• Journal of the Korean Society of Systems Engineering
• /
• v.5 no.1
• /
• pp.7-20
• /
• 2009

This paper describes a case study on the R&D programs of fighter and attacker aircraft such as F-22A, F/A-18E/F, and T/A-50. F-22A and F/A-18E/F were developed in same age. The performance of each program was, however extremely different. F-22A program results in a lot of cost overrun and schedule delay. On the other hand F/A-18E/F program met the cost, schedule, and performance goals. In the T/A-50 program with a super-sonic advanced trainer, T-50 was also developed successfully on planned cost and time by Korea Air-force and KAI. This paper derives key elements for the success of the military aircraft R&D program through lessons learned from th e case study. Each program is analyzed in terms of its background, planning and management.

• Microbiology and Biotechnology Letters
• /
• v.39 no.1
• /
• pp.29-36
• /
• 2011

Pseudomonas aeruginosa is an opportunistic pathogen that causes various infections on urinary track, cornea, respiratory track, and burn wound site, and mainly relies on quorum sensing (QS) for its virulence. To control the infectivity of P. aeruginosa, we previously synthesized the structural analogues of a major QS signal, N-3-oxododecanoyl homoserine lactone (3OC12-HSL) to use as a QS inhibitor. Two of them (5b and 5f) had been confirmed to have an inhibitory effect on LasR, a major QS signal receptor of P. aeruginosa in the screening by the recombinant Escherichia coli reporter. To further evaluate these compounds, we tested their efficacy to control the QS and virulence of P. aeruginosa. Unlike the result from E. coli reporter, both 5b and 5f failed to affect the LasR activity in P. aeruginosa, but instead they selectively affected the activity of QscR, another 3OC12-HSL receptor of P. aeruginosa. Interestingly, their effect on QscR was complex and opposite to what we obtained with E. coli system. Both 5b and 5f enhanced the QscR activity at the low concentration range (< 10 ${\mu}m$), but high concentration of 5f (${\approx}$1 mM) strongly inhibited QscR. While 5b and 5f didn't affect the production of proteases, the key virulence factor, they significantly reduced the biofilm formation that is important in mediating chronic infections. Especially, 5f inhibited the initial attachment of P. aeruginosa, rather than the biofilm maturation. Based on our results, we suggest that 5f can be applied for an anti-biofilm agent without increasing virulence of P. aeruginosa.

• Food Science of Animal Resources
• /
• v.31 no.2
• /
• pp.273-279
• /
• 2011

Various honeys from different sources were analyzed using an electronic nose based on a mass spectrometer. Various honeys were separated with different mixing ratios. Wild honey and artificial honey were blended at ratios of 100:0, 95:5, 90:10, 85:15, 80:20, 75:25, and 70:30, respectively. Data obtained from the electronic nose were used for discriminant function analysis (DFA). The DFA plot indicated a significant separation of honey from different sources. As the concentration of artificial honey increased, the first discriminant function score (DF1) moved from positive to negative (DF1: $r^2$=0.9962, F=490.6; DF2: $r^2$=0.9128, F=19.44). Furthermore, when acacia honey was mixed with artificial honey and separated with the mixing ratios, the DF scores were: DF1: $r^2$=0.9957, F=396.64; DF2: $r^2$=0.9447, F=29.3. When artificial honey was added to wild honey, it was possible to predict the following equation; DF1= -0.106${\times}$(concentration of artificial honey)+0.426 ($r^2$= 0.96). For acacia honey, the DF1= -0.112${\times}$(concentration of artificial honey)+0.434 ($r^2$=0.968).

• Journal of the Korean Mathematical Society
• /
• v.52 no.5
• /
• pp.991-1001
• /
• 2015

In this work we obtain conditions for nonspecial line bundles on general ${\kappa}$-gonal curves failing to be normally generated. Let L be a nonspecial very ample line bundle on a general ${\kappa}$-gonal curve X with ${\kappa}{\geq}4$ and $deg\mathcal{L}{\geq}{\frac{3}{2}}g+{\frac{g-2}{{\kappa}}}+1$. If L fails to be normally generated, then L is isomorphic to $\mathcal{K}_X-(ng^1_{\kappa}+B)+R$ for some $n{\geq}1$, B and R satisfying (1) $h^0(R)=h^0(B)=1$, (2) $n+3{\leq}degR{\leq}2n+2$, (3) $deg(R{\cap}F){\leq}1$ for any $F{\in}g^1_k $. Its converse also holds under some additional restrictions. As a corollary, a very ample line bundle $\mathcal{L}{\simeq}\mathcal{K}_X-g^0_d+{\xi}^0_e$ is normally generated if $g^0_d{\in}X^{(d)}$ and ${\xi}^0_e{\in}X^{(e)}$ satisfy $d{\leq}{\frac{g}{2}}-{\frac{g-2}{\kappa}}-3$, supp$(g^0_d{\cap}{\xi}^0_e)={\phi}$ and deg$(g^0_d{\cap}F){\leq}{\kappa}-2$ for any $F{\in}g^1_k$.

