• Title/Summary/Keyword: Positioning Light

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Enhanced Electron Emission of Carbon Nanotube Arrays Grown Using the Resist-Protection-assisted Positioning Technique

  • Ryu, Je-Hwang;Kim, Ki-Seo;Yu, Yi-Yin;Lee, Chang-Seok;Lee, Yi-Sang;Jang, Jin;Park, Kyu-Chang
    • Journal of Information Display
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    • v.9 no.4
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    • pp.30-34
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    • 2008
  • Field emitter arrays (FEAs) were developed using carbon nanotubes (CNTs) as electron emission sources. The CNTs were grown using a selective-positioning technique with a resist-protection layer. The light emission properties were studied through the electron emission of the CNTs on patterned islands, which were modulated with island diameter and spacing. The electron emission of CNT arrays with $5{\mu}m$ diameters and $10{\mu}m$ heights increased with increased spacing (from $10{\mu}m$ to $40{\mu}m$). The electron emission current of the $40-{\mu}m$-island-spacing sample showed a current density of 1.33 mA/$cm^2$ at E = 11 V/${\mu}m$, and a turn-on field of 7 V/${\mu}m$ at $1{\mu}A$ emission current. Uniform electron emission current and light emission were achieved with $40{\mu}m$ island spacing and $5{\mu}m$ island diameter.

Localization of a Mobile Robot Using Multiple Ceiling Lights (여러 개의 조명등을 이용한 이동 로봇의 위치 추정)

  • Han, Yeon-Ju;Park, Tae-Hyoung
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.4
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    • pp.379-384
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    • 2013
  • We propose a new global positioning method for the indoor mobile robots. The multiple indoor lights fixed in ceiling are used as the landmarks of positioning system. The ceiling images are acquired by the fisheye lens camera mounted on the moving robot. The position and orientation of the lights are extracted by binarization and labeling techniques. Also the boundary lines between ceiling and walls are extracted to identify the order of each light. The robot position is then calculated from the extracted position and known position of the lights. The proposed system can increase the accuracy and reduce the computation time comparing with the other positioning methods using natural landmark. Experimental results are presented to show the performance of the method.

A Study on Optical Element Alignment Automation using Ultra Precision Positioning Stage (극초정밀 위치제어장치를 이용한 광소자 정렬 자동화에 관한 연구)

  • Jeong S.H.;Kim H.U.;Choi S.B.;Kim G.H.;Park J.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.314-317
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    • 2005
  • As demands of VBNS and VDSL increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM elements increases. The alignment and the attachment technology are very important in the fabrication of optical elements. The ultra precision stage wasn't yet applied in the optical alignment and the optical element alignment was taken too many times. In this paper, the optical element alignment of ultra precision positioning stage was studied. The alignment algorithm is comprised of field search and peak search algorithms. The procedure of the alignment algorithms applied to the ultra precision positioning stage are developed by LabView programming.

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Air Purification System Using Combined Wavelengths of Ultraviolet Light Sources (신경망을 이용한 BLE의 RSSI 예측 기법)

  • Youm, Sungkwan;Lee, Yujin;Shin, Kwang-Seong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2021.05a
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    • pp.550-551
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    • 2021
  • Positioning technology is performing important functions in augmented reality, smart factory, and autonomous driving. Among the positioning techniques, the positioning method using beacons has been considered a challenging task due to the deviation of the RSSI value. In this study, the position of a moving object is predicted by training a neural network that takes the RSSI value of the receiver as an input and the distance as the target value. To do this, the measured distance versus RSSI was collected.

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Optimize OTDOA-based Positioning Accuracy by Utilizing Multiple Linear Regression Model under NB-IoT Technology (NB-IoT 기술에서 Multiple Linear Regression Model을 활용하여 OTDOA 기반 포지셔닝 정확도 최적화)

  • Pan, Yichen;Kim, Jaesoo
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2020.07a
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    • pp.139-142
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    • 2020
  • NB-IoT(Narrow Band Internet of Things) is an emerging LPWAN(Low Power Wide Area Network) radio technology. NB-IoT has many advantages like low power, low cost, and high coverage. However low bandwidth and low sampling rates also lead to poor positioning accuracy. This paper proposed a solution to optimize positioning accuracy under the OTDOA(Observed Time Difference of Arrival) approach by utilizing MLR(Multiple Linear Regression) models. Through the MLR model to predict the influence degree of weather(temperature, humidity, light intensity and air pressure) on the arrival time of signal transmission to improve the measurement accuracy. The improvement of measurement accuracy can greatly improve IoT applications based on NB-IoT.

