ESTGV - DI - Documentos de congressos (comunicações, posters, actas)
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- Assurance and trust indicators to evaluate accuracy of on-line risk in critical infrastructuresPublication . Schaberreiter, Thomas; Caldeira, Filipe; Aubert, Jocelyn; Monteiro, Edmundo; Khadraoui, Djamel; Simoes, PauloCritical infrastructure (CI) services are consumed by the society constantly and we expect them to be available 24 hours a day. A common definition is that CIs are so vital to our society that a disruption or destruction would have a severe impact on the social well-being and the economy on national and international levels. CIs can be mutually dependent on each other and a failure in one infrastructure can cascade to another (inter)dependent infrastructure and cause service disruptions. Methods to better assess and monitor CIs and their (inter)dependencies at run-time in order to be able to evaluate possible risks have to be developed. Furthermore, methods to ensure the validity of evaluated risk have to be investigated. In this work, we build on existing work of CI security modelling, a CI model that allows modelling the risks of CI services at run-time. We conduct a study of indicators allowing to evaluate the correctness of calculated service risk, taking into account various sources contributing to this evaluation. Trust-based indicators are introduced to capture the dynamically changing behaviour of a system.
- Descrição, Geração e Difusão de Políticas de SegurançaPublication . Caldeira, Filipe; Monteiro, EdmundoNeste artigo é apresentada uma ferramenta de descrição de Políticas de Segurança, baseada na linguagem SPSL (Security Policy Specification Language). A ferramenta permite efectuar a descrição de políticas de segurança posteriormente utilizadas na criação e difusão de regras reconhecidas por vários equipamentos na implementação das políticas de segurança das organizações.
- Dynamic enhancement of videogame soundscapesPublication . Pires, Durval; Alves, Valter; Roque, LicinioA game soundscape often includes sounds that are triggered by the game logic according to the player’s actions and to other real time occurrences. The dynamic nature of such triggering events leads to a composition that is not necessarily interesting, at a given moment. We propose a system aiming at the enhancement of the soundscape generated during gameplay. The main component of the system is a module that implements heuristics, which we set to follow principles from Acoustic Ecology and, specifically, the notion of healthy soundscape. In order to inform the heuristics, designers can characterize the sounds being handled by the sound engine, using an API that aims to be accessible and informative about the designer’s intentions. We also present reflections on an essay where a game was remade using the proposed system, which helped us to support the feasibility of the proposed system.
- e-Consultation as a tool for participation in teachers’ unions: the greater the focus, the greater the number of visitsPublication . Quental, Carlos; Gouveia, Luis BorgesIn the 2000’s, the Internet became the preferred mean for the citizens to communicate. The YouTube, Twitter, Facebook, LinkedIn, i.e., the social networks in general appeared together with the Web 2.0, which allows an extraordinary interaction between citizens and the democratic institutions. The trade unions constantly fight governments’ decisions, especially in periods of crisis like the one that the world, Europe and, in particular, Portugal are facing. In this regard, the use of e-participation platforms is expected to strengthen the relationship between trade unions and the education community. This paper reports the research about the planning and driving of a series of experiments of online public consultation, launched by teachers’ trade unions. These experiments are compared with those of other countries, such as Australia, United Kingdom and United States of America. A quantitative analysis of the results regarding hits, subscriptions, and response rates is presented, and it is compared with the 90-9-1 rule, the ASCU model and data from government agencies. The experiments performed used the Liberopinion, an online platform that supports bidirectional asynchronous communication. A better understanding of the benefits of these collaborative environments is expected by promoting quality of interaction between actors.
- Esquema de Multiresolução para Aplicações Geométricas em Tempo RealPublication . Rodrigues, Rui; Morgado, José Francisco; Silva, Frutuoso; Gomes, AbelEste artigo descreve um novo esquema multiresolução que manipula a geometria e topologia duma forma separada. A sua estrutura de dados designa-se por estrutura de dados baseada na aresta fantasma. Este esquema recorre a um critério topológico (não a um critério geométrico, como e ́ usual) para simplificar a malha mais rapidamente, o que deixa em aberto a sua utilização em aplicações em tempo real.
