• Korean Journal of Environmental Agriculture
• /
• v.2 no.1
• /
• pp.35-44
• /
• 1983

In order to elucidate the change of plant community of natural forests caused by air pollution in the area of Mt. Dosjil of Ulsan city, 25 study subplots, 5 subplots from each 5 plots were set up. These plots lay along gradients of chronic exposure to airborne sulfur dioxide ($SO_2$), fluorides(F) and possibly other pollutants. Total nitrogen, organic matter, available $P_2O_5$, and CEC were generally depressed near industrial sourecs of air pollutants. The author found a total 7 species near sources of air pollutants and 13 species at the utmost plot from air pollutants. Number of individuals, species diversity, evenness, similarity index and biomass were generally depressed near the industrial source of air pollutants. Tolerant plants to air pollution is Cyperus amuricus, Calamagrostis arundinacea, Bidens bipinnata, Cocculus trilobus, Digtaria sanguinalis, Persicaria hydropiper, Pinus thunbergii, Ambrosia artemisiifolia var. elatior, Rhododendron schlippenbachii and Robinia pseudoacacia. It contains 4.41ton/ha of aboveground biomass of Robinia pseudoacacia in damaged forest by air pollution and 39.47ton/ha of it in the non-attacked forest. The annual net production is 0.67ton/ha. yr in damaged forest and $7.73ton/ha{\cdot}yr$ in the non-attacked forest.

• Journal of Energy Engineering
• /
• v.24 no.2
• /
• pp.129-143
• /
• 2015

Increasing concerns on climate change and energy security accelerated policies to reduce green-house gas emission, especially from the transportation sector. Electric vehicle (EV) has been on the spotlight to deal with such environmental issue and V2G (Vehicle-to-Grid) technology began to draw attentions as an alternative to reduce ownership costs while contributing to an efficient and decentralized power grid. This study conducts a scenario analysis on total cost of ownership of EV under V2G scheme and compare with non-V2G EV and Internal Combustion Engine (ICE) vehicle. As result, V2G service is expected to provide an annual average profit of $210 to EV users willing to reverse flow its residual power in the battery. The profit from V2G service leaves a margin of $4,530 over operational lifetime, compared with $2,420 cost of charge for non-V2G EV. In summary, total cost of ownership of V2G-capable EV was 6.2% less than non-V2G EV and 10.2% higher than ICE vehicle. The results confirm a comparative economic advantage of operating EV under V2G scheme. Increased number of EVs with V2G service has shown to provide positive effects to power industry for valley filling in load distribution, thus, favorably increasing the overall economic feasibility.

• Health Policy and Management
• /
• v.8 no.1
• /
• pp.15-51
• /
• 1998

compensation is a major function of human resources management. The hospital industry is characterized by its remarkable labor intensity and human resource input by unit. That is why the hospital industry has a higher level of wage/cost ration. The issues of how much the hospital personnel's direct financial compensation amounts to and how the organizational and other factors generate compensation differentiation, are central problems for research in hospitals. But there have been few approaches to study staff compensation in hospitals, its magnitude and inter-hospital relative compensation amounts for the same personnel. A worker who moves from low-wage to a high-wage employer can usually increase his or her pay without change in job description. This means in the cases of same jobs, relative importance is different for each hospitals. The purpse of this study were to find the compensation levels of hospital personnel and to determine the factors affecting compensation levels of hospital personnel. The unit of analysis is the hospital and 145 hospitals were studied for nurse(RN), medical technoloist(MT), managerial personnel(MP) and 100 hospitals for medical doctor(MD). In this study the definitions of direct financial compensation are before tax, excluding employer's contriution and total annual remuneration received by the employee. Main findings of the research can be summarized as follows. 1. Direct financial compensation of hospital personnel are MD 45,056,000 won, RN 9,222,000 won, MT 9,513,000 won and MP 9,185,000 won in the starting year's employment in hospital. 2. According to determinants of hospital personnel compensations, there are no statistical significant variables to determine the level of MD's compensation. Wlith RN and MT's compensation level, the greater the patient revenue per 100 hospital beds, the higher the RN compensation and the tertiary hospital's compensation is much more than other types of hospitals. The location of hospital is another determinant factor for the MT's compensation level. Hospitals that are in the uban area have lower compensation level than rural area. There are the same results in MP with MT. Conclusions can be drawn from the results of the study. First, the wage differentiation of MD and other health personnel still remains and the differentiation existed in inter and intra job personnel of hospitals. Second, determinants of hospital personnel personnel compensation level are patient revenue, location, and type of hospital level.

