@article {1542, title = {An Exact Cutting Plane Algorithm to Solve the Selective Graph Coloring Problem in Perfect Graphs}, journal = {European Journal of Operational Research}, volume = {291(1)}, year = {2021}, pages = {67{\textendash}83}, doi = {https://doi.org/10.1016/j.ejor.2020.09.017}, author = {Oylum {\c S}eker and Ekim, Tinaz and Z C Ta{\c s}k{\i}n} } @article {1417, title = {Analysis of an individual-based influenza epidemic model using random forest metamodels and adaptive sequential sampling}, journal = {Systems Research and Behavioral Science}, volume = {37}, year = {2020}, pages = {936-958}, abstract = {

Abstract This study proposes a three-step procedure for the analysis of input{\textendash}response relationships of dynamic models, which enables the analyst to develop a better understanding about the dynamics of the system. The main building block of the procedure is a random forest metamodel capturing the input{\textendash}output relationships. We utilize an active learning approach as the second step to improve the accuracy of the metamodel. In the last step, we develop a novel way to present the information captured by the metamodel as a set of intelligible IF{\textendash}THEN rules. For illustration, we use the FluTE model, which is an individual-based influenza epidemic model. We observe that the number of daily applicable vaccines determines the success of an intervention strategy the most. Another critical observation is that when the daily available vaccines are constrained, nonpharmaceutical strategies should be incorporated to reduce the extent of the outbreak.

}, keywords = {adaptive sequential sampling, FluTE, individual-based modelling, Metamodeling, Rule Extraction}, doi = {https://doi.org/10.1002/sres.2763}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/sres.2763}, author = {Edali, Mert and G{\"o}nen{\c c} Y{\"u}cel} } @article {1498, title = {The complexity of the defensive domination problem in special graph classes}, journal = {Discrete Mathematics}, volume = {343}, year = {2020}, pages = {111665}, abstract = {

A k-attack on a graph G is a set of k distinct vertices {a1,{\textellipsis},ak} which are said to be under attack. A k-attack A can be countered or defended by a subset of defender vertices X if and only if there exists an injective function f from A to X, such that either f(ai)=ai or (ai,f(ai)) is an edge of G, for all i, 1<=i<=k. Given a graph G, a subset D of V is a k-defensive dominating set of G if and only if D can counter any k-attack in G. We consider the k-defensive dominating set problem. We start a systematic study on the complexity of the k-defensive dominating set problem. When k is not fixed, we show that it is already co-NP-hard to decide whether a given set of vertices is a k-defensive dominating set or not. However, if k is fixed, then we show that the problem is NP-complete even in split graphs. Subsequently, we consider special graph classes, namely paths, cycles, co-chain graphs and threshold graphs. We show that in each of these graph classes, a k-defensive dominating set of minimum size can be found in linear time even for non-fixed k.

}, keywords = {Domination, Networks, Security}, issn = {0012-365X}, doi = {https://doi.org/10.1016/j.disc.2019.111665}, url = {https://www.sciencedirect.com/science/article/pii/S0012365X19303437}, author = {Ekim, Tinaz and Arthur M. Farley and Andrzej Proskurowski} } @article {1499, title = {Mind the independence gap}, journal = {Discrete Mathematics}, volume = {343}, year = {2020}, pages = {111943}, abstract = {

The independence gap of a graph was introduced by Ekim et al.\ in 2018 as a measure of how far a graph is from being well-covered. It is defined as the difference between the maximum and minimum size of a maximal independent set. We investigate the independence gap of a graph from structural and algorithmic points of view, with a focus on classes of perfect graphs. Generalizing results on well-covered graphs due to Dean and Zito (1994) and Hujdurovi{\'c} et al.\ (2018), we express the independence gap of a perfect graph in terms of clique partitions and use this characterization to develop a polynomial-time algorithm for recognizing graphs of constant independence gap in any class of perfect graphs of bounded clique number. Next, we introduce a hereditary variant of the parameter, which we call hereditary independence gap and which measures the maximum independence gap over all induced subgraphs of the graph. We show that determining whether a given graph has hereditary independence gap at most k is polynomial-time solvable if k is fixed and co-NP-complete if k is part of input. We also investigate the complexity of the independent set and independent domination problems in graph classes related to independence gap. In particular, we show that the two problems are NP-complete in the class of graphs of independence gap at most one and that the weighted independent set problem is polynomial-time solvable in any class of graphs with bounded hereditary independence gap. Combined with some known results on claw-free graphs, our results imply that the independent domination problem is solvable in polynomial time in the class of {claw, 2P3}-free graphs.

}, keywords = {Hereditary independence gap, Independent dominating set, Maximal independent set, NP-hard problem, Polynomial-time algorithm, Well-covered graph}, issn = {0012-365X}, doi = {https://doi.org/10.1016/j.disc.2020.111943}, url = {https://www.sciencedirect.com/science/article/pii/S0012365X20301321}, author = {Ekim, Tinaz and Didem G{\"o}z{\"u}pek and Ademir Hujdurovi{\'c} and Martin Milani{\v c}} } @article {1586, title = {A robust disaster preparedness model for effective and fair disaster response}, journal = {European Journal of Operational Research}, volume = {280}, year = {2020}, pages = {479{\textendash}494}, doi = {10.1016/j.ejor.2019.07.029}, url = {https://doi.org/10.1016/j.ejor.2019.07.029}, author = {G{\"o}kalp Erbeyo{\u g}lu and {\"U}mit Bilge} } @article {1415, title = {Classification of generic system dynamics model outputs via supervised time series pattern discovery}, journal = {Turkish Journal of Electrical Engineering \& Computer Sciences}, volume = {27}, year = {2019}, pages = {832{\textendash}846}, author = {Edali, Mert and Mustafa Gokce Baydogan and G{\"o}nen{\c c} Y{\"u}cel} } @article {1431, title = {A decomposition approach to solve the selective graph coloring problem in some perfect graph families}, journal = {Networks}, volume = {73}, year = {2019}, pages = {145-169}, abstract = {

Graph coloring is the problem of assigning a minimum number of colors to all vertices of a graph such that no two adjacent vertices receive the same color. The selective graph coloring problem is a generalization of the standard graph coloring problem; given a graph with a partition of its vertex set into clusters, the objective is to choose exactly one vertex per cluster so that, among all possible selections, the number of colors necessary to color the vertices in the selection is minimum. This study focuses on a decomposition based exact solution framework for selective coloring in some perfect graph families: in particular, permutation, generalized split, and chordal graphs where the selective coloring problem is known to be NP-hard. Our method combines integer programming techniques and combinatorial algorithms for the graph classes of interest. We test our method on graphs with different sizes and densities, present computational results and compare them with solving an integer programming formulation of the problem by CPLEX, and a state-of-the art algorithm from the literature. Our computational experiments indicate that our decomposition approach significantly improves solution performance in low-density graphs, and regardless of edge-density in the class of chordal graphs.

}, keywords = {chordal graphs, decomposition algorithm, generalized split graphs, integer programming, partition coloring, permutation graphs, selective graph coloring}, doi = {https://doi.org/10.1002/net.21850}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/net.21850}, author = {{\c S}eker, Oylum and Ekim, Tinaz and Z C Ta{\c s}k{\i}n} } @article {1501, title = {Edge-stable equimatchable graphs}, journal = {Discrete Applied Mathematics}, volume = {261}, year = {2019}, pages = {136-147}, abstract = {

A graph G is equimatchable if every maximal matching of G has the same cardinality. We are interested in equimatchable graphs such that the removal of any edge from the graph preserves the equimatchability. We call an equimatchable graph G edge-stable if G\e, that is the graph obtained by the removal of edge e from G, is also equimatchable for any e∈E(G). After noticing that edge-stable equimatchable graphs are either 2-connected factor-critical or bipartite, we characterize edge-stable equimatchable graphs. This characterization yields an O(min(n3.376,n1.5m)) time recognition algorithm. Lastly, we introduce and shortly discuss the related notions of edge-critical, vertex-stable and vertex-critical equimatchable graphs. In particular, we emphasize the links between our work and the well-studied notion of shedding vertices, and point out some open questions.

