• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.564-567
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• 1997

In the design of structure the forces acting on the structure are important parameter for noise and vibration control. However, in the complex structure, the forces at the injection point on the structure cannot be measured directly. Thus it is necessary to find out indirect force evaluation method. In this paper forces have been measured with in-situ vibration responses and system information. Three existing techniques of indirect force measurement, viz. direct inverse, principal component analysis and regularization have been compared. It has been shown that multi-vibration responses are essential for the precise estimation of the forces. To satisfy those conditions, Rotary compressor is adopted as test sample, because it is very difficult to measure the injection forces from internal excitation to shell. It has also been obtained that relatively higher force is transmitted though three welding paths to the compressor shell. It shows a good agreement between direct and indirect force evaluation with curvature shell and plate and is investigated the possibility of force evaluation of rotary compressor as a complex structure.

• Journal of Power System Engineering
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• v.3 no.2
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• pp.26-33
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• 1999

Pressure pulsation Inside the discharge and suction cavity of rotary and scroll compressor are often a major source of objectionable noise and vibration. The key factor of these noise and vibration is due to the cavity resonance. It is not only necessary to understanding the characteristics of pulsation in order to reduce the excitation force of gas to the cavity but also to verifying the phenomena of cavity resonance. For the purpose of these understandings, measurement and simulation of cavity resonance can lead to a better understandings how they occur and be very important to identify the ways to reduce the noise efficiently. In this paper, modeling of the cavity(internal acoustics inside the shell) is discussed and simulated using FEM. Results from the simulation are compared with those measurement in experiments. In describing of cavity mode by experiments, it is very important to specify the exact conditions under which they are measured. Finally, this paper shows the one example of reduced cavity resonance in the compressor.

• Journal of the Semiconductor & Display Technology
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• v.9 no.1
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• pp.67-71
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• 2010

Head up display’s cooling system is auto-diagnosed resulting from the external environment. The quantity of heat depending on this Head up display’s cooling system layout determines the speed of FAN for system cooling. In other words, a system’s heat quantity is planned through the air density depending on altitude, the amount of wind in air depending on FAN control condition, and the algorithm that is proportional to delta temperature. To detect the altitude, we use the criteria of delta T, which is determined by the subtracted value of LED junction temperature, and atmospheric temperature that is recorded on the Head up display system. Depending on the classification of delta T value, the altitude section is determined. While we can use GPS as the tool to detect the altitude, we should predict the change of the air density as the altitude alters, and should not just measure the altitude. And the value of delta T is used as the criterion of detecting the altitude for increasing the cooling efficiency of the car’s inner Head up display system with reflecting the speed of the FAN dependent upon the air density. In our theory, altitude is depending on the value of delta T and stabilizing or maintaining the system’s temperature by changing FAN’s rpm depending on determined value of altitude.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.5
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• pp.370-376
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• 2004

The overall aim of this paper is to determine coupling loss factor of welding point between shell and cylinder using loss factor and structural loss factor. For this purpose, two kinds of loss factor were adopted. One is loss factor of each sub structure, another is structural loss factor based on the complex welded or assembled structure. Using these two parameters, it ispossible to derive the coupling loss factor which represent characteristic condition of SEA theory. Coupling loss factor of conjunction in complex structure was expressed as power balance equation. The derived equation for a coupling loss factor has been simplified on the assumption of one way (uni-directional) power flow between multi-sub structures. Using these conditions, it is possible to find the equation of coupling loss factor expressed as above two loss factors. To check the effectiveness of above equation, this paper used two-stage application. The first approach was application between simple cylinder and shell. The next was adopted rotary compressor. Rotary compressor has three main conjunctions between shell and internal vibration part. This equation was applied to find out the optimum welding point with respect to reduce the noise propagation. It shows the effective tool to evaluate the coupling loss factor in complex structure

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.122-126
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• 1984

Tube drawing process is more sensitive to the friction coefficient but it is a hard task to analyze it's disposition qualitatively. This paper aims to calculate the mean friction coefficient from author's direct equation which amended from general rod drawing process, and compare the result with SACHS' or WILLIAM'S. From this study, the thickness change was inspected in multi-pass drawing. The thickness affected with the mean friction coefficient and the thickness was deformed more thicker than initial thickness on the condition of good lubrication. For the sake of a good estimation of mean friction coefficient, the radial force of die must be considered when the drawing process has some more area reduction about more than 10 percents.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.130-139
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• 2007

