• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.211-216
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• 2006

Monitoring variability is a vital part of modem statistical process control. The conventional Shewhart Rand S charts address the setting where the in-control process readings have a constant variance. In some settings, however, it is the coefficient of variation, rather than the variance, that should be constant. This paper develops a chart, equivalent to the S chart, for monitoring the coefficient of variation using rational groups of observations.

• Korean Journal of Mathematics
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• v.24 no.1
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• pp.1-13
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• 2016

This paper shows that the solutions to the perturbed functional dierential system $$y^{\prime}=f(t,y)+{\int_{t_0}^{t}}g(s,y(s),Ty(s))ds$$ have uniformly Lipschitz stability and asymptotic property. To sRhow these properties, we impose conditions on the perturbed part ${\int_{t_0}^{t}}g(s,y(s),Ty(s))ds$ and the fundamental matrix of the unperturbed system $y^{\prime}=f(t,y)$.

• Transactions of Materials Processing
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• v.13 no.2
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• pp.180-187
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• 2004

A computer code was developed to simulate the filling stage of the injection/compression molding process by a finite element method. The constitutive equation used here was the compressible Leonov model. The PVT relationship was assumed to follow the Tait equation. The flow-induced birefringence was related to the calculated flow stresses through the linear stress-optical law. Simulations of a disk part under different process conditions including the variation of compression stroke and compression speed were carried out to understand their effects on birefringence variation. The simulated results were also compared with those by conventional injection molding.

• Journal of the Chungcheong Mathematical Society
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• v.29 no.3
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• pp.429-442
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• 2016

In this paper we show that the solutions to the perturbed differential system $$y^{\prime}=f(t,y)+{\int}_{to}^{t}g(s,y(s),Ty(s))ds$$ have uniformly Lipschitz stability and asymptotic behavior by imposing conditions on the perturbed part $\int_{to}^{t}g(s,y(s),Ty(s))ds$ and the fundamental matrix of the unperturbed system y' = f(t, y).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.16-25
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• 1995

The effects of leaf removal time on variation of nodal sink components in determinated soybean ［Glycine max （L.） Merr.］ cultivar 'Danyeobkong' were measured at the experiment field of Chonbuk Provincial Rural Development Administration in 1991. Node order in this experiment was calculated from terminal node to bottom node to clarify the photosynthetic ability of canopy leaves. The upper 5 leaves from terminal node of main stem were removed at 5, 15, 25, 35 and 45 days after flowering(DAF) respectively. In spite of light-receiving increment in lower part of main stem and in branch by removing the upper part leaves of main stem, seed weight of that part was not increased in leaf removal treatment compared with control block. The node position reducing pod went down from terminal to bottom by delaying leaf removal time, and the influence of pod number reduction was bigger in DAF 25 than in DAF 15. But the seed number reduction per pod was the biggest in DAF 35. Cracked seed coat ratio ranged from 25% to 35% in control block, while that of leaf removal block had mostly 10% gap compared with the control block.rol block.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.4
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• pp.85-95
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• 2007

The variation of hydraulic and hydrologic aspect of urban area according to the strongly seasonal variation of rainfall and the increment of urbanization has caused the runoff variation and increased the flood damage, and thus made a difficulty to manage water resources in urban area. Recently, as a part of efforts to resolve these problems, the facilities for reducing runoff increasing due to urbanization have a tendency to install in our country. In this study, more effective Infiltration-Storage System(ISS) is proposed and its reducing effect is analyzed by hydraulic experimental study. The infiltration characteristics of runoff reduction facilities are examined as varying artificial rainfall and a material of infiltration layers being able to consider the influence of urban development. As a result of comparison of infiltration rate of the upper and lower parts, the infiltration rate in the lower part is larger than that of the upper part. Thus, the ISS is more available than existing runoff reduction facilities. Results obtained in this study can be provided fundamental data for improvement of existing runoff reduction facilities and practical use of ISS.

• Journal of Fashion Business
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• v.7 no.6
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• pp.57-66
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• 2003

With the occurrence of interest in image-presentation that helps express one's individuality in several place in our society, it has affected make-up field. Now, make-up is getting to be recognized as a key role player that reflects our social and cultural concerns not only by presenting a appropriate one that is proper when to use and what for, but also presenting individualistic images that are able to express one's attractiveness free from a last plain concept that meant merely applying cosmetics to one's face is makeup. Like above, the reason that a change for consciousness of the function of make-up was possible is a noticeable outcome that results from the difference before and after make-up. In other word, with the help of Corrective Make-up that makes use of optical illusion, the analytic research for features could have been carried out systematically, therefore, women get to present their beauty of innate facial shape and features at their pleasure. The basic principles of the Corrective Make-up, which was introduced to satisfy the purpose of the existing make-up take advantage of lines and colors that are part of the optical illusion. The nature of direction and movement was expressed by the direction and angle of lines and the colors are also able to induce the variation of images depend on the whole color around them or contrastive color around. This thesis is mainly about optical illusion through lines that are part of elements that induce the optical illusion and deals with phenomena that occur when we apply lines that are part of design into the make-up. And this is written for the purpose of establishing the last basis of make-up more scientifically and systematically through the research for the variation when we apply the nature of lines into our features and deriving facial image variation from it. This is also for study into the role of make-up as for psychological effect that is able to make facial images look different when the optical illusion with possible visual errors is applied into it. In conclusion, we can say "Make-up is optical illusion through visual elements such as lines, surfaces, books, touch and so on."

