• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.513-518
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• 2000

Surface roughness is one of the most important parameters to estimate quality of products. As this reason. so many studies were carried out through various attempts that were contact or non-contact using computer vision. Even though these efforts, there were few good results in this research. However, texture analysis is making a important role to solve these problems in various fields including universe, aviatiion, living thing and fibers. In this study, texture parameter was obtained by means of position operator according to variation of angle direction and distance. As a result, it was found that surface texture was more effected by direction then distance

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.332-338
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• 1999

Surface hardening of plain carbon steel (SM$%C) by Laser are usually much finer and stronger than those of the base metals. The present study was undertaken to investigate the wear resistance and a processing parameters such as, power density, pulse width, defocusing distance, and molten depth for surface modification of plain carbon steel. The wear test was carried out under experimental condition using the wear test device, and in which the annular surfaces of wear test specimens as well as mating specimen of alumina ceramics(Al2O3) was rubbed in dry sliding condition. It is shown that molten depth and width depend on defocusing distance. The wear loss on variation of sliding speed was much in lower speed range below 0.2m/sec and in higher speed range above 0.7m/sec, but wear loss was little in intermediate speed range. It depends on oxidation speed and wear speed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.585-590
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• 2000

Recently, It is gradually raised necessity that thickness of thin film is measured accuracy and managed in industrial circles and medical world. Ultrasonic Signal processing method is likely to become a very powerful method for NDE method of detection of microdefects and thickness measurement of thin film below the limit of Ultrasonic distance resolution in the opaque materials, provides useful information that cannot be obtained by a conventional measuring system. In the present research, considering a thin film below the limit of ultrasonic distance resolution sandwiched between three substances as acoustical analysis model, demonstrated the usefulness of ultrasonic Signal processing technique using information of ultrasonic frequency for NDE of measurements of thin film thickness, sound velocity, and step height, regardless of interference phenomenon. Numeral information was deduced and quantified effective information from the image. Also, pattern recognition of a defected input image was performed by neural network algorithm. Input pattern of various numeral was composed combinationally, and then, it was studied by neural network. Furthermore, possibility of pattern recognition was confirmed on artifical defected input data formed by simulation. Finally, application on unknown input pattern was also examined.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.832-839
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• 2005

It is important to understandflow characteristics and performances of sailsfor both sailors and designers who want to have efficient thrust of yacht. In this paper the viscous flows around sail-like rigid wings, which are similar to main and jib sails of a 30 feet sloop, are calculated using a CFD tool. Lift, drag and thrust forces are estimatedfor various conditions of gap distance between the two sails and the center of effort of the sail system is obtained. Wind tunnel experiments are also carried out to measure aerodynamic forces acting on the sail system and to validate the computation. It is found that the combination of two sails produces the lift force larger than the sum of that produced separately by each sail and the gap distance between the two sails is an important factor to determine total lift and thrust.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.4
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• pp.417-422
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• 2009

The injection mold cooling circuit optimization was studied with a response surface method in the previous research. It took so much time to find an optimum solution for a large product due to an extensive amount of calculation time for the CAE analysis. In order to use the optimization technique in the actual design process, the calculation time should be much reduced. In this study, we tried to reduce the number of design variables with the concept of the close relationship between the depth and the distance of cooling channel. The optimum ratio of the distance to the depth of cooling channels for a 2-dimensional problem was 2.0 so that the optimum ratio was again sought out for 4 large automotive parts. Therefore, the number of design variables for the cooling circuit optimization can be reduced in half, resulting in much faster running time for the optimization as a design tool.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.3
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• pp.906-918
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• 2012

Wireless Fidelity (WiFi) and Wireless microphone are assumed to operate on adjacent channels in TV White Spaces(TVWS). The Scenario of WiFi potentially interfering with Wireless microphone is analyzed through Minimum Coupling Loss (MCL) and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) based on the Monte-Carlo simulation method. In the case of single WiFi interfering with Wireless microphone, the protection distance between WiFi and the Wireless microphone should be at least 25.12 m to avoid WiFi impact on Wireless microphone. When the active number of WiFi is 12, the guard band between WiFi and Wireless microphone should not be less than 4.97 MHz to guarantee that WiFi does not interfere with the Wireless microphone.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.62-70
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• 2007

In this study, the natural flaws in welding parts are classified using the signal pattern classification method. The storage digital oscilloscope including FFT function and enveloped waveform generator is used and the signal pattern recognition procedure is made up the digital signal processing, feature extraction, feature selection and classifier design. It is composed with and discussed using the distance classifier that is based on euclidean distance the empirical Bayesian classifier. Feature extraction is performed using the class-mean scatter criteria. The signal pattern classification method is applied to the signal pattern recognition of natural flaws.

• East Asian Economic Review
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• v.21 no.1
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• pp.29-58
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• 2017

The third pillar of the Basel II highlights the role of market discipline in easing the existing pressure on traditional monitoring measures like capital requirement and government supervision. This study test the effectiveness of market discipline in inducing prudential risk management practices among the East Asian banks over the 1995 to 2005 period. Market discipline is measured using information disclosure and interbank deposit holdings. We find that only the latter is an effective market discipline tool. However, the former becomes effective when market concentration is higher. We find that government owned, foreign owned and recapilatised banks are subject to market disciplining when disclosure in taken account but the opposite is true when interbank deposits is taken into account. Finally, we find that banks that disclose more risk related information hold more capital against their non-performing loan. The implications of the findings are discussed.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1189-1198
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• 2017

Computer-aided design (CAD)-based Monte Carlo radiation transport is of value to the nuclear engineering community for its ability to conduct transport on high-fidelity models of nuclear systems, but it is more computationally expensive than native geometry representations. This work describes the adaptation of a rendering data structure, the signed distance field, as a geometric query tool for accelerating CAD-based transport in the direct-accelerated geometry Monte Carlo toolkit. Demonstrations of its effectiveness are shown for several problems. The beginnings of a predictive model for the data structure's utilization based on various problem parameters is also introduced.

• Journal of Engineering Education Research
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• v.25 no.5
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• pp.55-67
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• 2022

Distance learning has become an efficient tool and is being widely used at work and in school. This research presents the results of a project-oriented entrepreneurship course taught both in classroom and online for a period of 3 years before and after the pandemic caused by COVID-19. Despite the various challenges, the outcome demonstrated that the students were able to attain required knowledge and capabilities in the online learning environment. As such, this paper discusses effective ways to blend in distance learning components so that both instructors and students can benefit from Internet-based education technologies. In the future, both face-to-face and virtual project work and study are likely to get integrated into a 'hyflex' class, which is flexible, on-offline education.