• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.698-709
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• 2016

Free Learning Semester, the new education policy of middle schools in Korea, will be completely implemented in 2016. The purpose of this study was to explore the school experiences of middle-school students in the Free Learning Semester through qualitative approach. In-depth interview was conducted with 8 middle-school students from the purposive sampling. As a result of the analysis, 10 essential themes were identified. Themes were as follows: 'Struggling from the performance evaluation with biting the bullet', 'Great pressure on final examination that is only once a year', 'Inconvenience of career education experience', 'Higher level of friendship', 'Double face of discrimination and respect', 'Chance to adaptation between elementary and middle-school', 'Regret about fleeting time without thought', 'Ambivalence of freedom and suppression', 'Warm place with peer', 'Being pushed rehearsal wearing other's cloth'. In conclusion, the nature of lived experience of middle-school students in the Free Learning Semester is based on ambivalence of various aspects, but is predominant in 'higher level of friendship'. It suggested that the Free Learning Semester can be a positive alternative to existing education system that made students to compete each other. It is expected to be able to discuss the future policy direction using the result of this study which explored the nature of lived experience related to the Free Learning Semester.

• The Korean Journal of Community Living Science
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• v.24 no.4
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• pp.543-552
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• 2013

Physiological and subjective responses of the farmers and thermal environment during chili harvest in the open field were investigated to evaluate the thermal environments and farmers's workload. Eight career female farmers in their sixties participated as subjects both in morning work(MW, AM 9:00~10:30) and in afternoon work(AW, PM 15:00~16:30) with each lasting about 90 minutes. The results were as follows. 1) Air temperature, air humidity, globe temperature and WBGT of MW were mean $25.54^{\circ}C$, 81.82%RH, $37.72^{\circ}C$, $26.27^{\circ}C$ and AW were mean $30.63^{\circ}C$ 82.50%RH, $40.11^{\circ}C$, $30.02^{\circ}C$, respectively. By the WBGT, we evaluated that the thermal environment in the afternoon in the open field gave a thermal burden to farmers. 2) Mean skin temperature of AW($34.8{\pm}0.8^{\circ}C$) was higher than MW($33.5{\pm}1.2^{\circ}C$)(p<0.05). Clothing microclimate temperature on the chest of each work time were $31.3^{\circ}C$(MW) and $32.7^{\circ}C$(AW). Clothing microclimate humidity on the chest of each work time were over 80%RH. Heart rate were 88.5bpm(MW) and 91.7bpm(AW) respectively. 3) Farmers working in the afternoon felt uncomfortable after 45~60 min. of work and in the morning they felt uncomfortable after 90 min. of work. We evaluated that the harvesting of chilies in the open field was 'moderate work' by the physiological responses but the level of thermal burden increased over time especially in the afternoon work. It is suggested that farm workers should drink fluids between work to stay in homeostasis by sweating and to take frequent rests. Active clothing ventilation and wearing functional garments would help farm workers excrete sweat effectively.

• Journal of Environmental Health Sciences
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• v.48 no.2
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• pp.59-65
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• 2022

Background: Since people move through microenvironments rather than staying in one place, they may be exposed to both indoor and outdoor PM_2.5 concentrations. Objectives: The aim of this study was to assess the exposure level of each sub-population group and evaluate the contribution rate of the major microenvironments. Methods: Exposure scenarios for sub-population groups were constructed on the basis of a 2019 Time-Use survey and the previous literature. A total of five population groups were classified and researchers wearing MicroPEM simulated monitoring PM_2.5 exposure concentrations in real-time over three days. The exposure contribution for each microenvironment were evaluated by multiplying the inhalation rate and the PM_2.5 exposure concentration levels. Results: Mean PM_2.5 concentrations were 33.0 ㎍/m³ and 22.5 ㎍/m³ in Guro-gu and Wonju, respectively. When the exposure was calculated considering each inhalation rate and concentration, the home showed the highest exposure contribution rate for PM_2.5. As for preschool children, it was 90.8% in Guro-gu, 94.1% in Wonju. For students it was 65.3% and 67.3%. For housewives it was 98.2% and 95.8%, and 59.5% and 91.7% for office workers. Both regions had higher exposure to PM_2.5 among the elderly compared to other populations, and their PM_2.5 exposure contribution rates were 98.3% and 94.1% at home for Guro-gu and Wonju, respectively. Conclusions: The exposure contribution rate could be dependent on time spent in microenvironments. Notably, the contribution rate of exposure to PM_2.5 at home was the highest because most people spend the longest time at home. Therefore, microenvironments such as home with a higher contribution rate of exposure to PM_2.5 could be managed to upgrade public health.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.24.1-24.15
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• 2023

