• Article  

      Complex-valued tapers 

      Politis, Dimitris Nicolas (2005)
      The spectral estimation method based on the average of short, tapered periodograms is re-examined. The bias of such estimators is typically O(1/b2), where b is the length of the short blocks. Much of the current researeh ...
    • Article  

      Conformal mapping for the efficient MFS solution of Dirichlet boundary value problems 

      Karageorghis, Andreas; Smyrlis, Yiorgos-Sokratis (2008)
      In this work, we use conformal mapping to transform harmonic Dirichlet problems of Laplace's equation which are defined in simply-connected domains into harmonic Dirichlet problems that are defined in the unit disk. We ...
    • Article  

      Detection of cavities using the method of fundamental solutions 

      Karageorghis, Andreas; Lesnic, D. (2009)
      The determination of the boundary of a cavity, defined here as a perfectly insulated inclusion, within a conducting medium from a single voltage and current flux measurements on the accessible boundary of the medium, can ...
    • Article  

      Harmonic generation with a dual frequency pulse 

      Keravnou, Christina P.; AVERKIOU, MICHALAKIS A. (2013)
      Nonlinear imaging was utilized in commercial ultrasound systems over the last 15 years offering major advantages in many clinical applications. In this work, pulsing schemes (pulse inversion, power modulated pulse inversion ...
    • Article  

      A matrix decomposition MFS algorithm for problems in hollow axisymmetric domains 

      Tsangaris, Th; Smyrlis, Yiorgos-Sokratis; Karageorghis, Andreas (2006)
      In this work we apply the Method of Fundamental Solutions (MFS) with fixed singularities and boundary collocation to certain axisymmetric harmonic and biharmonic problems. By exploiting the block circulant structure of the ...
    • Article  

      The method of fundamental solutions for inhomogeneous elliptic problems 

      Poullikkas, A.; Karageorghis, Andreas; Georgiou, Georgios C. (1998)
      We investigate the use of the Method of Fundamental Solutions (MFS) for solving inhomogeneous harmonic and biharmonic problems. These are transformed to homogeneous problems by subtracting a particular solution of the ...
    • Article  

      Methods of fundamental solutions for harmonic and biharmonic boundary value problems 

      Poullikkas, A.; Karageorghis, Andreas; Georgiou, Georgios C. (1998)
      In this work, the use of the Method of Fundamental Solutions (MFS) for solving elliptic partial differential equations is investigated, and the performance of various least squares routines used for the solution of the ...
    • Article  

      The MFS for the solution of harmonic boundary value problems with non-harmonic boundary conditions 

      Li, M.; Chen, C. S.; Karageorghis, Andreas (2013)
      We investigate applications of the method of fundamental solutions (MFS) for the numerical solution of two-dimensional boundary value problems in complex geometries, governed by the Laplace equation and subject to Dirichlet ...
    • Article  

      Multilevel characterizations of anisotropic function spaces 

      Kyriazis, George C. (2005)
      We present a general method for extending decomposition systems of L 2(ℝd) to decomposition systems for the anisotropic Triebel-Lizorkin and Besov spaces, Fp,qα,s and Bp,qα,s, respectively, for the full range of the indexes. ...
    • Article  

      The singular function boundary integral method for biharmonic problems with crack singularities 

      Elliotis, Miltiades C.; Georgiou, Georgios C.; Xenophontos, Christos A. (2007)
      We use the singular function boundary integral method (SFBIM) to solve two model fracture problems on the plane. In the SFBIM, the solution is approximated by the leading terms of the local asymptotic solution expansion, ...
    • Article  

      Solution of the planar Newtonian stick-slip problem with the singular function boundary integral method 

      Elliotis, Miltiades C.; Georgiou, Georgios C.; Xenophontos, Christos A. (2005)
      A singular function boundary integral method (SFBIM) is proposed for solving biharmonic problems with boundary singularities. The method is applied to the Newtonian stick-slip flow problem. The streamfunction is approximated ...
    • Article  

      Some aspects of the Method of Fundamental Solutions for certain harmonic problems 

      Smyrlis, Yiorgos-Sokratis; Karageorghis, Andreas (2001)
      The Method of Fundamental Solutions (MFS) is a boundary-type method for the solution of certain elliptic boundary value problems. The basic ideas of the MFS were introduced by Kupradze and Alexidze and its modern form was ...
    • Doctoral Thesis  Open Access

      Topics in geometric function theory and harmonic analysis 

      Lamprecht, Martin (Πανεπιστήμιο Κύπρου, Σχολή Θετικών και Εφαρμοσμένων Επιστημών / University of Cyprus, Faculty of Pure and Applied Sciences, 2015-05)
      Στην παρούσα διατριβή μελετώνται διάφορα προβλήματα της Γεωμετρικής Θεωρίας Συναρτήσεων και της Αρμονικής Ανάλυσης. Στο πρώτο κεφάλαιο αποδεικνύεται νέα επέκταση της ανισότητας ημιτόνου του Vietoris. Το ίδιο κεφάλαιο ...
    • Conference Object  

      Vortex shedding lock-on in a periodic freestream flow past a circular cylinder 

      Olinger, D. J.; Alexandrou, Andreas N.; Dutka, J. (Publ by ASME, 1993)
      Vortex lock-on phenomena in flow past a circular cylinder with a periodic component superimposed on the mean free stream flow is investigated using concepts from dynamical systems (chaos) theory. Numerical results show ...