• 한국정보통신학회논문지
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• 제12권6호
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• pp.1026-1031
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• 2008

현재 가정과 소규모 사업장에서 재정적인 변화와 개인 커뮤니케이션 그리고 원격의료에 이르기까지 점점 GPON 사용이 일반화 되어가고 있다. 이러한 PON의 다중사용 때문에 개인정보 보호와 커뮤니케이션 보호를 위한 보안의 필요성이 더더욱 커지고 있다. 이를 위해 이 논문에서는 Virtex4 FPGA를 기반으로 AES의 카운터 모드를 구현하였다. 본 논문에서 구현된 구조는 pipeline 구조 구현을 위하여 크게 세 가지 특징을 가지고 있는데 1) composite filed 연산을 이용한 Subbyte, 2) efficient MixColumn transformation, 그리고 3) on-the-fly key scheduling이다. 구현된 S-box는 면적의 17% 감소와 on-the-fly key 스케줄링 기법으로 pipeline 구조에 특화된 key-expander 기능을 구현하였다.

• 한국도로학회논문집
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• 제13권4호
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• pp.211-220
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• 2011

최근 대중교통지향형개발(TOD)이 활발해지며, 역세권의 환경 변화를 통하여 국내의 대중교통 이용 증진을 시키기 위해서는 TOD 통합계획요소를 종합적으로 고려한 역세권 유형과 이용수요에 관한 실증분석이 전제되어야 향후 계획수립시 활용이 가능 할 것이다. 본 연구는 서울시 역세권을 대상으로 다양한 TOD 영향요인을 파악하고, 대중교통 이용수요와 연관성을 규명하기 위한 실증분석을 진행하였다. TOD의 대표적 요소인 Density, Diversity, Accessibility에 대한 자료를 수집하고, 요인분석과 회귀모형을 구축하였다. 분석결과 (1) 요인분석을 토대로 7개 영향요인이 도출되었으며, Factor 1(Diversity/토지이용복합도 (LUM)), Factor 2(Density/개발밀도수준), Factor 3(Accessibility/대중교통시설공급수준), Factor 4(Design/가로설계수준), Factor 5(Green/연계교통시설(보행자, 자전거), Factor 6(Design/지하철시설규모), Factor 7(Accessibility/대중교통운영수준)로 유형화되었다. (2) 요인-회귀분석 결과를 토대로 역세권 승하차 인원에 긍정적(+) 영향을 미치는 주요 요인은 Factor 1(Diversity : 토지이용복합도(LUM) 요인), Factor 3(Accessibility : 대중교통시설공급수준), Factor 2(Density : 개발밀도수준), Factor 5(Design/연계교통시설(보행자, 자전거), Factor 6(지하철시설규모)로 나타났다. 다음으로 역세권의 승하차 인원에 부정적(-) 영향은 Factor 7(Accessibility/대중교통운영수준)로 나타났으며, 가장 높은 영향력을 가지는 것으로 나타났다. 이는 지하철과 버스의 배차간격이 증가할 경우 이용수요가 감소하기 때문이다.

• 대한치과교정학회지
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• 제41권1호
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• pp.51-58
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• 2011

Objective: To evaluate the shear bond strength (SBS), fracture mode, wire pull out (WPO) resistance and microleakage between low-shrinking and conventional composites used as a lingual retainer adhesive. Methods: A total of 120 human mandibular incisor teeth, extracted for periodontal reasons, were collected. Sixty of them were separated into two groups. To determine the SBS, either Transbond-LR (3M-Unitek) or Silorane (3M-Espe) was applied to the lingual surface of the teeth by packing the material into standard cylindrical plastic matrices (Ultradent) to simulate the lingual retainer bonding area. To test WPO resistance, 20 samples were prepared for each composite where the wire was embedded in the composite materialand cured. Then tensile stress was applied until failure of the composite occurred. The remaining 60 teeth were divided into two groups and multi-stranded 0.0215-inch diameter wire was bonded with the same composites. Microleakage was evaluated by the dye penetration method. Statistical analyses were performed by Wilcoxon, Pearson chi-square, and Mann-Whitney-U tests at p < 0.05 level. Results: The SBS and WPO results were not statistically significant between the two groups. Significant differences were found between the groups in terms of fracture mode (p < 0.001). Greater percentages of the fractures showed mix type failure (85%) for Silorane and adhesive (60%) for Transbond-LR. Microleakage values were lower in low-shrinking composite than the control and this difference was found to be statistically significant (p < 0.001). Conclusions: Low-shrinking composite produced sufficient SBS, WPO and microleakage values on the etched enamel surfaces, when used as a lingual retainer composite.

