• Journal of Biomedical Engineering Research
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• v.35 no.4
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• pp.95-98
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• 2014

The baroreflex is one kind of homeostatic mechanisms to regulate acute blood pressure (BP) changes by controlling heartbeat interval (HBI). To quantify the effect of baroreflex, we suggested a new approach of analyzing Granger causality between systolic BP (SBP) and HBI. The index defined as baroreflex effectiveness (BRE) was generated by the hypothesis that more effectual baroreflex would be related to more effective Granger causal influence of SBP on HBI. Six obstructive sleep apnea (OSA) patients (apnea-hypopnea index, AHI ${\geq}5$ events/hr) and six normal subjects participated in the study. Their SBP and HBI during nocturnal sleep were obtained from a non-invasive continuous BP measurement device. While the BRE ($mean{\pm}SD$) of normal subjects was $47.0{\pm}4.0%$, OSA patients exhibited the BRE of $34.0{\pm}3.8%$. The impaired baroreflex function of OSA patients can be explained by the physiological mechanism associated with recurrent hypoxic episodes during sleep. Thus, the significantly lower BRE in OSA patients verified the availability of Granger causality analysis to evaluate baroreflex during sleep. Furthermore, the range of BRE obtained from normal subjects was not overlapped with that obtained from OSA patients. It suggests the potential of BRE as a new helpful tool for diagnosing OSA.

• International Area Studies Review
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• v.12 no.3
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• pp.449-465
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• 2008

This paper aims to analyze the causal relationship between exports and regional economic growth based on the provincial data over the period from 1952 to 2004. To reflect the regional and chronical characteristics, this paper divides China into three regions; Eastern, Central and Western regions, and also the whole period into two sub-periods; before and after 1979 when the Open-door policy(ODP) was initiated and applies Granger causality analysis. The Granger causality tests showed that exports Granger cause economic growth in the Eastern region, but not in the Central and Western regions, as a whole. When the period is divided, in the Eastern region, causal relation between the two variables was not found before the Open-door policy. For the second period, however it turns out that exports cause the region's economic growth. This result is consent with the fact that the region has been a main beneficiary of the policy. For the Central region, the tests showed no causality in the pre-ODP period, but significant bidirectional causality in the post-ODP period. Meanwhile, in the Western region, exports turned out causing economic growth significantly before the ODP, while economic growth appeared to causing trade after the ODP.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.281-286
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• 2023

This study analyzed the causal relationship between housing sales prices and jeonse prices in Seoul, specifically in the Gangnam and Gangbuk neighborhoods. The time-invariant Granger causality test showed bidirectional causality between the sales price and the jeonse price in Seoul and Gangbuk, but no bidirectional causality was found in Gangnam. However, the time-varying Granger causality test showed a Granger causal relationship between the housing jeonse price and the sales price for the entire period after 1993 in all three areas. Notably, the causal effect of jeonse prices on sales prices has been continuous in Gangnam since 2010. These analysis results suggest that an increase in liquidity supply to the jeonse market could increase volatility throughout the housing market, given the strong influence between the sales and jeonse markets in both directions.

• International Commerce and Information Review
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• v.8 no.2
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• pp.299-312
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• 2006

This study examines the relations among wage differentials, trade, and productivity in Korea, using the methodology of Granger causality and vector error correction modelling. Cointegration test results over the 1975-2004 period indicate that all the test variables are cointegrated. Therefore, wage differentials, trade, and productivity are all related in the long run. We found some evidence on long-run relationship, while there is no short-run relationship between three test variables. First, trade and wage differentials have positively and bi-directionally Granger causality in the long-run. Second, productivity Granger causes negatively wage differentials in the long-run. Finally, productivity Granger causes positively trade in the long-run. These results explain partially the current theoretical predictions for wage inequality as well as supports the productivity-led growth hypothesis in the Korean economy.