• Journal of Korean Public Health Nursing
• /
• v.13 no.2
• /
• pp.143-160
• /
• 1999

The purpose of this descriptive survey study was to examine the following items. 1) Score distribution of life satisfaction. powerlessness. perceived health status and self-esteem 2) Demographic characteristics and the affection of socioeconomic characterictics to life satisfaction. powerlessness. perceived health status and self-esteem 3) Correlationship between life satisfaction. powerlessness. perceived health status and self-esteem 4) Determining the factors affecting life satisfaction The subjects were 167 urban elderly people. Data were collected from May to July in 1998 using the questionaires. The data were analyzed by mean. ANOVA. Pearson correlation coefficient and stepwise multiple regression with SPSS win 7.5 program. The results were as follows : 1) The degree of life satisfaction and powerlessness were relatively low with the mean score of 42.4 and 39.79 respectively. and perceived health status and self-esteem were relatively high with the mean score of 3.15 out of 5 and 27.3 respectively. 2) There were no significant differences between demographic characteristics and life satisfaction. Education(F=2.91. p=0.02), previous employment(F=2.23. p=0.03) and marital status(F=3.85. p=0.04) showed significant differences in the relationship between demographic characteristics and powerlessness. Sex(F=6.40. p=0.0l). education(F=3.30. p=0.0l). marital status(F=7.13. p=0.008) and kinds of living togather(F=3.69. p=0.003) showed significant differences in the relationship between demographic characteristics and perceived health status. There were no significant differences between demographic characeristics and self-esteem. 3) Monthly allowance(F=3.68. p=0.007). participation in social activity(F=5.90. p=0.000) and number of social activities(F=5.27. p=0.000) showed significant differences in the relationship between socioeconomic characteristics and life satisfaction. Monthly allowance(F=3.13. p=0.01) and number of social activities(F=2.7. p=0.02) showed significant differences in the relationship between socioeconomic characteristics and powerlessness. There were no significant differences between socioeconomic characteristics and perceived health status. Montly allowance(F=4.82. p=0.001). particpation in social activity(F=2.90. p=0.02) and number of social activities(F=3.79. p=0.003) showed significant differences m the relationship between socioeconomic characteristics and self-esteem. 4) Powerlessness showed negative correltionship with perceived health staus(r=-0.295. p<0.001). self-esteem(r=-0.463. p<0.001) and life satisfaction(r=-0.514. p<0.001). Perceived health status showed positive correltionship with self-esteem(r=0.312. p<0.001) and life satisfaction (r=0.377. p<0.001). Self-esteem showed positive correlationship with life satisfaction(r=0.652. p(<0.001). 5) The predicting variances for life satisfaction m elderly people were self-esteem. powerlessness. participation in social activity and perceived health status. The most influencing factor among the variances was the self-esteem$(42.5\%)$ and powerlessness was the second. Both of self-esteem and powerlessness accounted for $48.2\%$ in life satisfaction. The addition of participation of social activity and perceived health status accounted for $52.9\%$ in life satisfaction.

• Bulletin of the Korean Mathematical Society
• /
• v.30 no.1
• /
• pp.61-64
• /
• 1993

In this paper, we show that if R is a local-global domain then the Question holds. McDonald and Waterhouse in [6] and Estes and Guralnick in [5] introduced the concept of local-global rings (so called rings with many units) independently. A local-global ring is a commutative ring R with 1 satisfying; if a polynomial f in R[ $x_{1}$, .., $x_{n}$] represents a unit over $R_{P}$ for every maximal ideal P in R, then f represents a unit over R. Such rings include semilocal rings, or more generally, rings which are von Neumann regular mod their Jacobson radical, and the ring of all algebraic integers.s.s.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.3
• /
• pp.481-485
• /
• 1992

In order to upgrade native sheep, Rambouillet (R) rams were mated to Kaghani (K) ewes to generate F1 ($R{\times}K$) crossbred ewes. Crossbred ewes were backcrossed to Rambouillet rams to produce B1 ($R{\times}F1$), B2 ($R{\times}B1$) and B3 ($R{\times}B2$) genotypes. Weaning weight of 2605 lambs and wool weight of 2378 mature ewe records, representing R, K, F1, B1, B2 and B3 genotypes, were analyzed to compare genetic variation among genotypes produced during upgrading process and identify genotypes of the highest performance. Performance of Rambouillets was also evaluated under semi-temperate climate. Data were adjusted for yearly variation considering Rambouillet as a control. Genotypes influenced lambs weaning weight (p<.01). B1 lambs were heaviest (18.4 kg) followed in order by B2, F1, B3, R and K lambs (18.3, 17.9, 16.9, 16.8 and 13.2 kg, respectively). The highest wool production was 2.5 kg from R ewes followed by B2 (2.3), B3 (2.3), F1 (2.0) and K (1.2) ewes (p < .01). Ewe mating weight, reproduction, growth and wool production of Rambouillets deteriorated significantly after the first decade of their importation. Compared with the first phase (1959-1971), ewe mating weight, litter size, birth weight, lamb weaning weight and wool production declined by 20, 23, 32 and 36%, respectively, in the second phase (1972-1988).

