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MEASURES OF WEAK NONCOMPACTNESS AND FIXED POINT THEORY FOR 1-SET WEAKLY CONTRACTIVE OPERATORS ON UNBOUNDED DOMAINS

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Analysis in Theory and Applications 2011年第3期27卷 224-238页

作者： ShaoyuanXu afif ben amar Department of Mathematics and Information TechnologyHanshan Normal UniversityChaozhou 521041 Departement de MathematiquesUniversite de Gafsa Cite Universitaire Zarrouk Faculte des Sciences de Gafsa2112 Gafsa Tunisie

The main purpose of this paper is to prove a collection of new fixed point theorems and existence theorems for the nonlinear operator equation F（x） = αx （α≥〉 1） for so-called 1-set weakly contractive operators on unbounded domains in Banach spaces. We also introduce the concept of weakly semi-closed operator at the origin and obtain a series of new fixed point theorems and the existence theorems for the nonlinear operator equation F（x） = αx （α≥1） for such class of operators. As consequences, the main results general- ize and improve the relevant results, which are obtained by O＇Regan and A. ben amar and M. Mnif in 1998 and 2009 respectively. In addition, we get the famous fixed point theorems of Leray-Schauder, Altman, Petryshyn and Rothe type in the case of weakly sequentially continuous, 1-set weakly contractive （μ-nonexpansive） and weakly semi-closed operators at the origin and their generalizations. The main condition in our results is formulated in terms of axiomatic measures of weak compactness.

关键词： measure of weak noncompactness weakly condensing and weakly nonexpansive weakly sequentially continuous weakly semi-closed at the origin fixedpoint theorem

无界域上1-集弱压缩算子的新不动点结果(英文)

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应用数学 2013年第2期26卷 268-276页

作者：许绍元 afif ben amar 韩山师范学院数学与应用数学系广东潮州521041 Département de Mathématiques Université de GafsaCité Universitaire Zarrouk

本文证明Banach空间中无界域上一类弱序列连续和1-集弱压缩算子的若干新不动点定理.我们引入原点处弱半闭算子,得到该算子的若干不动点定理.进而将著名的Leray-Schauder不动点定理、Altman定理、Roth定理和Petryshyn定理推广到弱序列连... 详细信息

本文证明Banach空间中无界域上一类弱序列连续和1-集弱压缩算子的若干新不动点定理.我们引入原点处弱半闭算子,得到该算子的若干不动点定理.进而将著名的Leray-Schauder不动点定理、Altman定理、Roth定理和Petryshyn定理推广到弱序列连续算子和1-集弱压缩算子以及原点处弱半闭算子的情形.本文的主要结果依赖于非紧性弱原子测度的有关条件.

关键词：非紧性测度弱凝聚和弱非扩张弱序列连续在原点弱半闭不动点定理

Fixed Point Theory for 1-Set Weakly Contractive Operators in Banach Spaces

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Analysis in Theory and Applications 2013年第3期29卷 208-220页

作者： Shaoyuan Xu afif ben amar Department of Mathematics and Statistics Hanshan Normal University De'partement de Mathe'matiques Faculte' des Sciences de SfaxUniversite' de SfaxSfaxTunisia

In this work, using an analogue of Sadovskii＇s fixed point result and several important inequalities we investigate and give new existence theorems for the nonlinear operator equation F（x） =μx, （μ≥1） for some weakly sequentially continuous, weakly condensing and weakly 1-set weakly contractive operators with different boundary conditions. Correspondingly, we can obtain some applicable fixed point theorems of Leray-Schauder, Altman and Furi-Pera types in the weak topology setting which generalize and improve the corresponding results of [3,15,16].

关键词： Weakly condensing weakly sequentially continuous fixed point theorem operator equation.

On Some Fixed Point Theorems for 1-Set Weakly Contractive Multi-Valued Mappings with Weakly Sequentially Closed Graph

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Advances in Pure Mathematics 2011年第4期1卷 163-169页

作者： afif ben amar Aneta Sikorska-Nowak 不详

In this paper we prove Leray-Schauder and Furi-Pera types fixed point theorems for a class of multi-valued mappings with weakly sequentially closed graph. Our results improve and extend previous results for weakly sequentially closed maps and are very important in applications, mainly for the investigating of boundary value problems on noncompact intervals.

