• Journal of Digital Convergence
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• v.14 no.8
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• pp.253-259
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• 2016

Regarding the research on lane recognition, continuous studies have been in progress for vehicles to navigate autonomously and to prevent traffic accidents, and lane recognition and detection have remarkably developed as different algorithms have appeared recently. Those studies were based on vision system and the recognition rate was improved. However, in case of driving at night or in rain, the recognition rate has not met the level at which it is satisfactory. Improving the weakness of the vision system-based lane recognition and detection, applying sensor convergence technology for the response after accident happened, among studies on lane detection, the study on the curve road detection was conducted. It proceeded to study on the curve road detection among studies on the lane recognition. In terms of the road detection, not only a straight road but also a curve road should be detected and it can be used in investigation on traffic accidents. Setting the threshold value of curvature from 0.001 to 0.06 showing the degree of the curve, it presented that it is able to compute the curve road.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.19-25
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• 2005

This paper presents a lateral control system for the autonomous navigation vehicle that was developed and tested by Robotics Centre of Ecole des Mines do Paris in France. A robust lane detection algorithm was developed for detecting different types of lane marker in the images taken by a CCD camera mounted on the vehicle. $^{RT}Maps$ that is a software framework far developing vision and data fusion applications, especially in a car was used for implementing lane detection and lateral control. The lateral control has been tested on the urban road in Paris and the demonstration has been shown to the public during IEEE Intelligent Vehicle Symposium 2002. Over 100 people experienced the automatic lateral control. The demo vehicle could run at a speed of 130km1h in the straight road and 50km/h in high curvature road stably.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.6 no.2
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• pp.121-132
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• 2011

Objectives : The purpose of this study is to investigate the cervical spine curvature after whiplash injury by traffic accident. Methods : The cervical lateral radiographs of 102 outpatients who visited emergency room in Kyung-Hee university hospital at Gangdong after whiplash injury by road traffic accident were reviewed to measure the cervical spine angle using C1-7, C2-7 Cobb method, Sagittal tangent method, Jochumsen method and the Ishihara index by two oriental medical doctors. For statistics, we used SPSS version 17.0 for windows. Results : Means of cervical angle are $37.63{\pm}11.34^{\circ}$, $12.92{\pm}9.13^{\circ}$, $16.19{\pm}10.62^{\circ}$, $1.78{\pm}3.37$ and $8.51{\pm}9.78$ by C1-C7 Cobb Method, C2-C7 Cobb Method, Sagittal tangent method, Jochumsen method and Ishihara index, respectively. Hypolordosis is most numeral in patients by C1-C7 Cobb Method(n=40; 39.22%), Sagittal tangent method(n=68; 66.67%). And Straight is the most by Jochumsen method(n=54; 52.94%), but Normal is the most by Ishihara index(n=53; 51.96%). And Female has smaller curvature in cervical spine than male significantly by C2-C7 Cobb method and Sagittal tangent method(P<0.05). Conclusions : Whiplash injury tends to make hypolordosis or straight. And female has more vulnerable curvature than male in whiplash injury.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.2
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• pp.61-76
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• 2021

As the number of existing road tunnels increases every year, collapse and floor heaving accidents occur frequently during construction. The collapse among tunnel accidents dominates, so that studies related to the floor heaving are relatively insufficient. Accordingly, many studies to reinforce the lower part of the tunnel have been conducted, but the analysis on the effect of the curvature of the tunnel floor is insufficient. Therefore, in this study, the effects of the upper analysis area height and the coefficient of lateral earth pressure of the tunnel located on a tuff deterioration zone with a large rock cover, as well as the floor curvature, were examined through sensitivity analysis. As a result of the analysis, it turned out that the overall stability of the tunnel increases as the floor curvature increases, the coefficient of lateral earth pressure decreases, and the upper analysis region increases.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.2
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• pp.107-118
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• 2021

Due to the acceleration of road construction, the number and extension of tunnels are increasing every year. A lot of research has been done on the collapse of tunnels, but research on the invert heaving is insufficient. Therefore, in this study, a sensitivity analysis was performed using a geotechnical general-purpose program to analyze the effect of the invert curvature of a tunnel excavated on the soft ground. As a result, it was quantitatively confirmed that the stability of a tunnel was increased as the curvature of the tunnel invert was increased so that the safety factor was calculated to be large regardless of the ground conditions and the thickness of the support. In addition, it was confirmed that the stability of the tunnel was increased by reducing the convergence of the tunnel and the maximum bending stress supported by shotcrete. Therefore, when a tunnel is excavated on soft ground, it is believed that applying a curvature to the invert will increase the stability of the tunnel.

• Structural Monitoring and Maintenance
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• v.4 no.1
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• pp.1-15
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• 2017

Installation of sensors networks for continuous in-service monitoring of structures and their efficiency conditions is a current research trend of paramount interest. On-line monitoring systems could be strategically useful for road infrastructures, which are expected to perform efficiently and be self-diagnostic, also in emergency scenarios. This work researches damage detection in composite concrete-steel structures that are typical for highway overpasses and bridges. The techniques herein proposed assume that typical damage in the deck occurs in form of delamination and cracking, and that it affects the peak power spectral density of dynamic curvature. The investigation is performed by combining results of measurements collected by long-gauge fiber optic strain sensors installed on monitored structure and a statistic approach. A finite element model has been also prepared and validated for deepening peculiar aspects of the investigation and the availability of the method. The proposed method for real time applications is able to detect a documented unusual behavior (e.g., damage or deterioration) through long-gauge fiber optic strain sensors measurements and a probabilistic study of the dynamic curvature power spectral density.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.2
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• pp.10-16
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• 2000

