生物序列比对算法研究现状与展望

序列比对是生物信息学研究的一个基本方法,寻求更快更灵敏的序列比对算法一直是生物信息学研究的热点.本文给出了生物序列比对问题的定义,综述了目前常用的各类比对算法,并对每一类算法的优缺点以及应用范围进行了分析,最后指出序列比对算法目前存在的问题以及未来的发展方向.     

鲁棒UKF滤波算法在SINS初始对准中的应用

针对系统存在不确定性扰动时传统UKF滤波算法的滤波精度和鲁棒性均下降的问题,提出了一种基于H∞范数的鲁棒UKF滤波算法.该算法在Krein空间内对简化UKF滤波算法进行改进,增加了一个鲁棒环节.鲁棒环节通过引入给定正常数调整滤波增益从而提高滤波算法的鲁棒性能.在SINS大方位失准角初始对准中对简化UKF滤波算法和鲁棒U...     

基于均值移动重要性采样的粒子滤波人脸跟踪算法

针对condensation目标跟踪算法中用先验转移概率作建议分布函数时没有充分考虑最新观测信息的缺点,提出了一种基于均值移动重要性采样的粒子滤波人脸跟踪算法.算法首先利用均值移动跟踪器粗略定位人脸目标,然后再用此跟踪结果去构造建议分布函数进行粒子传播.由于通过该方法所构造的建议分布函数中包含了最新的观测信息,所以它可以使大多数粒子点都能分布在真实状态区域周围,进而提高了粒子传播的准确性.人脸跟踪结果表明,该算法的跟踪性能明显优于标准condensation方法.     

Implementation of autofocus in alignment system for layered imprint fabrication

Autofocus method based on the analysis of image content information is investigated to reduce the alignment error resulting from mark positioning uncertainty due to defocus in microstructure layered fabrication process based on multilevel imprint lithography, The applicability of several autofocus functions to the alignment mark images is evaluated concerning their uniformity, sharpness near peak, reliability and measure computation efficiency and the most suitable one based on power spectrum in frequency domain (PSFD) is adopted. To solve the problem of too much computation amount needed in PSFD algorithm, the strategy of interested region detection and effective image reconstruction is proposed and the algorithm efficiency is improved. The test results show that the computation time is reduced from 0.316 s to 0.023 s under the same conditions while the other merits of the function are preserved, which indicates that the modified algorithm can meet the mark image autofocusing require-ments in response time, accuracy and robustness. The alignment error due to defocus which is about 0.5 μm indi-cated by experimental results can be reduced or eliminated by the autofocusing implementation.     

A novel posture alignment system for aircraft wing assembly

A novel 6-degree of freedom （DOF） posture alignment system, based on 3-DOF positioners, is presented for the assembly of aircraft wings. Each positioner is connected with the wing through a rotational and adsorptive half-ball shaped end-effector, and the positioners together with the wing are considered as a 3-PPPS （P denotes a prismatic joint and S denotes a spherical joint） redundantly actuated parallel mechanism. The kinematic model of this system is established and a trajectory planning method is introduced. A complete analysis of inverse dynamics is carried out with the Newton-Euler algorithm, which is used to find the desired actuating torque in the design and path planning phase. Simulation analysis of the displacement and actuating torque of each joint of the positioners based on inverse kinematics and dynamics is conducted, and the results show that the system is feasible for the posture alignment of aircraft wings.     

Adaptive sampling for mesh spectrum editing

INTRODUCTION Free-form surface editing plays an importan part in geometric modeling, such as Free-Form De- formation (FFD), level of detail editing. Users need to be careful to avoid artifacts in the result surface. In this paper, we present a new mesh editing technique based on geometry signal wavelet analysis. It indi- rectly modifies vertex positions in spatial domain by the simple geometry proxy that is simplified from the original mesh, and performs filtering and enhance- ment in f…     

通用组合式教育机器人动力学模型及其快速仿真算法(英文)

为实现具有开放结构的组合式教育机器人自动建模与动态仿真,建立了教育机器人的动力学模型及其仿真算法.首先,将教育机器人抽象为多体系统,利用牛顿一欧拉法建立其通用的动力学模型,并结合教育机器人的结构特点,以构件绑定方法对机器人模型进行了简化.其次,基于稀疏矩阵计算技术,对计算机仿真中常用的增广动力学求解算法和直接投影修正算法进行改进,以此作为教育机器人的仿真算法,提高仿真速度和精度.最后,通过一个算例验证了模型和改进算法的有效性.该研究为实现教育机器人仿真平台奠定了动力学基础.     

