• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1749-1757
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• 2010

This paper considers the cost minimization problem to satisfy QoS (Quality of Service) requirements for a given network, in particular when communication resources to each link can be additionally assigned. For the purpose of quantifying QoS requirements such as data transfer delay and packet loss, we introduce the cost function considering both the link utilization factor and the additionally assigned resource. To minimize this cost function, we firstly formulate a Basic Capacity Planning (BCP) problem, a special case of Network Utility Maximization (NUM). We show that the solution of this BCP problem cannot be optimal via a counter example. In this paper, we suggest the cross-layer design of both additionally assigned resource and routing path, whose initial values are set to the result of BCP problem. This cross-layer design is based on a heuristic approach which presents an effective way to plan how much communication resources should be added to support the QoS requirements in future. By simulation study, we investigate the convergence of the cost function in a more general network topology as well as in a given simple topology.

• Journal of Korea Water Resources Association
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• v.30 no.4
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• pp.347-355
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• 1997

In this study, the applicability of genetic algorithms into the parameter estimation of storage function method for flood routing model is investigated. Genetic algorithm is mathematically established theory based on the process of Darwinian natural selection and survival of fittest. It can be represented as a kind of search algorithms for optima point in solution space and make a reach on optimal solutions through performance improvement of assumed model by applying the natural selection of life as mechanical learning province. Flood events recorded in the Daechung dam are selected and used for the parameter estimation and verification of the proposed parameter estimation method by the split sample method. The results are analyzed that the performance of the model are improved including peak discharge and time to peak and shown that the parameter Rsa, and f1 are most sensitive to storage function model. Based on the analysis for estimated parameters and the comparison with the results from experimental equations, the applicability of genetic algorithm is verified and the improvements of those equations will be used for the augmentation of flood control efficiency.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.247-252
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• 2015

Aronia (Black chokeberry, Aronia melanocarpa) belonging to the Rosaceae family, is native to eastern North America. Aronia contain high levels of flavonoids, mostly anthocyanins and proanthocyanidins, which are known as condensed tannins. The dominant proanthocyanidins in aronia are (-)-epicatechin and (+)-catechin. The concentration of proanthocyanidins in aronia is higher than in other berries, however due to the astringent taste it is not desirable for consumption. Therefore, the purpose of this study is to evaluate the effect of aronia on the reduction in tannins by yeast isolated from regional Jeotgal. We isolated strains of yeast with high ${\beta}$-glucosidase activity from Jeotgal, with the MTY2 strains exhibiting a reduction in final tannin concentration according to thin layer chromatography (TLC) analysis. MTY2 was confirmed as Kazachstania servazzii using an 18S rDNA sequence and named as K. servazzii MTY2. K. servazzii MTY2 showed most significant growth when K. servazzii MTY2 was cultured in a solution of 10% (w/v) glucose, 3% (w/v) tryptone and 0.1% (w/v) sodium chloride. According to the high performance liquid chromatography (HPLC) analysis, the (+) - catechin peak is present, but (-) - epicatechin peak was reduced at culture condition added with 10% glucose in medium.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.5
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• pp.177-188
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• 2018

The scale of graph data has been increased rapidly because of the growth of mobile Internet applications and the proliferation of social network services. This brings upon the imminent necessity of efficient distributed and parallel graph processing approach since the size of these large-scale graphs are easily over a capacity of a single machine. Currently, there are two popular parallel graph processing approaches, vertex-centric graph processing and block centric processing. While a vertex-centric graph processing approach can easily be applied to the parallel processing system, a block-centric graph processing approach is proposed to compensate the drawbacks of the vertex-centric approach. In these systems, the initial quality of graph partition affects to the overall performance significantly. However, it is a very difficult problem to divide the graph into optimal states at the initial phase. Thus, several dynamic load balancing techniques have been studied that suggest the progressive partitioning during the graph processing time. In this paper, we present a load balancing algorithms for the block-centric graph processing approach where most of dynamic load balancing techniques are focused on vertex-centric systems. Our proposed algorithm focus on an improvement of the graph partition quality by dynamically reassigning blocks in runtime, and suggests block split strategy for escaping local optimum solution.

• Journal of Life Science
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• v.25 no.2
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• pp.206-213
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• 2015

Sunsik has been popular as well-being and healthy food to some Asian people, but it still has a limit to other foreigners because of its taste and appearance. This study tried to modify Sunsik into smoothie type for foreigners and investigate its physicochemical characteristics. Germinated black and brown rice was prepared. The germination condition of two cereals was steeping for 24 hr at room temperature, and then germinating for 24 hr at $30^{\circ}C$. After germination, the ${\alpha}$-amylase activity of germinated grains was 13~15 times higher than before germination. The enzyme activity of brown rice was 9.16 CU/g, but germinated brown rice was 152.63 CU/g. In case of black rice, enzyme activity before germination was 7.47 CU/g, and enzyme activity after germination was 97.96 CU/g. The lactic acid bacteria was grown in 50 g germinated brown rice powder with 100 ml malt solution, 30 g tomato juice, and 1.5 g rice bran. After manufacturing beverage using milk and Sunsik and the cell count of lactic acid bacteria was $1.3{\times}10^5CFU/ml$ enough to use starter. According to sensory test, the optimal concentration of Sunsik smoothie was 30 g Sunsik in 200 ml of milk. The viscosity was $5.97{\pm}1.2$ centipoise. The color of Sunsik beverage was evaluated as L value : $63.50{\pm}0.41$, a value: $-0.35{\pm}0.06$, and b value: $8.85{\pm}0.19$.

