• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.299-310
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• 2022

The ability of an automated driving system is based on vehicle sensors, judgment and control algorithms, etc. The safety of automated driving system is highly related to the operational status of the road network and compliant road infrastructure. The safe operation of automated driving necessitates continuous monitoring to determine if the road and traffic conditions are suitable and safe. This paper presents a node and link system to build a road monitoring system by considering the ODD(Operational Design Domain) characteristics. Considering scalability, the design is based on the existing ITS standard node-link system, and a method for expressing the monitoring target as a node and a link is presented. We further present a technique to classify and manage hazard risk into five levels, and a method to utilize node and link information when searching for and controlling the optimal route. Furthermore, we introduce an example of system implementation based on the proposed node and link system for Sejong City.

• Journal of Internet of Things and Convergence
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• v.9 no.1
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• pp.65-70
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• 2023

In this paper, we propose an autonomous driving system using an end-to-end model to improve lane departure and misrecognition of traffic lights in a vision sensor-based system. End-to-end learning can be extended to a variety of environmental conditions. Driving data is collected using a model car based on a vision sensor. Using the collected data, it is composed of existing data and data with outlayers removed. A class was formed with camera image data as input data and speed and steering data as output data, and data learning was performed using an end-to-end model. The reliability of the trained model was verified. Apply the learned end-to-end model to the model car to predict the steering angle with image data. As a result of the learning of the model car, it can be seen that the model with the outlayer removed is improved than the existing model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.297-308
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• 2023

Displacement of structures is the most important parameter for safety and performance assessment and is measured to use for diagnosis and maintenance of bridges. Usually LVDT, Laser and GNSS are used for displacement measurement but these measurement instruments have problems in terms of field condition and cost. Therefore, in this study, displacements were evaluated using rotational angle measured by inclinometers and the proposed algorithm was experimentally verified. As the result, vertical displacements of cable supported bridges with traffic and temperature load were properly evaluated through the proposed algorithm. Therefore it is considered that the proposed algorithm can be used for displacement measurement by vehicle load test and long term displacement monitoring.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.221-239
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• 2022

Various elements such as geometry, traffic safety facilities, congestion level, weather, etc., need to be appropriately reflected in the assessment scenario evaluating the driving safety of automated vehicles. Therefore, this study first established a scenario structure and defined the layer of elements, to derive the elements to be reflected in the automated driving safety evaluation. After that, all elemental candidates that can be reflected in each layer were derived by reviewing the relevant literature. Finally, as a result of an expert survey, 77 items were selected to be reflected in the automated driving safety evaluation. The selected elements are expected to be actively utilized in developing scenarios for the driving safety evaluation of automated vehicles in simulation, proving ground, and real road assessments.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.11-20
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• 2023

The cost of medical treatment for motor vehicle accidents is increasing every year. In this study, we created a model to predict long-term hospitalization(more than 18 days) among minor patients, which is the main item of increasing traffic accident medical expenses, using five algorithms such as decision tree, and analyzed the factors affecting long-term hospitalization. As a result, the accuracy of the prediction models ranged from 91.377 to 91.451, and there was no significant difference between each model, but the random forest and XGBoost models had the highest accuracy of 91.451. There were significant differences between models in the importance of explanatory variables, such as hospital location, name of disease, and type of hospital, between the long-stay and non-long-stay groups. Model validation was tested by comparing the average accuracy of each model cross-validated(10 times) on the training data with the accuracy of the validation data. To test of the explanatory variables, the chi-square test was used for categorical variables.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.8
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• pp.2253-2280
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• 2024

