• Wind and Structures
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• 제22권3호
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• pp.349-368
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• 2016

A preconditioning technique is presented for a simultaneous solution to wind-membrane interaction. In the simultaneous equations, a linear elastic model was employed to deal with the fluid-structure data transfer at the interface. A Lagrange multiplier was introduced to impose the specified boundary conditions at the interface and strongly coupled simultaneous equations are derived after space and time discretization. An initial linear elastic model preconditioner and modified one were derived by treating the linearized elastic model equation as a saddle point problem, respectively. Accordingly, initial and modified fluid-structure interaction (FSI) preconditioner for the simultaneous equations were derived based on the initial and modified linear elastic model preconditioners, respectively. Wind-membrane interaction analysis by the proposed preconditioners, for two and three dimensional membranous structures respectively, was performed. Comparison was made between the performance of initial and modified preconditioners by comparing parameters such as iteration numbers, relative residuals and convergence in FSI computation. The results show that the proposed preconditioning technique greatly improves calculation accuracy and efficiency. The priority of the modified FSI preconditioner is verified. The proposed preconditioning technique provides an efficient solution procedure and paves the way for practical application of simultaneous solution for wind-structure interaction computation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.852-857
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• 1990

The purpose of this paper is to design a robust controller for a class of time-varying systems with bounded disturbance described by the differential equation. The robust desiging method proposed in this paper, called "incentive design method" is different from developed designing methods in the past, and has following properties. The robust control law designed by this method can guarantee a certain value of the cost functional no matter how the disturbance vary within the given bounds. Here, the certain value of the cost functional may not be a saddle-point value, but is the value selected by a system designer. Therefore, the bounded disturbance has at least no bad effect on the value of the cost functional during finite interval of time. The method is based on the theory of incentive differential games. In addition, the form of control law is constructed by the system designer ahead of time. A numerical illustrative example is given in this paper. It is shown from this derivation and this numerical example that the approach developed in this paper is effective and feasible for some practical control problem.l problem.

• 지역연구
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• 제14권2호
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• pp.65-75
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• 1998

Education is widely recognized one of main sources for growth. This paper attempts to incorporate the general recognition into formal regional growth model. The model structure is largely neoclassical. It produces a single good with the two factors, educated labor and non-educated labor, via a constant return production migrating to the region with the higher real wage. The educated labor in a region is accumulated by two sources, migration and physical education capital, while the non-educated labor is by only migration. The paper shows that regional growth equilibrium is characterized as a saddle point. This indicates the presence of the minimum threshold size that must be overcome before a region may grow. It contrasts sharply with results obtained in regional growth models. The paper suggests that regional growth is determined less by the technical characteristics of regional production function characteristics of regional production function but by the stock combination of educated function but by the stock combination of education labor and non-educated labor. Based on this result, the impact of agglomeration economies on regional growth is explored. It is by phase diagram demonstrated that the presence of agglomeration economies do not always lead a region to growth since there still exists the minimum threshold even in the presence of agglomeration economies.

• 대한조선학회논문집
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• 제46권6호
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• pp.675-687
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• 2009

In general, the forming process of the curved hull plates consists of sub tasks, such as roll bending, line heating, and triangle heating. In order to complement the automated curved hull forming system, it is necessary to develop an algorithm to classify the curved hull plates of a ship into standard shapes with respect to the techniques of forming task, such as the roll bending, the line heating, and the triangle heating. In this paper, the curved hull plates are classified by four standard shapes and the combination of them, or saddle, convex, flat, cylindrical shape, and the combination of them, that are related to the forming tasks necessary to form the shapes. In preprocessing, the Gaussian curvature and the mean curvature at the mid-point of a mesh of modeling surface by Coon's patch are calculated. Then the nearest neighbor method to classify the input plate type is applied. Tests to verify the developed algorithm with sample plates of a real ship data have been performed.

