• Journal of Animal Science and Technology
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• v.48 no.4
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• pp.623-636
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• 2006

6,161 research articles in the Life Sciences field published in domestic journals in 2004 were evaluated using bibliometrics. The total number of authors was 29,759 and the average number of authors per article was 4.8. 63.4 percent of the articles in domestic journals had more than 4 co-authors. However, this is about 25.5 percent points lower than that of Life Sciences articles in the CELL/NATURE/SCIENCE. The co-authored articles in the domestic journals mainly consist of university - university collaboration (19.9 percent). On the other hand, the co-authored articles in the CELL/NATURE/SCIENCE mainly consist of university-research institution collaboration (48.2 percent).

• Journal of the Korean GEO-environmental Society
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• v.19 no.1
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• pp.31-36
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• 2018

Recently, as the building construction works have been activated, the environment in which the excavation work is proceeding in parallel with the existing structure and the adjacent excavation work is increasing. However, there is not a lot of research on this. In this study, numerical analysis was carried out for interaction analysis between former excavation construction and follow-up excavation on two excavation retaining structures in parallel with excavation. As a result of numerical analysis, if the supporting load of strut is not considered, it was analyzed that the displacement distribution in the structure can be underestimated and acting stress of strut is overestimated. It was analyzed that the support stress causes by the former excavation should be considered in order to simulate the actual behavior characteristic.

• Special Issue of the Society of Naval Architects of Korea
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• 2006.09a
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• pp.112-121
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• 2006

The vertical displacement of a ship on the basis of the sea level is an important parameter for its stability and control. To indicate the displacement on operating conditions, "draft marks" are carved on the hull of the ship in various ways. One of the methods is welding. The position, shape and size of the marks are specified on the shipbuilding rules by classification societies to be checked by shipbuilders. In most cases, high-skilled workers do the welding along the drawing for the marks and welding bead becomes the marks. But the inaccuracies due to human errors and high labor cost increase the needs for automating the work process of the draft marks. In the preceding work, an indoor robot was developed for automatic marking system on flat surfaces and the work proved that the robot welding was more effective and accurate than manual welding. However, many parts of the hull structure constructed at the outdoor are cowed shapes, which is beyond the capability of the robot developed for the indoor works on the flat surface. The marking on the curved steel surface requiring the 25m elevations is one of the main challenges to the conventional robots. In the present paper, the robot capable of climbing vertical curved steel surfaces and performing the welding at the marked position by effectively solving the problems mentioned earlier is presented.

• Special Issue of the Society of Naval Architects of Korea
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• 2006.09a
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• pp.46-52
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• 2006

For ships, heat resistant coating is applied on the aluminized steel pipe systems dealing with high temperature steam over $200^{\circ}C$. The coatings on these steam pipes should retain both heat resistance and anti-corrosion properties to provide long-term resistance against coating defects (rust, delamination and crack) under the harsh outdoor environment including repeated seawater wetting and condensation. Thus, it is important to improve the coating qualities and to reduce maintenance works for these steam pipe systems. In this study, five different commercial heat resistant coatings (A, B, C, D, E) were selected for evaluation. Various physical properties of these coatings were evaluated on the coatings applied on the aluminized steam pipes. FT-IR analysis was also employed to identify the factors contributing the degree of heat resistance and durability of each coating material. The results indicated that the heat resistance capacity of coatings increased with the increase of silicon content as well as the decrease of substituent content. Both products C and D showed the best coating qualifies, which can be standard coating systems for future steam pipe areas.

• Journal of Hydrogen and New Energy
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• v.24 no.6
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• pp.524-534
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• 2013

Gasoline direct injection(GDI) engine has a high thermal efficiency, but it has a problem to increase carbon emissions such as soot and $CO_x$. In this study, the objective is to analyze numerically a problem for adding the hydrogen during the intake stroke so as to reduce the injected amount of gasoline in GDI engines. For selection of the base model, the cylinder pressure of simulation is matched to experimental data. The numerical analysis are carried out by a CFD model with the hydrogen addition of 2%, 3% and 4% on the volume basis. In the case of 3% hydrogen addition, the injected gasoline amount is only changed to match the maximum pressure of simulation to that of the base model for additional study. It is found that the combustion temperature and pressure increase with the hydrogen addition. And NO emission also increases because of the higher combustion temperature. $CO_x$ emissions, however, are reduced due to the decrease of injected gasoline amount. Also, as the injected gasoline amount is reduced for the same hydrogen addition ratio, the gross indicated work is no significant, But NO and $CO_x$ emissions are considerably decreased. On the order hand, $CO_x$ emissions of two cases are more decreased and their gross indicated works are higher obtained than those of the base model.

