• Korean Journal of Construction Engineering and Management
• /
• v.18 no.2
• /
• pp.38-48
• /
• 2017

Finding causes of workers' unsafe behaviors is important to prevent construction accidents because 80 percent of accidents occur by workers' unsafe behaviors. In this regard, this research aims to investigate possible reasons of workers' unsafe behaviors based on workers' cognitive process model using System dynamics. This study is based on two ways of workers' cognitive process which are in relation to hazard perception and failure of hazard perception. Based on existing literature, causal loops for workers' cognitive process are developed to explain workers' habituation by staying out of accidents, safety learning by experience, failure of hazard perception, and attitude change by accidents. The interactions between the developed loops provide managerial insights to reduce workers' unsafe behaviors from a safety manager's perspective including increasing the probability of workers' hazard perception through knowledge management, maintaining workers' positive attitude toward safety, and controlling first-line supervisors to eliminate workers' unsafe behavior. The research allows us to better understand the causes and solutions of workers' unsafe behaviors in workers' cognitive perspectives.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.33 no.2
• /
• pp.49-57
• /
• 2015

The purpose of this study is to provide the visual landscape modelling on Josun royal tombs and surrounding. The visual landscape of traditional heritage is illustrated by the main view points of analysis. This analysis examines limited view points and cannot reflect a reality of environments. Nowadays various equipments and methodologies are developed for the visual landscape research. This study used new tools for analysis which are Sketch up (3D simulation) and mini helicopter (UAV). With those tools, this research examines not only view points of the analysis but also axis views and disincentive environments as a complex analysis. First of all, the research examined 3D modelling for the virtual simulation and drew coordinates and routes for the UAV operating. Secondly, UAV followed this routes and took linear and continuous views that are real scenes. As a result, it drew 3D simulation could illustrate and control the changing of environments such as the forest density and seasonal variations. Thus, comparing both of them shows efficiently landscape analysis. Thirdly, the study compared virtual and real landscape. Using this 3D modelling, this paper able to elaborate heritage environment and surrounding which omitted by view point analysis. Although this study has limitation practice and exercise on the field, the results and suggestions contribute to the various historic heritage managements and conservations. Moreover, it helps to explain the complex and dimensional landscape analysis.

• The Journal of Engineering Geology
• /
• v.3 no.2
• /
• pp.125-148
• /
• 1993

Groundwater flow in fractured rock masses is controlled by combined effects of fracture networks, state of geostafic stresses and crossflow between fractures and rock matrix. Furthermore the scaie dependent, anisotropic properties of hydraulic parameters results mainly from irregular paftems of fracture system, which can not be evaluated properly with the methods available at present. The basic assumpfion of discrete fracture network model is that groundwater flows only along discrete fractures and the flow paths in rock mass are determined by geometric paftems of interconnected fractures. The characteristics of fracture distribution in space and fracture hydraulic parameters are represented as the probability density functions by stochastic simulation. The discrete fracture network modelling was aftempted to characterize the groundwater flow in the vicinity of existing large cavems located in Wonjeong-ri, Poseung-myon, Pyeungtaek-kun. The fracture data of $1\textrm{km}^2$ area were analysed. The result indicates that the fracture sets evaluated from an equal area projection can be grouped into 6 sets and the fracture sizes are distributed in longnormal. The conductive fracture density of set 1 shows the highest density of 0.37. The groundwater inflow into a carvem was calculated as 29ton/day with the fracture transmissivity of $10^{-8}\textrm{m}^2/s$. When the fracture transmissivity increases in an order, the inflow amount estimated increases dramatically as much as fold, i.e 651 ton/day. One of the great advantages of this model is a forward modelling which can provide a thinking tool for site characterization and allow to handle the quantitative data as well as qualitative data.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.13 no.1
• /
• pp.62-73
• /
• 2010

A bird is needed efficient conservation through habitat management, as the representative of an organism to evaluate the steady of complex ecosystem. So, this study will offer the useful basic data for preserving habitat from now on, as presenting a estimating model with the GIS program which selected factors effecting the habitat of a forest-dwelling bird in Changwon. As the resort of the survey, the number of forest-dwelling birds living in the 135 survey sites were 5 order, 15 family, 26 species and 922 individual. Also, as the result of making habitat analysis into a predict model, 'NDVI', 'Distance to valley', 'Distance to mixed forest' and 'Area of field' were significant and they had R-squares of 51.3%. Next, as the resort of researching the accuracy of Model, it was a reasonable prediction, as the correlation coefficient is 0.735 and MAPE is 20.7%, and a predict map of habitat was made with the model. This map could predict species diversity of no investigated areas and could be an useful basic data for preserving habitat, as an on-the-spot survey.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.13 no.1
• /
• pp.50-61
• /
• 2010

This study was carried out to find out the way to build a comprehensive wetland ecosystem database using the technique of remote sensing and Geographic Information System. A Landsat TM image (taken in Oct. 30, 2002), Kompsat-2 images (Jan. 17, 2008 & Nov. 20, 2008), LiDAR(Mar. 1, 2009) were used for the primary source for the image analysis. Field surveys were conducted March to August of 2009 to help image analysis and examine the results. An actual wetland vegetation map was created based on the field survey. Satellite images were analyzed by unsupervised and supervised classification methods and finally categorized into such classes as Phragmites australis community, mixed community, sand beach, Scirpus planiculmis community and non-vegetation intertidal area. The map of wetland productivity was developed based on the productivity of Phragmites australis and the relationship to the proximity of adjacent water bodies. The developed 3 dimensional wetland map showed such several potential applications as flood inundation, birds flyway viewsheds and benthos distribution. Considering these results, we concluded that it is possible to use the remote sensing and GIS techniques for producing wetland ecosystem spatial database and these techniques are very effective for the development of the national wetland inventory in Korea.

