• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.4
• /
• pp.345-350
• /
• 1997

Characteristics of electrical conductivity(EC) of seventy one-greenhouse soil located in southern part of Korea were surveyed to obtain the basic information for sustainable management of plastic film house soils. The averaged soil EC were 5.84 and 2.49dS/m for top-and sub-soil, respectively, showing distribution of 11.3% for top-soils and 50.7% for sub-soils within the optimum level of 2.0 dS/m. On the whole, the soils with flowering plants revealed higher EC than those with fruiting vegetables showing 2.75~6.34dS/m for the former and 2.29(sub-soils)~5.13dS/m(top-soils) for the latter. In a view of soil sampling time, the soils at Feb., 1996 marked 4.3~37.7% and 10.3(top-soils)~11.3%(sub-soils) higher EC compared with the soils at Sept. and Dec., 1995, respectively. The linear regression correlation coefficients of soil minerals to EC were in oder of $Mg^{2+}$ > $NO_3{^-}$ > $Cl^-$ > $Ca^{2+}$ > $SO_4{^{2-}}$ > $K^+$ for top-soils and were $Cl^-$ > $SO_4{^{2-}}$ > $NO_3{^-}$ > $Ca^{2+}$ > $Mg^{2+}$ > $K^+$ for sub-soils. In especial, the concentration of soil EC accompanied the increasing population ratio of soil fungi to bacteria and/or actinomycetes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.9 no.3
• /
• pp.169-179
• /
• 2011

There are two types of nuclear reactors in Korea and they are PWR type and CANDU type. The safe management of the spent fuels from these reactors is very important factor to maintain the sustainable energy supply with nuclear power plant. In Korea, a reference disposal system for the spent fuels has been developed through a study on the direct disposal of the PWR and CANDU spent fuel. Recently, the research on the demonstration and the efficiency analyses of the disposal system has been performed to make the disposal system safer and more economic. PWR spent fuels which include a lot of reusable material can be considered being recycled and a study on the disposal of HLW from this recycling process is being performed. CANDU spent fuels are considered being disposed of directly in deep geological formation, since they have little reusable material. In this study, based on the Korean Reference spent fuel disposal System (KRS) which was to dispose of both PWR type and CANDU type, the more effective CANDU spent fuel disposal systems were developed. To do this, the disposal canister for CANDU spent fuels was modified to hold the storage basket for 60 bundles which is used in nuclear power plant. With these modified disposal canister concepts, the disposal concepts to meet the thermal requirement that the temperature of the buffer materials should not be over $100^{\circ}C$ were developed. These disposal concepts were reviewed and analyzed in terms of disposal effective factors which were thermal effectiveness, U-density, disposal area, excavation volume, material volume etc. and the most effective concept was proposed. The results of this study will be used in the development of various wastes disposal system together with the HLW wastes from the PWR spent fuel recycling process.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.1
• /
• pp.78-91
• /
• 2018

In order to understand the distributions of organic matter and heavy metal concentrations in the surface sediment of Jaran Bay, we measured the grain size, total organic carbon (TOC), total nitrogen (TN), and heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn) in surface sediments collected at 15 stations in this bay in November 2014. The sediment consisted of finer sediment such as mud and clay, with 8.6-9.8Ø($9.3{\pm}0.3$Ø) of mean grain size. The concentrations of TOC and TN in the sediment ranged from 1.51-2.39 % ($1.74{\pm}0.22%$) and 0.20-0.33 % ($0.23{\pm}0.03%$), respectively, and did not show spatial difference. The carbon to nitrogen ratio (C/N ratio) ranged from 5-10, indicating that organic matter in the sediment originated from oceanic sources such as animal by-products from fish and shellfish farms. The concentrations of Cr, Fe, and Mn were much higher in the mouth of the bay than in the inner bay, and the concentrations of As, Cd, Cu, Hg, Pb, and Zn showed an opposite distribution pattern. Based on the results of the sediment quality guidelines (SQGs), enrichment factor (EF), geoaccumulation index ($I_{geo}$), pollutant load index (PLI), and ecological risk index (ERI), the surface sediment in Jaran Bay is not polluted or only slightly polluted with Cd, Cr, Cu, Hg, Pb, and Zn, whereas it is moderately to strongly polluted with As. In particular, some regions in the bay were identified as having a considerable risk status, indicating that metal concentration in the sediment could impact benthic organisms. Thus, the systematic management for marine and land sources of organic matter and heavy metals around Jaran Bay is necessary in order to ensure seafood safety and maintain sustainable production on shellfish farms.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.1
• /
• pp.262-268
• /
• 2017

