• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1632-1636
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• 2005

This paper presents synchronization of two identical Modified Chua's circuits using two strategies of error feedback coupling. In the first method the synchronization is achieved by linear unidirectional and in the second one by linear bidirectional error feedback coupling. Both proposed methods can make the states of the Modified Chua's circuits globally asymptotically synchronized. Numerical results are provided to show the effectiveness of the proposed approaches and to compare them together based on different criteria.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1419-1424
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• 2005

This paper suggests a new cipher mode of operation which can recover cryptographic synchronization. First, we study the typical cipher modes of operation, especially focused on cryptographic synchronization problems. Then, we suggest a statistical cipher-feedback mode of operation. We define the error sources mathmatically and simulate propagation errors caused by a bit insertion or bit deletion. In the simulation, we compare the effects of changing the synchronization pattern length and feedback key length. After that, we analyze the simulation results with the calculated propagation errors. finally. we evaluate the performance of the statistical cipher-feedback mode of operation and recommand the implementation considerations.

• Kyungpook Mathematical Journal
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• v.54 no.2
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• pp.293-320
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• 2014

In this paper, global chaos synchronization is investigated for WINDMI (J. C. Sprott, 2003) and Coullet (P. Coullet et al, 1979) chaotic systems using adaptive backstepping control design based on recursive feedback control. Our theorems on synchronization for WINDMI and Coullet chaotic systems are established using Lyapunov stability theory. The adaptive backstepping control links the choice of Lyapunov function with the design of a controller and guarantees global stability performance of strict-feedback chaotic systems. The adaptive backstepping control maintains the parameter vector at a predetermined desired value. The adaptive backstepping control method is effective and convenient to synchronize and estimate the parameters of the chaotic systems. Mainly, this technique gives the flexibility to construct a control law and estimate the parameter values. Numerical simulations are also given to illustrate and validate the synchronization results derived in this paper.

• Journal of Drive and Control
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• v.10 no.3
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• pp.14-20
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• 2013

In the study, a control strategy using a feedback linearization compensator and a disturbance observer was suggested and applied to the synchronization control of two hydraulic cylinders. The hydraulic system consists of a proportional directional control valve with overlap characteristic near the neutral position, a conventional hydraulic cylinder and an external load. The control performances of the system were verified through numerical simulations. From the simulations, it was ascertained that excellent control performances were obtained with the suggested control strategy.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.953-960
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• 2002

Rel-time application programs have constraints which need to be met between media-data. It is client-leading synchronization that is absorbing variable transmission delay time and that is synchronizing by feedback control and palyout control. It is the important factor for playback rate and QoS if the buffer level is normal or not. This paper, The method of maintenance buffer normal state transmits in multimedia server by appling feedback of filtering function. And synchronization method is processing adaptive playout time for smooth presentation without cut-off while media frame is skip. When audio frame which is master media is in upper threshold buffer level we decrease play out time gradually, low threshold buffer level increase it slowly.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4342-4366
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• 2016

Congestion control in Cluster Wireless Sensor Networks (CWSNs) has drawn widespread attention and research interests. The increasing number of nodes and scale of networks cause more complex congestion control and management. Active Queue Management (AQM) is one of the major congestion control approaches in CWSNs, and Random Early Detection (RED) algorithm is commonly used to achieve high utilization in AQM. However, traditional RED algorithm depends exclusively on source-side control, which is insufficient to maintain efficiency and state stability. Specifically, when congestion occurs, deficiency of feedback will hinder the instability of the system. In this paper, we adopt the Additive-Increase Multiplicative-Decrease (AIMD) adjustment scheme and propose an improved RED algorithm by using neighbor feedback and scheduling scheme. The congestion control model is presented, which is a linear system with a non-linear feedback, and modeled by Lur'e type system. In the context of delayed Lur'e dynamical network, we adopt the concept of cluster synchronization and show that the congestion controlled system is able to achieve cluster synchronization. Sufficient conditions are derived by applying Lyapunov-Krasovskii functionals. Numerical examples are investigated to validate the effectiveness of the congestion control algorithm and the stability of the network.

• Journal of the Korea Computer Industry Society
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• v.3 no.9
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• pp.1251-1260
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• 2002

Real-time application programs have synchronization constraints which need to be met between media-data. Synchronization method represents feedback method including virtual client-side buffer. This buffer is used in buffer level method. It is client-leading synchronization that is absorbing variable transmission delay time and that is synchronizing by feedback control. It is the important factor for playback rate and QoS if the buffer level is normal or not. To solve the problems, we can control the start of transmission in multimedia server by appling filtering, control and network evaluation function. Synchronization method is processing for smooth presentation without cut-off while media is playing out. When audio frame which is master media is in high threshold buffer level we decrease play out time gradually, otherwise we increase it slowly.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.11
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• pp.963-968
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• 2003

A feedback control implementation for a high speed train pressurization system is proposed based on CAN (Controller Area Network). Firstly, system model including network latencies by CAN arbitration mechanisms is proposed, and an analytical compensation method of control parameters based on the system model is proposed for the network latencies. For the practical implementation of the control, global synchronization is adopted for controller to measure network latencies and to utilize them for the compensation of the control parameters. Simulation results are shown with practical tunnel data response. The proposed method is evaluated to be the most effective for the system through the control performances comparing among a controller not considering network latencies, other two off-line compensation methods, and the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6A
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• pp.468-475
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• 2009

In OFDM-based Full Duplex Relays (FDR) with Decode and Forward (DF) scheme, an interference cancellation technique in the frequency domain is more efficient than the one in the time domain. However, an Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) may occur due to the timing mismatch between the feedback interference signal and the desired signal from Base Station (BS) when the feedback interference cancellation and demodulation are performed in the frequency domain. In this paper, the effects of timing mismatch on the synchronous type and asynchronous type of OFDM-based FDR are analyzed for uplink and downlink cases. Then, synchronization procedure and methods for reducing ISI and ICI in OFDM-based FDR with frequency-domain feedback interference canceller are proposed and verified by computer simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1011-1016
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• 2018

Ubiquitous services for the convenience and safety of human beings along with the development of society are being realized through RFID technology and sensor network, and its application range of fields is also broaden. However, since the USN contains all the information of individuals and things, all of its private spaces can be attacked by external attacks; so, that the problem of security continues to arise. We designed a one-way chaotic feedback synchronization method as a secure communication method to fit the USN composed of one sync node and n number of sensor nodes. We designed the method by which the sensor node is synchronized in one direction of the sync node. This method solves the problem that all sensor nodes need to be resynchronized when the sync node is changed, which is shown in bidirectional synchronization. This is a security method that can be effectively applied to 1:n communication such as USN.