• 한국융합학회논문지
• /
• 제7권6호
• /
• pp.249-258
• /
• 2016

본 연구는 중소기업의 연구개발 프로세스를 분석하여 국내 중소기업의 연구개발 프로세의 문제점을 진단하고, 혁신역량이 연구개발 속도와 기업 성과에 미치는 영향을 평가했다. 이러한 영향에 대한 평가는 혁신역량에 관한 요인의 융복합요인을 고려하여 분석하는 것으로 유형에 따른 발전방향성을 파악할 수 가 있다. 본 연구의 주요 목적은 혁신역량 및 경영환경에 따라 연구개발 속도에 미치는 영향을 확인하고, 연구의 신뢰성과 유효성 검증을 위해 내부 일관성을 나타내는 크론바흐 알파를 사용하였다. 본 연구는 연구개발 속도가 R&D활동에 어떠한 영향을 미치는지를 분석한 연구이고, 기업의 내부 역량에 관한 자원을 기반한 접근이 필요하다는 것을 목표로 한 연구로 학술적 가치를 갖는다. 각각의 요인에 대해 기업에 미치는 영향에 따라 기업개발역량 수준 유지를 통해 연구개발, 재무적 지표에 미치는 영향을 분석한 연구이며 기업의 전략 수립에 미치는 연구개발 역량 개발에 근거가 될 수 있는 실무적 가치가 있는 연구이다.

• Computers and Concrete
• /
• 제27권5호
• /
• pp.395-406
• /
• 2021

This study experimentally and analytically investigates the shear behavior of corroded reinforced concrete (RC) beams repaired using steel fiber-reinforced concrete (SFRC) in the flexural zone. The experimental parameters are the corrosion degree (0%, 12%, and 17%) and the steel fiber volume in the SFRC (1.0%, 1.5%, and 2.0%). The test results reveal that corrosion degree significantly affects the shear resistance of the beams. The shear capacity of the beam with the corrosion degree of 17% was higher than that of the uncorroded beam, whereas the shear capacity of the beam with the corrosion degree of 12% was lower than that of the uncorroded beam. The shear efficiency of damaged beams can be recovered by repairing them using SFRC that contains a reasonable amount of steel fibers. In addition, two methods to estimate the shear capacity of the repaired beams are developed using the modified truss analogy and strut-and-tie models. The estimated shear capacity of the beam using the modified truss analogy model agrees well with the experimental data.

• Structural Engineering and Mechanics
• /
• 제84권1호
• /
• pp.63-76
• /
• 2022

Major engineering requirements and technological developments in the steel construction industry are discussed to support a new innovative system, namely corrugated web beams, for future structural projections. These new-generation steel beams, fabricated as welded plate girders with corrugated webs, are designed to combine large spans with very low weight. In the present study, the flexural capacity of optimally designed trapezoidal and sinusoidal corrugated web beams was aimed at. For this purpose, the new metaheuristic methods, specifically hunting search and firefly algorithms, were used for the minimum weight design of both beams according to the rules of Eurocode EN 1193 15 and DASt-Ri 015. In addition, the strengthening effects of the corrugation geometry at the web posts on the load capacity of fabricated steel beams were tested in a reaction frame. The experimental tests displayed that the lateral capacity of trapezoidal web beams is more durable under flexural loads compared to sinusoidal web beams. These thin-walled beams were also simulated using a 3-D finite element model with plane strain to validate test results and describe the effectiveness of the ABAQUS software.

• Computers and Concrete
• /
• 제17권1호
• /
• pp.67-86
• /
• 2016

Strengthening as well as correcting unsightly deflections of reinforced concrete (RC) beam may be accomplished by retrofitting. An innovative way to do this retrofitting that is proposed in this study utilizes turnbuckle to apply external post-tensioning. This Turnbuckle External Post-Tensioning (T-EPT) was experimentally proven to improve the serviceability and load carrying capacity of reinforced concrete beams. The T-EPT system comprises a braced steel frame and a turnbuckle mechanism to provide the prestressing force. To further develop the T-EPT, this research aims to develop a numerical scheme to analyze the structural performance of reinforced concrete beams with this kind of retrofitting. The fiber method analysis was used as the numerical scheme. The fiber method is a simplified finite element method that is used in this study to predict the elastic and inelastic behavior of a reinforced concrete beam. With this, parametric study was conducted so that the effective setup of doing the T-EPT retrofitting may be determined. Different T-EPT configurations were investigated and their effectiveness evaluated. Overall, the T-EPT was effective in improving the serviceability condition and load carrying capacity of reinforced concrete beam.

