• Journal of the Korean Society of Safety
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• v.39 no.2
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• pp.65-74
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• 2024

We analyzed the relationship between the normal measurement of the seismic accelerometer (SA) and the error rate of the output voltage linear ratio to propose an evaluation method to determine whether the SA in use is measuring normally. Utilizing a test bed, the regular operation of SA in use was evaluated using acceleration data measured through impact tests since there are no regulations regarding performance testing of SA in use. For the used SA, the error rate of the output voltage linear ratio, which is a major performance criterion, was evaluated. We analyzed common characteristics of the SA that satisfied the impact test and the performance criteria of the output voltage linear ratio error rate. The results indicated that we must consider the decreasing trend and convergence of the error rate as the measurement angle increases, ensuring that the average value of the output voltage linear ratio error rate is within 1%.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.3
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• pp.163-168
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• 2011

In this paper, we proposed non-linear gamma curve algorithm for gamma correction. The previous non-linear gamma curve algorithm is generated by the least square polynomial using the Gauss-Jordan inverse matrix. However, the previous algorithm has some weak points. When calculating coefficients using inverse matrix of higher degree, occurred truncation errors. Also, only if input sample points are existed regular interval on 10-bit scale, the least square polynomial is accurately works. To compensate weak-points, we calculated accurate coefficients of polynomial using eigenvalue and orthogonal value of mat11x from singular value decomposition (SVD) and QR decomposition of vandemond matrix. Also, we used input data part segmentation, then we performed polynomial curve fitting and merged curve fitting results. When compared the previous method and proposed method using the mean square error (MSE) and the standard deviation (STD), the proposed segmented polynomial curve fitting is highly accuracy that MSE under the least significant bit (LSB) error range is approximately $10^{-9}$ and STD is about $10^{-5}$.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.845-853
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• 2014

In this study, we measured the dose reaching the OSLD dosimeter by using the regular lead apron, and air gap apron through 3 experiments, and researched the reductive effect of air gap apron on exposure dose based on the 140 keV gamma ray radiating from $^{99m}technetium$, which is the most commonly used in nuclear medicine. As a result, when the gap between the dosimeter and 0.2mm lead plate is 0 Cm, the average value of 10 dosimeters was 0.515 mSv, and when the gap between the dosimeter and lead plate is 20 Cm, the average value of 10 dosimeters was 0.138 mSv, which shows reductive effect of dose as much as 0.388 mSv. When the gap between the dosimeter and 0.5mm lead plate is 0 Cm, the average value of 10 dosimeters was 0.296 mSv, and when the gap between the dosimeter and lead plate is 20 Cm, the average value of 10 dosimeters was 0.075 mSv, which shows reductive effect of dose as much as 0.221 mSv. As we check the cumulative dosage for 3 days, the lead apron without air layer shows average 0.239 mSv, and the air gap apron shows 0.176 mSv, which is actually reduced by 0.062 mSv. As we check the cumulative dosage for a month, the lead apron without air layer shows 0.59 mSv, and the air gap apron shows 0.54 mSv, which is reduced by 0.05 mSv.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.4
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• pp.610-617
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• 2009

The aim of this study was to investigate the quality characteristics of Karedduk, Korean rice cakes, containing cactus (as Opuntia humifusa) fruit powder at a concentration of 0, 2, 4, 6 and 8% during three days of storage. The moisture content of the cooked cake just before storage ranged from 45.55～49.70%, indicating that the moisture content decreased as the amount of the powder added inceased. The L value, which is a measure of the lightness of the cake color decreased as the amount of added powder increased. In addition, the L value sharply decreased after one day of storage relative to its valve just after the cake was cooked. However, no significant changes were observed at longer storage times except at a fruit powder concentration of 2%. The a value, which is a measure of the redness, was significantly increased with an increase in the amount of added powder. The b value, which is a measure of the yellowness, was the same for all the treatments regardless of the amount of the powder added. The a and b values did not display any regular patterns in terms of the amount of powder added as a function of storage time. In regards to mechanical quality characteristics, the hardness and the gumminess of the cake just cooked tended to be increase with an increase in the amount of added powder indicating that no significant differences between the non-treatments and the treatments existed. The hardness of the cake did not change after two days of storage relative to when they were just cooked at all powder concentrations: however, the hardness of the cake after three days of storage was found to drop significantly with an increase in the amount of added powder. The cohesiveness of the cake right after cooking tended to decrease with an increase in the amount of added powder. The springiness of the cake right after it was cooked and on the second day of storage, did not significantly different as a function of powder concentration. The chewiness of the cake right after cooking increased with an increase in the amount of added powder. In the sensory test, the color and the flavor of the cake containing a powder concentration of 6% was found to be the highest. In addition and the chewiness significantly with an increase in the amount of added powder. In both taste and overall acceptability, the cake containing a powder concentration of 4% was determined to be the highest, showing no significant differences in taste relative to the cakes made with a powder concluded that it would be the best to cook Karedduk which a of cactus (Opuntia humifusa) fruit powder concentration of 4~6%.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.6
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• pp.856-868
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• 2009

