• Journal of Convergence for Information Technology
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• v.10 no.3
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• pp.16-21
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• 2020

This paper describes the jamming characteristics of a stand-off jammer jamming the LPI radar. The LPI radar reduces the side lobes of the receiving antenna to reduce the effect of jamming. It is easy a radar to predict the effect of jamming on a self-protection jammer where the jammer is in the same position as the target. However, for stand-off jammer jamming at different locations from the target, the prediction of jamming effect is complex. In this paper, the jamming effect of LPI radar is analyzed using signal to jamming ratio and burn-through range. Also, when the antenna's side lobe decreases below -30 dB, the stand-off jamming effect in the side lobe direction is weak. So we proposed a new jamming method for the main lobe and analyzed the jamming effect. This study is expected to be useful for the design and operation of aircraft jammers.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• autumn
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• pp.115-117
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• 2004

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.767-775
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• 2016

Wood properties are affected by environmental factors such as soil, topography, rainfall, and climate change. The physical and mechanical properties of Quercus glauca were analyzed in order to investigate the relationship between wood properties and forest stand characteristics related to regions and forest origins. Physical and mechanical properties of wood were influenced by region. And no significant difference was observed between natural and artificial forests with respect to wood quality properties. Therefore, these findings are expected to be useful as fundamental data for silviculture practices of these species for wood quality.

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.67-77
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• 2010

Stand structure and spatial associations of the dominant tree species in Quercus mongolica stands were investigated to understand interspecific relationships and the persistent dominance of Q. mongolica. We examined the species composition, DBH (diameter at breast height) distribution, and spatial distribution of trees (${\geq}\;2.5\;cm$ DBH) in two permanent $100\;m\;{\times}\;100\;m$ plots in Q. mongolica-dominant stands on the western part of Mt. Jiri. Ripley's K-function was used to characterize the spatial patterns and associations of dominant tree species. Q. mongolica showed a continuous and reverse-J shaped DBH distribution with clumped spatial distribution in both study sites. Q. mongolica and Abies koreana exhibited a negative association implying potential interspecific competition. The positive spatial association between Q. mongolica and Alnus hirsuta var. sibirica and Fraxinus sieboldiana were affected by site characteristics: limited habitat conditions with a large proportion of rock surface. Our results suggest that interactions among species were complex and ranged from positive to negative. Differences in stand and site characteristics and regeneration mechanisms among the species play an important role in regulating their spatial distribution patterns, while competition between individuals also contributes to spatial patterning of these communities. The high density and the early developmental stage of spatial distribution and structural characteristics of Q. mongolica and the relatively low importance values of other species in the stands imply that Q. mongolica will remain dominant in the study sites in the near future.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.714-720
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• 2015

Since physical and mechanical properties of wood are affected by environmental factors such as soil and climate change, this study investigated relationships between wood quality factors and stand characteristics of Castanopsis cuspidata var. sieboldii forest in the southern region of Korea, including Jeollanam-do Province and Je-ju island. The obtained results found very close relationships between physical and mechanical properties of wood and stand characteristics. The air-dried density and strength performance of woods showed a negative correlation with the diameter at breast height (DBH) while they were positively related to altitude and drainage of the forest site. And wood properties showed variations depending on the region. These results brought a conclusion that wood of Castanopsis cuspidata var. sieboldii in the southern region could be useful forest resources for timber production.

• Journal of the Korean Institute of Landscape Architecture
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• v.13 no.1
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• pp.43-66
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• 1985

Korea needs proper and rational public policies on conservation and use of forest land and other natural resources because of the accelerating expansion of national land developments in recent years. Unfortunately, there is no systematic planning system to support the needs. Generally, forest land use planning needs suitability analysis based on efficient land classification system. The goal of this study was to classify a forest land using multivariate satistical methods. A case study was carried out in winter of 1983 on a mountainous area higher than 100m above sea level located at Mt. Kwanak in Anyang -city, Kyung-gi-do (province). The study area was 19.80 km$^2$wide and was divided into 1, 383 Operational Taxonomic Units (OTU's) by a 120m$\times$120m grid. Fourteen descriptors were identified and quantified for each OTU from existing national land data : elevation, slope, aspect, terrain form, geologic material, surface soil permeability, topsoil type, depth of the solum, soil acidity, forest cover type, stand size class, stand age class, stand density class, and simple forest soil capability class. For this study, a FORTRAN IV program was written for input and output map data, and the computer statistics packages, SPSS and BMD, were used to perform the multivariate statistical analysis. Fourteen variables were analyzed to investigate the characteristics of their fire quench distribution and to estimate the correlation coefficients among them. Principal component analysis was executed to find the dimensions of forest land characteristics, and factor scores were used for proper samples of OTU throughout the study area. In order to develop the classes of forest land classification based on 102 surrogates, cluster and discriminant analyses of principal descriptor variable matrix were undertaken. Results obtained through a series of multivariate statistical analyses were as follows ; 1) Principal component analysis was proved to be a useful tool for data selection and identification of principal descriptor variables which represented the characteristics of forest land and facilitated the selection of samples.

