• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.115-124
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• 2002

The purpose of this study is to analyze the ground reaction force of arm landing on arm and leg during sports aerobics. Subjects of this study were total 10 players of 5 males and 5 females who have are domain sports aerobics medalists more than the third place in national tournaments. The subjects jumped between the two ground reaction force analyzers, while landing their right hand on the front platform(#1) and their right leg on the rear platform(#2), and the data frequency was set to 200Hz. Findings of this study are as follows; More than 3 times of impact peak force of vertical reaction force acted on arm joint than on leg joint. And, when ground reaction force on foot increased, ground reaction force on hand decreased. 3 impact peaks of curve of ground reaction force were found - Impact Peak 1 incurred on the time the palm lands on the ground, Impact Peak 2 absorbing shock secondarily on wrist joint, and Active Peak incurred on the time of holding the weight while pushing out the severly bent elbow joint.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.1
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• pp.15-21
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• 2012

This paper deals with an experimental study on the reaction of muscles by functional electrical stimulation(FES) with the design and fabrication of an ankle reaction apparatus. The ankle reaction apparatus consists of a circuit part and a kinematic part, and it monitors reaction time for a particular angle of joint rotation according to FES. The experimental results showed that the change of the ankle rotation angle was linearly proportional to the change of the magnitude of FES. It also showed that the muscle's reaction time was constant no matter how large the magnitude of the stimulus. The results of this paper can be applied to develop an active-type walking-assistance robot.

• The Korean Journal of Food And Nutrition
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• v.17 no.3
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• pp.313-321
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• 2004

Separation-concentration of sulfur containing heterocyclic compounds(SCHC) from many reaction meat flavors manufactured with Maillard reaction was carried out. Profile of SCHC was identified and analyzed by GC and GC-MSD. The results were as follows. 1. Profile of SCHC could be identified 7 kinds thiazole and 11 kinds thiophene, the major produced compounds were thiophene, thiazolidine, 4-methyl-5-thiazole ethanol. 2. In the case of SCHC, relationship between changes of reaction conditions and the kind of produced components were as same, but produced amounts appeared the difference. Producing amount of complexed SCHC and caramellike note as well as oxygen containing heterocyclic compounds were high level more than high reaction temperature and long time reaction period. 3. Producing ratio of comparative simple structural SCHC were the highest level at reaction conditions of moisture content 50%, reaction temperature 100$^{\circ}C$ and reaction time 2 hours. Reaction conditions for the revelation of reaction meat flavor were below 110$^{\circ}C$ and less than 2 hours. 4. Relationship between moisture content and reaction temperature as well as reaction time had very relative relation. From the change of moisture content and reaction conditions could be obtained the simultaneously profile. Signal presentation for production of reaction meat flavor could be from extraction-separation-concentration of SCHC through simplification of raw-materials in the flavor and seasoning food industry.

• Journal of environmental and Sanitary engineering
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• v.10 no.1
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• pp.98-105
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• 1995

In the treatment of wastewater or sewage plant sludge with high solid concentration, high rate digestion process in which heating and mixing occur at a time is mainly used, and in the case of wastewater containing solid matter below 1000mg/ℓ the recently developed AF or UASB is developed Recently and commonly utilized. But these processes have weakpoints such as clogging of packing media and need of long period of trial run after microorganism granulation. In this point of view, there are active researches on the ASBR( anaerobic sequence batch reaction ) that is capable of treating of organic matter with reactor that has no packing materials and controlling the inflow time, reaction time sedimentation time and outflow time by time control without loss of microorganisms. The objectives of this study are to evaluate the efficiency of ASBR process according to the reaction time, change of treated water quality and gas output rate in the treatment of wheat plant wastewater.

• Journal of Ginseng Research
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• v.19 no.3
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• pp.249-253
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• 1995

In the browning reaction of Korean ginseng, it appears that enzymatic and non-enzymatic browning reaction occurred in the initial stage of heating fresh ginseng at low temperature, and then non-enzymatic browning reaction followed in the drying period after heating. Activation energy of the browning reaction for red ginseng was about 9.0 kcal/mol. Browning reaction of red ginseng was accede- rated with an increase in steaming time, and a great extent of browning reaction occurred between 60-90 min of steaming at 10$0^{\circ}C$. Browning pigments of red ginseng were mostly water soluble subset.

• The Journal of Korean Physical Therapy
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• v.26 no.3
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• pp.191-195
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• 2014

Purpose: The purpose of this study is to investigate whether types of sensory-stimuli cues in terms of visual, auditory, and visuoauditory cues can be affected to motor sequential learning in healthy adults, using serial reaction time task. Methods: Twenty four healthy subjects participated in this study, who were randomly allocated into three groups, in terms of visual-stimuli (VS) group, auditory-stimuli (AS) group, and visuoauditory-stimuli (VAS) group. In SRT task, eight Arabic numbers were adopted as presentational stimulus, which were composed of three different types of presentational modules, in terms of visual, auditory, and visuoauditory stimuli. On an experiment, all subjects performed total 3 sessions relevant to each stimulus module with a pause of 10 minutes for training and pre-/post-tests. At the pre- and post-tests, reaction time and accuracy were calculated. Results: In reaction time, significant differences were founded in terms of between-subjects, within-subjects, and interaction effect for group ${\times}$ repeated factor. In accuracy, no significant differences were observed in between-group and interaction effect for groups ${\times}$ repeated factor. However, a significant main effect of within-subjects was observed. In addition, a significant difference was showed in comparison of differences of changes between the pre- and post-test only in the reaction time among three groups. Conclusion: This study suggest that short-term sequential motor training on one day induced behavioral modification, such as speed and accuracy of motor response. In addition, we found that motor training using visual-stimuli cue showed better effect of motor skill acquisition, compared to auditory and visuoauditory-stimuli cues.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.459-466
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• 2017

