ppxscal/embedding_network huggingface dataset:
Throughput enhancement in wireless slotted ALOHA with space-time coding and collision processing
Authors: Nejah Missaoui, Inès Kammoun, Mohamed Siala
Venue: Proceedings of the 16th international conference on Telecommunications (2009)

In this paper, we study the throughput enhancement in a wireless slotted ALOHA system, where all users transmit space-time coded information sequences and the destination is able to separate a given number of collided packets. These users operate with the slotted ALOHA protocol to access to the wireless channel resulting in a high probability of collision. To increase the packet throughput of such a system, we propose to separate the collided packets at the destination with a successive interference canceller that performs joint detection: channel estimation and data detection. The multi-user detector that we propose exploits the benefits of both the collision processing and the space-time signature induced by the Alamouti-type space-time block coding to improve the throughput. The validity of the proposed algorithm is highlighted by simulation results.
On networks with side information
Authors: Asaf Cohen, Salman Avestimehr, Michelle Effros
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

In this paper, we generalize the lossless coded side information problem from the three-node network of Ahlswede and Körner to more general network scenarios. We derive inner and outer bounds on the achievable rate region in the general network scenario and show that they are tight for some families of networks. Our approach demonstrates how solutions to canonical source coding problems can be used to derive bounds for more complex networks and reveals an interesting connection between networks with side information, successive refinement, and network coding.
A QoS-aware and fair resource allocation scheme for WPANs
Authors: Xueli An, Ramin Hekmat
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

In this paper, we propose a new resource allocation scheme for Wireless Personal Area Networks (WPANs). The novelty of this scheme is in its capability to combine, in a dynamic way, QoS with fairness in resource allocation. This makes our scheme a suitable solution for supporting heterogeneous services in WPANs. In order to be QoS-aware we make use of preassigned service priorities. Further, in order to add fairness, our scheme is capable of assigning higher medium access priorities to the backlogged traffic flows. Using OPNET, extensive simulations have been done to compare the performance of the proposed policy with two QoS-unaware and unfair scheduling algorithms: First-Come-First-Served (FCFS) and Directional Transmission Scheduling (DTS). Simulation results indicate that our proposal can substantially improve system performance in terms of the delay-based fairness and job failure ratio.
Efficient data management using the session log in DHT and its evaluation
Authors: Satoru Noguchi, Atsuo Inomata, Kazutoshi Fujikawa, Hideki Sunahara
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Distributed Hash Table (DHT) is a specialized distributed system that aims to lookup hashed identifiers efficiently in order to route messages to and from the corresponding nodes and objects. However DHTs are mechanisms sensitive to churn (the continuous and interleaved process of arrival / departure of nodes). As a result, they often cause loss of stored objects and failures in the lookup, a serious issue for all overlay networks. In this paper, we propose a dynamic replica location method using the session log in DHT. Our method can determine dynamically the effective number of replicas on session running periods among anticipate nodes. We also implemented a prototype based on an existing DHT routing algorithm, and we evaluated the performance of the prototype. Our proposed method was shown to reduce data loss and the cost for locating replication.
A simulation study on the energy efficiency of pure and slotted aloha based RFID tag reading protocols
Authors: R. Alejandro Ruiz, Dheeraj K. Klair, Kwan-Wu Chin
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

This paper studies the energy efficiency of twelve Pure and Slotted Aloha tag reading protocol variants via simulation. We compare their energy consumption in three collision resolution phases: 1) success, 2) collision, and 3) idle. Our extensive simulation results show that Pure Aloha with fast mode and muting has the lowest energy consumption, and hence is most suited for deployment in energy-constrained environments.
On the closure of families of fuzzy measures under eventwise aggregations
Authors: A. G. Bronevich
Venue: Fuzzy Sets and Systems (2005)

The paper contains some results on eventwise aggregation of fuzzy measures from the various families of lower probabilities. This investigation includes coherent lower probabilities, k-monotone measures', belief measures, etc. We study sufficient and necessary conditions on aggregation operators satisfying the closure property: it is necessary to guarantee that the aggregation belongs to the same family, as generating measures. We also propose an efficient way for constructing aggregation operators, using the found unique properties of multilinear extension. This representation method for fuzzy measures generalizes to the n-dimensional case the well-known one giving distorted probabilities.
Applications of the naturalness preserving transform to image watermarking and data hiding
Authors: Ayman M. Ahmed, Dwight D. Day
Venue: Digital Signal Processing (2004)

