Browsing Mathematics, Statistics & Physics by Title

Now showing items 564-583 of 666

    • Rough oscillatory singular integrals on ℝⁿ 

      Al-Qassem, Hussain Mohammad; Cheng, Leslie; Pan, Yibiao ( Instytut Matematyczny , 2014 , Article)
      We establish sharp bounds for oscillatory singular integrals with an arbitrary real polynomial phase P. The kernels are allowed to be rough both on the unit sphere and in the radial direction. We show that the bounds grow ...

    • Run Rules-Based EWMA Charts for Efficient Monitoring of Profile Parameters 

      Yeganeh, Ali; Shadman, Ali Reza; Triantafyllou, Ioannis S.; Shongwe, Sandile Charles; Abbasi, Saddam Akber ( Institute of Electrical and Electronics Engineers Inc. , 2021 , Article)
      In usual quality control methods, the quality of a process or product is evaluated by monitoring one or more quality characteristics using their corresponding distributions. However, when the quality characteristic is ...

    • Sampling of Multiple Variables Based on Partially Ordered Set Theory 

      Panahbehagh, Bardia; Bruggemann, Rainer; Salehi, Mohammad ( Iranian Statistical Society , 2021 , Article)
      We introduce a new method for ranked set sampling with multiple criteria. The method relaxes the restriction of selecting just one individual variable from each ranked set. Under the new method for ranking, units are ranked ...

    • SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy 

      Laith J., Abu-Raddad; Chemaitelly, Hiam; Coyle, Peter; Malek, Joel A.; Ahmed, Ayeda A.; ... more authors ( Elsevier , 2021 , Article)
      Background Reinfection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented, raising public health concerns. SARS-CoV-2 reinfections were assessed in a cohort of antibody-positive persons ...

    • SARS-CoV-2 infection hospitalization, severity, criticality, and fatality rates in Qatar 

      Seedat, Shaheen; Chemaitelly, Hiam; Ayoub, Houssein H.; Makhoul, Monia; Mumtaz, Ghina R.; ... more authors ( Nature Research , 2021 , Article)
      The SARS-CoV-2 pandemic resulted in considerable morbidity and mortality as well as severe economic and societal disruptions. Despite scientific progress, true infection severity, factoring both diagnosed and undiagnosed ...

    • SEIRD model for Qatar COVID-19 outbreak: A case study 

      Ghanam, Ryad; Boone, Edward L.; Abdel-Salam, Abdel Salam G. ( Intercollegiate Biomathematics Alliance , 2021 , Article)
      The COVID-19 outbreak of 2020 has required many governments to develop mathematical-statistical models of the outbreak for policy and planning purposes. This work provides a tutorial on building a compartmental model using ...

    • Selective gas sensors using graphene and CuO nanorods 

      Ayesh A.I.; Ahmed R.E.; Al-Rashid M.A.; Alarrouqi R.A.; Saleh B.; ... more authors ( Elsevier B.V. , 2018 , Article)
      This work reports on the fabrication of sensitive and selective gas sensors fabricated using graphene and/or copper oxide (CuO) nanorods. Herein, three batches of sensors were produced based on graphene/SiO2/Si, CuO nanorods, ...

    • Selective H2S sensor based on CuO nanoparticles embedded in organic membranes 

      Ayesh, Ahmad I.; Abu-Hani, Ayah F. S.; Mahmoud, Saleh T.; Haik, Yousef ( Elsevier B.V. , 2016 , Article)
      We report on H2S gas sensors based on CuO nanoparticles that are embedded within polymer membranes of poly-vinyl-alcohol (PVA) and glycerol ionic liquid (IL). The nanoparticles were fabricated by the colloid microwave ...

    • Selective hydrogen gas sensor using CuFe 2 O 4 nanoparticle based thin film 

      Haija, Mohammad Abu; Ayesh, Ahmad I.; Ahmed, Sadiqa; Katsiotis, Marios S. ( Elsevier B.V. , 2016 , Article)
      Hydrogen gas sensors based on CuFe2O4 nanoparticle thin films are presented in this work. Each gas sensor was prepared by depositing CuFe2O4 thin film on a glass substrate by dc sputtering inside a high vacuum chamber. ...

    • Self-implantation of Cz-Si: Clustering and annealing of defects 

      Abdulmalik, D. A.; Coleman, P. G.; Al-Qaradawi, I. Y. ( Elsevier , 2006 , Article)
      Observations of vacancy clusters formed in Czochralski (Cz) Si after high energy ion implantation are reported. Vacancy clusters were created by 2 MeV Si ion implantation of 1 × 10 15 ions/cm 2 and after annealing between ...

