A Class of Real-Time Parallel Combined Methods ofDigital Simulation for Large Systems

In this paper, a class of real-time parallel combined methods (RTPCM) of the digital simulation for a partitioned large system is presented. By means of combination of the parallelism across the system with the parallelism across the method, stiff and non-stiff subsystems are solved in parallel on parallel computer by a parallel Rosenbrock method and a parallel RK method, respectively. Their construction, convergence and numerical stability are discussed, and the digitalsimulation experiments are conducted.

Class of modified parallel combined methods of real-time numerical simulation for a stiff system

A class of modified parallel combined methods of real-time numerical simulation are presented for a stiff dynamic system. By combining the parallelism across the system with the parallelism across the method, and relaxing the dependence of stage value computation on sampling time of input function, a class of modified real-time parallel combined methods are constructed. Stiff and nonstiff subsystems are solved in parallel on a parallel computer by a parallel Rosen-brock method and a parallel RK method, respectively. Their order conditions and convergences are discussed. The numerical simulation experiments show that this class of modified algorithms can get high speed and efficiency.

头颈联合3D-TOF-MRA人工智能辅助压缩感知序列的优化

目的通过比较施加不同加速因子(acceleration factors,AF)的并行采集(parallel imaging,PI)、压缩感知(compressed sensing,CS)、人工智能-压缩感知(artificial intelligence compressed sensing,ACS)技术的头颈联合三维时间飞跃法磁共振血管成像(three-dimensional time-of-fight magnetic resonance angiography,3D-TOF-MRA)的图像质量,选取优化序列。材料与方法前瞻性招募24例健康志愿者,以PI的AF为3(PI 3)、CS的AF分别为4和6(CS 4、CS 6)以及ACS的AF分别为4、6、8、10(ACS 4、ACS 6、ACS 8、ACS 10)进行头颈联合3D-TOF-MRA扫描。扫描时间:PI 3=8 min 40 s;CS 4=6 min 38 s;CS 6=4 min 9 s;ACS 4=5 min 24 s;ACS 6=4 min 30 s;ACS 8=4 min 13 s;ACS 10=3 min 24 s。分别在双侧大脑中动脉(middle cerebral artery,MCA)M1段、双侧颈内动脉(internal carotid artery,ICA)C4段、颈动脉分叉处下5个层面的双侧颈总动脉(common carotid artery,CCA)以及MCA及ICA同一层面的颞叶白质,CCA同一层面的胸锁乳突肌作为背景区域勾画感兴趣区(regions of interest,ROI),记录信号强度(signal intensity,SI)及标准差(standard deviation,SD),从而计算信噪比(signal-to-noise ratio,SNR)与对比噪声比(contrast-to-noise ratio,CNR)。采用四分法和五分法分别对整体图像质量以及颅内动脉、颈部大动脉进行评分。以组内相关系数(intra-class correlation coefficient,ICC)比较两名放射医师之间及同一名放射医师内客观评价结果的一致性,Kappa检验比较两名放射医师之间及同一名放射医师内主观评价结果的一致性,若一致性良好,则选取其中一位医师的客观评分及主观评分进行后续统计分析。采用单因素方差分析或Kruskal-Wallis检验对客观评分以及主观评分进行总体差异比较,若差异具有统计学意义则进行两两比较。结果与PI技术比较显示,ACS 4~ACS 8的SNR_(L-MCA),ACS 8、ACS 10的CNR_(L-MCA),ACS 4、ACS 6、ACS 10的CNR_(R-MCA),ACS 4~ACS 10的SNR_(R-MCA)、SNR_(L-CCA)、CNR_(L-CCA),ACS 6~ACS 10的SNR_(R-CCA)、CNR_(R-CCA)均高于PI 3,差异具有统计学意义(P<0.05)。与CS技术比较显示,ACS 4~ACS 10的SNR_(R-MCA)、CNR_(L-MCA)及CNR_(R-MCA),ACS 4~ACS 8的SNR_(L-MCA)、SNR_(L-CCA)、SNR_(R-CCA)、CNR_(L-CCA)、CNR_(R-CCA)与CS 4差异具有统计学意义(P<0.05),ACS 4~ACS 10的SNR_(L-MCA)、SNR_(R-MCA)、CNR_(L-MCA)、CNR_(R-MCA)、SNR_(L-ICA)、SNR_(R-ICA)、CNR_(L-ICA)、SNR_(L-CCA)、SNR_(R-CCA)、CNR_(L-CCA)、CNR_(R-CCA)与CS 6差异具有统计学意义(P<0.05),均优于CS 4、CS 6。ACS技术之间两两比较,ACS 8的SNR_(L-MCA)高于ACS 10(P<0.05),ACS 8、ACS 10的SNR_(R-CCA)、CNR_(R-CCA)均高于ACS 4(P<0.05),其余差异均无统计学意义(P>0.05)。除颈部大动脉图像外,主观评分统计结果均为ACS 4~ACS 10与CS 6差异具有统计学意义(P<0.05),优于CS 6。结论与PI及CS技术相比,ACS技术拥有更短的扫描时间,更好的图像质量。ACS 8为最优序列,扫描时间比PI 3缩短51%。

