• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.701-702
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• 2006

A novel control strategy for the induction motor drive, based on the field acceleration method, is presented. The torque is controlled through variations of the stator flux angular velocity. The stator flux is controlled by using a feed forward control scheme, with the stator flux reference vector adjusted so as to obtain the fixed rotor flux amplitude.

• Journal of Advanced Marine Engineering and Technology
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• 제31권4호
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• pp.417-424
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• 2007

This paper presents a solution that an analytical model for an induction motor and the formula of regenerative power and instantaneous torque are derived. based on the spiral vector. The torque is controlled linearly through variations of the slip angular velocity, based on the field acceleration method (FAM). And also PWM inverter fed induction motor drives is schemed to be easily a regenerative drive. The voltage source inverter fed induction motor drives that regenerative power occurs with back current type is presented, to easily controlled the feedback power and to proper the adaption of energy shaving drives. The experimental tests verify the performance of the FAM, proving that food behavior of the drive is achieved in the transient and steady state operating condition, and are discussed to save the power that regenerative power is measured at the operating acceleration or deceleration of servo system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1039-1040
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• 2007

This paper is derived a solutions for an analytical model of an induction motor and the formula of regenerative power, based on spiral vector. The torque is controlled linearity through variations of the slip angular velocity, based on the field acceleration method (FAM). And also PWM inverter fed induction motor drives is schemed to be easily a regenerative power. The experimental tests verify the performance of the FAM, proving that good behavior of the drive is achieved in the transient and steady state operating condition. and are discussed to shave the power that regenerative power is measured at the operating acceleration or deceleration of servo system.

• 스마트미디어저널
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• 제8권2호
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• pp.80-85
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• 2019

일반적으로 층간소음은 자유음장의 관점에서 데시벨(A)로 측정하고 있다. 논문에서 우리는 확산음장의 관점에서 층간진동가속도의 측정방법을 제안한다. 제안된 방법은 공동주택의 고유진동을 가속도로 측정하여 그 평균값 $20mm/s^2$를 기수의 등비수열로 나타내면, 진도계감도와 유사하게 진동체화식으로 표상할 수 있다. 이 이론을 토대로 본고는 진원지의 층간진동가속도를 HCI시스템에서 최적의 사용자 경험(UX)할 수 있도록 수식을 제시하였다.

• Structural Engineering and Mechanics
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• 제42권2호
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• pp.247-267
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• 2012

Calculating the displacements of retaining walls under seismic loads is a crucial part in optimum design of these structures and unfortunately the techniques based on active seismic pressure are not sufficient alone for an appropriate design of the wall. Using limit analysis concepts, the seismic displacements of retaining walls are studied in present research. In this regard, applying limit analysis method and upper bound theorem, a new procedure is proposed for calculating the yield acceleration, critical angle of failure wedge, and permanent displacements of retaining walls in seismic conditions for two failure mechanisms, namely sliding and sliding-rotational modes. Also, the effect of internal friction angle of soil, the friction angle between wall and soil, maximum acceleration of the earthquake and height of the wall all in the magnitude of seismic displacements has been investigated by the suggested method. Two sets of ground acceleration records related to near-field and far-field domains are employed in analyses and eventually the results obtained from the suggested method are compared with those from other techniques.

• 한국지반공학회논문집
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• 제18권2호
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• pp.39-49
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• 2002

본 연구에서는 지반-말뚝 상호작용을 고려한 동해석을 위한 해석기법의 제안과 이의 검증을 위한 진동실험을 실시하였다. 일정한 가속도에서 단독말뚝과 중심간격 2.5d(d=직경)인 2$\times$2 군말뚝의 휨모멘트 값을 측정한 결과 주파수에 관계없이 지표면으로부터 깊이 4d 미만에서 단독말뚝과 군말뚝의 휨모멘트값이 최대가 되었으며 그 값은 단독, 군말뚝 모두 일치하였으나 지표면으로부터 깊이 4d이하에서는 단독말뚝은 군말쪽에 비해 휨모멘트 값이 커지는 경향을 보였다. 진동대 실험에서 측정한 입력가속도를 수치해석에서 지진가속도로 하여 해석한 결과 단독말뚝과 군말뚝 모두 지표면으로부터 4d 미만의 상부부분에서는 실험값과 비슷한 결과를 얻었으나 군말뚝의 경우 지표면으로부터 4d 이상의 부분에서는 실험 값과는 상이한 결과를 얻었다.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2011년도 춘계학술발표대회 논문집
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• pp.21-26
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• 2011

