• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.2
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• pp.105-112
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• 2000

In-Ceram system is one of contemporary esthetic all ceramic restorations and has relatively high flexural strength. The purpose of this study was to evaluate the marginal fit of In-Ceram crown according to shoulder width and measuring position. In this study, twenty seven In-Ceram crowns devided into three groups, each prepared with shoulder width of 0.6mm, 0.9mm and 1.2mm. All specimens were cemented with glass ionomer cement. After cementation, specimens were measured marginal gap between the margin of the In-Ceram crown and the finishing line of resin master die by using a refrective microscope. Marginal gaps were recorded at the labial, lingual, mesial and distal measuring points on the resin master die. The results of this study were as follows: 1. Mean marginal fits of each group were $81.28{\mu}m$ in 0.6mm shoulder width, $70.78{\mu}m$ in 0.9mm shoulder width and $67.75{\mu}m$ in 1.2mm shoulder width. 2. There was significant difference between group 0.6mm and 0.9mm, 1.2mm.(p<0.05). 3. In comparison of marginal fit according to the measuring points, there was no significant difference.

• Journal of the Korean Chemical Society
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• v.40 no.6
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• pp.445-452
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• 1996

Catalytic hydrogenation of ketones and aldehydes by RuH(NO)$L_3$ ($L_3$: $PPh_3$, PhP($CH_2CH_2PPh_2$)$_2$(etp)) was investigated to examine the reaction mechanism and the competence of hydridonitrosyl complexes as catalysts for organic synthesis. RuH(NO)$L_3$ showed catalytic activity for the hydrogenation and the activities of catalysts were dependent on the steric and electronic factors. The less the steric demands of the substrates become, the more activity the catalysts show. For the electronic effect, the more the partial positive charge on the carbonyl carbon atom in ketones becomes and the more the double bond character of carbonyl group in aldehydes becomes, the more active the catalysts are. These results reflect the difference of reaction mechanisms of two substrates, ketones and aldehydes. Catalytic activities of RuH(NO)(etp) and RuH(NO)($PPh_3$)$_3$ in the presence of extra $PPh_3$ toward hydrogenation showed the existence of a reaction pathway accompanied with the change of the bonding modes of NO ligand. The roles of excess $PPh_3$ change with increase of the mole ratio of $PPh_3$ to catalysts; prevention of ligand dissociation from comlexes → bases → ligands. The activity of RuH(NO)(etp) was lower than that of RuH(NO)($PPh_3$)$_3$ toward the hydrogenation of the same substrates mainly due to the structural difference. These catalysts showed the selectivity toward olefin hydrogenation over carbonyl groups in the competitive reaction.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.125-135
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• 1993

The safe and efficient operation of nuclear plants is recognized to be accomplished through the application of plant automation using digital technology, which is one of main targets of the next generation nuclear plants. For plant level automation, it is first required that each major subsystem be digitalized, and the steam generator water level control system is discussed in this study. The transfer functions between inputs and the level are derived by employing the thermal hydraulic model of the steam generator and are applied to the analysis of the current three-element control system. Since the control scheme in this study includes the steam generator itself as a process plant, the system order is high and the numerical instability arises in digitalizing. Together with this, the unreliability of the feedwater feedback signal at low power level leads to the proposal of a two-element control system with a proper digital controller. The digital PI controller developed for this system has the initial power adaptive gain and integration time constant. And it makes the overall system response satisfy the stability and other necessary control specifications simultaneously. Since the two-element control system using this controller depends on the initial power only, it is simple to define and it shows a similar level response behavior to that of its corresponding analog system.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.350-354
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• 1982

These studies were conducted to evaluate the milling characteristics of Korean wheat cultivars and breeding lines harvested in 1980 and 1981. The straight-grade flour yield (by Buhler experimental mill) for all tested wheats was in a range of 56 to 73% with a mean value of 65% and the flour ash content averaged 0.44%. Mean milling score for all tested wheats was about 78. Average ash values of wheats harvested in 1980 and 1981 were 665.3 and 683.5, respectively, and flour protein content averaged 10.55% and 10.25%, respectively. There were significant positive correlations between flour yield vs. milling score, ash content vs. ash value and protein content vs. ash value, while there were negative correlation between flour ash vs. milling score, protein content vs. milling score and milling score vs. ash value.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.260-265
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• 1999

