• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1105-1112
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• 2022

Field data monitoring systems such as renewable energy generation and smart farm integrated control are developing from PC and server to mobile first, and various wireless communication and application services have emerged with the development of IoT technology. Low-power wide-area networks are services optimized for low-power, low-capacity, and low-speed data transmission, and data collected in the field is transmitted to designated storage servers or cloud-based data platforms, enabling data monitoring. In this paper, we implement an IoT repeater that collects field data with a single device and transmits it to a wireless carrier cloud data flat using a low-power wide-area network, and a monitoring app using it. Using this, the system configuration is simpler, the cost of deployment and operation is lower, and effective data accumulation is possible.

• Journal of Korea Multimedia Society
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• v.25 no.8
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• pp.1188-1202
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• 2022

This study aims to investigate what communication phenomenon social viewing is associated with, and how satisfaction with using live commerce affects, taking into account that live commerce is a form of content consumption based on social viewing. In particular, social viewing is classified in this study as message production and sharing activities that influence users' satisfaction with live commerce viewing, as well as how two-dimensional social viewing behaviors are associated with users' perception of social presence. Then, the impact of these factors on improving viewing satisfaction is determined. It is also designed to investigate the moderating effect of social presence and viewing satisfaction as a function of the size of users' social networks by taking into account how social viewing affects the degree of social exchange among users. The findings of the analysis are as follows. First, social viewing behaviors. i.e., sharing and production behavior were identified as strong factors that have a direct impact on social presence and viewing satisfaction. Second, social presence plays a moderating role in the relationship between social viewing behavior and viewing satisfaction. Third, the impact of sharing behavior on social presence and viewing satisfaction was greater than the that of production behavior. Fourth, network size (number of followers and followings) had no direct effect on social reality or viewing satisfaction, but it had a moderating effect on the relationship between production behavior and social presence. Based on the findings, the implications and recommendations were discussed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.313-316
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• 2021

In the IoT(IoT: Internet of Things) environment, network configuration is essential to collect data generated from objects. Various communication methods are used to process data of objects, and wireless communication methods such as Bluetooth and WiFi are mainly used. In order to collect data of objects, a communication module must be installed to collect data generated from sensors or edge devices in real time. And in order to deliver data to the database, a software architecture must be configured. Data generated from objects can be stored and managed in a database in real time, and data necessary for industrial safety can be extracted and utilized for industrial safety service applications. In this paper, a network environment was constructed using a LoRa(LoRa: Long Range) gateway to collect object data, and a client/server data collection model was designed to collect object data transmitted from the LoRa module. In order to secure the resources necessary for data collection and storage management without data leakage, data collection should be possible in real time. As an application service, location data required for industrial safety can be stored and managed in a database in real time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.33-39
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• 2023

Recently, reinforcement learning has been used to improve the communication performance of flying ad-hoc networks (FANETs) and to design mobility models. Mobility model is a key factor for predicting and controlling the movement of unmmaned aerial vehicle (UAVs). In this paper, we designed and analyzed the performance of Q-learning with fourier basis function approximation and Deep-Q Network (DQN) models for optimal path finding in a three-dimensional virtual environment where UAVs operate. The experimental results show that the DQN model is more suitable for optimal path finding than the Q-learning model in a three-dimensional virtual environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.1-6
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• 2024

In this paper, we designed and implemented the security network NVR system that can flexibly use the internal network and VPN network. In general, the NVR systems that only use internal networks cannot be access from the outside, which has the disadvantage of unnecessary inspections and inability to access from the outside. External access has made possible using the VPN security network, and a NVR system software was designed and implemented so that the existing internal network could be used. We compared with the NVR system usage environment in the internal network through the client and the NVR system. It also has implemented usage environment with the VPN network through the mobile APP, and confirmed that the same NVR was operating normally with the same functions. We also studied on IP based NVR for flexible access with closed loop network based on VPN system.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.5
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• pp.835-844
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• 2024

The rapid expansion of the real-time streaming industry is driven by the widespread adoption of portable devices and the growth of video platforms. Consequently, the demand for transmitting and receiving large volumes of content has increased, leading to traffic congestion and inefficiency in traditional IP address-based networks. To address these issues, Contents Centric Networking (CCN) is being researched as an alternative. CCN is a network architecture based on content names (what) rather than IP addresses (where), where each node has a cache space called Content Store (CS) to alleviate server bottlenecks and traffic congestion. However, in a CCN environment, the departure of intermediate nodes between clients and servers can lead to packet loss and degradation of service quality. Therefore, research on managing the departure of intermediate nodes in real-time environments is essential. This study proposes a new method for detecting the departure of intermediate nodes through RSSI (Received Signal Strength Indicator) monitoring and for efficiently creating backup paths.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.6
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• pp.39-47
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• 2012

