• Asian Journal of Business Environment
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• 제11권4호
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• pp.17-29
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• 2021

Purpose: The aim of this study is to explore the dynamic linkage between conditional stock market volatility and macroeconomic uncertainty of Bangladesh. Research design, data, and methodology: This study uses monthly data covering the time period from January 2005 to December 2018. A comprehensive set of macroeconomic variables, namely industrial production index (IP), consumer price index (CPI), broad money supply (M2), 91-day treasury bill rate (TB), treasury bond yield (GB), exchange rate (EX), inflow of foreign remittance (RT) and stock market index of DSEX are used for analysis. Symmetric and asymmetric univariate GARCH family of models and multivariate VAR model, along with block exogeneity and impulse response functions, are implemented on conditional volatility series to discover the possible interactions and causal relations between macroeconomic forces and stock return. Results: The analysis of the study exhibits time-varying volatility and volatility persistence in all the variables of interest. Moreover, the asymmetric effect is found significant in the stock return and most of the growth series of macroeconomic fundamentals. Results from the multivariate VAR model indicate that only short-term interest rate significantly influence the stock market volatility, while conditional stock return volatility is significant in explaining the volatility of industrial production, inflation, and treasury bill rate. Conclusion: The findings suggest an increasing interdependence between the money market and equity market as well as the macroeconomic fundamentals of Bangladesh.

• The Journal of Asian Finance, Economics and Business
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• 제8권1호
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• pp.791-801
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• 2021

This study aims to test whether and to what extend national culture affects the readiness of business-to-consumer (B2C) e-commerce across the world. We regress two sets of data at national level: (1) the ratings of two main dimensions of Hofstede's national culture framework, uncertainty avoidance and individualism, and (2) UTCTAD B2C e-commerce index value. A sample of 83 countries was tested in this study. Several control variables at national level are included in our regression model. We find that these two cultural dimensions have an effect on the readiness of B2C e-commerce in various ways. We find that countries with high individualism score have high index value of B2C e-commerce development. We discuss the implications of these findings for B2C e-commerce developing strategies. We then call for designing relative policies with full consideration on national culture to promote the development of B2C e-commerce. In addition, we identify the limitations of the study and propose recommendations for future research. This study is the first one to use UNCTAD data on B2C e-commerce to explore the relationships between two dimensions of Hofstede's national culture and the readiness of B2C e-commerce and adds to the knowledge of literature in this research field.

• 대한토목학회논문집
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• 제28권6B호
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• pp.723-729
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• 2008

본 연구에서는 홍수지수법의 불확실성을 평가하기 위해 우리나라 강우자료의 지역빈도해석에 적합한 것으로 제안된 generalized logistic 분포형의 quantile에 대한 점근 분산식을 이용하여 성장곡선에 대한 신뢰구간을 산정하였다. 또한 지점 빈도해석과 지역빈도해석에 의한 quantile의 분산을 이용하여 빈도해석의 효율성 지표(efficiency index)를 계산하였다. 우리나라 378개 강우 관측 지점을 바탕으로 구분한 14개 동질 지역에 대해 효율성 지표를 계산한 결과 홍수지수법이 지점빈도 해석보다 불확실성이 더 작은 quantile을 추정하는 것으로 나타났다. 한 지역에 포함되는 지점 개수가 과다하지 않도록 조정하는 것이 지역빈도해석의 효율성 측면에서 나은 것으로 나타났다.

