• Title/Summary/Keyword: Var Model

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A Study on the Causal Relationship between Logistics Infrastructure and Economic Growth: Empirical Evidence in Korea

  • Wang, Chao;Kim, Yul-Seong;Wang, Chong;Kim, Chi Yeol
    • Journal of Korea Trade
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    • v.25 no.1
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    • pp.18-33
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    • 2021
  • Purpose - This paper investigates the causal relationship between logistics infrastructure development and the economic growth of Korea. Considering the industrial and economic structure of Korea, it is likely that logistics infrastructure is positively associated with the economic growth of the country. Design/methodology - The causal relationship between logistics infrastructure and economic development is estimated using Vector Autoregressive (VAR) and Vector Error Correction Model (VECM) considering long-run equilibrium between the two factors. To this end, a dataset consisting of 7 logistics infrastructure proxies and 5 economic growth indicators covering the period of 1990-2017 is used. Findings - It was found that causality, in general, runs from logistics infrastructure development to economic growth. Specifically, the results indicate that maritime transport is positively associated with the economic growth of Korea in terms of GDP and international trade. In addition, other modes of transport also have a positive impact on either the GDP or international trade of Korea. Originality/value - While existing studies in this area are based on either regional observations or a specific mode of transport, this study presents empirical evidence on causality between logistics infrastructure and the economic growth of Korea using a more comprehensive dataset. In addition, the findings in this paper can provide valuable implications for transport infrastructure development policies.

Anti-Allergic Effect of Fermented Extracts of Medicinal Plants Andrographis paniculate, Salvia plebeia R. Br., Canavalia gladiate, Eleuthorococcus senticosus, Ulmus davidiana var. japonica, and Clerodendrum trichotomum Thunb. ex Murray

  • Mi Jeong, Choi;Yu Ri, Kim
    • Microbiology and Biotechnology Letters
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    • v.50 no.4
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    • pp.512-521
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    • 2022
  • Since the main symptoms of COVID-19 involve the respiratory system, the infection rate of this disease is predicted to be higher in patients with other respiratory conditions such as allergic rhinitis. In such a situation, it will be meaningful to conduct research on an allergy treatment that has fewer side effects and can effectively reduce allergy symptoms. Here, we prepared experimental samples under various fermentation conditions with mixed extracts of six medicinal plants. To examine the anti-allergic efficacy of these samples, an egg albumin-induced allergic rhinitis animal model experiment, a serum histamine and IgE experiment, and a COX and LO inhibitory activity experiment were conducted. As a result of animal experiments, OVA+SP-4 showed superior efficacy compared to OVA+SP-1 in nasal rubbing and sneezing experiments and had anti-allergic efficacy similar to that of OVA-cetirizine. The serum histamine concentration of OVA+SP-4 was also 1.3 times higher than that of the OVA+cetirizine group, showing a high histamine reduction ability, and IgE showed the same trend. An analysis of COX inhibitory efficacy also confirmed that COX-1 and COX-2 inhibitory efficacy is high, and the longer the fermentation time, the higher the antiallergic efficacy. The composition proposed by this study is expected to have a significant effect on sustainable allergy prevention and treatment in the future by applying it to human patients.

The Impact of Energy Crisis and Political Instability on Outsourcing: An Analysis of the Textile Industry of Pakistan

  • ARSLAN, Aniqa;QAYYUM, Arslan;AYUBI, Sharique;KHAN, Sohail Ahmed;ASAD ULLAH, Muhammad
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.3
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    • pp.235-243
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    • 2022
  • To help the industry, outsourcing was found to be the most efficient method. An extensive literature analysis was done to assess the macroeconomic factors associated with outsourcing to supplement the anxious parties' decision-making process with evidence-based comprehensive tools. As a theoretical framework for evaluating these issues, transaction cost economies and resource-based perspective theories are investigated. Outsourcing is proven to be a result of energy crises and political instability. The advantages of outsourcing assist major industries in the economy. To discover the key drivers behind outsourcing, we used the vector autoregressive (VAR model) and step-wise regression techniques for the period 1992 to 2016. This research adds to the literature in that it not only explains the energy issue but also discusses the dilemma of political instability in the country in the context of outsourcing. The findings indicate that labor cost and export tendency have a positive impact on outsourcing strategy, which confirms the study's third and fourth hypotheses. Customs tax, inflation, and the unemployment rate, on the other hand, have a negative impact on textile outsourcing in Pakistan, according to the study's fifth, sixth, and seventh hypotheses.

