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Dynamical Behavior and Sensitivity analysis of a Delayed Coronavirus Epidemic Model

Computers, Materials & Continua 2020年第10期65卷 225-241页

作者： Muhammad Naveed Dumitru Baleanu Muhammad Rafiq Ali Raza Atif Hassan Soori Nauman Ahmed Department of Mathematics Air UniversityIslamabadPakistan Department of Mathematics Cankaya UniversityAnkara06530Turkey Department of Medical Research China Medical University HospitalChina Medical UniversityTaichungTaiwan Institute of Space Sciences Magurele-BucharestRomania Faculty of Engineering University of Central PunjabLahorePakistan Department of Mathematics National College of Business Administration and EconomicsLahorePakistan Department of Mathematics and Statistics The University of LahoreLahorePakistan

Mathematical delay modelling has a significant role in the different disciplines such as behavioural,social,physical,biological engineering,and bio-mathematical *** present work describes mathematical formulation for the transmission mechanism of a novel coronavirus(COVID-19).Due to the unavailability of vaccines for the coronavirus worldwide,delay factors such as social distance,quarantine,travel restrictions,extended holidays,hospitalization,and isolation have contributed to controlling the coronavirus *** have analysed the reproduction number and its sensitivity to ***,R_(covid)>1then this situation will help to eradicate the disease and if,R_(covid)>1 the virus will spread rapidly in the human ***-known theorems such as Routh Hurwitz criteria and Lasalle invariance principle have presented for *** local and global stabilizes for both equilibria of the model have also been ***,we have analysed the effect of delay reason on the reproduction *** the last,some very useful numerical consequences have presented in support of hypothetical analysis.

关键词： Coronavirus(COVID-19) delay mathematical model reproduction number sensitive analysis stability analysis

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Effect of the spectrally selective features of the cover and emitter combination on radiative cooling performance

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能源与人工环境(英文) 2021年第3期2卷 251-259页

作者： Mingke Hu Suhendri Bin Zhao Xianze Ao Jingyu Cao Qiliang Wang Saffa Riffat Yuehong Su Gang Pei Department of Architecture and Built Environment University of NottinghamUniversity ParkNottingham NG72RDUK Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230027China Department of Building Services Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina

Radiative cooling(RC)shows good potential for building energy saving by throwing waste heat to the cosmos in a passive and sustainable ***,most available radiative coolers suffer from low cooling *** situation becomes even deteriorated in the daytime when radiative coolers are exposed to direct *** tackle this challenge,an idea of employing both a spectrally selective cover and a spectrally selective emitter is proposed in this study as an alternative approach.A comparative study is conducted among four RC modules with different spectral characteristics for the demonstration of how the spectral profiles of the cover and the emitter affects the RC *** results under given conditions show that the RC module with a spectrally selective cover and a spectrally selective emitter(SC/SE)reaches a net RC power of 62.4 W/m^(2)when the solar radiation is 800 W/m^(2),which is about 1.8 times that of the typical RC module with a spectrally non-selective cover and a spectrally selective emitter(n-SC/SE).When the ambient temperature is 30°C,the SC/SE based RC module realizes a daytime sub-ambient temperature reduction of 20.0°C,standing for a further temperature decrement of 9.2°C compared to the n-SC/SE based RC module.

关键词： Radiative cooling Sky cooling Spectral selectivity sensitive analysis Cover Solar energy

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Fractured reservoir history matching improved based on artificial intelligent

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Petroleum 2016年第4期2卷 344-360页

作者： Sayyed Hadi Riazi Ghasem Zargar Mehdi Baharimoghadam Bahman Moslemi Ebrahim Sharifi Darani Department of Petroleum Engineering Petroleum University of Technology(PUT)AhwazIran Department of Reservoir Evaluation National Iranian South Oil Company(NISOC)AhwazIran

In this paper,a new robust approach based on Least Square Support Vector Machine(LSSVM)as a proxy model is used for an automatic fractured reservoir history *** proxy model is made to model the history match objective function(mismatch values)based on the history data of the *** model is then used to minimize the objective function through Particle Swarm Optimization(PSO)and Imperialist Competitive Algorithm(ICA).In automatic history matching,sensitive analysis is often performed on full simulation *** this work,to get new range of the uncertain parameters(matching parameters)in which the objective function has a minimum value,sensitivity analysis is also performed on the proxy *** applying the modified ranges to the optimization methods,optimization of the objective function will be faster and outputs of the optimization methods(matching parameters)are produced in less time and with high *** procedure leads to matching of history of the field in which a set of reservoir parameters is *** final sets of parameters are then applied for the full simulation model to validate the *** obtained results show that the present procedure in this work is effective for history matching process due to its robust dependability and fast convergence *** to high speed and need for small data sets,LSSVM is the best tool to build a proxy *** the comparison of PSO and ICA shows that PSO is less time-consuming and more effective.

