Effect of ageing on the morphology and creep and recovery of polymer-modified bitumens

Polymer additives are used to improve the properties of road bitumens including their oxidative resistance. However, their usage as anti-oxidative materials remains relatively unclear. This study aims to investigate the changes in the morphology and the rheological response of polymer modified bitumens used in road pavement construction caused by ageing. An elastomer (radial styrene butadiene styrene, SBS) and a plastomer (ethyl vinyl acetate, EVA) polymer were mixed with one base bitumen at three polymer concentrations. The bitumens were RTFO and PAV aged. The morphology of the bitumens was captured by fluorescence microscopy while the rheological properties were measured by means of the multiple stress creep and recovery (MSCR) test. The results show that the morphology of the SBS modified bitumen degrades with ageing as a function of polymer concentration and dispersion, with higher dispersion being more resistant. The morphology of the EVA modified bitumen has a low ageing susceptibility irrespective of polymer concentration. The MSCR response of EVA modified bitumens does not differ from that found for unmodified bitumen, where the hardening produces a decrease in the non-recoverable compliance. In the case of SBS modified bitumen, the degradation of the polymer backbone affects the bitumen hardening as much as the polymer phase dispersed and networked in the bitumen phase. Furthermore, in the case of the elastomer, the average percent recovery is in agreement with the variation of the morphology with ageing. Therefore, the use of the average percent recovery as a valuable rheological index of the integrity of the polymer network can be advocated.     

Physician-patient interactions: a comparison of analysis systems

OBJECTIVE: The medical interview has important diagnostic and therapeutic functions and requires the integration of doctor-centred and patient-centred interviewing techniques to collect accurate and complete biopsychosocial data from the patient. Analysis of the interaction between patient and doctors which occur during the medical interview allow to evaluate physicians' interview techniques and to eventually improve them. OBJECTIVE: 1. To review different Interaction Analysis Systems (IAS) used to describe doctor-patient communication in terms of clinical relevance, observational strategy, reliability and behavioural and verbal contents. 2. To critically evaluate these IASs on the basis of their relevant research outcomes. METHOD: Previous reviews on interaction and keywords for Medline research (HealthGate) listed above were utilised to collect the relevant literature. RESULTS: Seventeen classification systems were identified and ten were discussed in a chronological order. Starting from a general sociological or psycholinguistic approach, the IASs over the years have became more specific and detailed, focusing more on the medical interview and on specific topics, such as cancer or hospital medical consultations. CONCLUSIONS: When studying interactions in general practice medicine, it is important to define the significant units of interaction which allow to identify a "patient-centred approach", since this is relevant not only for obtaining reliable and complete medical and social data, but also for the recognition of patients with emotional disorders and their correct diagnosis. Listening to the patient and facilitating the expression of emotions is an important aspect of patient education too, as patients learn that talking about psychological problems to their physician is appropriate and may be therapeutic.     

The design of a collaborative interface for narration to support reconciliation in a conflict

This paper is about the development of a face-to-face collaborative technology to support shifting attitudes of participants in conflict via a narration task. The work is based on two cultural elements: conflict resolution theory and the design of a collaboration enforcing interface designed specifically for the task. The general claim is that participants may achieve a greater understanding of and appreciation for the other’s viewpoint under conditions that support partaking in a tangible joint task and creating a shared narration. Specifically, a co-located interface for producing a joint narration as a tool for favoring reconciliation is presented and discussed. The process based on this technology implicitly includes classical steps in conflict resolution approaches, such as escalation and de-escalation. Our goal is to show that this interface is effective and constitutes an alternative to a typical face-to-face moderated discussion.     