Space decomposition based parallelization solutions for the combined finiteediscrete element method in 2D

The combined finiteediscrete element method （FDEM） belongs to a family of methods of computationalmechanics of discontinua. The method is suitable for problems of discontinua, where particles aredeformable and can fracture or fragment. The applications of FDEM have spread over a number of disciplinesincluding rock mechanics, where problems like mining, mineral processing or rock blasting canbe solved by employing FDEM. In this work, a novel approach for the parallelization of two-dimensional（2D） FDEM aiming at clusters and desktop computers is developed. Dynamic domain decompositionbased parallelization solvers covering all aspects of FDEM have been developed. These have beenimplemented into the open source Y2D software package and have been tested on a PC cluster. Theoverall performance and scalability of the parallel code have been studied using numerical examples. Theresults obtained confirm the suitability of the parallel implementation for solving large scale problems. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

Combined method for parallel manipulator configuration design

Configuration design is an essential, creative and decision-making step m parallel manipulator design process, in which modeling and assembly are iterative and trivial. Combined approach with automatic parametric modeling and automatic assembly is proposed for parallel manipulator configuration design. The design process and key techniques, such as configuration design, configuration verification, poses calculation of all parts in parallel manipulator, virtual assembly and etc., are discussed and demonstrated by an example. A software package is developed for parallel manipulator configuration design based on the proposed method with Visual C＋＋ and UG/OPEN on Unigraphics.

High levels of Zinc-α-2-Glycoprotein among Omani AIDS patients on combined antiretroviral therapy

Objective:To investigate the levels of zinc-α-2-glycoprotein(ZAG) among Omani AIDS patients receiving combined antiretroviral therapy(cART).Methods:A total of 80 Omani AIDS patients(45 males and 33 females),average age of 36 vears.who were receiving cART at the Saltan Qaboos University Hospital(SQUH).Muscat,Oman,were tested for the levels of ZAG.In addition,SO healthy blood donors(46 males and 34 females),average age of 26 years,attending the SOUH Blood Bank,were tested in parallel as a control group.Measurement of the ZAG levels was performed using a competitive enzyme—linked immunosorbent assay and in accordance with the manufacturer's instructions.Results:The ZAG levels were found to he significantly higher among AIDS patients compared to the healthy individuals(P=0.033).A total of 56(70%) of the AIDS patients were found to have higher levels of ZAG and 16(20%) AIDS patients were found to have high ZAG levels,which are significantly(P>0.031) associated with weight loss.Conclusions:ZAG levels are high among Omani AIDS patients on cART and this necessitales the measurement of ZAG on routine basis,as it is associated with weight loss.

Effect of TCM Combined with Chemotherapy on Immune Function and Quality of Life of Patients with Non-small Cell Lung Cancer inStage Ⅲ-Ⅳ

Objective: To observe and compare the effect of traditional Chinese medicine (TCM) combined with chemotherapy (CT) on immune function and quality of life (QOL)of patients with non-small cell lung cancer (NSCLC) in stage Ⅲ-Ⅳ. Methods: One hundred cases with stage Ⅲ-Ⅳ NSCLC were randomly divided into two groups. The treated group (n=50) received CT combined with TCM, and the control group received CT alone. The percentage of T lymphocyte subset in peripheral blood and the change of natural killer (NK) cell count were observed after treatment. The QOL and tolerance of CT were also compared between the two groups after treatment. Results: In the treated group, CD3 cell count, CD4 cell count, CD4/ CDg ratio and NK cell activity were higher than those in control group, while CD8 cell count in the treated group was lower than that in the control group (P<0.05), and QOL and tolerance of CT in the treated group were also better (P<0.05). Conclusion: TCM combined with CT could raise the patients' ability in tolerating CT in stage Ⅲ-ⅣNSCLC.

