• Journal of the Korean Geographical Society
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• v.30 no.3
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• pp.207-229
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• 1995

The characteristics of weather and climate in South Korea has great influences on the annual variation pattern and the appearance of the prevailing weather. The purpose of this paper is to induce the quantity of the weather entropy and annual variation pattern using the information theory and the principal component analysis. And author tried to classify the region according to the variation of its space scale, The raw materials used for this study are the daily cloudiness and precipitation during the years 1990-1994 at 69 stations in South Korea. It is divided into four classes of fine, clear, cloudy and rainy. The rcsults of this study can be summarized as follows: 1. Thc characteristics of annual variation pattern of weather entropy can be chiefly divided into five categories and the accumulated contributory rate of these is 73.1%. 2. Annual variation pattern of the first principal component reaches smaller in May, April and September than national average, and becomes greater when the winter comes. This weather entropy's quantity(Rs1) is positive in most area to the western sife of Soback Mountains and negative in most seaside area to the eastern side of Soback Mountains. 3. The characteristics of annual variation pattern of the second principal component shows that the entropy is more smaller in summer than national average and the rest of seasons shows larger, especially in January, May and September. This weather entropy's quantity(Rs2) is positive in most Honam Inland area to the western side of Soback Mountains and negative in most Youngnam Inland area to the eastern side of Soback Mountains. 4. Eight type regions (S1-S11) are classified based on the occurrences of minimum weather entropy in South Korea, and annual variation pattern of weather entropy by principal component analysis may be classified into sixteen type regions (Rs1-Rs9). Putting these things together, South Korea can be classifieed into thirty one type regions (Rs1S7-Rs9S10).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.871-881
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• 2001

In this paper, the effect of soft handoff technique on CDMA cell coverage is analyzed in a lognormally shadowed channel, which uses the Hata propagation model, Also, the rate of increase for the cell coverage is analyzed by calculating the hard and soft handoff margin. When the outage probability is 0.02 and the standard deviation of the received signal is 2.5 dB in a lognormally shadowed channel, the transmit power of the mobile station which is located in the cell boundary is increased by the hard handoff margin of 5.13 dB and by the soft handoff margin of 3.68 dB, respectively. So, the rate of increase for the cell coverage is 1.39 in case of using the soft handoff technique. It is shown that if the (E$\_$b//N$\_$0/)$\_$req/ value is 7 dB, the cell coverage of the CDMA cellular system with soft handoff technique in city area is 3.33 km in case of the 850 MHz frequency and 1.36 km in case of the 1900 MHz frequency. Also, the accurate cell coverage with soft handoff technique is supported that could be serviced by the base-station in CDMA cellular system.

• Investigative Magnetic Resonance Imaging
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• v.11 no.2
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• pp.103-109
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• 2007

To develop an advanced non-linear curve fitting (NLCF) algorithm for performing dynamic susceptibility contrast study of the brain. The first pass effects give rise to spuriously high estimates of $K^{trans}$ for the voxels that represent the large vascular components. An explicit threshold value was used to reject voxels. The blood perfusion and volume estimation were accurately evaluated in the $T2^*$-weighted dynamic contrast enhanced (DCE)-MR images. From each of the recalculated parameters, a perfusion weighted image was outlined by using the modified non-linear curve fitting algorithm. The present study demonstrated an improvement of an estimation of the kinetic parameters from the DCE $T2^*$-weighted magnetic resonance imaging data with using contrast agents.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.409-425
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• 2013

This study presents a prediction of a time-series of the area inundated by effluent from Heavenly Lake caused by ground behavior prior to a volcanic eruption. A GIS-based hydrological algorithm that considers the multi-flow direction of effluent, the absorption and storage capacity of the ground soil, the storage volume of the basin or the depression terrain, was developed. To analyze the propagation pattern, four hypothetical collapse zones on the cheonji ground were set, considering the topographical characteristics and distributions of volcanic rocks at Mt. Baekdu. The results indicate that at 3 hours after collapse, for both scenarios 1 and 2 (collapses of the entire/southern boundary of cheonji), a flood hazard exists for villages in China, but not for those on the North Korean side of the mountain, due to the topographical characteristics of Mt. Baekdu. It is predicted that villages in both North Korea and China would be significantly damaged by flood inundation at 3 hours elapsed time for both scenarios 3 and 4 (collapses on the southern boundary of cheonji and on the southeastern-peak area).

• Economic and Environmental Geology
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• v.35 no.6
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• pp.553-565
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• 2002

Seasonal variations in vertical distributions of metals were investigated in the contaminated paddy soils around Siheung Cu-Pb-Zn and Deokeum Au-Ag mines. Geochemical behavior of metals was also evaluated with respect to redox changes during the cultivation of rice. Two microcosms simulating the rice-growing paddy field were set up in the laboratory. The raw paddy soils from two sites showed differences in mineralogy, metal concentrations and gecochemical parameters, and it is suggested that high proportions of exchangeable fractions in metals may give high dissolution rates at Deokeum. In both microcosms of Siheung and Deokeum, redox differences between surface and subsurface of paddy soils were maintained during the flooded period of 18 weeks. Siheung soil had neutral to alkaline pH conditions, while strongly acidic conditions and high Eh values were found at the surface soil of Deokeum. The concentrations of dissolved Fe and Mn were higher in the subsurface pore waters than in interface and upper waters from both microcosms, indicating reductive dissolution under reducing conditions. On the contrary, dissolved Pb and Zn had high concentrations at the surface under oxidizing conditions. From the Siheung microcosm, release of dissolved metals into upper waters was decreased. presumably by the trap effect of Fe- and Mn-rich layers at the interface. However, in the Deokeum microcosm, significant amounts of Pb and Zn were released into upper water despite the relatively lower contents in raw paddy soil, and seasonal variations in the chemical fractionation of metals were observed between flooded and drained conditions. Under acidic conditions, rice may uptake high amounts of metals from the surface of paddy soils during the flooded periods, and increases of exchangeable phases may also increase the bioavailability of heavy metals in the drained conditions.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.430-439
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• 2006