Enhancing social communication of children with high-functioning autism through a co-located interface

This study evaluated the effectiveness of a 3-week intervention in which a co-located cooperation enforcing interface, called StoryTable, was used to facilitate collaboration and positive social interaction for six children, aged 8–10 years, with autistic spectrum disorder (ASD). The intervention focused on exposing pairs of children to an enforced collaboration paradigm while they narrated a story. Pre- and post-intervention tasks included a “low technology” version of the storytelling device and a non storytelling play situation using a free construction game. The outcome measure was a structured observation scale of social interaction. Results demonstrated progress in three areas of social behaviors. First, the participants were more likely to initiate positive social interaction with peers after the intervention. Second, the level of shared play of the children increased from the pre-test to the post-test and they all increased the level of collaboration following the intervention. Third, the children with ASD demonstrated lower frequencies of autistic behaviors while using the StoryTable in comparison to the free construction game activity. The implications of these findings are discussed in terms of the effectiveness of this intervention for higher functioning children with ASD.     

Approximate NMPC for vehicle stability: Design,implementation and SIL testing

In this paper, Nonlinear Model Predictive Control is used to improve vehicle stability and handling by means of a rear active differential. In order to allow on-line control computations within the required sampling time, a Set Membership approximation of the designed controller is employed. The real applicability and effectiveness of such a technique, as well as the improvement over an existing control approach based on Internal Model Control, is shown through the implementation on a commercial embedded device with limited computational capacity and the testing via software-in-the-loop simulations of demanding maneuvers, using an accurate nonlinear vehicle model.     

Optimizing model predictive control of the chromatographic multi-column solvent gradient purification (MCSGP) process

The multi-column solvent gradient purification (MCSGP) process is a new continuous chromatographic process specifically designed for the purification of proteins and peptides. Due to its countercurrent purification principle, the performance increase with respect to the batch process can be up to 10× in productivity and even more at higher yields. Various successful applications of the MCSGP-technology have been reported, e.g. the purification of monoclonal antibodies from high-titer supernatants with ion-exchange resins and the purification of polypeptides.However, optimal MCSGP operation is a challenge and the current practice is to operate the MCSGP units at sub-optimal conditions to guarantee robustness and improve the separation performance by tuning the operating conditions off-line. As a result, systematic optimization tools like control and automation of MCSGP is of great interest in order to exploit the full economic potential of this process. An automatic control algorithm for MCSGP units that guarantees an optimal, robust operation with product purities in specification is a challenging problem because of the uncertainty related to the adsorption behavior of the mixture to be separated and the complex dynamics involved in this process, i.e. its cyclic and hybrid nature due to the inlet/outlet port switching with strong nonlinearities and delays in the feedback information.In this work, a control algorithm based on previous work for control of continuous chromatographic process is developed for the MCSGP-technology. The flow rates as well as the modifier gradients have been chosen as manipulated variables. The suitability of the controller is proven by means of two simulation case studies, i.e. the separation of monoclonal antibody variants and of a mixture of peptides.     

Matching Trajectories between Video Sequences by Exploiting a Sparse Projective Invariant Representation

Identifying correspondences between trajectory segments observed from nonsynchronized cameras is important for reconstruction of the complete trajectory of moving targets in a large scene. Such a reconstruction can be obtained from motion data by comparing the trajectory segments and estimating both the spatial and temporal alignments. Exhaustive testing of all possible correspondences of trajectories over a temporal window is only viable in the cases with a limited number of moving targets and large view overlaps. Therefore, alternative solutions are required for situations with several trajectories that are only partially visible in each view. In this paper, we propose a new method that is based on view-invariant representation of trajectories, which is used to produce a sparse set of salient points for trajectory segments observed in each view. Only the neighborhoods at these salient points in the view--invariant representation are then used to estimate the spatial and temporal alignment of trajectory pairs in different views. It is demonstrated that, for planar scenes, the method is able to recover with good precision and efficiency both spatial and temporal alignments, even given relatively small overlap between views and arbitrary (unknown) temporal shifts of the cameras. The method also provides the same capabilities in the case of trajectories that are only locally planar, but exhibit some nonplanarity at a global level.     

