• 대한인간공학회지
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• 제12권1호
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• pp.17-24
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• 1993

Today, rapid development and timeliness of introducing a new product be- comes a more influencing factor of determing its competitive power due to a shortened product cycle, while rapid improvement of manufacturing technology makes product design and manufacturing fuse together. This implies that prod- uct usability evaluation and improvement starts right from its design phase, resulting in less development time and cost. To make this possible, proper as- sessment of human reach is one of essential functions for ergonomic product us- ability evaluation, specifically in the platform of computer-aided ergonomic evaluation models or any CAD system with a built-in man model. In this study, an analytic reach prediction algorithm ensuring the posture that human naturally takes, is presented by employing the methods developed for robot kinematics. Among robot kinematic methods for solving the multi-link system, the resolved motion method was found to be effective to solve human reach as a redundant manipulator model. Also, the joint range availability was used as a performance fonction to guarantee human naturalness. The result is expected to be directly applicable to product usability evaluations.

• Smart Structures and Systems
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• 제23권4호
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• pp.329-335
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• 2019

Structural fuses are made up from oriented steel plates to be used to resist seismic force with shear loading resistance capabilities. The damage and excessive inelastic deformations are concentrated in structural fuses to avoid any issues for the rest of the surrounding elements. Recently developed fuse plates are designed with engineered cutouts leaving flexural or shear links with controlled yielding features. A promising type of link is proposed to align better bending strength along the length of the link with the demand moment diagram is a butterfly-shaped link. Previously, the design methodologies are purely based on the flexural stresses, or shear stresses only, which overestimate the dampers capability for resisting against the applied loadings. This study is specifically focused on the optimized design methodologies for commonly used butterfly-shaped dampers. Numerous studies have shown that the stresses are not uniformly distributed along the length of the dampers; hence, the design methodology and the effective implementation of the steel need revisions and improvements. In this study, the effect of shear and flexural stresses on the behavior of butterfly-shaped links are computationally investigated. The mathematical models based on von-Mises yielding criteria are initially developed and the optimized design methodology is proposed based on the yielding criterion. The optimized design is refined and investigated with the aid of computational investigations in the next step. The proposed design methodology meets the needs of optimized design concepts for butterfly-shaped dampers considering the uniform stress distribution and efficient use of steel.

• 한국항행학회논문지
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• 제23권4호
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• pp.328-332
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• 2019

웹 기술의 발전으로 다양한 시스템 환경에서의 기술적 융합을 웹 인터페이스를 통해 수행이 가능해졌다. 웹은 그 역할에 따라 웹 1.0시대부터 4.0시대로 분류할 수 있으며, 정보의 연결 (connects information), 사람의 연결(connects people), 지식의 연결(connects knowledge), 지능의 연결(connects intelligence)의 특성을 갖는다. 또한, 4차 산업혁명을 거치면서 모바일 앱을 통한 다양한 기술적 needs가 발생하였고, 단순한 정보의 제공 수단이던 웹에서, 3D, 가상/증강, 비디오/오디오 프로세싱 등의 기능 수행이 가능해졌다. 이러한 시대적 needs를 뒷받침하기 위한 기술 표준이 연구되었다. 본 논문에서는 그중 하나인 웹 어셈블리에 대해 분석하였다. 웹 어셈블리를 기존의 웹 시스템(혹은 플랫폼)과 연계, 융합하여 활용하는 방안에 대해 살펴보고, 다양한 사례를 통해 기술적 의미를 분석 한다. 또한, 기존의 자바스크립트와 웹 어셈블리를 융합할 수 있는 아키텍트에 대한 연구를 진행하고, 추후 연구방향에 대해 논하고자 한다.

• Steel and Composite Structures
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• 제19권5호
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• pp.1167-1184
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• 2015

Despite considerable life casualty and financial loss resulting from past earthquakes, many existing steel buildings are still seismically vulnerable as they have no lateral resistance or at least need some sort of retrofitting. Passive control methods with decreasing seismic demand and increasing ductility reduce rate of vulnerability of structures against earthquakes. One of the most effective and practical passive control methods is to use a shear panel system working as a ductile fuse in the structure. The shear Panel System, SPS, is located vertically between apex of two chevron braces and the flange of the floor beam. Seismic energy is highly dissipated through shear yielding of shear panel web while other elements of the structure remain almost elastic. In this paper, lateral behavior and related benefits of this system with narrow-flange link beams is experimentally investigated in chevron braced simple steel frames. For this purpose, five specimens with IPE (narrow-flange I section) shear panels were examined. All of the specimens showed high ductility and dissipated almost all input energy imposed to the structure. For example, maximum SPS shear distortion of 0.128-0.156 rad, overall ductility of 5.3-7.2, response modification factor of 7.1-11.2, and finally maximum equivalent viscous damping ratio of 35.5-40.2% in the last loading cycle corresponding to an average damping ratio of 26.7-30.6% were obtained. It was also shown that the beam, columns and braces remained elastic as expected. Considering this fact, by just changing the probably damaged shear panel pieces after earthquake, the structure can still be continuously used as another benefit of this proposed retrofitting system without the need to change the floor beam.

