• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.5
• /
• pp.564-570
• /
• 2007

This study investigated the treatment of liquid waste containing highly concentrated iron(III)-ethylenediaminetetraaceticacid (Fe(III)-EDTA) of 70,000 mg/L by an underwater electrical discharge process using low voltage and high current. When AC voltage is applied to the discharging electrode with the other electrode grounded, the temperature of the liquid waste around the discharging electrode rapidly increases, and at the same time, hydrogen and oxygen gases are formed at the electrode as a result of electrochemical reactions. Ultimately, gases formed by vaporization of water and electrochemical reactions cover the electrode. Since the liquid waste is electrically conductive, it elongates the ground electrode up to the border of the gas layer, where electrical discharge occurs. Without hydrogen peroxide, electrical discharge was able to remove about 50% of Fe(III)-EDTA. As the concentration of hydrogen peroxide added increased, the removal efficiency of Fe(III)-EDTA increased. When the molar ratio of hydrogen peroxide to the initial Fe(III)-EDTA was higher than 24.7, more than 80 g of Fe(III)-EDTA was removed with an energy of 1 kWh. A comparison between tungsten and steel electrodes showed that electrode material did not affect the Fe(III)-EDTA removal. In the present underwater electrical discharge process, the removal of Fe(III)-EDTA was completed within 30 min at molar ratios of hydrogen peroxide to the initial Fe(III)-EDTA higher than 24.7.

• Journal of the Korean GEO-environmental Society
• /
• v.16 no.6
• /
• pp.13-22
• /
• 2015

In the current work, a series of three-dimensional (3D) numerical modelling has been performed in order to study the effects of the relative locations of tunnels with respect to the position of pile tips which governs the behaviour of pre-existing, adjacent single piles. In the numerical analyses, several governing factors, such as tunnelling-induced pile head settlements, relative displacements, volume losses, axial pile forces, interface shear stresses and apparent factors of safety have been analysed. When the pile tips are inside the tunnelling influence zone, of which the pile tip location is considered with respect to the tunnel position, tunnelling-induced pile head settlements are larger than the ground surface settlements, resulting in tunnelling-induced tensile pile forces. On the contrary, when the pile tips are outside the influence zone, compressive pile forces associated with downward shear stresses at the upper part of the piles are developed. Based on computed load and displacement relation of the pile, the apparent factors of safety of the piles inside the tunnelling influence zone have been reduced by 36% in average. The shear transfer mechanism based on the relative tunnel locations has been analysed in great detail by considering tunnelling-induced pile forces, interface shear stresses and the apparent factors of safety.

• Korean Journal of Comparative Education
• /
• v.22 no.4
• /
• pp.1-24
• /
• 2012

This comparative study attempts to explore in what politico-social context 'Education Welfare Invest Priority Zone Plan' has been developed and to find politico-social implications of Korean EWIPZP through critically comparing the cases of UK and France. Korean financial crisis brought up the importance of 'Education Welfare' turning into a concrete system, 'EWIPZP' in 2003. This educational welfare policy has expanded since 2005 up to now by the changed name of 'Education Welfare Priority Plan' in 2008, that is structurally different from the original framework which was to support schools in educationally disadvantaged areas. Even the cases of EAZ in UK and ZEP in France started by progressive political parties and established on the ground of 'equity' philosophy, turned into the excellence-based equality policy confronting with the harsh condition of neo-liberalistic global economy under the conservative regime. So does Korea under the critics against this tendency. Comparing Korean case with the cases in UK and France, the current Education Welfare Priority Policy in Korea should be back to the original principle of educational equity and transform into the bottom-up bilateral cooperation model from the top-down model by the authorized party itself in order not to be manipulated politically.

