• 한국구조물진단유지관리공학회 논문집
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• 제9권4호
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• pp.243-251
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• 2005

본 연구에서는 골조튜브 및 가새튜브시스템의 60층 철골구조물에 말뚝-지반간의 상대변위를 고려한 p-y 스프링 계수를 지반의 깊이별로 적용시키는 방법과, 지반 및 기초를 나타내는 6개의 선형 스프링 계수를 구조물 하부에 적용시키는 방법을 사질토와 점성토에 적용하여 지반 연성을 고려하는 고층 구조물의 지진해석을 수행하였다. 각 경우에 대한 횡변위 및 층간변위, 최대응력, 주기 및 1차 모드 질량참여율을 비교하여 지반-구조물 상호작용에 따른 고층 구조물의 거동을 분석하였고, 그 결과 건축구조설계에서 지반-구조물의 상호작용에 대한 고려가 중요 변수임을 확인하고, 구조시스템 변화에 따른 지반-구조물 상호작용의 영향을 알아보았다.

• 한국지진공학회논문집
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• 제24권4호
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• pp.179-187
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• 2020

Seismic qualification of equipment including piping is performed by using floor response spectra (FRS) or in-structure response spectra (ISRS) as the earthquake input at the base of the equipment. The amplitude of the FRS may be noticeably reduced when obtained from coupling analysis because of interaction between the primary structure and the equipment. This paper introduces a method using a modal synthesis approach to generate the FRS in a coupled primary-secondary system that can avoid numerical instabilities or inaccuracies. The FRS were generated by considering the dynamic interaction that can occur at the interface between the supporting structure and the equipment. This study performed a numerical example analysis using a typical nuclear structure to investigate the coupling effect when generating the FRS. The study results show that the coupling analysis dominantly reduces the FRS and yields rational results. The modal synthesis approach is very practical to implement because it requires information on only a small number of dynamic characteristics of the primary and the secondary systems such as frequencies, modal participation factors, and mode shape ordinates at the locations where the FRS needs to be generated.

• 복식
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• 제60권10호
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• pp.88-99
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• 2010

The purpose of this study is to express visual and functional diversity through modifiable design, and to suggest a methodological model. With this view, this study was aimed to departmentalize the case of knitwear in modifiable design of clothes and propose the possibility of variable knit fashion through make the most of knit's characteristics. Four wearable physical clothes using the most of flexible knits' characteristics were made for this study based on the modifiable design on the expressive tendency and analysis of plasticity. The following results were obtained. First, as modifiable knit design can create effects of several dresses in visual aspect and functional aspect, so it has practicality and functionality. Because modifiable clothes required wearer's participation, this have amusement that give enjoyment and freshness to wearer. Second, in mode of wearing, flexibility of knit is suitable character to open & close and change of wearing position. In manipulation, a prearranged plan for line of clothes and good choice of subsidiary materials are important. Third, the characteristics of knits allow using and mixing with different pattern and materials on the two sides of the same cloths except for the some of the parts. Moreover, there is no unraveled thread on the part of knits margin against woven, so it has the broad applicable range for the changeable design. Finally, the form and function, a prearranged plan for modifiable design of clothes have all contributed in creating new structure and patterns in design.

• 대한전기학회논문지:전력기술부문A
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• 제50권1호
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• pp.13-19
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• 2001

This paper deals with decentralized control scheme and its application to multi-machine power systems. Decentralized control scheme has several practical advantages, because power system has geographically distributed characteristics. In this paper, decentralized observer-based optimal Power System Stabilizer(PSS) and Thyristor-Controlled Series Capacitor(TCST) controller are designed and tested in WSCC 9 bus system with one TCSC installed. Simulation results show that the proposed decentralized controller has satisfactory performances comparable to the centralized controller. In addition, using modal analysis, this paper shows that the proposed decentralized controller significantly affects only one pair of eigenvalues which have high participation with each generator, while slightly affects other eigenvalues. This result indicates that the application of the decentralized control scheme to enhance power system dynamic stability via excitation control have potential advantages because each low-damped mode occurs dominantly by each decentralized subsystem.

