• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.415-420
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• 2005

LMTT (Linear Motor-based Transfer Technology) is the horizontal transfer system for yard automation, which has been proposed to take the place of AGV (Automated Guided Vehicle) in the maritime container terminal. The system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle car. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research, structural optimization for a mover of shuttle car is performed to minimize the weight satisfying design criteria. The objective function is set up as weight. On the contrary, the design variables are transverse, longitudinal and wheel beams' thicknesses and its height, and the constraints are considered as strength and stiffness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.100-109
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• 2011

Recently, the concrete-steel hybrid extradosed bridge has been proposed as alternative bridge type at long span site. The hybrid extradosed bridge adopts light orthogonal deck girder instead of heavy concrete deck girder at the center span of bridge, and it enables to construct long-span bridge. And also, for this bridge type the decrease of self-weight of girder enables to reduce girder depth and side span length of extradosed bridge, so its type has more efficient structural behavior and makes it possible to perform optimal bridge design. Therefore, it is very important to set up the procedure and parameters of optimal design for concrete-steel hybrid extradosed bridge. In this study, the effects of design parameters (the variation of pylon height, bridge deck depth and orthogonal deck girder length) are discussed. And numerical analysis and sensitivity analysis are carried out according to these parameters. And design weight values about these parameters are quantitatively suggested to reflect characteristics of concrete-steel hybrid bridge.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4171-4177
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• 2013

Outer tie rod is lighter than other, but there is the trend item weight and the number is increasing due to vehicle performance improvement. Thus, to improve vehicle fuel efficiency, weight lightening is essential. Therefore, this research performed the finite element analysis to investigate the structural performance of the outer tie rod for an electrical vehicle. This study was performed as the preliminary study for a lightweight design of the outer tie rod. The weight of outer tie rod was optimized by adopting the steel material and applying the trial and error method. The strengths due to durability and buckling should be considered in the structural design of an outer tie rod. Furthermore, the meta model-based optimization was applied to obtain its lightweight design, leading to 9 % weigh reduction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.22-29
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• 2015

Modern structures is the tendency of being increasingly taller and larger. The concrete with large weight has the disadvantage of increasing the weight on the structure. therefore, the method of carrying out the weight saving of the concrete is required. one of such method is to use a lightweight aggregate. However, studies on structural lightweight concrete, lacking for the recognition of the lightweight concrete, so also is lacking. therefore it is necessary to study on the physical characteristic value of the lightweight concrete. In this study, in order to investigate the tensile properties of lightweight concrete, Crack mouth opening displacement (CMOD) experiments were carried out. the fracture energy of the lightweight concrete subjected to inverse analysis were derived from the CMOD experimental results.

• Journal of Navigation and Port Research
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• v.26 no.3
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• pp.317-322
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• 2002

In this study, structural optimum design was applied to the girder of magnet over head crane. The optimization was carried out using ANSYS Code for the deadweight of girder, especially focused on the thickness of its upper, lower, side and reinforced plates. The weight could be reduced up to around 15% with constraints of its deformation, stress, natural frequency and buckling strength. The structural safety was also verified by the buckling analysis of its panel structure. It might be thought to be very useful to design the conventional structures for the weight save through the structural optimization. Also this paper grasped the sensitivity influenced the design variables upon the objective function and the state variables.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.2
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• pp.180-187
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• 2018

Corrugated bulkhead has been adopted for cargo tank bulkheads of commercial vessels such as bulk carriers, product oil carriers and chemical tankers. It is considered that corrugated bulkhead is a preferred structural solution, compared to the flat stiffened bulkhead, due to several advantages such as lower mass, easier maintenance and smaller corrosion problems. Many researches to find the optimum shape of corrugated bulkhead have been mostly carried out for bulk carriers. Compared to corrugated bulkheads of bulk carriers, ones of chemical tankers are more complicated since they are composed of transverse and longitudinal bulkheads, and they are made of higher priced materials. The purpose of this study is the development of minimum weight design method for corrugated bulkhead of chemical tankers. Evolution strategy is applied as an optimization technique. It has been verified from many researches that evolution strategy searches global optimum point prominently by using multi-individual searching technique. Multi-individual searching methods need excessive time if they connect to 3-D finite element model for repetitive structural analyses. In order to resolve this issue, 2-D beam element connected to deck and lower stool is substituted for a corrugated structure in this study. To verify the reliability of the structural responses by idealized 2-D beam model, they have been compared with ones by 3-D finite element model. In this study, optimum design for corrugated bulkhead of 30 K chemical tanker has been carried out, and the results by developed optimum design program have been compared with design data of existing ship. It is found out that optimum design is about 9% lighter than one of existing ship.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.1-7
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• 2017

