• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.28-41
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• 2022

A road system with CV(Connected Vehicle)s, which is often referred to as a cooperative intelligent transportation system (C-ITS), provides various road information to drivers using an in-vehicle warning system. Road environments with CVs induce drivers to reduce their speed or change lanes to avoid potential risks downstream. Such avoidance maneuvers can be considered to improve driving behaviors from a traffic safety point of view. Thus, empirically evaluating how a given in-vehicle warning information affects driving behaviors, and monitoring of the correlation between them are essential tasks for traffic operators. To quantitatively evaluate the effect of in-vehicle warning information, this study develops a method to calculate compliance rate of drivers where two groups of speed profile before and after road information is provided are compared. In addition, conventional indexes (e.g., jerk and acceleration noise) to measure comfort of passengers are examined. Empirical tests are conducted by using PVD (Probe Vehicle Data) and DTG (Digital Tacho Graph) data to verify the individual effects of warning information based on C-ITS constructed in Seoul metropolitan area in South Korea. The results in this study shows that drivers tend to decelerate their speed as a response to the in-vehicle warning information. Meanwhile, the in-vehicle warning information helps drivers to improve the safety and comport of passengers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.10
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• pp.967-973
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• 2014

WAVE (Wireless Access in Vehicular Environments) communications is the core technology for C-ITS (Cooperative-Intelligent Transportation System) which communicates with the road infrastructure and other vehicles to exchange traffic information and service while driving. In this paper, to analyze the performance degradation according to the distance between WAVE communication terminals, we derived the formulas for the locations of down-fade and up-fade points by using the two-ray ground reflection model, and verified these theoretical results by comparing with those of RSSI (Receiver Signal Strength Indicator) measurements. In addition, to solve the problem of down-fade, we suggested the WAVE communication with the antenna diversity and experimentally confirmed the performance improvement in the highway LOS (Line Of Sight) environments.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.18-29
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• 2015

The purposes of this research and development are as follows: first, to provide pleasant driving environments inside tunnels; second, to improve the current illumination environments lacking in diffusion luminance meters to meet tunnel lighting standards; and, third, to reduce the consumption of tunnel lighting energy accounting for approximately 65% of tunnel maintenance costs because of inadequate visual environments and tunnel operations. Further details are listed below. Firstly, an image luminance meter for tunnels that can implement the L20-method which is a tunnel luminance method that follows the international standards of CIE88, which was developed in order to improve and change the existing illumination-based tunnel lighting operation system to a luminance-based system. (The margin of error of below 5% according to the results of a test by an authorized agency and field test). Secondly, early illumination control is possible since the lighting control system that can be operated based on luminance enables interlocking control of the inside and outside of a tunnel using ethernet communication. Thirdly, guidelines for field application of the system are proposed. In addition, the luminance inducers of tunnels are found and the reflexibility of each facility that may reduce luminance of the boundaries is also proposed. Fourthly, as a result of a test bed, power consumption of luminance-based lighting operations decreased by 15.6% compared to illumination-based operations. Applying the feedback controls and maintenance factors of internal/external luminance meters, it reduced by 36.4%. Therefore, we became able to provide a luminance-based lighting operation system that complies with tunnel lighting design standards and provides a visual environment for drivers.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.76-80
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• 2017

With the fast growing popularity of small UAVs (Unmanned Aerial Vehicles), recent UAV systems have been designed and utilized for the various field with their own specific purposes. UAVs are opening up many new opportunities in the fields of electronics, sensors, camera, and software for pilots. Increase in awareness and mission capabilities of UAVs are driving innovations and new applications driven with the help of low cost and its capability in undertaking high threat task. In particular, small unmanned aerial vehicles should fly in environments with high probability of unexpected sudden change or obstacle appearance in low altitude situations. In this paper, current researches regarding techniques of autonomous flight of smal UAV systems are introduced and we propose a draft idea for planning paths for small unmanned aerial vehicles in adversarial environments to arrive at the given target safely with low cost sensors.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.1-9
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• 2009

A parking-assist system is defined that a driver adjusts vehicle velocity through brake pedal operation and parking-assist system controls the motion of the vehicle to follow a collision-free path. In this study, a motion control algorithm using Fuzzy inference is proposed to track a maneuvering clothoid parallel path. Simulations are performed under SIMULINK environments using MATLAB and CarSim for a vehicle model. As the vehicle model in MATLAB a bicycle model is used including lateral dynamics. The simulation results show that the path tracking performance is satisfactory under various driving and initial conditions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.2
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• pp.19-26
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• 2014

With the radical changes and advancements of industrial economy, it is required to secure product competitiveness through technological innovations to overcome uncertain environments and generate a driving force for sustainable growth. So the Korea government introduced the superior product selection system in 1996 and has granted such incentives as priority purchasing and contracts the products of SME whose technological capabilities have passed the screening criteria. After analyzing the ambiguity of the evaluation procurement used in designation of excellent product, this study proposed seven detailed indexes for evaluation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.289-289
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• 2009

The series hybrid propulsion system in bimodal tram consists of CNG engine, generator, inverter, motor and battery as main components. Among them, battery is very important thing to make a hybrid bimodal tram more efficient in driving. Battery pack is composed of 168 LPB(lithium polymer battery) cells, 650Vdc-300A. LPB should be treated with a good consideration in both temperature and overvoltage. This paper had analyzed and investigated the thermal flow and distribution of LPB module(l4 LPB cells) and Pack in simulated environments by commercial thermal analysis tool.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.134-136
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• 2008

In recent years, the switched reluctance motor have been used many industrial application because of its cost advantage. SRM drivers are accomplished by switching the phase currents on and off synchronously with the rotor position which is fed back to the controller by position may deteriorate in harsh environments and increase the size and cost of the SRM drive system. This paper proposes a position sensorless method that is based on impressed pulse voltage using impressed at unenergised phases to estimate the rotor position. The current value by impressed pulse voltage compare with the threshold value. The rotor position can be estimated by observing the current value. Finally, simulation results compare with the sensor type SRM and confirm the proposed method to be useful.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.508-510
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• 2004

In this paper, we proposed the GPS position data correction method for autonomous land navigation using vanishing point property and a monocular vision system. Simulations are carried out over driving distances of approximately 60 km on the basis of realistic road data. In straight road, the proposed method reduces GPS position error to minimum more than 63% and positioning errors within less than 0.5m are observed. However, the average accuracy of the method is not presented. because it is difficult to estimate it in curve road or other road environments.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.180-187
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• 1998

The stability and theoretical performance limits of the feedback controlled force reflecting haptic manipulator have been discussed. All the virtual environment which interact physically with the haptic system have its own stable performance limit. Three different realization of the interfaces have been compared using the driving point admittance. The haptic system which is separated from the human hand or finger is superior to its stable interaction provided that there is a means to apply a direct damping between the haptic manipulator and the human finger Electro-magnetic force is used for its digital implementation of the simple separated type haptic device. The stable limits of a virtual wall is calculated and experimental results show that there is performance limits in this implementation.