• Journal of Korea Water Resources Association
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• v.47 no.11
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• pp.1077-1086
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• 2014

The flood wave generated due to dam break is affected by initial depth upstream since it is related with hydraulic characteristics propagating downstream, and flow resistance stress has influence on the celerity, travel distance, and approaching depth of shock wave in implementing numerical simulation. In this study, a shallow water flow model employing SU/PG scheme was developed and verified by analytic solutions; propagation characteristics of dam break according to flow resistance and initial depth were analyzed. When bottom frictional stress was applied, the flow depth was relatively higher while the travel distance of shock wave was shorter. In the case of Coulomb stress, the flow velocity behind the location of dam break became lower compared with other cases, and showed values between no stress and turbulent stress at the reach of shock wave. The value of Froude number obtained by no frictional stress at the discontinuous boundary was the closest to 1.0 regardless of initial depth. The adaption of Coulomb stress gave more appropriate results compared with turbulent stress at low initial depth. However, as the initial depth became increased, the dominance of flow resistance terms was weakened and the opposite result was observed.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.323-336
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• 2019

The Mesozoic activity on the Korean Peninsula is mainly represented by the Triassic post-collisional, Jurassic orogenic, and Cretaceous post-orogenic igneous activities. The diversity of mineralization by each geological period came from various geothermal systems derived from the geochemical characteristics of magma with different emplacement depth. The Cretaceous metallic mineralization has been carried out over a wide range of time periods from ca. 115 to 45 Ma (main stage; ca. 100 to 60 Ma) related to post-orogenic igneous activity, and spatial distribution patterns of most metal deposits are concentrated along small granitic stocks. The late Cretaceous metal deposits in the Gyeonggi and Yeongnam massifs are generally distributed along the boundary among the Gongju-Eumseong fault system and the Yeongdong-Gwangju fault system and the Gyeongsang Basin, most of them are in the form of a distal epithermal~mesothermal Au-Ag vein or a transitional mesothermal Zn-Pb-Cu vein. On the other hand, diverse metal commodities in the Taebaeg Basin, the Okcheon metamorphic belt and the Gyeongsang Basin are produced from various deposit types such as skarn, carbonate-replacement, vein, porphyry, breccia pipe, and Carlin type. In the late Cretaceous metallic mineralization, various mineral deposits and commodities were induced not only by the pathway of the hydrothermal solution, but also by the diversity of precipitation environment in the proximity difference of the granitic rocks. The diversity of these types of Cretaceous deposits is fundamentally dependent on the geochemical characteristics such as degree of differentiation and oxidation state of related igneous rocks, and ore-forming fluids generally exhibit the evolutionary characteristics of intermediate- to low-sulfur hydrothermal fluids.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.4
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• pp.168-178
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• 2021

Numerical simulations were implemented to look into the modified seabed topography due to the presence of breakwaters of varying reflection characteristics. The numerical model was composed of OlaFlow, an OpenFoam-based tool box, and a physics-based morphology model [Seoul Foam]. In doing so, the interaction between the seabed, which undergoes deformation due to siltation and scouring, and the incoming waves was described using Dynamic Mesh. The rubble-mound, vertical, and curved slit caisson breakwaters with varying reflection characteristics resulted in standing waves that differ from each other, shown to have a significant influence on the seabed topography. These results are in line with Nielsen's study (1993) that sands saltated under the surface nodes of standing waves, where the near-bed velocities are most substantial, convected toward the surface antinodes by boundary-layer drift. Moreover, the crest of sand waves was formed under the surface antinodes of standing waves, and the trough of sand waves was formed under the surface antinodes. In addition, sand wave amplitude reaches its peak in the curved slit caisson with a significant reflection coefficient, and the saltation of many grains of sand would cause this phenomenon due to the increased near-bed velocity under the nodes when the reflection coefficient is getting large.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.88-94
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• 2022

The vibration mode measurement test measures the natural vibration characteristics of the target specimen. The measured natural mode characteristics are compared with the numerical analysis result to verify the reliability of the numerical analysis. If necessary, it is used to supplement the numerical analysis model of the specimen used for the dynamic characteristic analysis. In this paper, the natural frequency and natural mode of the external fuel tank are respectively obtained through the vibration mode measurement test and the numerical analysis, using the finite element model. The results are compared to verify the reliability of the numerical analysis model of the external fuel tank to apply to the entire aircraft model. To measure the vibration mode of the test specimen, a bungee cord was used, to simulate the free boundary condition for the test specimen. And, 3-axis accelerometers were installed on the test specimen. The response characteristics of the test specimen were measured, by excitation with an impact hammer. As a result of the test, after performing the frequency response analysis on the response acceleration, the natural frequency of the test specimen and its vibration mode were confirmed. The reliability of the numerical analysis model was verified by comparing the frequency and vibration mode, obtained through the test and the numerical analysis.

