一种针对分离模块航天器系统的分层优化方法

针对分离模块航天器系统优化中存在计算量大、算法复杂度高的问题,提出了一种基于分层的分离模块航天器系统优化方法。该方法将系统优化问题分解为三个层次进行,顶层规划模块数和轨道高度,中间层优化组件配置,底层优化运载发射方案。其中顶层嵌套调用中间层,中间层嵌套调用底层,底层直接计算求解最优运载发射方案,避免了直接基于分离模块航天器全寿命周期仿真来优化运载发射方案。应用该方法对虚拟对地遥感分离模块航天器进行优化,结果表明,优化过程简单,计算量小,算法复杂度低,优化效果显著。

模块组配型条码编码容量研究

阐述了模块组配型条码的概念及其最大编码容量的计算方法.采用组合数学中典型的 型分配问题的求解方法,得到求取分配数的实用递推公式,从而提出针对(n,k)码的兼容最大编码容量的小量模块编码容量计算方法.基于对模块数的选择,对几种模块组配型国际标准条码编码字符集的设计准则进行了讨论,验证了计算方法的正确性.

基于双载波调制策略的模块化多电平矩阵变换器的优化电平方法

模块化多电平矩阵变换器(modularmultilevelmatrixconverter,MMMC)具备模块化的优点,能实现三相AC-AC的变换,且可用于高电压大功率的场合。但传统的载波移相调制策略在MMMC的模块数为偶数时,会导致桥臂上两两H桥子模块的输出电压发生100%的重合,从而致使桥臂上H桥子模块不能被高效使用。另一方面,桥臂上H桥子模块总输出电平数也会因此锐减,使得MMMC的工作效率低下。为了解决上述问题,提出一种新型的调制策略(即双载波调制策略)能够解决此问题且能大大提高MMMC的输出效果。通过理论分析、推导和在MATLAB/Simulink仿真平台上进行两种调制策略的仿真对比,验证了在MMMC的模块数为偶数时,在同等条件下,采用新型调制策略的输出效果优于采用传统调制策略的输出效果,且新型调制策略仅需传统调制策略一半的模块数就能达到与传统的调制策略一样的效果。因此新型的调制策略具有更高的经济性和应用价值。

模块化多电平柔性直流输电系统的直流侧启动方法研究

模块化多电平换流器的启动是系统正常运行的前提和基础,也是柔性直流输电系统运行过程中的重要环节。换流器交流侧为无源网络或待启动的有源网络时,启动过程需要增加辅助电源,增加成本和工作量。提出一种直流侧充电启动方法,通过不控整流预充电后子模块数递减方法解锁使子模块电容电压达到预先设定值,无需增加辅助电源,能有效限制充电过程中的电压和电流冲击。在PSCAD/EMTDC中搭建两端柔性直流输电系统模型,验证了该方法的可行性和有效性。

基于LCC和FHMMC的混合型直流输电系统

现有混合直流系统中,存在送端交流系统故障时电压严重跌落导致直流系统功率中断的情况。为解决这一问题,提出了一种新型的混合直流输电系统,其整流站采用电网换相换流器(LCC),逆变站采用半桥和全桥子模块混合的混杂式模块化多电平换流器(FHMMC)。重点推导了FHMMC在满足直流故障清除、功率续传要求下其子模块个数的配置要求,给出了混合直流系统的控制特性。并从换流站级和阀级两个层次上,对FHMMC的控制策略进行了研究设计。采用PSCAD/EMTDC,从起动、送端交流故障和直流故障3方面对相应模型进行了仿真研究。结果表明,与现有混合直流系统相比,所提出的系统能够更好地维持交流故障下的功率续传,并具有直流故障自清除能力。

融合面积估算和多目标优化的硬件任务划分算法

针对可重构计算机系统配置次数(划分块数)的最小化问题,提出了一种融合面积估算和多目标优化的硬件任务划分算法。该算法每次划分均进行硬件资源面积的估算,并且通过充分考虑可重构资源的使用、一个数据流图所有划分块执行延迟总和、划分模块间边数等因素构造了新的探测函数prior_assigned(),该函数能够计算每个就绪节点的优先权值,新算法通过该值能动态调整就绪列表任务节点的调度次序。实验结果表明,与现有的层划分、簇划分、增强静态列表、多目标时域划分、簇层次敏感等5种划分算法相比,该算法能获得最少的模块数,并且随着可重构处理单元面积的增大,除层划分算法之外,其执行延迟的均值也是最小的。

基于模型预测方法的MMC环流抑制策略

为了抑制模块化多电平换流器(MMC)的相间环流,提出一种基于模型预测(MPC)方法的环流抑制策略.该方法在传统系统控制的基础上,结合最近电平逼近调制,通过检测环流方向,利用模型预测实现模块数的实时更新,从而达到定量抑制二倍频环流的目的.和传统环流抑制策略相比,该方法不必考虑环流频率特性,同时省去了复杂的参数设计,实现简单,更适用于MMC模块数较多的工程实际情况.在PSCAD中对上述控制策略进行了仿真验证,结果表明:所提策略可以定量抑制MMC相间环流,从而有效减少桥臂电流畸变和子模块电压波动.

