• Fire Science and Engineering
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• 제24권5호
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• pp.136-141
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• 2010

The purpose of this study is to examine the structure and heat generation mechanism of low voltage switches used to turn on or off the power supply to an indoor lighting system and investigate how the fixtures and movable contacts of the switches are damaged depending on the types of energy sources in order to secure the judgment base for expected PL disputes. Based on the Korean Standard (KS) testing method for incombustibility, this study applied a general flame to the switch. In addition, current was supplied to the switch using the PCITS (Primary Current Injection Test System). The ambient temperature and humidity were maintained at $22{\pm}2^{\circ}C$ and 40~60% respectively while performing the test. It is thought that the switch generated heat due to a defective connection of the wire and clip, insulation deterioration and defective contact of the movable contact, etc. The surface of the switch damaged by the general flame was uniformly carbonized. When the flame source was removed, the fire on the switch was extinguished naturally. From the result obtained by disassembling the switch carbonized by the general flame, it could be seen that fixtures and movable contacts remained in comparatively good shape but the enclosure, clip support, movable contact, indicating lamp, etc. showed carbonization and discoloration. In the case of the switch damaged by overcurrent, the clip connecting the wires, clip support, etc. showed almost no trace of damage, but the fixtures, movable contact, indicating lamp, etc. were severely carbonized. That is, the sections with high contact resistance were intensively damaged and showed a damage pattern indicating that carbonization progressed from the inside to the outside. Therefore, it is possible to judge the initial energy source by analyzing the characteristics of the carbonization pattern and the metal fixtures of damaged switches.

• Geophysics and Geophysical Exploration
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• 제4권4호
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• pp.133-144
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• 2001

An effective seismic reflection technique for mapping the cavities and bedrock surface in carbonate rocks is described. The high resolution seismic reflection images were successfully registered by using the hydrophones employed in the stream-water driven trench, and were effectively focused by applying optimal data processing sequences. The strategy included enhancement of the signal interfered with the large-amplitude scattering noise, through pre- and post stack processing such as time-variant filtering, bad-trace editing, residual statics, velocity analysis, and careful muting after NMO (normal moveout) correction. The major reflections including the bedrock surface were mapped with the desired resolution and were correlated to the seismic crosshole tomographic data. Shallow major reflectors could be identified and analyzed on the AGC (auto gain control)-applied field records. Three subhorizontal layers were identified with their distinct velocities; overburden (<3000 m/s), sediments (3000-4000 m/s), limestone bedrock (>4000 m/s). Taking into account of no diffraction effects in the field records, gravel-rich overburdens and sediments are considered to be well sorted. Based on the images mapped consistently on the whole survey line and seismic velocity increasing with depth, this area probably lacks in sizable cavities (if any, no air-filled cavities).

• Korean journal of communication and information
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• 제48권
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• pp.211-230
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• 2009

This study aims to trace the main tendency found in Korean broadcasting news coverage of terror throughout the kidnapping of Sun Il Kim. For this purpose, this study analyzed the contents of 386 news stories found in KBS, MBC, and SBS. Through this process, it investigated the main theme and source found in the coverage of kidnapping. In addition, it analyzed how the press described Al Tawhid Al Jihad, known as the organization who kidnapped Mr. Kim and how well the press transmit the social, historical background of terror. As a result, the dominant theme found in three news company was that which dealt with investigations about suspicions about kidnapping and suspicions related to the kidnapping. However, the voice against dispatching armed forces and the demand of terrorist were seldom found in the coverage. The news sources which three broadcasting news depended on heavily was governmental officials and the media including Al Jazeera was also main source. The description of Al Tawhid Al Jihad by the press was somewhat negative and the expression 'militarized forces' were found mostly. The news which announced the social, historical background of terror were minimal, which indicated that the coverage of terror in Korean broadcasting was still episodic.

