• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.449-456
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• 2007

This research was conducted to analyze the features of the critical tensile stresses at the top and bottom of the concrete slab in the jointed concrete pavement (JCP) when subjected to both the environmental and vehicle loads. First, the stress distribution in JCP was analyzed when the system was subjected to only the environmental loads or the vehicle loads by using the finite element model of JCP. Then, the stresses were analyzed when the system was subjected to the environmental and vehicle loads at the same time. From this study, it was found that the critical tensile stresses at the slab bottom under the vehicle loads were almost constant regardless of the loading positions once the loads were applied at the positions having some distance from the transverse joint. The critical tensile stresses at the slab bottom could be obtained using the model consisting of normal springs for underlying layers by adding the critical stresses due to the environmental loads and the vehicle loads for the curled-down slab, and by subtracting the critical stress due to the environmental loads from that due to the vehicle loads for the curled-up slab. The critical tensile stresses at the top of the slab could be obtained using the model consisting of tensionless springs for underlying layers by adding the critical stress due to the environmental loads and the stress at the middle of the slab under the vehicle loads applied at the joint for the curled-up slab. An alternative to obtain the critical stresses at the top of the slab for the curled-up slab was to use the critical stresses under only the environmental loads obtained from the model having normal springs for underlying layers.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.240-247
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• 2013

Purpose: This study was conducted to develop a rubber-crawler type vehicle as a traveling device for harvesting water-dropwort cultivated in water contained paddy rice field in winter season. Methods: A commercial rubber-crawler type vehicle was used to investigate application of rubber crawler to the paddy rice field as preliminary test. As the result of the preliminary test, a both prototype traveling device with rubber crawlers for a water-dropwort harvest was designed with inclination of $45^{\circ}$ at the front-end and rear-end of crawler under the basic water depth of 0.6 m in the paddy rice field. The device was fabricated and attached to the experimental harvesting test devices on the front of the prototype vehicle. The size of the prototype crawler vehicle with a harvesting part is $2,800{\times}1,460{\times}1,040 $ (mm) ($L{\times}W{\times}H$) with weight of 9.21 kN (maximum). Sizes of the crawler of prototype vehicle are ground contact length of 900 mm, width of 180 mm, height of 1,070 mm and distance between center to center of crawlers of 720 mm. The side-overturn angle of the prototype was $26.4^{\circ}$. Results: Driving performance of the prototype vehicle in water contained paddy field were good at both forward and reverse (backward) directions as weights were applied. The drawbar pull and the maximum sinking depth of the prototype vehicle were 3.5 kN and 0.13 m respectively at water depth of 0.5 m, when the weight and bearing capacity of the prototype rubber crawler in the paddy field were 8.51 kN and 26.3 $kN/m^2$, respectively. Conclusions: Results of the driving test performance of the prototype crawler in paddy rice field at the water depth of 0.5 m were satisfactory. The prototype had enough drawbar pull and driving ability in the deep water contained paddy field.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.434-439
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• 1993

This paper present a sensor based obstacle avoidance method which is based on a VFH(Vector Field Histogram) method. The basic idea of obstacle avoidance is to find a minimum obstacle direction and distance. From the minimum sonar index and the target direction high level system determine steering angle of mobile robot. The sonar sensor system consists of 12 ultra sonic sensor, and each sensor have its direction and safety value. This method has advantage on calculation speed and small memory. This method is implemented on indoor autonomous vehicle'ALiVE-2'.

• Journal of the Korean Professional Engineers Association
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• v.34 no.3
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• pp.28-32
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• 2001

Using the CNG(compressed natural gas) and LPG(liquified petroleum gas) as the automotive fuel will be expanded because of their clean effect to the environmental air qualify. But these programs of gas using expansion would have a difficulty due to public consideration of gas utilities as a big hazard. The Ministry of Environment has an ambitious plan to substitute more than 25,000 buses with CNG and ensure more than 200 CNG refueling stations as well by the year of 2007. However, it is very difficult to establish new CNG and LPG refueling stations because of expanded safety distance than ever before by several major explosion accidents.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.350-353
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• 2009

본 논문에서는 국토모니터링 기술의 한 부분으로서 도로 지역에 대한 효율적인 실시간 교통모니터링을 위해 도로상의 차량 정보를 LiDAR 데이터로부터 취득하는 과정을 실험하였다. 도로영역의 데이터를 추출하기 위해서 좌표 변환된 수치지도와 LiDAR 데이터를 이용하였고, 국지적 임계치 필터링을 사용하여 추출된 도로영역의 데이터를 차량과 도로의 자료로 분리시키는 작업을 수행하였으며, 추출된 차량의 포인트들을 이용하여 차량을 표현할 수 있는 기본 속성값을 추출하였다. 마지막으로, 분리된 차량의 포인트에 대해서 MDC(Minimum Distance Classification) 클러스터링를 이용하여 차량의 종류를 분류하였다. 결과적으로 본 연구를 통하여 차량인식과 차량의 종류에 대한 분류를 수행할 수 있음을 확인하였다.

