案例教学模式探究

案例教学是一种有效结合理论教学与实践教学的教学方法,是现代高校教育中不可缺少的教学方法.本文介绍了案例教学的特征、案例教学过程中教师的教学方法和注意事项、学生的学习方式、以及实施案例教学的优势,对案例教学的具体实施提出了实效性的方案.     

案例教学模式探究

案例教学是一种有效结合理论教学与实践教学的教学方法,是现代高校教育中不可缺少的教学方法。本文介绍了案例教学的特征、案例教学过程中教师的教学方法和注意事项、学生的学习方式、以及实施案例教学的优势,对案例教学的具体实施提出了实效性的方案。     

独立学院实践教学模式改革初探——以广西八所独立学院为例

论文在理解实践教学模式内涵的基础上，从学分设置、教学安排、教学方式等方面分析了广西独立学院实践教学的现状，并从实践教学体系、大型实践教学、课程内实践教学、特殊实践教学等层面提出了新的教学模式建议。为独立学院实践教学模式改革提供参考。     

浅谈在高职高专教学中教会学生思维

文章通过对高职高专教学中引入思维方法教学的作用和意义进行分析，阐述了一种在教学中引入思维方法教学的一种新的教学理念。     

推进实践教学改革培养高层次应用人才

通过对北华航天工业学院实践教学现状的分析，提出了在理论教学与实践队伍教学的结合、实践教学的队伍建设及制度建设、毕业设计、实习和课外科技活动等方面加强实践教学的具体措施。     

本科模拟电路理论及实验课程教学内容和教学方法的改革与实践

本文主要介绍了模拟电路课程改革的内容和方法：首先是改革陈旧的思想观念、把本科电路教学立足点定位在培养学生成为高素质的应用型人才；在教学过程中坚持基本概念、基本电路和基本应用；精心组织教学内容。灵活调整教学顺序，把理论教学和实践教学有机的结合在一起；采用提问式与启发式相结合，讲授与讨论式相结合的教学方法；利用多媒体CAI课件辅助教学，计算机辅助教学和黑板教学相结合，集中上课和学生白学相结合；实践教学和理论教学并重，实验内容由验证型转向设计型，由单元型转向综合型，实验时间也由分散型转向相对集中型，开设虚拟实验，增加趣味性实验内容等。这些措施的采用都使教学收到良好效果。     

管理学课程的案例教学实践

论文结合作者的实际教学经验，阐述了案例教学的基本原理及案便教学的教师组织工作，并介绍了一个教学实例。     

将素质教育融入数学多媒体课件的尝试——一元多项式的除法的CAI课件教学案例

目前，广大教师都在尝试用计算机辅助教学，尝试制作各种多媒体（CAI）教学课件。这些课件确实为提高教育教学质量起了很好的作用。但其中也有不少课件只追求形式上的华丽而忽视了在教学中所起的作用，或者只是简单地将多媒体当成“黑板”使用。如何恰到好处地发挥多媒体的各种优势，使制作的课件最大限度地提高教育教学的效果？这是很值得我们思考的问题。结合笔者的教学实践体会，就是在使用现代化教学手段的同时，很重要的一点是将我们教学者本身的教学思想、教学目标和教学艺术融入课件之中，在于将素质教育融入课件之中。     

关于高校教学秘书工作的探讨

教学秘书是高校教学管理中的基层人员,是教学工作正常运行的枢纽,其个人素质、知识结构、服务水平对高等教育的改革和发展存在一定影响。论文阐述了高校教学秘书的工作职责,分析了教学秘书队伍存在的问题,进而将"以人文本"的教育管理理念引入到教学秘书队伍建设中,从高校应重视秘书工作和教学秘书应爱岗敬业两方面提出建议,不断加强教学秘书自身素质,以保证教学工作的顺利开展。     

系级教学档案管理模式研究

系级教学档案有自身的特殊性，并且形式多种多样。通过对系级教学档案的类型分析，坚持科学的系级教学档案整理工作的原则，才能高效完成系级教学档案的管理工作。     

Venus transfer design by combining invariant manifolds and low-thrust arcs

The design of interplanetary trajectories based on patched circular restricted three body models is gradually becoming a valuable alternative to the classical patched conic approach. The main advantage offered by such a model is the possibility to exploit the manifold dynamics to move naturally far from or toward a body. Generally, propulsive maneuvers are required to match these structures. Low-thrust arcs offer the possibility to have a significant propellant mass reduction when moving from manifold to manifold. The aim of this paper is to present a methodology to design low-thrust trajectories between two planetary orbits connecting the manifolds of two circular three body systems. The approach is based on a grid search on the main parameters governing the solution to identify those trajectories moving within the manifold images on given Poincarè sections. The value of the Jacoby constant of the target libration point periodic orbit is chosen as stop condition for the thrusting phases. Ballistic arcs follow up to the proper Poincarè section intersection. A grid search for an Earth to Venus transfer is presented as test case.     

