• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.244-257
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• 2017

Traffic congestion occurs from drivers' human factors such as driver reaction time, reckless lane change, and inexperienced driving. When Automated Vehicles are introduced, human factors are excluded, resulting in increased average vehicle speed, stabilizing traffic flow, and increasing road capacity. This study analyzed traffic flow changes through traffic volume-speed-density plots, and increased road capacity due to Automated Vehicles. As a result of the analysis, when rate of automated vehicles gests higher, the traffic flow became stable. Additionally, it was analyzed that when all vehicles were automated, the road capacity increased by about 120 %. It is expected that there will be a positive expectation in terms of traffic congestion and traffic demand management due to the introduction of Automated Vehicles.

• International Journal of Highway Engineering
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• v.18 no.5
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• pp.117-125
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• 2016

PURPOSES : The density in uninterrupted traffic flow facilities plays an important role in representing the current status of traffic flow. For example, the density is used for the primary measures of effectiveness in the capacity analysis for freeway facilities. Therefore, the estimation of density has been a long and tough task for traffic engineers for a long time. This study was initiated to evaluate the performance of density values that were estimated using VDS data and two traditional methods, including a method using traffic flow theory and another method using occupancy by comparing the density values estimated using vehicular trajectory data generated from a radar detector. METHODS : In this study, a radar detector which can generate very accurate vehicular trajectory within the range of 250 m on the Joongbu expressway near to Dongseoul tollgate, where two VDS were already installed. The first task was to estimate densities using different data and methods. Thus, the density values were estimated using two traditional methods and the VDS data on the Joongbu expressway. The density values were compared with those estimated using the vehicular trajectory data in order to evaluate the quality of density estimation. Then, the relationship between the space mean speed and density were drawn using two sets of densities and speeds based on the VDS data and one set of those using the radar detector data. CONCLUSIONS : As a result, the three sets of density showed minor differences when the density values were under 20 vehicles per km per lane. However, as the density values become greater than 20 vehicles per km per lane, the three methods showed a significant difference among on another. The density using the vehicular trajectory data showed the lowest values in general. Based on the in-depth study, it was found out that the space mean speed plays a critical role in the calculation of density. The speed estimated from the VDS data was higher than that from the radar detector. In order to validate the difference in the speed data, the traffic flow models using the relationships between the space mean speed and the density were carefully examined in this study. Conclusively, the traffic flow models generated using the radar data seems to be more realistic.

• Korean Journal of Environment and Ecology
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• v.21 no.6
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• pp.526-535
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• 2007

This study was conducted at the Civilian Controlled Zone(CCZ) in the Cherowon from February to March 2004 to investigate the reaction to the vehicles of Red-crowned Cranes(RCC) and White-naped Cranes(WNC) and trade-off of the vehicle interruption with food resources. The for-aging distance from the road of WNC was much closer than that of RCC. The large flocks of cranes' average feeding distance from the road was farther than small flocks of cranes in both species. Cranes showed the reaction, such as alert, walking, running and flying against the vehicle stop and were more sensitive as they were close to the road. The reacting time to the stopping vehicle were reduced as it was farther from the road. The distance of about 250m was a reaction threshold distance against the vehicle stop to both species. The reacting time in the same distance was not different in relation to the traffic volume, but large traffic volume tended to cause cranes to stay far away from the road and not to feed themselves near a traffic congested area. The reason cranes fed themselves on fallen rice grains in spite of the vehicular traffic interruption factor was that there was a high density of the fallen rice grains remaining at the area near a road.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1055-1067
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• 1994

This paper is presented to perform linear dynamic analysis of bridges due to vehicle moving on bridges. The road surface roughness and bridge/vehicle interaction are also considered. The bridge and vehicle are modeled as 3-D bridge and vehicle model, respectively. The road surface roughness of the roadway and bridge decks are generated from power spectral density(PSD) function for good road. The PSD function proposed by C.J. Dodds and J.D. Robson is used to describe the road surface roughness for good road condition. The vehicles are modeled as two nonlinear vehicle model with 7-D.O.F of truck and 12-D.O.F of tractor-trailer and the equations of motion of the vehicles are derived using Lagrange's equation. The main girder and concrete deck are modeled as beam and shell element, respectively and rigid link is used between main girder and concrete deck. The equations of motion of the vehicles are solved by Newmark ${\beta}$ method and the equations of the motion of the bridges are solved by mode-superposition procedures. The validity of the proposed procedure is demonstrated by comparing the results with the experimental data reported by the AASHO Road Test. The comparison shows that the agreement between experiment and theory is quite satisfactory.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.163-169
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• 1997

