Hakan Gultekin

Hakan Gultekin
Sultan Qaboos University | SQU · Department of Mechanical and Industrial Engineering

Assoc. Prof.

About

44
Publications
11,697
Reads
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711
Citations
Citations since 2017
22 Research Items
464 Citations
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
Introduction
Hakan Gultekin currently works at the Department of Mechanical and Industrial Engineering, Sultan Qaboos University. Hakan does research in the area of optimization that includes modeling and solution of Nonlinear/Linear integer programming problems. Developing exact and heuristic solution algorithms for the problems arising in the areas of manufacturing, smart grids, 3D location problems, transportation and logistics, wireless sensor networks.
Additional affiliations
September 2018 - present
Sultan Qaboos University
Position
  • Professor (Associate)
September 2014 - December 2020
TOBB University of Economics and Technology
Position
  • Professor (Associate)
May 2014 - August 2014
TOBB University of Economics and Technology
Position
  • END 424 Quantitative Decision Making Methods
Education
January 2007 - November 2007
University of Liège
Field of study
  • Operations Research
September 2002 - January 2007
Bilkent University
Field of study
  • İndustrial Engineering
September 2000 - September 2002
Bilkent University
Field of study
  • İndustrial Engineering

Publications

Publications (44)
Article
Frequent metering of electricity consumption is crucial for demand-side management in smart grids. However, metered data can be processed fairly easily by employing well-established nonintrusive appliance load monitoring techniques to infer appliance usage, which reveals information about consumers’ private lives. Existing load shaping techniques f...
Preprint
Full-text available
The drone delivery problem (DDP) has been introduced to include aerial vehicles in last-mile delivery operations to increase efficiency. However, the existing studies have not incorporated the communication quality requirements of such a delivery operation. This study introduces the Communication-aware DDP (C-DDP), which incorporates handover and o...
Preprint
Frequent metering of consumption data is crucial for demand side management in smart grids. However, the metered data can easily be processed with nonintrusive appliance load monitoring techniques to infer appliance usage, which provides insight about the private lives of consumers. Existing load shaping techniques for privacy focus only on hiding...
Article
This study considers a flowshop type production system consisting of m machines. A material handling robot transports the parts between the machines and loads and unloads the machines. We consider the sequencing of the robot moves and determining the speeds of these moves simultaneously. These decisions affect both the robot’s energy consumption an...
Article
Full-text available
In smart electricity grids, high time granu-larity (HTG) power consumption data can be decomposed into individual appliance load signatures via Nonintrusive Appliance Load Monitoring techniques to expose appliance usage profiles. Various methods ranging from load shaping to noise addition and data aggregation have been proposed to mitigate this pro...
Article
We address a dynamic covering location problem of an unmanned aerial vehicle base station (UAV-BS), in which the location sequence of a single UAV-BS in a wireless communication network is determined to satisfy data demand arising from ground users. This problem is especially relevant in the context of smart grid and disaster relief. The vertical m...
Preprint
Full-text available
We address a dynamic covering location problem of an Unmanned Aerial Vehicle Base Station (UAV-BS), where the location sequence of a single UAV-BS in a wireless communication network is determined to satisfy data demand arising from ground users. This problem is especially relevant in the context of smart grid and disaster relief. The vertical move...
Article
This paper introduces the airport shuttle bus scheduling problem (ASBSP) as a new practical scheduling variant. In this problem, a number of identical vehicles that have a specific number of available seats provides transfer service between the airport and the city centre. After making a transfer in one direction, the vehicle can either make a new...
Article
The increased use of renewable generators and their intermittent behavior motivates network operators to deploy energy storage systems. In this study, energy storage types, locations, and capacities are optimized for a capacitated electric power network with renewable generation. Short term operational decisions that include charging/discharging sc...
Article
Full-text available
Unmanned Aerial Vehicle Base Stations (UAV-BSs) are envisioned to be an integral component of the next generation Wireless Communications Networks (WCNs) with a potential to create opportunities for enhancing the capacity of the network by dynamically moving the supply towards the demand while facilitating the services that cannot be provided via o...
Article
Full-text available
This study presents a privacy-aware stochas-tic multi-objective optimization framework that considers the objectives of both consumers and utility companies (UCs) in a demand response (DR) scheme. This framework enables a fair optimization of all the objectives together, and can be used to observe their effects on one another. Using this framework,...
Preprint
Full-text available
In smart electricity grids, High Time-Granularity (HTG) electricity usage data can be decomposed into individual appliance load signatures via Non-Intrusive Appliance Load Monitoring (NIALM) techniques , which can be exploited to expose appliance usage profiles. Various methods ranging from load shaping to noise addition and data aggregation have b...
Preprint
Unmanned Aerial Vehicle Base Stations (UAVBSs) are envisioned to be an integral component of the next generation Wireless Communications Networks (WCNs) with a potential to create opportunities for enhancing the capacity of the network by dynamically moving the supply towards the demand while facilitating the services that cannot be provided via ot...
Article
In cyclic scheduling of material handling robots in manufacturing cells, a common approach is to minimize the cycle time objective, which is a measure of the throughput of the cell. In a typical robot move cycle, robot move times constitute a significant portion of the cycle time. During handling operations, robots consume significant amount of ene...
Article
In this study, we consider the 3D location problem of multiple Drone Base Stations (DBSs) together with the allocation of the resources to serve the users in a wireless communication network. The problem is formulated as a dynamic capacitated single-source location-allocation problem. The capacity of a DBS is a non-linear function of the distance a...
Conference Paper
Full-text available
Unmanned aerial vehicles mounted base stations (UAV-BSs) are expected to become one of the significant components of the Next Generation Wireless Networks (NGWNs). Rapid deployment, mobility, higher chances of unobstructed propagation path, and flexibility features of UAV-BSs have attracted significant attention. Despite, potentially, high gains br...
Preprint
Unmanned aerial vehicles mounted base stations (UAV-BSs) are expected to become one of the significant components of the Next Generation Wireless Networks (NGWNs). Rapid deployment, mobility, higher chances of unobstructed propagation path, and flexibility features of UAV-BSs have attracted significant attention. Despite, potentially, high gains br...
Preprint
Addressing the Quality-of-Service (QoS) requirements of users is crucial for service providers to improve the network performance. Furthermore, the transformation from the network-centric to user-centric service paradigm requires service providers to focus on improving the Quality-of-Experience (QoE) which is expected to become an important objecti...
