Denoising of sparse images in impulsive disturbance environment

Multimedia Tools and Applications - The paper presents a method for denoising and reconstruction of sparse images based on a gradient-descent algorithm. It is assumed that the original (non-noisy)...     

Aesthetical criterion in art and science

Neural Computing and Applications - In the paper, the authors elaborate a recent research concerning the originality of artworks in terms of self-organization in the complex systems physics. It has...     

Scalable Realistic Rendering with Many‐Light Methods

Recent years have seen increasing attention and significant progress in many‐light rendering, a class of methods for efficient computation of global illumination. The many‐light formulation offers a unified mathematical framework for the problem reducing the full lighting transport simulation to the calculation of the direct illumination from many virtual light sources. These methods are unrivaled in their scalability: they are able to produce plausible images in a fraction of a second but also converge to the full solution over time. In this state‐of‐the‐art report, we give an easy‐to‐follow, introductory tutorial of the many‐light theory; provide a comprehensive, unified survey of the topic with a comparison of the main algorithms; discuss limitations regarding materials and light transport phenomena and present a vision to motivate and guide future research. We will cover both the fundamental concepts as well as improvements, extensions and applications of many‐light rendering.     

Tensor Clustering for Rendering Many‐Light Animations

Rendering animations of scenes with deformable objects, camera motion, and complex illumination, including indirect lighting and arbitrary shading, is a long‐standing challenge. Prior work has shown that complex lighting can be accurately approximated by a large collection of point lights. In this formulation, rendering of animation sequences becomes the problem of efficiently shading many surface samples from many lights across several frames. This paper presents a tensor formulation of the animated many‐light problem, where each element of the tensor expresses the contribution of one light to one pixel in one frame. We sparsely sample rows and columns of the tensor, and introduce a clustering algorithm to select a small number of representative lights to efficiently approximate the animation. Our algorithm achieves efficiency by reusing representatives across frames, while minimizing temporal flicker. We demonstrate our algorithm in a variety of scenes that include deformable objects, complex illumination and arbitrary shading and show that a surprisingly small number of representative lights is sufficient for high quality rendering. We believe out algorithm will find practical use in applications that require fast previews of complex animation.     

The Active XML project: an overview

This paper provides an overview of the Active XML project developed at INRIA over the past five years. Active XML (AXML, for short), is a declarative framework that harnesses Web services for distributed data management, and is put to work in a peer-to-peer architecture. The model is based on AXML documents, which are XML documents that may contain embedded calls to Web services, and on AXML services, which are Web services capable of exchanging AXML documents. An AXML peer is a repository of AXML documents that acts both as a client by invoking the embedded service calls, and as a server by providing AXML services, which are generally defined as queries or updates over the persistent AXML documents. The approach gracefully combines stored information with data defined in an intensional manner as well as dynamic information. This simple, rather classical idea leads to a number of technically challenging problems, both theoretical and practical. In this paper, we describe and motivate the AXML model and language, overview the research results obtained in the course of the project, and show how all the pieces come together in our implementation. The first and third authors were partially funded by the European Project Edos. Work done when the second and third authors were at INRIA. Work done when the second and third authors were at INRIA.     

A variable-precision square root implementation for field programmable gate arrays

Applications requiring variable-precision arithmetic often rely on software implementations because custom hardware is either unavailable or too costly to build. By using the flexibility of the Xilinx XC4010 field programmable gate arrays, we present a hardware implementation of square root that is easily tailored to any desired precision. Our design consists of three types of modules: a control logic module, a data path module to extend the precision in 4-bit increments, and an interface module to span multiple chips. Our data path design avoids the common problem of large fan-out delay in the critical path. Cycle time is independent of precision, and operation latency can be independent of interchip communication delays.Notation S_j square root digit of weight 2^–j - S _j {–1, 0, 1} - S[j] computed square root value as of stepj - S _j ^s sign bit in the representation ofS _j in sign and magnitude form - S _j ^m magnitude bit in the representation ofS _j in sign and magnitude form - w[j] residual at stepj in two's complement carry-save representation - a sum vector in the carry-save representation of 2w[j] - b carry vector in the carry-save representation of 2w[j] - a _i bit of weight 2^–i in the sum vector,a - b_i bit of weight 2^–i in the carry vector,b - T[j]=–S[j – 1]s_j – s _j ² 2^–(j+1) T _i bit of weight 2^–i inT     

Effect of reduction parameters on the particle size of tungsten monocarbide obtained from the blue tungsten oxide

Conclusions A study was made, using the methods of particle size analysis and metallographic examination, of the effects of temperature and bed thickness in the reduction of the blue tungsten oxide upon some properties of tungsten and tungsten monocarbide powders and sintered 6 wt.% Co hard alloys produced from the monocarbide powders. Quantitative results were obtained showing the relationship between these reduction parameters on the one hand and the particle size of the resultant powders and the physicomechanical properties of hard alloys on the other. It was established that the particle size grows with rise in reduction temperature and with increase in the thickness of the blue oxide bed.Translated from Poroshkovaya Metallurgiya, No. 11(143), pp. 102–107, November, 1974.     

Prenatal gunshot perforation of the colon

Digitoxin plasma levels were determined in the dog by radioimmunoassy after i.v. infusion of this cardenolide in toxic amounts (388 +/- 13 mug/kg). Plasma values found immediately after the administration of this dose were 588.5 +/- 91 ng/ml and attained very low levels (10 ng/ml) 96 h later. The dominant half-life of digitoxin in the dog was found to be 49.6 +/- 6.5 h, but this value was attained only in the final part of our study. The results found are compared with previous data and controversial aspects are discussed.     

Comparison of different modes of excitation in X-ray emission spectroscopy in the detection of trace elements in coal and coal ash

Three different modes of sample excitation in X-ray emission spectroscopy were used in trace element analysis of coal and coal ash: proton beam, Mo X-ray tube and radioactive sources ⁵⁷Co and ¹⁰⁹Cd. The results of analysis are presented and methods and their possibilities are compared in order to indicate the most appropriate technique for the particular purpose.     

Linear models‐based LPV modelling and control for wind turbines

The non‐linear behaviour of wind turbines demands control strategies that guarantee the robustness of the closed‐loop system. Linear parameter‐varying (LPV) controllers adapt their dynamics to the system operating points, and the robustness of the closed loop is guaranteed in the controller design process. An LPV collective pitch controller has been developed within this work to regulate the generator speed in the above rated power production control zone. The performance of this LPV controller has been compared with two baseline control strategies previously designed, on the basis of classical gain scheduling methods and linear time‐invariant robust H_∞ controllers. The synthesis of the LPV controller is based on the solution of a linear matrix inequalities system, proposed in a mixed‐sensitivity control scenario where not only weight functions are used but also an LPV model of the wind turbine is necessary. As a contribution, the LPV model used is derived from a family of linear models extracted from the linearization process of the wind turbine non‐linear model. The offshore wind turbine of 5 MW defined in the Upwind European project is the used reference non‐linear model, and it has been modelled using the GH Bladed 4.0 software package. The designed LPV controller has been validated in GH Bladed, and an exhaustive analysis has been carried out to calculate fatigue load reductions on wind turbine components, as well as to analyse the load mitigation in some extreme cases. Copyright © 2014 John Wiley & Sons, Ltd.