• Journal of Industrial Technology
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• v.18
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• pp.117-124
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• 1998

In recently, according to increase the construction rate of steel bridge, it is necessary to develop the high strength, high toughness steel. Thus, this study show to evaluate the fatigue characteristic of SWS 570 B first used within a country. With the weld-joined compact tension specimens compared with each other, that is, transverse and lengthwise about the crack propagation, high and low in the input heat level, the fatigue test were performed. The log-log curves between the fatigue crack propagation rate da/dN and the transition range of the stress intensity factor ${\Delta}K$ ahead the crack tip were drawed, with these data. By using this curve, we obtained C and m which is material constant from Paris-Erdogan power law. The obtained results from this study indicate that fatigue crack growth rate of SWS 570 B is not influenced by softening effect which occurs in the HAZ(heat-affected zone) when high and low heat input weld is carried out. Softening effects, which affect fatigue properties, are shown that it is not affected to the fatigue growth rates significantly.

• Water for future
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• v.27 no.3
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• pp.145-158
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• 1994

The linear reservoir rainfall-runoff system was developed as a rainfall-runoff event simulation model. It was achieved from large modification of runoff function method. There are six parameters in the model. Hydrologic losses consist of some quantity of initial loss and some ratio of rainfall intensity followed by initial loss. The model has analytical routing equations. Hooke and Jeeves algorithm was used to model calibration. Parameters were estimated for flood events from '84 to '89 at Seomyeon and Munmak stream gauges, and the trends of major parameters were analyzed. Using the trends, verifications were performed for '90 flood event. Because antecedent fainfalls affect initial loss, future researches are required on such effects. The estimation method of major parameters should also be studied for real-time forecasting.

• Journal of KIBIM
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• v.6 no.3
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• pp.42-48
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• 2016

Structural members are designed to maintain the load-carrying capacity as well as structural strength, and the structural serviceability such as the deflection, cracks, and vibration to give the occupants uncomfortable environment should be checked. Recently, the importance of the vibration has been issued since the Techno Mart accident due to vibration resonance. This study provides a passive vibration control system using the repulsion force of magnets to reduce dynamic vibrations. The systems is devised by importing the constraint condition by a hinge to operate magnets installed at two adjacent locations. The effectiveness of the proposed system is investigated by the vibration control test of a steel beam with and without the control system. It is illustrated in the test that the system is activated by the control forces executed by the magnets and can be utilized in reducing the dynamic responses. The system can be applied to pedestrian bridge and traffic bridge. The applicability is expected in the future by optimizing the factors to affect the dynamic responses like the intensity, mass, locations of magnets.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.153-156
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• 2008

Comparative analysis of forest fire danger rating on the forest characteristics of thinning area and non-thinning area on forest fire burnt area was studied in this work. To investigate the effect of thinning slash in forest fire, Gangneung-si Wangsan-myeon, Ulgin-gun Wonnam-Myeon, Samchok-si Gagok-Myeon, in which forest fire broke out, were selected. As a result that investigated forest fire danger ratio between thinning slash and non-thinning slash, leeward scorching ratio(36%), crown damage ratio(29%), mortality of branch at the former are higher than those at the latter, leeward scorching ratio of tree, where thinning slash is around, is 10%-20% higher than that of independent tree. So I estimate that thinning slash has a some effect on the intensity of forest fire. And the result to investigate damage of forest fire according to tree species shows that leeward scorching ratio of conifer is 5% higher than that of non-conifer, and mortality of branch of the former is 19% higher than that of the latter. It is considered that forest fire may affect directly to a tree trunk if it diffuse to piled thinning tree because there was no space between thinning trees and trees. Furthermore, it was found that re-ignition had a chance to occur due to lots of piled thinning trees.

• Journal of Animal Science and Technology
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• v.57 no.2
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• pp.6.1-6.5
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• 2015

The objectives of this study were to study the effects of different levels of dietary copper on organ indexes, tissular Cu, Zn and Fe deposition and fur quality of mink in the growing-furring periods. One hundred and five standard dark male mink were randomly assigned to seven groups with the following dietary treatments: basal diet with no supplemental Cu (Control); basal diet supplemented with either 6, 12, 24, 48, 96 and 192 mg/kg Cu from copper sulphate, respectively. The colour intensity scores displayed a linear trend (P = 0.057). The spleen Cu concentrations responded in a linear (P < 0.05) fashion with increasing level of Cu, but copper supplementation did not affect speen concentrations of Fe or Zn. Supplemental dose of Cu linearly increased (P < 0.05) liver Cu and Fe concentrations but did not alter (P > 0.10) liver Zn. Our results indicate that Cu plays an important role in the pigmentation in growing-furring mink, and supplemental dietary Cu in growing-furring mink improve hair colour, and copper has limited effects on liver mineral deposition.

