Search results for "image processing"
showing 10 items of 3285 documents
Exploratory approach for network behavior clustering in LoRaWAN
2021
AbstractThe interest in the Internet of Things (IoT) is increasing both as for research and market perspectives. Worldwide, we are witnessing the deployment of several IoT networks for different applications, spanning from home automation to smart cities. The majority of these IoT deployments were quickly set up with the aim of providing connectivity without deeply engineering the infrastructure to optimize the network efficiency and scalability. The interest is now moving towards the analysis of the behavior of such systems in order to characterize and improve their functionality. In these IoT systems, many data related to device and human interactions are stored in databases, as well as I…
Real-Time Temporal Superpixels for Unsupervised Remote Photoplethysmography
2018
International audience; Segmentation is a critical step for many computer vision applications. Among them, the remote photoplethys-mography technique is significantly impacted by the quality of region of interest segmentation. With the heart-rate estimation accuracy, the processing time is obviously a key issue for real-time monitoring. Recent face detection algorithms can perform real-time processing, however for unsupervised algorithms, i.e. without any subject detection based on supervised learning, existing methods are not able to achieve real-time on regular platform. In this paper, we propose a new method to perform real-time un-supervised remote photoplethysmograhy based on efficient…
A non-parametric segmentation methodology for oral videocapillaroscopic images
2014
We aim to describe a new non-parametric methodology to support the clinician during the diagnostic process of oral videocapillaroscopy to evaluate peripheral microcirculation. Our methodology, mainly based on wavelet analysis and mathematical morphology to preprocess the images, segments them by minimizing the within-class luminosity variance of both capillaries and background. Experiments were carried out on a set of real microphotographs to validate this approach versus handmade segmentations provided by physicians. By using a leave-one-patient-out approach, we pointed out that our methodology is robust, according to precision-recall criteria (average precision and recall are equal to 0.9…
Effects and Benefits of Node Sharing Strategies in HPC Batch Systems
2019
Processor manufacturers today scale performance by increasing the number of cores on each CPU. Unfortunately, not all HPC applications can efficiently saturate all cores of a single node, even if they successfully scale to thousands of nodes. For these applications, sharing nodes with other applications can help to stress different resources on the nodes to more efficiently use them. Previous work has shown that the performance impact of node sharing is very application dependent but very little work has studied its effects within batch systems and for complex parallel application mixes. Administrators therefore typically fear the complexity of running a batch system supporting node sharing…
A task scheduling algorithm for HPC applications using colored stochastic Petri Net models
2017
The increase in demand for High Performance Computing (HPC) scientific applications motivates the efforts to reduce costs of running these applications. The problem to solve is that of dynamical multi-criterial optimal scheduling of an application on a HPC platform with a high number of heterogeneous nodes. The solution proposed by the authors is a HPC hardware-software architecture that includes the infrastructure for two level (node and inter-node level) adaptive load balancing. The article presents the development of an Coloured Petri Net(CPN) for such an architecture. The model was used for the development of a dynamic distributed algorithm for the scheduling problem. The CPN allowed a …
Operational cloud screening service for Sentinel-2 image time series
2015
This paper deals with the development and implementation of a cloud screening algorithm for image time series, with the focus on the forthcoming Sentinel-2 satellites to be launched under the ESA Copernicus Programme. The proposed methodology is based on kernel ridge regression and exploits the temporal information to detect anomalous changes that correspond to cloud covers. The huge data volumes to be processed when dealing with high temporal, spatial, and spectral resolution datasets motivate the implementation of the algorithm within distributed computer resources. In consequence, an operational cloud screening service has been specifically designed and implemented in the frame of the Se…
Kernel Based Symmetry Measure
2005
In this paper we concentrate on a measure of symmetry. Given a transform S, the kernel SK of a pattern is defined as the maximal included symmetric sub-set of this pattern. A first algorithm is outlined to exhibit this kernel. The maximum being taken over all directions, the problem arises to know which center to use. Then the optimal direction triggers the shift problem too. As for the measure we propose to compute a modified difference between respective surfaces of a pattern and its kernel. A series of experiments supports actual algorithm validation.
Combined fuzzy TOPSIS and AHP-based methodology for the prioritization of maintenance key performance indicators: Application to an oil refinery plant
2017
A Maintenance Performance Measurement model based on the use of Maintenance Key Performance Indicators (MKPIs) is proposed in the present paper. Referring to a specific industrial context, a multi-level hierarchical structure is firstly designed to highlight the most meaningful perspectives which affect the maintenance performance. Then, MKPIs selected from the literature or properly formulated to detail some particular perspective of the investigated maintenance process are assigned to the hierarchical framework and prioritized by a Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (FTOPSIS) and Analytic Hierarchy Process (AHP)-based approach.
Analysis of nonlinear coupling on the behavior of the sine-Gordon and Klein-Gordon models in bandwidth and forbidden bands
2017
In this thesis, we analyze the conditions of existence of the phenomenon of nonlinear supratransmission in two different models: a modified fifth-order Klein-Gordon system and a modified sine-Gordon system. The modified models considered here are those with mixed coupling, the pure linear coupling being associated with a nonlinear coupling. In particular, we quantify numerically the influence of the non-linear coupling coefficient on the threshold amplitude which triggers the phenomenon of non-linear supratransmission. Our main result shows that in both models, when the nonlinear coupling coefficient increases, the threshold amplitude triggering the phenomenon of nonlinear supratransmission…
Cloud Based Cross-system Integration for Small and Medium-sized Enterprises
2017
The usage of information technology (IT) is one of the major factors for ensuring the growth and competitiveness of enterprises, as well as it also benefits the effective knowledge management within the organisation.There are large-scale knowledge management systems (KMS) covering the full functionality for facilitating the effectiveness and productivity of employees. These systems are frequently integrated into other organisation's management systems. But the most of the small and medium-sized enterprises (SMEs) cannot afford to use these KMS, and also the full functionality of these KMS is not necessary for them. Thus, the solution is to combine the parts of cloud based knowledge manageme…