基于近似动态规划的相邻两交叉口信号协调控制算法

为减少路网机动车尾气排放,建立了基于近似动态规划的相邻两交叉口信号协调控制算法.以捷达车作为试验车辆,在长春市长春大街进行实车实验,采集了完全停车以及匀速行驶2种状态下的机动车排放因子;以进口道排队长度、信号灯色作为系统状态的表达变量,以绿灯切换方案作为决策变量集,采用近似动态规划中的基函数方法,建立了规划时间窗内优化...     

Vector sampling theorem for wavelet subspaces

The vector sampling theorem has been investigated and widely used by multi-channel deconvolution, multi-source separation and multi-input multi-output （MIh40） systems. Commonly, for most of the results on MIMO systems, the input signals are supposed to be band-limited. In this paper, we study the vector sampling theorem for the wavelet subspaces with reproducing kernel. The case of uniform sampling is discussed, and the necessary and sufficient conditions for reconstruction are given. Examples axe also presented.     

SARS相关冠状病毒与其他已知冠状病毒的膜蛋白的多序列联配

1　Introduction　SARSisthefirstnewlyidentifiedseriousinfectiousdiseasethathumanbeingisfacingatthebeginningofthe 2 1stcentury .Ithasbeen primarilyrecognizedthatavariantofvirusfromthecoronavirusfamilymightbethecandidatepathogenofSARS ,asreportedbyWHO (WorldHealthOrganization)onApril 2 9,2 0 0 3(http ://www .who .int/csr/sarscountry/en) .　Coronaviruseswerefirstisolatedfromchickensin1937.Therearenowapproximately 15speciesinthisfamily.Coronavirusparticlesareirregularlyshaped ,roundabout 6 0 …     

Assessment thresholds for academic staff: constructive alignment and differentiation of standards

Abstract

This qualitative study utilized episodic narrative interviews to investigate assessment thresholds involved in the development of assessment literacy. The goal of the study was to inform efforts toward quality improvements in higher education. Thirty-five academic staff from universities in Australia, Canada and Sweden shared stories of significant changes they made to their assessment practice. Thematic analysis found troublesome aspects to include instructor expectations, lack of consistency, differentiation of performance, student expectations, time constraints/workload, logistical/technological constraints and assessment policy. A belief in meaningful learning, embracing constraints and the desire to meet the needs of students, added to other enablers for assessment change, such as resources, support and strategic use of technology. Findings suggested assessment thresholds of constructive alignment and differentiation of standards. Reflection, collaboration and professional development were found to support the integration of assessment knowledge and build conceptual understanding of assessment thresholds. Authors recommend that higher education institutions provide academic staff with a foundation of conceptual understanding of these key areas to promote moves toward quality assessment practices.     

压缩采样中基于离散时间马尔科夫链的动态控制机制

针对信号稀疏度在大多数情况下时变且未知的问题,提出了一种实时信号稀疏度预测及最优采样速率确定机制.利用离散时间马尔科夫链对信号稀疏度进行建模,分析信号稀疏度各状态之间变化的规律,根据当前状态预测下一个采样周期内信号的稀疏度状态及概率.此外,基于预测结果,综合考虑采样过程中的能量消耗和信号重构的精确度,以最大化预期收益为...     

Brief Introduction to Self—Adapting Hidden Markov Model Program for multiple Sequences Alignment

In this letter,we briefly describe a program of self-adapting hidden Markov model(SA-HMM) and its application in multiple sequences alignment.Program consistes of two stage optimisation algorithm.     

