116 research outputs found
A phenomenological approach to multisource data integration: Analysing infrared and visible data
A new method is described for combining multisensory data for remote sensing applications. The approach uses phenomenological models which allow the specification of discriminatory features that are based on intrinsic physical properties of imaged surfaces. Thermal and visual images of scenes are analyzed to estimate surface heat fluxes. Such analysis makes available a discriminatory feature that is closely related to the thermal capacitance of the imaged objects. This feature provides a method for labelling image regions based on physical properties of imaged objects. This approach is different from existing approaches which use the signal intensities in each channel (or an arbitrary linear or nonlinear combination of signal intensities) as features - which are then classified by a statistical or evident approach
Positional estimation techniques for an autonomous mobile robot
Techniques for positional estimation of a mobile robot navigation in an indoor environment are described. A comprehensive review of the various positional estimation techniques studied in the literature is first presented. The techniques are divided into four different types and each of them is discussed briefly. Two different kinds of environments are considered for positional estimation; mountainous natural terrain and an urban, man-made environment with polyhedral buildings. In both cases, the robot is assumed to be equipped with single visual camera that can be panned and tilted and also a 3-D description (world model) of the environment is given. Such a description could be obtained from a stereo pair of aerial images or from the architectural plans of the buildings. Techniques for positional estimation using the camera input and the world model are presented
Understanding virtual world usage: A multipurpose model and empirical testing
This paper investigates the role of boundary objects in the interdisciplinary collaborative processes
found in computer games development. It draws on data from an in-depth case study in a computer
games studio that explores boundary objects in relation to the compelling, sensory and entertainmentcentred game-playing practices that inform computer games design and development. Sensory user
experience and aesthetic considerations – of primary importance in computer games development –
are becoming increasingly significant in the design and development of many other kinds of software
and information systems. For this reason developments in the design and production of computer
games have wider implications for other software and information systems settings and provide
valuable insights into processes of collaboration that bridge cultural and aesthetic as well as technical
forms of expertise. The paper seeks to provide insights into how objects contribute to such
collaboration, with attention focusing especially on how game developers devise objects that span
boundaries and draw on these in their collaboration. Through its focus on the material production and
practices of computer games development, the research presented also seeks to contribute to the
theoretical treatment of interdisciplinary collaborative working in software design and development
via a critical assessment of the concept of boundary objects in the setting being studied
Determining the 3-D structure and motion of objects using a scanning laser range sensor
In order for the EVAHR robot to autonomously track and grasp objects, its vision system must be able to determine the 3-D structure and motion of an object from a sequence of sensory images. This task is accomplished by the use of a laser radar range sensor which provides dense range maps of the scene. Unfortunately, the currently available laser radar range cameras use a sequential scanning approach which complicates image analysis. Although many algorithms have been developed for recognizing objects from range images, none are suited for use with single beam, scanning, time-of-flight sensors because all previous algorithms assume instantaneous acquisition of the entire image. This assumption is invalid since the EVAHR robot is equipped with a sequential scanning laser range sensor. If an object is moving while being imaged by the device, the apparent structure of the object can be significantly distorted due to the significant non-zero delay time between sampling each image pixel. If an estimate of the motion of the object can be determined, this distortion can be eliminated; but, this leads to the motion-structure paradox - most existing algorithms for 3-D motion estimation use the structure of objects to parameterize their motions. The goal of this research is to design a rigid-body motion recovery technique which overcomes this limitation. The method being developed is an iterative, linear, feature-based approach which uses the non-zero image acquisition time constraint to accurately recover the motion parameters from the distorted structure of the 3-D range maps. Once the motion parameters are determined, the structural distortion in the range images is corrected
View-Invariant Regions and Mobile Robot Self-Localization
