• Journal of Korean Neurosurgical Society
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• v.66 no.4
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• pp.476-481
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• 2023

Objective : The latest version of the Leksell Gamma Knife Icon^TM allows for mask- and frame-based fixation. Although mask fixation provides fractionated treatment and immobilization using a noninvasive method, it is not free from collision. The authors investigated the collision problem with a modified mask fixation method. Methods : This study presents a case of two meningiomas in the frontal area, where a collision occurs in the occipital area. A modified mask fixation method was introduced to avoid the collision : first, the edges of the head cushion were cut off and polystyrene beads with a diameter of approximately 5 cm were removed. Next, the head cushion was sealed using a stapler. Finally, the head cushion was flattened in the adapter. We compared the shot coordinates, 3-dimensional (3D) error, clearance distance, and vertical depth of the head cushion between the initial and modified mask fixations. Results : When comparing the initial and modified mask fixations, the difference in the shot coordinates was +10.5 mm along the y-axis, the difference in the 3D error was approximately 18 mm, and the difference in clearance was -10.2 mm. The head cushion was approximately 8 mm deeper in the modified mask fixation. Conclusion : Based on these findings, we recommend a modified mask fixation method for gamma knife radiosurgery using ICON with a collision.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.435-439
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• 2002

In the pneumatic system, pneumatic cylinder is wildly used to factory automation. In general, Pneumatic cylinder problems are occured with colliding to stroke end part at which piston collide to end-cap, head cap and tube when piston is loading. This appearances have a short life of cylinder and is due to system destruction. This study examines the dynamic characteristics of pneumatic cushioning cylinder and cushion sleeve design. At head part cushion chamber for the vertical experimental, The decisions of cushioning effect and the results of the experimental research are obtained to the followings: i) The cushioning effects could acqure to the reserch, if the compressible energy is more than kinetic ones. ii) The collision of piston and head cover could acqure to the research, if the kinetic energy is more than compressible iii) If the load increase to the rolling car, the cushion region pressures would increase and the dynamic force.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.2
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• pp.179-193
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• 2012

The development of modern transportation technology has required many people in spaces (such as vehicle seats, airports, and train stations) for long periods. The public seats provided in these places are manufactured in a standard size; however, fatigue sets in if the seats are unsuitable for the person's physical size. For this reason, this study developed an air cushion vest that would enhance the comfort of vehicle seats. Passengers in vehicles, trains, airplanes, and buses were observed and surveyed to understand the demand for seat comfort. Our analysis found that the greatest source of discomfort was involuntary nodding of the head while asleep and discomfort around the waist area. For this reason, the air cushion vest was designed to support the head and the waist. The neck cushion of this vest was designed to strengthen head support to counter forward nodding because existing commercial neck cushions had no support for forward nodding. For the waist cushion, at lumbar and below-lumbar parts were chosen as the key parts to be supported, the cushion was designed to contain air at those parts. To cover the embedded waist cushion, the vest was designed to be long. The closure was constructed with zippers from the neck to waistline, and with invisible snaps from the waistline to the hemline so that the wearer could open them easily while seated. A subjective comfort evaluation was conducted to verify the effectiveness of the developed vest. In the test, the developed cushions received a better evaluation than cushions currently available on the market. The volume of the vest could be adjusted by the inflow and outflow of air. It was proven that the vest was effective in terms of comfort and portability. This shows that the developed vest could enhance passenger comfort while sitting on vehicle seats.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.1
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• pp.76-80
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• 2004

Cushion sleeves are used in pneumatic cylinders to avoid impact force arising at the end stroke part between moving piston and cylinder cover. In this study low kinds of cushion sleeves are designed, manufactured and attached to the pneumatic cylinder to be experimented. The effects of cushion sleeves on cushion characteristics are investigated. e results are as follows; the pressure variation of cushion room with orifices are inspected to be smaller than that of cushion room without orifices. So sleeves with orifices are expected as protecting from impact and vibration of pneumatic cylinder. The object of this study is to provide data on the charactristics of pneumatic cushion sleeve in case of being used in industry.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.49-57
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• 2008

