Network Infrastructures for Highly Distributed Cloud-Computing

Software-Defined-Network (SDN) is emerging as a solid opportunity for the Network Service Providers (NSP) to reduce costs while at the same time providing better and/or new services. The possibility to flexibly manage and configure highly-available and scalable network services through data model abstractions and easy-to-consume APIs is attractive and the adoption of such technologies is gaining momentum. At the same time, NSPs are planning to innovate their infrastructures through a process of network softwarisation and programmability. The SDN paradigm aims at improving the design, configuration, maintenance and service provisioning agility of the network through a centralised software control. This can be easily achievable in local area networks, typical of data-centers, where the benefits of having programmable access to the entire network is not restricted by latency between the network devices and the SDN controller which is reasonably located in the same LAN of the data path nodes. In Wide Area Networks (WAN), instead, a centralised control plane limits the speed of responsiveness in reaction to time-constrained network events due to unavoidable latencies caused by physical distances. Moreover, an end-to-end control shall involve the participation of multiple, domain-specific, controllers: access devices, data-center fabrics and backbone networks have very different characteristics and their control-plane could hardly coexist in a single centralised entity, unless of very complex solutions which inevitably lead to software bugs, inconsistent states and performance issues. In recent years, the idea to exploit SDN for WAN infrastructures to connect multiple sites together has spread in both the scientific community and the industry. The former has produced interesting results in terms of framework proposals, complexity and performance analysis for network resource allocation schemes and open-source proof of concept prototypes targeting SDN architectures spanning multiple technological and administrative domains. On the other hand, much of the work still remains confined to the academy mainly because based on pure Openflow prototype implementation, networks emulated on a single general-purpose machine or on simulations proving algorithms effectiveness. The industry has made SDN a reality via closed-source systems, running on single administrative domain networks with little if no diversification of access and backbone devices. In this dissertation we present our contributions to the design and the implementation of SDN architectures for the control plane of WAN infrastructures. In particular, we studied and prototyped two SDN platforms to build a programmable, intent-based, control-plane suitable for the today highly distributed cloud infrastructures. Our main contributions are: (i) an holistic and architectural description of a distributed SDN control-plane for end-end QoS provisioning; we compare the legacy IntServ RSVP protocol with a novel approach for prioritising application-sensitive flows via centralised vantage points. It is based on a peer-to-peer architecture and could so be suitable for the inter-authoritative domains scenario. (ii) An open-source platform based on a two-layer hierarchy of network controllers designed to provision end-to-end connectivity in real networks composed by heterogeneous devices and links within a single authoritative domain. This platform has been integrated in CORD, an open-source project whose goal is to bring data-center economics and cloud agility to the NSP central office infrastructures, combining NFV (Network Function Virtualization), SDN and the elasticity of commodity clouds. Our platform enables the provisioning of connectivity services between multiple CORD sites, up to the customer premises. Thus our system and software contributions in SDN has been combined with a NFV infrastructure for network service automation and orchestration

Probabilistic time variant assessment of thin-walled steel members under atmospheric corrosion attack

Atmospheric corrosion is a relevant problem for steel structures and components exposed in aggressive environment in case of poor and/or unfeasible maintenance and inspection during service life. As for thin-walled members, the corrosion hazard can be exacerbated due to the thin thickness of components and the coupled effect between corrosion and buckling can significantly reduce the structural capacity of such structures. Following these considerations, this paper presents a study on the reliability of a thin-walled steel section subjected to the damage induced by atmospheric corrosion in outdoor environments, combining predictive corrosion models for metals with structural reliability applications. A general procedure for the evaluation of the time variant capacity is proposed and discussed in detail. Finally, an application to a C-lipped cold formed section is presented and a reliability analysis of the deteriorating section is carried out to evaluate the coupled effect of corrosion and buckling, according to the proposed procedure

Exercise training in patients with chronic heart failure: A new challenge for Cardiac Rehabilitation Community