}, keywords = {1-well-covered, Edge-criticality, Edge-stability, Maximal matching, Shedding vertex}, issn = {0166-218X}, doi = {https://doi.org/10.1016/j.dam.2018.09.033}, url = {https://www.sciencedirect.com/science/article/pii/S0166218X18305158}, author = {Zakir Deniz and Ekim, Tinaz} } @article {1416, title = {Exploring the behavior space of agent-based simulation models using random forest metamodels and sequential sampling}, journal = {Simulation Modelling Practice and Theory}, volume = {92}, year = {2019}, pages = {62-81}, abstract = {

Agent-based modeling is an effective way of understanding and analyzing complex adaptive phenomena. In this respect, discovering the relationship between inputs and outputs of agent-based models is the ultimate way of providing insights into understanding the dynamics of the system being modeled. Therefore, there are many approaches in the literature to clarify these relationships including sampling and metamodeling. Emphasizing the weaknesses and disadvantages of current methods, we present a metamodel-guided sequential sampling technique which combines random forests and uncertainty sampling. Experimental results on two well-known agent-based models show that the presented technique yields metamodels of higher accuracy compared to metamodels trained with randomly selected input{\textendash}output data. Contrary to the previous studies emphasizing only the improvement in the metamodel accuracy, we also focus on input parameter combinations selected by the sequential sampling technique, and we observe that sequential sampling is able to capture the boundaries of tipping point behaviors as well as the points exhibiting counter-intuitive behavior, thus, potentially aiding verification, validation, and understanding of agent-based models. Additionally, we propose a novel two-step method for the categorization of the agent-based model outputs prior to metamodel training, which helps the analyst to decide on whether preserving numerical model outputs or continuing the metamodel training procedure with qualitative categorical agent-based model outputs.

}, keywords = {Active learning, Agent-based modeling, Metamodeling, Output categorization, Random forest, Sequential sampling}, issn = {1569-190X}, doi = {https://doi.org/10.1016/j.simpat.2018.12.006}, url = {https://www.sciencedirect.com/science/article/pii/S1569190X18301941}, author = {Mert Edali and G{\"o}nen{\c c} Y{\"u}cel} } @article {1445, title = {SLA-aware optimal resource allocation for service-oriented networks}, journal = {Future Generation Computer Systems}, volume = {101}, year = {2019}, pages = {959-974}, abstract = {

The popularity of traditional network services and web content is succeeded by the recent trend in customized services proliferated by the smart devices and gadgets. Fall-risk assessment, augmented reality, ECG (electrocardiography) monitoring, virtual reality-based gaming and similar services are driven through data generated by multi-modal sensors embedded in the end-user equipment. These services may possess varying characteristics and requirements represented with performance metrics and Quality of Service (QoS) parameters. Even though the small form-factor end-user gadgets are getting powerful in terms of resource capacity, they are still incapable of executing complex routines, and thus these tasks should be offloaded to a remote machine. Service-Centric Networks (SCN) focus on delivering customized services to the users in a location-independent fashion. This is in parallel with previous vision put forward by the Information-Centric Networks (ICN) and Content Delivery Networks (CDN), which aim to enhance the end-user experience. The novel set of services for complementing the daily activities of the end-users mostly depicts a latency-intolerant attribute which ultimately calls for a full-fledged resource allocation scheme. Within this context, both computation and networking resources should be allocated optimally, and task assignments should be handled precisely for following the requirements specified by the Service Level Agreements (SLAs). This paper initially presents and discusses problem definitions that should be addressed by the service-centric multi-tier computing architecture that is composed of edge, metro, and cloud servers. In order to achieve this objective, an SLA-aware optimal resource allocation and task assignment model for service-oriented networks is proposed. This optimization model is based on a nonlinear delay formulation for accommodating service-centric network scenarios under various conditions. It is then reshaped as a mixed-integer linear model through piecewise linear approximation. Additionally, a heuristic implementation is presented to address the time and space complexities of the problem for which the aforementioned optimization models remain ineffective. Performance evaluation results show that the proposed solutions are able to find a good allocation of resources while taking the requirements of the services into account.

}, keywords = {Cloud computing, Edge computing, Network optimization, Service-centric networks, Task offloading}, issn = {0167-739X}, doi = {https://doi.org/10.1016/j.future.2019.07.050}, url = {https://www.sciencedirect.com/science/article/pii/S0167739X19306430}, author = {Ahmet Cihat Bakt{\i}r and Bet{\"u}l Ahat and Necati Aras and Atay {\"O}zg{\"o}vde and Cem Ersoy} } @article {1500, title = {Small 1-defective Ramsey numbers in perfect graphs}, journal = {Discrete Optimization}, volume = {34}, year = {2019}, pages = {100548}, abstract = {

In this paper, we initiate the study of defective Ramsey numbers for the class of perfect graphs. Let PG be the class of all perfect graphs and R1PG(i,j) denote the smallest n such that all perfect graphs on n vertices have either a 1-dense i-set or a 1-sparse j-set. We show that R1PG(3,j)=j for any j>=2, R1PG(4,4)=6, R1PG(4,5)=8, R1PG(4,6)=10, R1PG(4,7)=13, R1PG(4,8)=15 and R1PG(5,5)=13. We exhibit all extremal graphs for R1PG(4,7)=13 (there are exactly three). We also obtain the 1-defective Ramsey number of order (4,7) in triangle-free perfect graphs, namely R1ΔPG(4,7)=12.

}, keywords = {-dense, -dependent, -sparse, Extremal graphs}, issn = {1572-5286}, doi = {https://doi.org/10.1016/j.disopt.2019.06.001}, url = {https://www.sciencedirect.com/science/article/pii/S1572528618301622}, author = {Ekim, Tinaz and John Gimbel and Oylum {\c S}eker} } @article {1503, title = {On Almost Well-Covered Graphs of Girth at Least 6}, journal = {Discrete Mathematics \& Theoretical Computer Science}, volume = {20}, year = {2018}, author = {Milani{\v c}, Martin and Hujdurovi{\'c}, Ademir and G{\"o}z{\"u}pek, Didem and Ekim, Tinaz} } @article {1414, title = {Automated Analysis of Regularities Between Model Parameters and Output Using Support Vector Regression in Conjunction with Decision Trees}, journal = {Journal of Artificial Societies and Social Simulation}, volume = {21}, year = {2018}, pages = {1}, abstract = {

Opening the black-box of nonlinear relationships between model inputs and outputs, significantly contributes to the understanding of the dynamic problem being studied. Considering the weaknesses and disadvantages of human-guided and systematic techniques offered in the literature, this paper presents a model analysis and exploration tool for agent-based models. The tool first approximates input-output relationships by developing a metamodel, a simplified representation of the original agent-based model. For this purpose, it utilizes support vector regression, which is capable of approximating highly nonlinear systems accurately. Following metamodel fitting, the tool incorporates a tree-based method to extract knowledge embedded in the metamodel. The resulting tree is then expressed as a set of IF-THEN rules that have high comprehensibility compared to complex metamodel function. We utilized the tool for the exploration of Traffic Basic model and the results show the relationship between model input and output. Furthermore, rules extracted from the metamodel point out certain counter-intuitive results of the model which are not easily inferred from the raw input-output data. We also discuss potential uses of our tool and provide the R script which makes the analysis repeatable for other agent-based models.

}, keywords = {decision tree, MetaModel, R, Rule Extraction, Support Vector Regression, Traffic}, issn = {1460-7425}, doi = {10.18564/jasss.3786}, url = {http://jasss.soc.surrey.ac.uk/21/4/1.html}, author = {Edali, Mert and G{\"o}nen{\c c} Y{\"u}cel} } @article {1509, title = {Equimatchable claw-free graphs}, journal = {Discrete Mathematics}, volume = {341}, year = {2018}, pages = {2859-2871}, abstract = {

A graph is equimatchable if all of its maximal matchings have the same size. A graph is claw-free if it does not have a claw as an induced subgraph. In this paper, we provide the first characterization of claw-free equimatchable graphs by identifying the equimatchable claw-free graph families. This characterization implies an efficient recognition algorithm.

