2,579 research outputs found

    Teaching multidisciplinary engineering using concepts and technology of WSN

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    This paper discusses teaching and learning strategies of Wireless Sensor Networks technology in a new postgraduate subject run at the Faculty of Engineering and IT, University of Technology, Sydney. The aim is to present the role of using practice based and multidisciplinary methodologies in the context of new ICT technologies. This includes shared experiences, observations and common problems experienced in teaching new concepts and paradigms, standards, protocols and algorithms, embedded systems and sensor technologies. The theory of WSN is applied as a driver of system development for the group projects that students undertake in the subject. © 2012 IEEE

    Extinction Map of Baade's Window

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    Recently Wo\'zniak \& Stanek (1996) proposed a new method to investigate interstellar extinction, based on two band photometry, which uses red clump stars as a means to construct the reddening curve. I apply this method to the color-magnitude diagrams obtained by the Optical Gravitational Lensing Experiment (OGLE) to construct an extinction map of (40)2(40')^2 region of Baade's Window, with resolution of 30  arcsec\sim30\;arcsec. Such a map should be useful for studies of this frequently observed region of the Galactic bulge. The map and software useful for its applications are available via {\tt anonymous ftp}. The total extinction AVA_V varies from 1.26  mag1.26\;mag to 2.79  mag2.79\;mag within the (40)2(40')^2 field of view centered on (α2000,δ2000)=(\alpha_{2000}, \delta_{2000}) = (18:03:20.9,--30:02:06), i.e. (l,b)=(1.001,3.885)(l,b)=(1.001,-3.885). The ratio AV/E(VI)=2.49±0.02 A_V/E(V-I) = 2.49\pm0.02 is determined with this new method.Comment: revised version accepted for publication in ApJ Letters, 8 pages, uuencoded PostScript with 4 figures included; complete paper available through WWW at http://www.astro.princeton.edu/~library/prep.html; tables and auxiliary software available at ftp://www.astro.princeton.edu/stanek/Extinctio

    SU(2) × SU(2) × U(1) basis for symmetric SO(6) representations : matrix elements of the generators

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    Matrix elements of the group generators for the symmetric irreducible representations of SO(6) are explicitly calculated in a closed form employing the decomposition chain SO(6) ⊃ SU(2) x SU(2) x U(1) (which is different from the well known Wigner supermultiplet scheme). The relation to the Gel'fand Tsetlin method using SO(6) ⊃ SO(5) ⊃ ... ⊃ SO(2) is indicated. An example of a physical application is given

    Applications of cooperative WSN in homecare systems

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    Cooperation plays the crucial role in shared space of the homecare processes. It is a rather hard task to ensure effective cooperation in home care environment. This is due to variability of schedules, tasks and mobility of both patients and carers. In this paper, we discuss sensor network technology that can facilitate and improve home care cooperation scenarios. We present methodology, recommendations and applications for incorporating a WSN based solution in various areas of Homecare. We argue that even the most difficult areas of cooperation between patients and their carers such as: information retrieval, information dissemination, scheduling, coordination of short and long-term treatment can be supported by WSN based solutions. Finally, we discuss sensor network design approaches for incorporating smart communication devices and sensors to support health care workers and their patients in their daily activities. The network of smart sensors can help to maintain awareness of the activities of all stakeholders and the need to integrate communication and computer technology with the requirements of effective aged care infrastructure. © 2008 IEEE

    Are the Ogle Microlenses in the Galactic Bar?

