• Title/Summary/Keyword: COEFFICIENT OF VARIATION

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Measurement of Hardness and Adhesiveness of Cooked-Rice (밥블록을 이용한 찰밥의 경도 및 부착성 측정법)

  • Lee, Y.J.;Hwang, S.W.;Park, Y.S.;Yoon, W.J.;Chun, J.K
    • Applied Biological Chemistry
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    • v.38 no.5
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    • pp.398-402
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    • 1995
  • Hardness and adhessiveness of cooked rice were measured with rice grain and rice block methods by texturemeter. In grain method 3, 4 and 5 grains were arranged and subjected to the texture test with a plastic plunger at 95% strain and 0.5mm/sec speed. The hardness were 7.4kg, 7.5kg and 10.0kg respectively and the coefficient of variation ranged from 37.0% to 25.9%, which was mainly due to the irregular geometry of the grains in each specimen set Adhesiveness could not be measured with this method. A cylindrical rice block($H/D=20mm{\times}15mm$) was made for the texture analysis. The hardness was 2.1 kg with coefficient of variation ranging from 2.8 to 7.0%, and the block method was s more reproducible compared to the grain method. A grooved plastic plunger and platform were designed for the measurement of adhesiveness of cooked rice block. The adhesiveness was 0.68kg sec and the coefficient of the variation was 4.6%.

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A study on failure probability characteristic based on the reliability analysis according to the variation of boundary conditions (신뢰성 기반 쉴드터널의 경계조건 변화에 따른 파괴확률 특성에 관한 연구)

  • Gyu-Phil Lee;Young-Bin Park
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.6
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    • pp.447-458
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    • 2023
  • In this study, a comparison model considering the stochastic characteristics of the load and member resistance of the shield tunnel segment lining as well as the variability of the boundary condition was selected and reliability analysis was performed, and the adequacy of the limit state design was analyzed by calculating the probability of failure and reviewing the structural safety. For the analysis considering the probability characteristics of these ground constants, the ground spring coefficient was considered as the mean value by calculating the quantitative value by applying the Muirwood formula, and the coefficient of variation was selected based on the existing research data to review the models according to the change of ground boundary conditions. Through the structural analysis of these models and the reliability analysis using MCS technique, the failure probability and reliability index were calculated to examine the changes in the failure probability due to changes in ground boundary conditions.

Understanding Distributional Attributes of Rural Amenity Resources using Gini's Coefficient (지니계수를 통한 농촌어메니티 자원 집중화 연구)

  • Lee, Sang-Hyun;Choi, Jin-Yong;Oh, Yun-Gyeong;Bae, Seung-Jong
    • Journal of Korean Society of Rural Planning
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    • v.16 no.2
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    • pp.57-64
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    • 2010
  • This study aims to understand the degree of inequality of surveyed amenity resources and identify which resource and region have the highest concentration by estimating Lorenz Curve and the Gini's Coefficient. The Lorenz Curve and Gini's Coefficient derived from economics are introduced as tools for investigating and quantifying regional variability of amenity resources concentration. This study describes the concepts underlying the application of the Gini's coefficient to measure the concentration of amenity resources in 11 regions, Chungbuk Province, Korea. The Lorenz Curve presents a graphical view of the cumulative distribution of amenity resources and the Gini's Coefficient provides a single-parameter measure of the distributional concentration of amenity resources. Also the Gini's Coefficient is compared to the number of amenity resource for understanding distributional difference between concentration and quantitative distribution of amenity resources. The results demonstrate significantly different regional variation according to the amenity variables: almost intact nature, interaction between nature and man, man-made.

A Numerical Study on the Effects on Consolidation Settlement Behavior due to Uncertainty of Compression Index (압축지수의 불확실성이 압밀침하 거동에 미치는 영향에 대한 수치적 평가)

  • Byun, Yoseph;Kim, Kwangyoon;Lee, Changki;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.11
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    • pp.43-50
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    • 2012
  • In this research, the value of consolidation index was investigated. The range of the investigated standard deviation was analyzed and the deviation based settlement was calculated. Also, the compression index, which is the effect of the uncertainty in the ground was analyzed using the flimsy ground construction method. The settlement behavior in each embankment compaction stage was analyzed by applying the precompression load method, drainage expediting method, and displacement method through numerical analysis. In addition to the above, the settlement behavior was studied by analyzing the Piled Raft method which is stable for long term settlement. As a result, the final settlement amount based on average analysis results was that the settlement based on each of the average interpretation value, mean value of the maximum and minimum value and average compression index was different. The result of the comparison shows the difference in variation coefficient by the difference in time. Amongst them, the Piled Raft method shows the most consistent variation coefficient regardless of time and it also was least affected by the compression index of uncertainty.

Variations of Secchi Depth in Coastal Water, Masan Bay in Korea (마산만의 투명도 변동)

  • 염말구;정연수
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.39 no.1
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    • pp.44-49
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    • 2003
  • Masan Bay is one of the most heavily polluted bay in Korea owing to the large industrial complex and urban area. Water transparency, Secchi depth in meter, was observed 33 times totally at four sites during 1995 through 2002 and analysed statistically. The range was 0.2∼7.2m, mean 204m, and variation coefficient 60% in totally. Roughly speaking, monthly mean showed lower value April or July than other months. Seasonal mean showed lower in spring or summer than other seasons. Yearly mean was lowest in '95 and '98 during 7 years. Each sampling site showed a different patterns by the monthly, seasonal or yearly transparencies. Inner bay area, S1 site, showed lowest transparency and highest variation coefficient owing to the streamlets and urban area. And it was supposed that one of the important factor affecting different transparency distribution of most seaward site, S4 site, among four sites in the Masan Bay may be the underwater effluents of urban sewage water treated.