As increasing the usefulness of wireless communication, there are developing the environment of ubiquitous that is combined the network of wireless and wire communication combinate type in various filed and in this network environment, u-campus constructions, based on ubiquitous sensor network, is developing. u-Campus is the new type campus which applies to ubiquitous computer technology and wireless network one. at this thesis, it is designed u-campus construction using zigbee technology with u-campus basic technology. u-Campus service, being subject to zigbee wireless communication skills, presents the members an convenient service using zigbee network.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.969-972
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• 2003

The overall aim of this paper is to determine coupling loss factor of welding point between shell and cylinder using loss factor and structural loss factor. For this purpose, two kinds of loss factor were adopted. One is loss factor of each sub structure, another is structural loss factor based on the complex welded or assembled structure. Using these two parameters, it is possible to derive the coupling loss factor which represent characteristic condition of SEA theory. Coupling loss factor of conjunction in complex structure was expressed as power balance equation. The derived equation for a coupling loss factor has been simplified on the assumption of one way(nl- directional) power flow between multi-sub structures. Using these conditions, it is possible to find the equation of coupling loss factor expressed as above two loss factors. To check the effectiveness of above equation, this paper used two stage application. The first approach was application between simple cylinder and shell. The next was adopted rotary compressor. Rotary compressor has three main conjunctions between shell and internal vibration part. This equation was applied to find out the optimum welding Point with respect to reduce the noise propagation. It shows the effective tool to evaluate the coupling loss factor in complex structure

• The Journal of Fisheries Business Administration
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• v.47 no.1
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• pp.1-20
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• 2016

The purpose of this study is to assess the effects of outlook project for olive flounder, from the view point of price stabilization, market efficiency, and causality of the prices in different distribution channels. Analytical results show that the volatility of producer price of olive flounder has been significantly mitigated after the implementation of the outlook project. The market efficiency is estimated to be improved after implementing the outlook project although there is an inefficiency on price determination process in some producing regions. The causality test on the producer and wholesale price shows that producing stage leads the wholesale stage in forming the prices. It is found that Jeju leads the flounder price on the size of 500g and 2kg, while Wando leads the price of 1kg size. These estimation result as whole indicate that outlook project for olive flounder has accomplished the intended goals.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.11a
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• pp.241-247
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• 2000

날로 복잡해지고 거대해지는 시스템의 추세를 감안할 때 앞으로 시스템 분야의 주요 구성요소간 상호작용을 분석하여 최적의 시스템 운영방안을 도출하기 위해서는 시뮬레이션 기법의 도입이 필수적이다. Simplus 3D는 분석대상 시스템을 주요 객체 단위로 Model 상에 재구성하여 이들의 움직임과 주체적 의사결정 논리를 자체 서술어를 사용하여 묘사하도록 고안된 범용 그래픽 시뮬레이션 소프트웨어로 사용자가 정의한 Logic을 Procedure 또는 Function화하여 별도의 File에 저장하고 재활용 가능하며, 객체별 Logic Trace가 가능하여 객체 시나리오의 상세분석 및 Logic 디버깅이 용이하다. 또한 대상시스템의 특성에 따라 Macro한 수준의 개략적인 묘사부터 Micro한 수준의 제어 알고리듬에 이르기까지 묘사의 수준이 자유롭고, 시뮬레이션에 주로 사용되는 물류설비 및 Logic을 Module로 제공하며 필요시 Custom Logic을 추가할 수 있다. 분포형태는 일양분포, 지수분포, 정규분포 등 다양한 분포형태를 지원하며 9999개까지의 Random Number Seed 지정이 가능하다. 일반 PC에서도 실행 가능하며 3차원 Animation과 다양한 형태의 Report를 제공함으로써 비전문가나 의사결정자가 각종 대안에 대한 시뮬레이션 결과를 시각적으로 확인하여 쉽게 이해할 수 있도록 하였다. Simplus 3D는 현재까지 생산시스템, 항만 및 교통 등의 분야에 광범위하게 활용되고 있으며, 본 논문에서는 기아자동차 WBS 물류시스템 시뮬레이션 모델과 고속도로 톨게이트 시뮬레이션 모델을 활용사례로 소개하고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.83-92
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• 2000

Sound intensity method is well known as a visualization technique of sound field or sound propagation in noise control. Sound intensity or energy flux is a vector quantity which describes the amount and the direction of net flow of acoustic energy at a given position. Especially two dimensional sound intensity method is very useful in evaluating periodic characteristics and acoustic propagation mode of noise source. In this paper, we have studied the noise source Identification, acoustic sound field analysis, and characteristics of noise source of rotary compressor and scroll compressor for air conditioner using complex sound intensity method. Also we proposed a now method of time domain analysis which is used in evaluating of position of noise source in rotary and scroll compressor in this paper This paper presents the advantage, simplicity and economical efficiency of this method by analysing the characteristics of noise source with two dimensional complex sound intensity simultaneously.