• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.1 s.104
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• pp.45-51
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• 2006

In this paper, a new predistortion linearizer for controlling the amplitude of low frequency intermodulation distortion signals is proposed. The low frequency intermodulation distortion(IMD) components are generated by harmonic generator. A vector modulator, modulate fundamental signal with low frequency IMD signals, generates predistortion IMD signals and controls amplitude and phase of them with modulation factors. As a result, this predistorter is suppressed IMD signals of power amplifier effectively. The predistortion linearizer has been manufactured to operate in cellular base-station transmitting band($869{\sim}894\;MHz$). The experimental results show that IMD3 of power amplifier are improved more than 20 dB for CW two-tone signals. Also, it's improved the adjacent channel power ratio(ACPR) more than 10 dB for IS-95 CDMA IFA signals.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1239-1245
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• 2005

In this paper, a new predistortion linearizer using second harmonic components feedforwarding is proposed. The harmonic generator of the proposed predistorter that consists of a small signal amplifier extracts second harmonic signals. A vector modulator that modulate fundamental signal with second harmonic signals, generates the inverse third order intermodulation distortion signals and controls amplitude/phase of them with modulation factors. As a result, this linearizer is suppressed IMD3 signals of power amplifier effectively. The test results show that the third order IMD of power amplifier is suppressed more than 20 dB for CW two-tone signals. Also, it's improved the adjacent channel power ratio(ACPR) more than 5 dB for CDMA(IS-95) 4FA signals.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.4 no.2
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• pp.73-88
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• 2009

This research is to observe the misbehavior of child, and identify relevance maternal propensity for perfection - one of parents factors that affect the misbehavior of child - to the misbehavior of child. The objects of this study 274 children of 3-5 years who were attending nursery schools and kindergartens in Gyeonggi province and Busan City as well as their mothers of the same number. The result of the research provides the fundamental data about the mother and child relationship with the parent's factor which gives an effect to child's misbehavior and reveals mother's psychological nature of the functional parts of a perfectionism and the disfunction as part of this.

• Fashion & Textile Research Journal
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• v.20 no.4
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• pp.389-399
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• 2018

The purpose of this study was to investigate the differences of sociocultural attitudes toward appearance, clothing and cosmetics purchasing behaviors according to male consumer's age group. The research method was survey and subjects were 656 male consumers. The results were as follows. First, three factors (appearance importance awareness, appearance internalization, and slimness importance awareness) were emerged on sociocultural attitudes toward appearance. Young age group showed higher level of appearance importance awareness and internalization than middle age group. Second, there were many differences on clothing purchasing behaviors by age variable. Young age group more importantly considered psycho-social purchasing motives, aesthetic selection criteria, and the internet as information source and purchasing place than middle age group. Whereas middle age group more importantly considered practical purchasing motives, practical selection criteria, and store display & salesman as information sources, and fashion outlet as purchasing place than young age group. Third, there were also many differences on cosmetics purchasing behaviors by age variable. Young age group used more and various cosmetics, and they more importantly considered skin improvement as purchasing motive, skin suitability and price as selection criteria, the internet as information source and purchasing place than middle age group. On the other hand, middle age group generally used fundamental cosmetics, and they more importantly considered skin protection as purchasing motive, quality as selection criterion, TV and store display & salesman as information sources, and discount store and cosmetics speciality store as purchasing places than young age group.

• Information Systems Review
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• v.8 no.3
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• pp.225-243
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• 2006

Recently mother company-driven informatization projects have been widely launched for the suppliers. Setting up a proprietary evaluation system for the level of informatization of the suppliers, a mother company provides both financial and consulting supports for the suppliers in order to enhance the utilization level of the ERP(Enterprise Resource Planning) system. With the utilization level enhanced, the whole collaboration network will create a competitive advantage to win over global competition. This paper investigates critical success factors for ERP operational performances through a Samsung Electronics case study. The result of the case study may provide valuable feedback to the strategic decision making and fundamental insights for these collaboration efforts.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.751-756
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• 2010

Ultrasonic nonlinearity is very sensitive to changes in material properties. This paper describes the study of the correlation between heat treatment and ultrasonic nonlinearity by taking nonlinear factors into consideration. A modified formula was proposed for ultrasonic velocity. This formula indicated that the changes occurring in nonlinearity during heat treatments cause changes in the ultrasonic velocity. The experimental results show that the relative nonlinearity parameters calculated from the modified ultrasonic velocities and the ratio of amplitudes of the second harmonic and fundamental wave are in good agreement. The experimental results prove that heat treatment can result in changes in material nonlinearity. Moreover, the relative nonlinearity parameter calculated from the modified velocity formula is has a large value. Since this parameter has high sensitivity to changes in nonlinearity, it can be used to represent the relative nonlinearity change calculated in this study by using the modified formula for ultrasonic velocity.

