ppxscal/embedding_network huggingface dataset:
Diversity-multiplexing tradeoff of the dynamic decode and forward protocol on a MIMO half-duplex relay channel
Authors: Sanjay Karmakar, Mahesh K. Varanasi
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

We compute the diversity-multiplexing tradeoff (DMT) curve for a three node multi-input-multi-output (MIMO) half-duplex (HD) relay network, operating in the dynamic decode-and-forward (DDF) [1] mode. We consider the case where the source and the destination have n antennas each and the single relay node has m antennas. Denoting such a channel as a (n, m)-relay channel, we provide an analytical characterization of the DMT curve for certain simple configurations such as (n,1), (1,m) and (2,2). We employ a numerical method to compute the DMT for more general channel configurations. Interestingly, for low multiplexing gains the achievable diversity orders of the HD-DDF protocol coincides with the diversity orders achieved by the full-duplex decode-and-forward (FDDF) protocol analyzed in [2]. In fact, the HD-DDF and FDDF protocols achieve the same diversity orders for all integer multiplexing gains. Thus, the half duplex constraint does not significantly affect the achievable DMT for the DF protocol when the source and the destination have the same number of antennas.
Collaborative multimedia collection for enriching and visualizing 3D underwater sites
Authors: Nader Cheaib, Samir Otmane, Malik Mallem
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

In this paper, we present a research work in the context of a national project, DIGITAL OCEAN for the creation and distribution of multimedia content, where we present tailorable groupware architecture, Oce@nyd, to allow a collaborative collection of multimedia information over the internet. The Oce@nyd architecture is based on Web services and software agents' integration. This research is, until now, never been exploited in the context of groupware tailorability, hence bringing innovation in the CSCW (Computer Supported Cooperative Work) domain. We apply our research work on DIGITAL OCEAN in order to give users means to collaborate more efficiently, for the purpose of enriching underwater maps with up-to-date multimedia files, as well as means to tailor the services proposed in the system in order to adapt the system to their preferences, and hence enhance collaboration.
Performance analysis of slotted ALOHA based multi-channel cognitive packet radio network
Authors: Sangho Choe
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

In this paper we present a slotted ALOHA based multi-channel cognitive radio network opportunistically using the unused spectrum of incumbent devices and analyze its throughput and delay. We also evaluate packet capture effect of our proposed system over Rayleigh fading.
An agent framework for CE devices to support storage virtualization on device ensembles
Authors: Woojoong Lee, Young-Ki Hong, Chanik Park
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

The problem of accessing and managing digital contents scattered on personal portable devices such as smart phone, digital camera, MP3 player, or laptop in an integrated fashion is critical in ubiquitous computing. It is not trivially solvable because the underlying networks are dynamically configured and the data types supported by each device are constrained. Due to recent rapid growth in personal digital contents, it becomes a major issue. To address this challenge, we have proposed a self-managed distributed file services called PosCFS+ [1], [2], [3] in personal area networks (PAN). PosCFS+ automatically detects every devices available in PAN and integrates the storage space of all the devices into a virtual storage. In order to facilitate data access to the virtual storage, PosCFS+ creates virtual directories which enable a semantic file addressing from applications. However, in a real world consisting of multiple consumer electronics (CE) devices, it is not easy or even impossible to install software components like PosCFS+ in the CE devices because they are proprietary. In this paper, we present the design and implementation of a CE device agent which enables the storage virtualization by PosCFS+ on CE device ensembles. Most CE devices are connected to a host computer via USB interface, so the agent will be executed on the host computer to export the physical storage space of a CE device to PosCFS+. Then, virtual storages and virtual directories are created by PosCFS+ according to predefined user profile. Finally, to solve the problem of limited data type and format supported in a CE device, the event notification framework proposed in [3] is used for automatic data transcoding.
On 3-receiver broadcast channels with 2-degraded message sets
Authors: Chandra Nair, Zizhou Vincent Wang
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

We consider a broadcast channel with 3 receivers and 2 messages (M0, M1) where two of the three receivers need to decode messages (M0, M1) while the remaining one just needs to decode the message M0. We study the best known inner and outer bounds under this setting, in an attempt to find the deficiencies with the current techniques of establishing the bounds. We produce a simple example where we are able to explicitly evaluate the inner bound and show that it differs from the general outer bound. For a class of channels where the general inner and outer bounds differ, we use a new argument to show that the inner bound is tight.
Service delivery framework for DVB-H and EPS
Authors: Uma Shanker, A. Hamid Aghvami, Achim Gottscheber
Venue: Proceedings of the 16th international conference on Telecommunications (2009)

