Minimum fractional dominating functions and maximum fractional packing functions

The fractional analogues of domination and 2-packing in a graph form an interesting pair of dual linear programmes in that the feasible solutions for both are functions from the vertices of the graph to the unit interval; efficient (fractional) domination is accomplished when one function simultaneously solves both LPs. We investigate some structural properties of the functions thus defined and classify some families of graphs according to how and whether the sets of functions intersect, developing tools that have proven useful in approaching problems in domination theory.     

Microwave complementary doped-channel field-effect transistors

In this paper, the device performance and complementary inverter of the InGaP/InGaAs/GaAs doped-channel field-effect transistors (DCFETs) by two-dimensional semiconductor simulation are demonstrated. Due to the relatively large conduction (valance) band discontinuity at InGaP/InGaAs interface, it provides good confinement effect for transporting carriers in InGaAs channel layer for the n-channel (p-channel) device. The large gate turn-on voltage is achieved due to the employment of the wide energy-gap InGaP material as gate layer. The _ft$f_t$ and _fmax$f_{max}$ are of 6.5 (2.1) and 25 (5) GHz for the n-channel (p-channel) device. Furthermore, the co-integrated structures, by the combination of n- and p-channel field-effect transistors, could form a complementary inverter and the relatively large noise margins are achieved.     

ZnCuInS/ZnS量子点与Poly-TPD补偿发光光谱的研究

ZnCuInS/ZnS量子点是一种无重金属、“绿色”半导体纳米材料。在研究中,制备出尺寸为3.2 nm的ZnCuInS/ZnS核壳量子点,并说明它是施主-受主对复合发光。通过测量ZnCuInS/ZnS量子点的光致发光光谱,其发射峰值波长为620 nm、半宽度是95 nm的红光。同时,还制备出Poly-TPD有机薄膜,其发光光谱是峰值波长为480 nm的蓝光。所以,ZnCuInS/ZnS量子点和Poly-TPD发光颜色具有互补性。在ZnCuInS/ZnS量子点薄膜层上包覆一层poly-TPD薄膜后,二者发光颜色互补。在恰当的偏置电压下,可以得到较好的白光光谱。计算表明,其色坐标是(0.336,0.339),颜色指数是92。     

带概率判断和模糊区间判断的一种排序算法

对于 AHP中一类判断为模糊、不确定性问题 ,用随机变量和模糊区间描述其判断 ,采用 0 .1～ 0 .9标度 ,建立模糊互补判断矩阵 ,利用数学变换得到模糊一致性判断矩阵 ,给出排序向量算法及公式 ,便于实际应用     

Computation of all solutions to a system of polynomial equations

This paper proposes a homotopy continuation method for approximating all solutions to a system of polynomial equations in several complex variables. The method is based on piecewise linear approximation and complementarity theory. It utilizes a skilful artificial map and two copies of the triangulationJ ₃ with continuous refinement of grid size to increase the computational efficiency and to avoid the necessity of determining the grid size a priori. Some computational results are also reported.     

Partial pivoting strategies for symmetric gaussian elimination

In an earlier paper [6] it is shown how the use of symmetric additions of rows and columns enables a stableLDL ^T factorization of symmetric indefinite matrices. In this paper we describe partial pivoting strategies. These strategies are faster than the complete pivoting strategies that were introduced in the first paper. Numerical experiments are included. The results show that some of the new strategies share the stable behaviour of complete pivoting while running almost as fast as the well-known Cholesky decomposition.     

Construction of uniform designs without replications

A uniform design scatters its design points evenly on the experimental domain according to some discrepancy measure. In this paper all the design points of a full factorial design can be split into two subdesigns. One is called the complementary design of the other. The complementary design theories of characterizing one design through the other under the four commonly used discrepancy measures are investigated. Based on these complementary design theories, some general rules for searching uniform designs through their complementary designs are proposed. An efficient method to check if a design has repeated points is introduced and a modified threshold-accepting algorithm is proposed to search uniform or nearly uniform designs without replications. The new algorithm is shown to be more efficient by comparing with other existing methods. Many new uniform or nearly uniform designs without replications are tabulated and compared.     

一种多滤波器组合导航数据融合方法

针对组合导航系统中使用单天线GPS接收机时导致姿态角不易收敛的问题,提出了一种互补滤波器和卡尔曼滤波器相结合的数据融合算法。该方法首先通过MEMS惯性传感器与磁强计设计了一种互补滤波算法。针对载体在变速运动过程中加速度计的倾角测量值有较大误差,影响互补滤波器输出精度的问题,通过GPS接收机和加速度计设计了卡尔曼滤波模型,将卡尔曼滤波器输出速度的微分量反馈给互补滤波器,实现了对互补滤波器中载体运动加速度的补偿。基于以上解算方法,以FPGA为核心处理器设计了组合导航系统并进行了车载实验。实验中,该方法有效补偿了汽车变速过程中的倾角测量误差,证明了该方法的有效性。