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Chebyshev Fitting Way and Error Analysis for Propeller Atlas across Four Quadrants 被引量:20
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作者 LI Dian-pu, WANG Zong-yi, CHI Hai-hong College of Automation , Harbin Engineering University, Harbin 150001, China 《Journal of Marine Science and Application》 2002年第1期52-59,共8页
A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomial fitting results and its error analysis are given. Because it’s difficult generally to get a propel... A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomial fitting results and its error analysis are given. Because it’s difficult generally to get a propeller atlas across four quadrants, a way is used to construct an alternative with higher accuracy based on the properties. As an application example, an alternative for the propeller property of a Deep Submergence Vehicle across four quadrants is given practically and a simulation model of the four quadrants propeller for dynamic condition is set up. The model lays a foundation for DSV full operating-condition movement simulation. A lot of simulation work shows that the results are very close to the practical data and, therefore, are effective. 展开更多
关键词 PROPELLER four quadrants property dynamic simulation ATLAS Chebyshev polynomial DSV alternative property error analysis
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地震勘探仪器在高密度采集中的应用 被引量:12
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作者 夏颖 祝彩霞 孙灵群 《物探装备》 2008年第1期7-10,21,共5页
本文分析了高密度地震采集对地震仪器的基本技术要求,总结了目前几种先进的地震勘探仪器的性能和技术特点,以及国内使用这几种仪器进行高密度勘探的情况。先进的地震勘探仪器是高密度采集获得理想地质目标的基础,文中结合典型高密度采... 本文分析了高密度地震采集对地震仪器的基本技术要求,总结了目前几种先进的地震勘探仪器的性能和技术特点,以及国内使用这几种仪器进行高密度勘探的情况。先进的地震勘探仪器是高密度采集获得理想地质目标的基础,文中结合典型高密度采集项目展示了当今地震勘探仪器在高密度采集中的重要作用。 展开更多
关键词 高密度采集 地震仪器 428XL ARIES SYSTEM four SCORPION
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FLOW PATTERNS AND FORCE CHARACTERISTICS OF LAMINAR FLOW PAST FOUR CYLINDERS IN DIAMOND ARRANGEMENT 被引量:13
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作者 ZOU Lin LIN Yu-feng LU Hong 《Journal of Hydrodynamics》 SCIE EI CSCD 2011年第1期55-64,共10页
A three-dimensional numerical investigation of cross-flow past four circular cylinders in a diamond arrangement at Reynolds number of 200 is carried out.With the spacing ratios(L /D)ranging from 1.2 to 5.0,the flow ... A three-dimensional numerical investigation of cross-flow past four circular cylinders in a diamond arrangement at Reynolds number of 200 is carried out.With the spacing ratios(L /D)ranging from 1.2 to 5.0,the flow patterns can be classified into three basic regimes.The critical spacing ratio for the transition from narrow gap flow pattern to vortex impingement flow pattern around the cylinders is found to beL /D=3.0,while a single bluff-body flow pattern is observed atL /D=1.2.The relationship between the three-dimensional flow patterns and force characteristics around the four cylinders shows that the variation of forces and Strouhal numbers againstL /D are generally governed by these three kinds of flow patterns.It is concluded that the spacing ratio has important effects on the development of the free shear layers about the cylinders and hence has significant effects on the force and pressure characteristics of the four cylinders with different spacing ratios. 展开更多
关键词 four cylinders spacing ratio flow pattern force characteristics
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新型足球教学模式的构建与传统足球教学比较实验研究 被引量:14
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作者 王涛 崔世君 《广州体育学院学报》 北大核心 2015年第5期108-110,121,共4页
采用实验法和问卷调查法等对"三步走"、"四授法"和"五环节"足球教学模式和传统足球教学模式进行了比较研究。结果(1)构建了"三、四、五"足球授课模式;(2)"三、四、五"足球教学模式... 采用实验法和问卷调查法等对"三步走"、"四授法"和"五环节"足球教学模式和传统足球教学模式进行了比较研究。结果(1)构建了"三、四、五"足球授课模式;(2)"三、四、五"足球教学模式下学生专项技术考核成绩和足球课期末总成绩都明显优于传统足球授课模式;(3)"三、四、五"足球教学模式下足球课的强度负荷更加合理,学生体适能指标改善更明显;(4)"三、四、五"足球教学模式活跃了课堂气氛,增强了学生的学习兴趣。提示"三、四、五"足球教学模式是一套可行的、实用的、受欢迎的新型足球授课模式。 展开更多
关键词 足球 “三、四、五”教学模式 传统教学模式
