• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1033-1038
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• 2005

As a global effort to conservate the environment, life cycle assessment(LCA) which considers the environmental impact through the life cycle of a product, from acquiring of resources to scrapping, has been actively applied. The LCA is a tool to calculate quantitatively the environmental impacts caused by products or services through their life cycles. The list of numerous data should be analyzed, stored and conducted in order to assess the environmental impacts. Therefore, it is necessary to develop a software for LCA, which can perform the interpretation as well as the environment impact assessment to execute the analysis of such a large number of data effectively. At this time, for the existing some kinds of general LCA softwares, the information about all of input and output should be fed directly and the conclusion is deduced by linking to the database from the public authorized organizations. That makes it possible to evaluate the environmental grades accurately, but it is too slow and difficult for general users to operate and applied it into an electric motor unit(EMU). Therefore, in this research, the basic model was designed, which is based on construction of database structure of the software and organization of architecture, to develop an advanced software for EMU according to user and purpose of it by benchmarking of domestic and international softwares. The result of this study would be applied to develop the LCA software in the future.

• Computers and Concrete
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• 제6권4호
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• pp.281-303
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• 2009

The lack of safety of bridge deck structures causes frequent repair and strengthening of such structures. The repair induces great loss of economy, not only due to direct cost by repair, but also due to stopping the public use of such structures during repair. The major reason for this frequent repair is mainly due to the lack of realistic and accurate assessment system for the bridge decks. The purpose of the present research was to develop a realistic expert system, called Bridge Slab-Expert which can evaluate reasonably the condition as well as the service life of concrete bridge decks, based on the deterioration models that are derived from both the structural and environmental effects. The diagnosis assessment of deck slabs due to structural and environmental effects are developed based on the cracking in concrete, surface distress and structural distress. Fuzzy logic is utilized to handle uncertainties and imprecision involved. Finally, Bridge Slab-Expert is developed for prediction of safety and remaining service life based on the chloride ions penetration and fick's second law. Proposed expert system is based on user-friendly GUI environment. The developed expert system will allow the correct diagnosis of concrete decks, realistic prediction of service life, the determination of confidence level, the description of condition and the proposed action for repair.

• International Journal of Internet, Broadcasting and Communication
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• 제14권4호
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• pp.121-131
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• 2022

We look at the initial stage of Meta (previous Facebook)'s new metaverse platform and investigate its platform design in pre-launch and ignition life stage. From the Rocket Model (RM)'s theoretical logic, the results reveal that Meta firstly focuses on investing in key content developers by acquiring virtual reality (VR), video, music content firms and offering production support platform of the augmented reality (AR) content, 'Spark AR' last three years (2019~2021) for attracting high-potential developers and users. In terms of three matching criteria, Meta develops an Artificial Intelligence (AI) powered translation software, partners with Microsoft (MS) for cloud computing and AI, and develops an AI platform for realistic avatar, MyoSuite. In 'connect' function, Meta curates the game concept submitted by game developers, welcomes other game and SNS based metaverse apps, and expands Horizon Worlds (HW) on VR devices to PCs and mobile devices. In 'transact' function, Meta offers 'HW Creator Funding' program for metaverse, launches the first commercialized Meta Avatar Store on Meta's conventional SNS and Messaging apps by inviting all fashion creators to design and sell clothing in this store. Mata also launches an initial test of non-fungible token (NFT) display on Instagram and expands it to Facebook in the US. Lastly, regarding optimization, especially in the face of recent data privacy issues that have adversely affected corporate key performance indicators (KPIs), Meta assures not to collect any new data and to make its privacy policy easier to understand and update its terms of service more user friendly.

• 한국도로학회논문집
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• 제18권3호
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• pp.47-57
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• 2016

