• Proceedings of the KSME Conference
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• 2003.11a
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• pp.115-120
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• 2003

In this study, smoke movement in tunnel fires was investigated with various aspect ratio(0.5, 0.667, 1.0, 1.5, 2.0) of tunnel cross section. Reduced-scale experiments were carried out under the Froude scaling using 8.27 kW ethanol pool fire. Temperatures were measured under the ceiling and vertical direction along the center of the tunnel. Smoke front velocity and temperature decrease rate were reduced as higher aspect ratio of the tunnel cross-section. Smoke movement was evaluated by analysis of vertical temperature distribution 3 m downstream from the fire source. Elevation of smoke interface according to N percent rule was under about 60% of tunnel height.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.474-474
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• 2000

This paper shows that a system with two-link arm can obtain hand reaching movement to a target object projected on a visual sensor by reinforcement learning using a layered neural network. The reinforcement signal, which is an only signal from the environment, is given to the system only when the hand reaches the target object. The neural network computes two joint torques from visual sensory signals, joint angles, and joint angular velocities considering the urn dynamics. It is known that the trajectory of the voluntary movement o( human hand reaching is almost straight, and the hand velocity changes like bell-shape. Although there are some exceptions, the properties of the trajectories obtained by the reinforcement learning are somewhat similar to the experimental result of the human hand reaching movement.

• Journal of Biomedical Engineering Research
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• v.6 no.2
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• pp.23-28
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• 1985

In this paper, the the duration of horizontall saccadic eye movement is studied alls measurement system is designed using microprocessor to obtain the quantitized data The duration is measured using the beginning and ending points of the saccadic velocity threshold. The results obtained are as follows. 1. The average duration of the saccade for angle displacement of 0$^{\circ}$ to 20$^{\circ}$ lies between 25 and 60 msec, and represents the increasing curve except 9$^{\circ}$ and 12$^{\circ}$ 2. The average duration lfor angle displacement of 5$^{\circ}$,10$^{\circ}$,15$^{\circ}$, and 20$^{\circ}$ is 40, 48, 57.5, and 62 msec, respectively. 3. Nasal movement has a little longer duration than temporeal movement. 4. The duration is not concerned with subject's will.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1410-1419
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• 2018

A skier's motion was analyzed by a simple model consist of point mass m and a single rod connected to a single ski plate. We studied the conditions for the stable ski turn as functions of the linear velocity and the radius of the turn. The solutions for the stable ski turn in our model do not require any extra skier's movement to complete a stable circular turn. The solution may then give the skier the most comfortable skiing method without any active movement to control the ski. The generalized force supporting the point mass from the ski plate was calculated. We obtained the force from the ground (rebound force) without any geometrical structure of the ski plate. Adding an active movement to the direction of the ski plate, the conditions for the stable ski turn were also analyzed. Our result gives some insight for the skier who wants to develop technique.

• Journal of Korea Water Resources Association
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• v.41 no.4
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• pp.423-432
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• 2008

The local migration or movement behavior of fishes in streams are related to feeding, spawning, growing, dispersing, and refuging. The pale chub (Zacco platypus) is a dominant species that migrates locally and inhabits in river and stream in Korea. However, dams, weirs, culverts and other regulatory structures are physical barriers that limit fish movement and fragment habits and populations. If main stream and off-channel habitats are connected with culverts, they would restrict the small fish as pale chub movement due to the high flow velocities and low depths. But in Korea, there is no experimental study to evaluate the swimming performance of species in Korea. Therefore, it is difficult to proposed that design guidelines for pass fishes through culverts. The purpose of this experimental study is to evaluate the swimming performance of pale chubs. A series of swimming performance test has been used in both of the fixed velocity and the incremental velocity methods in an experimental flume. As a result, the critical swimming speed for pale chub(body length 8.9 cm) was found to be about 0.7 m/s. Therefore, the flow velocity for culvert design in the low flow condition should not be exceed the its swimming ability, especially 0.7 m/s for pale chubs(body length 8.9 cm). And the minimum depth for culvert design in the low flow condition should not be lower than the fish body height add a dorsal fin height.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.311-322
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• 2015

