• Journal of Wetlands Research
• /
• v.18 no.1
• /
• pp.39-44
• /
• 2016

The reuse of spent coffee powder has been researched for environmental engineering applications such as adsorbents of organic/inorganic pollutants. In this study adsorption equilibrium tests and adsorption kinetics tests for the removal of aqueous organic pollutant (methylene blue) were conducted using spent coffee powder, granular activated carbon, and powdered activated carbon. It was found that the maximum adsorption capacity of three adsorbents followed the order of powdered activated carbon (178.6 mg/g) > spent coffee powder (60.6 mg/g) > granular activated carbon (15.6 mg/g). The results of adsorption kinetics tests also indicated that spent coffee powder had higher kinetic parameters than granular activated carbon for pseudo 1st and 2nd order kinetics. The high performance of spent coffee powder might be due to its porous surface like those of granular and powdered activated carbons and smaller particle size comparing with granular activated carbon.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.28 no.6
• /
• pp.563-571
• /
• 2010

The GPS satellite has three or four atomic clocks that consist of cesiums and rubidiums and the NANU messages can be used to identify the kind of the onboard atomic clock because they classify the clock type on a daily basis. In this study, for long-term analysis of the GPS satellite clock behavior, we extracted satellite clock errors for every PRN from years 2001 through 2009 using the SP3 files that are provided by the IGS. As a result, the cesium clock offsets usually have a linear trend of drifting. On the other hand, rubidium offsets show curvilinear variations in general, even though they cannot be represented as anyone specific polynomial function. For short-term analysis, we extracted satellite clock errors for each PRN for a week-long period using the CLK files that are also provided by the IGS and curve-fitted them with first-order and second-order polynomial functions. In cases of cesium clock errors, they were well-represented by first-order polynomial functions and rubidium clock errors were similar with second-order polynomials. However, some of rubidium clock errors could not be represented as any polynomial fitting function. To analyze the characteristic of GPS satellite by each block and atomic clock, we applied Modified Allan Deviation criterion to the dataset from years 2007 and 2010. We found that the Modified Allan Deviation characteristics changed significantly according the block and atomic clock type.

• Journal of the Korean GEO-environmental Society
• /
• v.18 no.12
• /
• pp.65-75
• /
• 2017

Flowability and strength with curing time of controlled low-strength material (CLSM) are required differently according to the construction purpose. In this paper, the flowability and strength were estimated from the mixing ratio of CLSM using multiple regression analysis to design the CLSM. The flow values and strength at 12 hrs and 7days were measured in accordance with the mixing ratio of CLSM which consists of 7 different materials, such as CSA expansive agent, ordinary Portland cement, fly ash, sand, silt, water, and accelerator. The multiple regression was performed with the proportions of each material of CLSM as independent variables and the measured properties as dependent variables using SPSS Statistics 23 which is a statistical analysis program. The regression coefficients were estimated from the first to third order equation models for the materials. From the results, the third order model for the flow values and the first order models for 12hrs and 7days strength are the most appropriate models. This study suggests that the mixing ratio required for constructions may be effectively estimated from the regression models about the characteristics of CLSM, before performing experimental tests.

• Journal of the Korea Concrete Institute
• /
• v.23 no.1
• /
• pp.87-98
• /
• 2011

Crack formations are inevitable in reinforced concrete structures. To estimate crack widths, empirical formulae are used widely and indirect crack controling methods of limiting bar spacing and bar diameter are also used due to their simplicity. In EC2, the characteristic crack width is calculated by multiplying maximum crack spacing and average strain. In this study, limit values of maximum bar spacing and bar diameter are examined as the material characteristics are varied. Two models of tension stiffening effect and maximum crack spacing and their effects are evaluated. The obtained results are compared with the values obtained using KCI method. The results showed that a significant difference is found when two tension stiffening effect are employed, and an under-estimation is found when 2nd order tension stiffening effect and maximum crack spacing limit from Part II were implemented. Therefore, a rational indirect crack control method attained using the tension stiffening effect of 2nd order form is needed. Also, a consistency in serviceabiliy analysis in flexural members needs to be secured. In order to achieve these goals, two crack controling models are suggested.

• Journal of Animal Science and Technology
• /
• v.47 no.5
• /
• pp.703-710
• /
• 2005

Data from Hanwoo steers and bull calves were analyzed to see the phenotypic and genetic relationships between carcass traits from four different covariance models. Four models fit test station and test period as fixed effect of contemporary group and sire as random effect assuming paternal half-sib relationships among animals. Each model fits one of linear covariate (s) of different slaughter end points-age at slaughter in the first order, age at slaughter in the first and second order, slaughter weight or back fat thickness at 12-13th rib of cold carcass. Age at slaughter in its second order was not significant. Age at slaughter accounted for signifi- cant amount of genetic variances and covariances of carcass traits. Heritability estimates of back fat thickness, rib eye area, carcass weight, marbling score and dressing percentage were 0.34, 0.22, 0.24, 0.42 and 0.18, respectively at constant age basis. The genetic correlation between carcass weight and the other variables were all positive and low to high in magnitude. Genetic correlations between back fat thickness and rib eye area and between marbling score and dressing percentage were low but negative. Variance and covariance structure between these traits were shifted to a great extent when these variables were regressed on slaughter weight or on back fat thickness. These two covariates counteracted to each other but they adjusted each carcass variable or their interrelationship according to differential growth of body components, bone, muscle and fat. Slaughter weight tended to decrease genetic variances and covariances of carcass weight and between component traits and back fat thickness tended to increase those of rib eye area and between rib eye area and carcass weight.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.9 no.2
• /
• pp.83-90
• /
• 1989

