4,376 research outputs found

    Towards engineering ontologies for cognitive profiling of agents on the semantic web

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    Research shows that most agent-based collaborations suffer from lack of flexibility. This is due to the fact that most agent-based applications assume pre-defined knowledge of agents’ capabilities and/or neglect basic cognitive and interactional requirements in multi-agent collaboration. The highlight of this paper is that it brings cognitive models (inspired from cognitive sciences and HCI) proposing architectural and knowledge-based requirements for agents to structure ontological models for cognitive profiling in order to increase cognitive awareness between themselves, which in turn promotes flexibility, reusability and predictability of agent behavior; thus contributing towards minimizing cognitive overload incurred on humans. The semantic web is used as an action mediating space, where shared knowledge base in the form of ontological models provides affordances for improving cognitive awareness

    A Multi-Channel Low-Power System-on-Chip for in vivo NeuralSpike Recording

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    This paper reports a multi-channel neural spike recording system-on-chip (SoC) with digital data compression and wireless telemetry. The circuit consists of a 64-channel low-power low-noise analog front-end, a single 8-bit analog-todigital converter (ADC), followed by digital signal compression and transmission units. The 400-MHz transmitter employs a Manchester-Coded Frequency Shift Keying (MC-FSK) modulator with low modulation index. In this way a 1.25-Mbit/s data rate is delivered within a band of about 3 MHz. Compression of the raw data is implemented by detecting the action potentials (APs) and storing 20 samples for each spike waveform. The choice greatly improves data quality and allows single neuron identification. A larger than 10-m transmission range is reached with an overall power consumption of 17.2 mW. This figure translates into a power budget of 269 ÎĽW per channel, which is in line with the results in literature but allowing a larger transmission distance and more efficient wireless link bandwidth occupation. The implemented IC was mounted on a small and light printed circuit board to be used during neuroscience experiments with freely-behaving rats. Powered by 2 AAA batteries the system can work continuously for more than 100 hours allowing long-lasting neural spike recordings

    Video-assisted two-stage basilic vein transposition for creation of brachio-basilic arteriovenous fistulae

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    We report our experience in a mixed minimally-in- vasive technique for the two-stage transposition of basilic vein on a small series of eight patients. The operative tech- nique consisted of a modified endoscopic (1) approach for the two-stage transposition (2). The intervention was performed under Brachial Plexus Block (3)

    Automated detection of lung nodules in low-dose computed tomography

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    A computer-aided detection (CAD) system for the identification of pulmonary nodules in low-dose multi-detector computed-tomography (CT) images has been developed in the framework of the MAGIC-5 Italian project. One of the main goals of this project is to build a distributed database of lung CT scans in order to enable automated image analysis through a data and cpu GRID infrastructure. The basic modules of our lung-CAD system, consisting in a 3D dot-enhancement filter for nodule detection and a neural classifier for false-positive finding reduction, are described. The system was designed and tested for both internal and sub-pleural nodules. The database used in this study consists of 17 low-dose CT scans reconstructed with thin slice thickness (~300 slices/scan). The preliminary results are shown in terms of the FROC analysis reporting a good sensitivity (85% range) for both internal and sub-pleural nodules at an acceptable level of false positive findings (1-9 FP/scan); the sensitivity value remains very high (75% range) even at 1-6 FP/scanComment: 4 pages, 2 figures: Proceedings of the Computer Assisted Radiology and Surgery, 21th International Congress and Exhibition, Berlin, Volume 2, Supplement 1, June 2007, pp 357-35

    Un generatore di impulso ad alta tensione per l'eccitazione di trasduttori piezoelettrici: un metodo per studiare la propagazione delle onde elastiche su campioni di rocce

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    Il dispositivo qui presentato è stato realizzato per lo studio della propagazione di onde elastiche in campioni di roccia [Wood A. W. Et al. 1955]. Mediante tale tecnica si riescono a determinare alcune caratteristiche fisiche delle rocce. Si tratta di un generatore di impulsi ad alta tensione, necessario per l’eccitazione di trasduttori piezoelettrici. La durata dell’impulso generato è di 1 s, l’ampiezza dell’ordine del kVolt. Il metodo utilizzato per effettuare la misura consiste nell’eccitare il trasduttore in trasmissione con un singolo impulso e quindi misurarne il tempo di volo con il trasduttore di ricezione. Il lavoro, oltre alla descrizione dello strumento, mostra alcuni esperimenti condotti su campioni di alluminio e diversi tipi di roccia. Tali esperimenti si sono resi necessari sia per il collaudo dello strumento che per la messa a punto del metodo

    Post-transcriptional regulatory patterns revealed by protein-RNA interactions

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    The coordination of the synthesis of functionally-related proteins can be achieved at the post-transcriptional level by the action of common regulatory molecules, such as RNA–binding proteins (RBPs). Despite advances in the genome-wide identification of RBPs and their binding transcripts, the protein–RNA interaction space is still largely unexplored, thus hindering a broader understanding of the extent of the post-transcriptional regulation of related coding RNAs. Here, we propose a computational approach that combines protein–mRNA interaction networks and statistical analyses to provide an inferred regulatory landscape for more than 800 human RBPs and identify the cellular processes that can be regulated at the post-transcriptional level. We show that 10% of the tested sets of functionally-related mRNAs can be post-transcriptionally regulated. Moreover, we propose a classification of (i) the RBPs and (ii) the functionally-related mRNAs, based on their distinct behaviors in the functional landscape, hinting towards mechanistic regulatory hypotheses. In addition, we demonstrate the usefulness of the inferred functional landscape to investigate the cellular role of both well-characterized and novel RBPs in the context of human diseases

    Nitrogen Experiments on a Supersonic Linear Cascade For ORC Applications

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    A novel experiment has been conceived at Politecnico di Milano for the study of the flow within and downstream of supersonic cascades of Organic Rankine Cycle (ORC) turbines. This paper documents the first phase of the research, focused on the preliminary tests and studies performed by operating the facility with nitrogen as working fluid, to demonstrate the technical relevance of the experiment and the validity of the measurement system in a simplified thermodynamic condition. The set of measured data includes, beside the inlet total thermodynamic state, eight static pressure values obtained via taps manufactured on the test section rear end-wall, both within the bladed and semi-bladed region of the cascade, as well as a total pressure probe to retrieve the cascade performance. A double-passage Schlieren equipment was also employed to visualize the density gradients. Experiments show an outstanding repeatability, indicate a quasi -steady cascade operation during the blow-down process for all the pressure signal considered, and demonstrate a remarkable periodicity among two consecutive channels also in off-design conditions. Experimental data were also compared with CFD simulations, resulting in an excellent agreement for the pressure data acquired both within and downstream of the cascade

    Time Dynamics of the Down-Coupling Phenomenon in 3-D NAND Strings

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    We present a detailed analysis of the time dynamics of the down-coupling phenomenon (DCP) in 3-D NAND Flash memory strings. The transient time dynamics of the channel potential following the wordline (WL) bias transition fromthe pass voltage to zero is studied via numerical simulation, highlighting the existence of three temporal regimes controlledby different physical processes: electron emission from traps, hole injection from the string edges followed by capture, and propagation along the string. The impact of these processes is separately studied, followed by an analysis of the dependence of the DCP recovery time on architectural parameters. Results highlight the relevant physics and can be used as a design guideline for NAND strings with reduced sensitivity to the DCP
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