期刊文献+
共找到7,916篇文章
< 1 2 250 >
每页显示 20 50 100
The generalized Chapman-Richards function and applications to tree and stand growth 被引量:10
1
作者 刘兆刚 李凤日 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第1期19-26,共8页
The generalized Chapman-Richards model was derived from the Chapman-Richards function in which parameters h, k and m were unconstrained. Based on the structure of solutions and biological interpretations, the model co... The generalized Chapman-Richards model was derived from the Chapman-Richards function in which parameters h, k and m were unconstrained. Based on the structure of solutions and biological interpretations, the model could be classified into eight cases (three categories) at all and among them only 4 kinds of cases are suitable in forestry that represent four typical growth patterns of trees and stands. For each of 4 equations, the model properties and biological interpretations for parameters were discussed in detail. The generalized Chapman-Richards model was capable of describing a wide range of growth curves that was asymptotic or nonasymptotic, with or without inflection point. In order to illustrate the versatility of the model, it was fitted to a group of data sets concerning the DBH growth of cryptomeria plantations with 4 initial densities and the DBH and height growth of natural Korean pine tree. Comparing the generalized Chapman-Richards function and the Schnute model, it was found that the parameters and expressions of the two models were interchangeable in theory, and the fitting results were explicitly identical in empirical applications. 展开更多
关键词 generalized chapman-richards function Schnute model Growth model Growth pattern Cryptomeria japonica Pinus koraiensis
下载PDF
Evaluation of Generalized Error Function via Fast-Converging Power Series
2
作者 Serdar Beji 《Advances in Pure Mathematics》 2024年第6期495-514,共20页
A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power... A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power series expansion developed in resolving the so-called Grandi’s paradox. Comparisons with accurate tabulated values for well-known cases such as the error function are presented using the expansions truncated at various orders. 展开更多
关键词 generalized Error function Gamma function Grandi’s Paradox Fast-Converging Power Series
下载PDF
Ostrowski’s Type Inequalities for Generalized(h,m)−Preinvex Functions with Its Applications
3
作者 LI Ran LIAN Tie-yan 《Chinese Quarterly Journal of Mathematics》 2024年第3期270-287,共18页
A new concept generalized(h,m)−preinvex function on Yang’s fractal sets is proposed.Some Ostrowski’s type inequalities with two parameters for generalized(h,m)−preinvex function are established,where three local fra... A new concept generalized(h,m)−preinvex function on Yang’s fractal sets is proposed.Some Ostrowski’s type inequalities with two parameters for generalized(h,m)−preinvex function are established,where three local fractional inequalities involving generalized midpoint type,trapezoid type and Simpson type are derived as consequences.Furthermore,as some applications,special means inequalities and numerical quadratures for local fractional integrals are discussed. 展开更多
关键词 generalized(h m)−preinvex function Hermite−Hadamard inequality Ostrowski inequality Simpson inequality
下载PDF
Analysis of Progressively Type-Ⅱ Inverted Generalized Gamma Censored Data and Its Engineering Application
4
作者 Refah Alotaibi Sanku Dey Ahmed Elshahhat 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期459-489,共31页
A novel inverted generalized gamma(IGG)distribution,proposed for data modelling with an upside-down bathtub hazard rate,is considered.In many real-world practical situations,when a researcher wants to conduct a compar... A novel inverted generalized gamma(IGG)distribution,proposed for data modelling with an upside-down bathtub hazard rate,is considered.In many real-world practical situations,when a researcher wants to conduct a comparative study of the life testing of items based on cost and duration of testing,censoring strategies are frequently used.From this point of view,in the presence of censored data compiled from the most well-known progressively Type-Ⅱ censoring technique,this study examines different parameters of the IGG distribution.From a classical point of view,the likelihood and product of spacing estimation methods are considered.Observed Fisher information and the deltamethod