Faculty of Engineering

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Browsing by Institution Author "ADAM, Evşen Yanmaz"

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    ArticlePublicationOpen Access
    Connectivity considerations for mission planning of a search and rescue drone team
    (TÜBİTAK, 2020) Adam, Evşen Yanmaz; Electrical & Electronics Engineering; ADAM, Evşen Yanmaz
    In this paper, we analyze the mission success performance and mission times of centralized, distributed, and hybrid path-planning methods for a drone team whose mission is to find a target and inform the ground control. We propose two methods that integrate connectivity into the search mission path decisions. We observe that even though the coverage path-planning leads to lower search times, when target connectivity is also required, schemes that incorporate end-end connectivity into path planning result in at least 50% better mission times for small communication ranges and lower number of drones. Our results also indicate that methods to efficiently allocate resources to search and communication tasks in mission-oriented drone networks need to be designed.
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    Joint or decoupled optimization: Multi-UAV path planning for search and rescue
    (Elsevier, 2023-01-01) Adam, Evşen Yanmaz; Electrical & Electronics Engineering; ADAM, Evşen Yanmaz
    In this paper, we focus on path planning of drone teams deployed for search and rescue missions. The goal of the mission is to detect a target, inform the rescue personnel at the ground base station (BS), and form a communication relay chain between the target and the BS as fast as possible. Such missions where both detection and connectivity requirements need to be met can be planned by formulating (i) a single objective optimization problem with connectivity constraints; (ii) a multi-objective optimization problem where mission and connectivity needs are jointly optimized or (iii) mission and connectivity tasks are optimized decoupled from each other. Both joint and decoupled approaches have merit in terms of mission times, connectivity, cost and/or implementation. In this paper, we compare selected joint and decoupled multi-drone path planning approaches from mission and connectivity perspectives. We illustrate the trade-off between performance metrics from both viewpoints and show that depending on the available resources (e.g., number of drones) and the search area most suitable planner can change. We then propose a hybrid planner that utilizes joint optimization for the search drones and decoupled optimization for the relay drones. Hence, the proposed scheme has a flexibility due to allowing different search path planners to be used and a connectivity-wise better pre-mission plan. Our analysis shows that the hybrid scheme results in a better connectivity and total mission time if there are enough drones, but for very small number of search drones, hybrid scheme leads to a higher mission time than the joint scheme due to reservation of drones for relaying purposes.
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    ArticlePublicationOpen Access
    Leveraging connectivity for coverage in drone networks for target detection
    (Balkan Yayın, 2019) Adam, Evşen Yanmaz; Electrical & Electronics Engineering; ADAM, Evşen Yanmaz
    Target or event detection is one of the main applications of drone networks. Several cooperative search algorithms have been proposed for teams of unmanned aerial vehicles (UAVs), where the goal is to minimize search time or maximize detection probability. In these works, connectivity often is considered a constraint in enabling cooperation. In this paper, we approach the target detection problem in drone networks from both detection and connectivity viewpoints. Our goal is not only to find a stationary target but also to inform the ground personnel (e.g., a rescue team) about the status of the target over a multi-hop communication chain. We analyze the performance of our coverage-based and connectivity-based path planning algorithms in terms of probability and time of detection as well as notification. We show that there is a trade-off between coverage and connectivity and with limited number of drones both aspects need to be considered for successful mission completion.
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    Live multicast video streaming from drones: an experimental study
    (Springer Nature, 2020-01-01) Muzaffar, R.; Adam, Evşen Yanmaz; Raffelsberger, C.; Bettstetter, C.; Cavallaro, A.; Electrical & Electronics Engineering; ADAM, Evşen Yanmaz
    We present and evaluate a multicast framework for point-to-multipoint and multipoint-to-point-to-multipoint video streaming that is applicable if both source and receiver nodes are mobile. Receiver nodes can join a multicast group by selecting a particular video stream and are dynamically elected as designated nodes based on their signal quality to provide feedback about packet reception. We evaluate the proposed application-layer rate-adaptive multicast video streaming over an aerial ad-hoc network that uses IEEE 802.11, a desirable protocol that, however, does not support a reliable multicast mechanism due to its inability to provide feedback from the receivers. Our rate-adaptive approach outperforms legacy multicast in terms of goodput, delay, and packet loss. Moreover, we obtain a gain in video quality (PSNR) of 30%\for point-to-multipoint and of for multipoint-to-point-to-multipoint streaming.
