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Isolation Enhancement in a Compact Four-Element MIMO Antenna for Ultra-Wideband Applications

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Computers, Materials & Continua 2023年第4期75卷 911-925页

作者： awais Khan Shahid Bashir Salman Ghafoor Hatem Rmili Jawad Mirza Ammar ahmad Department of Electrical Engineering University of Engineering and TechnologyPeshawar25000Pakistan Department of Electrical Engineering University of Science and TechnologyBannu28100Pakistan School of Electrical Engineering and Computer Science(SEECS) National University of Sciences and Technology(NUST)Islamabad44000Pakistan Electrical and Computer Engineering Department Faculty of EngineeringKing Abdulaziz UniversityJeddahSaudi Arabia K.A.CARE Energy Research and Innovation Center King Abdulaziz UniversityJeddah21589Saudi Arabia SEECS Photonic Research Group National University of Sciences and TechnologyIslamabad44000Pakistan

Mutual coupling reduction or isolation enhancement in antenna arrays is an important area of research as it severely affects the performance of an *** this paper,a new type of compact and highly isolated Multiple-Input-Multiple-Output(MIMO)antenna for ultra-wideband(UWB)applications is *** design consists of four radiators that are orthogonally positioned and confined to a compact 40×40×0.8 mm3 *** final antenna design uses an inverted L shape partial ground to produce an acceptable reflection coefficient(S1120 db for majority of the UWB *** antenna was fabricated and tested with the vector network analyzer(VNA)and in an anechoic chamber for scattering parameters and radiation ***,different MIMO diversity performance metrics are also measured to validate the proposed *** simulation results and the experimental results from the constructed model agree quite *** proposed antenna is compared with similar designs in recently published literature for various performance *** of its low envelope correlation coefficient(ECC9.99 dB),peak gain of 4.6 dB,reduced channel capacity loss(CCL<0.4 b/s/Hz),and average radiation efficiency of over 85%,the proposed MIMO antenna is ideally suited for practical UWB applications.

关键词： Multiple input multiple output antennas envelope correlation coefficient defected ground structure ultra wide band diversity gain

Catalytic evaluation of promoted CeO_2-ZrO_2 by transition, alkali, and alkaline-earth metal oxides for diesel soot oxidation

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Journal of Environmental Sciences 2013年第12期25卷 2498-2506页

作者： ali alinezhadchamazketi Abas ali Khodadadi Yadollah Mortazavi ahmad Nemati Catalysis and Nanostructured Materials Laboratory College of EngineeringSchool of Chemical EngineeringUniversity of Tehran Oil and Gas Processing Center of Excellence College of EngineeringUniversity of Tehran

Series of mixed metal oxides were synthesized by gel-combustion method and their catalytic activities for soot oxidation were investigated. The catalysts were M-Ce-Zr （M = Mn, Cu, Fe, K, Ba, Sr）, and χK-20Mn-Ce-Zr （χ= 0, 5, 10, 20）, they were characterized by XRD, SEM, TPR and BET surface area techniques. The results of soot temperature programmed oxidation （TPO） in an O2 oxidizing atmosphere indicate that K-Ce-Zr has the highest catalytic activity for soot oxidation under loose contact condition, due to enhancement of the soot and catalyst contacts. On the other hand, under a tight contact condition, Mn-Ce-Zr and Cu-Ce-Zr nano-composites have high activities for soot oxidation and lower the soot TPO peak temperatures by about 280 and 270℃, respectively, as compared to non-catalytic soot oxidation. Furthermore, the addition of up to 10 wt.% potassium oxides into Mn-Ce-Zr increases its catalytic activity and further reduces the soot TPO peak temperature by about 40℃ under loose contact condition.

关键词： soot oxidation diesel ceria-zirconia metal oxide

Clustering in the presence of side information: a non-linear approach

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International Journal of Intelligent Computing and Cybernetics 2019年第2期12卷 292-314页

作者： ahmad ali Abin Faculty of Computer Science and Engineering Shahid Beheshti UniversityTehranIran

Purpose–Constrained clustering is an important recent development in clustering *** goal of an algorithm in constrained clustering research is to improve the quality of clustering by making use of background *** purpose of this paper is to suggest a new perspective for constrained clustering,by finding an effective transformation of data into target space on the reference of background knowledge given in the form of pairwise must-and cannot-link ***/methodology/approach–Most of existing methods in constrained clustering are limited to learn a distance metric or kernel matrix from the background knowledge while looking for transformation of data in target *** previous efforts,the author presents a non-linear method for constraint clustering,whose basic idea is to use different non-linear functions for each dimension in target ***–The outcome of the paper is a novel non-linear method for constrained clustering which uses different non-linearfunctions for each dimension in target *** proposed method for a particular case is formulated and explained for quadratic *** reduce the number of optimization parameters,the proposed method is modified to relax the quadratic function and approximate it by a factorized version that is easier to *** results on synthetic and real-world data demonstrate the efficacy of the proposed ***/value–This study proposes a new direction to the problem of constrained clustering by learning a non-linear transformation of data into target space without using kernel *** work will assist researchers to start development of new methods based on the proposed framework which will potentially provide them with new research topics.