• 복식문화연구
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• 제6권4호
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• pp.213-228
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• 1998

The purpose of this study is to defined the conception and characteristics of Post-Modernism and dealt with how they are expressed in costume. Major characteristics of Post-Modernism are Historicism, Pluralism, and Eclecticism and these are reflected in the costume. 1. Historicism of Post-Modernism is a trend recreate artistic symbolism which Modernism lacked in reference to historical factors of the past. It has been as a trend of restoration and an ornamental trend can be included in the category of historicism in that it restored historical ornaments. 2. Pluralism of Post-Modernism means an open-hearted attitude toward everything. In costume, it has been expressed as a trend of mixed fashion style such as ecology, street fashion and futurism, collapse and mix of genres, diversity of materials and emphasis on texture caused by assemblage, change of the use to escape from the conventional system and avant-garde. 3. Eclecticism of Post-Modernism is expressed as a blended fashion style based on the principal of de-dualism. It has several trends ; exotic trend by mixing both oriental and western culters, androgyny which is a mixed image of an and woman, and a trend to use many kinds of materials together influenced by collage which is an eclectic mode.

• 전기학회논문지
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• 제63권7호
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• pp.867-874
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• 2014

The pumped storage power plants have excellent load following characteristics. It can also be committed quickly for synchronous reserve when it is in the generating mode because it can readily increase its generating power and, consequently, increases the overall system reliability. There are strong incentives for standing the system reliability. Additionally, $CO_2$ emission can be typically impacted due to operation of pumped generators. The increase or decrease of $CO_2$ depends on the generation mix. This paper proposes evaluation of reliability, economy and environment of power system considering pumped generator. This paper describes three case studies of the reliability and economy and environment according to capacity factor and storage capacity of pumped generators. The probabilistic production simulation model is used in this paper. The practicality and effectiveness of the proposed approach are demonstrated by simulation studies for a real size power system model on the $5^{th}$ power plan in Korea.

• 조명전기설비학회논문지
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• 제19권7호
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• pp.100-106
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• 2005

일반적으로 자외선(UV)을 발생하기 위한 방전등 구동용 직류 전원장치는 하드 스위칭 모드로 동작되어지는 고주파 스위칭 DC-DC 컨버터가 사용되고 있다. 구체적으로 전원장치는 전자 노이즈 장해에 의한 전자 회로의 오동작이나 각 구성 소자의 발열의 문제 등이 시스템의 신뢰성을 저하시키는 원인이 되고 있다. 그러므로 본 논문에서는 소프트 스위칭 회로 기술을 사용한 고주파 링크 DC-DC 컨버터로서 먼저 구체적으로 1차측 위상 천이 PWM DC-DC 컨버터와 제안한 2차측 위상 천이 PWM DC-DC 컨버터를 조합하여 방전등 구동용 직류 전원장치를 제안하였다. 제안하는 방전등 구동용 직류 전원장치는 시뮬레이션과 실험을 통하여 그 타당성을 서술하였다.

