Asynchronous sequential symbol synchronizers based on pulse comparison by both transitions at half bit rate

This work studies the asynchronous sequential symbol synchronizers based on pulse comparison by both transitions at half bit rate. Their performance will be compared with the reference asynchronous symbol synchronizers based on pulse comparison by both transitions at bit rate. For the reference and proposed variants, we consider two versions which are the manual (m) and the automatic (a). The objective is to study the four synchronizers and evaluate their output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal Noise Ratio)

Asynchronous sequential symbol synchronizers based on pulse comparison by positive transitions at half bit rate

This work presents the asynchronous sequential symbol synchronizers based on pulse comparison by positive transitions at half bit rate. Their performance will be compared with the reference asynchronous symbol synchronizers based on pulse comparison by both transitions at bit rate. For the reference and proposed variants, we consider two versions which are the manual (m) and the automatic (a). The objective is to study the four synchronizers and evaluate their output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal Noise Ratio)

Laitiers d’aciérie portugaise : un nouveau géomatériau

The engineering properties of Portuguese processed steel slags (ISACs) are tested to evaluate the appropriateness of their use in transportation infrastructures and geotechnical works. The laboratory results are compared with values specified in the Portuguese standards for natural aggregates and with values found for natural aggregates of various geological origins. The elastic modulus is carefully evaluated in order to compare the two ISACs with two standard base coarse materials (granite aggregate 0/31.5mm and limestone aggregate 0/19mm). All laboratory results show that the national processed steel slags could be used in geotechnical works, and particularly in transportation infrastructures. The two ISACs demonstrated better mechanical properties than the standard, unbound, granular base, coarse materials.Dans cet article sont présentés les résultats d'essai en laboratoire pour évaluer les propriétés des agrégats laitiers d’aciérie Portugaises (ISAC), dans le but de leur utilisation dans des infrastructures de transport et des travaux géotechniques. Les résultats sont comparés aux valeurs indiquées dans les normes portugaises pour les agrégats traditionnels et avec des valeurs trouvées pour les agrégats naturels de différentes origines géologiques. Une attention particulière est faite en termes du module élastique, comparant les deux ISACs, à deux matériaux standards de sous-couches de chaussées (agrégat 0/31.5mm de granite et agrégat 0/19mm de calcaire). Tous les résultats de laboratoire montrent que les laitiers d’aciérie Portugaises pourraient être employés dans les travaux géotechniques, et en particulier dans les infrastructures de transport. On l'a également expérimentalement observé que les deux ISACs ont de meilleures propriétés mécaniques que les matériaux non traités des sous-couches des chaussées.FEDERFundação para a Ciência e a Tecnologia (FCT) - POCI/ECM/56952/2004POCI 201

Use of non traditional materials in geotechnical works – valorisation of nacional steel slags

Para avaliar a viabilidade de utilização dos ASIC (Agregado Siderúrgico Inerte para Construção) produzidos pela Siderurgia Nacional, em obras geotécnicas, estudam-se em laboratório as suas propriedades mineralógicas, químicas, geométricas, físicas e mecânicas. Neste trabalho apresentam-se os resultados obtidos para as propriedades mecânicas designadamente, a rigidez estudada através de um equipamento triaxial de precisão. Os resultados são comparados com os obtidos em materiais especificados para as camadas de base dos pavimentos, quer em Portugal, quer em França (agregados granítico 0/31,5 e calcário 0/19, respectivamente). Da comparação dos resultados conclui-se que os ASIC apresentam propriedades mecânicas superiores às dos agregados naturais. Estes resultados enfatizam que os ASIC nacionais podem ser utilizados em obras geotécnicas, muito particularmente nas infra-estruturas de transporte.To evaluate the re-use of ASIC (Inert Steel Aggregate for Construction) produced by Siderurgia Nacional in geotechnical constructions viability, a huge laboratory experimental programme was implemented to study the mineralogical, chemical, geometrical, physical and mechanical properties. In this paper are presented the results obtained by laboratory performance-related tests for mechanical properties, namely the stiffness, studied by means of precision triaxial tests. The results obtained for the two steel slags, were compared with a standard base course materials used at Portugal and at France (granite 0/31,5 and limestone aggregate 0/19, respectively). The results obtained show that ASIC have better mechanical properties than a standard base course materials. These results emphasize that the ASIC produced at Portugal could be used in geotechnical works, and particularly in transportation infrastructures.Universidade de Coimbra. Faculdade de Ciências e Tecnologia (FCT-UC)Fundação para a Ciência e a Tecnologia (FCT) - (POCI/ECM/56952/2004)Siderurgia Nacional (SN

Processed Portuguese steel slag: a new geomaterial

The management strategy for waste, in which the prevention of its produc- tion is not yet feasible, should lead to the prioritization of the exploitation of its performance potential, especially through re-use solutions. On this basis, a Research and Development Project is under way in Portugal, which is intended to re-use the processed steel slags pro- duced in the two Portuguese Companies. In this paper are presented the results obtained by laboratory performance-related tests for geometrical, physical and mechanical properties for the two Portuguese processed steel slags, named Inert Steel Aggregates for Construction (ISAC). A special emphasis is made in terms of elastic modulus, comparing the two ISACs, with two standard base course materials (granite and limestone aggregates). The laboratory results show that the ISACs could be used in transportation infrastructures. It was also exper- imentally observed that the two ISACs have better mechanical properties than the standard unbound granular base course materials.University of Illinois at Urbana-Champaig, Illinois Center for Transportation, Center of Excellence for Airport Pavement Research, University of Illinois Railroad Engineering Program, Illinois Department of Transportation, U.S. Department of Transportation, Federal Aviation Administration, Association of American Railroads, Transportation Research Board, American Society of Civil Engineer

