• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.12
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• pp.665-672
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• 2000

This paper described the measurement technology to analyze the partial discharge characteristics for long term aging of insulations. This system was consisted of high voltage generation and measurement part, PD detection part, digital conversion and signal processing part. We used the VXI system for digital conversion and signal processing part. In the digital conversion part, we studied the error of partial discharge magnitude and memory capacity for reading digital signal with the sampling rate. In the signal processing part, we showed the program algorithm to count pulses and read peak values of partial discharge. The allowable minimum sampling rate of digizer was decided to 250kS/s through analyzing test. We confirmed that this system was very useful in the study of $\phi-q-n$ characteristics of long term PD experiments with specimens being consisted of internal void defects and CIGRE II electrodes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.191-197
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• 2002

Recently, with the eye-opening progress in the related field of computer, the development of high resolution digital camera enables more precise positioning in digital photogrammetry, and a lot of interest has been concentrated on its application. In this study, the algorithm and system which enable the measurement of 3D point more easily was developed by image pointing method using digital image, when the digital map of the Cultural Properties of Architectures in Modern Ages is drawn by photogrammetry. As a result, we can reduce the limitation of surveying control point, exposure condition, and construct the digital map and 3D model of architecture more efficiently.

• Journal of Energy Engineering
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• v.11 no.3
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• pp.230-236
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• 2002

In real-time power system control, it is essential to measure the power system variables which are voltage, current, real and reactive power, power factor, system frequency and etc. These variables can be estimated or calculated by the synchronized phasor informations of voltage and current. Therefore, the synchronized phasor measurement of voltage and current is very important to real-time power system control. So, we develop SPMD (Synchronized Phasor Measurement Device) for synchronized phasor measurement of voltage and current. In this paper, we present the design and implementation of SPMD for real-time phasor measurement and the test results of developed SPMD on 380 V 3 phase distribution line in laboratory with resistor load and RTDS (Real Time Digital Simulator).

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.185-199
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• 1994

This study has been performed to present a new automatic tool wear measurement by digital image processing. The purpose of this paper is to develop an automatic tool wear measuring system based on the image processing which can be applied to the quasi-real time measurement of the characteristics of insert tip in turning. Tool wear monitoring is one of the key-problems, for the development of control systems of modern unmanned factory which are not completely solved now. In oredr words at present complete qualitative and quantitative information on tool wear morphology is required, at least on the following aspects : flank wear, its dimensions and distribution on the maximum and mean values on VB pqrqmeter in the various zones of the wearland. crater wear, its main dimensions and values of KT parameters. This research has been performed to this technique made possible by designing a proper lighting system to the worn tool with following features : The flank wear is measured by observing the active cutting part from a proper direction and by lighting the wearland by a diffuser optic system. The crater wear is visualized by lighting the tool by a He-Ne gas laser system developed in this study. By means of this system it is research to evaluate classical parameters of tool wear and to have complete information about tool wear morphology.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.625-629
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• 2012

This paper is presented to prepare NGN quality assurance management process under the quality system test methodology. The process should be drawn for NGN quality measurement framework of multimedia traffic. NGN test bed management process model are QoS measurement metrics, measurement interval meter above, and measuring tools, measuring equipment, measurement methods and measurement results from a series of processes for the analysis and methodology. This model, NGN quality assurance activities should be utilized in the future. Quality target level only when themselves constantly measured and managed, does not guarantee the communication quality of service. It is sensitive to the importance of NGN network technology paradigm for research on quality management in the NGN.