PCSS-SC通信下基于导频序列的主动式RAKE接收研究

RAKE接收是一种适合扩频通信和频率选择性衰落信道的抗多径技术,论文具体分析了传统RAKE接收技术应用在并行组合扩频散射(PCSS-SC)通信系统时存在的待优化问题,结合信道多径衰落分析和仿真模型,说明了该系统适用于RAKE接收设计要求。为改善散射信道存在的严重多径衰落,结合PCSS-SC系统并行体制特殊性,提出基于导频序列的主动式RAKE接收模型,同时采用选择性合并(SC)/等增益合并(EGC)混合的合并方式。仿真结果表明,该模型在改进传统RAKE接收技术的同时,可以适配在PCSS-SC通信环境,有效降低系统误码率。

Kinematics and dynamics analysis of a 3-7R parallel decoupling mechanism

One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three orthogonal distributional branch-chains, and all movable pairs are rotational joints. The movable platform of the mechanism has x, y, z translational decoupling directions. Furthermore, in order to verify the mechanism＇s decoupling characteristics, the mechanism＇s kinematics analysis is solved, and the mechanism＇s direct/inverse kinematics model, input/output velocities and accelerations are deduced, which confirm its decoupling movement characteristics. Finally, one kind of mechanism link decomposed-integrated approach is adopted, and the mechanism＇s dynamics model is completed with the Lagrange method, which also proves its decoupling force characteristics. All of these works provide significant theory for the further study of the mechanism＇s control strategy, design, path planning etc.

Kinematic Calibration and Forecast Error Compensation of a 2-DOF Planar Parallel Manipulator

Due to large workspace,heavy-duty and over-constrained mechanism,a small deformation is caused and the precision of the 2-DOF planar parallel manipulator is affected.The kinematic calibration cannot compensate the end-effector errors caused by the small deformation.This paper presents a method combined step kinematic calibration and linear forecast real-time error compensation in order to enhance the precision of a two degree-of-freedom(DOF) planar parallel manipulator of a hybrid machine tool.In the step kinematic calibration phase of the method,the end-effector errors caused by the errors of major constant geometrical parameters is compensated.The step kinematic calibration is based on the minimal linear combinations(MLCs) of the error parameters.All simple and feasible measurements in practice are given,and identification analysis of the set of the MLCs for each measurement is carried out.According to identification analysis results,both measurement costs and observability are considered,and a step calibration including step measurement,step identification and step error compensation is determined.The linear forecast real-time error compensation is used to compensate the end-effector errors caused by other parameters after the step kinematic calibration.Taking the advantages of the step kinematic calibration and the linear forecast real-time error compensation,a method for improving the precision of the 2-DOF planar parallel manipulator is developed.Experiment results show that the proposed method is robust and effective,so that the position errors are kept to the same order of the measurement noise.The presented method is attractive for the 2-DOF planar parallel manipulator and can be also applied to other parallel manipulators with fewer than six DOFs.

Combination Method for Parallel Computation in ODEs

In this paper, a 3rd order combination method with three processes and a 4th order combination method with five processes for solving ODEs are discussed. These methods are the Runge-Kutta method combined with a linear multistep method, which overcomes the defect of the 3rd order parallel Runge-Kutta method discussed in [1].

Coherent beam combining of hybrid phase control in master oscillator-power amplifier configuration

A novel scalable architecture for coherent beam combining with hybrid phase control involving passive phasing and active phasing in master oscillator-power amplifier configuration is presented. Wide-linewidth mutually injected passive phasing fibre laser arrays serve as master oscillators for the power amplifiers, and the active phasing using stochastic parallel gradient descent algorithm is induced. Wide-linewidth seed laser can suppress the stimulated Brillouin scattering effectively and improve the output power of the fibre laser amplifier, while hybrid phase control provides a robust way for in-phase mode coherent beam combining simultaneously. Experiment is performed by active phasing fibre laser amplifiers with passive phasing fibre ring laser array seed lasers. Power encircled in the main-lobe increases1.57 times and long-exposure fringe contrast is obtained to be 78% when the system evolves from passive phasing to hybrid phasing.

Realization of a tunable analog predistorter using parallel combination technique for laser driver applications

This paper describes a new approach for designing analog predistorters that can compensate for the nonlinear distortion of laser drivers in a radio-over-fiber （RoF） system. In contrast to previous works, this paper analyzes the transfer characteristics of CMOS transistors, by combining parallel currents of CMOS transistors in various W/L and negative bias voltages to realize the tunable analog predistortion function. The circuit is fabricated by a standard 0.18txm CMOS technology. The core circuit current consumption is only 15mA and the entire driver circuit works in a band-pass from 1 - 2.2GHz. Experimental results of two-tone tests have shown that with an analog predistortoer the IIP3 of the laser driver circuit has an improvement of 4.91 dB.

3-D Animation as Applied to the Solving of Coupling Relations in the 6-DOF Parallel Robot

How to solve the coupling relations in a 6 - DOF parallel robot quickly and accurately within the limits of realtime control is a critical problem. In traditional analytic method, the complicated mathemtical model must first be constructed and then solved by programming.Obviously, this method is not very practical. This paper,therefore, proposes a new way of approach with a new method using 3- D animation for the solving of coupling relations in the 6 - DOF parallel robot. This method is much simpler and its solving accuracy approaches that of the more complicated analytic method.

