pinecone/core-2020-05-10-deduplication huggingface dataset:
Set-valued observer-based active fault-tolerant model predictive control

This paper proposes an integrated actuator and sensor active fault-tolerant model predictive control scheme. In this scheme, fault detection is implemented by using a set-valued observer, fault isolation (FI) is performed by set manipulations, and fault-tolerant control is carried out through the design of a robust model predictive control law. In this paper, a set-valued observer is used to passively complete the fault detection task, while FI is actively performed by making use of the constraint-handling capability of robust model predictive control. The set-valued observer is chosen to implement fault detection and isolation (FDI) because of its simple mathematical structure that is not affected by the type of faults such as sensor, actuator, and system-structural faults. This means that only one set-valued observer is needed to monitor all considered actuator and sensor statuses (health and fault) and to carry out the fault detection and isolation task instead of using a bank of observers (each observer matching a health/fault status). Furthermore, in the proposed scheme, the advantage of robust model predictive control is that it can effectively deal with system constraints, disturbances, and noises and allow to implement an active FI strategy, which can improve FI sensitivity when compared with the passive FI methods. Finally, a case study based on the well-known two-tank system is used to illustrate the effectiveness of the proposed fault-tolerant model predictive control scheme.Peer ReviewedPostprint (author's final draft
A trajectory-based sampling strategy for sequentially refined metamodel management of metamodel-based dynamic optimization in mechatronics

Dynamic optimization problems based on computationally expensive models that embody the dynamics of a mechatronic system can result in prohibitively long optimization runs. When facing optimization problems with static models, reduction in the computational time and thus attaining convergence can be established by means of a metamodel placed within a metamodel management scheme. This paper proposes a metamodel management scheme with a dedicated sampling strategy when using computationally demanding dynamic models in a dynamic optimization problem context. The dedicated sampling strategy enables to attain dynamically feasible solutions where the metamodel is locally refined during the optimization process upon satisfying a feasibility-based stopping condition. The samples are distributed along the iterate trajectories of the sequential direct dynamic optimization procedure. Algorithmic implementation of the trajectory-based metamodel management is detailed and applied on two case studies involving dynamic optimization problems. These numerical experiments illustrate the benefits of the presented scheme and its sampling strategy on the convergence properties. It is shown that the acceleration of the solution time of the dynamic optimization problem can be achieved when evaluating the metamodel that is lower than 90% compared to the computationally expensive model
Optimal sequence of landfills in solid waste management

Given that landfills are depletable and replaceable resources, the right approach, when dealing with landfill management, is that of designing an optimal sequence of landfills rather than designing every single landfill separately. In this paper we use Optimal Control models, with mixed elements of both continuous and discrete time problems, to determine an optimal sequence of landfills, as regarding their capacity and lifetime. The resulting optimization problems involve splitting a time horizon of planning into several subintervals, the length of which has to be decided. In each of the subintervals some costs, the amount of which depends on the value of the decision variables, have to be borne. The obtained results may be applied to other economic problems such as private and public investments, consumption decisions on durable goods, etc
The role of symplectic integrators in optimal control

International audienceFor general optimal control problems, Pontryagin's maximum principle gives necessary optimality conditions which are in the form of a Hamiltonian differential equation. For its numerical integration, symplectic methods are a natural choice. This article investigates to which extent the excellent performance of symplectic integrators for long-time integrations in astronomy and molecular dynamics carries over to problems in optimal control. Numerical experiments supported by a backward error analysis show that, for problems in low dimension close to a critical value of the Hamiltonian, symplectic integrators have a clear advantage. This is illustrated using the Martinet case in sub-Riemannian geometry. For problems like the orbital transfer of a spacecraft or the control of a submerged rigid body such an advantage cannot be observed. The Hamiltonian system is a boundary value problem and the time interval is in general not large enough so that symplectic integrators could benefit from their structure preservation of the flow
Robust sliding mode design for uncertain stochastic systems based on H∞ control method