The purpose of this study is to identify relationships between a central angle and a radius of curvature of divided roads in flat terrain of traditional villages, suggesting layout criteria for traditional villages: Nak-an, Sung-Eup, Ha-Whe. This study is sought to find the optimum model through the various SAS regression analyses. a regression analysis of this data was adopted to induce the relationship formula between a central angle of curve and a radius of curvature. Results of this study are as follows: 1) Most of the divided roads in traditional villages have a complex curve rather than a simple curve. 2) A central angle of curve has ranged from 11$^{\circ}$to 127$^{\circ}$, with a mean degree of 63.9. 3) In the lower level of central angle(11-40$^{\circ}$), the branch roads have distributed with a high frequency, but with a low frequency in the higher level of central angle(90-140$^{\circ}$). 4) A radius of curvature in the divided roads has ranged from 0.9m to 59.6, but half of the roads have concentrated on 1-6m of the curvature. 5) Compared to the result of hilly villages in previous study(Ahn, 1999), value of central angels in flat villages is lower than that of hilly villages, while a mean value of the curvature is higher than that of hilly villages. 6) A Non-linear regression analysis, resulting from the SAS application, was useful method to induce a relationship formula between a central angle and a radius of curvature in the branch roads. Our study's formula is as follow: R=100.3*EXP(-0.06*$\delta$)+3.91. 7) Our study model has less error than that of the Kishizuka's method, being applicable to a broader range of the branch roads. 8) A minimum radius of curvature in our study has showed 3.9m, suggesting to reconsider applications of the Kishizuka's(5.8m) in the footpass design, In the study for this presupposition model the efficiency and utility of it can be estimated to grow large according to how much and how far it includes both extremes of data. This study is for the application to a design in future through the numerical formula of divided roads of various traditional villages. The studies from now on will be about the quasi-hilly quasi-hilly village and hilly village supplementing these factors more.

• Geomechanics and Engineering
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• v.35 no.4
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• pp.411-424
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• 2023

Reasonable estimates of tunnel lining dislocations in the operation stage, especially under longitudinal differential settlement, are important for the design of waterproof gaskets. In this paper, a modified shell-joint model is proposed to calculate shield tunnel dislocations under longitudinal differential settlement, with the ability to consider the nonlinear shear stiffness of the joint. In the case of shell elements in the model, an elastoplastic damage constitutive model was adopted to describe the nonlinear stress-strain relationship of concrete. After verifying its applicability and correctness against a full-scale tunnel test and a joint shear test, the proposed model was used to analyze the dislocation behaviors of a shield tunnel in Shanghai Metro Line 2 under longitudinal differential settlement. Based on the results, when the tunnel structure is solely subjected to water-earth load, circumferential and longitudinal joint dislocations are all less than 0.1 mm. When the tunnel suffers longitudinal differential settlement and the curvature radius of the differential settlement is less than 300 m, although maximum longitudinal joint dislocation is still less than 0.1 mm, the maximum circumferential joint dislocation is approximately 10.3 mm, which leads to leakage and damage of the tunnel structure. However, with concavo-convex tenons applied to circumferential joints, the maximum dislocation value reduces to 4.5 mm.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.59-68
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• 2017

PURPOSES : The objective of this study is to evaluate the potential risk level of road cave-ins due to subsurface cavities based on the deflection basin measured with falling weight deflectometer (FWD) tests. METHODS: Ground penetrating radar (GPR) tests were conducted to detect road cavities. Then FWD tests were conducted on 13 pavement test sections with and without a cavity. FWD deflections and a deflection ratio was used to evaluate the effect of geometry of the cavity and pavement for road cave-in potentials. RESULTS : FWD deflection of cavity sections measured at 60 cm or a closer offset distance to a loading center were 50% greater than more robust sections. The average deflection ratio of the cavity sections to robust sections were 1.78 for high risk level cavities, 1.51 for medium risk level cavities, and 1.16 for low risk level cavities. The relative remaining service life of pavement with a cavity evaluated with an surface curvature index (SCI) was 8.1% for the high level, 21.8% for the medium level, and 89.8% compared to pavement without a cavity. CONCLUSIONS : FWD tests can be applied to detect a subsurface cavity by comparing FWD deflections with and without a cavity measured at 60 cm or a closer offset distance to loading center. In addition, the relative remaining service life of cavity sections based on the SCI can used to evaluate road cave-in potentials.

• International Journal of Highway Engineering
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• v.17 no.5
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• pp.47-56
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• 2015

PURPOSES: The purpose of this study is to estimate the impact of variable message signage (VMS) on traffic safety as a function of road curve radius using statistical methods. METHODS: In order to analyze the impact of VMS installations on traffic safety, travel speed, lateral distance, and geometric data relating to road curvature in each study area was acquired and analyzed for the impact of providing VMS information on driver performance and traffic safety using statistical methods including student t-test, Mann-Whitney test, and the Anderson-Darling test for estimating traffic safety hazard zone in each lane. RESULTS: As a result of analyzing driver performance characteristics before and after providing VMS information, it was determined that by providing VMS information, mean travel speed is deceased and vehicles are driven with increased precision, following the centerline in the first and second lanes. Also the results of analyzing traffic safety impacts of VMS indicate that traffic safety performance factors in the first lane of the Gapyeong section can, on average, increase in the left and right side of the lane by 19.22% and 68.98%, respectively, and in the case of the second lane, safety impacts, on average, can increase in both sides by 100%. For the Hongcheon section, traffic safety impacts in the first lane, on average, can increase along the left and right sides of the lane by 32.31% and 47.18%, and within the second lane, traffic safety can be increased along the left and right side of the lane by 10.97% and -0.01%, respectively. CONCLUSIONS: Based on the results of this study, the impact on traffic safety obtained by providing VMS information for road sections with smaller curve radii is greater than can be obtained for road sections with larger curve radii.