• Human Ecology Research
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• 제59권1호
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• pp.99-112
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• 2021

This study develops and applies a service learning course that integrates university curriculum with the local community in housing and interior design. The results of the study are as follows. First, the service learning course of the housing and interior design was developed as a six-week lecture based on the project model with the theme of housing for the socially disadvantaged. Second, this course was implemented with faculty, students, interior designers, and service recipients to engage in activities to improve the educational environment of local child centers. Next, students engaged in the service learning course and continuously conducted reflection activities to enhance the effectiveness of learning. In reflection activities, students assessed that self-directed capabilities increased as has employing the coordination and applicability to meet identified community needs. Finally, faculty, students, and experts (including institutional experts and supervising departments) evaluated course practice and educational outcomes. Experts assessed that the course clarified course objectives, utilized various learning strategies, and showed that the structural reflection mode of learners and professors was overwhelmingly positive. The results indicated that service-learning courses enable students to integrate academic study with social work to better understand course content through direct engagements in experience learning. Furthermore, students are empowered by participation in public services that benefit service clients and consultants as students take more personal responsibility for learning.

• Advances in materials Research
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• 제11권1호
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• pp.59-73
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• 2022

In the construction industry, thin-walled frame elements with very slender open cross-sections and low torsional stiffness are often subjected to a complex loading condition where axial, bending, shear and torsional stresses are present simultaneously. Hence, these often fail in instability even before the yield capacity is reached. One of the most common instability conditions associated with thin-walled structures is Lateral Torsional Buckling (LTB). In this study, a first order Generalized Beam Theory (GBT) formulation and numerical analysis of cold-formed steel lipped channel beams (C80×40×10×1, C90×40×10×1, C100×40×10×1, C80×40×10×1.6, C90×40×10×1.6 and C100×40×10×1.6) subjected to uniform moment is carried out to predict pure Lateral Torsional Buckling (LTB). These results are compared with the Finite Element Analysis of the beams modelled with shell elements using ABAQUS and analytical results based on Euler's buckling formula. The mode wise deformed shape and modal participation factors are obtained for comparison of the responses along with the effect of varying the length of the beam from 2.5 m to 10 m. The deformed shapes of the beam for different modes and GBTUL plots are analyzed for comparative conclusions.

• Structural Engineering and Mechanics
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• 제85권5호
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• pp.655-664
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• 2023

Reinforced concrete (RC) shear wall structures are one of the most widely used structural systems to resist seismic loading all around the world. Although there have been several efforts to provide conceptually simple procedures to reasonably assess the seismic demands of structures over recent decades, it seems that lesser effort has been put on a number of structural forms such as RC shear wall structures. Therefore, this study aims to represent a simple linear response spectrum-based method which can acceptably predict the nonlinear displacements of a non-ductile RC shear wall structure subjected to an individual ground motion record. An effective period and an equivalent damping ratio are introduced as the dynamic characteristics of an equivalent linear SDOF system relevant to the main structure. By applying the fundamental mode participation factor of the original MDOF structure to the linear spectral response of the equivalent SDOF system, an acceptable estimation of the nonlinear displacement response is obtained. Subsequently, the accuracy of the proposed method is evaluated by comparison with another approximate method which is based on linear response spectrum. Results show that the proposed method has better estimations for maximum nonlinear responses and is more utilizable and applicable than the other one.

• Educational Technology International
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• 제7권1호
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• pp.1-20
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• 2006

This paper describes practical research on the improvement of teaching and learning process by integrating Web Bulletin Board (WBB) and mobile phone. This paper addresses three topics; A) the interactive lecture with topics-based discussions using the Web Bulletin Board (WBB) as a tool for assisting discussion, B) the introduction of peer evaluation among students to develop their problem-solving and cognitive skills, C) the use of mobile phones for promoting interactive lectures, keeping class attendance, conducting assignments, and providing notices for the next class. Results indicated the following research-findings: (1) WBB plays a role in facilitating positive participation in classes. (2) In contrast to the scenario of the traditional mode of instruction (without the usage of WBB), students were able to deepen their understanding of the theme by accessing the WBB before and after classes. (3) Peer evaluation highly promoted students' motivation to learn, and was effective in cultivating meta-cognition through modeling. (4) Mobile phone was identified as a highly effective tool for keeping class attendance, realizing interactive classes by generating discussions, and managing assignments and homework.

