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Adaptive navigation assistance based on eye movement features in virtual reality

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Virtual Reality & Intelligent Hardware 2023年第3期5卷 232-248页

作者： Song ZHAO shiwei cheng School of Computer Science and Technology Zhejiang University of TechnologyHangzhou 310023China

Background Navigation assistance is essential for users when roaming virtual reality scenes;however,the traditional navigation method requires users to manually request a map for viewing,which leads to low immersion and poor user experience.Methods To address this issue,we first collected data on who required navigation assistance in a virtual reality environment,including various eye movement features,such as gaze fixation,pupil size,and gaze angle.Subsequently,we used the boosting-based XGBoost algorithm to train a prediction model and finally used it to predict whether users require navigation assistance in a roaming task.Results After evaluating the performance of the model,the accuracy,precision,recall,and F1-score of our model reached approximately 95%.In addition,by applying the model to a virtual reality scene,an adaptive navigation assistance system based on the real-time eye movement data of the user was implemented.Conclusions Compared with traditional navigation assistance methods,our new adaptive navigation assistance method could enable the user to be more immersive and effective while roaming in a virtual reality(VR)environment.

关键词： Eye movement Navigation Human-computer interaction Virtual reality Eye tracking

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基于随机森林算法的滁州市空气质量预报研究

环境监测管理与技术 2024年第1期36卷 74-78页

作者：华俊玮白琳邢程凌遵斌熊世为郁凌华滁州市气象局安徽滁州239004 江苏省生态环境监测监控有限公司江苏南京210019

利用2017—2019年滁州市6种空气污染物质量浓度和AQI资料、气象要素及ECMWF数值预报作为输入参数,构建基于随机森林算法的污染物质量浓度和AQI预报模型,其中AQI预报按季节划分为4个模型。结果表明:6种污染物中O_(3)的预报效果最好,相关... 详细信息

利用2017—2019年滁州市6种空气污染物质量浓度和AQI资料、气象要素及ECMWF数值预报作为输入参数,构建基于随机森林算法的污染物质量浓度和AQI预报模型,其中AQI预报按季节划分为4个模型。结果表明:6种污染物中O_(3)的预报效果最好,相关系数为0.84,PM_(2.5)、PM_(10)和NO_(2)相关系数分别为0.76、0.72和0.72,SO_(2)和CO预报效果略差;基于分季节模型AQI的24 h预报结果TS评分为0.77,空报率(FAR)和漏报率(PO)分别为15%和12%,相较于非季节模型预报效果更好;春季和秋季的TS评分分别为0.88和0.86,相较于冬季和夏季预报效果更好。

关键词：空气质量预报模型随机森林算法滁州

Non-Darcy flow in oil accumulation (oil displacing water) and relative permeability and oil saturation characteristics of low-permeability sandstones

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Petroleum Science 2010年第1期7卷 20-30页

作者： Zeng Jianhui cheng shiwei Kong Xu Guo Kai Wang Hongyu State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum Beijing 102249 China School of Natural Resources and Information Technology China University of Petroleum Beijing 102249 China CNPC Greatwall Drilling Company Beijing 100101 China

Hydrocarbon resources in low-permeability sandstones are very abundant and are extensively distributed. Low-permeability reservoirs show several unique characteristics, including lack of a definite trap boundary or caprock, limited buoyancy effect, complex oil-gas-water distribution, without obvious oil-gas-water interfaces, and relatively low oil （gas） saturation. Based on the simulation experiments of oil accumulation in low-permeability sandstone （oil displacing water）, we study the migration and accumulation characteristics of non-Darcy oil flow, and discuss the values and influencing factors of relative permeability which is a key parameter characterizing oil migration and accumulation in low-permeability sandstone. The results indicate that： 1） Oil migration （oil displacing water） in low- permeability sandstone shows non-Darcy percolation characteristics, and there is a threshold pressure gradient during oil migration and accumulation, which has a good negative correlation with permeability and apparent fluidity; 2） With decrease of permeability and apparent fluidity and increase of fluid viscosity, the percolation curve is closer to the pressure gradient axis and the threshold pressure gradient increases. When the apparent fluidity is more than 1.0, the percolation curve shows modified Darcy flow characteristics, while when the apparent fluidity up＂ non-Darcy percolation curve; 3） Oil-water is less than 1.0, the percolation curve is a ＂concave- two-phase relative permeability is affected by core permeability, fluid viscosity, apparent fluidity, and injection drive force; 4） The oil saturation of low- permeability sandstone reservoirs is mostly within 35%-60%, and the oil saturation also has a good positive correlation with the permeability and apparent fluidity.

