• Wind and Structures
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• v.26 no.5
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• pp.293-304
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• 2018

A numerical study is conducted on the flow characteristics of a rectangular cylinder (chord-to-width ratio C/W = 2 - 10) mounted close to a rigid wall at gap-to-width ratios G/W = 0.25 - 6.25. The effects of G/W and C/W on the Strouhal number, vortex structure, and time-mean drag and lift forces are examined. The results reveal that both G/W and C/W have strong influences on vortex structure, which significantly affects the forces on the cylinder. An increase in G/W leads to four different flow regimes, namely no vortex street flow (G/W < 0.75), single-row vortex street flow ($0.75{\leq}G/W{\leq}1.25$), inverted two-row vortex street flow ($1.25<G/W{\leq}2.5$), and two-row vortex street flow (G/W > 2.5). Both Strouhal number and time-mean drag are more sensitive to C/W than to G/W. For a given G/W, Strouhal number grows with C/W while time-mean drag decays with C/W, the growth and decay being large between C/W = 2 and 4. The time-mean drag is largest in the single-row vortex street regime, contributed by a large pressure on the front surface, regardless of C/W. A higher C/W, in general, leads to a higher time-mean lift. The maximum time-mean lift occurs for C/W = 10 at G/W = 0.75, while the minimum time-mean lift appears for C/W = 2 at the same G/W. The impact of C/W on the time-mean lift is more substantial in single-row vortex regime. The effect of G/W on the time-mean lift is larger at a larger C/W.

• Kyungpook Mathematical Journal
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• v.63 no.1
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• pp.123-129
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• 2023

For an ordered set W = {w₁, w₂, . . . , w_k} of vertices and a vertex v in a connected graph G, the k-vector r(v|W) = (d(v, w₁), d(v, w₂), . . . , d(v, w_k)) is called the metric representation of v with respect to W, where d(x, y) is the distance between the vertices x and y. A set W is called a resolving set for G if distinct vertices of G have distinct metric representations with respect to W. The minimum cardinality of a resolving set for G is its metric dimension dim(G), and a resolving set of minimum cardinality is a basis of G. The corona product, G ⊙ H of graphs G and H is obtained by taking one copy of G and n(G) copies of H, and by joining each vertex of the ith copy of H to the ith vertex of G. In this paper, we obtain bounds for dim(G ⊙ K₁), characterize all graphs G with dim(G ⊙ K₁) = dim(G), and prove that dim(G ⊙ K₁) = n - 1 if and only if G is the complete graph K_n or the star graph K_1,n-1.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.1
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• pp.15-23
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• 1985

Growth response and evapotranspiration of tobacco as to each soil moisture condition treated with different height of ground water table such as 30cm, 100cm, 170cm, and 230cm were investigated. The results obtained were as follows; 1. Soil water potential in the rhizosphere (25cm depth from surface) treated with ground water table (G.W.T) of 230 cm was less than -6.5 bar at 60 days after transplanting. 2. Dry weight of leaves per plant was the highest in the pot treated with 100 cm G.W.T and was the lowest in the pot treated with 230 cm G.W.T.. Leaves/Stem ratio of dry weight was the lowest in the pot treated with 230 cm G.W.T. This would show that extension of leaves as compared with elongation of stem was suppressed. .3. In the roster stress condition of 230 cm G.W.T., extension of leaves was continued until the latter growth stage, Relative growth rate of leaf area per plant of the pot with 30 cm G.W.T. was the highest through all growth period after fixation of G.W.7., but owing to lower density of leaf, the dry weight of leaves per plant was less rather than that of the pot with 170 cm G.W.T. at 64 days after transplanting. 4. The highest evapotranspiration per plant per day was shown at the 45th day after transplanting in the pots with 30cm and 100cm G.W.T. and at 60 days in the pots with 170cm and 230cm G.W.T respectively. 5. In the soil moisture conditions with 30cm and 100cm G.W.T., evapotranspiration per plant per hour was much higher in the daytime that at night as well as in clear day than in rain-cloudy day owing to loner relative humidity , but in the water stress condition with 230 cm G.W.T., that was much lower. 6. Total evapotranspiration per plant during the whole growing period of 64 days was in order of 30cm > 100 cm > 170 cm > 230 cm G.W.T.. Total evapotranspiration for 34 days after fixation of G.W.T was much higher at night than in the daytime in case of water stress conditions i.e 170cm and 230cm G.W.T. but in normal condition of the pots with 30cm and 100cm G.W.T. that was much higher in the daytime than at night. 7. Leaf water potential of the 3rd and 6th leaf from top at 64 days after transplanting was in order of 100cm > 30 cm > 170cm > 230cm G.W.T. The reason why leaf water potential in the pot with 30cm was less than that in the pot with 100cm G.W.T. would be the abnormal turgidity with low density of cell substrates by the excess water absorption in the pot with 30cm G.W.T..

