• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.225-231
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• 2002

Severe cracks on Reinforced Concrete (RC) structures caused by structural displacement can be often one of the main reasons for the degradation of tensile and flexural rigidities of RC structures and for the deterioration of durability and serviceability of RC structures through accelerated steel corrosion. These combined factors adversely affect the performance of RC concrete, leading to shortened life time of RC structures. In consideration of these problems, we conducted 3 point bending experiments by employing three different types of concrete specimens: fiber-net reinforced concrete (FNRC), polypropylene-fiber reinforced concrete (PFRC), and plain concrete (PC). FNRC is well known for its strong corrosion resistance, light self-weight, and excellent tensile strength, while PFRC is known to be effective in crack control. FNRC was found to have the best first and final crack resistances followed by PFRC and PC, as evidenced by the highest initial crack load and the smallest final crack width, respectively. The FNRC specimens with various tensile strength of fiber net exhibited greater ultimate strengths than those for PFRC and PC. Furthermore, the crack widths of FNRC specimens were smaller than those calculated by the crack-width estimation equation of the KCI and ACI code. Therefore, we conclude that fiber net reinforcement is effective not only on crack control, but also on loading share.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.25-31
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• 2002

This study was carried out to estimate aboveground biomass and net primary production in an average 37-year-old Quercus acutissima stand of Pohang area. Ten sample trees were cut in the forest and soil samples were collected in August, 2001. Estimation for aboveground biomass and net primary production was made by the equation model Wt=$aD^b$ where Wt is ovendry weight in kg and D is DBH in cm. Total aboveground biomass was 115.47ton/ha in the study forest. The proportion of each tree component to total aboveground biomass was high in order of bolewood(63.9%), branches(19.8%), bolebark(16.2%) and leaves(1.2%) in the study forest. Aboveground total net primary production was estimated at 7.89ton/ha in the study area. The proportion of each tree component to total net primary production was high in order of bolewood, bolebark, branch, and leaves.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.12
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• pp.1901-1908
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• 2007

The aim of this series of experiments was to examine the opportunity for application of X-ray computer tomography (CT) in cattle production. Firstly, tissue composition of M. longissimus dorsi (LD) cuts between the $11-13^{th}$ ribs (in Exp 1. between the $9-11^{th}$ ribs), was determined by CT and correlated with tissue composition of intact half carcasses prior to dissection and tissue separation. Altogether, 207 animals of different breeds and genders were used in the study. In Exp. 2 and 3, samples were taken from LD cuts, dissected and chemical composition of muscle homogenates was analysed by conventional procedures. Correlation coefficients were calculated among slaughter records, tissues in whole carcasses and tissue composition of rib samples. Results indicated that tissue composition of rib samples determined by CT closely correlated with tissue composition results by dissection of whole carcasses. The findings revealed that figures obtained by CT correlate well with the dissection results of entire carcasses (meat, bone, fat). Close three-way coefficients of correlation (r = 0.80-0.97) were calculated among rib eye area, volume of cut, pixel-sum of adipose tissue determined by CT and intramuscular fat or adipose tissue in entire carcasses. Estimation of tissue composition of carcasses using equations including only CT-data as independent variables proved to be less reliable in prediction of lean meat and bone in carcass ($R^2 = 0.51-0.86$) than for fat (($R^2 = 0.83-0.89$). However, when cold half carcass weight was also included in the equation, the coefficient of determination exceeded $R^2 = 0.90$. In Exp. 3 tissue composition of rib samples by CT were compared to the results of EUROP carcass classification. Findings revealed that CT analysis has higher predictive value in estimation of actual tissue composition of cattle carcasses than EUROP carcass classification.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.222-233
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• 2000

