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Theoretical Discussion on the Relationship between"Shao-yang as the Pivot"and Spine 认领 引用
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作者 Jilin LI Anda WEI Yuanjian ZHONG 《Agricultural Biotechnology》 2026年第3期43-46,共4页
Shaoyang dominates the opening and closing of Yang Qi and the transfusion of Qi,blood and body fluid,and the spine is inseparable from the movement of Yang Qi and the whole body of Qi,blood and body fluid.This article... Shaoyang dominates the opening and closing of Yang Qi and the transfusion of Qi,blood and body fluid,and the spine is inseparable from the movement of Yang Qi and the whole body of Qi,blood and body fluid.This article investigates the impacts of the dysfunctions of Shaoyang Sanjiao pivot and and Shaoyang Gallbladder pivot on the spinal column.Combined with the analysis of clinical medical records,it aims to prove the beauty of using classic theories to guide clinical practice,so as to provide reference for the therapy of spine and spinal related diseases. 展开更多
关键词 "Shaoyang as the pivot" "Spine" Disease
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PNMT:Zero-Resource Machine Translation with Pivot-Based Feature Converter 认领 引用 被引量：1
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作者 Lingfang Li Weijian Hu Mingxing Luo 《Computers, Materials & Continua》 SCIE EI 2025年第9期5915-5935,共21页
Neural machine translation(NMT)has been widely applied to high-resource language pairs,but its dependence on large-scale data results in poor performance in low-resource scenarios.In this paper,we propose a transfer-l... Neural machine translation(NMT)has been widely applied to high-resource language pairs,but its dependence on large-scale data results in poor performance in low-resource scenarios.In this paper,we propose a transfer-learning-based approach called shared space transfer for zero-resource NMT.Our method leverages a pivot pre-trained language model(PLM)to create a shared representation space,which is used in both auxiliary source→pivot(Ms2p)and(Mp2t)translation models.Specifically,we exploit pivot PLM to initialize the Ms2p decoder pivot→targetand Mp2t encoder,while adopting a freezing strategy during the training process.We further propose a feature converter to mitigate representation space deviations by converting the features from the source encoder into the shared representation space.The converter is trained using the synthetic parallel corpus.The final Ms2t model source→targetcombines the Ms2p encoder,feature converter,and Mp2t decoder.We conduct simulation experiments using English as the pivot language for and translations.We finally test our method German→French,German→Czech,Turkish→Hindion a real zero-resource language pair,with Chinese as the pivot language.Experiment results Mongolian→Vietnameseshow that our method achieves high translation quality,with better Translation Error Rate(TER)and BLEU scores compared with other pivot-based methods.The step-wise pre-training with our feature converter outperforms baseline models in terms of COMET scores. 展开更多
关键词 Zero-resource machine translation pivot pre-trained language model transfer learning neural machine translation
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基于Power Pivot的主讲教员资格数据管理研究与实践 认领 引用
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作者 焦贵伟 赵飞 曾倩 《电脑编程技巧与维护》 2025年第6期59-61,153,共3页
为解决主讲教员资格数据管理过程中的课程主讲教员数量和教员主讲课程数量难以快速统计的问题,以陆军炮兵防空兵学院为例,采用一种基于Power Pivot的数据透视表方法,可灵活、快速、准确地掌握学校整体主讲教员资格分布情况,大大提升工... 为解决主讲教员资格数据管理过程中的课程主讲教员数量和教员主讲课程数量难以快速统计的问题,以陆军炮兵防空兵学院为例,采用一种基于Power Pivot的数据透视表方法,可灵活、快速、准确地掌握学校整体主讲教员资格分布情况,大大提升工作效率,为其他院校主讲教员资格数据管理工作提供经验和借鉴。 展开更多
关键词 Power Pivot组件 数据透视表 主讲教员 数据管理
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Novel Annulus-shaped Flexure Pivot in Rotation Application and Dimensionless Design 认领 引用 被引量：7
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作者 BI Shusheng ZHAO Shanshan +2 位作者 SUN Minglei YU Jingjun ZONG Guanghua 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS 2009年第6期800-809,共10页
