Cooperative Routing for Maximizing Network Performance of Wireless Networks

To greatly increase spectral efficiency and improve network performance in wireless networks,a novel cooperative routing algorithm,namely maximum throughput cooperative routing(MTCR) algorithm,is proposed.According to cooperative link model,throughput analysis is presented to evaluate performance improvement in the process of exploiting cooperative commu-nication from physical layer to higher layer.Taking the throughput improvement as performance metric,a cooperative relay se-lection scheme is developed.Finally,based on the route constructed by adaptive forwarding cluster routing(AFCR) algorithm,each node on the route selects the optimum cooperative node from all the potential cooperative nodes to construct the coopera-tive link with maximum throughput so that cooperative route with maximum network throughput from source to destination can be set up.Simulation results show that compared with the noncooperative routing algorithm and minimum power selection de-code-and-forward(MPSDF) routing algorithm,the proposed algorithm can obviously improve network throughput in the pres-ence of low transmission power,large number of nodes and high spectral efficiency.     

Improved Wavelet-based Spatial Filter of Damage Imaging Method on Composite Structures

Piezoelectric sensor array-based spatial filter technology is a new promising method presented in research area of structural health monitoring (SHM) in the recent years. To apply this method to composite structures and give the actual position of dam-age, this paper proposes a spatial filter-based damage imaging method improved by complex Shannon wavelet transform. The basic principle of spatial filter is analyzed first. Then, this paper proposes a method of using complex Shannon wavelet transform to construct analytic signals of time domain signals of PZT sensors array. The analytic signals are synthesized depending on the principle of the spatial filter to give a damage imaging in the form of angle-time. A method of converting the damage imaging to the form of angle-distance is discussed. Finally, an aircraft composite oil tank is adopted to validate the damage imaging method. The validating results show that this method can recognize angle and distance of damage successfully.     

Long March Launch Vehicles Promote Quick and Sound Development of Satellite Applications

INTRODUCTION Launch vehicles are a precondition and main carrier for space activities for human beings.Their development have directly promoted the technology of satellite applications,manned spaceflight,deep space exploration,and promoted the development of communication,navigation,environmental monitoring,resource exploitation,scientific research and so on.     

网络融合的接入网技术

本文从电信网、广播电视网和因特网三种网络的不同特点入手，说明了三网合一的必要性和可行性，重点探讨了三网合一中关键的接入网技术。     

液压仿真转台位置伺服系统频宽特性的研究

推导了带有加速度、速度、位置反馈的转台位置伺服系统的截止频率、穿越频宽、 - 1 0°相移频宽、 - 90°相移频宽的解析式 ,并就他们与参数之间的关系作了理论分析和讨论     

固定管板式换热器的危险工况分析和管、壳应力在设计中的作用

本文在前文的基础上,阐明危险工况(或称可能出现的危险工况)和真正危险工况之间的区别和联系,仅由操作条件只能列出危险工况而无法得出真正的危险工况,真正的危险工况不仅和操作条件有关,而且和换热器的结构条件和各部件相对尺寸有关。 根据换热器的具体结构条件、各元件相对尺寸和危险工况,管板、管子或壳体应力的最大值都有可能首先超过各自的强(刚)度校核条件。所以,在设计时不论管板、管子或壳体都应由各个危险工况求出其可能出现的最大应力值并校核满足,不能以并非最大的应力值进行校核,更不能因管子或壳体应力(特别是带有膨胀节时)绝对值较低而认为其强度不会成为问题,甚至不予计算。     

无人机神经网络动态逆控制器设计研究

针对无人机动态逆控制器存在的明显缺陷,采用在线神经网络对逆误差进行补偿,设计了神经网络动态逆控制器.构造了一种单隐层神经网络结构,证明了整个闭环系统的稳定性,给出了稳定的在线神经网络权值调整算法.通过仿真验证了该方案的鲁棒性、对故障的适应性以及在作动器纯延时下的响应性能,证明了在线神经网络对动态逆控制器具有明显的改善作用.对于无人机先进飞行控制系统的设计研究具有重要的参考价值.     

某型直升机航空电子系统地面模拟试验仿真平台研究

本文介绍了某型直升机地面模拟试验应用 RT-LAB 集成环境进行地面仿真试验的过程;并阐述了RT-LAB 仿真平台的设计思想和应用前景。     

浅谈理工类专业教师的教书育人工作

在新的历史时期，面对新世纪复杂多变的国际形势和我们面临的艰巨的历史任务，高等教育如何全面实现培养高素质人才的崇高目标，这是关系到建设有中国特色社会主义事业的命运和前途的历史性课题，教师作为人类灵魂的工程师，不失时机地寻找合适的途径做好教书育人工作，这是对教师的基本要求，也是教师的职业道德和责任。     

Article

This is a slightly edited version of the Executive Summary of a joint report on cooperation in space science produced by the Space Studies Board of the USA National Research Council and the European Space Science Committee of the European Science Foundation. Using analysis of 13 case-study missions it reviews 30 years of joint missions and makes 14 recommendations based on its findings. These include the importance of setting a scientific rationale for each mission and of ensuring that objectives are shared by engineers and others involved in it, the need for independent periodic assessments and that all agreements should specify the scope, expectations and obligations of the respective agencies and relevant partners.The USA and Europe have been cooperating in space science for more than three decades. This history of cooperation has survived significant geopolitical, economic and technological changes, such as the end of the Cold War, the pressure of budget reductions and the increasing focus on economic competition and the global marketplace. Both Europe and the USA have learned from one another and acquired a knowledge base as well as an infrastructure to implement joint missions and research activities. More importantly, the decades of cooperative space research efforts between the USA and Europe have built a community of scientists whose joint scientific exchanges have established a heritage of cooperation on both sides of the Atlantic.The scientific fruits of this heritage are plainly evident in achievements such as a signature for supermassive black holes provided by the Hubble Space Telescope (HST); the first views of the solar atmosphere and corona illuminated by the Solar and Heliospheric Observatory (SOHO); the sharing of expensive research facilities on the International Microgravity Laboratory (IML); and the impressive data on ocean altimetry from the Ocean Topography Experiment (TOPEX-POSEIDON) mission, which is significantly improving our understanding of global ocean circulation.There were no guideposts for the emergence of space science cooperation between Europe and the USA. In the process of introducing new procedures and improvements to facilitate cooperation, missteps occurred, and there were political, economic and scientific losses. This report takes stock of US–European history in cooperative space endeavors, the lessons it has demonstrated and the opportunities it suggests to enhance and improve future US–European cooperative efforts in the sciences conducted in space.