• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1054-1058
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• 1995

There have been many research works for the indirect cutting force measurement in machining process, which deal with the case of one-axis cutting process. In multi-axis cutting process, the main difficulties to estimate the cutting forces occur when the feed direction is reversed. This paper presents the indirect cutting force measurement method in contour NC milling processes by using current signals of servo motors. An artificial neural network (ANN) system are suggested. An artificial neural network(ANN) system is also implemented with a training set of experimental cutting data to measure cutting force indirectly. The input variables of the ANN system are the motor currents and the feedrates of x and y-axis servo motors, and output variable is the cutting force of each axis. A series of experimental works on the circular interpolated contour milling process with the path of a complete circle has been performed. It is concluded that by comparing the ANN system with a dynamometer measuring cutting force directil, the ANN system has a good performance.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.55-61
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• 2011

This paper presents bubble wake measurement results generated by the planing hull. The bubble was generated by SNAME TMB model(No. 4876) with hard chine at the CWC(Circulating Water Channel). ABS(Acoustic Bubble Spectrometer) was used to measure bubble wake measurement. The manufactured model is one meter in length and uniform velocity to generate the bubble at CWC is 3m/s, relatively higher speed than conventional hull form. Measurements were performed successfully and measured results show well the general characteristics of bubble wake generated by planing hull. Furthermore, experimental equations are proposed for the practical use.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.29-35
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• 2000

The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to guide vane region within diffuser pump. Various different kinds of rotational velocity were selected as experimental condition. Optimized cross correlation identification to obtain velocity vectors is implemented with direct calculation of correlation coefficients. Fine optical setup concerned with PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. Variable flow pattern are represented quantitatively at the stator region.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.63.2-63
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• 2001

It is necessary to distance measurement to detect about obstacles and front vehicles to autonomously navigate. In this paper, we propose an algorithm using stereo vision. It is as follows this algorithm´s procedure. First, It has detected a front vehicle´s common edges from left and right images by image processing. We select number plate of a front vehicle as edges. Then, we estimate distance by triangle measurement method after stereomatching using corner points of the plate´s edges as feature-based points. Experimental results show errors and values compand with experimental ones after set up distance between vehicles in advance.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.391-396
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• 2000

The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to guide vane region within a diffuser pump. Various different kinds of clearance were selected as experimental conditions. Optimized cross correlation identification to obtain velocity vectors was implemented with direct calculation of correlation coefficients. Fine optical setup important in PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. Various flow patterns are represented quantitatively at the stator passages.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.340-345
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• 2003

In this paper, the ultrasonic attenuation coefficient was measured by variation of crack length for double-cantilever beam(DCB) specimen. The energy release rate, G, was obtained by the experimental measurement of compliance. The experimental results represents that the relation between crack length for the ultrasonic attenuation coefficient and energy release rate is increased proportionally. From the results of experiments, the measurement method of crack length by the ultrasonic attenuation coefficient was proposed and discussed.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.161-166
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• 2002

The resent experimental study is focused on the application of multi-point simultaneous measurement by PIV Particle Image Velocimetry) to guide vane region within diffuser pump. Various different kinds of rotational veto ity and changing clearance between Guide Vane and Impeller were selected as experimental condition. Optimized ross correlation identification to obtain velocity vectors is implemented with direct calculation of correlation coeffi cients. Fine optical setup concerned with PW performance is arranged for the accurate PW measurement of high peed complex flow. Variable flow pattern are represented quantitatively at the stator region.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1271-1280
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• 2000

A sensor placement technique to identify structural parameter was developed. Experimental results must be acquired to identify unknown dynamic characteristics of a targeting structure for the comparison between analytical model and real structure. If the experimental environment was not equipped itself properly, it can be happened that some valuable information are distorted or ill-condition can be occurred. In this work the index to determine exciting points was derived from the criterion of maximizing parameter sensitivity matrix and that to choose measurement points was from that of preserving the invariant of sensitivity matrix. This idea was applied to a compressor hull structure to verify its performance. The result shows that the selection of measurement and excitation points using suggested criteria improve the ill-conditioning problem of inverse type problems such , as model updating.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.5
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• pp.415-423
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• 2002

An experimental study using a psychrometric calorimeter was conducted to investigate the temperature and pressure mea surement errors permitted for determining cooling capacity of an air conditioner. First, the instrument calibration was made in accordance with the related test methods and guidelines in order to accurately evaluate basic performance (cooling capacity and airs flow rate). Secondly, a parametric study was performed to examine the effect of measurement error involved if temperature and pressure measuring instruments on the cooling capacity calculation. From the results, it was found that the degree of accuracy for both temperature and pressure measurements played an important role on the error occurring in the determination of cooling capacity and needed to be maintained within a certain value to guarantee required accuracy of cooling capacity.

• The KSFM Journal of Fluid Machinery
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• v.2 no.1 s.2
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• pp.35-42
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• 1999

The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to rotor-stater region within centrifugal turbine pump. Six different kinds of rpm(120, 500, 1000, 1500, 2000 and 2500) are selected as experimental condition. Optimized cross correlation identification to obtain velocity vectors is implemented with direct calculation of correlation coefficients. Fine optical setup concerned with PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. The instantaneous and time-mean velocity distribution and velocity profile are represented quantitatively at the rotor and stator region.