    • Semiparametric MEWMA for Phase II profile monitoring 

      Nassar, Sara H.; Abdel-Salam, Abdel-Salam G. ( John Wiley and Sons Ltd , 2021 , Article)
      A control chart is one of the statistical process techniques that is used to monitor different processes. Some processes are characterized by functions or profiles, and a profile is a functional relationship between the ...

    • Shrinkage estimates of covariance matrices to improve the performance of multivariate cumulative sum control charts 

      Adegoke N.A.; Smith A.N.H.; Anderson M.J.; Abbasi S.A.; Pawley M.D.M. ( Elsevier Ltd , 2018 , Article)
      Multivariate cumulative sum control charts require knowledge of the in-control process covariance parameters. Here, we show that the performance of the multivariate cumulative sum control charts for individual-observation ...

    • A Simple Conservative Chaotic Oscillator with Line of Equilibria: Bifurcation Plot, Basin Analysis, and Multistability 

      Veeman, Dhinakaran; Natiq, Hayder; Ali, Ahmed M.Ali; Rajagopal, Karthikeyan; Hussain, Iqtadar ( Hindawi , 2022 , Article)
      Here, a novel conservative chaotic oscillator is presented. Various dynamics of the oscillator are examined. Studying the dynamical properties of the oscillator reveals its unique behaviors. The oscillator is multistable ...

    • A simple method for finding empirical likelihood type intervals for the ROC curve 

      Baklizi, Ayman ( Wayne State University , 2007 , Article)
      Interval estimation of the ROC curve is considered using the empirical likelihood techniques. Suggested is a procedure that is very simple computationally and avoids the constrained optimization problems usually faced with ...

    • A simple one-dimensional map-based model of spiking neurons with wide ranges of firing rates and complexities 

      Alireza, Bahramian; Ramadoss, Janarthanan; Nazarimehr, Fahimeh; Rajagopal, Karthikeyan; Jafari, Sajad; ... more authors ( Elsevier , 2022 , Article)
      This paper introduces a simple 1-dimensional map-based model of spiking neurons. During the past decades, dynamical models of neurons have been used to investigate the biology of human nervous systems. The models simulate ...

    • Simpler is also better in approximating fixed points 

      Abbas, M.; Khan, Safeer Hussain; Rhoades, B.E. ( Elsevier , 2008 , Article)
      In this paper we demonstrate that a number of fixed point iteration problems can be solved using a modified Krasnoselskij iteration process, which is much simpler to use than the other iteration schemes that have been defined

    • A simulated annealing technique for multi-objective simulation optimization 

      Alrefaei, Mahmoud H.; Diabat, Ali H. ( Elsevier , 2009 , Article)
      In this paper, we present a simulated annealing algorithm for solving multi-objective simulation optimization problems. The algorithm is based on the idea of simulated annealing with constant temperature, and uses a rule ...

    • Simulating local fields in carbon nanotube-reinforced composites for infinite strip with voids 

      Nasser, Mohamed M. S.; Kalmoun, El Mostafa; Mityushev, Vladimir; Rylko, Natalia ( Springer , 2022 , Article)
      A numerical simulation of the thermal properties is conducted for an isotropic and homogeneous infinite strip composite reinforced by carbon nanotubes (CNTs) and containing voids. The CNTs can be uniformly or randomly ...

    • Simulation of natural convective heat transfer and entropy generation of nanoparticles around two spheres in horizontal arrangement 

      Basma, Souayeh; Hammami, Fayçal; Hdhiri, Najib; Alam, Mir Waqas; Yasin, Essam; ... more authors ( Elsevier , 2021 , Article)
      Herein, laminar convective heat transfer from two horizontally arranged spheres has been evaluated by using numerical models inside water-based fluids incorporated with alumina (Al2O3), copper oxide (CuO), and copper (Cu) ...

    • Simultaneous solutions for first order and second order slips on micropolar fluid flow across a convective surface in the presence of Lorentz force and variable heat source/sink 

      Kumar K.A.; Sugunamma V.; Sandeep N.; Mustafa M.T. ( Nature Publishing Group , 2019 , Article)
      This report presents the flow and heat transfer characteristics of MHD micropolar fluid due to the stretching of a surface with second order velocity slip. The influence of nonlinear radiation and irregular heat source/sink ...