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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications

作者： David M. Gutierrez-Estevez Berk Canberk Ian F. Akyildiz Broadband Wireless Network Laboratory School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta Georgia 30332 USA. Dept. of Computer Engineering Computer and Informatics Faculty Istanbul Technical University Ayazaga 34469 Istanbul-Turkey

ISBN: (纸本)9781467325660

Two-tier femtocell-based networks have been proposed as an economic solution to improve coverage and capacity in wireless cellular systems. Although widely studied in the literature, interference management in these networks remains as a technical challenge in need of effective solutions. In particular, the interference estimation is a relevant portion of the problem that enables correct operation of interference management schemes relying on this information. In this paper, a novel downlink cross-tier interference estimation approach is proposed based on spatio-temporal correlation techniques. An ordinary Kriging interpolator using Semivariogram Analysis is applied to the interfering signal followed by an autorregressive model. The signal estimation at the interfered users' location is exploited at the radio resource manager of the femtocell or macrocell base station by formulating a resource allocation problem that is solved by means of a heuristic algorithm. A practical procedure implementing this scheme in the network is also proposed. Numerical results show how performance of crosstier interference management approaches can be optimized by implementing this idea.

关键词： Spatio-Temporal correlation techniques Two-tier

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Optimizing the combination of MBSFN and PTM transmissions in LTE systems

Optimizing the combination of MBSFN and PTM transmissions in...

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10th Annual Wireless Telecommunications Symposium, WTS 2011

作者： Alexiou, Antonios Bouras, Christos Kokkinos, Vasileios Papazois, Andreas Tseliou, Georgia Research Academic Computer Technology Institute Patras Greece Computer Engineering and Informatics Dept. Univ. of Patras Greece

ISBN: (纸本)9781457701627

The 3rd Generation Partnership Project (3GPP) has introduced the evolved Multimedia Broadcast/Multicast Service (e-MBMS) feature for cellular systems as an evolution to the existing MBMS service. To support e-MBMS in Long Term Evolution (LTE) systems, 3GPP recommends the use of Point-to-Multipoint (PTM) transmissions and MBMS over a Single Frequency Network (MBSFN). MBSFN is a new feature where a time-synchronized common waveform is transmitted from multiple cells. In this paper we investigate the provision of MBMS service over a combination of MBSFN and PTM transmission methods. A cost analysis of the MBMS service is presented based on the transmission cost over all the interfaces and nodes of the LTE architecture. We evaluate the performance of this transmission scheme from telecommunication cost perspective and we compare it with other transmission schemes. The performance evaluation has been performed with the aid of a new simulation tool that estimates the cost for the MBMS provision under different network topologies, MBSFN deployments and user distributions. © 2011 IEEE.

关键词： Network topology

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GRAL: A grouping algorithm to optimize application placement in wireless embedded systems

GRAL: A grouping algorithm to optimize application placement...

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25th IEEE International Parallel and Distributed Processing Symposium, IPDPS 2011

作者： Tziritas, Nikos Loukopoulos, Thanasis Lalis, Spyros Lampsas, Petros Center for Research and Technology Thessaly Volos Greece Dept. of Computer and Communication Engineering Univ. of Thessaly Volos Greece Dept. of Informatics and Computer Technology TEI of Lamia Lamia Greece

ISBN: (纸本)9780769543857

Recent embedded middleware initiatives enable the structuring of an application as a set of collaborating agents deployed in the various sensing/actuating entities of the system. Of particular importance is the incurred cost due to agent communication which in terms depends on agent positions in the system. In this paper we present GRAL a grouping algorithm that migrates groups of agents with the aim of minimizing communication. The algorithm works in a distributed fashion based on knowledge available locally at each node and can be used both for one-shot initial application deployment and for the continuous updating of agent placement. Through simulation experiments under various scenarios we evaluate the algorithm, comparing the solution quality reached against.the optimal obtained from exhaustive search. © 2011 IEEE.

