• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.305-314
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• 2012

The purpose of this study was to investigate the effects of joint kinetics and coordination on within-individual differences in maximum vertical jump. 10 male subjects aged 20 to 30 performed six trials in maximum vertical jump and with based on jump height the good(GP) and bad(BP) performances for each subject were compared on joint kinetics of lower extremity and coordination parameters such as joint reverse and relative phase. The results showed that maximum moment, power, and work done of hip joint and maximum moment of ankle joint in GP were significantly higher than that in the BP but no significant differences for the knee joint. We could observe a significant difference in joint reverse timing between both conditions. And also the relative phase on ankle-knee and ankle-hip in GP were significantly lower than that in the BP, which means that in GP joint movements were more in-phase synchronized mode. In conclusion, mechanical outputs of hip and ankle joints had an effect on within-individual differences in vertical jump and the inter-joint coordination and coordination including sequence and timing of joint motion also might be high influential factors on the performances within individual.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.251-255
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• 2019

On today, Protocol reverse-engineering technique can be used to extract the specification of an unknown protocol. However, there is no standardized method, and in most cases, the extracting process is executed manually or semi-automatically. If the information about the structure of an unknown protocol could be acquired in advance, it would be easy to conduct reverse engineering. the feature extraction is an important step in unknown protocol classification. However, in this paper, we present a comparison several feature extraction techniques and suggests a method of feature extraction algorithm for recognizing unknown protocol. In order to verify the performance of the proposed system, we performed the training using eight open protocols to evaluate the performance using unknown data.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.3 s.3
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• pp.123-136
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• 2001

The purpose of application of moment tensor inversion method is to determine source parameters, such as, focal mechanism, seismic moment and source depth. This paper presents results of focal mechanism solutions of 14 recent events with magnitudes ranging from M3.3 to M4.8 by using moment tensor inversion method called TDMT_INV. The strike of faults is in the direction of NE-SW and NW-SE with the movement of strike-slip or strike-slip of minor reverse component. The compressional axis of the stress field is predominantly E-W or ENE-WSW except for some faults, which are distributed at Ryongnam Massif and Wonsan, they have a compressional axis of N-S or NNW-SSE.

• Journal of Welding and Joining
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• v.28 no.5
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• pp.64-68
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• 2010

The purpose of this study is to develop the control technology of global distortion in the deck of superstructures during manufacturing processes. The behavior of global distortion in the deck was evaluated by FEA and verified through comparing with the measured results by 3D measuring instrument. It was seen from the results that the principal factor inducing the global distortion is to be the bending moment associated with the longitudinal shrinkage force and transverse shrinkage caused by welding of stiffeners and flame heating to correct the excessive local out-of-plane distortion. Based on the results, the amount of reverse distortion in the thin deck plate was determined to control the global distortion in the deck plate. The proposed distortion control technology was verified by applying it to the actual structure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.317-326
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• 2002

Recently a simple design method for rib-reinforced seismic steel moment connections has been proposed based on equivalent strut model. An experimental program was implemented to verify the proposed design method and to develop the schemes that will prevent the cracking at the rib tip, where stress concentration was evident. All the specimens designed by the proposed method were able to develop satisfactory connection plastic rotation of 0.04 radian. Slight beam flange trimming, in addition to rib reinforcement, pushed the plastic hinging and local buckling of the beam away from the rip tip and effectively reduced the cracking potential at the rib tip. The strut action of the rib and resulting reverse shear in the beam web were also experimentally identified through the strain gage readings.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.85-88
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• 2004

In this study, a simple moment-resisting precast concrete beam-column connection is proposed for highly seismic zone using dywidag ductile rod [DDC]. DDC is superior system for ductility, energy dissipation capacity, connection strength, and drift capacity. A study was carried out to investigate the connection behavior subjected to cyclic inelastic loading. Four Precast beam-column interior connections and one monolithic connection will be tested. The variables will be examined were the strength relationship between joint's ductile rod and beam reinforcement for gain energy dissipation capacity. The specimens will be tested only reverse cyclic loading in accordance with a prescribed displacement history. Connection performance is evaluated on the basis of ductility, energy dissipation capacity, connection strength, and drift capacity. the precast connection using DDC is capable of matching of exceeding the performance of the monolithic connection and thereby provides moment-resisting behavior.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.20-25
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• 2002

