• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.123-133
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• 2007

This study analyzed whether a transit network with hierarchy is efficient or not, and if transit network hierarchy has cost efficiency, then which condition guarantees the efficiency of the transit network hierarchy. The authors modeled the total cost of the transit network and suggested the conditions in which the transit network hierarchy has cost efficiency through comparing the cost of the transit network with and without hierarchy. The efficiency of transit network hierarchy is guaranteed when the travel cost savings induced by using a higher hierarchy transit network is larger than the increasing non-travel cost, which is the sum of access cost, waiting cost, and operating cost, induced by the introduction of a higher hierarchy transit network. This result is consistent with common sense and with the concept of cost and benefit analysis. If a passenger traveling within the area divided by a higher hierarchy transit network uses only a lower hierarchy transit network and the passenger traveling out of the area divided by the higher hierarchy transit network uses both lower and higher hierarchy transit networks, the travel demand using the higher hierarchy transit network is inversely proportional to the square of the line spacing. This means that the transit network becomes more efficient and small increases of travel demand guarantee the efficiency of the transit network hierarchy as the connectivity of the network becomes higher. This result shows that transit networks have economies of aggregation. This study is the first analytical research on transit network hierarchy and is expected to be a basis for numerical research. However, numerical research should complement this study, since analytical research has some limitations for considering a real network.

• Journal of the Korea Concrete Institute
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• v.28 no.4
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• pp.473-480
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• 2016

The purpose of this study is to provide analytical method to reasonably evaluate the complicated failure behaviors of shear friction of reinforced concrete shear wall specimens using grade 500 MPa high-strength bars. A total of 16 test specimens with a variety of variables such as aspect ratio, friction coefficient of interface in construction joint, reinforcement details, reinforcement ratio in each direction, material properties were selected and the analysis was performed by using a non-linear finite element analysis program (RCAHEST) applying the modified shear friction constitutive equation in interface based on the concrete design code (KCI, 2012) and CEB-FIP Model code 2010. The mean and coefficient of variation for maximum load from the experiment and analysis results was predicted 1.04 and 17% respectively and properly evaluated failure mode and overall behavior characteristic until failure occur. Based on the results, the analysis program that was applied modified shear friction constitutive equation is judged as having a relatively high reliability for the analysis results.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.146-156
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• 2012

Film was invented by human's desire to copy the real world, starting in the late 19th century. Since the birth of cinema, It was given mission to replay of the real world. On the other hand, cinema was regarded as a fictitious art form. Although the invention of film brought about experience of replaying of the real world it has been reproduced reality with creative story. And it also has been represent reality with sense of reality. Cinema's way of reproduction implied conflicting concept of mimesis. Triple Mimesis of Paul Ricoeur was an idea expanded into an analytical concept from that simple concept of mimesis. The purpose of this study was to examine the prefiguration of shown behavior in Columbine High School massacre based on Triple Mimesis of Paul Ricoeur. It also was to examine a form of representation on cinema which is 'Elephant' and studied how the form of representation on Elephant could interpret by audience. It could be define the relationship between reality and reproduction through this esthetic study. This paper attempted to build the method communication between the originator and audience with a whole analytic process of time and story on the cinematic representation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.273-279
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• 2011

The yield strength of particle-reinforced composites increases as the size of the particle decreases. This kind of length scale has been mainly attributed to the geometrically necessary dislocation punched around the particle as a result of the mismatch of the thermal expansion coefficients of the particle and the matrix when the composites are cooled down after consolidation. In this study, two dislocation-punching theories that can be used in continuum structural modeling are assessed numerically. The two theories, presented by Shibata et al. and Dunand and Mortensen, calculate the size of the dislocationpunched zone. The composite yield strengths predicted by finite element analysis were qualitatively compared with experimental results. When the size of the particle is less than $2{\mu}m$, the patterns of the composite strength are quite different. The results obtained by Shibata et al. are in qualitatively better agreement with the experimental results.

• Composites Research
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• v.13 no.6
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• pp.23-29
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• 2000

The internal residual stresses within the multilayered structure with sharp interface induced by the difference in thermal expansion coefficient between the materials of adjacent layers often provide the source of failure such as delamination of interfaces etc. Recent development of the multilayered structure with functionally graded interface would be the solution to prevent this kind of failure. However a systematic thermo-mechanical analysis is needed for the customized structural design of multilayered structure. In this study, theoretical model for the thermo-mechanical analysis is developed for multilayered structures of the $Al-SiC_p$ functionally graded composite for electronic packaging. The evolution of curvature and internal stresses in response to temperature variations is presented for the different combinations of geometry. The resultant analytical solutions are used for the optimal design of the multilayered structures with functionally graded interface as well as with sharp interface.

