• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.285-288
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• 2009

The purpose of this study is to predict the forming limit diagram (FLD) of strain-rate sensitive materials on the basis of the Marciniak and Kuczynski (M-K) theory. The strain-rate effect is taken into consideration in such a way that the stress-strain curves for various strain-rates are inputted into the formulation as point data, not as curve-fitted models such as power function. Tensile tests and R-value tests were carried out at several levels of temperature and strain-rate from $25^{\circ}C$ to $300^{\circ}C$ and 0.16 to 0.00016/s, respectively to obtain the mechanical properties of AZ31B magnesium alloy sheet. The FLD of this material was experimentally obtained by limit dome height tests with the punch velocity of 0.1 and 1.0 mm/s at $250^{\circ}C$. The M-K theory-based FLD predicted using Yld2000-2d yield criterion was compared with the experimental results.

• Wind and Structures
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• v.16 no.1
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• pp.47-60
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• 2013

A dominant opening in a windward wall, which generates large internal pressures in a building, is a critical structural design criterion. The internal pressure fluctuations are a function of the dominant opening area size, internal volume size and external pressure at the opening. In addition, many buildings have background leakage, which can attenuate internal pressure fluctuations. This study examines internal pressure in buildings for a range of dominant opening areas, internal volume sizes and background porosities. The effects of background porosity are incorporated into the governing equation. The ratio of the background leakage area $A_L$ to dominant opening area $A_W$ is presented in a non-dimensional format through a parameter, ${\phi}_6-A_L/A_W$. Background porosity was found to attenuate the internal pressure fluctuations when ${\phi}_6$ is larger than 0.2. The dominant opening discharge coefficient, ${\kappa}$ was estimated to lie between 0.05 to 0.40 and the effective background porosity discharge coefficient ${\kappa}^{\prime}_L$, was estimated to be between 0.05 to 0.50.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.4
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• pp.737-740
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• 1992

This study was conducted to demonstrate the practical use of the buffer index curve as a criterion of silage quality evaluation, Forty five samples of the ensiled Italian ryegrass were collected from farms in Okayama, Japan. Silages were devided into 4 groups by the pattern of buffer index curve. Heavy wilting silages (A group) showed no peak on buffer index curve and Flieg's score of 95.6. However, moderate or weak wilting silages (B group) with moisture content of 63.3 showed a peak at pH 4.0 and a Flieg's score of 67.8. Both of A and B groups were regarded as a good quality silage. Silages (C group) with a peak at pH 4.5 were of a medium quality with Flieg's score of 45.3. Poorly preserved silages (D group) with Flieg's score of 12.0 had a peak at pH 5.0. There was a high positive correlationship (p<0.01) between the peak value of buffer index curve and the organic acid content.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.23-27
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• 1990

Adaptive mesh refinement scheme is incorporated with the Boundary Element Method (BEM) in order to get accurate solution with relatively fewer unknowns for the case of magnetostatic field analysis and A new and simple posteriori local error estimation method is presented. The local error is defined as integration over the element of the difference between solutions acquired us ing second order and first order interpolation function and is used as the criterion for mesh refinement at given grid. Case study for two dimensional problems with singular point reveals that meshes are concentrated on the neighbor of singular point and the error is decreased gradually and the solutions calculated on the domain are converged to the analytic solution as the number of unknowns increases. The adaptive mesh gives much better rate of convergence in global errors than the uniform mesh.

• Journal for History of Mathematics
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• v.30 no.4
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• pp.233-246
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• 2017

$Ces{\grave{a}}ro$ summability is a generalized convergence criterion for infinite series. We have investigated the classical results of summability for Fourier series from 1897 to 1957. In this paper, we are concerned with the summability and summation methods for Fourier Series from 1960 to 2010. Many authors have studied the subject during this period. Especially, G.M. Petersen,$K{\hat{o}}si$ Kanno, S.R. Sinha, Fu Cheng Hsiang, Prem Chandra, G. D. Dikshit, B. E. Rhoades and others had studied neoclassical results on the summability of Fourier series from 1960 to 1989. We investigate the results on the summability for Fourier series from 1990 to 2010 in section 3. In conclusion, we present the research minor lineage on summability for Fourier series from 1960 to 2010. $H{\ddot{u}}seyin$ Bor is the earliest researcher on ${\mid}{\bar{N}},p_n{\mid}_k$-summability. Thus we consider his research results and achievements on ${\mid}{\bar{N}},p_n{\mid}_k$-summability and ${\mid}{\bar{N}},p_n,{\gamma}{\mid}_k$-summability.

