• Journal of Environmental Science International
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• v.19 no.6
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• pp.771-778
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• 2010

The prediction of discharge is very important in water resources management and plan. In this study, we have analyzed discharge data of site at up and down stream in watershed. In order to forecast discharge the regression equations were developed by measuring flow data. Also, to forecast the change of water quality followed by change of inflow the correlation relationship between inflow of the Youngchun site and the Chunhju dam was shown as very high. The forecast of inflow at the Chungju dam would be possible through flow analysis of the Youngchun site. And, it is possible to forecast water quality by flow analysis because the correlation relationship of SS and turbidity followed by change of flow for each station of investigation was very high.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.457-462
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• 2009

In this study, seismic analysis is performed using simplified method, analytical solution and numerical analysis based on one-dimensional seismic site response analysis. The results show that analytical solution of tunnel response is predicted more conservative than numerical solution. And simplified method is not appropriate for seismic analysis of tunnel response. In addition, it is reasonable to determine shear-modulus reduction ratio performing seismic site response analysis to consider ground nonlinear-behavior.

• Journal of electromagnetic engineering and science
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• v.8 no.1
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• pp.1-5
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• 2008

In this paper, a biconical type antenna is proposed for EMI test site validation above 1 GHz. To achieve broadband and omni-directional radiation patterns required by international standard(CISPR), the proposed antenna consists of general bicones with cylindrical loads and adopts side feeding method to minimize the influence on H-plane pattern due to feeding cable, balun, and connector. The radiation patterns of the fabricated antenna are measured and the results are compared with CISPR criteria and commercial antenna in our interest frequencies. Although the proposed antenna has a few problems in frequency range of 1 GHz to 2 GHz, it has relatively better performance than commercial antenna.

• Korean Journal of Hazardous Materials
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• v.3 no.1
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• pp.59-64
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• 2015

Semiconductor industry has large number of chemical inventory and is easily exposed to chemical release incidents. Toxic release is one of the most interested area in evaluating consequence to the vicinity of industry facilities handling hazardous materials. Hydrofluoric acid is one of the typical chemical used in semiconductor facility and is selected and toxic release is evaluated to assess the risk impacted to its off-site. Accident scenarios were listed using process safety information. The scenarios having effect to the off-site were selected and assessed further according to guideline provided by Korea government. Worst case and alternative scenarios including other interested scenarios were evaluated using ALOHA. Each evaluated scenario was assessed further considering countermeasures. The results showed that the facility handling hydroflooric acid is safe enough and needed no further protections at the moment.

• Korean Journal of Materials Research
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• v.20 no.2
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• pp.55-59
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• 2010

$Na^+$ ion conductivity can be improved by the substitution of an Mg atom for an Al atom to form a nonstoichiometric $Na^+$ $\beta$-alumina. We performed a first principles study to investigate the most stable substitution site of an Mg atom and the resulting structural change of the nonstoichiometric $Na^+$ $\beta$-alumina. Al atoms were classified as four different layers in the spinel block that are separated by conduction planes in the nonstoichiometric $Na^+$ $\beta$-alumina. The substitution of an Mg atom for an Al atom at a tetragonal site was more favorable than that at an octahedral site. The substitution in the spinel block was more favorable than that close to the conduction plane. This result was well explained by the volume changes of the polyhedrons, by the standard deviation of the Mg-O distance, and by the comparison with bulk MgO structure. Our result indicates that the most preferable site for the Mg atom was the tetrahedral site at the spinel block in the nonstoichiometric $Na^+$ $\beta$-alumina.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.177-183
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• 2016

The daily report includes the most detailed information and various daily planning and performance data recorded at a site, and includes work types, the number of workers, and the equipment and materials used. However, in the daily reporting process, some information can be omitted or distorted or even made redundant due to there being several steps of manual input. For this reason, the daily report is utilized for a simple report rather than for an appropriate purpose. Thus, to resolve the issues of the existing daily report system mentioned above, a daily report system using a digital pen was developed and then applied to an actual construction site to verify its applicability. As a result, it was found that 96.610% recognition accuracy of handwritten letters could be achieved. In addition, it was no longer necessary to enter the same information multiple times and no additional training or education for using a mobile device was needed. The digital pen-based daily report program developed in this study is expected to contribute to an improvement of information management efficiency and site document management work by addressing the problems of the existing report system.

