• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.252-257
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• 1998

국내 원전에 신뢰도 기반 정비(RCM : Reliability Centered Maintenance) 기법을 도입하기 위해 수행하고 있는 영광 1,2호기 시법계통 RCM 분석에서 관련 기기의 고장데이터를 RCM 분석 방법론에 따라 분석하였다. 본 논문에서는 작업의뢰서와 작업보고서 기록내용을 토대로 지배적인 고장모드 및 다빈도 고장발생 기기를 파악하여 고장원인을 분석하였으며, 기기 유형으로 분류하여 고장들을 분석하였다. 분석결과 지배적인 고장모드는 EPRI에서 분류한 고장모드에 모두 포함되었으며, 고장빈도가 높은 기기의 고장원인은 운전환경, 사용유체, 운전형태, 기기 형식 등에 따라 고장메커니즘이 다르게 나타나는 것으로 분석되었다. 기기 유형으로 분류하여 고장모드별로 고장율을 분석한 결과 미국의 Generic Data(IEEE Std 500-1984)와 근소한 차이를 보이거나 약간 낮은 것으로 분석되었으며, 고장율이 높은 기기 유형을 단위 기기별로 세분화하여 분석한 결과 공기구동 조절벨브의 외부누설 고장율은 1.10E-06 이지만 충전유량 조절밸브의 고장율은 1.70E-05로서 약 10배 정도로 고장율이 높은 것으로 분석되었다. 기기별로 세분화한 고장을 분석 결과는 시범계통 RCM 분석시 고장모드 영향분석(FMEA. Failure Mode and Effective Analysis) 단계에서 필수기기를 선정하는 하나의 인자로 활용하였으며, 고장율의 역수로 구한 고장간 평균시간(MTBF:Mean Time Between Failure)은 정비주기 선정시 기초데이터로 활용된다.

• Annual Conference of KIPS
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• 2013.11a
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• pp.1096-1097
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• 2013

최근 Twitter를 비롯한 소셜 네트워크 서비스의 급속한 확산으로 인해, 많은 수의 SNS 메시지가 실시간으로 생성되고 있다. 이러한 SNS 상의 모든 글을 읽어보는 것은 현실적으로 불가능하며, 여러 포탈 사이트에서 제공되는 실시간 검색어 순위만으로는 상세 내용을 직관적으로 파악하기 어렵다. 따라서, 이러한 SNS상의 글을 실시간으로 분석하여 최신의 트렌드를 찾고 이와 연관된 내용을 분류 및 요약할 수 있다면, 사용자에게 유용한 최신 정보를 생성하여 제공할 수 있다. 본 논문에서는 Tweet 들을 분석하여 얻은 트렌드 키워드를 기반으로 관련된 Tweet 들을 주제 별로 분류한 후, 각 주제 별로 세부 내용을 요약해서 제공하는 기법을 제안한다. 제안하는 기법은 실시간으로 생성되는 Tweet 내에서 최근 화제가 된 트렌드 및 연관 키워드를 추출해낸다. 그 후, 해당 키워드가 출현한 Tweet 내에서 핵심 키워드를 찾고, 이를 기반으로 Tweet 들을 각각의 주제별로 분류하고 각 주제를 '이슈'로 정의한다. 마지막으로, 특정한 이슈에 해당되는 Tweet들을 분석하여 각 이슈 별로 키워드 리스트 및 단문 형식으로 요약된 줄거리를 생성한다. 제안된 기법을 바탕으로 프로토타입 시스템을 구현하고, 다양한 실험을 통하여 이슈 검출 기법의 유용성 면에서 성능을 평가한다.

• Journal of KIISE:Software and Applications
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• v.33 no.10
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• pp.836-850
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• 2006

Nowadays, due to the rapidly increasing number of package software products, quality test has been emphasized for package software products. When testing software products, one of the most important factors is to select metrics which form the bases for tests. In this paper, the types of package software are represented as characteristic vectors having probabilistic relationships with metrics. The characteristic vectors could be regarded as indicators of software type. To assign the metrics for each software type, the past test metrics are collected and analyzed. Using Bayesian belief network, the dependency relationship network of the characteristic vectors and metrics is constructed. The dependency relationship network is then used to find the proper metrics for the test of new package software products.

• Journal of Korean Society of Steel Construction
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• v.11 no.2 s.39
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• pp.109-116
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• 1999

This paper presents an experimental study on the behavior of CFT Column to H-Beam Endplate Connections with penetrated H/T bolts under monotonic loading. The object of this study is to estimate accurately the effect about the thickness of endplate and the arrangement of H/T bolts which was not got a grip on the results reported in the previous paper. Main parameters are the thickness of endplates (12mm, 16mm) and the arrangemement of H/T bolts (EP1, EP2, EP3 Type). The experimental results compared and analysed. 1) The specimens were classified by Bjorhovde's and EC3's method. 2) A formula to predict the ultimate moment of connection was derived based on the T-stub model, and theoretical value $(_tM_u)$ computed by the formula corresponded to the experimental value $(_eM_u)$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.101-111
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• 2013

In this study, DEA (Data Envelopment Analysis) was carried out on the four bridges, which have the same extension (L=1,615m), in order to select the most superior, economical method of construction using the LCC concept of each bridge structure in the case of the Ulsan-Pohang double track railway which is scheduled to be constructed. DEA models were analyzed with the CCR model, which was designed for the evaluation of relative efficiency of each model. The initial construction costs, maintenance costs, indirect costs (user costs + indirect loss of social costs), and life cycle costs were used as input variables, and average duration was applied as the output variable. LCC was applied to calculate the input variables, and to get the costs of LCC, 100 years of period and 4.83% of real discount rate were applied, and the costs are classified into initial construction, maintenance, user, and indirect loss of social cost. The analysis results showed that the Method 2 and 3 were evaluated as the most efficient, and the other alternatives were evaluated as the following order; Method 1, the default, and Method 4.

