• Journal of Applied Reliability
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• v.15 no.1
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• pp.60-66
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• 2015

In this paper, The infrastructure case for reproduction or analysis of the mechanism on the fire or the electrics shock of the electrical appliances is proposed. The various electrical appliances(Washing machine, Ballast, Electric heaters, Electronic switches, Mobile phone chargers) used in the home can be tested on the high voltage and over current test through the implementation of the infrastructure. The electrical tests of fire and electric shock consists of the high voltage of maximum 5000 V and over current test of 3 steps(90 A, 60 A, 40 A) and noise test. The mechanism of the fire and the electric shock tests reproduced are analyzed through the monitoring system and the oscilloscope. The electronics manufacturers can prevent accidents through the tests of the electronics factor reproduced and the analysis of the infrastructure designed.

• Geomechanics and Engineering
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• v.12 no.6
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• pp.883-898
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• 2017

To eliminate the holding and gluing problems making the direct tensile strength test hard to be applied, a new method of testing specimens prepared using lathe machine to make the dog bone shape is assessed whether it could be applied to determine accurate direct tensile strength values of rock materials. A series of numerical modelling analyses was performed using finite element method to investigate the effect of different specimen and steel holder geometries. In addition to numerical modelling study, a series of direct tensile strength tests was performed on three different groups of rock materials and a rock-like cemented material to compare the results with those obtained from the finite element analyses. A proper physical property of the lathed specimens was suggested and ideal failure of the dog bone shaped specimens was determined according to the results obtained from this study.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.6 s.261
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• pp.644-650
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• 2007

Mechanical property evaluation of micrometer-sized structures is necessary to help design reliable microelectromechanical systems(MEMS) devices. Most material properties are known to exhibit dependence on specimen size and such properties of microscale structures are not well characterized. This paper describes techniques developed for tensile testing of thin film used in MEMS. Epi-polycrystalline silicon is currently the most widely used material, and its tensile strength has been measured as 1.52GPa. We have developed a tensile testing machine for testing microscale specimen using electro-magnetic actuator. The field magnet and the moving coil taken from an audio-speaker were utilized as the components of the actuator. Structure of specimen was designed and manufactured for easy handling and alignment. In addition to the static tensile tests, it is described that new techniques and procedures can be adopted for high cycle fatigue test of a thin film.

• Transactions of Materials Processing
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• v.14 no.6 s.78
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• pp.509-513
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• 2005

This paper is concerned with manufacturing technology of thin foil tensile specimen using CIP(Cold Isostatic Press) and measurement of precision mechanical properties using micro tensile testing. We can get a burr free micro metallic thin foil specimen using this technology. For testing mechanical property of this micro thin foil, we use a nano scale material testing machine that was developed by KITECH. In this paper, micro tensile specimens of nickel and copper thin foil are fabricated with CIP and precision mechanical properties of these materials could be measured. We will expect precision mechanical property of micro/nano material and component.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.793-794
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.529-530
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• 2011

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.15-23
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• 2005

For reliability assessment for machine tools, failure mode analyses by two viewpoints were studied in this paper. First, this study developed the reliability data analysis program, which searches f3r optimal failure distribution like failure rate or MTBF(Mean Time Between Failure) using failure data and reliability test data of mechanical parts in the web. Moreover, this data analysis program saves both failure data or reliability data and their failure rate or MTBF for database establishment. Second, this paper conducted failure mode analysis through such performance tests as circular movement test and vibration testing for machine tools when reliability data is not available. A developed web-based analysis program shows correlations between failure mode and performance test result and also accumulates all the data. These kinds of data analysis programs and stored data furnish valuable information for improving the reliability of mechanical system.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.294-300
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• 2021

The current society relies upon social media on an everyday basis, which contributes to finding which of the following supervised machine learning algorithms used in sentiment analysis have higher accuracy in detecting Malay internet slang and short forms which can be offensive to a person. This paper is to determine which of the algorithms chosen in supervised machine learning with higher accuracy in detecting internet slang and short forms. To analyze the results of the supervised machine learning classifiers, we have chosen two types of datasets, one is political topic-based, and another same set but is mixed with 50 tweets per targeted keyword. The datasets are then manually labelled positive and negative, before separating the 275 tweets into training and testing sets. Naïve Bayes and Random Forest classifiers are then analyzed and evaluated from their performances. Our experiment results show that Random Forest is a better classifier compared to Naïve Bayes.

• International Journal of Quality Innovation
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• v.5 no.1
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• pp.68-84
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• 2004

The measured values of a same object should remain constant regardless of the object's position in the image. In other words, its measured values should not vary as its position in the image changes. However, lens' image distortion, heterogeneous light source, varied angle between the measuring apparatus and the object, and different surroundings where the testing is set up will all cause variation in the measurement of the object when the object's position in the image changes. This research attempts to compensate the machine vision image distortion caused by the object's position in the image by developing the compensation table. The compensation is accomplished by facilitating users to obtain the correcting object and serves the objective of improving the precision of measurement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.305-311
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• 1993

In recent years, it has been variously developed for testing the accuracy of circular motion of NC machine tools, for example Telescoping Ball Bar Method by Bryan,Circular Test Method by Knapp and r $_{- \theta}$ Mathod by Tsutsumi etc., but it is not yet settled in the code of measuring methods of motion errors of NC machine tools, because of errors of measuring units and sensors, and also especially the difficulties of centering of measuring units. In this paper, in use of magnetic type linear scale with resolution of 0.5 .mu. m and tick pulses come out from computer, it has become possible for detecting of linear displacement of radial errors and measuring of revolution angle of circular motion of NC machine tools.