基于耦合结构的双向可调无源互调参考源

文章针对无源互调测试领域中亟待解决的无源互调仪器测试校准问题提出了一种基于二极管非线性的人工可调互调参考源设计方法,该种结构使用新型的功率耦合电路网络实现了在双端口双向状态下同时输出可控的无源互调参考信号,两种验证拓扑均可在双路43dBm 载波激励情况下产生小于-110dBm 的可调三阶交调。这种被验证的双路互调参考输出结构在保留反射互调校准功能同时使得传输互调校准也成为可能。针对不同的测试需求还可以通过改变电路结构实现不同的互调调节区间,从而满足不同的互调动态范围的测试需求。在实际互调测试过程中,通过将该人工互调源接入测试回路同时调整偏置电压值,可实现在线的动态互调参考发生及互调测试仪器校准。该电路结构及基于该种结构的校准方法将有助于分析无源互调测试系统的误差水平并进一步指导提高互调仪器的测试准确度。     

区域运输规划模型系统

提出一种区域运输规划模型系统,以求从定量的角度,预测一个区域内的货物运输量,继而确定这些运输量对该区域内存在的多种运输方式的偏好结构,最后仿真这些运量在相应的各种运输网络上的分布情况,同时仿真模型还对运输网线路经过新建或扩建后所形成的新的运量分布进行模拟。根据运量分布情况,就可提出初步的规划建设方案。     

立方体星的技术发展和应用前景

系统论述了立方体星技术发展的三个阶段;从2010-2013年已成功发射的立方体星与纳卫星中挑选了10颗典型卫星,研究分析其技术水平、应用价值和特点优势;并重点论述了立方体纳卫星的应用;最后预测了立方体纳卫星的未来应用前景。     

A strategic flight conflict avoidance approach based on a memetic algorithm

Conflict avoidance （CA） plays a crucial role in guaranteeing the airspace safety. The cur- rent approaches, mostly focusing on a short-term situation which eliminates conflicts via local adjust- ment, cannot provide a global solution. Recently, long-term conflict avoidance approaches, which are proposed to provide solutions via strategically planning traffic flow from a global view, have attracted more attentions. With consideration of the situation in China, there are thousands of flights per day and the air route network is large and complex, which makes the long-term problem to be a large-scale combinatorial optimization problem with complex constraints. To minimize the risk of premature convergence being faced by current approaches and obtain higher quality solutions, in this work, we present an effective strategic framework based on a memetic algorithm （MA）, which can markedly improve search capability via a combination of population-based global search and local improve- ments made by individuals. In addition, a specially designed local search operator and an adaptive local search frequency strategy are proposed to improve the solution quality. Furthermore, a fast genetic algorithm （GA） is presented as the global optimization method. Empirical studies using real traffic data of the Chinese air route network and daily flight plans show that our approach outper- formed the existing approaches including the GA .based approach and the cooperative coevolution based approach as well as some well-known memetic algorithm based approaches.     

Optimization of beamforming and path planning for UAV-assisted wireless relay networks

Recently, unmanned aerial vehicles （UAVs） acting as relay platforms have attracted considerable attention due to the advantages of extending coverage and improving connectivity for long-range communications. Specifically, in the scenario where the access point （AP） is mobile, a UAV needs to find an efficient path to guarantee the connectivity of the relay link. Motivated by this fact, this paper proposes an optimal design for beamforming （BF） and UAV path planning. First of all, we study a dual-hop amplify-and-forward （AF） wireless relay network, in which a UAV is used as relay between a mobile AP and a fixed base station （BS）. In the network, both of the AP and the BS are equipped with multiple antennas, whereas the UAV has a single antenna. Then, we obtain the output signal~to-noise ratio （SNR） of the dual-hop relay network. Based on the criterion of maximizing the output SNR, we develop an optimal design to obtain the solution of the optimal BF weight vector and the UAV heading angle. Next, we derive the closed-form outage probability （OP） expression to investigate the performance of the dual-hop relay network conveniently. Finally, computer simulations show that the proposed approach can obtain nearly optimal flying path and OP performance, indicating the effectiveness of the proposed algorithm. Furthermore, we find that increasing the antenna number at the BS or the maximal heading angle can significantly improve the performance of the considered relay network.     

基于模块度的复杂网络社团结构聚类新算法

针对传统的分裂聚类算法删除连边会影响节点划分的问题,结合K-means算法的思想并加以改进,提出了一种以邻居节点为聚类备选集,所有社团中心节点同时聚类的同步聚类算法。该算法根据节点中心度和最短路变化率确定社团中心节点集,然后以中心节点为社团中心,以邻居节点为聚类备选集合进行聚类,完成社团的划分。将算法应用到Zachary网络中并与GN算法、Top Leader算法进行比较,仿真结果表明该算法对网络有较好的划分。     

无线传感器网络时间同步协议动态切换机制

针对当前无线传感器网络时间同步协议通用性差的问题,提出了基于主动编程思想的时间同步协议动态切换机制,设计了能够动态适配的时间同步协议切换框架,重点讨论了节点间相互通信、时间戳标记、协议切换、本地时间与全局时间的转换等4个关键问题,并且在TinyOS（Tiny Operating System,微操作系统）平台上对新机制进行了仿真验证,比较了新机制同2种主流时间同步协议之间的性能差异.仿真结果表明：新机制能实现时间同步协议的动态配置,提高协同效率,节省切换开销,具有良好的应用前景.     

基于BP网络的机组工作量评估方法研究

为研究机组工作量的评估问题,搭建了模拟飞行实验平台,设定了7种不同负荷的飞行任务。模拟飞行中,对被试的生理指标进行测量,并采集其主观评价值。采用BP网络进行数学建模,将生理指标测量值作为输入、NASA-TLX表法的评价值作为输出,利用输入、输出模式对对网络进行训练,并对该方法进行验证。结果表明,基于BP网络的机组工作量评估方法,较传统方法更为稳定、精确,且大大降低了被试数量。提高训练模式对的数量、简化生理指标的测量过程,并保证测量精度是该方法成功的关键。     

序言CSCD

北斗全球卫星导航系统的建成、应用奠定了我国自主时空信息服务基础,随之我国进入综合PNT体系发展建设新阶段。综合PNT体系将以北斗系统为核A通过多类PNT技术手段协同与融合应用,实现更为精准、泛在和智能的PNT服务能力。通导一体化作为综合PNT核心手段之一,得益于通信极其广泛的覆盖性及日益增强的信息传输能力,依托通信网络对卫星导航系统进行补充、备份和增强,展现出显著的协同优势,因此也成为了领域研究的热点方向。     

《电子商务实务》课程教学改革探索

网络环境下,传统的教学手段和教学模式已不能完全满足电子商务实务课程的教学需要.论文首先指出了桂林航专电子商务实务课程教学中存在的问题,分析了网络环境下该课程教学的特点与优势,并结合笔者的教学实践,探讨了基于网络进行教学改革的方法与思路.