• Environmental Engineering Research
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• v.21 no.4
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• pp.393-400
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• 2016

The aim of this study was to evaluate the biomass production and dairy wastewater treatment using Chlorella vulgaris. The results indicated that the maximum percentages of biochemical oxygen demand, chemical oxygen demand, suspended solids, total nitrogen, and total phosphorus removed were 85.61%, 80.62%, 29.10%, 85.47%, and 65.96%, respectively, in dairy effluent at 10 d. A maximum of 1.23 g/L dry biomass was obtained in 7 d. The biomass productivity was strongly influenced by the nutrient reduction in the dairy effluent. The biodiesel produced by the C. vulgaris in the dairy effluent was in good agreement with the American Society of Testing and Materials-D6751 and European Standards 14214 standards. Therefore, using dairy effluent for microalgal cultures could be a useful and practical strategy for an advanced, environmentally friendly treatment process.

• Environmental Engineering Research
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• v.22 no.4
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• pp.356-362
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• 2017

This study investigates the use of methyl-esterified eggshell membranes (MESM) for the harvesting of microalgae species under various conditions. Eggshell membranes were esterified with HCl to impact polycationic characteristics. After methyl esterification, the negative surface charge property of eggshell membrane was changed from negative to positive for all pH values to improve microalgae sorption capacity. The harvesting efficiency of microalgae by MESM reached 78-99% for all pH ranges evaluated. In addition, a 150 mesh particle size and $10mg\;L^{-1}$ MESM dose were found to yield up to 98% microalgae harvesting. These results indicate that the high cationic charge of MESM strongly adsorbs the negatively-charged microalgae. MESM is biocompatible and can be applied to the harvest of microalgae.

• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.110-116
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• 2008

A RFID is an automatic data collection system based on the radio frequency and is the key technology of ubiquitous computing environments. Since the locations of objects attached by RFID tags can be acquired by readers, it is possible to query the locations of tags. To query tags efficiently, the data of RFID tags should be modeled and indexed. However, since the location information of tags, the predicates of queries, are differ from coordinates of moving objects, it is difficult to model tags under the concept of moving objects, In this paper, we propose the location model of tags to represents the trajectories of tags. The location model is composed of the set and graph based approaches.

• Journal of information and communication convergence engineering
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• v.4 no.1
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• pp.36-40
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• 2006

A new method of digital image analysis technique for medical images of cancer cell is presented. This paper deals with the cancer cell discrimination. The object images were the Thyroid Gland cell images that were diagnosed as normal and abnormal. This paper proposes a new discrimination method based on fuzzy logic algorithm. The focus of this paper is an automatic discrimination of cells into normal and abnormal of medical images by dominant feature parameters method with fuzzy algorithm. As a consequence of using fuzzy logic algorithm, the nucleus were successfully diagnosed as normal and abnormal. As for the experimental result, average recognition rate of 64.66% was obtained by applying single parameter of 16 feature parameters at a time. The discrimination rate of 93.08% was obtained by proposed method.

• Journal of information and communication convergence engineering
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• v.2 no.2
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• pp.61-66
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• 2004

This paper presents a way to maximize transmission efficiency and reception ability through transmission diversity technology, which can be adapted to wireless multimedia Wireless LAN system. The presented method is a comparative analysis between a case where parameter a for time average is 0.3.1 with consideration of channel presumption with two types of rms delayed spread, which is 50nsec. 150nsec, for the performance analysis of STTC (Space-Time Trellis Code) adopting time-space ciphering method appropriate for MIMO channel, and performance in the case where presumed channel value from long training column section is applied to according frame in a single frame. The result showed that BER brought SNR improvement of l.0dB in $10^{-3}$ when a was 0.3 than adopting only the long training column, and showed increase of general performance improvement for the sake of time average rather than the case without.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.225-232
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• 2021

Obesity is caused by the accumulation of triglycerides in adipocytes by the differentiation and lipid synthesis process of pre-adipocytes, and excessive accumulation of adipocytes by the activated Adipogenesis process within the differentiated cells. Therefore, inhibiting the differentiation of adipocyte cells or controlling the adipogenesis process is known as an effective treatment method for obesity. This study evaluates the inhibition of Red beet root extract on pancreatic lipase and pre-adipocyte cell differentiation. Also it evaluates the Red beet root extract activities on C/EBP-𝛼,𝛽, and PPAR-𝛄. The experiments proved that the Red beet root extract inhibits pancreatic lipase by concentration dependency. Further, in 3T3-L1 inhabitation experiment, it was found Red beet root extract inhibited adipocyte formation. Red beet root extract also inhibits the expression of C/EBP-𝛼, C/EBP-𝛽, and PPAR-𝛾 which effect the process of adipocytic differentiation. We therefore concluded that RBE has a high potential to further studies on anti-obesity effect.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.23 no.3
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• pp.211-236
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• 2019

