• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.249-256
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• 2009

The widely used control theory based design of PI family controllers fails to perform satisfactorily under parameter variation, nonlinear or load disturbance. In high performance applications, it is useful to automatically extract the complex relation that represent the drive behaviour. The use of learning through example algorithms can be a powerful tool for automatic modelling variable speed drives. They can automatically extract a functional relationship representative of the drive behavior. These methods present some advantages over the classical ones since they do not rely on the precise knowledge of mathematical models and parameters. The paper proposes high performance speed and current control of synchronous reluctance motor(SynRM) drive using adaptive learning mechanism-fuzzy neural network (ALM-FNN) and fuzzy logic control (FLC) controller. The proposed controller is developed to ensure accurate speed and current control of SynRM drive under system disturbances and estimation of speed using artificial neural network(ANN) controller. Also, this paper proposes the analysis results to verify the effectiveness of the ALM-FNN, FLC and ANN controller.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.45-48
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• 2007

Thermochemical 2-step methane reforming, involving the reduction of metal oxide with methane to produce syn-gas and the oxidation of the reduced metal oxide with water to produce pure hydrogen, was investigated on ferrite-based metal oxide mediums and $WO_{3}/ZrO_{2}$. Thermochemical 2-step methane reforming were accomplished at 900 $^{\circ}C$(syn-gas production step) and 800 $^{\circ}C$(water-splitting step). In syn-gas production step, it appeared carbon deposition on metal oxides with increasing react ion time. Various mediums showed the different starting point of carbon deposition each other. To minimize the carbon deposition, the reaction time was controlled before the starting point of carbon deposition. As a result, $CO_{x}$ were not evolved in water-splitting step, Among the various metal oxides, $Mn-ferrite/ZrO_{2}$ showed high reactivity, proper $H_{2}/CO$ ratio, high selectivity of undesired $CO_{2}$ and high evolution of $H_{2}$.

• Journal of information and communication convergence engineering
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• v.7 no.1
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• pp.7-12
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• 2009

The advanced computer network and Internet technology enables connectivity of computers through an open network environment. Despite the growing numbers of security threats to networks, most intrusion detection identifies security attacks mainly by detecting misuse using a set of rules based on past hacking patterns. This pattern matching has a high rate of false positives and can not detect new hacking patterns, making it vulnerable to previously unidentified attack patterns and variations in attack and increasing false negatives. Intrusion detection and prevention technologies are thus required. We proposed a network based hybrid Probe Intrusion Detection model using Fuzzy cognitive maps (PIDuF) that detects intrusion by DoS (DDoS and PDoS) attack detection using packet analysis. A DoS attack typically appears as a probe and SYN flooding attack. SYN flooding using FCM model captures and analyzes packet information to detect SYN flooding attacks. Using the result of decision module analysis, which used FCM, the decision module measures the degree of danger of the DoS and trains the response module to deal with attacks. For the performance evaluation, the "IDS Evaluation Data Set" created by MIT was used. From the simulation we obtained the max-average true positive rate of 97.064% and the max-average false negative rate of 2.936%. The true positive error rate of the PIDuF is similar to that of Bernhard's true positive error rate.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.729-730
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• 2006

The paper is proposed maximum torque control of SynRM drive using adaptive fuzzy neural network(A-FNN) controller and artificial neural network(ANN). For each control mode, a condition that determines the optimal d-axis current $i_d$ for maximum torque operation is derived. The proposed control algorithm is applied to SynRM drive system controlled A-FNN and ANN controller, the operating characteristics controlled by maximum torque control are examined in detail. Also, this paper is proposed the analysis results to verify the effectiveness of the A-FNN and ANN controller.

• Journal of Magnetics
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• v.21 no.4
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• pp.544-553
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• 2016

Torque ripple minimization without decrease in average torque is a vital attribute in the design of Synchronous Reluctance (SynRel) motor. As the design of SynRel motor is an arduous task, which encompasses many design variables, this work first analyses the significance of the effect of varying the geometrical parameters on average torque and torque ripple and then proposes an extensive optimization procedure to obtain configurations with improved average torque and minimized torque ripple. A hardware prototype is fabricated and tested. The Finite Element Analysis (FEA) software tool used for validating the test results is MagNet 7.6.0.8. Multi Objective Particle Swarm Optimization (MOPSO) is used to determine the various designs meeting the requirements of reduced torque ripple and improved torque performance. The results indicate the efficacy of the proposed methodology and substantiate the utilization of MOPSO as a significant tool for solving design problems related to SynRel motor.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1001-1004
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• 2006

