Optimum Relay Location in Cooperative Communication Networks with Single AF Relay

In recent years cooperative diversity has been widely used in wireless networks. In particular, cooperative communication with a single relay is a simple, practical technology for wireless sensor networks. In this paper, we analyze several simple network topologies. Under the condition of equal power allocating, the optimum relay location of each network topology are respectively made sure by using symbol error rate (SER) formula. And these types of topologies are compared, the analysis results show that, linear network topology has the best system performance, the system performance of isosceles triangle topology is better than that of equilateral triangle topology.

Binding of Mono, Bi and Tridomain Proteins to Zwitterionic and Anionic Vesicles： Asymmetric Location of Anionic Phospholipids in Mixed Zwitterionic/Anionic Vesicles and Cooperative Binding

Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorption to zwitterionic PC and anionic mixed PC/PG SUVs. Protein adsorption is investigated in SUVs along with changes of fluorescence emission spectra. Partition coefficients and cooperativity parameters are calculated. At pl binding obtains maximum while at lower or higher pHs binding decreases. In Gouy-Chapman formalism activity coefficient goes with square charge, which deviations indicate asymmetric location of anionic phospholipid in the inner leaflet, in mixed SUVs for lysozyme- and myoglobin-PC/PG systems, in agreement with experiments and molecular dynamics simulations. Vesicles bind myoglobin anti-cooperatively while lysozyme-BSA cooperativitivey. A model is proposed for both, which composes two protein sub-layers with different structures and properties. Hill coefficient reflects subunit cooperativity of bi and tridomain proteins.

A Method to Obtain the Moving Speed of Uncooperative Target Based on Only Two Measurements

The existing research results show that a fixed single station must conduct three consecutive frequency shift measurements and obtain the target’s moving speed by constructing two frequency difference equations. This article proposes a new method that requires only two consecutive measurements. While using the azimuth measurement to obtain the angular difference between two radial distances, it also conducts two consecutive Doppler frequency shift measurements at the same target azimuth. On the basis of this measurement, a frequency difference equation is first constructed and solved jointly with the Doppler frequency shift equation. By eliminating the velocity variable and using the measured angular difference to obtain the target’s lead angle, the target’s velocity can be solved by using the Doppler frequency shift equation again. The new method avoids the condition that the target must move equidistantly, which not only provides an achievable method for engineering applications but also lays a good foundation for further exploring the use of steady-state signals to achieve passive positioning.

Multi-UAV Network Assisted Intelligent Edge Computing:Challenges and Opportunities

Introducing multi-UAV network with flexible deployment into mobile edge computing(MEC)can effectively improve the quality of service of Internet-of-Things services,reduce the coverage cost and resource waste rate of edge nodes,and also bring some challenges.This paper first introduces the current situation and pain points of mobile edge computing,then analyzes the significance and value of using multi-UAV network to assist mobile edge computing,and summarizes its key technologies and typical applications.In the end,some open research problems and technology prospects of multi-UAV network assisted intelligent edge computing are put forward,which provide new ideas for the future development of this field.

UAVs cooperative task assignment and trajectory optimization with safety and time constraints

This paper proposes new methods and strategies for Multi-UAVs cooperative attacks with safety and time constraints in a complex environment.Delaunay triangle is designed to construct a map of the complex flight environment for aerial vehicles.Delaunay-Map,Safe Flight Corridor(SFC),and Relative Safe Flight Corridor(RSFC)are applied to ensure each UAV flight trajectory's safety.By using such techniques,it is possible to avoid the collision with obstacles and collision between UAVs.Bezier-curve is further developed to ensure that multi-UAVs can simultaneously reach the target at the specified time,and the trajectory is within the flight corridor.The trajectory tracking controller is also designed based on model predictive control to track the planned trajectory accurately.The simulation and experiment results are presented to verifying developed strategies of Multi-UAV cooperative attacks.

Research on Estimation of Time Delay Difference in Passive Locating for Impulse Signal

Analyzed the relation between time delay difference and time delay estimation errors, based on the principles of three-point locating, a reformed threshold method for time delay difference estimation of impulse signals, called as amendment estimation for short, is developed by introducing channel equalization technique to its conventional version, named as direct estimation in this paper, to improve the estimation stability. After inherent relationship between time delay and phase shift of signals is analyzed, an integer period error compensation method utilized the diversities of both contribution share and contribution mode of concerned estimates is proposed under the condition of high precision phase lag estimation. Finally, a cooperative multi-threshold estimation method composed of amendment and direct estimations to process impulse signals with three thresholds is established. In sea trials data tests of passive locating, this method improves the estimation precision of time delay difference efficiently. The experiments verify the theoretical predictions.

