• Journal of Environmental Impact Assessment
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• v.10 no.3
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• pp.235-243
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• 2001

Since the middle of 1990s, in Korea a few researches on the optimal management technologies combining numerical model and GIS for the management of water environment in drinking watershed area and reservoir such as Paldang Lake have been carried out. In this study, the integrated water environment management system was been suggested to efficiently reflect the public awareness of the environment by integrating the web based distributed data collection system, GIS, public hearing system and water quality model. As all the components of the system have been developed using the World Wide Web and all data have been collected from the relevant agencies through the Internet, the water quality model could be implemented on the web directly. In consequence, the environmental geographic information in Paldang Lake could be acquired and analyzed through the Internet. The system can rapidly respond to the public right to know on environment, so the public will willingly participate in the governmental projects on environment. To verify the usability of the developed system, it has been applied to Paldang Lake. Especially when the web based model has been used, users can easily and confidentially get the prediction results by applying the minimum number of parameters for the water quality model. This model will provide clearness and scientific bases in the process of water quality prediction for the sensitive sites where there are critical conflicts between the residents and the developers. In this study, rapid water environment management technique without spatial and time limit has been suggested, which can contribute to the efforts on the government and the public participation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.179-187
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• 2010

Corrosion of rebar embedded reinforced concrete is the main cause of collapse and degradation of reinforced concrete structure. Degradation occurs in reinforced concrete structures from corrosion caused by the Chloride that the damage other than the severe degradation of the structure in terms of maintenance and construction when the huge expense required and deciding terms is hard. Therefore, early detection of rebar corrosion is important for efficient maintenance and repairing and planning. Meanwhile, how to evaluate the corrosion of the non-destructive measurements have been used a lot. In particular CM-II (corrosion meter) is used to measurement the natural potential, polarization resistance and the resistivity of the concrete, but has some disadvantages. Embedded mini-sensor has been developed in order to overcome these disadvantages. So Measurement corrosion for using the mini-sensor compares with the measured results CM-II (corrosion meter), the developed mini-sensor verify the validity.

• Geomechanics and Engineering
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• v.20 no.2
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• pp.131-146
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• 2020

Evaluation of earthquake impacts in settlements with a high risk of earthquake occurrence is important for the determination of site-specific dynamic soil parameters and earthquake-resistant structural planning. In this study, dynamic soil properties of Karliova (Bingol) city center, located near to the intersection point of the North Anatolian Fault Zone and the East Anatolian Fault Zone and therefore having a high earthquake risk, were investigated by one-dimensional equivalent linear site response analysis. From ground response analyses, peak ground acceleration, predominant site period, 0.2-sec and 1-sec spectral accelerations and soil amplification maps of the study area were obtained for both near-field and far-field earthquake effects. The average acceleration spectrum obtained from analysis, for a near-field earthquake scenario, was found to exceed the design spectra of the Turkish Earthquake Code and Eurocode 8. Yet, the average acceleration spectrum was found to remain below the respective design spectra of the two codes for the far-field earthquake scenario. According to both near- and far-field earthquake scenarios in the study area, the low-rise buildings with low modal vibration durations are expected to be exposed to high spectral acceleration values and high-rise buildings with high modal vibration durations will be exposed to lower spectral accelerations. While high amplification ratios are observed in the north of the study area for the near-distance earthquake scenario, high amplification ratios are observed in the south of the study area for the long-distance earthquake scenario.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.1-14
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• 2020

The aim of this study is to analyze effects of factors on the number of vehicles involved in traffic accidents on freeway sections. In previous studies about traffic accident severity, the analysis of accidents involving multiple vehicles was insufficient. However, multiple-vehicle accidents are likely to cause casualties and are the main reasons increasing accident duration and social costs. In this study, the number of vehicles involved in an accident was interpreted as the result of the accident, not as the cause of the accident, and the impacts of each accident factor were analyzed using a multinomial logit model. The results indicate that multiple-vehicle accidents are mainly related to following factors: nighttime, driver's faults, obstacles on the road, a downhill slope, heavy vehicles, and freeway mainline sections including tunnels and bridges.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.241-248
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• 2012

This paper presents a reinforced concrete composite column method in order to improve seismic performance of reinforced concrete column specimens by selectively applying steel fiber-reinforced mortars at the column plastic hinge region. In order to evaluate seismic improvement of the newly developed column method, a series of cyclic load test of column specimens under a constant axial load was investigated by manufacturing three specimens, two reinforced concrete composite columns by applying steel fiber-reinforced mortars at the column plastic hinge region and one conventional reinforced concrete column. Both concrete and steel fiber-reinforced mortar was cast-in placed type. From cyclic load test, it was found that the newly developed steel fiber-reinforced columns showed improved seismic performances than conventional reinforced concrete column in controlling bending and shear cracks as well as improving seismic lateral load-carrying capacities and lateral deformation capacities.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.45-53
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• 2020