• Journal of Climate Change Research
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• v.9 no.2
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• pp.171-179
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• 2018

The causal relationship between El Nino-Southern Oscillation (ENSO) and winter climate variability in Korea is tested by analyzing Korea Meteorological Administration Automatic Synoptic Observing System datasets for the past 59 years. Consistent with previous studies, positive phase of ENSO (El Nino) tends to cause warmer temperature and heavier precipitation in Korea in early winter with three-week lead time. This causality is quantified by performing Granger causality test. It turns out that ENSO explains an additional 9.25% of the variance of early-winter temperature anomalies in Korea, beyond that already provided by temperature itself. Likewise, 22.18% additional information is gained to explain early-winter precipitation variance by considering ENSO. This result, which differs from simple lead-lag correlation analysis, suggests that ENSO needs to be considered in predicting early-winter surface climate variability in Korea.

• Journal of Technology Innovation
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• v.11 no.2
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• pp.175-193
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• 2003

The purpose of this study is to examine relationship between public R&D investment and private R&D investment in Korea, and to obtain policy implications of the results. To this end, the author attempts to provide more careful consideration of the causality issues by applying rigorous techniques of Granger causality. Tests for unit roots, co-integration, and Granger causality based on an error-correction model are presented. The existence of bi-directional causality between public R&D investment and private R&D investment is detected. This finding has various implications for policy analysts and forecasters. Increasing private R&D investment requires enormous public R&D investment, though there are many other factors contributing to private R&D investment, and public R&D investment is but one part of it. Thus, this study generates confidence in decisions to invest in public R&D. Moreover, this study lends support to the argument that increase in private R&D investment, ceteris paribus, gives rise to public R&D investment. Increase in private R&D investment results in greater national income to be spent on R&D investment and stimulates further public R&D investment.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2001.05a
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• pp.141-158
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• 2001

This paper examines the causality issue between telecommunications investment and economic growth for South Korea by applying recently developed time series techniques. Tests for unit roots, co-integration, and Granger causality are presented. The results show that hi-directional causality runs from telecommunications investment to economic growth for South Korea. This means that increased telecommunications investment directly affects economic growth and an increase in real income also influences telecommunications investment. The study also discusses the implications of the results for addressing telecommunications policy in South Korea.

• Information Systems Review
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• v.19 no.1
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• pp.185-202
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• 2017

Most studies based on production function theory have concluded that economic growth is a result of information technology (IT) capital use. However, some studies have indicated that economic growth is a determinant of IT investment. To determine if these results also hold at the industry level, we use the Granger causality test to analyze bidirectional causality with industry-level data for 1977~2007 from the United States. The results generally reveal that IT investment causes economic growth in many industries under the concept of Granger causality, that economic growth causes IT investment in some industries, and that IT investment is not associated with economic growth in some industries. In the country-level time-series data made by summing up the IT capital and gross output for each industry, the results do not show any causality between IT investment and economic growth. However, they show bi-directional causality between IT investment and economic growth in the panel data. These results may be a source of IT productivity paradox.

• Environmental and Resource Economics Review
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• v.21 no.3
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• pp.573-593
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• 2012

The paper examined the relationship between total and sector level electricity consumptions and economic growth in Korea for the period of 1980-2009. The results of unit-roots and cointegration tests show that all variables-real GDP, total, primary, manufacture, and service sector electricity consumptions-were not stationary and there were no linear combinations in the long run between electricity consumptions and economic growth. Thus, by using standard Granger-causality test we found that total, primary, and manufacture sector electricity consumptions were Granger-caused by economic growth, not vice versa. This means that causality runs from economic growth to each electricity consumption. However, there is no causal relationship between service sector electricity consumption and economic growth. These results imply that the government policies aimed at reducing electricity consumptions and increasing energy efficiency etc. can be feasible without deterring economic growth in Korea.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.469-474
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• 2019

One of the world's major resources is crude oil, the most fundamental part of the industry. There is no place that does not use crude oil. Petroleum refining products and chemical production industrial products are produced through nearby petrochemical complexes and ports after importing crude oil. There would be a possible relationship among the petrochemical complexes and nearby regional ports working with liquid cargoes. To confirm these relations, Ulsan Port, Daesan Port, and Yeosu Gwangyang Port were selected for this study. A Vector Auto Regressive model using time series data was applied. A Unit Root Test was performed. The relationship was confirmed through the Granger and Toda Yamamoto Causality Test.