The market for second-hand ships: Further results on efficiency using cointegration analysis

This paper examines the dynamic behaviour of second-hand prices of tankers and dry-cargo vessels over various time periods, with a view to determining whether or not the markets for such assets are efficient. It extends and re-analyses the results of an earlier study by Hale and Vanags, published in this journal in 1992. Using a more modern method of testing for cointegration, it is shown that both the tanker and dry cargo markets appear to be cointegrated, a fact which would suggest that these markets are inefficient. It is suggested that the existence of cointegration does not necessarily imply market inefficiency, if the factors that create the common trends are themselves stochastic in nature. With this in mind, it is argued that the evidence put forward in this paper is still consistent with market efficiency in the long run.     

高压脉冲轨道电路的维护与故障处理

简述脉冲轨道电路日常维护需注意的地方;根据故障处理经验,编制出通过测试数据,查找出故障原因的程序。     

振动压路机起振过程分析

运用机械系统虚拟样机软件ADAMS建立了振动压路机激振器的虚拟样机，并利用其进行了振动压路机起振过程的仿真研究，分析了液压系统压力对启动过程中档销受力及对动偏心块和固定偏心块运动学参数的影响。     

强化单车核算降低装卸成本

1 问题的提出 单车成本是指每台机械在使用过程中所发生的所有费用的总和.主要包括机械日常维修保养费用、机械大修理费用、动力燃料费用和技术改造费用等.对装卸机械实行单车成本核算及考核,就是制定合理的考核指标和考核办法,将每台机械在使用过程中所发生的所有费用的总和定期进行汇总、统计,并与考核指标对比,进行奖惩兑现,用经济杠杆制约人的行为,从而达到降低装卸成本的目的.     

Gain and noise figure analysis of Er<Superscript>3+</Superscript>-doped YAG transparent ceramic microchip amplifier

The rate equations and the power evolution equations based on excited state absorption (ESA) and cooperative upconversion (CUC) of high concentration erbium-doped yttrium aluminum garnet (YAG) transparent ceramic waveguide amplifier are set up to analyze the effects of the pump power, active ion concentration and waveguide length on the amplifier gain and noise figure (NF). The numerical analysis predicts that with a pump power of 100mW, an active ion concentration of 1.0×10²⁶ ion/m³ and a waveguide length of 3 cm, a small-signal gain of 30 dB and an NF of 5 dB can be achieved in the micro-chip amplifier.     

Ontario cottager associations and shoreline management

Abstract

Growth in the number of cottager, or lake property owner, associations in Ontario has been rapid. Cottager associations attempt to address directly, and influence government decision‐making on, issues affecting shoreline management and the recreational experience of cottagers. However, associations infrequently resolve these issues to their satisfaction. A questionnaire and case study show that the nature of the issue, human and financial resources available to the association, and the nature of the decision‐making process affect the extent to which associations influence outcomes. Unreceptiveness of government officials to association participation in decision‐making and confused agency jurisdictions over shoreline resources appear to inhibit association effectiveness. Concerns about the status of shoreline management in Ontario and public participation in decision‐making are raised.     

Development of a hull form definition tool with a related knowledge-based advisory system

The development of a parametric hull form design system utilizing combined knowledge-based and objectoriented methodologies, approaches, and techniques is the major purpose of this research. One objective was the development of a powerful, intuitive, and parameter-based hull definition system with a related hull definition advisory system that would provide useful and necessary advice to the user. Object and knowledge modeling activities were conducted during the analysis and design stage to facilitate the implementation of a hull design program and advisory system. The hull design system includes the generation of a geometric model from a process of aggregating simple user-selected shapes representing different boundaries. Design involves the capability to vary simple parameters such as entrance angles, length-breadth ratios, and radii to define local and general surface geometries. Hydrostatic calculations are included for analysis; results are referred to an advisory system for evaluation and the determination of the acceptability of parameters and analysis results. The advisory system includes a knowledge bases consisting of hull form databases, results of the statistical analysis of data, design parameter constraints, and expert knowledge acquired from designers, reference materials, and technical reports. Use of the design tool with the advisory system results in the rapid generation of hull forms and associated design evaluations. Flexibility in decision making results from the separation of the design system from the advisory system. The independence of the two systems allows for a wide range of user experience with experts using the design tool with minimal reference to the advisory system. On the other hand, the expertise and knowledge stored in the advisory system is fully available to inexperienced designers and users.     

Study of the helicopter blade running elevation measurement system

Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter＇ s security and other performance capabilities. In testing, however, it has been difficult to measure the elevation when the rotor reaches high speeds. To get a simple, fast and highly accurate measurement system, photo electricity technology was applied to measuring the blade running elevation. Discussed is the measurement principle of blade running elevation, tire design of the measurement system and analysis of the measurement precision.     

移动模架造桥机在苏通大桥引桥PC连续梁的应用

介绍了苏通北引桥完全自行式移动模架系统的一般构造及工作原理。重点分析了移动模架系统施工过程中箱梁底板线形控制要点及箱梁悬臂段受力特点，针对悬臂端箱梁底板横向应力水平过高的特点，揭示了原因，提出了工程措施并在实桥中应用。