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Therapeutic effect in patients with coronary heart disease based on information analysis from Traditional Chinese Medicine four diagnostic methods 被引量:12
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作者 Yiqin Wang Jin Xu +8 位作者 Rui Guo Chaoxia Xu Yiming Hao Chunfeng Chen Yijian Hong Xiangqun Xiao Wenjie Xu Jing Hong Zhao Lei 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2014年第1期34-41,共8页
OBJECTIVE:To study information gained by Traditional Chinese Medicine(TCM)four diagnostic methods and characteristics of syndrome development before and after treatment in patients with coronary heart disease,and to p... OBJECTIVE:To study information gained by Traditional Chinese Medicine(TCM)four diagnostic methods and characteristics of syndrome development before and after treatment in patients with coronary heart disease,and to probe into assessment indexes of therapeutic effects with distinctive TCM features.METHODS:Information from the four diagnostic methods before and after treatment in 100 patients with coronary heart disease was collected using the TCM interrogation scale,a pulse condition instrument,a tongue-face diagnosis instrument,anda voice diagnosis information collection system.Changes in the four diagnostic method results from before and after treatment were analyzed with frequency analysis and t-test methods.RESULTS:Before treatment,deficiency syndrome complicated with hyperactivity of pathogenic factors was most common.After treatment,deficiency syndrome was most common.This change from complex syndromes to single syndromes indicates disease and syndrome alleviation.Frequencies of symptoms gained by interrogation after treatment for syndrome of deficiency of heart-Qi,syndrome of deficiency of heart-Yin,and turbid phlegm syndrome were all less severe than those before treatment.Parameters of face color,color on all sub-regions of tongue,color of tongue fur,septic and greasy fur,and lip color after treatment all had significant changes.After treatment,part of the voice diagnosis parameters in the deficiency of heart-Yin and turbid phlegm syndromes had significant changes,but no significant changes were found in the deficiency of heart-Qi syndrome.CONCLUSION:Use of the TCM four diagnostic methods can provide an effective basis forTCM syndrome diagnosis,observation of development of state of illness,and evaluation of clinical therapeutic effects. 展开更多
关键词 MEDICINE Chinese traditional four di-agnostic methods SYNDROME Treatment outcome Coronary disease
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Disturbance Observer Based Control for Four Wheel Steering Vehicles With Model Reference 被引量:11
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作者 Shuyou Yu Jing Wang +1 位作者 Yan Wang Hong Chen 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第6期1121-1127,共7页
This paper presents a disturbance observer based control strategy for four wheel steering systems in order to improve vehicle handling stability. By combination of feedforward control and feedback control, the front a... This paper presents a disturbance observer based control strategy for four wheel steering systems in order to improve vehicle handling stability. By combination of feedforward control and feedback control, the front and rear wheel steering angles are controlled simultaneously to follow both the desired sideslip angle and the yaw rate of the reference vehicle model.A nonlinear three degree-of-freedom four wheel steering vehicle model containing lateral, yaw and roll motions is built up, which also takes the dynamic effects of crosswind into consideration.The disturbance observer based control method is provided to cope with ignored nonlinear dynamics and to handle exogenous disturbances. Finally, a simulation experiment is carried out,which shows that the proposed four wheel steering vehicle can guarantee handling stability and present strong robustness against external disturbances. 展开更多
关键词 Disturbance observer based control four wheel steering handling stability model reference.
