检索结果-南通市图书馆

Application of Predictive Model for Efficient Cassava (Manihot esculenta Crantz) Yield in the Face of Climate Variability in Enugu State, Nigeria

引用

American Journal of Climate Change 2024年第2期13卷 361-389页

作者： Emeka Bright Ogbuene Tonia Nkiru Nwobodo Obianuju Gertrude Aloh Achoru fred Emeka Josiah C. Ogbuka Vivian Amarachi Ozorme Andrew M. Oroke Obiageli Jacinta Okolo Anwara Obianuju Amara E. S. Enemuo Centre for Environmental Management and Control (CEMAC) University of Nigeria Nsukka Nigeria Department of Geography University of Nigeria Nsukka Nigeria Department of Geography and Meteorology Enugu State University of Science and Technology (ESUT) Enugu Nigeria School of Civil Engineering Newcastle University Newcastle upon Tyne UK

Climate variability as occasioned by conditions such as extreme rainfall and temperature, rainfall cessation, and irregular temperatures has considerable impact on crop yield and food security. This study develops a predictive model for cassava yield (Manihot esculenta Crantz) amidst climate variability in rainfed zone of Enugu State, Nigeria. This study utilized data of climate variables and tonnage of cassava yield spanning from 1971 to 2012;as well as information from a questionnaire and focus group discussion from farmers across two seasons in 2023 respectively. Regression analysis was employed to develop the predictive model equation for seasonal climate variability and cassava yield. The rainfall and temperature anomalies, decadal change in trend of cassava yield and opinion of farmers on changes in rainfall season were also computed in the study. The result shows the following relationship between cassava and all the climatic variables: R2 = 0.939;P = 0.00514;Cassava and key climatic variables: R2 = 0.560;P = 0.007. The result implies that seasonal rainfall, temperature, relative humidity, sunshine hours and radiation parameters are key climatic variables in cassava production. This is supported by computed rainfall and temperature anomalies which range from −478.5 to 517.8 mm as well as −1.2˚C to 2.3˚C over the years. The questionnaire and focus group identified that farmers experienced at one time or another, late onset of rain, early onset of rain or rainfall cessation over the years. The farmers are not particularly sure of rainfall and temperature characteristics at any point in time. The implication of the result of this study is that rainfall and temperature parameters determine the farming season and quantity of productivity. Hence, there is urgent need to address the situation through effective and quality weather forecasting network which will help stem food insecurity in the study area and Nigeria at large. The study made recommendations such as a

关键词： Climate Variability Cassava (Manihot esculenta Crantz) Predictive Model Yield

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Application of Machine Learning for Flood Prediction and Evaluation in Southern Nigeria

引用

Atmospheric and Climate Sciences 2024年第3期14卷 299-316页

作者： Emeka Bright Ogbuene Chukwumeuche Ambrose Eze Obianuju Getrude Aloh Andrew Monday Oroke Damian Onuora Udegbunam Josiah Chukwuemeka Ogbuka fred Emeka Achoru Vivian Amarachi Ozorme Obianuju Anwara Ikechukwu Chukwunonyelum Anthonia Nneka Nebo Obiageli Jacinta Okolo Centre for Environmental Management and Control (CEMAC) University of Nigeria Enugu Nigeria Department of Geography Enugu State University of Science and Technology ESUT Enugu Nigeria School of Civil Engineering Newcastle University Newcastle upon Tyne UK

This study explored the application of machine learning techniques for flood prediction and analysis in southern Nigeria. Machine learning is an artificial intelligence technique that uses computer-based instructions to analyze and transform data into useful information to enable systems to make predictions. Traditional methods of flood prediction and analysis often fall short of providing accurate and timely information for effective disaster management. More so, numerical forecasting of flood disasters in the 19th century is not very accurate due to its inability to simplify complex atmospheric dynamics into simple equations. Here, we used Machine learning (ML) techniques including Random Forest (RF), Logistic Regression (LR), Naïve Bayes (NB), Support Vector Machine (SVM), and Neural Networks (NN) to model the complex physical processes that cause floods. The dataset contains 59 cases with the goal feature “Event-Type”, including 39 cases of floods and 20 cases of flood/rainstorms. Based on comparison of assessment metrics from models created using historical records, the result shows that NB performed better than all other techniques, followed by RF. The developed model can be used to predict the frequency of flood incidents. The majority of flood scenarios demonstrate that the event poses a significant risk to people’s lives. Therefore, each of the emergency response elements requires adequate knowledge of the flood incidences, continuous early warning service and accurate prediction model. This study can expand knowledge and research on flood predictive modeling in vulnerable areas to inform effective and sustainable contingency planning, policy, and management actions on flood disaster incidents, especially in other technologically underdeveloped settings.

