2015
Authors
Esteves, MS; Azevedo Perdicoulis, TPA; dos Santos, PL;
Publication
CONTROLO'2014 - PROCEEDINGS OF THE 11TH PORTUGUESE CONFERENCE ON AUTOMATIC CONTROL
Abstract
System Identification (SI) is a methodology for building mathematical models of dynamic systems from experimental data, i.e., using measurements of the system input/output (IO) signals to estimate the values of adjustable parameters in a given model structure. The process of SI requires some steps, such as measurement of the IO signals of the system in time or frequency domain, selection of a candidate model structure, choice and application of a method to estimate the value of the adjustable parameters in the candidate model structure, validation and evaluation of the estimated model to see if the model is right for the application needs, which should be done preferably with a different set of data, [PS] and [Lj1]. © 2015 Springer International Publishing.
2015
Authors
Rynkevic, R; Silva, MF; Marques, MA;
Publication
BIOMATERIALS AND BIOMECHANICS IN BIOENGINEERING
Abstract
A problem faced by oil companies is the maintenance of the location register of pipelines that cross the surf zone, the regular survey of their location, and also their inspection. A survey of the state of art did not allow identifying operating systems capable of executing such tasks. Commercial technologies available on the market also do not address this problem and/or do not satisfy the presented requirements. A possible solution is to use robotic systems which have the ability to walk on the shore and in the surf zone, subject to existing currents and ripples, and being able to withstand these ambient conditions. In this sense, the authors propose the development of a spider crab biologically inspired robot to achieve those tasks. Based on these ideas, this work presents a biomechanical study of the spider crab, its modeling and simulation using the SimMechanics toolbox of Matlab/Simulink, which is the first phase of this more vast project. Results show a robot model that is moving in an "animal like" manner, the locomotion, the algorithm presented in this paper allows the crab to walk sideways, in the desired direction.
2015
Authors
Lopes Dos Santos, P; Ramos, JA; Martins De Carvalho, JL;
Publication
2007 European Control Conference, ECC 2007
Abstract
In this paper we introduce a recursive subspace system identification algorithm for MIMO linear parameter varying systems driven by general inputs and a white noise time varying parameter vector. The new algorithm is based on a convergent sequence of linear deterministic-stochastic state-space approximations, thus considered a Picard based method. Such methods have proven to be convergent for the bilinear state-space system identification problem. The key to the proposed algorithm is the fact that the bilinear term between the time varying parameter vector and the state vector behaves like a white noise process. Using a linear Kalman filter model, the bilinear term can be efficiently estimated and then used to construct an augmented input vector at each iteration. Since the previous state is known at each iteration, the system becomes linear, which can be identified with a linear-deterministic subspace algorithm such as MOESP, N4SID, or CVA. Furthermore, the model parameters obtained with the new algorithm converge to those of a linear parameter varying model. Finally, the dimensions of the data matrices are comparable to those of a linear subspace algorithm, thus avoiding the curse of dimensionality. © 2007 EUCA.
2015
Authors
Rodrigues, JGP; Kaiseler, M; Aguiar, A; Cunha, JPS; Barros, J;
Publication
IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS
Abstract
The experience of daily stress among bus drivers has shown to affect physical and psychological health, and can impact driving behavior and overall road safety. Although previous research consistently supports these findings, little attention has been dedicated to the design of a stress detection method able to synchronize physiological and psychological stress responses of public bus drivers in their day-to-day routine work. To overcome this limitation, we propose a mobile sensing approach to detect georeferenced stress responses and facilitate memory recall of the stressful situations. Data were collected among public bus drivers in the city of Porto, Portugal (145 h, 36 bus drivers, +2300 km), and results supported the validation of our approach among this population and allowed us to determine specific stressor categories within certain areas of the city. Furthermore, data collected throughout the city allowed us to produce a citywide "stress map" that can be used for spotting areas in need of local authority intervention. The enriching findings suggest that our system can be a promising tool to support applied occupational health interventions for public bus drivers and guide authorities' interventions to improve these aspects in "future" cities.
