Column-based databases: estudo exploratório no âmbito das bases de dados NoSQL

Dissertação de mestrado integrado em Engenharia e Gestão de Sistemas de Informação

Document-based databases: estudo comparativo no âmbito das bases de dados NoSql

Dissertação de mestrado integrado em Engenharia e Gestão de Sistemas de Informação

Priming of a DNA metabarcoding approach for species identification and inventory in marine macrobenthic communities

Dissertação de mestrado em Molecular Genetics

Biblioteca de referência de DNA barcodes de bivalves (Mollusca: Bivalvia) e gastrópodes (Mollusca: Gastropoda) da costa Portuguesa

Dissertação de mestrado em Ecologia

On propositionalization for knowledge discovery in relational databases

Propositionalization, Inductive Logic Programming, Multi-Relational Data Mining

Mechanisms Involved in Exercise-Induced Cardioprotection: A Systematic Review

Background:Acute myocardial infarction is the leading cause of morbidity and mortality worldwide. Furthermore, research has shown that exercise, in addition to reducing cardiovascular risk factors, can also protect the heart against injury due to ischemia and reperfusion through a direct effect on the myocardium. However, the specific mechanism involved in exerciseinduced cardiac preconditioning is still under debate.Objective:To perform a systematic review of the studies that have addressed the mechanisms by which aerobic exercise promotes direct cardioprotection against ischemia and reperfusion injury.Methods:A search was conducted using MEDLINE, Literatura Latino-Americana e do Caribe de Informação em Ciências da Saúde, and Scientific Electronic Library Online databases. Data were extracted in a standardized manner by two independent researchers, who were responsible for assessing the methodological quality of the studies.Results:The search retrieved 78 studies; after evaluating the abstracts, 30 studies were excluded. The manuscripts of the remaining 48 studies were completely read and, of these, 20 were excluded. Finally, 28 studies were included in this systematic review.Conclusion:On the basis of the selected studies, the following are potentially involved in the cardioprotective response to exercise: increased heat shock protein production, nitric oxide pathway involvement, increased cardiac antioxidant capacity, improvement in ATP-dependent potassium channel function, and opioid system activation. Despite all the previous investigations, further research is still necessary to obtain more consistent conclusions.

Implementation of a unified userspace time handling library under the Linux OS

An appropriate assessment of end-to-end network performance presumes highly efficient time tracking and measurement with precise time control of the stopping and resuming of program operation. In this paper, a novel approach to solving the problems of highly efficient and precise time measurements on PC-platforms and on ARM-architectures is proposed. A new unified High Performance Timer and a corresponding software library offer a unified interface to the known time counters and automatically identify the fastest and most reliable time source, available in the user space of a computing system. The research is focused on developing an approach of unified time acquisition from the PC hardware and accordingly substituting the common way of getting the time value through Linux system calls. The presented approach provides a much faster means of obtaining the time values with a nanosecond precision than by using conventional means. Moreover, it is capable of handling the sequential time value, precise sleep functions and process resuming. This ability means the reduction of wasting computer resources during the execution of a sleeping process from 100% (busy-wait) to 1-1.5%, whereas the benefits of very accurate process resuming times on long waits are maintained.

Serial publications in the British Museum (Natural History) Library.

1 (A-F)

Serial publications in the British Museum (Natural History) Library.

2 (G-Q)

Serial publications in the British Museum (Natural History) Library.

3 (R-Z)

Efficient query processing in co-processor-accelerated databases

...Diese Dissertation zeigt, wie wir Datenbankmanagementsysteme bauen können, die heterogene Prozessoren effizient und zuverlässig zur Beschleunigung der Anfrageverarbeitung nutzen können. Daher untersuchen wir typische Entwurfsentscheidungen von coprozessorbeschleunigten Datenbankmanagementsystemen und leiten darauf aufbauend eine generische Architektur für solche Systeme ab. Unsere Untersuchungen zeigen, dass eines der wichtigsten Probleme für solche Datenbankmanagementsysteme die Entscheidung ist, welche Operatoren einer Anfrage auf welchem Prozessor ausgeführt werden sollen...

Applying RADIC in Open MPI: the methodology used to implement RADIC over a Message Passing Library

Fault tolerance has become a major issue for computer and software engineers because the occurrence of faults increases the cost of using a parallel computer. RADIC is the fault tolerance architecture for message passing systems which is transparent, decentralized, flexible and scalable. This master thesis presents the methodology used to implement the RADIC architecture over Open MPI, a well-know large-used message passing library. This implementation kept the RADIC architecture characteristics. In order to validate the implementation we have executed a synthetic ping program, besides, to evaluate the implementation performance we have used the NAS Parallel Benchmarks. The results prove that the RADIC architecture performance depends on the communication pattern of the parallel application which is running. Furthermore, our implementation proves that the RADIC architecture could be implemented over an existent message passing library.

Memòria de recerca: paral·lelització dels diccionaris de la Standard Template Library de C++

Estudi elaborat a partir d’una estada a la Universität Karlsruhe entre gener i maig del 2007. Les biblioteques d’estructures de dades defineixen interfícies i implementen algorismes i estructures de dades fonamentals. Un exemple n’és la Satandard Template Library (STL ), que forma part del llenguatge de programació C++. En el marc d’una tesi, s’està treballant per obtenir implementacions més eficients i/o versàtils d’alguns components de la STL. Per a fer-ho s’utilitzen tècniques de la enginyeria d’algorismes. En particular, s’integra el coneixement de la comunitat algorítmica i es té en consideració la tecnologia existent. L’acció durant l’estada s’ha emmarcat en el desenvolupament la Multi Core STL (MCSTL ). La MCSTL és una implementació paral•lela de la STL per a màquines multi-core. Les màquines multi-core són actualment l’únic tipus de màquina disponible al mercat. Per tant, tot i que el paral•lelisme obtingut no sigui òptim, és preferible a tenir els processadors esperant, ja que , la tendència és que el nombre de processadors per computador augmenti.