• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.769-777
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• 2021

Purpose: Earthquake disasters are frequently occur unpredictable situations due to various variables and unexpected situations. As a result, the work process itself is not uniform, making it difficult for public officials in the disaster safety department to familiarize themselves with the earthquake field manual. This paper is specifically and accurately grasp the current work situation conducted by the Disaster and Safety Countermeasures Headquarters of the Gyeongsangbuk-do Office and present a plan for designing serious game scenarios necessary for field manual learning. Method: In this study, scenarios were designed based on the GBS(Goal Based Scenario) model, and in the process of assigning missions and roles based on the Gyeongsangbuk-do earthquake field manual, public officials related to earthquakes were able to acquire knowledge and skills to solve practical tasks. Result: Scenario data of the proposed technique was implemented as a systematic procedure by processing various earthquake-related information into logical data and simplifying and abstracting it for game expression for earthquake situation training. Conclusion: In the event of an earthquake due to learning through serious games, related public officials of Gyeongsangbuk-do provincial are expected to be able to respond quickly to various earthquake disasters.

• Economic and Environmental Geology
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• v.30 no.3
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• pp.249-262
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• 1997

The Sr and Nd isotopic compositions of two foliated granitic plutons located in the Chonju and Sunchang area were determined in order to reconfirm the intrusion ages of granitoids and to study the sources of granitic magmas. The best defined Rb-Sr isochron for the whole rock samples of the Chonju foliated granite (CFGR) give an age of $284{\pm}12Ma$, suggesting early Permian intrusion age. In contrast, the whole rock Rb-Sr data of the Sunchang foliated granite (SFGR) scatter widely on the isochron diagram with very little variation in the $^{87}Rb/^{86}Sr$ ratios and, therefore, yield no reliable age information. Futhermore they show the concordance of mineral and whole rock Rb-Sr isochron and divide into two linear groups with roughly the same slopes and significantly different $^{87}Sr/^{86}Sr$ ratios, indicating some kind of Rb-Sr distortion in whole rock scale and a difference in source material and/or magmatic evolution between two subsets. The reconstructed isochrons of 243 Ma, which was defined from the proposed data by the omission of one sample point with significantly higher $^{87}Rb/^{86}Sr$ ratio than the others, and 252 Ma, from the combined data of it and some of this study, strongly suggest the possibility that the SFGR was intruded appreciably earlier than had previously been proposed, although the reliability of these ages still questionable owing to high scatter of data points and, therefore, further study is necessary. All mineral isochrons for the investigated granites show the Jurassic to early Cretaceous thermal episode ranging from 160 Ma to 120 Ma Their corresponding initial $^{87}Sr/^{86}Sr$ ratios correlate well with their whole rock data, indicating that the mineral Rb-Sr system of the investigated granites was redistributed by the postmagmatic thermal event during Jurassic to early Cretaceous. The initial ${\varepsilon}Sr$ values for the CFGR (64.27 to 94.81) tend to be significantly lower than those for the SFGR (125.43 to 167.09). Thus it is likely that there is a marked difference in the magma source characteristics between the CFGR and the SFGR, although the possibility of an isotopic resetting event giving rise to a high apparent initial ${\varepsilon}Sr$ in the SFGR can not be ruled out. In contrast to ${\varepsilon}Sr$, both batholiths show a highly resticted and negative values of initial ${\varepsilon}Nd$, which is -14.73 to -19.53 with an average $-16.13{\pm}1.47$ in the CFGR and -14.78 to -18.59 with an average $-17.17{\pm}1.01$ in the SFGR. The highly negative initial ${\varepsilon}Nd$ values in the investigated granitoids strongly suggest that large amounts of recycled old continental components have taken part in their evolution. Furthermore, this highly resticted variation in ${\varepsilon}Nd$ is significant because it requires that the old crustal source material, from which the granitoid-producing melts were generated, should have a reasonably uniform Nd isotopic composition and also quit similar age. Calculated T2DM model ages give an average of $1.83{\pm}0.25Ga$ for CFGR and $1.96{\pm}0.19Ga$ for SFGR, suggesting the importance of a mid-Proterozoic episode for the genesis of two foliated granites. Although it is not possible to determine precisely the source rock compositions for the investigated foliatic granites, the Sr-Nd isotopic evidences indicate that midcrustal or less probably, a lower crustal granulitic source could be the most likely candidate.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.629-641
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• 2021

