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Publications

2015

Supporting the Design of an Ambient Assisted Living System Using Virtual Reality Prototypes

Authors
Campos, JC; Abade, T; Silva, JL; Harrison, MD;

Publication
AMBIENT ASSISTED LIVING: ICT-BASED SOLUTIONS IN REAL LIFE SITUATIONS

Abstract
APEX, a framework for prototyping ubiquitous environments, is used to design an Ambient Assisted Living (AAL) system to enhance a care home for older people. The environment allows participants in the design process to experience the proposed design and enables developers to explore the design by rapidly developing alternatives. APEX provided the means to explore alternative designs through a virtual environment. It provides a mediating representation (a boundary object) allowing users to be involved in the design process. A group of residents in a city-based care home were involved in the design. The paper describes the design process and lessons learnt for the design of AAL systems.

2015

Optimal Coordination of Battery Energy Storages and Demand Response Programs with Application to Wind Integration

Authors
Heydarian Forushani, E; Golshan, MEH; Shafie khah, M; Catalao, JPS;

Publication
2015 IEEE INTERNATIONAL CONFERENCE ON SMART ENERGY GRID ENGINEERING (SEGE 2015)

Abstract
The introduction of Variable Renewable Energy Sources (VRESs) such as wind to the future power portfolio can have significant effects on raising the daily net load variations and consequently may cause more operation costs as well as inefficient operation of units, and even in the worst case put the system's security at risk. On this basis, the need for a greater flexibility is essential to ensure efficient operation of the power system with significant amount of VRESs. Under this perspective, this paper presents a coordinated dispatch model in energy and reserve markets taking into account the role of bulk Battery Energy Storages (BESs) as well as Demand Response Programs (DRPs) as most favorable options in order to achieve a greater flexibility based on a Network Constrained Unit Commitment (NCUC) model. Numerical studies indicate that the coordinated operation of the existing units and the new flexible technologies could provide this additional required flexibility with a reasonable cost.

2015

Implementing a Linear Algebra Approach to Data Processing

Authors
Pontes, R; Matos, M; Oliveira, JN; Pereira, JO;

Publication
Grand Timely Topics in Software Engineering - International Summer School GTTSE 2015, Braga, Portugal, August 23-29, 2015, Tutorial Lectures

Abstract
Data analysis is among the main strategies of our time for enterprises to take advantage of the vast amounts of data their systems generate and store everyday. Thus the standard relational database model is challenged everyday to cope with quantitative operations over a traditionally qualitative, relational model. A novel approach to the semantics of data is based on (typed) linear algebra (LA), rather than relational algebra, bridging the gap between data dimensions and data measures in a unified way. Also, this bears the promise of increased parallelism, as most operations in LA admit a ‘divide & conquer’ implementation. This paper presents a first experiment in implementing such a typed linear algebra approach and testing its performance on a data distributed system. It presents solutions to some theoretical limitations and evaluates the overall performance. © Springer International Publishing AG 2017.

2015

Low-complexity MARG algorithms for increased accuracy in space pointing devices

Authors
Rasteiro, M; Costelha, H; Bento, L; Barata, M; Assuncao, P;

Publication
2015 IEEE 1st International Workshop on Consumer Electronics - Novi Sad, CE WS 2015

Abstract
This paper addresses the accuracy of space pointing devices when using absolute orientation for interaction with multimedia content. Classical accurate fusion algorithms are computationally intensive, therefore their implementation in low-energy consumption devices is a challenging task. To tackle this problem, a performance study of a relevant set of COTS MARG sensor units with low-complexity algorithms, is presented in this study. Performance evaluation tests are carried out under harsh conditions to observe the algorithms response in a non-trivial environment. The results demonstrate that the implementation of low-complexity algorithms using low-cost sensors, can provide acceptable accuracy in comparison with the more complex state-of-the-art sensors/algorithms. These results pave the way for faster adoption of absolute orientation-based pointing devices in interactive multimedia applications. © 2015 IEEE.

2015

GreenDroid: A Tool for Analysing Power Consumption in the Android Ecosystem

Authors
Couto, M; Cunha, J; Fernandes, JP; Pereira, R; Saraiva, J;

Publication
2015 IEEE 13th International Scientific Conference on Informatics

Abstract
This paper presents GreenDroid, a tool for monitoring and analyzing power consumption for the Android ecosystem. This tool instruments the source code of a giving Android application and is able to estimate the power consumed when running it. Moreover, it uses advanced classification algorithms to detect abnormal power consumption and to relate them to fragments in the source code. A set of graphical results are produced that help software developers to identify abnormal power consumption in their source code.

2015

Task partitioning and priority assignment for distributed hard real-time systems

Authors
Garibay Martinez, R; Nelissen, G; Ferreira, LL; Pinho, LM;

Publication
JOURNAL OF COMPUTER AND SYSTEM SCIENCES

Abstract
In this paper, we propose the Distributed using Optimal Priority Assignment (DOPA) heuristic that finds a feasible partitioning and priority assignment for distributed applications based on the linear transactional model. DOPA partitions the tasks and messages in the distributed system, and makes use of the Optimal Priority Assignment (OPA) algorithm known as Audsley's algorithm, to find the priorities for that partition. The experimental results show how the use of the OPA algorithm increases in average the number of schedulable tasks and messages in a distributed system when compared to the use of Deadline Monotonic (DM) usually favoured in other works. Afterwards, we extend these results to the assignment of Parallel/Distributed applications and present a second heuristic named Parallel-DOPA (P-DOPA). In that case, we show how the partitioning process can be simplified by using the Distributed Stretch Transformation (DST), a parallel transaction transformation algorithm introduced in [1].

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