• Journal of Ginseng Research
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• v.48 no.4
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• pp.373-383
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• 2024

Background: Network pharmacology has emerged as a powerful tool to understand the therapeutic effects and mechanisms of natural products. However, there is a lack of comprehensive evaluations of network-based approaches for natural products on identifying therapeutic effects and key mechanisms. Purpose: We systematically explore the capabilities of network-based approaches on natural products, using Panax ginseng as a case study. P. ginseng is a widely used herb with a variety of therapeutic benefits, but its active ingredients and mechanisms of action on chronic diseases are not yet fully understood. Methods: Our study compiled and constructed a network focusing on P. ginseng by collecting and integrating data on ingredients, protein targets, and known indications. We then evaluated the performance of different network-based methods for summarizing known and unknown disease associations. The predicted results were validated in the hepatic stellate cell model. Results: We find that our multiscale interaction-based approach achieved an AUROC of 0.697 and an AUPR of 0.026, which outperforms other network-based approaches. As a case study, we further tested the ability of multiscale interactome-based approaches to identify active ingredients and their plausible mechanisms for breast cancer and liver cirrhosis. We also validated the beneficial effects of unreported and top-predicted ingredients, in cases of liver cirrhosis and gastrointestinal neoplasms. Conclusion: our study provides a promising framework to systematically explore the therapeutic effects and key mechanisms of natural products, and highlights the potential of network-based approaches in natural product research.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.544-552
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• 2004

This paper deals with the hybrid active filter which can reduce the 11th/13th harmonics in AC network by using the single tuned filter. Since the proposed algorithm uses the detuning compensation capability of the filter, the output voltage of the proposed active power filter is changed according to the capacitance of capacitors, magnitude of harmonic current, resonance frequency and control mode. In this paper, the control characteristics and the design of hybrid active filter is investigated. A new hybrid active filter with new algorithm, which is an active filter with single tuned filter instead of double tuned filter, is proposed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.3
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• pp.31-38
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• 2010

It has become more difficult to correspond an cyber attack quickly as patterns of attack become various and complex. However, current security mechanisms just have passive defense functionalities. In this paper, we propose new network security architecture to respond various cyber attacks rapidly and to chase and isolate the attackers through cooperation between security zones. The proposed architecture makes it possible to deal effectively with cyber attacks such as IP spoofing or DDoS(Distributed Denial of Service), by using active packet technology including a mobile code on active network. Also, it is designed to have more active correspondent than that of existing mechanisms. We implemented these mechanisms in Linux routers and experimented on a testbed to verify realization possibility of attacker response framework using mobile code. The experimentation results are analyzed.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.959-970
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• 2004

It has become more difficult to correspond an cyber attack quickly as patterns of attack become various and complex. However, current so curity mechanisms just have passive defense functionalities. In this paper, we propose new network suity architecture to respond various cyber attacks rapidly and to chase and isolate the attackers through cooperation between security zones. The proposed architecture makes it possible to deal effectively with cyber attacks such as IP spoofing or DDoS(Distributed Denial of Service), by using active packet technology including a mobile code on active network. Also, it is designed to have more active correspondent than that of existing mechanisms. We im-plemented these mechanisms in Linux routers and experimented on a testbed to verify realization possibility of attacker response framework using mobile code. The experimentation results are analyzed.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.229-237
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• 2005

One of the important issues of in this research is effective usage of energy to increase life time of nodes which form a network. Existing LEEM protocol causes unnecessary active time due to small packets with shorter transfer time than active interval period of node and packets with transfer time of more than twice of active interval period of node. In this paper, we propose Energy-Efficient MAC by Reservation (EEMR) protocol which can increase energy effectiveness in wireless sensor network environment by reducing unnecessary active time using a method that reserves next-hop depend upon the size of packet. We evaluated effectiveness of our proposed method through experiments. The result showed that using EEMR protocol had better energy effectiveness than existing LEEM protocol by 15%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5140-5147
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• 2013

This paper presents a new idea of structural design of the optical access network for IPOW(IP over WDM) services. More efficient network can be constructed, because the IP packets are transmitted directly to the WDM without going through an intermediate layer of networks. The wavelength Routing is based on a label switching technology. The ability to transmission of high volume traffics and QoS capability of the optical label switching directly to the end user of the IPOW optical internet networks is provided. As in AON(Active Optical Network) flexible bandwidth on demand subscribers is allocated. By the Simulation of the proposed optical access networks to measure the BER(Bits Error Ratio) at the end of the nodes the network characteristics are analyzed. These results are based on the design of efficient optical network.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.142-155
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• 2000