• Journal of Korean Library and Information Science Society
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• v.52 no.2
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• pp.85-106
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• 2021

The purpose of this study is to analyze the form and color of the letter layout among 31 expression methods of official posters during the library week from 1964, for 57 years, and to propose the direction of poster production in the future by revealing what citizens prefer most by conducting a survey based on the results. As a result of analyzing the poster expression form for achieving the purpose of the study, the most common character layout was 'the top position of the character' in 13 out of 31 (41.9%), and in color, 'chromatic color' in 30 out of 31 (96.8%), and the temperature of color with 'cold color', 'fading color' and 'shrink color' in 18 out of 31 (58.1%), respectively. The results of the survey showed that the most preferred was 'top position of characters' for letter layout, and 'chromatic color' and 'cold color', 'advance color' and 'expansion color' were the most preferred for the color classification. Therefore, the character layout of the weekly poster for the library needs to be produced using 'the center position of the letter', and the colors need to be made using 'chromatic color', 'warm color', 'advance color' and 'expansion color'.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.640-655
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• 2013

The purpose of this study is to analyze the cognitive demands level of the description about 'changes of state' and 'kinetic theory' on the 'science 1' textbooks by the 2007 revised curriculum. The three types of curriculum analysis taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science 1' textbooks. The most higher level of cognitive demands about the concepts have been discussed here due to the focus of the concepts. The first, the cognitive demand level about 'three states of substances' depending on the motion of their particles in 6 textbooks is a early formal operational stage because of using by the application of kinetic theory. The second, the cognitive demand level about 'diffusion' and 'evaporation' is a early formal operational stage, because the particles move around faster so they can change their position. The third, the cognitive level of the pressure and volume in a gas is a early formal operational stage because of explaining only phenomena in simple correspondence with formal model of kinetic theory. And simple functional relationships beyond linear on the graph of the volume and pressure of gas, the volume and temperature of gas is also a early formal operational stage. The fourth, the cognitive level of the energy of heat by a change of the state is also a early formal operational stage because kinetic theory picture accepted as providing explanation by the change of the state. And functional relationships beyond linear on the graph of the explanation of boiling point of water in water is also a early formal operational stage.

• Journal of forensic and investigative science
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• v.2 no.1
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• pp.23-31
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• 2007

Apartments are built in small countries to accommodate densely populated cities and maximize urbanization. Many apartment complexes have been built in recent reconstruction or redevelopment projects. An increase in crime has resulted due to residents living in a narrow space. Larceny is the most commonly reported crime in apartment complexes. Apartments can be classified as stairway, hallway, or plane surface. This study compares and analyzes the frequency of theft by apartment type to assist in creating a safer residential space. In America and England, scholars studied to make a safer residential space, and have applied the theory of 'the Defensible Space' and 'Crime Prevention Through Environmental Design(CPTED)' since 1970s. Korean apartment design now reflects CPTED in new apartment construction. In this study, 12 apartment complexes were selected in Changwon city to conduct analysis of theft in selected complexes. The study will cover housing invasion theft, motorcycle and car theft and snatching. The most frequency larceny is motorcycle and car theft, the second is housing invasion theft, and the least frequent is snatching. More residents' motorcycles and cars are damaged in a hallway style apartment. More frequently inhabitants have their possessions snatched on a stairway form. 1) When we build new apartment complexes, we must plan to improve territoriality and enhance a natural surveillance by reinforcing dwellers' relationship. Through planning we can prevention the larceny in apartments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1450-1460
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• 2015

This study is to analyze various methods of block design elements applied in the recent apartment housing design competitions for Sejong city. It is expected to find the new design trend and good design characteristics of apartment building forms to use as the basic data of apartment housing design, because it is a case study on the ambitious design competition of the city that many major architectural firms in Korea entered and eager to propose new ideas. The results of this study are following : (1) The forms of slab block are classified into 8 types(the best applying one is ㄱ type). The forms of point block are classified into 9 types(the best applying ones are ㅁ, L and - type). (2) For the shapes of core, the forms of opposite core are classified into 6 types, the forms of parallel core are 3 types. (3) The forms of roof are classified into 4 types. The flat type is applied to 95 percent of the total cases. (4) The shapes of block mass are classified into 5 types(the best applying ones are general and void type), facade forms are 3 types(the best applying one is horizontal division type).

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.21-31
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• 2015

The Internet users want to get real-time services for various multi-media applications. Network traffic rate has been rapidly increased, and data amounts that the Internet has to carry have been exponentially increased. A packet is the basic unit in transferring data at the Internet, and packet classification is one of the most challenging functionalities that routers should perform at wire-speed. Among various known packet classification algorithms, area-based quad-trie (AQT) algorithm is one of the efficient algorithms which can lookup five header fields simultaneously. As a representative space decomposition algorithm, the AQT requires a small amount of memory in storing classification rules, but it does not provide high-speed classification performance. In this paper, we propose a new packet classification algorithm by applying a binary search for the codewords of the AQT to overcome the issue of the AQT. Throughout simulation, it is shown that the proposed algorithm provides a better performance than the AQT in the number of rule comparisons with each input packet.