• 한국자동차공학회논문집
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• 제13권4호
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• pp.97-104
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• 2005

Vision-based lane sensing systems require accurate and robust sensing performance in lane detection. Besides, there exists trade-off between the computational burden and processor cost, which should be considered for implementing the systems in passenger cars. In this paper, a stereo vision-based lane detection system is developed with considering sensor configuration aspects. An inverse perspective mapping method is formulated based on the relative correspondence between the left and right cameras so that the 3-dimensional road geometry can be reconstructed in a robust manner. A new monitoring model for estimating the road geometry parameters is constructed to reduce the number of the measured signals. The selection of the sensor configuration and specifications is investigated by utilizing the characteristics of standard highways. Based on the sensor configurations, it is shown that appropriate sensing region on the camera image coordinate can be determined. The proposed system is implemented on a passenger car and verified experimentally.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.916-919
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• 2004

The monopole theory has long been used to model air-pumped effect from the elastic cavities in car tire. This approach models the change of an air as a piston moving backward and forward on a spring and equates local air movements exactly with the volume changes of the system. Thus, the monopole theory has a restricted domain of applicability due to the usual assumption of a small amplitude acoustic wave equation and acoustic monopole theory. This paper describes an approach to predict the air-pumping noise of a car ave with CFD/Kirchhoff integral method. The type groove is simply modeled as piston-cavity-sliding door geometry and with the aid of CFD technique flow properties in the groove of rolling car tyre are acquired. And these unsteady flow data are used as a air-pumping source in the next Cm calculation of full tyre-road geometry. Acoustic far field is predicted from Kirchhoff integral method by using unsteady flow data in space and time, which is provided by the CFD calculation of full tyre-road domain. This approach can cover the non-linearity of acoustic monopole theory with the aid of using Non-linear governing equation in CFD calculation. The method proposed in this paper is applied to the prediction of air-pumping noise of modeled car tyre and the predicted results are qualitatively compared with the experimental data.

• 한국도로학회논문집
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• 제16권5호
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• pp.173-182
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• 2014

PURPOSES : The purpose of the study is to a) explore the operating speed of trucks on rural highways affected by road geometry, and thereby b) develop a predictive model for the operating speed of trucks on rural highways. METHODS : Considering that most of the existing studies have focused on cars, the current study aimed to predict the operating speed of trucks by conducting linear regression analysis on the speed data of trucks operating on the linear-curved-linear portions of the road as a single set. RESULTS : The operating speed in the plane curve portion increased with the length of the curve, and decreased with a lower vertical grade and a smaller curve radius. In the straight plane portion, the operating speed increased with a larger curve radius(upstream), and decreased with an increase in the change of the vertical grade, depending on the length of the vertical curve. CONCLUSIONS : This study developed estimation models of truck for operational speed and evaluated the degree of safety for horizontal and vertical alignments simultaneous. In order to represent whole area of the rural highway, the models should be ew-analyzed with vast data related with road alignment factor in the near future.

• 한국도로학회논문집
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• 제19권5호
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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.

• 콘크리트학회지
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• 제10권2호
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• pp.127-135
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• 1998

프리캐스트 세그멘탈 교량의 3차원적인 선형관리를 수행할 수 있는 S/W로서 GEOCON이 개발되었다. GEOCON은 기본적으로 제작장에서 세그멘트 제작관리를 통한 선형관리를 실시하고, 그 결과로서 자동적으로 계산되는 제작선형은 가설시 선형관리에 활용된다. 본 논문에서는 실제 현장에서 나타날 수 있는 검측오차등으로 인하여 수치계산상으로는 마치 정확한 선형관리가 이루어지는 것으로 나타날 수 있는 상황들을 방지하기 위해 GEOCON에서 채택하고 있는 기술적인 특징들에 대하여 논하고 있다. 또한 실제 현장적용을 통하여 GEOCON의 효용성을 검증하였다. GEOCON을 통하여 선형관리된 부산항 배후도로 현장은 총 길이 2109m의 프리캐스트 세그멘탈 교량구간을 포함하고 있으며 고임판의 사용없이 허용 관리치 내에서 매우 정확한 선형관리가 이루어졌다.

