• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.44-52
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• 2003

Shape memory alloys (SMA) are often used in smart structures as active components. Their ability to provide large recovery forces and displacements has been useful in many applications, including devices for artificial muscles, active structural acoustic control, and shape control. Based on the 3-dimensional SMA constitutive equation in this paper, the radial displacement control of externally pressurized circular and semicircular composite cylinders under external pressure with a thin SMA layer bonded on its inner surface or inserted between composite layers in investigated using 3-dimensional finite element analysis. Upon actuation through resistive heating, SMAs start to transform from martensitic into austenitic state, simultaneously recover the prestrain, and thus cause the composite cylinders to go back to their original shapes of the cylinder cross-sections.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.35-40
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• 2011

We have studied the impact and bending characteristics of a dual band antenna (1.575, 2.645 GHz) with composite sandwich construction. Mechanical performance of the antenna can be improved by reinforcing the antenna by sandwiching the planar antenna with layers of carbon fiber-reinforced plastic(CFRP) and glass fiber-reinforced plastic(GFRP) using an adhesive film. According to the ASTM D7137, ASTM C393 and MIL-STD401B, impact and bending test were performed and the S-parameters and gains of the antenna were measured in order to verify electrical and mechanical performance. The maximum contact load and the bending load of the antenna are 4 kN and 400 N and gains of the antenna are 6 dBi and 4.6 dBi in the GPS and DMB bands, respectively. The proposed antenna structure can be applied to surfaces of vehicles.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.563-564
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.423-427
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• 1997

Recently, distributed piezoelectric actuators have drawn attention due to their potential applicability within smart structures. Because they serve not only as active components but also passive components, it is difficult to estimate their characteristics accurately. In this study a finite element method based on layerwise theory has been formulated to analyze the characteristics of the distributed piezoelectric actuators. The present method has the capability to describe more refined strain distribution and more realistic boundary conditions.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.423-425
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• 2014

스마트기기의 발달과 보급의 확산과 함께 모바일 인터넷 등 통신서비스 환경이 발전함에 따라 이러닝 환경의 고도화가 진행되면서 유비쿼터스러닝, 모바일러닝을 넘어 스마트 디바이스와 이러닝 연관 신기술이 융 복합된 새로운 형태의 교육 시스템인 스마트러닝으로 발전하고 있다. 하지만 현재 다양한 스마트 디바이스 기반의 스마트러닝 서비스를 통해 교육 콘텐츠를 학습자에게 제공하기 위해서는 기존 이러닝 콘텐츠의 구조 개선이 불가피한 상황이며 콘텐츠의 재사용 가능성, 접근성, 상호운용성, 항구성 및 질적 수월성의 향상을 위한 스마트러닝 표준화가 요구되고 있다. 이에 본 논문에서는 기존 이러닝 콘텐츠를 통한 스마트러닝을 구현하기 위한 방안으로 EPUB 3.0 표준을 활용한 스마트러닝 솔루션을 제안하고자 한다.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.413-421
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• 2016

This research, mainly focused on the development of the iPhone exclusive app 'Sketch Plus', is on the production of pens within the smart media. Our goal is to develop and reproduce pens with surreal rendering as a base and during that process, describe the fusing process of design perspectives and algorithms. This research comprehends the concept of surreal rendering, which is a technique that mimics traditional art forms, and suggests 15 pen techniques and ways to display them by analyzing previous research on smart media. We have described the process of using hatching patterns and resused to solve lag problems that occur during the reproduction of pen techniques due to the limitations of smart devices and organized the conversion process of pen patterns into 4 steps: rough sketch, contrast, applying and mimicking patterns, and applying color. We hope that this research on the reproduction of analog pen techniques can be used as an example for production on fused surreal rendering.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.11-19
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• 2011

