• Korean Journal of Applied Biomechanics
• /
• v.16 no.3
• /
• pp.137-148
• /
• 2006

The purpose of this study was to compare muscle activity in the lower extremity during walking wearing jogging and roller shoes. Twelve male middle school students (age: 15.0 yrs, height 173.7 cm, weight 587.7 N) who have no known musculoskeletal disorders were recruited as the subjects. Seven pairs of surface electrodes (QEMG8, Laxtha Korea, gain = 1,000, input impedance >$1012{\Omega}$, CMMR >100 dB) were attached to the right-hand side of the body to monitor the rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and medial (GM) and lateral gastrocnemius (GL) while subjects walked wearing roller and jogging shoes in random order at a speed of 1.1 m/s. An event sync unit with a bright LED light was used to synchronize the video and EMG recordings. EMG data were filtered using a 10 Hz to 350 Hz Butterworth band-passdigital filter and further normalized to the respective maximum voluntary isometric contraction EMG levels. For each trial being analyzed, five critical instants and four phases were identified from the recording. Averaged IEMG and peak IEMG were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p<.05). The VM, TA, BF, and GM activities during the initial double limb stance and the initial single limb stance reduced significantly when going from jogging shoe to roller shoe condition. The decrease in EMG levels in those muscles indicated that the subjects locked the ankle and knee joints in an awkward fashion to compensate for the imbalance. Muscle activity in the GM for the roller shoe condition was significantly greater than the corresponding value for the jogging shoe condition during the terminal double limb stance and the terminal single limb stance. Because the subjects tried to keep their upper body weight in front of the hip to prevent falling backward, the GM activity for the roller shoe condition increased. It seems that there are differences in muscle activity between roller shoe and jogging shoe conditions. The differences in EMG pattern may be caused primarily by the altered position of ankle, knee, and center of mass throughout the walking cycle. Future studies should examine joint kinematics during walking with roller shoes.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.3
• /
• pp.105-115
• /
• 2006

The purpose of this study is to elucidate the mechanical characteristics of lower extremity joint movements at different walking speeds in obese people and suggest the very suitable exercise for obese person's own body weight and basic data for clinical application leading to medical treatment of obesity. This experimental subjects are all males between the ages of 20 and 30, who are classified into two groups according to Body Mass Index(BMI): one group is 15 people with normal body weight and the other 15 obese people. Walking speed is analysed at 3 different speeds ($1.5^m/s$, $1.8^m/s$, $2.1^m/s$) which is increased by $0.3^m/s$ from the standard speed of $1.5^m/s$. We calculated joint moments of lower extremity during stance phase through video recording and platform force measurement.Two-way ANOVA(Analysis of Variance, Mix) is applied to get the difference of moments according to walking speeds between normal and obese groups. Pearson's Correlation Analysis is applied to look into correlation between walking speeds and joint moments in both groups. Significance level of each experiment is set as ${\alpha}=.05$. As walking speed increases maximum ankle plantar flexion moment in the stance phase is smaller in obese group than in normal group, which is suggestive of weak toe push-off during terminal stance in obese group, and the highest maximum ankle plantar flexion moment in obese group during the middle speed walking($1.8^m/s.$). Maximum ankle dorsal flexion moment in obese group is relatively higher than in normal group and this is regarded as a kind of compensatory mechanism to decrease the impact on ankle when heel contacts the floor. Maximum knee flexion and extension moments are both higher in normal group with an increase tendency proportional to walking speed and maximum hip flexion and extension moments higher in obese group. In summary, maximum ankle plantar flexion moment between groups(p<.025), maximum knee moment not in flexion but in extension(p<.001) within each group according to increasing walking speed, and maximum hip flexion and extension moment(p<.001 and p<.004, respectively according to increasing walking speed are statistically significant but knee and hip moments between groups are not. Pearson correlation are different: high correlation coefficients in maximum knee flexion and extension moments, in maximum hip extension moment but not hip flexion, and in maximum ankle dorsal flexion moment but not ankle plantar flexion, in each group. We suspect that equilibrium imbalance develops when the subject increases walking speed and the time is around which he takes his foot off the floor.

• Journal of the Korean earth science society
• /
• v.27 no.5
• /
• pp.509-520
• /
• 2006

The purpose of this study was to analyze laboratory instructions in a secondary school science with an analysis instrument on science laboratory instruction. For its purpose, we used an instrument that analyzes three dimensions of the secondary laboratory instructions. This analysis instrument was composed of 3 categories (the aim of the laboratory activity, interaction, and inquiry process) which are spread into 20 sub-categories, and its validity was checked by four science educators with factor of 0.89. For its purpose, 21 sessions of lab instructions were video-recorded and transcribed. According to the results, in the aims category, the instructions mainly focused on two aims; acquiring the declarative knowledge and increasing attitudes toward science. In the interaction category, some of the observations made were that the teachers's questions could not gather the students' divergent thinking, their directive instructions were centered around themselves rather than giving opportunities for students to be centered within laboratory activities, and students' interaction were rarely shown. Therefore, interaction was classified as level I. In the inquiry process, presenting phenomenon or questionings about the subjects were little observed, and students' hypothesizing and predicting were almost nonexistent. Most of the activity designs within lab session were given from the teachers' directions or worksheets, and students solely focused on data collecting and recording. Hence, inquiry process were classified level I.

