检索结果-南通市图书馆

Sensitivity analysis of parameters and contrasting performance of ground filtering algorithms with UAV photogrammetry-based and LiDAR point clouds

引用

International Journal of Digital Earth 2020年第12期13卷 1672-1694页

作者： Petr klápště Michal Fogl Vojtěch Barták kateřina Gdulová Rudolf Urban Vítězslav Moudrý Department of Applied Geoinformatics and Spatial Planning Faculty of Environmental SciencesCzech University of Life Sciences PragueKamýcká129Praha-Suchdol16500Czech Republic Department of Special Geodesy Faculty of Civil EngineeringCzech Technical University in PraguePragueCzech Republic

Most ground filtering algorithms are primarily designed for airborne LiDAR point cloud processing and their successful use in identifying ground points from photogrammetric point clouds remains questionable.We compared six ground filtering algorithms implemented in Metashape,ArcGIS,CloudCompare,LAStools,and PDAL.We used UAV photogrammetry-based(acquired under leaf-off conditions)and airborne LiDAR(leaf-on)point clouds of the same area to:(i)compare accuracy of generated DTMs;(ii)evaluate the effect of vegetation density and terrain slope on filtering accuracy;and(iii)assess which algorithm parameters have the greatest effect on the filtering accuracy.Our results show that the performance of filtering algorithms was affected by the point cloud type,terrain slope and vegetation cover.The results were generally better for LiDAR(RMSE 0.13–0.19 m)than for photogrammetric(RMSE 0.19–0.23 m)point clouds.The behavior in varying vegetation and terrain conditions was consistent for LiDAR point clouds.However,when applied on photogrammetric point clouds,the algorithms’behavior was inconsistent,especially in areas of steep slope(except for the Progressive Triangulated Irregular Network in LAStools).Parameters related to the selection of the initial minimum elevation ground points were the most influential in all algorithms and point clouds.

关键词： DTM filtering LiDAR point cloud spoil heap UAV

来源：

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

Promoting axon regeneration in the central nervous system by increasing PI3-kinase signaling

引用

Neural Regeneration Research 2022年第6期17卷 1172-1182页

作者： bart Nieuwenhuis Richard Eva John van Geest Center for Brain Repair Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK

Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous system.Axons in the central nervous system fail to regenerate,meaning that injuries or diseases that cause loss of axonal connectivity have life-changing consequences.In 2008,genetic deletion of PTEN was identified as a means of stimulating robust regeneration in the optic nerve.PTEN is a phosphatase that opposes the actions of PI3-kinase,a family of enzymes that function to generate the membrane phospholipid PIP_(3) from PIP_(2)(phosphatidylinositol(3,4,5)-trisphosphate from phosphatidylinositol(4,5)-bisphosphate).Deletion of PTEN therefore allows elevated signaling downstream of PI3-kinase,and was initially demonstrated to promote axon regeneration by signaling through mTOR.More recently,additional mechanisms have been identified that contribute to the neuron-intrinsic control of regenerative ability.This review describes neuronal signaling pathways downstream of PI3-kinase and PIP3,and considers them in relation to both developmental and regenerative axon growth.We briefly discuss the key neuron-intrinsic mechanisms that govern regenerative ability,and describe how these are affected by signaling through PI3-kinase.We highlight the recent finding of a developmental decline in the generation of PIP_(3) as a key reason for regenerative failure,and summarize the studies that target an increase in signaling downstream of PI3-kinase to facilitate regeneration in the adult central nervous system.Finally,we discuss obstacles that remain to be overcome in order to generate a robust strategy for repairing the injured central nervous system through manipulation of PI3-kinase signaling.