Large-deflection flexure pivot is widely used in high precision rotation application,but there are less flexure configurations and simple and convenient design methods,This paper presents a novel large-deflection curv... Large-deflection flexure pivot is widely used in high precision rotation application,but there are less flexure configurations and simple and convenient design methods,This paper presents a novel large-deflection curved-compliant annulus-shaped flexure pivot composed of six curved beam flexure elements.It can offer more than lO^angular stroke theoretically.Firstly,main-motion pseudo-rigid-body method is introduced to establish the flexure pivot model.Although pseudo-rigid-body method can be used to analyze the large-deformation flexure pivot performance,the method is definitely a laborious and difficult task for designing this novel flexure pivot.In order to simply the designing process,dimension-design graphs based on the parametric models and finite element analysis is presented.Using the dimension-design method as a tool,the designers can determine the optimal geometry rapidly,based on the stiffness and rotation demands of an annulus-shaped flexure pivot.Finally,dimension-design graph examples are given whose primary design aims to achieve a rotation stroke of annulus-shaped flexure pivot.The finite element analysis results show that the relative designing error between anticipative rotation stroke and graph design result is less than 4%.The dimensionless method used in designing annulus-shaped flexure pivot can reduce design process in both time and complexity.The novel annulus-shaped flexure pivot and dimension-design method are helpful supplement to configuration and design method of large-deflection flexure pivot. 展开更多
关键词 annulus-shaped flexure pivot dimensionless design pseudo-rigid-body model
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Development of center pivot irrigation farmlands from 2009 to 2018 in the Mu Us dune field,China:Implication for land use planning 认领 引用 被引量：4
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作者 LIU Xiaokang DONG Zhibao +4 位作者 DING Yaping LU Ruijie LIU Liyun DING Zhiyong LI Yijing 《Journal of Geographical Sciences》 SCIE CSCD 2022年第10期1956-1968,共13页
The Mu Us dune field in China has become a focal region for research of the prevention and control of desertification.Agricultural practices in this area have been modernized in recent years,evidenced by the developme... The Mu Us dune field in China has become a focal region for research of the prevention and control of desertification.Agricultural practices in this area have been modernized in recent years,evidenced by the development of Center Pivot Irrigation(CPI)farmlands.However,the impacts of CPI farmlands on combating desertification remain poorly understood.This study chose the southeastern part of the Mu Us dune field as a study area to investigate the variations of CPI farmlands from 2009 to 2018 and the influencing factors.The results showed growth trends in both the number and the area of these CPI farmland units over the period.The areas of meso-and micro-scale CPI farmland units stabilized over time to mainly 0-0.2 km2 and 0.2-0.4 km2,respectively;Topography,temperature,and geological substratum were preliminarily identified as the major natural factors driving the development of the CPI farmlands.Within the context of varied stakeholders,the potential for soil erosion,and damage to natural vegetation,the current study suggests that strict management of CPI farmland is required through effective long-term planning and land-use policies.The results of this study can assist in realizing the sustainable development of agriculture and its ecological significance in dune field areas. 展开更多
关键词 center pivot irrigation Mu Us dune field agriculture development desertification land use planning
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The identification of global strategic shipping pivots and their spatial patterns 认领 引用 被引量：9
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作者 王成金 陈沛然 陈云浩 《Journal of Geographical Sciences》 SCIE CSCD 2018年第9期1215-1232,共18页
