LIMITING DIRECTION AND BAKER WANDERING DOMAIN OF ENTIRE SOLUTIONS OF DIFFERENTIAL EQUATIONS

In this paper, we mainly investigate entire solutions of complex differential equations with coefficients involving exponential functions, and obtain the dynamical properties of the solutions, their derivatives and primitives. With some conditions on coefficients, for the solutions, their derivatives and their primitives, we consider the common limiting directions of Julia set and the existence of Baker wandering domain.

Direction-of-arrival estimation based on direct data domain (D3) method

A direction-of-arrival （DOA） estimation algorithm based on direct data domain （D3） approach is presented. This method can accuracy estimate DOA using one snapshot modified data, called the temporal and spatial two-dimensional vector reconstruction （TSR） method. The key idea is to apply the D3 approach which can extract the signal of given frequency but null out other frequency signals in temporal domain. Then the spatial vector reconstruction processing is used to estimate the angle of the spatial coherent signal source based on extract signal data. Compared with the common temporal and spatial processing approach, the TSR method has a lower computational load, higher real-time performance, robustness and angular accuracy of DOA. The proposed algorithm can be directly applied to the phased array radar of coherent pulses. Simulation results demonstrate the performance of the proposed technique.

Reduction of Residual Stress in Low Alloy Steel with Magnetic Treatment in Different Directions

The behavior that different magnetic treatment directions induce various amounts of welding residual stress reductions in low alloy steel was studied. Reductions of 26%-28% in the longitudinal stress σ x were obtained when low frequency alternating magnetic treatment was applied perpendicularly to the welding bead, whereas reductions of 20%-21% in σ x were measured by using the same treatment parameters except that the field direction was applied parallel to the bead. It is proposed that different extent of stress reductions caused by the above two treatment directions is attributed primarily to the alteration of the energy absorbed by domains from the external magnetic field, which part of energy can arouse plastic deformation in microstructures by the motion of domain walls.

Direct data domain approach to space-time adaptive processing

In non-homogeneous environment, traditional space-time adaptive processing doesn＇t effectively suppress interference and detect target, because the secondary data don＇ t exactly reflect the statistical characteristic of the range cell under test. A ravel methodology utilizing the direct data domain approach to space-time adaptive processing （ STAP ） in airbome radar non-homogeneous environments is presented. The deterministic least squares adaptive signal processing technique operates on a ＂snapshot-by-snapshot＂ basis to dethrone the adaptive adaptive weights for nulling interferences and estimating signal of interest （SOI）. Furthermore, this approach eliminates the requirement for estimating the covariance through the data of neighboring range cell, which eliminates calculating the inverse of covariance, and can be implemented to operate in real-time. Simulation results illustrate the efficiency of interference suppression in non-homogeneous environment.

A Novel Direct Anonymous Attestation Protocol Based on Zero Knowledge Proof for Different Trusted Domains

In order to solve the issue that existing direct anonymous attestation (DAA) scheme can not operate effectively in different domains,based on the original DAA scheme,a novel direct anonymous attestation protocol used in multi domains environment is proposed and designed,in which,the certificate issuer located in outside of domain can be considered as a proxy server to issue the DAA certificate for valid member nodes directly.Our designed mechanism accords with present trusted computing group (TCG) international specification,and can solve the problems of practical authentication and privacy information protection between different trusted domains efficiently.Compared with present DAA scheme,in our protocol,the anonymity,unforgeability can be guaranteed,and the replay-attack also can be avoided.It has important referenced and practical application value in trusted computing field.

BOREL'S DIRECTIONS AND SHARED VALUES

In this article, we study the problems of Borel＇s directions of meromorphic func- tions concerning shared values and prove that if two meromorphie functions of infinite order share three distinct values, their Borel＇s directions are same.

Three-dimensional transformation of magnetization direction and magnetic field component at low latitudes based on vertical relationship

The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial domains.The transformation method in the wavenumber domain has simpler processing expression and higher processing effi ciency than in the spatial domain;however,they are unstable at low latitude.In this paper,the conclusion that the sum is 0 of two vertical magnetic fi eld components(magnetization inclinations are also perpendicular)in 2D is used for the 3D transformation of the magnetization direction and the magnetic field component.In addition,the transformation method at low latitudes based on vertical relationship(VMT)is proposed,which is an iterative algorithm that converts the transformation of the magnetization direction and the magnetic field component at the low latitude into the high latitude.This method restrains the instability of transformation of constant and variable magnetization direction and magnetic fi eld components in low latitudes.The accuracy,stability,and practicality are verifi ed from synthetic models and real data.

