基于ITS模型的短波宽带移动信道建模与仿真

短波宽带移动信道模型是远程机动平台移动通信系统性能分析评估的基础,现有短波宽带信道模型不能有效表征机动平台移动信道快时变多普勒效应,难以适应机动平台短波移动通信需要。鉴于此,在分析机动平台行为模式与信道时变多普勒效应的映射关系基础上,推导出了机动平台移动信道冲激响应表达式,基于ITS(international telecommunication society)模型提出了一种适用于固定与机动不同场景、不同传播模式、宽窄带融合的短波通信信道模型。利用信道冲激响应与信道散射函数从时域色散、频域色散两个维度对本文信道模型的有效性进行了验证。结果表明,该信道模型能够基于机动平台运动轨迹实现时变多普勒效应传播复现与信道模拟;也能在运动轨迹未知情况下,基于飞行器种类、机动频率等先验信息,实现具有各态历经性的机动平台短波宽带信道仿真,对机动平台短波移动通信系统效能评估有重要意义。     

面向自主车辆的局部路径规划仿真系统

地面自主车辆研究是当今一个研究热点。由于地面自主车辆运行在户外复杂环境中，因此对仿真系统的研究非常重要。该文介绍了面向室外非结构环境下的自主车辆局部路径规划虚实混合仿真系统，该系统由基于真实环境的二维仿真、算法跟踪调试系统，及用于算法研究的三维虚拟仿真系统组成，采用VC＋＋6.0实现。通过将真实系统实际运行数据与仿真环境结合，为自主车辆的研究与开发提供更好、更真实的仿真环境，并在自主车辆的研究与系统联调中发挥了良好的作用。     

国内外无人地面武器机动平台发展现状及趋势

无人地面机动平台作为20世纪机械、电子、信息、控制等技术发展的集中体现和学科交叉的典型代表,无人地面武器机动平台是无人地面机动平台的一种,他能够进行战场侦察、监视、直接作战,在反恐怖、反袭击、反劫持等方面有很大意义。文章对国内外无人地面武器平台发展现状加以介绍,并对未来的发展趋势做出了大胆的预测。     

轨道机动航天器SINS/GPS自主组合导航算法

为了实现空间机动目标的自主导航,提出了一种基于地心惯性坐标系的轨道机动航天器SINS/GPS自主组合导航算法.首先分析了轨道机动航天器的特点,选取地心惯性坐标系作为导航坐标系.然后建立了导航滤波器的状态方程以及量测方程,其中考虑了SINS系统平台失准角、加速度计误差、陀螺仪误差和加速度计的安装位置和航天器质心之间偏差的影响.最后进行了相关的数学仿真验证,仿真结果表明,该算法可以较准确地给出位置和速度导航信息.     

变结构陆空机器人自主跨域越障技术研究

陆空机器人因其灵活的机动能力而备受关注,为了更好地发挥陆空机器人的跨域越障特性,以变结构陆空机器人为平台,对深度图像进行二值化处理以提取前方障碍物的边缘轮廓,采用最小矩形匹配法对障碍物进行建模,获取障碍物的距离及高度信息.根据障碍物距离和高度的检测结果及平台地面移动越障极限,提出了一种自主跨域越障策略.试验结果表明,机器人可以准确检测判断出行驶前方障碍物的距离及高度信息并可以顺利自主跨域越障,到达目标点,提出的障碍物检测方法及自主跨域越障策略是有效的.      

油气场站自动化巡检机器人系统设计

油气场站存储的物质由于具有可燃性,需要高频率的进行巡检。针对油气场站分布较广,占用面积较大,人工巡检费时费力,需要携带各种传感器进行采集与分析数据的问题,设计了一套油气场站自动化巡检机器人系统。该巡检系统包括自主移动平台、底层控制及传感器、自主导航算法、传感器检测算法、数据处理与预警平台。通过设计的被动式底盘和自主导航算法,该系统能够在油气场站的非结构化路面上进行快速巡检;通过设计的传感器检测及处理预警平台,该系统能够对油气场站的甲烷等易燃气体进行自主分析并数据回传,使得检测流程更加简洁高效。经实验测试,本油气场站全自动化巡检机器人系统能够完成灵活的越过各种障碍物,在危险环境下进行巡检,自主建立环境地图并导航,环境异常检测并回传数据,数据分析并报警等复杂任务,能够广泛的运用在油气场站的自动化巡检任务中。     

基于地图建立的无人地面车路径规划

 提出一种同时完成地图建立与路径规划的算法。该算法为两层控制结构,其上层实现子目标点的生成,下层完成局部路径规划及运动控制。根据系统实时性的要求,以N个系统周期为触发条件执行子目标点生成程序。其中无人地面车通过传感器不断获取环境信息并进行处理,完成网格占据方式的地图建立与实时更新;将地图建立的结果作为数据输入,利用A*路径规划算法生成子目标点。根据子目标点生成结果,在每个系统周期内,通过基于模糊控制的底层快速算法完成无人地面车到子目标点的运动控制。以Pioneer 3-AT型无人地面车为试验平台在未知的复杂环境中对该算法进行验证,取得了良好的地图建立和路径规划效果,证明了该算法具有良好的实时性和准确性。     

轨道交通巡检移动平台研究与设计

为适应轨道交通系统设备多、复杂多变的环境,提出了一种适用于轨道交通领域的巡检移动平台.它具有两足,能够两足交替抬离地面实现类似步行的步态.进行了巡检移动平台的结构设计、运动学分析以及稳定性分析,为平台设计提供了理论支撑.在多体动力学仿真软件中建立该两足巡检移动平台的虚拟样机模型,进行了步行仿真.在此基础上,制作了1台样机,实现了期望的移动.该巡检移动平台结构设计灵巧,控制简单,具有一定的实用价值.     

空基多平台多传感器机动目标自适应跟踪

在空战中，需要基于空中移动平台对机动目标进行自适应跟踪．由于机动目标“当前”统计模型符合实际目标的动力特征，所以文中基于该模型，针对空基多平台多传感器环境，推导了机动目标跟踪的状态方程和测量方程，并给出了机动目标自适应跟踪算法．Monte—Carlo仿真表明，该方法能有效地估计出机动目标的运动状态．     

MABEMS:一个基于移动Agent的电子市场空间

随着Internet的广泛普及，电子商务应用系统，尤其是基于Internet的电子市场系统日益受到重视，然而面对Internet这种新的网络环境，传统的客户／服务器技术并不适宜构造此类系统，近年来，移动Agent技术被认为是一种易于、实现和维护Internet环境下分布式系统的新兴技术，提出了一个基于移动Agent的电子市场空间模型，并在本实验室的移动Agent系统－Mogent平台上实现了其原型系统，该市场空间采用开放的、非集中的系统结构，具有较高的灵活性和可靠性，自动化程度较高，最后介绍利用可扩展标记语言XML和知识查询与操纵语言KQML，实现市场空间的信息描述和Agnet之间的交互。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the