183 research outputs found
Study and analysis of innovative network protocols and architectures
In the last years, some new paradigms are emerging in the networking area as inspiring models for the definition of future communications networks. A key example is certainly the Content Centric Networking (CCN) protocol suite, namely a novel network architecture that aims to supersede the current TCP/IP stack in favor of a name based routing algorithm, also introducing in-network caching capabilities. On the other hand, much interest has been placed on Software Defined Networking (SDN), namely the set of protocols and architectures designed to make network devices more dynamic and programmable. Given this complex arena, the thesis focuses on the analysis of these innovative network protocols, with the aim of exploring possible design flaws and hence guaranteeing their proper operation when actually deployed in the network. Particular emphasis is given to the security of these protocols, for its essential role in every wide scale application. Some work has been done in this direction, but all these solutions are far to be considered fully investigated. In the CCN case, a closer investigation on problems related to possible DDoS attacks due to the stateful nature of the protocol, is presented along with a full-fledged proposal to support scalable PUSH application on top of CCN. Concerning SDN, instead, we present a tool for the verification of network policies in complex graphs containing dynamic network functions. In order to obtain significant results, we leverage different tools and methodologies: on the one hand, we assess simulation software as very useful tools for representing the most common use cases for the various technologies. On the other hand, we exploit more sophisticated formal methods to ensure a higher level of confidence for the obtained results
FIRST RECORD IN ITALY OF PSYLLAEPHAGUS BLITEUS RIEK (Hymenoptera Encyrtidae) PARASITOID OF GLYCASPIS BRIMBLECOMBEI MOORE (Hemiptera Psyllidae)
Psyllaephagus bliteus Riek (Hymenoptera Encyrtidae), parasitoid of the red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera Psyllidae), has been recorded for the first time in Italy in September 2011. The arrival of P. bliteus in Sicily is due to an accidental introduction, probably together with its host, as already happened in New Zealand, Brazil, Spain and Morocco
PIT Overload Analysis in Content Centric Networks
Content Centric Networking represents a paradigm shift in the evolution and definition of modern network protocols. Many research efforts have been made with the purpose of proving the feasibility and the scalability of this proposal. Our main contribution is to provide an analysis of the Pending Interest Table memory requirements in real deployment scenarios, especially considering the impact of distributed denial of service attacks. In fact, the state that the protocol maintains for each resource request makes the routers more prone to resources exhaustion issues than in traditional stateless solutions. Our results are derived by using a full custom simulator and considering the different node architectures that have been proposed as valid reference models. The main outcomes point out differentiated weaknesses in each architecture we investigated and underline the need for improvements in terms of security and scalabilit
Primi reperti in Sicilia su diffusione e biologia di Leptoglossus occidentalis Heidemann (Hetroptera: Coreidae), cimice americana dei semi delle conifere
In this paper the first data on the distribution and biology of L. occidentalis in Sicily are reported; this bug, belonging to the family Coreidae, originates from North America, where it is regarded as a serious pest of conifer seed orchards. The first Sicilian specimens of L. occidentalis were found in September 2002 near Gangi (PA), while the first collecting data published until now refer to November 2003 in Niscemi (CL). The coreid is distributed in all Sicily provinces (30 collecting sites), from the sea level to 1.430 m a.s.l. on the mountains; it was collected on cones and plants of Pinus halepensis Miller, P. laricio Poiret, P. pinea L., P. nigra J.F.Arnold and Pseudotsuga menziesii (Mirb.) Franco, and also inside or near buildings. Females fed in laboratory (at 22 °C ± 1 and 80% U.R.) on P. menziesii shoots layed up to 148 eggs, beginning oviposition after 3 days when collected at the end of May and after 73 days when collected in November. In the laboratory the oviposition period lasted 35 days on average; adults were obtained 61 days after oviposition.
Our field and laboratory data did not allow to ascertain the number of yearly generations of L. occidentalis in Sicily, but they should not be more than 2
Dannosità e controllo di Rhagoletis cerasi (L.) in ceraseti biologici della Sicilia occidentale.
Damage and control of Rhagoletis cerasi (L.) in organic cherry orchards in Western Sicily
The study was carried out in 2009, 2010 and 2011 in organic cherry orchards in Western Sicily, were the control of Rhagoletis cerasi (L.), the cherry fly, is a problem for medium-late ripening cultivars. Presence and infestation of the dipteran were monitored on local cultivars and the effectiveness of pyrethrum, allowed in organic farming, was tested, comparing it with net bags. The presence of the cherry fly was recorded in all cherry orchards except in one isolated and recently planted. The infestation on fruits was not very high; it was absent until the end of May. Nets drastically reduced the infestation, while pyrethrum was less effective in lowering it.
