• Coupled systems mechanics
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• 제7권1호
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• pp.27-42
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• 2018

Behavior of soil is usually described with continuum type of failure models such as Mohr-Coulomb or Drucker-Prager model. The main advantage of these models is in a relatively simple and efficient way of predicting the main tendencies and overall behavior of soil in failure analysis of interest for engineering practice. However, the main shortcoming of these models is that they are not able to capture post-peak behavior of soil nor the corresponding failure modes under extreme loading. In this paper we will significantly improve on this state-of-the-art. In particular, we propose the use of a discrete beam lattice model to provide a sharp prediction of inelastic response and failure mechanisms in coupled soil-foundation systems. In the discrete beam lattice model used in this paper, soil is meshed with one-dimensional Timoshenko beam finite elements with embedded strong discontinuities in axial and transverse direction capable of representing crack propagation in mode I and mode II. Mode I relates to crack opening, and mode II relates to crack sliding. To take into account material heterogeneities, we determine fracture limits for each Timoshenko beam with Gaussian random distribution. We compare the results obtained using the discrete beam lattice model against those obtained using the modified three-surface elasto-plastic cap model.

• 상하수도학회지
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• 제34권1호
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• pp.23-33
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• 2020

With growing expectations for economic cooperation between the two Koreas, there is much interest in participating in the construction of infrastructure in North Korea. In particular, water and sewage infrastructure is the four major social infrastructures in addition to housing, transportation, electricity and telecommunications. North Korea is known to have severe water pollution and ecosystem destruction in major rivers, water pollution and soil pollution in mining areas are serious, and water and sewage infrastructures in cities other than Pyongyang are known to be weak. Preemptive investment in water supply and drainage in North Korea is the foundation for securing the quality of life of the North Korean and is the foundation of public health and industry. It is a leading investment to reduce the cost of unification and is a new growth engine for the water reloded industry. In this study, we proposed a plan to exchange and cooperate in water environment for building water infrastructure of North Korea by examining the data related to water quality, water resources, water disaster, related legal system and human resources exchange situations in North Korea.

• 공학교육연구
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• 제21권2호
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• pp.51-59
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• 2018

The author investigated the momentum of the maker movement and its educational implications with the following four research questions: 1. What is the maker movement? 2. What is the nature of our societal interest in the maker movement? 3. Which learning theories are associated with the maker movement? 4. What are the educational implications of the maker movement? The author reviewed the history of education in terms of the maker movement and concluded that Papert's learning-by-making approach provided a theoretical foundation of the maker movement. The maker movement aims to engage participants in Do-It-Yourself(DIY) activities, the spirit of tinkering, and a hands-on approach. Also, the maker movement meets the educational demands of fostering students' 21st-century abilities and technological literacy. Lastly, the author anticipated the issues that may arise following the introduction of the maker movement in K-12 schools. In conclusion, the author discussed the challenges of the school maker education movement and suggested the bottom-up approach to utilize the school resources of technology and engineering education.

• 한국환경보건학회지
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• 제47권1호
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• pp.55-63
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• 2021

Objectives: Cefotaxime is an antibiotic used to treat several bacterial infections. Specifically, it is used to treat pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, and sepsis. It is given by injection into either a vein or muscle. Antibacterial polymers prepared by chemical bonding and simple blending of antibacterials into polymers has attracted much interest because of their long-lasting antibacterial activity. This study attempted to review the possibility of hydrogel films as functional antibacterial materials by antimicrobial activity. Methods: In this study, CTX-PAA was synthesized by the chemical reaction of polyacrylic acid with cefotaxime by N,N'-Dicyclohexylcarbodiimide (DCC) method. Synthetic antibacterial hydrogel films were then prepared with PVA and CTX-PAA for functional application. Results: The increase in the cefotaxime content of the hydrogel films showed a similar decrease in tensile strength and elongation. The values of films impregnated with chemically bonded cefotaxime showed no significant difference. Antibacterial susceptibility was determined against Streptococcus pneumoniae and Escherichia coli using a standardized disc test. Conclusion: The synthetic antibacterial hydrogel films exhibited broad susceptibility against Streptococcus pneumoniae and Escherichia coli. Notably, the antibacterial effect of antibacterial hydrogel films against Grampositive (Streptococcus pneumoniae) was superior to that against Gram-negative (Escherichia coli).

• 한국지반공학회논문집
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• 제23권5호
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• pp.63-75
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• 2007

Piled raft 기초는 연약지반상에서 과도한 침하와 raft 및 말뚝의 지지력 산정 문제 등으로 적합한 기초는 아닌 것으로 알려져 왔으나 최근 국내외에서 연약지반내 구조물 시공이 증대되면서 연약지반상 piled raft 기초에 대한 관심이 커지고 있다. 이에 본 연구에서는 연약지반에 시공된 piled raft기초의 거동을 분석하였으며 이를 위해 ABAQUS를 이용한 3차원 유한요소 해석을 실시하였다. 해석 시 하중은 등분포하중과 집중하중을 각각 적용하였으며 동일한 조건의 군말뚝과 piled raft 기초 및 다양한 말뚝 배치를 갖는 piled raft 기초를 대상으로 수행하였다. 본 연구결과, 하중형태, 다양한 말뚝 배치 및 근입 깊이에 대한 각각의 침하 및 하중분담특성을 비교, 분석하였으며 이를 통해 연약지반상의 piled raft 기초의 특성을 파악하였다.