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.51-57
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• 2000

Concentrations of cadmium, copper and zinc were determined in three molluscan species including Sacculosiphonaria japonica, Reishia clavigera and Crassostrea gigas to assess heavy metal contamination in the Onsan Bay. The range of cadmium concentrations were 3.83∼39.67 ㎍/g d.w. in S. japonica, 7.47∼103.47 ㎍/g d.w. in R. clavigera, 1.32∼92.17 ㎍/g d.w. in C. gigas. Concentration of cadmium at contaminated site in C. gigas was 70 folds higher than that of reference site. The range of copper concentrations were 22.92∼1287.56 ㎍/g d.w. in S. japonica, 37.53∼656.97 ㎍/g d.w. in R. clavigera, 161.50∼3208.52 ㎍/g d.w. in C. gigas. The concentration of copper at contaminated site in S. japonica was 56 folds higher than that of reference site. The range of zinc concentrations were 93.48∼377.40 ㎍/g d.w. in S. japonica, 423.65∼1075.57 ㎍/g w. in R. clavigera, 2018.13∼22275.00 ㎍/g d.w. in C. gigas. The difference of zinc concentrations between reference site and contaminated site was relatively small than those of cadmium and copper in all the species tested. The largest difference was 11 folds in C. gigas. In the present work, we confirmed that all of these species, S. japonica, R. clavigera and C. gigas, could be used as biological indicators to monitor heavy metal contamination.

• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.408-412
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• 2008

This research was designed to investigate the antioxidant activities and tyrosinase inhibitory effects of guava (Psidium guajava L.) leaf. Total phenol content was obtained from guava leaf extract of 19.0 (g/100g, D.W.). The crude extract exhibited significantly antioxidant activities (IC50value $102.5{\mu}g/ml$, free radical scavenging; $49.4{\mu}g/ml$, SOD like activity). The crude extract of guava leaf was fractionated into four partition layers; hexane (G-H), ethyl acetate (G-E), butanol (G-B) and water (G-W) layer. The extracts of G-E, G-B, G-W showed high radical scavenging activities of over 50% at $100{\mu}g/ml$. SOD like activities of G-E, G-B, G-W were revealed, as 81.8%, 84.7%, 65.3% at $100{\mu}g/ml$, while those of G-H did not showed the effectively. The crude extract of guava leaf showed high tyrosinase inhibitory effect as 60.8% at 1mg/ml, the measurement of G-E, G-B, G-W were 65.2%, 62.8%, 51.6% and that of G-H was not effective. These results indicate that useful bioactive substances exist in the guava leaf extracts, especially G-E, G-B. And the guava leaf has the potential of being developed into health related products.

• Journal of Mushroom
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• v.21 no.4
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• pp.222-227
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• 2023

Mushrooms have a unique taste and aroma, so in the processing of mushroom products with other ingredients, a separate pre-processing step is often taken to eliminate the mushroom aroma. In this study, we analyzed the changes in the concentration of volatile compounds according to drying conditions to promote the activation of processing using the fruiting bodies of yellow oyster mushrooms(Pleurotus citrinopileatus) and pink oyster mushrooms(P. djamor). The caps and stipes of yellow oyster and pink oyster mushrooms were separated and freeze-dried at -70℃ for 120 hours. Subsequently, they were hot air-dried at temperatures of 40, 50, 60, and 70℃ for 24, 24, 16, and 12 hours, respectively. The dried samples were pulverized and quantitatively analyzed by SPME-GC-MS. In the case of yellow oyster mushrooms, the concentration of t-2-nonenal in caps and stipes during freeze-drying was 164.43 ㎍/g d.w. and 174.80 ㎍/g d.w., respectively, whereas during hot air-drying, it significantly decreased to 0.35~3.41 ㎍/g d.w. and 0.98~59.88 ㎍/g d.w. In a similar manner, for pink oyster mushrooms, the concentration of 1-octen-3-ol during freeze-drying in caps and stipes was 31.05 ㎍/g d.w. and 176.17 ㎍/g d.w., respectively, whereas during hot air-drying, it significantly decreased to 1.59~9.66 ㎍/g d.w. and 1.96~15.77 ㎍/g d.w. Furthermore, most volatile compounds showed a tendency to decrease in concentration as the temperature during hot air-drying increased.

