Results for "Wiktor Walasik"

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Phase transition in multimode nonlinear parity-time-symmetric waveguide couplersSep 11 2015Parity-time-symmetric ($\mathcal{PT}$-symmetric) optical waveguide couplers have become a key component for integrated optics. They offer new possibilities for fast, ultracompact, configurable, all-optical signal processing. Here, we study nonlinear properties ... More
Meta-$\mathcal{PT}$ Symmetry in Asymmetric Directional CouplersDec 21 2015Despite the benefits that directional coupler based parity-time symmetric systems may offer to the field of integrated optics, the realization of such couplers relies on rather strict design constraints on the waveguide parameters. Here, we investigate ... More
Nonlinear parity-time-symmetric transition in finite-size optical couplersSep 11 2015Parity-time-symmetric ($\mathcal{PT}$-symmetric) optical waveguide couplers offer a great potential for future applications in integrated optics. Studies of nonlinear $\mathcal{PT}$-symmetric couplers present new possibilities for ultracompact configurable ... More
Stationary plasmon-soliton waves in metal-dielectric nonlinear planar structures: modeling and propertiesNov 28 2013Dec 02 2013We present three complementary methods to study stationary nonlinear solutions in one-dimensional nonlinear metal-dielectric structures. Two of them use an approximate treatment of the Kerr type nonlinear term taking into account only the leading electric ... More
Supercharge optical arraysSep 15 2018Oct 06 2018We introduce the notion of a supercharge optical array synthesized according to supersymmetric charge operators. Starting from an arbitrary array, mathematical supersymmetry transformation can be used systematically to create a zero-energy physical state ... More
Reconfigurable Topological Photonic CrystalJun 16 2017Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topological order. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators are topologically ... More
Necklace Beam Generation in Nonlinear Colloidal Engineered MediaOct 21 2015Modulational instability is a phenomenon that reveals itself as the exponential growth of weak perturbations in the presence of an intense pump beam propagating in a nonlinear medium. It plays a key role in such nonlinear optical processes as supercontinuum ... More
Optically tunable topological photonic crystalJan 30 2019Topological photonic insulators pave the way toward efficient integrated photonic devices with minimized scattering losses. Optical properties of the majority of topological structures proposed to date are fixed by design such that no changes to their ... More
Continuous supersymmetric transformation for photonic designJan 25 2019We propose to use a continuous supersymmetric (SUSY) transformation of a dielectric permittivity profile in order to design a photonic mode sorter. The iso-spectrality of the SUSY transformation ensures that modes of the waveguide preserve their propagation ... More
Plasmon-soliton waves in planar slot waveguides: I. ModelingJun 24 2015Jun 29 2015We present two complementary models to study stationary nonlinear solutions in one-dimensional plasmonic slot waveguides made of a finite-thickness nonlinear dielectric core surrounded by metal regions. The considered nonlinearity is of focusing Kerr ... More
Dynamics of large femtosecond filament arrays: possibilities, limitations, and trade-offsDec 09 2015Stable propagation of large, multifilament arrays over long distances in air paves new ways for microwave-radiation manipulation. Although, the dynamics of a single or a few filaments was discussed in some of the previous studies, we show that the stability ... More
Symmetric metal slot waveguides with nonlinear dielectric core: bifurcations, size effects, and higher order modesMay 09 2014We study the nonlinear waves propagating in metal slot waveguides with a Kerr-type dielectric core. We develop two independent semi-analytical models to describe the properties of such waveguides. Using those models we compute the dispersion curves for ... More
Plasmon-soliton waves in planar slot waveguides: II. Results for stationary waves and stability analysisJun 26 2015Jun 29 2015We describe the results of the two methods we developed to calculate the stationary nonlinear solutions in one-dimensional plasmonic slot waveguides made of a finite-thickness nonlinear dielectric core surrounded by metal regions. These two methods are ... More