• Journal of the Korea Institute of Construction Safety
• /
• v.1 no.1
• /
• pp.31-39
• /
• 2018

It is reported that about 20 % of all fires in Korea are caused by the electric equipment and installations. In complex and large-scale buildings, the sizes of electric fires are becoming larger as property damage and casualties increase. Among the causes of various electric fires, fire by short circuit accounts for about 71.5% of overall fires, and in the classification by electric equipment and installation, fire caused by wiring and wiring equipment accounts for approximately 38.3% of overall fires. The purpose of this study is to propose methods to prevent electric fires due to short circuit by improving indoor wiring currently in use and to find the fundamental measures to prevent wiring equipment caused fires by improving the socket and plug which are commonly used in wiring equipment. It is expected that the electric fire prevention measures presented through this study can be used as a measure to protect many people and properties by eliminating the root cause of electric fire.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.1
• /
• pp.323-328
• /
• 2019

In order to construct 3D geospatial information about the terrain, current measurement using a total station, remote sensing, GNSS(Global Navigation Satellite System) have been used. However, ground survey and GNSS survey have time and economic disadvantages because they have to be surveyed directly in the field. In case of using aerial photographs and satellite images, these methods have the disadvantage that it is difficult to obtain the three-dimensional shape of the terrain. The terrestrial LiDAR can acquire 3D information of X, Y, Z coordinate and shape obtained by scanning innumerable laser pulses at densely spaced intervals on the surface of the object to be observed at high density, and the processing can also be automated. In this study, terrestrial LiDAR was used to analyze slope displacement. Study area slopes were selected and data were acquired using LiDAR in 2016 and 2017. Data processing has been used to generate slope cross section and slope data, and the overlay analysis of the generated data identifies slope displacements within 0.1 m and suggests the possibility of using slope LiDAR on land to manage slopes. If periodic data acquisition and analysis is performed in the future, the method using the terrestrial lidar will contribute to effective risk slope management.

• 재활복지
• /
• v.17 no.4
• /
• pp.311-338
• /
• 2013

The Act of Disability Discrimination and Rights Restriction was enacted in 2008 states that all services including cultural and artistic activities should be fair and easily accessible for disabled. The aim of this study was to determine how to improve the facilities and services for the disabled in exhibition facilities and provide complementary guidelines for amenities designed for people with disabled. The conclusions identified through this study are as follows: 1) It should be installed pedestrian safe passage so that visitors could access from the entrance of the ground to inside of the exhibition facility. 2) The floor of the exhibition hall should be installed not slip, and dangerous obstacles placed in the corridor should be removed. 3) It Should be considered that visually impaired and wheelchair users are use different facilities at toilet and elevator. 4) To guide the visually impaired and hearing impaired it should be prepared palpable map, braille signage, miniature and brochures. 5) Visually impaired and hearing impaired can experience the exhibits by using a variety of senses, therefore it may need to provide assistive devices and human services.

• Korean Journal of Materials Research
• /
• v.28 no.11
• /
• pp.659-662
• /
• 2018

We report the properties of infrared photodetectors based on two kinds of quantum dots(QDs): i) 2.0 ML InAs QDs by the Stranski-Krastanov growth mode(SK QDs) and ii) sub-monolayer QDs by $4{\times}[0.3ML/1nm\;In_{0.15}Ga_{0.85}As]$ deposition(SML QDs). The QD infrared photodetector(QDIP) structure of $n^+-n^-(QDs)-n^+$ is epitaxially grown on GaAs (100) wafers using molecular-beam epitaxy. Both the bottom and top contact GaAs layers are Si doped at $2{\times}10^{18}/cm^3$. The QD layers are grown with Si doping of $2{\times}10^{17}/cm^3$ and capped by an $In_{0.15}Ga_{0.85}As$ layer at $495^{\circ}C$. The photoluminescence peak(1.24 eV) of the SML QDIP is blue-shifted with respect to that (1.04 eV) of SK QDIPs, suggesting that the electron ground state of SML QDIP is higher than that of the SK QDIP. As a result, the photoresponse regime(${\sim}9-14{\mu}m$) of the SML QDIP is longer than that (${\sim}6-12{\mu}m$) of the SK QDIP. The dark current of the SML QDIP is two orders of magnitude smaller value than that of the SK QDIP because of the inserted $Al_{0.08}Ga_{0.92}As$ layer.

