The Gaussian streaming model and Lagrangian effective field theory

We update the ingredients of the Gaussian streaming model (GSM) for the redshift-space clustering of biased tracers using the techniques of Lagrangian perturbation theory, effective field theory (EFT) and a generalized Lagrangian bias expansion. After relating the GSM to the cumulant expansion, we present new results for the real-space correlation function, mean pairwise velocity and pairwise velocity dispersion including counter terms from EFT and bias terms through third order in the linear density, its leading derivatives and its shear up to second order. We discuss the connection to the Gaussian peaks formalism. We compare the ingredients of the GSM to a suite of large N-body simulations, and show the performance of the theory on the low order multipoles of the redshift-space correlation function and power spectrum. We highlight the importance of a general biasing scheme, which we find to be as important as higher-order corrections due to non-linear evolution for the halos we consider on the scales of interest to us.Comment: 28 pages, 5 figures. Revised to match version accepted by journa

Testing of mobile networks with help of ROMES program

Tato práce se zabývá možnostmi využití programu ROMES firmy Rohde & Schwarz pro testování mobilních telekomunikačních sítí. Zaměřuje se na dnes aktivní a nově zaváděné systémy GSM (Groupe Spécial Mobile), UMTS (Universal Mobile Telecommunication System), LTE (Long Term Evolution).This thesis examines the posibilities of programe ROMES by Rohde & Schwarz for testing mobile telecomunication systems. Thesis is focused on active and recently implemented systems GSM (Groupe Spécial Mobile), UMTS (Universal Mobile Telecommunication System) LTE (Long Term Evolution).

Comparative Analysis of GSM and CDMA, Strength and Weakness, Future Challenges and Practical Solutions (A Case Study of MTN and NITEL Nigeria

Considering the strength, weakness, future challenges and practical solutions of GSM and CDMAA, this paper comprehensively compares GSM and CDMA by making use of telecommunication service operators in Nigeria as a case study. The paper starts with the review of telecommunication system in Nigeria by looking at the history of telecommunication in Nigeria, the evolution of cellular communication architecture, GSM and CDMA technology and presentation of a comparative analysis between GSM and CDMA. The services of GSM telecommunication operators in Nigeria were compared with the CDMA operators. Finally emphasis is laid on the duo of MTN and NITEL. Two Urban Cities were chosen in South west of Nigeria (namely: Lagos and Ibadan). Chi-square test statistic is implored to investigate the subscribers’ response on the type of services they enjoyed on their mobile phone. The discussion of result is presented based on the analysis of data extracted from the responses from the respondents and recommendations are made for further studies. Keywords: NITEL, CDMA, GSM, Cell, Cellular, EDGE, 1G, 2G, 3G, telecom

Gamow shell model description of radiative capture reactions 6^6Li(p,γ)(p,\gamma)7^7Be and 6^6Li(n,γ)(n,\gamma)7^7Li

According to standard stellar evolution, lithium abundance is believed to be a useful indicator of the stellar age. However, many evolved stars like red giants show huge fluctuations around expected theoretical abundances that are not yet fully understood. The better knowledge of nuclear reactions that contribute to the creation and destruction of lithium can help to solve this puzzle. In this work we apply the Gamow shell model (GSM) formulated in the coupled-channel representation (GSM-CC) to investigate the mirror radiative capture reactions $^6$Li$(p,\gamma)$$^7$Be and $^6$Li$(n,\gamma)$$^7$Li. The cross-sections are calculated using a translationally invariant Hamiltonian with the finite-range interaction which is adjusted to reproduce spectra, binding energies and one-nucleon separation energies in $^{6-7}$Li, $^7$Be. All relevant $E1$, $M1$, and $E2$ transitions from the initial continuum states to the final bound states $J={3/2}_1^-$ and $J={1/2}^-$ of $^7$Li and $^7$Be are included. We demonstrate that the $s$-wave radiative capture of proton (neutron) to the first excited state $J^{\pi}=1/2_1^+$ of $^7$Be ($^7$Li) is crucial and increases the total astrophysical $S$-factor by about 40 \%.Comment: arXiv admin note: text overlap with arXiv:1502.0163

Wireless Cellular Mobile Communications

In this article is briefly reviewed the history of wireless cellular mobile communications, examined the progress in current second generation (2G) cellular standards and discussed their migration to the third generation (3G). The European 2G cellular standard GSM and its evolution phases GPRS and EDGE are described somewhat in detail. The third generation standard UMTS taking up on GSM/GPRS core network and equipped with a new advanced access network on the basis of code division multiple access (CDMA) is investigated too. A sketch of the perspective of mobile communication beyond 3G concludes this article

Public mobile wideband networks interference impact assessment on railways GSM-R network

This paper presents a field study relating to the impact that public operator cellular networks such as UMTS (Universal Mobile Telecommunication System), LTE (Long-Term Evolution), and 5G-NR (5G - New Radio) have on railway GSM-R (Global System for Mobile Communications – Railway) networks. The validation of the interference calculation relied on actual network measurements taken along railway lines using a dedicated probe. Emissions from public networks, in some scenarios, have been shown to affect GSM-R networks to a large extent. The developed algorithm is currently being used in real GSM-R network planning to mitigate this negative effect on base station coverage and service performance.info:eu-repo/semantics/publishedVersio

Quality assessment and usage behavior of a mobile voice-over-IP service

Voice-over-IP (VoIP) services offer users a cheap alternative to the traditional mobile operators to make voice calls. Due to the increased capabilities and connectivity of mobile devices, these VoIP services are becoming increasingly popular on the mobile platform. Understanding the user's usage behavior and quality assessment of the VoIP service plays a key role in optimizing the Quality of Experience (QoE) and making the service to succeed or to fail. By analyzing the usage and quality assessments of a commercial VoIP service, this paper identifies device characteristics, context parameters, and user aspects that influence the usage behavior and experience during VoIP calls. Whereas multimedia services are traditionally evaluated by monitoring usage and quality for a limited number of test subjects and during a limited evaluation period, this study analyzes the service usage and quality assessments of more than thousand users over a period of 120 days. This allows to analyze evolutions in the usage behavior and perceived quality over time, which has not been done up to now for a widely-used, mobile, multimedia service. The results show a significant evolution over time of the number of calls, the call duration, and the quality assessment. The time of the call, the used network, and handovers during the call showed to have a significant influence on the users' quality assessments