• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.620-625
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• 2001

The pulpectomy or root canal treatment on primary teeth is to be done when there is evidence of chronic in flammation or necrosis in the radicular pulp. Due to the tortuous and ribbon-shaped anatomy of the primary teeth, the instrumentation of endodontic hand files and barbed broaches is not an easy procedure. Recently, many automatic Ni-Ti rotary instruments have been developed and has made endodontic treatment easier and faster. This report describes two cases of root canal treatment on primary molars using Ni-Ti rotary files. The cervical constricture was eliminated by the crown-down method, as smaller file proceeded unhindered into the apical third of the canal. In addition, the crown-down technique enhanced the efficacy of the endodontic irrigant. The use of rotary instrumentation for primary teeth seemed to be a more effective way to debride the uneven walls of primary teeth.

• 한국HCI학회:학술대회논문집
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• 2008.02c
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• pp.150-151
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• 2008

With the proliferation of vehicles and advancement of Information Technology, the technology of Telematics, which provides valuable services to people by collecting and analyzing the information from drivers, vehicles and Telematics environments (e.g. traffic information, road condition, weather information, etc.), has been a hot research area in IT and automotive recently. As the information technology revolution brings more and more assistance for driver information processing becomes increasing important. Therefore, drivers' workload is very essential factor for safety driving in Telematics environment. For managing drivers' workload effectively, ETRI haven been developing vehicle and driver management system which can collect data from drivers and vehicle in realtime and analyze the data to manage drivers' and vehcles' status since 2007. This technology will apply to commercial vehicle telematics such as texi or truck management system in the future for increasing driving safety. In this presentation, I would like to explain what we had developed so far and discuss future direction.

• Journal of the Korean earth science society
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• v.33 no.6
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• pp.497-509
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• 2012

The Gochanggun Kwangseungri macro-tide open-coast beach, located in the southwestern coast of Korea, was investigated in terms of the seasonal variations of surface sediment facies and sedimentary environment. Surface sediments of 45 sites in four seasons (May 2006 - February 2007) were sampled along three survey lines (15 sites in each survey line). The surface sediments of the Kwangseungri Beach are mainly composed of fine-grained sands, and its mean grain size is the coarsest in winter. Mud facies partly exists in summer, whereas it is nearly absent in winter. The spatial distribution of surface sediments shows a coast-parallel band of fine and medium sands during spring, fall, and winter. In the northern part, the study area is dominated by fine sands during summer, whereas by coarse sands during winter. These results can be interpreted that tide is more effective than wave on the surface sediment distribution of the Kwangseungri Beach during the summer season.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.973-984
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• 1999

This paper presents a method of moments with the transmission line theory to analyze the sleeve dipole array antennas and analyses characteristics of that. There were several considerations for analysis of the method of moments. First, the method of moments were applied at both of the sleeve dipole elements and the coaxial line because the current flows on both of them. Second, the feed voltages of each sleeve dipole element were obtained by using a transmission line theory because the feeding structure is fed by coaxial line in series. Third, the series reactance between the coaxial line and the open side of the sleeve was considered as impedance loading on the antenna. The radiation patterns and current distributions from the numerical results were considered as variation of the feed distances and frequencies. To verify the validity of our method, 4 elements sleeve dipole array antennas with 1 λg distance were fabricated and measured, and then the measured radiation patterns were compared with the numerical results. The measured results were confirmed a good agreement with the numerical results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.91-96
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• 2004

An optimal design of the gas generator for Liquid Rocket Engine (LRE) was conducted. A fuel-rich gas generator in open cycle turbopump system was designed for 10ton in thrust with RP-1/LOx propellant. The optimal design was done for maximizing specific impulse of thrust chamber with constraints of combustion temperature and for matching the power requirement of turbopump system. Design variables are total mass flow rate to gas generator, O/F ratio in gas generator, turbine injection angle, partial admission ratio, and turbine rotational speed. Results of optimal design provide length, diameter, and contraction ratio of gas generator. And the operational condition predicted by design code with resulting configuration was found to maximize the objective function and to meet the design constraints. The results of optimal design will be tested and verified with combustion experiments.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.174-174
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• 2012

