期刊文献+
共找到147,933篇文章
< 1 2 250 >
每页显示 20 50 100
Blood-letting punctures at twelve Jing-Well points of the hand can treat cerebral ischemia in a similar manner to mannitol 被引量:16
1
作者 Xuan Lu Zelin Chen +4 位作者 Yi Guo Liang Gao Liyuan Jiang Zhongzheng Li Jianqiao Fang 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第6期532-539,共8页
A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of th... A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of the hand, and/or by injecting mannitol into the caudal vein twice daily. Brain tissue was collected at 24, 48 and 72 hours after modeling, and blood was collected through the retinal vein before Evans blue was injected, approximately 1 hour prior to harvesting of brain tissue. Results showed that Evans blue leakage into brain tissue and serum nitric oxide synthase activity were significantly increased in model rats. Treatment with blood-letting punctures at twelve Jing-Well points of the hand and/or injection of mannitol into the caudal vein reduced the amount of Evans blue leakage into the brain tissue and serum nitric oxide synthase activity to varying degrees. There was no significant difference between single treatment and combined treatment. Experimental findings indicate that blood-letting punctures at twelve Jing-Well points of the hand can decrease blood-brain barrier permeability and serum nitric oxide synthase activity in rats following middle cerebral artery occlusion, and its effect is similar to that of mannitol injection alone and Jing-Well points plus mannitol injection. 展开更多
关键词 neural regeneration brain injury jing-well points of hand acupoint blood-letting MANNITOL middlecerebral artery occlusion cerebral ischemia cerebral infarction blood-brain barrier nitric oxidesynthase cerebral edema neuroprotection grants-supported paper neuroregeneration
下载PDF
Bloodletting Puncture at Hand Twelve Jing-Well Points Relieves Brain Edema after Severe Traumatic Brain Injury in Rats via Inhibiting MAPK Signaling Pathway 被引量:3
2
作者 LIU Bao-hu ZHOU Dan +7 位作者 GUO Yi ZHANG Sai GUO Yong-ming GUO Tong-tong CHEN Xu-yi GONG Yi-nan TANG Hui-ling XU Zhi-fang 《Chinese Journal of Integrative Medicine》 SCIE CAS CSCD 2021年第4期291-299,共9页
Objective:To investigate whether blood-brain barrier(BBB)served a key role in the edema-relief effect of bloodletting puncture at hand twelve Jing-well points(HTWP)in traumatic brain injury(TBI)and the potential molec... Objective:To investigate whether blood-brain barrier(BBB)served a key role in the edema-relief effect of bloodletting puncture at hand twelve Jing-well points(HTWP)in traumatic brain injury(TBI)and the potential molecular signaling pathways.Methods:Adult male Sprague-Dawley rats were assigned to the shamoperated(sham),TBI,and bloodletting puncture(bloodletting)groups(n=24 per group)using a randomized number table.The TBI model rats were induced by cortical contusion and then bloodletting puncture were performed at HTWP twice a day for 2 days.The neurological function and cerebral edema were evaluated by modified neurological severity score(mNSS),cerebral water content,magnetic resonance imaging and hematoxylin and eosin staining.Cerebral blood flow was measured by laser speckles.The protein levels of aquaporin 4(AQP4),matrix metalloproteinases 9(MMP9)and mitogen-activated protein kinase pathway(MAPK)signaling were detected by immunofluorescence staining and Western blot.Results:Compared with TBI group,bloodletting puncture improved neurological function at 24 and 48 h,alleviated cerebral edema at 48 h,and reduced the permeability of BBB induced by TBI(all P<0.05).The AQP4 and MMP9 which would disrupt the integrity of BBB were downregulated by bloodletting puncture(P<0.05 or P<0.01).In addition,the extracellular signal-regulated kinase(ERK)and p38 signaling pathways were inhibited by bloodletting puncture(P<0.05).Conclusions:Bloodletting puncture at HTWP might play a significant role in protecting BBB through regulating the expressions of MMP9 and AQP4 as well as corresponding regulatory upstream ERK and p38 signaling pathways.Therefore,bloodletting puncture at HTWP may be a promising therapeutic strategy for TBI-induced cerebral edema. 展开更多
