• 한국음향학회지
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• 제15권6호
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• pp.47-51
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• 1996

실린더 운동방정식은 실린더 내에서 발생되는 소음 해석에 매우 중요하다. 그러므로, 지금까지 많은 학자들에 의해 실린더 운동방정식을 유도되었다[1]. 참고문헌[6]에서는, 새로 제안돈 실린더 운동방정식, Junger and Feit의 실린더 운동방정식 그리고 가정해에 의한 선형방정식으로, 실린더가 자유 운동을 할 때, 자유파수를 구하였다. 본 논문에서는 자유파수들의 분산곡선들을 이용하여, 두 실린더운동방정식을 비교하였고, 링주파수와 링확장주파수의 계산으로, 자유파수들의 분산곡선의 물리적인 의미를 부가하였다. 이 결과, 새로 유도된 실린더 운동방정식의 타당함을 보였다. 새로 제안된 실린더 운동 방정식을 이용하면, 산업현장에서, 실린더 내의 고체파에 대한 보다 정확한 분석을 할 수 있을 것으로 사료된다.

• 대한기계학회논문집
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• 제7권4호
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• pp.451-460
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• 1983

Computational four-equation turbulence model is developed and is applied to predict twodimensional unsteady thermal surface discharge into a reservoir. Turbulent stresses and heat fluxes in the momentum and energy equations are determined from transport equations for the turbulent kinetic energy (R), isotropic rate of kinetic energy dissipation (.epsilon.), mean square temperature variance (theta. over bar $^{2}$), and rate of destruction of the temperature variance (.epsilon. $_{\theta}$). Computational results by four-equation model are favorably compared with those obtained by an extended two-equation model. Added advantage of the four-equation model is that it yields quantitative information about the ratio between the velocity time scale and the thermal time scale and more detailed information about turbulent structure. Predicted time scale ratio is within experimental observations by others. Although the mean velocity and temperature fields are similarly predicted by both models, it is found that the four-equation model is preferably candidate for prediction of highly buoyant turbulent flows.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제3권1호
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• pp.14-22
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• 2000

The improved Green integral equation for the calculation of time-harmonic potentials in the radiation diffraction problem about a freely floating body in the presence of moderate or weak current is presented. The forward-speed Green function presented by Brard is used. The correct free surface boundary conditions on the physical free surface are employed as well as an appropriate boundary conditions on the non-physical inner free surface. The default in the existing Green integral equation as well as in the source integral equation is discussed in detail.

• 한국전자파학회논문지
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• 제25권9호
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• pp.919-929
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• 2014

최근 전자기기의 활용도가 높아짐에 따라 전자기파에 대한 안정성이 요구되었다. 소형화 전자기기 및 다양한 전자부품들은 맥스웰 방정식 (Maxwell Equation)으로 해석되었으나, 복잡도가 높은 대형 구조물에 대한 전자기파 안정성이 요구되는 현시점에 맥스웰 방정식은 여러 한계점을 가지고 있다. 본 논문에서는 복잡한 대형 구조물을 확률론과 위상학적 모델링을 연동하여 해석하고자 한다. 특히, 확률론을 바탕으로 한 해석 방법인 PWB(Power Balance) Method와 BLT(Baum-Liu-Tesch) 방정식을 연동하여 대형 구조물의 주파수 응답을 풀이할 경우, 해석시간이 상당히 줄어드는 장점이 있다. 본 논문에서는 복잡한 대형구조물의 예로 이중 공진구조 내부에 PCB가 존재하는 경우를 고려해 보았다.

• Computers and Concrete
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• 제9권4호
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• pp.275-291
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• 2012

The service loads are often decisive in the design of concrete structures. The evaluation of the cracking moment, $M_{cr}$, is an important issue to predict the performance of the structure, such as, the deflections of the reinforced concrete beams and slabs. To neglect the steel bars of the section is a simplification that is normally used in the computation of the cracking moment. Such simplification leads to small errors in the value of this moment (typically less than 20%). However, these small errors can conduce to significant errors when the values of deflections need to be computed from $M_{cr}$. The article shows that an error of 10% on the evaluation of $M_{cr}$ can lead to errors over 100% in the deformation values. When the deformation of the structure is the decisive design parameter, the exact computing of the cracking moment is obviously very important. Such rigorous computing might lead to important savings in the cost of the structure. With this article the authors wish to draw the attention of the technical community to this fact. A simple equation to evaluate the cracking moment, $M_{cr}$, is proposed for a rectangular cross-section. This equation leads to cracking moments higher than those obtained by neglecting the reinforcement bars and is a simple rule that can be included in Eurocode 2. To verify the accuracy of the developed model, the results of the proposed equation was compared with a rigorous computational procedure. The proposed equation corresponds to a good agreement when compared with the previous approach and, therefore, this model can be used as a practical aid for calculating an accurate value of the cracking moment.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.211-213
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• 2003

Evaluation of bond strength of a fire-damaged reinforced concrete structure for determining whether to reuse, reinforced, or abandon the structure is very important. Recently, calculating method for changes in bond strength of rebars is proposed by C. Chiang. The equation is relating the ratio of residual bond strength, R, to temperature, T, and exposure time, t. This study presented and verified a general process for evaluating damage to bond strength of RC structure arising from high temperature.

• 전기전자학회논문지
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• 제10권2호통권19호
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• pp.97-102
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• 2006

In this paper, a new simple integral variable structure controller is designed with incorporating the actuator dynamics. The formulation of the VSS (variable structure system) controller design includes integral augmented sliding surface and the dynamics of the actuator expressed as the state equation. An illustrative example is given to show the effectiveness of the developed controller.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.643-647
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• 1990

Gunner primary sight(GPS) stabilization system lays line of sight(LOS) to find out a target and transmits informations to the fire control system (FCS). In a moving vehicle, accuracy of LOS and FCS depends on the design of GPS and servomechanism system. The heavy vibration of vehicle on the severe off-road environment degenerates the stabilization capability of GPS. In this study, to stabilize of elevation for GPS using the variable structure control, we derived the dynamic equation of GPS system and designed the variable structure controller. Computer simulation results fulfilled the static and dynamic stability of GPS using the variable structure control.

• Journal of applied mathematics & informatics
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• 제12권1_2호
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• pp.307-312
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• 2003

In this paper, a special incidence structure is designed based on (v, k+1, 1)-configuration, a subset of symmetric balanced incomplete block design, where ν = k$^2$+ k + 1. The time complexity required for desinging this incidence structure is O(equation omitted).

• Kyungpook Mathematical Journal
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• 제33권1호
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• pp.61-67
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• 1993