• Transactions on Electrical and Electronic Materials
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• 제18권3호
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• pp.151-154
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• 2017

In this article, we investigated the various influencing factors that degraded the lifetime of suspension insulators in 154 kV transmission lines, and showed the possible solutions to avoid such breakdowns. With respect to achieve safety, reliability and aesthetical considerations, the characteristics of transmission and distribution network power cables should be improved. Suspension insulators are particularly important to study, as they have developed to be the main component of transmission lines due to their ability to withstand the electrical conductivity of high-voltage power transmission. Suspension insulators are mostly made from glass, rubber and ceramic material due to their high resistivity. In Korea, porcelain suspension insulators are typically used in the transmission line system, as they are cheaper and more flexible compared to other types of insulators. This is effective from preventing very high and steep lightening impulse voltages from causing the breakdown of suspension insulators used in power lines. Other influential factors affect the lifetime of suspension insulators that we studied include temperature, water moisture, contamination, mechanical vibration and electrical stress.

• 한국IT서비스학회지
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• 제20권2호
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• pp.77-90
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• 2021

Online and mobile games represent digital entertainment. Not only the game grows fast, but also it has been noted for unique business models such as a subscription revenue model and free-to-play with partial payment. But, a recent revenue mechanism, called a loot-box system, has been criticized due to overspending, weak protection to teenagers, and more over gambling-like features. Policy makers and research communities have counted on expert opinions, review boards, and temporal survey studies to build countermeasures to minimize negative effects of online and mobile games. In this process, speed was not seriously considered. In this study, we attempt to use a big data source to find a way of observing a trend for policy makers and researchers. Specifically, we tried to apply the Word2Vec data mining algorithm to news repositories. From the findings, we acknowledged that the suggested design would be effective in lightening issues timely and precisely. This study contributes to digital entertainment service communities by providing a practical method to follow up trends; thus, helping practitioners have concrete grounds for balancing public concerns and business purposes.

• 기술혁신연구
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• 제26권2호
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• pp.69-93
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• 2018

기업들이 저원가와 높은 품질을 동시에 추구하게 됨에 따라 제품 아키텍처 기반 경쟁은 기업 전략의 중요한 일부가 되었다. 본 연구는 한 중 조선 산업(LNGC)분야 대표기업의 제품 아키텍처와 조직역량을 비교 분석하여 그들이 어떻게 혁신성과를 이루어 냈는지 고찰하였다. 그 결과, 한국기업은 동력계열의 연구개발에 있어 FGSS(Fuel gas supply system), PRS(Partial Re-liquefaction System)와 같이 에너지 효율을 개선하는 장치를 자체 개발하여 기존엔진에 추가하고, 선체 무게를 경량화 하는 등 다양한 미세조정 노력을 통해 우수한 성능을 가지게 하였다. 이는 우수한 연구조직 역량과 현장과의 긴밀한 협업을 통해 실현되었으며, 고부가가치선의 높은 매출로 이어질 수 있었다. 반면 중국 기업은 설계 및 연구개발의 편의성에 집중하여, 기존의 부품에 대한 미세조정 노력을 소홀히 했고 그 결과 동일한 부품을 사용하고도 한국의 선박에 비해 7-10% 낮은 연비 효율을 지닌 것으로 나타났다.

• 한국실내디자인학회논문집
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• 제19권4호
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• pp.90-98
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• 2010

This study intends to understand the change of the library's bookshelves shape, composition and arrangement based on the social-culture in each period. For this purpose, this study analyzes the morphological shift of the library's bookshelves and knowledge information focused on the history of western libraries from the ancient libraries to the modern public libraries before the 20th century. And the results are follows. 1) We can make sure that the changes of the library's bookshelves are based on the environmental factors like social cultural political factors and also understand that the knowledge information are developed based on the function which is decided by the needs of the times and the serious necessities of users. With this reason, the morphology and the function of the library's bookshelves have been changed. 2) The characters and meanings of the library's bookshelves are changed with the times from movable type to fixed type, from closing type to opening type, from privileged use to public use, from religious contents to general scientific contents. 3) The morphology of the library's bookshelves are shifted from cylindrical box to Chest type Press type and Lectern system, Stall system, Wall system and advanced to Mixed(Stall+Wall) system. 4) The construction and arrangement methods of the library's bookshelves are determined by the convenience and efficiency of the installation for the perusal environments as well as the regarding to the social-cultural factors. The arrangement criteria are determined by the security topics in the earlier stage, after that determined by the lightening topics and nowadays the access topics to the information. These analysis results are very useful to research the technology of the library's bookshelves to be changed continuously and also to forecast the morphology of the library's bookshelves can be planned in the spaces of the future libraries.