are used to obtain the approximate confidence intervals for any unknown parametric function of the suggestedmodel.In the Bayesian paradigm,the same traditional inferential approaches are used to estimate all unknown subjects.Markov-Chain with Monte-Carlo steps are considered to approximate all Bayes’findings.Extensive numerical comparisons are presented to examine the performance of the proposed methodologies using various criteria of accuracy.Further,using several optimality criteria,the optimumprogressive censoring design is suggested.To highlight how the proposed estimators can be used in practice and to verify the flexibility of the proposed model,we analyze the failure times of twenty mechanical components of a diesel engine. 展开更多
关键词 Inverted generalized gamma CENSORING spacing function LIKELIHOOD Bayesian optimal plan
下载PDF
Winding Function Model-based Performance Evaluation of a PM Transverse Flux Generator for Applications in Direct-drive Systems
5
作者 Mehrage Ghods Jawad Faiz Ali A Pourmoosa 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第2期216-226,共11页
The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is h... The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3DFEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force(MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magnetomotive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy. 展开更多
关键词 Index Terms—Permanent magnet transverse flux generator Winding function 3D-FEM Cogging torque PROTOTYPING
下载PDF
The Chapman-Richards Distribution and its Relationship to the Generalized Beta
6
作者 Jeffrey H.Gove Thomas B.Lynch Mark J.Ducey 《Forest Ecosystems》 SCIE CSCD 2019年第3期219-235,共17页
Background: The Chapman-Richards distribution is developed as a special case of the equilibrium solution to the McKendrick-Von Foerster equation. The Chapman-Richards distribution incorporates the vital rate assumptio... Background: The Chapman-Richards distribution is developed as a special case of the equilibrium solution to the McKendrick-Von Foerster equation. The Chapman-Richards distribution incorporates the vital rate assumptions of the Chapman-Richards growth function, constant mortality and recruitment into the mathematical form of the distribution. Therefore, unlike 'assumed' distribution models, it is intrinsically linked with the underlying vital rates for the forest area under consideration. Methods: It is shown that the Chapman-Richards distribution can be recast as a subset of the generalized beta distribution of the first kind, a rich family of assumed probability distribution models with known properties. These known properties for the generalized beta are then immediately available for the Chapman-Richards distribution, such as the form of the compatible basal area-size distribution. A simple two-stage procedure is proposed for the estimation of the model parameters and simulation experiments are conducted to validate the procedure for four different possible distribution shapes. Results: The simulations explore the efficacy of the two-stage estimation procedure;these cover the estimation of the growth equation and mortality-recruitment derives from the equilibrium assumption. The parameter estimates are shown to depend on both the sample size and the amount of noise imparted to the synthetic measurements. The results vary somewhat by distribution shape, with the smaller, noisier samples providing less reliable estimates of the vital rates and final distribution forms. Conclusions: The Chapman-Richards distribution in its original form, or recast as a generalized beta form, presents a potentially useful model integrating vital rates and stand diameters into a flexible family of resultant distributions shapes. The data requirements are modest, and parameter estimation is straightforward provided the minimal recommended sample sizes are obtained. 展开更多
关键词 Diameter DISTRIBUTIONS chapman-richards growth generalized BETA DISTRIBUTION of the first KIND Maximum LIKELIHOOD McKendrick-Von Foerster equation Physiologically structured population model Size-structured DISTRIBUTIONS
下载PDF
Generalized Numerical Radius of Real Quaternion Matrices with Symmetric Function
7
作者 夏铁成 张鸿庆 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第3期34-38,共5页
In the paper the generalized numerical radiuses of real quaternion matrices with symmetric function are defined and theirs inequalities are given.