본 논문은 대 변형 굽힘에 의한 소성 모멘트의 계산시 ovality를 고려한 파이프의 중립축에 대한 모멘트에 관해 논한다. 기존의 계산방법에 의한 중립축에 대한 모멘트 계산결과와 새로운 방법에 의한 계산결과를 비교해 보았다. 파이프가 길이방향의 모멘트에 의하여 굽어질 때, 증가하는 모멘트에 따른 ovality 변화를 고려하여 중립축에 대한 모멘트 계산에 적용해 보았다. 모멘트 계산은 타원형의 파이프 단면을 미세한 단면으로 나누어서 각 단면에 대한 응력을 비선형 strain-stress 식을 이용하여 구한 다음 중립축에 대해 계산을 수행하였다. 대 변형 굽힘에서 일어나는 실제현상 중 하나인 ovality를 파이프의 계산에 적용함으로써 좀 더 정확한 중립축에 대한 모멘트를 계산할 수 있었다. 이 방법을 reel에 의한 해저배관의 설치 공법에서 사용되는 reverse bending radius 계산에 적용해 보았다.

• The KSFM Journal of Fluid Machinery
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• v.3 no.4 s.9
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• pp.52-58
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• 2000

The numerical study on the waterhammer was carried out for the intake pumping station of the metropolitan water supply 6th stage project. Because the waterhammer problems as a result of the pump power failure were the most important, these situations were carefully investigated. The surge tank and the stand pipes effectively protected the tunnels md the downstream region of pipeline from the pressure surge. In case the moment of inertia of the pump and motor was above $5080\;kg{\cdot}m^2$, the column separation did not occur in the pipeline between the pumping station and the inlet of 1st tunnel. As the moment of inertia increased, the pressure surges decreased in the pipeline conveying raw water. The pump control valve was chosen as the main surge suppression device for the intake pumping station. After power failure, the valve disc should be rapidly closed in 2.5 seconds and controlled the final closure to 15 seconds by the oil dashpot. If the slamming happened to the pump control valve, there was some danger of this system damaging. As the reverse flow through the valve increased, the upsurge extremely increased.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.200-208
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• 1999

The statics relation of the Stewart platform has been investigated from the viewpoint of the forward and inverse force transmission analyses. Two eigenvalue problems corresponding to the forward and inverse force transmission analyses have been formulated. The forward force transmission analysis is to determine the ranges of the magnitudes of the force and moment generated at the end-effector for the given magnitude of linear actuator forces. In reverse order, the inverse force transmission analysis is to find the range of the magnitude of actuator forces for the given ranges of the magnitudes of the force and moment at the end-effector. The inverse force transmission analysis is important since it can provide a designer with a valuable information about how to choose the linear actuators. It has been proved that two eigenvalue problems have a reciprocal relation, which implies that solving either of the eigenvalue problems may complete the forward/inverse force transmission analysis. A numerical example has been also presented.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.6
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• pp.33-39
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• 2007

The seismic source parameters of the Uljin earthquake on 29 May 2004, including focal depth, focal mechanism, magnitude, and moment tensor elements for source characteristics, are analysed using moment tensor seismic source inversion. The Green‘s function for 3 crust models representing the southern Korean Peninsula are used. Also 3 kinds of epicenters are used to find optimum solution for seismic source parameters. Results show that seismic source parameters have a little dependency of azimuthal distribution and epicentral distances of seismic stations. Final results show that the event, considering 6 moment tensor elements, is caused by the typical reverse fault with nearly NS strike. The focal mechanism implies that the tectonic force around epicenter area currently has compressive environment, with nearly EW principal axis. The focal depth is estimated to be about 12km. The resultant focal mechanism show fairly good agreement to those of other studies. However, focal depth is much different from that of other studies.