멀티빔 음향측심기(Multibeam Echo Sounder)는 기존의 단빔 음향측심기(Singlebeam Echo Sounder)와 달리 탐사선 진행방향의 수직(Crosstrack)으로 해저면을 주사(Swath)하여, 한 번의 송수신(Ping)으로 다중의 빔 자료 - 수심, 후방산란된 음압(Backscattered Amplitude), 사이드 스캔 소나(Side Scan Sonar) 자료 - 를 취득하는 장비이다. 멀티빔 음향 측심기를 이용한 해저면 탐사의 경우, 수심이 변함에 따라 주사폭(Swath width)이 변화하고, 각 빔의 수평 해상도(Footprint)는 수심과 더불어 빔폭(Beam width)에 의하여 동적으로 변화한다. 멀티빔 음향 측심기는 해저면을 전역탐사 할 수 있을 뿐만 아니라, 연속된 음향 탐사를 통하여 이웃한 핑 사이에 발생하는 전방중첩영역(Endlap)과 이웃 측선(Trackline)을 따라 겹쳐지는 측방중첩영역(Sidelap)의 자료들을 이용하여 멀티 뎀 자료들의 전반적인 정확도 및 신뢰도를 평가할 수 있다. 본 논문은 수로 측량(Hydrographic Survey)에서 사용되는 멀티빔 음향 측심기를 운영하여 얻어진 측심 자료를 처리하는 알고리즘 개발에 관한 연구이다. 본 논문에서는 L3사의 Sea Beam 2100 벌티빔 음향 측심기를 대상으로, 멀티빔의 측심 원리와 해저 지형에 대한 일반적 이해를 통하여 획득된 측심 자료의 통계적 특성을 파악하고, 오측심된 수심 자료를 제거하는 방법을 제안하며, 측심 구간의 대표격자 크기를 결정하는 기준을 제시한다. 또한, 항공원격탐사에서 고도 추정시 사용되고 있는, 평균보간법, 가중평균 보간법과, 본 논문에서 제안하는 격자 대표값 선정 알고리즘(Gridding Algorithms)의 결과를 비교하고, 최종적으로 얻어지는 해저 수치지형모델(DEM, Digital Elevation Model)과 후방산란 영상을 제시한다. 빠른 한지형잔디들이 지표면을 피복하도록 하고 여름의 고온기와 장마시기에는 뿌리전단력이 우수한 이러한 초종들로 지표면이 피복되도록 하는 것이 이상적이라 생각된다. 4. 혼파처리간의 토사유출량을 비교한 결과 토사 유출 억제효과는 한지형과 나지형잔디들의 혼합형(MixtureIII)과 자생처리구(MixtureV), Italian ryegrass와 자생식물의 혼합형(MixtureIV)등에서 비교적 낮은 수치를 토사유출량을 기록하였다. 이러한 결과는 자생식물들이 비록 초기생육속도는 외래도입초종에 떨어지지만 토사유출의 억제효과면에서는 이들 외래초종에 필적할 수 있음을 나타낸다고 할 수 있겠다.중량이 약 115kg/$m^2$정도로 나타났다.소 들(환경의 의미, 사람의 목적과 지식)보다 미학적 경험에 주는 영향이 큰 것으로 나타났으며, 모든 사람들에게 비슷한 미학적 경험을 발생시키는 것 이 밝혀졌다. 다시 말하면 모든 사람들은 그들의 문화적인 국적과 사회적 인 직업의 차이, 목적의 차이, 또한 환경의 의미의 차이에 상관없이 아름다 운 경관(High-beauty landscape)을 주거지나 나들이 장소로서 선호했으며, 아름답다고 평가했다. 반면에, 사람들이 갖고 있는 문화의 차이, 직업의 차 이, 목적의 차이, 그리고 환경의 의미의 차이에 따라 경관의 미학적 평가가 달라진 것으로 나타났다.corner$적 의도에 의한 경관구성의 일면을 확인할수 있지만 엄밀히 생각하여 보면 이러한 예의 경우도 최락의 총체적인 외형은 마찬가지로 $\ulcorner$순응$\lrcorner$의 범위를 벗어나지 않는다. 그렇기 때문에도 $\ulcorner$순응$\lrcorner$과 $\ulcorner$표현$\lrcorner$의 성격과 형태를 외형상으로 더욱이 공간상에서는 뚜렷하게 경계

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.578-586
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• 2005

Recently, due to the launch of digital broadcasting service, the demand of Flat Panel Display (FPD) is sharply rising. Among them, the PDP is expected to be one of the most promising digital displays of next generation because of its large screen size, high resolution, thinness and board field of view. Meanwhile, the PDP uses ADS (Address Display-period Separation) scheme which divide one subfield into address and sustaining period to express the grey scale of images. Since the output of sustaining power module Is mostly used for sustaining period, the load of the sustaining power module can be considered as a pulsating load. Due to this particular load condition, if the wide ZVS range of the power switches is not guaranteed, the hard switching causes large amount of switching loss and serious thermal problem in power module. In this paper, a high efficiency power conversion circuit for 60' PDP sustaining power module which achieves wide ZVS range with the help of additional ZVS tank is proposed. According to the various gating methods, the different operations of the proposed converter are presented. And, to confirm the properties of the proposed converter, an experimental prototype of 900W power converter is constructed md tested. As a result, more than $92\%$ of high efficiency is obtained at $10\%$ load condition, and the ZVS operation is achieved from full load to $10\%$ load condition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2C
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• pp.141-149
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• 2007

