• Smart Structures and Systems
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• v.4 no.4
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• pp.493-515
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• 2008

Semi-active control systems have attracted a great deal of attention in recent years because these systems can operate on battery power alone, proving advantageous during seismic events when the main power source of the structure may likely fail. The behavior of semi-active devices is often highly non-linear and requires suitable and efficient control algorithm. This paper presents the comparative study and performance of variable semi-active friction dampers by using recently proposed predictive control law with direct output feedback. In this control law, the variable slip force of semi-active variable friction damper is kept slightly lower than the critical friction force, which allows the damper to remain in the slip state during an earthquake, resulting in improved energy dissipation capability. This control algorithm is able to produce a continuous and smooth slip forces for a variable friction damper. The numerical examples include a structure controlled with multiple variable semi-active friction dampers and with multiple passive friction dampers. A parameter, gain multiplier defined as the ratio of damper force to critical damper control force, is investigated under four different real earthquake ground motions, which plays an important role in the present control algorithm of the damper. The numerically evaluated optimum parametric value is considered for the analysis of the structure with dampers. The numerical results of the variable friction dampers show better performance over the passive dampers in reducing the seismic response of structures.

• Journal of Power Electronics
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• v.11 no.3
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• pp.311-318
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• 2011

LCL filters installed at converter outputs offer a higher harmonic attenuation than L filters. However, as a three order resonant circuit, it is difficult to stabilize and has a risk of oscillating with the power grid. Therefore, careful design is required to damp LCL resonance. Compared to a passive damping method, an active damping method is a more attractive solution for this problem, since it avoids extra power losses. In this paper, the damping capabilities of capacitor current, capacitor voltage, and grid-side current feedback methods, are analyzed under the discrete-time state-space model. Theoretical analysis shows that the grid-side current feedback method is more suitable for use in active power filters, because it can damp LCL resonance more effectively than the other two methods when the ratio of the resonance and the control frequency is between 0.225 and 0.325. Furthermore, since there is no need for extra sensors for additional states measurements, this method provides a cost-efficient solution. To support the theoretical analysis, the proposed method is tested on a 7-kVA single-phase shunt active power filter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.538-546
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• 2007

A new 3-phase line-interactive UPS(Uninterruptible Power Supply) system with parallel-series active power-line conditioning capability using AC line reactor and two four-leg PWM VSCs(Voltage Source Converters) was introduced recently. In this paper, the strategy of voltage control in suggested UPS system is explained. The objective of proposed voltage controllers in parallel(shunt) and series PWM VSC is to guarantee satisfactory characteristics in steady state and transient state. Therefore the experimental results to prototype UPS system having power rating of 60kVA is shown to prove the verification of voltage control strategy.

• BMB Reports
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• v.31 no.5
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• pp.444-452
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• 1998

The visible spectra of soybean ferric leghemoglobin reductase exhibited a charge transfer band at 530 nm under aerobic condition. Spectra of the oxidized enzyme show a flavin peak at 454 nm and the enzyme has three redox states associated with the active site of the enzyme. The enzyme has an active disulfide bridge and two-electron transfer may dominate in the ferric state of leghemoglobin reduction. The midpoint potentials of the enzyme were determined by spectrotitration to be -0.294 V for disulfide/dithiol and -0.318 V for FAD/$FADH_2$. Since the midpoint potentials for $NAD^+$/NADH and the ferrous/ferric states of leghemoglobin are -0.32 V and +0.22 V, respectively, it is proposed that two electrons are transferred sequentially from NADH to FAD, to the disulfide group, and then to the ferric state of leghemoglobin in the enzyme reaction.

• Journal of the Korea Society for Simulation
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• v.14 no.4
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• pp.77-86
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• 2005

[ $IP^2$ ] (IP-based IMT Network Platform) is a ubiquitous platform supporting mobility using two step If address IPha (IP host address) and IPra (IP routing address) - in a backbone network. MN (Mobile Node) in $IP^2$ maintains either Active or Dormant state, which is transferred to Active state through Paging process when communication is required. In this paper, we proposed a Paging method using proxy to resolve the problem of the conventional Paging method which transmits the Paging messages to all cells in LA (Location Area) resulting in the excessive use of network resources. Performanceevaluation of the proposed method using NS-2 showed that the usage of network resources becomes more efficient by reducing paging loads, especially under the condition of increased nodes.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.572-580
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• 2013

Power metering and monitoring system is a basic element of Smart Grid technology. This paper proposes a new Non-Intrusive Load Monitoring (NILM) method for a residential buildings sector using the measured total active power consumption. Home electrical appliances are classified by ON/OFF state models, Multi-state models, and Composite models according to their operational characteristics observed by experiments. In order to disaggregate the operation and the power consumption of each model, an algorithm which includes a switching function, a truth table matrix, and a matching process is presented. Typical profiles of each appliances and disaggregation results are shown and classified. To improve the accuracy, a Time Lagging (TL) algorithm and a Permanent-On model (PO) algorithm are additionally proposed. The method is validated as comparing the simulation results to the experimental ones with high accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.490-495
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• 1998

