• 한국농공학회논문집
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• 제66권1호
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• pp.49-66
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• 2024

Extreme rainfall will become intense due to climate change, increasing inundation risk to agricultural land. Hydrological and hydraulic simulations for the entire watershed were conducted to analyze the impact of climate change. Rainfall data was collected based on past weather observation and SSP (Shared Socio-economic Pathway)5-8.5 climate change scenarios. Simulation for flood volume, reservoir operation, river level, and inundation of agricultural land was conducted through K-HAS (KRC Hydraulics & Hydrology Analysis System) and HEC-RAS (Hydrologic Engineering Center - River Analysis System). Various scenarios were selected, encompassing different periods of rainfall data, including the observed period (1973-2022), near-term future (2021-2050), mid-term future (2051-2080), and long-term future (2081-2100), in addition to probabilistic precipitation events with return periods of 20 years and 100 years. The inundation area of the Aho-Buin district was visualized through GIS (Geographic Information System) based on the results of the flooding analysis. The probabilistic precipitation of climate change scenarios was calculated higher than that of past observations, which affected the increase in reservoir inflow, river level, inundation time, and inundation area. The inundation area and inundation time were higher in the 100-year frequency. Inundation risk was high in the order of long-term future, near-term future, mid-term future, and observed period. It was also shown that the Aho and Buin districts were vulnerable to inundation. These results are expected to be used as fundamental data for assessing the risk of flooding for agricultural land and downstream watersheds under climate change, guiding drainage improvement projects, and making flood risk maps.

• 대한지역사회영양학회지
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• 제21권1호
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• pp.37-52
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• 2016

Objectives: This study was performed to develop an assessment tool for middle aged women's health status based on dietary patterns, which will have practical applications in the working field of health and hygiene, aiming at improving the middle aged women's quality of life through their health improvement. Methods: As a first step, a literature review was conducted and the original data of '2008~2009 Korea Health and Nutrition Examination Survey' were reanalyzed. This analysis identified 65 preliminary questions that may be relevant to the study. After verifying the content validity by experts, the 65 questions were reduced into 51 questions. In order to secure higher validity of the candidate items, verification of their clinical validity was conducted among women aged between 45 and 60 years. Finally, an assessment tool was developed by applying weight and scoring. Results: Selected 51 questions were used to verify clinical validity and the results showed that 20 questions were relevant, nine questions ('regular meal time', 'regular amount of meal', 'intake frequency of dairy products', 'intake frequency of fruits', 'intake frequency of meat products', 'intake frequency of high cholesterol foods', 'intake frequency of salty foods', 'appetite', 'eat breakfast everyday') were related to dietary life. Eleven other questions ('self-rated health status', 'deep sleep', 'smoking', 'frequency of drinking', 'stress levels', 'health-related fitness levels', 'pounding of the heart', 'strange feelings on the skin', 'interfere with daily life', 'menopause will bring you a chance to see the life in a different perspective', and 'body mass index') were selected as valid questions. For the response scale for each question, 5 point Likert scale was used to make total 100 point score. Conclusions: This study is the first attempt to develop a health status assessment tool for middle aged women based on their dietary patterns. We conclude that this tool is expected to be a useful and practical tool in the field.

• 한국식품영양학회지
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• 제28권1호
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• pp.47-59
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• 2015

In this study, we investigated the dietary habits, snacks, and self-purchasing snacks (SPS) intake behaviors of 519 elementary school students (boys=239, girls=280). Obesity was significantly higher (p<0.05) in boys (24.8%) than in girls (14.7%) and the proportion of underweight subjects was higher compared to normal or other weight groups for both the boys and the girls. There were 7.5% of the subjects in the group that always skipped breakfast, and the main reason of skipping breakfast was insufficient time (51.9%). The snack intake frequency was once or twice per week for 23.1% of the subjects and three or four times per week for 25.1%. The SPS intake frequency was the subjects zero for 35.6% of the highest level of the responders, while 6.8% of the respondents took more than once SPS per day. 59.6% of the respondents consumed SPS due to hunger while 15.0% consumed SPS out of boredom. The SPS was purchased from supermarkets in 34.5% of the cases, from convenience stores in 24.1% and from snack corners in 20.0% of cases or from a store near school in 14.5% of the cases. Analysis of SPS behaviors according to obesity index showed that parent's opinion of 'permission to buy SPS as needed' had a significant effect in 64.5% over weight subjects compared to only 53.7% in underweight groups. The subjects who used more than 3/4 of their pocket money to buy SPS was higher in the overweight groups (16.4%) than in the underweight groups (7.0%) and normal weight groups (9.8%). The favorite snacks and SPS were milk and yogurt for 45.7% of the subjects, fruits for 42.7%, ice cream for 26.4%, fruit juices for 23.8%, sweet stuff for 16.4%, frozen dessert for 8.9%, and chocolate or candy for 8.1% in descending order. The intake frequency of milk, yogurt, and fruit juices was higher in the underweight groups, but the intake frequency of sweet stuff, frozen dessert, and chocolate or candy was higher in over weight groups. The intake of frozen dessert was more than four times higher in the overweight groups than in the underweight groups. In conclusion, dietary habits, snacks, and SPS intake behaviors were similar between the boys and the girls and obesity groups, but most students appeared to have a high preference for intake snacks and SPS. Therefore, education for appropriate snacks intake habits will be beneficial for improving their dietary habits and health.

