• 제목/요약/키워드: Cheong-Dae

검색결과 336건 처리시간 0.04초

A Study on the Productivity Analysis and Restructuring of Information Technology Industry Using DEA/WINDOW (DEA/WINDOW 기법을 이용한 정보기술산업의 경영 효율성과 규모 경제성 평가에 관한 연구)

  • Lee, Dae-Yong;Lee, Cheong-Ho
    • Asia pacific journal of information systems
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    • 제10권3호
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    • pp.17-40
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    • 2000
  • This study aims at proposing a direction of improving the efficiency in Korean information technology(IT) industry. In the face of re-engineering which has been done in most industries, it is very important to assess the validity of their restructuring or M&A based on the future efficiency. At first, by using the DEA/WINDOW, we will evaluate how the 30 firms are efficient for outputting their performance with respect to the profit realization and market ability. Then, in order to propose the direction of the efficiency improvement and suitable restructuring strategy, we will clarify how the efficiency of IT firms depends on their firm size. Finally, we will analyze their 'economy of scale' and also reveal how their economy of scale depends on the firm size based on return-to-scale(RTS).

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Verification of biological nitrogen removal model in anoxic-oxic process (무산소-산소 공정에서 생물학적 질소 제거 모델의 검증)

  • Lee Byung-Dae;Cheong Kung-Hoon
    • Journal of Environmental Science International
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    • 제14권12호
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    • pp.1155-1161
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    • 2005
  • Anoxic-oxic process were analyzed numerically for the each unit and final TN effluent by Water Quality Management(WQM) model and the results were compared data from these sewage or wastewater treatment plants. No bugs and logic error were occurred during simulation work. All of the simulation results tried to two times were obtained and both results were almost same thus this model has good reappearance. A few of simulation results were deviated with measured data because lack of influent water qualities are reported however simulation results have wholly good relationship with measured data. Also each unit of simulation result was kept good relationship with that of measured data therefore this WQM model has good reliance. Finally, WQM model predicts final TN effluent within ${\pm}4.1\;mg/{\ell}$

A Comparison study on Grounding design by 1-Dimensional and Soil 2-Dimensional Electrical Resistivity Subvey (1차원 및 2차원 대지비저항 측정에 의한 접지설계 비교)

  • Han, Seong-Gu;Cho, Dae-Hoon;Jung, Chul-Hee;Lyu, Cheong-Hee
    • Proceedings of the KIEE Conference
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    • 대한전기학회 2009년도 제40회 하계학술대회
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    • pp.2188_2190
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    • 2009
  • 대지비저항의 측정 분석에 주로 사용되는 4-점 Wenner 전극법이며 1차원 측정법을 이용한다. 1차원 측정방법은 방법이 간편하며 경제적이지만, 측정방법이 기본적으로 특정한 대지구조를 갖는다고 가정하고 분석하므로 실제의 대지구조와 측정하여 분석한 대지구조 모델이 차이를 갖게 되고, 이로인해 접지설계와 실제시공 결과 사이에 오차가 발생하게 된다. 본 연구에서는 1차원 및 2차원 측정법을 이용하여 분석된 대지구조모델를 이용하여 접지시스템 설계를 수행하였고, 이 결과를 실제현장에 시공하여 각각의 특성을 비교 분석하였다.

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A Study on Mechanical Parts for Smooth Lift by 6 Sigma (6시그마를 이용한 유연승강부품에 관한 연구)

  • Cheong, Seon-Hwan;Choi, Seong-Dae;Cho, Gyu-Yeol
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • 제5권2호
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    • pp.36-41
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    • 2006
  • This study was carried out to install the lifting force of a two hinge type stand mechanism by 6 Sigma process in advance. This unit is designed for the display device in order to enhance the ergonomics for effective height adjustment and maintenance at any preferred position. The unit will be very useful for the mechanism fabricated with coil springs and disc springs as a torque generator. The 6 Sigma process was applied to select two key factors among 7 elements to lift the head unit and to find out applicable tolerance securing the 3.4 ppm of defects as well as what deviation of lifting force we can expect between calculation and experiment at the design stage of development. The result of this study can be applied to various units for the optimization of the smooth lift.

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Effects of Mold Precision in Micromini Cellphone Optical Systems (초소형 휴대폰 광학계의 금형 정밀도가 광학성능에 미치는 영향)

  • Ye, In-Soo;Cheong, Seon-Hwan;Choi, Seong-Dae;Hyun, Dong-Hoon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • 제19권5호
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    • pp.660-666
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    • 2010
  • In cellphone optical systems, a tiny difference of manufacturing has a strong influence on camera lenses. This study aims to find out the worst result by tolerances come from all parts in optical performance. First, 3D Measure Instrument, Roundness Measure Instrument, and Wavelength Measure Instrument were used for greater precision by making and measuring the parts to see how different from the drawings. It was confirmed that even narrow tolerances could result in defects by assembling. Tolerances in assembly should be concerned as those in parts through the research.

