1,318 research outputs found
Coverage and Connectivity in Three-Dimensional Networks
Most wireless terrestrial networks are designed based on the assumption that
the nodes are deployed on a two-dimensional (2D) plane. However, this 2D
assumption is not valid in underwater, atmospheric, or space communications. In
fact, recent interest in underwater acoustic ad hoc and sensor networks hints
at the need to understand how to design networks in 3D. Unfortunately, the
design of 3D networks is surprisingly more difficult than the design of 2D
networks. For example, proofs of Kelvin's conjecture and Kepler's conjecture
required centuries of research to achieve breakthroughs, whereas their 2D
counterparts are trivial to solve. In this paper, we consider the coverage and
connectivity issues of 3D networks, where the goal is to find a node placement
strategy with 100% sensing coverage of a 3D space, while minimizing the number
of nodes required for surveillance. Our results indicate that the use of the
Voronoi tessellation of 3D space to create truncated octahedral cells results
in the best strategy. In this truncated octahedron placement strategy, the
transmission range must be at least 1.7889 times the sensing range in order to
maintain connectivity among nodes. If the transmission range is between 1.4142
and 1.7889 times the sensing range, then a hexagonal prism placement strategy
or a rhombic dodecahedron placement strategy should be used. Although the
required number of nodes in the hexagonal prism and the rhombic dodecahedron
placement strategies is the same, this number is 43.25% higher than the number
of nodes required by the truncated octahedron placement strategy. We verify by
simulation that our placement strategies indeed guarantee ubiquitous coverage.
We believe that our approach and our results presented in this paper could be
used for extending the processes of 2D network design to 3D networks.Comment: To appear in ACM Mobicom 200
Design-only conceptual design report for pit disassembly and conversion facility. Rev 0
This design-only conceptual design report (DOCDR) was prepared to support a funding request by the Department of Energy (DOE)-Office of Fissile Material Disposition (OFMD) for engineering design of the Pit Disassembly and Conversion Facility (PDCF) Project No. 99-D-141. The PDCF will be used to disassemble the nation`s inventory of surplus nuclear weapons pits and convert the plutonium recovered from those pits into a form suitable for storage, international inspection, and final disposition. The PDCF is a complex consisting of a hardened building that will contain the plutonium processes in a safe and secure manner, and conventional buildings and structures that will house support personnel, systems, and equipment. The PDCF uses the Advanced Recovery and Integrated Extraction System (ARIES), a low waste, modular pyroprocessing system to convert pits to plutonium oxide. The PDCF project consists of engineering and design, and construction of the buildings and structures, and engineering and design, procurement, installation, testing and start-up of equipment to disassemble pits and convert plutonium in pits to oxide form. The facility is planned to operate for 10 years, averaging 3.5 metric tons (3.86 tons) of plutonium metal per year. On conclusion of operations, the PDCF will be decontaminated and decommissioned
Analysis of roles and groups in blogosphere
In the paper different roles of users in social media, taking into
consideration their strength of influence and different degrees of
cooperativeness, are introduced. Such identified roles are used for the
analysis of characteristics of groups of strongly connected entities. The
different classes of groups, considering the distribution of roles of users
belonging to them, are presented and discussed.Comment: 8th International Conference on Computer Recognition Systems, CORES
201
Automatic method for the dermatological diagnosis of selected hand skin features in hyperspectral imaging
Introduction: Hyperspectral imaging has been used in dermatology for many years.
The enrichment of hyperspectral imaging with image analysis broadens considerably
the possibility of reproducible, quantitative evaluation of, for example, melanin and
haemoglobin at any location in the patient's skin. The dedicated image analysis
method proposed by the authors enables to automatically perform this type of
measurement.
Material and method: As part of the study, an algorithm for the analysis of
hyperspectral images of healthy human skin acquired with the use of the Specim
camera was proposed. Images were collected from the dorsal side of the hand. The
frequency λ of the data obtained ranged from 397 to 1030 nm. A total of 4'000 2D
images were obtained for 5 hyperspectral images. The method proposed in the
paper uses dedicated image analysis based on human anthropometric data,
mathematical morphology, median filtration, normalization and others. The algorithm
was implemented in Matlab and C programs and is used in practice.
