• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.179-183
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• 2000

This paper is concerned with achieving the high motion accuracy of linear motion bearing guide according to estimate accuracy average effect of bearing. Accuracy average effect can be obtained b analysis the relationship between motion error of the table and spatial frequency of the rail form error. And influences of ball diameter, ball number, and clock length on block motion error and block number on the table motion error are analyzed theoretically. In addition to, a simple experiment is performed in order to verify theoretical result.

• Journal of Power Electronics
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• 제11권1호
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• pp.59-63
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• 2011

This paper presents the modeling of the sampling effect in the p-type average current mode control. The prediction of the high frequency components near half of the switching frequency in the current loop gain is given for the p-type average current mode control. By the proposed model, the prediction accuracy is improved when compared to that of conventional models. The proposed method is applied to a buck converter, and then the measurement results are analyzed.

• 한국학교보건학회지
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• 제27권3호
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• pp.130-139
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• 2014

Purpose: The object of this study was to compare the educational effect about self-efficacy and the quality of chest compressions of Hands-only CPR and Basic CPR. Methods: It's a nonequivalent control group pre-post repeated quasi-experiment study conducted with entire fifth grade students belong to one school in H city. The study participants are 68 persons, and data were collected from December 2, 2013 to February 7, 2014. Self-efficacy was measured by 10 items, and the quality of chest compressions was measured by 5 variables which are average compression depth(mm), average rate (n/min), average count per minutes (n), abnormal placement (n), compression accuracy (%). Results: Self-efficacy of the experimental group and control group showed no significant difference but showed significant difference over time and was the highest at posttest 1 (immediately after education), the lowest at pretest (before education), middle at posttest 2 (8weeks after education) (p<.001). Experimental group was significantly higher than control group in average rate per minute. At posttest 1, experimental group was $130.0{\pm}9.38$ times, control group was $95.1{\pm}11.82$ times. At posttest2, experimental group was $124.0{\pm}14.89$ times, control group was $90.8{\pm}14.89$ times.(p<.001). Average rate (n/min) was significantly declined at control group in the quality of chest compressions over time (t=-2.400, p=.022). Average count per minute and compression accuracy were declined significantly so it were not maintained to posttest2. Conclusion: We need continuous CPR education because self-efficacy of CPR getting lower significantly over time. Hands-only CPR can't be seen as a way to increase the CPR ability of elementary school students having difficulty to perform artificial breathing. And, because the effect of education is not maintained 8wks after training, the technique centered repeated training is needed and a method which can increase compression accuracy is also needed.

• 한국건설관리학회논문집
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• 제16권1호
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• pp.101-109
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• 2015

투자에 의해 기대되는 경제적 효과는 실질할인율의 자승으로 매년 나누어서 현재가치로 전환된다. 따라서 실질할인율이 경제성 분석결과에 미치는 영향은 다른 요인들보다 크다. 실질할인율을 예측하는 기존의 일반적인 방법은 과거 특정기간의 평균값을 적용하는 것이다. 본 연구에서는 실질할인율의 예측 정확도를 향상시키기 위한 방법을 제안하였다. 먼저 실질할인율을 구성하는 기업대출 이자율과 소비자 물가지수에 영향을 미치는 경제변수들을 도출하였다. 기업대출 이자율에 영향을 주는 변수들로는 콜 금리와 환율, 소비자 물가지수에 영향을 주는 경제변수는 생산자 물가지수를 선정하였다. 다음으로 실질할인율과 선정된 변수들과의 영향관계를 검정하였다. 영향관계가 존재하는 것으로 분석되었다. 마지막으로 관련된 경제 변수들을 기반으로 2008년부터 2010년까지의 실질할인율을 예측하였다. 예측 결과의 정확도는 실측값과 평균값의 결과와 비교되었다. 실측값이 적용된 실질할인율은 -1.58%였으며, 예측 값은 -0.22%, 평균값은 6.06%으로 분석되었다. 본 연구에서 제안한 방법은 금융위기와 같은 특수 상황을 고려하지 않은 것이지만, 평균값보다 예측 정확도가 크게 우수한 것으로 분석되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.281-281
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• 2015

Shallow landslide often occurs in areas of this topography where subsurface soil water flow paths give rise to excess pore-water pressures downslope. Recent hillslope hydrology studies have shown that subsurface topography has a strong impact in controlling the connectivity of saturated areas at the soil-bedrock interface. In this study, the physically based SHALSTAB model was used to evaluate the effects of three soil thicknesses (i.e. average soil layer, soil thickness to weathered soil and soil thickness to bedrock soil layer) and subsurface flow reflecting three soil thicknesses on shallow landslide prediction accuracy. Three digital elevation models (DEMs; i.e. ground surface, weathered surface and bedrock surface) and three soil thicknesses (average soil thickness, soil thickness to weathered rock and soil thickness to bedrock) at a small hillslope site in Jinbu, Kangwon Prefecture, eastern part of the Korean Peninsula, were considered. Each prediction result simulated with the SHALSTAB model was evaluated by receiver operating characteristic (ROC) analysis for modelling accuracy. The results of the ROC analysis for shallow landslide prediction using the ground surface DEM (GSTO), the weathered surface DEM and the bedrock surface DEM (BSTO) indicated that the prediction accuracy was higher using flow accumulation by the BSTO and weathered soil thickness compared to results. These results imply that 1) the effect of subsurface flow by BSTO on shallow landslide prediction especially could be larger than the effects of topography by GSTO, and 2) the effect of weathered soil thickness could be larger than the effects of average soil thickness and bedrock soil thickness on shallow landslide prediction. Therefore, we suggest that using BSTO dem and weathered soil layer can improve the accuracy of shallow landslide prediction, which should contribute to more accurately predicting shallow landslides.