Designing simultaneous multichannel receivers based on fast filter bank

A scheme to design a simultaneous multichannel receiver is proposed to process multichannel signals in parallel, which is achieved by exploiting the attractive characteristics of a fast filter bank（ FFB）, such as cascaded structure, high frequency selectivity and lowcomputational complexity. Based on the minimization of the objective function, quantified in terms of the total number of multiplications required, subject to prescribed allowable ripples in the passband and stopband, the impulse response coefficients of the prototype filter in each stage are obtained to meet the requirements of the overall specifications for each channel at the receiver side. Simulations and experimental results on the frequency modulation（ FM） broadcast mutlichannel signal receiving system with the FM range from88 to 108 MHz, built upon the proposed FFB structure, are performed to verify its performance. Those results indicate that the proposed scheme is efficient in FM audio indexing applications and has a lower computational complexity, which is approximately 66. 4% of the weighted overlap and add（ WOLA） filter banks based solution.

Categorical Database Generalization

This paper focuses on the issues of categorical database gen-eralization and emphasizes the roles ofsupporting data model, integrated datamodel, spatial analysis and semanticanalysis in database generalization.The framework contents of categoricaldatabase generalization transformationare defined. This paper presents an in-tegrated spatial supporting data struc-ture, a semantic supporting model andsimilarity model for the categorical da-tabase generalization. The concept oftransformation unit is proposed in generalization.

Design and development of real-time query platform for big data based on hadoop

This paper designs and develops a framework on a distributed computing platform for massive multi-source spatial data using a column-oriented database(HBase).This platform consists of four layers including ETL(extraction transformation loading) tier,data processing tier,data storage tier and data display tier,achieving long-term store,real-time analysis and inquiry for massive data.Finally,a real dataset cluster is simulated,which are made up of 39 nodes including 2 master nodes and 37 data nodes,and performing function tests of data importing module and real-time query module,and performance tests of HDFS's I/O,the MapReduce cluster,batch-loading and real-time query of massive data.The test results indicate that this platform achieves high performance in terms of response time and linear scalability.

Allowable Generalized Quantum Gates

In this paper, we give the most general duality gates, or generalized quantum gates in duality quantum computers. Here we show by explicit construction that a n-bit duality quantum computer with d slits can be simulated perfectly with an ordinary quantum computer with n qubits and one auxiliary qudit. Using this model, we give the most general form of duality gates which is of the form ∑i=0^d-1piUi,and the pi ＇s are complex numbers with module less or equal to 1 and constrained by｜∑iPi｜≤1.

Thermal Characteristics of Optoelectronic Modules with DIP and BGA Package

In order to meet the electrical and thermal performance requirements of current high performance optoelectronics, two package types with dual-in-line package(DIP) and ball grid array(BGA) for optoelectronics are modeled and thermally simulated, their thermal characterizations are compared and discussed by using the temperature contours and the simulated heating characterization curves in free air and forced air ambient. The results show that BGA has superior inside and outside total performances, and has the promising future in the highly integrated optoelectronics.

Geometrical Langlands Ramifications and Differential Operators Classification by Coherent D-Modules in Field Theory

Spaces of equivalence modulo a relation of congruence are constructed on field solutions to establish a theory of the universe that includes the theory QFT （Quantum Field theory）, the SUSY （Super-symmetry theory） and HST （heterotic string theory） using the sheaves correspondence of differential operators of the field equations and sheaves of coherent D - Modules [1]. The above mentioned correspondence use a Zuckerman functor that is a factor of the universal functor of derived sheaves of Harish-Chandra to the Langlands geometrical program in mirror symmetry [2, 3]. The obtained development includes complexes of D - modules of infinite dimension, generalizing for this way, the BRST-cohomology in this context. With it, the class of the integrable systems is extended in mathematical physics and the possibility of obtaining a general theory of integral transforms for the space - time （integral operator cohomology [4]）, and with it the measurement of many of their observables [5]. Also tends a bridge to complete a classification of the differential operators for the different field equations using on the base of Verma modules that are classification spaces of SO（l, n ＋ 1）, where elements of the Lie algebra al（1, n ＋ 1）, are differential operators, of the equations in mathematical physics [1]. The cosmological problem that exists is to reduce the number of field equations that are resoluble under the same gauge field （Verma modules） and to extend the gauge solutions to other fields using the topological groups symmetries that define their interactions. This extension can be given by a global Langlands correspondence between the Hecke sheaves category on an adequate moduli stack and the holomorphic L G - bundles category with a special connection （Deligne connection）. The corresponding D - modules may be viewed as sheaves of conformal blocks （or co-invariants） （images under a version of the Penrose transform [1, 6]） naturally arising in the framework of conformal field theory.