Results: The algorithm of image analysis and processing proposed by the authors
enables segmentation of any region of the hand (fingers, wrist) in a reproducible
manner. In addition, the method allows to quantify the frequency content in
different regions of interest which are determined automatically. Owing to this, it is
possible to perform analyses for melanin in the frequency range λE∈(450,600) nm
and for haemoglobin in the range λH∈(397,500) nm extending into the ultraviolet for
the type of camera used. In these ranges, there are 189 images for melanin and 126
images for haemoglobin. For six areas of the left and right sides of the little finger
(digitus minimus manus), the mean values of melanin and haemoglobin content
were 17% and 15% respectively compared to the pattern.
Conclusions: The obtained results confirmed the usefulness of the proposed new
method of image analysis and processing in dermatology of the hand as it enables
reproducible, quantitative assessment of any fragment of this body part. Each image
in a sequence was analysed in this way in no more than 100 ms using Intel Core i5
CPU M460 @2.5 GHz 4 GB RAM
Brief for the Respondents, \u3cem\u3eTVA v. Hill\u3c/em\u3e, No. 76-1701
Brief for the respondents in the case of Tennessee Valley Authority v. Hiram G. Hill Jr., et al., heard by the United States Supreme Court in the October Term of 1977
Multicomponent ceramic materials on the basis of PZT for the production of piezoelectric resonators
Investigations on the influence of the PbTiO3 content on the crystalline and domain structure of PZT-based four-component solid solutions have been performed. It has been shown that there is a close relation between the structure and temperature stability of the resonance frequency (fr) of the fabricated piezoceramic transducers. Better and more stable results have been obtained by doping and modifying the basic chemical composition obtaining Pb(Zr1¡xTix)O3. The compositions with minimal ¢fr=fr, within the temperature range T = 213–358 K (in relation to room temperature Tr = 293 K), exhibited (i) the smallest internal friction
(Q¡1 m ), (ii) the highest mechanical quality (Qm), (iii) high values of spontaneous deformation
of the elementary cell (±T and ±Re), (iv) the complex a-c-domain structure in the tetragonal
phase (T) and the simple domain structure in the rhombohedral phase (Re).
The practical result of the present work was the fabrication of piezoceramic electric band
filters exhibiting ¢fr=fr < 0:2% and a high mechanical quality factor (Qm = 3225)
Bond for Costs on Appeal, \u3cem\u3eTVA v. Hill et al\u3c/em\u3e, Civil Action No. 3-76-48
Bond for costs on appeal, in the case of TVA v. Hill et al, United States District Court for the Eastern District of Tennessee, Northern Divisio
The genome sequence of Brucella pinnipedialis B2/94 sheds light on the evolutionary history of the genus Brucella
International audienceBackground: Since the discovery of the Malta fever agent, Brucella melitensis, in the 19th century, six terrestrial mammal-associated Brucella species were recognized over the next century. More recently the number of novel Brucella species has increased and among them, isolation of species B. pinnipedialis and B. ceti from marine mammals raised many questions about their origin as well as on the evolutionary history of the whole genus. Results: We report here on the first complete genome sequence of a Brucella strain isolated from marine mammals, Brucella pinnipedialis strain B2/94. A whole gene-based phylogenetic analysis shows that five main groups of host-associated Brucella species rapidly diverged from a likely free-living ancestor close to the recently isolated B. microti. However, this tree lacks the resolution required to resolve the order of divergence of those groups. Comparative analyses focusing on a) genome segments unshared between B. microti and B. pinnipedialis, b) gene deletion/fusion events and c) positions and numbers of Brucella specific IS711 elements in the available Brucella genomes provided enough information to propose a branching order for those five groups. Conclusions: In this study, it appears that the closest relatives of marine mammal Brucella sp. are B. ovis and Brucella sp. NVSL 07-0026 isolated from a baboon, followed by B. melitensis and B. abortus strains, and finally the group consisting of B. suis strains, including B. canis and the group consisting of the single B. neotomae species. We were not able, however, to resolve the order of divergence of the two latter groups
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