A methodology for determining age by otolith of small yellow croaker, Pseudosoiaena polyactis Bleeker, was developed. A thin section method was chosen to be suitable for age determination because the otolith had a three-dimensional shape and thus it was not possible to read the otolith rings on the surface. The clear rings were identified on the vertical-axis cross-sectioned otoliths. The total length-total weight relationship and the growth parameters were estimated with error structure to endow with accuracy. In the relationship between total length and total weight, a multiplicative error structure was assumed because variability in growth increased as a function of the length, and the estimated equation was $W=0.0049L^{3.2153}$. The variability in growth was constant as a function of the age, revealing an additive error structure. The von Bertalanffy growth parameters were obtained from a nonlinear regression as $L_{\infty}= 37.11cm, K=0.20/yr and t_0=-1.88.$

• Kidney Research and Clinical Practice
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• v.37 no.4
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• pp.338-346
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• 2018

Background: The most common cause of acute kidney injury (AKI) in pregnancy is preeclampsia. Serum cystatin C (CysC) is a potential biomarker of early kidney damage as its levels are not disturbed by volume status changes in pregnancy, and serum CysC levels could serve as a replacement for conventionally used creatinine. In this study, we investigated the serum levels of CysC in severe preeclampsia cases and the associations between CysC levels and poor obstetric outcomes. Methods: Our cohort included severe preeclampsia patients with a normal serum creatinine level. Creatinine was measured to calculate estimated glomerular filtration rate (eGFR) based on the Cockcroft and Gault, Modification of Diet in Renal Disease Study (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, while CysC was measured to calculated eGFR based on a CysC-based equation. We then evaluated the correlations between serum CysC level, eGFR, and obstetric outcomes. Results: Twenty-six patients were evaluated of which 38.5% delivered preterm and 30.8% had low-birth weight babies. Unlike creatinine-based eGFR and CysC-based eGFR, serum CysC demonstrate significant negative correlation with gestational age. Receiver operating characteristic curve analysis indicated that serum CysC is a potential biomarker of preterm delivery with a cut-off serum level of 1.48 mg/L with 80% sensitivity and 75% specificity. Conclusion: GFR estimation using CysC is likely to be inaccurate in pregnancy. However, we found a significant correlation between preterm delivery and serum CysC level. Our results suggest that serum CysC level has the potential to predict preterm delivery in severe preeclampsia patients.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.25-36
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• 2001

The purpose of this paper is to discuss the effects of soil properties such as liquid limit, water content, etc. on the compression index and to propose the empirical equation of compression index far regional clay and to verify the application Back Propagation Neural Network(BPNN). The compression index values obtained from laboratory tests are in the range of 0.01 to 3.06 for clay soils sampled in eleven regions. As the compare with the results of laboratory test and the predicted compression index value from the proposed empirical equations, the results of empirical equations including single soil parameter have a possibility to be overestimated. Also, the results of empirical equations including multiple soil parameters closed to the measured value more than that of empirical equations including single soil parameter, but the standard error for measured value obtained larger than 0.05. For these reasons, the empirical equations including single or multiple soil parameters proposed base on the results of laboratory test and the determination coefficient is up to 0.89. The result of BPNN shows that correlation coefficient and standard error between test and neural network result is larger than 0.925 and smaller than 0.0196, which means high correlativity, respectively. Especially, the estimated result by neural network, using only three parameters such as natural water content, dry unit weight and in-situ void ratio among various factors is available to the estimation of compression index and the correlation coefficient is 0.974. This result verified the possibility that if BPNN use, the compression index can be predicted by the parameters, which obtained from simplex field test.

• Journal of Korean Society of Forest Science
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• v.94 no.3 s.160
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• pp.161-167
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• 2005

