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排序方式: 共有7901条查询结果,搜索用时 15 毫秒
51.
军事概念模型建模是作战复杂系统建模与仿真的重要环节。该文提出了一种包含面向过程任务空间概念建模与面向对象仿真空间建模两个阶段的军事概念模型建模方法。该方法方便军事人员与仿真人员从不同视角对作战系统进行抽象描述。最后,该文通过一个空基反导作战案例,对这一方法进行了验证。  相似文献   
52.
Traditional orthogonal strapdown inertial navigation sys-tem (SINS) cannot achieve satisfactory self-alignment accuracy in the stationary base: taking more than 5 minutes and al the iner-tial sensors biases cannot get ful observability except the up-axis accelerometer. However, the ful skewed redundant SINS (RSINS) can not only enhance the reliability of the system, but also improve the accuracy of the system, such as the initial alignment. Firstly, the observability of the system state includes attitude errors and al the inertial sensors biases are analyzed with the global perspective method: any three gyroscopes and three accelerometers can be assembled into an independent subordinate SINS (sub-SINS);the system state can be uniquely confirmed by the coupling connec-tions of al the sub-SINSs;the attitude errors and random constant biases of al the inertial sensors are observable. However, the ran-dom noises of the inertial sensors are not taken into account in the above analyzing process. Secondly, the ful-observable Kalman filter which can be applied to the actual RSINS containing random noises is established; the system state includes the position, ve-locity, attitude errors of al the sub-SINSs and the random constant biases of the redundant inertial sensors. At last, the initial self-alignment process of a typical four-redundancy ful skewed RSINS is simulated: the horizontal attitudes (pitch, rol ) errors and yaw error can be exactly evaluated within 80 s and 100 s respectively, while the random constant biases of gyroscopes and accelero-meters can be precisely evaluated within 120 s. For the ful skewed RSINS, the self-alignment accuracy is greatly improved, mean-while the self-alignment time is widely shortened.  相似文献   
53.
Spiking neural P systems with anti-spikes (ASN P systems) are variant forms of spiking neural P systems, which are inspired by inhibitory impulses/spikes or inhibitory synapses. The typical feature of ASN P systems is when a neuron contains both spikes and anti-spikes, spikes and anti-spikes wil immediately annihilate each other in a maximal way. In this paper, a restricted variant of ASN P systems, cal ed ASN P systems without anni-hilating priority, is considered, where the annihilating rule is used as the standard rule, i.e., it is not obligatory to use in the neuron associated with both spikes and anti-spikes. If the annihilating rule is used in a neuron, the annihilation wil consume one time unit. As a result, such systems using two categories of spiking rules (identified by (a, a) and (a,a^-)) can achieve Turing completeness as number accepting devices.  相似文献   
54.
Quite often over the last decade, heavy equipment manufacturers are trying to improve their project management performance with the use of effective project management methods. However, the challenges encountered aren’t isolated problems and a systemic approach is required. This paper exemplifies how a systemic approach can be applied to heavy equipment manufacturing project (HEMP) management, through of a multifaceted vision. The findings present in the paper are based on a two-year case study in a metallurgic equipment manufacturing enterprise in China. Based on the analysis of HEMP management problems and the contributions on systemic approach application in project management, the paper enriches existing theory by: (1) interpreting the HEMP management system with the top-down disassembly method; (2) developing the collaborative project management approach with a systems view highlighting the project characteristics management and inter-departmental collaboration; (3) making suggestions for systemic approach application in project management. For practitioners and researchers, the findings are particularly meaningful for manufacturing project management and systemic approach application.  相似文献   
55.
