Results for "Adib Mehrabi"

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A Note on Approximating 2-TransmittersDec 05 2015A k-transmitter in a simple orthogonal polygon P is a mobile guard that travels back and forth along an orthogonal line segment s inside P. The k-transmitter can see a point p in P if there exists a point q on s such that the line segment pq is normal ... More
Approximating Weighted Duo-Preservation in Comparative GenomicsAug 30 2017Motivated by comparative genomics, Chen et al. [9] introduced the Maximum Duo-preservation String Mapping (MDSM) problem in which we are given two strings $s_1$ and $s_2$ from the same alphabet and the goal is to find a mapping $\pi$ between them so as ... More
A Note on Approximating Weighted Independence on Intersection Graphs of Paths on a GridAug 30 2017Sep 06 2018A graph $G$ is called $B_k$-VPG, for some constant $k\geq 0$, if it has a string representation on an axis-parallel grid such that each vertex is a path with at most $k$ bends and two vertices are adjacent in $G$ if and only if the corresponding paths ... More
Similarity measures for vocal-based drum sample retrieval using deep convolutional auto-encodersFeb 14 2018The expressive nature of the voice provides a powerful medium for communicating sonic ideas, motivating recent research on methods for query by vocalisation. Meanwhile, deep learning methods have demonstrated state-of-the-art results for matching vocal ... More
Approximation Algorithms for Independence and Domination on B$_1$-VPG and B$_1$-EPG GraphsFeb 18 2017A graph $G$ is called B$_k$-VPG (resp., B$_k$-EPG), for some constant $k\geq 0$, if it has a string representation on a grid such that each vertex is an orthogonal path with at most $k$ bends and two vertices are adjacent in $G$ if and only if the corresponding ... More
Study Notes on Numerical Solutions of the Wave Equation with the Finite Difference MethodSep 22 2000Nov 19 2000In this introductory work I will present the Finite Difference method for hyperbolic equations, focusing on a method which has second order precision both in time and space (the so-called staggered leapfrog method) and applying it to the case of the 1d ... More
Stochastic actions for diffusive dynamics: Reweighting, sampling, and minimizationDec 10 2007In numerical studies of diffusive dynamics, two different action functionals are often used to specify the probability distribution of trajectories, one of which requiring the evaluation of the second derivative of the potential in addition to the force. ... More
Guarding the Vertices of an Orthogonal Terrain using Vertex GuardsDec 28 2015A terrain T is an x-monotone polygonal chain in the plane; T is orthogonal if each edge of T is either horizontal or vertical. In this paper, we give an exact algorithm for the problem of guarding the convex vertices of an orthogonal terrain with the ... More
Unique Set Cover on Unit Disks and Unit SquaresJul 25 2016We study the Unique Set Cover problem on unit disks and unit squares. For a given set $P$ of $n$ points and a set $D$ of $m$ geometric objects both in the plane, the objective of the Unique Set Cover problem is to select a subset $D'\subseteq D$ of objects ... More
Entropy and density of states from isoenergetic nonequilibrium processesAug 03 2004Apr 05 2005Two identities in statistical mechanics involving entropy differences (or ratios of density of states) at constant energy are derived. The first provides a nontrivial extension of the Jarzynski equality to the microcanonical ensemble [C. Jarzynski, Phys. ... More
Does the Boltzmann principle need a dynamical correction?Apr 27 2002Jun 10 2004In an attempt to derive thermodynamics from classical mechanics, an approximate expression for the equilibrium temperature of a finite system has been derived [M. Bianucci, R. Mannella, B. J. West, and P. Grigolini, Phys. Rev. E 51, 3002 (1995)] which ... More
NP-hardness of the cluster minimization problem revisitedSep 06 2005The computational complexity of the "cluster minimization problem" is revisited [L. T. Wille and J. Vennik, J. Phys. A 18, L419 (1985)]. It is argued that the original NP-hardness proof does not apply to pairwise potentials of physical interest, such ... More
Free energy surfaces from nonequilibrium processes without work measurementOct 24 2005Mar 01 2006Recent developments in statistical mechanics have allowed the estimation of equilibrium free energies from the statistics of work measurements during processes that drive the system out of equilibrium. Here a different class of processes is considered, ... More