Compression Methods for Time Series Data using Discrete Cosine Transform with Varying Sample Size (가변 샘플 크기의 이산 코사인 변환을 활용한 시계열 데이터 압축 기법)

  • Moon, Byeongsun;Choi, Myungwhan
    • KIISE Transactions on Computing Practices
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    • v.22 no.5
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    • pp.201-208
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    • 2016
  • Collection and storing of multiple time series data in real time requires large memory space. To solve this problem, the usage of varying sample size is proposed in the compression scheme using discrete cosine transform technique. Time series data set has characteristics such that a higher compression ratio can be achieved with smaller amount of value changes and lower frequency of the value changes. The coefficient of variation and the variability of the differences between adjacent data elements (VDAD) are presumed to be very good measures to represent the characteristics of the time series data and used as key parameters to determine the varying sample size. Test results showed that both VDAD-based and the coefficient of variation-based scheme generate excellent compression ratios. However, the former scheme uses much simpler sample size decision mechanism and results in better compression performance than the latter scheme.

Measurements of scattering and absorption coefficients of diffusers with variation of surface area (확산체의 표면적 변화에 따른 흡음 및 확산계수 측정)

  • Kumar P., Senthil;Kim, Yong-Hee;Jeon, Jin-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.983-986
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    • 2007
  • The absorption power of a surface depends on the surface irregularity which has been known as an important factor in determining scattering coefficient. This study investigates the effect of increase in surface area on the absorption and scattering coefficients of a diffuse surface. The surface irregularity or surface pattern can be compared to the wavelengths and the random-incidence scattering coefficient of surface is measured by ISO 17497-1. The scattering coefficients of increasing the surface area in linear pattern of v-cut groove on rubber plate were measured in 1:10 scale model reverberation chamber. It is found that the scattering and absorption coefficients increase with increasing surface area. At 60% of increased surface area the spacing between the hemisphere diffuser and the v-cut groove acts similar with results of absorption coefficient. The results show that absorption coefficient depends on surface area and the spacing where as scattering coefficient depends on surface area and texture.

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Acoustic Absorption Coefficient and Impedance of Wood Sections (목재단면(木材斷面)의 흡음계수(吸音係數)와 음향(音響)임피이던스)

  • Hong, Byung-Wha
    • Journal of the Korean Wood Science and Technology
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    • v.17 no.2
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    • pp.26-33
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    • 1989
  • The acoustic absorption coefficient and acoustic impedance of 5 species of softwood(sonamoo, sam namoo, gusang namoo, hwaback, sitka spruce) and 5 species of hardwood (Mulgusul namoo, Italian popular, white meranti, red meranti, kalantas) were measured by the standing wave method. which is simple in the setup and gives more accurate result than does any other measuring method. The dependence of the absorption coefficient and complex acoustic impedance on the wood sections. thickness of the sample itself and the back air gap was investigated experimentally in the frequency range from 200Hz to 1800Hz, and the result are as follows: 1. The acoustic absorption coefficient of wood sections was higher on the cross section than radial and tangential sections. 2) The acoustic absorption coefficient were higher in the frequency range from 400Hz to 600Hz, but decreased in the frequency above 600Hz. 3. The genenal tendency of the variation of the normal acoustic impedance was increased according to the frequency. 4. The acoustic absortion coefficient was increased in the to 7mm-thick sample and decreased in 9mm-thick sample. 5. The higher acoustic absorption coefficient was shown in the case with the backing an gap than in the case without the gap.

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Variation in Solar Limb Darkening Coefficient Estimated from Solar Images Taken by SOHO and SDO

  • Moon, Byeongha;Jeong, Dong-Gwon;Oh, Suyeon;Sohn, Jongdae
    • Journal of Astronomy and Space Sciences
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    • v.34 no.2
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    • pp.99-103
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    • 2017
  • The sun is not equally bright over the whole sphere, but rather is darkened toward the limb. This effect is well-known as limb darkening. The limb darkening coefficient is defined by the ratio of the center intensity to limb intensity. In this study, we calculate the limb darkening coefficient using the photospheric intensity estimated from solar images taken by solar and helispheric observatory (SOHO) and solar dynamics observatory (SDO). The photospheric intensity data cover almost two solar cycles from May 1996 to December 2016. The limb darkening coefficient for a size of 0.9 diameter is about 0.69 and this value is consistent with solar limb darkening. The limb darkening coefficient estimated from SOHO shows a temporal increase at solar maximum and a gradual increase since the solar minimum of 2008. The limb darkening coefficient estimated from SDO shows a constant value of about 0.65 and a decreasing trend since 2014. The increase in the coefficient reflects the effect of weakened solar activity. However, the decrease since 2014 is caused by the aging effect.

A Study on Gas Transfer of Viscous Aqueous Solutions in a Bubble Column (기포탑에서 점성수용액의 가스전달에 관한 연구)

  • 최일곤;김상렬
    • Journal of the Korean Society of Safety
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    • v.9 no.3
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    • pp.67-73
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    • 1994
  • The gas holdup and volumeteric liquid phase mass transfer coefficient with the variation of the concentration of CMC aqueous solution, gas velocity, diameter and area of the draught tube were investigated. As the results of the experiments, the gas holdup and volumetric liquid phase mass transfer coefficient decreased with decreasing the concentration of CMC aqueous solution, increased with increasing the gas velocity and increased with increasing the circulated area ratio of the draught tube.

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