• Korean Journal of Digital Imaging in Medicine
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• v.11 no.2
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• pp.59-62
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• 2009

The purpose of this study is to know about solution of insecurity sense for solving the tediousness and inducing comfortableness in long time MRI examination. Studies were examined with total of 117 patients that the intention expression of self is possible for a month without dividing man and woman in november 2006. Examination methods were filled in questionnaire after testing using Siemens Impact 1.0T. The musical art were selected through intranet search and record sale inquiry using CD player and speaker. That kind of a music were selected with Korean classical music's 10 chapter, pop song 10's chapter, classic's 10 chapter and Korean popular song's 10 chapter. With analytical method, patients of under 40 year-old, or older and patients using ear-pad and head-phone were classified into groups. As analysis result with question item of questionnaire, most of the patients were showed a favor(36.72%) in playing a music, specially, examination of about 15.38% which uses the headphone prefer a music as older generation of over 40 year-old. In conclusion, with installing of the professional musical program in MRI test rooms, if listening to the music with selection by oneself before testing by season, age, time through development of appropriate musical program will be able to expect the more effect.

• Science of Emotion and Sensibility
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• v.8 no.1
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• pp.9-15
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• 2005

Because hand-written characters, especially drawn by a brush can give readers various impressions, they are not only a communication method but also art works. Authors have already investigated the relationship between brush motion analytical results and sensory testing results obtained from Japanese hiragana and reported quantitative evaluation method for the beauty of hiragana, In this paper, sensory tests for South Koreans who cannot recognize the word are carried out, compared with sensory testing results of Japanese. The evaluation objects are 6 hiragana drawn by 4 beginners and 2 experts, Semantic Differential Method based on 30 paired evaluation words are used in the sensory tests. Therefore South Koreans also feel the beauty in hiragana drawn by experts, as compared with by beginners. On the other hand it was confirmed that South Koreans couldnt recognize the difference among beginners. Judging from the factor analysis results, both Japanese and South Koreans selected stability as the 1st factor, there is interesting difference in the following orders.

• Nuclear Engineering and Technology
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• v.43 no.6
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• pp.573-582
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• 2011

The in-cabinet response spectrum is used to define the input motion in the seismic qualification of instruments and devices mounted inside an electrical cabinet. This paper presents a procedure for generating the in-cabinet response spectrum for electrical equipment based on in-situ testing by an impact hammer. The proposed procedure includes an algorithm to build the relationship between the impact forces and the measured acceleration responses of cabinet structures by estimating the state-space model. This model is used to predict seismic responses to the equivalent earthquake forces. Three types of structural model are analyzed for numerical verification of the proposed method. A comparison of predicted and simulated response spectra shows good convergence, demonstrating the potential of the proposed method to predict the response spectra for real cabinet structures using vibration tests. The presented procedure eliminates the uncertainty associated with constructing an analytical model of the electrical cabinet, which has complex mass distribution and stiffness.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.3
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• pp.261-270
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• 2010

This paper presents an analytical investigation for a baseline-free imaging of a defect in plate-like structures using the time-reversal of Lamb waves. We first consider the flexural wave (A0 mode) propagation in a plate containing a defect, and reception and time reversal process of the output signal at the receiver. The received output signal is then composed of two parts: a directly propagated wave and a scattered wave from the defect. The time reversal of these waves recovers the original input signal, and produces two additional side bands that contain the time-of-flight information on the defect location. One of the side band signals is then extracted as a pure defect signal. A defect localization image is then constructed from a beamforming technique based on the time-frequency analysis of the side band signal for each transducer pair in a network of sensors. The simulation results show that the proposed scheme enables the accurate, baseline-free detection of a defect, so that experimental studies are needed to verify the proposed method and to be applied to real structure.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.6
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• pp.457-466
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• 2014