In the upcoming era of transportation, a groundbreaking technology, known as vehicle-to-everything (V2X) communication, is poised to redefine our driving experience and revolutionize traffic management. Real-time and secure communication plays a pivotal role in V2X networks, with the decision-making process being a key factor in establishing communication and determining malicious nodes. The proposed framework utilizes a directed acyclic graph (DAG) to facilitate real-time processing and expedite decision-making. This innovative approach ensures seamless connectivity among vehicles, the surrounding infrastructure, and various entities. To enhance communication efficiency, the entire roadside unit (RSU) region can be subdivided into various sub-regions, allowing RSUs to monitor and govern each sub-region. This strategic approach significantly reduces transaction approval time, thereby improving real-time communication. The framework incorporates a consensus mechanism to ensure robust security, even in the presence of malicious nodes. Recognizing the dynamic nature of V2X networks, the addition and removal of nodes are aligned. Communication latency is minimized through the deployment of computational resources near the data source and leveraging edge computing. This feature provides invaluable recommendations during critical situations that demand swift decision-making. The proposed architecture is further validated using the "veins" simulation tool. Simulation results demonstrate a remarkable success rate exceeding 95%, coupled with a significantly reduced consensus time compared to prevailing methodologies. This comprehensive approach not only addresses the evolving requirements of secure V2X communication but also substantiates practical success through simulation, laying the foundation for a transformative era in transportation.

• Journal of agricultural medicine and community health
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• v.20 no.2
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• pp.157-168
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• 1995

This study was carried out, through analyzing the annual reports(year of 1973-1993) on health status of Su Dong-Myun, and specific survey data of 332 households(Su Dong-Myun 209, Byul Nae-Myun 123), located in Nam Yang Ju-Si, Kyung Gi-Do, from July 20 to July 31, 1995, to find out more effective means for primary medical care in a rural area. The results were as fellows : 1. Number of population in Su Dong-Myun was 5,419 in 1973, 4,591(the lowest) in 1987 and 5,707 in 1995. In the composition rate of population, "0-14" of age group showed markedly decreasing tendency from 43.1% in 1975, to 19.1% in 1995, however "65 and over" markedly in creasing tendency form 5.3% in 1975 to 9.8% in 1995. 2. Annual utilization rate per 1,000 inhabitants in Su Dong-Myun showed markedly increasing tendency from 1973 to 1977 such as 343 in 1973, 540 in 1975, 900 in 1977. However, since 1979, the rate showed rapidly decreasing tendency, such as 846 in 1979, 519 in 1985, 190 in 1991 and 1993. 3. The morbid household rate per year was 53.6% of respondents and the rate per 15 days was 48.2%. In disease classification rate of morbid household per year, Arthralgia & Neuralgia was the highest rate(33.9%) and gastro-intestinal disorder(19.3%), Cough(11,9%), Hypertension(7.8%), Accident(3.2%) in next order. 4. In the utilizing facilities for Primary Medical Care, Medical facilities was showed the highest rate(58.1% of respondents) and Pharmacy and Drug Shp(33.1%), Tradition Method(4.0%) in next order. In the Medical facilities, General private clinic was showed the highest rate(34.3%) and specific private Clinic(22.3%), Hospital(19.0%), Health (Sub)center(16.3%), Nurse practitioner (3.3%), Oriental hospital and clinic(2.7%) in next order. 5. Experience rate, utilizing health subcenter was 51.8% of the respondents, and it was 55.0% in Su Dong-Myun and 46.3% in Byul Nae-Myun. In utilization times of health subcenter, times-rate showed next orders such as 1-2 times/6months(31.6%), 1-2 times/year (22.1%), 1-2 times/months(19.2%), 1-2 times/3months(15.6%). 6. In objectives, visiting Health Subcenter, Medical Care was the highest rate(59.8% of the respondents) and health control(23.3%) was in next order. In Medical Care, Primary Care by general physician was higher rate(51.1%) almost all. In the Health control, Immunization too was high rate(18.0%) in health control activities. 7. The reasons rate, utilizing health subcenter showed next order, such as distance to Medical facilities(33.0% of the respondents), Medical Cost(28.1%), Simple process of consultation (10.8%), Effectiveness of cure(7.6%), Function of primary medical care(7.0%) and Attitude of physician(6.5%). 8. In the affecting factors to utilization of primary medical facilities, medical needs was showed the highest rate(29.5% of the respondents) and medical cost(15.4%), distance to medical facilities(14.2%), traffic vehicle(14.2%) and farm work(6.9%) in next order. 9. In the priority between 'daily farm work,' and 'primary medical care', only 46.4% of respondents answered that primary health care is more important than the daily farm work The 22.6% of respondents answered 'daily farm work', and the 12.3% answered 'the equal of the both'. 10. In the criterion of medical facilities choice, medical knowledge and technical quality was showed the highest rate(56.3%), distance or time to medical facilities(10.9%), sincerity and kindness of physician(9.4%), medical cost(8.7%) and traffic vehicle(6.5%) in next order 11. In the advise for improvement of health subcenter function, the 36.1% of respondents answered that 'enforcement of medical personnel and equipment' was required, and then 'improved medical technology'(25.5%), 'good attitude of physician'(14.9%), 'improved medical system'(13.3%), 'enforced drug'(6.7%) in next order. 12. The study on affecting factors to utilization of primary medical facilities was very difficult subject to systematize the analyzed results, due to a prejudice of protocol planner, surveyer and respondent, and variety and overlapping of subject matter.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.815-825
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• 2017