Algorithms for Brownian first passage time estimationApr 27 2009A class of algorithms in discrete space and continuous time for Brownian first passage time estimation is considered. A simple algorithm is derived that yields exact mean first passage times (MFPT) for linear potentials in one dimension, regardless of ... More
Absolute Monte Carlo estimation of integrals and partition functionsJan 28 2010Owing to their favorable scaling with dimensionality, Monte Carlo (MC) methods have become the tool of choice for numerical integration across the quantitative sciences. Almost invariably, efficient MC integration schemes are strictly designed to compute ... More
Algebraic perturbation theory for dense liquids with discrete potentialsDec 28 2006A simple theory for the leading-order correction g_1(r) to the structure of a hard-sphere liquid with discrete (e.g. square-well) potential perturbations is proposed. The theory makes use of a general approximation that effectively eliminates four-particle ... More
Ergodicity and the Classical Lambda Phi^4 Lattice Field TheoryOct 15 2000In this talk we present some studies in the approach to equilibrium of the classical lambda phi^4 theory on the lattice, giving particular emphasis to its pedagogical usefulness in the context of classical statistical field theory (such as both the analytical ... More
Symmetry relations in chemical kinetics arising from microscopic reversibilitySep 08 2005Dec 06 2005It is shown that the kinetics of time-reversible chemical reactions having the same equilibrium constant but different initial conditions are closely related to one another by a directly measurable symmetry relation analogous to chemical detailed balance. ... More
(Non)existence of static scalar field configurations in finite systemsAug 22 2002Aug 28 2002Derrick's theorem on the nonexistence of stable time-independent scalar field configurations [G. H. Derrick, J. Math. Phys. 5, 1252 (1964)] is generalized to finite systems of arbitrary dimension. It is shown that the "dilation" argument underlying the ... More
Random walk approach to the d-dimensional disordered Lorentz gasNov 12 2007Feb 15 2008A correlated random walk approach to diffusion is applied to the disordered nonoverlapping Lorentz gas. By invoking the Lu-Torquato theory for chord-length distributions in random media [J. Chem. Phys. 98, 6472 (1993)], an analytic expression for the ... More
Comment on "On the Crooks fluctuation theorem and the Jarzynski equality" [J. Chem. Phys. 129, 091101 (2008)]Jul 10 2009It has recently been argued that a self-consistency condition involving the Jarzynski equality (JE) and the Crooks fluctuation theorem (CFT) is violated for a simple Brownian process [L. Y. Chen, J. Chem. Phys. 129, 091101 (2008)]. This note adopts the ... More
Adiabatic invariance with first integrals of motionMay 11 2002Oct 02 2002The construction of a microthermodynamic formalism for isolated systems based on the concept of adiabatic invariance is an old but seldom appreciated effort in the literature, dating back at least to P. Hertz [Ann. Phys. (Leipzig) 33, 225 (1910)]. An ... More
On Guarding Orthogonal Polygons with Bounded TreewidthJun 07 2017There exist many variants of guarding an orthogonal polygon in an orthogonal fashion: sometimes a guard can see an entire rectangle, or along a staircase, or along an orthogonal path with at most $k$ bends. In this paper, we study all these guarding models ... More
Grid-Obstacle Representations with Connections to Staircase GuardingAug 06 2017Aug 29 2017In this paper, we study grid-obstacle representations of graphs where we assign grid-points to vertices and define obstacles such that an edge exists if and only if an $xy$-monotone grid path connects the two endpoints without hitting an obstacle or another ... More
Constrained Orthogonal Segment StabbingApr 30 2019Let $S$ and $D$ each be a set of orthogonal line segments in the plane. A line segment $s\in S$ \emph{stabs} a line segment $s'\in D$ if $s\cap s'\neq\emptyset$. It is known that the problem of stabbing the line segments in $D$ with the minimum number ... More
Studying wave optics in the light curve of exoplanet microlensingJul 17 2012Mar 13 2013We study the wave optics features of gravitational microlensing by a binary lens composed of a planet and a parent star. In this system, the source star near the caustic line produces a pair of images in which they can play the role of secondary sources ... More
On $r$-Guarding Thin Orthogonal PolygonsApr 25 2016Guarding a polygon with few guards is an old and well-studied problem in computational geometry. Here we consider the following variant: We assume that the polygon is orthogonal and thin in some sense, and we consider a point $p$ to guard a point $q$ ... More
