Long-term prediction method for the green water load and volume for an assessment of the load line

 To develop a practical prediction method for the green water load and volume on the bow deck in irregular waves, model tests were conducted using a tanker and a cargo ship on a domestic Japanese voyage. The relation between green water load and relative water height at the stem was considered. Based on the finding that the maximum value of the green water load is proportional to the square of the maximum value of the water elevation over the bow top, the probability density functions of the green water load and volume in short-term predictions were proposed. It was verified that the proposed functions show good agreement with the measured distributions, especially in the tails, and were better than conventional functions. Using these functions, long-term predictions of the green water load were carried out. It was confirmed that the present method is more rational than the conventional one for estimating the long-term probability of the green water load. An assessment of the bow height of a domestic Japanese ship from the viewpoint of deck wetness was carried out using these prediction methods. This research was used as the technical background for the revision of domestic rules on load lines, which was enforced in October 2001. Received: July 19, 2002 / Accepted: October 30, 2002 Acknowledgment. Some of the present study was carried out as part of a cooperation project (RR45) with the Shipbuilding Research Association of Japan, supported by the Nippon Foundation. Address correspondence to: Y. Ogawa (e-mail: ogawa@nmri.go.jp)     

高速列车通过截面突变隧道时压力波的数值模拟研究

高速铁路隧道压力波是铁路高速化中日益突出的问题之一,而高速列车通过截面突变隧道时压力波特性目前研究较少。本文根据高速列车通过隧道过程中引起空气流动的特点,在对复杂空气流动现象进行合理简化的基础上,采用一维可压缩不等熵非定常流体流动模型和广义黎曼变量特征线法发展了截面突变隧道压力波的数值计算方法,并给出了相应的边界条件,随后与国外典型试验数据进行了比较,证明本方法的正确性。在此基础上本文分别对单车和会车通过截面突变隧道的压力波进行了数值分析,对揭示截面突变隧道内压力波特征及截面突变对隧道压力波的影响有一定的意义。     

Land Changes and Conflicts Coordination in Coastal Urbanization: A Case Study of the Shandong Peninsula in China

The coastal zone is an interaction region between land and ocean and an interface of geosphere, hydrosphere, atmosphere, and biosphere, as well as greatly affected by human activities. Driven by economic activities and increased population, urbanization is rapidly developing in coastal zones, and a series of land resource and environmental conflicts have occurred, especially in developing countries at times of economic transition. This article reports a case study of the Shandong Peninsula of East China. We analyze the land-use practices and land cover changes of six cities over a timeframe of nearly a decade. We then review the management conflict issues. The most commonly encountered conflicts fall into three categories: those between expanding constructed land and decreased cultivated land; those between land resource utilization and conservation; and those between increasing demand for land and degrading land quality. All in all, they reflect the fundamental conflicts between short-term economic development gains and long-term food security and ecosystem sustainability. This article puts forward an institutional approach to coordinate these conflicts so as to realize integrated and coordinated coastal management.     

A demand trend change early warning forecast model for the city of São Paulo multi-airport system

The need of accurate forecasts of air passenger numbers to assist managerial decision making for both short and long terms is well recognized and a central problem on both short and long term forecasting is how to handle future trend. The aim of this paper is to develop a demand trend change early warning forecast model (EWFM) for the city of São Paulo multi-airport system (SPMARs). For SPMARs the EWFM is based on the combination of leading indicators and alarms against possible occurrence of changes on trend component of the monthly number of domestic air passengers. A topdown induction procedure is employed to identify leading indicators to provide an interpretable prediction procedure to support the development of scenarios for future demand trend. Results show that changes on such demand trend are mostly associated to changes on the economic activity and six different scenarios were built combining the identified leading indicators. The EWFM was employed to assist managerial decision making for both short and long terms in order to evaluate different alternatives to prevent congestion delay occurrences and to support infrastructure planning.     

