• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.499-513
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• 2009

An economic signal in the real world usually reflects complex phenomena. One may have difficulty both extracting and interpreting information embedded in such a signal. A natural way to reduce complexity is to decompose the original signal into several simple components, and then analyze each component. Spectral analysis (Priestley, 1981) provides a tool to analyze such signals under the assumption that the time series is stationary. However when the signal is subject to non-stationary and nonlinear characteristics such as amplitude and frequency modulation along time scale, spectral analysis is not suitable. Huang et al. (1998b, 1999) proposed a data-adaptive decomposition method called empirical mode decomposition and then applied Hilbert spectral analysis to decomposed signals called intrinsic mode function. Huang et al. (1998b, 1999) named this two step procedure the Hilbert-Huang transform(HHT). Because of its robustness in the presence of nonlinearity and non-stationarity, HHT has been used in various fields. In this paper, we discuss the applications of the HHT and demonstrate its promising potential for non-stationary financial time series data provided through a Korean stock price index.

• Journal of the Korean Society of School Health
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• v.22 no.2
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• pp.25-36
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• 2009

Purpose: The purpose of this study was to estimate income-related health inequalities among adolescent population across regions in Korea. Methods: Data of 8,456 adolescents from 1998, 2001, 2005, 2007 Korean Health and Nutrition Examination Survey were used for the analysis. True health status was proxied by self-rated health and overweight status. Per capita income was computed from household monthly average income adjusted by consumer price with base year 2005. Adolescent health inequalities were estimated by Concentration Index (CI) across income and space. Results: Ill health score was related with age (p<0.0001), gender (p=0.0155) and income (p<0.0001). Negative relationship between income and ill-health indicated that higher income group tended to enjoy better health and less overweight. These evidences suggested ill health were accumulated on the economically disadvantaged adolescents. The size of health inequalities (ill-health score) were estimated as CI=-0.057 and CI=-0.030 across income groups and regions, respectively. Comparable measures of within region health disparities were also observed. Conclusion: Since health disparity among adolescent population was small compared to adult population, lessening adolescent health inequality could be a helpful way of mitigating health disparities in later stage. Considering life stage of adolescents, school system and local communities could play important roles toward adolescent health distribution. Although health disparity between regions existed, health disparity within a region should not be neglected.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.55-62
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• 2002

With lower quality and three to four times higher price than those of imported malting barley, the competitiveness of domestic malting barley is decreasing. Although the causes can be found in that the domestic environments are much unfavorable to cultivate the malting barley compared with those of USA or Canada, it is mainly reasoned from poorer developments in variety of high quality malting barley as well as in cultivation technology. For assuring the competitiveness of domestic malting barley, therefore, not only the development of high quality malting barley suitable to the climatic environment of this country but also the political supports of the government are required. Also, in addition to the breeding of the good quality malting barley haying higher germinative energy, and heavier and larger kernels of good plumpness as well as lower protein content, the modification of quality inspection standards from the system relying only on the visual characteristics such as kernel size distribution rate, shrimped kernel rate, foreign materials and so on, to such system as those of developed countries haying quality criteria such as protein content for inspection is absolutely required for the quality improvement of domestic malting barley.

• Journal of the Korean Dietetic Association
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• v.15 no.3
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• pp.262-277
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• 2009

Fresh-cut foods have been widely used in the school foodservice industry due to their convenience and saving effects of labor and working hours. This study evaluated the effectiveness of using fresh-cut foods in school foodservice with respect to cost efficiency, customer satisfaction, employee satisfaction, and productivity. First, in terms of cost efficiency, the cost of the fresh-cut food per meal price significantly increased by 2.6% via the new production plan. Meanwhile, the costs of labor and food wastes significantly decreased by 3.0% and 0.3%, respectively, after implementing the new plan. Second, customer satisfaction towards foodservice significantly increased, from 2.94 points prior to the new plan to 3.45 points. Third, foodservice productivity such as of the number of meals per full-time equivalent employee increased by 5.7 meals, from 143.0 meals to 148.7 meals after intervention. The productivity index of work hours for producing a meal also increased and was reflected by a work time reduction of 0.77 minutes, specifically from 4.25 minutes to 3.48 minutes. The labor cost per meal also decreased by 29.9 won, from 331.91 won to 301.97 won, but there was no significant difference. Through these results, we identified that using pre-process foods in school foodservice has positive effects on labor saving, customer satisfaction, and employee work satisfaction.

• Korean Journal of Human Ecology
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• v.10 no.4
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• pp.357-363
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• 2001

The purpose of this study was to provide buying condition of women focusing on age groups and satisfaction with ready-to-wear and basic data in designing ready-to-wear for women. The questionnaire method was used and one-to-one interviews were held for residents in Iksan, Jonju areas. Total 252 subjects were surveyed and used for statistical analysis and were analyzed by Frequency, ANOVA, CROSSTABS, $x^2-test$. Women for this study were classified 3 groups(young women, middle aged women, obesity women). The results of this study were as follows; 1) Both BMI and Rohrer index are significantly different according to 3 groups. 2) In the buying method, more than 97% of the middle aged women and obesity women had purchased ready-to-wear apparel. 3) While young women purchased their clothing in the Bose store, middle aged women and obesity women purchased their clothing in the department store. 4) In young women and middle aged women group, the most important criteria of buying were design. In obesity women, the most important criteria of buying were design, size (fitness), price. 5) For the satisfaction of ready-to-wear with aging, 34.1% of all respondents showed dissatisfaction. There was significant difference according to the age. 6) In the fit of ready-to wear, When ready-to-wear is not fit, more than 40% was purchased big or small.