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A study on indoor visible light communication localization based on manchester code using walsh code (Walsh code를 이용한 Manchester code 기반 가시광 통신 실내 위치인식에 대한 연구)

  • Kim, Won-yeol;Park, Sang-gug;Cho, Woong-ho;Noh, Duck-soo;Seo, Dong-hoan
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.9
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    • pp.959-966
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    • 2015
  • In this paper, we propose an indoor visible light communication(VLC) localization using Walsh code which can identify overlapped signals transmitted from the different LED sources as each of orthogonal signal at a receiver and using Manchester code which can eliminate the flicker of LED light and maintain a constant brightness. The proposed system can estimate the relative position of the receiver by using Lambertian radiation properties and trilateration method that are applied to the location information of fixed LED sources and the received signals from them. In order to verify the feasibility of the proposed system, we carried out the simulation in an indoor space with $6{\times}6{\times}1.5m^3$ installed LED lamps of 16. The simulation result shows that the proposed method achieves an average positioning error of 0.0536 m and a maximum positioning error of 0.2977 m.

A Model Stacking Algorithm for Indoor Positioning System using WiFi Fingerprinting

  • JinQuan Wang;YiJun Wang;GuangWen Liu;GuiFen Chen
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.17 no.4
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    • pp.1200-1215
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    • 2023
  • With the development of IoT and artificial intelligence, location-based services are getting more and more attention. For solving the current problem that indoor positioning error is large and generalization is poor, this paper proposes a Model Stacking Algorithm for Indoor Positioning System using WiFi fingerprinting. Firstly, we adopt a model stacking method based on Bayesian optimization to predict the location of indoor targets to improve indoor localization accuracy and model generalization. Secondly, Taking the predicted position based on model stacking as the observation value of particle filter, collaborative particle filter localization based on model stacking algorithm is realized. The experimental results show that the algorithm can control the position error within 2m, which is superior to KNN, GBDT, Xgboost, LightGBM, RF. The location accuracy of the fusion particle filter algorithm is improved by 31%, and the predicted trajectory is close to the real trajectory. The algorithm can also adapt to the application scenarios with fewer wireless access points.

Localization Techniques Based on Image Sensor and Visible Light Communication (이미지 센서 및 가시광 통신 기반 위치 추정 기술)

  • Le, Nam-Tuan;Ifthekhar, Md. Shareef;Mondal, Ratan Kumar;Jang, Yeong Min
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.1
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    • pp.37-41
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    • 2016
  • Localization is one of the key issues of demandable applications, especially smart services. Beside the traditional GPS based localization technique, the localization issue by visible light communications is promising market because of possibility of combining visible light communications with positioning technique for a high accurate, especially indoor localization service. This paper provides the overview and new image sensor scheme for localization issue based on visible light communication. The survey is introduced from core techniques to enhancement issues of localization. We hope these will be the essential references for the impact selection method in implementation and standardization issues.

Study of Stray-light Analysis and Suppression Methods for the Spectroscopic System of a Solar-radiation Observer Instrument

  • Zheng, Ru;Liu, Bo;Wang, Lingyun;Gao, Yue;Li, Guangxi;Li, Changyu
    • Current Optics and Photonics
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    • v.5 no.3
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    • pp.220-228
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    • 2021
  • To improve the measurement accuracy of a solar-radiation observer instrument, aiming at the problem of multiorder-stray-light interference caused by the diffraction of the flat-field concave grating in the spectroscopic system, straylight suppression methods for different forms of optical traps are studied. According to the grating surface-scattering distribution-function model, the bidirectional scattering distribution function (BSDF) of a dust-polluted surface and the flat-field concave grating's transition area of the spectroscopic system is calculated, and a Lyot stop with blade baffle is designed to suppress this kind of stray light. For diffraction multiorder stray light, based on the theory of light-energy transmission, a design for precise positioning of the trench optical trap is proposed. The superiority of the method is verified through simulation and actual measurement. The simulation results show that in a spectroscopic system approximately 160 mm × 140 mm × 80 mm in size, the energy of the stray light is reduced by one order of magnitude by means of the trench optical trap and Lyot stop, and the number of beams is reduced from 5664 to 1040. The actual measurements show that the stray-light-suppression efficiency is about 69.4%, which is effective reduction of the amount of stray light.

RASE Acquisition Algorithm of Ultra Wideband System for Car Positioning and Traffic Light Control (차량 위치추적기반 교통신호등 제어용 UWB 시스템의 Acquisition 알고리즘 연구)

  • Hwang, In-Kwan;Park, Yun-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.10C
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    • pp.992-998
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    • 2005
  • In this paper, An Ultra Fast Acquisition Algorithm of low transmission rate ultra-wideband(UWB) systems for car positioning and traffic light controling is proposed. Since the acquisition algorithms for CDMA system are not fast enough to access the low transmission rate UWB systems, the new ultra fast acquisition scheme which can be implemented with low cost and simplified circuit is required. The proposed algorithm adopted the Recurrent Sequential Estimation scheme and trinomial M-sequence. Therefore, The proposed scheme can reduce the average acquisition time in $1\~3{\mu}sec$ with simple circuit, even for the UWB systems which use long pseudo-noise(PN) sequence and transmit low power below the FCC EIRP emission limits. The simulation results for the average acquisition time of the proposed scheme are compared with the ones of the existing acquisition schemes.