55 research outputs found
Selecting Security Patterns that Fulfill Security Requirements
Over the last few years a large number of security patterns have been proposed. However, this large number of patterns has created a problem in selecting patterns that are appropriate for different security requirements. In this paper, we present a selection approach for security patterns, which allows us to understand in depth the trade-offs involved in the patterns and the implications of a pattern to various security requirements. Moreover, our approach supports the search for a combination of security patterns that will meet given security requirements
Modelling Secure Systems Using An Agent Oriented Approach and Security Patterns
In this paper we describe an approach for modelling security issues in information systems. It is based on an agent-oriented approach, and extends it with the use of security patterns. Agent-oriented software engineering provides advantages when modeling security issues, since agents are often a natural way of conceptualizing an information system, in particular at the requirements stage, when the viewpoints of multiple stakeholders need to be considered. Our approach uses the Tropos methodology for modelling a system as a set of agents and their social dependencies, with specific extensions for representing security constraints. As an extension to the existing methodology we propose the use of security patterns. These patterns capture proven solutions to common security issues, and support the systematic and structured mapping of these constraints to an architectural model of the system, in particular for non-security specialists
Security Patterns Meet Agent Oriented Software Engineering: A Complementary Solution for Developing Secure Information Systems
Agent Oriented Software Engineering and security patterns have been proposed as suitable paradigms for the development of secure information systems. However, so far, the proposed solutions are focused on one of these paradigms. In this paper we propose an agent oriented security pattern language and we discuss how it can be used together with
the Tropos methodology to develop secure information systems. We also present a formalisation of our pattern language using Formal Tropos. This allows us to gain a deeper understanding of the patterns and their relationships, and thus to assess the completeness of the language
Integrating Patterns and Agent-Oriented Methodologies to Provide Better Solutions for the Development of Secure Agent-Based Systems
Although pattern languages have already been proposed for security modelling, such
languages mostly employ concepts and notations related to object-oriented systems, and have mainly neglected the agent-oriented paradigm. In this position paper we argue about the need to define a security pattern language applicable to agent-based systems that employs concepts based in the agent-oriented paradigm. In addition, we motivate the need to integrate such a language within the development stages of an agent-oriented methodology, and we briefly discuss what such a language should contain
Eating increases oxidative damage in a reptile
While eating has substantial benefits in terms of both nutrient and energy acquisition, there are physiological costs associated with digesting and metabolizing a meal. Frequently, these costs have been documented in the context of energy expenditure while other physiological costs have been relatively unexplored. Here, we tested whether the seemingly innocuous act of eating affects either systemic pro-oxidant (reactive oxygen metabolite, ROM) levels or antioxidant capacity of corn snakes (Pantherophis guttatus) by collecting plasma during absorptive (peak increase in metabolic rate due to digestion of a meal) and non-absorptive (baseline) states. When individuals were digesting a meal, there was a minimal increase in antioxidant capacity relative to baseline (4%), but a substantial increase in ROMs (nearly 155%), even when controlling for circulating nutrient levels. We report an oxidative cost of eating that is much greater than that due to long distance flight or mounting an immune response in other taxa. This result demonstrates the importance of investigating non-energetic costs associated with meal processing, and it begs future work to identify the mechanism(s) driving this increase in ROM levels. Because energetic costs associated with eating are taxonomically widespread, identifying the taxonomic breadth of eating-induced ROM increases may provide insights into the interplay between oxidative damage and life history theory
Security requirements modelling for virtualized 5G small cell networks
