Search results for "Graph theory"
showing 10 items of 784 documents
Iterative Reconstruction of Signals on Graph
2020
We propose an iterative algorithm to interpolate graph signals from only a partial set of samples. Our method is derived from the well known Papoulis-Gerchberg algorithm by considering the optimal value of a constant involved in the iteration step. Compared with existing graph signal reconstruction algorithms, the proposed method achieves similar or better performance both in terms of convergence rate and computational efficiency.
PORE Algorithm for Object Recognition in Photo Layers based on Parametric Characteristics of the Object Edges
2016
PORE stands for Photo-Object Recognition based on the Edges. Coincidentally, PORE means to examine something carefully and with due attention, so "we pore over the object layers in search for information about their characteristics with the aim at improving image recognition process". Therefore, this study presents a novel approach to object recognition based on the pattern by using photo layers and by defining the objects' specific characteristics. We select and introduce the parameters which determine a higher efficiency of image retrieval of the image objects. In this paper, we describe how the same photos are recognized in a process of classical retrieval compared to our model by analyz…
Detection of a reservoir water level using shape similarity metrics
2017
The matching between reservoirs’ water edge and digital elevation model’s (DEM) contour lines allowed determining the water level at the acquisition date of satellite images. A preliminary study was conducted on the Castello dam (Magazzolo Lake), between Alessandria della Rocca and Bivona (Agrigento, south-Italy). The accuracy assessment of the technique was than evaluated from the comparison between classified and reference objects using similarity metrics about the shape, theme, edge and position, through the plugin STEP of open source software GIS. Moreover, an independent GIS technique was implemented to evaluate the water level, based on a distances’ array between existing contour line…
Homeomorphic graph manifolds: A contribution to the μ constant problem
1999
Abstract We give a characterization, in terms of homological data in covering spaces, of those maps between (3-dimensional) graph manifolds which are homotopic to homeomorphisms. As an application we give a condition on a cobordism between graph manifolds that guarantees that they are homeomorphic. This in turn is applied to give a partial result on the μ -constant problem in (complex) dimension three.
Inner Edge Drag by an Asynchronous Primary and Accretion Disc Structure In Close Binaries
1996
In this work a 3-D ‘Smoothed Particle Hydrodynamics’ ([1]; [4]; [5]) accretion disc is simulated where particles at its inner edge are dragged by a fast spinning compact central star, as in the case of the intermediate polars. The angular velocity of the central star is twice the orbital angular velocity w 0. This drag can be attributed mainly to viscous interaction in the dense compact star atmosphere, although magnetic coupling may also play a role.
Correlations among Game of Thieves and other centrality measures in complex networks
2021
Social Network Analysis (SNA) is used to study the exchange of resources among individuals, groups, or organizations. The role of individuals or connections in a network is described by a set of centrality metrics which represent one of the most important results of SNA. Degree, closeness, betweenness and clustering coefficient are the most used centrality measures. Their use is, however, severely hampered by their computation cost. This issue can be overcome by an algorithm called Game of Thieves (GoT). Thanks to this new algorithm, we can compute the importance of all elements in a network (i.e. vertices and edges), compared to the total number of vertices. This calculation is done not in…
The Five-star Movement inside the institutions in Sicily: from ‘swimming the Strait’ to institutionalisation in local politics
2019
This article considers the institutionalisation of the Five-star Movement (M5s) in regional and local councils. It discusses the process of the Movement’s institutionalisation, analysing the development of its internal organisation; its local platforms and political performance; its institutional repertoire of action, and the several internal and external conflicts between its own rules and the ‘others’. In particular, the article investigates the changes affecting the M5s after its engagement with the Sicilian regional assembly and Sicilian municipal councils, and the ways in which the specific institutionalisation process it underwent was influenced by the complexities of the political an…
Unravelling green regional industrial path development: Regional preconditions, asset modification and agency
2020
Abstract Regions across the world are searching for ways to fashion new green growth paths and to promote green shifts in mature industries. The article aims to explore conceptually and based on illustrative empirical examples from the literature how green restructuring unfolds in regions. We propose a framework that explicates how regional preconditions in form of pre-existing industrial structures, organisational support structures, institutional set-ups and natural assets are transformed into various types of green path development through agentic processes of asset modification.
Some reflections on Fuzzy Set Theory as an Experimental Science
2014
The aim of this paper is to open a critical discussion on the claim, recently presented in the community and especially heralded by Enric Trillas, that fuzzy logic should be seen as an “experimental science”. The first interesting aspect of such remark is whether and in which way such position has consequences on the real development of the research, or if it is simply a (different) way of looking at the same phenomenon. As a consequence, we investigate the possible connection to Zadeh’s distiction between Fuzzy logic in a restricted sense and in a general sense. We shall argue that Trillas’s claim not only strongly supports the necessity for such a distinction, but provides a path of inves…
A topology-constrained distance network algorithm for protein structure determination from NOESY data.
2005
This article formulates the multidi- mensional nuclear Overhauser effect spectroscopy (NOESY) interpretation problem using graph theory and presents a novel, bottom-up, topology-con- strained distance network analysis algorithm for NOESY cross peak interpretation using assigned resonances. AutoStructure is a software suite that implements this topology-constrained distance net- work analysis algorithm and iteratively generates structures using the three-dimensional (3D) protein structure calculation programs XPLOR/CNS or DY- ANA. The minimum input for AutoStructure in- cludes the amino acid sequence, a list of resonance assignments, and lists of 2D, 3D, and/or 4D-NOESY cross peaks. AutoStru…