• 정보처리학회논문지D
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• 제16D권2호
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• pp.169-176
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• 2009

규칙 탐사는 주어진 데이터베이스로부터 빈번하게 발생하는 패턴들을 발견하는 연산이다. 규칙 탐사 연산을 이용하여 주식 데이터베이스로부터 유용한 규칙들을 발견하고 이를 토대로 주식 투자자들에게 주식의 매매를 적절한 시점에 추천할 수 있다. 본 논문에서는 이러한 주식 투자 시스템에서 질의를 효율적으로 처리하기 위한 저장 구조에 관하여 논의한다. 먼저, 주식 투자 추천을 지원하기 위한 다섯 가지 저장 구조들을 제안하고, 각 구조들의 특징과 장단점을 비교한다. 또한, 실제 주가 데이터를 이용한 실험을 통하여 제안된 저장 구조들의 성능을 검증한다. 실험 결과에 의하면, 히스토그램을 이용한 저장 구조의 경우, 기존의 기법에 비하여 질의 처리 성능이 약 170배 개선되는 것으로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.2051-2057
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• 2008

This paper is a feasibility study on the calculation of operating cost in regards to the overall operation following the completion of a number of LRT lines currently in progress. Owing to the absence of operating experience in driveless LRT system at home, the difficulties lie in the assumption of the optimal operating budget applying domestic real situation. Nevertheless, with 34 years of accumulated operating experience in heavy rail transit system, Seoul Metro, the nation's biggest urban rail transit operator, performs O&M consultancy services for several on-going projects along with every effort to acquire know-how where the appropriateness of the cost estimation as a required deliverable is reviewed and a more efficient way is provided. The main focus of this study is to seek a method to calculate the optimal amount of operating expenses as well as a cost-effective alternative for possible weaknesses from the standpoint of the operator. The body of this paper discusses the five issues such as personnel cost, overhead, maintenance cost, additional purchase price, alternative investment fee from a more macroscopic point of view, and the conclusion deals with the adequacy of the reason for selection of institutions with various operating know-how.

• The Journal of Asian Finance, Economics and Business
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• 제8권12호
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• pp.63-73
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• 2021

This study investigates the key determinants of exchange rate (RER) misalignment for the period 1991 to 2020. The BEER technique has been used to estimate the degree of the equilibrium exchange rate. To explore the actual exchange rate misalignment and to assess the behavior of variables that are different in different regimes of undervaluation and overvaluation, the nonlinear technique of Markov regime-switching (MSM) was applied. The mean and variance of each regime are highly significant and show that undervaluation episodes have a low mean (116.139) and more volatility (1.229) while overvaluation episodes have a high mean (126.732) with less volatility (0.871). The findings show that MSM accurately identifies exchange rate misalignment in both regimes as separate incidents of overvaluation and undervaluation. Results further depict that misalignment of the RER is affected by terms of trade, net foreign assets, interest differential, government investment, and consumption decision. Results recommend that if policymakers want to use the exchange rate as a policy tool, they must first consider the drivers of the equilibrium exchange rate. As a result, any deliberate actions to address exchange rate misalignment must focus on the underlying fundamentals that drive the exchange rate.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.777-784
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• 2021

This study explores the impact of COVID-19 pandemic and the lockdown policies that are used to tackle the pandemic on stock market returns in Indonesia. This study uses fixed-effects panel-data regression method to evaluate the impact of the growth in COVID-19 total confirmed cases and death as well as the lockdown policies on daily stock returns of 272 firms that are listed on the Indonesia Stock Exchange's main board and operate in the real sector from 2 March 2020 to 27 November 2020. The study confirms the significantly adverse impact of growth in the total of confirmed cases and death due to COVID-19 on Indonesia's daily stock returns. Moreover, the lockdown policies regardless how strict they are, have a positive and significant impact on the Indonesia's daily stock returns. This study further considers the different impact of COVID-19 pandemic on each of eight observed sectors; where the sector of property as well as trade, service and investment have a significantly negative performance; while the sector of basic industry, consumer goods and mining have a significantly better performance. This study suggests that COVID-19 pandemic and the lockdown policies have a mixed impact on the Indonesia's stock market returns.

• 건축역사연구
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• 제28권4호
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• pp.37-46
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• 2019

Busanjin Fortress was originally made of stone fortress for the Joseon Navy, which was located in Dongnae area in the late Joseon Dynasty. However, the Japanesque Castle of Busanjin in 1592 was built by the Japanese military during the Japanese Invasion of Korea. Since the Japanese military retreated, the Joseon Navy had renovated the fortress and had used it as a base for stationing, and it had been maintained in Busanjin Fortress until the Joseon Navy was disbanded in 1895. After the abolition of the Naval Force System, the space in Busanjin Fortress was dismantled, and the government facilities and their sites were not properly managed and repaired, eventually was sold to Japanese. As Busanjin Fortress failed to function properly, the coastal space in Busanjin became a burial ground after being reclaimed by Japanese with real estate investment in mind. Today, the traces of Busanjin Fortress have been removed by the reclamation work, and only the remains of some stone pillars remain under the name of Jaseongdae(子城臺). Thus, the old custom as the Naval base disappeared, leaving only the image of Japanesque Castle.

