• Journal of the Korea Organic Resources Recycling Association
• /
• v.9 no.2
• /
• pp.77-86
• /
• 2001

As construction and expansion of wastewater treatment works is continuing, generation of sludge is increasing. Bur most sludge is not used appropriately but disposed by landfill dumping to sea. Furthermore direct landfilling of sludge cake containing moisture content over 75% has been legally prohibited since 2001 that's enforcement will be more strict in 2003. Such a situation means nowadays recycling of organic waste such as sludge and food waste is necessary. Composting is one of recycling methods commonly and used as an effective means of stabilizing organic waste and then compost can be used as fertilizer. However fertilizer law management which include standard of compost products and other fertilizers applied all sludge products indiscriminiately and was not flexible. So MOE has graded organic composts according to land applications to improve recycle of organic wastes. The classified organic compost which contains low contaminants has been possible to use as various purpose. This study enalyzed 30 samples which were raw materials for compost and compost products management well and to estimate the quality of compost products. Heavy metals were measured in Raw materials and OM/N, NaCl and VS were tested in compost products as well as heavy metals. As a result, approximate 10% of raw materials was not suitable to the grade A and 6.7% over the grade B of the regulation on raw materials for compost. In the case of 30 produced compost propducts approximate, 57% of composts was not compatible with the grade A and B of the regulation on composting product. The qualities of compost products were worse than raw materials, because the compost products have more regulation item raw materials have.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.10 no.6
• /
• pp.155-163
• /
• 2010

The past researches on flood inundation simulation mainly focused on development of numerical models based on unstructured mesh networks to improve model performances. However, despite the accurate simulation results, such models are not suitable for real-time flood inundation forecasting due to a huge computational burden in terms of geographic data processing. In addition, even though various types of vector and raster data are available to be compatible with flood inundation models for post-processes such as flood hazard mapping and flood inundation risk analysis, the unstructured mesh-based models are not effective to fully use such information due to data incommensurability. Therefore, this study aims to develop a raster-based two-dimensional inundation model; it guarantees computational efficiency because of direct application of DEM for flood inundation modeling and also has a good compatibility with various types of raster data, compared to a commercial model such as FLUMEN. We applied the model to simulate the BaekSan levee break in the Nam river during a flood period from August 10 to 13, 2002. The simulation results showed a good agreement with the field-surveyed inundation area and were also very similar with results from the FLUMEN. Moreover, the model provided physically-acceptable velocity vectors with respect to inundating and returning flows due to the difference of water level between channel and lowland.

• Journal of Korea Water Resources Association
• /
• v.53 no.2
• /
• pp.89-96
• /
• 2020

Water management agencies under the Ministry of Environment produce and accumulate qualified basic data for major rivers. However, the integrated management of the river water has been weak since the artificial water circulation process, such as the intaking and drainage of agricultural water, has not been examined in the basin, which includes many agricultural land. In this study, a study was conducted on how the power usage method (operating time method) based on the running time can be applied and improved among indirect flow rate measurement methods used to investigate flow rates collected by the riverside for agricultural water purposes, and thus the resultant data of high reliability can be obtained at low cost. The operation time method is suitable for small-scale water pumping stations where it is difficult to secure real-time power supply data. The reliability of the data was verified through the correlation analysis with the actual flow rate, and it was found that the flow rate calculated by the operation time method reflecting the level of the stream to which the inlet of the pumping station is connected can be reasonably matched with the actual flow rate. In addition, it was confirmed that the investment cost at the time of initial installation of the facility was highly efficient by generating qualified flow data at low cost through comparison with direct flow rate measurement methods. If flow data is secured by applying the operation time method to large and small water farms located along the riverside, it is expected that more quantitative and integrated stream water management will be possible.

