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Mineral Fertilizer Use for Optimal Groundnut Production in the Sudano-Guinean and Sudanian Zones of Benin 认领
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作者 Faki O. Chabi Gustave D. Dagbenonbakin +6 位作者 Emile C. Agbangba Issa Mouftaou Augustin O. Bankolé Brice T. Oussou Léonard E. Ahoton Guillaume L. Amadji Aliou Saïdou 《土壤科学期刊(英文)》 2021年第2期72-92,共21页
Abstract This study aims to determine the optimal N, P, K, Mg and Zn rates for groundnut production on Ferric and Plintic Luvisol in the Sudano-Guinean and Sudanian zones of Benin Republic. Two years (2018 and 2019) e... Abstract This study aims to determine the optimal N, P, K, Mg and Zn rates for groundnut production on Ferric and Plintic Luvisol in the Sudano-Guinean and Sudanian zones of Benin Republic. Two years (2018 and 2019) experiment was carried out in the municipality of Ouessè in the Sudano-Guinean zone and Bembèrèkè in the Sudanian zone. The tested nutrient doses were N (0, 20 and 40 kg<span style="white-space:nowrap;">&sdot;</span>ha<sup><span style="white-space:nowrap;">&minus;</span>1</sup>), P (0, 25 and 50 kg<span style="white-space:nowrap;">&sdot;</span>ha<sup><span style="white-space:nowrap;">&minus;</span>1</sup>), K (0, 20 and 40 kg<span style="white-space:nowrap;">&sdot;</span>ha<sup><span style="white-space:nowrap;">&minus;</span>1</sup>), Mg (0, 15 and 30 kg<span style="white-space:nowrap;">&sdot;</span>ha<sup><span style="white-space:nowrap;">&minus;</span>1</sup>) and Zn (0, 4 and 8 kg<span style="white-space:nowrap;">&sdot;</span>ha<sup><span style="white-space:nowrap;">&minus;</span>1</sup>). The Box and Behnken rotating design is used to define the N, P, K, Mg and Zn rate combinations leading to 46 combinations. A completely randomized bloc design was setting up considering farmers as replication. In total, four farmers’ fields were selected. A one-way analysis of variance is carried out on yield data, using the linear mixed-effect model. Response surface analyses were used to determine the optimal doses for each N, P, K, Mg and Zn. Nodule production (6.5 times higher than the control), number of gynophores (2.8 times higher than the control) and root length (19.2 ± 0.2 cm) of groundnut plants were significantly (p = 0.0001) improved with nutrient application. The response surface analysis shows that treatments N-P-K-Mg-Zn of 16.01-20.18-6.70-5.65-2.47 (in the Sudano-Guinean zone) and 13.1-25.07-11.47-0-1.82 (in the Sudanian zone) are the optimal rates that have induced optimal yield of 2.1 t<span style="white-space:nowrap;">&sdot;</span>ha<sup><span style="white-space:nowrap;">&minus;</span>1 展开更多
关键词 Soil Fertility Response Surface Box and Behnken Design Modeling MICRONUTRIENT
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Fruit Mass of <i>Carica papaya</i>L. from Cultivars Aliança and THB from the Width and Length of the Fruit 认领
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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
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基于UG的复杂凹模型腔的造型设计 认领
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作者 李倩 《科技创新与应用》 2021年第2期106-108,共3页
文章根据复杂凹模型腔的结构特点,提出了凹模型腔的建模思路,并用可乐瓶凹模型腔的建模过程进行了验证。为凹模型腔的造型提供了一种切实可行的建模思路。
关键词 凹模型腔 造型 建模思路
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Small Molecular Weight Compounds Antagonistic to Amyloid Peptide<sub>25-35</sub> 认领
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作者 W. Robert Williams 《生物科学与医学(英文)》 2021年第1期41-51,共11页
High levels of the neurotoxic beta-amyloid protein (A<em>β</em>) in patients with Alzheimer’s disease present a significant therapeutic target, although the protein is unlikely to be the sole instigator ... High levels of the neurotoxic beta-amyloid protein (A<em>β</em>) in patients with Alzheimer’s disease present a significant therapeutic target, although the protein is unlikely to be the sole instigator of this condition. A<em>β</em> initiates cell receptor and synapse dysfunction, and causes mitochondrial damage within neurons. Neurotransmitters and various small molecular weight compounds ameliorate the effects of A<em>β</em> on cell membranes. This study uses a molecular modeling technique to compare the structures of A<em>β</em>25-35 and compounds known to antagonize properties of the polypeptide. Compounds provide good fits to the peptide amino acid residues, revealing planarity in their linear structures and fitting points. Compounds and polypeptide share relative molecular similarity, affinity for receptors and apoptosis modulating properties indicative of their potential for competition at neuron membrane sites. The therapeutic targeting of A<em>β</em> by small molecular weight compounds may benefit from a multi-drug approach. 展开更多
