ppxscal/embedding_network huggingface dataset:
Rank-constrained separable semidefinite programming for optimal beamforming design
Authors: Yongwei Huang, Daniel P. Palomar
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

Consider a downlink communication system where multi-antenna base stations transmit independent data streams to decentralized single-antenna users over a common frequency band. The goal of the base stations is to jointly adjust the beamforming vectors so as to minimize the transmission powers while ensuring the signal-to-interference-noise ratio (SINR) requirement of individual users within the system, and keeping lower interference level to other systems which operate in the same frequency band and in the same region. This optimal beamforming problem is a separable homogeneous quadratically constrained quadratical programming (QCQP), and it is difficult to solve in general. In this paper, we give conditions under which strong duality holds, and propose an efficient algorithm for the optimal beamforming problem. First, we study rank-constrained solutions of a general separable semidefinite programming (SDP), and propose a rank reduction procedure to achieve a lower rank solution. Then we show that the SDP relaxation of a class of the optimal beamforming problem has a rank-one solution, which can be obtained by invoking the rank reduction procedure.
A local maximum intensity projection tracing of vasculature in knife-edge scanning microscope volume data
Authors: Donghyeop Han, John Keyser, Yoonsuck Choe
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

A local maximum intensity projection (MIP) approach to the extraction of a 3D vascular network, acquired by the Knife-Edge Scanning Microscope (KESM), is presented. We build a local volume for local MIP processing at each tracing step in order to reduce the dimension of input data from 3D to 2D, which leads to a 65.22% reduction of computation time compared to 3D tracing method. The proposed method makes use of existing 2D tracing methods, extending them into a 3D tracing method. Our experimental results show that our approach can rapidly and accurately extract the medial axis of vascular data acquired by the KESM.
Multiple-metric hybrid routing protocol for heterogeneous wireless access networks
Authors: Lijuan Cao, Kashif Sharif, Yu Wang, Teresa Dahlberg
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

The wireless multihop to an access point model appears to be a promising component of future network architectures, including multihop cellular networks and wireless access networks at the edges of mesh networks. Sophisticated software radios and core network protocols are being developed to support the integration of heterogeneous air interfaces within these access networks. A key challenge is managing diverse resources at access points (e.g., 3G, WiFi or WiMax) while discovering efficient multi-hop paths from a source to an access point based on selection criteria specified by various applications or necessitated by network resource constraints. We propose a new routing protocol that integrates multiple metrics to calculate path cost based on diverse selection criteria. In addition, a hybrid proactive/reactive anycast routing paradigm is applied to guide the discovery of an access point among multiple available access points. The result is an integrated, flexible protocol for route discovery and access point discovery. Simulation analysis shows that our approach outperforms single-metric routing protocols while supporting flexible service criteria, including load balancing at access points.
An energy efficient communication scheme with potential application to consumer and personal wireless networks
Authors: Koushik Sinha
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Applications requiring low power and quick turn on time (e.g., sensor networks) usually employ radios with only simple modulation techniques such as ASK, OOK and FSK [12]. We present in this paper a non-coherent detection based transceiver implementation for the RBNSiZeComm protocol proposed in [1], [2]. For a hybrid modulation scheme using FSK and ASK and assuming equal likelihood of all possible binary strings of a given length, we show that relative to binary FSK, there is a 41% savings in energy on an average at the transmitter, over additive white gaussian noise (AWGN) channels. Furthermore, our simulation results demonstrate that compared to binary FSK, for wireless application scenarios where longevity of power supply is a major concern (e.g., remote healthcare, streaming multimedia and agriculture wireless sensor networks) our proposed implementation can extend the battery life of devices from about 33% to 61% on an average, for the different communication data types used in these applications. Coupled with the low cost and low complexity of the transceiver, these savings demonstrate the usefulness of RBNSiZeComm for applications involving low power wireless networks.
Fisher information determinant and stochastic complexity for Markov models
Authors: Jun'ichi Takeuchi
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

We study Fisher information of stationary Markov models with a finite alphabet. In particular, we derive the Fisher information determinant of expectation parameter η, which is defined as expectation of Markov type. The Fisher information determinant with respect to Markov kernel parameter (conditional probabilities) is easy to find, while it is not so with respect to the expectation parameter η nor the natural parameter θ. Note that θ and η are of special importance for exponential families including Markov models.
Monotonic convergence of distributed interference pricing in wireless networks
Authors: Changxin Shi, Randall A. Berry, Michael L. Honig
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

