Blar i forfatter "Ho, Tu Dac"

Viser treff 1-10 av 10

    • Enhancement of Vehicular Visible Light Communication Using Spherical Detector and Custom Lens Combinations 

      Yahia, Selma; Meraihi, Yassine; Amar, Ramdane-Cherif; Ho, Tu Dac; Eldeeb, Hossien (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-28)
      Vehicular Visible light communication (VLC) technology has recently attracted much interest from researchers and scientists. This technology enables connectivity between vehicles and infrastructures along the road by using vehicles’ headlights and taillights as wireless transmitters. The reliability of vehicle-to-vehicle (V2V) VLC systems is affected by several factors, such as car mobility, optics ...

    • Evaluations of UAV-enabled FSO Communications in the Arctic 

      Pottoo, Sahil Nazir; Ellingsen, Pål Gunnar; Ho, Tu Dac (Journal article; Tidsskriftartikkel, 2022-02-16)
      This paper investigates the feasibility of using free space optics (FSO) for communication between multiple hovering unmanned aerial vehicles (UAVs) and a detection unit (DU) in the Arctic. The uniqueness that sets apart UAV-based FSO systems from conventional FSO systems is the dynamics of the system since location and inclination of the UAV changes over time due to wind load and UAV oscillations. ...

    • Improving Geopolymer Characteristics with Addition of Poly-Vinyl Alcohol (PVA) Fibers 

      Ekaputri, Januarti Jaya; Fujiyama, Chikako; Chijiwa, Nobuhiro; Ho, Tu Dac; Nguyen, Hung Thanh (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-20)
      This paper presents the benefits of PVA fibers in improving the mechanical properties of class F fly-ash-based geopolymer concrete. The activator used in the geopolymer was 8M sodium hydroxide (NaOH) and sodium silicate (Na<sub>2</sub>SiO<sub>3</sub>), with a mass ratio of Na<sub>2</sub>SiO<sub>3</sub> to NaOH varied from 1.5 to 2.5. Cylindrical specimens with a diameter of 100 mm and a height of ...

    • Path planning for UAV harvesting information from dynamical wireless sensor nodes at sea 

      Ho, Tu Dac; Grøtli, Esten Ingar; Johansen, Tor Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-16)
      A system of several wireless sensor nodes and one unmanned aerial vehicle (UAV) is considered in this research. The nodes are only floating and drifting with the sea stream. The UAV will be operating as a data mule to gather sensing information from wireless sensor nodes. Unlike prior studies, this paper addressed a realistic ocean model for the nodes movements which will be the references to the ...

    • Performance Analysis of Bidirectional Multi-Hop Vehicle-to-Vehicle Visible Light Communication 

      Refas, Souad; Acheli, Dalila; Yahia, Selma; Meraihi, Yassine; Ramdane-Cherif, Amar; Van, Nhan Vo; Ho, Tu Dac (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-14)
      Vehicular visible light communication (VVLC) has emerged as a promising field of research, garnering considerable attention from scientists and researchers. VVLC offers a potential solution to enable connectivity and communication between travelling vehicles along the road by using their existing headlights (HLs) and taillights (TLs) as wireless transmitters and integrating photodetectors (PDs) ...

    • PSO and Kalman Filter-Based Node Motion Prediction for Data Collection from Ocean Wireless Sensors Network with UAV 

      Ho, Tu Dac; Grøtli, Esten Ingar; Johansen, Tor Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-13)
      In this paper, we consider a wireless sensor network of nodes at the sea surface drifting due to wind and sea currents. In our scenario an Unmanned Aerial Vehicle (UAV) will be used to gather data from the sensor nodes. The goal is to find a flyable path which is optimal in terms of sensor node energy consumption, total channel throughput between the UAV and sensor nodes, flight time for the UAV and ...

    • PSO and Kalman Filter-Based Node Motion Prediction for Data Collection from Ocean Wireless Sensors Network with UAV 

      Ho, Tu Dac; Johansen, Tor Arne; Grøtli, Esten Ingar (Conference object; Konferansebidrag, 2021-01)
      In this paper, we consider a wireless sensor network of nodes at the sea surface drifting due to wind and sea currents. In our scenario an Unmanned Aerial Vehicle (UAV) will be used to gather data from the sensor nodes. The goal is to find a flyable path which is optimal in terms of sensor node energy consumption, total channel throughput between the UAV and sensor nodes, flight time for the ...

    • Secondary Network Throughput Optimization of NOMA Cognitive Radio Networks Under Power and Secure Constraints 

      Vo, Van Nhan; Viet Hung, Dang; Tran, Hung; Ha, Dac-Binh; Le, Cong; Ho, Tu Dac; Chakchai, So-In (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-31)
      Recently, the combination of cognitive radio networks with the nonorthogonal multiple access (NOMA) approach has emerged as a viable option for not only improving spectrum usage but also supporting large numbers of wireless communication connections. However, cognitive NOMA networks are unstable and vulnerable because multiple devices operate on the same frequency band. To overcome this drawback, ...

    • Secondary Network Throughput Optimization of NOMA Cognitive Radio Networks Under Power and Secure Constraints 

      Vo, Van Nhan; Dang, Viet-Hung; Tran, Hung; Ha, Dac-Binh; Le, Cong; Ho, Tu Dac; So-In, Chakchai (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-31)
      Recently, the combination of cognitive radio networks with the nonorthogonal multiple access (NOMA) approach has emerged as a viable option for not only improving spectrum usage but also supporting large numbers of wireless communication connections. However, cognitive NOMA networks are unstable and vulnerable because multiple devices operate on the same frequency band. To overcome this drawback, ...

    • Throughput Optimization for NOMA Energy Harvesting Cognitive Radio with Multi-UAV-Assisted Relaying under Security Constraints 

      Dang, Viet-Hung; Nguyen, Le-Mai-Duyen; Vo, Van Nhan; Tran, Hung; Ho, Tu Dac; Chakchai, So-In; Surasak, Sanguanpong (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-28)
      This paper investigates the throughput of a non-orthogonal multiple access (NOMA)-based cognitive radio (CR) system with multiple unmanned aerial vehicle (UAV)-assisted relays under system performance and security constraints. We propose a communication protocol that includes an energy harvesting (EH) phase and multiple communication phases. In the EH phase, the multiple UAV relays (URs) harvest ...