• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.111-122
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• 2018

At present, the ground transportation system is saturated in many countries including Korea. To overcome this problem, many researches of developing a roadable personal air vehicle (PAV) are being carried out to alleviate traffic congestion and to accomplish door-to-door mobility through three-dimensional traffic system. In this study, the thrust-to-weight ratio, the wing loading, and the power-to-weight ratio that are major design parameters for the sizing of roadable PAVs were calculated under the constraints of ground roll, climb rate, maximum cruise speed, service ceiling, stall speed. Also, in the sizing process, the study was conducted to determine the design point using the graphs of thrust-to-weight ratio, wing loading, power-to-weight ratio, and brake horse power for the mission profiles considering domestic environments and the FAR PART 23 which is the GA class aircraft certification standard.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.28-33
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• 2020

In this study the possibility of hydrogen as a fuel in a small-sized two-stroke SI (Spark ignition) engine was investigated. For this purpose, experimental setup including an engine, a dynamometer, equipments for hydrogen and lubricant oil supply was prepared. And then preliminary experiments for the hydrogen-fueled engine combustion were conducted. In the case of hydrogen-fueled engines comparing to gasoline backfire occurs when the excess air ratio is lower than a specific value. This can cause engine power reduction and damage to the engine parts. The engine was controlled to operate at lean conditions to prevent backfire. Through the control of excess air ratio, the maximum engine brake power output of 3 kW was achieved in a 210 cc engine, while it was 6 kW in case of gasoline fuel.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.146-159
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• 2021

vehicle simulator as part of an empirical analysis the driving characteristics of elderly drivers. To this end, the driving characteristics of the elderly driver from previous study review. he driving characteristics of the elderly the driving elderly driver and general driverIn summarizing these experimental results, the -test showed different driving characteristics from general drivers in all items except for one side of the lane, such as driving speed and driving operation (brake, throttle, steering operation) at a significance level of 95%. Second, when changing lanes, it was difficult for elderly driver to maintain speed and secure an appropriate distance between carslderly driver changed lanes even in inappropriate situations (short distances between cars). Third, in unexpected situation, elderly drivers needed more distance and time.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.715-727
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• 2021

This research is to investigate the concept of Local Housing Association, and stepwise implementation procedure, through the theoretical consideration, and then to find out overall problems happening in the process of pushing ahead with Local Housing Association, including problems in the corresponding business stage, based on the cases of Local Housing Association that have been appearing in Changwon areas, Gyeongnam, and to present legal and policy directions for solutions to it, based on it. First, regarding improvement measures at the stage of promotion committee, it is necessary to introduce the system to report the establishment of promotion committee to cities, provinces, and districts under the jurisdiction of the location of overall business, for the establishment of association. In order to secure the professionalism of promotion committee, it is necessary to enforce those members to receive education and training for a certain period, and improve the system to post on Website or through public notices. Second, regarding improvement measures at the stage of the approval of establishment, Local Housing Association have difficulties in replacing members and joining new memberships, after getting the approval of the establishment, which can put the brake on business operation. Finally, in order to prevent crime actions, such as embezzlement or breach of duty, in advance, it is necessary to establish the institutional system that allows every member to check details of business fund. It is expected that this research would minimize side effects incurred by Local Housing Association System and help Local Housing Association take full institutional responsibility and play an axis of housing supply policy.

• Journal of the Society of Disaster Information
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• v.17 no.2
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• pp.319-328
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• 2021

Purpose: Recently, a large social disaster has called for the need to diagnose social disaster safety, and the Ministry of Public Administration and Security calculates and publishes regional safety ratings such as regional safety index and national safety diagnosis every year. The existing safety diagnosis system uses equal intervals or normal distribution to grade risk maps in a uniform manner. Method: However, the equidistant technique can objectively analyze risk ratings, but there is a limit to classifying risk ratings when the distribution is skewed to one side, and the z-score technique has a problem of losing credibility if the population does not follow a normal distribution. Because the distribution of statistical data varies from indicator to indicator, the most appropriate rating should be applied for each data distribution. Result: Therefore, in this paper, we analyze the data of disaster indicators and present a comparison and suitable method for traditional equidistant and natural brake techniques to proceed with optimized grading for each indicator. Conclusion: As a result, three of the six new indicators were applied differently from conventional grading techniques

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.11
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• pp.36-42
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• 2021

