• Title/Summary/Keyword: measurement accuracy

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Global Navigation Satellite System(GNSS)-Based Near-Realtime Analysis of Typhoon Track for Maritime Safety (해상안전을 위한 GNSS 기반 태풍경로 실시간 분석)

  • LEE, Jae-Kang;HA, Ji-Hyun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.1
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    • pp.93-102
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    • 2019
  • In this study, in order to analyze the possibility of observing a typhoon track based on the Global Navigation Satellite System(GNSS), Typhoon NARI, the 11th typhoon of 2007, was analyzed in terms of the typhoon track as well as the local variation of perceptible water over time. The perceptible water was estimated using data obtained from observatories located on the typhoon track from Jeju to the southern coast of Korea for a total of 18 days from September 7(DOY 250) to September 24(DOY 267), 2007, including the period when the observatories were affected by the typhoon at full-scale, as well as one previous week and one following week. The results show that the trend of the variation of perceptible water was similar between the observatories near the typhoon track. Variation of perceptible water over time depending on the development and landing of the typhoon was distinctively observed. Several hours after the daily maximum of perceptible water was found at the JEJU Observatory, the first struck by the typhoon on the typhoon track, the maximum value was found at other observatories located on the southern coast. In the observation period, the time point at which the maximum perceptible water was recorded in each location was almost the same as the time point at which the typhoon landed at the location. To analyze the accuracy of the GNSS-based perceptible water measurement, the data were compared with radiosonde-based perceptible water data. The mean error was 0.0cm, and the root mean square error and the standard deviation were both 0.3cm, indicating that the GNSS-based perceptible water data were highly accurate and precise. The results of the this study show that the GNSS-based perceptible water data may be used as highly accurate information for the analysis of typhoon tracks over time.

Analysis of the Dead Layer Thickness effect and HPGe Detector by Penelope Simulation (Penelope Simulation에 의한 불감층 두께 효과 및 HPGe 검출기 분석)

  • Jang, Eun-Sung;Lee, Hyo-Yeong
    • Journal of the Korean Society of Radiology
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    • v.12 no.7
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    • pp.801-806
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    • 2018
  • Germanium crystals have a dead layer that causes efficiency deterioration because the layer is not useful for detection but strongly weakens the photons. Thus, when the data provided by the manufacturer is used in the detector simulation model, there is a slight difference between the calculated efficiency and the measured efficiency.The shape and dimensions of the high purity germanium (HPGe) detector were determined by CT scans to accurately characterize the shape for the Monte Carlo roll simulation. It is found that the adjustment of the dead layer is a good match with the relative deviation of ${\pm}3%$ between the measurement efficiency and the simulation efficiency at the energy range of 50 - 1500 keV. Simulation data were compared by varying the thickness of the dead layer. The new Monte Carlo simulations were compared with the experimental results to obtain new blank layer thicknesses. The difference in dead layer results for the 1.5 mm thick end cap simulation model in 1.4 and 1.6 mm thick End Cap simulation models was a systematic error due to the accuracy of the end cap dimensions. After considering all errors including statistical errors and systematic errors, the thickness of the detector was calculated as $1.02{\pm}0.14mm$. Therefore, it was confirmed that the increase in the thickness of the dead layer causes the effect to be effected on the efficiency reduction.

Improvement on Surveying Performance Evaluation for Public Surveying of Underground Facilities (지하시설물의 공공측량 성과심사 방법 개선에 관한 연구)

  • Jung, Choong Ho;KIM, Chong-Mun;KIM, Ki-Su;CHOI, Yun-Soo
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.2
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    • pp.15-23
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    • 2019
  • When the public surveying system was introduced in 1961, large scale surveying performances, such as infrastructure construction work, were dominant. However, due to changes in the environment, most of the current surveying performances focused on small scale underground facilities. The method of surveying underground facilities is as follows: "method of measurement before refilling after burying the pipeline" and "method of using exploration after refilling." There are advantages and disadvantages to each method. It became difficult to obtain the accuracy of the location of the underground facilities due to the fact that there were sections of the pipeline that had not been observed through exploration. Therefore, the 2017 performance evaluation regulations were revised. The revision included the addition of the "Underground Facilities Creation Period," a system that allows for surveys to be evaluated based on actual measurements. However, in this particular field, concerns about the advantages of exploration and the purpose of this study was to investigate the background and purpose of the limitations of the survey have been continuously raised. The purpose of this study was to investigate the background and purpose of the public surveying system and to identify the proportion of underground facilities surveying in comparison to public surveying. This study conducted surveys on the implementers of public surveying and those who did the actual surveying. The researcher has summarized the improvements that incorporate the analysis results and the field comments in the revised performance evaluation regulations in 2017.

