• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.177-177
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• 2011

현재 대부분 사용되는 지하매설물용 뒤채움재는 다짐공법을 많이 사용하고 있으며, 실제로 이러한 방법은 부적절한 다짐으로 인해 침하 및 내구성 저하로 인해 파손을 초래하는 경우가 많다. 이러한 문제를 해결 할 수 있는 하나의 대안으로 유동성 뒤채움재를 이용할 수 있다. 유동성 뒤채움재는 초기 유동성, 시간에 따른 자기 강도 발현 무다짐공법 적용 등 많은 장점을 가지고 있다. 본 연구에서는 현장발생토사, 정수장슬러지 및 폐타이어분말 등 재활용 재료를 이용한 유동성 뒤채움재의 기본물성을 평가하였다. 각각의 재활용재료에 대한 입도 및 비중을 평가하였고, 최적배합설계를 결정하였으며, 모형 시험과 유한요소 해석을 위한 기본 물성값을 위해 일축압축시험, 삼축압축시험, 공진주시험 등을 수행하였다. 최적배합설계를 산정하는 과정에서 수행한 실험중 대표적인 시험으로 자가수평능력 및 자기다짐등에 필요한 유동성을 판단하는 Flow시험(ASTM D 6133) 결과 기준으로 정한 20cm이상의 값을 얻을 수 있었으며 일축압축강도의 경우 시공 후 유지 보수가 용이한 강도인 $3.0kg/cm^2{\sim}5.6kg/cm^2$이하로 설계하였으며 28일재령 일축압축강도 결과 $3.15{\sim}3.74kg/cm^2$라는 유지보수에 적당한 결과값을 나타내었다. 이 배합이 현장에서 사용이 가능하다는 것으로 판단하고 현장모형시험과 유한요소해석를 통하여 현장에서 사용하였을 때 관의 변형과 관에 작용하는 하중변화를 확인하고 현장모형시험과 유한요소해석 간의 상관관계를 규명하였다. 현장 모형 시험은 현장과 비슷하게 제작된 모형을 이용하였으며 최대한 현장과 비슷한 조건에서 뒤채움재를 타설과정 중과 타설이 완료된 상태에서 7일 양생 후 하중재하와 같이 두가지 경우에서 수직 수평토압, 관의 수직 수평변위, 관의 종단변형을 측정하였다. 유한요소해석 프로그램은 Midas GTS를 이용하여 실시하였으며 관의 변형률, 유효응력을 측정하여 규명하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.195-196
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• 2014

취업열기가 뜨거워지고 있는 가운데 취업시장의 문턱에 들어서는 학생들은 본인의 이력관리를 위해 수많은 노력을 하고 있다. 이 시스템은 교내의 모든 학생들이 미래 직업을 준비할 수 있도록 하고 학교생활을 하는 과정에서 자기성찰의 기회를 제공하여 자기 계발 방향을 찾도록 하는 것이 주된 목적이다. 따라서 본 시스템은 취업시장의 문화를 혁신하고자 하는데 목적이 있다. 본 개발 시스템은 학생의 대내외적인 활동에 활용되는 모든 자료를 체계적으로 정리 및 관리할 수 있는 시스템으로 대학에서 취업을 목적으로 진행하는 프로젝트 관련수업의 결과물과 포트폴리오 관리에 목표를 두고 주로 학생의 취업연계 기능에 초점을 맞추어 개발되었다. 학생들은 학생간의 포트폴리오 정보를 공유하고 해당 시스템의 평가모듈을 통해 교수의 조언과 평가를 받아 보다나은 결과물을 창출 할 수 있다. 이렇게 학생, 교수, 기업이 서로 의사교류를 통해 원만한 관계를 유지할 수 있으며 학생과 기업 간의 win-win 효과를 얻을 수 있다.

• Korean Journal of Culture and Social Issue
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• v.19 no.2
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• pp.203-234
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• 2013

This study was performed to clarify 'jajonshim' which is different from self-esteem in its social representation and concept in Korean society. In order to refine the notion of 'jajonshim', we first referred to literature and short essay on jajonshim and analyzed its cultural meaning and social representation in Korea. As a result, jajonshim was considered necessary condition for human beings in Korean culture. Although jajonshim was not well recognized normally, it became critical when it was threatened by others and considered to be what one must save as well. Furthermore, the ground theory designed by Strauss and Corbin was utilized in order to analyze Korean interviewees' experience of jajonshim. Koreans believed that their jajonshim was injured when others disrespected their values, which consequently produced negative emotions. When their jajonshim was damaged, people also used 3 coping strategies to recover it. Based on the results, jajonshim was distinguished from self-esteem. First, jajonshim is a type of self-awareness people experience when they are disrespected; thus, it is different from self-esteem which is maintained stable regardless of any events or situations. Second, unlike self-esteem which is solely evaluated by oneself, jajonshim is evaluated by other people's point of view. This study shows that jajonshim exists in the context of Korean culture and has significance in clarifying the cognitive structure and experience process of jajonshim.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.126-135
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• 2013

