• Journal of the Korean Society of Costume
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• v.58 no.8
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• pp.120-136
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• 2008

This study examined sewing methods used to reinforce the opening of clothes of the Joseon period. Through the analysis of a total of 117 clothing items of the Joseon period, the following results were obtained. 1. Most costumes of the Joseon period had the opening. The purpose of the opening was to allow one to put on and take off a costume, act comfortably, and turn a costume Inside out. The opening was located on the Side, Conte. Back, fgwi(Side opening of pants), Wristband, Armhole, and Godae(the bark part of the collar). 2. As the opening tended to get easily worn out, it was often reinforced. The 1911owing three methods were used to reinforce the opening of clothing items of the Joseon period: a method to attach a cloth such as Dang, Binding, and Badae; a method using a variety of knots; and a method by sewing stitches such as a sort of cross stitch called Satteugi, Prick stitch, and Loop. 3. The most frequently used reinforcing method was the one that used a knot(34 items), followed by the one by sewing Satteugi(27 items), and the one using Dang(25items). The most frequently detected location of the opening was Side(59 items), followed by Agui(37 items), Wristband(19 items), and Center Back(13 items). 4. The reinforced opening made a costume more endurable and elastic, decorative and neat.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.64-70
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• 2003

This paper suggests a systematic methodology to predict chip forms using the experimental design technique and the neural network. Significant factors determined with ANOVA analysis are used as input variables of the neural network back-propagation algorithm. It has been shown that cutting conditions and cutting tool shapes have distinct effects on the chip forms, so chip breaking. Cutting tools are represented using the Z-map method, which differs from existing methods using some chip breaker parameters. After training the neural network with selected input variables, chip forms are predicted and compared with original chip forms obtained from experiments under same input conditions, showing that chip forms are same at all conditions. To verify the suggested model, one tool not used in training the model is chosen and input to the model. Under various cutting conditions, predicted chip forms agree well with those obtained from cutting experiments. The suggested method could reduce the cost and time significantly in designing cutting tools as well as replacing the“trial-and-error”design method.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.171-180
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• 2016

Basel committee suggests using Value-at-Risk (VaR) and expected shortfall (ES) as a measurement for market risk. Various estimation methods of VaR and ES have been studied in the literature. This paper compares semi-parametric methods, such as conditional autoregressive value at risk (CAViaR) and conditional autoregressive expectile (CARE) methods, and a Gaussian quasi-maximum likelihood estimator (QMLE)-based method through back-testing methods. We use unconditional coverage (UC) and conditional coverage (CC) tests for VaR, and a bootstrap test for ES to check the adequacy. A real data analysis is conducted for S&P 500 index and Hyundai Motor Co. stock price index data sets.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.4
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• pp.57-62
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• 2005

Satellite contamination from back-scattered molecules has long been analyzed using the BGK theory or the DSMC technique which are rather inefficient in that they are complicated or take a long time in the analysis. This study presents a new technique of estimating the back-scattering contamination, which is very simple and easy to use like the view factor method and also very accurate. This method, called the modified view factor method, is equivalent to the DSMC in so far as the molecular thermal velocity is much smaller than the satellite velocity and the mean free path much longer than the satellite.

• Journal of the Korean Institute of Intelligent Systems
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• v.9 no.5
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• pp.490-495
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• 1999

In this paper. a learning method VoD-EBP for neural networks is proposed, which learn patterns by error back propagation. Based on Voronoi diagram, the method initializes the weights of the neural networks systematically, wh~ch results in faster learning speed and alleviated local optimum problem. The method also shows better the reliability of the design of neural network because proper number of hidden nodes are determined from the analysis of Voronoi diagram. For testing the performance, this paper shows the results of solving the XOR problem and the parity problem. The results were showed faster learning speed than ordinary error back propagation algorithm. In solving the problem, local optimum problems have not been observed.

• International Journal of Korean Welding Society
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• v.1 no.2
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• pp.51-60
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• 2001

A prediction method for determining the welding residual stress by artificial neural network is proposed. A three-dimensional transient thermo-mechanical analysis has been performed for the $CO_2$ arc welding using the finite element method. The first part of numerical analysis performs a three-dimensional transient heat transfer analysis, and the second part then uses the results of the first part and performs a three-dimensional transient thermo-elastic-plastic analysis to compute transient and residual stresses in the weld. Data from the finite element method are used to train a back propagation neural network to predict the residual stress. Architecturally, the fully interconnected network consists of an input layer for the voltage and current, a hidden layer to accommodate the failure mechanism mapping, and an output layer for the residual stress. The trained network is then applied to the prediction of residual stress in the four specimens. It is concluded that the accuracy of the neural network predicting method is fully comparable with the accuracy achieved by the traditional predicting method.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.6
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• pp.528-538
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• 2011

