• 제어로봇시스템학회논문지
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• 제16권10호
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• pp.927-932
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• 2010

Estimation methods of motion intention from bio-signal present challenges in man machine interaction(MMI) to offer user's command to machine without control of any devices. Measurements of meaningful bio-signals that contain the motion intention and motion estimation methods from bio-signal are important issues for accurate and safe interaction. This paper proposes a novel motion estimation sensor based on a geometrical muscle changes, and a motion estimation method using the sensor. For estimation of the motion, we measure the circumference change of the muscle which is proportional to muscle activation level using a flexible piezoelectric cable (pMAS, piezo muscle activation sensor), designed in band type. The pMAS measures variations of the cable band that originate from circumference changes of muscle bundles. Moreover, we estimate the elbow motion by applying the sensor to upper limb with least square method. The proposed sensor and prediction method are simple to use so that they can be used to motion prediction device and methods in rehabilitation and sports fields.

• 대한기계학회논문집
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• 제16권5호
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• pp.891-898
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• 1992

본 연구에서는 기존의 방식들의 단점들을 극복할 수 있고 회전하는 외팔보의 굽힘 진동 특성을 효과적으로 정확하게 예측할 수 있는 일관성 있고 간명한 방법을 제 시하는 것을 목적으로 한다. 참고문헌(9-11)에서는 회전하는 외팔보의 선형 운동방정 식을 복합 변형변수를 이용하여 구하고 있는데 이러한 동적모데링은 참고문헌(4-8)에 서와 같은 불필요한 원심력의 내재적 대입과정을 통한 2단계 운동 방정식 유도를 피할 수 있어 과정의 일관성과 간명성을 제공할 수 있음을 보였다. 본 연구에서는 이들 연구 결과에 근거하여 진동해석을 위한 방법을 제공하고 결과를 도출 분석 비교하는 것을 그 내용으로 한다.

• 국제물리치료학회지
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• 제1권2호
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• pp.162-168
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• 2010

Low back pain is a common phenomenon among the golfers. In an attempt to understand low back pain, the kinematic changes and golf swing motion analysis has been performed to focus on lumbar spine in pro. golfers. According to the swing pattern, significant variations of the lumbar joint forces and loads has related with muscles activities so the motion analysis of lumbar spine were discussed. The purpose of this study was to analyze motion of lumbar spine and it was to compare joint force during golf swing in pro. golfers. The swing motion of the subjects was tracked using a 3D motion analysis system by Motion Analysis Ltd. and SIMM software. The angle changes of lumbar spine rapidly in vx direction during the top back swing and the finish and in vy direction during the follow through and in vz direction during the down swing and the impact(Subject A). The angle changes of lumbar spine rapidly in vx direction during the top back swing and in vy direction during the down swing, the impact and the follow through and in vz direction during the down swing(Subject B). In conclusion, subject A and B both show sudden angle changes between 1st-3rd lumbar spine and 4th-5th lumbar spine during the stage from address to top back swing which caused by over upper body twisting.

• Tribology and Lubricants
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• 제18권1호
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• pp.55-60
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• 2002

In many dynamic systems, there are unwanted oscillation which may arise the reduction of performance. Especially in low sliding speed condition, the stick-slip is an important issue because it because unstable motion as well as inaccurate position control in the system. Most previous works on the stick-slip are, however, only concerned with simple modeling under the condition of constant normal force. The normal force and the amount of hydraulic oil are variable with a cylinder stroke in the telescopic boom. This paper presents the pressure variations during stick-slip with the cylinder of telescope boom. Pressure variations by stick-slip has a similar pattern to that of single mass-spring model. The stick-slip is gradually decreased by means of increased flow rate.

• Structural Engineering and Mechanics
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• 제84권1호
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• pp.85-100
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• 2022

The updated Turkish Building Earthquake Code has been significantly renovated and expanded compared to previous seismic design codes. The use of earthquake ground motion levels with different probabilities of exceedance is one of the major advances in structural mechanics with the current code. This study aims to investigate the earthquake performance of steel structure in settlements with different seismic hazards for various earthquake ground motion levels. It is focused on earthquake and structural parameters for four different ground motion levels with different probabilities of exceedance calculated according to the location of the structure by the updated Turkish Hazard Map. For this purpose, each of the seven different geographical regions of Turkey which has the same seismic zone in the previous earthquake hazard map has been considered. Earthquake parameters, horizontal design elastic spectra obtained and comparisons were made for all different ground motion levels for the seven different locations, respectively. Structural analyzes for a sample steel structure were carried out using pushover analysis by using the obtained design spectra. It has been determined that the different ground motion levels significantly affect the expected target displacements of the structure for performance criteria. It is noted that the different locations of the same earthquake zone in the previous code with the same earthquake-building parameters show significant variations due to the micro zoning properties of the updated seismic design code. In addition, the main innovations of the updated code were discussed.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2011년도 추계학술대회
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• pp.288-291
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• 2011

