• Analytical Science and Technology
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• v.13 no.6
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• pp.693-698
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• 2000

The object of this series of experiments was aimed for the systematic and long-term radioactivity monitoring through indirect search of C-14 concentration level changes in the natural conditions around the operating nuclear facilities. The result of environmental radioactivity level through tree-ring analysis is increased after operating nuclear facilities and such a level can be proved to relate power generation closely. The measured result of ${\delta}^{13}C$ through the treatment of cellulose can be showed the level -30‰. This figure is very different from one which is measured the -17‰ of air sample by passive air sampling and -8‰ of air sample by active air sampling. And these differences can be assumed as isotope fractionation by photosynthesis, but the problem is more study as needed.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.77-82
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• 2002

This study was carried out in order to produce useful material for the forest multiple use and forest protection by physico-chemical soil analysis of studied area in Sokwang-ri Forest Genetic Resource Protection Forest which was divided into in standard plots include Tricholoma matsutake and Sarcodon aspratus production forest. The result of physico-chemical soil analysis represented as following. The soil type of T. matsutake production forest was Dry brown forest soil(B1), while on the other hand the soil type of S. aspratus production forest was Moderately moist brown forest soil(B3). Between T. matsutake and S. aspratus production forest did not result in significant changes in soil pH(5.22-5.60) and soil depth(47cm), but available phosphorus, carbon, and nitrogen contents were different results. CN ratio of the fairy ring of T. matsutake was quite lower than that in S. aspratus production forests, which indicated that T. matsutake production forest was built up in the relatively immature soils which contain little organic matter. Generally, it was predicted that Pinus densiflora for. erecta forest succeeded to deciduous tree forest in stable soil environments. To conserve these T. matsutake and S. aspratus production forest, the contents of available phosphorous and exchangeable cation should be increased by continuous soil environment management and it should be established the secondary growth forests of old aged Pinus densiflora for. erecta trees as soon as possible.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.241-252
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• 2018

It was estimated that the Imdang-dong site of Gyungsan was constructed in the 2nd to 4th century based on excavated layers and artifacts. This study was carried out to verify the result using the dendrochronological analysis of six wooden pillars excavated at the site. As a result, it was proven that 6 specimens were not cut at the same age because their tree-ring chronologies were not synchronized each other. And more, it was reconfirmed in wiggle matching dating as confirming two of them were dated to A.D. 94-135 and A.D. 224-289, respectively. It was coincided with the above-mentioned estimated age. In wood identification, most of them were identified as Hovenia dulcis Thunb., Tilia spp., Ulmus spp. which grow usually under cool environment. Based on the result, we could conclude that the climate at that time was cooler than the present.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.618-629
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• 2000

This study was carried out to investigate ecological niche of Quercus acuta communities in Bogildo-island from July to October, 1998. This island is occupied by a subtropical evergreen broad-leaved forests. The study on community ecology of Q. acuta, mostly dominant species of subtropical forests, is very important for successful forest management. Sampling areas were selected in 16 quadrats, dominated by Q. acuta to examine the vegetation characteristics(plant identification, D.B.H.) and environmental elements (microtopography, altitude, slope degree, aspect, illumination and soil physicochemical properties). On the basis of data from field surveys, importance values were calculated for the dominance of Q. acuta and volume growth was analyzed by tree ring widths. The results obtained were as follows ; 1. The lists of vascular plants in the investigations were identified as 54 families, 91 genera, 113 species, 9 varieties, 1 formae. It appeared that 45 kinds were evergreen, 6 kinds(Camellia japonica, Ligustrum japonicum, Eurya japonica, Smilax china, Trachelospermum asiaticum var. intermedium, Carex lanceolata) were commonly observed in all plots and 5 species(Cinnamomum japonicum, Ardisia japonica, Cymbidium goeringii, Dryopteris bissetiana, Viburnum erosum) were most highly observed in all plots(over 80%). 2. The dominating species per strata were, Quercus acuta, Castanopsis cuspidata sp. Quercus salicina, Pinus thunbergii, Prunus sargentii in tree layer, Camellia Japonica, Ligustrum japonicum, Quercus acuta, Eurya japonica, Castanopsis cuspidata sp. in subtree layer, Camellia japonica, Ligustrum japonicum, Smilax china, Cinnamomum japonicum, Viburnum erosum in shrub layer and Trachelospermum asiaticum var. intermedium, Ardisia japonica, Carex lanceolata, Camellia japonica(seedlings), Quercus acuta(seedlings) in herb layer, all in descending orders. 3. Quercus acuta could be suggested as shade intolerant tree, considering the distribution in southern, western, nothern and eastern slopes in the descending orders. 4. Mean relative illumination in the forest is 0.89 % and it is relatively low in brightness. 5. Sustainment of Quercus acuta community couldn't be confirmed by judging from their reverse J curve in even-aged forest, as shown in D.B.H. distribution analysis. 6. The result of annual ring width analysis(mean ; 2.44 mm) showed three stages, such as a gentle increasing(1~12 year ; 2.04 mm), a relatively steep increasing(13~22 year ; 2.95 mm) and decreasing or stagnating(23 year after ; 2.41 mm).