Article
Full-text available
We consider a robotic cell served by a dual-gripper robot that consists of identical CNC machines placed linearly and a material handling robot loading/unloading the machines and transporting the parts between them. Identical parts are to be processed in this system and the CNC machines are capable of performing all the operations that a part requi...
Article
Full-text available
A key enabler for the smart grid is the fine grained monitoring of power utilization. Although such a mechanism is helpful in the optimization of the whole electricity generation, distribution, and consumption cycle, it also creates opportunities for the potential adversaries in deducing the activities and habits of the subscribers. In fact, by uti...
Article
We consider a flow shop type manufacturing cell consisting of m machines and a material handling robot producing multiple parts. The robot transfers the parts between the machines and loads/unloads the machines. We consider the cyclic scheduling of the parts and the robot moves with the objective of maximizing the throughput rate. We develop a mixe...
Article
We focus on an assembly line design problem of a fully automated robotic spot-welding line. Different from existing studies, we take the prescheduled unavailability periods, such as lunch and tea breaks, into account in order to reflect a more realistic production environment. This problem includes allocating operations to the stations and satisfyi...
Article
Full-text available
This study considers a production cell consisting of two machines and a material handling robot. The robot has a buffer space that moves with it. Identical parts are to be produced repetitively in this flowshop environment. The problem is to determine the cyclic schedule of the robot moves that maximizes the throughput rate. After developing the ne...
Article
Full-text available
In a typical Wireless Sensor Network (WSN) application, the basic communication service is the transportation of the data collected from sensors to the base station. For prolonging the network lifetime, energy efficiency should be one of the primary attributes of such a service. The amount of data transmitted by a node usually depends on how much l...
Article
This study considers the throughput optimization in a two-machine flowshop producing identical jobs. Unlike the general trend in the scheduling literature, the machines are assumed to be capable of performing different operations. As a consequence, one of the three operations that a job requires can only be processed by the first and another operat...
Conference Paper
We consider a flowshop with m machines each of which perform a specific operation of the identical parts to be processed. Two specific adjacent machines among all machines are capable of performing an additional operation required by each part, which is named as the flexible operation. The problem is to decide on the machine to perform this flexibl...
Conference Paper
The mixed model assembly line design problem includes allocating operations to the stations in the robotic cell and satisfying the demand and cycle time within a desired interval for each model to be produced. We also ensure that assignability, precedence and tool life constraints are met. Each pair of spot welding tools can process a certain numbe...
Article
Full-text available
In this study, a two-machine flowshop producing identical parts is considered. Each of the identical parts is assumed to require a number of manufacturing operations, and the machines are assumed to be flexible enough to perform different operations. Due to economical or technological constraints, some specific operations are preassigned to one of...
Article
Consider a manufacturing cell of two identical CNC machines and a material handling robot. Identical parts requesting the completion of a number of operations are to be produced in a cyclic scheduling environment through a flow shop type setting. The existing studies in the literature overlook the flexibility of the CNC machines by assuming that bo...
Article
Full-text available
In this letter, we present a mixed binary linear programming framework to investigate the impact of one-time energy costs on the overall system lifetime in wireless sensor networks. We use public-key cryptography as our representative one-time initialization operation. We show that the effect of public-key cryptography on optimal routes selection d...
Article
In this study, an m-machine flexible robotic manufacturing cell consisting of CNC machines is considered. The flexibility of the machines leads to a new class of robot move cycles called the pure cycles. We first model the problem of determining the best pure cycle in an m-machine cell as a special travelling salesman problem in which the distance...
Article
Full-text available
This paper considers the scheduling problems arising in two- and three-machine manufacturing cells configured in a flowshop which repeatedly produces one type of product and where transportation of the parts between the machines is performed by a robot. The cycle time of the cell is affected by the robot move sequence as well as the processing time...
Article
Full-text available
The focus of this study is the identical parts robotic cell scheduling problem with m machines under the assumption of process and operational flexibility. A direct consequence of this assumption is a new robot move cycle that has been overlooked in the existing literature. We prove that this new cycle dominates all classical robot move cycles cons...
Article
In this study, we consider a flexible manufacturing cell (FMC) processing identical parts on which the loading and unloading of machines are made by a robot. The machines used in FMCs are predominantly CNC machines and these machines are flexible enough for performing several operations provided that the required tools are stored in their tool maga...
Conference Paper
In this study, a three-machine flexible robotic manufacturing cell in which the CNC machines are used is considered. These machines are highly flexible and are capable of performing several different operations. Each machine is assumed to be capable of performing all of the required operations of each part. As a consequence of this assumption, a ne...
Conference Paper
In this study, a three-machine flexible robotic manufacturing cell in which the CNC machines are used is considered. These machines are highly flexible and are capable of performing several different operations. Each machine is assumed to be capable of performing all of the required operations of each part. As a consequence of this assumption, a ne...
Article
Abstract In this study, we deal with the robotic cell scheduling problem with two machines and identical parts. In an ideal FMS, CNC machines are capable of performing all the required operations as long as the required tools are stored in their tool magazines. However, this assumption may be unrealistic at times since the tool magazines have limit...
Article
In this paper, we study the problem of two-machine, identical parts robotic cell scheduling with operational $exibility. We assume that every part to be processed has a number of operations to be completed in these two machines and both machines are capable of performing all of the operations. The decision to be made includes 8nding the optimal rob...
Article
Full-text available
In this study, we deal with the robotic cell scheduling problem with two machines and identical parts. In an ideal FMS, CNC machines are capable of performing all the required operations as long as the required tools are stored in their tool magazines. However, this assumption may be unrealistic at times since the tool magazines have limited capaci...

