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Spatio-temporal dynamics of cyanobacterial abundance and toxicity in a Mediterranean hypereutrophic lake

海洋湖沼学报(英文) 2023年第5期41卷 1834-1848页

作者： Salah ARIF Nawel DJEBBARI Saber BELHAOUES hassen touati Mourad BENSOUILAH Eco-biology Laboratory for Marine Environments and Coastal Areas Faculty of SciencesMarine Sciences DepartmentUniversity of Badji MokhtarAnnaba 23000Algeria

The Mediterranean basin is considered one of the most vulnerable areas in the world under the impacts of global warming and changes in precipitation ***,a shallow and polymictic freshwater lake located in northeastern Algeria(36°50′N,08°23′E),has recently experienced a significant proliferation of harmful cyanobacteria resulting in the generation of *** carried out this study in order to understand the succession patterns of dominant cyanobacteria and cyanotoxin production and the factors driving this in Oubeira Lake.A total of 26 cyanobacterial genera were identified,and among them Microcystis and Planktothrix accounted for more than 60%of the overall cell *** summer/fall period was dominated by Microcystis,Planktothrix,and in lesser extend by Cylindrospermum,*** the fall/winter transition,Dolichospermum,Pseudanabaena,and Aphanizomenon were the dominant ***,the bloom-forming cyanobacteria showed significant differences between months but not between *** microcystins(MC-LR)was detected in all collected samples(0.62-and 19.14-μg MC-LR equivalent/L),but appeared in high concentrations throughout the period of dominance of Microcystis and *** was more sensitive to nutrients than to *** was more dependent on temperature than on nutrients,which explains their coexistence during summer-fall ***,both genera are positively correlated with MC-LR and would probably be the main producers of ***,Dolichospermum,and Aphanizomenon co-occurred at the end of Planktothrix dominance period(December).Aphanizomenon and Pseudanabaena were correlated negatively with temperature and positively with water *** showed a strong positive correlation with *** Lake,could serve as a model of how cyanobacteria blooms may develop in lakes within Mediterranean climates.

关键词： Oubeira Lake cyanobacteria microcystin spatiotemporal variations shallow hypereutrophic lake

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Optimizing Deep Learning for Computer-Aided Diagnosis of Lung Diseases: An Automated Method Combining Evolutionary Algorithm, Transfer Learning, and Model Compression

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2519-2547页

作者： hassen Louati Ali Louati Elham Kariri Slim Bechikh College of Information Technology Kingdom UniversityRiffa40434Bahrain SMART Lab University of TunisISGTunisTunisia Department of Information Systems College of Computer Engineering and SciencesPrince Sattam bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia

Recent developments in Computer Vision have presented novel opportunities to tackle complex healthcare issues,particularly in the field of lung disease *** promising avenue involves the use of chest X-Rays,which are commonly utilized in *** fully exploit their potential,researchers have suggested utilizing deep learning methods to construct computer-aided diagnostic ***,constructing and compressing these systems presents a significant challenge,as it relies heavily on the expertise of data *** tackle this issue,we propose an automated approach that utilizes an evolutionary algorithm(EA)to optimize the design and compression of a convolutional neural network(CNN)for X-Ray image *** approach accurately classifies radiography images and detects potential chest abnormalities and infections,including ***,our approach incorporates transfer learning,where a pre-trainedCNNmodel on a vast dataset of chest X-Ray images is fine-tuned for the specific task of detecting *** method can help reduce the amount of labeled data required for the task and enhance the overall performance of the *** have validated our method via a series of experiments against state-of-the-art architectures.

关键词： Computer-aided diagnosis deep learning evolutionary algorithms deep compression transfer learning

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Intersubband transitions in In_xAl_(1-x)N/In_yGa_(1-y)N quantum well operating at 1.55 μm

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Chinese Physics B 2014年第9期23卷 394-398页

作者： hassen Dakhlaoui Department of Physics College of Science for Girls

In this paper, we theoretically study the effects of doping concentration ND and an external electric field on the intersubband transitions in InxAl（l-x）N/InyGa（l-y）N single quantum well by solving the Schrodinger and Poisson equations self-consistently. Obtained results including transition energies, the band structure, and the optical absorption have been discussed. The lowest three intersubband transitions （E2 -El）, （E3 -El）, and （E3 -E2） are calculated as functions of doping concentration ND. By increasing the doping concentration ND, the depletion effect can be reduced, and the ionized electrons will compensate the internal electric field which results from the spontaneous polarization. Our results show that an optimum concentration ND exists for which the transition 0.8 eV （1.55 μm） is carried out. Finally, the dependence of the optical absorption α13（ω） on the external electric field and doping concentration is studied. The maximum of the optical absorption can be red-shifted or blue-shifted through varying the doping concentration and the external electric field. The obtained results can be used for designing optical fiber telecommunications operating at 1.55 μm.