• Journal of Mushroom
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• v.22 no.1
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• pp.22-26
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• 2024

Tricholoma matsutake is a traditional favorite food in East Asia, cultivated in fairy rings called "shiro," which are found near Pinus densiflora. For effective artificial cultivation of Tri. matsutake, microorganisms from symbiotic fairy rings are co-cultivated. In this study, one bacterial isolate (Y22_B35) and two fungal isolates (Y22_F64 and Y22_F68) displayed growth-promoting effects on Tri. matsutake mycelium (158.47, 125.00, and 122.26% enhanced growth, respectively). For identification, 16S rRNA or ITS regions from the microorganisms¡¯ genomes were sequenced. Other sequences, including BenA, CaM, and RPB2 were sequenced in the fungal isolates. The bacterial isolate Y22_B35 was identified as Bacillus cereus. Y22_F64 and Y22_F68 were identified as Umbelopsis nana and Aspergillus parvulus, respectively. To identify the effects of the dominant microorganisms on Tri. Matsutake cultivation, metagenomic analyses were performed. Discovery of these Tri. matsutake mycelium growth-promoting microorganisms and metagenomics analyses are expected to contribute to our understanding of Tri. matsutake fruiting body growth and construction of biomimicry.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.1
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• pp.5-25
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• 2009

In recent years the popularity of multi-hop wireless networks has been growing. Its flexible topology and abundant routing path enables many types of applications. However, the lack of a centralized controller often makes it difficult to design a reliable service in multi-hop wireless networks. While packet routing has been the center of attention for decades, recent research focuses on data discovery such as file sharing in multi-hop wireless networks. Although there are many peer-to-peer lookup (P2P-lookup) schemes for wired networks, they have inherent limitations for multi-hop wireless networks. First, a wired P2P-lookup builds a search structure on the overlay network and disregards the underlying topology. Second, the performance guarantee often relies on specific topology models such as random graphs, which do not apply to multi-hop wireless networks. Past studies on wireless P2P-lookup either combined existing solutions with known routing algorithms or proposed tree-based routing, which is prone to traffic congestion. In this paper, we present two wireless P2P-lookup schemes that strictly build a topology-dependent structure. We first propose the Ring Interval Graph Search (RIGS) that constructs a DHT only through direct connections between the nodes. We then propose the ValleyWalk, a loosely-structured scheme that requires simple local hints for query routing. Packet-level simulations showed that RIGS can find the target with near-shortest search length and ValleyWalk can find the target with near-shortest search length when there is at least 5% object replication. We also provide an analytic bound on the search length of ValleyWalk.

• Journal of Conservation Science
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• v.8 no.1 s.11
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• pp.16-22
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• 1999

Species of 741 charcoal samples, which were excavated from the dwelling sites of the bronze age $(about\;2500\~3100\;B.P)$ at Hyeonwha-ri, Pyungteak, Korea, were identified. Most of samples were deciduous oaks (Quercus spp.; $97.7\%$) and others were alders (Ainus spp.; $1.9\%$) and soft pines (Pinus spp.; $0.4\%$). Tree rings of nine largest samples were also examined. The numbers of annual rings were 8 to 36 and mean ring width was rather narrow $(0.65\~1.82\;mm)$. Most samples possessed pith and tylosis. The results indicate that logs 10 to IS cm diameter had been used for the poles of houses without further processing.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.425-425
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• 2011

