• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.179-186
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• 2004

Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Pohang Old Harbor and Pohang New Port, etc. due to construction of New Port in Youngil Bay. This type of trial might be a milestone for port development in macroscale, where the induced impact analysis in the existing port due to the developemnt could be easily neglected.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.793-804
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• 2006

Various PSC and steel-concrete composite railway bridges are being developed for short-medium spans with structural and economic efficiency. According to the design concept, the prestressed composite girder bridge has the advantages of being lightweight and having low girder depth, with the capacity for long spans. However, the dynamic behavior under a passing train is one of the critical issues concerning these railway bridges designed with more flexibility. Therefore, it is very important to evaluate the modal parameters before performing dynamic analyses. In this paper, real-scale prestressed composite girders were fabricated as a test model and modal testing was carried out to evaluate modal parameters including natural frequency and modal damping ratio. During the modal testing, a digitally controlled vibration exciter as well as an impact hammer was applied to obtain frequency-response functions, and the modal parameters were also evaluated after the fracture of test models. With application of reliable properties from modal tests, the estimation of dynamic performances of prestressed composite girder railway bridges can be obtained from various parametric studies on dynamic behavior under the passage of a moving train.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.421-428
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• 2004

Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Pohang Old Harbor and Pohang New Port, etc. due to construction of New Port in Youngil Bay. This type of trial might be a milestone for port development in macroscale, where the induced impact analysis in the existing port due to the development could be easily neglected.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.285-295
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• 2020

In the case of small observation towers located at sea, it is necessary to confirm the change in dynamic characteristics due to the influence of environmental loads. In this study, the dynamic characteristics were analyzed and the numerical analysis model was designed through field dynamic response measurement on the Mangyeong Offshore Observation Tower (Mangyeong Tower) located near the Saemangeum Embankment. As a result of the measurement, the natural frequency was found to increase slowly as the tide level is lowered. In addition, it was confirmed that the same mode has two frequencies, which was judged to be a phenomenon in which the natural frequency was partially increased when the pile and the ground contacted by scouring. For numerical analysis, the upper mass, artificial fixity point, scour depth and fluid influences are reflected in the structural characteristics of the Mangyeong Tower. In addition, the model updating from the estimated natural frequency and pattern search algorithm was performed. From the model updating, it is expected that it can be applied to future studies on stability of Mangyeong Tower.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.56-65
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• 2005

A dynamic analysis method that freezes a time domain by discretization and solves the spatial propagation equation has a unique feature that provides a degree of freedom on spatial domain compared with the space discretization or space-time discretization finite element method. Using this feature, the time finite element analysis can be effectively applied to optimize the spatial characteristics of distributed type actuators. In this research, the time domain finite element method was used to discretize the model. A state variable vector was used in the discretization to include arbitrary initial conditions. A performance index was proposed on spatial domain to consider both potential and vibrational energy, so that the resulting shape of the distributed actuator was optimized for dynamic control of the structure. It is assumed that the structure satisfies the final rest condition using the realizable control scheme although the initial disturbance can affect the system response. Both equations on states and costates were derived based on the selected performance index and structural model. Ricatti matrix differential equations on state and costate variables were derived by the reconfiguration of the sub-matrices and application of time/space boundary conditions, and finally optimal actuator distribution was obtained. Numerical simulation results validated the proposed actuator shape optimization scheme.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.1-7
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• 2005

Methylophaga aminosulfidovorans SK1 (KCTC 10323 BP) can utilize trimethylamine as a sole carbon, nitrogen, and energy source. The bacterial flavin-containing monooxygenase (bFMO) gene was identified in the strain and the recombinant enzyme expressed in E. coli oxidized trimethylamine. To study the function and regulation of the bfmo, over 8,000 nucleotide sequences of the neighboring regions including the bfmo were determined. Three open reading frames proceeding to the bfmo gene encoded analogues to highly conserved nitrate/nitrite sensing two-component system regulators and a methyl accepting protein. Two small open reading frames just downstream of the bfmo gene showed no similar proteins of known functions but the sequences were conserved among other bacteria. Reverse transcription-polymerase chain reaction analysis showed that the six putative genes consisted of three transcription units. The three regulatory genes located upstream of the bfmo gene formed two separate transcription units. The bfmo and the two downstream genes were transcribed from a single promoter.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.285-292
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• 2012

