• Journal of The Korean Association For Science Education
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• v.17 no.2
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• pp.163-178
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• 1997

The purpose of this study is to investigate the effect of categorizing activities in lessons on improving critical thinking to meet energy environment issues in every day situation, supposing that there are not only scientific concepts but also critical thinking ability in scientific literacy to meet social controversies related with science intelligently. Categorizing Activity Program was developed and applied to the 10th grades(n=51) in Seoul for about one month. The program was consisted of two domains. They studied science concepts of various aspects of science, technology and society related with energy and environment in the first and second domain repectively, in the while, two critical tasks which include articles from newspapers and magazines were assigned to them for the development and evaluation of critical thinking abilities. The scores of critical thinking ability, the cognitive element, and critical thinking inclination, the affective element, were increased meaningfully(p<.05). In conclusion, categorizing activity as a strategy of concept attainment was effective in improving critical thinking for seeing various aspects with various view points needed in controversial issues related with energy and environment.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.9
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• pp.1039-1048
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• 2015

In this paper, we propose an efficient stair locomotion method for a quadruped robot with mechanism of insectile legs using genetic algorithm(GA). In the proposed method, we first define the factors and the reachable region for the stair locomotion. In addition, we set the gene and the fitness function for GA and generate the gait trajectory by searching the landing position of a quadruped robot, which has the minimun distance of movement and the optimal energy stability margin(ESM). Finally, we verify the effectiveness and superiority of the proposed stair locomotion method through the computer simulations.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.12
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• pp.1857-1864
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• 2013

In 21 century, it is difficult to define the limit of home automation, Recently, based on the advanced digital communication technology and necessity, The scope of the home automation has widened to home energy management, integrated reading of home and home health care etc. beyond the existing home automation. However, those methodologies reduce the efficiency and economy, and make it harder to realize a compact home automation because those methodologies are proposed independently without a unified standard. Therefore, this paper investigates and analyzes these methodologies, and then proposes an advanced home automation system that enables a compact design and improves the efficiency and economics of the home automation system based on the analyzed result.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.330-342
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• 1998

The effect of rubber mold on densification behavior of pure iron powder was investigated under cold isostatic pressing. The thickness effect of rubber mold was also studied. The elastoplastic constitutive equation based on the yield function of Shima and Oyane was implemented into the finite element program(ABAQUS) to predict compaction responses of metal powder under cold isostatic pressing. The hyperelastic constitutive equation based on Moony-Rivlin and Ogden strain energy potentials was also employed to analyze deformation of rubber mold. The coefficients of the strain energy potentials were obtained from tension and volumetric compression data of rubber. Finite element results were compared with experimental data for densification of pure iron powder under cold isostatic pressing.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.54-54
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• 2003

목적 : 방사선치료는 복잡하고 다양한 장비를 이용하여 고에너지 고선량의 방사선을 다루기 때문에 세심한 정도관리를 바탕으로 기술적 관점에서의 적절한 방사선치료장비 사용과 실제 환자치료시의 절차들에 대한 완벽한 지침서가 마련되어야 할 필요가 있다. 본 연구의 목적은 의료용 선형가속기에 연관된 방사선사고와 잠재적 사고유형들을 분석하여 환자와 종사자의 안전을 보장하고 사고를 예방키 위한 안전관리 기준을 개발하고자 하였다. 대상 및 방법 : 본 연구에서는 국내 13 개 방사선치료기관에 대한 안전관리 실태를 자체 개발한 100 여 문항의 설문으로 조사, 분석하였다. 또한, 국제적으로 사용하고 있는 안전관리기준들과 보고된 방사선 사고사례 들을 조사하였고, 방사선치료 전 과정을 통해 잠재적 사고유형을 추정함으로서 방사선치료의 안전관리를 위 해 필요한 요구사항들을 도출하고 이를 바탕으로 의료용 선형가속기에 관련된 안전관리 기준을 마련하였다. 결과 : 본 연구에서는 방사선치료 시 환자와 종사자의 안전을 보장하고 사고방지를 위하여 단계별 안전관리 기준을 개발하였으며, 방사선 치료과정에서 일어날 수 있는 다양한 실수나 사고들을 일목요연하게 관리 할 수 있는 흐름도를 구축하였다. 결론 : 본 연구 결과는 방사선치료에 사용되는 선형가속기에 대한 방사선의 안전과 품질보증을 개선하게 될 것으로 생각된다. 또한, 잠재적 방사선 사고의 예방뿐 아니라 국내의 방사선치료 안전관리 기준 마련에 기초자료로 활용될 수 있을 것이다.

