Results for "Petar Veličković"

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Attentive cross-modal paratope predictionJun 12 2018Antibodies are a critical part of the immune system, having the function of directly neutralising or tagging undesirable objects (the antigens) for future destruction. Being able to predict which amino acids belong to the paratope, the region on the antibody ... More
X-CNN: Cross-modal Convolutional Neural Networks for Sparse DatasetsOct 01 2016In this paper we propose cross-modal convolutional neural networks (X-CNNs), a novel biologically inspired type of CNN architectures, treating gradient descent-specialised CNNs as individual units of processing in a larger-scale network topology, while ... More
Graph Attention NetworksOct 30 2017Feb 04 2018We present graph attention networks (GATs), novel neural network architectures that operate on graph-structured data, leveraging masked self-attentional layers to address the shortcomings of prior methods based on graph convolutions or their approximations. ... More
Cross-modal Recurrent Models for Weight Objective Prediction from Multimodal Time-series DataSep 23 2017Nov 29 2017We analyse multimodal time-series data corresponding to weight, sleep and steps measurements. We focus on predicting whether a user will successfully achieve his/her weight objective. For this, we design several deep long short-term memory (LSTM) architectures, ... More
Automatic Inference of Cross-modal Connection Topologies for X-CNNsMay 02 2018This paper introduces a way to learn cross-modal convolutional neural network (X-CNN) architectures from a base convolutional network (CNN) and the training data to reduce the design cost and enable applying cross-modal networks in sparse data environments. ... More
XFlow: 1D-2D Cross-modal Deep Neural Networks for Audiovisual ClassificationSep 02 2017We propose two multimodal deep learning architectures that allow for cross-modal dataflow (XFlow) between the feature extractors, thereby extracting more interpretable features and obtaining a better representation than through unimodal learning, for ... More
Quantifying the Effects of Enforcing Disentanglement on Variational AutoencodersNov 24 2017The notion of disentangled autoencoders was proposed as an extension to the variational autoencoder by introducing a disentanglement parameter $\beta$, controlling the learning pressure put on the possible underlying latent representations. For certain ... More
Towards Sparse Hierarchical Graph ClassifiersNov 03 2018Recent advances in representation learning on graphs, mainly leveraging graph convolutional networks, have brought a substantial improvement on many graph-based benchmark tasks. While novel approaches to learning node embeddings are highly suitable for ... More
ChronoMID - Cross-Modal Neural Networks for 3-D Temporal Medical Imaging DataJan 12 2019ChronoMID builds on the success of cross-modal convolutional neural networks (X-CNNs), making the novel application of the technique to medical imaging data. Specifically, this paper presents and compares alternative approaches - timestamps and difference ... More
X-CNN: Cross-modal Convolutional Neural Networks for Sparse DatasetsOct 01 2016Oct 17 2016In this paper we propose cross-modal convolutional neural networks (X-CNNs), a novel biologically inspired type of CNN architectures, treating gradient descent-specialised CNNs as individual units of processing in a larger-scale network topology, while ... More
Deep Graph InfomaxSep 27 2018Dec 21 2018We present Deep Graph Infomax (DGI), a general approach for learning node representations within graph-structured data in an unsupervised manner. DGI relies on maximizing mutual information between patch representations and corresponding high-level summaries ... More
Spatio-Temporal Deep Graph InfomaxApr 12 2019Spatio-temporal graphs such as traffic networks or gene regulatory systems present challenges for the existing deep learning methods due to the complexity of structural changes over time. To address these issues, we introduce Spatio-Temporal Deep Graph ... More
Borel partitions of infinite subtrees of a perfect treeJan 15 1993A theorem of Galvin asserts that if the unordered pairs of reals are partitioned into finitely many Borel classes then there is a perfect set P such that all pairs from P lie in the same class. The generalization to n-tuples for n >= 3 is false. Let us ... More
Topological complexity of a fibrationSep 24 2018We study certain topological problems that are inspired by applications to autonomous robot manipulation. Consider a continuous map $f\colon X\to Y$, where $f$ can be a kinematic map from the configuration space $X$ to the working space $Y$ of a robot ... More
Economic impact of IoT cyber risk - Analysing past and present to predict the future developments in IoT risk analysis and IoT cyber insuranceOct 13 2018This paper is focused on mapping the current evolution of Internet of Things (IoT) and its associated cyber risks for the Industry 4.0 (I4.0) sector. We report the results of a qualitative empirical study that correlates academic literature with 14 - ... More
Convergent measure of focal extent, and largest peak intensity for non-paraxial beamsApr 26 2018Jun 06 2018Second moment beam widths are commonly used in paraxial optics to define the focal extent of beams. However, second moments of arbitrary beams are not guaranteed to be finite. I propose the focal concentration area as a measure of beam focal area, defined ... More
