Adding aspect-oriented features to MATLAB

This paper presents an approach to enrich MATLAB with aspect-oriented extensions to experiment different implementation features. The language we propose aims to configure the low-level data representation of real variables and expressions, to a specifically-tailored fixed-point data representation that benefits from a more efficient support by computing engines (e.g., DSPs, application-specific architectures, etc.) without specific hardware-based floating point units. Additionally, the approach aims to help developers to introduce handlers and monitoring features, and to configure a function with an optimized implementation.FCT under projects PPC-VM (POSI/CHS/47158/2002) and SOFTAS (POSI/EIA/ 60189/200

A domain-specific language for parallel and grid computing

This paper overviews a Domain-Specific Language (DSL) for parallel and grid computing, layered on top of AspectJ. This DSL aims to bridge the gap between sequential code and parallel/grid applications, by avoiding invasive source code changes in scientific applications. Moreover, it aims to promote the localization of parallelization and gridification issues into well defined modules that can be (un)plugged (from)to existing scientific applications. This paper builds on previous work based on AspectJ and presents the main motivations for implementing a DSL in preference to a pure-AspectJ solution. The paper presents the DSL's design rationale, overviews current implementation and open research issues.(undefined)info:eu-repo/semantics/publishedVersio

Is FFT Fast Enough for Beyond-5G Communications?

This paper studies the impact of computational complexity on the throughput limits of different Discrete Fourier Transform (DFT) algorithms (such as FFT and straightforward DFT) in the context of OFDM-based waveforms. Based on the spectro-computational complexity (SC) analysis, it is verified that the complexity of an $N$-point FFT grows faster than the number of bits in the OFDM symbol. Thus, the useful throughput of FFT nullifies on $N$. Also, because FFT demands $N$ to be a power of two $2^i$ ($i>0$), the spectrum widening leads to an exponential complexity on $i$, i.e. $O(2^ii)$. To overcome these limitations, we consider the alternative frequency-time transform formulation of Vector OFDM (V-OFDM), in which an $N$-point FFT is replaced by $N/L$ ($L$$>$$0$) smaller $L$-point FFTs to mitigate the cyclic prefix overhead of OFDM. Building on that, we replace FFT by the straightforward DFT algorithm to release the V-OFDM parameters from growing as powers of two and to benefit from flexible numerology (e.g., $L=3$, $N=156$). Besides, by setting $L$ to $\Theta(1)$, the resulting solution can run linearly on $N$ (rather than exponentially on $i$) while sustaining a non null throughput as $N$ grows.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Climate change impacts on water resources and reservoir management: uncertainty and adaptation for a mountain catchment in Northeast Portugal

Reservoirs often play an important role in mitigating water supply problems. However, the implications of climate change are not always considered in reservoir planning and management. This study aimed to address this challenge in the Alto Sabor watershed, northeast Portugal. The study analysed whether or not the shortage of water supply can be effectively addressed through the construction of a new reservoir (two-reservoir system) by considering future climate projections. The hydrological model Soil and Water Assessment Tool (SWAT) was calibrated and validated against daily-observed discharge and reservoir volume, with a good agreement between model predictions and observations. Outputs from four General Circulation Models (GCM) for two scenarios (RCP 4.5 and 8.5) were statistically downscaled and bias-corrected with ground observations. A general increase in temperature is expected in the future while the change in precipitation is more uncertain as per the differences among climatic models. In general, annual precipitation would slightly decrease while seasonal changes would be more significant, with more precipitation in winter and much less in spring and summer. SWAT simulations suggest that the existence of two-reservoir will better solve the water supply problems under current climate conditions compared to a single-reservoir system. However in the future, the reliability of this solution will decrease, especially due to the variability of projections from the different climatic models. The solution to water supply problems in this region, adopted taking only present-day climate into account, will likely be inefficient for water supply management under future climate conditions.This work was funded by FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and by National Funds through FCT - Foundation for Science and Technology under the project PTDC/AAG-MAA/4539/2012 / FCOMP-01-0124-FEDER-027863 (IND_CHANGE). J.P. Nunes was financially supported by FCT (Portuguese Science Foundation), and the European Social Fund through post-doctoral grant (SFRH/BPD/87571/2012). A.T. Monteiro is supported by FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and by National Funds through FCT - Foundation for Science and Technology under the UID/BIA/50027/2013 and POCI-01-0145-FEDER-006821. The authors would like to thank the Municipality of Bragança for the datasets on water inflows.info:eu-repo/semantics/publishedVersio

