11. Binary division fuzzy C-means clustering and particle swarm optimization based efficient intrusion detection for e-governance systemsSunil K. Muttoo, Saibal K. Pal, 2016, izvirni znanstveni članek Opis: With the rapid rise of technology, many unusual and unwanted patterns have been observed in the communication network andrespective systems. This may be attributed to the increase of external threats that cause many security concerns. Such anomalies and unusual behavior lead to a strong need of studying and designing the Intrusion Detection Systems and Clustering. Currently,a variety of clustering methods and their combinations are used to develop an efficient intrusion detection system, but some metrics like low detection rate and high false alarm rate make these models unsatisfactory. The problem of local minima for clustering technique makes their search ability less efficient. An evolutionary technique called particle swarm optimization algorithm, that is based on swarm intelligence, shows a high global maxima search capability. In this paper, these two techniques have been combined to present a novel approach called fuzzy based particle swarm algorithm for the implementation of intrusion detection system. The experiment was conducted on a new data set called Kyoto data set with more number of anomalies. The obtained results were compared with two traditional clustering techniques based on K-Means and Fuzzy C-Means. It was observed that the proposed algorithm outperformed the other two traditional methods on the basis of the Detection Rate and False Alarm rate. In past some researchers have presented the combination of Fuzzy Based Particle Swarm Optimization algorithm to improve the intrusion detection rate,but this rate has been further improved because the algorithm performance depends on the termination condition and the fitness function value which are new in the proposed algorithm. Moreover, cluster numbers have been considered differently in the past, whereas the proposed algorithm works only on binary clustering.
Ključne besede: intrusion detection, fuzzy C-means clustering, particle swarm optimization, detection rate, e-governance
Objavljeno v RUNG: 01.04.2021; Ogledov: 1905; Prenosov: 0
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12. The impact of cloudiness and cloud type on the atmospheric heating rate of black and brown carbon in the Po ValleyLuca Ferrero, Asta Gregorič, Griša Močnik, Martin Rigler, Sergio Cogliati, Francesca Barnaba, Luca Di Liberto, Gian Paolo Gobbi, Niccolò Losi, Ezio Bolzacchini, 2021, izvirni znanstveni članek Opis: We experimentally quantified the impact of cloud fraction and cloud type on the heating rate (HR) of black and brown carbon (HRBC and HRBrC). In particular, we examined in more detail the cloud effect on the HR detected in a previous study (Ferrero et al., 2018). High-time-resolution measurements of the aerosol absorption coefficient at multiple wavelengths were coupled with spectral measurements of the direct, diffuse and surface reflected irradiance and with lidar–ceilometer data during a field campaign in Milan, Po Valley (Italy). The experimental set-up allowed for a direct determination of the total HR (and its speciation: HRBC and HRBrC) in all-sky conditions (from clear-sky conditions to cloudy). The highest total HR values were found in the middle of winter (1.43 ± 0.05 K d−1), and the lowest were in spring (0.54 ± 0.02 K d−1). Overall, the HRBrC accounted for 13.7 ± 0.2 % of the total HR, with the BrC being characterized by an absorption Ångström exponent (AAE) of 3.49 ± 0.01. To investigate the role of clouds, sky conditions were classified in terms of cloudiness (fraction of the sky covered by clouds: oktas) and cloud type (stratus, St; cumulus, Cu; stratocumulus, Sc; altostratus, As; altocumulus, Ac; cirrus, Ci; and cirrocumulus–cirrostratus, Cc–Cs). During the campaign, clear-sky conditions were present 23 % of the time, with the remaining time (77 %) being characterized by cloudy conditions. The average cloudiness was 3.58 ± 0.04 oktas (highest in February at 4.56 ± 0.07 oktas and lowest in November at 2.91 ± 0.06 oktas). St clouds were mostly responsible for overcast conditions (7–8 oktas, frequency of 87 % and 96 %); Sc clouds dominated the intermediate cloudiness conditions (5–6 oktas, frequency of 47 % and 66 %); and the transition from Cc–Cs to Sc determined moderate cloudiness (3–4 oktas); finally, low cloudiness (1–2 oktas) was mostly dominated by Ci and Cu (frequency of 59 % and 40 %, respectively).
HR measurements showed a constant decrease with increasing cloudiness of the atmosphere, enabling us to quantify for the first time the bias (in %) of the aerosol HR introduced by the simplified assumption of clear-sky conditions in radiative-transfer model calculations. Our results showed that the HR of light-absorbing aerosol was ∼ 20 %–30 % lower in low cloudiness (1–2 oktas) and up to 80 % lower in completely overcast conditions (i.e. 7–8 oktas) compared to clear-sky ones. This means that, in the simplified assumption of clear-sky conditions, the HR of light-absorbing aerosol can be largely overestimated (by 50 % in low cloudiness, 1–2 oktas, and up to 500 % in completely overcast conditions, 7–8 oktas).