Background: The construction workers are vulnerable to fatigue due to high physical workload. This study aimed to investigate the relationship between overwork and heart rate in construction workers and propose a scheme to prevent overwork in advance. Methods: We measured the heart rates of construction workers at a construction site of a residential and commercial complex in Seoul from August to October 2021 and develop an index that monitors overwork in real-time. A total of 66 Korean workers participated in the study, wearing real-time heart rate monitoring equipment. The relative heart rate (RHR) was calculated using the minimum and maximum heart rates, and the maximum acceptable working time (MAWT) was estimated using RHR to calculate the workload. The overwork index (OI) was defined as the cumulative workload evaluated with the MAWT. An appropriate scenario line (PSL) was set as an index that can be compared to the OI to evaluate the degree of overwork in real-time. The excess overwork index (EOI) was evaluated in real-time during work performance using the difference between the OI and the PSL. The EOI value was used to perform receiver operating characteristic (ROC) curve analysis to find the optimal cut-off value for classification of overwork state. Results: Of the 60 participants analyzed, 28 (46.7%) were classified as the overwork group based on their RHR. ROC curve analysis showed that the EOI was a good predictor of overwork, with an area under the curve of 0.824. The optimal cut-off values ranged from 21.8% to 24.0% depending on the method used to determine the cut-off point. Conclusion: The EOI showed promising results as a predictive tool to assess overwork in real-time using heart rate monitoring and calculation through MAWT. Further research is needed to assess physical workload accurately and determine cut-off values across industries.

• Fire Science and Engineering
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• v.33 no.6
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• pp.165-172
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• 2019

This study presents the design and manufacture of a self-contained breathing apparatus SCBA wireless communication module with a multipoint simultaneous full-duplex communication system to enable communication between team members wearing the SCBA system. It is necessary for fire-fighters to wear the SCBA system during extinguishing and rescue work at the fire site. Evaluation of the team communication module confirmed the feasibility of communication over more than 500 m in the test condition based on the line of sight. By implementing the Ad-hoc function, it was confirmed that the communication distance could be extended to 128 m by automatic routing up to 3 hoc. The vertical distance inside the building for successful communication was up to the 5th floor in the open staircase and up to the 3rd floor in the partitioned staircase. Furthermore, the performance testing of the communication module assuming a fire situation, confirmed that five team members correctly recognized the standard abbreviation of fire and wireless communication without a separate PTT key operation. In addition, the flame resistance was verified by exposing the module to a flame at 950 ± 50 ℃ for 5 s and then immediately extinguishing the flame.

• The korean journal of orthodontics
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• v.37 no.3 s.122
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• pp.212-219
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• 2007

Objective: The purpose of this study was to provide an anatomical reference for cortical bone and soft tissue thickness, and the attached gingiva width in the mandible. Methods: Fifteen males and fifteen females participated in this study. An acrylic template was fabricated and the radiopaque markers were bonded on the estimated alveolar crest to take measurements of the hard and soft tissue thickness at the same locations. CT images were taken in samples wearing an acrylic template. Cortical bone and soft tissue thickness were measured at 2, 4, 6 and 8 mm from the alveolar crest in interradicular spaces from central incisor to first permanent molar. The attached gingival width was calibrated. Results: Cortical bone thickness was $1.33{\pm}0.38mm$ and soft tissue thickness was $1.49{\pm}0.54mm$. Cortical bone thickness was increased in the posterior area, while it was not the case for the soft tissue thickness. In addition, the total thickness was $2.82{\pm}0.70$. The attached gingival width was wider in the anterior area compared to that in posterior area. Conclusion: These results suggest that the attached gingiva width should be considered upon placement of mini-implants in the mandibular posterior area for orthodontic anchorage.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.267-272
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• 2016

This case report describes the treatment of two fully edentulous patients with mini-implant overdentures using different implant systems on narrow mandibular alveolar bone ridge. They were complaining about discomfort and pain wearing mandibular conventional complete dentures caused by insufficient retention. Each patient received four miniimplants in the interforaminal area of the mandible using the non-submerged flapless surgical approach. One-body type implant (Slimline, Dentium, Seoul, Korea) was used for a patient and loaded immediately after surgery. Metal housings of O-ring were attached by direct technique. For the other patient, two-piece type implant (LODI, Zest Anchors, Escondido, CA, USA) was used and impressions were made for attachment connection of the Locator's metal housings after 8 weeks of surgery. Within this case report, mandibular miniimplant overdentures using different implant systems showed improvement of patient satisfaction with favorable peri-implant tissue response 6 months after attachment connection. However, long-term follow-up is needed for further evaluation.

