• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.835-838
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• 2000

Popular methods for extracting a text region in video images are in general based on analysis of a whole image such as merge and split method, and comparison of two frames. Thus, they take long computing time due to the use of a whole image. Therefore, this paper suggests the faster method of extracting a text region without processing a whole image. The proposed method uses line sampling methods, FFT and neural networks in order to extract texts in real time. In general, text areas are found in the higher frequency domain, thus, can be characterized using FFT The candidate text areas can be thus found by applying the higher frequency characteristics to neural network. Therefore, the final text area is extracted by verifying the candidate areas. Experimental results show a perfect candidate extraction rate and about 92% text extraction rate. The strength of the proposed algorithm is its simplicity, real-time processing by not processing the entire image, and fast skipping of the images that do not contain a text.

• Journal of the Korean Home Economics Association
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• v.42 no.4
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• pp.99-118
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• 2004

This study examined different individual and environmental factors that affect children's game addiction tendency. As individual variables, game user' motivation, self-control, and self-esteem were included in the analysis. As family variables, communications with mothers, parental control of children's computer use and parental internet use were examined, as school variables, school adjustment and teacher's supervision of children's computer use, and as peer variables, peer group's attitude toward computer games were used. The sample consisted of 994 fifth and sixth grade children. Statistics and methods used for the data analysis were Cronbach's alpha, frequency, percentage, two way ANOVA, Pearson's correlation and Hierarchical Regression. Several major results were found from the analysis. First, boys were addicted more than girls. No difference was found in the addiction tendency between the 5th graders and the 6th graders. Second, game users' motivation, that is, their interest-amusement motive, avoidance motive and aggressive motive, had a positive correlation with their game addiction tendency. However, self-control and self-esteem had a negative correlation with children's game addiction tendency. Third, problematic communications with mothers and parental control of children's computer use had a positive correlation with children's game addiction tendency. Open communications with mothers had a negative correlation with children's game addiction tendency. Fourth, school adjusaent had a negative correlation with children's game addiction tendency. And peer group's attitude towards computer games had a positive correlation with children's game addiction tendency. Fifth, low self-control, peer group's attitude towards computer games, children's interest-amusement motive, avoidance motive, aggressive motive, school lesson adjustment, parental control of children's computer use and school nile adjustment were important predicting variables of boy's game addiction tendency. Avoidance motive, low self-control, interest-amusement motive, peer group's attitude towards computer games, and parental control of children's computer use were important predicting variables of girl's game addiction tendency.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.34-46
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• 2019

A method for detecting foreign substances in mould based on scatter grams was presented to protect moulds automatically during moulding production. This paper proposes a wavelet transform foreign detection method based on Monte Carlo analysis mechanism to identify foreign objects in the tube. We use the Monte Carlo method to evaluate the image, and obtain the width of the confidence interval by the deviation statistical gray histogram to divide the image type. In order to stabilize the performance of the algorithm, the high-frequency image and the low-frequency image are respectively drawn. By analyzing the position distribution of the pixel gray in the two images, the suspected foreign object region is obtained. The experiments demonstrate the effectiveness of our approach by evaluating the labeled data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.2
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• pp.109-116
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• 2014

In this paper, we propose a frequency reuse method for efficient frequency use of multi-site weather radar. Our method uses a set of orthogonal pulse compression codes and CLEAN algorithm for sidelobe interference cancellation. Computer simulation results show that performance of proposed method meet performance requirements of [1], The current S-band weather radars in South Korea use the 8 different frequency channels to avoid interference. Using proposed method, number of occupied channels can reduce from 8 to 1, the 7 frequency channels may be use for other services.

• Journal of Power Electronics
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• v.17 no.3
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• pp.601-609
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• 2017

Gallium nitride (GaN) power switching devices are promising candidates for high switching frequency and high efficiency power conversion due to their fast switching, low on-state resistance, and high-temperature operation capability. In order to facilitate the use of these new devices better, it is required to investigate the device characteristics and performance in detail preferably by comparing with various conventional silicon (Si) devices. This paper presents a comprehensive study of GaN high electron mobility transistor (HEMT) based non-isolated point-of-load (POL) synchronous buck converter operating at 2.7 MHz with a high step-down ratio (24 V to 3.3 V). The characteristics and performance of GaN HEMT and three different Si devices are analytically investigated and the optimal operating point for GaN HEMT is discussed. Zero-voltage switching (ZVS) is implemented to minimize switching loss in high switching frequency operation. The prototype circuit and experimental data support the validity of analytical and simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.497-498
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• 2011

In 21 century, we use a variety of new wireless technologies focuses on broadcasting and Communications. Because of widely spread wireless-service, demand a lot of frequency. It requires various wireless access technologies. Especially UWB, SER, Millimeter Wave etc. Among them, UWB can use wide Frequency band, because it is different from Non-traditional approach which Frequency Band Using the exclusive rights granted by. Furthermore, it does not cause interference to other existing frequency, therefore this technology is attracting attention. In this paper, describe study on a UWB technology, design about useable antenna for UWB communication.

