• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권3호
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• pp.316-321
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• 2004

In this paper, we have developed a new mounting head system for flip chip. The proposed head system consists of a macro/micro positioning actuator for stable force control. The macro actuator provides the system with a gross motion while the micro device yields fine tuned motion to reduce the harmful impact force that occurs between very small sized electronic parts and the surface of a PCB(printed circuit board). In order to show the effectiveness of the proposed macro/micro chip mounting system, we compared the proposed system with the conventional chip mounting head equipped with a macro actuator only. A series of experiments were executed under the mounting conditions such as various access velocities and PCB stiffness. As a result of this study, a satisfactory voice coil actuator as the micro actuator has been developed, and its performance meet well the specifications desired for the design of the chip mounting head system and show good correspondence between theoretical analysis and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.716-717
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• 2011

This paper presents the overview of development of substation automation system. The prototypes of SA system are developed in first phase, and being enhanced the performance in second phase. In this research, the project was classified into three projects which are the development of intelligent electronic devices, the development of operation system and communication network in substation, and the development of technology to verify the compatibility of IEC 61850. As a result of this research, the domestic-made SA system are operated and tested for the performance in 154kV substation and/or test-bed in KEPCO PT Center.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.18-20
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• 2005

최근 송배전 시스템 분야에서 종래의 인간의 개입을 최소화하여 이루어질 수 있도록 통합화, 자동화 및 원격 감시화가 추진되고 있으며 이는 기존의 전기 장비들을 통신 기능을 갖는 마이크로 프로세스 기반의 IED(Intelligent Electronic Device)로 대체함으로써 가능해 졌다. 단일 표준화 작업이 이루어지기 전 다양한 프로토콜의 사용에 따른 장비 간 호환성 결여로 통신 프로토콜 표준화 필요성이 강하게 제기되었고, 1990년대 표준화 작업을 시작하여 최근 변전소 자동화용 단일 세계 표준인 IEC 61850이 UCA2.0과 유럽의 경험을 기반으로 IEC주관아래 개발되었다. 이러한 세계기술 동향을 반영해 IEC 61850 기반의 종합변전소 자동화 시스템의 구축이 필요하고, 이에 따라 본 논문에서는 IEC 61850 통신 프로토콜을 살펴보고 기본적인 IED 통신 실험 장치를 구성하고 메시지 전송 실험을 수행하였다.

• ETRI Journal
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• 제37권6호
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• pp.1188-1198
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• 2015

In this paper, a multi-time programmable (MTP) cell based on a $0.18{\mu}m$ bipolar-CMOS-DMOS backbone process that can be written into by using dual pumping voltages - VPP (boosted voltage) and VNN (negative voltage) - is used to design MTP memories without high voltage devices. The used MTP cell consists of a control gate (CG) capacitor, a TG_SENSE transistor, and a select transistor. To reduce the MTP cell size, the tunnel gate (TG) oxide and sense transistor are merged into a single TG_SENSE transistor; only two p-wells are used - one for the TG_SENSE and sense transistors and the other for the CG capacitor; moreover, only one deep n-well is used for the 256-bit MTP cell array. In addition, a three-stage voltage level translator, a VNN charge pump, and a VNN precharge circuit are newly proposed to secure the reliability of 5 V devices. Also, a dual memory structure, which is separated into a designer memory area of $1row{\times}64columns$ and a user memory area of $3rows{\times}64columns$, is newly proposed in this paper.

• 한국재료학회지
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• 제24권11호
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• pp.573-577
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• 2014

The existing metal getters are invariably covered with thin oxide layers in air and the native oxide layer must be dissolved into the getter materials for activation. However, high temperature is needed for the activation, which leads to unavoidable deleterious effects on the devices. Therefore, to improve the device efficiency and gas-adsorption properties of the device, it is essential to synthesize the getter with a method that does not require a thermal activation temperature. In this study, getter material was synthesized using palladium oxide (PdOx) which can adsorb $H_2$ gas. To enhance the efficiency of the hydrogen and moisture absorption, a porous layer with a large specific area was fabricated by an etching process and used as supporting substrates. It was confirmed that the moisture-absorption performance of the $SiO_2/Si$ was characterized by water vapor volume with relative humidity. The gas-adsorption properties occurred in the absence of the activation process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.3-6
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• 2004

반도체 디자인, 공정 기술 및 패기지 기술의 발달에 따라 전력용 반도체는 소형화, 고성능화, 지능화하고 있다. 고속 구동이 용이한 때문에 MOSFET이나 IGBT등의 MOS-gate형 전력 반도체의 발전이 두드려지며, trench, charge balance, NPT 기술등이 패키지 기술과 더불어 이를 위한 주요 기술이 될것으로 보인다. SiC나 GaN등의 Wide Band Gap 물질들을 사용한 차세대 전력 반도체 연구도 활발히 진행되고 있다.

