• Structural Engineering and Mechanics
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• 제68권5호
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• pp.563-573
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• 2018

Temperature-induced responses, such as strains and displacements, are related to the boundary conditions. Therefore, it is required to determine the boundary conditions to establish a reliable bridge model for temperature-induced responses analysis. Particularly, bridge bearings usually present nonlinear behavior with an increase in load, and the nonlinear boundary conditions cause significant effect on temperature-induced responses. In this paper, the bridge nonlinear boundary conditions were simulated as bilinear translational or rotational springs, and the boundary parameters of the bilinear springs were identified based on the measured temperature-induced responses. First of all, the temperature-induced responses of a simply support beam with nonlinear translational and rotational springs subjected to various temperature loads were analyzed. The simulated temperature-induced strains and displacements were assumed as measured data. To identify the nonlinear translational and rotational boundary parameters of the bridge, the objective function based on the temperature-induced responses is then created, and the nonlinear boundary parameters were further identified by using the nonlinear least squares optimization algorithm. Then, a beam structure with nonlinear translational and rotational springs was simulated as a numerical example, and the nonlinear boundary parameters were identified based on the proposed method. The numerical results show that the proposed method can effectively identify the parameters of the nonlinear boundary conditions. Finally, the boundary parameters of a real arch bridge were identified based on the measured strain data and the proposed method. Since the bearings of the real bridge do not perform nonlinear behavior, only the linear boundary parameters of the bridge model were identified. Based on the bridge model and the identified boundary conditions, the temperature-induced strains were recalculated to compare with the measured strain data. The recalculated temperature-induced strains are in a good agreement with the real measured data.

• 기술혁신학회지
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• 제21권4호
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• pp.1536-1576
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• 2018

본 연구는 기업가지향성과 흡수역량이 중소기업의 성과에 미치는 영향을 제품혁신성과의 매개효과를 중심으로 분석한다. 구조방정식 모델을 활용하여 중소기업의 기업성과에 중요한 영향을 미치는 기업가지향성과 흡수역량이 제품혁신성과(제품속도, 제품품질)를 매개로 성과에 이르는 경로를 규명한다. 실증연구를 위해 대전테크노파크 입주기업 등 총 1,775개 중소기업을 대상으로 설문조사를 시행하여 수집한 설문지 233부의 응답 내용을 구조방정식 모형을 활용하여 분석하였다. 실증분석결과 흡수역량과 기업가지향성이 제품혁신성과를 매개로 성과에 긍정적 영향을 주는 것으로 나타났다. 기업가지향성과 흡수역량이 높을수록 제품속도와 제품품질을 높이고 제품혁신성과가 기업의 성과로 연결되고 있음을 알 수 있다. 따라서 기업의 전략 측면과 외부 정보 활용 역량 측면에서 기업가지향성과 흡수역량이 제품혁신성과를 높이고, 제품혁신성과가 기업의 성과로 이어진다고 볼 수 있다. 이러한 분석결과는 외부환경에 대응하여 우수한 품질의 제품을 더 빠르게 창출하여 성과를 높이는 데 기업의 전략과 외부 정보를 흡수 활용하는 흡수역량이 중요함을 시사하고 있다.

• 한국해양공학회지
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• 제33권5호
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• pp.486-494
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• 2019

Recently, the interest in marine leisure activities has been growing rapidly with the work-life balance trend. In response to this demand, the Korean government is supporting fostering and revitalizing the relevant industries and facilities. In particular, a marina has been making efforts to change itself into a resort with multiple amenities instead of a simple mooring facility. However, the facilities in a marina for the transport of marine leisure equipment mostly consist of cranes and boat-lifts using ropes, which can result in incidents such as damage and accidents during lifting or movement. This paper proposes the equipment and support system for the safe transportation of marine leisure ships. Aluminum transport equipment was designed by performing a structural analysis to achieve a lighter weight than the existing steel products. In addition, a safety support system with alarms for tilting or obstacles and a slope monitoring system was developed to enhance the safety during operation and transportation. The safety support system developed in this study was implemented and installed in the transport system, and verified through commissioning on land.

