GAN for Recommendation System Prosvetov, A. V.
Journal of physics. Conference series,
11/2019, Letnik:
1405, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In our day there are many approaches for recommendation generation, however several unsolved problems still exist. In our work we study the potential of Generative Adversarial Networks to generate ...relevant recommendations and compare the proposed approach with another recommendations system based on neural networks. We found that recommendation system based on GANs can successively compete with state-of-the-art network in the field of recommendation generation and suggest, that GAN recommendation system have high potential.
In our day many prediction models require to encode the series of events in a way that will allow to train the model and obtain the highest quality of predictions. The encoding of events depends on ...data domain and applied methods, however one can use neural network to encode the series of actions and obtain informative features for predictive models. We compared several architectures of neural networks in a task of feature extraction for predictive models. The comparison of architectures of neural networks was obtained on the field of sequence modeling, where the popularity of LSTM networks is dominant. We found, that the usage of appropriate event encoding allows to improve the quality of CNN based networks without using the modification of architectures.
We present the results of our analysis of the JEM-X/INTEGRAL data obtained from January 2003 to January 2015 aimed at searching for type I X-ray bursts from known and new bursters. Such bursts are ...caused by thermonuclear explosions on the surface of a neutron star. We have searched for bursts in the records of the count rate of the JEM-X detectors in the 3–20 keV energy band. We have separately reconstructed and analyzed the light curves of 104 X-ray bursters known to date based on the JEM-X data. A similar search for bursts was previously carried out in the 15–25 keV data from the IBIS/ISGRI telescope onboard the INTEGRAL observatory obtained in 2003–2009. We have continued to analyze the data from this telescope up until the observations in January 2015. The joint catalog of bursts detected by the two instruments includes 2201 events; their basic parameters are given. The large size of the sample of bursts makes it one of the most representative of the existing one and allows various statistical studies of bursts to be performed. In particular, we have constructed the dependence of the mean rate of type I bursts from bursters on the luminosity (accretion rate), revealed an appreciable burst rate from sources with a near-Eddington luminosity, and investigated the population of multiple bursts with a recurrence time much shorter than the time it takes for a critical mass of matter required for the initiation of an explosion to be accumulated on the neutron star surface. Almost all of the detected bursts are associated with already known bursters,we have found only one previously unknown burster, IGRJ17380-3749, in the archival data, and one more known, but poorly studied source, AX J1754.2-2754, has been identified as a burster. Several similar sources have previously been identified as bursters directly during the INTEGRAL observations.
We report the discovery of low-frequency quasi-periodic oscillations (QPOs) in the power spectrum of the X-ray nova MAXI J1535-571 at the initial stage of its outburst in September 2017. Based on ...data from the SWIFT and INTEGRAL instruments, we have traced the evolution of the QPO parameters (primarily their frequency) with time and their correlation with changes in the X-ray spectrum of the source (changes in the emission flux and hardness). We place constraints on the theoretical QPO generation models.
Recent Progress in the VEPP-2000 Collider Rastigeev, S. A.; Aktershev, Yu. S.; Bedarev, E. V. ...
Physics of particles and nuclei letters,
08/2023, Letnik:
20, Številka:
4
Journal Article
Recenzirano
The VEPP-2000 is an electron–positron collider with round beams built and operating at the Budker Institute of Nuclear Physics (BINP). The collider luminosity was increased twofold last year. The ...integrated luminosity accumulated over the last year has exceeded 0.3 fb
–1
, which almost doubled the total data collected since the collider operation began. The short description of the VEPP-2000 complex, current status, and the results are presented in this work.
Based on data from the SWIFT, INTEGRAL, MAXI/ISS orbital observatories, and the ground-based RTT-150 telescope, we have investigated the broadband (from the optical to the hard X-ray bands) spectrum ...of the X-ray nova MAXI J1828-249 and its evolution during the outburst of the source in 2013–2014. The optical and infrared emissions from the nova are shown to be largely determined by the extension of the power-law component responsible for the hard X-ray emission. The contribution from the outer cold regions of the accretion disk, even if the X-ray heating of its surface is taken into account, turns out to be moderate during the source’s “high” state (when a soft blackbody emission component is observed in the X-ray spectrum) and is virtually absent during its “low” (“hard”) state. This result suggests that much of the optical and infrared emissions from such systems originates in the same region of main energy release where their hard X-ray emission is formed. This can be the Compton or synchro-Compton radiation from a high-temperature plasma in the central accretion disk region puffed up by instabilities, the synchrotron radiation from a hot corona above the disk, or the synchrotron radiation from its relativistic jets.
