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71.
Analysis Result of the High-Energy Cosmic-Ray Proton Spectrum from the ISS-CREAM Experiment
G. Choi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment successfully recorded the data for about 539 days from August 2017 to February 2019. In this talk, we report the measurement of the cosmic-ray proton energy spectrum from the ISS-CREAM experiment in the energy range of 2.5 TeV - 650 TeV. For the analysis, we used the silicon charge detector (SCD) placed at the top of the ISS-CREAM payload to identify the incoming cosmic-ray charge. The SCD is finely segmented to minimize charge misidentification due to backscatter effects. The four-layer SCD consists of 10,752 silicon pixels, each of which is 1.37×1.57×0.05 cm^3 in size. The calorimeter (CAL) consists of 20 layers of tungsten/scintillating fibers preceded by carbon targets. It provided cosmic-ray tracking, energy determination, and the high-energy trigger. The Top and Bottom Counting detectors (T/BCD) are above and below the CAL, respectively, and provided the low energy trigger. Each T/BCD is composed of an array of 20×20 photodiodes on plastic scintillators. The measured proton spectral index of 2.67±0.02 between 2.5 and 12.5 TeV is consistent with prior CREAM measurements. The spectrum softens above ∼10 TeV consistent with the bump-like structure as reported by CREAM-I+III, DAMPE, and NUCLEON, but ISS-CREAM extends measurements to higher energies than those prior measurement
Ključne besede: ISS-CREAM, silicon charge detector, calorimeter, direct detection, cosmic rays, protons, energy spectrum
Objavljeno v RUNG: 26.09.2023; Ogledov: 885; Prenosov: 6
.pdf Celotno besedilo (2,06 MB)
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72.
Results from the Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment
E.S. Seo, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment took high-energy cosmic ray data for 539 days after its successful installation on the ISS in August 2017. The ISS-CREAM instrument is configured with complementary particle detectors capable of measuring elemental spectra for Z = 1 - 26 nuclei in the energy range 10^12 – 10^15 eV; as well as electrons at multi-TeV energies. The goal is to understand cosmic ray origin, acceleration, and propagation by extending direct measurements of cosmic rays to energies that overlap the energy region of air showers measurements. The four layers of finely segmented Silicon Charge Detectors provide precise charge measurements. They have been designed to minimize hits of accompanying backscattered particles in the same segment as the incident cosmic ray particle to avoid charge misidentification. The sampling tungsten/scintillating-fiber calorimeter, which is identical to the calorimeter for prior CREAM balloon flights, provides energy measurements. In addition, scintillator-based Top and Bottom Counting Detectors distinguish electrons from nuclei. Our analysis indicates that the data extend well above 100 TeV. Recent results from the ongoing analysis are presented.
Ključne besede: ISS-CREAM, silicon charge detector, calorimeter, direct detection, cosmic rays, electrons, energy spectrum, composition
Objavljeno v RUNG: 26.09.2023; Ogledov: 995; Prenosov: 6
.pdf Celotno besedilo (901,39 KB)
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73.
Cosmic-ray Heavy Nuclei Spectra Using the ISS-CREAM Instrument
S.C. Kang, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) was designed to study high-energy cosmic rays up to PeV and recorded data from August 22nd, 2017 to February 12th, 2019 on the ISS. In this analysis, the Silicon Charge Detector (SCD), CALorimeter (CAL), and Top and Bottom Counting Detectors (TCD/BCD) are used. The SCD is composed of four layers and provides the measurement of cosmic-ray charges with a resolution of ∼0.2e. The CAL comprises 20 interleaved tungsten plates and scintillators, measures the incident cosmic-ray particles' energies, and provides a high energy trigger. The TCD/BCDs consist of photodiode arrays and plastic scintillators and provide a low-energy trigger. In this analysis, the SCD top layer is used for charge determination. Here, we present the heavy nuclei analysis using the ISS-CREAM instrument.
Ključne besede: ISS-CREAM, silicon charge detector, calorimeter, direct detection, heavy nuclei, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 26.09.2023; Ogledov: 927; Prenosov: 5
.pdf Celotno besedilo (1,82 MB)
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74.
Beam Test Results of the ISS-CREAM Calorimeter
H.G. Zhang, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Cosmic Ray Energetics And Mass experiment for the International Space Station (ISS-CREAM) was installed on the ISS to measure high-energy cosmic-ray elemental spectra for the charge range Z=1 to 26. The ISS-CREAM instrument includes a tungsten scintillating-fiber calorimeter preceded by carbon targets for energy measurements. The carbon targets induces hadronic interactions, and showers of secondary particles develop in the calorimeter. The calorimeter was calibrated with electron beams at CERN. This beam test included position, energy, and angle scans of electron and pion beams together with a high-voltage scan for calibration and characterization. Additionally, an attenuation effect in the scintillating fibers was studied. In this paper, beam test results, including corrections for the attenuation effect, are presented.
Ključne besede: ISS-CREAM, calorimeter, particle accelerator, CERN, electron beam, direct detection, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 26.09.2023; Ogledov: 903; Prenosov: 4
.pdf Celotno besedilo (1003,73 KB)
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75.
76.
Recent progress and applications of thermal lens spectrometry and photothermal beam deflection techniques in environmental sensing
Mladen Franko, Leja Goljat, Mingqiang Liu, Hanna Budasheva, Mojca Žorž, Dorota Korte, 2023, izvirni znanstveni članek