Norm of the Bergman projection onto the Bloch space with $\mathcal{M}-$invariant gradientNov 23 2017May 18 2018The value of the operator norm of Bergman projections from $L^{\infty}(\mathbb{B}^n)$ to Bloch space is found in \cite{KalajMarkovic2014}. The authors of mentioned paper proposed the problem of calculating the norm of the same class of operators with ... More
A proof of the Khavinson conjectureMar 11 2019\begin{abstract} This paper deals with an extremal problem for bounded harmonic functions in the unit ball $\mathbb{B}^n.$ We solve the Khavinson conjecture in $\mathbb{R}^3,$ an intriguing open question since 1992 posed by D. Khavinson, later considered ... More
Triangulations with few vertices of manifolds with non-free fundamental groupJan 15 2018We study lower bounds for the number of vertices in a PL-triangulation of a given manifold $M$. While most of the previous estimates are based on the dimension and the connectivity of $M$, we show that further information can be extracted by studying ... More
Koji: Automating pipelines with mixed-semantics data sourcesDec 02 2018We propose a new result-oriented semantic for defining data processing workflows that manipulate data in different semantic forms (files or services) in a unified manner. This approach enables users to define workflows for a vast variety of reproducible ... More
On the norm of the weighted Berezin transformNov 13 2017Jan 23 2018We consider a weighted Berezin transform: $$ B_{\alpha} : L^{\infty} (\mathbb{B}^n) \to \ \mathcal{B},\quad \alpha>-1,$$ defined, for $f \in L^{\infty} \left( \mathbb{B}^n \right)$ and $z \in \mathbb{B}^n$, by $$(B_\alpha f) (z) = c_\alpha \int_{\mathbb{B}^n} ... More
Theta lifts of generic representations for dual pairs $(\mathrm{Sp}_{2n}, \mathrm{O}(V))$Nov 10 2018We determine the occurrence and explicitly describe the theta lifts on all levels of all the irreducible generic representations for the dual pair of groups $(\mathrm{Sp}_{2n}, \mathrm{O}(V))$ defined over a local nonarchimedean field $\mathbb{F}$ of ... More
A proof of the Khavinson conjectureMar 11 2019Mar 27 2019\begin{abstract} This paper deals with an extremal problem for bounded harmonic functions in the unit ball $\mathbb{B}^n.$ We solve the Khavinson conjecture in $\mathbb{R}^3,$ an intriguing open question since 1992 posed by D. Khavinson, later considered ... More
A note on mean-value properties of harmonic functions on the hypercubeJun 16 2015Aug 20 2015For functions defined on the $n$-dimensional hypercube $I_n (r) = \{{\bm{x}} \in \mathbb{R}^n ~\vert~ \vert x_i \vert \le r,~ i = 1, 2, \ldots , n\}$ and harmonic therein, we establish certain analogues of Gauss surface and volume mean-value formulas ... More
Complexity of the forward kinematic mapAug 02 2017The main objective of this paper is to introduce a new method for qualitative analysis of various designs of robot arms. To this end we define the complexity of a map, examine its main properties and develop some methods of computation. In particular, ... More
A Transposition Rule Analysis Based on a Particle ProcessApr 02 2004Jun 12 2005A linear list is a collection of items that can be accessed sequentially. The cost of a request is the number of items that need to be examined before the desired item is located, i.e., the distance of the requested item from the beginning of the list. ... More
Subspace acceleration for large-scale parameter-dependent Hermitian eigenproblemsApr 23 2015This work is concerned with approximating the smallest eigenvalue of a parameter-dependent Hermitian matrix $A(\mu)$ for many parameter values $\mu \in \mathbb{R}^P$. The design of reliable and efficient algorithms for addressing this task is of importance ... More
Some epistemic questions of cosmologySep 20 2007We discuss a number of fundamental aspects of modern cosmological concepts, from the phenomenological, observational, theoretical and epistemic points of view. We argue that the modern cosmology, despite a great advent, in particular in the observational ... More
ALOHA Random Access that Operates as a Rateless CodeAug 07 2013Various applications of wireless Machine-to-Machine (M2M) communications have rekindled the research interest in random access protocols, suitable to support a large number of connected devices. Slotted ALOHA and its derivatives represent a simple solution ... More
Protocol Coding through Reordering of User Resources: Applications and Capacity ResultsNov 26 2010Feb 01 2012While there are continuous efforts to introduce new communication systems and standards, it is legitimate to ask the question: how can one send additional bits by minimally changing the systems that are already operating? This is of a significant practical ... More
Zero-Error Capacity of a Class of Timing ChannelsNov 06 2013Aug 24 2014We analyze the problem of zero-error communication through timing channels that can be interpreted as discrete-time queues with bounded waiting times. The channel model includes the following assumptions: 1) Time is slotted, 2) at most $ N $ "particles" ... More
Start Making Sense: Semantic Plane Filtering and Control for Post-5G ConnectivityJan 18 2019This is a short position paper that introduces the concepts of semantic plane filtering and control for post-5G connectivity.
