检索结果-南通市图书馆

Transferring priors from virtual data for crowd counting in real world

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2022年第3期16卷 1-8页

作者： Xiaoheng JIANG Hao LIU Li ZHANG Geyang LI Mingliang XU pei lv Bing ZHOU School of Information Engineering Zhengzhou UniversityZhengzhou 450001China School of Information Engineering Henan University of Science and TechnologyLuoyang 471000China

In recent years,crowd counting has increasingly drawn attention due to its widespread applications in the field of computer vision.Most of the existing methods rely on datasets with scarce labeled images to train networks.They are prone to suffer from the over-fitting problem.Further,these existing datasets usually just give manually labeled annotations related to the head center position.This kind of annotation provides limited information.In this paper,we propose to exploit virtual synthetic crowd scenes to improve the performance of the counting network in the real world.Since we can obtain people masks easily in a synthetic dataset,we first learn to distinguish people from the background via a segmentation network using the synthetic data.Then we transfer the learned segmentation priors from synthetic data to real-world data.Finally,we train a density estimation network on real-world data by utilizing the obtained people masks.Our experiments on two crowd counting datasets demonstrate the effectiveness of the proposed method.

关键词： crowd counting synthetic data virtual-real combination people segmentation density estimation

Trajectory distributions:A new description of movement for trajectory prediction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computational Visual Media 2022年第2期8卷 213-224页

作者： pei lv Hui Wei Tianxin Gu Yuzhen Zhang Xiaoheng Jiang Bing Zhou Mingliang Xu School of Information Engineering Zhengzhou UniversityZhengzhou 450001China

Trajectory prediction is a fundamental and challenging task for numerous applications,such as autonomous driving and intelligent robots.Current works typically treat pedestrian trajectories as a series of 2D point coordinates.However,in real scenarios,the trajectory often exhibits randomness,and has its own probability distribution.Inspired by this observation and other movement characteristics of pedestrians,we propose a simple and intuitive movement description called a trajectory distribution,which maps the coordinates of the pedestrian trajectory to a 2D Gaussian distribution in space.Based on this novel description,we develop a new trajectory prediction method,which we call the social probability method.The method combines trajectory distributions and powerful convolutional recurrent neural networks.Both the input and output of our method are trajectory distributions,which provide the recurrent neural network with sufficient spatial and random information about moving pedestrians.Furthermore,the social probability method extracts spatio-temporal features directly from the new movement description to generate robust and accurate predictions.Experiments on public benchmark datasets show the effectiveness of the proposed method.

关键词： trajectory prediction convolutional LSTM trajectory distributions social probabihty method

在线全文

学校读者我要写书评

暂无评论

某全回转救助拖船船体结构振动分析

船海工程 2024年第2期53卷 72-75页

作者：蔡晓涛黄志武叶林昌王烨吕佩瑶船舶与海洋工程特种装备和动力系统国家工程研究中心上海201108 中国船舶集团有限公司第七一一研究所上海201108

针对全回转救助拖船在螺旋桨最大转速时出现的船体结构振动问题,通过实船振动测试分析,判断引起船体结构振动的激励源来自艉部螺旋桨,而螺旋桨激励引起船体结构强迫振动和共振。在采取船艉结构加强,敷设阻尼减振材料的方法进行振动控制... 详细信息

针对全回转救助拖船在螺旋桨最大转速时出现的船体结构振动问题,通过实船振动测试分析,判断引起船体结构振动的激励源来自艉部螺旋桨,而螺旋桨激励引起船体结构强迫振动和共振。在采取船艉结构加强,敷设阻尼减振材料的方法进行振动控制后,实船测试表明,船体结构振动速度最大降低7.23 mm/s。

关键词：全回转舵桨螺旋桨激励振动控制共振强迫振动

在线全文

学校读者我要写书评

暂无评论

船舶发电机组排烟管系低振动设计及试验

船海工程 2024年第3期53卷 55-59页

作者：朱强强蔡晓涛吕佩瑶李瑞尧黄志武中船黄埔文冲船舶有限公司广州511462 中国船舶集团有限公司第七一一研究所上海201108

为降低排烟管系振动和噪声传递到船体结构和附近舱室,需对其进行低振动设计,在考虑减振的基础上,考虑排烟管系的自振频率,选择合适减振元件,采用有限元分析方法计算排烟管系的模态,并在实船上进行隔振效果的测试验证。实船结果表明,在10... 详细信息

为降低排烟管系振动和噪声传递到船体结构和附近舱室,需对其进行低振动设计,在考虑减振的基础上,考虑排烟管系的自振频率,选择合适减振元件,采用有限元分析方法计算排烟管系的模态,并在实船上进行隔振效果的测试验证。实船结果表明,在10~10 kHz频段范围内,排烟管系减振装置有较好的隔振效果,隔振效果达到15 dB以上;并有效避免了整个系统共振的发生而导致设备破坏和产生严重的振动噪声现象。

