期刊文献+
共找到51篇文章
< 1 2 3 >
每页显示 20 50 100
Landslide susceptibility mapping using an integrated model of information value method and logistic regression in the Bailongjiang watershed,Gansu Province,China 被引量:20
1
作者 DU Guo-liang ZHANG Yong-shuang +2 位作者 IQBAL Javed YANG Zhi-hua YAO Xin 《Journal of Mountain Science》 SCIE CSCD 2017年第2期249-268,共20页
Bailongjiang watershed in southern Gansu province, China, is one of the most landslide-prone regions in China, characterized by very high frequency of landslide occurrence. In order to predict the landslide occurrence... Bailongjiang watershed in southern Gansu province, China, is one of the most landslide-prone regions in China, characterized by very high frequency of landslide occurrence. In order to predict the landslide occurrence, a comprehensive map of landslide susceptibility is required which may be significantly helpful in reducing loss of property and human life. In this study, an integrated model of information value method and logistic regression is proposed by using their merits at maximum and overcoming their weaknesses, which may enhance precision and accuracy of landslide susceptibility assessment. A detailed and reliable landslide inventory with 1587 landslides was prepared and randomly divided into two groups,(i) training dataset and(ii) testing dataset. Eight distinct landslide conditioning factors including lithology, slope gradient, aspect, elevation, distance to drainages,distance to faults, distance to roads and vegetation coverage were selected for landslide susceptibility mapping. The produced landslide susceptibility maps were validated by the success rate and prediction rate curves. The validation results show that the success rate and the prediction rate of the integrated model are 81.7 % and 84.6 %, respectively, which indicate that the proposed integrated method is reliable to produce an accurate landslide susceptibility map and the results may be used for landslides management and mitigation. 展开更多
关键词 Landslide susceptibility Integrated model Information value method Logistic regression Bailongjiang watershed
下载PDF
THE QUASI-BOUNDARY VALUE METHOD FOR IDENTIFYING THE INITIAL VALUE OF THE SPACE-TIME FRACTIONAL DIFFUSION EQUATION 被引量:3
2
作者 Fan YANG Yan ZHANG +1 位作者 Xiao LIU Xiaoxiao LI 《Acta Mathematica Scientia》 SCIE CSCD 2020年第3期641-658,共18页
In this article,we consider to solve the inverse initial value problem for an inhomogeneous space-time fractional diffusion equation.This problem is ill-posed and the quasi-boundary value method is proposed to deal wi... In this article,we consider to solve the inverse initial value problem for an inhomogeneous space-time fractional diffusion equation.This problem is ill-posed and the quasi-boundary value method is proposed to deal with this inverse problem and obtain the series expression of the regularized solution for the inverse initial value problem.We prove the error estimates between the regularization solution and the exact solution by using an a priori regularization parameter and an a posteriori regularization parameter choice rule.Some numerical results in one-dimensional case and two-dimensional case show that our method is efficient and stable. 展开更多
关键词 Space-time fractional diffusion equation Ill-posed problem quasi-boundary value method identifying the initial value
下载PDF
The Akp-Btk value method and the resultsfor the retrieval of the parameters of the Earth's free core nutation 被引量:1
3
作者 雷湘鄂 贾民育 李辉 《Acta Seismologica Sinica(English Edition)》 CSCD 2000年第3期342-350,358,共10页
The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free... The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free Core Nutation (FCN),from the Earth's liquid core resonance of gravity tide waves on the diurnal frequency band. Since 1987, some scientists in many different countries have come to calculate the parameters of FCN by using the observational data of gravity tide waves on the diumal frequency band. They basically followed the Stacking method, which needed five diurnal waves for the resolution. In this paper, authors introduced the Aky-Btk value method with clearly geometrical meaning as a new method, which only requires three very high signal-noise-ratio waves o1, K1 and P1 for the resolution. Authors chose the observational data of the three superconducting gravimeter stations respectively located in Cantley of Canada, Wuhan of China and Brussels of Belgium, to compute the parameters of FCN. It was the first time that the observational results of the parameters of FCN obtained from gravitational tide were in accord with the parameters of FCN gained from VLBI since 1987. 展开更多
关键词 Earth's liquid core resonance of gravity tide (LCR) parameters of Earth's free core nutation triangle of LCR Akp-Btk value method
下载PDF
Application of Earned Value Method in Project Cost Management and Schedule Management
4
作者 Wenjing Xu 《Proceedings of Business and Economic Studies》 2021年第4期146-152,共7页
