• Journal of the Korean Institute of Navigation
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• v.18 no.1
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• pp.23-30
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• 1994

By use of the Climatological Report(1982~1991) and the Marine Casualty Report(1982`1992), marine casualties caused by meteorological factors and climatic characteristics along Korean coast were analysed. Marine casualty by meteorological factors can be classified into three kinds such as collision, aground and sinking. On the whole collision was mainly caused by dense fog and heavy precipitation, and aground and sinking was caused by strong wind and high sea. As results of analysis of the distribution of wind, fog and precipitation at major ports in Korea, climatic characteristics along Korean coast are as follows. in the eastern coast, wind was relatively weak and fog was not so frequently formed, while strong wind blew all the year round and fog appeared from April to August in Ulleung Island. In the southern coast, the wind was strong in both winter and summer, fog formed frequently in late spring through mid-summer and heavy precipitation was in summer. Typhoon affecting Korea was usually passing this area to the East Sea. In the western coast, strong wind was prevailing in winter at southern region and fog was formed very frequently throughout the year.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.231-238
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• 2005

Incompetent sediments and competent volcanics are consisted of the Cenozoic geology in Korea. Although the Cenozoic area is small, it is necessary to special interesting for ground of these geological material. The Cenozoic geology shows heterogeneous characteristics. We can look at the weak Cenozoic sedimentary rocks under the hard Cenozoic basalt in the area. Some Cenozoic un(or half)-consolidated soft sediments have large, heavy and hard boulders. Some volcanics and tuffaceous sediments have swelling clays. These characteristics give very difficult problems to engineering geologists and civil engineers.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.163-166
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• 2003

The seasonal mean wind direction and wind speed in a greater coasting area are investigated using the ECMWF(European Centre for Medium-Range Weather Forecasts) data for 11 years from 1985 to 1995. In winter, the main wind direction in Korea and vicinity, Taiwan and vicinity, and the North Pacific Ocean of middle latitudes is a northwesterly wind, northeasterly wind, and westerly wind respectively. The wind speed is strongest in the East China Sea, the South China Sea, and the North Pacific Ocean of low latitudes(Beaufort wind scale 5-6). A distribution pattern of wind direction in spring and fall is similar to that in winter. Seasonal mean wind speed is strongest in winter and the next is fall. The wind speed in summer is generally weak. However, that in the Indochina and vicinity is strong by the influence of Asian monsoon.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.609-611
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• 2006

This paper describes a CMOS sub-bandgap reference using Pseudo-Resistors which can be widely used in flash memory, DRAM, ADC and Power management circuits. Bandgap reference circuit operates weak inversion for reducing power consumption and uses Pseudo-Resistors for reducing the chip area, instead of big resistor. It is implemented in 0.35um Standard 1P4M CMOS process. The temperature coefficient is 5ppm/$^{\circ}C$ from $40^{\circ}C$ to $100^{\circ}C$ and minimum power supply voltage is 1.2V The core area is 1177um${\times}$617um. Total current is below 2.8uA and output voltage is 0.598V at $27^{\circ}C$.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.848-857
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• 2008

In September 2007, the collapses of slopes and landslides are happened at Jeonlanamdo due to heavy rains accompanied with Typoon "Nari". The study area is the tunnel portal slope in new road construction site. This slope consists of pyroclastic rocks and has lots of faults. Particularly, the residual soils of the slope is deteriorated with yellowish mudstone layer as a results of chemical and physical weathering. This has a variety of swelling clay minerals and might be moved easily down at the gentle terrain. The inner factor of $\bigcirc\bigcirc$tunnel portal slope's collapse is the geological weak zone, the convergent topography, the inferiority of drainage and the heavy rain act on the failure as direct trigger.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.687-696
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• 2005

Safety diagnosis was conducted to evaluate the long-term stability evaluation of power transmission tower of which deformation of the upper structural elements occurred. To assess the cause of the structural deformation, field investigation including BIPS, down-hole test, concrete pile coring and finite element analysis were carried out. From these studies, the major cause of deformation was found due to the heavily fractured layer and weathered soil topography at the pile tip area. The cement-milk grouting method was proposed to reinforce these weak zone around the pile tip area. Also, the increase of cross-section and stiffness for steel members of upper tower structures was suggested. Instrumental monitoring was proposed as well to verify reinforcing effect.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.757-764
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• 2004

This paper deals with the numerical study on the displacement behavior of corner areas in an excavation site. Several corner areas always exist in the excavation site. The corner area has two free surfaces, which may become serious weak point from the viewpoint of structural stability. If the structural reinforcements are not applied adequately in corner areas, significant displacement of retaining wall could occur. What is worse, the collapse of retaining system rarely happens. In this paper, 3D numerical analyses were performed to investigate the effect of the arrangement of diagonal and normal strut. From the analysis results, it is found that the spacing between diagonal strut and normal strut should be less than 4m to avoid excessive displacement due to excavation.

• International Journal of Fluid Machinery and Systems
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• v.1 no.1
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• pp.47-56
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• 2008

The flow behind the variable area nozzle which corresponds to the flow at the leading edge of the impeller was measured with a 3-hole yaw probe and calculated with CFD. Two nozzle throat-areas were investigated. One is the smallest and the other is the largest opening for the variable nozzle. Test results agreed with the calculated results qualitatively. The leakage flow through the tip clearance of the nozzle vane significantly affected the flow field downstream of the nozzle vane with the smallest opening. However, the effect on leakage flow on the flow field downstream of the nozzle vane with the largest opening was very weak and the effect of wake is dominant.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.877-884
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• 2011

Although peak loading coefficient is one of critical design factors for sewer works, its detailed affecting factors were not analyzed because of limited data availability. This study analyzed the affecting factors on peak loading coefficient with plenty data obtained from several newly constructed sewer works. Simple and multiple regression analysis methods were adopted to analyze the relationships of each variable with or without data filtering. Drainage population, drainage area, population density, and daily sewage flow per person showed very weak relationships under diverse characteristics of cities. However, daily sewage flow per person showed stronger relationships with peak loading when daily sewage flow per person was splitted into two ranges. Population density (i.e., drainage population divided by drainage area) and daily sewage flow per person considerably were related with peak loading coefficient when daily sewage flow per person is less than about 400 Lpcd.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.144-152
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• 2017

Among the technologies for implementing autonomous vehicles, advanced driver assistance system is a key technology to support driver's safe driving. In the technology using the vision sensor having a high utility, various preprocessing methods are used prior to feature extraction for lane detection. However, in the existing methods, the unnecessary lane candidates such as cars, lawns, and road separator in the road area are false positive. In addition, there are cases where the lane candidate itself can not be extracted in the area under the overpass, the lane within the dark shadow, the center lane of yellow, and weak lane. In this paper, we propose an efficient preprocessing method using k-means clustering for image division and the HSV color model. When the proposed preprocessing method is applied, the true positive region is maximally maintained during the lane detection and many false positive regions are removed.