Linear parameter-varying gain-scheduled attitude controller for an on-orbit servicing mission involving flexible large spacecraft and fuel sloshing

In this paper, a comprehensive methodology is presented for modeling an on-orbit servicing (OOS) mission scenario and designing a gain-scheduled feedback control system that can robustly meet performance requirements. This methodology accounts for uncertainties in the model, as well as significant changes in inertia and flexibility throughout the mission scenario. To capture the dynamics and interactions of all subsystems in the OOS scenario, a single linear fractional representation (LFR) was developed for the uncertain plant, taking into account the varying geometrical configuration of a robotic arm, flexible appendages and sloshing dynamics. The controller design considers the interactions between subsystems and uncertainties, as well as the time-varying and coupled flexible dynamics. Finally, the paper evaluates the robust stability and worst-case performances of the closed-loop system using a structured singular value analysis

Generalized Tsirelson Inequalities, Commuting-Operator Provers, and Multi-Prover Interactive Proof Systems

A central question in quantum information theory and computational complexity is how powerful nonlocal strategies are in cooperative games with imperfect information, such as multi-prover interactive proof systems. This paper develops a new method for proving limits of nonlocal strategies that make use of prior entanglement among players (or, provers, in the terminology of multi-prover interactive proofs). Instead of proving the limits for usual isolated provers who initially share entanglement, this paper proves the limits for "commuting-operator provers", who share private space, but can apply only such operators that are commutative with any operator applied by other provers. Commuting-operator provers are at least as powerful as usual isolated but prior-entangled provers, and thus, limits for commuting-operator provers immediately give limits for usual entangled provers. Using this method, we obtain an n-party generalization of the Tsirelson bound for the Clauser-Horne- Shimony-Holt inequality for every n. Our bounds are tight in the sense that, in every n-party case, the equality is achievable by a usual nonlocal strategy with prior entanglement. We also apply our method to a 3-prover 1-round binary interactive proof for NEXP. Combined with the technique developed by Kempe, Kobayashi, Matsumoto, Toner and Vidick to analyze the soundness of the proof system, it is proved to be NP-hard to distinguish whether the entangled value of a 3-prover 1-round binary-answer game is equal to 1 or at most 1-1/p(n) for some polynomial p, where n is the number of questions. This is in contrast to the 2-prover 1-round binary-answer case, where the corresponding problem is efficiently decidable. Alternatively, NEXP has a 3-prover 1-round binary interactive proof system with perfect completeness and soundness 1-2^{-poly}.Comment: 20 pages. v2: An incorrect statement in the abstract about the two-party case is corrected. Relation between this work and a preliminary work by Sun, Yao and Preda is clarifie

Linear parameter-varying gain-scheduled attitude controller for an on-orbit servicing mission involving flexible large spacecraft and fuel sloshing

In this paper, a comprehensive methodology is presented for modeling an on-orbit servicing (OOS) mission scenario and designing a gain-scheduled feedback control system that can robustly meet performance requirements. This methodology accounts for uncertainties in the model, as well as significant changes in inertia and flexibility throughout the mission scenario. To capture the dynamics and interactions of all subsystems in the OOS scenario, a single linear fractional representation (LFR) was developed for the uncertain plant, taking into account the varying geometrical configuration of a robotic arm, flexible appendages and sloshing dynamics. The controller design considers the interactions between subsystems and uncertainties, as well as the time-varying and coupled flexible dynamics. Finally, the paper evaluates the robust stability and worst-case performances of the closed-loop system using a structured singular value analysis

The importance of applying computational creativity to scientific and mathematical domains

Science and mathematics are currently underrepresented in the computational creativity (CC) community. We discuss why the CC community should apply their work to mathematical and scientific domains, and argue that this would be mutually beneficial for the domains in question. We identify a key challenge in Automated Reasoning – that it has not achieved widespread adoption by mathematicians; and one in Automated Scientific Discovery – the need for communicability of automatically generated scientific knowledge. We recommend that CC researchers help to address these two challenges by: (i) applying systems based on cognitive mechanisms to scientific and mathematical domains; (ii) employing experience in building and evaluating interactive systems to this context; and (iii) using expertise in automatically producing framing functionality to enhance the communicability of automatically generated scientific knowledge.EPSRC funded project EP/P017320/1 "Example-driven machine-human collaboration in mathematics

RECY-Car - Market analysis and technical approach of the end of life vehicle waste

Treball desenvolupat dins el marc del programa 'European Project Semester' i l'"International Design Semester".The following project took place in the European project semester in spring 2016 and was settled at the Universitat Politècnica de Catalunya in Vilanova I la Geltrù. This project was initiated by PICVISA, a sub company of the Calaf Group. For example, they are offering some material treatments like sorting of recycling materials. This recycling is for today’s society getting a very important topic because of the environmental pollution and the limited natural resources. But for some specific materials a way to recycle is still missing. The goals of this project were to describe the end of life vehicle recycling and finally solve a specific sorting problem of the company. Therefore, a thoroughly research of the actual literature was done to describe the used dismantling techniques, the materials of a car and reuse possibilities. Also there is an overview of all the different actual sorting techniques which are existing in the market. All these research topics lead to some materials which cannot be sorted at the moment. One of these materials are plastics when they are black coloured. This is also the specific problem of PICVISA. In order to estimate the market for this type of materials, there is a market analysis of the end of life vehicle treatment done. This carried out, that there is a quite huge market for this specific type of materials (50-100 M € in whole Europe). That’s why it seems to be a good idea continue working in this business field. So the next step is a brainstorming which collects several different thoughts to solve the issue and also the criteria to assess them. Then, these criteria are ranked regarding to their importance with an analytical hierarchy process. With this it is possible to evaluate each idea in a decision matrix. This leads to the most proper solution according to the given criteria. In this case the choice was an electrostatic sorting method. In this method, the plastic particles are charged electrostatically, in this use, because of the friction between the single particles (tribo-charging). Because of the electrostatic effects and unequal dielectric constants of the plastics, these materials are charged differently. So it is possible to separate them in a high voltage field. In order to separate several types of plastic, only more of those machines are needed in a row, because there is a tribo-electric charging row among all the plastics

