• Environmental Engineering Research
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• 제21권4호
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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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• 제22권4호
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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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• 제6권1호
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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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• 제4권1호
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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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• 제2권2호
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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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• 제10권4호
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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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• 제23권3호
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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.

• 반도체디스플레이기술학회지
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• 제21권1호
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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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• 제50권1호
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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.

• 한국해양환경ㆍ에너지학회지
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• 제19권1호
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• pp.18-24
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• 2016

광물탄산화는 이산화탄소를 칼슘, 마그네슘 등을 함유한 금속산화물과 반응시켜 영구적으로 저장하는 기술이다. 본 연구에서는 직접탄산화 방법으로 이산화탄소를 저장하기 위해 해수와 알칼리성 산업부산물인 제지슬러지소각재(PSA)를 사용하였다. 다양한 실험을 통해 해수와 PSA를 이용한 직접탄산화 반응의 최적 용매의 양(해수와 PSA의 혼합비)과 반응시간을 찾았고, PSA를 이용한 직접탄산화 반응에 해수와 초순수를 각각 용매로 사용했을 때의 이산화탄소 저장량을 비교하였다. 이산화탄소 저장량은 탄산화반응 후 고체증가량과 열중량분석 결과를 이용해서 계산하였다. 실험에 사용한 PSA는 미세하고 67.2%의 칼슘을 포함하였다. $25^{\circ}C$, 1기압에서 해수를 PSA와 혼합하여 이산화탄소를 0.05 L/min 유량으로 주입하는 탄산화반응의 최적 용매의 양과 반응시간은 각각 5 mL/g, 2시간이었다. 해수와 초순수를 용매로 사용해서 PSA와 각각 혼합한 다음 탄산화했을 때, 이산화탄소 저장량은 각각 113, $101kg\;CO^2/(ton\;PSA)$이었다. 해수를 사용하여 탄산화한 고체는 대부분 calcite 형태의 탄산칼슘과 소량의 탄산마그네슘으로 구성되어있었고, 초순수를 사용했을 때의 고체도 calcite 형태의 탄산염임을 확인하였다.