This study was conducted to analyze the effect of the gear specification and gear quality corresponding to the macro geometry on the gear transmission error. The two pairs of gears with large and small transmission errors were selected for calculation, and two pairs of gears were manufactured with different gear quality. The test gears were manufactured by two different gear specifications with ISO 5 and 8 gear quality, respectively. The transmission error measurement system consists of an input motor, reducer, encoders, gearbox, torque meter, and powder brake. To confirm the repeatability of the test results, repeatability was confirmed by performing three repetitions under all conditions, and the average value was used to compare the transmission error results. The transmission errors of the gears were analyzed and compared with the test results. When the gear quality was high, the transmission error was generally low depending on the load, and the load at which the decreasing transmission error phenomenon was completed was also lower. Even when the design transmission error according to the gear specification was different, the difference of the minimum transmission error was not large. The transmission error at the load larger than the minimum transmission error load increased to a slope similar to the slope of the analysis result.

• 재활복지
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• v.16 no.3
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• pp.421-437
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• 2012

The goal of this study is to provide the basic information for improvement of domestic standards on the powered scooter and the electric wheelchair considering using environments in the nation. The international standards and domestic standards have been analyzed and compared, in order to propose improved domestic standards. Based on the research, the items and standards for general and functional recommendations, electric features, and other suggestions have been reexamined so that the improvements on test item and standards have been identified, corrected, and summarized including max. speed, brake system, lights and so on. We have been preparing the reference data for the improvement of standards on the powered scooter and the electric wheelchair through the comparison & analysis on the international and domestic standards.

• Journal of Urban Science
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• v.11 no.2
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• pp.45-54
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• 2022

Recently, regulations on automobile exhaust gas emission are being strengthened. Accordingly, automobile exhaust gas emissions are expected to decrease and continue to decrease. On the other hand, many countries do not yet consider the emission of non-exhaust air pollutants from automobiles as important. Automobile non-exhaust substances are classified into three categories: tire dust emissions, brake wear emissions, and road scattering dust. In particular, in the case of tire dust, research results exist that pollutant emissions increase as the weight of a vehicle increases. Since the weight of trucks varies according to the load and the load along the axles is also different, it can be expected that the emission of PM10 from the tire dust will be different depending on the loading method. Therefore, this study was conducted on the amount of PM10 generated in tire dust considering the axle load of the truck according to the loading method. However, it was confirmed that the total amount of PM10 was less than that all loads are loaded in the front or rear when the load was evenly distributed in the front and rear of the cargo compartment. In particular, if the load is distributed evenly in the front and back of the cargo compartment and the load in the front part is divided into 2 to 6 and loaded, as the number of divided loading increases the amount of PM10 generated decreases. And when the load is divided into 6 pieces, the total amount of PM10 generated is 0.3952g, the minimum value. If the load is divided into 6 or more and loaded evenly, the total PM10 generated continuously increases and converges to about 0.3964g.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.3
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• pp.361-370
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• 2017

In this paper, correlation analysis was performed between questionnaire and machine learning based aggressive tendency measurements. this study is part of a aggressive driver detection using machine learning and questionnaire. To collect two types tendency from questionnaire and measurements system, we constructed experiments environments and acquired the data from 30 drivers. In experiment, the machine learning based aggressive tendency measurements system was designed using a driver behavior detection model. And the model was constructed using accelerate and brake position data and hidden markov model method through supervised learning. We performed a correlation analysis between two types tendency using Pearson method. The result was represented to high correlation. The results will be utilize for fusing questionnaire and machine learning. Furthermore, It is verified that the machine learning based aggressive tendency is unique to each driver. The aggressive tendency of driver will be utilized as measurements for advanced driver assistance system such as attention assist, driver identification and anti-theft system.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.1188-1191
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• 2021

The function of the black box can be combined with a car to check the video through a cloud server, reduce the hassle of checking the video through a memory card, check the black box image in real time through a PC and smartphone, and check the user's Excel, brake operation status, and handle control record at the time of the accident. In addition, the goal was to accurately identify vehicle accidents and simplify accident handling through artificial intelligence object recognition of black box images using cloud services. Measures can be prepared to preserve images even if the black box itself loses, such as fire, flooding, or damage that occurs in an accident. It has been confirmed that the exact situation before and after the accident can be grasped immediately by providing object recognition and log recording functions under actual driving experimental conditions.