期刊文献+
共找到535,954篇文章
< 1 2 250 >
每页显示 20 50 100
文章速递A New Modification of Newton Method with Cubic Convergence 认领
1
作者 Aurelien Goudjo Louis Kouye 《理论数学进展(英文)》 2021年第1期1-11,共11页
Newton’s method is used to find the roots of a system of equations <span style="white-space:nowrap;"><em>f</em> (x) = 0</span>. It is one of the most important procedures in numerica... Newton’s method is used to find the roots of a system of equations <span style="white-space:nowrap;"><em>f</em> (x) = 0</span>. It is one of the most important procedures in numerical analysis, and its applicability extends to differential equations and integral equations. Analysis of the method shows a quadratic convergence under certain assumptions. For several years, researchers have improved the method by proposing modified Newton methods with salutary efforts. A modification of the Newton’s method was proposed by McDougall and Wotherspoon <a href="#ref1">[1]</a> with an order of convergence of <span style="white-space:nowrap;">1+ <span style="white-space:nowrap;">&#8730;2</span></span>. On a new type of methods with cubic convergence was proposed by H. H. H. Homeier <a href="#ref2">[2]</a>. In this article, we present a new modification of Newton method based on secant method. Analysis of convergence shows that the new method is cubically convergent. Our method requires an evaluation of the function and one of its derivatives. 展开更多
关键词 Newton’s Methods Secant Method Cubic Convergence Iterative Method
在线阅读 下载PDF
文章速递Verification of an Explicitly Coupled Thermal-Phase Field-Mechanical Electromagnetic (TPME) Framework by the Method of Manufactured Solutions 认领
2
作者 Travis S. Ramsay 《建模与仿真(英文)》 2021年第1期1-25,共25页
An explicitly coupled two-dimensional (2D) multiphysics finite element method (FEM) framework comprised of thermal, phase field, mechanical and electromagnetic (TPME) equations was developed to simulate the conversion... An explicitly coupled two-dimensional (2D) multiphysics finite element method (FEM) framework comprised of thermal, phase field, mechanical and electromagnetic (TPME) equations was developed to simulate the conversion of solid kerogen in oil shale to liquid oil through </span><i><span style="font-family:Verdana;font-size:12px;">in-situ</span></i><span style="font-family:Verdana;font-size:12px;"> pyrolysis by radio frequency heating. Radio frequency heating as a method of <i></span><i><span style="font-family:Verdana;font-size:12px;">in-situ</span></i><span style="font-family:Verdana;font-size:12px;"></i> pyrolysis represents a tenable enhanced oil recovery method, whereby an applied electrical potential difference across a target oil shale formation is converted to thermal energy, heating the oil shale and causing it to liquify to become liquid oil. A number of <i></span><i><span style="font-family:Verdana;font-size:12px;">in-situ</span></i><span style="font-family:Verdana;font-size:12px;"></i> pyrolysis methods are reviewed but the focus of this work is on the verification of the TPME numerical framework to model radio frequency heating as a potential dielectric heating process for enhanced oil recovery.</span></span><span style="font-size:10pt;font-family:""> </span><span style="font-family:Verdana;">Very few studies exist which describe production from oil shale;furthermore, there are none that specifically address the verification of numerical models describing radio frequency heating. As a result, the Method of Manufactured Solutions (MMS) was used as an analytical verification method of the developed numerical code. Results show that the multiphysics finite element framework was adequately modeled enabling the simulation of kerogen conversion to oil as a part of the analysis of a TPME numerical model. 展开更多
关键词 Radio Frequency Heating In-Situ Pyrolysis Oil Shale Multiphysics Explicit Coupling Finite Element Method Method of Manufactured Solutions
在线阅读 下载PDF
Analysis of a two-grid method for semiconductor device problem 认领
3
作者 Ying LIU Yanping CHEN +1 位作者 Yunqing HUANG Qingfeng LI 《应用数学和力学:英文版》 SCIE EI 2021年第1期143-158,共16页
The mathematical model of a semiconductor device is governed by a system of quasi-linear partial differential equations.The electric potential equation is approximated by a mixed finite element method,and the concentr... The mathematical model of a semiconductor device is governed by a system of quasi-linear partial differential equations.The electric potential equation is approximated by a mixed finite element method,and the concentration equations are approximated by a standard Galerkin method.We estimate the error of the numerical solutions in the sense of the Lqnorm.To linearize the full discrete scheme of the problem,we present an efficient two-grid method based on the idea of Newton iteration.The main procedures are to solve the small scaled nonlinear equations on the coarse grid and then deal with the linear equations on the fine grid.Error estimation for the two-grid solutions is analyzed in detail.It is shown that this method still achieves asymptotically optimal approximations as long as a mesh size satisfies H=O(h^1/2).Numerical experiments are given to illustrate the efficiency of the two-grid method. 展开更多
