An integrated spatio-temporal GIS toolkit for exploring intra-household interactions

This paper reports on the development of an integrated spatio-temporal GIS toolkit that facilitates the exploration of intra-household interactions. Two tools comprise the toolkit. The first tool, Space-Time Coincidence Analyst, identifies joint activity/travel episodes undertaken by household members. The core of this tool is a set of flexible criteria for classifying episodes as either joint or independent. The second tool, Space-Time Path Visualizer, not only displays space-time paths for household members, but also shows joint episodes undertaken by any two household members together. The toolkit can be applied to any household-based, activity/travel data set so long as required information is specified by the user. To demonstrate its usefulness for research, the toolkit is applied to the TAPS (Toronto Activity Panel Survey) 2002–03 data set. The results suggest that considerable variation exists in the number of joint activity/travel episodes identified using different classification criteria. Specifically, when using restrictive criteria (i.e., same timing, specific activity type/travel mode), only 2,265 joint activity/travel episodes are identified compared to 8,791 when using more flexible criteria. In turn, our results show that certain key attributes for independent and joint activity/travel episodes (i.e., frequency per household, starting time, ending time and duration) also vary under the different classification criteria.

考虑库存成本的配送中心动态选址模型及算法

为了解决传统配送中心选址没有同时考虑库存持有成本和决策环境的动态变化的问题,建立了一种新的模型。首先,利用两步骤近似方法获得(Q,R)库存策略下每一个周期配送中心的库存成本计算公式;然后,针对传统设施动态选址模型对选址成本的不恰当表示进行了修正,并与库存成本计算方法相结合,从而建立考虑库存成本的配送中心动态选址模型。最后,分别用遗传算法、克隆选择算法、粒子群优化算法求解所建立的模型,并从算法的精确度、稳定性、运算速度和收敛性比较了三种算法的性能。算例测试结果表明:所建立的模型是有效的;从总体上看,遗传算法的适应性要强于克隆选择算法和粒子群算法。     

Model Test on Mechanism of Shear Resistance Borne by Concrete Shear Key and Friction of Element Joint of the Immersed Tunnel北大核心CSCD

By scale model tests, it proves the mechanism mode of shear resistance borne by friction of contact area and concrete shear key in different contact stress states and cushion thicknesses of shear key. The results show that friction plays a significant role on shear resistance of element joint. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

主浆小导管与钢架联合支护施工技术的应用

文章以岜其山隧道工程为例,介绍了注浆小导管和钢架联合支护体系在隧道支护施工中的应用技术,主要阐述了其作用机理与施工工艺,并评述了其施工效果。     

Monitoring blade loads for a floating wind turbine in wave basin model tests using Fiber Bragg Grating sensors: A feasibility study

The blade loading contains sufficient information about the unsteady aerodynamics of Floating Wind Turbines (FWTs), and it serves as the basis for advanced controller developments. Wave basin model test is among the most reliable and economical methods for FWT investigations. However, few FWTs were reported being able to monitor the blade loads during wave basin tests. The main obstacles include strict space/mass limitations in model manufacturing and problems associated with signal transmission between rotating blades and stationary signal processing unit. In this paper, the feasibility of detecting blade loads for model FWT in wave basin tests is investigated. An on-line monitoring system is developed based on Fiber Bragg Grating (FBG) sensors and a Fiber Optical Rotary Joint (FORJ). Extensive validation tests are conducted under different environmental and operational conditions. Results show that the proposed FBG-FORJ sensing system presents impressive feasibility and reliability. As the authors know, it is among the first attempts to monitor the blade loads in real-time for model FWTs in wave basin tests. The present study will serve to enrich the knowledge about unsteady aerodynamics of FWTs and lay the foundation for experimental studies on advanced FWT controllers.     

