• KDI Journal of Economic Policy
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• v.11 no.2
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• pp.1-17
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• 1989

본고(本稿)에서는 최근 미국연방준비은행(美國聯邦準備銀行)의 Hallman Porter Small이 개발한 인플레추정방법, 즉 화폐수량식에 장기균형유통속도(長期均衡流通速度)($V^*$), 잠재생산력(潛在生産力)($Q^*$), 장기균형기준물가(長期均衡基準物價)(P*)등의 개념을 적용하여 인플레식(式)을 추정하는 방법을 우리나라에 적용하여 보았다. 이를 위해 $V^*$는 인플레의 변동에 의해 구조적(構造的)으로 변동(變動)될 수 있다는 점과 $Q^*$는 고용(雇傭)뿐 아니라 투자의 함수라고 가정하고 자본스톡 및 $Q^*$를 내생적으로 추정하는 등으로 $V^*$, $Q^*$의 개념을 재정립하였다. 추정결과(推定結果)에 의하면 87년초 이후부터 실질생산(實質生産) 잠재(潛在)GNP를 초과하게 되었으며 통화공급(通貨供給) 역시 확대되어 $P^*$가 P를 넘어서는 현상, 즉 물가상승압력(物價上昇壓力)이 누적되어 왔으며, 이에 따른 물가불안이 해소되기에는 정책대응여하에 따라 상당한 기간이 소요될 수도 있을 것으로 냐타났다. 즉, 시뮬레이션결과 종합해 보면 물가상승압력(物價上昇壓力)의 완화를 위해서는 투자진작을 통한 잠재생산력(潛在生産力)의 확충과 아울러 긴축기조(緊縮基調)의 유지라는 일견(一見) 상반(相反)되는 정책기조(政策基調)를 동시에 추진해 나가야 할 것으로 나타났다. 현재의 경기국면에 대한 대응책으로는 통화공급(通貨供給)을 확대시키는 단순한 총량적 정책보다는 긴축기조(緊縮基調)를 유지하면서도 통화(通貨)의 신축적(伸縮的)인 공급이 투자(投資) 고용(雇傭) 등의 생산부문(生産部門)으로 원활히 흐를 수 있도록 하는 동시에 금융구조(金融構造) 경제구조(經濟構造)를 개선해 나가는 미시적이고도 포괄적인 정책이 요구된다 하겠다.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.210-217
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• 1998

This paper describes the method for detection of the misfired cylinder using the pressure fluctuations occurred in the exhaust system on an MPI gasoline engine. If misfire is occurred in the cylinder of the gasoline engine, the power of engine gets lost, the fuel consumption and the exhaust emission are increased and the vibration is caused by unsteady torque. Therefore early detection and correction of misfire play a very important role in the proper performance and the exhaust emission. This paper suggests method of misfire detection which affect engine performance. The method is a comparison of average pressure index during the displacement period. Experimental results showed that the method using the pressure fluctuations in the exhaust system is proven to be effective in the detection of misfire on gasoline engine regardless loads and revolutions of the engine. In addition, this method, using the pressure fluctuations in exhaust system is easier than other methods and is not a need of additional reconstruction of engine.

• Nuclear industry
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• v.7 no.4 s.50
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• pp.86-87
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• 1987

미국원자력규제위원회(NRC)의 조사에 의하면 배관파단의 원인은 파단부 부근의 배관내면이 심하게 감육하고 있으며 원자로 트?후의 2차계의 압력변동에 견디지 못했기 때문이라고 보여지고 있다.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.169-171
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• 2003

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.520-526
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• 2012

The appearance of the negative differential pressure(NDP), in which the shot base pressure is higher than the breech pressure, indicates that a potential damage on the gun system is increased. In order to safeguard the gun system, the igniter must be designed to minimize the NDP during the firing process. From this reason, the effect of igniter's burning rate on the NDP of the interior ballistics has been investigated through the numerical simulations. The NDP has been increased with increment of the coefficient in the burning rate of the igniter. A sudden change of the chamber pressure has been shown in case of using a singular coefficient.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2007.10a
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• pp.19-36
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• 2007

