Search results for "engineering"
showing 10 items of 44231 documents
Atmospheric circulation modulates the spatial variability of temperature in the Atlantic-Arctic region
2019
International audience; The Arctic region has experienced significant warming during the past two decades with major implications on the cryosphere. The causes of Arctic amplification are still an open question within the scientific community, attracting recent interest. The goal of this study is to quantify the contribution of atmospheric circulation on temperature variability in the Atlantic–Arctic region at decadal to intra‐annual timescales from 1951 to 2014. Daily 20th Century reanalyses geopotential height anomalies at 500 hPa were clustered into different weather regimes to assess their contribution to observed temperature variability. The results show that in winter, 25% of the warm…
Webcam based display calibration
2012
International audience; We present an automatic method for measuring the tone response curve of display devices based on visual methods, where the eye is replaced by an end-user, uncalibrated camera, such as a webcam. Our approach compares a series of halftoned patches of known covering ratio with a continuous series of tone patches for each ratio. Both patches are shot by a camera that is used as a virtual eye to evaluate the luminance difference. By an iterative process, the continuous tone value is adjusted while compared with the perceived level of the halftoned patch. When the camera does not see any difference between the patches or a minimal difference, the luminance level of the con…
Practice for determining friction in hydraulic winch systems
2020
This paper presents a method for estimating friction in hydraulic active heave compensated (AHC) offshore winches. The method is a two-step approach where the first step is to model the friction loss in the hydraulic motors based on data from the sub-supplier. The second step requires real-life testing, where the remaining friction losses in the winch system is identified and modeled. In this context, a practice is characterized by obtaining a friction loss estimation with the highest possible accuracy over the widest possible range of operating conditions with a limited amount of experimental work. The method benefits from the use of parametric models, sub-supplier data, and real-life meas…
Estimation of wind velocity over a complex terrain using the Generalized Mapping Regressor
2010
Abstract Wind energy evaluation is an important goal in the conversion of energy systems to more environmentally friendly solutions. In this paper, we present a novel approach to wind speed spatial estimation on the isle of Sicily (Italy): an incremental self-organizing neural network (Generalized Mapping Regressor – GMR) is coupled with exploratory data analysis techniques in order to obtain a map of the spatial distribution of the average wind speed over the entire region. First, the topographic surface of the island was modelled using two different neural techniques and by exploiting the information extracted from a digital elevation model of the region. Then, GMR was used for automatic …
Olfactory identification capacities in novice and wine experts
2010
International audience
Learn to Cache: Machine Learning for Network Edge Caching in the Big Data Era
2018
The unprecedented growth of wireless data traffic not only challenges the design and evolution of the wireless network architecture, but also brings about profound opportunities to drive and improve future networks. Meanwhile, the evolution of communications and computing technologies can make the network edge, such as BSs or UEs, become intelligent and rich in terms of computing and communications capabilities, which intuitively enables big data analytics at the network edge. In this article, we propose to explore big data analytics to advance edge caching capability, which is considered as a promising approach to improve network efficiency and alleviate the high demand for the radio resou…
IEEE Access Special Section Editorial: Exploiting the Benefits of Interference in Wireless Networks: Energy Harvesting and Security
2018
Interference used to be viewed as a harmful factor in wireless networks, which can reduce the quality of information transmission. To combat against interference, many interference management techniques have emerged. Due to the latest research advances, interference (or noise) can also be exploited to offer some benefits to wireless networks. The first aspect is that interference in multi-user networks can be collected as a green power supply for the transceivers, known as wireless energy harvesting. Another application is that one can generate artificial noise to disrupt the adversarial eavesdropping, and guarantee the security of wireless networks. Therefore, conventional interference man…
A Double Auction Mechanism for Virtual Resource Allocation in SDN-based Cellular Network
2016
The explosively growing demands for mobile traffic service bring both challenges and opportunities to wireless net- works, among which, wireless network virtualization is proposed as the main evolution towards 5G. In this paper, we first propose a Software Defined Network (SDN) based wireless virtualization architecture for enabling multi-flow transmission in order to save capital expenses (CapEx) and operation expenses (OpEx) significantly with multiple Infrastructures Providers (InPs) and multiple Mobile Virtual Network Operators (MVNOs). We for- mulate the virtual resource allocation problem with diverse QoS requirements as a social welfare maximization problem with transaction cost. Due…
Sparsity-aware multiple relay selection in large multi-hop decode-and-forward relay networks
2016
In this paper, we propose and investigate two novel techniques to perform multiple relay selection in large multi-hop decode-and-forward relay networks. The two proposed techniques exploit sparse signal recovery theory to select multiple relays using the orthogonal matching pursuit algorithm and outperform state-of-the-art techniques in terms of outage probability and computation complexity. To reduce the amount of collected channel state information (CSI), we propose a limited-feedback scheme where only a limited number of relays feedback their CSI. Furthermore, a detailed performance-complexity tradeoff investigation is conducted for the different studied techniques and verified by Monte …
Energy Efficient Optimization for Wireless Virtualized Small Cell Networks With Large-Scale Multiple Antenna
2017
Wireless network virtualization is envisioned as a promising framework to provide efficient and customized services for next-generation wireless networks. In wireless virtualized networks (WVNs), limited radio resources are shared among different services providers for providing services to different users with heterogeneous demands. In this paper, we propose a resource allocation scheme for an orthogonal frequency division multiplexing-based WVN, where one small cell base station equipped with a large number of antennas serves the users with different service requirements. In particular, with the objective to obtain the energy efficiency in the uplink, a joint power, subcarrier, and antenn…