7,820 research outputs found
Understanding expertise in surgical gesture by means of Hidden Markov Models
Minimally invasive surgery (MIS) has became very widespread in the last ten years. Due to the difficulties encountered by the surgeons to learn and manage this technique, a huge importance has the improvement of training procedures, the improvement of surgical instrumentation and the robotic automation of surgical gesture. All these purposes require the analysis of surgical performance with the aim to understand it and to define what is expertise in surgical gesture. In this paper for the first time the Hidden Markov Models (HMMs) are used as a tool for the understanding of surgical performance and of the human factors that characterize it. In our experiments we used position data concerning the tools movements during exercises performed on a surgical simulator. Using Hidden Markov theory, we create a model of the expert surgeon performance able to evaluate surgical capability and to distinguish between expert and non-expert surgeons. By analyzing the trained model of the expert surgeon performance we show that it is possible to deduce information about features characterizing the surgical expertise
Hierarchical Self-Assembly of Halogen-Bonded Block Copolymer Complexes into Upright Cylindrical Domains
Self-assembly of block copolymers into well-defined, ordered arrangements of chemically distinct domains is a reliable strategy for preparing tailored nanostructures. Microphase separation results from the system, minimizing repulsive interactions between dissimilar blocks and maximizing attractive interactions between similar blocks. Supramolecular methods have also achieved this separation by introducing small-molecule additives binding specifically to one block by noncovalent interactions. Here, we use halogen bonding as a supramolecular tool that directs the hierarchical self-assembly of low-molecular-weight perfluorinated molecules and diblock copolymers. Microphase separation results in a lamellar-within-cylindrical arrangement and promotes upright cylindrical alignment in films upon rapid casting and without further annealing. Such cylindrical domains with internal lamellar self-assemblies can be cleaved by solvent treatment of bulk films, resulting in separated and segmented cylindrical micelles stabilized by halogen-bond-based supramolecular crosslinks. These features, alongside the reversible nature of halogen bonding, provide a robust modular approach for nanofabricatio
Internet of robotic things : converging sensing/actuating, hypoconnectivity, artificial intelligence and IoT Platforms
The Internet of Things (IoT) concept is evolving rapidly and influencing newdevelopments in various application domains, such as the Internet of MobileThings (IoMT), Autonomous Internet of Things (A-IoT), Autonomous Systemof Things (ASoT), Internet of Autonomous Things (IoAT), Internetof Things Clouds (IoT-C) and the Internet of Robotic Things (IoRT) etc.that are progressing/advancing by using IoT technology. The IoT influencerepresents new development and deployment challenges in different areassuch as seamless platform integration, context based cognitive network integration,new mobile sensor/actuator network paradigms, things identification(addressing, naming in IoT) and dynamic things discoverability and manyothers. The IoRT represents new convergence challenges and their need to be addressed, in one side the programmability and the communication ofmultiple heterogeneous mobile/autonomous/robotic things for cooperating,their coordination, configuration, exchange of information, security, safetyand protection. Developments in IoT heterogeneous parallel processing/communication and dynamic systems based on parallelism and concurrencyrequire new ideas for integrating the intelligent “devices”, collaborativerobots (COBOTS), into IoT applications. Dynamic maintainability, selfhealing,self-repair of resources, changing resource state, (re-) configurationand context based IoT systems for service implementation and integrationwith IoT network service composition are of paramount importance whennew “cognitive devices” are becoming active participants in IoT applications.This chapter aims to be an overview of the IoRT concept, technologies,architectures and applications and to provide a comprehensive coverage offuture challenges, developments and applications
Unified decoupling scheme for exchange and anisotropy contributions and temperature-dependent spectral properties of anisotropic spin systems
We compute the temperature-dependent spin-wave spectrum and the magnetization
for a spin system using the unified decoupling procedure for the high-order
Green's functions for the exchange coupling and anisotropy, both in the
classical and quantum case. Our approach allows us to establish a clear
crossover between quantum-mechanical and classical methods by developing the
classical analog of the quantum Green's function technique. The results are
compared with the classical spectral density method and numerical modeling
based on the stochastic Landau-Lifshitz equation and the Monte Carlo technique.
As far as the critical temperature is concerned, there is a full agreement
between the classical Green's functions technique and the classical spectral
density method. However, the former method turns out to be more straightforward
and more convenient than the latter because it avoids any \emph{a priori}
assumptions about the system's spectral density. The temperature-dependent
exchange stiffness as a function of magnetization is investigated within
different approaches
High energy protons from PKS 1333-33
In this letter we give an account of the possible acceleration of protons in
the outer radio lobes of the active galaxy PKS 1333-33. We also make estimates
of the arrival energy spectrum.Comment: 3 pages revtex, two figures, to appear in Mod. Phys. Lett.
Two-years surveillance of fungal contamination in three hospital departments in Campania Region
A two-years (2003-2005) fungal environmental surveillance was carried out in three departments of a hospital in Campania region (Surgery, Intensive Care Unit, Obstetrics and Gynaecology). Four operating theatres rooms and their relative areas of service and support, 4 patient rooms of intensive care unit,
1 delivery room, 1 labour room and 1 nursery of Obstetrics and Gynaecology were checked. Atotal of 12,120 surfaces and 2,904 air samples were collected in 24 monthly determinations. A seasonal variation in the fungal development was observed, in particular the lowest level of air and surface fungi contamination
was found in winter and autumn whereas it was higher in spring and summer. In this study 30 fungal species were identified and, among these, the most frequent specie isolated was the Aspergillus spp. The results show an air contamination, expressed in percentage of positive determinations for Aspergillus spp, and the other fungi in the following percentages: Obstetrics and Gynaecology (25% and 33,3%); Intensive Care Unit (17% and 25%); Surgery (12.5% and 21%). For surfaces contamination it was found: Obstetrics and Gynaecology (67% and 75%); Intensive Care Unit (63% and 71%); Surgery
(58.3% and 67%). This study shows that in the departments observed environmental fungi contamination is always present and therefore it would be necessary to apply environmental surveillance procedure and monitor the effectiveness
Investigating the early pottery Neolithic of northern Syria:New evidence from Tell Sabi Abyad
Comparison of Control Modes of a Hand-Held Robot for Laparoscopic Surgery
Teleoperated robots for minimally invasive surgery make surgeons loose direct contact with the patient. We are developing a handheld, dexterous surgical robot that can be controlled with one hand only, while standing at the operating table. The instrument is composed of a master part (the handle) and a slave part (the tip). This work compares the performance of different control modes, i.e. different ways to map the degrees of freedom of the handle to those of the tip. We ask users to drive the tip along complex trajectories in a virtual environment, using
the real master to drive a simulated slave, and assess their performance. Results show that, concerning time, users with no training in laparoscopy prefer a direct mapping of position and orientation, like in free hand motion. However, users trained in laparoscopy perform equally fast with our hand-held robot and, concerning precision, make a smaller number of errors
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