• Communications for Statistical Applications and Methods
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• 제22권5호
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• pp.445-462
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• 2015

This article deals with the problem of estimation of the population mean in presence of multi-auxiliary information in two occasion rotation sampling. A multivariate exponential ratio type estimator has been proposed to estimate population mean at current (second) occasion using information on p-additional auxiliary variates which are positively correlated to study variates. The theoretical properties of the proposed estimator are investigated along with the discussion of optimum replacement strategies. The worthiness of proposed estimator has been justified by comparing it to well-known recent estimators that exist in the literature of rotation sampling. Theoretical results are justified through empirical investigations and a detailed study has been done by taking different choices of the correlation coefficients. A simulation study has been conducted to show the practicability of the proposed estimator.

• 에너지공학
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• 제8권4호
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• pp.512-518
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• 1999

본 논문은 각종 보조운전설비가 연계된 제지공장용 열병합발전시스템의 합리적인 운전계획을 수립하는 기법을 제시하였다. 보조운전설비로서는 보조보일러, 폐열보일러 및 슬러지 소각로가 있으며, 이 설비들이 다기 열병합발전시스템과 연계하여 운전되고 있다. 최적운전계획은 특히 환경을 고려하기 위해 목적함수에 환경요소를 추가하여 수립하였다. 전력은 구매할수있도록 전력회사와 연계되어 운전된다. 본 논문에서 제시한 최적운전계획기법은 제지공장의 에너지이용률을 향상시키는데 기여할 것으로 사료된다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제25권3호
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• pp.107-116
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• 2021

We introduce optimization algorithms using Bregman Divergence for solving non-negative matrix factorization (NMF) problems. Bregman divergence is known a generalization of some divergences such as Frobenius norm and KL divergence and etc. Some algorithms can be applicable to not only NMF with Frobenius norm but also NMF with more general Bregman divergence. Matrix Factorization is a popular non-convex optimization problem, for which alternating minimization schemes are mostly used. We develop the Bregman proximal gradient method applicable for all NMF formulated in any Bregman divergences. In the derivation of NMF algorithm for Bregman divergence, we need to use majorization/minimization(MM) for a proper auxiliary function. We present algorithmic aspects of NMF for Bregman divergence by using MM of auxiliary function.

• 조명전기설비학회논문지
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• 제22권3호
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• pp.40-51
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• 2008

This research presents a new active auxiliary resonant snubber with for induction heating PWM high frequency inverter solving the problem of induction heating PWM high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the active auxiliary resonant snubber with for induction heating PWM high frequency inverter. The inverter circuit which is attempted by the on-off operation of a switch has the effect of reducing the power loss due to soft switching and high frequency switching. This confirms that power regulation is possible on a continuous basis from 0.25[kW] to 2.84[kW] where the duty factor(D) changes from 0.08 to 0.3 under zero current switching which operates by an asymmetrical pulse width modulating control. The power conversion efficiency is 95[%]. Due to these results, the active auxiliary resonant snubber for an induction heating PWM high frequency inverter is considered effective as a source of induction heating.

• 전력전자학회논문지
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• 제22권2호
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• pp.140-149
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• 2017

This study proposes a new type of active-clamp forward-flyback converter with two transformers that operate in forward and flyback modes during on and off times, respectively, instead of not using an output inductor. The main switch can be turned on with zero-voltage switching (ZVS) using the leakage inductance of the transformer and the output capacitor of the main switch. The leakage inductance should be increased to ZVS. However, the ringing between the leakage inductance of the transformer and the parasitic output capacitance of the secondary side rectifier switches results in a serious voltage spike. A forward-flyback converter employing auxiliary inductor and auxiliary diode is proposed to overcome the problem. The operational principles are analyzed in detail and validated through experiments with a 385 V-to-53 V/37 A prototype.

