• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.180-186
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• 2004

The presence of noise in speech signals degrades the performance of recognition systems in which there are mismatches between the training and test environments. To make a speech recognizer robust, it is necessary to compensate these mismatches. In this paper, we studied about an improvement of stochastic feature extraction based on band-SNR for robust speech recognition. At first, we proposed a modified version of the multi-band spectral subtraction (MSS) method which adjusts the subtraction level of noise spectrum according to band-SNR. In the proposed method referred as M-MSS, a noise normalization factor was newly introduced to finely control the over-estimation factor depending on the band-SNR. Also, we modified the architecture of the stochastic feature extraction (SFE) method. We could get a better performance when the spectral subtraction was applied in the power spectrum domain than in the mel-scale domain. This method is denoted as M-SFE. Last, we applied the M-MSS method to the modified stochastic feature extraction structure, which is denoted as the MMSS-MSFE method. The proposed methods were evaluated on isolated word recognition under various noise environments. The average error rates of the M-MSS, M-SFE, and MMSS-MSFE methods over the ordinary spectral subtraction (SS) method were reduced by 18.6%, 15.1%, and 33.9%, respectively. From these results, we can conclude that the proposed methods provide good candidates for robust feature extraction in the noisy speech recognition.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.5
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• pp.267-273
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• 2003

We have investigated the effect on inducing substate(s) of positively charged residues replaced in position 172 of the second transmembrane domain in murine inward rectifier potassium channels, formed by stable or transient transfection of Kir2.1 gene in MEL or CHO cells. Single channel recordings were obtained from either cell-attached patches or inside-out patches excised into solution containing 10 mM EDTA to rule out the effect of $Mg^{2+}$ on the channel gating. The substate(s) could be recorded with all mutants D172H, D172K and D172R. The unitary current-voltage (I-V) relation was not linear with D172H at $pH_i$ 6.3, whereas the unitary I-V relation was linear at $pH_i$ 8.0. The relative occupancy at $S_{LC}$ was increased from 0.018 at $pH_i$ 8.0 to 0.45 at $pH_i$ 5.5. In H-N dimer, that was increased from 0.016 at $pH_i$ 8.0 to 0.23 at $pH_i$ 5.5. The larger the size of the side chain or $pK_a$ with mutants (D172H, D172K and D172R), the more frequent the transitions between the fully open state and substate within an opening. The conductance of the substate also depended upon the pKa or the size of the side chain. The relative occupancy at substate $S_{LC}$ with monomer D172K (0.50) was less than that in K-H dimer (0.83). However, the relative occupancy at substate with D172R (0.79) was similar to that with R-N dimer (0.82). In the contrary to ROMK1, positive charge as well as negative charge in position 172 can induce the substate rather than block the pore in murine Kir2.1. The single channel properties of the mutant, that is, unitary I-V relation, the voltage dependence of the mean open time and relative occupancy of the substates and the increased latency to the first opening, explain the intrinsic gating observed in whole cell recordings.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1744-1752
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• 2013

We investigated the protective effect of UVB inducing photodamage from mulberry extract (ME) and Lithospermum erythrorhizon extract (LE). The contents of total anthocyanin and shikonin as a color compound of ME and LE were 4.92 mg/g and 9.58 mg/g, respectively. The electron donating ability and superoxide radical scavenging activity of ME were 84.32% and 76.34%, respectively. The oxygen radical absorbance capacity of the ME ($545.37{\mu}moles$ TE/g) was higher than LE ($427.18{\mu}moles$ TE/g). MMP-1 production in the HS68 cells were exposed to UVB suppressed by treatment with $200{\mu}g/mL$ of ME (68.6%) and LE (32.7%). ME and LE were applied to a skin aging mouse model, which was induced by the irradiation of UVB to the backs of hairless mice. The value of skin erythema index, wrinkle depth and thickness, epidermis thickness, and collagenous fiber damage in the experiment groups (MEL: ME 3%, MEM: ME 5%, MEH: ME 7%, LEL: LE 3%, LEM: LE 5%, LEH: LE 7%) were remarkably reduced than in the control group (only UVB exposure group), while water capacity increased. The level of total wrinkles depth in the skin was decreased to be 30% of the control group by MEH and LEM. These results suggest that ME and LE are useful cosmetic materials for skin protection against UVB-inducing.

• The Korean Journal of Financial Management
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• v.7 no.1
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• pp.1-20
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• 1990

In most of studies on market efficiency, the stability of risk measures and the normality of residuals unexplained by the pricing model are presumed. This paper re-examines stock splits, taking the possible violation of two assumptions into accounts. The results does not change the previous studies. But, the size of excess returns during the 2-week period before announcements decreases by 43%. The results also support that betas change around announcements and the serial autocorrelation of residuals is caused by events. Based on the results, the existing excess returns are most likely explained as a compensation to old shareholders for unwanted risk increases in their portfolio, or by uses of incorrect betas in testing models. In addition, the model suggested in the paper provides a measure for the speed of adjustment of the market to the new information arrival and the intensity of information contents.