关键词： Machine Learning Flood Prediction Evaluation Southern Nigeria

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Benefits of High-voltage SiC-based Power Electronics in Medium-voltage Power-distribution Grids

引用

Chinese Journal of Electrical Engineering 2021年第1期7卷 1-26页

作者： fred Wang Shiqi Ji Department of Electrical Engineering and Computer Science The University of TennesseeTN 37996USA Oak Ridge National Lab Oak RidgeTN 37830USA Department of Electrical Engineering Tsinghua UniversityBeijing 100084China

Medium-voltage(MV)power electronics equipment has been increasingly applied m distnbution grids,and high-voltage(HV)silicon carbide(SiC)power semiconductors have attracted considerable attention in recent *** paper first overviews the development and status of HV SiC power ***,MV power-converter applications in distribution grids are summarized and the benefits of HV SiC in these applications are ***,including conventional and asynchronous microgrids,that can fully demonstrate the benefits of HV SiC power semiconductors are selected to investigate the benefits of HV SiC in detail,including converter-level benefits and system-level ***,an asynchronous microgrid power-conditioning system(PCS)prototype using a 10 kV SiC MOSFET is presented.

关键词： Silicon carbide power semiconductor distribution grid asynchronous microgrid power-conditioning system

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Universal optimality of digital nets and lattice designs

引用

Science China Mathematics 2009年第11期52卷 2309-2320页

作者： HICKERNELL fred J Department of Applied Mathematics Illinois Institute of Technology

This article considers universal optimality of digital nets and lattice designs in a regression model. Based on the equivalence theorem for matrix means and majorization theory,the necessary and sufficient conditions for lattice designs being φp-and universally optimal in trigonometric function and Chebyshev polynomial regression models are obtained. It is shown that digital nets are universally optimal for both complete and incomplete Walsh function regression models under some specified conditions,and are also universally optimal for complete Haar wavelet regression models but may not for incomplete Haar wavelet regression models.

关键词： Chebyshev polynomial Haar wavelet Trigonometric function Walsh function 62K15 62K10

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A methodology for simulating 2D shock-induced dynamic stall at flight test-based fluctuating freestream

引用

Chinese Journal of Aeronautics 2019年第10期32卷 2223-2238页

作者： Khider AL-JABURI Daniel FESZTY fred NITZSCHE Department of Mechanical and Aerospace Engineering Carleton University

A comprehensive methodology for simulating 2 D dynamic stall at fluctuating freestream is proposed in this paper.2 D CFD simulation of a SC1095 airfoil exposed to a fluctuating freestream of Mach number 0.537±0.205 and Reynolds number 6.1×10~6(based on the mean Mach number)and undergoing a 10°±10°pitch oscillation with a frequency of 4.25 Hz was *** conditions were selected to be representative of the flow experienced by a helicopter rotor airfoil section in a real-life fast forward *** constant freestream dynamic stall as well as fluctuating freestream dynamic stall simulations were conducted and *** methodology was carefully validated with experimental data for both transonic flow and dynamic stall under fluctuating ***,the results suggest that the fluctuating freestream alters the dynamic stall mechanism documented for constant freestream in a major way,emphasizing that inclusion of this effect in the prediction of dynamic stall related rotor loads is imperative for rotor performance analysis and blades design.

关键词： Mach fluctuation Pitching airfoil Shock-induced dynamic stall Transonic flow Unsteady freestream velocity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Challenges of Multidisciplinary Education in Computer Science

引用

Journal of Computer Science & Technology 2011年第4期26卷 636-642页

作者： fred S.Roberts DIMACS Center Rutgers UniversityJerseyNew BrunswickNJU.S.A.

