• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.25 no.1
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• pp.57-81
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• 1997

Numerical prediction of nocturnal thermal high in summer of the 1995 near Taegu city located in a basin has been carried out by a non-hydrostatic numerical model over complex terrain through one-way double nesting technique in the Z following coordinate system. Under the prevailing westerly winds, vertical turbulent fluxes of momentum and heat over mountains for daytime hours are quite strong with a large magnitude of more than $120W/\textrm{m}^2$, but a small one of $5W/\textrm{m}^2$ at the surface of the basin. Convective boundary layer (CBL) is developed with a thickness of about 600m over the ground in the lee side of Mt. Hyungje, and extends to the edge of inland at the interface of land sea in the east. Sensible heat flux near the surface of the top of the mountain is $50W/\textrm{m}^2$, but its flux in the basin is almost zero. Convergence of sensible heat flux occurs from the ground surface toward the atmosphere in the lower layer, causing the layer over the mountain to be warmed up, but no convergance of the flux over the basin results from the significant mixing of air within the CBL. As horizontal transport of sensible heat flux from the top of the mountain toward over the basin results in the continuous accumulation of heat with time, enhancing air temperature at the surface of the basin, especially Taegu city to be higher than $39.3^{\circ}C$. Since latent heat fluxes are $270W/\textrm{m}^2$ near the top of the mountain and $300W/\textrm{m}^2$ along the slope of the mountain and the basin, evaporation of water vapor from the surface of the basin is much higher than one from the mountain and then, horizontal transport of latent heat flux is from the basin toward the mountain, showing relative humidity of 65 to 75% over the mountain to be much greater than 50% to 55% in the basin. At night, sensible heat fluxes have negative values of $-120W/\textrm{m}^2$ along the slope near the top of the mountain and $-50W/\textrm{m}^2$ at the surface of the basin, which indicate gain of heat from the lower atmosphere. Nighttime radiative cooling produces a shallow nocturnal surface inversion layer with a thickness of about 100m, which is much lower than common surface inversion layer, and lifts extremely heated air masses for daytime hours, namely, a warm pool of $34^{\circ}C$ to be isolated over the ground surface in the basin. As heat transfer from the warm pool in the lower atmosphere toward the ground of the basin occurs, the air near the surface of the basin does not much cool down, resulting in the persistence of high temperature at night, called nocturnal thermal high or tropical night. High relative humidity of 75% is found at the surface of the basin under the moderate wind, while slightly low relative humidity of 60% is along the eastern slope of the high mountain, due to adiabatic heating by the srong downslope wind. Air temperature near the surface of the basin with high moisture in the evening does not get lower than that during the day and the high temperature produces nocturnal warming situation.

• Science of Emotion and Sensibility
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• v.5 no.1
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• pp.71-78
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• 2002

Driving involves a series of complicated precesses requiring various human capacities, such as perception, will decision, and athletic functions. Consequently, it induces a high degree of continuous concentration of mind and tension from external stimulation, bringing fatigue to the driver, and driver fatigue is counted as one of the major causes of traffic accidents. Nevertheless, because of the complicated urban lives, traffic congestion, job characteristics, and so on, the drivers have to spend a longer time inside a vehicle, and the fatigue and stress thereof is almost unavoidable. We haute, therefore, turned our attention to the reduction in the fatigue during driving by supplying oxygen, and investigated in this research the drivers subjective fatigue evaluations and reaction time when oxygen is supplied in different rates. As a result, we have found that the subjective fatigue feeling is highest at low-rate O/Sub 2/ supply (18%), and fatigue feeling was comparatively reduced at high-rate O/Sub 2/ (30%). The sleepiness also showed the tendency to be reduced at high-rate O/Sub 2/ supply in the case of driving for 1 hour or more. The time for reaction to braking after the sign for urgent stop is given tends to show more substantial reduction at high-rate O/Sub 2/ supply than at low-rate O/Sub 2/ supply after 2 hours driving. It can, therefore, be deduced from the aforesaid results that the subjective responses and behavioral reactions tend to show reduced fatigue at the condition of high-rate O/Sub 2/ supply. Hence, it was suggested that drivers felt subjective fatigue while driving at low-rate O/Sub 2/ and the subjective fatigue and reaction time were reduced at high-rate O/Sub 2/. These findings suggest that the oxygen supply will reduce driver fatigue.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.149-157
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• 1998