In concert with developments in global trade and energy resource transportation, there has been a marked increase in reliance on overseas shipping. Unimpeded marine transportation has therefore become a key issue whic... In concert with developments in global trade and energy resource transportation, there has been a marked increase in reliance on overseas shipping. Unimpeded marine transportation has therefore become a key issue which influences national maritime interests including the security of trade and energy resources. A strategic shipping pivot thus performs a vital controlling function for global shipping networks. In this study strategic shipping pivots are defined and subdivided into sea hubs, channels and areas. We then develop a model to identify strategic shipping pivots on a global scale. The results show that, depending on differences in location, function, and type, the concept of strategic shipping pivot permits the identification of both spatial and structural differentiation with respect to strategic hubs, corridors, and seas. Now 44 strategic hubs have formed across the globe. These hubs have become the control centers of local shipping network organization. At the same time, seven strategic corridors containing most shipping routes and transportation capacity connect important sea areas, and permit a high-degree of control over the transport of strategic materials. The strategic seas, the Caribbean, the Mediterranean, Southeast Asia, and the Pacific provide vital import and export pathways, so that the formation of strategic shipping pivots is mainly influenced by factors such as physical geographical conditions, the spatial distribution of socio-economic activities, business organization, technical progress, geopolitical patterns and geopolitical disputes. Physical geographical conditions provide the potential foundations for strategic shipping pivots, while the spatial distribution of socio-economic activities and communications determine the strategic value of these points. Finally, business organization, technical progress, and geopolitical disputes all function to strengthen the strategic mechanisms and the mutagenicity of strategic shipping pivots. 展开更多
关键词 strategic shipping pivot identification model spatial patterns mechanisms of development
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Modeling of Cross-Spring Pivots Subjected to Generalized Planar Loads 认领 引用 被引量：4
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作者 BI Shusheng YAO Yanbin +1 位作者 ZHAO Shanshan YU Jingjun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第6期1075-1085,共11页
Cross-spring pivots, formed by crossing two identical flexural beams at their midpoint, have been broadly used in precision engineering and aerospace fields. Many researches have been conducted on modeling and analysi... Cross-spring pivots, formed by crossing two identical flexural beams at their midpoint, have been broadly used in precision engineering and aerospace fields. Many researches have been conducted on modeling and analysis of cross-spring pivots. However the influence of application position and magnitude of the external loads on the load-rotation and parasitic motion characteristics has not yet been discussed. In order to reveal the effect of the external loads, this paper develops the accurate load-rotation and center shift models of cross-spring pivots, with generalized planar loads applied including bending moment, horizontal and vertical forces. Firstly, by using the energy method, the load-displacement models of the pivot are derived with the assumption of small rotational angles. Based on the models, the influence of generalized planar loads on the load-rotation relationship is discussed, which shows that both application position and magnitude of the vertical and horizontal forces influence the load-rotation behaviors. Then the accurate center shift expressions of the pivot with generalized planar loads are developed, which shows that the rotational angle is the dominant term for both components of the center shift while the vertical and horizontal forces are small. Finally, the accuracy of the proposed model is validated by finite element analysis（FEA）. Comparing the model data with the results obtained from FEA, the relative error of the load-rotation is less than 6% even if the rotational angle reaches 20°; the relative errors of the two components of center shift are less than 5% and 10% respectively when the rotational angle reaches 10°. The proposed model and analytical conclusions can be used to analyze and preliminarily design the compliant mechanisms containing cross-spring pivots. 展开更多