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Evaluation of the eco-efficiency of four major urban agglomerations in coastal eastern China 被引量:9
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作者 REN Yufei FANG Chuangling +3 位作者 LIN Xueqin SUN Siao LI Guangdong FAN Beili 《Journal of Geographical Sciences》 SCIE CSCD 2019年第8期1315-1330,共16页
Urban agglomerations in China have become the strategic core of national economic development and the main component of the new type of urbanization. However, they are threatened by a series of eco-environmental probl... Urban agglomerations in China have become the strategic core of national economic development and the main component of the new type of urbanization. However, they are threatened by a series of eco-environmental problems and challenges, including the severe overexploitation of natural resources. Eco-efficiency, which is defined as accomplishing the greatest possible economic benefit with the least possible resource input and damage to the environment, is used as an indicator to quantify the sustainability of urban agglomerations. In this work, a traditional data envelopment analysis(DEA) model with a slack-based measurement(SBM) model of undesirable outputs, was used to assess and compare the economic efficiency and eco-efficiency of four major urban agglomerations in eastern China(UAECs) in 2005, 2011, and 2014. The spatio-temporal characteristics of the evolution of urban agglomerations were analyzed. Based on the results of a slack analysis, suggestions for improving the eco-efficiency of the four UAECs are provided. The overall economic efficiency of urban agglomerations located in the Shandong Peninsula, Yangtze River Delta, and Pearl River Delta displayed a V-shaped pattern(decreased and then increased). In contrast, the overall economic efficiency of the Beijing-Tianjin-Hebei urban agglomeration declined during the study period. The Beijing-Tianjin-Hebei urban agglomeration had a considerable loss of economic efficiency due to pollution, whereas the Shandong Peninsula urban agglomeration was less impacted. Overall, the eco-environmental efficiency of the four UAECs declined from 2005 to 2011 and then increased from 2011 to 2014. In addition, the urban eco-efficiency in the four coastal UAECs was characterized by different evolution patterns. The eco-efficiency was higher in the peri-urban areas of the core cities, riverside areas, and seaside areas and lower in the inland cities. The core cities of the Beijing-Tianjin-Hebei, Yangtze River Delta, and Pearl River Delta urban agglomerations were characterized 展开更多
关键词 ECO-EFFICIENCY data envelopment ANALYSIS undesirable SBM SPATIO-TEMPORAL pattern slacks ANALYSIS four urban agglomerations of eastern China
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Chromosomal Constitutions and Reactions to Powdery Mildew and Stripe Rust of Four Novel Wheat-Thinopyrum intermedium Partial Amphiploids 被引量:10
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作者 Yinguang Bao Xia Wu +4 位作者 Chao Zhang Xingfeng Li Fang He Xiaolei Qi Honggang Wang 《Journal of Genetics and Genomics》 SCIE CAS CSCD 2014年第12期663-666,共4页
As a staple food crop for one-third of the world's population, common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) plays an important role in humans' food security. However, the genetic variation of cultivat... As a staple food crop for one-third of the world's population, common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) plays an important role in humans' food security. However, the genetic variation of cultivated wheat has been dramatically narrowed by genetic erosion under the modem cultivation system, resulting in vulnerability to biotic and abiotic stresses (Jiang et al., 1994; Friebe et al., 1996). The wild relatives of wheat represent a large reservoir of superior genes, and transferring these alien genes to modem cultivars through chromosome engineering is a successful method of broadening the genetic diversity of wheat (Chen et al., 2003; 展开更多
关键词 Th TE Chromosomal Constitutions and Reactions to Powdery Mildew and Stripe Rust of four Novel Wheat-Thinopyrum intermedium Partial Amphiploids St
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ESTABLISHMENT OF THE OCEAN DYNAMIC SYSTEM WITH FOUR SUB-SYSTEMS AND THE DERIVATION OF THEIR GOVERNING EQUATION SETS 被引量:8
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作者 YUAN Ye-li QIA0 Fang-li +2 位作者 YIN Xun-qiang HAN Lei LU Ming 《Journal of Hydrodynamics》 SCIE EI CSCD 2012年第2期153-168,共16页
