基于CPN的TDRS操作规划建模与仿真

以中继卫星(Racking and Data Relay Satellite,TDRS)为研究对象,以有色Petri网(Colored Petri Net,CPN)为数学工具,根据自顶向下的原则和层次化建模思想,提出一种基于CPN的TDRS操作规划模型,该模型分为顶层模型、控制模型、前向链路数据接收任务与发送任务的操作规划模型和返向链路数据接收任务与发送任务的操作规划模型,有效地描述了TDRS的动态行为特性。最后,通过仿真实验得到了TDRS操作规划方案,验证了所建模型的有效性。与PDDL模型比较分析表明:所建模型可以有效引入TDRS的领域知识,能够有效提高求解效率。所建模型可以为TDRS操作规划方案的制定提供理论参考。     

面向任务的战术行动自主协同关系模型

在信息化战争的大背景下,战术行动中团队协同作战一直是研究的重点问题,而如何建立自主协同关系是团队协同研究的一个难点问题。在分析已有团队协同理论和框架的基础上,提出一种面向任务的战术行动自主协同关系模型建立方法。该模型首先根据当前战场态势和上级任务发布自主协同任务集合,各作战单元根据战场态势和自主决策自愿参与自主协同任务,其次利用作战单元与自主协同任务间的相互关系实现对关键角色的判断。如果关键协同成员参与自主协同任务则自主协同关系建立成功,反之,建立失败。     

基于移相器控制电压的“动中通”波束形成改进算法

在波束形成技术中,基于同时扰动随机梯度估计算法计算接收功率对移相器控制电压的梯度,研究了同时扰动随机梯度估计算法中扰动量和电压更新方程中步长的取值问题。仿真结果表明,随迭代次数变化的扰动量较固定扰动量能有效地提高算法的收敛性能,在同时扰动随机梯度估计算法中,将步长改为随阵元空间位置变化,能有效地提高电压更新方程的收敛速度。研究了与变扰动量有关的参数取值,指出了参数的选取准则。MATLAB仿真结果验证了所改进算法的正确性和有效性。     

Planning for the next Takur Ghar

The USA is currently facing an increasingly diverse range of threats, including non-state actors, particularly violent extremist organizations attempting to do harm. The national leadership has made it clear that for the near future it will employ Special Operations Forces (SOF) as the tool of choice in short-duration, high-intensity operations that have more in common with the battle of Takur Ghar, than those with a larger footprint. It is critical then that the lessons of the past are learnt now and are applied before employing SOF in the future. This becomes especially important given the short lead-time in concert with the short-duration/high-intensity tempo of their operations. In the Battle of Takur Ghar, during Operation Anaconda, rigid adherence to the joint functions, especially clearer and more robust Command and Control (C2) and Intelligence, Surveillance, and Reconnaissance (ISR) in the planning and execution of Operation Anaconda would have yielded a better operational outcome and saved lives. With the benefit of hindsight, many things could have been done differently, but several key issues stand out. The C2 structure must include all components from the outset to synchronize effects and rapidly re-task ISR. There must be multiple communications redundancies and adequate bandwidth. Finally, all SOF, conventional and interagency capabilities must be synchronized under one task force commander with a sufficiently robust C2 infrastructure to direct the entire effort. As our nation calls on SOF at an ever-increasing rate, we must take those lessons learned and apply them to future operations.     

How and why Boko Haram blossomed: examining the fatal consequences of treating a purposive terrorist organisation as less so

Boko Haram (BH) is an insurgent group that operates mainly in northeastern Nigeria. Its stated aim is to establish an Islamic state, and it employs terrorism as its strategy. Earlier interests of security analysts centred on the drivers of BH uprising and the possibility of its internationalisation. Today's concerns relate more to why the rebellion has lasted this long. In toeing the same line, this article demonstrates that BH is a purposive terror group against which the government has evolved no viable strategy. It examines some gains of BH over the past six years and how it benefitted from the government's underestimation of its capacity and determination. It concludes that to effectively engage BH, the Nigerian government must revaluate its threat and sincerely pursue an expanded strategy beyond the current military-centric approach. To be effective, government's response must be packaged in such a way as to enhance human security in the region.     

喷气燃料中特征真菌Amorphotheca resinae的生物学性状研究

通过提供不同的碳源对喷气燃料中检测出的特征真菌Amorphotheca resinae(A.resinae)进行培养,观察菌落和孢子形态,研究其生物学性状;在液体培养基中对其进行振荡培养时出现了油包水现象,从而对特征真菌污染过的油、水相进行表面张力测定。研究结果表明:A.resinae在固体培养基中生长缓慢且出现角变现象;孢子直径仅约1μm;被特征真菌污染过的水相表面张力降低,推测培养A.resinae时可能产生了生物表面活性物质。     

科氏流量计信号相位差测量新算法

对科氏流量计信号进行处理时,传统相位差测量算法存在较大误差。为更好地抑制频谱泄露,提高相位差测量精度,在传统DTFT算法的基础上,通过矩形窗和汉宁窗卷积运算构造出一种新窗——RHC窗。计及负频率成分的影响,提出了一种基于RHC窗的DTFT相位差测量新算法。详细阐述了新算法的原理,并与传统DTFT算法进行了对比仿真,验证了新算法的有效性。     

块Toeplitz矩阵低复杂度求逆的卫星导航空时抗干扰算法

采样协方差矩阵求逆是空时抗干扰算法的基本运算单元,但由于其运算量随时域抽头个数急剧增长,直接限制了空时抗干扰技术在卫星导航接收机中的应用。针对该问题,提出了基于块Toeplitz矩阵快速求逆的空时抗干扰方法。通过采用新的协方差矩阵近似计算方法,使得该矩阵同时为块Toeplitz矩阵与Hermite矩阵,并运用块Toeplitz矩阵的快速求逆算法,将时域抽头个数为K的计算复杂度从O[K3]降至O[K2]。理论分析和仿真结果表明,在阵元数为4、时域抽头为15的典型情况下,相比现有矩阵求逆方法,该算法的抗干扰性能损耗小于1d B,但计算量可降低约2/3。     

“算法战争”的概念、特点与影响

分析了"算法战争"的概念,考察了美军围绕筹划"算法战争"所展开的相关举措,讨论了"算法战争"的潜在影响,并指出了其局限性所在。建议跟踪研判"算法战争"的未来演变趋势,依托军民融合加强算法储备,重视反制措施的研究和伦理探讨。     

基于灰色预测的时敏军事任务调度模型

为有效利用栅格化军事信息系统硬件冗余资源,提高系统运行时效,保证时敏军事任务执行效果,基于灰色理论的GM(1,1),提出了一种时敏军事任务调度模型。构建了基于主动式主/副本机制的调度流程,并针对普通(阈值)调度模型和模糊控制调度模型中调度触发的滞后和调度价值不确定的问题,设计了预测型调度时间窗口,有效优化了调度触发机制。最后通过仿真实验,考察了3种调度模型的有效性,结果表明模型虽然耗费了较大的调度开销,但在降低总体任务用时上作用明显。