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Modeling Impacts on Space Situational Awareness PHD Filter Tracking

Computer Modeling in Engineering & Sciences 2016年第2期111卷 171-201页

作者： C.frueh Purdue University West-LafayetteINUSA.

In recent years,probabilistic tracking methods have been becoming increasingly popular for solving the multi-target tracking problem in Space Situational Awareness(SSA).Bayesian frameworks have been used to describe the objects’of interest states and cardinality as point processes.The inputs of the Bayesian framework filters are a probabilistic description of the scene at hand,the probability of clutter during the observation,the probability of detection of the objects,the probability of object survival and birth rates,and in the state update,the measurement uncertainty and process noise for the propagation.However,in the filter derivation,the assumptions of Poisson distributions of the object prior and the clutter model are made.Extracting the first-order moments of the full Bayesian framework leads to a so-called Probability Hypothesis Density(PHD)filter.The first moment extraction of the PHD filter process is extremely sensitive to both the input parameters and the measurements.The specifics of the SSA problem and its probabilistic description are illustrated in this paper and compared to the assumptions that the PHD filter is based on.As an example,this paper shows the response of a Cardinality only PHD filter(only the number of objects is estimated,not their corresponding states)to different input parameterizations.The very simple Cardinality only PHD filter is chosen in order to clearly show the sole effects of the model mismatch that might be blurred with state estimation effects,such as non-linearity in the dynamical model,in a full PHD filter implementation.The simulated multi-target tracking scenario entails the observation of attitude stable and unstable geostationary objects.

关键词： Space Situational Awareness Space Debris Finite set statistics Tracking Modeling

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Effective depth-of-penetration range due to hardness variation for different lots of nominally identical target material

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Defence Technology（防务技术） 2016年第2期12卷 171-176页

作者： Patrick frueh Andreas HEINE Karl Ernst WEBER Matthias WICKERT fraunhofer EMI Eckerstrasse 479104 FreiburgGermany

The effect of small variations of target hardness on the depth of penetration for nominally identical target material has not been addressed systematically in publications yet and is often neglected. An investigation of this issue for laboratory-scale long rod projectiles penetrating into semi-infinite rolled-homogeneous-armor steel targets was conducted. The tungsten-heavy-alloy penetrators were of length 90 mm and diameter6 mm. Five lots of armor steel with a nominal hardness range of 280–330 BHN provided material for the targets. The pursued approach consisted of hardness testing of the targets, in total 17 ballistic experiments at velocities in between 1250 m/s and 1780 m/s and data analysis.A linear regression analysis of penetration vs. hardness shows that a target hardness increase within the given range of 280–330 BHN may result in a reduction of penetration depth of about 5.8 mm at constant velocity. This is equal to a change of-12% at an impact velocity of 1250 m/s. A multiple linear regression analysis included also the influence of yaw angle and impact velocity. It shows that small yaw angles and slight variations of impact velocities provide a smaller variation of the semi-infinite penetration depths than a variation of target hardness within a typical specification span of 50 BHN. For such a span a change in penetration of approximately-4.8 mm due to hardness variation is found, whereas 1°of yaw angle or-10 m/s of velocity variation gives a change of about-1.0 mm respectively-0.9 mm. For the given example, the overwhelming part of the variation is to be attributed to hardness effects – 4.8 mm out of 5.8 mm(83%). For nominally identical target material the target hardness thus influences the ballistic test results more severely than the typical scatter in impact conditions.

关键词：硬度变化渗透深度靶材料一元线性回归分析多元线性回归分析地段穿透深度冲击速度

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Müller肌切除矫正面神经麻痹所致的睑退缩和兔眼畸形

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美国医学会眼科杂志（中文版） 2006年第2期18卷 85-89页

作者： Adam S. Hassan Bartley R. frueh Victor M. Elner 赵素焱（译）赵光喜（校） Departments of Ophthalmology Departments of Ophthalmology Departments of Pathology University of Michigan Ann Arbor

背景：面神经麻痹常由于眼睑闭合不全导致眼球刺激症状，变弱的舒张肌功能导致相对的眼睑退缩并导致兔眼畸形。目的：评估Miiller肌切除在众多的由于面神经麻痹所致眼球暴露的手术治疗中的作用。方法：34例由于患有慢性面神经麻痹患者... 详细信息