• Textile Coloration and Finishing
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• v.27 no.1
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• pp.70-79
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• 2015

To establish the optimal conditions for the manufacture of high absortive cellulose film(CF) originated from Styela clava tunic(SCT), the physicochemical properties included absorption was measured in CFs prepared under the various conditions. The highest absorption was observed for SCT-CF20 prepared from the cellulose solution dissolved at $80^{\circ}C$ for 20min, although the filtration treatment did not induce any significance alteration. Also, the absorption was higher in SCT-CF20-F prepared by the freeze drying than SCT-CF20-N(ambient air drying) and SCT-CF20-H(heat drying). The addition of porogen($NaHCO_3$) induced an increase of absorption in SCT-CF20-PF relative to SCT-CF20-F, while the number of interconnected porous structures was enhanced in SCT-CF20-PF. Furthermore, a high level of SK-MEL-2 cells viability was observed in SCT-CF20-PN and SCT-CF20-PF cultured group. These results show that SCT-CF may have high absorption and biocompatibility when prepared from SCT cellulose solution dissolved at $80^{\circ}C$ for 20min after addition of porogen and then subjected to freeze drying.

• Korean Journal of Breeding Science
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• v.42 no.4
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• pp.397-406
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• 2010

Field screening method has been commonly used for purity test of $F_1$ hybrid seeds in melon and oriental melon. However, as this method takes a lot of time and cost, molecular marker-based purity test is necessary. To develop molecular markers for purity test, thirty pairs of SNP (single nucleotide polymorphism) primers were obtained from melon EST sequences, and 10 polymorphic markers showing HRM (high resolution melting) polymorphisms between parents of two melon cultivars and one oriental melon cultivar were selected. Blind tests were performed to validate usefulness of the selected markers for purity test. Blind test results showed that HRM genotypes were matched with the expected identity of individual sample, $F_1$ hybrid, male or female parents. Three HRM-based SNP markers were converted to CAPS markers for general use which is favor to breeders. We expect that SNP markers developed in this study will be useful for purity test of $F_1$ hybrid seeds in melon and oriental melon.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.349-357
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• 2005

New antioxidative substances for cosmeceuticals were screened from natural resources such as microbial metabolites, mushrooms, and medicinal plants. Four antioxidants were isolated from the fungal metabolite of Eupenicillium shearii and their structures were determined to be new phenolic compounds. The compounds were designated as melanocins A, B, C, and D. Melanocins $A{\sim}D$ exhibited free radical scavenging activity on DPPH and superoxide with $EC_{50}$ values of $21{\sim}94\;and\;7{\sim}84{\mu}M$, respectively, which were stronger activity than those of ${\alpha}-tocopherol$ and BHA. Melanocin A showed anti-wrinkle effects on the UV-irrated hairless mouse skin. A novel hispidin antioxidative compound designated as inoscavin A was isolated from the fruiting body of the mushroom, Inonotus xeranticus. Inoscavin A scavenged superoxide radical with $EC_{50}$ values of $0.03{\mu}g/mL$, and inhibited rat liver microsomal lipid peroxidation with $EC_{50}$ values of $0.3{\mu}g/mL$. Benzastatins $A{\sim}G$, the novel antioxidants isolated from the culture of Streptomyces nitrosporeus showed potent lipid peroxidation inhibitory activity with $EC_{50}$ values of $3{\sim}30{\mu}M$. A cyclopentene compound with strong hypopigmentary effect was isolated from the fungal metabolite of Penicillium sp. and identifed as terrein. Terrein significantly reduced melanin levels in a melanomacyte cell line, Mel-Ab. It showed 10 times stronger activity than kojic acid, but exhibited no cytotoxic effect even in $100{\mu}M$. It was suggested that terrein reduced melanin synthesis by reducing tyrosinase production by MITF down-regulation.

• Journal of the Korean earth science society
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• v.29 no.2
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• pp.189-203
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• 2008

Microcomputer Based Laboratory (MBL), by offering accurate and effective data collection and real-time graphs, enables students to reduce experiment time and, thereby, have deeper discussions concerning experimental results. This helps to emphasis the essential aspect of scientific inquiry; the process communication. Therefore, this study examined secondary school earth science MBL lessons with regards to the five basic aspects of scientific inquiry: "Asking", "Evidencing", "Explaining", "Evaluating" and "Communicating". It then investigated the level of argumentative communication between the students and teachers and also among the students themselves. For this study, three classroom activities were observed and videotaped, and teaching materials, textbooks and students' notes were collected. The transcribed data were analyzed from the perspective of scientific inquiry level and argument frames. The results showed that the scientific inquiry levels of the three classes were similar, except for the "Communicating" aspect, which appeared in only one episode. "Asking" was carried out by the teacher and then students were directed to collect certain data in the "Evidencing" stage. Furthermore, students were given possible ways to use evidence to formulate explanations and connections through the "Explaining" and "Evaluating" stages. In the argumentation analysis, most argumentative communication was identified as being associated with a given procedure, rather than with any scientific phenomena. In only one episode, did "Communicating" relate directly to any scientific phenomena. It can be concluded, that although MEL places emphasis on communication for authentic scientific inquiry, the environment required for such inquiry and argumentative communication can not be easily created in the classroom. Therefore, in order for authentic inquiry to take place in the MBL classroom, teachers should provide students with the opportunity to develop meaningful argumentation and scaffolding abilities.