• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.283-288
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• 2009

Estimations of oil slick area after M/T Herbei Sprit accident in December 2007 were analyzed using ENVITSAT ASAR(Advanced Synthetic Aperture Radar) microwave and KOMPSAT-2 of high resolution data. Monthly end short-term variations of chlorophyll a concentration before end after M/T Herbei Sprit oil spill accident were also analyzed using SeaWiFS/MODIS ocean color data. The oil slick areas estimated by KOMPSAT-2 and ASAR satellites were 59,456 $m^2$ and 1,168 $km^2$, respectively. The winds before end after oil spill accident were prevailed the northerly and northwesterly winds, and the strength of wind in this accident was stronger than 10 m/sec. In Taean and Anmeon-do, monthly mean chlorophyll a concentrations(6.3 mg/$m^3$ and 3.7 mg/$m^3$) in January 2008 alter the oil spill were higher than those(2.9 mg/$m^3$ and 2.5 mg/$m^3$) in December 2007. Short-term variations of chlorophyll a in these areas were decreased alter one or two weeks of oil spill.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.295-295
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• 2012

염소와 불소 혼합가스와 펄스 직류 전원 플라즈마를 이용하여 GaAs/$Al_{0.2}Ga_{0.8}As$의 선택적 식각을 연구하였다. 식각 주요 공정 변수는 혼합 플라즈마에서 불소 가스의 유량(0~50%) 이었다. 다른 공정 조건은 공정 압력, 펄스 파워, 펄스 주파수, 리버스 시간이 이 있다. 저진공(~100 mTorr) 플라즈마에 대한 연구로 한정하여 기계적 펌프만을 사용하여 공정을 진행하였다. 오실로스코프(Oscilloscope) 데이터에 의하면 가스의 조성 변화에도 척에 걸리는 입력 전압과 전류가 거의 변화가 없었다. $BCl_3/SF_6$플라즈마에서 $SF_6$가스가 10%의 조성에서 GaAs와 $Al_{0.2}Ga_{0.8}As$의 식각 선택비가 약 50:1로 우수한 결과를 나타내었다. 혼합 플라즈마에서 $SF_6$가스의 증가는 GaAs의 식각율과 선택도를 감소시켰다. 그리고 불소 성분 가스의 조성비가 일정량 이상일 경우에는 GaAs와 $Al_{0.2}Ga_{0.8}As$가 거의 식각되지 않았다. 위의 결과들을 종합적으로 보면 펄스 직류 전원 $BCl_3/SF_6$플라즈마에서 불소의 조성비는 GaAs의 선택적 식각에서 중요한 역할을 함을 알 수 있었다.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.70-70
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• 2011

사장교의 적용지간이 증가하여 초장대화하면서 구조안전성을 확보하기 위한 다양한 노력이 시도되고 있다. 본 연구에서는 현재까지 시도된 적이 없는 주경간 1,200m 사장교의 내풍안정성을 검토하기위하여 3차원공탄성 모형을 제작하고 풍동실험을 수행하였다.(그림1 참조) 실험대상 구조물은 내풍안정성 증대를 위해 유선형 박스거더를 채용하고 케이블이 거더와 함께 비틀림에 저항하도록 2면 케이블을 적용하였다. 구조적인 측면에서는 보강형 자중감소를 위해 전경간을 강박스로 계획하였으며 측경간에 부반력제어를 위한 Counter Weight을 적용하였다. 실험대상 구조물은 완성계, 가설계95%, 가설계50%, 가설계45%로 모형을 해체하면서 진행하였고 가설단계 별로 내풍케이블의 수량과 형상을 달리하여 내풍안정성 개선효과를 확인하고자 하였다. 3차원 풍동실험 결과 완성계에서 교량의 안전성에 심각한 문제를 발생시킬 수 있는 와류진동, 플러터, 버페팅과 같은 유해한 진동현상이 발견되지 않았으며, 시공중 내풍안정성 확보를 위하여 대상교량에 내풍케이블을 설치하고 내풍케이블의 수량 및 배치형상에 따른 진동제어 효과를 검토하였다. 본 실험은 현재 풍동실험 요소기술을 이용하여 1,200m급 사장교 풍동실험을 수행하였고 이에 따라 교량이 초장대화 되면서 스케일다운에 따른 보강형질량, 케이블 간격 등 실험모형 제작상 문제점을 확인 할 수 있었으며 이러한 경험을 토대로 향후 1,000m 이상급 초장대 사장교 내풍설계를 위한 기초자료로 활용이 가능할 것으로 사료된다.

