• Journal of Korean Society of Transportation
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• v.16 no.2
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• pp.67-76
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• 1998

본 연구는 현행 오르막차로 설계기준이 적정한지를 검증하고 오르막차로 설계기준 제시에 목적을 두고 있다. 오르막차로와 본선에 대한 현장의 속도분포와 화물차량의 합류형태를 바탕으로 오르막차로 설계기준을 검증하고 개발하였으며, 주요 연구결과를 요약하면 다음과 같다. 첫째, 설계속도 120km/h에서 화물차의 50백분위비율과 85백분율은 각각 66km/h와 76km/h로 나타났기 때문에 현행 설계속도 80km/h 이상의 구간에서 화물차의 허용최저속도를 60km/h로 규정하고 있는 것을 설계속도 기준을 세분화하여 설계속도가 100km/h 이상인 구간에서는 화물차의 허용최저 속도를 70km/h로 함이 타당한 것으로 도출되었다. 둘째, 설계속도 80km/h인 구간에서의 화물차 허용최저속도는 60km/h로 규정한 것이 적정하다고 확인되었다. 셋째, 설계속도 80km/h 미만의 구간에서 화물차의 허용최저속도는 설계속도에서 20km/h를 감한값을 사용하는데, 이 때 20km/h 감속을 한계속도 기준으로 사용하는 것이 적정하다고 확인되었다.

• Journal of Korean Society of Transportation
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• v.23 no.8 s.86
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• pp.153-162
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• 2005

This study is carried out to evaluate the sight distance change due to construction errors of vertical crest curves. Various design speeds and grades as well as various size of construction errors are incorporated in this study. After showing theoretical methodology numerical results are compared and analysed for the given ranges of parameters. New vertical curve change rate(m/%) is suggested to guarantee minimum sight distance under construction errors. As to the results, the reduction of sight distance are $2.8{\sim}21.3m$ at 120km/h, $2.0{\sim}15.1m$ at 100km/h, $1.4{\sim}10.6m$ at 80km/h, $1.0{\sim}7.5m$ at 60km/h $0.5{\sim}3.9m$ at 40km/h. Vortical curve change rates need to be increased about $6{\sim}25%$ to provide minimum stopping sight distance according to design speed.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.14 no.2
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• pp.60-67
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• 2008

Purpose : The purpose of this study is to investigate that the change of lower-limb muscle activity when normal gait and assistive gait of older. Methods : The selected subjects of this study were 11 older who be in good physical health and have not problem to gait and over 60 age to analyze the muscle activity. This study has been conducted to analyze the muscle activity of normal gait and assistive gait in unitary status without any contrast group. We have them gait condition of a gradient of 0% and velocity of 1km/h, 2km/h, 3km/h electrode were attached to the motor point of Rectus femoris, Hamstrings, Tibialis anterior, Calf muscle. When normal gait and assistive gait performs, there are meaningful differences that the muscle activity takes a small drop in Rectus femoris by 9.17% at 1km/h, 9.79% at 2km/h, 13.80% at 3km/h, hamstring by 14.78% at 1km/h, 17.82% at 2km/h, 17.26% at 3km/h, Tibialis anterior by 24.38% at 1km/h, 23.85% at 2km/h, 33.52% at 3km/h, Calf muscle by 13.68% at 1km/h, 16.70% at 2km/h, 18.37% at 3km/h(p<0.05). Results : They show the significant difference in statistical figure. We've received the significant through the comparison between normal gait and assistive gait. These results will be utilized for the preliminary date in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.202-210
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• 2019

This paper evaluated the performance of passenger vehicles with an AEB(Autonomous Emergency Braking) for various pedestrian-vehicle collision situations. The experiment was conducted at a speed of 30-60km/h on a 2017 3,000cc vehicle using a range of collision scenarios. The results showed that the test vehicle stopped before crashing a pedestrian dummy under all scenarios at 30km/h. The test vehicle reduced the speed but crashed the pedestrian dummy in all scenarios at 40-60km/h. From the paired t-test, there was a speed difference from the AEB system at a significant level of 0.05. In addition, the percentage of speed reduction was quite different for each scenario tested. It was concluded that the current AEB system can prevent pedestrian collisions at speed of 30km/h, but cannot prevent collisions with pedestrians at speed of 40-60 km/h.

• Korean Journal of Culture and Social Issue
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• v.17 no.1
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• pp.51-62
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• 2011

This study focused on the effects of median type on drivers' subjective sense of speed and the changes in this sense by driver age. Participants were 61 drivers: 20 young (aged 20-39 years), 19 middle-aged (40-59 years), and 22 older drivers (60+ years). The participants watched each of two driving scenarios, showing either a guardrail-equipped or a concrete median. The participants were asked to push a button when they perceived speeds of 60 km/h, 80 km/h, or 100 km/h. All drivers perceived higher speeds in the guardrail condition than in the concrete condition. Perceived speeds increased with driver age in both guardrail and concrete conditions. These results mean median type affects drivers' subjective sense of speed even as driver age increases, and that drivers' subjective sense of speed tends to increase with age.

