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Characteristics of Extreme Rainfall Events over Uganda during September to November Rainfall Season

Journal of Geoscience and Environment Protection 2024年第3期12卷 131-152页

作者： Donnata Alupot Guirong Tan Kokou Romaric Posset Peter Natiko Key laboratory of Meteorological Disaster Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD) Nanjing University of Information Science and Technology Nanjing China Climate Change Department Pan African University Institute for Water and Energy Sciences (Including Climate Change) C/O Univer-sité Abou Bekr Belkaid Tlemcen Campus Chetouane Tlemcen Algeria Directorate of Weather Forecasting Uganda National Meteorological Authority Port Bell Road Kampala Uganda

Understanding the characteristics of extreme rainfall is crucial for effective flood management planning, as it enables the incorporation of insights from past extreme rainfall patterns and their spatiotemporal distribution. This work investigated the changes in the frequency and pattern of extreme rainfall over Uganda, using daily datasets sourced from Climate Hazard Group InfraRed Precipitation with Station (CHIRPS-v2) for the period 1981 to 2022. The study utilized the extreme weather Indices provided by the Expert Team on Climate Change Detection and Indices (ETCCDI). Attention was directed towards September to November (SON) rainfall season with precise analysis of four indices (Rx1day, Rx5day, R95p, and R99p). The Sequential Mann-Kendall (SQMK) non-parametric test was applied to identify abrupt changes in SON extreme rainfall trends. Results showed that October consistently recorded the highest count of extreme rainfall days across all four indices. The long-term analysis revealed fluctuations in extreme rainfall events across years, with certain periods exhibiting heightened intensity. The analysis portrayed a shift in the decadal variations and region-specific distribution of extreme rainfall, with Eastern Uganda and areas around Lake Victoria standing out compared to other regions. The findings further revealed an increase in extreme rainfall for all indices in the recent decade (2011-2022) with 2019/2020 standing out as the extreme years of SON for the study period. While trendlines suggested a slight increase in intense daily rainfall events, the SQMK tests revealed statistical significance in the trend of prolonged periods of intense daily rainfall. This study contributes to the understanding of the spatiotemporal variability and trends of extreme rainfall events over Uganda during the SON season, which is crucial for the assessment of climate change impacts and adaptation strategies. It provides valuable information for seasonal extreme rainfall forecas

关键词： CHIRPS Variability Region-Specific Early Warning Climate Change

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Overall Assessment of Heat Transfer for a Rarefied Flow in a Microchannel with Obstacles Using Lattice Boltzmann Method

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工程与科学中的计算机建模(英文) 2024年第1期138卷 273-299页

作者： Siham Hammid Khatir Naima Omolayo M.Ikumapayi Cheikh Kezrane Abdelkrim Liazid Jihad Asad Mokdad Hayawi Rahman Farhan Lafta Rashid Naseer Ali Hussien Younes Menni laboratory of Development in Mechanics and Materials(LDMM) Zian Achour UniversityDjelfaPB 3117Algeria Department of Technology University Center Salhi Ahmed Naama(Ctr.Univ.Naama)P.O.Box 66Naama45000Algeria Department of Mechanical and Mechatronics Engineering Afe Babalola University Ado Ekiti360101Nigeria Departement of Physics Faculty of ScienceAbou Bekr Belkaid UniversityTlemcen13000Algeria Department of Physics Faculty of Applied SciencesPalestine Technical University-KadoorieTulkarmPalestine Aeronautical Technical Engineering Al-Farahidi UniversityBaghdad10011Iraq Mechanical Engineering Department University of KerbalaKarbala56001Iraq Information and Communication Technology Research Group Scientific Research CenterAl-Ayen UniversityThi-QarIraq National University of Science and Technology Dhi QarIraq

The objective of this investigation is to assess the effect of obstacles on numerical heat transfer and fluid flow momentum in a rectangular microchannel(MC).Two distinct configurations were studied:one without obstacles and the other with alternating obstacles placed on the upper and lower *** research utilized the thermal lattice Boltzmann method(LBM),which solves the energy and momentum equations of fluids with the BGK approximation,implemented in a Python coding *** jump and slip velocity conditions were utilized in the simulation for the MC and extended to all obstacle *** study aims to analyze the rarefaction effect,with Knudsen numbers(Kn)of 0.012,0.02,and *** outcomes indicate that rarefaction has a significant impact on the velocity and temperature *** presence of nine obstacles led to slower fluid movement inside the microchannel MC,resulting in faster cooling at the *** MCs with obstacles,the rarefaction effect plays a crucial role in decreasing the Nusselt number(Nu)and skin friction coefficient(Cf).Furthermore,the study demonstrated that the obstacles played a crucial role in boosting fluid flow and heat transfer in the *** findings suggest that the examined configurations could have potential applications as cooling technologies in micro-electro-mechanical systems and microdevice applications.

关键词： Microfluid rarefied flow LBM microchannel Knudsen number numerical simulation

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Whittle’s Index Based Sensor Scheduling for Multiprocess Systems Under DoS Attacks

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Journal of Systems Science & Complexity 2024年第1期37卷 329-350页

作者： CAI Zai DING Kemi Shenzhen Key laboratory of Control Theory and Intelligent Systems Southern University of Science and TechnologyShenzhen 518055China.

In this paper,the authors consider how to design defensive countermeasures against DoS attacks for remote state estimation of multiprocess *** each system,a sensor will measure its state and transmits the data packets through an unreliable channel which is vulnerable to be jammed by an *** limited communication bandwidth,only a subset of sensors are allowed for data transmission,and how to select the optimal one to maximize the accuracy of remote state estimation is the focus of the proposed *** authors first formulate this problem as a Markov decision process and investigate the existence of optimal ***,the authors demonstrate the piecewise monotonicity structure of optimal *** the difficulty of obtaining an optimal policy of large-scale problems,the authors develop a suboptimal heuristic policy based on the aforementioned policy structure and Whittle’s ***,a closed form of the indices is derived in order to reduce implementation complexity of proposed scheduling policy and numerical examples are provided to illustrate the proposed developed results.

关键词： DoS attacks Kalman filter remote state estimation Whittle’s index.

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Effect of Velocity Ratio,Viscosity Ratio,Contact Angle,and Channel Size Ratio on Droplet Formation

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Fluid Dynamics & Materials Processing 2023年第10期19卷 2471-2480页

作者： Mohammed Bourega Ibrahim Kromba Khadidja Feah Arbi Soﬁane Souimane Biomedical Engineering laboratory Abu Bakr Belkaid UniversityTlemcen13000Algeria

This study uses a T-junction to examine the effects of different parameters(velocity ratio,viscosity,contact angle,and channel size ratio)on the generation of microdroplets,related rate,and *** speciﬁcally,numerical simulations are exploited to investigate situations with a velocity varying from 0.004 to 1.6 m/s for the continuous phase and from 0.004 to 0.8 m/s for the dispersed phase,viscosity ratios(0.668,1,6.689,10,66.899),contact angle 80°<θ<270°and four different canal size ratios(1,1.5,2 and 4).The results show that canal size inﬂuences droplet size and the generation *** contact angle has an impact on the form and the quality of generated ***,the relationship between velocity and viscosity ratios,droplet size,and generation rate is non-monotonic.

关键词： Microﬂuidics T-junction droplet generator droplet size droplet diameter generation rate

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Analysis of Coupled Surface Plasmon in LHM Mediated Dielectric Gap Multilayer Structure

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Photonic Sensors 2020年第2期10卷 113-122页

作者： Mohammed BENDJEBBOUR Abdellatif CHERIFI Benamar BOUHAFS University of tlemcen Faculty of SciencesTheoretical Physics LaboratoryTlemcen 13000Algeria

The purpose of this work is to investigate theoretically the characteristics of confined electromagnetic modes propagating along the interfaces of a multilayer *** one dimensional(1D)sensor is formed by stacking a left-handed material(LHM)layer between a SiO2-glass prism and a dielectric gap layer in contact with gold(Au).The results indicate that the total thickness of the LHM layer and dielectric gap,in optimum conditions,give the ability of tuning significantly the characteristics of the resonant modes correlated to surface plasmons(SPs)propagation along the interfaces of the designed *** considering two arrangements between LHM and Au,two opposite resonant behaviors observed in p-reflectance spectra are analyzed in the angular interrogation mode and discussed thoroughly.

