• Journal of Korean Society of Forest Science
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• v.90 no.6
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• pp.717-724
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• 2001

This study was conducted in an attempt to quantify some traits that may be involved in the reproductive process of Pinus thunbergii. During the past 6 years (1995-2000), we surveyed flowering patterns of 60 P. thunbergii clones in a seed orchard which was established in Anmyon-do, 1979. From this survey, we estimated clonal contributions of male and female flowers and sexual asymmetry. Among 60 clones, 18 clones (30%) accounted for 0.37 (1999)~0.46 (1995) of clonal contribution in female flowers and 0.44 (1999)~0.57 (1995) of clonal contribution in male flowers. As compared with the previous reports in other pine species, more clones made contributions to reproductive process in P. thunbergii seed orchard. The relative effective population numbers for females (v♀) varied from 0.59 (1995) to 0.91 (1999) and those for males ( v♂) were between 0.56 (1995) and 0.83 (1998) at gamete level. This showed that the female gametes effectively contribute to the reproductive process more than did the male gametes. The relative effective population numbers at clonal level ($v_b$) were in the range of 0.72 (1995) and 0.93 (1999). More than 73% of the total clones showed values of 0.4~0.6 ($0.5{\pm}0.1$) in maleness index. The values averaged over all the clones were temporally variable with the range of 73% in 1996 and 100% in 2000. The degree of sexual asymmetry ($A_s$) ranged from 0.09 to 0.26. These values were relatively low when compared with those of other trees, suggesting that P. thunbergii seed orchard remains a high level of homogeneity in the number of male and female. All of the various types of effective population numbers were positively correlated with each other while they were negatively correlated with the degree of sexual asymmetry.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.201-212
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• 2021

In wetland protection areas, a phytosociological research was conducted on willow forests, which plays an important ecological and environmental role and is the main material for ecological restoration. A total of 61 relevés were collected according to the Z-M(Zürich-Montpellier) school's method and the characteristics of plant communities and the composition of the species were identified. A total of 9 plant communities including 237 taxa were differentiated. Willow species showing the high r-NCD(relative net contribution degree) value in study areas were Salix koriyanagi, Salix chaenomeloides, Salix triandra subsp. nipponica, Salix gracilistyla and Salix pierotii. Poaceae was the most diverse in species, followed by Asteraceae, Apiaceae, Polygonaceae and Fabaceae. Life form type of willow forests in wetland protection areas was determined to be Th(therophytes)-R₅(non-clonal form)-D₄(clitochores)-e(erect form) type. The naturalized plants and invasive alien species were identified as 24 taxa and 4 taxa, respectively. Naturalized and disturbance indices were 10.1% and 41.4%, respectively. The results of the site-species ordination by Non-Metric Multidimensional Scaling(NMDS), wetland types and altitude gradient were the main ecological factors determining the spatial distribution of plant communities. Diversity index and evenness index were high in mountainous palustrine wetlands with relatively high altitude, and the disturbance index, naturalized index and appearance rate of annual plant were high in riverine and lacustrine wetlands with low altitude.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.245-252
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• 2009

The grassland establishment under the forest become important, but it comes with a shade for the grass growing among trees. The objective of this study is to select the proper grass-clover mixtures to several shading degrees. The grass-clover mixtures were grown under full sunlights and shade cloths, which reduce sunlight intensity by 35, 50 and 75%. The various types of mixtures were allocated at each shading degrees with three replications. The productivity of mixtures was the highest under full sunlights, and intermediate with 35% degree of shading and least with both 50 and 75% degrees of shading. The 1st mixture (orchardgrass+tall fescue+Kentucky bluegrass+ladino clover+perennial ryegrass+timothy) showed the greatest yield in all treatments. The crude protein (CP) concentration of all mixtures increased with the higher degree of shading, but no CP concentration difference was observed in mixtures within same degree of shading. The lowest neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations and highest relative feed value (RFV) were resulted in the 1st mixture in all treatments. This study indicates that tall fescue, Kentucky bluegrass, ladino clover, perennial ryegrass and timothy can be used as components for mixtures with orchardgrass which is major component for forest-pastures.