关键词 cross-spring pivot load-rotation behaviors center shift generalized planar loads
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Frequency domain wave equation forward modeling using gaussian elimination with static pivoting 认领 引用 被引量：3
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作者 Song Jian-Yong Zheng Xiao-Dong +3 位作者 Zhang Yan Xu Ji-Xiang Qin Zhen Song Xue-Juan 《Applied Geophysics》 SCIE CSCD 2011年第1期60-68,95,共9页
Frequency domain wave equation forward modeling is a problem of solving large scale linear sparse systems which is often subject to the limits of computational efficiency and memory storage.Conventional Gaussian elimi... Frequency domain wave equation forward modeling is a problem of solving large scale linear sparse systems which is often subject to the limits of computational efficiency and memory storage.Conventional Gaussian elimination cannot resolve the parallel computation of huge data.Therefore,we use the Gaussian elimination with static pivoting(GESP)method for sparse matrix decomposition and multi-source finite-difference modeling.The GESP method does not only improve the computational efficiency but also benefit the distributed parallel computation of matrix decomposition within a single frequency point.We test the proposed method using the classic Marmousi model.Both the single-frequency wave field and time domain seismic section show that the proposed method improves the simulation accuracy and computational efficiency and saves and makes full use of memory.This method can lay the basis for waveform inversion. 展开更多
关键词 Gaussian elimination with static pivoting frequency-domain wave equation forward modeling single-frequency distributed parallel
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Posture Control of Legged Locomotion Based on Virtual Pivot Point Concept 认领 引用 被引量：2
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作者 Hao Sun Junjie Yang +1 位作者 Yinghao Jia Changhong Wang 《Journal of Bionic Engineering》 SCIE EI CSCD 2023年第6期2683-2702,共20页
This paper presents a novel control approach for achieving robust posture control in legged locomotion,specifically for SLIP-like bipedal running and quadrupedal bounding with trunk stabilization.The approach is based... This paper presents a novel control approach for achieving robust posture control in legged locomotion,specifically for SLIP-like bipedal running and quadrupedal bounding with trunk stabilization.The approach is based on the virtual pendulum concept observed in human and animal locomotion experiments,which redirects ground reaction forces to a virtual support point called the Virtual Pivot Point(VPP)during the stance phase.Using the hybrid averaging theorem,we prove the upright posture stability of bipedal running with a fixed VPP position and propose a VPP angle feedback controller for online VPP adjustment to improve performance and convergence speed.Additionally,we present the first application of the VPP concept to quadrupedal posture control and design a VPP position feedback control law to enhance robustness in quadrupedal bounding.We evaluate the effectiveness of the proposed VPP-based controllers through various simulations,demonstrating their effectiveness in posture control of both bipedal running and quadrupedal bounding.The performance of the VPP-based control approach is further validated through experimental validation on a quadruped robot,SCIT Dog,for stable bounding motion generation at different forward speeds. 展开更多
关键词 Legged robots Bionic control Virtual pivot point Posture stability Dynamic locomotion
BLOCK PIVOT METHODS FOR SOLVING FRICTIONAL CONTACT PROBLEMS 认领 引用 被引量：2
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作者 陈万吉 陈国庆 冯恩民 《Acta Mechanica Sinica》 SCIE EI CAS 1995年第1期51-58,共8页
