• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.102-108
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• 2004

In this paper, we studied a vibration problem that is critical and common to most precision measurement systems. For micro mechanical part measurements, results obtained from the vision-based precision measurement system may contain errors due to the vibration. In order to defeat this generic problem, for the current study, a PC based image processing technique was used first, to assess the effect of the vibration to the precision measurement and second, to develop an in-situ calibration algorithm that automatically compensate the measurement results in real time. We used a set of stereoscopic CCD cameras to acquire the images for the dimensional measurement and the reference measurement. The mapping function was obtained through the in-situ calibration to compensate the measurement results and the statistical analysis for the actual results is provided in the paper. Based on the current statistical study, it is expected to obtain high precision results for the micro measurement systems.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.2
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• pp.158-165
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• 2018

Objectives: We analyzed the problems that work environment measurement results don't lead to workplace improvement in the Work Environment Measurement System to propose an alternative. Methods: We reviewed reports and articles written by the Korea Occupational Safety and Health Agency and academic circles to identify the problems in the current Work Environment Measurement System and suggest an alternative. Results: One of the reasons that the Work Environment Measurement has not resulted in workplace improvement is that there were no proper regulating systems for managing the workplace improvement plans or improvement results. Moreover, there are not enough professional manpower in ministry of labor to evaluate the improvement plans and results from the Work Environment Measurement. Therefore, all of the workplace whose Work Environment Measurement results exceed the occupational exposure limit (OEL) should be managed by regional ministry of labor, and outside experts and new system for verifying improvement are needed. Conclusions: To accomplish the purpose of Work Environment Measurement, it is necessary to improve the work environment according to the results of Work Environment Measure. For this, it is necessary for the government to manage the fulfillment of workplace improvement plans and for measurement agencies to secure expertise.

• Journal of Korean Society for Quality Management
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• v.51 no.3
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• pp.419-434
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• 2023

Purpose: Measurement results obtained under non-ideal measurement environment conditions may contain uncertain factors. As a result, the reliability of measurement results may be deteriorated. In this study, we tried to find ways to improve quality by evaluating and applying measurement uncertainty based on GUM. Methods: In the flatness measurement of semiconductor parts, uncertainty factors that could occur under actual environmental conditions of workers were derived, and measurement uncertainties were calculated, and methods for minimizing the main factors affecting the measurement results were analyzed. Results: Depending on the part and the coordinate measuring machine, it was shown that the effect of dispersion caused by repeated measurements as type A uncertainty and the effect of the calibration results of equipment as type B uncertainty have the main influence. Conclusion: Depending on the uncertainty factors of type A and type B and the influence of the total expanded uncertainty, the central value and confidence interval of the initial measurement results showed fluctuations. It is considered that analysis and measures for the main uncertainty factors are needed as quality improvement in the industrial field.

• Fashion & Textile Research Journal
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• v.21 no.5
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• pp.627-639
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• 2019

This study analyzes differences between the results of 3D direct measurements and automated measurements for Korean elderly females according to age groups, side somatotype, and BMI groups. This study compares the measurement differences of the direct and the 3D automated measurements for women between the ages of 70 to 85, according to age group, BMI group, and side somatotype. A comparison of the results of the direct measurement and the 3D automated measurements for elderly women show that a meaningful discrepancy exists for 29 items out of 33 items. Furthermore, the results of comparing the average error tolerance recommended by ISO20685 shows that 30 items out of 33 items exceeded ISO recommendations. The results of the automated measurement program shows a higher degree of accuracy for straight postures; however, this unsuitable for postures of elderly women with a changed somatotype. The analysis results of the measurement difference indicate the suitability of the automatic measurement programs is found to be high for stood postures, while problems seem to exist on several items along with an automated program is not appropriately used due to posture and part of body changes for elderly women. Therefore, it is recommended to develop an algorithm, that reflects the body changes of elderly women first and then upgrade the automated program equipped with a measurement size method. It is hoped that the study results can be utilized as base data for improving the automated measurement program.

• Journal of the Ergonomics Society of Korea
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• v.24 no.4
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• pp.7-13
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• 2005

We developed an accurate and reliable photogrammetric method available instead of the direct measurement method and the three-dimensional scanning method. Our research was restricted to a head on the body. Approaching three-dimensionally, we calibrated a distorted image of a photograph and got linear equations of camera beams. Then we assigned z values of landmarks in the head and obtained three-dimensional coordinates for each landmark putting those z values in linear equations of camera beams and finally could calculate measurement results from those three-dimensional coordinates. When we compared results obtained by a program, 'Venus Face Measurement(VFM)' that we had developed applying our method with results obtained by the direct measurement method, VFM showed very accurate and reliable results. In conclusion the photogrammetric method developed in this study was testified to an outstanding measurement method as a substitute for the direct measurement method and the three-dimensional scanning method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3550-3565
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• 2019

