• Smart Media Journal
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• v.4 no.3
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• pp.9-15
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• 2015

A pub(lish)/sub(scribe) system is a data forwarding system which forwards only interesting data among the whole published data, which is related to the subscriptions registered by end users. Classical pub/sub systems are realized by constructing a network of brokers which are responsible for storing or forwarding data. Along with the substantial increase of the population mobile users, it is required that the pub/sub system handles the subscriptions of user locations which changes continuously and frequently. In this paper, a new broker network based pub/sub system which efficiently handles the frequent changes of subscriptions related to user locations is proposed. In consideration of moving patterns of users and geographical property, the proposed pub/sub system categorize the entire data space into Slow Moving Region and Normal Moving Region, and manages the brokers which are responsible for these regions by using Q+R tree in order to handle user requests more efficiently. Through the extensive simulation, it is presented that the proposed Q+R tree based pub/sub system can reduce unnecessary needs of brokers and network traffic and can support the dynamic subscription related to user location.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3952-3963
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• 2000

This paper considers the WRA(Wavelength and Houting Assignment) problem on all-optical tree networks using WDM(Wavelength Division Multiplexing). Each link between a pair of request nodes on all optical networks is assigned different wavelengths because of technical constraint. On the basis of this, we give an polynomial time algorithm to assign wavelengths to the all patbs of a arbitrary tree network using divide and conquer method. The time complexity of this algorithm is O(Q. R), in which Q is the request nodes for all to'all communication in a tree topology and U is the maximum number of wavelength. Also we implemented our algorithm using C in Pentium II 233MHz and analyzed performance results.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.233-236
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• 2012

모빌리티 인지 퍼브-서브 시스템은 사용자의 관심 위치 정보가 지속적으로 변하는 위치 기반 퍼브-서브 시스템으로써, 스마트 모바일 기기의 대중화와 함께 그 활용도가 부각되고 있다. 이 논문에서는 기존의 위치기반 퍼브-서브 시스템에서 깊이 고려하지 않았던, 관심 위치 정보의 빈번한 변화를 효과적으로 처리하기 위한 브로커 네트워크를 제안한다. 사용자의 행동패턴이나 지리적 특성을 고려해 퍼브-서브 시스템에서 제공하고자 하는 공간 데이터 영역을 Slow Moving Region과 Normal Moving Region의 두가지 타입으로 구분하고, 각 영역에 대한 사용자의 요청을 효과적으로 지원하기 위해 Q+R트리를 사용하여 브로커를 관리한다. 시뮬레이션을 사용한 실험 결과를 통해 제안하는 Q+R트리 기반의 브로커 네트워크가 불필요한 브로커의 로드와 네트워크 트래픽을 감소시킴으로써 보다 효과적으로 지속적인 사용자의 관심 위치 정보 변화를 지원할 수 있음을 확인하였다.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.633-648
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• 1998

The forest vegetation of Mt. Nam Nature Park was investigated according to the phytosociological method. The vegetation in this study area was classified into 5 communities Quercus mongolica (Acer pseudo-sieboldianum subcommunity, Prunus sargentii subcommunity), P. sargentii, Pinus densiflora (Q. mongolica subcommunity, Stephanandra incisa subcommunity) and 5 afforestations Robinia pseudo-acacia, Populus tomentoglandulosa, P. koraiensis, P. rigida, Metasequoia glyptostroboides. Generally, were P. densiflora forest at the Southern slope and Q. mongolica forest at Northern slope dominant species from the top zone standing in Namsan tower. The dominance sequences on each stratum determined by the R-NCD (Relative net Contribution Degree) showed Q. mongolica and P. densiflora in tree-1 layer, Styrax japonica and Corbus alnifolia in tree-2 layer, S. incisa, S. japonica and rhododendron schlipenbachii in shrub layer, and Oplismenus undulatifolius, Eupatorium rugosum, Parthenocissus tricuspidata and Disporum smilacinum in herb layer. The soil was analyzed to investigate the soil conditions and fertility. The pHs of soil collected in each sites appeared strongly acidic with the range of 4.34 to 5.01 each community and especially, was the lowest value 4.34 in P. rigida afforestation. And Q. mongolica-P. sargentii subcommunity was distributed at the area with relative mesic conditions and high organic matters. Nitrogen was highest at P. sargentii community, phosphate at P. densiflora-S. incisa subcommunity, calcium, potasium and magnesium of exchangeble cation at R. pseudo-acacia afforestation. Especially, the level of calcium in R. pseudo-acacia afforestation, P. koraiensis afforestation and P. densiflora community was shown the highest (0.38-1.48 mg/100g) compared to other communities, because of the influence of lime fertilization used to improve acidic soil.