}, keywords = {Connectivity, Equimatchable graph, Factor-critical}, issn = {0012-365X}, doi = {https://doi.org/10.1016/j.disc.2018.06.043}, url = {https://www.sciencedirect.com/science/article/pii/S0012365X18302140}, author = {Saieed Akbari and Hadi Alizadeh and Ekim, Tinaz and Didem G{\"o}z{\"u}pek and Mordechai Shalom} } @article {1504, title = {Graphs of Edge-Intersecting Non-Splitting Paths in a Tree: Representations of Holes-Part II}, journal = {Discrete Mathematics and Theoretical Computer Science}, volume = {20}, year = {2018}, pages = {1b{\textendash}1b}, author = {Boyac{\i}, Arman and Ekim, Tinaz and Shalom, Mordechai and Zaks, Shmuel} } @article {1435, title = {Integer Programming Formulations and Benders Decomposition for the Maximum Induced Matching Problem}, journal = {INFORMS Journal on Computing}, volume = {30}, year = {2018}, pages = {43-56}, abstract = {

We investigate the maximum induced matching problem (MIM), which is the problem of finding an induced matching having the largest cardinality on an undirected graph. The problem is known to be NP-hard for general graphs. We first propose a vertex-based integer programming formulation for MIM, which is more compact compared to an edge-based formulation found in the literature. We also introduce the maximum weight induced matching problem (MWIM), which generalizes MIM so that vertices and edges have weights. We adapt the edge-based formulation to MWIM, and propose a quadratic programming formulation of MWIM based on our vertex-based formulation. We then linearize our quadratic programming formulation, and devise a Benders decomposition algorithm that exploits a special structure of the linearized formulation. We also propose valid inequalities and formulation tightening procedures to improve the efficiency of our approach. Our computational tests on a large suite of randomly generated graphs show that our vertex-based formulation and decomposition approach significantly improve the solvability of MIM and MWIM, especially on dense graphs. The online appendix and data are available at https://doi.org/10.1287/ijoc.2017.0764.

}, doi = {10.1287/ijoc.2017.0764}, url = {https://doi.org/10.1287/ijoc.2017.0764}, author = {Ahat, Bet{\"u}l and Ekim, Tinaz and Z C Ta{\c s}k{\i}n} } @article {1502, title = {The maximum cardinality cut problem in co-bipartite chain graphs}, journal = {Journal of Combinatorial Optimization}, volume = {35}, year = {2018}, month = {Jan}, pages = {250{\textendash}265}, issn = {1382-6905}, author = {Ekim, Tinaz and Boyac{\i}, Arman and Shalom, Mordechai} } @article {1507, title = {Complexity of the Improper Twin Edge Coloring of Graphs}, journal = {Graphs and Combinatorics}, volume = {33}, year = {2017}, pages = {595{\textendash}615}, author = {Abedin, Paniz and Akbari, Saieed and Demange, Marc and Ekim, Tinaz} } @proceedings {1180, title = {Edge extremal Graphs Under Degree and Matching Number Restrictions}, journal = {17th Haifa Workshop on Interdisciplinary Applications of Graphs {\textendash} CRI}, year = {2017}, author = {Ekim, Tinaz} } @proceedings {1182, title = {Ergonomics in design: Safety and user experience factors}, journal = {2nd International Conference on Design and Production Engineering}, year = {2017}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {1159, title = {Influence maximization based on partial network structure information: A comparative analysis on seed selection heuristics}, journal = {International Journal of Modern Physics C}, volume = {28}, year = {2017}, pages = {1750122}, author = {{\c S}irag Erkol and G{\"o}nen{\c c} Y{\"u}cel} } @conference {1185, title = {Linear-Time Generation of Random Chordal Graphs}, booktitle = {International Conference on Algorithms and Complexity}, year = {2017}, publisher = {Springer}, organization = {Springer}, author = {Oylum {\c S}eker and Pinar Heggernes and Ekim, Tinaz and Z. Caner Ta{\c s}k{\i}n} } @article {1508, title = {On matching extendability of lexicographic products}, journal = {RAIRO-Oper. Res.}, volume = {51}, year = {2017}, pages = {857-873}, doi = {10.1051/ro/2016072}, url = {https://doi.org/10.1051/ro/2016072}, author = {Chiarelli, Nina and Dibek, Cemil and Ekim, Tinaz and G{\"o}z{\"u}pek, Didem and Miklavic, Stefko} } @article {1179, title = {Maximum number of edges in claw-free graphs whose maximum degree and matching number are bounded}, journal = {Discrete Mathematics}, volume = {340}, year = {2017}, pages = {927 - 934}, keywords = {Claw-free graphs, Edge-extremal graphs, Maximum matching, Ramsey theory}, issn = {0012-365X}, doi = {https://doi.org/10.1016/j.disc.2017.01.010}, url = {http://www.sciencedirect.com/science/article/pii/S0012365X17300109}, author = {Cemil Dibek and Ekim, Tinaz and Pinar Heggernes} } @article {1158, title = {Musculoskeletal and visual symptoms among undergraduate students: Individual and computer-use-related risk factors and interference with academic performance}, journal = {International Journal of Industrial Ergonomics}, volume = {60}, year = {2017}, pages = {26 - 34}, keywords = {Academic performance, Computer, Musculoskeletal symptom, University student, Visual discomfort}, issn = {0169-8141}, doi = {https://doi.org/10.1016/j.ergon.2015.11.011}, url = {http://www.sciencedirect.com/science/article/pii/S0169814115300573}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {1506, title = {A polynomial-time algorithm for the maximum cardinality cut problem in proper interval graphs}, journal = {Information Processing Letters}, volume = {121}, year = {2017}, pages = {29-33}, abstract = {

It is known that the maximum cardinality cut problem is NP-hard even in chordal graphs. On the positive side, the problem is known to be polynomial time solvable in some subclasses of proper interval graphs which is in turn a subclass of chordal graphs. In this paper, we consider the time complexity of the problem in proper interval graphs, and propose a polynomial-time dynamic programming algorithm.

}, keywords = {Graph algorithms, Maximum cut, Proper interval graph}, issn = {0020-0190}, doi = {https://doi.org/10.1016/j.ipl.2017.01.007}, url = {https://www.sciencedirect.com/science/article/pii/S0020019017300133}, author = {Arman Boyac{\i} and Ekim, Tinaz and Mordechai Shalom} } @proceedings {1183, title = {Recent results on equimatchable graphs}, journal = {Combinatorial Potlatch}, year = {2017}, author = {Ekim, Tinaz} } @article {1505, title = {On two extensions of equimatchable graphs}, journal = {Discrete Optimization}, volume = {26}, year = {2017}, pages = {112-130}, abstract = {

A graph is said to be equimatchable if all its maximal matchings are of the same size. In this work we introduce two extensions of the property of equimatchability by defining two new graph parameters that measure how far a graph is from being equimatchable. The first one, called the matching gap, measures the difference between the sizes of a maximum matching and a minimum maximal matching. The second extension is obtained by introducing the concept of equimatchable sets; a set of vertices in a graph G is said to be equimatchable if all maximal matchings of G saturating the set are of the same size. Noting that G is equimatchable if and only if the empty set is equimatchable, we study the equimatchability defect of the graph, defined as the minimum size of an equimatchable set in it. We develop several inapproximability and parameterized complexity results and algorithms regarding the computation of these two parameters, a characterization of graphs of unit matching gap, exact values of the equimatchability defect of cycles, and sharp bounds for both parameters.

}, keywords = {Edge dominating set, Equimatchable graph, Gallai{\textendash}Edmonds decomposition, Minimum maximal matching, Parameterized complexity}, issn = {1572-5286}, doi = {https://doi.org/10.1016/j.disopt.2017.08.002}, url = {https://www.sciencedirect.com/science/article/pii/S1572528616301438}, author = {Zakir Deniz and Ekim, Tinaz and Tatiana Romina Hartinger and Martin Milani{\v c} and Mordechai Shalom} } @article {1178, title = {Equimatchable graphs are C2k+ 1-free for k>= 4}, journal = {Discrete Mathematics}, volume = {339}, year = {2016}, pages = {2964{\textendash}2969}, author = {Dibek, Cemil and Ekim, Tinaz and G{\"o}z{\"u}pek, Didem and Shalom, Mordechai} } @article {1510, title = {Graphs of edge-intersecting and non-splitting paths}, journal = {Theoretical Computer Science}, volume = {629}, year = {2016}, pages = {40-50}, abstract = {

The families of Edge Intersection Graphs of Paths in a tree (resp. in a grid) EPT (resp. EPG) are well studied graph classes. Recently we introduced the class of graphs of Edge-Intersecting and Non-Splitting Paths in a Tree (ENPT) [5]. In this model, two vertices are adjacent if they represent two intersecting paths of a tree whose union is also a path. In this study we generalize this graph class by allowing the host graph to be an arbitrary graph. These are the graphs of Edge-Intersecting and Non-Splitting Paths ENP. Although the Edge Intersection Graphs of Paths in an arbitrary graph includes all graphs, we show that this is not the case for ENP. We also show that the class ENP coincides with the family of graphs of Edge-Intersecting and Non-Splitting Paths in a Grid (ENPG). Following similar studies for EPG graph class, we study the implications of restricting the number of bends of the individual paths in the grid. We show that such a restriction restricts the graph class. Specifically, by restricting the number of bends one gets an infinite sequence of classes such that every class is properly included in the next one.

