• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.625-627
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• 2002

High precision voltages. currents. power factor and electrical power measurements wide range of frequency can be achieved by using the thermo-elements (thermal converters). This paper describes the development wattmeter. based on a thermal principle. The instrument has been performed measurement in the range of currents from 0 to 50 A, voltages up to 600 V, power factor 0.5. 1 and frequencies from 45 Hz to 3 kHz. The thermal converters with two heater are used in the functional element of the wattmeter.

• Tribology and Lubricants
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• v.18 no.4
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• pp.285-290
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• 2002

Integrated condition monitoring is required to monitor effectively the machine conditions since machine failures could not be monitored accurately by any single measurement parameter. Application of various condition monitoring techniques is therefore preferred in many cases in order to diagnosis the machine condition. However it inevitably requires lots of maintenance cost and sometimes it could be proved to over-maintenance unnecessarily. This could happen especially when one measurement parameter closely correlates to another. Therefore correlation analysis of various monitoring parameters has to be performed to improve the reliability of diagnosis. In this work, Pearson correlation coefficient was used to analyze the correlation between condition monitoring parameters of an over-loaded machine system where the vibration, wear and temperature were monitored simultaneously. The result showed that Pearson correlation coefficient could be regarded as a good measure for evaluating the availability of condition monitoring technology.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.18 no.1
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• pp.1-10
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• 2012

Thoracic kyphosis is occasionally used to describe someone with accentuated thoracic curvature, hyperkyphosis is preferred since kyphosis itself refers to the normal sagittal angle of thoracic curvature. The angle of thoracic kyphosis tends to increase with age resulting in hyperkyphosis in some individuals. The persons who suffer from hyperkyphosis are at increased risk for a variety of adverse health outcomes that include musculoskeletal alteration, physical functional limitations, poor quality of life, falls, and even earlier mortality. Hyperkyphosis may develop from vertebral fractures, degenerative disc disease, either muscle weakness, decreased mobility and sensory deficits. The gold-standard orthopaedic technique for assessment of thoracic kyphosis is standing lateral spine radiographs. Other clinical measures are Debrunner kyphometer, inclinometer, flexicurve ruler, arcometer, flexible electrogoniometer and spinal mouse.

• Journal of the Korean Statistical Society
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• v.14 no.2
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• pp.63-75
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• 1985

This paper considers a statistical calibration problem in which the standard as wel as the nonstandard measurement is subject to error. Since the classicla approach cannot handle this situation properly, a functional relationship model with additional feature of prediction is proposed. For the analysis of the problem four different approaches-two estimation techniques (ordinary and grouping least squares) combined with two prediction methods (classical and inverse prediction)-are considered. By Monte Carlo simulation the perromance of each approach is assessed in term of the probability of concentration. The simulation results indicate that the ordinary least squares with inverse prediction is generally preferred in interpolation while the grouping least squares with classical prediction turns out to be better in extrapolation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.36-40
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• 2013

Recently, electronic equipments become smaller, more functional, and more complex than before. As these trends, MLC(multi-layer ceramic) circuit has been emerged to a promising technology in semiconductor inspection industry. Especially, multi-layer ceramic which is consisted of many fine-pitch multi-hole is used to produce a semiconductor inspection unit. The hole is processed by UV laser. But, working conditions are changed all the time. Therefore real time measurement of fine-pitch multi-hole is very important method for ensuring performance. In this paper we found the best method for illuminating and auto focusing. And, we verified our equipment.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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• pp.51-54
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• 2005

In this work, the attempt has been made to investigate the morphology of self-assembled dipyridinium dithioacetate on Au(111) substrate by Scanning Tunneling Microscopy(STM). Also, we measured electrical properties(I-V) using Scanning Tunneling Spectroscopy(STS). Sample used in this experiment is dipyridinium dithioacetate, which contains thiol functional group, this structure that can be self-assembled easily to Au(111) substrate. The self-assembly procedure was used for two different concentrations, 0.5 mM/ml and 1 mM/ml. Dilute density of sample by 0.5 mM/ml, 1 mM/ml and observed dipyridinium dithioacetate's image by STM after self-assembled on Au(111) substrate. The structure of STM tip-SAMs-Au(111) substrate has been used measurement for electrical properties(I-V) using STS. The current-voltage(I-V) measurement result, observed negative differential resistance(NDR) properties.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.260-263
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• 2001

This paper is to develop the sensing system for opening-force measurement such as O-Ring muscular meridian. We designed to overcome the functional limit that the conventional force-sensor can measure just the closing-force. Therefore, the new sensor can meet a variety of application as well as O-Ring test. The structure of the new sensor is an actuator-type system using an electromagnet. That is made up of mechanical system, electromagnet, current transformer and computer interface circuit. Driving software and user interface program of the new sensor system also is explained in this paper.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1510-1519
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• 1994

It is important to understand the friction characteristics between piston-ring assembly and cylinder wall for the friction loss reduction as well as the solution of problem such as scuffing wear and oil consumption. A new system was developed for the piston-ring assembly friction force measurement. This system was applied to the friction force measurement to find its functional relationship with variables such as engine speed, oil viscosity, and engine load. The friction mean effective pressure(fmep) was found to have a linear relationship with$(\vpsilon{U})^{0.42}$ under motering and with$(\vpsilon{U})^{0.45}$ under firing operations, where $\vpsilon$ is the kinematic oil viscosity and U is mean piston speed.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.235-239
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• 1992

The paper describes an approach for estimating unsteady flow rate through oil hydraulic pipelines and components in real time. Recently we have proposed following three unsteady flow rate measurement approaches; RIFM, QIFM and TPFM, in which hydraulic pipeline dynamics are made use of. In this paper, we firstly propose new approaches, i.e, an interpolation and an extrapolation methods in combination with RIFM and TPFM. In the interpolation method, unsteady flow rate at the arbitrary internal location along the pipeline between two points for measuring the two point pressure can be estimated. In this paper, the accuracy and dynamic response of interpolation method are mainly experimentally investigated in detail.

• Journal of Power System Engineering
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• v.13 no.1
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• pp.65-71
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• 2009

To address the need for new intelligent sensing, this paper introduces nano sensors made of carbon nanotube (CNT) composites and presents their preliminary experiments. Having smart material properties such as piezoresistivity, chemical and bio selectivity, the nano composite can be used as smart electrodes of the nano sensors. The nano composite sensor can detect structural deterioration, chemical contamination and bio signal by means of its impedance measurement (resistance and capacitance). For a structural application, the change of impedance shows specific patterns depending on the structural deterioration and this characteristic is available for an in-situ multi-functional sensor, which can simultaneously detect multi symptoms of the structure. This study is anticipated to develop a new nano sensor detecting multiple symptoms in structural, chemical and bio applications with simple electric circuits.