Service and device discovery of nodes in a wireless sensor network

Emerging wireless communication standards and more capable sensors and actuators have pushed further development of wireless sensor networks. Deploying a large number of sensor\ud nodes requires a high-level framework enabling the devices to present themselves and the resources they hold. The device and the resources can be described as services, and in this paper, we review a number of well-known service discovery protocols. Bonjour stands out with its auto-configuration, distributed architecture, and sharing of resources. We also present a lightweight implementation in order to demonstrate that an emerging standards-based device and service discovery protocol can actually be deployed on small wireless sensor nodes

Partitioning technique for a discrete quantum system

We develop the partitioning technique for quantum discrete systems. The graph consists of several subgraphs: a central graph and several branch graphs, with each branch graph being rooted by an individual node on the central one. We show that the effective Hamiltonian on the central graph can be constructed by adding additional potentials on the branch-root nodes, which generates the same result as does the the original Hamiltonian on the entire graph. Exactly solvable models are presented to demonstrate the main points of this paper.Comment: 7 pages, 2 figure

Counting Guns in Early America

Probate inventories, though perhaps the best prevailing source for determining ownership patterns in early America, are incomplete and fallible. In this Article, the authors suggest that inferences about who owned guns can be improved by using multivariate techniques and control variables of other common objects. To determine gun ownership from probate inventories, the authors examine three databases in detail-Alice Hanson Jones\u27s national sample of 919 inventories (1774), 149 inventories from Providence, Rhode Island (1679-1726), and Gunston Hall Plantation\u27s sample of 325 inventories from Maryland and Virginia (1740-1810). Also discussed are a sample of 59 probate inventories from Essex County, Massachusetts (1636-1650), Gloria L. Main\u27s study of 604 Maryland estates (1657-1719), Anna Hawley\u27s study of 221 Surry County, Virginia estates (1690-1715), a sample of 289 male inventories from Vermont (1773-1790), and Judith A. McGaw\u27s study of 250 estates in New Jersey and Pennsylvania (1714-1789). Guns are found in 50- 73% of the male estates in each of the eight databases and in 6-38% of the female estates in each of the first four databases. Gun ownership is particularly high compared to other common items. For example, in 813 itemized male inventories from the 1774 Jones national database, guns are listed in 54% of estates, compared to only 30% of estates listing any cash, 14% listing swords or edged weapons, 25% listing Bibles, 62% listing any book, and 79% listing any clothes. Using hierarchical loglinear modeling, the authors show that guns are more common in early American inventories where the decedent was male, Southern, rural, slave-owning, or above the lowest social class-or where the inventories were more detailed. The picture of gun ownership that emerges from these analyses substantially contradicts the assertions of Michael Bellesiles in Arming America: The Origins of a National Gun Culture (Arming America). Contrary to Arming America\u27s claims about probate inventories in seventeenth and eighteenth-century America, there were high numbers of guns, guns were much more common than swords or other edged weapons, women in 1774 owned guns at rates (18%) higher than Bellesiles claimed men did in 1765-1790 (14.7%), and 87-91% of gun-owning estates listed at least one gun that was not old or broken. The authors replicated portions of Bellesiles\u27s published study in which he both counted guns in probate inventories and cited sources containing inventories. They conclude that Bellesiles appears to have substantially misrecorded the seventeenth and eighteenth century probate data he presents. For the Providence probate data (1679-1726), Bellesiles has misclassified over 60% of the inventories he examined. He repeatedly counted women as men, counted about a hundred wills that never existed, and claimed that the inventories evaluated more than half of the guns as old or broken when fewer than 10% were so listed. Nationally, for the 1765-1790 period, the average percentage of estates listing guns that Bellesiles reports (14.7%) is not mathematically possible, given the regional averages he reports and known minimum sample sizes. Last, an archive of probate inventories from San Francisco in which Bellesiles claims to have counted guns apparently does not exist. By all accounts, the entire archive before 1860 was destroyed in the San Francisco earthquake and subsequent fire of 1906. Neither part of his study of seventeenth and eighteenth-century probate data is replicable, nor is his study of probate data from the 1840s and 1850s

Post-Wick theorems for symbolic manipulation of second-quantized expressions in atomic many-body perturbation theory

