• International Journal of Korean Welding Society
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• v.4 no.1
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• pp.23-29
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• 2004

In weaving welding where a V groove exists, the heat input distribution is an important factor that determines the defectiveness of the bead shape, undercut and over-lap. In this study, the amount of heat input, which is determined by the welding current, voltage, speed and weaving conditions is calculated through mathematical development and numerical methods. Furthermore, the heat input distribution as a two- dimensional heat source was observed when applied to each groove.

• Transactions of Materials Processing
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• v.24 no.6
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• pp.395-399
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• 2015

A microstructure-based finite element simulation was conducted to predict the plastic strain ratio (R-value) of a dual-phase (DP) steel. The representative volume elements (RVEs) concept was adopted for the image-based FE modeling and a 3D model was constructed using sequential 2D images. Each phase was considered with the von-Mises yield criterion and the Swift model. The Swift parameters were defined by the empirical equations based on the chemical composition. The developed model was applied to analyze the effect of residual stress on the R-value and stress distribution. In order to consider the residual stress development after cold rolling, 10 % compression was applied in the thickness direction and unloaded before the tensile stress was applied in the rolling direction. The results showed a reasonable prediction for the R-value evolution: a sharp increase at small strains was well described and a transition followed in the downward direction. The R-value evolution was analyzed using the stress distribution change on the π-plane

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.179-183
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• 2002

Resonance-enhanced multiphoton ionization with time-of-flight product imaging of the $N(^2D)$ atoms has been used to study the $N_2O$ photodissociation at 118.2 nm and the two-photon dissociation at 268.9 nm. These imaging experiments allowed the determination of the total kinetic energy distribution of the $NO(X^2{\prod})$ and $N(^2D_{5/2})$ products. The $NO(X^2{\prod})$ fragments resulting from the photodissociation processes are produced in highly vibrationally excited states. The two-photon photodissociation process yields a broad $NO(X^2{\prod})$ vibrational energy distribution, while the 118.2 nm dissociation appears to produce a vibrational distribution sharply peaked at $NO(X^2{\prod},\;{\nu}=14)$.

• Asian Journal of Turfgrass Science
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• v.10 no.3
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• pp.247-262
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• 1996

In this study, the distribution of dictyostelid cellular slime molds was investigated from F, H and $A_1$ horizon of pinus, oak forests in Mt. Puk'an, Mt. Nam and Mt. Kwanak. The relationship of cellular slime molds with other soil microorganisms and abiotic factors were analyzed. The six species were isolated as follows: Polysphondlium pallidurn, Dictyostelium purpureum, D. mucoroides, D. crassicaule, D. capitatum, D. implicatum. The dominant species in pinus forests was P. pallidum, and in oak forests it was D. macro ides. In Mt. Nam, D. mucoroides and P. pallidum were isolated at only oak forest. The Correlations of slime mold abundance with bacteria were significant. Even though positive correlations of cellular slime molds with actinomycetes or fungi were not significant, correlations between soil microorganisms were analyzed. Correlation coefficients were high in Mt. Kwanak(r=0.5921) and Mt. Nam(r=0.7243) at significant level P<0.01. There were significant correlations between total slime molds and abiotic factors. It supports that cellular slime molds are limited by foods in nature. In low level of pH, water content and organic matter, that community diversity is more affected by bacteria whose organic degradation capacity is regulated by interactions of soil microorgaisms. Key words: Cellular slime molds, Soil microorganisms, Correlations, Abiotic factors.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.64-68
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• 2010

Recently, MBT(Mechanical Biological Treatment) facilities were built up and operated to separate and recycle MSW(Municipal Solid Wastes)in South Korea. However, the size distribution of MSW is very rough, and it is causing operation problem because MSW would be crushed in undersize diameter by mechanical equipment before feeding each seperation process. Also, the organic material should be pre-seperated to reuse recycle material in MSW. In this research, the reactor of 1ton/batch using the super-heated steam was tested to present the separation efficiency and the size distribution of MSW by experimental factors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.925-926
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• 2008

• The Korean Journal of Applied Statistics
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• v.29 no.2
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• pp.369-379
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• 2016

The Sigma Level, proposed by Motorola Inc., is one of the many Process Capability Index (PCI)'s that have been presented since the 1970's. It is used to evaluate process capability and unlike other PCI's, it has an advantage in that it uses population probability distribution. However, it is originally designed for mass production and is inadequate to evaluate prototypes or early products in the R&D stages. For use in such cases, we propose an R&D target Sigma Level, derived by considering 1.5 sigma shifts in traditional sigma level from a statistical point of view. We also explain the way to find robust limits for design tolerance because the sigma level or defect probability is useful to establish economical tolerance limits at the R&D stage and mass production.

• Communications for Statistical Applications and Methods
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• v.13 no.2
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• pp.243-254
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• 2006

The relative frequency of order statistics is investigated for independent and identically distributed (i.i.d.) random variables. Specifically, it is shown that the probability $Pr\{X_{[s]}=x\}$ is no less than the probability $Pr\{X_{[r]}=x\}$ at any point $x{\geqq}x_0$ when r$X_{[r]}$ denotes the r-th order statistic of an i.i.d. discrete random vector and $x_0$ depends on the population probability distribution. A similar result for i.i.d. continuous random vectors is also presented.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.243-250
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• 1998

This study is to find subjects for the Automated Container Terminal(ACT) development and container terminal system. Also we analyze the present condition of the container terminal system in Pusan port and its automation level by systems approach. And this paper aims at evaluating on the priority of R&D investment until the beginning of the second stage of New Pusan Port Project(2006). In this process we have considered 8 evaluation indexes(cost, labor, area, time, volume, reliability. safety, convenience) to analyze 6 subsystems. The priority of R&D until target year by sub-systems is as follow: 1. Cargo Handing System, 2. Transfer System, 3. Port Entry System, 4. Storage System (Distribution & Manufacturing System included), 5.Inland Transport System, 6.Port Management & Information System.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.42-49
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• 2022

An underground electric switch is a high-voltage switch used in distribution network systems for a reliable power supply. Many studies are being conducted to expand the switch to use an eco-friendly gas using dry air instead of SF6 gas to reduce greenhouse gas emissions. In this study, a flow analysis model was established to improve the performance of an eco-friendly gas switch. The results were compared and reviewed through experiments. For the optimal arc grid design applied to the switch, the flow characteristics based on the flow path configuration and the changes in arcing time for each configuration were compared. Flow analysis can predict the switch flow distribution, and a comparative review of the flow path configurations of various methods is possible.