• Journal of the Korean Geosynthetics Society
• /
• v.17 no.1
• /
• pp.127-137
• /
• 2018

Gravel Compaction Pile (hereinafter referred to as GCP) is a ground improvement technique by packing crushed stones on fragile clay ground, pressing it, and forming stakes on the foundation. Although many researchers have analyzed stress behavior of GCP composite ground on domestic GCP technique using laboratory experiment and field experiment, analyses of stress behavior according to the difference of stiffness of mat foundation loaded on the upper foundation of GCP composite ground have not been done actively. Therefore, this study aimed to identify the stress concentration ratio in accordance with the difference of basis stiffness by interpreting figures. To perform this, replacement ratio was changed and modelled using ABAQUS, software for finite element analysis and analyzed the stress concentration ratio, amounts of settlement, and maximum amounts of horizontal displacement of composite ground in accordance with the difference of stiffness. An analysis showed that the stress concentration ratio of rigid foundation was highly assessed than unloading of flexible foundation in case of unloading, while amounts of settlement under flexible unloading condition were slightly higher than under rigid condition. This indicates that the characteristic of stress behavior on the different stiffness of upper foundation needs to be clarified. In addition, the maximum horizontal displacement was generated in a constant level regardless of the difference of stiffness.

• Journal of Soil and Groundwater Environment
• /
• v.14 no.1
• /
• pp.1-10
• /
• 2009

Groundwater flow due to intake of horizontal collector well in riverbank filtration site was analyzed by use of numerical groundwater modeling program (FEFLOW 5.1). Drawdowns of groundwater table nearby collector well were evaluated according to variations of several conditions; pumping rate, thickness of aquifer, offset distance from well to shore line of stream, conductance of streambed. It is observed that the drawdowns of groundwater table are clearly changed according to the variations of these conditions. The results of sensitive analysis shows that the thickness of alluvial aquifer and the offset distance are more sensitive than the conductance of streambed in evaluation of drawdown. This result implies that hydrogeological conditions, as like thickness of aquifer and its distribution in the site are important factors in site selection and evaluating the availability of riverbank filtration intake using horizontal collector well system. It is also revealed that numerical modeling using FEFLOW with 1-D discrete element feature can give efficient quantitative evaluation of horizontal collector well and estimation of availability of riverbank filtration site.

• Geophysics and Geophysical Exploration
• /
• v.14 no.1
• /
• pp.7-17
• /
• 2011

We have developed an inversion code for three-dimensional (3D) resistivity tomography including the anisotropy effect. The algorithm is based on the finite element approximations for the forward modelling and Active Constraint Balancing method is adopted to enhance the resolving power of the smoothness constraint least-squares inversion. Using numerical experiments, we have shown that anisotropic inversion is viable to get an accurate image of the subsurface when the subsurface shows strong electrical anisotropy. Moreover, anisotropy can be used as additional information in the interpretation of subsurface. This algorithm was also applied to the field dataset acquired in the abandoned old mine area, where a high-rise apartment block has been built up over a mining tunnel. The main purpose of the investigation was to evaluate the safety analysis of the building due to old mining activities. Strong electrical anisotropy has been observed and it was proven to be caused by geological setting of the site. To handle the anisotropy problem, field data were inverted by a 3D anisotropic tomography algorithm and we could obtain 3D subsurface images, which matches well with geology mapping observations. The inversion results have been used to provide the subsurface model for the safety analysis in rock engineering and we could assure the residents that the apartment has no problem in its safety after the completion of investigation works.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2005.09a
• /
• pp.93-116
• /
• 2005

SPT-Uphole tomography method was introducedand verified in this paper. In SPT-Uphole method, SPT (Standard Penetration Test) which is common in site investigation, was used as a source and several surface geophones in line were used as receivers. Shear wave velocity (Vs) distribution map which has triangular shape around the boring point can be obtained by tomography inversion. The factors for obtaining reliable result of SPT-Uphole tomography are exact travel time information and accurate inversion method. To establish of the SPT-Uphole tomography procedure, the most reliable method for obtaining exact travel time information and verification of tomography inversion method were studied by using theoretical travel time information and finite element method (FEM) analysis. finally, SPT-Uphole tomography method was performed at the weathered soil site in Kimje. By comparing with several boring data including SPT-N value, feasibility of this method was verified in the field.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.3
• /
• pp.147-154
• /
• 2018

This paper focuses on the development of a support system that can rapidly generate the design data of a hot-form die with cooling channels, commonly known as hot stamping technology. We propose a new process for designing hot-form dies based on our (automated) system, whose main features are derived from the analysis of the design requirements and design process in the current industry. Our design support system consists of two modules, which allow for the generation of a 3D geometry model and its 2D drawings. The module for 3D modeling automation is implemented as a type of CATIA template model based on CATIA V5 Knowledgeware. This module automatically creates a 3D model of a hot-form die, including the cooling channels, that depends on the shape of the forming surface and the number of STEELs (subsets of die product) and cooling channels. It also allows for both the editing of the positions and orientations of the cooling channels and testing for the purpose of satisfying the constraints on the distance between the forming surface and cooling channels. Another module for the auto-generation of the 2D drawings is being developed as a plug-in using CAA (CATIA SDK) and Visual C++. Our system was evaluated using the S/W test based on a user defined scenario. As a result, it was shown that it can generate a 3D model of a hot form die and its 2D drawings with hole tables about 29 times faster than the conventional manual method without any design errors.