A MIMO model reference control scheme incorporating the variable structure theory for a vehicle four wheel steering system(4WS) is proposed and evaluated for a class of continuous-time nonlinear dynamics with known or unknown uncertainties. The scheme employs an neural network to identify the plant systems, where the neural network estimates the nonlinear dynamics of the plant. By the Lyapunov direct method, the algorithm is proven to be globally stable, with tracking errors converging to the neighborhood of zero. The merits of this scheme is that the global system stability is guaranteed and it is not necessary to know the exact structure of the system. With the resulting identification model which contains the neural networks, it does not need higher degrees of freedom vehicle model than 3 degree of freedom model. Th proposed scheme is applied to the active four wheel system and shows the validity is used to investigate vehicle handing performances. In simulation of the J-turn maneuver, the reduction of yaw rate overshoot of a typical mid-size car improved by 30% compared to a two wheel steering system(2WS) case, resulting that the proposed scheme gives faster yaw rate response and smaller side angle than the 2WS case.

• Smart Structures and Systems
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• v.11 no.3
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• pp.315-329
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• 2013

The construction of an experimental nonlinear structural model with little cost and unlimited repeatability for vibration control study represents a challenging task, especially for material nonlinearity. This paper reports the design, analysis and vibration control of a nonlinear structural experiment platform with adjustable hinges. In our approach, magnetorheological rotary brakes are substituted for the joints of a frame structure to simulate the nonlinear material behaviors of plastic hinges. For vibration control, a separate magnetorheological damper was employed to provide semi-active damping force to the nonlinear structure. A dynamic neural network was designed as a state observer to enable the feedback based semi-active vibration control. Based on the dynamic neural network observer, an adaptive fuzzy sliding mode based output control was developed for the magnetorheological damper to suppress the vibrations of the structure. The performance of the intelligent control algorithm was studied by subjecting the structure to shake table experiments. Experimental results show that the magnetorheological rotary brake can simulate the nonlinearity of the structural model with good repeatability. Moreover, different nonlinear behaviors can be achieved by controlling the input voltage of magnetorheological rotary damper. Different levels of nonlinearity in the vibration response of the structure can be achieved with the above adaptive fuzzy sliding mode control algorithm using a dynamic neural network observer.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.12
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• pp.1220-1225
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• 2010

This paper proposes a novel active noise control (ANC) approach that uses an IIR filter and neural network techniques to effectively reduce interior noise. We construct a multiple-channel IIR filter module which is a linearly augmented framework with a generic IIR model to generate a primary control signal. A three-layer perceptron neural network is employed for establishing a secondary-path model to represent air channels among noise fields. Since the IIR module and neural network are connected in series, the output of an IIR filter is transferred forward to the neural model to generate a final ANC signal. A gradient descent optimization based learning algorithm is analytically derived for the optimal selection of the ANC parameter vectors. Moreover, re-estimation of partial parameter vectors in the ANC system is proposed for online learning. Lastly, we present the results of a numerical study to test our ANC methodology with realistic interior noise measurement obtained from Korean railway trains.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.340-350
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• 2016

The performance of large-scale cognitive radio (CR) networks with secondary users sustained by opportunistically harvesting radio-frequency (RF) energy from nearby primary transmissions is investigated. Using an advanced RF energy harvester, a secondary user is assumed to be able to collect ambient primary RF energy as long as it lies inside the harvesting zone of an active primary transmitter (PT). A variable power (VP) transmission mode is proposed, and an energy-based opportunistic spectrum access (OSA) strategy is considered, under which a secondary transmitter (ST) is allowed to transmit only if its harvested energy is larger than a predefined transmission threshold and it is outside the guard zones of all active PTs. The transmission probability of the STs is derived. The outage probabilities and the throughputs of the primary and the secondary networks, respectively, are characterized. Compared with prior work, the throughput can be increased by as much as 29%. The energy-based OSA strategy can be generally applied to a non-CR setup, where distributed power beacons (PBs) are deployed to power coexisting wireless signal transmitters (WSTs) in a wireless powered sensor network.