• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.16-24
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• 2007

The high-frequency analysis method of back-scattering cross section spectrum of rotating targets is established. The time history of the back-scattering cross section is calculated using a quasi-stationary approach, based on a physical optics and a physical theory of diffraction, combining an adaptive triangular beam method to consider the shadow effect. And the spectra of back-scattering cross section by the Doppler effect are analyzed applying a simple fast Fourier transform method to its time history. The numerical calculation for rotating targets, such as rotating metal plates and underwater propeller, are carried out. The time history appears to be periodic with respect to the number of wings. The backscattering cross section spectrum level and its frequency shift are dependent on the rotating speed, direction, and the shape of the targets.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.111-122
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• 2018

The purpose of this study was to investigate the bodice prototype method suitable for the upper body shape of old-old aged women using the 3D anthropometric data. And it was to provide the basic data for the upper body garments of old-old aged women. In the overall appearance evaluation, the B pattern was rated as 4.00, and it was evaluated as the most suitable for the bodice prototype of the old-old aged woman. The E pattern was rated lower than normal, and the L pattern and the S pattern were found to be inadequate for older female bodice prototypes. As a result of the measurement of the waist and bust air gap of bodice prototype, the air gap of the bust was not significantly different between the patterns. But the waist air gap showed the largest difference between the L pattern and the S pattern. As a result of evaluating the appearance, the amount of space in the state of 3D simulation, and the air gap, the pattern B appeared to be the most appropriate prototype for the old-old aged women's body shape. However, there is a tendency that the shoulder end point is biased toward the back, so it is necessary to set the inclination of the back shoulder line to be more gentle. Conversely, the front shoulder should be more inclined. In the case of the 3D simulation, the B pattern showed that the other parts generally fit well. In the case of the 3D simulation program used in this study, it was evaluated that it is suitable only for the normal body shape because it is impossible to set the isometric angle which is one of the characteristics of the older female body shape. A study on the bodice prototype suitable for the bent body shape should be carried out through experiments on the actual body shape of various elderly women. In order to cope with the increase of elderly people who are familiar with digital, I think it is necessary to develop an avatar that reflects the old female body shape.

• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.1
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• pp.143-154
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• 2021

This study attempted to develop winter jackets and pants patterns reflecting the latest comfortable and active school uniform trends, using middle school boy avatars having various body shapes. Jacket and pants pattern-drawing methods and margins differed. Based on the results, research prototypes were prepared. Then, virtual wear prospective drawings, clothing pressure, and appearance were assessed according to body shape. Jackets were assessed using 25 factors, while pants were assessed using 19. Then, correlations between the jackets and pants were analyzed. According to the analysis, the reason why the dart & tuck position and margin were rated low was confirmed. In a virtual wear assessment on jacket patterns by body shape, a significant difference was found in all categories, except for fit and shape at the front bottom, sleeve length on the side, and the center back line. The virtual wear assessment on the pants patterns by body shape also revealed a significant difference in all categories, except for pants length. In jackets, a significant influence was observed around the shoulders and waist in Type 1 and around the belly in Type 2. On the contrary, for pants, a significant influence was found around the hip and waist in Type 1 and around back crotch in Type 2. Therefore, they should be considered when making of jackets and pants. The above results suggested that jacket and pants patterns should vary depending on body shape. It is anticipated that there should be further studies comparing brand-name school uniforms for middle school girls and school uniforms by body shape.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.79-86
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• 2007

The shape of excessive penetration mainly depends on welding conditions(welding current and welding voltage), and welding process(groove gap and welding speed). These conditions are the major affecting factors to width and height of back bead. In this paper, back-bead prediction and weldability estimation using artificial neural network were investigated. Results are as follows. 1) If groove gap, welding current, welding voltage and welding speed will be previously determined as a welding condition, width and height of back bead can be predicted by artificial neural network system without experimental measurement. 2) From the result applied to three weld quality levels(ISO 5817), both experimented measurement using vision sensor and predicted mean values by artificial neural network showed good agreement. 3) The width and height of back bead are proportional to groove gap, welding current and welding voltage, but welding speed. is not.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.896-905
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• 2012

Recently, the application of the plastic material to automotive components and structures has steadily increased to satisfy demands on the saving of overall weight and the improvement of energy efficiency. The objective of this paper is to investigate the development of a bumper back-beam using a thermoplastic olefin (TPO). The bumper back-beam was designed to be manufactured from the injection molding process. In order to obtain a proper design of the bumper back-beam, three-dimensional finite element analyses were performed for various design alternatives. Stress-strain curves for different strain rates were measured by high speed tensile tests of the TPO to consider strain rate effects in the FEA. The influence of the sectional shape and the rib formation on the contact force-intrusion curves, the deflection and the energy absorption rate of the bumper back-beam was examined. From the results of the examination, a proper design of the bumper back-beam was acquired. The bumper back-beam consisting of TPO was fabricated from the injection moulding process and the vibration welding. Pendulum crash tests were carried out using the fabricated bumper back-beam. The results of the tests showed that the designed bumper back-beam can satisfy requirements of the federal motor vehicle safety standard (FMVSS). Through the comparison of the previously designed bumper back-beam with the newly designed bumper back beam, it was noted that the weight of the designed bumper back-beam is lighter than that of the previously designed bumper back beam by nearly 16 %. In addition, it was considered that the newly designed bumper back beam can improve recycling of the bumper back-beam.