• Journal of the Mineralogical Society of Korea
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• 제21권1호
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• pp.67-83
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• 2008

The sericite ore deposits formed in the Precambrian granitic rock at the Bonghwa area, Kyungsangbuk-do, South Korea. The geochemical and mineralogical characteristics of sericite occurred in Daehyun and Seonghwang mine were analyzed using petrographic microscope, XRD, EPMA, XRF and ICP. An alteration mechanism was also studied. Sericitization occurred within the granitic rock by hydrothermal alteration. From the careful study on the occurrence and mineral assemblage, four alteration zone were clearly identified. These zones reflect progressive hydrothermal alteration process. All sericites belong to $2M_1$ polytype and their mineralogical and geochemical properties are close to illite. The sericite ores show various colors, but the characteristics of major element compositions and crystal structures are not different. The trace element analysis, however, indicates that the difference in color attribute to the abundance of Cr and Ti: bluish green colored sericite are enriched in Cr and blackish green colored sericite enriched in Ti. The formation of sericite ore deposit in the granitic rocks are closely relate to fracture system such as fault and joint. It is considered that the sericite ore deposits in this area were formed by very simple hydrothermal alteration occurred along the fracture zones in granitic rocks with absence of other hydrothermally altered minerals such as kaolin and pyrophyllite.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제19권9호
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• pp.1719-1729
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• 1994

In this paper, an adaptive CAC(Connection Admission Control) method is proposed. The adaptive CAC uses traffic estimates derived from both traffic parameter specified by user and cell flow measurements. Traffic estimation using user-specified parameters is performed at every moment of connection request or connection release by recursive formula which makes real-time calculation possible. Traffic estimation using cell flow measurement is carried out when the number of connected calls does not change during a measurement reflection period-renewal period. The most import ant thing for the traffic estimation using cell flow measurement is the determination of the length of a renewal period to trace a real traffic flow with an allowable time lag and the measurement reflection ratio(MRR) both to reduce the portion of overestimation and to avoid underestimation of real traffic flow. To solve these problems, the adaptive CAC updates renewal period and MRR adaptively according to the number of connections and the elapsed time after last connection or release respectively. Performance analysis for the proposed method is evaluated in several aspects for the cases of both homogeneous and heterogeneous bursty traffic. Numerical examples show the adaptive CAC method has the better performance compared with conventional CAC method based on burst model from the both utilization and QOS point of view.

• Journal of the Institute of Convergence Signal Processing
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• 제11권1호
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• pp.47-52
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• 2010

For cryptographic systems, nonlinearity is crucial since most linear systems are easily decipherable. C.Bracken, Z.Zhaetc., propose the APN(Almost Perfect Nonlinear) functions with the properties similar to those of the bent functions with perfect nonlinearity. We design two kinds of new code sequence generating algorithms using the above APN functions. And we find that the out of phase ${\tau}\;{\neq}\;0$, autocorrelation functions, $R_{ii}(\tau)$ and the crosscorrelation functions, $R_{ik}(\tau)$ of the binary code sequences generated by two new algorithms over GF(2), have three values of {-1, $-1-2^{n/2}$, $-1+2^{n/2}$}. We also find that the out of phase ${\tau}\;{\neq}\;0$, autocorrelation functions, $R_{p,ii}(\tau)$ and the crosscorrelation functions, $R_{p,ik}(\tau)$ of the nonbinary code sequences generated by the modified algorithms over GF(p), $p\;{\geq}\;3$, have also three values of {$-1+p^{n-1}$, $-1-p^{(n-1)/2}+p^{n-1}$, $-1+p^{(n-1)/2}p^{n-1}$}. We show that these code sequences have the characteristics of the correlation functions similar to those of Gold code sequences.

• Analytical Science and Technology
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• 제30권6호
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• pp.355-378
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• 2017

Because neurochemicals are related to homeostasis and cognitive and behavioral functions in human body and because they enable the diagnosis of numerous neurodegenerative disorders, there has been increasing interest in the development of analytical platforms for neurochemical profiling in biological samples. In particular, mass spectrometry (MS)-based analytical methods combined with chromatographic separation have been widely used to profile neurochemicals in metabolic pathways. However, development of delicate sample preparation procedures and highly sensitive instrumental detection is necessary considering the trace levels and chemical instabilities of neurochemicals in biological samples. Therefore, in this review, analytical trends in MS-based metabolomics approaches to neurochemicals in multiple biological samples, such as urine, blood, CSF, and biological tissues, are discussed. This paper is expected to contribute to the development of an analytical platform to discover biomarkers that will aid diagnosis, prognosis, and treatment of neurodegenerative disorders.

