Aydin Sipahioglu

• Professor (Full) at Eskişehir Osmangazi University

Milk-run is a cyclic material delivery system, that aims to increase the efficiency of transportation and supply chain considering the lean logistics aspect. There are two types of milk-run systems in the literature: supplier and in-plant milk-run. The in-plant milk-run system, which has attracted increasing attention with the Industry 4.0 concept,...

The drone arc routing problem (DARP) is one of the arc routing problems (ARPs) that has been studied by researchers recently. Unlike traditional ARPs, drones can travel directly between any two points in the graph. Due to the flexibility of drones, it is possible to use edges not defined in the graphs when deadheading the edges. This advantage of d...

Endüstri Mühendisliği insan, makine ve malzemeden oluşan bütünleşik sistemlerin tasarımı, kurulması ve geliştirilmesi ile ilgilenir. Kaynakların verimli kullanımının gittikçe daha önemli olduğu küresel dünyada, tesislerin yer seçimi ve yerleşiminden, hammadde ve diğer girdilerin tedariğine, üretim süreçlerinin planlanması ve çizelgelenmesinden stok...

Many optimization problems are complex, challenging and take a significant amount of computational effort to solve. These problems have attracted the attention of researchers and they have developed lots of metaheuristic algorithms to use for solving these problems. Most of the developed metaheuristic algorithms are based on some metaphors. For thi...

Milk-run, a cyclic material delivering system, aims to increase the efficiency of transportation and supply chain based on lean logistics perspective. There are two kinds of milk-run systems as supplier and in-plant milk-run system in the literature. In-plant milk-run system that has growing appeals with Industry 4.0 concept, is applied to manage t...

One of the most common plastic manufacturing methods is injection molding. In injection molding process, scheduling of plastic injection machines is very difficult because of the complex nature of the problem. For example, similar plastic parts should be produced sequentially to prevent long setup times. On the other hand, to produce a plastic part...

There are many metaheuristic algorithms in the literature. One of some important components that affect the performance of the metaheuristics is constraint handling strategies. The purpose of using these strategies is to reach feasible and high quality solutions in the solution space. Our research aims at exploring the effects of the constraint han...

The milk-run is an in-plant lean logistics application where from a central warehouse; full-boxes of components are supplied to the line-side buffer stock areas of the assembly stations, on a just-in time basis, and in a cyclic manner, so that the stations do not run out of stock [10]. The associated problem is the cyclic Inventory Routing Problem...

Teknolojinin havacilik alaninda sagladigi yenilikler hava sahasinin her gecen gun daha da kalabalik hale gelmesine sebep olmaktadir. Farkli amaclar icin uretilen farkli hava araclari hava sahasinda yerini almaktadir. Bu yuzden hava trafigini yonetmek daha da zor hale gelmektedir. Hava sahasi sektor tasarimi, bir digerdeyisle hava sahasi sorumluluk...

The German OR Society (GOR; https://gor.uni-paderborn. de/) meetings have increasingly been attended by colleagues from abroad, attesting to its lively relations with other national OR societies within and outside of the EURO. GOR has forged partnership agreements with other societies to encourage rich scientific collaboration. In particular, Gerha...

Multirobot sensor-based coverage path planning determines a tour for each robot in a team such that every point in a given workspace is covered by at least one robot using its sensors. In sensor-based coverage of narrow spaces, i.e., obstacles lie within the sensor range, a generalized Voronoi diagram (GVD)-based graph can be used to model the envi...

The Quadratic Knapsack Problem (QKP) is one of the well-known combinatorial optimization problems. If more than one knapsack exists, then the problem is called a Quadratic Multiple Knapsack Problem (QMKP). Recently, knapsack problems with setups have been considered in the literature. In these studies, when an item is assigned to a knapsack, its se...

Cumulative capacitated vehicle routing problem (CCVRP) is an extension of the well-known capacitated vehicle routing problem, where the objective is minimization of sum of the arrival times at nodes instead of minimizing the total tour cost. This type of routing problem arises when a priority is given to customer needs or dispatching vital goods su...

Capacitated arc routing problem (CARP) is the determination of vehicle tours that serve all positive-demand edges (required edge) exactly once without exceeding vehicle capacity while minimizing sum of all tour costs. In CARP, total demand of a tour is calculated by means of all required edges on the tour. In this study, a new CARP variation is int...

Multi-robot sensor-based coverage path planning requires every point given in the workspace has to be covered at least by a sensor of a robot in the robot team. In this study, a novel algorithm was proposed for the sensor-based coverage of narrow environments by considering energy capacities of the robots. For this purpose, the environment was mode...

In this study, a novel dynamic path planning approach is proposed for multi-robot sensor-based coverage considering energy capacities of the mobile robots. The environment is assumed to be narrow and partially unknown. A Generalized Voronoi diagram-based network is used for the sensor-based coverage planning due to narrow nature of the environment....

In this study, a novel sensor-based coverage algorithm is proposed for multi-robots considering energy capacities of the mobile robots. Firstly, the environment is modeled by a Generalized Voronoi diagram-based graph to guarantee complete sensor based coverage. Secondly, depending on required arc set, an initial complete coverage route is created b...

In this study, the performance of the modified subgradient algorithm (MSG) to solve the 0-1 quadratic knapsack problem (QKP) was examined. The MSG was proposed by Gasimov for solving dual problems constructed with respect to sharp Augmented Lagrangian function. The MSG has some important proven properties. For example, it is convergent, and it guar...

Multi-robot systems have recently received a great deal of attention due to the ability to perform an assigned task in a more reliable, faster and cheaper way beyond what is possible with a single robot. However, they may have some drawbacks, such as obstruction among robots during a task. Non-intersecting tours are preferable for the robots to pre...

Mobile robots are increasingly used in many areas. An optimum trajectory increases the effectiveness of a mobile robot. However, the environment may change dynamically which may require a real-time tour construction for the mobile robot.In this study, a heuristic-based TSP approach is applied to real-time dynamic tour construction problem for a mob...

The Quadratic Multiple Knapsack Problem (QMKP) is a generaliz- ation of the quadratic knapsack problem, which is one of the well-known combinatorial optimization problems, from a single knapsack to k knapsacks with (possibly) different capacities. The objective is to assign each item to at most one of the knapsacks such that none of the capacity co...

In this paper we study a 1.5-dimensional cutting stock and assortment problem which includes determination of the number of different widths of roll stocks to be maintained as inventory and determination of how these roll stocks should be cut by choosing the optimal cutting pattern combinations. We propose a new multi-objective mixed integer linear...

In this study, a vehicle routing problem-based approach is presented to construct non-intersecting routes for the members of a mobile robot team. It is assumed that each robot starts from a central location such as the charging point, completes its route and returns to the starting location. The proposed method consists of three algorithms: a sweep...

One of the main concerns in multi-robot applications is the effects of interactions among the robots on the total performance of the team. If the robots are assigned to spatially separate tasks, the negative impact of these interactions may be decreased. In this paper a VRP-based method is proposed to create non-intersecting routes for a team of ro...

The quadratic multiple knapsack problem (QMKP) is a generalization of the quadratic knapsack problem from a single knapsack to k knapsacks. In this study, the mathematical model of the QMKP is generalized as covering the constraints that we may face in real life problems. A new hybrid algorithm which combines F-MSG algorithm and genetic algorithm i...