• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.229-234
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• 2004

The objective of the present study is to conduct model combustion tests for double swirl coaxial injectors to identify their combustion stability characteristics. Gaseous oxygen and mixture of methane and propane have been used as simulant propellants. Two model chambers tuned to the If acoustic resonance mode of a full-scale thrust chamber were manufactured to be used as a combustion cylinder. The main idea of the experiment is that the mixing mechanism is considered as a dominant factor significantly affecting combustion instability in a full-scale thrust chamber. Self-excited dynamic pressure values in a model chamber show different combustion stability zones with respect to a recess number. Upon test results, couplings between combustion conditions and the IT acoustic resonance mode become strengthened with the increase of a recess length.

• Coupled systems mechanics
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• v.2 no.3
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• pp.271-288
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• 2013

In the present study an elastic-plastic strain analysis is carried out for fibrous composites by using numerical modeling. Application of homogeneous transversely-isotropic model was chosen based on problem solution of a square plate with a circular hole under uniaxial tension. The results obtained in this study correspond to the solution of fiber model trial problem, as well as to analytical solution. Further, numerical algorithm and software has been developed, based on simplified theory of small elastic strains for transversely-isotropic bodies, and FEM. The influence of holes and cracks on stress state of complicated configuration transversely-isotropic bodies has been studied. Strain curves and plasticity zones that are formed in vicinity of the concentrators has been provided. Numerical values of effective mechanical parameters calculated for unidirectional composites at different ratios of fiber volume content and matrix. Content volume proportions of fibers and matrix defined for fibrous composite material that enables to behave as elastic-plastic body or as a brittle material. The influences of the fibrous structure on stress concentration in vicinity of holes on boron/aluminum D16, used as an example.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.114-122
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• 1995

In this paper a computational method is presented to solve the plane problem of wave propagation in linear-elastic plate with zones of different materials. An existing numerical scheme of bicharacteristics for rectangular plate is extended to plates with curvilinear boundaries. In order to show the validity of the employed concept, it is necessary to examine the numerical results whether they reproduce the well-known physical phenomena of stress waves. It seems also desirable to make a comparison between the numerical results and appropriate experimental results for plates with curvilinear boundaries. Also studied are the focusing phenomena induced by reflection and refraction at curved outer boundaries and material interfaces.

• Journal of Korea Multimedia Society
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• v.22 no.6
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• pp.729-737
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• 2019

This study defined the animation space as the concept of map based on the space of Joseph Campbell's heroic narrative. The space in which the animated character exists is an image symbolic language that reflects the inner and outer growth stages of the hero. I focused on the spatiality that plays the role of the power to lead the narrative and examined the meaning as the mediator that leads the heroic narrative. First, 6 spatial variables were derived by observing 'Hero's Journey 'which is used as a basis of US commercial animation scenario. Second, spatial variables are defined as 64 zones and proposed as 'Spatial Map Model of the Hero's Journey' (SMMH). Third, the character space of was applied to 'SMMH', and the change of space utilization rate and spatiality and the narrative meaning were analyzed. This study extended the narrative of animation space which was not actively studied to map concept. It is possible to provide a different viewpoint in animation production and research.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1250-1258
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• 2021

In this paper, the mechanical performance of cracked surface-coated Zircaloy cladding, which has different coating materials, coating thicknesses and initial crack lengths, has been investigated. By analyzing the stress field near the crack tip, the safety zone range of initial crack length has been decided. In order to determine whether the crack can propagate along the radial (r) or axial (z) directions, the energy release rate has been calculated. By comparing the energy release rate with fracture toughness of materials, we can divide the initial crack lengths into three zones: safety zone, discussion zone and danger zone. The results show that Cr is suitable coating material for the cladding with a thin coating while Fe-Cr-Al have a better fracture mechanical performance in the cladding with thick coating. The Si-coated and SiC-coated claddings are suitable for reactors with low power fuel elements. Conclusions in this paper can provide reference and guidance for the cladding design of nuclear fuel elements.

• Animal Systematics, Evolution and Diversity
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• v.40 no.1
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• pp.79-87
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• 2024

A taxonomic examination of hydroids collected from the subtidal zones of Ulleungdo and Dokdo located in the East Sea of Korea from 2017 to 2023 was conducted. Through this study, Antennella aurantia n. sp., a new species belonging to the family Halopterididae, was newly added to the hydrozoan fauna of Korea. This new species is clearly distinguished from similar species by the different morphology and size of the hydrothecae, lateral nematothecae, and gonothecae. By comparing the 16S rRNA sequence with 7 recorded species within the Antennella, the interspecific genetic distance to the new species was 8.2-28.9%, which is very high compared to the intraspecific variation of 0.0%, showing that it was clearly distinguished from other species. As a result of this study, a total of 4 Antennella species are reported in the hydrozoan fauna of Korea.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.4
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• pp.16-31
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• 2007

