• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.176.2-176.2
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• 2014

In this work, we demonstrated that the fabrication of flexible graphene-based chemical sensor with heaters by soft lithographic patterning method [1]. First, monolayer and multilayer graphene were prepared by thermal chemical vapor deposition transferred onto SiO2 / Si substrate in order to fabrication of patterned-sensor and -heater. Second, patterned-monolayer and multilayer graphene were detached through soft lithography process, which was transferred on top and bottom sides of PET film. Third, Au / Ti (Thickness : 100/30 nm) electrodes were deposited end of the patterned-graphene line by sputtering system. Finally, we measured sensor properties through injection of NO2 and CO2 gas on different temperature with voltage change of graphene heater.

• 한국지능시스템학회논문지
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• 제20권6호
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• pp.799-805
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• 2010

본 논문은 사용자의 운행 정보를 이용하여 사용자의 선호도 및 성향과 주변의 환경을 판단하고 적용하여 사용자에게 적합한 경로를 추천하는 지능형 네비게이션 시스템을 제안한다. 이 네비게이션 시스템은 센서 정보와 지능형교통시스템의 정보를 이용하여 추천된 경로의 환경 상태와 지형상태를 평가하고 사용자의 감정 상태와 사용자에게 심리적인 영향을 주는 도로의 환경 상태도 고려한다. 또한 소프트 컴퓨팅 기법을 사용하여 인간의 선호도와 성향을 추론 및 학습하며 제안한 알고리즘은 시뮬레이션을 통해 검증한다.

• 마이크로전자및패키징학회지
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• 제25권4호
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• pp.25-34
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• 2018

In this paper, we review the latest technical progress and commercialization of stretchable interconnectors, stretchable strain sensors, and stretchable substrates for stretchable electronics. The development of stretchable electronics can pave a way for new applications such as wearable devices, bio-integrated devices, healthcare and monitoring, and soft robotics. The essential components of stretchable electronic devices are stretchable interconnector and stretchable substrate. Stretchable interconnector should have high stretchability and high electrical conductivity as well as stability under severe mechanical deformation. Therefore several nanocomposite-based materials using CNT, graphene, nanowire, and metal flake have been developed. Geometric engineering such as wavy, serpentine, buckled and mesh structure has been well developed. Stretchable substrate should also pose high stretchability and compatibility with stretchable sensing or interconnecting material. We summarize the recent research results of new materials for stretchable interconnector and substrate as well as strain sensors. The Important challenges in development of the stretchable interconnector and substrate are also briefly discussed.

• 한국가스학회지
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• 제2권3호
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• pp.49-53
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• 1998

온라인 가스 크로마토그래피와 같은 실시간 분석기기는 데이터 채취 및 분석과정의 시간이 오래 걸려 측정 신뢰성이 낮으며 또한 설치 및 보수비용이 많이 들어서, 실제 가스 산업 공정에서는 온도, 압력과 같은 공정의 운전 변수들을 이용하여 간접적으로 가스의 성분 및 양을 감지하는 소프트 센서에 관한 연구가 활발하게 진행 중이다. 본 연구에서는 데이터 기반 소프트 센서의 설계에 있어서 공정 데이터가 갖는 패턴을 잘 반영하여 추정 능력을 높이는 내적 조합모델 PLS를 제안하고, 이를 산업체의 농도 추정 목적으로 적용하였다. 제안된 PLS모델은 기존에 제시된 모델들보다 뛰어난 추정 능력을 보였다.

• 대한임베디드공학회논문지
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• 제4권3호
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• pp.112-117
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• 2009

An animal assisted therapy (AAT) for handicapped child's psychotherapy has been reported by some researches. A robot can be substituted for the role of a real animal of the AAT. The robot for the AAT is called RAT (Robot Assisted Therapy). It consists of four parts: microprocessor-based MCU(Micro Control Unit), sensing part with various sensors, the movement part operated by some motors, and the exterior with soft feel. We will here introduce the RAT.

• 청정기술
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• 제22권3호
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• pp.203-207
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• 2016

Here, we report a novel fabrication technique for patchable organic lasing sheet based on non-volatile liquid organic semiconductors and freestanding polymeric film with high flexibility and patchability. For this work, we have fabricated the second-order DFB grating structure, which leads to surface emission, embedded in the freestanding polymeric film. Using an ultra-violet (UV) curable polyurethaneacrylate (PUA) mixture, the periodic DFB grating structure can be easily prepared on the freestanding polymeric film via a simple UV curing process. Due to unsaturated acrylate remained in the PUA mixture after UV curing, the freestanding PUA film provides adhesive properties, which enable mounting of the patchable organic lasing sheet onto non-flat surfaces with conformal contact. To achieve laser actions in the freestanding resonator structure, a composite material of liquid 9-(2-ethylhexyl)carbazole (EHCz) and organic laser dyes was used as the laser medium. Since the degraded active materials can be easily refreshed by a simple injection of the liquid composite, such a non-volatile liquid organic semiconducting medium has degradation-free and recyclable characteristics in addition to other strong advantages including tunable optoelectronic responses, solvent-free processing, and ultimate mechanical flexibility and uniformity. Lasing properties of the patchable organic lasing sheet were also investigated after mounting onto non-flat surfaces, showing a mechanical tunability of laser emission under variable surface curvature. It is anticipated that these results will be applied to the development of various patchable optoelectronic applications for light-emitting displays, sensors and data communications.