• Research in Plant Disease
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• v.15 no.3
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• pp.193-197
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• 2009

Pseudocercospora leaf spot was major disease of grape cultivar 'Campbell Early' in Korea. Leaf spot first appeared in early June and rapidly dispersed to other leaves through rainy season. Disease progress of leaf spot by Pseudocercospora vitis in plastic green house, in the two provinces (Gimje and Gimcheon), were investigated in 2007. Differences of Infected leaves (%) between cultivation systems were observed in field and plastic green house, but there was no difference between provinces. Micro environmental factors, such as temperature and relative humidity, were correlated with infected leaves by PROC REG procedure of SAS (Statistical Analysis System). As a result, regression model best described ($R^2=0.95^{**}$) the infected leaves as a function of the interaction of cumulated temperatures; Y (Infected leaves)=-7.0101+0.0496$\times$20Hcum (Cumulated hour above 20 degree)+0.0208$\times$20cum (Cumulated temperature above 20 degree)-0.2781$\times$25Hcum (Cumulated hour above 25 degree). A statistics model was shown that cumulated hour and temperature above specific degree were critical factor for Pseudocercospora leaf spot on the grapevine leaves in plastic green house.

• Journal of Environmental Impact Assessment
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• v.23 no.4
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• pp.315-322
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• 2014

After the modern industrial revolution, rivers in cities became covered and disappeared due to the pressure to develop them. Likewise, their function which is to serve as the basis of natural ecology system in the cities began to be damaged. This research demonstrated that there are a total of 268 categories when it comes to the list of plants, including 64 families, 179 genera, 230 species, 36 varieties, and 1 subspecies. When the relative abundance of the plants that were found at the target research site was studied, the secondary survey demonstrated Bromus japonicus 22.97, Artemisia princeps var. orientalis 16.76 and Erigeron annuus 15.69 while third survey demonstrated Digitaria ciliaris 26.78, Ambrosia trifida 16.29 and Aster pilosus 14.31. There were 54 species of naturalized plants that appeared. Analysis demonstrated annual plant 23 classification category (43%), perennial 11 classification category (20%), multi-perennation 17 classification category (31%), woody plant 3 classification category (6%) and others. When the naturalized plants that were found at the target research site were analyzed by the place of origin, North America and EU took up 76%, which accounts for 3/4 of the all the naturalized plants. At the target research site, naturalization degree of 5 pertained to 22 classification category (41%), which was the highest, followed by 19 classification category (35%) with naturalization degree of 3, 8 classification category (15%) with naturalization degree of 2 and 5 classification category (9%) with naturalization degree of 4 in the order mentioned. Flora of Jungnangcheon did not manifest any change compared to 10 years ago. Thus, it is necessary to increase of biodiversity efforts to improve SeoulCity's natural environment and cityscape.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.7
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• pp.63-73
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• 2015

In the end to end data transfer protocols, it is very important to correctly estimate available bandwidth. In UDT (UDP based Data Transfer), receiver estimates the MTR (Maximum Transfer Rate) of the current link using pair packets transmitted periodically from sender and, then sender finally decides the MTR through EWMA (Exponential Weighted Moving Average) algorithm. Here, MTR has to be exactly estimated because available bandwidth is calculated with difference of MTR and current transfer rate. However, when network is congested due to traffic load and where competing flows are coexisted, it bring about a severe fairness problem. This paper proposes a congestion degree based MTR estimation algorithm. Here, the congestion degree stands a relative index for current congestion status on bottleneck link, which is calculated with arriving intervals of a pair packets. The algorithm try to more classify depending on the congestion degree to estimate more actual available bandwidth. With the network simulation results, our proposed method showed that the fairness problem among the competing flows is significantly resolved in comparison with that of UDT.

• Journal of agricultural medicine and community health
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• v.32 no.2
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• pp.63-73
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• 2007

Objectives: The purpose of this study was to obtain basal information to establish a proper birth-encouraging policy in the future through the survey of the attitude towards childbirth and its related factors among female students in junior, senior high school, and university. Methods: A survey was performed for 2 weeks in June, 2006, for a total of 688 female students which included 185 ones in a girls' junior high school and 242 ones in a girls' senior high school in Sacheon, and 261 ones in two universities in Jinju. The selfadministered questionnaires developed by the authors included the socio-demographic characteristics, the attitude towards childbirth, the preference of a son for their future child, the belief on relative importance of family or work after marriage, the seriousness perception of low birth rate in Korea, frequencies of education in school about low birth rate. The attitude was measured by an answer to the question of 'To what degree do you think you are going to have a child(or children)?' Results: The proportion of positive attitude towards their future childbirth was 76.2% in junior high school, 63.9% in high school, and 82.8% in university students (p<0.01). In the logistic regression analysis, the significant factors related with positive attitude towards future childbirth were school grade, preference of a son for their future children, and belief on relative importance of family or work after marriage. Conclusions: It suggests that the related factors with positive attitude towards future childbirth need to be considered to make a proper birth policy.