Seasonal changes of topography, sediment grain size and accumulation rate in the Gomso-Bay tidal flat, west coast of Korea, have been studied in order to understand the seasonal accumulation pattern and preservation potential of the tidal-flat sediments. Seasonal levelings across the tidal flat show that the landward movement of both intertidal sand shoals and cheniers accelerates during the winter and typhoon periods, but it almost stops in summer when mud deposition is instead predominant at the middle and upper tidal flats. Seasonal variations of mean grain size were largest on the upper part of middle tidal flat where summer mud layers were eroded during the winter and typhoon periods. Measurements of accumulation depths from sea floor to basal plate reveal that accumulation rates were seasonally controlled according to the elevation of tidal-flat surface. The upper tidal flat where the accumulation rate of summer was generally higher than that of winter was characterized by a continuous deposition throughout the entire year, whereas in the middle tidal flat, sediment accumulations were concentrated in winter relative to summer and were intermittently eroded by typhoons. The lower tidal flat were deposited mostly in winter and eroded during summer typhoons. Can cores taken across the tidal flat reveal that sand-mud interlayers resulting from such seasonal changes of energy regime are preserved only in the upper part of the deposits and generally replaced by storm layers downcore. Based on above results, it is suggested that the storm deposits by winter storms and typhoons would consist of the major part of the Gomso-Bay sediments.

• Journal of the Korean Geographical Society
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• v.49 no.6
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• pp.849-864
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• 2014

The objective of this paper is to investigate both the processes of regional policy and their determinants of the International Garden Exposition Suncheon Bay Korea 2013(IGEXPO 2013). IGEXPO 2013 was held in Suncheon from April to October 2013, and almost 440 million tourists visited to IGEXPO 2013. The processes of regional policy of the IGEXPO initiative were divided into four stages; the first stage from 1992 to 2002 was a beginning of conservation movement for Suncheon Bay; the second stage from 2003 to 2007 was a constructing of natural ecological park of Suncheon Bay; the third stage from 2008 to 2010 was a beginning of IGEXPO initiative and a confirming of the IGEXPO 2013; the four stage from 2011 to 2013 was a preparing and holding of IGEXPO 2013. The major determinants related to regional policy development process of IGEXPO initiative are the population n movement for Suncheon Bay, the rergional development strategy for central city in Gwangyang Bay area, the leadership for continuity of regional policy oriented to environmental and ecological city, and the cooperation and competition relationalship with neighboring city, in particular Yeosu city and 2012Yeosu EXPO planning. IGEXPO 2013 has been evaluated as having some performances such as the enhancement of city image, establishment of city park as a public goods, and formation of community leadership promoting continuous urban policy for environmental & ecological city.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.2
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• pp.109-119
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• 2012

Long-term wave observation was carried out near Busan New Port and the major wave characteristics were analyzed. At Busan New Port, waves from south direction were predominant throughout the year, while waves from the west, developed at the north sea of Geoje island, appeared almost the same frequency in winter season, showing apparent seasonal variation. During the observation period, the significant wave height was mostly less than 1 m, but it reached its maximum of 8.0 m when typhoon Maemi passed on September 2003. Also, the seasonal variation was hardly observed except July. In contrast, seasonal variation was apparent for the significant wave period, whose peak ranges 4~5 s in summer whereas about 3 s in winter. The largest significant wave period was 15.56 s, observed on June 2003. Meanwhile, the annual variation was negligible for mean wave direction as well as significant wave height and period. Further analysis of the wave data acquired for 5 years at 4.5 km south, in the south sea of Daejuk island, confirmed high correlation between the two observation points in summer and vice versa in winter.

