• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.273-279
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• 2007

Probabilistic Risk Assessment considering statistically random variables is performed for the preliminary design of an Arch Bridge. Component reliabilities of girders have been evaluated using the response surfaces of the design variables at the selected critical sections based on the maximum shear and negative moment locations. Response Surface Method (RSM) is successfully applied for reliability analyses lot this relatively small probability of failure of the complex structure, which is hard to be calculated by Monte-Carlo Simulations or by First Order Second Moment method that can not easily calculate the derivative terms in implicit limit state functions. For the analysis of system reliability, parallel resistance system composed of girders is modeled as a parallel series connection system. The upper and lower probabilities of failure for the structural system have been evaluated and compared with the suggested prediction method for the combination of failure modes. The suggested prediction method for the combination of failure modes reveals the unexpected combinations of element failures in significantly reduced time and efforts, compared with the previous permutation method or conventional system reliability analysis method.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.6-12
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• 1988

To improve the individual packaging method and extend the shelf life of mackerel (Scomber japonicus), salted and unsalted mackerel fillets were packaged in laminated plastic film bag (Nylon/PE: $20{\mu}m/40{\mu}m,\;12{\times}15$ cm) filled with $CO_2$ gas, in vacuum, and stored at O and/or $5^{\circ}C$. The other samples were packaged in plastic foam trays, overwrapped with oxygen permeable film (control), and stored at same temperature. Volatile basic nitrogen (VBN), trimethylamine (TMA), histamine (HM) and viable cell counts (VCC) were progressed with the increasing of storage time, but thiobarbituric acid (TBA) values decreased gradually after reaching at a maximum peak in 5-9 days. Judging from 4 chemical components, VBN was the most available component in quality judgement of mackerel fillets and its upper limiting content was 25 mg%. Regression equation for shelf life prediction of mackerel fillets with sensory evaluation and VBN component was determined.

• Journal of fish pathology
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• v.19 no.3
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• pp.253-265
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• 2006

The purpose of this study was to obtain reference data of parameters for hematological health diagnosis in marine fish and also evaluate application of veterinary chemistry analyzer used to those blood tests. A blood profile of total 522 fish for black rockfish (Sebastes schlegeli), red seabream (Pagrus major), rock bream (Oplegnathus fasciatu) and black seabream (Acanthopagrus schlegeli) cultured in mari-floating netcage of Gyeongnam province was determined by hematocrit (Ht), hemoglobin (Hb) and blood chemistry tests (total protein, albumin, alkaline phosphatase, blood urea nitrogen, lactate dehydrogenase, triglyceride, total cholesterol, creatinine, aspartate aminotransferase, alanine aminotransferase, glucose). Ht was measured by microhematocrit method. Hb and plasma chemistry were analysed by establishing baseline ranges for a dry chemical system of FUJI DRI-CHEM 3000. Actually recorded values of Hb and plasma chemistry by the analyzer were notably outside from the minimum and/or maximum of the established reference value. Albumin and alanine aminotransferase were not detectable in the range of 68～66%. Lactate dehydrogenase, total protein, alkaline phosphatase and glucose were not detectable in the range of 42～21%. Total cholesterol, aspartate aminotransferase, triglyceride, hemoglobin and creatinine were not detectable in the range of 18～3%. However, the values of blood urea nitrogen were below the detectable limits of the analyzer.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.171-187
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• 2017

Thisstudy presentsthe method for deriving surface visibility from satellite retrieved AOD. To do thisthe height of aerosol distribution isrequired. This distribution would be in thisstudy represented by the two heights; if there is a discrete atmospheric layer, which is physically separated from the above layer, the upper height of the layer is assumed as Aerosol Layer Height(ALH). In this case there is clear minimum in the Relative Humanity vertical distribution. Otherwise PBLH(Planetary Boundary Layer Height) is used. These heights are obtained from the forecast data of Regional Data Assimilation and Prediction System(RDAPS). The surface visibility is estimated from MODIS AOD and ALH/PBLH, using Koschmieder's Law for ALH and the empirical relations for PBLH. The estimated visibility are evaluated from the visibility measurements of 9 eve-measurement stations and 17 PWD22 stations for the spring of 2015 and 2016. Verification of the estimated visibility shows that there are considerable differencesin statistical verification value depending on stations, years, morning(Terra)/afternoon(Aqua). The better results are shown in the midwest part of korean peninsula for Terra of 2016. The results are summarized as; correlation coefficients of higher than 0.65, for low visibility RMSE of 3.62 km and ME of 2.29 km or less, POD of higher than 0.65 and FAR of 0.5 or less. Verification results were better with increase in the number of low-visibility data.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.415-421
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• 2008

Reinforced concrete starts to corrode when the chloride ion concentration which is the sum of included in concrete and penetrated from environments exceeds a certain level of critical chloride concentration. Therefore each country regulates the upper bounds of chloride amount in concrete and the regulations are different for each country due to its circumstances. In this study, the critical threshold chloride content according to unit cement amount is empirically calculated to propose a reasonable regulation method on the chloride amount. As a result, the critical threshold chloride content increases considerably according to cement content and it agrees with the established theories. The present regulations on total chloride amount 0.3 or 0.6 kg chloride ions per $1\;m^3$ of concrete does not reflect the influences of mix design, environmental conditions and etc. So it can be said that it is more reasonable to regulate the critical threshold chloride content by the ratio of chloride amount per unit cement content than by the total chloride content in $1\;m^3$ of concrete.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.5
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• pp.47-56
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• 2008

