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Publications

Publications by CRIIS

2014

Towards Certifiable Adaptive Reservations for Hypervisor-based Virtualization

Authors
Groesbrink, S; Almeida, L; de Sousa, M; Petters, SM;

Publication
2014 IEEE 20TH REAL-TIME AND EMBEDDED TECHNOLOGY AND APPLICATIONS SYMPOSIUM (RTAS)

Abstract
Hypervisor-based virtualization provides a natural way to integrate formerly distinct systems into a single mixed-criticality multicore system by consolidating in separated virtual machines. We propose an adaptive computation bandwidth management for such architectures, which is compatible with a potential certification based on the guarantee of specified bandwidth minimums and the isolation of overruns of virtual machines. This management uses periodic servers and an elastic task model to combine analyzability at design time with adaptability at runtime. Mode changes or early termination of VMs trigger a resource redistribution that reassigns spare capacity. In this paper we focus on the integration of an adaptive reservation policy into a virtualization software stack and the co-design of hypervisor and paravirtualized guest operating system. In a concrete implementation on a PowerPC 405, the bandwidth distribution policy incurred in a memory footprint below 2.7KB and a worst-case execution time for the redistribution function below 4 microseconds for realistic low numbers of VMs. Simulations over synthetically generated sets of VMs with random mode changes showed a gain of 13% of computation bandwidth when compared to an approach with fixed partitions and provided a relative error of allocated bandwidth to desired bandwidth 4 times lower.

2014

Guaranteeing replica determinism on IEC 61499

Authors
De Sousa, M;

Publication
19th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2014

Abstract
Being distributed in nature, IEC 61499 industrial control applications are subject to partial failures. Building applications that are tolerant of these failures (i.e. a fault-tolerant application) may be achieved through the use of replication. In this paper we present a framework to support replicated IEC 61499 applications, and study how replica determinism may be achieved in this framework. © 2014 IEEE.

2014

Effects of the dietary incorporation of olive leaves on growth performance, digestibility, blood parameters and meat quality of growing pigs

Authors
Paiva Martins, F; Ribeirinha, T; Silva, A; Goncalves, R; Pinheiro, V; Mourao, JL; Outor Monteiro, D;

Publication
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

Abstract
BACKGROUND: In a preliminary study the oxidative stability and tocopherol content of pork meat were shown to be improved by olive leaf (OL) feed supplementation at 50 and 100 g kg(-1). However, growth performance was affected negatively. Therefore the objective of the present study was to assess the influence of OL supplementation at a lower level on feed digestibility, growth performance and meat quality. RESULTS: Pigs were fed a basal diet (control), a basal diet with 25 g OL kg(-1) (OL2.5) or a basal diet with 50 g OL kg(-1) (OL5). The incorporation of OL significantly decreased growth rates (P = 0.010) and backfat thickness (P = 0.035) and increased feed/gain ratio (P = 0.032) in the OL5 group. Feed/gain ratio increased more for females (P = 0.001). The incorporation of OL decreased the crude fat (P = 0.006) and protein (P = 0.037) digestibility of both OL diets. Nevertheless, OL was effective in increasing the tocopherol content of meat (P = 0.009). However, meat from pigs fed the OL diets showed similar conjugated diene content, pH and colour parameters to that from pigs fed the control diet, even after 6 days of storage at 4 degrees C. CONCLUSION: The data indicate that olive leaves may be included in pig diets at 25 g kg(-1) in order to improve the tocopherol content of meat without excessively compromising growth performance. (C) 2014 Society of Chemical Industry

2014

Distributed Prime Sieve in Heterogeneous Computer Clusters

Authors
Costa, CM; Sampaio, AM; Barbosa, JG;

Publication
COMPUTATIONAL SCIENCE AND ITS APPLICATIONS - ICCSA 2014, PT IV

Abstract
Prime numbers play a pivotal role in current encryption algorithms and given the rise of cloud computing, the need for larger primes has never been so high. This increase in available computation power can be used to either try to break the encryption or to strength it by finding larger prime numbers. With this in mind, this paper provides an analysis of different sieve implementations that can be used to generate primes to near 2(64). It starts by analyzing cache friendly sequential sieves with wheel factorization, then expands to multi-core architectures and ends with a cache friendly segmented hybrid implementation of a distributed prime sieve, designed to efficiently use all the available computation resources of heterogeneous computer clusters with variable workload and to scale very well in both the shared and distributed memory versions.

2014

Proposal of an Information System for an Adaptive Mixed Reality System for Archaeological Sites

Authors
Magalhaes, LG; Sousa, JJ; Bento, R; Adao, T; Pereira, F; Filipe, V; Peres, E;

Publication
CENTERIS 2014 - CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS / PROJMAN 2014 - INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT / HCIST 2014 - INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES

Abstract
The use of Augmented Reality (AR) techniques to visualize virtual archaeological sites is neither a new or recent issue. In those approaches the virtual models are only visualized using the existent in situ illumination, which does not allow a visitor to have a similar visual experience to that which he would have at the time the structures were built. In Augmented Virtuality (AV) approaches the virtual world prevails, which is augmented with information from the real world, which allows a better control over the parameters of the Mixed Reality (MR) environment created. In some cases, there is the need to use both approaches (AR or AV), depending on some context conditions. This paper proposes an architecture and an information system for an adaptive MR system which main goal is to visualize in situ virtual reconstructions of archaeological sites that are seamlessly merged with the real scene. In this context, a new adaptive methodology will be defined to manage the level of mixing between the real and the virtual scene, identifying in each instant the most proper approach to use (AR or AV), as well as defining the way how transitions between approaches are made. (C) 2014 The Authors. Published by Elsevier Ltd.

2014

Multi-temporal InSAR for deformation monitoring of the Granada and Padul faults and the surrounding area (Betic Cordillera, southern Spain)

Authors
Sousa, JJ; Ruiz, AM; Hooper, AJ; Hanssen, RF; Perski, Z; Bastos, LC; Gil, AJ; Galindo Zaldivar, J; Sanz de Galdeano, CS; Alfaro, P; Selmira Garrido, MS; Armenteros, JA; Gimenez, E; Aviles, M;

Publication
CENTERIS 2014 - CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS / PROJMAN 2014 - INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT / HCIST 2014 - INTERNATIONAL CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES

Abstract
The quantification of low rate active tectonic structures is a major target of geodetic and geological studies to improve the knowledge of seismic hazards. The central Betic Cordillera (southern Spain) is affected by moderately active tectonic structures and seismicity. Part of this seismic activity is produced by several NW-SE normal faults located in the E of the Granada Basin. Here, we apply Multi-temporal InSAR (MTI) data to quantify the deformation produced by the Granada fault and the Padul fault zones and the surrounding area. The Granada NW-SE active normal fault zone, 17 km in length, crosses the city of Granada, a very sensitive area from a seismic hazard point of view due to the population of the Granada town. At the Padul fault, there is no geodetic evidence of contemporary motion. Considering the evidence of recent activity from geologic data, this fault may experience discontinuous motion with a different seismogenic character. Despite the InSAR uncertainties, InSAR results are consistent with the estimated geologic deformation rates lower than 1 mm/yr. Our results also confirm previous InSAR studies in the Otura area showing an estimated average annual velocity along the SAR line-of-sight of up to 10 mm/year anthropogenic subsidence. (C) 2014 The Authors. Published by Elsevier Ltd.

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