• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.4
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• pp.425-432
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• 2004

The objective of this study is a qualitative comparison between line-integrated OH chemiluminescence(OH$\^$*/) image and its Abel inverted image to investigate the flame structure at different phase of the oscillating pressure field. PIV(Particle Image Velocimetry) measurements were conducted under non-reacting conditions to see the global flow structure and NOx emission was measured to investigate the effect of fuel-air premixing on combustion instability and emission characteristics. Experiments were carried out in an atmospheric pressure, laboratory-scale dump combustor operating on natural gas. Combustion instabilities in present study exhibited a longitudinal mode with a dominant frequency of ∼341.8㎐, which corresponded to a quarter wave mode of combustor. Heat release and pressure waves were in-phase when instability occurred. Results gave an insight about the location where the strong coherence of pressure and heat release existed. Also an additional information on active control to suppress the combustion instabilities was obtained. For lean premixed combustion, strong correlation between OH$\^$*/ and NOx emissions was expected largely due to the exponential dependence of thermal NOx mechanism on flame temperature.

• Journal of Engineering Education Research
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• v.18 no.4
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• pp.45-56
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• 2015

The goal of this study was to analyze the research trends of engineering education in elementary and secondary education. To accomplish this goal, this study analyzed the journal papers by 'published year', 'research topic', 'research subject', 'research method' and 'related school subject'. Followings are the results of this study. First, regarding the published year, the studies related to the elementary and secondary school level engineering education had been conducted 1 to 3 pieces intermittently from 1995 to 2009. And the number of studies are more than 5 pieces after 2010. Second, regarding the research topic, the number of study followed by 'investigation for current status', 'tendency analysis', 'development of teaching method or model', 'verification of teaching method/models' effect'. Third, regarding the research subject, the number of study followed by 'student', 'literature', 'professor', 'teacher'. Fourth, regarding the research method, the number of study followed by 'survey research' and 'literature research', 'qualitative research', 'experimental research' and 'integrated research'. Fifth, regarding the related subject, the number of study followed by 'science', 'technology', 'mathematics', 'practical arts'. Based on the results of this study, there are the needs for further studies to establish theoretical foundation on the engineering content elements in elementary and secondary school level, analyze on related variables and effects, develop engineering assessment instrument, use a variety of research methods, and conduct study on the applications of engineering in math subject.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.209-215
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• 2002

A study of the guideway vehicle was made for a comparison of ride stabilities between its two primary steering types; one is the front wheel steering and the other the front-rear wheel. A numerical model as a closed loop system was built for an investigation of various factors to have an influence on the vehicular critical speed which is closely associated with ridabilities. It was shown that dynamics stabilities of the front steering type was much better over a large value of steering gain and the longer distance between front axle and guide link for both types provided better stabilities as well. A large steering gain ratio of the front to the rear significantly plays an important role in an improvement of stability in the front-rear steering. To observe a qualitative trend on stability behaviors, the root locus was obtained by considering a time lag which may be frequently caused by the complicated steering mechanism. In performing so, the appropriate selection of steering gain had a greater effect on the front-rear steering vehicle far more ride comfort. In addition, the dynamics model proposed here can be utilized for a more accurate evaluation on the vehicle design in lateral or yawing absorber and moreover expanded for the analysis of independent four-wheel steering vehicle.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.190-197
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• 1999

Electronic speckle contouring(ESC) is the optical method for measuring shape by using fringe-projection techniques in electronic speckle pattern interferometry. It has the advantage of being non-contacting and can also give a field view of the surface under investigation. Fringes in ESC represent the difference in depth along the view direction between the master wavefront and the test component. The contour maps of three-dimensional diffuse objects are obtained by small shifts of optical fiber carrying the dual-object-beams and 4-frame phase shift. We proposed the contouring method by shifting the collimated illumination beams through optical fiber in order to obtain the contour fringe patterns. And also, we performed addition of incremental addition of images and experiments based on it. we obtained both quantitative increment without decorrelation effect and qualitative improvement by reducing the noise of contour fringes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.36-39
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• 2000

A small electrical potential difference which appears on any solid body when subjected to illumination by a modulated light beam generated by laser is called photocharge voltage(PCV)[1,2]. This voltage is proportional to the induced change in the surface electrical charge and is capacitatively measured on various materials such as conductors, semiconductors, ceramics, dielectrics and biological objects. The amplitude of the detected signal depends on the type of material under investigation, and on the surface properties of the sample. In photocharge voltage spectroscopy measurements[3], the sample is illuminated by both a steady state monochromatic bias light and the pulsed laser. The monochromatic light is used to created a variation in the steady state population of trap levels in the surface and space charge region of semiconductor samples which does result in a change in the measured voltage. Using this technique the spatial variation of PCV can be utilized to evalulate the surface conditions of the sample and the variation of the PCV due to the monochromatic bias light are utilized to charactrize the surface states. A qualitative analysis of the proposed measuremen is present along with experimental results performed on amorphous silicon samples. The deposition temperature was varied in order to obtain samples with different structural, optical and electronic properties and measurements are related to the defect density in amorphous thin film.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.149-158
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• 2010

