• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.1
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• pp.35-41
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• 2020

Fast Fourier transform (FFT) processors have been widely used in various application such as communications, image, and biomedical signal processing. Especially, high-performance and low-power FFT processing is indispensable in OFDM-based communication systems. This paper presents a novel radix-26 FFT algorithm with low computational complexity and high hardware efficiency. Applying a 7-dimensional index mapping, the twiddle factor is decomposed and then radix-26 FFT algorithm is derived. The proposed algorithm has a simple twiddle factor sequence and a small number of complex multiplications, which can reduce the memory size for storing the twiddle factor. When the coefficient of twiddle factor is small, complex constant multipliers can be used efficiently instead of complex multipliers. Complex constant multipliers can be designed more efficiently using canonic signed digit (CSD) and common subexpression elimination (CSE) algorithm. An efficient complex constant multiplier design method for the twiddle factor multiplication used in the proposed radix-26 algorithm is proposed applying CSD and CSE algorithm. To evaluate performance of the previous and the proposed methods, 256-point single-path delay feedback (SDF) FFT is designed and synthesized into FPGA. The proposed algorithm uses about 10% less hardware than the previous algorithm.

• Journal of Korea Water Resources Association
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• v.50 no.11
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• pp.769-779
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• 2017

As the occurrence of drought is recently on the rise, the reliable drought forecasting is required for developing the drought mitigation and proactive management of water resources. This study developed a probabilistic hydrological drought forecasting method using the Bayesian Networks and drought propagation relationship to estimate future drought with the forecast uncertainty, named as the Propagated Bayesian Networks Drought Forecasting (PBNDF) model. The proposed PBNDF model was composed with 4 nodes of past, current, multi-model ensemble (MME) forecasted information and the drought propagation relationship. Using Palmer Hydrological Drought Index (PHDI), the PBNDF model was applied to forecast the hydrological drought condition at 10 gauging stations in Nakdong River basin. The receiver operating characteristics (ROC) curve analysis was applied to measure the forecast skill of the forecast mean values. The root mean squared error (RMSE) and skill score (SS) were employed to compare the forecast performance with previously developed forecast models (persistence forecast, Bayesian network drought forecast). We found that the forecast skill of PBNDF model showed better performance with low RMSE and high SS of 0.1~0.15. The overall results mean the PBNDF model had good potential in probabilistic drought forecasting.

• Journal of Korea Water Resources Association
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• v.39 no.3 s.164
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• pp.261-274
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• 2006

This study performs a daily long-term runoff analysis for 30 years to forecast medium- and long-term probabilistic reservoir inflows on the Soyang River basin. Snowmelt is computed by Anderson's temperature index snowmelt model and potenetial evaporation is estimated by Penman-combination method to produce input data for a rainfall-runoff model. A semi-distributed TOPMODEL which is composed of hydrologic rainfall-runoff process on the headwater-catchment scale based on the original TOPMODEL and a hydraulic flow routing model to route the catchment outflows using by kinematic wave scheme is used in this study It can be observed that the time variations of the computed snowmelt and potential evaporation are well agreed with indirect observed data such as maximum snow depth and small pan evaporation. Model parameters are calibrated with low-flow(1979), medium-flow(1999), and high-flow(1990) rainfall-runoff events. In the model evaluation, relative volumetric error and correlation coefficient between observed and computed flows are computed to 5.64% and 0.91, respectively. Also, the relative volumetric errors decrease to 17% and 4% during March and April with or without the snowmelt model. It is concluded that the semi-distributed TOPMODEL has well performance and the snowmelt effects for the long-term runoff computation are important on the study area.

• Journal of Nutrition and Health
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• v.38 no.10
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• pp.827-835
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• 2005

