• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.724-729
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• 2008

This paper presents the calculation of the required bandwidth of common frequency bandwidth applying queueing theory for maximizing the efficiency of frequency resource of WPAN(Wireless Personal Area Network) based Digital acoustic and communication devices. It assumed that LBT device(ZigBee) and FH devices (DCP, RFID and Bluetooth) coexist in the common frequency band for WPAN based Digital acoustic and communication devices. Frequency hopping (FH) and listen before talk (LBT) have been used for interference avoidance in the short range device (SRD). The LBT system transmits data after searching for usable frequency bandwidth in the radio wave environment. However, the FH system transmits data without searching for usable frequency bandwidth. The queuing theory is employed to model the FH and LBT system, respectively. As a result, the throughput for each channel was analyzed by processing the usage frequency and the interval of service time for each channel statistically. When common frequency bandwidth is shared with SRD using 250mW, it was known that about 35 channels were required at the condition of throughput 84%, which was determined with the input condition of Gaussian distribution implying safety communication. Therefore, the common frequency bandwidth is estimated with multiplying the number of channel by the bandwidth per channel. These methodology will be useful for the efficient usage of frequency bandwidth.

• Korean journal of communication and information
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• v.20
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• pp.111-139
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• 2003

This study aims to explore concepts of public interest and universal service which have been essential ideologies and policy goals, but which have been a the state of conceptual chaos so far. It sheds light upon three aspects : (1) the origins of public interest and universal service, (2) conceptual components of public interest and universal service, and (3) the implementation of public interest and universal service ideologies into policy. As a result of this analysis, it was found, firstly, that public interest of broadcasting originated from western countries, was rooted in the United States, and then spread all over the world later. After universal service was begun in the United States, it became a key ideology of information and telecommunication in European countries and other countries as well. Secondly, when examining the conceptual components, more differences were found than commonalities between these two concepts. The most conspicuous common point was universalism The concept of public interest includes not only universal service, but also connotes other components such as independence, diversity, quality, and locality which are related to content. Thirdly, when these two ideologies are implemented into policy, there Is a contrast. This study shows that the public interest ideology was realized into regulatory policies, while the universal service ideology was realized into supportive policies. In conclusion, this paper suggests more exact usage academically, showing the differences between the two concepts. This paper recommends an enforced legal duty of broadcasters to provide universal service when the current broadcasting law is revised.

• Journal of Advanced Navigation Technology
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• v.20 no.2
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• pp.116-126
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• 2016

In this study, has designed the ship application system for efficient data integration management of onboard ship and shore application/service utilizing data collected onboard ship, and has implemented the module. In order to supports onboard ship and shore service utilizing onboard ship collected data and provide a easy to access among individual devices, the ship application system applied the XML structure of ISO 16425 and the data sharing system model discussed in IALA, and the common module for system operation, a windows service for data collection/integral management, and web service module for management has been implemented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.99-105
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• 2021

In addition to the OTT video production service represented by Nexflix and YouTube, a personalized recommendation system for content with artificial intelligence has become common. YouTube's personalized recommendation service system consists of two neural networks, one neural network consisting of a recommendation candidate generation model and the other consisting of a ranking network. Netflix's video recommendation system consists of two data classification systems, divided into content-based filtering and collaborative filtering. As the online platform-led content production is activated by the Corona Pandemic, the field of virtual influencers using artificial intelligence is emerging. Virtual influencers are produced with GAN (Generative Adversarial Networks) artificial intelligence, and are unsupervised learning algorithms in which two opposing systems compete with each other. This study also researched the possibility of developing AI platform based on individual recommendation and virtual influencer (metabus) as a core content of OTT in the future.

• ETRI Journal
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• v.35 no.6
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• pp.1058-1067
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• 2013

An approach for game bot detection in massively multiplayer online role-playing games (MMORPGs) based on the analysis of game playing behavior is proposed. Since MMORPGs are large-scale games, users can play in various ways. This variety in playing behavior makes it hard to detect game bots based on play behaviors. To cope with this problem, the proposed approach observes game playing behaviors of users and groups them by their behavioral similarities. Then, it develops a local bot detection model for each player group. Since the locally optimized models can more accurately detect game bots within each player group, the combination of those models brings about overall improvement. Behavioral features are selected and developed to accurately detect game bots with the low resolution data, considering common aspects of MMORPG playing. Through the experiment with the real data from a game currently in service, it is shown that the proposed local model approach yields more accurate results.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.31-42
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• 2019

