• 한국가시화정보학회지
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• 제14권2호
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• pp.46-51
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• 2016

In this study, a Masked Omni-Directional Integration(MODI) method for pressure calculation is proposed using the Particle Image Velocimetry (PIV) data. To obtain the velocity field, the Affine PIV method was adopted. Synthetic images were generated for a solid body rotation. Calculation on the pressure was based on the Navier-Stokes equation. The results obtained by the MODI were compared with those obtained by theoretical pressure and by the Omni-Directional Integration(ODI) method. It was shown that the minimum error by the proposed MODI method was attained when the mask size was 1.

• 공학교육연구
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• 제26권1호
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• pp.37-44
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• 2023

Recently, the Internet of Things is attracting attention as an important key technology of the 4th Industrial Revolution, and SW education using physical computing is suggested as a good alternative to supplement the problems raised by beginners in programming education. Among the many teaching tools that can be used for physical computing education, MODI is a modular manufacturing tool that anyone can easily assemble like Lego. MODI is a teaching tool that can improve learners' achievement by linking a self-linked block-type code editor called MODI Studio to lay the foundation for programming in a relatively small amount of time and immediately check the results in person. In this paper, a physical computing education method using MODI was designed to be applied to basic programming courses for programming beginners and applied to after-school classes for middle school students. As a result, it was found that students' interest and satisfaction were much higher in physical computing classes using MODI than in text-based programming classes. It can be seen that physical computing education that allows beginners to see and feel the results in person is more effective than grammar-oriented text programming, and it can have a positive effect on improving basic programming skills by increasing students' participation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.49-51
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• 1996

The z-transform method is a basic mathematical tool in analyzing and designing sampled-data control systems. However, since the z-transform method relates only the sampling-instants signals, another mathematical tool is necessary to describe the continous signals between the sampling instants. For this purpose the delayed and the modi fled z-transform methods were developed. The definition of the modi fled z-transform includes a sample in the interval [-T,0] of the original signal in its series expression, where the signal value is always zero for any physical system. From this reason one step skew of the time index always appears in its application formulas. This introduces an unnecessary operation and a gap in linking the mathematical formula and its physical interpretation. Considering the conceptual difficulty and application inconvenience, a method of using the advanced z-transform in analysis of sampled-data control systems is developed as a replacement of the modi fled z-transform. With one formulation of the advanced z-transform, now it is possible to relate both the signals of the sampling instants and those in between without any complication and conceptual difficulty.

• Journal of applied mathematics & informatics
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• 제42권5호
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• pp.1077-1090
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• 2024

In this study, a dual hesitant uncertain setting is employed to study the transportation issue. The dual hesitant fuzzy set handles ambiguous, unreliable, or inaccurate data as well as conditions in real-world practical research queries that are impossible or difficult to solve according to current fuzzy uncertainties. The dual hesitant fuzzy set (DHFS) is composed of a membership hesitant function as well as a non-membership hesitant function. In this investigation, we developed a new scoring formula for converting dual hesitant fuzzy numbers (DHFNs) to crisp values and suggested a novel algorithm called contraharmonic mean for addressing the dual hesitant fuzzy problem of transportation. Excel solver is utilized to find the contraharmonic mean. Additionally, we employed the modified distribution (MODI) method to achieve the best possible result. The recommended approach is then explained using a mathematical instance, and its efficacy can be demonstrated by comparing it to previously used techniques.

• East Asian mathematical journal
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• 제25권2호
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• pp.147-151
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• 2009

We use an improved Newton-Kantorovich theorem introduced in [2] to analyze interior point methods. Our approach requires less number of steps than before [5] to achieve a certain error tolerance for both Newton's and Modified Newton's methods.

• 한국인터넷방송통신학회논문지
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• 제21권5호
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• pp.181-188
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• 2021

총괄생산계획을 작성하는데 있어 운송법은 일반적으로 운송문제에 특화된 NCM, LCM, VAM 중 어느 하나로 초기 해를 구하고 SSM, MODI 중 어느 하나로 최적화를 수행하는 TSM에 대해 선형계획법 소프트웨어 패키지를 활용하고 있다. 반면에, 본 논문에서는 소프트웨어 패키지 도움 없이도 총괄생산계획을 쉽고 빠르며, 정확하게 작성하는 운송법을 제안한다. 제안된 알고리즘은 단순히 최소비용 우선 배정법을 적용하고, 재고기간을 최소화하는 방법을 제안하였다. 제안된 알고리즘을 6개의 실험데이터에 적용한 결과 VAM이나 LP에 비해 4개 데이터에 대해서는 보다 좋은 결과를, 나머지 2개 데이터에 대해서는 동일한 결과를 얻었다.