This paper presents the a measured path-loss characteristics for mobile communications beyond 3G in microcellular residential area and street microcell at 3.4, 5.3, and 6.4 GHz band signals. The residential area is divided into two sections, one of which is composed of fifteen-story appartment buildings. The other section comprises four-story houses. The street microcell is classified line-of-sight(LOS) and nonline-of-sight(NLOS) areas. Both residential areas have standard deviations independent of the residential area classification, whereas the path loss exponents in the apartments is higher than those in area for same frequencies. A two-ray model is applied to analyse the path-loss charateristics in LOS areas. In LOS areas, an empirical breakpoint, whose distance is 6 percent shorter than a theorical breakpoint, is founded. Further, a sudden power level drop occurs at a transition point from LOS region to NLOS area. Path loss exponent is found to be significantly higher for non-LOS region than for LOS region. The power level drop due to corner loss and path-loss exponents both increase as the distance between the transmitter and the corner increases.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.187-197
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• 2010

The paleoseismological study in Korea has begun along the Yangsan fault zone (YFZ) and Ulsan fault zone (UFZ) since 1994. Some evidences related to late Quaternary movement are found at only some part of the YFZ, such as Pyonghae, Yuge, and Eonyang-Tongdosa areas. However, it is found along the most of the UFZ except the northen and southern ends of the fault. The dominant time span of faulting events along the YFZ and UFZ are quite different, and 500 ka to 200 ka and 300 ka to recent time, respectively. The dominant faulting senses of the YFZ and UFZ are right-lateral strike slip and reverse, respectively. These senses correspond well with the focal mechanism of recent occurring earthquakes along these two fault zones. If we evaluate the intensity of the activity of the YFZ from the average slip rate, which is 0.1~0.04 m/ka, it is comparable with the faults of higher C class in Japan. The slip rate of UFZ, which is 0.2~0.06 m/ka, is comparable with the faults of lower B to higher C class. Based on the relationship between maximum displacement and magnitude, the maximum earthquake magnitude is evaluated to be 6.8 and 7.0 in the YFZ and UFZ, respectively. An intensive studies are needed to clarify the problems such as segmentation of faults, return period, and geological evidences related to historical earthquakes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.161-167
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• 2011

In case that the maximum temperature of any surface readily accessible during transport of a spent nuclear fuel (SNF) transport cask exceeds $85^{\circ}C$ in the absence of insolation under the ambient temperature of $38^{\circ}C$, personnel barriers or transport hood shall be used to prevent people from casual contact with the transport cask surface. Usually the air temperature within the hood and the hood surface temperature are calculated and further utilized as boundary conditions(free stream temperature and external radiation temperature) for thermal evaluation under normal conditions of transport. In this study, these temperatures are derived using the analytical method based on the heat transfer mechanism around the transport cask under transport hood assuming the thermal equilibrium. By comparing the analytical solutions with the results from the detailed calculations with CFD-computer-code FLUENT 12.1 it is verified that the analytical method is still efficient tool to estimate the temperatures and these temperatures can be further used as boundary conditions for thermal evaluation under normal conditions of transport.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.386-393
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• 2018

The Korean military supplies industry tends to become limited in terms of its development to specific areas in line with strategic promotion policies of the local private direct industrial site. However, the relation between base and small cluster is getting lower of the local industrial site. In this study, information related to authorized test reports for munitions was collected through the military quality information system and subjected to social network analysis(SNA). SNA was performed through the relationships among defense quality assurance agencies, test institutions, contracts and cooperative firms through UCINET's Two-Mode Network. In the field of weapon systems, the median technology industry, and the test analysis dependent are high in Seoul, so the analysis revealed that strengthening the infrastructure for test analysis is needed. Also, it was deemed necessary for government-driven political support. Besides, the field support system was efficiently utilizing a relatively local test analysis. It was analyzed that they are overcoming the regional boundaries of small clusters by strategically changing their contract and cooperative firms' status. The research found some spatial inconsistencies between base and small clusters in the military supplies industry, and it was judged that a political suggestion was needed.

• Journal of the Korean association of regional geographers
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• v.13 no.5
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• pp.576-594
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• 2007

The purpose of this study is to derive policy implications in allocating day care centers for the elderly with more efficiency and/or equity by calculating and analysing the accessibility scores of individual dongs to day care centers for the elderly in Seoul using GIS spatial analysis techniques. The study finds that the spatial distribution of the centers does not respond to the distribution of the potential users very well and that dongs in Gangseo-gu and Songpa-gu at the outskirt of Seoul has the lowest level of accessibility. The findings of the study has policy implications in the management of day care centers for the elderly. First, in order to improve the accessibility of the elderly to the centers, an increase in the number and the capacity of the centers needs to be made especially in areas with lower level of services provided. Second, if policy decision is made in the way to increase the capacity of the existing centers rather than to increase the number of centers due to, for example, the budget limit, capacity expansion needs to be made in the centers with higher proximity in order for more elderly people to use the centers more frequently with easy access. Finally, this type of accessibility analysis techniques needs to be used to allocate, expand, and evaluate other types of care facilities for the elderly and social welfare facilities in order to preserve the welfare right of the users of the facility who usually have a lower mobility and to assure the necessity of the resource investment.