关键词 traumatic brain injury cerebral edema blood brain barrier bloodletting puncture at hand twelve jing-well points mitogen-activated protein kinase pathway Chinese medicine
原文传递
Coexistence of Dirac and Weyl points in non-centrosymmetric semimetal NbIrTe_(4)
3
作者 刘清馨 付阳 +4 位作者 丁鹏飞 马欢 郭朋杰 雷和畅 王善才 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期146-151,共6页
Using angle-resolved photoemission spectroscopy and density functional theory calculations methods,we investigate the electronic structures and topological properties of ternary tellurides NbIrTe_(4),a candidate for t... Using angle-resolved photoemission spectroscopy and density functional theory calculations methods,we investigate the electronic structures and topological properties of ternary tellurides NbIrTe_(4),a candidate for type-II Weyl semimetal.We demonstrate the presence of several Fermi arcs connecting their corresponding Weyl points on both termination surfaces of the topological material.Our analysis reveals the existence of Dirac points,in addition to Weyl points,giving both theoretical and experimental evidences of the coexistence of Dirac and Weyl points in a single material.These findings not only confirm NbIrTe_(4) as a unique topological semimetal but also open avenues for exploring novel electronic devices based on its coexisting Dirac and Weyl fermions. 展开更多
关键词 Fermi arc Weyl point Dirac point angle-resolved photoemission spectroscopy
下载PDF
Exceptional points and quantum dynamics in a non-Hermitian two-qubit system
4
作者 张益玺 张振涛 +2 位作者 杨震山 魏晓志 梁宝龙 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期212-218,共7页
We study the exceptional-point(EP) structure and the associated quantum dynamics in a system consisting of a non-Hermitian qubit and a Hermitian qubit. We find that the system possesses two sets of EPs, which divide t... We study the exceptional-point(EP) structure and the associated quantum dynamics in a system consisting of a non-Hermitian qubit and a Hermitian qubit. We find that the system possesses two sets of EPs, which divide the systemparameter space into PT-symmetry unbroken, partially broken and fully broken regimes, each with distinct quantumdynamics characteristics. Particularly, in the partially broken regime, while the PT-symmetry is generally broken in the whole four-dimensional Hilbert space, it is preserved in a two-dimensional subspace such that the quantum dynamics in the subspace are similar to those in the PT-symmetry unbroken regime. In addition, we reveal that the competition between the inter-qubit coupling and the intra-qubit driving gives rise to a complex pattern in the EP variation with system parameters. 展开更多
关键词 non-Hermitian system exceptional point PT-SYMMETRY
下载PDF
Prediction of collapse process and tipping points for mutualistic and competitive networks with k-core method
5
作者 段东立 毕菲菲 +3 位作者 李思凡 吴成星 吕长春 蔡志强 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期173-180,共8页
Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system... Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system resilience,the consequences would be catastrophic,and eventually lead the ecosystem to complete collapse.We capture the collapse process of ecosystems represented by plant-pollinator networks with the k-core nested structural method,and find that a sufficiently weak interaction strength or a sufficiently large competition weight can cause the structure of the ecosystem to collapse from its smallest k-core towards its largest k-core.Then we give the tipping points of structure and dynamic collapse of the entire system from the one-dimensional dynamic function of the ecosystem.Our work provides an intuitive and precise description of the dynamic process of ecosystem collapse under multiple interactions,and provides theoretical insights into further avoiding the occurrence of ecosystem collapse. 展开更多
