• 디지털융복합연구
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• 제16권5호
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• pp.435-443
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• 2018

본 연구의 목적은 형태초점교수법이 학습자의 언어형태에 관한 지식 향상에 미치는 영향을 조사하고, 학습자들이 그 형태에 관한 지식을 출력활동인 글쓰기에 어떻게 활용하는지를 살펴보는 것이다. 연구참여자들은 122명의 대학생들로 3개의 집단 즉 입력강화집단 35명, 출력강화집단 41명, 대조집단 46명으로 나누어 평가시험과 글쓰기 과제를 사전 사후로 실시하였다. 연구결과를 살펴보면, 입력강화 형태초점교수법과 출력강화 형태초점교수법 모두 학습자의 언어형태 학습에 영향을 미치는 것으로 드러났고, 학습자들이 이러한 형태초점교수법으로 습득한 지식을 영어글쓰기에 활용하는데 기여한 것으로 나타났다. 본 연구결과에 의거하여, 학습자의 언어형태 학습의 효과를 극대화할 수 있는 방법으로 입력강화와 출력강화기법을 적절하게 결합한 형태초점교수법을 적용할 것을 제안한다.

• Structural Engineering and Mechanics
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• 제67권6호
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• pp.555-563
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• 2018

Architectural fabrics membranes have not only the structural performance but also act as an efficient cladding to cover large areas. Because of the direct relationship between form and force distribution in tension membrane structures, form-finding procedure is an important issue. Ideally, once the optimal form is found, a uniform pre-stressing is applied to the fabric which takes the form of a minimal surface. The force density method is one of the most efficient computational form-finding techniques to solve the initial equilibrium equations. In this method, the force density ratios of the borders to the membrane is the main parameter for shape-finding. In fact, the shape is evolved and improved with the help of the stress state that is combined with the desired boundary conditions. This paper is evaluated the optimum amount of this ratio considering the curvature of the flexible boarders for structural configurations, i.e., hypar and conic membranes. Results of this study can be used (in the absence of the guidelines) for the fast and optimal design of fabric structures.

• 한국전산구조공학회논문집
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• 제27권4호
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• pp.313-320
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• 2014

텐세그리티 구조물은 인장력을 받는 연속된 케이블 안에 압축력을 받는 스트럿이 결합된 형태로 구성된다. 텐세그리티 구조물은 자기 응력 상태를 갖는 프리스트레스 핀 접합 구조물에 속한다. 텐세그리티 구조물 설계의 핵심은 평형 배열상태를 구하는 일명 형상탐색 과정이다. 본 논문에서는 세 가지의 효과적인 텐세그리티 구조물의 형상탐색 기법을 제안하였다. 형상탐색과정을 수행하면 평형상태의 내력 밀도와 그에 대응하는 위상을 얻을 수 있다. 이 때 평형상태를 형성하는 적절한 내력밀도 값을 얻기 위해 유전자 알고리즘을 결합한 내력밀도법이 사용되었다. 수치해석 예제를 통해 제안 알고리즘의 효율성을 입증하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.41-44
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• 1999

Nonlinear sliding surface design in variable structure systems for spacecraft attitude control problems is studied. A robustness analysis is performed for regular form of system, and calculation of actuator bandwidth is presented by reviewing sliding surface dynamics. To achieve non-singular attitude description and minimal parameterization, spacecraft attitude control problems are considered based on modified Rodrigues parameters(MRP). It is shown that the derived controller ensures the sliding motion in pre-determined region irrespective of unmodeled effects and disturbances.

• 복합신소재구조학회 논문집
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• 제5권2호
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• pp.1-8
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• 2014

Fiber reinforced polymeric plastic (FRP) materials have many advantages over conventional structural materials, i.e., high specific strength and stiffness, high corrosion resistance, right weight, etc. Among the various manufacturing methods, pultrusion process is one of the best choices for the mass production of structural plastic members. Since the major reinforcing fibers are placed along the axial direction of the member, this material is usually considered as an orthotropic material. However, pultruded FRP (PFRP) structural members have low modulus of elasticity and are composed of orthotropic thin plate components the members are prone to buckle. Therefore, stability is an important issue in the design of the pultruded FRP structural members. Many researchers have conducted related studies to publish the design method of FRP structures and recently, referred to the previous researches, pre-standard for LRFD of pultruded FRP structures is presented. In this paper, the accuracy and suitability of design equation for the local buckling strength of pultruded FRP I-shape compression members presented by ASCE are estimated. In the estimation, we compared the results obtained by design equation, closed-form solution, and experiments conducted by previous researches.

• 한국분말재료학회지
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• 제26권6호
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• pp.528-538
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• 2019

The transition from "More-of-Less" markets (economies of scale) to "Less-of-More" markets (economies of scope) is supported by advances of disruptive manufacturing and reconfigurable-supply-chain management technologies. With the prevalence of cyber-physical manufacturing systems, additive manufacturing technology is of great impact on industry, the economy, and society. Traditionally, backbone structures are built via bottom-up manufacturing with either pre-fabricated building blocks such as bricks or with layer-by-layer concrete casting such as climbing form-work casting. In both cases, the design selection is limited by form-work design and cost. Accordingly, the tool-less building of architecture with high design freedom is attractive. In the present study, we review the technological trends of additive manufacturing for construction-scale additive manufacturing in particular. The rapid tooling of patterns or molds and rapid manufacturing of construction parts or whole structures is extensively explored through uncertainties from technology. The future regulation still has drawbacks in the adoption of additive manufacturing in construction industries.

