• Archives of design research
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• v.16 no.2
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• pp.209-218
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• 2003

The increase of wheelchair users due to the rapid growth of elderly population, traffic accidents, and industrial disaster etc. becomes a major issue in our society. Thus, the Convenience Promotion Law was enforced to facilitate the use and installation of convenient facilities for the disabled, the elderly and pregnant women. Currently, not only newly built buildings but also roads and parks are accessed and used by all the people without any hindrance. In contrast to this, so far not many studies on residential space design for wheelchair users have been carried out except for public facilities. So, wheelchair users have to bear the inconvenience in their houses made upon the standards of the general people. Therefore, it is necessary to develop design guideline considering the physical characteristics of wheelchair users and their family members to lead a convenient life. This study was conducted in universal design perspective and intended to establish design guideline of convenient residential space for wheelchair users and general people. To accomplish the objective, surveys for wheelchair users' actual conditions and needs, and video observation were carried out.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.108-118
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• 2010

This paper analyzes the changes in rail policy in the UK between 1948 and 2007. The UK rail system, once a nationalized industry, was privatized in 1994. Consequently it increased the role of government after 2000, which was a year of frequent rail accident. Recently the UK rail system has made solving global warming and EU interoperability in rail. This paper examines the main factors in changes in rail policy in the UK, which is through the ruling party's ideology, comprehensive transport policy, aimed at reducing global warming and rail accident. Moreover, this paper clarifies the characteristics of rail policy that is consistent with social role of rail, integrative transport policy and acknowledging the positive role of rail against global warming.

• Tunnel and Underground Space
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• v.12 no.4
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• pp.259-267
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• 2002

Recently, Umbrella Arch Method(UAM) is commonly used in order to enhance the stability of tunnel itself and stabilize the adjacent surface structure. But quantitative estimation of reinforcement effect is needed because UAM is designed and constructed only on the basis of empirical experience. By using 3-dimensional finite element method, parametric study is performed for elastic modulus of ground and overburden, and reinforcement effect is analyzed quantitatively. From the results, surface settlement decreases about 9%∼27% in soil tunnel, about 4%∼24% in weathered rock tunnel and 4%∼17% in soft rock tunnel when applied with UAM. The prediction equation for final surface settlement is suggested through regression analysis and the equation is expressed as exponential function which has variable Smax, unknown coefficient i and k.

• Polymer(Korea)
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• v.31 no.6
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• pp.538-542
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• 2007

This study is on the performance analysis of modified asphalts which were prepared by mixing the asphalt with polymer modifiers of varying compositions which were synthesized by the emulsion polymerization method. Thermal properties of mired asphalt were investigated by DSC (differential scanning calorimetry), and dispersion of modifiers in asphalt was investigated by the fluorescence microscope. Dynamic stability and permanent deformation velocities of mixed asphalt were investigated by wheel tracking measurements. Modifier 6 showed the best results in both penetration test and wheel tracking measurement among investigated modifiers, which supports MMA(methyl methacrylate) moiety in modifiers plays better contribution for the enhancement of asphalt performance than styrene moiety does.

• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.3
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• pp.60-70
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• 1999

The purpose of this study is to analyze the spatial change of water quality pollutant in the upper-stream of Kumho River basin. For this purpose, it compared with ground survey data of water quality measurement, using GIS and Landsat TM image, and then constructed a database of water quality pollutants in the watershed by Arc/Info. Also the land cover classification maps of 1985 and 1997 were prepared using maximum likelihood classification. This study detected and analysed the classified images to produce the area of land cover change per sub-basin. In addition, choropleth maps were prepared with spatial change value of water quality pollutants, and overlay analysis was carried out with weight score for each layer. The results of this study revealed that population, animals and fruit orchards were main factors in the spatial change of water pollution of Kumho River basin. The Comparision of pollutions by sub-basins showed a high pollution value in Daechang-chun and Omok -chun stream which follows through the urban area.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.21-29
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• 2011