We study distributed algorithms for allocating powers and/or adjusting beamforming vectors in a peer-to-peer wireless network which may have multiple-input-single-output (MISO) links. The objective is to maximize the total utility summed over all users, where each user's utility is a function of the received signal-to-interference-plus-noise ratio (SINR). Each user (receiver) announces an interference price, representing the marginal cost of interference from other users. A particular user (transmitter) then updates its power and beamforming vector to maximize its utility minus the interference cost to other users, which is determined from their announced interference prices. We show that if each transmitter update is based on a current set of interference prices and the utility functions satisfy certain concavity conditions, then the total utility is non-decreasing with each update. The proof is based on the convexity of the utility functions with respect to received interference, and applies to rate utility functions, and an arbitrary number of interfering MISO links. The extension to multi-carrier links is discussed as well as algorithmic variations in which the prices are not immediately updated after power or beam updates.
On the impact of the user terminal velocity on HSPA performance in MBMS multicast mode
Authors: Alessandro Raschellà, Anna Umbert, Giuseppe Araniti, Antonio Iera, Antonella Molinaro
Venue: Proceedings of the 16th international conference on Telecommunications (2009)

Multimedia Broadcast/Multicast Services (MBMS), introduced in Universal Mobile Telecommunication System (UMTS), have the aim to allow transmissions from a single source entity to multiple destinations. From the radio perspective, MBMS foresees both point-to-point (PtP) and point-to-multipoint (ptM) transmission mode, supported by Dedicated, Common, and Shared channels. The High Speed Downlink Packet Access (HSDPA), analyzed in this paper, can guarantee a higher data rate through the introduction of High Speed Downlink Shared Channel (HS-DSCH), thus improving the performance of MBMS transmissions. The aim of this paper is to investigate the impact of the User Equipment (UE) speed on the maximum number of users that the HS-DSCH can support forr MBMS applications. In particular, two different mobility profiles are taken into account (pedestrian and Vehicular) and the obtained results are validated by considering different transmission power levels, cell coverage sizes and bit rates.
A P2P, agent-based system of systems architecture for cooperative maritime networks
Authors: Sean J. Geoghegan, Grady McCorkle, Chris Robinson, Gregory Fundyler, Srini Ramaswamy, Jamelle Brown, Mhamed Itmi
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Cargo container shipping is a multi-billion dollar industry that involves hundreds of ships and millions of containers. These containers are typically sealed after they are loaded and remain sealed until they reach their final destination. An efficient and cost-effective method to ensure that container breaches are reported in a timely manner is needed. Using current off-the-shelf wireless technology and peer-to-peer networking techniques, an agent based framework is under development to monitor container status, port interactions and anomaly identification.
The capacity region of the parallel partially cooperative relay broadcast channel with unmatched degraded subchannels
Authors: Reza Khosravi-Farsani, Mahtab Mirmohseni, Bahareh Akhbari, Hamed Firouzi, Mohammad Reza Aref
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 1 (2009)

We investigate the parallel partially cooperative relay broadcast channel with unmatched degraded subchannels. We characterize the capacity region of this channel in the general setting that, transmitter sends a common message for both users and a private message for each of them. Our achievability result is based on the choosing appropriate parameters for the general achievable rate region of partially cooperative relay broadcast channel. We provide a converse proof for this achievable region as well, which establishes the capacity region.
Quantum LDPC codes with positive rate and minimum distance proportional to n 1/2
Authors: Jean-Pierre Tillich, Gilles Zémor
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

The current best asymptotic lower bound on the minimum distance of quantum LDPC codes with fixed non-zero rate is logarithmic in the blocklength. We build quantum LDPC codes with fixed non-zero rate and prove that their minimum distance grows proportionally to the square root of the blocklength.
Wavelet denoising with evolutionary algorithms
Authors: Adelino R. Ferreira da Silva
Venue: Digital Signal Processing (2005)

In recent years several wavelet thresholding schemes for denoising have been proposed. However, thresholding rules depend heavily on the choice of the parameters. Wavelet thresholding rules are typically nonlinear, leading to nonconvex target functions. In this paper, we present an evolutionary computation approach for parameter elicitation in penalized wavelet models. We begin with parameter models for global hard- and soft-thresholding. Then, we extend the methodology for parameter elicitation in two directions: block thresholding and best-basis denoising. The proposed evolutionary approach enables the joint optimization of wavelet basis selection and thresholding parameters for signal denoising. Numerical simulations are used to illustrate the proposed methodology and compare the behavior of the various denoising procedures.
An MMSE approach to the secrecy capacity of the MIMO Gaussian wiretap channel
Authors: Ronit Bustin, Ruoheng Liu, H. Vincent Poor, Shlomo Shamai
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

