Browsing by Author "Ok, Ahmet Enes"

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Çok robotlu sistemlerde görev ve yol planlaması
(2025) Ok, Ahmet Enes; Özsoyeller, Deniz
Wireless Sensor Networks (WSNs) have been utilized in a wide range of applications such as environmental monitoring, precision agriculture, industrial automation, disaster response, and military surveillance. A critical challenge that affects the system lifetime is the limited battery capacity of the sensors which is mostly consumed by data transmission. In this thesis, we study the sensor data collection problem with a team of unmanned aerial vehicles (UAVs) and a single unmanned ground vehicle (UGV). The UAVs work as data collectors while the UGV provides recharging and data-relaying services to the UAVs. We consider partitioned WSN settings, where the communication graph on the initial locations of all sensors is not connected. That is, a sensor can be single or a member of networked sensors. Each UAV has a fixed capacity that it reserves for storing sensor data. The objective is to minimize the time required for UAVs to collect the data of all sensors such that no UAV exceeds its sensor data capacity. To solve this problem, we propose a capacity-constrained data collection algorithm that plans energy-aware paths for UAVs so that they cooperatively locate the sensors and collect data from them. The algorithm also determines the UAV-UGV rendezvous locations and plans the UGV's path. Our approach combines the techniques including environment decomposition, clustering the sensors, and solving the capacitated vehicle routing problem (CVRP). In simulations, we validate the performance of our algorithm varying the key performance metrics including the number of UAVs, number of sensors, communication range, and environment size.
Data Collection with a Team of Capacity-Constrained Unmanned Aerial Vehicles Assisted by a Mobile Recharger
(Elsevier, 2025) Ozsoyeller, Deniz; Ok, Ahmet Enes
Wireless Sensor Networks (WSNs) have been utilized in various applications such as environmental monitoring, precision agriculture, disaster response, and military surveillance. A critical challenge that affects the system lifetime is the limited battery capacity of the sensors. In this paper, we study the sensor data collection problem with a team of unmanned aerial vehicles (UAVs) and a single unmanned ground vehicle (UGV). The UAVs work as data collectors while the UGV provides recharging and data-relaying services to the UAVs. We envision partitioned WSN scenarios, where the communication graph on the initial locations of all sensors is not connected. The objective is to minimize the total time required for the UAVs to collect the data of all sensors. We present a multi-stage online data collection algorithm that plans the paths for the UAVs that do not know the locations of the sensors in advance and are subject to both energy and storage capacity constraints. Our algorithm also plans the path of the UGV and determines the recharging sites for UGV-UAV rendezvous considering not only the limited energy capacity of the UAVs but also the total units of sensor data to be collected by each UAV. We analyze its performance theoretically, in extensive simulations, and on well-known benchmark instances.