1,856 research outputs found
Motor Database for the Optimal Selection of Motor-Reducer Unit by Continuous Approach
No full textThis dataset is linked with the article: "Optimal Selection of the Motor-Reducer Unit in Servo-Controlled Machinery: a Continuous Approach" by Meoni,F and Carricato, M. The dataset contains motors parameters, both from commercial catalogs and inferred by an electromechanical model, which are used to create a continuous catalog. The final goal of the research the optimal selection of the motor-reducer unit
Web-based Semantic Browsing of Video Collections using Multimedia Ontologies
No full textIn this technical demonstration we present a novel web-based tool that allows a user friendly semantic browsing of video collections, based on ontologies, concepts, concept relations and concept clouds. The system is developed as a Rich Internet Application (RIA) to achieve a fast responsiveness and ease of use that can not be obtained by other web application paradigms, and uses streaming to access and inspect the videos. Users can also use the tool to browse the content of social and media sharing sites like YouTube, Flickr and Twitter, accessing these external resources through the ontologies used in the system. The tool has won the second prize in the Adobe YouGC contest, in the RIA category
Dataset Popularity Prediction for Caching of CMS Big Data
No full textThe Compact Muon Solenoid (CMS) expe- riment at the European Organization for Nuclear Research (CERN) deploys its data collections, simula- tion and analysis activities on a distributed computing infrastructure involving more than 70 sites worldwide. The historical usage data recorded by this large infras- tructure is a rich source of information for system tun- ing and capacity planning. In this paper we investigate how to leverage machine learning on this huge amount of data in order to discover patterns and correlations useful to enhance the overall efficiency of the dis- tributed infrastructure in terms of CPU utilization and task completion time. In particular we propose a scal- able pipeline of components built on top of the Spark engine for large-scale data processing, whose goal is collecting from different sites the dataset access logs, organizing them into weekly snapshots, and training, on these snapshots, predictive models able to fore- cast which datasets will become popular over time. The high accuracy achieved indicates the ability of the learned model to correctly separate popular datasets from unpopular ones. Dataset popularity predictions are then exploited within a novel data caching policy, called PPC (Popularity Prediction Caching). We eval- uate the performance of PPC against popular caching policy baselines like LRU (Least Recently Used). The experiments conducted on large traces of real dataset accesses show that PPC outperforms LRU reducing the number of cache misses up to 20% in some sites
AN APPARATUS FOR SCINTIGRAPHIC ANALYSIS, PARTICULARLY A MAMMOGRAPH,WITH SUB-MILLIMETRIC SPATIAL RESOLUTION
No full textA scintigraphic mammograph with sub-millimetric spatial resolution adapted to detect gamma radiations with 30 KeV to 2 MeV energy, comprising a sensitive head section (10) with a box shaped shielding container (16) co-operating with a standard pressure member and receiving the following essential components combined together in the following succession: an apertured collimator (11), of a high atomic number material, adapted to collimate the gamma radiation emissions from the body organ being investigated; a scintillating crystal and fluorescent fiber structure adapted to convert the gamma radiations emitted from the concerned body organ into light radiations; a multi-anode or crossed wire photo-multiplier or position sensitive solid state detector, which receives the light radiations emitted from said scintillating crystals and fluorescent fibers and generates signals proportional to the received light radiations; a hardware assembly adapted to perform conversion and integration of all signals generated by said photo-multiplier assembly from an analog to a digital format as well as their amplification in order to subsequently couple them to an electronic processor which processes and displays then on a suitable monitor in the form of an image of the concerned body organ
Popularity-Based Caching of CMS Datasets
No full textThe distributed monitoring infrastructure of the Compact Muon Solenoid (CMS) experiment at the European Organization for Nuclear Research (CERN) records on a Hadoop infrastructures a broad variety of computing and storage logs. They represent a valuable source of information for system tuning and capacity planning. In this paper we analyze machine learning (ML) techniques on large amount of traces to discover patterns and correlations useful to classify the popularity of experiment-related datasets. We implement a scalable pipeline of Spark components which collect the dataset access logs from heterogeneous monitoring sources and group them into weekly snapshots organized by CMS sites. Predictive models are trained on these snapshots and forecast which dataset will become popular over time. Dataset popularity predictions are then used to experiment a novel strategy of data caching, called Popularity Prediction Caching (PPC). We compare the hit rates of PPC with those produced by well known caching policies. We demonstrate how the performance improvement is as high as 20% in some sites
Analysis of microsaccade direction during learning of an attentional task in the macaque monkey.