关键词 two-grid method semiconductor device mixed finite element method Galerkin method L^q error estimate
在线阅读 下载PDF
A Necessary and Sufficient Condition for the Solvability of the Nonlinear Schr?dinger Equation on a Finite Interval 认领
4
作者 Ruo-meng LI Xian-guo GENG 《应用数学学报:英文版》 SCIE 2021年第1期75-100,共26页
The admissibility of the initial-boundary data,which characterizes the existence of solution for the initial-boundary value problem,is important.Based on the Fokas method and the inverse scattering transformation,an a... The admissibility of the initial-boundary data,which characterizes the existence of solution for the initial-boundary value problem,is important.Based on the Fokas method and the inverse scattering transformation,an approach is developed to solve the initial-boundary value problem of the nonlinear Schrodinger equation on a finite interval.A necessary and sufficient condition for the admissibility of the initial-boundary data is given,and the reconstruction of the potential is obtained. 展开更多
关键词 initial-boundary value problems inverse scattering transform method Fokas method
A New Nonmonotone Trust Region Barzilai-Borwein Method for Unconstrained Optimization Problems 认领
5
作者 Xing LI Wen-li DONG Zheng PENG 《应用数学学报:英文版》 SCIE 2021年第1期166-175,共10页
In this paper,we propose a new nonmonotone trust region Barzilai-Borwein(BB for short)method for solving unconstrained optimization problems.The proposed method is given by a novel combination of a modified Metropolis... In this paper,we propose a new nonmonotone trust region Barzilai-Borwein(BB for short)method for solving unconstrained optimization problems.The proposed method is given by a novel combination of a modified Metropolis criterion,BB-stepsize and trust region method.The new method uses the reciprocal of BB-stepsize to approximate the Hessian matrix of the objective function in the trust region subproblems,and accepts some bad solutions according to the modified Metropolis criterion based on simulated annealing idea.Under some suitable assumptions,the global convergence of the new method is established.Some preliminary numerical results indicate that,the new method is more efficient compared with the existing trust region BB method. 展开更多
关键词 Barzilai-Borwein method trust region method nonmonotone technique Metropolis criterion global convergence
Benchmarking of two three-dimensional numerical models in time/space domain to predict railway-induced ground vibrations 认领
6
作者 Jesus Fernandez-Ruiz Luis E.Medina Rodriguez +1 位作者 Pedro Alves Costa Margarita Martinez-Diaz 《地震工程与工程振动:英文版》 SCIE EI 2021年第1期245-256,共12页
In the last 30 years,the scientific community has developed and proposed different models and numerical approaches for the study of vibrations induced by railway traffic.Most of them are formulated in the frequency/wa... In the last 30 years,the scientific community has developed and proposed different models and numerical approaches for the study of vibrations induced by railway traffic.Most of them are formulated in the frequency/wave number domain and with a 2.5D approach.Three-dimensional numerical models formulated in the time/space domain are less frequently used,mainly due to their high computational cost.Notwithstanding,these models present very attractive characteristics,such as the possibility of considering nonlinear behaviors or the modelling of excess pore pressure and non-homogeneous and non-periodic geometries in the longitudinal direction of the track.In this study,two 3D numerical approaches formulated in the time/space domain are compared and experimentally validated.The first one consists of a finite element approach and the second one of a finite difference approach.The experimental validation in an actual case situated in Carregado(Portugal)shows an acceptable fitting between the numerical results and the actual measurements for both models.However,there are some differences among them.This study therefore includes some recommendations for their use in practical soil dynamics and geotechnical engineering. 展开更多
关键词 railway vibrations time/space domain 3D numerical model finite difference method implicit finite element method
在线阅读 下载PDF
文章速递Non-Cooperative Spectrum Sensing Based on Cyclostationary Model of Digital Signals in the Context of Cognitive Radio 认领
7
作者 Jean-Marie Kadjo Raoule Agoua +2 位作者 Aliou Bamba Adama Konaté Olivier Asseu 《工程(英文)(1947-3931)》 2021年第1期56-70,共15页