At present,with the rapid development of China's economy,the development of the construction industry has made a new breakthrough.Project management requires the construction industry to continuously play its role... At present,with the rapid development of China's economy,the development of the construction industry has made a new breakthrough.Project management requires the construction industry to continuously play its role and value in improving the ability of project management.Earned value method,which is an important way in the field of project management,enables whole project management to rise to a new height.The specific principle of earned value method will be elaborated by fully introducing the specific role of earned value method in engineering projects to provide a reference and basis for practitioners to improve their management ability. 展开更多
关键词 Earned value method Engineering project Cost management
下载PDF
Analysis of Perioperative Respiratory Care Methods and their Application Value in Children with Congenital Heart Disease
5
作者 Liangyin Quan 《Journal of Clinical and Nursing Research》 2024年第2期22-27,共6页
Objective:To analyze the perioperative respiratory care methods and application value in children with congenital heart disease.Methods:60 children with congenital heart disease(treated from January 2021 to October 20... Objective:To analyze the perioperative respiratory care methods and application value in children with congenital heart disease.Methods:60 children with congenital heart disease(treated from January 2021 to October 2023)were screened and divided into two groups randomly.Each group consisted of 30 cases.The perioperative routine was used in the control group.The observation group underwent the perioperative routine along with better respiratory care.Oxygenation indicators,surgical complications,and family satisfaction levels of the groups were compared.Results:There was no significant difference in the oxygenation index between the two groups of children at admission(P>0.05).At discharge,the oxygenation indicators in the observation group were better than those of the control group,and the incidence of surgical complications was lower than that of the control group.The total satisfaction of family members in the observation group was higher than that of the control group(P<0.05).Conclusion:During the perioperative period for children with congenital heart disease,the implementation of respiratory care,which mainly involves symptomatic care,catheter care,sputum suction care,etc.,can actively improve the oxygenation indicators,reduce surgical complications,and promote faster and better recovery,of children with congenital heart disease. 展开更多
关键词 Congenital heart disease Perioperative respiratory care Nursing methods and value
下载PDF
SOLVING NONLINEAR DELAY-DIFFERENTIAL-ALGEBRAIC EQUATIONS WITH SINGULAR PERTURBATION VIA BLOCK BOUNDARY VALUE METHODS
6
作者 Xiaoqiang Yan Xu Qian +2 位作者 Hong Zhang Songhe Song Xiujun Cheng 《Journal of Computational Mathematics》 SCIE CSCD 2023年第4期643-662,共20页
Block boundary value methods(BBVMs)are extended in this paper to obtain the numerical solutions of nonlinear delay-differential-algebraic equations with singular perturbation(DDAESP).It is proved that the extended BBV... Block boundary value methods(BBVMs)are extended in this paper to obtain the numerical solutions of nonlinear delay-differential-algebraic equations with singular perturbation(DDAESP).It is proved that the extended BBVMs in some suitable conditions are globally stable and can obtain a unique exact solution of the DDAESP.Besides,whenever the classic Lipschitz conditions are satisfied,the extended BBVMs are preconsistent and pth order consistent.Moreover,through some numerical examples,the correctness of the theoretical results and computational validity of the extended BBVMs is further confirmed. 展开更多
关键词 Nonlinear delay-diferential-algebraic equations with singular perturbation Block boundary value methods Unique solvability CONVERGENCE Global stability
原文传递
Fourth Order Compact Boundary Value Method for Option Pricing with Jumps 被引量:1
7
作者 Spike T.Lee Hai-Wei Sun 《Advances in Applied Mathematics and Mechanics》 SCIE 2009年第6期845-861,共17页
We consider pricing options in a jump-diffusion model which requires solving a partial integro-differential equation.Discretizing the spatial direction with a fourth order compact scheme leads to a linear system of or... We consider pricing options in a jump-diffusion model which requires solving a partial integro-differential equation.Discretizing the spatial direction with a fourth order compact scheme leads to a linear system of ordinary differential equations.For the temporal direction,we utilize the favorable boundary value methods owing to their advantageous stability properties.In addition,the resulting large sparse system can be solved rapidly by the GMRES method with a circulant Strang-type preconditioner.Numerical results demonstrate the high order accuracy of our scheme and the efficiency of the preconditioned GMRES method. 展开更多
关键词 Partial integro-differential equation fourth order compact scheme boundary value method PRECONDITIONING Toeplitz matrix
原文传递
A SMALLEST SINGULAR VALUE METHOD FOR SOLVING INVERSE EIGENVALUE PROBLEMS 被引量:1
8
作者 S.F. Xu(Department of Mathematics, Peking University, Beijing) 《Journal of Computational Mathematics》 SCIE CSCD 1996年第1期23-31,共9页
