77 research outputs found

    A Safety Support System for Children\u27s Antiloss

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    In the recent past, crimes against children and the number of the missing children have been stayed at high. It is a tragic disaster for a family if their child is missing. Feeling safe about their children is very important for the parents. Therefore, there is an urgent requirement for safety support systems to prevent crimes against children and for anti-loss, particularly when the children are on their own, such as on the ways to and from schools. Thanks to the highly development of telecommunication and mobile technologies, preventive devices such as child ID kits, family trackers have come to light. However, they haven\u27t been impressive solutions yet as they only track current positions of the children and lack of intimations for the parents when their children are under potential dangers. In this thesis, a data mining framework is introduced, in which secure areas and secure paths of the children are learned based on their location histories. When the system predicts the children to be potentially unsafe (e.g., in a strange area or on a strange route), automatic reports will be sent to their parents. Furthermore, an indoor positioning method utilizing Bluetooth is also proposed. Based on the android platform, a prototype of the application for both children and parents is developed incorporating with the proposed techniques in this thesis

    Coherent manipulation of electron spins up to ambient temperatures in Cr5+^{5+}(S=1/2) doped K3_3NbO8_8

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    We report coherent spin manipulation on Cr5+^{5+} (\emph{S} = 1/2, \emph{I} = 0) doped K3_3NbO8_8, which constitutes a dilute two-level model relevant for use as a spin qubit. Rabi oscillations are observed for the first time in a spin system based on transition metal oxides up to room temperature. At liquid helium temperature the phase coherence relaxation time \emph{T2T_2} reaches 10\sim 10 μ\mus and, with a Rabi frequency of 20 MHz, yields a single qubit figure of merit \emph{QMQ_M} of about 500. This shows that a diluted ensemble of Cr5+^{5+} (\emph{S} = 1/2) doped K3_3NbO8_8 is a potential candidate for solid-state quantum information processing.Comment: 4 page

    A Fast Supportive and Trustworthy Cloud Services

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    Trust management is a standout amongst the most difficult issues for the selection and development of cloudcomputing. The profoundly unique, circulated, and non-straightforward nature of cloud management presents several challenging issues, for example, protection, security, and availability. Although a few arrangements have been proposed as of late in overseeing trust feedbacks in cloud situations, how to decide the validity of trust inputs is for the most part disregarded. In this project the framework proposed a notoriety based trust administration structure that gives an arrangement of functionalities to convey Trust as a Service (TaaS). "Trust as aService" (TaaS) structure to enhance routes on put stock in management in cloud situations. The approaches have been approved by the model framework and investigational comes about.

    Multi-frequency Ferromagnetic Resonance Investigation of Nickel Nanocubes Encapsulated in Diamagnetic Magnesium Oxide Matrix

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    Partially aligned nickel nanocubes were grown epitaxially in a diamagnetic magnesium oxide (MgO:Ni) host and studied by a continuous wave ferromagnetic resonance (FMR) spectroscopy at the X-band (9.5 GHz) from ca. 117 to 458 K and then at room temperature for multiple external magnetic fields/resonant frequencies from 9.5 to 330 GHz. In contrast to conventional magnetic susceptibility studies that provided data on the bulk magnetization, the FMR spectra revealed the presence of three different types of magnetic Ni nanocubes in the sample. Specifically, three different ferromagnetic resonances were observed in the X-band spectra: a line 1 assigned to large nickel nanocubes, a line 2 corresponding to the nanocubes exhibiting saturated magnetization even at ca. 0.3 T field, and a high field line 3 (geff ∼ 6.2) tentatively assigned to small nickel nanocubes likely having their hard magnetization axis aligned along or close to the direction of the external magnetic field. Based on the analysis of FMR data, the latter nanocubes possess an anisotropic internal magnetic field of at least ∼1.0 T in magnitude

    Dzyaloshinsky-Moriya Anisotropy in the Spin-1/2 Kagom\'e Compound ZnCu3_{3}(OH)6_{6}Cl2_{2}