• 대한소아치과학회지
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• 제5권1호
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• pp.64-75
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• 1978

In order to know cephalometric norms for the preschool children, this roentgeno cephalometric study was undertaken in each 50 Korean male and female children of primary dentition age from 4 to 5 year. The following results were obtained. 1. In the skeletal analysis, there was no significant difference between male and female in angular measurement and the linear measument of the male was generally greater than that of the female. 2. Saddle angle was $122.3^{\circ}$, articular angle was $147.6^{\circ}$, gonial angle was $119.4^{\circ}$ and the sum of each angle was $396.1^{\circ}$ in male and $396.6^{\circ}$ in female. 3. The ratio of mandibular body to anterior cranial base was about 1 : 0.91. 4. In the primary dentition, suggested that the nasion and point A move forward relative to sella turcica in a fashion, pogonion and point B are equal in angular position relative to plan S-N, bony chin and chin button was yet underdeveloped, and the forward growth of mandible was seen rapid than maxilla after 4 years. 5. Suggested that the percentage of anterior facial height to the posterior facial height were 64.4% in male and 64.1% in female. 6. Maxillary primary incisors was more upright than the permanent incisors, mandibular primary incisors was inclined lingually relative to the permanent incisor, and primary incisors was more upright than the permanent incisors. 7. Maxillary primary incisors in female was inclined labially than male. 8. In the the relationship of the upper lip and lower lip to the esthetic line, the upper lip was 2.11mm and the lower lip was 2.33mm front of the esthetic line.

• 한국구조물진단유지관리공학회 논문집
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• 제14권3호
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• pp.186-195
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• 2010

본 논문은 SC합성보에 정착구의 높이, 새들의 형태, 가력시점을 변수로 하여 비부착 포스트텐션 보강을 하고 휨실험을 통해 보강방법을 평가하여 적절한 보강방법을 제시하고자 하엿다. 실험결과 보강 전 SC합성보의 최대내력은 실험값/이론값이 0.97로 나타났으나 보강 후는 1.00~1.21로 나타나 보강효과를 확인할 수 있었다. 변위 및 변형률 분석결과 정착구의 높이 및 가력시점에 상관없이 보강 후 중립축에 정착구를 설치한 D120계열 실험체가 최대하중이후 급격한 하중저하 없이 변위가 지속적으로 증가하며 각 부분의 변형률도 비교적 적게 나타나는 안정적인 거동을 했다. 보강효과면에서 선 가력 후 보강한 SCR-UD120실험체가 보강 전 SC합성보에 비해 최대내력이 1.72배 증가하여 가장 우수한 것으로 나타났다.

• 한국터널지하공간학회 논문집
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• 제19권4호
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• pp.669-683
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• 2017

본 연구의 목적은 지하 콘크리트 구조물에서 부분적으로 발생하는 누수를 처리하기 위하여 기존에 제안된 전단면 유도배수시스템을 수정하여 제안하는 것이다. 누수된 부분에만 유도배수시스템을 적용하기 위하여 누수된 지하수를 유도배수시스템내에서 집수 지점으로 유도하는 기술과 집수된 지하수를 지하 콘크리트 구조물의 배수 시설로 이동시키기 위한 기술을 추가 제안하였다. 유도배수시스템내로 누수된 지하수를 집수 지점으로 유도하기 위한 4가지 방수 재료들, 즉, 다공질의 고무 재료인 Durkflex, 초강력 접착력을 가진 KE-45 실리콘 접착제, 폴리머 계열 재료인 Hotty-gel 및 일반 실리콘 접착제에 대한 성능 평가를 수행하였다. 방수 재료 Hotty-gel만 완벽한 방수 성능을 보였고 나머지 3가지 방수 재료들에서는 누수가 발생하였다. 선정된 방수 재료 Hotty-gel과 집수 지점에서 배수시설로 누수된 지하수를 이동시키기 위한 배수관 및 고정 새들(saddle)을 추가한 유도배수시스템을 콘크리트 옹벽에서 시험 시공하였다. 재령 7일, 14일, 21일, 28일, 2개월, 및 3개월에 수정된 유도배수시스템 배면에 1,000 ml의 물을 주입하여 방수 성능과 유도배수 성능을 평가하였다. 재령 3개월까지 방수 성능 및 유도배수 성능에는 전혀 이상이 없는 것으로 확인되었다. 수정된 유도배수시스템의 총 공사 기간 및 공사비에 대한 평가를 위하여 표면 정리 단계, 누수 처리 단계 및 단면 복구 단계별로 기존 누수 보수 공법과 비교하였다. 작업 내용, 보수 재료, 시공 장비, 작업 시간, 작업 인원 등을 고려한 개략적인 총 공사 시간 및 공사비에 대하여 비교하였다. 각 시공 단계별로 비교 분석한 결과 수정된 유도배수시스템은 기존의 누수 처리 공법보다 총 공사 기간 및 공사비를 절감할 수 있을 것으로 판단되었다.