The purpose of this study was to investigate the relation among mineral intakes, blood pressure, and blood lipids for health management of Korean adults over 20 years old. Subjects were recruited from the district where they lived, which included rural (Yoju, n = 137) , coastal (Taean, n = 100) , and urban district (Suwon, n : 117) . hnthropornekical measurement, blood pressure measurement, dietary intake assessment using 24-hour recall method, and blood collection and analysis of blood lipids were conducted. The average age, height, weight, and BMI were 54.1 years, 168.5 cm, 67.3 kg, and 24.5 kg/$m^{2}$ for men and 53.9 years,153.8 cm,59.2 kg, and 25.0 kg/$m^{2}$ for women, respectively. The mean daily intakes of total food and energy were 1219.1 g and 1740.9 kcal for men and 1071.3 g and 1432.6 kcal for women. The mineral intakes of men and women were 448.5 mg and 400.4 mg for calcium,955.3 mg and 803.7 mg for phosphorus, 13.3 mg and 11.1 mg for iron, 4302.8 mg and 3393.3 mg for sodium,2588.0 mg and 2264.9 mg for potassium, and 8.9 mg and 7.3 mg for zinc. The daily intakes of energy, calcium, zinc, vitamin $B_{2}$, and vitamin I were $76.1\%$, $60.1\%$, $73.1\%$, $68.6\%$, and $80.4\%$ of RDAs, respectively. The intakes of energy, calcium, zinc, vitamin $B_{2}$ and I were not meet Korean RDAs. Especially, calcium, zinc, and vitamin $B_{2}$ were less than $75\%$ of RDAs. Blood pressure of the subjects was 128.3/75.5 mmHg for men and 124.1/73.7 mmHg for women. Serum lipids of men and women were 180.2 mg/dL and 184.9 mg/dL for total cholesterol, 160.8 mg/dL and 137.6 mg/dL for triglyceride,41.5 mg/dL and 44.7 mg/dL for HDL-cholesterol,106.6 mg/dL and 112.7 mg/dL for LDL-cholesterol, and 3.5 and 3.3 for atherogenic index. While serum triglyceride and AI of men was significantly higher, HDL-cholesterol was lower than those of women. In the relation among mineral intakes, blood pressure, and serum lipids, we found a significantly negative correlation of intakes of calcium, calcium/phosphorus, calcium density with systolic blood pressure. There were significantly negative correlation between intake of calcium/phosphorus and serum cholesterol, calcium density and serum cholesterol, sodium intake and serum HDL-cholesterol. Based on these results, we concluded that high intakes of calcium, calcium/phosphorus and low sodium intake were associated with favorable blood pressure and serum lipid profiles in adult men and women. (Korean J Nutrition 38(10): 827$\sim$835,2005)

• Journal of Nutrition and Health
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• v.47 no.3
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• pp.193-205
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• 2014

Purpose: This study was conducted in order to investigate nutrient and food intake status and dietary quality in Korean adults according to nutrition label utilization. Methods: We analyzed data from the combined 2010-2011 KNHANES (Korean National Health and Nutrition Examination Survey). The analysis included 8190 adults aged 19 to 64 years. In this study, according to nutrition label utilization, we classified the subjects according to the "non-utilization of nutrition label (NUNL)" group (male, n = 2716, female, n = 3147), "identification of nutrition label (INL)" group (male, n = 143, female, n = 330), and "Utilization of nutrition label (UNL)" group (male, n = 363, female, n = 1491). Nutrient and food group intake, NAR (nutrient adequacy ratio), MAR (mean adequacy ratio), and INQ (index of nutritional quality) were analyzed using data from the 24-recall method. Results: Results of this study showed that subjects in the NUNL group were significantly more likely to drink alcohol compared with the other two groups. The NUNL group showed a significantly higher frequency of consuming instant noodles, Soju (male), and carbonated drink (female) than the UNL group, whereas the NUNL group showed a significantly lower frequency of consuming milk, soymilk, and yogurt than the UNL group. In addition, regarding diet quality (NAR and INQ), significantly lower vitamin $B_2$, vitamin C, and calcium was observed in the NUNL group compared with the UNL group. For both male and female, significantly higher MAR was observed in the UNL group than in the NUNL group. The NUNL group showed significantly lower consumption of milk compared to the UNL group. Conclusion: Good dietary practice such as referring to nutrition labels and its influence can affect the quality of nutritional intake and selection of food, while it can also provide basic data for specific nutrition education regarding use of nutrition labeling.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.23-36
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• 2012

This study aims to think about the problem of dolmens: the reasons for the presence of dolmens and how to construct it, at the point of view of geographical and geomorphological. The subjects of this study is the dolmens which locate between at Dogok Hyosanri and Chunyang Daesinri Hwasoon-gun, Jeonlanamdo. The study areas in Hyosanri, Daesinri has been observed as follows. First, the long axis direction of Dolmen upper stone and the slope one are the same. Second, tor, block stream, hockey stick, etc. Third, Composition of the soil silt> sand> clay is distributed in the order. Forth, The soil of high quality silt and the roundness of angular, sub-angular-level and the high frequency, peaks of quarts and illite clay minerals show. Fifth, in the result of $SiO_2/Al_2O_3$, $SiO_2/R_2O_3$, and CIA(Chemical Index of Alteration), Hyosanri, Daesinri areas show mechanical weathering was dominant and chemical weathering environment was not being progressed. The blocks used in construction of dolmens had moved to the bottom of slopes by mass movement such as solifluction then them which had been placed in the position seem to be used by people of Bronze. Based on the above results, the process of construction of dolmens can be estimated as follows. They would dig up the ground under the upper stone of dolmens, put the supporting stone in the place, then dig up earth, place into remains, close the obturating stones, then heal up earth.