- Gestão por políticas: arquitectura e aplicaçõesPublication . Caldeira, Filipe; Monteiro, EdmundoNeste artigo é feita uma abordagem à gestão de redes baseadas em políticas focando a arquitectura PBN (Policy-Based Networking) proposta no âmbito do grupo de trabalho Policy Framework do IETF (Internet Engineering Task Force). São evidenciados os principais aspectos desta arquitectura, desde os protocolos de comunicação até às linguagens de especificação de políticas, passando pelos modelos necessários à representação de informação. Relativamente às linguagens de especificação de políticas, apresenta-se uma visão geral sobre a sua aplicabilidade na arquitectura PBN. No âmbito dos protocolos de difusão de política, destacase o protocolo COPS (Common Open Policy Service) e COPS-PR (COPS for Policy provisioning). O artigo termina com a descrição de uma aplicação de gestão de firewalls através do uso de políticas. Esta aplicação baseia-se na arquitectura de gestão por políticas (PBN) proposta e aplica a linguagem SPSL e o protocolo COPS-PR.
- Improved Resilience of Interdependent Critical Infrastructures via on-line Alerting SystemPublication . Capodieci, Paolo; Diblasi, Stefano; Ciancamerla, Ester; Minichino, Michele; Foglietta, Chiara; Lefevre, Davide; Oliva, Gabriele; Panzieri, Stefano; Setola, Roberto; De Porcellinis, Stefano; Delli Priscoli, Francesco; Castrucci, Marco; Suraci, Vincenzo; Lev, Leonid; Shneck, Yosi; Khadraoui, Djamel; Aubert, Jocelyn; Iassinovski, Serguei; Jiang, Jianmin; Simoes, Paulo; Caldeira, Filipe; Spronska, Agnieszka; Harpes, Carlo; Aubigny, MatthieuThis paper illustrates the activities under development within the FP7 EU MICIE project. The project is devoted to design and implement an on-line alerting system, able to evaluate, in real time, the level of risk of interdependent Critical Infrastructures (CIs). Such a risk is generated by undesired events and by the high level of interconnection of the different infrastructures. Heterogeneous models are under development to perform short term predictions of the Quality of Service (QoS) of each CI according to the QoS of the others, to the level of interdependency among the Infrastructures, and according to the undesired events identified in the reference scenario.
- Policy Based and Trust Management for Critical Infrastructure ProtectionPublication . Caldeira, Filipe; Monteiro, Edmundo; Simões, PauloCritical infrastructure (CI) services are consumed by the society constantly and we expect them to be available 24 hours a day. A common definition is that CIs are so vital to our society that a disruption or destruction would have a severe impact on the social well-being and the economy on a national and an international level. CIs can be mutually dependent on each other and a failure in one infrastructure can cascade to another interdependent infrastructure to cause service disruptions. Methods to better assess and monitor CIs and their interdependencies in order to predict possible risks have to be developed. This work addresses the problem of the quality of information exchanged among interconnected CI, the quality of the relationship in terms of trust and security and the use of Trust and Reputation management along with the Policy Based Management paradigm is the proposed solution to be applied at the CI interconnection points for information exchange.
- A policy-based approach to firewall managementPublication . Caldeira, Filipe; Monteiro, EdmundoThis paper describes a policy-based approach to firewall management. The Policy-Based Networking (PBN) architecture proposed by the Policy Framework Group of IETF is analysed, together with the communication protocols, policy specification languages, and the necessary information models. The paper continues with a description of an application of the PBN architecture to firewall management. The proposed architecture is presented and its implementation issues are analysed with some usage examples. The paper concludes with the evaluation of the policy-based approach to firewall management.
- Reboot-based Recovery of Performance Anomalies in Adaptive Bitrate Video-Streaming ServicesPublication . Cunha, Carlos Augusto da Silva; Silva, Luis M. ePerformance anomalies represent one common type of failures in Internet servers. Overcoming these failures without introducing server downtimes is of the utmost importance in video-streaming services. These services have large user abandon- ment costs when failures occur after users watch a significant part of a video. Reboot is the most popular and effective technique for overcoming performance anomalies but it takes several minutes from start until the server is warmed-up again to run at its full capacity. During that period, the server is unavailable or provides limited capacity to process end-users’ requests. This paper presents a recovery technique for performance anomalies in HTTP Streaming services, which relies on Container-based Virtualization to implement an efficient multi-phase server reboot technique that minimizes the service downtime. The recovery process includes analysis of variance of request-response times to delimit the server warm-up period, after which the server is running at its full capacity. Experimental results show that the Virtual Container recovery process completes in 72 seconds, which contrasts with the 434 seconds required for full operating system recovery. Both recovery types generate service downtimes imperceptible to end-users.