• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.230-231
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• 2018

Recently, the danger for radioactive materials has become a hot topic. Beginning with the Chernobyl nuclear accident in 1996, in 2011, the Fukushima nuclear power plant in Japan suffered major damage such as large-scale casualties and radioactive dangerous area selection. Concerns about leakage of radioactive materials due to recent earthquakes have been deepening in Korea, such as Wolsong Nuclear Power Plant in Gyeongju, and there is a growing interest in the safety of radioactive materials through the media and the media. However, the route to exposure to radioactive materials is not limited to these large-scale nuclear accidents. Typical examples of this are radioactive substances exposed in daily life. In the case of radon gas, the danger is being revealed through current events programs and news, and natural radiation exposure is attracting attention.

• KSBB Journal
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• v.9 no.3
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• pp.306-311
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• 1994

Optical resolution of racemic ${\alpha}$-methylbenzylamine was carried out by using Bacillus licheniformis protease in organic media. Enantioselective amidation of racemic amino with an ester as an acyl donor was successfully employed to resolve the racemate. To enhance reaction rate and enantioselectivity, pH-adjustment by lyophilization of enzyme dissolved in buffer, colyophilization with salts or lyoprotectants, selection of solvents and molecular design of esters were investigated. The optimization of the resolution reaction achieved about 30-fold increase in initial reaction rate and about 12-fold increase in enantioselectivity, respectively.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.2
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• pp.61-69
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• 2015

Undifferentiated stem cells are being studied to obtain information on the therapeutic potential of isolates that are produced. Dental Pulp Stem Ccell (DPSC) may provide an abundant supply of highly proliferative, multipotent Mesenchymal Stem Cells (MSC), which are now known to be capable of regenerating a variety of human tissues including bone and other dental structures. Many factors influence DPSC quality and quantity, including the specific methods used to isolate, collect, concentrate, and store these isolates once they are removed. Ancillary factors, such as the choice of media, the selection of early versus late passage cells, and cryopreservation techniques may also influence the differentiation potential and proliferative capacity of DPSC isolates. This literature review concludes that due to the delicate nature of DPSC, more research is needed for dental researchers and clinicians to more fully explore the feasibility and potential for isolating and culturing DPSCs extracted from adult human teeth in order to provide more accurate and informed advice for this newly developing field of regenerative medicine.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.1021-1023
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• 2012

본 논문에서는 UWB 기술 기반 WiMedia Distributed Medium Access Control (D-MAC) 표준 프로토콜에 적용할 수 있는 Satisfaction of QoS (SoQ) 기반 협력 통신 프로토콜을 제안한다. 이를 위해 UWB 링크 전송 속도와 QoS 척도에 따른 릴레이 노드 선정 알고리즘을 제안한다. 본 논문에서 제안하는 SoQ 기반 협력 통신 프로토콜은 분산적인 D-MAC 표준 기술과 호환성을 갖고, 각 디바이스에서 독립적으로 실행되는 SoQ 기반 Relay Node Selection (RNS) 기준에 따라 실행된다.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.500-519
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• 2019

The blooming of social media has simulated interest in sentiment analysis. Sentiment analysis aims to determine from a specific piece of content the overall attitude of its author in relation to a specific item, product, brand, or service. In sentiment analysis, the focus is on the subjective sentences. Hence, in order to discover and extract the subjective information from a given text, researchers have applied various methods in computational linguistics, natural language processing, and text analysis. The aim of this paper is to provide an in-depth up-to-date study of the sentiment analysis algorithms in order to familiarize with other works done in the subject. The paper focuses on the main tasks and applications of sentiment analysis. State-of-the-art algorithms, methodologies and techniques have been categorized and summarized to facilitate future research in this field.

• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.81-94
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• 2020

This study developed evaluation indicators for the comfort experience of virtual reality (VR) headsets by classifying, defining, and weighting cybersickness-causing factors using the Delphi research method and analytic hierarchical process (AHP) approach. Four surveys were conducted with 20 experts on VR motion sickness. The expert surveys involved the 1) classification and definition of cybersickness-causing dimensions, classification of sub-factors for each dimension, and selection of evaluation indicators, 2) self-reassessment of the results of each step, 3) validity revaluation, and 4) final weighting calculation. Based on the surveys, the evaluation indicators for the comfort experience of VR headsets were classified into eight sub-factors: field of view (FoV)-device FoV, latency-device latency, framerate-device framerate, V-sync-device V-sync, rig-camera angle view, rig-no-parallax point, resolution-device resolution, and resolution-pixels per inch (PPI). A total of six dimensions and eight sub-factors were identified; sub-factor-based evaluation indicators were also developed.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.436-446
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• 2024