• Journal of Digital Convergence
• /
• v.16 no.4
• /
• pp.195-203
• /
• 2018

This study was conducted to investigate the types and methods of dental impression materials used in dental clinics in south Korea, the questionnaire was surveyed by a self-administered method for one dentist in a one dental clinic, the collected data were statistically analyzed using SPSS 20. The most frequently used addition silicone impression materials were used in most dental treatment. It was confirmed that the method of taking impression materials having different flow properties(light body and heavy body) was most preferred at one time, also, the implant impression taking method was the most preferred for two rubber impression materials with different flow properties, both direct and indirect. There were statistically significant differences in age and clinical experience between the methods of impression taking of casting restorations and prosthetic according to general characteristics. These results are expected to be helpful for the development of theoretical and practical work based on the basic data for impression material development and research and the preference of impression materials required for dental professional in clinical practice.

• Korean Journal of Agricultural Science
• /
• v.42 no.1
• /
• pp.15-22
• /
• 2015

This study was conducted to evaluate the phytotoxicity of imazosulfuron+fentrazamide mixture in rice field. It is recommended that safe herbicide application was obtained at 3 cm of transplanting depth and in sandy loam or loam soil type. In the direct water seeding of rice, imazosulfuron+fentrazamide SC should be applied at least 10 days before sowing land ower than 25+100 g ai/ha. In case of imazosulfuron+fentrazamide SC application after sowing, If we use the herbicide 15 days after sowing, no herbicide symptoms will be detected even though the amounts of the herbicide increase. In the rice transplanting, it is recommended that imazosulfuron+fentrazamide GR is applied 5 days after transplanting. In case of sequential herbicide application, the imazosulfuron+fentrazamide SC application at 75+300 g ai/ha 15 or 20 days after transplanting after the application at 25+100 g ai/ha or 50+200 g ai/ha 3 days before sowing increases weed control efficacy and gives no phytotoxicity in the rice growth.

• Progress in Medical Physics
• /
• v.19 no.1
• /
• pp.42-48
• /
• 2008

Bio-implantable devices such as heart pacers, gastric pacers and drug-delivery systems require power for carrying out their intended functions. These devices are usually powered through a battery implanted with the system or are wired to an external power source. This paper describes an inductive power transmission link, which was developed for an implantable stimulator for direct stimulation of denervated muscles. The carrier frequency is around 1MHz, the transmitter coil has a diameter of 46mm, and the implant coil is 46mm. Data transmission to the implant with amplitude shift keying (ASK) and back to the transmitter with passive telemetry can be added without major design changes. We chose the range of coil spacing (2 to 30mm) to care for lateral misalignment, as it occurs in practical use. If the transmitter coil has a well defined and reliable position in respect to the implant, a smaller working range might be sufficient. Under these conditions the link can be operated in fixed frequency mode, and reaches even higher efficiencies of up to 37%. The link transmits a current of 50 mA over a distance range of 2-15 mm with an efficiency of more than 20% in tracking frequency. The efficiency of the link was optimized with different approaches. A class E transmitter was used to minimize losses of the power stage. The geometry and material of the transmitter coil was optimized for maximum coupling. Phase lock techniques were used to achieve frequency tracking, keeping the transmitter optimally tuned at different coupling conditions caused by coil distance variations.

• Journal of the Korean Geographical Society
• /
• v.41 no.6 s.117
• /
• pp.701-713
• /
• 2006

This study considers the case when a district with a high development possibility is set up as a regulation region. Initial assumption is that there would be regulation resistance in and around the regulation region. Pyeongchang is taken as a study areas, performing necessary analysis of environment regulation and regulation resistance based upon spatial analysis with the use of GIS. The research proceeding steps are as follows. After examining Pyeongchang present environment regulation state, environment regulation map is constructed, and classification of Pyeongchang's relatively development possibility level map is made. Using this regulation map and development possibility level map, relative regulation resistance level is measured. The results that the rates of Pyeongchang environment regulation region in its present state was higher than Namhan river basin's regulation region rates. Also, overlapping a high development possibility level region with an environment regulation region, the analysis results give reasons to expect high level of regulation resistance in Doam-myeon and Jinbu-myeon in small town units. The analysis of Pyeongchang new buildings locations with regard to environment regulation showed intensive distribution in the regulation region with high development possibility level and adjacent areas (about 66% of new buildings are distributed within 500m range from regulation region). Such results show that the local administration and existing environment regulation policy, not capable of offering direct benefit to the population, are having immanent problems in environment sustainable development and connected with it environment harm causation.

