• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.9
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• pp.513-518
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• 2009

The building HVAC systems generally have very different qualities of performance and durability with the superintendent's interest in or capability of management and maintenance of them. The poor management of these systems finally lead to the shortening of the life expectancy and result in the increase of operating cost and energy consumption due to their low efficiencies. So it is necessary to develop tools to maintain adequately and to operate efficiently various building service equipments in order to cope with actively the global environment problems and energy crises. In this study the LCC based calculation program and package were developed, which could be used for analyses of the economic performance and determination of the reasonable maintenance time and methods of building HVAC systems.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.847-852
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• 2007

This study investigated an efficient method for the extraction of astaxanthin from the red yeast Xanthophyllomyces dendrorhous. The extraction process comprised three steps: 1) cultivating the yeast; 2) treating the yeast culture suspension with microwaves to destroy the cell walls and microbodies; and 3) drying the yeast and extracting the astaxanthin pigment using ethanol, methanol, acetone, or a mixture of the three as the extraction solvent. Ultimately, various treatment tests were performed to determine the conditions for optimal pigment extraction, and the total carotenoid and astaxanthin contents were quantified. A frequency of 2,450 MHz, an output of 500 watts, and irradiation time of 60 s were the most optimum conditions for yeast cell wall destruction. Furthermore, optimal pigment extraction occurred when using a cell density of 10g/l at $30^{\circ}C$ over 24 h, with a 10% volume of ethanol.

• Journal of Mushroom
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• v.21 no.3
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• pp.110-117
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• 2023

Cordycepin (3'-deoxyadenosine) is a nucleoside analog known for its diverse range of biological activities. This study investigated the effect of different types of sawdust on the production of the bioactive compound cordycepin. The results of the study showed that different types of wood sawdust affected the biosynthesis of cordycepin and a significant increase was observed when the conventional SDB medium was replaced with 1% NaOH treated pine sawdust. To optimize cordycepin production from Paecilomyces tenuipes in a medium containing 1% NaOH-pretreated pine sawdust, we employed Response Surface Methodology (RSM) in its Box-Behnken design (BBD) canonical form. The optimal conditions were determined as follows: a particle size of 109.5111-mesh (140 ㎛) for 1% NaOH-pretreated pine sawdust, an input weight of 21.1679 g/L, and an incubation time of 73.8423 hours. According to our model, this combination is expected to yield a maximum cordycepin content of 896.1428 ㎍/mL. Experimental validation of this prediction was performed using the suggested optimal conditions, resulting in an average cordycepin content of 922.6771 ㎍/mL across three replicates, thus confirming the model's accuracy.

• Food Science of Animal Resources
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• v.42 no.6
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• pp.942-952
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• 2022

To establish a pre-plating method of chicken satellite cells with high purity, pre-plating was performed under culture conditions of 37℃ and 41℃, and the pre-plating time was set from a total of 3 hours to 6 hours in consideration of the cell attachment time. The purity of the cells was confirmed by staining paired box protein 7 (Pax7) after proliferation, and Pax7 expression was the highest in culture flasks shaken for 2 hours after incubation at 41℃ for 2 hours to prevent the attachment of satellite cells (p<0.05). Also, when pre-plating and proliferation were performed at 37℃ and 41℃, the Pax7 expression rate was higher at 41℃. The differentiation capabilities of the three groups (T3, T6, and T7) with high Pax7 expression were compared and the fusion index (%) and myotube formation area (%) determined by myosin heavy chain (MHC) staining was calculated. The T6 and T7 groups, which were cultured at 41℃, showed significantly higher values than the T3 group (p<0.05). There was no significant difference in the expression of Pax7 and MHC between the T6 and T7 groups (p>0.05). These results suggest that pre-plating at 41℃ for a total of 4 hours was the most efficient in terms of cost and time for purifying chicken satellite cells for cultured meat.