The official published version can be found at the link below.In this paper, the design problem of sliding mode control (SMC) is addressed for uncertain stochastic systems modeled by Itô differential equations. There exist the parameter uncertainties in both the state and input matrices, as well as the unmatched external disturbance. The key feature of this work is the integration of SMC method with H∞ technique such that the robust stochastic stability with a prescribed disturbance attenuation level  can be achieved. A sufficient condition for the existence of the desired sliding mode controller is obtained via linear matrix inequalities. The reachability of the specified sliding surface is proven. Finally, a numerical simulation example is presented to illustrate the proposed method.This work was funded by The Royal Society of the U.K.;NNSF of China. Grant Numbers: 60674015, 60674089;The Technology Innovation Key Foundation of Shanghai Municipal Education Commission. Grant Number: 09ZZ60;Shanghai Leading Academic Discipline Project. Grant Number: B50
Optimal probing control for wireless transmission when the payload is negligible

The article of record as published may be located at http://dx.doi.org/10.1002/oca.954A mobile electronic device needs to periodically connect to a stationary receiver, but the information to
transfer is minimal. One such example is the electronic bracelet used in house arrest, where the main
purpose is to inform the receiver that the person is in the house. Because the mobile device does not
know its current distance from the receiver, it has incentive to first send a low-strength signal to conserve
its battery energy. If the low-strength signal fails to reach the receiver, the mobile device then gradually
increases its signal strength until a successful connection occurs. By formulating the problem as a dynamic
program, we characterize the structure of the optimal probing policy and develop an algorithm to compute
it. We also consider a discrete approximation that can be easily implemented in practice. Numerical
examples show promising improvement of the derived policy over naive heuristic policies, and that the
derived policy is robust when there are small errors in estimating the distribution of the distance between
the mobile device and the receiver
Optimal pattern of technology adoptions under embodiment: A multi -stage optimal control approach

Cataloged from PDF version of article.By deriving the necessary conditions for a multi-stage optimal control problem where the endogenous switching instants appear as an argument of the state equation, we analyze the optimal pattern of technology adoptions under embodiment with a finite planning horizon. We show that the optimal pattern of technology adoptions depends crucially on how the growth rate advantage compares to the adjustment and the obsolescence costs inherent to embodiment. We obtain non-stationary lifetimes for the adopted technologies due to finite planning horizon. We analyze numerically the effects of planning horizon, speed of adjustment to the new technology, growth rate of technology and the impatience rate on the optimal pattern. Copyright (C) 2010 John Wiley & Sons, Ltd
Gender in a land-based theology

In Fijian Methodist discourse, the vanua (land and people) is often characterised as the foundation of the traditional order and all it entails. Indigenous theologians attend to the vanua in novel ways, especially as it is paired in a half-complementary, half-oppositional way to Christianity. The question of whether the vanua might be understood in gendered terms highlights a gap between theoretically universal values and practically patriarchal norms. In this article, I discuss several innovative thinkers on this subject: (1) women in the ‘Weavers’ theological collective; (2) the Methodist theologian and former church President Ilaitia Sevati Tuwere; and (3) a female Methodist minister, Tima, whom I interviewed in 2009. I focus especially on Tuwere's description of the ‘feminine face’ of the vanua and Tima's continual and wrenching conflict with the church's male-dominated hierarchy. Whereas Tuwere uses a quasi-feminist Christian theology to reconcile Christianity and the vanua in terms of gender, Tima implies that her experiences of conflict with older men demonstrate how Christianity and the vanua might not be fully reconcilable.Research was funded by a Discovery Project grant from the Australian Research Council
(DP0878736)
Colloidal Synthesis of Gold Semishells

