• International Journal of High-Rise Buildings
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• v.3 no.4
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• pp.285-296
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• 2014

The objective of optimization is to present a design process that minimizes the total material consumption while satisfying current codes and specifications. In the research an optimization formulation for RC shear wall structures is proposed. And based on conceptual design methodology, an optimization process is investigated. Then optimal design techniques and specific explanations are introduced for residential buildings with shear wall structure, especially for that with a rectangular layout. An example of 30-story building is presented to illustrate the effectiveness of the proposed optimal design process. Furthermore, the influence of aspect ratio on the concrete consumption and the steel consumption of the superstructure are analyzed for this typical RC shear wall structure; and their relations are obtained by regressive analysis. Finally, the optimal material consumption is suggested for the residential building with RC shear wall structure and with rectangular layout. The relation and the data suggested can be used for guiding the design of similar RC shear wall structures.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.75-81
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• 2015

At the end of the 19th century, Edison's DC power system and Tesla's AC power system was debated in power market. Finally, AC system became the primary system of the power market because both step-up and step-down of voltage by using transformer and long-distance power transmission are easily possible. However, nowadays the power market takes some action for introducing DC system. Both domestic and foreign researchers are conducting the study on the DC system as well. Some researchers have conducted the studies on power quality and economic evaluation of the DC distribution system but DC distribution system is still controversial in terms of the effectiveness and reliability. In this paper, we calculate the reliability indices of the Low Voltage Direct Current(LVDC) distribution system considering arrangement of power electronics, layout of the distribution system, and distance between load points.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.253-259
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• 2016

This study demonstrates the result of mooring analysis for five spread-moored FPSOs having different length-to-breadth (L/B) ratios from 4.5–6.5. FPSOs are subjected to four metocean conditions, ones from the Gulf of Mexico (Hurricane/Loop current condition), West Africa, Nigeria, and Brazil Campos Basin, which are amongst the most typical offshore oil and gas fields. With change in design parameters of OBA (Outer bundle angle) and IBA (Inner bundle angle) combinations, a change in the line tension is demonstrated and the OBA-IBA combinations having the smallest line tension are presented for each L/B ratio and sea, respectively. This study is expected to influence the preliminary design layout of an FPSO spread-mooring system as a function of the L/B ratio and metocean conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.361-366
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• 2012

In this paper, we propose the efficient technique that reduces the number of spot-welds and increases the structural rigidity by using the topology optimization technique. Eigen value analysis is used to evaluate the rigidity of the optimized model. As a first step, the topology optimization is performed to find optimal spot-weld distributions. In this study, the design objective is to maximize the weighted frequencies. The volume fractions of the weld components are used as design constraints, and also the densities of each element in the individual design space are used as design variables. And then, to consider the possibility of spot-weld failure, the contribution rate analysis was performed by using the orthogonal array method of DOE. The spot-welds in the rear panel part are reinforced according to estimation results of the contribution rate analysis. Finally, we obtained optimized spot-weld layout model which has the reduced number of spot-welds and the improved dynamic stiffness.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.18-33
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• 2008

This paper presents design optimization of a new Active Twist Rotor (ATR) blade and conducts its aeroelastic analysis in forward flight condition. In order to improve a twist actuation performance, the present ATR blade utilizes a single crystal piezoelectric fiber composite actuator and the blade cross-sectional layout is designed through an optimization procedure. The single crystal piezoelectric fiber composite actuator has excellent piezoelectric strain performance when compared with the previous piezoelectric fiber composites such as Active Fiber Composites (AFC) and Macro Fiber Composites (MFC). Further design optimization gives a cross-sectional layout that maximizes the static twist actuation while satisfying various blade design requirements. After the design optimization is completed successfully, an aeroelastic analysis of the present ATR blade in forward flight is conducted to confirm the efficiency in reducing the vibratory loads at both fixed- and rotating-systems. Numerical simulation shows that the present ATR blade utilizing single crystal piezoelectric fiber composites may reduce the vibratory loads significantly even with much lower input-voltage when compared with that used in the previous ATR blade. However, for an application of the present single crystal piezoelectric actuator to a full scaled rotor blade, several issues exist. Difficulty of manufacturing in a large size and severe brittleness in its material characteristics will need to be examined.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_1
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• pp.907-915
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• 2020