• Journal of Electrochemical Science and Technology
• /
• 제7권3호
• /
• pp.206-213
• /
• 2016

Transition metal oxide-based electrodes for lithium ion batteries have recently attracted much attention because of their high theoretical capacity. Here we report the electrochemical behavior of cobalt oxide nanorods as anodes, prepared by a template-free, one-step electrochemical deposition of cobalt nanorods, followed by an oxidation process. The as-deposited cobalt has a slightly convex columnar structure, and controlled thermal oxidation produces cobalt oxides of different Co/O ratios, while the original shape is largely preserved. As an anode in a rechargeable lithium battery, the Co/O ratio has a strong effect on initial capacity and cycling stability. In particular, the one-dimensional Co@Co_xO_y core shell structure obtained from a mild heat-treatment results in superior cycling stability.

• Geomechanics and Engineering
• /
• 제29권2호
• /
• pp.171-182
• /
• 2022

Reusing the used pile has not yet been implemented due to the unpredictability of the bearing capacity evolution. This paper presents an analytic approach to estimate the sides shear setup after the dissipation of pore pressure. Long-term evolution of adjacent soil is simulated by viscoelastic-plastic constitutive model. Then, an innovative concept of quasi-overconsolidation is proposed to estimate the strength changes of surrounding soil. Total stress method (α method) is employed to evaluate the long term bearing capacity. Measured data of test piles in Louisiana and semi-logarithmic time function are cited to validate the effectiveness of the presented method. Comparisons illustrate that the presented approach gives a reasonably prediction of the side shear setup. Both the presented method and experiment show the shaft resistance increase by 30%-50%, and this highlight the potential benefit of piles reutilization.

• Computers and Concrete
• /
• 제33권6호
• /
• pp.739-754
• /
• 2024

This study presents an innovative AI-driven approach to assess the ultimate axial load in Double-Skinned Profiled Steel sheet Composite Walls (DPSCWs). Utilizing a dataset of 80 entries, seven input parameters were employed, and various AI techniques, including Linear Regression, Polynomial Regression, Support Vector Regression, Decision Tree Regression, Decision Tree with AdaBoost Regression, Random Forest Regression, Gradient Boost Regression Tree, Elastic Net Regression, Ridge Regression, and LASSO Regression, were evaluated. Decision Tree Regression and Random Forest Regression emerged as the most accurate models. The top three performing models were integrated into a hybrid approach, excelling in accurately estimating DPSCWs' ultimate axial load. This adaptable hybrid model outperforms traditional methods, reducing errors in complex scenarios. The validated Artificial Neural Network (ANN) model showcases less than 1% error, enhancing reliability. Correlation analysis highlights robust predictions, emphasizing the importance of steel sheet thickness. The study contributes insights for predicting DPSCW strength in civil engineering, suggesting optimization and database expansion. The research advances precise load capacity estimation, empowering engineers to enhance construction safety and explore further machine learning applications in structural engineering.

• 한국융합학회논문지
• /
• 제8권1호
• /
• pp.203-212
• /
• 2017

불확실한 환경 하에서 국가 발전과 산업기반 조성에 중추적인 역할을 할 수 있는 세계적인 수준의 기술역량 확보는 필수적이다. R&D 탁월성에 기반을 둔 기술역량 강화를 목적으로 국가R&D시스템의 중요한 R&D주체인 출연(연)을 대상으로 우수기술 혹은 우수조직 현황을 살펴보는 탐색연구를 실시하였다. 출연(연) 사례를 관통하는 개념으로 세계 최고의 기술 확보를 들 수 있으며, 세계 최고에 대한 측정기준은 분야 특성상 다를 수 있으나 해당분야에서 최고의 기술역량을 확보하고자 하는 노력은 글로벌 선도기술, 기관중점과제, 세계적 혁신기술, World Class Laboratory 제도, 글로벌 수월성 연구그룹 등의 사례에서 일관되게 관찰된다. R&D주체들의 기술역량 강화를 위해 해당분야에서 탁월한 기술성과 창출이 가능하도록 조직의 기술역량 발굴이 지속적으로 필요하며, 기술역량 발굴노력을 연구사업, 신성장동력 발굴 등의 형태로 구체화 시키고, 세계 최고임을 인정하는 조직 내부의 공감대 형성이 중요하다.

