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

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

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Current Therapeutics in Primary Sclerosing Cholangitis

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Journal of Clinical and Translational Hepatology 2023年第5期11卷 1267-1281页

作者： Natassia Tan John Lubel William Kemp Stuart Roberts ammar Majeed Department of Gastroenterology and Hepatology Alfred HealthCentral Clinical SchoolMonash UniversityMelbourneAustralia

Primary sclerosing cholangitis(PSC)is an orphan,cholestatic liver disease that is characterized by inflammatory biliary strictures with variable progression to end-stage liver *** pathophysiology is poorly *** biliary inflammation is likely driven by immune dysregulation,gut dysbiosis,and environmental exposures resulting in gutliver crosstalk and bile acid metabolism *** is no proven medical therapy that alters disease progression in PSC,with the commonly prescribed ursodeoxycholic acid being shown to improve liver biochemistry at low-moderate doses(15–23 mg/kg/day)but not alter transplant-free survival or liver-related *** transplantation is the only option for patients who develop end-stage liver disease or refractory complications of *** and antifibrotic agents have not proven to be effective,but there is promise for manipulation of the gut microbiome with fecal microbiota transplantation and *** acid manipulation via alternate synthetic bile acids such as norursodeoxycholic acid,or interaction at a transcriptional level via nuclear receptor agonists and fibrates have shown potential in phase II trials in PSC with several leading to larger phase III *** view of the enhanced malignancy risk,statins,and aspirin show potential for reducing the risk of colorectal cancer and cholangiocarcinoma in PSC *** patients who develop clinically relevant strictures with cholestatic symptoms and worsening liver function,balloon dilatation is safer compared with biliary stent insertion with equivalent clinical efficacy.

关键词： Primary sclerosing cholangitis Bile acid Microbiome 24-Norursodeoxycholic acid Farnesoid X receptor agonists Liver transplant

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An Intelligent Graph Edit Distance-Based Approach for Finding Business Process Similarities

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Computers, Materials & Continua 2021年第12期69卷 3603-3618页

作者： Abid Sohail ammar Haseeb Mobashar Rehman Dhanapal Durai Dominic Muhammad Arif Butt Department of Computer Science COMSATS University IslamabadLahorePakistan Faculty of Information and Communication Technology Universiti Tunku Abdul RahmanKamparPerakMalaysia Universiti Teknologi PETRONAS Bandar Seri IskandarTronoh PerakMalaysia Punjab University College of Information Technology University of the PunjabLahorePakistan

There are numerous application areas of computing similarity between process *** includes finding similar models from a repository,controlling redundancy of process models,and finding corresponding activities between a pair of process *** similarity between two process models is computed based on their similarity between labels,structures,and execution *** attempts have been made to develop similarity techniques between activity labels,as well as their execution ***,a notable problem with the process model similarity is that two process models can also be similar if there is a structural variation between ***,neither a benchmark dataset exists for the structural similarity between process models nor there exist an effective technique to compute structural *** that end,we have developed a large collection of process models in which structural changes are handcrafted while preserving the semantics of the ***,we have used a machine learning-based approach to compute the similarity between a pair of process models having structural and label ***,we have evaluated the proposed approach using our generated collection of process models.

关键词： Machine learning intelligent data management similarities of process models structural metrics dataset graph edit distance process matching artificial intelligence

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A Novel Improved Artificial Bee Colony and Blockchain-Based Secure Clustering Routing Scheme for FANET

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China Communications 2021年第7期18卷 103-116页

作者： Liang Zhao Muhammad Bin Saif ammar Hawbani Geyong Min Su Peng Na Lin Shenyang Aerospace University ShenyangLiaoning 110136China University of Science and Technology of China HefeiChina University of Exeter ExeterUK

Flying Ad hoc Network(FANET)has drawn significant consideration due to its rapid advancements and extensive use in civil ***,the characteristics of FANET including high mobility,limited resources,and distributed nature,have posed a new challenge to develop a secure and ef-ficient routing scheme for *** overcome these challenges,this paper proposes a novel cluster based secure routing scheme,which aims to solve the routing and data security problem of *** this scheme,the optimal cluster head selection is based on residual energy,online time,reputation,blockchain transactions,mobility,and connectivity by using Improved Artificial Bee Colony Optimization(IABC).The proposed IABC utilizes two different search equations for employee bee and onlooker bee to enhance convergence rate and exploitation ***,a lightweight blockchain consensus algorithm,AI-Proof of Witness Consensus Algorithm(AI-PoWCA)is proposed,which utilizes the optimal cluster head for *** AI-PoWCA,the concept of the witness for block verification is also involved to make the proposed scheme resource efficient and highly resilient against 51%*** results demonstrate that the proposed scheme outperforms its counterparts and achieves up to 90%packet delivery ratio,lowest end-to-end delay,highest throughput,resilience against security attacks,and superior in block processing time.