• Journal of Life Science
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• v.19 no.8
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• pp.1033-1038
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• 2009

Maximal productions of gellan by Sphingomnas paucibilis NK2000 from 20 g/l glucose and 10 g/l soybean pomace were 7.46 g/l in a flask and 7.35 g/l in a 7 l bioreactor, when the initial pH of media was 6.8. Maximal production of gellan in a 7 l bioreactor under pH control by sodium hydroxide was 8.42 g/l, whereas that under control by potassium phosphate was 8.50 g/l. The optimal concentration of potassium phosphate in a medium for production of gellan by S. paucibilis NK2000 was found to be 5.0 g/l. Maximal production of gellan in a medium containing 5.0 g/l potassium phosphate without pH control was 8.93 g/l in a 7 l bioreactor. In this study, a simple process without pH control was developed to enhance the production of gellan, with optimized concentration of potassium phosphate in the medium.

• The Korean Journal of Applied Statistics
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• v.30 no.4
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• pp.539-553
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• 2017

We propose a multi-state model to analyze semi-competing risks data with interval-censored or missing intermediate events. This model is an extension of the three states of the illness-death model: healthy, disease, and dead. The 'diseased' state can be considered as the intermediate event. Two more states are added into the illness-death model to incorporate the missing events, which are caused by a loss of follow-up before the end of a study. One of them is a state of the lost-to-follow-up (LTF), and the other is an unobservable state that represents an intermediate event experienced after the occurrence of LTF. Given covariates, we employ the Lin and Ying additive hazards model with log-normal frailty and construct a conditional likelihood to estimate transition intensities between states in the multi-state model. A marginalization of the full likelihood is completed using adaptive importance sampling, and the optimal solution of the regression parameters is achieved through an iterative quasi-Newton algorithm. Simulation studies are performed to investigate the finite-sample performance of the proposed estimation method in terms of empirical coverage probability of true regression parameters. Our proposed method is also illustrated with a dataset adapted from Helmer et al. (2001).

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.648-656
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• 1997

Thermal treatment of soymilk residue was carried out at 140, 150, and $160^{\circ}C$ for possible use as a raw material for dietary fiber, and some physicochemical properties of the extracts were investigated. Soluble dietary fiber(SDF) content of the extracts prepared under optimal conditions was more than 30% suggesting the conversion of insoluble dietary fiber to SDF. The main sugar components of the extracts were glucose, galactose, and arabinose. Analysis of the moelcular weight distribution by high performance size exclusion chromatography revealed that the proportion of high molecular weight fraction decreased and that of middle-sized polymer increased as the extraction temperature increased. The viscosity of aqueous solution of the extracts decreased with an increase in extraction temperature, but showed no trend as pH changed. The solubility increased with extraction temperature showing the highest at $160^{\circ}C$. The extract at $140^{\circ}C$ had the biggest calcium-binding capacity, which correlated with the changes in viscosity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.4
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• pp.1-9
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• 2020

This study conducted to understand effects of CA (CaAl₂O₄) and CA₂ (CaAl₄O₇) ratio on chloride binding ability and compressive strength and pore structure of cement mortar incorporating mixture of CA and CA₂. The Portland cement based specimens were mixed with the clinkers CA and CA₂, and these calcium aluminate clinker mixture were replaced 0, 5, 10% by weight of cement. After all the test specimens were cured for 28 days under water curing, they were immersed in the distilled water and NaCl solution. As a result, 28 days compressive strength of all specimens was similar, and As the replacement ratio of calcium aluminate clinker in the specimen increased, Friedel's salt production tended to increase. However, it was dependent on the amount of Al₂O₃ in the level of 5% replacement and CA ratio in the level of 10% replacement. Through equilibrium isotherm result, it was also indicated that as replacement ratio of calcium aluminate clinker in cement matrix increased, chloride binding capacity was improved, and chloride penetration was suppressed. In this study, the specimen replaced with 10% of the calcium aluminate clinker mixture (CA 39%, CA₂ 60%) was remarkable to control chloride attack. We figured out necessity to understand optimal CA/CA₂ ratio to effectively apply CA₂ as a sustainable building material by improving the chloride binding ability in Portland cement based system.

• Korean Journal of Plant Resources
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• v.30 no.1
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• pp.50-57
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• 2017

This study aimed to investigate the morphological characteristics and optimal germination conditions in seeds of Arabis pendula L., a traditionally edible and medicinal plant. The external seed shape was circular-obovate with narrow wings and dark brown. The seed length and width were 1.25 mm and 1.47 mm, respectively. The seeds were exalbuminous and the embryo was a bent type. Seed germination was the highest (49.7%) at $20^{\circ}C$ under dark conditions among the various temperature and light conditions applied. However, under the dark condition, the seedling was weak, overgrown, and the cotyledons were small and folded. To improve the germination and growth of seedlings, the seeds were pre-treated with $GA_3$ solutions of varying concentrations (0, 200, 500, and 1,000 mg/L). The seed germination and seedling growth were effectively improved by $GA_3$ pre-treatment. The germination rate was the highest (97.3%), mean germination time was the shortest (8.1 days), and a vigorous growth of seedlings was observed upon pre-soaking the seeds in 500 mg/L $GA_3$ solution. In conclusion, the best method for germination was pre-soaking in 500 mg/L $GA_3$ ($4^{\circ}C$, dark, 24 h) and incubating the seeds at $20^{\circ}C$ for 15 days.