基于数字信息素的无人机集群搜索控制方法

研究了无人机集群搜索问题的由来、概念、特点,反应行为机制的重要性以及信息素的应用价值。模拟两种基本的生物信息素,设计了一种基于数字信息素的无人机集群搜索控制方法。从全局决策和单机决策的角度,建立了基于数字信息素的无人机集群搜索分布式决策方法。抽象出所建立的数字信息素模型的主要特征,研究分析了具备此类特征的集群搜索系统的稳定性,并确定了集群边界。仿真结果表明,该方法能够形成稳定的数字信息素闭环,能够和所设计的飞行决策方法结合,使多机呈现出鲜明的集群行为特征,实现无人机集群搜索控制;仿真同时表明,该方法驱动的无人机集群搜索的效率显著优于常规编队模式,这也从侧面证明了无人机集群的搜索能力远高于无人机编队。

GaN基紫外数字像素光电传感器设计与实现

介绍了一种为了获得高速高性能的GaN基紫外数字像素光电传感器的设计和实现。该传感器每个像素单元面积为50μm×50μm,包含一个UV光电探测器,一个1位比较器和一个3 T的存储单元,能同时完成对所有像素的A/D转换。像素内比较器电路中引入了一个自动复位电路用以实现数字相关双采样功能,并可以增加峰值信噪比以及动态范围。电路采用CSMC DPTM 0.5μm CMOS工艺流片实现,初步的功能实验结果验证这一数字传感器能正常工作。

基于数字信息素的无人机集群频谱监视控制算法

频谱监视对电磁环境的频谱态势掌握至关重要.特别地,用无人机集群作为执行对象,可以提高监视效率,节省大量人力成本.本文针对频谱监视任务,设计了用于评估监视效果的评价函数,提出了一种基于人工势场的数字信息素无人机集群安全控制算法.该算法使用数字信息素矩阵来模拟电磁空间的搜索状态,并通过在集群内的个体之间建立信息素势场以实现自适应的无人机集群分布式航迹规划.周期性的采样和插值解决了未知域的优先级矩阵更新问题,引导无人机优先监视频谱热点区域.不同于已有的基于飞行概率的决策算法,本文算法充分利用了数字信息素所映射的环境信息,可以避免无人机陷入局部状态的重复搜索,适用于动态频谱环境.仿真实验表明本文的决策算法在静态和动态频谱监视场景下均能使评价函数快速收敛,达到较好的监视效果.

基于数字信息素的分布式决策技术

为满足未来电磁作战需求,对无人集群网络、信息交互和自主决策技术进行研究,力求提高无人集群执行任务水平。首先,提出大规模电磁作战集群网络体系架构。然后,为兼顾实时共享与鲁棒决策需求,提出一种基于数字信息素的交互机制。基于该机制,集群能够快速分配资源并开展多项任务。在作战过程中,通过闭环、自适应的在线评估,电磁作战集群能够根据战场态势,智能、实时地改变资源配比,优化作战效能。

教育数字化背景下幼儿园教育面临的机遇与挑战

教育数字化正在改变幼儿教育,给幼儿园带来机遇与挑战。教育数字化可以促进幼儿园教学管理和教育教学水平的提升,助力幼儿园教师专业发展。同时,教育数字化也使幼儿园面临数字技术应用准备不足、数字化应用隐忧、教师职责和师幼关系变化等挑战。教育数字化背景下,幼儿教师需要转变观念,提升自身数字素养和技能,关注幼儿全面发展,幼儿园也应审慎规划和管理人工智能等新技术应用。

带信息素回访机制的多无人机分布式协同目标搜索

为了提高无人机对目标的搜索捕获能力和对不确定度较高的区域的回访能力,进而提高多无人机协同搜索效率,提出了一种带信息素回访机制的多无人机协同目标搜索方法。首先,建立了包含目标存在概率地图、不确定地图和数字信息素地图在内的环境感知地图及其更新机理,使得无人机对任务区域中环境和目标信息的感知更加全面和准确,为无人机在线自主地进行搜索决策奠定基础。其次,考虑到任务子区域的可控回访需求,借鉴信息素"释放-传播-挥发"的特性,设计了基于信息素的网格回访机制,来引导无人机对目标存在可能性较大的区域或者不确定度较高的区域进行回访搜索。最后,设计了基于环境感知地图的协同搜索决策性能指标,在分布式滚动时域优化框架下,建立了多无人机协同搜索决策方法。使用蒙特卡罗方法验证了无人机数量、传感器探测靶面半径、传感器性能对搜索效率的影响。对比仿真表明,信息素回访机制能够保证较强的遍历能力和回访能力,使得无人机能够尽早搜索到更多的目标,尽快地降低整个搜索区域的不确定度。