关键词 complex networks tipping points dimension reduction k-core
下载PDF
Triple points and phase transitions of D-dimensional dyonic Ad S black holes with quasitopological electromagnetism in Einstein–Gauss–Bonnet gravity
6
作者 牟平辉 蒋青权 +1 位作者 何柯腱 李国平 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期272-287,共16页
By considering the negative cosmological constant Λ as a thermodynamic pressure, we study the thermodynamics and phase transitions of the D-dimensional dyonic Ad S black holes(BHs) with quasitopological electromagnet... By considering the negative cosmological constant Λ as a thermodynamic pressure, we study the thermodynamics and phase transitions of the D-dimensional dyonic Ad S black holes(BHs) with quasitopological electromagnetism in Einstein–Gauss–Bonnet(EGB) gravity. The results indicate that the small/large BH phase transition that is similar to the van der Waals(vdW) liquid/gas phase transition always exists for any spacetime dimensions. Interestingly, we then find that this BH system exhibits a more complex phase structure in 6-dimensional case that is missed in other dimensions.Specifically, it shows for D = 6 that we observed the small/intermediate/large BH phase transitions in a specific parameter region with the triple point naturally appeared. Moreover, when the magnetic charge turned off, we still observed the small/intermediate/large BH phase transitions and triple point only in 6-dimensional spacetime, which is consistent with the previous results. However, for the dyonic Ad S BHs with quasitopological electromagnetism in Einstein–Born–Infeld(EBI) gravity, the novel phase structure composed of two separate coexistence curves observed by Li et al. [Phys. Rev. D105 104048(2022)] disappeared in EGB gravity. This implies that this novel phase structure is closely related to gravity theories, and seems to have nothing to do with the effect of quasitopological electromagnetism. In addition, it is also true that the critical exponents calculated near the critical points possess identical values as mean field theory. Finally, we conclude that these findings shall provide some deep insights into the intriguing thermodynamic properties of the dyonic Ad S BHs with quasitopological electromagnetism in EGB gravity. 展开更多
关键词 AdS black hole phase transition triple point
下载PDF
Petrophysical Evaluation of Cape Three Points Reservoirs
7
作者 Striggner Bedu-Addo Sylvester Kojo Danuor Larry Pax Chegbeleh 《International Journal of Geosciences》 CAS 2024年第2期162-179,共18页
The findings of a study to ascertain and assess the petrophysical characteristics of Cape Three Points reservoirs in the Western basin with a view to describe the reservoir quantitatively using Well Logs, Petrel and T... The findings of a study to ascertain and assess the petrophysical characteristics of Cape Three Points reservoirs in the Western basin with a view to describe the reservoir quantitatively using Well Logs, Petrel and Techlog. The investigated characteristics, which were all deduced from geophysical wire-line logs, include lithology, porosity, permeability, fluid saturation, and net to gross thickness. To characterise the reservoir on the field, a suite of wire-line logs including gamma ray, resistivity, spontaneous potential, and density logs for three wells (WELL_1X, WELL_2X, and WELL_3X) from the Tano Cape Three Point basin were studied. The analyses that were done included lithology delineation, reservoir identification, and petrophysical parameter determination for the identified reservoirs. The tops and bases of the three wells analysed were marked at a depth of 1203.06 - 2015.64 m, 3863.03 - 4253.85 m and 2497.38 - 2560.32 m respectively. There were no hydrocarbons in the reservoirs from the studies. The petrophysical parameters computed for each reservoir provided porosities of 13%, 3% and 11% respectively. The water saturation also determined for these three wells (WELL_1X, WELL_2X and WELL_3X) were 94%, 95% and 89% respectively. These results together with the behaviour of the density and neutron logs suggested that these wells are wildcat wells. 展开更多
