A graph-theoretic analysis of state inference for a class of network synchronization (or diffusive) processes is pursued. Precisely, estimation is studied for a nonrandom initial condition of a canonical synchronizati...
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Split ring resonator (SRR) structures based terahertz (THz) metamaterials with different gap dimensions are fabricated on polyethylene naphthalate (PEN) films by parallel laser micro-lens array (MLA) lithography and l...
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Split ring resonator (SRR) structures based terahertz (THz) metamaterials with different gap dimensions are fabricated on polyethylene naphthalate (PEN) films by parallel laser micro-lens array (MLA) lithography and lift-off process. The narrowband resonance is achieved in single layer SRR samples. A series of single layer SRR samples are fabricated with different gap sizes to obtain successive narrowband THz resonances over a wide THz range. For broadband design, these single layer SRR samples are stacked to form a multilayer structure. The multilayer SRR is experimentally demonstrated with a much broader bandwidth of 0.221 THz and enhanced resonance up to 2.14 times as compared to the single layer SRR.
With the successful deployment of IEEE 802.11a/b/g wireless local area networks (WLANs) and the pent-up market demand for high speed wireless access, the IEEE 802.11n protocol has emerged as a promising standard with ...
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ISBN:
(纸本)9781612846842
With the successful deployment of IEEE 802.11a/b/g wireless local area networks (WLANs) and the pent-up market demand for high speed wireless access, the IEEE 802.11n protocol has emerged as a promising standard with major enhancements. In order to scale to the high physical layer transmission rate of up to 600 Mbps, the current medium access control (MAC) protocol requires significant improvements. Towards this end, several packet aggregation schemes have been proposed to reduce the inherent protocol overhead. However, choosing large frame sizes would result in increased channel access delay and jitter especially in delay-critical applications. In this paper, we propose an analytical model to obtain the optimal frame size with regard to the delay constraints of nodes. In particular, we model IEEE 802.11n aggregation scheme as a constrained convex optimization problem so as to maximize network throughput performance while considering delay constraints. Simulation results justify that our proposed model exactly satisfies average delay requirements of network nodes.
In this paper, nanopillars with heights of 1μm to 5μm and widths of 250nm to 500nm have been fabricated with a near room temperature etching process. The nanopillars were achieved with a continuous deep reactive ion...
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In this paper, nanopillars with heights of 1μm to 5μm and widths of 250nm to 500nm have been fabricated with a near room temperature etching process. The nanopillars were achieved with a continuous deep reactive ion etching technique and utilizing PMMA (polymethylmethacrylate) and Chromium as masking layers. As opposed to the conventional Bosch process, the usage of the unswitched deep reactive ion etching technique resulted in nanopillars with smooth sidewalls with a measured surface roughness of less than 40nm. Moreover, undercut was nonexistent in the nanopillars. The proposed fabrication method achieves etch rates four times faster when compared to the state-of-the-art, leading to higher throughput and more vertical side walls. The fabrication of the nanopillars was carried out keeping the CMOS process in mind to ultimately obtain a CMOS-compatible process. This work serves as an initial step in the ultimate objective of integrating photo-sensors based on these nanopillars seamlessly along with the controlling transistors to build a complete bio-inspired smart CMOS image sensor on the same wafer.
The future power grid is expected to further expand with highly distributed energy sources and smart loads. The increased size and complexity lead to increased burden on existing computational resources in energy cont...
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ISBN:
(纸本)9781467309745
The future power grid is expected to further expand with highly distributed energy sources and smart loads. The increased size and complexity lead to increased burden on existing computational resources in energy control centers. Thus the need to perform real-time assessment on such systems entails efficient means to distribute centralized functions such as state estimation in the power system. In this paper, we present our experience of prototyping a system architecture that connects distributed state estimators individually running parallel programs to solve non-linear estimation procedure. Through our experience, we highlight the needs of integrating the distributed state estimation algorithm with efficient partition and data communication tools so that distributed state estimation has low overhead compared to the centralized solution. We build a test case based on the IEEE 118 bus system and partition the state estimation of the whole system model to available HPC clusters. The measurement from the test bed demonstrates the low overhead of our solution.
Recently, the computational requirements for large scale data-intensive analysis of scientific data have grown significantly. In High Energy Physics (HEP) for example, the Large Hadron Collider (LHC) produced 13 petab...
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Recently, the computational requirements for large scale data-intensive analysis of scientific data have grown significantly. In High Energy Physics (HEP) for example, the Large Hadron Collider (LHC) produced 13 petabytes of data in 2010. This huge amount of data are processed on more than 140 computing centers distributed across 34 countries. The MapReduce paradigm has emerged as a highly successful programming model for large-scale data-intensive computing applications. However, current MapReduce implementations are developed to operate on single cluster environments and cannot be leveraged for large-scale distributed data processing across multiple clusters. On the other hand, workflow systems are used for distributed data processing across data centers. It has been reported that the workflow paradigm has some limitations for distributed data processing, such as reliability and efficiency. In this paper, we present the design and implementation of GHadoop, a MapReduce framework that aims to enable large-scale distributed computing across multiple clusters. G-Hadoop uses the Gfarm file system as an underlying file system and executes MapReduce tasks across distributed clusters. Experiments of the G-Hadoop framework on distributed clusters show encouraging results.
This paper reports the development of global FDTD models incorporated with a quasi-real anisotropic ionosphere consisting of magnetized cold plasmas. Compared to the existing global models utilizing simple conductivit...
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ISBN:
(纸本)9781467303330
This paper reports the development of global FDTD models incorporated with a quasi-real anisotropic ionosphere consisting of magnetized cold plasmas. Compared to the existing global models utilizing simple conductivity ionospheric profiles, the algorithms reported in this paper can sufficiently extend the global-scale electromagnetic simulations to much higher altitudes as the physics introduced by the spatially-varied ionospheric plasmas and the geomagnetic field can be fully included in calculations.
In a number of types of documents, ranging from forms to archive documents and books with annotations, machine printed and handwritten text may be present in the same document image, giving rise to significant issues ...
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In a number of types of documents, ranging from forms to archive documents and books with annotations, machine printed and handwritten text may be present in the same document image, giving rise to significant issues within a digitisation and recognition pipeline. It is therefore necessary to separate the two types of text before applying different recognition methodologies to each. In this paper, a new approach is proposed which strives towards identifying and separating handwritten from machine printed text using the Bag of Visual Words paradigm (BoVW). Initially, blocks of interest are detected in the document image. For each block, a descriptor is calculated based on the BoVW. The final characterization of the blocks as Handwritten, Machine Printed or Noise is made by a Support Vector Machine classifier. The promising performance of the proposed approach is shown by using a consistent evaluation methodology which couples meaningful measures along with a new dataset.
Limitation of message size of the MMS technology is one of the important factors which make this technology less attractive. This limitation restricts the system developers in developing new mobile applications using ...
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