• Journal of Ocean Engineering and Technology
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• v.22 no.6
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• pp.64-74
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• 2008

The flaw around a ROV (Remotely Operated Vehicle) has been numerically investigated to improve resistance performance by modifying the hull form of the ROV. For the base hull form considered in this study, the form drag rather than the friction drag is dominant to the total drag Subsequently, the surfaces on which the local pressure highly acts have been modified to produce the streamlined-shape. Based on the surface modification, seven different hull forms have been chosen as candidates for drag reduction. Among the candidates, the semi-sphericalized housing and the streamlined-bow achieved greatest drag reduction comparing with the others. Consequently, the hull form combined with the semi-sphericalized housing and the streamlined-bow gave approximately 17% drag reduction at the design velocity of 3 knots.

• Land and Housing Review
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• v.10 no.4
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• pp.51-59
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• 2019

The government is encouraging the notice of obligatory reclaimed asphalt as a result of the economic and social positioning of green growth to reduce the amount of waste resources and to solve natural resource problems by recycling continuously generated waste resources. However, it is necessary to develop application guideline for each application to apply reclaimed asphalt to the site because quality control of the reclaimed asphalt is difficult and the specifications are ambiguous as well. Therefore, in this study, the mix design, quality test, performance test, and finite element analysis about reclaimed Asphalt Pavement were conducted to develop application guideline for reclaimed hot asphalt. The mix design was carried out for the comparative general hot mix asphalt mixture, the reclaimed hot mix asphalt mixture using the additive, and the reclaimed hot mix asphalt mixture without the additive. Indirect tensile strength and tensile strength ratio tests were used to characterize the reclaimed hot mix asphalt mixture. Using the results of dynamic modulus test and FWD test for KPRP analysis and finite element analysis, the performance life was evaluated for general pavement and pavement using recycled aggregate. Finally, the life cycle cost analysis was used to compare and analyze the economics of reclaimed asphalt concrete pavement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.127-131
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• 2002

The surge protector is crucial power apparatus to guarantee the safe operation of power transmission of underground cable which can effectively restrain the overvoltage and inductive lightning stroke in power system. The surge protector is crucial power apparatus to guarantee the safe operation of power transmission of underground cable which can effectively restrain the overvoltage and inductive lightning stroke in power system. This paper described the results of a study on the performance for surge protector for underground cable. And, the performance of surge protector was evaluated through such as measurement of the reference voltage, residual voltage and impulse current etc. In results of surge protector, reference and residual voltage of ZnO element is 4.75 kV, 9.86 kV respectively. Also, In the impulse current test, thermal properties are good, despite of that polymeric housing of surge protector has thick structure. Therefore the developed surge protector is thought to apply for underground cable.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.863-868
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• 2008

In accordance with the guidelines on the balcony structure changes in December 2005, most of tenants were moving into apartment housing, expand the balcony, but some large deviation between the price construction costs set of cases, due to overuse and the cause of the dispute, and the housing law amended in 2007 due to price cap system is implemented, the cost of expansion the balcony overdose pointed out that there is set to boost the sale price has been raised. These issues in order to improve the government in January 2008, the "Note costs by the balcony expansion" suggested guidelines to protect the rights of tenants and wants to promote the settlement of the sale price cap system. This study calculated the "Note costs by the balcony expansion" window system based on double or single, high performance insulation window system of the quantitative performance analysis of each type window that purpose.

• Journal of the Korean housing association
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• v.22 no.3
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• pp.113-122
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• 2011

This study aimed to develop AI- (Artificial Intelligence) based thermal control logics and test their performance for identifying the optimal thermal control method in buildings. For this objective, a conventional Two-Position On/Off logic and two AI-based variable logics, which applied ANN (Artificial Neural Network) and ANFIS (Adaptive Neuro-Fuzzy Inference System), have developed. Performance of each logic was tested in a typical two-story residential building in U.S.A. using the computer simulation incorporating MATLAB and IBPT (International Building Physics Toolbox). In the analysis of the test results, AI-based control logic presented the advanced thermal comfort with stability compared to the conventional logic while they did not show significant energy saving effects. In conclusion, the predictive and adaptive AI-based control logics have a potential to maintain interior air temperature more comfortably, and the findings in this study could be a solid foundation for identifying the optimal thermal control method in buildings.

