Search results for "Electron"

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…

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…

Underwater Multirobot Cooperative Intervention MAC Protocol

2020

This work introduces a Medium Access Control (MAC) protocol designed to allow a group of underwater robots that share a wireless communication channel to effectively communicate with each other. The goal of the Underwater Multirobot Cooperative Intervention MAC (UMCI-MAC) protocol presented in this work is to minimize the end to end delay and the jitter. The access to the medium in UMCI-MAC follows a Time Division Multiple Access (TDMA) strategy which is arbitrated by a master, which also has the capability to prioritize the transmission of some nodes over the rest of the network. Two experiments have been carried out with a team of four Autonomous Underwater Vehicles (AUV) in order to comp…

Resource Allocation and Computation Offloading for Wireless Powered Mobile Edge Computing

2022

In this paper, we investigate a resource allocation and computation offloading problem in a heterogeneous mobile edge computing (MEC) system. In the considered system, a wireless power transfer (WPT) base station (BS) with an MEC sever is able to deliver wireless energy to the mobile devices (MDs), and the MDs can utilize the harvested energy for local computing or task offloading to the WPT BS or a Macro BS (MBS) with a stronger computing server. In particular, we consider that the WPT BS can utilize full- or half-duplex wireless energy transmission mode to empower the MDs. The aim of this work focuses on optimizing the offloading decision, full/half-duplex energy harvesting mode and energ…

Investigating document availability : ethnographic study on a technical specification

1999

The Large Observatory For x-ray Timing

2014

The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final down-selection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supra-nuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m 2 effective area, 2-30 keV, 240 eV spectral resolution, 1 deg collimated field of view) and a WideFi…