关键词： intersubband transition delta doping InGaN/GaN quantum well

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Quantum Size and Doping Concentration Effects on the Current-Voltage Characteristics in GaN Resonant Tunneling Diodes

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Chinese Physics Letters 2013年第7期30卷 185-188页

作者： hassen Dakhlaoui Department of Physics College of Science for GirlsDammam 31113Saudi Arabia

We theoretically investigate the effects of quantum size and doping concentration on the current-voltage characteristics of GaN resonant tunneling *** results show a marked dependence of the peak current density on the emitter and collector spacers,and the existence of some thickness in the emitter,for which the electric current density reaches its maximum with a large peak-to-valley *** also study the effect of the doping concentration in the emitter and collector *** is found that the doping concentration can greatly affect the current-voltage *** particular,it increases the peak of the current density and displaces the position of the maxima of the current dependence on the applied bias *** effects of aluminum concentration and temperature are also ***,it is demonstrated that it is possible to have a symmetrical current for applying bias voltage in both directions by adjusting the thickness of the collector spacer.

关键词： doping Tunnel Quantum

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On a Ginzburg-Landau Type Energy with Discontinuous Constraint for High Values of Applied Field

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Chinese Annals of Mathematics,Series B 2011年第1期32卷 15-26页

作者： hassen AYDI Université de Monastir Institut Supérieur d'Informatique de MahdiaKm 4Réjiche5121 MahdiaTunisie

In the presence of applied magnetic fields H such that |lnε|《H《1/ε2,the author evaluates the minimal Ginzburg-Landau energy with discontinuous *** expression is analogous to the work of Sandier and Serfaty.

关键词： Ginzburg-Landau functional Mixed phase Discontinuous constraint

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An Integrated Multilayered Framework for IoT Security Intrusion Decisions

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Intelligent Automation & Soft Computing 2023年第4期36卷 429-444页

作者： hassen Sallay Umm Al-Qura University Makkah225400KSA

Security breaches can seriously harm the Internet of Things(IoT)and Industrial IoT(IIoT)*** damage can exceedﬁnancial and material losses to threaten human *** these security risks is challenging given IoT ubiquity,complexity,and restricted *** intrusion man-agement is a cornerstone in fortifying the defensive security *** paper presents an integrated multilayered framework facilitating the orchestration of the security intrusion management process and developing security decision support *** proposed framework incorporates four layers with four dedicated processing *** paper focuses mainly on the analytical *** present the architecture and models for predictive intrusion analytics for reactive and proactive defense *** differentiate between the device and network levels to master the complexity of IoT ***ﬁting from the singu-larity of IIoT devices trafﬁc,we approach the reactive security intrusion predic-tion through outlier detection models *** thoroughly experiment with ten outlier detection models on the IIoT wustl realistic *** obtained results show the adequacy of the approach with an area under the curve(AUC)results surpassing 98%for several models with a good level of precision and time efﬁ-***,we investigate the use of survival analysis semi-parametric predictive models to forecast the security intrusion before its occurrence for the proactive security *** experiments show encouraging results with a con-cordance index(c-Index)reaching 89%and an integrated brier score(IBS)of *** integrating outlier intrusion detection and survival forecasting,the fra-mework provides a valuable means to monitor the security intrusions in IoT.

关键词： IoT intrusion framework outlier detection survival analysis

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Velocity gradient elasticity for nonlinear vibration of carbon nanotube resonators

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1520-1530页

作者： Hamid MSEDIGHI hassen MOUAKAD Mechanical Engineering Deparment Faculty of Engineering Shahid Chamran University of AhvazAhvaz ***Iran Driling Center of Exellence and Research Center Shahid Chamran University of AhvazAhvaz ***Iran Mechanical and Industrial Engineering Department Collge of EngineeringSultan Qaboos UniversitMuscalOMAN

In this study,for the first time,we investigate the nonlocality superimposed to the size effects on the nonlinear dynamics of an electrically actuated single-walled carbon-nanotube-based *** undertake two models to capture the nanostructure nonlocal size effects:the strain and the velocity gradient *** use a reduced-order model based on the differential quadrature method(DQM)to discretize the goverming nonlinear equation of motion and acquire a discretized-parameter nonlinear model of the *** structural nonlinear behavior of the system assuming both strain and velocity gradient theories is investigated using the discretized *** results suggest that nonlocal and size effects should not be neglected because they improve the prediction of corresponding dynamic amplitudes and,most importantly,the critical resonant frequencies of such *** these effects may impose a considerable source of error,which can be amended using more accurate modeling techniques.