A runoff model was estabilished for the direct runoff hydrograph at each subareas by obtaining the storage coefficient based on stream magnitudes of geomorphic parameters. For this, the relationship between flowsection and channel distance from the outlet of each subareas was assumed as nonlinear equation, and compared with linear one. The applicability of the runoff model to the real watershed was tested for the Bochung river basin. The results of the analysis show that the model was approved to be used for the prediction of small watershed having no runoff records and a linear equation between flowsection and channel distance from the outlet of each subareas was more similar to the observed data for the upper subarea with a steep slope and small area, on the other hand, nonlinear equation for the lower subarea with mild slope and relatively large area.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.9
• /
• pp.505-512
• /
• 2017

The adsorption characteristics of Sr ion in aqueous solution was examined using zeolite NaA powder (Z-PA) and pellets (Z-BA). In batch experiment, the adsorption of Sr ions by Z-BA and Z-PA was well expressed by pseudo-second-order kinetic model than psedo-first-order kinetic model. Experimental isotherm results was well fitted to Langmuir isotherm model and the maximum adsorption capacities obtained from Langmuir isotherm model were 233.32 mg/g for Z-PA and 164.60 mg/g for Z-BA, respectively. The continuous experiment results showed that the total Sr ion uptake (q) increased, but the breakthrough time, effluent volume ($V_{eff}$) and total removal (R) of Sr ion decreased with the Sr ion concentration. The breakthrough curves obtained from the experiment was modeled by Thomas model.

• Proceedings of the KIEE Conference
• /
• 2008.10b
• /
• pp.251-252
• /
• 2008

Type-2 퍼지 집합은 Type-1 퍼지 집합에서는 다루기 어려운 언어적인 불확실성을 더욱 효과적으로 다룰 수 있다. TSK 퍼지 로직 시스템(TSK Fuzzy Logic Systems; TSK FLS)은 후반부를 1차 및 2차 함수식으로 나타내며 Mamdani 모델과 함께 가장 널리 사용되는 모델이다. 본 연구의 Interval Type-2 TSK FLS은 전반부에서 Type-2 퍼지 집합을 이용하고 후반부는 계수가 Type-1 퍼지집합인 1차식을 사용한다. 또한 전반부는 가우시안 형태의 Type-2 멤버쉽 함수를 사용하며, 오류역전파 학습알고리즘을 사용하여 파라미터들을 최적화 한다. 또한 학습에 앞서 PSO(Particle Swarm Optimization) 알고리즘을 사용하여 최적 학습률을 찾아 모델의 학습능력을 보다 효율적으로 한다. 본 논문에서는 Type-1과 Type-2 FLS의 성능을 가스로 공정 데이터를 적용하여 두 모델의 성능을 비교하고 노이즈를 추가한 데이터를 이용하여 노이즈에 대한 성능도 비교 분석한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2008.04a
• /
• pp.321-324
• /
• 2008

Type-2 퍼지 집합은 Type-1 퍼지 집합에서는 다루기 어려운 언어적인 불확실성을 더욱 효과적으로 다룰 수 있다. TSK 퍼지 로직 시스템(TSK Fuzzy Logic Systems; TSK FLS)은 Mamdani 모델과 함께 가장 널리 사용되는 FLS이다. 본 연구의 Interval Type-2 TSK FLS 모델은 전반부에서 Type-2 퍼지 집합을 이용하고 후반부는 계수가 상수인 1차식을 사용한다. 전반부의 파라미터는 오류역전파 방법(Back-propagation)을 통한 학습으로 결정되고, 후반부 파라미터(계수)들은 Least squre method(LSM)를 사용하여 결정된 값을 사용하여 모델을 구축한다. 본 논문에서는 Type-1 TSK FLS과 Type-2 TSK FLS의 성능을 가스로 공정 데이터를 적용하여 비교 분석한다. 또한 랜덤 화이트 가우시안 노이즈를 추가한 테스트 데이터를 사용하여 노이즈에 대한 성능을 분석한다.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1992.05a
• /
• pp.61-61
• /
• 1992

여러 점막 추출액증 Met-Enk의 효소적 분해는 매우 신속하였고 1차식에 따랐으며 점막측 추출액에서의 분해속도는 직장>눈>질>비강점막의 순이었다. 비강, 직장, 질점막의 점막측 및 장막측 추출액 간의 분해속도에는 유의성 있는 차이는 없었으나 눈점막의 경우 내피측 추출액에서의 분해속도 (1.03 $\times$ $10^{-3}$ $min^{-1}$)가 표피측 추출액에서보다 현저히 낮았다. 모든 추출액에서 검출된 주요 분해산물은 Tyr 및 Des-Tyr-Met-Enk로 천연 Met-Enk의 점막 추출액중 분해는 주로 aminopeptidase류가 관여되고 있음을 알았으며 Tyr-Gly, Tyr-Gly-Gly등의 분해산물이 소량 출현함으로 보아 endopeptidase류도 분해에 다소 관여하고 있음을 알았다. YAGFM은 Met-Enk보다 분해가 현저히 지연되었으며 그 분해속도도 직장>질>비점막의 순이었다. 이러한 분해는 분해산물로 Tyr이 검출되지 않은점으로 보아 YAGFM의 점막 추출액중 분해는 주로 endopeptidase류가 주로 관여되는 것으로 추정된다.