江海通航顶推船铰接装置的波浪载荷模型试验研究

在不规则波中对某5000吨级的江海通航顶推船进行了两销式铰接装置的载荷模型试验.模型试验数据的无因次分析表明,在浪向角60°情况下铰接装置受力比其它浪向角时都要大,并且铰接装置受到的水平弯曲力比垂向弯曲力、轴向力大得多.推导了服从Weibull概率分布变量的短期概率极值预报公式.针对试验数据,进行了实船12小时短期概率极值预报,结果表明,在设计波高4.2m时,超越概率1%时的最大弯曲力相当于该顶推船推轮的排水量.本次试验及其数据预报的极值可供设计同类型铰接装置的江海通航顶推船时参考使用.     

基于模糊决策的炮兵火力打击目标价值研究

运用模糊决策理论,对炮兵火力打击目标价值进行了分析与排序,并结合实例说明了该方法的具体应用,旨在为指挥员和指挥机关的科学决策提供依据。     

吉布提LNG厂址波浪极值推算

在吉布提LNG厂址的设计过程中,由于当地可用水文资料缺乏,现场观测活动起步晚、持续时间短(仅1 a),无法满足多年重现期设计波浪要素推算的需求,给后续工作带来了较大的困难。以CCMP风场数据作为驱动,基于波作用量平衡方程建立印度洋大范围波浪数学模型、嵌套的亚丁湾中等范围模型及工程区小范围模型,在现场实测资料的基础上,结合同期的Jason卫星轨道资料对模型进行验证对比,模型验证结果良好。在此基础上,计算了1988—2017年的逐时波浪要素过程,并据此构建出年极值波浪序列,利用P-III型分布函数推算工程区深水处的各重现期波浪极值,结合不同水文条件计算得出工程区的设计波浪要素。     

Using the sustainable modified TAM and TPB to analyze the effects of perceived green value on loyalty to a public bike system

This article explores the effects of perceived green value, perceived green usefulness, perceived pleasure to use, subjective norms and perceived behavioral control on green loyalty to a public bike system. The mediators between perceived green value and green loyalty and a moderator of general attitude toward protecting the natural environment are also discussed. The aim of this research was to understand how to establish green loyalty via the other dimensions based on the sustainable modified technology acceptance model (modified TAM), the theory of planned behavior (TPB), and a moderator. The findings reveal that perceived pleasure to use and subjective norms have the strongest power to influence loyalty for both users and non-users. The implications of this finding are that fun in people’s lives has a strong influence on sustainable continuous use of public bikes, and that subjective norms are more effective for non-users. In addition, environmental attitude has stronger moderating effects for non-users than for users on perceived green usefulness, perceived pleasure and subjective norms. Therefore, governmental policies should promote the attitude of protecting the natural environment, perceptions of pleasure, and subjective norms so as to increase green loyalty to public bike-sharing.     

美国气垫登陆艇围裙技术发展及分析

文中介绍了美国气垫登陆艇(LCAC)围裙的技术发展历程,随着艇装载量、耐波性、全寿命周期维护等总体性能和作战使用要求的提高,围裙技术在不断发展改进。通过利用先进的计算分析及三维设计软件,提高了围裙设计放样精度与寿命,降低了波浪中阻力,改善高速抗埋首及侧滑安全性,减轻自重也减少了维护工作量。此外,围裙改进均经过拖曳船模试验以及实艇的长期运行考验。这些技术手段及科研思路值得国内学习与借鉴。     

探讨泊位利用率数值的确定方法

借助排队论分析某港一期工程的统计资料,确定其港口服务系统的数学特征及主要特征值,探讨选取泊位利用率应考虑的因素,并提出一种确定泊位利用率数值的方法。     

Consumer purchase intentions for electric vehicles: Is green more important than price and range?