Alternative Monte Carlo Approach for General Global Illumination

Ithasbeenwellknownthatglobalilluminationsimu latesthelighttransportamongallthesurfacesandthelightsourcesinavirtualsceneconsideringdiffusereflection/refrac tionandspecularreflection/refraction .Duetosimplicity,generalityanddimensionalindependence,MonteCarlomethodorrandomwalkmethodisoneofthemostimportantmethodsforsolvingthedifficultglobalillumination .Inpartic ular,MonteCarloisthelastresortwhenallotheranalyticalornumericalmethodsfail[1 ] .　　Lighttransportormultiplelightinteractionsamongthesu…     

一种基于采样的并行电力负荷数据流划分方法

为了解决电力工业中并行数据流范围聚集的连续查询问题,提出一种新颖的数据流划分方法.首先构造了一个适用于数据流处理的扩展蓄水池抽样算法,根据流值变化率引入跳跃因子反应负荷数据的变化情况,实现数据流的自适应并行采样.然后为了实现数据流量的平均划分,基于近似技术提出2种适应不同情况的生成等深柱状图的算法:增量更新的启发式方法和周期性更新的快捷方法,从而在采样的基础上生成近似划分向量.通过在实际数据集上对算法性能测试,证明文中提出的数据流划分方法高效实用,适合于高速时变数据流的处理.     

基于核密度估计多样性采集的背景建模算法

1IntroductionBackground subtraction methods are extensively ex-ploited for moving object detection in videos in manyapplications ,such as traffic monitoring[1],human mo-tion capture[2]and video surveillance[3]. The centralidea behind such methods is to segment foreground ini mage sequences taken from a fixed camera by com-paring each newframe to a model of the scene back-ground . Therefore , correctly and efficiently modelingand updating the background model is one of the mostchallenging aspec…     

创建neighbor-joining进化树的快速算法

为了改善Saitou和Nei提出的neighbor-joining进化树算法(SN)及Studier和Keppler的改进算法(SK),降低计算的时间复杂度,设计了一种快速算法.该算法涉及3种技术第一,引入一个线性数组A[N],用于存储距离矩阵每一行的值,以减少许多重复计算;第二,A[i]的值在算法开始时全部计算,在迭代步中间只进行更新3个变化的值;第三,设计了一个紧凑的公式用于计算OTUs之间的边长,并对该公式进行了证明.实验结果表明随着节点数的增多,该算法比SN算法快几十倍到上百倍,比SK算法快2倍以上;在一台桌面计算机上,该算法能在3min左右创建具有2000个节点的进化树.以空间换时间,减少最内层循环的计算量是设计多重循环算法的基本思路.     

动态规划法解算多阶段决策问题研究

多阶段决策问题是程序设计领域的一类经典难题,采用传统的程序设计方法必然使得程序运行需要大量的时间和空间资源,而效率低下。应用动态规划法很好地解决了多阶段决策问题,并应用C＋＋STL技术,实现了该问题的程序设计,并大大提高了程序运行的时间和空间效率。     

Analogical encoding with and without instructions for case comparison of scientific phenomena

The study aimed to extend current research on conditions that better support analogical encoding through mutual alignment. We focused on two variables that have not been examined independently in previous studies: the joint presentations of two cases of a scientific phenomenon and the explicit instructions for comparison. One hundred and sixty-five 5th graders and one hundred and sixty-eight 7th graders were presented with two pairs of scenarios, one about heat flow and the other about the state change of matter. Participants were randomly assigned to three conditions: sequential presentation of scenarios, joint presentation of scenarios and joint presentation of scenarios with explicit instructions to compare analogically. Results show that for both pairs of scenarios, analogical encoding was promoted more in the condition of joint presentation of scenarios with instructions for comparison. In addition, 7th graders benefited more from this condition than 5th graders.     

碳管法燃煤烟气汞浓度取样装置研制

自主研制了包括内置吸附剂和两段式碳吸附管在内的整套新型碳管法烟气汞浓度取样装置,以期实现燃煤烟气中颗粒汞和气相总汞浓度的精确测量．在6 kW 燃煤循环流化床装置上同时采用碳管法与安大略标准法（OHM）进行烟气中汞浓度取样．结果表明,碳管法所得汞平衡率均处于95．47％～104．72％之间．不同工况下碳吸附管第2段穿透率始终低于2％,且与相同工况下 OHM 测试结果的相对偏差在15．96％～17．56％之间,均小于20％．结果表明,所研制的碳吸附管干法烟气汞浓度取样装置符合美国 EPA 质量保证和质量控制（QA／QC）标准,可应用于实际燃煤烟气汞浓度的取样测试．