• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.1051-1058
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• 2020

The chemical mechanical planarization (CMP) is a process of physically and chemically polishing the semiconductor substrate. The planarization quality of a substrate can be evaluated by the within wafer non-uniformity (WIWNU). In order to improve WIWNU, it is important to manage the pad profile. In this study, a device capable of non-contact measurement of the pad thickness profile was developed. From the measured pad profile, the profile of the pad surface and the groove was extracted using the envelope function, and the pad thickness profile was derived using the difference between each profile. Thickness profiles of various CMP pads were measured using the developed PMS and envelope function. In the case of IC series pads, regardless of the pad wear amount, the envelopes closely follow the pad surface and grooves, making it easy to calculate the pad thickness profile. In the case of the H80 series pad, the pad thickness profile was easy to derive because the pad with a small wear amount did not reveal deep pores on the pad surface. However, the pad with a large wear amount make errors in the lower envelope profile, because there are pores deeper than the grooves. By removing these deep pores through filtering, the pad flatness could be clearly confirmed. Through the developed PMS and the pad thickness profile calculation method using the envelope function, the pad life, the amount of wear and the pad flatness can be easily derived and used for various pad analysis.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.4
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• pp.58-64
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• 1984

A simple model for the impurity profile in an ion-implanted channel layer of an enhancement type IGFET is assumed and a simple expression for the threshold voltage derived by using the assumed impurity profile is analyzed in detail. Also, this simple model is applied to simulating the substrate bias dependence of its threshold voltage. Excellent agreement is obtained between theory and experiment on n-channel devices. The error range of threshold voltage between gaussian-profile and box-profile is calculated in this paper and a new method of calculating the depth of ion-implanted Baler D is also introduced.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1685-1690
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• 2010

This paper describes the calculation and application of the speed profile for the train speed control when the train is operated by ATO(Automatic Train Operation). We propose a speed profile calculation method considering the speed limitation and the jerk limitation, in order to maintain the quality of the train automatic operation. In previous works, ATO calculates a desired speed profile along the time, and controls the train to follow the profile. In this case, it may be hard to follow the restrictive speed along the location or to stop the train with a low location error, because of the difference between the desired location at each time and the real location of the train due to the control error. In the proposed method in this paper, we calculate a desired speed profile along the time considering the speed and jerk limitation first, and derive a speed profile along the location using it. If the restrictive speed profile is changed or the train speed strayed from the speed profile, ATO system calculates new speed profile and applies it immediately. Because ATO system controls the train speed based on the train location, the accuracy of the train location control can be improved. A simulation system for the test of the automatic train operation using this method is designed.

• Research in Mathematical Education
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• v.26 no.3
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• pp.235-252
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• 2023

We investigated the classification of learner groups for students' mathematical modeling competency and analyzed the characteristics in each profile group for each country and variable using PISA 2012 data from six countries. With a perspective on measuring sub-competency, we applied the latent profile analysis method to student achievement for mathematical modeling variables - Formulate, Employ, Interpret. The findings showed the presence of 4-6 profile groups, with the variables exhibiting high and low achievement within each profile group varying by country, and a hierarchical structure was observed in the profile group distribution in all countries, interestingly, the Formulate variable showed the largest difference between high-achieving and low-achieving profile groups. These results have significant implications. Comparison by country, variable, and profile group can provide valuable insights into understanding the various characteristics of students' mathematical modeling competency. The Formulate variable could serve as the most suitable predictor of a student's profile group and the score range of other variables. We suggest further studies to gain more detailed insights into mathematical modeling competency with different cultural contexts.

• Tribology and Lubricants
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• v.18 no.6
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• pp.418-424
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• 2002

The basic concept of ‘gear profile modification’ is to change a part of the involute profile to reduce the load in that area and appropriate profile modifications can help gears to run quietly and resist scoring., pitting, and tooth breakage. In this study, the modification of tooth profile to make a smooth transmission of the normal loads in spur gears has been developed. The modified tooth profile has been determined by the total deflection at contact points. We also compared our results with other experimental results.

• Tribology and Lubricants
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• v.5 no.2
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• pp.107-112
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• 1989

This paper deals with strength analysis of tooth and method of manufacture of external tooth profile in harmonic drive. From the calculation of load imposed on the contact teeth, moximum contact stress is investigated to design the addendum modification coefficient. New tooth profile of the external gear is generated according to the law of gearing, assuming that internal gear has involute tooth profile. External tooth profile can't be manufactured by conventional exclusive tools which have pressure angle of 20$\circ$. The method to design cutter tooth profile is presented.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.664-669
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• 2004

In rolling stock, wheels are one of the most important components to run on the track in safety. Especially, it is important that wheel profile cause the variation of dynamic characteristics and running safety. The purpose of this paper is to propose the wheel profile and to know the effectiveness of improved wheel profile by using microphones. We also performed analysis of running safety to know application of improved wheel profile before the test. In result, the improved wheel profile was stable in running safety and noise level was reduced.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.79-84
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• 1996

Recently a symmetric and non-symmetric profile of screw rotor has been designed in the interior. Howere the processing method of screw rotor and the cutter design for screw rotor were not studied. Therefor we could not make the shape of the screw rotor designed by profile function with computer. In this study we have made cutter profile design program and manufactured cutters for screw rotors using H.S.S We machined screw rotors of symmetric 4x6 profile non-sysmmetric 4x6 profile with almighty milling machine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.907-912
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• 1994

Recently, a symmetric and non-symmetric profile of screw rotor has been designed in the interior. However the processing method of screw rotor and the cutter design for screw rotor were not studied. Therefore we could we could not make the shape of the screw rotor designed by profile function with computer. In this study, we have made cutter profile design program, and manufactured cutters for screw rotors using H.S.S. We have machined screw rotorts of symmetric 4*6 profile, non-symmetric 4*6 profile with almighty milling machine.

• Journal of the Korean Data and Information Science Society
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• v.17 no.3
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• pp.999-1007
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• 2006

The semiparametric gamma frailty models have been often used for multivariate survival analysis because they give an explicit marginal likelihood. The commonly used estimation procedure is the profile likelihood method based on marginal likelihood, which provides the same parameter estimates as the EM algorithm. In this paper we show in finite samples the standard profile-likelihood method can lead to an underestimation of parameters, particularly for the frailty parameter. To overcome this problem, we propose an adjusted profile-likelihood method. For the illustration a numerical example and a small-sample simulation study are presented.