• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.302-307
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• 1990

An automatic visual classification system is introduced which provides for measuring the length and diameter of coilform cores and dividing them into 5 different classes in terms of how far their length be from the desired length. This task is fully automated by controlling two STEP motors and by using image processing techniques. The classification procedure is broken into three logical parts. Fist, cores in the form of randomly stacked bundle are lined up one by one so as to be well captured by a cameras. The second part involves capturing core image. Then, it enters the measuring process. Finally, this machine would retain all tire information relating to the length. According to the final result, cores are sent to the corresponding bin. This considerably simplifies the selecting task and facilitates a greatly improved reliability in precision. The average classifying capability about 2 pieces per second.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.4
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• pp.539-549
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• 1993

The purpose of this study was to find out the moving fitness and slit length of tight skirt in relation to its length & silhouette. Five kinds of length, micro mini, mini, natural line, medi and maxi, and two kinds of siihuette, slim & straight-a total of ten tight skirts-were investigated. Ten college students were chosen for this experiment. The moving fitness was tested by measuring the step length, step width and step angle in the case of walking on the flat and going up the stairway & bus stair. The slit length was tested by measuring the back slit length needed in the case of going up stairway & bus stair. Data were analyzed with use of SAS pakage. The statistics were based on average, standard diviation, two-way ANOVA, Pearson's correlation and multiple regression analysis. The main results were as follows. 1. There was significant difference in the moving fitness according to length & silhouette of tight skirt. The moving fitness of slim type was lower than that of straight type and the longer the skirt length was, the lower the moving fitness was. The significance appeared particularly in the case of going up the bus stair. 2. There was significant difference in the skirt length obove slit accorting to length & silhouette of tight skirt. The skirt length obove slit of slim type was shorter than that of straight type. The longer skirt length was, the longer it was from micro mini to natural line, that of medi skirt was shorter or a little longer than that of natural line skirt and there was little change from medi skirt to maxi skirt.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.547-550
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• 2005

Gauge blocks are the most widely used material measure in length field in industry. The gauge block interferometer, which is the gauge block measuring system, comprises Twyman-Green type interferometer optics and light sources having precisely known wavelengths. This paper describes the work done for advancing the measurement system and automating the measurement process. The advancing of the system was done mainly by exchanging the spectral lamp with the frequency stabilized lasers, and the automation of measurement was achieved by modifying the hardware and developing the automatic measuring software. As the results of this work, the contrast of interferometric fringes of gauge blocks longer than 100 mm s enhanced about 20 times, and the measurement time has reduced down to 50% by automation.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.167-173
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• 2004

The heterodyne He-Ne laser interferometer is the most widely used sensing unit to measure the position error. It measures the positioning error from the displacement of a moving reflector in terms of the wave length. But, the wave length is affected by the variation of atmospheric temperature. Temperature variation of 1$^\circ C$ results in the measuring error of 1ppm. In this paper, for measuring more accurately the position error of the ultra precision stage, the refractive index compensation method is introduced. The wave length of the laser interferometer is compensated using the simultaneously measured room temperature variations in the method. In order to investigate the limit of compensation, the stationary test against two fixed reflectors mounted on the zerodur$\circledR$ plate is performed firstly. From the experiment, it is confirmed that the measuring error of the laser interferometer can be improved from 0.34${\mu}m$ to 0.11${\mu}m$ by the application of the method. Secondly, for the verification of the compensating effect, it is applied to estimate the positioning accuracy of an ultra precision aerostatic stage. Two times of the refractive index compensation are performed to acquire the positioning error of the stage from the initially measured data, that is, to the initially measured positioning error and to the measured positioning error profile after the NC compensation. Although the positioning error of an aerostatic stage cannot be clarified perfectly, it is known that by the compensation method, the measuring error by the laser interferometer can be improved to within 0.1${\mu}m$.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.3
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• pp.47-54
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• 2009

