Convergence of time - stepping schemes for passıie and extended linear complementarity systems

Generalizing recent results in [M. K. Camlibel, Complementarity Methods in the Analysis of Piecewise Linear Dynamical Systems, Ph.D. thesis, Center for Economic Research, Tilburg University, Tilburg, The Netherlands, 2001], [M. K. Camlibel, W. P. M. H. Heemels, and J. M. Schumacher, IEEE Trans. Circuits Systems I: Fund. Theory Appl., 49 (2002), pp. 349-357], and [J.-S. Pang and D. Stewart, Math. Program. Ser. A, 113 (2008), pp. 345-424], this paper provides an in-depth analysis of time-stepping methods for solving initial-value and boundary-value, non-Lipschitz linear complementarity systems (LCSs) under passivity and broader assumptions. The novelty of the methods and their analysis lies in the use of "least-norm solutions" in the discrete-time linear complementarity subproblems arising from the numerical scheme; these subproblems are not necessarily monotone and are not guaranteed to have convex solution sets. Among the principal results, it is shown that, using such least-norm solutions of the discrete-time subproblems, an implicit Euler scheme is convergent for passive initial-value LCSs; generalizations under a strict copositivity assumption and for boundary-value LCSs are also established

Convergence of Time-Stepping Schemes for Passive and Extended Linear Complementarity Systems

Generalizing recent results in [M. K. Camlibel, Complementarity Methods in the Analysis of Piecewise Linear Dynamical Systems, Ph.D. thesis, Center for Economic Research, Tilburg University, Tilburg, The Netherlands, 2001], [M. K. Camlibel, W. P. M. H. Heemels, and J. M. Schumacher, IEEE Trans. Circuits Systems I: Fund. Theory Appl., 49 (2002), pp. 349-357], and [J.-S. Pang and D. Stewart, Math. Program. Ser. A, 113 (2008), pp. 345-424], this paper provides an in-depth analysis of time-stepping methods for solving initial-value and boundary-value, non-Lipschitz linear complementarity systems (LCSs) under passivity and broader assumptions. The novelty of the methods and their analysis lies in the use of "least-norm solutions" in the discrete-time linear complementarity subproblems arising from the numerical scheme; these subproblems are not necessarily monotone and are not guaranteed to have convex solution sets. Among the principal results, it is shown that, using such least-norm solutions of the discrete-time subproblems, an implicit Euler scheme is convergent for passive initial-value LCSs; generalizations under a strict copositivity assumption and for boundary-value LCSs are also established.</p

Enhancement of Biohydrogen and Biomethane Production from Wastes Using Ultrasonication

This thesis demonstrated the feasibility of using ultrasonication to solubilize the particulate matter, suppress the growth of methanogens, and enrich the biohydrogen producers, thus overcoming the main challenge of biohydrogen systems i.e. long-term stability and contamination with methanogens. Furthermore, this work emphasized the benefits of applying ultrasonication inside a bioreactor over using it as a pretreatment for biohydrogen and biomethane production from wastes. The results of this work showed that sonicating hog manure at specific energy (SE) of 500 kJ/kg TS resulted in a 20% increase in methane production and 36% increase in VSS destruction. The viability of using ultrasonication as a pretreatment method for elimination of methane producers and enrichment of hydrogen producers has been confirmed at SE of 79 kJ/g TSS. Moreover, hydrogen production in a novel sonicated biological hydrogen reactor (SBHR), which comprised a continuous stirred tank reactor (CSTR) connected with an ultrasonic probe at the bottom of the reactor, was about 85% higher than that in a conventional CSTR. On the other hand, an extensive comparative study of five different mesophilic systems (single and two-stage with and without sonicated feed, and two-stage; SBHR followed by methane reactor) was undertaken using food waste. The results showed that sonication inside the reactor in the first stage showed superior results compared to all other systems with respect to hydrogen production, methane production, and VSS destruction. The study also confirmed the advantages of two-stage mesophilic digestion of food wastes over single-stage systems, as reflected by VSS destruction efficiencies in the range of 51% - 59% versus 36% - 44% at a short SRT of 7 days

Gaze Detection and Analysis for Initiating Joint Activity in Industrial Human-Robot Collaboration

Collaborative robots (cobots) are widely used in industrial applications, yet extensive research is still needed to enhance human-robot collaborations and operator experience. A potential approach to improve the collaboration experience involves adapting cobot behavior based on natural cues from the operator. Inspired by the literature on human-human interactions, we conducted a wizard-of-oz study to examine whether a gaze towards the cobot can serve as a trigger for initiating joint activities in collaborative sessions. In this study, 37 participants engaged in an assembly task while their gaze behavior was analyzed. We employ a gaze-based attention recognition model to identify when the participants look at the cobot. Our results indicate that in most cases (84.88\%), the joint activity is preceded by a gaze towards the cobot. Furthermore, during the entire assembly cycle, the participants tend to look at the cobot around the time of the joint activity. To the best of our knowledge, this is the first study to analyze the natural gaze behavior of participants working on a joint activity with a robot during a collaborative assembly task.Comment: First draft for a paper submitted to Frontiers in Robotics and A