关键词 Alzheimer’s Disease Beta-Amyloid Peptide Beta-Amyloid Antagonists Molecular Modeling
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玩具产品造型参数化设计应用 认领
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作者 邓卫斌 宋仁慈 李珺 《设计》 2021年第1期11-13,共3页
优化玩具产品造型设计流程、为玩具造型设计提供新思路。以参数化设计为研究对象,分析参数化设计自身优势,总结其在产品造型设计应用中独特的建模思维方式,设计流程及优势,遵循玩具造型设计原则方法,发掘其与玩具造型设计的契合点,创新... 优化玩具产品造型设计流程、为玩具造型设计提供新思路。以参数化设计为研究对象,分析参数化设计自身优势,总结其在产品造型设计应用中独特的建模思维方式,设计流程及优势,遵循玩具造型设计原则方法,发掘其与玩具造型设计的契合点,创新玩具产品造型。获取自然随机的参数化玩具造型。参数化设计方法为玩具产品造型提供无限可能性,打破惯性思维,给设计师创作提供新思路和想象空间。 展开更多
关键词 参数化 参数化设计 造型 产品造型 玩具设计
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Lagrangian Model PETROMAR-3D to Describe Complex Processes in Marine Oil Spills 认领
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作者 Amilcar E. Calzada Iván Delgado +7 位作者 Carlos Ramos Frank Pérez Dailín Reyes Dayana Carracedo Alejandro Rodríguez Dayron Chang Javier Cabrales Alexander Lobaina 《海洋科学期刊(英文)》 2021年第1期17-40,共24页
The version 2.1 of PETROMAR-3D model, created in the Center for Marine Meteorology of the Meteorology Institute of Cuba, is presented. This Lagrangian model has been designed to describe the physical processes of mari... The version 2.1 of PETROMAR-3D model, created in the Center for Marine Meteorology of the Meteorology Institute of Cuba, is presented. This Lagrangian model has been designed to describe the physical processes of marine oil spills in the face of multiple scenarios of the marine environment. Although it is applicable to any part of the world, it is mainly designed for inter-American seas. The novelty has been to integrate the processes of drift and weathering into a model, with updated methods that incorporate 3D phenomena, a very favorable situation to achieve an operating system in Cuba and the region for the immediate and medium term. Python was chosen as the programming language because it has advanced libraries for numerical modeling, automation work and other useful tools for pre-and post-processing. By means of adapters, an important number of atmospheric, hydrodynamic and wave models have been considered to create the scenarios efficiently. The modular distribution in which the code has been created facilitates its use for other dispersion analysis and biophysical applications. Finally, a set of simple images are presented, aimed at informing decision-makers in order to mitigate the effects of the spill on the environment. 展开更多
关键词 Oil Spill Modeling Lagrangian Model Inter-American Seas
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文章速递Management of residual penile curvature after penile prosthesis placement 认领
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作者 Denis V Krakhotkin David J Ralph +4 位作者 Gideon A Blecher Volodymyr A Chernylovskyi Francesco Greco Evgeny E Bakurov Ruslan A Bugaev 《亚洲男性学杂志:英文版》 SCIE CAS CSCD 2021年第2期129-134,共6页
Residual penile curvature is a common situation following the implantation of a penile prosthesis in patients with Peyronie’s disease.Currently,there is a variety of options for the correction of residual curvature,i... Residual penile curvature is a common situation following the implantation of a penile prosthesis in patients with Peyronie’s disease.Currently,there is a variety of options for the correction of residual curvature,including penile modeling,plication techniques,as well as tunical incision/excision with or without grafting.A literature search of PubMed and Medline databases was conducted from 1964 until 2020,using search terms for all articles in the English language.In this article,we provide a review of the techniques and the outcomes,according to the published literature. 展开更多
关键词 grafting modeling penile curvature penile implant penile prosthesis Peyronie’s disease tunical plication
文章速递并行流水线流程分割与人力调度建模及分析 认领
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作者 沈奥 周树道 +2 位作者 王敏 刘展华 张翼飞 《兵工自动化》 2021年第4期75-80,96,共7页
为解决大型设备定期检查、更换部件等作业时间长、人员利用率低的问题,采用一种对并行流水线流程分割与人力调度建模及分析的方法。在使用甘特图优化单个设备工作流程的基础上,建立工作流程矩阵。根据实际工作要求设置各设备、各专业的... 为解决大型设备定期检查、更换部件等作业时间长、人员利用率低的问题,采用一种对并行流水线流程分割与人力调度建模及分析的方法。在使用甘特图优化单个设备工作流程的基础上,建立工作流程矩阵。根据实际工作要求设置各设备、各专业的工作流程矩阵,依据其相互的数学关系,建立数学模型,设置约束条件,给出流程分割与人力调度求解算法,并以实际问题为例验证模型和算法的性能。结果表明,该方法能优化维护流程规划,缩短作业时间,提高人员利用率。 展开更多
关键词 流程分割 人力调度 建模 分析