This work describes a novel and scalable colloid chemistry strategy to fabricate gold semishells based on the selective growth of gold on Janus silica particles (500 nm in diameter) partly functionalized with amino groups. The modulation of the geometry of the Janus silica particles allows us to tune the final morphology of the gold semishells. This method also provides a route to fabricating hollow gold semishells through etching of the silica cores with hydrofluoric acid. The optical properties were characterized by visible near-infrared (vis-NIR) spectroscopy and compared with simulations performed using the boundary element method (BEM). These revealed that the main optical features are located beyond the NIR region because of the large core size
Building Blocks for the Construction of Bioorthogonally Reactive Peptides via Solid-Phase Peptide Synthesis

The need for post-synthetic modifications and reactive prosthetic groups has long been a limiting factor in the synthesis and study of peptidic and peptidomimetic imaging agents. In this regard, the application of biologically and chemically orthogonal reactions to the design and development of novel radiotracers has the potential to have far-reaching implications in both the laboratory and the clinic. Herein, we report the synthesis and development of a series of modular and versatile building blocks for inverse electron-demand Diels–Alder copper-free click chemistry: tetrazine-functionalized artificial amino acids. Following the development of a novel peptide coupling protocol for peptide synthesis in the presence of tetrazines, we successfully demonstrated its effectiveness and applicability. This versatile methodology has the potential to have a transformational impact, opening the door for the rapid, facile, and modular synthesis of bioorthogonally reactive peptide probes
Halogen and Hydrogen Bonding Benzothiophene Diol\ud
Derivatives: A Study Using ab initio Calculations and XRay\ud
Crystal Structure Measurements

The aim of this study is to describe and compare the supramolecular\ud
interactions, in the solid state, of chloro-, bromo-,\ud
and iodobenzothiophene diols. The compounds were obtained\ud
through organo-catalyzed reactions starting from 3-substituted\ud
halobenzothiophene carbaldehydes. Energies of the noncovalent\ud
interactions were obtained by density functional theory\ud
calculations. Bond distances and angles were found to be in\ud
accordance with those determined by X-ray structure analysis.\ud
anti-Bromobenzothiophene derivatives showed strong halogen\ud
···p interactions between bromine and the heterocyclic\ud
phenyl ring, corresponding to an energy of 7.5 kcalmol1. syn-\ud
Bromo and syn-iodo derivatives appeared to be isostructural,\ud
showing X···O (carbonyl) interactions, p stacking, and formation\ud
of extended hydrogen bonding networks. In contrast, the\ud
chloro derivatives displayed no halogen bonding interaction
Influence of polarity and activation energy in microwave-assisted organic synthesis (MAOS)

The aim of this work was to determine the parameters that have decisive roles in microwave-assisted reactions and to develop a model, using computational chemistry, to predict a priori the type of reactions that can be improved under microwaves. For this purpose, a computational study was carried out on a variety of reactions, which have been reported to be improved under microwave irradiation. This comprises six types of reactions. The outcomes obtained in this study indicate that the most influential parameters are activation energy, enthalpy, and the polarity of all the species that participate. In addition to this, in most cases, slower reacting systems observe a much greater improvement under microwave irradiation. Furthermore, for these reactions, the presence of a polar component in the reaction (solvent, reagent, susceptor, etc.) is necessary for strong coupling with the electromagnetic radiation. We also quantified that an activation energy of 20–30 kcal mol−1 and a polarity (μ) between 7–20 D of the species involved in the process is required to obtain significant improvements under microwave irradiation.Financial support from the Dirección General de Ciencia y Tecnología (DGCT) del Ministerio de Educación, Ciencia y Tecnología (España) through projects CTQ2011-22410/BQU and CTQ2011-28124-C02-01, from the Consejería de Educación y Ciencia de la Junta de Comunidades de Castilla-la Mancha (JCCM), España\ud
through project PII2I09-0100, and technical support from the High-Performance Computing Service of the University of Castilla–La Mancha (Spain) is gratefully acknowledged. A.M.R. gratefully acknowledges the Spanish Ministerio de Educación y Ciencias (MEC) for an FPU fellowship.Peer Reviewe
Hydrogen-Bonded Macrocyclic Supramolecular Systems in Solution and on Surfaces

