• Journal of the Korean Data and Information Science Society
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• 제24권1호
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• pp.33-39
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• 2013

반응변수의 변환을 고려하는 부분선형모형에서 이상치 문제는 선형모형에서와 마찬가지로 반응변수 변환모수의 추정에 왜곡된 결과를 초래할 수 있다. 이를 해결하기 위해서는 부분선형모형에서 반응변수 변환 모수 추정과 이상치 탐지 과정이 수행되어야 하지만 모형에 포함된 비모수 함수의 비정형성에 따른 어려움이 크다. 본 연구에서는 부분선형모형의 비모수함수에 대한 추정과 순차적 검정, 최대절사우도추정 등과 같은 이상치 제거방법의 적용을 통하여 부분선형모형에서 이상치에 강건한 반응변수 변환 과정을 제안한다. 제안된 방법들은 모의실험과 예제를 통해 효과를 비교 검증한다.

• Journal of the Korean Statistical Society
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• 제25권1호
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• pp.111-122
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• 1996

A model for a system whose state changes continuously with time is introduced. It is assumed that the system is modeled by a Brownian motion with negative drift and an absorbing barrier at the origin. A repairman arrives according to a Poisson process and repairs the system according to an (s,S) policy, i.e., he increases the state of the system up to S if and only if the state is below s. A partial differential equation is derived for the distribution function of X(t), the state of the system at time t, and the Laplace-Stieltjes transform of the distribution function is obtained by solving the partial differential equation. For the stationary case the explicit expression is deduced for the distribution function of the stationary state of the system.

• International Journal of Precision Engineering and Manufacturing
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• 제3권4호
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• pp.87-93
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• 2002

In this study, basic concepts of magnet were introduced, and dynamic characteristics of magnet coupling were explored. Based on these characteristics, it was proposed how to analyze transverse and torsional vibrations of a spindle system with magnet coupling. Proposed theoretical approaches were applied to a precision power transmission system machined for this study, and the transverse and torsional vibrations were simulated. The force on magnet coupling was shown as a form of nonlinear function of the gap and the eccentricity. Also, the form of torque transmitted by magnet coupling was considered as a sinusoidal function. Main spindle connected to a coupling of a follower part was assumed to be a rigid body. Nonlinear partial differential equation was derived to be as a function of angular displacement. By using the equation, torsional vibration analysis of a spindle system with magnet coupling was performed. Free and forced vibration analyses of a spindle system with magnetic coupling were explored by using FEM.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1990년도 추계학술대회논문집; 한양대학교, 서울; 24 Nov. 1990
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• pp.3-8
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• 1990

소음/진동 문제를 해결하는 데 있어서 우선은 소음/진동원들의 위치를 알아 내고 그들 중에 비중이 가장 큰 소음/진동원을 파악하는 것이 중요하다. 다 입력/단일출력 모형을 이용한 소음/진동원 규명에 대한 방법에는 주파수 응 답함수를 이용하는 방법(frequency response function approach)과 부분 기여 도 함수(partial coherence function)를 이용하는 방법 등이 있는데, 입력들 사이의 상호상관(correlation)이 없는 경우에는 전자의 방법을 사용하여 출력 에 가장 큰 비중을 차지하는 소음/진동원을 알아낼 수 있으나 상호상관이 존 재하는 경우에는 후자의 방법을 사용하게 된다. 그러나 후자의 방법을 적용 함에 있어서도 기본적으로 소음/진동원들의 위치를 알아야 하는 것 이외에 그들 사이의 원인.효과관계(causaling), 또는 우선순위(rank)를 우선적으로 아 는 것이 중요한데 이는 입력들 사이의 우선순위를 어떻게 두느냐에 따라 해 석 결과가 다르게 나타나기 때문이다 [1,2,3]. 본 연구에서는 부분 기여도 함 수를 이용하여 소음/진동원을 규명할 때 그들 사이의 우선순위를 결정하는 방법을 제시하고 2입력/1출력 모형에 대해 적용하여 보았다.