The m-calpain activity hydrolyzing a fluorogenic substrate of N-Succinyl-Leu-Leu-Val-Tyr-7-amino-4-methylcourmarin (LLVY-AMC) was significantly stimulated by more than two-fold in the presence of 5$\mu$M $\alpha$synuclein at $15{^{\circ}C}$. The stimulation was also confirmed with azocasein. The stimulation of the peptide hydrolyzing activity required structural intactness of $\alpha$-synuclein since the C-terminally or N-terminally modified proteins such as $\beta$-synuclein, $\alpha$-syn1-97, and $\alpha$-syn61-140 did not increase the proteolytic activity. Instead, however, the N-terminally truncated $\alpha$-syn61-140 was shown to drastically suppress the calpain activity. Since the N-terminal truncation was known to be the primary cleaving event of calpain-mediated proteolysis of $\alpha$-synuclein and the $\alpha$-syn61-140 has been demonstrated to be resistant against the calpain digestion, it has been proposed that the intracellular calpain activity could be regulated in a reciprocal manner by $\alpha$-synuclein and its proteolyzed C-terminal fragment. Based on the results, a possible physiological function of $\alpha$-synuclein has been suggested as a calpain regulator which contains both stimulatory and inhibitory activities.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.206-214
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• 1994

This experiment was conducted to find out the response of orchardgrass (Dactylis glomrrata L.) varieties to grazing at the condition of monocultures and mixed pastures on the field of Livestock Experiment Station at Suwon from Sep. 1989 to Oct. 1991. The varieties of orchardgrass used in this experiment were Potomac, Hallmark and Syn. No. 2 as a early maturing type, and Lidacta, Rancho and Syn. No. 10 as a late maturing type. The results obtained were as follows: I. Heading date of early maturing varieties among orchardgrass like as Potomac, Hallmark and Syn. 2 ranged from May 9 to May 14. Otherwise those of late varieties(Lidacta Rancho and Syn. 10) were between May 21 to May 25. Leaf types of early varieties were shown erect, those of late varieties were erect or semi-erect. 2. In dry matter production per ha, mixture with Rancho variety(T5) was the highest as 7.818 kg and mixture with Hallmark(T2) was the lowest as 7,013 kg. But there was not significantly different(P>0.05) among mixtures. While in monocultures, Syn. 10 variety was the highest(6.626 kglha) and Lidacta was Iowest(5,775 kg). But no difference was found(P>0.05). 3. In mean grass height after grazing, mixtures with early maturing types were higher as 9.8 cm than that of late (8.8cm), and early types were higher as 10.5cm than that of late(9.4cm) in monocultures. But there was no significant difference both mixtures and monocultures.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.588-594
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• 2017

Permanent magnet assisted synchronous reluctance motors (PMa-SynRM) show higher efficiency and power density compared to conventional induction motors for high speed railroad traction systems. Furthermore, 5-phase PMa-SynRMs have lower torque ripple and higher power density than 3-phase systems. Therefore, the 5-phase PMa-SynRM is suitable for high-speed railway traction systems. In this study, 3kw 3-phase and 5-phase PMa-SynRM models were optimized using lumped parameter model and genetic algorithm, and their characteristics were compared. The optimized models are fine-tuned using finite element analysis. The final models of the 3-phase and 5-phase PMa-SynRMs are fabricated and tested to verify the analysis results.

• Journal of Communications and Networks
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• v.10 no.4
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• pp.455-464
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• 2008

To provide network services consistently under various network failures, enterprise networks increasingly utilize path diversity through multi-homing. As a result, multi-homed non-transit autonomous systems become to surpass single-homed networks in number. In this paper, we address an inevitable problem that occurs when networks with multiple entry points deploy firewalls in their borders. The majority of today's firewalls use stateful inspection that exploits connection state for fine-grained control. However, stateful inspection has a topological restriction such that outgoing and incoming traffic of a connection should pass through a single firewall to execute desired packet filtering operation. Multi-homed networking environments suffer from this restriction and BGP policies provide only coarse control over communication paths. Due to these features and the characteristics of datagram routing, there exists a real possibility of asymmetric routing. This mismatch between the exit and entry firewalls for a connection causes connection establishment failures. In this paper, we formulate this phenomenon into a state-sharing problem among multiple fire walls under asymmetric routing condition. To solve this problem, we propose a stateful inspection protocol that requires very low processing and messaging overhead. Our protocol consists of the following two phases: 1) Generation of a TCP SYN cookie marked with the firewall identification number upon a SYN packet arrival, and 2) state sharing triggered by a SYN/ACK packet arrival in the absence of the trail of its initial SYN packet. We demonstrate that our protocol is scalable, robust, and simple enough to be deployed for high speed networks. It also transparently works under any client-server configurations. Last but not least, we present experimental results through a prototype implementation.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.29-31
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• 2009

Optimal efficiency control of synchronous reluctance motor(SynRM) is very important in the sense of energy saving and conservation of natural environment because the efficiency of the SynRM is generally lower than that of other types of AC motors. This paper is proposed an efficiency optimization control for the SynRM which minimizes the copper and iron losses. The design of the speed controller based on fuzzy-neural networks (FN)-PI controller that is implemented using fuzzy control and neural networks. There exists a variety of combinations of d and q-axis current which provide a specific motor torque. The objective of the efficiency optimization control is to seek a combination of d and q-axis current components, which provides minimum losses at a certain operating point in steady state. It is shown that the current components which directly govern the torque production have been very well regulated by the efficiency optimization control scheme. The proposed algorithm allows the electromagnetic losses In variable speed and torque drives to be reduced while keeping good torque control dynamics. The control performance of the proposed controller is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm.