• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.161-169
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• 2012

In general, Euclidean minimum spanning tree is a tree connecting input nodes with minimum connecting cost. But the tree may not be optimal when applied to real world problems of three dimension. In this paper, three dimension Euclidean minimum spanning tree is proposed, connecting all input nodes of 3-dimensional space with minimum cost. In experiments for 30,000 input nodes with 100% space ratio, the tree produced by the proposed method can reduce 90.0% connection cost tree, compared with the tree by two dimension Prim's minimum spanning tree. In two dimension plane, the proposed tree increases 251.2% connecting cost, which is pointless in 3-dimensional real world. Therefore, the proposed method can work well for many connecting problems in real world space of three dimensions.

• Journal of the Korea Society of Computer and Information
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• v.17 no.7
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• pp.87-95
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• 2012

In this paper, PTAS three-dimensional Steiner minimum tree connecting numerous input nodes rapidly in 3D space is proposed. Steiner minimum tree problem belongs to NP problem domain, and when properly devised heuristic introduces, it is generally superior to other algorithms as minimum spanning tree affiliated with P problem domain. But when the number of input nodes is very large, the problem requires excessive execution time. In this paper, a method using PTAS is proposed to solve the difficulty. In experiments for 70,000 input nodes in 3D space, the tree produced by the proposed 8 space partitioned PTAS method reduced 86.88% execution time, compared with the tree by naive 3D steiner minimum tree method, though increased 0.81% tree length. This affirms the proposed method can work well for applications that many nodes of three dimensions are need to connect swifty, enduring slight increase of tree length.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.55-62
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• 2004

This paper proposes and analyzes two anti-collision algorithms in Ubiquitous ID system. We mathematically compares the performance of the proposed algorithms with that of binary search algorithm slotted binary tree algorithm using time slot, and bit-by-bit binary tree algorithm proposed by Auto-ID center. We also validated analytic results using OPNET simulation. Based on analytic result comparing the proposed Modified bit-by-bit binary tree algorithm with bit-by-bit binary tree algorithm which is the best of existing algorithms, the performance of Modified bit-by-bit binary tree algorithm is about 5% higher when the number of tags is 20, and 100% higher when the number of tags is 200. Furthermore, the performance of proposed Enhanced bit-by-bit binary tree algorithm is about 335％ and 145% higher than Modified bit-by-bit binary tree algorithm for 20 and 200 tags respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.341-345
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• 2010

WMN is one of efficient solutions to provide Internet services for users by forming wireless backbone networks with wireless links. The dominant technology for WMNs is the IEEE 802.11, which provides multi-channel and multi-rate capabilities. One of important issues in WMNs is the network capacity and it is essential to design a multi-channel protocol that leverages the network capacity. However, when wireless links that use different data rates operate on the common channel, the performance of high-rate links is severely degraded by the presence of the low-rate links, which is often referred as performance anomaly. In this paper, we propose a Tree-based Channel Assignment (TreeCA) protocol to mitigate the performance anomaly problem by distributing data rates over multiple channels. TreeCA performs channel assignments based on the tree WMN architecture to accommodate the Internet traffics efficiently. Parent nodes on the tree distribute their child nodes over multiple channels so that the performance anomaly is reduced. Through simulations, we observed that the proposed TreeCA outperforms the existing multi-channel protocols for WMNs.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.10
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• pp.1228-1241
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• 2011

This research compares the change in berberine content in liquid dye and the color and dye uptake of amur cork tree dyed silk upon thermal degradation treatment. Thermal degradation of amur cork tree extract and liquid dye of standard berberine was carried out at room temperature, $4^{\circ}C$ refrigeration, and $100^{\circ}C$ oven conditions for 0-192 hours. Amur cork tree dyed silk was treated in a $100^{\circ}C$ oven for 0-240 hours. The berberine content in liquid dye was measured by the relative abundance of the berberine peak in the HPLC-MS chromatograms. The color and dye uptake of dyed silk was measured using K/S value and colorimetric data. The berberine content in standard berberine dye was 2.4 times that of the amur cork tree extract. A similar result was observed between the K/S value of standard berberine dyed silk and that of amur cork tree dyed silk. The berberine dyed silk showed the highest dye uptake after 120 hours in a $100^{\circ}C$ oven. This result was similar to the change in a berberine content in liquid dye in a $100^{\circ}C$ oven treatment. The change of the K/S value of amur cork tree dyed silk and berberine content of amur cork tree extract was similar up to 24 hours. The result suggests that there is a direct relationship between the color change of amur cork tree dyed silk and the berberine content in amur cork tree dye.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.63-71
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• 2011