• Journal of the Korean Society of Costume
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• v.57 no.3 s.112
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• pp.14-22
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• 2007

This study is about the excavated costume representing fundamental "Conservation and Restoration". It's not a report of a specific case, but it is a guideline that contains the costume and textile of museum collection. It is not research based on experiments; however, this paper is basically consists of various reported-documents. Followings are the conclusions of this study 1. These are the factors that we have to know to prevent the causes of fabric's degradation. -Light, -Humidity and temperature, -Microscopic organism, -Insect and rodent animal, -Air pollution, -Ph, -Handling 2. Basic principles of conservation and restoration follows are: -Select the Reversible method, -Represent the easily distinguishable repaired place, -Should be acted by an expert or people with experience, -Before the restoration, accurate and specified records should be completed, -Procedure, treatment method, and materials used should be recorded prior to restoration, -Should be cared minimally, -Be cautious when using the conservation materials, -When caring, make sure nothing is against the principle of aesthetic, historic, and form of preservation 3. The types of restoration are type of straight or curve, type of hole, type of without warp or weft, type of special part damage something like sleeve, collar, type of form that is severely damaged, and type of separated pieces. 4. The method of restoration is sewing, stitching, and the combination of sewing and stitching. 5. The restoration seams are welt seam, plain seam, flat felled seam, french seam etc. And there are kinds of used-sewing, such as, broad stitching, backstitch, half backstitch, basking, hemming, saddle stitching etc.

• Fire Science and Engineering
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• v.22 no.2
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• pp.9-19
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• 2008

Recently the systematic change in the fire and disaster prevention administration, which was less studied than other administrative systems, has been in progress. In particular, the fire service demands are increasing and forms are diversified. The first thing you must do is to make up the fire service power according to the fire service demands. Such an allocation results in social welfare satisfaction. The purpose of this study is to investigate the determinants of fire service force. And this study investigates that fire service demand is affected by socioeconomic factor. To do this, this study reviews fire service force, the fire service demand, socioeconomic factor and financial factor. And this study sets up four hypotheses based on the theoretical backgrounds and the past research. The statistical method used for the verification of hypotheses are multiple regression analysis and structural equitation analysis. The analysis showed that fire service demand and financial factor were positive significant variable for fire service power. But socioeconomic factor was a negative significant variable. Also the analysis showed that social factor was a positive significant variable and economic factor was a negative significant variable for fire service demand.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.701-708
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• 2018

Human error is an important cause of maritime accidents and the identification of human error is fundamental to maritime-accident preventions. In particular, the pattern of technical behavior taken in the circumstance of bridge teams(navigator & helmsman) provides important information to identify human error. The purpose of this study is to identify and analyze technical behavior pattern of bridge teams using Williamson's turn for rescue of persons overboard. The focus of this study is to build and analyze a cognitive model of the human behavior factors of the bridge teams in the process of implementing the experiments. The experimental environment was constructed using a ship-handling simulator and conducted an experiment on participants from 24 bridge teams. As a result of the experiment, it was able to identify the behavior pattern of the ship's maneuvering and maintain trajectory using the rudder and engine. This study is expected to correct human error in the bridge teams application to the certification and training of seafarers.

• Steel and Composite Structures
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• v.36 no.3
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• pp.355-367
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• 2020

The current work, present dynamic analysis of the FG-sandwich plate seated on elastic foundation with various kinds of support using refined shear deformation theory. The present analytical model is simplified which the unknowns number are reduced. The zero-shear stresses at the free surfaces of the FG-sandwich plate are ensured without introducing any correction factors. The four equations of motion are determined via Hamilton's principle and solved by Galerkin's approach for FG-sandwich plate with three kinds of the support. The proposed analytical model is verified by comparing the results with those obtained by other theories existing in the literature. The parametric studies are presented to detect the various parameters influencing the fundamental frequencies of the symmetric and non-symmetric FG-sandwich plate with various boundary conditions.