The Experts below are selected from a list of 71046 Experts worldwide ranked by ideXlab platform

Abir Mhenni - One of the best experts on this subject based on the ideXlab platform.

  • double serial Adaptation Mechanism for keystroke dynamics authentication based on a single password
    Computers & Security, 2019
    Co-Authors: Abir Mhenni, Estelle Cherrier, Christophe Rosenberger, Najoua Essoukri Ben Amara
    Abstract:

    Abstract Cyber-attacks have spread all over the world to steal information such as trade secrets, intellectual property and banking data. Facing the danger of the insecurity of saved data (personal, professional, official, etc.), keystroke dynamics was proposed as an interesting, non-intrusive, inexpensive, permanent and weakly constrained solution for users. Based on the typing rhythm of users, it improves logical access security. Nevertheless, it was demonstrated that such an authentication Mechanism would need a larger number of samples to enroll the typing characteristics of users. Moreover, these registered characteristics generally undergo aging effects after a time span. Different solutions have been suggested to remedy these variability problems, including template Adaptation. In this paper, we propose a double serial Adaptation strategy that considers a single-capture-based enrollment process. When using the authentication system, the template of users and the decision/Adaptation thresholds are updated. Experimental results on three public keystroke dynamics datasets show the benefits of the proposed method.

Shiva S Kumar - One of the best experts on this subject based on the ideXlab platform.

  • type 2 fuzzy logic control based mras speed estimator for speed sensorless direct torque and flux control of an induction motor drive
    Isa Transactions, 2015
    Co-Authors: Tejavathu Ramesh, Anup Kumar Panda, Shiva S Kumar
    Abstract:

    In this research study, a model reference adaptive system (MRAS) speed estimator for speed sensorless direct torque and flux control (DTFC) of an induction motor drive (IMD) using two Adaptation Mechanism schemes are proposed to replace the conventional proportional integral controller (PIC). The first Adaptation Mechanism scheme is based on Type-1 fuzzy logic controller (T1FLC), which is used to achieve high performance sensorless drive in both transient as well as steady state conditions. However, the Type-1 fuzzy sets are certain and unable to work effectively when higher degree of uncertainties presents in the system which can be caused by sudden change in speed or different load disturbances, process noise etc. Therefore, a new Type-2 fuzzy logic controller (T2FLC) based Adaptation Mechanism scheme is proposed to better handle the higher degree of uncertainties and improves the performance and also robust to various load torque and sudden change in speed conditions, respectively. The detailed performances of various Adaptation Mechanism schemes are carried out in a MATLAB/Simulink environment with a speed sensor and speed sensorless modes of operation when an IMD is operating under different operating conditions, such as, no-load, load and sudden change in speed, respectively. To validate the different control approaches, the system also implemented on real-time system and adequate results are reported for its validation.

  • mras speed estimator based on type 1 and type 2 fuzzy logic controller for the speed sensorless dtfc svpwm of an induction motor drive
    Journal of Power Electronics, 2015
    Co-Authors: Tejavathu Ramesh, Anup Kumar Panda, Shiva S Kumar
    Abstract:

    This paper presents model reference adaptive system speed estimators based on Type-1 and Type-2 fuzzy logic controllers for the speed sensorless direct torque and flux control of an induction motor drive (IMD) using space vector pulse width modulation. A Type-1 fuzzy logic controller (T1FLC) based Adaptation Mechanism scheme is initially presented to achieve high performance sensorless drive in both transient as well as in steady-state conditions. However, the Type-1 fuzzy sets are certain and cannot work effectively when a higher degree of uncertainties occurs in the system, which can be caused by sudden changes in speed or different load disturbances and, process noise. Therefore, a new Type-2 FLC (T2FLC) - based Adaptation Mechanism scheme is proposed to better handle the higher degree of uncertainties, improve the performance, and is also robust to different load torque and sudden changes in speed conditions. The detailed performance of different Adaptation Mechanism schemes are performed in a MATLAB/Simulink environment with a speed sensor and sensorless modes of operation when an IMD is operates under different operating conditions, such as no-load, load, and sudden changes in speed. To validate the different control approaches, the system is also implemented on a real-time system, and adequate results are reported for its validation.

Micaela Carvajal - One of the best experts on this subject based on the ideXlab platform.

  • changes in plasma membrane lipids aquaporins and proton pump of broccoli roots as an Adaptation Mechanism to salinity
    Phytochemistry, 2009
    Co-Authors: Luis Lopezperez, Maria Del Carmen Martinezballesta, Christophe Maurel, Micaela Carvajal
    Abstract:

    + -ATPase abstract Salinity stress is known to modify the plasma membrane lipid and protein composition of plant cells. In this work, we determined the effects of salt stress on the lipid composition of broccoli root plasma mem- brane vesicles and investigated how these changes could affect water transport via aquaporins. Brassica oleracea L. var. Italica plants treated with different levels of NaCl (0, 40 or 80 mM) showed significant dif- ferences in sterol and fatty acid levels. Salinity increased linoleic (18:2) and linolenic (18:3) acids and stigmasterol, but decreased palmitoleic (16:1) and oleic (18:1) acids and sitosterol. Also, the unsaturation index increased with salinity. Salinity increased the expression of aquaporins of the PIP1 and PIP2 sub- families and the activity of the plasma membrane H + -ATPase. However, there was no effect of NaCl on water permeability (Pf) values of root plasma membrane vesicles, as determined by stopped-flow light scattering. The counteracting changes in lipid composition and aquaporin expression observed in NaCl- treated plants could allow to maintain the membrane permeability to water and a higher H

