ICMP-based Third-Party Estimation of Cloud Availability

Cloud availability is an important parameter present in a typical Service Level Agreement (SLA). In order to check compliance with SLA commitments, a third party availability measurement is strongly needed. An availability estimation methods is evaluated here, based on the periodic repetition of sequence of probing packets in ICMP. Majority Voting, which declares a cloud to be available only if a majority of probing packets gets an echo from the cloud, appears to provide an accurate estimation even when the packet loss probability is rather high

European H2020 Project WORTECS Wireless Mixed Reality Prototyping

This paper presents European collaborative project WORTECS objectives and reports on the development of several radio and optical wireless prototypes and a demonstrator targeting mixed reality (MR) application. The aim is to achieve a net throughput of up to Tbps in an indoor heterogeneous network for the MR use case, which seems to be a high throughput "killer application" beyond 5G. A special routing device is associated with the demonstrator to select the most suitable wireless access technology. Post introduction to the project, an overview of the demonstrator is presented with details of the current progress of the prototypes

Combined control and data plane robustness of SDN networks against malicious node attacks

In the context of software-defined networking (SDN), we address a variant of the controller placement problem (CPP), which takes into account the network robustness at both control and data plane layers. For given maximum values of switch-controller and controller-controller delays at the regular state (i.e., when the network is fully operational), the aim is to maximize the network robustness against a set of failure states, each state defined as a possible malicious attack to multiple network nodes. We assume that the attacker knows the data plane topology and, therefore, can adopt either one of three commonly considered node centrality attacks (based on the node degree, closeness or betweenness centralities), or an attack to the nodes which are the optimal solution of the critical node detection (CND) problem. We propose a set of robustness metrics which are used to obtain the optimal solutions for the robust CPP variant. We present a set of computational results comparing the average delays and robustness values of the robust CPP solutions against those minimizing only the average switch-controller and controller-controller delays. Moreover, the impact of using the CND based attack in the robustness evaluation of CPP solutions is also assessed in the computational results.publishe

Contributos para a estratégia das políticas culturais da região Norte de Portugal até 2030

Establishing strategies for public cultural policies in Portugal is not yet an anchored practice. In this article we call on the results of a multidimensional study, which was carried out in 2020 for the Regional Directorate for Culture of the North (Portugal), with the goal of gathering contributions to devise a strategy for regional cultural policies until 2030.A definição de estratégias para as políticas culturais públicas em Portugal ainda não é uma prática ancorada. No presente artigo vamos convocar os resultados de um estudo multidimensional, que foi realizado, no ano de 2020 para Direção Regional de Cultura do Norte (Portugal), com o objetivo de reunir contributos para a definição de uma estratégia para as políticas culturais regionais até 2030

A digital-based integrated methodology for the preventive conservation of cultural heritage: the experience of HeritageCare project

A sustainable conservation strategy for cultural heritage protection is not feasible without a systematic documentation, registration and management of the information. The adoption of integrated inspection protocols and regular tracking processes, based on standardized procedures and uniform criteria, are the basis to successfully replace actual curative strategies with proactive conservation approaches. The opportunities brought by the digital tools can offer tremendous advantages in this regard. This paper explores the leading role that digitization is assuming in the context of heritage conservation through the experience of the HeritageCare project - Monitoring and preventive conservation of historic and cultural heritage" (SOE1/P5/P0258). The project has developed a digital-based integrated methodology aimed at providing enhanced tools and services to properly document cultural heritage buildings and engage directly owners in the conservation process of their legacy. The structured digital workflow on which the HeritageCare protocol relies is described in detail, encompassing different levels of information. Finally, the full application of the protocol is presented with reference to one of the most emblematic case studies of the project, the Ducal Palace of Guimaraes, Portugal.- This work was partly financed by FEDER funds through the Competitiveness Factors Operational Programme (COMPETE) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project POCI-01-0145-FEDER-007633

An Analytical Model for Wireless Mesh Networks with Collision-Free TDMA and Finite Queues

Wireless mesh networks are a promising technology for connecting sensors and actuators with high flexibility and low investment costs. In industrial applications, however, reliability is essential. Therefore, two time-slotted medium access methods, DSME and TSCH, were added to the IEEE 802.15.4 standard. They allow collision-free communication in multi-hop networks and provide channel hopping for mitigating external interferences. The slot schedule used in these networks is of high importance for the network performance. This paper supports the development of efficient schedules by providing an analytical model for the assessment of such schedules, focused on TSCH. A Markov chain model for the finite queue on every node is introduced that takes the slot distribution into account. The models of all nodes are interconnected to calculate network metrics such as packet delivery ratio, end-to-end delay and throughput. An evaluation compares the model with a simulation of the Orchestra schedule. The model is applied to Orchestra as well as to two simple distributed scheduling algorithms to demonstrate the importance of traffic-awareness for achieving high throughput.Comment: 17 pages, 14 figure

Disaster-resilient communication networks:Principles and best practices

Communication network failures that are caused by disasters, such as hurricanes, earthquakes and cyber-attacks, can have significant economic and societal impact. To address this problem, the research community has been investigating approaches to network resilience for several years. However, aside from well-established techniques, many of these solutions have not found their way into operational environments. The RECODIS COST Action aims to address this shortcoming by providing solutions that are tailored to specific types of challenge, whilst considering the wider socio-economic issues that are associated with their deployment. To support this goal, in this paper, we present an overview of some of the foundational related work on network resilience, covering topics such as measuring resilience and resilient network architectures, amongst others. In addition, we provide insights into current operational best practices for ensuring the resilience of carrier-grade communication networks. The aim of this paper is to support the goals of the EU COST Action RECODIS and the wider research community in engineering more resilient communication networks