Associating the shoulder line with head location of the human body is useful in verifying, localizing and tracking persons in an image. Since the head line and the shoulder line, what we call ${\Omega}$-shape, move together in a consistent way within a limited range of deformation, we can build a statistical shape model using Active Shape Model (ASM). However, when the conventional ASM is applied to ${\Omega}$-shape fitting, it is very sensitive to background edges and clutter because it relies only on the local edge or gradient. Even though appearance is a good alternative feature for matching the target object to image, it is difficult to learn the appearance of the ${\Omega}$-shape because of the significant difference between people's skin, hair and clothes, and because appearance does not remain the same throughout the entire video. Therefore, instead of teaming appearance or updating appearance as it changes, we model the discriminative appearance where each pixel is classified into head, torso and background classes, and update the classifier to obtain the appropriate discriminative appearance in the current frame. Accordingly, we make use of two features in fitting ${\Omega}$-shape, edge gradient which is used for localization, and discriminative appearance which contributes to stability of the tracker. The simulation results show that the proposed method is very robust to pose change, occlusion, and illumination change in tracking the head and shoulder line of people. Another advantage is that the proposed method operates in real time.

• Journal of Energy Engineering
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• v.25 no.2
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• pp.37-44
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• 2016

The demand for electricity has a considerable impact on various energy sectors since electricity is generated from various energy sources. This paper attempts to estimate the electricity demand function and obtain some quantitative information on price and income elasticities of the demand. To this end, we apply a lagged dependent variable model to derive long-run as well as short-run elasticities using the time-series data over the period 1991-2014. Our dependent variable is annual electricity demand. The independent variables include constant term, real price of electricity, and real gross domestic product. The results show that the short-run price and income elasticities of the electricity demand are estimated to be -0.142 and 0.866, respectively. They are statistically significant at the 5% level. That is, the electricity demand is in-elastic with respect to price and income changes in the short-run. The long-run price and income elasticities of the electricity demand are calculated to be -0.210 and 1.287, respectively, which are also statistically meaningful at the 5% level. The electricity demand is still in-elastic with regard to price change in the long-run. However, the electricity demand is elastic regarding income change in the long-run. Therefore, this indicates that the effect of demand-side management policy through price-control is restrictive in both the short- and long-run. The growth in electricity demand following income growth is expected to be more remarkable in the long-run than in the short-run.

• Journal of Korea Technology Innovation Society
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• v.15 no.1
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• pp.129-162
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• 2012

This study analyzed the institutional characteristics of large scale national R&D policies in Korea. The analysis examined the continuity and change of the policy institution. It dealt with G7 Project, 21C Frontier Project, and Next Generation Growth Engine Project as the major large scale national R&D policies in Korea. The theoretical approach of this study is to the continuity and change or evolution of policy institution from the perspective of new institutionalism. Based on the theoretical analysis, it emphasized the analysis of the institutions in three different levels: macro, meso, and micro level. In the analysis, the research examined the idea of policy institution or policy goal, participants in the policy institution, and policy instruments in different levels. The outcome of the analysis shows that the policy of large scale national R&D in Korea has the institutional continuity in the macro level. In the meso level, however, the policy institution changes due to the administration change and the influence of political economic environment. In the micro level, the policy institution changes based on the symbolic influence of policy goal and the interest of bureaucrats. The research finds that the micro and meso level institutional changes cause the evolution of policy institutions and the major change of policy institution.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.2
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• pp.73-80
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• 2011

The radiation shielding analysis for a Burnup-credit (BUC) cask designed under the management of Korea Radioactive Waste Management Corporation (KRMC) was performed to examine the contribution of each radiation source affecting dose rate distribution around the cask. Various radiation sources, which contain neutron and gamma-ray sources placed in active fuel region and the activation source, and imaginary nuclear fuel were all considered in the MCNP calculation model to realistically simulate the actual situations. It was found that the maximum external and surface dose rates of the spent fuel cask were satisfied with the domestic standards both in normal and accident conditions. In normal condition, the radiation dose rate distribution around the cask was mainly influenced by activation source ($^{60}Co$ radioisotope); in another case, the neutron emitted in active fuel region contributed about 90% to external dose rate at 1m distance from side surface of the cask. Besides, the contribution level of activation source was dramatically increased to the dose rates in top and bottom regions of the cask. From this study, it was recognized that the detailed investigation on the radiation sources should be performed conservatively and accurately in the process of radiation shielding analysis for a BUC cask.