• 한국공간정보시스템학회 논문지
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• 제8권3호
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• pp.117-130
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• 2006

유비쿼터스 센서 네트워크 관련 기술의 급속한 발전으로 센서가 여러 응용 분야에서 널리 활용되고 있다. 일반적으로, 유비쿼터스 센서 네트워크에서 각 센서 노드로부터 센싱되는 데이타는 검색의 효율성을 위해 중앙 서버에 저장된다. 이러한 환경에서 센싱된 데이타의 갱신 비용을 줄이기 위한 갱신지연 등으로 인해 중앙 서버에 불확실한 데이타가 저장되며, 이로 인해 질의 처리 시 잘못된 결과를 야기할 수 있다. 본 논문에서는 유비쿼터스 센서 네트워크에서 불확실한 데이타 처리 방법에 대해서 살펴보고, 불확실한 데이타를 효율적으로 처리하기 위한 인덱스를 제시한다. 이 인덱스는 불확실한 데이타가 실제 존재할 가능성이 있는 영역인 불확실성 영역 내에서 갱신을 지연시킴으로써 갱신 비용을 감소시킨다. 특히, 갱신 지연은 특정 갱신 영역 내에서만 수행되도록 제한함으로써 갱신 지연으로 인해 검색의 정확성이 감소되는 문제를 해결한다. 마지막으로, 성능 평가를 통해 이 인덱스의 성능을 분석하여 우수성을 입증한다.

• 대한조선학회논문집
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• 제56권3호
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• pp.242-250
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• 2019

The speed and power performance of a ship is not only a guarantee issue between the ship owner and the ship-yard, but also is related with the Energy Efficiency Design Index (EEDI) regulation. Recently, International Organization for Standardization (ISO) published the procedure of the measurement and assessment for ship speed and power at sea trial. The results of speed and power performance measured in actual sea condition must inevitably include various uncertainty factors. In this study, the influence for systematic error of shaft power measurement system was examined using the Monte Carlo simulation. It is found that the expanded uncertainty of speed and power performance is approximately ${\pm}1.2%$ at the 95% confidence level(k=2) and most of the uncertainty factor is attributed to shaft torque measurement system.

• 한국기후변화학회지
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• 제7권4호
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• pp.407-419
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• 2016

The low flow is the necessary and important index to establish national water planning, however there are lots of uncertainty in the low flow estimation. Therefore, the objectives of this study are to assess the climate change uncertainty and the effects of hydrological models on low flow estimation. The 5 RCMs (HadGEM3-RA, RegCM4, MM5, WRF, and RSM), 5 statistical post-processing methods and 2 hydrological models were applied for evaluation. The study area were selected as Chungju dam and Soyang river dam basin, and the 30 days minimum flow is used for the low flow evaluation. The results of the uncertainty analysis showed that the hydrological model was the largest source of uncertainty about 41.5% in the low flow projection. The uncertainty of hydrological model is higher than the other steps (RCM, statistical post-processing). Also, VIC model is more sensitive for climate change compared to SWAT model. Therefore, the hydrological model should be thoroughly reviewed for the climate change impact assessment on low flow.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.31-38
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• 2021

The study investigates the diversification behavior of Islamic stocks against US financial uncertainty. Considering limitations found in the literature, a comprehensive index of financial uncertainty (FU) is used, developed by Jurado, Ludvigson, and Ng (2015). The empirical analysis uses monthly data from four Islamic markets - Saudi Arabia, Malaysia, Indonesia, and Turkey - for the period from January 2010 to September 2019. Results of the bivariate EGARCH models show that Islamic stocks can be used for diversification purpose against the financial uncertainty of the US because the volatility of US uncertainty does not propagate in the Islamic stock markets. Moreover, findings show that the spillover effect of financial uncertainty varies with the FU forecast horizon. The spillover effect of FU increases with an increase in the FU forecast horizon and becomes significant over 3-month and 12-month periods in the case of Saudi Arabia. The current volatility of Islamic stock returns is independent of the size of shocks in past volatility. The leverage effect and asymmetry have been found in Saudi Arabia and Malaysia. The findings validate the arguments of the literature that Islamic markets are resilient facing uncertainties and perform well during crisis periods. The findings are important for investors in making better portfolio decisions.

