• Cement
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• s.150
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• pp.47-52
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• 1999

• 발명특허
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• v.4 no.12 s.46
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• pp.36-36
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• 1979

• The tire
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• s.135
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• pp.45-49
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• 1988

• Journal of Korean Electronics
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• v.9 no.9
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• pp.28-31
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• 1989

• Science of Emotion and Sensibility
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• v.12 no.4
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• pp.403-410
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• 2009

The purpose of this study was to find whether there is sound quality difference among mobile service providers in terms of ringtone in mobile phones, and identify factors that contribute to the difference of sound quality. A series of experiments were performed to identify the source of sound difference while controlling brand factor of the leading company. Mobile service provider, phone manufacturer, phone model variation, specific music genre and contents provider factors were examined. The results showed there was sound quality difference among mobile service providers. The difference comes from mobile phones provided to service provider and sound contents. There was difference in sound quality among same models that provided to different service providers. The different sound making process contributed to the difference of sound quality. The genre effect was not clear. To complement the limitation of samples used, an interview with the sound expert of mobile device was performed. The results showed hardware parts used and careful tuning of the device can influence to the sound quality of the mobile phone.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.698-703
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• 2014

Currently, demand of liquefied natural gas as an alternatice energy inceases because of depletion of fossil fuels. it is accompanied by inceasing demand of LNG ship. Consequentially, it is expected that demand of bellows for LNG ship increase. The material used for LNG vessels's bellows is an alloy of INCOLOY 825 and STS316L, which are strong against low-temperature brittleness and seawater corrosion. This study establishes the welding condition of LNG vessel's bellows material in extremely low temperature, and analyzes the formability of weld through Erichsen Test. When welding was conducted at optimal condition, tensile strength of weld presneted strength value up to 90% compared with base metal. As results of formalbility through Erichsen test, very good weld that failure occrued in base metal was gotten.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.665-668
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• 2008

Recently the city construction and the concrete structures are more becoming extra weight and the efficient use of the space by the population intensively and follow in industrial intensive commerce and the residence commerce composition building which leads the high story of the building. Consequently the high rise of the building which space applies efficiently in objective which will increase continuously. Also with high rise of buildings durability it will be able to increase the life of the structure is emphasized and the concrete structure is demanding the more high strength.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06b
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• pp.308-312
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• 2010

휴대폰 시장은 전세계 보급률이 2007년에 75%정도를 차지할 만큼 거대하다. 이러한 휴대폰 시장은 개발도상국에서의 규모 확대와 선진국의 Second Phone 경향의 증가로 인해 지속적으로 확대되고 있다. 이제 휴대폰은 더 이상 단순한 전화기를 벗어나 통합멀티미디어화 되어가는 추세이다. 휴대폰이 통합멀티미디어 제품으로 변모함에 따라 다양한 기능을 탑재한 차세대 제품을 설계해야 하는 연구자들은 여러 요인들을 고려해야 하는데 그 중에서도 가장 중요한 요인이 바로 사용자 인터페이스와 배터리 수명이다. 휴대폰의 통합멀티미디어화는 다양한 기능과 편리한 인터페이스를 제공하지만 이로 인해, 배터리 수명은 줄어들었다. 전력소모가 많은 휴대폰의 기능을 제한하는 방안을 사용한다면 배터리 수명은 증가하겠으나, 이는 높아져 가는 소비자의 요구를 만족 시킬 수 없다. 그러므로 본 논문에서는 이와 같은 문제를 해결하기 위해서 음향적 기능과 촉각적 기능을 사용하였을 때 소모되는 전력 패턴을 분석하고자 한다. 본 논문의 실험은 벨소리(음향적 기능)의 박자별 전력 소모량과 진동(촉각적 기능)의 주기에 따른 전력 소모량, 그리고 진동벨(음향적 기능 + 촉각적 기능)은 벨소리를 포함한 진동의 길이와 주기에 따른 전력량을 측정하였다. 본 논문에서는 전력을 측정하기 위하여 인스펙터를 사용하였고 측정 휴대폰은 삼성전자의 SCH-W550 모델을 이용해서 실험을 하였다. 실험결과, 본 논문에서 실험한 세 가지 방법 중에서 진동벨을 이용할 경우 사용자 인터페이스 설계에 보다 효과적임을 확인할 수 있다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.46-52
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• 2024

The structural safety of expansion joints for piping systems has been drawing attention owing to ruptures and leaks of water pipes caused by earthquakes and road subsidence at soft ground. In general, metal bellows are installed as expansion joints to prevent various damages in the piping system. In this study, the seismic performance of a valve chamber system was evaluated by performing earthquake shaking table tests. To validate the benefits to structural safety of metal bellows in connecting steel pipes to valve chambers, the seismic tests were conducted on expansion joints (bellows) and general pipping, and the results were compared for durability. Strain gauges were attached to measure the effects of the input motion. As a result of the shaking table test, it was confirmed that the strain of the valve chamber structure and inflow or outflow steel pipes were decreased in 1/100, 1/20 by applied to the expansion joints.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.3
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• pp.21-32
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• 1994

The Problem of mechanical vibration is investigated for an automotive exhaust system. The vibrational reduction effect is systematically evaluated according to the attachment of the exhaust system. Moreover, the optimal attachment position of bellows is determined from the viewpoint of vibration isolation. The structure is analysed by the finite element technique where the geometry, the mass, the stiffness and the damping properties of the exhaust pipe are modeled. The validity of the developed model is verified by comparing with the experimental results. An optimization is carried out by the quadratic approximation algorithm. The reaction transferred to an automobile body by the hanger is considered ad the objective function. It is shown that the exhaust system which has the bellows at the optimal position is more effective for the vibrational characteristics than the others. It is also proved that this analytical method is quite useful in the design stage of the exhaust system.