• 한국공작기계학회논문집
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• 제13권1호
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• pp.100-106
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• 2004

All vehicles need the good quality of riding. Especially shifting shock is very important in the evaluation of the riding. Shifting shock is caused by transmission operation that one part and other part of gem are contacting together. This shock affect the feeling of driving. It is clear from these results that the shifting shock is affected by clutch pressure, pressure mode, inertia etc.

• 한국멀티미디어학회논문지
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• 제25권9호
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• pp.1266-1272
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• 2022

With the recent development of computer vision technology, image processing-based mechanical devices are being developed to realize autonomous driving. The camera-taken images of image processing-based machines are invisible due to scattering and absorption of light in foggy conditions. This lowers the object recognition rate and causes malfunction. The safety of the technology is very important because the malfunction of autonomous driving leads to human casualties. In order to increase the stability of the technology, it is necessary to apply an efficient haze removal algorithm to the camera. In the conventional haze removal method, since the haze removal operation is performed regardless of the haze concentration of the input image, excessive haze is removed and the quality of the resulting image is deteriorated. In this paper, we propose an automatic haze removal method that removes haze according to the haze density of the input image by applying Ngo's Haziness Degree Evaluator (HDE) to Kim's haze removal algorithm using Hazy Particle Map. The proposed haze removal method removes the haze according to the haze concentration of the input image, thereby preventing the quality degradation of the input image that does not require haze removal and solving the problem of excessive haze removal. The superiority of the proposed haze removal method is verified through qualitative and quantitative evaluation.

• 공업화학
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• 제25권6호
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• pp.639-644
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• 2014

국내 자동차사는 순정엔진오일을 정해놓고 일반엔진오일보다 높은 가격으로 판매하고 있다. 본 연구에서는 국내 순정엔진오일 14종과 동급의 일반엔진오일(KS제품) 14종에 대하여 품질비교 및 차량을 이용하여 10,000 km씩 주행한 뒤, 회수된 엔진오일의 물성을 분석하였다. 분석 결과, 사용하지 않은 신유는 순정엔진오일과 일반 엔진오일의 품질이 대동소이하였지만, 오히려 주행 후 회수된 일반엔진오일은 순정엔진오일에 비해 윤활성이 우수하였으며, 동점도와 전산가 변화가 작은 것으로 나타났다.

• 한국군사과학기술학회지
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• 제18권1호
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• pp.8-14
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• 2015

Transmission of a tracked vehicle designed for multiple functions such as steering, gear-shifting, and braking is a core component of heavy vehicle to which the power is transferred based on combined technology of various gears, bearing, and fluid machineries. Robustness and durability of transmission, however, have been issued due to a large number of driving units and sub-components inside its body. Particularly, transmission housing is important structure which supports the transmission, and is made of aluminum alloy. Thus, structural robustness against such mechanical loading or vibration must be attained. Structural reliability evaluation through FEM analysis can save time and cost of the actual tests. In this study, structural evaluation is conducted on output housing of transmission, which is core component of tracked vehicle, using the simulation program. In addition, transmission dynamo test is performed to evaluate structural robustness of the output housing against the vibration which can be produced during the transmission operation.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.161-167
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• 2021

Nowadays, small- and medium-sized enterprises (SMEs) are placed among the key components of the economy in both developed and developing countries. They are internationally known as the driving force based on their enormous contributions to Gross Domestic Product (GDP) and generating new employment. They are generally presumed as the leader of environmental sustainability, economic prosperity, and innovation, particularly for the economy of developing countries such as Vietnam. However, SMEs have difficulty in raising capital, as well as access to credit. One of the reasons is that there are inadequacies in accounting information quality in SMEs as well as the provision of accounting information and accounting information confidentiality. The main objective of this study was to identify, evaluate, and measure the attributes of accounting information quality of SMEs in Hanoi. The study was based on a field survey using a semi-structured questionnaire on a sample of 150 accountants. The study has identified and measured six (6) attributes of accounting information quality of SMEs that have great effects on accountants. There is, statistically, no significant difference in the level of accounting information quality of SMEs in Hanoi from these different business areas. There is no, statistically, significant difference in the level of accounting information quality of SMEs in Hanoi between the mentioned three groups of the job description. Based on the findings, some recommendations are given for SMEs to improve accounting information quality.

• 한국ITS학회 논문지
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• 제21권5호
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• pp.103-116
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• 2022

국토교통부는 원활한 자율주행자동차 서비스 확대를 위해 총 7개 지역을 자율주행자동차 시범운행지구로 지정·고시하여 매년 운영성과에 대한 평가를 받도록 하였다. 본 연구는 이를 위한 기초연구로서 자율주행자동차 서비스의 정성적 만족도를 설문조사 기반으로 평가하였다. 첫째, 세종시 자율주행 서비스 이용자와 일반인을 대상으로 자율주행 서비스 인식에 대한 설문조사를 실시하였다. 그 결과, 자율주행 서비스 이용자가 자율주행 기술에 대한 단계 인지, 이용 의향 등이 일반인에 비해 높게 나타났다. 둘째, 수요대응형 대중교통 서비스 이용자와 세종시 자율주행 서비스 이용자를 대상으로 서비스 만족도 설문조사를 실시하였다. 비모수통계분석 방법 중 윌콕슨 순위합 검정(Wilcoxon Rank Sum Test)을 통한 분석 결과, 자율주행 서비스 이용자의 경우 안전과 관련된 요인들이 전반적인 만족도에 영향을 미치는 것으로 나타났다. 반면, 수요대응형 대중교통 서비스 이용자들은 서비스 편의성과 관련된 항목들이 전반적인 만족도에 영향을 미치는 것으로 나타났다. 이러한 설문조사 결과는 향후 자율주행 서비스의 개선사항 및 정책수립에 대한 기초자료로 활용이 기대된다.

