In this work we present the architectural and performance studies concerning a prototype of a distributed Tier2 infrastructure for HEP, instantiated between the two Italian sites of INFN-Romal and INFN-Napoli. The net...
In this work we present the architectural and performance studies concerning a prototype of a distributed Tier2 infrastructure for HEP, instantiated between the two Italian sites of INFN-Romal and INFN-Napoli. The network infrastructure is based on a Layer-2 geographical link, provided by the Italian NREN (GARR), directly connecting the two remote LANs of the named sites. By exploiting the possibilities offered by the new distributed file systems, a shared storage area with synchronous copy has been set up. The computing infrastructure, based on an OpenStack facility, is using a set of distributed Hypervisors installed in both sites. The main parameter to be taken into account when managing two remote sites with a single framework is the effect of the latency, due to the distance and the end-to-end service overhead. In order to understand the capabilities and limits of our setup, the impact of latency has been investigated by means of a set of stress tests, including data I/O throughput, metadata access performance evaluation and network occupancy, during the life cycle of a virtual Machine. A set of resilience tests has also been performed, in order to verify the stability of the system on the event of hardware or software faults. The results of this work show that the reliability and robustness of the chosen architecture are effective enough to build a production system and to provide common services. This prototype can also be extended to multiple sites with small changes of the network topology, thus creating a National Network of Cloud-based distributed services, in HA over WAN.
A high-performancecomputing resource allows us to conduct numerical simulations with a horizontal grid spacing that is sufficiently high to resolve cloud systems. The cutting-edge computational capability, which was ...
A high-performancecomputing resource allows us to conduct numerical simulations with a horizontal grid spacing that is sufficiently high to resolve cloud systems. The cutting-edge computational capability, which was provided by the K computer at RIKEN in Japan, enabled the authors to perform long-term, global simulations of air pollutions and clouds with unprecedentedly high horizontal resolutions. In this study, a next generation model capable of simulating global air pollutions with O(10 km) grid spacing by coupling an atmospheric chemistry model to the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) was performed. Using the newly developed model, month-long simulations for July were conducted with 14 km grid spacing on the K computer. Regarding the global distributions of aerosol optical thickness (AOT), it was found that the correlation coefficient (CC) between the simulation and AERONET measurements was approximately 0.7, and the normalized mean bias was -10%. The simulated AOT was also compared with satellite-retrieved values; the CC was approximately 0.6. The radiative effects due to each chemical species (dust, sea salt, organics, and sulfate) were also calculated and compared with multiple measurements. As a result, the simulated fluxes of upward shortwave radiation at the top of atmosphere and the surface compared well with the observed values, whereas those of downward shortwave radiation at the surface were underestimated, even if all aerosol components were considered. However, the aerosol radiative effects on the downward shortwave flux at the surface were found to be as high as 10 W/m2 in a global scale; thus, simulated aerosol distributions can strongly affect the simulated air temperature and dynamic circulation.
In this work, we compare the supermassive black hole (SMBH) and host galaxy properties of X-ray obscured and unobscured AGN. For that purpose, we used ∼35 000 X-ray detected AGN in the 4XMM-DR11 catalogue for which t...
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In this work, we compare the supermassive black hole (SMBH) and host galaxy properties of X-ray obscured and unobscured AGN. For that purpose, we used ∼35 000 X-ray detected AGN in the 4XMM-DR11 catalogue for which there are available measurements for their X-ray spectral parameters, such as the hydrogen column density, NH, and photon index, Γ, from the XMM2Athena Horizon 2020 European project. We constructed the spectral energy distributions (SEDs) of the sources, and we calculated the host galaxy properties via SED fitting analysis, utilising the CIGALE code. We applied strict photometric requirements and quality selection criteria to include only sources with robust X-ray and SED fitting measurements. Our sample consists of 1443 AGN. In the first part of our analysis, we used different NH thresholds (1023 cm−2 or 1022 cm−2) while also taking into account the uncertainties associated with the NH measurements in order to classify these sources as obscured and unobscured (or mildly obscured). We find that obscured AGN tend to live in more massive systems (by ∼0.1 dex) that have a lower star-formation rate, SFR, (by ∼0.25 dex) compared to their unobscured counterparts. However, only the difference in stellar mass, M∗, appears statistically significant (>2σ). The results do not depend on the NH threshold used to classify AGN. The differences in M∗ and SFR are not statistically significant for luminous AGN (log (LX,2−10 Kev/erg s−1) > 44). Our findings also show that unobscured AGN have, on average, higher specific black hole accretion rates, λsBHAR, compared to their obscured counterparts, a parameter which is often used as a proxy of the Eddington ratio. In the second part of our analysis, we cross-matched the 1443 X-ray AGN with the SDSS DR16 quasar catalogue of Wu and Shen to obtain information on the SMBH properties of our sources. This resulted in 271 type 1 AGN at z H (>1022 cm−2) tend to have higher black hole masses, MBH, compared to AGN with lower NH values a
This paper evaluates the capacitive antenna performance (sensitivity and frequency shifting) as a lightning sensor in different antenna design structures. Two experiments were carried out, Experiment A - using two dif...
This paper evaluates the capacitive antenna performance (sensitivity and frequency shifting) as a lightning sensor in different antenna design structures. Two experiments were carried out, Experiment A - using two different structure antennas, an A3 size capacitive antenna and a quarter A4- sized capacitive antenna, capturing the electric field (E-field) generated by the small spark at a distance of 1 meter away from both antennas. The results were taken in a ratio form of the 1st pulse amplitude captured by quarter A4 size antenna verses 1st pulse amplitude of the waveform captured by A3 antenna for each corresponding spark. Same set up and measurement were taken during the Experiment B except for the quarter A4 size antenna was now being slotted with 6 copper plates were slotted within the gap between the top plate and bottom plate. The result from Experiment A showed an average ratio at 0.1957 with a range of 0.0333 to 0.3085 while the results of Experiment B showed the average value laid at 0.2606 within the range of 0.1581 to 0.4510. The comparison results of Experiment A with Experiment B gave an increment of the sensitivity of the quarter A4 antenna from no stack to fully stacked antenna. However, there was also a significant frequency shifting of the quarter A4 antenna with the change of antenna structure (15% for quarter A4 capacitive antenna without stack; 20% for quarter A4 stacked capacitive antenna).
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