Search results for "topology."
showing 10 items of 2840 documents
A Restricted-Weakly Connected Dominating Set for Role Assignment in a Multichannel MAC for Wireless Mesh Network
2009
International audience; We propose an efficient way of constructing the wireless mesh structure associated with Molecular MAC, a multichannel access method designed for efficient packet forwarding. We base our role assignment on a restricted Weakly Connected Dominating Set structure. After presenting a formal definition of the role assignment problem, we prove its NP-completeness. Then, we propose a centralized 2-approximation algorithm that maximizes the sum of radio link capacities in the molecular structure. Finally, we extend this protocol so that it can operate in a distributed way still providing the same guarantee. This distributed protocol is self-stabilizing thus robust to topology…
MCD: Overcoming the Data Download Bottleneck in Data Centers
2013
The data download problem in data centers describes the increasingly common task of coordinated loading of identical data to a large number of nodes. Data download is seen as a significant problem in exascale HPC applications. Uncoor-dinated reading from a central file server creates contention at the file server and its network interconnect. We propose and evaluation a reliable multicast based approach to solve the data download problem. The MCD system builds a logical multi-rooted tree based on the physical network topology and uses the logical view for a two-phase approach. In the first phase, the data is multicasted to all nodes. In the second phase, the logical tree is used for an effi…
Asymmetries in path encoding in Sicilian: A diachronic overview
2017
This talk aims at describing the encoding of path within the system of spatial relations in Sicilian, an Italo-Romance language spoken in Sicily and its satellite islands. In general terms, spatial relations in Sicilian remain largely unexplored in the light of the current linguistic theories. As a consequence, the first point addressed in the proposed description is the comparison of Sicilian data with the cross-linguistic scenario. It is generally argued in the relevant literature that the encoding of path appears to be less autonomous compared to source, goal, and location at the cross-linguistic level, and its encoding is frequently based on location (see Stolz 1992). In Sicilian, the s…
Design and Investigation of a Touch Gesture for Dividing in a Virtual Manipulative Model for Equation-solving
2020
AbstractPhysical models for equation solving typically lack feedback regarding their appropriate use. Such feedback is possible in virtual environments and could be implemented in hybrid models. Based on an epistemological analysis, this article presents a touch gesture as a way for users to signal they want to divide both sides of an equation and a design for feedback on the use of this so-called ‘division gesture’. The design is investigated by contrasting a case study, in which students used an app with the division gesture, with a preparatory study where students had to perform corresponding actions on physical manipulatives. This investigation revealed insight into feedback functions, …
Decentralized Subspace Projection for Asymmetric Sensor Networks
2020
A large number of applications in Wireless Sensor Networks include projecting a vector of noisy observations onto a subspace dictated by prior information about the field being monitored. In general, accomplishing such a task in a centralized fashion, entails a large power consumption, congestion at certain nodes and suffers from robustness issues against possible node failures. Computing such projections in a decentralized fashion is an alternative solution that solves these issues. Recent works have shown that this task can be done via the so-called graph filters where only local inter-node communication is performed in a distributed manner using a graph shift operator. Most of the existi…
Comparative Analysis of Modified Modulation Scheme for Three-phase Voltage fed QZS Inverters
2019
Single-stage converters are one promising solution in different field of applications. In particular, quasi-Z-Source VSI topology structure playsan important role because it presents the same advantages of VSI and qZS converters. In addition, it allows increasing the inverter reliability. Moreover, modulation schemes and control strategy are still being developed. For this reason, aim of this paper is to introduce a modified modulation scheme based on the Maximum Constant Boost Control (MCBC) concept and Switching Frequency Optimal (SFO)as reference signals that represents the novelty issue of this work. The analysis has been carried out by comparing the performance of the converter in term…
Steerable wavelet transform for atlas based retinal lesion segmentation
2013
International audience; Computer aided diagnosis and follow up can help in prevention and treatment of diabetes and its related complications. Screening of diabetes related disease in the eyes is done by a special low cost fundus camera. A follow up of the patients visiting at di fferent time intervals for screening brings us to the problem of image analysis for change detection and its cost per patient. It is very likely that human annotations for the lesions may be erroneous and often time consuming. Since the ethnic background plays a signi cant role in retinal pigment epithelium, visibility of the choroidal vasculature and overall retinal luminance in patients and retinal images, an eth…
Modeling, analysis, and simulation of MIMO mobile-to-mobile fading channels
2008
This paper' deals with the modeling, analysis, and simulation of multiple-input multiple-output (MIMO) narrowband fading channels for mobile-to-mobile communications. A stochastic MIMO mobile-to-mobile reference channel model is derived from the geometrical two-ring scattering model under the assumption that both the transmitter and the receiver are surrounded by an infinite number of local scatterers. Using a wave propagation model, the complex channel gains are derived and their statistical properties are studied. General analytical solutions are provided for the three-dimensional (3-D) space-time cross-correlation function (CCF). We show that this function can be expressed as the product…
Multimode entanglement in reconfigurable graph states using optical frequency combs
2017
Multimode entanglement is an essential resource for quantum information processing and quantum metrology. However, multimode entangled states are generally constructed by targeting a specific graph configuration. This yields to a fixed experimental setup that therefore exhibits reduced versatility and scalability. Here we demonstrate an optical on-demand, reconfigurable multimode entangled state, using an intrinsically multimode quantum resource and a homodyne detection apparatus. Without altering either the initial squeezing source or experimental architecture, we realize the construction of thirteen cluster states of various sizes and connectivities as well as the implementation of a secr…
Recent Advances in Large-scale Structure Statistics
1997
I review the most recent redshift surveys used to probe the large scale structure of the Universe. Then I provide an overview of some of the statistical tools used to describe the galaxy distribution, trying to connect these measures with some of the statistics used in the mainstream of spatial statistics. Special topics include intensity functions, topology, and second-order statistics (2-point correlation function, K-function).