가뭄은 짧게는 한 계절에서 1년, 길게는 10년 이상 지속되는 등 시간 규모가 다양하며, 그 시작과 끝을 명확하게 정의하기 힘든 특성이 있다. 이와 같이 나타나는 가뭄의 장기적 발생 특성으로 인해 지역의 가뭄 특성을 정확하게 분석하기 위해서는 장기간의 자료를 필요로 한다. 그러나 우리나라의 경우 근대적인 관측은 1900년대 초반에 시작되었으며, 현재 운영 중인 대부분의 관측 시설은 1970년대부터 이용 가능한 자료가 존재하는 상황이다. 미국의 경우에도 1800년대 후반부터 관측된 자료를 이용하여 가뭄 및 홍수 분석을 수행하고 있는 실정이다. 이러한 점을 보완하여 보다 장기간의 가뭄 특성 관련 정보를 확보하기 위한 노력이 많은 연구자들을 통해 지속되어 왔다. 강수량이나 유출량 등 근대 관측 이후 이용이 가능한 자료를 통해서도 가뭄과 관련된 유용한 정보를 획득할 수 있으나 보다 장기간의 정보를 확보하기 위해 나이테 등 다양한 기후 지표를 이용한 연구가 수행되고 있다. 특히 과거 가뭄 특성에 대한 복원을 위해 나이테자료를 이용하는 연구는 미국을 중심으로 매우 활발히 이루어지고 있다. 또한 몽골이나 티베트, 중국 등과 같이 근대 기상 관측 자료가 매우 부족한 지역을 대상으로 가뭄 특성을 분석하기 위해 해당 지역에서 확보된 나이테 자료를 이용하는 연구가 매우 활발하다. 그러나 우리나라에서는 나이테자료와 가뭄 특성 간 관계를 검토하고 나이테자료에 근거하여 과거 가뭄 특성을 복원하려는 노력이 거의 전무한 실정이라 할 수 있다. 따라서 본 연구에서는 근대 관측 이전에 대한 가뭄 특성을 복원함에 있어 나이테자료의 활용가능성을 파악하기 위해 가뭄 특성을 나타내는 가뭄지수와 나이테자료의 상관관계를 분석하였다. 이를 위해 우리나라 및 주변 국가에서 확보된 나이테자료를 이용하였으며, PDSI, SPI 등 기존 가뭄지수를 분석에 함께 활용하였다. 본 연구에서 제시된 연구결과는 향후 나이테자료를 기반으로 근대 관측 이전에 대한 가뭄 특성을 복원하는데 있어 유용한 기반 정보로 활용될 수 있을 것으로 판단되며, 나이테자료 등 기후지표를 이용한 가뭄 관련 연구의 기초 정보로 이용될 수 있을 것이다.

• Journal of Korea Water Resources Association
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• v.37 no.1
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• pp.55-66
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• 2004

The Hapchon Dam, located upstream of the Hwang River, Korea, was constructed in December, 1988. Due to the lack of storage of water, the dam gate has not been operated during last ten years. Thus, a new ecosystem has been established at the downstream part of the dam. This is not a common phenomenon which can be found elsewhere in the country. The present study investigates the effect of flow regime change on the river morphology and vegetation cover in the downstream river reach after the dam construction. The analysis of flow regime is carried out, and the changes in bed elevation and in channel cross sections are examined. Site investigations including tree ring tests are also performed. The increase in the vegetation cover is estimated by comparing aerial photographs taken before and after dam construction.

• The Korean Journal of Ecology
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• v.1 no.2
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• pp.66-71
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• 1977

The growth of red and black pines in Muan, Seochen, Gapyeong and Kochang areas was compared by means of the growth of annual ring width and stem analysis to study the process of damages caused by pine needle gall midge. Red pine forest of Seocheon area began to suffer by pine needle gall midge from 1961 and the damage was to becoming severe from 1967. The damage became so intense tha tmany forests are withering to death from spring of 1975. Black pine forest also began to suffer from 1973. Red pine forest of Muan area was supposed to be suffered from 1973. Red pine forest of Kochang area suffered by pine needle gall midge from 1967. It seems that the damage became severe from 1973 and that black pine forest was also badly damaged from that time. Red pine forest of the control plot, Gapyeong area, began to suffer from 1967 and it also became intense from 1973. Although the areas of Seocheon, Muan, Kochang, and Gapyeong are different from each other in terms of locality and the infitration period of pine needle gall equally from 1967 due to mass development of population or other factors and the damage became more intense from 1973. Black pine forest was also badly damaged from that time. Black pine seems to be stronger in insect resistant than red pine. This can be justified by the fact that it began to suffer belatedly in each area and the degree of damage is moderate. The damage of Seocheon area is the severest following Kochang. Muan area is relatively moderate but the forest becoming decrease in growth.