• 대한산업공학회지
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• 제30권1호
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• pp.11-16
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• 2004

Oxygen is an essential element for human beings' physical and mental activities, and in particular, plays an important role in brain functions. The present study attempted to investigate the effects of supply of highly concentrated (30%) oxygen on human ability of visuospatial cognition, compared to air of normal oxygen concentration (21%). This study sampled eight male university students (the average age: 23.5) as subjects. An equipment that supplies 21% and 30% oxygen at a constant rate of 8L/min was developed. Two types of questionnaire containing 20 questions were developed to measure the ability of visuospatial cognition, and accuracy and reaction time were calculated from the result of task performance. The average accuracy was $50.63{\pm}8.63$ [%] and $62.50{\pm}9.64$[%] for 21%and 30% oxygen respectively, and a statistically significant difference was found in the accuracy between the two types of oxygen. The average reaction time was $6.60{\pm}O.77$ [sec] and $7.23{\pm}0.69$ [sec] for 21%and 30% oxygen respectively, and a statistically significant difference was not found in the reaction time. The results showed that there is no difference in the average reaction time but the average accuracy rises with the supply of highly concentrated (30%) oxygen, indicating that the supply of highly concentrated oxygen has a partially positive effect on the ability of visuospatial cognition.

• Journal of Computing Science and Engineering
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• 제10권2호
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• pp.39-50
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• 2016

In this paper, we present a comparative study of spatial domain features for writer identification and verification with different ink width conditions. The existing methods give high error rates, when comparing two handwritten images with different pen types. To the best of our knowledge, we are the first to design the feature with different ink width conditions. To address this problem, contour based features were extracted using a chain code method. To improve accuracy at higher levels, we considered histograms of chain code and variance in bins of histogram of chain code as features to discriminate handwriting samples. The system was trained and tested for 1,000 writers with two samples using different writing instruments. The feature performance is tested on our newly created dataset of 4,000 samples. The experimental results show that the histogram of chain code feature is good compared to other methods with false acceptance rate of 11.67%, false rejection rate of 36.70%, average error rates of 24.18%, and average verification accuracy of 75.89% on our new dataset. We also studied the effect of amount of text and dataset size on verification accuracy.

• 농업과학연구
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• 제41권4호
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• pp.481-485
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• 2014

According to statistical data the past ten years, cultivation area and yield of radish are steadily decreasing. This phenomenon cause instability of radish's supply due to meteorological chage, even if radish's yield per unit area is increasing by cultivation technological development. These problems raise radish's price. So, we conducted study on meteorological factors for accuracy improvement of radish yield estimation. Panel analysis was used with two-way effect model considering group effect and time effect. As the result, we show that mixed effects model (fixed effect: group, random effects: time) was statistical significance. According to the model, a rise of one degree in the average air temperature on August will decrease radish's yield per unit area by $428kg{\cdot}10a^{-1}$ and that in the average air temperature on October will increase radish's yield per unit area by $438kg{\cdot}10a^{-1}$. The reason is that radish's growth will be easily influenced by meteorological condition of a high temperature on August and by meteorological condition of a low temperature on Octoboer.

• International journal of advanced smart convergence
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• 제11권4호
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• pp.57-67
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• 2022

The demand for personal training (PT), through which high exercise effects can be achieved within short-term, has recently increased. PT can achieve an exercise amount improvement effect, only if accurate postures are maintained upon performing PT, and exercise with inaccurate postures can cause injuries. However, research is insufficient on exercise amount comparisons and judging exercise accuracy on PT. This study proposes an exercise accuracy measurement algorithm and compares differences in exercise amounts according to exercise postures through experiments using a respiratory gas analyzer. The exercise accuracy measurement algorithm acquires Euler anglesfrom major body parts operated upon exercise through a motion device, based on which the joint angles are calculated. By comparing the calculated joint angles with each reference angle in each exercise step, the status of exercise accuracy is judged. The calculated results of exercise accuracy on squats, lunges, and push-ups showed 0.02% difference in comparison with actually measured results through a goniometer. As a result of the exercise amount comparison experiment according to accurate posture through a respiratory gas analyzer, the exercise amount was higher by 45.19% on average in accurate postures. Through this, it was confirmed that maintaining accurate postures contributes to exercise amount improvement.

• 대한치과기공학회지
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• 제46권3호
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• pp.73-83
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• 2024

Purpose: This study aimed to investigate whether the accuracy and internal porosity of removable partial denture frameworks differ depending on the build direction in the selective laser melting method. Methods: A partially edentulous maxillary study model was scanned, and the anterior-posterior palatal bar was then digitally designed. The angles formed between the z-axis and the path of the insertion and removal were divided into five groups: -60°, -30°, 0°, 30°, and 60°. For each group, three removable partial denture metal frameworks were fabricated and used as specimens. The inner surface of each sample was scanned and superimposed on the design file to obtain the root mean square (RMS) value, and the average RMS value of each group was measured. One sample was randomly selected from each group, and the equivalent diameter and sphericity of the pores were analyzed using industrial X-ray three-dimensional computed tomography. To compare statistical differences between groups, the Kruskal-Wallis test of SPSS Statistics ver. 27.0 (IBM) was used (α=0.05). Results: The average RMS values of the whole inner surface accuracy of the specimens were in the order of -60°<0°<-30°<30°<60° (p<0.05). The equivalent diameter and sphericity of internal pores were significantly different among groups (p<0.001). Conclusion: The build orientation of the selective laser melting method influences the accuracy and internal porosity of removable partial denture frameworks.