船舶三维数字化设计研究

对船舶三维设计方法及技术进行了研究,阐述了基于CATIA的船舶三维设计具体设计流程和方法,并结合3100TEU集装箱船具体实例,探讨了船舶三维设计方法和一般步骤.该研究对船舶三维设计系统的开发有一定参考价值。     

桥梁抗震设计方法综述

本文介绍了目前用于桥梁抗震设计的主要设计方法,并通过对其各自理论根源的分析,详细介绍了各种方法的优缺点和使用条件,为在今后的抗震设计中选择合适的设计方法提供了依据。     

多学科设计优化:载人潜水器设计的一种新工具

多学科优化作为一种新的设计方法,已经成功地应用在很多领域,如飞机制造,太空船,汽车制造等.传统的载人潜水器设计并不是一种最优的设计方法,并且在载人潜水器的设计过程中所要涉及多种技术学科.将多学科优化方法引进载人潜水器的设计,从而可以实现真正的设计优化.本文介绍了多学科优化的基本理论和方法,整体构架,并介绍了探索设计空间的算法.在对多学科优化设计方法理解的基础上,提出了在载人潜水器设计中如何应用的初步考虑.     

桨后整流支架的设计方法

简要分析了桨后整流支架的特点及其一般设计原则,以及基于动量理论、叶素理论和理想螺旋桨理论阐述了桨后整流支架的设计方法,最后给出了一个基于该设计方法的设计实例,并将本设计方法的计算结果与试验结果进行了分析比较,进一步验证了该方法的可行性。     

BIM技术在集装箱港区室外电气管线设计中的应用

针对传统集装箱港区电气室外管线设计存在的问题,提出了基于BIM技术的新设计方法。依托实际集装箱港口工程项目,结合集装箱港区室外管线的设计要点,采用基于BIM的三维设计方法,利用Revit等三维设计工具,详细阐述了整个设计过程,并对BIM设计方法的输出成果与传统设计方法的输出成果进行了对比分析,得出了BIM设计方法的优点。据此,为集装箱港口工程中的电气室外管线详细设计提供一种新的三维设计方法和相应的技术路线,以改善传统设计方法的不足。     

以Petri网为描述工具的分布式数据库系统研究

研究了分布式数据库的各种设计方法,在此基础上,结合分布式数据库设计方法特点、Petri网理论、面向对象技术和抽象数据类型理论,给出了一种以Petri网为描述工具的分布式数据库设计的实用工具设计方法,并详细论述了其设计过程和实现方法。同时,面向实际应用,采用自顶向下分析方法,完成了需求分析、关系模式的规范化和数据分片、分布等工作,最终向用户提供一套合理的分布式数据库设计方案。     

多学科设计优化方法的比较

为了推广多学科设计优化方法在船舶和海洋工程结构设计中的应用,讨论了三种典型的多学科设计优化方法:多学科可行方向法(MDF),协同优化方法(CO),两级系统综合方法(BLISS),并将其应用到齿轮减速箱的设计中;根据计算结果,对上述三种多学科设计优化方法进行了定量的比较和研究,得出BLISS方法最适合齿轮减速箱优化设计的结论.此外,还给出了多学科设计优化方法的选择标准,为多学科设计优化的工程应用提供了一定的指导和帮助.     

基于iSIGHT的UUV优化设计平台

水下航行体(UUV)外形设计的优劣对UUV的最终性能有着举足轻重的影响。传统的设计方法是通过反复的选型-计算-修改来实现的,这种方法不但效率低下,而且由于选型范围有限,常导致得不到最优解。为解决这一问题,本文研究了UUV的参数化设计方法,并通过自编程序实现了在SolidWorks中的参数化建模。利用iSIGHT优化设计平台强大的过程集成能力和各种寻求最优参数的技术,实现了iSIGHT集成并驱动SolidWorks,Gridgen,CFX等软件并寻求最优参数的设计流程。并针对某UUV,以最小阻力为目标,利用NLPQL优化算法进行了优化设计。结果表明,本设计平台达到了实现UUV参数化设计并优化的目的,提高了设计效率。     

舰船计算机测控系统中的软件冗余方法研究

简要介绍了在舰船计算机测控系统中的软件冗余设计.在设计中采用智能故障诊断和容错技术的设计线路、技术途径、技术方法及避错、容错软件编写的一些原则.主要研究了恢复块及多版本程序设计2种常用的软件冗余设计方法,并就其在分布式系统中应用存在的问题进行简要的分析,提出了软件冗余设计的实际应用,并给出其具体改进方案的设计.     

