• 한국자동차공학회논문집
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• 제10권5호
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• pp.45-57
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• 2002

In this paper, the results gained by applying many impingement models to the cylinder and flat plate were analyzed in comparison with the experimental data to study a spray/wall interaction phenomena. To begin with, the behavior of spray injected normal to the wall was analysed using three different impingement models ; Naber and Reitz model(NR model), Watkins and Wang model(WW model) and Park and Watkins model(PW model) in the present calculation. The results obtained from these models were compared with experimental data of Katsura et. al. The results indicated that PW model was in better agreement with experimental data than the NR and WW model. Also f3r spray injected at 30DEG , the result of three models were compared with experimental data of Fujimoto et. al. The results showed that m model overpredicted the penetration in the radial direction because this model was based on the inviscid jet analogy. WW model did not predicted the radius and height of the wall spray effectively. It might be thought that this discrepancy was due to the lack of consideration of spray film velocity occurred at impingement site. The result of PW model agrees with the experimental data as time goes on. In particular, a height of the spray droplets was predicted more closely to the experimental data than the other two models. The results of PW model in which the spray droplets were distributed densely around the edge of droplet distribution shaped in a circle had an agreement with the experimental data of Fujimoto et. al. Therefore, it was concluded that PW model performed better than M and WW model for prediction of spray behavior. The numerical calculation using PW model performed to the cylinder similar to the real shape of DI engine. The results showed that vortex strength near the wall in the cylinder was stronger than that in the case of flat plate. Contrary to the flat plat, an existence of the side wall in the cylinder caused the tangential velocity component to be reduced and the normal velocity component to be increased. The flow tends to rotate to the inside of cylinder going upward to the right side wall of cylinder gradually as time passes. Also, the results showed that as the spray angle increases, the gas velocity distribution and the tumble flow seemed to be formed widely.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 3차
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• pp.72-77
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• 2010

The Incheon Bridge, which was opened to the traffic in October 2009, is an 18.4 km long sea-crossing bridge connecting the Incheon International Airport with the expressway networks around the Seoul metropolitan area by way of Songdo District of Incheon City. This bridge is an integration of several special featured bridges and the major part of the bridge consists of cable-stayed spans. This marine cable-stayed bridge has a main span of 800 m wide to cross the vessel navigation channel in and out of the Incheon Port. In waterways where ship collision is anticipated, bridges shall be designed to resist ship impact forces, and/or, adequately protected by ship impact protection (SIP) systems. For the Incheon Bridge, large diameter circular dolphins as SIP were made at 44 locations of the both side of the main span around the piers of the cable-stayed bridge span. This world's largest dolphin-type SIP system protects the bridge against the collision with 100,000 DWT tanker navigating the channel with speed of 10 knots. Diameter of the dolphin is up to 25 m. Vessel collision risk was assessed by probability based analysis with AASHTO Method-II. The annual frequency of bridge collapse through the risk analysis for 71,370 cases of the impact scenario was less than $0.5{\times}10^{-4}$ and satisfies design requirements. The dolphin is the circular sheet pile structure filled with crushed rock and closed at the top with a robust concrete cap. The structural design was performed with numerical analyses of which constitutional model was verified by the physical model experiment using the geo-centrifugal testing equipment. 3D non-linear finite element models were used to analyze the structural response and energy-dissipating capability of dolphins which were deeply embedded in the seabed. The dolphin structure secures external stability and internal stability for ordinary loads such as wave and current pressure. Considering failure mechanism, stability assessment was performed for the strength limit state and service limit state of the dolphins. The friction angle of the crushed stone as a filling material was reduced to $38^{\circ}$ considering the possibility of contracting behavior as the impact.