The development of effective design allowable values for unmanned composite aircraft is an issue of paramount concern for the industry. The application of conventional manned aircraft structural certification methods to unmanned aircraft such as prototype and technology demonstrators, can lead to excessively long development time and costs. In this paper, the determining method of composite structure design allowable values for light composite unmanned aircraft is presented to reduce to the structural weight. This paper seeks to show the applicability of composite B-basis material values as a design allowable of light composite unmanned aircraft structures. A review of different civil and UAV targets failure probability is given. From the results, the researchers can know that the requirements of light composite unmanned aircraft design allowable should be alleviated, compared to manned composite aircrafts.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.123-128
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• 2019

The structural analysis for light weight on the brake pedal of the racing spec installed with the balance bars of the four models were performed in this study. By utilizing two materials of steels and aluminum alloys, four shapes were analyzed. It is generally assumed that the magnitude of force a person may incur when riding in a car is 1000 N. The fixed points are designated as the parts at which the bolts and pedals are fixed and the mounting part of the balance bar applied by the stress transmitted through the rod when the pressure of the master cylinder rises and the operation stops. Through this analysis study, it is thought that the vulnerability of each brake pedal model can be investigated and the transmission efficiency of the brake pedal can be increased by light weight. As the design data with the durability of brake pedal obtained on the basis of this study result are utilized, the esthetic sense can be shown by being grafted onto the part of car at real life.

• Molecules and Cells
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• v.43 no.12
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• pp.1035-1045
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• 2020

The Drosophila genome contains four low molecular weight-protein tyrosine phosphatase (LMW-PTP) members: Primo-1, Primo-2, CG14297, and CG31469. The lack of intensive biochemical analysis has limited our understanding of these proteins. Primo-1 and CG31469 were previously classified as pseudophosphatases, but CG31469 was also suggested to be a putative protein arginine phosphatase. Herein, we present the crystal structures of CG31469 and Primo-1, which are the first Drosophila LMW-PTP structures. Structural analysis showed that the two proteins adopt the typical LMW-PTP fold and have a canonically arranged P-loop. Intriguingly, while Primo-1 is presumed to be a canonical LMW-PTP, CG31469 is unique as it contains a threonine residue at the fifth position of the P-loop motif instead of highly conserved isoleucine and a characteristically narrow active site pocket, which should facilitate the accommodation of phosphoarginine. Subsequent biochemical analysis revealed that Primo-1 and CG31469 are enzymatically active on phosphotyrosine and phosphoarginine, respectively, refuting their classification as pseudophosphatases. Collectively, we provide structural and biochemical data on two Drosophila proteins: Primo-1, the canonical LMW-PTP protein, and CG31469, the first investigated eukaryotic protein arginine phosphatase. We named CG31469 as DARP, which stands for Drosophila ARginine Phosphatase.

• Advances in materials Research
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• v.11 no.2
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• pp.147-164
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• 2022

This study aims to investigate the influence of scoria aggregate (SA) and silica fume (SF) as a replacement of conventional aggregate and ordinary Portland cement (OPC), respectively. Three types of concrete were prepared namely normal weight concrete (NWC) using limestone aggregate (LSA) and OPC (control specimen), lightweight concrete (LWC) using SA and OPC, and LWC using SA and partial SF (SLWC). The representative workability and compressive strength properties of the developed concrete were evaluated, and the results were correlated with non-destructive ultrasonic pulse velocity and Schmidt hammer tests. The LWC and SLWC yielded compressive strength of around 30 MPa and 33 MPa (i.e., 78-86% of control specimens), respectively. The findings indicate that scoria can be beneficially utilized in the development of structural lightweight concrete. Present renewable sources of aggregate will preserve the natural resources for next generation. The newly produced eco-friendly construction material is intended to break price barriers in all markets and draw attraction of incorporating scoria based light weight construction in Saudi Arabia and GCC countries. Findings of the SWOT analysis indicate that high logistics costs for distributing the aggregates across different regions in Saudi Arabia and clients' resistant to change are among the major obstacles to the commercialized production and utilization of lightweight concrete as green construction material. The findings further revealed that huge scoria deposits in Saudi Arabia, and the potential decrease in density self-weight of structural elements are the major drivers and enablers for promoting the adoption of lightweight concrete as alternative green construction material in the construction sector.