• Journal of the Korean Society of Industry Convergence
• /
• v.12 no.2
• /
• pp.79-83
• /
• 2009

In this study, actual state of operation of rotary tillage was surveyed in the central part of Korea which includes 29 rural community around Asan city, Choongnam principal. 29 heads of the village and 44 farmers were surveyed at the field with a questionnaire on the operation of rotary tillage with farm tractors. Power requirement of rotary tillage operation was measured at the field of each farmers during rotary tilling operation in the central part of Korea. Summaries of this study are summarized as follows. 1) Operations of tillage and land preparation were found to be carried out with farm tractors by 98 percents which are results of the survey on 29 heads of the village and 44 farmers. 2) More than half of the farms had tractors with horsepower more than 38 kW which states that most tractors were supplied in middle and large size. 3) The case of applying secondary tillage after the first primary tillage were 79 percent among the most of operations of tillage and field preparation. Rotary tillage were carried out on the most of wet paddy fields and only 14 percent of dry fields were cultivated with rotary tillage. 4) 63.6 percent of farm tractors were surveyed to meet the recommended field capacity on tillage operation by the government which were ranged from 15.1 to 34.9 ha. And the field capacity of these farm tractors were greater than that of annual total area of operation field, 13.2ha (data from Information of agricultural machinery, National agricultural products quality service, Korea), which states the utilization of agricultural machinery was high in the area surveyed. 5) 46 percent of farmers changed the blade of rotary implement when they used it over the field capacity of rotary blade of 33 ha which is the area of field for rotary operation per a blade change. 55 percent of farmers changed the rotary blade more than once per two years. 6) The required power for rotary operation of each farm tractors were measured as 17.206 kW at untilled paddy field and 34.989 kW at untilled dry field on the average, respectively. The required power for rotary operation was measured as 28.248 kW on the average at the paddy field which had been plowed once and 28.015 at the paddy field that had rotary tillage operation. Untilled dry field showed the highest value of the required power for rotary operation.

• Korean Journal of Ecology and Environment
• /
• v.51 no.1
• /
• pp.29-39
• /
• 2018

Long-term variation of zooplankton community and species composition was studied from 2003 to 2014 in a deep reservoir, Lake Soyang, in monsoon climate region, Korea. In addition, we examined the correlation with environmental factors. Annual precipitation of watershed showed a large variation in the $705{\sim}1,779mm\;yr^{-1}$ and more than 70% of it was being concentrated from June to September. The water quality of Lake Soyang was shown a clearly seasonal variations and particularly turbid water flowing into the lake during rainy season was the most important environmental factors. Zooplankton community in Lake Soyang showed a significant difference before and after 2006. Zooplankton biomass has shown a large increase and also showed a change in the zooplankton community structure since 2006. The of zooplankton showed positive correlation with temperature and BOD, Chl. a, TP concentration. These results are considered that nutrient and organic matter contained in the turbid water influences the increase in zooplankton biomass and species composition. However, water quality was limited to account for the increase in biomass of zooplankton. For example, increase of small zooplankton density (rotifer; Keratella cochlearis, Polyarthra vulgaris) in spring which is dominated by diatoms (large size; Melosira, Synedra etc.) is considered as a bottom-up effect by the microbial loop. And increased density of crustaceans in autumn was considered a top-down effects by the relationship between predator and prey of microzooplankton and mesozooplankton. In other words the inflow of allochthonous organic matter during rainy season also affected to zooplankton food web in Lake Soyang. In conclusion, biomass, diversity and long-term variations of zooplankton in Lake Soyang were determined by physico-chemical factors but also it is considered that biological interactions is important.

