• Korean Journal of Culture and Social Issue
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• v.17 no.4
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• pp.381-393
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• 2011

Eco driving is a strategy to reduce energy consumption and greenhouse gas emissions from motor vehicle. However, it has not received much attention until recently. Psychological studies on this issue have been limited and the majority of existing studies have primarily been based on engineering and educational approaches. This study examined the effects of a self-management technique on two driving behaviors: speeding and putting the gears in neutral while waiting at the signal. The self-management technique consisted of three behavior interventions: goal-setting, self-monitoring, and reward. Three drivers participated in this study. An AB multiple baseline design across participants was adopted. Results showed that the self-management technique was effective in increasing both driving behaviors. Implications of the present findings and suggestions for future research were discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.571-578
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• 2023

In this paper, we propose a low EMI data transmitter employing a delay-locked loop for vehicles. For the low EMI characteristic, the transmitter has been designed to have low slew rate and employs the delay-locked loop to correct the amount of change in the slew rate due to process variations. According to simulation results, the proposed transmitter which the delay-locked loop has smaller slew rate change as compared to the conventional transmitter. The proposed circuit has been designed with a 65nm process technology and the data rate is 20Mbps with a supply voltage of 1.1V. As compared to a conventional transmitter, the proposed transmitter shows that variations of the slew rate become 53.6% lower in a fast condition and 13.07% lower in a slow condition.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.761-768
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• 2022

In the hope of realizing carbon neutrality, Korea has established the goal of expanding the supply of hydrogen electric vehicles through a roadmap to revitalize the hydrogen economy. A prerequisite for successful supply expansion is securing the safety of hydrogen electric vehicles. Certain parts, such as the hydrogen transport pipe and tank, in hydrogen electric vehicles are exposed to high-pressure hydrogen gas over long periods of time, so the hydrogen enters the grain boundary of material, resulting in a degradation of the parts referred to as hydrogen embrittlement. In addition, since the safety of parts utilizing hydrogen varies depending on the type of material used and its environmental characteristics, the necessity for the enactment of a hydrogen embrittlement regulation has emerged and is still being discussed as a Global Technical Regulation (GTR). In this paper, we analyze a hydrogen compatibility material evaluation method discussed in GTR and present a direction for the development of Korean-type hydrogen compatibility material evaluation methods.

• Journal of IKEEE
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• v.27 no.1
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• pp.1-11
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• 2023

Path driving tests are necessary for the development of self-driving cars or robots. These tests are being conducted in simulation as well as real environments. In particular, for development using reinforcement learning and deep learning, development through simulators is also being carried out when data of various environments are needed. To this end, it is necessary to utilize not only manually designed paths but also various randomly and automatically designed paths. This test site design can be used for actual construction and manufacturing. In this paper, we introduce a method for randomly generating a driving test path consisting of a combination of arcs and segments. This consists of a method of determining whether there is a collision by obtaining the distance between an arc and a line segment, and an algorithm that deletes part of the path and recreates an appropriate path if it is impossible to continue the path.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.291-310
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• 2023

This study explores the factors which affect user acceptance for Robo Taxi, an electricity-based Autonomous Vehicles based on a Value based Adoption Model. The three main factors of benefit (usefulness and enjoyment), sacrifice (technicality and perceived fee level), and user experience about mobility services such as car sharing, taxi, and autonomous vehicles, were finally selected as independent variables as a influential factors on perceived values and adoption intention of Robo taxi. The study found that usefulness, enjoyment, and perceived fee had a significant effects on adoption intention, and some user experiences had a significant effect on benefit factors. This study has important implications for incorporating the Value-based Adoption Model results into the service design for the activation of Robo taxi, and furthermore, they can provide a theoretical basis for effective use of the research findings.