关键词： Cannot-link Constrained clustering Instance-level constraints Must-link Quadratic functions,Side information

EBAKE-SE: A novel ECC-based authenticated key exchange between industrial IoT devices using secure element

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Digital Communications and Networks 2023年第2期9卷 358-366页

作者： Chintan Patel ali Kashif Bashir ahmad ali AlZubi Rutvij Jhaveri School of Artificial Intelligence Information Technology and Cyber SecurityRashtriya Raksha UniversityGujaratIndia Department of Computing and Mathematics Manchester Metropolitan UniversityUnited Kingdom Woxsen School of Business Woxsen UniversityIndia Department of Computer Science and Mathematics Lebanese American UniversityBeirutLebanon Computer Science Department Community CollegeKing Saud UniversityP.O.Box 28095Riyadh11437Saudi Arabia Department of Computer Science and Engineering School of TechnologyPandit Deendayal Energy UniversityGujaratIndia

Industrial IoT(IIoT)aims to enhance services provided by various industries,such as manufacturing and product *** suffers from various challenges,and security is one of the key challenge among those *** and access control are two notable challenges for any IIoT based industrial *** IoT based Industry 4.0 enterprise designs networks between hundreds of tiny devices such as sensors,actuators,fog devices and ***,articulating a secure authentication protocol between sensing devices or a sensing device and user devices is an essential step in IoT *** this paper,first,we present cryptanalysis for the certificate-based scheme proposed for a similar environment by Das et *** prove that their scheme is vulnerable to various traditional attacks such as device anonymity,MITM,and *** then put forward an interdevice authentication scheme using an ECC(Elliptic Curve Cryptography)that is highly secure and lightweight compared to other existing schemes for a similar ***,we set forth a formal security analysis using the random oracle-based ROR model and informal security analysis over the Doleve-Yao *** this paper,we present comparison of the proposed scheme with existing schemes based on communication cost,computation cost and security index to prove that the proposed EBAKE-SE is highly efficient,reliable,and trustworthy compared to other existing schemes for an inter-device *** long last,we present an implementation for the proposed EBAKE-SE using MQTT protocol.

关键词： Internet of things Authentication Elliptic curve cryptography Secure key exchange Message Queuing telemetry transport

An Efficient Solid Acid Promoted Synthesis of Quinoxaline Derivatives at Room Temperature

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Chinese Journal of Chemistry 2007年第6期25卷 818-821页

作者： ahmad, Shaabani ali, Maleki Department of Chemistry Shahid Beheshti University PO Box 19396-4716 Tehran Iran

Quinoxaline derivatives have been synthesized in a very short time with excellent yields by the condensation of 1,2-diamines with aliphatic or aromatic 1,2-dicarbonyl compounds or benzilmonoxime in the presence of silica sulfuric acid as a very inexpensive solid acid catalyst at room temperature. The recovery and reuse of the catalyst are also satisfactory.

关键词： silica sulfuric acid quinoxaline 1,2-diketone 1,2-diamine benzilmonoxime

Distinguishing and Correlating Multiple Phases of Metamorphism across Multiply Deformed Regions Using the Axes of Inclusion Trails in Porphyroblasts

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Acta Geologica Sinica(English Edition) 2011年第4期85卷 784-791页

作者： ahmad Afroz SHAH Asghar ali School of Earth and Environmental Sciences James Cook UniversityTownsvilleQld 4811Australia

Successions of FIAs（foliation inflection/intersection axes preserved within porphyroblasts） provide a relative time scale for deformation and ***-situ dating of monazite grains preserved as inclusions within garnet and staurolite porphyroblasts within the foliations defining each FIA from such successions provides a rigorous approach to grouping ages that formed over extended periods of deformation and *** age and FIA progressions confirms the suitability of this approach plus provides access to lengthy histories that cannot otherwise be *** in the Big Thompson region of the Colorado Rocky Mountains,USA began about a SW-NE trending axis defined by FIA set 1 at around 1761±13 *** periods of tectonism occurred around 1712±25 and 1672±21 Ma about W-E and NW-SE trending FIAs 2 and 3, *** in the Balcooma Metamorphic Group NW of Greenvale in NE Queensland, Australia began around 470 Ma with the growth of garnet porphyroblasts about a W-E trending axis defined by FIA set *** monazite grains were preserved as inclusions in this mineral phase but they were in subsequently grown *** then occurred around 443.2±3.8,424±4 and 408.9±8.9 Ma about NNW-SSE,SSW-NNE and W-E trending FIAs 2,3 and 4,*** test of a FIA based approach to monazite dating in tectonic regimes in different parts of the world and with dramatically different ages suggests it can be used in all orogens containing porphyroblasts preserving inclusion trails.