A Study on the Spillover Effect of Information between Factors Related to Steel Materials and BCI (제철원료 관련 요인과 BCI 간의 정보전이 효과에 관한 연구)

  • Yo-Pyung Hwang;Ye-Eun Oh;Keun-Sik Park
    • Korea Trade Review
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    • v.47 no.2
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    • pp.133-154
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    • 2022
  • The Baltic Capesize Index (BCI), which is used as an indicator for marine transportation of steel raw materials, is one of the key economic indexes for managing the risk of loss due to rapid market fluctuations when steel companies establish business strategies and procuring plans for raw materials. Still, the conditions of supply and demand of steel raw materials has been extremely affected by volatility shocks from drastic events like the financial crisis such as the Lehman Brothers incident and changes in the external environment such as COVID-19. And, especially since the 2008 financial crisis, endeavors to predict the market conditions of the steel raw material is becoming more and more arduous for the deepening uncertainty and increased volatility of BCI, which has been used as a leading indicator of the real economy. This study investigates the correlation between the steel raw material market and the marine transportation market by estimating the spillover effect of information between markets. The vector error correction model (VECM) was used to analyze information transfer based on the correlation between the BCI and crude steel production, capesize fleet supply, raw material price, and cargo volume.

The Connectedness between Categorical Policy Uncertainty Indexes and Volatility Index in Korea, Japan and the US (한국, 일본, 미국의 정책별 불확실성 지수와 변동성지수 간의 연계성)

  • Hangyong Lee; Sea-Gan Oh
    • 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.

Eutrophication of Nakdong River and Statistical Analtsis of Envitonmental Factors (낙동강 부영양화와 수질환경요인의 통계적 분석)

  • Kim, Mi-Suk;Chung, Young-Ryun;Suh, Euy-Hoon;Song, Won-Sup
    • ALGAE
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    • v.17 no.2
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    • pp.105-115
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    • 2002
  • Influences of vrious environmental factors on the eutrophication of Nakdong River were analyzed statistically using water samples collected from 1 January, 1999, to 30 September, 2001 at Namji area. The relationships between the concentration of chlorophyll α (eutrophication index) and environmental factors and were analyzed to develop a statistical model which can predict the status of eutrophication. The concentation of chlorophyll α ranged from 66.2 mg · $m^{-3}$ to 70.8 mg · $m^{-3}$ during dry winter season and the average concentration during this study period was 35.5 mg · $m^{-3}$ Namji area of Nakdong River was in the hypereutrohic stage in terms of water quality. Stephanodiscus sp. and Aulacoseria granulata var. angustissima were dominant species during the witnter to spring time and summer to autumn period, respectively. Based on the correlation analysis and the analysis of variance between chlorophyll α concentration and environmental factors, significantly high positive relationships were found in the order of BOD> pH> COD > KMnO₄ consumption > DO > conductivity > alkalinity. In contrast to these factors, significantly negrative relationships were found as in the order of $PO₄^{3-}-P$ >water level>the rate of Namgang-dam discharge > NH₃-N> the rate of Andong-dam discharge> the rate of Hapchoen-dam discharge. Based on the factors analysis of environmental factors on the concentration of chlorophyll α, we obtained five factors as follows. The first factor included water level, pH, turbiditiy, conductivity, alkalinity and the rate of Namgang-dam discharge. The second factor included water temperature DO, NH₄+-N, NO₃- -N. The third factor included KMnO₄ consumption COD and BOD. The fourth factor included the rate of Andong-dam discharge, the rate of Hapcheon-dam discharge, and the rate of Imha-dam discharge. The final factor included T-N T-P and $PO₄^{3-}-P$ > concentration. We derived two statistica models that can predict the occurrence of eutrophication based on the factors by factor analysis, using regression analysis. The first model is the stepwise regression model whose independent variables are the factors produced by factor analysis : chl α (mg · $m^{-3}$ = 42.923+(18.637 factor 3) + (-17.147 factor 1) + (-12.095 factor 5) + (-4.828 factor 4). The second model is the alternative stepwise regression model whose independent variables are the sums of the standardized main component variables:chl α (mg · $m^{-3}$ = 37.295+(7.326 Zfactor 3) + (-2.704 Zfactor 1)+(-2.341 Zfactor 5).

Predicting Cherry Flowering Date Using a Plant Phonology Model (생물계절모형을 이용한 벚꽃 개화일 예측)

