分布式虚拟环境中分级兴趣管理研究

分布式虚拟环境中，分级兴趣管理技术虽能进一步减少负载，但却会增加数据的发送量。为此，提出了一种分级兴趣管理的网络通信方法，当需要同时对高、低兴趣实体集发布数据时，该方法只需从整个兴趣实体集所对应的多播地址发布一个数据包即可。仿真结果表明，与传统分级兴趣管理技术相比，它可以减少数据的发送量,且实现非常简单。     

LY12铝合金搅拌摩擦焊工艺研究

对LY12铝合金进行了搅拌摩擦焊接工艺试验,并对焊接接头进行了金相观察和力学性能检测.试验结果表明,合理的焊接参数匹配是取得性能优良焊接接头的前提.当旋转速度为905 r/m in、焊接速度为33.6 mm/m in、肩部压力为48MPa时施焊,可获得成型良好无缺陷焊接接头,且焊缝区晶粒细小.搅拌摩擦焊焊接轧态LY12铝合金时,焊接时的热输入可部分消除接头处金属的冷作硬化.随着焊接速度的提高,焊接热输入量降低,消除冷作硬化的能力减弱,焊接接头抗拉强度提高.     

车桥回转件CAPP系统中零件信息的输入

零件信息输入是CAPP系统中的一个关X技术问题。本文介绍了一个基于AUt0CAD环境下开发的零件信息输入方法一特征形京法，对商品化CAD环境下实现CAPP信息输入作了一些探讨。     

基于小波变换的图像融合算法研究

提出了一种新的基于小波多尺度分解的分层图像融合方法；总结出基于小波分解子图像面积比和低频系数均方根误差2个标准，来确定最佳小波分解层数的方法。通过仿真实验，对分解层数、区域大小对该融合方法的性能影响进行了比较分析，并得出融合结果，将其与金字塔算法融合结果进行了比较。实验结果表明，该融合方法是十分有效的。     

New applications of EXIT chart for iterative decoding systems

Applications on iterative control and multiple input multiple output （MIMO） system were developed. Two new charts derived from extrinsic information transfer （EXIT） chart were employed as the designing tools, which are called as output mutual information chart with defined iterative degree （DID） chart and near optimum output mutual information （NOMI） chart respectively. Different from the EXIT chart, they can show the iterative performance on the whole signal-to-noise ratio range with one single curve, whereas computation complexity is greatly reduced compared with conventional bit error ratio （BER） performance curve. The iterative control was implemented according to a near-optimum iterative degree vector determined by NOMI chart, the reasonability of uncertain parameters was analyzed in one MIMO system. The concepts were illustrated based on bit-interleaved coded modulation with iterative decoding （BICM-ID）.     

A method for solving the multi‐objective transit frequency optimization problem

Frequency setting takes place at the strategic and tactical planning stages of public transportation systems. The problem consists in determining the time interval between subsequent vehicles for a given set of lines, taking into account interests of users and operators. The result of this stage is considered as input at the operational level. In general, the problem faced by planners is how to distribute a given fleet of buses among a set of given lines. The corresponding decisions determine the frequency of each line, which impacts directly on the waiting time of the users and operator costs. In this work, we consider frequency setting as the problem of minimizing simultaneously users' total travel time and fleet size, which represents the interest of operators. There is a trade‐off between these two measures; therefore, we face a multi‐objective problem. We extend an existing single‐objective formulation to account explicitly for this trade‐off, and propose a Tabu Search solving method to handle efficiently this multi‐objective variant of the problem. The proposed methodology is then applied to a real medium‐sized problem instance, using data of Puerto Montt, Chile. We consider two data sets corresponding to morning‐peak and off‐peak periods. The results obtained show that the proposed methodology is able to improve the current solution in terms of total travel time and fleet size. In addition, the proposed method is able to efficiently suggest (in computational terms) different trade‐off solutions regarding the conflicting objectives of users and operators. Copyright © 2017 John Wiley & Sons, Ltd.     

EDITORIAL: FINANCIAL CREATIVITY

This paper sets out the developments in world shipbuilding policy that have occurred in the past decade. It reviews and outlines the situation that existed in the late 1990s, when an Organization for Economic Co-operation and Development (OECD) agreement on the elimination of shipyard operating subsidies was tantalisingly close. After the Introduction, the second section provides a brief review of the development of the industry over the past three decades, setting the context for developments since 1997. The third section discusses the complaint of the European Union (EU) to the World Trade Organization (WTO) concerning the Republic of Korea's support for its shipbuilding sector, and its counterclaim over the EU's temporary defence mechanism (TDM). It is argued that the core of the EU's case at the WTO was flawed, and that the reintroduction of an operating subsidy via the TDM was a mistake. The only prospect for regularizing competition in this area lies in the negotiation of the OECD agreement that was completed, but not ratified, in 1994. Given the souring of relations between two of the main players in this area, the prospects for such a settlement seem remote. The fourth section uses Olson's theory of groups to argue that the European Commission's actions were driven primarily by industry pressure groups, and failed to consider the potential views of other European stakeholders, in particular the taxpayers. Given the failure of the EU's action at the WTO, the future direction of European shipbuilding policy will have to focus on strategies for internal development and improved industrial competitiveness.     

多元信息预警系统在头道穴隧道施工过程中的安全评价方法研究

为了解决一般安全评价方法单一性、滞后性以及易受人为主观影响的问题,借助多元信息预警系统实测资料,分析了以往公路隧道施工事故原因,在对传统安全评价方法研究的基础上,结合多元信息预警系统工作机制以及在头道穴隧道施工中的应用,提出了一种隧道施工过程的安全评价方法。随着多元信息预警系统在隧道施工过程中的自动采集和监测,构建的评价方法可以将复杂的风险因素及时转化为直观的安全评价结果,同时能够指出具体风险源,最大限度地保障隧道施工安全。     

浅述多工位压力机模具设计要点

针对多工位自动压力机的快速发展,对多工位自动压力机模具进行了研究,介绍了多工位自动压力机模具设计中面临的问题和解决方案;着重阐述了多工位压力机模具夹持器的使用、工件的导向与定位装置以及废料处理装置设计的关键.