In view of global warming and climate change, a transition from combustion to electric vehicles (EVs) can help to reduce greenhouse gas emissions and improve air quality. However, high acquisition costs and short driving ranges are considered to be main factors which impede the diffusion of EVs. Since electricity needs to be produced from renewable energy sources for EVs to be a true green alternative, the environmental performance of EVs is also presumed to be an important factor. This paper investigates the role of environmental performance compared to price value and range confidence regarding consumer purchase intentions for EVs. To develop our hypothesis, we interview 40 end-user subjects about their beliefs toward EVs. Then, we perform 167 test drives with a plug-in battery EV and conduct a survey with the participants to test the hypothesis. Results of a structural equation modeling support the hypothesis that the environmental performance of EVs is a stronger predictor of attitude and thus purchase intention than price value and range confidence.     

城市轨道交通新建线路对沿线住宅价格增值的时空效应

定量分析城市轨道交通对沿线土地价值的影响，是通过土地价值捕获将外部效益内部化， 解决中国新型城镇化过程中城市轨道交通财务可持续的关键问题。本文在开源数据环境下，获 取2011—2016年北京市二手房交易数据，采用特征价格模型(HPM)分析北京城市轨道交通新建 线路对沿线住宅价格增值的时空效应。研究表明：与全局常参数的多元线性回归模型(MLR)、空 间滞后模型(SLM)、空间误差模型(SEM)和空间杜宾模型(SDM)相比，局部变参数的地理加权回归 模型(GWR)拟合效果更优，可以更好地消除残差的空间效应，刻画轨道交通与土地价值关系的空 间异质性。城市轨道交通带来的可达性提升对沿线80%以上住宅小区的房价具有显著的正效 应，住宅价格增值比率随地铁站距离递远递减，且具有显著的空间异质性。轨道交通对住宅价格 的影响在空间上具有网络化效应，新建线路不仅会改变周边房价，对城轨网络其他位置的住宅也 具有影响。城市轨道交通对住宅价格的影响范围为1 km，在该范围内，住宅价格受到的增值效应 在 2011—2016 年基本稳定，约为 3%；受新线直接影响区域的住宅价格会产生相对更大的提升 (0.02%~0.22%)。     

Evaluation of total risk exposure and insurance premiums in the maritime industry

The empirical evaluation of maritime risk exposure is based on the monetary value at risk (MVR) that incorporates individual safety quality data of about 130,000 vessels, insurable values related to various potential damages, and proxies for fractions of values lost at incidents. MVR provides a tool to enhance strategic planning of maritime administrations and insurance providers, which is illustrated by a high level comparison of annual risk exposure with insurance premiums for 2010–2014. The analysis reveals a global annual insurable value of 30.6 trillion USD with associated annual MVR of 38.8 billion USD for very serious and serious incidents. Although oil tankers show the highest risk exposure (1.75 million USD per tanker per year), safety qualities are found to be best for this ship type (1.4% annual incident risk) and worst for container vessels (2.8%). Annual growth rates in total risk exposure are mostly positive with highest value for dry bulk carriers (27.8%), whereas risk exposure tends to decline for pollution of oil tankers (−2.0%) and passenger vessels (−11.3%), and for loss of life of oil tankers (−1.9%) and dry bulk carriers (−1.4%). Comparison across administrative dimensions reveals that most risk exposure lies with old open registries and with beneficial owners and the Document of Compliance companies located in high income countries. Comparison with global insurance premiums suggests reasonably adequate coverage of maritime risks (excluding cargo) with under-insurance of risk by around 5% (about 1 billion USD per year), with some uncertainties remaining for actual loss fractions of the involved damages.     

东京和香港轨道交通站场综合开发启示

在简要介绍轨道交通站场综合开发之必要性的基础上,对轨道交通站场综合开发的基本内涵进行剖析,然后对东京和香港轨道交通站场综合开发的经验做法进行介绍。最后进行经验总结与思考,认为要构建多元主体参与的组织机制,注重公私合作、利益共享、风险共担;通过科学规划和深度捆绑,实现交通规划与土地规划同步推进;确保地铁公司低价拿地,借助特许经营方式,充分享受土地增值收益;梯度开发,对地铁上盖物业进行高强度圈层式开发。