Seamless service handover is an important factor for the success of new services in the integrated network environment. Most of the current solutions for the interworking of networks, which generally rely on the physical layer handover between different networks such as mobile cellular or broadcast networks, does not necessarily considers the application level issues such as service continuation or associated services. Handover association table based approach can easily be used for solving service continuation problems. In this paper we look at the framework which not only allows for seamless service continuation between heterogeneous networks but can also be extended to accumulate further service provisioning. This framework can enrich the user experience and provide base for dynamic service delivery based on the user promes by associating related services. Current article gives details of framework design, its implementation and evolution. Additionally, we also show how this framework can be used for the E-MBMS service provisioning in the interworking of EPS and DVB-H networks.
Graph wavelet applied to human brain connectivity
Authors: Pierre Besson, Christine Delmaire, Vianney Le Thuc, Stéphane Lehéricy, Florence Pasquier, Xavier Leclerc
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

The graph theory is increasingly used and provides powerful tools for studying complex biological networks problems. They were able to characterize the small-worldness of the brain connectivity network and were accurate enough to observe topological differences between healthy and diseased brain graphs. However, these methods relied on topological characteristics implying that differences could be observed between two groups only if corresponding graphs topologies were different. In this paper, we developed a multiscale method to characterize fine to coarse brain connectivity, which allows to observe connectivity differences between two groups even if corresponding graphs topologies are identical. For this purpose, we defined a new wavelet graph transform based on the interval wavelet transform. Our method decomposes the connectivity values of a graph regardless of its topology, can be defined with a large spectrum of wavelet bases and is invertible. Finally, we applied our graph wavelet decomposition on brain connectivity graph in a group of healthy controls.
Hemodynamic alterations of a patient-specific intracranial aneurysm induced by virtual deployment of stents in various axial orientation
Authors: Minsuok Kim, Ignacio Larrabide, Maria-Cruz Villa-Uriol, Alejandro F. Frangi
Venue: Proceedings of the Sixth IEEE international conference on Symposium on Biomedical Imaging: From Nano to Macro (2009)

The aim of this study is to investigate the influence of stent axial orientation on saccular aneurysm hemodynamics. Two commercial stents, Neuroform stent (stent 1) and Zilver stent (stent 2) are modeled in this study. Both stents are virtually deployed with four different axial orientations to fit into the luminal surface of a patient-specific internal carotid artery (ICA) aneurysm model. Computational hemodynamic analyses are carried out in unstented and stented aneurysm models. The intra-aneurismal flows of stented aneurysm models show disturbed and complex flow patterns while the flow activities and the forces acting on the aneurysm wall are generally alleviated by stenting. The influence of the axial orientation of the stent on the aneurysm hemodynamics is more significant for stent 2 which has a larger strut size compared to stent 1. Interestingly, the flow activity in the aneurysm is rather increased when the intra-luminal scaffolding of stent is not sufficient.
An experimental study of packet loss and forward error correction in video multicast over IEEE 802.11b network
Authors: Özgü Alay, Thanasis Korakis, Yao Wang, Shivendra Panwar
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

Video multicast over Wireless Local Area Networks (WLANs) faces many challenges due to varying channel conditions and limited bandwidth. A promising solution to this problem is the use of packet level Forward Error Correction (FEC) mechanisms. However, the adjustment of the FEC rate is not a trivial issue due to the dynamic wireless environment. This decision becomes more complicated if we consider the multi-rate capability of the existing wireless LAN technology that adjusts the transmission rates based on the channel conditions and the coverage range. In order to explore the above issues we conducted an experimental study of the packet loss behavior of the IEEE 802.11b protocol. In our experiments we considered different transmission rates under the broadcast mode in indoor and outdoor environments. We further explored the effectiveness of packet level FEC for video multicast over wireless networks with multi-rate capability. In order to evaluate the system quantitatively, we implemented a prototype using open source drivers and socket programming. Based on the experimental results, we provide guidelines on how to efficiently use FEC for wireless video multicast in order to improve the overall system performance.We show that the Packet Error Rate (PER) increases exponentially with distance and using a higher transmission rate together with stronger FEC is more efficient than using a lower transmission rate with weaker FEC for video multicast.
Information secrecy from multiple eavesdroppers in orthogonal relay channels
Authors: Vaneet Aggarwal, Lalitha Sankar, A. Robert Calderbank, H. Vincent Poor
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

