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Spatiotemporal variability/stability analysis of NO_(2),CO,and land surface temperature(LST)during COVID-19 lockdown in Amman city,Jordan

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Geo-Spatial Information Science 2023年第3期26卷 540-557页

作者： ali Almagbile Khaled Hazaymeh Department of Geography Applied Geoinformatics LaboratoryYarmouk UniversityIrbidJordan

The massive lockdown of human socioeconomic activities and vehicle movements due to the COVID-19 pandemic in 2020 has resulted in an unprecedented reduction in pollutant gases such as Nitrogen Dioxide(NO_(2))and Carbon Monoxide(CO)as well as Land Surface Temperature(LST)in Amman as well as all countries around the *** this study,the spatial and temporal variability/stability of NO_(2),CO,and LST throughout the lockdown period over Amman city have been *** NO_(2) and CO column density values were acquired from Sentinel-5p while the LST data were obtained from MODIS satellite during the lockdown period from 20 March to 24 April in 2019,2020,and *** statistical analysis showed an overall reduction in NO_(2) in 2020 by around 27% and 48% compared to 2019 and 2021,***,an increase of 7% in 2021 compared to 2019 was observed because almost all anthropogenic activities were allowed during the *** temporal persistence showed almost constant NO2 values in 2020 over the study area throughout the lockdown *** addition,a slight decrease in CO(around 1%)was recorded in 2020 and 2021 compared to the same period in *** on human activities resulted in an evident drop in LST in 2020 by around 13%and 18% less than the 5-year average and 2021 *** study concludes that due to the restrictions imposed on industrial activities and automobile movements in Amman city,an unprecedented reduction in NO_(2),CO,and LST was recorded.

关键词： Air quality COVID-19 lockdown spatiotemporal analysis NO_(2) CO Land Surface Temperature(LST) Sentinel-5p and MODIS satellites

Numerical Prediction of Form Factor and Wave Interference of A Trimaran for Different Outrigger Positions

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China Ocean Engineering 2022年第2期36卷 279-288页

作者： ali DOGRUL Burak YILDIZ Department of Naval Architecture and Marine Engineering Turkish Naval AcademyNational Defense UniversityIstanbul 34940Turkey Department of Marine Engineering Operations Yildiz Technical UniversityIstanbul 34349Turkey

Trimaran hydrodynamics have been an important research topic in recent *** have even been chosen for naval surface *** this case,investigation of a trimaran with different outrigger positions is important and necessary for better hydrodynamic *** paper focuses on the numerical investigation of trimaran *** trimaran model used in this study is a 1/80 scale high-speed displacement frigate-type concept developed by the Center for Innovation in Ship Design(CISD)at Naval Surface Warfare Center,Carderock Division(NSWCCD).The numerical simulations were conducted for different outrigger positions at low and moderate Froude numbers by using commercial CFD software solving URANS equations.A verification and validation study was carried out for the numerical method in one configuration and one ship *** existing experimental results for the trimaran resistance in the literature were used for *** different outrigger positions were analyzed and the form factor of each configuration was calculated by the Prohaska *** total resistance was decomposed to its components using the form *** interference factor was calculated for each configuration in terms of total resistance,residual resistance and wave ***,wave profiles using the longitudinal wave cuts in different locations were obtained both numerically and *** was concluded that the outrigger position had different effects on the interference,total resistance and wave profile at different Froude *** was also shown that the CFD results were in good agreement with the experimental data in all *** conclusion,this study presents the results of interference effects for different trimaran configurations in terms of wave resistance in addition to the total resistance and residual *** numerical method was validated not only with the total resistance test data but also the longitudinal wave profiles a

关键词： CFD form factor wave interference wave profile outrigger trimaran

Optimal motion cueing algorithm for accelerating phase of manned spacecraft in human centrifuge

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Chinese Journal of Aeronautics 2020年第7期33卷 1991-2001页

作者： ali MAHMOODI Isooda KAZEMI Department of Aerospace Engineering Science and Research BranchIslamic Azad UniversityTehran ***Iran

This paper presents a novel optimal Motion Cueing Algorithm(MCA)to control the rotations of a Human Centrifuge(HC)and achieve the best simulation of a Space Craft(SC)*** of the specific forces sensed by astronauts of the SC and the HC have been derived and linearized.A Linear Quadratic Regulator(LQR)controller is implemented for the problem which tends to minimize the error between the two sensed specific forces as well as control input in a cost *** results in control inputs of the HC to generate its sensed specific force as close as possible to the one in the *** algorithm is implemented for both linearized and nonlinear portions of a US space shuttle mission trajectory as a verification using *** longitudinal direction,the proposed MCA,works well when the acceleration is less than 2 g in which the tracking error does not exceed 12%.In lateral direction the tracking is much better even in nonlinear region since the error remains less than 7%for tilting up to 50°.Finally,the effect of weight matrixes in the LQR cost function on overall weight and power of the HC motion system is discussed.