• 대한교통학회지
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• 제24권5호
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• pp.89-108
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• 2006

우리나라도 2000 년에 65세 이상 고령자 인구가 전인구의 7%에 도달하며서 소위 고령화 사회에 진입하게 되었고 앞으로 25년간 우리나라 고령자인구의 증가율은 세계적으로 유례없이 급속할 것으로 예상된다. 이러한 측면에서 최근 고령화 문제가 사회적인 이슈로 대두됨에 따라 교통시설물 계획 등에서 고령인구의 통행특성을 고려한 계획 및 설계가 필수적으로 요구되어지고 있다 하지만, 기존의 교통존 혐의 집계분석 방법론에서는 일반인과 고령자의 평균값을 사용함으로써 고령자의 통행 특성 및 사회경제적 특성을 고려하는데 한계를 가지고 있다. 따라서 본 연구는 일반인과 다른 고령자의 통행특성을 분석하기 위해 네스티드 로지모형을 이용하여 개인의 통행특성을 반영할 수 있는 비집계분석의 방법론으로 활동 스케줄링 모형을 구축하고 정립하였다. 본 연구에서의 분석결과 일반인과 비교해 고령자의 통행특성은 직장인과 비직장인 모두에서 출발시간과 수단 선택에서 큰 차이를 가지는 것으로 분석되었다 이러한 개인 통행특성의 차이를 간과한 기존의 교통존 중심의 집계분석 방법론으로 장래 수요 예측시에 큰 편이를 초래할 것으로 예상된다 따라서 본 연구는 개인통행특성을 고려하기 위해 활동기반모형의 필요성을 강조할 수 있는 좋은 선행과제가 될 것으로 기대한다 또한, 활동기반분석의 지속적인 연구 및 이에 대한 개발은 현재 대두되고 있는 도로사업 평가의 신뢰성, 향후교통시설물 계획 및 설계 평가에 중요 요소로 인식되는 교통량 예측 등에 대한 신뢰성 향상에 많은 기회를 할 것으로 판단된다

• 한국ITS학회 논문지
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• 제15권5호
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• pp.1-11
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• 2016

본 연구는 고령자와 임산부 등 교통약자의 이동권 증진과 사회참여 여건 확대 측면에서 운영 중인 특별교통서비스(이하 STS)의 이용증진 기여를 목적으로 한다. 이를 위해 수원시에서 운영 중인 STS시스템의 이용자 DB를 분석하였으며, 고령자와 임산부 이용자 대상의 진술 선호도를 조사하였다. 구체적으로는 STS 중심의 선호도 모형을 구축하고, 그 영향인자들을 비교하여 STS의 이용 활성화 방안을 모색하였다. 연구결과, STS 이용자의 약 23%는 고령자와 임산부이며, 병원 통행목적의 이용자는 31%, 2~5km의 단거리 통행자는 70% 수준인 것으로 나타났다. STS와 버스 대상의 진술 선호도 조사결과, 고령자의 경우 통행요금이 가장 영향력 있는 인자이며 연령이 많을수록 STS를 선호하는 것으로 확인되었다. 임산부의 경우 통행시간과 통행요금이 수단선택의 주요 영향인자이며, 통행빈도가 많을수록 STS를 선호하는 것으로 확인되었다. 그리고 STS의 이용요금이 일반택시 요금의 약 70% 수준일 경우, 고령자와 임산부의 버스 대비 STS 분담률은 각 51.1%, 63.6%으로 분석되어, STS 이용 활성화를 위한 이용요금 조정은 효과적인 것으로 확인되었다. 본 연구결과는 STS의 합리적인 요금체계를 정립하기 위한 근거로 활용될 수 있으며, 고령자와 임산부의 STS 이용을 증진하여 고령자의 승용차 운전에 따른 교통사고 감소 및 임산부의 버스 이용에 따른 위험성 예방에 기여할 것으로 기대된다.