• Ocean and Polar Research
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• v.41 no.3
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• pp.121-133
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• 2019

Natural variability associated with a variety of large-scale climate modes causes regional differences in sea level rise (SLR), which is particularly remarkable in the Pacific Ocean. Because the superposition of the natural variability and the background anthropogenic trend in sea level can potentially threaten to inundate low-lying and heavily populated coastal regions, it is important to quantify sea level variability associated with internal climate variability and understand their interaction when projecting future SLR impacts. This study seeks to identify the dominant modes of sea level variability in the tropical Pacific and quantify how these modes contribute to regional sea level changes, particularly on the two strong El $Ni{\tilde{n}}o$ events that occurred in the winter of 1997/1998 and 2015/2016. To do so, an adaptive data analysis approach, Ensemble Empirical Mode Decomposition (EEMD), was undertaken with regard to two datasets of altimetry-based and in situ-based steric sea levels. Using this EEMD analysis, we identified distinct internal modes associated with El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) varying from 1.5 to 7 years and low-frequency variability with a period of ~12 years that were clearly distinct from the secular trend. The ENSO-scale frequencies strongly impact on an east-west dipole of sea levels across the tropical Pacific, while the low-frequency (i.e., decadal) mode is predominant in the North Pacific with a horseshoe shape connecting tropical and extratropical sea levels. Of particular interest is that the low-frequency mode resulted in different responses in regional SLR to ENSO events. The low-frequency mode contributed to a sharp increase (decrease) of sea level in the eastern (western) tropical Pacific in the 2015/2016 El $Ni{\tilde{n}}o$ but made a negative contribution to the sea level signals in the 1997/1998 El $Ni{\tilde{n}}o$. This indicates that the SLR signals of the ENSO can be amplified or depressed at times of transition in the low-frequency mode in the tropical Pacific.

• East Asian Economic Review
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• v.18 no.1
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• pp.55-81
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• 2014

This study aims to answer two questions using input-output decomposition analysis: 1) Have emerging Asian economies decoupled? 2) What are the sources of structural changes in gross outputs and value-added of emerging Asian economies related to the first question? The main findings of the study are as follows: First, since 1990, there has been a trend of increasing dependence on exports to extra-regions such as G3 and the ROW, indicating no sign of "decoupling", but rather an increasing integration of emerging Asian countries into global trade. Second, there is a contrasting feature in the sources of structural changes between non-China emerging Asia and China. Dependence of non-China emerging Asia on intra-regional trade has increased in line with strengthening economic integration in East Asia, whereas China has disintegrated from the region. Therefore, it can be said that China has contributed to no sign of decoupling of emerging Asia as a whole.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.182-186
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• 1997

This paper presents a mathematical approach to implementing distributed optimal power flow (OPF), wherein a regional decomposition technique is adopted to parallelize the OPF. Three mathematical decomposition coordination methods are introduced firs to implement the proposed distributed scheme: the Auxiliary Problem Principle (APP), the Predictor-Corrector Proximal Multiplier Method (PCPM), and the Alternating Direction Method (ADM). Then two alternative schemes for modeling distributed OPF are introduced; the Dummy Generator-Dummy Generator (DGDG) scheme and Dummy Generator-Dummy Load (DGDL) scheme. We present the mathematical analyses of the proposed approach, and demonstrate the approach on several test, systems, including IEEE Reliability Test Systems and parts of the ERCOT (Electric Reliability Council of Texas) system.

• East Asian Economic Review
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• v.28 no.1
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• pp.37-67
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• 2024

This paper analyses carbon emissions and value-added embodied in trade between two large developed countries, South Korea and the United States, during 2000-2014. Using multi-regional input-output (MRIO) tables, our analysis reveals that carbon emissions and value-added embodied in exports grew by 19% and 101% for South Korea but shrank by 43% and 7% for the United States. As a result, South Korea experienced a 40% increase in net carbon exports and 243% increase in net value-added exports. At the industry level, the primary drivers of changes in carbon exports were electricity and basic materials. The majority of industries in witnessed improvements in carbon intensities suggesting improved environmental efficiency. While both countries achieved a decoupling of carbon emissions from value-added exports, substantial year-to-year and sectoral variations were observed. Finally, structural decomposition analysis indicates that domestic supply-side factors played a role in decreasing emissions whereas foreign demand-side factors contributed to emissions increases. In line with the main findings, various implications for policy and future research are discussed.