• Geomechanics and Engineering
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• v.6 no.3
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• pp.293-320
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• 2014

In this study, in order to evaluate adequacy of considering local site effect, excluding soil-structure interaction (SSI) effects in inelastic dynamic analysis and design of mid-rise moment resisting building frames, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with two soil types with the shear wave velocities less than 600 m/s, representing soil classes $D_e$ and $E_e$ according to the classification of AS1170.4-2007 (Earthquake actions in Australia) having 30 m bedrock depth. Structural sections of the selected frames were designed according to AS3600:2009 (Australian Standard for Concrete Structures) after undertaking inelastic dynamic analysis under the influence of four different earthquake ground motions. Then the above mentioned frames were analysed under three different boundary conditions: (i) fixed base under direct influence of earthquake records; (ii) fixed base considering local site effect modifying the earthquake record only; and (iii) flexible-base (considering full soil-structure interaction). The results of the analyses in terms of base shears and structural drifts for the above mentioned boundary conditions are compared and discussed. It is concluded that the conventional inelastic design procedure by only including the local site effect excluding SSI cannot adequately guarantee the structural safety for mid-rise moment resisting buildings higher than 5 storeys resting on soft soil deposits.

• Korean Journal of Construction Engineering and Management
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• v.18 no.5
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• pp.68-76
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• 2017

A recent issue of fine dust is particulate matter with a diameter of less than $10{\mu}g/m^3$. It's classified as a pollutant that has a fatal effect on the human body when inhaled. The fugitive dust must be well controlled, since the adverse effects of dust on the surroundings are increased when the dust is blown away by the wind. Since the construction site is the place where the most fugitive dust is discharged in Korea, managing the fugitive dust discharged from the construction site can be an important issue to solve the problem of domestic fine dust. However, since the construction industry in Korea is the largest in Korea, it is difficult to control the emission of fugitive dust in the domestic construction site. In this paper, we compare and analyze the fugitive dust regulations applied to construction sites in major cities and propose the improvement plans to help control the fugitive dust generated in domestic construction sites.

• Korean Journal of Construction Engineering and Management
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• v.25 no.4
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• pp.15-23
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• 2024

Recently, quality problems, such as the collapse of apartment structures under construction, has emerged as a social issue. Although there are various causes of quality problem and the impact of each problem may be different, the problems from the perspective of construction engineer of construction company are investigated. Therefore, this study aim to investigate the adequacy of construction engineer's experience, number of field engineer, timing of engineer deployment at construction sites, etc. in order to resolve quality and safety problems. In this study, a questionnaire survey was conducted targeting construction managers to obtain objective opinions. The results showed that the number of construction engineers in construction companies should be increased and that intermediate construction engineers should be increased to enable practical site management for resolving quality and safety problems. In addition, it was found that there was a need to reduce the number of non-regular employed field construction engineers in construction site and at the same time systematically regulate the number of on-site construction engineers, similar to safety managers and quality managers.

• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1061-1073
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• 2017

In this study, images were classified using convolutional neural network (CNN) - a deep learning technique - to investigate the feasibility of information production through a combination of artificial intelligence and spatial data. CNN determines kernel attributes based on a classification criterion and extracts information from feature maps to classify each pixel. In this study, a CNN network was constructed to classify materials with similar spectral characteristics and attribute information; this is difficult to achieve by conventional image processing techniques. A Compact Airborne Spectrographic Imager(CASI) and an Airborne Imaging Spectrometer for Application (AISA) were used on the following three study sites to test this method: Site 1, Site 2, and Site 3. Site 1 and Site 2 were agricultural lands covered in various crops,such as potato, onion, and rice. Site 3 included different buildings,such as single and joint residential facilities. Results indicated that the classification of crop species at Site 1 and Site 2 using this method yielded accuracies of 96% and 99%, respectively. At Site 3, the designation of buildings according to their purpose yielded an accuracy of 96%. Using a combination of existing land cover maps and spatial data, we propose a thematic environmental map that provides seasonal crop types and facilitates the creation of a land cover map.