  • Jung J. E.;Kwon E. Y.;Chung U. R.;Yun J. I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.7 no.2
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    • pp.148-155
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    • 2005
  • An accurate prediction of blooming date is crucial for many authorities to schedule and organize successful spring flower festivals in Korea. The Korea Meteorological Administration (KMA) has been using regression models combined with a subjective correction by forecasters to issue blooming date forecasts for major cities. Using mean monthly temperature data for February (observed) and March (predicted), they issue blooming date forecasts in late February to early March each year. The method has been proved accurate enough for the purpose of scheduling spring festivals in the relevant cities, but cannot be used in areas where no official climate and phenology data are available. We suggest a thermal time-based two-step phenological model for predicting the blooming dates of spring flowers, which can be applied to any geographic location regardless of data availability. The model consists of two sequential periods: the rest period described by chilling requirement and the forcing period described by heating requirement. It requires daily maximum and minimum temperature as an input and calculates daily chill units until a pre-determined chilling requirement for rest release. After the projected rest release date, it accumulates daily heat units (growing degree days) until a pre- determined heating requirement for flowering. Model parameters were derived from the observed bud-burst and flowering dates of cherry tree (Prunus serrulata var. spontanea) at KMA Seoul station along with daily temperature data for 1923-1950. The model was applied to the 1955-2004 daily temperature data to estimate the cherry blooming dates and the deviations from the observed dates were compared with those predicted by the KMA method. Our model performed better than the KMA method in predicting the cherry blooming dates during the last 50 years (MAE = 2.31 vs. 1.58, RMSE = 2.96 vs. 2.09), showing a strong feasibility of operational application.

A Study on the Price Fluctuation and Forecasting of Aquacultural Flatfish in Korea (양식 넙치의 가격변동 및 예측에 관한 연구)

  • Ock, Young-Soo;Kim, Sang-Tae;Ko, Bong-Hyun
    • The Journal of Fisheries Business Administration
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    • v.38 no.2
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    • pp.41-62
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    • 2007
  • The Fish aquacultural Industry has been developed rapidly since 1990s in Korea. The total production of fish aquaculture was 5,000ton in the beginning of 1990s, but it was an excess of 80,000ton in 2005. In the beginning of 1990s, the percentage of flatfish yield was 80% of the fish aquaculture in the respect of production. And it has been maintained 50% level in 2005. In this point of view, flatfish aquaculture played the role of leader in the development of fish aquaculture. Rapid increasing of production was not only caused to decreasing in price basically, but also it threatened the management of producer into insecure price for aquacultural flatfish. Therefore, it needs the policy for stabilizing in price, but it is difficult to choose the method because the basic study was not accomplished plentifully. This study analyzed about price structure of aquacultural flatfish. A period of analysis was from January 2000 to December 2005, and a data was used monthly data for price. The principal result of this study is substantially as follows. 1) The price of producing and consuming district is closely connected. 2) A gap between producing district price and consuming district price is decreasing recently, It seems to be correlated with outlook business of aquacultural flatfish. 3) Trend line of the price was declining until 2002, but it turned up after that. The other side, circulated fluctuation was being showed typically. 4) The circle of circulated fluctuation was growing longer, so it seems that the producer was doing a sensible productive activity to cope with changing price. As a result, government's policy needs to be turned into price policy from policy of increased production for aquacultural flatfish. It seems that the best policy is price stabilization polices. And also, government needs to invest in outlook business for aquaculture constantly.

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An Empirical Study on Mutual Influence between Economic Index and Distribution Industry in Korean (한국 유통산업이 한국 경제에 미치는 상호영향력에 관한 실증적 연구)

  • YIM, Byung-Jin
    • 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.

Successional Changes in Seed Banks in Abandoned Rice Fields in Gwangneung, Central Korea

  • Lee, Seon-Mi;Cho, Yong-Chan;Shin, Hyun-Chul;Oh, Woo-Seok;Seol, Eun-Sil;Park, Sung-Ae;Lee, Chang-Seok
    • Journal of Ecology and Environment
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    • v.31 no.4
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    • pp.269-276
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    • 2008
  • In order to understand the role of seed banks for restoration, seed banks in abandoned rice fields in the Gwangneung National Arboretum, central Korea were investigated using the seedling emergence method. The study sites represented three stages: an initial stage dominated by forbs such as Persicaria thunbergii and Juncus effuses var. decipiens, a middle stage dominated by Salix, and a late stage dominated by Quercus aliena and Prunus padus (in nearby riparian forest chosen as a reference stand). DCA ordination arranged the stands according to the number of years since abandonment. CCA ordination identified the dominant environmental variables correlated most closely with Axes 1 and 2 as $Mg^{2+}$ (intraset correlation was 0.827) and $K^+$ (intraset correlation was -0.677), respectively. Species richness and diversity decreased from the initial stage (H'=2.61) to the middle (H'=1.79) and late (H'=0.75) stages. A total of 49 species $(/m^2)$ and 18,620 seedlings $(/m^2)$ emerged out of the seed bank samples. The DCA ordination and similarity analysis detected a large discrepancy between the composition of the actual vegetation and the seed bank. We conclude that the contribution of seed bank to restoration is low. However, seed bank may help the recovery of forbs after disturbance. Some of our results are consistent with the tolerance model of succession whereas others follow the trajectory of the facilitation model. More research on succession will be required to understand the underlying mechanisms.