• 한국군사과학기술학회지
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• 제22권3호
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• pp.299-310
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• 2019

Increase of combat capability through the lightweighting of vehicles has been internationally issued. One of the methods for lightening is applying high hardness armor(HHA) steel which is outstanding ballistic performance and protection performance compared to weight. Development of HHA steel is currently completed in America, United Kingdom, Australia and Germany. It is used for not only combat vehicle, but also various combat device. Korea is developing new material of HHA steel according to this trend. When such HHA steel is applied to structure, welding process is used for connection of the structure. Cracks from hydrogen embrittlement and cold cracking are easily generated in welds of HHA steel and it greatly affects the strength of all structure. Decrease of strength from welding defect is critical to combat capability. Therefore, welding process optimization is important for performing the role of structure. In this study, international welding technology is reviewed through scientific research paper and patent.

• Journal of Biosystems Engineering
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• 제22권3호
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• pp.295-302
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• 1997

An ultimate purpose of this study was to develop an automatic system for brown rice quality inspection using image processing technique. In this study emphasis was put on developing an algorithm for discriminating the brown rice kernels depending on their external quality with a color image processing system equipped with an adaptor magnifying the input image and optical fiber for oblique lightening. Primarily, geometical and optical features of images were analyzed with paddy and the various brown rice kernel samples such as a sound, cracked, peen-transparent, green-opaque, colored, white-opaque and brokens. Secondary, geometrical and optical parameters significant for identifying each rice kernels were screened by a statistical analysis(STEPWISE and DISCRIM procedure, SAS wer. 6) and an algorithm fur on- line discrimination of the rice kernels in static state were developed, and finally its performance was evaluated. The results are summarized as follows. 1) It was ascertained that the cracked kernels can be detected when e incident angle of the oblique light is less than 2$0^{\circ}C$ but detectivity was significantly affected by the angle between the direction of the oblique light and the longitudinal axis of the rice kernel and also by the location of the embryo with respect to the oblique light. 2) The most significant Parameters which can discriminate brown rice kernels are area, length and R, B and r values among the several geometrical and optical parameters. 3) Discrimination accuracies of the algorithm were ranged from 90% to 96% for a sound, cracked, colored, broken and unhulled, about 81 % for green-transparent and white-opaque and 75 % for green-opaque, respectively.

• 한국산학기술학회논문지
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• 제18권6호
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• pp.21-28
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• 2017

농기계 상하차를 위한 전동 유압 슬라이딩 데크 시스템을 개발하는데 있어 경량화가 필수적이며, 이를 해결하기 위해 덤프 각도에 따른 슬라이딩 데크의 진출길이를 계산하고, 허용가능 각도 중 가강 큰 하중 받는 각도에서 재질과 두께를 변경하며 구조해석을 진행, 최적 두께와 재질을 선정하였다. 먼저 슬라이딩 데크 진출길이 계산식을 도출하기 위해 전체 시스템의 구성을 파악하고, 시스템을 단순화 하는 작업을 시행하였다. 또한 시스템의 입 출력 관계를 파악하기 위해 자유도 계산을 수행 하였고, 단순화한 모델을 이용하여 덤프각도에 따른 슬라이딩 데크의 진출길이 계산식을 도출하였다. 도출한 계산식을 수치해석 프로그램을 이용하여 덤프각도에 따른 슬라이딩 데크 진출길이 계산을 수행하였고, 시스템의 최대 최소 각도에서의 진출길이를 파악 하였다. 신뢰성 확보를 위해 시스템의 축소모형을 제작하여 실험을 통해 계산식을 검증하였다. 슬라이딩 데크 재질과 두께를 결정하기 위해 데크를 단순화 하였고, 데크 제작에 쓰이는 대표적인 재질 두 가지를 선정하였다. 단순화한 모델을 해석 프로그램을 사용하여 최대 하중을 받는 조건에서 두께와 재질에 따른 변형량과 응력을 비교하였다. 해석결과 ATOS80을 이용할 경우 두께를 줄이면서 더 적은 변형량을 가지게 되어 경량화를 이룰 수 있다.

