• International Journal of Highway Engineering
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• v.10 no.4
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• pp.213-224
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• 2008

Flexible pavement responses to vehicular loading, such as critical stresses and strains, in each pavement layer, could be predicted by the multilayered elastic analysis. However, multilayered elastic theory suffers from major drawbacks including spatial dimension of a numerical model, material properties considered in the analysis, boundary conditions, and ill-presentation of tire-pavement contact shape and stresses. To overcome these shortcomings, three-dimensional finite element (3D FE) models are developed and numerical analyses are conducted to calculate pavement responses to moving load in this study. This paper introduces a methodology for an effective 3D FE to simulate flexible pavement structure. It also discusses the mesh development and boundary condition analysis. Sensitivity analyses of flexible pavement response to loading are conducted. The infinite boundary conditions and time-dependent history of calculated pavement responses are considered in the analysis. This study found that the outcome of 3D FE implicit dynamic analysis of flexible pavement that utilizes appropriate boundary conditions, continuous moving load, viscoelastic hot-mix asphalt model is comparable to field measurements.

• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.73-82
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• 2005

Linear traverse method and point count method described at ASTM have been widely used to estimate the air void system in hardened concrete. These methods, however, are rarely used at present, because they require many efforts and time consuming works. Also these results depend on each person's decision, and are not repeatable. Thus, new image analysis method using microscope and computer processes has been approached for analyzing air void system in hardened concrete. The purpose of this study was to analysis the air void systems in latex-modified concretes using a reasonable and objective image analysis method with main experimental variables such as cement types(ordinary portland cement, rapid setting cement) and latex contents(0%,15%). In the results of this study, the use of polymer latex showed that it could be attributed to its air void systems, due to the fact that the latex emulsion acts as an air-entraining agent, which thus generally guarantees an adequate air-void system.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.69-77
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• 2008

This article proposes new method for estimating pedestrian quality of service(QOS) that is useful to changing pedestrian environment by examining pedestrian quality of service as well as developing new method that integrate qualitative variables into the estimating indicators for the pedestrian movement right. Based on survey questionnaire addressed to experts group, the obtained data for the indicators were analyzed through Analytic Hierarchy Process(AHP). The results show that pedestrian traffic flow(quantitative figure: 52%), sidewalk geometric(quantitative figure: 16%), sidewalk usage behavior(qualitative figure: 11%) in commercial and business zone pointed out the importance of quantitative indicators such as pedestrian traffic flow, and sidewalk geometric. In addition, the results also show that pedestrian traffic flow(quantitative figure: 30%), sidewalk geometric(quantitative figure : 22%), sidewalk usage behavior(qualitative figure: 20%) indicate the significance of qualitative indicators such as pedestrian's sidewalk usage.

• International Journal of Highway Engineering
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• v.2 no.2
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• pp.149-161
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• 2000

The stiffness of the subbase materials is represented by the resilient modulus, $M_R$, which are very important properties in the mechanistic design of flexible pavement system. However, the cyclic $M_R$ testing method is too complex, expensive, and time consuming to be applicable on a production basis. In this study, the alternative $M_R$ testing technique for subbase materials was developed using a free-free resonant column (FF-RC) test considering deformational characteristics of subbase materials. To estimate the deformational characteristics of subbase materials, effects of strain amplitude and mean effective stress on modulus of subbase materials were investigated. The $M_R$ values determined by alternative testing procedures matched well with those determined by standard $M_R$ test, showing the capability of the proposed methods being used in determining $M_R$ values.

• Journal of Korea Port Economic Association
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• v.25 no.2
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• pp.95-114
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• 2009

The aim of this paper is to evaluate weight and priority values for 'inner consisted factors' and 'outer requested factors' of logistics system using the AHP(Analytic Hierarchicy Process) method. As for analysis regarding inner consisted factors, the results were shown as follows: a road transportation (0.312) as first rank; a marine transportation (0.269) as second rank; a railway transportation (0.239) as third rank; an air transportation (0.118) as fourth rank, and a pipeline transportation (0.063) as fifth rank. In terms of analysis regarding outer requested factors, the results were came out as follows: an infrastructure (0.322) as first rank; a performance (0.206) as second rank; an information system (0.151) as third rank; a human resources (0.121) as fourth rank, a business environment (0.075) as fifth rank; a connectivity (0.073) as sixth rank, and a political environment (0.052) as seventh rank.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.635-644
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• 2005

This paper is. a study on relation between road traffic noise(RTN) and sound power level(PWL). At present, many experimental formulae and prediction formulae are used for prediction of RTN. But these formulae are difficult to appiy to the metropolitan area because these formulae are inaccurate in the different condition from reference condition. This paper calculate RTN and PWL of each prediction formula, choose the best one and make a noise map of the subject area. Procedure is as follows. First, calculate $L_{eq}$ of RTN using experimental formulae and prediction formulae. Second, calculate PWL using $L_{eq}$ of RTN and distance attenuation for point source at semi-free field. Third, choose the most accurate formula. And finally, make a noise map of the subject area at present and future. The result using noise map will be able to apply to application field. Noise mapping tool used on this paper is Raynoise program using Ray Tracing Method(RTM), Mirror Image Source Method(MISM) and Hybrid Method(HM).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.513-520
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• 2017

For the last 60years, North Korea has constructed a lot of roadway bridges with different standard from that used in South Korea, and since North Korea prefer to take advantage of train more than truck for long distance transport, the construction and maintenance of roadway bridges have not been constructed effectively. Upon these situations, an exact evaluation of the resisting capacity for bridges in North Korea has been required to check of any bridge can be used in time of war. This paper introduces an evaluation of bridges in North Korea on the basis of Military Load Classification (MLC). Three different types of concrete bridges are considered, and the numerical analysis and design calculation give the military loadings which can pass through the bridges in North Korea.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.687-690
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• 2007

This study is a basic research on looking onto bringing performance warranty contract into the country, to consider the usage in architecture which it is usually used on road pavement in developed countries. The study will also apply performance warranty contracts on public private partnerships through examination and analysis of various matters which will lead to globalization of the korean architecture industry, the increase of quality of result, better convenience for the orderer, the decrease of cost, and the acceleration on research for technical development.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.239-240
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• 2019

본 논문에서는 유아보호를 위한 차량용 스마트 알림 시스템을 설치해야 한다는 것을 제안한다. 여름철 유아들이 차량에 갇혀 숨지는 안타까운 사건이 빈번히 일어났다. 현행 도로교통법에서는 어린이 통학버스를 운전하는 사람은 운행을 마친 후 어린이나 영유아가 모두 하차했는지를 확인 하도록 규정하고 있고 통학차량에 일정 인원 이상의 유아들이 탑승하면 통솔인원교사가 등.하교 길에 동행하도록 의무화 되어 있다. 그럼에도 불구하고 여전히 통학차량에 유아들이 방치되어 사망하는 사건사고가 일어나고 있다. 외국에는 챠량 내부의 모든 버튼을 인식 하여야 차량의 시동이 멈추게 된다. 하지만 유아를 차량에 두고 나오는 사고가 났다. 차량용 스마트 알림 시스템은 기존 버스 내부에 RF카드를 인식하면 유아의 학부모에게 문자가 전송되게 되며 차량 어디에 위치하였는지 표시가 되게 된다. 이로인해 차량에 유아를 두고 내리는 일이 없게 되며 유아가 차량을 언제 탑승하였는지 확인할 수 있게 된다.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.97-104
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• 2008

Many atypical structures on the roadside are exposed to traffics unshielded posing great danger. One way to shield an atypical structure to secure the occupant safety is to stack energy absorbing material modules in front of the structure. This paper presents the analysis method of module type crash cushion made of EPS blocks using simple energy balance of the car and crash cushion and numerical examples for 0.9ton-500km/h, 0.9ton-60km/h and 0.9ton-70km/h impact are presented. This method gives simple estimation of maximum acceleration, time of crash, whether or not the vehicle stops completely before whole cushion is being crushed. However, since the acceleration and velocity data from the analysis is so crudely spaced that calculation of safety indices such is RA and OIV is not possible. Problem is overcome by using data interpolation. The spline and linear interpolation is introduce and safety analysis is made and the results are compared.