• Steel and Composite Structures
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• 제19권2호
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• pp.417-439
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• 2015

Many methods are developed for strengthening of reinforced concrete structural members against the effects of shear. One of the commonly used methods in recent years is turned out to be bonding of fiber reinforced polymers (FRP). Impact loading is one of the important external effects on the reinforced concrete structural members during service period among the others. The determination of magnitude, the excitation time, deformations and stress due to impact loadings are complicated and rarely known. In recent year impact behavior of reinforced concrete members have been researched with experimental studies by using drop-weight method and numerical simulations are done by using finite element method. However the studies on the strengthening of structural members against impact loading are very seldom in the literature. For this reason, in this study impact behavior of shear deficient reinforced concrete beams that are strengthened with carbon fiber reinforced polymers (CFRP) strips are investigated experimentally. Compressive strength of concrete, CFRP strips spacing and impact velocities are taken as the variables in this experimental study. The acceleration due to impact loading is measured from the specimens, while velocities and displacements are calculated from these measured accelerations. RC beams are modeled with ANSYS software. Experimental result and simulations result are compared. Experimental result showed that impact behaviors of shear deficient RC beams are positively affected from the strengthening with CFRP strip. The decrease in the spacing of CFRP strips reduced the acceleration, velocity and displacement values measured from the test specimens.

• 한국전자통신학회논문지
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• 제8권6호
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• pp.923-931
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• 2013

RFID(Radio Frequency Identification)는 버스카드, 출입문 카드, 물류유통, 건축자재 관리 등 일상생활에서 다양하게 사용되는 태그의 일종으로 ID정보를 무선 주파수(RF, Radio Frequency)를 사용하여 인식하는 무선인식장치이다. RFID는 투과성과 인식률, 메모리 크기, 다중태그 인식률, 외부 오염 먼지, 외부 충격 등에 따라 크기와 성능이 달라지고, 이와 같은 요소들을 고려한 RFID 보호를 위한 패키징이 필요하다. 현재 RFID는 건축자재의 효과적인 관리를 위해서도 다양하게 사용되고 있는데, 건축자재에 RFID를 부착하기 위해서는 외부로 부터의 충격에 강건한 건축자재용 RFID 패키징 제작이 요구되고 있다. 본 논문에서는 외부 충격에 강하고, 고장 시 RFID의 교체가 가능하도록 패키징 틀과 본체를 분리하여 설계된 건축자재용 RFID 패키징을 제안한다. 제안된 RFID 패키징을 위한 상세한 설계도를 제시하였으며, 3D 프린터를 사용하여 설계된 패키징을 직접 제작하여 성능 평가를 실시하였다.

• 산업경영시스템학회지
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• 제43권1호
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• pp.42-49
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• 2020

This study is an empirical research to find out the effect on the management performance of hidden champions of food manufacturing companies when using blue ocean strategy for new product development. In order to achieve the purpose of this study, we conducted a questionnaire survey on hidden champions in the domestic food manufacturing industry and proceeded empirical analysis. When small and medium-sized enterprises in food manufacturing industries develop a new product, searching for non-customer, rebuilding the market boundary, and linking the external networks have a significant impact on their management performance. However, the fair procedure did not have a significant effect on the management performance. In terms of relative influence, rebuilding the market boundary was most affecting, followed by searching for non-customer and linking the external networks. On the other hand, this study implicated the management performance of hidden champions of food manufacturing industries when new products is developed by using the blue ocean strategy. Obtained results are as follows. If small and medium-sized enterprises of food manufacturing industries develop new products, it will be able to improve the management performance by utilizing strategies such as searching for non-customer, rebuilding the market boundary, and linking the external networks. In particular, the rebuilding the market boundary among the blue ocean strategies has a relatively high impact on management performance.

• Current Photovoltaic Research
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• 제11권4호
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• pp.134-143
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• 2023

Efforts are being made to respond to global warming. Interest in and demand for the private sector-led RE100 campaign is also increasing. Self-built solar power generation, one of the implementation tools for RE100, is not expanding. However, it can be an economical means of implementation in the long run. In this study, we intend to analyze the impact on the optimal ratio of self-solar power generation using HOMER simulation. OPR defines the optimal solar power generation ratio and looks into what changes there are in the optimal solar power ratio when self-power consumption increases and external power purchase price changes. As a result, the optimal rate of self-solar power generation has a low impact even if self-power consumption increases. As the external power unit price increases, the optimal ratio increases, and at a power unit price of 100 KRW/kWh, OPR is 24%; at 200 KRW/kWh OPR is 31%; and at 300 KRW/kWh OPR is 34%. This shows that the electricity price replaced during the life cycle has a high impact on the economic feasibility of solar power generation. However, when the external power unit price reached a certain level, the increase in OPR decreased. This shows that it is difficult for domestic companies to achieve RE100 based on the economic feasibility of solar energy alone. Therefore, efforts are needed to supply renewable energy in the public sector.

