Paraboloid–aspheric lenses free of spherical aberration

A method to design singlet paraboloid-aspheric lenses free of all orders of spherical aberration with maximum aperture is described. This work includes all parametric formulas to describe paraboloid-aspheric or aspheric-paraboloid lenses for any finite conjugated planes. It also includes the Schwarzchilds approximations (which can be used to calculate one rigorous propagation of light waves in physic optics) to design convex paraboloid-aspheric lenses for imaging an object at infinity, with explicit formulas to calculate thicknesses easily. The results were verified with software through ray tracing.     

Piezotronic Tuning of Potential Barriers in ZnO Bicrystals

Coupling of magnetic, ferroelectric, or piezoelectric properties with charge transport at oxide interfaces provides the option to revolutionize classical electronics. Here, the modulation of electrostatic potential barriers at tailored ZnO bicrystal interfaces by stress‐induced piezoelectric polarization is reported. Specimen design by epitaxial solid‐state transformation allows for both optimal polarization vector alignment and tailoring of defect states at a semiconductor–semiconductor interface. Both quantities are probed by transmission electron microscopy. Consequently, uniaxial compressive stress affords a complete reduction of the potential barrier height at interfaces with head‐to‐head orientation of the piezoelectric polarization vectors and an increase in potential barrier height at interfaces with tail‐to‐tail orientation. The magnitude of this coupling between mechanical input and electrical transport opens pathways to the design of multifunctional electronic devices like strain triggered transistors, diodes, and stress sensors with feasible applications for human–computer interfacing.     

Natural abundance variations in stable isotopes and their potential uses in animal physiological ecology

Chemical, biological, and physical processes lead to distinctive "isotopic signatures" in biological materials that allow tracing of the origins of organic substances. Isotopic variation has been extensively used by plant physiological ecologists and by paleontologists, and recently ecologists have adopted the use of stable isotopes to measure ecosystem patterns and processes. To date, animal physiological ecologists have made minimal use of naturally occurring stable isotopes as tracers. Here we provide a review of the current and potential uses of naturally occurring stable isotopes in animal physiological ecology. We outline the physical and biological processes that lead to variation in isotopic abundance in plants and animals. We summarize current uses in animal physiological ecology (diet reconstruction and animal movement patterns), and suggest areas of research where the use of stable isotopes can be fruitful (protein balance and turnover and the allocation of dietary nutrients). We argue that animal physiological ecologists can benefit from including the measurement of naturally occurring stable isotopes in their battery of techniques. We also argue that animal physiologists can make an important contribution to the emerging field of stable isotopes in biology by testing experimentally the plethora of assumptions upon which the techniques rely.     

3-D Reconstruction of Urban Scenes from Image Sequences

In this paper, we address the problem of the recovery of a realistic textured model of a scene from a sequence of images, without any prior knowledge either about the parameters of the cameras or about their motion. We do not require any knowledge of the absolute coordinates of some control points in the scene to achieve this goal. First, using various computer vision tools, we establish correspondences between the images and recover the epipolar geometry, from which we show how to compute the complete set of perspective projection matrices for all camera positions. Then, we proceed to reconstruct the geometry of the scene. We show how to rely on information of the scene such as parallel lines or known angles in order to reconstruct the geometry of the scene up to, respectively, an unknown affine transformation or an unknown similitude. Alternatively, if this information is not available, we can still recover the Euclidean structure of the scene through the techniques of self-calibration. The scene geometry is modeled as a set of polyhedra. Textures to be mapped on the scene polygons are extracted automatically from the images. We show how several images can be combined through mosaicing in order to automatically remove visual artifacts such as pedestrians or trees from the textures.This vision system has been implemented as a vision server, which provides to a CAD-CAM modeler geometry or texture information extracted from the set of images. The whole system allows efficient and fast production of scene models of high quality for such applications as simulation, virtual, or augmented reality.     

A software modeling approach for the design and analysis of cooperative optimization systems

Optimization problems are ubiquitous in our daily lives and one way to cope with them is using cooperative optimization systems that allow to obtain good enough, fast enough, and cheap enough solutions. From a practical point of view, the design and the analysis of such systems are complex tasks. In this work, an integrated system (DACOS) for helping in the design and analysis of cooperative, centralized optimization systems is presented. Also, the methodology used for the creation of DACOS (mainly, the use of software modeling) is described in detail. This may also be useful for researchers who want to build up their own system for their particular needs. DACOS has been developed using the Eclipse developing framework, which, among other advantages, is also able to automatically generate source code. Finally, a practical case of use is presented: the application of DACOS to the configuration and analysis of a cooperative strategy on a location problem. Copyright © 2010 John Wiley & Sons, Ltd.     

Dependability issues in visual–haptic interfaces

Dependability of a system is commonly referred to its reliability, its availability and its maintenability (RAM), but when this concept is applied to user interfaces there is no common agreement on what aspects of user–system interaction are related to a satisfactory RAM level for the whole system. In particular, when dealing with haptic systems, interface dependability may become a crucial issue in medical and in military domains when life-critical systems are to be manipulated or where costly remote control operations are to be performed, like in industrial processes control or in aerospace/automotive engineering and manufacturing. This paper discusses the role of dependability in haptic user interfaces, aiming to the definition of a framework for the assessment of the usability and dependability properties of haptic systems and their possible correlations. The research is based on the analysis of a visual–haptic-based simulator targeted to maintenance activity training for aerospace industry which is taken as a case study. As a result, we propose a novel framework able to collect and then process relevant interaction data during the execution of haptic tasks, enabling to analyze dependability vs. usability correlations.     

Safe operation of mini UAVs: a review of regulation and best practices

This paper is focused on the safety of mini UAV (mUAV) systems. It presents the great efforts that are being done in air legislation, including the present and future normative. Nevertheless, considering that the work is not finished yet, a low-level risk analysis concept is introduced. Based on the international regulations, a specific three-step structure for mUAV hazard analysis is presented: identification, assessment, and reduction in a recursive loop that provides a solid architecture for facing the wide range of possible risks.     

The UNESCO IDAMS Software Packages: Internationally Developed Data Analysis and Management Software

Abstract

There are many social economic and technical obstacles to the introduction of information technology [IT] in third world countries. These countries not only face barriers raised by their own circumstances but also those which impede any process of technical innovation; whatever the environment. The study described below investigated the extent to which six factors—funding, resistance to change, organizational policy, training, hardware/software availability and individual confidence—were restraining computerization.

The study was conducted amongst accounting and finance specialists in developing and least developed countries. Using strategic informant sampling techniques, data were collected from 210 respondents, spread over thirty nine countries. The study found that some of the six factors were considered by the respondents to be seriously inhibiting computerization. Other factors, particularly employee resistance to change, were not seen as important constraints. In some areas the study found significant differences between the responses from developed and least developed countries.     

The UJI librarian robot

This paper describes the UJI librarian robot, a mobile manipulator that is able to autonomously locate a book in an ordinary library, and grasp it from a bookshelf, by using eye-in-hand stereo vision and force sensing. The robot is only provided with the book code, a library map and some knowledge about its logical structure and takes advantage of the spatio-temporal constraints and regularities of the environment by applying disparate techniques such as stereo vision, visual tracking, probabilistic matching, motion estimation, multisensor-based grasping, visual servoing and hybrid control, in such a way that it exhibits a robust and dependable performance. The system has been tested, and experimental results show how it is able to robustly locate and grasp a book in a reasonable time without human intervention.