• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1785-1801
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• 2017

In recent years, image encryption algorithms have been developed rapidly in order to ensure the security of image transmission. With the assistance of our previous work, this paper proposes a novel chaotic image encryption algorithm based on self-adaptive model and feedback mechanism to enhance the security and improve the efficiency. Different from other existing methods where the permutation is performed by the self-adaptive model, the initial values of iteration are generated in a novel way to make the distribution of initial values more uniform. Unlike the other schemes which is on the strength of the feedback mechanism in the stage of diffusion, the piecewise linear chaotic map is first introduced to produce the intermediate values for the sake of resisting the differential attack. The security and efficiency analysis has been performed. We measure our scheme through comprehensive simulations, considering key sensitivity, key space, encryption speed, and resistance to common attacks, especially differential attack.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.3
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• pp.79-90
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• 2004

Systematical robust stability analysis and design scheme for the feedback linearization control systems via fuzzy modeling are proposed. It is considered that uncertainty and disturbances are included in the Takagi-Sugeno fuzzy models representing the nonlinear plants. Robust stability of the closed system is analyzed by casting the systems into the diagonal norm bounded linear differential inclusions and by converting the analysis and design problems into the linear matrix inequality optimization, a numerical method for finding the maximum stable ranges of the fuzzy feedback linearization control gains is also proposed. To verify the effectiveness of the proposed scheme, the robust stability analysis and control design examples are given.

• Communications of the Korean Mathematical Society
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• v.19 no.3
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• pp.557-567
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• 2004

We prove the sufficient conditions for optimality in differential inclusion problem by using the value function. For this purpose, we assume at first that the value function is locally Lipschitz. Secondly, without this assumption, we use the viability theory.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.379-379
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• 1998

The report presents an approach to constructing or control algorithms for finite dimensional dynamical systems under the deficit of information about dynamical disturbances. The approach is based on the constructions of the extremal shift strategy of the differential game theory.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1977-1978
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• 2008

In this paper, we compare performance of common-mode rejection between a differential and a non-differential amplifier system with two electrodes. A differential amplifier system is constant for common-mode rejection ratio(CMRR) on the frequency domain. But a non-differential amplifier's CMRR is determined by $Z_{FB}/Z_e$ ($Z_{FB}$ ; feedback impedance, $Z_e$; electrode impedance). There is trade-off between a non-differential amplifier's CMRR and its differential input impedance. And a non-differential amplifier system has some advantages for a bio-potential measurement with two electrodes because a designer can control the impedance between the body and system's common.

• Bulletin of the Korean Mathematical Society
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• v.35 no.2
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• pp.325-338
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• 1998

Some nonlocal boundary value problems which arise from a feedback control problem are considered. We give a precise statement of the mathematical problems and then prove the existence and uniqueness of the solutions. We consider the Dirichlet type boundary value problem and the Neumann type boundary value problem with nonlinear boundary conditions. We also provide a regularity results for the solutions.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.397-400
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• 2002

In this paper, a novel noncoherent multiuser detector with diversity reception for a differentially encoded DS/CDMA signal in a frequency-selective Rayleigh fading channel is proposed. The proposed receiver employs multipath decorrelator and decision feedback differential detector (DFDD) with diversity reception. DFDD performs differential encoding and diversity combining. The performance is obtained by analysis and simulation and it is sown that the proposed receiver outperforms conventional differential receiver with slight increase of complexity.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.58-65
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• 2022

Objective: The purpose of this study was to investigate the effect of visual feedback bicycle training on running performance, maximal oxygen uptake and quadriceps muscle strength. Design: A randomized controlled trial. Methods: Fifteen healthy adult men with no musculoskeletal or nervous system disease and capable of bicycle training were included. After the pretest, subjects were randomly assigned to visual feedback bicycle training group and general fixed bicycle training group. Both groups were trained two times a week for three weeks, each week for a fixed time and number of repetitions, followed by a six week washout period and then crossing the training method. visual feedback bicycle training provides visual feedback of heart rate in real time using a monitor and a heart rate meter during bicycle training, and general fixed bicycle training performed general bicycle training without visual feedback. After training, each item was measured using a wearable technology, gas analyzer, isokinetic equipment. Results: The results of this study was significant differences in running performance, maximal oxygen uptake and quadriceps muscle strength in visual feedback bicycle training group (p<0.05). The differential effect was found between visual feedback bicycle training group and general fixed bicycle training group in running performance, maximal oxygen uptake, and quadriceps muscle strength (p<0.05). Conclusions: This study suggested that that visual feedback bicycle training can be applied as a useful training method to improve running performance, maximal oxygen uptake and quadriceps muscle strength.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.5
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• pp.31-41
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• 1995

In this paper, the relationship between k consecutive outputs of the conventional differential detector and output of differential detector with k-symbol periods delay for differential MSK and GMSK systems is investigated. It is hown that there exists periodity in modulo-2 sum and product of k successive outputs of the conventional differential detector with the output of a detector with k-symbol periods delay circuit. This relationships are used to achieve performance gains over conventional differential detection. The error rate performance of the method is carried out by computer simulation and performance improvement is achieved for differential MSK and GMSK systems.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1193-1204
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• 2011

In the present paper we consider a differential-algebraic prey-predator model with stage structure for prey and harvesting of predator species. Stability and instability of the equilibrium points are discussed and it is observed that the model exhibits a singular induced bifurcation when the economic profit is zero. It indicates that the zero economic profit brings impulse, i.e. rapid expansion of the population and the system collapses. For the purpose of stabilizing the system around the positive equilibrium, a state feedback controller is designed. Finally, numerical simulations are given to show the consistency with theoretical analysis.