This study contemplates the effect of social media advertising attributes on consumers' purchasing decisions in cosmetic products. It will serve as basic data for SNS's advertising strategy and marketing that promotes cosmetics sales. This study conducted a survey and went through the analysis process of SPSS v.25.0 statistical program. Frequency analysis, exploratory factor analysis, descriptive statistical analysis, correlation analysis, and regression analysis were conducted to analyze that informativity, reliability, entertainment, interactivity, and disturbance among SNS advertising attributes were used as effective advertising strategies, which had a positive effect on consumers' purchasing decisions. Therefore, in the cosmetics industry, it is necessary to seek strategies to actively utilize marketing in the social media space to promote consumers' purchase needs and to activate purchases.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.32-35
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• 2015

국내에서 디지털라디오를 위한 연구와 실험 및 전송방식 선정 시도가 1997년부터 본격적으로 시도되었다. 그동안 국내에서 검토된 디지털라디오 전송방식은 DAB, DAB+, HD-Radio, DRM, DRM+ 방식에 대한 연구가 이루어졌고, 비교실험도 실행되었다. 그러나 각각의 전송방식에 대한 방송사마다 선호도가 다르고, 주파수 할당 문제를 포함하여 정부와 방송사의 이해와 득실에 대한 해석 방향이 많이 다르기 때문에 아직도 국내 전송방식을 결정하기가 매우 어려운 실정이다. 이에 본 논문은 먼저 아날로그 라디오방송과 디지털 라디오방송이 공통적으로 가지고 있어야 하는 중요한 목표와 목적 몇 가지를 선정하여 연구문제로 설정하였다. 연구방법으로는 현재 아날로그 FM방송과 동일한 내용이 동시에 전송되고 있는 DMB의 라디오 채널을 대상으로 FM방송과 수신환경을 비교 조사를 해보고, 주어진 연구문제를 충족할 수 있는 요소를 얼마나 가지고 있는지 분석을 해보았다. 나머지 전송방식에 대해서는 DMB에 포함된 DAB방식의 디지털라디오 규격과 2011년 ETRI 비교실험 결과 자료를 기준으로 상대적 비교를 통하여 긍정적 요소와 부정적 요소를 분석 헤 봄으로써 향후 디지털라디오 수신환경 구축 목표와 전송방식 선정에 실질적인 도움이 될 수 있는 방안을 제시하고자 한다.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.4
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• pp.223-230
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• 1997

DRASTIC system developed by U.S.EPA, is widely used for assessing regional groundwater pollution susceptibility by using hydrogeological factors such as depth to water, net recharge, aquifer media, soil media, topography, vadose zone media, hydraulic conductivity. The system can be applied to site selection of well or waste disposal and landuse for groundwater protection. In this study, hydrogeological spatial database of Younggwang area about topography, drainage, well, geology, soil and landuse was constructed using GIS (Geographic Information System) and regional groundwater pollution susceptibility is analyzed using the spatial database and GIS overlay technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3121-3135
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• 2015

Owing to the increase in consumption of multimedia content and the improvement of device capacity, user demand for high-quality content has increased. However, it is difficult to transport such large amounts of content over the existing broadcasting network with limited bandwidth. To provide high-definition broadcasting, some studies suggest methods of transporting multimedia over heterogeneous networks after encoding content hierarchically. MPEG Media Transport (MMT), standardized by Moving Picture Experts Group (MPEG), is a solution that enables large-volume media transport over heterogeneous networks such as digital broadcasting networks and packet-switched networks. In the case of delivering a scalable encoded video over different networks, synchronization of each stream is an important issue. MMT defines a synchronization scheme, but does not contain sufficient functions to implement it. In this paper, we propose a synchronization scheme for media streams that are encoded hierarchically, divided into layers, and transported over heterogeneous networks. We implement our scheme using MMT and HTTP, and experimented using three encapsulated video streams with different durations. As a result, we show that the proposed scheme can reduce the waiting time to display high-quality video, relative to Dynamic Adaptive Streaming over HTTP-Scalable Video Coding (DASH-SVC) by requesting segments of enhanced layers after calculating the transmission time. Additionally, we find out that the selection of durations have a relation to the characteristics of the video.