The Experts below are selected from a list of 63408 Experts worldwide ranked by ideXlab platform
Matthieu Horgnies - One of the best experts on this subject based on the ideXlab platform.
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polymeric microstructures induced by freeze drying process comparative study of ps41 paa 271 morphologies after impregnations in water and in an alkaline solution
Journal of Materials Processing Technology, 2009Co-Authors: Matthieu HorgniesAbstract:Surface of polymeric coating can be modified after being submitted to treatment based oil freeze-drying. Morphology of polystyrene-b-poly(acrylic acid) (PS41 -PAA(271)) diblock copolymers was investigated by using scanning electron microscopy (SEM). After clip-coating oil stainless steel substrate, influences of the nature and the pH of the immersing liquid, used before freeze-drying, were established. If water has impregnated the polymer in order to form a hydrogel, the surface could acquire a cellular monolayer structure after freeze-drying while stretched polymeric nodules, affected by the conditions of sublimation, cover some other parts of the surface. The porous monolayer happens when freeze-drying occurs in a homogenous and well-crystallised icy material. Observations of nucleation sites linked by polymeric filaments could be considered as the first step of growth of this Regular Network. In the other hand, if a KOH alkaline Solution has impregnated the polymer before freeze-drying, ionic species affect the morphology by inducing specific lamellar structures that close the porous Structure. XPS analyses highlight that the carboxylic functions of PS-PAA coating could be deprotonated during the immersion in the alkaline solution. This deprotonation induces polyacrylate-based compounds that Could disturb the growth of the cellular polymeric Network. This phenomenon Should be avoided by using a neutral immersing solution in order to obtain a homogenous and Porous monolayer of PS-PAA after freeze-drying. (C) 2009 Elsevier B.V. All rights reserved.
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polymeric microstructures induced by freeze drying process comparative study of ps41 paa 271 morphologies after impregnations in water and in an alkaline solution
Journal of Materials Processing Technology, 2009Co-Authors: Matthieu HorgniesAbstract:Surface of polymeric coating can be modified after being submitted to treatment based oil freeze-drying. Morphology of polystyrene-b-poly(acrylic acid) (PS41 -PAA(271)) diblock copolymers was investigated by using scanning electron microscopy (SEM). After clip-coating oil stainless steel substrate, influences of the nature and the pH of the immersing liquid, used before freeze-drying, were established. If water has impregnated the polymer in order to form a hydrogel, the surface could acquire a cellular monolayer structure after freeze-drying while stretched polymeric nodules, affected by the conditions of sublimation, cover some other parts of the surface. The porous monolayer happens when freeze-drying occurs in a homogenous and well-crystallised icy material. Observations of nucleation sites linked by polymeric filaments could be considered as the first step of growth of this Regular Network. In the other hand, if a KOH alkaline Solution has impregnated the polymer before freeze-drying, ionic species affect the morphology by inducing specific lamellar structures that close the porous Structure. XPS analyses highlight that the carboxylic functions of PS-PAA coating could be deprotonated during the immersion in the alkaline solution. This deprotonation induces polyacrylate-based compounds that Could disturb the growth of the cellular polymeric Network. This phenomenon Should be avoided by using a neutral immersing solution in order to obtain a homogenous and Porous monolayer of PS-PAA after freeze-drying. (C) 2009 Elsevier B.V. All rights reserved.
Radu Marculescu - One of the best experts on this subject based on the ideXlab platform.
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Energy- And performance-aware mapping for Regular NoC architectures
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2005Co-Authors: Jingcao Hu, Radu MarculescuAbstract:In this paper, we present an algorithm which automatically maps a given set of intellectual property onto a generic Regular Network-on-chip (NoC) architecture and constructs a deadlock-free deterministic routing function such that the total communication energy is minimized. At the same time, the performance of the resulting communication system is guaranteed to satisfy the specified design constraints through bandwidth reservation. As the main theoretical contribution, we first formulate the problem of energy- and performance-aware mapping in a topological sense, and show how the routing flexibility can be exploited to expand the solution space and improve the solution quality. An efficient branch-and-bound algorithm is then proposed to solve this problem. Experimental results show that the proposed algorithm is very fast, and significant communication energy savings can be achieved. For instance, for a complex video/audio application, 51.7% communication energy savings have been observed, on average, compared to an ad hoc implementation.
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exploiting the routing flexibility for energy performance aware mapping of Regular noc architectures
Design Automation and Test in Europe, 2003Co-Authors: Jingcao Hu, Radu MarculescuAbstract:In this paper, we present an algorithm which automatically maps the IPs onto a generic Regular Network on Chip (NoC) architecture and constructs a deadlock-free deterministic routing function such that the total communication energy is minimized. At the same time, the performance of the resulting communication system is guaranteed to satisfy the specified constraints through bandwidth reservation. As the main contribution, we first formulate the problem of energy/performance aware mapping, in a topological sense, and show how the routing flexibility can be exploited to expand the solution space and improve the solution quality. An efficient branch-and-bound algorithm is then described to solve this problem. Experimental results show that the proposed algorithm is very fast, and significant energy savings can be achieved. For instance, for a complex video/audio application, 51.7% energy savings have been observed, on average, compared to an ad-hoc implementation.