A ROBUST PHASE-ONLY DIRECT DATA DOMAIN ALGORITHM BASED ON GENERALIZED RAYLEIGH QUOTIENT OPTIMIZATION USING HYBRID GENETIC ALGORITHM

A robust phase-only Direct Data Domain Least Squares (D3LS) algorithm based on gen- eralized Rayleigh quotient optimization using hybrid Genetic Algorithm (GA) is presented in this letter. The optimization efficiency and computational speed are improved via the hybrid GA com- posed of standard GA and Nelder-Mead simplex algorithms. First, the objective function, with a form of generalized Rayleigh quotient, is derived via the standard D3LS algorithm. It is then taken as a fitness function and the unknown phases of all adaptive weights are taken as decision variables. Then, the nonlinear optimization is performed via the hybrid GA to obtain the optimized solution of phase-only adaptive weights. As a phase-only adaptive algorithm, the proposed algorithm is sim- pler than conventional algorithms when it comes to hardware implementation. Moreover, it proc- esses only a single snapshot data as opposed to forming sample covariance matrix and operating matrix inversion. Simulation results show that the proposed algorithm has a good signal recovery and interferences nulling performance, which are superior to that of the phase-only D3LS algorithm based on standard GA.

Directed Evolution of L-Aspartase by Mobility of Domains

To enhance the relative movement of domains, we inserted a random sequence of fifteen-peptide into the three domains of L-aspartase. By means of directed screening, the three isoforms of monomeric, dimmeric and tetrameric enzymes were obtained. Compared to the wild-type tetrameric L-asparease, these mutants remained 19.7%, 42.3%, and 92% of the enzyme activity, respectively. Moreover, the examination of enzyme properties revealed that their k_ cat and K_M changed in varying degrees, and the optimum pH shifted towards acidic pH, while the dependence of the activity of enzyme on Mg 2+ concentration and thermostability increased. Therefore this strategy provides a novel approach to directed evolution of enzymes.

Goal-oriented error estimation applied to direct solution of steady-state analysis with frequency-domain finite element method

Based on the concept of the constitutive relation error along with the residuals of both the origin and the dual problems, a goal-oriented error estimation method with extended degrees of freedom is developed. It leads to the high quality locM error bounds in the problem of the direct-solution steady-state dynamic analysis with a frequency-domain finite element, which involves the enrichments with plural variable basis functions. The solution of the steady-state dynamic procedure calculates the harmonic response directly in terms of the physical degrees of freedom in the model, which uses the mass, damping, and stiffness matrices of the system. A three-dimensional finite element example is carried out to illustrate the computational procedures.

相容连续Domain的序同态扩张

对相容Domain引入了相容定向极小集的概念,证明了相容Domain D是相容连续Domain当且仅当D中的每个元在D中存在相容定向极小集,并给出了相容连续Domain的序同态扩张定理.

L-Fuzzy Domain及其相关性质

基于[5]提出的L-fuzzy拟序集,引入L-fuzzy集关于L-fuzzy偏序的并,当L是完全分配格时L-fuzzy拟序集上的L-fuzzy定向集等概念,在此基础上定义L-fuzzydomain,证明它是通常Domain的模糊推广,并得到若干相关性质。

稀疏线阵宽带波数域反卷积波束形成栅瓣抑制方法

为解决稀疏线列阵的栅瓣与宽带Richardson-Lucy(R-L)反卷积处理生成点扩散函数(PSF)字典计算量大的问题,提出一种宽带波数域的R-L反卷积波束形成栅瓣抑制方法。该方法利用宽带波数域波束形成在波数域的恒束宽特点,使所有频点的反卷积计算共用一个PSF字典,减少反卷积计算的PSF存储空间和计算量;结合在波数域波束形成算法的栅瓣与主瓣之间存在周期平移关系,利用实际波束形成主瓣方位、宽度以及能量对栅瓣进行基于实际数据的宽带栅瓣预测和抑制,可以获得好的抑制效果。通过仿真和海试数据验证了所提方法的性能,结果表明该方法相较于常规宽带反卷积处理可以减少计算量,栅瓣抑制效果大于6 dB,拓展了相同阵元数情况下阵列对宽带目标的探测分辨性能。

