• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.589-594
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• 2002

In computer graphics, L-system is primarily used for the production of such natural shapes as flowers, trees, and grass. It is possible by iteratively applying the theory of multiple-reduction-copy-machine to an arbitrary initial shape. The purpose of this paper is to modify the shape of ordinary L-system trees so that more realistic trees can be generated. Instead of applying simple iterative function system of the L-system, we regard each branch of the trees as a living thing, and endow them with corresponding attributes. Such branch attributes as lifetime, growth speed, shape variation, attraction by environment are known to belong to the attributes of the particle system. We presented modeling methods as hypotheses for each of the attributes based on parameters, iud shown the resulting diverse tree shapes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.2
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• pp.269-286
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• 2011

In this paper, we study a problem that is concerning how to construct a delay-constrained multicast tree on a wireless mesh network (WMN) such that the number of serviced clients is maximized. In order to support high-quality and concurrent interference-free transmission streams, multiple radios are implemented in each mesh node in the WMNs. Instead of only orthogonal channels used for the multicast in the previous works, both orthogonal and partially overlapping channels are considered in this study. As a result, the number of links successfully allocated channels can be expected to be much larger than that of the approaches in which only orthogonal channels are considered. The number of serviced subscribers is then increased dramatically. Hence, the goal of this study is to find interference-free and delay-constrained multicast trees that can lead to the maximal number of serviced subscribers. This problem is referred as the MRDCM problem. Two heuristics, load-based greedy algorithm and load-based MCM algorithm, are developed for constructing multicast trees. Furthermore, two load-based channel assignment procedures are provided to allocate interference-free channels to the multicast trees. A set of experiments is designed to do performance, delay and efficiency comparisons for the multicast trees generated by all the approximation algorithms proposed in this study.

• Plant Resources
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• v.7 no.1
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• pp.77-86
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• 2004

The reduced ratio of red:far-red (R:FR) light acts as a measure of the proximity of competitors and plants can detect the potentially competing neighbor plants by perceiving reflected R:FR signals and initiate the response of “shade avoidance” before actual shading occurs. The phytochrome system is responsible for monitoring the changes in the R:FR and initiating the shade avoidance response. The response to low R:FR ratio was studied in a white aspen Populus alba clone ‘Bolleana’ using two filter systems: a clear plastic filter system that allows a R:FR ratio less than 1.0 to pass from adjacent border plant reflection; and a special commercial plastic that blocks FR light and creates a R:FR ratio above 3.0. The reduced R:FR signals enhanced the stem elongation in response to competition at the expense of relative stem diameter growth. Trees grown inside clear chambers were 27 ％ taller than trees grown inside the FR-blocking filter chambers. Stem taper of clear chamber trees was 16％ less than the FR-blocking filter trees. Low R:FR also induced 22％ more stem dry weight and 13％ greater petiole length per leaf compared to the FR-blocking filter trees. There were no statistically significant differences in leaf area, leaf number increment, and total dry weight between the two light filter treatments.

• Journal of Forest and Environmental Science
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• v.34 no.6
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• pp.419-428
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• 2018

Spatial point-patterns analyses were conducted to provide insight into the ecological process behind competition and mortality in two lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands, one in the Lower Foothills, and the other in the Upper Foothills natural subregions in the boreal forest of Alberta, Canada. Spatial statistical tests were applied to live and dead trees and included Clark-Evans nearest neighbor statistic (R), nearest neighbor distribution function (G(r)), and a variant of Ripley's K function (L(r)). In both lodgepole pine plots, the results indicated that there was significant regularity in the spatial point-pattern of the surviving trees which indicates that competition has been a key driver of mortality and forest dynamics in these plots. Dead trees generally showed a clumping pattern in higher density patches. There were also significant bivariate relationships between live and dead trees, but the relationships differed by natural subregion. In the Lower Foothills plot there was significant attraction between live and dead tees which suggests mainly one-sided competition for light. In contrast, in the Upper Foothills plot, there was significant repulsion between live and dead trees which suggests two-sided competition for soil nutrients and soil moisture.