• Nuclear Engineering and Technology
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• v.25 no.3
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• pp.430-436
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• 1993

Due to the failure of the instrument and control devices of nuclear power plants caused by aging, nuclear power plants occasionally trip. Even a trip of a single nuclear power plant (NPP) causes an extravagant economical loss and deteriorates public acceptance of nuclear power plants. Therefore, the replacement of the instrument and control devices with proper consideration of the aging effect is necessary in order to prevent the inadvertent trip. In this paper we investigated the optimal replacement periods of the control computer's components of Wolsung nuclear power plant Unit 1. We first derived mathematical models for optimal replacement periods to the digital control computer's components of Wolsung NPP Unit 1 and calculated the optimal replacement periods analytically. We compared the periods with the replacement periods currently used at Wolsung NPP Unit 1. The periods used at Wolsung is not based on mathematical analysis, but on empirical knowledge. As a consequence, the optimal replacement periods analytically obtained and those used in the field show a little difference.

• SUVANNABHUMI
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• v.3 no.2
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• pp.31-77
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• 2011

식민지하 동남아 천년왕국 운동에 대한 오늘날의 해석들은 그 주체인 농민들을 식민주의를 개념화하고 저항하는 동기와 조건 그리고 상징을 제공하는 토착 지식의 전수자로 간주한다. 종말론과 저항에 대한 관심의 대부분은 농민연구나 지역연구 학자들로부터 유래하며, 이들은 봉기에 대한 과거의 묘사들이 토착의 정신세계를 간과했거나 국가이념을 저항세력들의 결집원리로 과대 포장한 것에 주의를 기울인다. 천년왕국 봉기에 관한 글들에서 제공하는 해석들은 동남아 신념 체계에 관한 독립적인 관점을 제공할 뿐만 아니라, 인식론적 측면에서 식민지국가들을 이와 같은 전통에서 단절시키고 있다. 영국 식민지하에서 최대의 농민반란인 서야쌍 봉기(1930-1932)는 오늘날 이와 같은 천년왕국 운동의 정수를 보여주는 사례로 간주된다. 학자들은 수천 명의 농민들로 하여금 버마인의 권위를 되찾고, 불교를 회복시키며, 식민통치로 인해 낳은 사회-경제적 부조리를 일소시킬 그들의 왕으로 믿게 만든 한 농부의 흥미로운 이야기를 묘사하고 있다. 일련의 반란이 미신에 의해 추동되었다고 간주한 식민지 관찰자들과는 달리 이후의 역사가들은 그 반란이 불교를 재건하고 태평성대로 인도할 미래부처인 미륵불의 현신에 대한 믿음의 표현이라고 해석했다. 이러한 학자들에게 서야쌍 봉기는 어떻게 동남아 사람들의 감수성이 식민지의 사회-경제적 압력 속에서도 지속되었으며, 상좌불교의 예언이 토착의 문화적 토양에 얼마나 깊이 내재해 있는지를 말해주는 사례였다. 경험적 관점에서 본 글은 서야쌍 봉기의 근원을 재해석함으로써 천년왕국 봉기에 관한 글들이 대부분 식민지적 문서화 작업과 종교를 과장되고 세속화된 화술로 믿게 하려고 지역연구자들의 산물임을 밝히고 있다. 개념적 관점에서 본고는 버마에서 일어난 천년왕국 운동의 역사적 구성에 대한 식민주의의 역할을 보다 면밀히 관찰하였다. 또한 식민지법, 학문, 그리고 식민지하 버마 농촌에서 발생한 종교적 저항에 대한 우리들의 이해를 상호 연결하는 인식론적 관계를 탐구했다. 그리하여 본고는 천년왕국 해석이 이 시기에 공존했던 다른 유형의 불교정치적 형태를 어떻게 왜곡했는가를 밝히고 있다.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.337-342
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• 2018

This study was started to study the artistic aesthetic value of the antique artwork which is gradually declining in the field of metal crafts. The aesthetic interpretation of the lines and faces that have been identified through previous researches has been defined as a vitality and repetitive beauty. The researchers here have tried to express the formative works which can be repeated and change. As a result, it was found that the object of inquiry which can express the aesthetic beauty felt in the simple change of the line and the face is possible without the advanced technique of the difficult technique or the molding method through the natural and gradual change of the line and the face rather than the regular repetition. Through this study, it was found that the use of future lines and surfaces could be utilized as a variety of aesthetic expression methods as molding elements.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.610-610
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• 2012

