固定翼无人机航迹跟踪抗风性研究

无人机作为一种新型军事装备,具有广泛的作战应用场景。无人机的航迹跟踪性能和抗干扰能力是其安全完成飞行任务的保障,随着现代战争作战环境日益复杂,无人机飞行将面临更大的挑战。针对目前固定翼无人机在飞行过程中受风扰影响严重的问题,设计了一种具有抗风性的航迹跟踪方法。利用非线性导引原理实现对航迹的跟踪,并通过引入反馈消除了风扰条件下飞行轨迹与期望航迹之间存在的静差。最后通过仿真验证了该方法的可行性和有效性。     

地球静止轨道航天器绕飞持续观测任务轨迹规划与控制

针对地球静止轨道(geosynchronous orbit, GEO)航天器的高清观测任务,成像卫星在连续小推力作用下接近GEO航天器,对GEO航天器自然绕飞并以有利的光照条件对其持续观测。针对Clohessy-Wiltshire (CW)方程的偏差问题,通过修正非球形摄动和重力加速度二次长期项偏差对CW方程进行改进,补偿非线性偏差的长期项和主要的摄动项。在轨迹规划问题上,计算绕飞轨迹的初始相位角区间,以保证成像卫星在整个绕飞任务中都能够以良好的观测角观测GEO航天器。基于CW方程和改进的CW方程对成像卫星接近和绕飞GEO航天器全过程进行仿真,基于CW方程的仿真没有达到预期目标;基于改进的CW方程的仿真达到预期目标,全过程所需施加的总速度增量仅为4.67 m/s,工程上具有很强的可行性。     

纯方位目标运动分析四维状态的最小二乘模型及分析

建立了纯方位系统TMA四维状态的最小二乘模型,详细给出了非线性最小二乘算法的迭代公式,分析了非线性最小二乘模型、线性最小二乘模型可解的必要条件,以及非线性最小二乘模型与极大似然模型的等价性。     

Two-agent scheduling with linear resource-dependent processing times

This paper considers a two-agent scheduling problem with linear resource-dependent processing times, in which each agent has a set of jobs that compete with that of the other agent for the use of a common processing machine, and each agent aims to minimize the weighted number of its tardy jobs. To meet the due date requirements of the jobs of the two agents, additional amounts of a common resource, which may be in discrete or continuous quantities, can be allocated to the processing of the jobs to compress their processing durations. The actual processing time of a job is a linear function of the amount of the resource allocated to it. The objective is to determine the optimal job sequence and resource allocation strategy so as to minimize the weighted number of tardy jobs of one agent, while keeping the weighted number of tardy jobs of the other agent, and the total resource consumption cost within their respective predetermined limits. It is shown that the problem is -hard in the ordinary sense, and there does not exist a polynomial-time approximation algorithm with performance ratio unless ; however it admits a relaxed fully polynomial time approximation scheme. A proximal bundle algorithm based on Lagrangian relaxation is also presented to solve the problem approximately. To speed up convergence and produce sharp bounds, enhancement strategies including the design of a Tabu search algorithm and integration of a Lagrangian recovery heuristic into the algorithm are devised. Extensive numerical studies are conducted to assess the effectiveness and efficiency of the proposed algorithms.     

Dynamic evacuation routes for personnel on a naval ship

We propose a dynamic escape route system for emergency evacuation of a naval ship. The system employs signals that adapt to the causative contingency and the crew's physical distribution about the ship. A mixed‐integer nonlinear programming model, with underlying network structure, optimizes the evacuation process. The network's nodes represent compartments, closures (e.g., doors and hatches) and intersections, while arcs represent various types of passageways. The objective function integrates two potentially conflicting factors: average evacuation time and the watertight and airtight integrity of the ship after evacuation. A heuristic solves the model approximately using a sequence of mixed‐integer linear approximating problems. Using data for a Spanish frigate, with standard static routes specified by the ship's designers, computational tests show that the dynamic system can reduce average evacuation times, nearly 23%, and can improve a combined measure of ship integrity by up to 50%. In addition, plausible design changes to the frigate yield further, substantial improvements. Published 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008     

坦克炮控伺服系统的滑模非线性摩擦补偿控制

坦克炮控伺服系统存在低速摩擦,摩擦环节不但造成系统的稳态误差,而且导致极限环振荡、低速爬行等现象.提出基于Lyapunov稳定理论的滑模控制方法,通过 Lyapunov稳定理论获得控制量,同时克服参数不确定性和补偿非线性摩擦力矩,从而保证跟踪误差渐进收敛.仿真结果表明该设计方法大大优于经典设计,为炮控伺服系统实际设计提供了一种可行的新方法.     

就业与社会稳定的关联性探析

就业与社会稳定的正相关：就业的保障功能的发挥、激励功能的发挥、融入功能的发挥、协作功能的发挥,都有助于实现社会稳定。就业存在的问题与社会稳定的负相关：失业人员大量存在、就业弱势群体大量存在、就业权益缺失,都影响着社会稳定。     

建筑消防水系统工程施工存在的问题及建议

针对近年来对一些建筑消防设施水系统工程的中期检查和工程消防验收．以及对投入使用后的建筑进行消防监督检查中发现的建筑消防设施水系统工程存在的一些施工质量问题,在依据有关消防技术性规范的基础上,查找根源,提出几点建议。     

建立维和警察心理调控机制之我见

联合国维和警察是一个特殊的职业群体,所处的工作和生活环境艰苦、恶劣、危险。维和警察面对这种超出常规的精神压力,出现各种各样的心理问题是必然的。维和警察的心理问题仅仅依靠维和警察个人自我调节是远远不够的,必须建立一套有效的调控机制来预防和治疗其心理问题,维护好他们的心理健康。     

打击特殊群体贩毒活动现状及对策研究

近年来,随着我国堵截、打击毒品犯罪力度的持续加大,境内外贩毒集团组织实施大宗毒品贩运的能力明显减弱,毒品犯罪快速蔓延的势头得到初步遏制。但是,贩毒集团为逃避打击、降低风险,不断变换犯罪手法,钻法律漏洞,特别是组织、利用特殊人群进行贩毒活动的现象日益增多,并呈现出家族化、规模化的趋势,而公安机关在打击特殊群体贩毒活动中,由于立法和执法等多方面的原因,还面临法律、查缉、羁押、案件处理等一系列的问题。执法实践要求运用法律、经济、行政、教育、文化等措施,综合治理特殊群体贩毒问题,努力从源头上遏制特殊人群贩毒问题的滋生、蔓延。