The secrecy capacity of relay channels with orthogonal components is studied in the presence of additional passive eavesdropper nodes. The relay and destination receive signals from the source on two orthogonal channels such that the destination also receives transmissions from the relay on its channel. The eavesdropper(s) can overhear either one or both of the orthogonal channels. For a single eavesdropper node, the secrecy capacity is shown to be achieved by a partial decode-and-forward (PDF) scheme when the eavesdropper can overhear only one of the two orthogonal channels. For the case of two eavesdropper nodes, secrecy capacity is shown to be achieved by PDF for a sub-class of channels.
An iterative algorithm for trust and reputation management
Authors: Erman Ayday, Hanseung Lee, Faramarz Fekri
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

Trust and reputation play critical roles in most environments wherein entities participate in various transactions and protocols among each other. The recipient of the service has no choice but to rely on the reputation of the service provider based on the latter's prior performance. This paper introduces an iterative method for trust and reputation management referred as ITRM. The proposed algorithm can be applied to centralized schemes, in which a central authority collects the reports and forms the reputations of the service providers as well as report/rating trustworthiness of the (service) consumers. The proposed iterative algorithm is inspired by the iterative decoding of low-density parity-check codes over bipartite graphs. The scheme is robust in filtering out the peers who provide unreliable ratings. We provide a detailed evaluation of ITRM via analysis and computer simulations. Further, comparison of ITRM with some well-known reputation management techniques (e.g., Averaging Scheme, Bayesian Approach and Cluster Filtering) indicates the superiority of our scheme both in terms of robustness against attacks (e.g., ballot-stuffing, bad-mouthing) and efficiency. Furthermore, we show that the computational complexity of the proposed ITRM is far less than the Cluster Filtering; which has the closest performance (to ITRM) in terms of resiliency to attacks. Specifically, the complexity of ITRM is linear in the number of clients, while that of the Cluster Filtering is quadratic.
Remuneration aware resource acquisition in p2p overlay
Authors: Joseph C. H. So, P. C. Wong
Venue: Proceedings of the 6th IEEE Conference on Consumer Communications and Networking Conference (2009)

In content delivery services, quality of service is greatly affected by the resources provided by the underlying overlay P2P. In order to maintain the level of resources acquired, soliciting peers' resources contributions by giving explicit remunerations is a feasible solution. From the service providers' perspectives, the remuneration should be minimized as long as the guaranteed services are fulfilled for all users. We consider a model defining the objective function to minimize this cost in service provision and a distributed and cost-efficient resource acquisition algorithm. Our results show that, in a network of the heterogeneous peers with limited local information, the service availability can be enhanced by appropriate resource acquisition schemes even in a heavily loaded network and the number of resource providers can be controlled by applying appropriate cost model.
Diversity-multiplexing tradeoff for the MIMO static half-duplex relay
Authors: Olivier Lévêque, Christophe Vignat, Melda Yuksel
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

In this work, we investigate the diversity-multiplexing tradeoff (DMT) of the multiple-antenna (MIMO) static half-duplex relay channel. The relay channel is assumed to be symmetric in terms of number of antennas, i.e, the source and the destination have n antennas each, and the relay has m antennas. A general expression is derived for the DMT upper bound, which can be achieved by a compress-and-forward protocol at the relay, under certain assumptions. It is observed that the static half-duplex DMT matches the full-duplex DMT when the relay has a single antenna, and is strictly below the full-duplex DMT when the relay has multiple antennas.
Levy process-driven mean-reverting electricity price model: the marginal distribution analysis
Authors: Shi-Jie Deng, Wenjiang Jiang
Venue: Decision Support Systems (2005)

We propose a class of stochastic mean-reverting models for electricity prices with Levy process-driven Ornstein-Uhlenbeck (OU) processes being the building blocks. We first fit marginal distributions of power price series to two special classes of distributions defined by quantile functions (termed Class I and Class II distributions). A theoretical correlation structure is then used to fit the empirical autocorrelation structure. Lastly, based on results from the first two steps, we construct a stochastic process by superposing two OU processes. The focus of this paper is on fitting the marginal distribution. A Class I distribution has closed-form formulas for probability density, cumulative distribution function, and quantile function, while a Class II distribution may have extremely unbalanced tails. Both classes of distributions admit realistic modelling of the marginal distribution of electricity prices. This approach effectively captures not only the anomalous tail behaviors but also the correlation structure present in the electricity price series.
The capacity region of the symbol-asynchronous Gaussian multiple-access channel with orthogonal signaling
Authors: Hon-Fah Chong, Mehul Motani
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

