• Journal of the Korea Society of Computer and Information
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• v.21 no.2
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• pp.43-49
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• 2016

In this paper, we propose the controllability function and service design to efficiently implement the control of the disaster communication network, using Internet of Things(IoT) Technology. In accordance with the spread of Information Communication Technology(ICT), the era for building a disaster communications system without exclusion over the entire areas has emerged. National wireless mesh networks for public safety and disaster relief have been evolving to strengthen the pre-disaster response system using the latest technologies through the convergence of various technologies and services from the viewpoint of the command and control between disaster response agencies. In line with such a technological paradigm shift, the controllability of the objects in the IoT has been emerging as a key quality requirement of a disaster communications system. In this study, the objects are classified by the subject of control according to the IoT component, such as data, network resources and services in order to effectively implement their controllability. In addition, based on the destination of this controllability, technologies and services have been designed that can reduce the damage caused by disasters. Technologies and services that were derived from this study must be implemented in the current disaster safety network systems together with the establishment of an infrastructure for the networks in order that all persons are able to effectively utilize the disaster communications system for their safety.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.6
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• pp.826-841
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• 2018

The military satellite communication of ROK military, ANASIS is designed for analog data such as voice and streaming data. ANASIS cannot fully support ALL-IP communications due to its long propagation delay. The next generation satellite communication system is being designed to overcome the limitation. Next generation satellite communications system considers both high-speed and low-speed networks to support various operating environment. The low-speed satellite supports both broadband and narrow-band communication. This network works as the infrastructure for of wide-area internetworking over multiple AS's in the terrestrial network. It requires minimum satellite frequency and minimum power and works without PEP and router. In this paper, we propose a network operation structure to enable the inter-operation between high and low-speed satellite networks. In addition, we propose a data link protocol for low speed satellite networks.

• Journal of Distribution Science
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• v.20 no.9
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• pp.61-71
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• 2022

Purpose: This study analyzes the effects of variables affecting e-satisfaction and e-loyalty in e-commerce. Research design, data, and methodology: A survey was conducted to 384 Indonesia online shopping mobile application users. The questionnaire construct was designed based on several independent variables, such as application attractiveness, application functionality, and customer service on e-satisfaction and e-loyalty. E-satisfaction was positioned as an intervening variable to determine the effect on e-loyalty. Results: Application attractiveness, application functionality, and customer service shown positive effect on e-satisfaction in online shopping mobile application. At the same time, e-satisfaction also affected e-loyalty significantly as referred in previous studies. However, application attractiveness, while showed positive effect on e-satisfaction, in contrary with previous study does not showed very significant effect. Conclusion: Application functionality significantly influences users satisfaction compared to application attractiveness. E-satisfaction mediates as a factor between visual design, information access, and transaction in online shopping mobile application, which stimulates user loyalty. The study findings' can be a reference for companies to create and maintain users' satisfaction and loyalty via different aspects of mobile application. Further research should be conducted on other field of study as the industry has different aspects that affects user loyalty.

• Journal of Integrative Natural Science
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• v.15 no.1
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• pp.37-48
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• 2022

Metabus, a three-dimensional virtual environment for digital communication, has gained a lot of attention recently. Even so, there are still many unanswered questions about the user's consciousness and behavior. A difference in nature from conventional digital communication is also unclear. This paper aims to study Metabus on a hypothetical premise by organizing the possibility of Metabus for communication activation based on a research project aimed at using Metabus to support the formation of a community of school dormitories and studio rental residents. After reviewing the establishment process and application cases of Metabus, we focus on the character (avatar) used as the user's alter ego within the metabus, which will allow customization of both form and content different from text-based communication. The "physicality" and the "spatiality" of the metaverse and the "immersion" they bring are among the most important, functional innovations. Based on this summary, a case of using metabuses will be reviewed to describe the research plan aimed at supporting community formation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.3
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• pp.779-800
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• 2024

Unmanned Aerial Vehicle (UAV) networks, also known as drone networks, have gained significant attention for their potential in various applications, including communication. UAV networks for communication involve using a fleet of drones to establish wireless connectivity and provide communication services in areas where traditional infrastructure is lacking or disrupted. UAV communication networks need to be highly secured to ensure the technology's security and the users' safety. The proposed survey provides a comprehensive overview of the current state-of-the-art UAV network security solutions. In this paper, we analyze the existing literature on UAV security and identify the various types of attacks and the underlying vulnerabilities they exploit. Detailed mitigation techniques and countermeasures for the protection of UAVs are described in this paper. The survey focuses on the implementation of novel technologies like Q-learning, blockchain, IRS, and mmWave. This paper discusses network simulation tools that range in complexity, features, and programming capabilities. Finally, future research directions and challenges are highlighted.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.1
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• pp.233-262
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• 2024