经二极管整流并网的构网型风机大扰动建模与稳定性分析

二极管整流单元型高压直流(DRU-HVDC)送出系统因其经济性优势,在新能源基地直流送出领域具有良好的应用前景。然而,在当前构网型换流器的大扰动稳定性研究中,大多由大容量同步机或大电网支撑故障点的频率和相位,且查表式设定故障电流参考值,缺乏对构网型风机接入DRU-HVDC系统这类故障点频率由换流器控制主导且动态调整故障电流参考值系统的研究。为解决上述问题,首先,建立计及电流限幅和频率控制的高阶非线性微分方程模型;然后,推导故障后系统平衡点的解析表达式,并论证采用q轴优先的电流限幅策略和频率控制在保障大扰动后平衡点存在性方面的优势;最后,基于Takagi-Sugeno法构建Lyapunov函数并得到系统的估计吸引域,分析换流器关键控制参数对暂态稳定性的影响,并与PSCAD/EMTDC中仿真算例进行对比,以验证暂态稳定性分析的准确性。

构网型与跟网型混合直驱风电场并网稳定域分析

传统跟网型(GFL)风机并入弱交流电网时存在小信号失稳风险,而构网型(GFM)机组可在一定程度上提升系统的稳定裕度,这将促使未来出现构网型风机与跟网型风机混合的风电场。然而,跟网型与构网型风机的占比不同时,混合风电场的稳定域如何变化值得深入探索。首先,文中建立了跟网型与构网型混合直驱风电场并网系统的详细数学模型,提出了综合考虑稳态运行约束条件和小信号稳定性约束条件的系统并网稳定域计算方法,定量评估了混合直驱风电场在多维约束下的并网稳定运行域。然后,得到了特定风电场出力下混合直驱风电场在不同GFM风机占比时的电网短路比(SCR)可行范围,并进一步探究了风电场出力及风机至公共连接点(PCC)集电线路长度变化时,混合直驱风电场并网稳定域的变化趋势。最后,通过PSCAD/EMTDC下的电磁暂态仿真,验证了所得混合直驱风电场并网稳定域的准确性。

模糊Domain上的模糊序同态及其性质

通过引入模糊定向极小集和模糊Domain的基的概念,证明了模糊定向完备偏序集X是模糊Domain当且仅当X有基当且仅当x∈X,x有模糊定向极小集.基于模糊定向极小集和模糊Domain的基,研究了模糊Domain上的模糊序同态,证明了模糊Domain X的基到模糊Domain Y上的模糊序同态可以唯一扩张为模糊Domain X到模糊Domain Y上的模糊序同态.

Domain上的扩张定理

对定向极小集进行了进一步的研究,给出了Domain中保定向极小集映射与保定向并和《映射之间的等价刻 画及其有关的性质,在此基础上得到了关于保定向极小集映射的两个相应的扩张定理.

FS-相容Domain的定向完备化及相关范畴性质

引入FS-相容Domain概念,研究FS-相容Domain的性质,主要结果有:(1)FS-相容Domain的收缩核与连续函数空间还是FS-相容Domain;(2)FS-相容Domain是有限生成上集,从而是Scott紧的;(3)FS-相容Domain的定向完备化是FS-Domain;(4)有最大元的FS-Domain去掉最大元后是FS-相容Domain;(5)证明了以Scott连续映射为态射,FS-相容Domain为对象的范畴FS-CDOM是笛卡儿闭范畴并以FS-Domain范畴FS-DOM作为满的反射子范畴。

DOA estimation method for wideband signals by sparse recovery in frequency domain

The traditional super-resolution direction finding methods based on sparse recovery need to divide the estimation space into several discrete angle grids, which will bring the final result some error. To this problem, a novel method for wideband signals by sparse recovery in the frequency domain is proposed. The optimization functions are found and solved by the received data at every frequency, on this basis, the sparse support set is obtained, then the direction of arrival (DOA) is acquired by integrating the information of all frequency bins, and the initial signal can also be recovered. This method avoids the error caused by sparse recovery methods based on grid division, and the degree of freedom is also expanded by array transformation, especially it has a preferable performance under the circumstances of a small number of snapshots and a low signal to noise ratio (SNR).

UNIQUENESS OF MEROMORPHIC FUNCTIONS WHOSE NONLINEAR DIFFERENTIAL POLYNOMIALS SHARE ONE VALUE OR HAVE THE SAME FIXED POINTS IN AN ANGULAR DOMAIN

In this article, we study the uniqueness question of nonconstant meromorphic functions whose nonlinear differential polynomials share 1 or have the same fixed points in an angular domain. The results in this article improve Theorem 1 of Yang and Hua [26], and improve Theorem 1 of Fang and Qiu [6].