Search results for "General Computer Science"
showing 10 items of 895 documents
Averaging and optimal control of elliptic Keplerian orbits with low propulsion
2006
This article deals with the optimal transfer of a satellite between Keplerian orbits using low propulsion. It is based on preliminary results of Geffroy [Generalisation des techniques de moyennation en controle optimal, application aux problemes de rendez-vous orbitaux a poussee faible, Ph.D. Thesis, Institut National Polytechnique de Toulouse, France, Octobre 1997] where the optimal trajectories are approximated using averaging techniques. The objective is to introduce the appropriate geometric framework and to complete the analysis of the averaged optimal trajectories for energy minimization, showing in particular the connection with Riemannian problems having integrable geodesics.
Design of a Real-time face detection parallel architecture using High-Level Synthesis
2008
Abstract We describe a High-Level Synthesis implementation of a parallel architecture for face detection. The chosen face detection method is the well-known Convolutional Face Finder (CFF) algorithm, which consists of a pipeline of convolution operations. We rely on dataflow modelling of the algorithm and we use a high-level synthesis tool in order to specify the local dataflows of our Processing Element (PE), by describing in C language inter-PE communication, fine scheduling of the successive convolutions, and memory distribution and bandwidth. Using this approach, we explore several implementation alternatives in order to find a compromise between processing speed and area of the PE. We …
Coding Partitions
2007
Motivated by the study of decipherability conditions for codes weaker than Unique Decipherability (UD), we introduce the notion of coding partition. Such a notion generalizes that of UD code and, for codes that are not UD, allows to recover the ''unique decipherability" at the level of the classes of the partition. By tacking into account the natural order between the partitions, we define the characteristic partition of a code X as the finest coding partition of X. This leads to introduce the canonical decomposition of a code in at most one unambiguous component and other (if any) totally ambiguous components. In the case the code is finite, we give an algorithm for computing its canonical…
Developing a framework for designing humanitarian blockchain projects
2021
International audience; Blockchain technology promises to improve the efficiency, transparency, and accountability of humanitarian operations. Yet at the same time, especially the humanitarian context with its characteristic volatility poses unique challenges to any technology. Most prominent are the humanitarian principles that are fundamental to humanitarian operations. These ethical principles are set to protect the most vulnerable populations. Designing blockchain projects in the humanitarian context therefore requires a systematic framework that helps humanitarians make critical choices.While some design instructions can be found for commercial applications, the humanitarian context re…
What makes the difference : PIAAC as a resource for understanding the problem-solving skills of Europe's higher-education adults
2019
The ever-evolving technological landscape is challenging adults' problem-solving skills. The central goal of higher education (HE) is to guarantee a high level of know-how, which is in line with the changing demands of technology at work and in everyday life. This study builds on European data from the Programme for the International Assessment of Adult Competencies (PIAAC) to understand adults' (N = 53,407) skills for solving problems in technology-rich environments. The study provides insight into the socio-demographic, work-related, and everyday factors that are associated with a strong and a weak problem-solving performance. The results indicate that HE adults stand out from adults with…
Le développement des médias sociaux. Proposition d'un modèle de diffusion intégrant les externalités de réseau dans un cadre concurrentiel
2011
International audience; La fréquentation des médias sociaux est très concentrée. L’intérêt de ce type de sites résidant dans la richesse du contenu élaboré par les participants, ce phénomène peut être en partie expliqué par les externalités de réseau. Afin de démontrer cet effet dans un cadre concurrentiel, cette recherche propose un modèle de diffusion intégrant le principe de l’attachement préférentiel issu des recherches en réseaux complexes. Ce modèle est analysé au travers d’une simulation et appliqué à 51 médias sociaux dans trois secteurs différents. Les résultats montrent que l’ajout de l’effet d’attraction menée par la taille relative du réseau social explique mieux la diffusion qu…
The b-chromatic number of power graphs
2003
The b-chromatic number of a graph G is defined as the maximum number k of colors that can be used to color the vertices of G, such that we obtain a proper coloring and each color i, with 1 ≤ i≤ k, has at least one representant x_i adjacent to a vertex of every color j, 1 ≤ j ≠ i ≤ k. In this paper, we discuss the b-chromatic number of some power graphs. We give the exact value of the b-chromatic number of power paths and power complete binary trees, and we bound the b-chromatic number of power cycles.
Network Capacity Estimators Predicting QoE in HTTP Adaptive Streaming
2022
The aim of adaptive HTTP streaming technology is preserving the best possible video streaming quality for viewers in heterogeneous network conditions. This can be achieved by making multiple quality versions of the video available. Switching between versions during playback should be imperceptible and fluent. The decision about quality-level switching is typically based on network capacity estimation and buffer occupancy, which predict the risk of stalling. Since quality-level switching and stalling are directly evident to the user, they are often classified as influence factors of quality of experience (QoE). In this paper, we observe different network capacity estimators and buffer behavi…
A Survey on Technologies Which Make Bitcoin Greener or More Justified
2022
According to recent estimates, one bitcoin transaction consumes as much energy as 1.5 million Visa transactions. Why is bitcoin using so much energy? Most of the energy is used during the bitcoin mining process, which serves at least two significant purposes: a) distributing new cryptocurrency coins to the cryptoeconomy and b) securing the Bitcoin blockchain ledger. In reality, the comparison of bitcoin transactions to Visa transactions is not that simple. The amount of transactions in the Bitcoin network is not directly connected to the amount of bitcoin mining power nor the energy consumption of those mining devices; for example, it is possible to multiply the number of bitcoin transactio…
L'impact de la substitution de marques sur l'évaluation et l'intention d'achat du produit.
2008
L'objectif de cet article est de comprendre l'impact de la substitution de marques sur l'évaluation et l'intention d'achat du produit. À cette fin, les différents types de substitutions de marques sont présentés. Puis, à partir des travaux relatifs à l'extension de marque et au co-marquage, des variables susceptibles d'expliquer l'évolution de l'évaluation et de l'intention d'achat d'un produit qui a changé de nom de marque sont proposées. L'étude empirique met en évidence que cinq variables influencent l'évolution de l'évaluation et de l'intention d'achat du produit qui a changé de nom de marque: (1) la similarité entre la marque de substitution et la marque initiale, (2) la cohérence per…