• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.4
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• pp.275-283
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• 2021

In this study, a driver IC for an AC-powered LED that can be manufactured with a low voltage semiconductor process is designed and the performances of the driver IC were simulated. In order to manufacture a driver IC that operates directly at AC 220V, a semiconductor manufacturing process that satisfies a breakdown voltage of 500V or higher is required. A semiconductor manufacturing process for a high-voltage device requires a much higher manufacturing cost than a general semiconductor process for a low-voltage device. Therefore, the LED driver IC is designed in series so that it can be manufactured with semiconductor process technology that implements a low-voltage device. This makes it possible to divide and apply the voltage to each LED block even if the input voltage is high. The LED lighting circuit shows a power factor of 96% at 220V. In the pnp transistor circuit, a very high power factor of 99.7% can be obtained, and it shows a very stable operation regardless of the fluctuation of the input voltage.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.917-921
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• 2004

Principle of mailing list was distributed messages to all subscribers in one time. But mailing list operation has constructed a network traffic problem. Because mailing list manager distributed mails without concentrate on subscriber network. If our network has many of subscribers, there will be redundant data in traffic channel. Submailing list has purpose to reduce problems. Analyses of mailing list characteristic in electronic mail were a feature of submailing list system, which manage by human hand (Network Administrator). That will cause trouble for network traffic if Network Administrator could not seek for mailing list characteristic from e-mails in due time. This article will present ideas and recognize methodology for automatic working in submailing list system. Recognize step begin with capture process, which use to trap e-mail information from transfer channel. Next process is preparing raw data into recognition format. Then the third one is recognize part and find out confidential factor. The last process is make decision and determine which electronic mail has properties of mailing list characteristic. Afterward deliver result to submailing list for carry on.

• IE interfaces
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• v.21 no.1
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• pp.96-108
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• 2008

This paper proposes the systematic design approach for developing the evaluation indicators that evaluate the candidate proposals in the national defense core-technology R&D projects. To improve the validity and fairness of the evaluation indicators, the existing evaluation process in a military and a public sector are surveyed and also the existing evaluation system of the core-technology R&D programs for the national defense is analysed and discussed. A new system for the evaluation indicators is designed by using the axiomatic design, factor analysis and the analytic hierarchy process. It is expected that the proposed evaluation indicators contribute to enhance the fairness and the reliability of the evaluation process for the proposal of the national defense core-technology R&D projects.

• Korean Management Science Review
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• v.27 no.1
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• pp.1-16
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• 2010

According to appearance of a new competitive factor, as 'Green', Green Logistics becomes the important evaluation factor for many firms in emerging competitive environment. Despite this importance, the recognition level of Korean firms on Green Logistics lags behind that of leading companies in developed countries. In addition, the literature studies and practical strategies for systematic management control plans are very insufficient. In this paper, we establish decision making framework of Green Logistics by using ANP(analytic network process). Specifically, we suggest at first the overall concepts and issues of Green Logistics through literature studies. Next, we derive 6 clusters and 21 components forming the strategic green logistics, and then we conduct surveys for pairwise comparison of experts on Green Logistics and compute relative weights of the clusters, components and altanatives considering the feedback structure. We expect that the results of this study will be very helpful for managers to make strategic decisions.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.73-78
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• 2007

The objective of this work was to simulate lead frame etching characteristics to optimize the etching process, Characteristics such as the etching factor and uniformity were investigated for different actual operating conditions, including pressure, distance from the nozzle tip, pipe pitch, and feed speed. The correlation between the etching and spray characteristics was analyzed to develop the etching model. Spray characteristics obtained from an experiment using a phase Doppler anemometer system were then simulated using a Monte-Carlo technique, The etching process model was coded in the Java language, The spray and etching characteristics were correlated with each other and simulated results agreed well with the measured data for a lead frame etching process, The optimal operating parameters under various conditions were successfully determined.

• Journal of Korean Society for Quality Management
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• v.33 no.3
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• pp.91-104
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• 2005

Tolerance analysis plays an important role in design and manufacturing stages for reducing manufacturing cost by improving producibility. In most production processes encountered in practice, a process mean may shift or drift in the long run although process is in control. This study discusses the feasibility of three most common inflation factors(Bender, Gilson and Six Sigma) as a correction to Root Sum of Squares(RSS) method to compensate heuristically for a shift of process mean and nonnormal component distributions from simulation experiments and proposes the guidelines for choosing the inflation factor.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.3
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• pp.47-55
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• 1997

A vacation destination was conceptualized to be chosen through a three-stage process consisting of an early consideration set formation, a late consideration set formation, and a final selection stage. Choice criteria were defined as an individual's belief toward the relationships between perceived attributes, expected outcomes, and the destination. And these criteria were assumed to be divided into benefit-related dimension and perceived risk-related dimension. Through two pilot surveys, 13 items which have 4 factors were identified. used on 4 factor structures, the benefit-related dimension was identified to be consisted of three sub-dimensions, "historic/cultural", "escaped" and "naturalness". A longitudinal panel survey was used to test the differences of the importance of choice dimensions through the choice process. The importance of benefit-related dimension was decreased through the choice process as hypothesized except "naturalness" factor. And as hypothesized, the importance of perceived risk-related dimension was increased.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.199-202
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• 2006

The hardening and anisotropy based on the crystal plasticity is considered in the numerical simulation of hemispherical sheet forming process to find more realistic simulation results For calculating the yield shear stresses of each crystal, Taylor's model of the crystalline aggregate is employed. The yield stress of crystalline aggregate is computed by averaging the yield stresses of the crystal. The hardening is evaluated by using the Taylor factor and the critical resolved shear stress of the crystal. In addition, by observing the crystallographic texture and slip system, the anisotropy of the sheet is traced during the forming process. The anisotropy and hardening behaviors of the sheet found by the crystal plasticity are described better than those of obtained from the Hill's quadratic criterion based on the continuum plasticity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.875-880
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• 2008

In this paper, we deal with the TLP evaluation results for GGNMOS in ESD protection device of conventional CMOS process. An evaluation parameter for GGNMOS is that repeatability evaluation for reference device($W/L=50\;{\mu}m1.0\;{\mu}m$) and following factors for design as gate width, number of finger, present or not for N+ gurad -ring, space of N-field region to contact and present or not for NLDD layer. The result of repeatability was showed uniformity of lower than 1 %. The result for design factor evaluation was ; 1) gate width leading to increase It2, 2) An increase o( finger number was raised current capability(It2), and 3) present of N+ gurad-ring was more effective than not them for current sink. Finally we suggest the optimized design conditions for GGNMOS in evaluated factor as ESD protection device of conventional CMOS process.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.143-147
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• 2000

This describes thermal crack creation process in automotive disks. Thermal cracks have been serious defects which induced disastrous accidents during traveling. The thermal cracks must be regularly eye-inspected. The cracks have been experimentally analysed; but they were not reported by analytic means yet. This paper proposed thermal crack creation process by a computer simulation which enlightened how to investigate thermal crack by cheap means. We explained the disk thermal crack creation and calculated stress intensity factor of an assumed surface crack in an automotive disk.