• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.57.5-58
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• 2015

We describe relations between modern cosmology and general relativity in the historical context. We reveal some ironies imbedded in Einstein's final correction of his gravitational field equation in the context of cosmology in 1917 which has apparently opened a new era of modern physical cosmology. The ugly (according to Einstein) correction term was introduced only to build a static cosmology which turns out to be in flat contradiction with observation. Somehow, however, it is the correction term which has saved the modern cosmology from the genuine creativity of nature continuously revealed by astronomical observations. Whether the present precision cosmology is also a correct one is often ignored by the practitioners but still a pressing open question left for future theoretical and observational pursuits.

• Special Issue of the Society of Naval Architects of Korea
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• 2006.09a
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• pp.59-64
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• 2006

Most important factor to consider funnel performance is exhaust gas temperature and exhaust gas concentration Electric equipments on the wheelhouse top affected exhaust gas temperature. So, it is important that electric equipments keep away from high temperature. Though exhaust gas concentration is not a regulation and restraint, the exhaust 9as can cause serious problems for the on-board air quality and result in irreversible damage to the ship and people. So, we pocus on the exhaust gas concentration also. When judge whether a measured concentration is acceptable or not, criteria based on the LTEL (Long Term Exposure Limit). In this paper, we carried out the smoke simulation study. For this analysis, we used FLUENT which is commercial CFD (Computational Fluid Dynamics) code.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.29-32
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• 1993

A technique computing short-term load foadcasting is essential for monitoring and controlling power system operation. This paper shows the use of general exponential smoothing to develop an adaptive forecasting system based on observed value of hourly demand. Forecasts of hourly load with lead times of one to twenty-four hours are computed at hourly intervals throughout the week. Standard error for lead times of one to twenty-four hour range from three to four percent average load. Studies are planned to investigate the use of weather influence to increase forecast accuracy.

• Journal of The Korea Institute of Healthcare Architecture
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• v.16 no.2
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• pp.65-75
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• 2010

Space transformation of hospital architecture happens more rapidly than other types such as school and office buildings. This requirement is caused by medical demand, service transformation, technical development and equipment changes. Grand scale extension and rapid change in hospital architecture affects whole planning; therefore, it is important to design in the macro perspective such like Life Cycle. Grand scale extension is difficult process to rebuild growth and transfer of hospital architecture and to adapt to the future change. That's why simple planning gives limits to some departments in a short-term and brings another reform such as more extension or interior renovation in a long-term. This study surveys various space transformation and grand scale extension of EB hospital extended recently, and it is to find planning condition in extension.

• Journal of the Korean Mathematical Society
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• v.58 no.4
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• pp.1001-1017
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• 2021

In this paper, we first apply parabolic inequalities and a maximum principle to give a new proof for symmetry and monotonicity of solutions to fractional elliptic equations with gradient term by the method of moving planes. Under the condition of suitable initial value, by maximum principles for the fractional parabolic equations, we obtain symmetry and monotonicity of positive solutions for each finite time to nonlinear fractional parabolic equations in a bounded domain and the whole space. More generally, if bounded domain is a ball, then we show that the solution is radially symmetric and monotone decreasing about the origin for each finite time. We firmly believe that parabolic inequalities and a maximum principle introduced here can be conveniently applied to study a variety of nonlocal elliptic and parabolic problems with more general operators and more general nonlinearities.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.320-323
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• 2004

In general, polymer concrete has more excellent mechanical properties and durability than Portland cement concrete, but very sensitive to heat and has large deformations. In this study, the long-term creep behaviors was predicted by the short-term creep test, and then the characteristic of creep of recycled-PET polymer concrete was defined by material and experimental variables. The error in the predicted long-term creep values is less than 5 percent for all polymer concrete systems. The filler carry out an important role to restrict the creep strains of recycled PET polymer concrete. The creep strain and specific on using the CaCO3 were less than using fly-ash. the creep increases with an increase in the applied stress, but not proportional the rate of stress increase ratio. The creep behavior of polymer concrete using recycled polyester resin is not a linear viscoelastic behavior.

• Proceedings of the KIEE Conference
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• summer
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• pp.683-685
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• 2004

This paper introduces a basic design for the short-term load forecasting system using a commercial data base. The proposed system uses a hybrid load forecasting method using fuzzy linear regression for forecasting of weekends and Monday and general exponential smoothing for forecasting of weekdays. The temperature sensitive is used to improve the accuracy of the load forecasting during the summer season. MS-SQL Sever has been used a commercial data base for the proposed system and the database is operated by ADO(ActiveX Data Objects) and RDO(Remote Data Object). Database has been constructed by altering the historical load data for the past 38 years. The weather iDormation is included in the database. The developed short-term load forecasting system is developed as a user friendly system based on GUI(Graphical User interface) using MFC(Microsoft Foundation Class). Test results show that the developed system efficiently performs short-term load forecasting.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.380-385
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• 2001

In this paper, in order to get rid of danger trapped Local minimum point, disadvantage of General Back-propagation and simultaneously obtain fast teaming-speed. We propose PID Back-Propagation with Momentum Term(PID-BPMT) and Design PID Controller by Neural Network with Momentum term. Consider to apply for that Controller in position control system by driven D.C servo motor. its useful performance is verified by computer simulation

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1601-1606
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• 2004

In this paper, the unsteady behavior of the viscous flow field past an impulsively started elliptic cylinder is studied numerically. In order to analyze flow field, we introduce vortex particle method. The vorticity transport equation is solved by fractional step algorithm which splits into convection term and diffusion term. The convection term is calculated with Biot-Savart law, the no-through boundary condition is employed on solid boundaries. The diffusion term is modified based on the scheme of particle strength exchange. The particle redistributed scheme for general geometry is adapted. The flows around an elliptic cylinder are investigated for various attack angles at Reynolds number 200. The comparison between numerical results of present study and experimental data shows good agreements.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.809-817
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• 2004

In this paper, the unsteady behavior of the viscous flow field past an impulsively started elliptic cylinder is studied numerically. In order to analyze flow field, we introduce vortex particle method. The vorticity transport equation is solved by fractional step algorithm which splits into convection term and diffusion term. The convection term is calculated with Biot-Savart law, the no-through boundary condition is employed on solid boundaries. The diffusion term is modified based on the scheme of particle strength exchange. The particle redistributed scheme for general geometry is adapted. The flows around an elliptic cylinder are investigated for various attack angles at Reynolds number 200. The comparison between numerical results of present study and experimental data shows good agreements.