关键词： Non-Darcy flow relative permeability oil saturation low-permeability sandstone

EasyGaze:Hybrid eye tracking approach for handheld mobile devices

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Virtual Reality & Intelligent Hardware 2022年第2期4卷 173-188页

作者： shiwei cheng Qiufeng PING Jialing WANG Yijian CHEN School of Computer Science and Technology Zhejiang University of TechnologyHangzhou 310023China

Background Eye-tracking technology for mobile devices has made significant progress.However,owing to limited computing capacity and the complexity of context,the conventional image feature-based technology cannot extract features accurately,thus affecting the performance.Methods This study proposes a novel approach by combining appearance-and feature-based eye-tracking methods.Face and eye region detections were conducted to obtain features that were used as inputs to the appearance model to detect the feature points.The feature points were used to generate feature vectors,such as corner center-pupil center,by which the gaze fixation coordinates were calculated.Results To obtain feature vectors with the best performance,we compared different vectors under different image resolution and illumination conditions,and the results indicated that the average gaze fixation accuracy was achieved at a visual angle of 1.93°when the image resolution was 96×48 pixels,with light sources illuminating from the front of the eye.Conclusions Compared with the current methods,our method improved the accuracy of gaze fixation and it was more usable.

关键词： Eye movement Gaze estimation Fixation Human-computer interaction Eye tracking

HPMA modified aluminium nitride powder for aqueous tape casting of AlN ceramic substrates

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Journal of Advanced Ceramics 2023年第9期12卷 1701-1711页

作者： Meng Li Jianping Ai Zhengjuan Wang Zhenhai Xue Lihong cheng Guohong Zhou shiwei Wang School of Materials and Mechatronics Jiangxi Science&Technology Normal UniversityNanchang 330038China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China

Aluminum nitride(AlN)is considered one of the most desirable materials for integrated circuits and electronic packaging substrates.However,raw AlN powder reacts easily with water,forming Al(OH)3 or AlOOH on the surface and hindering the development of an aqueous tape-casting process for preparing AlN ceramic substrates.In this study,hydrolyzed polymaleic anhydride(HPMA)was used to modify AlN powder,which has good water solubility and dispersibility.The AlN powder was modified with 5 wt%HPMA remained stable in water for at least 90 h under magnetic stirring condition and 24 h under ball milling condition,indicating that HPMA-modified AlN powder has good resistance to hydrolysis.The action mechanism of HPMA is revealed.Firstly,–COOH of the HPMA polymer and the oxide layer on the surface of the AlN powder underwent a dehydration condensation reaction to form a compound.Secondly,long chains of the polymer further coated the surface of the AlN powder,forming an anti-hydration layer with a thickness of about 7.0 nm on the surface of the AlN particles.In addition,AlN green sheets were successfully prepared by aqueous tape casting using the HPMA-modified AlN powder without additional dispersants.Subsequently,AlN ceramic substrates were obtained by sintering at 1750℃for 4 h under an N2 atmosphere with a pressure of 0.2 MPa.The relative density and thermal conductivity were tested to be 97.3%and 122 W/(m·K),respectively.