合作环境下共享枢纽选址决策与优化

针对多承运商联合选址及枢纽共享决策与优化问题,从横向合作角度出发,以总成本最小为目标,分别构建共享及非共享情形下,考虑多分配模式且有容量限制的枢纽选址模型,并分析企业共享决策对运作成本的影响。结果表明:共享枢纽网络在一定条件下比不共享枢纽网络更能节约成本,共享的额外补充成本直接影响着承运商的共享决策及枢纽选址的优化效果;随机式分布对额外补充成本因子相对不敏感,合理规划初始枢纽选址并适当地调整补充成本因子,有助于枢纽网络实现成本控制目标。该研究可对物流网络枢纽选址及合作决策的制定提供参考。

非合作线谱声源分布式定位方法

非合作目标定位是水声定位领域的研究热点。为充分挖掘并利用各类可观测参数,提高非合作目标定位能力,提出一种基于目标频率变化信息的非合作目标定位方法。该方法针对匀速直线运动目标的定位问题,首先根据多普勒频移原理,建立观测频率与目标辐射频率、目标运动速度、位置之间的函数映射关系,利用最小均方准则建立目标函数,通过优化算法估计分布式定位系统中各个测量单元与目标运动轨迹的致近点距离,最后综合各观测节点的测距结果,构建几何定位模型,求得目标运动轨迹的解析解。通过仿真分析,证明了该方法的有效性,并指出了该方法需要目标通过与各测量单元的致近点才能获得较好的距离估计能力。文中分析了不同频率估计精度对定位精度的影响,结果表明,提出的定位方法对测频精度具有一定的容限,是一种高精度的非合作线谱声源定位方法。

凭什么深化:职业教育产教融合的制度规划、市场匹配与组织结对

职业教育产教融合经过多年的规模化仍表现出制度规划的空泛化、市场合作的盲目化与特定组织合作的松散化困境。解决这一问题,不能仅仅从区域平衡、社会责任或市场利益等单一层面出发,而需要系统地理性分析融合难题的本质,多层面探讨和分析区位布局的原则及其实际应用。为实现高质量的产教融合发展,需要从简单的直觉式布局转向基于逻辑的理性规划。具体措施包括:完善产教系统的整体规划,提高区位合作制度的精确度和准确度,降低合作成本;明确市场匹配的指导原则,优化匹配效率和信息成本;考虑特定区位因素,采取因地制宜的策略,分类指导各地区和各类区位的产教融合组织进行深度合作。

考虑患者转运的跨区域动态协同应急物流选址-分配优化研究

针对突发公共卫生事件下多个受灾地区之间跨区域应急资源配置的现实需求,研究考虑患者转运的跨区域动态协同应急物流选址−分配优化问题,构建跨区域的患者转运与应急资源协同配置两阶段优化决策模型。模型第1阶段优化确定患者动态变化与相应医院数量及其选址,第2阶段优化确定应急物资配送中心选址与应急物资分配。该优化模型同时考虑应急物流总成本(包括设施固定成本与运营成本)与转运时间2个优化目标,且考虑多周期动态变化的实际需求。针对上述优化模型特征,设计嵌入模型预测控制(MPC)方法的改进遗传算法。该算法将每个决策周期分为3个环节:1)疾病扩散预测环节,即每个周期开始时对疾病发展趋势进行预测;2)应急决策规划及实施环节,根据规划窗口的预测数据制定并实施应急选址−分配方案;3)数据更新与动态调整环节,即每个执行周期结束时,根据实际执行数据制定下一个周期决策。3个环节交互进行,相互迭代直到完成整个规划时期。最后,以贵州省跨区域的应急资源协同配置优化为例,验证所提优化模型及其求解算法的有效性。研究发现:与各区域独自应急相比,跨区域动态协同应急方案在转运时间没有明显增加的情况下,能有效降低应急成本,能够高效率地利用应急设施为感染患者提供救治。研究成果为突发公共卫生事件中多区域之间的协同应急资源配置优化提供决策支持。

Elite Dung Beetle Optimization Algorithm for Multi-UAV Cooperative Search in Mountainous Environments

This paper aims to address the problem of multi-UAV cooperative search for multiple targets in a mountainous environment,considering the constraints of UAV dynamics and prior environmental information.Firstly,using the target probability distribution map,two strategies of information fusion and information diffusion are employed to solve the problem of environmental information inconsistency caused by different UAVs searching different areas,thereby improving the coordination of UAV groups.Secondly,the task region is decomposed into several high-value sub-regions by using data clustering method.Based on this,a hierarchical search strategy is proposed,which allows precise or rough search in different probability areas by adjusting the altitude of the aircraft,thereby improving the search efficiency.Third,the Elite Dung Beetle Optimization Algorithm(EDBOA)is proposed based on bionics by accurately simulating the social behavior of dung beetles to plan paths that satisfy the UAV dynamics constraints and adapt to the mountainous terrain,where the mountain is considered as an obstacle to be avoided.Finally,the objective function for path optimization is formulated by considering factors such as coverage within the task region,smoothness of the search path,and path length.The effectiveness and superiority of the proposed schemes are verified by the simulation.