• Journal of Radiation Industry
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• v.10 no.4
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• pp.193-198
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• 2016

Perfusion magnetic resonance image of biological mechanism are independent of magnetic field strength in hyper acute ischemic stroke. 3.0 T magnetic field, however, does affect the SNRs (signal to noise ratio) and artifacts of PMRI (perfusion magnetic resonance image), which basically will influence the quantitative of PMRI. In this study, the effects of field strength on PMRI are analyzed. The effects of the diseases also are discussed. PMRI in WM(white matter), GM (gray matter), hyper acute ischemic stroke were companied with 1.5 T and 3.0 T on SNR. PMRI also was compared to the SI difference after setting ROI(region of interest) in left and right side of the brain. In conclusion, the SNRs and SI of the 3.0 T PMRI showed higher than those at 1.5 T. In summary, PMRI studies at 3.0 T is provided significantly improved perfusion evaluation when comparing with 1.5 T.

• Journal of Information Technology Applications and Management
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• v.26 no.1
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• pp.77-93
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• 2019

Recently, office workers are increasingly aware of the right to disconnect because of the pressure from strong connections with Internet messengers. In this study, we examined the reason why the perception of the right to disconnect increases and how to deal with it. This research model is that smart working and psychological attachment from work affect right to disconnect, and that open communication and gender moderate the intensity of these effects. To verify this research model, survey questionnaires were distributed to workers in smart working environments, and 400 data were collected and analyzed using Smart-PLS. As results of data analysis, it was verified that smart working and psychological attachment from work had a significant influence on right to disconnect, that open communication group had a lesser effect of psychological attachment from work on right to disconnect than closed communication group, and that women had a lesser effect of psychological attachment from work on right to disconnect than men. Organizations need to maintain a desirable level of right to disconnect in order to improve the quality of working life. But, if it is impossible, They need to change the way of communication more openly so as to absorb the burden of strong connection by Internet. And they need to perform task assignment or stress relief policy reflecting gender characteristics.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.561-573
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• 2021

Knowing how to build and maintain consumer trust is crucial for e-commerce. Despite the number of empirical studies that have explored the factors that influence consumer trust, none of them considers the relative importance of different antecedents and how they interact to influence consumer trust. Therefore, based on the integrated Decision Making Trial and Evaluation Laboratory (DEMATEL) and Interpretive Structural Modeling (ISM) approaches, we establish a hierarchical structural model, which not only demonstrates the intensity of the relationships but also identifies the interdependence among the drivers of consumer trust in E-commerce. The findings confirm that propensity to trust is the most important determinant of consumer trust. The brand-related factors and platform-related factors are prominent in the process of building trust as they influence consumer trust indirectly through propensity to trust. Geographic location, demographic variables, and high security are identified as the root causes that affect consumer trust through other trust antecedents. Furthermore, the findings of this study offer valuable insights into an important element of e-commerce and provide a useful platform for future research. More represented samples and factors are encouraged for further research to ensure research fairness and minimize consumer distrust and uncertainty.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.175-184
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• 2021

Objective: Fatigue can decrease both quality of life and work efficiency. Ginseng is one of the most popular herbal treatments for improving personal health, with applications in treating fatigue. However, the exact mechanisms of anti-fatigue effects are still unclear. Thus, we investigated the effect of red ginseng powder (RGP) on exercise capacity and peripheral fatigue using both behavioral and molecular experiments in mice. Design: Four-groups behavioral and molecular experiment. Methods: Male 6-weeks-old ICR mice were treated with distilled water, 100, and 200 mg/kg RGP for 5 days via oral administration. The exercise capacity of each animal group was measured by locomotor activity, rota-rod, hanging wire, and cold swimming tests. Additionally, after performing the treadmill to induce fatigue, lactate expression and molecular experiments were investigated using mice gastrocnemius. Results: Mice treated with RGP exhibited increased exercise capacity in the behavioral tests. Additionally, RGP induced a dose-dependent decrease in lactate levels after high-intensity exercise, and Monocarboxylate transporter (MCT) 4 expression increased in groups treated with RGP. However, there was no significant change in MCT1. Conclusions: These results suggest that RGP exerts several anti-fatigue properties by lower lactate and improved exercise capacity. Increased MCT4 expression may also affect lactate transport. Thus, this study suggests that the anti-fatigue properties of RGP might be associated with MCT4 activity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.7
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• pp.8-14
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• 2021

Even welds that have passed non-destructive testing in the case of brittle crack arrest steel materials will actually have very fine weld defects. Based on studies showing that these defects adversely affect the structure if subjected to a certain period of load, the following conclusions were obtained by conducting CTOD tests on welding joints of high-strength BCA materials, structures comprising the upper decks of a large container vessel. First of all, the fatigue pre-cracking in the weld metal and heat affected areas was tested and the behavior was identified. Both parts of the welding joint are allowable range for the class regulations. In addition, CTOD results showed that the CTOD value in the heat affected area was more than 0.5 times higher than in the weld metal area.