• Journal of Environmental Policy
• /
• v.8 no.1
• /
• pp.49-72
• /
• 2009

To analyze the direct and indirect $CO_2$ emission structure according to industries in Korea, a hybrid IO table quantifying the section of energy in the IO table is needed. However, the results of the recent researches revealed differences in the total amount of $CO_2$ emission by researchers in addition to significant standard deviation in industrial distribution. This study intends to make comparative analysis of the existing method of making an IO table for energy and environment and presents an improvement scheme to contribute to an improvement in calculation of the total amount of $CO_2$ emission and estimation of the emission by industries in Korea. For this purpose, division was made into use as raw materials of energy and that as fuel and a new hybrid IO table was made by removing confounding factors caused by the product tax and subsidies. As a result, the oil and coal industry emitted 5.2 times less $CO_2$ after removing energy inputted as raw materials from the transaction table than before. The amount of $CO_2$ emission estimated by using the IO table based on basic price was found to be 2.7% less than by using the IO table based on the producer price.

• Journal of the Korean earth science society
• /
• v.32 no.6
• /
• pp.525-536
• /
• 2011

In any applications using various types of spatial data, it is very important to account for the scale differences among available data sets and to change the scale to the target one as well. In this paper, we propose to use a geostatistical downscaling approach based on vaiorgram deconvloution and block simulation to generate fine-scale categorical thematic maps from coarse-scale fraction data. First, an iterative variogram deconvolution method is applied to estimate a point-support variogram model from a block-support variogram model. Then, both a direct sequential simulation based on area-to-point kriging and the estimated point-support variogram are applied to produce alternative fine-scale fraction realizations. Finally, a maximum a posteriori decision rule is applied to generate the fine-scale categorical thematic maps. These analytical steps are illustrated through a case study of land-cover mapping only using the block fraction data of thematic classes without point data. Alternative fine-scale fraction maps by the downscaling method presented in this study reproduce the coarse-scale block fraction values. The final fine-scale land-cover realizations can reflect overall spatial patterns of the reference land-cover map, thus providing reasonable inputs for the impact assessment in change of support problems.

• Journal of The Korean Association For Science Education
• /
• v.39 no.6
• /
• pp.755-765
• /
• 2019

This study aims to develop the scales to measure the innovation configurations of Science. Technology, Engineering, Art and Mathematics (STEAM) from the perspective of elementary school teachers and investigates the effect of the innovation configurations and related environmental factors on the usage levels of STEAM based on the newly developed scales for the innovation configurations of STEAM. The scales for the innovation configurations of STEAM are based on analyzing the various previous studies and in-depth interviews and consist of four sub-configurations: The 'Preparation,' 'Design,' 'Implementation,' and 'Evaluation.' The innovation configurations of STEAM was investigated with the developed scales through 266 teachers who are leading STEAM school teachers, are involved in STEAM research group, or are implementing STEAM in general schools. The final 19 questionnaires for the scale of the innovation configuration of STEAM are confirmed with exploratory factor analysis and reliability analysis. In order to examine the relationship between the innovation configurations and levels of use, the direct relationship between four sub-configurations and the usage levels of STEAM and the effect of environmental factors on the innovation configuration and the usage levels of STEAM have been conducted and their interactions are considered. The results show that 'Implementation' in the innovation configurations of STEAM and 'STEAM training experience' are most important factors to improve the usage levels of STEAM for elementary school teachers. It implies that the scales are very helpful in improving as well as figuring out the current innovation configurations of STEAM.