关键词 numerical radius generalized numerical radius symmetric function
下载PDF
The Fourier Transform of a Sort of Generalized Function
8
作者 祝同江 《Journal of Beijing Institute of Technology》 EI CAS 1996年第2期106+101-106,共7页
The Fourier transforms of functions X ln e are given. where λ is a complex constant (λ≠-1,-2. …), a is a complex number. m=0. 1. 2,…,and
关键词 Fourier transform generalized function analytic exextension
下载PDF
Some new exact solutions of Jacobian elliptic function about the generalized Boussinesq equation and Boussinesq-Burgers equation 被引量:9
9
作者 张亮 张立凤 李崇银 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第2期403-410,共8页
By using the modified mapping method, we find some new exact solutions of the generalized Boussinesq equation and the Boussinesq-Burgers equation. The solutions obtained in this paper include Jacobian elliptic functio... By using the modified mapping method, we find some new exact solutions of the generalized Boussinesq equation and the Boussinesq-Burgers equation. The solutions obtained in this paper include Jacobian elliptic function solutions, combined Jacobian elliptic function solutions, soliton solutions, triangular function solutions. 展开更多
关键词 generalized Boussinesq equation Boussinesq-Burgers equation Jacobian elliptic function modified mapping method
下载PDF
MONOTONICITY AND INEQUALITIES FOR THE GENERALIZED DISTORTION FUNCTION 被引量:2
10
作者 马晓艳 褚玉明 王飞 《Acta Mathematica Scientia》 SCIE CSCD 2013年第6期1759-1766,共8页
The authors prove some monotonicity properties of functions involving the generalized Agard distortion function ηg(a,t), and obtain some inequalities for ηk(a, t) and relative distortion functions.
关键词 generalized modular equation generalized η-distortion function monotonic-ity inequality
下载PDF
THE HILBERT BOUNDARY VALUE PROBLEM FOR GENERALIZED ANALYTIC FUNCTIONS IN CLIFFORD ANALYSIS 被引量:2
11
作者 司中伟 杜金元 《Acta Mathematica Scientia》 SCIE CSCD 2013年第2期393-403,共11页
Let R0,n be the real Clifford algebra generated by e1, e2,... , en satisfying eiej+ejei=-2δij,i,j=1,2…,ne0 is the unit element.Let Ω be an open set. A function f is called left generalized analytic in ft if f sati... Let R0,n be the real Clifford algebra generated by e1, e2,... , en satisfying eiej+ejei=-2δij,i,j=1,2…,ne0 is the unit element.Let Ω be an open set. A function f is called left generalized analytic in ft if f satisfies the equation Lf=0,where ……qi 〉0, i =-, 1, - ……, n. In this article, we first give the kernel function for the generalized analytic function. Further, the Hilbert boundary value problem for generalized analytic functions in Rn+1 will be investigated. 展开更多
关键词 generalized analytic function Hilbert boundary value problem H^u function
下载PDF
The New Mixed Generalized Erlang Distribution
12
作者 Therrar Kadri Yara Ghannam 《Applied Mathematics》 2023年第8期497-511,共8页
In probability theory, the mixture distribution M has a density function for the collection of random variables and weighted by w<sub>i</sub> ≥ 0 and . These mixed distributions are used in various discip... In probability theory, the mixture distribution M has a density function for the collection of random variables and weighted by w<sub>i</sub> ≥ 0 and . These mixed distributions are used in various disciplines and aim to enrich the collection distribution to more parameters. A more general mixture is derived by Kadri and Halat, by proving the existence of such mixture by w<sub>i</sub> ∈ R, and maintaining . Kadri and Halat provided many examples and applications for such new mixed distributions. In this paper, we introduce a new mixed distribution of the Generalized Erlang distribution, which is derived from the Hypoexponential distribution. We characterize this new distribution by deriving simply closed expressions for the related functions of the probability density function, cumulative distribution function, moment generating function, reliability function, hazard function, and moments. 展开更多
关键词 generalized Erlang Distribution Mixed Distribution Probability Density function Cumulative Distribution function Moment generating function Hazard Rate function Reliability function Moment of Order k
下载PDF
Improved theory of generalized meteo-ballistic weighting factor functions and their use 被引量:1
13
作者 Vladimir CECH Jiri JEVICKY 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2016年第3期242-254,共13页
It follows from the analysis of artillery fire errors that approximately two-thirds of the inaccuracy of indirect artillery fire is caused by inaccuracies in the determination of the meteo parameters included in fire ... It follows from the analysis of artillery fire errors that approximately two-thirds of the inaccuracy of indirect artillery fire is caused by inaccuracies in the determination of the meteo parameters included in fire error budget model.Trajectories calculated under non-standard conditions are considered to be perturbed.The tools utilized for the analysis of perturbed trajectories are weighting factor functions(WFFs)which are a special kind of sensitivity functions.WFFs are used for calculation of meteo ballistic elements B(ballistic wind w B,densityρB,virtual temperatureτB,pressure p B)as well.We have found that the existing theory of WFF calculation has several significant shortcomings.The aim of the article is to present a new,improved theory of generalized WFFs that eliminates the deficiencies found.Using this theory will improve methods for designing firing tables,fire control systems algorithms,and meteo message generation algorithms. 展开更多
关键词 EXTERIOR BALLISTIC Non-standard projectile trajectory Perturbation Meteoconditions Sensitivity function (generalized) weighting (factor) function(curve) (generalized) EFFECT function Norm EFFECT
