• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.90-99
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• 1995

A numerical method is proposed to synthesize automotive cam profiles. An arbitrary acceleration profile for the cam follower motion is divided into several segments, each of them is described by a Hermite curve. A cam profile is defined by control point locations and control variables assigned to each segment. Closed form equations are derived for velocity and displacement constraints which should be satisfied for the curve to be a cam profile. Because the method is flexible and provide arbitrary local controllability, any types of cam acceleration profile can be reproduced by the method. The method is expecially useful for the design of roller type OHC valve trains which need precise local control in the cam profile design to avoid under-cutting problems.

• Computers and Concrete
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• v.10 no.1
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• pp.35-47
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• 2012

The ideal gradating curve is used in this study to estimate densified aggregate blended ratio and total surface area of aggregate, there by under assigned paste amount of concrete, and coating paste thickness can then be deduced. Four groups of concrete mixtures were prepared and the corresponding concrete properties, such as workability, compression strength, ultrasonic velocity, surface resistivity and chloride ion penetration, were measured and finally the results are interpreted in terms of "coating thickness". The result shows as the coating thickness of the concrete is higher than critical one, the coating thickness on aggregate does affect the workability, and whatever workability is required the superplasticizer can be adjusted to achieve the demand workability. Under a fixed paste quality at the same age, coating paste thickness is inversely proportional to the concrete properties, especially as the coating thickness gets thinner.

• Journal of Auto-vehicle Safety Association
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• v.15 no.2
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• pp.21-27
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• 2023

This paper presents a simulation tool for developing and evaluating automated driving systems' lane change algorithm in urban congested traffic. The behavior of surrounding vehicles was modeled based on driver driving data measured in urban congested traffic. Surrounding vehicles are divided into aggressive vehicles and non-aggressive vehicles. The degree of aggressiveness is determined according to the lateral position to initiate interaction with the vehicle in the next lane. In addition, the desired velocity and desired time gap of each vehicle are all randomly assigned. The simulation was conducted by reflecting the cognitive limitations and control performance of the autonomous vehicle. It was possible to confirm the change in the lane change performance according to the variation of the lane change decision algorithm.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.2
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• pp.203-210
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• 2022

Purpose : The purpose of this study was to investigate the effect of vestibular sensory stimulation exercise on the limit of stability, dynamic weight shift, and upper and lower extremities reaction time in adult women. Methods : This study was conducted with 30 female. All subjects were randomly and equally assigned to an experimental group and a control group of 15 each. Subjects assigned to the experimental group received vestibular sensory stimulation training for 6 weeks. For the intervention, vestibular sensory stimulation exercises were conducted by referring to the Hamid exercise method and the Cawthorne-Cooksey exercise method, and the control group did not receive any intervention. All subjects were tested for limit of stability, dynamic weight shift, and upper and lower extremities reaction time before and after the intervention. Results : The results of this study showed significant differences between groups in reaction time, moving velocity, and directional control in the limit of stability test after intervention. In the dynamic weight shift test after intervention, there was a significant difference between the groups in the slow directional control of left and right. And in the upper and lower extremities reaction time test after intervention, both scores and reaction time showed significant differences between groups. Conclusion : As a result, the three vestibular sensory stimulation exercises applied in this study improved the limit of stability, dynamic weight shift, and upper and lower extremities reaction time.

• Journal of Korean Neurosurgical Society
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• v.30 no.8
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• pp.970-975
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• 2001

