Riparian Vegetation Mapping for Hydraulic Roughness Estimation Using Very High Resolution Remote Sensing Data Fusion

For detailed hydraulic modeling, accurate spatial information of riparian vegetation patterns needs to be derived in automatic fashion. We propose a supervised classification for heterogeneous riparian corridors with a low number of spectrally separate classes using data fusion of a Quickbird image and LIDAR data. The approach considers nine land cover classes including three woody riparian species, brush, cultivated areas, grassland, urban infrastructures, bare soil and water. The classical “stacked vector” approach is adopted for data fusion, while the nonparametric weighted feature-extraction method and the pixel-oriented maximum likelihood algorithm are used for feature-reduction and classification purposes, respectively. We test the approach over a 14-km stretch of the Sieve River (Tuscany Region, Italy). A one-dimensional river modeling is applied over the study reach comparing the results of a classification-derived hydraulic roughness map and a traditional ground-based approach. Despite the complex study reach, the classification method produced encouraging accuracies (OKS = 0.77) and represents a useful tool to delineate application domains of flow resistance models suited to different hydrodynamic patterns (e.g., stiff/flexible vegetation). Hydraulic modeling results showed that the remotely derived floodplain roughness parameterization captures the equivalent Manning coefficient over 20 test cross sections with uncertainty distributions described by low mean and standard deviation values.     

Synthesising CCS bisimulation using graph rewriting

The paper presents a case study on the synthesis of labelled transition systems (ltss) for process calculi, choosing as testbed Milner’s Calculus of Communicating System (ccs).The proposal is based on a graphical encoding: each ccs process is mapped into a graph equipped with suitable interfaces, such that the denotation is fully abstract with respect to the usual structural congruence.Graphs with interfaces are amenable to the synthesis mechanism proposed by Ehrig and König and based on borrowed contexts (bcs), an instance of relative pushouts originally introduced by Milner and Leifer.The bc mechanism allows the effective construction of an lts that has graphs with interfaces as both states and labels, and such that the associated bisimilarity is automatically a congruence.Our paper focuses on the analysis of the lts distilled by exploiting the encoding of ccs processes: besides offering major technical contributions towards the simplification of the bc mechanism, a key result of our work is the proof that the bisimilarity on processes obtained via bcs coincides with the standard strong bisimilarity for ccs.     

Fiber introduction mass spectrometry: fully direct coupling of solid-phase microextraction with mass spectrometry

This work describes the first fully direct coupling of solid-phase microextraction (SPME) with mass spectrometry. An inlet system using a septum as the only interface between the ambient and the high-vacuum mass spectrometer was constructed to allow the introduction of the SPME needle directly into the ionization region of a mass spectrometer. The PDMS-coated fiber was then placed and exposed exactly between the two ionization filaments. Uniform heating of the fiber, efficient thermal desorption, and electron ionization of the analytes were achieved. Using this new analytical technique, here termed fiber introduction mass spectrometry (FIMS), we have been able to detect and quantitate several volatile (VOC) and semivolatile (SVOC) organic chemicals (carbon tetrachloride, benzene, toluene, xylenes, gamma-terpinene, diisoamyl ether, chlorobenzene, and many PAHs) and two herbicides (Sylvex and its methyl ether) from aqueous solutions at low-ppb to ppt levels using either SPME headspace or solution extraction. FIMS shows high sensitivity (ng/L), good reproducibility, and accuracy, providing therefore a simple and effective approach to rapid analysis of VOC and SVOC in various matrixes.     

A Unifying and Rigorous Shape from Shading Method Adapted to Realistic Data and Applications

We propose a new method for the Lambertian Shape From Shading (SFS) problem based on the notion of Crandall-Lions viscosity solution. This method has the advantage of requiring the knowledge of the solution (the surface to be reconstructed) only on some part of the boundary and/or of the singular set (the set of the points at maximal intensity). Moreover it unifies in an unique mathematical formulation the works of Rouy et al. [34, 50], Falcone et al. [21], Prados et al. [46, 48, 49], based on the notion of viscosity solutions and the work of Dupuis and Oliensis [17] dealing with classical solutions and value functions. Also, it allows to generalize their results to the “perspective SFS” problem recently simultaneously introduced in [13,46,55]. While the theoretical part has been developed in [44], in this paper we give some stability results and we describe numerical schemes for the SFS based on this method. We construct provably convergent and robust algorithms. Finally, we apply our SFS method to real images and we suggest some real-life applications.     

Acoustic Emission Damage Assessment of Steel/CFRP Bonds for Rehabilitation

The use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates is increasingly being considered for the rehabilitation of metallic structures. The effective structural monitoring of steel/CFRP adhesive joints is of critical importance to assess the design service performance of the system, which ultimately depends on the bond damage tolerance at the load transfer regions. In the present study laboratory static and fatigue tests were conducted on steel/CFRP skin doubler and double strap joint specimens, which were monitored using the acoustic emission (AE) technique. The characteristics of the AE signals were correlated with the mechanical response of the samples, in order to understand the AE response associated with the accumulation of bond damage. One-dimensional source location was also performed to examine the initiation and the development of the disbond. The results show that AE parameter-based analysis is an effective nondestructive evaluation tool for bond damage detection and area location.     

A trust negotiation system for digital library Web services

A scalable approach to trust negotiation is required in digital library (DL) environments that have large and dynamic user populations. In this paper we introduce Trust-Serv, a model-driven trust negotiation framework for Web services, and show how it can be used to effectively handle trust negotiation in DLs. The framework employs a model for trust negotiation based on state machines, extended with security abstractions. High-level specifications expressed with the state-machine-based model are then translated into formats suitable for automating the trust negotiation process. The proposed framework also supports negotiation policy lifecycle management, an important trait in the dynamic environments that characterize DLs. In particular, we present a set of policy change operations that enable the dynamic evolution of negotiation policies without disrupting ongoing negotiations. The proposed approach has been implemented as a container-centric mechanism that is transparent to the DL and to the developers of DL Web services, simplifying DL development and management as well as enabling scalable deployments.     

Increasing usability when interacting through screen readers

The application of appropriate Web site design and evaluation methods helps to ensure more usable and accessible Web sites. While in the literature guidelines and evaluation methods for accessibility and usability are given and discussed separately, we aim at identifying the relationships between these two concepts, in particular considering usability criteria for accessible Web sites. In this work, we propose a set of such criteria targeted to improving the navigability for a specific group of disabled users, i.e., vision-impaired people. The identification of the eighteen criteria suggested herein was performed through empirical feedback, by which potential issues were identified. Subsequently, a systematic method was developed on the basis of the analysis of potential solutions, resulting in a classification of the criteria according to usability aspects. Some example applications of the proposed criteria to three existing public administration Web sites are discussed.     

Accessing information through multimodal 3D environments: towards universal access

3D environments represent a great opportunity for universal access to information, as they offer an intuitive interaction paradigm, similar to what is experienced by humans in their everyday lives. In spite of that, several 3D interfaces are characterized by poor structures and are hard to navigate. This paper presents the multimodal concept of the Interaction Locus (IL) as a means to give structure to 3D scenes, helping the user to interact with and access information inside them. The concept was initially developed with particular reference to desktop virtual reality (2.5 D virtual reality), but it is general enough to be extended to other contexts, such as real 3D scenes. The final part of this work shows how the IL concept addresses the need for a unified authoring methodology, capable of allowing access to different target user groups from a variety of different devices.