• Journal of applied mathematics & informatics
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• v.38 no.3_4
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• pp.255-260
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• 2020

Today most students have a smartphone. Students learning numerical analysis can practice coding using their smartphone in the classroom without going to the computer lab. The tool NAPHP[1] makes it easy to practice coding using PHP in an internet web browser without installing a coding app on your smartphone. This paper introduces a debugging tool for the NAPHP.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.95-102
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• 2003

Corestone rock mass has complex characters because it is made up of stronger and stiffer corestone in a weaker and softer matrix. Physical model corestone rock mass made up of stiffer corestone in weaker matrix were tested in uniaxial compression and numercal modelling analysis The result of the uniaxial compression tests showed that increasing the corestone proportion generally increased the modulus of deformation. And the strength decreased in the lower corestone proportion, but it increased in the higher proportion(45%, 65% corestone by volume). The strength and the modulus of deformation were not affected by different size coretone on the same proportion. The result of the numerical modelling analysis showed similar trend compared with the result of the result of the uniaxial compression test. But though the result of th uniaxial compression test is similar to the result of the numerical modelling analysis, it's unreasonalble to apply the results of this paper to in situ corestone rock mass. So mere laboratory tests including triaxial test and the other numerical program analyses are necessary to apply the results to in situ corestone mass

• Journal of applied mathematics & informatics
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• v.37 no.1_2
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• pp.157-162
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• 2019

Programming tools are essential for students learning numerical analysis. It is troublesome to go to a laboratory where a computer is located after taking a lecture. Nowadays most students have mobile phones which can be used for programming practice through the Internet. PHP is a server-side scripting language designed for web development but also used as a general-purpose programming language. However, PHP has many inconveniences, such as adding a dollar symbol ($) to every varable. This paper introduces a slightly modified language, NAPHP, and a system which is designed for students to use their own mobile phone to write down the language NAPHP and run it on the web page. The system NAPHP-SYS is an educational tool that turns NAPHP into PHP, run PHP code and show the results on the web.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.31 no.8
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• pp.33-38
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• 1982

This paper deals with the simplification of the transfer function in a frequency domain, viz. the integral of the squared errors between the original and the simplified model is minimized and the latter is estimated by the Walsh function. It tries to minimize the errors between the frequency responses of the two functions. This method is compared with the existing method by means of a numercal example. The frequency response of this simplified model approximates closely to that of the original model. The proposed method is simpler in analysis and easier in implementation than the existing methods. Though the Walsh function can be easily generated with the discrete values, it has errors because its zero crossings are not continuous. This method aims at the reduction of the errors in the real parts and the imaginary parts of the two functions by dividing into the more sub-intervals, and selecting the reduced-order model according to the response of the model. As a result, it can be applied for the simplification of higher order functions into lower order functions and for the design of control systems.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.2
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• pp.216-225
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• 1999

Four turbulent $k-{varepsilon}$models(i.e standard model modified models with streamline curvature modification and/or preferential dissipation modification) are applied in order to analyze the tur-bulent flow of wall-attaching offset jet. The upwind numerical scheme was adopted in the present analyses. The streamline curvature modification results in slightly better prediction while the preferential dissipation modification does not. The obtained analytic results will be used as refer-ences for further study regarding Reynolds stress model. In addition this paper introduced a method of increasing nozzle outlet velocity gradually for numercal convergence. Even though the method was simple it was efficient in view of convergent speed CPU running time computer memory storage programming etc.