2014
Autores
Bessa, N; Fontes, DBMM;
Publicação
PROCEEDINGS OF THE 18TH INTERNATIONAL DATABASE ENGINEERING AND APPLICATIONS SYMPOSIUM (IDEAS14)
Abstract
This research aims to help in establishing new legislative directives by testing their impact both on the company profits and on the life of city residents. A case study is developed and conducted in collaboration with the city hall and with eight companies (four freight transport companies and four retailer companies). The impacts are computed by simulating the companies operation under the new legislation and the new routes are used to analyze the impacts on the city traffic, noise, and congestion.
2014
Autores
Areias, M; Rocha, R;
Publicação
PADL
Abstract
Tabling is an implementation technique that improves the declarativeness and expressiveness of Prolog in dealing with recursion and redundant sub-computations. A critical component in the implementation of an efficient tabling framework is the design of the data structures and algorithms to access and manipulate tabled data. One of the most successful data structures for tabling is tries. In previous work, our initial approach to deal with concurrent table accesses, implemented on top of the Yap Prolog system, was to use lock-based trie data structures. In this work, we propose a new design based on lock-free data structures and, in particular, we focus our discussion on the correctness and efficiency of extending Yap's tabling framework to support lock-free expandable tries. Experimental results show that our new lock-free design can effectively reduce the execution time and scale better, when increasing the number of threads, than the original lock-based design. © 2014 Springer International Publishing.
2014
Autores
Groesbrink, S; Almeida, L; de Sousa, M; Petters, SM;
Publicação
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
Autores
Vanschoren, J; Brazdil, P; Soares, C; Kotthoff, L;
Publicação
MetaSel@ECAI
Abstract
2014
Autores
Loureiro, B; Rodrigues, R;
Publicação
ACHI 2014 - 7th International Conference on Advances in Computer-Human Interactions
Abstract
The usage of multi-touch interfaces on a tabletop device, has been very explored for elder users in several domains. This interaction technique is an alternative to reducing the obstacles that older adults face in the use of computer systems, e.g., handling of peripherals. Many design guidelines are proposed in the literature for a wide range of products and systems for elders, e.g. websites, TV user interfaces. However, there is a lack of set of design guidelines and design recommendations of multi-touch interfaces that matches elder's needs. This paper presents a set of design guidelines and design recommendations distilled and extracted from most relevant works on design of multi-touch interfaces for elders available in the literature. The results are a set of design guidelines, useful for designers, application developers, usability specialists and researchers. Copyright © IARIA, 2014.
2014
Autores
Silva, S; Coelho, L; Frazao, O;
Publicação
MEASUREMENT
Abstract
A gas pressure sensor based on an all-fiber Fabry-Perot interferometer (FFPI) is reported. The sensing head consists of a small section of silica rod spliced with a large offset between two single-mode fibers. The silica rod is used only as mechanical support so that an air cavity can be formed between both SMF. It is shown that the FFPI sensor is sensitive to gas pressure variation and when submitted to different gaseous environments, namely carbon dioxide, nitrogen and oxygen - sensitivities of 6.2, 4.1 and 3.6 nm/MPa, respectively, were attained. The refractive index change on nitrogen environment by means of gas pressure variation was also determined and a sensitivity of 1526 nm/RIU was obtained. The response of the sensing device to temperature variations in air was also studied and a sensitivity of -14 pm/degrees C was attained.
The access to the final selection minute is only available to applicants.
Please check the confirmation e-mail of your application to obtain the access code.