• Nuclear Engineering and Technology
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• v.36 no.3
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• pp.210-218
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• 2004

In the interest of nuclear power plant safety, a self-diagnostic monitoring system (SDMS) is needed to monitor defects in safety-related components. An air-operated valve (AOV) is one of the components to be monitored since the failure of its operation could potentially have catastrophic consequences. In this paper, a model of the AOV is developed with the parameters that affect the operational characteristics. The model is useful for both understanding the operation and correlating parameters and defects. Various defects are introduced in the experiments to construct a fault library, which will be used in a pattern recognition approach. Finally, the validity of the fault library is examined.

• Journal of the Optical Society of Korea
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• v.19 no.5
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• pp.456-466
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• 2015

We investigated an anti-aliasing (AA) filter for digital camera photography by which the excessively high-frequency components of the image signal are suppressed to avoid the aliasing effect. Our optomechanical AA filter was implemented by applying rapid relative motions to the imaging sensor. By the engineered motion blur of the mechanical dithers, the effective point-spread function (PSF) of the imaging system could be tailored to reject the unwanted high-frequency components of the image. For optimal operations, we developed a spiral filter motion protocol that could produce a Gaussian-like PSF. We experimentally demonstrated that our AA filter provides an improved filtering characteristic with a better compromise of the rejection performance and the signal loss. We also found that the pass band characteristic can be enhanced further by a color-differential acquisition mode. Our filter scheme provides a useful method of digital photography for low-error image measurements as well as for ordinary photographic applications where annoying $moir{\acute{e}}$ patterns must be suppressed efficiently.

• IE interfaces
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• v.12 no.1
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• pp.150-157
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• 1999

Mini-Mill process has been recently in operation at Pohang steel company, which enables more flexible steel coil production on customer demands. The effects of process parameters in Mini-Mill process need to be analyzed not only to make the process stable but also to improve product quality. This work aims to develop a regression model of Mini-Mill process using accumulated product data such that the process parameter effects on product tensile strength may be analyzed. The analysis shows that tensile strength is influenced mainly by the amount of components such as carbon, manganese, silicon, and sulfur. The effect of temperature is shown to be small. It is concluded that control of the components is much more responsible for both meeting the target and reducing the variation of the product tensile strength. Heat treatment is more useful in compensating tensile strength variations due to thickness differences and improving workability and other quality characteristics. More work is necessary for establishing regression expressions of the process that is reliable and accurate enough to dispense with the off-line inspection of the product tensile strength.

• Structural Engineering and Mechanics
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• v.39 no.5
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• pp.643-659
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• 2011

The design of box girders requires the determinations the buckling stress of the flange and the webs. Existing design equations available in codes of practice ignore the interactions between the box girder components. The paper illustrates the influence of the geometric interaction on the buckling stress of box girders. Generalized equations are first derived in terms of the web the flange geometric properties. Industrial examples are then presented showing the variation of the flange buckling stress for various stiffening configurations. The influence of the flange/web proportions on the buckling stress of box girder components is also highlighted. It is shown that buckling strength of the flange is largely affected by the restraints imposed by the webs or attached diaphragms. Graphs are presented showing various limiting states of box girders. These graphs are useful to use in practice in order to achieve economical and efficient design of box girders and rationally predict local buckling stress.

• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.485-492
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• 2014

In baseball, the traditional measure of pitchers are wins and ERA. But these statistics are influenced by luck or team power. So sabermetrician proposes a number of indicators that predict future performance. We determine a new measure, which we call pitching grade index (PGI) that efficiently summarizes a pitcher's performance on a numerical scale using principal components analysis. The PGI statistic can often be useful to assessing a pitcher's individual contribution. Also K-means clustering algorithm are used for segmentation of players into groups.

• Communications for Statistical Applications and Methods
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• v.23 no.3
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• pp.231-239
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• 2016

A graphical diagnostic method based on multiple case deletions in a regression context is introduced by using the sampling distribution of the difference between two least squares estimators with and without multiple cases. Principal components analysis plays a key role in deriving this diagnostic method. Multiple case deletions of test statistic are also considered when a new observation is fitted to a given regression model. The result is useful for detecting influential observations in econometric data analysis, for example in checking whether the consumption pattern at a later time is the same as the one found before or not, as well as for investigating the influence of cases in the usual regression model. An illustrative example is given.