Modulation instability of structured-light beams in negative-index metamaterialsJan 13 2016Jan 15 2016One of the most fundamental properties of isotropic negative-index metamaterials, namely opposite directionality of the Poynting vector and the wavevector, enable many novel linear and nonlinear regimes of light-matter interactions. Here, we predict distinct ... More
Supersymmetry-guided method for mode selection and optimization in coupled systemsJun 05 2018Single-mode operation of coupled systems such as optical-fiber bundles, lattices of photonic waveguides, or laser arrays requires an efficient method to suppress unwanted super-modes. Here, we propose a systematic supersymmetry-based approach to selectively ... More
Trajectories and orbital angular momentum of necklace beams in nonlinear colloidal suspensionsMar 28 2017Recently, we have predicted that the modulation instability of optical vortex solitons propagating in nonlinear colloidal suspensions with exponential saturable nonlinearity leads to formation of necklace beams (NBs) [S.~Z.~Silahli, W.~Walasik and N.~M.~Litchinitser, ... More
Characterizations of some free random variables by properties of conditional moments of third degree polynomialsNov 18 2012We investigate Laha-Lukacs properties of noncommutative random variables (processes). We prove that some families of free Meixner distributions can be characterized by the conditional moments of polynomial functions of degree 3. We also show that this ... More
A Characterization of the Normal Distribution by the Independence of a Pair of Random VectorsJan 01 2016Kagan and Shalaevski 1967 have shown that if the random variables $X_1,\dots,X_n$ are independent and identically distributed and the distribution of $\sum_{i=1}^n(X_i+a_i)^2$ $a_i\in \mathbb{R}$ depends only on $\sum_{i=1}^na_i^2$ , then each $X_i$ follows ... More
Efficient coding of spectrotemporal binaural sounds leads to emergence of the auditory space representationNov 04 2013Feb 19 2014To date a number of studies have shown that receptive field shapes of early sensory neurons can be reproduced by optimizing coding efficiency of natural stimulus ensembles. A still unresolved question is whether the efficient coding hypothesis explains ... More
New characterization of two-state normal distributionJan 01 2014In this article we give a purely noncommutative criterion for the characterization of two-state normal distribution. We prove that families of two-state normal distribution can be described by relations which is similar to the conditional expectation ... More
On the structure of the set of bifurcation points of periodic solutions for multiparameter Hamiltonian systemsSep 28 2008This paper deals with periodic solutions of the Hamilton equation with many parameters. Theorems on global bifurcation of solutions with periods $2\pi/j,$ $j\in\mathbb{N},$ from a stationary point are proved. The Hessian matrix of the Hamiltonian at the ... More
Sparse, complex-valued representations of natural sounds learned with phase and amplitude continuity priorsDec 17 2013Feb 18 2014Complex-valued sparse coding is a data representation which employs a dictionary of two-dimensional subspaces, while imposing a sparse, factorial prior on complex amplitudes. When trained on a dataset of natural image patches, it learns phase invariant ... More
Orbital angular momentum beam instabilities in engineered nonlinear colloidal mediaSep 17 2017In this letter, we experimentally demonstrate the evolution of the optical vortex beams of different topological charges propagating in engineered nano-colloidal suspension of negative polarizability with saturable nonlinearities. Due to the high power ... More
Free-Space Nonlinear Beam Combining Towards FilamentationSep 02 2016Multi-filamentation opens new degrees of freedom for manipulating electromagnetic waves in air. However, without control, multiple filament interactions, including attraction, repulsion or fusion often result in formation of complex disordered filament ... More
Experimental demonstration of valley-Hall topological photonic crystal at telecommunication wavelengthsDec 20 2017May 18 2018Photonic topological insulators provide unprecedented possibilities to eliminate scattering losses and improve the efficiency of optical communication systems. Despite significant theoretical efforts, the experimental demonstration of an integrated photonic ... More
