• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.2
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• pp.132-140
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• 2008

본 논문은 시간 제약을 갖는 차량 라우팅 문제를 해결하기 위해 유전자 알고리듬과 부분 최적화 알고리듬을 적용한 방법을 소개한다. 유전자 알고리듬에서의 염색체는 노드를 나타내는 정수의 순열로 표현되어 직접적인 해를 나타내지 않지만, 경험적 방법에 의한 해석을 통해 유효한 해로 변형되도록 하였다. 유전자 알고리듬에 의해 생성된 주어진 수의 우수한 해들에는 세 부분 최적화 방법이 순차적으로 적용되어 보다 좋은 해를 생성하도록 하였다. 부분 최적화 방법들에 의한 해는 다시 유전자 알고리듬의 해로 바뀌지 않도록 하여 두 알고리듬은 느슨하게 연결되도록 하였다. 솔로몬의 데이터를 이용한 실험에서 본 연구에서의 방법이 모든 문제에 대해 우수한 해를 생성함을 나타내었다. 특히, 지금까지 알려진 가장 우수한 경험적 방법에 비교될 만한 결과를 가져옴을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1020-1023
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• 2008

멀티스레드 프로그램의 효과적인 디버깅을 위해서는 스레드의 비결정성에 의해 야기되는 다양한 수행 양상의 직관적인 이해가 중요하다. 스레드 수행 양상을 시각화하는 기존의 기법들은 공유 변수의 접근사건들 간의 부분 순서를 표현함으로써 시각적 복잡도가 높거나 이전 수행에서 결정된 락킹 순서를 표현하여 잠재되어 있는 다른 수행 양상에 대한 정보를 제공하지 못 한다. 본 논문은 프로그램 수행의 비결정적인 부분 순서는 락의 종류와 속성을 포함하는 코드 블록으로 시각화하고, 결정적인 부분 순서는 블록들을 연결하는 간선으로 시각화한다. 본 연구의 그래프는 플랫폼에 독립적인 Java Swing으로 구현하고 합성 프로그램을 사용하여 효과성을 실험한다.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.103-109
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• 2016

Polyethylene pipes has useful benefits which are anti-corrosive and flexible material, so it is used to gas pipes but also class 3 water pipes of nuclear power plant, process pipes of petrochemical plant and chemical plant. So the usage of polyethylene pipes is widely increased. But it has been limited for the usage of polyethylene, because it can not be directly detected to fusion joints by using non destructive evaluation. Polyethylene pipes are connected by two methods, one is butt fusion and the other is electrofusion. Butt fusion is widely used to connecting the pipes. It is proposed to method for determining the reliability of joints in this study that is detection of the melt flow zone at fusion joints. In this study, middle density polyethylene is used, outside diameter of the test specimen is 225mm and thickness is 20.5mm. Speed of ultrasonic of this test specimen is 2,200m/s. Test specimens were fabricated by varying the heating time which means from 0% to 130% applying time through heating plate to polyethylene for detecting melt flow zone. Also 4 additional test specimens were made, one was made that not scrapping attached surface of pipes but applying 100% of the proper heating time and the others were made to include of soil, gravel and vinly tape paper at fusion joints, that were also applied 100% of proper heating time. Ultrasonic testing to measure the melt flow zone of 20 test specimens was conducted by using 3.5MHz and 5.0MHz ultrasonic probes and melt flow zone measuring was conducted to three times at different point to one specimen. To differentiate the melt flow zone signal, post image processing was equally conducted to all test results and image levels, contrast, sharpen, threshold were adopted to all teat results and the test results were displayed gray scale. From the results, for the shorter heating times the reflection area of multiple echo have been increased, so the data was obtained from the position where it can be eliminated as much as possible. At 80% of proper heating time(168 sec.), the signal of melt flow zone was obtained clearly, so measuring could be conducted. From 7% of proper heating time(15 sec.) to shorter heating times. we could not obtain the signal because test specimen was not fused. From the result, we can verify that measuring of melt flow zone by using phased array ultrasonic imaging method is possible. And we can verify to complete and incomplete butt fusion by measuring the melt flow zone.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.515-524
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• 1999

A methodology to resolve a TOPMODEL problem has been suggested, which is associated with the spatial distribution of soil moisture behaviour in a runoff mechanism. A procedure to integrate the spatial information of saturation deficit in the TOPMODEL reflects the connectivity of saturated area in a watershed. The developed algorithm includes an improved basis in tracing the runoff path without increasing the number of parameters. The performance of the developed algorithm has been tested to an upland subwatershed, namely Dongok, which is the IHP watershed located at Wichon, Korea. Comparing with the original statistical version of the TOPMODEL, it has been found that the suggested algorithm can relax an overestimation of peak rate in the runoff simulation.

• Journal of Labour Economics
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• v.34 no.3
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• pp.119-139
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• 2011

Using a establishment-worker matched data, this paper estimates wage differentials between standard and non-standard workers. Unlike previous studies, we estimate a fixed-effect model for the tree-way error-components that control for both unobserved individual heterogeneities and unobserved firm heterogeneities. The estimation results show that standard workers earn 6.5~8.4% mire than non-standard workers. This wage premium is 30~40% of the wage differential estimated from the OLS model. The results implies that a large proportion of the wage differentials between standard and non standard workers can be explained by unobserved firm and individual characteristics.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.29-40
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• 1999

