• International Journal of Automotive Technology
• /
• 제3권1호
• /
• pp.41-46
• /
• 2002

Effect of secondary air injection (SAI) on hydrocarbon reduction has been investigated in a single cylinder Sl engine operating at cold-steady/cold-start conditions. The hydrocarbon emission and exhaust gas temperature with and without catalytic converter were compared with continuous and synchronized SAIs, which injected secondary air intermittently into exhaust port. Effects of SAI location, SAI pressure, SAI timing, and location of catalytic converter have been investigated and the results are compared for both SAls with base condition. At cold-steady condition, the rate of HC reduction increased as the location of SAI was closer to the exhaust valve for both synchronized and continuous SAls. The emission of HC decreased with increasing exhaust-A/F when it was rich, and was relatively insensitive when it was lean. The timing of SAI in synchronized SAI had significant effect on HC reduction and exhaust gas temperature and the synchronized SAI was found to be more effective in HC reduction and exhaust gas temperature compared to the continuous SAI . At cold-start condition, when the catalytic converter was located 20 cm downstream from the exhaust port exit, the catalytic converter warm-up period for both SAls decreased by about 50%, and the accumulated hydrocarbon emission during the first 120 s decreased about by 56% and 22% with the synchronized and continuous SAIs, respectively, compared to that of the base condition.

• 한국자동차공학회논문집
• /
• 제9권2호
• /
• pp.67-74
• /
• 2001

A synchronized secondaty air injection method has been developed to hydrocarbon emission by injecting secondary air intermittently into exhaust port. The method has been tested in a single cylinder spark-ignition engine operating at cold-steady / cold-start conditions. Effects of air injection timing, intake pressure and engine air-fuel ratio have been investigated at cold-steady condition. Also, hydrocarbon emission and exhaust gas temperature with catalytic conberter are compared with a continuous SAI method and base condition at cold-start condition. Resules show that hydrocarbon reduction rate and exhaust gas temperature are sensitive to the timing of synchronized SAI. At cold-steady condition, HC emission is minimum at engine air-fuel ratio of 10. At cold-start condition, the accumulated hydrocarbon emission during the first 120 s decreases about 56% and 22% with the synchronized and continuous SAI, respectively, compared to that of base condition.

• 로봇학회논문지
• /
• 제8권1호
• /
• pp.1-7
• /
• 2013

Body gesture Recognition has been one of the interested research field for Human-Robot Interaction(HRI). Most of the conventional body gesture recognition algorithms used Hidden Markov Model(HMM) for modeling gestures which have spatio-temporal variabilities. However, HMM-based algorithms have difficulties excluding meaningless gestures. Besides, it is necessary for conventional body gesture recognition algorithms to perform gesture segmentation first, then sends the extracted gesture to the HMM for gesture recognition. This separated system causes time delay between two continuing gestures to be recognized, and it makes the system inappropriate for continuous gesture recognition. To overcome these two limitations, this paper suggests primitive body model encoding, which performs spatio/temporal quantization of motions from human body model and encodes them into predefined primitive codes for each link of a body model, and Selective/Asynchronous Input-Parallel State machine(SAI-PSM) for multiple-simultaneous gesture recognition. The experimental results showed that the proposed gesture recognition system using primitive body model encoding and SAI-PSM can exclude meaningless gestures well from the continuous body model data, while performing multiple-simultaneous gesture recognition without losing recognition rates compared to the previous HMM-based work.

• 한국정보통신학회논문지
• /
• 제24권3호
• /
• pp.420-427
• /
• 2020

미·중 무역 분쟁이 시작된 이래로 전 세계의 관심은 물론이고 각 국의 무역에도 영향을 미치게 되었다. 하지만 미·중 무역전쟁은 전통산업의 경쟁에만 국한되지 않았으며 5G 산업의 경쟁도 갈수록 치열해지고 있다. 본 연구는 문헌연구를 중심으로 미국이 중국의 화웨이 회사에게 제재를 가하게 된 심층적인 원인을 분석하였다. 또한 이에 대한 문제점을 파악하고 해결방안을 제시하고자 한다. 미·중 무역 전쟁이 끊임없이 확대되고 빠르게 성장하고 있는 중국 산업은 미국의 산업에 영향을 줄 수 있으며 미국의 제재는 더 강화될 수 있다. 미국의 제재에도 불구하고 중국 5G의 빠른 속도와 효율적인 비용은 중국의 경쟁력을 더욱 높여 주고 있다. 하지만 앞으로 미국의 경제제재 하에서 중국의 5G 산업은 어떻게 생존하고 더욱 발전 할 것인가에 대한 심도 있는 연구가 이루어져야 한다.