• Electronics and Telecommunications Trends
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• v.31 no.2
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• pp.95-106
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• 2016

사물인터넷(Internet of Things: IoT)이란 모든 사물이 인터넷에 연결되어 상호 간에 직접 통신하는, 향후 정보통신의 미래 인프라 및 서비스이다. 이것이 필요한 이유는 초연결 사회에 기반을 둔 삶의 질 향상과 생산성 향상에 있으며, 최종적으로는 국가 자체의 인프라, 더 나아가서는 인류를 위한 중추 신경계를 이루기 때문에 무엇보다 중요하다. IoT는 셀룰러 이동통신 기반의 IoT와 비셀룰러기반의 IoT로 대분되어 오다가 두 분야의 융합이 이루어지고 있다. 그러나 IoT는 현재 거품 최고조기에 있으며, 아직까지 주목할 만한 큰 수익모델이 없는 상태이다. 그 이유는 사물인터넷 서비스 활성화에 가장 걸림돌이 되어온 보안문제, 배터리수명, 통신거리, IoT 디바이스를 포함한 솔루션 가격 그리고 월정료 문제가 여전히 존재하기 때문이다. 최근 이들 문제 해결을 목적으로, 대량의 IoT 디바이스를 필요로 하는 새로운 사물인터넷 커넥티비티에 대한 재정의, 표준화 및 솔루션 개발이 핫이슈이다. 본고에서는 셀룰라 및 비셀룰라 IoT기반의 Low Power Wide Area(LPWA), 즉 저전력 광역 IoT에 대한 시장, 기술 및 솔루션 비교 그리고 표준화 동향을 다룬다. 또한, 비셀룰라기반 즉 비면허대역과 프리밴드 활용을 통한 기술적 및 정책적 대응전략을 살펴본다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.60-66
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• 2008

The operating voltage of Li/SOCl2 battery decrease immediately when we give a load battery stored for long time. It is called voltage delay. We cannot rapidly operate equipment at emergence situation because the voltage delays. So we have to overcome voltage delay. We reported the results improved voltage delay in this paper through the control of the carbon cathode forming density. It is the classic method in order to control of voltage delay that is coating polymer in the lithium surface or put in the additive to electrolyte. If the carbon cathode forming density decreases, the operating voltage of battery becomes to increasing because solution resistance of battery reduce.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1505-1506
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• 2011

염료감응형 태양전지(Dye-Sensitized Solar Cell, DSSC)의 FTO 표면에 compact layer를 형성시켜 직접적인 마찰에 의한 전자의 재결합을 줄일 수 있다. 따라서 광전극에서의 compact layer의 효과를 최대화하기 위하여 $TiCl_4$ 용액에 acetic acid를 첨가하여 특성변화를 측정하였다. UV-Vis 분광기, I-V 특성곡선, EIS 분석장비를 이용하여 검토한 결과, UV-Vis 분광분석을 통해서 acetic acid를 첨가한 compact layer의 투과도가 현저하게 높아진 것을 확인하였다. 이 결과는 $TiCl_4$ 처리에 의하여 compact layer를 구성하고 있는 $TiO_2$ 입자의 응집현상이 개선되므로 표면특성이 향상되었기 때문이다. Acetic acid를 첨가한 compact layer가 입자응집으로 인한 표면저항의 감소를 유발하여, 전자의 이동이 원활해진 것을 내부 임피던스 분석을 통하여 확인하였다. Compact layer에 의해 재결합이 감소하여 효율이 향상된 것을 I-V 특성곡선을 분석하여 확인하였다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.5
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• pp.511-517
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• 2016

Anthropometric data of the hand is one of the important issues for the product design related with hand and manual operation in terms of user-centered design. Direct measurement, which traditionally uses anthropometric measuring tool, has a few disadvantages in cumulation of measuring time, possible errors in raw data, doubtful reliability between inspectors. Newly introduced 3D scanning technology overcomes those disadvantages; however, another disadvantages, such as, hight cost and immovability, have been introduced. In this study, photogrammetric approach was introduced for the measurement of anthropometric data in hand. In order to minimize the possibility of error during direct and indirect measurement, a simulated object was used and effectiveness of photogrametric measurement was confirmed for the collection of anthropometric data in hand.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.2
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• pp.112-119
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• 2009

