974 resultados para Security protocols


Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Las redes móviles ad hoc son redes formadas por lainterconexión de terminales inalámbricos que de manera autónoma,sin ninguna administración central, establecen enlaces decomunicación entre ellos. La infraestructura de red la componenlos propios terminales de usuarios que actúan de gestores yencaminadores de paquetes. Así, un usuario cualquiera puedeconectarse con un terminal remoto a través de una conexiónmultisalto entre diferentes usuarios. En este tipo de redes tanabiertas, uno de los retos prioritarios es proteger el anonimatode los sujetos y sus localizaciones. En este artículo hacemos unrepaso de las técnicas existentes a través de los protocolos que sehan propuesto en la literatura, y exponemos los problemas queaun quedan abiertos.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper describes the state of the art of secure ad hoc routing protocols and presents SEDYMO, a mechanism to secure a dynamic multihop ad hoc routing protocol. The proposed solution defeats internal and external attacks usinga trustworthiness model based on a distributed certification authority. Digital signatures and hash chains are used to ensure the correctness of the protocol. The protocol is compared with other alternatives in terms of security strength, energy efficiency and time delay. Both computational and transmission costs are considered and it is shown that the secure protocol overhead is not a critical factor compared to the high network interface cost.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Los mecanismos de seguridad son uno de losrequisitos fundamentales para el buen funcionamiento de los protocolos de redes ad hoc móviles. En este artículo se analizan los problemas de seguridad de los protocolos de encaminamiento básicos, se describen las soluciones de seguridad existentes, y se hace un estudio del coste computacional y energético que supone para el sistema la inclusión de mecanismosde seguridad.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The use of open source software continues to grow on a daily basis. Today, enterprise applications contain 40% to 70% open source code and this fact has legal, development, IT security, risk management and compliance organizations focusing their attention on its use, as never before. They increasingly understand that the open source content within an application must be detected. Once uncovered, decisions regarding compliance with intellectual property licensing obligations must be made and known security vulnerabilities must be remediated. It is no longer sufficient from a risk perspective to not address both open source issues.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work was to evaluate the effects of hormonal synchronization protocols, associated or not with follicular development stimulation, on the recovery of oocytes and on in vitro production of Bos indicus and B. taurus embryos, in different seasons. Ultrasound-guided follicular aspirations (n=237) were performed without pre-treatment (G1, control group) and after follicular wave synchronization (G2), or after follicular wave synchronization and follicle growth induction (G3). Bos indicus produced more oocytes and embryos than B. taurus (18.7±0.9 vs. 11.9±0.6 oocytes and 4.8±0.3 vs. 2.1±0.2 embryos). On average, oocyte and embryo yields were higher in G3 than in G2, and both were greater than in G1, which lead to a higher conversion of oocytes to embryos in these treatments. The hot or the cold season did not affect the B. indicus outcomes, whereas, in B. taurus, both oocyte recovery and embryo production were higher in the cold season. Follicular wave synchronization improves ovum pick-up and in vitro production of embryos in both cattle subspecies evaluated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Recent efforts to implement gender mainstreaming in the field of security sector reform have resulted in an international policy discourse on gender and security sector reform (GSSR). Critics have challenged GSSR for its focus on 'adding women' and its failure to be transformative. This article contests this assessment, demonstrating that GSSR is not only about 'adding women', but also, importantly, about 'gendering men differently' and has important albeit problematic transformative implications. Drawing on poststructuralist and postcolonial feminist theory, I propose a critical reading of GSSR policy discourse in order to analyse its built-in logics, tensions and implications. I argue that this discourse establishes a powerful 'grid of intelligibility' that draws on gendered and racialized dualisms to normalize certain forms of subjectivity while rendering invisible and marginalizing others, and contributing to reproduce certain forms of normativity and hierarchy. Revealing such processes of discursive in/exclusion and marginalized subjectivities can serve as a starting point to challenge and transform GSSR practice and identify sites of contestation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aquest projecte inclou una aproximació als conceptes de RFID i targetes contactless centrant-se en l’ampliament usat MIFARE Classic chip. L’objectiu principal es mostrar el seu funcionament i les seves vulnerabilitats, així com alguns exemples pràctics fent una anàlisi de diferents serveis que les utilitzen.