• 한국IT서비스학회지
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• 제19권3호
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• pp.139-149
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• 2020

There are now many different commercial weather sensors suitable for smart farms, and various smart farm devices are being developed and distributed by companies participating in the government-led smart farm expansion project. However, most do not comply with standard specifications and are therefore limited to use in smart farms. This paper proposed the connecting structure of operating non-standard node devices in smart farms following standard specifications supporting smart greenhouse. This connecting structure was proposed as both a virtual node module method and a virtual node wrapper method. In addition, the SoftFarm2.0 system was experimentally operated to analyze the performance of the implementation of the two methods. SoftFarm2.0 system complies with the standard specifications and supports non-standard smart farm devices. According to the analysis results, both methods do not significantly affect performance in the operation of the smart farm. Therefore, it would be good to select and implement the method suitable for each non-standard smart farm device considering environmental constraints such as power, space, distance of communication between the gateway and the node of the smart farm, and software openness. This will greatly contribute to the spread of smart farms by maximizing deployment cost savings.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1166-1168
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• 2003

In most power electronic applications, the AC power input provided by the electronic utility needs to first converted to a DC voltage. Such conversion is accomplished by a diode rectifier due to its circuit simplicity and low cost. However, since diode rectifiers have some intrinsic problems such as low power factor and high harmonic distortion, a wide use of such rectifiers may cause noises, malfunction and heat damage in both electrical power systems and electrical machinery systems. This paper proposes soft switched three-phase single switch boost-type converter. The proposed circuit can perform Zero Voltage Switched(ZVS) without using any current and voltage sensors. For this circuit, both simulation and experiments have been performed. The results not only confirmed the ZVS but also indicated that, compared to the conventional hard switched converter, the prosed circuit can improve the efficiency as much as 1.7 to 4.7[%] while keeping the same high power factor and small harmonic distortion in their AC input.

• 센서학회지
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• 제22권5호
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• pp.352-356
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• 2013

We developed a novel fabrication method of polydimethylsioxane (PDMS) lens, which can easily control the shapes of the lens using soft lithography with common photolithography and water droplet molding. A mold for PDMS lens was prepared by patterning of hydrophobic photoresist on the hydrophilic substrate and dispensing small water droplets onto the predefined hydrophilic patterns. The size of patterns determined the dimension of the lens and the dispensed volume of the water droplet decided the radius of curvature of the PDMS lens independently. The water droplet with photoresist pattern played a robustly fixed mold for lens due to difference in wettability. The radius of curvature could be calculated theoretically because the water droplets could approximate spherical cap on the substrate. Finally, concave and convex PDMS lenses which could reduce or magnify optically were fabricated by curing of PDMS on the prepared mold. The measured radii of the fabricated PDMS lenses were well matched with the estimated values. We believe that our simple and efficient fabrication method can be adopted to PDMS microlens and extended to micro optical device, lab on a chip, and sensor technology.

• 한국지능시스템학회논문지
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• 제17권2호
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• pp.190-195
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• 2007

유비쿼터스 시대가 다가오면서 앞으로 가정 및 회사 등 인간이 거주하며 생활하는 공간에서의 좀 더 편리하고 효율적인 다양한 정보를 인지시켜 줄 수 있는 환경이 구축되어야 한다. 이를 기반으로 유비쿼터스 주변 장치들의 네트워크는 인간에게 많은 정보와 편리성이 좀 더 효율적으로 이루어져야 할 것이다. 이를 위해 본 논문에서는 센서모듈에서 추출되는 데이터를 신경망과 퍼지 알고리즘을 사용해 동작인식의 패턴을 분류하여 인간행동의 사고를 파악한다. 이러한 패턴의 분류를 통해 홈 네트워크 시스템과의 센서모듈의 통신제어가 가능하게 된다. 이를 바탕으로 패턴이 분류된 행동들의 명령으로 여러 가전기기라든지 홈 네트워크 시스템의 제어방식을 더욱 간단히 제어하며, 인간의 건강상태를 파악함으로써 인간행동과 상태에 따른 유비쿼터스 환경의 제어가 이루어 질 수 있는 시스템을 제안한다.