Recursive constructions of k-normal polynomials over finite fieldsOct 15 2016The paper is devoted to produce infinite sequences of $k$-normal polynomials $F_{u}(x)\in \mathbb{F}_{q}[x]$ of degrees $np^{u} ~ (u\geq 0)$, for a suitably chosen initial $k$-normal polynomial $F_{0}(x)\in \mathbb{F}_{q}[x]$ of degree $n$ over $\mathbb{F}_{q}$ ... More
New Hardness Results for Guarding Orthogonal Polygons with Sliding CamerasMar 09 2013Let $P$ be an orthogonal polygon. Consider a sliding camera that travels back and forth along an orthogonal line segment $s\in P$ as its \emph{trajectory}. The camera can see a point $p\in P$ if there exists a point $q\in s$ such that $pq$ is a line segment ... More
Information gains from Monte Carlo Markov ChainsApr 26 2019In this paper, we present a novel method for computing the relative entropy as well as the expected relative entropy using an MCMC chain. The relative entropy from information theory can be used to quantify differences in posterior distributions of a ... More
Unbiased estimators for spatial distribution functions of classical fluidsOct 14 2004We use a statistical-mechanical identity closely related to the familiar virial theorem, to derive unbiased estimators for spatial distribution functions of classical fluids. In particular, we obtain estimators for both the fluid density rho(r) in the ... More
A new family of one-coincidence sets of sequences with dispersed elements for frequency hopping CDMA systemsJan 18 2017Dec 08 2017We present a new family of one-coincidence sequence sets suitable for frequency hopping code division multiple access (FH-CDMA) systems with dispersed (low density) sequence elements. These sets are derived from one-coincidence prime sequence sets, such ... More
A (7/2)-Approximation Algorithm for Guarding Orthogonal Art Galleries with Sliding CamerasAug 13 2013Sep 28 2013Consider a sliding camera that travels back and forth along an orthogonal line segment $s$ inside an orthogonal polygon $P$ with $n$ vertices. The camera can see a point $p$ inside $P$ if and only if there exists a line segment containing $p$ that crosses ... More
Network Selection Decision Based on Handover History in Heterogeneous Wireless NetworksJun 07 2012In recent years, the mobile devices are equipped with several wireless interfaces in heterogeneous environments which integrate a multitude of radio access technologies (RAT's). The evolution of these technologies will allow the users to benefit simultaneously ... More
Kink Dynamics in a Topological Phi^4 LatticeApr 26 2001Jun 20 2001It was recently proposed a novel discretization for nonlinear Klein-Gordon field theories in which the resulting lattice preserves the topological (Bogomol'nyi) lower bound on the kink energy and, as a consequence, has no Peierls-Nabarro barrier even ... More
Path integral analysis of Jarzynski's equality: Analytical resultsNov 29 2008We apply path integrals to study nonequilibrium work theorems in the context of Brownian dynamics, deriving in particular the equations of motion governing the most typical and most dominant trajectories. For the analytically soluble cases of a moving ... More
Joint Optimization of QoE and Fairness Through Network Assisted Adaptive Mobile Video StreamingAug 09 2017MPEG has recently proposed Server and Network Assisted Dynamic Adaptive Streaming over HTTP (SAND-DASH) for video streaming over the Internet. In contrast to the purely client-based video streaming in which each client makes its own decision to adjust ... More
An Intelligent Network Selection Strategy Based on MADM Methods in Heterogeneous NetworksApr 06 2012Providing service continuity to the end users with best quality is a very important issue in the next generation wireless communications. With the evolution of the mobile devices towards a multimode architecture and the coexistence of multitude of radio ... More
Optimized free energies from bidirectional single-molecule force spectroscopyFeb 02 2008Apr 10 2008An optimized method for estimating path-ensemble averages using data from processes driven in opposite directions is presented. Based on this estimator, bidirectional expressions for reconstructing free energies and potentials of mean force from single-molecule ... More
An Enhanced Evaluation Model For Vertical Handover Algorithm In Heterogeneous NetworksJun 08 2012The vertical handover decision is considered an NP-Hard problem. For that reason, a large variety of vertical handoff algorithms (VHA) have been proposed to help the user to select dynamically the best access network in terms of quality of service (QoS). ... More
Can observational growth rate data favour the clustering dark energy models?Nov 04 2014Under the commonly used assumption that clumped objects can be well described by a spherical top-hat matter density profile, we investigate the evolution of the cosmic growth index in clustering dark energy (CDE) scenarios on sub-horizon scales. We show ... More