• 한국컴퓨터정보학회논문지
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• 제26권3호
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• pp.137-142
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• 2021

본 연구의 목적은 유튜브 이용의 주요한 동기 요인인 인지된 유용성과 인지된 즐거움이 강박적 유튜브 사용 및 대학생의 학업 적응에 미치는 영향을 알아보는데 있다. 이 목적을 달성하기 위한 연구 모형을 설정하고 서울 지역의 대학생을 대상으로 설문조사를 실시하여 얻은 113건의 응답 자료를 최종 분석에 활용하였다. 실증 분석 결과는 첫째, 인지된 유용성은 학업 적응에 긍정적인 영향을 미치는 것으로 나타났다. 둘째, 강박적 유튜브 사용이 높을수록 학업 적응은 낮은 것으로 확인되었다. 셋째, 인지된 즐거움은 학업 적응에 긍정적인 영향을 주는 동시에 강박적 유튜브 사용을 높이는 파르마콘과 같은 역할을 하는 요인으로 확인되었다. 본 연구 결과는 대학생의 학업 적응을 높이기 위해 유용성의 도구적 이용뿐만 아니라 인지된 즐거움의 정도를 조절하는 학습 전략의 필요성을 시사하고 있다.

• 한국의류산업학회지
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• 제23권2호
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• pp.200-211
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• 2021

This study examines the effects of fashion influencers' body types (realistic versus ideal body types) on self-expression, self-representation, and recommendation intentions, as mediated by familiarity toward influencers. Although fashion influencers lead to a positive consumer response compared to traditional advertisements, previous research on the effects of fashion influencers on consumers is limited. Thus, this study tests the role of consumers' socio-psychological aspects in understanding how and why fashion influencers affect consumers' behavioral intentions associated with self-expression, self-representation, and influencer recommendation. A total of 180 women in their 20s and 30s participated in the survey. The responses were collected after showing them stimuli featuring fashion influencers with either ideal or realistic body shapes. The data were analyzed using SPSS18.0 for descriptive statistics, and AMOS 18.0 for confirmatory factor analysis and structural equation modeling. The results showed that participants who were shown realistic body types perceived familiarity, which generated positive effects on self-expression, self-representation, and recommendation intentions. Hence, the effects of influencers' body types on recommendation intention are mediated by familiarity. Self-expression and self-representation intentions also increase influencer recommendation intention. Comparatively, participants who were shown ideal body types only induced higher self-representation intention, which increased their recommendation intention. The current findings can help fashion marketers select the appropriate influencers who fit their target customers as promotional models, as well as to induce changes in consumers' behavioral intention.

• Advances in concrete construction
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• 제13권5호
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• pp.385-394
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• 2022

Recently, an increasing number of cutting-edged studies have shown that designing a smart active control for real-time implementation requires piles of hard-work criteria in the design process, including performance controllers to reduce the tracking errors and tolerance to external interference and measure system disturbed perturbations. This article proposes an effective artificial-intelligence method using these rigorous criteria, which can be translated into general control plants for the management of civil engineering installations. To facilitate the calculation, an efficient solution process based on linear matrix (LMI) inequality has been introduced to verify the relevance of the proposed method, and extensive simulators have been carried out for the numerical constructive model in the seismic stimulation of the active rigidity. Additionally, a fuzzy model of the neural network based system (NN) is developed using an interconnected method for LDI (linear differential) representation determined for arbitrary dynamics. This expression is constructed with a nonlinear sector which converts the nonlinear model into a multiple linear deformation of the linear model and a new state sufficient to guarantee the asymptomatic stability of the Lyapunov function of the linear matrix inequality. In the control design, we incorporated H Infinity optimized development algorithm and performance analysis stability. Finally, there is a numerical practical example with simulations to show the results. The implication results in the RMS response with as well as without tuned mass damper (TMD) of the benchmark building under the external excitation, the El-Centro Earthquake, in which it also showed the simulation using evolved bat algorithmic LMI fuzzy controllers in term of RMS in acceleration and displacement of the building.

• Steel and Composite Structures
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• 제41권5호
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• pp.663-679
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• 2021

To elucidate the differences in the collapse behavior between a single-story beam-column assembly and multi-story frame, two 1/3-scale two-bay composite frames, including a single-story composite beam-column assembly and a three-story composite sub-frame, were designed and quasi-statically tested. The load-displacement responses, failure modes, and internal force development of the two frames were analyzed and compared in detail. Furthermore, the resistance mechanisms of the two specimens were explored, and the respective contributions of different load-resisting mechanisms to the total resistances were quantitatively separated to gain deeper insights. The experimental tests indicated that Vierendeel action was present in the two-dimensional multi-story frames, which led to an uneven internal force distribution among the three stories. The collapse resistance of TSDWA-3S in the flexural stage was not significantly increased by the structural redundancy provided by the additional story, as compared to that of TSDWA-1S. Although the development of the load response was similar in the two specimens at flexural stage, the collapse mechanisms of the multi-story composite frame were much more complicated than those of the single-story beam-column assembly, and the combined action between stories was critical in determining the internal force redistribution and rebalancing of the remaining structure.

