• Communications for Statistical Applications and Methods
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• v.21 no.2
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• pp.183-191
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• 2014

We define a multivariate Cauchy distribution using a probability density function; subsequently, a Ferguson's definition of a multivariate Cauchy distribution can be viewed as a characterization theorem using the characteristic function approach. To clarify this characterization theorem, we construct two dependent Cauchy random variables, but their sum is not Cauchy distributed. In doing so the proofs depend on the characteristic function, but we use the cumulative distribution function to obtain the exact density of their sum. The derivation methods are relatively straightforward and appropriate for graduate level statistics theory courses.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.7 s.238
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• pp.861-867
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• 2005

In order to develop oxy-fuel combustor, the Flame length characteristic of $CH_4$ with oxidizer of air and oxygen has been experimentally investigated for tile nozzle diameters of 1.6mm, 2.7mm, 4.4mm and 7.7mm. The structure of $CH_4$ flame with oxidizer of oxygen was sharp in contrast with the $CH_4$ flame with oxidizer of air. The stability of $CH_4$ flame with oxidizer of oxygen was higher than $CH_4$ flame with oxidizer of air. In all $CH_4$ flames with oxidizer of air and oxygen, the flame length were dependent on the flowrate in laminar flame regime, and in turbulent flame dependent on the initial jet diameter. Using correlation equation of Delichatsios, the flame length has been expected exactly for $CH_4$ flame with oxidizer of air, but underestimated for $CH_4$ flame with oxidizer of oxygen. This paper proposed correlation equation of $CH_4$ flame with oxidizer of oxygen.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.399-400
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• 2008

The light efficiency of fringe-field switching (FFS) mode when using a liquid crystal (LC) with positive dielectric anisotropy was found to be dependent on the magnitude of dielectric anisotropy, such that the lower dielectric anisotropy, the higher. We studied out not only light efficiency but also response time according to dependence on the magnitude of dielectric anisotropy. Rising and decay time became fast and slow respectively according to decreasing the magnitude of dielectric anisotropy. This paper investigates electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy dependent on the magnitude of dielectric anisotropy of the LC.

• Korean Journal of Materials Research
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• v.33 no.6
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• pp.229-235
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• 2023

An all-perovskite oxide heterostructure composed of SrSnO₃/Nb-doped SrTiO₃ was fabricated using the pulsed laser deposition method. In-plane and out-of-plane structural characterization of the fabricated films were analyzed by x-ray diffraction with θ-2θ scans and φ scans. X-ray photoelectron spectroscopy measurement was performed to check the film's composition. The electrical transport characteristic of the heterostructure was determined by applying a pulsed dc bias across the interface. Unusual transport properties of the interface between the SrSnO₃ and Nb-doped SrTiO₃ were investigated at temperatures from 100 to 300 K. A diodelike rectifying behavior was observed in the temperature-dependent current-voltage (IV) measurements. The forward current showed the typical IV characteristics of p-n junctions or Schottky diodes, and were perfectly fitted using the thermionic emission model. Two regions with different transport mechanism were detected, and the boundary curve was expressed by ln I = -1.28V - 13. Under reverse bias, however, the temperature- dependent IV curves revealed an unusual increase in the reverse-bias current with decreasing temperature, indicating tunneling effects at the interface. The Poole-Frenkel emission was used to explain this electrical transport mechanism under the reverse voltages.

• Electrical & Electronic Materials
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• v.8 no.2
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• pp.151-157
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• 1995

Frequency-dependent electrical properties of $C_{22}$-Quinolinium(TCNQ) LB films were investigated in a frequency range of 10[Hz]-13[MHz] along a perpendicular direction. The films were heat-treated to understand an electrodynamic response in a temperature range of 20-240[.deg. C]. Frequencydependent dielectric constants show that there are two characteristic dispersions; one is a dispersion occuring near 1[MHz] coming from the orientational polarization of the molecules and the other one is an interfacial polarization effect below 1[kHz] or so when the annealing temperature is above 80 [.deg. C]. The overall frequency-dependent dielectric constant is higher near 80[.deg. C]. It may be due to a softness of the alkyl chains. Several other methods were employed to identify the internal structure change of the films. DSC(differential scanning calorimetry) data of the $C_{22}$-Quinolinium(TCNQ) molecules shows that there is an endothermic process near 110[.deg. C] and a weak exothermic process near 180[.deg. C]. While the endothermic process is related to a disordering of the alkyl chains, the exothermic process seems to be due to a chemical structure change of the TCNQ molecules. Thickness measurement by ellipsometry shows that there is a thickness drop near 100[.deg. C], and the thickness above 120[.deg. C] becomes around 20[%] of the room-temperature value.lue.

• BMB Reports
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• v.51 no.1
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• pp.1-2
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• 2018

Positive selection on a new beneficial mutation generates a characteristic pattern of DNA sequence polymorphism when it reaches an intermediate allele frequency. On genome sequences of African Drosophila melanogaster, we detected such signatures of selection at 37 candidate loci and identified "sweeping haplotypes (SHs)" that are increasing or have increased rapidly in frequency due to hitchhiking. Based on geographic distribution of SH frequencies, we could infer whether selective sweeps occurred starting from de novo beneficial mutants under simple constant selective pressure. Single SHs were identified at more than half of loci. However, at many other loci, we observed multiple independent SHs, implying soft selective sweeps due to a high beneficial mutation rate or parallel evolution across space. Interestingly, SH frequencies were intermediate across multiple populations at about a quarter of the loci despite relatively low migration rates inferred between African populations. This invokes a certain form of frequency-dependent selection such as heterozygote advantage. At one locus, we observed a complex pattern of multiple independent that was compatible with recurrent frequency-dependent positive selection on new variants. In conclusion, genomic patterns of positive selection are very diverse, with equal contributions of hard and soft sweeps and a surprisingly large proportion of frequency-dependent selection in D. melanogaster populations.