}, keywords = {EPG graphs, EPT graphs, Intersection graphs}, issn = {0304-3975}, doi = {https://doi.org/10.1016/j.tcs.2015.10.004}, url = {https://www.sciencedirect.com/science/article/pii/S0304397515008750}, author = {Arman Boyac{\i} and Ekim, Tinaz and Mordechai Shalom and Shmuel Zaks} } @article {1170, title = {Graphs of edge-intersecting non-splitting paths in a tree: Representations of holes{\textemdash}Part I}, journal = {Discrete Applied Mathematics}, volume = {215}, year = {2016}, pages = {47{\textendash}60}, author = {Boyac{\i}, Arman and Ekim, Tinaz and Shalom, Mordechai and Zaks, Shmuel} } @article {1172, title = {On the minimum and maximum selective graph coloring problems in some graph classes}, journal = {Discrete Applied Mathematics}, volume = {204}, year = {2016}, pages = {77{\textendash}89}, author = {Demange, Marc and Ekim, Tinaz and Ries, Bernard} } @article {1194, title = {Optimal Sensor Deployment to Increase the Security of the Maximal Breach Path in Border Surveillance}, year = {2016}, institution = {Bo{\u g}azi{\c c}i University}, author = {Karabulut E and Necati Aras and I. Kuban Altinel} } @article {1177, title = {Prediction equations for permanent impairment of the upper extremity due to the loss of range of motion}, journal = {Work}, volume = {53}, year = {2016}, pages = {409{\textendash}420}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {1169, title = {PSO-based and SA-based metaheuristics for bilinear programming problems: an application to the pooling problem}, journal = {Journal of Heuristics}, volume = {22}, year = {2016}, pages = {147{\textendash}179}, author = {G{\"o}kalp Erbeyo{\u g}lu and {\"U}mit Bilge} } @article {1496, title = {Results of a beer game experiment: Should a manager always behave according to the book?}, journal = {Complexity}, volume = {21}, year = {2016}, pages = {190-199}, abstract = {

We investigate the effect of the literature suggested optimal values of the parameters of a dynamic decision-making heuristic in the presence of semirationally managed supply chain echelons using a soft coded one-to-one version of The Beer Game as an experimental platform. According to the counterintuitive results obtained in this study, it is possible for a {\textquotedblleft}rational manager{\textquotedblright} to obtain higher costs than the costs generated by a {\textquotedblleft}semirational manager.{\textquotedblright} Thus, the results do not support the use of the well-established decision parameter values for the echelon of concern if the other echelons{\textquoteright} inventories are managed suboptimally. {\textcopyright} 2015 Wiley Periodicals, Inc. Complexity 21: 190{\textendash}199, 2016

}, keywords = {anchor-and-adjust heuristic, artificial agents, beer game, stock management, supply chain management}, doi = {https://doi.org/10.1002/cplx.21731}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/cplx.21731}, author = {Edali, Mert and Yasarcan, Hakan} } @article {1512, title = {Advances on defective parameters in graphs}, journal = {Discrete Optimization}, volume = {16}, year = {2015}, pages = {62-69}, abstract = {

We consider the generalization of Ramsey numbers to the defective framework using k-dense and k-sparse sets. We construct the first tableaux for defective Ramsey numbers with exact values whenever it is known, and lower and upper bounds otherwise. In light of defective Ramsey numbers, we consider the defective cocoloring problem which consists of partitioning the vertex set of a given graph into k-sparse and k-dense sets. By the help of efficient graph generation methods, we show that c0(4)=12,c1(3)=12 and c2(2)=10 where ck(m) is the maximum order n such that all n-graphs can be k-defectively cocolored using at most m colors. We also give the numbers of k-defective m-cocritical graphs of order n (until n=10) for different levels of defectiveness and m=2,3 and 4.

}, keywords = {Cocritical graphs, Defective cocoloring, Defective Ramsey numbers, Efficient graph generation}, issn = {1572-5286}, doi = {https://doi.org/10.1016/j.disopt.2015.01.002}, url = {https://www.sciencedirect.com/science/article/pii/S1572528615000031}, author = {Ahu Akdemir and Ekim, Tinaz} } @article {icseri2015estimation, title = {Estimation of digraph costs for keyboard layout optimization}, journal = {International Journal of Industrial Ergonomics}, volume = {48}, year = {2015}, pages = {127{\textendash}138}, publisher = {Elsevier}, author = {{\.I}{\c s}eri, Ali and Mahmut Ek{\c s}io{\u g}lu} } @article {ekcsiouglu2015estimation, title = {An Estimation of Finger-Tapping Rates and Load Capacities and the Effects of Various Factors}, journal = {Human Factors: The Journal of the Human Factors and Ergonomics Society}, year = {2015}, pages = {0018720814563976}, publisher = {SAGE Publications}, author = {Mahmut Ek{\c s}io{\u g}lu and {\.I}{\c s}eri, Ali} } @article {ekcsiouglu2015hand, title = {Hand Torque Strength in Industry: A Critical Review}, journal = {Industrial Engineering Applications in Emerging Countries}, year = {2015}, pages = {81}, publisher = {CRC Press}, author = {Mahmut Ek{\c s}io{\u g}lu} } @proceedings {ekcsiougluinvestigation, title = {An Investigation of User-Experience Design of E-Commerce Websites}, year = {2015}, author = {Mahmut Ek{\c s}io{\u g}lu and Varol, Sevgican and Duman, Yusuf} } @article {1467, title = {Locating recycling facilities for IT based electronic waste in Turkey}, journal = {Journal of Cleaner Production}, volume = {105}, year = {2015}, month = {Oct}, pages = {324{\textendash}336}, issn = {09596526}, author = {Necati Aras and Aybek Korugan and B{\"U}Y{\"U}K{\"O}ZKAN FEYZ{\.I}O{\u G}LU, G{\"U}L{\c C}{\.I}N and S{\.I}VR{\.I}KAYA {\c S}ER{\.I}FO{\u G}LU, FUNDA and Erol, Ismail and Nurtani{\c s} Velio{\u g}lu, Meltem} } @article {ekcsiouglu2015prediction, title = {Prediction equations for permanent impairment of the upper extremity due to the loss of range of motion}, journal = {Journal of WORK}, number = {Preprint}, year = {2015}, pages = {1{\textendash}12}, publisher = {IOS Press}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {1511, title = {On some applications of the selective graph coloring problem}, journal = {European Journal of Operational Research}, volume = {240}, year = {2015}, pages = {307-314}, abstract = {

In this paper we present the Selective Graph Coloring Problem, a generalization of the standard graph coloring problem as well as several of its possible applications. Given a graph with a partition of its vertex set into several clusters, we want to select one vertex per cluster such that the chromatic number of the subgraph induced by the selected vertices is minimum. This problem appeared in the literature under different names for specific models and its complexity has recently been studied for different classes of graphs. Here, we describe different models {\textendash} some already discussed in previous papers and some new ones {\textendash} in very different contexts under a unified framework based on this graph problem. We point out similarities between these models, offering a new approach to solve them, and show some generic situations where the selective graph coloring problem may be used. We focus on specific graph classes motivated by each model, and we briefly discuss the complexity of the selective graph coloring problem in each one of these graph classes and point out interesting future research directions.