Utilizing the properties of the smallest singular value of a matrix, we propose a new, efficient and reliable algorithm for solving nonsymmetric matrix inverse eigenvalue problems, and compare it with a known method. ... Utilizing the properties of the smallest singular value of a matrix, we propose a new, efficient and reliable algorithm for solving nonsymmetric matrix inverse eigenvalue problems, and compare it with a known method. We also present numerical experiments which illustrate our results. 展开更多
关键词 MATH A SMALLEST SINGULAR value method FOR SOLVING INVERSE EIGENvalue PROBLEMS
原文传递
ESSENTIALLY SYMPLECTIC BOUNDARY VALUE METHODS FOR LINEAR HAMILTONIAN SYSTEMS 被引量:1
9
作者 L. Brugnano(Diprtimento di Enerpetica, University di Firenze, 50134 Firenze, Italy) 《Journal of Computational Mathematics》 SCIE CSCD 1997年第3期233-252,共20页
In this paper we are concerned with finite difference schemes for the numerical approximation of linear Hamiltonian systems of ODEs. Numerical methods which preserves the qualitative properties of Hamiltonian flows ar... In this paper we are concerned with finite difference schemes for the numerical approximation of linear Hamiltonian systems of ODEs. Numerical methods which preserves the qualitative properties of Hamiltonian flows are called symplectic intoprators. Several symplectic methods are known in the class of Runge-Kutta methods. However, no higll order symplectic integrators are known in the class of Linear Multistep Methods (LMMs). Here, by using LMMs as Boundary Value Methods (BVMs), we show that symplectic integrators of arbitrary high order are also available in this class. Moreover, these methods can be used to solve both initial and boundary value problems. In both cases, the properties of the flow of Hamiltonian systems are 'essentially' maintained by the discrete map, at least for linear problems. 展开更多
关键词 MATH ESSENTIALLY SYMPLECTIC BOUNDARY value methodS FOR LINEAR HAMILTONIAN SYSTEMS
原文传递
BOUNDARY VALUE METHODS FOR CA PUTO FR ACTIONAL DIFFERENTIAL EQUATIONS
10
作者 Yongtao Zhou Chengiian Zhang Huiru Wang 《Journal of Computational Mathematics》 SCIE CSCD 2021年第1期108-129,共22页
This paper deals with the numerical computation and analysis for Caputo fractional differential equations(CFDEs).By combining the p-order boundary value methods(B-VMs)and the m-th Lagrange interpolation,a type of exte... This paper deals with the numerical computation and analysis for Caputo fractional differential equations(CFDEs).By combining the p-order boundary value methods(B-VMs)and the m-th Lagrange interpolation,a type of extended BVMs for the CFDEs with y-order(0<r<1)Caputo derivatives are derived.The local stability,unique solvability and convergence of the methods are studied.It is proved under the suitable conditions that the convergence order of the numerical solutions can arrive at min{p,m-γ+1}.In the end,by performing several numerical examples,the computational efficiency,accuracy and comparability of the methods are further ilustrated. 展开更多
关键词 Fractional differential equations Caputo derivatives Boundary value methods Local stability Unique solvability Convergence.
原文传递
Accuracy Assignment Study of Tank Fire Control System Based on Value Analysis Method
11
作者 窦丽华 张佳 陈杰 《Journal of Beijing Institute of Technology》 EI CAS 2006年第4期411-415,共5页
A method of accuracy assignment based on value analysis method (VAM) in tank fire control system (TFCS) is proposed. From the analysis of primary error sources and their error transfer relationships, the mathemati... A method of accuracy assignment based on value analysis method (VAM) in tank fire control system (TFCS) is proposed. From the analysis of primary error sources and their error transfer relationships, the mathematical model is built on the basis of VAM to solve the accuracy assignment problem. Simulation results show the validation and feasibility of the proposed method. It can help designer of tank fire control system work out an optimal system more efficiently and more economically. 展开更多
关键词 tank fire control system(TFCS) accuracy assignment value analysis method(VAM)
下载PDF
PROBLEMS AND METHODS IN MATRIX VALUED RATIONAL INTERPOLATION
12
作者 Gu Chuanqing(Dept.of Math.,Shanghai University,Shanghai 200436,PRC) 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2000年第S1期44-48,共5页
A variety of matrix rational interpolation problems include the partial realizationproblem for matrix power series and the minimal rational interpolation problem for generalmatrix functions.Several problems in circuit... A variety of matrix rational interpolation problems include the partial realizationproblem for matrix power series and the minimal rational interpolation problem for generalmatrix functions.Several problems in circuit theory and digital filter design can also be re-duced to the solution of matrix rational interpolation problems[1—4].By means of thereachability and the observability indices of defined pairs of matrices,Antoulas,Ball,Kang and Willems solved the minimal matrix rational interpolation problem in[1].On 展开更多
关键词 REAL PROBLEMS AND methodS IN MATRIX valueD RATIONAL INTERPOLATION BALL MATH In
下载PDF
Estimation of Acute Toxicity of Ammonium Sulphate to the Fresh Water Catfish,Heteropneustes fossilis——Ⅰ.Analysis of LC_(50) Values Determined by Various Methods
13
作者 TARUNK.BANERJEE 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1993年第1期31-36,共6页
