• Title/Summary/Keyword: uniformity test

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A Study of Uniformity Test in PET/CT (PET/CT 장치의 uniformitly측정에 관한 연구)

  • Kim, Su-Keun;Jung, Hee-Il;Park, Soung-Ock
    • Journal of radiological science and technology
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    • v.29 no.1
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    • pp.13-19
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    • 2006
  • The PET scanner can detect the photon pair arriving from the source in phantom. The number of light photons released by the crystal(scintillator-BGO or LSO). In recent scintillation crystals in block structures were incorporated into full ring systems, and their resulted marked improvement in spatial resolution and increase in a sensitivity to annihilations. The uniformity of the crystal sensitivity is very important to makes correct information of abnormal states in organs. These factors influenced by the dection efficiency of the scintillators. We have study about the uniformity of crystals to the annihilation, And study about the standard deviation to average counts. The relative standard deviation in central detector groups more uniformed than circumferenced detector groups. It is caused detected quanta of gamma ray by the geometrical factors of PET detector. PET cameras are available with different geometric arrangement and several parallel rings oriented in the axial direction. The center groups from 7th to 40th groups are comparatively uniform and sensitive. But at the circumferenced detectors decreased the sensitivity and uniformity.

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An Experimental Study on the Ground Improvement of Waste Landfill (쓰레기매립지반 개량에 관한 실험적 연구)

  • Chon, Yong-Back;Jeong, Young-Gab
    • Journal of the Korean Society of Industry Convergence
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    • v.7 no.4
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    • pp.341-348
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    • 2004
  • This study experimented dividing compaction load by dynamic compaction test and an oil pressure hammer compaction test for consolidation strength characteristics experimental feedback about soil change aspect of waste landfill ground and revelation of compaction effect as underground research about consolidation behavior of waste landfill ground by compaction load, foot weight and percussion number of times were adapted differently each other with uniformity drop head when dynamic compaction test, and hammer scale and percussion number of times were adapted differently also when oil pressure hammer compaction test.

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Development of IIR Seeker Target Simulator (적외선영상 탐색기 표적 모의장치 개발)

  • Yun, Seok-Jae;Ryu, Dong-Wan;Hwang, Kang-Seok
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.4
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    • pp.441-448
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    • 2013
  • This paper describes the development of Target Simulator developed for performance test and failure detection of Imaging Infra-Red(IIR) seeker which is one of the most important equipments in specific cruise missile systems. The simulator makes it possible to test detecting and tracking performance for target, uniformity of IIR, FOV status and spatial resolving power. Besides, it includes several self-test functions and optic axis alignment methods to improve its own reliability.

Disturbing Factor Analysis of Radiated Susceptibility Test (전자파내성 시험의 방해 요인 분석)

  • Park, Yoon-hyun;Kim, Young-kil
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.76-82
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    • 2016
  • In this paper, EMC (electromagnetic compatibility) test standard KN61000-4-3 "radiated RF electromagnetic field and uniformity chapter immunity test" has been used in, this is the electric field strength to be uniformly applied at the time of the test based on environment to understand the elements of change to analyze the interference factor.

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Design and Implementation of Genetic Test-Sheet-Generating Algorithm Considering Uniformity of Difficulty (난이도 균일성을 고려한 유전자 알고리즘 기반 평가지 생성 시스템의 설계 및 구현)

  • Song, Bong-Gi;Woo, Chong-Ho
    • Journal of Korea Multimedia Society
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    • v.10 no.7
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    • pp.912-922
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    • 2007
  • Evaluation of distance teaming systems needs a method that maintains a consistent level of difficulty for each test. In this paper, we propose a new algorithm for test sheet generation based on genetic algorithm. Unlike the existing methods that difficulty of each test item is assigned by tutors, in the proposed method, that can be adjusted by the result of the previous tests and the average difficulty of test sheet can be consistently reserved. We propose the new genetic operators to prevent duplications of test items in a test sheet and apply the adjusted difficulty of each test item. The result of simulation shows that difficulty of the test sheet generated by proposed method can be more regular than the random method and the simulated annealing method.

