• The Journal of Korean Physical Therapy
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• v.21 no.3
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• pp.61-68
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• 2009

Purpose: The purpose of this study was to analyze the changes of the relative impulse of the foot when carrying 5 types of schoolbag during level walking. Methods: Forty-four normal subjects were divided into 5 groups according to the method of carrying a bag: carrying no bag (condition 1), a backpack (condition 2), a shoulder bag (condition 3), a cross bag (condition 4) and a one-hand bag (condition 5). To evaluate the partial relative impulse, 7 areas were measured on the sole of a foot: the hallux, toe, 1st metatarsal head (Met1) and the 2nd & 3rd metatarsal heads (Met2/3), the 4th & 5th metatarsal heads (Met4/5), mid foot and heel. Repeated one-way analysis of variance (ANOVA) and independent t-tests were used to analyze the statistical data. Results: In the right foot, the relative impulses in every areas revealed no significant difference (p>0.05), however, the relative impulses at Met1, Met2/3, Met4/5 and heel were significantly different between the different conditions (p<0.05). There were significant differences on comparing the relative impulse between left and right foot within one condition, the mid foot in condition 2, as well as the hallux and Met1 in condition 3 (p<0.05). In condition 4, the toe, Met1, Met4/5 and mid foot were significantly different (p<0.05). The values at the hallux, toe and Met1 in condition 5 also were significantly different (p<0.05). Conclusion: These findings showed that the symmetrical relative impulse of the foot was present in the case of carrying a backpack, but there was an extra load on specific regions and asymmetrical relative impulses in the case of carrying a shoulder bag, a across bag and a one-hand bag. (ED note: this abstract is not clear. You need to work on it.)

• Korean Journal of Human Ecology
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• v.13 no.1
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• pp.135-144
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• 2004

The purpose of this study was to investigate the wearing sensation and satisfaction of high school girls winter uniform' jacket. The subject participated in the study were 599 high school girls attending four different schools. The fabrics were divided into two parts of stretch and non-stretch woven fabrics. The results were as follows: 1. The high school girls showed body image distortion that she recognized herself as fatter than her real body type. Especially, this was severe in the slim body type. 2. In the aspect of the satisfaction for uniforms' jacket made with stretch fabric and non-stretch woven fabric. the elastic fabric was more satisfied than the non-stretch one because its width and length was shorter and fitter than non-stretch one. 3. When they wore the school uniform jacket, the wearing sensation of one made with stretch and non-stretch woven fabrics showed significant differences in arms hole when raising hands, front bust when carrying backpack on their back, backs while studying at desks, the upper arms and the elbows. 4. As for the alteration of school uniform jacket, the non-stretch woven fabric was appeared to be altered more than the stretch one.

• Child Health Nursing Research
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• v.21 no.4
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• pp.320-330
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• 2015

Purpose: The purpose of this study was to investigate the use of schoolbags and the prevalence of musculoskeletal symptoms among elementary school children and to identify factors associated with relative schoolbag weight and musculoskeletal symptoms. Methods: A descriptive correlation study was conducted with 228 elementary school children in grades 4-6. A self-administered questionnaire was used for data collection. Descriptive statistics, t-test, ANOVA, $x^2$-test or Fisher's exact test, logistic regression analysis were used for data analysis. Results: Mean relative schoolbag weight (RSW) was 6.40%. Among participants, 13.2% carried more than 10% of their RSW. Only 49.6% of participants organized the contents in their school backpack correctly. Musculoskeletal symptoms were reported by 42.5% of participants. Results from logistic regression analysis identified grade was a significant factor predicting RSW, and gender, RSW, and using a locker were significant factors predicting musculoskeletal symptoms among schoolchildren. Conclusion: Although RSW of school children in this study was within the currently recommended load limit, a considerable proportion of school children were not following guidelines for safe schoolbag use. An effective schoolbag safety campaign for parents, students, and teachers needs to be developed and evaluated to prevent possible musculoskeletal symptoms related to schoolbag use.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.245-256
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• 2021

