixed-time signalized intersections, we classified the estimation development process into three stages. Stage 1 covered 1920s–1970s, when approaches based on steady-state theory were derived. These methods obtain accurate predictions with low degrees of saturation, but overestimate the delay with higher saturation and cannot provide reasonable results for oversaturated conditions. To accommodate high saturation, time-dependent models were proposed and improved in Stage 2, 1970s–2000s, using coordination transformation techniques. Progression factors to account for the filtering impact from upstream intersections were also introduced during this period. Due to inaccurate approximation of certain specific traffic conditions, some modified approaches and supplementary terms were derived from 2000 onwards (Stage 3), which facilitate the evolution of the delay estimation method and improved approximation results. Some new techniques, including artificial intelligence algorithms, were also introduced into delay estimation in this era. We also describe theoretical delay measurement methods for actuated control intersections with a similar time line. From our summary of the evolution of theoretical delay models, we highlight some deficiencies and future research directions.     

Real-time optimization of ship energy efficiency based on the prediction technology of working condition

Ship energy efficiency management and control is an effective strategy to improve the marine economy and reduce CO₂ emission. The determination of the best navigation speed under different working conditions is the basis and premise for real-time improvement of ship energy efficiency. In this paper, the working condition in short distance ahead of the ship related to navigation environment factors was predicted by the method of wavelet neural network, and then the best engine speed for the optimal energy efficiency under different working conditions could be determined through the established ship energy efficiency real-time optimization model. Further, by presetting the ship engine at this optimal speed, the ship energy efficiency could be guaranteed at the optimal state when the ship arrived at the navigation environment ahead of the ship, thus achieving real-time optimization of ship energy efficiency under different navigation environment factors. Experimental studies showed that the proposed optimization model was effective in energy saving and emission reduction, which could provide theoretical guidance for optimal sailing of the ship in service. Compared to traditional setting speed navigation methods, our proposed method has more practical significance to the improvement of ship energy efficiency.     

Multicomponent decomposition of a time-varying acoustic Doppler signal generated by a passing railway vehicle using Complex Shifted Morlet Wavelets

Complex Shifted Morlet Wavelets (CSMW) present a number of advantages, since the concept of shifting the Morlet wavelet in the frequency domain allow the simultaneous optimal selection of both the wavelet center frequency and the wavelet bandwidth. According to the proposed method, a cluster of CSMW wavelets is used, covering appropriate ranges in the frequency domain. Then, instead of directly processing the instantaneous frequency of each CSMW, an invariance approach is used to indirectly recover the individual harmonic components of the signal. This invariance approach is based actually on the same rotational approach, using the same matrix properties, which consists the core of the well known ESPRIT algorithm. Moreover, the DESFRI (DEtection of Source Frequencies via Rotational Invariance) approach is introduced to support the proposed CSMW method to semi-automated selection of the center frequency of the applied Morlet window. This approach is based on the singular values that are extracted as an intermediate product of the proposed decomposition process. By the application of the method in a multi-component synthetic signal a way to select the critical parameters of the Morlet wavelet, is investigated. The method is further tested on a time-varying acoustic Doppler signal generated by a passing railway vehicle, indicating promising results for the estimation of the variable instantaneous frequency and the multi-component decomposition of it.     

基于ADAMS优化设计的某潜艇用流水孔启闭装置

为最大限度提高潜艇战斗力,增强潜艇快速性,减小航行噪声,流水孔启闭装置被广泛应用于新型潜艇中。以某型潜艇流水孔启闭装置为研究对象,建立运动仿真模型,利用ADAMS仿真软件提供的优化设计功能,对运动机构进行优化设计,优化后,启动装置工作时对驱动力的要求明显降低。同时,针对该装置在实艇装配时可能出现的安装误差,通过添加约束条件进行再次优化设计。再次优化的结果显示,驱动力的波动维持在较低水平,从而进一步提高了设备的可靠性和环境适应性。     