This paper addresses the problem of the opportunistic spectrum access in Cognitive Radio. Indeed, most spectrum sensing algorithms suffer from a high computational cost to achieve the detection process. They need a pr... This paper addresses the problem of the opportunistic spectrum access in Cognitive Radio. Indeed, most spectrum sensing algorithms suffer from a high computational cost to achieve the detection process. They need a prior knowledge of signal characteristics and present a bad performance in low Signal to Noise Ratio (SNR) environment. The choice of the optimal detection threshold is another issue for these spectrum sensing algorithms. To overcome the limits of spectrum detectors, we propose in this paper, a blind detection method based on the cyclostationary features of communication signals. Our detector evaluates the level of hidden periodicity contained in the observed signal to make decision on the state of a bandwidth. In order to reduce the computational cost, we take advantage of the FFT Accumulation Method to estimate the cyclic spectrum of the observed signal. Then, we generate the Cyclic Domain Profile of the cyclic spectrum which allows us to evaluate the level of the hidden periodicity in the signal. This level of periodicity is quantified through the crest factor of Cyclic Domain Profile, which represents the decision statistic of the proposed detector. We have established the analytic expression of the optimal threshold of the detection and the probability of detection to evaluate the performance of the proposed detector. Simulation results show that the proposed detector is able to detect the presence of a communication signal on a bandwidth in a very low SNR scenario. 展开更多
关键词 Spectrum Sensing Cyclostaionarity FFT Accumulation Method Cyclic Spectrum Spectrum Coherence Cognitive Radio
在线阅读 下载PDF
文章速递Selection Wind Farm Sites Based on GIS Using a Boolean Method: Evaluation of the Case of Cameroon 认领
8
作者 Fotsing Metegam Isabelle Flora Njomo Donatien +1 位作者 René Tchinda Oumarou Hamandjoda 《电力能源(英文)》 2021年第1期1-24,共24页
The negative effects of traditional methods of electricity generation on the<span style="font-family:;" "=""><span style="font-family:Verdana;"> environment have created ... The negative effects of traditional methods of electricity generation on the<span style="font-family:;" "=""><span style="font-family:Verdana;"> environment have created the need for strategic planning and development of renewable and sustainable energy systems. This paper presents the analysis of the suitability of wind farm sites using a Boolean decision-making approach </span><span style="font-family:Verdana;">based on geographic information system (GIS) modeling. This analysis is </span><span style="font-family:Verdana;">based on different climatic, geographical, economic and environmental criteria such </span><span style="font-family:Verdana;">as wind resource, slope, accessibility by road, proximity to the electricity</span><span style="font-family:Verdana;"> network and optimal distance from airports. The results of the study show that the most favorable sites are mainly located in the northern part of the country, particularly in the Far North and North regions. There are also favorable </span><span style="font-family:Verdana;">sites in the North-West, South-West, West, Littoral and very little in the</span><span style="font-family:Verdana;"> South while the central and eastern regions are not suitable. This is mainly due to the tropical forest that covers the entire region of East Cameroon and the low wind speed in these regions which is the determining factor for the installation of wind farms. The appropriate land for the installation of wind </span><span style="font-family:Verdana;">farms is </span><span style="font-family:Verdana;">approximately 2.56% corresponding to an area of </span></span><span style="font-family:Verdana;">11</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;">602</span><span style="font-family:Verdana;">.494414</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">km<span style="white-space:nowrap;"><sup></sup></span><sup></sup></span><span style="font-family:Verdana;"><sup>2</sup><span style="white-space:nowrap;"></span></span><span style="font-family:Verdana;">. Ho</span><span style="font-family:Verdana;">w</span><span style="font-family:Verdana;">ever, when we include the condition that a wind farm must have at least 4</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">km<sup></sup></span><span style="font-family:Verdana;"><span style="white-space:normal;font-family:Verdana;"><span style="white-space:nowrap;"><sup></sup></span><sup></sup></span><span style="white-space:normal;font-family:Verdana;"><sup>2</sup><span style="white-space:nowrap;"></span></span></span><span style="font-family:Verdana;"> of surface area, is goes from 2.56% to 2.22% (11</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;">602.494414 