Manipulating expressions in many-body perturbation theory becomes unwieldily with increasing order of the perturbation theory. Here I derive a set of theorems for efficient simplification of such expressions. The derived rules are specifically designed for implementing with symbolic algebra tools. As an illustration, we count the numbers of Brueckner-Goldstone diagrams in the first several orders of many-body perturbation theory for matrix elements between two states of a mono-valent system.Comment: J. Phys. B. (in press); Mathematica packages available from http://wolfweb.unr.edu/homepage/andrei/WWW-tap/mathematica.htm

Studies of thermionic materials for space power applications informal monthly report, sep. 1 - sep. 30, 1963

Thermionic materials for space power application - uranium carbide-zirconium carbide fuels and tungsten claddin

Tangential Touch between the Free and the Fixed Boundary in a Semilinear Free Boundary Problem in Two Dimensions

The main result of this paper concerns the behavior of a free boundary arising from a minimization problem, close to the fixed boundary in two dimensions

Many-body-QED perturbation theory: Connection to the Bethe-Salpeter equation

The connection between many-body theory (MBPT)--in perturbative and non-perturbative form--and quantum-electrodynamics (QED) is reviewed for systems of two fermions in an external field. The treatment is mainly based upon the recently developed covariant-evolution-operator method for QED calculations [Lindgren et al. Phys. Rep. 389, 161 (2004)], which has a structure quite akin to that of many-body perturbation theory. At the same time this procedure is closely connected to the S-matrix and the Green's-function formalisms and can therefore serve as a bridge between various approaches. It is demonstrated that the MBPT-QED scheme, when carried to all orders, leads to a Schroedinger-like equation, equivalent to the Bethe-Salpeter (BS) equation. A Bloch equation in commutator form that can be used for an "extended" or quasi-degenerate model space is derived. It has the same relation to the BS equation as has the standard Bloch equation to the ordinary Schroedinger equation and can be used to generate a perturbation expansion compatible with the BS equation also for a quasi-degenerate model space.Comment: Submitted to Canadian J of Physic

A Bose-Einstein Approach to the Random Partitioning of an Integer

Consider N equally-spaced points on a circle of circumference N. Choose at random n points out of $N$ on this circle and append clockwise an arc of integral length k to each such point. The resulting random set is made of a random number of connected components. Questions such as the evaluation of the probability of random covering and parking configurations, number and length of the gaps are addressed. They are the discrete versions of similar problems raised in the continuum. For each value of k, asymptotic results are presented when n,N both go to infinity according to two different regimes. This model may equivalently be viewed as a random partitioning problem of N items into n recipients. A grand-canonical balls in boxes approach is also supplied, giving some insight into the multiplicities of the box filling amounts or spacings. The latter model is a k-nearest neighbor random graph with N vertices and kn edges. We shall also briefly consider the covering problem in the context of a random graph model with N vertices and n (out-degree 1) edges whose endpoints are no more bound to be neighbors

A scalable parallel finite element framework for growing geometries. Application to metal additive manufacturing

This work introduces an innovative parallel, fully-distributed finite element framework for growing geometries and its application to metal additive manufacturing. It is well-known that virtual part design and qualification in additive manufacturing requires highly-accurate multiscale and multiphysics analyses. Only high performance computing tools are able to handle such complexity in time frames compatible with time-to-market. However, efficiency, without loss of accuracy, has rarely held the centre stage in the numerical community. Here, in contrast, the framework is designed to adequately exploit the resources of high-end distributed-memory machines. It is grounded on three building blocks: (1) Hierarchical adaptive mesh refinement with octree-based meshes; (2) a parallel strategy to model the growth of the geometry; (3) state-of-the-art parallel iterative linear solvers. Computational experiments consider the heat transfer analysis at the part scale of the printing process by powder-bed technologies. After verification against a 3D benchmark, a strong-scaling analysis assesses performance and identifies major sources of parallel overhead. A third numerical example examines the efficiency and robustness of (2) in a curved 3D shape. Unprecedented parallelism and scalability were achieved in this work. Hence, this framework contributes to take on higher complexity and/or accuracy, not only of part-scale simulations of metal or polymer additive manufacturing, but also in welding, sedimentation, atherosclerosis, or any other physical problem where the physical domain of interest grows in time

'Raising the bar' : improving the standard and utility of weed and invasive plant research

Fil: Murray, Justine V.. Water for Healthy Country Flagship; AustraliaFil: Lehnhoff, Erik A.. Montana State University; Estados UnidosFil: Neve, Paul. University of Warwick; Reino UnidoFil: Poggio, Santiago Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Webber, Bruce L.. CSIRO Ecosystems Sciences; Australia. The University of Western Australia; Australi