The performance of crash cushion systems is certified through the full scale crash tests by the standard for installation and maintenance guidelines for roadside safety appurtenance. The impact severities of impacting vehicles in collision with crash cushion systems are rated by indices THIV and PHD. Crash test results are considered to study the performance of three crash cushion systems. In case of the frontal impact or the offset frontal impact, the results show that THIV values of three systems are very close to the threshold limit for the occupant protection. Also, the results show that PHD would be improper for the occupant protection performance index. In order to improve the occupant protection performance of crash cushions, ASI needs to be included in the impact severity index.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.120-126
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• 2018

The traffic accident types are largely classified into vehicle to vehicle accident, vehicle-to-person accident and single-vehicle. Especially, the single-vehicle accident types are severe when the vehicle crashed into road facilities such as bridge, piers, utility poles. The severity of single-vehicle accidents are ten times higher than that of all other accidents types. It is needed to consider to reduce accident severity. This study was conducted to develop crash worthy safety design facility to ensure the vehicle occupant safety. The simulation and the crash tests were conducted for assessment of the safety performance to check the criteria of CC2(Crash Cushion 2) level. THIV(Theoretical Head Impact Velocity) and PHD(Post-impact Head Deceleration) were used to assess occupant impact severity for crashes. The non-redirection collision test conditions for 900 kg and 1,300 kg-head on crash tests, 900 kg-1/4 offset crash tests, 1,300 kg-head on crash test with $15^{\circ}$angle were conducted. The simulation and experiment test result showed that THIV values were below 44 km/h criterion, PHD values were below the 20G. The development non-redirective crash cushion is expected to be used for the fixed object such as bridge piers for assuring occupant safety.

• Tribology and Lubricants
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• v.29 no.1
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• pp.7-12
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• 2013

Turbine power control devices at a nuclear / thermoelectric power plant lead to failure by creating mechanical shocks and strong vibrations that are due to the strong elasticity of a spring and the inertia of the valve face during its rapid movement to block steam. To ensure durability of the turbine power control device, which is the main component in the power plant, it is necessary to develop a device that can prevent such vibrations. In this study, a cushion mechanism is added to the head of the hydraulic servo actuator, which is a turbine power control device. Moreover, the cushion mechanism, which includes various modifies shapes and orifices is investigated dynamically through modeling and simulations.

• Journal of Auto-vehicle Safety Association
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• v.6 no.2
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• pp.55-60
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• 2014

To verify the performance of roadside safety facilities, strength and occupant protection test are performed by evaluation criteria. Strength test use a truck and occupant protection test use a sedan. Strength perfomance is analyzed pass rate by post lateral resistance of the safety barrier. Occupant protection performance is analyzed from THIV(Theoretical Head Impact Velocity) and PHD(Post-impact Head Deceleration) by crash cushion test.

• Journal of the Semiconductor & Display Technology
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• v.13 no.3
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• pp.57-60
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• 2014

The distortion correction system of Head up display that is installed in vehicle has been studied both experimentally and theoretically for the removal of the optical lens distortion. A new adaptive correction method is having a decisive effect on correction in the optical lens distortion of Head up display. This adaptive correction system removes various distortion that has occurred because of the design tolerances of Head up display and the assemble tolerances into vehicle. It is especially efficient in removal of a barrel distortion and pin cushion of Head up display.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.33-43
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• 2006

Driving tests using model plastic piles with different hammer cushion materials were performed in order to evaluate the efficiency of energy transfer ratio from the hammer, degree of vibration of the surrounding ground and noise due to impacting. A small pile driving analyzer (PDA) was composed using straingages and Hopkinson bar which is measuring force signal and pile-head velocity. The hammer cushion (cap block) materials used for the model driving tests were commercial Micarta, plywood, polyurethane, rubber (SBR) and silicone rubber. The highest energy transfer ratio was obtained from Micarta in the same soil and driving conditions. Micarta was followed by polyurethane, plywood, rubber and silicone in descending order. The more efficient energy transfdr ratio of the hammer cushion materials became, the bigger average noisy (sound) level was found. In addition, Micarta and polyurethane provided bigger bearing capacities than other materials compared in the same soil and driving conditions in which the static loading tests were performed at the end of driving.