• Journal of the Society of Naval Architects of Korea
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• v.59 no.1
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• pp.39-45
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• 2022

Normal strategy of structure optimization procedure has been minimum cost or weight design. Minimum weight design satisfying an allowable stress has been used for the ship and offshore structure, but minimum cost design could be used for the case of high human cost. Natural frequency analysis and forced vibration one have been used for the strength estimation of marine structures. For the case of high precision experiment facilities in marine field, the structure has normally enough margin in allowable stress aspect and sometimes needs high natural frequency of structure to obtain very high precise experiment results. It is not easy to obtain a structure design with high natural frequency, since the natural frequency depend on the stiffness to mass ratio of the structure and increase of structural stiffness ordinary accompanies the increase of mass. It is further difficult at the grillage structure design using the profiles, because the properties of profiles are not continuous but discrete, and resource of profiles are limited at the design of grillage structure. In this paper, the grillage structure design system under the constraint of high natural frequency is introduced. The design system adopted genetic algorithm to realize optimization procedure and can be used at the design of the experimental facilities of marine field such as a towing carriage, PMM, test frame, measuring frame and rotating arm.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.477-486
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• 2009

This paper deals with the strongest static arches with the solid regular polygon cross-section. Both span length and volume of arch are always held constant regardless the shape functions of cross-sectional depth of regular polygon. The normal stresses acting on such arches are calculated when both static vertical and horizontal point loads are subjected. By using the calculating results of stresses, the optimal shapes of strongest static arches are obtained, under which the maximum normal stress become to be minimum. For determining the redundant of such indeterminate arches, the least work theorem is adopted. As the numerical results, the configurations, i.e. section ratios, of the strongest static arches are reported in tables and figures. The results of this study can be utilized in the field of the minimum weight design of the arch structures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.103-108
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• 2020

Generally, the cargo tank of LPG carriers corresponds to an independent tank Type A defined by the International Maritime Organization (IMO). The outside of the tank is insulated by polyurethane foam, and the tank is made of expensive low temperature steel that can withstand temperatures as low as -50℃. The cargo tank is composed of outer shell plates, bulkheads, stiffeners, web frames, and stringers. Among them, the outer shell plates, bulkheads, and stiffeners can be designed without structural analysis by the Classification Rules and are constructed easily through optimal design. On the other hand, optimal design, including numerous structural analysis, is not performed because web frames and stringers should be designed and approved through structural analysis. Only adequate design, which determines the design dimensions through several dozen structural analysis, is performed. In this study, for finite element analysis, eight loading conditions were applied, and the deformation of the entire ship for each loading condition was considered. The minimum weight design was performed for the web frames of cargo tanks in the 82,000 ㎥ LNG carrier through the gradient-based optimization technique, and the weight was reduced by approximately 108 tons per ship.

• Journal of the Korean Geotechnical Society
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• v.32 no.2
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• pp.53-62
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• 2016

Among several factors controlling soil compaction, temperature is the factor that varies with region and season. Although earthwork is performed in many projects in the cold regions of the earth, studies on quantifying soil compaction associated with temperature are limited. This experimental study investigates the temperature effect on the soil compaction of cohesionless soil. Jumunjin sand was selected for the tests to represent cohesionless clean sand, which is widely used as an engineering fill at petrochemical projects such as northern Alberta of Canada and Russia. The laboratory test program consists of performing a series of standard proctor tests varying temperature of soil samples ranging from $-10^{\circ}C$ to $17^{\circ}C$. Test results indicate that soil specimen volume expansion occurred from bulking and its range was 0% to 6% with zero above temperature. For increasing temperature from $0^{\circ}C$ to $17^{\circ}C$, water content corresponding to maximum volume (minimum dry unit weight) was decreased and water content corresponding to minimum volume (maximum dry unit weight observed after reaching minimum dry unit weight) was slightly increased with increasing temperature. In zero below temperature, dry unit weight gradually decreased with increasing water content. In this case, no bulking effect was found and soil specimen volume increased due to the higher unit volume of ice.

• Korean Journal of Plant Resources
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• v.22 no.1
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• pp.1-4
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• 2009

This study was carried out to evaluate ecological growth characteristics of forty castor bean collections for biodiesel utilization. The emergence date and it's rate of collections was 15-16 days and 82.5%, respectively. It took 63-68 days from emergence to flowering. Stem length was ranged from 173 to 251 cm with an average 211.8 cm. The average stem diameter was 24.2 cm, and showed the high occurrence as 52.5% at the 20.4-24.9 cm. The node number was widely distributed as 13-22 and the average node number was 18.9. The seed numbers were widely distributed as 7-33ea, and the average liter weight of seed was 502.9 g of which minimum weight was 432.3 g and maximum weight was 572.5 g, and the gap between maximum and minimum was 140.2 g. It showed high difference. The 100 grain weight was distributed as 20.3 g-38.3 g which showed high differences between small grain and large grain collections. The seed numbers per plant were varied as 72 at the minimum and 1,011 at the maximum number, and average seed number was 465.2. The total yields of seed per plant were varied as 20 g-266.2 g, and the average yields were 128.1 g.

