• Proceedings of the KSRS Conference
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• v.2
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• pp.764-767
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• 2006

It can be important framework data to monitor the change of land-use pattern of river boundary in design and management of river. This study analyzed the change of land-use pattern of Gab- and Yudeung River using time-series aerial images. To do this, we carried out radiation and geometric correction of image, and estimated land-use changes in inland and floodplain. As the analysis of inland, the ratio of residential, commercial, industrial, educational and public area, that is urbanized element, increases, but that of agricultural area shows a decline on the basis of 1990. Also, Minimum Distance Method, which is a kind of supervised classification method, is applied to extract water-body and sand bar layer in floodplain. As the analysis of land-use, the ratio of level-upped riverside land and water-body increases, but that of sand bar decreases. These time-series land use information can be important decision making data to evaluate the urbanization of river boundary, and especially it gives us goodness in river development project such as the composition of ecological habitat.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.64-70
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• 2008

This paper briefly discusses the main sources of errors and their solutions for measuring hydrogen uptake from gas phase by the Sieverts technique. Correction of volumetric errors of apparatus, density of hydrogen storage material, estimation of temperature gradient are investigated. Systematic errors and the change of density of the host material according to the pressure have been the subject of much controversy in recent years. We considered the standard ball calibration, temperature gradient distribution, pretreatment of hydrogen storage materials to minimize errors. We could lessen the miscalculations after applying those methods to Equilibrium pressure-composition isotherm data.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.50-54
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• 1997

An expert drawbead model is developed to model a cranky drawbead in the finite element analysis of stamping processes. The expert model calculates the drawbead restraining forces (DBRF's) and bead-exit thinning, which are boundary conditions. DBRF's are calculated by considering bending force, unbending force, and friction force in order. Bead-exit thinning are due to the bending and tension during the deformation. The DBFR's and thinning computed form the mathematical model for the basic beads are compared with measurements and correction factors compensating for the differences are found using the multiple linear regression method. The composition beads are assumed to be a combination of basic beads so that the DBRF's and bead-exit thinning are computed to the sum of those of basic beads.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.185-190
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• 2003

The most shortcoming of metalhalide lamps is what the instant restarting cannot be realized when the arc tube is in the hot condition. The discharge starting voltage of arc tube in the hot condition is much higher than in the cold condition. Therefore it takes about five minutes to restart the metalhalide lamps, that is to say, it is possible to start when the pressure and the temperature are decreased. But, if the lamp is restarted in the hot condition, we must supply the high voltage pulse with 20kV at the both sides of lamp. The proposed electronic ballast is consist of a electromagnetic interference (EMI) filter, a power factor correction (PFC) circuit, a flyback converter, a half-bridge inverter, and a high voltage igniter circuit. By this composition we can restart the lamp with the voltage 20kV, even if the lamp is in the hot condition.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.6
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• pp.1-9
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• 2022

This study introduces the calculation model of ionization composition and electrical conductivity for metallic plasma for practical application to modeling and simulation of modern electrical detonators. The present model includes the correction for non-ideality of dense plasma conditions which are expected in electrical explosion of bridge in detonators. The computational results for copper plasma show favorable agreement with experimental data for a wide range of plasma temperature and high density conditions and the model is proper for detonator modeling with good prediction accuracy.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.1
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• pp.25-34
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• 2024

The Satellite Based Augmentation System (SBAS) improves the accuracy and reliability of user positioning by transmitting the error correction and integrity information of the global navigation satellite system signal from geostationary satellites in real time. For this reason, SBAS was designed for aircraft operations and approach procedures and is now in operational or development stages in many countries. Time has passed since the construction of SBAS and many changes have occurred in the composition of the monitoring stations and the geostationary satellites. These changes have been investigated and the current operation and development status of SBAS globally are surveyed. The development and test schedules for the transition to dual frequency multi-constellation, an important topic in SBAS, are discussed.

