A Stochastic Geometry Framework for LOS/NLOS Propagation in Dense Small Cell Networks

The need to carry out analytical studies of wireless systems often motivates the usage of simplified models which, despite their tractability, can easily lead to an overestimation of the achievable performance. In the case of dense small cells networks, the standard single slope path-loss model has been shown to provide interesting, but supposedly too optimistic, properties such as the invariance of the outage/coverage probability and of the spectral efficiency to the base station density. This paper seeks to explore the performance of dense small cells networks when a more accurate path-loss model is taken into account. We first propose a stochastic geometry based framework for small cell networks where the signal propagation accounts for both the Line-of-Sight (LOS) and Non-Line-Of-Sight (NLOS) components, such as the model provided by the 3GPP for evaluation of pico-cells in Heterogeneous Networks. We then study the performance of these networks and we show the dependency of some metrics such as the outage/coverage probability, the spectral efficiency and Area Spectral Efficiency (ASE) on the base station density and on the LOS likelihood of the propagation environment. Specifically, we show that, with LOS/NLOS propagation, dense networks still achieve large ASE gain but, at the same time, suffer from high outage probability.Comment: Typo corrected in eq. (3); Typo corrected in legend of Fig. 1-2; Typos corrected and definitions of some variables added in Section III.E; Final result unchanged; Paper accepted to IEEE ICC 201

Role of the polygalacturonate network on the iron (III) reduction by caffeic acid

This communication reports the role of polygalacturonate network on the Fe(III) reduction by caffeic acid. The effect of phosphate ions on the redox reaction is also considered

Beware of contagion!

Landscape ecology starts from the assumption that diversity and spatial arrangement of ecosystem mosaics has ecological implications and tries to understand the interactions between diversity and structure of large spatially heterogeneous areas and its ecological functions. This approach implies effective use of earth observation techniques and geographic information systems, enabling a global view of the landscape mosaics. Consequently, a large number of indices has been used to quantify the structure of categorical maps as a surrogate of actual landscapes and correlate them to ecological processes. In particular, the entropy-based contagion index has been extensively used to summarize the amount of clumping or fragmentation of patches on raster categorical maps. However, despite its widespread application, the contagion index is very dependent on pixel resolution. This effect may render it inadequate as a meaningful measure of landscape structure. To overcome this major shortcoming, in this short note we propose to quantify pixel adjacency with a bivariate summary statistics that is not adversely influenced by pixel resolution.L'articolo è disponibile sul sito dell'editore www.elsevier.co

Unlocking the deployment of spectrum sharing with a policy enforcement framework

Spectrum sharing has been proposed as a promising way to increase the efficiency of spectrum usage by allowing incumbent operators (IOs) to share their allocated radio resources with licensee operators (LOs), under a set of agreed rules. The goal is to maximize a common utility, such as the sum rate throughput, while maintaining the level of service required by the IOs. However, this is only guaranteed under the assumption that all “players”respect the agreed sharing rules. In this paper, we propose a comprehensive framework for licensed shared access (LSA) networks that discourages LO misbehavior. Our framework is built around three core functions: misbehavior detection via the employment of a dedicated sensing network; a penalization function; and, a behavior-driven resource allocation. To the best of our knowledge, this is the first time that these components are combined for the monitoring/policing of the spectrum under the LSA framework. Moreover, a novel simulator for LSA is provided as an open access tool, serving the purpose of testing and validating our proposed techniques via a set of extensive system-level simulations in the context of mobile network operators, where IOs and several competing LOs are considered. The results demonstrate that violation of the agreed sharing rules can lead to a great loss of resources for the misbehaving LOs, the amount of which is controlled by the system. Finally, we promote that including a policy enforcement function as part of the spectrum sharing system can be beneficial for the LSA system, since it can guarantee compliance with the spectrum sharing rules and limit the short-term benefits arising from misbehavior

Testi pahlavī dal codice MK. Edizione critica, traduzione e commento

La tesi dottorale intitolata “Testi pahlavī dal codice MK” offre l’edizione critica di diciassette componimenti pahlavī contenuti nel codice siglato MK, insieme con la loro traslitterazione, trascrizione e traduzione. Un regesto introduttivo per ogni testo fornisce i dati più propriamente culturali e letterari ricavabili dallo studio delle opere e del loro genere (handarz o sapienziale, ēwēn-namag o precettistico), mentre un esteso apparato di note di commento contestualizza le informazioni codicologiche e paleografiche derivate dall’analisi dei diversi manoscritti impiegati per la collazione. Le edizioni dei componimenti di MK finora pubblicate non hanno potuto presentare un’analisi critica dei testi per l’indisponibilità del codice, ritenuto perso dall’epoca della pubblicazione a stampa a fine Ottocento. Il presente lavoro, invece, giovandosi della visione diretta di MK e di altri cinque codici più un’importante collazione moderna, propone per la prima volta una disamina impostata secondo criteri filologicamente accurati. Un altro importante risultato dell'opera, inoltre, è stato quello di definire un preciso contesto cronologico e autoriale non soltanto dei testi contenuti in MK ma anche del codice stesso, prendendo in considerazione in maniera critica tutte le informazioni ricavabili dai suoi colofoni e dalle sottoscrizioni delle sue copie più recenti. Il lavoro, dunque, rimarca in generale l’importanza di un’analisi accurata della tradizione manoscritta, sia dal punto di vista materiale sia da quello contenutistico, per le future edizioni critiche di testi pahlavī

Fair and Regulated Spectrum Allocation in Licensed Shared Access Networks

We propose a novel Licensed Shared Access (LSA) spectrum allocation framework in this paper. The spectrum is made available to the licensee mobile network operators (MNOs) at specific time instants, in a specific service area, and for a specific time period. We propose a spectrum allocation algorithm which aims at providing resources to the MNOs in such a way that they can utilize them to serve their users and the resource allocation is fair at the same time. We also introduce a penalty mechanism whose output is a reduced spectrum allocation for the MNOs which violate the LSA spectrum use regulations. Our proposed algorithms are evaluated numerically and our results show that we can both guarantee fairness in spectrum allocation and penalize the MNOs that misbehave in regards to the LSA spectrum usage limitations imposed by the incumbent