• 한국식생활문화학회지
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• 제33권2호
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• pp.95-103
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• 2018

This study examined the relationship between the eating out behavior of families and a low-salt management by housewives in Jeonju area. Self-administered questionnaires were collected from 420 housewives. Descriptive statistical analyses was completed using SPSS v. 19.0 and Stata 13.0. The frequency of eating out and delivered food of housewives in their 20s was significantly higher than that of the older housewives (p<0.001). The high order frequency delivered foods were chicken menu and Chinese food. The determinants of the eating out menu were children's preference and meal time. The average scores of 'interest on low-salt diet', 'attitude toward a low-salt purchasing', and 'praxis a low-salt diet' were $2.70{\pm}0.95$, $3.06{\pm}1.13$, and $3.26{\pm}0.91$, respectively. The level of a low-salt management housewives in their 20s was higher than that of the older housewives (p<0.001). Regression analysis showed that various factors (e.g. age, number of children, education level, and frequency of the eating out) correlated with the low-salt diet of subjects. For the adequate eating out behavior of families and low-salt management of housewives, information and consumer education to take family-related situations into consideration are necessary.

• Structural Engineering and Mechanics
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• 제87권3호
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• pp.211-219
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• 2023

The structural health of a pipeline is usually assessed by visual inspection. In addition to the fact that this method is expensive and time consuming, inspection of the whole structure is not possible due to limited access to some points. Therefore, adopting a damage detection method without the mentioned limitations is important in order to increase the safety of the structure. In recent years, vibration-based methods have been used to detect damage. These methods detect structural defects based on the fact that the dynamic responses of the structure will change due to damage existence. Therefore, the location and extent of damage, before and after the damage, are determined. In this study, fuzzy genetic algorithm has been used to monitor the structural health of the pipeline to create a fuzzy automated system and all kinds of possible failure scenarios that can occur for the structure. For this purpose, the results of an experimental model have been used. Its numerical model is generated in ABAQUS software and the results of the analysis are used in the fuzzy genetic algorithm. Results show that the system is more accurate in detecting high-intensity damages, and the use of higher frequency modes helps to increase accuracy. Moreover, the system considers the damage in symmetric regions with the same degree of membership. To deal with the uncertainties, some error values are added, which are observed to be negligible up to 10% of the error.

• 한국보건간호학회지
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• 제14권2호
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• pp.415-430
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• 2000

From March 10 to April 3, 1999. questionnaires were sent to 157 students at an university located in Hongsong. South Choongchung Province in order to find out their eating habits and exercise patterns. The analysis of the questionnaires collected reveals the followings. 1. Eating Habits 1) 76 out of total 157 respondents (48.4%) said that they skipped breakfast. The significant difference was shown in the frequency of breakfast eating based on respondents' sex. Male students had higher rate of going without breakfast (73.92%) than their female counterparts (28.41%). 2) Most respondents finished eating their meals within 20 minutes. with 58.5% spending 10 to 20 minutes. followed by 28.0% taking less than 10 minutes. 3) With respect to the frequency of eating snacks. 1 to 2 times per day came on top with 63.7%. Significant difference was shown based on sex. with male students having more frequent snacks than female students. 40.1% of those surveyed said they ate snacks because they were either bored or hungry, respectively, 67.5% took snacks after school followed by 23.6% who had snacks after dinner. 4) Concerning the frequency of taking food. 1 to 2 times per week recorded the highest mark for beta-carotine. fruits. fish. beans. milk. seaweeds and fries. As for vegetables. 6 to 7 times a week received the highest points. Males showed significantly higher frequency of taking fruits than females. while the opposite was true for beans. 5) More than 50% of the respondents chose rice and fruits as the food they could eat really well. All those surveyed ate fruits and vegetables. More than 10% of students said they did not eat donut. chocolate. candies. fries. coke and clear carbonated beverage. milk. ham and sausage. The food that revealed significant difference based on sex included ramyon, coke and clear carbonated beverages, ham and sausage, yogurt and milk, with males showing greater preference than their female counterparts. 6) The most preferred by respondents was spicy taste (49.04%), followed by sour (36.31%), sweet (25.48%), and salty tastes(21.1%). Those surveyed shunned sweet taste the most (21.02%), followed by sour (14.65%), spicy (8.92%), salty (5.10%) tastes. 2. Workout Patterns 1) 14.01% of the respondents said they took exercise. Based on sex, males showed significantly higher rate of 21.74% than 7.95% of females. Those who took exercise did so mostly three times a week. With regard to the time spent on workout. 'within 2 hours' received the highest points. Soccer was found to be the most popular sport among the respondents. The above analysis demonstrated that the students surveyed selected relatively sound answers in the categories of the food preference and taste. However. some skipped breakfast and liked eating snacks. and most did not take exercise, which may raise health problems including the weight increase. Therefore, ways should be devised to tackle such problems to ensure healthy lives.