km<sup></sup></span><span style="font-family:Verdana;"><span style="white-space:normal;font-family:Verdana;"><span style="white-space:nowrap;"><sup></sup></span><sup></sup></span><span style="white-space:normal;font-family:Verdana;"><sup>2</sup><span style="white-space:nowrap;"></span></span></span><span style="font-family:Verdana;"> to</span><span style="font-family:Verdana;"> 10</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;">344.424539 km</span><span style="font-family:Verdana;"><sup></sup></span></span><span style="font-family:Verdana;"><span style="white-space:normal;font-family:Verdana;"><span style="white-space:nowrap;"><sup></sup></span><sup></sup></span><span style="white-space:normal;font-family:Verdana;"><sup>2</sup><span style="white-space:nowrap;"></span></span></span><span style="font-family:Verdana;">);thus a surface reduction of approximately 1258</span><span style="font-family:Verdana;">.</span><span style="font-family:;" "=""><span style="font-family:Verdana;">069875 km</span><span style="font-family:Verdana;"><sup></sup></span></span><span style="font-family:Verdana;"><span style="white-space:normal;font-family:Verdana;"><span style="white-space:nowrap;"><sup></sup></span><sup></sup></span><span style="white-space:normal;font-family:Verdana;"><sup>2</sup><span style="white-space:nowrap;"></span></span></span><span style="font-family:Verdana;">. We can conclude that despite the fact that Cameroon does not have a huge potential for wind energy because of the low wind speed observed in the country, it is still possible to have some favorable sites for the installation of the parks wind. In addition, a study of hybrid solar-wind systems could improve the efficiency of the power plants in Cameroon.</span> 展开更多
关键词 Wind Energy Boolean Method Geographic Information System (GIS) Cameroon Wind Farm
在线阅读 下载PDF
文章速递Women’s Attitudes and Knowledge towards the Use of Contraceptive Methods 认领
9
作者 Emmanuel Gasaba Fiona Niyomana +4 位作者 Felicité Irakoze Edith Baramana Anitha Ndayizeye Ismaël Nicoyishimiye Edouard Niyongabo 《护理学期刊(英文)》 2021年第1期17-27,共11页
<strong>Background:</strong> Contraceptive use reduces the need for abortion by preventing unwanted pregnancies, and the causes of maternal death worldwide. Contraceptive use helps women to plan their preg... <strong>Background:</strong> Contraceptive use reduces the need for abortion by preventing unwanted pregnancies, and the causes of maternal death worldwide. Contraceptive use helps women to plan their pregnancies and contributes for population growth. This study aims to analyze the attitudes and knowledge of the women attending Van Norma Clinic for the use of contraceptive methods. <strong>Methods:</strong> A cross-sectional study was used to analyze the information. A convenience sampling method has been used to select the 100 women who attended Van Norman Clinic in Family planning service in the period of the study of four months (April to July, 2020). A self-administered questionnaire with four parameters addressing importance of using contraceptive methods, the factors affecting the women’s attitudes for not using contraceptive methods, types of contraceptive methods currently used, advantages and disadvantages of using contraceptive methods was used to collect data. <strong>Results:</strong> Research findings show that the majority of respondents knew the importance of using contraceptive methods like preventing unwanted pregnancies (97%), spacing pregnancies (96%), planning pregnancies (92%), and getting well (70%). Two factors affecting women for not using contraceptive methods had been identified such as religion (73%) and fear (70%). In addition, the women attending Van Norman Clinic prefer using implants (99%) and injectable (99%). It is clear that women do not know the consequences related to the nonuse of contraceptive methods. Some recommendations have been made to the health care facilities, parents, women themselves, churches’ leaders and government in general. <strong>Conclusion:</strong> Factors which influence women’s attitudes for not using contraceptive methods were notified in our study such as religion (73.0%) and fear (70.0%) which was explained by the fact that in Burundi most people are catholic which is the most religion prohibiting the use of contraceptive methods. However, the participants’ knowledge was significantly good as their score was more than 50% for all variables. 展开更多
关键词 Contraceptive Method Family Planning Women Attitude Knowledge
在线阅读 下载PDF
文章速递One-Step Multiplex PCR for Simultaneous Detection and Identification of Eight Medically Important <i>Candida</i>Species 认领
10
作者 Akira Fukatsu Osamu Tsuzukibashi +13 位作者 Hidenori Suzuk Katsuhiro Asaka Yoshinori Ono Mana Fuchigami Taira Kobayashi Satoshi Uchibori Yuji Takahashi Chiaki Komine Yoshimi Konishi Yuki Ogura Hiroko Omori Masanobu Wakami Hiroshi Murakami Masahiko Fukumoto 《口腔学期刊(英文)》 2021年第1期14-24,共11页