• 대한수학교육학회지:수학교육학연구
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• 제23권3호
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• pp.313-333
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• 2013

본 연구는 초 중등 수학교사의 '다문화역량' 실태를 파악하고 이를 바탕으로 수학교과에서 다문화교육을 실천할 수 있는 역량 함양을 위한 다문화교사교육의 방향을 제안하고자 한다. 이를 위해 이론적 검토 및 통계적 검증을 거쳐 5점 척도의 '수학교사의 다문화역량 측정도구'를 구성하고 서울, 경기, 인천 지역의 초 중등 수학교사 309명을 대상으로 설문조사를 실시하였다. 그 결과 수학교사들의 다문화역량 평균은 2.636(표준편차 .290)로 조사되었고 다문화와 관련한 일반적인 지식 및 신념을 묻는 범주A와 비교하여 수학교과의 특성이 반영된 범주 B, C, D의 평균이 낮다는 것을 확인할 수 있었다. 또한 집단별 비교를 위한 분산분석 결과 '교사의 경력', '다문화교사 교육 이수 여부', '다양한 배경의 사람들에 대한 간접 접촉 경험 여부'에 따른 집단별 차이가 없는 반면, '다양한 문화적 배경의 사람들과 직접 접촉 경험 여부', '교사의 전공'에 따라 다문화역량이 집단별 유의한 차이가 있는 것으로 조사되었다. 이와 같은 결과를 바탕으로 수학교과를 통해 다문화교육을 수행할 수 있도록 실천적 맥락의 다문화교사교육에 대한 시사점을 논의하였다.

• 기술혁신학회지
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• 제14권2호
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• pp.343-372
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• 2011

한국 영화는 개화기에 도입된 이후 현재 세계적으로 호평 받는 수준으로 발전하였으며 산업적으로도 큰 성장을 이루었다. 그러나 최근 디지털시네마 및 입체영화의 등장 등 급진적 기술이 등장함에 따라 해외 기술의 도입 위주로 진행되던 기술 전략 정책에 변화가 요구되고 있다. 이에 본 논문은 영화산업의 기술혁신에 초점을 두고 한국 영화산업의 기술혁신체제를 분석한다. 영화산업 관련 기존 문헌 분석과 전문가 인터뷰를 통해 한국 영화산업의 기술 및 지식, 제도, 혁신주체와 네트워크를 조망해 보며, 이를 통해 한국 영화산업 기술학신체제의 특정과 문제점을 규명하는 것이 본 논문의 목적이다. 연구결과 영화산업 기술혁신의 한국적 특정을 규명하였으며, 지식 축적 과정의 단절, 영화산업 특수적 연구개발 활동의 부재, 혁신주체의 전문성 결여 등과 같은 문제점도 도출할 수 있었다. 이를 바탕으로 본 논문에서는 영화산업 기술혁신을 위한 정책적 함의를 제공한다. 또한 본 논문은 기술혁신연구 분야에 영화산업을 소개함으로써 새로운 연구 기회를 제공한다는 의의도 갖는다.

• 기술혁신학회지
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• 제20권4호
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• pp.939-969
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• 2017

환경과 안전에 대한 관심이 증가함에 따라 사회적 규제 및 이의 혁신에 대한 영향성에 대한 관심 또한 증대되고 있다. 포터가설을 중심으로 한 기존의 사회적 규제 관련 문헌들은 주로 혁신으로 인한 비용, 기대이익, R&D 투자 등 내적 요소에 초점을 두어 왔다. 최근에는 환경규제 등 사회적 규제로 인한 산업구조의 변화에 관심을 두는 연구가 증가하고 있는 상황이나, 사회적 규제에 따른 외부환경의 변화와 그로 인한 혁신에 대한 영향에 대해서는 연구가 많이 이루어지지 못한 상황이다. 이에 본 연구에서는 기존 문헌이 제시하는 바와 같이 준수 기대이익 등 내적 요인은 물론, 산업구조 변화와 같은 변화를 통해 사회적 규제가 혁신에 영향을 미칠 수 있음을 보여주고자 하였다. 이를 위해 본 연구에서는 국내 철강 구조물용 내화 피복재 산업의 사례연구를 실시하였다. 연구 결과 내화 피복재 산업은 1990년대 3번에 걸친 규제완화를 경험하였으며, 이들 규제 완화들이 시장 기회 및 기대이익을 제공함으로써 신규 시장진입을 유도하였고, 시장구조 변화와 경쟁 심화에 따라 기업들의 혁신이 발생하였음을 확인할 수 있었다.

