• Journal of Korea Game Society
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• v.13 no.4
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• pp.25-34
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• 2013

Spatial partitioning trees are needed for processing collision detections efficiently. In order to select split planes for spatial partitioning trees, the tree balance and the number of polygons overlapped with the split plane should be considered. In this paper, the heuristic algorithm controlling weight values of tree build criteria is proposed for spatial partitioning trees of 3D games. As the weight values are changed, tree build time, T-junction elimination time which can cause visual artifacts in splitting polygons overlapped with the split plane, rendering speed (frame per second: FPS) according to tree balance are analysed under 3D game simulations.

• Journal of the Korean Data and Information Science Society
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• v.23 no.5
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• pp.949-959
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• 2012

This article is to find the right size of decision trees that performs better for boosting algorithm. First we defined the tree size D as the depth of a decision tree. Then we compared the performance of boosting algorithm with different tree sizes in the experiment. Although it is an usual practice to set the tree size in boosting algorithm to be small, we figured out that the choice of D has a significant influence on the performance of boosting algorithm. Furthermore, we found out that the tree size D need to be sufficiently large for some dataset. The experiment result shows that there exists an optimal D for each dataset and choosing the right size D is important in improving the performance of boosting. We also tried to find the model for estimating the right size D suitable for boosting algorithm, using variables that can explain the nature of a given dataset. The suggested model reveals that the optimal tree size D for a given dataset can be estimated by the error rate of stump tree, the number of classes, the depth of a single tree, and the gini impurity.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.3
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• pp.380-388
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• 1999

본 논문에서는 완전삼트리를 재귀원형군에 임베딩하는 문제를 고려한다. 재귀원형군 G(N,d)는 N개의 노드와 N보다 작은 d의 거듭제곱에 의한 점프에지를 가지는 원형군그래프이다. 임베딩 문제를 해결하고자 본 논문에서는 노드수가 3k인 삼항트리 Tk새롭게 도입한다. 먼저 N개 이하의 정점을 가지는 삼항트리가 G(N, 2)와 G(N,3)의 부그래프임을 보인다. 또한 완전 삼진트리가 삼항트리에 연장률 2, 확장률2, 밀집률 2로 임베딩됨을 보인다. 이러한 결과들을 결합하면서 N개 이하의 정점을 가지는 완전삼진 트리가 재귀원형군G(2N, 2)과 G(2N, 3)에 연장률 2, 밀집률 2로 임베딩 가능하게 한다. 임베딩 과정에서 이용된 삼항트리는 2 -포트 방송모델에서 최소방송트리임을 보이고, 이를 이용하여 재귀원형군 G(2m, 2)가 2-포트 방송모델에서 최소방송시간을 가짐을 보인다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.252-257
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• 2007

MusicXML은 다양한 전자악보 형식들이 음악을 악보로 표현하는데 있어 지니는 한계를 잘 극복하면서 응용성, 확장성 및 공개성 등의 장점으로 인해 현재 전자악보의 표준으로 가장 적합한 것으로 평가되고 있는 악보 형식이다. 그러나 MusicXML은 XML을 기반으로 한 텍스트 데이터이기 때문에 이러한 악보 형식을 실제 악보로 변환하거나 연주하는 것은 물론 실제 악보 내용을 기반으로 한 악보 검색이 용이하도록 적절한 데이터 구조로 표현하는 것이 필요하다. 본 논문에서는 MusicXML 악보에 대하여 다차원 속성 정보를 가진 데이터의 표현에 용이한 k-d 트리 기반 데이터 구조로 표현하는 방법을 제안한다. 논문은 또한 악보에 대한 k-d 트리 구조를 보다 다양한 응용에 활용할 수 있도록 k-d 트리를 확장하여 구조화하는 방법을 제시한다. 본 논문에서 제안한 방법은 특히 내용을 기반으로 한 악보 정보 검색에 유용하게 이용될 수 있다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2253_2254
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• 2009

무선 모바일 통신 시장의 성장에 따라 수동 소자로 구성된 모듈에 대한 관심이 높아지고 있다. 본 논문에서는 수동소자를 이용한 Wi-MAX용 트리플렉서를 설계하였다. 트리플렉서는 Wi-MAX의 RF Front-end단 앞부분에 연결되며, IEEE 802.16에 따른 2GHz, 3GHz, 5GHz 대역을 선택, 분리해주는 역할을 한다. 제안된 트리플렉서는 저역통과필터, 대역통과필터, 고역통과필터로 구성하였으며, 수동소자의 최소화로 인해 삽입손실 향상을 중점으로 설계하였다. 회로해석 결과, 각 대역별 (2/3/5GHz) 삽입손실은 각각 -0.5dB, -0.6dB, -0.4dB 였으며, 반사손실은 -20dB, -20dB, -12dB, 격리도는 -20dB, -24dB, -25dB의 특성을 보였다. 수동 소자의 최소화 설계로 인해 모듈 및 시스템의 저가화를 기대할 수 있다.

• Spatial Information Research
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• v.7 no.2
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• pp.271-282
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• 1999

In this paper, we derived an efficient indexing scheme, SJ tree, which handles multi-attribute data and spatial join operations efficiently. In addition, a number of algorithms for manipulating multi-attribute data are given , together with their computational and I/O complexity . Moreover , we how that SJ tree is a kind of generalized B-tree. This means that SJ-tree can be easily implemented on existing built-in B-tree in most storage managers in the sense that the structure of SJ tree is like that of B-tree. The spatial join operation with spatial output is benchmarked using R-tree, B-tree, K-D-B tree, and SJ tree. Results from the benchmark test indicate that SJ tree out performance other indexing schemes on spatial join with point data.

• The KIPS Transactions:PartA
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• v.8A no.3
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• pp.209-216
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• 2001

The effective way to apply incremental attribute grammar to a complex language process is the use of optimized algorithm. In optimized algorithm for incremental attribute grammar, the new input attribute tree should be exactly compared with the previous input attribute tree, in order to determine which subtrees from the old should be used in constructing the new one. In this paper the new optimized algorithm was reconstructed by analyzing the algorithm suggested by Carle and Pollock, and a generation process of new attribute tree d’copy was added. Through the performance evaluation for the suggested matching algorithm, the run time is approximately improved by 19.5%, compared to the result of existing algorithm.

• Journal of Korea Multimedia Society
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• v.10 no.11
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• pp.1367-1383
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• 2007

A sensor network consists of a network of sensors that can perform computation and also communicate with each other through wireless communication. Some important characteristics of sensor networks are that the network should be self administered and the power efficiency should be greatly considered due to the fact that it uses battery power. In sensor networks, when large amounts of various stream data is produced and multiple queries need to be processed simultaneously, the power efficiency should be maximized. This work proposes a technique to create an index on multiple monitoring queries so that the multi-query processing performance could be increased and the memory and power could be efficiently used. The proposed SMILE tree modifies and combines the ideas of spatial indexing techniques such as k-d trees and R+-trees. The k-d tree can divide the dimensions at each level, while the R+-tree improves the R-tree by dividing the space into a hierarchical manner and reduces the overlapping areas. By applying the SMILE tree on multiple queries and using it on stream data in sensor networks, the response time for finding an indexed query takes in some cases 50% of the time taken for a linear search to find the query.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.5
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• pp.481-486
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• 2014

This study aims at enhancing the performance of file-referring octree, suggested by Han(2014), for efficiently querying huge 3D point clouds, acquired by the 3D terrestrial laser scanning. Han's method(2014) has revealed a problem of heavy declining in query speed, when if it was applied on a very long tunnel, which is the lengthy and narrow shaped anisometric structure. Hereupon, the shape of octree has been analyzed of its influence on the query efficiency with the testing method of generating an independent octree in each isometric subdivision of 3D object boundary. This method tested query speed and main memory usage against the conventional single octree method by capturing about 300 million points in a very long tunnel. Finally, the testing method resulted in which twice faster query speed is taking similar size of memory. It is also approved that the conclusive factor influencing the query speed is the destination level, but the query speed can still increase with more proximity to isometric bounding shape of octree. While an excessive unbalance of octree shape along each axis can heavily degrade the query speed, the improvement of octree shape can be more effectively enhancing the query speed than increasement of destination level.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.433-439
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• 2012

In this paper, we proposed the triplexer using unit-cell of CRLH transmission line which has a bandpass characteristic to reduce adjacent channel interference. The input impedance of triplexer with each channel filter is operated open-circuit at the resonance frequencies of other channels. Such property is due to the combination a series and parallel resonance circuits of CRLH-TL unit-cell. The measured triplexer results are showed a measured insertion loss of each channel, less than 1.5 dB, matching at each port, less than 15dB and isolation between channel, better than 25 dB. Also, to validate the triplexer, a small signal amplifier with triple-band is designed and tested. the measured amplifier results show good agreements with prediction.