This paper is devoted to the study and investigation of the Runge-Kutta discontinuous Galerkin method for a system of differential equations consisting of two hyperbolic conservation laws. The numerical coupling flux which is used at a given interface (x = 0) is the upwind flux. Moreover, in the linear case, we derive optimal convergence rates in the $L_2$-norm, showing an error estimate of order ${\mathcal{O}}(h^{k+1})$ in domains where the exact solution is smooth; here h is the mesh width and k is the degree of the (orthogonal Legendre) polynomial functions spanning the finite element subspace. The underlying temporal discretization scheme in time is the third-order total variation diminishing Runge-Kutta scheme. We justify the advantages of the Runge-Kutta discontinuous Galerkin method in a series of numerical examples.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.33-38
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• 2022

This study investigates the outlet temperature of coolant heater based on heat and flow volume conditions. Through computer simulation, the coolant temperature at the outlet was analyzed to investigate the heat and flow volume conditions of the coolant heater, and the optimal conditions were derived. Results show that heat and flow volume conditions, it was confirmed that heat condition is 0.424 W/mm³, and flow volume condition is 500 l/h, demonstrates optimal conditions. The results of this study can be utilized to efficiently control the coolant temperature through various heat and flow volume conditions.

• Journal of Preventive Medicine and Public Health
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• v.50 no.1
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• pp.38-59
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• 2017

Objectives: Few attempts have been made to develop a generic health-related quality of life (HRQoL) instrument and to examine its validity and reliability in Korea. We aimed to do this in our present study. Methods: After a literature review of existing generic HRQoL instruments, a focus group discussion, in-depth interviews, and expert consultations, we selected 30 tentative items for a new HRQoL measure. These items were evaluated by assessing their ceiling effects, difficulty, and redundancy in the first survey. To validate the HRQoL instrument that was developed, known-groups validity and convergent/discriminant validity were evaluated and its test-retest reliability was examined in the second survey. Results: Of the 30 items originally assessed for the HRQoL instrument, four were excluded due to high ceiling effects and six were removed due to redundancy. We ultimately developed a HRQoL instrument with a reduced number of 20 items, known as the Health-related Quality of Life Instrument with 20 items (HINT-20), incorporating physical, mental, social, and positive health dimensions. The results of the HINT-20 for known-groups validity were poorer in women, the elderly, and those with a low income. For convergent/discriminant validity, the correlation coefficients of items (except vitality) in the physical health dimension with the physical component summary of the Short Form 36 version 2 (SF-36v2) were generally higher than the correlations of those items with the mental component summary of the SF-36v2, and vice versa. Regarding test-retest reliability, the intraclass correlation coefficient of the total HINT-20 score was 0.813 (p<0.001). Conclusions: A novel generic HRQoL instrument, the HINT-20, was developed for the Korean general population and showed acceptable validity and reliability.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.18-24
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• 2016

Mineral carbonation is a technology for permanently storing carbon dioxide by reacting with metal oxides containing calcium and magnesium. In this study, we used sea water and alkaline industrial by-product such as paper sludge ash (PSA) for the storage of carbon dioxide through direct carbonation. We found the optimum conditions of both sea water content (mixing ratio of sea water and PSA) and reaction time required in the direct carbonation through various experiments using sea water and PSA. In addition, we compared the amounts of carbon dioxide storage with the cases when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA. The amount of carbon dioxide storage was calculated by using both solid weight increase through the carbonation reaction and the contents of carbonate salts from thermal gravimetric analysis. PSA particle used in this study contained 67.2% of calcium. The optimum sea water content and reaction time in the carbonation reaction using sea water and PSA were 5 mL/g and 2 hours, respectively, under the conditions of 0.05 L/min flow rate of carbon dioxide injected at $25^{\circ}C$ and 1 atm. The amounts of carbon dioxide stored when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA were 113 and $101kg\;CO_2/(ton\;PSA)$, respectively. The solid obtained through the carbonation reaction using sea water and PSA was composed of mainly calcium carbonate in the form of calcite and a small amount of magnesium carbonate. The solid obtained by using ultra-pure water, also, was found to be carbonate salt in the form of calcite.