• Journal of the Korea Society of Computer and Information
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• v.28 no.3
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• pp.167-175
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• 2023

In the context of COVID-19, this study was conducted to study how college students' earned grades and average grade point averages changed according to face-to-face and non-face-to-face classes. For this study, grade data was extracted using an access database. For the study, 152 students during the 3rd semester were compared and analyzed the grade point average, average grade point average, midterm exam, final exam, assignment score, and attendance score of students who participated in non-face-to-face and face-to-face classes. As an analysis method, independent sample t-test statistical processing was performed. It was concluded that the face-to-face class students had better grades and average GPA. As a result, the face-to-face class students showed 4.39 points higher than the non-face-to-face class students, and the average grade value was 0.6642 points higher. As a result of the comparative analysis, it was statistically significant, and the face-to-face class averaged 21.22 and the non-face-to-face class had 16.83 points. In conclusion, it was confirmed that face-to-face students' grades were generally higher than those of non-face-to-face students, and that face-to-face students showed higher participation in class.

• PNF and Movement
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• v.21 no.2
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• pp.171-183
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• 2023

Purpose: The purpose of this study was to compare universal goniometry (UG), which is commonly used in clinical practice to measure the range of motion (ROM) of finger joints with a wearable soft sensor glove, and to analyze the reliability to determine its usefulness. Methods: Ten healthy adults (6 males, 4 females) participated in this study. The metacarpophalangeal joint (MCP), interphalangeal joint (IP), and proximal interphalangeal joint (PIP) of both hands were measured using UG and Mollisen HAND soft sensor gloves during active flexion, according to the American Society for Hand Therapists' measurement criteria. Measurements were taken in triplicate and averaged. The mean and standard deviation of the two methods were calculated, and the 95% limits of agreement (LOA) of the measurements were calculated using the intraclass correlation coefficient (ICC) and Bland-Altman plot to examine the reliability and discrepancies between the measurements. Results: The results of the mean values of the flexion angles for the active range of motion (AROM) of the finger joints showed large angular differences in the finger joints, except for the MCP of the thumb. In the inter-rater reliability analysis according to the measurement method, the ICC (2, 1) value showed a low level close to 0, and the mean difference by the Bland-Altman plot showed a value greater than 0, showing a pattern of discrepancy. The 95% LOA had a wide range of differences. Conclusion: This study is a preliminary study investigating the usefulness of the soft sensor glove, and the reliability analysis showed a low level of reliability and inconsistency. However, if future studies can overcome the limitations of this study and the technical problems of the soft sensor glove in the development stage, it is suggested that the measurement instrument can show more accurate measurement and higher reliability when measuring ROM with UG.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.91-101
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• 1993

To predict accurately the thermal hydraulic behavior of light water reactors during normal or abnormal operation, the accurate estimation of the void distribution is required. Up to date, many techniques for predicting void fraction of two-phase flow systems have been suggested. Among these techniques, the drift-flux model is widely used because of its exact calculation ability and simplicity. However, to get more accurate prediction of void fraction using drift-flux model, slip and flow regime effects must be considered more properly In the drift-flux method, these two effects are accounted for by two drift-flux parameters ; $C_{o}$ and (equation omitted). At earlier stage, $C_{o}$ is measured in a circular tube. In this study, $C_{o}$ is experimentally determined by measuring local void fraction and vapor velocity distribution in a rectangular subchannel having 4 heating rods which simulates nuclear subchannels. The measurements are peformed with two-electrical conductivity probes which are known to be adequate for measuring local parameters. The experiments are performed at low flow rate and the system pressure less than 3 atmo spheric pressure. In this experiment, (equation omitted), is not measured, but quoted from well-known empirical correlation to formulate $C_{o}$. Finally, $C_{o}$ is expressed as a function of channel averaged void fraction. fraction.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.519-528
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• 2023