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energy aware mapping for tile based noc architectures under performance constraints
Asia and South Pacific Design Automation Conference, 2003Co-Authors: Jingcao Hu, Radu MarculescuAbstract:In this paper, we present an algorithm which automatically maps the IPs/cores onto a generic Regular Network on Chip (NoC) architecture such that the total communication energy is minimized. At the same time, the performance of the mapped system is guaranteed to satisfy the specified constraints through bandwidth reservation. As the main contribution, we first formulate the problem of energy-aware mapping, in a topological sense, and then propose an efficient branch-and-bound algorithm to solve it. Experimental results show that the proposed algorithm is very fast and robust, and significant energy savings can be achieved. For instance, for a complex video/audio SoC design, on average, 60.4% energy savings have been observed compared to an ad-hoc implementation.
Chunni Wang - One of the best experts on this subject based on the ideXlab platform.
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autapse induced target wave spiral wave in Regular Network of neurons
Science China-physics Mechanics & Astronomy, 2014Co-Authors: Huixin Qin, Chunni Wang, Runtong ChuAbstract:Autapse is a type of synapse that connects axon and dendrites of the same neuron, and the effect is often detected by close-loop feedback in axonal action potentials to the owned dendritic tree. An artificial autapse was introduced into the Hindmarsh-Rose neuron model, and a Regular Network was designed to detect the Regular pattern formation induced by autapse. It was found that target wave emerged in the Network even when only a single autapse was considered. By increasing the (autapse density) number of neurons with autapse, for example, a Regular area (2×2, 3×3, 4×4, 5×5 neurons) under autapse induced target wave by selecting the feedback gain and time-delay in autapse. Spiral waves were also observed under optimized feedback gain and time delay in autapses because of coherence-like resonance in the Network induced by some electric autapses connected to some neurons. This confirmed that the electric autapse has a critical role in exciting and regulating the collective behaviors of neurons by generating stable Regular waves (target waves, spiral waves) in the Network. The wave length of the induced travelling wave (target wave, spiral wave), because of local effect of autapse, was also calculated to understand the waveprofile in the Network of neurons.
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autapse induced spiral wave in Network of neurons under noise
PLOS ONE, 2014Co-Authors: Huixin Qin, Chunni WangAbstract:Autapse plays an important role in regulating the electric activity of neuron by feedbacking time-delayed current on the membrane of neuron. Autapses are considered in a local area of Regular Network of neurons to investigate the development of spatiotemporal pattern, and emergence of spiral wave is observed while it fails to grow up and occupy the Network completely. It is found that spiral wave can be induced to occupy more area in the Network under optimized noise on the Network with periodical or no-flux boundary condition being used. The developed spiral wave with self-sustained property can regulate the collective behaviors of neurons as a pacemaker. To detect the collective behaviors, a statistical factor of synchronization is calculated to investigate the emergence of ordered state in the Network. The Network keeps ordered state when self-sustained spiral wave is formed under noise and autapse in local area of Network, and it independent of the selection of periodical or no-flux boundary condition. The developed stable spiral wave could be helpful for memory due to the distinct self-sustained property.
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Simulating the formation of spiral wave in the neuronal system
Nonlinear Dynamics, 2013Co-Authors: Chunni Wang, Wuyin JinAbstract:Some experimental results have confirmed that a spiral wave could be observed in the cortex of brain. The biological Hodgkin–Huxley neurons are used to construct a Regular Network with nearest-neighbor connection, artificial line defects are generated to block the traveling wave in the Network, and the potential mechanism for formation of spiral wave is investigated. A target wave is generated in a local area by imposing two external forcing currents with diversity (I 0−I 1) in different areas of the Network. It is confirmed that spiral wave could be induced by the defects even if no specific initial values are used. A single perfect spiral wave can occupy the Network when the coupling intensity exceeds certain threshold; otherwise, a group of spiral waves emerges in the Network. Certain channel noise can enhance the diversity (I 0−I 1) for generating target wave, and then spiral waves are induced by blocking the target wave with defects under no-flux and/or periodic boundary conditions in the Network.
Jingcao Hu - One of the best experts on this subject based on the ideXlab platform.
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Energy- And performance-aware mapping for Regular NoC architectures
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2005Co-Authors: Jingcao Hu, Radu MarculescuAbstract:In this paper, we present an algorithm which automatically maps a given set of intellectual property onto a generic Regular Network-on-chip (NoC) architecture and constructs a deadlock-free deterministic routing function such that the total communication energy is minimized. At the same time, the performance of the resulting communication system is guaranteed to satisfy the specified design constraints through bandwidth reservation. As the main theoretical contribution, we first formulate the problem of energy- and performance-aware mapping in a topological sense, and show how the routing flexibility can be exploited to expand the solution space and improve the solution quality. An efficient branch-and-bound algorithm is then proposed to solve this problem. Experimental results show that the proposed algorithm is very fast, and significant communication energy savings can be achieved. For instance, for a complex video/audio application, 51.7% communication energy savings have been observed, on average, compared to an ad hoc implementation.
