Search results for "Classificació"
showing 9 items of 39 documents
Bayesian joint ordinal and survival modeling for breast cancer risk assessment
2016
We propose a joint model to analyze the structure and intensity of the association between longitudinal measurements of an ordinal marker and time to a relevant event. The longitudinal process is defined in terms of a proportional-odds cumulative logit model. Time-to-event is modeled through a left-truncated proportionalhazards model, which incorporates information of the longitudinal marker as well as baseline covariates. Both longitudinal and survival processes are connected by means of a common vector of random effects. General inferences are discussed under the Bayesian approach and include the posterior distribution of the probabilities associated to each longitudinal category and the …
Structural Vibration Control for a Class of Connected Multistructure Mechanical Systems
2012
Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/942910 A mathematical model to compute the overall vibrational response of connected multistructure mechanical systems is presented. Using the proposed model, structural vibration control strategies for seismic protection of multibuilding systems can be efficiently designed. Particular attention is paid to the design of control configurations that combine passive interbuilding dampers with local feedback control systems implemented in the buildings. These hybrid active-passive control strategies possess the good properties of passive contro…
Discrete-time multioverlapping controller design for structural vibration control of tall buildings under seismic excitation
2012
Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/636878 In this paper, a computationally effective strategy to obtain multioverlapping controllers via the Inclusion Principle is applied to design discrete-time state-feedback multioverlapping LQR con- trollers for seismic protection of tall buildings. To compute the corresponding control actions, the proposed semidecentralized controllers only require state information from neighboring stories. This particular configuration of information exchange allows introducing a dramatic reduction in the transmission range required for a wireless imp…
Active-passive control strategy for adjacent buildings
2011
Author's version of a chapter in the book: 2011 Proceedings of the American Control Conference. Also available from the publisher at: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=05991059 In this paper, a control strategy to mitigate the vibrational response of adjacent buildings under seismic excitation is presented. The proposed strategy combines inter-building passive actuators with active actuators placed in the building stories. The main ideas are presented by means of a simplified two-building model; however, a semi-decentralized overlapping approach via the inclusion principle has been used to impose a proper information exchange structure suitable for wireless control of larg…
Index Balearicum: An annotated check-list of the vascular plants described from the Balearic Islands
2000
190 pages, 21 figures.
Optimal passive-damping design using a decentralized velocity-feedback H-infinity approach
2012
In this work, a new strategy to design passive energy dissipation systems for vibration control of large structures is presented. The method is based on the equivalence between passive damping systems and fully decentralized static velocity-feedback controllers. This equivalence allows to take advantage of recent developments in static output-feedback control design to formulate the passive-damping design as a single optimization problem with Linear Matrix Inequality constraints. To illustrate the application of the proposed methodology, a passive damping system is designed for the seismic protection of a five-story building with excellent results. Peer Reviewed
Empirical analysis of daily cash flow time-series and its implications for forecasting
2019
Usual assumptions on the statistical properties of daily net cash flows include normality, absence of correlation and stationarity. We provide a comprehensive study based on a real-world cash flow data set showing that: (i) the usual assumption of normality, absence of correlation and stationarity hardly appear; (ii) non-linearity is often relevant for forecasting; and (iii) typical data transformations have little impact on linearity and normality. This evidence may lead to consider a more data-driven approach such as time-series forecasting in an attempt to provide cash managers with expert systems in cash management.
Estudi i aportacions a l'aprenentatge de distàncies parametritzades per matrius mètriques
2014
Alhora de construir sistemes intel·ligents capaços de sensoritzar, reconèixer i comprendre el seu entorn, una de les opcions consisteix a fer servir una mesura de distància o de dissimilitud per tal de comparar els objectes detectats. En alguns casos, la utilització de distàncies estàndard pot ser acceptable i fins i tot convenient. No obstant això, sempre existeix la possibilitat d'aprendre una distància adaptada al problema inductivament a partir d'exemples particulars. Precisament, l'aprenentatge de distàncies és un cas particular d'aprenentatge automàtic el objectiu del qual consisteix a trobar aquella funció distància que satisfà una sèrie de condicions que tenen a veure amb l'adaptaci…