Threshold controlled scheme of difference expansion techniques for reversible watermarking

Since Tian Jun proposed the difference expansion embedding technique, based on which, many reversible watermarking techniques were proposed. However, these methods do not perform well when the payload is high. In this paper, we proposed an expandable difference threshold controlled scheme for these three methods. Experiments show that our scheme improves the performance of these three methods for heavy payload.     

铁路信号设计规范修订说明（之二）

4轨道检查装置部分 本《规范》针对轨道检查装置存在的问题，吸取多年实际应用中的经验教训，对设备使用的环境和条件进行了必要的调整。根据铁道部的现行电务政策，对轨道检查装置的设备选型与应用也做出了必要的规定。     

旋挖钻机在宁波大碶疏港公路延伸段工程中的应用

近年来,旋挖钻机作为一种新型的桩基施工机械由于其效率高、环保等性能已经在我国广泛应用,但一直以来也受到其自重、钻杆长度等限制,在大直径、深孔工程及软土地区使用较少。该工程通过实践,成功的在软土地区使用了旋挖钻机,且最大成孔深度达82m。     

Why are work travel plans effective? Comparing conclusions from narrative and meta-analytical research synthesis

Reliable research synthesis is of high significance for a transport policy which tries to base its decisions on available empirical evidence. There is growing doubt whether the frequently used narrative approach provides a scientifically defensible way of synthesising a body of quantitative research results. The present paper demonstrates meta-analysis as a more objective and powerful alternative for this task. For this purpose evaluation data synthesised in two earlier narrative reviews on the effectiveness of work travel plans [Cairns et al. Making travel plans work: research report (former), Department for Transport, Local Government and the Regions (DTLR), London, 2002; Smarter choices—changing the way we travel. (Final report of the research project: The influence of soft factor interventions on travel demand. Research report for the Department for Transport.) London. Retrieved 1 December 2005, from , 2004] are meta-analytically re-analysed and compared with the conclusions drawn from the narrative synthesis of these data. Our meta-analyis provides only limited support for the conclusion that addressing parking is the hallmark of successful work travel plans. Our meta-analysis indicates that site and organisational factors as well as characteristics of the monitoring process are significant predictors of effective work travel plans, whereas Cairns et al. view little evidence for the impact of these factors.     

Guidelines for samplers: measuring a change in behaviour from before and after surveys

This paper addresses the issue of using before and after surveys to evaluate behavioural changes in response to transport policies and investments, a procedure that, we argue is done far too rarely in this profession. Further, it demonstrates very clearly that, in almost all conceivable cases, there are considerable economies to be obtained by using a panel (again, under-utilised in our profession) to undertake evaluation, rather than successive independent cross-sectional surveys. The paper also addresses the critical issue of sample size requirements for measuring changes of a relatively small magnitude in travel behaviour; i.e., to state, with 95% confidence, that if there is a ∂ percent change in behaviour for the sample, there is a ∂ percent ± e percent change in the behaviour of the population, where e is the sampling error. In this paper, we present a method for calculating such sample size requirements from first principles and demonstrate the applicability both hypothetically and then empirically using data from the Puget Sound Transportation Panel. The formulation enables designers of before and after surveys to investigate the trade-offs between the statistical accuracy of their predictions and the sample size requirements systematically, without the need to specify ∂ a priori. This latter point is crucial, we argue, because we have limited information on ∂, yet, as we explain here, it drives the sample size requirements using alternative, well-cited approaches for calculating sample sizes to assess behavioural change. The results have important ramifications both for those implementing transport policies intended to produce behavioural change, especially when a cost-benefit evaluation of the policy is desired, and for those interpreting the results reported in previous studies.     

不确定网络路径优化模型及算法研究

道路事故、道路施工等突发因素干扰了道路正常运营状态,严重时将造成交通网络的局部阻塞;同时道路使用者感知交通网络环境的变化具有多样性和滞后性.正是因为这些不确定因素的存在,交通网络也呈现出不确定性特征.针对出行时耗需要保障的出行决策优化问题,引入可信性理论体系的测度标准;将路段出行时耗变量模糊处理;构建了在一定显著度水平条件以出行总时耗为优化目标,以出行路径为决策变量的模糊机会约束模型,给出基于模糊模拟的组合优化算法,计算示例表明,模型构建合理,算法有效.     

Climate change and the future Maritime Policy for the EU

A cross-cutting Maritime Policy can ensure that climate change threats and challenges in regards to seas and oceans are dealt with in a wide policy framework that takes into account the impacts that climate change may have on other sectors and vice versa.     

Basic design of a series propeller with vibration consideration by genetic algorithm

Genetic algorithms (GAs) can powerfully search for parameters in a large multidimensional design space. Thus, the principle can be applied to preliminary series propeller design problems with multiple considerations. In the present study, B-series propeller design was conducted using a GA for both hydrodynamic efficiency and vibration consideration. The objective function was set by users who could freely weight the relative importance of efficiency and vibration. GAs were successfully shown to be able to obtain an optimal set of parameters leading to efficient performance and low vibration.     

计算圆舭快艇阻力的一种简便方法

根据排水量长度系数C和排水量纵向分布是影响圆舭快艇静水阻力主要参数的观点,本文对文献国舭快艇阻力试验的系列图谱进行了重新计算和整理后,得出了一组剩余阻力系数C_k=/(C,F_n)曲线图。用此曲线可简单、迅速而比较正确地计算高速国舭快艇的静水阻力,供设计图舭快艇的初始阶段作估算用。 为了使这类艇的阻力性能比较良好,文中还扼要地介绍了一些船型和附体设计的特点供参考。     

威大线客滚船电气设计特点

本文重点介绍了威大线客滚船在电气系统设计中的主要特点。