• Journal of the Korean Institute of Landscape Architecture
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• v.21 no.2
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• pp.107-119
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• 1993

This study was conducted to increase to increase the plant species diversity, which was based on the analysis of plant community structure and the survey of human's disturbance degree in Mt. Yongma and Mt. Acha urban nature park, Seoul. The plant community were divided into four groups by TWINSPAN and DCA. These groups were Pinus rigida-P. densiflora community, Quercus mongolica-Q.aliena-Q.accutissima community, Robinia pseudoacaia-Q.accutissima-Poplus${\times}$albaglandulosa community and R.pseudoacacia community. The successional trends of tree species seems to be from P.densiflora, P.rigida, Sorbus alniflora to Q.mongolica, Q.aliena and from P.${\times}$albaglandulosa, R.pseudoacacia, through Q.accutissima, to Q. mongolica, Q.aliena. The species diversity of plant community was high in natual plant community but was low in artificial planting community respectively. Number of species, number of species individuals, indices of species diversity was lowered and soil hardness was increased by the user's trampling, undercutting work and planting P.koraiensis after thinning. In the basis of study results, we proposed the management plan for the urban forest.

• Journal of Environmental Science International
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• v.22 no.10
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• pp.1345-1351
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• 2013

Leaf characteristics of two representative deciduous-tree species in Korean peninsula were compared to assess directional ridge effect on leaf traits of both species. Leaf mass per unit area (LMA) of Rhododendron schilippenbachii in south-facing ridge slope was significantly higher than that in north-facing ridge slope, while Quercus mongolica did not change LMA. Leaf mass of Q. mongolica was increased depending on leaf size irrespective of slope. However, leaf mass of R. schilippenbachii changed differently in responding to expansion of leaf area between both slopes resulting from retardation of leaf expansion in south-facing slope. R. schilippenbachii showed higher leaf nitrogen concentration per unit area (LNCA) in south-facing slope than that in north-facing slope, while Q. mongolica indicated no difference in LNCA between southand north-facing slopes. However, both species revealed no significant difference in leaf nitrogen concentration per unit mass (LNCM) between south- and north-facing slopes. LNCA of Q. mongolica was about two times higher than that of R. schilippenbachii. These results indicate that there is a difference in leaf characteristics including leaf thickness and nitrogen allocation between Q. mongolica and R. schilippenbachii, suggesting the difference of plasticity.

• ETRI Journal
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• v.38 no.1
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• pp.185-194
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• 2016

In this paper, a novel rate control scheme for low delay video coding of High Efficiency Video Coding (HEVC) is proposed. The proposed scheme is developed by considering a new temporal prediction structure of HEVC. In the proposed scheme, the relationship between bit rate and quantization step is exploited firstly to formulate an accurate quadratic rate-quantization (R-Q) model. Secondly, a method of determining the quantization parameters (QPs) for the first frames within a group of pictures is proposed. Thirdly, an accurate frame-level bit allocation method is proposed for HEVC. Finally, based on the proposed R-Q model and the target bit allocated for the frame, the QPs are predicted for coding tree units by using rate-distortion (R-D) optimization. We compare our scheme against that of three other state-of-the-art rate control schemes. Experimental results show that the proposed rate control scheme can increase the Bjøntegaard delta peak signal-to-noise ratio by 0.65 dB and 0.09 dB on average compared with the JCTVC-I0094 and JCTVC-M0036 schemes, respectively, both of which have been implemented in an HEVC test model encoder; furthermore, the proposed scheme achieves a similar R-D performance to Wang's scheme, as well as obtaining the smallest bit rate mismatch error of all the schemes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.3
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• pp.67-74
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• 2012