Objective: This study examined two traffic signals with a countdown indicator in terms of driver's reaction time and subjective satisfaction score and their performance was compared with a standard traffic signal in driving simulation. Background: Dilemma zone is created when a traffic light changes at intersections. It often pushes drivers to rush in urgent and premature decision making whether to go or stop and thus induces unnecessary mental load among drivers, which may lead to sudden conflicts with following vehicles at intersections. Method: Forty college students (male: 20, female: 20) participated in this driving simulation study. Three traffic signals were employed: (1) standard traffic signal; (2) countdown-separated signal; and (3) countdown-overlaid signal. The countdown-separated and countdown-overlaid signals were designed to inform drivers of the remaining time of a green light before tuning to an amber light. Reaction times (sec) and satisfaction scores (7-point scale) for the two signals with a countdown indicator were compared with those for the standard traffic signal. Results: Reaction times of the countdown-separated (0.49 sec) and countdown-overlaid (0.43 sec) signals were significantly shorter than that of the standard signal (0.67 sec). Satisfaction scores of the countdown-separated (5.3 point) and countdown-overlaid (5.6 point) signals were greater than that of the standard signal (3.8 point). Lastly, the countdown-overlaid signal showed better performance than the countdown-separated signal, but their differences in reaction time (0.06 sec) and satisfaction score (0.3 point) were small. Conclusion: Traffic signals with a countdown indicator can improve drivers' reaction time and satisfaction score than the standard traffic signal. Application: Traffic signals with a countdown indicator will be useful for reducing the length of dilemma zone at intersections, by allowing drivers to predict the remaining time of a green light.

• Anxiety and mood
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• v.4 no.2
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• pp.99-103
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• 2008

Objectives : The authors sought to examine the differences in the number of P300 detected by subjects in experimental and control groups when exposed to relevant stimuli. In addition, the authors tried to determinethe subjects' reaction time when asked to respond to relevant stimuli. Methods : The subjects were 20 informed female volunteers aged 22-38 years (median age : 24). Relevant stimuli (concealed information) were created by unknowingly exposing the two groups to obscene pictures and semantic questions. The number of P300 detected and the length of reaction time were compared between the two groups. Results : Contrary to theauthors' expectations, there were no significant differences in the number of P300 detected or in the length of reaction time between the two groups. Conclusions : These results indicate that, unlike a polygraph test, concealed information tests adopting P300 and reaction time as major physiological responses ofsubjects exposed to meaningful personal information might not serve as a valid practical tool in the field of criminal psychology. However, further studies involving a greater number of subjects are needed before a final conclusion regarding the validity of this new type of concealed information test can be drawn.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.577-584
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• 1997

Validation and Standardization of neurobehavioral instrument in Korean occupational setting has not been studied ever. This study tried to validate the newly developed computerized psychomotor tests, Neurobehavioral Tests for Occupational Screening (NTOS). Male patients with Parkinson's disease(n=12) and male workers who never exposed to occupational neurotoxic materials and didn't have neurologic disease(n=21), performed some tests from NTOS; simple reaction time, choice reaction time(2 choice), and finger tapping(both hands). In simple analysis, difference between patient group and worker group was significantly great. Adjusted for age and education years, simple reaction time and finger tapping(both hand) were statistically significantly different between two groups(p<.05). Choice reaction time was also different(p<.1) but error frequency of choice reaction time test was not. Generally, this results showed NTOS could detect impairment of psychomotor function. But insensitive results of choice reaction time was partly due to small sample size and confounding variables and so required future study and refinement at improvement of NTOS.

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.191-202
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• 2004

The batting performance in baseball is a repetitive movement. In order to make the stabilization of posture and the efficient shift of body weight, both the range of stance and stride are important. The previous studies explained that the consistent stride which included the amount of time, stance, and direction were needed. However, the batting performance is frequently changed according to the several speed of ball. Therefore, this study was to analyze the reaction time, the range of stance, the change of stride, and the change of GRF during the batting movement in three kinds of ball speed (120km/h, 130km/h, & 140km/h). Seven elite players are participated in this study. 1. The reaction time of the stride phase was short whereas the time of the swing phase was long according to the increasing ball speed. 2. The range of the stance was wide and the mediolateral direction of the stride was decreased according to the increasing ball speed. 3. In the three kinds of ball speed, the change of body weight was transferred to the center, the rear foot, and the front foot directions. The ball speed of 130km/h showed the high frequency of the suitable batting. At this ball speed, the movement of the body weight was shifted smoothly and the value of the Ground Reaction Force was large enough.