• Korean Journal of Remote Sensing
• /
• v.34 no.6_1
• /
• pp.857-868
• /
• 2018

The microphysics and spatio-temporal distribution of atmospheric aerosols are responsible for estimating the optical properties at a given location. Its accurate estimation is essential to plan efficient simulation for radiative transfer. For this sake, synergetic use of reanalysis data with optics database was used as a potential tool to precisely derive the aerosol model on the basis of the major representative particulates exist within a model grid. In detail, mixing of aerosol types weighted by aerosol optical depth (AOD) components has been developed. This synergetic aerosol model (SAM) is spectrally extended up to $40{\mu}m$. For the major aerosol event cases, SAM showed that the mixed aerosol particles were totally different from the typical standard aerosol models provided by the radiative transfer model. The correlation among the derived aerosol optical properties along with ground-based observation data has also been compared. The current results will help to improve the radiative transfer model simulation under the real atmospheric environment.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.3
• /
• pp.146-159
• /
• 2014

After inspecting ground surface or excavating cultural heritage site, the government can take measures for the preservation of buried cultural heritage based on the related law. It means that the provisions complement the limitation of current cultural heritage management system by extending the scope of cultural heritage to be preserved. But we neither have set any matters about implementing the measures for preservation of the buried cultural heritage, nor manage the heritage and its surroundings after implementing the measures. Due to these insufficiency of the law, there arise several problems in the field. For example, the measures for preservation are not complete, or preserved cultural heritage is damaged due to inappropriate management. We have to resolve the problems in order to accomplish the original purpose of taking measures for preservation of the heritage. First, it is necessary to make sure of the legal status of preserved buried cultural heritage, to establish the standards to decide whether to preserve it or not. We need to have regulations by law or internal rule on the daily management, who should manage it, what and how the manager should manage. It is also important for local residents to take an active part in preserving and utilizing the cultural heritage as the owner. Through building up the foundation mentioned above, the meaning and value of preserved buried cultural heritage can be expanded widely.

• Korean Journal of Heritage: History & Science
• /
• v.51 no.4
• /
• pp.192-207
• /
• 2018

The Hyangwonjeong and Chwihyanggyo located in the back garden of Gyeongbokgung Palace have mainly been investigated by referring to historical records about the reign of King Gojong and various drawings thought to have been made in the late Joseon period. Because the current Chwihyanggyo was rebuilt temporarily after being burned to the ground during the Korean War, its form and the location of its reconstruction are not grounded on any accurate historical investigation. Although there are some photos of the Chwihyanggyo that were taken between the end of the Joseon period and the Japanese colonial era, there is no information about the photographer or when they were taken, and it is hard to see which photos show the original Chwihyanggyo Bridge with them. The Cultural Heritage Administration, which is currently promoting the restoration of the Chwihyanggyo, has recognized this problem and initiated research on the matter. In 2017, an excavation survey successfully identified the original location of the Chwihyanggyo, as well as that of Hyangwonji Gado (假島), and the shape of the first foundation stone in the pier. With these findings it was possible to infer the ways in which the Chwihyanggyo has changed over the years. Moreover, by measuring the AMS (Accelerator Mass Spectrometer) of the samples collected in the mounding layer of the Gado where the Hyangwonjeong is located, it was discovered that the Hyangwonjeong was constructed sometime after the Imjin waeran (Japanese Invasion of Korea in 1592), which means that the theory that 'the late Joseon Hyangwonjeong was not the former early Josenn Chwirojeong' is groundless. Judging by the materials found to date, we can reasonably assume that the Chwihyanggyo and Hyangwonjeong must have been built around the same time that Geoncheonggung Palace was founded in the late Joseon period.