• Journal of Ocean Engineering and Technology
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• v.17 no.6
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• pp.16-22
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• 2003

In this paper, the method of determining the economically-optimal design section of rubble mound breakwater, using ADS program, was studied to supplement the deterministic approach. First of all, the design waves are computed, according to the return periods, using the Weibull distribution from the data of waves at the location of the breakwater. In order to take an optimal section, according to the return periods, the ADS program was used. The restriction conditions and objective functions are decided from the references of the specifications and standard manuals for Coastal and Harbor Construction Work. Results from this study support the ADS program as an appropriate method for determining the economically-optimal section of rubble mound breakwater, comparing the construction costs and the initial and damage repair costs for its life time.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.792-796
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• 2009

Determining the optimal number of cluster is an important issue in research area of data clustering. It is choosing the cluster validity method and finding the cluster number where it optimizes the cluster validity. In this paper, an efficient heuristic for determining optimal number of cluster using clustering balance is proposed. The experimental results using k-means at artificial and real-life data set show that proposed algorithm is excellent in aspect of time efficiency.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.3
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• pp.320-331
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• 2013

Omija, the major material of omigalsu, has liver protective and antioxidant effects, while mung bean has detoxification effects. A series of studies were conducted to standardize the traditional recipe for omigalsu to develop traditional functional drinks made from Omija extract and mung bean juice. Study 1 was designed to determine the optimal conditions for Omija extraction and mung bean juice. A higher water temperature and longer immersion time was associated with higher, free sugar and organic acid contents of omija extract; however, sensory evaluation revealed that the optimal extraction conditions for the highest acceptability, proper taste and red tone were $23^{\circ}C$ and 18 hrs of immersion. Conversely, the pH of the mung bean juice produced by varying the immersion time (5 hr, 11 hr, 17 hr) was found to be neutral, containing small levels of organic acid and free sugar, and showing a yellow tone. The results of the sensory evaluation also showed that the optimal conditions for taste, flavor and yellowness of mung bean juice was 5-hour-long immersion. Study 2 was designed to determine the optimum mixing ratio of omigalsu concentrate. Sensory evaluation revealed that the contents of sugar and total free sugar were highest when the mixing ratio among omija extract, mung bean juice and sugar was 1:1:20%, indicating that these conditions produced the most attractive color and highest overall acceptability. Study 3 was designed to determine the optimum dilution magnification for omigalsu. Sensory evaluation during summer revealed that the omigalsu produced by mixing 54 g of omigalsu concentrate into 200 cc water of $4^{\circ}C$ or $80^{\circ}C$ was most preferred, while during winter. Overall, the optimum dilution magnification for omigalsu was 4.7~5.4.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.102-108
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• 2015

Agricultural cultivation papers treated with water repellent were investigated in order to analyse mechanical properties and durability. The water repellency was optimal when papers are treated with Wb and Sa water repellents. Also, WCPs with 5% water repellent were more effective than those of 3 and 10%. In addition, water repellency of WCPs with Wb and Sa water repellents were kept constant in correlation with aging time. Finally, WCP with Wb water repellent possesses efficiency in terms of mechanical properties and durability.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.305-312
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• 1999

This study is intended to propose a systematic and practical life cycle cost(LCC) model for the development of the reliability-based seismic safety and cost-effective performance criteria for design and upgrading of long-span PC bridges. The LCC models consist of five cost functions such as initial cost, repair/replacement cost, human losses, road user cost, and indirect losses of regional economy. The proposed model Is successfully expressed in temrs of Park-Ang damage indices and life cycle damage probability obtained from SMART-DRAIN-2DX which is an existing algorithm for nonlinear time history analysis. The proposed LCC model is successfully applied to a viaduct constructed by PSM, in Seoul. Based on the observations, the proposed systematic procedure for the formulation of LCC model may be useful for the development of the reliability-based seismic safety and cost-effective performance criteria for design and upgrading of long-span PC bridges.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.971-976
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• 2004

The management of railroad structures is more difficult and complicate because there are many structures such as rail, bridge, tunnel, station, and so on. Therefore, LCC(Life Cycle Cost) analysis of railroad structures as public infrastructure must contain a maintenance cost as well as an initial cost in order to make a more effective management during the life cycle on the design phase. This paper presents a cost classification scheme considering user costs such as value of delayed time of passenger and freight. Also, in this study it is developed a probabilistic life cycle cost(PLCC) analysis model of railroad structures taking into account uncertainties and variations of input variables in order to analyze LCC. It may be stated that the model proposed in this study can greatly contribute to the making optimal decision, the estimate of the maintenance cost and the allocate of budget in the project of railroad structures.