Yazar "Akkas, Mustafa Alper" seçeneğine göre listele

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    IoT supported smart home for the elderly
    (Elsevier, 2020) Sokullu, Radosveta; Akkas, Mustafa Alper; Demir, Eren
    Continuously progressing technology helps improve human living standards and make human life easier. A large portion of these developments is targeting the healthcare sector and especially in the last decade has been focused on helping elderly patients extend their independent existence in their preferred environments. In this article, we present a smart home IoT based system for elderly people and people with partial memory loss (MCI patients, dementia patients etc) which ensures their safety and provides early warnings to help them overcome small everyday problems typical for such disorders. Data is continuously collected from various ambient sensors and is used for the contextual detection of their activities. Unobtrusively monitoring the patient's behaviour in his/her home is assured as well as providing necessary data to relatives and/or caregivers. An emergency wristband is added to deal with extraordinary and dangerous situations like unexpected fall, gas/water left open in the house, etc. The developed prototype is a low-cost solution, under 100 USD, in which low energy consumption and ease of integration help greatly increase its applicability. (C) 2020 Elsevier B.V. All rights reserved.
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    Joint Resource Allocation for Terahertz Band Drone Communications
    (Ieee-Inst Electrical Electronics Engineers Inc, 2024) Saeed, Akhtar; Erdem, Mikail; Saleem, Ammar; Gurbuz, Ozgur; Akkas, Mustafa Alper
    This article proposes a joint resource allocation approach for Terahertz (THz) band (0.75-4.4 THz) drone-to-drone communications, studying spectrum and power allocation together with antenna beamwidth adjustment. Considering various drone (mis)alignment and mobility scenarios under a 3D sectored antenna model, the capacity of the proposed spectrum allocation scheme, MaxActive, is compared to existing Common Flat Band (CFB) and standard (STD) schemes, each with water-filling (WF) and equal power (EP) allocations. Results show that up to 6 orders of magnitude improvements are observed with beamwidth optimization, and MaxActive with EP performs close to CFB and STD schemes with WF in all scenarios, even under realistic beam misalignment fading instances (low and high). For drone-to-drone communications, our results prove that the THz band can provide high capacity, in the order of Tbps, which can be preserved well with beam alignment/adjustment. Evaluating also the complexity of all considered resource allocation techniques, it is concluded that MaxActive with EP allocation stands out as the most feasible scheme in terms of practical implementation with the best performance.
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    Low-cost and high-performance channel access strategies for Internet of Nano-Things applications
    (Elsevier B.V., 2024) Sahin, Emre; Akkas, Mustafa Alper; Dagdeviren, Orhan
    Nanodevices, which are only a few nanometers (nm) in size, are interconnected to form the Internet of Nano-Things (IoNT) that performs complex operations. One of the key challenges is ensuring efficient channel access control for nanodevices, especially when dealing with large network sizes. Medium access control (MAC) protocols serve this purpose, but traditional approaches are not practical due to the inherent constraints of nanodevices. In this paper, we propose two novel MAC protocols for IoNT applications. The first protocol, Slot Assignment-Based (SAB) MAC, is a contention-free method relying on scheduling. In contrast to its counterparts, it enables simultaneous packet transmission through Time Spread On-Off Keying (TS-OOK), effectively minimizing the collision probability and end-to-end delay. The second protocol, Receiver-Initiated and Directed (RID) MAC, adopts a contention-based approach to reduce unnecessary transmissions caused by flooding. It achieves this by limiting the number of active nanodevices within a time interval using directional antennas without incurring scheduling overhead. We evaluated the performance of these protocols through comprehensive simulations, comparing them with counterparts in terms of packet transmission success, energy consumption, end-to-end delay and setup overhead. In dense topologies, SAB-MAC outperforms Transparent (TRN) MAC by approximately twice the packet transmission success reaching up to 95.73%. It accomplishes this with 1000 times lower end-to-end delay and reduced setup overhead than Time Division Multiple Access (TDMA). Conversely, RID-MAC achieves twice the packet transmission success of TRN-MAC and ten times that of unicast-based methods, all with lower end-to-end delay and nearly equivalent energy consumption. Consequently, due to its superior performance SAB-MAC is the optimal choice for communication between nanorouters (NRs). However, RID-MAC is more suitable for communication between nanosensors (NSs), as it incurs no setup overhead. © 2023
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    THz band drone communications with practical antennas: Performance under realistic mobility and misalignment scenarios
    (Elsevier, 2025) Saeed, Akhtar; Erdem, Mikail; Gurbuz, Ozgur; Akkas, Mustafa Alper
    For 6G non-terrestrial communications, drones will offer uninterrupted connectivity for surveillance, sensing, and localization. They will also serve as drone base stations to support terrestrial base stations, providing large bandwidth, high-rate, and ultra-reliable low latency services. In this paper, for the first time in the literature, we depict the true performance of Terahertz (THz) band communications among drones by applying various channel selection and power allocation schemes with practical THz antennas within (0.75-4.4) THz under realistic mobility and misalignment scenarios. Through numerical simulations, we unveil the capacity of drone links under different channel selection and power allocation schemes within 10s to 100s of Gbps at distances (1-100) m, when drones are in motion and subject to (mis)alignment due to mobility and even under beam misalignment fading. However, when exposed to real drone mobility traces, the performance of all channel selection schemes drops significantly, sometimes by up to six orders of magnitude, due to the occasional reverse orientations of antennas. In addition to the capacity analysis, we report available frequency bands (transmission windows) considering all schemes and mobility patterns. We also identify a band that is commonly available under all considered mobility and misalignment settings, and we evaluate its performance in terms of spectral and energy efficiencies, which can be useful in designing THz transceivers for drone communications. Our findings emphasize the essence of active beam control solutions to achieve the desired capacity potential of THz drone communications, while also highlighting the challenges of utilizing the THz band for drone communications.