• Journal of KIISE
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• v.42 no.2
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• pp.227-234
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• 2015

This paper proposes a modified MI-SVM algorithm by considering data distribution. The previous MI-SVM algorithm seeks the margin by considering the "most positive" instance in a positive bag. Positive instances included in positive bags are located in a similar area in a feature space. In order to reflect this characteristic of positive instances, the proposed method selects the "most positive" instance by calculating the distance between each instance in the bag and a pivot point that is the intersection point of all positive instances. This paper suggests two ways to select the "most positive" pivot point in the training data. First, the algorithm seeks the "most positive" pivot point along the current predicted parameter, and then selects the nearest instance in the bag as a representative from the pivot point. Second, the algorithm finds the "most positive" pivot point by using a Diverse Density framework. Our experiments on 12 benchmark multi-instance data sets show that the proposed method results in higher performance than the previous MI-SVM algorithm.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.22-23
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• 2002

Titanium은 높은 강도, 낮은 밀도, 부식에 대한 저항 등, 타 금속에 비해 월등히 뛰어난 성질을 가지고 있기 때문에 산업 전반에 거쳐 그 응용이 크게 증가하고 있으며, 특히 고온에서의 응용이 중요성을 띠게 됨에 따라 고온으로의 상전이 관계에 따른 구조적 규명이 필요하다. 순수한 titanium은 상온에서 조밀충진 육방정계의 α-상구조(a=2.953Å, c=4.683 Å, P6₃/mmc)를 이루고 있으나, 대략 880℃ 이상에서는 β-상의 체심입방정계 (a=3.320Å, Im3m)로 상전이가 되는 것으로 알려져 있다. 이에 대한 대부분의 연구가 kinetics와 thermodynamics에 관련되어 있으며, TEM을 이용한 직접가열실험은 거의 전무한 상태이다. 본 실험에서는 TEM 직접가열을 통하여 titanium의 고온에서의 상전이와 가열시 발생할 수 있는 산화층 형성을 연구하였다. TEM 시편은 순도 99.94％의 titanium foil(Alfa Aesar, ＃00360, 0.025mm thick)를 이용하였고, 분석 장비로는 에너지여과 기능이 있는 TEM(EM912 Omega, Carl Zeiss)과 Gatan사의 double-tilt heating holder를 사용하였다. Titanium의 상전이를 관찰하기 위해 900℃ 까지 분당 10℃ 의 속도로 가열을 하였다. 통계적 분석 오차를 줄이기 위해 서로 다른 4군데의 관찰영역을 선택하여, 상온 - 600℃ - 900℃ - 상온의 단계별로 회절패턴을 관찰 및 기록하였고, 발생 가능한 산화에 대해서는 동일한 장비를 사용하여 EDS 분석을 하였다. 상온에서의 서로 다른 영역의 회절패턴들은 결함의 존재에 상관없이, 온도가 증가함에 따라 그 결함수가 증가하게 된다. 특히 600℃ 에서는 쌍정과 관련된 회절점들이 본래의 회절점 주위에 형성되어있지만, 각 면들의 격자상수의 변화는 나타나지 않았다. 그러나 900℃ 에서는 쌍정에 의한 회절점의 수가 증가하며, 회절점 사이에 발달한 뚜렷한 막대모양의 강도분포와 격자상수의 변화를 관찰할 수 있었다. 다시 상온으로 냉각시킨 후 관찰한 각각의 회절패턴에서는 격자 상수의 감소와 함께 900℃에 보여진 막대 모양의 강도분포와 쌍정에 의한 회절점들이 여전히 남아있었다. EDS분석 결과 가열 실험을 통해 시편이 열적 산화가 되어 있음을 확인 할 수 있었다. 순수한 titanium의 α-상에서 β-상으로의 상전이를 파악할 수 있는 격자상수의 변화자체는 매우 작은 값이기 때문에 상온과 900℃ 에서 기록된 전자회절패턴 상에서의 면간거리와 면간각도의 측정만으로는 상전이 여부를 명확히 구별할 수 없었다. 그러나, 결함에 의한 상변화가 900℃ 에서 심하게 관찰되어지는 것은 상전이와 관계가 있는 것으로 볼 수 있다. 고온에서 상온으로의 가역적 반응을 관찰할 수 없었던 이유는 열적산화로 생긴 산화층의 산소원자들이 고온의 상전이 과정 중에 Ti 원자와 반응이 일어나 TiO/sub X/ 구조로 전이되었기 때문으로 추정하고 있다.

• Fire Science and Engineering
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• v.24 no.4
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• pp.98-103
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• 2010

The design disaster prevention of first consideration is security for the people in the buildings. However, it is difficult to make a project for considering variable cases, declined visibility of smoke, distance from another person, mentality, knowledge of clearway etc. This study purpose is, analysis variable cases and modularization of pattern movement to practice basic information for evacuation of simulation which is used RTLS (Real Time Location System) system. It is useful to sense the electric waves from the Tag and grasp the real-time position. The pattern movement of evacuation were analyzed prescription eyeglasses which is used RTLS system to consider following 3 actions; analysis of relations that declined visibility effect the decline of movement velocity, analysis rate of flow with the size of door to estimate the optimum size of door in building and analysis the pattern movement that a bottleneck situation with abundant of people passed together to these exit. The confirmed of propriety of the interpretation about the actual people to evacuate is expected applying the numerical formula in various situation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.637-645
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• 2017

