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| 2. |
- Anderson, Ian, et al.
(författare)
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Shakra: tracking and sharing daily activity levels with unaugmented mobile phones
- 2007
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Ingår i: Mobile Networks and Applications. - : Springer Science and Business Media LLC. - 1383-469X .- 1572-8153. ; 12:2-3, s. 185-199
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Tidskriftsartikel (refereegranskat)abstract
- This paper explores the potential for use of an unaugmented commodity technology—the mobile phone— as a health promotion tool. We describe a prototype application that tracks the daily exercise activities of people, using an Artificial Neural Network (ANN) to analyse GSM cell signal strength and visibility to estimate a user’s movement. In a short-term study of the prototype that shared activity information amongst groups of friends, we found that awareness encouraged reflection on, and increased motivation for, daily activity. The study raised concerns regarding the reliability of ANN-facilitated activity detection in the ‘real world’. We describe some of the details of the pilot study and introduce a promising new approach to activity detection that has been developed in response to some of the issues raised by the pilot study, involving Hidden Markov Models (HMM), task modelling and unsupervised calibration. We conclude with our intended plans to develop the system further in order to carry out a longer-term clinical trial.
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| 3. |
- Battiti, R., et al.
(författare)
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Wireless LANs : From WarChalking to open access networks
- 2005
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Ingår i: Mobile Networks and Applications. - : Springer Science and Business Media LLC. - 1383-469X .- 1572-8153. ; 10:3, s. 275-287
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Tidskriftsartikel (refereegranskat)abstract
- This work discusses the evolution of W-LANs from their current status of wireless termination of LAN services to a possible global infrastructure where the access networks become open to multiple operators and a vehicle of a win-win scenario, where both users and operators benefit from the new network architecture. The idea of Open Access Networks (OANs) can go beyond wireless HotSpots and be generalized to a generic shared access infrastructure that fosters service operators competition and drastically reduces the cost of last mile coverage. The general concept of Open Access Networks is detailed, highlighting its difference with the more traditional model of vertical integration of the access network into the global service. About the OANs development, it is shown how to support the quick and smooth evolution of the infrastructure toward a widespread and reliable communication support. Business models are discussed by mentioning the different actors, the market organization and the different organization forms. The final part of the paper is devoted to technical challenges such as access control, security, privacy, roaming, resource exploitation and service differentiation. As an example of how to tackle these problems, we discuss a pricing technique devoted to resource management and billing support. In addition we present a simulation on how the OAN concept can speed-up the deployment of broadband access in a real case.
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| 4. |
- Chu, Thi My Chinh, et al.
(författare)
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Performance Assessment of OTFS Modulation in High Doppler Airborne Communication Networks
- 2022
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Ingår i: Mobile Networks and Applications. - : Springer. - 1383-469X .- 1572-8153. ; 27:4, s. 1746-1756
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Tidskriftsartikel (refereegranskat)abstract
- Emerging 5G and future 6G mobile networks are expected to cater for high mobility scenarios ranging from vehicle-to-vehicle communications to unmanned aerial vehicles and airborne platforms. Communications in this type of deployments suffer from severe Doppler shifts which require new modulation waveforms. Orthogonal time frequency space (OTFS) modulation has recently been proposed as a promising technology for coping with high Doppler channels. OTFS converts a time-varying fading channel into a time-independent channel in the two-dimensional delay-Doppler (DD) domain. The transmit symbols are multiplexed into a nearly constant channel with a complex channel gain in the DD domain. In this paper, we consider a high Doppler airborne communication network where relative mobile node speeds can be above 1200 m/s. The considered system represents a mobile ad-hoc network where the airborne mobile nodes can join or leave the network. Furthermore, each node is equipped with an antenna array that supports directed communication among mobile nodes. The Doppler shifts in this airborne communication network are in the order of 52-72 kHz and may potentially be even higher depending on the selected carrier frequency and the relative speed among the airborne platforms. As such, OTFS modulation is used in this work to efficiently compensate for the high Doppler shifts in the DD domain. In particular, a comprehensive performance assessment in terms of bit error rate (BER) is conducted to reveal the potential of OTFS modulation in dealing with such extreme transmission scenarios. The impact of physical layer parameters, number of delay-Doppler bins in the DD domain used for OTFS modulation, directed versus two-ray channels, and the combination of multiple-input multiple-output (MIMO) systems with OTFS modulation on the BER is assessed. It is shown that both OTFS modulation over a two-ray channel as well as MIMO-OTFS modulation provide a reliable airborne communication network with low BER. © 2022, The Author(s).
