大城市道路交通管理之警务方法——新加坡道路安全教育的经验

通过梳理新加坡在建立道路安全、文明环境方面的不同举措,全面展现新加坡在提升道路安全方面的经验。所有这些新举措共同构成了"更安全的新加坡道路"行动计划,提出"每个生命都很重要"的宗旨,一个生命的陨落都显得太多。这些举措基于交通警察局针对道路安全提出的三管齐下的方法而形成,包括执法、参与和教育,通过这些举措新加坡的交通死亡率在过去10年逐渐降低。自从2013年实施这一行动计划,新加坡道路死亡率得到遏制。未来,面临运营环境的不断挑战,交通警察局将持续追求低道路死亡率的目标并确保道路安全。     

Taxi vacancy duration: a regression analysis

Taxi vacancy duration is a major efficiency measure for taxi services. A clear understanding of the various factors and their effect on vacancy duration is necessary for the optimal operational management of taxis. Previous research has only dealt with vacancy duration by assuming probability distributions and has not investigated heterogeneity in the data caused by various factors. We develop a parametric duration model using not only new operational characteristics but also variables associated with taxi demand, such as weather, land use, demographics, socioeconomic variables, and accessibility of public transportation. The model is applied to a large-scale New York City (NYC) taxi trip dataset that covers operations for 2013. The results show that all the attributes have significant associations with vacancy duration that follows a log-normal distribution. Our study is expected to help improve the efficiency of taxi operations by decreasing the time spent in vacant states.     

鼓式制动器结构模态分析

采用试验模态分析和有限元计算模态分析相结合的方法，对鼓式制动器进行模态参数识别，以有限元计算模态分析为主，通过试验模态分析对有限元计算结果进行检验，这种方法是工程上比较实用和行之有效的模态分析方法，针对鼓式制动器各子系统建立了有限元模型，采用动画显示来观察各阶段态的振型，很好地解决了有限元的后处理问题。     

Preview-Based Control of Suspension Systems for Commercial Vehicles

An active suspension with preview is developed for the rear axle of a commercial vehicle. The obtained improvements are promising and justify further investigation of the more feasible semi-active suspensions with preview. The inherent non-linearity of semi-active suspensions with switching shock absorbers and the need for controllers that can handle a broad class of control objectives has led to the development of several numerical control methods for both multi-level and continuously variable shock absorbers. The most promising control method and shock absorber type are selected and mounted in a test vehicle. Some first experimental results are discussed.     

丙型肝炎病毒非结构蛋白3全长基因的克隆和表达

目的克隆和表达丙型肝炎病毒(HCV)非结构基因NS3,为进一步研究其基因功能奠定基础。方法设计特异性引物,以HCV全长cDNA质粒为模板进行PCR扩增,获得全长NS3基因。将其插入克隆载体pMD18-Tvector中,经酶切、PCR及测序鉴定后,与表达载体pET32a重组,后转入BL21菌株并诱导表达。采用SDS-PAGE电泳及Western-blot检测NS3基因的蛋白表达水平。结果含有NS3的重组体构建成功并在大肠杆菌中表达。结论运用原核细胞基因工程技术成功构建和表达了HCV非结构基因NS3蛋白,为尽一步研究HCVNS3基因功能奠定了基础。     

THE CHANGES OF BONE VOLUME AND TURNOVER IN POSTMENOPAUSAL WOMEN WITH OSTEOPOROSIS：A REPORT OF 293 BONE BIOPSIES

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REGULATED PHOSPHORYLATION OF THE GATA－2 DNA BINDINGPROTEIN IN ENDOTHELIAL CELLS

ＲＥＧＵＬＡＴＥＤＰＨＯＳＰＨＯＲＹＬＡＴＩＯＮＯＦＴＨＥＧＡＴＡ－２ＤＮＡＢＩＮＤＩＮＧＰＲＯＴＥＩＮＩＮＥＮＤＯＴＨＥＬＩＡＬＣＥＬＬＳＢｕＸｉｎＥ．Ｅ．Ｑｕｅｒｔｅｒｍｏｕｓ，Ｔ．Ｑｕｅｒｔｅｒｍｏｕｓ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｄｉｃｉｎｅ...     

On the structure of weekly activity/travel patterns

Understanding the process of activity scheduling is a critical pre-requisite to an understanding of changes in travel behavior. To examine this process, a computerized survey instrument was developed to collect household activity scheduling data. The instrument is unique in that it records the evolution of activity schedules from intentions to final outcomes for a weekly period. This paper summarizes an investigation of the structure of activity/travel patterns based on data collected from a pilot study of the instrument. The term “structure” refers to the sequence by which various activities enter one’s daily activity scheduling process. Results of the empirical analyses show that activities of shorter duration were more likely to be opportunistically inserted in a schedule already anchored by their longer duration counterparts. Additionally, analysis of travel patterns reveals that many trip-chains were formed opportunistically. Travel time required to reach an activity was positively related to the scheduling horizon for the activity, with more distant stops being planned earlier than closer locations.     

Optimizing the transportation of international container cargoes in Korea

This paper considers a multimodal transportation problem, which is the problem of determining the transportation flow, i.e. volume of container cargoes, and the transportation mode in each trade route, for the objective of minimizing the sum of shipping and inland transportation costs. The problem takes account of two restrictions: maximum cargo volumes capacitated at each seaport and maximum number of vehicles available at each transportation mode. To solve optimally the problem, this paper employs a mixed integer programming, which is an operations research technique. A case study is performed on the container cargo data in Korea and we draw several implications to improve efficiency in the transportation of international trade cargoes in Korea.     

Automatic FE modeler using stiffener-based mesh generation algorithm for ship structural analysis

Shipbuilding industries have started to employ 3D CAD systems to integrate all design and production processes by achieving seamless data transfer and data sharing. The emerging 3D CAD system brings a considerable change in FE analysis field. The availability of 3D geometry increased the recognition of the need for developing automatic FE modeling system consequently.

However, general automatic mesh algorithms developed by academic research field have a limitation. The difficulty in satisfying lots of line constraints and the absence of proper idealization of 3D geometry entities defined in CAD system hinders directly employing the general mesh algorithms.

In this research, an automatic FE modeling system has been developed for cargo hold FE modeling and whole ship FE modeling. The basic concept of the algorithm is to decompose surfaces using stiffener lines into subregions and generate mesh using a rule established based on FE modeling practice of ship structure. Since the decomposed subregions take simple polygon, they can be easily transformed into elements by decomposing the polygon according to the rule defined considering the shape of the polygon and mesh seed on its perimeter. The algorithm is also designed to treat appropriate geometry idealizations for bracket-type surface and stiffener connections. The idealization process is also completely customized based on FE modeling practice. The validity of the developed system is verified through illustrative examples.