Linking de novo assembly results with long DNA reads by dnaasm-link applicationNov 13 2018Currently, third-generation sequencing techniques, which allow to obtain much longer DNA reads compared to the next-generation sequencing technologies, are becoming more and more popular. There are many possibilities to combine data from next-generation ... More
Natural statistics of binaural soundsFeb 19 2014Mar 01 2014Binaural sound localization is usually considered a discrimination task, where interaural time (ITD) and level (ILD) disparities at pure frequency channels are utilized to identify a position of a sound source. In natural conditions binaural circuits ... More
Sample Variance in Free ProbabilityJul 22 2016Aug 03 2016Let $X_1, X_2,\dots, X_n$ denote i.i.d.~centered standard normal random variables, then the law of the sample variance $Q_n=\sum_{i=1}^n(X_i-\bar{X})^2$ is the $\chi^2$-distribution with $n-1$ degrees of freedom. It is an open problem in classical probability ... More
Evaluation of Temporal Formulas Based on "Checking By Spheres"Feb 12 2017Classical algorithms of evaluation of temporal CTL formulas are constructed "bottom-up". A formula must be evaluated completely to give the result. In the paper, a new concept of "top-down" evaluation of temporal QsCTL (CTL with state quantifiers) formulas, ... More
Deadlock and Termination Detection using IMDS Formalism and Model Checking. Version 2Oct 24 2017Modern model checking techniques concentrate on global properties of verified systems, because the methods base on global state space. Local features like partial deadlock or process termination are not easy to express and check. In the paper a description ... More
Sample Variance in Free ProbabilityJul 22 2016Oct 21 2016Let $X_1, X_2,\dots, X_n$ denote i.i.d.~centered standard normal random variables, then the law of the sample variance $Q_n=\sum_{i=1}^n(X_i-\bar{X})^2$ is the $\chi^2$-distribution with $n-1$ degrees of freedom. It is an open problem in classical probability ... More
Timed Concurrent State MachinesOct 22 2017Timed Concurrent State Machines are an application of Alur's Timed Automata concept to coincidence-based (rather than interleaving) CSM modeling technique. TCSM support the idea of testing automata, allowing to specify time properties easier than temporal ... More
The weighted Singer conjecture for Coxeter groups in dimensions three and fourMar 09 2015Given a Coxeter system $(W,S)$ there is a contractible simplicial complex $\Sigma$ called the Davis complex on which $W$ acts properly and cocompactly. In an article of Dymara, the weighted $L^2$-(co)homology groups of $\Sigma$ were defined, and in an ... More
Supersymmetric microring laser arraysFeb 08 2019Coherent combination of emission power from an array of coupled semiconductor lasers operating on the same chip is of fundamental and technological importance. In general, the nonlinear competition among the array supermodes can entail incoherence and ... More
Syntactic View of Sigma-Tau Generation of PermutationsMar 26 2019We give a syntactic view of the Sawada-Williams $(\sigma,\tau)$-generation of permutations. The corresponding sequence of $\sigma-\tau$-operations, of length $n!-1$ is shown to be highly compressible: it has $O(n^2\log n)$ bit description. Using this ... More
Coxeter Groups, Ruins, and Weighted $L^2$-cohomologyFeb 14 2016Given a Coxeter system $(W,S)$ and a multiparameter $\mathbf{q}$ of real numbers indexed by $S$, one can define the weighted $L^2$-cohomology groups and associate to them a nonnegative real number called the weighted $L^2$-Betti number. We show that for ... More
Critical trees: counterexamples in model checking of CSM systems using CBS algorithmOct 26 2017The important feature of temporal model checking is the generation of counterexamples. In the report, the requirements for generation of counterexample (called critical tree) in model checking of CSM systems are described. The output of TempoRG model ... More
Verification of Design Decisions in Communication Protocol by Evaluation of Temporal Logic FormulasOct 25 2017During the project of a communication protocol, many design decisions influence the behavior of the protocol and its correctness. Formal specification and verification of the protocol may prove its correctness. In this paper, an example of a verification ... More
Discrete Event Simulation of Personal Rapid Transit (PRT) SystemsMay 12 2017The article discusses issues related to the construction of the PRT network simulator and the simulation process: the elements of PRT network structure, their representation in the simulator, the simulation process itself, animation, and automation of ... More
