• Asia-Pacific Journal of Business
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• v.14 no.4
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• pp.319-330
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• 2023

Purpose - The purpose of this paper is to examine the connectedness between categorical economic policy uncertainty (monetary, fiscal, trade and foreign exchange policy uncertainty) indexes and option-implied volatility index in Korea, Japan and the US. Design/methodology/approach - This paper employs the Diebold-Ylmaz (2012) model based on a VAR and generalized forecast error variance decomposition. This paper also conducts regression analyses to investigate whether the volatility indexes are explained by categorical policy uncertainty indexes. Findings - First, we find the total connectedness is stronger in Korea and Japan relative to the US. Second, monetary, fiscal, and foreign exchange policy uncertainty indexes are connected to each other but trade policy uncertainty index is not. Third, the volatility index in Japan and the US is mainly associated with monetary policy uncertainty while the volatility index in Korea is explained by fiscal policy uncertainty index. Research implications or Originality - To our knowledge, this is the first study to investigate the connectedness among categorical policy uncertainty indexes and the volatility index in Korea, Japan, and the US. The empirical results on the connectedness suggest that transparent policy and communication with the market in one type of policy would reduce the uncertainty in other policies.

• Asia-Pacific Journal of Business
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• v.15 no.2
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• pp.223-236
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• 2024

Purpose - The purpose of the paper is to empirically investigate the asymmetric adjustment of loan and deposit interest rates among banks and non-bank depository institutions. Design/methodology/approach - We construct a VAR model using time series data comprising loan and deposit interest rates of banks and non-bank depository institutions, along with the call rate. Based on this model, we conduct impulse-response analysis and variance decomposition to investigate the dynamic relationship between the interest rates. Findings - In the case of banks and credit unions, the responses of deposit rates to the call rate are larger than the responses of loan rates, and we cannot find evidence of non-linear responses. In the case of savings banks, the responses of loan rates to the call rate are larger than the responses of deposit rates. The responses of loan rates to a positive call rate shock are statistically significant, while the responses of loan rates to a negative call rate shock are not statistically significant. Research implications or Originality - This study differs from previous research in that it examines the asymmetric response of loan and deposit rates of both banks and non-bank financial institutions to changes in the call rate. The implications for the impact of these findings on the financial system and income inequality are presented.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.657-664
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• 2011

The plant community of water`s edge was investigated using the methodology of the Z-M school of phytosociology, from March to October, 2008, 2011. The results were obtained as follow ; hygrophyte hydrophye of 2008 year of this area consist of 38 taxa : 1 varieties, 37 species, 31 genera, 21 families and 14 orders, hygrophyte hydrophye of 2011 year of this area consist of hygrophyte 15 species, 13 species were reduced by approximately 13.33%. And emerged hydrophyres did not show a change. 9 species, 4 species of Floating-Leaved hydrophyres 55.56%, Submerged hydrophyres of the 4 species, 1 species, 75%, Free-Floating hydrophyres remarkable I the 3 species was reduced to 33.33%, respectively. Plants Community of the water's edge was classified into 16 communities as follows; (Leersia japonica community, Spirodela polyrhiza community, Miscanthus sacchariflorus community, Hydrocharis dubia community, Zizania latifolia community, Paspalum distichum var. indutum community, Leersia japonica-Hydrocharis dubia community, Salix glandulosa community, Trapa japonica community, Humulus japonicus community, Nelumbo nucifera community, Carex dimorpholepis community, Salix koreensis community, Trapa japonica-Spirodela polyrhiza community, Persicaria thunbergii). Higher in 2011 than in 2008, the ratio was reduced to Leersia japonica community. Between July-August by a sudden change in the rate of water storage changes in vegetation are thought to have appeared.

• Korea Real Estate Review
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• v.24 no.1
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• pp.39-52
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• 2014

This study examines the degree of global co-movement & spillover effect among the housing price of ten major countries of OECD including Korea, based on the 3 hypothesis. The data used in this study is quarterly house price index of OECD countries from 1975 to 2012. VAR model is used to analyze the co-movement, and Granger causality methodology is used for the analysis of Spillover Effect. It is found that entire period of study is that the global house prices showed the co-movement, but the coefficient was weak. Since 2008 global financial crisis, the co-movement increased significantly and the adjusted R-square of this model increased 78% compared to the entire period (1975-2012). In general, all hypotheses in this study were significant, and the common shock hypothesis were most significant. In case of Korea, the degree of co-movement was weak compared to the other countries and spillover effect was independent since 2008.

