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 General Seminars of 
 Department of Mathematics 
 General Seminars of 
 Department of Mathematics 


Announcements

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This site is to announce General Seminars of our department in this academic year. Below is a list of speakers in reverse chronological order. Our seminars are open to anyone interested to listen and/or give a talk. If you need any assistance, please get in touch with the organizer.


  • STUDENT SEMINARS:
    • Date: May 27, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Place: C301
    • Time: 15:30-16:30
    • Speaker: Ceren Devrimci
    • Title: Generating Copulas
    • Abstract:
      I will present a special case of copulae, namely Archimedean Copulae, their construction, higher-dimensional copulae generations and conditional copulae with application in Archimedean copulae.
    • Speaker: Femin Yalçın
    • Title: Startup Demonstration Test
    • Abstract:
      I will give the definition of Start-up Demonstration Tests and the four types of the Start-up Demonstration Tests. I will give some characteristics of i.i.d. TSTF test. I will introduce Markov dependent CSTF test.
  • May 25, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Mahdi Tavangar (University of Isfahan)
    • Title: Some Results on Conditional Expectations of Ordered Random Variables
    • Place: M201
    • Time: 16:30-17:30
    • Abstract:
      In this talk, I will discuss about the mean past lifetime of a k-out-of-n system with identical components where it is assumed that the lifetimes of the components are independent and have a common distribution function F. Also we will propose a measure for obtaining the expectation of time between two lower k-records under the condition that the greater one is given. Several properties of the proposed measures are derived. Some characterization results and stochastic comparisons based on these measures are also provided.
  • 15 Mayıs 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: İlham Aliyev
    • Title: Birkaç klasik eşitsizlik ve uygulamaları
    • Place: C507
    • Time: 13:30-15:20
    • Abstract:
      Büyük ölçüde Lisans ve Yüksek Lisans öğrencilerine hitap edecek olan bu konuşmada ortalamalar arasındaki eşitsizliklerin yanısıra, Jensen, Çebişev v.b. ünlü eşitsizlikler ele alınarak, onların ekstremum problemlerine, denklem çözümüne, serilerin yakınsama problemine çeşitli uygulamaları verilecektir.
  • GRADUATE SEMINARS:
    • Date: May 13, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Place: C301
    • Time: 15:30-17:00
    • Speaker: Cihangir Kan
    • Title: The Signature of Coherent Systems
    • Abstract:
      The signature of a coherent system has been found to be a useful tool in various applications including the evaluation of reliability characteristics of systems, and the comparison of the performance of complex systems. In this study, the signatures of consecutive k-out-of n:F systems are calculated and the reliability properties of consecutive k-within-m-out-of-n:F systems with exchangeable components are studied. Monte Carlo estimator of system signature is obtained and used to approximate the survival function.
    • Speaker: Kerem Türkyılmaz
    • Title: Robust Estimation For Normal Distribution
    • Abstract:
      Robust estimations for normal distribution in single outlier model is investigated, numerical results and Bias and MSE tables of these estimators are obtained. Moreover, probability of rth order statistic to become outlier is derived. A robust estimator based on this probability is provided and MSE, Bias results of this estimator of mean for normal distribution are presented.
  • May 8, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Uğur Madran
    • Title: Reynolds Operator and Transfer Homomorphism as an Alternative
    • Place: C507
    • Time: 13:30-14:20
    • Abstract:
      In this talk, we will analyze properties of Reynolds operator for finite groups and will try to extend it to modular case. Examples and applications will also be discussed with emphasis on some advantages and disadvantages.
  • April 27, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Ülkü Gürler (Bilkent University)
    • Title: (Q,r) Inventory Policy with Perishable Products
    • Place: M201
    • Time: 16:30-17:30
    • Abstract:
      In this talk the (Q, r) ordering policy will be discussed for an inventory model with perishable items and positive lead times. It is assumed that the demand follows a Poisson process and the shelflife is a constant. Under the (Q, r) ordering policy the inventory level process at the instances when the stock hits the level Q constitutes an embedded Markov process. Although the shelflives are constant, the sequence of remaining shelflives of the items at the instances where stock level is Q is a random sequence. The limiting distribution of this sequence is obtained and the long run expected cost rate function is derived based on this limiting distribution.

      Numerical results and extensions of the model will also be presented.