• 한국도로학회논문집
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• 제9권1호
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• pp.39-46
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• 2007

동일한 물성을 가지는 포장이라도 포장의 구조적인 형상에 따라 역해석 결과가 다르게 나타난다. 본 논문에서는, 구조적인 형상을 고정하고 동적 하중을 모사하는 3차원 유한요소모델을 만들어 얻어진 최대 처짐과 AREA의 분포를 통해서 물성을 추정하는 수정된 AREA 도표를 제안하였다. 제안된 도표를 이용하여 단일 무한 슬래브에 대한 민감도 분석 결과 노상의 깊이가 질어지면 처짐과 AREA가 증가하는 것으로 나타났고 4.0m이상에서는 큰 차이를 나타내지 않았다. 층별 물성과 노상 깊이가 같은 경우 단일 무한 슬래브 모델과 다중 유한 슬래브 모델을 비교하는 경우 다중 유한 슬래브 모델의 처짐과 AREA가 더 크게 나타났다.

• 한국도로학회논문집
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• 제18권3호
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• pp.21-32
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• 2016

PURPOSES : In this paper, the analytical solutions suggested to simulate the behavior of rheological fluids were rigorously re-derived and investigated for fixed conditions to evaluate the applicability for the solutions on a mini-cone slump test of cement paste. The selected solutions with proper boundary conditions can be used as reference solutions to evaluate the performance of numerical simulation approaches, such as the discrete element method. METHODS : The slump, height, and spread radius for the given boundary and yield stress conditions that are determined by five different analytical solutions are compared. RESULTS : The analytical solution based on fluid mechanics for pure shear flow shows similar results to that for intermediate flow at low yield stresses. The fluid mechanics-based analytical solution resulted in a very similar trend to the geometry-based analytical solution. However, it showed a higher slump at high yield stress and lower slump at low yield stress ranges than the geometry-based analytical model. The analytical solution based on the mini-cone geometry was not significantly affected by the yield criteria, such as von Mises and Tresca. CONCLUSIONS : Even though differences among the analytical solutions in terms of slump and spread radius existed, the difference can be considered insignificant when the solutions were used as reference to evaluate the appropriateness of numerical approaches, such as the discrete element method.

• 한국도로학회논문집
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• 제7권4호
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• pp.163-171
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• 2005

현재의 도로설계기준은 안전주행을 위한 최소한의 요건만을 제시하고 있기 때문에 이 설계기준에 따라 건설된 도로는 운전자가 주행 중 기대하는 구조 및 환경을 충분히 반영하였다고 보기 어렵다. 따라서 한국건설기술연구원에서는 포로의 안전성을 평가하고 주행안전성을 제고하기 위해 도로안전성 조사분석차량을 개발하고 있다. 본 논문에서는 이 차량에 탑재된 다양한 자료수집 장비 중 일정거리간격으로 디지털 영상을 취득하는 영상취득시스템에 중점을 두고 기술하였다. 영상취득시스템은 도로 및 주변시설물을 운전자의 시점에서 촬영하는 전방카메라와 차선추출을 위해 차량의 좌우에서 도로면을 촬영하는 측하방카메라, 일정거리간격으로 영상촬영 신호를 발생하는 동기화장치로 이루어져 있다. 각 영상은 위치정보와 함께 저장되므로 전방영상은 길어깨 폭 측정 등의 기하구조 계산에 사용되고. 측하방영상은 도로의 선형을 대표하는 중앙차선을 추출하는데 유용하게 사용될 수 있을 것으로 판단된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.303-310
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• 2008

In Korea, the current noise impact assessment has not yet considered the vertical noise propagation property by buildings and other obstacles. And noise control plan has been established without conducting the economic assessment for the noise control facilities. A noise map is used to calculate the noise level based on a theoretical formula or an empirical formula, and also predict the characteristics of vertical propagation by linking with a geometry data. And It is Possible to analyze cost-effect of noise control facilities by consider installation costs. In this study, we addressed the application of noise map for noise impact assessment and cost-effect analysis of noise control facilities.

• 한국도로학회논문집
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• 제19권4호
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• pp.53-59
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• 2017

PURPOSES : This study deals with traffic accidents involving trucks. The objective of this study is to develop a traffic accident model for trucks at roundabouts. METHODS : To achieve its objective, this study gives particular attention to develop appropriate models using Poisson and negative binomial regression models. Traffic accident data from 2007 to 2014 were collected from TAAS data set of road traffic authority. Thirteen explanatory variables such as geometry and traffic volume were used. RESULTS : The main results can be summarized as follows: (1) two statistically significant Poisson models (${\rho}^2=0.398$ and 0.435) were developed, and (2) the analysis revealed the common variables to be traffic volume, number of exit lanes, speed breakers, and truck apron width. CONCLUSIONS : Our modeling reveals that increasing the number of speed breakers and speed limit signs, and widening the truck apron width are important for reducing the number of truck accidents at roundabouts.