최근 농업용저수지의 경우 기상이변에 따른 수위조절을 위하여 다량의 수문을 일시에 개방하는 사례가 지역적으로 증가하고 있는 추세이다. 그에 따라 당초 목적인 농업용수를 위한 취수시설이 최근 홍수조절용으로 활용됨에 따른 취수시설 내 공동현상이 발생하고 있다. 이러한 공동현상으로 인해 수시설물의 안정성에 문제가 발생하고 그에 따른 2차 재해위험이 있을 수 있다. 따라서 본 연구에서는 공동현상 방지를 위해 취수시설 공기관 설계기준에 대하여 고찰하였다. 공동현상을 방지하고 홍수량을 적절하게 배제하기 위해서 유입되는 공기량산정식이 필요하다. 공기관 단면결정은 농업생산기반정비사업 설계기준(필댐)의 구조설계 부분에 정리되어 있지만 이는 이수측면에서 설계 및 시공이 진행됨에 따라서 취수에 대한 목적을 달성하기에는 어려움이 있다. 따라서 취수시설의 기능과 역할을 증대시키고자 취수시설 적정 공기관 설계를 분석하여 향후 신규, 개보수 및 현장 유지관리에 활용하기 위한 기초자료를 제시하였다. 이러한 공동현상 및 공기관 설계를 위하여 현장조사, 수치해석, 수리모형시험을 병행하여 문석하였다. 그 결과 취수탑의 형상변수와 수위에 대한 수치해석을 수행하여 변수가 소요공기량에 미치는 영향은 조절게이트 개폐율을 증가시킬수록 소요공기량이 증가하며, 약 80%의 개폐율에서 소요공기량이 최대가 되었다. 방수로 직경이 증가하면, 공기관 입구와 끝단의 압력차가 감소하여 소요공기량이 감소하고, 수위가 증가하면 소요공기량이 증가하는 것으로 분석되었다. 따라서 공동현상 방지를 위해 공기량 산정식은 취수터널에 연직수문이 설치되어 있는 6가지 흐름의 형태에 따라서 $/Q_w=0.04(F-1)^{0.85}$, $Q_a/Q_w=K(F-1)$, $Q_a/Q_w=0.014(F-1)^{1.4}$, $Q_a/Q_w=0.015(F-1)^{1.4}$의 관계식 중 적정한 것을 사용하여야 할 것으로 판단되며, 또한 공기관에 유입부의 허용부압은 수두로부터 1.0m이하로 하고, 공기관 내 풍속은 $45^m/s$를 기준으로 최대 $90^m/s$로 하여야 할 것으로 판단된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2689-2694
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• 2014

This study analyze the impact of omija(maximowiczia chinensis) market by Korea-China FTA and review the change of mid and long term supply-demand from 2014 to 2018. A scenario is also imported to simulate and measure the impacts of the Korea-China FTA. The scenario is that tariff rates for Chinese product(omija) will be zero after 5 years from 2014. A partial equilibrium model of Omija is specified to forecast mid and long term supply-demand and prices. Equations in the model were estimated by using econometric techniques. The results based on scenario are compared with the results by the baseline case(maintenance of current situation). Our study show that when the tariff rates for Chinese product(Omija) will be zero after 5 years from 2014, the cultivated area of Omija is forecasted to decline until 3,370ha in 2018, and the consumption is forecasted to increase up to 12,040.8MT in 2018, and also total revenue of about 9.8 billion korean won will be decreased during 5 years(2014-2018).