This paper presents an analytic and numerical simulation of the generation and propagation of pico-second ultrasound with nano-scale wavelength, enabling the production of bulk waves in thin films. An analytic model of laser-matter interaction and elasto-dynamic wave propagation is introduced to calculate the elastic strain pulse in microstructures. The model includes the laser-pulse absorption on the material surface, heat transfer from a photon to the elastic energy of a phonon, and acoustic wave propagation to formulate the governing equations of ultra-short ultrasound. The excitation and propagation of acoustic pulses produced by ultra-short laser pulses are numerically simulated for an aluminum substrate using the finite-difference method and compared with the analytical solution. Furthermore, Fourier analysis was performed to investigate the frequency spectrum of the simulated elastic wave pulse. It is concluded that a pico-second bulk wave with a very high frequency of up to hundreds of gigahertz is successfully generated in metals using a 100-fs laser pulse and that it can be propagated in the direction of thickness for thickness less than 100 nm.

• Smart Structures and Systems
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• v.10 no.2
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• pp.131-154
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• 2012

In this paper, it is aimed to determine the seismic behaviour of highway bridges by nondestructive testing using ambient vibration measurements. Eynel Highway Bridge which has arch type structural system with a total length of 216 m and located in the Ayvaclk county of Samsun, Turkey is selected as an application. The bridge connects the villages which are separated with Suat U$\breve{g}$urlu Dam Lake. A three dimensional finite element model is first established for a highway bridge using project drawings and an analytical modal analysis is then performed to generate natural frequencies and mode shapes in the three orthogonal directions. The ambient vibration measurements are carried out on the bridge deck under natural excitation such as traffic, human walking and wind loads using Operational Modal Analysis. Sensitive seismic accelerometers are used to collect signals obtained from the experimental tests. To obtain experimental dynamic characteristics, two output-only system identification techniques are employed namely, Enhanced Frequency Domain Decomposition technique in the frequency domain and Stochastic Subspace Identification technique in time domain. Analytical and experimental dynamic characteristic are compared with each other and finite element model of the bridge is updated by changing of boundary conditions to reduce the differences between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of highway bridges. After finite element model updating, maximum differences between the natural frequencies are reduced averagely from 23% to 3%. The updated finite element model reflects the dynamic characteristics of the bridge better, and it can be used to predict the dynamic response under complex external forces. It is also helpful for further damage identification and health condition monitoring. Analytical model of the bridge before and after model updating is analyzed using 1992 Erzincan earthquake record to determine the seismic behaviour. It can be seen from the analysis results that displacements increase by the height of bridge columns and along to middle point of the deck and main arches. Bending moments have an increasing trend along to first and last 50 m and have a decreasing trend long to the middle of the main arches.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.4 s.56
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• pp.180-187
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• 2009

The objective of this research is to verify the code-specified girder distribution factors (GDF) for continuous steel girder bridges by field testing. Previous analytical study revealed that current GDF's specified in AASHTO Standard and AASHTO LRFD, developed for the simple span bridges are conservative even for the continuous bridges. In this study, field tests were performed for three continuous steel girder bridges to validate the GDF's specified in the AASHTO codes. The results show that the code values are conservative when compared with field tests, and in some cases, too conservative. Also, strains measured from the field test are, in most cases, smaller than those expected from the analytical results. However, when the GDF's from measured strains are compared with GDF's from analysis, it is found that the analysis results are not conservative, and in some instance, the analytical results underestimate the actual GDF's, which can lead to a groundless notion of safety. In one case, test results showed that the code GDF's specified in AASHTO LRFD is too permissive. As a result, it is found that GDF's specified in AASHTO LRFD should be used with careful reservation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.313-321
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• 1996