• 한국안전학회지
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• 제30권3호
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• pp.7-12
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• 2015

CFRP composites are used as primary structural members in various industrial fields because their specific strength and specific stiffness are excellent in comparison to conventional metals. Their usage is expanding to high added-value industrial fields because they are more than 50% lighter than metals, and have excellent heat resistance and wear resistance. However, when CFRP composites suffer impact damage, destruction of fiber and interface delamination occur. This causes an unexpected deterioration of strength, and for this reason it is very difficult to ensure the reliability of the excellent mechanical properties. Therefore, for the destruction mechanism in bending with impact damage, this study investigated the reinforcement data regarding various external loads by identifying the consequential strength deterioration. Specimens were damaged by impact with a steel ball propelled by air pressure. Decrease in bending strength caused by the tension and compression of the impact side, and depending on the lamination direction of fiber and interface inside the specimen. From the bending test it was found that the bending strength reduced when the impact energy increased. Especially in the case of compression on the impact side, as tensile stress occurred at the damage starting point, causing rapid failure and a substantially reduced failure strength.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.84.2-84
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• 2002

$\textbullet$ The dynamic model of a floating human body is derived $\textbullet$ Introduction to impact model for human body $\textbullet$ Analysis of external impulse on the sole $\textbullet$ Analysis of internal impulse at the joints $\textbullet$ It is shown through simulation that the internal impulses for two different configurations

• Composites Research
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• 제27권4호
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• pp.141-145
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• 2014

본 논문은 충격 센서로써 압전 페인트 센서를 사용해 구조물 건전성 모니터링을 수행하였다. 본 연구에 적용된 압전 페인트는 페인트 형태의 압전 재료로 물체에 얇게 코팅할 수 있고, 추가적인 외부 전원 필요 없이 충격 센서로 사용할 수 있다는 장점을 지닌다. 본 논문에서는 복합재 시편에 압전 페인트 센서를 네 부분으로 구분하여 도포한 후 충격 실험을 수행하였다. 압전 페인트 센서의 감도는 충격 힘에 따른 출력 전압을 측정하여 구하였고, 감도 측정과 더불어, 시편에 충격이 가해진 경우 압전 페인트 센서의 출력 신호를 비교하여 충격 위치도 추정하였다.

• 한국가시화정보학회지
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• 제13권1호
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• pp.49-53
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• 2015

Recently, researches for droplet impact phenomena have been faced a new phase in the direction of studying the effect of complex external conditions (e.g. wettability, temperature, morphology, electric field, etc.) for depth understanding and precise controlling in various applications. Hence, here we investigated the electrified droplet impact phenomena, because there were few quantitative researches for electrified droplet impact when we considering many real applications such as electrospray, electrohydrodynamic (EHD) jet printing. To observe interaction effect of surface charge between substrate and droplet simultaneously, micro-droplets with various Reynolds number (Re) and Weber number (We) were dripped on super-hydrophobic surface with existence and nonexistence of electrical surface charge. It shows three kinds of impact behaviors, fully bouncing, partial bouncing, and splashing with different We. Also, charged droplet bounced higher on electrically charged surface than on non-charged surface. Additionally, transition regions of three impact behaviors were classified quantitatively with water hammer pressure value, which means instant pressure inside droplet at the impact moment.

• 소음진동
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• 제5권1호
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• pp.95-106
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• 1995

Flow-induced vibration in heat exchanger (or fuel rod) in nuclar power plant can cause dynamic interactions between tubes and tube supports resulting in fretting-wear. To increase the reliability and design life of heat exchanger components, design criteria that establish acceptable limits of vibration and minimize fretting wear are necessary. The fretting-wear rate is dependent upon material combination, contact configuration, environmental conditions and tube-to tube support dynamic interaction. It is demostrated that the fretting -wear rate correlates well with tube-to-support contact force or work rate. The tube-to-support dynamic interaction, which consists of dynamic contact forces and tube motion, is used to relate single-span wear data to real heat exchanger configurations consisting of multi-span tube bundles. This paper describes the test facility to measure tube-to-support dynamic impact force and reports its dynamic characteristics through the four impact tests - a force transduces independent and external impact tests, central ring inside impact test and additional cylinder impact test. Through the tests the impact parameter change dependent upon the material difference of impacting ball is studied, and the impact parameters of Force Transducer Assembly components are measured. And also the dynamic behavior of Force Transducer Assembly is analyzed. The force measurement technique herein is shown to provide a reasonable measure of dynamic contact forces.

• Nuclear Engineering and Technology
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• 제46권4호
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• pp.529-540
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• 2014

In this research, a drop impact analysis of a fuel assembly in a research reactor is carried out to determine whether the fuel plate integrity is maintained in a drop accident. A fuel assembly drop accident is classified based on where the accident occurs, i.e., inside or outside the reactor, since each occasion results in a different impact load on the fuel assembly. An analysis procedure suitable for each drop situation is systematically established. For an accident occurring outside the reactor, the direct impact of a fuel assembly on the pool bottom is analyzed using implicit and explicit approaches. The effects of the key parameters, such as the impact velocity and structural damping ratios, are also studied. For an accident occurring inside the reactor, the falling fuel assembly may first hit the fixing bar at the upper part of the standing fuel assembly. To confirm the fuel plate integrity, a fracture of the fixing bar should be investigated, since the fixing bar plays a role in protecting the fuel plate from the external impact force. Through such an analysis, the suitability of an impact analysis procedure associated with the drop situation in the research reactor is shown.