• Journal of Biosystems Engineering
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• v.36 no.1
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• pp.48-57
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• 2011

The computer vision system was designed and constructed to measure the weight of a dairy cattle. Its development involved the functions of image capture, image preprocessing, image algorithm, and control integrated into one program. The experiments were conducted with the model dairy cattle and the real dairy cattle by two ways. First experiment with the model dairy cattle was conducted by using the indoor vision experimental system, which was built to measure the model dairy cattle in the laboratory. Second experiment with real dairy cattle was conducted by using the outdoor vision experimental system, which was built for measuring 229 heads of cows in the cattle facilities. This vision system proved to a reliable system by conducting their performance test with 15 heads of real cow in the cattle facilities. Indirect weight measuring with four methods were conducted by using the image processing system, which was the same system for measuring of body parameters. Error value of transform equation using chest girth was 30%. This error was seen as the cause of accumulated error by manually measurement. So it was not appropriate to estimate cow weight by using the transform equation, which was calculated from pixel values of the chest girth. Measurement of cow weight by multiple regression equation from top and side view images has relatively less error value, 5%. When cow weight was measured indirectly by image surface area from the pixel of top and side view images, maximum error value was 11.7%. When measured cow weight by image volume, maximum error weight was 57 kg. Generally, weight error was within 30 kg but maximum error 10.7%. Volume transform method, out of 4 measuring weight methods, was minimum error weight 21.8 kg.

• The Research Journal of the Costume Culture
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• v.11 no.3
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• pp.441-446
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• 2003

Water-insoluble chitosan with molecular weight of 2,000,000, 500,000, 80,000, and 40,000 and more than 90% of degree of deacetylation were used to test antibacterial activity of chitosan against a pathogenic bacteria, methicillin resistant Staphylococcus aureus(MRSA), which is being issued in the world. As experimental method, Agar plate Smear Method and Agar plate Contact Method were used. The moleculur weight of chitosan didn't exert significant influences on its antibacterial activity against MRSA but chitosan having molecular weight 40,000, 80,000 and 150,000 showed the excellent antibacterial activity. The antibacterial efHciency was excellent in applying it after chitosan was dissolved in acetic acid solution, while the antibacterial efficiency was not expressed nearly in case of applying after chitosan was dissolved in neutral water. Therefore, it is considered that chitosan can show the antibacterial efficiency only if a positive ion status of -NH₃/sup +/ is maintained. MIC of chitosan/acetic acid solution and cotton fabrics finished with chitosan/acetic acid solution showed in concentration of 0.05%.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.177-184
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• 2020

In this paper, we studied to direction of arrival (DoA) estimation to use DoA and optimum weight algorithms in coherent interference channels. The DoA algorithm have been considerable attention in signal processing with coherent signals and a limited number of snapshots in a noise and an interference environment. This paper is a proposed method for the desired signal estimation using MUSIC algorithm and adaptive beamforming to compare classical subspace techniques. Also, the proposed method is combined the updated weight value with LCMV beamforming algorithm in adaptive antenna array system for direction of arrival estimation of desired signal. The proposed algorithm can be used with combination to MUSIC algorithm, linearly constrained minimum variance beamforming (LCMV) and the weight value method to accurately desired signal estimation. Through simulation, we compare the proposed method with classical direction of in order to desired signals estimation. We show that the propose method has achieved good resolution performance better that classical direction arrival estimation algorithm. The simulation results show the effectiveness of the proposed method.

• Geomechanics and Engineering
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• v.20 no.6
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• pp.527-536
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• 2020

The paper represents an optimization algorithm for reinforced concrete retaining wall design. The proposed method, called Rao-3 optimization algorithm, is a recently developed algorithm. The total weight of the steel and concrete, which are used for constructing the retaining wall, were chosen as the objective function. Building Code Requirements for Structural Concrete (ACI 318-05) and Rankine's theory for lateral earth pressure were considered for structural and geotechnical design, respectively. Number of the design variables are 12. Eight of those express the geometrical dimensions of the wall and four of those express the steel reinforcement of the wall. The safety against overturning, sliding and bearing capacity failure were regarded as the geotechnical constraints. The safety against bending and shear failure, minimum and maximum areas of reinforcement, development lengths of steel reinforcement were regarded as structural constraints. The performance of proposed algorithm was evaluated with two design examples.

• Composites Research
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• v.28 no.5
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• pp.297-310
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• 2015

This study aims to develop efficient composite laminates for buckling load enhancement, interlaminar shear stress minimization, and weight reduction. This goal is achieved through cover-skin lay-ups around skins and stiffeners, which amplify bending stiffness and defer delamination by means of effective stress distribution. The design problem is formulated as multi-objective optimization that maximizes buckling load capability while minimizing both maximum out-of-plane shear stress and panel weight. For efficient optimization, response surface methodology is employed for buckling load, two out-of-plane shear stresses, and panel weight with respect to one ply thickness, six fiber orientations of a skin, and four stiffener heights. Numerical results show that skin-covered composite stiffened panels can be devised for maximum buckling load and minimum interlaminar shear stresses under compressive load. In addition, the effects of different material properties are investigated and compared. The obtained results reveal that the composite stiffened panel with Kevlar material is the most effective design.