Initial reliability prediction done by calculation would be more practical if support by evidence from customer usage profile and field failure data to improve the prediction. Thus, the consistency of the design and the product would be practically validated. In this paper, it will address rationale and method to decide on Acceleration Factor (AF) to be used in Accelerated Life Test (ALT) through usage profile and field failure. The case study of tractor transmission is used to demonstrate the method which data obtained from surveys done on farmers, field visits and field failure data from service center. By considering all the elements, it will determine more relevant AF which indicates the real use conditions of the component.

• Structural Engineering and Mechanics
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• 제75권3호
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• pp.377-387
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• 2020

Modern long-span floor system typically possesses low damping and low natural frequency, presenting a potential vibration sensitivity problem induced by human activities. Field test and numerical analysis methods are available to study this kind of problems, but would be inconvenient for design engineers. This paper proposes a simplified method to determine the acceleration amplitudes of long-span floor system subjected to walking or running load, which can be carried out manually. To theoretically analyze the acceleration response, the floor system is simplified as an anisotropic rectangular plate and the mode decomposition method is used. To facilitate the calculation of acceleration amplitude a_P, a coefficient α_wmn or α_Rmn is introduced, with the former depending on the geometry and support condition of floor system and the latter on the contact duration t_R and natural frequency. The proposed simplified method is easy for practical use and gives safe structural designs.

• Earthquakes and Structures
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• 제5권1호
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• pp.49-65
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• 2013

This article presents the statistical characteristics of elastic floor acceleration spectra that represent the peak response demand of non-structural components attached to a nonlinear supporting frame. For this purpose, a set of stiff and flexible general moment resisting frames with periods of 0.3-3.6 sec. are analyzed using forty-nine near-field strong ground motion records. Peak accelerations are derived for each single degree of freedom non-structural component, supported by the above mentioned frames, through a direct-integration time-history analysis. These accelerations are obtained by Floor Acceleration Response Spectrum (FARS) method. They are statistically analyzed in the next step to achieve a better understanding of their height-wise distributions. The factors that affect FARS values are found in the relevant state of the art. Here, they are summarized to evaluate the amplification and/or reduction of FARS values especially when the supporting structures undergo inelastic behavior. The properties of FARS values are studied in three regions: long-period, fundamental-period and short-period. Maximum elastic acceleration response of non-structural component, mounted on inelastic frames, depends on the following factors: inelasticity intensity and modal periods of supporting structure; natural period, damping ratio and location of non-structural component. The FARS values, corresponded to the modal periods of supporting structure, are strongly reduced beyond elastic domain. However, they could be amplified in the transferring period domain between the mentioned modal periods. In the next step, the amplification and/or reduction of FARS values, caused by inelastic behavior of supporting structure, are calculated. A parameter called the response acceleration reduction factor ($R_{acc}$), has been previously used for far-field earthquakes. The feasibility of extending this parameter for near-field motions is focused here, suggested repeatedly in the relevant sources. The nonlinearity of supporting structure is included in ($R_{acc}$) for better estimation of maximum non-structural component absolute acceleration demand, which is ordinarily neglected in the seismic design provisions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.361-365
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• 2006

In order to predict method of blasting vibration in ground and it's resident located around blasting field in urban area, blasting vibration characteristics were measured the vibration velocity(cm/sec), vibration acceleration($cm/sec^2$), vibration acceleration level(dB) and vibration level(dB(V)). The charged powder were used to 1.25kg and measuring sites were 25 points front 4m to 90m at the ground. The correlation of vibration velocity, vibration acceleration, vibration acceleration level and vibration level by square root scaled distance and cube root scaled distance were investigated. The correlation of PPV(peak particle velocity) velocity by SRSD(square root scaled distance) and CRSD(cube root scaled distance) was 0.85 and 0.86 and the correlation of PVS(peak vector sum) velocity by SRSD and CRSD was 0.82. Also vibration acceleration, vibration acceleration level and vibration level by SRSD and CRSD was 0.61, 0.62 and 0.82, respectively. As results, the vibration velocity and vibration level(dB(V)) was showed good correlation, but the vibration acceleration and vibration acceleration level was not showed good correlation.