• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.283-293
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• 2007

This paper considers single machine scheduling problems with group technology (GT) and deteriorating jobs. A sequence independent setup is required to process a job from a different group and jobs in each group are processed together. We consider the case of jobs whose processing times are a decreasing function of their starting time. The objectives of scheduling problems are to minimize the makespan and the total completion time, respectively. We also provide polynomial time algorithms to solve these problems.

• 한국자동차공학회논문집
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• 제23권2호
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• pp.214-220
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• 2015

Since resources of fossil fuels are limited, development of alternative energies is emphasized and research on new-regenerative energy is actively in progress worldwide. In present research, physical and chemical characteristics of mixed fuel are analyzed in detail for the different mixture rate of conventional and bio-diesel and ultrasonic irradiation time. Experimental setup consists of ultrasonic generator, vibrator, horn, and reflector. Various physical and chemical characteristics of fuel are investigated for volumetric mixture rate of bio-diesel from 0 to 100%. As results, viscosity and surface tension is increased as mixture rate of bio-diesel is increased. Also, molecular splits and reunions are increased and decreased repeatedly after some period of time as ultrasonic energy irradiation time is increased. As conclusion of experiments, Olefin rate, Branch index, and Aromatic rate are influenced by ultrasonic irradiation time.

• Journal of the Optical Society of Korea
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• 제10권2호
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• pp.91-95
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• 2006

Blood pressure was predicted from photoplethysmography (PPG). To obtain PPG, backscattered light from a fingertip was measured and its waveform was analyzed. Systolic upstroke time and diastolic time in the pulse waveform were used as parameters to predict blood pressure. The experiment was carried out with five subjects on five different days. The systolic upstroke time had a correlation coefficient of -0.605 with respect to systolic blood pressure and the diastolic time had a correlation coefficients of -0.764 for diastolic pressure. This PPG method does not require an air-cuff installation on the arm and can predict blood pressure continuously. This simple LED/photo detector setup can be a good candidate for nonconstrained monitoring of blood pressure variations.

• Journal of Power Electronics
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• 제13권1호
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• pp.77-85
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• 2013

This paper proposes a new dead time compensation method of independent six-phase permanent magnet synchronous motors (IS-PMSM). The current of the independent phase machines contains odd-numbered harmonics because of the dead time and the nonlinear characteristics of the switching devices. By using the d-q-n three-dimensional vector analysis, these harmonics can be extracted at the n-axis current. Thus, the current distortion can be compensated by controlling the n-axis current of the IS-PMSM to zero. The proposed method is simple and can be easily implemented without additional hardware setup. The validity of the proposed compensation method is verified with simulations and several experiments.

• 한국멀티미디어학회논문지
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• 제21권11호
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• pp.1327-1332
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• 2018

An AGV(Automated Guided Vehicle) where is running on production automated system is related efficiency of production system similarly. On previous study proposed a path collision avoidance algorithms using shortest path of AGV. Running time about loading and unloading with shortest path of AGV is important factor to decide the production system efficiency. In this paper, we propose a method of shortest path and shortest time. Also propose the decision making method of collision avoidance position for setup a shortest runway for next command. To do verify the proposed method consist a simulation for AGV. Finally, we compare and analyse the proposed system between the existing system and show that our system can effectively the performance.

• 한국항만학회지
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• 제10권1호
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• pp.25-36
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• 1996

Generally, it is pointed out that a nonlinear analysis is needed to estimate accurately the water surface fluctuation and dynamic responses of a floating structure in case of large wave reflection. In this study, a frequency-domain method is applied and newly developed to analyze the nonlinear characteristics of the air-chamber floating breakwater. The air-chamber floating breakwater in this study can control well the wave transformation, motions of the structure and its natural frequency by adjusting the air depth in the chamber. Experiments are carried out to verify the numerical results. It is appeared that the mean water level is setup in the anti-node and setdown in the node, while the nonlinearity in wave profile is larger in the node than in the anti-node. Because of vertical mooring system, the sway, especially the time-independent nonlinear component, plays predominant role in the motion. On the other hand, the time-dependent component, as well as the time-independent one to the tensile force of mooring line contributes greatly, and the time averaged value presents tensional force oriented to the onshore side due drift force.

• ETRI Journal
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• 제26권3호
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• pp.203-217
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• 2004

This paper presents a method and architecture to analyze streaming media and multimedia conferencing traffic. Our method is based on detecting the transport protocol and port numbers that are dynamically assigned during the setup between communicating parties. We then apply such information to analyze traffic generated by the most popular streaming media and multimedia conferencing applications, namely, Windows Media, Real Networks, QuickTime, SIP and H.323. We also describe a prototype implementation of a traffic monitoring and analysis system that uses our method and architecture.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 가을 학술발표논문집 Vol.29 No.2 (3)
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• pp.94-96
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• 2002

기존의 연구에서는 광 경로를 설정할 때 파장 전체를 할당함으로써 많은 대역폭 낭비를 초래하였고, 타임슬롯을 할당할 때 처음 소스 노드에서 사용할 타임슬롯을 정하여 호연결 설정 (Call Setup) 을 함으로써 광 경로가 블록킹될 확률이 높았다. 본 논문에서는 광네트워크에서 효율적으로 RWTA 문제를 해결하기 위한 새로운 타임슬롯 할당 알고리즘을제안한다. 본 논문에서 제안하는 알고리즘은 호 연결 설정 시간까지의 타임슬롯 할당을 지연함으로써 광 경로가 블록킹될 확률을 최소화 할 수 있는 장점을 지닌 최근성 (recency) 에 근거한 타임슬롯 할당 알고리즘이다.

• 경영과학
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• 제30권3호
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• pp.81-97
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• 2013

This paper considers a parallel-machine scheduling problem with dedicated and common processing machines. Non-identical setup and processing times are assumed for each machine. A genetic algorithm is proposed to minimize the makespan objective measure. In this paper, a lowerbound and some heuristic algorithms are derived and tested through computational experiments.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1992년도 춘계공동학술대회 발표논문 및 초록집; 울산대학교, 울산; 01월 02일 May 1992
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• pp.332-341
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• 1992

본 연구에서는 가동준비 비용과 시간의 특수구조를 갖는 다품종 제품군이 있을때의 생산일정계획을 고려하며, 제품군 가동준비에 있어서의 작업순서간 상호의존성에 따라 일정계획 문제를 분류하고, 그 문제들을 정형화시킨다. 특히, 하나의 제품군만이 생산되어지는 작업환경에 대하여 발견적 기법을 개발하여 이를 적용한 생산계획을 마련한다. 또한, 그 결과를 정수선형 계획에 의한 최적해와 비교.분석한다.