关键词： Embedded systems

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Power management for SVC video over wireless networks

Power management for SVC video over wireless networks

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6th International Conference on Broadband and Wireless Computing, Communication and Applications, BWCCA-2011

作者： Bouras, C. Charalambides, S. Stamos, K. Stroumpis, S. Zaoudis, G. Computer Technology Institute and Press Diophantus Patra Greece Computer Engineering and Informatics Dept. University of Patras Greece Technological Educational Institute of Patras Greece

ISBN: (纸本)9780769545325

The main idea of this paper is to study how the emerging H.264 SVC standard can be utilized for more efficient power management in wireless video transmissions. Our proposal uses a cross-layer approach which adapts the power transmission level of the sender according to the SVC information regarding the priority of the SVC NAL frame. Our aim is to improve transmission statistics, and therefore user experience, without unnecessary power consumption. We use extensive experimentation on the ns2 network simulator, which we have specifically modified for this purpose, in order to verify this approach. © 2011 IEEE.

关键词： Power management

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Allothetic and idiothetic sensor fusion in rat-inspired robot localization

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Proceedings of SPIE - The International Society for Optical engineering 2012年 8407卷

作者： Weitzenfeld, Alfredo Fellous, Jean-Marc Barrera, Alejandra Tejera, Gonzalo Div. of Information Technology University of South Florida Polytechnic 3433 Winter Lake Rd Lakeland FL 33803 United States Dept. of Psychology and Applied Mathematics University of Arizona 1503 E University Blvd. Tucson AZ 85721 United States Dept. of Computer Engineering Instituto Tecnológico Autónomo de México Rio Hondo #1 Mexico DF 01080 Mexico Inst. of Comp. Julio Herrera y Reissig 565 Universidad de la República Montevideo 11300 Uruguay

ISBN: (纸本)9780819490858

We describe a spatial cognition model based on the rat's brain neurophysiology as a basis for new robotic navigation architectures. The model integrates allothetic (external visual landmarks) and idiothetic (internal kinesthetic information) cues to train either rat or robot to learn a path enabling it to reach a goal from multiple starting positions. It stands in contrast to most robotic architectures based on SLAM, where a map of the environment is built to provide probabilistic localization information computed from robot odometry and landmark perception. Allothetic cues suffer in general from perceptual ambiguity when trying to distinguish between places with equivalent visual patterns, while idiothetic cues suffer from imprecise motions and limited memory recalls. We experiment with both types of cues in different maze configurations by training rats and robots to find the goal starting from a fixed location, and then testing them to reach the same target from new starting locations. We show that the robot, after having pre-explored a maze, can find a goal with improved efficiency, and is able to (1) learn the correct route to reach the goal, (2) recognize places already visited, and (3) exploit allothetic and idiothetic cues to improve on its performance. We finally contrast our biologically-inspired approach to more traditional robotic approaches and discuss current work in progress. © 2012 SPIE.

关键词： Robots

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Cyclic steady state refinement

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作者： Bocewicz, Grzegorz Wójcik, Robert Banaszak, Zbigniew A. Dept. of Computer Science and Management Koszalin University of Technology Koszalin Poland Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wroclaw Poland Faculty of Management Dept. of Business Informatics Warsaw University of Technology Warsaw Poland

ISBN: (纸本)9783642199332

The paper presents a new modeling framework enabling to evaluate the cyclic steady state of a given system of concurrently flowing cyclic processes (SCCP) on the base of the assumed topology of transportation routes, dispatching rules employed, resources and operation times as well as an initial processes allocation. The objective is to provide the rules useful in the course of routing and scheduling executed in SCCP where local cyclic processes interact on the base of a mutual exclusion protocol. © 2011 Springer-Verlag Berlin Heidelberg.

关键词： Transportation routes

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Nonparametric density estimation on a graph: Learning framework, fast approximation and application in image segmentation

Nonparametric density estimation on a graph: Learning framew...

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作者： Yu, Zhiding Au, Oscar C. Tang, Ketan Xu, Chunjing Dept. of Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong Shenzhen Inst. of dvanced Technology Chinese Academy of Sciences China

ISBN: (纸本)9781457703942

We present a novel framework for tree-structure embedded density estimation and its fast approximation for mode seeking. The proposed method could find diverse applications in computer vision and feature space analysis. Given any undirected, connected and weighted graph, the density function is defined as a joint representation of the feature space and the distance domain on the graph's spanning tree. Since the distance domain of a tree is a constrained one, mode seeking can not be directly achieved by traditional mean shift in both domain. we address this problem by introducing node shifting with force competition and its fast approximation. Our work is closely related to the previous literature of nonparametric methods. One shall see, however, that the new formulation of this problem can lead to many advantages and new characteristics in its application, as will be illustrated later in this paper. © 2011 IEEE.