• Journal of Environmental Science International
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• v.9 no.4
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• pp.285-294
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• 2000

Butyltin compounds (BTs) in seawater, sediments and organisms (Thais clavigera, Liolophura japonica and Cellana nigrolineata), were quantitatively determined to evaluate their distribution inside Songsan Harbor of Cheju Island. In addition, imposex in T. clavigera was used to assess the effect on organisms of BTs. Analysis of the samples collected in seawater, sediments (March, June and August) and organisms (May, July and August) in 1998, confirmed the contamination of BTs in the aquatic environment inside Songsan Harbor. The main BTs species in seawater and sediments was monobutyltin (MBT), tributyltin (TBT), respectively, irrespective of survey time. In oranisms, TBT and dibutyltin (DBT) were detected in similar concentrations for T. clavigera and L. japonica, but for C nigrolineata, DBt concentration was the highest. TBT, the most toxic to aquatic organisms among BTs, was found at concentrations which were sufficient to have a serious effect on the sensitive organisms upon chronic exposure, The relatively high correlations (r>0.83) between BTs indicated that DBT and MBT were mainly degraded from TBT based on antifouling paint and their sources were negligible. The sedimentary organic matters did not have influence on the distribution of BTs in marine environment, and lipid content in T. clavigera did not show a correlation with TBT concentrations. The rate of occurrence of imposex in T. clavigera was 100%, and the relative penis length index (RPLI) and the relative penis size index (RPSI) which represent the degree of imposex were 79.7%, 58.1%, respectively. Measurement of imposex in T. clavigera was expected to be a very helpful tool for preliminary survey of BTs prior to trace analysis of BTs.

• Management & Information Systems Review
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• v.17
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• pp.161-189
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• 2005

As the importance of intellectual assets has been brought into relief, this study aims at positively verifying where the intellectual workers' overall level of their knowledge conversion preference and their job character has reached, and how much the knowledge conversion preference, the job character and the fitness of both factors affects the job effectiveness respectively. For this purpose 3 types of research hypotheses were set up and the result of the verification of the hypotheses is summarized as follows: First, the verification of the relation between the knowledge conversion preference and the job effectiveness revealed that the workers who have the higher synthetic ability in knowledge conversion preference show the higher job satisfaction and job product. Secondly, the verification of the relation between the MPS representing the job character by measured index and the job satisfaction revealed that the absolute value of relative coefficient between the 4 factors excluding the public welfare factor and the MPS is 4, interpreted as medium correlation. Thirdly, the analysis on the degree of relation between the job product measured by the quality of job result and the input effort and the MPS showed that the absolute value of person relative coefficient is 5, interpreted not only as medium correlation but also very meaningful. Accordingly, the main purpose of this study was to give a guideline which can be utilized as an indicator for educating, training and placing the workers. As results, the main effect that the variable of knowledge conversion preference and job character chosen as the independent variable influences on the dependent variable of job satisfaction and job product is very meaningful except the public welfare factor.

• Investigative Magnetic Resonance Imaging
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• v.21 no.3
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• pp.131-138
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• 2017

Purpose: To optimize the timing of scans using cardiac magnetic resonance contrast-enhanced timing robust angiography (CMR-CENTRA) for electroanatomic mapping (EAM) of the right atrium (RA) and left atrium (LA) in patients with atrial fibrillation (AF). Materials and Methods: Fifty patients with AF (38 men; mean age, $59.6{\pm}9.3years$) underwent CMR-CENTRA in preparation for EAM. The CMR-CENTRA data were acquired at five different scan times: 0 seconds, 5 seconds, 10 seconds, 15 seconds, and 20 seconds after an intravenous injection of contrast media. To evaluate the degree of contrast enhancement, right atrial relative contrast (RA-RC) and left atrial relative contrast (LA-RC) on the CMR-CENTRA scans were assessed at each time point. The three-dimensional (3D) reconstruction of the RA and LA for the EAM system was performed using the CMR-CENTRA data. Results: A CMR-CENTRA at a scan time of 10 seconds showed significantly greater LA-RC (P < 0.05) compared with all other scan times. A CMR-CENTRA at a scan time of 15 seconds showed significantly greater RA-RC (P < 0.05) compared with all other scan times. In the 3D reconstruction of the RA, the success rates of CMR-CENTRA at scan times of 10 seconds and 15 seconds were 18% and 100%, respectively. In the 3D reconstruction of the LA, the success rates of CMR-CENTRA at 10- and 15-second scan times were 100%. Conclusion: The CMR-CENTRA data acquired at 15 seconds after the injection of contrast media is appropriate for the preparation of an EAM system that is focused on the RA and LA in patients with AF.