• Journal of KIISE:Software and Applications
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• v.32 no.4
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• pp.258-267
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• 2005

We propose the ubiFloor system to track and recognize users in ubiquitous computing environments such as ubiHome. Conventional user identification systems require users to carry tag sensors or use camera-based sensors to be very susceptible to environmental noise. Though floor-type systems may relieve these problems, high cost of load cell and DAQ boards makes the systems expensive. We propose the transparent user identification system, ubiFloor, exploiting user's walking pattern to recognize the user with a set of simple ON/OFF switch sensors. The experimental results show that the proposed system can recognize the 10 enrolled users at the correct recognition rate of $90\%$ without users' awareness of the system.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.157-168
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• 2009

In this paper, a photovoltaic system is designed with a step up chopper and single phase PWM(Pulse Width Modulation) voltage source inverter. Where proposed Synchronous signal and control signal was processed by one-chip microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical voltage and current dropping character. The single phase PWM voltage source the inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power. from 10 to 20[%]. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In order to enhance the efficiency of photovoltaic cells, photovoltaic positioning system using sensor and microprocessor was design so that the fixed type of photovoltaic cells and photovoltaic positioning system were compared. In result, photovoltaic positioning system can improved 5% than fixed type of photovoltaic cells. In addition, I connected extra power to the system through operating the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and the phase of single-phase inverter of PWM voltage type can be synchronized. And, It controlled in order to provide stable pier to the load and the system through maintaining high lurer factor and low output power of harmonics.

• Journal of the HCI Society of Korea
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• v.10 no.2
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• pp.65-71
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• 2015

In this paper, we present binocular augmented reality system with smartphones. With improvements of performance and resolution of recent smartphones, various virtual reality devices using smartphones and applications are appearing in the market. But the augmented reality system with smartphones are not that popular because of the lack of required technologies. In our work, we discuss about 3D mapping and tracking using computer vision. Also, we provide hybrid tracking using sensors in the smartphone which can handle the computer vision failure cases. Bare hand 3D interaction method in our system will be also presented.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1614-1619
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• 2003

In this study, position and force simultaneous trajectory tracking control system with pneumatic cylinder driving apparatus is proposed. The pneumatic cylinder driving apparatus that consists of two pneumatic cylinders constrained in series and two proportional flow control valves offers a considerable advantage as to non-interaction of the actuators because of the low stiffness of the pneumatic cylinders. The controller applied to the driving system is composed of a non-interaction controller to compensate for interaction of two cylinders and a disturbance observer to reduce the effect of model discrepancy of the driving system in the low frequency range that cannot be suppressed by the non-interaction controller. The experimental results with the proposed control system show that the interacting effects of two cylinders are eliminated remarkably and the proposed control system tracks the given position and force trajectories accurately.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.509-512
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• 2009

최근 차량용 IT 기술이 발달함에 따라 네비게이션, 위치추적, 인터넷 접수, 원격 차량 진단, 사고감지, 긴급구난, 교통정보 등을 제공하는 서비스들이 등장하고 있다. 또한 차량의 편의성과 안정성을 추구함과 동시에 친환경 등에 대한 요구도 증가하고 있다. 그리고 최근 차량 상호간 정보의 교환이 더욱 필요해짐에 따라 차량간의 무선 통신 기능이 중요해지고 있으며 차량 내의 네트워크 기술에 대한 연구도 필요하다. 현재 차량 내 네트워크로는 CAN, LIN, MOST등의 유선으로 된 버스 시스템을 중심으로 한 차량 제어 시스템과 멀티미디어 시스템으로 크게 구분할 수 있다. 그러나 자동차 내에 장치 배선이 복잡해짐에 따라 차량의 무게 증가, 고장율의 증가, 연비 저하 등으로 이어지고 있다. 이러한 문제를 보완하기 위해 차량 내에 무선 센서 네트워크 시스템과의 통합 개발이 요구되고 있다. 본 논문에서는 빠르게 발전하고 있는 차량 내 네트워크에 대한 기술개발 동향을 분석하고, 유무선 통합형 차량 내 네트워크 응용 서비스들을 제시하고자 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.153-159
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• 2009