• Journal of the Korean Society of Industry Convergence
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• v.14 no.3
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• pp.105-111
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• 2011

Landmark Spots in 2D gel electrophoresis are used in many methods of 2DEG spot matching. Landmark Spots are obtained manually and it is a bottle neck in the entire protein analysis process. Automated landmark spots detection is a very crucial topic in processing a massive amount of 2DGE data. In this paper, Automated landmark spot detection is proposed using point pattern matching and graph theory. Neighbor spots are defined by a graph theory to use and only a centered spot and its neighbor spots are considered for spot matching. Normalized Hausdorff distance is introduced as a criterion for measuring degree of similarity. In the conclusion, the method proposed in this paper can get about 50% of the total spot pairs and the accuracy rate is almost 100%, which the requirements of landmark spots are fully satisfied.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.257-266
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• 2011

Recently, the manufacturers of life-jacket are very interested in the acquisition of USCG(US Coast Guard) approval because the acquisition of USCG approval has an important role in the purchasing decision of the buyer's. Be based on criterion of USCG, we studied how to predict the change of floating position of human model with life-jacket to verify the backside restore. For this, in this study, the human model and the lifejacket was modeled in three dimension, the application program for prediction of floating position was developed, and plugged-in commercial program.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.671-676
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• 2005

Spring is one of major suspension part of the light commercial vehicle (LCV). In the manufacturing process it is shot-peened to improve its fatigue strength. In this paper, residual stresses by shot peening were calculated through finite element analysis, and the effects of these residual stresses on fatigue strength of leaf spring were evaluated. Fatigue tests were performed with two kinds of specimens; one is actual leaf spring assembly, and the other is simulated 3-point bending specimen. Fatigue tests were performed under the loading condition that was measured on the proving ground. From the results, the maximum load-fatigue life relation of leaf spring was defined, and test results of 3 point bending specimen are in good agreement with those of leaf spring assembly. The effects of residual stresses by shot peening on fatigue strength of leaf spring is not large in the high load range, however, in the low load range, its effects were not negligible.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.812-815
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• 2005

The incremental forming process employs several tens or hundreds of continuous local strokes, so the entire process is difficult to analyze due to much computation time and large computer memory. The objective of this work is to propose a new numerical scheme of the finite element method, automatic expansion of domain (AED), and to reduce computation time and computer memory. In the AED scheme, an effective analysis domain in each local forming step is defined and then the domain is automatically expanded in accordance with the repeated process. In order to verify the validity of the criterion for the AED scheme and the applicability of the AED scheme, two-dimensional incremental plane-strain forging process is first analyzed using the proposed scheme with various criteria and full domain. In addition, three-dimensional incremental radial forging process is analyzed to verify the applicability of the proposed scheme to a practical incremental forging process.

• Korean Journal of Logic
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• v.13 no.2
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• pp.61-82
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• 2010

The argument from ignorance that knowledge conclusion is derived from ignorance premises is claimed to be fallacious by many logicians such as I. Copi. According to them, some arguments from ignorance which seem to be acceptable are not really the arguments from ignorance. They say that such arguments have implicitly conditional knowledge premise. Against them, I argue that every argument from ignorance can be interpreted as having a hidden conditional premise, and that every argument from ignorance is not fallacious. I propose the criterion to judge which argument from ignorance is fallacious and which is persuasive. In particular, I argue that social contexts play a crucial role to judge whether a practical argument is fallacious or not.