• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.20_21
• /
• 2009

전력거래소는 국내 유일하게 한국의 전력계통을 실시간으로 감시 제어하고, 계통의 안전성을 평가 후 최적으로 운용하기 위해 2002년부터 현 EMS 시스템을 운용해 오고 있다. 초기 모든 계통해석의 근간이 되는 상태추정의 운용을 위해 계통모델과 필요 취득 데이터를 대폭 정비하였다. 현재는 154kV 무인 변전소의 탭을 추가취득 하고 모든 아날로그 취득데이터의 그룹별 가중치 조정에 의한 상태추정 등 계통해석의 정도개선 노력을 지속적으로 추진해오고 있다. 또한 상정고장 개소와 발변전소 3상 단락 고장 개소를 대폭 확대 정비하여 예상되는 모든 고장에 급전원이 신속히 대처할 수 있도록 하였다. 또한 무효전력 제어를 통한 계통손실 최소화 방안의 합리적 도출을 위한 최적화 기능의 실시간 계통운용 등 괄목한 성과를 거두었다. 본고에서는 이들 EMS 계통해석 기능을 중심으로 현재의 활용실태와 미래의 방향에 대하여 소개하고자 한다.

• 기계와재료
• /
• v.22 no.1
• /
• pp.46-53
• /
• 2010

공작기계에서 가공정밀도를 저하시키는 가장 큰 요인은 열변형 및 채터진동이다. 본 고에서는 이 중 장시간 가공중 기계의 열변형에 따른 문제점을 자동으로 공작기계 CNC(Computerized Numerical Controller) 제어기상에서 실시간으로 보상하여 주는 장치 및 기술개발 사례에 대한 내용을 언급하고자 한다. 기계가공에서 온도신호의 실시간 데이터 취득 및 열변형에 따른 공작기계 원점(Work Offset)의 자율보정이 가공정밀도 향상 및 가동률 향상에 많은 영향을 끼친다 이에 따라 본 고에서는 온도 데이터의 취득부와 보상을 위한 보정값 추출을 위한 선형회귀법 및 신경회로망의 보정모델을 임베디드화한 디바이스와 CNC상에서 가공중 공작기계 원점 자동보정을 하는 시스템을 개발하였기에 관련내용을 소개하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.1564-1566
• /
• 2010

본 논문에서는 유헬스 시스템에 가장 기본이 되는 생체정보 측정에 대하여 하나의 휴대용 인터페이스만을 가지고 다양한 생체정보 측정기와 연계하여 다양한 생체정보를 취득할 수 있도록 하는 이식성 있는 임베디드 미들웨어로써 특히 체지방측정을 위한 체지방 센서 노드(BSN)의 설계 및 구현에 관한 것이다. BSN은 U-health 서비스를 제공하기 위해 측정기 자동인식, 데이터 취득, 위험요소 표시 및 데이터 수집장치(DAS)와의 통신을 담당하는 기능을 갖는다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.23 no.2
• /
• pp.109-116
• /
• 2005

3D Spatial Data, namely 3D Urban CG model express the building, road, river in virtual world and accumulate, manage the data in the GIS system. It is important infrastructure which expected in many usages. Recently 3D CG urban model needs much manual effort, time and costs to build them. In this paper, we introduce the integration of GIS, CG and automatic production of the $\lceil$3D Spatial Data Infrastructure$\rfloor$. This system make filtering, divide the polygon, generate the outlines of the GIS building map, design the graphic and property information and finally make automatic 3D CG models.

• Korean Journal of Remote Sensing
• /
• v.37 no.3
• /
• pp.577-589
• /
• 2021

Drone mapping systems can be applied to many fields such as disaster damage investigation, environmental monitoring, and construction process monitoring. To integrate individual sensors attached to a drone, it was essential to undergo complicated procedures including time synchronization. Recently, a variety of composite sensors are released which consist of visual sensors and GPS/INS. Composite sensors integrate multi-sensory data internally, and they provide geotagged image files to users. Therefore, to use composite sensors in drone mapping systems, mapping accuracies from composite sensors should be examined. In this study, we analyzed the mapping accuracies of a composite sensor, focusing on the data acquisition area and pre-calibration effect. In the first experiment, we analyzed how mapping accuracy varies with the number of ground control points. When 2 GCPs were used for mapping, the total RMSE has been reduced by 40 cm from more than 1 m to about 60 cm. In the second experiment, we assessed mapping accuracies based on whether pre-calibration is conducted or not. Using a few ground control points showed the pre-calibration does not affect mapping accuracies. The formation of weak geometry of the image sequences has resulted that pre-calibration can be essential to decrease possible mapping errors. In the absence of ground control points, pre-calibration also can improve mapping errors. Based on this study, we expect future drone mapping systems using composite sensors will contribute to streamlining a survey and calibration process depending on the data acquisition circumstances.