In this paper, we deal with the coordinate estimate algorithm of the wired tablet device. In order to got the position of the electric pen on the tablet, electromagnetic induction effect is used. Most electric tablets have used the electromagnetic induction effect. Tracking the position of the pen on a tablet that is directly related with the performance of the device is very important. In this research, a new real time coordinate estimate algorithm is introduced. To estimate the position of the pen, the electromagnetic induced signals og the wired tablet are used.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1819-1822
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• 2003

자바카드는 스마트카드와 같은 작은 메모리를 가진 임베디드 장치를 위한 프로그램으로 국제 표준인 ISO-7816 과 산업 표준인 EMV 와 호환되며 IMT-2000 보안 표준화를 진행하고 있다. 그러나, 기존 3GPP의 인증 및 키 일치 프로토콜에는 해킹에 대한 취약성이 존재한다. 그래서 본 논문에서는 표준 3GPP(보안 SMS), 자바카드 기술과 규격(보안 APDV) 그리고 암호화 기술 등을 사용하여 기존 3GPP 보안메커니즘의 취약성을 방지 및 극복할 수 있는 자바카드 기반 IMT-2000 보안 프로토콜에 대하여 연구하였다. 이 기술은 무선상거래, 무선 보안, 전자지불시스템, 모바일 인터넷, 위치추적 서비스 그리고 유비쿼터스 컴퓨팅 환경 등에 널리 사용 될 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.188-191
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• 2019

최근 노인인구가 증가하고, 독거노인의 비율도 빠르게 증가하는 추세에 있다. 따라서 몸에 갑작스러운 이상 증상이 발현되거나 건강상 위험 상태에 이르는 경우 따로 돌보는 사람이 없더라도 이를 인지하고 보호받을 수 있는 기기나 장비가 필요하다. 본 논문은 사람의 생체 신호를 이용하여 응급상황을 판단하고, 이를 신속히 지인 또는 다른 사람에게 알리는 응급상황 알림 시스템 설계에 관한 내용이다. 본 시스템은 체온과 심박수를 실시간으로 측정하는 센서들과 실시간 위치추적이 가능한 GPS장치, 측정 데이터를 전송 및 저장하는 데이터 서버 및 사용자의 스마트폰에 설치될 밴드 전용 어플리케이션으로 구성된다. 이를 통해 독거노인뿐만 아니라 모든 1인 가구를 대상으로 갑작스러운 신체 이상증상 발생 시에도 신속히 대처가 가능한 기기 및 장비로서 널리 사용된다면 보건 품질의 향상이 기대된다.

• Journal of Drive and Control
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• v.17 no.4
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• pp.8-14
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• 2020

Intelligent devices using ICT technology have been introduced in the field of construction machinery to improve productivity and stability. Among the intelligent devices, Machine Guidance is a device that provides real-time posture, location, and work range to drivers by installing various sensors, controllers, and satellite navigation systems on construction machines. Conversely, the efficiency of equipment that requires location information, such as machine guidance, will be greatly reduced in buildings, and tunnels in the GPS blind spots. Thus, the other high-precision positioning technologies are required in the GPS blind spot zone. In this study, we will develop a relative position measurement system that provides precise location information such as construction machinery and robots in a local area where the GPS reception is difficult. A relative position measurement system tracks a marker in the form of a sphere installed on a vehicle by using the image base tracking technology, and measures the distance and direction information to the marker to calculate a position.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.155-160
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• 2003

This paper presents a multiple face detector based on a robust pupil detection technique. The pupil detector uses active illumination that exploits the retro-reflectivity property of eyes to facilitate detection. The detection range of this method is appropriate for interactive desktop and kiosk applications. Once the location of the pupil candidates are computed, the candidates are filtered and grouped into pairs that correspond to faces using heuristic rules. To demonstrate the robustness of the face detection technique, a dual mode face tracker was developed, which is initialized with the most salient detected face. Recursive estimators are used to guarantee the stability of the process and combine the measurements from the multi-face detector and a feature correlation tracker. The estimated position of the face is used to control a pan-tilt servo mechanism in real-time, that moves the camera to keep the tracked face always centered in the image.