Una publicación de acceso abierto: desarrollo, copyright, visibilidad e impacto

Electronic publications open access to medical content have increased in recent years due to the advances in computer engineering and telecommunications. Summarizes aspects of editing, publishing, visibility and impact measurement and the rights of authors and readers

Vulnerability-Tolerant Transport Layer Security

SSL/TLS communication channels play a very important role in Internet security, including cloud computing and server infrastructures. There are often concerns about the strength of the encryption mechanisms used in TLS channels. Vulnerabilities can lead to some of the cipher suites once thought to be secure to become insecure and no longer recommended for use or in urgent need of a software update. However, the deprecation/update process is very slow and weeks or months can go by before most web servers and clients are protected, and some servers and clients may never be updated. In the meantime, the communications are at risk of being intercepted and tampered by attackers. In this paper we propose an alternative to TLS to mitigate the problem of secure commu- nication channels being susceptible to attacks due to unexpected vulnerabilities in its mechan- isms. Our solution, called Vulnerability-Tolerant Transport Layer Security (vtTLS), is based on diversity and redundancy of cryptographic mechanisms and certificates to ensure a secure communication even when one or more mechanisms are vulnerable. Our solution relies on a combination of k cipher suites which ensure that even if k ? 1 cipher suites are insecure or vul- nerable, the remaining cipher suite keeps the communication channel secure. The performance and cost of vtTLS were evaluated and compared with OpenSSL, one of the most widely used implementations of TLS

Laser spot welding of laser textured steel to aluminium

Laser welding of dissimilar metals (steel and aluminium) was investigated with the aim to increase the maximum tensile shear load of the Fe-Al joints. The increase was achieved by texturing the surface of steel prior to the laser spot welding process which was performed in a lap-joint configuration with the steel positioned on top of the aluminium and with a texture faced down to the aluminium surface. This configuration enabled an increase of the bonding area of the joints, because the molten aluminium filled in the gaps of the texture, without the need of increasing the process energy which typically leads to the growth of the intermetallic compounds. Different textures (containing hexagonally arranged craters, parallel lines, grid and spiral patterns) were tested with different laser welding parameters. The Fe-Al joints obtained with the textured steel were found to have up to 25% higher maximum tensile-shear load than the joints obtained with the untextured steel

Does Big Data Require Complex Systems? A Performance Comparison Between Spark and Unicage Shell Scripts

The paradigm of big data is characterized by the need to collect and process data sets of great volume, arriving at the systems with great velocity, in a variety of formats. Spark is a widely used big data processing system that can be integrated with Hadoop to provide powerful abstractions to developers, such as distributed storage through HDFS and resource management through YARN. When all the required configurations are made, Spark can also provide quality attributes, such as scalability, fault tolerance, and security. However, all of these benefits come at the cost of complexity, with high memory requirements, and additional latency in processing. An alternative approach is to use a lean software stack, like Unicage, that delegates most control back to the developer. In this work we evaluated the performance of big data processing with Spark versus Unicage, in a cluster environment hosted in the IBM Cloud. Two sets of experiments were performed: batch processing of unstructured data sets, and query processing of structured data sets. The input data sets were of significant size, ranging from 64 GB to 8192 GB in volume. The results show that the performance of Unicage scripts is superior to Spark for search workloads like grep and select, but that the abstractions of distributed storage and resource management from the Hadoop stack enable Spark to execute workloads with inter-record dependencies, such as sort and join, with correct outputs.Comment: 10 pages, 14 figure

Conteúdo de física exigido nas provas de vestibular

Neste trabalho buscamos identificar quais os conteúdos de Física que fazem parte do programa de Ensino Médioe quais são efetivamente cobrados nas provas de acesso ao Ensino Superior nas principais universidades públicas do Rio de Janeiro. Foram analisadas as provas de Física das cinco universidades mais procuradas nos exames de vestibular do estado entre os anos de 2003 a 2007. Os resultados obtidos nos permitiram detectar uma maior tendência à escolha de questões de Mecânica nessas provas

Una publicación de acceso abierto: desarrollo, copyright, visibilidad e impacto

Electronic publications open access to medical content have increased in recent years due to the advances in computer engineering and telecommunications. Summarizes aspects of editing, publishing, visibility and impact measurement and the rights of authors and readers

Learning to generate Reliable Broadcast Algorithms

Modern distributed systems are supported by fault-tolerant algorithms, like Reliable Broadcast and Consensus, that assure the correct operation of the system even when some of the nodes of the system fail. However, the development of distributed algorithms is a manual and complex process, resulting in scientific papers that usually present a single algorithm or variations of existing ones. To automate the process of developing such algorithms, this work presents an intelligent agent that uses Reinforcement Learning to generate correct and efficient fault-tolerant distributed algorithms. We show that our approach is able to generate correct fault-tolerant Reliable Broadcast algorithms with the same performance of others available in the literature, in only 12,000 learning episodes

Smart meter data processing: a showcase for simple and efficient textual processing

The increase in the production and collection of data from devices is an ongoing trend due to the roll-out of more cyber-physical applications. Smart meters, because of their importance in power grids, are a class of such devices whose produced data requires meticulous processing. In this paper, we use Unicage, a data processing system based on classic Unix shell scripting, that delivers excellent performance in a simple package. We use this methodology to process smart meter data in XML format, subjected to the constraints posed by a real use case. We develop a solution that parses, validates and performs a simple aggregation of 27 million XML files in less than 10 minutes. We present a study of the solution as well as the benefits of its adoption.Comment: 11 pages, 5 figures, 1 table, 9 listings. Accepted after review for the 1st Workshop on High-Performance and Reliable Big Data (HPBD 2021), which was held virtually on September 20th 2021, and was co-located with the 40th International Symposium on Reliable Distributed Systems (SRDS 2021