Some of the most important problems facing the United States and China, indeed facing our entire planet, require approaches that are fundamentally multidisciplinary in nature. Many of those require skills in computer science （CS）, basic understanding of another discipline, and the ability to apply the skills in one discipline to the problems of another. Modern training in computer science needs to prepare students to work in other disciplines or to work on multidisciplinary problems. What do we do to prepare them for a multidisciplinary world when there are already too many things we want to teach them about computer science？ This paper describes successful examples of multidisciplinary education at the interface between CS and the biological sciences, as well as other examples involving CS and security, CS and sustainability, and CS and the social and economic sciences. It then discusses general principles for multidisciplinary education of computer scientists.

关键词： multidisciplinary biology sustainability security social sciences economics education

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Adsorption mechanisms of PFOA onto activated carbon anchored with quaternary ammonium/epoxide-forming compounds: A combination of experiment and model studies

引用

Journal of Environmental Sciences 2020年第12期32卷 94-102页

作者： Chen Yuan Yang Huang fred SCannon Zhiwei Zhao Shenzhen Academy of Environmental Science Shenzhen 518001China College of Urban Construction and Environmental Engineering Chongqing UniversityChongqing 400045China Department of Civil and Environmental Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA College of Resources and Environment Chengdu University of Information TechnologyChengdu 610225China

When wood-based activated carbon was tailored with quaternary ammonium/epoxide(QAE) forming compounds(QAE-AC), this tailoring dramatically improved the carbon's effectiveness for removing perfluorooctanoic acid(PFOA) from groundwater. With favorable tailoring, QAE-AC removed PFOA from groundwater for 118,000 bed volumes before halfbreakthrough in rapid small scale column tests, while the influent PFOA concentration was 200 ng/L. The tailoring involved pre-dosing QAE at an array of proportions onto this carbon, and then monitoring bed life for PFOA removal. When pre-dosing with 1 mL QAE, this PFOA bed life reached an interim peak, whereas bed life was less following 3 mL QAE pre-dosing, then PFOA bed life exhibited a steady rise for yet subsequently higher QAE pre-dosing levels. Large-scale atomistic modelling was used herein to provide new insight into the mechanism of PFOA removal by QAE-AC. Based on experimental results and modelling, the authors perceived that the QAE's epoxide functionalities cross-linked with phenolics that were present along the activated carbon's graphene edge sites, in a manner that created mesopores within macroporous regions or created micropores within mesopores regions. Also, the QAE could react with hydroxyls outside of these pore, including the hydroxyls of both graphene edge sites and other QAE molecules. This latter reaction formed new pore-like structures that were external to the activated carbon grains. Adsorption of PFOA could occur via either charge balance between negatively charged PFOA with positively charged QAE, or by van der Waals forces between PFOA's fluoro-carbon tail and the graphene or QAE carbon surfaces.

关键词： Perfluorooctanoic acid Nitrate Carbon Atomistic model Adsorption mechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Students and Scholars in the Global Community:Challenges of Integration

引用

Frontiers of Education in China 2014年第3期9卷 297-302页

作者： fred DERVIN Department of Teacher Education University of HelsinkiHelsinki 00790Finland

China has a long higher education tradition that has evolved over more than two millennia(Zha,2012,p.452).As with other systems of higher education,China has adopted elements from and been influenced by many varied models of the university over its long *** the reform and opening up of the end of the 1970s,China has also felt the pressure of“the international imperative in higher education”(Altbach,2013).But this is not the first time that internationalization is taking place in Chinese *** the founding of the People’s Republic of China,many Chinese people went abroad to study.

关键词： has education founding

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A final size relation for epidemic models of vectortransmitted diseases

引用

Infectious Disease Modelling 2017年第1期2卷 12-20页

作者： fred Brauer University of British Columbia VancouverBCCanada

We formulate and analyze an age of infection model for epidemics of diseases transmitted by a vector,including the possibility of direct transmission as *** show how to determine a basic reproduction *** there is no explicit final size relation as for diseases transmitted directly,we are able to obtain estimates for the final size of the epidemic.

关键词： number. relation size

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A singular perturbation approach to epidemics of vectortransmitted diseases

引用

Infectious Disease Modelling 2019年第1期4卷 115-123页

作者： fred Brauer University of British Columbia Vancouver BCCanada

In vector-borne epidemic models there is often a substantial difference between the vector and host time *** makes it possible to use the quasi-steady-state to obtain final size relations.

关键词： perturbation singular quasi

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：