• 한국언론정보학보
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• 제36권
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• pp.109-132
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• 2006

방송과 통신의 융합으로 매체와 서비스의 구분이 모호해지면서 공익성의 개념을 새롭게 정립해야 할 필요성이 증가하고 있다. 이에 따라 본 연구에서는 방송통신 융합시대에 산업의 변화에 따라 모든 매체와 서비스에 적용가능한 공익성 개념의 정립을 시도하였다. 방송과 통신의 융합으로 미디어 산업은 콘텐츠, 플랫폼, 네트워크, 단말이라는 가치사슬로 변화하고 있다. 디지털기술의 발전으로 향후 방송과 통신은 이러한 가치사슬에 따라 산업구조 개편이 불가피해지고 있다. 산업구조의 변화는 이념과 규제정책, 그리고 규제체계의 변화를 수반하고 있다. 그렇지만 융합시대에도 미디어 서비스는 기본적으로 공익성 구현의 의무가 있으며, 이러한 공익성 구현의 궁극적인 목표는 수용자 복지의 증진에 있다. 수용자 복지증진을 위해 콘텐츠 측면에서는 내용의 다양성, 공정성, 객관성, 사회적 가치보존, 플랫폼 측면에서는 개인정보 보호, 소비자 보호, 유해정보 차단, 네트워크 측면에서는 안정적 망 유지, 공정경쟁, 단말기 측면에서는 호환성 유지, 디지털 격차해소 등이 필요하다. 그리고 이러한 공익적 가치를 구현하기 위한 법, 제도적 측면의 규제정책 추진이 요구된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2250-2255
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• 2011

There has been a growing interest toward railroad conjunction with opening of high-speed rail in 2004 and concurrent implementation of nation's green growth policies. Meanwhile, users' expectation on service of public transportation, especially railroad has been growing than since ever due to heightened quality of life, entering aging society, voice of equity for minorities, and greater interest in environments of communities. In order to come up with the expectations, actual improvements for user's convenience/comfort and its assessment strategies in terms of service quality level are necessary. This study defines the index of this aspect of service level as 'Sensitivity Quality'. This is conceived as one of the important factors to define travel cost as do the travel time and fare, but hardly taken into consideration when assessing a transportation system or policy-making for a transportation project. The elements included for the assessment of the sensitivity quality in this study are feeling of a ride, conformability and convenience what users feel and recognize using a train. This paper suggests that establishing sensitivity quality elements would contribute in foundation of assessing service quality and provide improved public transportation services through their scientific and objective development and management.

• 한국멀티미디어학회논문지
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• 제21권8호
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• pp.876-887
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• 2018

In this paper, we propose an robust CAMShift method to track stage objects with a camera. In order to solve the problem of tracking object misdetection in existing CAMShift technique, MBR region is detected to separate the background and the subject, and the subject size of the region of interest is calculated to solve the problem of erroneously detecting a large region having a similar color distribution ratio. Also, by applying the color corelogram and MB-LBP to the part that can not be solved by the color ratio and the size limitation, accurate texture tracking is enabled by reflecting the texture characteristics. Experimental results show that the proposed method has good tracking performance for objects that do not deviate from the size of the subject set in the area of interest and accurately extracts the texture characteristics of different subjects with similar color distribution ratios.

• 경영과정보연구
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• 제25권
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• pp.339-370
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• 2008

As the Internet environment develops, Internet has already been being established as important tool of business marketing and branding. In particular, a brand community where customers interact with other customers who have the same interest in brand provides a variety of benefits to customers as well as companies. The brand community makes it possible for company to build, and retain relationships with customers, and capture new market opportunities. Therefore, this study examines the relationship among service quality of brand community, customer value, customer satisfaction, customer trust, and brand community loyalty in online brand communities. The results of empirical analysis can be summarized by the following: First, service quality of brand community had a significant direct effect on customer value. Second, service quality of brand community had a significant direct effect on customer satisfaction. It had also a positive, significant indirect effect on customer satisfaction through customer value and customer trust. Third, service quality of brand community had a significant indirect effect on brand community loyalty through customer satisfaction, customer value, and customer trust. Therefore, These finding will spawn both academic and practitioner interest in brand community and serve as a foundation for further research in this important area.

• 한국가구학회지
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• 제28권3호
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• pp.185-197
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• 2017

With the advent of industrial society, the phenomenon of nuclear families has brought many changes in the family environment. Of changes, a decrease in the number of new-born babies led to one-child families, which then led to an increase in interest in children. Interest in children gave birth to a consumptive trend called "kids marketing," and phenomena of generous investment and consumption for children appear to continue to the future. In reality, too, the consumer market of children's apparel and learning materials for children has sharply increased over the past few years, and products related to children have become the center of family consumptions. Therefore, at this point when children are the center of consumptive life in the family and the relationship between products and users is becoming an increasingly more important variable, the conductive research focusing on children is necessary. These important factors embraced wide areas of activities in research on children, from children's physical changes, children's preference, such as color and material, to children's consumptive environment, as they can provide a foundation for furniture design suitable for children.