329 research outputs found

    On the Viability of Quantitative Assessment Methods in Software Engineering and Software Services

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    IT help desk operations are expensive. Costs associated with IT operations present challenges to profit goals. Help desk managers need a way to plan staffing levels so that labor costs are minimized while problems are resolved efficiently. An incident prediction method is needed for planning staffing levels. The potential value of a solution to this problem is important to an IT service provider since software failures are inevitable and their timing is difficult to predict. In this research, a cost model for help desk operations is developed. The cost model relates predicted incidents to labor costs using real help desk data. Incidents are predicted using software reliability growth models. Cluster analysis is used to group products with similar help desk incident characteristics. Principal Components Analysis is used to determine one product per cluster for the prediction of incidents for all members of the cluster. Incident prediction accuracy is demonstrated using cluster representatives, and is done so successfully for all clusters with accuracy comparable to making predictions for each product in the portfolio. Linear regression is used with cost data for the resolution of incidents to relate incident predictions to help desk labor costs. Following a series of four pilot studies, the cost model is validated by successfully demonstrating cost prediction accuracy for one month prediction intervals over a 22 month period

    Localization of 102 exons to a 2.5 Mb region involved in Down syndrome

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    Exon amplification has been applied to a 2.5 Mb region of chromosome 21 that has been associated with some features of Down syndrome (DS). Identification of the majority of genes from this region will facilitate the correlation of the over-expression of particular genes with specific phenotypes of DS. Over 100 gene fragments have been isolated from this 2.5 Mb segment. The exons have been characterized by sequence analysis, comparison with public databases and expansion to cDNA clones. Localization of the exons to chromosome 21 has been determined by hybridization to genomic Southern blots and to YAC and cosmid clones representing the region. This has resulted in a higher resolution physical map with a marker approximately every 25 kb. This integrated physical and transcript map will be valuable for fine mapping of DNA from individuals with partial aneuploidy of chromosome 21 as well as for assessing and ultimately generating a complete gene map of this segment of the genom

    Severe acute respiratory syndrome coronavirus 2 detection by real time polymerase chain reaction using pooling strategy of nasal samples

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    COVID-19 is a life-threatening multisistemic infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Infection control relies on timely identification and isolation of infected people who can alberg the virus for up to 14 days, providing important opportunities for undetected transmission. This note describes the application of rRT-PCR test for simpler, faster and less invasive monitoring of SARS-CoV-2 infection using pooling strategy of samples. Seventeen positive patients were provided with sterile dry swabs and asked to self-collected 2 nasal specimens (#NS1 and #NS2). The #NS1 was individually placed in a single tube and the #NS2 was placed in another tube together with 19 NSs collected from 19 negative patients. Both tubes were then tested with conventional molecular rRT-PCR and the strength of pooling nasal testing was compared with the molecular test performed on the single NS of each positive patient. The pooling strategy detected SARS-CoV-2 RNA to a similar extent to the single test, even when Ct value is on average high (Ct 37-38), confirming that test sensibility is not substantially affected even if the pool contains only one low viral load positive sample. Furthermore, the pooling strategy have benefits for SARS-CoV-2 routinary monitoring of groups in regions with a low SARS-CoV-2 prevalenc

    Back analysis of the 2014 San Leo Landslide using combined terrestrial laser scanning and 3D distinct element modelling

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    This is the author accepted manuscript. The final version is available from Springer Verlag via http://dx.doi.org/10.1007/s00603-015-0763-5© 2015 Springer-Verlag Wien Landslides of the lateral spreading type, involving brittle geological units overlying ductile terrains, are a common occurrence in the sandstone and limestone plateaux of the northern Apennines of Italy. The edges of these plateaux are often the location of rapid landslide phenomena, such as rock slides, rock falls and topples. In this paper, we present a back analysis of a recent landslide (February 2014), involving the north-eastern sector of the San Leo rock slab (northern Apennines, Emilia-Romagna Region) which is a representative example of this type of phenomena. The aquifer hosted in the fractured slab, due to its relatively higher secondary permeability in comparison to the lower clayey units leads to the development of perennial and ephemeral springs at the contact between the two units. The related piping erosion phenomena, together with slope processes in the clay-shales have led to the progressive undermining of the slab, eventually predisposing large-scale landslides. Stability analyses were conducted coupling terrestrial laser scanning (TLS) and distinct element methods (DEMs). TLS point clouds were analysed to determine the pre- and post-failure geometry, the extension of the detachment area and the joint network characteristics. The block dimensions in the landslide deposit were mapped and used to infer the spacing of the discontinuities for insertion into the numerical model. Three-dimensional distinct element simulations were conducted, with and without undermining of the rock slab. The analyses allowed an assessment of the role of the undermining, together with the presence of an almost vertical joint set, striking sub-parallel to the cliff orientation, on the development of the slope instability processes. Based on the TLS and on the numerical simulation results, an interpretation of the landslide mechanism is proposed

    Testing General Relativity vs. Alternative Theories of Gravitation with the SaToR-G Experiment