It is well acknowledged that one of the key enabling factors for the realization of future 5G networks will be the small cell (SC) technology. Furthermore, recent advances in the fields of network functions virtualization (NFV) and software-defined networking (SDN) open up the possibility of deploying advanced services at the network edge. In the context of mobile/cellular networks this is referred to as mobile edge computing (MEC). Within the scope of the EU-funded research project SESAME we perform a comprehensive security modelling of MEC-assisted quality-of-experience (QoE) enhancement of fast moving users in a virtualized SC wireless network, and demonstrate it through a representative scenario toward 5G. Our modelling and analysis is based on a formal security requirements engineering methodology called Secure Tropos which has been extended to support MEC-based SC networks. In the proposed model, critical resources which need protection, and potential security threats are identified. Furthermore, we identify appropriate security constraints and suitable security mechanisms for 5G networks. Thus, we reveal that existing security mechanisms need adaptation to face emerging security threats in 5G networks
Carbon nanostructures derived through hypergolic reaction of conductive polymers with fuming nitric acid at ambient conditions
Hypergolic systems rely on organic fuel and a powerful oxidizer that spontaneously ignites upon contact without any external ignition source. Although their main utilization pertains to rocket fuels and propellants, it is only recently that hypergolics has been established from our group as a new general method for the synthesis of different morphologies of carbon nanostructures depending on the hypergolic pair (organic fuel-oxidizer). In search of new pairs, the hypergolic mixture described here contains polyaniline as the organic source of carbon and fuming nitric acid as strong oxidizer. Specifically, the two reagents react rapidly and spontaneously upon contact at ambient conditions to afford carbon nanosheets. Further liquid-phase exfoliation of the nanosheets in dimethylformamide results in dispersed single layers exhibiting strong Tyndall effect. The method can be extended to other conductive polymers, such as polythiophene and polypyrrole, leading to the formation of different type carbon nanostructures (e.g., photolumincent carbon dots). Apart from being a new synthesis pathway towards carbon nanomaterials and a new type of reaction for conductive polymers, the present hypergolic pairs also provide a novel set of rocket bipropellants based on conductive polymers.Web of Science266art. no. 159
Theta dependence of SU(N) gauge theories in the presence of a topological term
We review results concerning the theta dependence of 4D SU(N) gauge theories
and QCD, where theta is the coefficient of the CP-violating topological term in
the Lagrangian. In particular, we discuss theta dependence in the large-N
limit.
Most results have been obtained within the lattice formulation of the theory
via numerical simulations, which allow to investigate the theta dependence of
the ground-state energy and the spectrum around theta=0 by determining the
moments of the topological charge distribution, and their correlations with
other observables. We discuss the various methods which have been employed to
determine the topological susceptibility, and higher-order terms of the theta
expansion. We review results at zero and finite temperature. We show that the
results support the scenario obtained by general large-N scaling arguments, and
in particular the Witten-Veneziano mechanism to explain the U(1)_A problem. We
also compare with results obtained by other approaches, especially in the
large-N limit, where the issue has been also addressed using, for example, the
AdS/CFT correspondence.
We discuss issues related to theta dependence in full QCD: the neutron
electric dipole moment, the dependence of the topological susceptibility on the
quark masses, the U(1)_A symmetry breaking at finite temperature.
We also consider the 2D CP(N) model, which is an interesting theoretical
laboratory to study issues related to topology. We review analytical results in
the large-N limit, and numerical results within its lattice formulation.
Finally, we discuss the main features of the two-point correlation function
of the topological charge density.Comment: A typo in Eq. (3.9) has been corrected. An additional subsection
(5.2) has been inserted to demonstrate the nonrenormalizability of the
relevant theta parameter in the presence of massive fermions, which implies
that the continuum (a -> 0) limit must be taken keeping theta fixe
Ramucirumab plus docetaxel versus placebo plus docetaxel in patients with locally advanced or metastatic urothelial carcinoma after platinum-based therapy (RANGE): a randomised, double-blind, phase 3 trial
Few treatments with a distinct mechanism of action are available for patients with platinum-refractory advanced or metastatic urothelial carcinoma. We assessed the efficacy and safety of treatment with docetaxel plus either ramucirumab-a human IgG1 VEGFR-2 antagonist-or placebo in this patient population
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