• Journal of Power Electronics
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• v.19 no.5
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• pp.1153-1161
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• 2019

A current sharing controller is proposed in this paper for parallel-connected converters. The proposed controller is based on the calculation of the magnitudes of system current space vectors. Good current distribution between parallel converters is achieved with only one Proportional-Integral (PI) compensator. The proposed controller is analyzed and the circulating current impedance is derived for paralleled systems. The performance of the new control strategy is experimentally verified using two parallel connected converters employing Space Vector Pulse Width Modulation (SVPWM) feeding a passive RL load and a 2.2 kW three-phase induction motor load. The obtained test results show a reduction in the current imbalance ratio between the converters in the experimental setup from 53.9% to only 0.2% with the induction motor load.

• Journal of the Korean Society of Safety
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• v.24 no.3
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• pp.71-78
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• 2009

During a learning process, a human being is assumed to experience knowledge-based behaviors, rule-based behaviors, and skill-based behaviors sequentially if Rasmussen was right. If any psycho-physiological symptom to those different levels can be obtained, it can be useful as a measure whether a human being is fully trained and has gotten a skill in his work. Therefore, this study aimed to draw relationships between human performance measures and psycho-physiological measures while committing a computer-simulated pointing task by utilizing the power spectrum technique of EEG data, especially with the ratio of relative beta-to-alpha band power. The result showed that, during correct responses, the ratio came to stabilize as all the performance data went stable. However, response time was not a simple linear function of task difficulty level only, but a joint function of task characteristics as well as behavior levels. Comparing relative band power ratios from errors and correct responses, activated states of one's brain could be explained, and characteristics of the task could understood. To tell that of pointing task, correlations around C3, C4, P3, P4 and 01, 02 area were significant and high in correct response cases whereas most correlation coefficients went down in error cases standing for imbalance of psycho-motor functions. Though task difficulty was the only one factor that could influence on relative band power ratio with statistical significance, it should be comprehended to mean a different way of expression indicating task characteristics since at least error-some situation could be explained with the help of relative band power ratio that absolute band power failed.

• Atmosphere
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• v.23 no.3
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• pp.307-320
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• 2013

We performed comprehensive quality control for eddy-covariance measurements from 3 farmland sites and 1 industrial site adjacent to Nakdong river. The quality control program is based on Foken and Wichura (1996) and Vicker and Mahrt (1997) and we added criteria for trend and standard deviation for scalar variables and modified criteria for non-stationarity condition of Foken and Wichura (1996) to consider random error of fluxes. The classification of data quality is designed for the raw data and the processed flux data, separately. Use of added criteria efficiently reduces the number of outlier for water vapor and $CO_2$ fluxes and use of modified criteria for non-stationarity reduces the number of outlier for scalar fluxes and increases the number of data with accepted quality for further work. Energy balance ratio is higher in farmlands than industrial site, which is due to neglect of heat storage term in industrial site. Among farmland sites, C4 site shows higher energy balance ratio than other sites. This is due to more homogeneous surface of C4 site than other farmland sites. However, energy balance ratio is very low or even negative at night. Mismatch between the flux footprint and the other energy component footprint over the heterogeneous surface is main cause for energy imbalance at night. Other possible causes are also discussed.

• Journal of Community Nutrition
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• v.7 no.2
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• pp.71-78
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• 2005