• 소성∙가공
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• 제22권6호
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• pp.317-322
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• 2013

A radio frequency(R/F) switch connector is widely used in wireless devices such as mobile phone and navigator to check defects of the circuit board of product. The R/F switch connector shell plays a role in protecting the switch connector. Previously, this part was machined using a turning, which is time-consuming and has poor material utilization. Furthermore, the workpiece material of brass containing lead that has excellent machinability has environmentally regulated during recent years. The purpose of the current study was to develop the connector shell by forming through progressive dies including embossing, burring and forging process in order to achieve higher productivity and dimensional accuracy without tool failure. To accomplish this objective, a strip layout was designed and finite element (FE) analysis was performed for each step in the process. Try-out for the connector shell was conducted using progressive die design based on FE-analysis results. Dimensional accuracy of developed part was investigated by scanning electron microscopy. The result of the investigation for the dimensions of the formed connector shell showed that the required dimensional accuracy was satisfied. Moreover, productivity using the progressive die increased four times compared to previous machining process.

• 융합신호처리학회논문지
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• 제23권3호
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• pp.137-142
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• 2022

해마다 야생동물이 인간의 거주지에 출몰하는 횟수가 증가하여 재산 및 인명 피해가 증가하고 있다. 특히, 고속도로나 농가에 야생동물이 출몰하는 경우에 그 피해가 더 심하다. 이런 문제점을 해결하기 위해 고속도로에는 생태통로와 유도펜스를 설치하였다. 또한, 농가에서도 문제를 해결하기 위해 센서를 이용한 경적 퇴치기, 그물망 설치, 배설물로 퇴치 하는 등방법을 쓰고 있으나 고가의 비용이 들며 그 효과가 높지 않다. 본 논문에서는 AI 기반 영상분석 방법인 YOLO(You Only Live Once)를 이용하여 유해동물을 실시간 분석하여 오작동을 줄였고, 퇴치장치로 고휘도 LED와 초음파 주파수 스피커를 이용였다. 스피커는 동물들만 들을 수 있는 가청주파수를 출력하여 야생동물만 퇴치하도록 효율성을 높였다. 제안하는 시스템은, 경제적으로 설치할 수 있도록 범용 보드를 사용하여 설계되어 있으며 기존의 센서를 이용한 장치들보다 감지 성능이 높다.

• Journal of Information Processing Systems
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• 제12권1호
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• pp.46-56
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• 2016

Dynamic textures are videos that exhibit a stationary property with respect to time (i.e., they have patterns that repeat themselves over a large number of frames). These patterns can easily be tracked by a linear dynamic system. In this paper, a model that identifies the underlying linear dynamic system using wavelet coefficients, rather than a raw sequence, is proposed. Content based threshold filtering based on Set Partitioning in a Hierarchical Tree (SPIHT) helps to get another representation of the same frames that only have low frequency components. The main idea of this paper is to apply SPIHT based threshold filtering on different bands of wavelet transform so as to have more significant information in fewer parameters for singular value decomposition (SVD). In this case, more flexibility is given for the component selection, as SVD is independently applied to the different bands of frames of a dynamic texture. To minimize the time complexity, the proposed model is implemented on a graphics processing unit (GPU). Test results show that the proposed dynamic system, along with a discrete wavelet and SPIHT, achieve a highly compact model with better visual quality, than the available LDS, Fourier descriptor model, and higher-order SVD (HOSVD).

• Journal of Power Electronics
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• 제17권1호
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• pp.200-211
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• 2017

Conventional boost-full-bridge and boost-hybrid-bridge two-stage inverters are widely applied in order to adapt to the wide dc input voltage range of photovoltaic arrays. However, the efficiency of the conventional topology is not fully optimized because additional switching losses are generated in the voltage conversion so that the input voltage rises and then falls. Moreover, the electrolytic capacitors in a dc-link lead to a larger volume combined with increases in both weight and cost. This paper proposes a higher efficiency inverter with time-sharing synchronous modulation. The energy transmission paths, wheeling branches and switching losses for the high-frequency switches are optimized so that the overall efficiency is greatly improved. In this paper, a contrastive analysis of the component losses for the conventional and proposed inverter topologies is carried out in MATLAB. Finally, the high-efficiency under different switching frequencies and different input voltages is verified by a 3 kW prototype.