Yazar "Bıyıkoğlu, Türker" için FEF - Makale Koleksiyonu | Matematik Bölümü / Department of Mathematics listeleme
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Algebraic connectivity and degree sequences of trees
Bıyıkoğlu, Türker; Leydold, Josef (Elsevier Science Inc, 2009-01-15)We investigate the structure of trees that have minimal algebraic connectivity among all trees with a given degree sequence. We show that such trees are caterpillars and that the vertex degrees are non-decreasing on every ... -
Cryptanalysis of Fridrich's chaotic image encryption
Solak, Ercan; Çokal, Cahit; Yıldız, Olcay Taner; Bıyıkoğlu, Türker (World Scientific Publishing, 2010-05)We cryptanalyze Fridrich's chaotic image encryption algorithm. We show that the algebraic weaknesses of the algorithm make it vulnerable against chosen-ciphertext attacks. We propose an attack that reveals the secret ... -
Dendrimers are the unique chemical trees with maximum spectral radius
Bıyıkoğlu, Türker; Leydold, Josef (Univ Kragujevac, 2012)It is shown that dendrimers have maximum spectral radius and maximum Collatz-Sinogowitz index among all chemical trees of given size. The result is also generalized for the class of chemical trees with prescribed number ... -
Discovering cis-regulatory modules by optimizing barbecues
Mosig, Axel; Bıyıkoğlu, Türker; Prohaska, Sonja J.; Stadler, Peter F. (Elsevier Science Bv, 2009-05-28)Gene expression in eukaryotic cells is regulated by a complex network of interactions, in which transcription factors and their binding sites on the genomic DNA play a determining role. As transcription factors rarely, if ... -
Four-cycled graphs with topological applications
Bıyıkoğlu, Türker; Civan, Yusuf (Birkhauser Verlag AG, 2012-03)We call a simple graph G a 4-cycled graph if either it has no edges or every edge of it is contained in an induced 4-cycle of G. Our interest on 4-cycled graphs is motivated by the fact that their clique complexes play an ... -
Geometric representations and symmetries of graphs, maps and other discrete structures and applications in science
Bıyıkoğlu, Türker; Özkahya, Lale (Tübitak, 2015-09)Bu proje çalışmasının birinci amacı çizgelerin özdeğer ve özvektör yapılarını çizge özellik ve sabitleri ile ilişkilendirmektir. İkinci amacı biyoloji, bioinformatik, dinamik sistemler, haberleşme, kriptoloji ve sosyal ... -
Graphs of given order and size and minimum algebraic connectivity
Bıyıkoğlu, Türker; Leydold, Josef (Elsevier Science Inc, 2012-04-01)The structure of connected graphs of given size and order that have minimal algebraic connectivity is investigated. It is shown that they must consist of a chain of cliques. Moreover, an upper bound for the number of maximal ... -
Graphs with given degree sequence and maximal spectral radius
Bıyıkoğlu, Türker; Leydold, Josef (Electronic Journal of Combinatorics, 2008-09-15)We describe the structure of those graphs that have largest spectral radius in the class of all connected graphs with a given degree sequence. We show that in such a graph the degree sequence is non-increasing with respect ... -
Laplacian Eigenvectors of graphs
Bıyıkoğlu, Türker; Leydold, Josef; Stadler, Peter F. (Springer Verlag, 2007)[No abstract available] -
Largest eigenvalues of the discrete p-Laplacian of trees with degree sequences
Bıyıkoğlu, Türker; Hellmuth, Marc; Leydold, Josef (Int Linear Algebra Soc, 2009-03)Trees that have greatest maximum p-Laplacian eigenvalue among all trees with a given degree sequence are characterized. It is shown that such extremal trees can be obtained by breadth-first search where the vertex degrees ... -
Network synchronization: Spectral versus statistical properties
Atay, Fatihcan Mehmet; Bıyıkoğlu, Türker; Jost, Jürgen (Elsevier B.V., 2006-12)We consider synchronization of weighted networks, possibly with asymmetrical connections. Focusing on causal relations rather than the observed correlations, we show that the synchronizability of networks cannot be directly ... -
Semiregular trees with minimal Laplacian spectral radius
Bıyıkoğlu, Türker; Leydold, Josef (Elsevier Inc, 2010-04-15)A semiregular tree is a tree where all non-pendant vertices have the same degree. Among all semiregular trees with fixed order and degree, a graph with minimal (adjacency/Laplacian) spectral radius is a caterpillar. Counter ... -
Some notes on spectra of cographs
Bıyıkoğlu, Türker; Simic, Slobodan K.; Stanic, Zoran (Charles Babbage Res Ctr, 2011-07)A cograph is a P-4-free graph. We first give a short proof of the fact that 0 (-1) belongs to the spectrum of a connected cograph (with at least two vertices) if and only if it contains duplicate (resp. coduplicate) vertices. ...