Robust Adaptive Control Design for Rotorcraft Unmanned Aerial Vehicles Based on Sliding Mode Approach

This paper presents a nonlinear robust control design method for a generic rotorcraft unmanned aerial vehicle（RUAV）. The control objective is to let the RUAV track some pre-defined time-varying position and headingtrajectories. The proposed controller employs feedback linearization process to realize the dynamic decoupling controland applies adaptive sliding mode control to compensate for the parametric uncertainties and external disturbances.The global asymptotical stability is proved via stability analysis. Compared with the cascaded controller, the proposedcontroller demonstrates a superior tracking performance and robustness through numerical simulation in the presenceof parametric uncertainties and unknown disturbances.     

Noisy chaotic neural network for resource allocation in high-speed train OFDMA system

High-speed train communication system is a typical high-mobility wireless communication network. Resource allocation problem has a great impact on the system performance. However, conventional resource allocation approaches in cellular network cannot be directly applied to this kind of special communication environment. A multidomain resource allocation strategy was proposed in the orthogonal frequency-division multiple access （OFDMA） of high-speed. By analyzing the effect of Doppler shift, sub-channels, antennas, time slots and power were jointly consid- ered to maximize the energy efficiency under the constraint of total transmission power. For the purpose of reducing the computational complexity, noisy chaotic neural network algorithm was used to solve the above optimization problem. Simulation results showed that the proposed resource allocation method had a better performance than the traditional strategy.     

正交频分复用光通信实验系统设计与实现

设计了基于直接检测的正交频分复用(DD-OFDM)光通信实验系统,能够反映出OFDM光通信系统的主要特征,且离实用距离较近。DD-OFDM光通信系统包括OFDM信号的构造、OFDM信号的析构以及光纤传输3个部分功能,在实验中分别由任意信号发送器、数字系列分析仪以及自行搭建的光纤传输链路实现,实现了10 Gbit/s二进制序列经16QAM映射、64载波传输、在25 km单模光纤中的可靠传输。给出星座图和不同接收光功率条件下系统的误码性能的实验结果。为OFDM高速光通信的教学与科研提供实验平台和实验样板。     

基于两种算法的天然气管网运行优化技术

为了保证管网能够安全、高效、经济地运行,建立了基于两种优选算法的天然气管网优化模型。在对比了现有各种优化算法的基础上,选用改进线性逼近法和序列二次规划法作为天然气管网运行优化研究的算法,分析了两种算法的原理,并以运行能耗最低为目标进行优化计算研究。为了既能满足生产需求,降低算法本身对目标函数和约束条件的依赖性,又能够保证计算效率和稳定性,优选出序列二次规划法,从生产实际出发建立一套通用性较强的天然气管网稳态运行优化模型,也为软件开发提供前期的数据分析。     

层次分析法在《绩效管理》课程的教学思路及案例解析

《绩效管理》课程是人力资源管理专业的专业核心课程之一,该课程的重点内容是利用定性和定量方法对组织内的人员进行绩效考核与评价。由于此部分内容涉及较多的统计学的综合评价分析原理及步骤,在教学过程中师生普遍反映有一定的难度。究其原因,主要在于学生未能将综合评价分析方法与绩效考核流程相结合。文章归纳总结了综合评价方法在绩效考核课程的运用思路,其中关键点是构建评价指标体系和估算权重,并通过案例展示了层次分析法(AHP)在绩效考核中的教学思路及步骤以便于教学。     

关于“飞翔”的若干追问与思考——作家毕华勇作品解读

毕华勇是陕西著名作家。作品主要反应陕北黄土地上农民命运的演变,风格浑厚朴素,弥漫着厚重浓郁的乡土气息,反应出作者本人深深的乡土情结以及由此引发的重重困惑。在当代农村题材创作中具有独特的代表意义。研究发现,毕华勇之"乡愁"的沉重以及"飞翔"的艰难,原因是当精神依旧眷恋故园的恬静美好时,身体却早已飞向天空,身心的割裂就成为必然,于是作者不得不反思、追问、寻找,伴随精神的一路迷茫,以不同人物命运的起伏悲欢来展现这一特殊历史时期这个阶层的人性演变。     

陌生化理论视野下的毕飞宇短篇小说艺术探析

毕飞宇是当今文坛当之无愧的优秀短篇小说家之一。以陌生化理论审视其叙述视角和语言可以发现,在毕飞宇短篇小说中,无论是充满伤痛的文革叙事还是现代城镇中的成长忧伤,都裹挟着撼人心魄的力量,直接冲击着读者的心灵,从而赋予了读者更多更新的艺术感受。     

略谈《镜花缘》与《笔生花》中女子家庭生活的描写

《镜花缘》和《笔生花》的作者均充分肯定女子的才能,才女们在外都高中科举,并参与平定叛乱。两部作品对女子的家庭生活都有描写,如才女们的家庭教育、婚姻状态、日常生活等方面,并显示出各自的描写特点。     

Drama to Enhance the Speaking Skills of EFL/ESL Learners

The paper starts with introducing the definition of drama. Then, many drama techniques are introduced. Next, Advantages of using drama techniques are discussed. Nonetheless, some problems in using drama in ESL/EFL are pointed out. The paper concludes that drama offers a useful educational tool to support communicative language teaching for EFL/ESL learners.