• Strategy21
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• s.31
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• pp.27-56
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• 2013

The United Nations Command (UNC) and the communist North failed to reach an agreement on where the maritime demarcation line should be drawn in the process of signing a truce after the Korean War because of the starkly different positions on the boundary of their territorial waters. As a result, the Armistice Treaty was signed on July 1953 without clarification about the maritime border. In the following month, Commander of the UNC unilaterally declared the Northern Limit Line (NLL) as a complementing measure to the Armistice. Referring to this, North Korea and its followers in South Korea wrongfully argue that the NLL is a "ghost line" that was established not based on the international law. However, one should note that the waters south of the NLL has always been under South Korea's jurisdiction since Korea's independence from Japan on August 15, 1945. There is no need to ask North Korea's approval for declaring the territorial waters that had already been under our sovereign jurisdiction. We do not need North Korea's approval just as we do not need Japan's approval with regard to our sovereign right over Dokdo. The legal status of the NLL may be explained with the following three characteristics. First, the NLL is a de facto maritime borderline that defines the territorial waters under the respective jurisdiction of the two divided countries. Second, the NLL in the West Sea also serves as a de facto military demarcation line at sea that can be likened to the border on the ground. Third, as a contacting line where the sea areas controlled by the two Koreas meet, the NLL is a maritime non-aggression line that was established on the legal basis of the 'acquiescence' element stipulated by the Inter-Korea Basic Agreement (article 11) and the Supplement on the Non-aggression principle (article 10). Particularly from the perspective of the domestic law, the NLL should be understood as a boundary defining areas controlled by temporarily divided states (not two different states) because the problem exists between a legitimate central government (South Korea) and an anti-government group (North Korea). In this sense, the NLL problem should be viewed not in terms of territorial preservation or expansion. Rather, it should be understood as a matter of national identity related to territorial sovereignty and national pride. North Korea's continuous efforts to problematize the NLL may be part of its strategy to nullify the Armistice Treaty. In other words, North Korea tries to take away the basis of the NLL by abrogating the Armistice Treaty and creating a condition in which the United Nations Command can be dissolved. By doing so, North Korea may be able to start the process for the peace treaty with the United States and reestablish a maritime line of its interest. So, North Korea's rationale behind making the NLL a disputed line is to deny the effectiveness of the NLL and ask for the establishment of a new legal boundary. Such an effort should be understood as part of a strategy to make the NLL question a political and military dispute (the similar motivation can be found in Japan's effort to make Dokdo a disputed Island). Therefore, the South Korean government should not accommodate such hidden intentions and strategy of North Korea. The NLL has been the de facto maritime border (that defines our territorial waters) and military demarcation line at sea that we have defended with a lot of sacrifice for the last sixty years. This is the line that our government and the military must defend in the future as we have done so far. Our commitment to the defense of the NLL is not only a matter of national policy protecting territorial sovereignty and jurisdiction; it is also our responsibility for those who were fallen while defending the North-Western Islands and the NLL.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.E
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• pp.332-342
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• 1994

Hierarchical cluster and factor analyses were used to identify various influences on free tropospheric air samples at Mauna Loa Observatory in Hawaii during MLOPEX. The cluster analysis separated thirteen chemical and meteorological variables into three characteristic groups (1)clean air, (2)anthropogenically influenced air, (3)marine and volcanic influenced air. The cluster analysis results compared well with those of factor analysis. Six independent components were identified in factor analysis. We have related these components to (1)volcano influenced air, (2)stratosphere-like air, (3)boundary-layer air with recent anthropogenic influence, (4)photochemical haze, (5)marine boundary- layer air, and (6)modified marine tropospheric air. Excluding local influence, we could calculate the nighttime free tropospheric values for $O_3$(41$\pm$10 ppbv), HN $O_3$(94$\pm$45 pptv), N $O_3$$^{[-10]}$ (16$\pm$10 ppbv), S $O_4$$^{[-10]}$ (60$\pm$0 pptv), N $H_4$$^{＋}$(71$\pm$6 pptv), N $a^{＋}$(5$\pm$1 pptv), PAN(13$\pm$9 pptv), MeN $O_3$(3.5$\pm$1.5 pptv), 2-butyl N $O_3$(0.6$\pm$0.1 pptv), $H_2O$$_2$(1015$\pm$44 pptv), $C_2$C $l_4$(3.3$\pm$0.1 pptv), condensation nuclei(249$\pm$13c $m^{-3}$), and dew point(-8.5$\pm$5.3$^{\circ}C$) during this experiment..

