1,184 research outputs found

    A unified radio control architecture for prototyping adaptive wireless protocols

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    Experimental optimization of wireless protocols and validation of novel solutions is often problematic, due to limited configuration space present in commercial wireless interfaces as well as complexity of monolithic driver implementation on SDR-based experimentation platforms. To overcome these limitations a novel software architecture is proposed, called WiSHFUL, devised to allow: i) maximal exploitation of radio functionalities available in current radio chips, and ii) clean separation between the logic for optimizing the radio protocols (i.e. radio control) and the definition of these protocols

    Unified radio and network control across heterogeneous hardware platforms

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    Experimentation is an important step in the investigation of techniques for handling spectrum scarcity or the development of new waveforms in future wireless networks. However, it is impractical and not cost effective to construct custom platforms for each future network scenario to be investigated. This problem is addressed by defining Unified Programming Interfaces that allow common access to several platforms for experimentation-based prototyping, research, and development purposes. The design of these interfaces is driven by a diverse set of scenarios that capture the functionality relevant to future network implementations while trying to keep them as generic as possible. Herein, the definition of this set of scenarios is presented as well as the architecture for supporting experimentation-based wireless research over multiple hardware platforms. The proposed architecture for experimentation incorporates both local and global unified interfaces to control any aspect of a wireless system while being completely agnostic to the actual technology incorporated. Control is feasible from the low-level features of individual radios to the entire network stack, including hierarchical control combinations. A testbed to enable the use of the above architecture is utilized that uses a backbone network in order to be able to extract measurements and observe the overall behaviour of the system under test without imposing further communication overhead to the actual experiment. Based on the aforementioned architecture, a system is proposed that is able to support the advancement of intelligent techniques for future networks through experimentation while decoupling promising algorithms and techniques from the capabilities of a specific hardware platform

    Cell Autonomous Expression of Perlecan and Plasticity of Cell Shape in Embryonic Muscle ofCaenorhabditis elegans

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    AbstractPerlecan, a component of the extracellular matrix (ECM), is essential for myofilament formation and muscle attachment inCaenorhabditis elegans.We show here that perlecan is a product of muscle and that it behaves in a cell autonomous fashion. That is, perlecan expressed in an individual muscle cell does not spread beyond the borders of the ECM underlying that cell. Using a polyclonal antibody that recognizes all isoforms of perlecan, we demonstrate that this protein first appears extracellularly at the comma stage (approx. 350 min) of development. We also show that during morphogenesis muscle cells have a heretofore undescribed plasticity of shape. This ability to regulate cell shape allows cells within a muscle quadrant to compensate for missing cells and to form a functional quadrant. A dramatic example of this morphological flexibility can be observed in animals in which the D blastomere has been removed by laser ablation. Such animals, lacking 20 of the 81 embryonic body wall muscle cells, can survive to become viable adult animals indistinguishable from wildtype animals. This demonstrates that the assembly of an embryo via a stereotypic lineage does not preclude a more general regulation during morphogenesis. It appears that embryos are flexible enough to immediately compensate for drastic alterations in tissue composition, a feature of development that may be of general importance during evolution

    Cell Autonomous Expression of Perlecan and Plasticity of Cell Shape in Embryonic Muscle ofCaenorhabditis elegans

    Get PDF
    AbstractPerlecan, a component of the extracellular matrix (ECM), is essential for myofilament formation and muscle attachment inCaenorhabditis elegans.We show here that perlecan is a product of muscle and that it behaves in a cell autonomous fashion. That is, perlecan expressed in an individual muscle cell does not spread beyond the borders of the ECM underlying that cell. Using a polyclonal antibody that recognizes all isoforms of perlecan, we demonstrate that this protein first appears extracellularly at the comma stage (approx. 350 min) of development. We also show that during morphogenesis muscle cells have a heretofore undescribed plasticity of shape. This ability to regulate cell shape allows cells within a muscle quadrant to compensate for missing cells and to form a functional quadrant. A dramatic example of this morphological flexibility can be observed in animals in which the D blastomere has been removed by laser ablation. Such animals, lacking 20 of the 81 embryonic body wall muscle cells, can survive to become viable adult animals indistinguishable from wildtype animals. This demonstrates that the assembly of an embryo via a stereotypic lineage does not preclude a more general regulation during morphogenesis. It appears that embryos are flexible enough to immediately compensate for drastic alterations in tissue composition, a feature of development that may be of general importance during evolution
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