This study was conducted to investigate causes for health problems among college women by analyzing factors related to their dietary habits, physical development, health habits, and blood parameters. The subjects were ages 20 to 24 years, lived in the Seoul area and were randomly selected during March, 2008 to August, 2009. The average height and weight of the overall subjects were $162.02{\pm}4.89\;cm$ and $53.96{\pm}7.00\;kg$, respectively. According to a 3-point assessment scale for the subjects' dietary habits, the average point value was 21.2. The percentage of subjects that ate breakfast daily was only 30.5%, and they omitted regular meals at least once a week. Approximately 83.5% of the subjects reported eating out often or frequently, and preferred Korean foods when they ate out. The subjects had interim meals (snacks) one or two times daily, and 40.4% of them preferred unbalanced meals. As their interim meals, among the 'good' group, ate breaded potatoes (39.3%), carbonated beverages, and ice cream (36.8%), whereas the 'poor' group, drank milk and ate dairy products (38.0%) as well as fast food and fried food (22.8%). Intakes of energy, fat, vitamins $B_2$ and $B_6$, niacin, folic acid, calcium, iron, zinc, and phosphorus were higher in the 'poor' group. The average hemoglobin level ($13.77{\pm}1.00\;g/dL$) among the subjects was within normal range; while 2.7% of subjects had hemoglobin levels under 11.1 g/dL (standard value) and were examined as anemic. The degree of interest in health was 24.5% higher among the subjects who had poor dietary habits. In contrast, among those who had good dietary habits, 49.6% reported they had no interest in regular exercise. The subjects reported that regular meals, nutrient intake, sufficient rest, and sleep as necessary to maintain health. The average amount of sleep obtained by the subjects was 6~8 hours. Among the 'poor' group, 36.2% reported that they exercised regularly, whereas 18.5% of the subjects in the 'good' group reported regular exercise (p<0.05). In conclusion, it appears necessary to provide nutrition education through teaching and to promote nutrition and health to college women so they can control their individual health status and create practicable dietary plans.

• Journal of Korean society of Dental Hygiene
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• v.11 no.6
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• pp.843-852
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• 2011

Objectives : The aims of the study were to examine perceived oral malodor and self-reported need for oral and dental care among patients receiving oral prophylaxis services and provide guidelines for developing educational programs(toothbrushing method and tongue cleaning) for oral hygiene and oral malodor prevention. Methods : The survey was administered to a sample of 462 receiving voluntary oral prophylaxis service in a dental laboratory at the J School of Public Health in Korea. The subjects were asked a range of questions related to the degrees of perceived oral malodor and concern for oral health status, as well as their demographic information and need for oral and dental treatment. Univariate analyses using Chi-square and T-test with a P-value of .05 were performed using SPSS Version 12.0 for Windows. Results : 1. Male participants reported "moderately concerned for bad breath and smell" and "I don't care bad breath and smell" 39.1% and 26.2% respectively, while more female participants were concerned for oral malodor. "moderately concerned for malodor" and" highly concerned for malodor" 41.1% and 28.5%(p<.05). a significant difference among age groups was found. 19% of young adults (less than or equal to 29 years of age) reported "highly concerned for bad breath and smell" while 36.4% of older adults (greater than or equal to 50 years of age) reported "highly concerned for bad breath and smell"(p<.05). 2. 12 non-smoking participants (3.7%) and 15 smoking participants (10.8%) reported that they have perceived bad breadth and smell (p<.05). 3. Smoking participants reported a higher degree of need for oral malodor treatment than that of non-smoking participants 88.5% and 82% respectively(p<.05). 4. The participants who did regular toothbrushing more than 3 times a day reported "no malodor", 77 % as compared to 66.7% of the participants who did regular toothbrushing 2 times a day. Toothbrushing 2 times a day reported either "moderate malodor" or "sever malodor"(p<.01). Participants with more frequent toothbrushing reported less oral and breath odor as compared participants with less frequent toothbrushing. Conclusions : The study suggested that there is a need to oral prophylaxis for prevention and toothbrushing and tongue cleaning method oral malodor care and oral health status.

• Journal of The Korean Association of Information Education
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• v.15 no.3
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• pp.483-492
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• 2011

'Learning with a robot' is now considered as one of the best candidates for STEAM education, which is recently growing its importance. Most of the 'learning with a robot' programs in elementary schools serve as afterschool classes. The students participating in the afterschool classes are mostly boys who are interested in science and robots. This paper mainly concerns that a robot can be helpful for improving students' interest in STEAM education. We divided the robot utilizable aspects into 5 areas with educational points of view; abstract concept understanding type, structure-oriented type, athletics-oriented type, intelligence-oriented type and value-orientated type. We extracted all robot utilizable subjects and units from elementary school curriculum, and developed lesson plans which can be applicable to regular classes. And we also verified them by applying into an elementary school for 5 months. As the result of the analysis, we can conclude that 'learning with a robot' can encourage students' interest in STEAM, and it is more effective for girls than boys. Finally, we discuss problems that teachers may face in using a robot for regular classes, and make suggestions about the use of a robot for STEAM education.

