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Appearance-based approach to hybrid metric-topological simultaneous localisation and mapping

IET INTELLIGENT TRANSPORT SYSTEMS 2014年第8期8卷 688-699页

作者： Fernandez, Lorenzo Paya, Luis Reinoso, Oscar Miguel Jimenez, Luis Univ Miguel Hernandez Dept Ingn Sistemas Ind Alicante Spain

In this study a unified framework to carry out the simultaneous localisation and mapping of a mobile robot combining metric and topological techniques is presented. The robot moves in a real indoor environment and the algorithm makes use of the information provided by an omnidirectional camera mounted on the robot and its internal odometry. The hybrid approach consists in constructing simultaneously two maps of the environment, one metric and other topological with relationships between them which are updated in each step. The robot goes through the environment to build up a map while continuously captures images. To build the topological map the most relevant information from the scenes is extracted using a global appearance descriptor. A new node is added to the map when the appearance between two images is sufficiently different. Also, the authors check if there is a loop closure with a previous node. At the same time, a metrical map of the environment is computed. With this aim, the authors estimate the position of the robot when it captures a new image using a monte-carlo algorithm. The authors show how it is possible to obtain a reasonable performance both in time and accuracy in an indoor environment, when the involved parameters are properly tuned.

关键词： SLAM (robots) robot vision mobile robots feature extraction monte carlo methods cameras appearance-based approach hybrid metric-topological simultaneous localisation and mapping mobile robot indoor environment omnidirectional camera internal odometry global appearance descriptor scene extraction loop closure monte-carlo algorithm position estimation

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Method of lines for stochastic boundary-value problems with additive noise

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APPLIED MATHEMATICS AND COMPUTATION 2008年第1期199卷 301-314页

作者： Roessler, Andreas Seaid, Mohammed Zahri, Mostafa Goethe Univ Frankfurt Fachbereich Math D-60054 Frankfurt Germany Tech Univ Darmstadt Fachbereich Math D-64289 Darmstadt Germany Univ Kaiserslautern Fachbereich Math D-67663 Kaiserslautern Germany

We propose a new numerical method for solving stochastic boundary-value problems. The method uses the deterministic method of lines to treat the time, space and randomness separately. The emphasis in the present study is given to stochastic partial differential equations with forced additive noise. The spatial discretization is carried out using a second-order finite volume method, while the associated stochastic differential system is numerically solved using a class of stochastic Runge-Kutta methods. The performance of the proposed methods is tested for a stochastic advection-diffusion problem and a stochastic Burgers equation driven with white noise. Numerical results are presented in both one and two space dimensions. (C) 2007 Elsevier Inc. All rights reserved.

关键词： stochastic partial differential equations method of lines stochastic Runge-Kutta schemes white noise monte-carlo algorithm

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Modeling of operational safeguard for power productions in the nuclear power plants (NPPs)

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ENERGY EXPLORATION & EXPLOITATION 2010年第6期28卷 433-449页

作者： Woo, Tae-Ho Lee, Un-Chul Seoul Natl Univ Dept Nucl Engn Seoul 151742 South Korea

Power operations for secure performance are investigated using non-linear algorithm. The object of the simulation is to find the safe operation with safeguard for the life-extension of the operations. The network effect of the game theory is used for the quantification which is incorporated with the monte-carlo method. The characteristics of the nuclear power plants (NPPs) are analyzed by the designed occurrence value as the refueling factor (RF) and the safeguard measures factor (SMF) which are used for the basic element. The random sampling for the event frequency is used by the characteristics of network effect method like the zero-sum quantification, because it is impossible to expect the time of terror incident exactly. Three kinds of considerations are basic elements as the nuclear fuel, system, and safeguard properties which are organized as an aspect of safeguard considerations. The maximum value of secure operation is the 13.0 in 14(th) month and the minimum value is 1.0 in several months during 10 years. Hence, the stability of the secure power operation increases 13 times higher than the lowest value in this study. The conclusions give that the secure operation is changeable in the designed NPPs.