基于Inventor＆ANSYS Workbench的斗轮堆取料机关键零部件的协同设计

论述在Inventor和ANSYSWorkbench环境下斗轮堆取料机关键零部件协同设计的基本原理,研究协同设计的方法,并针对设计过程中容易出现的问题提出了有效的解决方法。     

船舶制造技术成熟度评估系统

在船舶制造中,技术成熟度的评估意识薄弱且缺少信息化手段。通过确定评估指标、设定权重,建立船舶制造技术成熟度评估系统,由系统计算成熟度的得分和等级,从总体设计、建造工艺、船厂建造资源能力、船舶研制定型后等方面进行评估。该系统可减少返工带来的时间成本、人力成本,提高船舶制造技术成熟度评估的科学性、准确性、可靠性、灵活性及效率。     

How much can public private partnership really do for urban transport in developing countries?

A few cities in some of the larger developing countries in Latin America and Asia have made increasing use of multi-year concessions or franchises, competitively awarded to private companies, for construction and operation of urban transport infrastructure and for provision of public transport services. In view of the strong prospective growth of developing-country cities with large transport needs, and the rise in the emerging economies of potential new sources of private capital, it is important to see how effective PPP has so far been in this area. The experience is analyzed principally by thorough comparative review of what has actually happened for some of the main users to date: Bogotá, Santiago, São Paulo, Seoul, and several cities in both China and India. Despite delays and mistakes that have been made in development of most of the projects, the overall results, already delivered and in prospect, are very positive and urban public transport is benefiting substantially, with significant side effects on poorer people's access to work and to services, air pollution levels and road accident rates. The widest and most important advantage of the PPP arrangements, as compared with more conventional short-term contracting, is found to be the innovations, technical and managerial, developed, and, in particular, the mutual capacity building of the countries' private and public sectors and their more effective interaction. The experience in the six countries covered suggests that other developing-country cities may be best assisted to develop sound urban transport PPPs more rapidly through provision of help on chosen items among 7 elements that have proved particularly crucial but sometimes weak in the projects reviewed: Civic consultation systems, Land-use/Transport strategic planning, Land/property market management, Monitoring systems, Progressive policies, Economic regulation, and Public institutional framework for PPPs.     

高铁酸钾的制备与应用研究

高铁酸钾集氧化、杀菌、吸附、絮凝、脱色、除臭等多功能于一体,是一种绿色氧化剂。本文综述了高铁酸钾的制备方法,包括氯酸盐氧化法、电解氧化法和过氧化物高温氧化法,讨论了其溶解性和稳定性,并重点介绍了其在污水处理、毒剂洗消、生物消毒等方面的应用研究,展望了其研究趋势和广阔的应用前景。     

Towards a seascape typology. I. Zipf versus Pareto laws

Two data analysis methods, referred to as the Zipf and Pareto methods, initially introduced in economics and linguistics two centuries ago and subsequently used in a wide range of fields (word frequency in languages and literature, human demographics, finance, city formation, genomics and physics), are described and proposed here as a potential tool to classify space–time patterns in marine ecology. The aim of this paper is, first, to present the theoretical bases of Zipf and Pareto laws, and to demonstrate that they are strictly equivalent. In that way, we provide a one-to-one correspondence between their characteristic exponents and argue that the choice of technique is a matter of convenience. Second, we argue that the appeal of this technique is that it is assumption-free for the distribution of the data and regularity of sampling interval, as well as being extremely easy to implement. Finally, in order to allow marine ecologists to identify and classify any structure in their data sets, we provide a step by step overview of the characteristic shapes expected for Zipf's law for the cases of randomness, power law behavior, power law behavior contaminated by internal and external noise, and competing power laws illustrated on the basis of typical ecological situations such as mixing processes involving non-interacting and interacting species, phytoplankton growth processes and differential grazing by zooplankton.     