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    MAC layer performance of multi-hop vehicular VLC networks with CSMA/CA
    (IEEE, 2020) Eldeeb, Hossıen Badr; Adam, Evşen Yanmaz; Uysal, Murat; Electrical & Electronics Engineering; ELDEEB, Hossien Badr Hossien; ADAM, Evşen Yanmaz; UYSAL, Murat
    Majority of works in the field of vehicular visible light communication (VLC) networks are based on some ideal assumptions. Particularly, the ideal Lambertian pattern is assumed for channel modeling and only a simple point-to-point transmission link is considered in the network analysis. In this paper, we investigate the performance of multi-hop vehicular VLC networks based on the recent reference channel models and upcoming standards like IEEE 802.15.7r1 and 802.11bb. The impact of the asymmetrical radiation pattern of car headlamps, as well as the road reflectance are considered. In MAC layer, we deploy carrier-sense-multiple-access with collision-avoidance (CSMA/CA) as the medium-access protocol.
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    Maintaining connectivity for multi-UAV multi-target search using reinforcement learning
    (Association for Computing Machinery, Inc, 2023-10-30) Güven, İslam; Adam, Evşen Yanmaz; Electrical & Electronics Engineering; ADAM, Evşen Yanmaz; Güven, İslam
    We propose a dynamic path planner that uses a multi-Agent reinforcement learning (MARL) model with novel reward functions for multi-drone search and rescue (SAR) missions. We design a mission environment where a multi-drone team covers an area to detect randomly distributed targets and inform the ground base station (BS) by continuously forming relay chains between the targets and the BS. The training procedure of the agents includes a convolutional neural network (CNN) that uses images which represent trajectory histories and connectivity states of each environment entity such as drones, targets, BS. Agents take actions and get feedback from the environment until the mission is completed. The model is trained with multiple missions with randomized target locations. Our results show that the trained model successfully produces mission plans such that the multi-drone system searches the area efficiently while dynamically forming relay chains. The proposed dynamic method leads up to 45% better total detection and mission times in comparison to a pre-planned optimized path planner.
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    Positioning aerial relays to maintain connectivity during drone team missions
    (Elsevier, 2022-04-01) Adam, Evşen Yanmaz; Electrical & Electronics Engineering; ADAM, Evşen Yanmaz
    Approaches that aim to maintain the connectivity of unmanned aerial vehicles (UAVs) or drones either utilize cellular networks or propose to jointly optimize connectivity needs with other mission tasks. Therefore, most solutions either rely on existing infrastructure or are optimized for specific applications. Use of UAVs to assist the connectivity of ground nodes is commonly proposed. In this work, we deploy UAVs as relays to support mission-oriented UAV networks in order to decouple the mission and communication tasks. We propose a modular relay positioning and trajectory planning algorithm that guarantees connectivity of the UAV mission team with minimum number of relays and feasible trajectories, where the cost, network structure and setup can be changed, allowing its use for different types of missions, without relying on infrastructure. We propose different approaches to relay position decisions and compare the proposed schemes with an ideal scheme and a Voronoi-based benchmark scheme. Our results show that different solutions are applicable for achieving fewer number of relay nodes, higher utilization or lower number of hops between the nodes. With the proposed scheme the maximum number of relays in the air can be reduced by up to 40% and utilization can be increased up to 50% in comparison to the benchmark scheme, with less average traveled distances and average velocities for the relay nodes. These advantages come with a cost of higher maximum number of hops compared to the benchmark.
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    Take the field from your smartphone: Leveraging UAVs for event filming
    (IEEE, 2020-08-01) Natalizio, E.; Zema, N. R.; Adam, Evşen Yanmaz; Pugliese, L. D. P.; Guerriero, F.; Electrical & Electronics Engineering; ADAM, Evşen Yanmaz
    This paper formulates the Sport Event Filming with Connectivity Constraints (SEF-C-2) problem. The SEF-C-2 problem is an event coverage problem, which exploits a team of Unmanned Aerial Vehicles (UAVs) over a limited field in order to track the movements of an object (e.g., of the ball) and to deliver a video stream of the events (e.g. , ball passes, goals) to the spectators meeting certain timeliness and video quality criteria. Assuming a priori knowledge of the whole sequence of actions, first a novel mathematical model is introduced that determines a sequence of movements for the UAVs, such that the timeliness of the filming is maximized and the total traveled distance is minimized. Then, dynamic, artificial potential function based, distributed UAV movement schemes that have no a priori knowledge of the sequence of game actions are proposed to optimize networking performance. Extensive simulations are used to analyze the performance in terms of video transmission quality and show that the proposed schemes outperform existing schemes.
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    Unmanned aerial vehicle relay networks
    (Help Cookies Privacy Statement Accessibility Modern Slavery Act Statement Legal notices The Institution of Engineering and Technology, 202) Adam, Evşen Yanmaz; Electrical & Electronics Engineering; Davoli, L.; Ferrari, G.; ADAM, Evşen Yanmaz
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