• Journal of Korean Society of Transportation
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• v.19 no.5
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• pp.85-97
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• 2001

In this study, the purpose behind this research is to propose index to be used for classification of functional the urban streets and to select the feasible length of special management link by the index. This special management link help decision makers found a transportation policy. In order to perform functional classification, index such as average traveled distance, link VKT and VKT per length-lane are use at the study. Average traveled distance index is average traveled distance divided by length of Path k and VKT per length-lane is trip volume characteristic considering lanes and length of Path k. Special management links on which major part of the vehicle are selected with using Path-VKT which represents how many long-distance touring vehicles are on the arterial road. The selection of special management links are performed with network composed of 14 paths (arterial roads) in seoul The total distance of special management links resulted from the above analysis is 141km(35.0% of the whole paths length) and total VKT of the special management links is 4,152,475 VKT(45.2% of the whole paths VKT)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.703-715
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• 2017

In this paper, we analyze the channel characteristics of the long distance air-ground wideband common data link and we propose a mathematical method to analyze the effect of narrowband and wideband interference of air-ground channel on the received signal of wideband data link. In this paper, we analyze the reception performance according to the communication distance using the proposed performance analysis method, and found out that the communication distance is limited by the narrowband and wideband interference of ground reflection wave. As a result of the performance analysis of the method of controlling the receiving antenna upward, not only the narrow band but also the wideband interference is effectively reduced, so that the communication distance is increased even in the existing wideband data link not including the equalizer.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.3
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• pp.28-38
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• 2017

The study is to analyze the aggressive driving behavior in the protected/permissive left turn(PPLT) intersections in Gunsan City. As a result of the logistic regression model, increasing of driver's age and driving experience, non-peak time, no company, sedan and male have a tendency to behave aggressive driving to the opposite vehicles. When the vehicles try to turn the unprotected left in the PPLT intersection, the opposite vehicle drivers recognize them at the aggressive driving behavior if the distance to opposite vehicles is not enough. The relationship between driver characteristics and the distance to the opposite vehicles is analyzed under aggressive driving behavior. increasing of age and company, peak time tend to influence the short distance opposite vehicles while male and higher driving experience the middle and long distance. Sedan has the aggressive possibility to shorter distance opposite vehicles rather than others.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.247-254
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• 2018

Purpose: Although previous studies have performed on-farm evaluations for the control of airborne diseases such as foot-and-mouth disease (FMD) and influenza, disease control during the process of livestock and manure transportation has not been investigated thoroughly. The objective of this study is to predict common patterns of livestock-vehicle movement. Methods: Global positioning system (GPS) data collected during 2012 and 2013 from livestock vehicles on Jeju Island, South Korea, were analyzed. The GPS data included the coordinates of moving vehicles according to the time and date as well as the locations of livestock farms and manure-keeping sites. Data from 2012 were added to Esri software ArcGIS 10.1 and two approaches were adopted for predicting common vehicle-movement patterns, i.e., point-density and Euclidean-distance tools. To compare the predicted patterns with actual patterns for 2013, the same analysis was performed on the actual data. Results: When the manure-keeping sites and livestock farms were the same in both years, the common patterns of 2012 and 2013 were similar; however, differences arose in the patterns when these sites were changed. By using the point-density tool and Euclidean-distance tool, the average similarity between the predicted and actual common patterns for the three vehicles was 80% and 72%, respectively. Conclusions: From this analysis, we can determine common patterns of livestock vehicles using previous year's data. In the future, to obtain more accurate results and to devise a model for predicting patterns of vehicle movement, more dependent and independent variables will be considered.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.5
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• pp.186-201
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• 2021

As autonomous driving technology advances, the accuracy of the vehicle position is important for recognizing the environments around driving. Map-matching localization techniques based on high definition (HD) maps have been studied to improve localization accuracy. Because conventional map-matching techniques estimate the vehicle position based on an HD map reference dataset representing the center of the lane, the estimated position does not reflect the deviation of the lateral distance within the lane. Therefore, this paper proposes a localization system based on the reference lateral position dataset extracted using image processing and HD maps. Image processing extracts the driving lane number using inverse perspective mapping, multi-lane detection, and yellow central lane detection. The lane departure method estimates the lateral distance within the lane. To collect the lateral position reference dataset, this approach involves two processes: (i) the link and lane node is extracted based on the lane number obtained from image processing and position from GNSS/INS, and (ii) the lateral position is matched with the extracted link and lane node. Finally, the vehicle position is estimated by matching the GNSS/INS local trajectory and the reference lateral position dataset. The performance of the proposed method was evaluated by experiments carried out on a highway environment. It was confirmed that the proposed method improves accuracy by about 1.0m compared to GNSS / INS, and improves accuracy by about 0.04m~0.21m (7~30%) for each section when compared with the existing lane-level map matching method.