• Journal of Forest and Environmental Science
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• v.37 no.2
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• pp.128-140
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• 2021

Tropical dry forests are one of the most threatened, widely distributed ecosystems in tropics and estimation of forest biomass is a crucial component of global carbon emission estimation. Therefore, the present study was aimed to quantify the biomass and carbon storage in trees on large scale (10, 1 ha plots) in the dry mixed evergreen forest of Javadhu forest of Eastern Ghats. Biomass of adult (≥10 cm DBH) trees was estimated by non-harvest methods. The total biomass of trees in this tropical dry mixed evergreen forest was ranged from 160.02 to 250.8 Mg/ha, with a mean of 202.04±24.64 Mg/ha. Among the 62 tree species enumerated, Memecylon umbellatum accumulated greater biomass and carbon stocks (24.29%) more than the other species in the 10 ha study plots. ANOVA revealed that there existed a significant variation in the total biomass and carbon stock among the three plant types (Evergreen, brevi-deciduous and deciduous (F (2, 17)=15.343, p<0.001). Basal area and density was significant positively correlated with aboveground biomass (R² 0.980; 0.680) while species richness exhibited negative correlation with above ground biomass (R² 0.167). Finding of present study may be interpreted as most of the trees in this forest are yet to be matured and there is a net addition to standing biomass leading to carbon storage.

• Journal of People, Plants, and Environment
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• v.24 no.1
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• pp.85-94
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• 2021

Background and objective: This study examined, compared, and analyzed the tree vitality of the trees growing on the artificial ground of Seoullo 7017 that transformed the overpass that was to be demolished into a "sky garden" using portable tree pots. Methods: Based on the summer season when the metabolic activity of plants is most active, this study measured the cambial electrical resistance in four directions(east, west, south and north), using the Shigometer (model OZ-93, Osmose) and compared the location and analysis of pots according to their means and standard errors. Results: Meanwhile, according to the analysis, vitality was relatively superior in pots with a big diameter, trees planted individually than in groups, trees of the ramp section rather than the bridge section, and in the southwest direction of the cambium. Conclusion: This study revealed the improper condition of the planting plan and implementation on the site, where various species of trees are displayed in a poor environment. Despite the significant assessment of the vitality of various trees introduced within Seoullo 7017 for the first time, this study is limited in that the data used were measured only once in summer. In this regard, it raised the need for continuous interest in and monitoring of a special plant environment and development of proper maintenance and management techniques, along with follow-up research on seasonal and temperature conditions, soil moisture and root development conditions to supplement this research.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.94.1-94
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• 2003

Control of bacterial blossom blight of kiwifruit (Actinidia deliciosa) has been mainly depended on chemical control. Recently cultural practices such as trunk girdling of kiwifruit trees and rainproof installation over kiwifruit trees also were conducted as the alternative control practices. Each of the control methods was evaluated for the best practicing conditions for the control of bacterial blossom blight of kiwifruit. Among the various combinations of spray times and spray periods, optimum spray program of antibiotics was turned out to be 3 times with intervals of 10 days from early May during the flowering season of kiwifruits. Optimum periods of trunk girdling of kiwifruit trees were from late March to late April. Trunk girdling with 20-30 mm wide showed best control efficacies on bacterial blossom blight, irrespective of the heights of girdling on trunks of kiwifruit trees. Optimum period of rainproof installation over kiwifruit trees was from March till late April, irrespective of installation methods.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2092-2098
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• 2024

