2,738 research outputs found

    Rate-Privacy in Wireless Sensor Networks

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    This paper introduces the concept of rate privacy in the context of wireless sensor networks. Our discussion reveals that the concept indeed is of a great importance for the privacy preservation of such networks. As a result, we propose a buffering scheme to protect the rate from adversaries. Simulation results verify the applicability of our approach

    Quantum Dynamics in a Time-dependent Hard-Wall Spherical Trap

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    Exact solution of the Schr\"{o}dinger equation is given for a particle inside a hard sphere whose wall is moving with a constant velocity. Numerical computations are presented for both contracting and expanding spheres. The propagator is constructed and compared with the propagator of a particle in an infinite square well with one wall in uniform motion.Comment: 6 pages, 4 figures, Accepted by Europhys. Let

    Band-edge Bilayer Plasmonic Nanostructure for Surface Enhanced Raman Spectroscopy

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    Spectroscopic analysis of large biomolecules is critical in a number of applications, including medical diagnostics and label-free biosensing. Recently, it has been shown that Raman spectroscopy of proteins can be used to diagnose some diseases, including a few types of cancer. These experiments have however been performed using traditional Raman spectroscopy and the development of the Surface enhanced Raman spectroscopy (SERS) assays suitable for large biomolecules could lead to a substantial decrease in the amount of specimen necessary for these experiments. We present a new method to achieve high local field enhancement in surface enhanced Raman spectroscopy through the simultaneous adjustment of the lattice plasmons and localized surface plasmon polaritons, in a periodic bilayer nanoantenna array resulting in a high enhancement factor over the sensing area, with relatively high uniformity. The proposed plasmonic nanostructure is comprised of two interacting nanoantenna layers, providing a sharp band-edge lattice plasmon mode and a wide-band localized surface plasmon for the separate enhancement of the pump and emitted Raman signals. We demonstrate the application of the proposed nanostructure for the spectral analysis of large biomolecules by binding a protein (streptavidin) selectively on the hot-spots between the two stacked layers, using a low concentration solution (100 nM) and we successfully acquire its SERS spectrum

    DFDL: Discriminative Feature-oriented Dictionary Learning for Histopathological Image Classification

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    In histopathological image analysis, feature extraction for classification is a challenging task due to the diversity of histology features suitable for each problem as well as presence of rich geometrical structure. In this paper, we propose an automatic feature discovery framework for extracting discriminative class-specific features and present a low-complexity method for classification and disease grading in histopathology. Essentially, our Discriminative Feature-oriented Dictionary Learning (DFDL) method learns class-specific features which are suitable for representing samples from the same class while are poorly capable of representing samples from other classes. Experiments on three challenging real-world image databases: 1) histopathological images of intraductal breast lesions, 2) mammalian lung images provided by the Animal Diagnostics Lab (ADL) at Pennsylvania State University, and 3) brain tumor images from The Cancer Genome Atlas (TCGA) database, show the significance of DFDL model in a variety problems over state-of-the-art methodsComment: Accepted to IEEE International Symposium on Biomedical Imaging (ISBI), 201

    The study of nano technology utilization in upgrading the quality of construction industry with fire-engineering approach

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    Today, the first requirement for increasing quality and strength in construction industry is utilization of appropriate and high quality materials so that usage of these materials, in addition to reducing maintenance costs and also upgrading the structure's longevity, in engineering respect through change on weight reduction and increasing strength in used materials, can cause general strength of the structure against earthquakes and probable runs due to natural disasters. This requirement is very significant in passive defense scope and this task will be considered in used material in main structure of a building and also in used materials in its frontage and in terminology elaborate work. Given that one of the effects of fire on the building part and parcel of passive defense, so, this look from the perspective of fire engineering is also of particular significance. Wide studies have been performed in this ground and various factories are trying to increase their produced materials quality in today competitive world with utilization of various technologies. One of technologies considered today is Nano technology which in fact by changing the molecular structure of a material causes creating special properties in it and utilization of these properties can answer needs of producers and users for increasing quality, longevity, strength and weight reduction. In this study, it is tried to introduce materials produced by Nano technology which have special properties like resistance against fire, settlement and weight reduction and increasing resistance in tolerance of strike and injected loads to the structure in defensive point of view in civil engineering scope. Keywords: Nano technology; passive defense; building material

    fracture and microstructural study of bovine bone under mixed mode i ii loading

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    Abstract Understanding the fracture behavior and associated crack growth mechanism in bone material is an important issue for biomechanics and biomaterial researches. Fracture of bone often takes place due to complex loading conditions which result in combined tensile-shear (i.e. mixed mode) fracture mechanism. Several parameters such as loading type, applied loading direction relative to the bone axis, loading rate, age and etc., may affect the mixed mode fracture resistance and damage mechanism in such materials. In this research, a number of mixed mode I/II fracture experiments are conducted on bovine femur bone using a sub-sized test configuration called "compact beam bend (CBB)" specimen to investigate the fracture toughness of bone under different mode mixities. The specimen is rectangular beam containing a mid-edge crack that is loaded by a conventional three-point bend fixture. The results showed the dependency of bone fracture toughness on the state of mode mixity. The fracture surfaces of broken CBB specimens under different loading conditions were studied via scanning electron microscopy (SEM) observations. Fracture surface of all investigated cases (i.e. pure mode I, pure mode II and mixed mode I/II) exhibited smooth patterns demonstrating brittle fracture of bovine femur. The higher density of vascular channels and micro-cracks initiated in the weakened area surrounded by secondary osteons were found to be the main cause of the decreased bone resistance against crack growth and brittle fracture
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