SkelTre

Terrestrial laser scanners capture 3D geometry of real world objects as a point cloud. This paper reports on a new algorithm developed for the skeletonization of a laser scanner point cloud. The skeletonization algorithm proposed in this paper consists of three steps: (i) extraction of a graph from an octree organization, (ii) reduction of the graph to a skeleton, and (iii) embedding of the skeleton into the point cloud. For these three steps, only one input parameter is required. The results are validated on laser scanner point clouds representing 2 classes of objects; first on botanic trees as a special application and secondly on popular arbitrary objects. The presented skeleton found its first application in obtaining botanic tree parameters like length and diameter of branches and is presented here in a new, generalized version. Its definition as Reeb Graph, proofs the usefulness of the skeleton for applications like shape analysis. In this paper we show that the resulting skeleton contains the Reeb Graph and investigate the practically relevant parameters: centeredness and topological correctness. The robustness of this skeletonization method against undersampling, varying point density and systematic errors of the point cloud is demonstrated on real data examples.     

Using Bounded Model Checking for Coverage Analysis of Safety-Critical Software in an Industrial Setting

Testing and Bounded Model Checking (BMC) are two techniques used in Software Verification for bug-hunting. They are expression of two different philosophies: testing is used on the compiled code and it is more suited to find errors in common behaviors, while BMC is used on the source code to find errors in uncommon behaviors of the system. Nowadays, testing is by far the most used technique for software verification in industry: it is easy to use and even when no error is found, it can release a set of tests certifying the (partial) correctness of the compiled system. In the case of safety critical software, in order to increase the confidence of the correctness of the compiled system, it is often required that the provided set of tests covers 100% of the code. This requirement, however, substantially increases the costs associated to the testing phase, since it often involves the manual generation of tests. In this paper we show how BMC can be productively applied to the Software Verification process in industry. In particular, we show how to productively use a Bounded Model Checker for C programs (CBMC) as an automatic test generator for the Coverage Analysis of Safety Critical Software. In particular, we experimented CBMC on a subset of the modules of the European Train Control System (ETCS) of the European Rail Traffic Management System (ERTMS) source code, an industrial system for the control of the traffic railway, provided by Ansaldo STS. The Code of the ERTMS/ETCS, with thousands of lines, has been used as trial application with CBMC obtaining a set of tests satisfying the target 100% code coverage, requested by the CENELEC EN50128 guidelines for software development of safety critical systems. The use of CBMC for test generation led to a dramatic increase in the productivity of the entire Software Development process by substantially reducing the costs of the testing phase. To the best of our knowledge, this is the first time that BMC techniques have been used in an industrial setting for automatically generating tests achieving full coverage of Safety-Critical Software. The positive results demonstrate the maturity of Bounded Model Checking techniques for automatic test generation in industry.     

Estimation of land subsidence in deltaic areas through differential SAR interferometry: the Po River Delta case study (Northeast Italy)

ABSTRACT

River deltas are very complex environments vulnerable to flooding. Most of the world’s deltas are facing the immediate threat of land subsidence that jeopardizes the safety of millions of people worldwide. In Italy, the Po River Delta (PRD) (Northeast Italy) is an area historically affected by high rate of subsidence due to natural and anthropic factors. Even if the subsidence rates remarkably reduced during the last three decades, this process continues to be alarming in particular in low-lying sectors and along the coastline, where the loss of elevation, combined with the sea-level rise, increases the risk related to flooding. In this study, we monitored the subsidence affecting the entire PRD area with advanced differential interferometric synthetic aperture radar (A-DInSAR) techniques applied to three C-band SAR data sets acquired by the European Remote Sensing satellites, Environmental Satellite, and Sentinel-1A satellite in the last 25 years (from 1992 to 2017). The results of the interferometric processing, consisting of both mean velocity and displacement time series along the satellite line of sight, validated by comparison with levelling and global positioning system measurements, show increasing subsidence moving from the inland to the coastline, with maximum deformation velocities, for the most recent data, in the order of ?30 mm year^?1. In particular, many embankments near the coastal area are affected by high values of subsidence, which increase the flooding hazard of the entire deltaic territory. This work shows the importance of adopting A-DInSAR techniques to update the knowledge of the extent and rates of deformation of subsiding areas in low-lying territories such as river deltas. The outputs of such monitoring can be of primary importance for the future protection of the territory and the flooding risk mitigation.