• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.677-679
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• 2017

Data convergecast is an indispensable task for any WSN applications. Typically, scheduling in the WSN consists of two phases: tree construction and scheduling. The optimal tree structure and scheduling for the network is proven NP-hard. This paper focuses on the delay optimality while constructing the data convergecast tree. The algorithm can take any tree as the input, and by performing the switches (i.e. a node changes its parent), the expected aggregation delay is potentially reduced. Note that while constructing the tree, only the in-tree collisions between the child nodes sending data to their common parent is considered.

• Communications for Statistical Applications and Methods
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• v.18 no.6
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• pp.809-816
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• 2011

A tree-indexed autoregressive(AR) process is a time series defined on a tree which is generated by a branching process and/or a deterministic splitting mechanism. This short article is concerned with conditional heteroscedastic structure of the tree-indexed AR models. It has been usual in the literature to analyze conditional mean structure (rather than conditional variance) of tree-indexed AR models. This article pursues to identify quadratic conditional heteroscedasticity inherent in various tree-indexed AR models in a unified way, and thus providing some perspectives to the future works in this area. The identical conditional variance of sisters sharing the same mother will be referred to as the branching heteroscedasticity(BH, for short). A quasilikelihood but preliminary estimation of the quadratic BH is discussed and relevant limit distributions are derived.

• ETRI Journal
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• v.43 no.6
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• pp.1024-1037
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• 2021

Mining high utility itemsets (HUIs) from transaction databases considers such factors as the unit profit and quantity of purchased items. Two-phase tree-based algorithms transform a database into compressed tree structures and generate candidate patterns through a recursive pattern-growth procedure. This procedure requires a lot of memory and time to construct conditional pattern trees. To address this issue, this study employs two compressed tree structures, namely, Utility Count Tree and String Utility Tree, to enumerate valid patterns and thus promote fast utility computation. Furthermore, the study presents an algorithm called single-phase utility computation (SPUC) that leverages these two tree structures to mine HUIs in a single phase by incorporating novel pruning strategies. Experiments conducted on both real and synthetic datasets demonstrate the superior performance of SPUC compared with IHUP, UP-Growth, and UP-Growth+algorithms.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.844-847
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• 2010

FP-tree는 연관성 규칙 알고리즘 전체의 성능을 향상 시키며 DB 스캔을 단 2회로 줄였다. 하지만 빈발 항목과 모든 트랜잭션의 tree 정보를 메모리에 상주 시키면서 많은 메모리 공간을 요구했다. 그래서 나온 DRFP알고리즘은 메모리 요구 문제를 저장장치에 저장함으로 해결 하였으나 FP-tree와는 달리 시간 성능에서의 문제점을 가졌다. 그래서 우리는 이러한 문제점을 보완할 NRFP-tree(Nare disc-Resident Frequent pattern Tree)를 제안한다.

• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.2
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• pp.79-86
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• 1999

This study was carried out to estimate the area of damaged forest and the volume of stand tree in burned area, Mt. Weol-A in eastern Chinju, Korea using digital maps derived from supervised classification of Landsat thematic mapper(TM) imagery as reference data. Criterion laser estimator and WinDENDRO$^{tm}$(v. 6.3b) system as a computer-aided tree ring measuring system were used to measure a volume and age of sampled tree. The sample site had been chosen in unburned areas having the same terrain condition and forest type of burned areas. The tree age, diameter at breast height, tree height and volume of the sample tree selected from sample site in unburned area were 27years, 20.9cm, 9.7m and $0.1396m^3$ respectively. Total stand volume of sample site was estimated $2.9316m^3$/0.04ha, Damaged stand volume evaluated to about $16,007m^3$ in the burned area of 218.4ha.

• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1437-1449
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• 2023

The purpose of this study is to analyze whether pervious and impervious areas in urban areas affect tree growth. In order to determine the differences in the growth of six species of trees planted simultaneously, the effects of pervious and impervious surfaces on tree growth were analyzed using the Normalized Difference Vegetation Index (NDVI) produced using Sentinel-2 and sub-divided land cover map from the Ministry of Environment. For this purpose, the Geospatial eXplainable Artificial Intelligence(GeoXAI) concept was applied. As a result of the analysis, the explanatory power of the model was found to be the best when considering the area of land cover included in the 10m range for Pinus densiflora, the 20 m range for Zelkova Serrata, Metasequoia glyptostroboides, and Ginkgo biloba, the 30 m range for Platanus occidentalis, and the 40 m range for Yoshino cherry trees. In addition, the wider the pervious area, the more active the growth of trees,showing a positive correlation, and the wider the impervious area, such as nearby artificial ground, showed a negative correlation with tree growth. This shows that surrounding pervious and impervious areas affect the growth of trees and that the scope of influence varies depending on the tree species.

• Landscaping Tree
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• s.119
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• pp.12-14
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• 2010

제주도, 완도 등 남부해안 지역의 표고 200~700m의 해변과 산록에서 자생하는 상록활엽교목으로 수고 15m, 직경 1m에 달하는 나무로 잎 표면은 녹색의 윤채가 있고, 뒷면은 연한 연갈색의 인모가 있어 관상학적으로 우수한 수종이다. 따라서 남해안 지역에서 가로수 및 정원수로 많은 사랑을 받고 있으며, 병해충에도 비교적 강한 수종으로 알려져 있다. 또한 가을과 겨울에는 혼자만이 꿋꿋이 녹색을 띠면서 적막한 해안도로의 거리를 조금이나마 부드럽고 훈훈하며 따뜻한 느낌을 주는 나무이다. 이러한 구실잣밤나무가 다량으로 식재된 까닭에 최근 구실잣밤나무를 가해하는 해충들이 많이 발생하여 방제에 도움을 주고자 주요해충에 대한 생태 및 방제법을 간략하게 소개하고자 한다.

• Landscaping Tree
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• s.96
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• pp.16-18
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• 2007

전.남북, 경.남북, 제주도, 울릉도 등 남부 도서지방의 표고 700m이하에서 자라는 상록활엽고목으로 수고 20m, 직경 1m까지 자란다. 특히 일부 지자체에서는 지방을 상징하는 나무로 지정되어 주민의 사랑을 받고있다. 녹나무과에 속하는 후박나무는 잎이 광택을 띠며, 봄에 나는 새순은 단풍과 같이 붉게 물들어 아름답다. 가로수, 조경수로 많이 식재되고 있어 봄과 여름에는 다른 수종들과 어울러져 남들을 더욱 돋보이게 하고 가을과 겨울에는 혼자만이 꿋꿋이 녹색을 띠면서 적막한 도시의 거리를 조금이나마 부드럽고 훈훈하며 따뜻한 느낌을 주는 나무이다. 이러한 후박나무를 가해하는 해충으로 나무좀류와 기타 해충에 대한 생태 및 방제법을 간략하게 소개하고자 한다.

• Proceedings of the KSR Conference
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• 2006.05b
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• pp.1179-1187
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• 2006

• Journal of Forest and Environmental Science
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• v.32 no.2
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• pp.189-195
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• 2016

Logging equipment and method have a major influence on harvesting productivity and cost. This study investigated the productivity and operational costs of tree-length cable yarding system using HAM300, a domestically developed tower yarder. We tested HAM300 for thinning operation in Pinus densiflora stands at Gangreung, Gangwon-do on April, 2014. To assess the productivity we conducted time study for each stage of the operation. When the average time/cycle was examined for each stage of the operation, the longest was for yarding (241 sec), followed by delimbing (237 sec), felling (153 sec), and processing (103 sec). Furthermore, productivity for felling was $8.6m^3/hr$, followed by delimbing ($5.1m^3/hr$), yarding ($3.5m^3/hr$), and processing ($8.1m^3/hr$). The total cost for the tree-length logging system was $58,446won/m^3$, of which the majority was incurred by the yarding cost at $46,217won/m^3$ (79.3%), whereas the lowest cost was for felling at $2,359won/m^3$ (4.1%). We suggest that it is necessary to foster specialized operators and provide training in operating the tower yarder thereby implementing efficient harvesting system resulting from low-cost yarding.