Recently, the incidence of<span> </span><i><span>Candida</span></i><span> infections has substantially increased. Conventional identification methods for </span><... Recently, the incidence of<span> </span><i><span>Candida</span></i><span> infections has substantially increased. Conventional identification methods for </span><i><span>Candida</span></i><span> species are technically difficult to conduct and cannot accurately distinguish each species. The purpose of the present study was to design primers to identify and detect simultaneously</span><span> </span><span>eight medically important </span><i><span>Candida</span></i><span> species using one-step multiplex PCR. PCR primers were designed based on partial sequences of intergenic spacer (IGS) and internal transcribed spacer (ITS) genes of eight medically important </span><i><span>Candida</span></i><span> species. These primers were able to distinguish each </span><i><span>Candida</span></i><span> species and did not display cross-reactivity with representative </span><i><span>Candida </span></i><span>species other than the eight</span><i><span> Candida</span></i><span> species. Moreover, our developed one-step multiplex PCR method is accurate, specific, cost-effective, time-saving, and worked without requiring DNA extraction.</span> 展开更多
关键词 Candida Candida albicans One-Step Multiplex PCR PCR Method
在线阅读 下载PDF
文章速递Stochastic Model for the Spread of the COVID-19 Virus 认领
11
作者 Majdi Elhiwi 《应用数学(英文)》 2021年第1期24-31,共8页
The COVID-19 pandemic has become a great challenge to scientific, biological and medical research as well as to economic and social sciences. Hence, the objective of infectious disease modeling-based data analysis is ... The COVID-19 pandemic has become a great challenge to scientific, biological and medical research as well as to economic and social sciences. Hence, the objective of infectious disease modeling-based data analysis is to recover these dynamics of infectious disease spread and to estimate parameters that govern these dynamics. The random aspect of epidemics leads to the development of stochastic epidemiological models. We establish a stochastic combined model using numerical scheme Euler, Markov chain and Susceptible-Exposed-Infected-Recovery (SEIR) model. The combined SEIR model was used to predict how epidemics will develop and then to act accordingly. These COVID-19 data were analyzed from several countries such as Italy, Russia, USA and Iran. 展开更多
关键词 Stochastic Model COVID-19 EULER Method SEIR Model Markov Chain
在线阅读 下载PDF
文章速递Homotopy Analysis Method for a Conservative Nonlinear Oscillator with Fractional Power 认领
12
作者 Huaxiong Chen Yanyan Wang 《应用数学与应用物理(英文)》 2021年第1期31-40,共10页
In this paper, the homotopy analysis method is applied to deduce the periodic solutions of a conservative nonlinear oscillator for which the elastic force term is proportional to<em> u</em><sup>1/3&l... In this paper, the homotopy analysis method is applied to deduce the periodic solutions of a conservative nonlinear oscillator for which the elastic force term is proportional to<em> u</em><sup>1/3</sup>. By introducing the auxiliary linear operator and the initial guess of solution, the homotopy analysis solving is set up. By choosing the suitable convergence-control parameter, the accurate high-order approximations of solution and frequency for the whole range of initial amplitudes can easily be obtained. Comparison of the results obtained using this method with those obtained by different methods reveals that the former is more accurate, effective and convenient for these types of nonlinear oscillators. 展开更多
关键词 Homotopy Analysis Method Approximate Solutions Fractional Power Nonlinear Oscillation
在线阅读 下载PDF
文章速递The Kinematics Analysis of Heald Selecting Mechanism of Rotary Electronic Dobby 认领
13
作者 Hongbin Yu Xiangpeng Zhao +1 位作者 Honghuan Yin Hongyu Shao 《应用科学(英文)》 2021年第1期93-102,共10页
In order to improve the reliability of the mechanical movement of the rotary electronic dobby, the kinematics analysis of the heald selection mechanism is carried out and the simulation is carried out with Matlab. Fir... In order to improve the reliability of the mechanical movement of the rotary electronic dobby, the kinematics analysis of the heald selection mechanism is carried out and the simulation is carried out with Matlab. Firstly, the operation mechanism of the heald selection mechanism is analyzed in detail. The conjugate cam is mapped. The cam profile curve is fitted with cubic spline interpolation. Secondly, based on the overall analysis method and the complex vector method, the kinematics analysis of the key components after the high pair low generation is performed, and the angular displacement and angular velocity of each component are calculated with the rotation of the active cam. Finally, the movement curve diagram is drawn with Matlab, which lays the foundation for the dynamic analysis and in-depth study of the selection mechanism in the future. 展开更多
