• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.117-122
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• 1987

Glass forming ranges in the AlF3-(Mg＋Sr＋Ba)F2-P2O5 system are studied and ultraviolet transmission, infrared transmission, coefficient of refractive index, thermal expansion coefficient, density and chemical durability of the glasses are determined. Glass forming range is restricted MgF2 0-10wt%, SrF2 10-50wt%, BaF2 10-40wt% in this system. While BaF2 is substituted by SrF2, density and refractive index are decreased, micro hardness and thermal expansion coefficient are increased according to the increasing of SrF2 at fixed MgF2 contents. These samples represent high transmittance(93%) from 400nm to 3800nm and chemical durability of these samples show less than 0.3mg/$\textrm{cm}^2$$.$hy by weightloss.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.726-732
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• 2011

To establish the transmission system expansion plan based on reliability, valuation of outage cost become more important. In previous studies about outage cost estimation, macroscopic, microscopic and analytic methods are proposed but they have some limit. For instance, microscopic method involves a complex field survey process and macroscopic method can not estimate regional outage cost. So in this paper, a new method to estimate regional macroscopic outage cost using the reduction of value added due to power outages is proposed. This method uses regional add value according to production activities called Gross Regional Domestic Product(GRDP) and regional electricity sales.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.702-708
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• 2016

The torque converter is deformed according to the rotating speed and control pressure when engine power is transferred to the transmission. This deformation, which is called ballooning phenomenon, occurs mainly at the outer side by the centrifugal force of the automatic transmission fluid (ATF) and the control pressure from the valve body. Although the torque converter is slightly deformed when rotating, the ballooning phenomenon affects fluid performance, efficiency and durability. Thus, expansion characteristics analysis is important in determining torus size, control pressure and structure. In this paper, an analysis equation and FEM model was developed to investigate the expansion characteristics. Using this model, structural analysis was performed to investigate the relationships between deformation and the torus diameter. The results were confirmed by comparing with the test results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.11
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• pp.4443-4462
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• 2020

This paper proposes a new framework of reversible data hiding scheme for absolute moment truncation coding (AMBTC) compressed images. AMBTC-based RDH can be applied to optical remote sensing (ORS) image transmission, which achieves target region preservation and image compression simultaneously. Existing methods can be concluded as two types. In type I schemes, stego codes mimic the original AMBTC format where no file bloat occurs, yet the carried secret data is limited. Type II schemes utilize predication errors to recode quantity levels of AMBTC codes which achieves significant increase in embedding capacity. However, such recoding causes bloat inside stego format, which is not appropriate in mentioned ORS transmission. The proposed method is a novel type I RDH method which prevents bloat inside AMBTC stego codes with significant improvement in embedding capacity. The AMBTC compressed trios are grouped into two categories according to a given threshold. In smooth trio, the modified low quantity level is constructed by concatenating Huffman codes and secret bits. The reversible contrast mapping (RCM) is performed to complex trios for data embedment. Experiments show that the proposed scheme provides highest payload compared with existing type I methods. Meanwhile, no expansion inside stego codes is caused.

• Proceedings of the Acoustical Society of Korea Conference
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• 1984.12a
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• pp.11-14
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• 1984

• Proceedings of the KIEE Conference
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• 1984.07a
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• pp.151-153
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• 1984

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.481-490
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• 2007

WASP which is used to plan generation expansion has disadvantages that can't manage environmental factors and regional supply-demand planning. But with the effectuation of the United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol, it is expected that reducing greenhouse gases affects power system in its long-term generation expansion planning. Therefore national countermeasures is needed. This paper formulates a mathematical model considering CO2 emission constraints and Emission Trading that will be enforced. This model is based on the MEFISET (Model for Economic Feasibility of Interstate Electrical Ties) which was made by Korea Energy Economics Institute and Hong-ik university and manages generation expansion planning. And this mathematical model is verified by studying a case system.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.557-559
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• 2005

This paper proposes a method for choosing the best composite power system expansion plan considering a contingency security criterion. The proposed method minimizes the investment budget fer constructing new transmission lines subject to contingency criterion. it models the power system expansion problem as an integer programming one. The method solves for the optimal strategy using a branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Although the proposed method is applied to a simple sample study, the test results demonstrate that the proposed method is suitable for solving the power system expansion-planning problem subject to practical future uncertainties.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.164-166
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• 2006

Wien Automatic System Planning Package (WASP) which is used to draw out generation expansion planning applies Dynamic Programming in Korea power system panning. While this package has an advantage that computes annual capacity, it has a disadvantage that can't consider environmental constraints. With the effectuation of the Kyoto Protocol in February, 2005, it is expected that CO2 emission has a severe effect on Korean power system. Therefore, as the most important issue, the generation expansion planning considering environmental constraints is rising in power system. This paper develops a mathematic model including not only generation expansion planning but transmission planning and considering regional supply-demand and environmental constraints, especially CO2 emission, and verifies propriety through the case study.

• East Asian Economic Review
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• v.18 no.2
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• pp.143-161
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• 2014

This paper examines the effects of global liquidity expansion on advanced and emerging economies by using panel VAR methodology. The results show that global liquidity expansion tends to boost economy by increasing GDP growth and stock prices. However, we find that the effects are asymmetric. The effects of global liquidity on GDP and stock prices are greater and more persistent in emerging economies than in liquidity recipient advanced economies. Moreover, global liquidity appreciates emerging economies' exchange rates more persistently than those of advanced economies. Lastly, while global liquidity expansion increases foreign portfolio investment inflows to Asian countries and liquidity recipient advanced economies, there is no evidence for Latin American countries.