• 한국소음진동공학회논문집
• /
• 제27권2호
• /
• pp.189-194
• /
• 2017

An compressor that is combined with the rotor and pneumatic technology has been researching for the performance of pressure. However, the control of operations, an accurate diagnosis and the maintenance of compressor system are limited though the simple structure of compressor and compression are advantaged to reduce the energy. In this paper, the characteristic of the compressor operating under the normal or abnormal condition is realized. and the efficient diagnosis method is proposed through feature based analysis. Also, by using the GA (genetic algorithm) and SVM (support vector machine) of machine learning, the performance of feature analysis is conducted. Different misalignment mode of learning data for compressor is evaluated using the fault simulator. Therefore, feature based analysis is conducted considering misalignment mode of the compressor and the possibility of a diagnosis of misalignment is evaluated.

• 방송공학회논문지
• /
• 제18권4호
• /
• pp.589-598
• /
• 2013

3차원 영상이 유발하는 입체 시각 피로를 이해하기 위해서는 이미 제작된 콘텐츠가 유발하는 시각피로 뿐 아니라 영상이 생성되는 촬영 시점에 영상을 결정하는 카메라 파라미터가 시각피로에 미치는 영향에 대한 연구가 필요하다. 본 연구는 카메라 파라미터인 회전 오차, 촬영 거리, 수렴 조건이 입체 시각 피로에 미치는 영향을 검증하고 모형화 하였다. 연구 결과 회전 오차, 촬영 거리, 수렴 조건이 모두 입체 시각 피로에 영향을 미치며 특히 카메라 오정렬 관련 파라미터인 회전 오차는 상대적으로 낮은 화면 시차에서 입체 시각 피로에 큰 영향을 미치는 것을 확인할 수 있었다.

• East Asian Economic Review
• /
• 제17권3호
• /
• pp.281-310
• /
• 2013

The aim of this paper is to estimate the degree of RMB misalignment from its equilibrium exchange rate by applying the Behavioral Equilibrium Exchange Rate (BEER) approach. We employ monthly data with reference to China's top 20 trading partners covering the period of 1997 to 2012. We find that the RMB was slightly overvalued before 2001 and significantly undervalued by up to 20 per cent in the end of 2006. There is evidence showing that the RMB approached to its equilibrium level from 2007 to 2008. However, the global financial crisis interrupted the trend of declining misalignment of RMB exchange rate. The RMB's total misalignment increased to around 25 per cent in the mid-2011 mainly because the RMB was re-pegged to the US dollar and some currencies of China's main trading partners depreciated during the period of crisis. More recently, the degree of RMB misalignment slightly declined since 2012 when the RMB proceeded to appreciate and China's ratio of current account surplus to GDP dropped considerably. Our findings prove that there is a trend of the RMB approaching to its equilibrium exchange rate since 2007 except for the period of crisis.

• 천문학회보
• /
• 제44권1호
• /
• pp.74.3-75
• /
• 2019

Recent Integral Field Spectroscopy (IFS) studies revealed that not only late type galaxies (LTGs) but also early type galaxies (ETGs) have various kinds of kinematic rotation. (e.g. not clearly detectable rotation, disk-like rotation, kinematically distinct core (Cappellari 06)) Among the various studies about galactic kinematics, one of the most notable anomalies is the star-gas misalignment. The gas forms stars and stars release gas through mass-loss. In this process, their angular momentum is conserved. Therefore, kinematic decoupling between stars and gas can occur due to external gas inflow or perturbation of components. There are some possible origins of misalignment: cold gas from filaments, hot gas from outer halo, interaction or merging events with galaxies and environmental effects. Misalignment, the black box from mixture of internal and external gas, can be an important keyword for understanding further about galaxies' kinematics and external processes. Using both SAMI IFS data(Sydney-AAO Multi-object Integral field spectrograph Galaxy Survey, Croom+12) and Horizon-AGN simulation(Dubois+14), we examined misaligned galaxies properties and distribution. Because the simulation has lots of galaxies at various z, we were able to study history of formation, evolution and extinction of misalignment, which was hard to be done with observation only.

• 한국자동차공학회논문집
• /
• 제12권5호
• /
• pp.118-124
• /
• 2004

To investigate the mechanics of brake squeal noise, the sound and vibration of an actual brake system was measured using a brake dynamometer. The experimental results show that disk run-out due to the misalignment of brake disk varies with brake line pressure and becomes the important factor of brake squeal noise generation. Also, it was confirmed that the frequency of the squeal noise equals to the natural frequency of the disk bending mode.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집C
• /
• pp.305-310
• /
• 2001

Within some degree of journal misalignment, maximum pressure, maximum temperature, bearing load, friction and side leakage in high-speed journal bearing operation are examined under the condition of variable density and specific heat. The results are compared with the calculation results under the conditions of constant density and specific heat, and variable density and constant specific heat. It is found that the effects of variable density and specific heat on shaft misalignment are significant in determining the load capacity of a journal bearing operating at high speed.

• 소음진동
• /
• 제10권3호
• /
• pp.401-409
• /
• 2000

Vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and magnetic origins through the motor air-gap. When a relative misalignment of rotor in the air-gap center exists on the assemblage it is considered to influence the motor system characteristics, depending on the degree of misalignment. The rotor-motor system used in a washing machine is modeled using FE-TM and a magnetic force of BLDC motor with radial rotor eccentricity is analyzed. And the transient whirl responses of a rotor system with relative misalignment in the motor air-gap are investigated considering mechanical origins and magnetic effects. Results show that rotor misalignment in the air-gap affect the vibration of the rotor-motor system.

• 한국정밀공학회지
• /
• 제21권2호
• /
• pp.130-137
• /
• 2004

A dynamic model of railway reducer is developed by the lumped parameter method. The model accounts for shafts, bearings flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of gear teeth, and bearing life are considered. Excitation forces of railway reduction are considered as the mass unbalance of the rotors, misalignment and a function of gear transmission error which comes from the modified tooth surface. A campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not the critical speed. The program which can be used to analyze and predict vibration/noise characteristics by mass unbalance, misalignment and gear transmission error of railway reduction is developed with this system model.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.632-635
• /
• 1996

Flexible parts can be deformed by the contact forces during assembly on the con to rigid parts and thus their successful assembly requires informations about their deformation as well as a misalignment between mating parts. However, because of the nonlinear and complex relationship between parts deformation and assembly reaction forces, it is difficult to acquire all required informations from only the reaction forces during assembly. In this paper, we propose a sensing system consisting of a camera and multiple mirrors for flexible parts assembly. Simulation results show that the system can be effectively used for detecting parts deformation and a misalignment between mating parts.

• 한국강구조학회 논문집
• /
• 제8권3호통권28호
• /
• pp.13-20
• /
• 1996

With the adoption of welded joints rather than bolted joints, we investigate the fatigue strength and the fatigue crack initiation of U-type trough rib and welded specimen with misalignment in a steel deck plate. The stress concentration factor of welded specimens with a misalignment is also verified by a finite element method. The main conclusions obtained from this study are as follows Experimental results of full-scaled U-type trough rib models have indicated that fatigue life depends on misalignments of welded joints in steel deck plate ; The more misalignments are, the less the fatigue life is. It has also shown that fatigue crack propagates from the welded root to the bead surface. We have also obtained the same results from both the fatigue test of welded specimens with a misalignment and the stress analysis of a finite element method.