• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.1
• /
• pp.86-98
• /
• 2014

Currently, many OBUs(On Board Unit)s were installed on the vehicle because ETCS(Electronic Toll Collection System) using DSRC(Dedicated Short Range Communication) was constructed in the tollgate of the whole country.A research development and the commercialization utilizing the One Card All Pass and those Infrastructures of ETCS, are promoting of ITS services. Although many studies of the application method about the One Card All Pass of ETCS have been made, standards about the application method of the One Card All Pass and payment for the provision of traffic convenience, were not made clear. So we are proposed method that One Card All Pass announced by Ministry of Land, Infrastructure and Transport, takes advantage of the existing DSRC-based to apply ETCS. We have confirmed the performance of the system through a variety of driving test using three test vehicles on trial operation site and ETCS applying application method proposed in this study. As a result of driving test, we have confirmed validity of standard application method proposed in this study through the communication success rate of about 99% and analyzed problem that may occur by applying service parts of ETCS of transportation convenience facilities because of about 1% communication failure rate.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.1
• /
• pp.39-47
• /
• 2016

Repair methods of aging concrete pavement are generally used composite structure pavements, such a composite structure is subjected to a large impact on the mechanical behavior and ensure long-term commonality integrated under vehicle loads, environmental loads of the public in accordance with the bond strength between old and new concrete. A common of bonded concrete overlays that are currently available is Interface arrangements using a variety of equipment to ensure the excellent bond strength between old and new concrete than standard concrete, mixed with a material such as a polymer in order to improve the adhesion with the material itself. However, these method of constructions are being applied, depending on the developer site presents no special specifications apply when a specific application criteria objectively, this is due to the situation of each individual method, which is based on the difficulty in quality control of the site manager. In this study by performing a field test for polymer content via the variables that contribute most significantly to ensure bond strength and the field element core of the interface processing method and materials to ensure bond strength between the old and the new concrete, it was to derive the construction site construction method that can improve the performance of the bond strength through a review of the construction around the correlations and the bond strength according to the effective performance analysis of the conventional surface treatment process and variation of polymer volume fraction.

• Journal of Korean Society of Transportation
• /
• v.27 no.2
• /
• pp.95-105
• /
• 2009

Traffic accidents on highways are likely to happen when there is an imbalance in the complex relationships among key elements such as road geometries, driver related factors, and mechanical performances. The Demand-Effort Model (DEM), which evaluates highway safety, can be explained by the imbalance, which occurs when the level of demand of the driver's attention to the road environment exceeds that of the response from the driver. This study suggests a new model that improves the reliability of the current DEM through the reinterpretation on the physiological signals with the help of the Neural Network Model (NNM). The data were collected from 149 subjects, who drove a test vehicle on the Yongdong, Honam, and Seohaean Expressways in Korea. Three important results could be drawn from the recursive tests as follows; (1) Only 5 out of 10 parameters on the physiological signals which are currently used were proven to be meaningful through the Normality Test, Cluster Analysis, and Mann-Whitney Analysis. (2) The revised DEM, which internally uses the NNM, showed more reliable results than existing DEM. Group 1, which is based on the new DEM showed 80.0% of accuracy in measuring the level of driver's efforts, however, that of Group 2 based on the current DEM was 74.3%. (3) Field tests on the Honam Expressway showed lower 'type II error' with the new DEM (40.5%) than the old DEM (58.8%). The DEM is designed as a quick and easy way to determine highway safety prior to the minute road safety audit (RSA) by a professional audit team. Then a new DEM, which is based on the NNM, needs to be considered since it showed higher reliability and lower error.

