• Journal of Advanced Marine Engineering and Technology
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• 제27권3호
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• pp.381-387
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• 2003

Engine noise consists of the noise radiated from an engine structure and noises from engine ancillaries such as a turbocharger fuel injection system, and alternator. The noise of these ancillaries might be incorrectly evaluated in the aspect of the noise contribution to engine noise because the noise reflection effect of their neighbor engine structure is easily ignored. Consequently, noise source identification should be misled. This study investigates the fact that the engine structure located around an alternator reflects alternator noise, and the reflected noise acts as another alternator noise source in a heavy-duty diesel engine. The result shows that the alternator noise can be correctly estimated in engine noise by properly including the noise reflection effect.

• 한국자동차공학회논문집
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• 제15권3호
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• pp.79-84
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• 2007

Recently it is strongly required to develop the better fuel economy as well as basic power performance based on strict emission legislation. This paper focuses on studies of the engine cooling and ancillaries system among fuel economy factors in the developing stage. Firstly through the analysis of the current specifications, it is assessed whether each components may be designed properly, not overdesigned. Secondly, it is predicted how the fuel economy of each components can be improved. Finally the results are confirmed by vehicle field test equppted with the updatedcomponents. This study found good agreementbetween the prediction and the field test on the vehicle fuel economy improvements of the heavy duty engine vehicle with updated components such as engine cooling and ancilliaries.

• Wind and Structures
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• 제4권4호
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• pp.353-366
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• 2001

With respect to serviceability, antenna masts should be designed so that wind-induced motion will not cause unacceptable lack of transmission for broadcasting users and wireless communication. For such antenna masts with directional radio transmission the serviceability limit state is predominantly governed by the tolerable change of the broadcasting angle of the mounted antenna assembly and therefore by the tip distortion of the mast. In this paper it will be shown that refinements of the present state of design of antenna masts are possible by using the statistics of extremes applied to extreme wind situations and by consideration of the statistical and reliability requirements given by the operator such as frequency and return period of passing the serviceability limit.

• Asian Journal of Innovation and Policy
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• 제7권1호
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• pp.207-234
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• 2018

A manufacturer of a durable good typically purchases supplies, including parts for assembly - that are also useful for repairs - from independent "original equipment suppliers" with which it contracts. The manufacturer is a branded monopolist of its final assembled product. To put into effect also a monopoly of the replacement parts, it must stipulate in its arrangements with independent suppliers of the parts that they not supply such patented parts to any other buyer. Durable good owners would then only be able to obtain their requirements of replacement parts from the same company that supplied the durable. This would amount to a tie-in of replacement parts to the direct purchase of new durables. And that describes the apparently widespread practice of automobile manufacturers in India, as exposed in a recent case before the Competition Commission of India (Samsher Kataria v Honda Siel Cars India Limited and others). Here, I will argue that such tie-in enabled automotive manufacturers to more fully appropriate consumer surplus, which induced them to lower the price of new cars, sell more cars and also sell more repair parts. The tie-in expanded the auto parts industry and promoted new entry. The main restraint on expansion of India's automotive manufacturing is not monopoly. It is government protection in the form of tariffs on automobiles and auto parts.

• 한국수자원학회논문집
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• 제53권3호
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• pp.181-191
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• 2020

본 연구에서는 전지구수치예보모델의 예측성능에 주요한 영향을 주는 요소 중 하나인 토양수분 초기장을 적절히 생산하기 위해, 오프라인 Noah 지면모델을 구축하여 스핀업실험을 수행하고 그 변동특성을 살펴보았다. 스핀업실험은 지면기후장 생성과 목표연도에 대한 현실화의 2단계로 구성되었다. 첫 번째 단계의 지면기후장 생성은 2008~2017년 기간에 대해 평균한 대기강제력으로 10년 동안 지면모델을 반복적으로 수행하는 방식으로 이루어졌으며, 토양수분 모의가 평형상태에 도달하는데 소요되는 시간은 토양깊이와 코펜 정의에 기반한 기후구 특성에 따라 차이가 컸다. 토양 첫 번째 층은 극지역에서 가장 길었고, 두 번째 층 부터 네 번째 층까지는 건조지역에서 평형상태에 도달하는 시간이 가장 늦어 최대 7년 내외의 시간이 소요되었다. 결과적으로 10년의 spin-up을 거치면 지면모델이 평형상태에 도달함을 알 수 있다. 이 소요시간은 지상기온과 강수량과 음의 상관관계를 보였다. 두 번째 단계에서는 2018년을 목표연도로 설정하고 지면기후장을 이용하여 추가 적분을 수행하고, 그 결과 6개월 이내에 지면모델에서 모의된 토양수분, 지표기온, 증발산량은 2018년 지면상태에 도달하는 것을 확인하였다. 이에 구축된 오프라인 Noah 지면모델 스핀업 시스템은 안정적으로 전구수치예보모델의 토양수분 초기장을 생산함으로써 전지구수치모델에 결합된 지면모델의 물리과정과 기초자료가 변하더라도 유연하게 대응할 수 있는 가능성을 확인하였다.