This paper proposes a new measurement method for the effective measurement of the 99% occupied bandwidth (OBW) at monitoring stations. Although the OBW measurement of radio signal is recommended by the International Telecommunication Union Radio (ITU-R) with several methods, there still does not exist a clear measurement recommendation or standard for terrestrial DTV signal on-air environment. Modified adjacent channel power ratio (MACPR), which can be applied to 8-VSB (Vestigial Side Band) DTV (Digital Television) signal, is herein defined to verify the results of measurements obtained using the proposed measurement method. MACPR is a proper measuring parameter for determining the measuring area of a monitoring station. From measurement results obtained in real field environment, it has been found that the OBW of 8-VSB DTV signal can be effectively measured in areas where the MACPR value is over 35 dB and when the measurements are repeated more than 600 times in the same reception site. It also has been verified that measured results are within an error range of +/-0.1% compared to results directly obtained at a transmission station. It is expected that the proposed method is able to be employed in order to determine the proper location of monitoring station and provide a reliable OBW measurement procedure for 8-VSB DTV signal on-air environment.

• International Journal of Contents
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• v.6 no.2
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• pp.6-9
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• 2010

Using symplectic relation and reaction concept, we propose a planar near-field antenna measurement method. A generalized probe compensation equation is deduced to obtain the probe correction formulation. To verify our approach, a reflector antenna with $1{\times}2$ horn array is fabricated and measured in the near-field measurement facility. The near-field measurement results are compared with the physical optics (PO) simulation. The results of measurement and simulation agree very well near to the mainbeam.

• Journal of the Korean Society of Costume
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• v.53 no.5
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• pp.1-12
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• 2003

This paper proposes a system for measuring the 3D human bodies using the multiple 2D images. The system establishes the multiple image input circumstance from the digital camera for image measurement. The algorithm considering perspective projection leads us to estimate the 3D human bodies from the multiple 2D images such as frontal. side and rear views. The results of the image measurement is compared those of the direct measurement and the 3D scanner for the total 40 items (12 heights, 15 widths and 13 depths). Three persons measure the 40 items using the three measurement methods. In comparison of the results obtained among the measurement methods and the persons, the results between the image measurement and the 3D scanner are very similar. However, the errors for the direct measurement are relatively larger than those between the image measurement and the 3D scanner. For example, the maximum errors between the image measurement and the 3D scanner are 0.41cm in height, 0.39cm in width and 0.95cm in depth. The errors are acceptable in body measurement. Performance of the image measurement is superior to the direct. because the algorithm estimates the 3D positions using the perspective projection. In above comparison, the image measurement is expected as a new method for measuring the 3D body, since it has the various advantages of the direct measurement and 3D scanner in performance for measurement as well as in the devices, cost, Portability and man power.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.2
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• pp.87-96
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• 2017

Objectives: Improvement of the reliability of work environment measurement results is one of the principal subjects to be resolved in the field of industrial hygiene. Thus, this study was conducted in order to review domestic programs for enhancing the reliability of work environment measurement results and propose a more efficient management plan for workplace monitoring. Materials and Methods: The current domestic programs reviewed in this study are the quality control system and evaluation system for industrial hygiene laboratories, the reliability system accompanied by KOSHA (the Korea Occupational Safety and Health Agency), the system of permissible exposure limits and observed inspection system for permissible exposure limits. Their contents and data were analyzed by reviewing articles, reports, and guidelines related to reliability improvement for work environment measurement results. Results: As a result of the literature review, all the domestic programs investigated in this study had both merits and demerits in terms of considering the reliability of work environment measurement results. In particular, the fact that preliminary notification is provided to the head of a workplace before implementation would be an obstacle for elevating the reliability of work environment measurement results. Conclusions: Based on the review results obtained from this study, it is proposed that on-site measurement without preliminary notification should be considered for a more efficient inspection system that would enhance the reliability of workplace monitoring.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.173-178
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• 2016

Background: In situ gamma spectrometry has been used to measure environmental radiation, assumptions are usually made about the depth distribution of the radionuclides of interest in the soil. The main limitation of in situ gamma spectrometry lies in determining the depth distribution of radionuclides. The objective of this study is to develop a method for subsurface characterization by in situ measurement. Materials and Methods: The peak to valley method based on the ratio of counting rate between the photoelectric peak and Compton region was applied to identify the depth distribution. The peak to valley method could be applied to establish the relation between the spectrally derived coefficients (Q) with relaxation mass per unit area (${\beta}$) for various depth distribution in soil. The in situ measurement results were verified by MCNP simulation and calculated correlation equation. In order to compare the depth distributions and contamination levels in decommissioning KRR site, in situ measurement and sampling results were compared. Results and Discussion: The in situ measurement results and MCNP simulation results show a good correlation for laboratory measurement. The simulation relationship between Q and source burial for the source layers have exponential relationship for a variety depth distributions. We applied the peak to valley method to contaminated decommissioning KRR site to determine a depth distribution and initial activity without sampling. The observed results has a good correlation, relative error between in situ measurement with sampling result is around 7% for depth distribution and 4% for initial activity. Conclusion: In this study, the vertical activity distribution and initial activity of $^{137}Cs$ could be identifying directly through in situ measurement. Therefore, the peak to valley method demonstrated good potential for assessment of the residual radioactivity for site remediation in decommissioning and contaminated site.