The energy consumption of buildings is approximately 20.5% of the total energy consumption, and the interest in energy efficiency and low consumption of the building is increasing. Several studies have performed energy analysis and evaluation. Energy analysis and evaluation are effective when applied in the initial design phase. In the initial design phase, however, the energy performance is evaluated using general level information, such as glazing area and surface area. Therefore, the evaluation results of the detailed design stage, which is based on the drawings, including detailed information of the materials and facilities, will be different. Thus far, most studies have reported the analysis and evaluation at the detailed design stage, where detailed information about the materials installed in the building becomes clear. Therefore, it is possible to improve the accuracy of the energy environment analysis if the energy environment information generated during the life cycle of the building can be established and accurate information can be provided in the analysis at the initial design stage using a probability / statistical method. On the other hand, historical data on energy use has not been established in Korea. Therefore, this study performed energy environment analysis to construct the energy environment historical data. As a result of the research, information classification system, information model, and service model for acquiring and providing energy environment information that can be used for building lifecycle information of buildings are presented and used as the basic data. The results can be utilized in the historical data management system so that the reliability of analysis can be improved by supplementing the input information at the initial design stage. If the historical data is stacked, it can be used as learning data in methods, such as probability / statistics or artificial intelligence for energy environment analysis in the initial design stage.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.25 no.4
• /
• pp.282-290
• /
• 1992

Based on surplus production models using fishery data for the last 20 years, a stock assessment was conducted for the small yellow croaker in Korean waters. The maximum sustainable yields (MSY) from the Schaefer and Fox models were estimated to be 37,000 metric tons (mt) and 33,450 mt. Zhang's model using time-series biomass with instantaneous coefficients of fishing mortality (F) and using time-series biomass and catch yielded MSY estimates of 45,328 mt and 40,160 mt, respectively. A yield-per-recruit analysis showed that the current yield per recruit of about 20g with F= 1.11 $yr^{-l}$, where the age at first capture $(t_c)$ is 0.604, was much lower than the maximum possible yield per recruit of 43g. Fixing $t_c$ at the current level and reducing fishing intensity (F) from 1.11 $yr^{-l}$ to 0.4 $yr^{-l}$ yielded only a small increase in predicted yield per recruit, from 20 to 25g. However, estimated yield per recruit increased to 43g by increasing $(t_c)$ from the current age (0.604) to age three with F fixed at the current level. This age at first capture corresponded to the optimal length which was obtained from the $F_{0.1}$ method. According to the analysis of stock recovery strategies employing the Zhang model, the optimum equilibrium biomass $(B^*_{MSY})$ which produces the maximum yield could be achieved after approximately five years at the lower fishing intensity (F=0.5).

• Journal of the Korean Institute of Landscape Architecture
• /
• v.45 no.3
• /
• pp.21-29
• /
• 2017

In this study of visitor place attachment to parks, Scannel and Gilford considered the dimensions of place attachment, and proposed the theoretical framework of PPP(Place, Person, Process) that should be systematically studied from the perspective of person, place and psychological processes. According to Scannel's theoretical basis, this paper puts forward the hypothesis of a structure model of place attachment. In the model, the five independent variables of people, places, cognition, emotion, and behavior have influenced the dependent variable of place attachment. The questionnaire was conducted on 18 neighborhood parks in Kunming, China, and the residents of the 5 neighborhood parks in Daejeon, South Korea. A total of 1,645 valid samples of the questionnaire survey were collected. Through confirmatory factor analysis(CFA) results of the inspection of the various elements, it was shown that the reliabilities of 6 latent variables, such as people, places, cognition, affection, behavior and place attachment, which were composed with the observed variables(30 observed variables in Daejeon, 19 observed variables in Kunming), were all above 0.7 and the data were fit for this study. The hypothesis test results found that the physical environment of the neighborhood parks such as a comfortable environment, pleasant road and convenient facilities would increase the rate of visitors coming back. From the park management perspective, to increase the amount of visitors to the park, the park should increase visibility, provide more organized, varied activities and meetings, or special exhibitions according to the particular characteristics of the individual park, to increase awareness of the park. From the park visitors' psychological perspective, visitors are seeking to enjoy the park facilities and environment not only to bring physical relaxation, but also to bring about a psychological cure. With the commonality of attachment structure between the two countries, to improve the place attachment of neighborhood park visitors, collecting regularly visitor feedback will facilitate the sustainable development of neighborhood park attachment.

