**Our key research focus areas include**

- Linear, integer, and nonlinear optimization
- Network theory and network design
- Algorithms
- Metaheuristics
- Multi-criteria decision making
- Stochastic processes
- Queueing theory
- Stochastic programming
- Forecasting models
- Military operations research

**Members of the research group**

- Z. Müge Avşar
- Meral Azizoğlu
- İsmail Serdar Bakal
- Sakine Batun
- Pelin Bayındır
- Serhan Duran
- Sinan Gürel
- Cem İyigün
- Esra Karasakal
- Gülser Köksal
- Nur Evin Özdemirel
- Seçil Savaşaneril
- Mustafa Kemal Tural

**Selected projects **

- Elektronik Harp ve Radar, Sektör Kabiliyet Atlası, Döner Sermaye Projesi, STM, July 2019 - February 2020. Team Member(s): Tural M.K.
- Türkiye Zeytinyağı Endüstrisinde Karar Problemleri (Decision Problems in Turkish Olive Oil Industry), METU-BAP-07-02-2017-004-067, Lisansüstü Tez Projesi, January 2017 - December 2017. Team member(s): Meral S., Balkan B.A.

- Çok Kriterli Tam Sayılı Optimizasyon Problemlerinde Tüm Etkin Çözümlerin Bulunması için Yaklaşımlar, METU BAP-08-11-2016-70, 2016 - Ongoing. Team member(s): Karakaya G. (Project Director), Köksalan M. (Researcher)

- Belirsizlik Halindeki Bozulmuş Ağlarda Öğrenme ve Optimizasyon Ödünleşimi (Learning and Optimization Trade-Off in Disrupted Networks under Uncertainty), TÜBİTAK 2232, March 2016 - March 2018. Team Member(s): Çelik M.

- Collaborative Research: Resource Allocation with Learning in Dynamic and Partially Observable Networks, NSF CMMI-1538860, January 2016 - December 2018. Team member(s): Keskinocak P., Çelik M., Ergun Ö.

- Çok Amaçlı Tamsayı Problemlerinde Baskın Çözümler Üzerine: Analizler Yaklaşımlar ve Uygulamalar (Nondominated Points of Multi-objective Integer Programming Problems: Analysis Approaches and Applications), TÜBİTAK 1001, March 2016 - December 2018. Team member(s): Lokman B., Köksalan M., Ceyhan G., Doğan I., Özarık S. S.

- Belirsizlik Altında Esnek Tesis Yerleşimi için Yenilikçi Yaklaşımlar, METU BAP-03-07-2015-002, January 2015 - December 2015. Team member(s): Süral H., Çelik M., Efeoğlu B.
- Interactive Approaches for Bi-Objective UAV Route Planning in Continuous Space, AF Office of Scientific Research, 2015 - Ongoing. Team member(s): Köksalan M., Tezcaner-Öztürk C., Türeci H., Bakan Ş.
- HERİKKS Harp Yönetimi Yazılımı – Füze Tehdit Değerlendirme ve Silah Tahsis (F-TDST) Projesi (Missile Target-Weapon Allocation in Air Defense for ASELSAN, ASELSAN, March 2015 - August 2015. Team member(s): Kırca Ö., Köksal G., Dinler D., Gökayaz G., Kemikli G.
- Minimum Ağırlıklı Maksimum Eşleme Problemi için Polihedral Yaklaşımlar, METU BAP-08-11-2014-006, January 2015 - December 2015. Team member(s): Tural M.K.
- Çok Amaçlı Ürün ve Süreç Tasarımı Optimizasyonu için Etkileşimli Yaklaşımlar, METU BAP-03-07-2014-002, January 2014 - December 2015. Team member(s): Köksalan M., Köksal G., Özateş M.
- Çok Amaçlı Sıralama Problemleri için Etkileşimli ve Olasılıklı Yaklaşımlar, BAP-03-07-2014-001, January 2014 - December 2014. Team member(s): Serin Y., Köksalan M., Mutlu S.
- Optimizasyon ve Genel Denge Modelleri Aracılığı ile Çok Amaçlı Enerji ve Çevre Politikaları Analizi, METU BAP-08-11-2014-019, January 2014 - December 2014. Team member(s): Köksalan M., Voyvoda E., Yıldız Ş.
- CONCOORD - Consolidation and Coordination in Urban Areas - Joint Programming Initiative Urban Europe, April 2013 - Ongoing. Team member(s): Süral H., İyigün C., Gürel S., Kunter U.C., Farham M.S., Pancaroğlu M. Project Partners: Eindhoven University of Technology, University of Twente, Technical University Denmark, Vienna University of Economics and Busin.
- Substitution Policies and an Analysis of Benefit of Substitution for Manufacturers, TÜBİTAK-112M431, June 2012 - March 2014. Team member(s): Savaşaneril S., Töre N.
- Havayolu Taşımacılığında Çizelge Aksaklıkları Yönetimi, METU BAP-08-11-2011-125, January 2011 - Ongoing. Team member(s): Gürel S., Arıkan U.
- Etkin Radar Silah Yerleşim Planlama Algoritmasının Geliştirilmesi, ASELSAN, December 2014 - June 2015. Team member(s): İyigün C., Limon Y.
- Development of Performance Based Project Management Decision Support System for Construction Project Consultancy Companies, ES Proje, June 2014 - June 2015. Team member(s): Duran S.
- Smart Energy Aware Systems – Development of Optimization Models to be Integrated in Smart Home Systems, INNOVA, August 2014 - August 2015. Team member(s): Duran S., İyigün C.

