基于粗糙集和证据理论的设备状态评估方法

为准确判定复杂设备健康状态,提出一种基于粗糙集理论和证据理论的健康状态评估方法。鉴于粗糙集只能处理离散指标,首先提出一种基于动态模糊C-均值聚类算法的连续型评估指标的离散化方法;再通过基于互信息的属性约简算法对复杂设备健康状态评估指标进行约简;然后对约简的评估决策表进行处理,构建基本信度分配函数;最后利用D-S合成规则进行多指标合成得到健康状态,进一步挖掘评估指标与健康状态间的关系。实例研究及对比分析表明该方法能有效提高决策可信度,减少评估的不确定性。     

考虑避灾心理和灾害影响的疏散仿真方法

在在灾害发生时,安全高效的疏散人群是提高公共安全的重要保障。因此有效可行的疏散仿真方法具有深刻的理论和现实意义。当前主流方法较少考虑与疏散相关的灾害动态演化,为此提出了DERR(Dynamic Evacuation Route Replanning Based on Psychology)方法。DERR方法围绕人群的避灾心理参数进行相关研究,利用A*寻路算法,实时根据灾害区的变化对人群的疏散路径重新规划和优化,以达到更加安全疏散的目的。通过仿真实验展示了本方法在灾害演化下的疏散模拟过程,同时心理避灾参数的加入也使得仿真结果更加贴合现实。     

Robust stability test for 2-D continuous-discrete systems with interval parameters

It is revealed that the dynamic stability of 2-D recursive continuous-discrete systems with interval parameters involves the problem of robust Hurwitz-Schur stability of bivariate polynomials family. It is proved that the Hurwitz-Schur stability of the denominator polynomials of the systems is necessary and sufficient for the asymptotic stability of the 2-D hybrid systems. The 2-D hybrid transformation, i. e. 2-D Laplace-Z transformation, has been proposed to solve the stability analysis of the 2-D continuous-discrete systems, to get the 2-D hybrid transfer functions of the systems. The edge test for the Hurwitz-Schur stability of interval bivariate polynomials is introduced. The Hurwitz-Schur stability of the interval family of 2-D polynomials can be guaranteed by the stability of its finite edge polynomials of the family. An algorithm about the stability test of edge polynomials is given.     

Optimizing on multiple constrained QoS multicast routing algorithms based on GA

With the rapid development of Internet, mobile networks and high-performance networking technology,multiple constrained QoS multicast routing optimization in networks with uncertain parameters has become a very important research issue in the areas of networks and distributed systems. It is also a challenging and hard problem to the next generation Internet and high-performance networks, and has attracted the interests of many people. This paper discusses the multiple constrained QoS multicast routing problem, which may deal with the delay, delay jitter,bandwidth and packet loss metrics, and describes a network model for researching the routing problem. The paper mainly presents multiple constrained QoS multicast routing algorithm (MCQMRA), a QoS multicast routing policy for Internet,mobile network or other high-performance networks, which is based on the genetic algorithm (GA) and can provide QoS-sensitive paths in a scalable and flexible wayin the network environment with uncertain parameters. The MCQMRA can also optimize the network resources such as bandwidth, delay, packet loss metrics and can converge to the optimal or near-optimal solution within few iterations, even for the network environment with uncertain parameters. Simulation results show that MCQMRA is an available approach to QoS multicast routing decision.     

关于传递性偏好断面规模的比较分析

文章在分析传递性偏好断面规模问题的起源的基础上，探讨满足Coombs条件和Black条件的传递性偏好断面规模问题，通过分析满足Coombs条件和Black条件偏好序的表示形式，给出Coombs条件和Black条件下的传递性偏好断面规模的计算式，并对满足Coombs条件和Black条件的传递性偏好断面规模进行比较，所得结论表明：Coombs条件和Black条件虽能确保过半数规则的有效性，但却限制了个体的自由选择，但与Coombs条件相比，Black条件对个体自由选择的约束相对较弱。     

Multi-target localization for bistatic MIMO radar in the presence of unknown mutual coupling

A decoupling-estimation signal parameters via rotarional invariance technique(ESPRIT) method is presented for multi-target localization with unknown mutual coupling in bistatic multiple-input multiple-output(MIMO) radar.Two steps are carried out in this method.The decoupling operation between angle and mutual coupling estimates is realized by choosing the auxiliary elements on both sides of the transmit and receive uniform linear arrays(ULAs).Then the ESPRIT method is resilient against the unknown mutual coupling matrix(MCM) and can be directly utilized to estimate the direction of departure(DOD) and the direction of arrival(DOA).Moreover,the mutual coupling coefficient is estimated by finding the solution of the linear constrained optimization problem.The proposed method allows an efficient DOD and DOA estimates with automatic pairing.Simulation results are presented to verify the effectiveness of the proposed method.     

基于延时相关处理的ESPRIT算法

为了提高旋转不变子空间(estimation of signal parameters via rotational invariance techniques, ESPRIT)算法的分辨力和测角精度,充分利用非零延迟相关函数中信号入射角度的信息,提出了基于延时相关处理的ESPRIT算法。根据所有阵列间延时相关信息,构造新的阵列输出矩阵,并且得到新的协方差矩阵。对新的协方差矩阵进行特征值分解得到特征向量,通过将特征向量划分得到含有入射角度信息的子阵,最终求得信源的入射角度。仿真结果表明,该算法的分辨力和测角精度均优于原ESPRIT算法,并且在小角度间距情况下也有较好的分辨性能。     

调制型光纤捷联系统系泊状态标校方法

针对舰船系泊状态特有的运动环境及惯性器件偏差对捷联系统导航精度的影响,提出一种单轴四位置旋转调制方案并建立该系统误差方程。研究了直观分析系统参数可观测性的解析方法,并运用谱条件数法计算出惯性测量单元（inertial measurement unit, IMU）在静止和旋转状态下各状态量的可观测度,利用分离位置回路的卡尔曼滤波模型实现了器件偏差的现场估计。数值仿真显示,单轴四位置转停方案可以有效地提高惯性器件偏差的可观测度,大大提高了系泊状态下惯性器件偏差的估计精度。     

引战配合可视化仿真命中点参数精确计算

在传统的引战配合仿真中一般采用简化目标模型通过概率密度积分的方法求命中点参数,计算精度和实时性较差,而且无法计算各命中破片的落速、落角、命中部位等具体参数。推导了一种精确计算命中点参数的算法,可以有效克服传统命中点参数计算方法的不足,能够满足引战配合可视化仿真的需要。本算法已成功应用于多种引战系统的可视化仿真软件中。     

钻柱、钻头与岩石系统计算机仿真

国内外在研究钻柱振动时都把钻柱下端当作铰支,假设激振源为周期性的,偏离实际。本文从建立符合实际的下端边界条件入手,着重研究了钻柱的纵向振动。用有限单元法,求出整体质量、整体刚度,整体阻尼矩阵采用的是比例阻尼矩阵,利用牛顿法得到钻柱的振动方程,另外通过钻头与岩石的相互作用模型得到了真实的钻柱下端边界条件,并利用Ｈｏｕｂｏｌｔ软件,并进行了大量仿真实验,通过对实验结果分析得到了有意义的结论。