关键词： Nuclear Power Plants Safeguard Life-extension Network Effect monte-carlo algorithm

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Lagrange approach in stochastic quantization of the 2D Hubbard model

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PHYSICA STATUS SOLIDI B-BASIC RESEARCH 2000年第1期219卷 125-131页

作者： Kalinkin, AN Skorikov, VM Russian Acad Sci Inst Gen & Inorgan Chem Moscow 117907 Russia

A new method of the generation of Green's function in external local and bilocal fields is proposed for the stochastic quantization of the 2D Hubbard model. The differential equations for Green's functions transform to the system of integral equations and it is solved numerically for a local Hubbard-Stratanovich field. The Trotter-Suzuki expansion and the matrix elements of the evolution operator are not used in this approach. For a 4x4 lattice with half-filled band the total energy E, the density n, the density-density [n(i up arrow)n(i down arrow)] and spin-spin [(SiSjz)-S-z] correlation functions were calculated by stochastic quantization as the functions of one-site repusion U and inverse temperature beta. The obtained results are in agreement with the previous monte carlo calculations.

关键词： monte-carlo algorithm Pairing correlations monte-carlo CALCULATION Hubbard model Quantization Lagrange Green\'s function Stochastic Integral equations

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High performance modelling of the transport of energetic particles for photon radiotherapy

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PHYSICA MEDICA-EUROPEAN JOURNAL OF MEDICAL PHYSICS 2017年 42卷 305-312页

作者： Birindelli, Gabriele Feugeas, Jean-Luc Caron, Jerome Dubroca, Bruno Kantor, Guy Page, Jonathan Pichard, Teddy Tikhonchuk, Vladimir Nicolai, Philippe Univ Bordeaux CNRS CEA CELIACtr Laser Intenses & Applicat F-33400 Talence France Inst Bergonie Comprehens Canc Ctr Dept Radiotherapy F-33076 Bordeaux France

This work consists of the validation of a new Grid Based Boltzmann Solver (GBBS) conceived for the description of the transport and energy deposition by energetic particles for radiotherapy purposes. The entropic closure and a compact mathematical formulation allow our code (M1) to calculate the delivered dose with an accuracy comparable to the monte-carlo (MC) codes with a computational time that is reduced to the order of few minutes without any special processing power requirement. A validation protocol with heterogeneity inserts has been defined for different photon sources. The comparison with the MC calculated depth-dose curves and transverse profiles of the beam at different depths shows an excellent accuracy of the M1 model. (C) 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

关键词： Radiotherapy treatment planning system Deterministic dose calculation monte-carlo algorithm Boltzmann equation

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Convergence from Boltzmann to Landau processes with soft potential and particle approximations

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JOURNAL OF STATISTICAL PHYSICS 2003年第3-4期111卷 931-966页

作者： Guérin, H Méléard, S Univ Paris 10 UFR SEGMI MODALX F-92000 Nanterre France Univ Paris 06 & 7 UMR 7599 Lab Probabilites & Modeles Aleatoires F-75252 Paris 05 France

Our aim in this paper is to show how a probabilistic interpretation of the Boltzmann and Landau equations gives a microscopic understanding of these equations. We firstly associate stochastic jump processes with the Boltzmann equations we consider. Then we renormalize these equations following asymptotics which make prevail the grazing collisions, and prove the convergence of the associated Boltzmann jump processes to a diffusion process related to the Landau equation. The convergence is pathwise and also implies a convergence at the level of the partial differential equations. The best feature of this approach is the microscopic understanding of the transition between the Boltzmann and the Landau equations, by an accumulation of very small jumps. We deduce from this interpretation an approximation result for a solution of the Landau equation via colliding stochastic particle systems. This result leads to a monte-carlo algorithm for the simulation of solutions by a conservative particle method which enables to observe the transition from Boltzmann to Landau equations. Numerical results are given.

关键词： Soft potential Boltzmann equations without cutoff Landau equation with soft potential nonlinear stochastic differential equations interacting particle systems monte-carlo algorithm

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A Fast Radiative Transfer Model for the Meteor-M satellite-based hyperspectral IR sounders

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IZVESTIYA ATMOSPHERIC AND OCEANIC PHYSICS 2014年第9期50卷 968-977页

作者： Uspensky, A. B. Rublev, A. N. Rusin, E. V. Pyatkin, V. P. Planeta State Res Ctr Moscow 123242 Russia Russian Acad Sci Siberian Branch Inst Computat Math & Math Geophys Novosibirsk 630090 Russia

The methodological and computational aspects of Fast Radiative Transfer Model (FRTM) development designed for the analysis and validation of the data of measurements using satellite-based instrument-hyperspectral IR sounders of high spectral resolution-are considered. A description of the FRTM is given for the analysis and modeling of the measurements by the IRFS-2 IR Fourier spectrometer for polarorbiting meteorological satellites of the Meteor-M series based on the known RTTOV FRTM. Computational efficiency is estimated and the results of the verification of developed FRTM are presented. They were obtained from a comparison of model simulations with exact line-by-line calculations for the IRFS-2 IR sounder. The increase in computational performance and the accuracy of the FRTM, caused by the application of the algorithms of the principal components method, are discussed. The construction of radiative models, which use the algorithm of the monte carlo method and are applicable for the analysis and modeling of the data of IR sounders under conditions of cloudiness in the instrument field of view, is considered.