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Widespread testing, case isolation and contact tracing may allow safe school reopening with continued moderate physical distancing: A modeling analysis of King County, WA data 认领
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作者 Chloe Bracis Eileen Burns +4 位作者 Mia Moore David Swan Daniel B.Reeves Joshua T.Schiffer Dobromir Dimitrov 《传染病建模》 2021年第1期24-35,共12页
Background:In late March 2020,a“Stay Home,Stay Healthy”order was issued in Washington State in response to the COVID-19 pandemic.On May 1,a 4-phase reopening plan began.We investigated whether adjunctive prevention ... Background:In late March 2020,a“Stay Home,Stay Healthy”order was issued in Washington State in response to the COVID-19 pandemic.On May 1,a 4-phase reopening plan began.We investigated whether adjunctive prevention strategies would allow less restrictive physical distancing to avoid second epidemic waves and secure safe school reopening.Methods:We developed a mathematical model,stratifying the population by age,infection status and treatment status to project SARS-CoV-2 transmission during and after the reopening period.The model was parameterized with demographic and contact data from King County,WA and calibrated to confirmed cases,deaths and epidemic peak timing.Adjunctive prevention interventions were simulated assuming different levels of pre-COVID physical interactions(pC_PI)restored.Results:The best model fit estimated~35%pC_PI under the lockdown which prevented~17,000 deaths by May 15.Gradually restoring 75%pC_PI for all age groups between May 15-July 15 would have resulted in~350 daily deaths by early September 2020.Maintaining<45%pC_PI was required with current testing practices to ensure low levels of daily infections and deaths.Increased testing,isolation of symptomatic infections,and contact tracing permitted 60%pC_PI without significant increases in daily deaths before November and allowed opening of schools with<15 daily deaths.Inpatient antiviral treatment was predicted to reduce deaths significantly without lowering cases or hospitalizations.Conclusions:We predict that widespread testing,contact tracing and case isolation would allow relaxation of physical distancing,as well as opening of schools,without a surge in local cases and deaths. 展开更多
关键词 Mathematical modeling EPIDEMIOLOGY Age structured model Physical distancing Contact tracing
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Modeling the transmission of COVID-19 in the US-A case study 认领
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作者 Chayu Yang Jin Wang 《传染病建模》 2021年第1期195-211,共17页
We propose a mathematical model to investigate the transmission dynamics of COVID-19.The model incorporates both human-to-human and environment-to-human transmission pathways,and employs different transmission rates t... We propose a mathematical model to investigate the transmission dynamics of COVID-19.The model incorporates both human-to-human and environment-to-human transmission pathways,and employs different transmission rates to represent the epidemiological characteristics at different time periods.Using this model and publicly reported data,we perform a case study for Hamilton County,the fourth-most populous county in the state of Tennessee and a region that could represent the typical situation of COVID-19 in the United States(US).Our data fitting and simulation results show that the environment may play an important role in the transmission and spread of the coronavirus.In addition,we numerically simulate a range of epidemic scenarios and make near-term forecasts on the development and trend of COVID-19 in Hamilton County. 展开更多
关键词 COVID-19 transmission Mathematical modeling Data fitting
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Petro Gram: An excel-based petrology program for modeling of magmatic processes 认领
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作者 Mesut Gündüz Kürsad Asan 《地学前缘:英文版》 SCIE CAS 2021年第1期81-92,共12页