• Land and Housing Review
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• v.2 no.4
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• pp.509-516
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• 2011

Compared with the traditional RC system, precast stairs can save construction time, reduce the cost of concrete casting, etc. This paper focuses on an investigation of improved continuous longitudinal joint details for PC stair systems. The performance of the precast concrete stair connections subjected to displacement control cyclic loading is compared with that of the monolithic connection. The developed connection is composed of U-rods and clamp joint metals. This paper proposes precast stair connection with improved structural performance and experimentally evaluates the structural performance of the proposed joints in terms of maximum load, displacement ductiliy, strain, crack and failure modes.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.660-666
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• 2016

This paper presents performance comparison results of magneto-rheological (MR) brake in the sense of wear characteristics. To create wear circumstance, the brake is operated in 100 000 cycles by DC motor. To make wear test in same design parameters such as the radius of the housing, ferromagnetic disc and gap size, small sample of stainless are inserted in housing of MR brake. The performances of brake are compared between the initial stage (no wear) and 100 000 revolution cycles operated stage (wear). At each circumstance, torque of the brake is measured and compared by applying step current and sinusoidal control input. The controller used in this work is a simple, but effective PID controller. It is demonstrated that the wear behavior is more obvious as the operating cycle is increased in the torque control process.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.249-250
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• 2023

The objective of this study is to evaluate the airborne sound insulation performance between housing units and community facilities during the construction phase. Community facilities adjacent to housing units can lead to noise problems, hence it is necessary to minimize noise transmission during the design phase. However, flanking noise transmitted through gaps of structures, windows, pipes, and other openings may result in substandard sound insulation performance falling below the design standards. Therefore, It is crucial to measure airborne sound insulation in the field during the construction phase. The measurement was conducted using the survey method for the field measurement of the airborne sound insulation in accordance with KS F ISO 10052:2021. Although the noise standards caused by community facilities in apartment complexes are not specified in current laws and regulations, desired noise level was set based on international guidelines for indoor noise. First, the level of noise generated in community facilities was estimated, and then the sound insulation performance was evaluated to determine whether the desired noise level was achieved.

• Land and Housing Review
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• v.15 no.3
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• pp.189-198
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• 2024

This study analyzes the thermal performance of insulating concrete based on material combinations aimed at carbon reduction. The study compares the thermal and structural properties of insulating concrete enhanced with perlite and EPS (Expanded Polystyrene) beads to conventional concrete, with a focus on the impact of insulation properties on thermal conductivity. The results indicate that the content of EPS beads is critical to the insulating performance, and increased moisture absorption significantly reduces the energy efficiency of the insulating concrete. These findings provide valuable insights for the design and application of insulating concrete to enhance energy efficiency and reduce carbon emissions. This study offers guidance for further developing insulating concrete as a carbon-reducing building material.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.355-358
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• 2002

Since the 1960s, though there were brisk supply in apartment housing, there were no preparation in standard for to extend the life(durability) of apartment housing by maintaining the $social{\cdot}physical$ aspect of apartment housing, and in standard maintenance system. So problem such as facilities safety and residence environment has occurred. Like the condition written above, efficient usage of housing resource by the maintenance of apartment housings in a state of great urgency. In service aspect of apartment housing, establishment of accurate long term repair plan and estimate of repair appropriation fund can prevent housing's fast-deterioration. But to the performers of the maintenance, like house managers and the tenants at the subject building has little awareness of necessity in establishment of accurate long term repair plan and accumulation of repair appropriation fund. Unestablishment of long term repair plan arises problem such as approval of repair appropriation fund's unreasonable accumulation. Hence, for the utmost performance of apartment housing and to extend the economic life of a building, the method of establishment of long term repair plan and estimate of repair appropriation fund on reliable basis is to be proposed.