关键词： improved artificial bee colony optimization optimal cluster head selection secure routing blockchain lightweight consensus protocol

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Combining Monte Carlo simulations and dosimetry measurements for process control in the Tunisian Cobalt-60 irradiator after three half lives of the source

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Nuclear Science and Techniques 2017年第9期28卷 119-128页

作者： Leila Ounalli Maroua Bhar Arbi Mejri Kais Manai ammar Bouabidi Shayma Mohamed Abdallah Nafaa Reguigui Tunisian Center for Nuclear Sciences and Technology Technopark Sidi Thabet 2020 Ariana Tunisia Laboratory on Energy and Matter for Nuclear SciencesDevelopment Technopark Sidi Thabet 2020 Ariana Tunisia Tunisian Higher Institute of Medical Technologies 9 RueZouhair Essafi 1006 TUNIS 1006 Tunis Tunisia Faculty of Sciences of Tunis Technopark Sidi Thabet2020 Ariana Tunisia College of Science and Arts University of Bisha BishaKingdom of Saudi Arabia

To check the dose uniformity and to determine the efficiency of medical devices sterilization by gamma irradiation after three half lives of the source, calculations of the absorbed dose were carried out. Monte Carlo simulations and dosimetry measurements, were established to study the radiation processing quality control. An isodose chart was created by GEANT4 Monte Carlo code to evaluate the absorbed dose rate uniformity inside the irradiation room from the year of the installation until the year of the source reload. The dose uniformity ratio(DUR) is deduced from maximum and minimum experimental doses in medical devices after three half lives of the source.

关键词：剂量测量蒙特卡洛半衰期过程控制辐照模拟钴-60 突尼斯 Geant4

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Solution of KdV and mKdV Equationsusing Darboux Transformation

Solution of KdV and mKdV Equationsusing Darboux Transformati...

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作者： Wael Sulayman Miftah ammar 浙江科技学院

学位级别：硕士

Internal solitary waves(ISWs)are common in the ocean and perform vital functions in a variety of ways,including mass and nutrient movement via *** history of an initial solitary wave solved by a completely nonlinear model,modified model,and Darboux transformation model is observed and compared to the evolution for the weakly nonlinear wave equations,the KDV *** waves or solitons as solutions to the Korteweg-de Vries equation(Kd V)and the mordified-Korteweg-de Vries equation(m Kd V)which are non-linear partial differential equations(PDE)of third order have been of interest already since 150 *** this thesis some of the methods used in solving this equations were observed and collected,the derivation of the equations were observed and the Darboux transformation of the equations was also *** applications of the equation in engineering simulation was investigated by employing the Homotopy perturbation transform method(HPTM)for solving the generic model of nonlinear fifth order Kd V equations for the study of magneto-acoustic waves in plasma.

关键词： shallow water waves Solutions KDV equations Solutions m KDV equations Darboux Transformations HPTM

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Lattice Boltzmann Modeling of Miscible Multicomponent Gas Mixtures in the Rarefied Regime

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Communications in Computational Physics 2022年第9期32卷 1179-1216页

作者： Michel Ho Sami ammar Sebastien Leclaire Marcelo Reggio Jean-Yves Trepanier Departement of Mechanical Engineering Polytechnique Montreal2500 Chemin de PolytechniqueMontreal H3T 1J4Canada

An extension to rarefied flow regimes of the lattice Boltzmann methodbased model for miscible mixtures developed by Vienne et al.(Physical Review E 100.2(2019):023309)is *** model is applied to study the gas phase separation phenomenon in mixture flows that traditional macroscopic approaches fail to *** extension includes a wall function approach with an empirical coefficient to define an effectivemean free path in solid geometries,which locally defines the kinematic viscosity and binary diffusion *** algorithm is also modified by a local multi-relaxation time collision operator and slip boundary conditions at solid *** mixture flow simulations are conducted through a 2D plane microchannel within the slip and early transition flow *** a miscible gaseous phase,the mixture loses its homogeneity and independent velocity profiles for each component are observed in the rarefied regime and captured with the current *** addition,the gas separation phenomenon increases with the rarefaction rate and the molecular mass *** individual treatment of the species within mixture flows in the developed lattice Boltzmann model helps understanding the increasing independent behavior of the individual specieswithin themixture as the regime becomesmore rarefied.

关键词： Lattice Boltzmann gaseous mixtures rarefied regimes

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Characterizations of friction welding joint interface for AISI316

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China Welding 2019年第1期28卷 42-48页

作者： ammar Jabbar Hassan Taoufik Boukharouba Djamel Miroud Mechanical Engineering Departement Houari Boumediene Universtity of Sciences and Technology

Because of heat amount is different from peripheral to central of friction welding interface, which is leaded to vary the characterizations along that interface. Current study, respectively, focused on the effect of different friction pressure on micro-structural and mechanical properties of that friction welding joint interface. Presently, these friction pressures are 110, 130, 150 and 170 MPa while kept all other conditions constant. The effects of different friction pressure on welding interface characterization were investigated by EDX, SEM, tensile, compression, impact and hardness tests. The tensile tests carried out on the standardized test piece with diameter 6 mm and 8 mm, thus, compression tests were extracted from the positions of 0°, 45°& 90° with test specimen of 4 mm diameter and 6.5 mm length at weld center. Whereas, the impact test pieces were picked up in two positions, the first one is symmetrical, which it obtained to the respect of the rotation axis and the interface, on the other hand, the second one is non-symmetrical with the axis of rotation and symmetrical to the interface, for making the notch head coincide with the center of the welded joint, The obtained results showed that with reducing of friction pressure will present lack of bonding increasing from peripheral toward the welding center, which will responsible on reducing of the mechanical properties such as tensile, compression and impact strength.