• Journal of The Korean Association For Science Education
• /
• v.36 no.6
• /
• pp.947-957
• /
• 2016

Today, in accordance with emphasizing the importance of character education, science educators have tried to implement character education in the field of science education. Therefore, this research aims to confirm the possibility of the realization of 'Practice Centered Mechanism of Manifesting Character' developed on the basis of character education theory through the application of the NABI Program based on Nature-Study. For this, the NABI program was applied to 24 3rd grade students of an elementary school for a period of ten months. Qualitative data was collected like students' reports, journals, and video recording of the classes. This data was classified into 'value, judgment, action,' the steps of 'Practice Centered Mechanism of Manifesting Character,' and text was written by interpreting the data. The research resulted in the following: First, students formed 'value' by making a connection with the objects. And the various values - individual, interpersonal, social, ecological, and spiritual - are formed according to the type of objects with which the students felt a connection to. Second, students need to judge the problems of the real world at the 'judgment' step. Third, at the 'action' step, students practice moral behavior in relation to the sympathy or feeling they felt with the objects that they made a connection to. In conclusion, 'Practice Centered Mechanism of Manifesting Character' can be realized through the application of the NABI Program. The NABI Program can be a definite way to implement character education in the field of science education.

• The KIPS Transactions:PartC
• /
• v.11C no.6 s.95
• /
• pp.731-738
• /
• 2004

With the increase of digital content usages, the protection for digital content and intellectual property becomes more important. The DRM(digital rights management) technologies are applicable to protect not only any kind of digital contents but also intellectual property. Besides such techniques are required for recorded digital broadcasting contents due to introduction of digital broadcasting techniques and storage devices such as personal video recorder. The conventional protection scheme for broadcasting content is the CAS(conditional access system) by which the access of viewer is controlled on the specific channels or programs. The CAS prohibits the viewer from delivering the digital broadcasting content to other person, so it results in restriction of superdistribution on the digital broadcasting content. In this paper, for broadcast targeting unspecfic many people, we will design the service model of the protection and distribution of digital broadcasting content using encryption and license by employing the concept of DRM. The results of implementation are also shown to verify some functions of each component. An implemented system of this paper has some advantages that the recording of broadcast content is allowed on set-top-box and superdistribution is available by consumer. Hence it provides content providers and consumers with trustworthy environment for content protection and distribution.

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.3
• /
• pp.445-453
• /
• 2012

The aim of this paper was to prove that if the risk level in combined tasks was improved through evaluation of postural load of liquid weight measurement process, the workload level and ratio of exposure time would be changed, and the time of process would be seen concurrently. Background: According to results of epidemiological studies conducted by Korea Occupational Safety & Health Agency, 122 musculoskeletal disorders occurred during 1992 to 2008, in which manufacturing industry covers 96(78.7%) of total. However, this is an insufficient level and only occupies 39% based on the South Korea's manufacturing standard industrial classification(246 industries). Method: Firstly, the number of batches weighed on one day(460min) was investigated based on the work performed and Weight measured weekly. VCR recording was taken based on the level of liquid ingredients prescribed for 1batch using the Camcorder. After dividing a 356 sec video into 1 sec using the screen capture function in Gom player, the job classification was performed by analyzing the change of working postures, which revealed 148 working postures. Time measurement was decided by time of the postures was being maintained. Then, the REBA analysis was performed for the working postures. The ratio of Exposure time was calculated based on the measurement time and REBA Score. In addition, the recommendations were designed and implementation was carried out for the working postures with REBA Score higher than 3. Finally, after the intervention, REBA measurement, time measurement, and ratio of exposure time were calculated for the comparison of works before and after improvement. Results: The number of work elements was decreased by 30.4% from 148 to 103 after improvement. The results of time measurement showed that the time was reduced by 46.3% from 356 sec to 191 sec. And the ratio of exposure time was also improved by 52.1% from 0% to 52.1% after improvement. Conclusion: The reduction of time was found to improve the productivity of management. Furthermore, because the reduction of ratio of exposure time and the improvement of workload level are the improvement of discomfort, it would contribute to the improvement of the worker's psychological working posture. Application: These results would contribute to musculoskeletal disease prevention and management performance. Further studies for other industries would be needed based on this case study.

