• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.755-758
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• 1999

Reinforced concrete is in general known as high durability construction material under normal environments due to strong alkalinity of cement. Marine and harbour concrete in the tidal and the splash zone at seashore are exposed to cyclic wet and dry saltwaters which cause to accelerate corrosion of reinforcing steel in concrete. If corrosion resistance of concrete gets to weaken due to carbonations and cracks in cover concrete, furthermore, concrete durability rapidly decreases by corrosion of reinforcement steel embedded in concrete. The objective of this study is to develop appropriate corrosion protection systems so as to enhance the durability of concrete by controlling the cover depth of concrete and by using corrosion inhibitors as concrete admixtures.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.281-286
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• 2001

The development of automobile, vessel, rail road, and machine industry leads increase of foundry production used as their components, which cause a by-product, waste foundry sand (WFS). The amount of the WFS produced in Korea is over 900,000 ton a year, but most WFS buries itself and only 5~6% WFS is recycled as a material in construction materials. In this study, WFS is used as a fine aggregate for concrete. Five types of concretes aimed at the specified strength of 240$\pm$10 kgf/$cm^{2}$ , air contents of 4.5$\pm$1% and slump of 12$\pm$1.5cm were mixed with washed coarse seashore sand(WFS) in which salt was removed and then optimum mix proportion of concrete was determined. Moreover, basic properties such as setting time, workability, bleeding and slump loss of the fresh concrete with WFS were tested and compared with those of the concrete mixed without WFS. In .addition, both compressive strength of hardened concrete at each ages and tensile strength of it at the age of 28 days were measured and discussed.

• Journal of Ocean Engineering and Technology
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• v.11 no.2
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• pp.113-121
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• 1997

With the increase use of electromagnrtic distance measuring equiment, is is required that we need to study the higher dimensional applications and detail technical methods. The purpose of this paper is to improve the accuracy of ocean construction surveying and computer programming for determining of horizontal position of a quadrilateral by measuring line on traverse surveyng, trigulation and trilateration. Aa long distance measurements with high accuracy became possible by the apperance of EDM distance measuring instruments, we induced correct adjustment equation through angle condition and area conditionequation. After that we compared and experimental model. From its a result of the practical applicationto quadrilateral, it has been found that its triangulation and traverse surveying algorithms provide better accuracy than trilateration.

• Journal of Environmental Science International
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• v.3 no.4
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• pp.333-348
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• 1994

The groundwater levels at 11 sites and the vertical variations o( the water Quality at 1 site were measured to study the characteristic of the groundwater level fluctuation of Cheju Island. The results of the measurements for the groundwater levels were as follows; In the eastern part, inculding Kimnyong, Jongdal and Sungsan, a sinusoidal fluctuation of groundwater levels occurred in response to oceanic tides. The tidal effect on the groundwater level was reduced depending upon the distance from seashore. But time lag showed that the trend is reversed. However, in the Samyang, Kosan and Shinhyo areas show that the groundwater level was directly influenced by the amount of precipitation. Especially, Shinhyo area which southern part in Cheju was affected the most and show upper parabasal groundwater level. In Susan- I which eastern part in Cheju, well rovealed that water Quality changed with the period of a tide. Salinity at the lim, bellow the natural groundwater level, was approched to the brackish groundwater(1000ppm).

• Journal of electromagnetic engineering and science
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• v.12 no.1
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• pp.94-100
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• 2012

Radio interference has been occurring in mobile communication services on the southern seashore in Korea. Monitoring the radio interference signal revealed that the main reason for the radio interference was a radio ducting signal coming from the seaside of Japan. In this paper, we have analyzed the effect of interference on WiMAX service using a 2.5 GHz frequency band between Korea and Japan. We focus on the interference scenario from base station to base station and we use the Minimum Coupling Loss (MCL) method for interference analysis and the Advanced Propagation Model (APM) for calculating the propagation loss in ducts. The propagation model is also compared with experimental measurement data. We confirm that the interfering signal strength depends on the antenna height and this result can be applied to deployment planning for each system with an interference impact acceptable to both parties.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.198-203
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• 1998

This study, a sub-one of comprehensive research works titled under “Rural Resources Evaluation System”, tried to verify utility/applicability of the developed model system through the case study works on 3 sample villages, Backya, Uyan and Suyu, representing the lowland, upland and seashore villages respectively. From the various surveying and collecting works including the official/statistical data collection, map analysis, insitu investigation, field survey and written material review, the original data set were obtained and manipulated into final input data for resources grading. After then, by the automatized calculation procedure of “Rural Resources Evaluation System”, score results for resources evaluation were finally produced with the total maximum score being 1,000. Through comparing works among score results of 3 case villages and between score results and areal characteristics of each case village, the applicability of the system developed in this study was well confirmed.

• International Journal of Concrete Structures and Materials
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• v.6 no.4
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• pp.251-256
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• 2012

This paper presents an experimental study on the pore and penetration of chloride in seashore concrete depending on types of curing forms. Three types of concretes (Plain concrete, MSF concrete and FA concrete) with four different form types (wood, coating wood, steel and polypropylene film) were examined. The test results show that the air volume in concrete was relatively higher with steel and polypropylene forms than others, and wood form shows the least air volume. The penetration of chloride depending on type of form is showed a wide variability, that is, the values on plain concrete, MSF concrete and FA concrete are 115.2, 125.5 and 121.6 %, respectively. Based on the present study, concrete should be considered the conditions of curing form-type for durable concrete.

• Animal Systematics, Evolution and Diversity
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• v.33 no.4
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• pp.262-266
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• 2017

Flies of the genus Scatella are small and dark-gray, and many species have distinctive whitish spots on their gray wings. Most species are found in damp environment, such as the borders of marshes, seashore areas, swamps, lakes, ponds, streams, and paddy fields. The Korean shore fly genus Scatella Robineau-Desvoidy has been taxonomically noted. A total of five species have been identified: S. calida Matsumura, 1915, S. nipponica Miyagi, 1977, S. obsoleta Loew, 1861, S. paludum (Meigen, 1830), and S. tenuicosta Collin, 1930. This is the first report of S. calida Matsumura, 1915 from Korea. A key to the Korean Scatella species and photographs of the external features have been provided.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.74-80
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• 1978

To identify new herbicides for the control of Scirpus maritimus and evaluate the performance of some promising herbicides for transplanted rice, field experiments were carried out in the reclaimed paddy fields.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.28-34
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• 2007

Recently, with the rapid growth of industry, environmental condition became worse. In addition to outdoor insulators in seashore are polluted due to salty wind. Also this pollution causes the flashover and failure of electric equipments. Especially the salt contaminant is one of the most representative pollutants, and known as the main source of the accident by contamination. As well known, the pollution has a close relation with meteorological factors such as wind velocity, wind direction, temperature, relative humidity, precipitation and so on. In this paper we have statistically analyzed the correlation between the pollution and the meteorological factors. The multiple regression analysis was used for the statistical analysis; daily measured equivalent salt deposit density(dependent variable) and the weather condition data(independent variable) were used. Also we have developed an expert program to predict the pollution deposit. A new prediction system using this program called SPPP(salt pollution prediction program) has been used to model accurately the relationship between ESDD with the meteorological factors.