The Experts below are selected from a list of 129246 Experts worldwide ranked by ideXlab platform
Chaogan Yan - One of the best experts on this subject based on the ideXlab platform.
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the Subsystem mechanism of default mode network underlying rumination a reproducible neuroimaging study
NeuroImage, 2020Co-Authors: Xiao Chen, Ningxuan Chen, Yangqian Shen, Zhichen Zhu, Zhen Fan, Chaogan YanAbstract:Rumination is a repetitive self-referential thinking style that is often interpreted as an expression of abnormalities of the default mode network (DMN) observed during "resting-state" in major depressive disorder (MDD). Recent evidence has demonstrated that the DMN is not unitary but can be further divided into 3 functionally heterogenous Subsystems, although the Subsystem mechanistically underlying rumination remains unclear. Due to the unconstrained and indirect correlational nature of previous resting-state fMRI studies on rumination's network underpinnings, a paradigm allowing direct investigation of network interactions during active rumination is needed. Here, with a modified continuous state-like paradigm, we induced healthy participants to ruminate or imagine objective scenarios (distraction, as a control condition) on 3 different MRI scanners. We compared functional connectivities (FC) of the DMN and its 3 Subsystems between rumination and distraction states. Results yielded a highly reproducible and dissociated pattern. During rumination, within-DMN FC was generally decreased as compared to the distraction state. At the Subsystem level, we found increased FC between the core and medial temporal lobe (MTL) Subsystem as well as decreased FC between the core and dorsal medial prefrontal cortex (DMPFC) Subsystem and within the MTL Subsystem. Finally, subjects' behavioral measures of rumination and brooding were negatively correlated with FC between the core and DMPFC Subsystems. These results suggest active rumination involves enhanced constraint by the core Subsystem on the MTL Subsystem and decreased coupling between the core and DMPFC Subsystem, allowing for more information exchange among those involved DMN components. Furthermore, the reproducibility of our findings provides a rigorous evaluation of their validity and significance.
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the Subsystem mechanism of default mode network underlying rumination a reproducible neuroimaging study
bioRxiv, 2020Co-Authors: Xiao Chen, Ningxuan Chen, Yangqian Shen, Zhichen Zhu, Zhen Fan, Chaogan YanAbstract:Rumination is a repetitive self-referential thinking style and posited to be an expression of abnormalities in the default mode network (DMN) in major depressive disorder (MDD). Recent evidences indicate DMN is not a unitary network but can be further divided into 3 functionally heterogenous Subsystems. However, the Subsystem mechanism through which DMN underlie rumination remain unclear. Here, with a modified continuous state-like paradigm, we induced healthy participants to ruminate or imagine objective scenarios (as a distraction control condition) on 3 different MRI scanners. We compared functional connectivities (FC) and inter-subject correlations (ISC) of the DMN and its 3 Subsystems between rumination and distraction states. Results yielded a highly reproducible and dissociated pattern. During rumination, within-DMN FC was generally decreased compared to the distraction state. At the Subsystem level, we found increased FC between the core and medial temporal lobe (MTL) Subsystem and decreased FC between the core and dorsal medial prefrontal cortex (DMPFC) Subsystem and within the MTL Subsystem. Furthermore, we found decreased ISC within the MTL Subsystem. These results suggest a specific and less synchronous activity pattern of DMN during rumination and shed new light on the association between rumination and DMN substrates regarding MDD.
Karl Henrik Johansson - One of the best experts on this subject based on the ideXlab platform.
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composability and controllability of structural linear time invariant systems distributed verification
Automatica, 2017Co-Authors: Frederico J Carvalho, Sergio Pequito, Pedro A Aguiar, Karl Henrik JohanssonAbstract:Abstract Motivated by the development and deployment of large-scale dynamical systems, often comprised of geographically distributed smaller Subsystems, we address the problem of verifying their controllability in a distributed manner. Specifically, we study controllability in the structural system theoretic sense, structural controllability, in which rather than focusing on a specific numerical system realization, we provide guarantees for equivalence classes of linear time-invariant systems on the basis of their structural sparsity patterns, i.e., the location of zero/nonzero entries in the plant matrices. Towards this goal, we first provide several necessary and/or sufficient conditions that ensure that the overall system is structurally controllable on the basis of the Subsystems’ structural pattern and their interconnections. The proposed verification criteria are shown to be efficiently implementable (i.e., with polynomial time-complexity in the number of the state variables and inputs) in two important subclasses of interconnected dynamical systems: similar (where every Subsystem has the same structure) and serial (where every Subsystem outputs to at most one other Subsystem). Secondly, we provide an iterative distributed algorithm to verify structural controllability for general interconnected dynamical system, i.e., it is based on communication among (physically) interconnected Subsystems, and requires only local model and interconnection knowledge at each Subsystem.
Xiao Chen - One of the best experts on this subject based on the ideXlab platform.