As smartphone H/W performance and mobile communication service have been enhanced, large-capacity 3D modeling files are available in smartphones. Common formats of 3D modeling files include STL (STereoLithography), OBJ (Wavefront file format specification), FBX (Filmbox), and glTF (open GL Transmission Format). Each format has different characteristics depending on the configuration and functions, and formats that are supported are varied depending on the applications. Large-size files are commonly used. The 4th generation mobile communication network secures loading of 3D modeling files and transmission of large-size geometric files in order to provide augmented reality services via smartphones. This paper explains the concepts and characteristics of major 3D file formats such as OBJ, FBX, and glTF. In addition, it compares their performance in a wired web with that in the 4th generation mobile communication network. The loading time and packet transmission in each 3D format are also measured by means of different mobile web browsers (Google Chrome and MS Edge). The experiment result shows that glTF demonstrated the most efficient performance while the loading time of OBJ was relatively excessive. Findings of this study can be utilized in selecting specific 3D file formats for rendering time reduction depending on the mobile web environments.

• Journal of Service Research and Studies
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• v.9 no.1
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• pp.73-86
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• 2019

This study discusses the 4th industrial revolution and technology commercialization (TC), identifies success factor (SFs) for TC from the literature review, and empirically tests these factors through questionnaires to executives in the 4th industrial revolution industries. Literature review identifies 11 SFs and they are communication, management support, incentives for TC, common goals, understanding business, awareness of TC, cooperation among partners, government support, concreteness of technology, demand-pull technology, and experience of TC. Questionnaires were administered to CEOs and CIOs in 202 companies in the 4th industrial revolution industries and final response rate was 64.4% (260 out of 404) that is considered to be high. Respondents rate cooperation among partners as the most important, followed by management support, communication, common goals, and incentives for TC. To successfully pursue technology commercialization projects in the 4th industrial revolution industries, the attention should be focused on SFs that are evaluated as very important.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4305-4323
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• 2014

In this paper, we investigate the degrees of freedom (DOF) of the Y channel consisting of three single-antenna users and a two-antenna common access relay, where each user intends to exchange independent messages with the other two users with the assistance of the relay. We show that the DOF of this particular scenario is 1.5. In order to prove this result, we firstly derive a DOF upper bound based on cut-set bound by allowing cooperation among users, which shows that the total DOF is upper bounded by 1.5. Then we propose a novel transmission scheme based on asymmetric signal space alignment (ASSA) to demonstrate the achievability of the upper bound. Theoretical evaluation and numerical results confirm that the upper bound can be achieved by utilizing ASSA, which also proves the optimality of the ASSA-based scheme in terms of DOF. Combining the upper bound and achievability, we conclude that the exact DOF is 1.5. Moreover, we present a novel iterative joint beamforming optimization (I-JBO) algorithm to further improve the sum rate. Numerical simulations have been provided to demonstrate the convergence speed and performance advantage of the I-JBO algorithm.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.131-134
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• 2005

Recently, RF systems have rapidly grown with the extension of the mobile communication service The mobile service companies are providing the satellite broadcasting and common usage are expected. Coinciding with current trend, the development of improved satellite DMB (Digital Multimedia Broadcasting) tuner is required. To improve the receiving sensitivity under the poor communication circumstance, It is necessary to design the LNA (Low Noise Amplifier) with outstanding low noise characteristic and the BPF (Bandpass Filter) to transmit only desired signal without distortion and loss. Besides high reliability, the miniaturization and lightweight are required for design of mobile terminals. In this study, we designed and fabricated DMB SIR-type BPF which operates at 2642 MHz and is embedded in the substrate using LTCC. As a result, we obtained the passband insertion loss of 2.4 dB and the passband ripple of 0.08 dB. So this DMB SIR-type BPF is applicable to RF module of a satellite DMB tuner.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.853-871
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• 2012

The location based service is divided into GPS that uses the artificial satellite or base transceiver station in order to cover the wide area and RTLS(Real Time Location System) using the Zigbee, RFID, CSS(Chirp Spread Spectrum), UWB, Bluetooth and Wi-Fi equipment in the space(close range) limited like the building inside or park. Moreover it also repeats the technical development upon through the acceleration of the development of the wire and wireless infrastructure and determination technology, the development of the Internet, diversification of the contents, and etc. As a result, it is expected to develop around the determination technology, witch is common core technology element, contents technology, Internet and mobile communication technology, and etc. afterward. In this research, the direction we investigate was to find and analyze new technology and standardization trend of LBS in order to contribute to the related industry.