Objective : By conducing a review of clinical outcomes for patients with aneurysm treated using current microneurosurgical techniques and intensive care unit management, we speculated that grading systems based only on clinical condition or CT finding after admission failed to provide a significant stratification of outcome between individual grades of patients, because these systems did not include the factor for postoperative vasospasm. We hypothesized that postoperative blood flow velocity could have a significant impact on outcome prediction for patients surgically treated for intracranial aneurysms. Methods : We conducted a analysis on patient- and lesion-specific factors that might have been associated with outcome in a series of 55 aneurysm operations performed with measurements of blood-flow velocity with transcranial Doppler ultrasonography(TCD). In the new scale(NS) score system, 1 point is assigned additionally for the case with Hunt and Hess(H-H)/World Federation of Neurological Surgeons(WFNS) Grade IV or V, Fisher Scale(FS) score 3 or 4, aneurysm size greater than 10mm, patient age older than 60 years, blood-flow velocity higher than 120cm/sec, and posterior circulation lesion. By adding the total points, a 6-point scale score(score 0-6) is obtained. Results : Age of patient, size of aneurysm, clinical condition(H-H grade and WFNS), FS score, and blood flow velocity(TCD 1day after operation) were independently and strongly associated with long-term outcome. When NS scores were applied to 55 patients with at least 6 months follow-up, the correlation of individual scores with outcome was strongly validated the retrospective findings. Conclusion : It was speculated that TCD could be used to assess postoperative vasospasm and to monitor noninvasively the patients with aneurysmal SAH. This NS score system is easy to apply, divide patients into groups with different outcome, and is comprehensive, allowing for more accurate prediction of surgical outcome.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.142-145
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• 2003

Many control applications using Neural Network need a priori information about the objective system. But it is impossible to get exact information about the objective system in real world. To solve this problem, several control methods were proposed. Reinforcement learning control using neural network is one of them. Basically reinforcement learning control doesn't need a priori information of objective system. This method uses reinforcement signal from interaction of objective system and environment and observable states of objective system as input data. But many methods take too much time to apply to real-world. So we focus on faster learning to apply reinforcement learning control to real-world. Two data types are used for reinforcement learning. One is reinforcement signal data. It has only two fixed scalar values that are assigned for each success and fail state. The other is observable state data. There are infinitive states in real-world system. So the number of observable state data is also infinitive. This requires too much learning time for applying to real-world. So we try to reduce the number of observable states by classification of states with Self-Organizing Map. We also use neural dynamic programming for controller design. An inverted pendulum on the cart system is simulated. Failure signal is used for reinforcement signal. The failure signal occurs when the pendulum angle or cart position deviate from the defined control range. The control objective is to maintain the balanced pole and centered cart. And four states that is, position and velocity of cart, angle and angular velocity of pole are used for state signal. Learning controller is composed of serial connection of Self-Organizing Map and two Multi-layer Feed-Forward Neural Networks.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.6 no.1
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• pp.69-79
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• 2008

In this paper, the effects of the external-rotation exercise on the gait of hemiplegia was investigated. 26 patients with hemiplegia due to cerebrovascular accident participated in this study. Subjects were randomly assigned to experimental group(n=12) and control one(n=14). 12 subjects of the experimental group were received the external rotation reducing exercise on the mat with seating and supine posture after the general therapeutic exercise for hemiplegia. 14 subjects of the control group were received only general therapeutic exercise. The effects of external rotation reducing exercise were evaluated by measurements of gait velocity, cadence, stride length, step length and foot angle using ink-foot prints. The collected data were analyzed statistically based on Wilcoxon, Mann-Whitney and correlation analysis. After treatment of three weeks, it turned out that external rotation reducing exercise has the significant effect on foot angle(p<0.01). However the exercise has no statistically significant direct effect on the gait velocity, cadence, stride length and step length.