Improved CFD modeling of full dissolution of alumina particles in aluminum electrolysis cells considering agglomerate formation

The full alumina dissolution process in aluminum electrolysis cells was investigated using an improved computational fluid dynamics(CFD)model based on the previous researches by consideration of agglomerate formation.The results show that the total mass of alumina agglomerate and its maximum size are mainly dependent on the feeding amount and increase with increasing it.Higher superheat can effectively inhibit the agglomerate formation and thus promote the full alumina dissolution behavior.The full alumina dissolution process mainly includes a fast stage and a slow stage,with an average dissolution rate of 17.24 kg/min and 1.53 kg/min,respectively.About 50%(mass percentage)of the total alumina particles,almost all of which are the well-dispersed alumina fine grains,dissolve within the fast dissolution stage of about 10 s.The maximum values of the average dissolution rate and final percentage of the cumulative dissolved alumina mass are obtained with a feeding amount of 1.8 kg for a superheat of 12℃.The formation of the alumina agglomerates and slow dissolution characteristics play a dominant role in the full dissolution of alumina particles.

Design and Implementation of Data Acquisition System based on Linux Platform

This paper introduces the hardware structure and software design of data acquisition system based on embedded Linux. In order to improve the real-time response performance and the ability of multi task for system, using ARM9 microprocessor technology in hardware, and transplant the Linux operating system, and the system reliability and scalability can be improved. The design makes full use of the characteristics of embedded Linux. The system software module have data acquisition module, data processing module, data communication module and data diagnostic module. The embedded Linux operating system is transplant into data acquisition system, that can accelerate the development of the system and convenient to future expansion functions, improve the observation data timeliness and accuracy, and can realize automation observation.

Design and Implementation of English Teaching Management System Based on Web

In order to improve the intelligence of the English teaching management, so as to improve the English teaching resource scheduling and sharing ability, a design method of teaching management system is proposed based on Web. The system adopts Web network architecture design, mainly it is divided into MUC main control module, database module, data management module and man-machine interaction module, Network management and online scheduling of English teaching resources are obtained based on C/S framework, data exchange of English teaching resources is realized on client side and server side, the control component of the English teaching resource distribution database uses MBM29LV400BC as the logic decoding controller. The intelligent algorithm is used to analyze the big data to realize the scheduling and access control of the English teaching management system resources. The test results show that the design of the English teaching management system has good resource scheduling and database construction ability, and the overall intelligence of the system is better.

Collision Analysis of the Spar Upper Module Docking

In order to assess the possible collision effect, a numerical simulation for the upper module and spar platlbrm docking at the speed of 0.2 m/s was conducted by using the software ANSYS/LS-DYNA, and the time history of the collision force, energy absorption and structural defonamtion during the collision was described. The purpose was to ensure that the platlbrm was safely put into operation. Furthermore, this paper analyzes different initial velocities and angles on the Von Mises stress and collision resultant force during the docking collision. The results of this paper showed that the docking could be conducted with higher security. The data in this paper can provide useful references for the determination of the upper module＇s offshore hoisting scheme and practical construction by contrasting the numerical simulation results of the parameters on the docking collision.

Mathematic Model of Unsteady Penetration Mass Transfer in Randomly Packed Hollow Fiber Membrane Module

Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data.

Design of Parallel Electrical Resistance Tomography System for Measuring Multiphase Flow

ERT(electrical resistance tomography) is effective method for visualization of multiphase flows,offering some advantages of rapid response and low cost,so as to explore the transient hydrodynamics.Aiming at this target,a fully programmable and reconfigurable FPGA(field programmable gate array)-based Compact PCI(peripheral component interconnect) bus linked sixteen-channel ERT system has been presented.The data acquisition system is carefully designed with function modules of signal generator module;Compact PCI transmission module and data processing module(including data sampling,filtering and demodulating).The processing module incorporates a powerful FPGA with Compact PCI bus for communication,and the measurement process management is conducted in FPGA.Image reconstruction algorithms with different speed and accuracy are also coded for this system.The system has been demonstrated in real time(1400 frames per second for 50 kHz excitation) with signal-noise-ratio above 62 dB and repeatability error below 0.7%.Static experiments have been conducted and the images manifested good resolution relative to the actual object distribution.The parallel ERT system has provided alternative experimental platform for the multiphase flow measurements by the dynamic experiments in terms of concentration and velocity.

Research on marketing module and competitive strategy of E-Business Based on the VIP Website

E-Business now is developing fast in China and the development of E-Business strategy is crucial as the right strategy can make the E-Business select the correct direction and get a better development. In this paper, combined with SWOT parameters module, we will make a thorough research on the strategies used by Vip.eom from different angles. After this research, we will have a good understanding of strategies used by VIP website and learn to make better decisions in the e-business world.