• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.1-8
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• 1995

In the companion paper of the present paper, a coast down test method to determine the resistance forces on running vehicle based on the distance-time measurement was explained along with the suggestions to improve its accuracy and testing methodology. In the present paper some of the suggestions discussed previously are implemented and actually road tested to see the applicability of the improved method(short distance method) in the field. From the results. it is shown that the short distance method which requires only 600m long proving ground road gives at least comparable results on the accuracy compared to the original S-t method which requires 2000m. It is hoped that the present method be further refiend to give more accurate results.

• Particle and aerosol research
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• v.7 no.1
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• pp.21-30
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• 2011

The spatial distributions of air pollutants, in particular, ultrafine particles near traffic congestion roads at urban areas need to reduce human exposure levels for protecting public health. In this study, the number concentrations of ultrafine particles larger than 5 nm were measured every second during driving on the major roads of Nowon-gu, Seoul for 1.6 h using a mobile emission laboratory on October 5, 2010. The ultrafine particle number concentrations ranged from 7,009 to $265,600particles/cm^3$ with an average of $55,570particles/cm^3$, and these levels were comparable to concentrations of ultrafine particles larger than 3 or 7 nm on the arterial roads at urban areas in Los Angeles, USA and Zurich, Switzerland. It was frequently observed that the ultrafine particle number increased rapidly when vehicle speed was accelerated and it decreased sharply when vehicle speed was decelerated. The high peak events of ultrafine particle concentration larger than $200,000particles/cm^3$ were observed seven times during the measurement period. From the three repeated measurements during the short period of 50 min, it was concluded that the ultrafine particle number concentration on the road was significantly time-dependent. This on-road measurement approach can be utilized to manage vehicle-related air pollution in urban.

• Current Optics and Photonics
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• v.3 no.5
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• pp.415-422
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• 2019

Retroreflection of vehicle headlights, as induced by spherical glass beads, is a key optical phenomenon that provides road-surface markings with greatly enhanced visibility, thus better securing a driver's safety in the nighttime as well as in unclear daytime. Retroreflectance of glass beads is a quite sensitive function of their refractive index, so that measurement of the refractive index of glass specifically in the shape of spherical beads needs to be performed within a reasonable uncertainty that is tolerable for road-marking applications. The Becke line method has been applied in assessing refractive index of such glass beads as e.g. an industrial standard in the Republic of Korea; however, the reference refractive-index liquids are not commercially available these days for refractive index greater than 1.80 due to the toxicity of the constituent materials. As such, high-refractive-index glass beads require an alternate method, and in this regard we propose a practically serviceable technique with uncertainty tantamount to that of the Becke line method: Based on comparison of calculated and measured retroreflectance values of commercial glass beads, we discover that their refractive index can be determined with reasonable precision via the retroreflectance measurement. Specifically, in this study the normalized retroreflectance originating from a single glass sphere is computed as a function of refractive index using the Fresnel equations, which is then validated as coinciding well with retroreflectance values measured from actual specimens, i.e. glass-bead aggregates. The uncertainties involved are delineated in connection with radius and imperfections of the glass beads.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.77-84
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• 2017

Recently, interest in safety has been increasing in every area, especially in the field of transportation. The accurate evaluation of the stability of road facilities is needed to improve the level of safety in the field of transportation and the application of new technologies is required to reduce the number of natural disasters. In this study, the wind data were compared and analyzed according to the type of measurement, and an evaluation of the stability of road signs using the wind data was conducted. In addition, a stability plan to secure road signs was elaborated and its effect on the wind load was analyzed. It was found that the wind data measured by a mobile atmospheric observing system (MAOS) was 2.43 times bigger than that measured by the Korea meteorological administration (KMA) and road weather information system (RWIS). In terms of their stability, the road signs were susceptible to failure caused by gusty winds and it was found necessary to ensure their stability. In the future, it will be possible to evaluate the stability of road facilities using road line weather data and the application of wind load reduction technologies is expected to improve road safety.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.19 no.3
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• pp.1-13
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• 2023

