• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.1
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• pp.17-24
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• 2013

The process of producing high precision and light weight product is always exposed to impact load or shock. Because of this, isolator device is required. To measure the response of the isolator, accelerometer is practically used. However, the measured response of the accelerometer is different to the response of the isolator. To predict the response of the accelerometer and the isolator, 2-DOF damped system with an input shock is modeled using numerical analysis. 1-DOF damped system with a base excitation is also used to predict the response of the isolator. The mass ratio, damping ratio, and natural frequency ratio are then varied. The predicted responses from the two modeling approaches are compared and large errors are found.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1044-1049
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• 2006

The vibration exciter with the accurate calibration requires a low distortion along a single axis over a wide range of frequency. The fabricated piezoelectric exciter was composed of a base, piezoelectric element(Venitron PZT 5A), electrode and seismic mass. Its performance characteristics is evaluated the Mach-Zehnder optical fiber interferometer. The phase of the optical wave passing through the optical fiber around the piezoelectric element was related the vibrational amplitude with a change of the applied sinusoidal voltage on the piezoelectric element. The dynamic characteristics of vibration exciter can be obtained by measuring the vibrational amplitude with a sinusoidal applied voltage on the piezoelectric element. The sensitivity of the fabricated piezoelectric exciter had a 0.4 nm/V which was uniform up to 20 kHz.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.983-989
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• 2013

This study proposes a piezoelectric vibration energy harvester composed of two diagonally segmented energy harvesting units. An auxiliary structural unit is attached to the tip of a host structural unit cantilevered to a vibrating base, where the two components have beam axes in opposite directions from each other and matched short-circuit resonant frequencies. Contrary to the usual observations in two resonant frequency-matched structures, the proposed structure shows little eigenfrequency separation and yields a mode sequence change between the first two modes. These lead to maximum power generation around a specific frequency. By using commercial finite element software, it is shown that the magnitude of the output power from the proposed vibration energy harvester can be substantially improved in comparison with those from conventional cantilevered energy harvesters with the same footprint area and magnitude of a tip mass.

• Journal of the Korean Society of Radiology
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• v.2 no.2
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• pp.11-16
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• 2008

The most difficult of implementation PACS is large amount of data. Therefore, PACS needs mass storage, as well as rapid transmission time. Consequently, medical images needs compression when stored in PACS. WT(wavelet transform) was announced by Ingrid Daubechies and Stephane Mallat, WT was methods of signal analysis by a base functions set same as Fourie transform. This paper estimated an efficiency, that experimental medical images compressed by DWT. The result of estimated, we are knows effectiveness that display to remained signal in low frequency region after 4-level DWT form $512{\times}512{\times}2^8$ input images. Compression ratio of images by 4-level DWT was 1:16. It is a high compression ratio, the other side has a problem appears on staircase phenomenon.

• Journal of Fashion Business
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• v.12 no.4
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• pp.158-169
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• 2008

This study aims to survey the perceptions held by students and field workers regarding the clothing-related qualification certificates, which can serve as the base for becoming clothing professionals, to compare and analyze the actual state of qualification certificates on the basic research level, and thus to search for the directions suitable for the clothing-related qualification certificates. The questionnaire method was selected for the study. The responses of 406 copies from students and 81 copies from field workers were used, and frequency analysis and t-test were done with the assistance of spss 10.0 statistics program, The findings are as follows. First, as to the qualification certificates perceived by the students, the certificates of colorist engineer and colorist industrial engineer were known most. 237 students, or 58.4% of the student respondents, had obtained the information about the qualification certificates mainly through the internet and mass media, and 77.3% of the students had a plan to get the qualification certificates. Second, as to the qualification certificates perceived by the field workers, the respondents indicated that school grades(43.2%) would be given the highest additional points at the time of employment, while the clothing-related qualification certificates gathered low responses of 11.1%. The field workers perceived that the qualification certificate of Western suit engineer(pattern) was needed for the job, while 45.4% of them perceived that no qualification certificate was required for the job. Third, both the students and the field workers showed low acquisition levels of the qualification certificates, and in view of their perceptions that the qualification certificates of languages or computer skills were more useful, the improvement is needed in order for the national certificates for the clothing-related skill qualification to develop in the more job-related directions.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.508-508
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• 1996

