• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.7 no.4
• /
• pp.115-120
• /
• 2008

The fatalities of pedestrian accounted for about 40.0% of all fatalities in Korea (2005 year). In pedestrian involved accident, the most important data to inspect accident is throw distance of pedestrian. The throw distance of pedestrian can be influenced by many variables, such as vehicular frontal shape, vehicular impact speed, the offset of impact point, the height of pedestrian, and road condition. The trajectory of pedestrian after collision can be influenced by vehicular frontal shape classified into sedan type, box type, SUV type and van type. Many studies have been done about pedestrian accident with passenger car model and bus model for simple factors. But the study of pedestrian accident by van type vehicle was much insufficient, and even that the influence of multiple factors such as the offset of impact point was neglected. In this paper, a series of pedestrian kinetic simulation were conducted to inspect relationship between throw distance and multiple factors with using PC-CRASH s/w, a kinetic analysis program for a traffic accident for van type. By based on the simulation results, multi-variate regression was conducted, and regression equation was presented.

• Journal of Computing Science and Engineering
• /
• v.11 no.3
• /
• pp.92-99
• /
• 2017

Memcached, commonly used to speed up the data access in big-data and Internet-web applications, is a system software of the distributed-cache mechanism. But it is subject to the severe challenge of the loss of recently uncommitted updates in the case where the Memcached servers crash due to some reason. Although the replica scheme and the disk-log-based replay mechanism have been proposed to overcome this problem, they generate either the overhead of the replica synchronization or the persistent-storage overhead that is caused by flushing related logs. This paper proposes a scheme of backing up the write requests (i.e., set and add) on the Memcached client side, to reduce the overhead resulting from the making of disk-log records or performing the replica consistency. If the Memcached server fails, a timestamp-based recovery mechanism is then introduced to replay the write requests (buffered by relevant clients), for regaining the lost-data updates on the rebooted Memcached server, thereby meeting the data-consistency requirement. More importantly, compared with the mechanism of logging the write requests to the persistent storage of the master server and the server-replication scheme, the newly proposed approach of backing up the logs on the client side can greatly decrease the time overhead by up to 116.8% when processing the write workloads.

• Journal of Auto-vehicle Safety Association
• /
• v.9 no.3
• /
• pp.7-12
• /
• 2017

The whiplash is the most important issue of low speed rear-impact. So auto makers are committed to developing a seat to improve whiplash injury. Most NCAP tests have been used by same pulse (Mid Velocity 16kph). Only Euro NCAP uses different pulse that consists of Low, Mid, High velocity. But Euro NCAP also uses same pulse in Mid velocity as other NCAP test. That Mid velocity NCAP pulse was made by rear impact that has 90's vehicle structure properties. That pulse was used until now days. However these days, auto maker use more high tensile steel than 90's as customer and society demand more fuel efficiency and light vehicle with good safety structure. So modern vehicles have different pulse patterns of rear impact than NCAP pulse and 90's vehicle crash properties. In this paper, the test was conducted by following condition. Target car was impacted by the rigid barrier with certain velocity. Finally target vehicle gained delta V 16kph which was same velocity as NCAP Mid Velocity pulse. It is critical velocity which occur long period neck injury. It is very different pulse that was gained by real car impact from NCAP pulse. And it has higher peak G with high fluctuation and short duration than NCAP pulse.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.562-564
• /
• 2001

Transformation of molecular film occurs only usually in air-water interface, 2 dimensions domain's growth and crash are achieved. Organic matter thin film that accumulate molecular film in archaism board only that consist of growth of domain can understand correct special quality of accumulation film supplying information about fine structure and properties of matter of device observing information and so on that is surface forward player and optic enemy using AFM one of SPM application by nano electronics. The stable images are probably due to a strong interaction between the monolayer film and glass substrate. We are unable to obtain molecule resolution in images of the films but did see a marked contrast between images of the bare substrate and those with the network structure film deposited onto it. Formation that prevent when gas phase state and liquid phase state measure but Could know organic matter that molecules form equal and stable film when molecules were not distributed evenly. and accumulated in solid state only.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1618-1620
• /
• 2002

Transformation of molecular film occurs only usually in air-water interface, 2 dimensions domain's growth and crash are achieved. Organic matter thin film that accumulate molecular film in archaism board only that consist of growth of domain can understand correct special quality of accumulation film supplying information about fine structure and properties of matter of device observing information and so on that is surface forward player and optic enemy using AFM one of SPM application by nano electronics. The stable images are probably due to a strong interaction between the monolayer film and glass substrate. We are unable to obtain molecule resolution in images of the films but did see a marked contrast between images of the bare substrate and those with the network structure film deposited onto it. Formation that prevent when gas phase state and liquid phase state measure but Could know organic matter that molecules form equal and stable film when molecules were not distributed evenly, and accumulated in solid state only.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.3
• /
• pp.52-59
• /
• 2008