• Journal of Distribution Science
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• v.12 no.12
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• pp.101-106
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• 2014

Purpose - This study reviews the achievements of a pilot project for the revitalization of a commercial district performed for three years after its establishment in 2011. The project for the revitalization of the commercial district was performed to create a new local community space in connection with the traditional market and nearby districts. Although it was a pilot project, the project for the revitalization of the commercial district has been performed for almost three years. Therefore, this seems a proper time to conduct an interim evaluation of the project. This study aims to review and evaluate how the government support policy is influential for the revitalization of the commercial district. In other words, this research aims to identify what projects positively affected consumers' intention to revisit the downtown commercial area among the commercial district revitalization projects-promotion events, promotion activities, education, merchants cooperation system, IT projects, cultural events, and residents' communication. Research design, data, and methodology - This study designated seven management improvement projects affecting commercial district revitalization based on preceding studies. The survey of the degree of satisfaction on seven management improvement projects was executed targeting consumers who visited the commercial areas. Additionally, visitors' revisit intentions regarding currently visited commercial areas were also investigated. Therefore, revisit intention was set as a dependent variable and the satisfaction degrees of the respective management improvement projects were set as the independent variables. A total of 1,209 consumers were examined in six districts in the country. Result - Multiple regression analysis results showed that cultural events, education, the merchants' cooperation system, and IT projects brought statistically significant effects to the revisit intentions of consumers. In contrast, promotion events, resident communication projects, and promotion activities did not affect the revisit intentions of consumers. Particularly, the residents' communication project did not show significant influence because of consumers' recognition that it is similar to a cultural event. Conclusion - The following implications for the revitalization of business districts in the urban central area are drawn. From a general perspective, the businesses of culture, education, and cooperative system among seven businesses play positive roles regarding the intention to revisit so that the project is required to be promoted periodically through unique performances differentiated for each district, the merchant training reinforced for professionalism, and the expansion of joint events of merchants. Moreover, the sales promotion project and public relations activity are shown to be not influential to the intention to revisit. Therefore, while short-term sales promotion such as one-time gift events are required, sales promotion and public relation activities to induce revisits by mileage savings and accumulated gift presentation to attract long-term customers are required. The IT business is positively influential to the intention of revisit. Therefore, detailed information on the revitalized commercial district should be provided and additional functions such as discount coupons for continuous utilization should be included in the mobile app and the website.

• Economic and Environmental Geology
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• v.29 no.1
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• pp.45-55
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• 1996

Although the Dongjin Au-Ag-Cu mine had been abandoned since about forty years ago, the results of this study on the dispersion patterns and contamination level of heavy metals in the hydrologic system flowing via the waste rump show that the environmental impacts from the mine wastes are still significant. The stream water in the vicinity of the waste rump is severely acidified (pH 3.8 to 4.4) and highly enriched in various dissolved heavy metals. The heavy metal contents of the stream water and stream sediments are systematically attenuated with increasing distance from the mine area. However, it is worth to note that continuous attenuation of heavy metal contents in both media were reenriched in downstream area more than 800 m apart from the mine because it can be acted as a secondary source of heavy metal pollution. The heavy metals, especially Cd, Cu and Zn of polluted downstream sediments mainly occur in Fe-Mn oxides and organic materials, which indicates that these elements are the main pollutants from the waste rump of the Dongjin mine. The heavy metal contents of crops, such as sesame, perilla, red Pepper and brown rice, collected from the polluted farm land in the downstream area are lower than those of land plants from stream sides, but significantly higher in Cd, Cr, Cu and Zn than those from the unpolluted farm land. Especially, almost all of the crops in polluted farm land have been severly contaminated by Cd (>0.4 ppm). On the other hand, the heavy metal contents of the crops collected from refreshed farm land by means of a soil addition method shows significantly lowered level comparing with those of polluted area, which indicates that a soil addition method was effective for the refreshment of polluted farm land by toxic metallic pollutants. Wormwoods from this area showed very high contents in a11 the heavy metals even in unpolluted area (Cd > 1 ppm, Cr > 1 ppm, Cu > 11 ppm, Pb> 4 ppm, Zn > 55 ppm), indicating that a special caution must be payed when one takes ingest them.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.62-69
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• 1999