Verdu determined the capacity region of the symbol-asynchronous two-user Gaussian multiple-access channel [1]. In this channel, each user modulates a fixed waveform in each symbol period and the symbol periods for the users do not coincide at the receiver. First, he explicitly evaluated the capacity region of this class of multiple-access channels in the case where the transmitters know the offset. The result was also extended to the case where the transmitters have no knowledge of the offset. In this paper, we extend the result to the case where each user modulates K orthogonal waveforms and the transmitters know the offset. In addition, the users' orthogonal waveforms are not assumed to be identical. Similar to the case where each user is allowed to modulate a fixed waveform, the result holds regardless of whether or not the transmitters are frame-asynchronous. We later extend the result to certain situations where the transmitters do not know the offset.
Optimal, systematic q-ary codes correcting all asymmetric errors of limited magnitude
Authors: Noha Elarief, Bella Bose
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

Systematic q-ary (q > 2) codes capable of correcting all asymmetric errors of maximum magnitude l, where l ≤ q-2, are given. These codes are shown to be optimal. Further, simple encoding/decoding algorithms are described.
Throughput enhancements in point-to-multipoint cognitive systems
Authors: N. Jamal, H. Ebrahimzadeh Saffar, P. Mitran
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

We consider the coexistence of collocated primary and secondary point-to-multipoint systems such as cellular systems that simultaneously access the same spectrum. In particular, we analyze the number of users and sum-rate of the secondary system as a function of the maximum impact it is allowed to have on the primary system when simultaneous transmissions are treated as interference. As a base reference, we compare to channel sharing via time division (TD). We find that provided the secondary system is given sufficient channel state information, the impact of the interference to the primary system on its sum-rate can be mitigated by judicious choice of the active secondary nodes and quantify the improvement that is realized. This quantification is achieved by a key lemma on the sum of low order statistics of an exponential random variable. We also analyze the more symmetric case when both primary and secondary networks are given sufficient channel state information to selectively activate nodes.
The Shannon cipher system with a guessing wiretapper: general sources
Authors: Manjesh Kumar Hanawal, Rajesh Sundaresan
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 3 (2009)

The Shannon cipher system is studied in the context of general sources using a notion of computational secrecy introduced by Merhav & Arikan. Bounds are derived on limiting exponents of guessing moments for general sources. The bounds are shown to be tight for iid, Markov, and unifilar sources, thus recovering some known results. A close relationship between error exponents and correct decoding exponents for fixed rate source compression on the one hand and exponents for guessing moments on the other hand is established.
Analytical solution of covariance evolution for regular LDPC codes
Authors: Takayuki Nozaki, Kenta Kasai, Kohichi Sakaniwa
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

The covariance evolution is a system of differential equations with respect to the covariance of the number of edges connecting to the nodes of each residual degree. Solving the covariance evolution, we can derive distributions of the number of check nodes of residual degree 1, which helps us to estimate the block error probability for finite-length LDPC code. Amraoui et at. resorted to numerical computations to solve the covariance evolution. In this paper, we give the analytical solution of the covariance evolution.
On noncoherent correction of network errors and erasures with random locations
Authors: Svitlana Vyetrenko, Tracey Ho, Elona Erez
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2 (2009)

We consider the problem of correcting errors and erasures with network coding. Unlike existing works which consider performance limits for worst-case locations of given numbers of errors and erasures, we consider the performance of given (not necessarily optimal) coding and forwarding strategies for given (not necessarily worst-case) models of error and erasure locations. Our approach characterizes decoding success in terms of the rank of certain matrices corresponding to useful and erroneous information received at the sink nodes. We use this approach to analyze random coding and forwarding strategies on a family of simple networks with random error and erasure locations, and show that the relative performance of the strategies depends on the erasure and error probabilities.
Analysis of the second moment of the LT decoder
Authors: Ghid Maatouk, Amin Shokrollahi
Venue: Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4 (2009)

We analyze the second moment of the ripple size during the LT decoding process and prove that the standard deviation of the ripple size for an LT-code with length k is of the order of √k. Together with a result by Karp et. al (2004) stating that the expectation of the ripple size is of the order of k, this gives bounds on the error probability of the LT decoder. We also give an analytic expression for the variance of the ripple size up to terms of constant order, and refine the expression of Karp et. al for the expectation of the ripple size up to terms of the order of 1/k, thus providing a first step towards an analytic finite-length analysis of LT decoding.