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.38 no.5
• /
• pp.413-417
• /
• 1993

This study was conducted to breed various cytoplasmic genetic male sterile (CGMS) and restorer lines with backgrounds of Korean japonica rice varieties. The CGMS line BT-CMS was crossed with the restorer line AR-3. The fertile $F_1 was emasculated and crossed with the Korean japonica rice varieties of the early maturing Sobaegbyeo, Odaebyeo, Gwanagbyeo and Daeseongbyeo, and of the medium maturing Hwajinbyeo, Paldal, Suwon 224 and Iri 386, and of the late maturing Nagdongbyeo, Palkweng, Hwacheongbyeo and Milyang 97. Each of the three way cross $F_{1S} was segregated into fertile and sterile individuals. The sterile individuals in each cross were discarded and the fertile individuals were emasculated and backcrossed with the Korean japonica rice varieties. The same process was applied from BC$_1$F$_1$ to BC$_4$F$_1$ generation. In the ${BC_4}{F_1}of each cross, the male sterile individual was crossed with the recurrent Korean japonica variety which was maintainer of male sterility. The male sterile lines of ${BC_6}{F_1}were named as Sobaegbyeo R, Odaebyeo R, Gwanagbyeo R, etc. The fertile individuals homozygous in pollen fertility were selected from the ${BC_4}{F_2}generation and named as Sobaegbyeo R, Odaebyeo R, Gwanagbyeo R, etc. Agronomic characteristics of the CGMS, restorer lines with backgrounds of Korean japonica, and the recurrent Korean japonica rice varieties grown in the field condition were compared. Culm length of the CGMS lines tended to be shorter than that of the recurrent parent, however no significant differences in heading date, panicle length and yield component were found among the CGMS, restorer and recurrent lines.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.12
• /
• pp.6353-6363
• /
• 2013

This study examined the factors associated with recurrent falls among the community-dwelling elderly. The participants were 329 community-dwelling elderly. The data was collected from February 5, 2010 to February 14, 2010. Over the past 1 year, 14.3% of the 329 participants fall once, and 4.0% experienced recurrent falls. There was a significant difference among the non fallers, single faller and recurrent fallers with regard to the static balance(F=5.86, p=.003), dynamic balance(F=24.32, p<.001), risk of fall(F=9.94, p<.001) and compliance of prevention behavior related to falls(F=3.09, p=.047). The analysis results for the correlation between variables showed that the number of falls had a negative effect on the knee flexors muscular strength(r=-.15, p=.008), static balance(r=-.16, p=.004) and compliance of prevention behavior related to falls(r=-.12, p=.030) and a positive affect for the dynamic balance(r=.26, p<.001), depression(r=.13, p=.019) and risk of falls(r=.30, p<.001). The variables explained 36.0% of the variants in the occurrence of recurrent falls. Therefore, an effective recurrent fall prevention program should focus on multiple risk factor intervention.

• Animal Bioscience
• /
• v.36 no.10
• /
• pp.1488-1498
• /
• 2023

Objective: α_S1-Casein is more closely associated with milk allergic reaction than other milk protein components. microRNA (miRNA) is a class of small non-coding RNAs that modulate multiple biological progresses by the target gene. However, the post-transcriptional regulation of α_S1-casein expression by miRNA in ruminants remains unclear. This study aims to explore the regulatory roles of miR-380-3p on α_S1-casein synthesis in goat mammary epithelial cells (GMEC). Methods: α_S1-Casein gene and miR-380-3p expression was measured in dairy goat mammary gland by quantitative real-time polymerase chain reaction (qRT-PCR). miR-380-3p overexpression and knockdown were performed by miR-380-3p mimic or inhibitor in GMEC. The effect of miR-380-3p on α_S1-casein synthesis was detected by qRT-PCR, western blot, luciferase and chromatin immunoprecipitation assays in GMEC. Results: Compared with middle-lactation period, α_S1-casein gene expression is increased, while miR-380-3p expression is decreased during peak-lactation of dairy goats. miR-380-3p reduces α_S1-casein abundance by targeting the 3'-untranslated region (3'UTR) of α_S1-casein mRNA in GMEC. miR-380-3p enhances β-casein expression and signal transducer and activator of transcription 5a (STAT5a) activity. Moreover, miR-380-3p promotes β-casein abundance through target gene α_S1-casein, and activates β-casein transcription by enhancing the binding of STAT5 to β-casein gene promoter region. Conclusion: miR-380-3p decreases α_S1-casein expression and increases β-casein expression by targeting α_S1-casein in GMEC, which supplies a novel strategy for reducing milk allergic potential and building up milk quality in ruminants.