• Journal of the Korean Society for Heat Treatment
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• v.7 no.1
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• pp.25-34
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• 1994

To investigate the effect of austenitizing tempratures on the mechanical properties and corrosion resistance of 0.19%C-13.6%Cr martensitic stainless steel, the changes in martensitic trasformation temperatures, mechanical properties and anodic polarization curve were examined after changing the austenitizing temperatures and tempering temperatures. On increasing heating rate at the same austenitizing temperatures, $A_s$, $A_r$ and $M_s$ increased. And the $M_s$ temperature showed to be decreased with increasing austenitizing temperature. With increasing tempering temperature up to $500^{\circ}C$, strength, hardness and impact value were not changed remarkably, on the other hand the tensile strength and hardness decreased and impact value increased after tempering above $550^{\circ}C$ owing to the $M_{23}C_6$ carbide precipitation. The abrupt decrease in elongation at the tempering temperture of $500^{\circ}C$ proved to the precipitation of $M_7C_3$ carbide. The effect of austenitizing temperature on the mechanical properties of the tempered specimen showed to be decreased in impact value and elongation at the austenitizing temperature of $1150^{\circ}C$. At low tempering temperatures the corrosion resistance of the tempered specimen was not changed obviously with increasing tempering temperature. On the other hand, the resistance decreased above the tempering temperature of $600^{\circ}C$ due to the precipitation of $M_{23}C_6$ carbides. The corrosion resistance showed to be improved with increasing the austenitizing temperature owing to the dissolution of carbides.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.638-642
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• 2002

User in video data utilization of high-capacity can grasp whole video data at a look. Offer frame list that summarize information of video data to do so that can remake video from branch that want when need. Need index process of video data for effective video retrieval. This treatise wishes to propose effective method about scene change point detection of video that is been based on contents base index. Proposed method video data so that can grasp whole structure of video detection color value of schedule pixel for diagonal line direction in image sampling do. Data that get into sampling could grasp scene change point on one eye. Color value of pixel that detection in each frame is i frame number by i$\times$j procession to procession A, j stores to reflex height of frame. Introduce MSE and calculate mean error of each frame. If exceed mean error and schedule critical value, wish to detect the frame for scene change point.

• Archives of design research
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• no.16
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• pp.17-25
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• 1996

, \l!ernatives in multi dimensional decision prohlems generally possess numerous attrihutes by which they can be describ('d and compared, The ('\';dllation factors include all attributes that have Ic\'(']s specified by quantitative and qualitativc objectil'l'S, Howev'('f since qualitative factors arc difficul! to quantify as num('ral estimates, these factors have tended to bl' ignored without regard for their importance to human contrnl. In this study, the author adapted :j ('va]uation methods with critrria which have qualitative and qualitative attributes: the Intuitive Evaluation ~1cthods the Accumulativc' Evaluation Model the Benchmarking Evaluation Methods, and studied the corrC'iation between them, The results show that Ill(' :j Mrthods have reciprocal relationships under reliability (r=O, (XX)]] In order to removl' obstacles of desi!;n ev'aluation ( lots of timl' l'llnsumption, constr;lints of placc" difficulties of hu!;!' data procc'ssin!;), it is necessary to be developed a new ('va]uation syst('rn which could prov'idc' effective rat in!; of desi!;n v'alm's 10 make value judw'rnents, , \l!ernatives in multi dimensional decision prohlems generally possess numerous attrihutes by which they can be describ('d and compared, The ('\';dllation factors include all attributes that have Ic\'(']s specified by quantitative and qualitativc objectil'l'S, Howev'('f since qualitative factors arc difficul! to quantify as num('ral estimates, these factors have tended to bl' ignored without regard for their importance to human contrnl. In this study, the author adapted :j ('va]uation methods with critrria which have qualitative and qualitative attributes: the Intuitive Evaluation ~1cthods the Accumulativc' Evaluation Model the Benchmarking Evaluation Methods, and studied the corrC'iation between them, The results show that Ill(' :j Mrthods have reciprocal relationships under reliability (r=O, (XX)]] In order to removl' obstacles of desi!;n ev'aluation ( lots of timl' l'llnsumption, constr;lints of placc" difficulties of hu!;!' data procc'ssin!;), it is necessary to be developed a new ('va]uation syst('rn which could prov'idc' effective rat in!; of desi!;n v'alm's 10 make value judw'rnents,alm's 10 make value judw'rnents,