• 대한정형외과 초음파학회지
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• 제7권2호
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• pp.113-119
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• 2014

목적: 제 1천추 신경근 증상을 호소하는 추간판 탈출증 환자 및 척추 협착증 환자에서 초음파를 이용한 선택적 신경근 차단술을 실시하여 고식적인 방사선 영상 증폭기를 이용한 방법과 비교하여 그 결과 및 정확성에 대해 알아보고자 하였다. 대상 및 방법: 2012년 2월부터 2013년 12월까지 요추 추간판 탈출증이나 척추 협착증으로 발생한 하지 방사통을 주소로 내원한 환자 중 제1 천추 신경근 차단술을 시술 받은 38명을 대상으로 후향적으로 평가하였다. 초음파를 이용하여 시행한 18명(A군)과 방사선 영상 증폭기를 이용한 20명(B군)을 1개월 추시 관찰하였다. 효과 판정은 통증의 변화를 평가하기 위한 도구로 시각통증척도(VAS, Visual Analogue Scale)와 기능을 평가하기 위한 도구로 요통 기능장애척도(K-MODI, Korean Modified Oswestry Disability Index)를 이용하였으며, 각 시술 소요 시간을 확인하였다. 결과: VAS 점수는 A군에서 시술 전 $7.40{\pm}0.85$, 시술 1개월 후 $4.7{\pm}1.43$로 나타났고, B군에서 시술 전 $7.39{\pm}1.02$, 시술 1개월 후 $4.36{\pm}1.64$로 두 군 모두 유의한 감소를 보였다. 소요 시간은 A군이 $477.53{\pm}115.02$초, B군이 $492.47{\pm}144.38$초로 유의한 차이를 보이지 않았다. K-MODI는 A군에서 시술 전 $72.8{\pm}12.3$에서 시술 1개월 후 $43.3{\pm}10.3$로 나타났고, B군에서 시술 전 $73.8{\pm}11.5$에서 시술 1개월 후 $44.1{\pm}11.2$로 두 군 모두 유의한 감소를 보였다. 그러나 두 군 사이에서 VAS 점수 및 K-MODI 비교는 유의한 차이는 없었다. 결론: 초음파를 이용한 제 1천추 신경근 차단술은 방사선 영상 증폭기를 이용한 고식적인 방법에 비해 임상 결과 및 소요 시간에 차이는 없으나, 외래에서 간단히 시술 할 수 있는 장점이 있어 추간판 탈출증이나 척추 협착증 환자에서 유용한 시술 방법으로 사료된다.

• 응용통계연구
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• 제24권5호
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• pp.963-977
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• 2011

다변량 자료를 분석함에 있어 자료의 차원을 축소하는데 활용되는 중요한 툴 중 하나인 PCA 분석(주성분 분석, Principal Component Analysis)을 실시간으로 처리해야 하는 적용 분야가 최근 늘고 있다. PCA 분석에서는 표본 공분산 행렬의 고유값과 고유벡터를 도출하는 것이 관건인데, 자료의 양이 방대하며 고차원인 경우 이를 실시간으로 수행하기에는 어려움이 따른다. 이러한 문제점을 해결하기 위해서 Erdogmus 등 (2004)는 일차 섭동 이론(first order perturbation theory)을 활용하여 공분산 행렬의 고유값과 고유벡터를 추정하는 Recursive PCA 방법을 제안했다. 이 방법은 추가된 자료의 양이 많지 않은 경우는 상당히 정확하지만, 추가된 자료의 양이 많아짐에 따라 오차도 커진다는 한계를 가지고 있다. 본 논문은 공분산 행렬의 고유값과 고유벡터가 가지고 있는 수학적 관계를 이용하여 Erdogmus 등 (2004)가 제안한 Recursive PCA 방법을 수정한 Modi ed Recursive PCA 방법을 제안하다. 또한, 모의 실험을 통해 Recursive PCA 방법과 Modi ed Recursive PCA 방법에서의 고유값과 고유벡터 추정값의 정확도를 비교해 보았으며 그 결과 기존 Recursive PCA 방법 보다 정확한 추정이 가능함을 확인할 수 있었다.

• 대한수학회보
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• 제49권1호
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• pp.175-195
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• 2012

Representing planar Pythagorean hodograph (PH) curves by the complex roots of their hodographs, we standardize Farouki's double cubic method to become the undetermined junction point (UJP) method, and then prove the generic existence of solutions for general $C^1$ Hermite interpolation problems. We also extend the UJP method to solve $C^2$ Hermite interpolation problems with multiple PH cubics, and also prove the generic existence of solutions which consist of triple PH cubics with $C^1$ junction points. Further generalizing the UJP method, we go on to solve $C^2$ Hermite interpolation problems using two PH quintics with a $C^1$ junction point, and we also show the possibility of applying the modi e UJP method to $G^2[C^1]$ Hermite interpolation.

• 한국조경학회지
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• 제23권1호
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• pp.23-38
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• 1995

ELEECTRE is a less demanding and potentially Bffective multiattribute evaluation method for pre-editing proeedure. The method, however, was developed based on probabilistic mathematicsand its reliability has never'been emprieally tested. This article examined the reliability of ELECTRo under various conditions of linear and non-linear utility func- tions using a Monte-Carlo shnulation, and found the method eausea a considerably high rate of error. To enhance the reliability of ELECTRE, two ways of modi(ication - adjust- ment of threshold values of concordance and discordance matrices, and adjustment of the required nunlber of probably-dominant alternatives to eliminate a probably-dominated alternative - were suggested, and their effctiveness was also tesed by a Monte-Carlo simulation. The simulation result chows that these modifications cponsiderably improve the reliability of ELECTRE, and yet maintain a reasonably high level of efficiency. Through these modifications, ELECTRE can be used as an efficient and feliable pre-editing method. Ways to implement ELECTRE in the construction of plainning decision support systens were discussed. The impli(els combination of this method and other multiattribute evaluation methods will help to create more effective decision suport systems.