Visibility of lane marking is impaired at night or in the rain, which thereby threatens traffic safety. Recently, various studies and technologies have been developed to improve lane marking visibility, such as the extension of lane marking life expectancy (up to 1.5 times), improvement of lane marking equipment productivity, improvement of lane marking visibility by applying phosphorescent material mixed paint. Cost-benefit analysis was performed with considering various benefit items that can be expected. About 45% of traffic accidents would be prevented by improving lane marking visibility. Additionally, accident reduction benefit and traffic congestion reduction benefit were calculated as much as 246 billion KRW per year and 12 billion KRW per year, respectively, by reducing repaint cycle due to enhanced durability. 45 billion KRW per year is expected to reduced with improved lane detection performance of autonomous vehicle. Meanwhile, total increased cost when introducing phosphorescent material mixed paint to 91,195km of nationwide road is identified as 1922 billion KRW per year. However, economic feasibility could not be secured with 0.16 of cost-benefit ratio when applied to the road network as a whole. In case of "Accident Hot Spot" analyzing section window (400m), one or more fatality or two or more injured (one or more injured in case of less than 2 lanes per direction) per year were caused by pavement marking related accident, economic feasibility was secured. In detail, 3.91 of cost-benefit ratio is estimated with comparison of the installation cost for 5,697 of accident hot spot and accident reduction benefit. Some limitations and future research agenda have also been discussed.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.155-164
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• 2008

It is critical to develop a core ITS technology such as real-time travel time estimation in order that the efficient use of the ITS implementation can be achieved as the ITS infrastructure and relevant facilities are broadly installed in recent years. The provision of travel time information in real-time allows travellers to make informed decisions and hence not only the traveller's travel utilities but also the road utilization can be maximized. In this paper, a hybrid model is proposed to combine VDS and AVI which have different characteristics in terms of space and time dimensions. The proposed model can incorporate the immediacy of VDS data and the reality of AVI data into one single framework simultaneously. In addition, the solution algorithm is made to have no significant computational burden so that the model can be deployable in real world. A set of real field data is used to analyze the reliability and applicability of the proposed model. The analysis results suggest that the proposed model is very efficient computationally and improves the accuracy of the information provided, which demonstrates the real-time applicability of the proposed model. In particular, the data fusion methodology developed in this paper is expected to be used more widely when a new type of traffic data becomes available.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.149-159
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• 2012

The evaluation of public transit service quality is more complicated than evaluating other aspects of transportation service. Although various measures of effectiveness [MOEs] for transit service have been studied and applied, a more comprehensive and accurate MOE is still required. In the past, either data from user surveys or the experience of bus agency administrators and/or engineers used to measure the quality of service. However, recently, with reliable and accurate real time data from BMS(Bus Management System) and BIS(Bus Information System), more reliable and accurate MOEs are available. This study develops a service evaluation model from users' perspectives, which is based on user' cost models that consider passenger access time, riding time, waiting time, and discomfort due to in-vehicle overcrowding, violation of traffic laws, and accident rate. For validating proposed model, data from the BMS and transit-fare cards (T-Money Card) for Seoul's No. 472 main bus line were used. Models developed in this study provided reliable results.