Based on long-term SWIFT, RXTE, and MAXI observations of the X-ray novae H 1743-322 (IGR J17464-3213) and GX 339-4, we have investigated the morphology and classified the light curves of their X-ray ...outbursts. In particular, we have confirmed the existence of two radically different types of outbursts, soft (S) and hard (H), in both sources and revealed their varieties, ultrabright (U) and intermediate (I). The properties and origin of the differences in the light curves of these outbursts are discussed in terms of the truncated accretion disk model.
Objective. To determine in an experimental study the nature of changes in the status of the thiol-disulfide system of rats with encephalopathy, due to the influence of complex of anti-tuberculosis ...drugs for the treatment of chemoresistant tuberculosis and the possibility of their drug correction with the use of ademetionine 1,4-butanedisulfonate. Materials and methods. The study was conducted on 30 Wistar rats, which were divided into 3 groups: 10 – intact group, 10 – control group (treated with antituberculosis drugs) and 10 – main group (treated with antituberculosis drugs and ademetionine as means of correcting toxic effects). The state of the glutathione system and the content of homocysteine and nitrotyrosine were investigated. Results. Experimental therapy with ademetionine in rats treated with antituberculosis drugs helps to reduce the intensity of chronic oxidative stress in nerve tissue. The introduction of ademetionine establishes the most optimal ratio between the levels of reduced and oxidized thiol groups, as well as glutathione, which indicates the active mobilization of the thiol-disulfide system and the neutralization of products of free-radical oxidation. Under the conditions of nitrosative and oxidative stress, the studied agents increase the resistance of nervous tissue to the manifestations of intoxication. Thus, one of the links of the neuroprotective effect of ademetionin was its ability to stabilize the thiol-disulfide equilibrium. Conclusions. In the functioning of the glutathione-dependent enzymatic system in the tissues of the brain of rats treated with anti-tuberculosis drugs, there was decreased activity of glutathione s-transferase, glutathione peroxidase and glutathione reductase by 2.0, 1.7 and 2.4 times, respectively. Under the conditions of ademetionin therapy, there was increase by 1.7 times in the reduced intermediates of the thiol-disulfide system – SH-group, and an increase of the level of reduced glutathione by 1.9 times, against the background of a significant decrease in the content of its oxidized form – 1.4 times. The use of ademetionin also led to a decrease of the content of potentially neurotoxic compounds - nitrotyrosine and homocysteine by 1.4 and 1.5 times, respectively in the brain tissues, which increases the resistance of nervous tissue to the effects of intoxication.
Results of the study of the X-ray nova SWIFT J174510.8-262411 by the INTEGRAL, SWIFT, and VLA observatories in September–October 2012 at the early outburst phase are presented. Attention is focused ...on analyzing the power spectrum of X-ray flux fluctuations of the source in which a powerful quasi-periodic oscillation (QPO) peak has been detected. The evolution of the QPO peak parameters with time has been traced; a correlation between the QPO frequency, low-frequency noise (LFN) parameters, X-ray and radio fluxes, and fractional polarization of radio emission has been revealed. The fractal properties of the source’s light curves in the standard X-ray band (<10 keV) are shown to change with QPO peak frequency. In the hard X-ray band (20–80 keV), the source’s light curves have no fractal properties, despite the larger QPO and LFN amplitude than that in the standard X-ray band. The observational results can be explained by assuming that the source’s X-ray emission is formed in a hot plasma cloud surrounding a black hole, while the QPOs are produced at its boundary, at the place of contact with the accretion disk; their frequency reflects the Keplerian rotation of matter at the corresponding radius.
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