• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.607-614
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• 2015

This study evaluated the flexural performance of steel and PP fiber reinfroced shotcrete using round panel test according to ASTM that can consider the actual stress of fiber reinforced shotcrete in tunnel and under ground structures. The results of round panel test are converted to the square panel test results according to the EFNARC. The energy absorptions of each fiber reinforced shotcrete were classified according to the EFNARC toughness classification. Test results show that the PP fiber reinforced shotcrete has better flexural performance compared with the steel fiber reinforced shotcrete.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.352-356
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• 2006

As a basic study to develop heating panel, the purpose of this study was to know possibility as a floor heating panel. We investigated working conditions and performance of pulsating heat pipe. Tests were conducted under the next conditions; Working fluid were R-22 and R-134a, charging ratio 40% and 50%, temperature of inlet water $60^{\circ}C$ and $70^{\circ}C$, flow rates $1{\sim}3kg/min$. The experimental results indicate that the pulsating heat pipe charged 50% showed better performance than 40%, R-22 is more suited to the working fluid than R-134a, and it has a possibility which can be applied to floor heating panel using a pulsating heat pipe.

• Journal of Aerospace System Engineering
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• v.12 no.6
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• pp.50-57
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• 2018

This paper proposes the use of supports as passive vibration absorber to a composite solar panel for a high-agility satellite. We further defined the dynamic model of the composite solar panel with the help of the Ritz method and verified vibration suppression performance of the support by performing vibration analysis. Finally, this research ensures optimal design of the composite solar panel with the support for maximizing vibration suppression performance in limited mass. The proposed results of the optimal design can be applied in actual structural design of satellites.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.951-955
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• 2007

Recently, drywall's demand is increasing by interest about spread of remodeling house and separated wall structure. This research evaluated panel's SRI and found out panel properties using material of small size. Conclusion of this research is as following. First, we confirmed the effectiveness of small-scale material. Measuring results appeared equally about 400 ${\sim}$ 500 Hz that is fc frequency. Second,, it is no big difference in SRI that use CRC or magnesium board that is used for protection of panel surface. Third, it is compared SRI by used junction to make wall that become disjointing assembly. By the result, sealed wall secures resemblant SRI performance almost with normal wall. Therefore, using joint materials and sealing junction became wall that is detached with high SRI.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.56-60
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• 2007

Nowadays shear wall structural system is gradually changing to framed structure. For this reason, lightweight panel is increasingly being used as separating walls. One of design methods to obtain high transmission loss is double panel. To predict the acoustic performance of double panel, prediction of transmission loss of single panel must be performed, previously. In this study, the predicted values for four single panels were compared with the measured values. The result shows the arithmetical average deviations(100Hz to 3150Hz) between the predicted and measured transmission loss were in range between 1.1dB and 3.9dB. The predicted values were generally lower than measured values above critical frequency. The single-number quantities, $R_W+C$, were predicted in range between 36dB to 38dB, and the differences of single-number quantities between the predicted and measured value were within 1dB.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.544-546
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• 2008

An improved dual-path energy recovery circuit (ERC) using a current source and a voltage source for plasma display panel (PDP) is proposed. The proposed ERC uses the voltage source to charge a panel and the current source to discharge the panel. Thus, the proposed circuit can make the panel charge to $V_S$ and discharge to 0V, fully and it is possible to achieve zero voltage switching (ZVS) of all switches in H-bridge inverter and zero current switching (ZCS) of all switches in the ERC. Moreover, it has less conduction and switching loss in ERC devices by the dual energy recovery paths for charging and discharging the panel. Furthermore, it has features of canceling the gas discharge current, high performance and the low cost ERC components. The operation principle and features of the proposed ERC are presented in detail and verified with 42-inch SD PDP.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.97-100
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• 2005

Precise prediction of resonance frequency has been the subject of numerous papers related to Helmholtz resonator design because of its high performance at the frequency. The resonance frequency is dependent upon not only the internal dimensions of resonator but also the external boundary conditions such as the existence of other resonators in Helmholtz resonator array panel. However, the latter effect, which changes the external end correction of resonator, has not been well studied. We propose a formula to calculate the radiation impedance (or external end correction) of Helmhoitz resonator array panel. Any distance between adjacent resonators and any angle of Incidence can be allowed in the method. Numerical examples show how and how much the distance affects the resonance frequency of the panel. It is also found that the maximum absorption of the panel varies with the resonator arrangement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.28-29
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• 2015

Although there are many applications with gypsum board because of its economical and construction advantages, four-layer construction technique, (hollow area between two-layer panel sets) is the general case to achieve the insulation, and resistance of horizontally applied force. Since this construction method has many problems such as complicate construction steps and increased cost, it is needed that the two-layer panel for improved construction and economical advantage for lightweight pane: thick panel with favorable performances. Therefore, in this research, based on the ALC panel with 10 to 30mm depth, feasibility of the paper reinforced panel as a lightweight wall material. As a result, favorable performance with increased flexural strength were achieved with paper reinforcement.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.4
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• pp.15-25
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• 2005

As implied by the terms of IT productivity Paradox, measuring the Information technology contribution to economic performance has been one of the challenging issues to both policy makers and business professionals. As such, diverse attempts with sophisticate analyses have been reported in the literature to analyze the effect of IT contributions. In this paper, we follow Growth Accounting Method to measure the IT contribution effect to manufacturing firm's economic performance in Korea. Various regression methods and statistical analyses are applied with fourteen years of industry Panel data. Using the Cobb-Douglas function, time lag analysis is made to understand IT effect to economic growth. Instead of capturing data from individual firm, industry level data from the National Statistics Bureau is used for IT capital, non-IT capital, and so on. Statistical analysis following the panel unit test and Panel co-integration test was performed to reveal the exact effect of IT contribution to economic performance. Empirical testing results for non-stationary nature of IT investment effect are reported as well as IT contribution to manufacturing industry's economic performance.

• Earthquakes and Structures
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• v.27 no.1
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• pp.69-82
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• 2024

In the conventional seismic design approach for a bridge pier, the function of the stopper, and shear key are to serve as mechanisms for unseating prevention devices that retain and transmit the lateral load to the pier under strong earthquakes. This frequently inflicts immense shear forces and bending moments concentrated at the plastic hinge zone. In this study, a shear panel damper plus gap (SPDG) is proposed as a low-cost alternative with high energy dissipation capacity to improve the seismic performance of the pier. Therefore, this study aimed to investigate the seismic performance of the pre-stressed concrete I girder (PCI-girder) bridge equipped with SPDG. The bridge structure was analyzed using nonlinear time history analysis with seven-scaled ground motion records using the guidelines of ASCE 7-10 standard. Consequently, the implementation of SPDG technology on the bridge system yielded a notable decrease in maximum displacement by 41.49% and a reduction in earthquake input energy by 51.05% in comparison to the traditional system. This indicates that the presence of SPDG was able to enhance the seismic performance of the existing conventional bridge structure, enabling an improvement from a collapse prevention (CP) level to an immediate occupancy (IO).