• Food Science of Animal Resources
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• v.40 no.1
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• pp.74-86
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• 2020

Horse meat is nutritionally adequate to the elderly, but it has a comparatively hard texture in contrast to most of the food. In practice, the meat intake in the elderly is generally bated because the relatively difficult texture of the meat can diminish mastication. Thus, strategies are being developed to produce meat products remanding detracted mastication exertion and possibly exalt ingestion and nutritional stand, in the elderly. Hence, the effects of enzymes on textural characteristics of horse meat were studied, because they have well-known favorable efficacy on the meat tenderness by causing important demotion of the myo-fibrillar protein and collagen. Four treatments namely, papain, bromelin, pepsin, and pancreatin, alongside one control were invoked to the horse meat. Their effects on the texture parameters were determined. All the above enzymatic treatments significantly reduced hardness and resilience (p<0.001). These results present opportunities to produce essential fatty acids fortified horse meat with soft texture and satisfied technological characteristics. The intake of the essential fatty acids intensified horse meat could aid the elderly to get their aimed essential fatty acid demands. Results also suggest that horse meat tenderized through enzymatic processing stand for auspicious options for the comprehension of texture-revised diets in the elderly population.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1338-1345
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• 2009

Although rock excavation is necessary for the effective utilization of urban space, most conventional rock excavation methods, including the blasting method, cause high noise and vibration. Meanwhile, if a high pressure waterjet system is applied to excavate underground spaces in urban areas, the public grievance can be reduced by low noise and vibration. In this study, an abrasive waterjet system is designed and developed to study the influence of various performance parameters such as jet pressure, nozzle traverse speed, stand-off distance, or abrasive feed rate on waterjet excavation performance in laboratory. Using the developed waterjet system, rock drilling characteristics are identified by measuring drilling depths as a function of the jet exposure time. The drilling depth linearly increases with increasing the jet exposure time(under 60sec). Rock cutting characteristics are also obtained with various jet pressures(1600~3200kg/$cm^2$) and nozzle traverse speeds(1.9~14.1mm/s): The cutting depth is nonlinearly related to the jet pressure and traverse speed. Indeed, the cutting depth increases with an increase in the jet pressure and a decrease in the nozzle traverse speed. This trend can be explained by energy transferring/loss mechanism.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.7-17
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• 2009

The objectives of this study were to analyze vegetation type and stand structure of the red pine (Pinus densiflora) in Kangwon northern region for stable and sustainable management forests. The pine forests in study sites were classified into 3 communities, 5 groups, and 2 subgroups, total 7 vegetation units. Species with constance degree of more than 61% were P. densiflora, Quercus mongolica, Lindera obtusiloba, Spodiopogon sibiricus, Atractylodes japonica, Rhododendron mucronulatum, and Carex humilis. They were showing different characteristics by pattern according to their growing district. In the importance value (I.V.) analysis of each layer, P. densiflora showed highly in tree layer while in other layers Quercus spp. was high. Especially, young P. densiflora tree hardly appeared in the herb layer, but broad-leaved trees and shrub species showed high I.V.. Furthermore, the annual ring growth of P. densiflora was reduced while that of Q. spp. increased. According to analysis of stand structures and annual ring growths, it is considered that appropriate silvicultual practice methods should be employed to remove rival broad-leaved species for maintenance of sustainable red pine forests considering the characteristics of each stand.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.184-187
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• 2004

In case of a semi-forcing culture for vegetable perilla, the following research results on the effect of black polyethylene mulching, the optimum sowing season, and the seedling stand improvement method were drawn. Soil temperature was higher and the emergence was faster in a black polyethylene mulching culture than in a non-mulching culture. However, the mature was late, the main stem were larger, and the seed yield, as well as the leaf yield, was greater in a mulching culture than in a non-mulching culture. Considering growth and chilling injury, the stable sowing season of vegetable perilla was judged to be the early in January. The covering materials for improvement of the seedling stand can be a non-woven fabric and hyaline polyethylene. However, the non-woven fabric seemed to be quite suitable in view of the stability and convenience of control after the emergence of perilla.