Based on their differences in physical characteristics and time-space scales,the ocean motions have been divided into four types in the present paper:turbulence,wave-like motion,eddy-like motion and circulation.Apply... Based on their differences in physical characteristics and time-space scales,the ocean motions have been divided into four types in the present paper:turbulence,wave-like motion,eddy-like motion and circulation.Applying the three-fold Reynolds averages to the governing equations with Boussinesq approximation,with the averages defined on the former three sub-systems,we derive the governing equation sets of the four sub-systems and refer to their sum as "the ocean dynamic system".In these equation sets,the interactions among different motions appear in two forms:the first one includes advection transport and shear instability generation of larger scale motions,and the second one is the mixing induced by smaller scale motions in the form of transport flux residue.The governing equation sets are the basis of analytical/numerical descriptions of various ocean processes. 展开更多
关键词 ocean dynamic system four sub-systems advection transport shear instability transport flux residue
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Application of Traditional Chinese Medicine Four-diagnostic auxilia-ry apparatus in evaluation of health status and clinical treatment 被引量:8
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作者 Chen Tianyu Niu Tingli +3 位作者 Niu Xin Si Yingchu Yang Xuezhi Ma Liangxiao 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2018年第3期447-451,共5页
OBJECTIVE: To evaluate the application of Traditional Chinese Medicine(TCM) Four-diagnostic Auxiliary Apparatus in disease diagnosis.METHODS: The liver cancer patients and healthy controls were recruited from Shanghai... OBJECTIVE: To evaluate the application of Traditional Chinese Medicine(TCM) Four-diagnostic Auxiliary Apparatus in disease diagnosis.METHODS: The liver cancer patients and healthy controls were recruited from Shanghai Integrated Chinese and Western Medicine Hospital and Beijing University of Traditional Chinese Medicine, respectively. Then, the included subjects were diagnosed by the Four-diagnostic auxiliary apparatus.RESULTS: Thirty liver cancer patients and 30 paired healthy controls were enrolled in this study. Based on the apparatus, the pulse wave velocity was significantly higher in patients compared with controls(P < 0.05). The number of patients with purple tongue and ecchymosis were more than controls(P < 0.05). The number of patients(10%) with yellow tongue coating were higher than the controls(0%). Patients were inclined to be with water type and fire type constitution.CONCLUSION: TCM Four-diagnostic auxiliary apparatus can be applied in clinical diagnosis of body constitution and health status of subjects. It promotes the accuracy and speed for disease diagnosis and TCM standardization. 展开更多
关键词 Liver NEOPLASMS four DIAGNOSTIC meth-ods Equipment and supplies Medicine Chinese traditional MULTI-INFORMATION fusion
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Spatial prediction of landslide susceptibility using GIS-based statistical and machine learning models in Wanzhou County,Three Gorges Reservoir, China 被引量:8
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作者 Ting Xiao Kunlong Yin +1 位作者 Tianlu Yao Shuhao Liu 《Acta Geochimica》 EI CAS CSCD 2019年第5期654-669,共16页
Landslide susceptibility mapping is vital for landslide risk management and urban planning.In this study,we used three statistical models[frequency ratio,certainty factor and index of entropy(IOE)]and a machine learni... Landslide susceptibility mapping is vital for landslide risk management and urban planning.In this study,we used three statistical models[frequency ratio,certainty factor and index of entropy(IOE)]and a machine learning model[random forest(RF)]for landslide susceptibility mapping in Wanzhou County,China.First,a landslide inventory map was prepared using earlier geotechnical investigation reports,aerial images,and field surveys.Then,the redundant factors were excluded from the initial fourteen landslide causal factors via factor correlation analysis.To determine the most effective causal factors,landslide susceptibility evaluations were performed based on four cases with different combinations of factors("cases").In the analysis,465(70%)landslide locations were randomly selected for model training,and 200(30%)landslide locations were selected for verification.The results showed that case 3 produced the best performance for the statistical models and that case 2 produced the best performance for the RF model.Finally,the receiver operating characteristic(ROC)curve was used to verify the accuracy of each model's results for its respective optimal case.The ROC curve analysis showed that the machine learning model performed better than the other three models,and among the three statistical models,the IOE model with weight coefficients was superior. 展开更多