When the trains runs at a high speed in the tunnel, passengers feel a pain in the ear that fast pressure fluctuation inside the tunnel being delivered with pressure fluctuation inside the passenger car. These phenomena are called "aural discomfort". Aural discomfort increase the passengers' uncomfort so that it is decreased a service level and serious case, it is able to damage the ear of the passenger. therefore aural discomfort must be considered the high-speed railroad tunnel cross-section design. To solve the problem of aural discomfort in a railway tunnel, some countries have standards on aural discomfort. It has been studied that different countries have different standards on aural discomfort. For that reason, the criteria of aural discomfort was reviewed through the standards of Kyungbu HSR line and different countries in this paper. And then Numerical Analysis of the Characteristics with tunnel cross-section change has been used for the selection of the optimum cross-section of Honam. The numerical analysis results were compared to field test results in order to verifying the reliability of the numerical analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.80-85
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• 2013

This paper describes a probabilistic structural design method of composite propulsion system by comparing safety factor based on average value and allowable value with structural reliability. Generally, the required structural safety factor and reliability of composite pressure vessel are 1.5 and 0.999, respectively. In the case of structural design using average strength, the safety factor which satisfies the required structural reliability depends on the variation of fiber strength. However, the structural design using allowable value shows constant safety factor for the variation of fiber strength, because the allowable value of fiber strength is calculated by considering the variation of fiber strength. Through the analysis results, it was known that the fiber strength is the most important design random variable for the structural design of composite pressure vessel and the variation of fiber strength must be minimized to develop the high performance composite propulsion system.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.1
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• pp.8-18
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• 2002

In this paper, wave energy absorption of OWC(oscillating water column) device is analyzed. The analytic model consists of a partially immersed circular vertical cylinder open at its end and an air turbine connected with the air chamber. The boundary value problem is decomposed into scattering problem related to scattering by an incident wave in the absence of a pressure variation and radiation problem describing the flow due to an oscillating pressure in the absence of an incident wave. By invoking the continuity of an air flow inside the chamber, the oscillating pressure in a chamber is derived. With oscillating pressure, the mean power absorbed by OWC device and the capture width are obtained. In numerical calculation, the induced volume flux across the internal free surface of the chamber in the scattering and radiation problem and the maximum capture width are compared with various design parameters such as radius and submergence depth of chamber and wave conditions. The maximum capture width obtained by choosing the optimal value of turbine constant occurs at the first resonant mode (Helmholtz mode) among the natural frequencies of a circular cylinder chamber.

• The Journal of the Acoustical Society of Korea
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• v.27 no.3
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• pp.103-110
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• 2008

Strategically, the Patrol Killer Medium (PKM) ought to run at high speed that produces largely vibration by propeller, in a consequence, the vibration gradually deterioratescrews' working condition and increases the possibility of SONAR detection. In this paper, we propose the propeller damper, which is one of waysto reduce the vibration induced by the propeller, and simulate the ability of the damper numerically. The propeller damper was designed to apply to an isolated plate at the bottom flat board of ship which is directly affected by the fluctuating pressure. The dynamic pressure for the stern part of the PKM is calculated by using the DnV rule and the numerical analysis when the propeller damper applied or not, is performed with ANSYS at the isolated plate that simplified. From the analysis, the damping effect of the proposed propeller damper is confirmed and the reduction ratio for each compartment is estimated based on the experimental data in the PKM.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.147-152
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• 2002

본 연구에서는 검증된 Bench급 석탄 가스화 공정에 대하여 개발된 동적모사 프로그램을 중잔유 가스화 공정 모델에 적용하여 가스화 성능에 크게 영향을 미치는 주요변수, 즉 시료 투입비, 산소 공급비, steam 공급비 및 압력조절밸브 열림궤도의 영향을 파악하고, 공정변수들의 동특성을 해석하였다. 가스화기의 부하변동에 따른 주요 공정 변수들의 변동경향 및 시상수에 대한 신뢰성 있는 모사결과를 얻을 수 있었으며, 개발된 모델을 사용하여 중잔유 가스화 공정설계를 위한 기초 자료를 마련하였다.