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the Subsystem mechanism of default mode network underlying rumination a reproducible neuroimaging study
NeuroImage, 2020Co-Authors: Xiao Chen, Ningxuan Chen, Yangqian Shen, Zhichen Zhu, Zhen Fan, Chaogan YanAbstract:Rumination is a repetitive self-referential thinking style that is often interpreted as an expression of abnormalities of the default mode network (DMN) observed during "resting-state" in major depressive disorder (MDD). Recent evidence has demonstrated that the DMN is not unitary but can be further divided into 3 functionally heterogenous Subsystems, although the Subsystem mechanistically underlying rumination remains unclear. Due to the unconstrained and indirect correlational nature of previous resting-state fMRI studies on rumination's network underpinnings, a paradigm allowing direct investigation of network interactions during active rumination is needed. Here, with a modified continuous state-like paradigm, we induced healthy participants to ruminate or imagine objective scenarios (distraction, as a control condition) on 3 different MRI scanners. We compared functional connectivities (FC) of the DMN and its 3 Subsystems between rumination and distraction states. Results yielded a highly reproducible and dissociated pattern. During rumination, within-DMN FC was generally decreased as compared to the distraction state. At the Subsystem level, we found increased FC between the core and medial temporal lobe (MTL) Subsystem as well as decreased FC between the core and dorsal medial prefrontal cortex (DMPFC) Subsystem and within the MTL Subsystem. Finally, subjects' behavioral measures of rumination and brooding were negatively correlated with FC between the core and DMPFC Subsystems. These results suggest active rumination involves enhanced constraint by the core Subsystem on the MTL Subsystem and decreased coupling between the core and DMPFC Subsystem, allowing for more information exchange among those involved DMN components. Furthermore, the reproducibility of our findings provides a rigorous evaluation of their validity and significance.
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the Subsystem mechanism of default mode network underlying rumination a reproducible neuroimaging study
bioRxiv, 2020Co-Authors: Xiao Chen, Ningxuan Chen, Yangqian Shen, Zhichen Zhu, Zhen Fan, Chaogan YanAbstract:Rumination is a repetitive self-referential thinking style and posited to be an expression of abnormalities in the default mode network (DMN) in major depressive disorder (MDD). Recent evidences indicate DMN is not a unitary network but can be further divided into 3 functionally heterogenous Subsystems. However, the Subsystem mechanism through which DMN underlie rumination remain unclear. Here, with a modified continuous state-like paradigm, we induced healthy participants to ruminate or imagine objective scenarios (as a distraction control condition) on 3 different MRI scanners. We compared functional connectivities (FC) and inter-subject correlations (ISC) of the DMN and its 3 Subsystems between rumination and distraction states. Results yielded a highly reproducible and dissociated pattern. During rumination, within-DMN FC was generally decreased compared to the distraction state. At the Subsystem level, we found increased FC between the core and medial temporal lobe (MTL) Subsystem and decreased FC between the core and dorsal medial prefrontal cortex (DMPFC) Subsystem and within the MTL Subsystem. Furthermore, we found decreased ISC within the MTL Subsystem. These results suggest a specific and less synchronous activity pattern of DMN during rumination and shed new light on the association between rumination and DMN substrates regarding MDD.
Babatunde A Ogunnaike - One of the best experts on this subject based on the ideXlab platform.
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a hybrid model predictive control strategy for nonlinear plant wide control
Journal of Process Control, 2000Co-Authors: Guangyan Zhu, Michael A Henson, Babatunde A OgunnaikeAbstract:Abstract A plant-wide control strategy based on integrating linear model predictive control (LMPC) and nonlinear model predictive control (NMPC) is proposed. The hybrid method is applicable to plants that can be decomposed into approximately linear Subsystems and highly nonlinear Subsystems that interact via mass and energy flows. LMPC is applied to the linear Subsystems and NMPC is applied to the nonlinear Subsystems. A simple controller coordination strategy that counteracts interaction effects is proposed for the case of one linear Subsystem and one nonlinear Subsystem. A reactor/separator process with recycle is used to compare the hybrid method to conventional LMPC and NMPC techniques.
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a hybrid model predictive control strategy for nonlinear plant wide control
IFAC Proceedings Volumes, 1999Co-Authors: Guangyan Zhu, Michael A Henson, Babatunde A OgunnaikeAbstract:Abstract A plant-wide control strategy based on integrating linear model predictive control (LMPC) and nonlinear model predictive control (NMPC) is proposed. The hybrid method is applicable to plants that can be decomposed into approximately linear Subsystems and highly nonlinear Subsystems which interact via mass and energy flows. LMPC is applied to the linear Subsystems and NMPC is applied to the nonlinear Subsystems. A controller coordination method which counteracts interaction effects is proposed for the simplest case of one linear Subsystem and one nonlinear Subsystem. A prototypical reactor separator process is used to compare the hybrid method to LMPC and NMPC.
Fatima Zohra Taousser - One of the best experts on this subject based on the ideXlab platform.
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stability analysis of a class of switched linear systems on non uniform time domains
Systems & Control Letters, 2014Co-Authors: Fatima Zohra Taousser, Michael Defoort, Mohamed DjemaiAbstract:Abstract This paper deals with the stability analysis of a class of switched linear systems on non-uniform time domains. The considered class consists of a set of linear continuous-time and linear discrete-time Subsystems. First, some conditions are derived to guarantee the exponential stability of this class of systems on time scales with bounded graininess function when the Subsystems are exponentially stable. These results are extended when considering an unstable discrete time Subsystem or an unstable continuous-time Subsystem. Some examples illustrate these results.
