• 항공우주시스템공학회지
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• 제14권4호
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• pp.40-46
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• 2020

Recently, the aviation industry has sought to reduce its carbon usage in aircraft operations. Specifically, the industry is proceeding with the development of ultra-large turbofan engines and the development of hybrid electric engines to reduce the fuel consumption of aircraft. In one case, Airbus is developing as its future goal an aircraft with a short take-off distance that uses a catapult. In this study, when a b747-400 aircraft with two of the four engines removed was tested using a catapult, its fuel consumption was compared with that of the original aircraft. Fuel consumption was calculated using the mass flow consumption formula. Further, the aircraft L/D ratio caused by engine removal was interpreted using the CFD Tool, Ansys Fluent. The results showed that the lift ratio was improved by about 7% and that the fuel efficiency was improved by about 14%.

• 품질경영학회지
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• 제35권1호
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• pp.113-123
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• 2007

This paper considers the development of e-learning training program for the six sigma green belt. Comparative studies of existing e-learning programs are performed and a new one is proposed. A catapult simulator is developed and the automatic grading function which immediately computes the result of the catapult simulation and gives feedback to the trainees is presented. An illustrative example is also given.

• 로봇학회논문지
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• 제8권2호
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• pp.136-142
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• 2013

In nature, many small insects are using jumping as a survival strategy. Among them, fleas jump in a unique method. They use an elastomer, 'Resilin', an extensor muscle and a trigger muscle. By contracting the extensor muscle, the elastic energy, that makes a flea to jump, is stored in the resilin. After storing energy, the trigger muscle begins contracting and pulling the extensor muscle. When the extensor muscle crosses the rotational joint, direction of torque generated from the extensor muscle reverses, 'torque reversal mechanism'. Simultaneously, the elastic energy stored in the resilin releases rapidly and is converted into the kinetic energy. It makes a flea to jump 150 times its body length. In this paper, miniaturized jumping robot using flea-inspired catapult mechanism is presented. This mechanism is based on the 4-bar linkage and the reversal joint and is actuated by Shape Memory Alloy (SMA) coiled springs describing the flea's muscle. The robot prototype is fabricated by SCM process using glass fiber prepregs and a sheet of polyimide film. The prototype is 20mm link length, 34mm width and 2.0g weight and can jump 103cm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.968-973
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• 1991

Seven axis modular type pneumatic manipulator is composed of electro-pneumatic automation system which contributes to factory automation by performing loading & unloading process successively which is simple routine work of dealing item of machine tool, catapult, assembly machine, welding machine and so on. In this study, we obtained soft and quick movement in a large space and good reliability motion of various function by combining several actuators which perform rotation movement as well as linear movement at the same time. Gripper which apply to rotary sensor transmitted a structure to demanded position. This development item of 5kgf load prevent stick-slip phenomena of stroke end by designing high cushion internal. We develope flexible manipulator which conforms to demand of user by applying multiple sequence program.

• Design & Manufacturing
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• 제2권2호
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• pp.6-9
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• 2008

Injection molding is representative process of plastic production. Most of numerical analyses for injection molding have been based on the Hele Shaw's approximation: two-dimensional flow analysis. The present work covers numerical analyses of injection molding using three-dimensional solid elements. The accuracy of the analysis results has been verified through some numerical examples in comparison with the various conditions. In this study, moldflow software was used to analyze the cooling analysis. The results of cooling analysis and testing catapult were compared for plastic products.

