• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2298-2319
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• 1999

In this paper, we propose a new moving mobile base station (MMBS) scheme for very low power and micro-size RMIMS (radio-interfaced micro information monitoring system) terminals. RMIMS terminals can be used in various application service areas such as pollution monitoring, environment surveillance, traffic monitoring, emergency monitoring (e.g., building, bridge, railroad breakdown), security monitoring (e.g., theft, alarm) and military application. For these applications based on wireless transmission technologies, sensor type RMIMS terminals must satisfy low cost and low power design (e.g., solar power, life limited battery) requirement. In RMIMS terminal design, this low power requirement limits transmission range of uplink or reverse link and means small cell size. Also these applications using RMIMS terminals may have a little bit non real-time traffic characteristic and low scattering density in service area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.663-669
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• 2011

In this study, the optimal length of left-turn lane in permissive left-turn signal system at the signalized intersection which has a left-turn bay is estimated. It is a simulation analysis using the queueing theory that estimate the length of left-turn lane. Traffic density conform to the standards of operating a permissive left-turn system of the Practical Manual Traffic Safety Facilities. And each of a left-turn arrival rate, a left-turn service rate, left-turn average queueing time, for green time average queueing vehicle, for red time average queueing vehicle and average queueing vehicle cycle is calculated. As a result of this study, we would learn how much the space should be secured at the signalized intersection which has a left-turn bay. The methodology using the queueing theory to work out the optimal length of waiting lane in the permissive left-turn signal system was presented.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.359-364
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• 2004

When sea going vessel approaches her destination port, marine traffic density is increased, especially, the marine traffic is concentrated in the entrance channel and the fairway in the inner harbour is more narrow. Therefore, special navigational rules for preventing collision at sea is needed in the inner harbour. Hence there are the rules in The Public Order in Open Port Act in Korea But, in the case of conflict of navigational rule concerned, it is possible to be raised a question that which rule shall be applied preferentially. Also, it is necessary to understand the exact meaning of the navigational rules in The Public Order in Open Port Act. Because the misunderstanding of the rule is caused the collision Therefore, this paper aims to discuss the exact meaning of the navigational rule concerned in the view of legal basis and suggest the principles for a proper application of it.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3B
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• pp.165-173
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• 2012

In this paper, we propose a random backoff scheme for Emergency Warning Messages (EWMs) in the vehicle-to-vehicle environment. The EWMs are disseminated from a vehicle that detects an emergency situation to other vehicles in a multi-hop fashion. Since the vehicle-to-vehicle communication based on IEEE 802.11 adapts CSMA/CA, the density of vehicles increase the probability of collisions between transmissions. Moreover, in the presence of background traffic, the EWM should have a higher priority than that of other messages in neighboring vehicles. To that end, we propose the Distant-Dependent Adaptive Backoff (DDAB) scheme, which set a different contention window for random backoff depending on the distance from the sender to the receiver. In the case when a vehicle is expected to located in the outskirts of the communication boundary, the proposed scheme makes the contention window size small in order to compete the background traffic transmission. Otherwise the contention window is set to a large number to reduce the collision possibility among the EWM transmissions. Via simulations, we show that the proposed scheme performs better than the previous schemes for EWM.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.119-128
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• 2004

With the growing traffic density and increasing comfort requirements, the automation of the drive train will gain importance in vehicles. The automatic clutch actuation relieves the drivers especially in urban driving and stop-and-go traffic conditions. This paper describes the dynamic modeling of a clutch actuator and clutch spring. The dynamic model of the clutch system is developed using MATLAB/Simulink, and evaluated by experimental data using a test rig. This performance simulator is useful to develop the clutch-by-wire (CBW) system for an automated manual transmission (AMT). The electro-mechanical type CBW system is also implemented as an automatic clutch for AMT. The prototype of CBW system is designed and implemented systematically, which is composed of an electric motor, worm gear and slider-crank mechanism. The test rig is developed to perform the basic function test of the automatic clutch, and the developed prototype is validated by the experimental data on the test rig.

