An Investigation into the Use of Physical Modeling for the Prediction of Various Feature Types Visible from Different Viewpoints

Given that aspect graph and viewsphere-based object recognition systems provide a valid mechanism for 3D object recognition of man-made objects, this paper provides a flexible, automated, and general purpose technique for generating the view information for each viewpoint. An advantage of the work is that the technique is unaffected by object complexity because each step makes no assumptions about object shape. The only limitation is that the object can be described by a boundary representation. A second advantage is that the technique can include other feature types such as specularity. The reason for this is that raytracing techniques are used to simulate the physical process of image generation. Hence it is extendible to visible features resulting from effects due to lighting, surface texture, color, transparency, etc. The work described in this paper shows how occluding and nonoccluding edge-based features can be extracted using image processing techniques and then parametrized and also how regions of specularity can be predicted and described. The use of physical modeling enables situations to be simulated and predicted that are intractable for CAD-based methods (e.g., multiscale feature prediction). An advantage of the method is that the interface between the technique and the raytracing module is a rendered image. Should better physics-based image formation algorithms become available, then they could replace the raytracing module with little modification to the rest of the method.     

The science of making ERORS: what error tolerance implies forcapacity in neural networks

Discusses the development of formal protocols for handling error tolerance which allow a precise determination of the computational gains that may be expected. The error protocols are illustrated in the framework of a densely interconnected neural network architecture (with associative memory the putative application), and rigorous calculations of capacity ar shown. Explicit capacities are also derived for the case of feedforward neural network configurations     

Electromechanical and electrothermal behaviours of carbon whisker reinforced elastomer composites

The electromechanical and electrothermal properties of conducting carbon whisker reinforced thermoplastic elastomer (TPE) composites were investigated. The carbon whiskers were derived by a catalytic chemical vapour Deposition (CCVD) process and the TPE was a styrene-ethylene-butylene-styrene (S-EB-S) block copolymer. The electrical resistivity (ϱ) of the composites can be varied either by uniaxial deformation (10¹–10⁸ Ω cm) or by temperature (10¹–10⁵ Ω cm). The temperature-resistivity studies indicated that the resistivity of these composites was influenced by the glass transition temperature (T _g) of the TPE. The ϱ versus 1/T curves exhibited two distinct regimes each with a different negative slope which intersected at the T _g of the elastomer. This was correlated to the T _gof the EB segments in the S-EB-S block copolymer (∼ -50°C) by the dynamic mechanical thermal analysis. Further, uniaxial deformation studies at room temperature (20 °C) demonstrated that the resistivity increased exponentially with the deformation. Processing technique considerations and electron micrographs of the morphology of the composites indicated the formation of polymeric film on the carbon whiskers. Thus, the electrical conduction between carbon whiskers in these highly loaded (33 and 52 vol % fraction) composites occurred through the elastomeric film by electron tunnelling. This is explained on the basis of Mott's electron hopping theory, for conduction through several carbon-polymer-carbon (C-P-C) junctions. Further studies by scanning electron microscopy, dielectric thermal analysis and voltage-current characteristics confirmed this observation. Mechanical and electrical properties of the composites indicated that CCVD carbon whiskers can be used to improve the strength and electrical conductivity of TPEs. The change in resistivity (up to five orders of magnitude) of the composites with respect to the deformation or temperature can find use in electromechanical and electrothermal device applications.     

Dielectric Investigation of NaLiS Nanoparticles Loaded on Alginate Polymer Matrix Synthesized by Single Pot Microwave Irradiation

Sodium lithium sulfide (NaLiS) nanocomposite have been successfully synthesized by using microwave-irradiation (MWI) method. The study suggested that the application of microwave heating is to produce homogeneous and fine NaLiS nanocomposite which were achieved by using the precursors of lithium acetate and thioacetamide in the presence of sodium alginate biopolymer. FTIR is used to identify the structural coordination and functional groups of the prepared nanocomposite. The structural property of NaLiS particles was investigated by XRD. The surface morphology and elemental composition of synthesized material was confirmed by SEM and EDX analyses. The optical property was studied by using UV–Vis spectrophotometer. Thermal stability of as prepared sample was studied by TGA/DTG analysis. Electrical transport studies of the prepared nanocomposite have been analyzed for various temperatures. NaLiS nanocomposite has ionic conductivity of ~?10^?7 S cm^?1 at 35 °C which is six orders of magnitude higher than that of micro sized bulk Li₂S (~?10^?13 S cm^?1).     

Hollow MgNi1.4Zn0.6/CaCu2.79Fe4.21O12 nanocomposite synthesis via ultrasonic high‐temperature spray pyrolysis

In this study, a distinctive hollow MgNi_1.4Zn_0.6/CaCu_2.79Fe_4.21O₁₂ nanocomposite was synthesized for the first time using ultrasonic high‐temperature spray pyrolysis method controlled at 1200°C. Effect of various concentrations (0.01, 0.1, and 1 mol L^?1) of the precursor solution on particle size and crystalline phase of nanocomposites was also analyzed. XRD and SEM results confirmed the difference in the particle size and crystalline pattern of the synthesized nanocomposite arisen due to the difference in concentrations. The results of antibacterial and antioxidant studies showed that the nanocomposites possessed remarkable antibacterial and antioxidant activities. Thus, the prepared hollow MgNi_1.4Zn_0.6/CaCu_2.79Fe_4.21O₁₂ metal oxide nanocomposite via ultrasonic high‐temperature spray pyrolysis can be an excellent material in various biomedical applications.     

Heterogeneous production of Cl2 from particulate chloride: Effects of composition and relative humidity

Reactions initiated by chlorine atoms can enhance the formation of ozone (O₃) and secondary organic aerosol (SOA) in the troposphere. Environmental chamber experiments were conducted to quantify heterogeneous Cl₂ production from NH₄Cl and NaCl particles exposed to O₃ and hydroxyl radicals (?OH). Observations are inconsistent with models of Cl₂ production resulting solely from surface‐mediated reactions of ?OH and suggest that O₃ plays a significant role. The production of Cl₂ increased with relative humidity and decreased in the presence of SOA or nitric oxides (NO_x). Heterogeneous reactive uptake coefficients for the production of Cl₂ from O₃ on pure NH₄Cl ( ) averaged 1.4 ± 1.0 × 10^?3. Cl₂ production was six times more efficient on NH₄Cl aerosol than on NaCl aerosol. Model calculations under atmospheric conditions suggest this heterogeneous Cl₂ production could increase peak daily O₃ concentrations by over 10%. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3151–3158, 2018     

Formal Techniques for Analysing Scenarios using Message Sequence Charts

This paper describes light-weight formal techniques based on Message Sequence Charts (MSCs) for capturing and validating early requirements and design. Our focus is on ease of use in specifying, simulating and validating scenarios, and checking their desired properties efficiently. We discuss how the formalism of High Level Message Sequence Charts (HMSCs or MSC'96), can be used to capture scenarios in use cases, thus enabling the use of tools for analysing them. We then present two formal semantics for HMSCs – an intuitive linear time semantics based on runs, and an operational semantics in terms of a labelled transition system. Next we present a way of describing desired properties of use case scenarios using templates, for validating scenarios with respect to informal requirements. The correctness properties of a collection of MSCs can then be established by efficient algorithms for finding paths in a directed graph representing the precedence relation on the events of the MSCs. We have implemented the operational semantics and the verification algorithms in the form of a simulation and verification tool for analysing scenarios.