下载PDF
Optimization of the Dressing Parameters in Cylindrical Grinding Based on a Generalized Utility Function 被引量:2
14
作者 ALEKSANDROVA Irina 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第1期63-73,共11页
The existing studies, concerning the dressing process, focus on the major influence of the dressing conditions on the grinding response variables. However, the choice of the dressing conditions is often made, based on... The existing studies, concerning the dressing process, focus on the major influence of the dressing conditions on the grinding response variables. However, the choice of the dressing conditions is often made, based on the experience of the qualified staff or using data from reference books. The optimal dressing parameters, which are only valid for the particular methods and dressing and grinding conditions, are also used. The paper presents a methodology for optimization of the dressing parameters in cylindrical grinding. The generalized utility function has been chosen as an optimization parameter. It is a complex indicator determining the economic, dynamic and manufacturing characteristics of the grinding process. The developed methodology is implemented for the dressing of aluminium oxide grinding wheels by using experimental diamond roller dressers with different grit sizes made of medium- and high-strength synthetic diamonds type AC32 and AC80. To solve the optimization problem, a model of the generalized utility function is created which reflects the complex impact of dressing parameters. The model is built based on the results from the conducted complex study and modeling of the grinding wheel lifetime, cutting ability, production rate and cutting forces during grinding. They are closely related to the dressing conditions (dressing speed ratio, radial in-feed of the diamond roller dresser and dress-out time), the diamond roller dresser grit size/grinding wheel grit size ratio, the type of synthetic diamonds and the direction of dressing. Some dressing parameters are determined for which the generalized utility fimction has a maximum and which guarantee an optimum combination of the following: the lifetime and cutting ability of the abrasive wheels, the tangential cutting force magnitude and the production rate of the grinding process. The results obtained prove the possibility of control and optimization of grinding by selecting particular dressing parameters. 展开更多
关键词 dressing conditions cylindrical grinding diamond roller dresser generalized utility function based optimization
下载PDF
Trial function method and exact solutions to the generalized nonlinear Schrdinger equation with time-dependent coefficient 被引量:2
15
作者 曹瑞 张健 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第10期182-185,共4页
In this paper, the trial function method is extended to study the generalized nonlinear Schrodinger equation with time- dependent coefficients. On the basis of a generalized traveling wave transformation and a trial f... In this paper, the trial function method is extended to study the generalized nonlinear Schrodinger equation with time- dependent coefficients. On the basis of a generalized traveling wave transformation and a trial function, we investigate the exact envelope traveling wave solutions of the generalized nonlinear Schrodinger equation with time-dependent coefficients. Taking advantage of solutions to trial function, we successfully obtain exact solutions for the generalized nonlinear Schrodinger equation with time-dependent coefficients under constraint conditions. 展开更多
关键词 generalized nonlinear SchriSdinger equation exact solution trial function method
下载PDF
Generalized thermoelastic functionally graded spherically isotropic solid containing a spherical cavity under thermal shock 被引量:2
16
作者 M.K.Ghosh M.Kanoria 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第10期1263-1278,共16页
This paper is concerned with the determination of thermoelastic displacement, stress and temperature in a functionally graded spherically isotropic infinite elastic medium having a spherical cavity, in the context of ... This paper is concerned with the determination of thermoelastic displacement, stress and temperature in a functionally graded spherically isotropic infinite elastic medium having a spherical cavity, in the context of the linear theory of generalized thermoelasticity with two relaxation time parameters (Green and Lindsay theory). The surface of cavity is stress-free and is subjected to a time-dependent thermal shock. The basic equations have been written in the form of a vector-matrix differential equation in the Laplace transform domain, which is then solved by an eigenvalue approach. Numerical inversion of the transforms is carried out using the Bellman method. Displacement, stress and temperature are computed and presented graphically. It is found that variation in the thermo-physical properties of a material strongly influences the response to loading. A comparative study with a corresponding homogeneous material is also made. 展开更多
关键词 generalized thermoelasticity functionally graded material (FGM) Green-Lindsay theory vector-matrix differential equation Bellman method
下载PDF
Some inequalities for the generalized linear distortion function 被引量:2
17
作者 MA Xiao-yan QIU Song-liang +1 位作者 ZHONG Gen-hong CHU Yu-ming 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2012年第1期87-93,共7页
In this paper, we establish several inequalities for the the generalized linear distortion function λ(a, K) by using the monotonicity and convexity of certain combinations λ(a, K).
