• Bulletin of the Society of Naval Architects of Korea
• /
• v.24 no.4
• /
• pp.45-52
• /
• 1987

In this paper, merits and demerits of Nelder and Mead Penalty Function Method(SUMTNM) and Flexible Tolerance Method(FTM) are investigated from the standpoint of generality, accuracy and efficiency. SUMTNM is combined with Nelder and Method and SUMT, but FTM improves the values of the objective function by using information provided by feasible points as well as certain nonfeasible points termed near-feasible points. Therefore, FTM uses more information than SUMTNM for minimizing object function. The structural analysis of a vertically corrugated bulkhead is performed by collapse mechanism and plate buckling analysis. Based on the results of this analysis, minimum structural weight design of a corrugated bulkhead by use of above two optimization techniques is carried out by investigating the effects of sizes of bulkhead on the structural weight.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.3
• /
• pp.52-57
• /
• 2000

This study intends to reduce the weight of structure without changing the dynamic characteristics. At first, the Vibration analysis by the Substructure Synthesis Method and FFM using the ANSYS are performed for the engine speed converter to confirm the reliability of the analyzing tools. Weight minimization is performed by the Sensitivity Analysis and the Optimum Structural Modification. To decrease the converter weight ideally, the parts with low sensitivity are to be cut mainly, and the changing quantity of the natural frequency by the cut is to be recovered by the weight modification of the parts with high sensitivity. As the unique mathematical solution for the homogeneous problem(i.e. 0 object function problem) does not exist, the converter is redesigned with much thinner initial thickness. The goal of this study is to recover the dynamic characteristics of redesigned structure to those of the original one. To say in the other words, the modified structure has the same dynamic characteristics and the more lighter weight to compare with the original one.

• Structural Engineering and Mechanics
• /
• v.55 no.4
• /
• pp.885-900
• /
• 2015

This paper introduces Romberg-Richardson's method as one of the numerical integration tools for computation of stress intensity factor in a pre-cracked specimen subjected to a complex stress field across the crack faces. Also, the computation of stress intensity factor for various stress fields using existing three methods: average stress over interval method, piecewise linear stress method, piecewise quadratic method are modified by using Richardson extrapolation method. The direct integration method is used as reference for constant and linear stress distribution across the crack faces while Gauss-Chebyshev method is used as reference for nonlinear distribution of stress across the crack faces in order to obtain the stress intensity factor. It is found that modified methods (average stress over intervals-Richardson method, piecewise linear stress-Richardson method, piecewise quadratic-Richardson method) yield more accurate results after a few numbers of iterations than those obtained using these methods in their original form. Romberg-Richardson's method is proven to be more efficient and accurate than Gauss-Chebyshev method for complex stress field.

• International Journal of Precision Engineering and Manufacturing
• /
• v.8 no.3
• /
• pp.60-63
• /
• 2007

Weight functions in fracture mechanics represent the stress intensity factors as weighted averages of the externally impressed boundary tractions and body forces. We extended the weight function theory for cracked linear elastic materials to calculate the notch stress intensity factor of a notched structure with anti-plane deformation. The well-known method of deriving weight functions by differentiation cannot be used for notched structures. By combining an appropriate singular field with a regular field, we derived weight functions for the notch stress intensity factor. Closed expressions of weight functions for notched cylindrical bodies are given as examples.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.3 no.3
• /
• pp.59-66
• /
• 1980

The purpose of this paper to study on measuring method in technical progress. Technology is combination method of raw material and capital, land, labour. The first step to technical Progress is COBB-DOUGLAS production function, so technical progresses are important role in economic growth and development. General production function from Y=f(K, L, T) and COBB-DOUGLAS production function Y=${AK^I}{L^b}$ is first condition. Technical progress is saving of production factor In capital saving, labour saving, neutral saving. Marred Hicks Robinson has Insist on technical progress by each view of production factor, but, what is most excellent measuring method of technical progress\ulcorner I : productivity index method. II : Gross Production function method. Productivity method used in every products level in weight values, gross method function method used in production factor attributed to products. Above two measuring method has delicate problem in each input factor, substitution relation and production factor simultaneously linked each others This basic problem based on technical progress is not solubable in this time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.10
• /
• pp.702-709
• /
• 2008