Most accident reconstruction or analysis depend on the coefficient of friction to estimate the vehicle speeds. Skid mark and coefficient of friction are usually utilized to calculate the velocity and behavior of vehicles. For a critical case such as traffic accident reconstruction, however, the initial velocity of the car should be calculated precisely. In this paper, emergency brake tests on ABS and Non-ABS brake system are conducted on the dry pavement asphalt road on speed 40, 60, 80 and 100 km/h respectively. The SWIFT sensor was established in the front wheel and rear wheel at driver side to measure the forces, moments and speeds of revolution of the tires. These tests results can be available to brake tests and accident reconstruction.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.7
• /
• pp.601-607
• /
• 2012

The main function of a landing gear is to absorb the impact energy during touchdown. It it occasionally required for landing gear to have crashworthiness for improving survivability and safety in case of emergency landing. This paper introduces the design concept, performance analysis and drop test procedures for the development of the crashworthy landing gear. The shock absorbing ability and the crash behavior are proved by analyzing various sensor data and video clips from high speed camera recording during drop tests.

• Applied Science and Convergence Technology
• /
• v.24 no.2
• /
• pp.27-32
• /
• 2015

We analyzed the destruction patterns of a turbo-molecular pump (TMP) resulting from its sudden exposure of a foreline to the atmospheric pressure due to a destruction of the foreline connecting clamp of an ICP dry etcher for 300 mm wafers during high-vacuum operation ($5{\times}10^{-6}$ Torr). Unlike in the case of view port's breakage, the TMP's rotor module was crashed inside the chamber. The primary damage resulted from the collision of the blades and stators, and the secondary damage resulted from the breaking of the rotor - driving shaft assembly. The fixing screws of the rotor and axial shaft were bent and broken when the TMP controller output the maximum current even after the crash event. Electrical power consumption analysis of the TMP power controller confirmed it. The stress distributions were analyzed by a finite element method using CFD-ACE+ multi physics software. Rotating inertia of each parts and kinetic energies were calculated as well. 68% of the rotational kinetic energy is deposited by the rotor - shaft module.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.6
• /
• pp.613-618
• /
• 2015

In recent years, WorldSID has been continuously developed and investigated to be the representative biofidelic anthropomorphic test device (ATD) as well as the device for replacement of the current EuroSID-2. In Korea, the side impact accident is one of the major severe accidents in terms of the number of accidents and fatality. Since 2003, the side crash test with a speed of 50 kph in the perpendicular direction has been initiated as a safety standard with EuroSID-1 at the first stage. Simultaneously, a 55 kph impact test has been conducted as a part of Korean New Car Assessment (KNCAP). Currently, only EuroSIDE-2 is accepted as a regulatory tool for vehicle certification and KNCAP. The tests with WorldSID are conducted experimentally in order to use WorldSID of the KNCAP in near future.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.23 no.4
• /
• pp.125-132
• /
• 2015

항공기 추락 시 충돌충격단계에서 사상자가 가장 많이 발생하는 것으로 나타나고 있다. 대부분의 경우, 승객들은 두부손상으로 의식을 잃게 되어 비상탈출에 실패하여 사망에 이르게 된다. 이에 대한 대응책으로 항공기 제작사들은 내구성이 강화된 항공기 좌석을 설계 및 제작하여 설치하고 있다. 객실에서는 승객들이 충격방지자세를 취함으로써 부상을 최소화할 수 있다. 승객들에 대한 충격방지자세 안내는 모든 항공사가 시간적 여유가 있는 비상상황에서만 객실승무원이 안내방송과 함께 시범을 보이도록 절차가 수립되어 있다. 그러나 갑작스런 사고의 경우 승객들은 충격방지자세에 대한 정보를 전달받지 못한 상태에서 사상의 위험에 직면하게 된다. 본 논문은 SHEL 모델을 적용하여 승객과 사상자발생 환경, 승객과 충격방지를 위한 안전절차, 승객과 승객안전정보 전달매체, 승객과 객실승무원등의 상호작용에 내재된 위해요소를 체계적으로 규명하고 객실안전에 대한 법규 및 절차 등의 개정을 제시함으써, 항공기사고로 인한 사상자 발생에 대한 근본적인 대안을 제시하여 항공안전 증진에 기여하고자 한다.