No full textSirio, Orione and Pan: an Integrated Web System for Ontology-based Video Search and Annotation
No full textIn this technical demonstration we show an integrated web system for video search and annotation based on ontologies. The system is composed by three components: the Orione ontology-based search engine, the Sirio\footnote{Sirio was the hound of Orione. It was a dog so swift that no prey could escape it.} search interface, and the Pan web-based video annotation tool. The system is currently being developed within the EU IM3I project. The goal of the system is to provide an integrated environment for video annotation and retrieval of videos, for both technical and non-technical users. In fact, the search engine has different interfaces that permit different query modalities: free-text, natural language, graphical composition of concepts using Boolean and temporal relations and query by visual example. In addition, the ontology structure is exploited to encode semantic relations between concepts permitting, for example, to expand queries to synonyms and concept specializations. The annotation tool can be used to create ground-truth annotations to train automatic annotations systems, or to complement the results of automatic annotation, e.g. adding geolocalized information
Analysis of microsaccades during extended practice of a visual discrimination task in the macaque monkey
No full textThe spatial location indicated by a visual cue can bias microsaccades directions towards or away from the cue. Aim of this work was to evaluate the microsaccades characteristics during the monkey's training, investigating the relationship between a shift of attention and practice. The monkey was trained to press a lever at a target onset, then an expanding optic flow stimulus appeared to the right of the target. After a variable time delay, a visual cue appeared within the optic flow stimulus and the monkey had to release the lever in a maximum reaction time (RT) of 700 ms. In the control task no visual cue appeared and the monkey had to attend a change in the target color. Data were recorded in 9 months. Results revealed that the RTs at the control task changed significantly across time. The microsaccades directions were significantly clustered toward the visual cue, suggesting that the animal developed an attentional bias toward the visual space where the cue appeared. The microsaccades amplitude differed significantly across time. The microsaccades peak velocity differed significantly both across time and within the time delays, indicating that the monkey made faster microsaccades when it expected the cue to appear. The microsaccades number was significantly higher in the control task with respect to discrimination. The lack of change in microsaccades rate, duration, number and direction across time indicates that the experience acquired during practicing the task did not influence microsaccades generation
Sensory Input Modulates Microsaccades during Heading Perception
No full textMicrosaccades are small eye movements produced during attempted fixation. During locomotion, the eyes scan the environment; the gaze is not always directed to the focus of expansion of the optic flow field. We sought to investigate whether the microsaccadic activity was modulated by eye position during the view of radial optic flow stimuli, and if the presence or lack of a proprioceptive input signal may influence the microsaccade characteristics during self-motion perception. We recorded the oculomotor activity when subjects were either standing or sitting in front of a screen during the view of optic flow stimuli that simulated specific heading directions with different gaze positions. We recorded five trials of each stimulus. Results showed that microsaccade duration, peak velocity, and rate were significantly modulated by optic flow stimuli and trial sequence. We found that the microsaccade rate increased in each condition from trial 1 to trial 5. Microsaccade peak velocity and duration were significantly different across trials. The analysis of the microsaccade directions showed that the different combinations of optic flow and eye position evoked non-uniform directions of microsaccades in standing condition with mean vectors in the upper-left quadrant of the visual field, uncorrelated with optic flow directions and eye positions. In sitting conditions, all stimuli evoked uniform directions of microsaccades. Present results indicate that the proprioceptive signals when the subjects stand up creates a different input that could alter the eye-movement characteristics during heading perceptions
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