In this paper, the optimal thermal storage time of an air-conditioning system with slab thermal storage in office building was analyzed on the basis of the gradient method algorithm. The sum of room temperature deviation and heat extraction rate was set to the criterion function. It was calculated that four hours is the optimal thermal storage time under the standard evaluation criterion. Furthermore, some case studies were executed by controlling ratio of weight functions of room temperature deviation and heat extraction rate in criterion function. It is possible to design many kinds of optimal operation of an air-conditioning system with slab thermal storage by controlling ratio of the weight functions in criterion function.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.30 no.4
• /
• pp.1-9
• /
• 2002

There is the high possibility of crack initiation from mechanical joints, which are widely used in aircraft fuselages, due to the development of stress concentration and contact pressure. In this paper, the mixed-mode stress intensity factors at the surface and deepest points of an inclined quarter elliptical corner crack in mechanical joints are analyzed by the weight function method. The coefficients included in the weight function are obtained by finite element analyses for reference loadings. Critical angle at which mode I stress intensity factor becomes maximum is determined by analyzing the variation of stress intensity factors along incline angle of crack and the effects of the amount of clearance and crack depth on the critical angle are investigated.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.2
• /
• pp.412-434
• /
• 2023

This study discusses the high-order diffusion method in the wavelet domain. It aims to improve the edge protection capability of the high-order diffusion method using wavelet coefficients that can reflect image information. During the first step of the proposed diffusion method, the wavelet packet decomposition is a more refined decomposition method that can extract the texture and structure information of the image at different resolution levels. The high-frequency wavelet coefficients are then used to construct the edge detection function. Subsequently, because accurate wavelet coefficients can more accurately reflect the edges and details of the image information, by introducing the idea of state weight, a scheme for recovering wavelet coefficients is proposed. Finally, the edge detection function is constructed by the module of the wavelet coefficients to guide high-order diffusion, the denoised image is obtained. The experimental results showed that the method presented in this study improves the denoising ability of the high-order diffusion model, and the edge protection index (SSIM) outperforms the main methods, including the block matching and 3D collaborative filtering (BM3D) and the deep learning-based image processing methods. For images with rich textural details, the present method improves the clarity of the obtained images and the completeness of the edges, demonstrating its advantages in denoising and edge protection.

• The Journal of Pediatrics of Korean Medicine
• /
• v.19 no.2
• /
• pp.243-253
• /
• 2005

Objective : In this study we aimed to· investigate the parental recognition on Herbal Medication. The result showed that parents concerned about the effect of Herbal Medication on liver function and gaining weight. Therefore, we had a retrospective study on the effect of Herbal Medicaion on liver function and gaining weight. Method : In parent's recognition study, we surveyed 354 parents of children who make a first visit to Department of Oriental Pediatrics in ${\bigcirc}{\bigcirc}$ Medical Center from 3 October to 2 November 2005. In retrospective study, we examined medical record of 22 children who visited to Department of Oriental Pediatrics in Kyunghee Medical Center from 30 September 2005 to 1 January 2005. Height, weight, BMI, body fat mass, body fat ratio, AST and ALT were estimated at two points; before and after Herbal Medicaion treatment. Result: The mean of expectation of parents on the efficacy of Herbal Medication was 75.14 on the VAS scale, which was interpreted as significantly high. The result showed the effect of Herbal Medicaion on liver function(48%) and gaining weight(53%) took the largest portion. When we observe the effect of Herbal Medication on Liver function, after Herbal Medication treatment we have slightly increased AST and slightly decreased ALT, but they were not statistically significant. Also we observe the effect of Herbal Medication on getting obesity after Herbal Medication treatment. The result showed that we have slightly decreased BMI, body fat mass, body fat ratio, but they were not statistical1y significant. Conclusion : Our report shows parents of children have high expectation and stand favorable on the efficacy of the Herbal Medication. We found that parents concerned the most about the effect of Herbal Medicaion on liver function and gaining weight. Our retrospective study showed that Herbal Medicaion treatment on children has relationship with neither liver function nor the degree of obesity.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.12
• /
• pp.3136-3148
• /
• 1994

This paper proposed the method of fracture integrity evaluation for semi-elliptical crack. Plane strain fracture toughnesses are used to compare with the thermal shock stress intensity factors for semi-elliptical crack obtained by Vainshtok weight function method. The method is applied to the finite Cr Mo V and 2.25Cr Mo steel plates with semi-elliptical crack under the thermal shock. For the purpose, tensile property and fracture toughness with respect to the temperature are measured. To verify the method, thermal shock experiments are carried. The theoretical predictions are in good agreement with the experiments.