Search results for "NETWORKING"
showing 10 items of 1776 documents
Accuracy of stereotactic coordinate transformation using a localisation frame and computed tomographic imaging
1999
The accuracy of coordinate transformation from a CT image to a stereotactic frame was investigated for stereotactic systems using a localisation frame and matrix-based coordinate transformation. The main source of error influencing calculation was input data, due to inaccurate calculation of the centres of the rods of the localisation frame in the CT image, and the propagation of this input error during subsequent matrix calculation. Systemic errors during matrix calculation do not exist, and rounding off errors were of subordinate importance compared to the input data error. The influence of input data error on coordinate transformation was studied by geometric methods, computer simulation…
Genres of participation in social networking systems: A study of the 2009 Norwegian parliamentary election
2010
Published version of a chapter in the book: Electronic Participation. Also available at http://dx.doi.org/10.1007/978-3-642-15158-3_9 In the Norwegian context, eParticipation in the form of online campaigning has been on the agenda since 2001. After Obama’s successful presidential campaign in 2008, expectations about the use of SNS in the Norwegian parliamentary election were high. This study explores genres of participation in the early stages of the 2009 Norwegian parliamentary election campaign. The main finding is that the political parties have seen the need for a presence in SNS’, and that a genre repertoire for political communication through SNS is beginning to evolve. However, ther…
Stochastic Graph Filtering Under Asymmetric Links in Wireless Sensor Networks
2018
Wireless sensor networks (WSN s) are often characterized by random and asymmetric packet losses due to the wireless medium, leading to network topologies that can be modeled as random, time-varying and directed graphs. Most of existing works related to graph filtering in the context of WSNs assume that the probability of delivering an information from one node to a neighbor node is the same as in the reverse direction. This assumption is not realistic due to the typical link asymmetry in WSNs caused by interferences and background noise. In this work, we analyze the problem of applying stochastic graph filtering over random time-varying asymmetric network topologies. We show that it is poss…
Channel Modeling and System Concepts for Future Terahertz Communications: Getting Ready for Advances Beyond 5G
2020
Future terahertz (THz) communications will utilize the frequency spectrum around 300 GHz. This technology provides a promising solution for future high-data-rate communications due to the high available bandwidth. However, the unfavorable channel characteristics are a major barrier for the realization of THz communications. To address the challenges caused by the unfavorable propagation conditions, the world?s first THz communication standard includes a channel-modeling document (CMD).
A User-Centered Approach to Digital Household Risk Management
2020
Internet of Things (IoT) is expected to become as common as electricity (OECD 2016) and there is a high probability for connected homes to become central parts of critical societal. IoT technologies might access, manage and record sensitive data about citizens and, as they become more and more pervasive, unintended data breaches reports increase every week. However, most of the tools designed to protect users’ privacy and personal data on IoT devices fail to contemplate the experience of persons with disabilities, elderly and other vulnerable categories of people. As a consequence, they are forced to rely on the help of family members or other related persons with technical skills, as frequ…
1 Hop or 2 hops: Topology analysis in Body Area Network
2014
Wireless Body Area Networks (WBANs) have recently received much attention due to the possibility to be used in healthcare applications. For these applications, link reliability and energy efficiency are critical issues, as in many cases, information carried can be vital for the patient and batteries cannot be easily replaced. The wireless on-body channel experiences significant temporal variation due to body movements and the use of relays is sometimes necessary in order to guarantee reliability or improve lifetime. In this paper, an experimental evaluation is used to give a better understanding about reliability, energy consumption and lifetime in a single hop or a two hops communication. …
Proactive Future Internet: Smart Semantic Middleware for Overlay Architecture
2009
Some initiatives towards Future Internet, e.g., GENI, DARPA's Active Networks, argue the need for programmability of the network components. Some other initiatives extend this with argumentation for declarative networking, where the behavior of a network component is specified using some high-level declarative language, with a software-based engine implementing the behavior based on that specification. Our Proactive Future Internet (PROFI) vision follows these initiatives targeting also the following two problems: interoperability of the network elements programmed by different organizations, and the need for flexible cooperation among network elements, including coordination, conflict reso…
Performance evaluation of a measurement-based algorithm for distributed admission control in a DiffServ framework
2002
Distributed Admission Control in IP DiffServ environments is an emerging and promising research area. Distributed admission control solutions share the idea that no coordination among network routers (i.e. explicit signaling) is necessary, when the decision whether to admit or reject a new offered flow is pushed to the edge of the IP network. Proposed solutions differ in the degree of complexity required in internal network routers, and result in a different robustness and effectiveness in controlling the accepted traffic. This paper builds on a recently proposed distributed admission control solution, called GRIP (Gauge&Gate Reservation with Independent Probing), designed to integrate the …
A Multi-Relay Cooperative Automatic Repeat Request Protocol in Wireless Networks
2010
This paper proposes a Multi-relay Cooperative Automatic Repeat ReQuest protocol (MC-ARQ) for IEEE 802.11 based wireless networks. The proposed distributed relay selection scheme not only selects the best relays but also solves the collision problem among multiple contending relays, by sorting the relays in the network according to their instantaneous channel quality with the destination node. No prior information or explicit signaling among relay nodes is required. Both analytical and simulation results show that significant benefits can be achieved with the MC-ARQ protocol, compared with both the recently proposed PRCSMA scheme and the original non-cooperative DCF scheme.
Low-Cost Sensor Based on SDR Platforms for TETRA Signals Monitoring
2021
The paper presents the design and implementation of an electromagnetic field monitoring sensor for the measurement of the Terrestrial Truncked Radio (TETRA) signals using low-cost software defined radio (SDR) platforms. The sensor includes: an SDR platform, a Global Positioning System (GPS) module and a hardware control module. Several SDR platforms having different resolutions of the analog–digital converters were tested in the first phase. The control module was implemented in two variants: a fixed one, using a laptop, and a mobile one, using a Raspberry Pi. The tests demonstrate the following achieved performances: instantaneous acquisition band of 5.12 MHz