• Journal of Sasang Constitutional Medicine
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• v.1 no.1
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• pp.125-138
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• 1989

In order to investigate the effect of Row ginseng (Ra. G.; from $K{\acute{u}}msan$ province, Korea), White ginseng (W.G.; from $K{\acute{u}}msan$ province, Korea), and Red ginseng (Re. G.; form $K{\acute{u}}msan$ province, Korea) on immune response, the author used ICR mice having a body weight of about 20g as experimental animals dividing them into four groups-Saline, Ra. G, W.G., Re. G group. Delayed type hypersensitivity(DTH) and rosette forming cells(RFC) for cell-mediated immune response, hemagglutinin(HA) titers, hemolysin (HL) titers for humoral immune response were measured at 24 hours after challenge, The results were summarized as follows: 1) DTH was increased in all of the treated group as compared with the Saline group, with statistical significance(W.G.> Re. G. > Ra. G.). 2) RFC was increased in all of the treated group as compared with the Saline group, with statistical significance(W.G. > Re. G. > Ra. G.). 3) HA titer was increased in all of the treated group as compared with the Saline group, with statistical significance (Re. G.> W. G.> Ra. G.). 4) HL titer was increased in all of the treated group as compared with the Saline group, with statistical significance (Re. G. > W. G.> Ra. G.). Through the experimental study in ICR mice, these findings suggest that Raw ginseng, White ginseng and Red ginseng enhance both cell-mediated and humoral immune response with statistical significance.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.227-235
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• 2015

In this paper, I propose a linear time algorithm devised to produce exact solution to NP-complete maximum clique problem. The proposed algorithm firstly, from a given graph G=(V,E), sets vertex $v_i$ of the maximum degree ${\Delta}(G)$ as clique's major vertex. It then selects vertex $v_j$ of ${\Delta}(G)$ among vertices $N_G(v_i)$ that are adjacent to $v_i$, only to determine $N_G(v_i){\cap}N_G(v_j)$ as candidate cliques w and $v_k$. Next it obtains $w=w{\cap}N_G(v_k)$ by sorting $d_G(v_k)$ in the descending order. Lastly, the algorithm executes the same procedure on $G{\backslash}w$ graph to compare newly attained cliques to previously attained cliques so as to choose the lower. With this simple method, multiple independent cliques would also be attainable. When applied to various regular and irregular graphs, the algorithm proposed in this paper has obtained exact solutions to all the given graphs linear time O(n).

• Electronics and Telecommunications Trends
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• v.32 no.4
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• pp.89-95
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• 2017

영국은 2017년 3월 5G N/W 조기구축을 위한 정부차원의 전략방향 보고서(A 5G Strategy for UK)를 발표하였다. 영국은 5G 인프라가 4차 산업혁명의 촉진제 역할을 할 것이며, 5G로 인한 경제적 파급 효과가 2030년경에 1,980억 파운드 달할 것으로 예상한다. 이러한 전망에 따라 영국 정부는 5G 테스트베드 구축, Small Cell 및 백홀 구축 지원, 주파수 정책방향 제시 등 5G N/W 조기구축 환경을 조성하여 이동통신사의 적극적인 투자를 유인할 계획이다. 아울러 산업계, 학계, 지역정부와 협력하여 다양한 산업분야에서의 5G 활용 방안을 도출하며, 5G 상용화 이전에 해결해야 할 과제를 정비함으로써 영국이 5G 분야에서 글로벌 리더가 되고자 하는 목표를 제시하고 있다. 본고에서는 영국이 4차 산업혁명에 대비하여 제시하는 5G N/W 투자 촉진 전략을 소개하고자 한다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.303-313
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• 2015

Titrated extract of Centella asiatica (TECA), which is poorly soluble in water is well known for wound healing and anti wrinkle agent. This study was conducted to find the optimum condition for the preparation of water in oil in water ($W_1/O/W_2$) emulsion containing TECA. Solubility of TECA were measured by UV spectrophotometer. 2.55 g of TECA was dissolved in solution composed of dipropylene glycol (40.0 g), ethanol (20.0 g), and water (10.0 g). Factors affecting stability of the emulsions ($W_1/O$, $W_1/O/W_2$) was investigated. The optimum conditions for the preparation of $W_1/O$ emulsion was composed of dipropylene glycol : ethanol : water : TECA in a weight ratio of 40.0 : 20.0 : 10.0 : 2.5 for water phase and squalane : cetyl PEG/PPG-10/1 dimethicone : cetearyl alcohol in a weight ratio of 22.5 : 4.0 : 2.5 for oil phase. The optimum conditions for the preparation of $W_1/O/W_2$ multiple emulsion was composed of water : $W_1/O$ emulsion : polysorbate 80 : carbomer : triethanolamine in a weight ratio of 55.8 : 40.0 : 4.0 : 0.1 : 0.1.