;The growth of films have considerable interest in the field of superlattice structured multi-layer epitaxy led to realization of new devices concepts. Molecular beam epitaxy (MBE) with in situ observation by reflection high-energy electron diffraction (RHEED) is a key technology for controlled layered growth on the atomic scale in oxide crystal thin films. Also, the combination of radical oxygen source and MBE will certainly accelerate the progress of applications of oxides. In this study, the growth process of single crystal films using by MBE method is discussed taking the oxide materials of Bi-Sr-Ca-Cu family. Oxidation was provided by a flux density of activated oxygen (oxygen radicals) from an rf-excited discharge. Generation of oxygen radicals is obtained in a specially designed radical sources with different types (coil and electrode types). Molecular oxygen was introduced into a quartz tube through a variable leak valve with mass flowmeter. Corresponding to the oxygen flow rate, the pressure of the system ranged from $1{\;}{\times}{\;}10^{-6}{\;}Torr{\;}to{\;}5{\;}{\times}{\;}10^{-5}$ Torr. The base pressure was $1{\;}{\times}{\;}10^{-10}$ Torr. The growth of Bi-oxides was achieved by coevaporation of metal elements and oxygen. In this way a Bi-oxide multilayer structure was prepared on a basal-plane MgO or $SrTiO_3$ substrate. The grown films compiled using RHEED patterns during and after the growth. Futher, the exact observation of oxygen radicals with MBE is an important technology for a approach of growth conditions on stoichiometry and perfection on the atomic scale in oxide. The oxidization degree, which is determined and controlled by the number of activated oxygen when using radical sources of two types, are utilized by voltage locked loop (VLL) method. Coil type is suitable for oxygen radical source than electrode type. The relationship between the flux of oxygen radical and the rf power or oxygen partial pressure estimated. The flux of radicals increases as the rf power increases, and indicates to the frequency change having the the value of about $2{\times}10^{14}{\;}atoms{\;}{\cdots}{\;}cm^{-2}{\;}{\cdots}{\;}S^{-I}$ when the oxygen flow rate of 2.0 seem and rf power 150 W.150 W.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.89-97
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• 1998

This study is intended to investigate the seismic responses of bridge structures considering site effects. The site effects in the seismic analysis of bridge structures were classified into two parts. At first, the seismic responses of the structures on each "soil profile types" of the code were evaluated in accordance with code-specified method and compared with results of time-history analysis method. And next, as a second stage of the study, the responses of the two different soil with considerably different soil properties, even though they are classified to the same "soil profile types" of the code, were evaluated and compared each other. The first part of study is purposed to evaluate the applicability of code-specified method, while the other part is purposed to find the variance of the seismic responses from the different soil sites in the same soil profile types of the code. For the analysis, two major methods of the code, single-mode spectral anaysis and multi-mode spectral analysis, were used and the time-history analysis method which is expected to give more accurate responses was also used for the comparison purposes. For the time-history analysis, time-domain analysis technique of the lumped-mass model with frequency-independent soil springs and dampers was adopted and artificially generated spectra of the code was used as input motion. As the results of the study, the code specified methods for the seismic responses considering the site effects were verified to give the results in conservative side for the most of the cases. However, for the structures on the site with considerable flexibility, the responses of the bridge girders or deckplates by the code methods both in section forces and horizontal movement responses, may have much smaller values than the actual responses. Therefore, more detailed analysis considering the flexibility of the base soil may be required to have more reasonable results in girder responses.in girder responses.