用于数字图像传感器的脉冲宽度调制读出方法研究

为提高数字像素图像传感器的动态范围,提出了一种具有自适应参考电压的脉冲宽度调制读出方法。该方法将像素阵列分成包含相同数目像素的像素块,通过参考电压产生模块使每个像素块的参考电压和像素块内光照强度相关,理论上这种结构能够将数字像素图像传感器的动态范围从48 d B提升至96 d B,实际仿真结果为88.16 d B。分析了像素分块内主要的噪声来源和参考电压产生模块的采样电容引入的偏差。采用65 nm CMOS工艺实现了4×4的像素块电路,在高光强和弱光强条件下分别将电路输出同理论计算值相比较,并分析了产生误差的原因。

像素级模数转换器研究进展

像素级模数转换器因其独特的集成位置而具有高帧频、大动态范围、低功耗及低噪声等优点,广泛应用于红外、可见光及太赫兹成像等领域。文章介绍了主流像素级模数转换器结构的原理,综述了像素级模数转换器在动态范围、功耗、面积及噪声等性能参数的研究进展,最后分别比较和总结了各改进方向的几种关键技术并做出展望。

复杂环境下异构无人机集群协同目标搜索方法

为实现无人机集群高效且精准的多目标搜索,考虑集群成员中探测范围广的高空无人机和机动能力较强的低空无人机,提出了一种新颖的异构无人机集群协同目标搜索方法,根据不同无人机的特性快速实现区域搜索以及多目标的精准搜索。高空无人机采用基于数字信息素的区域搜索算法确定目标存在区域,在较短时间内实现区域覆盖。低空无人机在其指引下前往目标区域,并根据目标信号强度采用改进狼群算法实现对目标的精准搜索。对于传统狼群算法信息共享不足、步长固定和易陷入局部最优的问题,采用粒子群算法、自适应参数调整和差分进化方法进行改进,提高了算法的全局寻优能力和收敛速度。仿真实验证明了所提出的模型与方法在复杂环境下目标搜索任务中的有效性和优越性。

面向动态目标搜索与打击的空地协同自主任务分配方法

面向复杂城市环境中的运动目标搜索与打击任务,单域无人平台受视野范围和运动能力等限制,易出现目标遗漏和任务完成率低的问题。针对这些问题,提出一种面向动态目标搜索与打击的空地协同自主任务分配方法,通过结合无人机视野范围广以及无人车机动性强的特点,提升空地无人系统的任务执行效率和区域覆盖率。一方面,针对未知运动目标,提出一种基于数字信息素的目标搜索模型,以平台协同收益和区域覆盖率为优化指标,保证在尽可能短的时间周期内发现区域中的所有目标。另一方面,面向动态到达的打击任务,构建基于可行路径规划的任务分配模型,以平台能耗和任务完成时间为目标函数,在保证任务完成率的同时,提高空地协同系统的资源利用率。与现有方法相比,所提方法能够在最短的时间内发现所有目标,区域覆盖率达到55%以上,且资源利用率为84.4%。实验结果表明,所提方法具备较好的目标搜索和任务执行能力。

基于MTPM和DPM的多无人机协同广域目标搜索滚动时域决策

传统的协同搜索决策方法在目标引导和机间协同方面存在不足.研究建立了基于分布概率预测的目标概率图(Target probability map,TPM)初始化方法和基于贝叶斯准则的目标概率图动态更新方法,形成了修正目标概率图(Modified TPM,MTPM)及其运算机理.考虑对任务子区域进行可控回访,定义了数字信息素图(Digital pheromone map,DPM),建立了数字信息素图使用方法及更新机理.设计了基于MTPM和DPM的寻优指标,建立了基于滚动时域控制的协同搜索决策方法(MTPM-DPM-RHC method,MDR).仿真表明:1)MTPM能有效降低对目标的虚警率和漏检率;2)DPM能有效实现对任务区域可控回访;3)MDR方法的遍历能力、重访能力和目标搜索效率均优于已有方法.