背景：面神经麻痹常由于眼睑闭合不全导致眼球刺激症状，变弱的舒张肌功能导致相对的眼睑退缩并导致兔眼畸形。目的：评估Miiller肌切除在众多的由于面神经麻痹所致眼球暴露的手术治疗中的作用。方法：34例由于患有慢性面神经麻痹患者接受了单眼结膜入路的Miiller肌切除，术后随访20个月。当需要时采用其他方法治疗下睑退缩。术前和术后对眼球暴露症状，上眼睑位置，兔眼畸形和角膜病变做了比较。结果：在59例术前症状中15例（25％）缓解，39例（66％）改善。上眼睑的位置平均降低了1．35mm（P〈0．001）。兔眼畸形（P=0．002）和角膜暴露（P〈0．001）明显改善。3例患者需要上睑提肌腱膜修复，其中2例先前存在腱膜撕裂，1例由于疏忽所致的腱膜横断。结论：Müller肌切除是一种快速。安全及可重复性的用于降低上睑位置的下眼睑退缩和减少眼球暴露症状和体征的手术方法。

关键词：面神经麻痹下眼睑退缩肌功能眼畸形切除上睑提肌腱膜刺激症状矫正眼睑闭合不全

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改进铜/镍冰铜的处理方法

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中国有色冶金 1985年第11期 23-24页

作者： E.L.frueh P.D.Parker 张焕臻

前言美国爱麦克斯(AMAX)贱金属研究和开发公司研制出一种铜/镍冰铜的处理方法,这种方法与其它方法相比能源消耗低。在芬兰奥托昆普公司的哈贾伐尔塔冶炼厂和挪威鹰桥镍公司的克里斯蒂安松精炼厂处理铜/镍冰铜的现行实践是采用电积法从... 详细信息

前言美国爱麦克斯(AMAX)贱金属研究和开发公司研制出一种铜/镍冰铜的处理方法,这种方法与其它方法相比能源消耗低。在芬兰奥托昆普公司的哈贾伐尔塔冶炼厂和挪威鹰桥镍公司的克里斯蒂安松精炼厂处理铜/镍冰铜的现行实践是采用电积法从铜富液中提取铜。

关键词：冰铜双金属电解液电解槽预浸精密合金电解池精炼(冶金) 电解精炼阳极泥电积法焙砂

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上睑退缩的前部全层分级睑切开术

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美国医学会眼科杂志（中文版） 2004年第4期16卷 244-244页

作者： VictorM.Elner AdamS.Hassan BartleyR.frueh 韩亮

背景：上睑退缩是Graves眼病的一个主要症状，它可以导致暴露性角膜病变和容貌的畸形。目的：评估治疗上睑退缩的分级前部睑切开术的效果。方法：32名患者当中的50只眼伴有Graves眼病相关性上眼睑退缩并且引起了有症状的眼部暴露，他们... 详细信息

背景：上睑退缩是Graves眼病的一个主要症状，它可以导致暴露性角膜病变和容貌的畸形。目的：评估治疗上睑退缩的分级前部睑切开术的效果。方法：32名患者当中的50只眼伴有Graves眼病相关性上眼睑退缩并且引起了有症状的眼部暴露，他们接受了分级的、穿过皮肤的、全层的、前部睑切开术。我们比较了术前和术后眼部暴露的症状，上眼睑的位置，兔眼和角膜病变。

关键词：切开术上睑退缩前部暴露角膜病变 Graves眼病眼部眼睑治疗分级

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Müller肌切除术治疗面神经麻痹引起的上睑退缩和兔眼症

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世界核心医学期刊文摘(眼科学分册) 2006年第1期 27-27页

作者： Hassan A.S. frueh B.R. Elner V.M. 宋虎平 Department of Ophthalmology University of Michigan 1000 Wall St Ann Arbor MI 48105 United States Dr

Background: Facial nerve palsy often results in symptoms of ocular irritation due to inadequate eyelid closure. Weakened protractor function results in relative upper eyelid retraction and contributes to lagophthalmos. Objective: To evaluate the role of Mü llerectomy in the comprehensive surgical treatment of ocular exposure due to facial nerve palsy. Methods: Thirty-four patients with chronic facial nerve palsy underwent unilateral transconjunctival removal of Mü ller muscle and were followed up for an average of 20 months postoperatively. Other procedures were performed to treat lower eyelid retraction, as required. Preoperative and postoperative ocular exposure symptoms, upper eyelid position, lagophthalmos, and keratopathywere compared. Results: Of the 59 preoperative symptoms, 15 (25% ) resolved and 39 (66% ) improved. Upper eyelid position was lowered by an average of 1.35 mm (P < .001). Lagophthalmos (P=.002) and corneal exposure (P < .001) were significantly improved. Three patients required levator aponeurosis repair, 2 for preexisting dehiscence and 1 for inadvertent aponeurosis transection. Conclusion: Mü llerectomy is a rapid, safe, and reproducible surgical method for lowering the upper eyelid and reducing ocular exposure symptoms and signs due to chronic facial nerve palsy.

关键词：上睑退缩面神经麻痹面瘫 ller 切除术

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