关键词 Petrophysical Cape Three points RESERVOIRS
下载PDF
Quantitative determination of the critical points of Mott metal–insulator transition in strongly correlated systems
8
作者 牛月坤 倪煜 +4 位作者 王建利 陈雷鸣 邢晔 宋筠 冯世平 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期647-652,共6页
Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transiti... Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points. 展开更多
关键词 critical point metal–insulator transition local quantum state fidelity strongly correlated system quasiparticle coherent weight
下载PDF
Analysis of the inflection points of height-diameter models
9
作者 Tzeng Yih Lam Mark J.Ducey 《Forest Ecosystems》 SCIE CSCD 2024年第4期414-422,共9页
The inflection point is an important feature of sigmoidal height-diameter(H-D)models.It is often cited as one of the properties favoring sigmoidal model forms.However,there are very few studies analyzing the inflectio... The inflection point is an important feature of sigmoidal height-diameter(H-D)models.It is often cited as one of the properties favoring sigmoidal model forms.However,there are very few studies analyzing the inflection points of H-D models.The goals of this study were to theoretically and empirically examine the behaviors of inflection points of six common H-D models with a regional dataset.The six models were the Wykoff(WYK),Schumacher(SCH),Curtis(CUR),HossfeldⅣ(HOS),von Bertalanffy-Richards(VBR),and Gompertz(GPZ)models.The models were first fitted in their base forms with tree species as random effects and were then expanded to include functional traits and spatial distribution.The distributions of the estimated inflection points were similar between the two-parameter models WYK,SCH,and CUR,but were different between the threeparameter models HOS,VBR,and GPZ.GPZ produced some of the largest inflection points.HOS and VBR produced concave H-D curves without inflection points for 12.7%and 39.7%of the tree species.Evergreen species or decreasing shade tolerance resulted in larger inflection points.The trends in the estimated inflection points of HOS and VBR were entirely opposite across the landscape.Furthermore,HOS could produce concave H-D curves for portions of the landscape.Based on the studied behaviors,the choice between two-parameter models may not matter.We recommend comparing seve ral three-parameter model forms for consistency in estimated inflection points before deciding on one.Believing sigmoidal models to have inflection points does not necessarily mean that they will produce fitted curves with one.Our study highlights the need to integrate analysis of inflection points into modeling H-D relationships. 展开更多
关键词 CONCAVITY Forest inventory and analysis Generalized height-diameter models Growth functions Height-diameter functions Mixed-effects modeling points of inflection Species-specific models
下载PDF
Analysis of the Significance of Key Points of Patient Interventional Psychological Care and Pain Care
10
作者 Xiaoping Dai Chu Luo Jiawei Dai 《Journal of Clinical and Nursing Research》 2024年第3期66-71,共6页
Interventional therapy has become increasingly popular in clinical practice due to advancements in medical technology.However,patients often experience psychological and physiological pressure due to its invasive natu... Interventional therapy has become increasingly popular in clinical practice due to advancements in medical technology.However,patients often experience psychological and physiological pressure due to its invasive nature.The management of patient discomfort and tension is crucial to ensure effective treatment.Psychological and pain management are essential components of interventional therapy,as they significantly impact patient recovery and prognosis.This article discussed the importance of interventional psychological and pain care for patients,starting with the development and spread of interventional therapy.The significance of providing high-quality nursing services to patients and improving their quality of life was also discussed. 展开更多