Sample Variance in Free ProbabilityJul 22 2016May 12 2017Let $X_1, X_2,\dots, X_n$ denote i.i.d.~centered standard normal random variables, then the law of the sample variance $Q_n=\sum_{i=1}^n(X_i-\bar{X})^2$ is the $\chi^2$-distribution with $n-1$ degrees of freedom. It is an open problem in classical probability ... More
The fattened Davis complex and weighted $L^2$-(co)homology of Coxeter groupsFeb 26 2015Associated to a Coxeter system $(W,S)$ there is a contractible simplicial complex $\Sigma$ called the Davis complex on which $W$ acts properly and cocompactly by reflections. Given a positive real multiparameter $\mathbf{q}$, one can define the weighted ... More
Polygon Vertex Extremality and Decomposition of PolygonsApr 11 2010In this paper, we show that if we decompose a polygon into two smaller polygons, then by comparing the number of extremal vertices in the original polygon versus the sum of the two smaller polygons, we can gain at most two globally extremal vertices in ... More
State Space Reduction for Reachability Graph of CSM AutomataOct 25 2017Classical CTL temporal logics are built over systems with interleaving model concurrency. Many attempts are made to fight a state space explosion problem (for instance, compositional model checking). There are some methods of reduction of a state space ... More
Macrogeneration and Automata Libraries For COSMA design environmentOct 24 2017In ICS, WUT a COSMA design environment is being developed. COSMA is based on Concurrent State Machines (CSM) formalism of system specification. It contains a graphical tool for system design, various tools for the analysis (including a temporal model ... More
Threefold Analysis of Distributed Systems: IMDS, Petri Net and Distributed Automata DA3Oct 09 2017Integrated Model of Distributed Systems is used for specification and verification of distributed systems. In the formalism, a system is modeled as a set of servers' states and agents' messages. The operation of a system is modeled as actions converting ... More
The Four-Vertex Theorem, The Evolute, and The Decomposition of PolygonsJun 12 2009Jun 15 2009The Four-Vertex Theorem has been of interest ever since a discrete version appeared in 1813 due to Cauchy. Up until now, there have been many different versions of this theorem, both for discrete cases and smooth cases. In 2004, an approach relating the ... More
Supersymmetric microring laser arraysFeb 08 2019Feb 28 2019Coherent combination of emission power from an array of coupled semiconductor lasers operating on the same chip is of fundamental and technological importance. In general, the nonlinear competition among the array supermodes can entail incoherence and ... More
JADE - A Platform for Research on Cooperation of Physical and Virtual AgentsOct 24 2017In the ICS, WUT a platform for simulation of cooperation of physical and virtual mobile agents is under development. The paper describes the motivation of the research, an organization of the platform, a model of agent, and the principles of design of ... More
Behavioral an real-time verification of a pipeline in the COSMA environmentMar 16 2017The case study analyzed in the paper illustrates the example of model checking in the COSMA environment. The system itself is a three-stage pipeline consisting of mutually concurrent modules which also compete for a shared resource. System components ... More
Proposed benchmarks for PRT networks simulationOct 13 2017Personal Rapid Transit (PRT) is a promising form of urban transport. Its operation consists in the use of small unmanned vehicles which convey the passengers among stations within a dedicated network. Various aspects of the PRT network performance are ... More
Communication Dualism in Distributed Systems with Petri Net InterpretationOct 22 2017In the paper notion of communication dualism id formalized and explained in Petri net interpretation. We consider communication dualism a basic property of communication in distributed systems. The formalization is done in the Integrated Model of Distributed ... More
Priority Rules on ATN (PRT) IntersectionsDec 16 2017In Autonomous Transit Networks some basic elements influence the throughput: network structure, maximum velocity, number of vehicles etc. Other parameters like station structure, dynamic routing or vehicle behavior on intersections play minor role. Yet ... More