• Archives of design research
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• v.11
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• pp.1-9
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• 1995

Scandinavian design has special meaning in design history. Especially the Swedish designers have developed elegant and humane design style by combining the functionalism originated in Germany in the beginning of 20th century with their own crafts tradition. Now 'Swedish Modern' or 'Swedish Grace' is regarded as the most preferrable style for modern industrial society. American design as well as European design has been much changed under the influence of this democratic, simple and beautiful style. To find out the essential qualities of Swedish design style, I want to investigate the history of modern Swedish design and the design mechanism in Swedish corporates. Also I want to introduce the design education system in Sweden, which has contributed to developing contemporary Swedish design philosophy.

• Transactions of Materials Processing
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• v.28 no.1
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• pp.15-20
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• 2019

The superplastic forming/diffusion bonding process has been developed to fabricate a core frame structure with joint nodes out of tubes, for the development of a titanium high performance bicycle. The hydroforming process has been applied for bulging of a tube in the superplastic condition before, and during the diffusion bonding process. In this experiment, a commercial Ti-3Al-2.5V tube was selected as raw material for the study. The forming experiment has been performed using a servo-hydraulic press with a capacity of 200 ton. Next, nitrogen gas was used to acquire necessary pressure for the bulging and bonding of the tubes to fabricate the joint nodes. The pertinent processing temperature was $870^{\circ}C$ for the superplastic hydroforming/diffusion bonding (SHF/DB) process, using the Ti-3Al-2.5V tube. The bonding quality and the progress of bulging and diffusion bonding have been observed by the investigation of the joining interfaces at the cross section of the joint structure. The control of the nitrogen pressure throughout the SHF/DB process, was an important factor to avoid any significant defects in the joint structure. The whole progress stage of the diffusion bonding could be observed at a joint interface. A core structure with 5 joint nodes to manufacture a titanium bicycle could be obtained in a SHF/DB process.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.51-60
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• 2011

Purpose: This study was to investigate visual performance and subjective satisfaction with multifocal soft contact lenses at near works in university students. Methods: In a cross-over study design, 26 students (6 male, 20 female) who did not have any ocular disorder with at least 20/20(1.0) binocular vision were fitted with singlevision lenses (SofLens$^{TM}59$, Bausch + Lomb Co. USA) or multifocal lenses (SofLens Multifocal, Bausch + Lomb Co. USA). After 2 weeks, visual performance assessments included visual acuity, stereoacuity and contrast sensitivity function at distance and near. Near point of accommodation, accommodative facility, near point of convergence, vergence facility and near range of clear vision at near were examined. Students' satisfaction and preference were measured using survey questionaries. Results: Subjects maintained at least 20/20 binocular vision with multifocal and single-vision lenses at distance and near. There was no difference between multifocal and single-vision lenses in stereoacuity, contrast sensitivity function and vergence facility at far and near. The near point of accommodation, accommodative facility, near point of convergence and the near range of clear vision with multifocal lenses were better than single-vision lenses. On the survey questionaries, subjects reported that they preferred and satisfied with multifocal lenses with near works, and single-vision lenses with distance works. Conclusions: The majority of university students preferred multifocal to single vision lenses because multifocal lenses provided better visual performance at near works. This study suggests that multifocal lens is helpful for young adult in prolonged near works.

• Cartoon and Animation Studies
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• s.38
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• pp.53-70
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• 2015

In industrialized societies throughout the 19th and 20th centuries, Over Produced and Mass consumption images were constantly shown to people via Mass-Media as means to provoke one's desire. Frank Mouris, the American independent animator, captured and showed the infinite nesting of industrialized image with his autobiographical story through his work (1973) and made it as an intense visual flow. This innovative art animation has broke the traditional form of narrative animation and won the Annecy Animation Festival Grand Prix and the Academy Awards in 1974. This was also selected for preservation in the United States National Film Registry by the Library of Congress as being culturally, historically, or aesthetically significant in 1996. This study explores and shows that how these a-half million images to express Franks Mouris's autobiographical story in could be analyzed by the concept of Walter Benjamin's 'dialectical images'. Typically, the term 'dialectic' need to be formed by contradiction or opposite concept in the basic principles, but a dialectical image of Benjamin could be formed without any opposite concept while maintaining the uniqueness of each new relationship of the past. Benjamin's dialectical images are no longer stay in the historical past, It always meets with the present when someone realizes the past in the present moment. I suggest three different aspect according to Benjamin's point of view to analyse this animated film such as 'Historical-dialectical imaging of private/collective memory', 'Reconfiguring of present through analysing the relationship between the image flows and its own time/space', and 'Old future over the existing fragment and the presence of fragment. has the great value not only to present the experimental and innovative aesthetics of animated film, but also to show an analysis of contemporary culture and social aspect in mid-20th century. This study is to explore the diversity of animation representation, aesthetics, and also to suggest a new aspect of animation studies.