• 한국항행학회논문지
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• 제22권5호
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• pp.375-383
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• 2018

정지한 객체의 측위에 사용되던 Network RTK (real time kinematics) 기술을 이동형 항체의 항법에 적용하기 위해서는 보정정보와 함께 사용자의 성능을 대표할 수 있는 지표가 함께 제공되어야 한다. 이를 위하여 본 논문에서는 I95 (ionospheric index 95) / G95 (geodetic index 95), SBI (semivariance based index), RIU (residual interpolation uncertainty) 등의 지표 도출 알고리즘을 분석하고 이를 국토지리정보원의 기준국 원시 데이터와 VRS (virtual reference station) 사용자에 적용함으로써 정밀 항법 성능 지표로의 활용 가능성을 타진하였다. 24시간 데이터를 처리한 결과 보정정보의 비선형성을 나타낼 수 있는 RIU 지표와 Network RTK 사용자의 위치 정확도와의 상관성이 0.52로 타 지표에 비해 훨씬 높은 것으로 나타났으므로 향후 이동 항체의 항법 성능 지표로 사용이 가능할 것으로 예상된다.

• Current Optics and Photonics
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• 제3권5호
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• pp.415-422
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• 2019

Retroreflection of vehicle headlights, as induced by spherical glass beads, is a key optical phenomenon that provides road-surface markings with greatly enhanced visibility, thus better securing a driver's safety in the nighttime as well as in unclear daytime. Retroreflectance of glass beads is a quite sensitive function of their refractive index, so that measurement of the refractive index of glass specifically in the shape of spherical beads needs to be performed within a reasonable uncertainty that is tolerable for road-marking applications. The Becke line method has been applied in assessing refractive index of such glass beads as e.g. an industrial standard in the Republic of Korea; however, the reference refractive-index liquids are not commercially available these days for refractive index greater than 1.80 due to the toxicity of the constituent materials. As such, high-refractive-index glass beads require an alternate method, and in this regard we propose a practically serviceable technique with uncertainty tantamount to that of the Becke line method: Based on comparison of calculated and measured retroreflectance values of commercial glass beads, we discover that their refractive index can be determined with reasonable precision via the retroreflectance measurement. Specifically, in this study the normalized retroreflectance originating from a single glass sphere is computed as a function of refractive index using the Fresnel equations, which is then validated as coinciding well with retroreflectance values measured from actual specimens, i.e. glass-bead aggregates. The uncertainties involved are delineated in connection with radius and imperfections of the glass beads.

• 경영과정보연구
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• 제38권3호
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• pp.1-19
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• 2019

이 연구에서는 시장의 상황에 따라 이질적으로 나타나는 유가변동성지수(Oil Volatility Index : OVX)가 주식시장에 미치는 효과를 분위수회귀모형을 이용하여 분석하였다. 특히 전체적인 주식시장뿐만 아니라 산업별로 상이하게 나타나는 효과를 분석하기 위하여 2007년 5월부터 2019년 2월까지의 종합주가지수(KOSPI)와 함께 22개 산업별 주가지수 수익률을 사용하였다. 이와 함께 유가변동성지수의 변화율이 증가하는 경우와 감소하는 경우를 구분하여 강세와 약세 시장에서 산업별 주가지수에 미치는 영향을 분석하였다. 그 결과, 각 산업별 주식시장이 약세일 때 유가변동성지수가 미치는 음의 효과가 상대적으로 강하게 나타났으며, 이러한 효과는 강세시장으로 갈수록 사라지는 것을 확인할 수 있었다. 또한 해당 산업의 주식시장이 약세일 때 유가변동성의 증가는 12개 산업에서 통계적으로 유의한 강한 음의 효과를 주는 것으로 나타났으며, 이와는 달리 강세 시장에서는 섬유의복, 기계, 서비스업에서 통계적으로 유의한 양의 효과를 주는 것으로 나타났다. 특히 강세 시장에서 유가변동성 증가가 감소하는 경우 제조업을 포함한 12개 산업에서 주가 수익률에 통계적으로 유의한 음의 효과를 주는 것으로 나타났다. 결과를 통하여 부정적인 소식에 상대적으로 더욱 민감하게 반응하는 주식시장의 특징이 약세시장에서 더욱 명확하게 나타난다는 것을 확인하였다.