关键词： Measures of Weak Noncompactness Weakly Condensing Weakly Nonexpansive

Performance Improved of a Lime and Hemp-Based Concrete through the Addition of Metakaolin

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Fluid Dynamics & Materials Processing 2023年第5期19卷 1091-1113页

作者： Suzanne Daher amar benazzouk Haïkel ben Hamed Thierry Langlet Universitéde Picardie Jules Verne Avenue des Facultés Amiens80025France

This work describes in detail the experimental investigation of the physico-mechanical properties of nonstructural hemp concrete(usually used as insulating wall material)when the Air-lime based Tradial PF70 binder is partially replaced using *** objective is to reduce the amount of free Ca2+ions in the binder as these are responsible for the degradation of vegetables particles and can therefore induce a loss of mechanical *** order to assess the effectiveness of pozzolanic reaction,amounts of 0%,10%,and 20%*** Air-lime binder were replaced by the Metakaolin material,while testing the mechanical properties of concrete specimens containing 200%and 300%of hemp *** SEM and EDX analysis,a tight relationship has been found to exist between the Metakaolin content and physical-mechanical properties of *** pozzolanic reaction consumes calcium hydroxide from binder to produce Hydrated Calcium Silicates(C-S-H)and in turn,this leads to a decrease in the pH-value of the pore solution which is the main factor responsible for hemp particle degradation.

关键词： Agro-sourced materials hemp particles tradical PF70 binder metakaolin pozzolanic products mechanical properties deformability particle mineralisation SEM and EDX analyses

Experimental Testing of Cellular Construction Materials Containing Flax Particles

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Fluid Dynamics & Materials Processing 2023年第3期19卷 723-741页

作者： Hamadou-Ali Mohamed benazzouk amar Haïkel ben Hamed Arash Jamali Laboratoire des Technologies Innovantes(UR-UPJV 3899)-UPJV Amiens80000France Plateforme de Microscopie Electronique-UPJV HUB de l’Energie80039Amiens

The feasibility of a sustainable non-autoclaved cellular concrete,based on flax vegetable co-products,for the production of usable specimen in the lightweight construction field,has been investigated *** produced specimen,containing various volume ratios of flax particles with respect to preformulatd Tradical PF70 lime binder of 0,1,and 2,were lightened by creating a porous structure in the matrix through the addition of 0.3%*** powder(able to react with calcium hydroxide from the binder and result in microscopic air-bubbles).Fresh and hardened specimen properties,including hydration,fresh density,porosity,hardened density,compressive and flexural strengths,toughness energy,and dry thermal conductivity at different temperatures,were assessed for varying flax-to-binder *** have shown that the addition of Aluminum powder leads to restrain the setting time delay of binder-based ***,the hardened material displays a significant decrease in specimen density,thereby resulting in a compressive strength level compatible with that required in the cellular construction materials *** also highlighted the ability of added flax to induce a change in the specimen from brittle to ductile ***,a high degree of thermal insulation can be achieved,which makes the cellular specimen based on flax particle suitable as insulated-bearing walls material.

关键词： Flax particles cellular concrete lightening porous structure physico-mechanical properties thermal conductivity

Cannabis and Psychosis: A Review of the Risk Factors Involved

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American Journal of Plant Sciences 2020年第12期11卷 1949-1990页

作者： Mohamed ben amar Substance Abuse Program Faculty of Continuing Education Université de Montréal Montréal Canada

Abundant literature suggests the hypothesis that cannabis use leads to the onset of psychotic symptoms. However, the nature of the association and the causal link remain controversial. This review aims to identify the risk factors involved in the etiopathogenesis of psychosis or psychotic features. Our electronic search found 1653 studies published until March 1st 2020. Longitudinal studies and literature reviews were selected if they addressed specifically the issues of the cannabis/psychosis relationship and the eventual risk factors involved. Our systematic review identified six potential risk factors involved in the association. They are, in decreasing importance, the dose-response relationship (quantity, frequency and duration of cannabis use), the early age of cannabis consumption, genetic susceptibility, childhood trauma, cigarette smoking and urban environment. In contrast, a significant inverse relationship exists between cannabidiol (CBD) and psychosis: cannabidiol is associated with less psychotic symptoms and manifests antipsychotic properties. Further studies are needed to establish a clear causal relationship between cannabis and psychosis and to identify the qualitative and quantitative contribution of specific risk factors on its onset and sustainability.