• Journal of Korean Academy of Fundamentals of Nursing
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• v.9 no.1
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• pp.113-122
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• 2002

Purpose: The purpose of this study was to identify characteristics of serum ferrum, TIBC and ferritin's circadian rhythm in normal adults and to prepare a standard to determine the examination material extraction time. Method: Nine women and ten men made up the convenience sample for this study they were from the staff of D university hospital and students in D medical School located in K city who met the qualifications for inclusion in the sample. The value of serum ferrum, TIBC and circadian rhythm were calculated as follows : First. each variable's amplitude. the acrophase and average were measured for a 24 hour cycle using the cosinor method, and then each person's rhythm was analyzed. Results: There were significant serum iron circadian rhythm for both men and women (p<.05). For the men, mesor was $105.91{\mu}g/dl$. amplitude was $29.52{\mu}g/dl$, and the acrophase was 9.76 hour. For the women, mesor was $108.17{\mu}g/dl$, amplitude was $28.09{\mu}g/dl$, and the acrophase was 11.42 hour The rhythm change of TIBC was only significant for the women (p<.05), mesor was 383.39mg/dl, amplitude was 60.29mg/dl. and the acrophase was 14.93hour. As for the circadian rhythm of the ferritin, there are no diurnal variation in either sex, men were between 134.0ng/ml and 137.4ng/ml, and women, between 29.1ng/ml and 30.1ng/ml. Conclusion: To help diagnose the boundary line between normal or deficiency in iron, measurement should be carried out at a fixed time in the morning and evening, or a more proper time would be in the afternoon at the time when the width of amplitude is the least.

• Fire Science and Engineering
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• v.27 no.2
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• pp.80-88
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• 2013

The validation of Fire Dynamics Simulator (FDS) was conducted for the under-ventilated fire in well-confined multi-compartments representative of nuclear power plant. Numerical results were compared with experimental data obtained by the OECD/NEA PRISME project. The effects of the numerical boundary conditions (B.C.) in ventilated system and the flame suppression model applied within FDS on the thermal and chemical environments inside the compartment were discussed in details. It was found that numerical B.C. on the vent flow resulting from over-pressure at ignition and under-pressure at extinction should be considered carefully in order to predict accurately the species concentrations rather than temperatures and heat fluxes inside the multi-compartment. The default information of suppression model applied within FDS resulted in artificial phenomena such as flame extinction and re-ignition, and thus the FDS results on the under-ventilated fire showed good agreement with the experimental results as the modified suppression criteria of the fuel used was adopted.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.107-118
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• 2010

The purpose of this study was to set the boundary of the coastal sand dunes and to analyze the change characteristics of land cover types using aerial photographs on Osan and Dongho coastal sand dunes in Yangyang. The boundaries of sand dunes were established using digital soil map, and land cover maps were made for each year using aerial photographs. As results of analysis, both beach and farmland areas have been decreased, since 1974 and forest area was relatively increased due to planting and forest growth. Facilities and bare land have been greatly increased since 1992. Loss of wetland, and beach due to these changes had an impact on the ecosystem destruction of sand dunes.

• Korean Institute of Interior Design Journal
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• v.23 no.6
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• pp.22-32
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• 2014

Development of digital technology, which is individualizing and differentiating the world, makes time and space facilitate multi-layering in the contemporary society. It gives a large influence on the contemporary architecture that inducing the visual and spatial experience. Also, It generates new images through the skin of architecture, which implies the contingent and fluid characteristics. These phenomenon show that various parameters are working on the architectural skin simultaneously. Such complexity make the structure of open space and diversity that are homogenized and synchronized. Like this, the architectural skin implies 'multiplicity': qualitative difference which is enable to change and create new images. This characteristic generates instant images changing variously and semantics constantly by the function of skin as a filter. Also, the architectural skin integrates or relocates of relationships between the various information and elements appearing in contemporary society in order to escape the customary relationship between internal and external. Furthermore, the inside and outside of the mixture as a collection of sense has been recognized as one image. This image of mixture consists of one unified continuous integration and extend the meaning of a fluid interface not just surface of the building. The skin of the contemporary architecture is very technical, so its meaning and role is expanded as a complex that exchange interaction. This means that the skin itself has functional elements of the integrated multiple skin to assist. Also it can form a multi-layered relationship and act as a wide range of interfaces depending on the perception of the observer. Therefore the multiplicity of the architectural skin indicates the importance as a boundary that generate images of new life through the sensory perception and implicit force. And it shows potential as the intermediary to try to communicate.