The Approximate Optimality of Simple Schedules for Half-Duplex Multi-Relay Networks

In ISIT'12 Brahma, \"{O}zg\"{u}r and Fragouli conjectured that in a half-duplex diamond relay network (a Gaussian noise network without a direct source-destination link and with $N$ non-interfering relays) an approximately optimal relay scheduling (achieving the cut-set upper bound to within a constant gap uniformly over all channel gains) exists with at most $N+1$ active states (only $N+1$ out of the $2^N$ possible relay listen-transmit configurations have a strictly positive probability). Such relay scheduling policies are said to be simple. In ITW'13 we conjectured that simple relay policies are optimal for any half-duplex Gaussian multi-relay network, that is, simple schedules are not a consequence of the diamond network's sparse topology. In this paper we formally prove the conjecture beyond Gaussian networks. In particular, for any memoryless half-duplex $N$-relay network with independent noises and for which independent inputs are approximately optimal in the cut-set upper bound, an optimal schedule exists with at most $N+1$ active states. The key step of our proof is to write the minimum of a submodular function by means of its Lov\'{a}sz extension and use the greedy algorithm for submodular polyhedra to highlight structural properties of the optimal solution. This, together with the saddle-point property of min-max problems and the existence of optimal basic feasible solutions in linear programs, proves the claim.Comment: Submitted to IEEE Information Theory Workshop (ITW) 201

Efficiently Finding Simple Schedules in Gaussian Half-Duplex Relay Line Networks

The problem of operating a Gaussian Half-Duplex (HD) relay network optimally is challenging due to the exponential number of listen/transmit network states that need to be considered. Recent results have shown that, for the class of Gaussian HD networks with N relays, there always exists a simple schedule, i.e., with at most N +1 active states, that is sufficient for approximate (i.e., up to a constant gap) capacity characterization. This paper investigates how to efficiently find such a simple schedule over line networks. Towards this end, a polynomial-time algorithm is designed and proved to output a simple schedule that achieves the approximate capacity. The key ingredient of the algorithm is to leverage similarities between network states in HD and edge coloring in a graph. It is also shown that the algorithm allows to derive a closed-form expression for the approximate capacity of the Gaussian line network that can be evaluated distributively and in linear time. Additionally, it is shown using this closed-form that the problem of Half-Duplex routing is NP-Hard.Comment: A short version of this paper was submitted to ISIT 201

On the Capacity of the Two-user Gaussian Causal Cognitive Interference Channel

This paper considers the two-user Gaussian Causal Cognitive Interference Channel (GCCIC), which consists of two source-destination pairs that share the same channel and where one full-duplex cognitive source can causally learn the message of the primary source through a noisy link. The GCCIC is an interference channel with unilateral source cooperation that better models practical cognitive radio networks than the commonly used model which assumes that one source has perfect non-causal knowledge of the other source's message. First the sum-capacity of the symmetric GCCIC is determined to within a constant gap. Then, the insights gained from the derivation of the symmetric sum-capacity are extended to characterize the whole capacity region to within a constant gap for more general cases. In particular, the capacity is determined (a) to within 2 bits for the fully connected GCCIC when, roughly speaking, the interference is not weak at both receivers, (b) to within 2 bits for the Z-channel, i.e., when there is no interference from the primary user, and (c) to within 2 bits for the S-channel, i.e., when there is no interference from the secondary user. The parameter regimes where the GCCIC is equivalent, in terms of generalized degrees-of-freedom, to the noncooperative interference channel (i.e., unilateral causal cooperation is not useful), to the non-causal cognitive interference channel (i.e., causal cooperation attains the ultimate limit of cognitive radio technology), and to bilateral source cooperation are identified. These comparisons shed lights into the parameter regimes and network topologies that in practice might provide an unbounded throughput gain compared to currently available (non cognitive) technologies.Comment: Under second round review in IEEE Transactions in Information Theory - Submitted September 201

Orientare tra formazione e lavoro: bilancio di competenze e servizi di placement all’Universitá di Foggia

As características da sociedade atual e as mais recentes publicações nacionais e internacionais mostram que a orientação é um processo de valor educacional superior e e é concebido como um sistema integrado ao longo da vida. As instituições de ensino têm um papel importante no que se refere à promoção da orientação, especialmente as universidades. A partir dessas premissas, a "Skills Laboratory Balance" de Foggia (Itália) fornece e executa diversos serviços para promover habilidades de orientação, com especial atenção para a pessoa e ao cidadão para o futuro profissional

Preserving biodiversity as source of health promoting compounds: Phenolic profile and biological activity of four varieties of solanum lycopersicum l

Tomato (Solanum lycopersicum L.) is a precious source of specialized metabolites with a great role in human health. Many varieties of tomatoes characterize the south of Italy’s agronomic production and biodiversity, thanks to its warm temperatures and favorable weather. The preser-vation of biodiversity is a major goal of recent years, as each variety shows a peculiar phytochemical profile and provides a wide variety of metabolites with health‐beneficial properties. Among the wide range of tomato varieties, literature focused on the most commercially‐known types, including San Marzano and Datterino, while this study considered typical South Italy varieties for the first time, as well as Crovarese and Arsicolo. The aim of our work is to enrich the current knowledge about the tomato by evaluating the carotenoid content, the phytochemical profile by HPLC‐DAD, and the biological activity of the different parts (peel, fruit, pulp, and seeds) of niche cultivars compared with commercial ones. Radical scavenging activity, assessed by the 2,2‐Diphenyl‐1‐picrylhy-drazyl (DPPH) method, was higher in Crovarese peel extract, while Arsicolo possessed the highest lycopene content, underlying the importance of local ecotypes as a precious source of health promoting compounds. However, out of all of the varieties considered, peel extract was the most active one, opening new insights on their valorization in light of the circular economy

Facilitating the Child–Robot Interaction by Endowing the Robot with the Capability of Understanding the Child Engagement: The Case of Mio Amico Robot

AbstractSocial Robots (SRs) are substantially becoming part of modern society, given their frequent use in many areas of application including education, communication, assistance, and entertainment. The main challenge in human–robot interaction is in achieving human-like and affective interaction between the two groups. This study is aimed at endowing SRs with the capability of assessing the emotional state of the interlocutor, by analyzing his/her psychophysiological signals. The methodology is focused on remote evaluations of the subject's peripheral neuro-vegetative activity by means of thermal infrared imaging. The approach was developed and tested for a particularly challenging use case: the interaction between children and a commercial educational robot, Mio Amico Robot, produced by LiscianiGiochi©. The emotional state classified from the thermal signal analysis was compared to the emotional state recognized by a facial action coding system. The proposed approach was reliable and accurate and favored a personalized and improved interaction of children with SRs