• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.954-960
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• 2008

The effects of elastic modulus coefficient and linear expansion coefficient of overhead distribution power line(ACSR $58 mm^2$) on sag behavior in distribution line have been investigated to clarify the difference between specification and experimental level. The elastic modulus coefficients of Al wire and steel wire were $5,182.6 kgf/mm^2,\;18,348.8 kgf/mm^2$, respectively Therefore, the computational composition elastic modulus coefficient of the power line was $7,063.5 kgf/mm^2$, while that of experimentally measured was $7681.1 kgf/mm^2$. As a result, we found that elastic modulus coefficient which was experimentally measured was higher than that of computational by 8.7 %. However, when planner designs the sag of disoibution line, the elastic modulus coefficient of power line $8,400 kgf/mm^2$ should be generally adopted. These two different using values lead to the sag difference of 0.62 m. The other results will be discussed.

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.19-26
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• 2010

An influence factors for soundness evaluation of river levee include consisting embankment in case piping, permeability coefficient of ground, height of embankment, the width of crest, material characteristics of embankment and foundation ground, shape of embankment slope, an influence for penetration of rainfall or river water in case slope stability. In this study, it was operated a feasibility investigation of existing design result, stability evaluation for permeability coefficient use and permeability coefficient change of foundation ground to investigate an influence in line with permeability coefficient change for result of river levee penetration analysis. The evaluation results of influence factors, the permeability coefficient was used in design and it was evaluated influence in safety factor of piping. After the evaluation of influence factors, the permeability coefficient used in the design appears with the fact that differs in a design report about same soil.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.2
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• pp.53-59
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• 1986

On the slamming analysis of ship design the data for the impact pressure acted on the forward bottom of a ship are needed. Furthermore impact pressure is given by the function of both the hull form coefficient and relative velocity. In this papper. a simplified method to estimate hull form coefficient by perso;,al computer (p. c.) is studied. This numerical analysis was applied to the model of the Mariner type. and then the result by the p. c. was compared with that by IBM 7090 computer. Main results obtained are as follows: 1. The result by the developed p. c. method had fairly good agreement with that by conventional large computer (IBM 7090) within 2% error. 2. This developed method' by p. c. may be applied to the initial estimation of the K-value because of the close agreement between the ship lines by the results of p. c. and that of input.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.7-12
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• 2012

The cutting force for peripheral end-milling considering run-out property was estimated and its result was compared with that of measured one. An experimental coefficient modelling was used for the formulation of theoretical end-milling force by considering the specific cutting force coefficient. Also, the specific cutting force, that is the multiplication of specific cutting force coefficient and uncut chip thickness, was used for the prediction of end-milling force. The end-milling force mechanics with run-out was presented for the estimation of theoretical force in peripheral end-milling by considering the geometric shape of the workpiece part. As a result, the estimated end-milling force shows a good consistency with the measured one. And it can be used for the prediction of force history in end-milling with run-out which incurs different start and exit immersion angle in entering and exiting condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.483-483
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• 2012

Recently, nonthermal bioplasma has been attracted by researchers due to their potentials to modulate cellular functions resulting in changes of biomolecular electron band structures as well as cell morphologies. We have investigated the secondary electron emission characteristics from the surface of the erythrocyte, i.e., red blood cell (RBC) with and without the nonthermal bioplasma treatment in morphological and biomolecular aspects. The morphologies have been controlled by osmotic pressure and biomolecular structures were changed by well known reactive oxygen species. Ion-induced secondary electron emission coefficient have been measured by using gamma-focused ion beam (${\gamma}$-FIB) system, based on the quantum mechanical Auger neutralization theory. Our result suggests that the nonthermal bioplasma treatment on biological cells could result in change of the secondary electron emission coefficient characterizing the biomolecular valence band electron energy structures caused by the cell morphologies as well as its surface charge distributions.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.5
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• pp.3-15
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• 2006

The purpose of the study is to determine grid cell of radar relationship, and to promote the radar data on hydrology field. The study region is the Chungjudam basin with a drainage area of $6,648km^{2}$ located within the 260 km circle under the DWSR-88C C-band umbrella(Kwanak Mt Radar). Grid cell was produced to extract radar reflectivity and rainfall data of the same time and point using Arc-view software package. The grid cell size is to estimate mean correlation coefficient for $1km{\times}1km,\;2km{\times}2km,\;3km{\times}3km$ grid. The result of mean correlation coefficient showed good result(0.57) for the $1km{\times}1km$ grid cell. The 32 rainfall stations Z-R relationship was estimated in Chungjudam basin.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.483-488
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• 2004

The inter-laboratory comparison test which is demanded on the authorized test of ISO/IEC 17025 is the program to guarantee the confidence of test result. This paper, as a part of the inter-laboratory comparison test between South Korea and China, is refered to the characteristic of friction coefficient of disk brake lining for rolling stock according to disk type. Brake tests were carried out under constant brake force and operating sequence by using dynamo-tester according to disk and disk lining types. To establishing the confidence of test result, we calculated A type uncertainty about friction coefficient and investigated the factors about the variation of friction coefficient.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2004-2007
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• 2002

In the linear combination type stereophonic echo canceller, it is known not to converge the coefficient vector of the adaptive filter to a correct echo path. In this report, we analyze the convergence value of the filter coefficient vector of the stereo echo canceling algorithm using input signals of all channels in relation to this problem. In this analysis, one of the two inputs to the un-known system and adaptive one are assumed to be a delayed and attenuated version of the other signal as a model of the input signal with a strong cross-correlation. As a result, it is shown for the coefficient vectors not to converge to echo paths, and nor to converge to the value which depends on the time delay and the attenuation of the input signal. We show that the computer simulation result are corresponding to our analytical results.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.8
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• pp.147-159
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• 1994

The performance of the improvement method of spatial resolution for satellite images based on the generalized inverse matrix is superior to the conventional methods. But, this method calculates the coefficient values for extracting the spatial information from the relation between a small pixel and large pixels. Accordingly it has the problem of remaining the blocky patterns at the result image. In this paper, a new generalized inverse matrix method is proposed which is different in the calculation method of coefficient values for extracting the spatial information. In this proposed metod, it calculates the coefficient values for extracting the spatial information from the relation between a small pixel and small pixels. Consequently it can improve the spatial resolution more efficiently without remaining the blocky patterns at the result image. The effectiveness of the proposed method is varified by simulation experiments with real TM image data.

• ETRI Journal
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• v.43 no.5
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• pp.923-931
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• 2021

We studied the influence of GaAs top-layer thickness on the small-signal modulation response and 56 Gb/s four-level pulse-amplitude modulation eye quality of 850 nm vertical-cavity surface-emitting lasers (VCSELs). We considered the proportionality of the gain-saturation coefficient to the photon lifetime. The simulation results that employed the transfer-matrix method and laser rate equations led to the conclusion that the proportionality should be considered for proper explanation of the experimental results. From the obtained optical eyes, we could determine an optimum thickness of the GaAs top layer that rendered the best eye quality of VCSEL. We also compared two results: one result with a fixed gain-saturation coefficient and the other that considered the proportionality. The former result with the constant gain-saturation coefficient demonstrated a better eye quality and a wider optimum range of the GaAs top-layer thickness because the resultant higher damping reduced the relaxation oscillation.