Numerical investigation on the fixed-stress splitting scheme for Biot's equations: Optimality of the tuning parameterJan 25 2018We study the numerical solution of the quasi-static linear Biot's equations solved iteratively by the fixed-stress splitting scheme. In each iteration the mechanical and flow problems are decoupled, where the flow problem is solved by keeping an artificial ... More
Distributed management of Personal Rapid Transit (PRT) vehicles under unusual transport conditionsMay 12 2017The paper presents a flexibility of management of vehicles in Personal Rapid Transit (PRT) network. The algorithm used for delivering empty vehicles for waiting passengers is based on multiparameter analysis. Due to its distributed construction, the algorithm ... More
Reconfiguring structured light beams using nonlinear metasurfacesMay 18 2018Ultra-compact, low-loss, fast, and reconfigurable optical components, enabling manipulation of light by light, could open numerous opportunities for controlling light on the nanoscale. Nanostructured all-dielectric metasurfaces have been shown to enable ... More
Derivation, interpretation, and analog modelling of fractional variable order derivative definitionApr 18 2013The paper presents derivation and interpretation of one type of variable order derivative definitions. For mathematical modelling of considering definition the switching and numerical scheme is given. The paper also introduces a numerical scheme for a ... More
Distributed algorithm for empty vehicles management in personal rapid transit (PRT) networkOct 17 2017In this paper, an original heuristic algorithm of empty vehicles management in personal rapid transit network is presented. The algorithm is used for the delivery of empty vehicles for waiting passengers, for balancing the distribution of empty vehicles ... More
Rybu: Imperative-style Preprocessor for Verification of Distributed Systems in the Dedan EnvironmentOct 07 2017Integrated Model of Distributed Systems (IMDS) is developed for specification and verification of distributed systems, and verification against deadlocks. On the basis of IMDS, Dedan verification environment was prepared. Universal deadlock detection ... More
The $e$-vector of a simplicial complexJun 13 2018We study the exponential Hilbert series (both coarsely- and finely-graded) of the Stanley-Reisner ring of an abstract simplicial complex, $\Delta$, and we introduce the $e$-vector of $\Delta$, which relates to the coefficients of the exponential Hilbert ... More
Model Checking in The COSMA Environment as a Support for The Design of Pipelined ProcessingMay 12 2017The case study analyzed in the report involves the behavioral specification and verification of a three-stage pipeline consisting of mutually concurrent modules which also compete for a shared resource. The system components are specified in terms of ... More
Using Machine Learning to Enhance Vehicles Traffic in ATN (PRT) SystemsDec 16 2017This paper discusses new techniques to enhance Automated Transit Networks (ATN, previously called Personal Rapid Transit - PRT) based on Artificial Intelligence tools. The main direction is improvement of the cooperation of autonomous modules that use ... More
Noncommutative probability of type DSep 05 2016We construct a deformed Fock space and a Brownian motion coming from Coxeter groups of type D. The construction is analogous to that of the $q$-Fock space (of type A) and the $(\alpha,q)$-Fock space (of type B).
Convolution, subordination and characterization problems in noncommutative probabilityApr 18 2015Characterization problems in free probability are studied here. Using subordination of free additive and free multiplicative convolutions we generalize some known characterizations in free probability to random variables with unbounded support. Using ... More
Fock space associated to Coxeter group of type BNov 28 2014In this article we construct a generalized Gaussian process coming from Coxeter groups of type B. It is given by creation and annihilation operators on an $(\alpha,q)$-Fock space, which satisfy the commutation relation $$ b_{\alpha,q}(x)b_{\alpha,q}^\ast(y)-qb_{\alpha,q}^\ast(y)b_{\alpha,q}(x)=\langle ... More
Noncommutative probability of type DSep 05 2016Jan 01 2017We construct a deformed Fock space and a Brownian motion coming from Coxeter groups of type D. The construction is analogous to that of the $q$-Fock space (of type A) and the $(\alpha,q)$-Fock space (of type B).