Compact object detection in self-lensing binary systems with a main-sequence starAug 05 2010Detecting compact objects by means of their gravitational lensing effect on an observed companion in a binary system has already been suggested almost four decades ago. However, these predictions were made even before the first observations of gravitational ... More
Tachyon warm-intermediate inflation in the light of Planck dataApr 19 2016Sep 17 2016We study the main properties of the warm inflationary model based on Barrow's solution for the scale factor of the universe. Within this framework we calculate analytically the basic slow roll parameters for different versions of warm inflation. We test ... More
On the possibility of magnetic field detection on a microlensed source starAug 01 2015In a microlensing event, a large magnification occurs at caustic crossing and provides an opportunity to obtain a stronger signal associated with the object. In this paper we study the possibility of magnetic field detection in a microlensing event through ... More
Bounds on the Approximation Power of Feedforward Neural NetworksJun 29 2018The approximation power of general feedforward neural networks with piecewise linear activation functions is investigated. First, lower bounds on the size of a network are established in terms of the approximation error and network depth and width. These ... More
Cache-Aware QoE-Traffic Optimization in Mobile Edge Assisted Adaptive Video StreamingMay 19 2018Multi-access edge computing (MEC) enables placing video content at the edge of the network aiming to improve the quality of experience (QoE) of the mobile clients. Video content caching at edge servers also reduces traffic in the backhaul of the mobile ... More
How clustering dark energy affects matter perturbationsApr 06 2015Aug 01 2015The rate of structure formation in the Universe is different in homogeneous and clustered dark energy models. The degree of dark energy clustering depends on the magnitude of its effective sound speed $c^{2}_{\rm eff}$ and for $c_{\rm eff}=0$ dark energy ... More
Gauge-QuintessenceOct 03 2015In this work, we introduce a new quintessence model associated with non-Abelian gauge fields, minimally coupled to Einstein gravity. This gauge theory has been originally introduced and studied as an inflationary model, called gauge-flation. Here, however, ... More
Measuring the effects of Loop Quantum Cosmology in the CMB dataMay 16 2017In this Essay we investigate the observational signatures of Loop Quantum Cosmology (LQC) in the CMB data. First, we concentrate on the dynamics of LQC and we provide the basic cosmological functions. We then obtain the power spectrum of scalar and tensor ... More
Sliding k-Transmitters: Hardness and ApproximationJul 25 2016A sliding k-transmitter in an orthogonal polygon P is a mobile guard that travels back and forth along an orthogonal line segment s inside P. It can see a point p in P if the perpendicular from p onto s intersects the boundary of P at most k times. We ... More
Graphettes: Constant-time determination of graphlet and orbit identity including (possibly disconnected) graphlets up to size 8Aug 14 2017Graphlets are small connected induced subgraphs of a larger graph $G$. Graphlets are now commonly used to quantify local and global topology of networks in the field. Methods exist to exhaustively enumerate all graphlets (and their orbits) in large networks ... More
Tachyon warm inflation with the effects of Loop Quantum Cosmology in the light of Planck 2015Mar 04 2017Jan 14 2018We investigate the observational signatures of quantum cosmology in the Cosmic Microwave Background data provided by Planck collaboration. We apply the warm inflationary paradigm with a tachyon scalar field to the loop quantum cosmology. In this context, ... More
A Spatio-Temporal Multivariate Shared Component Model with an Application in Iran Cancer DataJul 19 2017Among the proposals for joint disease mapping, the shared component model has become more popular. Another recent advance to strengthen inference of disease data has been the extension of purely spatial models to include time and space-time interaction. ... More
Deep Learning Based Sphere DecodingJul 06 2018In this paper, a deep learning (DL)-based sphere decoding algorithm is proposed, where the radius of the decoding hypersphere is learnt by a deep neural network (DNN). The performance achieved by the proposed algorithm is very close to the optimal maximum ... More
