• Journal of the Korean Society of Hazard Mitigation
• /
• v.4 no.3 s.14
• /
• pp.43-50
• /
• 2004

This study had been performed to analyze flushing effects for instantaneous contaminants input with changing dam discharge in River. RMA-2 and RMA-4 models were applied to the downstream part of the Han River(from Jamsil submerged weir to Singok submerged one) The longitudinal dispersion coefficient of $50m^2/s$ was used. The four cases of dam discharges were selected as $500m^3/s,\;1000m^3/s,\;1500m^3/s$ and $2000m^3/s$, respectively, for 1 hour. The drought flow was fixed $200m^3/s$ in the Han River. The arrival time and the concentration of contaminant, the area of dispersion were estimated with RMA-4 model in the downstream part of the Han River. The arrival time which the concentration of contaminants become under 1ppm was analyzed with the stagnant and the instantaneous inflow contaminant at the section of Sungsan Bridge. The more increasing a dam discharge, the more short a dilution time of contaminant. The relation between the dam discharge and dilution time shows linearity. The instantaneous contaminant input was sensitively affected by the dam discharge than the stagnant contaminant one in the river. If it is tried to flush with a temporally increased dam discharge, it should be understood the range of overflowed contaminant dispersion from main channel to tributary channel.

• Water for future
• /
• v.24 no.1
• /
• pp.119-128
• /
• 1991

This study was focused on establishing the concepts of the instream flow to prevent the problems for the conceptual ambiguity and the difference in the instream flow estimation methods. The average drought flow is defined as the flow required to guarantee the minimum function of the river such as prevention of drying. The environmental control flow is defined as the flow required to control optimal river environment, the flow required for navigation, prevention of sea water-intrusion, protection of river management facilities, conservation of water Quality, fishing, prevention of river mouth closure, control of groundwater level, protection of animals and plants, and landscape. The average drought flow was obtained by flow duration analysis for the natural flows in the Han River at Indo-Bridge gaging station. When considering the 9 factors related to environment conservation, the conservation of water quality was proved to be most important. The pollutants for the river flows were estimated and the water qualities were forecasted. After comparing the water qualities in the future and water quality standards, there quired optimal dilution flow was estimated. The average drought flow and environmental control flow are all non-consumptive flows. Therefore larger flow between them, i.e., Max. (average drought flow, environmental control flow) can be the instream flow. The river management flow can be added to the flows for water utilization in the downstream. The results from this study are expected to be very helpful in the systematic river management on the other main rivers in Korea.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.3
• /
• pp.92-103
• /
• 2015

Development of new concrete bridge deck system with FRP plank using as a permanent formwork and the main tensile reinforcement recently has been actively conducted. Concurrent use as a reinforcing material and a permanent formwork, it is possible to reduce the construction time and construction costs than the usual concrete slab. In this study, an experiment was carried out for the bond stress between cast-in-place concrete and the type of FRP plank using as a permanent formwork. The interfacial fracture energy that can be one of the most important parameters were evaluated for adhesion performance and bond stress to know the characteristics of the failure mechanism of the adhesion surface. Interfacial fracture energy of normal concrete is 0.24kN/m of GF11 case, in the case of GF21, 0.43kN/m appears, in the case of CF11 and GF31, 0.44kN/m and 0.46kN/m respectively it appeared. In case of RFCON, 0.52kN/m appears from GF12, the CF12 and GF22, 0.51kN/m and 0.36kN/m appeared each case.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.6
• /
• pp.132-139
• /
• 2017

A huge amount of de-icing agent is sprayed during winter to promote traffic safety in cold regions, and the quantity of de-icing agent sprayed has increased each year. The main ingredients in commonly used de-icing agents are chlorides, such as calcium chloride($CaCl_2$) and sodium chloride(NaCl). While calcium chloride is mostly used in Korea and sodium chloride is usually used in the U.S. and Japan, all de-icing agents include chloride ions. The chlorides included in sprayed calcium chloride-based de-icing agents have severe adverse effects, including the corrosion of reinforcing steels through salt damage by infiltrating into road structures, reduced structural performance of pavement or damage to bridge structures, and surface scaling, in combination with freezing damage in winter, as well as water pollution. In addition, the deterioration of paved concrete road surface that occurs after the use of calcium chloride-based de-icing agent accelerates the development of visual problems with traffic structures. Therefore, the present study was performed to prepare an environment-friendly liquid de-icing agent through a reaction between waste organic acids and calcium-based by-products, which are industrial by-products, and to analyze the properties of the de-icing agent in order to evaluate its applicability to road facilities.

• The Korean Journal of Quaternary Research
• /
• v.20 no.2
• /
• pp.1-10
• /
• 2006

Flooding hazard caused by natural and artificial environmental changes is closely associated with change in river bed configuration. This study is aimed at explaining a river-bed change related to soil erosion in the Keum river basin using GIS and RS. The USLE was used to compute soil erosion rate on the basis of GIS. River-bed profiles stretching from Kongju to Ippo were measured to construct a 3D-geomorphological map. The river-bed change was also detected by remote sensing images using Landsat TM during the period of 1982 to 2000 for the Keum river. The result shows that USLE indicates a mean soil erosion rate of $1.8\;kg/m^2/year$, and a net increase of a river-bed change at a rate of $+5\;cm/m^2$/year in the Kangkyeong area. The change in river-bed is interpreted to have been caused by soil erosion in the downstream of the Keum river basin. In addition river-bed change mainly occurred on the downstream of the confluence where tributaries and the main channel meet. Other possible river-bed change is caused by a removal of fluvial sand aggregates, which might have resulted in a net decrease of exposed area of sediment distribution between 1991 and 1995, while a construction of underwater structures, including a bridge, a reclamation of sand bars for rice fields and dikes, resulted in an increase of the exposed area of river-bed due to sediment accumulation.