• 대한건축학회논문집:구조계
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• 제35권7호
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• pp.171-178
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• 2019

Auto Climbing Formwork System (ACS) for construction of high-rise building is a construction method for automatically lifting the formwork system supported by the anchor on the pre-constructed concrete wall. It has excellent construction speed and quality, but it has the possibility of structural failure depending on the quality of concrete and also has low economical efficiency due to the use of foreign technology. In order to overcome these problems, this study conducted an optimum design for the development of a new concept of Corner Supported Auto Climbing System (CS-ACS) in conjunction with the development of corner steel-reinforced concrete core wall system. For the design the formwork system, the basic module and structural member compositions were planned, and the structural analysis program was used to analyze the optimum member's cross section and spacing. As a result, the horizontal displacement and the stress of the horizontal members were influenced by the spacing more than the cross-section of the member. On the other hand, vertical members did not affect the displacement and stress of the formwork system. The form tie was very effective in controlling the displacement when adjusting the spacing of the horizontal members, but when the spacing of the form tie is more than 1,500mm, it is analyzed that form tie is yielding in basic module. When the span of the formwork system is more than 30m, it is analyzed that the basic module needs to be changed because of the increase of overall displacement.

• Wind and Structures
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• 제29권5호
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• pp.339-359
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• 2019

Pre-stressed concrete poles are among the supporting systems used to support transmission lines. It is essential to protect transmission line systems from harsh environmental attacks such as downburst wind events. Typically, these poles are designed to resist synoptic wind loading as current codes do not address high wind events in the form of downbursts. In the current study, the behavior of guyed pre-stressed concrete Transmission lines is studied under downburst loads. To the best of the authors' knowledge, this study is the first investigation to assess the behaviour of guyed pre-stressed concrete poles under downburst events. Due to the localized nature of those events, identifying the critical locations and parameters leading to peak forces on the poles is a challenging task. To overcome this challenge, an in-house built numerical model is developed incorporating the following: (1) a three-dimensional downburst wind field previously developed and validated using computational fluid dynamics simulations; (2) a computationally efficient analytical technique previously developed and validated to predict the non-linear behaviour of the conductors including the effects of the pretension force, sagging, insulator's stiffness and the non-uniform distribution of wind loads, and (3) a non-linear finite element model utilized to simulate the structural behaviour of the guyed pre-stressed concrete pole considering material nonlinearity. A parametric study is conducted by varying the downbursts locations relative to the guyed pole while considering three different span values. The results of this parametric study are utilized to identify critical downburst configurations leading to peak straining actions on the pole and the guys. This is followed by comparing the obtained critical load cases to new load cases proposed to ASCE-74 loading committee. A non-linear failure analysis is then conducted for the three considered guyed pre-stressed concrete transmission line systems to determine the downburst jet velocity at which the pole systems fail.

• 한국정보전자통신기술학회논문지
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• 제2권2호
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• pp.79-85
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• 2009

이 연구는 인터넷 웹에서의 참 뜻을 바로 소통될 수 있도록 가시적인 시각구조에 협력 학습의 형태로 진화 되어질 Mashup Web의 디지털 멀티미디어 표현기술(記述)을 연구하고, 그 설계와 구현을 하였다. 이 기술은 작성된 웹에 접한 사용자의 접속위치정보, 서비스이용 형식(pattern)을 학습 받는 시스템으로 추적(Tracking)되는 기능이 요구자에 새로운 정보로 탐색과 습득할 수 있도록 추론 정보를 선 처리(pre-operation) 받을 수 있게 하는 Mashup 정보표현기술이다.

• 한국콘텐츠학회논문지
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• 제13권8호
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• pp.474-481
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• 2013

본 연구는 지속적인 창의 인성교육을 위한 수업설계모형을 구안하기 위하여 NFTM-TRIZ를 활용하는데 그 목적을 두었다. NFTM-TRIZ는 TRIZ에 기반하여 유아에서 성인에 이르기까지 '지속적인 창의성 교육'을 할 수 있도록 개발된 교육프로그램이다. TRIZ는 주어진 문제의 모순을 찾아내고 이를 극복함으로써 혁신적인 해결안을 얻도록 하는 창의적 문제해결방법론으로 알려져 있다. 본 연구의 과정은 G 대학교의 교직과목으로 개설된 "교육과정 및 교육평가"를 수강한 3, 4학년 남, 여 학생들 80명을 대상으로 매주 10분 내지 15분씩 창의성 수업을 한 후, 이에 대한 산출물로 NFTM-TRIZ의 8단계 교수 학습 절차에 맞추어 각자의 전공 교과별로 창의 인성 교육을 위한 수업안을 만들어 제출토록 하고 창의성 수업에 대한 후기를 작성토록 하여 연구 결과를 분석했다.