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Blow-up behavior of Hammerstein-type delay Volterra integral equations

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Frontiers of mathematics in China 2013年第2期8卷 261-280页

作者： Zhanwen YANG hermann brunner Science Research Center Academy of Fundamental and Interdisciplinary Science department of mathematics Harbin Institute of Technology Harbin 150001 China department of mathematics Hong Kong Baptist University Hong Kong SAR China department of mathematics and statistics Memorial University of NewfoundlandSt. John's NL AIC 557 Canada

We consider the blow-up behavior of Hammerstein-type delay Volterra integral equations （DVIEs）. Two types of delays, i.e., vanishing delay （pantograph delay） and non-vanishing delay （constant delay）, are considered. With the same assumptions of Volterra integral equations （VIEs）, in a similar technology to VIEs, the blow-up conditions of the two types of DVIEs are given. The blow-up behaviors of DVIEs with non-vanishing delay vary with different initial functions and the length of the lag, while DVIEs with pantograph delay own the same blow-up behavior of VIEs. Some examples and applications to delay differential equations illustrate this influence.

关键词： Delay Volterra integral equation (DVIE) non-vanishing delay vanishing delay blow-up of solution

Numerical Soliton Solutions for a Discrete Sine-Gordon System

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Communications in Computational Physics 2009年第9期6卷 903-918页

作者： Houde Han Jiwei Zhang hermann brunner department of Mathematical Sciences Tsinghua UniversityBeijing 100084China department of mathematics Hong Kong Baptist UniversityKowloon TongHong KongChina department of mathematics and statistics Memorial University of NewfoundlandSt.John’sNLCanada A1C 5S7

In this paper we use an analytical-numerical approach to find,in a systematic way,new 1-soliton solutions for a discrete sine-Gordon system in one spatial *** the spatial domain is unbounded,the numerical scheme employed to generate these soliton solutions is based on the artificial boundary method.A large selection of numerical examples provides much insight into the possible shapes of these new 1-solitons.

关键词： Sine-Gordon equation soliton solutions numerical single solitons artificial boundary method

Numerical Solution of Blow-Up Problems for NonlinearWave Equations on Unbounded Domains

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Communications in Computational Physics 2013年第8期14卷 574-598页

作者： hermann brunner Hongwei Li Xiaonan Wu department of mathematics Hong Kong Baptist UniversityKowloon TongHong Kong department of mathematics and statistics Memorial University of NewfoundlandSt.John’sNLA1C 5S7Canada College of Mathematical Sciences Shandong Normal UniversityJinan250014P.R.China.

The numerical solution of blow-up problems for nonlinear wave equations on unbounded spatial domains is *** the unified approach,which is based on the operator splitting method,we construct the efficient nonlinear local absorbing boundary conditions for the nonlinear wave equation,and reduce the nonlinear problem on the unbounded spatial domain to an initial-boundary-value problem on a bounded *** the finite difference method is used to solve the reduced problem on the bounded computational ***,a broad range of numerical examples are given to demonstrate the effectiveness and accuracy of our method,and some interesting propagation and behaviors of the blow-up problems for nonlinear wave equations are observed.

关键词： Finite-time blow-up nonlinear wave equation absorbing boundary conditions finite differencemethod unbounded domains

PERFORMANCE OF TWO GENERALIZED ORDER statistics CFAR DETECTORS WITH AUTOMATIC CENSORING TECHNIQUE IN MULTIPLE TARGET SITUATIONS

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Journal of Electronics(China) 1995年第1期12卷 38-47页

作者：何友 hermann Rohling department of Electronic Engineering Technical University of Yantai Yantai 264001 Institute of Telecommunications Technical University of Braunschweig Germany 38092

This paper presents two generalized modified OS-CFAR detectors and an automatic censoring technique. For these two new OS-CFAR detectors, analytic expressions of the false alarm rate, the detection probabilities and the measure of ADT under the Swerling 2 assumption are obtained. Their detection performances are analyzed in homogeneous background and in the presence of strong interfering targets, and they are compared with several previously proposed CFARs.

关键词： Radar Detection CFAR algorithms Clutter

Effect of Climate Variability on Yams (<i>Dioscorea spp</i>.) Production in Central and Northern Benin

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American Journal of Climate Change 2020年第4期9卷 423-440页

作者： Fiacre hermann Adifon Gilbert Atindogbé Daouda Orou Bello Ibouraïman Balogoun Ibouraïma Yabi Joseph Dossou Léonard Ahoton Aliou Saïdou Integrated Soil and Crop Management (ISCM) Unit Soil Sciences Laboratory School of Plant Production Sciences and Techniques Faculty of Agronomic Sciences University of Abomey-Calavi Cotonou Benin Laboratory of Study and Research in Applied and Biometric statistics (LERSAB) Faculty of Agronomic Sciences (FSA) of the University of Abomey-Calavi Cotonou Benin Plant Biology Laboratory School of Plant Production Sciences and Techniques Faculty of Agronomic Sciences University of Abomey-Calavi Cotonou Benin Pierre PAGNEY Laboratory “Climate Water Ecosystem and Development” University of Abomey-Calavi Faculty of Letters Arts and Human Sciences Department of Geography and Spatial Planning Cotonou Benin Laboratory of Bioengineering of Food Processes (LABIOPA) Faculty of Agronomic Sciences (FSA) University of Abomey-Calavi Cotonou Benin

Climate change poses an important constraint to agricultural sector and food security in tropical African countries dominated by rain-fed agriculture. This research focuses on the effects of climate variability on yam production in central and northern Benin. Daily climate data such as temperatures, precipitation, potential evapotranspiration, relative humidity and insolation from 1981 to 2016 were collected at the direction of METEO-Benin. A survey was then conducted with 351 producers to collect their perceptions of the effect of climate variability on the yams production. Descriptive statistics, principal component analysis (PCA) followed by trend analyses, Lamb index calculations and the agro-climatic stress index were carried out. The distribution of rain during the yam cycle (91.5% of those surveyed), the ambient temperature (84.9%), insolation (83.5%), the amount of rainwater that fell during the rainy season (82.2%) and the harmattan (53.3%) are perceived by sociolinguistic groups as climatic factors affecting the growth, the tuberization and yield of yams according to the producers. The results indicate an upward trend in temperature over the period 2001 to 2016 in the transition zone (28.4°C) and in the Northeast (27.76°C) and over the period from 2001 to 2011 in the North-West of Benin (27.71°C), where the average annual temperature during these periods is higher than normal (27.82°C in the center, 27.44°C in the Northeast and 27.42°C to the northwest). This research also shows an instability of the rains with a regular decrease in the rainfall in the Centre and the North-East of the country. The agro-climatic stress index (ISA) and above all the annual rainfall constitute the main climatic factors which determine

关键词： Yam Climate Variability Yield Food Security Benin