Extreme value prediction of nonlinear ship loads by FORM using Prolate Spheroidal Wave Functions

In this study, a method for predicting the extreme value distribution of the Vertical Bending Moment (VBM) in a flexible ship under a given short-term sea state is presented. The First Order Reliability Method (FORM) is introduced to evaluate the Probability of Exceedances (PoEs) of extreme VBM levels. The Karhunen-Loeve (KL) representation of stochastic ocean wave is adopted in lieu of the normal wave representation using the trigonometric components, by introducing the Prolate Spheroidal Wave Functions (PSWFs) to formulate the wave elevations. By this means, reduction of the number of stochastic variables to reproduce ocean wave is expected, which in turn the number of computations required during FORM based prediction phases is significantly reduced. In this study, the Reduced Order Model (ROM), which was developed in our previous studies, is used to yield the time-domain VBMs along with the hydroelastic (whipping) component in a ship. Two different short-term sea states, moderate and severe ones, are assumed. The FORM based predictions using PSWF for normal wave-induced VBM are then validated by comparing with those using the normal trigonometric wave representation and Monte Carlo Simulations (MCSs). Through a series of numerical demonstrations, the computational efficiency of the FORM based prediction using PSWF is presented. Then, the validation is extended to the severe sea state where the whipping vibration contributes to the extreme VBM level to a large degree, and finally the conclusions are given.     

“双一流”建设背景下一流工科课堂建设探讨

“双一流”建设正在如火如荼的开展中,在“双一流”建设的重要机遇下,打造“一流课堂”是提高高等人才整体素质和专业能力的重要途径。通过目前存在的突出问题剖析,提出通过教学内容、教学方法和教学手段三个方面为抓手,进行不断改进和完善传统课堂教学模式,加速推进“一流课堂”建设普遍化,整体提高课堂教学质量,提升学校整体教学水平。     

Spatial and Temporal Changes in Access Rights to Shellfish Resources in British Columbia

Over the past decade, the shellfish and finfish aquaculture industry has expanded rapidly in coastal British Columbia (BC) Canada. Foreshore and nearshore shellfish and finfish aquaculture leaseholds are sited in close proximity or in direct competition with habitat for wild shellfish. As a result, some wild shellfish harvesters believe shellfish farms are significantly reducing access to beaches and estuarine areas for wild harvesting, or that salmon farms are contaminating wild shellfish stocks. In this article, Geographic Information Systems (GIS) are used to analyze spatial and temporal trends in the growth of shellfish and finfish aquaculture tenures in BC, while interviews with stakeholders in coastal communities are used to explore user conflicts and the implications of changing access rights on the distribution of marine resources. Qualitative and quantitative findings suggest that shellfish aquaculture provides significant economic opportunities for coastal communities, but that such development may hold increased risk of spatial conflicts over marine habitat as the aquaculture industry continues to grow.     

Quasi-dynamic traffic assignment with residual point queues incorporating a first order node model

Static traffic assignment models are still widely applied for strategic transport planning purposes in spite of the fact that such models produce implausible traffic flows that exceed link capacities and predict incorrect congestion locations. There have been numerous attempts to constrain link flows to capacity. Capacity constrained models with residual queues are often referred to as quasi-dynamic traffic assignment models. After reviewing the literature, we come to the conclusion that an important piece of the puzzle has been missing so far, namely the inclusion of a first order node model. In this paper we propose a novel path-based static traffic assignment model for finding a stochastic user equilibrium in general transportation networks. This model includes a first order (steady-state) node model that yields more realistic turn capacities, which are then used to determine consistent capacity constrained traffic flows, residual point (vertical) queues (upstream bottleneck links), and path travel times consistent with queuing theory. The route choice part of the model is specified as a variational inequality problem, while the network loading part is formulated as a fixed point problem. Both problems are solved using existing techniques to find a solution. We illustrate the model using hypothetical examples, and also demonstrate feasibility on large-scale networks.     

海洋平台结构系统疲劳可靠性分析的一阶二次矩方法

本文提出了海洋平台结构系统疲劳可靠性分析的一阶二次矩方法，海洋平台结构系统中疲劳破坏的失效途径用一由若于失效单元组成的并闻系统来模拟，失效单元代表了平台结构中易发生疲劳破坏的管节点，文中寻出了失效单元依次破坏时的疲劳寿命与它们在其他单元均未破坏下的疲劳寿命之间的一船关系式，并用一阶二次矩方法计算上述并联系统的失效概率。     

"先简支后连续"梁桥的设计及应用

“先简支后连续”体系梁在公路及市政桥梁建设中得到广泛应用。阐述这种结构体系的合理性，重点分析其计算、设计及施工要点。简要介绍其应用现状。     

盐田港集装箱码头二期工程地基处理的施工监理

通过叙述现场试验确定地基处理施工方案的过程,说明施工监理处理设计变更及进行质量控制的方法。     

首件鉴定的实践与体会

首件鉴定是产品质量控制过程的关键环节,从运用首件鉴定程序的实际情况出发,着重阐述产品首件鉴定的范围、时机、鉴定内容,以及在运行首件鉴定过程中遇到的瓶颈及其解决对策,提出针对具体情况进行层次化首件鉴定的理念。     

物业开发地铁车辆段首层盖板高度影响因素分析

地铁车辆段进行物业开发是今后车辆段建设的发展趋势,但目前物业开发车辆段首层盖板高度设计不尽相同,盖板高度设计的合理性、经济性需进一步分析研究。提出并分析物业开发车辆段首层盖板高度的主要影响因素,结合主要影响因素对广州市轨道交通21号线镇龙车辆段首层盖板高度的设计及其对工程投资的影响进行具体分析说明。研究得出,镇龙车辆段首层盖板高度各主要影响因素的合理取值,进而得出其首层盖板合理的设计高度并有效降低工程造价。     

龙高公路路况调查及路面处治

以龙高一级公路大修工程为例,阐述了一级公路大修的过程,以及在路况调查、路面处治中需考虑的问题.