关键词 Interventional treatment Psychological nursing Pain care Key points Significance analysis
下载PDF
Wake-Promoting Effect of Bloodletting Puncture at Hand Twelve Jing-Well Points in Acute Stroke Patients:A Multi-center Randomized Controlled Trial 被引量:3
11
作者 YU Nan-nan XU Zhi-fang +7 位作者 GAO Yang ZHOU Zhi-liang ZHAO Xue ZHOU Dan WANG Zhen-guo CHEN Ze-lin PAN Xing-fang GUO Yi 《Chinese Journal of Integrative Medicine》 SCIE CAS CSCD 2021年第8期570-577,共8页
Objective To assess the effect and safety of bloodletting puncture at hand twelve Jing-Well points(HTWPs)in acute stroke patients with conscious disturbance.Methods In this multi-center and randomized controlled trial... Objective To assess the effect and safety of bloodletting puncture at hand twelve Jing-Well points(HTWPs)in acute stroke patients with conscious disturbance.Methods In this multi-center and randomized controlled trial,360 patients suffered from ischemic or hemorrhagic stroke with conscious disturbance within 48 h from the onset of symptom were divided into bloodletting(180 cases)and control(180 cases)groups using a block randomization.Patients in both groups received routine Western medicine,and patients in the bloodletting group received additional bloodletting puncture at HTWPs on admission immediately before conventional treatment.The primary outcome measure was Glasgow Coma Scale(GCS)score and the secondary outcomes included blood pressure,respiratory rate and pulse rate.All variables were evaluated at baseline(before bloodletting),0(after bloodletting immediately),15,30,50 and 80 min post bloodletting.Results At 80 min post bloodletting,the proportion of patients with improved consciousness in the bloodletting group was greater than the control group(P<0.05).In the separate analysis of moderate consciousness disturbance subgroup,bloodletting therapy benefited ischemic patients,and improved the eye and language response of GCS score at 15,30,50,80 min post bloodletting(P<0.05 or P<0.01).No significant differences were observed regarding the secondary outcomes between two groups(P>0.05).Conclusion The bloodletting puncture at HTWPs was safe and could improve conscious levels of ischemic stroke patients,highlighting a first-aid intervention for acute stroke. 展开更多
关键词 acute stroke BLOODLETTING jing-well point conscious disturbance randomized controlled trial
原文传递
基于轻量化PointNet网络的林果园喷雾作业靶标实时识别方法 被引量:1
12
作者 刘慧 杜志鹏 +2 位作者 杨锋 张钰 沈跃 《农业工程学报》 EI CAS CSCD 北大核心 2024年第8期144-151,共8页
为了进一步提高喷雾机器人靶标检测的精准性、实时性和应用部署的实用性,该研究提出一种基于轻量化PointNet网络的林果园喷雾作业靶标实时识别方法。首先通过区域提取降采样、地面分割和改进DBSCAN聚类等点云预处理方法提取原始点云中... 为了进一步提高喷雾机器人靶标检测的精准性、实时性和应用部署的实用性,该研究提出一种基于轻量化PointNet网络的林果园喷雾作业靶标实时识别方法。首先通过区域提取降采样、地面分割和改进DBSCAN聚类等点云预处理方法提取原始点云中的靶标;然后通过移动最小二乘上采样将靶标点云转化为满足点云识别网络输入要求的点云数据;最终通过在PointNet网络中引入残差模块和改进循环剪枝算法轻量化PointNet网络,完成林果树靶标的实时识别。试验结果表明,在ModelNet40数据集上,轻量化PointNet网络可达89.7%的准确率;在实际苗圃环境的试验中,该研究方法对靶标的识别准确率可达92.49%,同时误识率与拒识率分别为13.4%和6.47%,相较PointNet网络识别准确率提升了4.38个百分点,误识率和拒识率分别降低了7.2和4.07个百分点;轻量化PointNet网络识别准确率仅比PointNet++网络低1.14个百分点,误识率和拒识率分别高了0.9和1.12个百分点。但是轻量化PointNet网络的模型参数量较PointNet网络和PointNet++网络的模型参数量显著减少,仅为PointNet网络的11.5%,PointNet++网络的27.02%;运算量相较PointNet网络、PointNet++网络分别减少13.3和76.79个百分点。该研究提出的轻量化PointNet网络具有较高的实时性、精确性和鲁棒性,能够满足林果园喷雾作业的靶标识别需求,可为林果园喷雾作业靶标实时识别提供参考。 展开更多
关键词 喷雾 机器人 林果园 点云预处理 轻量化pointNet网络 循环剪枝
下载PDF
Effects of sowing date and ecological points on yield and the temperature and radiation resources of semi-winter wheat 被引量:2
13
作者 ZHANG Zhen-zhen CHENG Shuang +7 位作者 FAN Peng ZHOU Nian-bing XING Zhi-peng HU Ya-jie XU Fang-fu GUO Bao-wei WEI Hai-yan ZHANG Hong-cheng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第5期1366-1380,共15页