• 대한수학회보
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• 제58권5호
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• pp.1175-1192
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• 2021

In this paper, we have studied on the uniqueness problems of meromorphic functions with its linear c-shift operator in the light of partial sharing. Our two results improve and generalize two very recent results of Noulorvang-Pham [Bull. Korean Math. Soc. 57 (2020), no. 5, 1083-1094] in some sense. In addition, our other results have improved and generalized a series of results due to Lü-Lü [Comput. Methods Funct. Theo. 17 (2017), no. 3, 395-403], Zhen [J. Contemp. Math. Anal. 54 (2019), no. 5, 296-301] and Banerjee-Bhattacharyya [Adv. Differ. Equ. 509 (2019), 1-23]. We have exhibited a number of examples to show that some conditions used in our results are essential.

• 전기학회논문지
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• 제67권2호
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• pp.216-223
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• 2018

Since solar cells have non-linear voltage-current output characteristics, Photovoltaic systems require the Maximum Power Point Tracking(MPPT) function. For this reason, a large number of MPPT techniques have been studied. However, the conventional MPPT techniques may fail to track the maximum power point when partial shading occurs in the solar cell array due to its characteristics. Therefore, it is necessary to research the MPPT technique that can follow the maximum power point in the partial shadow condition. In this paper, the characteristics of solar cell arrays in partial shadowing are analyzed and the MPPT technique which can follow the maximum power point in partial shadow condition has been proposed. To validate the proposed MPPT method, simulation and experimentation results are provided.

• 한국세라믹학회지
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• 제27권7호
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• pp.841-850
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• 1990

The electrical conductivity of SrTiO3 thick films, which has been prepared by screen printing and sintering on polycrystalline Al2O3 substrates, was determined as a function of oxygen partial pressure and temperature. The data showed that electrical conductivity was proportional to the -1/4th power of the oxygen partial pressure for the oxygen partial pressure range from 10-4-10-8 to 10-20 atm and proportional to Po2+1/4 for the oxygen partial pressure range from 10-6-10-4 to 1atm. And then n-p transition region of electrical conductivity moved to lower oxygen partial pressure region as the sintering temperature of thick film specimens increased under about 140$0^{\circ}C$. These data were consistent with the presence of small amounts of acceptor impurities in SrTiO3 thick film which have been diffused from Al2O3 substrate in the range of solid solubility limit.

• 구강회복응용과학지
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• 제23권2호
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• pp.139-144
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• 2007

Prosthodontic treatment planning for various edentulous arches is not an easy issue for dentists. Especially, in case of removable partial denture, we must have a knowledge of overall treatment procedures, and a careful approach is needed. Recently, interest of dental implant and case reports are increasing, the decrease of the removable partial denture is true, but dental implantation takes longer treatment period and it is more expensive. Also, there are still some limitations like lack of available alveolar bone, patient's general condition, and chronic periodontitis. Therefore, sometimes implantation is impossible. Finally, implantation cannot be adapted to every single patient. Currently, the clasp type removable partial dentures are used routinely, giving patients many unesthetic and functional difficulties. With better laboratory technique, removable partial denture with attachment and removable partial denture in rigid type increase patient's happiness level much more than predicted. The case presented in this article, clinically demonstrate the efficiency of using a telescopic system to improve esthetic and functional recovery for patients who lose multiple teeth.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.526-531
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• 1992

Partial derivatives are easily computed analytically assuming that all the geometric information is known. However, there are computational difficulties in getting accurate partial derivatives directly from a range image since an image is a discrete version of continuous data contaminated with some noise. In this paper, we develop a general window function to compute partial derivatives based on the least square surface fitting method. A dynamic selective surface fitting method is introduced to make the window less sensitive to noise. Any degree of partial derivative can be obtained by a simple convolution between an image and window functions.

• Journal of Korean Dental Science
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• 제15권1호
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• pp.75-83
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• 2022

Crown-type implant-assisted removable partial dentures (CIRPDs) can be a feasible treatment option for partially edentulous patients. Here we report a case with remaining unilateral mandibular teeth. Two implants were placed in the posterior portion of the mandible using a surgical guide, and a distal-extension removable partial denture with implant-supported surveyed crowns was fabricated. After 12 months, both the abutment teeth and implants were in good condition. The treatment outcomes were satisfactory in terms of masticatory function and esthetics. The advantages of CIRPDs and considerations for obtaining successful clinical outcomes with these dentures are also discussed.