关键词： Confined electromagnetic modes surface plasmon resonance sensor left-handed material

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Potential of SPR Sensors Based on Multilayer Interfaces With Gold and LHM for Biosensing Applications

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Photonic Sensors 2017年第3期7卷 199-205页

作者： Abdellatif CHERIFI Benamar BOUHAFS University of tlemcen Theoretical Physics Laboratory Physics of Department Tlemcen 13000 Algeria

Recently, the subject on ＂plasmonics＂ has received significant attention in designing surface plasmon resonance （SPR） sensors. In order to achieve extremely high-sensitivity sensing, multilayered configurations based on a variety of active materials and dielectrics have been exploited. In this work, a novel SPR sensor is proposed and investigated theoretically. The structure, analyzed in attenuated total reflection （ATR）, consists of multilayer interfaces between gold and a metamaterial （LHM） separated by an analyte layer as a sensing medium. By interchanging between gold and LHM, under the effect of the refractive index （RI） of analyte set to be in the range of 1.00 to 1.99, the sharp peak reflectivity at the SPR angle takes two opposite behaviors predicted from the transfer matrix method. At the threshold value of 1.568 of the refractive index of analyte and when the LHM is the outer medium, the layered structure exhibits a giant sharp peak located at 43° of intensity up to 105 due to the Goos-Hanchen effect. With respect to the refractive index （RI） change and thickness of analyte, the characteristics （intensity, resonance condition, and quality factor） of the SPR mode, which make the proposed device have the potential for biosensing applications, have been analytically modelized.

关键词： Plasmonic goos-Hhnchen (GH) effect SPR sensor systems sub-wavelength scale

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A new correlation-based approach for ensemble selection in random forests

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International Journal of Intelligent Computing and Cybernetics 2021年第2期14卷 251-268页

作者： Mostafa El Habib Daho Nesma Settouti Mohammed El Amine Bechar Amina Boublenza Mohammed Amine Chikh Biomedical Engineering laboratory University of TlemcenTlemcenAlgeria

Purpose-Ensemble methods have been widely used in the field of pattern recognition due to the difficulty offinding a single classifier that performs well on a wide variety of *** the effectiveness of thesetechniques,studies have shown that ensemble methods generate a large number of hypotheses and thatcontain redundant classifiers in most *** works proposed in the state of the art attempt to reduce allhypotheses without affecting ***/methodology/approach-In this work,the authors are proposing a pruning method that takes intoconsideration the correlation between classifiers/classes and each classifier with the rest of the *** authorshave used the random forest algorithm as trees-based ensemble classifiers and the pruning was made by atechnique inspired by the CFS(correlation feature selection)***-The proposed method CES(correlation-based Ensemble Selection)was evaluated onten datasets from the UCI machine learning repository,and the performances were compared to sixensemble pruning *** results showed that our proposed pruning method selects a smallensemble in a smaller amount of time while improving classification rates compared to the ***/value-CES is a new ordering-based method that uses the CFS *** selects,in a shorttime,a small sub-ensemble that outperforms results obtained from the whole forest and the other state-of-thearttechniques used in this study.

关键词： Ensemble pruning Random forest Tree selection Correlation CFS CES

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The Radiation Loss of a Cylindrical Methane-Argon Plasma Arc

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Plasma Science and Technology 2010年第2期12卷 218-223页

作者： B.LIANI R.BENALLAL M.LEMERINI Theoretical Physics laboratory Sciences Faculty University of Tlemcen

Calculation of the net radiation emitted by a CH4-Ar mixture, in a temperature range of 5,000-30,000 K with the assumption of local thermodynamic equilibrium （LTE）, is conducted. Continuum and line emissions are taken into account. The radiative transfer of each line is calculated by means of an escape factor depending on the shape and broadening of the line. Assuming a cylindrical, homogeneous, and isothermal plasma, the net emission coefficient is calculated for different pressures between 1 atm and 10 atm and arc radia of 0 mm to 1 mm. Results show that the argon presence in the CH4-Ar mixture has a significant effect on the total radiation emitted for the temperature above 17,000 K and the results for pure argon agree with those of BAUDER and EVANS.