Exercise training (ET) is strongly recommended in patients with chronic stable heart failure (HF). Moderate-intensity aerobic continuous ET is the best established training modality in HF patients. In the last decade, however, high-intensity interval exercise training (HIIT) has aroused considerable interest in cardiac rehabilitation community. In HF patients, HIIT exerts larger improvements in exercise capacity compared to moderate-continuous ET. Since better functional capacity translates into symptoms relief and improvement in quality of life in patients with HF, this training modality is collecting growing interest and consensus, not revealing major safety issues. HIIT should not replace other training modalities in HF but should rather complement them. Inspiratory muscle training, another promising training modality in patients with HF, exerts beneficial effect on inspiratory muscle strength and inspiratory endurance, on exercise capacity and quality of life. In conclusion, taking into consideration the complecity of HF syndrome, combining and tailoring different ET modalities according to each patient's baseline clinical characteristics (i.e. exercise capacity, comorbidity, frailty status, personal needs, preferences and goals) seem the most wily approach for exercise prescription

Diabetes mellitus and ischemic heart disease. the role of ion channels

Diabetes mellitus is one the strongest risk factors for cardiovascular disease and, in particular, for ischemic heart disease (IHD). The pathophysiology of myocardial ischemia in diabetic patients is complex and not fully understood: some diabetic patients have mainly coronary stenosis obstructing blood flow to the myocardium; others present with coronary microvascular disease with an absence of plaques in the epicardial vessels. Ion channels acting in the cross-talk between the myocardial energy state and coronary blood flow may play a role in the pathophysiology of IHD in diabetic patients. In particular, some genetic variants for ATP-dependent potassium channels seem to be involved in the determinism of IH

The prediction of collapse mechanisms for masonry structures affected by ground movements using Rigid Block Limit Analysis

Abstract Masonry structures belonged to the Cultural Heritage suffered severe damages in the last decays due to the action of the settlement-induced ground movements. The researchers have been developing numerical tools for the vulnerability analysis and assessment of masonry structures subjected to settlements. Continuous, discrete and rigid block models were proposed in literature. The analysis of both local or global failure modes due to settlement is a still debated topic, involving several questions related to the modelling techniques and to the investigation of the parameters which affect the masonry behaviour against foundation movements. In this framework, the paper focuses on a numerical approach for the settlement analysis based on the rigid block limit analysis. The Italian Code (NTC 2018) also suggests linear kinematic approach for the seismic-induced collapse mechanisms analysis. In such a formulation, the structure is modelled as a collection of polyhedral rigid blocks assuming frictional contact interfaces with infinite compressive strength and zero tensile strength and neglecting the mortar contribution. Originally formulated for the in-plane and out-of-plane mechanisms analysis, the numerical formulation was recently improved in order to analyze blocky-structures subjected to uniform settlement. Numerical case study of a monumental masonry church facade subjected to uniform settlement at the base was presented in this paper aiming at testing the numerical procedure. The results were discussed to evaluate the software capability and accuracy in the settlement-induced collapse mechanisms prediction

Experimental and Numerical Analysis of Seismic Response of Unreinforced Masonry Cross Vaults

The present paper shows an experimental and numerical analysis to understand the seismic behaviour of unreinforced masonry cross vault. The experimental tests were performed on a 1:5 scale model of a cross vault made of 3D-printed blocks with dry joints. The seismic actions was experimentally simulated as a horizontal force proportional to the vault\u2019s mass by using a quasi-static tilt testing setup. The vault 3D collapse mechanism and its strength expressed in terms of collapse multiplier was investigated, also considering the direction of the seismic action with respect to the vault\u2019s base. The tests results were compared to those obtained from a numerical analysis using a rigid-block model based on 3D limit analysis. The model formulation allows to take into account both associative and non-associative behaviour. A sensitivity analysis on friction angle variation was also investigated to evaluate the accuracy and robustness of the model

Fast Neural Network Inference on FPGAs for Triggering on Long-Lived Particles at Colliders