• 유통과학연구
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• 제20권12호
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• pp.109-116
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• 2022

Purpose: The purpose of this study is to analyze the rental determinants of a small shopping mall located in Seoul, Korea, and the characteristics of four commercial districts (CBD, GBD, YSD, etc.). Research design, data, and methodology: For the characteristics of the data, descriptive statistics and frequency analysis were used. Artificial Neural Networks (ANNs) have been used as rental determinants for small shopping malls. The characteristics of 4 commercial districts were analyzed using Analysis of variance (ANOVA) and post-hoc analysis. Results: 1) CBD 14.8%, GBD 16.7%, YSD 13.0%, others 55.6%. 2) The order of important variables affecting rent: CBD=1> GBD=1> vacancy rate> rental index> number of buildings> YBD=1> average gross floor area> conversion rate> average floor. 3) Characteristics of commercial district: Rents in CBD and GBD are high. The conversion rate is high in the GBD commercial area. The number of buildings is high in the CBD. The average area of GBD is larger than that of other commercial districts. Conclusions: 1) Several factors should be considered when investing in or renting a small shopping mall. 2) Depending on the investment and business purpose, factors such as rent, conversion rate, building, and area average should be considered.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.55-67
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• 2021

This study aims to measure the lower tail dependence as risk contagion from the U.S. economy to 18 developing countries affecting FDI inflows using time-series data from 2005 to 2019. Firstly, we utilize four dynamic copula models, namely, Student-t, Clayton, rotated survival Gumbel, and rotated survival Joe, to measure the tail dependence structure between the U.S. and each developing country's real GDP growth. Secondly, we use the regression model to explore the contagion effects on FDI inflows. The results show that there is evidence of the tail dependence between the U.S and developing economies, indicating the presence of the contagion effects. Primarily, we observe that the degree of contagion effects of the global financial crisis varies across countries; a strong impact is observed in Chinese, South African, Russian, Colombian, and Mexican economic growth. Furthermore, we found significant contagion risk affecting FDI inflows positively in China, Indonesia, Columbia, Morocco, and negatively in the Philippines, Bulgaria, and South Africa. This study demonstrates the usefulness of the copulas model in terms of examining contagion. Our findings shed light on the influence of sound policies and regulations to cope with both positive and negative consequences of the contagion on the capital movement.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.39-47
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• 2021

This research aims to confirm if the COVID-19 pandemic has had an impact on existing sectors, and how that affects the Indonesian Stock Exchange (IDX) market returns. The research method used is an event study employing market models in nine sectors of the Exchange with purposive sampling technique, and supported by Ordinary Least Square (OLS) regression. Based on the calculation of abnormal returns in the period of 30 days before up to 30 days after, the financial property, real estate, and construction sector results show a decreased abnormal return value. The infrastructure, utilities, and transportation sectors also show an abnormal return value that tends to be constant, while the abnormal return value increases in other sectors. Judging from the cumulative value of abnormal returns, the most affected sector is financials, followed by the trade, service, and investment sectors. The consumer goods and mining industry sectors are still optimistic, while other sectors show temporary negative sentiment. Overall, the stocks on the Indonesia Stock Exchange (IDX) were affected by the COVID-19 pandemic with a cumulative negative value of the average abnormal return sample. The results using OLS regression also strengthen the relationships between the COVID-19 pandemic, and negative and significant market returns.

• 유통과학연구
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• 제19권3호
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• pp.25-34
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• 2021

Purpose: The purpose of this study is to analyze the economic ripple effect(ERE) of logistics industry by construction of Trans-Korea Railway (TKR) and present policy measures to minimize the economic loss of South Korea (SK). Research design, data and methodology: As the analysis method, exponential smoothing was used for demand forecasting, Input-Output analysis was used to estimate the economic ripple effect coefficient, and scenario analysis was used to an efficient way to invest in TKR to minimize SK's economic losses. Results: 1) the production(logistics fares) of TKR for 10 years after its completion is about 11.42 trillion won in positive relations, and 26.89 billion won in negative relations. 2) the ERE of SK in positive relations is 24.32 trillion won in production inducement effect, 8.1 trillion won in value-added inducement effect, 3.54 trillion won in import inducement effect, and 70,930 persons in employment inducement effect. But the ERE was insufficient in the negative relations. 3) SK's efficient investment method is providing materials and equipment by SK and building the TKR by North Korea in positive inter-Korea relations. Conclusions: For the successful operation of TKR, international cooperation, legalization and stable peace settlement on the Korean Peninsula are required.

• Communications for Statistical Applications and Methods
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• 제28권1호
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• pp.59-79
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• 2021

Value at Risk (VaR) is one of the most common risk management tools in finance. Since a portfolio of several assets, rather than one asset portfolio, is advantageous in the risk diversification for investment, VaR for a portfolio of two or more assets is often used. In such cases, multivariate distributions of asset returns are considered to calculate VaR of the corresponding portfolio. Copulas are one way of generating a multivariate distribution by identifying the dependence structure of asset returns while allowing many different marginal distributions. However, they are used mainly for bivariate distributions and are not widely used in modeling joint distributions for many variables in finance. In this study, we would like to examine the performance of various copulas for high dimensional data and several different dependence structures. This paper compares copulas such as elliptical, vine, and hierarchical copulas in computing the VaR of portfolios to find appropriate copula functions in various dependence structures among asset return distributions. In the simulation studies under various dependence structures and real data analysis, the hierarchical Clayton copula shows the best performance in the VaR calculation using four assets. For marginal distributions of single asset returns, normal inverse Gaussian distribution was used to model asset return distributions, which are generally high-peaked and heavy-tailed.