Specification selection, Layout, specifications and combinations of Power Drives, and Ship motions were studied for FGPP(Floating Gas-fired Power Plants), which are still needed in areas such as the Caribbean, Latin America, and Southeast Asia where electricity is not sufficiently supplied. From this study, the optimal equipment layout in ships was derived. In addition, the difference between engine and turbine was verified through LCOE(Levelized Cost of Energy) comparison according to the type and combination of Power Drives. Analysis of Hs(Significant Height of wave) and Tp(spectrum Peak Period of wave) for places where this FGPP will be tested or applied enables design according to wave characteristics in Brazil and Indonesia. Normalized Sloshing Pressures of FGPP and LNG Carrier are verified using a sloshing analysis program, which is CFD(Computational Fluid Dynamics) software developed by ABS(American Bureau of Shipping). Power Transmission System is studied with Double bus with one Circuit Breaker Topology. A nd the CFD analysis allowed us to calculate linear roll damping coefficients for more accurate full load conditions and ballast conditions. Through RAO(Response Amplitude Operator) analysis, we secured data that could minimize the movement of ships according to the direction of waves and ship placement by identifying the characteristics of large movements in the beam sea conditions. The FGPP has been granted an AIP(Approval in Principle) from a classification society, the ABS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.571-581
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• 2016

This study focused on the characteristics of railway station squares according to layout patterns, which provide transit and links between the station and town. The results were as follows: (1) The analysis examined the characteristics of the railway station to the location and types the proportion: civic center type (59.3%) and ground station (43.7%), and upper railroad station (40.6%). The spatial configurations of the railway station square were obtained: Traffic space and Environment space. (2) The railway station square space configurations was classified as 4 main layout types: Turn place type (PC), Circulation type (PI), Stop place type (PS-1), and Stop place type (PS-2) (3) The average size for each type of railway station square layout patterns of the Location was larger than the civic center type ($16,882.3m^2$) to suburbs type ($37,698.9m^2$). The average form for each type of a railway station square layout patterns of the Location was the civic center type (1.00:0.73) and suburb type (1.00:0.37).

• Journal of the Korean Institute of Educational Facilities
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• v.23 no.1
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• pp.43-54
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• 2016

The purpose of this study was to survey teachers' perception of classroom space utilization through analyzing the physical environment of elementary school classrooms (56 classrooms in 10 schools). Most of the teachers arranged desks in the two person parallel type (sectional layout : standard type) for their classes. Although the number was small, some classrooms used the T type, H type, U type, group type, and the teachers of such cases used these layouts for children's play activities or group learning. Some teachers changed the desk layout depending on the contents of learning or for different atmosphere of class, but about 40% of the teachers used the same classroom layout without any change during a semester. When the teachers' perception of classroom space utilization was examined according to the type and change of desk layout, the quantity and characteristics of posts, the position of posting spaces, and the size of activity spaces in the classroom, most of the teachers tended to be conventional without any characteristic, and only 16% of them were relatively active in utilizing classroom spaces. In addition, teachers of a relatively small class were more active in utilizing classroom spaces. In particular, perception was very low to utilize the classroom as a space for children's life or play activities or various types of learning. These findings suggest that it is necessary to improve teachers' perception of classroom space utilization in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.1
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• pp.55-70
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• 2003

Ammunition magazine, which is installed on the ground, has difficulty in protecting from the external attack, and accidental explosion should cause great damage to the life and property. For these reasons, it is needed to develop underground magazine that it has the advantages of safety, security and maintenance. This paper introduce the design case for blasting facilities, which should resist blasting pressure, as well as layout of underground magazine, which takes a safety for explosion and a working space of loading/unloading machine into consideration. On the layout, in case of ${\bigcirc}{\bigcirc}$ underground magazine, put three storage chambers in position almost parallel with principle stress direction, where less effected on discontinuity and hard rock area. Also, secured safe distance according to safety criteria of the Defense Ministry, and verified suitable layout by trace simulation for loading/unloading machine on working stage. Blasting design was performed on evaluation of maximum blast pressure between donar and acceptor chambers, and design condition for blast door, valve, etc. Diminution facilities against explosion, such as thrust block or debris trap, determined its size after plan in accordance with blasting criteria and calculation by structural analysis.

• Journal of the Korean Institute of Gas
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• v.16 no.2
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• pp.52-59
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• 2012

The sprinkler system is regarded as the most effective fire extinguishing system. In this study, we proposed a sprinkler layout optimization framework based on fire simulation and mathematical programming. As a case study, the target space in the form of ordinary residence was set up with the size of $5.2m(L){\times}5.4m(W){\times}2.4m(H)$, and we constructed the fire scenario that polyurethane couch was ignited through carelessness. And we simulated and analyzed fire speed, temperature change and heat release rate according to the type and number of sprinklers installed. Through the formulation of installation and damage costs depending on sprinklers, the sprinkler layout showing optimal performance was resulted from mathematical programming.