• Journal of Korean Society of Forest Science
• /
• v.84 no.2
• /
• pp.239-246
• /
• 1995

This research aimed at the contribution to obtaining the scientifical data which were required for planning she environmentally sound and sustainable management, particularly in the field of the logging road construction. Main natural environmental variables including natural vegetation, rainfall, soil runoff were measured in the logging road on-sites and analysed. This project was carried out at the (mt.)Paekunsan Research sorest of Seoul National University, located in Gwangyang, Chollanam-do in southern part of Korea, from 1993 to 1994. 1. The explanatory variables for erosion and sedimentation on logging road surface were accumulated rainfall, erosion distance, cross-sectional gradient, and soil hardness. The erosion and sedimentation on logging road was increasing positively in proportion to the accumulated rainfall, soil distance from starting point of the logging road, and cross-sectional gradient. 2. On cut-slope of logging road, cut-slope shape, part of the slope, plant coverage, soil hardness, sand content, accumulated rainfall, clay content, and silt content were effective factors. Cut-slope erosion and sedimentation on logging roam increased as with the lower plant coverage, the lower accumulated rainfall, the high sand content in the soil. 3. On fill-slope of logging road, there were three significant variables such as total rainfall and number of rainfall-storm. Fill-slope erosion and sedimentation had a positive correlation with the amount of rainfall, the number of rainfall, the soil hardness. 4. The total erosion and sedimentation on logging road were $5.04{\times}10^{-2}m^2/m^2$ in logging road construction year, $7.37{\times}10^{-2}m^2/m^2$ in next year. The erosion and sedimentation on logging road surface were 32.7% of total erosion and sedimentation on Logging road in construction year, and 57.1% in next year, respectively. The erosion and sedimentation on cut-slopes were 30.4% on logging road in construction year, fill-slopes of total erosion and sedimentation and 21.0% in next year, respectively. The erosion and sedimentation on fill-slopes were 36.9% on logging road in construction year, 21.9 in next year. To decrease the erosion and sedimentation at the logging road from the beginning stage of construction, the effective revegetation works should be implemented on the cut-slope and fill slopes, and erosion control measures such as optima. road design must be constructed on read surface.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.252-252
• /
• 2017

Nowadays water shortage is becoming one of the biggest problems in the Korea. Many different methods are developed for conservation of water. Soil water management has become the most indispensable factor for augmenting the crop productivity especially on soybean (Glycine max L.) because of their high susceptibility to both water stress and water logging at various growth stages. The farmers have been using irrigation techniques through manual control which farmers irrigate lands at regular intervals. Automatic irrigation systems are convenient, especially for those who need to travel. If automatic irrigation systems are installed and programmed properly, they can even save you money and help in water conservation. Automatic irrigation systems can be programmed to provide automatic irrigation to the plants which helps in saving money and water and to discharge more precise amounts of water in a targeted area, which promotes water conservation. The objective of this study was to determine the possible effect of automatic irrigation systems based on soil moisture on soybean growth. This experiment was conducted on an upland field with sandy loam soils in Department of Southern Area Crop, NICS, RDA. The study had three different irrigation methods; sprinkle irrigation (SI), surface drip irrigation (SDI) and fountain irrigation (FI). SI was installed at spacing of $7{\times}7m$ and $1.8m^3/hr$ as square for per irrigation plot, a lateral pipe of SDI was laid down to 1.2 m row spacing with $2.3L\;h^{-1}$ discharge rate, the distance between laterals was 20 cm spacing between drippers and FI was laid down in 3m interval as square for per irrigation plot. Soybean (Daewon) cultivar was sown in the June $20^{th}$, 2016, planted in 2 rows of apart in 1.2 m wide rows and distance between hills was 20 cm. All agronomic practices were done as the recommended cultivation. This automatic irrigation system had valves to turn irrigation on/off easily by automated controller, solenoids and moisture sensor which were set the reference level as available soil moisture levels of 30% at 10cm depth. The efficiency of applied irrigation was obtained by dividing the total water stored in the effective root zone to the applied irrigation water. Results showed that seasonal applied irrigation water amounts were $60.4ton\;10a^{-1}$ (SI), $47.3ton\;10a^{-1}$ (SDI) and $92.6 ton\;10a^{-1}$ (FI), respectively. The most significant advantage of SDI system was that water was supplied near the root zone of plants drip by drip. This system saved a large quantity of water by 27.5% and 95.6% compared to SI, FI system. The average soybean yield was significantly affected by different irrigation methods. The soybean yield by different irrigation methods were $309.7kg\;10a^{-1}$ from SDI $282.2kg\;10a^{-1}$ from SI, $289.4kg\;10a^{-1}$ from FI, and $206.3kg\;10a^{-1}$ from control, respectively. SDI resulted in increase of soybean yield by 50.1%, 7.0% 9.8% compared to non-irrigation (control), FI and SI, respectively. Therefore, the automatic irrigation system supplied water only when the soil moisture in the soil went below the reference. Due to the direct transfer of water to the roots water conservation took place and also helped to maintain the moisture to soil ratio at the root zone constant. Thus the system is efficient and compatible to changing environment. The automatic irrigation system provides with several benefits and can operate with less manpower. In conclusion, improving automatic irrigation system can contribute greatly to reducing production costs of crops and making the industry more competitive and sustainable.