关键词： axon cytoskeleton axon regeneration axon transport cell signaling central nervous system growth cone neuroprotection PI3-kinase PI3k PTEN trafficking transcription translation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Generating synthetic as-built additive manufacturing surface topography using progressive growing generative adversarial networks

引用

Friction 2024年第6期12卷 1283-1298页

作者： Junhyeon SEO Prahalada RAO bart RAEYMAEkERS Department of Mechanical Engineering Virginia TechBlacksburgVA 24061USA Grado Department of Industrial and Systems Engineering Virginia TechBlacksburgVA 24061USA

Numerically generating synthetic surface topography that closely resembles the features and characteristics of experimental surface topography measurements reduces the need to perform these intricate and costly measurements.However,existing algorithms to numerically generated surface topography are not well-suited to create the specific characteristics and geometric features of as-built surfaces that result from laser powder bed fusion(LPBF),such as partially melted metal particles,porosity,laser scan lines,and balling.Thus,we present a method to generate synthetic as-built LPBF surface topography maps using a progressively growing generative adversarial network.We qualitatively and quantitatively demonstrate good agreement between synthetic and experimental as-built LPBF surface topography maps using areal and deterministic surface topography parameters,radially averaged power spectral density,and material ratio curves.The ability to accurately generate synthetic as-built LPBF surface topography maps reduces the experimental burden of performing a large number of surface topography measurements.Furthermore,it facilitates combining experimental measurements with synthetic surface topography maps to create large data-sets that facilitate,e.***.relating as-built surface topography to LPBF process parameters,or implementing digital surface twins to monitor complex end-use LPBF parts,amongst other applications.

关键词： additive manufacturing surface topography synthetic surface topography generative adversarial networks

来源：

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

Guest editorial:Special Issue on Artificial Intelligence and Emerging Computational Approaches for Tribology

引用

Friction 2024年第6期12卷 1057-1059页

作者： Zhinan ZHANG Shuaihang PAN bart RAEYMAEkERS State key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering University of UtahSalt Lake CityUT 84112USA Department of Mechanical Engineering Virginia TechBlacksburgVA 24061USA

Tribo-behavior is a complex system-based time-dependent process,and it is difficult to accurately model a tribo-system and predict its behavior.Hence,tribology research,in most cases,has relied on extensive experimentation.Driven by the artificial intelligence(AI)-for-science revolution,AI and other emerging computational approaches provide opportunities to explore the complex processes in tribo-systems and the physical mechanisms of tribo-behavior in an efficient way,significantly pushing the boundaries of tribology research.

关键词： behavior. editorial artificial

来源：

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

Determination of the sensible heat effectiveness and pressure loss of a rotary regenerative heat exchanger using CFD

引用

Building Simulation 2023年第6期16卷 869-887页

作者： Vladimír Zmrhal Petr Zelenský Jindřich Boháč Martin barták Miroslav kučera Roman Vavřička Faculty of Mechanical Engineering Department of Environmental EngineeringCzech Technical University in PragueTechnická416000Prague 6Czech Republic

The paper presents a new method to determine the sensible effectiveness and pressure loss of rotary regenerative heat exchangers using computational fluid dynamics(CFD).It is based on CFD simulations of a single thermal wheel microchannel with a small cross-sectional area and thin walls,with cyclic inlet and outlet boundary conditions.Two unique measurement set-ups were designed and built for the experimental measurement of the heat exchanger characteristics.Five different types of thermal wheels were manufactured,measured,and simulated in ANSYS Fluent.All wheels achieve an effectiveness greater than 73%under certain(air flow)conditions,which is the minimum effectiveness required by Ecodesign(in the EU).For the examined exchangers,the effectiveness ranges from 66.5%to 83.3%,depending on the boundary conditions and geometric parameters of the rotors.The highest sensible effectiveness is achieved by heat exchangers with the largest heat exchange surface Ac;on the other hand,these wheels have the largest pressure loss.The paper discusses the use of a simplifiedε-NTU correlation model for the HVAC systems(typically C*=1).The correlation model and CFD results were compared and found to be different from each other.The results of the CFD simulation were compared with measurements to prove that the proposed simulation method can predict the behaviour of the real heat exchanger as a whole.It was demonstrated that the sensible effectiveness and pressure loss of the rotary heat exchanger predicted by the CFD simulations correspond well to the measured values within the measurement uncertainty±1.3%.The proposed method can be used for the comparison of different rotary regenerative heat exchangers before their manufacturing and for verification that they meet the EU Ecodesign requirements set by the current legislation.It reduces the cost of the initial optimisation and testing of new designs.