This study presents a simplifled calculation method for required ductility of coupling beams in precast coupled shear walls at preliminary seismic design stages. Deflection of precast coupled shear walls based on a continuum approach is combined with inelastic gap opening of horizontal connection of panels to provide a relationship between the system-level ductility and the element-level ductility in a precast coupled shear wall. The equation proposed herein for ductility requirement for coupling beams shows that higher stiffness and lower strength of coupling beams result in high ductility reuqirement. The equation also shows that the ductility requirement is proportional to the degree of gap opening of the story in question. However, the coupling beam ductility in higher stories are not affected by gap openings of horizontal connections of panel.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.309-318
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• 2013

Abutment-to-pile connection in an integral abutment bridge is vulnerable to lateral displacement induced by thermal movement of the superstructure. However, previous researches have merely focused on the connection. In order to improve the performance of the connection, new abutment-to-pile connection designs were proposed based on quasi-static nonlinear finite element model. The reinforcement detail specified in PennDOT DM4 and HSS tube were barely effective in controlling crack growing but spiral rebar effectively performed to delay crack growth as well as absorbing energy capacity. However, it was found that delaying cracking and strengthening the connection also caused the high lateral load in superstructures. Consequently, shape of HP pile were modified to introduce plastic hinge of the HP pile for reducing the lateral load in superstructures. Connections with modified HP pile significantly prevented crack propagations under the lateral displacement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.427-431
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• 2007

The safety and the durability of the arm as an automotive chassis part under the fatigue can be predicted in this study. The fatigue life is sharply decreased from 0.5 to 0.75 at the change of load which is the amplitude load divided by average load. But its life is slightly decreased at the change of load from 0.75 to 1.5. The influence of fatigue life according to the change of load can be predicted by these results. As the value of maximum damage is 2.2 and the value of maximum compressive strain or stress is $-6.93{\times}10^{-3}$ or 349 Mpa at the connected part of rod end applied by concentrated load respectively, there is the greatest possibility of destruction due to the compression at this part.

• 한국HCI학회:학술대회논문집
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• 2007.02c
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• pp.194-198
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• 2007

본 연구의 주제는 텍스트를 어떻게 회화적이미지로 전환시킬 수 있을까?에 대한 것이다. 오늘날 디지털 환경 속에 있는 우리는 이미지 중심의 세계 속에 살고 있다. 과거 텍스트가 해왔던 정보의 생산과 전달 그리고 저장의 역할을 오늘날은 상당부분 이미지가 하게 되었다. 하지만 그럼에도 불구하고 아날로그 방식과 정서는 여전히 우리 곁에 남아있는 것도 사실이다. "Yesterday to Today"는 문자의 최소 단위인 알파벳을 통하여 이미지를 재현하려는 작품이다. 이 작품은 크게 두 가지 Idea로 이루어지는데 하나는 복수개의 실시간 영상 소스를 이용하여 이미지를 구성해내는 것과, 다른 하나는 텍스트에 의한 이미지의 변환이다. 복수개의 실시간 영상 소스는 프로그램이 작동하는 컴퓨터와 직/간접적으로 연결되어 전달되는데, 직접적으로 연결되어 근거리의 특정한 지점으로부터 영상 소스를 받을 수 있고, 또 하나의 방법은 인터넷을 통한하나 이상의 원거리 지점으로부터 보내어지는 영상을 조합하여 받을 수 있다. 프로그램 구현 개념은 픽셀 소스 카메라에서 캡쳐된 최초 이미지를 명도, 색상, 채도로 분류하고, 이것의 각각을 26개의 구간-자판의 개수에 의하여 정해짐-으로 나누고, 다시 그 각각의 구간을 26단계로 나눈다. 이렇게 나누어진 구간들은 알파벳과 1:1로 대응시켜 결과이미지의 해당 부분을 수치대로 재현하도록 프로그램 시킨다. 이미지의 부분들을 지정하기 위하여 특정한 텍스트로부터 알파벳의 빈도수를 조사했는데, 이 조사를 바탕으로 빈도수의 많고 적음에 따라 이미지부분들이 26개 구간으로 정해졌다. 이미지 재현 방법은 사용자가 모니터 위의 Result Image Cam을 통하여 얻고자 하는 이미지를 캡쳐한 후, 특정한 텍스트를 타이핑하면 이미지를 재현할 수 있는데, -입력된 텍스트의 알파벳은 프로그램이 지정한 HSI 컬러 모델의 영역과 1:1로 대응하게 하였다-이 이미지는 특정 장소에 실시간으로 받아진 영상을 데이터화 한 소스에 의하여 만들어진다. 이미지를 재현할 때 텍스트에 따라 알파벳 빈도수는 달라질 수 있으므로 비록 최초 이미지가 동일할지라도 얻고자하는 결과 이미지가 달라진다. 그러므로 사용자는다양한 창조적 경험을 할 수 있다.

• Journal of the Korea Institute of Building Construction
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• v.20 no.5
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• pp.449-457
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• 2020

Due to the improvement of living standards and avoidance of the 3D industry, it is difficult to find young and competent domestic workers at construction sites, and most foreign workers are contributing to the replacement, but the quality is still deteriorating due to lack of skilled workers and aging. Precast method is a method that make members in factory and assembles them on site, which can be expected to improve labor force and quality. This study is intended to provide basic data for the development of hang-type PC beams that can be applied to the determination of the field application of developed PC beams. The U-type connecting material is installed on both ends of the hang-up PC beam, and the role of the U-type connecting material is very important because it is a simple construction method through the U-type connecting material. In addition, the performance of the U-type connecting material will determine the performance of the hang-type PC beam as the final destruction occurs in the hang-type PC beam. The material properties of U-type connecting material were identified through structural experiments, and the end test corresponding to the partial experiment was conducted based on the material test results identified. Finally, the final design value of PC beams was proposed through structural experiments for application to the site.