Above and belowground biomass for Phyllostachys pubescens was determined in Jinju, Gyeongsangnam-do. Regression analyses of dry weights of culms, foliages, and twigs versus diameter at breast height were used to calculate regression equations of the form of log Y = a + blogX. Total aboveground biomass for Phyllostachys pubescens was 69.7 ton/ha and rhizomes and roots biomass were 13.7 ton/ha and 7.5 ton/ha, respectively. Culms account for about 60% of total aboveground biomass. The aboveground biomass of each component was decreased in the order of culms>foliages>twigs. As diameter at breast height grew thicker, the proportion of culms to total aboveground biomass increased. The proportion of dry weight of culms to green weight gradually increased with height in a bamboo tree and ages. Nutrients (kg/ha) of litter layer were distributed as follows: N(45.1), Ca(17.3), K(6.1), Mg(3.6), P(3.5) and Na(0.7). Nitrogen and K were given much weight in total nutrients of rhizomes and roots. These results will be useful in measuring carbon stock and drawing up management plan to increase it for Phyllostachys pubescens stand.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.75-86
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• 2020

The purpose of this study is to develop a technology for estimating rice growth and damage effect according to bacterial leaf blight using UAV multi-spectral imagery. For this purpose, we analyzed the change of aerial images, rice growth factors (plant height, dry weight, LAI) and disease effects according to disease occurrence by using UAV images for 3 rice varieties (Milyang23, Sindongjin-byeo, Saenuri-byeo) from 2017 to 2018. The correlation between vegetation index and rice growth factor during vegetative growth period showed a high value of 0.9 or higher each year. As a result of applying the growth estimation model built in 2017 to 2018, the plant height of Milyang23 showed good error withing 10%. However, it is considered that studies to improve the accuracy of other items are needed. Fixed wing unmanned aerial photographs were also possible to estimate the damage area after 2 to 4 weeks from inoculation. Although sensing data in the multi-spectral (Blue, Green, Red, NIR) band have limitations in early diagnosis of rice disease, for rice varieties such as Milyang23 and Sindongjin-byeo, it was possible to construct the equation of infected leaf area ratio and rice yield estimation using UAV imagery in early and mid-September with high correlation coefficient of 0.8 to 0.9. The results of this study are expected to be useful for farming and policy support related to estimating rice growth, rice plant disease and yield change based on UAV images.

• Korean Journal of Poultry Science
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• v.11 no.2
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• pp.127-132
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• 1984

In order to investigate the effect of temperature variation in winter season on the egg production and energy utilization of poultry, 30week-old Warren layers were reared during 17 weeks of experimental period, from Nov. 1st, 1980 to Feb. 27th. 1981. The effect of temperature change on the body weight, feed intake and feed conversion was not found. But the outdoor average and the indoor minimum temperature had changed Positively 0.46 and 0.24% of henday egg production per 1$^{\circ}C$ fluctuation, respectively. Daily metabolizable energy utilized during 32 (Nov.15th), 34(Dec.1st) and 46(Feb. 27th) week-old reached to, respectively, 358, 385 and 419 kcal per bird, and 159, 173 and 176 kcal per kg body weight. Also the metabolizable energy utilization correlated negatively with the ambient temperature fluctuation, while the equation by NRC(1981) for metabolizable energy requirement estimation were well in accord with these results when the indoor minimum temperatures were based. And the metabolizable energy requirements per kg body weight were 1.7, 1.6 and 2.1 kcal, respectively, according as 1C fluctuation of outdoor, indoor maximum and indoor maximum and indoor minimum temperatures. Thus it is appeared that indoor temperatures fluctuated by outdoor temperatures will affect the egg Production and metabolizable energy utilization of hen in winter season of Korea.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.541-548
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• 2012

The hollow slab has advantages that its self-weight does not greatly increase notwithstanding the increase of its thickness and its flexural performance does not significantly degrade in comparison with general reinforced concrete slab. However, the utilization of the hollow slab is currently being underestimated in spite of structural system that enables economic design of building and construction of eco-friendly structure. the significant reasons for this situation is that the method of structural analysis and design for hollow slab is not generalized. In this study, to consider practical compressive zone of hollow slab, the equation for its flexural strength is proposed by the volume of compressive stress block according to neutral axis location in hollow section assumed. Existing estimation method of flexural strength of hollow slab considering only compressive zone above hollow part is evaluated as the most conservative method and the method estimating flexural strength by two alternative cross-section of hollow slab is evaluated as more practical method.