Matching biological traits to environmental conditions in marine benthic ecosystems

The effects of variability in environmental conditions on species composition in benthic ecosystems are well established, but relatively little is known about how environmental variability relates to ecosystem functioning. Benthic invertebrate assemblages are heavily involved in the maintenance of ecological processes and investigation of the biological characteristics (traits) expressed in these assemblages can provide information about some aspects of functioning. The aim of this study was to establish and explore relationships between environmental variability and biological traits expressed in megafauna assemblages in two UK regions. Patterns of trait composition were matched to environmental conditions and subsets of variables best describing these patterns determined. The nature of the relationships were subsequently examined at two separate scales, both between and within the regions studied. Over the whole area, some traits related to size, longevity, reproduction, mobility, flexibility, feeding method, sociability and living habit were negatively correlated with salinity, sea surface temperature, annual temperature range and the level of fishing effort, and positively associated with fish taxon richness and shell content of the substratum. Between the two regions, reductions in temperature range and shell content were associated with infrequent relative occurrences of short-lived, moderately mobile, flexible, solitary, opportunistic, permanent-burrow dwelling fauna and those exhibiting reproductive strategies based on benthic development. Relationships between some traits and environmental conditions diverged within the two regions, with increases in fishing effort and shell content of the substratum being associated with low frequencies of occurrence of moderately mobile and moderately to highly flexible fauna within one region, but high frequencies in the other. These changes in trait composition have implications for ecosystem processes, with, for example, reductions in permanent-burrow dwellers within one of the regions potentially compromising the ability of the assemblages to process and store chemicals and waste products. However, the connections between environmental conditions and trait composition are complex and incorporate many factors. Experimental investigations will be necessary to determine the extent and consequences of these important relationships.     

A Review of Whale-Watching and Whaling with Applications for the Caribbean

Whale-watching is a significant and growing tourism industry worldwide. Whaling has a long history and, although largely curtailed today, still occurs in a few countries around the world and in the Caribbean. Whaling has been labeled an incompatible activity with whale-watching because, in some cases, it reduces the number of whales available for use and changes whale behavior. Moreover, in some situations, whale-watching generates greater revenue than whaling, and whaling may detrimentally affect the larger tourism industry because of negative attitudes toward whaling by whale-watchers, other tourists, and host communities. This article examines the potential impacts of whaling on the whale-watching and tourism industries, and places these impacts in the Caribbean context. In doing so, the article outlines the history and current status of whale-watching in the Caribbean, outlines other potential constraints, and highlights the need for research about the impacts and roles of these industries. In the highly competitive global tourism industry, maintaining and nurturing a country's tourism image is critically important.     

旋转机械状态振动监测与故障诊断系统

旋转机械状态振动监测和故障诊断技术主要包括振动监测、振动信号处理和分析、故障诊断等．针对这些特点,以Windows2000及WindowsXP为开发平台,采用LabVIEW及MAT—LAB为编程工具,综合计算机技术、虚拟仪器技术、信号处理技术与故障诊断等技术,开发了一套旋转机械状态振动监测与故障诊断系统．该系统可以实现对振动信号的多通道采集、存储,实现离线、在线信号的时域、频域、幅值域、时频域分析处理;配置独立的小波分析模块,可以实现存储信号的小波消噪、小波包分解、发展趋势识别等功能．同时,还可实现对旋转机械故障的早期监测与其常见故障的诊断等功能．     

基于支持向量机的模式识别方法研究

本文对支持向量机的原理和应用进行了综合论述。首先,概要叙述了支持向量机(SVM)的产生背景和发展前景。简要介绍了SVM的定义、分类及算法。最后,对SVM在文本识别、数字识别、人脸检测、人脸识别、人脸认证、回归分析及预测、图像检索、特征提取等方面的应用进行了讨论。     

A comparison of rail liberalisation levels across four European countries

This paper presents the results of a research into railway regulation and liberalisation in Italy, France, Germany and Spain. The analysis covers the relationship between the State and the rail companies, network access conditions by operators, slot allocating and pricing schemes and how public service obligations are defined, financed and regulated.