• Journal of Astronomy and Space Sciences
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• v.40 no.2
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• pp.79-88
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• 2023

On Aug. 4, 2022, at 23:08:48 (UTC), the Korea Pathfinder Lunar Orbiter (KPLO), also known as Danuri, was launched using a SpaceX Falcon 9 launch vehicle. Currently, KPLO is successfully conducting its science mission around the Moon. The National Aeronautics and Space Administration (NASA)'s Deep Space Network (DSN) was utilized for the successful flight operation of KPLO. A great deal of joint effort was made between the Korea Aerospace Research Institute (KARI) and NASA DSN team since the beginning of KPLO ground system design for the success of the mission. The efficient utilization and management of NASA DSN in deep space exploration are critical not only for the spacecraft's telemetry and command but also for tracking the flight dynamics (FD) operation. In this work, the top-level DSN interface architecture, detailed workflows, DSN support levels, and practical lessons learned from the joint team's efforts are presented for KPLO's successful FD operation. Due to the significant joint team's efforts, KPLO is currently performing its mission smoothly in the lunar mission orbit. Through KPLO cooperative operation experience with DSN, a more reliable and efficient partnership is expected not only for Korea's own deep space exploration mission but also for the KARI-NASA DSN joint support on other deep space missions in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.91-104
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• 2022

The operational design domain (ODD) of autonomous vehicles needs to be expanded on highways and urban roads in light of the substantial commercialization of Level 3 autonomous vehicles. Therefore, this study developed a specific infrastructure autonomous vehicle-based cooperative driving service to ensure the driving safety of autonomous vehicles on city roads. The traffic operation efficiency, safety evaluation, and core evaluation indices for each service were selected and analyzed to study the effect of each service. The result of the analysis confirmed that the traffic operation efficiency and safety of autonomous vehicles were improved through the V2X communication-based autonomous cooperative driving service. On the whole, the significance of this study is in deriving the effect of the autonomous cooperative driving service based on V2X communication on urban roads with interrupting traffic flow.

• Journal of Advanced Navigation Technology
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• v.27 no.5
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• pp.519-527
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• 2023

Air-launch means launching from aircraft such as fighter jets, and has various advantages, such as cost reduction and less environmental/weather impact during launch. However, there are no air-launch satellite in Korea. Examining air-based launch satellite and anti-satellite missiles operated and developed by foreign private companies and various countries confirmed the necessity of domestic research and development. In South Korea, various research activities, including satellite launch system design and development approaches for different launch platforms, have been carried out mainly by academia. Development of upward maneuver air launch technology which is launched in the air when the aircraft is moving upward is suggested. Additionally, an introduction to wind tunnel tests for safety separation verification is provided. A new concept for a test facility has been suggested to conduct drop tests.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.517-522
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• 2023

Existing radars have been developed by applying RF sub-array algorithms, and recently, fully digital Multiple-Input Multiple-Output (MIMO) radar algorithms have been implemented for vehicle radars. In this paper, the radar algorithm applying the Phased MIMO method to the hardware of the RF sub-array method, which is an unsecured technology, was implemented and verified in real time. In order to secure RF sub-array Phased MIMO algorithm technology, a hardware structure for FPGA-based real-time signal processing was presented, and performance was first predicted through design and simulation. Through this, the digital signal of FPGA-based broadband MIMO FMCW radar The processing hardware was developed, and the Phased MIMO radar algorithm of the RF sub-Array method was finally implemented and verified in real time. Based on this, it is judged that it will be possible to secure and apply core technologies necessary for terahertz band radar in the future.

• Transactions of Materials Processing
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• v.32 no.6
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• pp.311-320
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• 2023

Recently, lightweight of automotive parts has been required to solve environmental problems caused by global warming. Accordingly, research and development are proceeded on manufacturing of parts using aluminum that can replace steel for lightweight of the automotive parts. In addition, high strength aluminum can be applied to body parts in order to meet both requirements of lightening and improving crash safety of vehicle. In this study, hot blow forming of roof side rail is employed to manufacturing of the automotive parts with high strength aluminum tube. In hot blow forming, longer forming times and excessive thinning can be occurred as compared with conventional manufacturing processes. So optimization of process conditions is required to prevent excessive thinning and to uniformize thickness distribution with fast forming time. Mechanical properties of high strength aluminum are obtained from tensile test at high temperature. These properties are used for finite element(FE) analysis to investigate the effect of strain rate on thinning and thickness distribution. Variation of thickness was firstly investigated from the result of FE analysis according to tube diameter, where the shapes at cross section of roof side rail are compared with allowable dimensional tolerance. Effective tube diameter is determined when fracture and wrinkle are not occurred during hot blow forming. Also FE analysis with various pressure-time profiles is performed to investigate the their effects on thinning and thickness distribution which is quantitatively verified with thinning factor. As a results, optimal process conditions can be determined for the manufacturing of roof side rail using high strength aluminum.