半潜式支持平台靠泊海洋生产平台碰撞概率建模

为有效解决深水半潜式支持平台靠泊海洋生产平台过程中存在的碰撞问题,从碰撞事故发生原因入手,借鉴挪威船级社(Det Norske Veritas,DNV)DNV-RP-107规范中的船与海洋平台碰撞概率模型和美国公路与运输协会(American Association of State Highway and Transportation Officials,AASHTO)《美国公路桥梁防船撞设计指南》中的船桥碰撞概率模型,将支持平台发生向前的过分偏移引起的碰撞场景分为漂移碰撞和动力碰撞2种,建立事件树,得到支持平台靠泊海洋生产平台碰撞概率模型。在此基础上,估算支持平台靠泊碰撞海洋生产平台的概率,由此评估碰撞风险,为半潜式支持平台靠泊碰撞海洋生产平台场景下的相关规范制定提供参考。     

故障树分析（FTA）技术在机车安全性评估中的应用

阐述FTA分析程序以及定性和定量的分析方法及目的;以某蓄电池电力机车为例,选择触电危险作为顶事件,说明触电故障树的构建过程。通过定性与定量分析,得出导致触电安全事故发生的最小割集和概率,由此评估机车的运用安全性;指出了FTA技术在机车安全性评估中的重要作用及其分析过程中需注意的问题。     

Large-scale dynamic transportation network simulation: A space-time-event parallel computing approach

This paper describes a computationally efficient parallel-computing framework for mesoscopic transportation simulation on large-scale networks. By introducing an overall data structure for mesoscopic dynamic transportation simulation, we discuss a set of implementation issues for enabling flexible parallel computing on a multi-core shared memory architecture. First, we embed an event-based simulation logic to implement a simplified kinematic wave model and reduce simulation overhead. Second, we present a space-time-event computing framework to decompose simulation steps to reduce communication overhead in parallel execution and an OpenMP-based space-time-processor implementation method that is used to automate task partition tasks. According to the spatial and temporal attributes, various types of simulation events are mapped to independent logical processes that can concurrently execute their procedures while maintaining good load balance. We propose a synchronous space-parallel simulation strategy to dynamically assign the logical processes to different threads. The proposed method is then applied to simulate large-scale, real-world networks to examine the computational efficiency under different numbers of CPU threads. Numerical experiments demonstrate that the implemented parallel computing algorithm can significantly improve the computational efficiency and it can reach up to a speedup of 10 on a workstation with 32 computing threads.     

Integrating capacity analysis with high-speed railway timetabling: A minimum cycle time calculation model with flexible overtaking constraints and intelligent enumeration

Compared with most optimization methods for capacity evaluation, integrating capacity analysis with timetabling can reveal the types of train line plans and operating rules that have a positive influence on improving capacity utilization as well as yielding more accurate analyses. For most capacity analyses and cyclic timetabling methods, the cycle time is a constant (e.g., one or two hours). In this paper, we propose a minimum cycle time calculation (MCTC) model based on the periodic event scheduling problem (PESP) for a given train line plan, which is promising for macroscopic train timetabling and capacity analysis. In accordance with train operating rules, a non-collision constraint and a series of flexible overtaking constraints (FOCs) are constructed based on variations of the original binary variables in the PESP. Because of the complexity of the PESP, an iterative approximation (IA) method for integration with the CPLEX solver is proposed. Finally, two hypothetical cases are considered to analyze railway capacity, and several influencing factors are studied, including train regularity, train speed, line plan specifications (train stops), overtaking and train heterogeneity. The MCTC model and IA method are used to test a real-world case involving the timetable of the Beijing–Shanghai high-speed railway in China.     

基于GOOSE机制的城市轨道交通中压环网继电保护方案优化

针对目前城市轨道交通中压环网继电保护存在的问题,提出了基于GOOSE(面向通用对象的变电站事件)机制的中压环网的继电保护优化方案,有效地解决了传统过流保护级差配合困难的问题.该方案是以GOOSE光纤以太网为基础,以闭锁逻辑为核心的数字通信电流保护方案.将GOOSE信号进行分类,并对中压供电环网系统各种可能出现的故障进行动作行为分析.最后,通过RTDS(动态数字仿真系统)仿真试验,证明该方案在各种故障情况下,都能保证继电保护的选择性、速动性、灵敏性和可靠性.     

某航道桥下部结构受船舶撞击后安全性能评估及修复

为评估航道桥下部结构的船撞安全性,以遭受船撞的某内河航道桥为研究对象,采用有限元方法和相关规范计算受撞击的5号桥墩自身水平抗力、船撞力、墩顶位移,并从墩顶位移和桥墩抗力两方面对受撞桥墩的安全性进行评估。结果表明:5号桥墩的横桥向和顺桥向抗力均由桩基强度控制,分别为2528 kN和1142 kN;事故船撞击工况下,墩顶最大横桥向和顺桥向位移分别为7.6 mm、13.4 mm,满足位移限值要求;沿横桥向和顺桥向的船撞安全系数分别为1.67和0.94,顺桥向的自身抗力不足以抵抗瞬时船撞力,导致桥墩桩基础受损,建议采用增大截面法对受损桩基础进行加固补强,并设置独立防撞墩以保障桥梁结构安全。基于分析过程,总结了桥梁下部结构船撞安全评估的一般流程。     

基于绿色飞行的航空器离场累积事件噪声控制研究

航空业的迅猛发展,在带来巨大经济、社会效益的同时,也造成日益严重的噪声污染.为缓解机场周边噪声问题,贯彻"绿色飞行"理念,本文从飞行程序优化和飞行架次调整两方面进行航空器离场噪声控制研究.采用计权等效连续感觉噪声级为评价指标,应用累积事件噪声计算模型,以广州白云机场为例,绘制噪声等值线图,计算噪声影响面积,分析噪声控制效果及原因.结果表明,CCO减噪程序和飞行架次调整两种方法均可有效减少噪声影响面积,但噪声控制方法各有利弊,实践过程中应扬长避短灵活运用.     

高职院校群体性事件成因及应对机制研究

高职学生群体性事件是学生释放压力与发泄不满的非理性方式,这种不理性行为会造成学校混乱,负面影响很大。因此,掌握高职院校学生特点,分析群体性事件的内外部原因,并在此基础上提出有效的应对机制,能够维护校园的和谐与稳定。     

浅谈市政公用工程设计变更的监理

强调了市政公用工程设计变更监理工作的重要性,阐述了施工前、施工中加强事前控制和事中控制的方法,建议加强监理人员职业道德教育,建立完善监理工作各项管理制度,以提高监理效果,确保监理目标的实现。     

FUZZY RELIABILITY ANALYSIS OF STRUCTURE

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