• 한국압력기기공학회 논문집
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• 제16권1호
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• pp.30-36
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• 2020

In SMART, the flow mixing header assembly (FMHA) is used to mix the coolant flowing into the reactor core to maintain a uniform temperature. The FMHA is designed to have enough stiffness so the resonance with reactor internal structures does not occurs during the pipe break and the seismic accidents. Since the gap between the FMHA and the core support barrel assembly is very narrow compared with the diameter of FMHA, the hydrodynamic mass effect acting on the FMHA is not negligible. Therefore the hydrodynamic mass characteristics on the FMHA are investigated to consider the fluid and structure interaction effects. The result of modal analysis for the dry and underwater conditions, the natural frequency of primary vibration mode for the horizontal direction is reduced from 136.67 Hz to 43.76 Hz. Also the result of frequency response spectrum seismic analysis for the dry and underwater conditions, the maximum equivalent stress are increased from 13.89 MPa to 40.23 MPa. Therefore, reactor internal structures located in underwater condition shall consider carefully the hydrodynamic mass effects even though they have sufficient stiffness required for performing its functions under the dry condition.

• 복식
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• 제50권2호
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• pp.15-28
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• 2000

This paper focuses on the sports look expressed in 20th century fashion. It is Age of Sport just as rock'n roll became dominant cultural form of the 1960's and 1970's . In the 1990's the sportsware is fashion. Designers gazing into the future are inspired by the details and functionality of clothing for snow boarding , skiing , motorbike racing and fitness. No doubt fashion in 2000 will also be full of references to it. Since the late 1960's the sportswear that was originally a term for clothing worn for various sports activities in the 1890's has changed and is now considered as fashion for day as well as evening. This has occurred primarily in the U.S. due to the adoption of less formal lifestyles by Americans. while the sportwear is the term which stemmed from the need for functionality in sports, sports look is the style inspired by the formative elements, that is, the details, the shilhouette, and the colors of the sportswear. New technologies for sports, the powerful influence of youthful culture, and the celebritizations of the sports stars made the sports look much hipper and more popular. It can be categoried into three aesthetic values, I. e., the functional sports look,, purism and no useless ornament, the street sports look with fun, androgynous and unisex mode and the mix and match of different texture and colors, and the futuristic sports look with new high tech fabrics and avant-garde style.

• Computers and Concrete
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• 제7권5호
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• pp.421-435
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• 2010

This paper utilizes the modified Davis model and the mode coupling theory, as parts of the electrolyte solution theory, to investigate the diffusivity of the ion in concrete. Firstly, a computational model of the ion diffusion coefficient, which is associated with ion species, pore solution concentration, concrete mix parameters including water-cement ratio and cement volume fraction, and microstructure parameters such as the porosity and tortuosity, is proposed in the saturated concrete. Secondly, the experiments, on which the chloride diffusion coefficient is measured by the rapid chloride penetration test, have been carried out to investigate the validity of the proposed model. The results indicate that the chloride diffusion coefficient obtained by the proposed model is in agreement with the experimental result. Finally, numerical simulation has been completed to investigate the effects of the porosity, tortuosity, water-cement ratio, cement volume fraction and ion concentration in the pore solution on the ion diffusion coefficients. The results show that the ion diffusion coefficient in concrete increases with the porosity, water-cement ratio and cement volume fraction, while we see a decrease with the increasing of tortuosity. Meanwhile, the ion concentration produces more obvious effects on the diffusivity itself, but has almost no effects on the other ions.

• 한국건축시공학회지
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• 제4권3호
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• pp.133-141
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• 2004

The object of this study is to investigate experimentally the shear behavior of reinforced concrete beams using recycled coarse aggregate. At first, the specimens are manufactured for the compressive strength of 210kgf/$\textrm{cm}^2$ with recycled coarse aggregate ratio of 0%, 20%, 40%, 60%, 80%, 100%, respectively. From the results, Reinforced concrete beams using recycled coarse aggregate were made with recycled coarse aggregate ratio of 0%, 20%, 40%, 60%, 80%, with stirrups and recycled coarse aggregate ratio of 0%, 20%, 40% without stirrups. The results of crack pattern and failure mode, load-displacement curve(center point and load point) and load-steel curve(compressive, tensile, stirrup) were analysed. It is concluded from the test that the shear behavior of recycled concrete beams is determined to have similar behavior of normal concrete beams. Therefore, from this study the application of recycled concrete to concrete structures may be possible. But, for using the recycled concrete widely, it is expected that the more studies on quality control, substitution ratio and mix design related with recycled concrete are necessary.