This study was conducted to identify the applicability of a LiDAR sensor to forest resources inventories by comparing data on a tree's position, height, and DBH obtained by the sensor with those by existing forest inventory methods, for the tree species of Criptomeria japonica in Jeolmul forest in Jeju, South Korea. To this end, a backpack personal LiDAR (Greenvalley International, Model D50) was employed. To facilitate the process of the data collection, patterns of collecting the data by the sensor were divided into seven ones, considering the density of sample plots and the work efficiency. Then, the accuracy of estimating the variables of each tree was assessed. The amount of time spent on acquiring and processing the data by each method was compared to evaluate the efficiency. The findings showed that the rate of detecting standing trees by the LiDAR was 100%. Also, the high statistical accuracy was observed in both Pattern 5 (DBH: RMSE 1.07 cm, Bias -0.79 cm, Height: RMSE 0.95 m, Bias -3.2 m), and Pattern 7 (DBH: RMSE 1.18 cm, Bias -0.82 cm, Height: RMSE 1.13 m, Bias -2.62 m), compared to the results drawn in the typical inventory manner. Concerning the time issue, 115 to 135 minutes per 1ha were taken to process the data by utilizing the LiDAR, while 375 to 1,115 spent in the existing way, proving the higher efficiency of the device. It can thus be concluded that using a backpack personal LiDAR helps increase efficiency in conducting a forest resources inventory in an planted coniferous forest with understory vegetation, implying a need for further research in a variety of forests.

• Journal of Korea Multimedia Society
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• v.21 no.3
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• pp.415-422
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• 2018

Advances of telecommunication technology bring various changes in journalism field. Reporters started to gather, edit, and transmit content to main server in media company using hand-held smart media and notebook computer. This paper tried to testify valid bit-rate of visual news content using LTE network and mobile phone. Field news like natural disasters need real-time transmission of video content. But broadcasting company normally use heavy ENG system and transmission satellite trucks. We prepared and experimented different types of visual content that has different bit-rates. Transmission tool was LU-60HD mobile system of LiveU Corporation. Transmission result shows that bit-rate of 2Mbps news content is not suitable for broadcasting and VBR (Variable Bit Rate) transmission has better definition quality than CBR (Constant Bit Rate) method. Three different bit-rate of VBR transmission result shows that 5Mbps clip has better quality than 1Mbps and 3Mbps. The higher bit-rate, the better video quality. But if the content has much movements, that cause delay and abnormal quality of video. So optimizing the balance between stability of signal and quality of bit-rate is crucial factor of real-time broadcasting news gathering business.

• Journal of Korean Physical Therapy Science
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• v.18 no.2
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• pp.29-40
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• 2011

Purpose: The purpose of this study was to analyze the changes of parameters of foot contact by various carrying a pack methods during walking. Method: The subjects were consisted of normal forty four persons (males 30, females 14, mean age 23). The carrying a pack methods were classified into five conditions: carrying no bag(Con 1), carrying a backpack(Con 2), carrying a shoulder bag(Con 3), carrying a cross bag(Con 4), carrying a one-hand bag(Con 5). All subjects were participated in these five condition and measured foot pressure by F-scan system during walking. Then foot contact time, foot contact area, foot contact length and width were measured and analyzed. The repeated one-way analysis of variance (ANOVA) was used to get difference between conditions and independent t-test was used to get difference between left and right foot within condition. Result: In the comparison of parameters of foot, contact time, contact area and mid foot width were significantly different between conditions(p<.05), and in both foot contact time at condition 5 showed the most significant reduction(p<.05). In the comparison of parameters of foot between left and right foot within condition, every conditions were not significantly different(p>.05). Conclusion: In this study various carrying methods changed the parameters of foot contact and showed significant difference in some articles between carrying methods. However, asymmetric load of pack by carrying methods didn't affected symmetry of parameters of foot contact between left and right foot.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.5
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• pp.739-753
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• 2012