关键词： Accelerating phase Human centrifuge Manned spacecraft Optimal motion cueing Specific force

Integration of maximum crop response with machine learning regression model to timely estimate crop yield

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Geo-Spatial Information Science 2021年第3期24卷 474-483页

作者： Qiming Zhou ali Ismaeel Department of Geography Hong Kong Baptist UniversityHong KongChina

Timely and reliable estimation of regional crop yield is a vital component of food security assessment, especially in developing regions. The traditional crop forecasting methods need ample time and labor to collect and process field data to release official yield reports. Satellite remote sensing data is considered a cost-effective and accurate way of predicting crop yield at pixel-level. In this study, maximum Enhanced Vegetation Index (EVI) during the crop-growing season was integrated with Machine Learning Regression (MLR) models to estimate wheat and rice yields in Pakistan’s Punjab province. Five MLR models were compared using a fivefold cross-validation method for their predictive accuracy. The study results revealed that the regression model based on the Gaussian process outperformed over other models. The best performing model attained coefficient of determination (R^(2)), Root Mean Square Error (RMSE, t/ ha), and Mean Absolute Error (MAE, t/ha) of 0.75, 0.281, and 0.236 for wheat;0.68, 0.112, and 0.091 for rice, respectively. The proposed method made it feasible to predict wheat and rice 6- 8 weeks before the harvest. The early prediction of crop yield and its spatial distribution in the region can help formulate efficient agricultural policies for sustainable social, environmental, and economic progress.

关键词： Machine learning remote sensing crop yield timely forecast

Impact of nanoparticle shape on thermohydraulic performance of a nanofluid in an enhanced microchannel heat sink for utilization in cooling of electronic components

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Chinese Journal of Chemical Engineering 2021年第12期34卷 36-47页

作者： Mehdi Bahiraei ali Monavari Institute of Research and Development Duy Tan UniversityDa Nang 550000Vietnam Department of Mechanical Engineering Razi UniversityKermanshahIran

In this article,the thermal–hydraulic efficacy of a boehmite nanofluid with various particle shapes is evaluated inside a microchannel heat *** study is done for particle shapes of platelet,cylinder,blade,brick,and oblate spheroid at Reynolds numbers(Re)of 300,800,1300,and *** particle volume fraction is assumed invariant for all of the nanoparticle *** heat transfer coefficient(h),flow irregularities,pressure loss,and pumping power heighten by the elevation of the Re for all of the nanoparticle ***,the nanofluid having the platelet-shaped nanoparticles leads to the greatest h,and the nanofluid having the oblate spheroid particles has the lowest h and smallest pressure *** contrast,the nanofluid having the platelet-shaped nanoparticles leads to the highest pressure *** mean temperature of the bottom surface,thermal resistance,and temperature distribution uniformity decrease by the rise in the Reynolds number for all of the particle ***,the best distribution of the temperature and the lowest thermal resistance are observed for the suspension containing the platelet ***,the thermal resistance of the nanofluid with the platelet particles shows a 9.5%decrement compared to that with the oblate spheroid particles at Re=*** all the nanoparticle shapes,the figure of merit(FoM)uplifts by elevating the Re,while the nanofluids containing the brickand oblate spheroid-shaped nanoparticles demonstrate the highest FoM values.

关键词： Nanofluid Thermohydraulic performance Nanoparticle shape Microchannel heat sink Boehmite nanoparticles

Low Impedance Fault Identification and Classification Based on Boltzmann Machine Learning for HVDC Transmission Systems

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Journal of Modern Power Systems and Clean Energy 2022年第2期10卷 440-449页

作者： Raheel Muzzammel ali Raza the Department of Electrical Engineering University of LahoreLahore 54000Pakistan

Identification and classification of DC faults are considered as fundamentals of DC grid protection.A sudden rise of DC fault current must be identified and classified to immediately operate the corresponding interrupting *** this paper,the Boltzmann machine learning(BML)approach is proposed for identification and classification of DC faults using travelling waves generated at fault point in voltage source converter based high-voltage direct current(VSC-HVDC)transmission *** unsupervised way of feature extraction is performed on the frequency spectrum of the travelling *** class logistic regression(BCLR)classifies the HVDC transmission system into faulty and healthy *** proposed technique reduces the time for fault identification and classification because of reduced tagged data with few ***,the faults near or at converter stations are readily identified and *** performance of the proposed technique is assessed via simulations developed in MATLAB/Simulink and tested for pre-fault and post-fault data both at VSC1 and VSC2,***,the proposed technique is supported by analyzing the root mean square error to show practicality and realization with reduced computations.