关键词 modular equation generalized linear distortion function inequality.
下载PDF
APPROXIMATE CONVEXITY AND CONCAVITY OFGENERALIZED GROTZSCH RING FUNCTION 被引量:2
18
作者 王根娣 裘松良 +1 位作者 张孝惠 褚玉明 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2006年第2期203-206,共4页
In this paper, the so-called approximate convexity and concavity properties of generalized Groetzsch ring function μa (r) by studying the monotonieity,convexity or concavity of certain composites of μa(r) are ob... In this paper, the so-called approximate convexity and concavity properties of generalized Groetzsch ring function μa (r) by studying the monotonieity,convexity or concavity of certain composites of μa(r) are obtained. 展开更多
关键词 generalized Grotzsch ring function Ramanujan's modular equation CONVEXITY concawty.
下载PDF
THIRD-ORDER DIFFERENTIAL SUBORDINATION RESULTS FOR ANALYTIC FUNCTIONS INVOLVING THE GENERALIZED BESSEL FUNCTIONS 被引量:4
19
作者 汤获 Erhan DENIZ 《Acta Mathematica Scientia》 SCIE CSCD 2014年第6期1707-1719,共13页
In the present paper, we derive some third-order differential subordination results for analytic functions in the open unit disk, using the operator Bcκf by means of normalized form of the generalized Bessel function... In the present paper, we derive some third-order differential subordination results for analytic functions in the open unit disk, using the operator Bcκf by means of normalized form of the generalized Bessel functions of the first kind, which is defined as z(Bκ+1^c f(z))′= κBκ^c f(z)-(κ- 1)Bκ+1^c f(z),where b, c, p ∈ C and κ = p +(b + 1)/2 ∈ C / Z0^-(Z0^-= {0,-1,-2, … }). The results are obtained by considering suitable classes of admissible functions. Various known or new special cases of our main results are also pointed out. 展开更多
关键词 differential subordination univalent functions Hadamard product admissible functions generalized Bessel functions
下载PDF
INVARIANT SUBSPACES AND GENERALIZED FUNCTIONAL SEPARABLE SOLUTIONS TO THE TWO-COMPONENT b-FAMILY SYSTEM 被引量:1
20
作者 闫璐 时振华 +1 位作者 王昊 康静 《Acta Mathematica Scientia》 SCIE CSCD 2016年第3期753-764,共12页
Invariant subspace method is exploited to obtain exact solutions of the two- component b-family system. It is shown that the two-component b-family system admits the generalized functional separable solutions. Further... Invariant subspace method is exploited to obtain exact solutions of the two- component b-family system. It is shown that the two-component b-family system admits the generalized functional separable solutions. Furthermore, blow up and behavior of those exact solutions are also investigated. 展开更多
关键词 invariant subspace generalized conditional symmetry generalized functional separable solution Camassa-Holm equation two-component b-family system
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部