Due to the increasing of the number of cars and bad road conditions, car accidens are increasing every you in Korea. When a person meets a car accident, it is necessary for him to analyze and determine whether applying insurance or not, because standard discount rate and special increasing rate change with accident types and the amount of accident expenditure. When we consider insurance rate that includes more then ten elements, we need a decision making, In this paper, S insurance company investigated previous car causers in 1988, 1989, 1990 to 1996 with 600,000 real data. We investigate probability density functions and cumulative distribution functions for each year using ARENA software. We can apply the results of this study to various accidents that occur under uncertainty in our life. I hope that this paper contribute to strengthening competitive power of companies and developing new insurance rate systems in future.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.553-556
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• 2004

We present a new model for the generation of magnetic fields on large scales occurring at the end of cosmological reionisation. The inhomogeneous radiation provided by luminous sources and the fluctuations in the matter density field are the major ingredients of the model. More specifically, differential radiation pressure acting on ions and electrons gives rise to electric currents which induce magnetic fields on large scales. We show that on protogalactic scales, this process is highly efficient, leading to magnetic field amplitudes of the order of $10^{-1l}$ Gauss. While remaining of negligible dynamical impact, those amplitudes are million times higher than those obtained in usual astrophysical magnetogenesis models. Finally, we derive the relation between the power spectrum of the generated field and the one of the matter density fluctuations. We show in particular that magnetic fields are preferably created on large (galactic or cluster) scales. Small scale magnetic fields are strongly disfavoured, which further makes the process we propose an ideal candidate to explain the origin of magnetic fields in large scale structures.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.37-44
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• 2013

PURPOSES: This study is to develop the deduct value curves for the calculation of pavement condition index of asphalt airfield pavement. METHODS: To develop the deduct value curves of asphalt airfield pavement, panel rating was conducted to decide the pavement condition based on pavement distress type, severity, and density. RESULTS: Results show that standard deviation of deduct values by panel rating is increased at higher severity level and as damage density increases. The deduct value of alligator cracking show the highest. CONCLUSIONS: The deduct value curves based on panel rating could be used without existing problems which were occurred in Shahin's method.

• Structural Engineering and Mechanics
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• v.59 no.6
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• pp.1019-1035
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• 2016

This paper proposes a new foundation model called "Dynamic foundation model" for the dynamic analysis of plates on foundation subjected to a moving oscillator. This model includes a linear elastic spring, shear layer, viscous damping and the special effects of mass density parameters of foundation during vibration. By using finite element method and the principle of dynamic balance, the governing equation of motion of the plate travelled by the oscillator is derived and solved by the Newmark's time integration procedure. The accuracy of the algorithm is verified by comparing the numerical results with the other numerical results in the literature. Also, the effects of mass and damping ratio of system components, stiffness of suspension system, velocity of moving oscillator, and dynamic foundation parameters on dynamic responses are investigated. A very important role of these factors will be shown in the dynamic behavior of the plate.

• Electrical & Electronic Materials
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• v.13 no.12
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• pp.6-9
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• 2000

Over the years of decades, the memory technology has progressed a long, marble way. As we have evidenced from the Intel's 1Kb DRAM in 1970 to the Gigabit era of 2000's, the road further ahead towards the Terabit era will be unfolded. The technology once perceived inconceivable is in realization today, and similarly roadblocks as we know of today mayvecome trivial issues for tomorrow. For the inquiring mind, the question is how the "puzzle"of tomorrow's memory technology is pieced-in today. The process will take place both in evolutionary and revolutionary ways. Among these, note-worthy are the changes in DRAM architecture and the cell process technology. In this paper, some technical approaches will be discussed to bring these aspects into a general overview and a per-spective with possibilities for the new memory technology will be presented.presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.17-20
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• 2000

Over the years of decades, the memory technology has progressed a long, marble way. As we have evidenced from the Intel’s 1Kb DRAM in 1970 to the Gigabit era of 2000’s, the road further ahead towards the Terabit era will be unfolded. The technology once perceived inconceivable is in realization today, and similarly roadblocks as we know of today may become trivial issues for tomorrow. For the inquiring mind, the question is how the “puzzle” of tomorrow’s memory technology is pieced-in today. The process will take place both in evolutionary and revolutionary ways. Among these, note-worthy are the changes in DRAM architecture and the cell process technology. In this paper, some technical approaches will be discussed to bring these aspects into a general overview and a perspective with possibilities for the new memory technology will be presented.