Opis: This paper presents recent development and applications of thermal lens microscopy (TLM) and beam deflection spectrometry (BDS) for the analysis of water samples and sea ice. Coupling of TLM detection to a microfluidic system for flow injection analysis (µFIA) enables the detection of microcystin-LR in waters with a four samples/min throughput (in triplicate injections) and provides an LOD of 0.08 µg/L which is 12-times lower than the MCL for microcystin-LR in water. µFIA-TLM was also applied for the determination of total Fe and Fe(II) in 3 µL samples of synthetic cloudwater. The LODs were found to be 100 nM for Fe(II) and 70 nM for total Fe. The application of µFIA-TLM for the determination of ammonium in water resulted in an LOD of 2.3 µM for injection of a 5 µL sample and TLM detection in a 100 µm deep microfluidic channel. For the determination of iron species in sea ice, the BDS was coupled to a diffusive gradient in the thin film technique (DGT). The 2D distribution of Fe(II) and total Fe on DGT gels provided by the BDS (LOD of 50 nM) reflected the distribution of Fe species in sea ice put in contact with DGT gels.
Ključne besede: thermal lens microscopy, beam deflection spectrometry, microfluidic system, microcystin-LR detection, iron species determination, ammonium detection
Objavljeno v RUNG: 03.01.2023; Ogledov: 1678; Prenosov: 24
.pdf Celotno besedilo (2,90 MB)
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77.
78.
On velocity-dependent dark matter annihilations in dwarf satellites
Mihael Petač, Piero Ullio, Mauro Valli, 2018, izvirni znanstveni članek

Opis: Milky Way dwarf spheroidal satellites are a prime target for Dark Matter (DM) indirect searches. There have been recent reassessments of the expected DM gamma-ray signals in case of long-range interactions, commonly known as Sommerfeld enhancement. Since details of the underlying DM phase-space distribution function become critical, there are potentially large uncertainties in the final result. We provide here a first attempt towards a comprehensive investigation of these systematics, addressing the impact on the expected DM flux from Milky Way dwarfs via Bayesian inference on the available stellar kinematic datasets. After reconsidering the study case of ergodic systems, we investigate for the first time scenarios where DM particle orbits may have a radial or tangential bias. We consider both cuspy and cored parametric DM density profiles, together with the case of a non-parametric halo modelling directly connected to line-of-sight observable quantities. The main findings of our work highlight the relevance of the assumed phase-space distribution: Referring to a generalized J-factor, namely the line-of-sight convolution of the spatial part in case of velocity-dependent annihilation rate, an enhancement (suppression) with respect to the limit of isotropic phase-space distributions is obtained for the case of tangentially (radially) biased DM particle orbits. We provide new estimates for J-factors for the eight brightest Milky Way dwarfs also in the limit of velocity-independent DM annihilation, in good agreement with previous results in literature, and derive data-driven lower-bounds based on the non-parametric modelling of the halo density. The outcome of our broad study stands out as a representative of the state-of-the-art in the field, and falls within the interest of current and future experimental collaborations involved in DM indirect detection programs.
Ključne besede: dark matter, indirect detection, dwarf satellites, sommerfeld enhancement, gamma-rays
Objavljeno v RUNG: 01.10.2021; Ogledov: 1879; Prenosov: 44  (1 glas)
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79.
Design & analysis of clustering based intrusion detection schemes for e-governance
Rajan Gupta, Sunil K. Muttoo, Saibal K. Pal, 2016, objavljeni znanstveni prispevek na konferenci

Opis: The problem of attacks on various networks and information systems is increasing. And with systems working in public domain like those involved under E-Governance are facing more problems than others. So there is a need to work on either designing an altogether different intrusion detection system or improvement of the existing schemes with better optimization techniques and easy experimental setup. The current study discusses the design of an Intrusion Detection Scheme based on traditional clustering schemes like K-Means and Fuzzy C-Means along with Meta-heuristic scheme like Particle Swarm Optimization. The experimental setup includes comparative analysis of these schemes based on a different metric called Classification Ratio and traditional metric like Detection Rate. The experiment is conducted on a regular Kyoto Data Set used by many researchers in past, however the features extracted from this data are selected based on their relevance to the E-Governance system. The results shows a better and higher classification ratio for the Fuzzy based clustering in conjunction with meta-heuristic schemes. The development and simulations are carried out using MATLAB.
Ključne besede: particle swarm optimization, intrusion detection, anomaly detection, intrusion detection system, network intrusion detection
Objavljeno v RUNG: 02.04.2021; Ogledov: 2297; Prenosov: 9
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80.
Development of e-governance in an emerging economy like India : assessment and way ahead for key components
Rajan Gupta, Sunil K. Muttoo, Saibal K. Pal, 2017, objavljeni znanstveni prispevek na konferenci

Opis: In this paper, we describe the key research questions handled during the doctoral work done in the area of E-Governance. The five research questions in the study are related to the concepts like Development of E-Governance & its assessment, Infrastructure management to reach out to maximum citizens, Various types of Security concerns faced during the E-Governance Development, Analyzing the E-Governance transaction pattern to capture citizen's interest, and finally the way ahead for the E-Governance development through the route of efficiency and optimization in the service designing. The methodology adopted and results obtained for various research questions are discussed at high level. Some portion of the current work is still in progress.
Ključne besede: e-governance, location allocation, common service centers, intrusion detection system, security, analytics
Objavljeno v RUNG: 02.04.2021; Ogledov: 2212; Prenosov: 56
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