• Journal of Life Science
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• v.19 no.5
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• pp.664-670
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• 2009

The ${\beta}$3-adrenergic receptor (ADRB3) is expressed mainly in visceral adipose tissue and is thought to contribute to lipolysis and the delivery of free fatty acids to the portal vein. This study was aimed at evaluating the association between high-density lipoprotein cholesterol (HDL-C) and ADRB3 genetic polymophisms. A total of 991 healthy examinees who were examined in a university hospital, located in Busan City, between May and December 2006 were enrolled in this study. Height, weight, body mass index, waist circumference, and systolic and diastolic blood pressures of the subjects were examined. Intravenous concentrations of fasting blood glucose, total cholesterol, HDL-C, low-density lipoprotein cholesterol, and triglyceride were also measured. After extracting DNA from the subjects, mutations of the +188T>C (Trp64Arg) of exon 1 and +3893T>C of intron 2 on the ADRB3 gene were genotyped using the single base extension method. We have identified a novel mutation of ADRB3 that is located in intron 2. The frequency of its minor allele was 0.164. Both the +188T>C mutation of exon 1 and +3893T>C mutation of intron 2 were significantly associated with HDL-C. The mean concentration of serum HDL-C was significantly lower in the presence of their minor allele 'C'. These results suggest that both mutations of +188T>C of exon 1 and +3895T>C of intron 2 have significant associations with HDL-C in the Korean population.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.6 no.3
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• pp.1-18
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• 2011

Publication Industry of scientific technology is showing tendency of decreasing in sales, which clearly draws down curve since 2000. The printing culture is declining whether it is because of trend avoiding pure science or technological science and engineering, advancement of mass media or increasing frequency of using internet. Nevertheless, researcher considered car industry in publication industry as a life-long purpose for study. For this reason, the researcher tried to find the variables of the marketing which give impact on the customers such as student group and consumer who buys cars, when buying professional books. The found variables are expected to have a huge impact on the publication industry of professional books. As a result of research, in the area of the vision and motive, most said that they have "chosen a major in car because they liked car in usual base." In the stage of recognizing the problem, they buy the books when it is inevitably necessary. In the stage of searching for the information, they get information from advertisements, friends, professors, internet or sales clerk in book stores. In the stage of evaluation, they look for the title and the publication date of the books. In addition, in the stage of deciding purchase, "buy immediately" was the most frequent answer while impulsive purchase is the least frequent answer. In the stage of evaluating after purchase, many of them mostly are satisfied with their purchase.

• Journal of Cadastre & Land InformatiX
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• v.52 no.2
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• pp.53-65
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• 2022

According to the advancement of the GNSS satellite positioning system, the module of hardware and operation software reflecting accuracy and economical efficiency is implemented in the user sector including the multi-channel GNSS receiver, the multi-frequency external antenna and the mobile app (App) base public positioning analysis software etc., and the multichannel GNSS RTK positioning of the active configuration method (DIY, Do it yourself) is possible according to the purpose of user. Especially, as the infrastructure of multi-GNSS satellite is expanded and the potential of expansion of utilization according to various modules is highlighted, interest in the utilization of multi-channel low-cost GNSS receiver module is gradually increasing. The purpose of this study is to review the multi-channel low-cost GNSS receivers that are appearing in the mass market in various forms and to analyze the utilization plan of the "address information facility investigation project" of the Ministry of Public Administration and Security by constructing the multi-channel low-cost GNSS positioning module based RTK survey system (hereinafter referred to as "multi-channel GNSS RTK module positioning system"). For this purpose, we constructed a low-cost "multi-channel GNSS RTK module positioning system" by combining related modules such as U-blox's F9P chipset, antenna, Ntrip transmission of GNSS observation data and RTK positioning analysis app through smartphone. Kinematic positioning was performed for circular trajectories, and static positioning was performed for address information facilities. The results of comparative analysis with the Static positioning performance of the geodetic receivers were obtained with 5 fixed points in the experimental site, and the good static surveying performance was obtained with the standard deviation of average ±1.2cm. In addition, the results of the test point for the outline of the circular structure in the orthogonal image composed of the drone image analysis and the Kinematic positioning trajectory of the low cost RTK GNSS receiver showed that the trajectory was very close to the standard deviation of average ±2.5cm. Especially, as a result of applying it to address information facilities, it was possible to verify the utility of spatial information construction at low cost compared to expensive commercial geodetic receivers, so it is expected that various utilization of "multi-channel GNSS RTK module positioning system"