An Extension to Hough Transform Based on Gradient Orientation

The Hough transform is one of the most common methods for line detection. In this paper we propose a novel extension of the regular Hough transform. The proposed extension combines the extension of the accumulator space and the local gradient orientation resulting in clutter reduction and yielding more prominent peaks, thus enabling better line identification. We demonstrate benefits in applications such as visual quality inspection and rectangle detection.Comment: Part of the Proceedings of the Croatian Computer Vision Workshop, CCVW 2015, Year

Spectrum of elementary excitations in Galilean-invariant integrable models

The spectrum of elementary excitations in one-dimensional quantum liquids is generically linear at low momenta. It is characterized by the sound velocity that can be related to the ground state energy. Here we study the spectrum at higher momenta in Galilean invariant integrable models. Somewhat surprisingly, we show that the spectrum at arbitrary momentum is fully determined by the properties of the ground state. We find general exact relations for the coefficients of several terms in the expansion of the excitation energy at low momenta and arbitrary interaction and express them in terms of the Luttinger liquid parameter. We apply the obtained formulas to the Lieb-Liniger model and obtain several new results.Comment: 5 page

Simulation study of random sequential adsorption of mixtures on a triangular lattice

Random sequential adsorption of binary mixtures of extended objects on a two-dimensional triangular lattice is studied numerically by means of Monte Carlo simulations. The depositing objects are formed by self-avoiding random walks on the lattice. We concentrate here on the influence of the symmetry properties of the shapes on the kinetics of the deposition processes in two-component mixtures. Approach to the jamming limit in the case of mixtures is found to be exponential, of the form: $\theta(t) \sim \theta_{jam}-\Delta\theta \exp (-t/\sigma),$ and the values of the parameter $\sigma$ are determined by the order of symmetry of the less symmetric object in the mixture. Depending on the local geometry of the objects making the mixture, jamming coverage of a mixture can be either greater than both single-component jamming coverages or it can be in between these values. Results of the simulations for various fractional concentrations of the objects in the mixture are also presented.Comment: 11 figures, 2 table

Fluctuation-induced noise in out-of-equilibrium disordered superconducting films

We study out-of-equilibrium transport in disordered superconductors close to the superconducting transition. We consider a thin film connected by resistive tunnel interfaces to thermal reservoirs having different chemical potentials and temperatures. The nonequilibrium longitudinal current-current correlation function is calculated within the nonlinear sigma model description and nonlinear dependence on temperatures and chemical potentials is obtained. Different contributions are calculated, originating from the fluctuation-induced suppression of the quasiparticle density of states, Maki- Thompson and Aslamazov-Larkin processes. As a special case of our results, close-to-equilibrium we obtain the longitudinal ac conductivity using the fluctuation-dissipation theorem

Određivanje spektra antineutrina iz nuklearnih reaktora

Motivaciju za izradu ovog diplomskog rada predstavljaju oscilacije neutrina u nuklearnim reaktorima. U tu svrhu potrebno je dobro poznavanje spektra antineutrina. Princip rada nuklearnih reaktora se temelji na fisiji, a “gorivo” čine četiri atoma: 235U, 238U, 239Pu i 241Pu. Naime, prilikom fisije se stvaraju produkti čiji raspon seže od jezgara u dolini ß-stabilnosti do vrlo nestabilnih jezgara bogatih neutronima. Upravo te nestabilne jezgre svojim ß-raspadom proizvode elektrone i antineutrine. Budući da je većina dobivenih jezgara veoma egzotična – nije ih moguće istraživati postojećim eksperimentalnim pogonima. Stoga je nužno okrenuti se teorijskom opisu nuklearne strukture. Konkretno, cilj ovog rada je koristiti mikroskopski model nuklearne strukture koji se bazira na relativističkom nuklearnom funkcionalu gustoće te pomoću njega reproducirati eksperimentalni spektar elektrona i tako odrediti spektar antineutrina. Zahvaljujući tom pristupu, iz dobivenih rezultata se još može procijeniti i udio doprinosa zabranjenih prijelaza u ukupnim spektrima, što nije bio slučaj kod dosadašnjih postupaka koji su se oslanjali na pretvorbu mjerenog spektra elektrona u spektar antineutrina