关键词： Proxy model LSSVM PSO ICA sensitive analysis

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Optimum Design of Highway Excavation Slope Angle: Evidence from Dawu Section of Jingzhu Highway

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Journal of China University of Geosciences 2001年第3期12卷 258-260页

作者： Hu XinliEngineering Faculty, China University of Geosciences, Wuhan 430074 Construction Engineering Faculty, Jilin University, Changchun 130026Tang HuimingEngineering Faculty, China University of Geosciences, Wuhan 430074 Engineering Faculty China University of Geosciences Wuhan 430074 Engineering Faculty China University of Geosciences Wuhan 430074 Construction Engineering Faculty Jilin University Changchun 130026

The optimum design of the highway excavation slope angle is one of the most important problems to the highway construction and to the slope improvement. The Dawu Section of Jingzhu (Beijing Zhuhai) Highway is taken as an example to illustrate the study method for excavation slope angle design. The analysis of the engineering condition from different angles with different factors shows that the stability of the slope is calculated by using residual pushing force and the Sarma method. Then the sensitive analysis of the slope stability is conducted by using residual pushing force method. Finally, the optimum angle of design is presented on the precondition of ensuring the whole stability of slope and the economic reasonability. The study results show that the most sensitive factors are the shear strength parameter and the seismic force, and that the optimum excavation slope angle is 60°.

关键词： the most dangerous sliding plane stability evaluation sensitive analysis optimum design angle of slope.

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Defining a Standard Methodology to Obtain Optimum WRF Configuration for Operational Forecast: Application over the Port of Huelva (Southern Spain)

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Atmospheric and Climate Sciences 2016年第2期6卷 329-350页

作者： Raúl Arasa Ignasi Porras Anna Domingo-Dalmau Miquel Picanyol Bernat Codina Mª Ángeles González Jésica Piñón Technical Department Meteosim S.L. Barcelona Spain Department of Astronomy and Meteorology University of Barcelona Barcelona Spain

In this contribution, we calibrate the meteorological model weather and research forecasting (WRF) for operational forecasting in the Port of Huelva managed by the Authority Port of Huelva. Meteorological forecasting will allow reducing the impact of the meteorological phenomena over weather sensitive activities in the region. Concretely, the meteorological modeling developed will be used to analyze meteorological hazard impacts and to improve the management of the local air quality. To achieve these goals, numerous sensitive analyses corresponding to different model options have been developed. These analyses consider different physical and dynamical options, the coupling of very high resolution physiographic database (topography and land uses), and data assimilation. Comparing experiments, results with observational measures provide us by the Spanish National Meteorology Agency (AEMET). During a representative period, the optimum WRF configuration for the region is obtained. Calibration has been focused on wind due to this is the main risk factor in the region. When the model is satisfactorily calibrated, WRF is evaluated using whole modeling years 2012 and 2013, working with very high horizontal resolution, up to 0.333 km of horizontal grid resolution. Results obtained from the evaluation indicate that the numerical weather prediction system developed has a confidence level of 70% for the temperature, 81% and 66% for the wind speed and wind direction respectively, and 90% for the relative humidity. Methodology designed defines the quality control assurance of high-accuracy forecasting services of Meteosim S.L.

关键词： WRF sensitive analysis Meteorological Modelling Physical Options LES High Resolution

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在负信用期允许情况下供应商最优信用期决策

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商贸经济 2008年第12期

作者：郑锦川刘会唐燕

在许多采购活动中，买家被允许经过一段时间后再付货款，而在这段时间内买家并不需要支付任何利息费用，这段时间被称为信用期（credit period）。国内外有许多关于这个问题的研究。然而，如今负信用期逐渐兴起，即供应商先收款后发货... 详细信息

在许多采购活动中，买家被允许经过一段时间后再付货款，而在这段时间内买家并不需要支付任何利息费用，这段时间被称为信用期（credit period）。国内外有许多关于这个问题的研究。然而，如今负信用期逐渐兴起，即供应商先收款后发货，尤其是在网络交易或者供应链中处于强势地位的供应商很多采用了这种方式。文章研究了基于负信用期条件下的供应商最优信用期决策。首先，假设商品的终端需求对价格是敏感的，即其价格需求弹性小于－1。其次，采用Stackelberg模型来界定买家与供应商的关系，即供应商先制定其策略，买家再根据供应商的策略做出反应进而做出自己的决策。然后通过建立模型分别给出供应商提供正信用期和负信用期时供应商和买家为了使得各自利润最大化的决策制定方法。通过数学算例得出供应商做出的最优信用期决策随着条件变化而变化，并通过灵敏度分析，找出影响供应商做出决策的一些重要因素。

关键词：负信用期需求弹性 Stackelberg模型灵敏度分析 negative credit period demand elasticity stackelberg model sensitive analysis

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