Practical Approach to Distributed Systems' DesignMay 16 2017The paper, based on authors' experience from several distributed systems integration projects, summarizes briefly practical designer's view on methodological requirements and overall system organization, including clues as to the organization of the application ... More
Accurate autocorrelation modeling substantially improves fMRI reliabilityNov 27 2017Sep 06 2018Given the recent controversies in some neuroimaging statistical methods, we compare the most frequently used functional Magnetic Resonance Imaging (fMRI) analysis packages: AFNI, FSL and SPM, with regard to temporal autocorrelation modeling. This process, ... More
Verification of Concurrent Engineering Software Using CSM ModelsApr 20 2017An engineering design process may involve software modules that can executed concurrently. Concurrent modules can be very easily subject to some synchronization errors. This paper discusses verification process for such engineering software. We present ... More
Cooperation of Multiple Autonomous Robots and Analysis of their Swarm BehaviorDec 28 2018In this paper, we extended previous studies of cooperating autonomous robots to include situations when environmental changes and changes in the number of robots in the swarm can affect the efficiency to execute tasks assigned to the swarm of robots. ... More
Improving Resilience of Autonomous Moving Platforms by Real Time Analysis of Their CooperationMay 11 2017Environmental changes, failures, collisions or even terrorist attacks can cause serious malfunctions of the delivery systems. We have presented a novel approach improving resilience of Autonomous Moving Platforms AMPs. The approach is based on multi-level ... More
Concurrent Software Design Based on Constraints on State DiagramsMar 23 2017Concurrent software for engineering computations consists of multiple cooperating modules. The behavior of individual modules is described by means on state diagrams. In the paper, the constraints on state diagrams are proposed, allowing for the specification ... More
System Modeling in the COSMA EnvironmentFeb 12 2017The aim of this paper is to demonstrate how the COSMA environment can be used for system modeling. This environment is a set of tools based on Concurrent State Machines paradigm and is developed in the Institute of Computer Science at the Warsaw University ... More
System level specification and verification using Concurrent State Machines and COSMA environmentMar 16 2017Traffic Light Controller, a typical benchmark device, is specified and verified using of a formal model called Concurrent State Machines (CSM) and the software environment COSMA 2.0, which supports the system level specification and analysis of concurrent, ... More
Application of retardation-modulation polarimetry in studies of nanocomposite materialsApr 23 2019We demonstrate an application of retardation-modulation polarimetry in studies of nanocomposite materials. Molecular ordering is explored on both nonchiral and chiral liquid crystals (LCs) in the bulk state and embedded into parallel-arrays of cylindrical ... More
The gradient flow structures of thermo-poro-visco-elastic processes in porous mediaJul 06 2019In this paper, the inherent gradient flow structures of thermo-poro-visco-elastic processes in porous media are examined for the first time. In the first part, a modelling framework is introduced aiming for describing such processes as generalized gradient ... More
The new computer program for three dimensional relativistic hydrodynamical modelJan 30 2006Feb 09 2006An effective computer program for three dimensional relativistic hydrodynamical model has been developed. It implements a new approach to the early hot phase of relativistic heavy-ion collisions. The computer program simulates time-space evolution of ... More
Efficient Representation and Counting of Antipower Factors in WordsDec 19 2018A $k$-antipower (for $k \ge 2$) is a concatenation of $k$ pairwise distinct words of the same length. The study of antipower factors of a word was initiated by Fici et al. (ICALP 2016) and first algorithms for computing antipower factors were presented ... More
Faster Recovery of Approximate Periods over Edit DistanceJul 27 2018The approximate period recovery problem asks to compute all $\textit{approximate word-periods}$ of a given word $S$ of length $n$: all primitive words $P$ ($|P|=p$) which have a periodic extension at edit distance smaller than $\tau_p$ from $S$, where ... More
On the optimization of the fixed-stress splitting for Biot's equationsNov 15 2018Dec 10 2018In this work we are interested in effectively solving the quasi-static, linear Biot model for poromechanics. We consider the fixed-stress splitting scheme, which is a popular method for iteratively solving Biot's equations. It is well-known that the convergence ... More