关键词：排烟管系隔振效果低振动设计固有频率

在线全文

学校读者我要写书评

暂无评论

基于战略分析方法的大型医疗设备管理研究

中国医疗器械信息 2024年第11期30卷 154-156页

作者：吕佩颖邵晓宁刘良孟炯程敬亮郑州大学第一附属医院磁共振科河南郑州450052

医疗设备管理是医院管理的重要组成部分,却时常陷入“管理难、质控难、维保难、效益分析难”的困境。采用管理经济学领域的两种战略分析方法——SWOT分析法和八何分析法,对医院大型医疗设备管理过程中遇到的问题和现象进行分析,并从医... 详细信息

医疗设备管理是医院管理的重要组成部分,却时常陷入“管理难、质控难、维保难、效益分析难”的困境。采用管理经济学领域的两种战略分析方法——SWOT分析法和八何分析法,对医院大型医疗设备管理过程中遇到的问题和现象进行分析,并从医院管理角度提出相关建议与解决方案,旨在全面掌握管理现状中的难点与重点,有效提高医疗设备的工作效率,尽可能发挥其所具备的功能和性能。同时,对设备管理工作的分析和规划有助于降低运营成本,提高医院经济效益,为医院开展精细化、科学化、系统化的管理模式提供决策依据。

关键词：战略分析方法大型医疗设备 SWOT分析法八何分析法医院管理

Permanent lining castable with low bulk density and thermal conductivity:bauxite castable for tundish obtained by adding pearlescent sand

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2024年第3期31卷 634-646页

作者： Yi Wang Jian Yang Bao Wang Hai-jun Zhang Juan Han pei-yan pei Wen-long lv Jian-an Zhou The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina Wuhan Research Institute of Metallurgical Construction MCCWuhan 430081HubeiChina

The low thermal conductivity and light mass of castables for tundish permanent linings are crucial for minimizing the heat loss of molten steel.In consideration of the low bulk density and thermal conductivity of pearlescent sand,the thermal insulation performance of castables was attempted to be improved by adding pearlescent sand.Pearlescent sand was modified to prevent the strength of its porous structure from deteriorating.The modification mechanism of pearlescent sand and the effect of pearlescent sand on the performance of bauxite castables were studied.The results suggested that the addition of the modified pearlescent sand significantly raised the apparent porosity and decreased the bulk density of bauxite castable.At 1000℃,the bulk density of more than 60%of the modified pearlescent sand-bauxite castable was only 2.03 g/cm^(3).The mechanical properties and thermal shock resistance of the modified pearlescent sand-bauxite castable were inferior to those of conventional bauxite castable but were adequate to meet the use conditions of casta-bles for tundish permanent linings.At high temperatures of 200-800℃,the thermal conductivity of more than 60%of the modified pearlescent sand-bauxite castable was smaller than that of conventional bauxite castable.The addition of the modified pearlescent sand can greatly reduce the thermal conductivity and bulk density of bauxite castable.

关键词： Pearlescent sand-Hydrophobic modification Bauxite castable Thermal insulation performance Mechanical property

Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第4期12卷 1449-1460页

作者： Guishang pei Cheng Pan Dapeng Zhong Junyi Xiang Xuewei lv College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China Pangang Group Research Institute Co. Ltd.Panzhihua 617000China

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted considerable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air atmosphere.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kJ/mol.The endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kJ/mol,which is related to the incongruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high temperatures.The cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is controlled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating rate.Additionally,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(J mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

关键词： MgV_(2)O_(6) Crystal structure Phase transitions Thermodynamic functions

磁共振动态增强图像及定量参数诊断富细胞型子宫肌瘤的价值及与生物学行为标志物的相关性

在线全文

学校读者我要写书评

暂无评论

海南医学 2024年第4期35卷 547-552页

作者：郭伟吕培培谷梅兰董安珂陈亚龙肖新广上官建伟郑州市中心医院放射科河南郑州450000 新郑市公立人民医院放射科河南新郑451151

目的探讨磁共振动态增强图像(DCE-MRI)及定量参数诊断富细胞型子宫肌瘤(CUL)的价值及其与生物学行为标志物的相关性。方法选取2021年6月至2023年6月于郑州市中心医院就诊的83例CUL患者作为观察组,另选取同期、同年龄段普通型子宫肌瘤患... 详细信息