• Journal of Biomedical Engineering Research
• /
• v.24 no.1
• /
• pp.1-8
• /
• 2003

The job of long distance driving is likely to be fatiguing and requires long period alertness and attention, which make considerable demands of the driver. Driving fatigue contributes to driver related with accidents and fatalities. In this study, we investigated the relationship between the number of hours of driving and driving fatigue using heart rate variability(HRV) signal. With a more traditional measure of overall variability (standard deviation, mean, spectral values of heart rate). Nonlinear characteristics of HRV signal were analyzed using Approximate Entropy (ApEn) and Poincare plot. Five subjects drive the four passenger vehicle twice. All experiment number was 40. The test route was about 300Km continuous long highway circuit and driving time was about 3 hours. During the driving, measures of electrocardiogram(ECG) were performed at intervals of 30min. HRV signal, derived from the ECG, was analyzed using time, frequency domain parameters and nonlinear characteristic. The significance of differences on the response to driving fatigue was determined by Student's t-test. Differences were considered significant when a p value < 0.05 was observed. In the results, mean heart rate(HRmean) decreased consistently with driving time, standard deviation of RR intervals(SDRR), standard deviation of the successive difference of the RR intervals(SDSD) increased until 90min. Hereafter, they were almost unchanging until the end of the test. Normalized low frequency component $(LF_{norm})$, ratio of low to high frequency component (LF/HF) increased. We used the Approximate Entropy(ApEn), Poincare plot method to describe the nonlinear characteristics of HRV signal. Nonlinear characteristics of HRV signals decreased with driving time. Statistical significant is appeared after 60 min in all parameters.

• Environmental and Resource Economics Review
• /
• v.20 no.3
• /
• pp.595-628
• /
• 2011

This study investigates the issues and suggests reform measures in applying CV methods to the Korea Development Institute's (KDI's) Preliminary Feasibility Test (PFT) of public projects. Most public projects on culture, science and environment evaluated under the PFT system belong to the category of "nonstandard" projects whose outputs are non-marketed, and CV is currently the main tool used for their benefit estimation. A careful discussion and investigation is recommended for the selection of target population, payment vehicle, and number of payment times. Operating expert reviews, focus group interviews, and pre-tests is highly recommended to reduce the potential bias involved in the CV studies. A single or double bounded dichotomous choice format is the most popular design of questionnaire, but we identify several undissolved issues in designing and implementing the format. Some other forms of inducing WTPs may still deserve our consideration. Various specifications of the WTP function need to be tried and tested based on their stability, in particular. Employing a nonparametric approach is also recommended. Treatments of 0 or negative WTPs and protest bids are shown to be the most serious issues that affect the estimation results significantly. We review diverse measures of handling those issues and summarize their advantages and shortcomings.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.730-736
• /
• 2016

In a previous study, the impact factor response spectrum and corresponding method for evaluating the load carrying capacity of bridges was suggested to improve the existing evaluation method. To verify the applicability of the suggested method, which is based on the frequency of bridges, the dynamic characteristic test for an actual single span simply-supported bridge was conducted. Through a field test under ambient traffic conditions, the dynamic response of the bridge was obtained using wireless accelometers and its fundamental frequency was identified. The peak impact factor was determined from the identified frequency and the impact factor response spectrum. The load carrying performance variation of the bridge was estimated considering the performance reduction factor, which was calculated using the current and previous natural frequency and impact factor. From the result, the load carrying capacity of the bridge was decreased, but the capacity was still enough because its value is greater than the design live load. Through the overall procedures and technical details presented in this paper, the suggested evaluation method can be applied to actual bridges with the acceleration data measured under ambient traffic conditions and the impact factor response spectrum.