This paper provides a closed-form expression for the secrecy capacity of the multiple-input multiple-output (MIMO) Gaussian wiretap channel, under a power-covariance constraint. Furthermore, the paper specifies the input covariance matrix required in order to attain the capacity. The proof uses the fundamental relationship between information theory and estimation theory in the Gaussian channel, relating the derivative of the mutual information to the minimum mean-square error (MMSE). The proof provides the missing intuition regarding the existence and construction of an enhanced degraded channel that does not increase the secrecy capacity. The concept of enhancement has been used in a previous proof of the problem. Furthermore, the proof presents methods that can be used in proving other MIMO problems, using this fundamental relationship.
Relay-aided interference alignment for the quasi-static X channel
Authors: Behzad Nourani, Seyed Abolfazl Motahari, Amir K. Khandani
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

In this paper, we first introduce a simple procedure for aligning interference directions in an M × N user MIMO X channel. The scheme is then modified for an M × 2 user X channel in which each user is equipped with M + 1 antennas. Next we investigate the Degrees Of Freedom (DOF) for a single antenna X channel in slow fading environments with the help of a simple relay. The relay stores all the received signals and sends their linear combination in subsequent transmissions. Using this scheme, it is shown that adding a relay can help the system to achieve all the available DOF. It is also proved that if the relay's output power scales with P/(log P)s, there is no loss in the achieved DOF as long as s > 0. In other words, in a network with quasi-static channels, it is possible to achieve a higher DOF through the use of randomizing relays whose powers grow at a much slower rate than the main transmitters. Similarly, when there are stricter constraints on the output power scaling of the transmitters, all the DOF can still be utilized, if the relay power can grow with P(log P)t for any t > 0. These results suggest that adding relays to a network can be beneficial in terms of simultaneously acquiring higher DOF.
Robust methods for reconstructing brain activity and functional connectivity between brain sources with MEG/EEG data
Authors: Julia P. Owen, David P. Wipf, Hagai T. Attias, Kensuke Sekihara, Srikantan S. Nagarajan
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

The synchronous brain activity measured via magentoen-cephalography (MEG) or electroencephalography (EEG) arises from current dipoles located throughout the cortex. The number, location, time-course, and orientation of these dipoles, called sources, are estimated using a source localization algorithm. Source localization remains a challenging task, one that is significantly compounded by the effects of source correlations and interference from spontaneous brain activity and sensor noise. Likewise, assessing the interactions between the individual sources, known as functional connectivity, is also confounded by noise and correlations in the sensor recordings. In addition, computational complexity has been an obstacle to computing functional connectivity. This paper derives an empirical Bayesian method for performing source localization with MEG and EEG data that includes noise and interference suppression. We demonstrate that this method surpasses standard methods of localization. In addition, we demonstrate that brain source activity inferred from this algorithm is better suited to uncover the interactions between brain areas.
Capacity of compound state-dependent channels with states known at the transmitter
Authors: Pablo Piantanida, Shlomo Shamai
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

The problem of sending information over compound state-dependent channels with non-causal state information available at only the transmitter is investigated. We prove a coding theorem and its strong converse establishing the capacity of this scenario for the case of discrete memoryless channels. Specific results are derived for additive white Gaussian noise channels corrupted by an additive Gaussian interference which is available at the transmitter only. We focus on the case where such interference may be absent on the channel, but the transmitter is unaware of this. Applications of the com pound channels with non-causal state information arise in the context of multicast and cognitive radio channels, broadcast channels with imperfect channel knowledge and robust dirty-paper coding.
Deterministic relay networks with state information
Authors: Sung Hoon Lim, Young-Han Kim, Sae-Young Chung
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 1 (2009)

Motivated by fading channels and erasure channels, the problem of reliable communication over deterministic relay networks is studied, in which relay nodes receive a function of the incoming signals and a random network state. An achievable rate is characterized for the case in which destination nodes have full knowledge of the state information. If the relay nodes receive a linear function of the incoming signals and the state in a finite field, then the achievable rate is shown to be optimal, meeting the cut-set upper bound on the capacity. This result generalizes on a unified framework the work of Avestimehr, Diggavi, and Tse on the deterministic networks with state dependency, the work of Dana, Gowaikar, Palanki, Hassibi, and Effros on linear erasure networks with interference, and the work of Smith and Vishwanath on linear erasure networks with broadcast.
Influence of system geometry on motion tracking in echocardiographic image sequences
Authors: Basma Touil, Adrian Basarab, Olivier Bernard, Denis Friboulet
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