The vertex-isoperimetric number of the incidence andnon-incidence graphs of unitalsDec 06 2017We derive upper and lower bounds for the vertex-isoperimetric number of the incidence graphs of unitals and determine its order of magnitude. In the case when a unital contains sufficiently large arcs, these bounds agree and give rise to the precise value ... More
Long-lived oscillons from asymmetric bubblesMar 07 2002Sep 11 2002The possibility that extremely long-lived, time-dependent, and localized field configurations (``oscillons'') arise during the collapse of asymmetrical bubbles in 2+1 dimensional phi^4 models is investigated. It is found that oscillons can develop from ... More
Constraints on shear and rotation with massive galaxy clustersAug 29 2016A precise determination of the mass function is an important tool to verify cosmological predictions of the $\Lambda$CDM model and to infer more precisely the better model describing the evolution of the Universe. Galaxy clusters have been currently used ... More
Evolution of heavy quark distribution function in quark-gluon plasma: using the Iterative Laplace Transform MethodJun 29 2015Jul 06 2015The "Iterative Laplace Transform Method" is used to solve the Fokker-Planck equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation ... More
Approximating Dominating Set on Intersection Graphs of Rectangles and L-framesMar 16 2018Jun 25 2018We consider the Minimum Dominating Set (MDS) problem on the intersection graphs of geometric objects. Even for simple and widely-used geometric objects such as rectangles, no sub-logarithmic approximation is known for the problem and (perhaps surprisingly) ... More
Constraints on shear and rotation with massive galaxy clustersAug 29 2016Nov 14 2016A precise determination of the mass function is an important tool to verify cosmological predictions of the $\Lambda$CDM model and to infer more precisely the better model describing the evolution of the Universe. Galaxy clusters have been currently used ... More
Generalized Ghost Dark Energy with Non-Linear InteractionNov 20 2016In this paper we investigate ghost dark energy model in the presence of non-linear interaction between dark energy and dark matter. The functional form of dark energy density in the generalized ghost dark energy (GGDE) model is $\rho_D\equiv f(H, H^2)$ ... More
Agegraphic dark energy: growth index and cosmological implicationsAug 31 2016Sep 21 2016We study the main cosmological properties of the agegraphic dark energy model at the expansion and perturbation levels. Initially, using the latest cosmological data we implement a joint likelihood analysis in order to constrain the cosmological parameters. ... More
Debiasing Community Detection: The Importance of Lowly-Connected NodesMar 19 2019Community detection is an important task in social network analysis, allowing us to identify and understand the communities within the social structures. However, many community detection approaches either fail to assign low degree (or lowly-connected) ... More
On Unique Independence Weighted GraphsJul 01 2009An independent set in a graph G is a set of vertices no two of which are joined by an edge. A vertex-weighted graph associates a weight with every vertex in the graph. A vertex-weighted graph G is called a unique independence vertex-weighted graph if ... More
Finding Pairwise Intersections Inside a Query RangeFeb 21 2015We study the following problem: preprocess a set O of objects into a data structure that allows us to efficiently report all pairs of objects from O that intersect inside an axis-aligned query range Q. We present data structures of size $O(n({\rm polylog} ... More
Decision Directed Channel Estimation Based on Deep Neural Network k-step Predictor for MIMO Communications in 5GJan 11 2019We consider the use of deep neural network (DNN) to develop a decision-directed (DD)-channel estimation (CE) algorithm for multiple-input multiple-output (MIMO)-space-time block coded systems in highly dynamic vehicular environments. We propose the use ... More
Growth of matter perturbations in clustered holographic dark energy cosmologiesOct 14 2015Nov 17 2015We investigate the growth of matter fluctuations in holographic dark energy cosmologies. First we use an overall statistical analysis involving the latest observational data in order to place constraints on the cosmological parameters. Then we test the ... More
Profit-aware Online Vehicle-to-Grid Decentralized Scheduling under Multiple Charging StationsJul 23 2016Fluctuations in electricity tariffs induced by the sporadic nature of demand loads on power grids has initiated immense efforts to find optimal scheduling solutions for charging and discharging plug-in electric vehicles (PEVs) subject to different objective ... More