The paper presents an image watermarking technique using the naturalness preserving transform (NPT). The goal is to produce an invisible and robust watermark that resists signal processing and geometric distortion attacks. Unlike traditional techniques, the proposed algorithm inserts and extracts the watermark via a special orthogonal transform class in between the spatial and frequency representations of the host image data. Two modified forms of the NPT employing the Hartley and discrete cosine transforms, respectively, are presented in order to improve the quality of the transformed image. Enhancements for the quality of the transformed images are achieved via reduction to the artifacts that occur to images transformed via the classical Hadamard-based NPT. The proposed watermark has demonstrated robustness against a variety of image attacks including, JPEG compression, low pass filtering, image cropping, and noise. The marked image must be severely degraded in order to prevent the reconstruction of the watermark.
Decoding algorithms for binary raptor codes over nonbinary channels
Authors: Harm S. Cronie, Bertrand Ndzana Ndzana, Amin Shokrollahi
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

In this paper, we introduce a class of decoding algorithms for binary Raptor codes used for transmission over q-ary channels, where q = 2m. The algorithms provide a trade-off between complexity and decoding capability. Whereas the running time of the q-ary belief-propagation algorithms is m2m times that of its binary counterpart, in our case the complexity factor can be chosen between m and 2m, depending on the error-correction capability required. As such, the running time can be much better than the q-ary belief-propagation algorithm. The main idea behind our algorithm is to apply an appropriate set of GF(2)-linear forms of GF(q) to the Raptor code to obtain a set of binary codes which can be decoded independently in parallel. After a prescribed number of iterations, for each of the input symbols of the Raptor code and each of the linear forms an estimate is obtained on the probability that this linear form applied to the input symbol is zero. By gathering these probabilities and performing a maximum-likelihood decoding on a suitable code of very small blocklength, we are able to obtain a good estimate of the value of the input symbol. Simulations results are provided for a families of q-ary symmetric channels and non-symmetric channels which show the performance of our decoding algorithms.
Design of high efficiency switching mode power amplifier for RF and micro-wave
Authors: Z. Nadir, F. Touati
Venue: Proceedings of the 16th international conference on Telecommunications (2009)

This paper investigates the highly efficient design of switching mode class E power amplifier for frequencies of 900 MHz and 1800 MHz to increase the efficiency of cellular phones batteries thus by reducing the power consumed in the power amplifier. This is the continuation of an ongoing work by the authors. Here, a typical class E circuit design steps are shown for 1800 MHz in addition to the circuit designed for 900MHz. Both circuits are designed using MOSFET. The simulated results were compared with each other in terms of output power, dissipated power in the transistor, harmonics and efficiency. For this, some additional parameters are simulated and presented for better comparison. Efficiencies higher than 67% could be achieved.
Concatenated fountain codes
Authors: Zheng Wang, Jie Luo
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

This paper investigates fountain communication over discrete-time memoryless channels. Fountain error exponent achievable by linear complexity concatenated fountain codes is derived.
To code or not to code: rate optimality in node-capacitated networks
Authors: Ziyu Shao, Sidharth Jaggi, Shuo-Yen Robert Li
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

Node-capacitated networks are networks in which the capacity constraint is put on every node. They have recently attract attention as a good model for Peer-to-Peer (P2P) overlay networks. Existing work gives results on networks with constraints of node upload capacities. In this paper, we consider networks with constraints on both node upload and node download capacity. For such networks, we investigate the rate optimality of routing versus network coding. In general, network coding achieves a larger rate region than routing. However, for some important communication scenarios, routing achieves the same rate region as network coding.
Hop-count based node-to-anchor distance estimation in wireless sensor networks
Authors: Di Ma, Bang Wang, Hock Beng Lim, Meng Joo Er
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Localization is one of the most important research issues in Wireless Sensor Networks (WSNs). Hop-count based localization has been proposed as a cost-effective alternative to the expensive hardware-based localization schemes. In this paper, we propose a new method to estimate distances between anchors and nodes based on hop-count information. Localization is then achieved using the estimated distances. Simulation results show that the performance of our proposed algorithm is much better than that of the DV-hop algorithm [1] in terms of the node-to-anchor distance estimation and localization accuracy, and the improvement is proportional to the node density.
One family of algebraic codes for network coding
Authors: Martin Bossert, Ernst M. Gabidulin
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

The subspace metric is a subject of intensive researche recently. Nevertheless not much is known about codes in this metric in general. In this paper, one class of subspace metric based codes is defined. This class is a generalization of a Koetter-Kshishang-Silva construction, namely, the lifting construction. Also, a quasi-Singleton bound is derived which is tighter than the Koetter-Kschischang bound for large dimensions of subspaces.
Adaptive block DFT-LMS signal detection in ultra-wideband communications
Authors: Chia-Chang Hu, Wei-Ciao Jhu
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

