• Journal of Sensor Science and Technology
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• v.6 no.6
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• pp.466-475
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• 1997

In this paper, an implantable middle ear hearing aids using an electromagnetic transducer which consists of a tiny coil and a magnet is designed, and objective design method to implement a vibrator of the electromagnetic type transducer is proposed. Sound characteristic of the electromagnetic type vibrator is excellent but power transfer rate is lower than that of a ceramic type. To improve power transfer efficiency of system, external and inner part of a middle ear system is designed using FM transmission method. We implemented an experimental set of the designed transducer, inner part, and outer part. Then, we measured vibration characteristics of a metal strip and a temporal bone of a dead body. As the results, we confirmed the advantage of FM method and showed that designed transducer could effectively transmit vibration of amplified input sound pressure to ossicle.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.8
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• pp.526-533
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• 2008

In this study, theoretical super screen vibration analysis has been carried out to predict the dynamic characteristics of interactive waste particles. In order to approach these problems, it is necessary to have a fundamental understanding the screening process and the process of both the remaining and the passed material on a screen with several interacting screen planes based on Soldinger(1999) was discussed. Here, the vibrating screen is composed of three assemblies such as screen, wastes guide, and supported screen as shown in Fig. 1. This model is regarded vibrator as the system of screen fixed tilt plates. Then materials(or particles) of different size is to be separated by using the eccentric vibrator and classifying tilt plates. As well moisturized construction wastes is more efficient to separate than moisture-less it. In processing separate mechanism, the more materials is light, the more staying time is long. Thus much lighter construction wastes(wood, Styrofoam, etc) and heavier materials are separated by staying time delay in a super screen. The design results, separation screen were able to know that small and larger particles are conspicuous difference each motion character according to trajectory particles, and small particles raise the probability in classifying tilt plates.

• Journal of the Korean Geophysical Society
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• v.2 no.4
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• pp.251-258
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• 1999

A high-resolution seismic survey was conducted on the abandoned tidal flat in Shihwa Lake on the west coast of Korea. A portable vibrator was used as a seismic source and 217 shot gathers with 48-channel system were acquired. F-k filtering, residual static corrections and post-stack frequency filtering are found to be useful for signal enhancement. The overburden is divided into two seismic depositional units. Unit I is deposited in tidal environment characterized by parallel and high continuity reflection pattern. This unit comprises a dry layer (Unit Ia) and a wet layer (Unit Ib) having averagely 5 and 15 meters thick, respectively. Unit II unconformably overlain by Unit I exhibits discontinuity and hummocky reflection pattern, indicating complex channel-fill sediments in estuary. The maximum thickness of this unit is approximately 20 meter. Acoustic basement is considered as Precambrian granitic gneiss occurred in the surrounding area.

• The Journal of the Acoustical Society of Korea
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• v.24 no.5
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• pp.282-293
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• 2005

Sonoelastography is an ultrasound-based technique that visualizes the elastic properties of soft tissues by measuring the tissue motion generated by an externally applied vibration. In this paper. the characteristics of wave generation in soft tissues due to an acoustic vibrator are studied. The effects of modal patterns on the detectability of lesions such as tumors in senoelastography are also investigated These are accomplished by analyzing the vibration patterns calculated using theoretical equations and finite element methods in halt space, infinite plate. and finite-sized tissue. A finite-width source generates shear waves with large amplitude Propagating in specific directions. and the generation characteristics depend both on the width and frequency of the vibrator. as well as the distance from it. It is shown in a finite-sized tissue that the lesion detection in displacement images is quit dependent on the modal patterns inside tissue. In contrast it Is also found that the lesion detectability in strain images is less dependent on the modal Patterns and is much better than that in displacement images.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.296-302
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• 2019

In this study, a basic durability assessment was performed by selecting the main part of a trial product of a shale shaker, which is one of components for a mud circular system. For a preliminary durability assessment, it was assumed that the lifetime of the bearing for the vibrator motor and the stiffness of the support spring are affected by the vibration when the motor operates continuously. In the case of the motor, the initial p-p level was 0.72 g, but after 100 hours of operation, the p-p level was rapidly increased to 1.26 g. Bearing defects could be estimated through ball defect frequency analysis. In the case of the spring, the stiffness of the spring was reduced by approximately 3.78% at the end of 2,000 hours of the fatigue-durability test by applying excitation conditions to shale shaker body. In the future, we will analyze the influence of the particle removal efficiency of the shale shaker.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.465-469
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• 2019