关键词： thermal plasma methane argon radiation loss radiative transfer equation

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Numerical inversion method for the Laplace transform based on Boubaker polynomials operational matrix

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International Journal of Modeling, Simulation, and Scientific Computing 2022年第1期13卷 251-264页

作者： Rachid Belgacem Ahmed Bokhari Salih Djilali Sunil Kumar Faculty of Exact and Computer Sciences Mathematic Department Hassiba Benbouali UniversityChlefAlgeria laboratory of Mathematics and its Applications(LMA)Faculty of Exact and Computer Sciences Hassiba Benbouali University ChlefAlgeria Laboratoire d’Analyse Non Lineaire et Mathematiques Appliquees Universite de tlemcen TlemcenAlgeria Department of Mathematics National Institute of Technology Jamshedpur 831014JharkhandIndia

We investigate through this research the numerical inversion technique for the Laplace transforms cooperated by the integration Boubaker polynomials operational *** efficiency of the presented approach is demonstrated by solving some differential ***,this technique is combined with the standard Laplace Homotopy Per-turbation *** numerical results highlight that there is a very good agreement between the estimated solutions with exact solutions.

关键词： Laplace transform Boubaker polynomials operational matrix homotopy per-turbation method numerical method

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Asian Pacific Journal of Tropical Biomedicine 2016年第8期6卷 720-726页

作者： Amina Hoceini Nihel Klouche Khelil Ilhem Ben-Yelles Amine Mesli Sara Ziouani Lotfi Ghellai Nadia Aissaoui Fatima Nas Mounia Arab laboratory of Applied Microbiology in Food Biomedical and Environment Department of Biology Faculty of Nature and Life University of Tlemcen laboratory of Experimental Surgery Dental Surgery Department Faculty of Medicine University of Tlemcen laboratory of Applied Molecular Biology and Immunology Department of Biology University of Tlemcen

Objective: To compare oral hygiene practices, education and social background, food intake and oral malodor of Algerian adults suffering from dental caries with normal controls, and to determine and compare the bacterial composition of the supragingival plaques from the above-mentioned ***: Participants completed a questionnaire and were clinically examined for dental caries using decayed, missing and filled teeth index according to the criteria laid down by the World Health Organization. Supragingival plaque samples were collected from 50 caries-free adults(CF) and 50 caries-active adults(CA). Standard procedures of culture and identification of aerobic and anaerobic bacteria were used. Data were analyzed using Chi-square ***: A total of 117 bacterial strains were isolated from supragingival plaques in CF group subjects, 76(64.96%) of them belonged to 9 aerobic genera, and 41(35.04%) to 9anaerobic genera(P < 0.05). While in the second group, 199 strains were isolated, 119(59.80%) of the strains belonged to 10 aerobic genera and 80(40.20%) to 10 anaerobic bacteria(P < 0.05). Streptococcus mutans, Enterococcus faecium, Aerococcus viridans,Actinomyces meyeri, Lactobacillus acidophilus and Eubacterium limosum showed a significantly higher prevalence in the CA group(P < 0.05). The findings revealed that CA group had a high sugar intake(80%). A significantly higher frequency of tooth brushing(P < 0.000) and a significantly less self-reported oral malodor(P < 0.000) and tooth pain(P < 0.000) were found in CF group, while there was no association of socioeconomic levels and intake of meal snacks with dental ***: This study confirms the association of some aciduric bacteria with caries formation, and a direct association of sugar intake and cultural level with dental ***, oral hygiene practices minimize the prevalence of tooth decay.

关键词： Supragingival plaque Caries-free Caries-active Bacterial composition Algerian adults Cultural level Food intake

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