• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.95-105
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• 2002

Under a specific roadway alignment condition by design-speed standards, safety of the roadway is determined by an actual operating speed of a driver. This research takes first lanes of four-lane(hi-direction) rural highways as target facility. It also takes the straight and curved lanes of the selected highways for in-depth study. This study used NC-97 to detect speeds of passenger cars whose speeds are not affected by front vehicles. This research analyzed properties of 85th percentile operating speed at upstream of horizontal and through curves under various alignment conditions. The results show that 53∼65 Percent of drivers drive faster than the posted speed-limit (80KPH) by 14∼20 KPH on average. It also shows that the 85th-percentile operating speeds are the lowest at the middle point of curve length when curve radius is smaller. However, they are lowest at 1/4 point of curve length when curve radius is greater. Along roadways where curve radius is small, difference between upstream speed and the speed along the curve is considerably large. On the other hand. the speed difference is setting smaller as the curve radius is increasing. According to the results, significant variables affecting the 85th percentile operating speeds are curve radius and the 85th-Percentile operating speeds of upstream curves.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.1
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• pp.29-37
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• 2015

In this study, the estimation of axial load and total axial load was conducted using Bridge Weigh-in-Motion(BWIM) technique which generally consists of devices for measuring the strain induced in the bridge by the vehicles. axle detectors for collecting information on vehicle velocity and axle spacing. and data acquisition equipment. Vehicle driving test for the development of the BWIM system is necessary but it needs much cost and time. In addition, it demands various driving conditions for the test. Thus, we need a numerical-simulation method for resolving the cost and time problems of vehicle driving tests, and a way of measuring bridge response according to various driving conditions. Using a bridge model reflecting the dynamic characteristic contributes to increased accuracy in numerical simulation. In this paper, we conduct a numerical simulation which reflects the dynamic characteristic of a bridge using the Bridge Weigh-in-Motion technique, and suggest overload vehicle enforcement technology.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.68-80
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• 2016

This study proposes the traffic prediction and optimal traffic control system based on cell transmission model and genetic algorithm in cloud environment. The proposed prediction and control system consists of four parts. 1) Data preprocessing module detects and imputes the corrupted data and missing data points. 2) Data-driven traffic prediction module predicts the future traffic state using Multi-level K-Nearest Neighbor (MK-NN) Algorithm with stored historical data in SQL database. 3) Online traffic simulation module simulates the future traffic state in various situations including accident, road work, and extreme weather condition with predicted traffic data by MK-NN. 4) Optimal road control module produces the control strategy for large road network with cell transmission model and genetic algorithm. The results show that proposed system can effectively reduce the Vehicle Hours Traveled upto 60%.

• Journal of IKEEE
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• v.14 no.2
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• pp.58-63
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• 2010

In this paper, design and implementation of multi-modular robots of similar structure to the arthropods for rock path driving. Each module corresponds to an arthropod joint, which has an independent power supply and control equipment including drive and short-range Zigbee wireless communication that were implemented. On various directions and paths each module has the same driving direction and each module is controlled to operate or not by wireless communication. Depending on path condition, each module calculate the speed and torque and depending on the slope of a rough path, the number of active modules can be changed for the efficient driving on a variety of roads conditions. Experimental driving through rough road model, variable multi-module robot is implemented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.123-129
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• 2023

MIMO antenna is a field in which various researches have been actively conducted for a long time, and its design concept is universally well known. However, Unlike conventional MIMO antennas, MIMO antennas for autonomous driving radars, which have recently been attracting attention, are designed in W-band which is a millimeter wave band, and must also meet novel design conditions to satisfy the performance of autonomous driving radars. Therefore, a novel and different approach is required for the design and beam pattern verification of the MIMO antenna for autonomous driving radar. In this paper, a MIMO antenna is designed and the design process to satisfy the conditions of a W-band autonomous driving radar is introduced, and proposes a beam pattern verification method for a W-band MIMO antenna mounted on an autonomous driving radar system.