Probabilistic safety assessment (PSA) plays a critical role in ensuring the safe operation of nuclear power plants. In PSA, event trees are developed to identify accident sequences that could lead to core damage. These event trees are then transformed into a core-damage fault tree, wherein the accident sequences are represented by usual and complemented logic gates representing failed and successful operations of safety systems, respectively. The core damage frequency (CDF) is estimated by calculating the minimal cut sets (MCSs) of the core-damage fault tree. Delete-term approximation (DTA) is commonly employed to approximately solve MCSs representing accident sequence logics from noncoherent core-damage fault trees. However, DTA can lead to an overestimation of CDF, particularly when fault trees contain many nonrare events. To address this issue, the present study introduces a new zero-suppressed ternary decision diagram (ZTDD) algorithm that averts the CDF overestimation caused by DTA. This ZTDD algorithm can optionally calculate MCSs with DTA or prime implicants (PIs) without any approximation from the core-damage fault tree. By calculating PIs, accurate CDF can be calculated. The present study provides a comprehensive explanation of the ZTDD structure, formula of the ZTDD algorithm, ZTDD minimization, probability calculation from ZTDD, strength of the ZTDD algorithm, and ZTDD application results. Results reveal that the ZTDD algorithm is a powerful tool that can quickly and accurately calculate CDF and drastically improve the safety of nuclear power plants.

• Korean Journal of Environment and Ecology
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• v.31 no.4
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• pp.409-419
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• 2017

Although Korean red pine (Pinus densiflora) forests near temples are valuable as forests of the cultural landscape, they are likely to be deteriorated because of vegetation succession and climate changes. The purpose of this study is to investigate the vegetation structure, the pine vitality, and the site environmental characteristics of the pine forests near temples to identify the correlation between pine tree growth and location environment. We selected Chuneunsa, Wonhyosa, Jeungsimsa, and Taeansa Temples since these four areas still had the healthy pine forests. In all four studied area, the pine trees dominate the canopy layers while the deciduous broadleaf trees mostly inhabited appeared in the lower layers. The growth of pine trees in Jeungsimsa and Wonhyosa areas was not as good as Chuneunsa area where the pine trees tended to be older. We found higher total nitrogen content in soil in Jeungsimsa area than other areas, maybe because of increase in total nitrogen caused by the development of low vegetation in the area. This peculiarity may have led to the pine trees in the area to fall behind the deciduous broadleaf trees in competition for nitrogen nutrient and thus to show deteriorated growth. The altitude and the twig length showed a negative correlation as did the degree of slope and the mean importance percentage of the pine tree. In other words, the growth environment such as soil became poorer when the altitude and the degree of slope increased, and thus the growth amount and dominance of the pine trees were lower. The degree of slope showed a positive correlation with the twig length of the pine tree. Within boundaries of location environment where the pine tree forests were dominant, it seemed that growth of the pine trees was more favorable as the slope was steeper because the trees could avoid competition with deciduous broadleaf trees. On the other hand, the growth of pine trees deteriorated as the electrical conductivity of soil increased; increase in soil nutrients might have accelerated vegetation development of deciduous broadleaf trees and thus aggravated the growth environment of pine trees to negatively affect maintaining the health of the pine tree forests.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.155-165
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• 2015

Well-feathered (over 10 feathers) 'Fuji'/M.9 apple trees were planted at $3.0{\times}1.0m$ and trained to slender spindle with 2.5 m height or to tall spindle with 3.5 m height, and the vegetative growth, productivity, and fruit quality of two training systems were compared for 8 years. The canopy volume of the tall spindle trees surpassed that of the slender spindle trees 4 years after planting and was 25% larger than that of the slender spindle trees 5 years after planting. The accumulated yield over 8 years for the tall spindle system was 14% higher than that of the slender spindle system. Alternate bearing and incidence of marssonina blotch were observed in both treatments after 5 years of planting. There was often vegetative imbalance in the trees however, the degree of yield loss and vegetative imbalance of the tall spindle trees was lower than those of the slender spindle trees. Soluble solid content and fruit red color of the tall spindle trees were higher than that of the slender spindle trees in 5 year after planting, resulting from increased light penetration in the canopy due to even distribution of lateral branches and from fruit bearing in different height locations of the trees. In conclusion, increasing the tree height to about 3.5 m using slender spindle 'Fuji'/M.9 apple trees planted with over 333 trees per 10a led to better light penetration, yield and fruit quality compared to a conventional wide training system with the slender spindle.