• Journal of Astronomy and Space Sciences
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• 제30권4호
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• pp.269-277
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• 2013

In this study, we present results of precise orbital geodetic parameter estimation using satellite laser ranging (SLR) observations for the International Laser Ranging Service (ILRS) associate analysis center (AAC). Using normal point observations of LAGEOS-1, LAGEOS-2, ETALON-1, and ETALON-2 in SLR consolidated laser ranging data format, the NASA/GSFC GEODYN II and SOLVE software programs were utilized for precise orbit determination (POD) and finding solutions of a terrestrial reference frame (TRF) and Earth orientation parameters (EOPs). For POD, a weekly-based orbit determination strategy was employed to process SLR observations taken from 20 weeks in 2013. For solutions of TRF and EOPs, loosely constrained scheme was used to integrate POD results of four geodetic SLR satellites. The coordinates of 11 ILRS core sites were determined and daily polar motion and polar motion rates were estimated. The root mean square (RMS) value of post-fit residuals was used for orbit quality assessment, and both the stability of TRF and the precision of EOPs by external comparison were analyzed for verification of our solutions. Results of post-fit residuals show that the RMS of the orbits of LAGEOS-1 and LAGEOS-2 are 1.20 and 1.12 cm, and those of ETALON-1 and ETALON-2 are 1.02 and 1.11 cm, respectively. The stability analysis of TRF shows that the mean value of 3D stability of the coordinates of 11 ILRS core sites is 7.0 mm. An external comparison, with respect to International Earth rotation and Reference systems Service (IERS) 08 C04 results, shows that standard deviations of polar motion $X_P$ and $Y_P$ are 0.754 milliarcseconds (mas) and 0.576 mas, respectively. Our results of precise orbital and geodetic parameter estimation are reasonable and help advance research at ILRS AAC.

• 한국농공학회지
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• 제8권1호
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• pp.1011-1034
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• 1966

This thesis is the final report which has long been studied by the author to obtain the design basis for various hydrological constructions with the specific system suitable to the natural environmental conditions in Korea. This report is divided into two parts: one is to estimate runoff volume from watersheds and the other to estimate the peak discharge for a single storm. According to the result of observed runoff record from watersheds, it is known that Kajiyama formula is useful instrument in estimating runoff volume from watersheds in this country. But it has been found that this formula shows us 20-30% less than the actual flow. Therefore, when wihed to bring a better result, the watershed characteristics coefficient in this formula, that is, f-value, should be corrected to 0.5-0.8. As for the method to estimate peak discharge from drainage basin, the author proposes to classify it in two ways; one is small size watershed and the other large size watershed. The maximum -flood discharge rate $Q_p$ and time to peak Pt obtained from the observed record on the small size watershed are compared by various methods and formulas which are based upon the modern hydrological knowledge. But it was fou.d that it. was not a satisfied result. Therefore, the author proposes. tocomputate $Q_p$, to present 4.0-5.0% for the total runoff volume ${\Sigma}Q$.${\Sigma}Q$ is computed under the assumption of 30mm 103s in watershed per day and to change the theoritical total flow volume to one hour dura tion total flow rate when design daily storm is given. Time to peak Pt is derived from three parameters which are u,w,k. These are computed by relationship between total runoff volume (ha-m unit)and $Q_p$. (C.M.S. unit). Finally, the author checked out these results obtained from 51 hydrographs and got a satisfied result. Therefore the author suggested the model of design dimensionless unit-hydrograph. And the author believes that this model will be much available at none runoff record river site. In the large size watersheds in Korea when the maximum discharge occurs, the effective rainfall is two consequtive stormy days. So the loss in watershed was assutned as 6Omm/2days,and the author proposed 3-hour-daration hydrograph flow distribution percentage. This distribution percentage will be sure to form the hydrograph coordinate.

• 한국도로학회논문집
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• 제9권3호
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• pp.111-121
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• 2007

