• Journal of Wetlands Research
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• v.21 no.4
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• pp.298-304
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• 2019

In this paper, the analytical method to derive wind fragility for urban street tree in Korea was shown. Monte Carlo Simulation method was used to determine the probability of failure for urban street tree. This probability result was used to determine wind fragility parameters for four types of tree based on the study of street tree species in urban area in Daegu, Korea. Wind fragility for street tree was presented in terms of median capacity and standard deviation of the natural logarithm of the capacity. Results showed that the dominant factor affecting the probability of failure of tree under wind load was their diameter. Moreover, amongst the four types of tree chosen, the tree with height 7m and diameter 35cm had the lowest probability of failure under wind loading, whereas the tree with height 8m and diameter 30cm could resist the least wind loading. The median failure wind speed for urban street tree with height 7m were 43.8m/s and 50.6m/s for diameter 30cm and 35cm, respectively. Also, for tree with height 8m, their median failure wind speeds were 38.7m/s and 45.4m/s for tree with diameter 30cm and 35cm, respectively.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.223-230
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• 2003

Feature-based similarity retrieval has become an important research issue in multimedia database systems. The features of multimedia data are useful for discriminating between multimedia objects (e 'g', documents, images, video, music score, etc.). For example, images are represented by their color histograms, texture vectors, and shape descriptors, and are usually high-dimensional data. The performance of conventional multidimensional data structures(e'g', R- Tree family, K-D-B tree, grid file, TV-tree) tends to deteriorate as the number of dimensions of feature vectors increases. The R＊-tree is the most successful variant of the R-tree. In this paper, we propose a SOM-based R＊-tree as a new indexing method for high-dimensional feature vectors.The SOM-based R＊-tree combines SOM and R＊-tree to achieve search performance more scalable to high dimensionalities. Self-Organizing Maps (SOMs) provide mapping from high-dimensional feature vectors onto a two dimensional space. The mapping preserves the topology of the feature vectors. The map is called a topological of the feature map, and preserves the mutual relationship (similarity) in the feature spaces of input data, clustering mutually similar feature vectors in neighboring nodes. Each node of the topological feature map holds a codebook vector. A best-matching-image-list. (BMIL) holds similar images that are closest to each codebook vector. In a topological feature map, there are empty nodes in which no image is classified. When we build an R＊-tree, we use codebook vectors of topological feature map which eliminates the empty nodes that cause unnecessary disk access and degrade retrieval performance. We experimentally compare the retrieval time cost of a SOM-based R＊-tree with that of an SOM and an R＊-tree using color feature vectors extracted from 40, 000 images. The result show that the SOM-based R＊-tree outperforms both the SOM and R＊-tree due to the reduction of the number of nodes required to build R＊-tree and retrieval time cost.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.648-655
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• 2012

This research is aimed at suggesting the reasonable guideline for managing tree density of a therapeutic forest to enhance the therapeutic efficiency. To obtain visually preferable tree density for 4 coniferous tree species; Pinus koraiensis, Chamaecyparis obtusa, Pinus densiflora, Larix kaempferi, the simulations of tree density according to the 3 diameter classes are used. 250 people participated in questionnaire and 239 people of them were analyzed. The tree density preferences of 4 tree species are as follows; Pinus koraiensis forest; tree density for trees with Diameter (DBH=D)<25 cm about 816/ha, tree density for trees with 25=D<40 about 400/ha and tree density for trees with 40=D about 277/ha. Chamaecyparis obtusa forest; tree density for trees with D<25 about 625/ha, tree density for trees with 25=D<40 about 625/ha and tree density for trees with 40=D about 400/ha. Pinus densiflora forest; tree density for trees with D<25 about 816/ha, tree density for trees with 25=D<40 about 625/ha and tree density for trees with 40=D about 400/ha. Larix kaempferi forest; tree density for trees with D<25 about 625/ha, tree density for trees with 25=D<40 about 625/ha and tree density for trees with 40=D about 277/ha.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.372-381
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• 2019

This study was conducted to find proof for the hypothesis that the God tree of Chosun has been misrepresented in Chosun-Gersu-Nosu-Myungmokji (CGNM). The following results were obtained. First, it was established that 64 species and 3170 trees were recorded in CGNM. An old, big tree is classified as a God tree if linked to it there are testimonies and legends about divine elements, and it is classified as a Noble tree if linked to it there are testimonies and legends of historical elements. In total, 2632 trees of eight species were analyzed, from the Zelkova serrata, which has the greatest number of trees, to the eighth most frequent, Abies holophylla. The means of diameter at breast height (DBH), height, and age of the God and the Noble trees were calculated for each of the eight species. In seven out of eight species, the DBH and age of the Noble tree were more than those of the God tree. In addition, the height of the Noble tree was more than that of the God tree in six out of eight species. The fact that the God tree is smaller than the Noble tree, contrary to the common expectation that the Noble tree is a small size tree, was confirmed. This hypothesis was proved by the data gathered. Second, the Japanese Government-General of Korea has pursued a policy to defeat the village ritual based on the God tree being linked with superstition. For such a policy, the God tree should be small and unattractive, and it would have been good for the tree to be superstitious. The CGNM was created as explanatory material or evidence for distorting the sacredness of the God tree of Chosun. Third, CGNM compiled a chronological order of DBH data to make it easy to explain the fabricated facts that the God tree of Chosun is smaller and dwarfed compared to the Noble tree.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.639-649
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• 2011