2015
Authors
Yang J.; Huang T.; Petralia F.; Long Q.; Zhang B.; Argmann C.; Zhao Y.; Mobbs C.V.; Schadt E.E.; Zhu J.; Tu Z.; Ardlie K.G.; Deluca D.S.; Segrè A.V.; Sullivan T.J.; Young T.R.; Gelfand E.T.; Trowbridge C.A.; Maller J.B.; Tukiainen T.; Lek M.; Ward L.D.; Kheradpour P.; Iriarte B.; Meng Y.; Palmer C.D.; Winckler W.; Hirschhorn J.; Kellis M.; MacArthur D.G.; Getz G.; Shablin A.A.; Li G.; Zhou Y.H.; Nobel A.B.; Rusyn I.; Wright F.A.; Lappalainen T.; Ferreira P.G.; Ongen H.; Rivas M.A.; Battle A.; Mostafavi S.; Monlong J.; Sammeth M.; Mele M.; Reverter F.; Goldman J.; Koller D.; Guigo R.; McCarthy M.I.; Dermitzakis E.T.; Gamazon E.R.; Konkashbaev A.; Nicolae D.L.; Cox N.J.; Flutre T.; Wen X.; Stephens M.; Pritchard J.K.; Lin L.; Liu J.; Brown A.; Mestichelli B.; Tidwell D.; Lo E.; Salvatore M.; Shad S.; Thomas J.A.; Lonsdale J.T.; Choi C.; Karasik E.; Ramsey K.; Moser M.T.; Foster B.A.; Gillard B.M.; Syron J.; Fleming J.; Magazine H.; Hasz R.; Walters G.D.; Bridge J.P.; Miklos M.; Sullivan S.; Barker L.K.; Traino H.; Mosavel M.; Siminoff L.A.; Valley D.R.; Rohrer D.C.; Jewel S.; Branton P.; Sobin L.H.; Qi L.; Hariharan P.; Wu S.; Tabor D.; Shive C.; Smith A.M.; Buia S.A.;
Publication
Scientific Reports
Abstract
Aging is one of the most important biological processes and is a known risk factor for many age-related diseases in human. Studying age-related transcriptomic changes in tissues across the whole body can provide valuable information for a holistic understanding of this fundamental process. In this work, we catalogue age-related gene expression changes in nine tissues from nearly two hundred individuals collected by the Genotype-Tissue Expression (GTEx) project. In general, we find the aging gene expression signatures are very tissue specific. However, enrichment for some well-known aging components such as mitochondria biology is observed in many tissues. Different levels of cross-tissue synchronization of age-related gene expression changes are observed, and some essential tissues (e.g., heart and lung) show much stronger "co-aging" than other tissues based on a principal component analysis. The aging gene signatures and complex disease genes show a complex overlapping pattern and only in some cases, we see that they are significantly overlapped in the tissues affected by the corresponding diseases. In summary, our analyses provide novel insights to the co-regulation of age-related gene expression in multiple tissues; it also presents a tissue-specific view of the link between aging and age-related diseases.
2015
Authors
Borel, C; Ferreira, PG; Santoni, F; Delaneau, O; Fort, A; Popadin, KY; Garieri, M; Falconnet, E; Ribaux, P; Guipponi, M; Padioleau, I; Carninci, P; Dermitzakis, ET; Antonarakis, SE;
Publication
American Journal of Human Genetics
Abstract
The study of gene expression in mammalian single cells via genomic technologies now provides the possibility to investigate the patterns of allelic gene expression. We used single-cell RNA sequencing to detect the allele-specific mRNA level in 203 single human primary fibroblasts over 133,633 unique heterozygous single-nucleotide variants (hetSNVs). We observed that at the snapshot of analyses, each cell contained mostly transcripts from one allele from the majority of genes; indeed, 76.4% of the hetSNVs displayed stochastic monoallelic expression in single cells. Remarkably, adjacent hetSNVs exhibited a haplotype-consistent allelic ratio; in contrast, distant sites located in two different genes were independent of the haplotype structure. Moreover, the allele-specific expression in single cells correlated with the abundance of the cellular transcript. We observed that genes expressing both alleles in the majority of the single cells at a given time point were rare and enriched with highly expressed genes. The relative abundance of each allele in a cell was controlled by some regulatory mechanisms given that we observed related single-cell allelic profiles according to genes. Overall, these results have direct implications in cellular phenotypic variability. © 2015 The American Society of Human Genetics.
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