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Publicações

2015

Well-formed control flow for critical sections in RTFM-core

Autores
Lindgren, P; Lindner, M; Lindner, A; Pereira, D; Pinho, LM;

Publicação
Proceeding - 2015 IEEE International Conference on Industrial Informatics, INDIN 2015

Abstract
The mainstream of embedded software development as of today is dominated by C programming. To aid the development, hardware abstractions, libraries, kernels and lightweight operating systems are commonplace. Such kernels and operating systems typically impose a thread based abstraction to concurrency. However, in general thread based programming is hard, plagued by race conditions and dead-locks. For this paper we take an alternative outset in terms of a language abstraction, RTFM-core, where the system is modelled directly in terms of tasks and resources. In compliance to the Stack Resource Policy (SRP) model, the language enforces (well-formed) LIFO nesting of claimed resources, thus SRP based analysis and scheduling can be readily applied. For the execution onto bare-metal single core architectures, the rtfm-core compiler performs SRP analysis on the model and render an executable that is deadlock free and (through RTFM-kernel primitives) exploits the underlying interrupt hardware for efficient scheduling. The RTFM-core language embeds C-code and links to C-object files and libraries, and is thus applicable to the mainstream of embedded development. However, while the language enforces well-formed resource management, control flow in the embedded C-code may violate the LIFO nesting requirement. In this paper we address this issue by lifting a subset of C into the RTFM-core language allowing arbitrary control flow at the model level. In this way well-formed LIFO nesting can be enforced, and models ensured to be correct by construction. We demonstrate the feasibility by means of a prototype implementation in the rtfm-core compiler. Additionally, we develop a set of running examples and show in detail how control flow is handled at compile time and during run-time execution. © 2015 IEEE.

2015

Some Initial Results and Observations from a Series of Trials within the Ofcom TV White Spaces Pilot

Autores
Holland, O; Ping, S; Sastry, N; Chawdhry, P; Chareau, JM; Bishop, J; Xing, H; Taskafa, S; Aijaz, A; Bavaro, M; Viaud, P; Pinato, T; Angiuli, E; Akhavan, MR; McCann, JA; Gao, Y; Qin, Z; Zhang, Q; Knopp, R; Kaltenberger, F; Nussbaum, D; Dionisio, R; Ribeiro, JC; Marques, P; Hallio, J; Jakobsson, M; Auranen, J; Ekman, R; Kokkinen, H; Paavola, J; Kivinen, A; Solc, T; Mohorcic, M; Tran, HN; Ishizu, K; Matsumura, T; Ibuka, K; Harada, H; Mizutani, K;

Publicação
2015 IEEE 81ST VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING)

Abstract
TV White Spaces (TVWS) technology allows wireless devices to opportunistically use locally-available TV channels enabled by a geolocation database. The UK regulator Ofcom has initiated a pilot of TVWS technology in the UK. This paper concerns a large-scale series of trials under that pilot. The purposes are to test aspects of white space technology, including the white space device and geolocation database interactions, the validity of the channel availability/powers calculations by the database and associated interference effects on primary services, and the performances of the white space devices, among others. An additional key purpose is to perform research investigations such as on aggregation of TVWS resources with conventional resources and also aggregation solely within TVWS, secondary coexistence issues and means to mitigate such issues, and primary coexistence issues under challenging deployment geometries, among others. This paper provides an update on the trials, giving an overview of their objectives and characteristics, some aspects that have been covered, and some early results and observations.