An adaptive block DFT-LMS (B-DFT-LMS) filter is an efficient scheme to detect users' signals in the impulse radio ultra-wideband (IR-UWB) systems. The B-DFT-LMS adaptive filter processes data on a block-by-block basis, as opposed to a sample-by-sample basis. This adaptive block filter provides almost the same mean-square-error (MSE) as the recursive least squares (RLS) adaptive filter and possesses a superior convergence rate than the conventional LMS and the normalized LMS (NLMS) filters. Simulations are performed to illustrate the MSE performance and convergence characteristic in the time-hopping (TH) and the direct-sequence (DS) UWB communication systems.
Virtualization for advanced power management of consumer electronic devices
Authors: Frank Altschuler, Vincent Palatin
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

We describe the use of a dedicated power management virtual machine in the context of portable consumer electronics devices. The high level architecture and inter-virtual machine dependencies are discussed as well as key power management strategies and issues.
Performance limits of OWSS: A spectrally efficient WLAN system
Authors: V. K. Jain, D. Divakaran, B. A. Myers
Venue: Digital Signal Processing (2005)

Orthogonal wavelet spread spectrum (OWSS) is a new wireless LAN signaling scheme aimed at bit rates of 100 Mbps or higher. Starting with power complementary full-tree wavelet pulses, it spreads them using a suitable set of PN codes. The resulting system pulses preserve the power complementary property and satisfy the generalized Nyquist criterion, while possessing both a wide time and a wide frequency support. Benefits from these properties include successful equalization in spite of deep local fades caused by multipath channels, and high spectral efficiency-30-40% higher than OFDM for comparable net bit rates. This paper presents an overview of OWSS and explores the fundamental limits to its performance. In the overview, it discusses the properties of the OWSS pulses, the transmit signal spectrum, and the structure of the transmitter/receiver. Then, the investigation of fundamental limits to the performance is carried out by formulating the system as a multi-rate signal processing system, using hierarchical matrices, and thereupon minimizing the total mean-square error (TMSE). The TMSE governs the BER performance of the system, and is defined as the sum of the MSE of the unequalized residual error and the MSE due to the channel noise amplified by the forward equalizer. We formulate the problem at the chip level so as to truly discern the fundamental limits to the performance of the equalizer. This approach enables estimation of the optimum equalizer for mitigating the effect of the multipath channel, prior to correlation and detection blocks embedded in the FE-DFE loop, and thereby the system performance. Simulation results demonstrate its effectiveness. For a 108 Mbps system with a 50 ns delayspread channel, a low BER of 10^-^5 and spectral efficiency up to 5.2 bits/s/Hz can be achieved at an Eb/No of 19 dB.
A benchmark-based estimation approach for network operation cost reduction with shared delivery options
Authors: Thomas Frisanco
Venue: Proceedings of the 16th international conference on Telecommunications (2009)

The formation of new, emerging-market "regional champion" multi-country telecommunications network operators drives the demand for innovative, cross-country delivery platforms for network operations. Both strategic and economic aspects need to be taken into account when determining the optimal, resource-sharing re-design of network operations processes. At the same time, outsourcing options need to be evaluated. We present a comprehensive methodology for assessing various alternatives for providing network operations, and introduce a benchmark-based model for estimating potential cost reductions.
A method for normalizing histology slides for quantitative analysis
Authors: Marc Macenko, Marc Niethammer, J. S. Marron, David Borland, John T. Woosley, Xiaojun Guan, Charles Schmitt, Nancy E. Thomas
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

Inconsistencies in the preparation of histology slides make it difficult to perform quantitative analysis on their results. In this paper we provide two mechanisms for overcoming many of the known inconsistencies in the staining process, thereby bringing slides that were processed or stored under very different conditions into a common, normalized space to enable improved quantitative analysis.
An SDP primal-dual algorithm for approximating the Lovász-theta function
Authors: T.-H. Hubert Chan, Kevin L. Chang, Rajiv Raman
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

The Lovász Θ-function [Lov79] on a graph G = (V, E) can be defined as the maximum of the sum of the entries of a positive semidefinite matrix X, whose trace Tr(X) equals 1, and Xij = 0 whenever {i, j} ∈ E. This function appears as a subroutine for many algorithms for graph problems such as maximum independent set and maximum clique. We apply Arora and Kale's primal-dual method for SDP to design an approximate algorithm for the Θ-function with an additive error of δ > 0, which runs in time O(α2n2/δ2 logn ċ Me), where α = Θ(G) and Me = O(n3) is the time for a matrix exponentiation operation. Moreover, our techniques generalize to the weighted Lovász Θ-function, and both the maximum independent set weight and the maximum clique weight for vertex weighted perfect graphs can be approximated within a factor of (1+ơ) in time O(ơ-2n5 log n).
On the degrees of freedom of the 3-user Gaussian interference channel: the symmetric case
Authors: Abolfazl Seyed Motahari, Shahab Oveis Gharan, Amir Keyvan Khandani
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