In this paper an asymmetric hydraulic actuator which consists of single acting cylinder and servo valve is modeled for a quarter car active suspension system. This model regards the force as an internal state rather than a control input. The control input of the model is the sum of oil flows that pass through the valve's orifices. The resulting dynamic equation in the state space ap-pears a feedback connection of a nominal linear time in-variant term with a nonlinear bounded uncertain block. Since this model makes it possible to eliminate the force control phase, analysis and controller design are made straightforward and simple. Well known LQR method is then applied. Simulation and test rig experiment show the effectiveness of this approach in modeling and control.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1345-1362
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• 2019

Most active queue management algorithms manage network congestion based on the size of the queue but ignore the network environment which makes queue size change. It seriously affects the response speed of the algorithm. In this paper, a new AQM algorithm named CT-AQM (Change Trend-Adaptive Queue Management) is proposed. CT-AQM predicts the change trend of queue size in the soon future based on the change rate of queue size and the network environment, and optimizes its dropping function. Simulation results indicate that CT-AQM scheme has a significant improvement in loss-rate and throughput.

• Journal of Haehwa Medicine
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• v.22 no.2
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• pp.13-21
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• 2014

Subject : Kim hong-kyung(金洪卿)'s view of eight extra meridians Object : Kim hong-kyung has not only deeply studied Saam acupuncture but also the function and characteristics of extra meridian at the same time. Especially, he has tried the study to connect yin yang wei qiao mai(陰陽維蹻脈) with Lee je-ma(李濟馬)'s four trigram constitution theory, therefore the author felt the need to make public the theory and started reserch on the theory. Method : I researched the physiological properties of extra meridians through the past eastern medical literature, I reported on the types of people to show well the properties of extra meridians gathering Kum-oh's verbal explanation when I had classes from him. Result : Kum-oh Kim hong-kyung defined meridians as passways of consciousness and feeling, he interpreted 12 meridians and extra meridians with the view of mind, which has very important meanings in the history of acupuncture in the point of first trial to interpret meridians from this view. He explained Ren mai(任脈) and Du mai(督脈) are meridians which show clearly properties of yin-yang to appear trusts of affirmation and distrusts of denial in the mind, as Ren(任) means entrusting and Du(督) means supervising in English. He explained Chong mai(衝脈) is the meridian representing impulsive man that has a meaning of impulse as being suggested the name of Chong mai, because Chong mai is borrowed from Foot shao yin kidney meridian(足少陰腎經). Dai mai(帶脈) is the meridian representing the characteristics of woman that has a meaning of binding as being suggested from the name of Dai mai which acts when people have something on their flank or they are pregnant, because Dai mai borrowed from Foot shao yang gall bladder meridian. He thought that four trigram divided from yin and yang is innate trigram, so Yang wei mai(陽維脈), Yin wei mai(陰維脈), Yang qiao mai(陽蹻脈), Yin qiao mai(陰蹻脈) among extra meridians have connections with Tai-yang ren(太陽人), Tai-yin ren(太陰人), Shao-yin ren(少陰人), Shao-yang ren(少陽人) of Four trigram constitution theory respectively which was created by Lee je-ma. He explained yang means opponents and wei(維) means binding. Yang wei mai is the meridian to be active when opponents bind or intervene in you, also the meridian is well active to the people who easily criticize others who are rude, to the people who well refuse restraints from organization. Because he explained yin means me and wei(維) means binding. Yin wei mai is the meridian to be active when I bind and intervene in opponents. He also state that the meridian is easily active to the people who have a tendency to gather people and make party apparatus by nature. He explained Yang qiao mai is the meridian to be active in the situation that people are waiting for others to bridge gap because yang means opponents and qiao(蹻) which has a meaning of standing on one's tiptoes means bridging gap between people. He also state the meridian is easily active to Shao yin ren who has a tendency to be passive, to easily settle down and not to move by nature. He explained Yin qiao mai is the meridian to be active in the situation that I bridge gap between me and others to make friends, because yin means me and qiao(蹻) which has a meaning of standing on one's tiptoes means bridging gap between me and others. He also state the meridian is easily active to Shao yang ren who is active in every business and who has remarkable ability to make friends. Conclusion : Kim hong-kyung stated the physiological properties of extra meridians as below. Ren mai is the meridian representing positive confidence which is easily active when people have a mind to trust others, Du mai is the meridian representing negative distrust which is easily active when people have doubts. Chong mai is the meridian representing the characteristics of man that has impulsive characteristics. Dai mai is the meridian representing the characteristics of woman to be easily active when she is pregnant. Yang wei mai has close connections with Tai-yang ren who has a tendency to refuse restraints from others and to criticize on opponent's remarks and behaviors that are wrong. Yin wei mai has close connections with Tai-yin ren, as the meridian is active in the situation that people enjoy restraining and intervening in others. Yang qiao mai has close connections with Shao yin ren, as the meridian is active to the people who are negative and passive by nature. Yin qiao mai has close connections with Shao yang yin who has a strong tendency to make friends easily by nature.

• Journal of Power Electronics
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• v.5 no.1
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• pp.29-35
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• 2005

This paper presents a novel prototype of an active auxiliary quasi-resonant snubber(Auxiliary Quasi-Resonant Commutation Block-Link; ARCB)-assisted three phase voltage source soft switching space voltage vector modulated PFC rectifier, which uses Zero Voltage Soft Switching (ZVS) commutation. The operating principles of this digitally-controlled three phase soft switching PWM-PFC rectifier system with an instantaneous power feedback scheme are illustrated and its steady-state performance is evaluated using computer-aided simulation analysis.