• Journal of the Korean Regional Science Association
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• v.6 no.1
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• pp.57-68
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• 1990

The purpose of this study is to develop the models to predict the noise PCE (Passenger Car Equivalence) of large running vehicles through noise prediction models. The noises were measured at the distance of 7.5M, 11.0M, and 14.5M from the noise source with test vehicles running at the speed of 40 Km/h, 60 Km/h, and 80 Km/h while normal traffic were detoured. Total noise levels were measured while vehicles were running at given speeds, Engine noise level was considered as the noise of its idle running at the three vehicle speeds shown above friction noise level was ascertained by moving the vehicle at given speeds without the engin operating. The noise prediction models for each noise source were developed by factors which affect to the each noise level. As a result of this paper, the reduction of total vehicle noise by increasing the distance to the noise source from 10 M to 15 M is as much as that by dropping its speed from 60 Km/h to 40 Km/h. Also, the reduction of PCE of total noise of large vehicle by making the noise source to that by reducing its speed from 80 Km/h to 60 Km/h. Enging noise PCE, which is in range between 65 and 160, is larger than friction noise PCE which is in range 3.5 and 5.5. Engin noise is the main noise of the large vehicles while friction noise is that of the small vehicles. Machine noise for large vehicles, and engin noise for small vehicles should be tightly controlled to reduce the vehicle noise. A low noise engine and tire, and the shape of vehicle body are needed to be developed to reduce noise further.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.40-51
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• 2020

Much time has passed since Korea's expressway congestion-threshold speed was revised in 2011. In the meantime, various expressway environments have changed owing to improved performance of vehicles, expanded operations of transport competition (i.e., the KTX), and increased speed limits along some expressway sections. In addition, the speed that expressway users expect to travel at is also increasing. Therefore, through a survey, this study investigates expressway users' perceptions of congestion, and reviews the adjustment of the expressway speed congestion threshold by analyzing expressway traffic flow. One result of the survey confirms that the threshold speed expressway users consider to be congestion has slightly increased. Analyzing traffic and speed data through a K-means algorithm found that the threshold speed for congestion is 60 km/h. In addition, assuming the congestion threshold speed increase from 40 km/h to 50 km/h and 60 km/h, frequently congested expressway sections are identified, determining that 50 km/h is appropriate as a congestion threshold for proper expressway mobility management.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1715-1720
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• 2011

Studies suggested an increase in the competitiveness and roles of mainline railways like speed and accessibility improvement, as a fundamental direction of the National Transport Network Plan. At this point, topics presented especially for strengthening the role of human and environment centered transportation: as to the greatly improved speed competitiveness, there are an operational speed above 180km/h ~ 200km/h and traveling within 2 ~ 3 hours among big cities. As to accessibility improvement, there are accessibility to main railway stations within 30 minutes, and the improvement of accessibility, safety, eco-friendliness, amenity etc. As a part of these suggestions, field specific plans were proposed for the establishment of expressed mainline railway network in Korea such as train's, civil structures, trolley lines etc. In this paper we analyzed the conventional lines and systems to figure out whether to change details in terms of H/W of signaling system. Additionally, we reviewed the compatibility or difference of signalling system depending on train's speed. With this result, we deduced the number of virtual blocks specific to the speed of 180km/h, 200km/h and 230km/h, which were showed for the speed improvement considering each variable like blocks, braking distance etc. In this way, we suggested the railway signal system establishment plan considering safety operation.

• International Journal of Highway Engineering
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• v.12 no.1
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• pp.55-59
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• 2010

High VOC(Vehicle Operating Cost) is the main reason for the rehabilitation of paved road and VOC is composed of fuel consumption, lubricant oil consumption, parts consumption, etc. Fuel consumption is one of the largest components of VOC and the roughness of road represents the deterioration level of the road. For these reasons, the fuel consumption is measured for different IRI(International Roughness Index) in this study. The fuel consumption was measured by processing the voltage signal of fuel injector of vehicle and the speed was measured with GPS. The change rate of fuel consumption for different IRI can be calculated with the results of this test. It's concluded that fuel consumption(L/100km) of medium and large passenger car increases 7 times fast of the increase of IRI(m/km) around 3.5m/km in the speed range of 40 ~ 100km/h, and fuel consumption is the best at 60km/h.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.127-131
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• 2005

The running test for the Korean High Speed Train(HSR-350x) was performed at operating maximum sped(350km/h) at December 16th, 2004. HSR-350x had been fabricated in June, 2002 and the on-line test for the performance fo HSR-350x was started with 60km/h at August 19th, 2002. The success of running test at 350km/h is recorded the 4th rank in the world. In this paper, the measured results of the major performance(running behaviour, current collection, stability of rail and bridge) characteristics for HSR-350x are reviewed. All measured values are within the criteria.