• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.77-87
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• 1994

One of the often espoused merits of close-range photogrammetry is the effectiveness of the method for measuring non-accessible objects of unusual and complex shape. In this study, techniques of deformation measurement using close-range photogrammetry for electric power structures were developed. Absolute deformation could be found efficiently through close-range photogrammetry in the structure deformation analysis based on time variation. Also, feasibility of the structures management system was presented based on this study.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.371-375
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• 2006

A computational work has been performed to investigate the aerodynamics of a projectile which is launched from a ballistic range. A moving coordinate method for a multi-domain technique is employed to simulate unsteady projectile flows with a moving boundary. The variation of a virtual mass and the shape of projectile are added to the axisymmetric unsteady Euler equation systems. The present computational results properly predict the velocity, acceleration, drag histories and the major flow characteristics of the projectile.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.9
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• pp.411-416
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• 2001

Distance relay is the most widely used in transmission line protection because it is applicable not only as main protection but also as back-up protection. However, the protection range of the distance relay is always fixed in the unchangeable operating range while the power system varies, and therefore the distance relay is the device that is the highly influenced by the power system changes. In this regard, this paper describes an approach to minimize the mal-operation of the distance relay due to the power system changes through changing protection range of the distance relay into optimal condition in response to the load variation and power system condition. Also mal-function of the distance repay in case of high resistance ground faults could be minimized through modeling the protection range into quadratic function.

• Journal of Life Science
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• v.12 no.1
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• pp.9-13
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• 2002

Crepidiastrum lanceolatum ($H_{OUTT}$) $N_{AKAI}$ (Compositae) is distributed in East Asia including Korea. Genetic diversity and population structure of six C. lanceolatum populations in Korea and two populations in Japan were determined using genetic variation at 19 allozyme loci. The percent of polymorphic loci within the enzymes was 42.1%. Genetic diversity at the species level and at the population level was low (Hes : 0.077; Hep : 0.068, respectively), where-as the extent of the population divergence was relatively low ($G_{ST}$ : 0.093). One of the most striking features of this study was the more significant difference within populations than among populations. An indirect estimate of the number of migrants per generation (Nm : 2.44) indicated that gene flow was moderate among eight populations of the species. In addition, analysis of fixation indices revealed a slight heterozygosity deficiency in some populations and at some loci. Narrow geographic ranges, short-lived perennial herbaceous, and small population sizes are mainly associated with the low level of genetic variation.n.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.434-436
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• 1996

This paper investigates the optimal design of an electronic ballast of half bridge inverter type in consideration of the variation of ambient temperatures for a 15[W] triple-type compact fluorescent lamp. The performances of electronic ballasts under different values or the capacitance ratio in the resonant tank circuit are compared with each other in the practical temperature range between 15[$^{\circ}C$] and 35[$^{\circ}C$] to determine its optimum value. As a result, the optimum value is found to be such that $C_1/C_2=10$ at which value starting of the lamp is most stable and light output reaches its maximum value with lowest variation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1174-1179
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• 2009

In this paper we develop the characteristic of density on non-uniform plasma in different layer of the semiconductor with optically controlled microwave pulses. The transient response of the microwave pulses in different plasma layer has been evaluated by calculating the variation of the reflection function of dielectric microstrip lines. The lines has used under open-ended termination containing optically induced plasma region, which has illuminated a laser source. The characteristics impedances resulting from the presence of plasma are evaluated by the transmission line model. The analyzes the variation of transient response in a 0.01cm layer near the surface for frequency range from 1GHz to 128GHz. The diffusion length LD is larger than compared to the absorption depth $l/_{\alpha}l$. The variation of characteristic response in plasma layer with microwave pulses which has in deferentially localized has been evaluated analytically.

• 한국해양학회지
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• v.19 no.1
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• pp.31-35
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• 1984

The seasonal variation of sea surface temperatures (SST) in the neighbouring seas of Korea was studied performing the harmonic analysis of the monthly mean SST data of 15 years (1961-1975) at 182 stations routinely collected by the Fisheries Research and Development Agency. The mean SST in the West Sea (Yellow Sea) is lower than that in the East Sea (Sea of Japan) whereas the annual range of SST in the West Sea is much larger than that in the East Sea. The maximum SST occurs between mid August and early September. The seasonal variation of SST in the seas of Korea is influenced by incoming radiation and heat advections by ocean currents and winds.

• Journal of The Korean Astronomical Society
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• v.27 no.2
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• pp.133-146
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• 1994

We have detected a SiO maser line (v=1, J=2- 1) for 15 stars out of about 80 long period variables in the wide range of period. No new sources are detected; all detected sources are variables with period longer than 300 days; no evidence is found that the dust grains in the outer envelope have influenced on this line. The time variation of this maser line for 7 stars, T Cep, ${\mu} Cep$, U Her, R Leo, R Lmi, U Ori, and R Ser is observed and compared with optical light curve at the same epoch of maser observation. No universial relation between the time variation and the optical light curve is found. It implies that the radiation from a central star does not much play an important role for the direct pumping of the SiO maser line.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.5
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• pp.709-717
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• 2000

Cyclic variability has long been recognized as limiting the range of operating conditions of spark ignition engines, in particular, under lean and highly diluted operation conditions. The cyclic combustion variations can be characterized by the pressure parameters, combustion parameters, and flame front parameters. The coefficient of variation in indicated mean effective pressure ($COV_{IMEP}$) defines the cyclic variability in indicated work per cycle, and it has been found that vehicle driveability problems usually result when $COV_{IMEP}$ exceeds about 10%. For analysis of the cyclic variability in SI engines at idling, the results show that cyclic variability by the $COV_{IMEP}$ or the coefficient of variation in maximum pressure can be explained and may be consequently reduced by the help of the optimum spark timings.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.251-257
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• 2015

This work presents modelling and simulation of a readout integrated circuit (ROIC) design considering pair-wise serial configuration along with thermal modeling of an uncooled microbolometer array. A fully differential approach is used at the input stage in order to reduce fixed pattern noise due to the process variation and self-heating-related issues. Each pair of microbolometers is pulse-biased such that they both fall under the same self-heating point along the self-heating trend line. A ${\pm}10%$ process variation is considered. The proposed design is simulated with a reference input image consisting of an array of $127{\times}92$ pixels. This configuration uses only one unity gain differential amplifier along with a single 14-bit analog-to-digital converter in order to minimize the dynamic range requirement of the ROIC.