• Journal of Family Resource Management and Policy Review
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• v.11 no.2
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• pp.133-154
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• 2007

This research investigated consumer's usage of, evaluation on and satisfaction of the Auction Site, with a view to analyze the key factors influencing a commission paid Auction Site. The findings of results from the analysis are summarized as follows. First of all, the consumer group at the age equal to and less than 20 years old showed the highest purchasing frequency, and the consumer group with a household income less than 2,500,000 won showed the highest number of hours on the site. Secondly, the evaluation index showed that consumers think highly of the complaint resolution process, and, especially, the aged consumer group respected the Auction Site's level of confidentiality of transaction and privacy. Thirdly, among consumers' satisfaction, subdivided by types, price satisfaction was the highest followed by quality satisfaction, settlement satisfaction, delivery satisfaction, information satisfaction and AS satisfaction, in that order. Fourthly, in the event consumers used the commission paid Auction Site, the number of times it has been used, evaluations related to information provision and evaluations on confidentiality of transactions and privacy are influential parameters.

• Environmental and Resource Economics Review
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• v.10 no.2
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• pp.135-159
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• 2001

This study analyses the energy consumption increase by using a physical production index (PPI) based decomposition method. The energy efficiency of the Korean industry deteriorated to a large extent in the 1992 to 1997 period. This outcome, however, does not contradict the result of a previous study that the physical energy intensities (measured by energy use per production unit) decreased in four Korean energy intensive industries such as steel, cement, petrochemical and pulp and paper in the same period. Although the physical energy intensities in four industries considered decreased significantly, the energy efficiency of the Korean industry deteriorated because the increase in the value-added production was smaller than that in the physical production except for the steel industry. This outcome suggests that the reduction in the physical energy intensity alone will not result in reducing the economic energy intensity, thereby reducing the increase in the energy consumption of the Korean industry. Therefore, it necessitates to restructure the Korean industry towards a higher value-added production and to strengthen energy efficiency improvement efforts in the Korean industry. As the overinvestment in the energy intensive industries caused a deep price fall of Korean products and a reduction of the value added of the Korean industry and with it an increase in the economic energy intensity, a decrease in this intensity will highly depend on reducing the overcapacity in the energy intensive industries which was partly responsible for the currency and economic crisis of 1997.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.83-93
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• 2020

This empirical research aims to modeling and improving the forecasting accuracy of the volatility pattern by employing the Saudi Arabia stock market (Tadawul)by studying daily closed price index data from October 2011 to December 2019 with a number of observations being 2048. In order to achieve significant results, this study employs many mathematical functions which are non-linear spectral model Maximum overlapping Discrete Wavelet Transform (MODWT) based on the best localized function (Bl14), autoregressive integrated moving average (ARIMA) model and generalized autoregressive conditional heteroskedasticity (GARCH) models. Therefore, the major findings of this study show that all the previous events during the mentioned period of time will be explained and a new forecasting model will be suggested by combining the best MODWT function (Bl14 function) and the fitted GARCH model. Therefore, the results show that the ability of MODWT in decomposition the stock market data, highlighting the significant events which have the most highly volatile data and improving the forecasting accuracy will be showed based on some mathematical criteria such as Mean Absolute Percentage Error (MAPE), Mean Absolute Scaled Error (MASE), Root Means Squared Error (RMSE), Akaike information criterion. These results will be implemented using MATLAB software and R- software.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1137-1144
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• 2015

Accurate and robust load forecasting model is very important in power system operation. In case of short-term electric load forecasting, its result is offered as an standard to decide a price of electricity and also can be used shaving peak. For this reason, various models have been developed to improve forecasting accuracy. In order to achieve accurate forecasting result for summer season, this paper proposes a forecasting model using corrected effective temperature based on Heat Index and CDH data as inputs. To do so, we establish polynomial that expressing relationship among CDH, load, temperature. After that, we estimate parameters that is multiplied to each of the terms using PSO algorithm. The forecasting results are compared to Holt-Winters and Artificial Neural Network. Proposing method shows more accurate by 1.018%, 0.269%, 0.132% than comparison groups, respectively.

• East Asian Journal of Business Economics (EAJBE)
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• v.8 no.1
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• pp.57-69
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• 2020

Purpose - This study examines what are the asset market fluctuations in Europe and how each economic variable affects major variables, and explore the dynamics of housing and stock market through Greece. The variables under consideration are balance on current account (BCA), index of stock (STOCK), gross domestic product (GDP), housing price indices (HOUSING), M3, real rate of interest (IR_REAL) and household credits (LOAN). We investigate the functional and causal relationships between housing and stock market. Research design, data, and methodology - Vector error correction model (VECM) is used to figure out the dynamic relationships among variables. This study also contains the augmented Dickey-Fuller unit root, cointegration, Granger causality test, and impulse response function and variance decomposition analysis by EViews 11.0. Results - The statistical tests show that all variables under consideration have one unit root and there is a longterm equilibrium relationship among variables for Greece. GDP, IR_REAL, M3, STOCK and LOAN can be considered as causal factors to affect real estate market, while GDP, LOAN, M3, BCA and HOUSING can bring direct effects to stock market in Greece. Conclusions - It can be judged that the policy that affects the lending policy of financial institutions may be more effective than the indirect variable such as monetary interest rate.