• International Journal of Highway Engineering
• /
• 제10권4호
• /
• pp.117-125
• /
• 2008

Recently, users of bicycles as a green mode are rising sharply, but there are few efforts to increase bicycle safety and to decrease the number of accidents between vehicles and bicycle users. Therefore, this research seeks to improve bicycle safety at intersections by analysing causation factors of bicycle accidents pattern and providing optimal intersection design guidelines. For this study, real bicycle accident data of fifty six occurred in the Incheon metropolitan area in the year of 2005 were collected and field surveys were conducted. In addition, this research developed a bicycle accident pattern model with using multinomial logit model. The model results showed that presence of fatality, presence of traffic islands on the minor road, highway_type, weather, presence of traffic bus_stop on the major road, minor road lane width, victim induce factor are significant for bicycle safety.

• International Journal of Highway Engineering
• /
• 제19권2호
• /
• pp.153-165
• /
• 2017

PURPOSES : With the increasing number of older drivers in an aging society, there is a growing need for research and planning on traffic safety for the older drivers using an improved road geometry design. This study also proposed a modified urban road interchange design, which aims to keep the older drivers away from accident-prone and high-traffic areas of the city. METHODS : In this study, we examined accident data records of older drivers to identify accident-prone zones and intersections; we studied the road geometry at these zones and analyzed if it was an underlying cause for higher number of accidents. Based on the research and subsequent analysis, we suggested plans for improvement of road geometry design at these intersections. RESULTS :By studying historic data and analyzing factors that affect the likelihood of accidents of vehicles driven by older drivers and after studying suitable traffic accident prediction models, we identified the major variables that need to be modified at accident-prone intersections, such as the width of a left turn lane at an intersection and the radius of the right turn lane at a street corner. The results have a significance probability of less than 0.001 and a 95% confidence level. To improve safety at the identified intersection, this study suggests the installation of a left-turn-lane-shaped Positive Offset and a right-turn-lane-shaped Slip Lane concept and an adjustment of intervals between intersections.

• Journal of the Ergonomics Society of Korea
• /
• 제35권3호
• /
• pp.135-142
• /
• 2016

Objective: Objective of this study is to provide characteristics of injury frequency and severity by driving condition in large truck-related traffic collisions. Background: Traffic accidents involving large trucks draw a lot of attention in accident prevention and management policies since they bring about severe human and financial damages. Method: In order to identify the major risk factors of accidents by driving condition, 255 recognized traffic accidents by large truck drivers were analyzed in terms of time of the day, road type, and shape of the road. Results: The driving conditions in the results are represented by the following form of combination, "Road Type (Non-expressway or Express) - Shape of Roads (Straight, Curved, Downhill, or Intersection) - Time of Accidents (Day or Night)". In the analysis of injury frequency, Non-expressway-Straight-Day condition was the most frequent one. Meanwhile, Expressway-Curved-Day, Non-expressway-Curved-Night and Non-expressway-Intersection-Night were evaluated as high level in view of injury severity. Also, Expressway-Straight-Night is the driving condition that is the highest in risk among the conditions that have to be managed as grade "High". Non-expressway-Straight-Night, Non-expressway-Downhill-Day, and Non-expressway-Curved-Day are also categorized as grade "High". Conclusion and Application: Safety managers in the fields require basic information on accident prevention that can be easily understood. The research findings will serve as a practical guideline for establishing preventive measures for traffic accidents.

• Journal of Korean Society of Transportation
• /
• 제31권1호
• /
• pp.77-86
• /
• 2013

This paper focuses on the development of analytical models for estimating the changes in saturation flow rates (SFR) at the stop-lines of a signalized intersection due to the existence of nearby work-zones, and thereby calculating the prevailing capacity values for specific lane groups. Major changes were incorporated in the logics of previous models and significant revisions have been made to secure the accuracy and simplicity. Furthermore, much attention was paid to model validation by making comparisons to both extensive simulation results and empirical data from various sites. It was found that SFRs are highly sensitive to the location of work-zones, the distance to each work-zone from the stop-line of a concerned approach, the number of lanes open and closed, and the effective green time. Using such geometric and operating conditions that constitute work-zone environment, the proposed models successfully estimated SFR values with a miniscule margin of error.