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| 5. |
- Cuce, Simon, et al.
(författare)
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Supporting multiple consistency models within a mobility enabled file system using a component based framework
- 2003
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Ingår i: Mobile Networks and Applications. - 1383-469X .- 1572-8153. ; 8:4, s. 317-326
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Tidskriftsartikel (refereegranskat)abstract
- Most existing Distributed File Systems (DFSs) implement a single consistency model to maintain one-copy equivalence. The functionality of that consistency model is based on a balance between environmental constraints and the targeted level of consistency. Such systems efficiently maintain consistency while the environmental capabilities remain constant, e.g., presuming uninterrupted connectivity. However, when these characteristics change, the inflexible nature of a single consistency model results in its inability to maintain an expected balance between consistency and constraints. This illustrated with existing implementations of DFSs. GLOMAR is a DFS middleware layer that allows application developers to map their specific consistency models to environmental constraints. As a result, multiple consistency models can be created, with each scoped for a particular application and environmental scenario. This paper outlines important aspects of GLOMAR, detailing its implementation and outlining a number of consistency models.
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| 7. |
- Feeney, Laura Marie
(författare)
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An energy-consumption model for performance analysis of routing protocols for mobile ad hoc networks
- 2001. - 1
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Ingår i: Mobile Networks and Applications. - 1383-469X .- 1572-8153. ; 6:3, s. 239-250
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Tidskriftsartikel (refereegranskat)abstract
- A mobile ad hoc network (or manet) is a group of mobile, wireless nodes which co-operatively form a network independent of any fixed infrastructure or centralised administration. In particular, a manet has no base stations: a node communicates directly with nodes within wireless range and indirectly with all other nodes using a dynamically computed, multi-hop route via the other nodes of the manet. Simulation and experimental results are combined to show that energy and bandwidth are substantially different metrics and that resource utilisation in manet routing protocols is not fully addressed by bandwidth-centric analysis. This report presents a model for evaluating the energy consumption behaviour of a mobile ad hoc network. The model was used to examine the energy consumption of two well-known manet routing protocols. Energy-aware performance analysis is shown to provide new insights into costly protocol behaviours and suggests opportunities for improvement at the protocol and link layers.
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| 8. |
- Forsström, Stefan, et al.
(författare)
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Continuously Changing Information on a Global Scale and its Impact for the Internet-of-Things
- 2014
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Ingår i: Mobile Networks and Applications. - : Springer Science and Business Media LLC. - 1383-469X .- 1572-8153. ; 19:1, s. 33-44
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Tidskriftsartikel (refereegranskat)abstract
- This article analyzes the challenges of supporting continual changes of context information in Internet-of-Things applications. These applications require a constant flow of continuously changing information from sensor based sources in order to ensure a high quality-of-experience. However, an uncontrolled flow between sources and sinks on a global scale wastes resources, such as computational power, communication bandwidth, and battery time. In response to these challenges we present a general approach which focuses on four layers where we provide a proposed solution to each layer. We have realized the general model into a proof-of-concept implementation running on devices with limited resources, where we can moderate the information exchange based on relevance and sought after quality-of-experience by the applications. In conclusion, we evaluate our solution and present a summary of our experiences regarding the impact of continuously changing information on the Internet-of-Things.
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| 9. |
- Jiang, Xiaolin, et al.
(författare)
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A Simplified Interference Model for Outdoor Millimeter-waveNetworks
- 2019
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Ingår i: Mobile Networks and Applications. - : Springer. - 1383-469X .- 1572-8153. ; 24:3, s. 983-990
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Tidskriftsartikel (refereegranskat)abstract
- Industry 4.0 is the emerging trend of the industrial automation. Millimeter-wave (mmWave) communication is a prominent technology for wireless networks to support the Industry 4.0 requirements. The availability of tractable accurate interference models would greatly facilitate performance analysis and protocol development for these networks. In this paper, we investigate the accuracy of an interference model that assumes impenetrable obstacles and neglects the sidelobes. We quantify the error of such a model in terms of statistical distribution of the signal to noise plus interference ratio and of the user rate for outdoor mmWave networks under different carrier frequencies and antenna array settings. The results show that assuming impenetrable obstacle comes at almost no accuracy penalty, and the accuracy of neglecting antenna sidelobes can be guaranteed with sufficiently large number of antenna elements. The comprehensive discussions of this paper provide useful insights for the performance analysis and protocol design of outdoor mmWave networks.
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| 10. |
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