**Selected publications**

- Tural M. K. (2019), Valid inequalities for the maximal matching polytope, Adıyaman Üniversitesi Fen Bilimleri Dergisi, 9(2), pp 374-385.
- Ak M., Kentel E., Savaşaneril S. (2019), Quantifying the revenue gain of operating a cascade hydropower plant system as a pumped-storage hydropower system, Renewable Energy, 139, pp 739-752.
- Bülbül P., Bayındır Z. P., Bakal İ. S. (2019), Exact and heuristic approaches for joint maintenance and spare parts planning, Computers and Industrial Engineering, 129, pp 239-250.
- Ceyhan G., Köksalan M., Lokman B. (2019), Finding a representative nondominated set for multi-objective mixed ınterger programs, European Journal of Operational Research, 272(1), pp 61-77.
- Karasakal E., Karasakal O., Bozkurt A. (2019), An approach for extending promethee to reflect choice behaviour of the decision maker, Endüstri Mühendisliği Dergisi, 30(2), pp 123-140.
- Karsu Ö., Azizoğlu M. (2019), An exact algorithm for the minimum squared load assignment problem, Computers and Operations Research, 10, pp 76-90.
- Selçuk A. M., Avşar Z. M. (2019), Dynamic pricing in airline revenue management, Journal of Mathematical Analysis and Applications, 478, pp 1191-1217.
- Terciyanlı E., Avşar Z. M. (2019), Alternative risk-averse approaches for airline network revenue management, Transportation Research Part E: Logistics and Transportation Review, 125, pp 27-46.
- Akteke-Öztürk B., Köksal G., Weber G.W. (2018), Nonconvex optimization of desirability functions, Quality Engineering, 30(2), pp 293-310 .

- Eroğlu E. , Azizoğlu M. (2018), Exact approaches for the directed bi-objective Chinese postman problem, Endüstri Mühendisliği , 29, pp 15-30 .

- Karakaya G., Köksalan M. (2018), Interactive approaches for bi-objective problems with progressively-changing solution sets, International Transactions in Operational Research, 25(3) , pp 1027-1052 .

- Karakaya G., Köksalan M., Ahıpaşaoğlu S. D. (2018), Interactive algorithms for a broad underlying family of preference functions, European Journal of Operational Research, 265(1), pp 248-262 .

- Lokman B., Köksalan M., Korhonen P. J., Wallenius J. (2018), An interactive approximation algorithm for multi-objective integer programs, Computers & Operations Research, 96, pp 80-90 .

- Tural Hesapçıoğlu S., Tural M. K. (2018), Prevalence of peer bullying in secondary education and its relation with high school entrance scores, Düşünen Adam-Journal of Psychiatry and Neurological Sciences, 31, pp 347-355 .

- Yörükoğlu S., Avşar Z. M., Kat B. (2018), An integrated day-ahead market clearing model: incorporating paradoxically rejected/accepted orders and a case study, Electric Power Systems Research, 163, pp 513-522 .

- Ak M.K., Erdoğan E., Savaşaneril S. (2017), Operating policies for energy generation and revenue management in single-reservoir hydropower systems, Renewable and Sustainable Energy Reviews, 78, pp 1253.

- Çağlar M., Gürel S. (2017), Public R&D project portfolio sSelection problem with cancellations, OR Spectrum, 39, pp 659-687.

- Çelik M. (2017), Network restoration and recovery in humanitarian operations: Framework, literature review, and research directions, Surveys in Operations Research and Management Science, 21(2), pp 47-61.

- Karasakal E., Aker P. (2017), A multicriteria sorting approach based on data envelopment analysis for R&D project selection problem, Omega, 73, pp 79-92

- Köksalan M., Mousseau V., Özpeynirci S. (2017), Multi-criteria sorting with category size restrictions, International Journal of Information Technology & Decision Making, 16(1), pp 5-23.

- Köksalan M., Tezcaner Öztürk D. (2017), An evolutionary approach to generalized biobjective traveling salesperson problem, Computers & Operations Research, 79, pp 304-313.

- Arıkan U., Gürel S., Aktürk M.S. (2016), Integrated aircraft and passenger recovery with cruise time controllability, Annals of Operations Research, 236(2), pp 295-317.