  • Changes in plasma membrane lipids, aquaporins and proton pump of broccoli roots, as an Adaptation Mechanism to salinity.
    Phytochemistry, 2009
    Co-Authors: Luis López-pérez, Christophe Maurel, María Del Carmen Martínez-ballesta, Micaela Carvajal
    Abstract:

    Salinity stress is known to modify the plasma membrane lipid and protein composition of plant cells. In this work, we determined the effects of salt stress on the lipid composition of broccoli root plasma membrane vesicles and investigated how these changes could affect water transport via aquaporins. Brassica oleracea L. var. Italica plants treated with different levels of NaCl (0, 40 or 80mM) showed significant differences in sterol and fatty acid levels. Salinity increased linoleic (18:2) and linolenic (18:3) acids and stigmasterol, but decreased palmitoleic (16:1) and oleic (18:1) acids and sitosterol. Also, the unsaturation index increased with salinity. Salinity increased the expression of aquaporins of the PIP1 and PIP2 subfamilies and the activity of the plasma membrane H(+)-ATPase. However, there was no effect of NaCl on water permeability (P(f)) values of root plasma membrane vesicles, as determined by stopped-flow light scattering. The counteracting changes in lipid composition and aquaporin expression observed in NaCl-treated plants could allow to maintain the membrane permeability to water and a higher H(+)-ATPase activity, thereby helping to reduce partially the Na(+) concentration in the cytoplasm of the cell while maintaining water uptake via cell-to-cell pathways. We propose that the modification of lipid composition could affect membrane stability and the abundance or activity of plasma membrane proteins such as aquaporins or H(+)-ATPase. This would provide a Mechanism for controlling water permeability and for acclimation to salinity stress.

Tejavathu Ramesh - One of the best experts on this subject based on the ideXlab platform.

  • type 2 fuzzy logic control based mras speed estimator for speed sensorless direct torque and flux control of an induction motor drive
    Isa Transactions, 2015
    Co-Authors: Tejavathu Ramesh, Anup Kumar Panda, Shiva S Kumar
    Abstract:

    In this research study, a model reference adaptive system (MRAS) speed estimator for speed sensorless direct torque and flux control (DTFC) of an induction motor drive (IMD) using two Adaptation Mechanism schemes are proposed to replace the conventional proportional integral controller (PIC). The first Adaptation Mechanism scheme is based on Type-1 fuzzy logic controller (T1FLC), which is used to achieve high performance sensorless drive in both transient as well as steady state conditions. However, the Type-1 fuzzy sets are certain and unable to work effectively when higher degree of uncertainties presents in the system which can be caused by sudden change in speed or different load disturbances, process noise etc. Therefore, a new Type-2 fuzzy logic controller (T2FLC) based Adaptation Mechanism scheme is proposed to better handle the higher degree of uncertainties and improves the performance and also robust to various load torque and sudden change in speed conditions, respectively. The detailed performances of various Adaptation Mechanism schemes are carried out in a MATLAB/Simulink environment with a speed sensor and speed sensorless modes of operation when an IMD is operating under different operating conditions, such as, no-load, load and sudden change in speed, respectively. To validate the different control approaches, the system also implemented on real-time system and adequate results are reported for its validation.

  • mras speed estimator based on type 1 and type 2 fuzzy logic controller for the speed sensorless dtfc svpwm of an induction motor drive
    Journal of Power Electronics, 2015
    Co-Authors: Tejavathu Ramesh, Anup Kumar Panda, Shiva S Kumar
    Abstract:

    This paper presents model reference adaptive system speed estimators based on Type-1 and Type-2 fuzzy logic controllers for the speed sensorless direct torque and flux control of an induction motor drive (IMD) using space vector pulse width modulation. A Type-1 fuzzy logic controller (T1FLC) based Adaptation Mechanism scheme is initially presented to achieve high performance sensorless drive in both transient as well as in steady-state conditions. However, the Type-1 fuzzy sets are certain and cannot work effectively when a higher degree of uncertainties occurs in the system, which can be caused by sudden changes in speed or different load disturbances and, process noise. Therefore, a new Type-2 FLC (T2FLC) - based Adaptation Mechanism scheme is proposed to better handle the higher degree of uncertainties, improve the performance, and is also robust to different load torque and sudden changes in speed conditions. The detailed performance of different Adaptation Mechanism schemes are performed in a MATLAB/Simulink environment with a speed sensor and sensorless modes of operation when an IMD is operates under different operating conditions, such as no-load, load, and sudden changes in speed. To validate the different control approaches, the system is also implemented on a real-time system, and adequate results are reported for its validation.

Najoua Essoukri Ben Amara - One of the best experts on this subject based on the ideXlab platform.

  • double serial Adaptation Mechanism for keystroke dynamics authentication based on a single password
    Computers & Security, 2019
    Co-Authors: Abir Mhenni, Estelle Cherrier, Christophe Rosenberger, Najoua Essoukri Ben Amara
    Abstract:

    Abstract Cyber-attacks have spread all over the world to steal information such as trade secrets, intellectual property and banking data. Facing the danger of the insecurity of saved data (personal, professional, official, etc.), keystroke dynamics was proposed as an interesting, non-intrusive, inexpensive, permanent and weakly constrained solution for users. Based on the typing rhythm of users, it improves logical access security. Nevertheless, it was demonstrated that such an authentication Mechanism would need a larger number of samples to enroll the typing characteristics of users. Moreover, these registered characteristics generally undergo aging effects after a time span. Different solutions have been suggested to remedy these variability problems, including template Adaptation. In this paper, we propose a double serial Adaptation strategy that considers a single-capture-based enrollment process. When using the authentication system, the template of users and the decision/Adaptation thresholds are updated. Experimental results on three public keystroke dynamics datasets show the benefits of the proposed method.