• Journal of the Korean Vacuum Society
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• 제6권1호
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• pp.9-19
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• 1997

The reaction mechanisms of dry cleaning with UV-excited chlorine radical for Zn, Fe and Ti trace contaminants on the Si wafer have been studied by SEM, AFM and XPS analyses in this work. The patterned Zn, Fe and Ti films were deposited on the Si wafer surface by thermal evaporation and changes in the surface morphology after dry cleaning with $Cl_2$and UV/$Cl_2$at $200^{\circ}C$ were studied by optical microscopy and SEM. In addition, changes in the surface roughness of Si wafer with the cleaning was observed by AFM. The chemical bonding states of the Zn, Fe and Ti deposited silicon surface were observed with in-line XPS analysis. Zn and Fe were easily cleaned in the form of volatile zinc-chloride and iron-chloride as verified by the surface morphology changes. Ti which forms involatile oxides was not easily removed at room temperature but was slightly removed by UV/$Cl_2$at elevated temperature of $200^{\circ}C$. It was also found that the surface roughness of the Si wafer increased after $Cl_2$and UV/$Cl_2$cleaning. Therefore, the metallic contaminants on the Si wafer can be easily removed at lower temperature without surface damage by a continuous process using wet cleaning followed by UV/$Cl_2$dry cleaning.

• Journal of Life Science
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• 제23권8호
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• pp.1004-1009
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• 2013

The biochemical compositions and nutritive values of six species of seaweeds were analyzed to determine their applicability in functional foods or ingredients. The biochemical compositions (moisture, ash, protein, lipid, and dietary fiber) and fatty acid contents were determined for the following seaweed extracts: Phaeophyceae (Laminaria japonica, Hizikia fusiformis, and Undaria pinnatifida), Rhodophyceae (Porphyra tenera and Gracilaria verrucosa), and Chlorophyceae (Ulva lactuca). The moisture content (% dry weight) ranged from 11.47% to 13.94%, ash from 19.15% to 26.50%, protein from 5.08% to 15.44%, lipid from 2.75% to 4.43%, and dietary fiber from 36.84% to 52.98%. C14:0, C16:0, C18:0, C16:1, C18: 1n-3, C18:2n-6, C18:3n-6, C20:4n-6, and C20:5n-3 represented the predominant proportions of fatty acids. Interestingly, docosahexaenoic acid (C22:6n-3, DHA) was either not found or only detected in trace amounts in the analyzed seaweeds. The levels of n-3 fatty acid were higher than other polyunsaturated fatty acids, and the n-6/n-3 ratio was very low. These results indicate that seaweed inhabiting Korean coastal areas will be beneficial to human health.

• Korean Journal of Food Science and Technology
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• 제17권4호
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• pp.283-288
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• 1985

Fermented big eyed herring. Harengula zunasi, and slimy, Leiognathus nuchalis, were widely used and contributed in diet of people in southern coast of Korea. In this paper, in order to elucidate the taste compounds of fermented big eyed herring and slimy, the nucleotides and their related compounds, free amino acids, TMAO, betaine, total creatinine, and minerals were analyzed. In fermented big eyed herring, lysine, alanine, leucine, isoleucine and valine were dominant holding 88.6% of the total free amino acids while alanine, leucine, isoleucine and lysine in fermented slimy were dominant holding 84.4% of total free amino acids. In the nulceotide and their related compounds, hypoxanthine was the major component in both samples. The contents of betaine, TMA and total creatinine were 99.7mg%, 24.2mg% and 432.8mg% in fermented big eyed herring, 107.6mg%, 19.5mg% and 258.8mg% in fermented slimy, while the contents of TMAO appeared trace in both samples. In the minerals of both samples Na and Ca were dominant holding 37,471-45,100.8ppm, 14,117.1-19,948.1ppm, respectively. From the omission test and chemical analysis, it is concluded that the major taste compounds of fermented big eyed herring and slimy were amino acids such as alanine, lysine, leucine and isoleucine. Minerals, nucleotides and their related compounds, betaine and total creatinine acted as an auxiliary role in taste of both fermented samples.