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A theoretical and experimental approach was used to investigate the motion and effectiveness of a Self-Compensating Dynamic Balancer (SCDB). This is a device intended to minimize the effects of rotor imbalance and vibratory forces on a rotating system during normal operation. The basic concept of an automatic dynamic balancer has been described in many U.S. patents. The SCDB is composed of a circular disk with a groove containing massive balls and a low viscosity damping fluid. The objective of

Abstract The locomotion of a quadrupedal walking machine in an obstacle‐strewn environment is studied. The path planning of the walking machine body includes the following two features: first, the path is generated based on the Bezier curve so that its shape can be easily adjusted to avoid obstacles; second, the velocity and acceleration are assigned independently from the path generation so that the inertial terms are controllable. After the path has been generated, a gait algorithm that enable

In this paper it is shown that a fundamental technology of hybrid system combining Sagnac interferometer and FBG. Fiber optic sensor array, i.e. two sensors in the Sagnac loop was suggested. Fiber optic sensor array was fabricated in the transformer oil and external sound applied to the sensor directly using by piezoelectric. Tunable laser source was used as a light source. Applied sound frequency range is from 5kHz to 90kHz. From this experiment it is confirmed that fiber optic sensor using Sag

For the purpose of stably supplying electric power to the underwater wireless sensor, the energy harvesting technology in which a voltage is obtained by generating displacement in a piezoelectric material using flow-induced vibration is one of the most attractive research fields. The funnel type energy harvester (FTEH) with PVDF proposed in this study is an energy harvester in which the inlet has a larger cross-sectional area than the outlet and a spiral structure is inserted to generate a vorte

The self-compensating dynamic balancer (SCDB) is composed of a circular disk with a groove containing ball and a low viscosity damping fluid. The equations of motion of the rotating system with SCDB were derived by the Lagrangian method. To consider dynamic stability of the motion, perturbation equations were investigated. Based on the results of stability investigation, ball positions that result in a balanced system are stable above the critical speed with small damping (β′>3.8 case). At criti

The self-compensating dynamic balancer (SCDB) is composed of a circular disk with a groove containing ball and a low viscosity damping fluid. The equations of motion of the rotating system with SCDB were derived by the Lagrangian method. To consider dynamic stability of the motion, perturbation equations were investigated. Based on the results of stability investigation, ball positions that result in a balanced system are stable above the critical speed with small damping (β′>3.8 case). At cr

Background/Objectives: This study aimed to seek the intervention strategy of therapeutic recreation by practice analysis of support program usage for dependents of the elderly patients with dementia. Methods/Statistical analysis: The survey was conducted in 205 subjects and personal interviews were conducted in 20 subjects by random sampling. For the investigation of program participations and needs, the programs in 10 family support centers currently operating (refer to Project Report in 2014 a

Abstract The Van Allen Probes (VAPs) are the only modern National Aeronautics and Space Administration (NASA) spacecraft broadcasting real‐time data on the Earth's radiation belts for space weather operations. Since 2012, the Korea Astronomy and Space Science Institute (KASI) has contributed to the receipt of these data via a 7 m satellite‐tracking antenna and used these beacon data for space weather operations. An approximately 15 min period is required from measurement to acquisition of Level‐

Background/Objectives: This study examined the effects of serious leisure of married men on the psychological wellbeing and analyzed how leisure identity affects family function. Methods/Statistical Analysis: This study selected the population of married men among lifetime sports club members who are currently involved in activities in Daejeon city used stratum and cluster sampling and the number of the cases that were used for the final analysis was 448. The data collected through the questionn

This study was pursued to examine experience conditions for marine leisure sports of Boryung by Important-Performance Analysis on destination choice attributes of participants. For that, 425 questionnaires of participants in marine leisure sports of Boryung were sampled for Important-Performance Analysis subjects. According to results of importance and performance analysis on participants’ destination choice attributes, program safety, climate of place, natural sight, convenient transportation a

음압을 감지할 수 있는 Sagnac 간섭계 센서와 온도 및 스트레인을 측정할 수 있는 FBG센서를 결합한 새로운 형태의 하이브리드 광섬유 센서 시스템을 구축하기 위하여 입력 광원인 CW를 TLS로 대체할 필요가 있어 이에 따라 광원의 변화와 맨드릴 재료의 변화에 따른 광섬유 센서의 응답 특성 연구가 필요하게 되었다. 제작된 맨드릴 재료는 PTFE와 PTFE에 카본을 섞어 만든 두 종류로 선택하여 중공 원통형 맨드릴 겉면에 광섬유를 18 m 감아 광섬유 센서로 제작하였다. CW 광원에 대하여 음원의 입력 주파수를 1 kHz~20 kHz까지 바꾸어 가며 트랜스포머 오일이 채워진 유조에서 실험하였다. 또한 FBG와 맨드릴형 광섬유 센서를 결합한 하이브리드형 광섬유 센서 시스템을 구성하고 TLS 광원을 입사광으로 실험하였다. 실험 결과 PTFE 센서의 탐지 크기는 카본 센서 탐지 크기보다 높게 나타났고 맨드릴 재질의 탄성계수 값이 적을수록 커진다는 이론 결과와 잘 일치함을 보였다. CW 광

광섬유 사냑 간섭계는 음향 및 진동과 같은 물리적 변화량을 탐지하는 센서로 잘 개발되어 있다. 본 논문에서는 변압기유가 채워진 원통형 캐비티에 음압이 발생되었을 때 한 개의 루프내에 설치된 광섬유 배열 센서를 이용하여 음향을 탐지하였다. 서로 다른 외부 음향 주파수 <TEX>$f_1$</TEX>과 <TEX>$f_2$</TEX>를 피에조 재료를 이용하여 발생시키고 주파수는 5 kHz에서 90 kHz까지로 선정하였다. 실험 결과 광섬유 센서는 하모닉 성분인 <TEX>$f_1$</TEX>, <TEX>$f_2$</TEX>, <TEX>$2f_1$</TEX>, <TEX>$2f_2$</TEX>, <TEX>${\mid}f_1-f_2{\mid}$</TEX>, <TEX>${\mid}f_1+f_2{\mid}$</TEX>의 주파수를 탐지하였다. 제안된 광섬유 센서 배열은 변압기 내의 부분 방전으로 인한 음압과 진동과 같은 물리량을 모니터링 하는데 적용할 수 있을 것으로 판단된다. The fiber opt