Objective : The purpose of this study was to investigate the effects of landing height and knee joint muscle fatigue on the movement of the lower extremity during cutting after landing. Method : Subjects included 29 adults (age: $20.83{\pm}1.56years$, height: $172.42{\pm}9.51cm$, weight: $65.07{\pm}10.18kg$). The subjects were asked to stand on their dominant lower limb on jump stands that were 30 and 40 cm in height and jump from each stand to land with the dominant lower limb on a force plate making a side step cutting move at a $45^{\circ}$ angle with the non-dominant lower limb. The fatigue level at 30% of the knee extension peak torque using an isokinetic dynamometer. Results : The results showed that the difference of landing height increased maximum range of motion and angular velocity of hip, knee, and ankle joints in the sagittal plane, and in the angular velocity of motion of the hip joint in the sagittal plane. The maximum range of motion of the knee joint in the sagittal plane and the frontal plane decreased on landing from both heights after the fatigue exercise. The angular velocity of the hip joint in the sagittal plane, and the maximum range of motion of the hip joint in the transverse plane decreased for both landing heights after the fatigue exercise. The angular velocity of the hip joint in the frontal plane decreased for the 30 cm landing height after the fatigue exercise. On the other hand, the angular velocity and maximum range of motion of the ankle joint in the sagittal plane for both landing heights, and the angular velocity and maximum range of motion of the ankle joint in the frontal plane increased on landing from the 40 cm height after the fatigue exercise. Conclusion : Different landing heights of 30 and 40 cm and 30% fatigue of peak torque of knee extensor found a forefoot and stiff landing strategy, when cutting after landing. These results might be due to decline in the shock absorption capability of the knee joint and the movement capability related to cutting while increasing the contribution of the ankle joint, which may cause increased ankle joint injuries.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.277-291
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• 2003

This study was designed to examine the kinematic factors in the phase during the marche fente motion. For this study, the subjects were 5 elite male fencing players. The direct linear transformation (DLT) method was used in calculating 3-D coordinate of the digitized body parts. The cubic spline function was used for smoothing and the kinematic data for displacement, velocity, angle variables were calculated for Kwon3d ver 2.1. And the following conclusions were drawn; 1. It show that the marche phase appeared to longer time than the pante phase In the performance time. For the fast attack, it showed that the subjects should be moving in a short stride width. 2. For a fast and stable movement posture in the marche phase, the vertical change of COG must be maintain the same position as possible, but all subjects appeared to decrease the COG because of a excessive the knee flection. 3. In the COG velocity change, all the subjects showed to the same change in both the marche and the fente phase. However in the attack extremity velocity, it increased velocity in order of upper arm, fore arm, and hand in the marche phase, but it showed different velocity among each subjects at the moment of stabbing. So that in order to do effective stabbing, they have to extend their upper extremity max and do faster the distal segment than the proximal segment. 4. It showed to take a fast and stable movement, because some subjects showed the big anteroposterior angle of the trunk flexed max shoulder angle and elbow angle of their attack arm and the other upper extremity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2114-2118
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• 2010

The purpose of this study was to analyze bradykinesia of toe tapping movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. 39 PD patients (age: $65.5{\pm}11.2$ yrs, H&Y stage:$2.3{\pm}0.5$), 14 eldelry subjects with comparable mean age ($65.0{\pm}3.9$ yrs) and 17 healthy young subjects ($24.1{\pm}2.1$ yrs) participated in this study. Angular velocity during repetitive toe tapping movement was measured in both feet using a gyro sensor system. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity signal. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.02). All measures were significantly correlated with UPDRS scores(r=-0.689~-0.825). These results suggest that the developed system can be used as quantitative measures of the lower limb bradykinesia in PD patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.308-316
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• 2006

Objectives Despite considerable advances in technique, experience and skill, the precise place of surgery in the treatment of facial nerve injury remains uncertain. We designed a facial nerve crush injury model in rats and evaluated the recovery of crushed nerve which is the most common injury type of facial nerve using adenovirus vector mediated in vivo gene transfer of Brain derived neurotrophic factor(BDNF). Materials and methods In 48 Sprague Dawley rats, we made a facial nerve crush injury model to main trunk before the furcation, and injected a $10^{11}$pfu adenoviral BDNF in experimental group(BDNF adenoviral injection group; ad-BDNF) and $3{\mu}l$ saline in control group(Saline injection group; saline). After a period of regeneration from 10 to 40 days, nerve regeneration was evaluated with functioinal test (vibrissae and ocular movement), electrophysiologic study(threshold, peak voltage, conduction velocity) and histomorphometric study of axon density. Results Vibrissae and ocular movement, threshold and conduction velocity improved as time elapse in both group, however axon density was increased significantly only in experimental group. Functional test in 10 days and 20 days showed no difference between experimental group and control group. Vibrissae movement, threshold, conduction velocity and axon density in 30 days revealed that the regeneration in quality of experimental group was significantly superior to that of control group. Conclusion In general, there is tendency for nerve regeneration in experimental group (BDNF-adenovirus injection group) during 40 days, functional recovery was detected successfully after facial nerve crush in 30 days postoperatively.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.449-457
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• 2006

The driver model during drift cornering was examined, and a technique to improve vehicle movement performance during drift cornering was investigated. Based on the results obtained, the driver was found to steer using feedback of the body slip angle and the body slip angle velocity during drift cornering. Moreover, improvement of the cornering force characteristic, at which exceeded the maximum cornering force calm as much as possible is important.