Urban Deformation Monitoring using Persistent Scatterer Interferometry and SAR tomography

This book focuses on remote sensing for urban deformation monitoring. In particular, it highlights how deformation monitoring in urban areas can be carried out using Persistent Scatterer Interferometry (PSI) and Synthetic Aperture Radar (SAR) Tomography (TomoSAR). Several contributions show the capabilities of Interferometric SAR (InSAR) and PSI techniques for urban deformation monitoring. Some of them show the advantages of TomoSAR in un-mixing multiple scatterers for urban mapping and monitoring. This book is dedicated to the technical and scientific community interested in urban applications. It is useful for choosing the appropriate technique and gaining an assessment of the expected performance. The book will also be useful to researchers, as it provides information on the state-of-the-art and new trends in this fiel

The Ayyubid Orogen: An Ophiolite Obduction-Driven Orogen in the Late Cretaceous of the Neo-Tethyan South Margin

A minimum 5000-km long obduction-driven orogeny of medial to late Cretaceous age is located between Cyrenaica in eastern Libya and Oman. It is herein called the Ayyubid Orogen after the Ayyubid Empire that covered much of its territory. The Ayyubid orogen is distinct from other Alpide orogens and has two main parts: a western, mainly germanotype belt and an eastern mainly alpinotype belt. The germanotype belt formed largely as a result of an aborted obduction, whereas the alpinotype part formed as a result of successful and large-scale obduction events that choked a nascent subduction zone. The mainly germanotype part coincides with Erich Krenkel's Syrian Arc (Syrischer Bogen) and the alpinotype part with Ricou's  Peri-Arabian Ophiolitic Crescent (Croissant Ophiolitique péri-Arabe). These belts formed as a consequence of the interaction of one of the now-vanished Tethyan plates and Afro-Arabia. The Africa-Eurasia relative motion has influenced the orogen's evolution, but was not the main causative agent. Similar large and complex obduction-driven orogens similar to the Ayyubids may exist along the Ordovician Newfoundland/Scotland margin of the Caledonides and along the Ordovician European margin of the Uralides.SOMMAIREEntre la Cyrénaïque dans l'est de la Libye et Oman, se trouve un ceinture orogénique d’au moins 5 000 km de longueur créé par obduction au Crétacé moyen et tardif.  Nous le nommons ici l’orogène ayyoubide d’après l'empire ayyoubide qui couvrait une grande partie de son territoire.  L'orogène ayyoubide qui est distincte des autres orogènes alpides, comporte deux parties principales : une bande occidentale, principalement germanotype, et une bande orientale principalement alpinotype.  La bande germanotype s’est formée en grande partie à la suite d'une obduction avortée, tandis que la partie alpinotype s’est formée par des épisodes d’obduction à grande échelle qui ont étranglé une zone de subduction naissante.  La partie principalement germanotype coïncide avec l’arc syrien d’Erich Krenkel (Syrischer Bogen), alors que la partie alpinotype correspond au croissant ophiolitique péri-Arabe de Ricou (Croissant ophiolitique péri-Arabe).  Ces bandes se sont formées par l'interaction de l'une des plaques de la Téthys, maintenant disparues, avec l’Afro-Arabie.  Le mouvement relatif Afrique-Eurasie a influencé l'évolution de l'orogène, mais ça n’a pas été le principal facteur.  Des orogènes grandes et complexes résultant de mécanismes d’obduction similaires à l’orogène Ayyoubide peuvent exister le long de la marge des Calédonides de l'Ordovicien de Terre-Neuve/Écosse et le long de la marge européenne des Uralides de l'Ordovicien

Investigating Inter-Subject and Inter-Activity Variations in Activity Recognition Using Wearable Motion Sensors

This work investigates inter-subject and inter-activity variability of a given activity dataset and provides some new definitions to quantify such variability. The definitions are sufficiently general and can be applied to a broad class of datasets that involve time sequences or features acquired using wearable sensors. The study is motivated by contradictory statements in the literature on the need for user-specific training in activity recognition. We employ our publicly available dataset that contains 19 daily and sports activities acquired from eight participants who wear five motion sensor units each. We pre-process recorded activity time sequences in three different ways and employ absolute, Euclidean and dynamic time warping distance measures to quantify the similarity of the recorded signal patterns. We define and calculate the average inter-subject and inter-activity distances with various methods based on the raw and pre-processed time-domain data as well as on the raw and pre-processed feature vectors. These definitions allow us to identify the subject who performs the activities in the most representative way and pinpoint the activities that show more variation among the subjects. We observe that the type of pre-processing used affects the results of the comparisons but that the different distance measures do not alter the comparison results as much. We check the consistency of our analysis and results by highlighting some of our activity recognition rates based on an exhaustive set of sensor unit, sensor type and subject combinations. We expect the results to be useful for dynamic sensor unit/type selection, for deciding whether to perform user-specific training and for designing more effective classifiers in activity recognition. © 2015 The British Computer Society 2015. All rights reserved