• Korean Journal of Materials Research
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• v.17 no.12
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• pp.660-663
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• 2007

Piezoelectric energy harvesting from our surrounding vibration has been studied for driving the wireless sensor node. To change the vibration energy into the electric-energy efficiently, the natural frequency of cantilever needs to be adjusted to that of a vibration source. When adding 6.80g mass on the end of the fabricated cantilever, a natural frequency shifts from 136 Hz into 49.5 Hz. In addition, electro-mechanical coupling factor increased from 10.20% to 11.90% and resulted in the 1.18 times increase of maximum output power.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.4
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• pp.388-394
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• 1994

A Hg(0.79)Cd(0.21)Te single crystal has been grown by the Traveling Heater Method(THM). Its zinc blend cubic structure is identified from the X-ray diffraction patterns and its lattice constant is determined to be $6.464 {\AA}$ using the least-square method of Cohen. From the values of the lattice constant, the composition x is determined to be 0.21. The electron density is calculated from the relative intensities of the scattered X-ray and compared with the theoretically calculated values. From the electron density distribution, it is shown that the crystal binding of Hg(1-x)Cd(x)Te(MCT) is mainly covalent and has tetrahedron bonds between adjacent atoms.

• Journal of the Korean Institute of Gas
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• v.14 no.2
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• pp.15-21
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• 2010

The demand of gas as an eco-friendly energy source has being increased. With increasing the LPG demand, the number of LPG filling station. In this work, the influence on over-pressure caused by Vapor Cloud Explosion in gas station was calculated by using the Hopkinson's scaling law and injury effect by the accident to a human body was estimated by applying the probit model. As a result of the injury estimation conducted by using the probit model for leakage 10% of 20ton storage tank. The distances from LPG station for death and tympanum rupture are 36.5 and 290 meters, respectively.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.563-570
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• 2016

The composited structural member in which two or more materials having different stress-strain relationships (steel & concrete) has increased greatly in recent years. This paper presents the experimental results of flexural capacity of the composited H-Pile subjected to bending moment. Eight composited beams were tested under direct loading condition using the frame tester. Based on the experimental results it is noted that flexural capacity of composited H-Pile increased about 20~30% and ductility ratio significantly increased. Limit state analysis of the specimens was conducted and the result shows that flexural strength by limit state analysis is conservative.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.253-254
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• 2008

최근 국내 IT 산업의 발달에 따른 디지털화에 따라서 대기전력에 의해서 소비되는 전력소모량은 일반 가정용 전원을 기준으로 할 때 전체 사용량의 11%에 육박하는 수준까지 나타나고 있으며, 이는 다른 선진국에 비해서도 상당히 높은 수준으로 미국의 5% 수준의 2배가 넘는 수치이다. 전기, 전자제품의 디지털화의 추세는 일반가구 및 산업시설에 공급되는 공급전압에 비해서 상당히 낮은 전압으로 제품이 동작하게 되며, 이러한 전압변환은 제품에 내장된 변압기에 의해서 수행되는데, 변압기는 전기 전자제품이 구동하지 않는 경우에도 일차측에 인가된 전압에 의해서 발생되는 대기전력 소비량에 의해서 일정 크기의 전력소모가 지속적으로 이루어지고 있다. 본 인구에서는 대기진력에 대해서 가전제품의 대기상태를 유지하기 위한 상태에선 소모되는 전력량 및 변압기의 1차측에서 유도되나 2차측에서 전력에너지로 변환되지 못하고 소실되는 손실을 모두 포함하는 것으로 정의를 내리고, 해당 적용 제품의 비구동상태에서 독립된 전원으로 구동되어 변압기의 1차 측을 완전히 개방하여 1차 측 전압인가에서 발생되는 손실까지 모두 줄일 수 있는 회로에 대한 기술적인 구성과 적용가능성에 대해서 연구하였다.