The influence of built environment to the trends in commuting journeys in the Netherlands

In this paper we describe commuting trends in the Netherlands in the past decade and examine the influence of urban form and travel accessibility on commuting journeys over time on the basis of data from the Dutch National Travel Survey. Exploratory analysis is performed to identify changes in commuting participation, departure time, commuting time, commuting distance and the modal split. Regression analysis and choice models are used to examine the influence of the built environment on commuting parameters over time. The results indicate that urban form has consistently influenced the parameters of commuting journey in the Netherlands in the last 10 years. However, the trend of the influence is unique for each commuting model. Some influences have become less significant in the last decade and some have become stronger.

特大断面隧道远程自动监测方案的研究

文章介绍了特大断面隧道——广州龙头山隧道的远程自动监测系统。该系统由本地子系统和远程监测子系统构成,其中本地测量子系统实现了对拱顶沉降、锚杆应力、二次衬砌钢筋应力和二次衬砌混凝土应变四个方面的远程自动监测;无线传输子系统采用基于Web(Internet)及GSM中GPRS的无线远程数据传输方式,实现了对隧道监测数据的远程无线传输。根据7个月监测可知,龙头山隧道使用正常,各部分结构处于安全状态。为评价特大断面隧道结构的长期安全性,还需要在今后的运营阶段做更长时间的监测及提供更多的数据支持。     

城市轨道交通项目竣工环保自主验收主要问题研究

建设项目竣工环保验收由生态环境部门负责调整为建设单位自主验收后,分析城市轨道交通行业竣工环保验收可能面临的重大变动未履行环评程序、环保措施弱化引起居民投诉、验收标准复杂难选、文物和历史建筑保护要求各异、施工期环境影响大、责任主体转换后面临监管加强等主要困难和问题,并从提高行业竣工环保自主验收质量的角度,指出建设单位应充分认识自身的环保责任主体,加强施工期环境管理,对照新标准要求提前做好应对及防护,及时解决居民的合理环保诉求,开展跟踪研究和环境影响后评价。     

浅谈大学生党员如何保持先进性

大学生党员保持先进性对于党和国家事业的发展具有深远的历史意义,他们应当紧密联系自身的实际,增强与时俱进、求真务实、责任服务的意识;努力加强理论学习、专业学习、思想修养,不断提高觉悟、增强本领和提升人生境界。同时,还应当创新思路出发,努力形成大学生党员保持先进性教育的长效机制。     

NPY神经纤维在大鼠心脏的分布及增龄变化

用免疫细胞化学ABC法在光镜和电镜下观察了不同月龄组SD大鼠心脏神经肽酪氨酸(NPY)神经纤维的分布特征及其衰老变化。结果发现:心脏各部位、各结构具有不同密度、不同形式的NPY神经分布,纤维均为膨体型。电镜下,神经纤维行于心肌间隙并与心肌细胞贴近,轴浆内充满NPY阳性反应颗粒。随月龄增加,神经纤维密度下降,纤维形态及分布形式发生改变,对心脏支配减弱。此外,在心内还发现NPY神经节。     

LTE-U在城市轨道交通中的应用研究

随着LTE在城市轨道交通中的推广应用,授权频谱资源不足与城市轨道交通车地间数据传输需求的矛盾制约着车地无线通信系统建设方案的选择,利用非授权频谱实现LTE的LTE-U新兴无线技术有望缓解甚至解决该问题。通过对LTE-U的技术研究,分析其在城市轨道交通应用中的技术优势：移动和切换性能优异、传输时延小、抗干扰能力强、覆盖半径大、QoS保障好、安全性高、可靠性高等特点。通过搭建LTE-U测试网络,在实验室进行120 km/h、140 km/h、160 km/h典型速度下加载CCTV和PIS业务测试;在80 km/h城市轨道交通线路上,采用 A、B冗余组网测试,A网承载CBTC业务,B网综合承载CBTC、CCTV和PIS业务;选择在80～170 km/h的速度下搭建LTE-U网络,并进行CCTV和PIS业务测试。测试结果显示,LTE-U具有对城市轨道交通CBTC、CCTV、PIS业务的承载能力。同时,LTE-U在城市轨道交通的应用仍面临诸多挑战,如LAA技术的TAU有待开发、Standalone技术的多载波聚合产品不成熟以及其他非授权频谱产品的竞争等,最终提出在城市轨道交通中部署LTE-U的建议。