• Journal of the Korean Home Economics Association
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• v.39 no.8
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• pp.67-80
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• 2001

The purpose of this research was to find the relationships between use of computer games, computer game addiction and middle school boy's aggression. The subjects were 511 boys of 2 middle schools in Kwang-ju, Korea. The method was self-reporting questionnaire. For data analysis, frequency distribution, percentage, Cronbach's u coefficient were estimated. ANOVA, Duncan test, Pearson's coefficient, and multiple regression analysis were used. The major findings of the research are as follows ; First, most boys(91.4%) play computer game more than once in a week. And have over 2 years computer game experience. Second, computer game addiction score and aggression score, in general, tend to be below the mean scores. Third, boys who play computer game activities of high frequency, start play computer game at earner age, spent playing longer times of computer game, and like more on-line game were addicted to the computer game more than who don't. And boys who spent playing long times on computer game were more aggressive than who don't. Fourth, the influencies of computer game activities variables on aggression were not found significantly. But the influencies of computer game addiction were found significantly.'Negative sentiment $.$ sociality' was the most influencial variable on aggression. The influncies of 'Distortion of the reality'and 'Lost of self-control' was followed.

• Journal of Power Electronics
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• v.19 no.1
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• pp.44-57
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• 2019

Recently, the use of LLCL filters for grid inverters has been suggested to give better harmonic attenuation than the commonly used L and LCL filters, particularly around the switching frequency. Nevertheless, this filter is mainly designed for constant switching frequency pulse width modulation (CSF PWM) methods. In variable switching frequency PWM (VSF PWM), the harmonic components are distributed across a wide frequency band which complicates the use of a high order filter, including LCL and LLCL filters. Recently, a confined band variable switching frequency (CB-VSF) PWM method has been proposed and demonstrated to be superior to the conventional constant switching frequency (CSF) PWM in terms of switching losses. However, the applicability of LLCL filters for this type of CB-VSF PWM has not been discussed. In this paper, the authors study the suitability of an LLCL filter for CB-VSF PWM and propose design guidelines for the filter parameters. Using simulation and experimental results, it is demonstrated that the effectiveness of an LLCL filter with CB-VSF PWM depends on the parameters of the filters as well as the designed variable frequency band of the PWM. Simulation results confirm the performance of the suggested LLCL design, which is further validated using a lab scale prototype.

• Journal of the Korean Dietetic Association
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• v.13 no.1
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• pp.73-83
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• 2007

In order to investigate the ecological factors affecting milk intake frequency of adolescents, the questionnaire survey was conducted with 929 middle and high school students living in Chungnam urban area through October and November 2004. The subjects consumed milk 8.6$\pm$6.7 times per week, other beverages 4.4$\pm$4.1 times per week and drinking water 3.7$\pm$2.1 cups per day. Of the students 77.3% took balanced meals, 72.8% ate regularly and 36.2% ate adequate amount. About 61% had breakfast everyday and nearly a half students snacked once a day. Nutritional knowledge scores about milk was 7.2$\pm$1.7 and milk attitude scores was 28.1$\pm$6.5. The subjects spent daily 1.8$\pm$1.1, 1.9$\pm$1.1, and 1.0$\pm$0.5 hours for computer use, TV watching and exercise, respectively. Milk intake frequencies were positively correlated with excercise, snack frequency, meal balance and regularity, breakfast frequency, food attitude score and milk preference, while showed negative correlationships with TV watching and computer use. Intake frequency of fruit-tasted and chocolate milk showed inverse correlation with nutritional knowledge. Subjects without either school store or vending machine took milk more frequently than those with one or both did. Of the correlated variables, milk preference was the most important influencing factor to milk intake frequency according to the stepwise linear regression analysis, which presented other 5 important influencing factors as food attitude, school vending facilities, excercise, snacking frequency and watching TV. In conclusion, the improvement of milk preference is the most important and effective way to promote milk consumption in adolescents. The favorite ways of drinking milk, nutritional benefit of milk, healthy beverage and good snacking should be taught in nutrition education. Also physical activities should be recommended to students rather than watching TV, computer use and vending facilities selling soft drinks should be limited to be established inside school.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.203-207
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• 2023

A frequency reconfigurable antenna based on graphene and used for multi-band wireless communications is presented in this article. The proposed antenna, which consists of two radiating rectangular loops with a graphene extension, is analyzed for Global Positioning System (GPS) and Iridium applications. Its operating frequency is tuned through the implementation of a layer of graphene and thereby adjusting the applied gate bias. Furthermore, the results show a novel use of graphene for microwave frequencies while achieving a frequency reconfiguration with an improvement of the impedance matching and the gain. The results also prove the importance of graphene, with its exceptional properties, for a promising future in nano-electronics.