This study was carried out to cultivate evergreen-leaved tree container seedlings having low cost of equipment and easy to control. Two species of V. odoratissimum var. awabuki and Q. glauca planting in respective underground container were showed survival rate above 90%. The Relative growth rates of height was good in non-treatment and root collar diameter was no significant difference between treatments. The T/R ratio was respectively 1.1, 1.0 in container type of F, G. and root's biomass products was more effective than others. A container type of F showed better Quailty index than others with 16.2 values. Q. glauca was higher T/R ratio in root development than shoot and the quality index was high in container type of E, D with 4.0. 3.5, respectively. On the basis of the results obtained in this study, we can concluded that the underground container type was suitable to F in V. odoratissimum var. awabuki and to D or E in Q. glauca.

• Journal of Korea Foresty Energy
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• v.25 no.1
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• pp.31-38
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• 2006

Quercus mongolica is the most common hardwood species distributed in Korea. This study was conducted to investigate the biomass and energy content of the belowground biomass of Q. mongolica and to obtain the regression equation for estimating root biomass using the tree height and diameter at breast height (DBH). A total of 18 sample trees ranging 20 to 60 year-old were selected in the study sites. Tree height, DBH, age, and weight of stemwood, sapwood, heartwood, stembark, branch, leaf, and root were measured for total biomass. The highly positive correlation was shown between the biomass of most of variables of aboveground components and root biomass. The regression equation of the aboveground total biomass was $log\;W_A\;=\;1.469\;+\;0.992\;log\;D^2H\;(R^2 =0.99)$. The regression equation of the belowground biomass was $log\;W_R\;=\;1.527\;+\;0.808\;log\;D^2H\;(R^2\;=\;0.97)$. The mean energy contents of sapwood, heartwood, bark, leaf, and root were 19,594 J/g DW, 19,571 J/g DW, 19,999 J/g DW, 20,664 J/g DW, and 19,273 J/g DW, respectively. The results obtained from this study can be used to estimate biomass and energy content of belowground using easily measurable variables such as DBH and tree height ranging from 20 to 60-year-old Q. mongolica stands.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.223-236
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• 2003

The vegetation in this study area was divided into 10 plant communities: Pinus thunbergii, P. densiflora, Quercus acutissima, Q. mongolica, Q. serratea, Q. variabilis, Q. aliena, Q. dentata, Carpinus coreana, Betula davurica and 3 afforestations; Pinus rigida, Robinia pseudo-acacia, Castanea crenata. The dominant species in each stratum as determined by R-NCD appeared to be Q. acutissima, P. densiflora, Platycarya strobilacea, Sorbus alnifolia and Q. aliena in the tree-2 layer, Rhododendron mucronulatum, P. strobilacea, Q. serrata, Q. aliena and Q. acutissima in the shrub layer, and Carex lanceolata, C. humilis, R. mucronulatum, Mischanthus sinensis var. purpurascens and Oplismenus undulatifolius in the herb layer. The distribution of diameter at breast height(DBH) showed the highest percentage (56%) in the range of 2∼10㎝ in the study area and it was investigated as being in the restoration phase after disturbance. The average of the age of trees was under 40-years-od. The pH of soil collected at each site appeared to be within the range between 4.53 and 5.10(the average of 4.73) in each community, organic matters appeared higher than the value in Q. mongolica, P. rigida, C. crenata communities compared to P. thunbergii, P. densiflora communities. And soil organic matters and total nitrogen were highly correlated with their contents.