• Information Systems Review
• /
• v.11 no.1
• /
• pp.161-179
• /
• 2009

Nowadays an increasing number of Internet users are running individual websites as Blog or Cyworld. As this type of personal media has a great influence on communication among people, business comes to care about Network Effect, Network Software, and Social Network. For instance, Cyworld created the web service called 'Minihompy' for individual web-logs, and acquired 2.4milion users in 2007. Although many people assumed that the popularity of Minihompy, or Blog would be a passing fad, Cyworld has improved its service, and expanded its Network with various contents. This kind of expansion reflects survival efforts from infinite competitions among ISPs (Internet Service Provider) with focus on enhancing usability to users. However, Cyworld's Network Effect is gradually diminished in these days. Both of low production cost of service vendors and the low searching/conversing costs of users combine to make ISPs hard to keep their market share sustainable. To overcome this lackluster trend, Cyworld has adopted new strategies and try to lock their users in their service. Various efforts to improve the continuance and expansion of Network effect remain unclear and uncertain. If we understand beforehand how a service would improve Network effect, and which service could bring more effect, ISPs can get substantial help in launching their new business strategy. Regardless many diverse ideas to increase their user's duration online ISPs cannot guarantee 'how the new service strategies will end up in profitability. Therefore, this research studies about Network effect of Cyworld's 'Minihompy' using System-Dynamics method which could analyze dynamic relation between users and ISPs. Furthermore, the research aims to predict changes of Network Effect based on the strategy of new service. 'Page View' and 'Duration Time' can be enhanced for the short tenn because they enhance the service functionality. However, these services cannot increase the Network in the long-run. Limitations of this research include that we predict the future merely based on the limited data. We also limit the independent variables over Network Effect only to the following two issues: Increasing the number of users and increasing the Service Functionality. Despite of some limitations, this study perhaps gives some insights to the policy makers or others facing the stiff competition in the network business.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.11 no.1
• /
• pp.31-36
• /
• 1982

Sugars and nitrogen contents and physico-chemical properties of ethanol extracts of fresh, dried, and tail ginsengs with different concentrations of the solvent were investigated. The transmittance at 550nm of fresh, dried and tail ginseng extracts (1% D.Wsoln) respectively, and all the extracts were slightly viscous-sticky, brown and pH of 4.8-6.2 Total sugars, sucrose and starch contents of the extracts were decreased with increasing of enthanol concentration as a solvent. Total sugar content of the extracts were decreased in the order of dried, tail and fresh ginseng and sucrose content were decreased in the order of fresh, driedcand tail ginsengs and starch content were decreased in the order of tail, dried and fresh ginsengs. The reducing sugar contents of the extracts were 4.9-3.8 %, 8.6-12.8 % and 7.6-9.1% in fresh, dried and tail ginsengs, respectively. Total nitrogen contents of the extracts were 2.3-4.6% in average and decreased in the order of dried, fresh and tail ginsengs.