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The effects of the number of neighbors in multihop wireless networks
No full textPurpose – In multihop wireless networks, the number of neighbors has an important role in the network performance since links are dynamically formed between a node and its neighbors. This paper aims to investigate this issue.
Design/methodology/approach – The paper quantitatively studies the effects of the average number of neighbors in multihop wireless networks on the network connectivity, the number of hops needed to traverse a certain distance, which can be used to determine the hop diameter of a network, and the total energy consumed by packet transmission, which can be used to choose an optimum average number of neighbors that minimizes the energy consumption. This paper also presents an analysis of the energy consumption that can be applied to a wide range of access protocols and show the effect of a variety of factors.
Findings – Results show that the minimum average number of neighbors to guarantee the overall network connectivity depends on the size of a network coverage. There is a sharp knee in the network connectivity with decrease of the average number of neighbors, N. If the distance between a source and destination, d, is known, the number of hops needed to reach the destination is usually between d/R~2d/R, where R is the transmission range. A larger average number of neighbors N leads to a smaller number of hops to traverse a certain distance, which in turn results in a smaller traffic load caused by relaying packets. However, a bigger N also causes more collisions when a contention medium access scheme is used, which leads to more energy consumed by packet transmission. The results show that the optimum N which minimizes the energy is obtained by balancing several factors affecting the energy.
Originality/value – The paper provides a useful study on the effects of the number of neighbors in multihop wireless networks.TRUEpu
FloorNet: Deployment and Evaluation of a Multihop Wireless 802.11 Testbed
Get PDFA lot of attention has been given to multihop wireless networks lately, but further research—in particular, through
experimentation—is needed. This attention has motivated an increase in the number of 802.11-based deployments, both indoor and outdoor. These testbeds, which require a significant amount of resources during both deployment and maintenance, are used to run measurements in order to analyze and understand the limitation and differences between analytical or simulation-based figures and the results from real-life experimentation. This paper makes two major contributions: (i) first, we describe a novel
wireless multihop testbed, which we name FloorNet, that is deployed and operated under the false floor of a lab in our Computer Science building. This false floor provides a strong physical protection that prevents disconnections or misplacements, as well as radio shielding (to some extent) thanks to the false floor panels—this later feature is assessed through experimentation; (ii) second, by running exhaustive and controlled experiments we are able to analyze the performance limits of commercial off-theshelf
hardware, as well as to derive practical design criteria for the deployment and configuration of mesh networks.
These results both provide valuable insights of wireless multihop performance and prove that FloorNet constitutes a valuable asset to research on wireless mesh networks.TRUEpu
Scalable Max-Min Fairness in Wireless Ad Hoc Networks
No full textMacro Model, Max-Min Fairness, Scalability, Quality of Service.Our previous work proposes a macro model to perform flow and access control in wireless ad hoc networks. In this paper, we demonstrate specifically how to apply the model to achieve max-min fair rate allocation. Our proposed scheme is simple and scalable when comparing to other techniques in the literature. Moreover, it has the ability to provide stability in mobile environment. Simulation results show that our new method provides a good max-min fair flow assignment, and with that assignment, quality of service guarantees can be achieved for real-time applications.TRUEpu
Interacting with Digital Signage Using Hand Gestures
Get PDFProceedings of the 6th International Conference, ICIAR 2009, Halifax, Canada, July 6-8, 2009, published by "Lecture Notes in Computer Science" journal.
