• Environmental and Resource Economics Review
• /
• v.28 no.2
• /
• pp.307-326
• /
• 2019

The electric vehicle is a representative measure to reduce greenhouse gas and local air pollutants in the transportation sector. Most countries provide purchase subsidies and tax reductions to promote electric vehicle sales. The electric vehicles have been considered as zero-emission vehicles(ZEV) in light of the fact that there has been no pollutant emission during driving. However, recent studies have pointed out that the pollutant emitted from the process of generating electricity used for charging the electric vehicles need to be treated as emissions of the electric vehicles. Furthermore, the environmental benefits of electric vehicle replacing the internal combustion vehicle vary with the power mix. In line with the recent studies, this study analyzes the impact of electric vehicles based on the current power mix and future energy transition scenarios in Korea. To estimate the precise air pollutants emission profile, this study uses hourly electricity generation and TMS emission data for each power plant from 2015 to 2016. The estimation results show that the electric vehicles under the current power mix generate the environmental benefits of only -0.41~10.83 won/km. Also, we find that the environmental benefit of electric vehicle will significantly increase only when the ratio of the coal-fired power plant is reduced to a considerable extent.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.6
• /
• pp.887-894
• /
• 2018

An electric vehicle is emerging as an alternative to the response of global climate change and sustainability. However, an Electric vehicle has not been popular due to the constraints such as its price or technical limitations. In order to analyze the effect of purchasing electric vehicles, this study conducted a binary logistic regression model that demonstrates the relation between purchasing and influencing variables. Variables which have high correlation were excluded from the model through the correlation analysis to prevent multicollinearity. Socio-economic variables such as the number of owned vehicles, sex, ages are not significant. On the other hand, Variables related to prices, charging and policy are found to have a significant to effect on the purchase of electric vehicles. In accordance with the model estimated result, it seems to be necessary to improve the charging incentives, or to provide electric car information and to expand opportunities for experience electric vehicles. The result is also expected to be helpful for spreading electric vehicles and formulating policies.

• The Journal of the Korea Contents Association
• /
• v.21 no.4
• /
• pp.833-841
• /
• 2021

This study was an entertainer who was in charge of female music in the Joseon Dynasty, but the existence of gisaengs, who were recognized as'sexual partners' of the four grandfathers, and the Joseon Dynasty, when their existence was possible. I tried to reveal the social characteristics of Therefore, the research is meaningful in that it attempted to reveal the relationship between the grandfather and the gisaeng from various perspectives, and that it is possible to confirm the various social roles of the gisaeng. In the Confucian society, female musicians were not allowed to participate in Naeyeon and Chinjamrye, where women were the main pillars, so not only could the girl's music survive until the end of the Joseon Dynasty, but it was enough to reveal the existence of a professional artist. The existence of gisaengs is not irrelevant to the social background of the Joseon Dynasty, and therefore, it is impossible to define the Joseon Dynasty with the holy morality of modern society. It is believed that 『catching green onions is expected to enhance the aspect of a gisaeng as a celebrity, based on the interpretation that it is viewed from the perspective of an entertainer possessing an extraordinary and noble spirit rather than portraying the gisaeng in an erotic standard.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.23 no.1
• /
• pp.25-36
• /
• 2021

Hydrogen in hydrogen-electric vehicles has a wide range of combustion and explosion ranges, and is a combustible gas with a very fast flame propagation speed, so it has the risk of leakage, diffusion, ignition, and explosion. The fuel tank has a Thermally active Pressure Relief Device (TPRD) to reduce the risk of explosion and other explosions, and in the event of an accident, hydrogen inside the tank is released outside before an explosion or fire occurs. However, if an accident occurs in a semi-closed space such as an underground parking lot, the flow of air flow is smaller than the open space, which can cause the concentration of hydrogen gas emitted from the TPRD to accumulate above the explosion limit. Therefore, in this study, the leakage rate and concentration of hydrogen over time were analyzed according to the diameter of the nozzle of the TPRD. The diameter of the nozzle was considered to be 1 mm, 2.5 mm and 5 mm, and ccording to the diameter of the nozzle, the concentration of hydrogen in the underground parking lot increases in a faster time with the diameter of the nozzle, and the maximum value is also analyzed to be larger with the diameter of the nozzle. In underground parking lots where air currents are stagnant, hydrogen concentrations above LFL (Lowe Flammability Limit) were analyzed to be distributed around the nozzle, and it was analyzed that they did not exceed UFL (Upper Flammability Limit).

• Journal of the Institute of Convergence Signal Processing
• /
• v.23 no.1
• /
• pp.21-27
• /
• 2022

Traditional automobile or 2-wheeled robot have limitations on mobility because of their mechanical structure. As traditional automobile is being replaced by electric cars, robot technology is applied to the car industry. In robotics, many researchers worked on omnidirectional mobile robot and produced lots of noticeable results. However in many of the results, specialized wheels such as Mecanum wheels are required. That imposes restrictions on robot speed and outdoor driving. We proposed a 2-wheeled modular robot that has omnidirectional mobility without using specialized wheels. In this paper, we propose a 4-wheeled omnidirectional mobile robot that consists of those two modular robots. The proposed robot adopts electric brakes to combine wheel housings and the robot body or to separate wheel housings from the robot body. Two absolute-type encoders and four incremental encoders are used to control the position of the wheel housing and velocities of the wheels. The proposed robot has omnidirectional mobility and can move fast and outdoor with normal tire wheels. We implemented the proposed robot and the feasibility and stability of the robot is verified by two separate experiments.

