• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.2
• /
• pp.174-184
• /
• 2013

For the successful R&D and deployment of LED-based green energy lighting systems, the real-time power quality measurement of both various non-linear power signals including pulse waveform, spike waveform, etc and the undesired-signals including harmonics, sag, swell, etc is required. In this paper, we propose a low-cost power quality measurement (PQM) method for low- (60Hz-several KHz) to high-frequency (several tens KHz) power signals, which are generated by green-energy lighting systems, and implement a PQM testbed using TI TMS320F28335 MCU. The proposed algorithm is programmed using C in the CCS (Code Composer Studio) 3.3 environment and is verified using test signals generated by an arbitrary signal generator, NF-WF1974. In the implemented testbed, we can measure various non-linear current signals that LED SMPS generates, analyze harmonics by fast Fourier transform, and test sag, swell, and interruption using wavelet transform.

• Journal of the Speleological Society of Korea
• /
• no.95
• /
• pp.15-21
• /
• 2009

Global village warming and carbon dioxide CO2 gas, and the human efforts for their healing and necessary alternative technology would be much more difficult things than that of making necessary funds and efforts to lay to sleep angry nature on the earth. The limited natural resources of fossil fuel would be dried up in several decades, and the intensity of diplomatic negotiations for natural resource guarantee among countries may be showed looking alike an war. The drain of fossil fuel called a new word of alternative policy like an environment-friendly green-growth, and the solar-cell and lighting technology for the solar energy applications were developed still more repeatedly day by day from oil lantern to LED high-tech illumination in great economy. Therefore, it was studied that the low-carbon green-growth illumination technology in cave applications with SOLAR-LED system which was produced and unified in connection with solar-cell and LED from the semiconductor production technology, and it was also clarified in necessary with useful cave lighting in heatless and with no photosynthesis of plant production in underground space.

• Journal of Convergence for Information Technology
• /
• v.8 no.6
• /
• pp.243-249
• /
• 2018

In this paper, we analyzed the effect of modulation scheme and modulation scheme on the dimming level of visible light communication system and studied the effect of distortion due to delayed signal. Currently, the modulation schemes most commonly used in visible light communication result in increasing the communication performance but reducing the brightness of the entire illumination. Continuous Burst Zero Duration will severely degrade lighting. This degrades not only the illumination but also the performance of the whole system and causes Flicker phenomenon. In this paper, we analyze the relationship between modulation technique and illumination - communication performance and investigate the effect of signal delay on visible light communication system. Through simulation, we analyze the performance of IPI-OOK which has the best communication-lighting performance and propose future research directions accordingly.

• The KIPS Transactions:PartB
• /
• v.12B no.1 s.97
• /
• pp.9-16
• /
• 2005

This paper focuses on the study of the face authentication system and the robustness of fact authentication methods under illumination changes. Four different face authentication methods are tried. These methods are as fellows; PCA(Principal Component Analysis), GMM(Gaussian Mixture Modeis), 1D HMM(1 Dimensional Hidden Markov Models), Pseudo 2D HMM(Pseudo 2 Dimensional Hidden Markov Models). Experiment results involving an artificial illumination change to fate images are compared with each other. Face feature vector extraction based on the 2D DCT(2 Dimensional Discrete Cosine Transform) if used. Experiments to evaluate the above four different fate authentication methods are carried out on the ORL(Olivetti Research Laboratory) face database. Experiment results show the EER(Equal Error Rate) performance degrade in ail occasions for the varying ${\delta}$. For the non illumination changes, Pseudo 2D HMM is $2.54{\%}$,1D HMM is $3.18{\%}$, PCA is $11.7{\%}$, GMM is $13.38{\%}$. The 1D HMM have the bettor performance than PCA where there is no illumination changes. But the 1D HMM have worse performance than PCA where there is large illumination changes(${\delta}{\geq}40$). For the Pseudo 2D HMM, The best EER performance is observed regardless of the illumination changes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.188-191
• /
• 2013

In this paper, in order to economize energy inside the vertical-type water treatment plant, a chamber-illumination-LED control board, which operates via nature light or human's touches, is proposed. Moreover, this illumination control process is contrived to be wirelessly monitored in real-rime. In addition, Zigbee communication code is programmed to implement the control board's function of wireless data transmission and automatic LED brightness control. The presented control method contrives brightness to be adjusted in real-time by dimming control, which means nature light changes control, so that the interior energy can realize the maximum energy conservation.