关键词： Image segmentation

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Quantization-and prediction-based image authentication and recovery

Quantization-and prediction-based image authentication and r...

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5th International Conference on Genetic and Evolutionary Computing, ICGEC2011

作者： Wu, Wen-Chuan Hsieh, Yi-Pei Dept. of Computer Science and Information Engineering Aletheia University Taipei 25103 Taiwan Dept. of Information Engineering and Informatics Tzu Chi College of Technology Hualien 970 Taiwan

ISBN: (纸本)9780769544496

This paper proposed an image authentication technique based on a data compression and prediction mechanism in order to verify if a digital image was tampered with over the network. For image blocks, first is to produce special verification codes, and next, these codes and other information related to data recovery will be embedded into the image. When someone receives a suspicious image, he/she can check the integrity of embedded verification codes to judge whether the image was tampered with or not. Further, the recovery information extracted from images can be used to restore the tampered area. Experimental results showed the proposed scheme not only marks those tampered area effectively, but is able to recover them back to initial as similar as possible in order to reduce retransmitting probability and save network bandwidth. © 2011 IEEE.

关键词： Forecasting

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Cross-layer mechanism for efficient video transmission over mobile ad hoc networks

Cross-layer mechanism for efficient video transmission over ...

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2011 3rd International Workshop on Cross Layer Design, IWCLD 2011

作者： Adam, G. Bouras, C. Gkamas, A. Kapoulas, V. Kioumourtzis, G. Tavoularis, N. Computer Technology Institute and Press Diophantus Patras Greece Computer Engineering and Informatics Dept. Univ. of Patras Greece University Ecclesiastical Academy of Vella Ioannina Greece

ISBN: (纸本)9781457715686

Mobile ad hoc networks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. However, MANETs do not seem to effectively support multimedia applications and especially video transmission. This paper presents a cross-layer mechanism for efficient video transmission over this type of networks. The proposed mechanism consists of a priority-scheduling algorithm, at the network layer, and the use of the IEEE 802.11e standard at the MAC layer. The priority-scheduling algorithm takes into account the frame type of the MPEG-4 video file in order to provide different priorities to the most important video packets. At the MAC layer, the IEEE 802.11e protocol assigns the highest priority to video applications to reduce delay and packets losses due to other competing traffic. This design is easily implemented in any ad hoc wireless network as an extension on the AODV MANET routing protocol. Simulation results conducted with the network simulator ns-2 show the advantages of the proposed design. © 2011 IEEE.

关键词： Scheduling algorithms

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Performance evaluation of routing protocols for multimedia transmission over mobile ad hoc networks

Performance evaluation of routing protocols for multimedia t...

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2011 4th Joint IFIP Wireless and Mobile Networking Conference, WMNC 2011

作者： Adam, George Bouras, Christos Gkamas, Apostolos Kapoulas, Vaggelis Kioumourtzis, Georgios Tavoularis, Nikos Computer Technology Institute and Press Patras Greece Computer Engineering and Informatics Dept. Univ. of Patras Patras Greece University Ecclesiastical Academy of Vella Ioannina Greece

ISBN: (纸本)9781457711930

Mobile ad hoc networks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. The integration of mobile ad hoc devices inside vehicles has led to another type of networks, called Vehicular Ad hoc Networks (VANETs) which are also becoming important. These networks require specialized routing protocols due to their ad hoc nature. The performance of these protocols has been tested for the case of general traffic but not in respect with to multimedia traffic and especially video transmission. In this paper we conduct a number of simulations in order to evaluate the performance of three of the most popular routing protocols for MANETs and VANETs, namely AODV, DSR and OLSR, for different number of simultaneous video transmissions. We use the packet delivery ratio, the end-to-end delay, the packet delay variation (jitter) and the routing overhead as evaluation metrics. The results indicate that the DSR protocol outperforms AODV and OLSR in terms of end-to-end delay and packet delay variation and seems to be the most efficient routing protocol when multimedia traffic and especially video traffic is considered. © 2011 IEEE.

关键词： Routing protocols

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