Search results for "Computer science"
showing 10 items of 22367 documents
An Examination of Tourist Arrivals Dynamics Using Short-Term Time Series Data: A Space—Time Cluster Approach
2013
The purpose of this study is to examine the development of Italian tourist areas ( circoscrizioni turistiche) through a cluster analysis of short time series. The technique is an adaptation of the functional data analysis approach developed by Abraham et al (2003), which combines spline interpolation with k-means clustering. The findings indicate the presence of two patterns (increasing and stable) averagely characterizing groups of territories. Moreover, tests of spatial contiguity suggest the presence of ‘space–time clusters’; that is, areas in the same ‘time cluster’ are also spatially contiguous. These findings appear to be more robust in particular for those series characterized by an…
Aliasing-Free and Additive Error in Mixed Spectra for Stable Processes. Application: Sound of a Bird just captivated in stress
2022
Consider a symmetric continuous time α stableprocess observed with an additive constant error. Theobjective of this paper is to give a non-parametric estimatorof this error by using discrete observations. As the time ofprocess is continuous and the observations are discrete, weencountered the aliasing phenomenon. Our process sampleis taken in a way to circumvent the difficulty related toaliasing and we smoothed the periodogram by using JacksonKernel. The rate of convergence of this estimator is studiedwhen the spectral density is zero at origin. Few long memoryprocesses are taken here as examples. We have applied ourestimator to the concrete case of modeling noise of a birdcaptured under st…
A Proposal of Process Fragment Definition and Documentation
2012
This paper focuses on the field of Situational Method Engineering (SME) for the construction of agent-oriented design processes. Whatever SME approach a method designer wants to use, he has to manage two main elements: the (method or process) fragment and the repository where it is stored. Specific fragment definition and documentation are fundamental during these activities, for new process composition, and for the consequent system design activities. This paper aims at illustrating a proposal of fragment definition and documentation. This proposal is aimed to be an input for the IEEE FIPA Design Process Documentation and Fragmentation working group and, as regards our own research work, t…
Leveraging Users' Likes in a Video Streaming P2P Platform
2014
This paper investigates how a p2p television platform can take advantage of the presence of frequent channel viewers to grant them a more satisfying service than to less regular spectators. The idea we explore is to learn beforehand about the users' interests, in order to cluster them in groups that display different behaviors; then, the neighborhood creation strategy and video chunk scheduling algorithm of the overlay is altered, with the aim of serving frequent spectators in a privileged manner, providing them with a faster access to the selected channel without overly penalizing less habitual customers. An analytical model is developed, to capture the difference in startup delay that the…
Kinematic and Elastostatic Design Optimisation of the 3-DOF Gantry-Tau Parallel Kinematic Manipulator
2009
Published version of an article in the journal: Modeling Identification and Control. Also available from the publisher:http://dx.doi.org/10.4173/mic.2009.2.1 One of the main advantages of the Gantry-Tau machine is a large accessible workspace/footprint ratio compared to many other parallel machines. The Gantry-Tau improves this ration further by allowing a change of assembly mode without internal link collisions or collisions between the links and end-effector. The reconfigurable Gantry-Tau kinematic design obtained by multi-objective optimisation according to this paper gives the following features: 3-D workspace/footprint ration is more than 3.19, lowest Cartesian stiffness in the workspa…
Using uncertain preferential information from stakeholders to assess the acceptability of alternative forest management plans
2017
In forest management planning, participatory planning processes are often encouraged as a means to acquire relevant information and to enhance the stakeholders' acceptability of alternative plans. This requires the aggregation of the stakeholders' preferences that can be done in a wide variety of manners. The aggregation process strives to reduce the information into a single set of preferences that simplifies the information and allows for the use of discrete decision support tools. Depending on how the preferences are aggregated, a wide range of plan rankings can emerge. Although this range of ranking complicates the issue of plan selection, it does highlight the uncertainty involved in a…
Stability of stochastic nonlinear systems with state-dependent switching
2013
In this paper, the problem of stability on stochastic systems with state-dependent switching is investigated. To analyze properties of the switched system by means of Itô’s formula and Dynkin’s formula, it is critical to show switching instants being stopping times. When the given active-region set can be replaced by its interior, the local solution of the switched system is constructed by defining a series of stopping times as switching instants, and the criteria on global existence and stability of solution are presented by Lyapunov approach. For the case where the active-region set can not be replaced by its interior, the switched systems do not necessarily have solutions, thereby quasi-…
Conception de documents numériques : Parcours méthodologique
2009
There is a strong social demand for studies of digital document. Yet our models of society and education are struggling to integrate issues related to these types of documents. However, the subject is less than half a century old, and so it is hardly surprising that the writing and training practices are just being developed. Like the book, the digital document involves many different skills and techniques in its development. The list of jobs tends to grow steadily: ergonomists, referencing specialists, information architects, programmers, designers, integrators ... It is therefore difficult to have a global view on all this know-how and the related methodologies. This special edition seeks…
Définir la structure de navigation : quelques outils méthodologiques
2008
On peut distinguer deux niveaux de structuration des documents numériques. Ces deux niveaux correspondent aussi à deux niveaux de découpage de l'information. le niveau «macro» correspond au découpage de l'information d'un domaine en différentes unités d'informations (écrans). Le niveau inférieur, ou « micro » correspond au découpage de l'information en concept sur chaque écran. Par « macro structuration », on entend donc la structuration du document qui n'est pas forcément visible par l'utilisateur mais qui est perceptible lors des déplacements en son sein. L'objectif de cette structuration est de proposer une arborescence, qui corresponde à l'objet du document numérique. Deux principaux ob…
Primitives extraction based on structured-light images
2013
International audience; Geometric attributes such as curvature or surface orientation are additional information of the 3D points obtained after the scanning of an object. In the classic 3D chain, characterized by a sequential structure, these information are determined from the dense point cloud (from a 3D scanner). Then, they are used to reduce the amount of information and allows to obtain a simplified model. In this paper, we investigate the possibility to extract some geometric attributes, directly from 2D images obtained by the camera of a structured-light system.