• Korea Real Estate Review
• /
• v.27 no.3
• /
• pp.71-86
• /
• 2017

The purpose of this study was to apply the deep running method to real estate price index predicting and to compare it with the time series analysis method to test the possibility of its application to real estate market forecasting. Various real estate price indices were predicted using the DNN (deep neural networks) and LSTM (long short term memory networks) models, both of which draw on the deep learning method, and the ARIMA (autoregressive integrated moving average) model, which is based on the time seies analysis method. The results of the study showed the following. First, the predictive power of the deep learning method is superior to that of the time series analysis method. Second, among the deep learning models, the predictability of the DNN model is slightly superior to that of the LSTM model. Third, the deep learning method and the ARIMA model are the least reliable tools for predicting the housing sales prices index among the real estate price indices. Drawing on the deep learning method, it is hoped that this study will help enhance the accuracy in predicting the real estate market dynamics.

• Journal of the Korean Geotechnical Society
• /
• v.31 no.10
• /
• pp.61-76
• /
• 2015

Recently, geotechnical engineering researches have been conducted on the Limit State Design (LSD) for deep and shallow foundations; however, there are very few studies on the retaining wall. As a basic study for the introduction of the LSD of a railway retaining wall, this study evaluates whether the reliability index satisfies the target reliability index for each failure mode in the standard drawing of the retaining wall. It also analyzes the feasibility of the LSD method by using the Load and Resistance Factor Design (LRFD) for the standard drawing of a retaining wall. In a portion of the standard drawing of the railway retaining wall, the reliability indices of the sliding and bearing capacity failure modes did not satisfy the target reliability index, and could not satisfy the limit state by the LRFD. Hence, the standard drawing of the railway retaining wall will need to be revised if the LSD is to be applied.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.30 no.1
• /
• pp.1-13
• /
• 2024

Background: The purpose of this study was to investigate the effects of stabilization exercise performed after abdominal drawing exercise using pressure biofeedback for 8 weeks on pain level, performance of transverse abdominis, back pain disability index, and quality of life in women in their 30s less than one year after giving birth. Methods: A total of 20 women who voluntarily participated less than one year after giving birth were randomly divided into a control group and an experimental group. The control group was subjected to abdominal drawing exercise before lumbar stabilization exercise, and the experimental group was subjected to abdominal drawing exercise using pressure biofeedback before lumbar stabilization exercise thrice a week for eight weeks. The quadruple visual analog scale (QVAS), the performance of transverse abdominis, the Korean version of the Oswestry disability index (KDOI), the inventory of functional status after childbirth (IFSAC), and the Short Form-12 item (SF-12) were evaluated before and after the intervention. Results: Except for the Physical Components Summary Scale of SF-12, after the intervention, the experimental group showed significant improvement in QVAS, performance of Transverse abdominis , KDOI, and Mental Components Summary Scale of SF-12 compared to the control group. Conclusion: Selective deep muscle activation through abdominal drawing exercises using pressure biofeedback can help rehabilitation for women after postpartum.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.7
• /
• pp.2246-2256
• /
• 1996

To investigate the effect of material and precess variables on stamping formability of sheet materials, simulations for the cup drawing and the Yoshida buckling test were carried out using ABAQUS, commercial nonlinear finite element analysis code. The various factor effects on stamping formability of sheet materials were analyzed by the designed process according to Taguch's orthogonal array experiment. Cup drawing simulation showed that local neckling was very sensitive to plastic anisotropy parameter of sheet material and friction coefficient between sheet and tool interface. Simulations for the Yoshida buckling test have clarified that buckling behaviour of sheet material was mostly susceptible to yield stress and sheet thickness mostly. However, plastic anisotropy parameter and strain hardening coefficient affect moderately buckling behaviour of steel sheets after the buckling initiation.

• Transactions of Materials Processing
• /
• v.8 no.1
• /
• pp.14-21
• /
• 1999

Trapezoid cups and square ones have been deep-drawn to 45mm in depth. Displacements and strains have been analysed by FEM and experiment. Strains and effective strains in the corner flanges of trapezoid cups have been compared with those in square cups. The results have shown that because of shear strains on the corner flange, it is necessary to adopt effective strain for comparing strains, mean vale of effective strains in the corner flange with a corner angle of 72 degrees is narly equal to those with a corner angle of a right angle and mean value of effective strains with a corner angle of 102 degrees is smaller than those with a corner angle of a right angle.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1998.03a
• /
• pp.151-154
• /
• 1998

Stainless steel sheets are widely used to produce electrical appliances. But there are various problems occured in forming stainless steel sheets such as scratch, local fracture, earing. So the productivity of electrical appliances made of stainless steel sheets is decreased. And it is very important to improve the formability of stainless steel sheets. In this study, rectangular cup drawing tests have been carried out to obtain optimum process parameters for improving the formablity of stainless steel sheets. In the tests, selected process parameters are materials of dies and punches, lubricating conditions, and blank holding force. From the test results, we suggest the appropriate conditions to be applicable to the actual manufacturing processes.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.7
• /
• pp.865-873
• /
• 2013

The deep drawing and ironing (DDI) process involving the use of a high-capacity horizontal press is used for manufacturing acompressed natural gas (CNG) pressure vessel. However, some variables of the DDI process have been determined based on the experiences of workers, and the short die life needs to be improved for manufacturing the pressure vessel withhighquality and lowcost. In this study, process variables such as the draw ratio, distance between dies, radius of rounding of drawing die, and angle of ironing die are chosen to enhance the reliability and improve the die life based on previous studies and experiences. The draw ratio limits at which no tearing or wrinkling occurs are determined using FEA, and the distances between dies, radius of rounding of drawing die, and angle of ironing die are optimized by the DOE method. The results of the optimal process variables are compared with those of the existing DDI process for verifying their effectiveness.

• Design & Manufacturing
• /
• v.14 no.1
• /
• pp.22-29
• /
• 2020

The analysis was carried out using the press molding analysis program by applying six parameters such as material type change, material thickness, friction coefficient, r_p, r_d and blank holder pressure. As a result of CAE analysis of the soft material DC04 and the relatively hard material HX300LAD, the thickness of the punch R part of the soft material was significantly reduced. The flange portion is greatly increased in thickness in the hard material by the compression action. As a result of considering the deformation amount of 0.6mm, 1.0mm, 1.5mm according to the material thickness, the influence of the thickness is considered to be very small. In case of the material thickness of 0.6mm, the rate of change increases due to the deep drawing depth relative to the material thickness. The sizes of the punches R and die R have the greatest influence on the change in thickness of the material in drawing molding, the smaller the punch R, the thinner the edges of the product, The larger the R of the die, the greater the material thickness of the flange portion. As the coefficient of friction and the blank holder pressure increase, the frictional force of the flange portion increases, which increases the radial force in the drawing process and increases the thickness change of the flange portion.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.05a
• /
• pp.281-281
• /
• 2007

• Journal of the korean Society of Automotive Engineers
• /
• v.14 no.6
• /
• pp.9-22
• /
• 1992

본 글에서는 판재의 스탬핑 성형성 평가를 위해 소재 제조업체와 자동차업체에서 널리 사용되고 있는 2,3개의 대표적인 모사실험과 평면변형장출실험을 소개하고 각각의 특징들에 대하여 논하고자 한다. 1. 딥 드로잉실험(deep drawing test after swift). 2. 돔 장출실험(dome punch stretching test). 3. 평면변형인장실험(plane strain tension test). 4. 평면변형장출실험(plane strain punch stretching test)