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    We report the determination of the Dzyaloshinsky-Moriya interaction, the dominant magnetic anisotropy term in the \kagome spin-1/2 compound {\herbert}. Based on the analysis of the high-temperature electron spin resonance (ESR) spectra, we find its main component Dz=15(1)|D_z|=15(1) K to be perpendicular to the \kagome planes. Through the temperature dependent ESR line-width we observe a building up of nearest-neighbor spin-spin correlations below \sim150 K.Comment: 4 pages, 3 figures, minor modification

    Spin polarized transport driven by square voltage pulses in a quantum dot system

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    We calculate current, spin current and tunnel magnetoresistance (TMR) for a quantum dot coupled to ferromagnetic leads in the presence of a square wave of bias voltage. Our results are obtained via time-dependent nonequilibrium Green function. Both parallel and antiparallel lead magnetization alignments are considered. The main findings include a wave of spin accumulation and spin current that can change sign as the time evolves, spikes in the TMR signal and a TMR sign change due to an ultrafast switch from forward to reverse current in the emitter lead.Comment: 11 pages, 5 figure

    Quantum computing with defects

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    Identifying and designing physical systems for use as qubits, the basic units of quantum information, are critical steps in the development of a quantum computer. Among the possibilities in the solid state, a defect in diamond known as the nitrogen-vacancy (NV-1) center stands out for its robustness - its quantum state can be initialized, manipulated, and measured with high fidelity at room temperature. Here we describe how to systematically identify other deep center defects with similar quantum-mechanical properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate defect systems. To illustrate these points in detail, we compare electronic structure calculations of the NV-1 center in diamond with those of several deep centers in 4H silicon carbide (SiC). We then discuss the proposed criteria for similar defects in other tetrahedrally-coordinated semiconductors.Comment: 31 pages, 7 figures, 2 table

    Decay of Rabi oscillations induced by magnetic dipole interactions in diluted paramagnetic solids

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    Decay of Rabi oscillations of equivalent spins diluted in diamagnetic solid matrix and coupled by magnetic dipole interactions is studied. It is shown that these interactions result in random shifts of spin transient nutation frequencies and thus lead to the decay of the transient signal. Averaging over random spatial distribution of spins within the solid and over their spectral positions within magnetic resonance line, we obtain analytical expressions for the decay of Rabi oscillations. The rate of the decay in the case when the half-width of magnetic resonance line exceeds Rabi frequency is found to depend on the intensity of resonant microwave field and on the spin concentration. The results are compared with the literature data for E1' centers in glassy silica and [AlO4] centers in quartz.Comment: 14 pages, 3 figure

    3D Visualization Development of SIUE Campus

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    Geographic Information Systems (GIS) has progressed from the traditional map-making to the modern technology where the information can be created, edited, managed and analyzed. Like any other models, maps are simplified representations of real world. Hence visualization plays an essential role in the applications of GIS. The use of sophisticated visualization tools and methods, especially three dimensional (3D) modeling, has been rising considerably due to the advancement of technology. There are currently many off-the-shelf technologies available in the market to build 3D GIS models. One of the objectives of this research was to examine the available ArcGIS and its extensions for 3D modeling and visualization and use them to depict a real world scenario. Furthermore, with the advent of the web, a platform for accessing and sharing spatial information on the Internet, it is possible to generate interactive online maps. Integrating Internet capacity with GIS functionality redefines the process of sharing and processing the spatial information. Enabling a 3D map online requires off-the-shelf GIS software, 3D model builders, web server, web applications and client server technologies. Such environments are either complicated or expensive because of the amount of hardware and software involved. Therefore, the second objective of this research was to investigate and develop simpler yet cost-effective 3D modeling approach that uses available ArcGIS suite products and the free 3D computer graphics software for designing 3D world scenes. Both ArcGIS Explorer and ArcGIS Online will be used to demonstrate the way of sharing and distributing 3D geographic information on the Internet. A case study of the development of 3D campus for the Southern Illinois University Edwardsville is demonstrated
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