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exploiting the routing flexibility for energy performance aware mapping of Regular noc architectures
Design Automation and Test in Europe, 2003Co-Authors: Jingcao Hu, Radu MarculescuAbstract:In this paper, we present an algorithm which automatically maps the IPs onto a generic Regular Network on Chip (NoC) architecture and constructs a deadlock-free deterministic routing function such that the total communication energy is minimized. At the same time, the performance of the resulting communication system is guaranteed to satisfy the specified constraints through bandwidth reservation. As the main contribution, we first formulate the problem of energy/performance aware mapping, in a topological sense, and show how the routing flexibility can be exploited to expand the solution space and improve the solution quality. An efficient branch-and-bound algorithm is then described to solve this problem. Experimental results show that the proposed algorithm is very fast, and significant energy savings can be achieved. For instance, for a complex video/audio application, 51.7% energy savings have been observed, on average, compared to an ad-hoc implementation.
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energy aware mapping for tile based noc architectures under performance constraints
Asia and South Pacific Design Automation Conference, 2003Co-Authors: Jingcao Hu, Radu MarculescuAbstract:In this paper, we present an algorithm which automatically maps the IPs/cores onto a generic Regular Network on Chip (NoC) architecture such that the total communication energy is minimized. At the same time, the performance of the mapped system is guaranteed to satisfy the specified constraints through bandwidth reservation. As the main contribution, we first formulate the problem of energy-aware mapping, in a topological sense, and then propose an efficient branch-and-bound algorithm to solve it. Experimental results show that the proposed algorithm is very fast and robust, and significant energy savings can be achieved. For instance, for a complex video/audio SoC design, on average, 60.4% energy savings have been observed compared to an ad-hoc implementation.
Federica Lo Verso - One of the best experts on this subject based on the ideXlab platform.
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computational investigation of microgels synthesis and effect of the microstructure on the deswelling behavior
Soft Matter, 2018Co-Authors: Angel J Moreno, Federica Lo VersoAbstract:We present computer simulations of a realistic model of microgels. Unlike the Regular Network frameworks usually assumed in the simulation literature, we model and simulate a realistic and efficient synthesis route, mimicking cross-linking of functionalized chains inside a cavity. This model is inspired, e.g., by microfluidic fabrication of microgels from macromolecular precursors and is different from standard polymerization routes. The assembly of the chains is mediated by a low fraction of interchain crosslinks. The microgels are polydisperse in size and shape but globally spherical objects. In order to deeply understand the microgel structure and eventually improve the synthesis protocol we characterize their conformational properties and deswelling kinetics, and compare them with the results found for microgels obtained via underlying Regular (diamond-like) structures. For the same molecular weight, monomer concentration and effective degree of cross-linking, the specific microstructure of the microgel has no significant effect on the locus of the volume phase transition (VPT). However, it strongly affects the deswelling kinetics, as revealed by a consistent analysis of the domain growth during the microgel collapse. Though both the disordered and the Regular Networks exhibit a similar early growth of the domains, an acceleration is observed in the Regular Network at the late stage of the collapse. Similar trends are found for the dynamic correlations coupled to the domain growth. As a consequence, the fast late processes for the domain growth and the dynamic correlations in the Regular Network are compensated, and the dynamic correlations follow a power-law dependence on the growing length scale that is independent of the microgel microstructure.
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computational investigation of microgels synthesis and effect of the microstructure on the deswelling behavior
arXiv: Soft Condensed Matter, 2018Co-Authors: Angel J Moreno, Federica Lo VersoAbstract:We present computer simulations of a realistic model of microgels. Unlike the Regular Network frameworks usually assumed in the simulation literature, we model and simulate a realistic and efficient synthesis route, mimicking cross-linking of functionalized chains inside a cavity. This model is inspired, e.g., by microfluidic fabrication of microgels from macromolecular precursors and is different from standard polymerization routes. The assembly of the chains is mediated by a low fraction of interchain crosslinks. The microgels are polydisperse in size and shape but globally spherical objects. In order to deeply understand the microgel structure and eventually improve the synthesis protocol we characterize their conformational properties and deswelling kinetics, and compare them with the results found for microgels obtained via underlying Regular (diamond-like) structures. The specific microstructure of the microgel has no significant effect on the locus of the volume phase transition (VPT). However, it strongly affects the deswelling kinetics, as revealed by a consistent analysis of the domain growth during the microgel collapse. Though both the disordered and the Regular Networks exhibit a similar early growth of the domains, an acceleration is observed in the Regular Network at the late stage of the collapse. Similar trends are found for the dynamic correlations coupled to the domain growth. As a consequence, the fast late processes for the domain growth and the dynamic correlations in the Regular Network are compensated, and the dynamic correlations follow a power-law dependence on the growing length scale that is independent of the microgel microstructure.
