Search results for " networking"
showing 10 items of 1264 documents
Channel Occupancy-Based Dynamic Spectrum Leasing in Multichannel CRNs: Strategies and Performance Evaluation
2016
Spectrum leasing has been proposed as an effective approach for enabling more flexible spectrum utilization in CRNs. In CRNs, a primary network (PN) which consists of multiple primary users (PUs) can lease part of the licensed spectrum to secondary users (SUs) in exchange for operational benefits. The focus of this study is to investigate how and to what extent the PN allows spectrum leasing in CRNs, considering the QoS requirements of the PN and the secondary network (SN). Correspondingly, we propose two dynamic spectrum leasing strategies, which can improve the QoS performance of SUs while ensuring sufficient remuneration for PUs. In order to dynamically adjust the portion of leased bandw…
A Hybrid Algorithm Based on WiFi for Robust and Effective Indoor Positioning
2019
Indoor positioning based on the Wireless Fidelity (WiFi) protocol and the Pedestrian Dead Reckoning (PDR) approach is widely exploited because of the existing WiFi infrastructure in buildings and the advancement of built-in smartphone sensors. In this work, a hybrid algorithm that combines WiFi fingerprinting and PDR to both exploit their advantages as well as limiting the impact of their disadvantages is proposed. Specifically, to build a probability map from noisy Received Signal Strength (RSS), a Gaussian Process (GP) regression is deployed to estimate and construct the RSS fingerprints with incomplete data. Mean and variance of generated points are used to estimate WiFi fingerprinting p…
Experimental Characterization of Mobile Fading Channels Aiming the Design of Non-Wearable Fall Detection Radio Systems at 5.9 GHz
2016
One of the major concerns for the independent living of elderlies is a fall incident. To decrease human interaction errors and user privacy concerns of existing fall detection systems, a new generation of fall detection systems is emerging. The new trend is to design non-wearable devices that can monitor the physical activities of the home user using radio waves reflected off the body. This paper reports an in-home radio measurement campaign at 5.9 GHz, which has been conducted to study the impacts of different physical activities of the user, including fall incidents, on the channel transfer function (CTF) and the power delay profile (PDP) of indoor mobile radio channels. The home is equip…
Evaluating the user experience of omnidirectional VR walking simulators
2020
Abstract Omnidirectional treadmills (ODTs) have been traditionally proposed as a promising solution for users’ navigation in large-scale virtual environments. These mechanical devices enable users to perform locomotive motion with 360-deg freedom, while keeping their position fixed in the physical world. However, most locomotion approaches based on omnidirectional treadmills have presented either high acquisition or maintenance costs, being the capabilities of the general public, or a limited reliability. In this paper, we present a comparative usability and acceptance study with real users evaluating the two most common approaches for the development of this type of Virtual Reality (VR) wa…
A feasibility analysis on the use of ultrasonic multihop communications for E-health applications
2017
Rise in population aging as well as diffusion of chronic diseases and health consciousness require constant monitoring of health conditions but also lead to increasing costs for the governments. Body Area Networks represent the next frontier in health care and are envisaged as the natural choice to provide detailed and updated information on health status to prevent health risks and diseases. However if, on the one hand, a large research effort has been devoted so far to the investigation of BAN communications on and around the body, on the other hand intra-BAN communications are still a scarcely explored area because of the difficulties and risks in successfully propagating signals inside …
FALCON - joint fair airtime allocation and rate control for DASH video streaming in software defined wireless networks
2020
Software Defined Wireless Networks offer an opportunity to enhance the performance of specific services by applying centralized mechanisms which make use of a global view of the network resources. This paper presents FALCON, a novel solution that jointly optimizes fair airtime allocation and rate recommendations for Server and Network Assisted DASH video streaming, providing proportional fairness among the clients. Since this problem is NP-hard, FALCON introduces a novel heuristic algorithm that is proved to achieve almost optimal results in a practical amount of time. The performance of FALCON is evaluated when used in conjunction with three referent Adaptive Bit Rate strategies (PANDA, BO…
Evaluation of user experience goal fulfillment
2014
In this paper, the results of a user experience (UX) goal evaluation study are reported. The study was carried out as a part of a research and development project of a novel remote operator station (ROS) for container gantry crane operation in port yards. The objectives of the study were both to compare the UXs of two different user interface concepts and to give feedback on how well the UX goals experience of safe operation, sense of control, and feeling of presence are fulfilled with the developed ROS prototype. According to the results, the experience of safe operation and feeling of presence were not supported with the current version of the system. However, there was much better suppor…
Inference of Spatiotemporal Processes over Graphs via Kernel Kriged Kalman Filtering
2018
Inference of space-time signals evolving over graphs emerges naturally in a number of network science related applications. A frequently encountered challenge pertains to reconstructing such dynamic processes given their values over a subset of vertices and time instants. The present paper develops a graph-aware kernel-based kriged Kalman filtering approach that leverages the spatio-temporal dynamics to allow for efficient online reconstruction, while also coping with dynamically evolving network topologies. Laplacian kernels are employed to perform kriging over the graph when spatial second-order statistics are unknown, as is often the case. Numerical tests with synthetic and real data ill…
Blockchain based Inter-domain Latency Aware Routing Proposal in Software Defined Network
2018
Border gateway protocol (BGP) version 4 is routing current Internet for more than 20 years. BGP is the only protocol that has proven its routing capability of such size network with continually growing nature. Although BGP is scalable and network layer reachability information it lacks quality of service metrics like latency. BGP routing decision algorithm uses as-path length between autonomous systems (AS) as main factor for most of its best-path calculations. Because of more affordable peering architectures as-path length is generally decreasing in worldwide internet network resulting in less efficient routes for real-time internet protocol traffic. This study proposes future internet arc…
The Valencia Port Authority (VPA): environmental information in the annual report
2012
In recent years, most companies are participating in the disclosing of information on the impact of their potential activities on the environment. In 2002, Spain developed its legislation on environmental information in annual reports. The port industry has a potential environmental and economic impact. In this context, it is important to know how it disclosure environmental information in the annual reports. The case of study shows the disclosure information characteristics of Valencia Port Authority (VPA) and the relationships with the environment. The results concluded that VPA has adapted its information not only the standards but as a mean of legitimation.