微型靶件装配中自动对焦方法的研究

惯性约束激光聚变(ICF)实验对微靶的装配精度要求越来越高,基于机器视觉的在线监测系统是微靶零件测量的主要手段。精确的光学聚焦是进行稳定、高精度测量的前提。提出了一种基于三维精密位移平台的主动对焦方法。通过实验选取了合适的清晰度评价函数。采用大步长找区域,小步长找点的搜索策略,实现了系统的快速精确对焦,调焦精度可优于10μm,总体调焦时间约为30 s。克服了手动调焦时间长,不能保证成像完全清晰的问题。     

混合模型下FMM算法中近程计算的优化研究

为提高计算多体问题的效率,通过分析多体问题的典型算法FMM(fast multiple method)的计算特点,提出运用CPU和加速部件FPGA构成混合部件计算其近程作用的方案。重点研究混合计算模型上的近程计算特性和优化策略,从计算、通信和存储多方面分析近程计算,提出分层按块的数据准备策略,及在该策略中修改FMM空间编码方式,使近程计算更好地适应于混合模型,从而提高整个FMM算法的执行效率。实验结果表明了该数据准备策略和采用的空间编码方式的可行性和高效性。     

A fast hybrid computer vision technique for real-time embedded bus passenger flow calculation through camera

Bus passenger flow calculation system is a critical part of the smart public transportation framework. Bus passenger flow information can help to make data statistics report of the passenger at a bus station which can be used by public transport operator to evaluate the quality of the transportation. Statistics report of crowded passengers in the bus station help managers to understand the bus transit operations, can provide the database for the intelligent transportation scheduling, help to provide more and better services for passengers, overall data statistics of passengers has important practical significance to improve public transport environment. This paper presents a passenger counting algorithm based on hybrid machine learning approach. In the first step, an advanced method is used to extract the Histogram of oriented gradients (HOG) feature of passenger’s heads. Classification of head features is done by using support vector machine (SVM) as a classifier for the liner model. Heads are detected successfully after performing all steps. In next step Kanade-Lucas-Tomasi (KLT) is used to reality head tracking, the multiple target tracking is achieved and the head motion trajectory of passenger target is captured stably. At last, the trajectory is analyzed and the automatic counting of bus passenger flow is realized. In the last step, the proposed algorithm is move to embedded system for practical implementation. In this paper, the algorithm intends to use ADSP-BF609 embedded platform for transplantation. The experimental results demonstrate that the statistical accuracy of the proposed algorithm is enhanced successfully; especially during the daytime with the good illustration, the effective counting of the passenger flow is achieved and the inward and outward passenger counting can be realized. In this paper three feature extraction models are used namely local binary patterns, histograms of oriented gradients and binarized statistical image in order to get accurate features. Furthermore, three common classification techniques including naïve bayes classifier, boosted tress and support vector machines are used for fine classification of extracted vectors obtained from different features extractors model. 94.50% accuracy is achieved when support vector machine (SVM) classifies the features extracted using Histogram of oriented gradients (HOG). SVM surpasses the accuracy obtained by Boosted tree namely 81.30% using Histogram of oriented gradients (HOG) features.

     

基于6DOF模型及动网格的动静压轴承刚度阻尼数值计算

针对传统雷诺方程求解三维油膜流场特性的局限性,提出基于6DOF模型及动网格的动静压轴承刚度阻尼计算方法.以具有典型结构形式的液体动静压轴承为例,通过加载6DOF自定义程序,采用非线性迭代方法计算外载荷作用下轴心轨迹的瞬态变化过程,得到轴颈在外载荷作用下的静平衡位置;通过嵌入UDF宏程序以动网格更新方法实现对轴颈在静平衡位置的扰动,求解Navier-Stokes方程得到轴颈扰动前后位置变化后的瞬态油膜力,利用差分法求得动静压轴承油膜刚度和阻尼,并分析了不同转速下轴承刚度和阻尼的变化规律.     

面向多维混合型数据分布的混合多维直方图初探

现实世界中,多维数据分布常常不是单一一种类型,而是在不同的数据区域中呈现不同类型的数据分布.提出了一种面向多维混合型数据分布的混合多维直方图COCA*-Hist方法.这种方法在给定的空间预算下,根据数据分布空间不同的区域中的数据分布类型,可以包含多种不同类型的直方桶,从总体上提高直方图的准确性.由于需要对创建多维直方图的树结构进行二次遍历,以识别不同类型的数据分布区域并进行空间预算的重分配,COCA*-Hist时间效率略低于MHist算法,但对因此获得的准确性的提高和面对不同数据分布类型的通用性来说,是可以接受的.     

