• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.553-554
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• 2015

This paper presents the selection method of Minimal Cut Sets(MCS) for substation reliability evaluation. We used the Quality solution in order to model the FT for the substation equipment. Quantitative analysis is performed to estimate the probability of top event occurrence and unreliability of the substation component. In this result, it means that reliability indices which can be predict get electricity services and better maintenance in substation management.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.4
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• pp.36-58
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• 1999

We designed the model picture of Tourism Botanical Garden, as a kind of theme park, in which we could enjoy flowers all the year round and the glorious tints of its autumn foliage. It would be very important to decide what kinds of trees should be planted and where to plant them. We selected the appropriate flowers and trees according to their value of appreciation and flowering time and the grand view around there and the weather conditions of the central region. We selected perennial plants as native plants, according to their color, flowering time and for the convenience of maintenance. And we selected some kinds of culture plants to show the seasonal change and diversity, according to their color and flowering time. We adopted the roof-tile pattern of Pakjae Kingdom to design the basic model of the garden, and the area was divided into eight sections. Six of them were divided again into four small planting areas from the outside respectively, according to the kinds of trees; pine-tree area, native flowering plant area, flowering tree area and flowering shrub area. The last two sections are by a lake, so they could make a beautiful landscape of waterfront. For the effective and economic operation of the garden, some kinds of flower trees and shrubs, which are little damaged by blight and are needless to prune, were selected. And perennial plants were also selected, because we don't have to change them into other plants, so we could cut down the expenses. As for the culture plants, they could be easily replaced with other culture plants in the flowering time, to show seasonal change and the harmony with the scenery around the garden.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.303-310
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• 2015

Game technologies are now applied in various engineering areas such as the simulation of surgical operation or the implementation of a cyber model house. One of the essential and important technology in these applications is cutting of the 3D polygon model in real time. Real-time cutting technology is an essential technology needed to implement the simulation of a building demolition or a car assembly for training or educational purpose. Previous cutting method using the conventional BSP-Tree structure has some limitations in that they divide the whole world including the 3D model and its environment, only into two parts with respect to an infinite plane. In this paper, we show a technique cutting the 3D model in a finite extent in order to solve this problem. Specifically, we restricted the cut surface in a finite rectangular area and constructed the mesh for the divided surface. To show the usefulness of our partial cutting technique, an example of the dismantling process simulation of a nuclear reactor polygon model was illustrated.

• The korean journal of orthodontics
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• v.43 no.6
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• pp.279-287
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• 2013

Objective: To investigate the dentoskeletal factors which may predict soft-tissue chin strain during lip closure. Methods: The pretreatment frontal and lateral facial photographs and lateral cephalograms of 209 women (aged 18-30 years) with Angle's Class I or II malocclusion were examined. The subjects were categorized by three examiners into the no-strain and strain groups according to the soft-tissue chin tension or deformation during lip closure. Relationships of the cephalometric measurements with the group classification were analyzed by logistic regression analysis, and a classification and regression tree (CART) model was used to define the predictive variables for the group classification. Results: The lower the value of the overbite depth indicator (ODI) and the higher the values of upper incisor to Nasion-Pogonion (U1-NPog, mm), overjet, and upper incisor to upper lip (U1-upper lip, mm), the more likely was the subject to be classified into the strain group. The CART showed that U1-NPog was the most prominent predictor of soft-tissue chin strain (cut-off value of 14.2 mm), followed by overjet. Conclusions: To minimize strain of the soft-tissue chin, orthodontic treatment should be oriented toward increasing the ODI value while decreasing the U1-NPog, overjet, and U1 upper lip values.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.2
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• pp.1-9
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• 2009

Due to the increase of carbon dioxide in the atmosphere and global warming, the importance of forest ecosystems, as a place of carbon accumulation and emission, has received a great amount of recognition lately. This study was performed to help understand and provide the current status of carbon cycle in the pinus densiflora stand, Korea. The samples were collected from average 35-years-old Pinus densifiora rands in Gongju, Youngdong, Chungsan, Muju, Mupung, and Jangsu regions. Total thirty aboveground sample trees were cut, and ten roots were sampled, and soil samples were collected. Average carbon concentrations in foliage, branch, stem bark, stem wood, and root were 55.7%, 56.0%, 56.0%, 57.3%, and 56.5%, respectively. Carbon content was estimated by the model $Wt=aD^b$ where Wt is oven-dry weight in kg and D is DBH in cm. Total carbon content (aboveground and root) was 42.39tonC/ha in the Pinus densiflora stand. The proportion of each tree component to total carbon content was high in order of stemwood, root, branch, stem bark, and foliage. Total net primary production (aboveground and root) was estimated at 6.51tonC/ha/yr in Pinus densiflora stand. The proportion of each tree component to total net primary carbon content was high in order of sternwood, root, branch, foliage and stembark. Soil carbon contents in the study sites was 43.51tonC/ha at 0-50cm soil depth.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.249-255
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• 2000

