• Journal of the Korean Statistical Society
• /
• v.23 no.2
• /
• pp.504-512
• /
• 1994

A simple proof for the random central limit theorem is given for a family of stationary linear lattice processes, which belogn to a class of 2 dimensional random fields, applying the Beveridge and Nelson decomposition in time series context. The result is an extension of Fakhre-Zakeri and Fershidi (1993) dealing with the linear process in time series to the case of the linear lattice process with 2 dimensional indices.

• Korean Management Science Review
• /
• v.10 no.1
• /
• pp.41-58
• /
• 1993

This research analyzes the level of technological growth in Korean telecommunication industry and suggests a technology development strategy. Comparative analysis of technological growth with the advanced countries was performed based on a new technology classification scheme. Technology indices were calculated by applying Analytical Hierarchy Process(AHP). The result of the AHP was put into forecasting models to have a glimse of future growth pattern and to suggest a long-term development strategy for telecommunication technology.

• Journal of the Optical Society of Korea
• /
• v.7 no.2
• /
• pp.89-96
• /
• 2003

A new method to control the free spectral range of a long period fiber grating is proposed and theoretically analyzed. As the refractive index decreases radially outward in the silica cladding due to graded doping of fluorine, waveguide dispersion in the cladding modes was modified to result in the effective indices change and subsequently the phase matching conditions for coupling with the core mode in a long period fiber grating. Enlargement of the free spectral range in a long period fiber grating was theoretically confirmed.

• Radiation Oncology Journal
• /
• v.20 no.1
• /
• pp.73-80
• /
• 2002

Purpose : Tumor growth in a given neoplasm is the net result of cell proliferation and cell loss, and apoptosis is the most significant component of continuous cell loss in most tumors. In this study, we examined non-Hodgkin's lymphoma (NHL, n=67) immunohistochemically for the presence of Bcl-2 oncoprotein and P53 protein and compared apoptotic indices (Als) and Ki-67 proliferative indices (percentages of Ki-67 positive cells). Materials and Methods : 67 patients with NHL were evaluated : 3 low-grade and 64 intermediate-grade. The phenotype was determined in 65 cases : 47 $(70\%)$ were B cell type and 18 $(27\%)$ were T ceil type. Als and Ki-67 proliferative indices were determined immunohistochemically and the overexpression of P53 and Bcl-2 protein were also evalutated. Results : The overexpressions of Bcl-2 protein and P53 protein were found in $40\%$ (26/65) and $31\%$ (20/65). The Al ranged from $0\%\;to\;15\%$ (mean 2.16, median 1.2). Cellular Bcl-2, which counteracts apoptosis, was significantly (p=0.005) associated with Als. Ki-67 proliferative indices ranged from $1\%\;to\;91\%$ (mean 55.4), and P53 was significantly (p=0.000) associated with Ki-67 proliferative indices. A positive correlation between Als and Ki-67 proliferative indices was revealed (p=0.012) in Bcl-2 positive patients. Conclusion : In NHL, we observed a correlation between Als and Bcl-2 expression, between Ki-67 proliferative indices and P53 expression, and between Als and Ki-67 proliferative indices in Bcl-2 positive patients. Our results suggest that cell apoptosis may be inseparable from cell proliferation during tumor growth.

• Natural Product Sciences
• /
• v.13 no.3
• /
• pp.258-262
• /
• 2007

The antifungal activity of the essential oil fraction from Thymus magus, and its major component thymol, against Candida albicans was investigated in vitro and in vivo. The combined effects of the oils and clotrimazole, a commonly used antifungal drug for treatment of external candidiasis, were evaluated in this study. In experimental vaginal candidiasis the essential oil fraction of T. magnus resulted in relatively milder inhibition of fungal growth following the inoculation of test mice compared to clotrimazole. However, new fungal growth was not detected up to 12 days after cessation of treatment. In contrast, in a similar experiment using clotrimazole, C. albicans was detected in the $12^{th}$ day post-treatment with the sample. This result indicates that T. magnus oil could be a promising drug to control vaginal candidiasis. In checkerboard titer tests, the combination of clotrimazole with the essential oil fraction of T. magus or T. quinquecostatus resulted in significant synergism, with FIC indices between 0.14 and 0.27 against C. albicans, while clotrimazole combined with thymol, the major component of these oils, produced only an additive effect, with FIC indices ranging between 0.50 and 1.00. Thus, the prominent synergistic effects of clotrimazole combined with T. magus essential oil indicate that these compounds may be an effective treatment for C. albicans infections.