Cyclic cosmology in modified gravityJan 13 2017Jun 03 2017In this work we propose a new general model of eternal cyclic Universe. We start from the assumption that quantum gravity corrections can be effectively accounted by the addition of higher order curvature terms in the Lagrangian density for gravity. It ... More
Coded Slotted ALOHA with Varying Packet Loss Rate across UsersJun 29 2013The recent research has established an analogy between successive interference cancellation in slotted ALOHA framework and iterative belief-propagation erasure-decoding, which has opened the possibility to enhance random access protocols by utilizing ... More
Spaces with high topological complexityApr 23 2012Oct 23 2012By a formula of Farber the topological complexity TC(X) of a (p-1)-connected, m-dimensional CW-complex X is bounded above by (2m+1)/p+1. There are also various lower estimates for TC(X) such as the nilpotency of the ring $H^*(X\times X,\Delta(X))$, and ... More
Protocol Coding through Reordering of User Resources, Part I: Capacity ResultsFeb 01 2012The vast existing wireless infrastructure features a variety of systems and standards. It is of significant practical value to introduce new features and devices without changing the physical layer/hardware infrastructure, but upgrade it only in software. ... More
Lower bounds for topological complexityOct 31 2011Apr 20 2013We introduce fibrewise Whitehead- and fibrewise Ganea definitions of monoidal topological complexity. We then define several lower bounds for the topological complexity, which improve on the standard lower bound in terms of nilpotency of the cohomology ... More
Electric routing and concurrent flow cuttingSep 15 2009We investigate an oblivious routing scheme, amenable to distributed computation and resilient to graph changes, based on electrical flow. Our main technical contribution is a new rounding method which we use to obtain a bound on the L1->L1 operator norm ... More
Parking functions and tree inversions revisitedJun 10 2015Feb 02 2016Kreweras proved that the reversed sum enumerator for parking functions of length $n$ is equal to the inversion enumerator for labeled trees on $n+1$ vertices. Recently, Perkinson, Yang, and Yu gave a bijective proof of this equality that moreover generalizes ... More
Bethe-Salpeter approach to the collective-mode spectrum of a superfluid Fermi gas in a moving optical latticeMar 10 2011We have derived the Bethe-Salpeter (BS) equations for the collective-mode spectrum of a mixture of fermion atoms of two hyperfine states loaded into a moving optical lattice. The collective excitation spectrum exhibits rotonlike minimum and the Landau ... More
Compressed sensing MRI using masked DCT and DFT measurementsMar 25 2015This paper presents modification of the TwIST algorithm for Compressive Sensing MRI images reconstruction. Compressive Sensing is new approach in signal processing whose basic idea is recovering signal form small set of available samples. The application ... More
A Bayesian Approach to Data Fusion in Sensor NetworksMar 11 2013Sep 11 2015In this paper, we address the fusion problem in wireless sensor networks, where the cross-correlation between the estimates is unknown. To solve the problem within the Bayesian framework, we assume that the covariance matrix has a prior distribution. ... More
GRB afterglow light curves from realistic density profilesJun 09 2011The afterglow emission that follows gamma-ray bursts (GRBs) contains valuable information about the circumburst medium and, therefore, about the GRB progenitor. Theoretical studies of GRB blast waves, however, are often limited to simple density profiles ... More
Physical Network Coding in Two-Way Wireless Relay ChannelsJul 03 2007It has recently been recognized that the wireless networks represent a fertile ground for devising communication modes based on network coding. A particularly suitable application of the network coding arises for the two--way relay channels, where two ... More
Steady-state analysis of a multi-server queue in the Halfin-Whitt regimeOct 02 2007Mar 18 2008We consider a multi-server queue in the Halfin-Whitt regime: as the number of servers $n$ grows without a bound, the utilization approaches 1 from below at the rate $\Theta(1/\sqrt{n})$. Assuming that the service time distribution is lattice-valued with ... More
SU(3)-instantons and $G_2, Spin(7)$-heterotic string solitonsDec 03 2003Feb 24 2005Necessary and sufficient conditions to the existence of a hermitian connection with totally skew-symmetric torsion and holonomy contained in SU(3) are given. Non-compact solution to the supergravity-type I equations of motion with non-zero flux and non-constant ... More
