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This thesis develops an early warning system framework for assessing systemic risks and for predicting systemic events, i.e. periods of extreme financial instability with potential real costs, over the short horizon of six quarters and the long horizon of twelve quarters on the panel of 14 countries both advanced and developing. Firstly, Financial Stress Index is built aggregating indicators from equity, foreign exchange, security and money markets in order to identify starting dates of systemic financial crises for each country in the panel. Secondly, the selection of early warning indicators for assessment and prediction of systemic risks is undertaken in a two- step approach; relevant prediction horizons for each indicator are found by means of a univariate logit model followed by the application of Bayesian model averaging method to identify the most useful indicators. Next, logit models containing useful indicators only are estimated on the panel while their in-sample and out-of-sample performance is assessed by a variety of measures. Finally, having applied the constructed EWS for both horizons to the Czech Republic it was found that even though models for both horizons perform very well in-sample, i.e. both predict 100% of crises, only the long model attains the maximum utility of 0,5 as...

<p>This dissertation explores the potential contributions of the mechanisms for early warning and intelligence sharing to regional security in Africa. The Continental Early Warning System (CEWS) and the Committee on Intelligence and Security Services of Africa (CISSA) are centrally concerned with the dissemination of information to enable decision-making on continental security. The main focus of the dissertation is on the manner in which the information generated by the CEWS and CISSA can contribute to regional security. In order to analyse the potential contribution of the CEWS and CISSA to regional security, a sound theoretical framework is proposed so as to explore how and why states choose to cooperate, as well as addressing multifaceted cooperation and integration at inter-state, government department and nonstate levels. Constructivist interpretations of international cooperation are utilised to explore the role of ideas, meanings and understandings in shaping behaviour. The focus is placed on the manner in which interaction as provided for by the CEWS and CISSA can shape understandings of reality and potentially impact on the definition of actors&rsquo / interests. This is based on the assumption drawn from security community and epistemic community theory that, enabling the creation of shared meanings and shared knowledge there is the potential for both the CEWS and CISSA to have a positive influence on the choices that stakeholders take in favour of peaceful change.</p>

<p>This dissertation explores the potential contributions of the mechanisms for early warning and intelligence sharing to regional security in Africa. The Continental Early Warning System (CEWS) and the Committee on Intelligence and Security Services of Africa (CISSA) are centrally concerned with the dissemination of information to enable decision-making on continental security. The main focus of the dissertation is on the manner in which the information generated by the CEWS and CISSA can contribute to regional security. In order to analyse the potential contribution of the CEWS and CISSA to regional security, a sound theoretical framework is proposed so as to explore how and why states choose to cooperate, as well as addressing multifaceted cooperation and integration at inter-state, government department and nonstate levels. Constructivist interpretations of international cooperation are utilised to explore the role of ideas, meanings and understandings in shaping behaviour. The focus is placed on the manner in which interaction as provided for by the CEWS and CISSA can shape understandings of reality and potentially impact on the definition of actors&rsquo / interests. This is based on the assumption drawn from security community and epistemic community theory that, enabling the creation of shared meanings and shared knowledge there is the potential for both the CEWS and CISSA to have a positive influence on the choices that stakeholders take in favour of peaceful change.</p>

