• 한국융합학회논문지
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• 제11권10호
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• pp.63-69
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• 2020

본 논문에서는 저속으로 불규칙하게 움직이는 인체의 심박신호를 감지하기 할 수 있어 웨어러블 디바이스에 적용 가능한 소형 마이크로파 센서를 제안하였다. 이를 위해 2.4 GHz ISM 대역에서 평형 구조를 갖는 마이크로스트립 방사 패치들과 자체발진 검출회로 및 귀환회로가 구성되었다. 이론 전개와 시뮬레이션을 통해 제안된 구조의 타당성을 확인하였고 제작된 시제품을 측정하였다. 회로의 보드는 65mm × 85㎟의 작은 크기이며, 간단한 고주파 회로구조로 60mW 수준의 작은 전력을 소모한다. 센서와 직선거리 2~30mm, 측면 좌우 거리 ±20mm 범위 내에서 저속(0.5Hz)으로 움직이는 인체로부터 심박신호를 얻을 수 있었다.

• 전기학회논문지
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• 제56권5호
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• pp.990-992
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• 2007

The purpose of this study is to develop a practical gait-event detection system which is necessary for the FES (functional electrical stimulation) control of locomotion in paralyzed patients. The system is comprised of a sensor board and an event recognition algorithm. We focused on the practicality improvement of the system through 1) using accelerometer to get the angle of shank and dispensing with the foot-switches having limitation in indoor or barefoot usage and 2) using a rule-base instead of threshold to determine the heel-off/heel-strike events corresponding the stimulation on/off timing. The sensor signals are transmitted through RF communication and gait-events was detected using the peaks in shank angle. The system could detect two critical gait-events in all five paralyzed patients. The standard deviation of the gait events time from the peaks were smaller when 1.5Hz cutoff frequency was used in the derivation of the shank angle from the acceleration signals.

• International Journal of Internet, Broadcasting and Communication
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• 제12권2호
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• pp.83-89
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• 2020

A microstrip feedline based open ended folded-slot antenna is proposed for ultra-wideband (UWB) applications. The prototype of the proposed antenna is fabricated on the FR4 dielectric substrate. The proposed antenna has a wide n-shaped slot that is useful for designing circuit components on the same printed circuit board (PCB) as that of the radio frequency (RF) modules. The proposed antenna use two kinds of slots as radiators, and each slots have different characteristics because of the different type of ends of the slot. The wideband characteristic can be obtained by resonances of each slot which are occurred at different frequencies. The measured impedance bandwidth (S₁₁≤ -10 dB) is 2.9-11.56 GHz, and the antenna peak gain is 2-4 dBi over the UWB range. The antenna has a stable omni-directional radiation pattern and only a small group-delay variation across the UWB passband. In addition, we present a modified design with band-notched characteristics of a 5 GHz wireless local area network (WLAN) frequency band.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.380-382
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• 2001

This paper presents the implementation of IEEE 802.11 Medium Access Control and Physical Layer Protocol that can be applied to wireless LAN system. We have used PRISM2 chipsets from Intersil to build the baseband, IF, and RF parts. DSSS(Direct Sequence Spread Spectrum) physical layer at 2.4GHz ISM band is adopted in the hardware prototype. To meet the high-speed requirement of physical layer, we have designed the MAC protocol layer with embedded firmware and FPGA. The prototype board is shown to be able to support the physical layer of 5GHz and 600Hz wireless LAN systems.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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• pp.53-58
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• 2003

The Wafer Level Packaging is one of the most important technologies in the semiconductor industry today. Its primary advantages are its small form factor and low cost potential for manufacturing including test procedure. The CASIO's WLP samples, application example and the structure are shown in Fig.1, 2&3. There are dielectric layer , under bump metal, re-distribution layer, copper post , encapsulation material and terminal solder .The key technologies are 'Electroplating thick copper process' and 'Unique wafer encapsulation process'. These are very effective in getting electrical and mechanical advantages of package. (Fig. 4). CASIO and CMK are developing a new System Packaging technology called the Embedded Wafer Level Package (EWLP) together. The active components (semiconductor chip) in the WLP structure are embedded into the Printed Wiring Board during their manufacturing process. This new technical approach has many advantages that can respond to requirements for future mobile products. The unique feature of this EWLP technology is that it doesn't contain any solder interconnection inside. In addition to improved electrical performance, EWLP can enable the improvement of module reliability. (Fig.5) The CASIO's WLP Technology will become the effective solution of 'KGD problem in System Packaging'. (Fig. 6) The EWLP sample shown in Fig.7 including three chips in the WLP form has almost same structure wi_th SoC's. Also, this module technology are suitable for RF and Analog system applications. (Fig. 8)

• 한국생산제조학회지
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• 제22권3_1spc호
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• pp.607-614
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• 2013

This paper proposes a robot driving system and sensor implementation for use with an education robot. This robot has multiple functions and was designed so that children could use it with interest and ease. The robot recognizes the location of a user and follows that user at a specific distance when the robot and user communicate with each other. In this work, the robot was designed and manufactured to evaluate its performance. In addition, an embedded board was installed with the purpose of communicating with a smart phone, and a camera mounted on the robot allowed it to monitor the environment. To allow the robot to follow a moving user, a set of sensors combined with an RF module and ultrasonic sensors were adopted to measure the distance between the user and the robot. With the help of this ultrasonic sensors arrangement, the location of the user couldbe identified in all directions, which allowed the robot to follow the moving user at the desired distance. Experiments were carried out to see how well the user's location could be recognized and to investigate how accurately the robot trackedthe user, which eventually yielded a satisfactory performance.

