• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.54-57
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• 2003

A new non linear, mean value, instantaneous following control technique to design half bridge converter is proposed in witch control principle uses characteristic that reset time of analog integrator is inverse proportion In input voltage. It is Important characteristic that compensation and follow-up control time are same with switching frequency. Is completed in one cycle that base control frequency. Have excellence characteristic that follow in order instruction value exactly stationary state as well as transient state. Half bridge converter that apply this control principle can know that have stabilize and excellence characteristic. This technique is verified through an experiment, and know that experiment result and theory agree well.

• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.203-214
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• 2005

In this study the optimal control of fed-batch glycerol fermentation is investigated based on an impulsive dynamical system. Considering the sudden increase of the glycerol and alkali in fed-batch culture of biodissimilation of glycerol to 1,3-propanediol, this paper proposes a non-linear impulsive system of fed-batch culture. The existence, uniqueness and regularity properties of piecewise solution for the system are proved. In view of the controllability of volumes of glycerol added to the reactor instantaneously, the paper constructs an optimal control model based on the nonlinear impulsive system and the existence of the optimal control is obtained. The control variables here are the moments and the sizes of jumps in the states at the discrete instants and the objective is to maximize the productivity of 1,3-propanediol over one cycle.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.387-397
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• 2007

According to the controllability of pulse times and the amount of jumps in the states at these times in the process of fed-batch culture producing 1,3-propanediol, this paper proposes a terminal optimal control model, whose constraint condition is the nonlinear impulsive delay system. The existence of optimal control is discussed and an optimization algorithm which is applied to each subinternal over one cycle for this optimal control problem is constructed. Finally, the numerical simulations show that the terminal intensity of producing 1,3-propanediol has been increased obviously.

• 정보과학회 논문지
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• 제45권2호
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• pp.175-186
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• 2018

최근 QoE를 향상시키기 위한 비디오 스트리밍 프로토콜로 HTTP 적응적 스트리밍이 주목받고있다. 높은 지연을 갖는 네트워크에서 HTTP 적응적 스트리밍은 하나의 세그먼트 요청에 하나의 세그먼트를 응답 받는 형식으로 동작하기 때문에 Lost RTT Cycle에 의해 평균 비디오 비트율이 감소한다. 하나의 요청에 다수의 세그먼트를 다운로드하는 Server-push 기반의 스트리밍 기법은 버퍼 언더플로우에 의한 QoE 저하가 발생한다. 본 논문에서는 높은 지연을 갖는 네트워크에서 HTTP 적응적 스트리밍의 QoE를 향상시키기 위한 VSSDS(Video Streaming Scheme based on Dynamic Server-push) 기법을 제안한다. 제안하는 기법은 가용대역폭을 예측하여 품질조절을 수행하고, 요청 주기마다 요청할 세그먼트의 개수를 결정한다. 실험을 통하여 제안하는 기법이 기존 기법에 비해 평균 비디오 비트율을 향상시키며, 버퍼 언더플로우를 방지하는 것을 확인하였다.

• 전기전자학회논문지
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• 제23권4호
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• pp.1208-1217
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• 2019

풀-브리지 서브모듈은 MMC의 단위 시스템으로서 서브모듈에 대한 수명예측은 HVDC 시스템의 유지 보수와 경제성 확보 관점에서 매우 중요하다. 그러나 일반적으로 부품의 종류, 개수, 결합 상태만을 고려하는 수명 예측은 대상 시스템의 구동상태를 고려하지 않는 일반화 된 결과로 실제 시스템의 수명과 크게 차이가 발생할 수 있다. 따라서 본 논문에서는 풀-브리지 서브모듈의 동작 특성을 반영하기 위한 목적으로 고장나무를 설계하고 기본 사상의 고장률에 MIL-HDBK-217F를 적용하여 풀-브리지 서브모듈의 수명을 예측한다. 기존의 부품고장률 분석과 제안된 고장나무 분석에 의한 기대 수명을 비교하고, 풀-브리지 서브모듈의 여유율 적용 여부에 따른 수명을 비교한다.