• Wind and Structures
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• v.20 no.2
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• pp.315-326
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• 2015

To overcome the drawbacks of the traditional contact-type sensor for structural displacement measurement, the vision-based technology with the aid of the digital image processing algorithm has received increasing concerns from the community of structural health monitoring (SHM). The advanced vision-based system has been widely used to measure the structural displacement of civil engineering structures due to its overwhelming merits of non-contact, long-distance, and high-resolution. However, seldom currently-available vision-based systems are capable of realizing the synchronous structural displacement measurement for multiple points on the investigated structure. In this paper, the method for vision-based multi-point structural displacement measurement is presented. A series of moving loading experiments on a scale arch bridge model are carried out to validate the accuracy and reliability of the vision-based system for multi-point structural displacement measurement. The structural displacements of five points on the bridge deck are measured by the vision-based system and compared with those obtained by the linear variable differential transformer (LVDT). The comparative study demonstrates that the vision-based system is deemed to be an effective and reliable means for multi-point structural displacement measurement.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.5 s.110
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• pp.514-520
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• 2006

In this study, the performance of a digital pile rebounding and penetration monitoring system (DPRMS) is evaluated and the measurement precision of the DPRMS is improved. The DPRMS is a high speed line-scanning camera system to measure the rebound and penetration of a pile in a construction work. A main problem in the DPRMS is a measurement error, which is caused by a shock or vibration due to a hammer impact. The measurement error is investigated by analyzing vibration signals of the DPRMS during the impact. Moreover, the frequency response functions of the DPRMS are also analyzed. As a result, it is found that the tripod height has an influence on the DPRMS performance and a shorter tripod is better. One more founding in this study is that the DPRMS should be placed with a appropriate distance from a pile for improving the measurement precision.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.250-255
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• 2011

This paper dealt with the design, fabrication and application of a risk voltage measurement system (RVMS) which analyzes the step and touch voltages in electrical grounding systems. The RVMS supply 300 V and 1.4 A in ranges from 40 Hz to 1 kHz as the test power source. A DAQ module having resolution of 400 kS/s and 16 bit is equipped with 7 inputs for measuring voltage and current. Also, a noise elimination algorithm of digital filter was applied to reduce the measurement error caused by external noises as a commercial frequency current. The performance of the RVMS was evaluated by measurement of the step and touch voltage according to the IEEE standard 80 and 81 in a grounding system with a 10 m counterpoise. The result showed that the RVMS analyzes the risk voltage with the error below 5%.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.15-21
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• 2019

In order to secure the safety of various machinery, it is very important to develop a technique for accurately and quickly measuring the cracks generated in the mechanical equipment and evaluating the mechanical characteristics. The evaluation of the mechanical properties is accompanied by an appropriate strain measurement according to the material and crack occurrence of the target structure. Especially, when micro cracks are generated, the evaluation method is very important. Digital image correlation is an optical full field displacement measuring method which is using currently with speckles in the interested area. However the evaluation method and conditions of image distributions have to be considered carefully to measure the crack occurrence because the images of the speckle patterns affect the quality of displacement results. In this study, the speckle pattern density is characterized to improve the accuracy of the measurement method. And also the micro crack initiation is detected by the measured displacement in the adopted speckle pattern distribution. It is shown that the proposed method is useful to determine the density pattern distribution for the accurate measurement and crack detection.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.225-236
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• 2014

Productivity of public organizations was far older due to issue more difficult to measure than private organizations. Unlike the private sector, the public sector is a diverse and sometimes conflicting objectives (efficiency, effectiveness, equity, democracy, etc.) exist, it is difficult to measure productivity in a single index. Many departments of government is intricately interrelated and sometimes produced by the joint efforts, it is difficult to allocate performance, incentives and accountability to among departments. And there is the difficulty of collecting data on the productivity indicators of public organizations. Despite these difficulties, we developed a productivity index system and measuring method to systematically introduce the concept of productivity in the local administration. In this paper, the productivity and the productivity index measurement practices of local governments conducted annually from 2011 on was deep into research. First, the report found examples of the governments of the developed countries, productivity measurement, then the way MOPAS(Ministry of Public Administration and Security) measure productivity index of local governments, success factors, the implications were in-depth analysis. Finally, in order to enhance productivity and competitiveness municipalities studied ways to take advantage of the productivity index.