Hydronic heated road pavement (HHP) systems have been well established and documented to provide road safety in winter season over the past two decades. However, most of the systems run on asphalt, only a few are tested with concrete, and there rarely is a comparison between those two common road materials in their performance. The aim of this study is to investigate the thermal performance of the concrete HHP systems, including surface temperature variations of experimental pavements in winter season. For preliminary study a small-scale experimental system was installed to evaluate the heat transfer characteristics of the concrete HHP in the test field. The system consists of 3 concrete slabs made of 1 m in width, 1 m in length, and 0.25 m in height. In these slabs, circulating water piping was embedded with different pipe depths of 0.08 m (Case A), 0.12 m (Case B), and 0.20 m (Case C) and same horizontal space of 0.16 m. Heating performance in winter season was tested with different inlet temperatures of 25℃, 30℃, 35℃ and 40℃ during the entire measurement period. Overall, the surface temperature of the concrete HHPs remained above 3℃ in all experimental conditions applied in this study. The results of the surface temperature measurement with respect to the pipe depth showed that Case B was the highest among the three cases. However, the closer the circulating water pipe was to the pavement surface, the greater the heat exchange rate. This results is considered that the heat is continuously accumulated inside the pavements and then the temperature inside the pavements increases, while the amount of heat dissipation decreases as the temperature difference between the inlet and outlet of circulating water decreases. In this preliminary test the applicability of the concrete HHP on road deicing was confirmed. Finally, the results can be used as a basis for studying the effects of various variables on road pavements through numerical analysis and for conducting large-scale empirical experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1720-1723
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• 2003

Recently, as the road capacity reaches a limit and environmental problems becomes serious, there exists a gradually increased need for railway vehicles that are environment-friendly, punctual, reliable and safe. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. Korean High Speed Train has been developed for last 6 years to satisfy the need. Authors developed a measurement system for on-line test and evaluation of performances of Korean High-Speed Train. The measurement system is composed of software part and hardware part. Perfect interface between multi-users is possible. A new method to measure temperature was applied to the measurement system. By using the system, measurement and evaluation of the mechanical characteristics of motors and main transformers in Korean High Speed Train was conducted during test running. The measured results for the temperature characteristics of electric devices verify that the measurement system is accurate and reliable.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.133-134
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• 2008

• 한국도로학회:학술대회논문집
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• 2005.11a
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• pp.331-336
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• 2005

• International Journal of Highway Engineering
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• v.19 no.1
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• pp.29-36
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• 2017

PURPOSES : This study mechanically analyzed the performance of road substructures with focus on infiltration trenches of pavement substructures. METHODS : Water contents and response times for precipitation of pavement substructures were investigated via sensors buried near the infiltration trench to measure water contents. RESULTS : The results of the water contents of pavement systems constructed with an infiltration trench yield levels that were slightly increased by approximately 2% compared to those measured from general pavement systems. This water content difference of 2% resulted in a decrease in service life of less than two years. CONCLUSIONS : Service life reduction due to an infiltration trench is minimal, particularly when the trench is installed with proper caution.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.197-203
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• 2003

Korea Highway Corporation(KHC) began the ambitious KHC Test Road construction project from 1997. It is 7.7km long two-lane highway next to the mainline of Jungbu Inland Expressway. The KHC Test Road construction was completed at the December 2002. It is composed of twenty-five PCC test pavement sections. Section design parameters are (1) concrete slab thickness, (2) base type, (3) base thickness (12, 15, and 18cm), and (4) pavement type. Twenty-five PCC test pavement sections contain 1241 sensors to evaluate the behavior of pavement system under traffic load and environmental change. The behavior of pavement systems will be identified by the observation of sensor measurement and pavement distress survey from test pavement sections. The Test Road research outcome will validate the Korean Pavement Design Guide which is develop by on-going funded research from the Ministry of Construction and Transportation.