• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.217-223
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• 2012

Time synchronization problems is very important in everyday life and a variety of industries, In this paper, we developed PLB(Power Line Broadcasting) system which broadcast time information to each device through power line modems. In our system, the smartphone synchronized to GPS time is used as a time source and we propose, develop and evaluate a relay system to solve the difficulties of long-distance transmission of power line modem technology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1004-1009
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• 2004

Precise time synchronization is a main technology in high-speed communications, parallel and distributed processing systems, Internet information industry and electronic commerce. Synchronized clocks are useful for many leasers. Often a distributed system is designed to realize some synchronized behavior, especially in real-time processing in factories, aircraft, space vehicles, and military applications. Nowadays, time synchronization has been compulsory thing as distributed processing and network operations are generalized. A network time server obtains, keeps accurate and precise time by synchronizing its local clock to standard reference time source and distributes time information through standard time synchronization protocol. This paper describes design issues and implementation of a network time server for time synchronization especially based on a clock model. The system uses GPS (Global Positioning System) as a standard reference time source and offers UTC (universal Time coordinated) through NTP (Network Time protocol). Implementation result and performance analysis are also presented.

• Journal of the Korean Society for Library and Information Science
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• v.36 no.4
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• pp.175-205
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• 2002

Information visualization in information retrieval is a creating tool that enables us to observe, manipulate, search, navigate, explore, filter, discover, understand, interact with large volumes of data for more rapidly and far more effectively to discover hidden patterns. The focus of this study is to investigate and analyze information visualization techniques in information retrieval system in the three-schematic levels. In result, it was found that first, scientific data, documents, and retrieval result information are visualized through various techniques. Second, information visualization techniques which facilitate navigation and interaction are zoom and pan, focus+context techniques, incremental exploration, and clustering. Third, the visual metaphors used by the visualization systems are presented in the linear structure, hierarchy structure, network structure, and vector scatter structure.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.452-458
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• 2013

In this paper, we propose the method for automatically transfers images into tactile maps information based on cognition characteristics of visually impaired persons to more easily provide various image information for visually impaired persons. The proposed method automatically classify color images into row complexity and high complexity based on intensity information and transfer images into tactile map information using each different transformation process. Experimental evaluation, We performed with visually impaired five persons experiments for evaluating the recognition and satisfaction that tactile maps of the proposed automatic transforming method and the manually generated tactile maps of braille textbooks. Experimental results, the recognition and satisfaction that the tactile maps of the proposed method generated are very similar to those of the tactile maps of braille textbooks. Therefore, it could hugely be reduced the time and money of production education materials, and it could greatly improved educative results because it can add more easily that many image data of education materials.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1619-1627
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• 2014

Wearable computer systems can use the wireless universal serial bus (WUSB) that refers to USB technology that is merged with WiMedia PHY/MAC technical specifications. In this paper, we focus on an integrated system of the wireless USB over the IEEE 802.15.6 wireless body area networks (WBAN) for wireless wearable computer systems supporting U-health services. And a communication structure that performs the time-synchronization is proposed for WUSB over IEEE 802.15.6 hierarchical protocol. Proposed time-synchronization mechanisms adopt the WBAN Polling Access and combine it with a time-synchronization middleware using time stamps. In our performance evaluations, time-synchronization performances with only WBAN Polling Access scheme are analyzed first. After that, performances combined with the time-synchronization middleware are analyzed to evaluate the effectiveness of proposed time-synchronization structure in WUSB over IEEE 802.15.6.