• Electrical & Electronic Materials
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• v.10 no.6
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• pp.519-527
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• 1997

The micro crack was occurred where the stress concentrated by the thermal stress which was induced during the cooling period after molding process or by the various reliability tests. In order to estimate the possibility of development from inside micro crack to outside fracture, the fracture toughness of EMC should be measured under the various applicable condition. But study was conducted very rarely for the above area. In order to provide a was to decide the fracture resistance of EMC (Epoxy Molding Compound) of plastic package which is produced by using transfer molding method, measuring fracture is studied. The specimens were made with various EMC material. The diverse combination of test conditions, such as different temperature, temperature /humidity conditions, different filler shapes, and post cure treatment, were tried to examine the effects of environmental condition on the fracture toughness. This study proposed a way which could improve the reliability of LOC(Lead On Chip) type package by comparing the measured $J_{IC}$ of EMC and the calculated J-integral value from FEM(Finite Element Method). The measured $K_{IC}$ value of EMC above glass transition temperature dropped sharply as the temperature increased. The $K_{IC}$ was observed to be higher before the post cure treatment than after the post cure treatment. The change of $J_{IC}$ was significant by time change. J-integral was calculated to have maximum value the angle of the direction of fracture at the lead tip was 0 degree in SOJ package and -30 degree in TSOP package. The results FEM simulation were well agreed with the results of measurement within 5% tolerance. The package crack was proved to be affected more by the structure than by the composing material of package. The structure and the composing material are the variables to reduce the package crack.ack.

• Kyungpook Mathematical Journal
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• v.23 no.2
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• pp.115-128
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• 1983

• Kyungpook Mathematical Journal
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• v.21 no.2
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• pp.167-170
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• 1981

• Wind and Structures
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• v.3 no.1
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• pp.69-71
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• 2000

• Journal of the Korean Society for information Management
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• v.24 no.1 s.63
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• pp.187-208
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• 2007

This study aims to present a new approach to measure the economic value of the public libraries, identifying and suggesting the modified contingent valuation method (CVM) application. The modified CVM, which applied Dissonance Minimizing (DM) format, is presented as a new approach. A cost-benefit analysis is used as a tool to determine if the benefits of public libraries outweigh the cost incurred in providing the services. The benefits of public libraries are based on estimates of how much the user is willing to pay for the library services and costs are based on the prices of providing the services. A comparison between two methods are conducted in a case study in order to measure the economic value of 'J Public Library'. The study also conducts a case study to analyse the WTP value of the 'J Public Library' and demonstrates how public libraries approach the their local studies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.79-84
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• 2008

We are developing a small-sized high temperature superconducting magnetic energy storage (HTS-SMES) magnet with the nominal storage capacity of 600 kJ, which provides electric power with high quality to sensitive electric loads. Critical current and N-value of a high temperature superconductor with large current, which was selected for the development of the 600 kJ HTS-SMES magnet, were investigated in various oblique external magnetic fields. Based on the critical current and N-value measured for the short sample conductor, we discussed the DC V - I characteristic of a model coil fabricated with the same conductor of 500 m. The results show that the measured critical current and N-value of the conductor for parallel field are constant in external magnetic fields less than about 0.2 T. However, for oblique fields, its critical current and N -value abruptly decrease in all external magnetic fields. Moreover, the measured critical current of the model coil well agrees with the numerically calculated one based on the DC V - I characteristic measured for the short sample conductor. This suggest that losses and critical currents for an HTS-SMES magnet made up of a high temperature superconductor with anisotropic characteristic are predictable from the data of a short sample conductor.

• Bulletin of the Korean Mathematical Society
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• v.35 no.3
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• pp.473-484
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• 1998

We consider a finite difference approximation to a singular boundary value problem arising in the study of a nonlinear circular membrane under normal pressure. It is proved that the rate of convergence is $O(h^2)$. To obtain the solution of the finite difference equation, an iterative scheme converging monotonically to the solution of the finite difference equation is introduced. And the numerical experiment of this method is given.