关键词 LANDSLIDE SUSCEPTIBILITY mapping STATISTICAL MODEL Machine learning MODEL four cases
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江西省主要养鸡地区4种鸡免疫抑制病的血清学调查 被引量:9
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作者 康昭风 谢金防 +4 位作者 韦启鹏 谢明贵 武艳平 邹志恒 李思明 《江西农业学报》 CAS 2010年第11期125-127,共3页
对江西省11个地市主要养鸡地区的24个鸡群的460份血清样品用ELISA方法进行了鸡传染性贫血(CIA)、禽网状内皮细胞增生症(RE)、禽呼肠孤病毒感染(ARV)血清抗体的检测,并对其中的368份血清样品用ELISA方法进行了J-亚型禽白血病(ALV-J)血清... 对江西省11个地市主要养鸡地区的24个鸡群的460份血清样品用ELISA方法进行了鸡传染性贫血(CIA)、禽网状内皮细胞增生症(RE)、禽呼肠孤病毒感染(ARV)血清抗体的检测,并对其中的368份血清样品用ELISA方法进行了J-亚型禽白血病(ALV-J)血清抗体的检测,结果CIAV、REV、ALV-J、ARV(ELISA)抗体总阳性率分别为80.65%、21.30%、6.52%、96.30%。结果表明目前江西省各地饲养的鸡群中这4种免疫抑制病的感染相当普遍,而且多为混合感染,感染一种及以上免疫抑制病的个体为99.13%,同时感染两种及以上免疫抑制病的个体为56.96%,同时感染3种及以上免疫抑制病的个体为20.43%,同时感染4种免疫抑制病的个体为2.17%。 展开更多
关键词 江西省 养鸡 地区 种鸡 免疫抑制病 血清学调查 Jiangxi Province four 混合感染 ELISA方法 血清样品 血清抗体 个体 鸡传染性贫血 细胞增生症 ALV-J 禽白血病 结果 检测 鸡群
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Adaptive Modification of the Rolling Force Prediction 被引量:7
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作者 姚小兰 张迪生 +1 位作者 梁启宏 胡浩平 《Journal of Beijing Institute of Technology》 EI CAS 2002年第1期33-36,共4页
In rolling process, the rolling force is an important parameter. The precision of the predicted rolling force will directly affect the precision of the finished product. By using adaptive control theory and fusing the... In rolling process, the rolling force is an important parameter. The precision of the predicted rolling force will directly affect the precision of the finished product. By using adaptive control theory and fusing the measured and predicted data, the precision of the predicted rolling force is gradually improved. This system has been used in plant for more than one year, and the result of the application shows that the system has steady and reliable performance, and high precision. 展开更多
关键词 hot rolling four high mill automatic gauge control bender roller
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A Map Coloring Method
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作者 Shijun Han 《Journal of Applied Mathematics and Physics》 2023年第4期1200-1208,共9页
Different vertices are colored in a plan. Adjacent vertices are colored dif-ferently from nonadjacent vertices, which are colored the same color. One color is used for a single point, two colors are used for points wi... Different vertices are colored in a plan. Adjacent vertices are colored dif-ferently from nonadjacent vertices, which are colored the same color. One color is used for a single point, two colors are used for points without a loop, and a maximum of four colors are used for points with a loop. A maximum of four colors are used to color all points. . 展开更多
关键词 MAP four Colors four Colors Conjecture Graph Theory
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Serum angiotensin-converting enzyme level for evaluating significant fibrosis in chronic hepatitis B 被引量:6
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作者 Ryuichi Noguchi Kosuke Kaji +9 位作者 Tadashi Namisaki Kei Moriya Mitsuteru Kitade Kosuke Takeda Hideto Kawaratani Yasushi Okura Yosuke Aihara Masanori Furukawa Akira Mitoro Hitoshi Yoshiji 《World Journal of Gastroenterology》 SCIE CAS 2017年第36期6705-6714,共10页
AIM To evaluate the diagnostic performance of angiotensinconverting enzyme(ACE)on significant liver fibrosis in patients with chronic hepatitis B(CHB). METHODS In total,100 patients with CHB who underwent liver biopsy... AIM To evaluate the diagnostic performance of angiotensinconverting enzyme(ACE)on significant liver fibrosis in patients with chronic hepatitis B(CHB). METHODS In total,100 patients with CHB who underwent liver biopsy in our hospital were enrolled,and 70 patients except for 30 patients with hypertension,fatty liver or habitual alcoholic consumption were analyzed.We compared histological liver fibrosis and serum ACE levels and evaluated the predictive potential to diagnose significant liver fibrosis by comparison with several biochemical marker-based indexes such as the aspartate aminotransferase(AST)-to-platelet ratio index(APRI),the fibrosis index based on four factors(FIB-4),the Mac-2 binding protein glycosylation isomer(M2BPGi)level and the number of platelets(Plt). RESULTS Serum ACE levels showed moderately positive correlation with liver fibrotic stages(R2=0.181).Patients with significant,advanced fibrosis and cirrhosis(F2-4)had significantly higher serum ACE levels than those with early-stage fibrosis and cirrhosis(F0-1).For significant fibrosis(≥F2),the 12.8 U/L cut-off value of ACE showed 91.7%sensitivity and 75.0%specificity.The receiver-operating characteristic(ROC)curves analysis revealed that the area under the curve(AUC)value of ACE was 0.871,which was higher than that of APRI,FIB-4,M2BPGi and Plt. CONCLUSION The serum ACE level could be a novel noninvasive,easy,accurate,and inexpensive marker of significant fibrosis stage in patients with CHB. 展开更多