Jeju Island is composed of irregular volcanic rock layers formed by several volcanic activities. Since structure such as the offshore wind turbine has to support considerably large over turning moment due to long distance from foundation to load point and relatively large horizontal load. Pile foundations are needed to economically support such structure even in the case of rock layer. Therefore, in this study, mechanical performances are estimated by mixing ratio of water, cement, and sand to figure out optimal mixing ration of filling material for pile penetrated to rocky layers, and outcomes of this study are compared and analyzed with results of other researches. In the same conditions, mechanical performances of the mortar (S/(S+C)=20~40%) are better than those of cement paste and soil cement. On the basis of major outcome of this study, appropriate range of mixing and a strengthening model are suggested.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.171-179
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• 2002

The three-dimensional long-range dispersion model has been developed to understand the characteristics of the transport and diffusion of radioactive materials released into atmosphere. The model is designed to compute air concentration and ground deposition at distances up to some thousands of kilometers from the source point in horizontal direction. The vertical turbulent motion is considered separately within the mixing layer and above the mixing layer. The test simulation was performed In the area of Northeast Asia. The release point was assumed in the east part of China. The calculated concentration distributions art mainly advected toward the southeast part of release point by the wind fields. The developed model will be used to estimate the radiological consequences against a nuclear accident. The model will be supplemented by the comparative study using the data of the long-range field experiments.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.584-589
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• 1998

The study was carried out to investigate heavy metals of rainfall and soil at industrial, urban and rural area, and to estimate the relationship between rainfall and soil. Heavy metals of stemflow, throughfall and rainfall in Pinus thunbergii and Quercus spp were ordered Zn>Cu>Pb>Cd in industrial area, and Zn>Pb>Cu>Cd in urban area. All heavy metals were detected high in industrial areas, and especially those of industrial area were high in stemflow. Heavy metals in soil by distance from stem were highest in 20cm distance from stem. Soil heavy metals in survey sites were the same order as those of rainfall. The correlation of heavy metals between rainfall and soil were positive, the regression obtained was as follows ; Zn was Y=7.79+4.78X($r=0.8685^{**}$), Pb was Y=7.90+4.53X($r=0.7242^*$) and Cu was Y=3.89+3.91X($r=0.8658^{**}$).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.4
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• pp.139-146
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• 1987

The 3-dimensional deformation measurement by the terrestrial photogrammetry is consist of 3-dimensional coordinates computation, displaced point detection and deformation estimation of object targets. In this study, at the first step of deformation analysis, the variation of the variance-covariance matrix for the exterior orientation elements was analyzed by the increment of the ground control points and the photos in the Bundle adjustment. And then, to give the constraints for improving accuracy of ground control points, the concept of Free-Network adjustment was applied to Bundle adjustment. As a result, we knew that it was desired in the accuracy and the economy, the observation time when the numbers of ground control point and photo were respectively 6 points and 3 photos. In addition, in the case of applying the concept of Free Network adjustment in Bundle adjutment, it was desirable that the space distance for the constraints is distributed outside.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.16-23
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• 2006

This paper presents the development of the fast Direction Finder using direct conversion method, which can intercept for short pulse signal of less' than 1 msec. in RF Down Converter, and CVDF(Correlative Vector Direction Finding) algorithm, which estimates DoA (Direction of Arrival). The configuration and characteristics of direction finder using 5-channel equi-spaced circular array antenna are presented and the direct conversion techniques for removing tuning time using I/Q demodulator are described. The CRLB of our model is derived, the principles of 2 kind of CVDF algorithm are explained and their characteristics are compared with CRLB w.r.t the number of samples and spacing ratio. The RF Down Converter prototype using direct conversion method is manufactured, the 2 kind of CVDF algorithm are applied and their performance are analyzed. Finally it is confirmed the LSE based CVDF algorithm is better than correlation-coefficient based except for ambiguity protection capabilities.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.133-141
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• 2008

As interactive multimedia have come into wide use, user interfaces such as remote controllers or classical computer mice have several limitations that cause inconvenience. We propose a vision-based pointing device to resolve this problem. We analyzed the moving image from the camera which is embedded in the pointing device and estimate the movement of the device. The pose of the cursor can be determined from this result. To process in the real time, we used the low resolution of $288{\times}208$ pixel camera and comer points of the screen were tracked using local optical flow method. The distance from screen and device was calculated from the size of screen in the image. The proposed device has simple configurations, low cost, easy use, and intuitive handhold operation like traditional mice. Moreover it shows reliable performance even in the dark condition.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.436-446
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• 2015

It is suggested investigating method about the existing state of demand in this study. The total demand of 357 water amenity zones in 2014 is estimated based on the growth curve models. The effects of population density and distances between water amenity zones and metropolises populated over 1 million are investigated on each river system. The suitability like RMSE and MAPE of logistic and gompertz models are considered to select more suitable model for each water amenity zone. Demand for water amenity zones in 2014 is seemed to be rather high at Han Gang river system and Chungcheongbukdo after analyzing. The influence of population density is rarely effective except Geum Gang river system. The influence of metropolis on the demand for water amenity zones is higher at Geum Gang river system than others.