• 산업경영시스템학회지
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• 제14권24호
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• pp.193-198
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• 1991

Is this paper the selection of a set of process plans is considered for a flexible manufacturing systems. This problem arises in the metal working industry when numerical controlled(N/C) machines are used to manufacture parts. In this paper a new concept to reduce the size of problem is proposed. A corresponding Integer programming model is formulated. The model formulated is to minimize corresponding manufacturing cost and minimize the number of tools and auxiliary devices such as fixtures, grippers, and feeders.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1404-1409
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• 2003

The sway control problem of the pendulum motion of the container crane hanging on the trolley, which transports containers from the container ship to the truck, is considered in this paper. In the container crane control problem, the main issue is to suppress the residual swing motion of the container at the end of the acceleration, deceleration or the case of that the unexpected disturbance input exists. For this problem, in general, the trolley motion control strategy is introduced and applied to real plants. In this paper, we suggest a new type of swing motion control system for a crane system in which a small auxiliary mass is installed on the spreader. The actuator reacting against the auxiliary mass applies inertial control forces to the spreader of the container crane to reduce the swing motion in the desired manner. In this paper, we consider that the length of the rope varies is we design the anti-sway control system based on LMI(linear matrix inequality) approach. And, it will be shown that the proposed control strategy is useful and it can be easily applicable to the real world. So, in this study, we investigate usefulness of the proposed anti-sway system and evaluate system performance from simulation and experimental studies.

• 대한토목학회논문집
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• 제30권2A호
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• pp.131-136
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• 2010

본 논문에서는 경계요소법의 모서리 문제(corner problem)의 해결책으로 제시된 다양한 알고리즘을 비교하였다. 비교를 위해 각각 기법을 반영한 프로그램을 작성하고, 이론적 바탕을 토대로 하여 기존의 방법 중 상호간에 새롭게 조합될 수 있는 추가조건식(auxiliary equation)을 찾아 새로운 알고리즘을 구성하였다. 새롭게 구성된 알고리즘과 기존 알고리즘에 대하여 3가지 종류의 수치 실험을 수행하였다. 수치해석모형은 정해가 알려진 2개의 문제와 기존 연구에서 제시된 한 개의 예제에 대하여 수행하였다. 이상을 바탕으로 기존 알고리즘의 특성을 기술하고 새롭게 제시된 알고리즘이 다양한 형태의 표면력을 반영할 수 있음을 보였다.

• 비파괴검사학회지
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• 제15권1호
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• pp.299-309
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• 1995

IR CAT Scan 개발을 위한 기하학적 역 열전도 문제의 해를 경계요소법 및 정규화 과정을 사용하여 구하였다. 이 문제에서는 잉여기술된 온도조건이 적외선 스캐닝에 의해 표면에 주어지며, 이 조건은 다른 조건과 함께 미지경계의 위치를 계산하는데 사용되었다. 문제의 해를 구하기 위해 보조문제가 도입되었고, 이 보조문제의 영역에 대한 가상적인 내부경계를 정의함으로써 공동(cavity)이 영역 내부에 위치하게 되며, 포텐셜 문제의 해를 구하여 그 위치를 결정하였다 이 문제의 해를 구하기 위해 경계요소법이 정규화과정과 함께 사용되었으며, 수치해석을 통하여 역 해법에 대한 정규화 효과를 분석하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권7호
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• pp.916-922
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• 2014

본 논문에서는 12-펄스정류기의 고조파 저감을 위해 12-펄스정류기의 커패시터 중앙 DC버스에 보조전원장치의 설치를 제안하였다. 그리고 이 장치에 의해 고조파가 감소되는 이론적인 배경을 다루었으며 부하전류의 크기에 따라 보조전원장치가 어떻게 제어되어야 하는지를 밝혔다. 본 논문에서 제안한 보조전원장치는 구형파 전압원을 적용함으로써 능동필터와 같은 다른 방식에 비해 시스템 구조가 간단하고 보다 저렴하다. 본 논문에서 제안하는 12-펄스정류기 고조파 저감법의 검증을 위해 소프트웨어 PSIM을 활용하였으며 제안된 방식의 유효성을 확인하였다.