关键词： Cannabis Marijuana Hashish Psychosis Schizophrenia Risk Factors

Analytic Beta-Wavelet Transform-Based Digital Image Watermarking for Secure Transmission

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Computers, Materials & Continua 2022年第3期70卷 4657-4673页

作者： Hesham Alhumyani Ibrahim Alrube Sameer Alsharif Ashraf afifi Chokri ben amar Hala S.El-Sayed Osama S.Faragallah Department of Computer Engineering College of Computers and Information TechnologyTaif UniversityP.O.11099Taif21944Saudi Arabia Department of Electrical Engineering Faculty of EngineeringMenoufia UniversityShebin El-Kom32511Egypt Department of Information Technology College of Computers and Information TechnologyTaif UniversityP.O.11099Taif21944Saudi Arabia

The rapid development in the information technology field has introduced digital watermark technologies as a solution to prevent unauthorized copying and redistribution of *** article introduces a self-embedded image verification and integrity *** images are firstly split into dedicated segments of the same block ***,different Analytic Beta-Wavelet(ABW)orthogonal filters are utilized for embedding a self-segment watermark for image segment using a predefined *** orthogonal filter coefficients are estimated to improve image reconstruction under different block *** conduct a comparative study comparing the watermarked images using three kinds of ABW filters for block sizes 64×64,128×128,and 256×*** embed the watermark using the ABW-based image watermarking method in the 2-level middle frequency sub-bands of the ABW digital image *** imperceptibility and robustness of the ABW-based image watermarking method image is evaluated based on the Peak Signal to Noise Ratio(PSNR)and Correlation coefficient *** the implementation results,we came to know that this ABW-based image watermarking method can withstand many image manipulations compared to other existing methods.

关键词： Watermarking ABW median filtering JPEG compression PSNR

Distributed Relay Diversity Systems for OFDM-Based Networks

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International Journal of Communications, Network and System Sciences 2008年第3期1卷 215-227页

作者： afif OSSEIRAN Andrew LOGOTHETIS Slimane ben SLIMANE Airspan Networks previously with Ericsson Research Ericsson Research Stockholm Sweden Royal Institute of Technology (KTH) Stockholm Sweden

In this paper, distributed relay diversity systems are analyzed, modeled and evaluated in an Orthogonal Frequency Division Multiplexing (OFDM) based networks. The investigated distributed relay diversity schemes extend the ideas of a single hop transmit antenna schemes such as Cyclic Delay Diversity (CDD), Space Time Transmit Diversity (STTD), transmit Coherent Combining (CC) and Selection Diversity (SD) to distributed diversity systems. In contrast to the classical single hop system, the antennas in the distributed systems belongs to distributed relays instead of being co-located at the transmitter. The distributed relay diversity methods considered in this paper: Relay CDD (RCDD), Relay Alamouti (***), Relay CC (RCC) and Relay SD (RSD) are compared to the traditional 1-hop system. Analytical expressions for the received Signal to Interference Noise Ratio (SINR) are derived and used in a dynamic multi-cell multi-user simulator. Results show considerable SINR gains for both Round Robin and Max-SINR schedulers. The SINR gains translate into substantial cell throughput gains, up to 200%, compared to 1-hop systems. Despite its low complexity, the RCDD scheme has similar performance to that of other more sophisticated 2-hop schemes such as Relay Alamouti and Relay Coherent Combining. Marginally better results are observed for the Relay Selection Diversity scheme.

关键词： Coherent Combining Cooperative Communication Cyclic Delay Diversity Multi-User Diversity OFDM Relay Node Selection Diversity Space Time Transmit Diversity System Performance