Air‐ground Matching: Appearance‐based GPS‐denied Urban Localization of Micro Aerial Vehicles

In this paper, we address the problem of globally localizing and tracking the pose of a camera‐equipped micro aerial vehicle (MAV) flying in urban streets at low altitudes without GPS. An image‐based global positioning system is introduced to localize the MAV with respect to the surrounding buildings. We propose a novel air‐ground image‐matching algorithm to search the airborne image of the MAV within a ground‐level, geotagged image database. Based on the detected matching image features, we infer the global position of the MAV by back‐projecting the corresponding image points onto a cadastral three‐dimensional city model. Furthermore, we describe an algorithm to track the position of the flying vehicle over several frames and to correct the accumulated drift of the visual odometry whenever a good match is detected between the airborne and the ground‐level images. The proposed approach is tested on a 2 km trajectory with a small quadrocopter flying in the streets of Zurich. Our vision‐based global localization can robustly handle extreme changes in viewpoint, illumination, perceptual aliasing, and over‐season variations, thus outperforming conventional visual place‐recognition approaches. The dataset is made publicly available to the research community. To the best of our knowledge, this is the first work that studies and demonstrates global localization and position tracking of a drone in urban streets with a single onboard camera.     

On the Ontological Status of Plans and Norms

This article describes an ontological model of norms. The basic assumption is that a substantial part of a legal system is grounded on the concept of agency. Since a legal system aims at regulating a society, then its goal can be achieved only by affecting the behaviour of the members of the society. We assume that a society is made up of agents (which can be individuals, institutions, software programs, etc.), that agents have beliefs, goals and preferences, and that they commit to intentions in order to choose a line of behaviour. The role of norms, within a legal system, is to specify how and when the chosen behaviour agrees with the basic principles of the legal system. In this article, we show how a model based on plans can be the basis for the ontological representation of norms, which are expressed as constraints on the possible plans an agent may choose to guide its behaviour. Moreover, the paper describes how the proposed model can be linked to the upper level of a philosophically well-founded ontology (DOLCE); in this way, the model is set in a wider perspective, which opens the way to further developments.     

Evaluating and improving the content access in KAD

We analyze in detail the content retrieval process in kad. kad implements content search (publish and retrieval) functions that use the Kademlia Distributed Hash Table for content routing. Node churn is quite common in peer-to-peer systems and results in information loss and stale routing table entries. To deal with node churn, kad issues parallel route requests and publishes multiple redundant copies of each piece of information. We identify the key design parameters in kad and present an analytical model to evaluate the impact of changes in the values of these parameters on the overall lookup latency and message overhead. Extensive measurements of the lookup performance using an instrumented client allow us to validate the model. The overall lookup latency is in most cases 5 s or larger. We elucidate the cause for such high lookup latencies and propose an improved scheme that significantly decreases the overall lookup latency without increasing the overhead.     

Labyrinth 3D. Cultural archetypes for exploring media archives

Since the advent of the World Wide Web, online media archives have changed their audience from a restricted number of professionals and amateurs to the general public. This shift is not without consequences: if, on the one side, it represents an important opportunity for archives to engage in a dialogue with a larger audience, on the other side, it advocates novel forms of access that go beyond the highly specialized models underlying traditional access tools. In this paper, we propose to use 3-D graphics for designing novel tools of exploratory search in cultural heritage archives. Our approach has been deployed as an online virtual environment where the user can navigate the meaning relations over the items in the archive. Targeted at cultural heritage, the application, called Labyrinth 3D, relies on the use of cultural archetypes to inform the conceptualization of the archive and the creation of the virtual environment, with the goal of engaging the user in the exploration of the archive through the creation of personal paths.     

Polychaete-Like Undulatory Robotic Locomotion in Unstructured Substrates

A biological paradigm of versatile locomotion and effective motion control is provided by the polychaete annelid worms, whose motion adapts to a large variety of unstructured environmental conditions (sand, mud, sediment, water, etc.), and could thus be of interest to replicate by robotic analogs. Their locomotion is characterized by the combination of a unique form of tail-to-head body undulations (opposite to snakes and eels), with the rowing-like action of numerous lateral appendages distributed along their long segmented body. Focusing on the former aspect of polychaete locomotion, computational models of crawling and swimming by such tail-to-head body undulations have been developed in this paper. These are based on the Lagrangian dynamics of the system and on resistive models of its interaction with the environment, and are used for simulation studies demonstrating the generation of undulatory gaits. Several biomimetic robotic prototypes have been developed, whose undulatory actuation achieves propulsion on sand and other granular unstructured environments. Extensive experimental studies demonstrate the feasibility of robot propulsion by tail-to-head body undulations in such environments, as well as the agreement of its qualitative and quantitative characteristics to the predictions of the corresponding computational models.     