In this study, a two-dimensional numerical model (Nays2DH) was applied to analyze the process of morphological changes in the river channel bed depending on the changes in the amount of flooding after fully opening the Sejong weir, which was constructed upstream of the Geum River. For this, numerical simulations were performed by assuming the flow conditions, such as a non-uniform flow (NF), unsteady flows (single flood event, SF), and a continuous flood event (CF). Here, in the cases of the SF and CF, the normalized hydrograph was calculated from real flood events, and then the hydrograph was reconfigured by the peak flow discharge according to the scenario, and then it was employed as the flow discharge at the upstream boundary condition. In this study, to quantitatively evaluate the morphological changes, we analyzed the time changes in the bed deformation the bed relief index (BRI), and we compared the aerial photographs of the study area and the numerical simulation results. As simulation results of the NF, when the steady flow discharge increases, the ratio of lower width to depth decreases and the speed of bar migration increases. The BRI initially increases, but the amount of change decreased with time. In addition, when the steady flow discharge increases, the BRI increased. In the case of SF, the speed of bar migration decreased with the change of the flow discharge. In terms of the morphological response to the peak flood discharge, the time lag also indicated. In other words, in the SF, the change of channel bed indicates a phase lag with respect to the hydraulic condition. In the result of numerical simulation of CF, the speed of bar migration depending on the peak flood discharges decreased exponentially despite the repeated flood occurrences. In addition, as in the result of SF, the phase lag indicated, and the speed of bar migration decreased exponentially. The BRI increased with time changes, but the rate of increase in the BRI was modest despite the continuous peak flooding. Through this study, the morphological changes based on the hydrological characteristics of the river were analyzed numerically, and the methodology suggested that a quantitative prediction for the river bed change according to the flow characteristic can be applied to the field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.1
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• pp.4296-4311
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• 1977