• The Journal of Industrial Distribution & Business
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• v.10 no.9
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• pp.53-60
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• 2019

Purpose - The objective of this paper is to discover if there exists a relationship between the economic index and distribution industry index in Korean. Because of the distribution industry boom in the recent years, a lot of interest in the relationship between the economic index and distribution industry index in Korean and the economy has been generated. This article examine on the mutual influence between economic index and distribution industry index in Korean. Research design, data, and methodology - For this purpose, we use the vector-auto regression model, impulse response function and variance decomposition of the economic index and distribution industry index, Granger causality test using weekly data on the economic index and distribution industry price index in korea. The sample period is covering from January 2, 2010 to August 31, 2019. The VAR model can also be linked to cointegration analysis. Cointegration Analysis makes possible to find a mechanism causing x and y to move around a long-run equilibrium (Engle and Granger, 1987). This equilibrium means that external shocks may separate the series temporarily at any particular time, but there will be an overall tendency towards some type of long-run equilibrium. If variables are found to have this tendency they are said to be cointegrated and a long-run relationship between these series is established. These econometric tools have been applied widely into economics and business areas to analyze intertemporal linkages between different time series. Results - This research showed following main results. First, from the basic statistic analysis of the economic index and distribution industry index in Korean, the economic index and the distribution industry index in korea have unit roots. Second, there is at least one cointegration between the economic index and distribution industry index in Korean. Finally, the correlation between of the economic index and the distribution industry index in korea is (+) 0.528876. Conclusions - We find that the distribution industry price index Granger cause the economic index in korea. As a consequence, the distribution industry index affect the economic index in Korean. The distribution industry index to the economic index is stronger than that from the economic index to the distribution industry index.

• Journal of Electrical Engineering and Technology
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• v.5 no.1
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• pp.116-128
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• 2010

Modeling of the three phase electric arc furnace and its voltage flicker mitigation are the purposes of this paper. For modeling of the electric arc furnace, at first, the arc is modeled by using current-voltage characteristic of a real arc. Then, the arc random characteristic has been taken into account by modulating the ac voltage via a band limited white noise. The electric arc furnace compensation with static VAr compensator, Thyristor Controlled Reactor combined with a Fixed Capacitor bank (TCR/FC), is discussed for closed loop control of the compensator. Instantaneous flicker sensation curves, before and after accomplishing compensation, are measured based on IEC standard. A new method for controlling TCR/FC compensator is proposed. This method is based on applying a predictive approach with closed loop control of the TCR/FC. In this method, by using the previous samples of the load reactive power, the future values of the load reactive power are predicted in order to consider the time delay in the compensator control. Also, in closed loop control, two different approaches are considered. The former is based on voltage regulation at the point of common coupling (PCC) and the later is based on enhancement of power factor at PCC. Finally, in order to show the effectiveness of the proposed methodology, the simulation results are provided.

• Journal of Korea Trade
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• v.24 no.4
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• pp.1-17
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• 2020

Purpose - Since China has been South Korea's biggest export destination, uncertainty shocks originating from it would influence South Korea's exports. This paper evaluates the effects of China's economic policy uncertainty on Korea's exports to explore the transmission channels. Design/methodology - Incorporating endogeneities and nonlinearities, this study employs a quarterly time-varying parameters vector autoregressive model to investigate the relationships between China's economic policy uncertainty and Korea's exports, where the overparameterization due to time-varying specifications is overcome by a novel stochastic model specification search framework. According to previous theoretical studies, this paper assesses two channels, demand shock channel and exchange rate channel, through which foreign uncertainty affects Korea's exports. This paper identifies the primary drivers of Korea's aggregate exports and analyzes the rationales for the time-variant impacts of China's economic policy uncertainty on Korea's exports to China. Findings - Our empirical results reveal that Korea's aggregate exports are less responsive to China's economic policy uncertainty shocks and significantly move together with global demand. In contrast, its bilateral exports to China are highly responsive in a negative and time-variant way. Moreover, Chinese investment is an important channel through which China's economic policy uncertainty affects Korea's exports to China after 2010. Further, the time-variant effects of China's economic policy uncertainty on Korea's exports to China are related to changes in China's foreign trade policies, global economic conditions, and China's degree of economic freedom. Originality/value - Few previous studies touch the effects of external uncertainty shocks on South Korea's exports. This paper attempts to fill this gap and explicitly investigate the impacts of China's economic policy uncertainty on Korea's exports from a time-varying perspective. As Korea is an export-oriented economy, this study provides insights for the Korean government to understand the transmissions of external uncertainty better.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.195-203
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• 2021

