Intrusion Tolerance: Concepts and Design Principles. A Tutorial

In traditional dependability, fault tolerance has been the workhorse of the many solutions published over the years. Classical security-related work has on the other hand privileged, with few exceptions, intrusion prevention, or intrusion detection without systematic forms of processing the intrusion symptoms. A new approach has slowly emerged during the past decade, and gained impressive momentum recently: intrusion tolerance. The purpose of this tutorial is to explain the underlying concepts and design principles. The tutorial reviews previous results under the light of intrusion tolerance (IT), introduces the fundamental ideas behind IT, and presents recent advances of the state-of-the-art, coming from European and US research efforts devoted to IT. The program of the tutorial will address: a review of the dependability and security background; introduction of the fundamental concepts of intrusion tolerance (IT); intrusion-aware fault models; intrusion prevention; intrusion detection; IT strategies and mechanisms; design methodologies for IT systems; examples of IT systems and protocol

Capital Social e Políticas Públicas: Análise da implementação do Programa de Luta Contra a Pobreza no Meio Rural nos municípios de São Miguel e Tarrafal

Este trabalho foi desenvolvido no quadro da realização do Mestrado em Ciências Sociais pela Universidade de Cabo Verde. Tem como objectivo analisar as possibilidades e os limites de concretização da estratégia de redução da pobreza adoptada pelo Programa de Luta Contra a Pobreza no Meio Rural que considera o capital social como recurso para o desenvolvimento das comunidades. Em específico, procura analisar como essa estratégia é apropriada e implementada pelas associações comunitárias de desenvolvimento e o impacto das actividades desenvolvidas por essas associações no capital social e na redução da pobreza nos municípios de São Miguel e Tarrafal na ilha de Santiago. A recolha de dados foi feita, basicamente, junto de líderes de associações comunitárias de desenvolvimento e de chefes de agregados familiares, com base num guião de entrevista e num questionário previamente elaborados. Em termos teóricos, a concepção de capital social formulada por Robert Putnam constitui o eixo analítico do presente trabalho. Os dados recolhidos apontam que para além dos inquiridos não assumirem a ideia de comunidade preconizada pelo Programa de Luta Contra a Pobreza no Meio Rural, que as actividades desenvolvidas pelas associações comunitárias de desenvolvimento não contribuíram para um reforço significativo do capital social das comunidades abrangidas pelo estudo, não obstante reconhecerem que essas actividades tiveram um impacto positivo na redução da pobreza

Timing Failure Detection with a Timely Computing Base

In a recent report we proposed an architectural construct to address the problem of dealing with timeliness specifications in a generic way. We called it the Timely Computing Base, TCB. The TCB defines a set of services available to applications, including timely execution, duration measurement and timing failure detection. We showed how these services could be used to build dependable and timely applications. In this paper we further extend the description of the TCB, namely by presenting a protocol for its Timing Failure Detection (TFD) service. We discuss the essential aspects of providing such a service under the TCB framework and make some considerations relative to the service interfac

Property Law in Roman Egypt in the Light of the Papyri: Safeguarding Women's Economic Interests

This study looks at the role of women in the economic environment of Roman Egypt in the light of the papyri. By examining marriage and inheritance documents from the first three centuries, the study shows that marital and inheritance laws and customs in Roman Egypt were made to protect women’s interests when it came to ownership and possession of property, which is one of the main reasons why women played such a prominent role in Egypt’s economic environment

Efeitos da protensão na frequência natural de vigas de concreto

The development of researches related to Structural Dynamics is no longer motivated just to understand the behavior of buildings in relation to seismic actions. This fact happened because there was an advance of materials and technologies used in the constructions, which allowed the construction of larger, more complex and slender edifications, that consequently needs a better knowledge of their structural functioning. To solve this requisite, the study of Structural Dynamics is a very useful and precise tool. Still, in the context of Civil Engineering modernization, the prestressing technique on structures has become an effective and useful technology to provide structural solutions, because it offers a good cost-benefit ratio. For these structures to function as expected and do not present pathologies, it is necessary to study their dynamic characteristics. This paper presents a study about the effects that the prestress force can cause in a concrete beam, mainly on natural vibration frequency. For this, it was carried out an analytical and experimental comparative study of a beam model. This comparison shows the analytical method produces consistent results with that observed experimentally, provided that is possible to quantify the stifness of structure. It was also noted that the prestress force wasn’t sufficient to increase the stiffness of the element and consequently did not alter their natural frequency. In addition, the influence of the prestress technique as structural reinforcement was analyzed.O desenvolvimento das pesquisas relacionadas à dinâmica das estruturas deixou de ser motivado apenas pela necessidade de entender o comportamento das construções em relação às ações sísmicas. Isso ocorre devido ao avanço dos materiais e das tecnologias utilizadas nas obras, possibilitando a construção de edificações maiores, mais complexas e esbeltas, que consequentemente precisam de uma maior análise no seu funcionamento estrutural. Para atender essa necessidade, o estudo da dinâmica das estruturas é uma ferramenta bastante útil e precisa. Ainda no contexto de modernização da construção, a técnica de protensão de estruturas se tornou uma tecnologia eficaz e bastante utilizada para proporcionar soluções estruturais ousadas, pois oferece uma boa relação custo-benefício nesses casos. Para que essas estruturas funcionem da forma esperada e não apresentem patologias, é necessário que suas características dinâmicas sejam estudadas. O presente trabalho apresenta um estudo sobre os efeitos que a protensão pode causar em uma viga de concreto, principalmente no que diz respeito à sua frequência de vibração natural. Para isso, foi realizado o estudo comparativo de modelos analíticos e experimentais de uma viga. O resultado dessa comparação foi que o método analítico produz resultados coerentes com o observado experimentalmente, desde que seja possível quantificar precisamente a rigidez da estrutura. Ainda, foi notado que a carga de protensão aplicada não foi suficiente para aumentar a rigidez do elemento e consequentemente não alterou a sua frequência natural. Além disso, foi analisada a influência da protensão como reforço estrutural