关键词： aluminum nitride(AlN) surface modification hydrolyzed polymaleic anhydride(HPMA) hydrolysis resistance aqueous tape casting

Extraction of Alpha transmitter signals from single-station observations using the direction-finding method

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Science China(Technological Sciences) 2022年第8期65卷 1727-1737页

作者： GU XuDong CHEN Huan WANG shiwei LU ZiLong NI BinBin LI GuangJian cheng Wen Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China

For the applications of Alpha very-low-frequency(VLF) systems consisting of multiple transmitters, determining the origin transmitter station of received signals is a crucial problem. Based on single-station observations, this study develops a directionfinding method to extract Russian Alpha transmitter signals. First, the amplitudes of Alpha signals received in Suizhou City,Hubei Province(31.57°N, 113.32°E) in the east-west(EW) and north-south(NS) directions are obtained by the power spectrum method. The amplitude ratios of signals in the two directions are subsequently adopted to estimate the propagation angles of the signals with respect to the NS direction of the VLF receiver station. Phase ambiguity in our system is eliminated by comparing Alpha signal waveform with that from the VTX transmitter in India(8.39°N, 77.75°E) as a reference station. Finally, we can determine the quadrant where the incoming wave signals are located relative to the receiver and eventually distinguish the exact Alpha transmitters. Based on the direction-finding results, the amplitudes of each Alpha signal are extracted, and their diurnal variation features are analyzed to verify the performance of our method. These results are of great significance for the further study of Alpha signals and VLF long-distance communication.

关键词： very low frequency signal alpha transmitter direction-finding method single-station observation

准噶尔盆地重点领域油气勘探研究进展及潜力方向

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油气地质与采收率 2024年第4期31卷 24-41页

作者：王金铎张关龙庄新明宫亚军张翊曲彦胜薛雁程世伟中国石化胜利油田分公司勘探开发研究院山东东营257015

准噶尔盆地胜利探区主要位于盆地周缘超剥带、复杂山前带和深洼区,油气成藏条件复杂,勘探难度大。为明确胜利探区重点领域的潜力方向,指导下步油气勘探部署层次优选,基于胜利探区准西缘超剥带领域、准中地区上组合深层领域、准中地区下... 详细信息

准噶尔盆地胜利探区主要位于盆地周缘超剥带、复杂山前带和深洼区,油气成藏条件复杂,勘探难度大。为明确胜利探区重点领域的潜力方向,指导下步油气勘探部署层次优选,基于胜利探区准西缘超剥带领域、准中地区上组合深层领域、准中地区下组合超深层领域、准北缘及准东南山前带领域沉积、储层、油源对比、输导体系、成藏模式、油气富集控制因素等勘探研究进展系统总结,对各重点领域下步的潜力方向进行了分析。结果表明:准西缘超剥带领域的哈山地区侏罗系—白垩系、车排子地区新近系沙湾组、车排子地区石炭系及准中地区上组合深层领域的永进-征沙村地区侏罗系齐古组、莫西庄地区侏罗系三工河组及东道海子凹陷成6井区侏罗系八道湾组是下步主要的增储上产阵地;准中地区下组合超深层领域的沙湾凹陷征10井区二叠系上乌尔禾组—三叠系克拉玛依组、盆1井西凹陷庄深1井区二叠系风城组—夏子街组是下步重要的接替阵地;准北缘哈山山前带及准东南博格达山南、北山前带准原地系统是下步需要持续探索的有利阵地;石北凹陷及石钱滩凹陷石炭系深层非常规页岩气领域是今后需要积极准备的后备阵地。“十四五”—“十五五”期间,胜利探区应以“立足全区、决胜深层、常非并重、统筹推进”勘探思路为指导,持续、有序地推进盆地各重点领域的勘探。