Cyclization into closed assemblies is the most recurrent approach to realize the noncovalent synthesis of discrete, well-defined nanostructures. This review article particularly focuses on the noncovalent synthesis of monocyclic hydrogen-bonded systems that are self-assembled from a single molecule with two binding-sites. Taking advantage of intramolecular binding events, which are favored with respect to intermolecular binding in solution, can afford quantitative amounts of a given supramolecular species under thermodynamic control. The size of the assembly depends on geometric issues such as the monomer structure and the directionality of the binding interaction, whereas the fidelity achieved relies largely on structural preorganization, low degrees of conformational flexibility, and templating effects. Here, we discuss several examples described in the literature in which cycles of different sizes, from dimers to hexamers, are studied by diverse solution or surface characterization techniques. Mastering supramolecular macrocyclic molecules: Cyclization into closed assemblies is the most common approach to the noncovalent synthesis of discrete supramolecular nanostructures. This review focuses on the noncovalent synthesis of monocyclic hydrogen-bonded systems that are self-assembled from a single molecule with two binding-sites. Several examples are described in which cycles of different sizes, from dimers to hexamers, are studied by diverse solution or surface characterization techniquesThe authors gratefully acknowledge funding from the European Research Council (ERC-StG 279548) and the Spanish Ministry of Economy and Competitiveness (MINECO) (CTQ2011-23659 and CTQ2014-57729-P
Mechanism of the transmetalation of organosilanes to gold

Density functional theory (DFT) calculations were carried out to study the reaction mechanism of the first transmetalation of organosilanes to gold as a cheap fluoride-free process. The versatile gold(I) complex [Au(OH)(IPr)] permits very straightforward access to a series of aryl-, vinyl-, and alkylgold silanolates by reaction with the appropriate silane reagent. These silanolate compounds are key intermediates in a fluoride-free process that results in the net transmetalation of organosilanes to gold, rather than the classic activation of silanes as silicates using external fluoride sources. However, here we propose that the gold silanolate is not the active species (as proposed during experimental studies) but is, in fact, a resting state during the transmetalation process, as a concerted step is preferred
Alkali Metal Cation versus Proton and Methyl Cation Affinities: Structure and Bonding Mechanism

Contains fulltext :
                  166255.pdf (publisher's version ) (Open Access)We have analyzed the structure and bonding of gas-phase Cl X and [HCl X](+) complexes for X+ = H+, CH3+, Li+, and Na+, using relativistic density functional theory (DFT). We wish to establish a quantitative trend in affinities of the anionic and neutral Lewis bases Cl- and HCl for the various cations. The Cl-X bond becomes longer and weaker along X+ = H+, CH3+, Li+, and Na+. Our main purpose is to understand the heterolytic bonding mechanism behind the intrinsic (i.e., in the absence of solvent) alkali metal cation affinities (AMCA) and how this compares with and differs from those of the proton affinity (PA) and methyl cation affinity (MCA). Our analyses are based on Kohn-Sham molecular orbital (KS-MO) theory in combination with a quantitative energy decomposition analysis (EDA) that pinpoints the importance of the different features in the bonding mechanism. Orbital overlap appears to play an important role in determining the trend in cation affinities
Plugging a bipyridinium axle into multichromophoric calix[6]arene wheels bearing naphthyl units at different rims

Tris-(N-phenylureido)-calix[6]arene derivatives are heteroditopic non-symmetric molecular hosts that can form pseudorotaxane complexes with 4,4'-bipyridinium-type guests. Owing to the unique structural features and recognition properties of the calix[6]arene wheel, these systems are of interest for the design and synthesis of novel molecular devices and machines. We envisaged that the incorporation of photoactive units in the calixarene skeleton could lead to the development of systems whose working modes can be governed and monitored by means of light-activated processes. Here we report on the synthesis, structural characterization, and spectroscopic, photophysical and electrochemical investigation of two calix[6]arene wheels decorated with three naphthyl groups anchored to either the upper or lower rim of the phenylureido calixarene platform. We found that the naphthyl units interact mutually and with the calixarene skeleton in a different fashion in the two compounds, which thus exhibit a markedly distinct photophysical behavior. For both hosts, the inclusion of a 4,4'-bipyridinium guest activates energy- and/or electron-transfer processes that lead to non-trivial luminescence changes
Self-Assembly of G-Rich Oligonucleotides Incorporating a 3′-3′ Inversion of Polarity Site: A New Route Towards G-Wire DNA Nanostructures