PURPOSES : This study aims to examine the differences between the existing traffic demand forecasting method and the traffic demand forecasting method considering future regional development plans and new road construction and expansion plans using a four-step traffic demand forecast for a more objective and sophisticated national highway maintenance. This study ultimately aims to present future pavement deterioration and budget forecasting planning based on the examination. METHODS : This study used the latest data offered by the Korea Transport Data Base (KTDB) as the basic data for demand forecast. The analysis scope was set using the Daejeon Metropolitan City's O/D and network data. This study used a traffic demand program called TransCad, and performed a traffic assignment by vehicle type through the application of a user equilibrium-based multi-class assignment technique. This study forecasted future traffic demand by verifying whether or not a realistic traffic pattern was expressed similarly by undertaking a calibration process. This study performed a life cycle cost analysis based on traffic using the forecasted future demand or existing past pattern, or by assuming the constant traffic demand. The maintenance criteria were decided according to equivalent single axle loads (ESAL). The maintenance period in the concerned section was calculated in this study. This study also computed the maintenance costs using a construction method by applying the maintenance criteria considering the ESAL. The road user costs were calculated by using the user cost calculation logic applied to the Korean Pavement Management System, which is the existing study outcome. RESULTS : This study ascertained that the increase and decrease of traffic occurred in the concerned section according to the future development plans. Furthermore, there were differences from demand forecasting that did not consider the development plans. Realistic and accurate demand forecasting supported an optimized decision making that efficiently assigns maintenance costs, and can be used as very important basic information for maintenance decision making. CONCLUSIONS : Therefore, decision making for a more efficient and sophisticated road management than the method assuming future traffic can be expected to be the same as the existing pattern or steady traffic demand. The reflection of a reliable forecasting of the future traffic demand to life cycle cost analysis (LCCA) can be a very vital factor because many studies are generally performed without considering the future traffic demand or with an analysis through setting a scenario upon LCCA within a pavement management system.

• 해양환경안전학회지
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• 제20권5호
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• pp.558-563
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• 2014

본 연구에서는 해상에서의 저체온증 사망위험을 감소시키기 위해, 배의 길이 20미터 미만의 우리나라 소형어선에 비치하기 적합한 구명뗏목의 성능기준을 제안했다. 우리나라에는 소형어선용 구명뗏목이 사용되고 있지 않으며 관련 성능기준도 없다. 국내외 및 국제표준의 성능기준을 비교하고, 외국산 구명뗏목 및 본 연구로 개발된 가방형 시제품(2 4인승)의 성능 평가결과를 분석했다. 그 결과, 근해어선의 구명뗏목에는 ISO 9650-1 기준을 적용하고, 연안어선의 구명뗏목에는 ISO 9650-2보다 기준을 낮추어 적용하는 것이 적절할 것으로 판단된다.

• 가정과삶의질연구
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• 제25권5호
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• pp.31-46
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• 2007

The purpose of this study was to determine the differences in internet use motivations and problem behaviors among vocational high school students according to internet addiction and family system type. Five hundred vocational high school students from Daegu took part in the survey. The questionnaire survey consisted of an internet addiction self-assessment scale, a family system type scale, an internet use motivation scale, and a problem behavior scale. The data was analysed using MANOVA and Cronbach a, and the $Scheff\acute{e}$ test was used for post-hoc analysis. The major findings of this study were as follows: First, the study found significant differences in adolescent internet use motivation according to internet addiction. Adolescents in the high dangerous user group showed higher communicative, experiential, and addictive motivations than adolescents in potentially dangerous and normal user groups. Also, there were no significant differences in informative motivation according to internet addiction. Regardless of internet addiction, adolescents tend to use the internet to search for information and to solve problems. Second, there were significant differences in adolescents' problem behaviors according to internet addiction. More specifically, adolescents who were in the high dangerous user group displayed more problem behaviors toward their body, family, school, and society than adolescents in the potentially dangerous and the normal user groups. Third, an adolescent's family system type significantly influenced his/her internet use motivation. Adolescents from an extreme family showed higher communicative and addictive motivations than adolescents from middle and balanced families. Fourth, there were significant differences in the problem behaviors of adolescents according to family system types. Adolescents from an extreme family showed more problem behaviors toward their body, family, school, and society than adolescents from middle and balanced families.

• 한국콘텐츠학회논문지
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• 제14권4호
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• pp.19-28
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• 2014

최근 IT산업의 발전은 우리의 삶을 보다 윤택하게 만들어주고 있다. 특히, 스마트폰의 GPS를 이용하여 개인의 위치를 검출하는 다양한 연구가 진행되고 있으며, 긴급구조기관 등에서 적극 활용하려 하고 있다. 하지만 기존 이러한 방식은 임의의 반경 영역을 생성하여 사용자가 해당 영역이 설정된 공간에 진입하거나 이탈하였을 경우 미리 지정된 사용자의 보호자나 관제기관으로 사용자의 위치정보를 전송하는 방법이 시행되고 있지만 특정 길, 놀이동산과 산행 등 정형화되지 않은 공간 및 경로에 대해서는 기존의 반경 영역을 생성하는 방식을 사용할 경우 세부적인 영역 설정이 어려웠다. 본 논문에서는 스마트 기기나 웹에서도 세부적인 영역을 쉽게 설정하기 위해 기존 서비스에서 이용하는 반경 방식을 개선하여 반경과 반경 사이를 연결하여 영역을 설정하는 방법을 제안하였다. 또한 제안하는 위치 기반 영역 설정 방법 및 이탈 검출을 활용하여 사용자의 위치를 검출하는 연산 과정에서 연산 결과를 비교하여 자원 사용을 최적화할 수 있는 방법을 제안한다.