关键词：勘探历程含油气系统重点领域勘探研究进展潜力方向准噶尔盆地

轮廓扫描速度对SLM成形TC1钛合金侧面质量的影响

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粉末冶金工业 2024年第2期34卷 44-48页

作者：胡家齐董定平慈世伟蔡小叶谢隋杰程宗辉国营芜湖机械厂安徽芜湖241000

采用选区激光熔化(Selective laser melting,SLM)工艺以不同的轮廓扫描速度制备了TC1钛合金样品,测定了样品的侧面粗糙度,观察了样品侧面近表面缺陷特征并测试了其显微硬度。结果表明:随轮廓扫描速度的增加,样品的侧面粗糙度Ra由8.09μ... 详细信息

采用选区激光熔化(Selective laser melting,SLM)工艺以不同的轮廓扫描速度制备了TC1钛合金样品,测定了样品的侧面粗糙度,观察了样品侧面近表面缺陷特征并测试了其显微硬度。结果表明:随轮廓扫描速度的增加,样品的侧面粗糙度Ra由8.09μm提升至12.27μm,这主要是由于球化与表面粘附的部分熔化粉末导致的。当轮廓扫描速度较慢时(300 mm/s),产生匙孔效应,近表面形成了大量气孔缺陷。当轮廓扫描速度较高时(900 mm/s),能量密度较低,近表面区域形成了未熔合缺陷。此外,低的轮廓扫描速度使能量密度增加,轮廓区熔池冷却速度减小,从而使近表面区域的硬度降低。高的轮廓扫描速度有助于降低近表面区域硬度的损失。

关键词：轮廓扫描速度表面粗糙度气孔未熔合显微硬度

基于DRG支付的药事管理干预对基层医院静脉输液合理使用的影响

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中国药业 2024年第2期33卷 6-10页

作者：葛欣刘平张士伟朱妍莹程慎令山东省滕州市中心人民医院山东枣庄277500

目的促进医院合理使用静脉输液。方法基于疾病诊断相关分组(DRG)支付进行药事管理干预,干预时间为2021年10月至12月,干预手段包括加强宣传教育培训,梳理静脉输液药品品种与疾病谱,制订病种相应临床路径,增加输液处方专项点评内容,将不... 详细信息

目的促进医院合理使用静脉输液。方法基于疾病诊断相关分组(DRG)支付进行药事管理干预,干预时间为2021年10月至12月,干预手段包括加强宣传教育培训,梳理静脉输液药品品种与疾病谱,制订病种相应临床路径,增加输液处方专项点评内容,将不合理处方开具情况纳入绩效考核,开展信息系统管控。通过医院信息系统与合理用药软件提取医院门/急诊与住院部2021年1月至9月(药事管理干预前)与2022年1月至9月(药事管理干预后)的病例资料,分析干预前后全部处方及含抗菌药物、含中药注射剂、含激素类药物(或辅助药品)处方中静脉输液相关指标及住院病例DRG相关药事指标。结果静脉输液相关指标,与干预前比较,干预后的门/急诊患者总体及不同类型药物静脉输液率(以人次、处方数计)均显著降低(P<0.01),住院患者除抗菌药物外的静脉输液率(以人次计)均显著降低(P<0.01);门/急诊与住院患者药品使用金额均不同幅度降低;门/急诊患者处方退回修改率显著升高(3.54%比2.41%,P<0.01);患者对静脉输液服务的总满意度显著升高(94.20%比73.20%,P<0.01)。DRG相关指标,与干预前比较,干预后的住院患者DRG总权重、病例组合指数(CMI)及基本药物使用金额占比均升高,费用消耗指数、时间消耗指数和患者次均费用均降低,且患者死亡率及静脉输液药品结构比、辅助药品结构比、次均药费、次均辅助药费均降低。结论该药事管理模式显著降低了静脉输液率,并提高了医院合理用药水平,减少了患者的就医费用,并提高了患者满意度,继而整体提升了该院的医疗服务能力。

关键词： DRG支付基层医院药事管理静脉输液率合理用药