关键词： rotary heat exchanger heat wheel microchannel heat recovery sensible effectiveness pressureloss computer fluid dynamics experiment

来源：

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

The differential genetic signatures related to climatic landscapes for jaguars and pumas on a continental scale

引用

Integrative Zoology 2021年第1期16卷 2-18页

作者： Marina ZANIN Noa GONZALEZ-BORRAJO Cuauhtémoc chÁVEZ Yamel RUBIO bart HARMSEN Claudia kELLER Pablo VILLALVA Ana Carolina SRBEk-ARAUJO Leonora Pires COSTA Francisco PALOMARES Biology Department Federal University of MaranhãoSão LuísBrazil Departamento de Biologia de la Conservación Estación Biológica de DoñanaSevillaSpain Departamento de Ciencias Ambientales Universidad Autónoma MetropolitanaMexico CityMexico Escuela de Biologia Universidad Autónoma de SinaloaCuliacánMexico Panthera New YorkUSA Biodiversity Coordination Amazon Research InstituteManausBrazil Biology Department Vila Velha UniversityVila VelhaBrazil Biological Sciences Department Federal University of Espírito SantoVitóriaBrazil

Modern and paleoclimate changes may have altered species dynamics by shifting species’niche suitability over space and time.We analyze whether the current genetic structure and isolation of the two large American felids,jaguar(Panthera onca)and puma(Puma concolor),are mediated by changes in climatic suitability and connection routes over modern and paleoclimatic landscapes.We estimate species distribution under 5 climatic landscapes(modern,Holocene,last maximum glaciations[LMG],average suitability,and climatic instability)and correlate them with individuals’genetic isolation through causal modeling on a resemblance matrix.Both species exhibit genetic isolation patterns correlated with LMG climatic suitability,suggesting that these areas may have worked as“allele refuges.”However,the jaguar showed higher vulnerability to climate changes,responding to modern climatic suitability and connection routes,whereas the puma showed a continuous and gradual transition of genetic variation.Despite differential responsiveness to climate change,both species are subjected to the climatic effects on genetic configuration,which may make them susceptible to future climatic changes,since these are progressing faster and with higher intensity than changes in the paleoclimate.Thus,the effects of climatic changes should be considered in the design of conservation strategies to ensure evolutionary and demographic processes mediated by gene flow for both species.

关键词： causal modeling climatic landscape ecological niche modeling gene flow linear mixed model

来源：

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

Linking axon transport to regeneration using in vitro laser axotomy

引用

Neural Regeneration Research 2018年第3期13卷 410-412页

作者： bart Nieuwenhuis Richard Eva John van Geest Centre for Brain Repair Department of Clinical Neurosciences University of Cambridge Cambridge UK Laboratory for Regeneration of Sensorimotor Systems Netherlands Institute for Neuroscience Royal Netherlands Academy of Arts and Sciences (KNAW) Amsterdam The Netherlands

Spinal cord injury has devastating consequences because adult central nervous system （CNS） neurons do not regenerate their axons after injury. Two key reasons for axon regeneration fail- ure are extrinsic inhibitory factors and a low intrinsic capacity for axon regrowth. Research has therefore focused on overcom- ing extrinsic growth inhibition, and enhancing intrinsic regeneration capacity. Both of these issues will need to be addressed to enable optimal repair of the injured sp＋inal cord.

关键词： CNS ARF Linking axon transport to regeneration using in vitro laser axotomy EFA

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Defining the Value of Extracorporeal Liver Support in Acute and Acute-on-chronic Liver Failure

引用

Journal of Clinical and Translational Hepatology 2023年第3期11卷 517-520页

作者： bart van Hoek Department of Gastroenterology and Hepatology C4-Pand Transplantation CenterLeiden University Medical CenterLei denthe Netherlands

Next to acute liver failure(ALF)without previous liver dis-ease,the concept of acute-on-chronic liver failure(ACLF)has been developed.1,2 In most cases patients developing ACLF first have acute decompensation(AD)of cirrhosis,of-ten with ascites,hepatic encephalopathy,variceal bleeding,or hepatorenal syndrome.AD can be induced by infection or other factors,like hepatitis exacerbation.Both ALF and ACLF develop rapidly,ALF within 26 weeks of onset,ACLF in 2-4 weeks,and both conditions share the symptoms of a fail-ing liver.Decreased detoxification with jaundice and hepatic encephalopathy,and impaired synthetic capacity of the liver with changes in coagulation parameters are part of these syndromes.In both ALF and ACLF multi-organ failure can de-velop,including hemodynamic instability,respiratory failure and acute kidney injury,and patients become susceptible to infections.Although standard medical treatment(SMT)in the intensive care unit has improved over the years,2,3 both con-ditions often lead toward death,unless a timely liver trans-plantation(LT)is possible.4,5.