关键词 Angiotensin-converting enzyme Hepatitis B virus Liver FIBROSIS Noninvasive FIBROSIS marker ASPARTATE aminotransferase-to-platelet ratio INDEX FIBROSIS INDEX based on four factors Mac-2 binding protein GLYCOSYLATION ISOMER
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The Difference of Capital Input and Productivity in Service Industries: Based on Four Stages Bootstrap-DEA Model 被引量:6
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作者 Wei XI Xiran CHENG 《Journal of Systems Science and Information》 CSCD 2018年第4期320-335,共16页
Based on the concept of productive capital stock, this paper estimated capital input by three asset types of China’s 36 service industries in 2003–2015, and compared with the results of wealth capital stock. This st... Based on the concept of productive capital stock, this paper estimated capital input by three asset types of China’s 36 service industries in 2003–2015, and compared with the results of wealth capital stock. This study found that the wealth capital stock method underestimates the actual capital input in each sector in varying degrees, and it may interference the accuracy of productivity evaluation in sectors. According to the new estimation results of capital input, this paper further applied four stages bootstrap-DEA method to estimate industrial productivity, and calculated its confidence intervals. This study found that, the years of education and the average wage have a significant positive impact on the productivity of service industries; the productive services have a short board effect in the whole service industry. 展开更多
关键词 service industries PRODUCTIVITY productive capital stock wealth capital stock four stages bootstrap-DEA
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Numerical Simulation on Oscillation-Sliding-Uplift Rock Coupled Motion of Caisson Breakwater Under Wave Excitation 被引量:6
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作者 王元战 龚薇 迟丽华 《China Ocean Engineering》 SCIE EI 2010年第2期207-218,共12页
Corresponding to the sliding and the overturning failure,the elementary motion modes of caisson breakwater include the horizontal-rotational oscillation coupled motion,the horizontal sliding-rotational oscillation cou... Corresponding to the sliding and the overturning failure,the elementary motion modes of caisson breakwater include the horizontal-rotational oscillation coupled motion,the horizontal sliding-rotational oscillation coupled motion,the horizontal vibrating-uplift rocking coupled motion,and the horizontal sliding-uplift rocking coupled motion.The motion mode of a caisson will transform from one to another depending on the wave forces and the motion behaviors of the caisson.The numerical models of four motion modes of caisson are developed,and the numerical simulation procedure for joint motion process of various modes of caisson breakwater under wave excitation is presented and tested by a physical model experiment.It is concluded that the simulation procedure is reliable and can be applied to the dynamic stability analysis of caisson breakwaters. 展开更多
关键词 caisson breakwater four motion modes joint motion process numerical simulation
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Estimation of Daily Global Solar Radiation with Different Sunshine-Based Models for Some Burundian Stations
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作者 Mathias Bashahu Gratien Ndacayisaba 《Energy and Power Engineering》 2024年第1期1-20,共20页
Sunshine duration (S) based empirical equations have been employed in this study to estimate the daily global solar radiation on a horizontal surface (G) for six meteorological stations in Burundi. Those equations inc... Sunshine duration (S) based empirical equations have been employed in this study to estimate the daily global solar radiation on a horizontal surface (G) for six meteorological stations in Burundi. Those equations include the Ångström-Prescott linear model and four amongst its derivatives, i.e. logarithmic, exponential, power and quadratic functions. Monthly mean values of daily global solar radiation and sunshine duration data for a period of 20 to 23 years, from the Geographical Institute of Burundi (IGEBU), have been used. For any of the six stations, ten single or double linear regressions have been developed from the above-said five functions, to relate in terms of monthly mean values, the daily clearness index () to each of the next two kinds of relative sunshine duration (RSD): and . In those ratios, G<sub>0</sub>, S<sub>0 </sub>and stand for the extraterrestrial daily solar radiation on a horizontal surface, the day length and the modified