• Fashion & Textile Research Journal
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• v.13 no.4
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• pp.600-613
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• 2011

The purpose of this study is to provide Torso pattern for Korean middle-aged women using 3D human body scan data. 155 women in their 40's or 50's were measured by Martin's anthropometry. Merging the data of 914 middle aged women provided by Korean agency for technology and standards, total of 1,069 subjects' data were analyzed. For data analysis, ANOVA, factor analysis and cluster analysis were done using SPSS PC+. And representative subject of each cluster was selected and they participated in 3D scanning and Torso pattern suggested for middle-aged women Torso pattern which investing the amount of ease according to each group for diffuse front interscye 30%, armscye circumference 30%, back interscye 40% using 3D human body scan data. The results of this study are as follows. Firstly, as a result of the factor analysis, the first factor was 'obesity index of body', The second factor was 'verticality size of body', The third factor was 'verticality length of upper bodice', The fourth factor was 'drop value to represent silhouette', and the fifth factor was 'physique of upper bodice'. And, middle-aged women type were classified 3 types according to the cluster analysis. Type 1(Y-type) was the long upper Torso with wide shoulder. Type 2(H-type) was flat-body type with comparatively thin upper bodice and thin lower bodice. And type 3(A-type) was the obese type with comparatively thin upper bodice and fat lower bodice. Secondly, using CAD program, point filtering was performed and approximated surface model was made. It used that generated surface smoothing corrected for abnormally extruded points and scattered points based on the curvature information. And 3D surfaces were flatted onto the plane by the internal tools of CAD program. Difference ratios of outline length and area between 3D curves and 2D plane were 0.42% and 0.54%, respectively. Third, wearing test by the sensory evaluation showed that distinct difference almost every category. The movement functionality test shows that, in all the tests which reveal significant differences, especially, 'comparison pattern A' experienced inconvenience to neck width and neck depth.

• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.73-79
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• 2014

Alveolar fricative sounds /s/ and /s'/ are learned last for normal children in the speech development process for Koreans. These are especially difficult to articulate for hearing-impaired children often causing articulation errors. The acoustic phonetic evaluation uses testing tools to provide indirect and object information. These objective resources can be compared with standardized resources on speech when interpreting the results of a test. However, most previous studies in Korea did not consider acoustic studies that used the spectrum moment values of hearing-impaired children. Therefore, this study was conducted to compare the characteristics of hearing-impaired children's pronunciation of fricative sounds using spectrum moment values. For this purpose, the study selected a total of 10 hearing-impaired children (5 boys and 5 girls) currently in 3rd or 5th grade and attending one of the elementary schools in Seoul or Gyeonggi-do. For the selection process, their age, type of hearing aid, implantation of hearing aid (CI) before two years of age, hearing capacity (dB) before and after wearing the hearing aid, duration of speech rehabilitation, and time of learning alveolar fricative sounds were all considered. Also, 10 normal children (5 boys and 5 girls) were selected among 3rd or 5th grade students attending one of the elementary schools in Seoul or Gyeonggi-do. The subjects were asked to read the carrier sentence, "I say _______," including a list of 12 meaningless syllables composed of CV and VCV syllables, including alveolar fricative sounds /s/ and /s'/ and vowels /a/, /i/, and /u/. The recorded resources were processed through the Time-frequency Analysis Software Program to measure M1 (mean), M2 (variance), M3 (skewness), and M4 (kurtosis) of the fricative noise. No significant differences were found when comparing spectrum threshold values in the acoustic phonetic characteristics of hearing-impaired children and normal children in alveolar fricative sound pronunciation according to vowels /a/, /i/, and /u/, alveolar fricative sounds /s/ and /s'/, and syllable structure (CV, VCV) other than, for M3 in the comparison of groups according to disability. In the comparison of syllable structures, there were statistically significant differences in M1, M2, M3, and M4 with clinical significance. However, there was no significant difference in results when comparing the alveolar fricative sounds according to the vowels.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.3_4
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• pp.390-401
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• 2002

This study was to evaluate the fitness and the suitability of size specification of the ready made jacket for women by analysing pattern size and space between skin and clothing using 3D scanner. The results were as follows: 1. Pattern B had the lowest score and the feeling of wearing was significantly different among the given patterns even though all jacket size specification were the same. 2. Ease amount was different between each brand even though the jacket size specification was the same due to the different pattern grading rules. And increasing grading amounts were bigger in horizontal direction rather than in vertical direction. 3. We could obtain accurate a 3 dimensional figure, using 3D scanner which was very useful and more accurate than 2 dimensional data using photography method. 4. Analyzing the average space between skin and clothing of each pattern, there was no significant difference in the average space between skin and clothing among all patterns except waist part of B88 size. And analyzing the average space between skin and clothing of each measured body parts by each size, there existed a significant difference in the interscye, abdomen and hip parts.