Based on elementary group theory, the block pivot methods for solving two-dimensional elastic frictional contact problems are presented in this paper. It is proved that the algorithms converge within a finite number o... Based on elementary group theory, the block pivot methods for solving two-dimensional elastic frictional contact problems are presented in this paper. It is proved that the algorithms converge within a finite number of steps when the friction coefficient is ''relative small''. Unlike most mathematical programming methods for contact problems, the block pivot methods permit multiple exchanges of basic and nonbasic variables. 展开更多
关键词 ELASTIC FRICTIONAL CONTACT TRIAL AND ERROR METHOD MATHEMATICAL PROGRAMMING METHOD BLOCK PIVOT METHOD CONVERGENCE
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Spatial pattern of global submarine cable network and identification of strategic pivot and strategic channel 认领 引用 被引量：4
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作者 XIE Yongshun WANG Chengjin 《Journal of Geographical Sciences》 SCIE CSCD 2023年第4期719-740,共22页
As a kind of large-scale connectivity infrastructure,submarine cables play a vital role in international telecommunication,socio-economic development and national defense security.However,the current understanding abo... As a kind of large-scale connectivity infrastructure,submarine cables play a vital role in international telecommunication,socio-economic development and national defense security.However,the current understanding about the spatial pattern of global submarine cable network is relatively limited.In this article,we analyze the spatial distribution and connectivity pattern of global submarine cables,and identify their strategic pivots and strategic channels.The main conclusions are as follows:(1)The spatial distribution of global submarine cables is significantly unbalanced,which is characterized by the facts that the distribution of submarine cable lines is similar to that of sea lanes,and the agglomerations of landing stations are distributed unevenly along the coastline.(2)The connectivity pattern of global submarine cable network has a significant scale effect.At the micro,meso and macro scales,the connectivity structure presents chain model,cluster model and hub-and-spoke model,respectively.(3)The distribution of strategic pivots and strategic channels shows a pyramidal hierarchical feature.Singapore ranks highest among all the strategic pivots,while the Gulf of Aden and the Strait of Malacca rank highest among the strategic channels.Based on the identification of strategic pivots and channels,six strategic regions have been divided,which face various network security risks and need special attention and vigilance. 展开更多
关键词 submarine cable network spatial pattern strategic pivot strategic channel global scale
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MEDTRONIC Open Pivot主动脉瓣机械瓣置换术后早中期临床结果 认领 引用 被引量：1
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作者 龚嘉淼 侯剑峰 林宏远 《中国循环杂志》 CSCD 北大核心 2021年第7期700-704,共5页
目的:回顾性分析MEDTRONIC Open Pivot主动脉瓣机械瓣置换术后早中期临床结果。方法:连续收集2016年1月至2019年12月在中国医学科学院阜外医院使用MEDTRONIC Open Pivot主动脉瓣机械瓣行瓣膜置换术的患者348例,回顾性分析患者的基线临... 目的:回顾性分析MEDTRONIC Open Pivot主动脉瓣机械瓣置换术后早中期临床结果。方法:连续收集2016年1月至2019年12月在中国医学科学院阜外医院使用MEDTRONIC Open Pivot主动脉瓣机械瓣行瓣膜置换术的患者348例,回顾性分析患者的基线临床资料、手术结果、早中期生存率和并发症发生情况。结果:348例患者中,男性283例(81.3%),平均年龄(49.4±11.2)岁。围术期无患者死亡和二次手术。共333例(95.7%)患者完成随访,平均随访(1.9±0.8)年(最长3.36年,共计627人年)。随访期间,11例(3.3%)患者死亡,术后第1、2、3、4年分别死亡3例、2例、5例、1例;5例死于心力衰竭,1例死因为人工瓣膜功能障碍,1例因脑出血死亡,4例为其他非心脑血管原因死亡。术后1年、2年、3年累积生存率分别为99.0%、98.1%、93.5%。随访期间,14例(4.2%)患者出现人工瓣膜功能障碍,发生率为2.23%/人年;6例(1.8%)患者出现瓣周漏,发生率为0.96%/人年;2例(0.6%)患者因严重瓣周漏需二次接受手术。17例(5.1%)患者发生主要不良事件,其中心肌梗死1例(0.3%),脑出血2例(0.6%),脑栓塞1例(0.3%),其他严重出血事件13例(3.9%)。结论:MEDTRONIC Open Pivot主动脉瓣机械瓣有效、耐用,置换术后死亡率及并发症发生率低,是主动脉瓣膜置换的可靠选择之一。 展开更多
关键词 MEDTRONIC Open Pivot主动脉瓣机械瓣 主动脉瓣置换 早中期 临床结果
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Effects of water application uniformity using a center pivot on winter wheat yield, water and nitrogen use efficiency in the North China Plain 认领 引用 被引量：8
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作者 CAI Dong-yu YAN Hai-jun LI Lian-hao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第9期2326-2339,共14页
