Publications

Articles in international peer-reviewed journals

• Heuristics for Biquadratic Assignment Problems and their Computational Comparison ,
  with R.E. Burkard,
  European Journal of Operational Research 83, 1995, 283-300.
• A Minimax Assignment Problem in Treelike Communication Networks,
  with R.E.Burkard and G.J. Woeginger,
  European Journal of Operational Research 87, 1995, 670-684.
• Hamiltonian Cycles in Circulant Digraphs with Two Stripes,
  with R.E. Burkard, G.J. Woeginger, and Q.F. Yang,
  Discrete Mathematics 176, 1997, 233-254.
• The Quadratic Assignment Problem with a Monotone Anti-Monge Matrix and a Symmetric Toeplitz Matrix: Easy and Hard Cases,
  with R.E. Burkard, G. Rote, and G.J. Woeginger,
  Mathematical Programming (Series B), 82, 1998, 125-158.
• A Unified Approach to Simple Special Cases of Extremal Permutation Problems ,
  with R.E. Burkard, V. M. Demidenko, N.N. Metelski, and G.J. Woeginger,
  Optimization 44, 1998, 123-138. DOI.
• Stochastic Algorithms in Electromagnetic Optimization,
  with G. Alotto, B. Brandstätter, G. Fürntratt, Ch. Magele, G. Molinari, M. Nervi, K. Preis, M. Repetto, and K. Richter,
  IEEE Transactions on Magnetics 34, 1998, 3674-3684.
• A Dual Framework for Lower Bounds of the Quadratic Assignment Problem Based on Linearization,
  with S.E. Karisch, J. Clausen, and T. Espersen,
  Computing 63, 1999, 351-403.
• 2-Medians in trees with pos/neg  weights ,
  with R.E. Burkard and H. Dollani,
  Discrete Applied Mathematics, 105, 2000, 51-71.
• An asymptotical study of combinatorial optimization problems by means of statistical mechanics,
  with H. Albrecher and R.E. Burkard,
  Journal of Computational and Applied Mathematics, 186(1), 2006, 148-162. DOI.
• Polynomially solvable cases of the constant rank unconstrained quadratic 0-1 programming problem,
  with B. Klinz and Ch. Meyer,
  Journal of Combinatorial Optimization, 12(3), 2006, 187-215. DOI.
• The Wiener maximum quadratic assignment problem,
  with N.S. Schmuck, S. Wimer and G.J. Woeginger,
  Discrete Optimization 8(3), 2011, 411-416. DOI.
• Another well-solvable case of the QAP: Maximizing the job completion time variance,
  with V. Deineko and G.J. Woeginger,
  Operations Research Letters 40, 2012, 356-359. DOI.
• On x-and-y axes travelling salesman problem,
  with V. Deineko and G.J. Woeginger,
  European Journal of Operational Research 223, 2012, 333-345. DOI.
• Linearizable special cases of the QAP,
  with V. Deineko and G.J. Woeginger, Journal of Combinatorial Optimization 31(3), 2016, 1269-1279. DOI.
  
• Heuristics for the data arrangement problem on regular trees ,
  with R. Staněk ,
  Journal of Combinatorial Optimization 30(3), 2015, 768-802. DOI.
• Well-solvable cases of the QAP with block-structured matrices,
  with V. Deineko and G.J. Woeginger,
  Discrete Applied Mathematics 186, 2015, 56-65. DOI.
  
• Optimization Approach to Handle Global CO2 Fleet Emission Standards, with M. Martin and A. Eichberger,
  SAE Technical Paper 2016-01-0904, 2016. DOI.
• The multi-stripe travelling salesman problem,
  with V. Deineko and G.J. Woeginger,
  Annals of Operations Research 259, 2017, 21-34.
  DOI.
• New special cases of the Quadratic Assignment Problem with diagonally structured coefficient matrices,
  with V. Deineko and G.J. Woeginger,
  European Journal of Operational Research 267(3), 2018, 818-834.
• Mean-variance portfolio optimization based on ordinal information,
  with S. Hafner, R. Mestel, and U. Pferschy,
  Journal of Banking and Finance 122, 2021, Article 105989.
• A Machine Learning Based Branch and Price Algorithm for a Sampled Vehicle Routing Problem,
  with Nikolaus Furian, Michael O'Sullivan, Cameron Walker,
  OR Spectrum , 43(3), 2021, 693-732, DOI
• Monotonic Representations of Outerplanar Graphs as Edge Intersection Graphs of Paths on a Grid,
  with E. Gaar,
  Journal of Graph Algorithms and Applications 26(4), 2022, 519--552. arXiv, DOI
• Relationship of k-Bend and Monotonic l-Bend Edge Intersection Graphs of Paths on a Grid,
  with E. Gaar,
  Discrete Applied Mathematics 331, 2023, 88--103. DOI , arXiv
• Recognising permuted Demidenko matrices,
  with V. Deineko and G.J. Woeginger,
  Operations Research Letters 51, 2023, 494-500, DOI, arXiv.
• Travelling salesman paths on Demidenko matrices,
  with V.G. Deineko and G.J. Woeginger,
  Discrete Applied Mathematics, 354, 2024, 3--14. arXiv, DOI
• Special Cases of the Minimum Spanning Tree Problem under Explorable Edge and Vertex Uncertainty,
  with C. Mathwieser,
  Networks 2024, DOI, arXiv.
• A linear time algorithm for linearizing quadratic and higher-order shortest path problems,
  with B. Klinz, S. Lendl, G.J. Woeginger, and L. Wulf,
  Mathematical Programming 2024, DOI, arXiv.
• Integrating multiple sources of ordinal information in portfolio optimization,
  with S. Hafner, R. Mestel and U. Pferschy,
  Annals of Operations Research 346, 2025, 1967-1995, DOI, arXiv.

