• Journal of Mechanical Science and Technology
• /
• v.19 no.5
• /
• pp.1123-1130
• /
• 2005

In view of the lack of efficient coordination of interdependent task in the collaborative design system, the mechanisms for temporal and resource coordination problems are established based on Petri Nets, respectively. Both of the mechanisms are encapsulated and implemented in the coordination component so as to increase the flexibility and acceptability of the system. We model the CSCW system based on Petri Nets for simulation, analysis and optimization. A case study on the overhead traveling crane is given to demonstrate and validate our theory.

• Journal of Biomedical Engineering Research
• /
• v.28 no.3
• /
• pp.417-422
• /
• 2007

In this study, we investigated spatio-temporal eye-hand coordination by the "Global effect paradigm", a target-distracter configuration Global effect is observed a variety of visual tasks, for example, during rapid automatic tracking, scanning for target detail, and the comparison of target configurations. Global effect used to investigate eye-hand coordination with a task that presents a target close to a distracter. Eight young subjects participated in the experiments. The experiments consist of using a distracter less eccentric than the targe1 and using a distracter more eccentric than target. Each experiment consist of tasks which are making reference, pointing the target with watching visual stimulation(saccade) and pointing the target. The subject's task was to move towards the target as quickly as possible. We measured the eye movement by using EOG and the hand movement by using NDI Optotrak system. This study shows that eye and hand movement exists for global effect paradigm in spatio-temporal coordination.

• Korean Journal of Applied Biomechanics
• /
• v.19 no.3
• /
• pp.593-601
• /
• 2009

The goal of this study was to investigate the lower extremity's coordination determined by temporal relations with increasing high-heel (3, 7, 9cm) while walking on a treadmill. Twelve healthy women who walked on a treadmill under three conditionswearing 3cm high-heel shoes, 7cm, and 9cm-while kinematic data were collected using a six-cameras (240Hz) Qualisys ProReflex System. From these data, knee flexion, tibia internal rotation, and foot eversion were calculated in Euler technique and found the time for occurring the maximum angle of these movements. The maximum angle of these movements occurred almost simultaneously in 3cm high-heel walking, but not in 7cm and 9cm. The ratio of time for maximum angle of the foot eversion to tibia internal rotation converged to 1 in 3cm high-heel walking, but were less than 1 in 7cm and 9cm. In conclusion, it was indicated that 3cm high-heel walking had better the lower extremity's coordination compared with 7, 9cm high-heel walking.

• Korean Journal of Applied Biomechanics
• /
• v.28 no.2
• /
• pp.109-117
• /
• 2018

Objective: To compare head and hand movement patterns during squash forehand motions between experts and less-skilled squash players. Method: Four experts and four less-skilled squash players participated in this study. They performed squash forehand swings and a VICON motion analysis system was used to obtain displacement and velocity data of the head and right hand during the movement. Mann-Whitney U-tests were performed to compare head and hand range of motion and peak velocity, and cross-correlation was performed to analyze the head-hand coordination pattern between groups in three movement directions. Results: In terms of head and hand kinematic data, experts had greater head range of motion during down swings than less-skilled squash players. Experts seemed to reach peak hand velocity at impact by reaching peak head velocity followed by hand peak velocity within a given temporal sequence. In terms of head-hand coordination patterns, both groups revealed high positive correlations in the medial-lateral direction, indicating a dominant allocentric coordination pattern. However, experts had uncoupled coordination patterns in the vertical direction and less-skilled squash players had high positive correlations. These results indicate that the head-hand movement pattern likely an important factor squash forehand movement. Conclusion: Analysis of head and hand movement patterns could be a key variable in squash training to reach expert-level performance.

• The Journal of Korean Academy of Prosthodontics
• /
• v.25 no.1
• /
• pp.213-226
• /
• 1987

The purpose of this study was to standardize and classify the coordination pattern among the left and right masseter and anterior temporal muscles, in terms of integrated EMG values per stroke during gum chewing in normal subjects. In this study, 20 normal subjects were selected to chew a piece of gum and integrated EMG from middle portion of the masseter and anterior temporal muscles on both sides were recorded 20 times during each of the right and left chewing respectively. And the Bioelectric Processor Model EM2 (Myo-tronies Research, Inc., U.S.A.) with the surface electrodes was used to record the EMG activity during all experimental procedures. The results were as follows; 1. In all subjects, the chewing side masseter muscle was predominantly active among the four muscles examined. 2. The integrated EMG value of the middle of masseter muscle was significantly predominant than those of the anterior temporal muscle (p<0.0001) on the chewing side, but no significant predominant was observed on the nonchewing side (p<0.98). 3. In comparison with same muscles on the chewing and nonchewing side, low correlation coefficient was found between the middle of masseter muscles (R=0.317), but high correlation coefficient was found between the anterior temporal muscles (R=0.738). Between two muscles on the same side, there were significant correlation in the chewing (R=0.557) and nonchewing side (R=0.625). 4. In the coordination patterns among four muscles examined, distinct individual differences were found, but in an identical subject one fixed pattern appeared with significant reproducibility.