Propriedades do ASIC da siderurgia nacional e possibilidades da sua utilização em obra : uma perspectiva geomecânica

Para avaliar a viabilidade de utilização dos ASIC (Agregado Siderúrgico Inerte para Construção) produzidos pela Siderurgia Nacional, em obras geotécnicas, estudam-se em laboratório as suas propriedades mineralógicas, químicas, geométricas, físicas e mecânicas. Neste trabalho apresentam-se os resultados obtidos para as propriedades físicas e mecânicas, em particular a rigidez estudada através de um equipamento triaxial de precisão. Os resultados são comparados com os obtidos em materiais especificados para as camadas de base dos pavimentos, quer em Portugal, quer em França (agregados granítico 0/31,5 e calcário 0/19, respectivamente). Da comparação dos resultados conclui-se que os ASIC apresentam propriedades mecânicas superiores às dos agregados naturais. Estes resultados enfatizam que os ASIC nacionais podem ser utilizados nas infra-estruturas de transporte

Materials research by nuclear reaction analysis

This article is about computer simulation for surface analysis through nuclear techniques, which are non-destructive. The energy analysis method is used. Energy spectra are computer simulated and compared to experimental data, giving sample composition and concentration profiles. The method is successfully applied to depth profiling of 12C nuclei in a thick target, using the 12C(d,p0)13C deuteron induced reaction. Scanning electron microscopy is used as a complementary technique, to give information about surface topography.University of Beira Interiorinfo:eu-repo/semantics/publishedVersio

Materials research by elastic scattering analysis

This article is about computer simulation for surface analysis through nuclear techniques, which are non-destructive. The energy analysis method is used. Energy spectra are computer simulated and compared to experimental data, giving sample composition and concentration profiles. The method, using elastic scattering of (4He)+ ions, is successfully applied to depth profiling in both thin and thick targets containing Al and O.University of Beira Interior.info:eu-repo/semantics/publishedVersio

Towards an accurate evaluation of deduplicated storage systems

Deduplication has proven to be a valuable technique for eliminating duplicate data in backup and archival systems and is now being applied to new storage environments with distinct requirements and performance trade-offs. Namely, deduplication system are now targeting large-scale cloud computing storage infrastructures holding unprecedented data volumes with a significant share of duplicate content. It is however hard to assess the usefulness of deduplication in particular settings and what techniques provide the best results. In fact, existing disk I/O benchmarks follow simplistic approaches for generating data content leading to unrealistic amounts of duplicates that do not evaluate deduplication systems accurately. Moreover, deduplication systems are now targeting heterogeneous storage environments, with specific duplication ratios, that benchmarks must also simulate. We address these issues with DEDISbench, a novel micro-benchmark for evaluating disk I/O performance of block based deduplication systems. As the main contribution, DEDISbench generates content by following realistic duplicate content distributions extracted from real datasets. Then, as a second contribution, we analyze and extract the duplicates found on three real storage systems, proving that DEDISbench can easily simulate several workloads. The usefulness of DEDISbench is shown by comparing it with Bonnie++ and IOzone open-source disk I/O micro-benchmarks on assessing two open-source deduplication systems, Opendedup and Lessfs, using Ext4 as a baseline. Our results lead to novel insight on the performance of these file systems.This work is funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT - Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) within project RED FCOMP-01-0124-FEDER-010156 and FCT by Ph.D scholarship SFRH-BD-71372-2010

DEDISbench: a benchmark for deduplicated storage systems

Lecture Notes in Computer Science, 7566Deduplication is widely accepted as an effective technique for eliminating duplicated data in backup and archival systems. Nowadays, deduplication is also becoming appealing in cloud computing, where large-scale virtualized storage infrastructures hold huge data volumes with a significant share of duplicated content. There have thus been several proposals for embedding deduplication in storage appliances and file systems, providing different performance trade-offs while targeting both user and application data, as well as virtual machine images. It is however hard to determine to what extent is deduplication useful in a particular setting and what technique will provide the best results. In fact, existing disk I/O micro-benchmarks are not designed for evaluating deduplication systems, following simplistic approaches for generating data written that lead to unrealistic amounts of duplicates. We address this with DEDISbench, a novel micro-benchmark for evaluating disk I/O performance of block based deduplication systems. As the main contribution, we introduce the generation of a realistic duplicate distribution based on real datasets. Moreover, DEDISbench also allows simulating access hotspots and different load intensities for I/O operations. The usefulness of DEDISbench is shown by comparing it with Bonnie++ and IOzone open-source disk I/O micro-benchmarks on assessing two open-source deduplication systems, Opendedup and Lessfs, using Ext4 as a baseline. As a secondary contribution, our results lead to novel insight on the performance of these file systems.(undefined