• 공학교육연구
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• 제11권1호
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• pp.64-75
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• 2008

신제품의 개발 및 제품실현화 과정은 창의적 문제해결과정을 통한 아이디어를 창출하고 피드백과 순환적인 과정을 통해서 이를 발전시키고 보완해 나가는 과정이다. 이러한 제품실현화 과정의 초기 단계인 개념설계와 제품개발의 단계가 절약가능한 비용요소의 대부분을 차지하며 이 단계의 최적 설계를 위한 방안으로 다구치가 제안한 강건설계 방법이 효과적이다. 품질은 검사를 통해서가 아니고 공학적 접근을 통해 향상될 수 있다. 강건설계는 제품의 연구개발 단계에 있어서 행해지는 공학적 방법론으로서 제품의 품질에 영향을 미치는 변화자체를 제거하지는 않고 변화에 의한 효과를 최소화함으로써 품질을 향상시키고 최적 디자인 파라미터를 얻고자 하는 것이다. 본 연구의 목적은 강건설계 방법을 이용하여 제품개발단계에서 효과적인 설계 파라미터를 탐색하는 방법을 소개하고, 이를 공학교육의 창의성 개발과 관련하여 적용해 보는 사례를 소개하고자 하는 것이다. 주된 연구내용은 창의적 문제해결과정과 강건설계의 파라미터 선정 과정을 제시하고, 강건설계 방법을 창의성 교육에 활용하는 과정 및 이에 따른 실습내용이다. 강건설계의 실습을 위해서 투석기를 이용하였고, 실험한 투석기와 유사한 기능을 수행 할 수 있는 장비를 창의적 접근방법으로 디자인 하도록 하였다. 또한 레퍼런스 모델을 제시하여 아이디어를 비교평가 하게 함으로써 창의적 문제해결의 반복 순환적 과정을 체험하게 하였다.

• 패션비즈니스
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• 제20권2호
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• pp.32-45
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• 2016

Outdoor wear, which is typically worn for outdoor activities, has become a style that is worn on a daily basis, much like ordinary clothes, through recent megatrends. There are new approaches to outdoor wear with high-fashion brands and designers recently taking part in the trend. This indicates that outdoor wear has already reached high-fashion, no longer making it just a megatrend or daily fashion. Therefore this study aims to find new features of outdoor looks and designs, through the latest women's ready-to-wear collections from 2014 to 2015. The study will focus on mega collections, which have shown many new approaches, and searches to change and development the present day outdoor look design, by using the word 'outdoor look' which is explained as a 'style' in a broad sense, and using it a general term of 'clothes'. High fashion brands have pursued changing their styles by mixing their designs with outdoor wear's variety, functionality and details; attempting new approaches and challenges. Due to these updated changes, the outdoor look is thriving and becoming part of high fashion. Looking forward to future new approaches and the development of the outdoor look will help catapult this type of 'style' into a new category of modern fashion.

• Archives of Plastic Surgery
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• 제50권4호
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• pp.415-421
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• 2023

The revision of the Korea Organ Transplantation Act (KOTA) in 2018 included hand/arm among the organs that can be transplanted. The first hand transplantation since the revision of KOTA took place in January 2021. A 62-year-old male patient experienced hand amputation on July 13, 2018, by a catapult injury. The patient first visited our institute 3 months after the injury. After serial interviews and an overall evaluation, the patient was registered on the hand transplantation waiting list in January 2020. On January 9, 2021, the patient underwent hand transplantation at the right distal forearm level. The total operation time was 17 hours 15 minutes, and the cold ischemic time was 4 hours 9 minutes. Postoperative immunosuppression was administered based on the protocol used for kidney transplantation. Two acute rejection episodes occurred, on postoperative days 33 and 41. Both rejection episodes were reversible with rescue therapy of a higher tacrolimus trough level, steroid pulse therapy, and topical immunosuppressants. Controlled passive range of motion exercise was started on postoperative day 10. Dynamic splint was applied on postoperative day 18. At 1 year, graft maintenance and functional improvement were satisfactory, and the patient showed a Disabilities of Arm, Shoulder and Hand score of 25.8. We successfully performed the first hand transplantation surgery under the KOTA amendment. It came from the organic and effective cooperation of plastic, orthopaedic, and transplantation departments and we believe it will guarantee the future ongoing success.