The aim of this study was to enhance the flow rate and noise performance of a centrifugal pump in dishwashers by designing an optimized impeller shape through numerical and experimental investigations. To evaluate the performance of the target centrifugal pump, experiment was conducted using a pump performance tester and noise experiment was carried out in a semi-anechoic chamber with microphones and a reflecting wall behind the dishwasher. Through the use of advanced computational fluid dynamics techniques, numerical simulations were performed to analyze the flow and aeroacoustics performance of our target centrifugal pump impeller. To achieve this, numerical simulations were carried out using the Reynolds-Average Navier-Stokes equations and Ffowcs-Willliams and Hawkings equations as governing equations. In order to ensure the validity of numerical methods, a thorough comparison of numerical results with experimental results. After having confirmed the reliability of the current numerical method of this study, the optimization of the target centrifugal pump impeller was conducted. An improvement in flow rate was confirmed numerically, and a manufactured proto-type of the optimized model was used for experimental investigation. Furthermore, it was observed that by applying the fan law, we could effectively reduce noise levels without reducing the flow rate.

• Human Ecology Research
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• v.61 no.4
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• pp.673-686
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• 2023

The purpose of this study was to identify home economics (HE) teachers' concerns about and perceptions of HE education using the latest technologies in the era of the 4th Industrial Revolution and to reveal whether they differ according to teachers' general background variables. The questionnaire survey method to measure HE teachers' concerns and perceptions of HE education using the latest technologies in the era of the 4th Industrial Revolution was conducted online using the Google Questionnaire from which 150 responses were received. The main results were as follows. Firstly, HE teachers scored an average of 3.46 out of 5 for the latest technology. Among these interests in the latest technology, interest in "augmented reality and virtual reality technologies" scored the highest at an average of 3.80, while interest in "neural network machine learning" (2.78) was low. HE teacher's concerns about HE education using the latest technologies in the era of the 4th Industrial Revolution were high, with an average score of 4.40. Among these concerns for the latest technology, "concern about the results of HE education using the latest technology" scored the highest at 4.53. HE teachers' anxiety about the latest teaching technology in the era of the 4th Industrial Revolution was moderate, averaging 3.05. The highest form of anxiety was "anxiety about the impact on the job" (4.03) and the lowest was fear of "the disappearance of the teacher's job" (2.50). HE teachers' innovation resistance to the latest teaching technology was low at 2.18. Expectations of the latest technology in HE classes in the era of the 4th Industrial Revolution averaged 3.85, slightly higher than the middle of 3.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.19-28
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• 2020

This study was conducted to compare the agronomic characteristics and productivity according to the species and varieties of winter forage crops in reclaimed land. Winter forage crops used in this study were developed in National Institute of Crop Science, RDA. Oats ('Samhan', 'Jopung', 'Taehan', 'Dakyung' and 'Hi-early'), forage barley ('Yeongyang', 'Yuyeon', 'Yujin', 'Dacheng' and 'Yeonho'), rye ('Gogu', 'Jogreen' and 'Daegokgreen') and triticale ('Shinyoung', 'Saeyoung', 'Choyoung', 'Sinseong', 'Minpung' and 'Gwangyoung') were planted in the reclaimed land of Sihwa district in Hwaseong, Gyeonggi-do in the autumn of 2018 and cultivated using each standard cultivation method, and harvested in May 2019(oat and rye: 8 May, barley and triticale: 20 May.) The emergency rate was the lowest in rye (84.4%), and forage barley, oat and triticale were in similar levels (92.8 to 98.8%). Triticale was the lowest (416 tiller/㎡) and oat was the highest (603 tiller/㎡) in tiller number. Rye was the earliest in the heading date (April 21), triticale was April 26, and oat and forage barley were in early May (May 2 and May 5). The plant height was the highest in rye (95.6 cm), and triticale and forage barley was similar (76.3 and 68.3cm) and oat was the lowest (54.2 cm). Dry matter(DM) content of rye was the highest in the average of 46.04% and the others were similar at 35.09~37.54%. Productivity was different among species and varieties, with the highest dry matter yield of forage barley (4,344 kg/ha), oat was similar to barley, and rye and triticale were lowest. 'Dakyoung' and 'Hi-early' were higher in DM yield (4,283 and 5,490 kg/ha), and forage barley were higher in 'Yeonho', 'Yujin' and 'Dacheng' varieties (4,888, 5,433 and 5,582 kg/ha). Crude protein content of oat (6.58%) tended to be the highest, and TDN(total digectible nutrient) content (63.61%) was higher than other varieties. In the RFV(relative feed value), oats averaged 119, while the other three species averaged 92~105. The weight of 1,000 grain was the highest in triticale (43.03 g) and the lowest in rye (31.61 g). In the evaluation of germination rate according to the salt concentration (salinity), the germination rate was maintained at about 80% from 0.2 to 0.4% salinity. The correlation coefficient between germination and salt concentration was high in oat and barley (-0.91 and -0.92) and lowest in rye (-0.66). In conclusion, forage barley and oats showed good productivity in reclaimed land. Adaptability is also different among varieties of forage crops. When growing forage crops in reclaimed land, the selection of highly adaptable species and varieties was recommended.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.7-17
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• 2005