• Journal of the Korean Chemical Society
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• v.9 no.3
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• pp.116-120
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• 1965

The degree of atmospheric pollution from automobile engine exhausts has been measured at 1-ga, Eulchiro, Jung-ku, one of the heaviest traffic junctions in Seoul. By determining the concentrations of Pb, $SO_2, NO_2, NO, CO \;and\; CO_2$ in atmospheric air measured are as follows: Pb, $21{\sim}2 {\mu]g./m^3.;\;SO_2,\;0.33{\sim}0.001\;ppm.;\;NO_2,$ $0.20{\sim}< 0.01\;ppm.;\;NO,\;1.30{\sim}0.02\;ppm.;\;CO,\;40{\sim}<\;5ppm$.; and $CO_2,\;0.040{\sim}0.034%$. The mean concentrations determined are as follows: Pb, $11 {\mu}g./m^3.; SO_2, 0.08 ppm.; NO_2,$ 0.09 ppm.; NO, 0.37 ppm.; CO, 16 ppm. and $CO_2,$ 0.038%. Generally, the concentrations of Pb, $NO_2, NO, CO\; and\; CO_2$ are approximately proportional to the traffic density, vehicles passing per hour.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.301-306
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• 2008

Drivers are becoming more fatigued and uncomfortable with increase in traffic density, and this condition can lead to slower reaction time. Consequently, they may face the danger of traffic accidents due to their inability to cope with frequent gear shifting. To reduce this risk, some drivers prefer automatic transmission (AT) over manual transmission (MT). The AT offers more superior drivability and less shifting shock than the MT; therefore, the AT market share has been increasing. The AT is controlled by an electronic control unit (ECU), which provides better shifting performance. The transmission control unit (TCU) is a higher-value-added product, so the companies that have advanced technologies end to evade technology transfer. With more cars gradually using the ECU, the TCU is expected to be faster and more efficient for organic communication and arithmetic processing between the control systems than the l6-bit controller. In this paper, the model of an automatic transmission vehicle using MATLAB/Simulink is developed for the Hardware in-the-Loop (HIL) simulation with a 32-bit embedded system, and also the AT control logic for shifting is developed by using MATLAB/Simulink. The developed AT control logic, transformed automatically by real time workshop toolbox, is loaded to a 32-bit embedded system platform based on Freescale's MPC565. With both vehicle model and 32-bit embedded system platform, we make the HIL simulation system and HIL simulation of AT based on real time operating system (RTOS) is performed. According to the simulation results, the developed HIL simulator will be used for the performance test of embedded system for AT with low cost and effort.

• Smart Structures and Systems
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• v.17 no.6
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• pp.1087-1105
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• 2016

Traffic load and volume is one of the most important physical quantities for bridge safety evaluation and maintenance strategies formulation. This paper aims to conduct the statistical analysis of traffic volume information and the multimodal modeling of gross vehicle weight (GVW) based on the monitoring data obtained from the weigh-in-motion (WIM) system instrumented on the arch Jiubao Bridge located in Hangzhou, China. A genetic algorithm (GA)-based mixture parameter estimation approach is developed for derivation of the unknown mixture parameters in mixed distribution models. The statistical analysis of one-year WIM data is firstly performed according to the vehicle type, single axle weight, and GVW. The probability density function (PDF) and cumulative distribution function (CDF) of the GVW data of selected vehicle types are then formulated by use of three kinds of finite mixed distributions (normal, lognormal and Weibull). The mixture parameters are determined by use of the proposed GA-based method. The results indicate that the stochastic properties of the GVW data acquired from the field-instrumented WIM sensors are effectively characterized by the method of finite mixture distributions in conjunction with the proposed GA-based mixture parameter identification algorithm. Moreover, it is revealed that the Weibull mixture distribution is relatively superior in modeling of the WIM data on the basis of the calculated Akaike's information criterion (AIC) values.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.149-155
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• 2008

The road construction, as part of effort to ease the worsening traffic, has been underway throughout the nation, while the existing road has been increasingly losing its load carrying capacity due to such factors as heavy traffic and weathering. In the case of site, the soil type, plasticity index, and specific gravity were SC, 12.2%, and 2.66, respectively. The maximum dry density, optimum moisture content and modified CBR were $1.895g/cm^3$ (Modified Compaction D), 13.6%, and 16.2%, respectively. A correlation of coefficient expressed good interrelationship by 0.90 between the CBR estimated from a dynamic penetration index of dynamic cone penetrometer test and a deformation modulus converted from a dynamic deflection modulus obtained from a portable FWD test.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.107-117
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• 2008

OBE(On Board Equipment) of IR(Infrared)/RF(Radio Frequence)-DSRC(Dedicated Short Range Communication) are set up 1.25 million cars because Korea Highway Cooperation supplied in HiPass(Domestic Electronic Toll Collection System). But this DSRC system has strength and weakness of service for BIS(Bus Information System) or UTIS(Urban Traffic Information System) because BIS and UTIS are required vary high communication's performance and management. In this paper, Efficiency of IR/RF-DSRC is analyzed performance of MAC(Medium Access Control) by computer simulation for services of BIS or UTIS, so Suggested to be commensurated with medium of there service. Specially, DSRC is needed high mobility and throughput in the vary short communication range, so Analysed the transmission rate of data in each communication medium over the specific character of the MAC frame.