Recently, mass concrete with high flowability are widely used to improve the quality and constructability in the longer span construction of prestressed concrete bridges, but it may induce nonstructural cracks due to the hydration heat and autogenous shrinkage etc. The stresses in concrete were evaluated by various experiments and numerical analysis. The tensile stress in mass concrete was increased in connection with the accumulation of hydration heat. Moreover, large amount of autogenous shrinkage from powder type admixture could add the tensile stress to mass concrete near anchorage zone. The tensile stresses in anchorage zone by heat and autogenous shrinkage exceeded the tensile strength of early stage of concrete, and small amounts of stress increasement were shown in other parts of PSC girder.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.125-132
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• 2020

The causes of concrete shrinkage are very diverse, in particular, aggregates impact the characteristics of shrinkage in concrete by constraining the shrinkage of cement paste. Meanwhile, owing to the lack of natural aggregate, various alternative aggregates are being developed, and their application in concrete also becomes more diverse. This study aimed to experimentally evaluate the drying and autogenous shrinkage in concrete that was composed of electric arc furnace slag as coarse aggregates. And, the results were compared with prediction models. From the results, the application of electric arc furnace slag can reduce the drying and autogenous shrinkage. In particular, autogenous shrinkage is greatly decreased. The predictions using GL2000 for drying shrinkage and Tazawa model for autogenous shrinkage were similar to the experimental results. However, the most prediction models do not consider the impact of aggregates, hence, the new prediction model should be developed or improved.

• Journal of the Korean Magnetics Society
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• v.24 no.3
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• pp.86-89
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• 2014

Anisotropic bonded magnet is composed of magnetic powder and organic binder. organic binder in bonded magnet, serves to orientation of the powder. organic binder is composed of polymer resin, lubricant, hardener and coupling agent, etc.in this study, selection of the various components to producing an organic binder and by adjusting the composition ratio and concentrate, apply to bonded magnet for producing an organic binder that suitable for magnetic powder. so evaluation of magnetic properties and mechanical properties, the organic binder ratio and component was confirmed to suitable for bonded magnet.

• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.123-134
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• 2005

This research aims at developing a new method which can replace the existing method. known as the quality factor(Q factor) method by an L-R-C test for use in the performance test of inductive loop detectors(ILD) being installed and maintained. In this study, a sensor to detect a magnetic field in terms of frequency and intensity, a method to collect field data, the method of analysis, and the method of diagnosis were developed. An automatic diagnosis system which was developed to overcome those drawbacks has the following features : First, field data is collected automatically by a test vehicle equipped with magnetic field sensors that is running can be said to along the roadway and. thus, the new system completely overcome the roadway and, thus, the new system can be said to completely overcome the inefficiency of the existing method second, since the magnetic fold generated from the ILD is the final output of the whole system of ILD, the existing problem has been solved. third. since each of the detection area by height is collected by the magnetic sensors installed by height. a basic for the identification of the vehicle types to be detectable and the setting of adjustment factors has been made. For the automatic diagnosis system developed during in this study, a reliability test was carried out by comparing vehicle times of ILD installed ideally.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.12
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• pp.1258-1268
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• 2014

In this paper, we propose and design IBFD system based on DCR. And then, we analyze effect of DC offset by self-interference in the proposed system. Also, we evaluate BER performance of the proposed system according to DC offset. As a result of the simulation, we can confirm that when the self-interference is not completely cancelled by the RF cancellation, linearity of desired signal and self-interference is distorted by DC offset. Also, in the proposed system using m-QAM modulation, DC offsets of multi-level are caused by self-interference with m-QAM modulation. As a result, constellations of desired signal and self-interference are greatly distorted. In contrast, in the proposed system using m-PSK modulation, DC offset of single level is caused by self-interference with m-PSK modulation. In this condition, we confirm that distortion of constellations of desired signal and self-interference is less than when using m-QAM modulation. That is, we can confirm that m-PSK modulation is effective than m-QAM modulation in DCR based IBFD system. Also, we can confirm that it is important to cancel self-interference as much as possible in RF-stage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3587-3598
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• 2014