• Korea journal of population studies
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• v.26 no.1
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• pp.171-194
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• 2003

The present study investigates the effects of lopsided regional policy and social prejudice on homeownership disparities by household's place of birth of household head in Seoul. The present study utilizes individual household-level census data (2% sample) to evaluate households' residential well-being denoted by homeownership status during the period of 1980-2000. Decomposition techniques based on tenure choice models were used to provide evidences of the home-ownership disparities caused by regional policy and prejudice. We found that households from Gangwon and Honam provinces represent a disproportionately small percentage of homeownership compared with those originated from other provinces. In the statistical analysis, the present study found that having controlled for the factors traditionally thought to influence households' choice of housing tenure, as well as other housing market characteristics in Seoul, place of birth has played a primary role in determining whether or not households become a homeowner. Most strikingly, while most of the disparity in homeownership ratios between households from Youngnam and households from Gangwon in the housing market is due to the endowment differences in human capitals they bring to the market, those between households from Youngnam and households from Honam is largely due to residual differences explained mainly by social discrimination and prejudice against people from Honam. The present study summarized that place of birth has played a primary role in determining whether or not households become a homeowner in Korea. The present study concluded with some policy issues relevant to this study and suggested some future studies.

• Journal of the Korean association of regional geographers
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• v.11 no.1
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• pp.83-100
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• 2005

The Seoul Metropolitan Area's economy has undergone structural changes since the 1990s. With recent structural changes in the Korean economy in mind, this paper employs a decomposition analysis of Gross Regional Domestic Product per head and labor productivity to examine how the region's economic performance has changed relative to that of Korea since the 1900s. There are some findings. First, a strong cumulative causation process, derived from industrial linkages and agglomeration effects, has oocurred in the Seoul Metropolitan Area, widening economic disparities between the Seoul Metropolitan Area and the other regions especially since the Korean financial crisis in 1997 mainly due to Gyeonggi province's overwhelming cumulative GRDP growth relative to the national average. Second, the Seoul Metropolitan Area has begun w display good economic performance in terms of labour productivity relative w the national average since the late 1990s, with the region's industrial upgrading being implemented. Finally, manufacturing, financial intermediation and communications have made sensitive contributions to relative Seoul Metropolitan Area's labor productivity growth.

• Journal of the Korean Regional Science Association
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• v.39 no.4
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• pp.53-71
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• 2023

This study aims to identify the contribution of factors to employment growth over the past 20 years (1996-2016) for seven metropolitan areas in Korea. For this purpose, we performed a multifactor partitioning (MFP) analysis based on the business survey data provided by Statistics Korea. The key findings of the analysis are as follows. First, over the long run, the region effect is dominant in metropolitan employment growth, followed by the industry mix effect. On the other hand, the dynamic MFP findings suggests that future regional employment disparities are likely to be explained by industry structure. Second, the gender mix and decent job mix effect do not significantly contribute to regional employment growth. However, the contributions of individual factors are not invalid, and it is possible to infer a pattern of declining employment for men-permanent workers and increasing employment for women-contingent workers. These results indicate the importance and necessity of employment policies that can promote structural transition in regional industries and qualitative growth accompanied by employment stability.

• Atmosphere
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• v.18 no.2
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• pp.83-95
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• 2008

In this study we have investigated the preceding eighteen large-scale climate indices with a lead time from zero to twelve months that have an influence on the variability of temperature and precipitation in Korea in order to understand which climate indices are overall available as predictors for long-range forecasting. We also have studied the dynamic link between preceding large-scale climate indices and regional climate using singular value decomposition analysis (SVDA) and correlation analysis (CA). Based on the coupled mode between large-scale circulation and regional climate, and correlation pattern between the preceding large-scale climate indices and large-scale circulation, the level of significance on climate indices as a predictor for monthly mean temperature and precipitation was evaluated for 5 and 1% level.

• East Asian Economic Review
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• v.19 no.4
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• pp.357-379
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• 2015

We investigate interconnectedness and the contagion effect of default risk in Asian sovereign CDS markets since the global financial crisis. Using dynamic conditional correlation analysis, we find that there are significant co-movements in Asian sovereign CDS markets; that such co-movements tend to be larger between developing countries than between developed and developing countries; and that in the co-movements intra-regional nature is stronger than inter-regional nature. With the Spillover Index model, we measure contagion probabilities of sovereign default risk in CDS markets of seven Asian countries and find evidence of contagion effects among six of them; Japan is the exception. In addition, we find that these six countries are affected more by cross-market spillovers than by their own-market spillovers. Furthermore, a rolling-sample analysis reveals that contagion in the Asian sovereign CDS markets expands during episodes of extreme economic and financial distress, such as the Lehman Brothers bankruptcy, the European financial crisis, and the US-credit downgrade.

• Journal of Electrical Engineering and Technology
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• v.2 no.3
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• pp.335-341
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• 2007

In this study, we present an approach to parallelizing OPF that is suitable for distributed implementation and is applicable to very large inter-connected power systems. The approach could be used by utilities for optimal economy interchange without disclosing details of their operating costs to competitors. It could also be used to solve several other computational tasks, such as state estimation and power flow, in a distributed manner. The proposed algorithm was demonstrated with several case study systems.