The impact of different cloud types on the HR was also investigated. Cirrus clouds were found to have a modest impact, decreasing the HRBC and HRBrC by −5 % at most. Cumulus clouds decreased the HRBC and HRBrC by −31 ± 12 % and −26 ± 7 %, respectively; cirrocumulus–cirrostratus clouds decreased the HRBC and HRBrC by −60 ± 8 % and −54 ± 4 %, which was comparable to the impact of altocumulus (−60 ± 6 % and −46 ± 4 %). A higher impact on the HRBC and HRBrC suppression was found for stratocumulus (−63 ± 6 % and −58 ± 4 %, respectively) and altostratus (−78 ± 5 % and −73 ± 4 %, respectively). The highest impact was associated with stratus, suppressing the HRBC and HRBrC by −85 ± 5 % and −83 ± 3 %, respectively. The presence of clouds caused a decrease of both the HRBC and HRBrC (normalized to the absorption coefficient of the respective species) of −11.8 ± 1.2 % and −12.6 ± 1.4 % per okta. This study highlights the need to take into account the role of both cloudiness and different cloud types when estimating the HR caused by both BC and BrC and in turn decrease the uncertainties associated with the quantification of their impact on the climate.
Ključne besede: black carbon, brown carbon, cloud, atmospheric heating rate, climate change
Objavljeno v RUNG: 29.03.2021; Ogledov: 2367; Prenosov: 0
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13. On the usage of classical nucleation theory in quantification of the impact of bacterial INP on weather and climateMaher Sahyoun, Heike Wex, Ulrich Karlson Gosewinkel, Tina Šantl Temkiv, Niels Woetman Nielsen, Kai Finster, Jens H. Sørensen, Frank Stratmann, Ulrik S. Korsholm, 2016, izvirni znanstveni članek Ključne besede: Ice nucleation, Bacterial INP, Ice nucleation active proteins, Classical nucleation theory, Ice nucleation rate
Objavljeno v RUNG: 04.01.2021; Ogledov: 2693; Prenosov: 0
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14. A feasibility study of the use of reactive tracers to determine outdoor daytime OH radical concentrations within the urban environmentIain R. White, Damien Martin, K Fredrik Petersson, Stephen J Henshaw, Graham Nickless, Guy C Lloyd-Jones, Kevin C Clemitshaw, Dudley E Shallcross, 2014, izvirni znanstveni članek Opis: Using a specifically designed chemical tracer to indirectly measure local atmospheric hydroxyl radical (OH) concentrations is a very appealing concept. Such a tracer will provide information on the amount of OH a tracer encounters, as it moves through the urban environment and provide a stringent test of models. However, to date an outdoor experiment such as this has not been conducted. This article discusses the reasons why this is so and examines the feasibility of using tracers to measure integrated urban OH levels over short (≤1km) distances.
Ključne besede: reactive tracers, OH radicals, NO3 radicals, oxidising rate, dispersion, urban
Objavljeno v RUNG: 18.07.2019; Ogledov: 3060; Prenosov: 0
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15. Experimental determination of black and brown carbon heating rate from mid-latitudes to the Arctic ocean, and related energy gradientLuca Ferrero, Luca Cataldi, Griša Močnik, Asta Gregorič, Piotr Markuszewski, Przemek Makuch, Paulina Pakszys, Tomek Petelski, E. Bolzacchini, Tymon Zielinski, 2019, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: black carbon, heating rate, Arctic
Objavljeno v RUNG: 17.07.2019; Ogledov: 3531; Prenosov: 0
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17. Influence of clouds on black carbon direct radiative effect and heating rate over MilanAsta Gregorič, Luca Ferrero, Griša Močnik, S. Cogliati, F. Barnaba, L. Di Liberto, G. P. Gobbi, E. Bolzacchini, 2017, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: black carbon, direct radiative effect, heating rate, clouds
Objavljeno v RUNG: 10.10.2017; Ogledov: 4555; Prenosov: 251
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18. Heart rate variability and nonlinear dynamic analysis in patients with stress-induced cardiomyopathyGoran Krstačić, Gianfranco Parati, Dragan Gamberger, Paolo Castiglioni, Antonija Krstačić, Robert Steiner, 2012, izvirni znanstveni članek Opis: Complexity-based analyses may quantify abnormalities in heart rate variability (HRV). The aim of this study was to investigate the clinical and prognostic significances of dynamic HRV changes in patients with stress-induced cardiomyopathy Takotsubo syndrome (TS) by means of linear and nonlinear analysis. Patients with TS were included in study after complete noninvasive and invasive cardiovascular diagnostic evaluation and compared to an age and gender matched control group of healthy subjects. Series of R–R interval and of ST–T interval values were obtained from 24-h ECG recordings after digital sampling. HRV analysis was performed by ‘range rescaled analysis’ to determine the Hurst exponent, by detrended fluctuation analysis to quantify fractal longrange correlation properties, and by approximate entropy to assess time-series predictability. Short- and long-term fractal-scaling exponents were significantly higher in patients with TS in acute phases, opposite to lower approximate entropy and Hurst exponent, but all variables normalized in a few weeks. Dynamic HRV analysis allows assessing changes in complexity features of HRV in TS patients during the acute stage, and to monitor recovery after treatment, thus complementing traditional ECG and clinically analysis.
Ključne besede: Heart rate variability, Nonlinear dynamics, Chaos theory, Stress-induced cardiomyopathy, Takotsubo syndrome
Objavljeno v RUNG: 13.07.2017; Ogledov: 5069; Prenosov: 0
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