A localization development of Composite rotor blade for Smart Unmanned Aerial Vehicle(SUAV) has been conducted. Overall localization development encompassed selection of domestic composite material having similar properties to that of original one at its best, coupon tests for data base of new material properties, re-calculation of blade sectional properties, and validation of structural/dynamic design requirements such as isolation of rotor natural frequency from excitation, static and fatigue strength, aeroelastic stability. The results of all these activities are described. This paper briefly discusses the improved manufacturing process for the localization of SUAV blade.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.121-128
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• 2007

Enhanced lower order shear deformation theory is developed in this study. Generally, lower order theories are not adequate to predict accurate deformation and stress distribution through the thickness of laminated plate. For the accurate prediction of detailed stress and deformation distributions through the thickness, higher order zigzag theories have been proposed. However, in most cases, simplified zigzag higher order theory requires $C_1$, shape functions in finite element implementation. In commercial FE softwares, $C_1$, shape functions are not so common in plate and shell analysis. Thus zigzag theories are useful for the highly accurate prediction of thick composite behaviors but they are not practical in the sense that they cannot be used conveniently in the commercial package. In practice, iso-parametric $C_0$ plate model is the standard model for the analysis and design of composite laminated plates and shells. Thus in the present study, an enhanced lower order shear deformation theory is developed. The proposed theory requires only $C_0$ shape function in FE implementation. The least-squared energy error between the lower order theory and higher order theory is minimized. An enhanced lower order shear deformation theory(ELSDT) in this paper is proposed for smart structure under complex loadings. The ELSDT is constructed by the strain energy transformation and fully coupled mechanical, electric loading cases are studied. In order to obtain accurate prediction, zigzag in-plane displacement and transverse normal deformation are considered in the deformation Held. In the electric behavior, open-circuit condition as well as closed-circuit condition is considered. Through the numerous examples, the accuracy and robustness of present theory are demonstrated.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.704-705
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• 2016

스마트아이 기술은 기존의 재난 감시 및 관리 서비스가 사람에 의한 단순 모니터링 기반의 대응을 제공하는 데 비해, 무인기를 활용해 사람의 사각에서 발생하는 재난 상황을 촬영하여 감시 및 분석을 하며, 무인기에 탑재된 다중 복합 센서 데이터의 실시간 처리 분석을 통해 국지적 산불 재난의 감지 예측 및 상황대응을 지원하고, 통합경보 시스템과 연동하여 대국민 재난 정보 전달 서비스 제공하는 서비스이다. 현재 본 서비스를 제공할 수 있는 Front to End 시스템이 개발 완료되어 실험실 테스트를 진행하였으며, 이와 더불어 실제 필드에서의 재난 감시 및 예측 성능을 검증하기 위한 필드 테스트를 준비 중에 있다. 이에 본 논문에서는 현재 구축하고 있는 스마트아이 재난 관리 플랫폼 실험실 테스트의 진행상황을 간단히 소개하고, 재난 영상의 획득, 분석, 및 예측을 수행하는 통합 플랫폼의 주요 기능들에 대해서 논한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.71-72
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• 2019

최근 공공안전 분야에서는 국민의 위험상황을 분석하여 선제적으로 예측을 하여 국민의 안전을 보장하기 위한 요구사항이 대두대고 있다. 또한 스마트폰 및 스마트워치와 같은 고성능 모바일 단말 기기들의 대중화로 인해 해당 기기들에 부착된 다양한 센서 데이터들을 융복합하여 분석할 경우, 수집한 센서 데이터의 잠재적 가치를 안전보장 측면에서 사용할 수 있는 장점이 있다. 본 논문에서는 대인, 대물, 장소에 해당하는 로그 데이터들을 융복합 분석하여 보호대상자의 안전을 지원하는 다중로그 플랫폼 기반 이동경로 분석 기법을 제안한다. 다중로그 플랫폼에서 수집하는 보호대상자의 이동 경로 궤적을 활용하여 과거에 축적된 이동경로 패턴과 비교를 통해 현재 경로가 평소에 이용하던 경로와의 유사도를 추천하게 된다. 해당 이동 경로 분석 시스템은 위치기반 멀티모달 센서 데이터를 융복합 하여 보호대상자의 안전을 보장하는데 기여 할 것으로 예상된다.