DOI: 10.1007/978-3-642-02611-9_35
Print ISBN: 978-3-642-02610-2
Online ISBN: 978-3-642-02611-9
Series Title
Series Volume: 5627Digital signage is a very attractive medium for advertisement and general communications in public open spaces. In order to add interaction capabilities to digital signage displays, special considerations must be taken. For example, the signs’ environment and placement might prevent direct access to conventional means of interaction, such
as using a keyboard or a touch-sensitive screen. This paper describes a vision-based gesture recognition approach to interact with digital signage systems and discusses the issues faced by such systems. Using Haar-like features and the AdaBoosting algorithm, a set of hand gestures can be
recognized in real-time and converted to gesture commands to control and manipulate the digital signage display. A demonstrative application using this gesture recognition interface is also depicted.TRUEpu
Research on Future Media Internet
Get PDFCreated by “Future Media Internet Task Force”
Coordinated by five FP7 Networks of Excellence supported by
the Networked Media Unit of the DG Information Society and
Media of the European CommissionNetworked Media Unit, DG Information Society and Media of the European CommissionInformation Society and MediaEuropean Commissionpu
fP2P–HN: A P2P-based route optimization architecture for mobile IP-based community networks
Get PDFWireless technologies are rapidly evolving and the users are demanding the possibility of changing their point of attachment to the Internet (i.e. Access Routers) without breaking the IP communications. This can be achieved by using Mobile IP or NEMO. However, mobile clients must forward their data packets through its Home Agent (HA) to communicate with its peers. This sub-optimal route (lack of route optimization) considerably reduces the communications performance, increases the delay and the infrastructure load. In this paper, we present fP2P–HN, a Peer-to-Peer-based architecture that allows deploying several
HAs throughout the Internet. With this architecture, a Mobile Node (MN) or a Mobile Community Network (i.e. a NEMO) can select a closer HA to its topological position in order to reduce the delay of the paths towards its peers. fP2P–HN uses a Peer-to-Peer network to signal the location of the different HAs. Additionally, it uses flexible HAs that significantly reduce the amount of packets processed by the HA itself. The main advantages of the fP2P–HN over the existing ones are that it is scalable, it reduces the communications delay and the load at the HAs. Since one of the main concerns in mobility is security, our solution provides authentication between the HAs and the MNs. We evaluate the performance of the fP2P–HN by simulation. Our results show that the fP2P–HN is scalable since the amount
of signalling messages per HA does not increase, even if the number of deployed HAs increases. We also show that the average reduction of the communication’s delay compared
to Mobile IP/NEMO is 23% (with a minimum deployment) and the reduction of the load at the HA is at least 54%.TRUEpu
Relevant Feature Selection and Generation in High Dimensional Haptic-based Biometric Data
No full textIn this paper, a study is conducted in order to
explore the use of genetic programming, in particular gene
expression programming (GEP), in finding analytic functions
that can behave as classifiers in high-dimensional haptic feature spaces. More importantly, the determined explicit functions are used in discovering minimal knowledge-preserving subsets of features from very high dimensional haptic datasets, thus acting as general dimensionality reducers. This approach is applied to the haptic-based biometrics problem; namely, in user identity verification. GEP models are initially generated using the original haptic biometric datatset, which is imbalanced
in terms of the number of representative instances of each
class. This procedure was repeated while considering an undersampled (balanced) version of the datasets. The results demonstrated that for all datasets, whether imbalanced or undersampled, a certain number (on average) of perfect classification models were determined. In addition, using GEP, great feature reduction was achieved as the generated analytic functions (classifiers) exploited only a small fraction of the available features.TRUEpu
Enabling Layered Video Coding for IMS-Based IPTV Home Services
Get PDFNowadays IPTV services are gaining attention from both providers and end users. There is a large effort toward the integration of these services into emerging nextgeneration
network architectures. In particular, one of the most relevant solutions is being proposed by ETSI-TISPAN and is based on the IP multimedia subsystem. This article focuses on introducing layered video coding into TISPAN IMS-based IPTV architecture, allowing cost-effective efficient solutions both for residential users and providers (e.g., flexible support of heterogeneous devices, live mosaics, adaptive video quality based on device and/or network capabilities). The advantages of using layered video coding in the TISPAN IPTV solution are analyzed and illustrated with a set of use cases. Furthermore, this solution has been integrated into a multimedia testbed in order to validate the presented proposal.TRUEpu
Energy Efficient Management of two Cellular Access Networks
Get PDFIn this paper we evaluate the energy saving that can be achieved with the energy-aware cooperative management of the cellular access networks of two operators offering service over the same area. We evaluate the amount of energy that can be saved by using both networks in high traffic conditions, but switching off one of the two
during the periods when traffic is so low that the desired quality of service can be obtained with just one network. When one of the two networks is off, its customers are allowed to roam over the one that is on. Several alternatives are studied, as regards the switch-off pattern:
the one that balances the switch-off frequencies, the one that balances roaming costs, the one that balances energy savings, and the one that maximizes the amount of saved energy. Our results indicate that a huge amount of energy can be saved, and suggest that, to reduce energy consumption, new cooperative attitudes of the operators should be encouraged with appropriate incentives, or
even enforced by regulation authorities.TRUEpu