• 소음진동
• /
• 제10권4호
• /
• pp.575-583
• /
• 2000

In this paper, we design a vibration control system that includes a 3-D.O.F. mass-spring-damper structure for the analytical model of a building that is excited at the base of this structure by an external dynamic force, and one Active Mass Damper(AMD) on the top of this structure to generate control forces fro attenuation of the structural response. Two robust controllers based on $\mu$-synthesis and H$\infty$ optimal control are designed for the structural system to show that the performance of a control system can be degraded by some parameter uncertainties such as mass, stiffness coefficients, and/or damping coefficients. The performance of the two controllers are compared in terms of nominal performance, robust stability and robust performance by simulations.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.235-240
• /
• 2001

A four degrees of freedom (dof) motion platform for bicycle simulator is developed. The motion platform, capable of the vertical linear and three angular motions, is designed based on analysis of the typical motion characteristics revealed by the existing six dof bicycle simulator. The platform essentially consists of two parts： the three dof parallel manipulator, consisting of a moving platform, a fixed base and three actuators, and the turntable to generate the yaw motion. The nonlinear kinematics and dynamics of the three dof parallel manipulator with multiple closed loop chains are analyzed for tracking control of the motion platform. The tracking performances of the three control schemes are experimentally compared： the computed torque method (CTM), the sliding mode control (SMC) and the PD control. The CTM and SMC, incorporated with the system dynamics model, are found to be equally better in performance than the PD controller, irrespective of the presence of external disturbance.

• Structural Engineering and Mechanics
• /
• 제46권1호
• /
• pp.19-37
• /
• 2013

The optimum design of base isolation system considering model parameter uncertainty is usually performed by using the unconditional response of structure obtained by the total probability theory, as the performance index. Though, the probabilistic approach is powerful, it cannot be applied when the maximum possible ranges of variations are known and can be only modelled as uncertain but bounded type. In such cases, the interval analysis method is a viable alternative. The present study focuses on the bounded optimization of base isolation system to mitigate the seismic vibration effect of structures characterized by bounded type system parameters. With this intention in view, the conditional stochastic response quantities are obtained in random vibration framework using the state space formulation. Subsequently, with the aid of matrix perturbation theory using first order Taylor series expansion of dynamic response function and its interval extension, the vibration control problem is transformed to appropriate deterministic optimization problems correspond to a lower bound and upper bound optimum solutions. A lead rubber bearing isolating a multi-storeyed building frame is considered for numerical study to elucidate the proposed bounded optimization procedure and the optimum performance of the isolation system.

• Clinics in Shoulder and Elbow
• /
• 제24권3호
• /
• pp.141-146
• /
• 2021

Background: The purpose of the present study was to determine how long superior screws alone or in combination with posterior placement of metaglene screws protruding and penetrating into the scapular spine in reverse total shoulder arthroplasty affect the strength of the scapular spine in a fresh cadaveric scapular model. Methods: Seven fresh cadaver scapulas were allocated to the control group (short posterior and superior screws) and seven scapulars to the study group (spine base fixation with a four long screws, three with both long superior and long posterior screws). Results: The failure load was lower in the spine fixation group (long screw, 869 N vs. short screw, 1,123 N); however, this difference did not reach statistical significance (p>0.05). All outside-in long superior or superior plus posterior screws failed due to scapular spine base fracture; failures in the short screw group were due to acromion fracture. An additional posterior outside-in screw failed to significantly decrease the failure load of the acromion spine. Conclusions: The present study highlights the significance of preventing a cortical breach or an outside-in configuration when a superior or posterior screw is inserted into the scapular spine base.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.447-447
• /
• 2000

This paper proposes an Object-oriented model for Generic Equipment Model(GEM) which is applied to semiconductor processing Equipment. A proposed implementation model for GEM consists of three modules : a module to convert SECS-II message and a module to transmit messages between GEM and a physical equipment. The proposed Object-oriented model for GEM has advantages in reuse and user management from the point of view of development program. Especially, this paper proposes a GEM agent COM, which is a base of GEM, transmits messages and events among modules. This Object-oriented model is analysed and developed by using UML.