Development of robot calibration method based on 3D laser scanning system for Off-Line Programming (오프라인 프로그래밍을 위한 3차원 레이저 스캐닝 시스템 기반의 로봇 캘리브레이션 방법 개발)

  • Kim, Hyun-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.16-22
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    • 2019
  • Off-line programming and robot calibration through simulation are essential when setting up a robot in a robot automation production line. In this study, we developed a new robot calibration method to match the CAD data of the production line with the measurement data on the site using 3D scanner. The proposed method calibrates the robot using 3D point cloud data through Iterative Closest Point algorithm. Registration is performed in three steps. First, vertices connected by three planes are extracted from CAD data as feature points for registration. Three planes are reconstructed from the scan point data located around the extracted feature points to generate corresponding feature points. Finally, the transformation matrix is calculated by minimizing the distance between the feature points extracted through the ICP algorithm. As a result of applying the software to the automobile welding robot installation, the proposed method can calibrate the required accuracy to within 1.5mm and effectively shorten the set-up time, which took 5 hours per robot unit, to within 40 minutes. By using the developed system, it is possible to shorten the OLP working time of the car body assembly line, shorten the precision teaching time of the robot, improve the quality of the produced product and minimize the defect rate.

A Study on Measures for Strengthening Intelligence-Led Policing Using HUMINT (휴민트를 이용한 정보지향적 경찰활동 강화방안)

  • Shin, Jae-Hun;Kim, Sang-Woon
    • The Journal of the Korea Contents Association
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    • v.19 no.2
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    • pp.112-120
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    • 2019
  • This study conducts survey on currently working police officers to examine the actual utilization of HUMINT and suggest measures for strengthening the effective intelligence police activity, Intelligence Led Policing. For the completeness of study, this study presented evidences based on survey data from police officers at sites and this study also suggested improvement measures. in regulating the scope of duty, "Act on the Performance of Duties by Police Officers" regulates that 'Gathering, preparation, and distribution of public safety information' is the duty of police officer and defines the information gathering activity of police as the unique work of police officer. Thus, in accordance with "Act on the Performance of Duties by Police Officers", police officers gather various information to prevent crimes and maintain orders. Among the information gathering methods used by police officer, HUMINT is the oldest measure and it is still utilized. HUMINT has the advantages of low expense, high accuracy, and critical impact on the other. Nevertheless, due to limitations in data objectification, measurement, and responses to double attack, HUMINT is underappreciated. With awareness on such HUMINT issues, this study conducted survey on in-service police officers and examined the actual state of HUMINT. Based on the survey result, this study suggested Intelligence-Led Policing as the effective application method.

A Study on the Improvement of Creativity of R&D Team in Government-Funded Research Institutes : Comparative Study on the Viewpoints of Leaders and Members (정부출연 연구기관 연구개발팀의 창의성 제고 관리방안에 관한 연구 : 부서장과 구성원 관점의 비교)

  • Roh, Poong-Du;Han, In-Soo
    • Journal of Korea Technology Innovation Society
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    • v.21 no.3
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    • pp.992-1020
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    • 2018
  • The purpose of this study is to investigate the ways to enhance the creativity of R & D teams of government-funded research institutes through systematic empirical studies. For this purpose, a research model was established based on existing research on group creativity and verified through empirical studies. Specifically, This study first attempts to investigate the influence that team diversity, team cohesion, team autonomy and team efficacy have on team creativity. Second, it intends to verify the mediating effects of team efficacy between team characteristics and team creativity. An empirical study was conducted on 102 R & D teams of government-funded research institutes. In the team creativity measurement, the evaluation by the leaders and the self evaluation of the members were performed in parallel. This is to increase the accuracy of the evaluation and to compare the differences of the viewpoints of the two subjects. The result of the analysis demonstrated that team cohesion among the others had a positive influence on team creativity, and that team efficacy possessed certain positive qualities in mediating the relationship between team diversity, team autonomy, and team creativity. Based on these findings, this study discussed its academic implications as well as its practical limitations, and made suggestions on future research tasks that remain.