This study was performed to evaluate the effect of Response modification factors (R-factor) in 3-, 9- and 20- story steel Moment Resisting Frame (MRF) buildings. Each structure was designed using a R-factor of 8, as tabulated in the 2000 International Building Code provision (IBC 2000) and Korea Building Code (KBC) 2008. In order to evaluate the maximum and minimum performance expected for such structures, an upper bound and lower bound design were adopted for each model. Next, each analytical model was designed using different R-factors (8, 9, 10, 11, 12) and four different structural periods with the original fundamental period. For a detailed case study, a total of 150 analytical models were subjected to 20 ground motions representing a hazard level with a 2% probability of being exceeded in 50 years. In order to evaluate the performance of the structures, static push-over and non-linear time history analysis (NTHA) were performed, and displacement ductility demand was investigated to consider the ductility capacity of the structures. The results show that the dynamic behaviors for the 3- and 9-story buildings are relatively stable and conservative, while the 20-story buildings show a large displacement ductility demand due to dynamic instability factors. (e.g. P-delta effect and high mode effect)

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.171-182
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• 2007

In this study, as a method for decreasing the confidence interval of the estimates of Clark hydrograph's concentration time and storage coefficient, regression equations of these parameters with respect to those of rainfall, meteorology, and basin characteristics are derived and analyzed using the Monte Carlo simulation technique. The results are also reviewed by comparing them with those derived by applying the Bootstrap technique and empirical equations. Results derived from this research are summarized as follows. (1) Even in case of limited rainfall events are available, it is possible to estimate the mean runoff characteristics by considering the affecting factors to runoff characteristics. (2) It is also possible to use the Monte Carlo simulation technique for estimating and evaluating the confidence intervals for concentration time and storage coefficient. The confidence intervals estimated in this study were found much narrower than those of Yoo et al. (2006). (3) A supporting result could also be derived using the Bootstrap technique. However, at least 20 independent rainfall events are necessary to get a rather significant result for concentration time and storage coefficient. (4) No empirical equations are found to be properly applicable for the study basin. However, empirical equations like the Kraven(I) and Kraven(II) are found valid for the estimation of concentration time, on the other hand the Linsley is found valid for the storage coefficient In this study basin. But users of these empirical formula should be careful as these also provide a wide range of possible values.

• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.133-143
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• 2012

To evaluate the kinetic energy of the raindrops, the drop size distribution and the terminal velocity of the raindrops had been measured from January to September 2010 using the laser-optical disdrometer in KIGAM, Daejeon, Korea. The relationship between kinetic energy (KE) and rainfall intensity (I) was computed as logarithmic and exponential model, respectively, under the rainfall intensity of about 142mm/h. The exponential model is more suitable for the relationship of KE-I than the logarithmic model, because the exponential model presented better fit for KE over 50mm/h of rainfall intensity. Meanwhile, the differences of the total kinetic energy existed in rainfall events with almost same total rainfall depth, and KE values of Daejeon at high rainfall intensity underestimated rather than the others under temperate climate. Therefore, these differences of KE in rainfall events and geographical regions imply the result from the variations of rainfall intensity within a rainfall event.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.263-268
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• 2021

The purpose of this study was to propose a model which is suitable for the actual delivery system by designing a fetal delivery hospital operation management and fetal health classification model. The number of deaths during childbirth is similar to the number of maternal mortality rate of 295,000 as of 2017. Among those numbers, 94% of deaths are preventable in most cases. Therefore, in this paper, we proposed a model that predicts the health condition of the fetus using data like heart rate of fetuses, fetal movements, uterine contractions, etc. that are extracted from the Cardiotocograms(CTG) test using a random forest. If the redundancy of the data is unbalanced, This proposed model guarantees a stable management of the fetal delivery health management system. To secure the accuracy of the fetal delivery health management system, we remove the outlier which embedded in the system, by setting thresholds for the upper and lower standard deviations. In addition, as the proportion of the sequence class uses the health status of fetus, a small number of classes were replicated by data-resampling to balance the classes. We had the 4~5% improvement and as the result we reached the accuracy of 97.75%. It is expected that the developed model will contribute to prevent death and effective fetal health management, also disease prevention by predicting and managing the fetus'deaths and diseases accurately in advance.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.3
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• pp.119-123
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• 2013

Simplified control logic was devised to fabricate and operate the modified atmosphere (MA) container of fresh produce equipped with gas-diffusion tube whose opening/closing was controlled in response to real time $O_2$ concentration. This is a simplified ramification of the previously developed control logic using both $O_2$ and $CO_2$ concentrations ([$O_2$] & [$CO_2$]). The developed logic was applied to and tested by a container system filled with spinach at $10^{\circ}C$ having optimum MA window of [$O_2$] of 7~10% and [$CO_2$] of 5~10%. It was shown that setting the proper on-off limit (11%) for $O_2$ control based on the assumed relationship $[O_2]+[CO_2]$=21% could attain the desired $CO_2$ concentration just below the upper tolerance limit ($[CO_2]_H$, 10%). The $O_2$ control point can be the lower tolerance limit or adjusted one (21-$[CO_2]_H$) depending on the commodity's MA requirement. The developed logic using single $O_2$ sensor could attain the equilibrated [$O_2$] of 11% with [$CO_2$] of 8~9% which was desired and similar to that of its predecessor ([$O_2$] of 9~10% with [$CO_2$] of 10%) using both $O_2$ and $CO_2$ sensors. Both MA containers (one only with single $O_2$ sensor control and one with $O_2$ and $CO_2$ sensors) could also keep the spinach quality without significant difference between them, but significantly better than perforated control package of air.