• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.1
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• pp.33-42
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• 1996

The high coherence of laser beam has made it possible to observe interference effects even in the light scattered from rough surfaces. That's why, when object with a scattering surface is illuminated with laser light, we do see a speckled appearance due to random interference. This sort of unique property of laser speckle has bruht into existence the new noncontaciting techniques such as speckle metrology method of measuring deformation, displacement, and vibration etc of objects with high optical sensitivity. The measurable range of speckle metrology especially used to measure in -plane information, however, is limited by some factors, the so-called strain, rotation tilt of surface and out of displacement perpendicular to the plane of analysis This restrictions severly limits the measurable range of speckle metrology by causing the decorrelation of speckle patterns. It is the purpose of this paper to give a survey on the measurable limitation of speckle photography method that is one of speckle metrology. Namely we will discuss the mutual relationships and problems of each limitations adding the restriction on the largest and smallest displacement measurable with speckle methods.

• Journal of the Chungcheong Mathematical Society
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• v.3 no.1
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• pp.33-40
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• 1990

We prove that if a $weak^*$-measurable function f defined on a finite measure space into a dual Banach space is separable-like, then for every measurable set E, the $weak^*$ core of f over E is the $weak^*$ convex closed hull of the $weak^*$ essential range of f over E.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.2
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• pp.106-111
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• 2011

In this paper, assumed mode method on Euler beam theory is employed and signal distortion is considered to obtain the performances of a MEMS accelerometer which are a sensitivity and measurable frequency range(MFR). Not only the sensitivities and MFR but also the variations of dynamic responses and natural frequencies of the MEMS accelerometer are investigated for several sets of beam properties such as length, width, thickness and Young's modulus. It is stated that the variations of beam properties significantly influence the performances of the MEMS accelerometer and the relationship between sensitivities and MFR is inversely proportional to each other.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.158-161
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• 1995

A new laser diode range-finding speedometer is proposed, which is modulated by a pair of positive and negative triangular pulse current superimposed on a dc current. Since a target velocity is directly obtained form a pure Doppler beat frequency measured during the non-modulation period, the new sensor is free from the difficulties due to the critical velocity encountered in the previous sensor. Furthermore, the different amplitude of the two triangular pluses are so adjusted that the measurable range using only one laser head is greatly expanded to 10cm through 150cm, which is about two times that of the previous sensor. The measurement accuracy for velocity of .+-.6mm/s through .+-.20mm/s and for range is about 1%, and 2%, respectively. Because the new sensor can be operated automatically using a microcomputer, it will be useful for application of a 3-D range image measurement of a slowly moving object.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.92-98
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• 2010

The capacitive sensor has a simple structure, compact size and low cost, but a small dynamic range. The small range is caused by use of gap variation. If the sensor takes area variation type with one plate moving horizontally, it can have a large measurable range. While the area variation has relatively low sensitivity, some studies have found methods to improve the sensitivity. Even though the methods are effective, parameters of the results are limited and 2 dimensional. This study provides more practical and 3 dimensional analysis and suggests relations between parameters. Using the results, the optimized design parameters of a high dynamic range capacitive sensor can be found.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.394-398
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• 1992

The measurable speed range of the self-mixing type semiconductor laser range finder has been greatly improved by employing a new processing circuit. Using this range finder as an external finder of a single lens reflex (SLR) autofocus (AF) camera, some clear photographs of an object moving at a medium speed of 20 mm/s is obtained.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2430-2432
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• 1998

Generally, in the best-known Pulse-type type and Frequency Modulated Continuous Wave(FM/CW)-type RF range measurement systems, the nearest measurable distance between antenna of system and targets is limited to several tens of meters. Moreover, in case of high-speed targets it is more difficult to measure the distance precisely. In this paper we design our own RF(X-band) range(up to 15 meters) measurement system usi code correlation for high- speed targets. It 0 the correlation value between transmitting receiving PN (Pseudo -Noise) codes. So we determine the distance between antenna of s and targets using this correlation value. We fabricated it using MIC techniques and experimental results show that the proposed syste fully qualified for a short range measurement syste

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.396-400
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• 2012

We introduce a combined technique and the mathematical description for distance measurements using a femtosecond pulse laser in a long range and a fine resolution. For distance measurements, the maximum measurable range can be extended by combining measurement results from several different methods while requiring relationships between the different measurement uncertainties and unambiguity ranges. This paper briefly explains why the uncertainty of a rough measurement technique (RMT) should be, at least, smaller than the half unambiguity range of a fine measurement technique (FMT) in order to combine a FMT with a RMT. Further discussions about the total measurement range, resolution, and uncertainty for various optical measurement techniques are also discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.53-58
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• 2011

Ultra-precision miniaturized machine tools essential for manufacturing accurate machine components in micro/meso-scale have been developed. To realize high accuracy using mMTs, geometric errors, which are considered as the main sources of inaccuracy should be identified and compensated. The conventional systems for measuring geometric errors, such as a laser interferometer, can measure only one geometric error in a single setup and they involve complicated measurement procedures. A measurement system using PSDs is a promising alternative but the measurable range of such systems is limited to the active range of the PSDs. The proposed measurement system using PSDs can overcome the limit of small measurable range. Further, the mounting errors that could occur during set-up process can be avoided. In this paper, an algorithm corresponding to the system was analyzed and experiments were carried out.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.184-184
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• 2012

Recently, as a result of the application of large and multi-blade propellers with high efficiency for large vessels, the vertical bending stiffness of propulsion shafting system tends to be declined. For some specific vessels, the shaft arrangement leads to the forward stern tube bearing to be omitted, decreasing vertical bending stiffness. In this respect, decreased vertical bending stiffness causes the problem which is the blade order resonance frequency to be placed within the operational range of propulsion shafting system. To verify whirling vibration, the measurement should be carried out covering the range of MCR, however, the range is un-measurable. To resolve the measurement issue, this study shows the measuring method and the estimating method of whiling vibration by using resonance frequency of sub harmonic.