This study was conducted to derive an Instantaneous Unit Hydrograph for the accurate and reliable unitgraph which can be used to the estimation and control of flood for the development of agricultural water resources and rational design of hydraulic structures. Eight small watersheds were selected as studying basins from Han, Geum, Nakdong, Yeongsan and Inchon River systems which may be considered as a main river systems in Korea. The area of small watersheds are within the range of 85 to 470$\textrm{km}^2$. It is to derive an accurate Instantaneous Unit Hydrograph under the condition of having a short duration of heavy rain and uniform rainfall intensity with the basic and reliable data of rainfall records, pluviographs, records of river stages and of the main river systems mentioned above. Investigation was carried out for the relations between measurable unitgraph and watershed characteristics such as watershed area, A, river length L, and centroid distance of the watershed area, Lca. Especially, this study laid emphasis on the derivation and application of Instantaneous Unit Hydrograph (IUH) by applying Nash's conceptual model and by using an electronic computer. I U H by Nash's conceptual model and I U H by flood routing which can be applied to the ungaged small watersheds were derived and compared with each other to the observed unitgraph. 1 U H for each small watersheds can be solved by using an electronic computer. The results summarized for these studies are as follows; 1. Distribution of uniform rainfall intensity appears in the analysis for the temporal rainfall pattern of selected heavy rainfall event. 2. Mean value of recession constants, Kl, is 0.931 in all watersheds observed. 3. Time to peak discharge, Tp, occurs at the position of 0.02 Tb, base length of hlrdrograph with an indication of lower value than that in larger watersheds. 4. Peak discharge, Qp, in relation to the watershed area, A, and effective rainfall, R, is found to be {{{{ { Q}_{ p} = { 0.895} over { { A}^{0.145 } } }}}} AR having high significance of correlation coefficient, 0.927, between peak discharge, Qp, and effective rainfall, R. Design chart for the peak discharge (refer to Fig. 15) with watershed area and effective rainfall was established by the author. 5. The mean slopes of main streams within the range of 1.46 meters per kilometer to 13.6 meter per kilometer. These indicate higher slopes in the small watersheds than those in larger watersheds. Lengths of main streams are within the range of 9.4 kilometer to 41.75 kilometer, which can be regarded as a short distance. It is remarkable thing that the time of flood concentration was more rapid in the small watersheds than that in the other larger watersheds. 6. Length of main stream, L, in relation to the watershed area, A, is found to be L=2.044A0.48 having a high significance of correlation coefficient, 0.968. 7. Watershed lag, Lg, in hrs in relation to the watershed area, A, and length of main stream, L, was derived as Lg=3.228 A0.904 L-1.293 with a high significance. On the other hand, It was found that watershed lag, Lg, could also be expressed as {{{{Lg=0.247 { ( { LLca} over { SQRT { S} } )}^{ 0.604} }}}} in connection with the product of main stream length and the centroid length of the basin of the watershed area, LLca which could be expressed as a measure of the shape and the size of the watershed with the slopes except watershed area, A. But the latter showed a lower correlation than that of the former in the significance test. Therefore, it can be concluded that watershed lag, Lg, is more closely related with the such watersheds characteristics as watershed area and length of main stream in the small watersheds. Empirical formula for the peak discharge per unit area, qp, ㎥/sec/$\textrm{km}^2$, was derived as qp=10-0.389-0.0424Lg with a high significance, r=0.91. This indicates that the peak discharge per unit area of the unitgraph is in inverse proportion to the watershed lag time. 8. The base length of the unitgraph, Tb, in connection with the watershed lag, Lg, was extra.essed as {{{{ { T}_{ b} =1.14+0.564( { Lg} over {24 } )}}}} which has defined with a high significance. 9. For the derivation of IUH by applying linear conceptual model, the storage constant, K, with the length of main stream, L, and slopes, S, was adopted as {{{{K=0.1197( {L } over { SQRT {S } } )}}}} with a highly significant correlation coefficient, 0.90. Gamma function argument, N, derived with such watershed characteristics as watershed area, A, river length, L, centroid distance of the basin of the watershed area, Lca, and slopes, S, was found to be N=49.2 A1.481L-2.202 Lca-1.297 S-0.112 with a high significance having the F value, 4.83, through analysis of variance. 10. According to the linear conceptual model, Formular established in relation to the time distribution, Peak discharge and time to peak discharge for instantaneous Unit Hydrograph when unit effective rainfall of unitgraph and dimension of watershed area are applied as 10mm, and $\textrm{km}^2$ respectively are as follows; Time distribution of IUH {{{{u(0, t)= { 2.78A} over {K GAMMA (N) } { e}^{-t/k } { (t.K)}^{N-1 } }}}} (㎥/sec) Peak discharge of IUH {{{{ {u(0, t) }_{max } = { 2.78A} over {K GAMMA (N) } { e}^{-(N-1) } { (N-1)}^{N-1 } }}}} (㎥/sec) Time to peak discharge of IUH tp=(N-1)K (hrs) 11. Through mathematical analysis in the recession curve of Hydrograph, It was confirmed that empirical formula of Gamma function argument, N, had connection with recession constant, Kl, peak discharge, QP, and time to peak discharge, tp, as {{{{{ K'} over { { t}_{ p} } = { 1} over {N-1 } - { ln { t} over { { t}_{p } } } over {ln { Q} over { { Q}_{p } } } }}}} where {{{{K'= { 1} over { { lnK}_{1 } } }}}} 12. Linking the two, empirical formulars for storage constant, K, and Gamma function argument, N, into closer relations with each other, derivation of unit hydrograph for the ungaged small watersheds can be established by having formulars for the time distribution and peak discharge of IUH as follows. Time distribution of IUH u(0, t)=23.2 A L-1S1/2 F(N, K, t) (㎥/sec) where {{{{F(N, K, t)= { { e}^{-t/k } { (t/K)}^{N-1 } } over { GAMMA (N) } }}}} Peak discharge of IUH) u(0, t)max=23.2 A L-1S1/2 F(N) (㎥/sec) where {{{{F(N)= { { e}^{-(N-1) } { (N-1)}^{N-1 } } over { GAMMA (N) } }}}} 13. The base length of the Time-Area Diagram for the IUH was given by {{{{C=0.778 { ( { LLca} over { SQRT { S} } )}^{0.423 } }}}} with correlation coefficient, 0.85, which has an indication of the relations to the length of main stream, L, centroid distance of the basin of the watershed area, Lca, and slopes, S. 14. Relative errors in the peak discharge of the IUH by using linear conceptual model and IUH by routing showed to be 2.5 and 16.9 percent respectively to the peak of observed unitgraph. Therefore, it confirmed that the accuracy of IUH using linear conceptual model was approaching more closely to the observed unitgraph than that of the flood routing in the small watersheds.