• 한국표면공학회지
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• 제37권4호
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• pp.220-225
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• 2004

A new ion beam extraction system is designed using a simple ion mass filter and a micro mass balance and a QMS based detecting system. A quadrupole Mass Filter is used for selective ion beam formation from inductively coupled high density plasma sources with appropriate electrostatic lens and final analyzing QMS. Also a quartz crystal microbalance is set between a QMF and a QMS to measure the etching and polymerization rate of the mass selected ion beam. An inductively coupled plasma was used as a ion/radical source which had an electron temperature of 4-8 eV and electron density of $4${\times}$10^{11}$＃/㎤. A computer interfaced system through 12bit AD-DA board can control the pass ion mass of the qmf by setting RF/DC voltage ratio applied to the quadrupoles so that time modulation of pass ion's mass is possible. So the direct measurements of ion - surface chemistry can be possible in a resolution of $1\AA$/sec based on the qcm's sensitivity. A full set of driving software and hardware setting is successfully carried out to get fundamental plasma information of the ICP source and analysed $Ar^{+}$ beam was detected at the $2^{nd}$ QMS.

• 한국전자통신학회논문지
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• 제5권3호
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• pp.288-293
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• 2010

오늘의 정보통신 사회에서는 빠르고 편리함을 추구하여 모든 일을 무선으로 통용하기위해 무선시스템 기술이 끊임없이 성장하고 있다. 이는 바로 광대역화를 기반으로 하는 유비쿼터스(ubiquitous)환경, 즉 언제 어디서나 원격으로 네트워크에 접속하여 이용자들의 편리성을 도모하는 솔루션의 기초가 된다. 본 논문은 전력선 통신과 RFID 모듈을 이용하여 수많은 적용분야들 중에서 도서관리 시스템을 개발한 내용이다. 본 연구는 900 MHz RFID 리더, Passive RFID-Tag, Atmega128 마이크로콘트롤러, 저속 PLC 모뎀 등을 사용함으로써 리더와 서버 PC의 통신과 PC와 Display보드의 통신이 전력선 망을 통해 데이터 전송이 원활이 이루어 졌다.

• 한국인터넷방송통신학회논문지
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• 제21권4호
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• pp.43-49
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• 2021

소형 적외선영상 호밍시스템은 지상의 표적에 대하여 주야간 적외선 영상처리를 통하여 표적을 식별하고 주요 표적에 대하여 표적을 탐색, 탐지하여 추적하는 적외선 영상센서를 보유한 추적시스템이다. 본 논문에서는 지상의 표적을 주야간 적외선 영상을 통하여 표적 정보를 획득하여 실시간 영상처리를 통하여 표적을 식별하기 위한 고속의 CPU와 FPGA(Field Programmable Gate Array)가 탑재된 보드 개발의 내용을 설명한다. CPU, FPGA 선정과 영상신호처리를 위한 CPU-FPGA 결합 아키텍처에 대하여 제안하고 또한 김발구조의 적외선센서를 제어하기 위한 FPGA를 활용에 대하여 설명한다.

• 한국ITS학회 논문지
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• 제7권3호
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• pp.62-73
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• 2008

본 논문에서는 능동방식의 870 nm 적외선 및 5.8 GHz 주파수 통합방식으로 운영되는 고속도로 자동 요금징수 시스템의 능동주파수방식에 대한 국내 표준 개선방안을 제시한 것으로 2007년말 전국에서 운영되고 있다. 본 표준 개선방안은 5.8 GHz 대역의 ITS전용 단거리 무선통신 표준 중 개방형 시스템간 상호접속 참조모델을 기준하여 OSI 1, 2, 7 계층 중 차량단말기와 노변장치간 다중접속을 위한 상호호환성을 제공하는 물리계층을 중심으로 실제 운영중인 시스템 개선방안을 도출하였다. 즉, 기존 표준에서 복사전력의 경우 전송거리에 따라 Class1 (10 m이내)과 Class2 (100 m 이내)로 구분하였으나 Class1 단일규격으로 2004년 정보통신부고시에 의거하여 운영되고 있고, 통신영역내의 입사전력 한계치의 경우 실제 운영중인 자동 요금징수시스템의 운영방안을 고려하여 측정 결과치를 표준에 반영하도록 하였다. 즉, 자동 요금징수 시스템 운영상 필요한 부분에 대해 사업자 시스템간의 호환성 및 안정성을 확보하기 위해서 복사전력, 통신영역에서의 입사전력, 의사응답의 표준개선을 제안하였다.