• Journal of the Optical Society of Korea
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• v.7 no.3
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• pp.174-179
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• 2003

We construct a four-level system where a metastable state is included in an $Er^{3＋}$ Doped Yttrium aluminum garnet (YAG) crystal. Because of the action of the coherent field, the traditional light amplification with inversion can be exhibited with remarkable variation. As a result, we propose a method to achieve the gain equalization by atomic coherence. At the same time, we find that the high index of refraction accompanied by vanishing absorption can also be reached in this model. We also find that a higher index of refraction with zero absorption can be easily obtained when the coherent field is off resonance.

• Journal of the Korean Home Economics Association
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• v.40 no.2
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• pp.67-86
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• 2002

The purpose of this research is to offer a method to derive the body shapes and pose factors with resets from analyzing factors by using the measurement values of human body. 297 male subjects in their twenties participated in this study. 54 anthropometric and 35 photographic measurements were taken from each subject. Data is the several typical items selected among items and you have to make an index value by using these typical items and convert it. The index has high correlation with each item, is easy to be measured and is to be used after selecting an important item in designing prototype. With results of analyzing reliability level by each item, correlation and items that factor loading is low, the item that the correlation is high is to be removed within the range that maintains the reliability level. Five factors of the front part and seven factors of the profile came to be derived from this kind of process.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.273-278
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• 2002

Booming sound is one of the most important interior sound of a passenger car. The conventional booming noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level can not give the whole story about the booming sound of a passenger car. In this paper, we employed sound metric which is the subjective parameter used in psycoacoustics. According to recent research results, the relation between sound metrics and subjective evaluation is very complex and has nonlinear characteristics. In order to estimate this nonlinear relationship, artificial neural network theory has been applied to derivation of sound quality index for booming sound of a passenger car.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.48-54
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• 2002

This research estimated decreased vibration level as quantitative according to change of track system on Seoul Subway Line No. 1 from existing ballasted track system(Pandrol type clip) to concrete track system(Youbgdan type isolation rubber clip). Following change to concrete system, vibration level at tunnel floor decreased between 4-8dB(V). Vibration equations suggested in this paper consider the velocity of train and can estimate quantitative vibration response. These are divided by ultimate limit state($\beta$=0), serviceability limit state($\beta$=1.28) and safety state($\beta$=3), respectively. The reliability index, $\beta$=0, means 50％ data line obtained by least squares best-fit line. The reliability index $\beta$=1.28 and 3 represent boundaries below 90％ and 99.9％ respectively.

• ETRI Journal
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• v.38 no.2
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• pp.405-415
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• 2016

This research proposes the use of a patent analysis methodology that can suggest promising technology in the ICT sector at the micro-level. This approach identifies core patents from the technology field, groups them as research frontiers (RFs), and develops a visualized network based on the citing relationships to monitor the relationship among RFs. In addition, it calculates a "promising index" based on the growth potential, impact, and marketability of patents to ultimately derive promising RFs. To illustrate the proposed approach, this research presents analysis results for a chosen area, which is the user interface and user experience (UI/UX) technology field. By proposing promising technological fields at the micro-level, the proposed methodology will serve as a useful decision-making support tool in selecting R&D projects, technology planning, and determining technology policy direction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.997-1002
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• 2004

Rumbling sound is one of the most important interior sound of a passenger car. The conventional rumbling noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level can not give the whole story about the rumbling sound of a passenger car. In this paper, we employed sound metric which is the subjective parameter used in psycoacoustics. According to recent research results, the relation between sound metrics and subjective evaluation is very complex and has nonlinear characteristics. In order to estimate this nonlinear relationship, artificial neural network theory has been applied to derivation of sound quality index for rumbling sound of a passenger car.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.628-634
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• 2003

Rumbling sound is one of the most important interior sound of a passenger cu. The conventional rumbling noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level can not give the whole story about the rumbling sound of a passenger car. In this paper, we employed sound metric which is the subjective parameter used in psycoacoustics. According to recent research results, the relation between sound metrics and subjective evaluation is very complex and has nonlinear characteristics. In order to estimate this nonlinear relationship, artificial neural network th[ ory has been applied to derivation of sound quality index fur rumbling sound of a passenger car.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.6
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• pp.445-451
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• 2003

Booming sound is one of the most important interior sound of a passenger car. The conventional booming noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level cannot give the whole story about the booming sound of a passenger car. In this paper, we employed sound metrics, which are the subjective parameters, used in psycoacoustics. According to recent research results. the relation between sound metrics and subjective evaluation is very complex and has nonlinear characteristics. In order to estimate this nonlinear relationship, artificial neural network theory has been applied to derivation of sound quality index for booming sound of a passenger car.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.4
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• pp.83-90
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• 2018

Purpose : This study aims to examine the correlation between SPQ (sasang personality questionnaire) results and the significance level of general mental and physical health among youths. Effects of physical factors on the level of health are also examined. Methods : For the purpose of this study, the SPQ test and body mass and the Ponderal index were measured. The SPQ was followed by a survey on physical changes among 686 young people. The correlation between SPQ and BMI was analysed using Pearson's corelation. Post hoc tests were conducted on SPQ sub factors (SPQ-B, SPQ-C, and SPQ-E) were examined. Results : The findings from the analysis of the high, middle and lower group profiles of adolescent SPQ-B, SPQ-C, and SPQ-E showed that the three groups had significant results. This study demonstrates the correlations among sub factors of the SPQ. No correlation was observed regarding physical characteristics. Conclusion : This study demonstrates the correlations among sub factors of the SPQ. No correlation was observed regarding physical characteristics.

• Journal of Industrial Convergence
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• v.1 no.2
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• pp.17-31
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• 2003

Many risk factors with the onset of Low Back Pain(LBP) have been identified, however, lifting out of Manual Material Handling(MMH) was the most important factor to the LBP. Injuries due to lifting took account for 34.0%(227,291) out of the total overexertion in MMH(668,084). The weight, vertical location, twist angle, lifting frequency, and lifting posture were reviewed in this study. Technical information for using the revised lifting equation to evaluate a variety of two - handled manual material handling tasks was suggested. To measure worker's fatigue in lifting task, Lifting Index Simulator(LIS) was create under the revised NIOSH(National Institute for Occupational Safety and Health) lifting equation. For the implementation of the LIS, data was collected in A company manufactures various paints in Si-Wha industrial complex, Kyunggi-Do. The results of the Lifting Index(LI) were analyzed by MANOVA to find the relation with lifting variables collected. It was found that horizontal distance, vertical distance, travelling distance and frequency were significant at the 0.01 level and weight was significant at the 0.05 level. The purpose of this paper is to reduce the chronical low back pain for the manual material handlers.