• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.3A
• /
• pp.211-219
• /
• 2010

The design concept of high speed railway bridges is applied to a method for increasing the stiffness of existing bridge structures considering the impact factor by a static load. Generally, the process of structural design would be relied upon an advanced foreign technology. However, the dynamic amplification factor (DAF) and dynamic capacity assessment of high speed railway bridges may be conducted essentially a detailed estimation because the resonance phenomenon is affected by the long length (380 m) and high speed (300 km/h) moving of a high speed railway (Korea Train eXpress: KTX). Therefore, this study will be examined the dynamic capacity of the typical PSC Box Girder high speed railway bridge efficiently, and offered the basic information for the reasonable structural design. For this, the static analysis is conducted considering the load line diagram of KTX based upon existing references. In addition, the KTX moving load is transformed into the time series load considering various analytical variables. The time history analysis is assessed reasonable using the transformed time series load. At that time, analytical variables for calculating the time series load are considered loading node distance, time increment and KTX velocity variation etc. The dynamic capacity of the PSC Box Girder high speed railway bridge is examined based upon the FE analysis result systematically. The structural safety is assessed quantitatively in accordance with the related regulation of the inside and outside of the country.

• Analytical Science and Technology
• /
• v.21 no.6
• /
• pp.480-486
• /
• 2008

This paper reports on the monitoring results of some heavy metals (Pb, Cd, As and Hg) in oriental mineral medicines. Levels of Pb, Cd and As were determined using the acid digestion method and ICP-MS. Hg levels were determined using the gold amalgamation method and Automatic mercury analyzer (AMA). The results indicated that, in the case of Pb, 25.81% (24 cases) of the samples were over MRL (5 mg/kg). Pb levels in Calamina, Pumex, and Cinnabaris exceeded MRL (5 mg/kg). In the case of Cd, 9.68% (17cases) of the samples were over MRL (0.3 mg/kg). Cd levels in Calamina, Pumex and Cinnabaris were exceeded MRL (0.3 mg/kg). In case of As, 24.73% (23 cases) of samples exceeded MRL (3 mg/kg). As levels in Calamina, Lithargyrum, Vermilionum, Cinnabaris and Chalcocitum exceeded MRL (3 mg/kg). In the case of Hg, it was shown that the 76.34% (78 cases) of the samples exceeded MRL (0.2 mg/kg). Hg levels in almost all the samples exceeded MRL (0.2 mg/kg). These results led us to recommend that the domestic commercial law to be legislated to ensure the quality estimation and safety of oriental mineral medicines.

• Analytical Science and Technology
• /
• v.22 no.1
• /
• pp.51-56
• /
• 2009

The samples from coastal sand dune stratum in Chollipo were dated by Optically Stimulated Luminescence (OSL) with modified Single Aliquots Regeneration (SAR) method. It is possible to choose the OSL signals by thermal treatments such as preheat and cut-heat in SAR procedure. Preheat and cut-heat of $260^{\circ}C$ for 10 sec $-220^{\circ}C$ for 0 sec, and $270^{\circ}C$ for 10 sec $-270^{\circ}C$ for 10 sec were applied for estimation of equivalent dose of the samples. The OSL signals from different thermal treatment were used for OSL dating. Equivalent dose were estimated with 4 fractionated grain distributions with $75{\mu}m$, $150{\mu}m$ and $200{\mu}m$ sieves with above heating treatments. Consequently, the estimated dose were differently valued in sample sizes and applied heating treatments, different stratum ages were calculated. The ages from radiocarbon dating were compared with the OSL ages. The ages varying with grain sizes produce that the site sampled were formed with mixed soil sources.