Towards Understanding the Value of a Loyal Customer in Electronic Commerce: An Expectation-Disconfirmation Theory (전자상거래에서 충성고객 가치에 대한 이해: 기대 불일치 이론을 중심으로)

  • Coo, Chulmo;Koh, Chang E.;Lee, Dae Yong;Lee, Cheong-Ho
    • Knowledge Management Research
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    • 제9권2호
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    • pp.129-146
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    • 2008
  • Customers' evaluation of Website with satisfaction is critical in electroniccommerce. Previous research has studied in a distinct approach; especially IT oriented constructs-perceived usefulness, easy of use and marketing oriented constructs-product, shopping experience, service quality. Despite those important previous studies regarding the usage and the purchase of goods and services, how consumers are satisfied and why consumers leave Web sites without purchasing have not been extensively researched. This study explored those determinants of consumer satisfaction with Web site using expectation-disconfirmation theory (EDT). The present paper extends the range of EDT from antecedents of expectation to consequence of satisfaction. The result suggests that experience and familiarity has an impact on expectation as well as perceived performance and satisfaction. Second, higher expectation makes a negative impact on disconfirmation of expectation. Third, positive disconfirmation of expectation makes a positive impact on satisfaction. Forth. satisfaction produces loyalty and repurchasing intention. Finally, loyal customer has stronger intention to repurchase than satisfied customer.

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Electroluminescence and Electronic properties of multi1ayer organic Thin Film (다층구조를 갖는 유기박막의 발광 및 전자물성)

  • Lee, Cheong-Hak;Kim, Jeong-Tae;Park, Bok-Kee;Park, Dae-Hee
    • Proceedings of the KIEE Conference
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    • 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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    • pp.792-794
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    • 1998
  • The TPD and the $Alq_3$ film are widely used as a hole transport layer and an emitter layer respectively, in organic electroluminescent(EL) device (ITO Glass/TPD/$Alq_3$/metal). In this structure, we fabricated two models. Model(1) having ITO glass/$Alq_3$/Al structure and model(2) having ITO Glass/TPD/$Alq_3$/Al structure were fabricated by the vacuum evaporation. The comparison between model(1) and model(2) was made about the absorbance, the wave length, the current-voltage characteristic and the ln I - $V^{(1/2)}$characteristic respectively. Electroluminescence of green and wavelength of 510[nm] were observed in both model. We observed absorbance from 320[nm] to 430[nm] in $Alq_3$ material and from 250[nm] to 400[nm] in TPD material.

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Synthesis and Photophysical Properties of Nano-sized Y$_{2}$O$_{3}$:Eu$^{3+}$ and Y$_{2}$O$_{3}$:Eu$^{3+}$-Gd$^{3+}$ phosphors (Eu$^{3+}$과 Eu$^{3+}$-Gd$^{3+}$이 첨가된 Y$_{2}$O$_{3}$ 나노 형광체의 제작 및 광물리적 특성 연구)

  • Hong, Gyeong-Su;Yu, Dae-Hwang;Park, Jong-Ho;Kim, Cheong-Sik;Yang, Ho-Sun;Mun, Byeong-Gi;Seo, Hyo-Jin;Gwak, Min-Gi
    • Proceedings of the Optical Society of Korea Conference
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    • 한국광학회 2005년도 제16회 정기총회 및 동계학술발표회
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    • pp.102-103
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    • 2005
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Value Engineering Approach for Heat Curing Method Under Cold Weather Condition (한중콘크리트 보온양생 공법에 대한 VE분석)

  • Woo, Dae-Hun;Kim, Tae-Cheong;Kim, Jong;Jeon, Chung-Keun;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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    • pp.21-23
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    • 2010
  • This study was conducted to draw various decisive elements of a reasonable heat curing method and to examine the importance in deciding a construction method when constructing cold weather concrete. As a result, the items proposed as important elements at the time of decision of a heat curing method included economy, workability, maintainability, insulation capability, reduced construction period and usability. As a result of importance by items under AHP technique, it was found the most important element was insulation capability, followed by reduced construction period and workability. As a result of comparison of a heat supplying and a heat insulation method by dual bubble sheet differed 2 times as much as a heat supplying method, especially the evaluation degree by insulation capability and reduced construction period was high.

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