• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.1-13
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• 2021

Previous studies have found the significant adverse effects of coronavirus disease 2019 (COVID-19) on stock returns and volatility. The effects varied with the confirmed cases and deaths. However, the extent of the effects have never been measured exactly. This study proposes a measurement model for the COVID-19 effects. In the proposed model, stock returns in the COVID-19 period are weighted averages of pre-COVID-19 normal returns and COVID-19-induced returns. The effects are measured by the contributing weights of the COVID-19-induced returns. Kalman filtering is used to estimate the model for the world and Chinese markets, in combination with 10 markets - five most affected countries (United States, India, Brazil, Russia, and France) and five best recovering countries (Hong Kong, Australia, Singapore, Thailand, and South Korea). The sample returns are daily, obtained from the closing Morgan Stanley global investable market indexes. The full period is from September 24, 2018, to October 30, 2020, whereas the COVID-19 period is from November 18, 2019, to October 30, 2020. The contributing weights are significant and close to 100% for all markets. The COVID-19-induced returns replace the pre-COVID-19 normal returns; they are negatively auto-correlated and highly volatile. The COVID-19-induced returns are new normal returns in the COVID-19 period.

• The Korean Journal of Food And Nutrition
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• v.36 no.4
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• pp.236-243
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• 2023

The purpose of this study was to investigate the effects of sterilization, storage period and washing yuzu, according to the washing method, during the storage period. The results showed that the fungus size increased as the storage period increased, and no mold occurred in the yuzu washed with ozone water until 20 days. After 30 days of storage, a mold of 124.1±13.9 mm² was observed. The no-treatment sample had a fungus of 814.5±72.8 mm² in size on day 0 and the fungus the largest fungus was 6,362±636.7 mm² on day 30. In the case of water treatment, the fungus was 286.4±31.5~4,836.4±484.6 mm² in size. The results of the study confirmed that washing yuzu with ozone water has a sterilizing effect.

• Earthquakes and Structures
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• v.24 no.5
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• pp.377-391
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• 2023

The high seismic risk has once again revealed in Türkiye with two major earthquakes that occurred on 06.02.2023, which took its place among the most destructive earthquakes in the last century. Totally, 65 earthquakes that occurred in the historical period in Türkiye were taken into account within the scope of this study. The seismic parameters were compared by considering the last two earthquake hazard maps for the epicenters of these earthquakes. Earthquake Intensity (I) of historical earthquakes were converted to Peak Ground Acceleration (PGA) by using suggested relations. Structural analyzes were performed for a sample reinforced-concrete building by using the obtained PGA's and predicted PGA's in the last two earthquake hazard maps. In the structural analysis, two different material groups such as low (C12-S220) and normal (C25-S420) were selected. As the material strength increased, the period value decreased, while the seismic capacity and stiffness increased. It has been determined that there are differences between the measured and proposed seismic risks for some earthquakes, and as a result, there are significant differences between the expected target displacement values from the structures. Therefore, it will not be possible to estimate the damage and to determine the building performance realistically. The main purpose of the study is to reveal whether the earthquake risk is adequately represented on seismic and structural parameters.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1230-1236
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• 2004

This study was conducted to investigate the changes in physical properties of the Neungee (Sarcodon aspratus) during dehydration and rehydration. The drying of the sample was completed within 4 hours at 5$0^{\circ}C$ with the air velocity of 1.5 m/s. The reduction in the thickness of the sample were two-fold compared with those in the surface area of the sample. During the drying period, the values of compression distance, break down, deformation rate, distortion, alleviation rate and softness decreased, whereas the values of hardness and alleviation time increased. However, the values of surrender were not changed. The color of the sample during the drying was changed to black with decreased L, a, and b values. The rehydration rate increased rapidly during first 60 min and remained constant after that. The recovery ratio after rehydration of the dried sample was about 30％ and the rheological properties recovered about 44％.

• Journal of the Korean Society of Food Culture
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• v.33 no.1
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• pp.36-47
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• 2018

In this study, pH, $^{\circ}Brix$, salt concentration, sodium content, color, hardness, and sensory evaluations were measured during storage at low temperatures for 21 days after making tongue sole Jangajji with different types of Gochujang sauces. The pH was higher than those of samples not containing Maesil fermented liquor at all storage periods. The $^{\circ}Brix$ of the Maesil fermented liquor added samples was higher than that of the samples not added at the early stages of storage. On the other hand, there was no significant difference between the samples with and without Maesil fermented liquor at the later stages of storage. The sodium content was lower than that of the samples not containing Maesil fermented liquor. The lightness (L) was lower in the early stages of storage than those of the Maesil fermented liquor. In the late stage of storage, however, the lightness was higher than those of the samples not containing Maesil fermented liquor. The redness (a) of the GRWO sample group showed the highest value at all storage periods compared to the other sample groups. The yellowness (b) of the GRWO sample group was high at the early stages of storage. On the $21^{st}$ day of storage, however, the GRW sample group was significantly higher (p<0.01). The hardness results showed that the value of the later storage period was lower than that at the initial storage stage. The sensory evaluation showed that the Maesil fermented liquor reduced the spicy, salty, bitter, and unpleasant taste. As a result of the acceptance test, the GRWO and GRW samples were evaluated as the acceptance group with color, aroma, texture and overall acceptability compared to the brown rice Gochujang sample group.