• Korean Journal of Remote Sensing
• /
• v.27 no.3
• /
• pp.235-258
• /
• 2011

The purpose of this study is to investigate climatological variations from the temporal and spatial surface particulate organic carbon (POC) estimates based on SeaWiFS spectral radiance, and to determine the physical mechanisms that affect the distribution of pac in the Gulf of Mexico. 7-year monthly mean values of surface pac concentration (Sept. 1997 - Dec. 2004) were estimated from Maximum Normalized Difference Carbon Index (MNDCI) algorithm using SeaWiFS data. Synchronous 7-year monthly mean values of remote sensing data (sea surface temperature (SST), sea surface wind (SSW), sea surface height anomaly (SSHA), precipitation rate (PR)) and recorded river discharge data were used to determine physical forcing factors. The spatial pattern of POC was related to one or more factors such as river runoff, wind-derived current, and stratification of the water column, the energetic Loop Current/Eddies, and buoyancy forcing. The observed seasonal change in the POC plume's response to wind speed in the western delta region resulted from seasonal changes in the upper ocean stratification. During late spring and summer, the low-density river water is heated rapidly at the surface by incoming solar radiation. This lowers the density of the fresh-water plume and increases the near-surface stratification of the water column. In the absence of significant wind forcing, the plume undergoes buoyant spreading and the sediment is maintained at the surface by the shallow pycnocline. However, when the wind speed increases substantially, wind-wave action increases vertical motion, reducing stratification, and the sediment were mixed downward rather than spreading laterally. Maximum particle concentrations over the outer shelf and the upper slope during lower runoff seasons were related to the Loop Current/eddies and buoyancy forcing. Inter-annual differences of POC concentration were related to ENSO cycles. During the El Nino events (1997-1998 and 2002-2004), the higher pac concentrations existed and were related to high runoffs in the eastern Gulf of Mexico, but the opposite conditions in the western Gulf of Mexico. During La Nina conditions (1999-2001), low Poe concentration was related to normal or low river discharge, and low PM/nutrient waters in the eastern Gulf of Mexico, but the opposite conditions in the western Gulf of Mexico.

• Journal of Korea Water Resources Association
• /
• v.43 no.11
• /
• pp.995-1009
• /
• 2010

Accelerated soil erosion due to extreme climate change, such as increased rainfall intensity, and human-induced environmental changes, is a widely recognized problem. Existing soil erosion models are generally based on the gross erosion concept to compute annual upland soil loss in tons per acre per year. However, such models are not suitable for event-based simulations of erosion and deposition in time and space. Recent advances in computer geographic information system (GIS) technologies have allowed hydrologists to develop physically based models, and the trend in erosion prediction is towards process-based models, instead of conceptually lumped models. This study aims to propose an effective and robust distributed rainfall-sediment yield-runoff model consisting of basic element modules: a rainfall-runoff module based on the kinematic wave method for subsurface and surface flow, and a runoff-sediment yield-runoff model based on the unit stream power method. The model was tested on the Cheoncheon catchment, upstream of the Yongdam dam using hydrological data for three extreme flood events due to typhoons. The model provided acceptable simulation results with respect to both discharge and sediment discharge even though the simulated sedigraphs were underestimated, compared to observations. The spatial distribution of erosion and deposition demonstrated that eroded sediment loads were deposited in the cells along the channel network, which have a short overland flow length and a gentle local slope while the erosion rate increased as rainfall became larger. Additionally, spatially heterogeneous rainfall intensity, dependant on Thiessen polygons, led to spatially-distinct erosion and deposition patterns.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.27 no.5
• /
• pp.599-605
• /
• 2009