基于双蚁群优化的快速轨道转移

研究了Lambert转移的优化问题,并用于航天器的快速轨道机动。以二体模型为基础,在给定的转移时间范围内以燃料最省为目标函数,用蚁群算法(ACA)对Lambert机动问题进行寻优;将第一次寻优用于完成轨道机动所需的速度增量转换成航天器发动机有限推力下的时间序列;考虑地球主要摄动影响,再次用ACA对有限推力工作时段进行边值修正,保证航天器能转移至目标位置范围。仿真结果表明:双蚁群优化方法可有效修正由二体假设导致的Lambert转移的误差,同时由蚁群算法的较强寻优性能保证了Lambert机动过程的燃料最省。     

基于GNSS的通信星座系统的时间同步研究

为近地通信卫星星座系统提出一个将星座各星上时钟同步到地面系统时钟的新技术方案,以GNSS导航系统时钟作为高精度、高稳定的时间基准,利用地面站和星座星上的GNSS接收机基于定位原理测得各自时钟相对于GNSS系统时钟的时差量（秒脉冲相位差）,进一步得出各星时钟相对于地面系统时钟的时差观测量。每个星上时间管理单元利用一个Kalman滤波器估计星地时差模型参数,周期性更新星上时差预报,并据此估计秒脉冲调相时机,以及按照最小调相残差原则估算的调相幅值,并令PPS发生器完成相关调相操作。还设计了上述时统方案在一个典型Walker（24/3/1）星座中的应用研究,并开展了数学仿真和半物理仿真。文章还设计了一个半实物仿真方案,通过数学仿真和半物理仿真,表明该时统方法可将星地秒脉冲相位差自动控制在指定误差范围内,证实其在近地通信卫星星座系统全网时间同步任务中应用的可能性和有效性。     

导弹协同攻击编队自适应滑模控制器设计

Aimed at the need of formation control of missile cooperative engagement, the adaptive sliding mode control theory is introduced to solve the controller design problem of formation based on the leader follower approach. Feedback precise linearization based on differential geometry theory is used to linearize the nonlinear motion model of missile and system model with follower track errors is formulated. In traditional leader follower approach, if the leader moves too fast due to the control saturated, the followers will not be able to track the desired position to keep formation. In order to overcome the disadvantage, an idea of speed control for the leader is introduced to guarantee formation keeping. Finally, an adaptive sliding mode controller is designed to overcome the problem of control input constraints. Theoretical analysis demonstrates that tracking error asymptotically converges to zero. Simulation results show that the leader is able to follow the desired path and the controller can help every missile configure desired formation. The simulation results verify stability and robustness of the formation controllers.     

基于能量约束的翼伞系统分段归航设计与仿真

针对翼伞系统的基本飞行特性和良好的可操纵性,采用分段设计的思想对翼伞系统的归航轨迹进行规划.根据各分段轨迹之间的几何关系,将航迹规划问题转变为对设计参数的寻优问题.实际系统所能提供的能量是有限的.因此,在目标函数中加入控制能量的约束.运用改进的粒子群算法对目标函数进行求解计算,得到整个归航轨迹的设计参数.仿真结果表明:...     

Fostering links between environmental and space exploration: the Earth and Space Foundation

The links between Earth and space exploration occur across a broad spectrum, from the use of satellite technology to support environmental monitoring and habitat protection to the study of extreme environments on Earth to prepare for the exploration of other planets. Taking the view that Earth and space exploration are part of a mutually beneficial continuum is in contrast to the more traditionally segregated view of these areas of activity. In its most polarized manifestation, space exploration is regarded as a waste of money, distracting from solving problems here at home, while environmental research is seen to be introspective, distracting from expansive visions of exploring the frontier of space. The Earth and Space Foundation was established in 1994 to help further mutually beneficial links by funding innovative field projects around the world that work at the broad interface between environmental and space sciences, thus encouraging the two communities to work together to solve the challenges facing society. This paper describes the work of the foundation and the philosophy behind its programmes.     

雷达测量数据转换方法

介绍了利用高精度测量雷达检验其它探测器的数据处理方法.首先根据雷达站点的位置和测量参数计算出目标的坐标,然后用GPS测量探测器的坐标,再计算出探测器到目标的真值参数,最后通过简单的误差分析证明该方法可行.     

再入遥测实时信号处理系统的数据通道设计

根据再入遥测技术的特征,再入遥测系统应具备实时信号处理的能力和切换工作模式的能力。文中用FPGA控制数据通道,选择PCI作为再入遥测系统与计算机的接口,用浮点DSP实现信号的实时处理。经过仿真测试,该方法符合再入遥测系统的要求。     

一种改进的卫星宽带网络拥塞控制算法

以卫星宽带网络为应用背景,从卫星宽带网络的特点出发,设计并实现了一种新 的TCP拥塞控制算法——TCPCA。针对卫星网络高误码率的特点,在接收端采用了Casablan ca分类器区分链路丢包和拥塞丢包。为了克服由大时延带来的重传时间间隔过大的缺点,采 用了批量重传来及时重传丢失的报文段;同时针对大时延致使网络恢复时间延长的缺点,在 发送端采用智能窗口调整策略,避免由于链路错误而减小发送窗口导致的吞吐量下降。利用 仿真软件NS2,通过和传统的TCP拥塞控制机制相比较,TCPCA算法能够提高吞吐量,并且保 证了公平性和友好性。〖JP〗     

Human spaceflight and an asteroid redirect mission: Why?

The planning of human spaceflight programmes is an exercise in careful rationing of a scarce and expensive resource. Current NASA plans are to develop the new capability for human-rated launch into space to replace the Space Transportation System (STS), more commonly known as the Space Shuttle, combined with a heavy lift capability, and followed by an eventual Mars mission. As an intermediate step towards Mars, NASA proposes to venture beyond Low Earth Orbit to cis-lunar space to visit a small asteroid which will be captured and moved to lunar orbit by a separate robotic mission. The rationale for this and how to garner support from the scientific community for such an asteroid mission are discussed. Key points that emerge are that a programme usually has greater legitimacy when it emerges from public debate, mostly via a Presidential Commission, a report by the National Research Council or a Decadal Review of science goals etc. Also, human spaceflight missions need to have support from a wide range of interested communities. Accordingly, an outline scientific case for a human visit to an asteroid is made. Further, it is argued here that the scientific interest in an asteroid mission needs to be included early in the planning stages, so that the appropriate capabilities (here the need for drilling cores and carrying equipment to, and returning samples from, the asteroid) can be included.