This study has been carried out to estimate aboveground biomass and net primary production in a 22-year-old Betula platyphylla and 24-year-old juglans mandshurica plantations. Nine sample trees were cut in each plantation. Estimations for aboveground biomass and net primary production were made by the equation model $Wt=aD^b$ where Wt is ovendry weight in kg and D is DBH in cm. Total aboveground biomass was 79.33t/ha in Betula platyphylla plantation and 67.47t/ha in Juglans mandshurica plantation. The proportion of each tree component to total aboveground biomass was high in order of bolewood, branches, bolebark, and leaves in the two plantations. Aboveground total net primary production was estimated at 9,92t/ha in Betula platyphylla plantation and 11.79t/ha in Juglans mandshurica plantation. There was greater net primary production in Juglans mandshurica plantation than in Betula platyphylla plantation because of greater bolewood, bolebark, current twig, and branch net primary productions in Juglans mandshurica plantation than in Betula platyphylla plantation.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.6
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• pp.17-25
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• 2018

This study was conducted to calculate the optimum height of trees, estimating a model for the prediction of tree growth for the landscape improvement of the Gyeonghoeru area. For the verification of measures for management, this study conducted a photographic survey of the Gyeonghoeru area and used the Pressler's formula to examine the growth rate of the pine forest of Mansesan. The results of the study are as follows. First, as a result of a field survey and landscape analysis, trees in the Gyeonghoeru area are large ones with more than a diameter at breast height of 30cm, except for weeping cherry trees and persimmon trees, and especially, it is necessary to manage them or replace with small trees through the landscape of Mansesan, which screens the landscape and pruning the trees in the terraced flower garden in the north. Second, as a result of a measurement of the growth rate of trees, for 10 years on average, they grew up by 14% in source diameter and 5% in tree height 5% in south of Mansesan and by 7% in source diameter and 2.4% in tree height in the north of Mansesan. Furthermore, when a simulation was prepared based on the measured growth rate of trees, it was found out that 20 years later, on the landscape on the second floor of Gyeonghoeru, the pine forest of Mansesan would cut off the skyline of Mt. Inwang-san. Third, this study analyzed a landscape improvement simulation and proposed a plan for tree management to take a view of the landscape of the Gyeonghoeru area. This study has a significance that it drew an efficient planting maintenance policy, considering the landscape characteristics of the Gyeonghoeru area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.25-31
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• 2014

Korean grammar checkers typically detect context-dependent errors by employing heuristic rules; these rules are formulated by language experts and consisted of lexical items. Such grammar checkers, unfortunately, show low recall which is detection ratio of errors in the document. In order to resolve this shortcoming, a new error-decision rule-generalization method that utilizes the existing KorLex thesaurus, the Korean version of Princeton WordNet, is proposed. The method extracts noun classes from KorLex and generalizes error-decision rules from them using the Tree Cut Model and information-theory-based MDL (minimum description length).

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.17-24
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• 2006

We consider the sensor location problem (SLP) on a given sensor field. We present the sensor field as grid of points. There are several types of sensors which have different detection ranges and costs. If a sensor is placed in some point, the points inside of its detection range can be covered. The coverage ratio decreases with distance. The problem we consider in this thesis is called multiple-type differential coverage sensor location problem (MDSLP). MDSLP is more realistic than SLP. The coverage quantities of points are different with their distance form sensor location in MDSLP. The objective of MDSLP is to minimize total sensor costs while covering every sensor field. This problem is known as NP-hard. We propose a new integer programming formulation of the problem. In comparison with the previous models, the new model has a smaller number of constraints and variables. This problem has symmetric structure in its solutions. This group is used for pruning in the branch-and-bound tree. We solved this problem by branch-and-cut(B&C) approach. We tested our algorithm on about 60 instances with varying sizes.

• Journal of Korean Dental Science
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• v.16 no.1
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• pp.47-62
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• 2023

Purpose: We aimed to investigate the objective cutoff values of unstimulated flow rates (UFR) and stimulated salivary flow rates (SFR) in patients with xerostomia and to present an optimal machine learning model with a classification and regression tree (CART) for all ages. Materials and Methods: A total of 829 patients with oral diseases were enrolled (591 females; mean age, 59.29±16.40 years; 8~95 years old), 199 patients with xerostomia and 630 patients without xerostomia. Salivary and clinical characteristics were collected and analyzed. Result: Patients with xerostomia had significantly lower levels of UFR (0.29±0.22 vs. 0.41±0.24 ml/min) and SFR (1.12±0.55 vs. 1.39±0.94 ml/min) (P<0.001), respectively, compared to those with non-xerostomia. The presence of xerostomia had a significantly negative correlation with UFR (r=-0.603, P=0.002) and SFR (r=-0.301, P=0.017). In the diagnosis of xerostomia based on the CART algorithm, the presence of stomatitis, candidiasis, halitosis, psychiatric disorder, and hyperlipidemia were significant predictors for xerostomia, and the cutoff ranges for xerostomia for UFR and SFR were 0.03~0.18 ml/min and 0.85~1.6 ml/min, respectively. Conclusion: Xerostomia was correlated with decreases in UFR and SFR, and their cutoff values varied depending on the patient's underlying oral and systemic conditions.