安全道路条件计算研究综述与展望

为了促进中国道路安全工程的发展,系统梳理了国内外安全道路条件计算领域的学术研究现状、热点前沿、存在问题、具体对策及发展前景.总结了安全道路条件计算发展现状并对其未来发展趋势进行了展望,分别对道路线形、路面条件和驾驶人工作能力方面的研究内容进行了细化和梳理.为改善道路交通安全的严峻形势、完善道路交通安全评价理论与方法,采用驾驶工作负荷理论及表达方法的研究成果,研究驾驶期望行为(运行速度)、驾驶人自身能力阈限(生心理安全舒适感)、道路条件(包括路线平面、纵断面、横断面)、路面平整度等互动关系.研究驾驶人安全舒适性道路条件计算的多因素表达,为安全的道路条件设计与运行管理提供理论与方法支撑.     

基于非负矩阵分解的高速列车走行部工况识别

根据高速列车振动信号数据的特点,针对高速列车走行部工况的识别,提出了一种基于非负矩阵分解(NMF)算法的工况识别模型。该模型通过数据处理获得具有辨识度的工况数据集,使用K-means、谱聚类、近邻传播和模糊C均值4种聚类算法获得初步识别结果。聚类算法的初步识别结果作为NMF算法的输入,获得最终识别结果。相比NMF算法与聚类算法的识别结果,NMF算法具有更高的准确率,本文验证了NMF算法在高速列车工况识别方面的有效性和高效性,为高速列车的工况识别提出了一种有效的解决方案。     

急弯河段新建船闸上游引航道通航条件研究

在急弯河段已建枢纽上新建船闸工程,船闸布置受限因素众多,通航条件复杂。为分析船闸引航道通航水流条件,建立袁河石洲枢纽180正态物理模型,开展急弯河段船闸上游引航道通航水流条件试验,对比隔流堤不同长度口门区的流速分布,同时结合自航船模试验分析船闸口门区通航条件。结果表明,延长隔流堤对减小口门区横向流速峰值、改善流态作用明显;隔流堤延长250 m时,石洲船闸上游引航道最高通航流量可达到规范要求的20 a一遇洪水。     

铁路隧道排水方法与工程实践

为解决隧道洞身施工及运营过程中可能遇到的排水问题,以叙永至毕节铁路、西安至成都高铁、改建成都至昆明铁路隧道工程为工程依托,采用理论分析与工程实践相结合的方法,对隧道洞身排水设计方法进行总结分析。研究结果表明,隧道洞身排水应根据不同环境条件进行设计,基于不同环境条件,提出5种排水系统设计方法,分别为盲管+沟槽排水方法、侧沟连接排水方法、集水廊道排水方法、过水涵洞排水方法及泄水洞排水方法。盲管+沟槽排水方法适用于一般地段,侧沟连接与集水廊道排水方法适用于地下水单侧集中出水地段,过水涵洞排水方法适用于隧底施工揭示岩溶过水通道地段,泄水洞排水方案适用于隧道沟槽排水能力不能满足需求的地下水强烈发育地段。5种排水方法各有优缺点,隧道排水设计应根据环境条件、投资大小、排水效果等综合比较,选择其中最合适的排水方案。     

多年冻土地区温度对水稳砂砾

水泥稳定砂砾在多年冻土地区路面基层应用中普遍出现了板体性差、温度低等问题,通过模拟多年冻土地区实际温度变化和单一恒温的强度试验,与标准养生条件对比分析了特殊温度条件对水泥稳定砂砾混合料强度形成的影响。研究得出,多年冻土地区特殊的低温和负温条件将明显延缓混合料强度的形成速度;养生温度对混合料强度形成的影响存在临界状态,当第二天养生温度达到研究得出的临界温度分界点7℃后．只通过提高养生温度来进一步提高强度或加快强度增长的效果并不明显。结果表明．多年冻土地区特殊的温度条件是基层出现板体性差和强度低等问题的主要原因．解决问题的关键在于采取提高混合料设计强度、掺入外加剂、保温和封闭施工等技术措旋,保证和提高早期强度,降低负温和低温影响程度。