This study is aimed at classifying different types of parks in Gwang-Ju city and providing efficient Planning and guidelines to satisfy the needs of park users. The first stage of this study was accomplished by site surveys of neighborhood parks in Gwang-Ju where park types, locations, neighboring conditions, park layout, and other physical environments were surveyed for the specific status of parks. With those basic data, urban neighborhood park types were classified into different categories: 1) urban neighborhood parks; 2) riverside neighborhood parks; and 3) natural(mountain side) neighborhood parks. For the second stage of this study, behavior patterns and satisfaction were investigated to provide empirical data on the relationship between the physical environment and human behavior. The main findings of this study can be summarized as follows: 1. The highest level of satisfaction for the users of urban neighborhood parks in Gwang-Ju city is the accessibility of the parks which are small but located in neighborhoods, The users tend to visit the nearby parks regardless of size. 2. The users have relatively high levels of satisfaction for urban neighborhood parks which have a lot of green zones or park facilities. Therefore, the park planner should consider the natural environment in the park area and should reconsider the type of park in the planning process. 3. The different types of urban neighborhood parks in Gwang-Ju city do not affect the level of satisfaction and the motivation of park visits. However, the accessibility of the parks is the most important factors of users' satisfaction regardless of the type of the park. 4. The level of user satisfaction for all of the urban neighborhood parks in Gwang-Ju city indicates that the users have a relatively low level of satisfaction. Especially, 26.2% of the users have a high level of dissatisfaction. The new parks, which have recently been developed, have a higher level of satisfaction than the old parks which have a lack of facilities, insufficient maintenance, and poor management planning in the park. 5. As a result of factor analysis, all city neighborhood parks showed a similar tendency with urban type parks, but showed a tendency that was different from the other park types.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.121-129
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• 1987

Indonesian varieties were compared with Korean varieties on three different sowing times, each of which had three different nursery periods, at Suwon, Korea (126$^{\circ}$ 19'E and 37$^{\circ}$ 16'S). Indica-type varieties with exception of late-maturing ones had heading regardless of sowing time and nursery period. As the Korean varieties com-pared with those, the earlier sowing plots with shorter period of nursery gave better result in yields and yield components.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.1-14
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• 2012

A river is defined as the watercourse flowing through its channel, and the mapping tasks of a river plays an important role for the research on the topographic changes in the riparian zones and the research on the monitoring of flooding in its floodplain. However, the utilization of the ground surveying technologies is not efficient for the mapping tasks of a river due to the irregular surfaces of the riparian zones and the dynamic changes of water level of a river. Recently, the spatial information data sets are widely used for the coastal mapping tasks due to the acquisition of the topographic information without human accessibility. In this research, we tried to extract a river from the RapidEye imagery by using the ISODATA(Iterative Self_Organizing Data Analysis) classification algorithm with the two different parameters(NIR (Near Infra-Red) band and NDVI(Normalized Difference Vegetation Index)). First, the two different images(the NIR band image and the NDVI image) were generated from the RapidEye imagery. Second, the ISODATA algorithm were applied to each image and each river was generated in each image through the post-processing steps. River boundaries were also extracted from each classified image using the Sobel edge detection algorithm. Ground truths determined by the experienced expert are used for the assessment of the accuracy of an each generated river. Statistical results show that the extracted river using the NIR band has higher accuracies than the extracted river using the NDVI.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.574-584
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• 1997

Benthic marine algae of Shinjido located on the southern coast of Korea have been investigated to know the floristic composition and community structure. The study was conducted from the intertidal to subtidal zones at two different locations (Kangdok and Donggori) using a line transect method from January to October, 1994. A total of 120 species of marine algae were identified, and they includes 15 green algae, 31 brown algae and 74 red algae. Of these, 87 and 104 species of marine algae occurred at Kangdok and Donggori, respectively. Algal vegetations were divided into three different zonations: the upper, the middle and the lower zones. The representative species are Enteromorpha compressa, Ulva pertusa, Porphyra suborbiculata, lshige okamurae in the upper zone; Hizikia fusiformis, Sargassum thunbergii, Gigatina intermedia, Corallina pilulifera in the middle zone; Pachymeniopsis elliptica, Gelidium amansii, Sargassum horneri in the lower zone. In terms of biomass the dominant species were U. pertusa, I. okamurae, H. fusiformis, C. thunbergii, C. pilulifera, C. amansii, C. tenella. The flora could be classified into six functional form groups such as the coarsely branched form $(36.7\%)$ the filamentous form $(27.5\%)$, the sheet form $(15.8\%)$, the thick leathery form $(10.0\%)$, the jointed calcarious form $(5.0\%)$ and the crustose form $(5.0\%)$.