关键词 Heald Selection Mechanism Substitute Equivalent Linkage Instead of Higher Pair Complex Number Vector Method The Kinematics Analysis
在线阅读 下载PDF
文章速递Higher Order Solitary Wave Solutions of the Standard KdV Equations 认领
14
作者 Clovis Taki Djeumen Tchaho Hugues Martial Omanda +2 位作者 Gaston N’tchayi Mbourou Jean Roger Bogning Timoléon Crépin Kofané 《应用科学(英文)》 2021年第1期103-125,共23页
Considered under their standard form, the fifth-order KdV equations are a sort of reading table on which new prototypes of higher order solitary waves residing there, have been uncovered and revealed to broad daylight... Considered under their standard form, the fifth-order KdV equations are a sort of reading table on which new prototypes of higher order solitary waves residing there, have been uncovered and revealed to broad daylight. The mathematical tool that made it possible to explore and analyze this equation is the Bogning-Djeumen Tchaho-Kofané method extended to the new implicit Bogning' functions. The analytical form of the solutions chosen in this manuscript is particular in the sense that it contains within its bosom, a package of solitary waves made up of three solitons, especially, the bright type soliton, the hybrid soliton and the dark type soliton which we estimate capable in their interactions of generating new hybrid or multi-form solitons. Existence conditions of the obtained solitons have been determined. It emerges that, these existence conditions of the chosen ansatz could open the way to other new varieties of fifth-order KdV equations including to which it will be one of the solutions. Some of the obtained solitons are exact solutions. Intense numerical simulations highlighted numerical stability and confirmed the hybrid character of the obtained solutions. These results will help to model new nonlinear wave phenomena, in plasma media and in fluid dynamics, especially, on the shallow water surface. 展开更多
关键词 Standard KdV Equations Bogning-Djeumen Tchaho-Kofané Method Higher Order Solitary Wave Multi-Form Solitons New Implicit Bogning’ Functions
在线阅读 下载PDF
文章速递Parametric and Non-Parametric Survival Analysis of Patients with Acute Myeloid Leukemia (AML) 认领
15
作者 Aditya Chakraborty Chris P. Tsokos 《应用科学(英文)》 2021年第1期126-148,共23页
<strong>Background:</strong> Acute Myeloid leukemia (AML) is the most prominent acute leukemia in adults. In the United States, we experience over 20,000 cases per year. Over the past decade, improvements ... <strong>Background:</strong> Acute Myeloid leukemia (AML) is the most prominent acute leukemia in adults. In the United States, we experience over 20,000 cases per year. Over the past decade, improvements in the diagnosis of subtypes of AML and advances in therapeutic approaches have improved the outlook for patients with AML. However, despite these advancements, the survival rate among patients who are less than 65 years of age is only 40 percent. <strong>Purpose:</strong> The purpose of the paper is to study if there exists any significant difference in the survival probabilities of male and female AML patients. Also, we want to investigate if there is any parametric probability distribution that best fits the male and female patient survival and compare the survival probabilities with the non-parametric Kaplan-Meier (KM) method. <strong>Methods:</strong> We used both parametric and non-parametric statistical methods to perform the survival analysis to assess the survival probabilities of 2015 patients diagnosed with AML.<strong> Results:</strong> We found evidence of a statistically significant difference between the mean survival time of male and female patients diagnosed with AML. We performed parametric survival analysis and found a Generalized Extreme Value (GEV) distribution best fitting the data of the survival time for male and female patients. We then estimated the survival probabilities and compared them with the frequently used non-parametric Kaplan-Meier (KM) survival method. <strong>Conclusion:</strong> The comparison between the survival probability estimates of the two methods revealed a better survival probability estimate by the parametric method than the Kaplan-Meier. We also compared the median survival time of male and female patients individually with descriptive, parametric, and non-parametric methods of analysis. The parametric survival analysis is more robust and efficient because it is based on a well-defined parametric probabilistic distribution, hence preferred over the non-parametric Kaplan-Meier estimate. This study offers therapeutic significance for further enhancement to treat patients with Acute Myeloid Leukemia. 展开更多