Petro Gram is an Excel?based magmatic petrology program that generates numerical and graphical models.Petro Gram can model the magmatic processes such as melting,crystallization,assimilation and magma mixing based on ... Petro Gram is an Excel?based magmatic petrology program that generates numerical and graphical models.Petro Gram can model the magmatic processes such as melting,crystallization,assimilation and magma mixing based on the trace element and isotopic data.The program can produce both inverse and forward geochemical models for melting processes(e.g.forward model for batch,fractional and dynamic melting,and inverse model for batch and dynamic melting).However,the program uses a forward modeling approach for magma differentiation processes such as crystallization(EC:Equilibruim Crystallization,FC:Fractional Crystallization,IFC:Imperfect Fractional Crystallization and In-situ Crystallization),assimilation(AFC:Assimilation Fractional Crystallization,Decoupled FC-A:Decoupled Fractional Crystallization and Assimillation,A-IFC:Assimilation and Imperfect Fractional Crystallization)and magma mixing.One of the most important advantages of the program is that the melt composition obtained from any partial melting model can be used as a starting composition of the crystallization,assimilation and magma mixing.In addition,Petro Gram is able to carry out the classification,tectonic setting,multi-element(spider)and isotope correlation diagrams,and basic calculations including Mg^#,Eu/Eu^*,εSrandεNdwidely used in magmatic petrology. 展开更多
关键词 PetroGram Magmatic petrology Geochemical modeling Partial melting CRYSTALLIZATION ASSIMILATION Magma mixing
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A survey of script learning 认领
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作者 Yi HAN Linbo QIAO +3 位作者 Jianming ZHENG Hefeng WU Dongsheng LI Xiangke LIAO 《信息与电子工程前沿:英文版》 SCIE EI 2021年第3期341-373,共33页
Script is the structured knowledge representation of prototypical real-life event sequences.Learning the commonsense knowledge inside the script can be helpful for machines in understanding natural language and drawin... Script is the structured knowledge representation of prototypical real-life event sequences.Learning the commonsense knowledge inside the script can be helpful for machines in understanding natural language and drawing commonsensible inferences.Script learning is an interesting and promising research direction,in which a trained script learning system can process narrative texts to capture script knowledge and draw inferences.However,there are currently no survey articles on script learning,so we are providing this comprehensive survey to deeply investigate the standard framework and the major research topics on script learning.This research field contains three main topics:event representations,script learning models,and evaluation approaches.For each topic,we systematically summarize and categorize the existing script learning systems,and carefully analyze and compare the advantages and disadvantages of the representative systems.We also discuss the current state of the research and possible future directions. 展开更多
关键词 Script learning Natural language processing Commonsense knowledge modeling Event reasoning
An action-based Markov chain modeling approach for predicting the window operating behavior in office spaces 认领
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作者 Xin Zhou Tiance Liu +2 位作者 Da Yan Xing Shi Xing Jin 《建筑模拟(英文)》 SCIE EI 2021年第2期301-315,共15页
Reliable energy and performance prediction for building design and planning is important for newly-designed or retrofitted buildings.Window operating behavior has an important influence on the ventilation and energy c... Reliable energy and performance prediction for building design and planning is important for newly-designed or retrofitted buildings.Window operating behavior has an important influence on the ventilation and energy consumption of these buildings under different realistic scenarios.Therefore,quantitatively describing this behavior and constructing a prediction model are important.In this work,an action-based Markov chain modeling approach for predicting window operating behavior in office spaces was proposed.Two summer measurement data(2016 and 2018)were used to verify the accuracy and validity of the modeling approach.The opening rate,outdoor temperature,time distribution,and on-off curve were proposed as four inspection standards.This study also compared the prediction performance between the action-based Markov chain modeling approach with the state-based Markov chain modeling approach,which is the most popular modeling approach to model occupant window operating behavior.This study proved that the yearly variation of occupants’behavior performed a form of action that remained unchanged during a certain period.Meanwhile,the results also proved that the action-based Markov chain modeling approach can reflect the actual window operating behavior accurately within an open-plan office,which is a beneficial supplement for energy-consumption simulation software in a window-state prediction module.The state-based Markov chain modeling approach showed better stability and accuracy in terms of the opening rate,whereas the action-based Markov chain modeling approach showed good consistency with the measurement data in the on-off curves and in situations with little data.For the on-off curves,the accuracy of action-based modeling approach in the prediction of window open-state is 20%higher. 展开更多