As a scheme to efficiently reduce the effects of multipath fading in next generation wireless communication systems, cooperative communication systems have recently come into the spotlight. Since these cooperative communication systems use cooperative relays with diverse fading coefficients to transmit information, having all relays participate in cooperative communication may result in unnecessary waste of resources, and thus relay selection schemes are required to efficiently use wireless resources. In this paper, we propose an efficient relay selection scheme through self-learning in cooperative wireless networks using Q-learning algorithm. In this scheme, we define states, actions and two rewards to achieve good SER (Symbol Error Rate) performance, while selecting a small number of cooperative relays. When these parameters are well-defined, we can obtain good performance. For demonstrating the superiority of the proposed Q-learning, We compared the proposed scheme with Q-learning and a relay selection scheme with a mathematical analysis. The simulation results show that, compared to a scheme that obtains optimum relays through a mathematical analysis, the proposed scheme uses resources efficiently by using smaller numbers of relays with comparable SER performance. According to these simulation results, the proposed scheme can be considered as a good attempt for future wireless communication.

• Journal of the Korean Society of Food Culture
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• v.27 no.6
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• pp.666-676
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• 2012

The purpose of this study was to propose effective marketing communication strategies for overseas Korean restaurants through a multilateral comparison analysis of American, Chinese, and Japanese consumers' attitudes towards communication media and Korean restaurants. The survey was written in English, Chinese, and Japanese, with guideline for surveyors, and conducted using both online and offline methods. Samples were collected from five major cities - Los Angeles, New York, Tokyo, Beijing and Shanghai, which are the foothold for the globalization of Korean food. When it comes to attitudes towards communication media, word-of-mouth showed a high mean value, indicating it as the most useful and reliable media recognized by consumers who visited Korean restaurants. Furthermore, the necessity of recognizing the importance of visual communication in the physical environment of Korean restaurants and specialized websites, featuring restaurants and gourmet food, was observed. Consumers in all three nations chose word-of-mouth as the most useful and reliable media for learning about Korean restaurants. In addition, American consumers highly depended on signage and restaurant exteriors. Chinese consumers highly recognized the usefulness and reliability of offline media, such as newspapers, magazines, and events, while Japanese consumers considered online media, such as gourmet websites, blogs and social networks, as useful and reliable sources. A significantly positive attitude and high value was observed in all who had visited Korean restaurants. American and Japanese consumers had a significantly higher rate of intention to visit Korean restaurants in the future and to tell others about their satisfaction with Korean restaurants. Meanwhile, the average rate of prior preference for Korean restaurants (when choosing restaurants) was the lowest in all three countries. This study is useful for both the Korean government and food enterprises abroad to plan and develop marketing communication strategies properly for overseas Korean restaurants.

• Journal of Navigation and Port Research
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• v.37 no.3
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• pp.275-281
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• 2013

Ship Standard Network was submitted as a common subject of e-navigation by 81th IMO MSC 2005. This agenda was given an official status with strategy planning of e-navigation for Ship Standard Network after approval of WG program of 81th MSC 2006. Nowadays approximately 400 heterogeneous navigation and communication equipments are working on ships at sea. Standardization of ship network is to support exchanging various data efficiently. Among them, 4S network is defined as a wireless communication network between ship to ship and ship to shore which provides unceasing communication channel ship to shore. It has been expected to trigger various services and applications based on 4S network. However, no technologies and products has been appeared at fields yet. but now there's not specific technologies and developing products. In this paper, We developed a 4S multiple media switching server and a ship-land information exchange system to overcome the heterogeneity and provide efficient communication environments.. The performance of the implemented system was verified by TTA(Telecommunications Technology Association) V&V(Verification and Validation).

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.679-685
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• 2018

In order to reduce marine accidents using advanced information and communication technology, various research and development projects are conducted globally on e-Navigation related technologies and services. Existing studies do not provide policy measures for LTE-M. In order for these technologies and services to be installed on vessels and to contribute to the prevention of accidents at sea, the law should be expand operational organizations and systems. In particular, communication equipment and related technical standards should be prepared, and its digital communication technology (LTE-M, VDES, Digital-MF / HF, etc.) In this study, we conducted short, medium, and long term performance assessment of the identification system and the policy for effective implementation of Korean e-Navigation. We presented a visible plan of the relevant policy. For example, e-Navigation core services, e-Navigation communication networks and operating systems, e-Navigation international standard leading technologies and e-navigation services activated in the field. To do this, we conducted research based on the progress data of the Korean e-Navigation project, which was led by the Ministry of Maritime Affairs and Fisheries, and conducted research discussions with practitioners and experts in related fields. As a result of this study, it is expected that the proposed policies will contribute to the reduction of marine accidents, the promotion of the maritime industry and the development of additional government policies for national security.