• Journal of the Korean Society of Industry Convergence
• /
• 제4권1호
• /
• pp.41-49
• /
• 2001

This study developed signal optimization algorithm by analyzing vehicle arrival patterns. The major principle of signal optimization is dissipate all queueing vehicle in 1cycle and assign delay time uniformly for all approaches. For this, this study used optimal green time and surplus green time. Optimal green time calculated by estimated traffic volume from vehicle arrival model. Surplus green time defined as the gap of optimal green time and queue dissipated time. And alternative cycle has minimum surplus green time was selected as the optimal cycle. Finally, total delay and average delay per vehicle can be calculated by using queueing theory.

• Bulletin of the Korean Mathematical Society
• /
• 제54권2호
• /
• pp.507-519
• /
• 2017

We present an upper bound on the Cheeger constant of a distance-regular graph. Recently, the authors found an upper bound on the Cheeger constant of distance-regular graph under a certain restriction in their previous work. Our new bound in the current paper is much better than the previous bound, and it is a general bound with no restriction. We point out that our bound is explicitly computable by using the valencies and the intersection matrix of a distance-regular graph. As a major tool, we use the discrete Green's function, which is defined as the inverse of ${\beta}$-Laplacian for some positive real number ${\beta}$. We present some examples of distance-regular graphs, where we compute our upper bound on their Cheeger constants.

• Journal of Information Technology Applications and Management
• /
• 제23권3호
• /
• pp.87-97
• /
• 2016

This paper proposes a fast sound source localization method using a TDOA sign-based algorithm. We present an L-shaped microphone set-up which creates four major regions in the range of $0^{\circ}{\sim}360^{\circ}$ by the intersection of the positive and negative regions of the individual microphone pairs. Then, we make an initial source region prediction based on the signs of two TDOA estimates before computing the azimuth value. Also, we apply a threshold and angle comparison to tackle the existing front-back confusion problem. Our experimental results show that the proposed method is comparable in accuracy to previous three microphone array methods; however, it takes a shorter computation time because we compute only two TDOA values.

• Journal of Korean Elementary Science Education
• /
• 제17권1호
• /
• pp.47-60
• /
• 1998

The purpose of this study was to analyze the problem solving strategies of elementary school students and to find out correlations between the functional mental capacity, the perseveration error and the Creature Card Task solving ability. To study this purpose, four categories were selected through pilot test. The sample consisted of 231, the 4th grade students and the 5th grade students in Inchon, Korea and selected 32 students among them. Three instruments were used in this study, Creature Card Task, FIT(Figural Intersection Test) and WCST(Wisconsin Card Sorting Test). Researcher interviewed 32 students about Creature Card Task solving strategies and tests with FIT, WCST. Major findings of the study are as follows: 1. Creature Card Task solving strategies of the selected 4th & 5th grade students were different. Some students solved problems during individual interviews. 2. Creature Card Task solving abilities were significantly correlated with the functional mental capacity and the perseveration error.

• Journal of Institute of Control, Robotics and Systems
• /
• 제12권7호
• /
• pp.650-657
• /
• 2006

The LPMS (Loose Part Monitoring Systems) are used widely for detecting the impact position in the nuclear reactor. There are some major methods to detect impact position in LPMS such as the triangular method, the rectangular method, the circular intersection method and so on. The time difference of these methods are calculated using S0-mode and A0-mode waves of each sensor. In this paper, we propose a method to detect impact position using the enveloped waves of acquired signals. The result of this paper show that the position detecting accuracy and reducing the processing time are proposed method is improved than traditional methods.

• Journal of Institute of Control, Robotics and Systems
• /
• 제12권10호
• /
• pp.962-967
• /
• 2006

Indoor positioning is highlighted recently, and various kinds of indoor positioning systems are under developments. Since positioning systems have their own characteristics, proper positioning scheme should be chosen according to the required specifications. Positioning methods are classified into time-based and angle-based one. This paper presents the error analysis of time-based and angle-based location methods. Because measurements of these methods are nonlinear, linearizations are needed in both cases to estimate the user position. In the linearization, Gauss-Newton method is used in both cases. To analyze the position error, we investigate the error ellipse parameters that include eccentricity, rotation angle, and the size of ellipse. Simulation results show that the major axes of TOA and AOA method lie in different quadrants at most region of workspace, especially where the geometry is poor. When the TOA/AOA hybrid is employed, it is found that the error ellipse is reduced to the intersection of ellipses of TOA and AOA.