}, keywords = {Combinatorial optimization, Computational complexity, Graph theory, partition coloring, Selective coloring}, issn = {0377-2217}, doi = {https://doi.org/10.1016/j.ejor.2014.05.011}, url = {https://www.sciencedirect.com/science/article/pii/S0377221714004184}, author = {Marc Demange and Ekim, Tinaz and Bernard Ries and Cerasela Tanasescu} } @inbook {ekcsiouglu2015turkiye, title = {T{\"u}rkiye{\textquoteright}de {\.I}{\c s} Sa{\u g}l{\i}{\u g}{\i} ve G{\"u}venli{\u g}inin Genel Durumu, {\"O}neriler ve Sistem Yakla{\c s}{\i}m{\i}}, booktitle = {Ge-li-yo-rum Diyen Facia}, year = {2015}, pages = {165{\textendash}181}, publisher = {Bo{\u g}azi{\c c}i {\"U}niversitesi Yay{\i}nlar{\i}}, organization = {Bo{\u g}azi{\c c}i {\"U}niversitesi Yay{\i}nlar{\i}}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {ekim2014block, title = {Block decomposition approach to compute a minimum geodetic set}, journal = {RAIRO-Operations Research}, volume = {48}, number = {04}, year = {2014}, pages = {497{\textendash}507}, publisher = {EDP Sciences}, author = {Ekim, Tinaz and Erey, Aysel} } @conference {edali2014effect, title = {The Effect of Semi-Rational Supply Chain Members on the Decision Parameters Used in Managing the Stock of an Echelon}, booktitle = {The 32nd International System Dynamics Conference, Delft, Netherlands}, year = {2014}, publisher = {System Dynamics Society (http://www.systemdynamics.org/conferences/2014/index.html)}, organization = {System Dynamics Society (http://www.systemdynamics.org/conferences/2014/index.html)}, author = {Edali, Mert and Yasarcan, Hakan} } @article {demange2014efficient, title = {Efficient recognition of equimatchable graphs}, journal = {Information Processing Letters}, volume = {114}, number = {1}, year = {2014}, pages = {66{\textendash}71}, publisher = {Elsevier}, author = {Demange, Marc and Ekim, Tinaz} } @article {1461, title = {Life behavior of shock models for uniformly distributed interarrival times}, journal = {Statistical Papers}, volume = {55}, year = {2014}, month = {Aug}, pages = {841{\textendash}852}, issn = {0932-5026}, author = {ERYILMAZ, SERKAN and K{\"o}n{\"u}l Bayramo{\u g}lu Kavlak} } @article {1497, title = {A Mathematical Model of the Beer Game}, journal = {Journal of Artificial Societies and Social Simulation}, volume = {17}, year = {2014}, pages = {2}, abstract = {

The beer production-distribution game, in short {\textquotedblleft}The Beer Game{\textquotedblright}, is a multiplayer board game, where each individual player acts as an independent agent. The game is widely used in management education aiming to give an experience to the participants about the potential dynamic problems that can be encountered in supply chain management, such as oscillations and amplification of oscillations as one moves from downstream towards upstream echelons. The game is also used in numerous scientific studies. In this paper, we construct a mathematical model that is an exact one-to-one replica of the original board version of The Beer Game. We apply model replication principles and discuss the difficulties we faced in the process of constructing the mathematical model. Accordingly, the model is presented in full precision including necessary assumptions, explanations, and units for all parameters and variables. In addition, the adjustable parameters are stated, the equations governing the artificial agents{\textquoteright} decision making processes are mentioned, and an R code of the model is provided. We also shortly discuss how the R code can be used in experimentation and how it can also be used to create a single-player or multi-player beer game on a computer. Our code can produce the exact same benchmark cost values reported by Sterman (1989) verifying that it is correctly implemented. The mathematical model and the R code presented in this paper aims to facilitate potential future studies based on The Beer Game.