1-Bend RAC Drawings of 1-Planar GraphsAug 30 2016A graph is 1-planar if it has a drawing where each edge is crossed at most once. A drawing is RAC (Right Angle Crossing) if the edges cross only at right angles. The relationships between 1-planar graphs and RAC drawings have been partially studied in ... More
Interferometry for rotating sourcesAug 17 2015Jan 06 2016The two particle interferometry method to determine the size of the emitting source after a heavy ion collision is extended. Following the extension of the method to spherical expansion dynamics, here we extend the method to rotating systems. It is shown ... More
Evacuating Equilateral Triangles and Squares in the Face-to-Face ModelDec 25 2018Consider $k$ robots initially located at a point inside a region $T$. Each robot can move anywhere in $T$ independently of other robots with maximum speed one. The goal of the robots is to \emph{evacuate} $T$ through an exit at an unknown location on ... More
Profit-aware Online Vehicle-to-Grid Decentralized Scheduling under Multiple Charging StationsJul 23 2016Dec 26 2018Fluctuations in electricity tariffs induced by the sporadic nature of demand loads on power grids has initiated immense efforts to find optimal scheduling solutions for charging and discharging plug-in electric vehicles (PEVs) subject to different objective ... More
Drawing HV-Restricted Planar GraphsApr 14 2019A strict orthogonal drawing of a graph $G=(V, E)$ in $\mathbb{R}^2$ is a drawing of $G$ such that each vertex is mapped to a distinct point and each edge is mapped to a horizontal or vertical line segment. A graph $G$ is $HV$-restricted if each of its ... More
Reduction of phonon mean free path: from low temperature physics to room temperature applications in thermoelectricityDec 14 2016It has been proposed for a long time now that the reduction of the thermal conductivity by reducing the phonon mean free path is one of the best way to improve the current performance of thermoelectrics. By measuring the thermal conductance and thermal ... More
Tsallis thermostatistics for finite systems: a Hamiltonian approachApr 01 2002Aug 14 2002We show that finite systems whose Hamiltonians obey a generalized homogeneity relation rigorously follow the nonextensive thermostatistics of Tsallis. In the thermodynamical limit, however, our results indicate that the Boltzmann-Gibbs statistics is always ... More
Minimum Perimeter-Sum Partitions in the PlaneMar 16 2017Let $P$ be a set of $n$ points in the plane. We consider the problem of partitioning $P$ into two subsets $P_1$ and $P_2$ such that the sum of the perimeters of $\text{CH}(P_1)$ and $\text{CH}(P_2)$ is minimized, where $\text{CH}(P_i)$ denotes the convex ... More
On the Minimum Consistent Subset ProblemOct 22 2018Nov 26 2018Let $P$ be a set of $n$ colored points in the plane. Introduced by Hart (1968), a consistent subset of $P$, is a set $S\subseteq P$ such that for every point $p$ in $P\setminus S$, the closest point of $p$ in $S$ has the same color as $p$. The consistent ... More
RTL-PSC: Automated Power Side-Channel Leakage Assessment at Register-Transfer LevelJan 17 2019Power side-channel attacks (SCAs) have become a major concern to the security community due to their non-invasive feature, low-cost, and effectiveness in extracting secret information from hardware implementation of cryto algorithms. Therefore, it is ... More
Boundary Labeling for Rectangular DiagramsMar 28 2018Given a set of $n$ points (sites) inside a rectangle $R$ and $n$ points (label locations or ports) on its boundary, a boundary labeling problem seeks ways of connecting every site to a distinct port while achieving different labeling aesthetics. We examine ... More
Cooperative Abnormality Detection via Diffusive Molecular CommunicationsMar 29 2017In this paper, we consider abnormality detection via diffusive molecular communications (MCs) for a network consisting of several sensors and a fusion center (FC). If a sensor detects an abnormality, it injects into the medium a number of molecules which ... More
Constraints to dark energy using PADE parameterisationsJun 07 2017We put constraints on dark energy properties using the PADE parameterisation, and compare it to the same constraints using Chevalier-Polarski-Linder (CPL) and $\Lambda$CDM, at both the background and the perturbation levels. The dark energy equation of ... More
DynamicGEM: A Library for Dynamic Graph Embedding MethodsNov 26 2018DynamicGEM is an open-source Python library for learning node representations of dynamic graphs. It consists of state-of-the-art algorithms for defining embeddings of nodes whose connections evolve over time. The library also contains the evaluation framework ... More
