• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.863-869
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• 2007

An improved method based on a normal frequency response function (FRF) is proposed to identify structural parameters such as mass, stiffness and damping matrices directly from the FRFs of a linear mechanical system. The method for estimating structural parameters directly from the measured FRFs of a structure is presented. This paper demonstrates that the characteristic matrices are extracted more accurately by using a weighted equation and eliminating the matrix inverse operation. The method is verified for a four degree-of-freedom lumped parameter system and an eight degree-of-freedom finite element beam. Experimental verification is also performed for a free-free steel beam whose size and physical properties are the same as those of the finite element beam. The results show that the structural parameters, especially the damping matrix, can be estimated more accurately by the proposed method.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.2
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• pp.127-132
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• 2005

The optical glass lens is required high dimensional precision such as the lack of defect. In this paper, we examined the detectable defect by using the resonant ultrasound spectroscopy(RUS). The RUS is the measurement system which is to excite the specimen and to inspect the differences of resonant frequency pattern between acceptable specimen and specimen which has some defects. In this paper, for nondestructive evaluation by using RUS, we measured the resonant frequency of each specimen which is spherical and aspherical glass lens. With the results, we knew the polishing processing degree of spherical glass lens by the measured resonant frequency and could evaluate the characteristic of aspherical glass lens about some flaws.

• Journal of Drive and Control
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• v.15 no.4
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• pp.1-10
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• 2018

Spool displacement of a direction control valve is the standard signal to measure the bandwidth frequency of the direction control valve. When the spool displacement signal is not available, it is suggested in this study to use the metering hydraulic line as an alternative way to measure - 90 degree phase bandwidth frequency of the hydraulic direction control valve. Dynamics of the hydraulic line is composed of inertia, capacitance, and friction effects. The effect of oil inertia is dominant in common hydraulic line dynamics and the line dynamics is close to a derivative action in a range of high frequency; such as a range of bandwidth frequency of common directional control valves. Phase difference between spool displacement and line load pressure is nearly constant as a valve close to 90 degree. If phase difference is compensated from the phase between valve input and pressure, compensated phase may be almost same as the phase of spool displacement that is a standard signal to measure phase bandwidth frequency of the directional control valve. A series of experiments were conducted to examine the possibility of using line pressure in to measure phase bandwidth frequency of a directional control valve. Phase bandwidth frequency could be measured with relatively high precision based on metering hydraulic line technique and it reveals consistent results even when valve input, oil temperature, and supply pressure change.

• The Korean Journal of Emergency Medical Services
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• v.12 no.2
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• pp.5-26
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• 2008

Purpose : This study was performed to develop the curriculum of Emergency Medical technology of College. Method : The authors analyzed curricular of EMT in 12 college in Korea. We conducted the distribution, credit, mean, frequency of liberal arts, majors, teaching profession subject by Kim and Lee(2007). We compared curriculum of knowledge and clinical training courses. Results : The numbers of whole subjects were 59.3 and the number of mean and the credits were 130.8 degree of mean. The numbers of liberal arts were 9.5 number of mean and the credits were 15.5 degree of mean. The numbers of major were 47.5 number of mean and the credits were 111.4 degree of mean. The numbers of teaching profession subject were 1.9 number of mean and the credits were 4 degree of mean. Finally, frequency of curriculum of knowledge and clinical training courses were 57.1% and 42%, respectively. Conclusion : This results will represent curriculum development and will standardize curriculum for EMT collage. in addition, it will make EMT curriculum standardized.

• Journal of Korean society of Dental Hygiene
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• v.6 no.2
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• pp.153-164
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• 2006

Purpose: The purpose of this study was to analyze level of dental health knowledge and behavior of mothers, health educators should encourage mother to have continuous dental care habits for lifelong dental health with practical education. Methods: The subjects in this study were 490 mothers of four-year, fifth-year and sixth-year from elementary school in Daegu areas. The data was collected through a structured questionnaire from 26, June to 27, June 2006. Collected data were analyzed into frequency and Chi-square test using SPSS 10.0 program. Result: First, no statistically significant relations were found between mothers, knowledge with general characteristics of subject(age, degree of education, yes or no of occupation, subjective economy). Second, mothers, number of toothbrushing were statistically significant relations with degree of education, yes or no of occupation as over three times a day. Third, no statistically significant relations were between visiting frequency of dental clinic for one years with general characteristics of subject(age, degree of education, yes or no of occupation, subjective economy). Fourth, yes or no of use in auxiliary oral hygiene device were statistically significant relations with degree of education, yes or no of occupation, subjective economy. Fifth, mothers, knowledge were statistically significant relations with auxiliary oral hygiene device.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4604-4613
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• 2010

The purpose of this study is to survey the outdoor living space of apartment housing complexes in Daejeon area and to find out the degree of satisfaction, the frequency of use, the preference of facilities and the degree of importance. This study insists that the recognition about the residents' changing demands and interests be considered more important than the aesthetic design. Moreover, it can be proposed as the basic resource which can be used for the social demands. Therefore, various perspectives about the outdoor living space of apartment housing complexes can play an vital role in improving the design process and developing better residential environment.