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Intrusion Detection Systems (IDS) are designed to monitor the computer network infrastructure against possible attacks by generating security alerts. With the increase of components connected to computer networks, traditional IDS are not capable of effectively detecting malicious attacks. This occurs either by the distributed amount of data that traverses the network or the complexity of the attacks launched against the network. Therefore, the design of Internet Early Warning Systems (IEWS) enables the early detection of threats in the network, possibly avoiding eventual damages to the network resources. The IEWS works as a sink that collects alerts from different sources (for example, from different IDS), centralizing and correlating information in order to provide a holistic view of the network. This way, the current dissertation describes an IEWS architecture for correlating alerts from (geographically) spread out IDS using the Case-Based Reasoning (CBR) technique together with IP Georeferencing. The results obtained during experiments, which were executed over the implementation of the developed technique, showed the viability of the technique in reducing false-positives. This demonstrates the applicability of the proposal as the basis for developing advanced techniques inside the extended IEWS architecture. / Sistemas de Detecção de Instrução (Intrusion Detection Systems IDS) são projetados para monitorar possíveis ataques à infraestruturas da rede através da geração de alertas. Com a crescente quantidade de componentes conectados na rede, os IDS tradicionais não estão sendo suficientes para a efetiva detecção de ataques maliciosos, tanto pelo volume de dados como pela crescente complexidade de novos ataques. Nesse sentido, a construção de uma arquitetura Internet Early Warning Systems (IEWS) possibilita detectar precocemente as ameaças, antes de causar algum perigo para os recursos da rede. O IEWS funciona como um coletor de diferentes geradores de alertas, possivelmente IDS, centralizando e correlacionado informações afim de gerar uma visão holística da rede. Sendo assim, o trabalho tem como objetivo descrever uma arquitetura IEWS para a correlação de alertas gerados por IDS dispersos geograficamente utilizando a técnica Case-Based Reasoning (CBR) em conjunto com Georreferenciamento de endereços IP. Os resultados obtidos nos experimentos, realizados sobre a implementação da técnica desenvolvida, mostraram a viabilidade da técnica na redução de alertas classificados como falsos-positivos. Isso demonstra a aplicabilidade da proposta como base para o desenvolvimento de técnicas mais apuradas de detecção dentro da arquitetura de IEWS estendida.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The popularization of the Internet has provided an increase in the number of web applications that work with critical information. Parallel to this, attacks that exploit the vulnerabilities of these applications has also grown. This scenario has stimulated companies to invest in tools to monitor their network infrastructure in order to detect malicious activity. One of the main tools used by companies to monitor their network infrastructures and identifying attacks are Intrusion Detection Systems. However, due to expansion of the volume of data in computer networks, these systems are becoming limited. In contrast, researchers have explored the construction of Internet Early Warning Systems to monitor malicious activities on the Internet. This work proposes a data model of a knowledge base for Internet EarlyWarning Systems. The model represents the data of different aspects of the network with a focus on events related to intrusion detection, such as data of alerts generated by intrusion detection systems, information on response measures, traffic statistics and signatures of known attacks. A case study on a real network infrastructure demonstrates the applicability of the data model of knowledge base and identifies the advantages of its use. Furthermore, the data stored in the knowledge base potentializes the construction of situational awareness of monitored environment, directing the activities of the security team and helping in the decision process responses to potential attacks. / A popularização da Internet tem proporcionado um aumento no número de aplicações web que trabalham com informações críticas. Em paralelo a isso, os ataques que exploram as vulnerabilidades dessas aplicações também tem crescido. Esse cenário tem estimulado as empresas a investir em ferramentas para monitorar sua infraestrutura de rede, visando a detecção de atividades mal-intencionadas. Uma das principais ferramentas utilizadas pelas empresas para o monitoramento de suas infraestruturas de redes e identificação de ataques são os Sistemas de Detecção de Intrusão. No entanto, devido a expansão do volume de dados que trafegam nas redes de computadores, estes sistemas estão tornando-se limitados. Em contrapartida, pesquisadores têm explorado a construção de Internet Early Warning Systems para o monitoramento de atividades maliciosas na Internet. Este trabalho propõe a modelagem de dados de uma base de conhecimento para Internet Early Warning Systems. O modelo representa os dados de diferentes aspectos da rede com foco em eventos relacionados a detecção de intrusão, tais como: dados de alertas gerados por sistemas de detecção de intrusão, informações sobre medidas de respostas, estatísticas do tráfego e assinaturas de ataques já conhecidos. Um estudo de caso em uma infraestrutura de rede real demonstra a aplicabilidade do modelo de dados da base de conhecimento e permite identificar as vantagens de sua utilização. Além disso, os dados armazenados na base de conhecimento potencializam a construção de uma consciência situacional do ambiente monitorado, direcionando as atividades da equipe de segurança e auxiliando no processo de decisão de respostas a ataques em potencial.

Magister Artium - MA / This dissertation explores the potential contributions of the mechanisms for early warning and intelligence sharing to regional security in Africa. The Continental Early Warning System (CEWS) and the Committee on Intelligence and Security Services of Africa (CISSA) are centrally concerned with the dissemination of information to enable decision-making on continental security. The main focus of the dissertation is on the manner in which the information generated by the CEWS and CISSA can contribute to regional security. In order to analyse the potential contribution of the CEWS and CISSA to regional security, a sound theoretical framework is proposed so as to explore how and why states choose to cooperate, as well as addressing multifaceted cooperation and integration at inter-state, government department and nonstate levels. Constructivist interpretations of international cooperation are utilised to explore the role of ideas, meanings and understandings in shaping behaviour. The focus is placed on the manner in which interaction as provided for by the CEWS and CISSA can shape understandings of reality and potentially impact on the definition of actors' interests. This is based on the assumption drawn from security community and epistemic community theory that, enabling the creation of shared meanings and shared knowledge there is the potential for both the CEWS and CISSA to have a positive influence on the choices that stakeholders take in favour of peaceful change. / South Africa

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