• Journal of Oral Medicine and Pain
• /
• v.13 no.1
• /
• pp.23-33
• /
• 1988

The purpose of this study was to standardized and classify the coordination pattern among the chewing side and non-chewing side masseter and anterior muscles, in terms of EMG values on lateral excursion, clenching, and mastication in presence of the non-chewing side. In this study, 25 subjects were selected for experiment of lateral excursion, clenching and mastication and EMG value of the masseter and anterior temporal muscle on both sides were recored 2 times respectively. The bioelectric processor model EM2(Myo-tonic research, INC. U.S.A.) with the surface electrodes were used to record the EMG activity during all experimental procedures. The results were as follows : 1. During lateral excursion on intereference of non-chewing side, the EMG values of the temporal muscle were significantly more prominent than those of the temporal muscle on the non-chewing side. The EMG values of non-chewing side were significantly more prominent than those of chewing side on the both side masseter muscle and those of chewing side were significantly more prominent than those of non-chewing side on the both side temporal muscle. 2. During clenching on the occlusal interferance, the EMG values of non-chewing side masseter muscle were most prominent. 3. During mastication on the occlusal interferance, the EMG values of the chewing side temporal muscle were most prominent and those of non-chewing side temporal muscle were the lowest. 4. The EMG values of temporal muscle of non-chewing side on interferance were significantly more prominent than those of canine guidance during lateral excursion. 5. During clenching on the occlusal interferance, the EMG values of the masseter and the temporal muscles of the non-chewing side were significantly more prominent than canine guidance, but those of chewing side temporal muscle on canine guidance were significantly more prominent than those of interferance. 6. During mastication on canine guidance, the EMG Values of the temporal muscle on the chewing side, the masseter muscle on the chewing side and the temporal muscle on the non-chewing side were more prominent than those of interferance, but temporal muscle of non-chewing side was not different between canine guidance and occlusal interferance on non-chewing side.

• Phonetics and Speech Sciences
• /
• v.3 no.3
• /
• pp.27-33
• /
• 2011

This paper explores two articulatory characteristics of inter-consonantal coordination observed in lingual-lingual (/kt/, /ks/) and labial-lingual (/pt/) sequences. Using electromagnetic articulometry (EMMA), temporal aspects of the lip movement and lingual movement (of the tongue tip and the tongue dorsum) were examined. Three sequences (/ks/, /kt/, /pt/) were investigated in two respects: gestural overlap in C1C2 and formation duration of coronals in C2 (/t/ or /s/). Results are summarized as follows. First, in a sequence of two stop consonants gestural overlap did not vary with order contrast or a low-level motor constraint on lingual articulators. Gestural overlap between two stop consonants was similar in both /kt/ (lingual-lingual; back-to-front) and /pt/ (labial-lingual; front-to-back). Second, gestural overlap was not simply constrained by place of articulation. Two coronals (/s/ and /t/) shared the same articulator, the tongue tip, but they showed a distinctive gestural overlap pattern with respect to /k/ in C1 (/ks/ (less overlap) < /kt/ (more overlap)). Third, temporal duration of the tongue tip gesture varied as a function of manner of articulation of the target segment in C2 (/ks/ (shorter) < /kt/ (longer)) as well as a function of place of articulation of the segmental context in C1 (/pt/ (shorter) < /kt/ (longer)). There are several implications associated with the results from Korean non-assimilating contexts. First, Korean can be better explained in the way of its language-specific gestural pattern; gestural overlap in Korean is not simply attributed to order contrast (front-to-back vs. back-to-front) or a physiological motor constraint on lingual articulators (lingual-lingual vs. nonlingual-lingual). Taking all factors into consideration, inter-gestural coordination is influenced not only by C1 (place of articulation) but also C2 (manner of articulation). Second, the jaw articulator could have been a factor behind a distinctive gestural overlap pattern in different C1C2 sequences (/ks/ (less overlap) vs. /kt/ and /pt/ (more overlap)). A language-specific gestural pattern occurred with reference to a physiological motor constraint on the jaw articulator.

