• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.523-526
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• 2014

Recently, all the generators needed of the boats are being imported, so our objective is to make a national production of soundproof generators. We have already built a marine soundproof generator and it has also been hrough an endurance test for its commercialization. This paper has the noise vibration measurements needed for maintaining its durability and performance. We concluded that the difference of the noise values with and without the case was of 11.4dB.

• Journal of Biosystems Engineering
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• v.28 no.4
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• pp.285-294
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• 2003

This study was carried out to propose a new-concept internal combustion engine which has great potential advantages to the conventional engines. Proposed new-concept engine is a kind of rotary engine. A rotor is rotating concentrically in a cylinder which is divided into two partitioning valves, and it makes four compartments in the cylinder. The volumes of each of four compartments are changing continuously with the rotor movement and performs the functions of intake, compression. expansion and exhaust simultaneously. Expected thermal efficiency for the real cycle is 26 percent at conditions of 1,000 rpm and compression ratio of 8.0, which is 3 to 4 percent higher than that of the conventional engines such as the piston engine, gas turbine and Wankel rotary engine. A simulation procedure proved that the new concept engine is functional, and has many potential advantages compared to the existing conventional engines.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.97-106
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• 2011

Both an optimal design of the engine operating strategy and fuel economy prediction technique for a HEV under the vehicle driving condition are very crucial for the development of vehicle fuel economy performance. Thus, in this study, engine operating characteristics of PRIUS III were analyzed with vehicle running conditions and the correlations between vehicle tractive power and fuel consumption were introduced. As a result, fuel economy performance of PRIUS III with various test modes were predicted and verified. Errors of predicted fuel economy were between -5% and -1%.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.343-346
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• 2012

추천 엔진의 지속적인 성능 향상을 위해서는 객관적 성능 평가가 이루어져야 하지만, 콘텐츠 추천 기술은 평가 데이터 구축이 어렵고 평가를 위한 심도 깊은 연구가 이루어지지 못하여 많은 어려움을 가지고 있다. 본 논문은 콘텐츠 추천 시스템의 객관적인 평가를 시스템 구축에 대한 연구이다. 추천 알고리즘의 효율적이고 객관적인 성능 평가를 위하여 기존 연구들을 분석하여 대표적인 성능평가 양식들을 구현하였다. 통계적인 평가를 위한 사용자 데이터를 수집하였으며 데이터 크기, 평가방식, 추천 알고리즘의 모듈 별 성능 추이를 쉽게 변경하고 관찰할 수 있도록 인터페이스를 설계하였다. 이러한 평가 시스템의 도입으로 콘텐츠 추천 알고리즘의 지속적인 성능 보완을 기대 할 수 있을 것이다.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.437-441
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• 2006

본 논문에서는 RFID 위치추적엔진과 지능형 에이전트를 이용한 선호상품 추천 기법을 이용하여 RFID기반 위치추적을 이용한 실시간 선호 상품 추천 시스템을 제안한다. 매장안에서 RFID 태그가 부착된 스마트 카트를 이용하여 고객의 위치를 실시간으로 파악하여 각 구역별 쇼핑시간과 개별 고객의 구매 히스토리 분석 및 이동 구역 예측을 통해 실시간으로 쇼핑 매장에서 각 고객의 선호상품을 추천한다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.153-155
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• 2011

최근 음악 검색 연구에서 일반적으로 사용되는 방법은 키워드 중심의 텍스트 기반 검색방식, 음원의 특징 정보나 허밍 질의 처리 등을 이용하는 내용기반 검색 방식 등이 있다. 그러나 이러한 검색 방식은 단순히 원하는 음악을 질의에 따라 검색해 주며 인간의 감성을 고려하지 못하고 있다. 따라서 본 논문에서는 질의에 의한 검색뿐만 아니라 질의한 음원과 감성정도가 같은 음원을 추천하는 인간 감성 기반 음악 검색 및 추천 시스템을 제안한다. 인간 감성 기반 음악 검색 및 추천 시스템은 크게 2가지 요소로 구성된다. 첫 번째는 사용자가 질의한 질의어를 분석하는 감성기반 검색추론엔진과 두 번째는 음원의 특징 정보 및 감성 정보를 가지고 있는 음원 감성 정보 데이터베이스로 구성된다. 사용자의 감성에 따라 음악을 검색하고 추천한다는 것은 향후 음반 산업에 큰 발전에 기여할 것으로 기대한다.

• Journal of ILASS-Korea
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• v.15 no.1
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• pp.25-30
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• 2010

The capability of pilot injection with small fuel quantity at all engine operating conditions is one of the main feature of the common rail direct injection system. The purpose of the pilot injection is to lower the engine noise and to reduce the NOx emissions. This study describes the pilot spray structure characteristics of the common-rail diesel injectors with different electric driving characteristics, including solenoid-driven and piezo-driven type. Namely three common-rail injectors with different electric current wave were investigated in this study. The pilot spray characteristics such as spray speed, spray tip penetration, and spray angle were obtained by spray images, which is measured by the back diffusion light illumination method with optical system for high-speed temporal photography. As this research results, it was found that pilot injection of common-rail system was effected by rate of injection with different electrical characteristic for driving the injector.

• Journal of ILASS-Korea
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• v.15 no.1
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• pp.8-16
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• 2010

This paper present the diesel spray characteristics at different injection system parameters in a HSDI diesel engine. The spray characteristics was calculated by the coupled simulation of fuel injection system model and three-dimensional KIVA-3V code with TAB spray model. The relevant injection parameters are accumulator volume, control chamber initial volume, control orifice diameter, needle valve diameter and nozzle chamber initial volume, etc. Parametric investigation with respect to twelve relevant injection parameters showed that there was a significant advantage in varying control chamber initial volume, control chamber orifice diameter, and nozzle chamber orifice diameter with respect to effect the SMD and fuel injection speed. Consequently, in order to design the fuel injection system for spray characteristics, it seems reasonable to suppose to be optimized the fuel injection system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.3045-3054
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• 1993

The mechanics related with piston-slap induced vibration has been studied in terms of non-dimensionalized dynamic equation of motion, various non-dimensional parameters such as non-dimensional side-thrust force and non-dimensional impact velocity throughout the numerical simulation. Experimental verification on the suggested prediction method has been also performed by using single cylinder engine which was carefully designed and manufactured to wisely control the engine parameters, especially clearance and the mass of piston. The predicted and experimentally observed vibration signature confirm that the proposed method is practically useful.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.96-102
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• 2004

The diesel particulate filter(DPF) is effective for particulate removal from diesel engine under a variety of conditions, and then the regeneration strategies is very important in the aspects of engine fuel consumption and engine durability. This paper addresses the changes of Peugeot 406 vehicle engine parameters(fuel injection timing, period, rail pressure, emissions exhaust temperature so on) during DPF regeneration. additionally, checked the soot loading mass with mileage and the change of fuel consumption and performance with ash accumulation.