The acute toxic effects of ammonium sulphate to fresh-water catfish, Heteropneustes fossilis (H.fossilis) have been studied by determining LC50 values with 95% confidence limits, by the graphic method, the logistic me... The acute toxic effects of ammonium sulphate to fresh-water catfish, Heteropneustes fossilis (H.fossilis) have been studied by determining LC50 values with 95% confidence limits, by the graphic method, the logistic method, the Spearman and Karber method and the trimmed Spearman-Karber method. The trimmed Spearman-Karber method was found the most ideal for ammonium salt toxicity test. The flaws in the trimmed Spearman-Karber method are also discussed. 展开更多
关键词 values Determined by Various methods Analysis of LC Estimation of Acute Toxicity of Ammonium Sulphate to the Fresh Water Catfish Heteropneustes fossilis
下载PDF
Comparison of K_(IC) Values for SiC Whisker Reinforced Ceramic Composites Obtained by Using Various Methods
14
作者 Tingquan LEI Guangyong LIN +1 位作者 Shuangxi WANG and Yu ZHOU (Dept. of Metals and Technology, Harbin Institute of Technology, Harbin, 150001, China)(To whom correspondence should be addressed) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1994年第5期331-340,共10页
The fracture toughness (KIC) values determined by indentation microfracture method (IM ) for SiC whisker reinforced Al2O3 and ZrO2 based composites were calculated with different IM equations and compared with those o... The fracture toughness (KIC) values determined by indentation microfracture method (IM ) for SiC whisker reinforced Al2O3 and ZrO2 based composites were calculated with different IM equations and compared with those obtained by singte edge notched beam (SENB) technique. Experimental results show that the KIC (IM) values calculated with different equations are quite different one from another. For composites without phase transformable components the KIC (IM) and KIC (SENB) values are practically on the same level, but for composites with phase transformable components (partially stabilized zirconia) the KIC (SENB) values are always higher than KIC (IM). This is because that the IM method can not reveal sensitively the toughening effect due to dynamic t-m transformation of ZrO2 as the SENB method does. The accuracy of the IM method depends on the Suitability of the IM equations and was evaluated for the materials used in this investigation. Two new IM equations are suggested with which the KIC (IM ) values can be obtained very close to KIC (SENB) values for composites having phase transformable components. 展开更多
关键词 SiC values for SiC Whisker Reinforced Ceramic Composites Obtained by Using Various methods Comparison of K IC
下载PDF
Assessment of Direct Eco-value of Liangzi Lake
15
作者 封瑛 李兆华 刘化吉 《Agricultural Science & Technology》 CAS 2013年第6期882-885,共4页
[Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environm... [Obective] This study amied to evaluate the direct usage value of Liangzi Lake, like plants and animal resources and water storage value. [Method] It was measured through the market value method. The physical environment was introduced and the productivity of the lake was investigated both through the literature materials and the investigations. The market value method was clarified in this paper as well as its operation process and the application fields. [Result] Based on the introduction of the current situation in Liangzi Lake, the direct usage value was estimated as 1.32 billion Yuan/year. Plant resources value was 318 million Yuan/year; animal resources value was 675 million Yuan/year; and water storage value was 325 million Yuan/year for the three parts. [Conclusion] This paper will attract more attention to the emphasis of the reasonable development of nature sources. 展开更多
关键词 Valuation assessment Direct usage value Market value method Liangzi Lake
下载PDF
Research on the Coupled and Coordinated Development of Tourism and Transport in Chengdu City
16
作者 Min Kang Qiguang Lv 《Proceedings of Business and Economic Studies》 2024年第3期6-15,共10页
Based on a total of 16 indicators selected from the tourism and transport industries,an evaluation index system of the coupling and coordination development level of tourism and transport is constructed.The entropy va... Based on a total of 16 indicators selected from the tourism and transport industries,an evaluation index system of the coupling and coordination development level of tourism and transport is constructed.The entropy value method and the coupling coordination degree model are used to conduct an empirical study on the development level and coupling coordination level of the transport and tourism industries in Chengdu City from 2011 to 2020.The results show that,on the whole,the coupling coordination degree of transport and tourism in Chengdu is poor and has been in a state of mild to moderate dysfunction.The development level of tourism lagged behind the development of transport from 2011 to 2012,and the two were in a state of mild dysfunction.However,from 2013 onwards,the development level of tourism was prioritized over the development level of transport.This shift caused the coupling coordination degree of the two industries to decline sharply to 0.23305 in 2013.The development level of the tourism industry increased again,reaching 0.34206 in 2019,which marked an improvement.Consequently,the coordination degree of the transport and tourism industries evolved from moderate dislocation to mild dislocation.Finally,the results of the empirical research are analyzed,and corresponding suggestions are put forward to promote the sustainable growth of the transport and tourism industries in Chengdu City.These suggestions aim to improve the coupled and coordinated development level of the two industries. 展开更多