Information carrying capacity of a cosmological constantAug 19 2016Jan 05 2017We analyze the exchange of information in different cosmological backgrounds when sender and receiver are timelike separated and communicate through massless fields (without the exchange of light-signals). Remarkably, we show that the dominance of a cosmological ... More
Reliable Reception of Wireless Metering Data with Protocol CodingMay 21 2013Stationary collectors reading wireless, battery powered smart meters, often operate in harsh channel conditions to cut network installation cost to a minimum, challenging the individual link to each meter. The desired performance measure is reliable reception ... More
Low-Rate Machine-Type Communication via Wireless Device-to-Device (D2D) LinksMay 29 2013Wireless cellular networks feature two emerging technological trends. The first is the direct Device-to-Device (D2D) communications, which enables direct links between the wireless devices that reutilize the cellular spectrum and radio interface. The ... More
Reliable Uplink Communication through Double Association in Wireless Heterogeneous NetworksMay 08 2015Apr 03 2016We investigate methods for network association that improve the reliability of uplink transmissions in dense wireless heterogeneous networks. The stochastic geometry analysis shows that the double association, in which an uplink transmission is transmitted ... More
Non-perturbative analysis of entanglement harvesting from coherent field statesJun 30 2017We study (non-perturbatively) the interactions of delta-coupled detectors with coherent states of a scalar field. We show that the time-evolved density matrix spectra of i) a single detector, ii) two detectors, and iii) the partial transpose of the latter, ... More
Casualty Detection from 3D Point Cloud Data for Autonomous Ground Mobile Rescue RobotsDec 21 2018One of the most important features of mobile rescue robots is the ability to autonomously detect casualties, i.e. human bodies, which are usually lying on the ground. This paper proposes a novel method for autonomously detecting casualties lying on the ... More
Zero-Outage Cellular Downlink with Fixed-Rate D2D UnderlayApr 28 2014Dec 30 2014Two of the emerging trends in wireless cellular systems are Device-to-Device (D2D) and Machine-to-Machine (M2M) communications. D2D enables efficient reuse of the licensed spectrum to support localized transmissions, while M2M connections are often characterized ... More
The information carrying capacity of a cosmological constantAug 19 2016We analyze the exchange of information in different cosmological backgrounds when sender and receiver are timelike separated and communicate through massless fields (without the exchange of light-signals). Remarkably, we show that the dominance of a cosmological ... More
Minimizing the Age of Information from Sensors with Correlated ObservationsNov 15 2018The Age of Information (AoI) metric has recently received much attention as a measure of freshness of information in a network. In this paper, we study the average AoI in a generic setting with correlated sensor information, which can be related to multiple ... More
Block-Fading Channels with Delayed CSIT at Finite BlocklengthJan 28 2014In many wireless systems, the channel state information at the transmitter (CSIT) can not be learned until after a transmission has taken place and is thereby outdated. In this paper, we study the benefits of delayed CSIT on a block-fading channel at ... More
All coherent field states entangle equallyMay 11 2017We analyze the interactions of particle detectors with coherent states of a free scalar field. We find that the eigenvalues of the post-interaction density matrices of i) a single detector, ii) two detectors, and iii) the partial transpose of the latter, ... More
Harvesting correlations from thermal and squeezed coherent statesSep 14 2018We study the harvesting of entanglement and mutual information by Unruh-DeWitt particle detectors from thermal and squeezed coherent field states. We prove (for arbitrary spatial dimensions, switching profiles and detector smearings) that while the entanglement ... More
Visuospatial Skill Learning for RobotsJun 03 2017A novel skill learning approach is proposed that allows a robot to acquire human-like visuospatial skills for object manipulation tasks. Visuospatial skills are attained by observing spatial relationships among objects through demonstrations. The proposed ... More
Sign-Compute-Resolve for Tree Splitting Random AccessFeb 08 2016We present an approach to random access that is based on three elements: physical-layer network coding (PLNC), signature codes and tree splitting. In presence of a collision, physical-layer network coding enables the receiver to decode, i.e. compute the ... More