Aureobasidium pullulans, a black yeast, produces pullulan, a linear α-glucan composed of maltotriose repeating units linked by α(1→6)-glycosidic linkages. Pullulan can be widely used in food, cosmetic, and biotechnology industries. In this study, we isolated eight strains of A. pullulans from Forsythia koreana, Magnolia kobus DC., Spiraea prunifolia var. simpliciflora, Cornus officinalis, Cerasus, and Hippophae rhamnoides. Among them, A. pullulans MR was selected as the best pullulan producer. The effects of a carbon source, a nitrogen source, and pH on pullulan production were examined. The optimal cultivation conditions for pullulan production by A. pullulans MR were determined by response surface methodology as 15% sucrose, 0.4% soy peptone, and an initial pH of 7 at 26℃. Under these conditions, the predicted pullulan production was 47.6 g/L, which was very close to the experimental data (48.9 g/L).

• Korean Journal of Environment and Ecology
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• v.38 no.3
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• pp.293-309
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• 2024

This study was conducted to provide basic data on the structure of the Carpinus turczaninowii community and the characteristics of the habitat environment for ex situ conservation. To identify the current ecological environment, 27 plots (each measuring 100m²) were selected for analyzing the detailed structure of plant communities in Anmyondo Isl.(Jungjangri San 14-217), Hwanggumsan Mt., Gayasan Mt.(Wonhyobong) and Palbongsan Mt.. The research methodology employed in this study was qualitative analysis. The TWINSPAN classification yielded a total of seven distinct communities. Group I represents the C. turczaninowii - Quercus mongolica community, Group II represents the C. turczaninowii - Pinus densiflora community, Group III represents the C. turczaninowii - P. densiflora community, Group IV represents the C. turczaninowii - Q. mongolica community, Group V represents the C. turczaninowii - Q. variabilis community, Group VI represents the C. turczaninowii - Prunus serrulata Lindl. var. pubescens community, and Group VII represents the C. turczaninowii - Styrax japonicus community. The species diversity ranged from 0.8056 to 1.1568, the importance value ranged from 0.1214 to 0.3024, and the similarity index ranged from 9.37% to 36.36%. Based on the correlation analysis of six environmental factors for the seven communities using RDA ordination, the results indicate that on the first axis, Altitude, Crown density, Bare rock, and Slope exhibited a positive correlation. In the C. turczaninowii - P. densiflora community (Group III) and C. turczaninowii - Q. mongolica community (Group IV), altitude, bare rock, and slope were analyzed as factors influencing vegetation distribution. In the C. turczaninowii - Q. variabilis community (Group V), C. turczaninowii - P. serrulata Lindl. var. pubescens community (Group VI), and C. turczaninowii - S. japonicus community (Group VII), crown density was analyzed as a factor influencing vegetation distribution.

• The Korean Journal of Ecology
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• v.23 no.5
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• pp.407-421
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• 2000

The forest vegetation surrounding Taegu area was investigated by the methodology of the ZM school of phytosociology, from September, 1994 to August, 1997. The forest vegetation was classified into 7 communities, 8 subcommunities and 5 afforestations as follows : Quercus mongolica community (Typical subcommunity, Carex siderosticta subcommunity), Quercus variabilis community, Quercus acutissima community, Quercus dentate community, Carpinus cordata-Acer mono community (Typical subcommunity, Quercus serrata subcommunity, Cornus controversa subcommunity), Pinus densiflora community (Typical subcommunity, Sanguisorba officinalis subcommunity, Rhododendron schlippenbachii subcommunity), Lespedeza maximowiczii-Rhododendron mucronulatum community , Robinia pseudo-acacia afforestation, Pinus rigida afforestation, Larix leptolepis afforestation, Pinus thunbergii afforestation, Pinus koraiensis afforestation. The differential species of the Quercus mongolica community were Quercus mongolica, Athyrium yokoscense, Rhododendron schlippenbachii, Fraxinus sieboldiana, Acer pseudo-sieboldianum, Symplocos chinensis for. pilosa, Astilbe chinensis var. davidii, Weigela subsessilis, and Melampyrum roseum, those of the Carpinus cordata-Acer mono community were Acer mono, Carpinus cordata, Carpinus laxiflora, and Staphylea bumalda, those of the Pinus densiflora community were Pinus densiflora, Quercus serrata, Cocculus trilobus, and Juniperus rigida. Constance degree of the Quercus serrate was especially high in shrub and herb layers of the Pinus densiflora community. The results of factor analysis by DCA showed that distribution pattern of the communities were similar to that by Z-M method and that communities were arranged according to soil moisture gradient. Rhododendron schlippenbachii subcommunity of the P. densiflora community and the Typical subcommunity of the Q. mongolica community were distributed in similar environments.