• Journal of the Korea Furniture Society
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• v.17 no.2
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• pp.57-68
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• 2006

This study understands rockers of today and supplies basic data of design and manufacture studying pattern change of rockers arisen in West, there is the purpose. Also, this study is investigated by dividing theoretical background of rockers, 7 kinds of American traditional rockers and European rockers from 18th century to opening part of 20th century and contemporary rockers since 20th century. The theoretical background and the style of 2 rockers (Windsor rocker, Boston rocker) were investigated to study the stylistic changes of rockers. Originally a rocker was invented by a European farmer around 1700. It developed to a household which equip practicality and comfortablness in the United States than Europe. Early rockers in a primal form appeared in the 1740s in the United States. American early rockers connected skate to established chair bridge. Rockers are deep connection with family's emotion. Rockers can provide playing functions for children and medically treating functions for adults. Windsor Rockers developed by attaching skate is mammy bench and according to shape of back form bow or hoop-back rocker, birdcage rocker, comb-back rocker. Windsor Rockers formed peculiar American tradition of craftsman furniture through structure that have a unique back of a chair and round seat. Boston Rockers were the first chairs made by mass production method. They show a particular shape with S-curve style seat and rectangular crest at the upper part of the back. Often Crests were decorated by stenciled pattern with curled leaves such as rosettes and scrolled designs.

• Fashion & Textile Research Journal
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• v.10 no.5
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• pp.660-667
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• 2008

The purpose of this study was to modify a Flared Skirt for women according to the somatotype of lower body. The subjects for the wear test were 3 students, who were in $mean{\pm}1{\sigma}$ each somatotype. The results of this study are as follows: First, the Flared Skirt pattern was modified according to each type. The front waist line rising measurement proposed for type 1 and type 2 were 0.5cm, because of lower front silhouette with waist shape. The back waist line rising measurement proposed for type 2 was 1cm and type 3 was 0.5cm, because of lower back shape with hip. Second, the wave-height of nodes were regular at front and back in type 1. Also, the wave-height of nodes were evenly distributed side and center. The variation ratio of wave-height of back nodes were lower than existing pattern in type 2 and type 3. It means the variation ratio of wave-height of back nodes were regular in modification pattern. Altogether, modification patterns were more regular and lower than existing pattern in the number of nodes, the distribution ratio of nodes, the wave-height of node, the variation ratio of wave height of nodes.

• Journal of the Korean Geotechnical Society
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• v.25 no.11
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• pp.61-73
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• 2009

In this study, we grasped the resistance state of the back ground which had a notable influence on computing the lateral resistance of the laterally loaded single pile in the homogeneous ground by the model test. In order to grasp a resistance behavior, we have to know the deformation area of the back ground and the side failure angle other than the rotation point of pile and vertical failure angle of back ground which were proposed by Bae & Kim in 2008. We found out in this test the characteristics of the behavior of the back ground in accordance with the shape and size of the pile and ground density. We examined the interrelationship of the relative density of sand, the size and the sectional shape of the pile as well.

• Transactions of Materials Processing
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• v.21 no.7
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• pp.397-402
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• 2012

The flange hub is a main component in an automotive steering system. In general, the flange hub are fabricated by mechanical machining, which is a process where material waste is inevitable. It is well-known that a net-shape cold forging cannot only reduce material waste but can also improve the mechanical strength of the final product. Thus, a forging process design was conducted for production of a flange hub. Significant spring-back occurs around the flange due to its small thickness in conjunction with the residual stresses after forging. In order to achieve the required dimensional accuracy, a process design with appropriate spring-back control is needed. In this study, a modification of the forging die was designed based on FE analysis with the purpose of spring-back compensation. Four kinds of different die designs were evaluated and the optimum design has two times less spring-back than the initial design. The compensation angle of the optimum design is 0.5 degrees. The results have been experimentally confirmed by cold forging of a flange hub and comparing the amount of spring-back between the actual component and the FE analysis.

• Journal of Auto-vehicle Safety Association
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• v.11 no.4
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• pp.57-62
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• 2019

The seat back frame of the vehicle is subjected to load on the passenger behavior. Because of steel material, it is necessary to optimize the frame considering lightweight and safety. In this paper, finite element analysis is used for the optimal design of the seat back frame. First, a lightweight material is applied to reduce the weight of the seat back frame. Secondly, the design position of the pipe part fastened in the seat back frame was selected by considering the strength against the load generated by the occupant. Third, the shape of the side frame was derived by performing the phase optimization analysis for the AFT load condition. And we have compared the initial model with the optimal model to verify the light weighting and safety. As a result, the optimal design model of the seat back frame satisfying the weight reduction and safety has been proposed.