Experimental particle physics demands a sophisticated trigger and acquisition system capable to efficiently retain the collisions of interest for further investigation. Heterogeneous computing with the employment of FPGA cards may emerge as a trending technology for the triggering strategy of the upcoming high-luminosity program of the Large Hadron Collider at CERN. In this context, we present two machine-learning algorithms for selecting events where neutral long-lived particles decay within the detector volume studying their accuracy and inference time when accelerated on commercially available Xilinx FPGA accelerator cards. The inference time is also confronted with a CPU- and GPU-based hardware setup. The proposed new algorithms are proven efficient for the considered benchmark physics scenario and their accuracy is found to not degrade when accelerated on the FPGA cards. The results indicate that all tested architectures fit within the latency requirements of a second-level trigger farm and that exploiting accelerator technologies for real-time processing of particle-physics collisions is a promising research field that deserves additional investigations, in particular with machine-learning models with a large number of trainable parameters.Comment: 12 pages, 9 figures, 2 table

Microplastics, a Global Issue: Human Exposure through Environmental and Dietary Sources

: Plastic production has grown dramatically over the years. Microplastics (MPs) are formed from the fragmentation of larger plastic debris by combining chemical, physical, and biological processes and can degrade further to form nanoplastics (NPs). Because of their size, MPs and NPs are bioavailable to many organisms and can reach humans through transport along the food chain. In addition to the risk from ingesting MPs themselves, there are risks associated with the substances they carry, such as pesticides, pathogenic microorganisms, and heavy metals, and with the additives added to plastics to improve their characteristics. In addition, bioaccumulation and biomagnification can cause a cumulative exposure effect for organisms at the top of the food chain and humans. Despite the growing scientific interest in this emerging contaminant, the potential adverse effects remain unclear. The aim of this review is to summarize the characteristics (size, shape, color, and properties) of MPs in the environment, the primary sources, and the transport pathways in various environmental compartments, and to shed more light on the ecological impact of MPs and the potential health effects on organisms and humans by identifying human exposure pathways

Does the continuation of low-dose acetylsalicylic acid during the perioperative period of thyroidectomy increase the risk of cervical haematoma? A 1-year experience of two Italian centers

Background: A growing number of patients taking antiplatelet drugs, mainly low-dose acetylsalicylic acid (ASA) (75–150 mg/day), for primary or secondary prevention of thrombotic events, are encountered in every field of surgery. While the bleeding risk due to the continuation of these medications during the perioperative period has been adequately investigated in several surgical specialties, in thyroid surgery it still needs to be clarified. The main aim of this study was to assess the occurrence of cervical haematoma in patients receiving low-dose acetylsalicylic acid, specifically ASA 100 mg/day, during the perioperative period of thyroidectomy. Methods: Patients undergoing thyroidectomy in two high-volume thyroid surgery centers in Italy, between January 2021 and December 2021, were retrospectively analysed. Enrolled patients were divided into two groups: those not taking ASA were included in Group A, while those receiving this drug in Group B. Univariate analysis was performed to compare these two groups. Moreover, multivariate analysis was employed to evaluate the use of low-dose ASA as independent risk factor for cervical haematoma. Results: A total of 412 patients underwent thyroidectomy during the study period. Among them, 29 (7.04%) were taking ASA. Based on the inclusion criteria, 351 patients were enrolled: 322 were included in Group A and 29 in Group B. In Group A, there were 4 (1.24%) cervical haematomas not requiring surgical revision of haemostasis and 4 (1.24%) cervical haematomas requiring surgical revision of haemostasis. In Group B, there was 1 (3.45%) cervical haematoma requiring surgical revision of haemostasis. At univariate analysis, no statistically significant difference was found between the two groups in terms of occurrence of cervical haematoma, nor of the other early complications of thyroidectomy. At multivariate analysis, the use of low-dose ASA did not prove to be an independent risk factor for cervical haematoma. Conclusions: Based on our findings, we believe that in patients receiving this drug, either for primary or secondary prevention of thrombotic events, its discontinuation during the perioperative period of thyroidectomy is not necessary