关键词： FIAs porphyroblast monazite Colorado Balcooma Metamorphic Group

Control of Group Velocity via Spontaneous Generated Coherence and Kerr Nonlinearity

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Communications in Theoretical Physics 2014年第9期61卷 410-416页

作者： Hazrat ali Iftikhar ahmad Ziauddin Department of Physics University of Malakand Khyber Pakhtunkhwa Pakistan Department of Physics COMSATS Institute of Information Technology Islamabad Pakistan Institute of Photonics Technologies National Tsing Hua University

A four-level N-type atomic medium is considered to study the effect of spontaneous generated coherence(SGC) and Kerr nonlinearity on light pulse propagation. A light pulse is propagating inside the medium where each atom follows four-level N-type atom-field configuration of rubidium(85Rb) atom. The atom-field interaction leads to electromagnetically induced transparency(EIT) process. The atom-field interaction is accompanied by normal dispersion and in the presence of SGC and Kerr nonlinearity the dispersion property of the proposed atomic medium is modified,which leads to enhancement of positive group index of the medium. The enhancement of positive group index then leads to slow group velocity inside the medium. A more slow group velocity is also investigated by incorporated the collective effect of SGC and Kerr nonlinearity. The control of group velocity inside a four-level N-type atomic medium via collective effect of SGC and Kerr nonlinearity is the major part of this work.

关键词： Kerr nonlinearity spontaneous generated coherence and group index

Enhancing ChatGPT’s Querying Capability with Voice-Based Interaction and CNN-Based Impair Vision Detection Model

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Computers, Materials & Continua 2024年第3期78卷 3129-3150页

作者： awais ahmad Sohail Jabbar Sheeraz Akram Anand Paul Umar Raza Nuha Mohammed Alshuqayran College of Computer and Information Sciences Imam Mohammad Ibn Saud Islamic University(IMSIU)Riyadh11432Saudia Arabia 2 School of Computer Science and EngineeringKyungpook National UniversityDaegu41566South Korea 3 Department of EngineeringManchester Metropolitan UniversityManchesterM156BHUK

This paper presents an innovative approach to enhance the querying capability of ChatGPT,a conversational artificial intelligence model,by incorporating voice-based interaction and a convolutional neural network(CNN)-based impaired vision detection *** proposed system aims to improve user experience and accessibility by allowing users to interact with ChatGPT using voice ***,a CNN-based model is employed to detect impairments in user vision,enabling the system to adapt its responses and provide appropriate *** research tackles head-on the challenges of user experience and inclusivity in artificial intelligence(AI).It underscores our commitment to overcoming these obstacles,making ChatGPT more accessible and valuable for a broader *** integration of voice-based interaction and impaired vision detection represents a novel approach to conversational ***,this innovation transcends novelty;it carries the potential to profoundly impact the lives of users,particularly those with visual *** modular approach to system design ensures adaptability and scalability,critical for the practical implementation of these ***,the solution places the user at its *** responses for those with visual impairments demonstrates AI’s potential to not only understand but also accommodate individual needs and preferences.

关键词： Accessibility in conversational AI CNN-based impair vision detection ChatGPT voice-based interaction recommender system

Newtonian heating in stagnation point flow of Burgers fluid

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Applied Mathematics and Mechanics(English Edition) 2015年第1期36卷 61-68页

作者： T.HAYAT S.ali M.awais M.S.ALHUTHali Department of Mathematics Quaid-i-Azam University Nonlinear Analysis and Applied Mathematics (NAAM) Research Group Faculty of Science King Abdulaziz University Faculty of Engineering Sciences Ghulam Ishaq Khan Institute of Engineering Sciences and Technology Department of Mathematics COMSATS Institute of Information Technology

The Newtonian heating effects in the stagnation point flow of a Burgers fluid are addressed in this paper. The boundary layer flow problems are stated in the spatial domain from zero to infinity. The solution expressions for the velocity and the temperature are obtained and examined for the influential variables. The tabulated values show comparison with the previous results. It is observed that the obtained results are in good agreement with the existing results in limiting sense.

关键词： Burgers fluid Newtonian heating series solutions