• Applied Microscopy
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• 제28권1호
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• pp.73-82
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• 1998

본 연구에서는 급속동결 deep etching법을 이용하여 흰쥐에서 담세관주위세포질에 있는 미세사와 용해소체 및 소포등 세포내소기관들이 어떻게 담즙분비에 관여하는지를 알아 보고자 하였다. Taurocholic acid를 투여한 군은 정상군에 있어서와 같이 미세사가 담세관 주위를 둘러싸면서 담세관 원형질막과 다른 세포내소기관에 부착되어 있었다. 이들 담세관 주위의 미세사들은 미세융모속에서 다발을 이루고 있었으며 담세관 둘레에서는 관주위직을 형성하면서 연접복합체에 결합되어 있었다. 미세사는 또한 담세관 원형질막과 소포사이에 걸쳐있는 것도 관찰되었다. 이상의 소견으로 미루어 미세사는 담세관에서의 담즙의 분비를 돕는 소기관임을 알 수 있는데 특히 담세관에 융합할 수 있도록 소포의 전위를 유도하는 기구로서 작용할 것으로 추정된다.

• Steel and Composite Structures
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• 제42권4호
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• pp.539-552
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• 2022

Concentrically braced frames (CBFs) possess high stiffness and strength against lateral loads; however, they suffer from low energy absorption capacity against seismic loads due to the susceptibility of CBF diagonal elements to bucking under compression loading. To address this problem, in this study, an innovative damper was proposed and investigated experimentally and numerically. The proposed damper comprises main plates and includes a flange plate angled at θ and a trapezius-shaped web plate surrounded by the plate at the top and bottom sections. To investigate the damper behaviour, dampers with θ = 0°, 30°, 45°, 60°, and 90° were evaluated with different flange plate thicknesses of 10, 15, 20, 25 and 30 mm. Dampers with θ = 0° and 90° create rectangular-shaped and I-shaped shear links, respectively. The results indicate that the damper with θ = 30° exhibits better performance in terms of ultimate strength, stiffness, overstrength, and distribution stress over the damper as compared to dampers with other angles. The hysteresis curves of the dampers confirm that the proposed damper acts as a ductile fuse. Furthermore, the web and flange plates contribute to the shear resistance, with the flange carrying approximately 80% and 10% of the shear force for dampers with θ = 30° and 90°, respectively. Moreover, dampers that have a larger flange-plate shear strength than the shear strength of the web exhibit behaviours in linear and nonlinear zones. In addition, the over-strength obtained for the damper was greater than 1.5 (proposed by AISC for shear links). Relevant relationships are determined to predict and design the damper and the elements outside it.

• 대한교통학회지
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• 제23권5호
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• pp.135-146
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• 2005

현재까지 다양한 검지기로부터 추정되는 통행시간의 융합에 관한 연구는 주로 GPS, Probe 자료 등 간헐적인 자료에 기반하여 이루어져 왔다. 이러한 간헐적 자료의 분산비에 기초한 융합모형은 번호판 인식 AVI와 같이 다량의 자료 구득이 용이한 시스템에는 적합하지 않다. 따라서, 본 연구는 지점검지기와 번호판 인식 AVI를 기반으로 각각 산출한 통행시간의 융합모형을 개발하고자 수행되었다. 본 연구에서는 지점검지기와 번호판인식 AVI 통행시간의 융합을 위해 최적화 융합모형과 비례화 융합모형을 각각 개발하였다. 검증 결과, 최적화 융합모형이 가장 우수한 추정력을 보여주었다. 최적화 융합모형은 실시간 이력자료를 기반으로 융합 가중치를 산정하여 현재 시간대에 적용하는 실시간 차원의 동적 융합비 예측 모형이다. 본 연구결과는 향후 국도교통관리 및 정보제공시스템에 유용하게 적용될 것으로 기대된다. 그러나, 향후 AVI의 적정설치간격과 설치차로에 따른 매칭율을 고려한 보다 심도있는 연구를 필요로 한다.