Cardiac disorder data are generally tested using the classifier and QRS-Complex and R-R interval which is used in this experiment are often extracted by ECG(Electrocardiogram) signals. The experimentation of ECG data with classifier is generally performed with SVM(Support Vector Machine) and MLP(Multilayer Perceptron) classifier, but this study experimented with Best-First Decision Tree(B-F Tree) derived from the Dicision Tree among Random Forest classifier algorithms to improve accuracy. To compare and analyze accuracy, experimentation of SVM, MLP, RBF(Radial Basic Function) Network and Decision Tree classifiers are performed and also compared the result of announced papers carried out under same interval and data. Comparing the accuracy of Random Forest classifier with above four ones, Random Forest is the best in accuracy. As though R-R interval was extracted using Band-pass filter in pre-processing of this experiment, in future, more filter study is needed to extract accurate interval.

• Journal of KIISE:Databases
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• v.31 no.2
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• pp.150-162
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• 2004

Moving objects have characteristics that they change continuously their positions over time. The movement of moving objects should be stored on trajectories for processing past queries. Moving objects databases need to provide spatio-temporal index for handling moving objects queries like combined queries. Combined queries consist of a range query selecting trajectories within a specific range and a trajectory query extracting to parts of the whole trajectory. Access methods showing good performance in range queries have a shortcoming that the cost of processing trajectory Queries is high. On the other hand, trajectory-based index schemes like the TB-tree are not suitable for range queries because of high overlaps between index nodes. This paper proposes new TR(Trajectory Riving)-tree which is revised for efficiently processing the combined queries. This index scheme has several features like the trajectory preservation, the increase of the capacity of leaf nodes, and the logical trajectory riving in order to reduce dead space and high overlap between bounding boxes of nodes. In our Performance study, the number of node access for combined queries in TR-tree is about 25% less than the STR-tree and the TB-tree.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.415-421
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• 2016

A behavior tree is to express the behavior of artificial intelligence. The behavior tree has a characteristic that is easy to change state transitions than FSM(Finite State Machine), see the progress of the action. For these reasons, the behavior tree is widely used in more than FSM. This paper is to analyze the advantages and disadvantages on behavior trees of game engines, proposes the improved behavior tree based on analyzed them. To achieve this, in this paper, first, examines the role of node and the behavior tree structure of the unity engine, unreal engine. Second, discusses the advantages and disadvantages based on it. Third, proposes the behavior tree to improve the disadvantages of behavior tree of unity engine and unreal engine, depth of behavior tree and search time required to select the execution node. This paper can help developers using the tree to develop the game.

• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.90-100
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• 2019

This study aims to determine the ideal feed speed of a resistograph to evaluate the number of tree rings in several tree species. The needle speed was fixed at 1,500 r/min. Herein, various tree species, such as Pseudotsuga menziesii, Pinus koraiensis, Abies holophylla, and Zelkova serrata, were considered for experiments. Results showed that the most proper feed speed for Zelkova serrata, Larix kaempferi, Pseudotsuga menziesii, Abies holophylla, and Pinus koraiensis was 75, 100, 100, 150, and 175 cm/min, respectively. However, in all the cases, the electric resistance values of tree ring narrower than 1 mm were not suitable for determining tree-ring boundaries. Upon comparing the inter-annual time series of ring widths and electric resistance values of resistograph, a meaningful synchronization was verified. If resistograph would be improved to the extent that it can measure tree rings narrower than 1 mm, it can replace the conventional method used for counting the number of tree rings in the increment cores. Additionally, it can also be used to investigate the tree growth.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.2
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• pp.1-12
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• 2019

Open space planners and designers should consider scientific and quantified functions of trees when they have to locate where to plant the tree. However, until now, most planners and designers could not consider them because of lack of tool for considering scientific and quantitative tree functions. This study introduces a tree location supporting tool which focuses on the multi-objective including scientific function using ACO (Ant colony optimization). We choose shading effect (scientific function), shielding, and openness as objectives for test application. The results show that when the user give a high weight to a particular objective, they can obtain the optimal results with high value of that objective. When we allocate higher weight for the shading effect, the tree plans provide larger shadow value. Even when compared with current tree plan, the study result has a larger shading effect plan. This result will reduce incident radiation to the ground and make thermal friendly open space in the summer. If planners and designers utilize this tool and control the objectives, they would get diverse optimal tree plans and it will allow them to make use of the many environmental benefits from trees.