• Korean Journal of Hydrosciences
• /
• 제10권
• /
• pp.17-34
• /
• 1999

The SSARR model adopting Is(integrated snowband) watershed model is applied to Nakdong River basin for lowflow analysis. The IS watershed model is added to new version of the SSARR which has functions of simulating evapotranspiration, infiltration and lower zone routing. It provieds annual water budget informations as an output file and can be operated by interactive mode. Sensitivity analysis for both cases of high and lowflows was carried out, which becomes the knowledge base for model calibration. Model verification was performed using the relative errors of highflows and absolute errors of lowflows at the control points. Monthly water budget analysis was done by IS watershed model, and is reveals that runoff coefficient is 52.6%.

• Corrosion Science and Technology
• /
• 제22권5호
• /
• pp.377-386
• /
• 2023

Aircraft washing is performed periodically for corrosion control. Currently, the aircraft washing interval is qualitatively set according to the geographical conditions of each base. We developed a washing interval determination algorithm based on atmospheric corrosion environment monitoring data at the Republic of Korea Air Force (ROKAF) bases and United States Air Force (USAF) bases to determine the optimal interval. The main factors of the washing interval decision algorithm were identified through hierarchical clustering, sensitivity analysis, and analysis of variance, and criteria were derived. To improve the classification accuracy, we developed a washing interval decision model based on an artificial neural network (ANN). The ANN model was calibrated and validated using the atmospheric corrosion environment monitoring data and washing intervals of the USAF bases. The new algorithm returned a three-level washing interval, depending on the corrosion rate of steel and the results of the ANN model. A new base-specific aircraft washing interval was proposed by inputting the atmospheric corrosion environment monitoring results of the ROKAF bases into the algorithm.

• 한국항공우주학회지
• /
• 제36권9호
• /
• pp.867-873
• /
• 2008

모델 기반의 가상 비행제어 시스템 구성은 동시공학이 중요시되는 개발환경에서 FBW 비행제어 시스템 검증 및 확인에 매우 유용하게 사용된다. 본 논문에서는 가상 비행제어 시스템을 구성하기 위한 이중구조 개념에 대해서 살펴보고, 고고도 정찰용 무인기에 적용된 이중구조 시스템에 대해서 분석하였다. 마지막으로, 분석된 비행제어 시스템을 바탕으로 Simulink 기반의 가상 비행제어 시스템을 구성하였고, 치명적인 고장모드에 대한 시스템의 동작 상태를 검증하였다.

• 한국항행학회논문지
• /
• 제12권5호
• /
• pp.470-482
• /
• 2008

본 논문에서는 유비쿼터스 환경을 위에 컨텍스트 정보를 이용한 역할기반 접근제어 모델을 제안한다. 컨텍스트 정보를 이용한 접근제어의 기본적인 개념은 어떠한 정보나 객체에 접근할 수 있는 권한을 역할에 배정하여, 사용자를 그 역할에 할당함으로써 정보나 객체에 접근할 수 있는 권한을 획득할 수 있도록 하는 것이다. 그러므로 사용자는 자신에게 할당된 역할과 그 역할이 지니고 있는 권한에 맞는 정보 또는 객체에 접근하게 됨으로써 안전하게 정보나 객체의 이용을 보장할 수 있도록 한다. 본 논문에서 제안하는 모델은 GEO-RBAC 모델에서 부족한 제약 사항을 고찰하여 새로운 제약 조건을 제시하고 다양한 경우에서의 역할 충돌을 고려하였다. 또한 GEO-RBAC 모델에 적합한 위임 모델을 제안하기 위하여, 기존 모델의 장/단점을 분석하고 이를 개선하여 GED-RBAC에 적합한 위임 모델을 제안한다.

• 전기학회논문지P
• /
• 제52권1호
• /
• pp.1-8
• /
• 2003

The paper proposes instantaneous torque control of IPMSM for maximum torque drive of torque and current plane. The control scheme is based on the mathematical model of the motor and is applicable to the constant torque and field weakening operations. The scheme allows the motor to be driven with maximum torque per ampere(MTPA) characteristic below base speed and it maintains the maximum voltage limit of the motor wide field weakening and the motor current limit under all conditions of operation accurately. For each control mode, a condition that determines the optimal d-axis current $^id$ for maximum torque operation is derived. The proposed control algorithm is applied to IPMSM drive system for drive of wide speed range, the operating characteristics controlled that maximum torque control are examined in detail by simulation.