• Journal of the Korean Society for Railway
• /
• v.19 no.3
• /
• pp.380-387
• /
• 2016

Considering that the Seoul subway sector is expected to see extension of lines, addition of stations, and changes of operating companies, a review is needed to identify ways to eliminate or minimize financial deficits in its operation. As for deficits from the operation, additional businesses for extra income have been suggested as alternatives, but inasmuch as Western urban development (that of the subway containment area) may not be applicable to Korean settings, a practical alternative is to maximize income by efficient use of rental facilities that are located inside station properties. This alternative requires the estimation of appropriate facility size and rent for each station; few, however, have addressed this topic. At this juncture, this study aimed to draw an equation for estimating the sizes and rents of station properties by reflecting characteristics of lines and locations; a case study was performed for Subway Lines 5 and 6. Analytical findings are that rental facility sizes and rental incomes are affected mainly by the subway ridership and transport revenues, whereas the influence of ground-level commercial activity is relatively weak. A particularly great influence was found to be the value of apartment housing in areas through which the subway lines run. Stations on Line 5, which runs through areas of high-value housing, were assigned smaller facility sizes and higher rents than those on Line 6, which covers areas with relatively low housing value. The equation suggested in this study would make possible more practical feasibility studies when the need arises to estimate sales of new or extended facilities affiliated with stations.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.7
• /
• pp.5009-5014
• /
• 2015

Hydraulic uplift which is caused by the action of pore water pressure can be occurred in clay underlain by granular soil during conducting narrow excavation. Estimation of hydraulic uplift is done by considering soil beam. In order to execute more precise estimation of hydraulic uplift, determination of stress distribution in soil beam is necessary. This study presents stress distribution and displacement distribution in the soil beam based on the theory of elasticity. Stress distribution developed in the soil beam by self weight was derived using stress function depicted by $5^{th}$ order of polynomial and it was seen that vertical stresses along the depth of the soil beam show parabolic distribution and those directions be downward. Regarding soil beam which has the weight of $16kN/m^3, thickness and depth are 1m respectively, maximum vertical stress was about 1.7kPa. Stress distribution by the aciton of pore water pressure was derived via superposition of the stresses corresponding to the self weight and it can be seen that vertical compressive stresses act along the depth of the soil beam when the magnitude of pore water pressure equal to 5 times of the self weight is considered. Equations for prediction of the displacements in the soil beam are also presented.

• Journal of Environmental Impact Assessment
• /
• v.23 no.6
• /
• pp.417-431
• /
• 2014

There is a Conjoint Analysis to estimate the environmental value of natural river restoration project of Inchon Metropolitan City's small River: Gong-chon Stream, Gul-po Stream, Seung-gi Stream, Jang-su Stream. In order to find out the optimal expense condition, we tried to estimate the possible payable amount. According to the analysis, almost all people are willing to pay 15,000 Won. In case of the river types, the people liked 10 cm's depth of water and there should be brook trail, convenient facilities and flood plain at the stream edge space. But it is impossible to build these facilities with minimum fare 15,000 Won per a household. If the necessary expenses set high, the tax resistance of the local residents will be increased. So, in consideration of the analytical results of the attribute level, we draw five alternatives. This study is based on the results of Incheon metropolitan City residents' survey, and there is Conjoint Analysis to estimate the environmental value of natural-type river project of Incheon metropolitan City. If it is reflected the special assume factors of this study, and if there is exact environmental value estimation of the various river quality through different analysis, then it will become a study of high utilizing.

• Journal of Korean Society of Steel Construction
• /
• v.19 no.6
• /
• pp.621-632
• /
• 2007

The purpose of this study was the estimation and formulation of orthotropic flexural rigidities considering the deformed shape for a plate stiffened with rectangular ribs. Analytical results of methods modifying the flexural rigidity of the x-direction, the y-direction or both directions were compared at the center, the x-directional quarter point and the y-directional quarter point of stiffened plates loaded at the center. The composite method modifying the flexural rigidity of both directions improves the accuracy compared with the other methods. Moreover, the ratio of modified coefficients for each directional rigidity can be expressed as a function corresponding to each dimension of stiffened plates. The application of modified coefficient functions to various types of stiffened plates with different boundary conditions, aspect ratios and rib arrangement shows that the increment of the error ratio is small compared with examples of this study and the application of proposed functions shows more accurate results than previous methods modifying the flexural rigidity. Therefore, by using the modified coefficient functions proposed in this study, the orthotropic plate analysis of plates stiffened with rectangular ribs can easily achieve more accurate displacement results.