Preliminary Specification of Services and Protocols

This document describes the preliminary specification of services and protocols for the Crutial Architecture. The Crutial Architecture definition, first addressed in Crutial Project Technical Report D4 (January 2007), intends to reply to a grand challenge of computer science and control engineering: how to achieve resilience of critical information infrastructures, in particular in the electrical sector. The definitions herein elaborate on the major architectural options and components established in the Preliminary Architecture Specification (D4), with special relevance to the Crutial middleware building blocks, and are based on the fault, synchrony and topological models defined in the same document. The document, in general lines, describes the Runtime Support Services and APIs, and the Middleware Services and APIs. Then, it delves into the protocols, describing: Runtime Support Protocols, and Middleware Services Protocols. The Runtime Support Services and APIs chapter features as a main component, the Proactive-Reactive Recovery Service, whose aim is to guarantee perpetual execution of any components it protects. The Middleware Services and APIs chapter describes our approach to intrusion-tolerant middleware. The middleware comprises several layers. The Multipoint Network layer is the lowest layer of CRUTIAL's middleware, and features an abstraction of basic communication services, such as provided by standard protocols, like IP, IPsec, UDP, TCP and SSL/TLS. The Communication Support Services feature two important building blocks: the Randomized Intrusion-Tolerant Services (RITAS), and the Overlay Protection Layer (OPL) against DoS attacks. The Activity Support Services currently defined comprise the CIS Protection service, and the Access Control and Authorization service. Protection as described in this report is implemented by mechanisms and protocols residing on a device called Crutial Information Switch (CIS). The Access Control and Authorization service is implemented through PolyOrBAC, which defines the rules for information exchange and collaboration between sub-modules of the architecture, corresponding in fact to different facilities of the CII's organizations.The Monitoring and Failure Detection layer contains a preliminary definition of the middleware services devoted to monitoring and failure detection activities. The remaining chapters describe the protocols implementing the above-mentioned services: Runtime Support Protocols, and Middleware Services Protocol

Avaliação da implementação de Medidas de Preservação Auditiva numa indústria têxtil – modelo a seguir

O ruído é um tipo de som que provoca efeitos nocivos no ser humano, sendo uma sensação auditiva desagradável que interfere na percepção do som desejado. Define-se, do ponto de vista físico, como toda a vibração mecânica estatisticamente aleatória de um meio elástico e, do ponto de vista fisiológico, como todo o fenómeno acústico que produz uma sensação auditiva desagradável ou incomodativa (Reis, 2002; Boger, 2008)

On the Resilience of Intrusion-Tolerant Distributed Systems

The paper starts by introducing a new dimension along which distributed systems resilience may be evaluated - exhaustion-safety. A node-exhaustion-safe intrusion-tolerant distributed system is a system that assuredly does not suffer more than the assumed number of node failures (e.g., crash, Byzantine). We show that it is not possible to build this kind of systems under the asynchronous model. This result follows from the fact that in an asynchronous environment one cannot guarantee that the system terminates its execution before the occurrence of more than the assumed number of faults. After introducing exhaustion-safety, the paper proposes a new paradigm - proactive resilience - to build intrusion-tolerant distributed systems. Proactive resilience is based on architectural hybridization and hybrid distributed system modeling. The Proactive Resilience Model (PRM) is presented and shown to be a way of building node-exhaustion-safe intrusion-tolerant systems. Finally, the paper describes the design of a secret sharing system built according to the PRM. A proof-of-concept prototype of this system is shown to be highly resilient under different attack scenarios

Factores que influenciam a discriminação social em idosos

The aim was to evaluate the perception of the elderly about the occurrence of episodes of social discrimination and to identify factors that influence social discrimination. Descriptive-correlational study, with 333 elderly people. The Social Discrimination Against the Elderly scale was used. Most were female (59.5%), mean age 76.13 years; 83.1% perceive themselves to have been victims of episodes of social discrimination. Activities of daily living (p = 0.000), depression (p = 0.000), total functional social support (p = 0.001), visiting or receiving visits from family or friends (p = 0.005) influence the social discrimination of the elderly . It was found that elderly people who are less independent in activities of daily living, more depressed, with less functional social support and who do not visit or are visited by family or friends tend to be victims of greater social discrimination. The results point to the need for greater attention from the community in general and from health professionals in particular, in order to devise adequate prevention and resolution strategies for this phenomenon.Objetivou-se avaliar a perceção da pessoa idosa acerca da ocorrência de episódios de discriminação social e identificar fatores que influenciam a discriminação social. Estudo descritivo-correlacional, com 333 idosos. Foi utilizada a escala de Discriminação Social Contra as Pessoas Idosas. A maioria era do sexo feminino (59,5%), média de idades 76,13 anos; 83,1% perceciona ter sido vítima de episódios de discriminação social. As atividades de vida diária (p = 0,000), a depressão (p = 0,000), o apoio social funcional total (p = 0,001), visitar ou receber visitas de familiares ou amigos (p = 0,005) influenciam a discriminação social da pessoa idosa. Verificou-se que os idosos menos independentes nas atividades de vida diária, mais deprimidos, com menor apoio social funcional e que não visitam nem são visitados por familiares ou amigos tendem a ser vítimas de maior discriminação social. Os resultados apontam para a necessidade de uma maior atenção da comunidade em geral e dos profissionais de saúde em particular, de forma a traçarem estratégias adequadas de prevenção e de resolução deste fenómeno