Determining the core radio luminosity function of radio AGNs via copula

The radio luminosity functions (RLFs) of active galactic nuclei (AGNs) are traditionally measured based on total emission, which doesn't reflect the current activity of the central black hole. The increasing interest in compact radio cores of AGNs requires determination of the RLF based on core emission (i.e., core RLF). In this work we have established a large sample (totaling 1207) of radio-loud AGNs, mainly consisting of radio galaxies (RGs) and steep-spectrum radio quasars (SSRQs). Based on the sample, we explore the relationship between core luminosity ($L_c$) and total luminosity ($L_t$) via a powerful statistical tool called "Copula". The conditional probability distribution $p(\log L_{c} \mid \log L_{t})$ is obtained. We derive the core RLF as a convolution of $p(\log L_{c} \mid \log L_{t})$ with the total RLF which was determined by previous work. We relate the separate RG and SSRQ core RLFs via a relativistic beaming model and find that SSRQs have an average Lorentz factor of $\gamma=9.84_{-2.50}^{+3.61}$, and that most are seen within $8^{\circ} \lesssim \theta \lesssim 45^{\circ}$ of the jet axis. Compared with the total RLF which is mainly contributed by extended emission, the core RLF shows a very weak luminosity-dependent evolution, with the number density peaking around $z\thicksim 0.8$ for all luminosities. Differences between core and total RLFs can be explained in a framework involving a combination of density and luminosity evolutions where the cores have significantly weaker luminosity evolution than the extended emission.Comment: Accepted for publication in the ApJ

Regenerative and Adaptive schemes Based on Network Coding for Wireless Relay Network

Recent technological advances in wireless communications offer new opportunities and challenges for relay network.To enhance system performance, Demodulate-Network Coding (Dm-NC) scheme has been examined at relay node; it works directly to De-map the received signals and after that forward the mixture to the destination. Simulation analysis has been proven that the performance of Dm-NC has superiority over analog-NC. In addition, the Quantize-Decode-NC scheme (QDF-NC) has been introduced. The presented simulation results clearly provide that the QDF-NC perform better than analog-NC. The toggle between analogNC and QDF-NC is simulated in order to investigate delay and power consumption reduction at relay node.Comment: 11 pages, 8 figures, International Journal of Computer Networks & Communications (IJCNC), Vol.4, No.3, May 201

Taxes and Unmarried Fathers’ Participation in the Underground Economy

In this paper we employ data from the Fragile Families and Child Well-Being Study in order to estimate a model of underground labor supply developed by Lemieux et al. (1994). We focus specifically on the underground labor supply of unmarried fathers, a group that is likely to have significant involvement in the underground economy. We also extend the empirical analysis of Lemieux et al. by taking into account exogenous state and local variation in marginal tax rates, as well as sociodemographic variables related to the likelihood of participation in the underground. In accordance with expectations, we find that a significant proportion of unmarried fathers report participation in the underground. However, although the theoretical model predicts a positive relationship between the tax rate and underground hours of work (under certain conditions), we find that the effect of the tax rate on hours is statistically indistinguishable from zero, even after including exogenous variation in tax rates. We also fail to find a positive and statistically significant effect of the tax rate on participation in the underground. Within the context of the model, these results have specific implications for the magnitudes of the probability of detection and the penalty on evaded tax. Therefore, we conclude that additional empirical information is needed regarding these parameters. Future research might also employ other datasets in the estimation of the theoretical model outlined by Lemieux et al., as well as investigate the applicability of other models of underground labor supply.