• Land and Housing Review
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• v.7 no.4
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• pp.307-314
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• 2016

Energy harvesting technique is to utilize energy that is always present but wasted. In this study, we have developed the energy harvester of the hybrid method utilizing both vibration and pressure of the vehicle traveling a road or parking lot. In the previous study, we have developed a prototype energy harvester, improved hybrid energy harvester, and developed a final product that offers improved performance in the hybrid module. The results were published in the previous paper. In this study, we installed the finally developed hybrid module in the actual parking lot. And we measured the power generation performance due to pressure and vibration, and the running speed of the vehicle when the vehicle is traveling. And we compared the results with those obtained in laboratory conditions. In a previous study performed in laboratory conditions the maximum power of the energy block was 1.066W when one single time of vibration, and 1.830W when succession with 5 times. On the other hand, in this study, we obtained the average power output of 0.310W when the vehicle is running at an average 5 km/h, 0.670W when at an average 10 km/h, and 1.250W when at an average 20 km/h, and 2.160W when at an average 5 km/h. That is, the higher the running speed of the vehicle has increased power generation performance. However, when compared to laboratory conditions, the power generation performance of the energy block in driving speed by 20km/h was lower than those in laboratory conditions. In addition, when compared to one time of vibration of laboratory conditions, power generation performance was higher when the running speed 20km/h or more and when five consecutive times in laboratory conditions, it was higher when the running speed 30km/h or more. It could be caused by a difference of load conditions between the laboratory and the actual vehicle. Thus, applying the energy block on the road would be more effective than that on the parking lot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.29-34
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• 2019

In this study, a gasoline test vehicle was evaluated for drive quality in emissions and fuel economy tests. The measurement results were compared with the manufacturer's suggested values to evaluate whether the tolerance ranges (fuel efficiency -5%, greenhouse gas +5%) were exceeded. We carried out tests with test subjects based on the SAE J2951 evaluation method. The test vehicle was a 2L gasoline vehicle. The drive following performance was found to increase under deliberate driving conditions and decreased in smooth driving conditions. As a result of the analysis of the drive following performance, the closer the value is to 1, the more accurate the driving is. (-) indicates harsh conditions, and (+) indicates gentle conditions. The basic data on the driver following between testers was obtained by analysis of the tests. The fuel efficiency correlation with the drive following performance within the target speed range of the fuel consumption mode. In the future, these measurement results can serve as key data for securing an exhaust gas database and fuel efficiency system for each measurement mode.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.34-37
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• 2002

본 연구에서는 표시형 디지털 정속주행 자동용접캐리지를 개발하고자 한다. 먼저, 용접조건을 결정하는 전류와 전압값의 입력과 출력을 디지털 입력스위치와 D/A 컨버터 출력회로를 구성하여 디지털 제어를 구성한다. 또한 디스플레이제어기의 구성은 정확한 용접조건에 의해서 용접할 수 있는 환경을 설정하여 용접의 효율성을 높이고자 한다. 시스템 제어기는 저가격과 출력전류의 특성이 개선된 RISK-Like 방식의 PIC16C74A를 이용하여 가격과 부피 및 노이즈에 강한 제어기를 구성하였다. 위빙 및 주행모터의 효율성과 응답특성을 개선하기 위해서 디지털 제어기(Digital PID Controller)를 설계하고. 이 제어기법을 이용하여 PWM인버터를 설계 및 제어 사용하여 용접 조건과 효율을 개선하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.6
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• pp.737-742
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• 2011

Navigation problems include the task of determining the control input under various constraints for systems such as mobile robots subject to uncertain disturbance. Such tasks can be modeled as constrained stochastic control problems. In order to solve these control problems, one may try to utilize the dynamic programming(DP) methods which rely on the concept of optimal value function. However, in most real-world problems, this trial would give us many difficulties; for examples, the exact system model may not be known; the computation of the optimal control policy may be impossible; and/or a huge amount of computing resource may be in need. As a strategy to overcome the difficulties of DP, one can utilize ADP(approximate dynamic programming) methods, which find suboptimal control policies resorting to approximate value functions. In this paper, we apply recently proposed ADP methods to a class of navigation problems having complex constraints, and observe the resultant performance characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.655-661
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• 2019

This study examined the change in driving performance according to the starting position of the rear diffuser of a vehicle. To accomplish this, the CATIA 3D design program was used to model the vehicle with reference to a commercial SUV vehicle and design the rear diffuser to start from 300, 400, and 500 mm from the rear tire. The flow and drag change were analyzed and the change in air flow was confirmed using Fluent, a flow analysis program at a vehicle traveling speed of 60, 100, and 140 km/h. The rear diffuser reduced the lift and drag forces compared to no diffuser regardless of the starting position. This is because if there is a rear diffuser, it will reduce the vortex phenomenon by suppressing the flow separation that occurs when air is drawn out from the rear portion of the vehicle. In this study, the starting point SP 400 was determined to be the optimal condition because the lift force was the smallest at SP 400 and the lift reduction effect was the best.