关键词： friction pressure tensile strength compression strength hardness impact strength

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Complications and its risk factors of percutaneous subclavian vein catheters in pediatric patients:enhancing the outcomes of a university hospital in a low-income and middle-income country

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World Journal of Pediatric Surgery 2023年第1期6卷 36-41页

作者： Anouar Jarraya Manel Kammoun Ameni Chtourou Saloua ammar Kamel Kolsi The Anesthesiology department University of Sfax Faculty of Medicine of SfaxSfaxTunisia Department of Pediatric Surgery Hedi Chaker HospitalSfaxTunisia University of Sfax Faculty of Medicine of Sfax SfaxTunisia

Objective Assessing central venous catheter-related complications with regular feedback and investigating risk factors are mandatory to enhance *** aim of this study is to assess our experience in the management of pediatric subclavian vein catheters(SVCs)and to investigate the main risk factors for *** In this prospective observational study,we included children aged 3 months to 14 years who underwent infraclavicular subclavian vein catheterization consecutively using the anatomic landmark *** were divided into two groups:group 1 included complicated catheters and group 2 included noncomplicated *** management protocol was standardized for all *** comparing the two groups,univariate and multivariate logistic regression were used to investigate the risk factors for *** In this study,we included 134 pediatric *** rate of complications was 32.8%.The main complications were central line-associated bloodstream infection(63.6%),bleeding and/or hematoma(22.7%),mechanical complications(13.6%),and vein thrombosis(13.6%).After adjustment for confounding factors,predictors of catheter-related complications were difficult insertion procedure(adjusted odds ratio(aOR)=9.4;95%confidential interval(CI):2.32 to 38.4),thrombocytopenia(aOR=4.43;95%CI:1.16 to 16.86),comorbidities(aOR=2.93;95%CI:0.58 to 14.7),and neutropenia(aOR=5.45;95%CI:2.29 to 13.0).Conclusions High rates of complications were associated with difficult catheter placement and patients with comorbidities and severe *** reduce catheter-related morbidity,we suggest an ultrasoundguided approach,a multidisciplinary teaching program to improve nursing skills,and the use of less invasive devices for patients with cancer.

关键词： patients catheter pediatric

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Modelling the combined effect of surface roughness and topography on bacterial attachment

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Journal of Materials Science & Technology 2021年第22期81卷 151-161页

作者： Subash Bommu Chinnaraj Pahala Gedara Jayathilake Jack Dawson Yasmine ammar Jose Portoles Nicholas Jakubovics Jinju Chen School of Engineering Newcastle UniversityNewcastle Upon TyneUK Department of Oncology University of OxfordUK School of Dental Sciences Newcastle UniversityNewcastle Upon TyneUK

Bacterial attachment is a complex process affected by flow conditions,imparted stresses,and the surface properties and structure of both the supporting material and the *** on the initial attachment of cells of the bacterium Streptococcus gordonii(***),an important early coloniser of dental plaque,to samples of stainless steel(SS)have been reported in this *** primary aim motivating this study was to establish what affect,if any,the surface roughness and topology of samples of SS would have on the initial attachment of cells of the bacterium *** material and bacterium were chosen by virtue of their relevance to dental implants and dental implant *** to bacterial attachment,surfaces become conditioned by the interfacing environment(salivary pellicle from the oral cavity for instance).For this reason,cell attachment to samples of SS pre-coated with saliva was also *** implementing the Extended Derjaguin Landau Verwey and Overbeek(XDLVO)theory coupled with convection-diffusion-reaction equations and the surface roughness information,a computational model was developed to help better understand the physics of cell *** roughness was modelled by reconstructing the surface topography using statistical parameters derived from atomic force microscopy(AFM)*** this computational model,the effects of roughness and surface patterns on bacterial attachment were examined quantitatively in both static and flowing fluid *** results have shown that rougher surfaces(within the sub-microscale)generally increase bacterial attachment in static fluid conditions which quantitatively agrees with experimental *** flow conditions,computational fluid dynamics(CFD)simulations predicted reduced convection-diffusion inside the channel which would act to decrease bacterial *** combined with surface roughness effects,the computational model also predicted that the surface top

关键词： Bacterial attachment XDLVO theory Computational modelling Surface topography Surface roughness

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