In the manufacturing industry, there has been a significant increase in the use of coordinate measuring machines(CMM). In this paper, the sources of CMM measurement performance are discussed. The effects of workpiece position, length and orientation are analyzed by using the design of experiments. Both a fractional factorial design and a factorial design are employed to conduct the experimental study. The analysis of variance is performed to determine the significance of factors in the experiment and regression analysis is applied to make the measurement approximate model. The results show that position along the Z axis, length and orientation affect the CMM measurement performance.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.79-82
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• 2002

Three-dimensional pipe flows with elbows and tees for few different pipe fittings are calculated to estimate the effect of swirling flow on measuring accuracy of orifice flow meter. It is evaluated how the pressure difference across the orifice is dependent on the length of upstream straight pipe in a branch and how swirl intensity, swirl angel and axial velocity distribution affect the measuring error of orifice flowmeter. From the results, it is found that, regardless of flow rate specified in this calculation, the effect of the straight pipe length can be neglected for the lengths larger than thirty diameters although there still remain significant swirl at the orifice

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.67-75
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• 2006

In this paper, the compensation of ultrasonic scattering on interface crack depending on thickness variations of A1/Epoxy bonded dissimilar components was applied to improve measuring accuracy by using ultrasonic attenuation coefficient. The optimum conditions of theoretical value and experimental measuring accuracy by the ultrasonic method in A1/Epoxy bonded dissimilar components have been investigated. From the experimental results, the measurement method of interfacial crack lengths by using ultrasonic attenuation coefficient was proposed and discussed. After the ultrasonic scattering compensation depending on thickness variations of bonded dissimilar components was carried out, the measuring accuracy of interfacial crack length was improved by 5%.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.131-141
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• 1989

This study was designed to investigate the fitness of stock tray in Korean adults. 107 dental students (male: 87, female: 20) who have normal occlusion and symmetric facial fom were selected. The upper and lower stock tray (Osungtray, Osung Co., Korea) fit with dental arch were selected for taking irreversible hydrocolloid impression. The author measured the thickness of impression material about two items, that is, width and length on the flange of stock tray. Several measuring points on the dental arches and palatal area were checked with Goldman Fox prove (Hu-Friedy, U.S.A.). The obtained results were as follows: 1. The width of impression material on buccal flange of upper and lower trays were narrower than any other measuring point, but the thickness of impression material on the palatal area of upper stock tray was the widest of all measuring points. 2. The length on buccal flange of lower stock tray was shorter, but the length on tray flange of lower stock tray at lingual frenum area was longer. 3. On upper dental arch, the upper extra-large tray was used in 53% of subjects, but upper small tray was not used. 4. On lower dental arch, the large tray was used in 55% of subjects. 5. There was not adequate tray on upper dental arch in 4 subjects.

• Journal of Educational Research in Mathematics
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• v.18 no.2
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• pp.157-177
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• 2008

This paper provides a description of the process in development of textbook unit on measuring length for second grade in elementary school according to action research methodology. The teaching unit development has been done based on the new national mathematics curriculum released in 2006. Mathematical communication and positive attitude toward mathematics are highly emphasized in the new curriculum. These new foci have been analysed through literature review and interviews with two incumbent teachers to be respected in the unit in an appropriate way. Three stages of development with different ways of organizing contents and different problem contexts were reported in the paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.6
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• pp.35-41
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• 2011

In order to design effectively the grounding system, it is very important to determine the optimum soil resistivity at the desired location of the connection to earth. This paper deals with the reasonable methods of measuring the soil resistivity where grounding electrodes are buried. The soil resistivity at three test sites with different resistivity of soil were measured as functions of the spacing between the test probes in the Wenner's four-point method and the length of test ground rod in the three-point method. In the case of the three-point method, the length of test ground rod of 2-10[m] in length was appropriate in two-layered soil structure. In the length range of 2-10[m], the results measured by the three-point method using the test ground rod with the length corresponding to the spacing between the test probes of the Wenner's four-point method are in good agreement with the data obtained from the Wenner's four-point method.