• Survey Research
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• v.11 no.1
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• pp.19-41
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• 2010

Although it is possible to provide statistically reliable estimators of the entire population parameters based on each independent rolling sample, estimators of the small areas may not have the required statistical efficiency. Thus, in general, small area estimators are calculated based on the combined rolling sample after entire rolling sample survey is finished. In this study, we considered the construction of weights that is necessary in the analysis of the combined rolling sample. Unlike the past studies that provided the empirical results for the corresponding specific rolling sample survey, we considered linear models that depends only on design variables and rolling period and provided the corresponding Best Linear Unbiased Predictor(BLUP). Through a simulation study, we proposed the estimators for the population parameters that are robust to model failure and the BLUP under the assumed model. The results are applied to the 4th Korea National Health and Nutrition Examination Survey.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1068-1073
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• 2004

Response surface methodology (RSM) was used to monitor characteristics of hot water extracts from Hericium erinaceus. A central composite design was applied to investigate the effects of independent variables, extraction temperature (X$_1$), sample ratio (X$_2$) and extraction time (X$_3$) on dependent variables such as soluble solid (Y$_1$), total phenols (Y$_2$), crude protein (Y$_3$) and electron donating ability (Y$_4$) of the extracts. As the sample ratio increased, the soluble solid content increased, while extraction temperature played a minor role. As a whole total phenols and crude protein contents increased with increasing the sample ratio. Electron donating ability increased in proportion to extraction temperature and sample ratio, which didn't increase at certain period. Then ranges of optimum extraction conditions for maximized physicochemical properties were 91.5∼96.5$^{\circ}C$ in extraction temperature and 3.5∼4.2 g/100 mL in sample ratio. Predicted values at the optimized conditions were coincident with experimental values.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.562-565
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• 2013

A new variable rate speech coding technique is proposed. The method is based on the observation that the speech signal approximately looks linear for a very short period of time. The information transmitted is the location and data value of inflection points. If the distance between the inflection points is large, the mid point location and its data value are also delivered. Thus, the encoder transmits both the location and the data value for the inflection samples, but the location only for the non-inflection points. The location information is expressed using one bit for each sample, 0 for non-inflection and 1 for inflection point. At the receiver, using the interpolation, the decoder estimates the untransmitted sample values for non-inflection locations from the received sample values for the inflection samples. With 50 % of computational cost of the existing CVSD delta modulation, the proposed method is expected to achieve the data rate of 36 to 38 kbps and the SNR of 10 to 13 dB.

• Journal of Korean Academy of Nursing
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• v.13 no.1
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• pp.34-41
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• 1983

This study was concerned with the investigation of the relationship between the degree of family incongruence about family environment and the occurrence of juvenile delinquency using Family Environmental Scale (F.E.S) designed by Rudolf Moos. The study employed the control group design using the interview and questionnaire through home visiting. The control group sample consisted of 44 families from a middle socioeconomic S Dong community setting and the experimental group sample consisted of 30 families of juve nile from Juvenile Training School in Seoul, Total sample size was 321. Data for this study was collected over a period of three months from the end of Nov. 1982 to the beginning of Feb. 1983, after pretest. To analize the data, t-test was used. The result of this study was as follows; 1. The experimental groups' incongruence score was 18.8598 as compared to the control groups' score of 14.8598. The differences were statistically significant at .001 level, and the hygothesis was supported. 2. The experimental group had higher incongruence scores as compared to the control group of three dimensions, the differences were statistically significant at .05 level. The experimental group had higher incongruence scores than the control group on 6 subscales, namely, cohesion, expressiveness, conflict, achievement orientation, moral-religious emphasis and organization. The differences were statistically significant at. 05 level.

• The Korean Journal of Ecology
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• v.15 no.4
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• pp.329-335
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• 1992

Bionomics of diplopodes was studid near chongyongchi in the chiri mountains from sept. 1990 to dec. 1991 by surveying 10 sample sites at 12 occasions. During this period 13 species of diplopodes from 11 genera, 8 families, and 6 orders were collected. Species were more diversed under quercus mongolica followed by quercus serrata and pinus densiflora sp. epenerchodus koreanus bifidus, and e. k. koreanus were found in all sample sites and these 6 species have been reported to be distributed throughout south korea. yamasinaium sp., riukiaria semicirculalis, parafontaria koreanus, and sicotanus eurygaster were found only under quercus mongolica community and postulated to be related to diet meanwhile other enviromental factors such as temperature, soil ph, and altitude should be taken into consideration. Species diversity index was higher at altitude 700m followed by at 900m, 1, 000m, 800m, 600m, 500m, 1, 100m, 400m, 300m, and 1, 200m in discending order likely due to the enviromental factors such as climatic and edaphic affects, disturbance by human, and degree of floral diversity. Species similarity index was highest 0.78 between altitude 500m and 600m sample sites could be grouped into 3, namely first 300m, 400m, second 500m, 600m, 700m, 1, 000m, 800m, 900m, and third 1, 100m, 1, 200m.