736 resultados para Security.


Relevância:

20.00% 20.00%

Publicador:

Resumo:

We present two physical layer secure transmission schemes for multi-user multi-relay networks, where the communication from M users to the base station is assisted by direct links and by N decode-and-forward relays. In this network, we consider that a passive eavesdropper exists to overhear the transmitted information, which entails exploiting the advantages of both direct and relay links for physical layer security enhancement. To fulfill this requirement, we investigate two criteria for user and relay selection and examine the achievable secrecy performance. Criterion I performs a joint user and relay selection, while Criterion II performs separate user and relay selections, with a lower implementation complexity. We derive a tight lower bound on the secrecy outage probability for Criterion I and an accurate analytical expression for the secrecy outage probability for Criterion II. We further derive the asymptotic secrecy outage probabilities at high transmit signal-to-noise ratios and high main-to-eavesdropper ratios for both criteria. We demonstrate that the secrecy diversity order is min (MN, M + N) for Criterion I, and N for Criterion II. Finally, we present numerical and simulation results to validate the proposed analysis, and show the occurrence condition of the secrecy outage probability floor

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Although security plays an important role in the development of multiagent systems, a careful analysis of software development processes shows that the definition of security requirements is, usually, considered after the design of the system. One of the reasons is the fact that agent oriented software engineering methodologies have not integrated security concerns throughout their developing stages. The integration of security concerns during the whole range of the development stages can help towards the development of more secure multiagent systems. In this paper we introduce extensions to the Tropos methodology to enable it to model security concerns throughout the whole development process. A description of the new concepts and modelling activities is given along with a discussion on how these concepts and modelling activities are integrated to the current stages of Tropos. A real life case study from the health and social care sector is used to illustrate the approach.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

More and more software projects today are security-related in one way or the other. Requirements engineers often fail to recognise indicators for security problems which is a major source of security problems in practice. Identifying security-relevant requirements is labour-intensive and errorprone. In order to facilitate the security requirements elicitation process, we present an approach supporting organisational learning on security requirements by establishing company-wide experience resources, and a socio-technical network to benefit from them. The approach is based on modelling the flow of requirements and related experiences. Based on those models, we enable people to exchange experiences about security-requirements while they write and discuss project requirements. At the same time, the approach enables participating stakeholders to learn while they write requirements. This can increase security awareness and facilitate learning on both individual and organisational levels. As a basis for our approach, we introduce heuristic assistant tools which support reuse of existing security-related experiences. In particular, they include Bayesian classifiers which issue a warning automatically when new requirements seem to be security-relevant. Our results indicate that this is feasible, in particular if the classifier is trained with domain specific data and documents from previous projects. We show how the ability to identify security-relevant requirements can be improved using this approach. We illustrate our approach by providing a step-by-step example of how we improved the security requirements engineering process at the European Telecommunications Standards Institute (ETSI) and report on experiences made in this application.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Building secure systems is difficult for many reasons. This paper deals with two of the main challenges: (i) the lack of security expertise in development teams, and (ii) the inadequacy of existing methodologies to support developers who are not security experts. The security standard ISO 14508 (Common Criteria) together with secure design techniques such as UMLsec can provide the security expertise, knowledge, and guidelines that are needed. However, security expertise and guidelines are not stated explicitly in the Common Criteria. They are rather phrased in security domain terminology and difficult to understand for developers. This means that some general security and secure design expertise are required to fully take advantage of the Common Criteria and UMLsec. In addition, there is the problem of tracing security requirements and objectives into solution design,which is needed for proof of requirements fulfilment. This paper describes a security requirements engineering methodology called SecReq. SecReq combines three techniques: the Common Criteria, the heuristic requirements editorHeRA, andUMLsec. SecReqmakes systematic use of the security engineering knowledge contained in the Common Criteria and UMLsec, as well as security-related heuristics in the HeRA tool. The integrated SecReq method supports early detection of security-related issues (HeRA), their systematic refinement guided by the Common Criteria, and the ability to trace security requirements into UML design models. A feedback loop helps reusing experiencewithin SecReq and turns the approach into an iterative process for the secure system life-cycle, also in the presence of system evolution.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper investigates the paradoxes inherent in Thai and Vietnamese drug policies. The two countries have much in common. Both are ultra-prohibitionist states which employ repressive policies to contain drug markets. Their policies have, however, diverged in two key areas: opium suppression and harm reduction. Thailand implemented an effective intervention to suppress opium farming centred upon alternative development, whereas Vietnam suppressed opium production through coercive negotiation with nominal alternative development. Vietnam has embraced elements of harm reduction, whereas Thailand has been slow to implement harm reduction policies. This paper hypothesises that these two differences are largely a product of their perceived relationship to security. The two cases demonstrate how once an issue is securitized the ultra-prohibitionist rules of the game can be broken to allow for more humane and pragmatic policies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

As the number of pensioners in Europe rises relative to the number of people in employment, the gap between the contributions and the benefit levels increases, and consequently ensuring adequate pensions on a sustainable basis has become a major challenge. This study aims to explore the potential of using the Data Envelopment Analysis (DEA) technique in order to access the efficiency of the income protection in old age, one of the most important branches of Social Security. To this effect, we collected data from the 27 European Union Member States regarding this branch. Our results show important differences among the Member States and stress the importance of identifying best practices to achieve more adequate, sustainable and modernised pension systems. Our results also highlight the importance of using DEA as a decision support tool for policy makers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Spending on security in an SME usually has to compete with demands for hardware, infrastructure, and strategic applications. In this paper, the authors seek to explore the reasons why smaller SMEs in particular have consistently failed to see securing information as strategic year-on-year spending, and just regard as part of an overall tight IT budget. The authors scrutinise the typical SMEs reasoning for choosing to see non-spending on security as an acceptable strategic risk. They look particularly at possible reasons why SMEs tend not to take much notice of "scare stories" in the media based on research showing they are increasingly at risk, whilst larger businesses are taking greater precautions and become more difficult to penetrate. The results and their analysis provide useful pointers towards broader business environment changes that would cause SMEs to be more risk-averse and ethical in their approach to securing their own and their clients’ information.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper explores the prospects and challenges of achieving human security through United Nations (UN) human rights law. The paper does not aim to pronounce definitively on the achievement of human security by way of UN human rights law that is, to assess the achievement of human security per se 'as a future end state'. Rather the focus of the paper is firmly placed on the capacity of UN human rights law to achieve human security. The paper departs from the premise that if human rights define human security, international human rights law and UN human rights law in particular should have something to say about the achievement of human security.