This study was performed to investigate dietary habits and nutrient intakes of college students in Gyeonggi-do area. Survey questionnaire and daily intake using 24-hour recall method were recorded by 351 college students (172 males, 179 females) . Nutrient intakes were calculated using Can-pro 2.0, from which $\%$RDA (Recommended dietary allowances), NAR (Nutrient adequacy ratio), MAR (Mean nutrient adequacy ratio), and ND (Nutrient density) were calculated to evaluate the quality of diets. Subjects answered 9 questions on dietary habits and these answers were calculated as 0, 0.5, and 1 point by frequency. Dietary habit was 39.57 $\pm$ 21.82 in male students and 42.12 $\pm$ 20.78 in female students out of total score of 100, showing higher score in female students. In the survey of dietary habits, the ratio of skipping breakfast 6 - 7 days a week in total subjects was $32.9\%$, showing a rather higher ratio of skipping breakfast, and the interest for balanced diet was as low as $13.2\%$ in total subjects. The importance of meals in total subjects was observed in the order of dinner ($47.6\%$), lunch ($40.2\%$), and breakfast($12.3\%$). In NAR of total subjects, nutrients with a score lower than 0.70 were calcium (0.64 $\pm$ 0.26), vitamin $B_2$ (0.66 $\pm$ 0.25), and vitamin C (0.69 $\pm$ 0.29) in ND of them, calcium (0.85 $\pm$ 0.43), zinc (0.89 $\pm$ 0.18), vitamin $B_2$(0.87 $\pm$ 0.34), and folic acid (0.91 $\pm$ 0.96) were nutrients with lower values. In the evaluation of nutrient intakes by the level of dietary habits, better scores of both NAR and ND were observed as the level of dietary habits was higher. There was a great difference in nutrient intakes in terms of $\%$RDA, suggesting the risk of nutritional imbalance. Based on the above results, it is considered that the improvement in dietary habits will contribute to the improvement of nutrition.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.171-181
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• 2022

Purpose: In this paper, we show our blending ratio of 10 types of Essential Oils that survives beneficial bacteria and kills harmful bacteria in the scalp, and we investigate the possibility of application of our blending ratio to the development of anti-dandruff products and the possibility of being used as a raw material for clinical beauty and customized cosmetics. Methods: The scalp microorganisms used in our study were M. furfur, S. epidermidis, E. coli, and P. nitroreducens. There are a total of 10 Essential Oils such as True Lavender, Lime, Roman chamomile, Rosemary camphor, Cedarwood, Geranium, Clove, Tea tree, Palmalosa, and Peppermint. The antibacterial test of the blended Essential Oil was carried out according to the test method of the standardized evaluation methodology of "Food and Food Additives Code". Since M. furfur is related to the growth of sebum in the scalp, in this study we used the fnLNB and the fnLNA with 20 ㎖ of whole fat cow milk added. Results: The blending ratio of EO, which inhibits dandruff-causing bacteria such as M. furfur, S. epidermidis, E. coli, and does not inhibit P. nitroreducens showing dominant growth in a healthy scalp, was B8(Clove 0.2%, Roman chamomile 0.5%, Tea tree 0.3%), B9(Geranium 0.1%, Palmarosa 0.1%, Roman chamomile 0.5%, Tea tree 0.3%), B10(Clove 0.1%, Geranium 0.1%, Palmarosa 0.1%, Roman chamomile 0.5%, Tea tree 0.2%). Conclusion: It is thought that the blending ratio of BEO obtained as a result of this study can provide a basis for use as an alternative to antibiotics in developing anti-dandruff drugs and emerge as a new alternative to solve scalp microbial imbalance. In order for EO to be used as a useful raw material for anti-dandruff preparation, researches on 1) Standardization (the effects of products differ according to the types, regions, climate, extraction methods, etc.), 2) Antimicrobial effects, 3) Safety, etc., must be established.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.331-337
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• 2023

In this paper, we propose a deep learning model to detect lumbar 3 (L3) CT images to determine the occurrence and degree of sarcopenia. In addition, we would like to propose an optimization technique that uses oversampling ratio and class weight as design parameters to address the problem of performance degradation due to data imbalance between L3 level and non-L3 level portions of CT data. In order to train and test the model, a total of 150 whole-body CT images of 104 prostate cancer patients and 46 bladder cancer patients who visited Gangneung Asan Medical Center were used. The deep learning model used ResNet50, and the design parameters of the optimization technique were selected as six types of model hyperparameters, data augmentation ratio, and class weight. It was confirmed that the proposed optimization-based L3 level extraction model reduced the median L3 error by about 1.0 slices compared to the control model (a model that optimized only 5 types of hyperparameters). Through the results of this study, accurate L3 slice detection was possible, and additionally, we were able to present the possibility of effectively solving the data imbalance problem through oversampling through data augmentation and class weight adjustment.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.724-737
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• 2013