This paper presents a PLL(Phase Lock Loop) approach for effective speed and torque control of high speed miniature BLDCM(Brushless DC Motor) using hall sensor. The proposed speed control method based on PLL uses only a phase shift between reference pulse signal according to speed reference and actual pulse signal from hall sensor. It doesn't use any speed calculation, and calculates a direct current reference from phase shift. The current reference is changed to reduce the phase shift between reference and actual pulse. So the actual speed can keep the reference speed. The proposed control scheme is very simple but effective speed control is possible. In order to obtain a smooth torque production, the reference current is changed using acceleration and deceleration slope. The proposed control scheme is verified by experimental results of the 50W, 40,000[rpm] high speed miniature BLDCM.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.8-8
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• 2010

외부전하를 감지할 수 있는 EEPROM 구조를 기반으로 한 센서를 제안하였다. 부유게이트로부터 확장된 큰 면적의 접촉부위 (CCM)는 외부전하를 고정화하도록 설계되었으며, $0.13{\mu}m$ 단일-다결정 CMOS 공정에 적합한 적층의 금속-절연체-금속 (MIM) 제어케이트구조로 구성되었다. N-채널 EEPROM의 CCW 캐패시터 영역에 양의 전압이 인가되면 제어 게이트의 문턱전압이 음의 방향으로 변화하여 드레인 전류는 증가하는 특성을 보였다. 또한 이미 충전된 외부 캐패시터가 CCW의 부유게이트의 금속영역에 직접 연결되면, 외부 캐패시터로부터 유입된 양의 전하는 n-채널 EEPROM의 드레인 전류를 증가시키지만 반면에 음의 전하는 이를 감소시켰다. 외부 전압과 전하에 의해 PMOS의 특성은 NMOS에 비교하여 반대로 나타남이 확인되었다. EEPROM 인버터의 CCW 영역에 외부전하를 연결하면 인버터의 입-출력 특성이 기준 시료에 비해 외부전하의 극성에 따라 변화하였다. 그러므로, EEPROM 인버터는 외부전하를 감지하여 부유게이트에 고정된 전하의 밀도 크기에 따라 출력을 전압으로 표현할 수 있음을 확인하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.6
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• pp.1-7
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• 1971

This paper describes concerning the method of measurement for the intensity of ultrasonics in liquid. The probe which is added two sensive point of thermocople which is surrounded by the absorbed material of sonic wave on the both side of the refleftite plate have measured the intensity of ultrasonics indirectly by the difference of the temperature of two sensive point which had raised the temperature by the sonic wave and its reflective wave which transmitted the ultrasonic energy. This minify the influence from the temparature of liquid and time constant. Consequently, this is the basic industrial method which is with in the bounds of possibility on the simple measurement of the intensity of the local ultrasonics concerning direction of its propagation.

• The Journal of Society for e-Business Studies
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• v.12 no.2
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• pp.1-16
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• 2007

Recently the computing environment has been moved to open architectures that include Web technologies. Web Service is one of import component of the new paradigm. This paper presents a design and implementation of GIS Web Service for mobile devices. As many mobile devices are equipped with GPS (Global Positioning System), it is required to handle the position information more effectively. We have extended the proxy program in the client device to actively send the context information to the server. Based on the context information the server determines the optimal service mode to a particular client. A working example of location?based GIS Web Service is also presented. By using Web Service standards and XML messages we can achieve the maximal interoperability for heterogeneous mobile devices.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.108-113
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• 2011

In this paper, we propose a new method for robot navigation control through EMG and acceleration sensors which is attached to wrist. The method can remote control with intuitive motion like driving a car. It decide to control whether or not through EMG signal processing. And motion inferring through signal processing from acceleration sensor. Inferred motion is mapped to control command such as 'Forward', 'Backward', 'Left', 'Right'. Accuracy of each motions are over 99%. Control is capable naturally without time delay. Entire system has been implemented and we verified its utility through demonstration.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.371-379
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• 2011

In this paper, we propose a development methodology of interactive stereoscopic image display system. In our case, we consider a multiple touch recognition technique as the interaction method. That's because we want to guarantee multiple user access and interaction to the content without any restriction. In this case, however, some restrictions are occurred on account of the distance between display and participants. For this reason, this paper propose an invisible interaction surfaces which are generated in the air. This surface is utilized as interaction medium instead of the display wall. We also present an effective way to generate and edit interactive stereoscopic images based on Game Engine.