• The Journal of the Acoustical Society of Korea
• /
• v.29 no.5
• /
• pp.303-313
• /
• 2010

This paper describes an acoustic communication receiver structure, which is designed for QPSK (Quadrature Phase Shift Keying) signal with 25 kHz carrier frequency and 5 kHz symbol rate, and takes samples from received signal at 100 kHz sampling rate. Based on the described receiver structure, optimum design parameters, such as number of taps of FF (Feed-Forward) and FB (Feed-Back) filters and forgetting factor of RLS (Recursive Least-Square) algorithm, of joint equalizer are determined to minimize the BER (Bit Error Rate) performance of the joint equalizer output symbols when the acquisition data in shallow water using implemented acoustic transducers is decimated at a rate of 2:1 and then enforced to the input of receiver. The transmission distances are 1.4 km, 2.9 km, and 4.7 km. Analysis results show that the optimum number of taps of FF and FB filters are different according to the distance between source and destination, but the optimum or near optimum value of forgetting factor is 0.997. Therefore, we can reach a conclusion that the proper receiver structure could change the number of taps of FF and FB filters with the fixed forgetting factor 0.997 according to the transmission distance. Another analysis result is that there are an acceptable performance degradation when the 16-tap-length simple filter is used as a low-pass filter of receiver instead of 161-tap-length matched filter.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.1
• /
• pp.21-30
• /
• 2024

In this paper, we propose a method to build a sample dataset of the features of eight sensor-only facilities built as infrastructure for autonomous cooperative driving. The feature extracted from point cloud data acquired by LiDAR and build them into the sample dataset for recognizing the facilities. In order to build the dataset, eight sensor-only facilities with high-brightness reflector sheets and a sensor acquisition system were developed. To extract the features of facilities located within a certain measurement distance from the acquired point cloud data, a cylindrical projection method was applied to the extracted points after applying DBSCAN method for points and then a modified OTSU method for reflected intensity. Coordinates of 3D points, projected coordinates of 2D, and reflection intensity were set as the features of the facility, and the dataset was built along with labels. In order to check the effectiveness of the facility dataset built based on LiDAR data, a common CNN model was selected and tested after training, showing an accuracy of about 90% or more, confirming the possibility of facility recognition. Through continuous experiments, we will improve the feature extraction algorithm for building the proposed dataset and improve its performance, and develop a dedicated model for recognizing sensor-only facilities for autonomous cooperative driving.

• Proceedings of the KIEE Conference
• /
• 2001.05a
• /
• pp.266-269
• /
• 2001

컴퓨터 기술과 통신. 네트워크 기술의 발달로 전력설비의 보호방식은 단순한 보호 기능 외에 전체 시스템을 자동으로 보호. 제어하는 추세로 발전하게 되었다. 이러한 새로운 보호개념을 구축하기 위해서는 디지털형 보호계전기와 이를 네트워크로 엮는 통신 기술, 데이터를 취득 가공. 관리하는 데이터 처리 기술이 필수적이다. 본 논문에서는 변전소 자동화 시스템에 필수적인 디지털 보호계전기의 개발 사례와 변전소 자동화 시스템의 네트워크 구성 및 데이터처리 방법을 소개하고 있다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.5
• /
• pp.689-699
• /
• 2022

Recently, high productivity capabilities have been improved due to the application of advanced technologies in various industries, but in the construction industry, productivity improvements have been relatively low. Research on advanced technology for the construction industry is being conducted quickly to overcome the current low productivity. Among advanced technologies, 3D scan technology is widely used for creating 3D digital terrain models at construction sites. In particular, the 3D digital terrain model provides basic data for construction automation processes, such as earthwork machine guidance and control. The quality of the 3D digital terrain model has a lot of influence not only on the performance and acquisition environment of the 3D scanner, but also on the denoising, registration and merging process, which is a preprocessing process for creating a 3D digital terrain model after acquiring terrain scan data. Therefore, it is necessary to improve the terrain scan data processing performance. This study seeks to solve the problem of density inhomogeneity in terrain scan data that arises during the pre-processing step. The study suggests a 'pixel-based point cloud comparison algorithm' and verifies the performance of the algorithm using terrain scan data obtained at an actual earthwork site.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.3
• /
• pp.113-118
• /
• 2015

High-power semiconductor devices and microprocessors in factory electrical installation so sensitive to power quality measurements such as harmonic currents, voltage fluctuations, flicker, current imbalance. Therefore, the little change of power quality can influences the productivity of factory electrical machines. Troubleshooting these problems requires accurate measurements and analysis of power quality with monitoring instruments that can effectively locate issues and identify solutions. In this paper, the author presents hand-held power quality monitoring system to locate issues and identify solutions. The proposed system consists of two parts, One is to develop hand-held power meters by using NI(National Instrument) DAQ(Data Acquisition) and WLAN. Another is develop power quality monitoring MMI(Man-Machine Interface) using LabView software. To demonstrate the validity of the proposed algorithm, variable tests are carried out.