• Journal of Biosystems Engineering
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• v.7 no.1
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• pp.1-16
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• 1982

The thermal conductivies of grain are influenced by many physical factors such as' initial temperature, moisture content, composition, bulk density or porosity of grain. However, not only few researchers considered all these factors in determining thermal conductivities of grain but also many researchers considered only moisture content as a major effective factor on the thermal conductivity. This study was conducted to experimentally determine the thermal conductivities of rough rice (3 Japonica-type, 3 Indica-type) and barley(covered, naked) as a function of initial temperature, moisture content and porosity of grain, and to investigate the effect of those physical factors on the thermal conductivities of grain. The results of this study are summarized as follows; 1. The average time correction value for this experimental apparatus was 7 sec, which. was insignificant to the calculated thermal conductivity. The resulting conductivity for considering time correction value was only 4.9 percent higher than that calculated by the non-corrected equation. 2. The thermal conductivity was in the range of 0.1208~0.2058W/$m^{\circ}K$ for naked barley, 0.1138~0.1724W/$m^{\circ}K$ for covered barley, 0.0912~0.1864W/$m^{\circ}K$ for Japonica-type rice and 0.086~0.1774W/$m^{\circ}K$ for Indica-type rice. 3. The thermal conductivities of grain increased with initial temperature and moisture content of grain but decreased with porosity of grain. 4. The regression equations of the thermal conductivity of each grain were determined as a function of initial temperature, moisture content and porosity. The regression equations of the thermal conductivity of both Japonica-type and Indica-type rough rice were also determined.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.1-8
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• 1994

The flame speed correlation considering thermal-hydraulic phenomena under severe accidents is proposed and correction coefficients are defined. This correlation modifies the pressure dependency in Iijima-Takeno correlation and adds the steam suppression effects to it in the anticipated hydrogen and steam concentration ranges under severe accidents. The existing models of flame speed due to hydrogen combustion under severe accidents are based on the experiments which were performed merely at room temperature and atmospheric pressure. They have difficulty in predicting a accurate flame speed in a case of high temperature and pressure during severe accidents. Thus the flame structure is assumed as a prerequisite to the reliable determination of flame speed and theoretical model is developed. To examine the validity, flame speeds in various conditions calculated by this model are compared with those obtained by the calculation of the existing correlations of the codes such as improved HECTR and MAAP. Also the steam suppression ratio is quantified and the steam suppression coefficient is defined as a composition of mixture. Initial temperature and pressure dependencies are investigated and correction coefficents are determined. More experimental studies can be recommended to improve this correlation to its further works.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.371-383
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• 2004

In this paper we consider technological requirements to broadcast digital television signals using single frequency networks (SFN) in the Advanced Television Systems Committee (ATSC) transmission systems and propose equalization digital on-channel repeater (EDOCR) that overcomes the limitations of conventional digital on-channel repeaters (DOCRs). Since there are no forward error correction (FEC) decoder and encoder, the EDOCR does not have an ambiguity problem. In addition, since an adaptive equalizer in the EDOCR removes multi-path signals, additive white Gaussian noise (A WGN), and feedback signal due to low antenna isolation, the EDOCR may have good output signal quality with high power.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.3
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• pp.149-157
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• 2019

Purpose : This study aims to check the relationship between the size of curvature in scoliosis patients and the reduction rate of curvature after wearing a brace and the relationships of the size of curvature and correction angle with Body Mass Index (BMI). Methods : With 30 adolescent girls who had never worn a brace, their Cobb angle and BMI were measured before manufacturing braces, and their corrected Cobb angle was measured after wearing the manufactured scoliosis braces. Results : The size of the major curvature before wearing the brace and the reduction rate of the curvature after putting it on had a negative correlation in both the major curvature (r=-.465, p<.01) and the minor curvature (r=-.516, p<.01). The size of the minor curvature and the reduction rate of the minor curvature before and after putting it on also had a negative correlation (r=-.429, p<.05). As for the relationship between the size of curvature and BMI, they had a negative correlation in both the major curvature (r=-.141) and the minor curvature (r=-.123), and as for the relationship between the reduction rate of curvature and BMI after wearing the brace, they had a positive correlation in both the major curvature (r=.251) and the minor curvature (r=.136); however, it was not statistically significant (p>.05). Conclusion : In conclusion, the larger the size of curvature, the lower the reduction rate of curvature after wearing the brace became. The larger the size of curvature, the lower the BMI became. The higher the BMI, the higher the correction ratio of the brace became. Therefore, it is judged that it is necessary to provide early treatment and manage body composition before scoliosis progresses.