X-ray absorption study of the local structure at the NiO/oxide interfaces

This work reports an X-ray absorption near-edge structure (XANES) spectroscopy study at the Ni K-edge in the early stages of growth of NiO on non-ordered SiO2, Al2O3 and MgO thin films substrates. Two different coverages of NiO on the substrates have been studied. The analysis of the XANES region shows that for high coverages (80 Eq-ML) the spectra are similar to that of bulk NiO, being identical for all substrates. In contrast, for low coverages (1 Eq-ML) the spectra differ from that of large coverages indicating that the local order around Ni is limited to the first two coordination shells. In addition, the results also suggest the formation of cross-linking bonds Ni - O - M (M = Si, Al, Mg) at the interfaceThis work was partially supported by the Spanish CONSOLIDER Project FUNCOAT CSD2008-00023, the ENE2010-21198-C04-04 and MAT2011-27573-C04-04 projects and by the Aragón DGA NETOSHIMA grant. We acknowledge the Spanish Ministerio de Ciencia e Innovación and CSIC for financial support and for provision of synchrotron radiation and we would like to thank the staff of SpLine at ESRF and KMC2 at BESSY II for technical support. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 2267

Forensic Data Analytics for Anomaly Detection in Evolving Networks

In the prevailing convergence of traditional infrastructure-based deployment (i.e., Telco and industry operational networks) towards evolving deployments enabled by 5G and virtualization, there is a keen interest in elaborating effective security controls to protect these deployments in-depth. By considering key enabling technologies like 5G and virtualization, evolving networks are democratized, facilitating the establishment of point presences integrating different business models ranging from media, dynamic web content, gaming, and a plethora of IoT use cases. Despite the increasing services provided by evolving networks, many cybercrimes and attacks have been launched in evolving networks to perform malicious activities. Due to the limitations of traditional security artifacts (e.g., firewalls and intrusion detection systems), the research on digital forensic data analytics has attracted more attention. Digital forensic analytics enables people to derive detailed information and comprehensive conclusions from different perspectives of cybercrimes to assist in convicting criminals and preventing future crimes. This chapter presents a digital analytics framework for network anomaly detection, including multi-perspective feature engineering, unsupervised anomaly detection, and comprehensive result correction procedures. Experiments on real-world evolving network data show the effectiveness of the proposed forensic data analytics solution.Comment: Electronic version of an article published as [Book Series: World Scientific Series in Digital Forensics and Cybersecurity, Volume 2, Innovations in Digital Forensics, 2023, Pages 99-137] [DOI:10.1142/9789811273209_0004] \c{opyright} copyright World Scientific Publishing Company [https://doi.org/10.1142/9789811273209_0004

BiFeO3 films on steel substrate prepared by the polymerized complex method

Es presenta un mètode de producció de capes primes de $BiFeO_3$ per síntesi en fase líquida a baixa temperatur

Robust and adaptable dynamic response reshaping of flexible structures

This paper outlines a complete methodology for designing a control system that reshapes the dynamic response of the flexible structure to robustly match the dynamics of a given adaptable reference model. The procedure was experimentally verified on a setup developed at the European Space Agency, consisting of a cantilevered flexible plate actuated by two shakers. Angular displacements at the free tip of the plate were measured with sub-microradian resolution using a laser autocollimator. Following a comprehensive system identification phase, mathematical models of the uncertain plant were extracted. The models reliably fit the experimental data and were used to synthesize a low order and high bandwidth structured Linear Parameter Varying controller. The controller was designed by taking into account the limits of achievable performance and the closed loop effectively constrained the flexible structure to behave like it was made out of an adaptable material. The robust stability and worst case performances were assessed by means of a structured singular value analysis and excellent agreement between theoretical predictions and experimental results was observed

Robust Active Mirror Control Based on Hybrid Sensing for Spacecraft Line-of-Sight Stabilization

Modern space-observation missions demand stringent pointing requirements that motivated a significant amount of research on the topic of microvibration isolation and line-of-sight stabilization systems. While disturbances can be reduced by mounting some of the noisy equipment on various isolation platforms, residual vibrations can still propagate through and be amplified by the flexible structure of the spacecraft. In order to alleviate these issues, the line of sight must also be actively controlled at the payload level. However, such systems typically have to rely solely on low-frequency sensors based on image processing algorithms. The goal of this article is to present a model-based control methodology that can increase the bandwidth of such systems by making use of additional rate sensors mounted on the main disturbance elements impacting the optical path. Following a comprehensive model identification and uncertainty quantification part, the robust control strategy is designed to account for plant uncertainty and provide formal worst case performance guarantees. Excellent agreement between theoretical prediction and experimental results are obtained on a test bench developed at the European Space Agency