• Journal of the Korean Chemical Society
• /
• v.45 no.5
• /
• pp.470-480
• /
• 2001

The purpose of this study was to investigate the effects of science inquiry experiments emphasizing social interaction on the development of process skills of the students. The social interactions by cognitive level of the students were also analyzed. For this study, 197 8th grade students were sampled. They were divided into an experimental group and a control group. During four-month period, the experimental group received science inquiry experiments treatment emphasizing social interactions while the control group received traditional treatment. Not only science inquiry ability pretest-posttest, but also multiple data collection method such as a questionnaire, class observation, and audio/video recording were used in collecting the data. According to the results of this study, it was found that the mean score of the experimental group was significantly higher than that of the control group at 0.05 level. It was also found that the students of high cognitive level led the peers and participated in the class discussion actively with the teacher while the students of low cognitive level followed the students of high cognitive level and showed inactive interaction with the teacher. Analysis of the students' perceptions on inquiry experiments showed that students participated in discussion actively in the class as these experiments gave an opportunity for them to discuss and were able to solve the problems with peers' help through discussion.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.28 no.2
• /
• pp.89-95
• /
• 2017

Background and Objectives : High-speed videolaryngoscopy (HSV) is the only technique that captures the true intra-cycle vibratory behavior of the vocal folds by capturing full images of the vocal folds. However, it has problems of no immediate feedback during examination, considerable waiting time for digital kymography (DKG), recording duration limited to a few seconds, and extreme demands for storage space. Herein, we demonstrate a new post-processing method that converts HSV images to two-dimensional digital kymography (2D-DKG) images, which adopts the algorithm of 2D videokymography (2D VKG). Materials and Methods : HSV system was used to capture images of vocal folds. HSV images were post-processed in Kay image-process software (KIPS), and conventional DKG images were retrieved. Custom-made post-processing system was used to convert HSV images to 2D-DKG images. The quantitative parameters of the post-processed 2D-DKG images was validated by comparing these parameters with those of the DKG images. Results : Serial HSV images for all phases of vocal fold vibratory movement are included. The images were converted by the scanning method using U-medical image-process software. Similar to conventional DKG, post-processed 2D DKG image from the HSV image can provide quantitative information on vocal fold mucosa vibration, including the various vibratory phases. Differences in amplitude symmetry index, phase symmetry index, open quotient, and close quotient between 2D-DKG and DKG were analyzed. There were no statistical differences between the quantitative parameters of vocal fold vibratory movement in 2D-DKG and DKG. Conclusion : The post-processing method of converting HSV images to 2D DKG images could provide clinical information and storage economy.

• Journal of Korean Society of Transportation
• /
• v.31 no.3
• /
• pp.19-32
• /
• 2013

The study aims to find the characteristics of children's crossing behavior on crosswalk in school zones. It considers accident occurrence and physical form of school zones. Seven elementary school zones were investigated. Using data collected by field observation and video recording, statistical analysis, CHAID algorithm analysis, and pattern analysis were performed. As a result, it was found that children's waiting, attention and distraction were related to the accident occurrence. While 69.1% children showed waiting-before-crossing behavior in low-accident occurrence crosswalk, 83.6% children showed non waiting-before-crossing behavior in high-accident occurrence crosswalk. Moreover, the ratio of waiting, attention behavior was found to be higher when the width of the crosswalk was wide and the distance from the school's entrance to the crosswalk was long. These research findings showed that children's behavior-oriented approach was required to improve safety in school zone.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.1
• /
• pp.101-108
• /
• 2006

The purpose of this study was to compare GRF characteristics during walking wearing jogging and roller shoes. Twelve male middle school students (age: $15.0{\pm}0.0\;yrs$, height: $173.6{\pm}5.0\;cm$, weight: $587.6{\pm}89.3\;N$) who have no known musculoskeletal disorders were recruited as the subjects. Kinematic data from six S-VHS camcorders(Panasonic AG456, 60 fields/s) and GRF data from two force platform; (AMII OR6-5) were collected while subjects walked wearing roller and jogging shoes in random order at a speed of 1.1 m/s. An event sync unit with a bright LED light was used to synchronize the video and GRF recordings. GRF data were filtered using a 20 Hz low pass Butterworth. digital filter and further normalized to the subject's body weight. For each trial being analyzed, five critical instants and four phases were identified from the recording. Temporal parameters, GRFs, displacement of center of pressure (DCP), and loading and decay rates were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p <.05). Vertical GRFs at heel contact increased and braking forces at the end of initial double limb stance reduced significantly when going from jogging shoe to roller shoe condition. Robbins and Waked (1997) reported that balance and vertical GRF are closely related It seems that the ankle and knee joints are locked in an awkward fashion at the heel contact to compensate for the imbalance. The DCP in the antero-posterior direction for the roller shoe condition was significantly less than the corresponding value for the jogging shoe condition. Because the subjects tried to keep their upper body weight in front of the hip to prevent falling backward, the DCP for the roller shoe condition was restricted The results indicate that walking with roller shoes had little effect on temporal parameters, and loading and decay rates. It seems that there are differences in GRF characteristics between roller shoe and jogging shoe conditions. The differences in GRF pattern may be caused primarily by the altered position of ankle, knee, and center of mass throughout the walking cycle. Future studies should examine muscle activation patterns and joint kinematics during walking with roller shoes.