关键词 window operating behavior stochastic-numerical model action-based modeling approach stochastic model verification
2.5D有限元建模关键问题——边界条件、网格划分及计算域选取 认领
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作者 王瑞 胡志平 +2 位作者 任翔 李芳涛 温馨 《振动工程学报》 EI 北大核心 2021年第1期80-88,共9页
为了提高2.5D有限元数值计算的求解精度及建模效率,分析了移动荷载作用下地基系统的动力响应特点,确定了计算域选取及网格划分的基本规则,评价了地基分层对波场的影响及边界的波动吸收效果,提出了可以规避边界影响的建模思路。分析结果... 为了提高2.5D有限元数值计算的求解精度及建模效率,分析了移动荷载作用下地基系统的动力响应特点,确定了计算域选取及网格划分的基本规则,评价了地基分层对波场的影响及边界的波动吸收效果,提出了可以规避边界影响的建模思路。分析结果表明:当计算域尺寸满足低频振动要求(约60 m)时,反射波对计算结果的影响可以忽略;建模时可以采用辐射状网格划分,最小网格尺寸需满足高频振动要求(约0.5-1.0 m)。荷载运行速度小于地基瑞利波速时没有波动传播现象,建议直接采用固定边界;荷载运行速度大于地基瑞利波速时可以通过切取局部计算域的方式规避反射波的影响,此时计算域半宽和纵向空间范围的选取需要遵循与马赫锥锥角和列车全长相关的几何关系。荷载影响深度内的地基分层会扰乱地基波场,当地基上覆软弱土层或软弱夹层时,波动会在软土层聚集并在加载点后形成多个马赫锥。 展开更多
关键词 分层地基 建模 2.5D有限元 网格划分 吸收边界
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3D printing of tissue engineering scaffolds:a focus on vascular regeneration 认领
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作者 Pengju Wang Yazhou Sun +3 位作者 Xiaoquan Shi Huixing Shen Haohao Ning Haitao Liu 《生物设计与制造(英文)》 SCIE EI 2021年第2期344-378,共35页
Tissue engineering is an emerging means for resolving the problems of tissue repair and organ replacement in regenerative medicine.Insufficient supply of nutrients and oxygen to cells in large-scale tissues has led to... Tissue engineering is an emerging means for resolving the problems of tissue repair and organ replacement in regenerative medicine.Insufficient supply of nutrients and oxygen to cells in large-scale tissues has led to the demand to prepare blood vessels.Scaffold-based tissue engineering approaches are effective methods to form new blood vessel tissues.The demand for blood vessels prompts systematic research on fabrication strategies of vascular scaffolds for tissue engineering.Recent advances in 3D printing have facilitated fabrication of vascular scaffolds,contributing to broad prospects for tissue vascularization.This review presents state of the art on modeling methods,print materials and preparation processes for fabrication of vascular scaffolds,and discusses the advantages and application fields of each method.Specially,significance and importance of scaffold-based tissue engineering for vascular regeneration are emphasized.Print materials and preparation processes are discussed in detail.And a focus is placed on preparation processes based on 3D printing technologies and traditional manufacturing technologies including casting,electrospinning,and Lego-like construction.And related studies are exemplified.Transformation of vascular scaffolds to clinical application is discussed.Also,four trends of 3D printing of tissue engineering vascular scaffolds are presented,including machine learning,near-infrared photopolymerization,4D printing,and combination of self-assembly and 3D printing-based methods. 展开更多
关键词 Tissue engineering 3D printing Vascular scaffolds Print materials Modeling methods
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Investigating different methods used for approximating pillar loads in longwall coal mines 认领
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作者 Deniz Tuncay a Ihsan Berk Tulu a Ted Klemetti 《矿业科学技术学报:英文版》 SCIE EI 2021年第1期23-32,共10页
Accurately estimating load distributions and ground responses around underground openings play a significant role in the safety of the operations in underground mines.Adequately designing pillars and other support mea... Accurately estimating load distributions and ground responses around underground openings play a significant role in the safety of the operations in underground mines.Adequately designing pillars and other support measures relies highly on the accurate assessment of the loads that will be carried by them,as well as the load-bearing capacities of the supports.There are various methods that can be used to approximate mining-induced loads in stratified rock masses to be used in pillar design.The empirical methods are based on equations derived from large databases of various case studies.They are implemented