• Journal of the Korean Chemical Society
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• v.67 no.5
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• pp.353-361
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• 2023

This study analyzed the uses of visual representations of particles in the matter units of the middle school science textbooks developed under the 2015 Revised National Curriculum. The material units in four textbooks were divided into explanation, inquiry, and evaluation sections, and visual representations of particles presented in the science textbooks were analyzed by the use type, the activity type, and the level of activity. In the explanation section, the visual representations of particles were mainly presented in the auxiliary use type, and in the inquiry and evaluation section, they were mainly presented in a direct use type. In terms of the activity types of the direct use of visual representations of particles, the interpreting activity was mainly presented in the explanation and evaluation sections, while the generating activity and completing activity were presented in relatively higher proportion in the inquiry section than the other two sections. In terms of activity level, identifying was the most common activity level in the explanation section, and inferring was the most common activity level in the inquiry and evaluation sections. Based on these results, the implications for the presentation and uses of visual representations of particles in science textbooks are discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.68-69
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• 2007

논문은 항만 위험관리의 한 분야로 항로를 계획하거나 기존 항로를 검증하는데 필요한 조선자의 조종상의 곤란한 정도를 다루기 위한 것이다. 이 논문은 한국해양연수원이 보유하고 있는 실시간 풀미션 선박조종 시뮬레이터를 이용하여 부산 북항의 방파제 통과시에 나타나는 조선자의 주관적 평가와 조선자가 시행한 조종 위험도에 대한 상관관계를 비교하였으며 조선자의 심리적 부담감이 실제 조선에 어떻게 나타나는가를 중점적으로 다르고 있다. 이 논문의 결론은 두 가지로 말할 수 있는데 하냐는 조종위험도와 주관적 평가 사이에는 상관관계가 있어 조종위험도가 크면 주관적 평가도 같이 증가함을 알 수 있고 다른 하나는 충분히 'tideway'를 주면 통과할 수 있는데도 불구하고 시각적으로 보이는 여유 공간에 제한을 받아 통과할 정도의 'tideway'를 줄 수 없는 점이다. 이를 보면 시각적으로 보이는 모습이 항로 설계에 중요한 부분이 됨을 알 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.1122-1125
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• 2020

AI의 결과를 이해하기 위해서 XAI(eXplainable Artificial Intelligence)의 연구는 매우 중요하다. 세계적으로 XAI 개발 연구는 많이 진행되고 있지만 개발된 XAI를 평가하는 연구는 매우 적다. 본 논문은 사용성 측면에서 XAI를 평가하기 위해 AI 사용성 요소, 과학적 설명의 요소, 휴리스틱 평가 요소를 분류하고 의사결정 나무를 시각화여 심미도를 평가한다.

• Journal of Navigation and Port Research
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• v.47 no.1
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• pp.10-17
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• 2023

A series of studies on the development of autonomous surface ships have been promoted in domestic and foreign countries. One of the main technologies for the development of autonomous ships is path-following control, which is closely related to securing the safety of ships at sea. In this regard, the path-following performance of an autonomous ship should be first evaluated at the design stage. The main aim of this study was to develop a visual and quantitative evaluation method for the path-following control performance of an autonomous ship at the design stage. This evaluation technique was developed using a computational fluid dynamics (CFD)-based path-following control model together with a line-of-sight (LOS) guidance algorithm. CFD software was utilized to visualize waves around the ship, performing path-following control for visual evaluation. In addition, a quantitative evaluation was carried out using the difference between the desired and estimated yaw angles, as well as the distance difference between the planned and estimated trajectories. The results demonstrated that the ship experienced large deviations from the planned path near the waypoints while changing its course. It was also found that the fluid phenomena around the ship could be easily identified by visualizing the flow generated by the ship. It is expected that the evaluation method proposed in this study will contribute to the visual and quantitative evaluation of the path-following performance of autonomous ships at the design stage.

• Korean Journal of Environment and Ecology
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• v.9 no.2
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• pp.232-249
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• 1996

The purpose of this is to suggest objective basic data for the use development and conservation management of the national park through the quantitative analysis of the visual quality included in the physical environment of the Odaesan National Park, for this, spatial images structure of physical elements have been analyzed by factor analysis algorithm and degree of visual quality have been measured mainly by questionnaries. Result of this thesis can be summarized as follows. Factors covering the spatial image of the Odaesan National Park landscape have been found to be the pverall synthetic evaluation, physical, spatial, natural quality and, appeal factors such as the overall the synthetic evaluation, spatial and appeal yield high factor scores. As for the factors determining the degree of visual quality of clear of valley, peculiarity of configuration, natural of trail, harmony of suitable artificaial planting and temple.