• Smart Media Journal
• /
• v.11 no.5
• /
• pp.75-81
• /
• 2022

In order to respond to carbon neutrality and climate change in agriculture, agricultural machinery, which has been developed centered on internal combustion engines, needs to be converted to an electric-based technology that does not emit greenhouse gases. In this study, simulations for electric UTV suspension design were performed to reduce vibration and shock of electric UTV for agricultural use and to improve driving stability and control performance of the vehicle. The simulation was performed by dividing the tolerance load of the vehicle body and the loaded load state. The range of motion of the suspension spring of UTV is within 30% of the range of motion under condition B under tolerance, the displacement of the UTV suspension with full load is reduced from 264mm to 121mm, and the damping speed is 260mm/s to 300mm/s that it can be seen that the range of motion is within 60%. Suspension design of electric UTV for multi-purpose agricultural work is a very important factor for maintaining agricultural work ability in towing work such as tillage as well as driving and terrain adaptation. The results of this study can be usefully used to determine the spring parameters with the appropriate damping range so that the electric UTV can be used for various agricultural tasks.

• The Journal of the Korea Contents Association
• /
• v.22 no.9
• /
• pp.85-94
• /
• 2022

In modern society, environmental and energy problems have caused to replace cars with environment friendly energy. Vehicles with internal combustion engine which use petroleum are one of the factors that influence global pollution due to environment problems such as fine dust and ozone layer destruction. In addition use of energies for automobile making resources to become depleted. To solve this limited oil energy problem by using other energy sources. To the problem using electric energy and green energy as alternative for a solution. Among environment friendly energies this paper studies the possibility of drive service for autonomous vehicles that self-charges using only solar energy and whether they can be used as pollution free and alternative energy for automobiles. Studies was researched based on published literature review, data from ministry of transportation and automobile companies. Also case of electric vehicle and prototype automobile using only solar energy and the theory of near future technologies. Many automakers are using electric cars as alternative energy. Also making efforts to use solar energy as an substitute energy source and as a way to supplement electricity. Results show that there is a potential on operating autonomous vehicle using only solar energy. Furthermore, it will be possible to use automobiles actively, also use and supply solar energy. This paper suggest the possibility of contributing to the future of the automotive industry.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.23 no.6
• /
• pp.605-612
• /
• 2021

Amid growing global damage due to abnormal weather caused by global warming, the introduction of eco-friendly cars is accelerating to reduce greenhouse gas emissions from internal combustion engines. Accordingly, many studies are being conducted in each country to prepare for the explosion of hydrogen fuel in semi-closed spaces such as tunnels and underground parking lots to ensure the safety of hydrogen-electric vehicles. As a result of predicting the explosion pressure of the hydrogen tank using the equivalent TNT model, it was found to be about 1.12 times and 2.30 times higher at a height of 1.5 meters, respectively, based on the case of 52 liters of hydrogen capacity. A review of the impact on the human body and buildings by converting the predicted maximum explosive pressure into the amount of impact predicted that all predicted values would result in lung damage or severe partial destruction. The predicted degree of damage was applied only by converting the amount of impact caused by the explosion, and considering the additional damage caused by the explosion, it is believed that the actual damage will increase further and safety and disaster prevention measures should be taken.

• Journal of Digital Convergence
• /
• v.20 no.5
• /
• pp.463-476
• /
• 2022

After industrialization in the past, the automobile industry has continued to grow centered on internal combustion engines, but is facing a major change with the recent 4th industrial revolution. Most companies are preparing for the transition to electric vehicles and autonomous driving. Therefore, in this study, topic modeling was performed based on LDA algorithm by collecting 4,002 domestic papers and 68,372 overseas papers that contain keywords related to CASE (Connectivity, Autonomous, Sharing, Electrification), which represent future automobile trends. As a result of the analysis, it was found that domestic research mainly focuses on macroscopic aspects such as traffic infrastructure, urban traffic efficiency, and traffic policy. Through this, the government's technical support for MaaS (Mobility-as-a-Service) is required in the domestic shared car sector, and the need for data opening by means of transportation was presented. It is judged that these analysis results can be used as basic data for the future automobile industry.

• Journal of the Korean Arthroscopy Society
• /
• v.9 no.2
• /
• pp.222-231
• /
• 2005

Purpose: This article describes a double-bundle ACL reconstruction technique using a five-strand hamstring tendon autograft with conventional anteromedial bundle reconstruction and additional posterolateral bundle reconstruction. Operative technique: For the tibial tunnel, the conventional single tunnel technique is performed and for the femoral tunnel, the double tunnel technique is performed with the anteromedial and posterolateral bundle. After minimal notchplasty, the anteromedial femoral tunnel is prepared with leaving one milimeter of posterior femoral cortex within the over-the-top, which if positioned at the 11-o'clock orientation for the right knee or at the 1-o'clock position for the left knee. The posterolateral femoral tunnel that is located 5 to 7 mm superior to the inner margin of the lateral meniscus anterior horn at $90^{\circ}$ of flexion is prepared with tile outside-in technique using a 4.5 cannulated reamer. The graft material for the double bundle reconstruction is made of the conventional four-strand hamstring autograft in the anteromedial bundle and of a single-strand semitendinosus tendon in the posterolateral bundle. The anteromedial bundle is fixed with using a rigid fix system on the femoral side and the posterolateral bundle is fixed to tie with the miniplate from the outside femur. Then, with the knee in $10^{\circ}\;to\;20^{\circ}$ of flexion, a bioabsorbable screw is simultaneously applied to achieve tibial fixation with tensioning of both bundles. Conclusion: A double bundle reconstruction with five-strand hamstring autograft, which is designed with a favorable conventional anteromedial bundle and an additional posterolateral bundle to restore rotation stability, seems to be a very effective method for the treatment for ACL instabilities.