With the emergence of the Internet of Things (IoT) vision, RFID technology has attracted more and more interests from many industries. In the EPCglobal standard which standardizes RFID architectural framework and inte...
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Virtual infrastructures (VIs) consolidated the dynamic provisioning of computing and communication resources. A VI is a set of virtual machines interconnected by virtual links and switches/routers. Infrastructure prov...
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Virtual infrastructures (VIs) consolidated the dynamic provisioning of computing and communication resources. A VI is a set of virtual machines interconnected by virtual links and switches/routers. Infrastructure providers (InPs) manage the physical substrates in which virtual resources requested by VIs (such as CPU, disk, memory, bandwidth) are reserved and allocated. Resource allocation is a complex problem that needs to satisfy different goals: users expect to run their applications on survivable VIs, while InPs aim to maximize profits, minimize costs and reduce substrate fragmentation. However, there is a dichotomy between minimizing substrate fragmentation, by co-locating VIs, and maximizing VI survivability, by sparsely allocating resources in order to decrease the impact of substrate failures. In this context, this paper discusses VI survivability and its impact on substrate fragmentation. We propose a mixed integer linear programming model to allocate resources considering the joint coordination of fragmentation and survivability. Experimental results suggest that it is possible to enhance VI survivability without significantly impacting substrate fragmentation.
Spindle-shaped nematic droplets (tactoids) form in solutions of rod-like molecules at the onset of the liquid crystalline phase. Their unique shape and internal structure result from the interplay of the elastic defor...
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Spindle-shaped nematic droplets (tactoids) form in solutions of rod-like molecules at the onset of the liquid crystalline phase. Their unique shape and internal structure result from the interplay of the elastic deformation of the nematic and anisotropic surface forces. The balance of these forces dictates that tactoids must display a continuous variation in aspect ratio and director-field configuration. Yet, such continuous transition has eluded observation for decades: tactoids have displayed either a bipolar configuration with particles aligned parallel to the droplet interface or a homogeneous configuration with particles aligned parallel to the long axis of the tactoid. Here, we report the first observation of the continuous transition in shape and director-field configuration of tactoids in true solutions of carbon nanotubes in chlorosulfonic acid. This observation is possible because the exceptional length of carbon nanotubes shifts the transition to a size range that can be visualized by optical microscopy. Polarization micrographs yield the interfacial and elastic properties of the system. Absorbance anisotropy measurements provide the highest nematic order parameter (S=0.79) measured to date for a nematic phase of carbon nanotubes at coexistence with its isotropic phase.
We present multi-junction small molecule organic photovoltaic (OPV) cells with efficiencies over 11%. The devices consist of two or three, vacuum thermally evaporated planar-mixed heterojunction sub-cells with minimal...
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We present multi-junction small molecule organic photovoltaic (OPV) cells with efficiencies over 11%. The devices consist of two or three, vacuum thermally evaporated planar-mixed heterojunction sub-cells with minimal absorption overlap between the cells. By introducing a transparent interconnecting layer, a dual element (tandem) cell achieves a power conversion efficiency of 10.0 ± 0.5%. We further improve the cell performance by adding an additional (3 rd ) sub-cell that absorbs at the second order optical interference maximum within the stack. The triple-junction cell significantly improves the quantum efficiency at shorter wavelengths, achieving a power conversion efficiency of 11.1 ± 0.5%, which to our knowledge, is the highest reported for a multi-junction OPV cell in the scientific literature.
In this paper we present the use of participatory design in a public health management system, called PRONTO, that is being developed in Brazil. This system involves a partnership between the city hall and the Univers...
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In this paper we present the use of participatory design in a public health management system, called PRONTO, that is being developed in Brazil. This system involves a partnership between the city hall and the University of Blumenau and it is being developed by the Development Laboratory and Transfer of Technology. The project involves a health network with 64 units of family health, 8 ambulatories and 1 polyclinic. The paper describes the experience in the project phase of the Multidisciplinary Treatment System module and presents the obtained results.
Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to no...
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Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x, vx, vy) is presented [1]. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volume algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented. [ABSTRACT FROM AUTHOR]
We demonstrate real time terahertz detection based on its absorption by carbon nanotubes composite and detection of the generated photoacoustic signal. This method has advantages of real time response, compact size an...
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With the emergence of the Internet of Things (IoT) vision, RFID technology has attracted more and more interests from many industries. In the EPCglobal standard which standardizes RFID architectural framework and inte...
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With the emergence of the Internet of Things (IoT) vision, RFID technology has attracted more and more interests from many industries. In the EPCglobal standard which standardizes RFID architectural framework and interfaces, the Electronic Product Code Information System (EPCIS) - the repository in the RFID network - plays a pivotal role in storing dynamic and historical RFID trajectory data, well-tailored to supply chain applications. However, in the IoT era, EPCIS should be capable of storing a large amount of realtime and continuous time-series RFID data in a scalable manner. Therefore, in this paper, we analyze the requirements and current design of EPCIS and report current limitations of SQL-based approaches for IoT applications. To cope with these limitations, we explore a NoSQL-based approach for EPCIS in the IoT and propose a column-family-based data model and customization for Cassandra-based EPCIS. Using real-world implementation, we also conduct a performance comparison between MySQL and Cassandra in different deployment scenarios (i.e., physical and virtual machines). As a result, we show the benefits of using Cassandra datastore for EPCIS in the IoT in terms of response time, throughput, and flexibility.
A narrow-band transmission filter is demonstrated near normal incidence that operates through relaxation of supported-mode selection rules and is explained in the context of group theory. We calculated the transverse ...
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A narrow-band transmission filter is demonstrated near normal incidence that operates through relaxation of supported-mode selection rules and is explained in the context of group theory. We calculated the transverse magnetic and transverse electric dispersion relations of a dielectric grating in the subwavelength and near-wavelength region using finite element modal analysis and determine the modes' corresponding irreducible representations. Coupling to select transverse magnetic modes at normal incidence is optimized to yield broadband high reflectance that acts as the background for the transmission filter. While some modes couple at normal incidence, others are shown to remain inaccessible due to symmetry mismatch. Away from normal incidence, the reduced symmetry relaxes the selection rules, enabling weak coupling between the incident field and these symmetry-protected modes. This weak coupling produces narrow transmission bands within the opaque background. Furthermore, by choosing the plane of incidence to include or exclude the grating periodicity, we show that orthogonal mode sets can independently be selected to couple to the incident light, yielding separate transmission bands. This spectral filtering is experimentally demonstrated with a suspended silicon grating in the infrared spectrum (7–14μm), which agrees well with simulated transmittance spectra and modal analysis.
In this paper, we demonstrate the stable operation of integrated 4H-silicon carbide (SiC) diode bridge rectifier circuits at high temperature up to 773 K for the first time. The turn-on voltages of the fabricated 4H-S...
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In this paper, we demonstrate the stable operation of integrated 4H-silicon carbide (SiC) diode bridge rectifier circuits at high temperature up to 773 K for the first time. The turn-on voltages of the fabricated 4H-SiC pn diode are 2.6 V and 1.4 V at room temperature and 773 K, respectively, with a low shifting rate of 2.2 mV/K. The integration of the 4H-SiC diode bridge rectifier circuit was achieved with contact and interconnect metallization technique for high temperature. The demonstration of the extremely high temperature operation of the integrated 4H-SiC diode bridge rectifier circuits brings promising applications in harsh environment electronics and sensing.
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