Exploring the effects of sowing date and ecological points on the yield of semi-winter wheat is of great significance.This study aims to reveal the effects of sowing date and ecological points on the climate resources... Exploring the effects of sowing date and ecological points on the yield of semi-winter wheat is of great significance.This study aims to reveal the effects of sowing date and ecological points on the climate resources associated with wheat yield in the Rice–Wheat Rotation System.With six sowing dates,the experiments were carried out in Donghai and Jianhu counties,Jiangsu Province,China using two semi-winter wheat varieties as the objects of this study.The basic seedlings of the first sowing date (S1) were planted at 300×10^(4)plants ha^(-1),which was increased by 10%for each of the delayed sowing dates (S2–S6).The results showed that the delay of sowing date decreased the number of days,the effective accumulated temperature and the cumulative solar radiation in the whole growth period.The yields of S1 were higher than those of S2 to S6 by 0.22–0.31,0.5–0.78,0.86–0.98,1.14–1.38,and 1.36–1.59 t ha^(–1),respectively.For a given sowing date,the growth days increased as the ecological point was moved north,while both mean daily temperature and effective accumulative temperature decreased,but the cumulative radiation increased.As a result,the yields at Donghai County were 0.01–0.39 t ha–1lower than those of Jianhu County for the six sowing dates.The effective accumulative temperature and cumulative radiation both had significant positive correlations with yield.The average temperature was significantly negatively correlated with the yield.The decrease in grain yield was mainly due to the declines in grains per spike and 1 000-grain weight caused by the increase in the daily temperature and the decrease in the effective accumulative temperature. 展开更多
关键词 WHEAT YIELD SOWING DATE ECOLOGICAL point
下载PDF
基于PointNet++的邻域特征增强点云语义分割方法
14
作者 李松 张安思 +1 位作者 伍婕 张保 《激光杂志》 CAS 北大核心 2024年第7期174-179,共6页
随着智能驾驶、机器人导航等以点云为基础的应用蓬勃发展,点云语义分割逐渐成为研究热点。然而,现有的点云语义分割方法存在局部特征提取不充分、特征融合不完整的缺陷。针对这些不足,提出了对应的解决方案。对于局部特征提取不充分的现... 随着智能驾驶、机器人导航等以点云为基础的应用蓬勃发展,点云语义分割逐渐成为研究热点。然而,现有的点云语义分割方法存在局部特征提取不充分、特征融合不完整的缺陷。针对这些不足,提出了对应的解决方案。对于局部特征提取不充分的现象,通过嵌入邻域点的坐标、方向、距离等相关信息去关联邻域点的显式特征。对于特征融合不完整的现象,提出了一种最大池化与自注意力池化相结合的混合池化方法。网络架构基于PointNet++,并结合提出的局部特征提取和融合方法,在S3DIS数据集上的实验结果表明,与基线方法PointNet++相比,各评价指标都有不同程度的提高,证实了新方法的有效性和优越性。 展开更多
关键词 三维点云 语义分割 特征提取 深度学习
下载PDF
Traffic prediction enabled dynamic access points switching for energy saving in dense networks 被引量:1
15
作者 Yuchao Zhu Shaowei Wang 《Digital Communications and Networks》 SCIE CSCD 2023年第4期1023-1031,共9页
To meet the ever-increasing traffic demand and enhance the coverage of cellular networks,network densification is one of the crucial paradigms of 5G and beyond mobile networks,which can improve system capacity by depl... To meet the ever-increasing traffic demand and enhance the coverage of cellular networks,network densification is one of the crucial paradigms of 5G and beyond mobile networks,which can improve system capacity by deploying a large number of Access Points(APs)in the service area.However,since the energy consumption of APs generally accounts for a substantial part of the communication system,how to deal with the consequent energy issue is a challenging task for a mobile network with densely deployed APs.In this paper,we propose an intelligent AP switching on/off scheme to reduce the system energy consumption with the prerequisite of guaranteeing the quality of service,where the signaling overhead is also taken into consideration to ensure the stability of the network.First,based on historical traffic data,a long short-term memory method is introduced to predict the future traffic distribution,by which we can roughly determine when the AP switching