The canonical processes of a dramatized approach to information presentation

This paper describes the application “Carletto the spider” in terms of the mapping with the canonical processes of media production. “Carletto the spider” is a character-based guide to a historical site and implements the Dramatour approach for the design of drama-based interactive presentations. Dramatization makes presentations more engaging, thus improving the reception of the content by the user. The major technical issue of the approach is the segmentation of the presentation into audiovisual units that are edited on-the-fly in a way that guarantees dramatic continuity while adapting to the user response. We describe the workflow of the application and its mapping to the canonical processes of media production, envisaging possible standardizations for the application portability.     

Hypomagnesemia and smooth muscle contractility: diffuse esophageal spasm in an old female patient

The aim of this paper is to describe and discuss, on the basis of the available literature, the case of an old female patient, admitted to our university hospital because of a severe dysphagia for solid foods, in whom laboratory data showed a marked hypomagnesemia. She reported a long history (20 years) of allergic bronchial asthma treated with theophylline. Esophagography evidenced a disorder of esophagus motility with diffuse multiple spasm, reminiscent of the 'corkscrew esophagus'. A link with the severe hypomagnesemia (Mg 1.1 mEq/l, normal range 1.6-2.1) was suspected, and a therapy with oral pidolate of Mg (1.5 g/twice a day) was started and continued for 4 months. This was associated with a slow progressive normalization of the Mg plasma level and reverted radiographic esophageal findings with disappearance of dysphagia. Mg is an important element for health and disease, and today Mg deficiency in man has become an accepted medical problem which might complicate many diseases. Neuromuscular disorders, as laryngeal spasm, are recognized complications of hypomagnesemia, but until now only 1 case of motor esophageal disorder associated with a low Mg plasma level was briefly reported in the literature, even if dysphagia is generally included in the symptomatological pattern of hypomagnesemia. Our observation of a severe form of esophageal spasm, associated with hypomagnesemia, in an aged female patient underlines the pathophysiological meaning of the plasma Mg level and suggests the need for routine Mg determination in the clinical setting.     

Induction motor drive parameters identification

Two online identifiers of the rotor parameters of the field-oriented (FO) induction motor drive are presented in this paper, The synthesis procedure of the identifiers is based on the model reference adaptive control (MRAC) system theory. An appropriate choice of the reference model allows building a Lyapunov function by means of which the updating law of the rotor time constant can be found. A higher order identifier is also synthesized using hyperstability approach. It allows the simultaneous identification of two rotor parameters. The parameters' convergence is assured thanks to the persistent exciting propriety of the input vector of the identifier, represented by the stator current. Experimental results conducted on an FO-controlled drive, using a digital signal processor (DSP)-based system (TMS320C31), having 40-MHz clock frequency, show the convergent trajectories of the parameters and of the state errors under various significant steady state and transient operating conditions and for different values of the adaption gains. The results show the satisfactory behavior of the proposed identification algorithms     

Nanotechnology Meets Oncology: A Perspective on the Role of the Personalized Nanoparticle-Protein Corona in the Development of Technologies for Pancreatic Cancer Detection

In recent years nanotechnology has opened exciting opportunities in the struggle against cancer. In 2007 Dawson and coworkers demonstrated that nanomaterials exposed to biological fluids are coated with plasma proteins that form the so-called “protein corona”. A few years later our joint research team made of physicists, chemists, biotechnologists, surgeons, oncologists, and bioinformaticians introduced the concept of “personalized protein corona” and demonstrated that it is unique for each human condition. This concept paved the way for the development of nano-enabled blood (NEB) tests for the diagnosis of pancreatic ductal adenocarcinoma (PDAC). These studies gave an impetus to serious work in the field that came to maturity in the late 2010s. In this special issue, we provide the reader with a comprehensive overview of the most significant discoveries of our research team in the field of PDAC detection. We focus on the main achievements with an emphasis on the fundamental aspects of this arena and how they shaped the integration of different scientific backgrounds towards the development of advanced diagnostic technologies. We conclude the review by outlining future perspectives and opportunities to transform the NEB tests into a reliable clinical diagnostic technology for early diagnosis, follow-up, and management of PDAC patients.     

Application of an algebraic tool to fast analysis and synthesis ofconformal printed antennas

The analysis and synthesis of conformal printed antennas on conical surfaces are investigated. The theoretical model is based on the cavity model and the concept of dynamic permittivity to take into account the thickness and the fringing field effects. The originality comes from the use of a computer algebra system to generate the polynomial expression of the zeros of characteristic equations and the analytical relation between the half-angle of the cone and the order of the associated Legendre functions. Fast and accurate expressions for the resonance frequency are given for a rectangular radiating element operating in TM₁₀ and TM₀₁ modes. This model is easily included in a CAD package. Very good agreement is observed between numerical results and experiments