53 research outputs found
GDOM: Granulometry for the Detection of Obfuscated Malware
We describe the results of a master\u27s thesis in malware detection and discuss the connection to the learning goals of the project. As part of the thesis, we studied obfuscation of malware, conversion of files into images, image processing, and machine learning, a process of benefit to both the student and faculty.
Malware detection becomes significantly more difficult when the malicious specimen is obfuscated or transformed in an attempt to avoid detection. However, computer files have been shown to exhibit evidence of structure when converted into images, so with image processing filters such as granulometry, it is possible to generate a set of features which will help characterize malicious and non-malicious files. If the structures of file-derived images are resistant to obfuscation, these images may be of valuable use in providing malware signatures. We explore image generated file features and their effectiveness to identify malware when used with various machine learning classifiers
PM10 source apportionment based on PMF and chemical tracers during different cruises in Western Mediterranean
In the Western Mediterranean Basin, frequently exposed to high levels of air pollutants, an important source of pollution which influence the emission, is the intensive ship traffic. The Joint Research Centre of the European Commission (JRC, EC) has started a long-term monitoring program along different years over the Mediterranean Sea based on observations from a cruise ship following a regular route in the Western Mediterranean, in collaboration with the Department of Physics of University of Genoa. In this framework, an intensive PM10 sampling campaign was organized in the summer of 2011, in order to fill in the gap of data recovered (in term of PM speciation) during the previous campaigns (Schembari et al., 2014) and to get a better and complete description of PM sources. During this campaign the route of the ship was Civitavecchia-Savona-Barcelona-Palma de Mallorca- Malta (Valletta)-Palermo-Civitavecchia (see Figure 1). The PM samples were collected on Quartz and Teflon filters (47mm diameter, flow rate 2.3 m3/h) using in parallel two Sven Leckel Ingenieurburo sequential samplers, placed on the top of the cabin where the monitoring and meteorological station was located. Samples were analyzed with different techniques: Energy Dispersive X-Ray Fluorescence at the Department of Physics of Genoa (Ariola et al, 2006); Ion Chromatography (Chow and Watson, 1999) at Department of Chemistry of University of Milan; Thermo-optical analysis (Birch and Cary, 1996) at the JRC laboratory. Ion Beam Analysis measurements of the Teflon filters sampled during the week of September 2011, using simultaneously PIXE, EBS and PESA techniques (Chiari, 2005), were performed at the 3 MV Tandetron accelerator of the LABEC laboratory of INFN in Florence. The data were used to identify and characterize the main PM10 sources along the ship route, with a focus on ship emissions, through apportionment Positive Matrix Factorization receptor modelling, PMF (Paatero et al, 1994). Particular attention was given to the evidence of emissions from heavy fuel oil combustion by ships, known to be an important source of secondary sulphate aerosol. Five sources of aerosol were resolved by the PMF analysis with a new database. The analysis allows distinguishing between secondary and primary particle mass resulting from ship emissions: V and Ni were found to be suitable tracers of heavy fuel oil combustion source during the campaign. The source having the largest impact on PM10 was identified as Sulphate source by PMF. The correlations between Sulphate and V and Ni showed the influence of ship emissions on sulphate in marine air masses
Impact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter in Venice air
Harbours are important hubs for economic growth in both tourism and commercial activities. They are also an environmental burden being a source of atmospheric pollution often localized near cities and industrial complexes. The aim of this study is to quantify the relative contribution of maritime traffic and harbour activities to atmospheric pollutant concentration in the Venice lagoon. The impact of ship traffic was quantified on various pollutants that are not directly included in the current European legislation for shipping emission reduction: (i) gaseous and particulate PAHs; (ii) metals in PM10; and (iii) PM10 and PM2.5. All contributions were correlated with the tonnage of ships during the sampling periods and results were used to evaluate the impact of the European Directive 2005/33/EC on air quality in Venice comparing measurements taken before and after the application of the Directive (year 2010). The outcomes suggest that legislation on ship traffic, which focused on the issue of the emissions of sulphur oxides, could be an efficient method also to reduce the impact of shipping on primary particulate matter concentration; on the other hand, we did not observe a significant reduction in the contribution of ship traffic and harbour activities to particulate PAHs and metals
Fault current increase due to the progressive undergrounding of HV subtransmission network
The undergrounding of HV subtransmission networks in urban/suburban areas is bound to increase fault currents, especially for ground faults if system neutral is solidly grounded. A parametric fault analysis based on symmetrical components is applied to a sample HV system with three lines and two EHV points of supply, based on a simple meshed Italian subtransmission network. Results are then validated by detailed three-phase ATP-EMTP simulations. Values yielded by the parametric study confirm the expected increase of all fault levels, reaching up to 36% and 69% for three-phase and 1-phase-to-ground faults, and even 104% for the ground current of phase-to-phase-to-ground faults. All calculated values are however tolerable, with fault currents well within the operating envelope of devices and components; cross-bonded sheaths also significantly relieve substation grounding mats. Some consequences of undergrounding such as reduction of earth-fault factor may be actually beneficial