• Journal of the Korean earth science society
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• v.39 no.3
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• pp.241-249
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• 2018

As the international trade increases, vessel traffics around the Korean Peninsula are also increasing. Maritime accidents hence take place more frequently in the southern coast of Korea where many big and small ports are located. Accidents involving ship collision and sinking result in a substantial human and material damage as well as the marine environmental pollution. Therefore, it is necessary to locate the ships quickly when such accidents occur. In this study, we suggest a new ship detection index by comparing and analyzing the reflectivity of each channel of the Korea MultiPurpose SATellite-2 (KOMPSAT-2) images of the area around the Gwangyang Bay. A threshold value of 0.1 is set based on a histogram analysis, and all vessels are detected when compared with RGB composite images. After selecting a relatively large ship as a representative sample, the distribution of spatial reflectivity around the ship is studied. Uniform shadows are detected on the northwest side of the vessel. This indicates that the sun is in the southeast, the azimuth of the actual satellite image is $144.80^{\circ}$, and the azimuth angle of the sun can be estimated using the shadow position. The reflectivity of the shadows is 0.005 lower than the surrounding sea and ship. The shadow height varies with the position of the bow and the stern, perhaps due to the relative heights of the ship deck and the structure. The results of this study can help search technology for missing vessels using optical satellite images in the event of a marine accident around the Korean Peninsula.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.493-502
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• 2012

Objectives: The purpose of this study is to investigate the mass concentration of nanoparticles and understand the characteristics of elements of heavy metal concentrations within nanoparticles in the air using Micro-Orifice Uniform Deposit Impactor Model-110 (MOUDI-110), based on indoor and outdoor air. Methods: This Study sampled nanoparticles using MOUDI-110 indoors (office) and outdoors at S University in Asan, Korea in order to reveal the concentration of nanoparticles in the air. Sampling continued for nine months (10 times indoors and 14 times outdoors) from March to November 2010. Mass concentrations of nanoparticle and concentrations of heavy metals (Al, Mn, Zn, Ni, Cu, Cr, Pb) were analyzed. Results: Indoors, geometric mean concentration of nanoparticles ranged in size from 0.056 ${\mu}m$ to 0.10 ${\mu}m$ and those of 0.056 ${\mu}m$ or less recorded 0.929 ${\mu}g/m^3$ and 1.002 ${\mu}g/m^3$, respectively. On the other hand, the levels were lower outdoors with 0.819 ${\mu}g/m^3$ and 0.597 ${\mu}g/m^3$. Mann-Whitney U tests showed that the difference between the indoors and the outdoors was statistically meaningful in terms of particles of 0.056 ${\mu}m$ or less (p<0.05) in size. These results are possibly influenced by the use of printers and duplicators as the factor that increased the concentration of nanoparticles. In seasonal concentration distribution, the level was higher during the summer compared to in the autumn. Those of 0.056 ${\mu}m$ or less in size presented a statistically meaningful difference during the summer (p<0.05). These results may be influenced by photochemical event as the factor that makes the levels high. Regarding zinc, among the other heavy metals, the fine particles ranged in size from 0.056 ${\mu}m$ to 0.10 ${\mu}m$ and those of 0.056 ${\mu}m$ or less recorded 1.699 $ng/m^3$ and 1.189 $ng/m^3$ in the outdoors. In the indoors, the levels were lower, with 0.745 $ng/m^3$ and 0.617 $ng/m^3$. Cr and Ni at the size of 0.056 ${\mu}m$ or less, both of which have been known to pose severe health effects, recorded higher concentrations indoors with 0.736 $ng/m^3$ and 0.177 $ng/m^3$, compared to 0.444 $ng/m^3$ and 0.091 $ng/m^3$ outdoors. By season, Zn, Ni, Cu and Pb posted a high level of indoor concentration during the fall. As for Cr, the level of concentration indoors was higher than outdoors both during the summer and the autumn. Conclusion: This study indicates the result of an examination of nano-sized particles and heavy metal concentrations. It will provide useful data for the determination of basic nanoparticle standards in the future.