• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.484-487
• /
• 2004

Symmetric directional couplers are widely used in interferometers, switches, and various signal processing devices. Recently, several optical couplers using multimode fibers were reported, but these suffer from inefficient coupling of light into a branching fiber and/or low directivity. This paper presents the measurement and analysis of loss in the connection of optical fibers via the optical directional couplers. The functionality of the device is based on the principle that is symmetrical, the power in excited mode can be unambiguously directed into one of the output channel by varying and of its parameters. In this experiment, we measure the power of loss in the optical directional coupler at various radius of curvature. Before the measurement of loss in x-coupler, we polish the contact of the fiber surface in order that light can penetrate through another port. The results show that, when the radius of curvature is increased, the loss power is decreased and also approaches of the straight line case.

• 한국디지털정책학회:학술대회논문집
• /
• 한국디지털정책학회 2005년도 춘계학술대회
• /
• pp.51-71
• /
• 2005

Performance measurement systems based on the principle that "if you can't measure it, you can't manage it" reinforce a short-term culture by focussing on tangible outputs. Instead, the focus of organisations should be on sustainable long-term performance through continuous systemic improvement. To establish and reinforce behaviours that drive systemic improvement, measurement and reporting systems need to be de designed to re-enforce work to role behaviour by managers. This paper discusses this concept and how it is being applied in practice through an ongoing action research project.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 A
• /
• pp.74-76
• /
• 1996

This measurement method described in this paper can be applied for the accurate determination for voltage and current of inverter with harmonics. The method, based on a thermal principle, relies on adaptation of the measurement thermal e.m.f to signal of inverter and comparison of AC to DC signals. The performance of the measurement system is compared with calculated results and reference power system. With this method, an accuracy of 0.1% can be achieved.

• 한국환경과학회지
• /
• 제23권11호
• /
• pp.1801-1805
• /
• 2014

Longshore current is main transportation mean causing movement of bed load and suspended particle in coastal waters, and effective measurement method and suitable equipment for shallow water coastal environment where is frequently exposed to atmosphere. Measurement equipment for longshore drift was designed and miniature model was applied to Gyeongpo beach in May and June, 2014. The equipment consists of three main elements, spheroid outer casing, spheroid inner casing, observation module equipped with GPS. Gyroscope principle was applied to observation module, and GPS receiver always can be directed upwards. Miniature models were installed along Gyeonpo beach, and it was well to track the flow of longshore current. This research described the design and function of the equipment and results of field experiments.

• 한국정밀공학회지
• /
• 제24권1호
• /
• pp.37-46
• /
• 2007

The vibration environment essentially companied by vehicle operation on the ground is determined by the shape of road surface, which is called profile. This paper focuses on development of a profile and severity measurement system for unpaved test courses. In general, the profile and severity of unpaved road is an important issue in the reliability of endurance test. In order to measure unpaved road profile and severity, it is necessary to develop a profilometer system. The developed profilometer system is composed of data processing computer, power unit, air compressor and sensors(encoder, vertical gyro and laser displacement) This paper presents the measuring system configuration, measurement principle of road profile and analysis method of road characteristics used at CPG(Changwon Proving Ground) for this purpose.

• 한국소음진동공학회논문집
• /
• 제24권9호
• /
• pp.716-723
• /
• 2014

Vibration measurement using image processing is a fully non-contact measurement method and has many application fields. The resolution of vibration data measured by image processing depends on the camera performance and is lower than that measured by accelerometers. This work discusses the method to increase resolution of vibration signal measured by image processing based on the image mosaic technique with a high-power lens. The working principle of resolution enhancement was explained theoretically and verified by several experiments. It was shown that the proposed method can measure vibrations of relatively large scale structures with increased resolutions.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
• /
• pp.145-146
• /
• 2006

Recently, the next-generation advanced flow visualization techniques such as holographic PIV, dynamic PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced measurement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. These would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is impossible for conventional measurement methods to observe most complicated nano- and bio-fluidic phenomena. In this presentation, the basic principle of these high-tech flow visualization techniques and their practical applications which cannot be resolved by conventional methods, such as blood flows in a micro-tube, in vivo analysis of micro-circulation, and flow around a living body will be introduced as a blue ocean strategy.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 춘계학술대회 논문집
• /
• pp.935-939
• /
• 2012

3D vibration measurement is achieved using one laser scanning vibrometer(LSV) and Laser scanner(LS) by moving the LSV to three arbitrarily locations from the principle that vibration analysis based on the frequency domain is independent of the vibration signal based on time domain. The proposed system has the same effect as using three sets of LSVs. It has an advantage of reducing equipment costs. Analytical approach of obtaining in-plane and out-of-plane vibration of surface is introduced using geometrical relations between three LSV coordinates and vibration measured at three different locations.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2011년도 추계학술대회 논문집
• /
• pp.527-532
• /
• 2011

Whirling vibration in severe cases may result in shaft cracking and typically gap sensors are utilized to confirm its values under the outside underwater of ship. The bending stress value causing whirling vibration on the propulsion shafting system of a 40-ton small vessel was verified by theoretical analysis and its vibration measurement. However, because of underwater condition, the accuracy for this measurement method is presumed low. In this study, the strain gauge basic principle and the bending stress calculation method are considered. The relationships are then applied for obtaining the whirling vibration of the 40-ton small vessel. As a result, a new method in estimation of whirling vibration is reached and suggested.

• International Journal of Aeronautical and Space Sciences
• /
• 제14권4호
• /
• pp.379-386
• /
• 2013

The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.