Search results for "Network"
showing 10 items of 7718 documents
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…
New client puzzle approach for DoS resistance in ad hoc Networks
2010
In this paper we propose a new client puzzle approach to prevent Denial of Service (DoS) attacks in ad hoc networks. Each node in the network first solves a computational problem and with the solution has to create and solve a client puzzle. By combining computational problems with puzzles, we improve the efficiency and latency of the communicating nodes and resistance in DoS attacks. Experimental results show the effectiveness of our approach.
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. …
Morphological similarities between DBM and an economic geography model of city growth
2009
International audience; An urban microeconomic model of households evolving in a 2Dcellular automata allows to simulate the growth of a metropolitan area whereland is devoted to housing, road network and agricultural/green areas. Thissystem is self-organised: based on individualistic decisions of economic agentswho compete on the land market, the model generates a metropolitan area withhouses, roads, and agriculture. Several simulation are performed. The resultsshow strong similarities with physical Dieletric breackdown models (DBM). Inparticular, phase transitions in the urban morphology occur when a controlparameter reaches critical values. Population density in our model and theelectric …
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.
The Role of the Integrated Public Transport Network for Reducing the Congestion in the City of Palermo
2019
The railway link of Palermo is part of the Palermo – Trapani railway line and it is located in the urban site of Palermo. Works funded by the European Union have been started in 2008 for developing a metropolitan service through the improvement of the infrastructure and of the transport service characteristics. The aim of the paper is the analysis of the capacity of the railway infrastructure in terms of frequency and integration with the public transport service of Palermo. Using the Origin-Destination matrix of the Urban Transport Plan of Palermo, the competition between the private car mode and the public transport mode has been simulated, taking into account the improving of the railway…