Choice modeling of relook tasks for UAV search missions

This paper addresses human decision-making in supervisory control of a team of unmanned vehicles performing search missions. Previous work has proposed the use of a two-alternative choice framework, in which operators declare the presence or absence of a target in an image. It has been suggested that relooking at a target at some later time can help operators improve the accuracy of their decisions but it is not well understood how - or how well - operators handle this relook task with multiple UAVs. This paper makes two novel contributions in developing a choice model for a search task with relooks. First, we extend a previously proposed queueing model of the human operator by developing a retrial queue model that formally includes relooks. Since real models may deviate from some of the theoretical assumptions made in the requeueing literature, we develop a Discrete Event Simulation (DES) that embeds operator models derived from previous experimental data and present new results in the predicted performance of multi-UAV visual search tasks with relook. Our simulation results suggest that while relooks can in fact improve detection accuracy and decrease mean search times per target, the overall fraction found correctly is extremely sensitive to increased relooks

Design of high gradient, high repetition rate damped C-band rf structures

The gamma beam system of the European Extreme Light Infrastructure–Nuclear Physics project foresees the use of a multibunch train colliding with a high intensity recirculated laser pulse. The linac energy booster is composed of 12 traveling wave C-band structures, 1.8 m long with a field phase advance per cell of 2π=3 and a repetition rate of 100 Hz. Because of the multibunch operation, the structures have been designed with a dipole higher order mode (HOM) damping system to avoid beam breakup (BBU). They are quasiconstant gradient structures with symmetric input couplers and a very effective damping of the HOMs in each cell based on silicon carbide (SiC) rf absorbers coupled to each cell through waveguides. An optimization of the electromagnetic and mechanical design has been done to simplify the fabrication and to reduce the cost of the structures. In the paper, after a review of the beam dynamics issues related to the BBU effects, we discuss the electromagnetic and thermomechanic design criteria of the structures. We also illustrate the criteria to compensate the beam loading and the rf measurements that show the effectiveness of the HOM damping

Surgical treatment of retrosternal extraosseous Ewing Sarcoma in a 6-years old female: a clamshell approach with hemysternectomy and application of a non-crosslinked extracellular matrix

Background Ewing Sarcoma (ES) and Neuroblastoma (NB) belong to a family of tumours of primitive neuroectodermal origin (PNET) that occurs in both bone and soft tissue. Notwithstanding ES and NB are two distinct malignant tumours, sometimes there could be a link between them. Case report We describe a case of an extraosseous ES localized in the retrosternal region and the upper lobe of the right lung, which had been previously treated for NB in a 6 years old female. We treated this case with a clamshell approach which allows, in a one-step surgery, a complete excision of the mass reconstructing the hemysternectomy with a non-crosslinked matrix. Conclusion the clamshell approach is therefore useful to achieve the retrosternal space and the lung with a single surgical access. According to our experience, we consider appropriate to use a non-crosslinked matrix for sternal reconstruction

Concorso Europan per l'area di Hauptstrasse 7, Berlin- Lichtemberg

L'interrogativo di Gropius è stato assunto come sintesi della proposta progettuale formulata, in occasione della partecipazione al concorso Europan 1993, per la sistemazione di un'area su un'ansa della Spree, in una zona di confine tra le due Berlino caratterizzata dalla preenza di insediamenti militari dismessi e di altre infrastrutture di epoca guglielimina. Le richieste formulate dalla municipalità di Berlino contemplavano l'inserimento di una zona residenziale comprensiva di 1200 unità abitative, infrastrutture e servizi comuni, negozi, parcheggi. Il tema generale del concorso ("A casa in città - abitare i quartieri residenziali") poneva inoltre particolare attenzione a nuovi modelli di vita e di abitazione, invitando i partecipanti ad una riflessione sui modi d'uso delle singole unità abitative e degli spazi comuni. La proposta assume come limiti caratterizzanti l'asse forte della Haupstrasse - luogo di scorrimento veloce ai margini della zona centrale - e la riva sinuosa della Spree, inserendo nell'area di progetto case alte, case medie e case basse in un'alternativa tipologica che prevede diversificate categorie di utenti. Le infrastrutturre di servizio sono ospitate parte nel parco, parte nel 'Mittelbau' che si sviluppa sinuoso lungo la Hauptstrasse, anticipando la linea molle del bordo dell'acqua; lungo la facciata, un elemento funzionale (la passerella/stazione di collegamento con l'asse dei servizi pubblici) - intende costituire elemento forte di richiamo (Reklame-Achetektur). Il piano terreno degli edifici, a pilotis, è tutto trasparente, lasciando idealmente libera la visuale dalla strada al fiume, attraverso il verde. Le tipologie abitative sono state studiate ed esemplificate in un abaco che ne illustra caratteristiche e convertibilità