Using a checklist-based electronic calculation aid and contextual cues to assist medication dose calculation and calculation resumption after interruptions

ObjectivesTo examine whether (1) the use of a checklist-based electronic calculation aid enhanced medication dose calculation and reduced the negative effects of interruptions on calculation, and (2) the use of contextual cues facilitated the resumption of calculation after an interruption.MethodsSixty students in healthcare majors participated in two computer-based laboratory experiments. Experiment 1 examined the effects of the calculation aid and interruptions on calculation error rate, calculation completion time, and perception outcomes. Experiment 2 assessed the effects of contextual cues on resumption error rate, calculation error rate, calculation completion time, and perception outcomes.ResultsIn Experiment 1, calculation error rates were lower for participants who received the calculation aid versus those who did not, and for uninterrupted calculations versus interrupted calculations, although the differences were not statistically significant.The participants spent significantly less time completing the calculation task with the use of the calculation aid than without the use of the calculation aid, and in the case without interruptions than in the case with interruptions. In Experiment 2, the use of contextual cues associated with previous actions significantly reduced the resumption error rate and the completion time of the medication dose calculation. Both experiments showed that the use of the calculation aid and contextual cues was associated with positive attitudes toward the aid and cues, reduced mental effort, and/or higher confidence in task performance.ConclusionsThe use of the checklist-based electronic calculation aid and contextual cues facilitated medication dose calculation and resumption after interruptions and thus has the potential to improve medication safety and work efficiency in healthcare.     

Numerical calculation of electromagnetic forces

In this paper models for field determination in electromagnetic devices in order to calculate forces are discussed. Proposed models accounting for saturation and movement with high accuracy field values needed for force calculation are also given. Finite elements are used in the saturated parts coupled with analytical solution or boundary integral in the air-gaps.Numerical applications are done on electromagnets and results are given at the end of the paper.     

Computer-aided calculation of accident costs

Accurate data about accident costs motivate top managers to improve safety in production. The problem has been, however, to specify costs reliably and easily. This article presents the computer-aided module for calculating accident costs in the TATU-Safety Information System developed by the Finnish Institute of Occupational Health. The module computes the direct costs and company-controlled total costs of accidents. The calculation is based on the accident consequence tree (ACT) method. The software provides information about accident costs to motivate accident prevention. The authors explain the system design of the software and its use in cost calculation. © 1997 John Wiley & Sons, Inc.     

Sequential calculation of the median

Data collection during discrete event digital simulation may involve sampling either continuous or discrete variables. The most commonly used data collection techniques are sequential in the sense that they do not require storage of each observation. It is this moderation of storage requirements that makes such data collection techniques useful in the output analysis of large scale simulations and in the experimental evaluation of random number generators. For some distributions the same median is superior to the sample mean as an estimator of the population mean. When the sample median is desired it is common to store every observation. These observations are then sorted in order to find the central value. This paper describes a sequential technique that permits the median to be calculated without storing all observations. For example, if 100,000 samples are to be taken, selective storage of 440 observations will permit an exact calculation of the sample median with probability 0.98. If the method fails a warning is provided. Central processor unit (CPU) running time for sequential calculation of the median is competitive with the best sorting algorithms.     

激光打印机硒鼓的再生利用技术

激光打印机硒鼓不仅相对打印成本过高,同时使用过的旧硒鼓还是永远不可分解的高科技垃圾。于是,通过循环再利用硒鼓的再生利用技术便成为减少环境污染和降低打印成本的有效途径。对就硒鼓的再生利用技术的关键技术和创新点进行了详细阐述,具有较强的实用性和可操作性。     

The calculation of singular coefficients

We consider in this paper the calculation of the ‘singular coefficients’ associated with the solution of an elliptic partial differential equation near a singular point; a re-entrant corner, or a crack tip, etc. These are the coefficients in the relevant singular expansion of the solution near the point of singularity; they often have physical relevance, and it is of interest to be able to calculate them accurately. We consider the problem in the context of the global element method; this is a variable-order finite element method designed to be capable of producing highly accurate solutions for singular problems, even in the neighbourhood of the singularity. If the values of the singular coefficients are needed, these must be extracted from the computed solution; we show in this paper that a suitably defined least-squares fitting procedure allows the calculation of values for the leading singular coefficients which are as accurate as the underlying solution.     

分子计算理论方法及在化工计算中的应用

论述了量子力学中从头计算、半经验和密度泛函方法及分子力学的基础理论,概述了常用的MD、MC分子模拟方法,总结了多种应用软件的主要功能,并结合实例对HyperChem．7软件的功能进行了具体的说明。     

Distance calculation on strings

A monoid of strings (words) over a finite alphabet is considered. The notion of distance on strings is important in the problem of inductive learning related to artificial intelligence, in cryptography, and in some other fields of mathematics. The distance is defined as a minimum length of the transformation path that transforms one string into another. One example is the Levenstein distance, with the transformations being insertions, deletions, and substitutions of letters. A quadratic algorithm for calculating this distance is known to exist. In this paper, a more general case—insertion and deletion of words of arbitrary length—is considered. For this case, the problem of distance calculation turns out to be unsolvable. The basic results of this work are the formulation of the condition of computability of distance and the algorithm for distance calculation, which is polynomial in string length.