• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.395-400
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• 1998

A design of PIDA (Proportional-Integral-Derivative-Acceleration) controller for the third-order plant using the CDM (Coefficient Diagram Method) is presented. Using CDM, the closed-loop system with the designed PIDA controller can be made stable and satisfied both transient and steady state response specifications without any adjustment. The effect of output step disturbance can also be lastly rejected. The fast step response of the controlled system can be achieved by reducing the equivalent time constant. The MATLAB's simulation results show that the performances of the designed controlled system using CDM is better than the performances of the controlled system using PIDA controller designed by its own technique.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.45-47
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• 2011

Finishing materials used during the construction of reinforced concrete structures aid in providing resistance to carbonation and help ensure the durability of a structure. However, detailed examinations of this phenomena using data gained from long-term outdoor exposure are not only lacking, but also are not taken into account as factors affected by the local environment. In this research, the velocity coefficient in terms of carbonation is compared as a difference according to the local region and the averaged annual temperature, and the carbonation-preventive effects of finishing materials are analyzed. As an outcome of this study, the results of long-term carbonation can be evaluated from carbonation resistance R induced by an acceleration carbonation test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1002-1004
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• 1996

In this paper, presented are the results of observability analysis for the vehicle maneuver during In-Flight Alignment of SDINS. The target system for observability analysis is 10th order one. Three trajectories for IFA are considered. To analyze the observability of the time varying system, correlation coefficient is used and to measure the degree of observability of the given system, simulation is carried out using covariance matrix. The results of simulation show that trajectories which are having continuous changes in attitude and acceleration of system is superior to straight trajectory in correcting navigation errors.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.483-489
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• 2005

Based on a two-degree of freedom vehicle model, this paper investigates ride comfort for a heavy off-road vehicle mounted a nonlinear hydropneumatic spring, which is influenced by nonlinear stiffness and damping characteristics of the hydropneumatic spring. Especially, the damping force is derived by applying H. Blasius formula in modeling process according to the real physical structure of the hydropneumatic spring, and the established model of nonlinear stiffness characteristics have been validated by experiments. Furthermore, the effects of parameter variations of the hydropneumatic spring, such as initial charge pressure and damping coefficient, on body acceleration, suspension deflection and dynamic tire deflection are also investigated.

• 터널과지하공간
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• 제6권3호
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• pp.239-244
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• 1996

Cracks have influence on the physical and mechanical and, more importantly, on the engineering properties of the rock. Physical properties including the volumetric deformation coefficient, electrical resistivity, seismic wave velocity, and the mechanical properties such as the elastic constants and strength of rock are affected significantly by the presence of cracks of various sizes. An experimental program was undertaken to investigate the effect of a finite line crack on the diffraction of the plane compressional wave. Horizontal and vertical components of displacement and acceleration curve were obtained using a single-source and multi-receivers system. A theoretical model from numerical analysis implementing the finite element method was compared with the measured data.

• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.25-31
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• 2019

In this study, a new adhesion evaluating equipment and data processing methods were developed to overcome some limitations of existing evaluating equipment. Nano-diamond coated tool is a specimen of experiment. When applying frictional force and shear force on the specimen by a rotating polishing pad, delamination occurs at a moment. During each experiment, the vibration, load, and torque is obtained by accelerometer, loadcell and torque s+ kpensor. Frictional force and coefficient of friction are obtained by calculating torque and load. Based on FFT transformation, acceleration is processed and analyzed. As a result, the moment of delamination and the load at that time can be detected by the new developed equipment and measurement system. Finally, we call this load as an Adhesion force.

• 국제초고층학회논문집
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• 제10권3호
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• pp.229-242
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• 2021

Dynamic characteristics of tall building structures with double negative stiffness damped outriggers (2NSDO) are parametrically studied using the theoretical formula. Compared with one negative stiffness damped outrigger (1NSDO), 2NSDO can achieve a similar maximal modal damping ratio with a smaller negative stiffness ratio. Besides, the 2NSDO can improve the maximum achievable damping ratio to about 30% with less consumption of an outrigger damping coefficient compared with the double conventional damped outriggers (2CDO). Besides, the responses of structures with 2NSDO under fluctuating wind load are investigated by time-history analysis. Numerical results show that the 2NSDO is effective in reducing structural acceleration under fluctuating wind load, being more efficient than 1NSDO.

• 수산해양기술연구
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• 제51권1호
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• pp.71-78
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• 2015

In order to deduce an objective evaluation method of motion seasickness incidence (MSI) by ship motions during underway in irregular waves and to present the fundamental data of passenger comfort on the yacht and the passenger ship according to the result, the MSI of the trainees by the questionnaires was analysed and compared with the rate of variation of salivary ${\alpha}$-amylase activity (VSAA) on the training ship "A-ra ho" of Jeju national university. Relationship between rate of variation (x) by salivary ${\alpha}$-amylase activity and motion seasickness incidence (y) was described by the equation, MSI(%) = 0.6073 x + 12.189 including the correlation coefficient ($R^2=0.9853$). The result obtained through the rate of variation of salivary ${\alpha}$-amylase activity which was the quantitative evaluation method for ship motions causing seasickness was most affected by z-vertical acceleration and occurred within the frequency range 0.1 to 0.3Hz centered on 0.2Hz, and the simulation result based on this finding showed the motion seasickness rate at approximately 4% lower than the rate obtained through the survey.

• 한국융합학회논문지
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• 제11권10호
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• pp.355-361
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• 2020

스쿼트는 장소에 제약 없이 효과적으로 하체 근력을 증진시킬 수 있는 운동이다. 스쿼트 시 잘못된 자세로 인한 부상이 빈번하게 발생하고 있으며, 부상을 예방하기 위해서는 적절한 각도를 유지하며 운동하는 것이 중요하다. 본 연구에서는 허벅지에 착용된 단일 관성 센서 모듈을 이용하여 스쿼트 각도를 측정할 수 있는 시스템을 개발하고 검증하였다. 스쿼트 각도를 측정하기 위해 각 관성 센서(가속도 센서, 자이로 센서)의 장단점을 상호 보완 하는 상보필터 알고리즘을 사용하였고, 임상 실험을 통해 각 상보필터 계수에 따른 스쿼트 각도의 정확도를 평가하였다. 분석 결과, 최적의 상보필터 계수를 기반으로 계산된 스쿼트 각도는 측각기에서 측정한 각도와 상관 계수 0.623와 편향 오차 -5.6°로 유의한 상관관계를 보였다.

• 한국진공학회지
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• 제12권1호
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• pp.16-19
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• 2003

실온에서 p-InP (100) 위에 이온빔 증착법으로 Ni 박막을 성장하였다. Ni 박막의 이차전자방출계수(${\gamma}$)와 일함수를 결정하기 위하여 Ne, Ar, $N_2$, Xe 이온원을 사용하여 가속전압에 따른 $\gamma$를 측정하였다. 여러 가지 기체와 집속이온빔장치의 가속전압에 따른 $\gamma$결과로부터 Ni 박막의 일함 수를 결정하였다. p-InP (100) 위에 성장한 Ni 박막의 일함수는 5.8 eV ~ 5.85 eV 이었다. 실험을 통하여 얻어진 결과들은 실온에서 p-InP (100) 위에 성장한 Ni 박막의 전자적 성질에 관한 중요한 정보를 제공하고 있다.