Yazar "Potirakis, Stelios M." seçeneğine göre listele

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    Analyzing the Water Budgets of Reservoirs by Using Autonomous Mini Boats
    (Trans Tech Publications Ltd, 2014) Tuna, Gurkan; Arkoc, Orhan; Potirakis, Stelios M.; Nefzi, Bilel
    The calculation and estimation of water deposits in both man-made reservoirs and natural reservoirs is very important in several aspects. For surface water reservoirs in hot and dry environments, evaporation is an important factor in their operations since it can cause significant water loss. Typically, hydrologists use different computer models which take into account the effects of evaporation to estimate the water budgets of reservoirs. An important step required for this repetitive process is to calculate the current water budget of a reservoir. In this paper, an autonomous system is proposed aiming to support this step. Unlike the common approaches, the proposed system is fast and accurate, and requires no human effort. In this system, first, an autonomous mini boat follows predefined trajectories at a reservoir and builds a depth map (bathymetric map) of it. Then, an onboard computer calculates the water budget of the reservoir. The proposed system is portable and a single system can periodically serve at several water reservoirs. Field tests in the water reservoir of Kirklareli (Kirklareli dam), Turkey, are in progress.
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    ANN-Based Control of a Multiboat Group for the Deployment of an Underwater Sensor Network
    (Hindawi Ltd, 2014) Michailidis, Emmanouel T.; Tuna, Gurkan; Gezer, Gulsum; Potirakis, Stelios M.; Gulez, Kayhan
    Underwater sensor networks (USNs) can be used for several types of commercial and noncommercial applications. However, some constraints resulting from the nature of aquatic environments severely limit their use. Due to constraints such as large propagation latency, low-bandwidth capacity, and short-distance communications, a large number of USN nodes are deployed to provide reliability in most applications. In this study, an unattended deployment approach based on the use of an autonomous boat group is proposed. A map of the deployment zone and optimal locations of USN nodes are fed into the onboard computers of the boat group. After processing these data and determining paths to be followed, the boat group deploys sensor nodes at predetermined locations. During the deployment, the boat group is controlled by an artificial neural network-(ANN-) based control system for reducing path errors. A set of performance evaluations is given to prove efficiency of the proposed control system. Performance results show that the boat group can successfully follow a predefined path set and deploy USN nodes. The tradeoffs between energy consumptions, end-to-end delay, and number of hops between underwater relay nodes of energy-efficient USN are also examined. The results indicate that increasing the number of hops reduces the total energy consumption and the end-to-end delay.
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    ANN-Based Estimation of Groundwater Quality Using a Wireless Water Quality Network
    (Hindawi Ltd, 2014) Kilicaslan, Yilmaz; Tuna, Gurkan; Gezer, Gulsum; Gulez, Kayhan; Arkoc, Orhan; Potirakis, Stelios M.
    Water is essential for life. Considering its importance for humans, it must be periodically analyzed to ensure its quality. In this study, a wireless water quality network is deployed to collect water quality parameters periodically and an artificial neural network-based estimation method is proposed to estimate groundwater quality. Estimating groundwater quality enables the authorities to take immediate actions for ensuring water quality. Compared to traditional water quality analysis methods, the proposed method has the advantage of letting the authorities know the quality of their water resources beforehand. A set of simulation studies given in this paper proves the efficiency and accuracy of the proposed method.
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    Performance Evaluation of a Communication Protocol for Vital Signs Sensors Used for the Monitoring of Athletes
    (Hindawi Publishing Corporation, 2014) Kiokes, George; Vossou, Clio; Chatzistamatis, Panagiotis; Potirakis, Stelios M.; Vassiliadis, Savvas; Prekas, Kleanthis; Tuna, Gurkan
    Monitoring vital signs in athletes, mainly during training, is of crucial importance for both the athlete and the coach, in order to avoid overtraining. Overtraining is an extreme state of fatigue that forces athletes to rest for several weeks having a negative impact on athlete's performance, health, and daily life. A wireless sensor network (WSN) combines embedded computing technology with communication technology in order to collect information of the network coverage area and send it to the observer. In this paper, we present results of system's performance evaluation for the IEEE 802.15.4 standard, including the physical (PHY) layer and media access control (MAC) sublayer, in order to collect and store large sets of athletes' data as well as providing results about network values such as end-to-end delay, load, and throughput captured from global and objects statistics.
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    A Wireless Network of Acoustic Sensors for Environmental Monitoring
    (Trans Tech Publications Ltd, 2014) Potirakis, Stelios M.; Nefzi, Bilel; Tatlas, N. -A.; Tuna, Gurkan; Rangoussi, M.
    A distributed microelectronic system for the sound/acoustic monitoring of areas of environmental interest, based on a wireless network of acoustic sensors (microphones), and the automated generation of multi-level sound maps for environmental assessment has been recently proposed. This contribution focuses on the relation between the density of the wireless nodes and node operational parameters, like the required communication rate, data compression and power autonomy, in each one of the proposed area coverage schemes/network architectures. The results provide the grounds both for the selection of the hardware architecture on network and on node level, but also for the decision on the distribution of the processing effort between the local and the central processing units.
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    Wireless sensor network-based communication for cooperative simultaneous localization and mapping
    (Pergamon-Elsevier Science Ltd, 2015) Tuna, Gurkan; Gungor, Vehbi Cagri; Potirakis, Stelios M.
    This paper presents a novel approach of using a Wireless Sensor Network (WSN) as the communication means for Multi-Robot, Cooperative, Simultaneous Localization and Mapping (CSLAM) applications investigating the associated design challenges and suggesting corresponding solutions. Although the proposed approach brings several benefits including an increased coverage and communication range, self-organization capabilities, quick deployment, and flexible architecture, the realization is interrelated with performance in terms of energy efficiency and reliability. In this respect, the applicability of the WSNs for the presented approach is investigated. Centralized and distributed map merging methods in WSN-based CSLAM are evaluated in detail and the impacts of packet delays and losses on the performance of CSLAM algorithms are shown. Additionally, the involved network congestion and contention dynamics are presented, while the effects of observation range, speed, time intervals between observations, and odometry readings on the SLAM accuracy are shown based on an extensive set of simulation studies. (C) 2014 Elsevier Ltd. All rights reserved.
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    Wireless Sensor Network-based Water Quality Monitoring System
    (Trans Tech Publications Ltd, 2014) Tuna, Gurkan; Nefzi, Bilel; Arkoc, Orhan; Potirakis, Stelios M.
    Water is vital for both nature and human beings. The construction of dams and embankments, the irrigation practices, and the anthropogenic activities influence water quality. In order to control water quality, it is essential to understand the sources of pollutants. Water quality monitoring requires the collection of large numbers of samples and long delays until the results are available. Therefore, rapid monitoring of water quality is very important. In this respect, numerous systems exist for this kind of automatic monitoring. In this study, we propose a wireless sensor network (WSN)-based monitoring system controlled by a web-based online interface which allows the remote monitoring via Internet. This brings advantages over traditional monitoring systems in terms of cost effectiveness, portability and applicability. Field tests in the water reservoir of Kirklareli (Kirklareli dam), Turkey, are in progress.