基于N-EKF的非合作低轨目标双星无源定位跟踪算法

针对两颗天基光学卫星对低轨非合作目标进行无源定位跟踪的问题,提出了一种基于Newton迭代与扩展卡尔曼滤波(Newton iteration and extended Kalman filter,N-EKF)的定位跟踪算法。首先,将基于角度测量信息的双星观测模型转化为双直线公垂线中点问题,并进一步转化为非线性方程问题,使用Newton迭代算法得到非合作目标的初始定位信息。然后,采用扩展卡尔曼滤波(extended Kalman filter,EKF)方法,在初始定位信息基础上,结合近地轨道动力学模型,实现对非合作在轨目标的精确跟踪滤波。最后,通过仿真验证了所提方法的可行性及优势。

一种基于多舰协同侦察的优化布站方法

相较于传统岸基超视距雷达、侦察飞机和侦察卫星等侦察定位手段,舰载超视距侦察定位系统具有布站灵活、成本低廉以及预警范围广等优点,但其相对于目标的位置会影响多舰对目标定位的精度。针对上述问题,文章提出了一种基于改进的粒子群优化算法的多舰布站优化方法,以测向交叉定位的几何精度因子作为适应度函数,进而循环迭代出最优的布站方法。在多舰协同侦察场景下,通过比较该算法与标准粒子群优化算法的优化结果,仿真分析2种方法在本场景下的寻优效果和迭代次数,该方法具有收敛速度更快、优化结果更好的特点。

现代物流发展与港口区位合作博弈分析

现代综合物流服务逐渐取代传统的运输业是当前社会向后工业时代、信息社会时代转变的重要特征之一。作为物流系统最重要的节点,现代港口区位发展的关键是通过与物流系统的其他节点之间有效的合作,不断提高整个物流系统的综合物流能力。文章分析了现代物流迅速发展背景下港口区位特征与功能以及港口与物流系统内各节点之间的相互作用和相互依存关系,并运用博弈论理论,对港口区位合作机制进行探讨。

基于距离测量的多无人机协同目标定位方法

提出了一种利用多无人机与目标之间的距离以及无人机站址坐标估算目标位置的协同定位算法。通过一阶Taylor展开,把非线性距离测量方程转化为量测距离信息加上无人机的站址误差以及测距传感器的测距误差信息方程,进而对定位方程求解,得到目标的位置。最后利用在线枚举法寻求最小GDOP值所映射的最优编队队形以提高定位精度。计算机仿真结果验证了该算法的有效性和适应性。

基于非合作雷达辐射源的无源雷达技术综述

对基于非合作雷达辐射源的无源雷达技术进行了综述,介绍了该领域内的研究历史与现状。然后对非合作式双基地雷达系统基本原理进行了分析与研究,主要内容包括基本几何关系、信号能量关系、接收站的组成以及参数测量与目标定位方法。最后,对辐射源的信号分析与优化选择、系统同步、直达波参考信号的恢复、微弱目标信号的检测与参数估计以及跟踪、融合与目标识别等系统关键技术进行了分析与评述。

两弹协同定位的可行性研究

对两枚导弹协同定位的可行性进行了研究,推导出了其能有效定位的条件。并对正常工作下两枚导弹的信息共享、协同作战情况进行了仿真研究。结果表明,当两导弹均距离目标较远,或两导弹一远一近的情况下,通过信息融合,协同定位,可以有效提高单个导弹的定位精度,同时定位精度也受导弹本身站址误差的影响。

双机协同定位误差分析的研究

测向交叉定位技术是协同定位常用方法,针对双机协同测向交叉定位算法及其定位精度进行理论研究和仿真分析。首先给出了交叉定位造成的模糊区的计算方法,并进行仿真;而后重点对测向定位精度进行分析,给出定位算法和误差计算公式,并针对不同载机间距和间距误差、测角误差下的目标GDOP的分布进行了仿真分析。仿真结果表明,定位误差随着间距误差、测角误差的增大而增大,随着双机间距的增大先减小而后增大。

基于Chan氏算法和Taylor级数展开法的协同定位方法

该文分析讨论了Chan和泰勒两种TDOA定位算法的优缺点,并在此基础上提出了基于 Chan氏算法(1994)和Taylor级数展开法(1976)的协同定位方法。通过在不同信道环境下对协同定位 方法进行仿真,表明该方法在信道环境恶劣时能够有效地提高定位精度。

非合作双基地雷达参数测量与定位方法研究

介绍了非合作双基地雷达的基本几何关系,讨论了非合作双基地雷达中四个重要参数(基线距离、双基地距离差、发射站目标方位角、接收站目标方位角)的测量方法,利用这四个参数可构成四种定位算法。推导了这四种算法的定位误差公式。仿真结果表明,各算法的定位精度与双基地雷达系统的几何结构有关,且有着不同的空间分布规律。实际系统定位方案的选择应根据所能测出的参数来定,同时应注意各算法的适用区域。