• Journal of the speleological society of Korea
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• no.4
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• pp.41-50
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• 1996

The coastal plains of the Puna and Ka' u Districts of the island of Hawaii are a contradiction to the popular view that the island of Hawaii is a tropical rain forest or a vegetated landscape with abundant water sour This section of the island lies in the rain shadow of Mauna Loa a Kilauea Volcanoes and receives less than 30 inches of annual precipita When rain does come. it is in the form of sudden down pours. givi residents of the area little time to collect and conserve water. Due to porous nature of the rock. there is no standing surface water. In spite of these harsh climatic conditions. archeological evidence indic that an extensive agriculture complex existed not only along the coast. into the most remote parts of what is called the Ka'u Desert. Pass through these agricultural areas are historic and pre - historic t systems. These trail systems apparently played a significant suppor role for exchange between the ahupua's (classic land divisions of Haw and the geopolitical districts. The question arises as to how could vast agricultural complexes a heavy foot travel over miles of arid land exist without dependable wa sources\ulcorner While planting - pits and mounds were designed to make most efficient use of available water and conserve moisture(Carter 19 9). people involved in planting also needed potable water for surv Most publications and research papers dealing with the early population this area make only oblique reference to springs and wells which t populations depended upon. The Federal Cave Resource Protection Act(1988) has served as imprtus for the National Park Service to look closer at the lava tu caves and fault cracks within Hawaii Volcanoes National Park. P visitors to these underground areas found large volumes of standing wa in fault cracks. and abundant drip areas with the lava tubes. Re observes noted that in most cases. where the cracks and caves we located in the arid sections of the park. there has been extens modifiacation or utilization of these water sources by the early Hawaii and others. The variety of western containers used for collection indica that these water sources were used during historic times. William E described similar water sources in his narrative of his trip around island in 1823(Eills 1979), This report is directed at documenting recent observations and a stimulating further research into early Hawaiian water collection syst It also explores the implications that power and political influence of e chiefs in the arid portions of Hawaii could have been linked to the con of the water resources.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.2
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• pp.163-172
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• 2016

The aim of this study is to investigate the geological features distributed in the northwest coast, Goheung Gun as a geological field course of all levels. The study area is about 1.6km coast in direction of northwest from Sumundong ferry to Jangsun beach. The learning contents of the geology units in science textbooks from elementary school to high school was analyzed and, geomorphology and geology of study area was investigated for this study. In this study area, lots of geomorphology and geology elements related to the learning contents of the geology units in science textbooks were founded such as gravel beach, sea cliff, granite, rhyolite, andesite, gneiss, sedimentary rocks, fault, unconformity, stratification, cross bedding, graded bedding, intrusion structure, vein, dyke, plant fossil and spheroidal weathering. Characteristically, strata, stratification, granite, sedimentary rocks(conglomerate, sandstone, mudstone and shale), fault, plant fossil and weathering phenomenon were commonly involved with the learning contents of the geology units in elementary school science, middle school science and high school earth science I, II. This area is to be recommended as a site of geological field course for all students from elementary school to high school, as various field work materials for geological learning were distributed and, geological observation trail of about 400m in length for observation of strata and so on was installed along the coast in direction of the northwest from Sumundong ferry.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.569-575
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• 2017

This paper proposes a method to utilize an energy storage system (ESS) based on the assessment of an area of severity (AOS) to voltage sag. The AOS is defined as a set of the fault positions that can cause voltage sags at many buses simultaneously. The assessment of AOS helps to determine an optimal location of ESS installation to minimize the expected sag frequency (ESF) at concerned buses. The ESS has the ability not only to play traditionally known roles but also to mitigate voltage sag impact on renewable energy sources (RES) in the islanded microgrid. Accordingly, using the proposed method the ESS has additional features to prevent the operation failure of RESs and improve the stability of the microgrid. In order to verify the presented method, a case study was conducted on the sample microgrid system that is modified from an IEEE 57-bus system.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.50-52
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• 2008

We have limited the transfer power to capital area below a certain level which is called "The Capital Area Transfer Power Limit", and calculated on every Thursday for the application next week. This level is very important in our network operation, because if this level is not set properly, our power network can be fallen under great danger in case of a fault among the transfer power line. But the calculation procedure for the limit level is so complicated and iterative that it mace us spend much time and do much work. So, when a sudden trip of the related facility to the limit level we can't recalculate the limit level fast enough. And this can drop our network reliability below our standards, therefore our network can be dangerous. To avoid this kind of problems, we have figured out a method to calculate simply the limit level. That method uses the index related to the level. We think this method can make short of the calculation procedures for the level. This paper deals with the simplified method for the calculation of the level limit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.85-92
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• 2011

The role of RCDs(Residual Current Protective Device) that are installed before the load is very important for preventing electric shock and electrical fire. However, although fault rate of RCD is increasing due to deterioration and long period usage, the RCD is permanently used without a checking of performance evaluation and it causes the electrical accident. In this paper, the amount of airborne chloride is researched in domestic costal area and the accelerated life test is conducted using a salt water spray tester in order to decide the life time of RCD. Aa a result of an accelerated life test, the MTTF(Mean Time To Failure) of RCD is 110.81 hours and B10 life time of RCD is 45.81 hours for the all samples. when an accelerated life test result is applied to within 2 km costal area, the life time of RCD is predicted about 5 years.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.9
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• pp.53-60
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• 1997