通信受限下多无人机协同运动目标搜索

针对搜索问题中的目标通信限制和运动特性,采用连通矩阵建立了无人机通信拓扑结构。基于贝叶斯理论利用多架无人机联合探测信息对目标存在的后验概率进行更新,通过计算目标转移概率密度得到动态时敏目标的预测概率,提高了目标存在概率图的准确性;设计了一种调度信息素,建立了数字信息素图使用方法及更新机理,增强了无人机的协作性。在此基础上设计了合理的UAV协同搜索性能指标函数,最后在分布式模型预测控制框架下对性能指标函数进行优化求解,仿真结果表明两种搜索图能够引导无人机协同搜索,加强了机间合作,提高了搜索效率。

Determining Topographic Shielding from Digital Elevation Models for Cosmogenic Nuclide Analysis:a GIS Approach and Field Validation

Topographic shielding of cosmic radiation flux is a key parameter in using cosmogenic nuclides to determine surface exposure ages or erosion rates. Traditionally, this parameter is measured in the field and uncertainty and/or inconsistency may exist among different investigators. This paper provides an ArcGIS python code to determine topographic shielding factors using digital elevation models （DEMs）. This code can be imported into ArcGIS as a geoprocessing tool with a user-friendly graphical interface. The DEM-derived parameters using this method were validated with field measurements in central Tian Shan. Results indicate that DEM-derived shielding factors are consistent with field-measured values. It provides a valuable tool to save fieldwork efforts and has the potential to provide consistent results for different regions in the world to facilitate the comparison of cosmogenie nuclide results.

紫外DPS中DA控制器的NiosⅡ-IP核设计与实现

详细介绍了GaN基紫外数字像素探测器(DPS)多通道位串行(MCBS)实现方案中共用DAC设备控制器的自定义IP核的设计和功能实现。文中采用基于嵌入式软核NiosⅡ处理器可编程片上系统(SOPC)设计方法,通过对以12位数模转换芯片TLV5639为控制对象的IP核的仿真和测试,验证了设计的正确性。实验结果表明设计符合性能要求,基于SOPC的IP核设计方法具有较强实用性和通用性。

未知区域中四旋翼无人机集群协同搜索与围捕算法

四旋翼无人机集群可以被用来进行区域侦察,以建立对环境与兴趣目标的认知。为四旋翼无人机集群提出一种分布式协同搜索算法和动态目标包围技术,以解决在未探测区域定位和监测目标中所遇到的挑战。为降低所提算法的复杂度,通过栅格划分方法将任务区域划分为2级栅格子区域。考虑到动态目标的随机性,设计一种数字信息素来引导多无人机对任务区域进行2次搜索,并以快速搜索到目标为奖励函数,通过滚动优化决策得到最优解作为无人机的输入。然后,基于一致性协议设计一种多无人机协同跟踪与围捕协议,以获取动态目标的实时信息。数个仿真结果与室外飞行实验验证了所提算法能够使四旋翼无人机对未知区域中动态目标进行有效搜索与动态监视。

Vibration Analysis for the Comfort Assessment of Superyachts

Comfort levels on modern superyachts have recently been the object of specific attention of the most important Classification Societies, which issued new rules and regulations for evaluating noise and vibration maximum levels. These rules are named "Comfort Class Rules" and set the general criteria for noise and vibration measurements in different vessels' areas, as well as the maximum noise and vibration limit values. As far as the vibration assessment is concerned, the Comfort Class Rules follow either the ISO 6954:1984 standard or the ISO 6954:2000. After an introduction to these relevant standards, the authors herein present a procedure developed to predict the vibration levels on ships. This procedure builds on finite element linear dynamic analysis and is applied to predict the vibration levels on a 60 m superyacht considered as a case study. The results of the numerical simulations are then benchmarked against experimental data acquired during the sea trial of the vessel. This analysis also allows the authors to evaluate the global damping ratio to be used by designers in the vibration analysis of superyachts.