Book chapters and articles in conference proceedings

• On the Biquadratic Assignment Problem,
  with R.E. Burkard and B. Klinz,
  in Quadratic Assignment and Related Problems,
  Proceedings of the DIMACS Workshop on Quadratic Assignment Problems,
  P. Pardalos and H. Wolkowitz, eds.,
  DIMACS Series in Discrete Mathematics and Theoretical Computer Science 16, 1994, 117-146.
• A Communication Assignment Problem on Trees: Heuristics and Asymptotic Behavior ,
  with R.E. Burkard and T. Dudas,
  in Network Optimization, P.M. Pardalos, D.W. Hearn, and W.W. Hager, eds.,
  Lecture Notes in Economics and Mathematical Systems 450, 1997, 127-156.
• Quadratic and Three-Dimensional Assignments: An Annotated Bibliography,
  with R.E. Burkard,
  in Annotated Bibliographies in Combinatorial Optimization,
  M. Dell'Amico, F. Maffioli and S. Martello, eds.,
  Wiley, Chichester, 1997, pp. 373-392.
• The Quadratic Assignment Problem,
  with R.E. Burkard, P.M. Pardalos, and L.S. Pitsoulis,
  Handbook of Combinatorial Optimization, P.M. Pardalos and D.-Z. Du, eds.,
  Kluwer Academic Publishers, 1998, pp. 241-338. DOI.
• Linear Assignment Problems and Extensions,
  with R.E. Burkard,
  Handbook of Combinatorial Optimization - Supplement Volume A,
  P.M. Pardalos and D.-Z. Du, eds.,
  Kluwer Academic Publishers, 1999, pp. 75-149. DOI.
• Assignment Problems,
  Handbook of Applied Optimization, Part II - Applications,
  P.M. Pardalos and M. Resende, eds.,
  Oxford University Press, 2002, pp. 661-678.
• A new tractable case of the QAP with a Robinson matrix,
  with V. Deineko and G.J. Woeginger,
  in Combinatorial Optimization and Applications, Z. Lu et al., eds.,
  Proceedings of the 9th International Conference on Combinatorial Optimization and Applications (COCOA'2015),
  LNCS 9486, 2015, Springer, pp. 709-720. DOI.
• Linearizable special cases of the quadratic shortest path problem,
  with Bettina Klinz, Stefan Lendl, James Orlin, Gerhard J. Woeginger and Lasse Wulf,
  in Graph Theoretic Concepts in Computer Science: WG 2021, L. Kowalik, M. Pilipczuk and P. Rzazewski, (Hrsg.),
  Lecture Notes in Computer Science 12911, 2021, 245-256. DOI
• Complexity and Polynomially Solvable Special Cases of QUBO
  with A.P. Punnen,
  in The Quadratic Unconstrained Binary Optimization Problem: Theory, Algorithms, and Applications,
  A.P. Punnen, ed., 2022, Springer Nature Switzerland AG, 57-95.
  DOI.
• A linear time algorithm for linearizing quadratic and higher-order shortest path problems,
  with Bettina Klinz, Stefan Lendl, Gerhard J. Woeginger and Lasse Wulf,
  in Integer Programming and Combinatorial Optimization, 24th International Conference, IPCO 2023 , A. Del Pia and V. Kaibel, (Hrsg.),
  Lecture Notes in Computer Science 13904, 2023, 466-479. DOI

Submitted for publication

• The data arrangement problem on binary trees, with J. Schauer and R. Staněk, arXiv

Monograph

Diploma, doctoral, and habilitation theses

• Diploma Thesis:
  Complexity comparison and analysis of recent algorithms for network flows (1992), in Albanian.
• PhD Thesis:
  The Quadratic Assignment Problem: Special Cases and Relatives (1995).
• Habilitation Thesis:
  NP-hard location problems: efficiently solvable special cases and lower bounds (2001).

Test instances