• ENDM Proceedings for TREPAM'17: Preface

      Bagdasar, Ovidiu; Popa, Ioan-Lucian; University of Derby; University of Alba Iulia (Elsevier, 2018-06-14)
    • On the geometry of certain periodic non-homogeneous Horadam sequences.

      Bagdasar, Ovidiu; Popa, Ioan-Lucian; University of Derby; University of Alba Iulia (Elsevier, 2016-12)
      Horadam sequences are second-order recurrences depending on a family of four complex parameters: two initial conditions and two recurrence coefficients. The periodicity conditions, as well as the number and geometric structure of self-repeating Horadam sequences of fixed length have been recently investigated. In this paper various geometric properties of non-homogeneous Horadam sequences are explored, including periodicity conditions and the structure of certain periodic orbits.
    • On the ratios and geometric boundaries of complex Horadam sequences.

      Bagdasar, Ovidiu; Hedderwick, Eve; Popa, Ioan-Lucian; University of Derby; University of Alba Iulia (Elsevier, 2018-06-14)
      Horadam sequences are second-order linear recurrences in the complex plane which depend on two initial conditions and two recurrence coefficients which are complex numbers. Recently, numerous papers have been devoted to the periodicity of these sequences, as well as to generalizations and applications. In this paper we investigate aspects related to the sequence of rations of consecutive terms and geometric bounds of Horadam sequences. We also propose some directions for further study.
    • Qualitative case study methodology: Automatic design and correction of ceramic colors.

      Bagdasar, Ovidiu; Birlutiu, Adriana; Chen, Minsi; Popa, Ioan-Lucian; University of Derby; University of Alba Iulia; University of Huddersfield (IEEE, 2017-11)
      This paper is focused on two major problems within the ceramics industry. The reproduction of a desired color from pigments (which is time-intensive), and the correction of colors on the production line (which is costly) are processes which still rely heavily on numerous experiments carried out by human operators. This study presents the key aspects of these two processes and suggests some mathematical and computer sciences tools, aimed at automatizing the current procedures. Data was provided by an industrial partner, where the proposed models and solutions will be tested and validated.