关键词： Binary class logistic regression(BCLR) Boltzmann machine learning(BML) DC grid protection fault identification and classification voltage source converter based high-voltage direct current(VSC-HVDC)transmission system

Cache in fog computing design,concepts,contributions,and security issues in machine learning prospective

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Digital Communications and Networks 2023年第5期9卷 1033-1052页

作者： Muhammad ali Naeem Yousaf Bin Zikria Rashid ali Usman Tariq Yahui Meng ali Kashif Bashir School of Science Guangdong University of Petrochemical TechnologyMaoming525000China Department of Information and Communication Engineering Yeungnam UniversityGyeongsan38541Republic of Korea Department of Information and Communication Technologies Universitat Pompeu FabraBarcelonaSpain College of Computer Engineering and Sciences Prince Sattam Bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia Department of Computing and Mathematics Manchester Metropolitan UniversityManchesterUnited Kingdom Woxsen School of Business Woxsen UniversityHyderabadIndia Department of Computer Science and Mathematics Lebanese American UniversityBeirutLebanon

The massive growth of diversified smart devices and continuous data generation poses a challenge to communication *** deal with this problem,communication networks consider fog computing as one of promising technologies that can improve overall communication *** brings on-demand services proximate to the end devices and delivers the requested data in a short *** computing faces several issues such as latency,bandwidth,and link utilization due to limited resources and the high processing demands of end *** this end,fog caching plays an imperative role in addressing data dissemination *** study provides a comprehensive discussion of fog computing,Internet of Things(IoTs)and the critical issues related to data security and dissemination in fog ***,we determine the fog-based caching schemes and contribute to deal with the existing issues of fog ***,this paper presents a number of caching schemes with their contributions,benefits,and challenges to overcome the problems and limitations of fog *** also identify machine learning-based approaches for cache security and management in fog computing,as well as several prospective future research directions in caching,fog computing,and machine learning.

关键词： Internet of things Cloud computing Fog computing Caching Latency

Identification of structural parameters and boundary conditions using a minimum number of measurement points

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1331-1348页

作者： ali KARIMPOUR Salatn RAHMATALLA Department of Civil and Environmental Engineering and Iowa Technology Institute The University of IowaIowa CityIA 52242USA

This article proposes a novel methodology that uses mathematical and numerical models of a structure to build a data set and determine crucial nodes that possess the highest *** surfaces between the structural parameters and structural output features,represented by the natural frequencies of the structure and local transmissibility,are built using the numerical data set.A description of a possible experimental application is provided,where sensors are mounted at crucial nodes,and the natural frequencies and local transmissibility at each natural frequency are determined from the power spectral density and the power spectral density ratios of the sensor responses,*** inverse iterative process is then applied to identify the structural parameters by matching the experimental features with the available parameters in the myriad numerical data *** examples are presented to demonstrate the feasibility and efficacy of the proposed *** results reveal that the method was able to accurately identify the boundary coefficients and physical parameters of the Euler-Bemoulli beam as well as a highway bridge model with elastic foundations using only two measurement *** is expected that the proposed method will have practical applications in the identification and analysis of restored structural systems with unknown parameters and boundary coefficients.

关键词： structural model validation eigenvalue problem response surface inverse problems

Vibration analysis of fluid-conveying multi-scale hybrid nanocomposite shells with respect to agglomeration of nanofillers

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Defence Technology（防务技术） 2021年第1期17卷 212-225页

作者： Farzad Ebrahimi ali Dabbagh Department of Mechanical Engineering Faculty of EngineeringImam Khomeini International UniversityQazvinIran School of Mechanical Engineering College of EngineeringUniversity of TehranTehranIran

The vibration problem of a fluid conveying cylindrical shell consisted of newly developed multi-scale hybrid nanocomposites is solved in the present manuscript within the framework of an analytical *** consistent material is considered to be made from an initial matrix strengthened via both macro-and nano-scale *** influence of nanofillers’agglomeration,generated due to the high surface to volume ratio in nanostructures,is included by implementing Eshelby-Mori-Tanaka homogenization ***,the equivalent material properties of the carbon nanotube reinforced(CNTR)nanocomposite are coupled with those of CFs within the framework of a modified rule of *** the other hand,the influences of viscous flow are covered by extending the Navier-Stokes equation for cylinders.A cylindrical coordinate system is chosen and mixed with the infinitesimal strains of first-order shear deformation theory of shells to obtain the motion equations on the basis of the dynamic form of principle of virtual ***,the achieved governing equations will be solved by Galerkin’s method to reach the natural frequency of the structure for both simply supported and clamped boundary *** a set of illustrations,effects of each parameter on the dimensionless frequency of nanocomposite shells will be shown graphically.

关键词： Vibration Agglomeration effect Multi-scale hybrid nanocomposites Galerkin’s solution Viscous fluid flow