• 한국항만경제학회지
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• 제32권4호
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• pp.127-147
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• 2016

본 연구는 1997년 부두운영회사(TOC)제 도입 이후 적용과정에서 다수의 문제점이 노정되어 온 현행(2003~2014) TOC제 부두의 임대료 체계를 합리적으로 개선하기 위한 방안을 제시하는데 그 목적이 있다. 이에 따라 표준화, 단순화, 형평성 도모라는 세 가지 방향으로 임대료 체계를 개편하고자 하였다. 최종 개편대안은 재산가치와 정책요율인 무역항사용료가 반영된 임대료 산정 방식을 채택하였다. 왜냐하면 현행 임대료 체계의 가장 큰 문제점을 해소하면서 개편에 따른 혼란을 최소화할 수 있기 때문이다. 나아가 적정대안에 의해 재산정된 안벽임대료의 급격한 인상을 방지하기 위해 TOC제 부두별 개편안벽임대료가 기존 선석임대료와 동일하게 되는 개별 조정률을 도입하였다. 이는 임대인인 정부와 항만공사가 부두운영회사(TOC)의 임대료 부담을 경감하는 정책적 목적이 우선될 필요성이 높았기 때문이다. 본 연구는 임대재산의 재산가치를 반영함은 물론 단순하면서도 표준화된 새로운 TOC제 부두 임대료 체계를 마련했다는 데 큰 의의가 있다. 또한 정책요율(무역항 시설사용료)이 적용되는 야적장 통로 창고(상옥) 임대료를 동일한 기준으로 모든 부두에 적용시킴으로써 일정 부문 형평성을 확보한 것도 큰 성과로 평가할 수 있다. 다만 개별 조정률을 도입함에 따라 안벽임대료가 면적에 비례하여 부과되지 못해 형평성이 저해되는 한계점도 동시에 내포하고 있다. 향후 부두 운영 여건이 개선되는 정도에 따라 단계적으로 부두별 개별 조정률을 동일한 목표 조정률인 0.5 수준으로 현실화시켜야 할 것이다.

• 인지과학
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• 제16권4호
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• pp.323-331
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• 2005

본 논문은 조명 변화에 강인하며 중립 표정과 같은 표정 측정의 기준이 되는 단서 없이 다양한 내적상태 안에서 얼굴표정을 인식할 수 있는 개선된 시스템을 제안한다. 표정정보를 추출하기 위한 전처리 작업으로, 백색화(whitening) 단계가 적용되었다. 백색화 단계는 영상데이터들의 평균값이 0이며 단위분산 값으로 균일한 분포를 갖도록 하여 조명 변화에 대한 민감도를 줄인다. 백색화 단계 수행 후 제 1 주성분이 제외된 나머지 주성분들로 이루어진 PCA표상을 표정정보로 사용함으로써 중립 표정에 대한 단서 없이 얼굴표정의 특징추출을 가능하게 한다. 본 실험 결과는 또한 83개의 내적상태와 일치되는 다양한 얼굴표정들에서 임의로 선택된 표정영상들을 내적상태의 차원모델에 기반한 얼굴표정 인식을 수행함으로써 다양하고 자연스런 얼굴 표정 인식을 가능하게 하였다.

• KIEAE Journal
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• 제10권3호
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• pp.89-96
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• 2010

In comparison with ordinary or heavy-weight concrete, light-weight air void concrete has the good aspects in optimizing super tall structure systems for the process of design considering wind load and seismic load by lightening total dead load of buildings and reducing natural resources used. Light-weight air void concrete has excellent properties of heat and sound insulating due to its high amount porosity of air voids. So, it has been used as partition walls and the floor of Ondol which is the traditional Korean floor heating system. Under the condition of which the supply of light-weight aggregates are limited, the development of light-weight concrete using air voids is highly required in the aspects of reduced manufacturing prices and mass production. In this study, we investigated the physical properties and thermal behaviors of specimens that applied different mixing ratios of foaming agent to evaluate the possibility of use in the structural elements. We proposed the estimating equation for compressive strength of each mix having different ratio of foaming agent. We also confirmed that the density of cement matrix is decreased as the mixing amount of foaming agent increase up to 0.6% of foaming agent mixing ratio which was observed by SEM. Based on porosity and compressive strength of control mortar without foaming agent, we built the estimating equations of compressive strength for mortars with foaming agent. The upper limit of use in foaming agent is about 0.6% of the binder amount. Each air void is independent, and size of voids range from 50 to $100{\mu}m$.