The determination of seismic velocities in refractors for near-surface seismic refraction investigations is an ill-posed problem. Small variations in the computed time parameters can result in quite large lateral variations in the derived velocities, which are often artefacts of the inversion algorithms. Such artefacts are usually not recognized or corrected with forward modelling. Therefore, if detailed refractor models are sought with model based inversion, then detailed starting models are required. The usual source of artefacts in seismic velocities is irregular refractors. Under most circumstances, the variable migration of the generalized reciprocal method (GRM) is able to accommodate irregular interfaces and generate detailed starting models of the refractor. However, where the very-near-surface environment of the Earth is also irregular, the efficacy of the GRM is reduced, and weathering corrections can be necessary. Standard methods for correcting for surface irregularities are usually not practical where the very-near-surface irregularities are of limited lateral extent. In such circumstances, the GRM smoothing statics method (SSM) is a simple and robust approach, which can facilitate more-accurate estimates of refractor velocities. The GRM SSM generates a smoothing 'statics' correction by subtracting an average of the time-depths computed with a range of XY values from the time-depths computed with a zero XY value (where the XY value is the separation between the receivers used to compute the time-depth). The time-depths to the deeper target refractors do not vary greatly with varying XY values, and therefore an average is much the same as the optimum value. However, the time-depths for the very-near-surface irregularities migrate laterally with increasing XY values and they are substantially reduced with the averaging process. As a result, the time-depth profile averaged over a range of XY values is effectively corrected for the near-surface irregularities. In addition, the time-depths computed with a Bero XY value are the sum of both the near-surface effects and the time-depths to the target refractor. Therefore, their subtraction generates an approximate 'statics' correction, which in turn, is subtracted from the traveltimes The GRM SSM is essentially a smoothing procedure, rather than a deterministic weathering correction approach, and it is most effective with near-surface irregularities of quite limited lateral extent. Model and case studies demonstrate that the GRM SSM substantially improves the reliability in determining detailed seismic velocities in irregular refractors.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.4
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• pp.218-233
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• 2022

The long-term (1986~2020) predictability of the number of days of heat and cold damages for each growth stage of soybean is evaluated using the daily maximum and minimum temperature (Tmax and Tmin) data produced by Pusan National University Coupled General Circulation Model (PNU CGCM)-Weather Research and Forecasting (WRF). The Predictability evaluation methods for the number of days of damages are Normalized Standard Deviations (NSD), Root Mean Square Error (RMSE), Hit Rate (HR), and Heidke Skill Score (HSS). First, we verified the simulation performance of the Tmax and Tmin, which are the variables that define the heat and cold damages of soybean. As a result, although there are some differences depending on the month starting with initial conditions from January (01RUN) to May (05RUN), the result after a systematic bias correction by the Variance Scaling method is similar to the observation compared to the bias-uncorrected one. The simulation performance for correction Tmax and Tmin from March to October is overall high in the results (ENS) averaged by applying the Simple Composite Method (SCM) from 01RUN to 05RUN. In addition, the model well simulates the regional patterns and characteristics of the number of days of heat and cold damages by according to the growth stages of soybean, compared with observations. In ENS, HR and HSS for heat damage (cold damage) of soybean have ranged from 0.45~0.75, 0.02~0.10 (0.49~0.76, -0.04~0.11) during each growth stage. In conclusion, 01RUN~05RUN and ENS of PNU CGCM-WRF Chain have the reasonable performance to predict heat and cold damages for each growth stage of soybean in South Korea.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.337-343
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• 2014