- Dinler D., Tural M.K. (2016), A minisum location problem with regional demand considering farthest euclidean distances, Optimization Methods and Software, 31(3), pp 446-470

- Karakaya G., Köksalan M. (2016), An interactive approach for bi-attribute multi-item auctions, Annals of Operations Research, 245, pp 97-119.

- Karasakal E., Silav A. (2016), A multi-objective genetic algorithm for a bi-objective facility location problem with partial coverage, TOP, 24(1), pp 206-232.

- Köksalan M., Şakar C.T. (2016), An interactive approach to stochastic programming-based portfolio optimization, Annals of Operations Research, 245, pp 47-66.

- Lokman B., Köksalan M., Korhonen P., Wallenius J. (2016), An interactive algorithm to find the most preferred solution of multi-objective integer programs, Annals of Operations Research, 245, pp 67-95.

- Tezcaner Öztürk D., Köksalan M. (2016), An interactive approach for biobjective integer programs under quasiconvex preference functions, Annals of Operations Research, 244(2), pp 677-696.

- Tural, M.K. (2016), Maximal matching polytope in trees, Optimization Methods and Software, 31(3), pp 471-478.

- Arıkan U., Gürel S., Aktürk M.S. (2016), Integrated aircraft and passenger recovery with cruise time controllability,
*Annals of Operations Research*, 236(2), pp 295-317. - Dinler D., Tural M.K. (2016), A minisum location problem with regional demand considering farthest euclidean distances,
*Optimization Methods and Software*, 31(3), pp 446-470. - Karakaya G., Köksalan M. (2016), An interactive approach for bi-attribute multi-item auctions,
*Annals of Operations Research*, 245, pp 97-119. - Karasakal E., Silav A. (2016), A multi-objective genetic algorithm for a bi-objective facility location problem with partial coverage,
*TOP*, 24(1), pp 206-232. - Köksalan M., Şakar C.T. (2016), An interactive approach to stochastic programming-based portfolio optimization,
*Annals of Operations Research*, 245, pp 47-66. - Tural M.K. (2016), Maximal matching polytope in trees,
*Optimization Methods and Software*, 31(3), pp 471-478. - Azizoğlu, M., Çetinkaya F.C., Kırbıyık S. (2015), LP relaxation-based solution algorithms for the multi-mode project scheduling with a non-renewable resource,
*European Journal of Industrial Engineering*, 9(4), pp 450-469. - Çavdar B., Sokol J. (2015), TSP race: Minimizing completion time in time-sensitive applications,
*European Journal of Operational Research*, 244(1), pp 47-54. - Çavdar B., Sokol J. (2015), A distribution-free TSP tour length estimation model for random graphs,
*European Journal of Operational Research*, 243(2), pp 588-598. - Çelik B., Karasakal E., İyigün C. (2015), A probabilistic multiple criteria sorting approach based on distance functions,
*Expert Systems with Applications*, 42(7). - Damgacıoğlu H., Dinler D., Özdemirel N.E., İyigün C. (2015), A genetic algorithm for the uncapacitated single allocation planar hub location problem,
*Computers & Operations Research*, 62, pp 224-236. - Dinler D., Tural M.K., İyigün C. (2015), Heuristics for a continuous multi-facility location problem with demand regions,
*Computers & Operations Research*, 62, pp 237-256. - Duran A.S., Gürel S., Aktürk M.S. (2015), Robust airline scheduling with controllable cruise times and chance constraints,
*IIE Transactions*, 47, pp 64–83. - Farham M.S., Süral H., İyigün C. (2015), The Weber problem in congested regions with entry and exit points,
*Computers & Operations Research*, 62, pp 177-183. - Özmen M., Tunç S., Yağız G., Yıldırım S. , Yıldız E., Köksalan M., Gürel S. (2015), Merkezi vezne yer seçimi ve ATM envanter yönetim politikaları ile nakit yönetim sistemi optimizasyonu,
*Endüstri Mühendisliği Dergisi*, 26(2), pp 4-20. - Avşar Z.M., Zijm W.H. (2014), Approximate queueing models for capacitated multi-stage inventory systems under base-stock control,
*European Journal of Operational Research*, 236(1), pp 135-146. - Çolak E., Azizoğlu M. (2014), A resource investment problem with time/resource trade-offs,
*Journal of Operational Research Society*, 65, pp 621-636. - Dehnokhalaji A, Korhonen P.J., Köksalan M., Nasrabadi N., Öztürk D.T., Wallenius J. (2014), Constructing a strict total order for alternatives characterized by multiple criteria: An extension,
*Naval Research Logistics*, 61(2), pp 155-163. - Güden H., Süral H. (2014), Locating mobile facilities in railway construction management,
*Omega*, 45, pp 71-79. - Lokman B., Köksalan M. (2014), Finding highly preferred points for multi-objective integer programs,
*IIE Transactions*, 46, pp 1181–1195.