• Advances in Computational Design
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• v.4 no.1
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• pp.43-52
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• 2019

Variation Analysis (VA) is used to simulate final product variation, taking into consideration part manufacturing and assembly variations. In VA, all the manufacturing and assembly processes are defined at the product design stage. Process Capability Data Bases (PCDB) provide information about measured variation from previous products and processes and allow the designer to apply this to the new product. A new challenge to this traditional approach is posed by the Industry 4.0 (I4.0) revolution, where Smart Manufacturing (SM) is applied. The manufacturing intelligence and adaptability characteristics of SM make present PCDBs obsolete. Current tolerance analysis methods, which are made for discrete assembly products, are also challenged. This paper discusses the differences expected in future factories relevant to VA, and the approaches required to meet this challenge. Current processes are mapped using I4.0 philosophy and gaps are analysed for potential approaches for tolerance analysis tools. Matching points of simulation capability and I4.0 intents are identified as opportunities. Applying conditional variations, incorporating levels of adjustability, and the un-suitability of present Monte Carlo simulation due to changed mass production characteristics, are considered as major challenges. Opportunities including predicting residual stresses in the final product and linking them to product deterioration, calculating non-dimensional performances and extending simulations for process manufactured products, such as drugs, food products etc. are additional winning aspects for next generation VA tools.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.8-14
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• 2023

This study was conducted to develop a precision automatic irrigation system in a nursery by considering the problems and improvements of manual and the conventional automatic irrigation system. The amount of irrigated water between the conventional automatic irrigation system and manual irrigation was 28.7 ± 4.4 g and 14.2 ± 4.3 g, respectively, and the coefficient of variation was less than 30%. However, the coefficient of variation of the conventional automatic irrigation system of 15%, was higher than that of manual irrigation of 30%. The irrigation test using the developed uniform irrigation system attached with the nozzle of a spray angle 80° and most highest uniformity was at height 600 mm. And coefficient of variation of the irrigation uniformity at the center part was within 20%, but irrigation amount of the edge part was lower 50% and over compared to the center part. As a result of a tomato grafting seedling cultivation test using the developed uniform irrigation system, the average plant height of seedling at the edge part was 28 mm but plant height at the center part was higher as 72 mm. Therefore, it was necessary to apply additional irrigation device at the edge part. The irrigation uniformity of the edge concentrated irrigation system was investigated that the irrigation amount of the edge part was irrigated by more than 50% compared with the center part, and coefficient of variation of the irrigation amount at the center part was less than 30%. As a result of a cucumber grafting seedling cultivation test using the edge concentrated irrigation system, the plant height of seedlings in the edge and central part of cultivation bed were 24% and 26%, respectively, so irrigation uniformity was higher then the uniform irrigation system. In order to improve the uniformity of seedlings, it is necessary to adjust the height of boom according to the growth of the seedling by installing a distance sensor in the overhead watering and boom irrigation system.

• Economic and Environmental Geology
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• v.31 no.1
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• pp.59-68
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• 1998

Gravity, magnetic and VLF surveys were carried out to investigate the dimension, nature and stability of the waste materials filled in the Seokdae landfill, Pusan. The Seokdae landfill, which is located in a former valley, was used as a dump for mainly domestic-type waste materials for 6 years from 1987. The landfill site is classfied into A, B, C and D areas according to the sequence of dumping period. The Bouguer gravity anomaly map shows maximum variation of 3.1 mgals on the landfill and its general appearance has close relation with the thickness of waste filled. The local variation of anomaly, however, reflect the degree of compactness of waste materials which may be affected by the nature of waste and dumping time. In the case of area A, where dumping process was terminated at the very last stage, most part show negative anomaly compared to other areas. We think that the composition of the waste materials in the area A is high in leftover food and paper trash and they are still in uncompacted condition. In area B, the general trend of variation of gravity anomaly is appeared to be high anomaly in northern part and decrease to the southern part. This is well matched with the prelandfill topography of the landfill site. The southern part of area B is located in the center of valley and its present surface is comparatively rugged, which may be due to the differential settlement of deep burried waste. The thickness of waste in area C is relatively thin, but the gravity anomaly appears to be low. Considering the present condition of surface, it can be inferred that low density wastes such as leftover food were mainly filled in this area. Area D, as in the case of area B, shows gravity anomaly that has close relation with the prelandfill topography. Magnetic data show the variation of total field intensity varies in the range of 46600~51000 nT, and reach maximum anomaly of 4400 nT. The overall pattern of magnetic anomaly well reflects the distribution of magnetic materials in the landfill. The result of VLF survey reveals several low resistivity zones, which may serve as underground passages for contaminant flow, in the area C located near the small Village.