Obtaining DNA nanostructures with potential applications in drug discovery, diagnostics, and electronics in a simple and affordable way represents one of the hottest topics in nanotechnological and medical sciences. Herein, we report a novel strategy to obtain structurally homogeneous DNA G-wire nanostructures of known length, starting from the short unmodified G-rich oligonucleotide d(5′-CGGT-3′–3′-GGC-5′) (1) incorporating a 3’–3′ inversion of polarity site. The reported approach allowed us to obtain long G-wire assemblies through 5′–5′ π–π stacking interactions in between the tetramolecular G-quadruplex building blocks that form when 1 is annealed in the presence of potassium ions. Our results expand the repertoire of synthetic methodologies to obtain new tailored DNA G-wire nanostructures
Cationic supramolecular hydrogels for overcoming the skin barrier in drug delivery

A cationic bis‐imidazolium‐based amphiphile was used to form thermoreversible nanostructured supramolecular hydrogels incorporating neutral and cationic drugs for the topical treatment of rosacea. The concentration of the gelator and the type and concentration of the drug incorporated were found to be factors that strongly influenced the gelling temperature, gel‐formation period, and overall stability and morphology. The incorporation of brimonidine tartrate resulted in the formation of the most homogeneous material of the three drugs explored, whereas the incorporation of betamethasone resulted in a gel with a completely different morphology comprising linked particles. NMR spectroscopy studies proved that these gels kept the drug not only at the interstitial space but also within the fibers. Due to the design of the gelator, drug release was up to 10 times faster and retention of the drug within the skin was up to 20 times more effective than that observed for commercial products. Experiments in vivo demonstrated the rapid efficacy of these gels in reducing erythema, especially in the case of the gel with brimonidine. The lack of coulombic attraction between the gelator-host and the guest-drug seemed particularly important in highly effective release, and the intermolecular interactions operating between them were found to lie at the root of the excellent properties of the materials for topical delivery and treatment of rosacea
Potassium‐ion‐selective fluorescent sensors to detect cereulide, the emetic toxin of B. cereus, in food samples and HeLa cells

We report the development of new chemical probes for cereulide, a toxic metabolite produced by specific strains of Bacillus cereus, through displacement of potassium cations from a preformed specific complex and a subsequent change in the fluorescence emission. For this purpose, we designed fluorescent probes for potassium cations that were suitable for displacement assays with cereulide from organic extracts. The fluorescence detection of natural cereulide in rice samples was achieved by using synthetic cereulide as a reference and a potassium fluorescent reporter, and this was found to be useful as a portable and fast method for the in situ detection of cereulide in food extracts. To study the fate of cereulide in live cells, we designed a procedure that was suitable for live‐cell microscopy imaging of HeLa cells by comparing the cellular location of the potassium fluorogenic probe, which stained intracellular endolysosomes, in the absence and presence of cereulide; we concluded that in the presence of cereulide, the fluorescence of the probe was decreased because of complexation of the potassium ions by cereulide.Ministerio\ud
de Econom&a y Competitividad, Spain (Projects CTQ2015-71353-R\ud
and AES-PI16/000496), Junta de Castilla y Lejn, Consejer&a de Educaci\ud
jn y Cultura y Fondo Social Europeo (Project BU232U13),\ud
and the European Commission, Seventh Framework Programme\ud
(Project SNIFFER FP7-SEC-2012–312411