• 전자공학회논문지CI
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• 제42권4호
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• pp.25-32
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• 2005

모바일 디바이스, PDA 센서들의 확산은 실생활 공간이 지능적이고 향상된 서비스를 제공하는 스마트 공간으로 전환되는 유비쿼터스 컴퓨팅 환경이 구축될 수 있도록 하였다. 그러나 보안문제 특히 적절한 인증 및 접근 제어 기술의 부재로 말미암아, 실생활에서의 이러한 컴퓨팅 패러다임의 변화에 있어, 방해 요소가 되고 있으며, 또한 유비쿼터스 컴퓨팅 환경에서는 보안 대책을 마련하고, 사용자의 프라이버시 보장 또한 매우 중요하다 본 논문에서는 유비쿼터스 컴퓨팅 환경을 위한 사용자 프라이버시를 위한 익명성이 보장되는 효율적인 사용자 인증 및 접근 제어 모델을 제안한다. 본 논문의 제안 모델은 공개키 암호 기술이 아닌 MAC 기반의 익명 인증서와 보안 연계 토큰을 이용하여, 사용자 인증 및 접근 제어를 수행함으로써, 컴퓨팅 연산 능력이 컴퓨팅 연산 능력이 비교적 떨어지는 디바이스들에 적합한 모델이다. 또한 암호 연산 처리 측면에서, Kerberos 시스템과 비교하였을 때, 전반적으로 우수함을 알 수 있었다.

• 디지털융복합연구
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• 제10권3호
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• pp.191-196
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• 2012

현재 모바일 또는 유비쿼터스 시스템을 포함한 하이테크 통신 기술의 중요성과 관련된 비즈니스 분야는 성장세를 거듭하고 있다. 개인적 삶의 질을 제고하기 위한 웰빙의 의미에서, ICT 기술은 선택이 아니라 필요 사항이 되고 있다. 본 연구의 첫 번째 목적은 u-휘트니스에 대상으로 TAM의 수용과 관련된 사용자의 인지된 유용성과 사용 용이성에 영향을 미치는 요소들을 인식한다. 이는 다중회귀분석을 통하여 그 사용자 행위에 영향을 미치는 요인을 탐색한다. 이러한 분석 결과와 연계하여 본 연구의 두 번째 목적은 QFD 방법을 사용하여 그 u-헬스 시스템에의 적용 가능성을 제시한다. 즉 본 연구는 QFD 방법을 사용하여 사용자 요구사항과 관련된 특성에 그 TAM의 외부 변수들을 결합할 수 있다는 가능성을 제안하는데 있다. 이러한 연구 결과에 근간하여 그 적합한 시스템이 구축되고 개발될 수 있을 것이다.

• International Journal of Internet, Broadcasting and Communication
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• 제12권1호
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• pp.67-72
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• 2020

The fifth generation (5G) mobile communication has an impact on the human life over the whole world, nowadays, through the artificial intelligence (AI) and the internet of things (IoT). The low latency of the 5G new radio (NR) access is implemented by the state-of-the art technologies, such as non-orthogonal multiple access (NOMA). This paper investigates a practical issue that in NOMA, for the practical channel models, such as fading channel environments, the successive interference cancellation (SIC) should be performed on the stronger channel users with low power allocation. Only if the SIC is performed on the user with the stronger channel gain, NOMA performs better than orthogonal multiple access (OMA). Otherwise, NOMA performs worse than OMA. Such the superiority requirement can be easily implemented for the channel being static or slow varying, compared to the block interval time. However, most mobile channels experience fading. And symbol by symbol channel estimations and in turn each symbol time, selections of the SIC-performing user look infeasible in the practical environments. Then practically the block of symbols uses the single channel estimation, which is obtained by the training sequence at the head of the block. In this case, not all the symbol times the SIC is performed on the stronger channel user. Sometimes, we do perform the SIC on the weaker channel user; such cases, NOMA performs worse than OMA. Thus, we can say that by what percent NOMA is better than OMA. This paper calculates analytically the percentage by which NOMA performs better than OMA in the practical mobile communication systems. We show analytically that the percentage for NOMA being better than OMA is only the function of the ratio of the stronger channel gain variance to weaker. In result, not always, but almost time, NOMA could perform better than OMA.