지난 2005년 12월 호남지역에 내린 폭설과 연이은 한파로 서해안고속도로와 호남고속도로에 많은 피해가 보고되었다. 특히 2.0m 이하의 저토피고를 갖는 통로 암거 상부의 포장에 최대 6.0cm 높이의 노면 융기와 횡방향 균열이 발생하였다. 이는 포장의 수명단축 및 공용성 저하, 교통사고 발생 등에 영향을 미치기 때문에 시급한 대책마련이 요구되었다. 현장 조사 결과 단기간에 증가한 침투수가 노상과 노체에 함유된 세립분의 영향으로 포장 내부의 배수가 지연되고 저온에서 발생한 동상이 포장 파손의 일차적인 원인으로 지적되었다. 최근 한국도로공사는 도로교통기술원과 공동연구를 통해서 신설되는 암거상부 포장에 대한 새로운 설계안을 제시하였다. 본 설계안은 암거 상단부에 맹암거를 설치하여 침투수의 원활한 배수를 유도하고 간극수압의 저감을 통해 포장하부의 동상을 예방하고자 한다. 본 논문에서는 위의 설계법 개발을 위해서 수행한 실험과 수치해석결과를 다루고 있다. 현장에서 채취한 지반시료에 대한 점토함유량 분석을 실시하고 2차원 유한요소해석을 실시하여 골재 입경에 따른 침투류의 배수특성을 조사하였다. 저토피고(2.0m 이하) 암거 상부 포장에 적용될 맹암거의 규격은 침투류 해석결과와 현장 시공성을 고려하여 폭과 높이를 각각 400mm, 800mm로 결정하였다.

• 한국운동역학회지
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• 제26권4호
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• pp.343-351
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• 2016

Objective: The purpose of this study was to help improve game performance and provide preliminary data to enhance the efficiency of the kick and stability of the support foot by comparing the kinematic characteristics of the repeated side kick (geodeupyeopchagi) in poomsaeKoryo between expert and non-expert groups. Method: The subjects were divided into 2 groups according to proficiency in Taekwondo, an expert group and a non-expert group (n = 7 in each group), to observe the repeated side-kick technique. Four video cameras were set at a speed of 60 frames/sec and exposure time of 1/500 sec to measure the kinematic factors of the 2 groups. The Kwon3D XPprogramas used to collect and analyze three-dimensional spatial coordinates. Ground reaction force data were obtained through a force plate with a 1.200-Hz frequency. An independent samplesttest was performed, and statistical significance was defined as .05. The SPSS 18.0 software was used to calculate the mean and standard deviation of the kinematic factors and to identify the difference between the experts and non-experts. Results: The angular displacement of the hip joint in both the expert and non-expert groups showed statistical significance on E1 and E4 of the left support foot and E5 of the right foot (p<.05). The angle displacement of the knee joint in both groups showed statistical significance on E4 of the left support foot, and E1 and E2 of the right foot (p<.05). The angular velocity of the lower leg in both groups showed no statistical significance on the left support foot but showed statistical significance on E2 and E6 of the right foot (p<.05). The angular velocity of the foot in both groups showed no statistical significance on the left support foot but showed statistical significance on E2 of the right foot (p<.05). The vertical ground reaction force in both groups showed statistical significance on E2 (p<.05). The center of pressure in all directions in both groups showed statistical significance (p<.5). Conclusion: While performing the repeated side kick (geodeupyeopchagi), the experts maintainedconsistency and stability of the angle of the support leg while the kick foot moved high and fast. On the other hand, the angle of the support foot of non-experts appeared inconsistent, and the kick foot was raised, relying on the support leg, resulting in unstable and inaccurate movement.

• 한국유기농업학회지
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• 제26권1호
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• pp.141-149
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• 2018

This experiment was conducted to investigate the effects of multi-enzyme on growth performance, intestinal morphology, and nutrient digestibility of weaned pigs. A total 36 weaned pigs ($5.92{\pm}0.48kg\;BW$; 28 d old) were randomly allotted to 2 dietary treatments (3 pigs/pen, 6 replicates/treatment) in a randomized complete block design. The dietary treatments were a typical diet based on corn and soybean meal (CON) and CON with 0.1% multi-enzyme (Multi; mixture of ${\beta}-mannanase$, xylanase, ${\alpha}-amylase$, protease, ${\beta}-glucanase$, and pectinase). Pigs were fed their respective diets for 6 wk. Measurements were growth performance, morphology of ileum, apparent ileal digestibility and apparent total tract digestibility of dry matter, crude protein, and energy of weaned pigs. There were no significant differences on growth performance during overall experimental period. No differences were found for the morphology of ileum and nutrient digestibility between CON and Multi groups. Therefore, the results in the current study indicated that multi-enzyme supplementation in diets had no effects on growth performance, intestinal morphology, and nutrient digestibility of weaned pigs.