This paper presents a method that estimates distance and velocity of an object with reliability regardless of maneuver status of the target in stereo vision system. A stereo vision system can calculate a distance with disparity from left and right images. However, the distance estimation error may occur due to quantization error of image pixel. A sub-pixel interpolation method minimizes the quantization error and estimates accurate disparity with real value. Extended Kalman filter (EKF) was used to minimize the error covariance and estimate the object's velocity. However, divergence problem occurs due to model uncertainty when a target maneuvers highly, which makes the estimation error increase. In this paper, we propose a virtual model extended Kalman filter (VMEKF) method that minimizes the processing time and provides reliable estimation ability regardless of maneuver status. Computer simulations and experimental results in real road environments demonstrate that the proposed method gives a reliable estimation performance and reduces processing time under various maneuver status while comparing other estimation filters.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.88-99
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• 2018

In Korea, there is no clear regulation about right of way (ROW) for personal mobility device (PMD). So it is now illegal to use PMD in a space other than roadway. PMD has an advantage of being able to travel a long distance to move on foot with a relatively high speed, so it seems to spread widely in the near future. In this study, we'd like to establish the permission criteria for PMD in sidewalk, with the performance factors of the PMD. We review the cases of ROW of PMD in some foreign countries, and the performance standards for similar products that are currently allowed to use in the sidewalk or used in the sidewalk. Based on the maintenance standards for the sidewalk, we establish criteria to select the PMD moving means that can be used in sidewalk.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.5
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• pp.531-542
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• 2011

The time-dependent temperature distribution across the section in bridges is determined on the basis of the three-dimensional finite element analyses and numerical time integration in this study. The material properties which change with time and thermal stress of concrete are taken into account to effectively trace the early-age structural responses. Since the temperature distribution is nonlinear and depends upon many material constants such as the thermal conductivity, specific heat, hydration heat of concrete, heat transfer coefficients and solar radiation, three representative influencing factors of the construction season, wind velocity and bridge pavement are considered at the parametric studies. The validity of the introduced numerical model is established by comparing the analytical predictions with results from previous analytical studies. On the basis of parametric studies for four different bridge sections, it is found that the creep deformation in concrete bridges must be considered to reach more reasonable design results and the temperature distribution proposed in the Korean bridge design specification need to be improved.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.2
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• pp.107-118
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• 2018

Due to the rapid economic development, traffic congestion has become a dire concern in Beijing, China. Levying a congestion toll is seen as the most effective solution to the problem. Building a congestion pricing model is a crucial step in implementing a workable toll scheme. Unlike previous attempts, this study not only covers the theoretical discussion but also considers three practical issues: the speed-density relationship, the value of travel time savings, and the determination of optimal traffic volume. We estimate the speed-density relationship by regression models and the value of travel time saved through survey results. We further suggest a way through which the government could identify the optimal traffic flow by a series of trial-and-errors, without the knowledge of exact road demand structure. Finally, a practical tolling scheme is proposed for Beijing's second ring road along with some policy recommendations.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1076-1081
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• 2012

For the purpose of development of the latex suitable for latex modified concrete, experimental researches on the preparation of carboxylated styrene butadiene latex by the method of the two-step emulsion polymerization and application to concrete were performed. Sodium dodecylbenzene sulfonate and sodium salt of lauryl sulfonate were selected as anionic emulsifiers, and nonylphenoxy poly(ethyleneoxy) ethanols (n=10, 20, 40) as latex stabilizer. Potassium persulfate and sodium bisulfite were used as redox initiator, besides $Na_2HPO_4$ and $K_2CO_3$ as electrolytes. Polymerization recipe of latex suitable for latex modified concrete were suggested from the experimental researches on the effects of anionic emulsifiers and their concentration on the polymerization stability, and the effect of electrolytes concentration on the particle size of latex. Physical properties, such as slump, air contents, compressive and flexural strength, of latex prepared by suggested polymerization recipe were examined. The experimental results showed that latex modified concrete satisfied the quality standards in slump and air contents. Furthermore, it was turned out that the compressive and the flexural strength of latex modified concrete with 28 days curing time showed appreciably improvements.