岩体边坡锚注加固模拟试验研究

通过对层状岩石边坡锚注加固模拟剪切试验的研究,对比分析各种结构节理剪切力—剪切位移全程曲线的特点;阐述节理剪切破坏各个阶段的细观过程及不同节理的抗剪切强度和抗剪切刚度的特征。研究表明:锚注加固节理面抗剪切强度并不等于锚杆和胶结面抗剪切强度之和,其强度同步发挥的程度与锚杆钢筋的取材及钢筋配筋率有关;边坡锚注加固后,节理由原来的摩擦型节理和加锚柔性节理变为锚注刚性节理,由于节理的变形减小,可以有效地控制边坡的位移量;锚注节理的抗剪切强度随锚杆与节理面夹角的增大而减小,两者呈反比关系;当剪切力方向与锚杆倾向相同且在锚杆与锚注节理面夹角从90°到30°的变化过程中,锚注节理的抗剪切强度逐渐增大,表现为节理面的C值和φ值逐渐增大。     

天生桥库区水上交通安全管理工作探讨

文章介绍了滇、黔、桂三省（区）海事部门联合开展天生桥库区水上交通安全监督管理工作的历程和成效,总结了跨省共管大型水库水上交通安全整治的经验,并就海事机构下一步如何紧密合作开展库区水上交通安全监管工作进行了探讨。     

Modelling with joint choice of ports and countries of origin and destination: application to Colombian ports

Literature has focused on studying port choice independently or as an element of a supply chain without considering the joint selection with the country of origin/destination of the imports/exports. However, the characteristics and location of a port may make it more attractive to mobilise more freight from/to some particular countries rather than others, making the port choice decision dependent on the country of origin/destination of the cargo. This article proposes advanced econometric models to evaluate simultaneously port choice and the country of origin/destination choice for Colombian imports and exports. Findings suggest that for imports and exports domestic freight rate is the most important variable for the joint choice process. Also, for exports, maritime transit time is more relevant than for imports, while for the frequency of shipping lines the opposite is true. The existence of a trade agreement and the gross domestic product per capita also have a significant influence on the election of a country for exports/imports.     

JU2000E自升式钻井平台桩腿TKY节点 焊接残余应力分析

Ju2000E自升式钻井平台的桩腿TKY节点由于焊接结构复杂,各构件采用高强度大厚板,焊缝多且不规则,焊接残余应力分布复杂,对其评估焊接残余应力非常困难。如今焊接残余应力表面测量配合应力计算是最有效的方法,本文采用一系列的高效计算方法实现了桩腿TKY节点焊接残余应力的高效计算,并通过X衍射法和小孔法验证了计算的可靠性,同时通过计算机模拟软件建立的三维实体模型分析了该结构的应力分布特征。计算结果表明,整个模拟件各方向的峰值拉应力出现在半圆板焊接区域表层,特别是焊趾位置呈现较大的应力集中,而焊缝材料的屈服强度相对半圆板材料屈服强度低,故焊缝区域的各方向拉应力幅值稍低于半圆板焊接区域;整个模拟件各焊缝区域从外到内部的等效应力呈现300-600MPa的较大应力,靠近半圆板的焊趾位置出现较大应力集中,等效应力达到600MPa以上。     

我国地铁与建筑物合建体系研究评述

在总结我国分离式和合并式合建建筑振动转播路径和动力特性的基础上,评述不同类型的既有合建建筑动力响应及振动控制的工程实测和数值分析的研究现状。结果表明:相较于临近地铁建筑,合建建筑在振动强度、激振频段、低频敏感频段、水平振动量级和振动形态等方面具有显著不同;为改善合建建筑的振动环境,可通过降低车体重量、改善轮轨接触面和选择适合的减振轨道与扣件等手段对振源进行振动控制,还可采用整体浮置或局部浮置等隔振方法进行上部结构振动控制。为此,应在适用于合建建筑的通用耦合计算模型、减振轨道实际控制效果、制定匹配合建建筑的振源频率、开发具有针对性的隔振装置产品、浮置隔振中参数优化与关键部位的构造设计等领域进行深化研究。