in government approved design tools and are widely used.There are also analytical and numerical techniques used for more detailed analysis of the induced loads.In this study,two different longwall mines with different panel width-to-depth ratios are analyzed using different methods.The empirical method used in the analysis is the square-decay stress function that uses the abutment angle concept,implemented in pillar design software developed by the National Institute for Occupational Safety and Health(NIOSH).The first numerical method used in the analysis is a displacement-discontinuity(DD)variation of the boundary element method,LaModel,which utilizes the laminated overburden model.The second numerical method used in the analysis is Fast Lagrangian Analysis of Continua(FLAC)with the numerical modeling approach recently developed at West Virginia University which is based on the approach developed by NIOSH.The model includes the 2D slice of a cross-section along the width of the panel with the chain pillar system that also includes the different stratigraphic layers of the overburden.All three methods gave similar results for the shallow mine,both in terms of load percentages and distribution where the variation was more obvious for the deep cover mine.The FLAC3D model was observed to better capture the stress changes observed during the field measurements for both the shallow and deep cover cases.This study all 展开更多
关键词 Abutment loads Numerical modeling LaModel FLAC3D Longwall coal mines
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Three-dimensional frequency-domain full waveform inversion based on the nearly-analytic discrete method 认领
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作者 DeYao Zhang WenYong Pan +3 位作者 DingHui Yang LingYun Qiu XingPeng Dong WeiJuan Meng 《地球与行星物理:英文版》 2021年第2期149-157,共9页
The nearly analytic discrete(NAD)method is a kind of finite difference method with advantages of high accuracy and stability.Previous studies have investigated the NAD method for simulating wave propagation in the tim... The nearly analytic discrete(NAD)method is a kind of finite difference method with advantages of high accuracy and stability.Previous studies have investigated the NAD method for simulating wave propagation in the time-domain.This study applies the NAD method to solving three-dimensional(3D)acoustic wave equations in the frequency-domain.This forward modeling approach is then used as the“engine”for implementing 3D frequency-domain full waveform inversion(FWI).In the numerical modeling experiments,synthetic examples are first given to show the superiority of the NAD method in forward modeling compared with traditional finite difference methods.Synthetic 3D frequency-domain FWI experiments are then carried out to examine the effectiveness of the proposed methods.The inversion results show that the NAD method is more suitable than traditional methods,in terms of computational cost and stability,for 3D frequency-domain FWI,and represents an effective approach for inversion of subsurface model structures. 展开更多
关键词 THREE-DIMENSION FREQUENCY-DOMAIN NAD method forward modeling full waveform inversion
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Assessing the future progression of COVID-19 in Iran and its neighbors using Bayesian models 认领
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作者 Navid Feroze 《传染病建模》 2021年第1期343-350,共8页
Background:The short term forecasts regarding different parameters of the COVID-19 are very important to make informed decisions.However,majority of the earlier contributions have used classical time series models,suc... Background:The short term forecasts regarding different parameters of the COVID-19 are very important to make informed decisions.However,majority of the earlier contributions have used classical time series models,such as auto regressive integrated moving average(ARIMA)models,to obtain the said forecasts for Iran and its neighbors.In addition,the impacts of lifting the lockdowns in the said countries have not been studied.The aim of this paper is to propose more flexible Bayesian structural time series(BSTS)models for forecasting the future trends of the COVID-19 in Iran and its neighbors,and to compare the predictive power of the BSTS models with frequently used ARIMA models.The paper also aims to investigate the casual impacts of lifting the lockdown in the targeted countries using proposed models.Methods:We have proposed BSTS models to forecast the patterns of this pandemic in Iran