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The global human population is expected to reach ∼9 billion by 2050. Feeding this many people represents a major challenge requiring global crop yield increases of up to 100%. Microbial symbionts of plants such as arbuscular mycorrhizal fungi (AMF) represent a huge, but unrealized resource for improving yields of globally important crops, especially in the tropics. We argue that the application of AMF in agriculture is too simplistic and ignores basic ecological principals. To achieve this challenge, a community and population ecology approach can contribute greatly. First, ecologists could significantly improve our understanding of the determinants of the survival of introduced AMF, the role of adaptability and intraspecific diversity of AMF and whether inoculation has a direct or indirect effect on plant production. Second, we call for extensive metagenomics as well as population genomics studies that are crucial to assess the environmental impact that introduction of non-local AMF may have on native AMF communities and populations. Finally, we plead for an ecologically sound use of AMF in efforts to increase food security at a global scale in a sustainable manner.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Postmortem MRI (PMMR) examinations are seldom performed in legal medicine due to long examination times, unfamiliarity with the technique, and high costs. Furthermore, it is difficult to obtain access to an MRI device used for patients in clinical settings to image an entire human body. An alternative is available: ex situ organ examination. To our knowledge, there is no standardized protocol that includes ex situ organ preparation and scanning parameters for postmortem MRI. Thus, our objective was to develop a standard procedure for ex situ heart PMMR examinations. We also tested the oily contrast agent Angiofil® commonly used for PMCT angiography, for its applicability in MRI. We worked with a 3 Tesla MRI device and 32-channel head coils. Twelve porcine hearts were used to test different materials to find the best way to prepare and place organs in the device and to test scanning parameters. For coronary MR angiography, we tested different mixtures of Angiofil® and different injection materials. In a second step, 17 human hearts were examined to test the procedure and its applicability to human organs. We established two standardized protocols: one for preparation of the heart and another for scanning parameters based on experience in clinical practice. The established protocols enabled a standardized technical procedure with comparable radiological images, allowing for easy radiological reading. The performance of coronary MR angiography enabled detailed coronary assessment and revealed the utility of Angiofil® as a contrast agent for PMMR. Our simple, reproducible method for performing heart examinations ex situ yields high quality images and visualization of the coronary arteries.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The control of the right application of medical protocols is a key issue in hospital environments. For the automated monitoring of medical protocols, we need a domain-independent language for their representation and a fully, or semi, autonomous system that understands the protocols and supervises their application. In this paper we describe a specification language and a multi-agent system architecture for monitoring medical protocols. We model medical services in hospital environments as specialized domain agents and interpret a medical protocol as a negotiation process between agents. A medical service can be involved in multiple medical protocols, and so specialized domain agents are independent of negotiation processes and autonomous system agents perform monitoring tasks. We present the detailed architecture of the system agents and of an important domain agent, the database broker agent, that is responsible of obtaining relevant information about the clinical history of patients. We also describe how we tackle the problems of privacy, integrity and authentication during the process of exchanging information between agents.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Key management has a fundamental role in secure communications. Designing and testing of key management protocols is tricky. These protocols must work flawlessly despite of any abuse. The main objective of this work was to design and implement a tool that helps to specify the protocol and makes it possible to test the protocol while it is still under development. This tool generates compile-ready java code from a key management protocol model. A modelling method for these protocols, which uses Unified Modeling Language (UML) was also developed. The protocol is modelled, exported as an XMI and read by the code generator tool. The code generator generates java code that is immediately executable with a test software after compilation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The networking and digitalization of audio equipment has created a need for control protocols. These protocols offer new services to customers and ensure that the equipment operates correctly. The control protocols used in the computer networks are not directly applicable since embedded systems have resource and cost limitations. In this master's thesis the design and implementation of new loudspeaker control network protocols are presented. The protocol stack was required to be reliable, have short response times, configure the network automatically and support the dynamic addition and removal of loudspeakers. The implemented protocol stack was also required to be as efficient and lightweight as possible because the network nodes are fairly simple and lack processing power. The protocol stack was thoroughly tested, validated and verified. The protocols were formally described using LOTOS (Language of Temporal Ordering Specifications) and verified using reachability analysis. A prototype of the loudspeaker network was built and used for testing the operation and the performance of the control protocols. The implemented control protocol stack met the design specifications and proved to be highly reliable and efficient.