• Journal of Korean Society of Water and Wastewater
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• v.17 no.4
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• pp.542-549
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• 2003

In the present study, the feasibility of $UV/H_2O_2$ systems was investigated using low and medium-pressure lamps on biologically treated wastewater effluents for secondary effluent reclamation. Two types of UV lamps were used as the light sources (a 39-W low-pressure mercury lamp and a 350-W medium-pressure mercury lamp). The results from these UV systems showed that the removal of organic compounds could be achieved in the contact time of longer than 30min (i.e., low UV doses). Efficiencies of color removal and disinfection were far better than those of organic matters measured as TOC, DOC and $TCOD_{cr}$. In the low-pressure lamp UV system, it has been found that DOC and color removals were 60.9 and 86.2% with 50mg/L of $H_2O_2$ and contact times of 30 minute, respectively. Whereas, with the medium-pressure lamp UV system, TOC, DOC and color removal were 27.1, 5.6 and 95% with 14.3mg/L of $H_2O_2$ and 14 minute of contact times, respectively. Both systems could be applied for the reclamation of secondary effluent treated with biological treatment processes.

• Journal of Korea Water Resources Association
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• v.50 no.12
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• pp.849-862
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• 2017

The increased frequency of meteorological disasters has been observed due to increased extreme events such as heavy rainfalls and flash floods. Numerous studies using high-resolution weather radar rainfall data have been carried out on the hydrological effects. In this study, a conditional merging technique is employed, which makes use of geostatistical methods to extract the optimal information from the observed data. In this context, three different techniques such as kriging, inverse distance weighting and spline interpolation methods are applied to conditionally merge radar and ground rainfall data. The results show that the estimated rainfall not only reproduce the spatial pattern of sub-hourly rainfall with a relatively small error, but also provide reliable temporal estimates of radar rainfall. The proposed modeling framework provides feasibility of using conditionally merged rainfall estimation at high spatio-temporal resolution in ungauged areas.

• Resources Recycling
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• v.24 no.2
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• pp.29-35
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• 2015

A feasibility test was carried out for upcycling of waste jelly-filled communication cables together with the development of environmentally friendly processes and equipments. High pressure water injection is proved to be an exceptionally environmentally friendly and highly efficient mechanical process. A batch-type cable barking equipment is designed and built on the basis of computational fluid dynamics modelling. It is optimized in terms of energy consumption and productivity with very high copper recovery of 99.5%. Copper nano-powder is prepared by an electrical wire explosion in ethanol media in order to improve the value of final products, and the preliminary economical assessment is also conducted.

• Smart Structures and Systems
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• v.17 no.2
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• pp.167-194
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• 2016

This paper investigates the Synergetics based Damage Detection Method (SDDM) for frame structures by using surface-bonded PZT (Lead Zirconate Titanate) patches. After analyzing the mechanism of pattern recognition from Synergetics, the operating framework with cooperation-competition-update process of SDDM was proposed. First, the dynamic identification equation of structural conditions was established and the adjoint vector (AV) set of original vector (OV) set was obtained by Generalized Inverse Matrix (GIM).Then, the order parameter equation and its evolution process were deduced through the strict mathematics ratiocination. Moreover, in order to complete online structural condition update feature, the iterative update algorithm was presented. Subsequently, the pathway in which SDDM was realized through the modified Synergetic Neural Network (SNN) was introduced and its assessment indices were confirmed. Finally, the experimental platform with a two-story frame structure was set up. The performances of the proposed methodology were tested for damage identifications by loosening various screw nuts group scenarios. The experiments were conducted in different damage degrees, the disturbance environment and the noisy environment, respectively. The results show the feasibility of SDDM using piezoceramic sensors and actuators, and demonstrate a strong ability of anti-disturbance and anti-noise in frame structure applications. This proposed approach can be extended to the similar structures for damage identification.

• Spatial Information Research
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• v.19 no.6
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• pp.1-10
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• 2011

The evaluation systems on the National Spatial Information Policy(NSIP) has been changed, since the Establishment and Use of the National Geographic Information System Act(NGIS Act, 2000) was abolished and the National Spatial Data Infrastructure Act(NSDI Act, 2009) was enacted. As compared to the NGIS Act, the policy evaluation systems for National Spatial Information are regarded as unified and centralized. However, some argue that the claim of budget and the legal feasibility of the NSIP was weakened. Given the different views on the two laws, this study aims at analyzing the changes in the evaluation system by comparing the NGIS Act and the NSDI Act. A Comparative Analysis framework is employed. The subjects of the comparative analysis are evaluation mechanism, evaluator, evaluation target and range, after-assessment utilization, and agent. In order to improve the effectiveness of the evaluation system, it is recommended that the clarification of evaluation purposes, institutional enhancement for evaluation agency, the development of evaluation indexes, the combination of top-down approach and bottom -up approach, and the increased linkage between budget and evaluation result.

• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.64-76
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• 2011

The current development trend and status of a personal air vehicle, known as the novel concept of a transportation that combines a personal car with a light general aviation aircraft, is summarized to investigate its feasibility as a future transportation. In the paper, the development programs of a personal air vehicle such as AGATE, PAVE, SATS and NGATS are first summarized, and then the design, technical development and testing activities of Terrafugia's Transition and Moller International's M400 Skycar, which will be commercialized in a short time, are reviewed. Based on the assessment of technical issues with those vehicles, the key technologies for the future development of the personal air vehicle are suggested with two basic requirements of safety and mobility.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.5
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• pp.495-501
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• 2016

This study applied close-range digital photogrammetry to measure deformation of reinforced-soil wall as the passed time. We proposed to utilize the photogrammetric-board to determine 3D coordinates and compute exterior orientation parameters from the images without measuring control points. The displacements by the proposed method are compared with those of the Total-station. As results, measuring errors was within 5cm, and the deformation was not occurred in the 3 months. The proposed method using the photogrammetric-board therefore can be utilized to measure deformation of the reinforced-soil wall.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.261-269
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• 2002

The objectives of this paper are to study the use of geotextile tribes for dewatering high water content sludges and sediments and to evaluate their feasibility and affecting fsctors. To accomplish these objectives, pressure filtration tests were conducted on woven geotextile (Geotex$\circledR$ 46T and 1212T) fir high water content materials with a modified experimental apparatus. Test results indicate that 1) the filter cake formed on the inside of the geotextile tube is the major contributor to the retention of fine particles, but also causes a decrease in permeability, 2) controlling the formation of the filter cake and thus achieving a balance between soil retention and permeability is vital to a successful project, and 3) geotextiles, sludge properties, and filtration pressures have some effects on the dewatering efficiency and dewatering rate.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.192-204
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• 2012

For a severe accident of nuclear power plant, an approach to estimation of the radiological source term using a severe accident code(MELCOR) has been proposed. Although the MELCOR code has a capability to estimate the radiological source term, it has been hardly utilized for the radiological consequence analysis mainly due to a lack of understanding on the relevant function employed in MELCOR and severe accident phenomena. In order to estimate the severe accident source term to be linked with the radiological consequence analysis, this study proposes 4-step procedure: (1) selection of plant condition leading to a severe accident(i.e., accident sequence), (2) analysis of the relevant severe accident code, (3) investigation of the code analysis results and post-processing, and (4) generation of radiological source term information for the consequence analysis. The feasibility study of the present approach to an early containment failure sequence caused by a fast station blackout(SBO) of a reference plant (OPR-1000), showed that while the MELCOR code has an integrated capability for severe accident and source term analysis, it has a large degree of uncertainty in quantifying the radiological source term. Key insights obtained from the present study were: (1) key parameters employed in a typical code for the consequence analysis(i.e., MACCS) could be generated by MELCOR code; (2) the MELOCR code simulation for an assessment of the selected accident sequence has a large degree of uncertainty in determining the accident scenario and severe accident phenomena; and (3) the generation of source term information for the consequence analysis relies on an expert opinion in both areas of severe accident analysis and consequence analysis. Nevertheless, the MELCOR code had a great advantage in estimating the radiological source term such as reflection of the current state of art in the area of severe accident and radiological source term.

• Journal of Information Technology Services
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• v.11 no.4
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• pp.25-37
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• 2012

In recent year, the u-City construction projects which integrate IT technology into urban infrastructures are being pushed forward by many local governments. These projects contain various purposes in an aspect of regional economy : to reinforce a competitiveness of region by increasing efficiency of urban managements and to revitalize regional economy by stimulating the regional high-tech industries that related to u-City construction. In this context, regional economic impact assessment of u-City construction projects is particularly important because, it give us information about effectiveness of u-City construction policy as a stimulus of regional high-tech industries and the policy feasibility of u-City construction projects that can be a base of public projects. However, it is challenging to assess the impact of u-City projects on regional economy properly due to a lack of understanding about industrial classification, and specific industrial inputs related to u-City construction. In this study, we suggest u-City industrial classifications, and specific-industrial inputs induced by u-City construction projects based on associated legislations, business report for a u-City construction, and results from previous studies. Using these classification and industrial input, we also investigate the regional economic impacts of a u-City construction project in Wha-sung and Dong-tan cities employing Input-output analysis. The empirical results suggests that u-City industries have relatively high in production inducement, and value added inducement compared to input of other industrial sectors. These results indicate that regional economic impact of a Wha-sung and Dong-tan u-City construction project are relatively high, but economic impacts of u-City construction projects vary according to the regional industrial structure, and the specific expense accounts of u-City construction projects.