目的探讨磁共振动态增强图像(DCE-MRI)及定量参数诊断富细胞型子宫肌瘤(CUL)的价值及其与生物学行为标志物的相关性。方法选取2021年6月至2023年6月于郑州市中心医院就诊的83例CUL患者作为观察组,另选取同期、同年龄段普通型子宫肌瘤患者83例作为对照组,两组患者均进行DCE-MRI检查,并测定观察组患者病灶组织p16、血管内皮生长因子(VEGF)、Ki-67。比较两组患者的DCE-MRI定量参数[速率常数(Kep)、血管间隙容积分数(Vp)、容量转运常数(Ktrans)、血管外细胞外间隙容积分数(Ve)、毛细血管表面通透性(PS)、血浆灌流量(Fp)],采用相对危险度(RR)分析不同水平DCE-MRI定量参数(Ktrans、Kep、Ve、Vp、PS及Fp)对CUL的发病风险,采用受试者工作特征曲线(ROC)、决策(DCA)曲线评估DCE-MRI定量参数对CUL的诊断效能;比较不同p16、VEGF、Ki-67表达CUL患者的DCE-MRI定量参数,采用Pearson分析DCE-MRI定量参数与p16、VEGF、Ki-67的相关性。结果观察组患者的Ktrans、Kep、Ve、Vp、PS及Fp分别为(1.98±0.62)min、(1.99±0.24)min、(0.80±0.17)%、(0.52±0.14)%、(1.24±0.45)mL/min、(2.47±0.46)mL/min,明显高于对照组的(0.96±0.35)min、(1.12±0.43)min、(0.55±0.22)%、(0.29±0.10)%、(0.37±0.12)mL/min、(0.91±0.25)mL/min,差异均有统计学意义(P<0.05);当Kep、Ktrans、Ve、Vp、PS及Fp高水平时,CUL发病风险是低水平的9.375倍、6.546倍、3.611倍、4.929倍、8.222倍、5.917倍;经ROC分析结果显示,Ktrans、Kep、Ve、Vp、PS、Fp联合诊断CUL的AUC为0.939,大于各参数单独诊断(P<0.05);经DCA曲线分析结果显示,各参数联合诊断CUL的临床净收益率最高;观察组中p16、VEGF及Ki-67阳性表达患者的Ktrans、Kep、Ve、Vp、PS及Fp明显高于阴性表达患者,差异均有统计学意义(P<0.05);经Pearson分析结果显示,Kep、Ktrans、Ve、Vp、PS及Fp与p16、VEGF、Ki-67均呈正相关(P<0.05)。结论DCE-MRI及定量参数对CUL具有一定诊断价值,且与患者p16、VEGF及Ki-67显著相关。

关键词：富细胞型子宫肌瘤磁共振动态增强图像定量参数诊断应用价值

Association of physical activity with risk of chronic kidney disease in China:A population-based cohort study

在线全文

学校读者我要写书评

暂无评论

Journal of Sport and Health Science 2024年第2期13卷 204-211页

作者： Kexiang Shi Yunqing Zhu Jun lv Dianjianyi Sun pei pei Huaidong Du Yiping Chen Ling Yang Bing Han Rebecca Stevens Junshi Chen Zhengming Chen Liming Li Canqing Yu China Kadoorie Biobank collaborative group Department of Epidemiology&Biostatistics School of Public HealthPeking University Health Science CenterBeijing 100191China Peking University Center for Public Health and Epidemic Preparedness&Response Beijing 100191China Key Laboratory of Epidemiology of Major Diseases(Peking University) Ministry of EducationBeijing 100191China Clinical Trial Service Unit&Epidemiological Studies Unit(CTSU) Nuffield Department of Population HealthUniversity of OxfordOxford OX37LFUK Medical Research Council Population Health Research Unit at the University of Oxford Oxford OX37LFUK NCDs Prevention and Control Department Henan Center for Disease Control and PreventionZhengzhou 450016China China National Center for Food Safety Risk Assessment Beijing 100022China 不详

Background:Information on the association between physical activity(PA)and the risk of chronic kidney disease(CKD)is limited.We aimed to explore the associations of total,domain-specific,and intensity-specific PA with CKD and its subtypes in China.Methods:The study included 475,376 adults from the China Kadoorie Biobank aged 30-79 years during 2004-2008 at baseline.An interviewer-administered questionnaire was used to collect the information about PA,which was quantified as metabolic equivalent of task hours per day(MET-h/day)and categorized into 4 groups based on quartiles.Cox regression was used to analyze the association between PA and CKD risk.Results:During a median follow-up of 12.1 years,5415 incident CKD cases were documented,including 1159 incident diabetic kidney disease(DKD)cases and 362 incident hypertensive nephropathy(HTN)cases.Total PA was inversely associated with CKD risk,with an adjusted hazard ratio(HR,95%confidence interval(95%CI))of 0.83(0.75-0.92)for incident CKD in the highest quartile of total PA as compared with participants in the lowest quartile.Similar results were observed for risk of DKD and HTN,and the corresponding HRs(95%CIs)were 0.75(0.58-0.97)for DKD risk and 0.56(0.37-0.85)for HTN risk.Increased nonoccupational PA,low-intensity PA,and moderate-to-vigorous-intensity PA were significantly associated with a decreased risk of CKD,with HRs(95%CIs)of 0.80(0.73-0.88),0.85(0.77-0.94),and 0.85(0.76-0.95)in the highest quartile,respectively.Conclusion:PA,including nonoccupational PA,low-intensity PA,and moderate-to-vigorous-intensity PA,was inversely associated with the risk of CKD,including DKD,HTN,and other CKD,and such associations were dose dependent.

关键词： Chronic kidney disease Domain Intensity Physical activity