As a forming method for curved hull plates more efficient than the flame bending, mechanical bending using multi point press forming and die-less forming is discussed in this paper. the mechanical forming is a flexible manufacturing system for automatically forming of hull parts. It is especially suited to varied curved parts. This paper discusses a multiple point pressing machine composed of a pair of reconfigurable punches in order to achieve the rapid forming of curved hull plates using division forming and presents how forming information is obtained from the given design surface. Although the mechanical forming can be efficient in the metal forming, spring back after pressing is a phenomenon which must be carefully considered when quantifying the process variables. If the spring back is not accurately controlled, the fabricated shell plate cannot meet assembly tolerance. This paper describes the principles to calculate the proper stroke of each punch at the divided areas. the strokes are determined by an iterative process of sequential pressing and spring back compensation from an unfolded flat shape to its given design surface. FEA(finite element analysis) is used to simulate the spring back of the plate and the IDA(iterative displacement adjustment) method adjusts the offset of pressing punches from the deformation results and the design surface. The shape deviations of two surfaces due to spring back are compensated by integrated system using FEA and IDA method. For the practical application, It is aimed to develop an integrated system that can automatically perform the compensation process and calculate strokes of punches of the double sides' reconfigurable multiple-press machine and some experimental results obtained with mechanical bending are presented.

• Journal of Korean Medicine Rehabilitation
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• v.32 no.1
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• pp.51-62
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• 2022

Objectives Objective of this study is to investigate the role of paraspinal muscles by examining the correlation between slip percentage (SP) of spondylolisthesis and fatty infiltration of lumbar paraspinal muscle. Methods Retrospective analysis was performed on 45 patients diagnosed with spondylolisthesis based on medical records. Using T2-weighted axial magnetic resonance imaging, cross-sectional areas (CSAs) of psoas major (PM), multifidus (MU) and erector spinae (ES) were calculated and divided by CSA of lower level vertebral body (VB). SP was measured using sagittal T2-weighted images. Correlation of SP with muscle relative cross-sectional area (RCSA) and muscle fatty infiltration by Goutallier classification was respectively analyzed using Spearman correlation. Statistic assessment conducted by Wilcoxon signed rank test and paired t-test using program GraphPad prism 5 (GraphPad Software, Inc., San Diego, CA, USA). Results Spondylolisthesis forward slip percentage by Taillard's method was negatively associated with both side MU RCSAs. No significant correlation was found between PM RCSA, ES RCSA and SP. Forward slippage was significantly correlated with fatty infiltration of lumbar paraspinal muscle measured by Goutallier classification. Conclusions This study is to understand the role of paraspinal muscle affecting spinal instability by investigating correlation between statistical deviation of lumbar muscle characters (RCSA, fatty infiltration of lumbar muscle) and SP. We found that spondylolisthesis SP is positively related to fatty infiltration of lumbar paraspinal muscle. and is negatively associated with both side MU RCSAs.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2293-2298
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• 2007

In this study, a dithizone extraction technique involving purge & trap GC-MS was developed for the determination of methylmercury in biological samples, especially blood and fish. After alkaline digestion, methylmercury in biological samples was extracted into dithizone and back-extracted into aqueous sulfide solution. The extracted methylmercury was converted to the volatile ethyl derivative, purged and trapped onto a solid-phase collection medium, and then introduced into the GC-MS system. The determined MDLs of the established method were 0.9 ng·g?1 for biological samples and its accuracy and precision were found to be 93% and 3.8%, respectively. The method was validated by analysis of CRMs such as SRM 966, BCR 463 and IAEA 407 and all analytical results were within certified ranges with average RSDs of less than 6%. The analytical results of field-sampled fish also showed that the method can be successfully used as an alternative for commonly used distillation method followed by GC-CVAFS detection.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.5 s.149
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• pp.529-537
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• 2006

International Maritime Organization (IMO) is planning to include the Alternative Assessment of the Weather Criterion in the new Intact Stability (IS) Code to be revised. In this study, the procedure of the model test in the Interim Guidelines was reviewed by carrying out the model test and analyzing the test results. For this purpose, RO/RO passenger ship whose ratios of breadth to draft and the height of weight to draft were above 3.5 and above 0.6 respectively was selected as a test ship. Drifting test and motion test in regular waves were performed to estimate the hydrodynamic heeling lever and roll-back angle. Motion tests in waves were carried out in the three wave steepness conditions to measure roll-back angle and examine the feasibility of so called, the Three-step method. Using the test data, satisfaction of the Weather Criterion was assessed for the test ship by using the alternative method and compared with the current method.