Search results for "Alphanumeric"
showing 6 items of 6 documents
Spin up and phase fluctuations in the timing of the accreting millisecond pulsar XTE J1807-294
2007
We performed a timing analysis of the 2003 outburst of the accreting X-ray millisecond pulsar XTE J1807-294 observed by RXTE. Using recently refined orbital parameters we report for the first time a precise estimate of the spin frequency and of the spin frequency derivative. The phase delays of the pulse profile show a strong erratic behavior superposed to what appears as a global spin-up trend. The erratic behavior of the pulse phases is strongly related to rapid variations of the light curve, making it very difficult to fit these phase delays with a simple law. As in previous cases, we have therefore analyzed separately the phase delays of the first harmonic and of the second harmonic of …
BeppoSAX serendipitous discovery of the X-ray pulsar SAX J1802.7-2017
2003
We report on the serendipitous discovery of a new X-ray source, SAX J1802.7-2017, ~22' away from the bright X-ray source GX 9+1, during a BeppoSAX observation of the latter source on 2001 September 16-20. SAX J1802.7-2017 remained undetected in the first 50 ks of observation; the source count rate in the following ~300 ks ranged between 0.04 c/s and 0.28 c/s, corresponding to an averaged 0.1-10 keV flux of 3.6 10^{-11} ergs cm^{-2} s^{-1}. We performed a timing analysis and found that SAX J1802.7-2017 has a pulse period of 139.612 s, a projected semimajor axis of a_x sin i ~ 70 lt-s, an orbital period of ~4.6 days, and a mass function f(M) ~ 17 Msun. The new source is thus an accreting X-ra…
User experience and the security of graphical passwords
2015
Graafiset salasanat ovat lupaava vaihtoehto alfanumeeriselle autentikaatiolle. Älypuhelinten ja muiden korkea resoluutioisten kosketusnäytöllisten laitteiden määrä on kasvussa ja alfanumeeriset salasanat ovat kehitetty alun perin näppäimistölle syötettäviksi. Tarkkuutta vaativa kirjoittaminen ei tällöin ole välttämättä käyttäjälle kaikkein mielekkäintä. Graafisia ja alfanumeerisia salasanoja on tutkittu muistin toiminnan sekä käytettävyyden näkökulmasta. Tutkielma on tehty kirjallisuuden pohjalta käyttäen apuna erilaisia tieteellisia julkaisuja sisältäviä tietokantoja, kuten IEE Explore ja ACM Digital Library - tietokantoja. Tutkielman tarkoituksena oli kuvata ja tutkia tieteellisten artikk…
Rapid automatized naming in early literacy
2019
Esta comunicación se encuentra disponible en la siguiente URL: http://www.infad.eu/RevistaINFAD/OJS/index.php/IJODAEP/article/view/1465/1274 Este número está dedicado a la "Psicología de la Educación y Saberes Originarios". Although the relation between Rapid Automatized Naming (RAN) and Reading is clear, there is no a standardized test to measure the speed of naming in early literacy. The aim is to explore and confirm the factorial structure of the RAN test developed by Wolf and Denkla (2003) in children. RAN test was administred to 442 children aged 4-5 years. Results highlighted two factors: a “nonalphanumeric components” factor which includes “RAN colors” and “RAN images” and an “alphan…
Enabling Searches on Wavelengths in a Hyperspectral Indices Database
2018
Abstract. Spectral indices derived from hyperspectral reflectance measurements are powerful tools to estimate physical parameters in a non-destructive and precise way for several fields of applications, among others vegetation health analysis, coastal and deep water constituents, geology, and atmosphere composition. In the last years, several micro-hyperspectral sensors have appeared, with both full-frame and push-broom acquisition technologies, while in the near future several hyperspectral spaceborne missions are planned to be launched. This is fostering the use of hyperspectral data in basic and applied research causing a large number of spectral indices to be defined and used in various…
Domain Generation Algorithm Detection Using Machine Learning Methods
2018
A botnet is a network of private computers infected with malicious software and controlled as a group without the knowledge of the owners. Botnets are used by cybercriminals for various malicious activities, such as stealing sensitive data, sending spam, launching Distributed Denial of Service (DDoS) attacks, etc. A Command and Control (C&C) server sends commands to the compromised hosts to execute those malicious activities. In order to avoid detection, recent botnets such as Conficker, Zeus, and Cryptolocker apply a technique called Domain-Fluxing or Domain Name Generation Algorithms (DGA), in which the infected bot periodically generates and tries to resolve a large number of pseudorando…