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Road surface conditions have a direct effect on the quality of driving, which in turn affects overall traffic flow. Many studies have been conducted to accurately identify road surface conditions using diverse technologies. However, these previously proposed methods may still be insufficient to estimate actual risks along the roads because the exact road risk levels cannot be determined from only road surface damage data. The actual risk level of the road must be derived by considering both the road surface damage data as well as other factors such as speed. In this study, the road hazard index is proposed using smartphone-obtained pothole and traffic data to represent the level of risk due to road surface conditions. The relevant algorithm and its operating system are developed to produce the estimated index values that are classified into four levels of road risk. This road hazard index can assist road agencies in establishing road maintenance plans and budgets and will allow drivers to minimize the risk of accidents by adjusting their driving speeds in advance of dangerous road conditions. To demonstrate the proposed risk hazard assessment methodology, road hazards were assessed along specific test road sections based on observed pothole and historical travel speed data. It was found that the proposed methodology provides a rational method for improving traffic safety., Author(s): Choong Heon Yang (corresponding author) [1]; Jin Guk Kim [1]; Sung Pil Shin [1] 1. Introduction The various defects that frequently occur on roadways can be easily observed while [...]

Bad weather conditions can affect normal driving by substantially hindering visibility. Among all adverse weather conditions, road freezing is probably the most dangerous to drivers because slippery roads reduce surface friction and can lead to loss of vehicle control. This paper evaluates driver preference of receiving real-time road freezing risk information and explores the factors that would most influence drivers' trust in a future road freezing information service. A survey was conducted in the metropolitan areas of South Korea during January and February 2019. The survey was completed by 231 driver's license holders of 18 years or older, and the results were used for statistical analysis. According to the survey results, the variable message sign (VMS) is a very important system from the perspective of public benefit. Car-navigation systems are preferred for age categories of 21∼30 and over 50. In addition, ordinal regression was used to analyze the causal relationship between the level of trust regarding road freezing risk information and its controlling factors. The ordered log odds of drivers with previous accident experience due to slippery roads exhibit a higher level of trust in road freezing risk information because the coefficient is positive. Moreover, drivers with a constant commute time show a lower level of trust in road freezing risk information. These findings provide a foundation for planning the scope of future road freezing risk information service, as well as the specific service targets and type of information, especially during the winter season., Author(s): Moataz Bellah Ben Khedher [1]; Choong Heon Yang (corresponding author) [2]; Jin Guk Kim [2]; Duk Geun Yun [2]; Sung Pil Shin [2] 1. Introduction Adverse weather conditions such [...]

In this paper, a new wireless power and information simultaneous transfer (WPIT) technology based on binary frequency shift keying (2FSK) modulation using the dual bands of a series–parallel combined resonant circuit (SPRC), SPRC-2FSK-WPIT technology, is proposed. Conventional 2FSK-WPIT technologies commonly employ single resonant band, and due to the insufficient utilization of system resonance, they have inherent disadvantages, such as low efficiency and low system quality factor. In the proposed technology, the system employs dual resonant bands of the SPRC and both of the system carriers use the resonant frequencies, and so the disadvantages of the conventional 2FSK-WPIT technology are eliminated. Optimal design of the SPRC-2FSK-WPIT system is conducted. In the optimized system, the two carriers have similar power and information transfer characteristics, and so a high WPIT performance, including stable power transmission, is guaranteed. The proposed technology is validated by experimental results. The experimental prototype shows up to 20 kb/s of communication rate with maintaining the power transfer efficiency over 85% at the distance of 50 mm. [ABSTRACT FROM AUTHOR]

Portable coordinate measuring arm (PCMA) calibration is an efficient way to enhance PCMA accuracy. Optimal test configurations during PCMA calibration are helpful to reduce measuring points and reduce consumption time for calibration. In this paper, a kinematic calibration approach has been proposed for 5DOF PCMA, in which ASME B89.4.22-2004 standard and a self-made ball bar for volumetric calibration test are employed. First, a kinematic error model of PCMA is established, and the error parameters are identified. Second, data processing is carried out based on data obtained from tests including single-point precision calibration test using chamfered hole seat, effective diameter calibration test using the reference spheres, volumetric and distance displacement calibration test using ball bar, and machine coordinate origin determination test using the base plane and base cylinder. Third, the objective function for the identification of kinematic error parameters is established, and it is solved by using Levenberg-Marquardt algorithm. Finally, the results of calibration test are compared with the ANSI/ASME B89.4-2004 performance test. The experimental results show that the single-point repeatability of the machine is reduced 1.1 times and the distance accuracy is enhanced 1.17 times by data processing. [ABSTRACT FROM AUTHOR]