Our laboratoy has been participated in Proficiency Analytical Testing (PAT) program which is operated by the Americal Industrial Hygiene Association in cooperation with the National Institute for Occupational Safety and Health (NIOSH). The program is designed to assist a laboratory improve its analytical performance by providing samples on a quarterly basis, evaluating the results, and providing reports on how well the laboratory performed. Evaluation of the results reported here covers five rounds of the PAT program (round 121~round 125). The way a laboratory is evaluated by PAT program is as follows: 1) There is no overall proficiency rating given to a laboratory. 2) A proficiency rating is given for each type of analyze (i.e., metals, silica, asbestos, solvents) that a laboratory analyzed. 3) Proficiency is rated acceptable ("A") if Z score lies between -3 and +3, and unacceptable if Z score is either higher than +3 ("H") or lower than -3 ("Lo"). Z score = (reported data - reference value) / standard deviation 4) For a laboratory to be rated proficient it must either have had no outliers over the most recent two rounds or of the samples actually analyzed over the past year (past four rounds), 75 % or more of the analyze sample results must be acceptable. According to the above rating criteria of PAT program, performance of metals including cadmium, lead, chromium and zinc, and asbestos sample analyses were rated acceptable ("A"). For silica analyses, all samples except one out of four samples in round 122 was rated high("H") were acceptable showing 95 % of ing 95 % of acceptance rate (19/20) throughout the rounds. Analyses of organic solvents were done on 52 samples in 9 types including methanol(MOH), 1,1,1-trichloroethane(MCM), tetrachloroethylene(PCE), trichloroethylene(TCE), benzene(BNZ), o-xylene(OXY), toluene(TOL), chloroform(CFM), 1,2-dichloroethane(DCE). All samples analyzed were rated acceptable except 2 samples that were rated high; one out of each four MCM and TCE samples in round 121, and one that was low out of four o-xylene analyses in round 122 indicating 94 % of acceptance rate(49/52) throughout the rounds. According to the laboratory rating criteria, our laboratory is rated proficient so far for all types of contaminants.

• Analytical Science and Technology
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• v.23 no.2
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• pp.138-146
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• 2010

The Korean Ministry of the Environment revised a few sections of the regulations in the Law of indoor air quality management for the reinforcement or adjustment of the regulation criteria standard for releasing pollutants from building materials. Especially, in case of sealant, the contents covering liquid building materials, excess standards and testing methods have been added simultaneously in this revision, As a result it is impossible to compare original standards with revised standards directly. For this reason, this study reviewed revised test method of sealant pollutant emission rates in terms of impact and validity in comparison with the original test method. Through this study, the basic properties of revised pollutant emission control standards was assessed. Especially in sealant, since each product has a wide deviation of time required for complete drying, it is proved that there are a large number of products that are not hardened completely in test time. The result of our experiments on the revised test methods showed that this revised test methods yield emission rates that are two and half times less than those of the original testing method. To apply the revised test method of sealant to all the sealant products, It is necessary to extend the test period or improve specimen to fit the test method for quickly drying sealant products.

• Analytical Science and Technology
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• v.20 no.5
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• pp.393-399
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• 2007

In principle, the blood galactose level may be determined conveniently with a strip-type biosensor similar to that for glucose. In this study, we describe the development of a disposable galactose biosensor strip for point-of-care testing. The sensor strip is constructed with screen-printed carbon paste electrode (SPCE) and sample amount (< $100{\mu}L$). The developed strip the galactose level in less than 90 s using bienzymatic system of galactose oxidase (GAO) and horseradish peroxidase (HRP). The effects of pH, mediator (1,1-ferrocenedimethanol) concentration, ratio of enzymes, and applied potential were determined preliminarily with glassy carbon electrodes, and optimized further with the strip-type electrodes. The sensor exhibits linear response in the range of $0{\sim}400{\mu}M$ ($r^2$ = 0.997, S/N = 3). Since a low working potential, in principle, the fabricated disposable galactose biosensor has -100 mV (vs. Ag/AgCl), it is applied for the detection of galactose, interfering responses from common interferents such as ascorbic acid, uric acid and acetaminophen could be minimized. The sensor has been used to determine the total galactose level in standard samples with satisfactory reproducibility (CV = 5 %).