Adapting the Number of Particles in Sequential Monte Carlo Methods through an Online Scheme for Convergence AssessmentSep 16 2015Particle filters are broadly used to approximate posterior distributions of hidden states in state-space models by means of sets of weighted particles. While the convergence of the filter is guaranteed when the number of particles tends to infinity, the ... More
Q-map: a Convolutional Approach for Goal-Oriented Reinforcement LearningOct 06 2018Goal-oriented learning has become a core concept in reinforcement learning (RL), extending the reward signal as a sole way to define tasks. However, as parameterizing value functions with goals increases the learning complexity, efficiently reusing past ... More
Action Branching Architectures for Deep Reinforcement LearningNov 24 2017Jan 25 2019Discrete-action algorithms have been central to numerous recent successes of deep reinforcement learning. However, applying these algorithms to high-dimensional action tasks requires tackling the combinatorial increase of the number of possible actions ... More
Optimized Interface Diversity for Ultra-Reliable Low Latency Communication (URLLC)Dec 14 2017An important ingredient of the future 5G systems will be Ultra-Reliable Low-Latency Communication (URLLC). A way to offer URLLC without intervention in the baseband/PHY layer design is to use \emph{interface diversity} and integrate multiple communication ... More
Multikast rutiranje open-source platformom - XORPDec 03 2017Integration of a software router into embedded systems is obtained possibility of the most modern routers, at a much more affordable price. Transfer services TV and radio signals over the IP network are only activated by using multicast 1 protocol for ... More
Reliable and Efficient Access for Alarm-initiated and Regular M2M Traffic in IEEE 802.11ah SystemsJun 29 2017EEE 802.11ah is a novel WiFi-based protocol, aiming to provide an access solution for the machine-to-machine (M2M) communications. In this paper, we propose an adaptive access mechanism that can be seamlessly incorporated into IEEE 802.11ah protocol operation ... More
Chiral Magnetohydrodynamic TurbulenceDec 21 2016Sep 10 2017In this work the influence of the chiral anomaly effect on the evolution of magnetohydrodynamic turbulence was studied. We argue that in the early universe, before the electroweak symmetry breaking, and for temperatures high enough such that the electron ... More
Power Talk for Multibus DC MicroGrids: Creating and Optimizing Communication ChannelsSep 26 2016We study a communication framework for nonlinear multibus DC MicroGrids based on a deliberate modification of the parameters of the primary control and termed power talk. We assess the case in which the information is modulated in the deviations of reference ... More
Decoupled Uplink and Downlink in a Wireless System with Buffer-Aided RelayingSep 21 2016Sep 22 2016The paper treats a multiuser relay scenario where multiple user equipments (UEs) have a two-way communication with a common Base Station (BS) in the presence of a buffer-equipped Relay Station (RS). Each of the uplink (UL) and downlink (DL) transmission ... More
Modified Magnetohydrodynamics Around the Electroweak TransitionFeb 26 2016Jul 13 2016We analyse solutions of the MHD equations around the electroweak transition taking into account the effects of the chiral anomaly. It is shown that a transition that is not of the first order has direct consequences on the evolution of the asymmetry between ... More
Sign-Compute-Resolve for Tree Splitting Random AccessFeb 08 2016May 16 2018We present a framework for random access that is based on three elements: physical-layer network coding (PLNC), signature codes and tree splitting. In presence of a collision, physical-layer network coding enables the receiver to decode, i.e. compute, ... More
Communications with decode-and-forward relays in mesh networksOct 16 2012We consider mesh networks composed of groups of relaying nodes which operate in decode-and-forward mode, where each node from a group relays information to all the nodes in the next group. We study these networks in two setups, one where the nodes have ... More
Adapting the Number of Particles in Sequential Monte Carlo Methods through an Online Scheme for Convergence AssessmentSep 16 2015Oct 31 2017Particle filters are broadly used to approximate posterior distributions of hidden states in state-space models by means of sets of weighted particles. While the convergence of the filter is guaranteed when the number of particles tends to infinity, the ... More