In recent years, the use of fertigation technology with center pivot irrigation systems has increased rapidly in the North China Plain (NCP). The combined effects of water and nitrogen application uniformity on the gr... In recent years, the use of fertigation technology with center pivot irrigation systems has increased rapidly in the North China Plain (NCP). The combined effects of water and nitrogen application uniformity on the grain yield, water use efficiency (WUE) and nitrogen use efficiency (NUE) have become a research hotspot. In this study, a two-year field experiment was conducted during the winter wheat growing season in 2016–2018 to evaluate the water application uniformity of a center pivot with two low pressure sprinklers (the R3000 sprinklers were installed in the first span, the corresponding treatment was RS;the D3000 sprinklers were installed in the second span, the corresponding treatment was DS) and a P85A impact sprinkler as the end gun (the corresponding treatment was EG), and to analyze its effects on grain yield, WUE and NUE. The results showed that the water application uniformity coefficients of R3000, D3000 and P85A along the radial direction of the pivot (CUH) were 87.5, 79.5 and 65%, respectively. While the uniformity coefficients along the traveling direction of the pivot (CUC) were all higher than 85%. The effects of water application uniformity of the R3000 and D3000 sprinklers on grain yield were not significant (P>0.05);however, the average grain yield of EG was significantly lower (P<0.05) than those of RS and DS, by 9.4 and 11.1% during two growing seasons, respectively. The coefficients of variation (CV) of the grain yield had a negative correlation with the uniformity coefficient. The CV of WUE was more strongly affected by the water application uniformity, compared with the WUE value, among the three treatments. The NUE of RS was higher than those of DS and EG by about 6.1 and 4.8%, respectively, but there were no significant differences in NUE among the three treatments during the two growing seasons. Although the CUH of the D3000 sprinklers was lower than that of the R3000, it had only limited effects on the grain yield, WUE and NUE. However, the cost of D3000 sprinklers is lower than that of R3000 sprinklers. Therefore, the D3000 sprinklers are recommended for winter wheat irrigation and fertigation in the NCP. 展开更多
关键词 center pivot low pressure sprinkler water application uniformity winter wheat water and nitrogen use efficiency
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Vibration characteristics of rotor system with tilting-pad journal bearing of elastic and damped pivots 认领 引用 被引量：3
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作者 刘思涌 肖忠会 +1 位作者 闫志勇 陈朱杰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期134-140,共7页
In view of an entire dynamic model of tilting-pad journal bearing(TPJB) in which the pads swing and vibrate along geometric direction of preload, a TPJB of elastic and damped pivots was designed and manufactured. Vibr... In view of an entire dynamic model of tilting-pad journal bearing(TPJB) in which the pads swing and vibrate along geometric direction of preload, a TPJB of elastic and damped pivots was designed and manufactured. Vibration experiments were carried out under the conditions of different rotor bending stiffness and oil supply pressure to find out the relationship between the new bearing's vibration depression effect and other dynamic parameters of the rotor. The result shows that critical amplitudes can be efficaciously reduced while system's stability can be remarkably improved by this bearing. Besides, the bearing's effect of vibration depression weakens as the rotor bending stiffness increases, but heightens it as the oil supply pressure increases. 展开更多
关键词 tilting-pad journal bearing of elastic and damped pivots elastic shims damping stiffness oil supply pressure
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基于Pivot模型的无比钢结构体系地震反应简化分析 认领 引用 被引量：1
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作者 王祥 肖亚明 《结构工程师》 北大核心 2017年第2期96-102,共7页
无比钢结构体系是一种新型的钢结构体系,该结构体系主要由小型桁架等基本单元组成,构造复杂。其墙体由于构件繁多,在有限元分析时十分不便。在借鉴等代拉杆简化模型的基础上,用SAP2000中的Pivot连接单元代替拉杆,进行墙体的简化分析,用... 无比钢结构体系是一种新型的钢结构体系,该结构体系主要由小型桁架等基本单元组成,构造复杂。其墙体由于构件繁多,在有限元分析时十分不便。在借鉴等代拉杆简化模型的基础上,用SAP2000中的Pivot连接单元代替拉杆,进行墙体的简化分析,用一个无比钢结构实例进行对比,表明该简化方法在无比刚结构体系的弹性和弹塑性地震反应分析中的可行性。 展开更多