• 한국산학기술학회논문지
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• 제9권5호
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• pp.1349-1353
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• 2008

충청남도, 천안시 대기 에어로졸의 입경별 농도 및 이온성분 특성을 분석하고자, 2006년 3월부터 2007년 4월까지 천안시 상명대학교에서 Cascade Impactor를 장착한 High Volume Air Sampler를 이용하여 대기 시료를 채취 분석하였다. 입경별 에어로졸의 일평균농도는 TSP, PM10, PM2.5, PM1이 각각 61.7, 55.2, 43.7, $33.2{\mu}g/m^3$였으며, 직경이 $1{\sim}3{\mu}m$인 영역을 경계로 조대영역과 미세영역으로 나누어지는 전형적인 도심지 특성을 나타냈다. 이 중 미세영역입자인 PM2.5이 전체 에어로졸의 70.8%를 차지하였다. 이들 에어로졸 입자의 성분 분석 결과 양이온은 ${NH_{4}}^+$, $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$이, 음이온은 ${SO_{4}}^{2-}$, ${NO_{3}}^-$, $Cl^-$가 주요 성분이었으며, 이들 수용성 이온이 차지하는 비율은 조대입자에서 37.4%, 미세입자에서 46.2%였다.

• 한국식품저장유통학회지
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• 제17권1호
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• pp.84-90
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• 2010

본 연구에서는 국내산 사과의 주스 가공과정에서 patulin 함량 최소 방법을 모니터링 하였다. 중심합성계획법으로 ascorbic acid 첨가량(100, 200, 300 및 400 ppm)과 활성탄 사용량(50, 100, 150 및 200 ppm)을 독립변수로 설정하고 각각의 조건에서 사과주스를 제조한 결과 patulin 잔류량은 ascorbic acid 함량 237.77 ppm, 활성탄 함량 106.58 ppm에서 최소점을 나타내었다가 점차 증가하는 경향을 나타내었다. 당도는 활성탄 사용량보다는 ascorbic acid 첨가량에 영향을 더 많이 받는 것으로 나타났으며, 총 페놀성 물질 함량의 정상점은 안장점으로 나타났다. 또한, 총 플라보노이드 함량의 예측된 정상점은 최대점으로 나타나 ascorbic acid와 활성탄 함량이 증가할수록 높은 함량을 나타내었다. 이상의 결과 사과주스 가공시 patulin 잔류량은 ascorbic acid 246~274 ppm (v/v), 활성탄 93~122 ppm (v/v)에서 최소화 되는 것으로 나타났으며 사과주스 가공 품질인자의 $R^2$는 모든 구간에서 1~10% 수준에서 유의성이 인정되었다.

• 한국식품조리과학회지
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• 제21권4호
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• pp.514-527
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• 2005

The purposes of this study were firstly to optimize the recipe for iced cookies by cooking with five different ingredient levels of $Jinuni\;bean(X_1),\;butter(X_2)\;&\;sugar(X_3)$ and secondly to analyze the chemical and sensory test results by using RSM(Response Surface Methodology). As a result of this test, water activity decreased with increasing contents of butter or sugar, while hydrophilic browning decreased independently with increasing sugar content. There was a positive correlation(p<.001) between specific gravity and hardness, although the result was not uniform due to the interaction of each factor. There was a negative correlation(p<.001) between the spread ratio and gravity or hardness, and it tended to increase with increasing each content. Color value L and color value a had positive correlation (p<.001) and the value tended to decrease with increasing the quantity of Jinuni bean. Generally, the strength of the cookies showed a saddle point at the peak of the 3d graph. As a result of sensory evaluation, the color was sensitive to the contents of sugar and Jinuni bean, the texture was sensitive to the contents of butter and sugar, and the taste and overall quality were sensitive to all three factors. Color had a positive correlation(p<.05) with the taste, texture and overall quality. There were high positive correlations(p<.001) between the taste, texture and overall quality. The preference data showed an up-swollen, parabolic shape in the center of the 34 graph, which enabled the optimum value to be determined and the optimum mixture ratio which fulfilled all sensory items was Jinuni bean 93g, butter 188.5g and sugar 155g, indicating a substitution of flour by $44\%$.