一种改进的三角模糊数互补判断矩阵的排序方法   总被引:2,自引:0,他引:2  
在传统的三角模糊数互补判断矩阵排序方法的基础上,结合三角模糊数均值的概念,提出了一种改进的排序方法。该方法通过三角模糊数互补判断矩阵以及相应的概率分布矩阵,计算得到模糊均值矩阵,从而将三角模糊数互补判断矩阵的排序问题转换为模糊均值矩阵的排序问题,然后对模糊均值矩阵利用权的最小平方法计算排序向量。通过计算三角模糊数均值,有效地减少了判断过程中的不确定性。给出了该方法的具体应用步骤,仿真算例表明该方法易于实现,具有很好的可操作性。  相似文献   
56.
针对我国嫦娥二号卫星拓展任务需求,研究了卫星由日地L2点向L1点的转移轨道方案。基于卫星真实星历,考虑各种摄动因素,借助不变流形理论和微分修正方法,设计了嫦娥二号在日地平动点L1和L2之间的转移轨道,提出了便于理解和工程应用的平动点间直接转移方式,研究了真实力模型下平动点Lissajous轨道的不变流形转移方式,对比了两种转移方式的出发速度增量、转移时间与出发时刻的关系。研究表明,嫦娥二号可以通过直接转移方式或者借助不变流形进入日地L1点Lissajous轨道,直接转移方式下有42天出发机会,基于不变流形方式下最短转移时间为210天,对应速度增量5.776 m/s,最小速度增量可达0.024 m/s。研究结果可直接应用于我国嫦娥二号拓展任务的轨道设计与控制,并为我国后续平动点等深空探测任务提供有益借鉴.  相似文献   
57.
狼群算法(wolf pack algorithm, WPA)源于狼群在捕食及其猎物分配中所体现的群体智能,已被成功应用于复杂函数求解。在此基础上,通过定义运动算子,对人工狼位置、步长和智能行为重新进行二进制编码设计,提出了一种解决离散空间组合优化问题的二进制狼群算法(binary wolf pack algorithm, BWPA)。该算法保留了狼群算法基于职责分工的协作式搜索特性,选取离散空间的经典问题--0-1背包问题进行仿真实验,具体通过10组经典的背包问题算例和BWPA算法与经典的二进制粒子群算法、贪婪遗传算法、量子遗传算法在求解3组高维背包问题时的对比计算,例证了算法具有相对更好的稳定性和全局寻优能力。  相似文献   
58.
支持风险投资的政策体系和制度设计研究   总被引:1,自引:0,他引:1  
风险投资产业的蓬勃发展,需要政府部门的大力支持和推进。首先对现有国内外支持风险投资的政策进行了分析和评价,进而探讨了促进风险投资的制度设计。通过整合一系列的资源要素,形成系统化的制度环境,我国未来的风险投资产业将能够获得长足的发展。  相似文献   
59.
量子密钥分发和量子隐形传态不断取得的新突破,使量子通信实用化问题日益成为关注的焦点。本文简析了量子通信研究的发展历程,并对量子通信的实用化现状进行了概括:实用化量子密钥分发技术已近在眼前,但量子隐形传态的实用化仍尚需时日。针对认识和理解量子通信时的典型误区,本文做了简要澄清。根据量子通信实用化发展态势,为我国量子通信的发展提出了4点对策和建议  相似文献   
60.
Chen  Haitao  Song  Shenmin 《系统科学与复杂性》2019,32(6):1597-1629
This paper addresses the attitude tracking control problem of a rigid spacecraft in the presence of the modeling uncertainty, external disturbance, and saturated control input by designing two robust attitude tracking controllers. The basic controller is formulated using an integral sliding mode surface which is continuous and provides an asymptotic convergence rate for the closed-loop system. In this case, only the external disturbance with the prior information is considered. Then, to provide a finite time convergence rate and further improve the robustness of the control system under the unknown system uncertainty containing both the modeling uncertainty and external disturbance,a novel integral terminal sliding mode surface(ITSMS) is designed and associated with the continuous adaptive control method. Besides, a command filter is utilized to deal with the immeasurability problem within the proposed ITSMS and an auxiliary system to counteract the input saturation problem. Digital simulations are presented to verify the effectiveness of the proposed controllers.  相似文献   
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