Based on 'Backpack-free day' and 'Unsupervised studying day' in the early 1980s, 10% of all schools in 2004 had at least 1 day of five-day classes a month as at least 2 days were enforced in 2006, and most elementary and middle schools had widely enforced the five-day class since 2012 March. The five-day class system expands the stage of studying from school to families and local societies to build an educational community related to school-family-local societies to provide various activities such as culture, art, sports, social, nature experiences on holidays to have the goal to foster creative future talents with proper personality understanding and considering others. In Busan, the five-day week class of Saturday program is being operated in various methods by national local government and public organizations. The Saturday program of local societies registered in the Saturday school of the information sharing networks are 2823 in total for the past 6 years which are being operated by national local government and public organizations. However, participation of students in the Saturday program is around 20% in 2012 March when Saturday holiday system was widely conducted. For this, problems in the Saturday programs that are currently being enforced are to be closely analyzed and participation expansion plans are to be made. Therefore, this study analyzes and investigates operation forms of Saturday programs conducted in Busan to propose an improvement plan to fulfill goals of Saturday programs and boost participation of students.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.1
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• pp.15-24
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• 2010

Purpose : The purpose of this study was to investigate the effect of loading position on plantar center of pressure(COP) displacement when carrying a schoolbag during walking. Methods : Forty-four normal subjects were randomly assigned to five groups according to the method of carrying a schoolbag. The carrying a schoolbag methods were classified into five conditions: no bag (condition 1), a backpack (condition 2), a shoulder bag (condition 3), a cross bag (condition 4), a one-hand bag (condition 5). COP displacement such as anteroposterior distance and mediolateral distance of COP were measured with F-scan system. The repeated one-way analysis of variance (ANOVA) and independent t-test were used to confirm the statistical significance. Results : In the comparison of parameters of COP displacement between conditions, anteroposterior distance and mediolateral distance in the left foot and mediolateral distance in the right foot were not significantly different(p>.05), but anteroposterior diatance in the right foot was significantly different(p>.05). Between left and right foot, at condition 1 and 5 the mediolateral distance of COP was significantly different(p<.05) but anteroposterior distance at condition 1 and 5, anteroposterior distance and mediolateral distance of COP at condition 2, 3 and 4 were not significantly different(p>.05). Conclusion : These findings showed that the various loading position by five types of carrying a schoolbag didn't have influence significantly on COP displacement on during walking because of mechanism of postural adaption.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.101-110
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• 2009

The unconscious and non-intrusive measurements of activity signals or physiological signals represent important enabling technologies for realizing a ubiquitous healthcare environment as well as a related UI. Particularly, non-intrusive measurements should be used in activity monitoring system for long-term monitoring. This paper is based on activity estimation by measuring the activity signals of a user using a handhold device with an accelerometer. The user activity estimation system (UAES) presented in this paper makes non-intrusive measurements of activity signals to minimize inconveniencing a user and to create a more practical implementation in real life. Thus, a variety of positions in which the handhold device can be carried by a user for daily use is considered, such as in the front/hip/shirt pockets, a backpack, on the waist, and in the hand.

• Journal of agriculture & life science
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• v.43 no.4
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• pp.21-31
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• 2009

Dipterans are excellent insects to serve as forensic indicators to determine the postmortem interval of a human corpse. Therefore, we undertook a study to identify the major dipterans that are attracted to and develop in vertebrate carcasses. To determine what dipterans occur in Korea, chicken carcasses were placed in various habitats including the forest, open field, stream bank, greenhouse, rooftop, rice paddy, Chinese cabbage field, vacant hut, and pond at different times of the year. The dipterans were collected at various time intervals after placement in each habitat until the end of decomposition and identified. Our results showed that 49 identified and unidentified dipteran species from 36 genera in 19 families were collected from the carcasses. Habitat placement influenced the number of species isolated from the carcasses. For example, 39 species were collected from the forest habitat, 28 species from the open field, stream bank, or greenhouse each, 16 species from a vacant home, and 12 species from the pond. The dipteran species that were collected from all habitats were Phaenicia sericata, Lucilia illustris, and Lucilia sp. in the family Calliphoridae and Boettcherisca peregrine in the family Sarcophagidae. Other dipteran species that were isolated depended on carcass placement that is, fewer dipteran species were observed from carcasses in the backpack and much more species were recorded from unburied carcasses than buried carcasses. P. sericata, L. illustris, Lucilia sp., B peregrine and an unidentified sarcophagid species were observed year round, but some dipterans showed seasonal differences.