关键词： fast radiative transfer model IR-sounder IRFS-2 remote sensing satellite data modeling RTTOV optical depth Jacobian monte-carlo algorithm

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SIMULATED ANNEALING APPROACH TO THE STUDY OF PROTEIN STRUCTURES

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PROTEIN ENGINEERING 1991年第6期4卷 661-667页

作者： CHOU, KC CARLACCI, L Computational Chemistry. Upjohn Research Laboratories Kalamazoo. MI 49001 USA

One of the most difficult problems in predicting the three dimensional structure of proteins is how to deal with the local minimum problem. In many cases of practical interest this problem has been reduced to how to select an appropriate set of starting conformations for carrying out energy minimizations. How these starting conformations are selected, however, is often based on the physical intuition of the person doing the calculations, and hence it is hard to avoid bearing some sort of arbitrariness. To improve such a situation, we introduced the simulated annealing monte carlo algorithm to locate the optimal starting conformations for energy minimizations. The method developed here is valid for both single and multiple polypeptide chain systems. The annealing process can be conducted with respect to either the internal dihedral angles of a polypeptide chain or the external rotations and translations of various constituent polypeptide chains, and hence is particularly useful for studying the packing arrangements of secondary structures in proteins, such as helix/helix packing, helix/sheet packing and sheet/sheet packing. It was shown via a number of comparative calculations that the final structures obtained through the annealing process not only had lower energies than the corresponding energy-minimized structures reported previously, but also assumed the forms closer to the observations in proteins. All these results indicate that a better result can be obtained in search of low-energy structures of proteins by incorporating the simulated annealing approach. It has been observed during simulated annealing for each of these cases that there is a critical temperature T*, termed as 'phase transition point', around which the energy has a remarkable drop and below which the decrease in energy gradually becomes steady and slow.

关键词： ENERGY MINIMIZATION 4-HELIX BUNDLE monte-carlo algorithm PHASE TRANSITION POINT SIDE-CHAIN CONFORMATION

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Computation of Greeks using Malliavin's calculus in jump type market models

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ELECTRONIC JOURNAL OF PROBABILITY 2006年第none期11卷 276-300页

作者： Bavouzet-Morel, MP Messaoud, M INRIA Rocquencourt Projet MATHFI F-78150 Le Chesnay France IXIS F-75648 Paris 13 France

We use the Malliavin calculus for Poisson processes in order to compute sensitivities for European and Asian options with underlying following a jump type diffusion. The main point is to settle an integration by parts formula ( similar to the one in the Malliavin calculus) for a general multidimensional random variable which has an absolutely continuous law with differentiable density. We give an explicit expression of the differential operators involved in this formula and this permits to simulate them and consequently to run a monte carlo algorithm.

关键词： Malliavin calculus monte-carlo algorithm Euler scheme compound Poisson process sensitivity analysis European options Asian options

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On the randomized solution of initial value problems

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JOURNAL OF COMPLEXITY 2011年第3-4期27卷 300-311页

作者： Daun, Thomas Univ Kaiserslautern Dept Comp Sci D-67653 Kaiserslautern Germany

We study the randomized solution of initial value problems for systems of ordinary differential equations y' (x) = f (x, y(x)), x is an element of [a, b], y(a) =y(0) is an element of R(d). Recently Heinrich and Milla (2008) [4] presented an order optimal randomized algorithm solving this problem for gamma-smooth input data (i.e. gamma = r + rho: the r-th derivatives off satisfy a rho-Holder condition). This algorithm uses function values and values of derivatives of f. In this paper we present an order optimal randomized algorithm for the class of gamma-smooth functions that uses only values off. For this purpose we show how to obtain an order optimal randomized algorithm from an order (sub)optimal deterministic one. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Initial value problem Ordinary differential equation monte-carlo algorithm Complexity

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