There is an increasing tendency to try to make predictive analysis using measurement data based on machine learning techniques in the railway industries. In this paper, it was predicted that Track quality index (TQI) using vehicle acceleration data based on the machine learning method. The XGB (XGBoost) was the most accurate with 85% in the all data sets. Unlike the SVM model with a single algorithm, the RF and XGB model with a ensemble system were considered to be good at the prediction performance. In the case of the Surface TQI, it is shown that the acceleration of the z axis is highly related to the vertical direction and is in good agreement with the previous studies. Therefore, it is appropriate to apply the model with the ensemble algorithm to predict the track quality index using the vehicle vibration acceleration data because the accuracy may vary depending on the applied model in the machine learning methods.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.5
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• pp.16-28
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• 2007

In this study, the implications for landscape architecture in the restoration Project of Cheonggyecheon will be shown through the analysis of factors for landscape architect scheme modification. The method of study consists of theoretical study, analysis of the plan and design of landscape architecture of the restoration project of Cheonggyecheon, and deduction of implications thereof. The controversial feints included the many difficulties in realizing the productive design of landscape architecture due to the selective collecting of public opinion and the problems of settling the complications, the design limit of the turnkey and MA systems, the lack of hydraulic knowledge and technology and the shortage of vegetation monitoring data and experimental materials. The alternative proposals are as follows: 1) there should be agreement between the government organization and the civil group, 2) in the turnkey bidding for the river restoration projects, the river restoration design based on the volume divided into some parts should be reconsidered in order to maintain consistency in the total design, 3) in order to maintain consistency in the planning policies, MA designs should also be introduced and applied from the first stage of the project through its completion, and 4) data such as the safe water level in case of flooding for the facilities and the vegetation and data in connection with the ecological restoration of river should be accumulated. If these controversies are not settled effectively, the river restoration project will be delayed due to complications with the citizens and wasted time and effort will result from the frequent design changes. In addition, landscape architecture in this kind of restoration project is bound to decrease in the future due to frequent changes in the hydraulic-centered design.

• Korean Journal of Construction Engineering and Management
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• v.18 no.1
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• pp.83-89
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• 2017

Temporary structures provide the accessible working area when building a permanent building structure in the construction operation. Executed in a natural environment, the temporary structure is prone to the external influence factors of underground water, soil conditions, etc. These factors should be carefully considered in designing the temporary structure. The objective of this study is to apply the external influence factors in designing a more reliable earth retaining wall. The research methodology is based on the Taguchi method that has been studied to improve product quality in the industry. An orthogonal array was developed to analyze the interaction between the external influence factors and the internal influence factors. A sample case study demonstrated that the Taguchi method can be used in planning a more reliable temporary structure for earth retaining walls.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.493-500
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• 2014

This paper presents findings from the assessment of the volcanic ash fragility for multi-hazard resisting vinyl greenhouse and livestock shed among the agricultural facilities. The volcanic ash fragility was evaluated by using a combination of the FOSM (first-order second-moment) method, available statistics of volcanic load, facility specifications, and building code. In this study, the evaluated volcanic ash fragilities represent the conditional probability of failure of the agricultural facilities over the full range of volcanic ash loads. For the evaluation, 6 types(ie., 2 single span, 2 tree crop, and 2 double span types) of multi-hazard resisting vinyl greenhouses and 3 types(ie., standard, coast, and mountain types) of livestock sheds are considered. All volcanic ash fragilities estimated in this study were fitted by using parameters of the GEV(generalized extreme value) distribution function, and the obtained parameters were complied into a database to be used in future. The volcanic ash fragilities obtained in this study are planning to be used to evaluate risk by volcanic ash when Mt. Baekdu erupts.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.1
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• pp.55-62
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• 2007

Recent advances in airborne LiDAR technology allow rapid and inexpensive measurements of topography over large areas. The generation of DTM/DEM is essential to numerous applications such as the fields of civil engineering, environment, city planning and flood modeling. The demand for LiDAR data is increasing due to the reduced cost for DTM generation and the increased reliability, precision and completeness. In order to generate DTM, measurements from non-ground features such as building and vegetation have to be classified and removed. In this paper, a segmented morphology filter was developed to detect non-ground LiDAR measurements. First, segments LiDAR point clouds based on the elevation. Secondly classifies those protruding segments into non-ground points. Those non-ground points such as building and vegetation are removed, while ground points are preserved for DTM generation. For experiments, data sets used in Comparison of Filters (ISPRS, 2003) depicting urban and rural areas were selected. The experimental results show that the proposed filter can remove most of the non-ground points effectively with less commission and omission errors.