day length taking into account the natural site’s horizon, respectively. According to the calculated mean values of the clearness index and the RSD, each station experiences a high number of fairly clear (or partially cloudy) days. Estimated values of the dependent variable (y) in each developed linear regression, have been compared to measured values in terms of the coefficients of correlation (R) and of determination (R<sub>2</sub>), the mean bias error (MBE), the root mean square error (RMSE) and the t-statistics. Mean values of these statistical indicators have been used to rank, according to decreasing performance level, firstly the ten developed equations per station on account of the overall six stations, secondly the six stations on account of the overall ten equations. Nevertheless, the obtained values of those indicators lay in the next ranges for all the developed sixty equations:;;;, with . These results lead to assert that any of the sixty developed linear regressions (and thus equations in terms of and ), fits very adequately measured data, and should 展开更多
关键词 Clearness Index Two Kinds of Relative Sunshine Duration Ångström-Prescott Linear Model and four Derivatives Statistical Tests Six Burundian Stations
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Teaching Reform of “Probability Theory and Mathematical Statistics” Under the Background of New Engineering
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作者 Jianxin Wang 《Journal of Contemporary Educational Research》 2024年第3期32-37,共6页
Probability theory and mathematical statistics are fundamental courses for various majors in science and engineering.In response to the current teaching situation,we should integrate theory with practice,implement tea... Probability theory and mathematical statistics are fundamental courses for various majors in science and engineering.In response to the current teaching situation,we should integrate theory with practice,implement teaching reform,and carry out teaching innovation.The article carries out blended teaching with deep integration of online and offline modes and within and outside of class,constructing innovative measures of“four integrations and four reshaping.”The article conducts diversified evaluations to stimulate learning motivation and help achieve talent cultivation goals.Through the close integration of probability theory and mathematical statistics course teaching with professional education and practical application,the“three-in-one”teaching goal of value shaping,ability cultivation,and knowledge exploration is achieved.The fundamental task of“cultivating morality and talents”is implemented. 展开更多
关键词 four integrations and four reshaping” BOPPPS blended teaching Classified and layered teaching Interdisciplinary integration Full nested evaluation system
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Influence of Waveguide Properties on Wave Prototypes Likely to Accompany the Dynamics of Four-Wave Mixing in Optical Fibers
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作者 Jean Roger Bogning Marcelle Nina Zambo Abou’ou +4 位作者 Christian Regis Ngouo Tchinda Mathurin Fomekong Oriel Loh Ndichia Stallone Mezezem Songna François Béceau Pelap 《Journal of Applied Mathematics and Physics》 2024年第7期2601-2633,共33页
In this article, we study the impacts of nonlinearity and dispersion on signals likely to propagate in the context of the dynamics of four-wave mixing. Thus, we use an indirect resolution technique based on the use of... In this article, we study the impacts of nonlinearity and dispersion on signals likely to propagate in the context of the dynamics of four-wave mixing. Thus, we use an indirect resolution technique based on the use of the iB-function to first decouple the nonlinear partial differential equations that govern the propagation dynamics in this case, and subsequently solve them to propose some prototype solutions. These analytical solutions have been obtained;we check the impact of nonlinearity and dispersion. The interest of this work lies not only in the resolution of the partial differential equations that govern the dynamics of wave propagation in this case since these equations not at all easy to integrate analytically and their analytical solutions are very rare, in other words, we propose analytically the solutions of the nonlinear coupled partial differential equations which govern the dynamics of four-wave mixing in optical fibers. Beyond the physical interest of this work, there is also an appreciable mathematical interest. 展开更多
关键词 Optical Fiber four Waves Mixing Implicit Bogning Function Coupled Nonlinear Partial Differential Equations Nonlinear Coefficient Dispersive Coefficient Waveguide Properties
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