• Physical Therapy Rehabilitation Science
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• v.5 no.4
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• pp.205-209
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• 2016

Objective: Children with spastic diplegic cerebral palsy show weakness especially in the lower-extremity rather than upper-extremity muscles and display characteristics such as asymmetric alignment, deficits in postural control or balance ability, and slow walking speed. Various therapeutic interventions are applied to children with cerebral palsy, of which taping is widely used in the field of rehabilitation, however, there are few studies of the effects of kinesio taping on gait patterns of children with cerebral palsy. The present study investigated the effects of kinesio taping on gait parameters of children with cerebral palsy. Design: Cross-sectional study. Methods: Four children with spastic diplegia participated in this study. The participants' gait parameters while walking 10 m with and without kinesio taping (tibialis anterior, quadriceps femoris, and gluteus maximus) were recorded. Gait parameters including gait velocity, cadence, step length, stride length, single support time, and double support time were evaluated using the GAITRite. Mean values were obtained after having the subjects walk three times in each condition with a 5-minute rest period between each condition. The order of each condition was assigned randomly. Results: There were significant improvements in gait velocity, step length, stride length, and single support time of the right leg with kinesio taping condition compared to the without kinesio taping condition taping (p<0.05). However, there were no significant differences in cadence, single support time of the left leg, or double support time. Conclusions: The results show that kinesio taping may have a positive effect for improving gait parameters of children with spastic diplegia. However, its usefulness in the rehabilitation of children with cerebral palsy needs to be further investigated.

• Physical Therapy Rehabilitation Science
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• v.7 no.3
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• pp.127-133
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• 2018

Objective: The purpose of this study was to investigate the effects of foam roller (FR) stretching, kinesiotaping (KT), and dynamic stretching (DS) on gait parameters after inducing muscle fatigue in the ankle joint. Design: Cross-sectional study. Methods: The subjects were thirty healthy young adults between the ages of 20 and 31 years at Baekseok University who voluntarily participated in this study. The participants were randomly assigned to either the FR group, KT group, or the DS group after inducing muscle fatigue of the ankle joint. Fatigue induction of the ankle joint muscles was performed by alternating a heel up and down exercise with the standing posture on the ground. The speed was maintained at 40 beats/minute using a metronome. Subsequently, the respective intervention was applied to each group. Gait parameters were measured before and after ankle muscle fatigue induction, and after intervention using the GAITRite system. One-way ANOVA was used to compare gait parameters among groups, while repeated measures ANOVA was used to compare gait parameters within each intervention group. Results: The FR group increased significantly in velocity, step length, and stride length except for cadence after intervention compared to after ankle muscle fatigue induction (p<0.01). Furthermore, the KT group showed significant increases in velocity, cadence, step length, and stride length after intervention, especially in cadence group (p<0.05). All intervention groups showed significant increases in stride length after intervention, especially the DS group (p<0.05). Conclusions: Therefore, we suggest that KT, FR, and DS can be an effective intervention on gait parameters when the ankle joint is unstable and injured.

• Journal of the Korean Society of Physical Medicine
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• v.3 no.4
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• pp.215-224
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• 2008

Purpose : The purpose of this study was to evaluate the effects of the Hahoe mask dance on the gait and muscle activity in the elderly who lived at a elderly welfare facility. Methods : Dancing group was consisted of 20 subjects(over 70 years). The time of measurement was assigned in pre measurement, after 1 month, after 2 months. Subjects was received the Hahoe mask dance for three times a week during 8 weeks. The control group was consisted of 20 the elderly (similar age) who didn't received dancing. Assessment of gait function included the gait velocity, step time, stride, step length, it was analyzed in activity for 4 muscles (rectus femoris, biceps femoris, tibialis anterior, and lateral gastrocnemius). Results : Activities for muscles of control group was decreased in rectus femoris, bieps femoris, however, those of experimental group was increased significantly(p<.05). While control group showed decrease in the gait velocity per second (p<.05), experimental group showed statistically significant increase(p<.05). Control group had a significant long time than that of control group in gait time of right and left foot(p<.05). Control group was a little longer than control group in stride time of right and left foot(p<.05). Step length for control group was shorter than that for experimental group both foots(p<.05). Conclusion : In conclusion, this study confirmed that activities for 4 muscles by EMG have showed significant increases, so we will use a programme of muscle improvement in elderly community welfare faculty. We recommend that further research should explore the degree of muscle activity by larger sample sizes and longer follow-up periods.