关键词： acute impaired Acute

来源：

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

Electrochemically-stimulated nanoscale mechanochemical wear of silicon

引用

摩擦:英文版 2023年第11期11卷 2142-2152页

作者： chen XIAO Stefan VAN VLIET Roland BLIEM bart WEBER Steve FRANkLIN Advanced Research Center for Nanolithography(ARCNL) Amsterdam 1098XGthe Netherlands Van der Waals–Zeeman Institute Institute of PhysicsUniversity of Amsterdam(UvA)Amsterdam 1098XGthe Netherlands Department of Materials Science and Engineering The University of SheffieldSheffield S13JDUK

Mechanochemical reactions at the sliding interface between a single-crystalline silicon(Si)wafer and a silica(SiO2)microsphere were studied in three environmental conditions:humid air,potassium chloride(kCl)solution,and kCl solution with an applied voltage.Compared to that from humid air,mechanochemical material removal from the silicon surface increased substantially in the kCl-immersed condition,and further increased when electrochemistry was introduced into the tribological system.By measuring the load dependence of the material removal rate and analyzing the results using a mechanically assisted Arrhenius-type kinetic model,the activation energy(E_(a))and the mechanical energy(E_(m)),by which this energy is reduced by mechanical activation,were compared qualitatively under different environmental conditions.In the kCl-immersed condition,mechanochemistry may decrease the required effective energy of reactions(E_(eff)=E_(a)−E_(m))and promote material removal mainly through improved catalysis of the mechanochemical reactions facilitated by greater availability of water molecules compared to the humid air condition.Thus,the effectiveness of the mechanochemistry is improved.In the electrochemical condition,electrochemically-accelerated oxidation of the silicon surface was confirmed by the X-ray photoelectron spectroscopy(XPS)characterization.The results strongly suggest that electrochemistry further stimulates mechanochemical reactions primarily by increasing the initial energy state of the surface via the facilitated formation of interfacial bonding bridges,i.e.,a surface oxidation/hydroxylation process.

关键词： spherical contact adhesive wear normal loading power law

来源：

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

Distributed Adaptive Resource Allocation:An Uncertain Saddle-Point Dynamics Viewpoint

引用

IEEE/CAA Journal of Automatica Sinica 2023年第12期10卷 2209-2221页

作者： Dongdong Yue Simone Baldi Jinde Cao Qi Li bart De Schutter the School of Mathematics Southeast UniversityNanjing 210096China IEEE the Yonsei Frontier Laboratory Yonsei UniversitySeoul 03722South Korea the School of Automation Southeast UniversityNanjing 210096China the Delft Center for Systems and Control Delft University of TechnologyDelft 2628 CDThe Netherlands

This paper addresses distributed adaptive optimal resource allocation problems over weight-balanced digraphs.By leveraging state-of-the-art adaptive coupling designs for multiagent systems,two adaptive algorithms are proposed,namely a directed-spanning-tree-based algorithm and a node-based algorithm.The benefits of these algorithms are that they require neither sufficiently small or unitary step sizes,nor global knowledge of Laplacian eigenvalues,which are widely required in the literature.It is shown that both algorithms belong to a class of uncertain saddle-point dynamics,which can be tackled by repeatedly adopting the Peter-Paul inequality in the framework of Lyapunov theory.Thanks to this new viewpoint,global asymptotic convergence of both algorithms can be proven in a unified way.The effectiveness of the proposed algorithms is validated through numerical simulations and case studies in IEEE 30-bus and 118-bus power systems.

关键词： Adaptive systems directed graphs resource alloca-tion saddle-point dynamics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：