operation should be triggered;second,we present an efficient three-step AP selection strategy to determine which of the APs would be switched on or off;third,an AP switching scheme with a threshold is proposed to adjust the switching frequency so as to improve the stability of the system.Experiment results indicate that our proposed traffic forecasting method performs well in practical scenarios,where the normalized root mean square error is within 10%.Furthermore,the achieved energy-saving is more than 28% on average with a reasonable outage probability and switching frequency for an area served by 40 APs in a commercial mobile network. 展开更多
关键词 Access points switching on/off ENERGY-SAVING Green network Long short-term memory Traffic prediction
下载PDF
Observation points classifier ensemble for high-dimensional imbalanced classification 被引量:1
16
作者 Yulin He Xu Li +3 位作者 Philippe Fournier‐Viger Joshua Zhexue Huang Mianjie Li Salman Salloum 《CAAI Transactions on Intelligence Technology》 SCIE EI 2023年第2期500-517,共18页
In this paper,an Observation Points Classifier Ensemble(OPCE)algorithm is proposed to deal with High-Dimensional Imbalanced Classification(HDIC)problems based on data processed using the Multi-Dimensional Scaling(MDS)... In this paper,an Observation Points Classifier Ensemble(OPCE)algorithm is proposed to deal with High-Dimensional Imbalanced Classification(HDIC)problems based on data processed using the Multi-Dimensional Scaling(MDS)feature extraction technique.First,dimensionality of the original imbalanced data is reduced using MDS so that distances between any two different samples are preserved as well as possible.Second,a novel OPCE algorithm is applied to classify imbalanced samples by placing optimised observation points in a low-dimensional data space.Third,optimization of the observation point mappings is carried out to obtain a reliable assessment of the unknown samples.Exhaustive experiments have been conducted to evaluate the feasibility,rationality,and effectiveness of the proposed OPCE algorithm using seven benchmark HDIC data sets.Experimental results show that(1)the OPCE algorithm can be trained faster on low-dimensional imbalanced data than on high-dimensional data;(2)the OPCE algorithm can correctly identify samples as the number of optimised observation points is increased;and(3)statistical analysis reveals that OPCE yields better HDIC performances on the selected data sets in comparison with eight other HDIC algorithms.This demonstrates that OPCE is a viable algorithm to deal with HDIC problems. 展开更多
关键词 classifier ensemble feature transformation high-dimensional data classification imbalanced learning observation point mechanism
下载PDF
基于Point Transformer v2的点云枝叶分离方法研究
17
作者 马津 陈一平 +3 位作者 韩汀 王朝磊 张小海 张吴明 《航天返回与遥感》 CSCD 北大核心 2024年第3期62-72,共11页
准确高效的点云枝叶分离对精确计算森林树木的垂直参数至关重要。然而,当前的研究方法计算成本高,且依赖先验知识导致泛化能力不足。针对以上问题,文章提出利用基于点特征的Transformer网络进行自动化的森林场景三维点云的枝叶分离研究... 准确高效的点云枝叶分离对精确计算森林树木的垂直参数至关重要。然而,当前的研究方法计算成本高,且依赖先验知识导致泛化能力不足。针对以上问题,文章提出利用基于点特征的Transformer网络进行自动化的森林场景三维点云的枝叶分离研究。该方法使用Point Transformer v2网络,首先利用网格编码模块提取可学习的局部结构关系,保留点云的几何拓扑结构;其次使用分组注意力实现多通道联合学习,降低特征的冗余度,提高计算的效率;最后构建了基于点的Transformer网络实现高精度森林树木三维点云语义分割,降低了对于先验知识的需求。使用地基激光扫描仪获取的加拿大和芬兰7个不同树种样地的三维点云数据,进行枝叶分离实验和精度评价。实验结果表明,网络整体精度(OA)为94.42%,mIoU为78.89%,能够适应不同树种、不同点云密度的森林场景的枝叶分离。 展开更多
关键词 三维点云 深度学习 枝叶分离 point TRANSFORMER V2
下载PDF
Natural forest ALS-TLS point cloud data registration without control points 被引量:1
18
作者 Jianpeng Zhang Jinliang Wang +3 位作者 Feng Cheng Weifeng Ma Qianwei Liu Guangjie Liu 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第3期809-820,共12页