Purpose : The aim of this study is to evaluate unwanted scattered dose to ovary by scattering and leakage generated from treatment fields of Tomotherapy for childbearing woman with breast cancer. Materials and Methods : The radiation treatments plans for left breast cancer were established using Tomotherapy planning system (Tomotherapy, Inc, USA). They were generated by using helical and direct Tomotherapy methods for comparison. The CT images for the planning were scanned with 2.5 mm slice thickness using anthropomorphic phantom (Alderson-Rando phantom, The Phantom Laboratory, USA). The measurement points for the ovary dose were determined at the points laterally 30 cm apart from mid-point of treatment field of the pelvis. The measurements were repeated five times and averaged using glass dosimeters (1.5 mm diameter and 12 mm of length) equipped with low-energy correction filter. The measures dose values were also converted to Organ Equivalent Dose (OED) by the linear exponential dose-response model. Results : Scattered doses of ovary which were measured based on two methods of Tomo helical and Tomo direct showed average of $64.94{\pm}0.84mGy$ and $37.64{\pm}1.20mGy$ in left ovary part and average of $64.38{\pm}1.85mGy$ and $32.96{\pm}1.11mGy$ in right ovary part. This showed when executing Tomotherapy, measured scattered dose of Tomo Helical method which has relatively greater monitor units (MUs) and longer irradiation time are approximately 1.8 times higher than Tomo direct method. Conclusion : Scattered dose of left and right ovary of childbearing women is lower than ICRP recommended does which is not seriously worried level against the infertility and secondary cancer occurrence. However, as breast cancer occurrence ages become younger in the future and radiation therapy using high-precision image guidance equipment like Tomotherapy is developed, clinical follow-up studies about the ovary dose of childbearing women patients would be more required.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.238-246
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• 1994

This experiment was carried out to determine the effects of seeding date and fall harvest method on the growth characteristics, forage yield and quality of winter rye(Seca1e cereale L.) at the forage experimental field, College of Agriculture and Life Sciences, SNU, Suweon from 5 September 1992 to 21 May 1993. The experiment was arranged in a split plot design with three replications. Main plots consisted of three harvests, no defoliation, cutting and grazing. Sub-plots consisted of seeding dates, early(5 September), mid(25 September) and late(l0 October). The results obtained are summari7d as follows; I . A 3-day difference in the first heading of rye was observed between no defoliation and fall grazing, while there was a 6day difference between early and late seeding dates. Therefore, the effect of seeding dates on the fist heading date of rye was larger than that of fall harvest methods. 2. CP content of rye with fall grazing was slightly higher averaged 16.5% compared with both fall cutting and no defoliated 1ye(15.6%). Mean CP content of rye at the early, mid and late seeding dates was 14.2, 14.5 and 19.1 %, respectively. 3. ADF content of rye was slightly higher with both fall cutting(29.99) and no defoliation(29.5%) than that of fall grazing(28.0%). ADF content of rye at the early, mid and late seeding dates was 30.7, 29.1 and 27.7%, respectively. Effect of fall harvest methods and seeding dates on NDF content of rye were similar to the observations made on ADF. 4. RFV and IVDMD of rye were lower with both no defoliation and fall cutting than fall grazing. but those of rye slightly increased with seeding dates progressed. 5. Dry matter yield of rye was the highest of 6,779 kg/ha with fall cutting, while the lowest yield of 6,240 kg/ha was obtained from no defoliation But no significant difference was found among the harvest methods. Dry matter yield of rye was significantly declined with later seedings. It is concluded that the highest forage yield of rye be possible from two harvest systems of fall and spring with earlier seeding rather than from one harvest system of spring.