关键词 Acute Myeloid Leukemia (AML) Generalized Extreme Value (GEV) Distribution Probability Weighted Moment (PWM) Method Kaplan-Meier (KM) Estimate
在线阅读 下载PDF
文章速递Sense of Coherence, Self-Disclosure, and Depression in Lung Cancer Patients 认领
16
作者 Constantinos Togas Fotios Anagnostopoulos George Alexias 《医学心理学(英文)》 2021年第1期11-26,共16页
This study aimed to investigate the relationship between <span style="font-family:Verdana;">sense</span><span style="font-family:Verdana;"> of coherence and depression and the med... This study aimed to investigate the relationship between <span style="font-family:Verdana;">sense</span><span style="font-family:Verdana;"> of coherence and depression and the mediating role of self-disclosure in lung cancer patients. Α cross-sectional study was conducted in “Sotiria” Chest Diseases Hospital, Greece, with a sample of 200 lung cancer patients. </span><span style="font-family:Verdana;">The</span><span style="font-family:Verdana;"> administered questionnaires included demographic-medical information, SOC-13, Distress Disclosure Index, and CES-D scale. </span><span style="font-family:Verdana;">Analysis</span><span style="font-family:Verdana;"> was performed by SPSS v.23 and PROCESS. Depression was common (41%) and negatively correlated to SOC (rho = -</span><span><span><span style="font-family:;" "=""><span><span style="font-family:Verdana;">0.843, df = 198, p < 0.001), while self-disclosure did not mediate this relationship. Hierarchical linear regression analysis showed that patients with weak SOC, disease recurrence, metastases, low income, and receiving therapy in Day clinic had higher levels of depression. In conclusion, a strong SOC represents a protective factor against depression in lung cancer patients. Consequently, there is a need for targeted interventions, which should mainly increase </span><span style="font-family:Verdana;">SOC</span><span style="font-family:Verdana;"> of these patients.</span></span></span></span></span> 展开更多
关键词 Lung Cancer Sense of Coherence Self-Disclosure Depression Quantitative Method
在线阅读 下载PDF
文章速递Fruit Mass of <i>Carica papaya</i>L. from Cultivars Aliança and THB from the Width and Length of the Fruit 认领
17
作者 Karina Tiemi Hassuda dos Santos Vinicius de Souza Oliveira +3 位作者 Gleyce Pereira Santos Jéssica Sayuri Hassuda Santos Omar Schmildt Edilson Romais Schmildt 《农业科学(英文)》 2021年第1期9-17,共9页
Papaya (<em>Carica papaya</em> L.) is a typical plant with a tropical climate, but also grown in subtropical regions. Using mathematical models well-adjusted allows with good precision to estimate characte... Papaya (<em>Carica papaya</em> L.) is a typical plant with a tropical climate, but also grown in subtropical regions. Using mathematical models well-adjusted allows with good precision to estimate characteristics of interest. The objective was to adjust an equation tha<em></em>t estimates the fruit mass for each cultivar of papaya, Alian<span style="white-space:nowrap;">&#231;</span>a and THB, using only one measure, length or width. The experiment was conducted in the municipality of Linhares in the state of Espírito Santo, Brazil. Seedlings were planted on the same day, spaced 3.6 × 1.5 m and in rows side by side. Initially, the equations were modeled, they were linearized and then the covariance analysis was performed in order to verify the possibility of an equation that would serve both cultivars. As the covariance was significant, it was necessary to develop equations for each cultivar. To obtain the growth equations, 350 fruits of cultivar Alian<span style="white-space:nowrap;">&#231;</span>a and 550 of THB were used. The validation was performed with 50 fruits of each. The characteristics evaluated were the largest width (W in mm), the longest fruit length (L, in mm) and the observed mass (OM in g). The equations that best fit were those of the power model that use width (W) as an independent variable. 展开更多
关键词 Non-Destructive Method Regression Validation Mathematical Equations Growth Modeling
在线阅读 下载PDF
文章速递Modelling of the High-Energy Ball Milling Process 认领
18
作者 Mohsen Mhadhbi 《材料物理与化学进展(英文)》 2021年第1期31-44,共14页
In this paper, the milling parameters of high energy ball mill (Fritsch Pulverisette 7) like vial geometry, number and size of balls and speed of the mill were modelled and discussed. Simulations through discrete elem... In this paper, the milling parameters of high energy ball mill (Fritsch Pulverisette 7) like vial geometry, number and size of balls and speed of the mill were modelled and discussed. Simulations through discrete element method (DEM) provide correlation between the milling parameters. A mathematical model is used to improve and develop this process. The results show that the loss of powder mass can remarkably improve the performance of milling. The balls made of stainless-steel have a positive effect on the milling efficiency. The simulation shows that the high ball milling velocities can contribute to faster particle size reduction. 展开更多