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Analysis on Rainfall Distribution in a Large Experimental Rainfall Simulator with Fixed Nozzle Arrangement (고정식 노즐 배치를 가진 대형 강우모사장치의 강우 분포 특성 분석)

  • Lee, Chan-Joo;Kim, Jong Pil;Lee, Jin-Won;Kim, Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8116-8127
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    • 2015
  • This study provides results from the experiment on the rainfall distribution using a large Experimental rainfall simulator with fixed nozzle arrangement. Results from the experiment on the nozzles which are crucial for rainfall simulation show standard errors expressed as percentage are 0.15~0.38% at the indoor flow testing apparatus and 0.37~0.59% at the KICT-ERS. To examine spraying range of the nozzles, radial and triangular rainfall measurement test are done. In the radial test, coefficient of uniformity (CU) lies in 0.348~0.657 in the single nozzle spraying case, while it increases up to 0.854~0.895 in the seven nozzle spraying case. This means increase of both rain rate and uniformity by means of superimposition of spraying. The CU of the triangular test falls to 0.845~0.896. The results from the experiment on the whole-scale of the KICT-ERS show that CU exceeds 0.7 for every case except the one experimental condition where a $1.5{\phi}$ nozzle is used. The CU tends to increase with increasing rainfall intensity. Comparison with the previous studies shows that KICT-ERS provides rainfall distribution above average CU.

A Study on the Evaluation of Lighting Performance in an Office Space (사무공간의 조명성능 평가에 관한 연구)

  • 김한성;김영민;김강수
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.6
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    • pp.16-22
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    • 2003
  • The purpose of this study was to provide visual evaluation data in a workstation space when different lighting types were applied. For the performance evaluation, Radiance program was used for simulations, and the mock-up room(15.0x11.6x3m) was used for the actual test. The results of this study were as follows; 1) When the inidirect lighting simulation data using Radiance was compared with the actual data in a small workstation space, there was a 6.5% difference. Therefore, Radiance program was proved to be useful for the evaluation of lighting performance. 2) Higher light levels (higher light ratio (%)) were recorded in the straddled layout and lower light levels (lower light ratio (%)) were recorded in the centered layout condition in most cases. 3) Also, the results show that the indirect luminaires and the straddled layouts provide higher uniformity, whereas the direct luminaires and the centered layouts have lower uniformity.

Analysis of Solar Simulator's Uncertainty Factor for Photovoltaic Module's I-V curve test (PV모듈의 I-V특성 시험을 위한 Solar Simulator의 측정불확도 요인 분석)

  • Kang, Gi-Hwan;Park, Chi-Hong;Kim, Kyung-Soo;Yu, Gwon-Jong;Ahn, Hyung-Keun;Han, Deuk-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.5-7
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    • 2006
  • In this paper, we analyzed the elements of measurement uncertainty on electrical performance test which are the most important things in photovoltaic module performance test. Repeating the performance test by 6 men, the measurement uncertainty could be calculated. In this experiment, Solar Simulator (A-Class pulse type) used for domestic certificate test of PV module is Pasan IIIb (Balval, Switzerland). The possible elements of the measurement uncertain that could effect electrical performance test of PV module are reference cell, spectrum correction, error from measurement repetition, test condition, stability and uniformity of artificial solar simulator. To find the measurement uncertainty, 6 men repeated the test by 10 times. And the results were that numerical average value was 124.44W and measurement uncertainty was $124.44W{\pm}0.75W$ with 95% confidence level for 125W PV module.

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Analysis of Solar Simulator's Uncertainty Factor for Maximum Output Power Test of Photovoltaic Module (PV모듈의 발전성능시험을 위한 Solar Simulator의 측정불확도 요인 분석)

  • Kang, Gi-Hwan;Kim, Kyung-Soo;Park, Chi-Hong;Yu, Gwon-Jong;Ahn, Hyung-Keun;Han, Deuk-Young
    • Journal of the Korean Solar Energy Society
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    • v.27 no.1
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    • pp.39-45
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    • 2007
  • In this paper, we analyzed the elements of measurement uncertainty on electrical performance test which are the most important things in photovoltaic module performance test. Repeating the performance test by 6 men, the measurement uncertainty could be calculated. In this experiment, Solar Simulator (A-Class pulse type) used for domestic certificate test of PV module is Pasan IIIb (Balval, Switzerland). The possible elements of the measurement uncertain that could effect electrical performance test of PV module are reference cell, spectrum correction, error from measurement repetition, test condition, stability and uniformity of artificial solar simulator. To find the measurement uncertainty, 6 men repeated the test by 10 times. And the results were that numerical average value was 124.44W and measurement uncertainty was $124.44W{\pm}0.36W$ with 95% confidence level for 125W PV module(KD-5125).