Analysis of Three-dimensional Crack Propagation by Using Displacement Discontinuity Method

A technique for modelling of three-dimensional(3D)quasi-statically propagating cracks in elastic bodies by the displacement discontinuity method(DDM)was described.When the crack is closed,the Mohr-coulomb rule on the two contacted surfaces of the crack must be satisfied.A simple iterative method was adopted in order to consider three different states of cracks.Under the assumption that the advance of the point on the crack front would occur only in the normal plane which is through this edge point,the maximum energy release rate criterion is modified to be used as the criterion for the crack growth.With discretization,the process of crack propagation can be seen as the advance of the vertices of the crack front.The program MCP3D was developed based on these theories to simulate the 3D quasi-static crack propagation.A numerical example of a penny-shaped crack subject to tension and compression in an infinite elastic media was analyzed with MCP3D,and the results in comparison with others' show that the present method for 3D crack propagation is effective.

Ophthalmic Syndrome Differentiation System and Digital Chinese Medicine

In traditional Chinese medicine(TCM),ophthalmic syndrome differentiation is an ophthalmology-specific method for identifying syndromes based on the“Five Orbiculi”theory.It was devised by Professor Qing-Hua PENG through an unprecedented combination of syndrome element differentiation and ophthalmic clinical practices,based on the Clinical Terminology of Chinese Medical Diagnosis and Treatment-Syndromes of the National Standards of the People's Republic of China.This approach integrates an ophthalmic syndrome differentiation system with digital Chinese medicine(DCM),and proposes the extraction of syndrome elements of ophthalmic diseases from research on DCM.These elements are then quantified and organized to form a model of digital diagnosis and treatment specific to ophthalmology,which should help to achieve synergistic development of the ophthalmic syndrome differentiation system and DCM.

Human Settlement Analysis Based on Multi-temporal Remote Sensing Data： A Case Study of Xuzhou City, China

To evaluate urban human settlement, we propose a human settlement environment development index(HSEDI) model by choosing vegetation coverage, land surface temperature, impervious surfaces, slope, wetness, and water condition as the evaluation factors. We applied the proposed model to Xuzhou City, Jiangsu Province, China. Landsat-5 Thematic Mapper(TM) images from 1998 to 2010 and digital elevation model(DEM) data with a 30-m resolution were used to calculate the values of the six evaluation factors. The HSEDI value in Xuzhou City was found to be between 2.24 and 8.10 from 1998 to 2010, and it was further divided into five levels, uninhabitable, moderately uninhabitable, generally inhabitable, moderately inhabitable, and inhabitable. The best HSEDI value was in 2007. The generally inhabitable region was about 100.98 km^2, covering 30.87% of the total area in 2007; the moderately inhabitable region was about 170.58 km2 covering 52.15% of the total area; the inhabitable region was about 32.03 km^2, covering 9.79% of the total area; the percentage of the uninhabitable region was zero; and that of the moderately uninhabitable region was very small, less than 1.00%. Moreover, we analyzed the habitability in the respect of spatial patterns and change detection. Results show that the degraded regions of habitability quality are mainly located in the urban fringe and the improved regions are mainly located in the main urban and rural areas. Reason for the degraded habitability quality is the rapid progress of urbanization. However, the increase in urban green spaces and the construction of the main urban area promoted the improved habitability quality. Besides, we further analyzed socio-economic and socio-demographic data to confirm the results of the habitability analysis. The results indicate that the human settlement in Xuzhou City is in a satisfactory condition, but some efforts should be made to control the possible uninhabitable and moderately uninhabitable regions, and to improve the quality of the generally inhabitable regions.

New Pseudorandom Number Generator Artin-Sc hreier Tower for p = 5

The standard method to construct a finite field requires a primitive irreducible polynomial of a given degree. Therefore, it is difficult to apply for the construction of huge finite fields. To avoid this problem, we propose a new method to construct huge finite fields with the characteristic p = 5 by using an Artin-Schreier tower. Utilizing the recursive basis of the Artin-Schreier tower, we define a nmltiplication algorithm The algorithm can explicitly calculate the multiplication of two elements on the top finite field of this tower, without any primitive element. We also define a linear recurrence equation as an application, which produces a sequence of numbers, and call the new pseudorandom number generator Abstract Syntax Tree （AST） for p = 5. The experircental results show that our new pseudorandom number generator can produce a sequence of numbers with a long period.