Quantitive and sociological analysis of blog networksJun 07 2005This paper examines the emerging phenomenon of blogging, using three different Polish blogging services as the base of the research. Authors show that blog networks are sharing their characteristics with complex networks gamma coefficients, small worlds, ... More
Anderson accelerated fixed-stress splitting schemes for consolidation of unsaturated porous mediaMay 11 2018In this paper, we study the robust linearization of nonlinear poromechanics of unsaturated materials. The model of interest couples the Richards equation with linear elasticity equations, employing the equivalent pore pressure. In practice a monolithic ... More
Additive colorings of planar graphsFeb 03 2012Feb 06 2012An \emph{additive coloring} of a graph $G$ is an assignment of positive integers $\{1,2,...,k\}$ to the vertices of $G$ such that for every two adjacent vertices the sums of numbers assigned to their neighbors are different. The minimum number $k$ for ... More
PRT (Personal Rapid Transit) network simulationOct 18 2017Transportation problems of large urban conurbations inspire search for new transportation systems, that meet high environmental standards, are relatively cheap and user friendly. The latter element also includes the needs of disabled and elderly people. ... More
Quasi-Linear-Time Algorithm for Longest Common Circular FactorJan 31 2019We introduce the Longest Common Circular Factor (LCCF) problem in which, given strings $S$ and $T$ of length $n$, we are to compute the longest factor of $S$ whose cyclic shift occurs as a factor of $T$. It is a new similarity measure, an extension of ... More
Magnetic anisotropy of epitaxial (Ga,Mn)As on (113)A GaAsFeb 02 2010Feb 08 2010The temperature dependence of magnetic anisotropy in (113)A (Ga,Mn)As layers grown by molecular beam epitaxy is studied by means of superconducting quantum interference device (SQUID) magnetometry as well as by ferromagnetic resonance (FMR) and magnetooptical ... More
Circular Pattern Matching with $k$ MismatchesJul 03 2019The $k$-mismatch problem consists in computing the Hamming distance between a pattern $P$ of length $m$ and every length-$m$ substring of a text $T$ of length $n$, if this distance is no more than $k$. In many real-world applications, any cyclic shift ... More
A ferroelectric liquid crystal confined in cylindrical nanopores: Reversible smectic layer buckling, enhanced light rotation and extremely fast electro-optically active Goldstone excitationsNov 27 2017The orientational and translational order of a thermotropic ferroelectric liquid crystal (2MBOCBC) imbibed in self-organized, parallel, cylindrical pores with radii of 10, 15, or 20 nm in anodic aluminium oxide monoliths (AAO) are explored by high-resolution ... More
Magnetization dynamics down to zero field in dilute (Cd,Mn)Te quantum wellsOct 17 2008The evolution of the magnetization in (Cd,Mn)Te quantum wells after a short pulse of magnetic field was determined from the giant Zeeman shift of spectroscopic lines. The dynamics in absence of magnetic field was found to be up to three orders of magnitude ... More
Structural and paramagnetic properties of dilute Ga1-xMnxNDec 21 2009Jul 21 2011Systematic investigations of the structural and magnetic properties of single crystal (Ga,Mn)N films grown by metal organic vapor phase epitaxy are presented. High resolution transmission electron microscopy, synchrotron x-ray diffraction, and extended ... More
GaMnN epitaxial films with high magnetizationMay 15 2012May 17 2012We report on the fabrication of pseudomorphic wurtzite GaMnN grown on GaN with Mn concentrations up to 10% using molecular beam epitaxy. According to Rutherford backscattering the Mn ions are mainly at the Ga-substitutional positions, and they are homogeneously ... More
Comprehensive evaluation of statistical speech waveform synthesisNov 15 2018Dec 11 2018Statistical TTS systems that directly predict the speech waveform have recently reported improvements in synthesis quality. This investigation evaluates Amazon's statistical speech waveform synthesis (SSWS) system. An in-depth evaluation of SSWS is conducted ... More
Manipulating Mn--Mg$_k$ cation complexes to control the charge- and spin-state of Mn in GaNNov 13 2013Owing to the variety of possible charge and spin states and to the different ways of coupling to the environment, paramagnetic centres in wide band-gap semiconductors and insulators exhibit a strikingly rich spectrum of properties and functionalities, ... More
Human Tissues Investigation Using PALS TechniqueNov 13 2017Samples of uterine leiomyomatis and normal tissues taken from patients after surgery were investigated using the Positron Annihilation Lifetime Spectroscopy (PALS). Significant differences in all PALS parameters between normal and diseased tissues were ... More
LHCb VELO Timepix3 TelescopeFeb 26 2019The LHCb VELO Timepix3 telescope is a silicon pixel tracking system constructed initially to evaluate the performance of LHCb VELO Upgrade prototypes. The telesope consists of eight hybrid pixel silicon sensor planes equipped with the Timepix3 ASIC. The ... More