The marine electronic highway in the Straits of Malacca and Singapore—an assessment of costs and key benefits

The Straits of Malacca and Singapore are an important trade route linking the Indian Ocean to the South China Sea and Pacific Ocean. They are also rich in resources and support a range of activities that benefit the economies of the littoral states (Indonesia, Malaysia and Singapore). This important shipping route is a very congested waterway and the authorities are keen to improve navigation facilities to promote ship safety and reduce the risk of groundings, collisions and accidents. This will also help to protect the marine environment from the effects of pollution and hence reduce its damaging impact on activities related to the Straits, e.g. fisheries and tourism. The Marine Electronic Highway (MEH) is an attempt to bring together maritime safety technologies and environmental management systems. The paper examines the costs of providing such a highway and considers some of the benefits which could accrue from its implementation. The analysis, conducted in the form of a cost-benefit study, clearly shows the economic viability of the scheme.     

乌鞘岭隧道千枚岩大变形段平导扩挖爆破有关影响分析

乌鞘岭隧道设计为2座平行的单线隧道,线间距40 m。介绍DK175+503~DK177+042段平导扩挖爆破对已建成的相邻工程的爆破振动及变形影响。     

考虑抗剪强度指标互相关性的边坡可靠度分析

根据已有研究：C、(?)的互相关性对边坡整体稳定可靠度指标的影响是显著的,因此在计算边坡稳定失效概率时要充分考虑其互相关性。为了更真实的了解在应用设计验算点法研究Bishop条分边坡的整体稳定时土性参数C、(?)之间的互相关性,本文将土的抗剪强度指标C、(?)看作随初变量,并服从正态分布。在工程中极限状态方程往往很复杂,不易直接代入方程求解,因此本文给出了直接迭代公式,并且结合实例验证了其精度。     

PC箱梁桥裂缝成因及防治对策

针对PC箱梁桥在施工或使用中混凝土出现开裂的情况，将裂缝分为“荷载裂缝”和“变形裂缝”两大类，分析了裂缝的特征及成因，提出了防治对策。     

方中空夹层钢管混凝土轴压构件的理论研究

在确定了钢材和混凝土本构关系模型的基础上,采用数值方法,对方中空夹层钢管混凝土轴压构件的荷载—变形关系曲线进行了计算,计算结果和试验结果吻合良好。     

基于融合技术的计算机网络安全

网络攻击手段的多样化，不仅给网络安全与管理提出了新的挑战，而且对网络创新安全理论，整合各种安全解决方案，构建综合的动态网络提出了更高的要求。重点讨论了不同安全产品的融合和安全产品与网络设备的融合。     

A high order linear model for the prediction of internal lee waves at the main sill of the Strait of Gibraltar

A linear theory for the physical fields in the water column under the action of large amplitude internal lee waves at the main sill of the Strait of Gibraltar is developed. The procedure is a combination of the perturbation and normal modes methods in order to study steady resonant conditions. The lowest order linear approach of the methodology resumes the Taylor–Goldstein equation, which can reconstruct the main features of the observed fields but the high order approach gives the finest structure and sometimes the largest contributions. The role of the non-linear terms is investigated up to the second order taking into account the non-linear interactions between modes, leading to an effective reconstruction of the whole water column for the velocity field.     

Estimation of origin‐destination matrices for a multimodal public transit network

This paper presents a procedure for the estimation of origin‐destination (O‐D) matrices for a multimodal public transit network. The system consists of a number of favored public transit modes that are obtained from a modal split process in a traditional four‐step transportation model. The demand of each favored mode is assigned to the multimodal network, which is comprised of a set of connected links of different public transit modes. An entropy maximization procedure is proposed to simultaneously estimate the O‐D demand matrices of all favored modes, which are consistent with target data sets such as the boarding counts and line segment flows that are observed directly in the network. A case study of the Hong Kong multimodal transit network is used to demonstrate the effectiveness of the proposed methodology.     

关于漏解问题的探讨

“N 1”改造后,有关出发进路末端道岔区段漏解锁问题的探讨。     

A traffic flow simulator for short‐term travel time forecasting

This paper presents an off‐line forecasting system for short‐term travel time forecasting. These forecasts are based on the historical traffic count data provided by detectors installed on Annual Traffic Census (ATC) stations in Hong Kong. A traffic flow simulator (TFS) is developed for short‐term travel time forecasting (in terms of offline forecasting), in which the variation of perceived travel time error and the fluctuations of origin‐destination (O‐D) demand are considered explicitly. On the basis of prior O‐D demand and partial updated detector data, the TFS can estimate the link travel times and flows for the whole network together with their variances and covariances. The short‐term travel time forecasting by O‐D pair can also be assessed and the O‐D matrix can be updated simultaneously. The application of the proposed off‐line forecasting system is illustrated by a numerical example in Hong Kong.