With increased utilization of chemical fertilizer, soil fertility is getting serious problem. As a result, using organic soil conditioner (woody wastes or sawdust compost) would be only solution to recover soil vitality. In this study, manufacturing and characteristics of organic soil conditioner from Shiitake bedlogs (woody wastes) were studied. Also, to investigate the effect of continuous application of this bedlog compost on growth of plants, growth tests for radish and tree seedlings were done. The results are as follows ; Analytical results of decayed and fresh wood materials showed almost same as its wood components. The mixing ratio of raw materials with the other filling materials is essential for the manufacturing as well as good quality of its compost during composting process. In this experiment, mixing 12kg of urea, 25kg of lime, 40kg of chicken shit, and small amount of fermentation aids corresponding to I ton of sawdust resulted in good composts. Their moisture contents were adjusted to about 55%. Temperature of pile, in composting process, rose after I week and kept about above $60^{\circ}C$ for certain period. They were turned two times, 30th and 59th day, respectively, after piling. This bedlog compost contained 81.7% of high organic matter, 1.4% of a little nitrogen, 6.75 of pH and 25 - 30 of C/N ratio. There were no harmful effect on germination and growth of plants, such as radish and softwood and hardwood seedlings. Concerned to the effect of bedlog compost on soil temperature, the compost did not affect plant growth by changing soil temperature abruptly, but compensated the soil temperature such as a little increasing on the early morning, a little decreasing on the mid-day or afternoon (pm 2:00), and increasing on the early evening (pm 6:00).

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.350-357
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• 2017

Purpose: In-situ monitoring of water quality is fundamental to most environmental applications. The high cost and long delays of conventional laboratory methods used to determine water quality, including on-site sampling and chemical analysis, have limited their use in efficiently managing water sources while preventing environmental pollution. The objective of this study was to develop an on-site water monitoring system consisting mainly of an Arduino board and a sensor array of multiple ion selective electrodes (ISEs) to measure the concentration of $NO_3$ ions. Methods: The developed system includes a combination of three ISEs, double-junction reference electrode, solution container, sampling system consisting of three pumps and solenoid valves, signal processing circuit, and an Arduino board for data acquisition and system control. Prior to each sample measurement, a two-point normalization method was applied for a sensitivity adjustment followed by an offset adjustment to minimize the potential drift that could occur during continuous measurement and standardize the response of multiple electrodes. To investigate its utility in on-site nitrate monitoring, the prototype was tested in a facility where drinking water was collected from a water supply source. Results: Differences in the electric potentials of the $NO_3$ ISEs between 10 and $100mg{\cdot}L^{-1}$ $NO_3$ concentration levels were nearly constant with negative sensitivities of 58 to 62 mV during the period of sample measurement, which is representative of a stable electrode response. The $NO_3$ concentrations determined by the ISEs were almost comparable to those obtained with standard instruments within 15% relative errors. Conclusions: The use of the developed on-site nitrate monitoring system based on automatic sampling and two-point normalization was feasible for detecting abrupt changes in nitrate concentration at various water supply sites, showing a maximum difference of $4.2mg{\cdot}L^{-1}$ from an actual concentration of $14mg{\cdot}L^{-1}$.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.195-208
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• 1997

On the basis of the topographic maps in the 1910's and 1990's and the classification map of Landsat TM satellite image photographed on Sept 1, 1996, the spatial distribution and the current situation concerning tidal flats in Korea were studied by measuring the area with GIS Arc/Info system and examining the regional condition required to develop the tidal flats. The results are as follow; The tidal flat resources in Korea cover an area of about 3800 square meters, including the reclaimed one since the 1910's. And they are widely distributed in the west coast of South Jeonla, Kyunggi bay, Asan bay, the south coast of South Jeonla, Kunsan bay, Chunsoo bay, and the coast of South Kyungsang and Pusan when put in the order from bigger area. Given the area under the construction at present, more than 50% of the tidal flats are reclaimed ones. The tidal flats are being developed especially in Kyunggi and Asan bays because they perfectly measure up to the conditions required. For Kunsan bay, a remarkably good supply system of the alluvial sedimentary materials and a favorable coastline requirement for the coast of the South Jeonla also contribute to the development of the tidal flats. In the case study of Kunsan bay, it was shown that the shape of the tidal flat is making a continuous change and the area is getting bigger in terms of the multi-temporal change of the tidal flat development. However, while in the first half of the 20th century, the increasing rate of the area was considered to be rather high, it is considerably lowered almost to a standstill in the latter half of the century.