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Robust Precoding and Postcoding for Multicell Multiuser Transmission using Imperfect CSI
Hung Nguyen-Le,Vien Nguyen-Duy-Nhat,Chien Tang-Tan,Vo Nguyen Quoc Bao 한국통신학회 2016 Journal of communications and networks Vol.18 No.5
This paper studies the problem of precoding and post-coding design for multicellmultiuser downlink transmissions in theabsence of perfect channel state information (CSI). Using statisti-cal information of imperfect CSI, an iterative multiuser multicelltransceiver design is formulated by minimizing the mean squarederror (MSE) cost function of signal and leakage interference underper-base station power constraint (PBPC). The convergence of theiterative precoding and postcoding algorithm is verified by analyt-ical and empirical results. The proposed precoding and postcodingalgorithm offers a low computational complexity and robustnessagainst CSI imperfection.
Key Determinants for Users Intention to Use Smarthome Devices in Vietnam
Nguyen, Thi-Hong-Linh,Duong, Minh-Hung,Nguyen, Hai-Dang,Vo, Dang-HongNgan,Vu, Duy-Phuong-Trinh,Le, Hoanh-Su Korea Multimedia Society 2018 The journal of multimedia information system Vol.5 No.4
Smarthome is one of the remarkable fields of the industrial revolution 4.0, which are popular in many countries such USA, EURO, Japan and Korea. However, how Vietnamese people are considering and having intension to use smarthome devices is still a question for marketers and researchers. This study develops a comprehensive research model that can explain potential customers' behavioral intentions to adopt and use Smarthome services in Viet Nam and figure which key factors affect the intention. This study proposes and validates a new theoretical model that extends the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2). The model consists of eight factors that affect one element (Behavioral Intention), specifically: Habits, Perceived usefulness, Perceived ease of use, Trust, Innovativeness Personal, Perceived value, Hedonic motivations and Social influences. Data were collected from 304 Vietnamese citizens by sending the email to survey questionnaire, direct contact with the experienced smarthome users. Through regression analysis, data from samples were analysed with SPSS 20 software and verification of hypotheses, the results show the key determinants affecting the intention to use smarthome appliances in Vietnam: Perceived Value, Social Influence, Perceived Usefulness, Perceived Ease of Use and Trust. From this result, several recommendations have been suggested to to smarthome devices vendors and marketer to improve products as well as marketing approaches to meet customer needs.
Nguyen Phuong Tung,Nguyen Thi Phuong Phong,Nguyen Hoang Duy,Nguyen Quoc Hung 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
This research was conducted to experimentally screen the suitability of acrylamido-2- methylpropane sulfonic acid-acrylamide (AMPS-AM) copolymer-based nanogels for using as sealants to shut-off water channels in the high-temperature and high-salinity reservoir conditions of the White Tiger oil feld. Via in situ intercalative free-radical copolymerization, nanogels have been prepared from montmorillonite-alkyl ammonium clay, AMPS and AM. Two primary compositions of nanogel systems were chosen. A mixture of hexamethylenetetramine (HMTA)/phenyl acetate (PhAc) was used as a crosslinking system. The results obtained from screening the gel properties by using the bottle test method, the test under nitrogen pressure and core ooding under imitated reservoir conditions show that the NANOSEAL-1 and the NANOSEAL-2 nanogels can well satisfy the VietsovPetro (VSP) technical requirements for water isolation materials. This research was conducted to experimentally screen the suitability of acrylamido-2- methylpropane sulfonic acid-acrylamide (AMPS-AM) copolymer-based nanogels for using as sealants to shut-off water channels in the high-temperature and high-salinity reservoir conditions of the White Tiger oil feld. Via in situ intercalative free-radical copolymerization, nanogels have been prepared from montmorillonite-alkyl ammonium clay, AMPS and AM. Two primary compositions of nanogel systems were chosen. A mixture of hexamethylenetetramine (HMTA)/phenyl acetate (PhAc) was used as a crosslinking system. The results obtained from screening the gel properties by using the bottle test method, the test under nitrogen pressure and core ooding under imitated reservoir conditions show that the NANOSEAL-1 and the NANOSEAL-2 nanogels can well satisfy the VietsovPetro (VSP) technical requirements for water isolation materials.
Nguyen Duy-Hung,박선희,김정중 한국방재학회 2018 한국방재학회논문집 Vol.18 No.7
In this article, the effect of latex polymer modification on improving the impact resistance of cement pastes has been investigated. The control cement mixture was proposed with water-cement ratio of 0.5. Based on that, the cement pastes were modified by partially substituting water content with Styrene-Butadiene Rubber (SBR) latex. The mixture ratios were prepared by adjusting the various SBR latex dosages from 5 wt % to 20 wt % of water content. The specimens of modified pastes in the hardened state were tested by Charpy impact experiment and compared to the pure ones after 7, 14, 28, 45, and 60 days of curing. The observation results showed that there is a remarkable improvement in the impact resistance of modified cement pastes. Further, the optimal SBR latex dosage of 10% was proposed.
Robust Precoding and Postcoding for Multicell Multiuser Transmission using Imperfect CSI
Nguyen-Le, Hung,Nguyen-Duy-Nhat, Vien,Tang-Tan, Chien,Bao, Vo Nguyen Quoc The Korea Institute of Information and Commucation 2016 Journal of communications and networks Vol.18 No.5
This paper studies the problem of precoding and post-coding design for multicell multiuser downlink transmissions in the absence of perfect channel state information (CSI). Using statistical information of imperfect CSI, an iterative multiuser multicell transceiver design is formulated by minimizing the mean squared error (MSE) cost function of signal and leakage interference under per-base station power constraint (PBPC). The convergence of the iterative precoding and postcoding algorithm is verified by analytical and empirical results. The proposed precoding and postcoding algorithm offers a low computational complexity and robustness against CSI imperfection.
Safe Reinforcement Learning-based Driving Policy Design for Autonomous Vehicles on Highways
Hung Duy Nguyen,Kyoungseok Han 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.12
Safe decision-making strategy of autonomous vehicles (AVs) plays a critical role in avoiding accidents. This study develops a safe reinforcement learning (safe-RL)-based driving policy for AVs on highways. The hierarchical framework is considered for the proposed safe-RL, where an upper layer executes a safe explorationexploitation by modifying the exploring process of the ε-greedy algorithm, and a lower layer utilizes a finite state machine (FSM) approach to establish the safe conditions for state transitions. The proposed safe-RL-based driving policy improves the vehicle’s safe driving ability using a Q-table that stores the values corresponding to each action state. Moreover, owing to the trade-off between the ε-greedy values and safe distance threshold, the simulation results demonstrate the superior performance of the proposed approach compared to other alternative RL approaches, such as the ε-greedy Q-learning (GQL) and decaying ε-greedy Q-learning (DGQL), in an uncertain traffic environment. This study’s contributions are twofold: it improves the autonomous vehicle’s exploration-exploitation and safe driving ability while utilizing the advantages of FSM when surrounding cars are inside safe-driving zones, and it analyzes the impact of safe-RL parameters in exploring the environment safely.