On Guarding Orthogonal Polygons with Sliding CamerasApr 25 2016A sliding camera inside an orthogonal polygon $P$ is a point guard that travels back and forth along an orthogonal line segment $\gamma$ in $P$. The sliding camera $g$ can see a point $p$ in $P$ if the perpendicular from $p$ onto $\gamma$ is inside $P$. ... More
Range-Clustering QueriesMay 17 2017In a geometric $k$-clustering problem the goal is to partition a set of points in $\mathbb{R}^d$ into $k$ subsets such that a certain cost function of the clustering is minimized. We present data structures for orthogonal range-clustering queries on a ... More
Polygon Simplification by Minimizing Convex CornersDec 13 2018Let $P$ be a polygon with $r>0$ reflex vertices and possibly with holes and islands. A subsuming polygon of $P$ is a polygon $P'$ such that $P \subseteq P'$, each connected component $R$ of $P$ is a subset of a distinct connected component $R'$ of $P'$, ... More
Approximability of Covering Cells with Line SegmentsSep 26 2018In COCOA 2015, Korman et al. studied the following geometric covering problem: given a set $S$ of $n$ line segments in the plane, find a minimum number of line segments such that every cell in the arrangement of the line segments is covered. Here, a line ... More
Computing Maximum Independent Set on Outerstring Graphs and Their RelativesMar 17 2019A graph $G$ with $n$ vertices is called an outerstring graph if it has an intersection representation of a set of $n$ curves inside a disk such that one endpoint of every curve is attached to the boundary of the disk. Given an outerstring graph representation, ... More
Activity Analyses for Solar-type Stars Observed with Kepler. II. Magnetic Feature Versus Flare ActivityMay 25 2017May 06 2018The light curves of solar-type stars present both periodic fluctuation and flare spikes. The gradual periodic fluctuation is interpreted as the rotational modulation of magnetic features on the stellar surface and is used to deduce magnetic feature activity ... More
Geodesic Obstacle Representation of GraphsMar 09 2018An obstacle representation of a graph is a mapping of the vertices onto points in the plane and a set of connected regions of the plane (called obstacles) such that the straight-line segment connecting the points corresponding to two vertices does not ... More
Ionic transport through sub-10 nm diameter hydrophobic high-aspect ratio nanopores: experiment, theory and simulationJun 11 2015Fundamental understanding of ionic transport at the nanoscale is essential for developing biosensors based on nanopore technology and new generation high-performance nanofiltration membranes for separation and purification applications. We study here ... More
Quantitative Histopathology of Stained Tissues using Color Spatial Light Interference Microscopy (cSLIM)Jun 10 2018Tissue biopsy evaluation in the clinic is in need of quantitative disease markers for diagnosis and, most importantly, prognosis. Among the new technologies, quantitative phase imaging (QPI) has demonstrated promise for histopathology because it reveals ... More
Magnetic activity analysis for a sample of G-type main sequence \emph{Kepler} targetsNov 22 2016The variation of a stellar light curve owing to the rotational modulation by the magnetic features (starspots and faculae) on the star's surface can be used to investigate the magnetic properties of the host star. In this paper, we use the periodicity ... More
Optimal Locally Repairable Codes with Improved Update ComplexityJun 30 2016Jul 14 2016For a systematic erasure code, update complexity (UC) is defined as the maximum number of parity blocks needed to be changed when some information blocks are updated. Locally repairable codes (LRCs) have been recently proposed and used in real-world distributed ... More
Hardware Trojan Detection through Information Flow Security VerificationMar 12 2018Semiconductor design houses are increasingly becoming dependent on third party vendors to procure intellectual property (IP) and meet time-to-market constraints. However, these third party IPs cannot be trusted as hardware Trojans can be maliciously inserted ... More
Improving Traffic Safety Through Video Analysis in Jakarta, IndonesiaNov 30 2018This project presents the results of a partnership between the Data Science for Social Good fellowship, Jakarta Smart City and Pulse Lab Jakarta to create a video analysis pipeline for the purpose of improving traffic safety in Jakarta. The pipeline transforms ... More
Wireless THz link with optoelectronic transmitter and receiverJan 10 2019Photonics might play a key role in future wireless communication systems that operate at THz carrier frequencies. A prime example is the generation of THz data streams by mixing optical signals in high-speed photodetectors. Over the previous years, this ... More