In this paper, an efficient BILBO(named EBILBO) is proposed for batch testing application when a BIST (built-in self test) circuit is implemented on ASIC. In a large and complex circuit, the proposed algorithm of batch testing has one pin-count that can easily control 4 test modes in the normal speed of circuit operation. For the implementation of the BIST cifcuit, the test patern needed is generated by PRTPG(pseudo-random test pattern generator) and the ouput is observed by proposed algorithm is easily modified, such as the modelling of test pattern genration, signature EBILBO area and performance of the implemented BIST are evaluated using ISCAS89 benchmark circuits. As a resutl, in a circuit above 600 gates, it is confirmed that test patterns are genrated flexibly about 500K as EBILBO area is 59%, and the range of fault coverage is from 88.3% to 100%. And the optimized operation frequency of EBILBO designed and the area are 50MHz and 150K respectively. On the BIST circit of the proposed batch testing, the test mode of EBILBO is able to execute as realtime that has te number of s$\^$+/n$\^$+/(2s/2p-1) clocks simultaneously with the normal mode of circuit operation. Also the proposed algorithm is made of the library with VHDL coding thus, it will be widely applied to DFT (design for testability) that satisfies the design and test field.

• Economic and Environmental Geology
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• v.14 no.1
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• pp.35-49
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• 1981

The studied area is largely occupied by thick piles of the late Cretaceous volcanic rocks of the Yucheon group, which is northeastern border part of the vast volcanic region in the Yucheon basin. The Yucheon group overlies the Geoncheonri Formation and is intruded by granitic and dioritic stocks and dykes. The group can be devided into two parts; the lower is Jusasan andesitic rocks which was called as Jusasan Porphyrite Formation by Tadeiwa in 1929, and the upper is Unmunsa rhyolitic rocks. The volcanic pile consists mainly of various tuffs such as tuff breccia, lapilli tuff, coarse to fine tuff and tuffaceous sediments, and interlayered flows, which range from basaltic andesite to rhyolite in their lithology. The results of petrochemical and volcanostratigraphic studies on the Jusasan andesitic socks suggest that the volcanic rocks were derived from two cyclic evolutions of magmatic fractionation. Systematic study of 5226 joints from the area reveals two sets of steep joints striking $N20^{\circ}-40^{\circ}E$ and $N40^{\circ}-70^{\circ}W$, are dominant and coincide with the fault pattern developed in the area. Three defferent maximum principal stress axes were recognized from conjugate shear joints, which are trending east-west, north-northwest, and north-northeast.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.145-145
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• 2000

Large area YBCO - films are series produced by thermal co-evaporation using a deposition scheme known as Garching process, which allows intermittent oxygen supply in a high vacuum ambient by an oxygen cup spaced closely underneath the moving substrates. The deposition area of 9" diameter is capable to handle very large wafers up to 8" diam. or numerous smaller wafers. The large distance between substrates and boat sources and an elaborate heater design guarantee excellent film uniformity over the entire deposition area. YBCO - films deposited by this technique are commercially fabricated for a variety of applications - the most prominent are resistive fault current limiters and microwave filters for mobile or satellite communications. IMUX and OMUX - filters are currently space qualined by Robert Bosch GmbH and are expected to be launched and installed on an experimental platform of the international space station ALPHA in 2001. Both of the above applications require quite different film specifications on the one hand, but at the same time extremely high uniformity and reproducibility on the other hand, since hundreds of YBCO - films are combined to large systems or have to be approved for manned space missions. The success of such projects is direct evidence that the technique of thermal evaporation is readily capable to meet these high demands and has become the major deposition technique to support the emerging HTS market.

• Economic and Environmental Geology
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• v.26 no.2
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• pp.155-166
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• 1993

Gold contents with major and trace elements have been determined in 67 fresh igneous and altered wall rocks in the acid-sulfate alteration zone of the Ogmaesan-Seongsan pyrophyllite deposits in the Haenam area of the south-western part of Korean peninsula. The results are as follows; (1) Li contents have a tendency to show high value in dickite and altered rocks with dickite, while As, Mo and Sb contents have tendencies to show high values in alunite vein and silicified zone. F contents are higher in the altered rocks compared to fresh rocks. (2) Gold contents are enriched in alunite vein and silicified zone of the Seongsan deposit, but depleted in dickite and altered rock with dickite. Gold contents are especially concentrated in fault or conjunction area of two faults. (3) Gold contents are higher values in the mineral assemblages of alunite-quartz-pyrite and alteration zone of the Seongsan deposit among the studied deposits. (4) Gold contents in samples of silicified zones tend to show positive correlations with Ag, As, Co, Hg, Sb and V content, but negative correlations with Y and Zr contents, while on the other gold contents of silicified tuffs tend to show positive correlations with Hg and Sb contents. Therefore it is important to survey alunite vein and silicified zone at the conjunction of faults, and to analyze pathfinder elements such as Ag, As, Hg and Sb for geological and geochemical exploration of gold in the studied deposits.

• Ocean and Polar Research
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• v.29 no.4
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• pp.303-310
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• 2007

2-D wavelet analysis is applied to bathymetric data from the KR1 area of Korea Deepsea Mining Area. The wavelet analysis is one of the quantitative methods to analyze the topography. The wavelet allows us to create filters to select for topography in a continuous variety of shapes, sizes, and orientation. The 2-D Linear B-spline filter, 100 BS and 100 NF, is convolved with bathymetric data to identify the location of abyssal hills and abyssal troughs in bathymetry. In addition, the 2-D derivative of Cubic B-spline filter, 60 BS and 60 NF, is applied to bathymetric data to find the slope of abyssal hill in bathymetry. These filters were rotated $5^{\circ}$ counterclockwise from NS to match the dominant orientation of seafloor lineament. Both filters result in good match with abyssal hills, troughs, and slopes. This method can apply to fault, fold, and other lineament structures description with variable size. The result of application shows that wavelet analysis of bathymetric data could be used with fundamental data of geophysical analysis.