• The Plant Pathology Journal
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• 제38권5호
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• pp.472-481
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• 2022

Brown blotch disease, caused by Pseudomonas tolaasii, is one of the most serious diseases in mushroom cultivation, and its control remains an important issue. This study isolated and evaluated pathogen-specific bacteriophages for the biological control of the disease. In previous studies, 23 varieties of P. tolaasii were isolated from infected mushrooms with disease symptoms and classified into three subtypes, Ptα, Ptβ, and Ptγ, based on their 16S rRNA gene sequences analysis and pathogenic characters. In this study, 42 virulent bacteriophages were isolated against these pathogens and tested for their host range. Some phages could lyse more than two pathogens only within the corresponding subtype, and no phage exhibited a wide host range across different pathogen subtypes. To eliminate all pathogens of the Ptα, Ptβ, and Ptγ subtype, corresponding phages of one, six, and one strains were required, respectively. These phages were able to suppress the disease completely, as confirmed by the field-scale on-farm cultivation experiments. These results suggested that a cocktail of these eight phages is sufficient to control the disease induced by all 23 P. tolaasii pathogens. Additionally, the antibacterial effect of this phage cocktail persisted in the second cycle of mushroom growth on the cultivation bed.

• International Journal of Quality Innovation
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• 제5권2호
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• pp.63-69
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• 2004

This is an R&D project on design optimization of the inner shield of the Omega color picture tube at Samsung SDI in Korea. This was an R&D project which basically used the IDOV (Identify, Design, Optimize, Validate) process for Six Sigma implementation. Most Six Sgima projects use the process of DMAIC (Define, Measure, Analyze, Improve, Control). However, this project introduces a new cycle, RDIDOV (Recognize, Define, and IDOV). Here CPT means Color Picture Tube. Sam sung SDI is one of the two companies which began Six Sigma in Korea. This case study shows a good example how an R&D Six Sigma project can be usefully employed in manufacturing companies using a new process cycle.

• 지능정보연구
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• 제11권3호
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• pp.45-55
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• 2005

본 논문에서는 카오스 궤적 표면에서 불안정한 리미트 사이클을 가지는 카오스 무인 비행체의 동기화 기법을 제안하였다. 카오스 궤적 표면에서의 모든 장애물들은 불안정한 리미트 사이클을 가지는 반데어 폴(Van der Pol) 방정식을 가지고 있다고 가정하였다. 제안한 기법들은 만약 2대의 카오스 무인 비행체 중 한대가 동기화 명령을 받으면 나머지 한대의 무인 비행체는 임의의 표면상에 카오스적인 탐색을 하는 동안 동일한 궤적을 가지고 추종하게 됨을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.313-329
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• 2011

To provide a seamless network to customers, Internet service providers must promptly detect and control abnormal traffic. One approach is to shorten the traffic information measurement cycle. However, performance degradation is inevitable if traffic measurement servers merely shorten the cycle and measure all traffic. This paper presents a software architecture that can measure traffic more frequently without degrading performance by estimating the level of abnormal traffic. The algorithm in the architecture estimates the values of the interface group objects in MIB by using the IP group objects thereby reducing the number of measurements and the size of measured data. We evaluated this architecture on part of Internet service provider's IP network. When the traffic was measured 5 times more than before, the CPU usage and TPS of the proposed scheme was 7% and 41% less than that of the original scheme while the false positive rate and false negative rate were 3.2% and 2.7% respectively.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.291-295
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• 2004

New valve driving system to control for the best volumetric efficiency at each load of an internal combustion engine within one engine cycle has been developed. The system needs to reduce pumping loss that cause by throttle valve during the intake valve is opened. In this system the intake valve is driven by a linear DC electromagnetic actuator which is controlled by personal computer. The result is compared both installed and uninstalled actuator into the cylinder head. By both of experimental and numerical calculation, the responsibility of the valve driving system to the engine speed was examined