Fixed connection is generally used for beam and column connections of concrete structures, but significant damages at the connection due to severe earthquakes have been reported. In order to reduce damages of the connection and improve seismic performance of the connection, several innovative connections have been suggested. One newly proposed connection type allows a rotation of the connection for applications in rotating or rocking beams, columns, and shear walls. Such structural elements would provide a nonlinear lateral force-displacement response since their contact depth developed during rotation is gradually reduced and the stress across the sections of the elements is non-linearly distributed around a contact area, which is called an elastic hinge region in the present study. The purpose of the present study is to define the elastic hinge region or length for the rocking columns, through investigating the cross-sectional stress distribution during their lateral behavior. Performing a finite element analysis (FEA), several parameters are considered including axial load levels (5% and 10% of nominal strength), different boundary conditions (confined-ends and cantilever types), and slenderness ratios (length/depth = 5, 7, 10). The FEA results showed that the elastic hinge length does not directly depend on the parameters considered, but it is governed by a contact depth only. The elastic hinge length started to develop after an opening state and increased non-linearly until a rocking point(pre-rocking). However, the length did not increase any more after the rocking point (post-rocking) and remained as a constant value. Half space model predicting the elastic hinge length is adapted and the results are compared with the numerical results.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.61-69
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• 2007

The main purpose of this study is to provide a basic information for the seismic capacity evaluation and the seismic design of low-rise reinforced concrete (RC) shear wall buildings, which are comprised of a pilotis in the first story. In this study, relationships between strengths and ductilities of each story of RC buildings with pilotis are investigated based on the nonlinear seismic response analysis. The characteristics of low-rise RC buildings with pilotis are assumed as the double degree of freedom structural systems. In order to simulate these systems, the pilotis is idealized as a degrading trilinear hysteretic model that fails in flexure and the upper story of shear wall system is idealized as a origin-oriented hysteretic model that fails in shear, respectively. Stiffness properties of both models are varied in terms of story shear coefficients and structures are subjected to various ground motion components. By analyzing these systems, interaction curves of required strengths for various levels of ductility factors are finally derived for practical purposes. The result indicates that the required strength levels derived can be used as a basic information for seismic evaluation and design criteria of low-rise reinforced concrete shear wall buildings having pilotis structure.

• Korean Journal of Social Welfare
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• v.61 no.1
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• pp.5-32
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• 2009

The purpose of this study is to examine the effects of organizational culture types (rational culture, developmental culture, group culture, and hierarchical culture) on Community-Centered Social Inclusion Orientation(COSI) among social service organizations for people with disabilities. More specifically, this study developed and empirically tested two theoretical models where each of organizational culture types were hypothesized to affect COSI either directly or indirectly through market orientation. For data collection, self-administered type questionnaires were mailed to 416 social service organizations for people with disabilities across the nation and 293 responded (response rate: 70.4%) from June 1 to September 22, 2006. For analysis, however, only 263 respondents were used, excluding Independent living centers due to their small size and short history. Structural Equation Modeling was employed for analysis and Full Information Maximum Likelihood was used for estimation. Findings indicated that market orientation had a significant effect on COSI. In addition, developmental culture and hierarchical culture were found to affect COSI directly while rational culture and group culture were found to affect COSI indirectly through market orientation. These findings imply that market orientation needs to be emphasized as a strategy in order to enhance social inclusion orientation for those organizations. Given that all the four types of organizational culture have direct or indirect impacts on COSI, those organizations are also advised to develop the four types of organizational culture harmoniously rather than one single type of organizational culture.

• Journal of Life Science
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• v.27 no.12
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• pp.1415-1420
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• 2017

The metallothionein (MT) gene (IbMT3) was selected from an EST library of suspension-cultured sweet potato cells. The MT gene, which is one of abundant ESTs in the library, is involved in stress regulation of cells and tissues. A full-length IbMT3 cDNA was obtained and analysis of its nucleotide sequence revealed that IbMT3 encoded a type 3 MT protein, based on its structural characteristics. The function of type 3 MT in plants is not yet known. Northern blot analysis showed stronger expression of IbMT3 in suspension-cultured cells than in sweet potato plant leaves. Since cell culture is known to impose a state of oxidative stress on cells, sweet potato plants were subjected to oxidative stress to investigate the transcriptional regulation of IbMT3. When the herbicide methyl viologen (MV) was administered for 6, 12, and 24 hr, IbMT3 transcription rapidly increased at 6 hr and then decreased. A cold treatment at $15^{\circ}C$ for 24 and 48 hr resulted in a gradual increase in IbMT3 expression. These findings indicate that IbMT3 expression is regulated in response to environmental and oxidative stress. IbMT3 isoform is expected to have antioxidant effects in sweet potato plants and may play an important role in cellular adaptation to oxidative stress.