Turker Biyikoglu

Graph Theory and its Applications Group - Senior Researcher
 
My research interests include graph theory, graph modelling and graph applications.

Short vita
 
I got my diploma degree in mathematics in 2000 under the supervision of Gerhard J Woeginger from the TU Graz (Austria) and my Ph.D. degree in 2003 under the supervision of Peter F. Stadler and Josef Leydold from the University of Vienna (Austria).
 
I was a two years postdoctoral fellow at the Max Planck Institute for Mathematics in the Sciences in Leipzig (Germany) and a one year postdoctoral fellow at the Department of Mathematical Engineering Universite Catholique de Louvain (Belgium). I was  more than six years  associate professor at the Department of Mathematics of Isik University, Istanbul and Department of Mathematics Izmir Institute of Technology, Izmir (Turkey). Last seven years, I was senior scientist at two start-up companies in Ankara.

Awards
 
Türk Matematik Vakfı (Turkish Mathematical Foundation) - Masatoshi Gündüz İkeda Research Award, 2015
 
Distinguished Young Scholar Award, Turkish Academy of Sciences, 2009 (TUBA-GEBIP/2009)

Research Projects with funds

 
“Geometric representations and symmetries of graphs, maps and other
 discrete structures and applications in science” (GReGAS) supported
 by TUBITAK and the European Science Foundation (EUROCORES
 Programme EUROGIGA), 2011-2014, Principal Researcher.
Lale Ozkahya (post-doc)
 
 “Castelnuovo-Mumford Regularity of Graphs and Topology of De
cycling Complexes” supported by TUBITAK, 2012-2014. This is a
 joint project with Yusuf Civan (Suleyman Demirel University, Isparta,
 Turkey).

 “Bionetalign: Global Alignment of Biochemical Networks Regularity
 for Functional Orthology” supported by TUBITAK 2012-2014. This
 is a joint project with Cesim Erten (Kadir Has University Istanbul,
 Turkey).

Publications

 
Book
T. Biyikoglu, J. Leydold and P. F. Stadler, Laplacian Eigenvectors of Graphs,
Lecture Notes in Mathematics 1915, Springer (2007).
 
Journal Publications
F. Alkan, T. Biyikoglu, M. Demange and C. Erten, Structure of conflict graphs in constraint alignment problems and algorithms, 
Discrete Mathematics & Theoretical Computer Science, 21 no.4 Sep 11 (2019).

T. Biyikoglu and Y. Civan, Prime Graphs, Matching and the Castelnuovo-Mumford Regularity, J. Commutative Algebra, 11: 1-27 (2019).
 
T. Biyikoglu and Y. Civan, Castelnuovo-Mumford Regularity of Graphs, Combinatorica, 38: 1353-1383 (2018).
 
T. Biyikoglu and Y. Civan, Vertex Decomposable Graphs, Codismantlability, Cohen-Macaulayness and Castelnuovo-Mumford Regularity,
 Electronic Journal of Combinatorics, 21: #P1.1 (2014).

 G. Abaka, T. Biyikoglu, C. Erten, CAMPways: constrained alignment framework for the comparative analysis of a pair of metabolic pathways,
 Bioinformatics, 29: 145-153 (2013).

T. Biyikoglu and Y. Civan, Four-cycled graphs with topological applications, Annals of Combinatorics, 16: 37-56 (2012).

T. Biyikoglu and J. Leydold, Dendrimers are the unique chemical trees with maximum spectral radius, 
MATCH Communications in Mathematical and in Computer Chemistry, 68: 851-854 (2012).

T. Biyikoglu and J. Leydold, Graphs of given order and size and minimum algebraic connectivity, 
Linear Algebra and its Applications, 436: 2067-2077 (2012).

T. Biyikoglu, S. Simic, Z. Stanic, Some Notes on Spectra of Cographs, Ars Combinatoria, 100: 421-434 (2011).

E. Solak, C. Cokal, O.T. Yildiz, T. Biyikoglu, Cryptanalysis of Fridrich’s image encryption, International Journal of Bifurcation and Chaos, 20:
 1405-1413 (2010).
  
T. Biyikoglu and J. Leydold, Semiregular trees with minimal Laplacian spectral radius, 
Linear Algebra and its Applications, 432: 2335-2341 (2010).

 A. Mosig, T. Biyikoglu, S.J. Prohaska, and P.F. Stadler, Discovering Cis-Regulatory Modules by optimizing Barbecues, Discrete Applied
 Mathematics, 157: 2458-2468 (2009).

T. Biyikoglu, M. Hellmuth, and J Leydold, Largest Eigenvalues of  the Discrete p-Laplacian of Trees with Degree Sequences, Electronic
Journal of Linear Algebra, 18: 202-210 (2009).

