Rawseeds ground truth collection systems for indoor self-localization and mapping

A trustable and accurate ground truth is a key requirement for benchmarking self-localization and mapping algorithms; on the other hand, collection of ground truth is a complex and daunting task, and its validation is a challenging issue. In this paper we propose two techniques for indoor ground truth collection, developed in the framework of the European project Rawseeds, which are mutually independent and also independent on the sensors onboard the robot. These techniques are based, respectively, on a network of fixed cameras, and on a network of fixed laser scanners. We show how these systems are implemented and deployed, and, most importantly, we evaluate their performance; moreover, we investigate the possible fusion of their outputs.     

Computational support to record and re-experience visits

Information technology research has mainly focussed on supporting visitors with guides, whilst a lot of opportunities for the development of technology for collecting, manipulating and re-travelling through material from the visits remain unexplored. On the basis of observations from a specific setting, we have developed prototype technology to combine multimedia content with position information. In particular, we developed mobile support to record and organise multimedia using the walked path in order to preserve more of the experience of the visit. We created tools to edit and store multimedia paths. Additional components make it possible to configure a mixed-media environment to navigate a multimedia path, using such physical interfaces as gesturing, and link the recorded media to other artefacts. When discussing field observations of current practices and prototype trials, we investigate what kind of functionality is needed to support the whole activity of collecting, manipulating and playing multimedia content in combination with position information.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in the air of Seveso,Italy, 26 years after the explosion

This study reports the current levels of polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in air at Seveso, where an explosion in a 2,4,5,-trichlorophenol production reactor occurred 26 years ago. The aims were to assess if residues of the 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) released during the accident and still present in soil could contaminate the above air and to investigate other potential sources in the area. Long-term air collection was carried out in zones A and B in Seveso and in a reference location in Milan, and samples were analyzed for PCDD and PCDF concentrations by gas chromatography-mass spectrometry (GC-MS). Experimental results showed that no important contribution to the air concentrations is due to the soil contamination and that contemporary sources essentially control the atmospheric burden of PCDDs and PCDFs in the Seveso area. The theoretical release of 2,3,7,8-TCDD from the soils of zones A and B of Seveso was calculated using the SoilFug model. In the worst case, the model simulated an enrichment in atmospheric 2,3,7,8-TCDD concentrations of 4 and 22% for zones A and B, respectively. The investigation of the potential emission sources in the area indicated that combustion of wood residues from furniture factories may be an additional local source of PCDDs and PCDFs.     

Quantum Erasure of Decoherence

We consider the classical algebra of observables that are diagonal in a given orthonormal basis, and define a complete decoherence process as a completely positive map that asymptotically converts any quantum observable into a diagonal one, while preserving the elements of the classical algebra. For quantum systems in dimension two and three any decoherence process can be undone by collecting classical information from the environment and using such an information to restore the initial system state. As a relevant example, we illustrate the quantum eraser of Scully et al. [Nature 351, 111 (1991)] as an example of environment-assisted correction, and present the generalization of the eraser setup for d-dimensional systems. Presented at the 38th Symposium on Mathematical Physics “Quantum Entanglement & Geometry”, Toruń, June 4–7, 2006.     

The Effects of Microstructure Heterogeneities and Casting Defects on the Mechanical Properties of High-Pressure Die-Cast AlSi9Cu3(Fe) Alloys

Detailed investigations of the salient microstructural features and casting defects of the high-pressure die-cast (HPDC) AlSi9Cu3(Fe) alloy are reported. These characteristics are addressed to the mechanical properties and reliability of separate HPDC tensile bars. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes throughout the tensile specimen. The results indicate that the die-cast microstructure consists of several microstructural heterogeneities such as positive eutectic segregation bands, externally solidified crystals (ESCs), cold flakes, primary Fe-rich intermetallics (sludge), and porosities. In addition, it results that sludge particles, gas porosity, as well as ESCs, and cold flakes are concentrated toward the casting center while low porosity and fine-grained structure is observed on the surface layer of the castings bars. The local variation of the hardness along the cross section as well as the change of tensile test results as a function of gage diameter of the tensile bars seem to be ascribed to the change of porosity content, eutectic fraction, and amount of sludge. Further, this behavior reflects upon the reliability of the die-cast alloy, as evidenced by the Weibull statistics.     

Bicyclo‐orthoester as a low‐shrinkage additive in cationic UV curing

A commercially available bicyclo‐orthoester (BOE) was used as low‐shrinkage additive for cationic UV curing of epoxy resins. A high reactivity of BOE by ring‐opening homopolymerization has been observed under cationic UV curing conditions. The BOE and trimethylolpropane triglycidyl ether monomers are compatible and give rise to a cured copolymeric network, under UV irradiation, with a flexibilization increase by increasing the BOE content in the photocurable formulation. Shrinkage after photopolymerization shows a linear reduction by increasing the BOE content in the photocurable formulation; a volume expansion upon polymerization is reached in the presence of 50 wt% of the additive. Copyright © 2007 Society of Chemical Industry