• Journal of the Korean GEO-environmental Society
• /
• v.18 no.5
• /
• pp.55-60
• /
• 2017

It is critical for Korea to make effective use of limited space as it has dense population and high traffic volume compared to its terrestrial area. To resolve this issue, diverse types of underground structures have increasingly been applied so far, and one of the most representative structures is double-deck tunnel. It has upper and lower roads separated by middle slab that shows dynamic behavior according to the vehicle and earthquake loads. In case of the characteristics of earthquake response, it is necessary to have exploratory study as it has high loads, complex working mechanism, and difficult theoretical approach. In order to understand the characteristics of earthquake response based on the supporting conditions of middle slab in double-deck tunnel, this study conducts indoor shaking table test with 3 test cases: (1) fix both brackets, (2) free and fix at each bracket and (3) free at both brackets for 2 seismic waves of artificial and Gyeongju earthquake. The result shows if the middle slab is free at both brackets, the acceleration response is reduced 41% for artificial earthquake and 60% for Gyeongju earthquake compared to the one with fix at both brackets.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.10
• /
• pp.499-504
• /
• 2017

A Mobile Radio Wave Measurement System (MRWMS)is a vehicle-mounted system designed to be operating in a single mission. The mission characteristic for mobile measurement requires mobility. For this, we must consider the arrangement and embedded method of MRWMS's antennas. In this paper, we described the measurement method design of direction detecting accuracy for MRWMS and designed the direction finding antenna mast capable of rotating itself by using a slip ring without turntable for Direction Finding (DF) accuracy test. As we removed the dependency of a limited local area by designing a measurement method of direction detecting accuracy, Equipment Under Test (EUT) zero-Adjustment and mounted process shortened. So, we the reduced production costs. We expect an improved cable loss value by shortening the RF cable length in accordance with our design. In addition, due to the same phenomenon, the entire system is lighter and the mobility is improved.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.468-474
• /
• 2019

Korea had the highest accident rate among OECD countries in 2018, with 8.4 per 100,000 population, ranking 4th among 35 countries. In addition, the accident rate of traffic with children and the elderly was also high. This study reviewed the relevant literature and analyzed the traffic-accident analysis system. Customized traffic safety facilities were developed. In addition, by measuring the visibility of the traffic safety facilities by installing a test bed, this study measured the forward driving frequency and vehicle driving speed while driving. As a result of applying the "pedestrian pedestrian model" collision test model, the possibility of serious injury after installing the facility was reduced greatly to 4.6%. In this study, the visibility of traffic safety facilities and the effect of reducing the traffic speed were verified through test beds. Recognizing traffic safety facilities will reduce traffic accidents.

• Journal of Trauma and Injury
• /
• v.25 no.4
• /
• pp.247-253
• /
• 2012

Purpose: Hemorrhage is a main cause of death in trauma patients. The goal of this study is to describe the characteristics of trauma patients with massive bleeding and to evaluate the prognostic factors concerning their survival. Methods: This study was performed retrospectively and included trauma patients with massive bleeding who had been treated from March 2007 to August 2012. The inclusion criterion was patients who received more than 10 U of packed red blood cells within the first 24 hours after visiting the emergency department. Based on their medical records, we collected data in terms of demographic findings, mechanisms of injury, initial clinical and laboratory findings, methods for hemostasis (emergency surgery and/or angioembolization), transfusion, injury severity score (ISS), revised trauma score (RTS) and trauma and injury severity score (TRISS). We used the Mann-Whitney U test and Fisher's exact test to compare the variables between the patients that survived and those that did not. We performed a logistic regression analysis with the significant variables from the univariate test. Results: Thirty-two(32) patients were enrolled. The main mechanisms of injury were falls and motor vehicle accidents. The mean transfusion amount of packed red blood cells (PRBC) was 17.4 U. The mean elapsed time for the first hemostasis (surgery or embolization) was 3.5 hours. The initial technical success rates were 83.3%(15/18) in angioembolization and 66.7%(8/12) in surgery. The overall mortality rate was 34.4%(11/32). The causes of death were bleeding, brain swelling and multiple organ failure. The ISS(25.5 vs 46.3, p=0.000), TRISS(73.6 vs 45.1, p=0.034) and base excess(<-12 mmol/L, p=0.020) were significantly different between the patients who survived and those who did not. Conclusion: The ISS was a prognostic factor for trauma patients with massive bleeding.