基于VIKOR的多网并行传输选网算法

海上异构无线网络通信场景下,针对单一无线网络难以承载大带宽业务的现实问题,提出了一种基于VIKOR的多网并行传输网络选择算法。该算法首先将多个网络的参数聚合,筛选可用网络组合;然后,结合网络属性的主客观权重和用户偏好权重得到网络属性的综合权重;最后,根据VIKOR方法对网络组合进行排序,选出最佳网络组合方案。仿真结果表明:该算法具有可行性,相较于传统算法,在舰船通信业务繁忙情况下选网综合性能更优。

大规模激光相干合成主动相位控制技术研究进展

大规模激光相干合成是突破单口径激光特性极限、获得超高峰值/平均功率、超大脉冲能量、超高空/谱亮度等极端特性激光的有效技术路径之一,而大规模激光相干合成的关键是主动相位控制。主动相位控制技术可以对各路光束相位进行主动控制,补偿相位噪声引起的相干特性退化、合成效率下降,获得高品质的合成激光。自相干合成技术提出以来,研究人员开发了多种主动相位控制方法用于相干合成相位校正,其中适用于大规模激光相干合成的主动相位控制方法也得到了飞速发展。系统梳理了大规模激光相干合成的主动相位控制方法,深入分析了不同方法的原理、特点、适用场景和扩展能力,介绍了不同方法取得的相干合成研究最新进展及标志性成果,报道了19通道闭环上升时间仅6μs的相干合成锁相控制突破性结果,最后总结和展望了主动相位控制方法的发展趋势。

激光相干合成系统中SPGD算法的分阶段自适应优化

为改善传统随机并行梯度下降(Stochastic Parallel Gradient Descent,SPGD)算法应用于大规模激光相干合成系统时收敛速度慢且易陷入局部最优解的情况,提出了一种分阶段自适应增益SPGD算法-Staged SPGD算法。该算法根据性能评价函数值,在不同收敛时期采用不同策略对增益系数进行自适应调整,同时引入含梯度更新因子的控制电压更新策略,在加快收敛速度的同时减少算法陷入局部极值的概率。实验结果表明:在19路激光相干合成系统中,与传统SPGD算法相比,Staged SPGD算法的收敛速度提升了36.84%,针对不同频率和幅度的相位噪声,算法也具有较优的收敛效果,且稳定性得到显著提升。此外,将Staged SPGD算法直接应用于37、61、91路相干合成系统时,Staged SPGD算法相比传统SPGD算法收敛速度分别提升了37.88%、40.85%和41.10%,提升效果随相干合成单元数增加而更加显著,表明该算法在收敛速度、稳定性和扩展性方面均具有一定优势,具备扩展到大规模相干合成系统的潜力。

机载光电平台主被动并联复合减振技术

针对制导跟踪系统中的机载光电平台在工作时受载机振动和气流扰动引起的宽频随机振动干扰,导致稳定精度下降、图像模糊、跟踪脱靶等问题,提出主被动并联复合减振控制技术。分别采用三环伺服控制和自抗扰位置控制策略,搭建基于音圈电机的单自由度机载光电平台主被动并联复合减振系统。仿真结果表明,主被动复合减振系统可有效降低振动信号对光电平台的影响,并且加入主动减振控制后的系统可以拓宽减振频宽,抑制低频振动信号且信号幅值可在被动减振基础上再次被有效衰减2个量级以上。

故障分离——一种基于FDA-SVDD的模式分类算法

为了克服多变量统计过程控制在故障分离上的缺陷,提出了一种新的故障分离方法。新方法由基于Fisher判别分析(FDA)的特征提取、Fisher线性分类和基于支持向量数据描述(SVDD)的非线性核空间模式分类等算法组成。构造了基于FDA-SVDD的串级和混联融合方式,并设计了基于SVDD的加权归一化半径模式判别准则。非等温连续搅拌槽(CSTR)过程仿真验证了混联融合比单纯的FDA分类算法和串级融合具有更优良的故障分离效果。

高职院校基于产教融合“分段并进式”专业实践课程体系的改革实践--以食品营养与检测专业为例

基于产教融合“分段并进式”专业实践课程体系的改革实践从人才培养方案、培养目标和课程标准的制定、校内实训基地的建立、专业实践课程体系的构建进行改革实践。在工作内容体验阶段对教学模式、教学方法、教学手段、考核方式进行了改革;在工学交替阶段和顶岗实习阶段对考核评价体系进行了改革。提出了专业实践课程体系改革的优势。