• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.375-383
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• 2014

The purpose of this study was to assess the inter-segmental trunk motion during which multi-segmental movements of the spinal column was designed to interpret the effect of segmentation on the total measured spine motion. Also it analyzed the relative motion at three types of the spine models in drop landing. A secondary goal was to determine the intrinsic algorithmic errors of spine motion and the usefulness of such an approach as a tool to assess spinal motions. College students in the soccer team were selected the ten males with no history of spine symptoms or injuries. Each subject was given a fifteen minute adaptation period of drop landing on the 30cm height box. Inter-segmental spine motion were collected Vicon Motion Capture System (250 Hz) and synchronized with GRF data (1000 Hz). The result shows that Model III has a more increased range of motion (ROM) than Model I and Model II. And the Lagrange energy has significant difference of at E3 and E4 (p<.05). This study can be concluded that there are differences in the three models of algorithm during the phase of load absorption. Especially, Model III shows proper spine motion for the inter-segmental joint motion with the interaction effects using the seven segments. Model III shows more proper observed values about dynamic equilibrium than Model I & Model II. The findings have shown that the dynamic stability strategy of Model III toward multi-directional spinal motion supports for better function of the inter-segmental motor-control than the Model I and Model II.

• Ocean Systems Engineering
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• v.9 no.4
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• pp.369-390
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• 2019

Herein, we present numerical simulation based model to study the use of a 'Tuned Mass Damper (TMD)' - particularly spring mass systems - to control the displacements at the deck level under seismic and ice loads for an offshore jacket structure. Jacket is a fixed structure and seismic loads can cause it to vibrate in the horizontal directions. These motions can disintegrate the structure and lead to potential failures causing extensive damage including environmental hazards and risking the lives of workers on the jacket. Hence, it is important to control the motion of jacket because of earthquake and ice loads. We analyze an offshore jacket platform with a tuned mass damper under the earthquake and ice loads and explore different locations to place the TMD. Through, selected parametric variations a suitable location for the placement of TMD for the jacket structure is arrived and this implies the design applicability of the present research. The ANSYS^*TM mechanical APDL software has been used for the numerical modeling and analysis of the jacket structure. The dynamic response is obtained under dynamic seismic and ice loadings, and the model is attached with a TMD. Parameters of the TMD are studied based on the 'Principle of Absorption (PoA)' to reduce the displacement of the deck level in the jacket structure. Finally, in our results, the proper mass ratio and damping ratios are obtained for various earthquake and ice loads.

• Archives of Reconstructive Microsurgery
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• v.15 no.2
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• pp.117-122
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• 2006

The function of the thumb is critical to overall hand function. The thumb enables motions such as pinch, grip, fine manipulation and allows to circumduction and opposition. It's loss is a serious problem not only from cosmetic point of view but also functional. Therefore, we should make every effort on thumb reconstruction. Many methods of thumb reconstruction from simple osteoplasty to complex microsurgical reconstruction have been reported. We should understand merits and demerits of each method and choose proper method on case by case. When both hands are injured and there is no option but to amputate one hand and the thumb of another hand is lost, spare part flap from the thumb of the amputated hand to another hand can solve cosmetic problem, functional problem and donor morbidity. We report a case of amputated thumb which has been reconstructed with amputated ring finger of the contralateral hand using spare part flap concept.

• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.75-91
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• 2003

Evaluation of repetitiveness for hand-intensive tasks is essential to determine the level of risk for upper-extremity musculoskeletal disorders at the workplace. Many measures and methods have been introduced for repetitiveness assessment: however, our understanding of the differences among these measures and methods is lacking. The present study compared the repetitiveness measures and measurement/analysis methods to help practitioners apply the proper repetitiveness assessment methodology in the workplace. By reviewing 51 studies of repetitiveness assessment, measures and corresponding measurement/analysis methods were surveyed. Of the repetitiveness measures, two types of dimensions (frequency and time) and corresponding types of analysis scopes were identified. According to the dimensional and analysis-scope types. the repetitiveness measures were categorized and then the surveyed studies were counted for each measure. It is identified that frequency measures have used 2.7 times higher than time measures and the frequency of wrist motions has been most frequently used in repetitiveness assessment. Furthermore, the measurement methods were categorized into objective and subjective methods, and the analysis methods into statistical and spectral methods. Lastly, eight factors (accuracy, reliability. sensitivity. efficiency. ease of use. applicability. interference. and robustness) were listed to be considered in selecting the appropriate assessment methodology.