What this research aims are as follows. First, it aims to examine the difference in gender ratio of single men and women in the entire nation and Gyeongbuk area, and also the ratio of single men in marriageable age in Gyeongbuk area by si, gun, dong, eub, and myeon, Second, the social-economical characteristics of single men in marriageable age in Gyeongbuk area, and third, the causes of problems related to marriage for single men and the solutions. As a result, it was revealed that imbalance of current gender ratio in farming area, farm villages falling behind socially and economically, young women evading marriage with young men in farming area, and difficulty of making a girlfriend, all served as the factors that made it difficult for single men to get married. It is impossible to overcome these factors by individual efforts made by single men in farming area. Therefore, these problems would be resolved by taking such measures as construction of social infrastructure in farming area in Gyeongbuk area, enhancement of status of women in farming area, and enhancement of awareness for men in farming area.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.299-309
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• 2021

Purpose : The purpose of this study was to compare the ankle pronation squat with the general squat and investigate the effect on the geun varum and the muscles around the knee. Methods : Subjects were chosen as the target for squat exercise with the distance between the knees more than 5 cm. The selected 30 students were randomly divided into 15 pronation squat group and 15 general squat group, and performed five sets movements 20 times. Global postural system (GPS) and digital goniometer were used to check the distance between the knees and the Q angle, and muscle activity was measured with EMG during squat exercise. Results: The result is as follows. First, as a result of analyzing the change in the distance between the knees, the distance between the knees decreased and the Q angle increased in the pronation squat group after exercise. Second, as a result of analyzing the change in muscle activity of the peroneus longus, the muscle activity increased in the pronation squat group after exercise, and it was more effective than the general squat group. Third, as a result of analyzing the change in the VMO (vastus medialis oblique) and VL (vastus lateralis) muscle activity ratio, the activity ratio of the pronation squat group increased after exercise, and the imbalance in the VMO/VL muscle activity was decreased. Conclusion: The pronation squat exercise applied to the ankle will greatly affect what is made into a balanced leg as decreased of the distance between knees, increased of Q angle, increased of the muscle activity of the peroneus longus and the ratio of VMO/VL.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.1
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• pp.127-137
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• 2022

PURPOSE: This study sought to evaluate muscle activity and foot pressure during gait, and balance in female college students with genu valgum. METHOD: Participants were assigned based on their Q-angle to genu valgum group greater than 20° (GVG, n = 12), unilateral genu valgum group greater than 20° (UVG, n = 11), and control group (CON, n = 13). All subjects were evaluated for balance (Trace length, C90 area, C90 angle, and the Romberg test), muscle activity (gluteus medius; GM, tensor fasciae latae; TFL, vastus medialis; VM, vastus lateralis; VL, biceps femoris; BF, gastrocnemius; GCM and tibialis anterior; TA) and foot pressure (F/F ratio, R/F ratio, Hallux, 2~5 toe, 1st MT, 2~4 MT, 5th MT, Midfoot, M/heel, and L/heel) during gait. RESULTS: Romberg test showed significantly increased loss of balance in the UVG group compared with the CON. In the forward position, the imbalance was significantly increased in the UVG and GVG groups compared to the CON. Muscle activity of VL, GCM, and TA significantly increased in the GVG group compared with the CON. Static foot pressure, 1st MT significantly increased in the GVG compared to the CON group. The 5th MT significantly decreased in the CON compared with the GVG group. The R/F ratio significantly decreased in the GVG compared to the CON group. In dynamic foot pressure, the 2~5 toe significantly increased in the GVG compared with the UVG group. The left 5th MT significantly decreased in the UVG compared with the CON and GVG groups. CONCLUSION: These results indicate that genu valgum has a negative effect on balance, muscle activity, and foot pressure during gait in female college students.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.5
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• pp.104-112
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• 2017

The CRE (Cell Range Expansion) that selects the small cell with more efficient uplink resources has been developed by 3GPP to relieve the problem of the traffic imbalance due to the power differences between macro and small cells in HetNet. In addition, ABS (Almost Blank Subframes) has been proposed to resolve the signal interference problem due to the operation CREs. This paper proposes an effective method to calculate the ABS ratio by considering the proportion of the number of UEs in CRE and macro cell ranges, as well as the number of small cells in a macro cell. The proposed method has been implemented on the LTESim simulator, and compared with previously proposed methods. The experimental results show that the proposed method can improve the throughput and packet loss ratio performances. In particular, it is also shown that CRE bias values affect those performances, and there exist effective CRE bias values to derive the best performances.