In this paper, the design of BLDC (brushless direct current) motors based on torque and back-EMF equations was carried out to assess the application of the motor in concrete vibrators. The air gap flux density of the motor is an important parameter because the length of the motor and the size of the diameter are given. The air gap magnetic flux density was calculated through a simplified magnetic circuit, and basic design of the shape and dimensions of the motor were then determined by carrying out experiments based on torque, back-EMF, and air magnetic flux density equations. After setting the outer and inner diameters, stack lengths, and rated speed of the motor, a detailed design was performed by simulations using the finite element method by designating the diameter and thickness of the motor as the key parameters. The final design to satisfy the target torque and the lowest THD (Total Harmonic Distortion) was carried out along with a simulation.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.191-200
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• 2021

Purpose : Chronic ankle instability can lead to problems in balance and gait due to weakness of the ankle muscles and decreased proprioceptive sensation. Balance training that stimulates proprioceptors is necessary to improve ankle stability. We aimed to compare the effects of unstable support balance exercises using whole body sonic vibration and an aero-step (TOGU) on proprioception and balance in individuals with unilateral functional ankle instability. Methods : Thirty-six participants with unilateral functional ankle instability were randomly recruited and divided into two groups (group 1 = sonic whole body vibration, group 2= TOGU). Individuals in each group participated in training for 5 weeks, 40 minutes per session, 5 times per week, and performed weight-bearing exercises in five postures on different unstable support surfaces. Proprioception was measured by digital inclinometer (Dualer IQ), and balance was measured by force platform (Biodex balance system). Results : Significant differences were observed in proprioception before and after intervention within both group (p<.05). Significant differences were also observed in the balance index before and after intervention within both groups (p<.05). Conclusion : As a result of this study, it is suggested that for individuals with ankle instability, unstable support surface training using a whole body sonic vibrator and TOGU can have a positive effects on proprioception and balance ability.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.463-466
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• 2006

최근 전자기기에서 시각 및 청각과 함께 촉각 디스플레이가 정보를 출력하는 중요한 수단으로 부각되고 있다. 본 논문에서는 촉각 정보 출력을 위한 소형진동촉각(vibrotactile) 디스플레이 모듈을 개발하였다. 개발한 모듈은 주파수와 진폭을 독립적으로 조절할 수 있으며 핀이 직접 피부에 자극을 주기 때문에 몸체 전체가 떨리는 기존의 진동모터보다 정밀하고 다양한 촉각 표현을 할 수 있다. 또한 고전압을 이용하는 Piezo 방식과 달리 낮은 전력으로 동작이 가능하여 휴대장치에 직접 장착할 수 있는 장점을 가지고 있다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.369-372
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• 2000

PZT 세라믹 트랜스듀서와 같은 압전 세라믹 진동자를 사용하는데 있어서 품질계수(quality factor)를 제어할 수 있다는 것은 전기-기계 결합계수나 삽입손실 등을 개선 할 수 있으므로 매우 유용한 것이다 본 연구에서는 압전 진동자의 품질계수를 제어하는 방법으로써 압전 진동자의 제동용량과 저항성분을 전기적으로 상쇄시킬 수 있는 부임피던스 변환회로(negative impedance converter circuit)를 적용하였다. 그 결과 부임피던스 변환회로를 적용하지 않은 경우에 비해 압전 진동자의 품질계수가 수십 배정도 까지 제어됨을 실험으로 확인하였다.

• Journal of the Semiconductor & Display Technology
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• v.14 no.1
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• pp.31-37
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• 2015

This paper is on the design and manufacturing of vibration tester (shaker) for experiments about effects on the performance of semiconductor chips and Li-ion batteries by vibration. Shaker in the market are quite expensive, it is difficult for basic researchers to contact. In this study, in order to improve this, we designed and manufactured with an entry-level into mass production possible approaches in terms of performance required to a minimum. The shaker system is operated by Matlab and LabView. The target performances are 200Hz frequency and 5% error, and these were satisfied.