• The Journal of the Acoustical Society of Korea
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• v.22 no.1
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• pp.28-34
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• 2003

Recent researches have been focusing on jointly using lip motions (i.e. visual speech) and speech for reliable speech recognitions in noisy environments. This paper also deals with the method of combining the result of the visual speech recognizer and that of the conventional speech recognizer through putting weights on each result: the paper proposes the method of determining proper weights for each result and, in particular, the weights are autonomously determined, depending on the amounts of noise in the speech and the image quality. Simulation results show that combining the audio and visual recognition by the proposed method provides the recognition performance of 84% even in severely noisy environments. It is also shown that in the presence of blur in images, the newly proposed weighting method, which takes the blur into account as well, yields better performance than the other methods.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.203-213
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• 2004

This study investigates the seismic responses of two structures connected by a sky-bridge equipped with viscoelastic dampers (VED) at the bridge-building connections. The applicability of the method is verified first by observing RMS (root-mean-squared) responses of two-degrees-of-freedom systems subjected to white noise ground excitation. Then model structures with various number of stories are analyzed using earthquake ground motions to observe the effect of the varying size of VED on the reduction of dynamic responses. According to the analysis results, there exists a proper size of VED which minimizes the structural responses. It is also observed that the effectiveness of VED increases as the difference of natural frequencies between the two connected structures increases.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.4
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• pp.11-16
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• 2002

Flow mechanism of peristaltic motion is numerically and experimentally investigated to obtain a propulsive force in highly viscous fluid. Computing code for the analysis of the motions is developed with cell-centered unstructured grid scheme. The computed results by the developed code is compared with the experimental results which have been carried out to find out the propulsion mechanism in highly viscous fluid. The computed results shows good correlation with the experimental results and further the propulsive force can be obtained by sinusoidal motion which makes a pressure difference on waving surface. The more computation with variation of Reynolds number and parameters of motion is expected for finding a proper working range.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.115-118
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• 2015

We made phase-referencing Very Long Baseline Interferometry (VLBI) observations of Galactic 22 GHz $H_2O$ maser sources with VLBI Exploration of Radio Astrometry (VERA). We measured the parallax distances of G48.61+0.02, G48.99-0.30, G49.19-0.34, ON1, IRAS 20056+3350, IRAS 20143+3634, ON2N, and IRAS 20126+4104, which are located near the tangent point and the Solar circle. The angular velocity of the Galactic rotation at the LSR (i.e. the ratio of the Galactic constants) is derived using the measured parallax distances and proper motions of these sources. The derived value of ${\Omega}_0=28.8{\pm}1.7km\;s^{-1}kpc^{-1}$ is consistent with recent values obtained using VLBI astrometry but 10% larger than the International Astronomical Union (IAU) recommended value of $25.9km\;s^{-1}kpc^{-1}=(220km\;s^{-1})$ / (8.5 kpc).

• The KIPS Transactions:PartB
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• v.18B no.1
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• pp.11-20
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• 2011

Pictorial Structures is known as an effective method that recognizes and tracks human poses. In this paper, the upper body pose is also tracked by PS and a particle filter(PF). PF is one of dynamic programming methods. But Markov chain-based dynamic motion model which is used in dynamic programming methods such as PF, couldn't predict effectively the highly articulated upper body motions. Therefore PF often fails to track upper body pose. In this paper we propose the key pose-based proposal distribution for proper particle prediction based on the similarities between key poses and an upper body silhouette. In the experimental results we confirmed our 70.51% improved performance comparing with a conventional method.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.1-14
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• 2006

To improve maritime safety, it is very important not only to make safer design and operation but also to do proper response in case of maritime casualty. The large-scaled casualties will be caused by loss of structural strength and stability due to the progressive flooding and enlargement of damage by the effect of waves and wind. To prevent foundering and structural failure, the prediction of ship motion behavior of damaged ship in wave is necessary. This paper describes the motion behavior of damaged ship in waves through theoretical and experimental studies. A time domain theoretical model of damaged ship motions and accidental flooding, which can be applied to any type of ship or arrangement and considers the effects of flooding of compartments, has been developed. The model tests have been carried out in regular and irregular waves with different wave heights and directions in ship motion basin. Those were performed for three different damaged conditions such as engine room bottom damage, side shell damage and bow visor damage of a Ro-Ro ship. Comparison of theoretical and experimental results was performed.