198 research outputs found
WING/WORLD: An Open Experimental Toolkit for the Design and Deployment of IEEE 802.11-Based Wireless Mesh Networks Testbeds
Wireless Mesh Networks represent an interesting instance of light-infrastructure wireless networks. Due to their flexibility and resiliency to network failures, wireless mesh networks are particularly suitable for incremental and rapid deployments of wireless access networks in both metropolitan and rural areas. This paper illustrates the design and development of an open toolkit aimed at supporting the design of different solutions for wireless mesh networking by enabling real evaluation, validation, and demonstration. The resulting testbed is based on off-the-shelf hardware components and open-source software and is focused on IEEE 802.11 commodity devices. The software toolkit is based on an "open" philosophy and aims at providing the scientific community with a tool for effective and reproducible performance analysis of WMNs. The paper describes the architecture of the toolkit, and its core functionalities, as well as its potential evolutions
Cognitive conflict is an example of action-grounded cognition.
The aim of the present work was to show that cognitive conflict, an issue that has been widely studied within the boundaries of the classical cognitive approach, is a clear example of higher order cognition tied to perception and action. Examples of how the cognitive conflict arising from spatial correspondence tasks is highly grounded in body attributes and in environmental/situational factors are provided. Spatial performance is strongly modulated by handedness, prior experience and by social factors. In addition, in two experiments empirical findings are reported showing that the spatial correspondence effect is a function of the location of the dynamic event even when target location is in the opposite position. These results point to the notion that spatial performance is refractory from the intervention of higher order cognition
Design and experimental validation of a software-defined radio access network testbed with slicing support
Network slicing is a fundamental feature of 5G systems to partition a single network into a number of segregated logical networks, each optimized for a particular type of service or dedicated to a particular customer or application. The realization of network slicing is particularly challenging in the Radio Access Network (RAN) part, where multiple slices can be multiplexed over the same radio channel and Radio Resource Management (RRM) functions shall be used to split the cell radio resources and achieve the expected behaviour per slice. In this context, this paper describes the key design and implementation aspects of a Software-Defined RAN (SD-RAN) experimental testbed with slicing support. The testbed has been designed consistently with the slicing capabilities and related management framework established by 3GPP in Release 15. The testbed is used to demonstrate the provisioning of RAN slices (e.g., preparation, commissioning, and activation phases) and the operation of the implemented RRM functionality for slice-aware admission control and scheduling.Peer ReviewedPostprint (published version
ONIX: Open Radio Network Information eXchange
While video-on-demand still takes up the lion's share of Internet traffic, we are witnessing a significant increase in the adoption of mobile applications defined by tight bit rate and latency requirements (e.g., augmented/virtual reality). Supporting such applications over a mobile network is very challenging due to the unsteady nature of the network and the long distance between the users and the application back-end, which usually sits in the cloud. To address these and other challenges, like security, reliability, and scalability, a new paradigm termed multi-access edge computing (MEC) has emerged. MEC places computational resources closer to the end users, thus reducing the overall end-to-end latency and the utilization of the network backhaul. However, to adapt to the volatile nature of a mobile network, MEC applications need real-time information about the status of the radio channel. The ETSI-defined radio network information service (RNIS) is in charge of providing MEC applications with up-to-date information about the radio network. In this article, we first discuss three use cases that can benefit from the RNIS (collision avoidance, media streaming, and Industrial Internet of Things). Then we analyze the requirements and challenges underpinning the design of a scalable RNIS platform, and report on a prototype implementation and its evaluation. Finally, we provide a roadmap of future research challenges
JANUS: A Framework for Distributed Management of Wireless Mesh Networks
Abstract — Wireless Mesh Networks (WMNs) are emerging as a potentially attractive access architecture for metropolitan-scale networks. While research on WMNs has been up to a large extent confined to the study of efficient routing protocols, there is a clear need to envision new network management tools, able to sufficiently exploit the peculiarities of WMNs. In particular, a new generation of middleware tools for network monitoring and profiling must be introduced in order to speed up development and testing of novel protocol architectures. Currently, manage-ment functionalities are developed using conventional central-ized approaches. The distributed and self-organizing nature of WMNs suggest a transition from network monitoring to network sensing. In this work, we propose JANUS, a novel framework for distributed monitoring of WMNs. We describe the JANUS architecture, present a possible implementation based on open-source software and report some experimental measurements carried out on a small-scale testbed. Index Terms — wireless mesh networks, network management, distributed hash table, overlay networks, publish-subscribe sys-tems I
Clinical evaluation of techniques used in the surgical treatment of progressive hemifacial atrophy
We critically review 13 patients with progressive hemifacial atrophy treated with three basic surgical procedures (free flap transplantation, alloplastic implants, micro-fat injections ‘lipofilling’) and further ancillary techniques. In spite of the satisfactory results achieved with the procedures, with the exception of alloplasts, we feel that lipofilling may be considered an interesting solution for soft tissue augmentation of the face especially for moderate adipose defects, due to its repeatability, no donor site morbidity, no complications at the recipient site such as lesions resulting from dissection, bleeding, necrosis, etc. This technique can be performed in a day-hospital with short surgery time, at low cost and without a highly skilled team. For severe grades of adipose atrophy, because of the low blood supply to these tissues which interferes with take of any type of autograft, we think that free flaps actually represent one of the best solutions for soft tissue augmentation
Programming Abstractions for Software–Defined Wireless Networks
Software-Defined Networking (SDN) has received, in the last years, significant interest from the academic and the industrial communities alike. The decoupled control and data planes found in an SDN allows for logically centralized intelligence in the control plane and generalized network hardware in the data plane. Although the current SDN ecosystem provides a rich support for wired packet-switched networks, the same cannot be said for wireless networks where specific radio data-plane abstractions, controllers, and programming primitives are still yet to be established. In this work, we present a set of programming abstractions modeling the fundamental aspects of a wireless network, namely state management, resource provisioning, network monitoring, and network reconfiguration. The proposed abstractions hide away the implementation details of the underlying wireless technology providing programmers with expressive tools to control the state of the network. We also present a Software-Defined Radio Access Network Controller for Enterprise WLANs and a Python--based Software Development Kit implementing the proposed abstractions. Finally, we experimentally evaluate the usefulness, efficiency and flexibility of the platform over a real 802.11-based WLAN
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