• Cartoon and Animation Studies
• /
• s.41
• /
• pp.407-427
• /
• 2015

This thesis is research about the development and application of the panorama image in contemporary artwork, focusing on sculpture and installation. The samples of artworks are a selection of representatives from numerous examples of works that cannot be introduced without exceeding a reasonable scope of the thesis. A brief outline of the historical concepts of the perspective will describe the development of the panorama in itself. Some technical explanations and the practical use of the panorama with its link to 3-dimensional applications should bridge the explanation gap between the 2nd and 3rd dimensional usage of the panorama in contemporary artwork. Furthermore, some philosophical statements are proposed in the discussion. One of the main interests and initial motivation of this study was my personal believe that there is always a relationship between social philosophical values and the way a society sees or encounters visual structures. In other words the contemporary understanding of space and perspective is mirroring the actual zeitgeist and creates an exemplary visual aesthetics.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.5D
• /
• pp.507-517
• /
• 2012

The main purpose of this study is to address flooding resilient land use management strategy based on the distributional characteristics of storm damage areas in Gyeonggi-do. The employed methods are 1) Exploratory Spatial Data Analysis (ESDA) to understand the spatial patterns of storm damage areas occurred from 2005 to 2009, 2) Local Indicator of Spatial Association (LISA) to examine spatial autocorrelation existed in storm damage areas for the year of 2009. The results show that 1) crop land damage is very sensitive to heavy precipitation, 2) damaged buildings are found in all over the Gyeonggi areas, but relatively more damages are in the regions closed to the City of Seoul, 3) damaged roads-bridges, streams, and reaches are found in mostly rural areas, 4) building and crop land damage occurs mostly in lowlands with different spatial patterns. These findings imply that 1) it will be useful to consider the average distances and slopes of damaged building and crop lands from streams for the decision making of land use management strategy, 2) further management efforts are required in the north, east, and south regions of Gyeonggi areas to prevent roads-bridge, stream, and reach damages, 3) the present land use pattern needs to be carefully investigated by considering the damage clustered areas for the year of 2009 based on watershed and municipality boundaries.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1115-1123
• /
• 2008

When constructing projects such as road embankments, bridge approaches, dikes or buildings on soft, compressible soils, significant settlements may occur due to the consolidation of these soils under the superimposed loads. The compressibility of the soil skeleton of a soft clay is influenced by such factors as structure and fabric, stress path, temperature and loading rate. Although it is possible to determine appropriate relations and the corresponding material parameters in the laboratory, it is well known that sample disturbance due to stress release, temperature change and moisture content change can have a profound effect on the compressibility of a clay. The early research of Tezaghi and Casagrande has had a lasting influence on our interpretation of consolidation data. The 24 hour, incremental load, oedometer test has become, more or less, the standard procedure for determining the one-dimensional, stress-strain behavior of clays. An important notion relates to the interpretation of the data is the ore-consolidation pressure ${\sigma}_p$, which is located approximately at the break in the slope on the curve. From a practical point of view, this pressure is usually viewed as corresponding to the maximum past effective stress supported by the soil. Researchers have shown, however, that the value of ${\sigma}_p$ depends on the test procedure. furthermore, owing to sampling disturbance, the results of the laboratory consolidation test must be corrected to better capture the in-situ compressibility characteristics. The corrections apply, strictly speaking, to soils where the relation between strain and effective stress is time independent. An important assumption in Terzaghi's one-dimensional theory of consolidation is that the soil skeleton behaves elastically. On the other hand, Buisman recognized that creep deformations in settlement analysis can be important. this has led to extensions to Terzaghi's theory by various investigators, including the applicant and coworkers. The main object of this study is to suggestion the modified compression index value to predict settlements by back calculating the $C_c$ from different numerical models, which are giving best prediction settlements for multi layers including very thick soft clay.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.6
• /
• pp.541-547
• /
• 2017

Climate change has become the main cause of the exacerbation in natural disasters. Social Overhead Capital(SOC) structure needs to be checked for displacement and crack periodically to prevent damage and the collapse caused by natural disaster and ensure the safety. For efficient structure maintenance, the optical image technology is applied to the Structure Health Monitoring(SHM). However, optical image is sensitive to environmental factors. So it is necessary to verify its validity. In this paper, the accuracy of estimating the vertical displacement was verified with respect to environmental condition such as natural light, measurement distance, and the number of image sheets. The result of experiments showed that the effect of natural light on accuracy of estimating vertical displacement was the greatest of all. The measurement angle which was affected by the change in measurement distance was also important to check the vertical displacement. These findings will be taken into account by applying appropriate environmental condition to minimize errors when the bridge was measured by camera. It will also enable the application of optical images to the SHM.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.4
• /
• pp.412-418
• /
• 2014

In this paper, for better boarding performance and pleasant boarding sensitivity of the ship, comparison and analysis was performed of motion sickness questionnaire with MSI(Motion Sickness Incidence) calculation based on ship motion theory(Strip Method) due to sea condition, incident angle in main sail way, economic speed, and calculation position of the training ship Kaya of Pukyong National University. On theses works, the rougher sea conditions became, the higher total motion sickness rate was occurred. The weights of vertical acceleration and the rates of MSI were higher at the bridge and the accommodation, which were located farther from the center of gravity of the ship. And effects of the vertical acceleration of the ship were increased in rolling then in head sea. In comparison between motion sickness questionnaire with MSI calculation, when the vertical acceleration increased, the motion sickness rate increased. The location to increase vertical acceleration and the location to cause motion sickness were agreed.