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Projects (4)
Project
In next generation cellular networks, high reliability and quick responsiveness will be more important for users. Current network structures will not be sufficient to satisfy user demands as the demand for data has been growing each day. Therefore, we propose a new frontier, where unmanned aerial vehicles (UAVs) or drones can support the core network. Quick deployment and mobility advantages of such vehicles can be beneficial to both service providers and users. In this project, we focus on not only deciding the location of the UAVs but also assigning the users to UAVs so that the service provision is improved.
Archived project
In order to survive in today’s highly competitive market that can be defined with huge variation in customer demand and very short product lives, the manufacturing systems must be very flexible. However, installing such flexible systems is not enough alone. In order to operate these systems efficiently some important problems must be tackled. Determination of methods to operate and manage these systems efficiently is very important to get the maximum benefit from the installation of such systems. In accordance with this, the number of researches handling such systems increases gradually in the literature. In this study, different from the classical flowshop scheduling and assembly line balancing literature, the workstations, which can be composed of either human operators or machines, are assumed to possess different types of flexibility. Basically, it is assumed that the workstations have the capability of performing different operations and the process times of these operations are controllable. If the workstations are composed of human operators, such flexibilities are evident: by cross training the operators they can be made capable of performing different operations. At the same time, the process time of an operation is a function of the level of resources like the amount of operators, equipment and energy, allocated to that operation. Consequently, these times can be controllable. A similar situation arises when highly automated CNC machines are used in the workstations. The necessary tools can be stored in the tool magazines of these machines. Whenever a different tool is required for an operation, the tool can be changed in negligibly small amount of time. As a result, these machines are capable of performing different operations. On the other hand, by adjusting some parameters such as the speed, the feed rate and the depth of cut, the processing times of the operations can be controlled. In this study, the benefits of these two types of flexibilities in terms of the throughput rate and manufacturing cost will be quantified. Additionally, it is aimed to find procedures for the assignment of operations to the machines, the scheduling of the parts to be processed, and the determination of the process times of the operations in order to maximize the throughput rate and to minimize the manufacturing cost.
Project
In this study, we consider the robotic cell design problem where single or dual gripper robots are used and identical parts are produced. The processing of the parts are performed by the machines and the transportation of the parts between the machines and the loading/unloading of the machines are performed by a single material handling robot. Each part has a number of operations to be processed on the machines. These operations are to be assigned to the machines satisfying the precedence constraints among them and satisfying a pre-specified throughput rate with the objective of minimizing the number of machines used in the system. Single gripper robots can hold one part at any time instant, whereas dual gripper robots can hold two parts simultaneously. Since the robots follow a computer code and since it is easy to use and control and they provide optimal solutions for identical parts case, cyclic production models will be considered. In such models, the robot follows the same set of activities indefinitely. Among these models, 1-unit cycles, in which a single repetition of the cycle produces a single part, will be considered. As a result, the problem is to assign the operations to the machines and to determine the optimal 1-unit cycle such that a specified throughput rate is satisfied, with the objective of minimizing the number of machines and as a secondary objective, minimizing the cycle time.