best PhD poster Award, EEEIC15
The undergrounding of HV subtransmission networks in urban/suburban areas is bound to increase fault currents, especially for ground faults if system neutral is solidly grounded. A parametric fault analysis based on symmetrical components is applied to a sample HV system with three lines and two EHV points of supply, based on a simple meshed Italian subtransmission network. Results are then validated by detailed three-phase ATP-EMTP simulations. Values yielded by the parametric study confirm the expected increase of all fault levels, reaching up to 36% and 69% for three-phase and 1-phase-to-ground faults, and even 104% for the ground current of phase-to-phase-to-ground faults. All calculated values are however tolerable, with fault currents well within the operating envelope of devices and components; cross-bonded sheaths also significantly relieve substation grounding mats. Some consequences of undergrounding such as reduction of earth-fault factor may be actually beneficial
Optimal power flow application to EHVAC interconnections for GW-sized Offshore Wind Farms
Operation of long EHVAC cable interconnectors requires controlling voltage/reactive power profiles. With reference to a hypothetical 200 km long 400 kV-50 Hz cable system, connecting to the grid three large OWFs with 2 GW total capacity, the paper compares results yielded by a dedicated algorithm with those of a standard OPF software. A parametric study of the interconnector was carried out, considering different dispatch scenarios and boundary conditions (network connection point voltages). Several cases were ran for an enlarged, meshed test system including the interconnector. Results show that solutions yielded by OPF and by the authors' algorithm are very close, confirming the effectiveness of the latter but also its possible replacement by a standard OPF when dealing with non-radial cable system topologies
A comparison of daily total locomotor activity between the lactation and the dry period in dairy cattle
The objective of this study was to investigate the influence of farming management on the total locomo- tor activity (TLA) behaviour in dairy cattle. We recorded 24 h/day TLA in five not pregnant Holstein Frie- sian cows during parts of the lactation and dry periods, by means of an activity monitoring system (Actiwatch mini
2) for seven days in each period. During mild lactation (period 1) animals were milked and fed twice a day. During the dry (period 2) they were kept to graze all day. In both periods hay and water were available ad libitum. Differences between the photophase and the scotophase were evaluated with a Student t-test. One-way repeated measure ANOVA was used to determine a statistical significant effect of time. A trigonometric statistical model was used to describe the main rhythmic parameters: mean level, amplitude, acrophase and robustness of rhythm.
Our results showed a circadian rhythm of daily TLA in both periods, with different percentages of robustness, and acrophase in the middle of the photophase. The different patterns of activity in the two periods were attributed to the management practise during milking period. These results could be taken in consideration during farming management for the evaluation of such systems used in livestock, with respect to production and welfare
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Social cognition and short-term prediction of suicidal ideation in schizophrenia
•Negative social cognitive biases, ratings of more extremely untrustworthy faces, and increased accuracy in recognizing negative affect were associated with suicidal ideation in schizophrenia.•Negative social cognitive bias was associated with the presence of suicidal ideation at two weeks follow up assessment.•Negative biases in processing and interpreting social information may foster suicidal thinking in schizophrenia.
Despite recent research acknowledging social cognition as an important feature of interpersonal functioning in schizophrenia, little work has evaluated the role of social cognition in suicidal ideation and behavior in psychosis. In a short-term longitudinal study, we evaluated the association between concurrent and near term suicidal ideation with social cognition, including emotion recognition and related biases (ER-40; BLERT), attribution biases (AIHQ), and evaluations of trustworthiness (trustworthiness task) in a sample of 179 outpatients with schizophrenia or schizoaffective disorder. Adjusting for severity of positive and general mental health symptoms, greater reactivity to extreme stimuli (trustworthiness measure), BLERT negative affect accuracy, and AIHQ Blame Scores were associated with suicidal ideation at baseline. AIHQ Blame Scores also longitudinally predicted the presence of ideation 2 weeks later and were highest among participants with ideation across the two time points. The present findings provide support that biased interpretations, and, concurrently with ideation, reactivity and selective accuracy to negative stimuli, are associated with suicidal ideation in schizophrenia. Further understanding the role of social cognitive ability and biases on suicidal ideation could contribute to the understanding of social cognition as a treatment target in prevention of suicidal behavior in schizophrenia
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