• 한국전기전자재료학회논문지
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• 제27권10호
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• pp.635-641
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• 2014

In this study, the temperature control device was designed for the study in order to detect the output in frequency of temperature, and the study confirmed accurate temperature values treated systemically by using expanded A/D converting Technology. The control technology of functional sensor included the output error Detection. For the future study, it is necessary to implement a control device by building multiple circuits integrally with different types of sensors such as a automatically and intelligent notification function sensors.

• 한국정보통신학회논문지
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• 제17권9호
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• pp.2213-2218
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• 2013

스마트폰, 스마트TV, 태블릿, 게임 콘솔과 같은 스마트 디바이스는 기기가 가진 기본 기능 이외에도 주변의 여러 현상을 인지하고 반응하는 상황인지 컴퓨팅(Context-aware Computing) 기술을 탑재, 이러한 정보를 합성하여 지능적인 애플리케이션 개발을 가능하게 하는 모든 범주의 지능형 통신 기기(Intelligent Communication Device)를 포괄한다. 본 논문에서는 학생안전 네트워크 서비스 시스템에 미리 등록된 학생의 이동경로와 유해업소를 학생용 데이터베이스에 저장한 후, 스마트 디바이스의 위치기반 서비스를 이용하여 학생의 동선을 파악하되 경로를 이탈하는 정도와 유해업소를 출입하거나 우범지역에 머무르는 경우를 파악하고, 학생안전 네트워크 서비스 시스템과 비교분석하여 학생의 안전한 생활지도가 이루어질 수 있도록 방법을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.2972-2991
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• 2016

WLAN is the best choice in the place where complex network is hard to set up. Intelligent terminals are more and more assembled in some areas now. However, according to IEEE 802.11n/802.11ac, the access-point (AP) can only serve one user at a single frequency channel. The spectrum efficiency urgently needs to be improved. In theory, AP with multi-antenna can serve multiple users if these users do not interfere with each other. In this paper, we propose a user clustering scheme that could achieve multi-user selection through the mutual cooperation among users. We focus on two points, one is to achieve multi-user communication with multiple antennas technique at a single frequency channel, and the other one is to use a way of distributed users' collaboration to determine the multi-user selection for user clustering. Firstly, we use the CSMA/CA protocol to select the first user, and then we set this user as a source node using users' cooperation to search other proper users. With the help of the users' broadcast cooperation, we can search and select other appropriate user (while the number of access users is limited by the number of antennas in AP) to access AP with the first user simultaneously. In the network node searching, we propose a maximum degree energy routing searching algorithm, which uses the shortest time and traverses as many users as possible. We carried out the necessary analysis and simulation to prove the feasibility of the scheme. We hope this work may provide a new idea for the solution of the multiple access problem.

• 센서학회지
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• 제32권2호
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• pp.88-94
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• 2023

Recently, piezoelectric tactile sensors have garnered considerable attention in the field of texture recognition owing to their high sensitivity and high-frequency detection capability. Despite their remarkable potential, improving their mechanical flexibility to attach to complex surfaces remains challenging. In this study, we present a flexible piezoelectric sensor that can be bent to an extremely small radius of up to 2.5 mm and still maintain good electrical performance. The proposed sensor was fabricated by controlling the thickness that induces internal stress under external deformation. The fabricated piezoelectric sensor exhibited a high sensitivity of 9.3 nA/kPa ranging from 0 to 10 kPa and a wide frequency range of up to 1 kHz. To demonstrate real-time texture recognition by rubbing the surface of an object with our sensor, nine sets of fabric plates were prepared to reflect their material properties and surface roughness. To extract features of the objects from the detected sensing data, we converted the analog dataset to short-term Fourier transform images. Subsequently, texture recognition was performed using a convolutional neural network with a classification accuracy of 97%.