}, keywords = {Acquisition Lag, artificial agents, beer game, Mathematical Model, Replication, System Dynamics}, issn = {1460-7425}, doi = {10.18564/jasss.2555}, url = {http://jasss.soc.surrey.ac.uk/17/4/2.html}, author = {Edali, Mert and Yasarcan, Hakan} } @article {edali2014mathematical, title = {A Mathematical Model of the Beer Game}, journal = {Journal of Artificial Societies and Social Simulation}, volume = {17}, number = {4}, year = {2014}, pages = {jasss{\textendash}soc}, publisher = {Journal of Artificial Societies and Social Simulation}, author = {Edali, Mert and Yasarcan, Hakan} } @article {ekim2014polar, title = {Polar cographs}, journal = {Discrete Applied Mathematics}, volume = {171}, number = {EPFL-ARTICLE-199582}, year = {2014}, pages = {158{\textendash}158}, publisher = {Elsevier Science Bv}, author = {Ekim, Tinaz and Mahadev, NVR and de Werra, Dominique} } @article {ekcsiouglu2014save, title = {Save the Musicians! The Ergonomics of the Drumming}, journal = {Advances in Physical Ergonomics and Human Factors: Part II}, volume = {15}, year = {2014}, pages = {269}, publisher = {AHFE Conference}, author = {Mahmut Ek{\c s}io{\u g}lu and {\"O}zt{\"u}rk, N Kaan and {\c S}irin, Orkun} } @article {keskin2014wireless, title = {Wireless sensor network lifetime maximization by optimal sensor deployment, activity scheduling, data routing and sink mobility}, journal = {Ad Hoc Networks}, volume = {17}, year = {2014}, pages = {18{\textendash}36}, publisher = {Elsevier}, author = {Keskin, M Emre and I. Kuban Altinel and Necati Aras and Ersoy, Cem} } @article {BodurEtAl2013, title = {Decomposition Algorithms for Solving the Minimum Weight Maximal Matching Problem}, journal = {Networks}, volume = {62}, number = {4}, year = {2013}, pages = {273{\textendash}287}, doi = {http://dx.doi.org/10.1002/net.21516}, author = {Merve Bodur and Ekim, Tinaz and Z C Ta{\c s}k{\i}n} } @article {icseri2013finger, title = {Finger tapping rates and the effects of various factors}, journal = {Occupational Safety and Hygiene}, year = {2013}, pages = {31}, publisher = {CRC Press}, author = {{\.I}{\c s}eri, A and Mahmut Ek{\c s}io{\u g}lu} } @article {boyaci2013graphs, title = {Graphs of Edge-Intersecting Non-splitting Paths in a Tree: Towards Hole Representations}, year = {2013}, author = {Boyac{\i}, Arman and Ekim, Tinaz and Shalom, Mordechai and Zaks, Shmuel} } @article {eksioglu2013hand, title = {Hand torque strength of female population of Turkey and the effects of various factors}, journal = {Occupational Safety and Hygiene}, year = {2013}, pages = {37}, publisher = {CRC Press}, author = {Mahmut Ek{\c s}io{\u g}lu and Recep, Z} } @article {demange2013hardness, title = {Hardness and approximation of minimum maximal matchings}, journal = {International Journal of Computer Mathematics}, number = {ahead-of-print}, year = {2013}, pages = {1{\textendash}20}, publisher = {Taylor \& Francis}, author = {Demange, Marc and Ekim, Tinaz and Tanasescu, Cerasela} } @article {bilge2013mathematical, title = {Mathematical models for FMS loading and part type selection with flexible process plans}, journal = {European Journal of Industrial Engineering}, year = {2013}, publisher = {Inderscience}, author = {{\"U}mit Bilge and Albey, Erin{\c c} and Be{\c s}ikci, Umut and Erbatur, Kemalettin and Aslan, Ay{\c s}e Nur} } @mastersthesis {erbeyoglu, title = {Metaheuristic Approaches to the Pooling Problem}, year = {2013}, school = {Bo{\u g}azi{\c c}i University}, type = {MS}, author = {G{\"o}kalp Erbeyo{\u g}lu} } @article {demange2013note, title = {A note on the NP-hardness of two matching problems in induced subgrids}, journal = {Discrete Mathematics and Theoretical Computer Science}, volume = {15}, number = {2}, year = {2013}, pages = {233{\textendash}242}, author = {Demange, Marc and Ekim, Tinaz and others} } @article {bonomo2013perfectness, title = {Perfectness of clustered graphs}, journal = {Discrete Optimization}, volume = {10}, number = {4}, year = {2013}, pages = {296{\textendash}303}, publisher = {Elsevier}, author = {Bonomo, Flavia and Cornaz, Denis and Ekim, Tinaz and Ries, Bernard} } @article {ekim2013polar, title = {Polar permutation graphs are polynomial-time recognisable}, journal = {European Journal of Combinatorics}, volume = {34}, number = {3}, year = {2013}, pages = {576{\textendash}592}, publisher = {Academic Press}, author = {Ekim, Tinaz and Heggernes, Pinar and Meister, Daniel} } @article {ekim2013some, title = {Some Defective Parameters in Graphs}, journal = {Graphs and Combinatorics}, volume = {29}, number = {2}, year = {2013}, pages = {213{\textendash}224}, publisher = {Springer Japan}, author = {Ekim, Tinaz and Gimbel, John} } @conference {icseritapping, title = {Tapping Rates of Fingers and the Effects of Age, Gender and Hand Preference}, booktitle = {SHO2013 {\textendash}International Symposium on Occupational Safety and Hygiene}, year = {2013}, author = {{\.I}{\c s}eri, Ali and Mahmut Ek{\c s}io{\u g}lu} } @inbook {ekcsiouglu2013user, title = {A user experience study of airline websites}, booktitle = {Design, User Experience, and Usability. Web, Mobile, and Product Design}, year = {2013}, pages = {173{\textendash}182}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, author = {Mahmut Ek{\c s}io{\u g}lu and Kiris, Esin and \cCak{\i}r, Tu{\u g}ba and G{\"u}vendik, Merve and Koyut{\"u}rk, Efsane D and Y{\i}lmaz, Merve} } @inbook {ekim2012computing, title = {Computing minimum geodetic sets of proper interval graphs}, booktitle = {LATIN 2012: Theoretical Informatics}, year = {2012}, pages = {279{\textendash}290}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, author = {Ekim, Tinaz and Erey, Aysel and Heggernes, Pinar and van{\textquoteright}t Hof, Pim and Meister, Daniel} } @article {guney2012efficient, title = {Efficient solution techniques for the integrated coverage, sink location and routing problem in wireless sensor networks}, journal = {Computers \& Operations Research}, volume = {39}, number = {7}, year = {2012}, pages = {1530{\textendash}1539}, publisher = {Elsevier}, author = {G{\"u}ney, Evren and Necati Aras and I. Kuban Altinel and Ersoy, Cem} } @article {TaskinEkim2012, title = {Integer Programming Formulations for the Minimum Weighted Maximal Matching Problem}, journal = {Optimization Letters}, volume = {6(6)}, year = {2012}, pages = {1161-1171}, doi = {http://dx.doi.org/10.1007/s11590-011-0351-x}, author = {Z C Ta{\c s}k{\i}n and Ekim, Tinaz} } @article {1465, title = {Residual Lifetime of Consecutive $k$-out-of- $n$ Systems Under Double Monitoring}, journal = {IEEE Transactions on Reliability}, volume = {61}, year = {2012}, pages = {792-797}, doi = {10.1109/TR.2012.2206272}, author = {ERYILMAZ, SERKAN and K{\"o}n{\"u}l Bayramo{\u g}lu Kavlak} } @article {eksioglu2011endurance, title = {Endurance time of grip-force as a function of grip-span, posture and anthropometric variables}, journal = {International Journal of Industrial Ergonomics}, volume = {41}, number = {5}, year = {2011}, pages = {401{\textendash}409}, publisher = {Elsevier}, author = {Mahmut Ek{\c s}io{\u g}lu} } @inbook {ekcsiouglu2011heuristic, title = {Heuristic evaluation and usability testing: case study}, booktitle = {Internationalization, Design and Global Development}, year = {2011}, pages = {143{\textendash}151}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, author = {Mahmut Ek{\c s}io{\u g}lu and Kiris, Esin and \cCapar, Burak and Sel{\c c}uk, Murat N and Ouzeir, Selen} } @article {keskin2011lifetime, title = {Lifetime maximization in wireless sensor networks using a mobile sink with nonzero traveling time}, journal = {The Computer Journal}, year = {2011}, pages = {bxr048}, publisher = {Oxford University Press}, author = {Keskin, M Emre and I. Kuban Altinel and Necati Aras and Ersoy, Cem} } @conference {ekcsiouglusystems, title = {Systems-Based Approach to Safety and Health in the Small to Medium-sized Enterprises}, booktitle = {Proceedings of XIX World Congress on Safety and Health at Work}, year = {2011}, pages = {22{\textendash}23}, publisher = {http://app.csgb.gov.tr/isgum/safety2011turkey/kongresunumlaring.html}, organization = {http://app.csgb.gov.tr/isgum/safety2011turkey/kongresunumlaring.html}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {ekcsiouglu2011work, title = {Work-Related Musculoskeletal Disorders and Ergonomics}, journal = {Architect and Engineer}, number = {61}, year = {2011}, pages = {56{\textendash}59}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {13998331, title = {{A column generation based heuristic for sensor placement, activity scheduling and data routing in wireless sensor networks}}, journal = {European Journal of Operational Research}, volume = {207}, year = {2010}, pages = {1014{\textendash}1026}, doi = {10.1016/j.ejor.2010.05.020}, author = {Yavuz Boga{\c c} T{\"u}rkogullari and Necati Aras and I. Kuban Altinel and Cem Ersoy} } @article {13288019, title = {{An efficient heuristic for placement, scheduling and routing in wireless sensor networks}}, journal = {Ad Hoc Networks}, volume = {8}, year = {2010}, pages = {654{\textendash}667}, doi = {10.1016/j.adhoc.2010.01.005}, author = {Yavuz Boga{\c c} T{\"u}rkogullari and Necati Aras and I. Kuban Altinel and Cem Ersoy} } @article {13988334, title = {{Efficient integer programming formulations for optimum sink location and routing in heterogeneous wireless sensor networks}}, journal = {Computer Networks}, volume = {54}, year = {2010}, pages = {1805{\textendash}1822}, doi = {10.1016/j.comnet.2010.02.009}, author = {Evren G{\"u}ney and Necati Aras and I. Kuban Altinel and Cem Ersoy} } @article {erol2010exploring, title = {Exploring reverse supply chain management practices in Turkey}, journal = {Supply Chain Management: An International Journal}, volume = {15}, number = {1}, year = {2010}, pages = {43{\textendash}54}, publisher = {Emerald Group Publishing Limited}, author = {Erol, Ismail and Velioglu, Meltem Nurtanis and Serifoglu, Funda Sivrikaya and B{\"u}y{\"u}k{\"o}zkan, G{\"u}l{\c c}in and Necati Aras and Cakar, Nigar Demircan and Aybek Korugan} } @article {turkougullari2010optimal, title = {Optimal placement, scheduling, and routing to maximize lifetime in sensor networks}, journal = {Journal of the Operational Research Society}, volume = {61}, number = {6}, year = {2010}, pages = {1000{\textendash}1012}, publisher = {Nature Publishing Group}, author = {T{\"u}rko{\u g}ullar{\i}, YB and Necati Aras and I. Kuban Altinel and Ersoy, Cem} } @article {ekim2010recognizing, title = {Recognizing line-polar bipartite graphs in time O (n)}, journal = {Discrete Applied Mathematics}, volume = {158}, number = {15}, year = {2010}, pages = {1593{\textendash}1598}, publisher = {Elsevier}, author = {Ekim, Tinaz and Huang, Jing} } @article {ekim2010split, title = {Split-critical and uniquely split-colorable graphs}, journal = {Discrete Mathematics and Theoretical Computer Science}, volume = {12}, number = {5}, year = {2010}, pages = {1{\textendash}24}, author = {Ekim, Tinaz and Ries, Bernard and de Werra, Dominique and others} } @book {13282841, title = {{A Tabu Search Heuristic for Point Coverage, Sink Location, and Data Routing in Wireless Sensor Networks}}, series = {EvoWorkshops}, year = {2010}, pages = {83{\textendash}94}, doi = {10.1007/978-3-642-12139-5_8}, author = {Evren G{\"u}ney and I. Kuban Altinel and Necati Aras and Cem Ersoy} } @article {ekcsiouglu2009iyi, title = {{\.I}yi Ergonomi {\.I}yi Ekonomidir}, journal = {End{\"u}stri {\.I}{\c s}letme M{\"u}hendisli{\u g}i Meslek Dal{\i} Ana Komisyonu B{\"u}lteni}, number = {129}, year = {2009}, pages = {22{\textendash}25}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {ekim2009partitioning, title = {Partitioning graphs into complete and empty graphs}, journal = {Discrete Mathematics}, volume = {309}, number = {19}, year = {2009}, pages = {5849{\textendash}5856}, publisher = {Elsevier}, author = {Ekim, Tinaz and Gimbel, John} } @booklet {erdincc2009student, title = {Student Specific Cornell Musculoskeletal Discomfort Questionnaires (SS-CMDQ) (Turkish)}, journal = {http://ergo.human.cornell.edu/ahSSCMDQquestTurkish.html}, year = {2009}, author = {Erdin{\c c}, O{\u g}uzhan and Mahmut Ek{\c s}io{\u g}lu} } @booklet {erdincc2009student, title = {Student Specific Cornell Musculoskeletal Discomfort Questionnaires (SS-CMDQ) (English)}, journal = {http://ergo.human.cornell.edu/ahSSCMDQquest.html}, year = {2009}, author = {Erdin{\c c}, O{\u g}uzhan and Mahmut Ek{\c s}io{\u g}lu} } @article {demange2009tutorial, title = {A tutorial on the use of graph coloring for some problems in robotics}, journal = {European Journal of Operational Research}, volume = {192}, number = {1}, year = {2009}, pages = {41{\textendash}55}, publisher = {North-Holland}, author = {Demange, Marc and Ekim, Tinaz and de Werra, Dominique} } @conference {50780509, title = {{A Variable Neighborhood Search Heuristic for Point Coverage, Sink Location and Data Routing in Wireless Sensor Networks}}, booktitle = {International Conference on Communication Theory, Reliability, and Quality of Service}, year = {2009}, doi = {10.1109/CTRQ.2009.33}, author = {Evren G{\"u}ney and I. Kuban Altinel and Necati Aras and Cem Ersoy} } @article {cherng2009vibration, title = {Vibration reduction of pneumatic percussive rivet tools: mechanical and ergonomic re-design approaches}, journal = {Applied ergonomics}, volume = {40}, number = {2}, year = {2009}, pages = {256{\textendash}266}, publisher = {Elsevier}, author = {Cherng, John G and Mahmut Ek{\c s}io{\u g}lu and K{\i}z{\i}laslan, Kemal} } @article {4363814, title = {{Binary integer programming formulation and heuristics for differentiated coverage in heterogeneous sensor networks}}, journal = {Computer Networks}, volume = {52}, year = {2008}, pages = {2419{\textendash}2431}, doi = {10.1016/j.comnet.2008.05.002}, author = {I. Kuban Altinel and Necati Aras and Evren G{\"u}ney and Cem Ersoy} } @article {geinoz2008construction, title = {Construction of balanced sports schedules using partitions into subleagues}, journal = {Operations Research Letters}, volume = {36}, number = {3}, year = {2008}, pages = {279{\textendash}282}, publisher = {North-Holland}, author = {Geinoz, A and Ekim, Tinaz and de Werra, Dominique} } @proceedings {nisa4, title = {A Dynamic Simulation Model of Academic Publications and Citations}, journal = {26th International Conference of the System Dynamics Society}, year = {2008}, author = {K{\"u}{\c c}{\"u}k, B. and Nisa {\"O}nsel and B. Eskici} } @conference {50713928, title = {{An efficient heuristic for placement, scheduling and routing in wireless sensor networks}}, booktitle = {International Symposium on Computer and Information Sciences}, year = {2008}, doi = {10.1109/ISCIS.2008.4717856}, author = {Yavuz Boga{\c c} T{\"u}rkogullari and Necati Aras and I. Kuban Altinel and Cem Ersoy} } @conference {guney2008efficient, title = {Efficient integer programming formulations for optimum sink location and routing in wireless sensor networks}, booktitle = {Computer and Information Sciences, 2008. ISCIS{\textquoteright}08. 23rd International Symposium on}, year = {2008}, pages = {1{\textendash}6}, publisher = {IEEE}, organization = {IEEE}, author = {Guney, E and I. Kuban Altinel and Necati Aras and Ersoy, Cem} } @conference {ekcsiouglu2008isometric, title = {Isometric grip strength distribution of a Turkish sample}, booktitle = {Proceedings of the XX Annual International Occupational Ergonomics and Safety Conference}, year = {2008}, pages = {20{\textendash}24}, publisher = {International Society of Occupational Ergonomics and Safety ISBN \# 97809654506-4-5}, organization = {International Society of Occupational Ergonomics and Safety ISBN \# 97809654506-4-5}, author = {Mahmut Ek{\c s}io{\u g}lu and Silahl{\i}, Baykar} } @article {demange2008minimum, title = {Minimum maximal matching is NP-hard in regular bipartite graphs}, journal = {Theory and Applications of Models of Computation}, year = {2008}, pages = {364{\textendash}374}, publisher = {Springer}, author = {Demange, Marc and Ekim, Tinaz} } @article {ekim2008polar, title = {Polar cographs}, journal = {Discrete Applied Mathematics}, volume = {156}, number = {10}, year = {2008}, pages = {1652{\textendash}1660}, publisher = {North-Holland}, author = {Ekim, Tinaz and Mahadev, Nadimpalli VR and de Werra, Dominique} } @article {ekim2008polarity, title = {Polarity of chordal graphs}, journal = {Discrete Applied Mathematics}, volume = {156}, number = {13}, year = {2008}, pages = {2469{\textendash}2479}, publisher = {Elsevier}, author = {Ekim, Tinaz and Hell, Pavol and Stacho, Juraj and de Werra, Dominique} } @article {eksioglu2008steering, title = {Steering-wheel grip force characteristics of drivers as a function of gender, speed, and road condition}, journal = {International journal of industrial ergonomics}, volume = {38}, number = {3}, year = {2008}, pages = {354{\textendash}361}, publisher = {Elsevier}, author = {Mahmut Ek{\c s}io{\u g}lu and K{\i}z{\i}laslan, Kemal} } @conference {ekcsiouglu2007automobile, title = {Automobile drivers{\textquoteright} steering force characteristics}, booktitle = {Proceedings of 37th International Conference on Computers and Industrial Engineering}, number = {590-594}, year = {2007}, author = {Mahmut Ek{\c s}io{\u g}lu and K{\i}z{\i}laslan, Kemaal} } @conference {50632893, title = {{Optimal placement and activity scheduling to maximize coverage lifetime in wireless sensor networks}}, booktitle = {International Symposium on Computer and Information Sciences}, year = {2007}, doi = {10.1109/ISCIS.2007.4456874}, author = {Yavuz Boga{\c c} T{\"u}rkogullari and Necati Aras and I. Kuban Altinel and Cem Ersoy} } @article {demange2006approximation, title = {On the approximation of Min Split-coloring and Min Cocoloring.}, journal = {J. Graph Algorithms Appl.