Airborne laser scanning(ALS)and terrestrial laser scanning(TLS)has attracted attention due to their forest parameter investigation and research applications.ALS is limited to obtaining fi ne structure information belo... Airborne laser scanning(ALS)and terrestrial laser scanning(TLS)has attracted attention due to their forest parameter investigation and research applications.ALS is limited to obtaining fi ne structure information below the forest canopy due to the occlusion of trees in natural forests.In contrast,TLS is unable to gather fi ne structure information about the upper canopy.To address the problem of incomplete acquisition of natural forest point cloud data by ALS and TLS on a single platform,this study proposes data registration without control points.The ALS and TLS original data were cropped according to sample plot size,and the ALS point cloud data was converted into relative coordinates with the center of the cropped data as the origin.The same feature point pairs of the ALS and TLS point cloud data were then selected to register the point cloud data.The initial registered point cloud data was fi nely and optimally registered via the iterative closest point(ICP)algorithm.The results show that the proposed method achieved highprecision registration of ALS and TLS point cloud data from two natural forest plots of Pinus yunnanensis Franch.and Picea asperata Mast.which included diff erent species and environments.An average registration accuracy of 0.06 m and 0.09 m were obtained for P.yunnanensis and P.asperata,respectively. 展开更多
关键词 Airborne laser scanning(ALS) Terrestrial laser scanning(TLS) REGISTRATION Natural forest Iterative closest point(ICP)algorithm
下载PDF
Point Cloud Classification Using Content-Based Transformer via Clustering in Feature Space 被引量:2
19
作者 Yahui Liu Bin Tian +2 位作者 Yisheng Lv Lingxi Li Fei-Yue Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第1期231-239,共9页
Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to est... Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to establish relationships between distant but relevant points. To overcome the limitation of local spatial attention, we propose a point content-based Transformer architecture, called PointConT for short. It exploits the locality of points in the feature space(content-based), which clusters the sampled points with similar features into the same class and computes the self-attention within each class, thus enabling an effective trade-off between capturing long-range dependencies and computational complexity. We further introduce an inception feature aggregator for point cloud classification, which uses parallel structures to aggregate high-frequency and low-frequency information in each branch separately. Extensive experiments show that our PointConT model achieves a remarkable performance on point cloud shape classification. Especially, our method exhibits 90.3% Top-1 accuracy on the hardest setting of ScanObjectN N. Source code of this paper is available at https://github.com/yahuiliu99/PointC onT. 展开更多
关键词 Content-based Transformer deep learning feature aggregator local attention point cloud classification
下载PDF
Material point method simulation of hydro-mechanical behaviour in twophase porous geomaterials: A state-of-the-art review 被引量:2
20
作者 Xiangcou Zheng Shuying Wang +1 位作者 Feng Yang Junsheng Yang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期2341-2350,共10页
The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current stat... The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformation.In this paper,we survey the current state-of-the-art in the MPM simulation of hydro-mechanical behaviour in two-phase porous geomaterials.The review covers the recent advances and developments in the MPM and their extensions to capture the coupled hydro-mechanical problems involving large deformations.The focus of this review is aiming at providing a clear picture of what has or has not been developed or implemented for simulating two-phase coupled large deformation problems,which will provide some direct reference for both practitioners and researchers. 展开更多
关键词 Coupled problems Hydro-mechanical behaviour Large deformation Material point Method(MPM)
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部