• Journal of Environmental Health Sciences
• /
• v.47 no.2
• /
• pp.166-174
• /
• 2021

Objectives: This study aimed to provide temporal Acute Exposure Guideline Levels (AEGL) for a hazardous substance as a pilot study. Methods: As one of the substances designated by the Korea Ministry of Environment as requiring preparations for potential accidents, formaldehyde was selected to estimate the AEGLs. The calculation was based on Haber's formula (Cn×t=k) using valid toxicity data (for humans/animals). A total of 96 points of AEGL levels were provided using an interval of five minutes over eight hours. Results: The AEGL-1 and 2 values were constant for the entire exposure duration at 0.9 ppm and 14 ppm, respectively. The values were obtained from clinical/animal tests, and the adaptation effect after a given exposure duration was also considered. AEGL-3 was based on animal toxicity data, and it was estimated from 127 ppm for the initial five minutes to 35 ppm for eight hours. Conclusions: More specific AEGL levels for formaldehyde could be obtained in this study using toxicity data with Haber's formula. Based on this methodology, it would be also possible to estimate AEGL levels that can be used at the scene of a chemical accident for other substances requiring preparation for potential accidents.

• Physical Therapy Korea
• /
• v.13 no.4
• /
• pp.79-86
• /
• 2006

The purpose of the current experiment was to describe interlimb coordination when swing limb conditions are being manipulated by constraining step length or by adding a 5 or 10 pound weight to the swing limb distally. Subjects were asked to begin walking with the right limb to land on the primary target (normal step length) that is 10 cm in diameter. However, if, during movement, the light was illuminated, then the subject had to step on one of the secondary targets (long and short step length). These three step length conditions were repeated while wearing a 5 pound ankle weight and then when wearing a 10 pound ankle weight. Ground reaction force (GRF) data indicated that there were changes in the forces and slopes of the swing and stance Fx GRFs. Long stepping subjects had to increase the propulsive force required to increase step length. Consequently, swing and stance toe-off greatly increased in the long step length condition. Short step length subjects had to adequately adjust step length, which decreased the speed of gait initiation. Loading the swing limb decreased the force and slope of the swing limb. Swing and stance toe-off was longest for the long step length condition, but there was a small difference of temporal events between no weight and weight condition. It appears that subjects modulated GRFs and temporal events differently to achieve the peak acceleration force of the swing and stance limb in response to different tasks. The findings from the current study provide preliminary data, which can be used to further investigate how we modulate forces during voluntary movement from a quiet stance. This information may be important if we are to use this or a similar task to evaluate gait patterns of the elderly and patient populations.

• The Journal of Korean Academy of Prosthodontics
• /
• v.40 no.6
• /
• pp.577-589
• /
• 2002

There are several variations in normal mastication. In them, unilateral mastication is chewing, predominantly on a preferred side of the dentition and hardly on e non-preferred side. Continual unilateral mastication may alter the coordination of masticatory muscles. Although they studied about these EMG of masticatory muscles, there were no information about characteristics of masticatory muscle activity in unilateral mastication. Therefore, In this study, we investigated the activity of the masseter and anterior temporal muscles during rest, clenching in maximum intercuspation and gum chewing in habitually unilateral mastication group compared with normal group and tried to know effects of continual unilateral mastication on activity of masticatory muscles. The results of this study were as follows 1. In electromyographic activity during rest, in bilateral mastication group pattern of muscle activity of right and left side was symmetrical. But, in unilateral mastication group, records of anterior part of temporal muscle was higher than that of bilateral mastication group (p<.01) and patterns of muscle activity of right and left side in both muscle were asymmetrical.(p<.05) 2. In electromyographic activity during clenching in maximum intercuspation, records of superficial part of masseter muscle were higher than anterior part of temporal muscle in both group. Muscle activity of temporal muscle in unilateral mastication group was a little higher han bilateral mastication group and asymmetry of activity pattern in temporal and masseter muscle was shown but these differences were not statistically significant. (p<.05) 3. In electromyographic activity during gum chewing, temporal muscle was activated earlier than masseter muscle and maximum bite force is derived from masseter muscle in both group. In unilateral mastication group, electromyographic activity of masseter and temporal muscle of preferred chewing side, regardless of right or left side chewing, was higher than that of bilateral mastication group and especially, difference in masseter muscle was statistically significant. (p<.01) Based on the above results, our study suggested that recording of masticatory muscle activity will be helpful in the effective diagnosis and treatment of some types of the parafunctional habits.