The Influence of Iteration and Subset on True X Method in F-18-FPCIT Brain Imaging (F-18-FPCIP 뇌 영상에서 True-X 재구성 기법을 기반으로 했을 때의 Iteration과 Subset의 영향)

  • Choi, Jae-Min;Kim, Kyung-Sik;NamGung, Chang-Kyeong;Nam, Ki-Pyo;Im, Ki-Cheon
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.1
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    • pp.122-126
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    • 2010
  • Purpose: F-18-FPCIT that shows strong familiarity with DAT located at a neural terminal site offers diagnostic information about DAT density state in the region of the striatum especially Parkinson's disease. In this study, we altered the iteration and subset and measured SUV${\pm}$SD and Contrasts from phantom images which set up to specific iteration and subset. So, we are going to suggest the appropriate range of the iteration and subset. Materials and Methods: This study has been performed with 10 normal volunteers who don't have any history of Parkinson's disease or cerebral disease and Flangeless Esser PET Phantom from Data Spectrum Corporation. $5.3{\pm}0.2$ mCi of F-18-FPCIT was injected to the normal group and PET Phantom was assembled by ACR PET Phantom Instructions and it's actual ratio between hot spheres and background was 2.35 to 1. Brain and Phantom images were acquired after 3 hours from the time of the injection and images were acquired for ten minutes. Basically, SIEMENS Bio graph 40 True-point was used and True-X method was applied for image reconstruction method. The iteration and Subset were set to 2 iterations, 8 subsets, 3 iterations, 16 subsets, 6 iterations, 16 subsets, 8 iterations, 16 subsets and 8 iterations, 21 subsets respectively. To measure SUVs on the brain images, ROIs were drawn on the right Putamen. Also, Coefficient of variance (CV) was calculated to indicate the uniformity at each iteration and subset combinations. On the phantom study, we measured the actual ratio between hot spheres and back ground at each combinations. Same size's ROIs were drawn on the same slide and location. Results: Mean SUVs were 10.60, 12.83, 13.87, 13.98 and 13.5 at each combination. The range of fluctuation by sets were 22.36%, 10.34%, 1.1%, and 4.8% respectively. The range of fluctuation of mean SUV was lowest between 6 iterations 16 subsets and 8 iterations 16 subsets. CV showed 9.07%, 11.46%, 13.56%, 14.91% and 19.47% respectively. This means that the numerical value of the iteration and subset gets higher the image's uniformity gets worse. The range of fluctuation of CV by sets were 2.39, 2.1, 1.35, and 4.56. The range of fluctuation of uniformity was lowest between 6 iterations, 16 subsets and 8 iterations, 16 subsets. In the contrast test, it showed 1.92:1, 2.12:1, 2.10:1, 2.13:1 and 2.11:1 at each iteration and subset combinations. A Setting of 8 iterations and 16 subsets reappeared most close ratio between hot spheres and background. Conclusion: Findings on this study, SUVs and uniformity might be calculated differently caused by variable reconstruction parameters like filter or FWHM. Mean SUV and uniformity showed the lowest range of fluctuation at 6 iterations 16 subsets and 8 iterations 16 subsets. Also, 8 iterations 16 subsets showed the nearest hot sphere to background ratio compared with others. But it can not be concluded that only 6 iterations 16 subsets and 8 iterations 16 subsets can make right images for the clinical diagnosis. There might be more factors that can make better images. For more exact clinical diagnosis through the quantitative analysis of DAT density in the region of striatum we need to secure healthy people's quantitative values.

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