An RMHD study of transition between prompt and afterglow GRB phasesJan 09 2008We study the afterglow phases of a GRB through relativistic magnetohydrodynamic simulations. The evolution of a relativistic shell propagating into a homogeneous external medium is followed. We focus on the effect of the magnetization of the ejecta on ... More
Geodesic equivalence and integrabilityNov 10 1999We suggest a construction that, given a trajectorial diffeomorphism between two Hamiltonian systems, produces integrals of them. As the main example we treat geodesic equivalence of metrics. We show that the existence of a non-trivially geodesically equivalent ... More
Farey sequence in the appearance of subharmonic Shapiro stepsJan 12 2015Apr 24 2015Largest Lyapunov exponent has been examined in the dynamical-mode locking phenomena of the ac+dc driven dissipative Frenkel-Kontorova model with deformable substrate potential. Due to deformation, large fractional and higher order subharmonic steps appear ... More
Geometry of compact lifting spacesJan 07 2019We study a natural generalization of inverse systems of finite regular covering spaces. A limit of such a system is a fibration whose fibres are profinite topological groups. However, as shown in a previous paper (Conner-Herfort-Pavesic: Some anomalous ... More
Dynamical and Topological methods in Theory of Geodesically Equivalent MetricsNov 09 1999This paper is a review on recently found connection between geodesically equivalent metrics and integrable geodesic flows. Suppose two different metrics on one manifold have the same geodesics. We show that then the geodesic flows of these metrics admit ... More
Some anomalous examples of lifting spacesAug 02 2017An inverse limit of a sequence of covering spaces over a given space $X$ is not, in general, a covering space over $X$ but is still a lifting space, i.e. a Hurewicz fibration with unique path lifting property. Of particular interest are inverse limits ... More
Frameless ALOHA Protocol for Wireless NetworksMay 18 2012Oct 10 2012We propose a novel distributed random access scheme for wireless networks based on slotted ALOHA, motivated by the analogies between successive interference cancellation and iterative belief-propagation decoding on erasure channels. The proposed scheme ... More
Elusive structure of helium trimersJul 20 2016Over the years many He-He interaction potentials have been developed, some very sophisticated, including various corrections beyond Born-Oppenheimer approximation. Most of them were used to predict properties of helium dimers and trimers, examples of ... More
Goal-oriented Trajectories for Efficient ExplorationJul 05 2018Exploration is a difficult challenge in reinforcement learning and even recent state-of-the art curiosity-based methods rely on the simple epsilon-greedy strategy to generate novelty. We argue that pure random walks do not succeed to properly expand the ... More
Coexistence of URLLC and eMBB services in the C-RAN Uplink: An Information-Theoretic StudyApr 18 2018The performance of orthogonal and non-orthogonal multiple access is studied for the multiplexing of enhanced Mobile BroadBand (eMBB) and Ultra-Reliable Low-Latency Communications (URLLC) users in the uplink of a multi-cell Cloud Radio Access Network (C-RAN) ... More
Modeling the Spread of Multiple Contagions on Multilayer NetworksMar 08 2017Jul 21 2017A susceptible-infected-susceptible (SIS) model of multiple contagions on multilayer networks is developed to incorporate different spreading channels and disease mutations. The basic reproduction number for this model is estimated analytically. In a special ... More
On Buffer-Aided Multiple-Access Relay ChannelSep 21 2016Sep 22 2016The paper treats uplink scenario where M user equipments (UEs) send to a Base Station (BS), possibly via a common Relay Station (RS) that is equipped with a buffer. This is a multiple-access relay channel (MARC) aided by a buffer. We devise a protocol ... More
Access Control Synthesis for Physical SpacesMay 05 2016Access-control requirements for physical spaces, like office buildings and airports, are best formulated from a global viewpoint in terms of system-wide requirements. For example, "there is an authorized path to exit the building from every room." In ... More
5G Ultra-Reliable Vehicular CommunicationOct 05 2015Oct 08 2015Applications enabled by Cooperative Intelligent Transport Systems (C-ITS) represent a major step towards making the road transport system safer and more efficient (green), and thus suited for a sustainable future. Wireless communication between vehicles ... More