• Journal of Communications and Networks
• /
• v.11 no.2
• /
• pp.134-147
• /
• 2009

Tracking and exploiting instantaneous spectrum opportunities are fundamental challenges in opportunistic spectrum access (OSA) in presence of the bursty traffic of primary users and the limited spectrum sensing capability of secondary users. In order to take advantage of the history of spectrum sensing and access decisions, a sequential decision framework is widely used to design optimal policies. However, many existing schemes, based on a partially observed Markov decision process (POMDP) framework, reveal that optimal policies are non-stationary in nature which renders them difficult to calculate and implement. Therefore, this work pursues stationary OSA policies, which are thereby efficient yet low-complexity, while still incorporating many practical factors, such as spectrum sensing errors and a priori unknown statistical spectrum knowledge. First, with an approximation on channel evolution, OSA is formulated in a multi-armed bandit (MAB) framework. As a result, the optimal policy is specified by the wellknown Gittins index rule, where the channel with the largest Gittins index is always selected. Then, closed-form formulas are derived for the Gittins indices with tunable approximation, and the design of a reinforcement learning algorithm is presented for calculating the Gittins indices, depending on whether the Markovian channel parameters are available a priori or not. Finally, the superiority of the scheme is presented via extensive experiments compared to other existing schemes in terms of the quality of policies and optimality.

• MALSORI
• /
• no.62
• /
• pp.69-84
• /
• 2007

Japanese is a language having intonations, which are indicated by the relative differences in pitch heights and the accentual phrases (APs) are placed according to the changes of the accents while a break occurs on a boundary of the APs. Although a break can be predicted by using J-ToBI, which is a rule-based or statistical approach, it is very difficult to predict a break exactly due to the flexibility. Therefore, in this paper, a method which can enhance the quality of synthesized speech by reducing the errors in predicting break indices (BI), are proposed. The method is to use a new definition for the phonetic symbols, which combine the phonetic values of Japanese words with the accents information. Since a stream of defined phonetic symbols includes the information on the changes in intonations, the BI can be easily predicted by dividing the intonation phrase (IP) into several APs. As a result of an experiment, the accuracy of break generations was 98 % and the proposed method contributed itself to enhance the naturalness of synthesized speeches.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.12
• /
• pp.647-655
• /
• 2020

This study introduced income mobility analysis using pseudo-longitudinal panel data from Family Income and Expenditure Survey (FIES) to consider the dynamic process of individual's well-being through time. Since there is no comprehensive measurement of income mobility because of its dynamic process, various income mobility indices such as Chi-square, Average Jump Index, Atkinson et al. Mobility Ratio, and Shorrocks' Mobility Index were used. These indices revealed that Filipino households' income movements are more mobile than expected, and their income status improved from 2000 to 2015. As income mobility takes place, income inequality is reduced by 91.80 percent (91.80%). Furthermore, the growth effect is the main factor of income mobility. This indicates that households took the economic opportunities from economic growth to earn more. However, income mobility due to transfer effect (transfer of income from one household to another through lottery winning and borrowing) increased when the economy is not good. The higher income mobility due to growth effect compared to transfer effect, whether the economy is good or bad, means that households learned how to use their income in savings, investments, and entrepreneurship. This is the result of a successful financial literacy program of the government wherein households realized financial stability and security.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.10
• /
• pp.1257-1264
• /
• 2018

This paper proposes Autoregressive Integrated Moving Average (ARIMA)-based forecasting algorithms using meteorological indices to predict seasonal peak load. First of all, this paper observes a seasonal pattern of the peak load that appears intensively in winter and summer, and generates ARIMA models to predict the peak load of summer and winter. In addition, this paper also proposes hybrid ARIMA-based models (ARIMA-Hybrid) using a discomfort index and a sensible temperature to enhance the conventional ARIMA model. To verify the proposed algorithm, both ARIMA and ARIMA-Hybrid models are developed based on peak load data obtained from 2006 to 2015 and their forecasting results are compared by using the peak load in 2016. The simulation result indicates that the proposed ARIMA-Hybrid models shows the relatively improved performance than the conventional ARIMA model.

• Agricultural and Biosystems Engineering
• /
• v.5 no.1
• /
• pp.5-9
• /
• 2004

This study was carried out to develop methods of reducing the effect of solar illumination on pixel gray-levels of machine vision for agricultural field use. Two kinds of monochrome CCD cameras with manual and auto-iris lenses were used to take pictures within a range of 15 to 120 klux of solar illumination. A camera having more precise automatic control functions gave much better result. Four kinds of indices using pixel gray-level of the $99\%$ white DRS (diffuse reflectance standard) as a reference were tried to compensate pixel gray-levels of an image for variable illumination. Coefficients of variation of the indices within a range of illumination were used as a criterion for comparison. The study concluded that an index of (A+B)/A, where A is gray-level of the $99\%$ DRS and B is gray-level of the tested material, gave the best consistency in the range of solar illumination.