Changes of atmospheric pressures cause short- and long-term crustal deformations and thus become error sources in the site positions estimated from space geodesy equipments. In this study, we computed daily displacements due to the atmospheric pressure loading (ATML) at the 14 permanent GPS sites operated by National Geographic Information Institute. And the 10-year GPS data collected at those stations were processed to create a continuous time series of the height estimate. Then, we corrected for the ATML from the GPS height time series to see if the correction changes the site velocity and improves the precision of the time series. While the precision improved by about 4% on average, the velocity change was not significant at all. We also investigated the overall characteristics of the ATML in the southern Korean peninsula by computing the ATML effects at the inland grid points with a $0.5^{\circ}{\times}0.5^{\circ}$ spatial resolution. We found that ATML displacements show annual signals and those signals can be fitted with sinusoidal functions. The amplitudes were in the range of 3-4 mm, and they were higher at higher latitudes and lower at the costal area.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.1
• /
• pp.26-33
• /
• 1998

This experiment was conducted to classify the plant species occurring in the saline reclaimed land by saline tolerance. The vegetation of reclaimed land was composed of various plant species from halophyte to glycophyte showing different saline tolerances. In the investigated saline region, reclaimed land of Youngjong island, Inchun city, 175 species belonging to 32 families were found. Our survey was carried out in two region, having different salinity due to different desalinization. The electricalconductivity (EC) of more saline region showed 48.0mS/cm nd the other region showed 13.0mS/cm. It is assumed that intensity of precipitation and runoff of rainfall may cause salinity gradient in the investigated region. The plant species occurred in the experimental region were classified as 72 species of annual, 42 species of biennial, and 61 species of perennial according to life cycle. For knowing relationship between vegetation of saline region and saline tolerance of occurring species, we tested the saline susceptibility of plant species collected at the saline regions. Testing plants were cultured by nutrient solution containing 200 mM NaCl, the critical concentration of survival in glycophytes. The saline tolerance was graded by the growing capacity in the sand-culture system. The more saline-tolerant species screened by sand culture were Atriplex gmelini, Suaeda asparagoides, Aster tripolium, Suaeda maritima, Salicornia herbacea, and Suaeda japonica. The most saline tolerant family was Chenopodiaceae. Poaceae, Cyperaceae, and Brassicaceae showed relatively high tolerance to saline stress. In the course of growth under the high saline condition, the most noticeable change was the darkening of leaves by increasing of chlorophyll content. The chlorophyll contents were increased with saline stress in most species.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.20 no.4
• /
• pp.29-42
• /
• 2017

As the "Guidelines for GHG Environmental Assessment" was revised, it pointed out that the developers should evaluate GHG sequestration and storage of the developing site. However, the current guidelines only taking into account the quantitative reduction lost within the development site, and did not consider the qualitative decrease in the carbon sequestration capacity of forest edge produced by developments. In order to assess the quantitative and qualitative effects of vegetation carbon uptake, the CASA-NPP model and satellite image spatial-temporal fusion were used to estimate the annual net primary production in 2005 and 2015. The development projects between 2006 and 2014 were examined for evaluate quantitative changes in development site and qualitative changes in surroundings by development types. The RMSE value of the satellite image fusion results is less than 0.1 and approaches 0, and the correlation coefficient is more than 0.6, which shows relatively high prediction accuracy. The NPP estimation results range from 0 to $1335.53g\;C/m^2$ year before development and from 0 to $1333.77g\;C/m^2$ year after development. As a result of analyzing NPP reduction amount within the development area by type of forest development, the difference is not significant by type of development but it shows the lowest change in the sports facilities development. It was also found that the vegetation was most affected by the edge vegetation of industrial development. This suggests that the industrial development causes additional development in the surrounding area and indirectly influences the carbon sequestration function of edge vegetaion due to the increase of the edge and influx of disturbed species. The NPP calculation method and results presented in this study can be applied to quantitative and qualitative impact assessment of before and after development, and it can be applied to policies related to greenhouse gas in environmental impact assessment.