Search results for " Computer Science"
showing 10 items of 3983 documents
Automated Characterization of Mouth Activity for Stress and Anxiety Assessment
2016
International audience; Non-verbal information portrayed by human facial expression, apart from emotional cues also encompasses information relevant to psychophysical status. Mouth activities in particular have been found to correlate with signs of several conditions; depressed people smile less, while those in fatigue yawn more. In this paper, we present a semi-automated, robust and efficient algorithm for extracting mouth activity from video recordings based on Eigen-features and template-matching. The algorithm was evaluated for mouth openings and mouth deformations, on a minimum specification dataset of 640x480 resolution and 15 fps. The extracted features were the signals of mouth expa…
Comparative Study of the Mobile Learning Architectures
2016
International audience; With the emergence of mobile devices (Smart Phone, PDA, UMPC, game consoles, etc.), learning is changing from electronic learning (e-Learning) to mobile learning (m-learning). In fact, due to the mobility feature, it seems that the m-learning have to be adapted with the change within the context. Several researches addressed this issue and implemented a mobile learning environment to prove its usefulness and feasibility in various domains. In this article, we conduct a comparative study between a list of mobile learning architectures and methods that are presented in the literature. The performance of these architectures is evaluated based on several criteria, such a…
Privacy in Big Data
2016
International audience
Overlapping community detection versus ground-truth in AMAZON co-purchasing network
2015
International audience; Objective evaluation of community detection algorithms is a strategic issue. Indeed, we need to verify that the communities identified are actually the good ones. Moreover, it is necessary to compare results between two distinct algorithms to determine which is most effective. Classically, validations rely on clustering comparison measures or on quality metrics. Although, various traditional performance measures are used extensively. It appears very clearly that they cannot distinguish community structures with different topological properties. It is therefore necessary to propose an alternative methodology more sensitive to the community structure variations in orde…
Intelligence Level Performance Standards Research for Autonomous Vehicles
2015
International audience; United States and European safety standards have evolved to protect workers near AutomaticGuided Vehicles (AGVs). However, performance standards for AGVs and mobile robots have only recently begun development. Lessons can be learned from research and standards effortsfor mobile robots applied to emergency response and military applications. Research challenges, tests and evaluations, and programs to develop higher intelligencelevelsfor vehicles can also be used to guide industrial AGV developments towards more adaptable and intelligent systems. These other efforts also provide useful standards development criteria for AGV performance test methods. Current standards a…
Extending CSG with projections: Towards formally certified geometric modeling
2015
We extend traditional Constructive Solid Geometry (CSG) trees to support the projection operator. Existing algorithms in the literature prove various topological properties of CSG sets. Our extension readily allows these algorithms to work on a greater variety of sets, in particular parametric sets, which are extensively used in CAD/CAM systems. Constructive Solid Geometry allows for algebraic representation which makes it easy for certification tools to apply. A geometric primitive may be defined in terms of a characteristic function, which can be seen as the zero-set of a corresponding system along with inequality constraints. To handle projections, we exploit the Disjunctive Normal Form,…
Interpreting Heterogeneous Geospatial Data Using Semantic Web Technologies
2016
International audience; The paper presents work on implementation of semantic technologies within a geospatial environment to provide a common base for further semantic interpretation. The work adds on the current works in similar areas where priorities are more on spatial data integration. We assert that having a common unified semantic view on heterogeneous datasets provides a dimension that allows us to extend beyond conventional concepts of searchability, reusability, composability and interoperability of digital geospatial data. It provides contextual understanding on geodata that will enhance effective interpretations through possible reasoning capabilities. We highlight this through …
Maximum likelihood difference scaling of image quality in compression-degraded images.
2007
International audience; Lossy image compression techniques allow arbitrarily high compression rates but at the price of poor image quality. We applied maximum likelihood difference scaling to evaluate image quality of nine images, each compressed via vector quantization to ten different levels, within two different color spaces, RGB and CIE 1976 L(*)a(*)b(*). In L(*)a(*)b(*) space, images could be compressed on average by 32% more than in RGB space, with little additional loss in quality. Further compression led to marked perceptual changes. Our approach permits a rapid, direct measurement of the consequences of image compression for human observers.
k-Partite Graphs as Contexts
2018
International audience; In formal concept analysis, 2-dimensional formal contexts are bipar-tite graphs. In this work, we generalise the notions of context and concept to graphs that are not bipartite. We then study the complexity of the enumeration and identify the structure of the set of such concepts.
Fuzzy formalizations of cognitive distance
1992
Spatial training process allows more and more precise informations to be collected and memorized. The aim of this article is to describe a three steps training process based on three fuzzy formalizations of cognitive distance associated to three different types of informations : (1) expression of a linguistic relative distance based on fuzzy relation of closeness or/and remoteness, (2) expression of a linguistic absolute distance expressed by primary linguistic terms like short or long and (3) expression of a fuzzy metric absolute distance. A fourth part is devoted to expression of precise correspondance rule between linguistic and metric opinions described below.