• 에너지공학
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• 제23권2호
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• pp.28-34
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• 2014

자동변속기유는 자동차의 자동변속기의 성능을 유지시키기 위해 사용되는 유체이다. 최근 자동차 제조사에서는 일반적으로 자동변속기유를 80000~100000 km 주행후 교환 또는 무교환을 보증하고 있지만 국내에서는 많은 운전자들이 50000 km 이하에서도 자동변속기유를 교환하고 있는 것으로 조사되었다. 빈번한 자동변속기유의 교환은 환경오염과 차량유지비용을 상승시키는 원인으로 작용되고 있다. 본 연구에서는 사용하지 않은 신유와 50000 km와 100000 km를 각각 주행한 뒤 회수된 자동변속기유를 대상으로 인화점, 연소점, 유동점, 동점도, 저온겉보기점도, 전산가, 금속분과 같은 물리적 특성을 분석하였다. 연구결과, 신유에 비해 사용유는 전산가, 유동점, 금속분이 증가되는 것을 확인하였지만, 두 종류의 사용유(50000 km, 100000 km)의 물리적 특성과 금속분 함량의 차이는 크지 않음을 알수 있었다.

• Journal of Biosystems Engineering
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• 제23권5호
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• pp.445-456
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• 1998

This study was carried out to evaluate the performance of a medium scale rice polisher of 2.5 t/h and to improve its performance for producing the clean rice with high quality. The maximum internal pressure, broken rice ratio. whiteness in the rice polisher were investigated, and the effects of outlet resistance, water spraying rate, shaft revolution speed and rice moisture content on the polishing performance were analyzed to find out proper operating conditions. The conclusions of this study were as follows: 1. In the performance evaluation of the polisher, the broken rice ratio increment of 0.1%, the max. internal pressure of about 11 N/${cm}^2$, and whiteness increment of 2.2~3.7 resulted at the conditions of 20 PS driving power, 950 rpm, 150 cc/min water spraying rate, 44.1 Nㆍcm outlet resistance and about 15% rice moisture content. 2. Though max. internal pressure and whiteness at the 17% rice moisture content were higher than those at the 15% moisture content under the same operating conditions of the polisher, but the broken rice rate at the 17% moisture content was absolutely low compared with that at 15% moisture content. The water spraying effect to reduce broken rice and to increase whiteness was much significant at the 15% moisture content not significant at 17% moisture content. 3. The main parameter of the performance was outlet resistance, and low resistance of about 44.1 Nㆍcm was recommended at the polisher. 4. The proper water spraying rate in the polisher was about 150 cc/min. 5. As the shaft revolution speed decreased from 950 rpm and 800 rpm to 650 rpm, the broken rice ratio increased and whiteness decreased. 6. As the driving power of the polisher increased from 20 PS to 30 PS, the max. internal pressure decreased by about 1~2.5 N/${cm}^2$ and whiteness increased by about 1~2, but the broken rice rate was not changed. 7. The proper operating conditions of the polisher seemed to be the revolution speed of 800-950 rpm, the water spraying rate of about 150 cc/min, the oulet resistance of about 44.1 N.cm and 30 PS driving power.

• 한국도로학회논문집
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• 제19권5호
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• pp.97-106
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• 2017

PURPOSES: This study aims to evaluate the effects of vehicle dynamic behaviors on ride quality. METHODS : Simulation and field test were conducted to analyze the behavior of a driving vehicle. The simulation program CarSIM was applied and an INS (Inertial Navigation System) was used for field experiments. A small simulator was developed to simulate vehicle behavior such as roll, pitch, and bounce. The panels evaluated the ride quality in five stages from "very satisfied"to "very dissatisfied."Experiments were conducted on a total of 144 cases of vehicle behavior combinations. RESULTS :In both simulation and field tests, pitch is the largest and yaw the smallest. Especially in the field test, the amount of yaw is very low, about 7% of pitch and 18% of roll. The sensitive and extensive analysis conducted related ride quality with changing the frequency and amplitude. It was found that the most sensitive frequency range is 8 Hz across all amplitudes. Moreover, the combination of the roll and bounce was most sensitive to the ride quality at the low-frequency range. CONCLUSIONS : This result show that the vertical vehicle behavior (bounce) as well as the rotational behavior (roll and pitch) are highly correlated with ride quality. Therefore, it is expected that a more reasonable roughness index can be developed through a combination of vertical and rotational vehicle behavior.

• 한국환경과학회지
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• 제7권5호
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• pp.573-580
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• 1998

This study examined the carbon dioxide ($CO_2$) pollution inside vehicles under low ventilation condition and evaluated the Air Quality System (AQS) for in-vehicle air quality using two techniques. The low ventilation condition is not recommended in order to keep oxygen-rich condition inside vehicles. Under the low ventilation condition, the in-vehicle $CO_2$ concentrations exceeded 1,000 ppm, the air qualify guidelines in the United States, Western Europe, and Japan, indicating more oxygen deficiency inside vehicles. On the contrary, with the AQS-on condition, the in-vehicle $CO_2$ concentrations were less than 1,000 ppm fer most of the driving time, indicating that the AQS could solve the problem of $CO_2$ accumulation inside vehicles under the low ventilation condition. The AQS test conducted by comparing carbon monoxide (CO) and volatile organic compound (VOC) concentrations inside two vehicles indicated that the AQS effectively decreased the in-vehicle concentrations by 21 to 36%, as compared to medium ventilation condition with the windows closed, the vent opened, and air conditioning on. In addition, The AQS test conducted by comparing the interior and exterior concentrations indicated that the AQS effectively decreased the in-vehicle concentrations by 18 to 31%, as compared to medium ventilation condition.