• Economic and Environmental Geology
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• v.45 no.1
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• pp.9-21
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• 2012

In this study, we investigated the chemical characteristics of soils collected from the several deserts and loess in China known as the typical source areas of Asian dust (the Taklamakan desert, the Alashan desert, the Ordos desert and the Loess Plateau). Based on our analysis, we examined the possibility of adverse effects on environments and human health. In each desert and loess, major elemental compositions of soils did not show large variations, implying that the long-periodic mixing of soils in each area made their chemical compositions homogeneous. Minor elements of soils in each desert and loess showed more complicated patterns with strong correlations each other (e.g., Cr, Cu, As, Co, Ni, V, Y, Sc, Sn, Pb, Zn, Cd, Cs, Li, Th, U). These results thus enable us to discriminate the soil of the Loess Plateau from those of the other deserts in China. The results of sequential extraction experiments for soils showed that the chemical speciation of Fe was dominant in residual fraction (>85%) in all deserts and loess, but the fractions of Mn and Ca chemical speciations were very different in each area. In the case of Mn, the fraction of amorphous Fe-Mn hydroxides (55.4%) in the Central Loess Plateau and the carbonate fraction (33.8%) in Taklamakan desert were higher as much as 2 to 5 times than other deserts. The chemical speciations of Ca are dominant in carbonate fraction in Taklamakan (75.9%) and Alashan (50.5%) deserts, but carbonate fractions of Ca in the Loess Plateau and Ordos deserts were low (6.6% and 2.1%, respectively). According to the mobility of trace elements inferred from the results of sequential extraction procedure, we could classify them into five groups, and the mobility of Cd, Pb and Cu are more than 87%, 33% and 30%, respectively. Therefore, Cd, Pb and Cu in soils of deserts and loess could be easily dissolved when interacted with surface water. As such, they could give adverse effects on surficial environments and human health.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.3
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• pp.183-188
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• 2011

According to increased multimedia data(i.e., MPEG video stream) in mobile application, protecting data becomes an important problem in the multimedia data delivery. SECMPEG is a selective encryption approach for protecting multimedia data. However, the computational overhead of SECMPEG's security level 3 is quite large because it encrypts the whole I-frames whose size is relatively larger than P/B-frames. Therefore, we need to analyze the characteristics of MPEG2 standard and derive an effective encryption of the I-frames. In this paper, we propose a slice-level, selective encryption approach by using the error-propagation characteristics of I-frames by a receiver. Our experimental results show that the proposed approach can reduce the execution time of SECMPEG's security level 3 by a factor of 30 without degradation of the security.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.5
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• pp.203-211
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• 2023

For fast-built and safe precast concrete (PC) construction, the dry mechanical splicing method is a critical technique that enables a self-sustaining system (SSS) during construction with no temporary support and minimizes onsite jobs. However, due to limited experimental evidence, traditional wet splicing methods are still dominantly adopted in the domestic precast industry. For PC beam-column connections, the current design code requires achieving emulative connection performances and corresponding structural integrity to be comparable with typical reinforced concrete (RC) systems with monolithic connections. To this end, this study conducted the standard material tests on mechanical splices to check their satisfactory performance as the Type 2 mechanical splice specified in the ACI 318 code. Two PC beam-column connection specimens with dry mechanical splices and an RC control specimen as the special moment frame were subsequently fabricated and tested under lateral reversed cyclic loadings. Test results showed that the seismic performances of all the PC specimens were fully comparable to the RC specimen in terms of strength, stiffness, energy dissipation, drift capacity, and failure mode, and their hysteresis responses showed a mitigated pinching effect compared to the control RC specimen. The seismic performances of the PC and RC specimens were evaluated quantitatively based on the ACI 374 report, and it appeared that all the test specimens fully satisfied the seismic performance criteria as a code-compliant special moment frame system.