Mitochondrial membrane lipid remodeling in pathophysiology: A new target for diet and therapeutic interventions

Mitochondria are arbiters in the fragile balance between cell life and death. These organelles present an intricate membrane system, with a peculiar lipid composition and displaying transverse as well as lateral asymmetry. Some lipids are synthesized inside mitochondria, while others have to be imported or acquired in the form of precursors. Here, we review different processes, including external interventions (e.g., diet) and a range of biological events (apoptosis, disease and aging), which may result in alterations of mitochondrial membrane lipid content. Cardiolipin, the mitochondria lipid trademark, whose biosynthetic pathway is highly regulated, will deserve special attention in this review. The modulation of mitochondrial membrane lipid composition, especially by diet, as a therapeutic strategy for the treatment of some pathologies will be also addressed.Work at the authors laboratory is supported by the Portuguese Foundation for Science and Technology and FEDER/COMPETE (research Grants PTDC-QUI-QUI-101409-2008; PTDC/QUI-BIQ/ 103001/2008 and Pest-C/SAU/LA0001/2013-2014). J.P.M. acknowledges FCT for Ph.D. Grant SFRH/BD/37626/2007

A domain-specific aspect language for transforming MATLAB programs

Aspect-oriented programming provides powerful ways to augment programs with information out of the scope of the base language while avoiding harming code readability and thus portability. MATLAB is a popular modeling/programming language that will strongly benefit of aspect-oriented programming features. For instance, MATLAB programmers could use aspects to provide information such as restrictions on allowed data types and/or values, monitoring specific aspects of the execution such as the effective dataset sizes or if a given variable ever assumes a specific value, without “polluting” the code with “check code”. This paper describes the main concepts of a domain-specific aspect language (DSAL) for specifying transformations of MATLAB programs in view of supporting optimizations by facilitating the experimentation of alternative implementations. This DSAL specifies aspect modules structured in three sections: intersections equivalent to AspectJ poincuts, actions equivalent to AspectJ advice, and conditions that control triggering of actions. Support for aspect composition strategies and aspect parameterization of tokens from the base program are also supported. We believe the described features complement and enhance MATLAB programming in substantial and valuable ways

Enriching MATLAB with aspect-oriented features for developing embedded systems

This article presents an approach to enrich the MATLAB language with aspect-oriented modularity features, enabling developers to experiment different implementation characteristics and to acquire runtime data and traces without polluting their base MATLAB code. We propose a language through which programmers configure the low-level data representation of variables and expressions. Examples include specifically-tailored fixed-point data representations leading to more efficient support for the underlying hardware, e.g., digital signal processors and application-specific architectures, without built-in floating point units. This approach assists developers in adding handlers and monitoring features in a non-invasive way as well as configuring MATLAB functions with optimized implementations. Different aspect modules can be used to retarget common MATLAB code bases for different purposes and implementations. We validate the proposed approach with a set of representative examples where we attain a simple way to explore a number of properties. Experiment results and collected aspect-oriented software metrics lend support to the claims on its usefulness.This work was partially supported by FCT (Portuguese Science Foundation) under the project AMADEUS (POCTI, PTDC/EIA/70271/2006)

Using multivariate statistics on detection of particular signals during production of knitwear

This paper reports the recent developments in the pursuit to correctly locate, identify and distinguish faults during production of weft knitted fabrics. For this purpose a major textile parameter – yarn input tension (YIT) - is analyzed by means of signal processing techniques. An overview of the entire process of gathering the information and fault detection is presented. For the purpose of distinguishing faults, Multivariate statistical methods, namely cluster and discriminant analysis are used, results presented and discussed. Finally, some conclusions are drawn from the obtained results and future developments are addressed.Fundação para a Ciência e a Tecnologia (FCT) - project POSI/SRI/39824/2001