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    A new experiment in the field of gravitation, SaToR-G, is presented. The experiment aims to compare the predictions of different theories of gravitation in the limit of weak-field and slow-motion. The ultimate goal of the experiment is to look for possible "new physics" beyond the current standard model of gravitation based on the predictions of General Relativity. A key role in the above perspective is the theoretical and experimental framework within which to confine our work. To this end, we will try to exploit as much as possible the framework suggested by Dicke over fifty years ago

    SEISMIC SWARM vs MAINSHOCK‐AFTERSHOCKS SEQUENCE: REFINED HYPOCENTERS LOCATIONS AT THE APENNINES‐CALABRIAN ARC BOUNDARY (SOUTHERN ITALY)

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    In the last years the Apennines-Calabrian arc boundary has been affected by intense seismicity concentrated in the Pollino mountain region. The Pollino is located at the northernmost edge of the Calabrian Arc, the last remnant of subduction along the Africa- Eurasian boundary. The area is subject to Northeast- Southwest extension, which results in a complex system of normal faults striking Northwest-Southeast, nearly parallel to the Apenninic mountain range. The Italian Seismic Network between 2010 and 2014 detected more than 5500 earthquakes in the area (Italian Seismological Instrumental and Parametric Data- Base; http:// iside .rm .ingv .it). In 2010 and 2011 the earthquake rate has been variable, with increasing and decreasing phases and maximum magnitudes below M=4. On May 28th 2012, a shallow event with local magnitude of 4.3 struck, about 5 kilometers east of the previous swarm. The seismic activity remained concentrated in the M=4.3 source region until early August. At that time seismicity jumped back westward to the previous area, with several earthquakes of magnitude larger than 3, culminating with a M=5.0 earthquake on 25 October 2012. The seismic rate remained high for some months, but aftershock magnitudes did not exceed magnitude 3.7. The seismic rate then suddenly decreased at the beginning of 2013 and stayed quite low for the rest of the year up to the beginning of 2014. During these years several temporary seismic stations were deployed in the area, improving the detecting threshold of the Italian Seismic Network and giving us the opportunity to refine the location of the earthquakes hypocenters. A combined dataset, including three-component seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D and 3D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the fault system responsible for the two strongest shocks. Swarm activity seems to occur on a diffuse crustal volume more than on fault planes. To yield a better understanding of the origin of the ongoing seismic activity in the Pollino area, using thousand of seismograms, we analyze vp and vp/vs models and anisotropic parameters in the crust. The main goal of this study is to increase the understanding of the physical mechanisms behind the seismic swarm and its influence on the seismic hazard of the Apennines- Calabrian arc boundary region.EAEE - ESCPublishedIstanbul - August 24-29 20142T. Tettonica attivaope

    The 2012 Emilia seismic sequence (Northern Italy): Imaging the thrust fault system by accurate aftershock location

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    Starting from late May 2012, the Emilia region (Northern Italy) was severely shaken by an intense seismic sequence, originated from a ML 5.9 earthquake on May 20th, at a hypocentral depth of 6.3 km, with thrusttype focal mechanism. In the following days, the seismic rate remained high, counting 50 ML ≄ 2.0 earthquakes a day, on average. Seismicity spreads along a 30 km east–west elongated area, in the Po river alluvial plain, in the nearby of the cities Ferrara and Modena. Nine days after the first shock, another destructive thrust-type earthquake (ML 5.8) hit the area to the west, causing further damage and fatalities. Aftershocks following this second destructive event extended along the same east-westerly trend for further 20 km to the west, thus illuminating an area of about 50 km in length, on thewhole. After the first shock struck, on May 20th, a dense network of temporary seismic stations, in addition to the permanent ones, was deployed in the meizoseismal area, leading to a sensible improvement of the earthquake monitoring capability there. A combined dataset, including threecomponent seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the thrust system responsible for the two strongest shocks

    The 2012 Emilia seismic sequence (Northern Italy): Imaging the thrust fault system by accurate aftershock location

    Get PDF
    Starting from late May 2012, the Emilia region (Northern Italy) was severely shaken by an intense seismic sequence, originated from a ML 5.9 earthquake on May 20th, at a hypocentral depth of 6.3 km, with thrusttype focal mechanism. In the following days, the seismic rate remained high, counting 50 ML ≄ 2.0 earthquakes a day, on average. Seismicity spreads along a 30 km east–west elongated area, in the Po river alluvial plain, in the nearby of the cities Ferrara and Modena. Nine days after the first shock, another destructive thrust-type earthquake (ML 5.8) hit the area to the west, causing further damage and fatalities. Aftershocks following this second destructive event extended along the same east-westerly trend for further 20 km to the west, thus illuminating an area of about 50 km in length, on thewhole. After the first shock struck, on May 20th, a dense network of temporary seismic stations, in addition to the permanent ones, was deployed in the meizoseismal area, leading to a sensible improvement of the earthquake monitoring capability there. A combined dataset, including threecomponent seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the thrust system responsible for the two strongest shocks.Published44-552T. Tettonica attivaJCR Journalope
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