• Korean Journal of Health Education and Promotion
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• v.6 no.2
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• pp.4-22
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• 1989

This study aims to explore the relationship between housewives' health KAP level and the physical health of families. The data used in this study are obtained from the Last Evaluation Program of the National Note for Health surveyed in July, 1989. The respondents for this study are 770 housewives residing in Chunan and Buan. The reason why this study focus on KAP level of housewives is to find out whether a housewife as a emotional supporter contributes to the physical health of her families. A housewife gives her families emotional satisfaction insteade of economic satisfaction. So she has the most interest in family health among the members of her family. Therefore, housewife's KAP level will influence her family health. The independent variables chosen for the analysis are the general characteristic variables and KAP level. And the dependent variable is the physical health of families which excluded psychosocial one. This level of family health includes weight for family health and seriouseness of disease. The result of this study was summarized as follows. (1) KAP level was significantly correlated with variables which have mainly the socioeconomic characteristics. The variables were: area of residence, education level occupation, self assessment on wealth, and exposure to mass communication. (2) In the analysis of relationship between the general characteristic variables and family health, family health was significantly correlated with almost all variables. The variables were: Presence of the aged, Health status, Experience in disease, Self assessment on health, No. of families, Occupation, Education level, Self assessment on wealth, Concern on health, and Exposure to mass communication. (3) In the analysis of relationship between family health and KAP level, family health was not significantly correlated with KAP level but. (4) Also in the stepwise regression analysis, the general variables account for about 32.1 percent of the variance in the dependent variable, family health. The variable with the greatest explanatory power was presence of the aged. On the contrary, KAP level explain about 0.4 percent of the variance in the dependent variable. In sum, the study shows that housewives' health KAP level has relatively weak relationship with the physical health of families

• Journal of Korean Academy of Nursing
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• v.24 no.3
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• pp.364-376
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• 1994

This study was initiated to find the characteristic awareness of disease in Korean culture and then, with its applying to psychological nursing, to help cancer victims cope with their disease. Research period was from Dec. 1, 1989 to Aug.3, 1992. The research method, while the method of face-to-face interview with 33 cancer victims were mainly adopted, was to identify the causal perception through analyses of literature and traditional sayings deeply rooted in Korean culture. The causal perceptions were differentiated into 4 sections, which apply to 32 cancer victims with Q-sorting. Be-ing coded into grades from 1 to 9, the data were analyzed with the aid of Quanal program on PC ; in analyzing Q-factor principal component analysis method was used. The results were revealed as follows : 1. Subject victims owe their disease to 1) the omnipotent and animating powers in Shamanism rooted in Korean culture, 2) their intimate persons, i.e. their husband, wife, children, or other fellows ameng their groups. 3) victims themselves, and 4) nowhere, for they thought the disease is the struggle with their own self. 2. In Q-methodology analysis, cancer victims are categorized into 5 types. The first type, self-mastery type, consisting of 11 subjects, has the characteristic of overcoming their disease with their own strong will or by the help of the Omnipotent God, which is estimated to be the ideal type to cope with the disease. The second type, omnipotent & animating powers-dependent type, consisted of 7 subjects, who have the causal perception of traditional shamanism. The third type, intimate person-dependent type, consisted of 4, all of whom are women and whose causal perception has the characteristic of the their complains about each member of their family, espectially about their husband. The fourth type, fate-recipient type, was the com-plex form of the first and the second types. It consisted of 6 subjects, to whom cancer had meant bad fate coming on them but had to be overcome by their strong will. The fifth type, personal type, consisted of 4, whose causal perception is toward themselves personality It is hoped that the study provide the chance of developing nursing intervention to help cancer victims accept and overcome their disease as their own reality instead of attributing to anyone or any-thing else.

• BMB Reports
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• v.44 no.10
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• pp.692-697
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• 2011

To investigate the pathways of oxidoreductases in plants, 2 key components in thioredox systems i.e. thioredoxin h (Trx h) and NADPH-dependent thioredoxin reductase (NTR) genes were first isolated from tomatoes (Solanum lycopersicum). Subsequently, the coding sequences of Trx h and NTR were inserted into pET expression vectors, and overexpressed in Escherichia coli. In the UV-Visible spectra of the purified proteins, tomato Trx h was shown to have a characteristic 'shoulder' at ~290 nm, while the NTR protein had the 3 typical peaks unique to flavoenzymes. The activities of both proteins were demonstrated by following insulin reduction, as well as DTNB reduction. Moreover, both NADPH and NADH could serve as substrates in the NTR reduction system, but the catalytic efficiency of NTR with NADPH was 2500-fold higher than with NADH. Additionally, our results reveal that the tomato Trx system might be involved in oxidative stress, but not in cold damage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.577-582
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• 2007

The plasma display panel is an image expression display using gas discharge plasma. However, gas discharge characteristics vary with temperature as gas discharge is sensitive to temperature. The discharge time lag extends a lot in low temperature and it is known as the cause which hinders high speed addressing which is essential for the size enlargement of the panel. Accordingly this research aims at identifying the temperature-dependent discharge characteristic. The lower temperature becomes, the longer addressing discharge time lag becomes. Particularly the statistical time lag extends much in low temperature. The increasing of electric field shortens discharge time lag in low temperature. Also, when priming particles are sufficiently supplied, stable discharge can be performed regardless of the influence of temperature.