Riassunto
Lo studio è stato condotto nel 2009, 2010 e 2011 in ceraseti biologici della Sicilia Occidentale, dove il controllo di Rhagoletis cerasi (L.), mosca delle ciliegie, costituisce un problema per le cultivar a maturazione medio-tardiva. Sono state monitorate la presenza e le infestazioni del dittero, confrontando anche l’efficacia del piretro, ammesso in agricoltura biologica, con la protezione delle ciliegie con sacchi di rete. La presenza della mosca delle ciliegie è stata registrata in tutti i ceraseti, con l’unica eccezione di un ceraseto isolato e impiantato di recente. Le infestazioni nei frutti non sono state registrate fino alla fine di maggio, e anche dopo non sono risultate elevate. Le reti hanno ridotto drasticamente le infestazioni della mosca delle ciliegie, mentre il piretro è stato meno efficace nel controllarla
Targeted phenolic profile of radler beers by HPLC-ESI-MS/MS: the added value of hesperidin to beer antioxidants
The well-known health beneficial properties of beer are mainly due to phenolic antioxidants. Citrus-flavored beers represent a growing side-market in the beer industry, sparingly investigated to date. The phenolic profile of commercial radler beers (R1, R2) was investigated to evaluate the impact of the lemon juice added to beer in the industrial production. Results were compared to those obtained for opportunely chosen commercial beer (B) and lemonade (L). The study was carried out by an HPLC-MS/MS with an electrospray ionization source in selected ion recording mode, analyzing in a single chromatographic run 26 compounds belonging to the different phenolic classes of hydroxybenzoic, hydroxycinnamic and caffeoylquinic acids, flavonoids and prenylflavonoids. Different phenolic profiles were found for R1 and R2, mainly ascribed to different malt/hop/recipe used for the beer. High to very high level of hesperidin were found in the radlers, so that a major impact on phenolic antioxidants of the radlers was due to the lemon. Similarly, a major impact of the lemon aromas was found, D-limonene being the dominant peak resulting from the GC-MS analysis of the volatile fraction of the radlers. Graphical Abstract: [Figure not available: see fulltext.]
First data on the repellent activity of essential oils of Citrus limon towards medfly (Ceratitis capitata)
The biological activity of peel essential oils of two Sicilian cultivars of C. limon, ‘Interdonato’ and ‘Lunario’, was investigated by electrophysiological recordings (EAG) and field trials on Ceratitis capitata (Wiedemann) (Diptera Tephritidae). The EAG data showed a remarkable dose-response relationship and a low activation threshold dose (10-3M) for both essential oil extracts. In field tests, essential oils showed a good repellent and antiovipositional activi- ty on ‘Navelina’ oranges, and in particular the essential oils of ‘Lunario’ pro- vided the same results of kaolin. Potential applications of essential oils from C. limon cultivars against C. capitata in organic farming are discussed
FATIGUE ALTERS THE BIOMECHANICS OF TURNS WHILE RUNNING
This study identified the effects of fatigue on lower limb kinematics while running with repeated 180°-turns. An increased stiffness of the pivoting limb was observed in terms of a reduction of hip and knee flexion angles, and an increase of hip abduction and internal rotation. We concluded that muscle fatigue can trigger a sequence of adaptations that were previously found to expose the athlete to an increasing risk of ligament injury. These results expand the base of evidence for the development of field-based prevention programs
Testing general relativity by means of ring lasers
The paper discusses the optimal conguration of one or more ring lasers to be used for measuring
the general relativistic effects of the rotation of the Earth, as manifested on the surface of the planet. The
analysis is focused on devices having their normal vector lying in the meridian plane. The crucial role
of the evaluation of the angles is evidenced. Special attention is paid to the orientation at the maximum
signal, minimizing the sensitivity to the orientation uncertainty. The use of rings at different latitudes is
mentioned and the problem of the non-sphericity of the Earth is commented
Study of Innovative GO/PBI Composites as Possible Proton Conducting Membranes for Electrochemical Devices
The appeal of combining polybenzimidazole (PBI) and graphene oxide (GO) for the manufacturing of membranes is increasingly growing, due to their versatility. Nevertheless, GO has always been used only as a filler in the PBI matrix. In such context, this work proposes the design of a simple, safe, and reproducible procedure to prepare self-assembling GO/PBI composite membranes characterized by GO-to-PBI (X:Y) mass ratios of 1:3, 1:2, 1:1, 2:1, and 3:1. SEM and XRD suggested a homogenous reciprocal dispersion of GO and PBI, which established an alternated stacked structure by mutual π-π interactions among the benzimidazole rings of PBI and the aromatic domains of GO. TGA indicated a remarkable thermal stability of the composites. From mechanical tests, improved tensile strengths but worsened maximum strains were observed with respect to pure PBI. The preliminary evaluation of the suitability of the GO/PBI X:Y composites as proton exchange membranes was executed via IEC determination and EIS. GO/PBI 2:1 (IEC: 0.42 meq g−1; proton conductivity at 100 °C: 0.0464 S cm−1) and GO/PBI 3:1 (IEC: 0.80 meq g−1; proton conductivity at 100 °C: 0.0451 S cm−1) provided equivalent or superior performances with respect to similar PBI-based state-of-the-art materials
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