한강하구는 국가하천인 한강, 한강의 1지류인 임진강과 북한 황해도의 예성강이 만나 한강하류 수역을 형성하여 서해 중부해역과 합류하여 매우 복잡한 수리학적 특성을 지닌다. 또한 한강하구의 경우 교량, 수중보 등의 하천 구조물이 설치되어 있다. 수리학은 크게 수위와 관계되는 현상, 하상변화와 관계되는 현상, 외부 환경과 관계되는 현상으로 살펴 볼 수 있다(최계운, 2005). 하천구조물이 설치됨에 따라 구조물 주변에서 국부적으로 수위가 상승되거나 유속이 변화, 세굴현상 등의 하상 변화, 구조물 설치에 따른 생태계의 단절 현상 등 수리학적 현상에 영향을 미치게 된다. 한강하구는 이러한 복잡한 흐름현상에 더해 군사적으로 민감한 지역의 특성으로 현장의 접근성에 한계가 있어 이 지역의 연구조사는 더욱 어렵다. 그간 한강하구의 흐름 현상을 규명하기 위한 연구 방법으로 수치모의를 통한 다양한 연구가 진행되어 왔다. 수리학적 흐름 현상을 계산하기 위한 필수 조건인 하류경계조건 설정에도 어려움이 수반된다. 이 때문에 한강의 수리학적 수치모의 실험에 관한 연구들은 한강하구의 얕은 수심과 해석의 공간적 범위를 소홀히 하고, 공릉천 합류부를 기준으로 하류지점에 대해서는 인천 조위관측소의 조위자료를 사용하거나 하천정비기본계획상의 기점수위를 일괄적으로 적용하여 지점에 따른 수위의 차이를 적용하지 못하는 한계를 지닌다. 따라서 본 연구에서는 남북접경지역 접근의 어려움으로 인하여 발생되는 한강하구 흐름해석의 불확실성을 명확히 하기 위한 방안으로 한강하구지역에 해당 군부대와 군사정전위원회의 출입허가 승인을 얻어 현장조사를 실시하였다. 사전조사를 통하여 성동교, 대산교, 공릉천, 화도돈대, 철곶돈대 전방 수변, 애기봉전망대 전방 수변을 조사 지점으로 선정하였다. 기존 연구에서는 한강하구의 공릉천 합류부 지점을 하류경계조건으로 채택하고 있으나, 현장조사를 통하여 얻을 자료를 분석한 결과 공릉천 합류부 지점의 수위는 강우발생에 대한 하천의 영향을 받는 것으로 나타나 하류경계조건으로 적정하지 않은 것으로 판단되었으며, 공릉천보다 하류지역에 위치한 지역에 대하여 하류경계조건으로 적정한 지역을 찾을 수 있었다. 수치해석 시에는 공간적 범위와 연구의 목적을 고려하여 각 지점의 실제 관측 자료를 활용한 경계조건을 사용하는 것이 적합한 것으로 판단되며 보다 많은 현장조사와 특성분석을 통한 정확한 경계조건의 구축이 필요할 것으로 사료된다.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.4
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• pp.341-348
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• 2010

The basic principle of fry drying process of sludge lies in the rapid pressure change of sludge material caused by the change of temperature between oil and moisture due to the difference of specific heat. Therefore, the rapid increase of pressure in drying sludge induces the efficient moisture escape through sludge pores toward heating oil media. The object of this study is to carry out a systematic investigation of the influence of various parameters associated with the sludge fry drying processes on the drying efficiency. To this end, a series of parametric experimental investigation has been made together with the numerical calculation in order to obtain typical drying curves as function of important parameters such as drying temperature, sludge diameter, oil type and sludge type. In the aspect of frying temperature, especially it is found that the operation higher than $140^{\circ}C$ was favorable in drying efficiency regardless of type of waste oil employed in this study. The same result was also noted consistently in the investigation of numerical calculation, that is, in that the sludge particle drying was efficiently made over $140^{\circ}C$ irrespective of the change of particle diameter. As expected, in general, the decrease of diameter in sludge was found efficient both experiment and numerical calculation in drying due to the increased surface area per unit volume. In the investigation of oil type and property, the effect of the viscosity of waste oil was found to be more influential in drying performance. In particular, when the oil with high viscosity, a visible time delay was noticed in moisture evaporation especially in the early stage of drying. However, the effect of high viscosity decreased significantly over the temperature of $140^{\circ}C$. There was no visible difference observed in the study of sludge type but the sewage sludge with a slightly better efficiency. The numerical study is considered to be a quite useful tool to assist in experiment with more detailed empirical modeling as further work.