关键词： velocity gradient elasticity theory nanotube resonators differential-quadrature method nonlinear vibration

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Experimental and theoretical investigations of the lateral vibrations of an unbalanced Jeffcott rotor

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Frontiers of Structural and Civil Engineering 2020年第4期14卷 1024-1032页

作者： Ali ALSALEH Hamid MSEDIGHI hassen MOUAKAD Saudi Arabian Oil Company(ARAMCO) Dhahran 31311Saudi Arabia Mechanical Engineering Deparment Faculty of EngineeringShahid Chamran University of AhvazAhvaz 61357-43337Iran Drilling Center of Excellence and Research Shahid Chamran University of AhvazAhvaz 61357-43337Iran Mechanical and Industrial Engineering Deparment Sultan Qaboos UniversinAI Khoudh MuscatOman

The current work experimentally explores and then theoretically examines the lateral vibrations of an unbalanced Jeffcott rotor-system working at several unbalance *** this end,three conditions of eccentric masses are considered by using a Bently Nevada RK-4 rotor *** of the steady-state as well as the startup data at rigid and flexible rotor states are captured by conducting a setup that mimics the vibration monitoring industrial *** linear governing equation of the considered rotor is extracted by adopting the Lagrange method on the basis of rigid rotor assumptions to theoretically predict the lateral *** dynamic features of the rotor system such as the linearized bearing induced stiffness are exclusively acquired from startup *** is demonstrated that,with an error of less than 5%,the proposed two-degrees-of-freedom model can predict the flexural vibrations at rigid *** at flexible condition,it fails to accurately predict the dynamic *** contrast to the other works where nonlinear mathematical models with some complexities are proposed to mathematically model the real systems,the present study illustrates the applicability of employing simple models to predict the dynamic response of a real rotor-system with an acceptable accuracy.

关键词： rotor-dynamics Jeffcott rotor lateral vibrations Lagrange method system-equivalent stfess sleeve bearings il film induced stiffness

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Effect of Si δ-Doping on the Linear and Nonlinear Optical Absorptions and Refractive Index Changes in InAlN/GaN Single Quantum Wells

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Chinese Physics Letters 2016年第2期33卷 102-105页

作者： Shaffa Almansour hassen Dakhlaoui Emane Algrafy Department of Physics College of Science for GirlsUniversity of Dammam

In the framework of effective mass approximation, we theoretically investigate the electronic structure of the Si δ-doped InAIN/GaN single quantum well by solving numerically the coupled equations Schrodinger-Poisson self-consistently. The linear, nonlinear optical absorption coefficients and relative refractive index changes are calculated as functions of the doping concentration and its thickness. The obtained results show that the position and the amplitude of the linear and total optical absorption coefficients and the refractive index changes can be modified by varying the doping concentration and its thickness. In addition, it is found that the maximum of the optical absorption can be red-shifted or blue-shifted by varying the doping concentration. The obtained results are important for the design of various electronic components such as high-power FETs and infrared photonic devices.

关键词： of is In GaN in Doping on the Linear and Nonlinear Optical Absorptions and Refractive Index Changes in InAlN/GaN Single Quantum Wells on

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Weinstein–Sobolev Spaces of Exponential Type and Applications

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Acta Mathematica Sinica,English Series 2013年第3期29卷 591-608页

作者： hassen BEN MOHAMED Belgacem GHRIBI Department of Mathematics Faculty of Sciences of Gabs

In this paper, we introduce and study the Sobolev spaces of exponential type associated with the Weinstein operator, via some elements of harmonic analysis related to this operator. In particular, some properties, including completeness and imbedding theorem, are proved. Finally, using the theory of reproducing kernels, some applications are given for these spaces.

关键词： Weinstein operator Weinstein transform distribution Sobolev spaces

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