Evolutionary feature synthesis for object recognition

Features represent the characteristics of objects and selecting or synthesizing effective composite features are the key to the performance of object recognition. In this paper, we propose a coevolutionary genetic programming (CGP) approach to learn composite features for object recognition. The knowledge about the problem domain is incorporated in primitive features that are used in the synthesis of composite features by CGP using domain-independent primitive operators. The motivation for using CGP is to overcome the limitations of human experts who consider only a small number of conventional combinations of primitive features during synthesis. CGP, on the other hand, can try a very large number of unconventional combinations and these unconventional combinations yield exceptionally good results in some cases. Our experimental results with real synthetic aperture radar (SAR) images show that CGP can discover good composite features to distinguish objects from clutter and to distinguish among objects belonging to several classes. The comparison with other classical classification algorithms is favorable to the CGP-based approach proposed in this paper.     

A Faithful Distributed Mechanism for Sharing the Cost of Multicast Transmissions

The problem of sharing the cost of multicast transmissions was studied in the past, and two mechanisms, Marginal Cost (MC) and Shapley Value (SH), were proposed to solve it. Although both of them are strategyproof mechanisms, the distributed protocols implementing them are susceptible to manipulation by autonomous nodes. We propose a distributed Shapley Value mechanism in which the participating nodes do not have incentives to deviate from the mechanism specifications. We show that the proposed mechanism is a faithful implementation of the Shapley Value mechanism. We experimentally investigate the performance of the existing and the proposed cost-sharing mechanisms by implementing and deploying them on PlanetLab. We compare the execution time of MC and SH mechanisms for the Tamper-Proof and Autonomous Node models. We also study the convergence and scalability of the mechanisms by varying the number of nodes and the number of users per node. We show that the MC mechanisms generate a smaller revenue compared to the SH mechanisms, and thus, they are not attractive to the content provider. We also show that increasing the number of users per node is beneficial for the systems implementing the SH mechanisms from both computational and economic perspectives.     

Recent advances in friction-stir welding - Process, weldment structure and properties

Friction-stir welding is a refreshing approach to the joining of metals. Although originally intended for aluminium alloys, the reach of FSW has now extended to a variety of materials including steels and polymers. This review deals with the fundamental understanding of the process and its metallurgical consequences. The focus is on heat generation, heat transfer and plastic flow during welding, elements of tool design, understanding defect formation and the structure and properties of the welded materials.     

The occurrence of vulnerable seagrass species Halophila beccarii Ascherson, 1871 from restored mangrove of Koduvally Estuary,south‐west coast of India

The ocean turf grass, Halophila beccarii Ascherson, 1871 was recorded for the first time in the intertidal region of the restored mangrove ecosystem of the Koduvally Estuary on the south‐west coast of India. It was found co‐existing in the shallow muddy area of the mangroves, dominated by mangrove trees of Rhizophora mucronata and Sonneratia alba, and macroalgae, Ulva sp., Enteromorpha sp. and Chaetomorpha sp. The meadow is sparsely scattered with shoots near the mangroves, with a mean density of 720 shoots/m². Details regarding the morphology and hydrographic conditions are described. The occurrence of H. beccarii in the Koduvally estuary is an encouraging sign of improved ecosystem health through mangrove restoration. The development of seagrass meadow in the estuary will improve the sediment stability and water quality. A further comprehensive study on the spatiotemporal variation of this species in the estuary is also recommended for conservation and management of this vulnerable seagrass species.     

Evidence for negative differential resistance and switchable diode effect in multiferroic BiFe0.95Sc0.05O3-based resistive random access memory under doping engineering

Journal of Materials Science: Materials in Electronics - This report explores the influence of scandium (Sc) doping on structural, optical, and resistive switching properties of multiferroic...     

Fabrication and erosion studies of C-SiC composite Jet Vanes in solid rocket motor exhaust

C-SiC composite Jet-Vanes were fabricated using liquid silicon infiltration and tested in a plume of aluminum based solid propellant to study erosion resistance. The Jet-Vanes showed excellent resistance to thermo-oxidative erosion; average linear and mass erosion rates were 1 mm/s and 5 g/s, respectively. Morphology of the eroded surfaces suggests that alumina particles in the plume hit the leading edge of the Jet-Vane, damage it and some material is eroded away. Residual silicon melts and reacts with oxygen to form silica which in turn reacts with SiC matrix. The matrix of SiC, silicon and un-reacted carbon is loosened and erode by high shear forces. Once carbon fibers get exposed directly to the plume, these may be both eroded and oxidized.     

ZrO2 fibers obtained from the halide free synthesis of non-beaded PVA/Zr n-propoxide electrospun fibrous composites

The composite fibers of polyvinyl alcohol (PVA) and zirconium (Zr) n-propoxide were produced by an electrospinning process using the mixed solution of PVA and sol of zirconium n-propoxide. Effects of process parameters, viz. applied voltage, needle to collector distance and flow rate, were studied on the composite fibrous morphology. Bead-free composite fibers, with fiber diameter ranging from 155 nm to 850 nm, were produced with different process parameters. The morphology of the fibers varies significantly with the heat treatment. Heat treatment of the composite fibrous mats results in the removal of PVA, which causes the surface rough while retaining the fibrous morphology. The XRD studies reveal that the structure of PVA free ZrO₂ fibers is tetragonal.