The purpose of this study aimed to analyze factors on motives to tree burial and choice conditions to tree burial site in order to suggest policy direction for the desirable settlement of tree burial. For those purpose, this study performed questionnaire, targeting 522 visitors of funeral hall all around Korea. As the result, the factors of motives to tree burial were extracted as follows: funeral ceremony progressed along with trees, simplicity, memorial site's easy insurance, environmental friendliness and consideration toward descendants. The factors on choice conditions to tree burial sites were extracted as follows: beauty of natural scenery, emotional mood as a memorial site, convenience, stability and economic feasibility. Based on the results of factor analysis, this study suggested policies related to motives to tree burial as follows: develop various types of tree burial sites, develop a funeral ceremony suitable for tree burial, come into wide use of tree burial as a social welfare service, develop tree burial methods capable of many burials, and improve professionalism to manage tree burial system. In addition, this study proposed related choice conditions to tree burial sites as follows: establish natural forest scenery, convert existing graveyards into tree burial sites, select easily accessible places for tree burial sites, form tree burial sites as places for both rest and memory, and reduce using fee of tree burial site.

• Proceedings of the Korean Reliability Society Conference
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• 2001.06a
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• pp.257-263
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• 2001

In the analysis of product reliability, the fault tree is widely used since it shows the interrelations of the faults that lead to the product fault. A top-down approach based on experts’ experience is commonly used in the fault tree construction and the trees often take different forms depending on the intent of the analyst. In this work it is studied how to construct fault trees with the utilization of function trees obtained from analyzing the functions and sub-functions of products in order to suggest a generic way of fault tree construction. The function tree of a product is obtained by analyzing basic functions comprising the product main function in a bottom-up approach so that it enables to construct an objective fault tree. The fault tree for a scroll compressor is shown as an example.

• Industrial Engineering and Management Systems
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• v.12 no.1
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• pp.9-15
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• 2013

An inverse minimum spanning tree problem makes the least modification on the edge weights such that a predetermined spanning tree is a minimum spanning tree with respect to the new edge weights. In this paper, the concept of uncertain ${\alpha}$-minimum spanning tree is initiated for minimum spanning tree problem with uncertain edge weights. Using different decision criteria, two uncertain programming models are presented to formulate a specific inverse minimum spanning tree problem with uncertain edge weights involving a sum-type model and a minimax-type model. By means of the operational law of independent uncertain variables, the two uncertain programming models are transformed to their equivalent deterministic models which can be solved by classic optimization methods. Finally, some numerical examples on a traffic network reconstruction problem are put forward to illustrate the effectiveness of the proposed models.

• Journal of Information Technology Applications and Management
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• v.13 no.4
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• pp.257-271
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• 2006

Recently, flash memories are one of best media to support portable computer's storages in mobile computing environment. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However, we need to improve traditional Indexing scheme such as B-Tree due to the relatively slow characteristics of flash operation as compared to RAM memory. In order to achieve this goal, we devise a new indexing scheme called F-Tree. F-Tree improves tree operation performance by compressing pointers and keys in tree nodes and rewriting the nodes without a slow erase operation in node insert/delete processes. Based on the results of the performance evaluation, we conclude that F-Tree indexing scheme outperforms the traditional indexing scheme.

• Industrial Engineering and Management Systems
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• v.4 no.1
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• pp.102-108
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• 2005

This paper studies medical data classification methods, comparing decision tree and system reconstruction analysis as applied to heart disease medical data mining. The data we study is collected from patients with coronary heart disease. It has 1,723 records of 71 attributes each. We use the system-reconstruction method to weight it. We use decision tree algorithms, such as induction of decision trees (ID3), classification and regression tree (C4.5), classification and regression tree (CART), Chi-square automatic interaction detector (CHAID), and exhausted CHAID. We use the results to compare the correction rate, leaf number, and tree depth of different decision-tree algorithms. According to the experiments, we know that weighted data can improve the correction rate of coronary heart disease data but has little effect on the tree depth and leaf number.

• Communications for Statistical Applications and Methods
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• v.11 no.3
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• pp.539-551
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• 2004

Multiple responses are often observed in many application fields, such as customer's time-of-day pattern for using internet. Some decision trees for multiple responses have been constructed by many researchers. However, if the response is a high-dimensional vector that can be thought of as a discretized function, then fitting a multivariate decision tree may be unsuccessful. Yu and Lambert (1999) suggested spline tree and principal component tree to analyze high dimensional response vector by using dimension reduction techniques. In this paper, we shall propose factor tree which would be more interpretable and competitive. Furthermore, using Korean internet company data, we will analyze time-of-day patterns for internet user.