• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.230-237
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• 2000

The wheel bearing in vehicles has been improved to unit module by joining a bearing to a hub in order to achieve weight reduction and easy assembly. Currently, the contact force between a raceway and balls of a bearing is applied as the external force in order to analyse the structure of the unit type bearings. In this paper, simplified boundary conditions are discussed for structure analysis of wheel bearing unit. From the procedure, the contact conditions of balls and race in wheel bearing unit are considered as equivalent non-linear spring elements. The end node of a spring element is constrained in displacement. And the external force of boundary conditions is applied at the contact point between tire and road. For the evaluation of this analysis, its results for the force of spring elements are compared with contact forces of calculated results. and also maximum equivalent stresses of analysis are compared with results of test at the flange of inner ring. The analysis results with proposed boundary conditions are more accurate than results from analysis which is generally used.

• Asian Journal of Atmospheric Environment
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• v.4 no.1
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• pp.9-19
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• 2010

The size distribution of airborne particulate matter (PM) and the concentrations of associated metallic elements were investigated in a busy urban region of a typical Korean industrial city. The PM concentrations measured during the spring, except for those in the size range of 1.1 to 2.1 ${\mu}m$, were slightly higher than the PM concentrations in the summer. Coarse particles contributed greatly to the variation in PM concentrations in the spring, while fine and submicron particles contributed largely to the variation in PM concentrations in the summer. The difference in size modes of the PM concentrations between spring and summer may be explained by the Asian dust effect and its accompanying wind direction and speed. Extremely high enrichment factors (EFs) values (6,971 to 60,966) for all of the size distributions in PM were identified for cadmium (Cd). High EFs values (12 to 907) were also identified for other heavy metals including Cr, Cu, Ni, Pb, Zn and Mn. Low EF values (0.29 to 8.61) were identified for Ca, K, Mg and Na. These results support the common hypothesis that most heavy metals in ambient PM have anthropogenic sources and most light metals have crustal sources. The results of principal components analyses and cluster analyses for heavy metals indicate that the principal sources of PM and metals were emissions from non-ferrous metal smelters, oil combustion, incinerators, vehicular traffic and road dust.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.107-114
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• 1995

To assess the contribution of automobile exhaust to indoor and outdoor levels of $NO_2$ around a major trunk road in Tokyo, $NO_2$ levels of 200 homes were measured at living rooms, kitchens and outdoor at each season, from the summer of 1990 to the spring of 1991, $NO_2$ level was measured for four days using diffusion $NO_2$ dosimeter. Outdoor $NO_2$ levels at each season and indoor $NO_2$ levels at seasons when heaters were not used decreased according to the distance from the roadside. The differences between $NO_2$ levels at zone I(within 20m from the roadside) and zone III(beyond 50m) was about 3 ppb. Automobile exhaust seemed to contribute to this difference. At seasons when heaters were used, indoor $NO_2$ levels of the homes equipped with vented heater, decreased according to the distance from the roadside. However, there was no correlation between indoor levels and the distance from the roadside at homes equipped with unvented heater.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.143-148
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• 2009

The pedestrian space of the street is one of the most important public places in the city. Sidewalks are the paths that everyone travels, and the spaces in which everyone comes together. By Whatever means they travel, everyone is ultimately a pedestrian during their journey through the residential area. Every year, more than six thousand Koreans are victimized by traffic accidents, and a half of them are pedestrians. This study aims at improving the pedestrian environment in residential area, and thus making road a walkable, pedestrian-friendly space. The study reviews the problems in the pedestrian environment of residential area and proposes improvement strategies.

• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1028-1040
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• 2000

A numerical method is presented for the dynamic analysis of military tracked vehicles of high mobility. To compute the impulsive dynamic contact forces which occur when a vehicle passes on a ground obstacle, the track is modeled as the combination of elastic links interconected by pin joints. The mass of each track link, the elastic elongation of a track link between pin joints by the track tension, and the elastic spring effects on the upper and lower surfaces of each track link have been considered in the equations of motion. And the chassis, torsion bar arms, and road wheels of the vehicle are modeled as the rigid multi bodies connected with kinematic constraints. The contact positions and the contact forces between the road wheels and track, and the ground and the the track are simultaneously computed with the solution of the equations of motions of the vehicle consisting of the multibodies. The iterative scheme for the solution of the multi body dynamics of the tracked vehicle is presented and the numerical simulations are conducted.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1542-1549
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• 2011

The Transitional zone between bridge abutment and earthwork is one of the representative vulnerable zones in railway where differential settlements may take place due to the different supportive stiffness. Although transitional zones are managed with stricter standards than those of the other earthwork zones either in the design and construction stages, it is very difficult to prevent differential settlement perfectly. A three-dimensional numerical analyses were performed by applying train moving load in this study. The analytical model including abutments and earthwork zones was constituted with rail, sleepers, track concrete layer (TCL), hydraulic stabilized base (HSB), reinforced road bed, and road bed using railway and road base structure. The clamp connecting the rail and sleeper were also modeled as the element with spring coefficient. The train wheel is modeled in the actual size and moved on the rail with 300 km/hr speed. The deformation characteristics at each point of the rail and the ground were considered in detail when moving the train wheel. The analysis results were compared with those from the two-dimensional analysis without considering moving load. The research results show that displacement and stress were greater in the three-dimensional analysis than in other analyses, and the three-dimensional analysis with moving load should be performed to evaluate railway performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3767-3781
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• 1996

Generally, dynamic loads are applied to real structures. Since the analysis with the dynamic load is extremely difficult, static loads are utilized by proper conversions of the dynamic loads. The dynamic loads are usually converted ot static loads by safety foactors of experiences. However, it may increase weight and decrease reliability. In this study, a method is proposed for the conversion process. An equivalent static load is calculated ot generate a same maximum displacement. The method is verified through numerical tests on a spring-mass systems of one and multi degrees-of freedom. It has been found that the duration time of the loads and the natural frequencies of the structures are critical in the conversion process. A road arem is a self-propelled howizer is selected for the application of the proposed method. The shape of the road arm is optimized under the converted static loads.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.205-209
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• 2005

A traditional settlement, in a long history establishment, is appeared to be configured of the people and their life in the areas. This is, a positive aspects, compared to most of the city in these day which is monotonous aspects. The purpose of this research deals what is the formation process and spatial character in urban settlement of Naju city, and how to applicate in a modern city context. For the research goals, it analyse an old Naju Castle area, transformation of the land use through the cadastral survey, and spatial character through step by step in chronical approach. The process of change can be seen in the devide pattern in a lot, formation and extension of a private road, and formation and change of the road; This shows how to changes traditional settlement in a old urban areas of Naju city. A now road system in old area, as a conflict, push the change of the spatial organization, and the balance of the identity of a traditional settlement and a new change as a convenient needs, it is a key point to get ideal settlement.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 1996.11a
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• pp.95-101
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• 1996

The purpose of this study is to research the residents' subjective opinion the apartment noise. To attain this purpose. we investigated 182 residents' responses at “Da” apartment in Chonju. . Analysis showed the following results. The residents which are living in the building next to the road strongly felt the external traffic noise. The residents living on the first to fifth above the sixth to fifteenth also are suffering from the internal noise. Generally speaking. the apartment residents' life are considerably disturbing with noises. Especially this disturbance was serious in summer.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.226-230
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• 2008

The purpose of this study is to analyse the pedestrian environment of the residential area in residential development. The result of the research are follows; first, the pedestrian environment in the apartment quarter is better than independent residential quarter. second, the pedestrian and the automobile use together the street, because the side walk ist not established from the road where the width is narrow. finally, the condition of side walk paving ist bad, so that the pedestrian environmental level decreased badly