Development of New Ocean Radiation Automatic Monitoring System (새로운 해양 방사선 자동 감시 시스템의 개발)

  • Kim, Jae-Heong;Lee, Joo-Hyun;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.23 no.2
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    • pp.743-746
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    • 2019
  • In this paper we proposed a new ocean radiation automatic monitoring system. The proposed system has the following characteristics: First, using NaI + PVT mixed detectors, the response speed is fast and precision analysis is possible. Second, the application of temperature compensation algorithm to scintillator-type sensors does not require additional cooling devices and enables stable operation in the changing ocean environment. Third, since cooling system is not needed, electricity consumption is low, and electricity can be supplied reliably by utilizing solar energy, which can be installed at the observation deck of ocean environment. Fourth, using GPS and wireless communications, accurate location information and real-time data transmission function for measurement areas enables immediate warning response in the event of nuclear accidents such as those involving neighboring countries. The results tested by the authorized testing agency to assess the performance of the proposed system were measured in the range of $5{\mu}Sv/h$ to 15mSv/h, which is the highest level in the world, and the accuracy was determined to be ${\pm}8.1%$, making normal operation below the international standard ${\pm}15%$. The internal environmental grade (waterproof) was achieved, and the rate of variation was measured within 5% at operating temperature of $-20^{\circ}C$ to $50^{\circ}C$ and stability was verified. Since the measured value change rate was measured within 10% after the vibration test, it was confirmed that there will be no change in the measured value due to vibration in the ocean environment caused by waves.

A Study for Comparison of Geometric Characteristics on Forearms for Improvement of Convinience in Splint Manufacturing with 3D Printing Technology (3D 프린팅 기술을 적용한 스플린트의 제작 용이성 향상을 위한 아래팔 기하 정보 비교에 관한 연구)

  • Chang, Ji Hong
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.5
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    • pp.475-481
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    • 2019
  • A splint is one of assisting devices for the disabled with hemiplegia or contracture and is manually made by an experienced expert. Heated thermoplastic materials are continuously fitted to the affected part. This traditional method has a possible risk of low-temperature burn, quality variance of the splint due to the proficiency of maker. etc. While various approaches has been made using 3D printing technology in order to redeem those disadvantages, they still carry high cost issues with 3D scanners or accuracy issues with manual measurement. This research begins with symmetrical characteristics of human body and focuses on the preliminary study for the possibility of splint manufacturing with 3D printing technology based on geometric characteristics of unaffected arm. 3D right and left forearm models of healthy male adults were created by photogrammetry software and a series of digital images in order to measure the circumference and cross-sectional area of the forearm models at every 20mm from the elbow. The circumference and cross-sectional area showed tolerable levels of differences between both sides within subjects; The circumference and cross-sectional area showed very strong correlations between both sides within subjects. From these findings, the possibility of splint manufacturing with 3D printing technology could be confirmed based on the geometric characteristics of unaffected side.

Vital Sign Detection in a Noisy Environment by Undesirable Micro-Motion (원하지 않는 작은 동작에 의한 잡음 환경 내 생체신호 탐지 기법)

  • Choi, In-Oh;Kim, Min;Choi, Jea-Ho;Park, Jeong-Ki;Kim, Kyung-Tae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.5
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    • pp.418-426
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    • 2019
  • Recently, many studies on vital sign detection using a radar sensor related to Internet of Things(IoT) smart home systems have been conducted. Because vital signs such as respiration and cardiac rates generally cause micro-motions in the chest or back, the phase of the received echo signal from a target fluctuates according to the micro-motion. Therefore, vital signs are usually detected via spectral analysis of the phase. However, the probability of false alarms in cardiac rate detection increases as a result of various problems in the measurement environment, such as very weak phase fluctuations caused by the cardiac rate. Therefore, this study analyzes the difficulties of vital sign detection and proposes an efficient vital sign detection algorithm consisting of four main stages: 1) phase decomposition, 2) phase differentiation and filtering, 3) vital sign detection, and 4) reduction of the probability of false alarm. Experimental results using impulse-radio ultra-wideband radar show that the proposed algorithm is very efficient in terms of computation and accuracy.

A Study on the Improvement Repeatability and Accuracy of the Analysis Method for SF6 of Trace Level (극미량 수준의 SF6 측정법에 따른 재현성 및 정확도 향상에 관한 연구)

  • Yoo, Heejung;Choe, Hongwoo;Lee, Sepyo;Kim, Jongho;Han, Sangok;Ryoo, Sangboom
    • Journal of the Korean Society of Urban Environment
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    • v.18 no.4
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    • pp.523-530
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    • 2018
  • Kyoto Protocol, adopted in 1997, set the obligation to reduce $CO_2$, $CH_4$, $N_2O$, HFCs, PFCs, and $SF_6$ in developed countries during 1st promised period. $SF_6$ has been drawing a lot of attention since the Kyoto Protocol because once it is released into the atmosphere, it not only stays in the atmosphere for more than 3,200 years but also emits 22,800 times stronger global warming potential at the same concentrations as $CO_2$ if remains in the atmosphere for 100 years. This study introduces 12 methods for $SF_6$ of measuring trace. $SF_6$ of trace level in the atmosphere correctly, the measurement method was changed and as a result, when the back flush method was applied to the pre-concentration system that used low-temperature concentration and high-temperature desorption system, which used Carboxen-1000 adsorption trap, the effect was the best.