Towards Massive, Ultra-Reliable, and Low-Latency Wireless Communication with Short PacketsApr 24 2015Mar 01 2016Most of the recent advances in the design of high-speed wireless systems are based on information-theoretic principles that demonstrate how to efficiently transmit long data packets. However, the upcoming wireless systems, notably the 5G system, will ... More
Scotogenic R\nuMDM at Three-Loop LevelFeb 27 2015Mar 30 2015We propose a model in which the radiative neutrino (R\nu) masses are induced by fermion quintuplet and scalar septuplet fields from the minimal-dark-matter (MDM) setup. In conjunction with the 2HDM fields, on top of which our model is built, these hypercharge ... More
Physical Layer Network Coding: A Cautionary Story with Interference and Spatial ReservationNov 06 2013Physical layer network coding (PLNC) has the potential to improve throughput of multi-hop networks. However, most of the works are focused on the simple, three-node model with two-way relaying, not taking into account the fact that there can be other ... More
Afterglow Model for the Radio Emission from the Jetted Tidal Disruption Candidate Swift J1644+57Oct 05 2011Jun 12 2012The recent transient event Swift J1644+57 has been interpreted as emission from a collimated relativistic jet, powered by the sudden onset of accretion onto a supermassive black hole following the tidal disruption of a star. Here we model the radio-microwave ... More
INFRAWEBS axiom editor - a graphical ontology-driven tool for creating complex logical expressionsApr 02 2009Jan 07 2012The current INFRAWEBS European research project aims at developing ICT framework enabling software and service providers to generate and establish open and extensible development platforms for Web Service applications. One of the concrete project objectives ... More
Using Wireless Network Coding to Replace a Wired with Wireless BackhaulApr 14 2014Cellular networks are evolving towards dense deployment of small cells. This in turn demands flexible and efficient backhauling solutions. A viable solution that reuses the same spectrum is wireless backhaul where the Small Base Station (SBS) acts as ... More
Minimizing Latency to Support VR Social Interactions over Wireless Cellular Systems via Bandwidth AllocationFeb 09 2018Apr 04 2018Immersive social interactions of mobile users are soon to be enabled within a virtual space, by means of virtual reality (VR) technologies and wireless cellular systems. In a VR mobile social network, the states of all interacting users should be updated ... More
Estimates of covering type and the number of vertices of minimal triangulationsOct 09 2017The covering type of a space $X$ is defined as the minimal cardinality of a good cover of a space that is homotopy equivalent to $X$. We derive estimates for the covering type of $X$ in terms of other invariants of $X$, namely the ranks of the homology ... More
Cognitive Access-Transmission Policies under a Primary ARQ process via Chain DecodingSep 26 2015This paper introduces a novel technique that enables access by a cognitive secondary user (SU) to a spectrum occupied by an incumbent primary user (PU) that employs Type-I Hybrid ARQ. The technique allows the SU to perform selective retransmissions of ... More
Efficient LTE Access with Collision Resolution for Massive M2M CommunicationsOct 24 2014LTE random access procedure performs satisfactorily in case of asynchronous, uncorrelated traffic arrivals. However, when the arrivals are correlated and arrive synchronously, the performance of the random access channel (RACH) is drastically reduced, ... More
Analysis of the Decoupled Access for Downlink and Uplink in Wireless Heterogeneous NetworksJul 02 2014Oct 21 2014Wireless cellular networks evolve towards a heterogeneous infrastructure, featuring multiple types of Base Stations (BSs), such as Femto BSs (FBSs) and Macro BSs (MBSs). A wireless device observes multiple points (BSs) through which it can access the ... More
Efficiency Analysis of Decoupled Downlink and Uplink Access in Heterogeneous NetworksDec 04 2014This paper analyzes two-tier heterogeneous cellular network with decoupled downlink and uplink access. The basic performance benefits of uplink/downlink decoupling have been recently introduced. Here we provide a more elaborate treatment of the decoupling ... More
Exploiting Capture Effect in Frameless ALOHA for Massive Wireless Random AccessJan 08 2014The analogies between successive interference cancellation (SIC) in slotted ALOHA framework and iterative belief-propagation erasure-decoding, established recently, enabled the application of the erasure-coding theory and tools to design random access ... More