• 기술혁신학회지
• /
• 제21권1호
• /
• pp.354-384
• /
• 2018

본 연구는 사회적 자본의 관점에서 혁신중개인과 기업과의 관계가 흡수역량에 어떠한 영향을 미치는지 분석한다. 그리고 기업의 혁신환경요인은 이 과정에서 직 간접적으로 흡수역량에 어떠한 영향을 미치는지에 대해 연구한다. 이를 위해 국내 대표적인 혁신클러스터인 대덕연구개발특구 내 입주하고 있는 200여개 기업을 대상으로 실증분석을 수행함으로써 제시한 연구질문을 검증하고자 한다. 주요 연구결과는 기업이 활용하고 있는 혁신중개인의 관계와 혁신환경요인이 흡수역량과의 관계에서 전반적으로 유의한 정(+)의 효과가 있음을 보여준다. 세부적으로 혁신중개인의 관계 중에서 신뢰도 및 소통빈도는 흡수역량에 유의한 영향을 미치며, 반면에 지리적 근접성에 대해서는 유의하지 않은 것으로 분석되었다. 또한, 혁신중개인이 기업의 흡수역량에 미치는 영향에서 기업이 직면하고 있는 혁신환경요인은 정(+)의 조절역할을 하며, 하위차원에서는 사회적 요인이 뚜렷하고 긍정적인 영향을 미친다는 사실을 조명하고 있다. 본 연구는 기업의 기술혁신과정에서 혁신중개인의 역할과 흡수역량의 선행요인으로서의 혁신중개인의 중요성과 더불어 혁신환경요인의 중요성 대한 이해에 기여한다.

• Structural Engineering and Mechanics
• /
• 제73권3호
• /
• pp.239-257
• /
• 2020

In the present study, an innovative steel bracket and haunch hybrid scheme is devised, for retrofitting of earthquake damaged deficient beam-column sub-assemblages. Formulations are presented for evaluating haunch force factor under combined load case of lateral and gravity loads for the design of double haunch retrofit. The strength hierarchies of control and retrofitted beam-column sub-assemblages are established to showcase the efficacy of the retrofit in reversing the undesirable strength hierarchy. Further, the efficacy of the proposed retrofit scheme is demonstrated through experimental investigations carried out on gravity load designed (GLD), non-ductile and ductile detailed beam-column sub-assemblages which were damaged under reverse cyclic loading. The maximum load carried by repaired and retrofitted GLD specimen in positive and negative cycle is 12% and 28% respectively higher than that of the control GLD specimen. Further, the retrofitted GLD specimen sustained load up to drift ratio of 5.88% compared with 2.94% drift sustained by control GLD specimen. Repaired and retrofitted non-ductile specimen, could attain the displacement ductility of three during positive cycle of loading and showed improved ductility well above the expected displacement ductility of three during negative cycle. The hybrid haunch retrofit restored the load carrying capacity of damaged ductile specimen to the original level of control specimen and improved the ductility closer to the expected displacement ductility of five. The total cumulative energy dissipated by repaired and retrofitted GLD, non-ductile and ductile specimens are respectively 6.5 times, 2.31 times, 1.21 times that of the corresponding undamaged control specimens. Further, the damage indices of the repaired and retrofitted specimens are found to be lower than that of the corresponding control specimens. The novel and innovative steel bracket and haunch hybrid retrofit scheme proposed in the present study demonstrated its effectiveness by attaining the required displacement ductility and load carrying capacity and would be an excellent candidate for post-earthquake retrofit of damaged existing RC structures designed according to different design evolutions.