• Land and Housing Review
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• v.3 no.4
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• pp.399-406
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• 2012

One-third of total energy and 50% of $CO_2$ emissions arise from construction phase. Because of this global amount of energy consumption and $CO_2$ emission, we must do our best to solve this problem. But our existing ways of meeting this problem has focused on the energy consumption saving of the construction and dwelling stage. On the other hand, we has been treated too lightly for handling the $CO_2$ emissions problem during the maintenance management and the demolition process so far,. In this paper, we quantitatively predicted and evaluated the environmental load in each construction step during all life cycle. And, we developed the environmental load assessment program for each construction step. And we proposed the reliable decision support model for objective and reliable environmental load assessment and reduction. This result must help the development of construction technology and low carbon & green growth.

• Korean Journal of Materials Research
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• v.24 no.8
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• pp.407-412
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• 2014

Currently, diopside ($MgCaSi_2O_6$) crystal glaze is used frequently for pottery works or in earthen wares, though the process is not straightforward. However, to create and control the positions and sizes of the crystals in desired amounts when making pottery is difficult. To solve this problem, a diopside crystal seed was created at a temperature of $1450^{\circ}C$. After planting this seed in the glaze, a glaze combination and firing process which allows a user to create crystals with the desired position and at the desired size were established. In addition, in order to investigate the creation process of the crystals, the growth patterns of the crystals were observed and examined using Raman spectrography and XRD and SEM analyses. As a result, the optimum synthesis condition of the diopside seed was created by mixing 1 mole of $CaCo_3$, 0.2 mole of $(MgCo_3)_4(MgCoH)_2{\cdot}5H_2O$ and 2 moles of $SiO_2$ and then applying a firing process to the mixture at $1,450^{\circ}C$ for 30 minutes. The optimum glaze content of the seed was 70 % feldspar, 20 % limestone and 10 % $MgCo_3$. For the firing process, it was confirmed that the size of crystal is larger with a longer firing time at $1100^{\circ}C$ by completing a two-hour process at $1280^{\circ}C$. In addition, the diopside crystal has columnar structure and is less than $1{\mu}m$ in size.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.710-718
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• 2008

This paper presents a simple and fast approach to plan the arrangement of supports and to do a ship docking analysis. The unpredicted structural damages often happen from a docking works as the size of ships are getting larger and larger. In docking a ship, excessive reaction forces from supports are primary causes of the structural damage. The grillage analysis method is employed to simply calculate only the reaction forces at supports. The grillage modeling strategies are proposed to improve the accuracy. In this paper, the results obtained by the proposed approach are compared with those of the current whole-ship FEA for typical types of ships. Comparison shows that the results from the present grillage approaches are reasonably in a good agreement with the 3-D full F.E one. Finally, an integrated program developed for the ship docking analysis is described.

• International Journal of Fluid Machinery and Systems
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• v.3 no.4
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• pp.315-323
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• 2010

This work investigates the influence of water compressibility on pressure pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX. A pipe flow example with harmonic velocity excitation at the inlet plane is simulated using different grid densities and time step sizes. Results are compared with a validated code for hydraulic networks (SIMSEN). Subsequently, the solution procedure is applied to a simplified 2.5-dimensional pump-turbine configuration in prototype with different speeds of sound as well as in model scale with an adapted speed of sound. Pressure fluctuations are compared with numerical and experimental data based on prototype scale. The good agreement indicates that the scaling of acoustic effects with an adapted speed of sound works well. With respect to pressure fluctuation amplitudes along the centerline of runner channels, incompressible solutions exhibit a linear decrease while compressible solutions exhibit sinusoidal distributions with maximum values at half the channel length, coinciding with analytical solutions of one-dimensional acoustics. Furthermore, in compressible simulation the amplification of pressure fluctuations is observed from the inlet of stay vane channels to the spiral case wall. Finally, the procedure is applied to a three-dimensional pump configuration in model scale with adapted speed of sound. Normalized Pressure fluctuations are compared with results from prototype measurements. Compared to incompressible computations, compressible simulations provide similar pressure fluctuations in vaneless space, but pressure fluctuations in spiral case and penstock may be much higher.

• Informatization Policy
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• v.29 no.1
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• pp.3-23
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• 2022

As a form of online co-production, government crowdsourcing platforms have received growing attention from scholars and practitioners as a means of enhancing government-citizen co-production. This research aims (1) to introduce government leaders and managers to recent empirical research examining real-world cases of government crowdsourcing from different countries, (2) to systematically organize, analyze, and discuss the findings and implications of recent government crowdsourcing empirical studies, and (3) to provide government practitioners with evidence-based insights that could encourage informed decisions about how they design, implement, and evaluate government crowdsourcing platforms effectively and inclusively. Literature review is limited primarily to empirical works that rigorously examined real-world cases of government crowdsourcing. By focusing on a review of empirical research on crowdsourcing co-design and crowdsourcing design/government delivery platforms, this study discusses the key findings systematically and offers some insights and implications for leaders and managers seeking effective and inclusive design and implementation of government crowdsourcing platforms.