关键词 无比刚 Pivot模型 恢复力曲线 地震分析 简化分析
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Analysis on pivot turning of quadruped robot with bionic flexible body driven by the PAMs 认领 引用 被引量：1
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作者 雷静桃 Yu Huangying Wu Zhizheng 《High Technology Letters》 EI CAS 2014年第3期288-294,共7页
The pivot turning function of quadruped bionic robots can improve their mobility in unstructured environment.A kind of bionic flexible body mechanism for quadruped robot was proposed in this paper,which is composed of... The pivot turning function of quadruped bionic robots can improve their mobility in unstructured environment.A kind of bionic flexible body mechanism for quadruped robot was proposed in this paper,which is composed of one bionic spine and four pneumatic artificial muscles(PAMs).The coordinated movement of the bionic flexible body and the leg mechanism can achieve pivot turning gait.First,the pivot turning gait planning of quadruped robot was analyzed,and the coordinated movement sequence chart of pivot turning was presented.Then the kinematics modeling of leg side swing and body bending for pivot turning was derived,which should meet the condition of the coordinated movement between bionic flexible body and leg mechanism.The PAM experiment was conducted to analyze its contraction characteristic.The study on pivot turning of the quadruped robot will lay a theoretical foundation for the further research on dynamic walking stability of the quadruped robot in unstructured environment. 展开更多
关键词 quadruped robot bionic flexible body pivot turning pneumatic artificial muscle （PAM）
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Direct linear discriminant analysis based on column pivoting QR decomposition and economic SVD 认领 引用
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作者 胡长晖 路小波 +1 位作者 杜一君 陈伍军 《Journal of Southeast University(English Edition)》 EI CAS 2013年第4期395-399,共5页
A direct linear discriminant analysis algorithm based on economic singular value decomposition （DLDA/ESVD） is proposed to address the computationally complex problem of the conventional DLDA algorithm, which directl... A direct linear discriminant analysis algorithm based on economic singular value decomposition （DLDA/ESVD） is proposed to address the computationally complex problem of the conventional DLDA algorithm, which directly uses ESVD to reduce dimension and extract eigenvectors corresponding to nonzero eigenvalues. Then a DLDA algorithm based on column pivoting orthogonal triangular （QR） decomposition and ESVD （DLDA/QR-ESVD） is proposed to improve the performance of the DLDA/ESVD algorithm by processing a high-dimensional low rank matrix, which uses column pivoting QR decomposition to reduce dimension and ESVD to extract eigenvectors corresponding to nonzero eigenvalues. The experimental results on ORL, FERET and YALE face databases show that the proposed two algorithms can achieve almost the same performance and outperform the conventional DLDA algorithm in terms of computational complexity and training time. In addition, the experimental results on random data matrices show that the DLDA/QR-ESVD algorithm achieves better performance than the DLDA/ESVD algorithm by processing high-dimensional low rank matrices. 展开更多
关键词 direct linear discriminant analysis column pivoting orthogonal triangular decomposition economic singular value decomposition dimension reduction feature extraction
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Development of a Portable Electro-Mechanical Educational Model for Variable Rate Center Pivot Irrigation Technology 认领 引用
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作者 Young J. Han Ahmad Khalilian +1 位作者 Jose Payero Nicholas Rogers 《Journal of Water Resource and Protection》 CAS 2016年第4期449-458,共10页