关键词 Ball Mill Modelling Discrete Element Method Planetary Ball Mill High-Energy Ball Milling
在线阅读 下载PDF
文章速递Background Concentration of Copper and Cadmium in Water from a High Industrialized and Urban Coastal System (Baixada Santista, Brazil)—Contribution to a Monitoring Program 认领
19
作者 Elisabete S. Braga Riso D. Ricardo 《地球科学和环境保护期刊(英文)》 2021年第1期132-150,共19页
The Baixada Santista coastal region is well known in the context of the high atmospheric, soil and aquatic pollution levels derived from port, industrial, domestic and urban activities existent there, mainly in functi... The Baixada Santista coastal region is well known in the context of the high atmospheric, soil and aquatic pollution levels derived from port, industrial, domestic and urban activities existent there, mainly in function of the Cubat<span style="white-space:nowrap;">&atilde;</span>o industrial pole and port of Santos. The contamination by trace metals in this region is rarely measured in water column when compared with metal determinations in sediment studies. This study aims to evidence the levels of dissolved copper and total cadmium concentrations in estuarine and seawater waters using electrochemical analysis as a chronopotentiometric stripping polarography, which could improve the environmental monitoring program. The study was performed in the Bay of Santos reaching two estuarine channels (Santos and S<span style="white-space:nowrap;">&atilde;</span>o Vicente Channels) in two tide periods in summer 2001. This region is influenced by terrestrial and anthropogenic inputs of trace metals to seawater. The results showed that dissolved copper and total cadmium in water presented the maxima concentrations of 45.4 nM and 2.6 nM respectively. They not reached the limits proposed by Brazilian Environmental Law (CONAMA), that indicate, as reference, a maximum of 123 nM and 350 nM for dissolved copper and total cadmium, respectively and, considering seawater coastal system (salinity > 30, class 2) and also brackish water (class 2). Although the values were under the maximum recommended for each metal, the concentrations were not negligible in relation to the other polluted areas in the world. The values distribution along the system showed a progressive increase in direction to the inner part of the system that naturally compromises the local biota whose is more exposed to the bioaccumulation processes, and this data corresponds to an important reference preterit value to the monitoring program. The trace metal bioaccumulation by mangrove vegetation and by the biota in the internal part of the estuarine channels increase the risk of the poorly population that living in the internal part of the estuary, used to the seafood consumption. The contribution of this study is important to guide the protective policies destined to recuperate the natural conditions of this system, mainly considering that in the decade 1980, there was a case of toxic contamination, causing hydrocephaly in newborns. It proves the existence of risks to the human health and to the balance of the ecosystem, even with the decrease of pollution after that, the environmental evaluation needs to know the background values to guide environmental protection. 展开更多
关键词 Dissolved Toxic Metals Tide Variation Chronopotentiometric Analytical Method Metal Biogeochemical Cycles Bay of Santos
在线阅读 下载PDF
文章速递Study on Local Optical Flow Method Based on YOLOv3 in Human Behavior Recognition 认领
20
作者 Hao Zheng Jianfang Liu Mengyi Liao 《电脑和通信(英文)》 2021年第1期10-18,共9页
In the process of human behavior recognition, the traditional dense optical flow method has too many pixels and too much overhead, which limits the running speed. This paper proposed a method combing YOLOv3 (You Only ... In the process of human behavior recognition, the traditional dense optical flow method has too many pixels and too much overhead, which limits the running speed. This paper proposed a method combing YOLOv3 (You Only Look Once v3) and local optical flow method. Based on the dense optical flow method, the optical flow modulus of the area where the human target is detected is calculated to reduce the amount of computation and save the cost in terms of time. And then, a threshold value is set to complete the human behavior identification. Through design algorithm, experimental verification and other steps, the walking, running and falling state of human body in real life indoor sports video was identified. Experimental results show that this algorithm is more advantageous for jogging behavior recognition. 展开更多
关键词 YOLOv3 Local Optical Flow Method Human Behavior Recognition
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