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    The analysis of the first two years of OGLE data revealed 9 microlensing events of the galactic bulge stars, with the characteristic time scales in the range 8.6<t0<62 8.6 < t_0 < 62 days, where t0=RE/V t_0 = R_E / V . The optical depth to microlensing is larger than (3.3±1.2)×106 ( 3.3 \pm 1.2 ) \times 10^{-6}, in excess of current theoretical estimates, indicating a much higher efficiency for microlensing by either bulge or disk lenses. We argue that the lenses are likely to be ordinary stars in the galactic bar, which has its long axis elongated towards us. A relation between t0 t_0 and the lens masses remains unknown until a quantitative model of bar microlensing becomes available. At this time we have no evidence that the OGLE events are related to dark matter. The geometry of lens distribution can be determined observationally when the microlensing rate is measured over a larger range of galactic longitudes, like 10o<l<+10o -10^o < l < +10^o , and the relative proper motions of the galactic bulge (bar) stars are measured with the HST.Comment: 10 pages, 2 figures, revised version accepted for the publication in ApJL, uses AAS LaTeX aaspp.sty macro, PostScript figures and PostScript version of the paper available through anonymous ftp from astro.princeton.edu, directory stanek/tau, or on reques

    The tensor part of the Skyrme energy density functional. III. Time-odd terms at high spin

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    This article extends previous studies on the effect of tensor terms in the Skyrme energy density functional by breaking of time-reversal invariance. We have systematically probed the impact of tensor terms on properties of superdeformed rotational bands calculated within the cranked Hartree-Fock-Bogoliubov approach for different parameterizations covering a wide range of values for the isoscalar and isovector tensor coupling constants. We analyze in detail the contribution of the tensor terms to the energies and dynamical moments of inertia and study their impact on quasi-particle spectra. Special attention is devoted to the time-odd tensor terms, the effect of variations of their coupling constants and finite-size instabilities.Comment: 28 pages, 34 figure

    Modelling the Galactic Bar Using Red Clump Giants

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    The color-magnitude diagrams of 7×105\sim 7 \times 10^5 stars obtained for 12 fields across the Galactic bulge with the OGLE project reveal a well-defined population of bulge red clump giants. We find that the distributions of the apparent magnitudes of the red clump stars are systematically fainter when moving towards lower galactic ll fields. The most plausible explanation of this distinct trend is that the Galactic bulge is a bar, whose nearest end lies at positive galactic longitude. We model this Galactic bar by fitting for all fields the observed luminosity functions in the red clump region of the color-magnitude diagram. We find that almost regardless of the analytical function used to describe the 3-D stars distribution of the Galactic bar, the resulting models have the major axis inclined to the line of sight by 2030deg20-30\deg, with axis ratios corresponding to x0:y0:z0=3.5:1.5:1x_0:y_0:z_0=3.5:1.5:1. This puts a strong constraint on the possible range of the Galactic bar models. Gravitational microlensing can provide us with additional constrains on the structure of the Galactic bar.Comment: submitted to the New Astronomy, 27 pages, 11 figures; also available at ftp://www.astro.princeton.edu/stanek/Barmodel and through WWW at http://www.astro.princeton.edu/~library/prep.htm

    Color-Magnitude Diagram Distribution of the Bulge Red Clump Stars - Evidence for the Galactic Bar

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    The color-magnitude diagrams of 5×105\sim 5\times 10^5 stars obtained for 13 fields towards the Galactic bulge with the OGLE project reveal a well-defined population of bulge red clump stars. We find that the distributions of the extinction-adjusted apparent magnitudes of the red clump stars in fields lying at l=±5degl=\pm5\deg in galactic longitude differ by 0.37±0.025  mag0.37\pm0.025\;mag. Assuming that the intrinsic luminosity distribution of the red clump stars is the same on both sides of the Galactic center, this implies that the distances to the red clump stars in the two fields differ by a factor of 1.185±0.0151.185\pm0.015. A plausible explanation of the observed difference in the luminosity distribution is that the Galactic bulge is a triaxial structure, or bar, which is inclined to the line of sight by no more than 45deg45\deg, with the part of the bar at the positive galactic longitude being closer to us. This agrees rather well with other studies indicating the presence of the bar in the center of the Galaxy. Color-magnitude diagram data are accessible over the computer network with anonymous {\tt ftp}.Comment: 10 pages, 6 figures, uses AAS LaTeX aaspp.sty macro, PostScript figures available through the anonymous ftp or on request, accepted for the publication in the ApJ
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