2015

Analog Circuits With High-Gain Topologies Using a-GIZO TFTs on Glass

Autores
Bahubalindruni, PG; Silva, B; Tavares, VG; Barquinha, P; Cardoso, N; de Oliveira, PG; Martins, R; Fortunato, E;

Publicação
JOURNAL OF DISPLAY TECHNOLOGY

Abstract
This paper presents analog building blocks that find potential applications in display panels. A buffer (source-follower), subtractor, adder, and high-gain amplifier, employing only n-type enhancement amorphous gallium-indium-zinc-oxide thin-film transistors (a-GIZO TFTs), were designed, simulated, fabricated, and characterized. Circuit simulations were carried out using a neural model developed in-house from the measured characteristics of the transistors. The adder-subtractor circuit presents a power consumption of 0.26 mW, and the amplifier presents a gain of 34 dB and a power consumption of 0.576 mW, with a load of 10 M Omega//16 pF. To the authors' knowledge, this is the highest gain reported so far for a single-stage amplifier with a-GIZO TFT technology.

2015

Design for Dependability and Autonomy of a Wearable Cardiac and Coronary Monitor

Autores
da Silva, JM; Oliveira, C; Mendes, B; Dias, R; Marques, T;

Publicação
2015 EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN (DSD)

Abstract
Wearable vital signals monitoring systems are promoting new assistance approaches in the healthcare system and are essential for the future connected health paradigm. The present work addresses the design of a cardiac and coronary monitoring system taking into consideration dependability and autonomy issues. A fuzzy logic approach is used to determine, in case deviations in the captured electrocardiogram are detected, whether these are occurring in the patient or in the system. As for autonomy, the use of data compression versus extra data processing balance is analysed to find operating conditions for which compression is worth to be used.

2015

Innovative costing system framework in industrial product-service system environment

Autores
Azevedo, A; Sholihab, M;

Publicação
INDUSTRIAL ENGINEERING AND SERVICE SCIENCE 2015, IESS 2015

Abstract
Product-service system (PSS) or particularly industrial product-service system (IPS2) is started to gain more attention as innovative strategy to face the competitive global market. Service aspect from IPS2 offering is believed could provide more values for customer than the standalone physical product. This new concept is not fully developed yet. There are some particular areas around IPS2 concept which are needed to be more explored and one of them is the cost dimension aspect. Cost is obviously important for company as basic information to support decision making process. Traditional costing system is no longer able to facilitate the company's transformation. The following work will present the analysis of current costing systems and a new assessment framework proposed to address the needs of IPS2 environment, particularly for IPS2 function-oriented business model. The proposed framework is developed based on the literature findings. Considering the specific characteristics of IPS2 business model, lean accounting is the best choice from current costing systems to be adjusted into the proposed framework. Lean accounting with its value stream costing (VSC) is able to provide comprehensive cost information to support company's long transformation journey towards a fully and successful IPS2 company. (C) 2015 The Authors. Published by Elsevier B.V.

2015

Effects of terminology on health queries: An analysis by user's health literacy and topic familiarity

Autores
Lopes, CT; Ribeiro, C;

Publicação
Advances in Librarianship

Abstract
Prior studies have shown that terminology support can improve health information retrieval but have not taken into account the characteristics of the user performing the search. In this chapter, the impact of translating queries' terms between lay and medico-scientific terminology, in users with different levels of health literacy and topic familiarity, is evaluated. Findings demonstrate that medico-scientific queries demand more from the users and are mostly aimed at health professionals. In addition, these queries retrieve documents that are less readable and less well understood by users. Despite this, medico-scientific queries are associated with higher precision in the top-10 retrieved documents results and tend slightly to generate knowledge with less incorrect contents, the researchers concluded that search engines should provide query suggestions with medico-scientific terminology, whenever the user is able to digest it, that is, in users above the lowest levels of health literacy and topic familiarity. On the other hand, retrieval systems should provide lay alternative queries in users with inadequate health literacy or in those unfamiliar with a topic. In fact, the quantity of incorrect contents in the knowledge that emerges from a medico-scientific session tends to decrease with topic familiarity and health literacy. In terms of topic familiarity, the opposite happens with Graded Average Precision. Moreover, users most familiar with a topic tend to have higher motivational relevance with medico-scientific queries than with lay queries. This work is the first to consider user context features while studying the impact of a query processing technique in several aspects of the retrieval process, including the medical accuracy of the acquired knowledge. © 2015 by Emerald Group Publishing Limited.

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