and its neighbors.The predictive power of the proposed models has been compared with ARIMA models using different forecast accuracy criteria.We have also studied the causal impacts of resuming commercial/social activities in these countries using intervention analysis under BSTS models.The forecasts for next thirty days were obtained by using the data from March 16 to July 22,2020.These data have been obtained from Our World in Data and Humanitarian Data Exchange(HDX).All the numerical results have been obtained using R software.Results:Different measures of forecast accuracy advocated that forecasts under BSTS models were better than those under ARIMA models.Our forecasts suggested that the active numbers of cases are expected to decrease in Iran and its neighbors,except Afghanistan.However,the death toll is expected to increase at more pace in majority of these countries.The resuming of commercial/social activities in these countries has accelerated the surges in number of positive cases.Conclusions:The serious efforts would be needed to make sure that these expected figures regarding active number of cases come true.Iran and its 展开更多
关键词 Infectious disease modeling Bayesian time series models ARIMA models
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Mathematical modeling of COVID-19 infection dynamics in Ghana: Impact evaluation of integrated government and individual level interventions 认领
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作者 Duah Dwomoh Samuel Iddi +4 位作者 Bright Adu Justice Moses Aheto Kojo Mensah Sedzro Julius Fobil Samuel Bosomprah 《传染病建模》 2021年第1期381-397,共17页
The raging COVID-19 pandemic is arguably the most important threat to global health presently.Although there Although there is currently a a a vaccine,preventive measures have been proposed to reduce the spread of inf... The raging COVID-19 pandemic is arguably the most important threat to global health presently.Although there Although there is currently a a a vaccine,preventive measures have been proposed to reduce the spread of infection but the efficacy of these interventions,and their likely impact on the number of COVID-19 infections is unknown.In this study,we proposed the SEIQHRS model(susceptible-exposed-infectious-quarantinehospitalized-recovered-susceptible)model that predicts the trajectory of the epidemic to help plan an effective control strategy for COVID-19 in Ghana.We provided a short-term forecast of the early phase of the epidemic trajectory in Ghana using the generalized growth model.We estimated the effective basic Reproductive number Re in real-time using three different estimation procedures and simulated worse case epidemic scenarios and the impact of integrated individual and government interventions on the epidemic in the long term using compartmental models.The maximum likelihood estimates of Re and the corresponding 95%confidence interval was 2.04[95%CI:1.82-2.27;12th March-7th April 2020].The Re estimate using the exponential growth method was 2.11[95%CI:2.00-2.24]within the same period.The Re estimate using time-dependent(TD)method showed a gradual decline of the Effective Reproductive Number since March 12,2020 when the first 2 index cases were recorded but the rate of transmission remains high(TD:Re=2.52;95%CI:[1.87-3.49]).The current estimate of Re based on the TD method is 1.74[95%CI:1.41-2.10;(13th May 2020)]but with comprehensive integrated government and individual level interventions,the Re could reduce to 0.5 which is an indication of the epidemic dying out in the general population.Our results showed that enhanced government and individual-level interventions and the intensity of media coverage could have a substantial effect on suppressing transmission of new COVID-19 cases and reduced death rates in Ghana until such a time that a potent vaccine or drug is discovered. 展开更多
关键词 COVID-19 Mathematical modeling INTERVENTION Effective reproductive number Infectious disease Differential equations
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基于多元回归算法的激光位移传感器非线性误差建模和补偿 认领
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作者 刘辉 冯海盈 +3 位作者 孙钦密 徐元博 李龙 张立银 《工具技术》 2021年第2期87-90,共4页
本文针对三角测量法激光位移传感器的非线性误差产生原理进行了分析,并提出了误差建模算法。通过建模可实现误差的实时估计,并代入传感器测量值中对误差进行补偿,从而达到提升传感器测量精度的目的。提出了对应的误差测量方法,并对误差... 本文针对三角测量法激光位移传感器的非线性误差产生原理进行了分析,并提出了误差建模算法。通过建模可实现误差的实时估计,并代入传感器测量值中对误差进行补偿,从而达到提升传感器测量精度的目的。提出了对应的误差测量方法,并对误差进行了实验测量和建模,对模型补偿效果进行了验证,结果表明,通过补偿能够大幅提升传感器的检测精度。 展开更多
关键词 激光位移传感器 非线性误差 建模 误差补偿
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