• Structural Engineering and Mechanics
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• 제83권4호
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• pp.551-561
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• 2022

In this paper, the effect of fire conditions according to ISO 834 standard on the behavior of carbon fibre-reinforced plastic (CFRP) reinforced steel beams coated with gypsum-based mortar has been investigated numerically. To study the efficiency of these beams, 3D coupled temperature-displacement finite element analyzes have been conducted. Mechanical and thermal characteristics of three different parts of composite beams, i.e., steel, CFRP plate, and fireproof coating, were considered as a function of temperature. The interaction between steel and CFRP plate has been simulated employing the adhesion model. The effect of temperature, CFRP plate reinforcement, and the fireproof coating thickness on the deformation of the beams have been analyzed. The results showed that within the first 120 min of fire exposure, increasing the thickness of the fireproof coating from 1 mm to 10 mm reduced the maximum temperature of the outer surface of the steel beam from 380℃ to 270℃. This increase in the thickness of the fireproof layer decreased the rate of growth in the temperature of the steel beam by approximately 30%. Besides excellent thermal resistance and gypsum-based mortar, the studied fireproof coating method could provide better fire resistance for steel structures and thus can be applied to building materials.

• 문화기술의 융합
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• 제7권4호
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• pp.291-297
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• 2021

현재의 공식적이고 암기식인 공예디자인 반복 훈련과 실습은 획일적인 평면적 디자인사고 표현에서 방황하고 있다. 이러한 평면적 현안 문제를 입체적 디자인 방식으로 변경하려면 통합된 융복합 교육목표 아래에서 학년별 방향을 설정하고 단계적으로 프로젝트를 수행하여 공예디자인에 대한 이해, 공간구성의 원리, 전통 디자인역사의 도입, 공예디자인의 총체적 접근 등 창작과 실무능력을 배양하여야 한다. 공예디자이너는 체계적인 교육과 훈련을 통해서만이 배출될 수 있다. 이는 다양한 시대변화의 요구에 대하여 스스로를 어떻게 적응해 나갈지에 대한 해결능력과 대처방안을 경험한 디자이너가 현장에 나와야 사회를 리드하고 성공할 수 있다. 교육 전문가들은 교육제도의 조직구조와 교과목의 혁신을 주장하며, 변화의 속도가 더욱 빠르게 진행될 21세기에 대응하는 교육의 중요성을 역설하였다. 본 연구는 이러한 문제에 대한 이해 및 분석을 통해 디자인과 인접학문이 연계된 융복합실습을 사회의 니즈를 반영한 프로젝트를 설정하여 과제를 구조적 접근에 의한 학문적 연구가 병행하는 교육체계를 제안하고자 한다.

• Structural Engineering and Mechanics
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• 제86권3호
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• pp.385-397
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• 2023

This study presents an experiment and analysis to compare the seismic behavior of full-scale reinforced concrete beam-column joint strengthened by prestressed steel strips, externally bonded steel plate, and CFRP sheets. For experimental investigation, five specimens, including one joint without any retrofitting, one joint retrofitted by externally bonded steel plate, one joint retrofitted by CFRP sheets, and two joints retrofitted by prestressed steel strips, were tested under cyclic-reserve loading. The failure mode, strain response, shear deformation, hysteresis behavior, energy dissipation capacity, stiffness degradation and damage indexes of all specimens were analyzed according to experimental study. It was found that prestressed steel strips, steel plate and CFRP sheets improved shear resistance, energy dissipation capacity, stiffness degradation behavior and reduced the shear deformation of the joint core area, as well as changed the failure pattern of the specimen, which led to the failure mode changed from the combination of flexural failure of beams and shear failure of joints core to the flexural failure of beams. In addition, the beam-column joint retrofitted by steel plate exhibited a high bearing capacity, energy consumption capacity and low damage index compared with the joint strengthened by prestressed steel strip, and the prestressed steel strips reinforced joint showed a high strength, energy dissipation capacity and low shear deformation, stirrups strains and damage index compared to the CFRP reinforced joint, which indicated that the frame joints strengthened with steel plate exhibited the most excellent seismic behavior, followed by the prestressed steel strips.