T. Biyikoglu and J. Leydold, Algebraic Connectivity and Degree Sequences of Trees, Linear Algebra and its Applications, 430: 811-817
 (2009).

T. Biyikoglu and J. Leydold, Graphs with given degree sequence and maximal spectral radius, 
Electronic Journal of Combinatorics, 15: R119 (2008).

T. Biyikoglu and J. Leydold, Faber-Krahn Type Inequalities for Trees, Journal of Combinatorial Theory, Series B., 97: 159-174 (2007).
 
F. M. Atay, T. Biyikoglu, J. Jost, Network synchronization: Spectral versus statistical properties, Physica D, 224: 35-41 (2006).

F. M. Atay, T. Biyikoglu, J. Jost, Synchronization of Networks with Prescribed Degree Distributions, IEEE Transactions on Circuits and
 Systems I, 53: 92-98 (2006).

F. M. Atay, T. Biyikoglu, Synchronization of Complex Networks under Graph Operations, Physical Review E, 72: 016217 (2005).
 
T. Biyikoglu, J. Leydold, and P. F. Stadler, Nodal Domains and Bipartite Subgraphs, Electronic Journal of Linear Algebra, 13: 344-351
 (2005).

T. Biyikoglu, Degree sequences of Halin graphs and forcibly cograph graphic sequences, Ars Combinatoria, 75: 205-210 (2005).
 
T. Biyikoglu, W. Hordijk, J. Leydold, T. Pisanski, P. F. Stadler, Graph Laplacians, Nodal Domain, and Hyperplane Arrangements, 
Linear Algebra and its Applications, 390: 155-174 (2004).
 
T. Biyikoglu, A Discrete Nodal Domain Theorem for Trees, Linear Algebra and its Appications, 360: 197-205 (2003).

T. Biyikoglu, A counterexample to a conjecture of Erd˝os, Discrete Mathematics, 250: 231-232 (2002)

Conference Proceedings
 
S. Baksi, O. Kaya and T. Biyikoglu, Enabling Cooperation, Resource Allocation and Receiver Selection Across Cells: Complementary Fractional Frequency Reuse. IEEE PIMRC 2013, London, UK, Sept. 2013.

 S. Baksi, O. Kaya, T. Biyikoglu, Optimal and Near-optimal Partner Selection Algorithms in Cooperative OFDMA, IEEE WCNC 2012, Paris, France, April 2012.

Preprints
 
T. Biyikoglu and Y. Civan, Bounding the collapsibility number of simplicial complexes and graphs, Preprint (2023). [pdf]

T. Biyikoglu and Y. Civan, Projective dimension of (hyper)graphs and the Castelnuovo-Mumford regularity of bipartite graphs, Preprint (2016). [pdf]
 
T. Biyikoglu and Y. Civan, A note on the recognition of codismantlable graphs and posets, Preprint (2016). [pdf]

T. Biyikoglu and Y. Civan,  Bounding Castelnuovo-Mumford regularity of graphs via Lozin's transformation,  Preprint (2013). [pdf]

T. Biyikoglu, and J Leydold,  Semiregular Trees with Minimal Index, Preprint (2009). [pdf]

T. Biyikoglu, M. Hellmuth, J Leydold, Largest Laplacian Eigenvalue and Degree Sequences of Trees, Preprint (2007). [pdf]

T. Biyikoglu; Rank and number of nodal domains of cographs; Preprint (2002). [ps]

In Preperation
 
T. Biyikoglu, Y. Civan, M. Demir and H. G¨uler, Helly number, domination and homology, submitted (2024).
 
J. Allmer, T. Biyikoglu and C. Has, De Novo Sequencing of Tandem Mass Spectra using a Novel Graph Modeling Approach, in preparation.
 
F. M. Atay and T. Biyikoglu, Graph entropy, degree assortativity, and hierarchical structures in networks, in preparation.

Industrial Research
I was founding partner of a consulting company between 2015 and 2017. We have developed research driven steam flow forecasting models and products specially 
for Turkish hydroelectric power plant sector.  

Seminar and Workshop Organization
Monthly Istanbul Discrete Mathematics Meetings, Istanbul Center for Mathematical Sciences, Bo˘gazi¸ci University, 2009-2012 (with T. Ekim).
Workshop on Graph Theory and its Applications I, II, III, Istanbul, 2010, 2011 and 2012 (with T. Ekim).

Service
Guest editor of Turkish popular mathematics journal ”Matematik D¨ unyası”, 2017–2020.
Saytın xəritəsi Əlaqə
Əlaqə
Baku State University, main building, 3rd floor, Digital State Research Laboratory, Baku city, academician Zahid Khalilov street, 33, AZ 1148
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