• Korean Journal of Human Ecology
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• v.9 no.2
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• pp.189-203
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• 2000

This study was proposed preschooler consumer education curriculum to give effect at a preschooler education institute and was investigated into relations with practical degree, needful degree and demandable degree according to preschooler teacher's characteristics. The survey of this research was conducted by means of questionnaire with 548 teachers of nursery and kindergarten in Seoul. Also it was carried out two stages cluster sampling, personal interview. the statistics used for data analysis was frequency, mean, percentile, t-test, one way ANOVA, Pearson's r, and regression using the SPSS/PC+ program. The results and findings of this study were summarized as follows. 1) Practical degree on total preschooler consumer education was looked into being low, also needful degree on total preschooler consumer education examined being very high. 2) Demandable degree on preschooler consumer education differed significantly according to preschooler education institute, preschooler's age in charge. 3) Practical degree on preschooler consumer education correlated positively to needful degree on preschooler consumer education. And practical degree on preschooler consumer education correlated negatively to demandable degree on preschooler consumer education. 4) Preschooler teacher's age and career had affected to money management in practical degree by regression analysis used to dummy variable related with characteristics of preschooler teacher.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.891-897
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• 2013

The power system frequency plays an important role in monitoring and controlling the power system. The frequency can be measured through discrete Fourier transform (DFT) coefficients of its positive fundamental frequency. The accuracy of the frequency estimate is severely affected by noise in the power system signal and the leakage effect of the negative fundamental frequency in DFT. This paper proposes a DFT-based frequency estimation algorithm to cope with the noise as well as the leakage effect. In this algorithm, two suitable digital filters are introduced to reduce efficiently frequency estimate error due to the noise. These filters are designed to use a digital bandpass filter and a second-degree integrator. The effectiveness of the proposed algorithm in reduction of frequency estimate error is verified through simulations on noise, harmonics and frequency deviation.

• Journal of Fashion Business
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• v.10 no.4
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• pp.130-139
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• 2006

This study was conducted to survey and analyze the preference, and acceptance of smart clothing to the consumers with different age. A questionnaire with the objects of 530 consumers from the teens to the forties, in order to utilize the characteristics of consumers as basic materials for the planning of smart clothing, which is reasonably designed to have both of function and fashion, by checking the characteristics of consumers. The results are as follows; 1. The interest degree of fashion was the highest in the 20's and the acceptance degree showed the medial frequency in all age groups. In terms of the analysis result regarding general persons and professionals, professionals showed higher frequency distribution in both interest degree and acceptance degree than general persons. 2. When a comparison for each age, general person, and professional was made, more than the majority of all could not recognize the terms and concept about the smart clothing, but in terms of the favorable impression, more than the majority answered that it interests them. 3. More than the majority of the objects of this survey responded that they have a purchase intention and in terms of the desired purchase price, the price below 500,000 won showed the most frequency. In terms of the reason of wearing the smart clothing, they responded that they can select needed functions, and in terms of an occurring problem, they answered that it is the high cost of economic burdens.

• Korean Institute of Interior Design Journal
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• v.21 no.1
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• pp.95-102
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• 2012

This study analyzed the observation characteristics with the subject of observation data through defining the change of the observation degree as attention /conscious observation /visual understanding. Furthermore, by obtaining the formular with which to estimate the subjects' observation amount, this study suggests a potential method for easier analysis of observation characteristics. The conclusions from the study are as the followings. First, the observation frequency was being generated with wide deviation among subjects while there was a flow-on characteristics depending on the degree of observation. These characteristics enabled the study to obtain the formular with which to estimate the observation amount. Second, the study could establish the area frequency by grade from the entire observation data. The area I was at most 4% for the area frequency but accounted for 18.2% of the entire effective observation time, and the area II 16% and 38.7% respectively. Accordingly, only considering the observation area distribution of the area I or the areas I and II shows which position of the space the subjects were observing. Third, with the subject of the relatively higher observation time at at the subject's observation characteristics, as the observation phase was getting higher, the observation time decreased more. Forth, by obtaining the formular to estimate the observation amount for observation data according to the change of observation degree, the study could find the estimating observation characteristics of additional subjects. The formular shortens the analysis time and facilitates the analysis process.