• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.4
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• pp.167-189
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• 2022

In the case of SAE autonomous driving levels 2 and 3, since complete autonomous driving is impossible, the take-over process is essential, and take-over time(TOT) is the most important factor in determining the safety of the autonomous driving system. Accordingly, research on TOT is being actively conducted, but each research is independently conducted and general conclusions that integrate various research results are required. Therefore, in this study, the factors affecting TOT were analyzed using meta-analysis, which integrates the results of individual studies and presents an integrated opinion. As a result of meta-analysis, a total of 10 influencing factors were selected, and most of them were related to the non-driving related task(NDRT) type. In addition, implications for the future research direction of take-over and NDRT were presented.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.6
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• pp.35-41
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• 2010

The ubiquitous-transportation sensor network (u-TSN) system is a next generation transportation system that provides traffic information through analysis and processing periodic information from vehicles. In this paper, we propose the adequate transmission scheme from vehicles for collecting vehicular information. The conventional scheme is transmitting each vehicle information every 0.1s. A variable transmission period scheme is proposed in this paper according to vehicle speed. The proposed and conventional schemes are compared with computer simulations.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.95-98
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• 2002

This paper presents a study on DSP(TMS320F240) controller design for multi-axes transportation system using BLDC servo motor. This BLDC servo motor controller was realized with DSP(Digital Signal Processor) and IPM (Intelligent Power Module). The multi-axes transportation system needs torque, speed, position control of servo motor for variable action. This paper implements those servo control with vector control and space vector modulation technique. As CPU of controller DSP(TMS320F240) is adopted because, it has PWM(Pulse Width Modulation) waveform generator, A/D(Analog to Digital) converter, SPI(Serial Peripheral Interface) port and input/output port etc. The controller of multi-axes transportation system consists of 3-level hierarchy structure that main host PC manages three sub DSP system which transfer downword command and are monitoring the states of end servo controllers. Each sub DSP system operates eight BLDC servo controllers which control BLDC servo motor using DSP and IPM Between host system and middle digital signal processor communicate with RS-422, between main processor and controller communicate with SPI port.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.31-39
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• 2014

Recently, as Intelligent Transportation System (ITS) and self-driving system become influential in the ground transportation system, automotive radar systems have been actively studied among the various radar systems to implement the vehicle collision detection system and distance measurement system between vehicles. Most of the automotive radars are Frequency Modulated Continuous Wave (FMCW) radar type which can calculate distance and velocity of target by estimating the frequency difference between the transmitted signal and received signal. Therefore, accurate frequency estimation is very important in the FMCW radar system. For this reason, to improve the measurement accuracy of the FMCW radar, Reverse Directional FRI (RD-FRI) Super-Resolution technique which has high frequency estimation accuracy is applied to the FMCW radar system. The feasibility of the proposed technique is evaluated with simulation results and compared with FFT and conventional Super-Resolution techniques. The simulation results show that the proposed technique estimates the frequency with high accuracy and the distance with centimeter accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1186-1197
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• 2000

In this paper, we investigated performance for 5.8GHz Dedicated Short Range Communication(DSRC) packet communication system which will be applied to domestic Intelligent Transportation System(ITS) services and analyzed modulation technique and interference cancellation method to improve performance in physical layer. We presented the most suitable DSRC uplink protocol to apply to multiple access protocol for DSRC system. Finally, we presented channel model to estimate performance between Roadside Unit(RSU) and Onborad Unit(OBE), and showed their validity through the result of numerical analysis.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.894-897
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• 2014

The speed of processes and the extremely large amount of data to be used in Intelligence Transportations System (ITS) cannot be handling by humans without considerable automation. However, it is difficult to develop software with conventional fixed algorithms (hard-wired logic on decision making level) for effectively manipulate dynamically evolving real time transportation environment. This situation can be resolved by applying methods of artificial intelligence and data mining that provide flexibility and learning capability. This paper presents a brief introduction of data mining and artificial intelligence (AI) applications in Intelligence Transportation System (ITS), analyzing the prospects of enhancing the capabilities by means of knowledge discovery and accumulating intelligence to support in decision making.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.58-72
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• 2018

Ganghwa has met a new development period in land use and infrastructure based on the 4th National Development Planning, however the public transportation system is not systematically operated yet. This paper analyzes the bus trip pattern in Ganghwa using transportation card data during a week. The result indicates that average 7,100 people use buses a day and the most frequent use occurred in Friday. Clear peak-hours between 7 and 8 A.M. and between 4 and 5 P.M. were appeared due to commuting and school trips. According the result of regression analysis, population and the number of hospitals and schools area showed positive relationships with but trips reflecting regional characteristics. The research contributes to providing basic data for constructing an efficient public transportation system in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.535-538
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• 2012

Recently active research for ITS(Intelligent Transportation System) helps to build for next generation traffic information system at information society. Build the system for sensing a vehicle speed and traffic information on the road. Provide collected data to driver, flow of overall traffic impacts have a good influence. In this study, research for building the platform and development algorithm that provided from other source processing real-time traffic data provides a more reliable real-time traffic data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2046-2052
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• 2016

Ramp metering is one of the most efficient and widely used control methods for an intelligent transportation management system on a freeway. Its objective is to control and upgrade freeway traffic by regulating the number of vehicles entering the freeway entrance ramp, in such a way that not only the alleviation of the congestion but also the smoothing of the traffic flow around the desired density level can be achieved for the maintenance of the maximum mainline throughput. When the cycle of the signal detection is larger than that of the system process, the density tracking problem needs to be considered in the form of the discrete-time system. Therefore, a discrete-time sliding mode control method is proposed for the ramp metering problem in the presence of both input constraint in the on-ramp and exogenous disturbance in the off-ramp considering the random behavior of the driver. Simulations were performed using a validated second-order macroscopic traffic flow model in Matlab environment and the simulation results indicate that proposed control method can achieve better performance than previously well-known ALINEA strategy in the sense that mainstream flow throughput is maximized and congestion is alleviated even in the presence of input constraint and exogenous disturbance.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.5
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• pp.635-641
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• 2006

Ship's collision avoidance is a skill that masters of merchant marine vessels have acquired through years of experience and that makes them feel at ease to guide their ship out from danger quickly compared to inexperienced officers. Case based reasoning (CBR) uses the same technique in solving tasks that needs reference from variety of situations. CBR can render decision-making easier by retrieving past solutions from situations that are similar to the one at hand and make necessary adjustments in order to adapt them. In this paper, we propose to utilize the advantages of CBR in a support system for ship's collision avoidance while using fuzzy algorithm for its retrieval of similar navigational situations, stored in the casebase, thus avoiding the cumbersome tasks of creating a new solution each time a new situation is encountered. There will be two levels within the Fuzzy-CBR. The first level will identify the dangerous ships and infer the new case. The second level will retrieve cases from casebase and adapt the solution to solve for the output. While CBR's accuracy depends on the efficient retrieval of possible solutions to be adapted from stored cases, fuzzy algorithm will improve the effectiveness of solving the similarity to a new case at hand.