• Proceedings of the KIPE Conference
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• 2003.07a
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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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• v.19 no.1_2
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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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• v.24 no.1_2
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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.

• Journal of KIISE
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• v.45 no.2
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• pp.175-186
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• 2018

Recently, HAS (HTTP Adaptive Streaming) has been the subject of much attention to improve the QoE (Quality of Experience). In a high latency network, HAS degrades the QoE due to the lost RTT cycle since it replies with a response of one segment to the request of one segment. The server-push based HAS schemes of downloading multiple segments in one request cause QoE degradation due to the buffer underflow. In this paper, we propose a VSSDS (Video Streaming Scheme based on Dynamic Server-push) scheme to improve the QoE in a high latency network. The proposed scheme adjust video quality by estimating available bandwidth and determine the number of segments to be downloaded for each segment request cycle. Through the simulation, the proposed scheme not only improves the average video bitrate but also alleviates the buffer underflow.

• Journal of IKEEE
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• v.23 no.4
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• pp.1208-1217
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• 2019

The life-cycle prediction of the sub-module which is the unit system of MMC is very important from the viewpoint of maintenance and economic feasibility of HVDC system. However, the life-cycle prediction that considers only the type, number and combination of parts is a generalized result that does not take into account the operating condition of the sub-module, and may significantly differ from the life-cycle of the actual one. Therefore, we design a fault tree for the purpose of reflecting the operation characteristics of the full-bridge sub-module and apply the MIL-HDBK-217F to the failure rate of the basic event to predict the life-cycle of the full-bridge sub-module. It compares the life-cycle expectancy of the conventional failure rate analysis with the proposed fault-tree analysis and compares the lifetime according to whether the redundancy of the full-bridge sub-module is considered.

• The Plant Pathology Journal
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• v.38 no.5
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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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• v.5 no.2
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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.

• Journal of Intelligence and Information Systems
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• v.11 no.3
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• pp.45-55
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• 2005

In this paper, we propose a method to a synchronization of chaotic UAVs(Unmanned Aerial Vehicle) that have unstable limit cycles in a chaos trajectory surface. We assume all obstacles in the chaos trajectory surface have a Van der Pol equation with an unstable limit cycle. The proposed methods are assumed that if one of two chaotic UAVs receives the synchronization command, the other UAV also follows the same trajectory during the chaotic UAVs search on the arbitrary surface.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.2
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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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• 2004.08a
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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