In this paper, we present a study on motion tracking in echocardiographic ultrasound images. The difficulty of motion estimation is linked to the fact that echographic image formation induces decorrelation between the underlying motion of tissue and the observed speckle motion. We investigate in this work the influence of speckle decorrelation on motion estimation from realistic simulations using Field II [6]. In particular, the analysis is performed for two simple motions: a translation and an incompressible deformation. The influence of decorrelation on speckle tracking accuracy is quantified using a conventional block matching (BM) algorithm and a more recent algorithm based on bilinear deformable block matching (BDBM). For all the simulations, the influence of the sectorial acquisition geometry is also investigated by performing motion estimation on Cartesian and polar data. Results show that decorrelation and loss of accuracy are significantly larger when motion estimation is performed from the conventional interpolated Cartesian data. In this perspective, we also show that the accuracy of motion estimation can be improved by using the BDBM algorithm, which may to some extent compensate for the deformation of the speckle patterns induced by decorrelation and sectorial geometry.
Consolidating achievable regions of multiple descriptions
Authors: Lei Zhao, Paul Cuff, Haim Pennuter
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 1 (2009)

In this paper, some existing inner bounds of multiple description problem are investigated. We prove that the El Gamal-Cover region [1] is a subset of the Zhang-Berger (ZB) region [7]. Furthermore, the Venkataramani-Kramer-Goyal region [8] is equivalent to the Zhang-Berger region.
Bayesian image analysis with on-line confidence estimates and its application to microtubule tracking
Authors: J. Cardinale, A. Rauch, Y. Barral, G. Székely, I. F. Sbalzarini
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

Automated analysis of fluorescence microscopy data relies on robust segmentation and tracking algorithms for sub-cellular structures in order to generate quantitative results. The accuracy of the image processing results is, however, frequently unknown or determined a priori on synthetic benchmark data. We present a particle filter framework based on Markov Chain Monte Carlo methods and adaptive annealing. Our algorithm provides on-line per-frame estimates of the detection and tracking confidence at run time. We validate the accuracy of the estimates and apply the algorithm to tracking microtubules in mitotic yeast cells. This is based on a likelihood function that accounts for the dominant noise sources in the imaging equipment. The confidence estimates provided by the present algorithm allow on-line control of the detection and tracking quality.
WCDMA interface in UMTS network carrying a mixture of multi-rate traffic with different priorities
Authors: Maciej Stasiak, Piotr Zwierzykowski, Janusz Wiewióra
Venue: Proceedings of the 16th international conference on Telecommunications (2009)

The paper presents an approximate method for modeling of the WCDMA interface in the UMTS network in which the mobile operator introduces priorities and user differentiation. In our considerations we use a model of the full-availability group servicing multi-rate traffic with priorities for services. In the proposed model we assnme that user priorities and the priorities for classes of services are introduced into the network. The proposed scheme is applicable for cost-effective WCDMA resource management in 3G mobile networks and can be easily applied to network capacity calculations.
The MIMO wireless switch: relaying can increase the multiplexing gain
Authors: Hassan Ghozlan, Yahya Mohasseb, Hesham El Gamal, Gerhard Kramer
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

This paper considers an interference network composed of K half-duplex single-antenna pairs of users who wish to establish bi-directional communication with the aid of a multi-input-multi-output (MIMO) half-duplex relay node. This channel is referred to as the "MIMO Wireless Switch" since, for the sake of simplicity, our model assumes no direct link between the two end nodes of each pair implying that all communication must go through the relay node (i.e., the MIMO switch). Assuming a delay-limited scenario, the fundamental limits in the high signal-to-noise ratio (SNR) regime is analyzed using the diversity-multiplexing tradeoff (DMT) framework. Our results sheds light on the structure of optimal transmission schemes and the gain offered by the relay node in two distinct cases, namely reciprocal and non-reciprocal channels (between the relay and end-users). In particular, the existence of a relay node, equipped with a sufficient number of antennas, is shown to increase the multiplexing gain; as compared with the traditional fully connected K-pair interference channel. To the best of our knowledge, this is the first known exam pIe where adding a relay node results in enlarging the pre-log factor of the sum rate. Moreover, for the case of reciprocal channels, it is shown that, when the relay has a number of antennas at least equal to the sum of antennas of all the users, static time allocation of decode and forward (DF) type schemes is optimal. On the other hand, in the non-reciprocal scenario, we establish the optimality of dynamic decode and forward in certain relevant scenarios.