• Imaging Science in Dentistry
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• v.49 no.4
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• pp.273-279
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• 2019

Purpose: This study was performed to investigate the effects of energy level, reconstruction kernel, and tube rotation time on Hounsfield unit (HU) values of hydroxyapatite (HA) in virtual monochromatic images (VMIs) obtained with dual-energy computed tomography (DECT)(Siemens Healthineers, Erlangen, Germany). Materials and Methods: A bone density calibration phantom with 3 HA inserts of different densities(CTWATER^®; 0, 100, and 200 mg of HA/㎤) was scanned using a twin-beam DECT scanner at 120 kVp with tube rotation times of 0.5 and 1.0 seconds. The VMIs were reconstructed by changing the energy level (with options of 40 keV, 70 keV, and 140 keV). In order to investigate the impact of the reconstruction kernel, virtual monochromatic images were reconstructed after changing the kernel from body regular 40 (Br40) to head regular 40 (Hr40) in the reconstruction phase. The mean HU value was measured by placing a circular region of interests (ROIs) in the middle of each insert obtained from the VMIs. The HU values were compared with regard to energy level, reconstruction kernel, and tube rotation time. Results: Hydroxyapatite density was strongly correlated with HU values(correlation coefficient=0.678, P<0.05). For the HA 100 and 200 inserts, HU decreased significantly at increased energy levels(correlation coefficient= -0.538, P<0.05) but increased by 70 HU when using Hr40 rather than Br40 (correlation coefficient=0.158, P<0.05). The tube rotation time did not significantly affect the HU(P>0.05). Conclusion: The HU values of hydroxyapatite were strongly correlated with hydroxyapatite density and energy level in VMIs obtained with DECT.

• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.600-611
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• 2018

This study analyzed the effects of wage workers' job satisfaction, life satisfaction on turnover intention, and moderating effect of employment type after the global financial crisis using Korean Labor and Income Panel Study data. As a result, we found that the higher the job satisfaction is, the lower the turnover intention. However, the higher the job satisfaction and life satisfaction are, the higher the turnover intention. This is because the more satisfied with the job environment, the higher the tendency to seek better job opportunities, or the change in occupational value that favored free work. The higher the age, the higher the educational level, and the regular jobs are, the turnover intention decreased. In addition, the interaction terms of job satisfaction, job environmental satisfaction, life satisfaction, and regular employment all showed a moderating effect of employment type. However, since the results of the relationship between job satisfaction, job environmental satisfaction, life satisfaction and turnover intention, and the moderating effect may be due to limitations of measurement variables, further study is needed.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.67-85
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• 2009

This study aims to provide the research for dental technician's stress prevention and management with basic materials by understanding dental technician's psychosocial stress level and examining relevant factors. The subject of this study is 255 dental technologists who work mainly in Seoul Gyeonggi district for a month of April of 2009 and I conducted cross-sectional study through self administered survey. The contents of survey include general feature, occupational feature, health behavior feature. I used Karasek's Job Content Questionnaire, JCQ and Psychosocial well-being index, PWI-SF as means of measurement. To compare the level of dental technician's psychosocial stress, I conducted t-test and ANOVA and I measured the factors that are related with psychosocial stress symptom with step by step multiple regressive analysis. According to the result of Cronbach's a value which is yielded to verify the reliability of means of measurement, the reliability of concept is sufficient. The detailed result of this study is as follows. 1. According to the result of analyzing the stress symptom in accordance with general feature and occupational feature, those dental technologists who are older and not married, graduate from junior college, have lower position, work at university hospital or general hospital show lower stress(p<0.05). There is no difference in the level of psychosocial stress with regard to duty related feature, period of service, daily average working hours, monthly average pay. 2. With regard to health behavior feature, those dental technologists who control weight better and have meal more regularly show lower stress(p<0.05). Those dental technicians who smoke, drink liquid and take a suitable sleep show low stress but the difference does not have significance statistically. 3. With regard to the factors of stress in the workplace, those dental technicians who have lower duty related requirement, have higher duty related control ability, have higher social support, have less instability of employment and have less workload and physical burden show lower stress(p<0.05). 4. According to the result of analyzing the factors that influence dental technologist's stress symptom, social support has the most enormous influence on stress symptom. Unstable employment, regular exercise, regular eating, daily average sleeping hours and technological capacity are also important in this order. According to the result of this study, those dental technicians who have higher social support, less instability of employment, do exercise more regularly, take enough sleep more soundly and have higher technological capacity show lower psychosocial stress symptom. Therefore, to adjust appropriately the dental technician's stress and properly maintain and improve the dental technician's mental health, effective management plan that enables dental technicians to maintain smooth human relationships for dental technicians should be sought. In addition, heath education and health management for dental technicians should be given more thoroughly so that they can establish desirable health behavior in daily life.