• Korean Journal of Remote Sensing
• /
• v.32 no.6
• /
• pp.551-566
• /
• 2016

In the satellite remote sensing, the operational environment of the satellite sensor causes image degradation during the image acquisition. The degradation results in noise and blurring which badly affect identification and extraction of useful information in image data. Especially, the degradation gives bad influence in the analysis of images collected over the scene with complicate surface structure such as urban area. This study proposes a multi-stage image restoration to improve the accuracy of detailed analysis for the images collected over the complicate scene. The proposed method assumes a Gaussian additive noise, Markov random field of spatial continuity, and blurring proportional to the distance between the pixels. Point-Jacobian Iteration Maximum A Posteriori (PJI-MAP) estimation is employed to restore a degraded image. The multi-stage process includes the image segmentation performing region merging after pixel-linking. A dissimilarity coefficient combining homogeneity and contrast is proposed for image segmentation. In this study, the proposed method was quantitatively evaluated using simulation data and was also applied to the two panchromatic images of super-high resolution: Dubaisat-2 data of 1m resolution from LA, USA and KOMPSAT3 data of 0.7 m resolution from Daejeon in the Korean peninsula. The experimental results imply that it can improve analytical accuracy in the application of remote sensing high resolution panchromatic imagery.

• Journal of Korea Water Resources Association
• /
• v.53 no.9
• /
• pp.637-646
• /
• 2020

The shallow landslide-trigerred debris flow in hillslope catchments is the primary geological phenomenon that drives landscape changes and therefore imposes risks as a natural hazard. In particular, debris flows occurring in urban areas can result to substantial damages to properties and human injuries during the flow and sediment transport process. To alleviate the damages as a result of these debris flow, analytical models for flow and damage prediction are of significant importance. However, the analysis of debris flow model parameters is not yet sufficient, and the analysis of the entrainment, which has a significant influence on the flow process and the damage extent, is still incomplete. In this study, the effects of erosion and erosion process on the flow and the impact area due to the change in the soil parameters are analyzed using Deb2D model, a flow analysis model of debris developed in Korea. The research is conducted for the case of the Mt. Umyeon landslide in 2011. The resulting impacted area, total debris-flow volume, maximum velocity and inundated depth from the Erosion model are compared to the field survey data. Also, the effect of the entrainment changing parameters is analyzed through the erosion shape and depth. The debris flow simulation for the Raemian and Shindong apartment catchment with the consideration of entrainment effect and erosion has been successful. Each parameter sensitivity could be analyzed through sensitivity analysis for the two basins based on the change in parameters, which indicates the necessity of parameter estimation.

• Korean Journal of Food Science and Technology
• /
• v.51 no.5
• /
• pp.425-431
• /
• 2019

Selected leafy vegetables, widely used for Korean Namul dishes, were heat-treated in different ways and their folate retention was investigated. The Lactobacillus casei method was applied for folate estimation and validated to ensure reliability of analytical data. The folate content in Namul highly varied, from 29.7 to $293.4{\mu}g/100g$, depending on the heating methods and the types of vegetables. Most of the Namul variants showed increased folate content on heat treatment. Frying yielded higher folate retention than the other cooking methods (blanching, steaming, baking, and panfrying), and pig weed showed the highest folate retention (3.3 times, $293.4{\mu}g/100g$). L. casei assay for folate estimation showed 95.7% recovery and relative standard deviations less than 2% for both reproducibility and repeatability, indicating good accuracy and precision. Quality of the folate assay was assured by monitoring a quality control chart and a proficiency test (z-score= -0.1) during the entire of study.