  • April 20, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: İsmihan Bayramoğlu
    • Title: Conditional Expectations with respect to σ-Algebras
    • Place: C509
    • Time: 16:30-17:30
    • Abstract:
      The concept of conditional expectation with respect to σ-algebras will be considered. Properties and applications will be discussed in detail.
  • April 15, 2009
    • Poster: As a pdf document.
    • Speaker: Uğur Madran
    • Title: Writing Scientific Papers with LATEX
    • Place: M207
    • Time: 14:30-15:20
    • Abstract:
      Powerful and popular document preparation system LaTeX will be introduced. This talk is aimed at graduate and senior students for writing their thesis and project reports.
  • April 10, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Erdal Karapınar (Atılım University)
    • Title: On Classifications of Sequence Spaces
    • Place: M205
    • Time: 13:30-14:30
    • Abstract:
      Classifications of Sequence Spaces were considered by many authors, e.g., A.Aytuna, P.Chalov, P.Djakov, A. Goncarov, M. Kocatepe, B.Mityagin, Z.Nurlu, S.Önal, M.Yurdakul, T.Terzioğlu, Vogt, Zakharyuta and by many other authors. In this talk, only the Orlicz-Kothe-sequence spaces and isomorphic classifications of that sequence spaces are considered.
  • March 23, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Alexei Stepanov
    • Title: Generalization of Borel-Cantelli Lemma. Some Applications.
    • Place: M403.
    • Time: 16:30-17:30
    • Abstract:
      In the present report a generalization of Borel-Cantelli lemma is discussed. By above generalization, we obtain some strong limit results.
  • 16 Mart 2009
    • Poster: Seminer ilanı (pdf) ve posteri (png).
    • Konuşmacı: Ali Nesin (İstanbul Bilgi Üniversitesi)
    • Başlık: Sonsuzu Saymak
    • Yer: M01
    • Zaman: 16:30-17:20
  • March 09, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Murat Adıvar
    • Title: Existence results for periodic solutions of nonlinear system of integro-dynamic equations on time scales
    • Place: M309
    • Time: 16:30-17:30
    • Abstract:
      Using topological degree method and Schaefer's fixed point theorem, we deduce the existence of periodic solutions of nonlinear system of integro dynamic equations on periodic time scales. Furthermore, we provide several applications to scalar equations, where we develop a time scale analogue of Lyapunov's direct method and prove an analogue of Sobolev's inequality on time scales to arrive at a priori bound on all periodic solutions.
  • January 22, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Safar Parsi
    • Title: Progressive Censoring with dynamic withdrawals
    • Place: C501
    • Time: 11:00-12:00
    • Abstract:
      In life testing experiment under the setup of progressive Type II censoring we consider a new dynamic scheme, where the experimenter removes r1*(r1*≤ r1) units from the experiment if the first failure occurs before some predefined time t1, and removes r1 units when the first failure occurs after time t1. If the second failure occurs before the time t2, r2* surviving items are removed at random, otherwise r2 surviving units are removed, (r2*≤ r2), and so on; finally, after the mth failure, rm*= rm remaining items are removed. Under this setup of the experiment we study the distributions of failure times, which are entitled as dynamic progressive Type II censored (DPC) order statistics. The simulation algorithm for generating DPC samples and an illustrative example for a special case of exponential distribution are also presented.
  • January 7, 2009
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Ünal Ufuktepe
    • Title: Unifying Continuous and Discrete Analysis: Time Scale Analysis
    • Place: K202
    • Time: 16:30-17:30
    • Abstract:
      In this talk we give an introduction to the time scale calculus which is the unification of continuous and discrete analysis. We present various properties of exponential functions on a time scale and solve the first order the linear dynamic equations and and give some applications.
  • December 17, 2008
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Baruch Schneider
    • Title: Generalizing Complex Analysis to Many Dimensions
    • Place: A2
    • Time: 16:30-17:30
    • Abstract:
      Complex analysis is a beautiful subject with numerous applications in many different areas of mathematics and physics. The natural curiosity as well as further applications demand expansion of complex analysis to three and more dimensions. There are many reasons why several complex variables theory is not suitable as the right generalization. To get a different theory in higher dimensions we need more imaginary units, e.g. a Clifford algebra. This is the route of Clifford analysis.
  • 25 Kasım 2008
    • Poster: Duyuru (pdf dosyası).
    • Konuşmacı: Kadri Yakut (Cambridge Üniversitesi, Astronomi Enstitüsü)
    • Başlık: Evrenin ve Bileşenlerinin Fiziksel, Kimyasal ve Biyolojik Evrimi
    • Yer: Konferans Salonu
    • Zaman: 16:30-17:30
    • İçerik:
      Güneş sistemi, Güneş sistemi dışındaki gezegenler, Yıldızların evrimi, galaksiler, Kara delikler, Evrenin oluşumu ve gelişimi, evrende elementlerin evrimi, dünya dışı yaşam, vb.
    November 25, 2008

    Special theme: UN declared the coming year as International Year of Astronomy upon the recommendation of UNESCO. It is aimed to increase public awareness about developements and research in astronomy.
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Kadri Yakut (Institute of Astronomy, University of Cambridge)
    • Title: Physical, Chemical and Biological Evolution of the Universe and Its Components
    • Topics:
      Solar system, Planets from other solar systems, Evolution of Stars, Galaxies, Black Holes, Formation of the Universe and Its Development, Evolution of the Elements in the Universe, Extraterrestrial Life.
    N.B. This seminar will be in Turkish.
  • November 12, 2008
    • Poster: As a document (pdf) or as a poster (png) file.
    • Speaker: Serkan Eryılmaz
    • Title: RUNS: A COMBINATORIAL ANALYSIS
    • Abstract:
      Runs and run-related statistics have been effectively used for the analysis of sequential data appear in various fields such as statistical process control, reliability, and molecular biology. A variety of techniques have been used to obtain the distribution of runs in the literature.

      In this talk, the method of combinatorial analysis for finding the exact distribution of runs is presented and the results are illustrated for various binary sequences.