关键词 Coupling coordination Chengdu city Transport industry Tourism industry Entropy value method Coupling coordination degree model
下载PDF
Source location error analysis and optimization methods 被引量:9
17
作者 Maochen Ge 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2012年第1期1-10,共10页
The efficiency of an optimization method for acoustic emission/microseismic(AE/MS) source location is determined by the compatibility of its error definition with the errors contained in the input data.This compatib... The efficiency of an optimization method for acoustic emission/microseismic(AE/MS) source location is determined by the compatibility of its error definition with the errors contained in the input data.This compatibility can be examined in terms of the distribution of station residuals.For an ideal distribution,the input error is held at the station where it takes place as the station residual and the error is not permitted to spread to other stations.A comparison study of two optimization methods,namely the least squares method and the absolute value method,shows that the distribution with this character constrains the input errors and minimizes their impact,which explains the much more robust performance by the absolute value method in dealing with large and isolated input errors.When the errors in the input data are systematic and/or extreme in that the basic data structure is altered by these errors,none of the optimization methods are able to function.The only means to resolve this problem is the early detection and correction of these errors through a data screening process.An efficient data screening process is of primary importance for AE/MS source location.In addition to its critical role in dealing with those systematic and extreme errors,data screening creates a favorable environment for applying optimization methods. 展开更多
关键词 source location RESIDUAL ERROR least squares method absolute value method acoustic emission (AE) microseismic (MS)
下载PDF
A method to calculate design tide levels on the basis of numerical model of tidal current and its application 被引量:3
18
作者 WANG Zhen WEI Youxing ZHANG Changkuan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2012年第4期24-30,共7页
In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tid... In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas. 展开更多
关键词 harbor engineering design tide level numerical model of tidal current correlationanalysis method empirical value method
下载PDF
A New Circulant Preconditioned GMRES Method for Solving Ordinary Differential Equation 被引量:1
19
作者 朱睦正 《Chinese Quarterly Journal of Mathematics》 CSCD 2012年第4期535-544,共10页
The preconditioned generalized minimal residual(GMRES) method is a common method for solving non-symmetric,large and sparse linear systems which originated in discrete ordinary differential equations by Boundary value... The preconditioned generalized minimal residual(GMRES) method is a common method for solving non-symmetric,large and sparse linear systems which originated in discrete ordinary differential equations by Boundary value methods.In this paper,we propose a new circulant preconditioner to speed up the convergence rate of the GMRES method, which is a convex linear combination of P-circulant and Strang-type circulant preconditioners. Theoretical and practical arguments are given to show that this preconditioner is feasible and effective in some cases. 展开更多
关键词 circulant preconditioner boundary value method ordinary differential equation(ODE) GMRES
下载PDF
PHYSICAL VALUE MAPPING ALGORITHM OF MESH IN FINE CAE ANALYSIS OF AUTOMOBILE BODY STRUCTURE 被引量:2
20
作者 Hu Ping Gong Kejia Bao Yidong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2005年第3期338-341,共4页
A physical value mapping (PVM) algorithm based on finite element mesh from the stamped part in stamping process to the product is presented, In order to improve the efficiency of the PVM algorithm, a search way from... A physical value mapping (PVM) algorithm based on finite element mesh from the stamped part in stamping process to the product is presented, In order to improve the efficiency of the PVM algorithm, a search way from the mesh of the product to the mesh of the stamped part will be adopted. At the same time, the search process is divided into two steps: entire search (ES) and local search (LS), which improve the searching efficiency. The searching area is enlarged to avoid missing projection elements in ES process. An arc-length method is introduced in LS process. The validity is confirmed by the results of the complex industry-forming product. 展开更多
关键词 Fine CAE analysis of auto body structure Finite element mesh Arc method Physical value mapping
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部