Video stabilization is an important image enhancement widely used in surveillance system in order to improve recognition performance. Most previous methods calculate inter-frame homography to estimate global motion. These methods are relatively slow and suffer from significant depth variations or multiple moving object. In this paper, we propose a fast and practical approach for video stabilization that selects the most reliable key frame as a reference frame to a current frame. We use optical flow to estimate global motion within an adaptively selected region of interest in static camera environment. Optimal global motion is found by probabilistic voting in the space of optical flow. Experiments show that our method can perform real-time video stabilization validated by stabilized images and remarkable reduction of mean color difference between stabilized frames.

• Structural Engineering and Mechanics
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• 제61권2호
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• pp.193-207
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• 2017

In this study, the vibration of an electrostatically actuated micro cantilever beam is analyzed in which a viscoelastic layer covers a portion of the micro beam length. This proposed model is considered as the main element of mass and pollutant micro sensors. The nonlinear motion equation is extracted by means of Hamilton principle, considering nonlinear shortening effect for Euler-Bernoulli beam. The non-linear effects of electrostatic excitation, geometry and inertia have been taken into account. The viscoelastic model is assumed as Kelvin-Voigt model. The motion equation is discretized by Galerkin approach. The linear free vibration mode shapes of non-uniform micro beam i.e. the linear mode shape of the system by considering the geometric and inertia effects of viscoelastic layer, have been employed as comparison function in the process of the motion equation discretization. The discretized equation of motion is solved by the use of multiple scale method of perturbation theory and the results are compared with the results of numerical Runge-Kutta approach. The frequency response variations for different lengths and thicknesses of the viscoelastic layer have been founded. The results indicate that if a constant volume of viscoelastic layer is to be deposited on the micro beam for mass or gas sensor applications, then a modified configuration may be found by using the analysis of this paper.

• 대한기계학회논문집
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• 제19권2호
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• pp.348-353
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• 1995

When cantilever beams rotate, their bending stiffnesses change due to the stretching caused by centrifugal inertia forces. Such phenomena result in variations of natural frequencies and mode shapes associated with constant speed rotational motions of the beams. These variations are important in many practical applications such as helicopter blades, turbomachines, and space structures. This paper presents the formulation of a set of linear equations governing the flapwise bending vibration of rotating cantilever beams. These equations can be used to provide accurate predictions of the variations of natural frequencies and mode shapes due to rotation.

• 한국생활과학회지
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• 제18권3호
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• pp.729-740
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• 2009

This study is to research on the rate of expansion or contraction according to movement of the lower body of the man their twenties using Rapid Form software. And aim of this study is to get information of ease allowance in developing slacks pattern using 3D body surface scan data through comparison with existing slacks patterns. Considering on the contraction and expansion according to movement, it need to set the more ease allowance in hip circumference than waist circumference, and the more ease allowance in back hip width than front hip width in slacks. In crotch length, the length of front crotch is revealed contraction but the length of back crotch is revealed expansion. It is desirable lowering front waist line and raising back waist line to possess ease allowance in back crotch area. The length of side seam is revealed a little expansion but the length of inseam is showed a great expansion. To develop slacks pattern of scientific approach using 3D body surface scan data, it need to analysis the rate of expansion and contraction of the lower body based on the movement, shear deformation, slip in fabrics and skin, or in fabrics and fabrics, and slip down from waist line.

• 수산해양기술연구
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• 제19권2호
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• pp.93-98
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• 1983

When detecting underwater targets using echo sounder, the echo signals varies with the angular displacement of the transducer due to ship's motion. Then, the effect of the angular which effects the capability of the echo sounder must be investigated in relation to the detection of fish concentration, particularly, the abundance estimation of fish. In this pater, as the basic research to investigate the effect of the ship's motion when estimating the fish stocks by acoustic methods, the authors was theoritically considered the variations in the values of the two way directivity function of transducer in the direction of the targets which caused by the angular motion of transducer. Here, the effects of the movement of target and ship's running are neglected. At the same time, the data was applied to estimate the angular shift of the detectable area of echo sounder due to transducer displacement. From the results analyzed, we found that the angular shift of the detectable area due to ship's motion increases both as the roll angle increases and as the beamwidth becomes narrower, varies with the depth.