• Journal of Korean Philosophical Society
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• v.142
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• pp.165-192
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• 2017

The purpose of this thesis is to explain the difference between Heidegger's hermeneutical philosophy and Gadamer's philosophical hermeneutics. The difference is to say that Heidegger's philosophy begins with Aristotle's theory of category and transcendental philosophy. On the other hand, the beginning of Gadamer's philosophical research is Plato's dialog, philosophy and Hegels dialectic. 2. Heidegger regards humanism as a variant of the modern ideal of human beings. On the contrary, Gadamer understands humanism as a place where romantism leads to the ideals of human education. 3. Heidegger says that the hermeneutical circle is still a logical and existential structure of the circle. On the contrary, Gadamer understands the circle as a circle between the whole and the part. This circle is the law of traditional hermeneutics derived from the tradition of rhetoric. 4. Heidegger says Plato's philosophy is the first beginning of the substance metaphysic, Hegel's philosophy the end of the subject metaphysic. On the contrary, Gadamer says the hermeneutical understanding and the hermeneutical interpretation is endless. 5. Heidegger's ontology is as Sein zum Tode a future oriented and eschatological. On the contrary, Gadamer's hermeneutic is as Sein zum Text always the way to a past, the infinite openness.

• Journal of The Geomorphological Association of Korea
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• v.19 no.4
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• pp.139-155
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• 2012

Most of previous landform classification methods using DEM compares the values between the center of the cell and the surrounding cells, which in turn, greatly depends on analysis scale. To overcome the problem of scale-dependency, a new classification scheme is developed, which is called "Geomorphons". Unlike the traditional approaches using DEM, Geomorphons is the way which compares the level with other cells against the criteria cell. As a pilot study, we classify the landforms of Pyeongchang-Gun in Korea. Then, we compare the result with the other methods such as Topographic Position Index. Through the systematic analysis, we obtain the following findings. First, Geomorphons can reduce the time for the classification of landforms because of using unsupervised classification. Second, Geomorphons is little dependent on change in the scale, which can provide a pilot tool for reconnaissance study for covering large area.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.44-44
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• 2018

조류(녹조)발생과 대응 연차보고서(2016)에 따르면, 낙동강 유역의 녹조현상은 2013년부터 해마다 발생했으며 국가적으로 가장 극심한 가뭄을 겪은 2015년의 경우 최장 161일 동안 지속되었음을 보고하였다. 이러한 녹조대응을 위해 환경부 국토부 등 관계기관은 댐 보 연계운영협의회 등을 통해 2016년 8월부터 낙동강 일부 댐 및 보에 대해 부분 방류를 실시하였다. 댐-보 연계운영에 따른 수문 수질 거동 분석은 국가 유역관리 측면에서 우선적으로 대비해야 할 중요한 문제이나, 댐보 연계의 효율적인 운영을 위한 정확한 분석과 평가에 대한 연구가 체계적으로 이뤄지고 있지 않은 실정이다. 본 연구에서는 낙동강유역($2,369km^2$)을 대상으로 SWAT(Soil and Water Assessment Tool)을 이용하여 지표수와 지하수의 상호작용에 의한 물수지 분석을 수행하고, 수질(SS, T-N, T-P)을 모의하였다. SWAT 모형 구축을 위해 낙동강유역을 표준유역 단위로 구분하고, 기상자료, 다목적댐(안동댐, 임하댐, 합천댐, 남감댐, 밀양댐)과 다기능보(상주보, 구미보, 칠곡보, 강정보, 달성보, 합천보, 함안보) 운영자료, 국가지하수정보센터에서 관측 및 관리하고 있는 지하수위 관측자료, 국가수질측정망 하천수 수질 측정자료를 수집하였다. SWAT 모형의 신뢰성있는 수문 및 수질 보정을 위해 낙동강유역 내 위치하는 다목적댐 및 다기능보의 실측 방류량을 이용하여 댐 운영모의를 고려하였고, 지하수위, 토양수분 및 수질자료를 이용하여 모형의 시공간적 보정(2005~2009)과 검증(2010~2017)을 실시하였다. 댐-보 연계운영 평가를 위해 환경부에서 제시한 4개의 연계운영 시나리오 중 3개의 시나리오((1) 댐+보 동시방류+제약수위 유지, (2) 보 동시방류+제약수위 유지, (3) 보 순차방류+제약수위 유지)를 선택하여 모의하였으며, 시나리오에 따른 수문 수질 거동을 분석하였다.