This study is a comparative analysis of the creation and development of visual techniques used in girls' comics in the paradigmatic low and high-context cultures of American and Japan. As previous analyses have shown, there are qualitative differences in the expressive mechanisms employed in girls' comics in Eastern and Western cultures, and it is an investigation of this realm of expression that is the basis of this study. Particular emphasis is placed on an analysis of the structure of frames, one of the most fundamental expressive mechanisms in girls' comics. A close examination of this underlying structural component reveals that both cultures demonstrate autonomous growth, providing a theoretical framework for future studies.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.4
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• pp.495-505
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• 2014

This study investigated the type of fashion brand concepts and derived the components of fashion brand concepts. A total of 125 brand concept texts of women's wear brands were collected from "2012/2013 Korea Fashion Brand Annual" (S. M. Kim, 2012). A qualitative research method was employed. To investigate the types of fashion brand concepts, the texts were classified into three types such as functional, symbolic, and experiential concepts, and four complex types such as functional/symbolic, functional/experiential, symbolic/experiential, and functional/symbolic/experiential concepts. Open coding and axial coding provided the components of fashion brand concepts. The results were as follows. First, an investigation of the types of fashion brand concepts indicated differences in the types of fashion brand concepts and the types of general product brand concepts. One content of a fashion brand concept could be interpreted as more than two concept types; consequently, many fashion brand concepts did not fit the notion of the types of general product brand concept. Most fashion brand concepts simultaneously encompassed more than two types of brand concepts at once. Second, the components of fashion brand concepts consisted of 55 subjects, 7 sub-categories (physical/intrinsic product characteristics, symbolic/conceptual product characteristics, target demographics, target consumer behavior, brand capability, brand values, and brand management/marketing) and 3 categories (product, target consumer, and brand).

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.69
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• pp.633-654
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• 2016

Recently open data has been spread rapidly in the world include Korea. Accordingly in international trade field open data and using it became a key point to get competitiveness. In this study, the author make an attempt to suggest the way for quality improvement of international trade information by looking for some problems with crating and using the information. Thus, the problems of using information are can be point out as follows. Firstly the range of open data is narrow. Secondly the management of the open data is not conducted properly. Thirdly the suppliers of the open data didn't prepare some investigation system for their data's usability for user. Expansion of the organizations who open data is one way to solve quantitative problem. There are four suggestions to solve qualitative problems. Firstly the guidelines should be established and operated in each organizations respectively. Secondly the criterion of expenses for open data should be arranged among the concerned parties. Thirdly the ability of the manpower and organization who charged in the quality improvement of information should be reinforced both quantitatively and qualitatively. Lastly the system for data usability for user should be equipped in early stages. Finally the author emphasize the establishment of total management system for using open data in international trade is not needed only the efforts of the specific parties but also all parties led by Ministry of Industry, Trade and Energy in order to carry out above suggestions successfully.

• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.695-705
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• 2015

Distressed structures require necessary remedial measures in order to restore their original structural properties like strength and stiffness. Validating the effectiveness of the proposed qualitative remedial measure experimentally is of utmost importance as there is no well-established analytical method to verify the effectiveness of the same quantitatively. Prototype testing which would have been the best option for this purpose would not only prove costly but also be associated with numerous practical difficulties; hence model testing is resorted as the only option for the purpose. This paper presents one such typical experimental study on the structural behavior of a distressed bridge, mainly observed in the form of prominent tilt in the bearing plate in transverse and longitudinal direction on downstream side. The main focus of the proposed experimental investigation is to assess the structural behavior particularly the load carrying capacity. The extent of deformation of some models with specific structural arrangements and some models with specific need based remedial measures were also studied. This study also assessed the contribution of each remedial measure towards restoration individually and collectively.

• Journal of Distribution Science
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• v.17 no.2
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• pp.13-23
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• 2019

Purpose - Corporate activities for enhancing and improving corporate performance can largely be divided into exploration and exploitation. The purpose of this study is to examine the impact of implementing organizational ambidexterity in SMEs, including distribution firms, by reviewing the extant literature and deriving the basis on which this strategy affects the managerial performance. Research, design, and methodology - The study uses a systematic review methodology, which employs a structured process to discern trends and meaningful themes across a wide body of literature on specific subjects and research questions. This qualitative study examined the influence of ambidextrous strategies of SMEs on firm performance, and the results were synthesized from the literature. Results - Organizational ambidexterity in SMEs is related to the firm's managerial performance. However, it is crucial to know that there are many ways to generate an ambidextrous organization, and decisions about what method to choose should be based on the environmental aspects of the enterprise. Conclusions - The following aspects should be considered for execution; : making practical decisions based on accurate information about the resources the firm has, considering the organizational level of human resources for implementing organizational ambidexterity, and sharing specific performance goals.