Due to the rapid evolution of vehicular ad hoc networks (VANETs), effective communication and security are now essential components in providing secure and reliable vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication. However, due to their dynamic nature and potential threats, VANETs need to have strong security mechanisms. This paper presents a novel approach to improve VANET security by combining the Vehicular Delay-Tolerant Network (VDTN) protocol with the Deep Reinforcement Learning (DRL) technique known as the Twin Delayed Deep Deterministic Policy Gradient (TD3) algorithm. A store-carry-forward method is used by the VDTN protocol to resolve the problems caused by inconsistent connectivity and disturbances in VANETs. The TD3 algorithm is employed for capturing and detecting Worm Hole Attack (WHA) behaviors in VANETs, thereby enhancing security measures. By combining these components, it is possible to create trustworthy and effective communication channels as well as successfully detect and stop rushing attacks inside the VANET. Extensive evaluations and simulations demonstrate the effectiveness of the proposed approach, enhancing both security and communication efficiency.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.6
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• pp.815-822
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• 2011

In this paper, a design and implemented of the data communication system on the entails inherent safety with the distress and urgency of maritime data communication services that are required for functional limitations of the existing mounting equipment and services to determine the likelihood MF/HF, VHF, Inmarsat satellite communication has a diversification of the GMDSS ship communication equipment. Proposed role and direction of the GMDSS on the communication media by the communication cost, throughput, communication speed and processing services available, communication range, etc. by conducting a performance analysis and evaluation in the future maritime communications environment.

• Journal of Korean Elementary Science Education
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• v.36 no.3
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• pp.256-272
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• 2017

The purpose of this research is to study and learn more features how this type of distribution for communication in $6^{th}$ grade first semester elementary science and mathematics according to communicative expression by 2009 revised curriculum. For this study, based on an analysis standard presented in previous research on the types of communication. The results of this research are as follows. First, because the mathematics presents the number of ways to communicate twice more than science, mathematics go through with much more problems to solve than science. Second, in mathematics, spoken method and written method have similar proportion, less in physical activity method. Third, Science showed balanced proportion among four areas; earth, life, energy, and material. On the other hand, mathematics only showed small numbers in the area of geometry but similar numbers in number and operations, regularity, measurement. Fourth, there is no common feature or relevance about communicative approach for convergence thinking in 2009 revised curriculum, it seems that it doesn't consider it as a revised.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.3012-3028
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• 2017

In this paper, we propose a joint power control strategy for both the uplink and downlink transmission by considering the energy requirements of the user equipments' uplink data transmissions in data and energy integrated communication networks (DEINs). In DEINs, the base station (BS) adopts the power splitting (PS) aided simultaneous wireless information and power transfer (SWIPT) technique in the downlink (DL) transmissions, while the user equipments (UEs) carry out their own uplink (UL) transmissions by exploiting the energy harvested during the BS's DL transmissions. In our DEIN model, there are M UEs served by the BS in order to fulfil both of their DL and UL transmissions. The orthogonal frequency division multiple access (OFDMA) technique is adopted for supporting the simultaneous transmissions of multiple UEs. Furthermore, a transmission frame is divided into N time slots in the medium access control (MAC) layer. The mathematical model is established for maximizing the sum-throughput of the UEs' DL transmissions and for ensuring their fairness during a single transmission frame T, respectively. In order to achieve these goals, in each transmission frame T, we optimally allocate the BS's power for each subcarrier and the PS factor for each UE during a specific time slot. The original optimisation problems are transformed into convex forms, which can be perfectly solved by convex optimisation theories. Our numerical results compare the optimal results by conceiving the objective of maximising the sum-throughput and those by conceiving the objective of maximising the fair-throughput. Furthermore, our numerical results also reveal the inherent tradeoff between the DL and the UL transmissions.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1206-1218
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• 2016

This article proposes a highly reliable power and communication system that guarantees the protection of essential instruments in a nuclear power plant under a severe accident. Both power and communication lines are established with not only conventional wired channels, but also the proposed wireless channels for emergency reserve. An inductive power transfer system is selected due to its robust power transfer characteristics under high temperature, high pressure, and highly humid environments with a large amount of scattered debris after a severe accident. A thermal insulation box and a glass-fiber reinforced plastic box are proposed to protect the essential instruments, including vulnerable electronic circuits, from extremely high temperatures of up to $627^{\circ}C$ and pressure of up to 5 bar. The proposed wireless power and communication system is experimentally verified by an inductive power transfer system prototype having a dipole coil structure and prototype Zigbee modules over a 7-m distance, where both the thermal insulation box and the glass-fiber reinforced plastic box are fabricated and tested using a high-temperature chamber. Moreover, an experiment on the effects of a high radiation environment on various electronic devices is conducted based on the radiation test having a maximum accumulated dose of 27 Mrad.