• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.49-58
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• 1997

In this paper, a transfer function was obtained for a PWM high speed solenoid valve controlled metal belt CVT system. The transfer function was defined as the ratio of speed ratio to PWM duty ratio and derived in time domain by linear regression analysis from the experimental results. The transfer function obtained showed different dynamic characteristics for the up and down shift. Also, LQG/LTR controller was designed for the CVT system using the transfer function. It is seen from the experimental results that LQG/LTR control showed good performance for the speed ratio tracking and disturbance rejection. The phase difference and relatively slow response are considered due to the inaccuracy os the transfer functions, which resulted from the inherent nonlinearities of the transmission characteristics of the metal belt CVT.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.322-330
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• 2010

초고층 건축물의 급속한 증가는 건축물 화재 시 고층에서 보다 빨리 피난할 수 있는 구조적 피난설비를 요구한다. 기존의 구조용 완강기나 구조대는 고층에서는 피난자의 공포감을 충분히 해소하기에 역 부족이었다. 이러한 문제점을 보완한 성능을 갖추어 동시에 다수의 피난자를 대피시킬 수 있는 새로운 피난기구가 요구되고 있다. 이에 고층에서도 동시에 여러 사람이 안전하고, 신속하게 피난층까지 무사히 대피가 가능한 유압식 피난기구를 고안하고, 개략 설계하게 되었다. 이 연구를 기초로 향후 상세설계를 마친 후 고층 건축물에 적용되어 안전한 피난기구가 되었으면 한다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.7-14
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• 2015

The aim of this research is suggesting dry processed bottom ash as a new and economical source of lightweight aggregate for mortar and concrete. The dry process of bottom ash is an advance method of water-free and no chloride because only cooled down by double dry conveyer belt systems. Furthermore, because of relatively slow cooling down process helps burning up the remaining carbon in bottom ash. Using this dry process bottom ash, to evaluate the feasibility of using as a lightweight aggregate for mortar and concrete, two-phase of experiments were conducted: 1) improving shape of the bottom ash, and 2) controlling grade of the bottom ash. From the first phase of experiment, additional abrasing process was conducted for round shape bottom ash, hence improved workability and compressive strength was achieved while unit weight was increased comparatively. Based on the better shape of bottom ash, from the second phase, various grades were adopted on cement mortar, standard grade showed the most favorable results on fresh and hardened properties. It is considered that the results of this research contribute on widening sustainable method of using bottom ash based on the dry process and increasing value of bottom ash as a lightweight aggregate for concrete.