In this paper, the Degrees Of Freedom (DOF) of the symmetric 3-user Gaussian interference channel is considered. It is shown that by using un-coded signaling, the achievable DOF is a discontinuous function of the channel parameter. More importantly, for the set of irrational channel gains, which has measure 1 in real numbers, it is proved that the total system's DOF, i.e., 3/2, is achievable. This result is obtained using Hurwitz's theorem in number theory.
A new variational method to detect points in biological images
Authors: Daniele Graziani, Laure Blanc-Féraud, Gilles Aubert
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

We propose a new variational method to isolate points in biological images. As points are fine structures they are difficult to detect by derivative operators computed in the noisy image. In this paper we propose to compute a vector field from the observed intensity so that its divergence explodes at points. As the image could contains spots but also noise and curves where the divergence also blows up, we propose to capture spots by introducing suitable energy whose minimizers are given by the points we want to detect. In order to provide numerical experiments we approximate this energy by means of a sequence of more treatable functionals by a Γ-convergence approach. Results are shown on synthetic and biological images.
Expansion segmentation for visual collision detection and estimation
Authors: Jeffrey Byrne, Camillo J. Taylor
Venue: Proceedings of the 2009 IEEE international conference on Robotics and Automation (2009)

Collision detection and estimation from a monocular visual sensor is an important enabling technology for safe navigation of small or micro air vehicles in near earth flight. In this paper, we introduce a new approach called expansion segmentation, which simultaneously detects "collision danger regions" of significant positive divergence in inertial aided video, and estimates maximum likelihood time to collision (TTC) in a correspondenceless framework within the danger regions. This approach was motivated from a literature review which showed that existing approaches make strong assumptions about scene structure or camera motion, or pose collision detection without determining obstacle boundaries, both of which limit the operational envelope of a deployable system. Expansion segmentation is based on a new formulation of 6- DOF inertial aided TTC estimation, and a new derivation of a first order TTC uncertainty model due to subpixel quantization error and epipolar geometry uncertainty. Proof of concept results are shown in a custom designed urban flight simulator and on operational flight data from a small air vehicle.
The capacity region of a class of deterministic Z channels
Authors: Viveck R. Cadambe, Syed A. Jafar, Sriram Vishwanath
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

We characterize the capacity region of a class of the deterministic Z channels. We show that, interestingly, Han-Kobayashi type rate-splitting is not required in the optimal achievable scheme for the class of channels considered.
A cluster-based framework for spontaneous collaboration without infrastructure
Authors: Juan A. Martinez, Francisco J. Galera, Miguel A. Sanchis, Antonio F. Gomez-Skarmeta
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

In this paper, the authors describe the development of a framework for collaborative spontaneous networks. A spontaneous network is created when a group of users comes together and uses wireless computing devices in order to carry-out a collaborative activity. The target of this framework is to provide efficient communications for groups of users in such a scarce resource environment. The architecture proposed in this work is based on three main design decisions: multicast technology is used to reduce the traffic, a clustering scheme has been proposed to minimize the network overhead and a cross-layer adaptation between our framework and the multicast routing protocol allows our architecture to take advantage of the network topology information collected by the routing protocols at the network layer. The experiments performed using a real testbed show that the framework provides rapid response times in static and dynamic environments.
On cyclic frequency diversity for single-carrier packet retransmissions
Authors: Abdel-Nasser Assimi, Charly Poulliat, Inbar Fijalkow
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

In this paper, we investigate the use of cyclic frequency diversity (CFD) scheme for single-carrier packet retransmission over frequency-selective channels in the context hybrid automatic repeat request protocols (HARQ). For each retransmission of the same packet, the transmitted signal is cyclically shifted in the frequency-domain in order to compensate for channel fading over a part of the channel bandwidth in the previous transmissions. We consider efficient frequency-domain equalization based on the minimum mean square error (MMSE) criterion. We determine an optimal solution for frequency-shift values in order to maximize system throughput by maximizing the signal to interference-plus-noise ratio (SINR) at the output of the joint MMSE equalizer. The CFD scheme has low complexity and provides a substantial gain in terms of frame error rate, especially for high rate channel coding.