• Korean Journal of Remote Sensing
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• v.37 no.6_3
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• pp.2027-2034
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• 2021

Using multi-temporal KOMPSAT-3/3A high-resolution satellite images, the Normalized Difference Vegetation Index (NDVI) for the area around the Fukushima daiichi nuclear power plant was determined, and the pattern of vegetation changes was analyzed. To calculate the NDVI, surface reflectance from the KOMPSAT-3/3A satellite image was used. Satellite images from four years were used, and the zones where the images overlap was designated as the area of interest (AOI) for the study, and by setting a profile passing through highly vegetated area as a data analysis method, the changes by year were examined. In addition, random points were extracted within the AOI and displayed as a box plot to quantitatively indicate change of NDVI distribution pattern. The main results of this study showed that the NDVI in 2014 was low within AOI in the vicinity of the nuclear power plant, but vegetated area continued to expand until 2021. These results were also confirmed in the change monitoring results shown in a profile or box plot. In disaster areas where access is restricted, such as the Fukushima nuclear power plant area, where it is difficult to collect field data, obtaining land cover classification products with high accuracy using satellite images is challenging, so it is appropriate to analyze them using primary outputs such as vegetation indices obtained from high-resolution satellite imagery. It is necessary to establish an international cooperation system for jointly utilizing satellite images. Meanwhile, to periodically monitor environmental changes in neighboring countries that may affect the Korean peninsula, it is necessary to establish utilization models and systems using high-resolution satellite images.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.183-194
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• 2021

In this study, the conversion factor for 2020 is estimated based on an outpatient and inpatient conversion factor separation model developed from SGR and AR by using actual medical expense data. In addition, a policy plan is proposed to calculate the values of single and multiple conversion factors for each type of medical expense, and to effectively use the conversion factor separation model as one of the means to establish a medical delivery system. The major results are as follows. First, at r=0.1, the rate of adjustment in the hospital single conversion index in 2020 was 2.0%, and the outpatient and hospitalization conversion rates for hospitals were 2.2% and 2.3%, respectively. In addition, a combination of outpatient and inpatient conversion factors can be used for the adjustment. Second, as a measure to establish a medical delivery system, instead of adjusting the addition rate, a method of interlocking the addition rate and the conversion factor is proposed. Third, it is necessary to develop a model that enables target management of volumes, in addition to the outpatient conversion factor, the inpatient conversion factor, and the adjustment coefficient.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.125-139
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• 2021

This study identifies the trend of Korean accounting researches on profit adjustment. We analyzed the abstract of accounting research articles published in Korean Citation Index (KCI) by using text mining technique. Among papers whose themes were profit adjustment, topics were divided into 4 parts: (i) Auditing and audit reports, (ii) corporate taxes and debt ratios, (iii) general management strategy of companies, and (iv) financial statements and accounting principles. Unlike the prediction that financial statements and accounting principles would be the main topic, auditing was analyzed as the most studied area. We analyzed topic trends based on the number of papers by topic, and could figure out the impact of K-IFRS introduction on profit adjustment research. By using Big Data method, this study enabled the division of research themes that have not been available in the past studies. This study enables the policy makers and business managers to learn about additional considerations in addition to accounting principles related to profit adjustment.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.320-325
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• 2021

In this study, an optimization for the production of water emulsion was designed by adding an extract of wheat sprout, which is known to contain a large amount of antioxidants. The central composite design of reaction surface analysis method (CCD-RSM) was used for the optimization process. The amount of emulsifier, emulsification time, and added amount of wheat sprout extract were selected as independent variables based on our preliminary experiments. The mean droplet size (MDS), viscosity, and emulsion stability index (ESI) were set as the responses to evaluate the stability of the emulsion. For each independent variable, the P-value and coefficient of determination were evaluated to verify the reliability of the experiments. From the result of CCD-RSM, optimum conditions for the emulsification were determined as 23.6 min, 7.7 wt.%, and 3.9 wt.% for the emulsification time, amount of emulsifier, and amount of sprout, respectively. From the optimized condition obtained, MDS, viscosity, and ESI after 7 days from reaction were estimated as 252.3 nm, 616.7 cP, and 88.7%, respectively. The overall satisfaction was 0.9137, which supported the validity of the experiments, and the error rate was measured at 0.5% or less by advancing the experiments. Therefore, an optimized process for producing an emulsion by adding the malt extract was designed by the CCD-RSM.