}, volume = {10}, number = {2}, year = {2006}, pages = {297{\textendash}315}, author = {Demange, Marc and Ekim, Tinaz and de Werra, Dominique and others} } @article {de2006construction, title = {Construction of sports schedules with multiple venues}, journal = {Discrete Applied Mathematics}, volume = {154}, number = {1}, year = {2006}, pages = {47{\textendash}58}, publisher = {North-Holland}, author = {de Werra, Dominique and Ekim, Tinaz and Raess, C} } @article {50507263, title = {{Effective coverage in sensor networks: Binary integer programming formulations and heuristics}}, volume = {9}, year = {2006}, pages = {4014{\textendash}4019}, doi = {10.1109/ICC.2006.255709}, author = {I. Kuban Altinel and Necati Aras and Evren G{\"u}ney and Cem Ersoy} } @proceedings {kizilaslaneffects, title = {EFFECTS OF FREQUENCY, GRIP FORCE, AND GENDER ON THE PERCEPTION OF STEERING WHEEL LONGITUDINAL VIBRATION}, year = {2006}, author = {K{\i}z{\i}laslan, Kemal and Mahmut Ek{\c s}io{\u g}lu and Amman, Scott A} } @article {bilge2006multi, title = {Multi-attribute responsive dispatching strategies for automated guided vehicles}, journal = {International Journal of Production Economics}, volume = {100}, number = {1}, year = {2006}, pages = {65{\textendash}75}, publisher = {Elsevier}, author = {{\"U}mit Bilge and Esenduran, G{\"o}k{\c c}e and Varol, Nebibe and {\"O}zt{\"u}rk, Zeynep and Ayd{\i}n, Burcu and Alp, Aysun} } @article {eksioglu2006optimal, title = {Optimal work{\textendash}rest cycles for an isometric intermittent gripping task as a function of force, posture and grip span}, journal = {Ergonomics}, volume = {49}, number = {2}, year = {2006}, pages = {180{\textendash}201}, publisher = {Taylor \& Francis}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {ekim2006split, title = {On split-coloring problems (vol 10, pg 211, 2005)}, journal = {JOURNAL OF COMBINATORIAL OPTIMIZATION}, volume = {11}, number = {1}, year = {2006}, pages = {125{\textendash}125}, publisher = {SPRINGER VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, author = {Ekim, Tinaz and de Werra, Dominique} } @conference {ekcsiouglu2005ergonomic, title = {Ergonomic Evaluation Of OCS Audit Station}, booktitle = {Proceedings of XIX Annual International Occupational Ergonomics and Safety Conference (CD-ROM)}, year = {2005}, pages = {403{\textendash}409}, author = {Mahmut Ek{\c s}io{\u g}lu and Lammers, E and Dye, S and Raftery, R} } @article {1482, title = {Modeling Technology Adoption as an Irreversible Investment under Uncertainty the Case of the Turkish Electricity Supply Industry}, journal = {Energy Economics}, volume = {27}, year = {2005}, month = {Jan}, pages = {139{\textendash}163}, author = {Madlener, Reinhard and G{\"u}rkan Kumbaro{\u g}lu and ED{\.I}GER, {\c S}EVKET VOLKAN} } @article {demange2005p, title = {(p, k)-coloring problems in line graphs}, journal = {Theoretical computer science}, volume = {349}, number = {3}, year = {2005}, pages = {462{\textendash}474}, publisher = {Elsevier}, author = {Demange, Marc and Ekim, Tinaz and de Werra, Dominique} } @article {demange2005partitioning, title = {Partitioning cographs into cliques and stable sets}, journal = {Discrete Optimization}, volume = {2}, number = {2}, year = {2005}, pages = {145{\textendash}153}, publisher = {Elsevier}, author = {Demange, Marc and Ekim, Tinaz and de Werra, Dominique} } @article {ekim2005split, title = {On split-coloring problems}, journal = {Journal of Combinatorial Optimization}, volume = {10}, number = {3}, year = {2005}, pages = {211{\textendash}225}, publisher = {Kluwer Academic Publishers}, author = {Ekim, Tinaz and de Werra, Dominique} } @conference {gursoy2005tekstil, title = {Tekstil End{\"u}strisinde bir {\.I}{\c s} {\.I}stasyonunun Ergonomik Analizi: Remay{\"o}z Makinesi}, booktitle = {11. Ulusal Ergonomi Kongresi}, year = {2005}, author = {G{\"u}rsoy, Selin and Erhan, G{\"o}n{\"u}lta{\c s} and Mahmut Ek{\c s}io{\u g}lu} } @article {ekggouglu11uygulanan, title = {Uygulanan Kuvvet, Elkavrama Aral{\i}{\u g}{\i} ve Omuz Duru{\c s}unun Maksimal Kabul Edilebilir {\.I}zometrik ve Kesikli El Kontraksiyon Frekans{\i}na Etkileri}, journal = {11. Ulusal Ergonomi Kongresi}, year = {2005}, pages = {67}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {eksioglu20042, title = {A 2-D Biomechanical Analysis of Microgravity Induced Neutral Body Posture in one-g Environment}, journal = {IIE Annual Conference. Proceedings}, year = {2004}, pages = {1}, publisher = {Institute of Industrial Engineers-Publisher}, author = {Mahmut Ek{\c s}io{\u g}lu and K{\i}z{\i}laslan, Kemal} } @conference {ekcsiouglu20042, title = {A 2-D biomechanical analysis of zero-gravity neutral posture in one-g environment}, booktitle = {Proceedings of 13th IIE Annual Conference (CD- ROM)}, year = {2004}, author = {Mahmut Ek{\c s}io{\u g}lu and K{\i}z{\i}laslan, Kemal} } @article {ekim2004approximation, title = {Approximation preserving reductions for set covering, vertex covering and independent set hierarchies under differential approximationa}, journal = {International Journal of Computer Mathematics}, volume = {81}, number = {5}, year = {2004}, pages = {569{\textendash}582}, publisher = {Taylor \& Francis Group}, author = {Ekim, Tinaz and Paschos, Vangelis Th} } @article {56229753, title = {{Product-line selection and pricing with remanufacturing under availability constraints}}, volume = {5583}, year = {2004}, pages = {244{\textendash}255}, doi = {10.1117/12.572218}, author = {Necati Aras and G{\"o}k{\c c}e Esenduran and I. Kuban Altinel} } @article {eksioglu2004relative, title = {Relative optimum grip span as a function of hand anthropometry}, journal = {International Journal of Industrial Ergonomics}, volume = {34}, number = {1}, year = {2004}, pages = {1{\textendash}12}, publisher = {Elsevier}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {eksioglu2003minimizing, title = {Minimizing $\alpha$ and $\beta$ Errors in Detection Tasks}, journal = {IIE Annual Conference. Proceedings}, year = {2003}, pages = {1}, publisher = {Institute of Industrial Engineers-Publisher}, author = {Mahmut Ek{\c s}io{\u g}lu and Chen, Guangming} } @conference {ekcsiouglu2003minimizing, title = {Minimizing $\alpha$ and $\beta$ errors in detection tasks}, booktitle = {Proceedings of 12th Annual Industrial Engineering Research Conference (CD-ROM)}, year = {2003}, author = {Mahmut Ek{\c s}io{\u g}lu and Chen, G} } @conference {zhuang2001ergonomic, title = {Ergonomic evaluation of a prototype assistive device for moving residents up in bed}, booktitle = {Proceedings of the 6th Annual International Conference on Industrial Engineering-Theory, Applications and Practice (CD-ROM)}, year = {2001}, author = {Zhuang, Ziqing and Mahmut Ek{\c s}io{\u g}lu} } @conference {ekcsiouglu2001model, title = {A model for impairment evaluation of the wrist due to the loss of wrist range of motion}, booktitle = {Proceedings of the 6th Annual International Conference on Industrial Engineering{\textendash}Theory, Applications, and Practice (CD-ROM)}, year = {2001}, author = {Mahmut Ek{\c s}io{\u g}lu and Fernandez, Jeffrey E} } @conference {eksioglu2000effects, title = {Effects of grip span and shoulder posture on endurance limit of force}, booktitle = {IEA 2000/HFES 2000: 14thTriennial Congress}, year = {2000}, author = {Mahmut Ek{\c s}io{\u g}lu} } @conference {eksioglu1999search, title = {In search of relative optimum grip span}, booktitle = {CD-ROM Proceedings of CybErg 1999: The Second International Cyberspace Conference on Ergonomics}, year = {1999}, pages = {494{\textendash}504}, publisher = {The International Ergonomics Association Press}, organization = {The International Ergonomics Association Press}, author = {Mahmut Ek{\c s}io{\u g}lu} } @article {eksioglu1997predicting, title = {Predicting peak pinch strength: Artificial neural networks vs. regression}, journal = {Occupational Health and Industrial Medicine}, volume = {1}, number = {36}, year = {1997}, pages = {5}, author = {Mahmut Ek{\c s}io{\u g}lu and Fernandez, JE and Twomey, JM} } @article {islam1997tabu, title = {A Tabu Search Approach for the Single Machine Mean Tardiness Problem}, journal = {Journal of the Operational Research Society}, volume = {48}, number = {7}, year = {1997}, pages = {751{\textendash}755}, publisher = {Operational Research Society}, author = {Islam, Anvarul and Mahmut Ek{\c s}io{\u g}lu} } @conference {eksioglu1996artificial, title = {Artificial neural network-based prediction models for determiing maximum acceptable frequency of a drilling task}, booktitle = {Advances in Applied Ergonomics (1st International Conference on Applied Ergonomics)}, year = {1996}, pages = {646{\textendash}649}, publisher = {USA Publishing}, organization = {USA Publishing}, author = {Mahmut Ek{\c s}io{\u g}lu and Fernandez, Jeffrey E.} } @book {eksioglu1996determining, title = {Determining the optimum grip span and modeling work/rest cycles for intermittent gripping tasks}, year = {1996}, author = {Mahmut Ek{\c s}io{\u g}lu} } @conference {islam1996optimal, title = {Optimal maintenance inspection frequency: A multicriteria approach}, booktitle = {Proceedings of 5th Industrial Engineering Research Conference}, year = {1996}, pages = {639{\textendash}644}, publisher = {GA: Institute of Industrial Engineers}, organization = {GA: Institute of Industrial Engineers}, author = {Islam, Anvarul and Mahmut Ek{\c s}io{\u g}lu} } @article {eksioglu1996predicting, title = {Predicting peak pinch strength: artificial neural networks vs. regression}, journal = {International Journal of Industrial Ergonomics}, volume = {18}, number = {5}, year = {1996}, pages = {431{\textendash}441}, publisher = {Elsevier}, author = {Mahmut Ek{\c s}io{\u g}lu and Fernandez, Jeffrey E and Twomey, Janet M} } @conference {ekcsiouglu1995artificial, title = {An artificial neural network (ANN)}, booktitle = {Advances in Industrial Ergonomics and Safety VII (Proceedings of the Tenth Annual International Industrial Ergonomics and Safety Conference)}, year = {1995}, pages = {577{\textendash}584}, publisher = {Taylor \& Francis}, organization = {Taylor \& Francis}, author = {Mahmut Ek{\c s}io{\u g}lu and Fernandez, Jeffrey E and Twomey, Janet M} } @book {eksioglu1992model, title = {A Model for Impairment Evaluation of Wrist Due to the Loss of Wrist Range of Motion}, year = {1992}, publisher = {Wichita State University, Department of Industrial Engineering}, organization = {Wichita State University, Department of Industrial Engineering}, author = {Mahmut Ek{\c s}io{\u g}lu} }