Center pivot irrigation systems usually apply a relatively uniform amount of water to fields that are often inherently variable, which could lead to significant waste of water and energy. To address this issue, our te... Center pivot irrigation systems usually apply a relatively uniform amount of water to fields that are often inherently variable, which could lead to significant waste of water and energy. To address this issue, our team is now developing an Intelligent Center Pivot (ICP) by integrating sensor-based irrigation scheduling with variable rate irrigation technology. However, before this technology can be applied in commercial production, it is necessary to educate growers about its practicality and potential benefits. The objective of this study was to develop a portable tabletop intelligent center pivot model (ICPDemo) to demonstrate and promote adoption of the ICP technology. This paper describes an ICPDemo constructed in 2014, including the design specifications, electro-mechanical design, control strategy, and performance. The ICPDemo has performed according to design specifications and is successfully being used to demonstrate the benefits and effectiveness of ICP technology for irrigation scheduling. 展开更多
关键词 Irrigation Center Pivot Irrigation Electro-Mechanical Model Sensors Control Variable Rate Irrigation
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一种改进Ball Pivoting的散乱点云数据重建算法 认领 引用 被引量：9
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作者 胡丝兰 周明全 +1 位作者 税午阳 武仲科 《系统仿真学报》 CAS CSCD 北大核心 2015年第10期2446-2452,共7页
Ball Pivoting算法主要是用来对点云数据进行表面重建,算法是从一个种子三角形开始的,球沿着这个种子三角形的一个边进行旋转,直到这个球接触到下一个点,该边与该点组成一个三角形。该算法主要的缺点是当点云数据不均匀的时候球在滚动... Ball Pivoting算法主要是用来对点云数据进行表面重建,算法是从一个种子三角形开始的,球沿着这个种子三角形的一个边进行旋转,直到这个球接触到下一个点,该边与该点组成一个三角形。该算法主要的缺点是当点云数据不均匀的时候球在滚动的过程当中不会接触到点,因此会产生洞。提出了一种对散乱点云数据进行重建的改进的Ball Pivoting算法;对初始点云数据构建k-d树,使得搜索区域算法时间效率提高;使用可变半径搜索改进算法,使得算法能够处理不均匀的点云数据而不会产生洞;优化了网格的拓扑结构。实验结果证明该算法相对于Ball Pivoting算法效率高,且不会生成洞,三角网格的拓扑结构好。 展开更多
关键词 Ball Pivoting三角化 三角网格 散乱点云数据 k-d树
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New Optimal Pivot Rule for the Simplex Algorithm 认领 引用
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作者 Jean Bosco Etoa Etoa 《Advances in Pure Mathematics》 2016年第10期647-658,共12页
The purpose of this paper is to introduce a new pivot rule of the simplex algorithm. The simplex algorithm first presented by George B. Dantzig, is a widely used method for solving a linear programming problem (LP). O... The purpose of this paper is to introduce a new pivot rule of the simplex algorithm. The simplex algorithm first presented by George B. Dantzig, is a widely used method for solving a linear programming problem (LP). One of the important steps of the simplex algorithm is applying an appropriate pivot rule to select the basis-entering variable corresponding to the maximum reduced cost. Unfortunately, this pivot rule not only can lead to a critical cycling (solved by Bland’s rules), but does not improve efficiently the objective function. Our new pivot rule 1) solves the cycling problem in the original Dantzig’s simplex pivot rule, and 2) leads to an optimal improvement of the objective function at each iteration. The new pivot rule can lead to the optimal solution of LP with a lower number of iterations. In a maximization problem, Dantzig’s pivot rule selects a basis-entering variable corresponding to the most positive reduced cost;in some problems, it is well-known that Dantzig’s pivot rule, before reaching the optimal solution, may visit a large number of extreme points. Our goal is to improve the simplex algorithm so that the number of extreme points to visit is reduced;we propose an optimal improvement in the objective value per unit step of the basis-entering variable. In this paper, we propose a pivot rule that can reduce the number of such iterations over the Dantzig’s pivot rule and prevent cycling in the simplex algorithm. The idea is to have the maximum improvement in the objective value function: from the set of basis-entering variables with positive reduced cost, the efficient basis-entering variable corresponds to an optimal improvement of the objective function. Using computational complexity arguments and some examples, we prove that our optimal pivot rule is very effective and solves the cycling problem in LP. We test and compare the efficiency of this new pivot rule with Dantzig’s original pivot rule and the simplex algorithm in MATLAB environment. 展开更多
关键词 Linear Programming Simplex Algorithm Pivot Rules Optimal Pivot Rule
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