• Annual Conference of KIPS
• /
• 2012.11a
• /
• pp.1311-1314
• /
• 2012

최근에는 LED 조명으로 인해 조명 제어의 유연성이 높아짐에 따라 가정이나 사무공간에서 해당 공간의 목표 조도를 설정하고 현재 내부조도의 상황에 따라 자동으로 조명을 디밍하는 형태로 연구가 이루어지고 있다. 그러나 이러한 제어방식이 현재 주택용 요금제도로 운영 중인 고정요금제에서는 에너지 비용을 감소시키나, 스마트그리드에서 운영될 RTP(Real Time Pricing)에서는 요금 단계에 따라 오히려 에너지 비용이 증가될 수 있다. 이에 본 논문은 실시간 요금 단계에 따라 LED 조명의 목표 조도를 가변적으로 변화시켜 조명 에너지 비용을 최소화하고 사용자의 작업에 적합한 상황별 조도를 자동으로 제어하여 작업자에게 편리함을 제공하고자 한다. 이때 요금 단계에 따른 상황별 최저 및 최고 조도기준은 KSA 3011 및 IES를 참조하며, 최소한의 조명 에너지 사용을 위해 외부 광량을 최대한 활용하여 현재의 시간에 따라 블라인드의 Open/Close를 자동으로 서비스한다. 사용자의 상황은 PIR, Electric Powermeter, Piezoelectric 센서로부터 사용자의 위치, 가전기기 사용 유무, 착석 여부 등을 파악하고, RTP 요금에 따라 하루동안의 조명에 사용된 전력요금을 시뮬레이션한다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.11 no.3
• /
• pp.88-96
• /
• 1997

This paper analyzes the transients for parameters on electrical distribution system. We analyze the voltage sag and switching surge caused by reclosing and develope a distribution system model of multiground type using a practical data of 22.9(kV) distribution system. It is at customer that we analyze an affecting of reclosing through EMTP (Electromagnetic Transients Program) simulation, present transient phenomena on fault line and parallel line. Also. we analyze the various parameters affecting this phenomena in detail through parametric analysis. These factors include the fault location, load size, load power factor, capacitor bank size, and reclosing angle. And relation between these parameters and transient phenomena is presented.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.43 no.4 s.310
• /
• pp.1-10
• /
• 2006

This paper presents a development of a mobile sign language recognition system for daily communication of deaf people, who are sign dependent to access language, with hearing people. The system observes their sign by a cap-mounted camera and accelerometers equipped on wrists. To create a real application working in mobile environment, which is a harder recognition problem than lab environment due to illumination change and real-time requirement, a robust hand segmentation method is introduced and HMMs are adopted with a strong grammar. The result shows 99.07% word accuracy in continuous sign.

• Proceedings of the Korean Information Science Society Conference
• /
• 2007.10d
• /
• pp.500-504
• /
• 2007

CPMS(Classroom Power Management System)는 유비쿼터스 센서네트워크 기술을 적용한 층별 강의실 조명 전원을 관리하는 시스템이다. 강의실에는 조도를 센싱하는 모트와 조명 전원을 제어하는 모트가 설치되어 있어, 주기적으로 센서 데이터 및 강의실 전원 상태를 주기적으로 CPMS서버에 보고한다. CPMS 서버는 베이스 모트를 통해 각 강의실의 방의 제어 모트들과 통신하고 전원을 제어하고, 윈도우즈 GUI 소프트웨어를 통해 모트의 상태를 표시하고, 강의실 사용에 대한 스케줄을 입력하여 관리한다. 본 논문에서 CPMS는 모트간의 통신은 IEEE 802.15.4/Zigbee모듈을 사용하여 구현했고 서버소프트웨어는 윈도우즈 시스템을 기반으로 C# 언어와 MS SQL Server로 구현하였다. 본 시스템은 장치들 간의 통신이 모두 무선으로 이루어지므로 설치가 쉽고, 유선 공사에 드는 비용을 절감한 수 있을 뿐 아니라 유선 공사가 난감한 기존 빌딩에서도 구축할 수 있는 장점이 있다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.4
• /
• pp.31-38
• /
• 2011

In this paper, we propose an autonomous Indoor lighting control system in which indoor lighting devices are autonomously controlled such that electricity bills are minimized in our daily life. Our focus is to utilize Passive Infrared (PIR) sensors to detect the presence of human being indoor and automatically to control indoor lighting electric devices. A control algorithm is also devised to control the whole system. We justify the proposed system by demonstrating specific applications in our everyday life. Cost survey and experimental results also demonstrate the efficiency of the proposed system in real life.