This paper addresses the problem of mobile robot self-localization
given a polygonal map and a set of observed edge segments. The
standard approach to this problem uses interpretation tree search with
pruning heuristics to match observed edges to map edges. Our approach
introduces a preprocessing step in which the map is decomposed into
'view-invariant regions' (VIRs). The VIR decomposition captures
information about map edge visibility, and can be used for a variety of
robot navigation tasks. Basing self-localization
search on VIRs greatly reduces the branching factor of the search
tree and thereby simplifies the search task. In this paper we define
the VIR decomposition and give algorithms for its computation and for
self-localization search. We present results of simulations comparing
standard and VIR-based search, and discuss the application of the VIR
decomposition to other problems in robot navigation
CONTROLLED DELIVERY OF ANTIRETROVIRAL DRUG-LOADED CROSS-LINKED MICROSPHERES BY IONIC GELATION METHOD
Objective: Lamivudine (LVD) is a nucleoside reverse transcriptase inhibitor originally developed as an antiretroviral drug and primarily used in thetreatment of most common chronic disease of the planet, acquired immune deficiency syndrome and hepatitis B. The main objective of the study is todevelop controlled drug delivery system to increase the efficacy of antiretroviral drug, LVD against human immunodeficiency virus infections.Methods: The microencapsulation of LVD in gelatin microspheres was carried out by cross-linking process with glutaraldehyde saturated tolueneusing ionic-gelation method. The prepared microspheres were evaluated for particle size analysis, % yield value, % drug content, drug entrapmentefficiency, scanning electron microscopy for surface morphology, swelling index, accelerated stability studies, Fourier transform infrared radiationspectroscopy (FT-IR) and differential scanning calorimetry (DSC) for polymer drug compatibility, in vitro dissolution efficiency and release kineticstudies.Results: The obtained microspheres showed very smooth surface and exhibited regular spherical geometry due to higher crosslinking density. FT-IRand DSC revealed the absence of drug polymer interactions. The percentage yield, entrapment efficiency and drug content for F6 LVD microsphereswas found to be 79.31%, 65.55% and 96.25% respectively. The particle size was ranged from 34.61% to 51.45 μm sizes and in vitro release profileshowed that cross-linking density of gelatin microspheres effectively controlled the release of LVD.Conclusion: The findings of our investigation demonstrated that F6 of gelatin-LVD microspheres had good controlled release profile with maximumentrapment efficiency and prolonged drug release for 24 hrs or longer and this formulation would be capable of overcoming the drawbacks andlimitations of LVD conventional dosage forms.Keywords: Lamivudine, Microspheres, Controlled release, Gelatin, Fourier transform infrared, Differential scanning calorimetry, In vitro releasekinetics
Understanding the selective etching of electrodeposited ZnO nanorods
ZnO nanotubes were prepared by selective dissolution of electrodeposited nanorods. The effect of solution pH, rod morphology, and chloride ion concentration on the dissolution mechanism was studied. The selective etching was rationalized in terms of the surface energy of the different ZnO crystal faces and reactant diffusion. The nanorod diameter and chloride concentration are the most influential parameters on the dissolution mechanism because they control homogeneous dissolution or selective etching of the (110) and (002) surfaces. Bulk solution pH only has an effect on the rate of dissolution. By accurate control of the dissolution process, the nanomorphology can be tailored, and the formation of rods with a thin diameter (10-20 nm), cavity, or ultra-thin-walled tubes (2-5 nm) can be achieved
Automatic Tachycardia Recognition
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73320/1/j.1540-8159.1984.tb04948.x.pd
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Watching mesoporous metal films grow during templated electrodeposition with in situ SAXS
In this paper, we monitor the real-time growth of mesoporous platinum during electrodeposition using small-angle X-ray scattering (SAXS). Previously, we have demonstrated that platinum films featuring the ‘single diamond’ (Fd3m) morphology can be produced from ‘double diamond’ (Pn3m) lipid cubic phase templates; the difference in symmetry provides additional scattering signals unique to the metal. Taking advantage of this, we present simultaneous in situ SAXS/electrochemical measurement as the platinum nanostructures grow within the lipid template. This measurement allows us to correlate the nanostructure appearance with the deposition current density and to monitor the evolution of the orientational and lateral ordering of the lipid and platinum during deposition and after template removal. In other periodic metal nanomaterials deposited within any of the normal topology liquid crystal, mesoporous silica or block copolymer templates previously published, the template and emerging metal have the same symmetry, so such a study has not been possible previously
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