This study analyzed the efficiency of a program designed for enforcing the job-seeking ability to overcome the career-barriers as well as the effect of the job-seeking efficacy toward the job-maintaining willingness of the disabled. For this research, the job-seeking ability enforcement program, which was started by the Korea Employment Agency for the Disabled, was executed towards the 86 disabled by 7 sessions, which has been operated 6 hours a day for 4 days per week from December in 2012 to November in 2013. The survey for the study was taken twice with the same questionnaire toward the same object; one was a pre-survey that has been done before operating the program and the other was a pro-survey that was done after operating the program. The data was analyzed to obtain the 4 variables of job-seeking efficacy to overcome the career-barriers, which were self-efficacy, job-seeking skill, interpersonal relationship skill and job-information exploration and the 5th variable, job-maintaining willingness. The study findings were as follows. Firstly, the program efficiency was significant in interpersonal relationship skill and job-information exploration, while not significant in self-efficacy and job-seeking skill. Secondly, the self-efficacy and interpersonal relationship skill among the job-seeking efficacy to overcome career-barriers positively affects the job-maintaining willingness.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.33.2-33.2
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• 2011

CMP (Chemical-Mechanical Planarization) 공정이란 화학적 반응과 기계적 힘을 동시에 이용하여 표면을 평탄화하는 공정으로, 반도체 산업에서 회로의 고집적화와 다층구조를 형성하기 위해 CMP 공정이 도입되었으며 반도체 패턴의 미세화와 다층화에 따라 CMP 공정의 중요성은 더욱 강조되고 있다. CMP 공정은 압력, 속도 등의 공정조건과, 화학적 반응을 유도하는 슬러리, 기계적 힘을 위한 패드 등에 의해 복합적으로 영향을 받는다. CMP 공정에서, 폴리우레탄 패드는 많은 기공들을 포함한 그루브(groove)를 형성하고 있어 웨이퍼와 직접적으로 접촉을 하며 공정 중 유입된 슬러리가 효과적으로 연마를 할 수 있도록 도와주는 역할을 한다. 하지만, 공정이 진행 될수록 그루브는 손상이 되어 제 역할을 하지 못하게 된다. 패드 컨디셔닝이란 컨디셔너가 CMP 공정 중에 지속적으로 패드 표면을 연마하여 패드의 손상된 부분을 제거하고 새로운 표면을 노출시켜 패드의 상태를 일정하게 유지시키는 것을 말한다. 한편, 금속박막의 CMP 공정에 사용되는 슬러리는 금속박막과 산화반응을 하기 위하여 산화제를 포함하는데, 산화제는 금속 컨디셔너 표면을 산화시켜 부식을 야기한다. 컨디셔너의 표면부식은 반도체 수율에 직접적인 영향을 줄 수 있는 scratch 등을 발생시킬 뿐만 아니라, 컨디셔너의 수명도 저하시키게 되므로 이를 방지하기 위한 노력이 매우 중요하다. 본 연구에서는 컨디셔너 표면에 연마 잔여물 흡착을 억제하고, 슬러리와 컨디셔너 표면 간에 일어나는 표면부식을 방지하기 위하여 소수성 자기조립 단분자막(SAM: Self-assembled monolayer)을 증착하여 특성을 평가하였다. SAM은 2가지 전구체(FOTS, Dodecanethiol를 사용하여 Vapor SAM 방법으로 증착하였고, 접촉각 측정을 통하여 단분자막의 증착 여부를 평가하였다. 또한 표면부식 특성은 Potentiodynamic polarization와 Electrochemical Impedance Spectroscopy (EIS) 등의 전기화학 분석법을 사용하여 평가되었다. SAM 표면은 정접촉각 측정기(Phoenix 300, SEO)를 사용하여 $90^{\circ}$ 이상의 소수성 접촉각으로써 증착여부를 확인하였다. 또한, 표면에너지 감소로 인하여 슬러리 내의 연마입자 및 연마잔여물 흡착이 감소하는 것을 확인 하였다. Potentiodynamic polarization과 EIS의 결과 분석으로부터 SAM이 증착된 표면의 부식전위와 부식전류밀도가 감소하며, 임피던스 값이 증가하는 것을 확인하였다. 본 연구에서는 컨디셔너 표면에 SAM을 증착 하였고, CMP 공정 중 발생하는 오염물의 흡착을 감소시킴으로써 CMP 연마 효율을 증가하는 동시에 컨디셔너 금속표면의 부식을 방지함으로써 내구성이 증가될 수 있음을 확인 하였다.