一种基于光电经纬仪的数据预测跟踪技术

针对光电经纬仪上的跟踪器,提出了一种基于合成角数据的预测跟踪技术.利用目标的前几帧脱靶量和对应的经纬仪角度信息计算合成角,再以前几帧合成角数据为依据,利用线性动态模型推导出下一帧的合成角信息,计算出目标在图像中的位置,从而实现了对目标的预测跟踪.实验证明,该方法可以实现预测跟踪,减小处理区域,提高跟踪器的处理速度,有效地避免波门外虚假目标的干扰.     

舰载光电经纬仪预测跟踪技术研究

研究了舰载光电跟踪设备的稳定跟踪技术,提出了一种基于机动平台预测跟踪方案.利用坐标转换将前几帧合成角数据转换到大地坐标系,并利用合成角轨迹预测当前帧合成角数据,然后将预测结果转换到甲板坐标系,实现了机动平台的稳定跟踪;给出了该预测结果与在甲板坐标系直接预测结果的比对,证明该预测技术更为精确,有利于实现机动平台的稳定跟踪.     

Continuously balanced pulse-DC ioniser to minimise the offset voltage

In our previous work, the AC type of ionisers was employed to demonstrate a prospective theory obtained by numerical simulations in which continuously emitting quasi-neutralised positive and negative ions from corona ionisers can transport ions effectively to a charged object and yield zero offset voltage. In this paper, we show that this can also be applied to pulse-DC ionisers, resulting in significant improvements in the offset voltage as well as charge-decay times. In addition, we present an implementation method with an electronic circuit design to create such an ion emission from a pulse-DC ioniser.     

An improvement on AC ionisers to minimise the offset voltage

We present an experimental demonstration of a prospective idea obtained from 2-D electrohydrodynamic simulations in which continuously emitting balanced positive and negative ions from corona ionisers can yield zero offset voltage.     

氧碘化学激光中的增益光导效应

 发现和分析了氧碘化学激光中的增益光导效应。碘注入的不均匀等导致增益在该方向的不均匀。采用预混模型和Fabry Perot腔模型，推导了碘不均匀分布情况下的单重态氧的产额和激光束横向分布的解析表达式。计算结果表明，由于增益光导效应，引起激光横向分布的变化，可导致光束在碘注入方向的倾斜，以及输出功率的下降。     

Optimizing a constrained convex polygonal annulus

In this paper we give solutions to several constrained polygon annulus placement problems for offset and scaled polygons, providing new efficient primitive operations for computational metrology and dimensional tolerancing. Given a convex polygon P and a planar point set S, the goal is to find the thinnest annulus region of P containing S. Depending on the application, there are several ways this problem can be constrained. In the variants that we address the size of the polygon defining the inner (respectively, outer) boundary of the annulus is fixed, and the annulus is minimized by minimizing (respectively, maximizing) the outer (respectively, inner) boundary. We also provide solutions to a related known problem: finding the smallest homothetic copy of a polygon containing a set of points. For all of these problems, we solve for the cases where smallest and largest are defined by either the offsetting or scaling of a polygon. We also provide some experimental results from implementations of several competing approaches to a primitive operation important to all the above variants: finding the intersection of n copies of a convex polygon.     

Obtaining the Maximum Likelihood Estimates in Incomplete R × C Contingency Tables Using a Poisson Generalized Linear Model

Abstract

This article describes estimation of the cell probabilities in an R × C contingency table with ignorable missing data. Popular methods for maximizing the incomplete data likelihood are the EM-algorithm and the Newton-Raphson algorithm. Both of these methods require some modification of existing statistical software to get the MLEs of the cell probabilities as well as the variance estimates. We make the connection between the multinomial and Poisson likelihoods to show that the MLEs can be obtained in any generalized linear models program without additional programming or iteration loops.     

Two-dimensional offsets and medial axis transform

We present a mathematical theory of the two-dimensional offset curves from the viewpoint of medial axis transform. We explore the local geometry of the offset curve in relation with the medial axis transform, culminating in the classification of points on the offset curve. We then study the domain decomposition from the viewpoint of offsets, and in particular introduce the concept of monotonic fundamental domain as a device for detecting the correct topology of offsets as well as for stable numerical computation. The monotonic fundamental domains are joined by peaks or valleys of the medial axis transform, or by what we call the critical horizonal section whose algebro-geometric properties are rigorously treated as well. First author holds joint appointment in the Research Institute of Mathematics, Seoul National University.     

Experimental distribution of phases and pressure drop in a two-phase offset strip fin type compact heat exchanger

Uniform distribution of fluids is crucial to obtain high performance in compact heat exchangers. Maldistribution has been studied by many authors, especially for parallel channels heat exchangers. But theoretical models and experimental studies for predicting flow maldistribution in offset strip fins exchangers are scarce. Offset strip fins, besides their higher thermal hydraulic performances, favour lateral distribution due to their geometry. In this work, an experimental investigation has been carried out for this type of heat exchanger. The experimental set-up consists in a flat vertical compact heat exchanger (1 m × 1 m area and 7.13 mm thickness) equipped with offset strip fins with a hydraulic diameter of 1.397 mm. Air and water are the working fluids. The flow rates of each phase in seven zones regularly distributed at the outlet have been measured as well as the pressures at the inlet, the outlet and two intermediate positions. These measurements were completed with visualisations using a high-speed camera.     

Fundamental Frequency Change During Offset and Onset of Voicing in Individuals with Parkinson Disease

SUMMARY: After years of treatment with the medication levodopa, most individuals with Parkinson disease (PD) experience fluctuations in response to their medications. Although relatively consistent perceptual voice improvements have been documented to correspond with these fluctuations, consistent quantitative data to support this finding are lacking. This mismatch may have occurred because most of this phonation research has centered on long-term phonatory measures (ie, across speaking samples and prolonged vowel tasks). The current study examined short-term phonatory behavior in individuals with PD, specifically examining fundamental frequency (F0) at the offset and onset of phonation, before and after a voiceless consonant. The F0 analysis at phonatory offset supported the conclusion that individuals with PD have difficulty with the rapid offset of voicing, and that they are stopping vocal fold vibration primarily through vocal fold abduction (without adding tension). The F0 analysis at phonatory onset revealed that all groups use some laryngeal tension at the initiation of voicing. The tension was lowest for the PD participants who were in their OFF medication state, and it was highest for the age-matched control participants and the PD participants in their ON medication states.