• Korean Journal of Organic Agriculture
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• v.8 no.2
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• pp.79-87
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• 2000

This experiments was carried out to find the effect of different organic farming types, the Duck-pasture plot, the Pond-snail pasture plot andd control of the conventionalculture plot farming on the yield and its components of paddy rice. The results obtained are summarized as follows. Plant height an Tillering were significantly increase in the Duck-pasture plot. Panicle number pr hill, NO. of grain per spike and 1,000grain weight were significantly increase in the conventional culture plot. Yield pre 10a were 574.13kg at pond-snail pasture plot, 576.81kg at Duck-pasture plot and 579.04kg at conventional culture plot. From these results, it seems that the organic farming are useful and pasture of the Duck, Pond-snail for depression of the weed occurrence or increase of yield per 10a is effective as the environmental perservation farming.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1153-1160
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• 2022

The application of video processing techniques are useful for the safety of nuclear power plants by tracking the people online on video to estimate the dose received by staff during work in nuclear plants. Nuclear reactors remotely visually controlled to evaluate the plant's condition using video processing techniques. Internal reactor components should be frequently inspected but in current scenario however involves human technicians, who review inspection videos and identify the costly, time-consuming and subjective cracks on metallic surfaces of underwater components. In case, if any frame of the inspection video degraded/corrupted/missed due to noise or any other factor, then it may cause serious safety issue. The problem of missing/degraded/corrupted video frame estimation is a challenging problem till date. In this paper a systematic literature review on video processing techniques is carried out, to perform their suitability analysis for NPP applications. The limitation of existing approaches are also identified along with a roadmap to overcome these limitations.

• Korean Journal of Plant Resources
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• v.26 no.6
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• pp.718-725
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• 2013

Components extracted from 7 species and 18 populations of Chrysosplenium in Korea were compared and analyzed using GC-MS analysis. 57 components (${\geq}80%$ quality) were identified, of which neophytadiene, palmitic acid and phytol were found at all the taxa. Percentage composition of isolated extracts showed a clear difference in components type and GC-MS profile. On the basis of that result, data matrix was made and cluster analysis using UPGMA was conducted. From the result of cluster analysis, two groups were recombined; one with alternate leaves comprised C. japonicum in Ser. Alternifolia and C. flagelliferum in Ser. Flagellifera and the other with opposite leaves gradationally comprised C. psuedofauriei in Ser. Sinica, C. ramosum in Ser. Oppositifolia and C. sphaerospermum, C. valdepilosum, C. flaviflorum in Ser. Pilosa. These chemotaxonomic results agreed in general with those of existing studies on external morphology and molecular. In conclusion, chemical composition can be an useful characters in understanding the relation analysis among interspecific and intraspecific complex with the help of cluster analysis of 7 species and 18 populations of Chrysosplenium in Korea.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.520-525
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• 2003

Fast Breeder Test Reactor (FBTR) is a 40MW (thermal) / 13.2MW (electrical), Plutonium - Uranium mixed carbide fuelled, sodium cooled, loop type nuclear reactor operating at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam. Its main aim is to generate experience in operation of fast reactors and sodium systems and to serve as an irradiation facility for development of fuels and structural materials fur fast reactors. Nuclear reactors pose difficulties to the NDT techniques used to monitor the conditions of the internal components. Sodium cooled fast breeder reactors have their own typical difficulties in using the NDT techniques. These are due to the need for operation in aggressive environment of nuclear radiation and sodium (molten/vapour), as well as the need to maintain leak tightness of a very high order during all states of reactor operation and shutdown for fuel handling, maintenance and remote inspection. This paper discusses the following NDT techniques, which have been successfully used for the past 15 years in FBTR: (i) Periscope and Projector, (ii) Core Co-ordinate Measuring Device and, (iii) Optical fiberscope. The inspection using these techniques have given confidence for further reactor operation at high power by giving useful data on the conditions of the components inside the reactor vessel.